th
30 Annual Graduate
Research Conference
GRADUATE RESEARCH CONFERENCE
THURSDAY, APRIL 3, 2008
1
30th Annual UMB Graduate Research
Conference
CONTENTS
Page
3
Foreword
4
Keynote Speaker Biography
5
Schedule of Events
6
Abstracts
52
Index
GRADUATE RESEARCH CONFERENCE
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30th Annual Graduate Research Conference
Foreword by GSA Executive Board
Welcome to the 30th annual Graduate Research Conference (GRC)! The Graduate Student Association of
the University of Maryland, Baltimore (UMB) has been dedicated to this project since the beginning of the school
year. Each year, the GRC familiarizes graduate students with preparing for scientific meetings, as well as the
opportunity to present results of their ongoing research in an interdisciplinary setting to peers, faculty members,
and the UMB community at large. Over 100 students from across the UMB campus will present their work as
either poster or oral presentations at this GRC, and we would like to thank each of the presenters for their time
and effort to formally communicate their achievements – we commend your hard work and devotion to your
science.
This year we will be continue to take an interdisciplinary approach to the conference which highlights
research across fields and even schools. We hope this will continue to enrich the students’ experience as well as
challenge them to apply their work to a new and broader audience. This year, GRC participants also have the
opportunity to be considered for 3 special awards. The Geriatrics and Gerontology Education and Research
Program (GGEAR) will be sponsoring awards in aging research to graduate students who have either completed
research or have research in progress in Social science/behavioral/clinical research or Bio-medical/basic science
research in the field of aging. The Women's Health Research Group will sponsor awards for graduate students or
postdoctoral fellows who have either completed research or have research in progress in Social
science/behavioral/clinical research or Bio-medical/basic science research in the field of women's health. The
Office of Commercial Ventures & Intellectual Property (CVIP), in association with the Graduate Research
Conference, is delighted to announce the first annual CVIP Translational Graduate Research Award. The award
is made in recognition of important translational research performed by a UMB graduate student and
encompasses a wide array of disciplines with biomedical or other practical applications.
The Graduate Student Association Executive Board would like to thank everyone who has contributed to
this year’ conference. Specifically, we would like to acknowledge Dr. Malinda Orlin, Vice President for Academic
Affairs and Dean of the UMB Graduate School; Dr. Erin Golembewski, Assistant Dean of the UMB Graduate
School; Tanya Tucker, Communications Manager and all the members of the UMB Graduate School office.
Additionally, we would like to thank the faculty members who have volunteered their time to serve as judges and
mentors -- your dedication to the advancement of your students here today, and everyday, is greatly appreciated.
Thank you to the GSA Program Representative volunteers for your dedication, energy, and initiative. Finally, we
would like to acknowledge the Graduate Program in Life Sciences (GPILS) and Dr. McCarthy for sponsoring our
keynote speaker Ms. Elizabeth M. Marincola, who we are privileged to have here today.
We hope that you enjoy your experience at this year’s GRC. We have worked hard to make the day as
enjoyable and informative as possible. We invite you to participate fully in this year’s conference and we look
forward to welcoming you back next year. It has truly been a privilege and honor to provide a colloquium for all
graduate students of the UMB community to present their achievements.
UMB Graduate Student Association Executive Board
Justin Kerr, President
Elena Gianulis, Vice-President
Jade Bernstein, Treasurer
Maya Matheny, Secretary
Maria C. Okafor, Graduate Council Representative
GRADUATE RESEARCH CONFERENCE
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30th Annual Graduate Research
Conference Keynote Speaker
MS. ELIZABETH M. MARINCOLA
President Society for Science & the Public
Publisher, Science News
Elizabeth Marincola is President of the nonprofit
organization Society for Science & the Public and
publisher of Science News, an award-winning weekly
magazine. Society for Science & the Public owns and
manages the Science Talent Search (formerly known as
the Westinghouse Science Talent Search, and, since
1998, the Intel Science Talent Search), the Intel
International Science & Engineering Fair and the
Discovery Channel Young Scientist Challenge.
Marincola was for fourteen years Executive
Director of the American Society for Cell Biology, a
leading scientific society in Congressional advocacy for
biomedical research funding, promoting access to the
scientific literature, and the support of women and
underrepresented minorities in science. For its work,
Marincola accepted the 2004 Presidential Award for
Excellence in Science, Mathematics and Engineering
Mentoring from the President of the United States.
The ASCB honored her service in 2002 by naming her,
with the late actor-advocate Christopher Reeve, the
first Citizen Member of the Society.
Marincola served on the founding National
Advisory Committee to PubMed Central of the
National Institutes of Health from 2000-2003, and as
Director of the Joint Steering Committee for Public
Policy from 1991-2005. She currently
serves
on the Board of Directors of the Public Library of
Science, The Women in Cell Biology
Committee of the American Society for Cell Biology,
and the Krasnow Institute for Advanced Study at
George Mason University. She is the only
nonscientist to be named the Fae Golden Kass
Lecturer at Harvard Medical School. Before
moving to Washington, Marincola was Director of
Development for Stanford University Hospital and
held other administrative posts at Stanford, where she
also earned her bachelor’s degree in 1981 and her
MBA from the Stanford Graduate School of Business
in 1986. Marincola is author or co-author of dozens
of articles published in journals and magazines
including Harvard Business Review, Cell and Science.
She has served as Principal Investigator or co-PI on
several Federal research grants. Marincola is married
to Francesco (Franco) Marincola, MD, a surgeon and
immunologist who is director of the immunogenetics
laboratory in the department of transfusion medicine
in the clinical center of the National Institutes of
Health. They have three children: James, Paula and
Rachel.
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SCHEDULE OF EVENTS
30TH Annual Graduate Research Conference
Thursday, April 3, 2008
University of Maryland, Baltimore
9:00-9:30am
BREAKFAST & REGISTRATION
9:30-12:00pm
MORNING SESSION
12:00-1:30pm
LUNCH & KEYNOTE ADDRESS:
MS. ELIZABETH M. MARINCOLA
THE OPEN ACCESS IMPERATIVE
1:30-4:00pm
AFTERNOON SESSION
4:00-5:00pm
AWARD RECEPTION
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Abstracts
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1. CHARACTERIZATION OF NOVEL
EXONIC VARIANTS IN
HYPERTENSION GENE, STK39
Dorff S.E., Wang Y., Shi X., Kim J.D.O.,
Schuldiner A.R., Chang Y-P.C.
Morning; Oral Presentation; SSW/Law
Building C-001
Hypertension is a common, complex genetic
disease. A genome-wide association
(GWA) study in the Amish Family Diabetes
Study found that variants in the STK39 gene
were significantly associated with blood
pressure (BP). STK39 encodes SPAK, a
protein kinase known to interact with other
proteins which have previously been
implicated in hyper- and hypotension. The
initial GWA signals were with intronic
variants, which are relatively common
(minor allele frequencies [MAF] =0.100.20) and might have a regulatory role in
SPAK expression. However,
characterization of all common genetic
variants that alter protein structure or
expression will further our understanding of
SPAK’s role in BP regulation. Sequencing
of the coding regions of STK39 revealed
several novel variants. In exon 11, an
A399T mutation was identified which is in
the regulatory domain of SPAK.
Genotyping in AFDS showed the minor
allele to be associated with an increase of 4
mmHg SBP and 2.5 mmHg DBP (p=0.056
and 0.244, respectively, MAF=0.025).
These results were replicated in an outbred
Caucasian population with an estimate of
effect size of 11.6 mmHg for SBP (p=0.07,
MAF=0.022). This A399T mutation creates
a putative novel phosphorylation site and is
an interesting target for phosphorylation
studies because SPAK activity is regulated
via phosphorylation by kinases such as
WNK1 and WNK4. Furthermore, four
variants were identified in exon 1, a
polymorphic 5’UTR repeat and three
insertion/deletions in the PAPA box, a
region shown to be involved in proteinprotein interactions and subcellular
localization. Research is currently
underway to develop a reliable genotyping
method for analysis of these variants in the
remaining Amish samples to determine if
they are also associated with BP.
2. RECOMBINANT EXPRESSION OF
LEE-ENCODED REGULATOR (LER)
FROM ENTEROHEMORRHAGIC
ESCHERICHIA COLI FOR
STRUCTURAL CHARACTERIZATION
Jonathan A. Levine, Jane Michalski, Keith
Inman, and James Kaper
Morning; Oral Presentation; SSW/Law
Building C-001
Diarrheagenic Escherichia coli (E. coli) are
a major cause of infant mortality worldwide.
Enterohemorrhagic E. coli (EHEC) has been
of particular concern in recent years because
of outbreaks caused by contaminated beef
and produce. The Locus of Enterocyte
Effacement (LEE) - Encoded Regulator
(Ler) from EHEC is the principal regulator
of the LEE pathogenicty island that contains
at least 5 operons, encoding virulence
factors including an adhesin, translocator,
and secreted effector proteins. The function
of Ler directly correlates to its structure, in
particular the coiled- coil region near the Cterminus, and for that reason we intend to
solve the structure of this protein by solution
Nuclear Magnetic Resonance (NMR). It has
been demonstrated that Ler does not
recognize specific nucleotide sequences but
DNA structural motifs, so the mechanism of
Ler’s recognition could be elucidated with
its structure. Using mass spectrometry and
affinity chromatography, we have identified
the native start codon and have subcloned
the gene into a high copy plasmid under
T7lac control. Here we present work in
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progress, discussion of the optimization of
our techniques, and potential alternative
approaches.
3. CXCR3, A CHEMOKINE RECEPTOR
CONTRIBUTES TO BREAST CANCER
METASTASIS
Xinrong Ma, Kelly Norsworthy, William
Rodgers, Yanchun Li, Phyllis Gimotty, Olga
Goloubeva, Namita Kundu, Michael Lipsky,
Dawn Holt, Amy M. Fulton. Univ. of
Maryland School of Medicine, Baltimore,
MD, Univ. of Pennsylvania, Philadelphia,
PA
Morning; Oral Presentation; SSW/Law
Building C-001
We detected chemokine receptor CXCR3 in
malignant epithelium of early stage breast
cancers by immunohistochemistry and the
expression levels were correlated with
significantly poorer survival. Using a
murine model of metastatic breast cancer
(line 66.1), we knocked down the CXCR3
gene by shRNA and implanted the cells into
the mammary fat pad of syngeneic
Balb/cByJ mice. Spontaneous metastasis of
66.1-shCXCR3 cells was markedly reduced
(72-94%) compared with vector control
tumor cells. At the same time, the growth of
primary tumor was not affected by CXCR3
gene silencing. Lung tumor colonization
following intravenous tumor cell injection
was also significantly reduced by CXCR3
gene knock-down. These data are in
accordance with our previous findings that a
pharmacological CXCR3 antagonist inhibits
metastatic but not primary mammary tumor
growth. We also found that immortalized
normal mammary epithelial (EpH4) cells
express CXCR3 at comparable levels to
malignant breast cells, but they respond to
CXCR3 ligands differently. Migration of
tumor cells was enhanced by ligand
stimulation, but only a negligible
chemotactic response to these ligands was
observed in EpH4 cells. CXCR3 ligands
inhibited the proliferation of EpH4 cells in a
dose-dependent manner, whereas the growth
of malignant cells was unaffected by ligand
stimulation. Signal transduction activation
patterns also differ between malignant and
normal cells. Thus, CXCR3 activation alters
the behavior of both malignant and normal
cells, but in different ways. Taken together,
these studies show that CXCR3 mediates
lung metastasis of breast cancer. The
negative correlation of CXCR3 and
longterm survival encourages the further
exploration of this receptor as a therapeutic
target.
4. STRUTURE ACTIVITY
RELATIONSHIPS OF SMALL
MOLECULES INTERFERING WITH THE
S100B-P53 INTERACTION
Melissa A. Liriano1, Paul T. Wilder1,
Shijun Zhong2, Thomas H. Charpentier1,
Kristen M. Varney1 Alexander D.
MacKerell, Jr.2, and David J. Weber1
Morning; Oral Presentation; SSW/Law
Building C-002
S100B is a 21-kD, dimeric, Ca2+ and Zn2+
binding protein that is over expressed in
many cancers including renal cell
carcinomas, reactive gliomas, and malignant
melanomas. In these tumors, S100B
contributes to tumor progression by directly
down-regulating the tumor suppressor gene
p53. In order to restore appropriate p53
levels in these cancer cells, a screening
protocol has been implemented to identify
small molecules that inhibit the S100B-p53
interaction. Specifically, a high-throughput
fluorescence polarization competition assay
(FPCA) was developed to rapidly screen a
diverse library of small drug-like molecules
that compete with the binding of a FITClabeled peptide derived from the C-terminus
of p53 (p53367-393). After a single point
competition assay, the dissociation constants
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for the top 32 inhibitors were determined.
To identify structure activity relationships
for a select set of inhibitors (i.e. those with
low dissociation constants), structural
analogs were also purchased and tested
using the FPC assay. NMR experiments
were also completed to identify the small
molecule binding site on S100B as well as
the region of the inhibitor at the small
molecule-S100B interface. The long-range
goal of these studies is to use data such as
these to develop novel therapeutics for the
treatment of malignant melanomas and other
cancers with aberrant levels of S100B.
of stereotypy. It was demonstrated that
cycad-fed rats exhibited a sleep disturbance,
shown by an increase in length and number
of bouts of rapid eye movement (REM)
sleep during the active period. This increase
in REM parallels the symptom of EDS. We
are now examining the etiology of EDS in
the cycad-fed rats. Preliminary results
suggest a key role for the lateral
hypothalamus in the development of this
early, non-motor symptom. This also reveals
a potential mechanism of action for the toxic
effects of cycad in brain areas other than
those of the basal ganglia motor circuit.
5. SLEEP ALTERATION IN AN
ENVIRONMENTAL NEUROTOXIN
INDUCED MODEL OF PARKINSON'S
DISEASE
Kimberly A. McDowell, Maria M.
Hadjimarkou, Avigail E. Rose, Sarah M.
Clark, Jessica A. Mong, Paul J. Yarowsky
Morning; Oral Presentation; SSW/Law
Building C-001
6. NEMATODE-GENERATED SERINE
PROTEASES INTERACT WITH HOST
PAR-2 TO ALTER EPITHELIAL CELL
FUNCTION.
Stiltz, Jennifer A.; Rallabhandi, Prasad;
Jaladanki, Rao N.; Netzel-Arnett, Sarah;
Antalis, Toni; Sun, Rex; Urban, Joseph F.;
Zhao, Aiping; Shea-Donohue, Terez
Morning; Oral Presentation; SSW/Law
Building C-001
Parkinson’s disease (PD) is defined as a
motor disorder resulting from decreased
dopamine in the basal ganglia circuit.
However, research now focuses on early,
non-motor symptoms of PD, such as sleep
disturbances, in an attempt to diagnose the
disease before the loss of motor function. A
sleep alteration commonly found in PD
patients is Excessive Daytime Sleepiness
(EDS), whose etiology and connection to
PD is relatively unknown. Few animal
models are able to replicate both motor and
non-motor symptoms of PD. Here, we
present a progressive rat model of PD that
displays the degeneration in motor function
and disturbances in sleep. Our study
examined the effects of prolonged
consumption of flour made from washed
seeds of the Cycas micronesia (cycad) in
male rats. A novel behavior observed was
the increase in purposeless chewing, a form
Nematode generated proteases (NGP) are
critical for worm survival in the gut, but
whether NGP interact with host proteolytic
pathways is unknown. Aim: To determine if
worm serine proteases (WSP) activate PAR2 on host intestinal epithelial cells.
Methods: Adult N. brasiliensis (Nb) were
incubated at 37°C in sterile HBSS and then
in RPMI1640 containing antibiotics, and
cultured at 37°C for 14 days. Media
containing Nb secretions were collected
daily for 3 days, pooled, and passed over a
benzamidine column to isolate WSP. HEK293 cells overexpressing PAR-2 were used
to see if WSP activate PAR-2 and the
responses compared to the PAR-2 activating
peptide, SLIGKV. PAR-2 activation was
assessed in transfected cells by measuring
cytosolic Ca2+ concentration ([Ca2+]i) by
Fura-2 fluorescence. To determine if WSP
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have biological activity, muscle-free
segments of jejunae from WT or PAR-2 KO
mice were mounted in Ussing chambers to
assess secretion (change in Isc) after
addition of vehicle, WSP, or the PAR-2
agonist, SLIGRL, to the serosal side. Other
segments were placed in microsnapwells to
measure transepithelial resistance (TER,
index of permeability), following addition of
vehicle or WSP to the mucosal side. Results:
[Ca2+]i in PAR-2-transfected cells was
increased by WSP (486% ) and by SLIGKV
(87%). Secretion was stimulated by WSP
(37±8 µÅ/cm2) or 100 µM SLIGRL (40±12
µÅ/cm2) added to the serosal side. By 90
min, mucosal exposure to WSP significantly
reduced TER (77±2% of initial TER) vs
buffer (98±9%). Conclusions: WSP interact
with luminal PAR-2 to enhance intestinal
permeability facilitating subsequent changes
in epithelial secretion by WSP acting on the
serosal side. Thus, nematodes use molecular
mimicry acting at PAR-2 to alter intestinal
epithelial function.
7. ESSENTIAL ROLE FOR CFAE TIP
PROTEIN IN CFA/I FIMBRIAE
MEDIATED ATTACHMENT OF H10407
ETEC
Baker KK, Levine MM, Barry EM
Morning; Oral Presentation; BRB 1-008
Enterotoxigenic E. Coli (ETEC) use
colonization factors (CF), or fimbriae, to
attach to the human gut mucosa resulting in
diarrheal illness. Conversely, generation of
mucosal antibodies against fimbriae results
in protective immunity by blocking
colonization of the human gut. However,
the contribution of the individual fimbriae
protein subunits in intestinal adherence
remains incompletely defined. The
epidemiologically relevant ETEC strain
H10407 expresses CFA/I fimbriae, which
are composed of multiple CfaB structural
subunits and a CfaE tip subunit. To identify
the role in attachment for CfaE, an R181A
single amino acid substitution was
introduced by recombination into the CFA/I
operon of the H10407 genome. The
substitution of R181A eliminated in vitro
human cell binding, without loss of CFA/I
fimbriae expression, as confirmed by
agglutination with anti-CFA/I sera and by
electron microscopy. The binding phenotype
was restored when the wild type cfaE gene
was supplied on a plasmid in trans. In
contrast, in trans expression of cfaE
containing amino acid 181 substitutions with
biochemically, spatially, or functionally
related amino acids did not restore the
binding phenotype. Thus the R181A single
amino acid mutation in cfaE did not disrupt
translation of CFA/I proteins, nor biogenesis
of fimbriae, indicating that the loss of
binding behavior was not caused by loss of a
functional CfaE protein on the fimbriae, but
by localized areas of epitope disruption.
R181 appears to have a unique and
irreplaceable role in the formation of a
receptor-binding feature on CFA/I fimbriae.
The results also suggest that the CfaE tip
protein is a required binding factor in
CFA/I-mediated ETEC colonization, making
it an important vaccine antigen.
8. INITIAL CHARACTERIZATION OF
THE ESSENTIAL ACTIVITIES OF
SACCHAROMYCES CEREVISIAE Mtr4p
Bernstein, J., Patterson, D., Wilson, G.,
Toth, E
Morning; Oral Presentation; BRB 1-008
Processing of precursor RNA and
degradation of aberrant RNAs is the first
step in the expression of an accurate gene
product. Ribosomal, small nuclear and
small nucleolar RNAs are all processed
initially as long precursors, which must then
be trimmed to form functional RNAs. Any
byproducts of this trimming as well as any
defective RNAs must be rapidly degraded.
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This process is completed by the 3’→5’
single stranded exonucleolytic RNA
degradation machinery consists of an
exonuclease complex called the exosome
and the helicase Mtr4p. Mtr4p is a critical
partner of the exosome that presumably
maintains the momentum of the
exonucleolytic decay/processing by
removing secondary structures of the target
RNAs. We have shown that Mtr4p is in fact
a bona fide helicase with 3’→5’ polarity and
this activity is dependent on hydrolysis of
(d)ATP. Our studies also examined the
RNA binding parameters of Mtr4p showing
that Mtr4p binds single stranded RNA in a
length and nucleotide-dependent manner.
These studies also showed that Mtr4p has a
different mode of binding to polyA RNA
substrates. Taken together, these studies
offer an initial characterization of the
essential activities of Saccharomyces
cerevisiae Mtr4p and provide insight into
how it may function within the context of
the exosome machinery.
9. LYASE INHIBITOR/ANTIANDROGEN VN/124-1 INHIBITS
GROWTH OF ANDROGEN
INDEPENDENT PROSTATE CANCER
CELLS THROUGH
Robert D. Bruno, Tony D. Gover, Angelika
M. Burger, Angela M. Brodie, and Vincent
C.O. Njar
Morning; Oral Presentation; BRB 1-008
VN/124-1 is part of an emerging class of
prostate cancer (PC) therapeutics known as
lyase inhibitors. Based on surprising preclinical efficacy studies, we hypothesized
that VN/124-1 may have activity beyond the
androgen pathway, and therefore may have
efficacy against androgen independent PC
cells. To test this, we treated the androgen
independent prostate cancer cell lines PC3
and DU-145 with increasing concentrations
of VN/124-1 and found it inhibits the
growth of both cell lines in a dosedependent manner. Microarray analysis of
PC3 cells treated with VN/124-1 revealed
up-regulation of genes involved in cellular
stress and amino acid metabolism as well as
the down-regulation of genes involved in
DNA replication and cell cycle progression.
qRT-PCR analyses confirmed a strong upregulation of the endoplasmic reticulum
stress response (ERSR) related genes ATF4,
ASNS, and CHOP, as well as the calcium
binding protein S100P. The G1-cyclin,
cyclin E1, was also found to be significantly
down-regulated. Western blot analyses
revealed that treatment with VN/124-1
induces phosphorylation of eIF2alpha, the
up-regulation of the ERSR-induced protein
Bip, as well as the down-regulation of cyclin
D1, which was unchanged at the mRNA
level. The loss of cyclin D1 is therefore
likely due to translational inhibition via the
phosphorylation of eIF2alpha leading to the
arrest of cells in the G1-phase of the cell
cycle, a finding confirmed by flow
cytometry. Measurements intracellular
Ca2+ levels revealed that VN/124-1 induces
ERSR by depleting ER Ca2+ stores. Taken
together, this data suggests that VN/124-1
inhibits the growth of androgen independent
cell lines by disrupting ER Ca2+, resulting
in the induction of the ERSR.
10. THE ROLE OF SLP-76 IN CD4 T
CELL EFFECTOR FUNCTION AND
MEMORY GENERATION
Nicholas Bushar, Jonathan Maltzman,
Donna Farber
Morning; Oral Presentation; BRB 1-008
The linker/adapter protein SLP-76 is a
crucial mediator of native T cell signaling,
yet its role in effector and memory T cell
signaling remain unclear. In order to further
evaluate the role of SLP-76 in T cell
signaling, we used a conditional knock-out
mouse model containing floxed slp76 in
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combination with a cre-recombinase
inducible yfp reporter. CD4 T cells from
slp76 transgenic mice were activated in vitro
with anti-CD3/CD28 antibodies and treated
with TAT-fused cre recombinase to allow
for downregulation of SLP-76 and
expression of YFP. Down-regulation of
SLP-76 at 24 hours post-activation resulted
in an effector T cell phenotype in both SLP76 deleted and control cells in vitro. SLP-76
deleted effector cells were also capable of
IL-2 and IFNg production, suggesting that
SLP-76 dependent TCR signaling was no
longer required for effector function. To
evaluate memory generation, adoptive
transfers of SLP-76 deleted or control cells
were performed into RAG2-/- or NK and
CD8 T cell-depleted B6Ly5.1 hosts. In a
RAG2-/- host, SLP-76 deleted cells acquired
a CD44int, CD62Lhi central memory
phenotype, yet were hindered in their recall
capacity and long-term persistence
compared to control cells. In contrast,
adoptive transfer into NK and CD8 T celldepleted B6Ly5.1 hosts revealed that early
memory persistence of SLP-76 deleted cells
was comparable to that of control cells and
functional recall capacity of these cells
appeared augmented in the absence of SLP76. These results suggest a differential
requirement for SLP-76 signaling in effector
T cell function as well as in long-term
memory generation in lymphopenic vs.
intact mouse models.
11. IDENTIFICATION AND
CHARACTERIZATION OF A NUP98PHF23 FUSION GENE IN ACUTE
MYELOID LEUKEMIA
Jocelyn C. Reader, JoAnn S. Meekins, Ivana
Gojo, Yi Ning
Morning; Oral Presentation; BRB 1-008
NUP98 is a promiscuous fusion partner gene
linked to hematological malignancies. We
have identified a cryptic 11;17 translocation
in an acute myeloid leukemia (AML) patient
creating a novel in-frame fusion between
NUP98 exon 13 with PHF23 exon 4.
NUP98, which encodes a nucleoporin, has
been involved in more than 20 different
fusions. PHF23 is an uncharacterized gene
encoding a protein containing a plant
homeodomain (PHD) found in proteins that
mediate chromatin remodeling. The fusion
partners of NUP98 form two distinct groups:
homeobox (HOX) genes and non-homeobox
(non-HOX) genes. The non-HOX fusion
partner genes, which include NUP98PHF23, are diverse in function and are only
related by having the capacity to form
coiled-coil domain(s). The majority of the
research has focused on the mechanism of
NUP98-HOX genes in leukemogenesis;
therefore, we are interested in further
characterizing this novel non-HOX fusion
gene. We hypothesize that NUP98 fusion
genes act as aberrant transcription factors
that bind to DNA eventually leading to
transcriptional dysregulation. In order to test
if NUP98-PHF23 is able to confer an
oncogenic phenotype, we have cloned the
full length fusion gene into an expression
vector and expressed it in fibroblast cell line
NIH-3T3 and myeloid cell line K562 for
localization and differentiation analysis,
respectively. We have shown that NUP98PHF23 has nuclear localization in NIH-3T3
cells and can partially block TPA-induced
differentiation in K562 cells. Future
directions include gene expression studies,
identifying potential interacting co-factors
and determining whether NUP98-HOX and
NUP98-non-HOX have a shared mechanism
in leukemogenesis which, in turn, could lead
to new potential therapeutic targets.
12. WHOLE-GENOME ASSOCIATION
STUDY IN THE OLD ORDER AMISH
IDENTIFIES STK39 AS A NOVEL
HYPERTENSION SUSCEPTIBILITY
GENE
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Ying Wang, Patrick F. McArdle, Xialian
Shi, Evadnie Rampersaud, , Haiqing Shen,
Nanette I. Steinle, Braxton D. Mitchell,
Alan R. Shuldiner, Yen-Pei C. Chang
Morning; Oral Presentation; BRB 1-008
Hypertension (HTN) is a major risk factor
for cardiovascular and renal diseases.
However the specific genes that confer
predisposition to HTN remain elusive. We
conducted a genome-wide association study
of systolic blood pressure (SBP) and
diastolic blood pressure (DBP) by analyzing
93,087 SNPs in 551 subjects from the
Amish Family Diabetes Study (AFDS).
Twelve of the SNPs most strongly
associated with SBP and DBP were located
within the gene STK39 in 2 overlapping
linkage disequilibrium blocks. One
representative SNP from each block was
then genotyped in an expanded set of 743
nondiabetic AFDS subjects. Both SNPs
showed strong association with BP traits (pvalue <10-8 for SBP and 10-5 for DBP).
The at-risk allele was associated with an
estimated 5 and 2 mmHg increases in SBP
and DBP, respectively. As an independent
replication, we then analyzed SNPs from the
two associated blocks in a third independent
set of Amish (n=868) that were younger and
healthier than the AFDS population. Again,
we detected strong association, in the same
direction as seen in AFDS, between these
SNPs and baseline SBP levels. In addition,
analyses of BP traits by the Diabetes
Genetics Initiative
(http://www.broad.mit.edu/diabetes/scandin
avs/metatraits.html) also demonstrates
significant association between the same
STK39 SNPs and SBP level and HTN status
(p<0.02). STK39 encodes serine
threonine kinase 39 and is known to
stimulate the activity of Na+-K+-2Cl- cotransporter (NKCC1) in the distal nephron.
Furthermore, mutations in WNK1 and
WNK4, which phosphorylate and activate
NKCC1 through STK39, can cause a
monogenic form of HTN. In summary,
evidence from analyzing the Old Order
Amish as well as more outbred populations
suggested STK39 being a novel HTN
susceptibility gene.
13. PROSTAGLANDIN E2 RECEPTORS
MEDIATE PERINATAL
MASCULINIZATION OF BRAIN AND
BEHAVIOR
CL Wright, SR Burks, MM McCarthy
Morning; Oral Presentation; BRB 1-008
Prostaglandin E2 mediates (PGE2) the
organization of male rat sexual behavior and
preoptic area (POA) neuroanatomy during a
sensitive perinatal window. PGE2 is
upregulated in response to estradiol, which
is aromatized from testicular androgens and
initiates a two-fold increase in the density of
dendritic spines on POA neurons. PGE2
signaling is propagated through four Gcoupled protein receptors, called EP1-4. In
order to discover the mechanism by which
PGE2 elicits its profound permanent effects,
we first will determine which of the four
receptors binds to PGE2 and initiates the
signal transduction cascade resulting in
masculinization.
Real time PCR
analysis was used to assess the
developmental expression of EP1-4 mRNA
in the POA. Contrary to previous reports,
all four receptors are expressed. To identify
which receptors are sufficient to mediate the
effects of PGE2, we utilized specific
agonists from ONO pharmaceuticals for
each of the EP receptors and quantified: 1)
measures of adult male sexual behavior, 2)
neonatal and adult POA spinophilin levels as
a surrogate marker for dendritic spine
formation. To identify which EP receptors
are necessary for the masculinization of
brain and behavior, we used a combination
of antisense oligodeoxynucleotides against
EP receptors followed by PGE2
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administration on postnatal days 0 and 1.
This talk will discuss results implicating all
four receptors, yet converging on EP4 as
both necessary and sufficient for measures
of masculinization.
14. MICROMANIPULATED
STREPTOCOCCUS SPP.-VEILLONELLA
SPP. COMMUNITY FROM DENTAL
PLAQUE: INTEGRATED IN VIVO-IN
VITRO STUDY
Natalia I. Chalmers, Robert J. Palmer Jr. and
Paul E. Kolenbrander
Morning; Poster Presentation; Westminster
Hall
Oral biofilms are complex multispecies
communities that are important in the
development of the two most prevalent oral
diseases - dental caries and periodontal
disease. While their diversity has been
characterized extensively in health and
disease, little is known about the spatial
relationship between microorganisms and its
importance. We used a novel approach
integrating immunofluorescence and
fluorescence in situ hybridization to map the
spatial relationship between StreptococcusVeillonella spp. in an in vivo dental plaque.
Veillonella spp. cells almost exclusively are
in close proximity to receptor
polysaccharide (RPS)-bearing Streptococci.
RPS-bearing Streptococci are also in close
proximity to Streptococcus spp. cell and
other unidentified bacteria. Based on these
observations and the theoretical food-chain
relationship between Streptococcus and
Veillonella spp. we selected to
micromanipulate from the in vivo biofilms a
spatially defined community comprising of
anti-R1-veillonella reactive cell and RPSreactive cell. Upon further characterization
the community consists of: onle clone of
non-RPS-bearing Streptococcus cell, one
clone of RPS-bearing Streptococcus cell and
a R1-reactive Veillonella cell. Only the
Streptococcus isolates were cultivable for
further in vitro study. A phylogenic close
relative of the R1-reactive Veillonella was
selected to help the reconstruction of this
community in vitro. This integrated in vivoin vitro approach for the study of
micromanipulated Streptococcus-Veillonella
communities can serve as a new paradigm
for the study of oral biofilms and their
development, and for the advance of new
treatment and prevention strategies.
15. METABOTYPING BIOMARKER
CANDIDATES USING A TRANSGENIC
MOUSE MODEL OF ALZHEIMER'S
DISEASE
Laura Dosanjh, Michael Shapiro, Yuan Luo
Morning; Poster Presentation; Westminster
Hall
With the growing prevalence of Alzheimer’s
disease (AD) in the United States and with
an estimated impact of $160 billion in
annual health care by 2010, new treatments
for the disease are focusing on early
detection and prevention. Currently these
approaches are hindered by a lack of early
diagnostic biomarkers, and at this time,
clinical diagnosis can only be confirmed
postmortem. Metabolomic strategies
provide a comprehensive view of small
molecule metabolites known as a
“fingerprint”. Variations in this
“fingerprint” are commonly evaluated using
multivariate analysis techniques to provide
information about perturbations to the
system. We demonstrate that multivariate
analysis techniques can clearly distinguish
between wild type (C57Bl/6J) and double
transgenic (APPswe/PS1) mouse models of
Alzheimer’s disease as early as 3 months of
age, indicating that a “fingerprint” analysis
may provide an early diagnostic tool.
Mouse urine samples evaluated using partial
least squares discriminant analysis (PLSDA) show distinct differences between wild
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type and the AD model. Analysis of 18month-old transgenic mice as compared to
age-matched wild type (B6C3) has
implicated several candidate molecules in
disease development and progression.
Candidates for AD-related pathology
include several small molecule metabolites
involved in gluconeogenesis and the TCA
cycle. Furthermore, the metabolomic profile
of samples from a simple invertebrate model
of AD is evaluated by comparison to the
mouse model, and utilized in simple studies
to evaluate metabolomic findings. These
results implicate metabotyping as a novel
tool for identification of small molecules in
biological fluids of model animals that are
related to pathological events.
16. MOLECULAR MECHANISM OF
ROMK CHANNEL ENDOCYTOSIS
Liang Fang, Bo-Young Kim, James B.
Wade, and Paul A. Welling
Morning; Poster Presentation; Westminster
Hall
The density of ROMK channels in the
cortical collecting duct is physiologically
down regulated by clathrin-dependent
endocytosis in response to dietary potassium
deficiency. An aberrant over stimulation of
ROMK endocytosis likely contributes to the
hyperkalemia in pseudohypoaldosteronism
II. While an “NPXY” type signal in ROMK
is necessary for channel internalization, the
endocytotic sorting machinery that
recognizes the internalization signal has
been a mystery. Here we show that a
member of a new class of clathrin adaptors,
ARH, controls this activity. We found that
ARH in kidney is predominantly expressed
in the distal nephron, where it co-localizes
with ROMK in subapical and perinuclear
vesicular compartments. As measured by
cell surface biotinylation, co-expression of
ARH with the ROMK channel in COS-7 cell
led to a dramatic attenuation of ROMK cell
surface expression. These results were
corroborated by cell surface antibody
binding and luminometry studies. Swapping
the C-terminal domain of ROMK,
containing the NPXF motif, onto Kir2.1
channel conferred ARH-dependent
internalization on the chimera. Alanine
replacement of the NPNF tract in
N2.1/ROMK chimera increased cell surface
expression and rendered the channel
resistant to ARH, strongly suggesting the
NPXF internalization signal in ROMK is a
substrate for ARH interaction. A “pulldown” approach with recombinant Histagged ARH and GST-ROMKC protein
revealed that ARH directly interacts with the
ROMK C-terminus in a NPNF signal
dependent manner. Dominant-negative ARH
can also abrogate the effect that WNK1
increased ROMK endocytosis. Collectively,
these studies reveal that the “NPXY/F”-type
internalization signal in ROMK is
recognized by a member of a new class of
PTB-clathrin-adaptor molecules, ARH.
17. THE MOLECULAR MECHANISM
OF PKC MODULATION OF HERG1
POTASSIUM CHANNELS
Elena C. Gianulis and Matthew C. Trudeau
Morning; Poster Presentation; Westminster
Hall
Human ether-a-go-go-related gene 1
(HERG1) potassium (K+) channels underlie
the cardiac delayed-rectifier K+ current
(IKr), which is essential in repolarizing the
myocyte back to its resting membrane
potential. The closing rate (deactivation) of
HERG1 determines the amplitude of this
outward current. It has been shown that the
protein kinase C (PKC) activator OAG (1oleoyl 2-acetylglycerol) results in a decrease
in HERG1 current density and increase in
the rate of deactivation. Additionally,
mutation of 17 of the 18 putative PKC
phosphorylation sites results in a similar
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response to PKC activation to that of wild
type channels, whereas mutation of the 18th
site (Thr74) produces nonfunctional
channels. Furthermore, deletion of the Nterminus (Δ2-354), including Thr74,
attenuates the PKC effect. Therefore,
evidence suggests that Thr74 plays an
essential role in the modulation of PKC on
HERG1, yet previous groups have been
unable to fully characterize its role because
of the inability to make mutations at this
site. We have developed a unique method
for studying deactivation regulated by the
N-terminus by co-expressing a peptide
consisting of the most N-terminal amino
acids of the channel (1-135) with either WT
or Δ2-354 channels. With this, we are able
to make point mutations at the Thr74 site,
co-express with whole channels and analyze
the functional effects upon PKC activation,
all the while bypassing the major hurdle of
dominant-negative suppression by Thr74
mutants. Additionally, we are analyzing the
biochemical association of the 1-135 peptide
with the whole channel upon PKC
activation. We hypothesize that PKC acts on
the N-terminus to biochemically alter the
channel, and in turn alter the deactivation
kinetics of the channel.
motor cortex to probe and potentially
improve motor function in the stroke
population. Recently, impedance-controlled
robot training therapy has shown promise as
a novel approach to rehabilitation of stroke
survivors with chronic hemiparesis. These
robots can also be used to evaluate motor
deficits in stroke. We have therefore
conducted a pilot study to establish the
feasibility of robotic evaluation of TMSevoked arm movements.
The data
presented here define for the first time a map
of arm movements that can be elicited by
TMS using an upper extremity robot. We
analyzed the direction and magnitude of
movements elicited by surface stimulation
of motor cortex in healthy subjects. We
found that a wide range of movement maps
in the robotic environment are accessible by
TMS. These maps vary considerably by
patient, but within a patient they remain
fairly uniform. These findings enhance our
understanding of the neural bases for upper
extremity motor function and will hopefully
lead to more effective rehabilitation
paradigms in stroke patients.
18. MAGNETIC CORTICAL
STIMULATION AND ARM
MOVEMENTS IN A ROBOTIC
ENVIRONMENT
Jones-Lush, LM; Judkins, TN; Wittenberg,
GF.
Morning; Poster Presentation; Westminster
Hall
19. MICROARRAY ANALYSIS OF THE
OVERLAP BETWEEN GENES KNOWN
TO BE INDUCED BY HYPOXIA
AND/OR HYPOXIA-INDUCIBLE
FACTOR 1α (HIF-1α) AND GENES
RAPIDLY INDUCED BY ESTROGEN IN
RAT UTERINE EPITHELIAL CELLS.
Kristin Happ Molitoris, Armina A. Kazi,
& Robert D. Koos
Morning; Poster Presentation; Westminster
Hall
Stroke, the leading cause of adult disability
in the United States, often reduces upper
extremity motor function. The principal
output system of the brain for arm
movement is the primary motor cortex.
Transcranial magnetic stimulation (TMS) is
a method that can stimulate the primary
Estrogen is the master regulator of gene
transcription in the uterus, acting primarily
through its receptor, ERα. Prior work in our
laboratory identified hypoxia-inducible
factor 1α (HIF-1α) as a transcription factor
which, along with ERα, is necessary for
17β-estradiol (E2)-induced vascular
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endothelial growth factor (VEGF)
expression in the uterus (Kazi et al., 2005).
HIF-1α, normally present in the uterus at
low levels, is recruited to the VEGF
promoter by E2 (Kazi & Koos, 2007),
and regulates the transcription of over 50
genes; many of which are also induced by
E2 in the uterus. Therefore, we hypothesize
that E2-induced expression of many genes
will involve HIF-1α. To understand the
overlap between E2- and HIF-1-regulated
genes, we used a microarray specific for
genes known to be controlled by hypoxia
and/or HIF-1α (SuperArray Rat Hypoxia
Signaling Pathway Oligo GEArray) to
determine which genes are also induced by
E2 in the uterus. Of 114 genes represented,
11 were up-regulated by E2 by 1 and/or 4 h.
Increases in expression were detected for
several genes not previously reported to be
controlled by E2 in the uterus. Two of these
– the transcriptional regulators retinoic acid
receptor α (RARα) and inhibitor of DNA
binding 1 (Id-1) are of particular interest.
RARα was strongly up-regulated, which
suggests that it plays an important role in
E2-regulated gene transcription. Id-1 was
also up-regulated, and was recently shown
to play a role in angiogenesis. These
findings support our hypothesis that many
genes that play a role in cellular adaptations
to hypoxia are also required for E2-induced
endometrial growth. Supported by the
NIH/NHLBI-sponsored Institutional
Training Grant in Cardiac and Vascular Cell
Biology & the NICHD U54
Cooperative Centers Program.
20. A NOVEL MECHANISM FOR
ESTABLISHING SEX DIFFERENCES IN
THE BRAIN AND BEHAVIOR:
ESTRADIOL-ENHANCED GLUTAMATE
RELEASE.
Jaclyn M. Schwarz and Margaret M.
McCarthy
Morning; Poster Presentation; Westminster
Hall
Male and female rodent brains exhibit sex
differences in the neuronal morphology of
the medial basal hypothalamus (MBH) that
underlie sex-typic behaviors. The
differences between males and females are
established by estradiol during a critical
period of development. On the day of birth,
males have twice as many dendritic spines
on MBH neurons as females, and treatment
of females with estradiol increases dendritic
spines to levels seen in males within 6
hours. This increase requires activation of
AMPA and NMDA type glutamate
receptors. We hypothesize that estradiol
enhances glutamate release from
hypothalamic neurons to increase dendritic
spines and permanently differentiate brain
and behavior. To test this hypothesis,
presynaptic boutons from hypothalamic
cultures were labeled with the fluorescent
membrane dye, FM4-64, which measures
the rate of transmitter release as a function
of destaining following depolarization. We
found that 3 hours of estradiol treatment
significantly increased the probability of
transmitter release compared to controls.
We predict that the effect of estradiol or
NMDA on the sexually dimorphic dendritic
patterning of the neonatal MBH
permanently masculinizes adult sex
behavior. We determined that females
treated with NMDA (or estradiol)
postnatally showed low levels of lordosis, or
female sex behavior, however they showed
high levels of mounting behavior, or male
sex behavior, during separate behavioral
tests. We conclude that estradiol, via transsynaptic NMDA receptor activation,
permanently masculinizes adult sex behavior
via its neonatal effects on neuronal
morphology. These results lend insight into
novel mechanisms of hormone action in the
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brain as well as mechanisms establishing
sex differences in the brain.
21. THE EFFECTS OF LOCAL
ANESTHETICS ON MICROTENTACLE
PROTRUSIONS OF HUMAN
EPITHELIAL AND BREAST TUMOR
CELLS
Jennifer Yoon
Morning; Poster Presentation; Westminster
Hall
Detached breast tumor cells produce long,
dynamic microtubule protrusions that
promote reattachment of cells to one another
and to surfaces. These microtubule
protrusions have been termed tubulin
microtentacles (Tb-McTNs) due to their
mechanistic distinction from actin-based
filopodia/invadopodia and Tb-based cilia.
Mammary epithelial and breast tumor cell
McTNs are enriched with vimentin
intermediate filaments (Vim IF), and depend
on vim assembly for their extension. Within
McTNs, vim coaligns with a stable,
detyrosinated form of glu-tubulin, (Glu-Tb).
Given evidence that vim and Glu-Tb are
cross-linked by kinesin motor proteins, we
tested the role of kinesins in McTN
formation and function. The local
anesthetics Lidocaine (Lido) and Tetracaine
(Tet) have been shown to inhibit kinesins
during in vitro and single-molecule motility
assays. Treatment of human nontumorigenic
mammary epithelial cells and breast tumor
cell lines with Lido and Tet led to a rapid
collapse of vim filaments, detected by IF.
Live-cell fluorescence imaging also
demonstrated that Lido and Tet reduced the
motility of intracellular vesicles.
Measurements of cell viability with XTT or
apoptotic induction with PARP cleavage did
not show toxic effects at the concentrations
of Lido and Tet that affected cellular kinesin
activity. Lido and Tet also inhibited the
aggregation of detached epithelial and breast
tumor cells, a process that depends on TbMcTNs. In conclusion, the local anesthetics
Lido and Tet can reduce cellular kinesin
activity and inhibit the extension of TbMcTNs and their ability to promote cellular
aggregation. Our current data supports a
model in which the ability of Lido and Tet
to reduce the metastatic efficiency of
circulating tumor cells could result from
their inhibition of Tb-McTNs.
22. SYNTHESIS OF NIACIN PRODRUG
THAT TARGET HUMAN APICAL
SODIUM BILE ACID TRANSPORTER
(HASBT)
Xiaowan Zheng
Morning; Poster Presentation; Westminster
Hall
Purpose. hASBT is a potential candidate for
prodrug targeting to achieve a prolonged
release. Niacin is a highly effective
antihyperlipidemic agent. Clinical use of
niacin has been limited by its adverse
effects, particularly cutaneous flushing. The
pharmacokinetic and pharmacodynamic
profiles of the different niacin formulations
can be explained by the difference in their
dissolution/absorption rates, and metabolic
depositions, where slower availability of
niacin causes lower flushing side effect.
Design a prodrug of niacin by conjugating
with naturally occurring bile acid such as
chenodeoxycholic acid (CDCA) and
targeting hASBT could result in the slow
availability of niacin via sustained prodrug
hydrolysis. Method. Lysinechenodeoxycholate (lys-CDCA) was
prepared and then coupled to niacin. Identity
and purity of conjugates were characterized
by TLC, MS, and NMR techniques.
Compound inhibition of hASBT was
characterized via taurocholate (TCA) uptake
inhibition into hASBT-MDCK cells.
Results. The CDCA-lys-niacin conjugate
inhibited hASBT-mediated taurocholate
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uptake in a concentration-dependent
manner. Inhibition Ki was 12.87 (±2.6) µM,
which is in the same range of native bile
acids. Conclusion. The CDCA-lys-niacin
conjugate represents a potential prodrug of
niacin, which is designed to target hASBT
to achieve a sustained release for niacin.
23. MEMBRANE PROTRUSIONS IN
HUMAN MAMMARY TUMOR CELLS
ARE REGULATED BY THE
ANTAGONISM OF TUBULIN AND
ACTIN FILAMENT SYSTEMS
Eric M. Balzer, Rebecca A. WhippleBettes, Edward H. Cho, and Stuart S. Martin
Morning; Poster Presentation; Westminster
Hall
Breast tumor metastasis depends on
cytoskeletal alterations like those of the
epithelial-mesenchymal transition (EMT),
which is characterized in part by the
acquisition of dynamic cortical actin
structure. We have described highly
dynamic tubulin-based protrusions of the
plasma membrane, which are observed at
high frequency in tumor cell lines of great
metastatic potential. These tubulin
microtentacles (McTN) are infrequent in
untransformed cells and tumor lines of low
metastatic potential. Actin
depolymerization enhances McTN
formation, thus McTNs are structurally
distinct from filopodia, and other
microfilament processes. Jasplakinolide
(jas) forces microfilament disorder in vitro,
increasing McTN frequency in all cell lines
tested without reduced cell viability.
Propidium iodide was excluded from cells
with active McTNs, suggesting that jasinduced protrusions are produced by viable
cells. Immunofluorescent labeling revealed
that jas induces organization of α-tubulin
into outwardly projecting filaments,
extending from the cell periphery
concomitant with the collapse of
filamentous actin. Microtubule (MT)
stabilization augmented this response and
increased McTN frequency in suspended
cells. Aggregation assays demonstrated that
cells coalesced into large suspended
colonies more rapidly than their untreated
counterparts in a manner consistent with
McTN induction. These results describe a
novel antagonism between actin and tubulin
cytoskeletal networks in the context of
membrane protrusions; structures implicated
to be of potential relevance for endothelial
binding and extravasation of disseminated
tumor cells. Our findings advise caution
regarding the application of MT-stabilizing
agents in the context of transformed cells of
inherent actin disorder.
24. ALTERATIONS IN GABAERGIC
CORTICAL CIRCUITRY CHANGE
COGNITION
Gregory B Bissonette, Mihyun Bae, Tejas
Suresh, Geoffrey M Schoenbaum, Didier
Depireux, Elizabeth M Powell.
Morning; Poster Presentation; Westminster
Hall
The modern progression of transgenic
mouse models for human diseases presents
an opportunity for researchers to probe these
models for elements of human cognition.
Models involving cortical circuitry
alterations are especially of interest to
neuroscientists seeking to study the
neuroanatomical changes that persist in
certain diseases, such as Frontal Lobe
Epilepsy (FLE). We tested a mouse model
of defective frontal lobe inhibitory
GABAergic anatomy on cognitive tasks,
including a mouse reversal/set-shift test and
fear-conditioning paradigm. We used
several lines of mice: a mouse lacking the
urokinase plasminogen activator receptor
(uPAR) gene with a decreased GABA
interneuron phenotype, a hepatocyte growth
factor/scatter factor (HGF/SF)
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overexpressing mouse (Gfap-HGF), and a
cross between the uPAR-/- and the GfapHGF mice, in which the interneuron deficit
appears to be corrected. These lines were
tested on resident-intrude assay, open-field,
elevated plus maze, light-dark assay,
pentylenetetrazole (PTZ) seizure induction,
reversal/set-shift task and social interaction
paradigm. Electroencephalographical
(EEG) measurements were taken of
correlates of neural activity in samples of all
genotypes to observe baseline neural
activity. The uPAR null mice displayed
behavioral deficits in cued and contextual
extinction at different days, which was
sensitive to the developmental addition of
HGF/SF in the recovery mouse. These data
suggest that alterations in GABAergic
interneurons in the cerebral cortex impinge
upon consolidation of fear memories,
illuminating altered cortical to sub-cortical
circuitry notably deficits in prefrontal
mediated cognition.
25. THE 3D STRUCTURES OF CA(II)S100B BOUND TO SMALL
MOLECULES WITHIN THE TARGET
CLEFT OF S100B AS DETERMINED BY
X-RAY CRYSTALLOGRAPHY
Thomas H. Charpentier, Paul T. Wilder,
Melissa A. Liriano, Kristen M. Varney,
Alex D. MacKereel, Eric A. Toth, David J.
Weber
Morning; Poster Presentation; Westminster
Hall
Structural studies are part of a rational drug
design program underway to inhibit the
S100B-p53 interaction and restore p53
function in malignant melanoma. In a highthroughput competition assay with a peptide
from the C-terminus of p53 (p53367-393),
two small molecules, 132 and 279, were
found to bind S100B in a calcium-dependent
manner with dissociation constants of 1.3 ±
0.4 and 13.7 ± 3.2 µM, respectively. To
examine these complexes at atomic
resolution, both compounds were cocrystallized with Ca2+-S100B. Crystals of
Ca2+-S100B in complexes with 132 and
279 each belong to the C2221 space group,
and diffract x-rays to a limiting resolution of
2.10 Å and 1.98 Å, respectively. The
structures of 132 and 279 bound to S100B
were each solved and refined to give an
Rfree of 0.246 and 0.279, respectively.
Compound 279 binds into a hydrophobic
pocket of Ca2+-S100B comprising residues
in loop 2 (His42 and Phe43) termed the
“hinge region” as well as a nearby residue in
helix 4 (Phe87). Compound 132 binds in a
site that overlaps that observed for 279, and
is nearby residues in loop 2 and helix 4
(His42, Phe43, Leu44, Ala83, and Phe87).
The orientations of both 132 and 279, in
their respective binding sites, were
consistent with NMR data including
saturation transfer difference and 15N
backbone and 13C sidechain chemical shift
perturbations. These two X-ray structures
can now be used for developing new higher
affinity inhibitors of the S100B-p53
interaction.
26. DIFFERENTIAL GAMMA-TUBULIN
EXPRESSION IN METASTATIC
BREAST TUMOR CELL LINES
Edward H. Cho, Rebecca A. Whipple
Bettes, Michael A. Matrone, Eric M. Balzer,
Jennifer R. Yoon, Stuart S. Martin
Morning; Poster Presentation; Westminster
Hall
Gamma-tubulin is the major protein
involved in microtubule nucleation in
mammalian cells. In normal interphase
human cells, γ-tubulin is thought to be found
exclusively at the centrosome where, as part
of the γ-tubulin ring complex (γ-TuRC),
microtubule (MT) nucleation initiates. In
this study we sought to examine the role of
γ-TuRC proteins in metastatic breast cancer
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to begin to elucidate the role of MTs after
intravasation into the circulatory system.
Previous studies have reported that γ-tubulin
may exist outside of the centrosome, but the
reasons remain unclear. Our current studies
indicate that particular γ-TuRC proteins
differ in their phenotypic localization among
a panel of normal and tumorigenic human
breast cell lines of increasing metastatic
potential. Fluorescence analysis reveals an
increase of γ-tubulin in invasive breast
cancer cell lines over non-invasive cell lines.
Other γ-TuRC proteins, pericentrin and
ninein, were also shown to be differentially
expressed. MT nucleation along preexisting MTs has implications on current
breast cancer therapies that target
microtubule stabilization, such as paclitaxel.
However, MT disrupting drugs are often
ineffective against disseminated metastatic
tumor cells that remain dormant. Thus,
drugs like paclitaxel may potentially
promote microtubule growth in tumor cells
with cytoplasmic γ-tubulin. Further
investigation of the role of γ-TuRC proteins
could reveal more effective ways to target
the cytoskeleton of metastatic tumor cells to
prevent formation of secondary tumors
27. WHEAT GLIADIN ACTIVATES THE
IL23-TH17 INNATE IMMUNE
RESPONSE IN CELIAC DISEASE
Harris, Kristina, Fasano, Alessio and Mann,
Dean
Morning; Poster Presentation; Westminster
Hall
patients and HLA-DQ matched and
mismatched healthy controls. Peripheral
blood mononuclear cells (PBMC) from
treated CD patients, HLA-DQ2+ and DQ2controls were incubated with or without the
pepsin-trypsin digest of gliadin (PTG),
synthetic HLA-DQ2/8-binding epitopes of
a-gliadin, or b-glucan as a positive control
for 6, 24, 48, or 72h, and supernatants
harvested for cytokine analysis. PTG
induced the highest levels of IL-23 in CD
patients, intermediate levels in HLA-DQ2+
controls, and lowest levels in HLA-DQcontrols. The relative levels of other
cytokines that polarize Th17 cells (IL-1b,
IL-6, TNFa and CCL20) followed this same
pattern. Th1 cytokines IL-12p70 and IFNg
were not induced, further supporting the
IL23-Th17 axis. This response was only
generated with PTG and b-glucan, and not
HLA-DQ2/8-binding epitopes of a-gliadin.
As with PTG, the IL-23 response to bglucan was augmented in HLA-DQ2+
controls. These results demonstrate that
enzymatically digested gliadin activates the
IL23-Th17 pathway, and strongly advocate
involvement of this pathway in the
pathogenesis of CD. In addition, PBMC
from healthy controls with the disease
associated alleles had a greater capacity to
produce these cytokines than controls
without this genotype, indicating that the
high risk alleles and/or linked genes and
their products may function in the innate as
well as in the adaptive immune response in
this disease.
Celiac disease (CD) is an autoimmune
disease prevalent in 1% of the general
population. CD is unique because genetic
(HLA-DQ2/DQ8 alleles) and etiologic
factors (dietary glutens) for susceptibility
are known. Since the IL23-Th17 pathway
has recently replaced the IL12-Th1 axis in
autoimmunity, we evaluated the IL23-Th17
innate response to wheat gliadin in CD
28. MODULATION OF NATURAL
KILLER CELL ACTIVITIES BY
DECREASED COX-2 PATHWAY
METABOLISM AND EP RECEPTOR
SIGNALING
Dawn M. Holt, Namita Kundu, Xinrong Ma,
Amy M. Fulton
Morning; Poster Presentation; Westminster
Hall
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Breast malignancies often have high levels
of Cox-2. The Cox-2 product prostaglandin
E2 (PGE2) contributes to the high metastatic
capacity of breast tumors. Our published
data indicates that inhibiting PGE2
production or signaling abates metastasis.
In order to better understand the
mechanisms by which inhibiting PGE2
production or signaling reduces metastatic
disease, we focused on the role of Coxinhibitors and PGE2 antagonists in
activating immune defense. It is known that
Natural Killer (NK) cell function is
compromised by PGE2, but very little is
known about the mechanism by which
PGE2 affects NK effector activity. NK
effector function is regulated by complex
interactions of receptors expressed on NK
cells and ligands expressed on target cells.
Both stimulatory and inhibitory signals are
delivered through these receptor-ligand
interactions. Our novel findings show that
NK cells express all of the known PGE2
receptors (1-4). Preliminary data shows that
the NK-EP receptor expression pattern
changes during progressive tumor growth.
We then explored whether the receptors
could be classified as activating or
inhibitory receptors. Antagonism of EP
receptors on NK cells alters NK mediated
lysis and migratory ability. These results
support a mechanism whereby decreased
PGE2 synthesis or receptor-mediated
signaling enables NK cells to limit tumor
metastasis.
29. THE MICROTUBULE ASSOCIATED
PROTEIN, TAU, ALTERS
MICROTENTACLE FORMATION IN
DETACHED BREAST TUMOR CELL
LINES
Michael A. Matrone, Rebecca WhippleBettes, Edward H. Cho, Eric M. Balzer,
Jennifer R. Yoon, Stuart S. Martin
Morning; Poster Presentation; Westminster
Hall
Sensitivity of breast cancer to chemotherapy
is a concern for patients. Though adjuvant
treatments increase the rates of disease-free
survival, there remains variability in
sensitivities. In response, studies have been
undertaken to discover predictive markers of
breast cancer chemotherapy response. One
marker is the microtubule (MT)-associated
protein (MAP), tau. Tau is a neuronal MAP
that stabilizes and promotes polymerization
of MTs. Tau expression directly correlates
with taxol sensitivity and inversely
correlates with patient outcome.
Specifically, patients with pathologic
complete response from taxol had sensitive
tumors with low tau expression. In contrast,
patients with residual disease to taxolcontaining chemotherapy possessed resistant
tumors with high tau expression. The
mechanism for this is the competition of tau
and taxol for the same site on the MT. Our
research focuses on microtentacles that are
implicated in binding of circulating tumor
cells during extravasation. We have shown
that microtentacles, enriched in tubulin and
vimentin, facilitate the reattachment of
suspended cells. This trait is enhanced in
cells with a compromised actin cortex. In
breast tumor cell lines, those expressing
high levels of tau showed high microtentacle
formation upon suspension and actin
disruption. Exogenous expression of tau in
cell lines with low microtentacle frequency
increased microtentacle formation upon
actin disruption and suspension. In addition,
in cell lines with low or with high
microtentacle formation, tau expression
altered microtentacle morphology upon
suspension, inducing long, thick, and rigid
microtentacles, regardless of actin
organization. This indicates a potential
mechanism by which tau expression can
influence metastasis of breast tumor cells.
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30. Polymer-Peptide Conjugate for
Monitoring Cancer Targeted Drug Delivery
B. Zarabi, M. Bourgman, and H. Ghandehari
Morning; Poster Presentation; Westminster
Hall
Purpose: Synthesis, characterization and in
vitro evaluation of N-(2hydroxypropyl)methacrylamide (HPMA)
copolymer-gadolinium (Gd) chelates with
and without cyclic peptide c(Arg-Gly-AspD-Phe-Lys) c(RGDfK) for magnetic
resonance imaging. Methods: HPMA
copolymers with and without RGDfK were
synthesized by free radical precipitation
copolymerization of HPMA,
methacryloylglycylglycyl-RGDfK (MAGG-RGDfK) and
aminopropylmethacrylamide-benzyl1,4,7,10 tetraazacyclododecane-1,4,7,10
tetraacetic acid (APMA-benzyl-DOTA).
Gd+3 was chelated to the polymeric
precursors. The conjugates were
characterized for DOTA, Gd , and RGDfK
contents, and molecular weight and
molecular weight distribution. In vitro
integrin-binding affinities and specificities
of polymeric conjugates were assessed via
displacement cell binding assays using 125Iechistatin as the integrin-specific
radioligand. Results: The content of RGDfK
in targeted conjugate was approximately
70% of feed content. The Gd content was
approximately 70% and 82% of DOTA
content respectively in targeted and nontargeted systems.The estimated weight
average molecular weight of the polymers
was 45 and 43 kDa with polydispersity
index of 1.5. The receptor-binding affinity
studies of polymeric conjugates were
performed using αvβ3-positive Human
Umbilical Vein Endothelial Cells
(HUVECs). Both polymer-peptide conjugate
and free peptide inhibited the binding of
125I-echistatin to αvβ33 integrin–positive
HUVECs. The average IC50 values for
targetable polymer and free peptide were
1503 and 1311 (nmol/L). No effective
inhibition was observed by non targetable
polymer. Conclusions: The preliminary
results show that HPMA copolymer Gd
conjugate can be used as targeting
biomolecules for development of diagnostic
and therapeutics.
31. CHRONIC HYPOXIA INCREASES
NITRIC OXIDE GENERATION FROM
INDUCIBLE NITRIC OXIDE SYNTHASE
(INOS) IN FETAL GUINEA PIG HEARTS
LaShauna Evans and Loren Thompson,
Ph.D.
Morning; Poster Presentation; Westminster
Hall
The leading cause of fetal morbidity and
mortality is intrauterine hypoxia. Nitric
oxide (NO) is important in the regulation of
cardiovascular function and derived from
nitric oxide synthase (NOS) isoforms,
neuronal (nNOS), endothelial (eNOS), and
inducible (iNOS). Previous data has shown
that intrauterine hypoxia increased iNOS
expression and NO production in fetal
guinea pig ventricles. L-NIL (L-N6-(1Iminoethyl)-Lysine), a selective iNOS
inhibitor, was used to test the hypothesis that
iNOS-derived NO is linked to the hypoxiainduced upregulation of NO. Pregnant
guinea pigs were exposed to room air
(21%O2) or 10.5%O2 in a hypoxic chamber
14 days prior to term (term=65d). L-NIL
was administered to pregnant normoxic and
hypoxic mothers via their drinking water at
a dose of 1-2mg/kg/d for 10 days. At ~60d
of gestation, pregnant sows were
anesthetized and near term fetuses removed.
The hearts of the fetal pups were excised,
weighed, and normalized to their body
weights. Fetal ventricles were frozen in
liquid N2 and stored in -80oC. Total NO
product (NO2- and NO3-) of normoxic
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(n=4), hypoxic (n=5), hypoxic w/ L-NIL
(n=4) heart tissue was quantified. Hypoxia
increased NOx levels (68.4 pmoles/mg);
however L-NIL treated hypoxic hearts (29
pmoles/mg) significantly inhibited NOx
levels 58%. L-NIL inhibits iNOS derived
NO generation in the hypoxic fetal guinea
pig heart. Previous data from our lab
showed iNOS significantly increased, eNOS
decreased, and no change in nNOS levels.
L-NIL inhibition of iNOS-derived NO
supports the hypothesis that the hypoxia
induced NO pathway is mediated by iNOS.
More studies are needed to determine the
involvement of iNOS in the adaptive
response of the fetal guinea pig heart during
intrauterine hypoxic stress.
32. THE EFFECT OF VOLUNTEER
STUDY-DERIVED ACTUATION
PARAMETERS ON SPRAYED DROPLET
SIZE
Wenchi Hsu, Diane Doughty, Richard Dalby
Morning; Poster Presentation; Westminster
Hall
Nasal spray pumps are typically used to
deliver local treatment for nasal congestion
associated with allergies and colds. Users
must manually actuate nasal spray pumps to
release a mist containing medication. Due
to the manual actuation of nasal spray
pumps, inter-user actuation variability
exists, which can potentially affect
performance metrics. This study focuses on
the effect of volunteer study-derived
actuation parameters on the sprayed droplet
size and droplet size distribution from nasal
spray pumps. The Malvern Mastersizer S
was used in conjunction with automated
force-controlled and velocity-controlled
actuators to determine the volume median
diameter (Dv50) of nasal spray droplets in
the fully developed plume phase. The
automated actuators were programmed with
actuation force, force rise time, force hold
time, force fall time, compression velocity,
velocity hold time, and release velocity
values derived from a previously conducted
20 volunteer study. Nine studies were
conducted, with the first study utilizing the
global mean parameters derived from the
volunteer study. In each subsequent study
one parameter (e.g., actuation force) was
changed to either ± 2 standard deviations
(±2SD) from its mean parameter while all
the other parameters (e.g., force rise, hold,
fall times) were held constant at the mean.
Statistical analysis (p value < .05) showed
that the Dv50 values from the -2SD of the
mean force (47.4±0.058 µm), +2SD of the
force rise time (45.4±0.569 µm), and +2SD
of the force fall time (36.2±0.751 µm) were
each significantly different than the global
Dv50 obtained from the mean parameters
(33.9±0.964 µm). No other parameters had
a significant effect on the Dv50.
33. Probing Protein Interactions and
Elucidating the Catalytic Mechanism of
Ape1
Brittney Manvilla and Dr. Alex Drohat
Morning; Poster Presentation; Westminster
Hall
Damage to bases of DNA by oxidation,
alkylation, and deamination is repaired
through the base excision repair (BER)
pathway. An important step in this pathway
involves the apurinic/apyrimidinic (AP)
endonuclease 1 (Ape1) multi-functional
enzyme which cleaves the phosphodiester
backbone at AP sites as well as associating
with several BER proteins including pol?
and XRCCI. In addition to its cleavage
activity, Ape1 has inherent redox
capabilities which stimulate DNA binding of
several transcriptional factors such as AP-1
(Fos/Jun), HIF-1?, NF-?B, PAX, HLF, and
p53. The numerous associations and
functions of Ape1 and its high level of
expression in certain cancers have led to
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substantial research on the enzyme
concerning its catalytic mechanism and
specific protein-protein interacting domains.
In particular, our goals are to 1) investigate
protein-protein and protein-DNA
interactions of Ape1 using nuclear magnetic
resonance (NMR) spectroscopy, 2) elucidate
the catalytic mechanism of Ape1 using
transient- and steady-state kinetics and
equilibrium binding experiments, and 3)
develop inhibitors which disrupt the
interaction between Ape1 and its associated
BER proteins by chemical shift perturbation
mapping via NMR spectroscopy. These
investigations will enhance the overall
understanding of Ape1 by elucidating its
catalytic mechanism and its specific proteinprotein or protein-DNA interactions. In
combination, these studies will facilitate the
development of high-affinity therapeutic
inhibitors which may be useful for
restricting tumor cell proliferation in
specific cancer lines.
34. HEME CYTOPLASMIC BINDING
PROTEIN PHUS IS REQUIRED FOR
HEME UPTAKE IN PSEUDOMONAS
AERUGINOSA
Maura O'Neill and Angela Wilks
Morning; Poster Presentation; Westminster
Hall
HEME CYTOPLASMIC BINDING
PROTEIN PHUS IS REQUIRED FOR
HEME UPTAKE IN PSEUDOMONAS
AERUGINOSA Maura O’Neill and
Angela Wilks, Department of
Pharmaceutical Sciences, School of
Pharmacy, University of Maryland,
Baltimore Iron is an essential element for
the survival and virulence of bacteria. The
primary source of iron available to the
invading pathogen is in the form of heme,
which is sequestered in various heme
proteins within the host. Bacteria have
evolved sophisticated receptor mediated
heme uptake systems to acquire heme
directly from host heme containing proteins.
PhuS is a cytoplasmic binding protein (CBP)
in Pseudomonas aeruginosa which is
required for the efficient utilization of heme
as an iron source. The CBP has been shown
to traffick heme to the iron-regulated heme
oxygenase (paHO) which enzymatically
degrades the heme to release iron, biliverdin
and carbon monoxide. A phuS knockout
mutant was constructed to better understand
the protein’s role in heme trafficking. When
the phuS knockout was grown in LB media
it prematurely produced a blue-green
pigment which was determined to be
pyocyanin. Growth studies were performed
to compare the knockout strain with a phuS
complemented strain. Spectrometric
analysis revealed that pyocyanin production
was delayed in the phuS complement,
suggesting efficient heme transport. These
results further confirm the importance of
PhuS in heme trafficking and efficient heme
utilization. The phenomenon of premature
pyocyanin production will be used for high
throughput screens of PhuS mutants which
disrupt the transfer of heme to paHO.
35. THE ROLE OF THE BETA 1,2ADRENERGIC RECEPTOR SNPS IN THE
TREATMENT OF HEART FAILURE
WITH BETA-BLOCKERS
Hobart Rogers, Tom Dowling, Shawn
Robinson, Steve Gottlieb, Steve Liggett
Morning; Poster Presentation; Westminster
Hall
Beta-blockers are a first-line therapy for the
treatment of heart failure, however there is a
large variability in patient response. Recent
evidence suggests that differential response
to beta-blockade may be due in part to
genetic variability. Common SNPs for β1AR (codons 49 and 389) and β2-AR (codons
16 and 27) have been previously identified
and linked to significant differences in
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19
receptor expression and function in
experimental models, however the clinical
implications of these differences are still
unknown. To evaluate these clinical
implications, 180 NYHA class II-III heart
failure patients taking maximal doses of
beta-blocker (carvedilol or metoprolol) will
be enrolled from University of Maryland,
Heart failure clinic. Heart rate will be
measured at rest and immediately following
a 6-minute walk test. Patients will submit
blood samples to determine plasma betablocker concentrations and genotype at the
β1,2-AR SNPs. Currently, 43 patients (38
male, 5 female) have been enrolled in this
study. Sixteen patients have been genotyped
for β1,2-AR SNPs. Change in heart rate
from rest following the 6-minute walk test
was (27±14 and 22±10 b.p.m for the Arg389
homozygotes (n=10) and the Gly389
carriers (n=6), respectively (p = 0.47)). A
trend of lower resting heart rate in the
Arg389 homozygotes (67±12 b.p.m)
compared to the Gly389 carriers (77±4
b.p.m.) was observed (p = 0.07).
36. EFFECT OF VESTIBULAR
REHABILITATION ON PASSIVE
DYNAMIC VISUAL ACUITY
Matthew Scherer, PT, Americo A
Migliaccio, PhD Michael C Schubert PhD,
PT
Morning; Poster Presentation; Westminster
Hall
Computerized dynamic visual acuity (DVA)
during passive head impulses is a functional
measure of gaze stability and has been
shown to identify semicircular canal
hypofunction. Active DVA has been shown
to improve with gaze stabilization exercises.
We sought to determine whether DVA
during passive head impulses (pDVA)
would also improve following vestibular
rehabilitation (VR) in patients with
unilateral (UVH) and bilateral (BVH)
vestibular hypofunction. VR consisted of
gaze and gait stabilization exercises done as
a home exercise program. When DVA
improved for active head rotations, the post
pDVA measure was administered. We used
scleral search coil technique to characterize
the angular vestibulo-ocular reflex (aVOR)
gain and other eye responses. Mean duration
of VR was 66 ± 24 days, over a total of 5 ±
1.4 outpatient visits. Two of three subjects
showed improvements in pDVA with a
mean reduction of 43% (LogMAR 0.58 to
0.398 and 0.92 to 0.40). However, aVOR
gain increased only in the former (0.53 to
0.75, p=4.4E-8). Each subject used
compensatory saccades (CS) in the direction
of the deficient aVOR for ipsilesional head
rotations. Position (p = 0.08) and velocity
(p = 0.07) of the CS trended downward for
ipsilesional head impulses. Slow phase Eye
Velocity (SPEV) latencies decreased
significantly in the subject with BVH ( L
“ipsi” 28.6 ms to 13.1ms, p<0.00003; R
“contra” 12.14 ms to 7.23 ms, p<0.003).
CS frequency was reduced (Table 2) with a
corresponding decrease in the ratio of CS to
head rotations post participation in the gaze
stability protocol. Our data suggest VR can
improve DVA during passive head impulses,
in some individuals.
37. ANALYSIS OF H.PYLORI FUR: A
NEW PARADIGM FOR DNA
RECOGNITION
Abby West, Dr. Ronny Dosanjh, Dr. Sarah
Michel
Morning; Poster Presentation; Westminster
Hall
Analysis of H. pylori Fur: A new paradigm
for DNA recognition HPFur is a metal
responsive transcription factor found in the
virulent pathogen H. pylori where it
regulates expression of multiple genes
involved in iron homeostasis. HPFur has
two metal binding domains one of which is
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thought to require iron to function. HPFur
recognizes two types of DNA sequences; the
“Fur Box” and the “Pfr Box”. Fur binds the
“Fur box” under iron rich conditions to
repress iron acquisition and binds the “Pfr
box” under iron deplete conditions to
stimulate expression of iron storage
proteins. This protein is unique in that it can
act as both an activator and repressor of
transcription and it can bind DNA in both its
iron bound and unbound forms. Although
there are hypotheses on the metal content of
the protein; neither the nature of the metal
ions that bind HPFur nor the HPFur DNA
binding properties have been studied. We
have over expressed and purified HPFur and
performed biophysical characterization of
the protein. Circular Dichroism(CD) studies
have shown a secondary structure which is
52% alpha-helical. Thermal Denaturation
studies of HPFur under three conditions –
holoHPFur, holoHPFur + EDTA and
holoHPFur + Zn(1equivalent) were carried
out to assess how metal content affects
protein stability. Initial crystals of HPFur
have also been achieved. Current work
focuses on the identification of metal
content and DNA binding properties of
HPFur. HPFur also engages in crosstalk
with another H. pylori metallo-regulatory
protein HPNikR. Studies probing HPNikR
/DNA interactions will also be presented.
38. THE ARE-BINDING PROTEIN,
TRISTETRAPROLIN, IS
DIFFERENTALLY EXPRESSED IN
MANY CANCERS LEADING TO
ALTERED TUMORGENIC
PHENOTYPES
Sarah E. Brennan and Gerald M. Wilson
Morning; Oral Presentation; SSW/Law
Building 302
Stability of many messenger RNAs is
influenced by the presence of AU-rich
elements (AREs) within their 3’ untranslated
regions. Many of these transcripts encode
factors involved in tumor progression such
as pro-angiogenic factors, cell cycle
regulators, and inflammatory mediators.
The ARE-binding protein tristetraprolin
(TTP) targets mRNAs containing AREs for
rapid turnover, suggesting that the
expression and/or function of TTP may be
coupled to tumor aggressiveness. Using
cDNA arrays we revealed that TTP mRNA
levels were repressed in 100 out of 155
sample pairs across tissue types, as well as
in 30 different cancer cell lines as compared
to normal parental tissue. Restoration of
TTP expression in HeLa cells correlates
with decreased proliferation, increased
sensitivity to apoptotic stimuli, and
diminished expression of vascular
endothelial growth factor (VEGF) mRNA.
Mouse embryonic fibroblasts (MEFs) from
TTP knockout mice demonstrate different
effects of TTP expression, including
increased proliferation and decreased
sensitivity to apoptotic stimuli. Similar to
the HeLa cell model however, TTP
expression in MEFs decreased expression of
VEGF mRNA. Bioinformatic analyses of
gene chip studies shows that tumor
progression across different grades of breast
cancer is accompanied by repression of TTP
mRNA levels, and that loss of TTP in breast
cancer correlates with increased VEGF
mRNA. Gene chip studies of prostate
cancer show that TTP expression is similarly
decreased as tumors become metastatic, but
is not inversely correlated with VEGF
expression. Taken together, these data
suggest that loss of TTP expression may
alter cellular phenotypes to enhance tumor
progression, and that the mechanism of TTP
action may vary according to the tissue
source and tumor stage.
39. INFLUENCE OF TLR
ENGAGEMENT DURING EARLY
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PRIMING EVENTS ON PROTECTIVE
CAPACITIES OF CD4 T CELLS
Smita S. Chandran, John R. Teijaro,
Matthew Fenton, Donna L. Farber
Afternoon; Oral Presentation; SSW/Law
Building 302
Toll-like receptors (TLR) comprise a family
of pattern recognition receptors that
recognize pathogen-associated motifs, and
trigger antigen-presenting cell (APC)
activation for priming CD4 T cells. We
hypothesized that CD4 T cell responses
could be optimized by targeting engagement
of specific TLR during priming. We used an
in vivo system in which HA-specific or
OVA-specific CD4 T cells are CFSE
labeled, adoptively transferred into BALB/c
hosts, and subsequently primed with
antigenic peptide in the presence/absence of
agonists for TLR2 (Pam3Cys), TLR3
(polyI:C) or TLR4 (lipopolysaccharide).
CD4 T cells were harvested 1-2 weeks postpriming to monitor expansion, functional
capacity and protective responses against
PR8 Influenza challenge. Transferred CD4
T cells underwent robust antigen-driven
proliferation and expansion when primed
with both peptide and TLR agonist
compared to peptide alone. Pam3Cysmediated priming resulted in significantly
expanded populations with high levels of
IL-2 production, whereas TLR3 and TLR4
engagement resulted in predominant IFN-?
production with low IL-2 production. In
order to study the protective capacity of the
differentially primed CD4 T cells, we
challenged mice to Influenza virus. LPSprimed CD4 T cells afforded better
protection in terms of lung function and
viral load compared to P3C-primed CD4 T
cells. This suggests that a combination of
antigen-specific cell numbers and its
functional capacity at the site of infection
would dictate the protective capacities of
differentially primed CD4 T cell
populations. Thus, targeting TLR during
early priming could help design vaccines
that can manipulate the functional,
migratory and proliferative capacities in
order to afford optimal protection.
40. PROSTAGLANDINS AND
ESTRADIOL REDUCE DENDRITIC
SPINES IN THE
SL Dean, DL Krebs-Kraft, MM McCarthy
Afternoon; Oral Presentation; SSW/Law
Building 302
Prostaglandins are best known as mediators
of fever and inflammation, but they also
play a role in the normal development of the
central nervous system. In the preoptic area,
prostaglandins act downstream of the steroid
hormone estradiol to increase dendritic
spines, ultimately playing a crucial role in
adult male sexual behavior. Although
several studies have shown prostaglandin
receptors are expressed in the developing
cerebellum, their role in synaptogenesis in
this region has not been previously explored.
We have found that prostaglandins and
estradiol decrease rather than increase
dendritic spines in the cerebellum during the
second week of development, and
preliminary results suggest that in this area
prostaglandins act upstream rather than
downstream of estradiol. The role of the
cerebellum in neurodevelopmental diseases
such as autism and schizophrenia has
recently been appreciated, and the risk of
both of these diseases is increased with early
fever and inflammation. Understanding the
role inflammatory mediators play in the
normal development of the cerebellum can
give us insight into the pathogenesis of these
diseases.
41. METHAMPHETAMINE
FACILITATES FEMALE SEXUAL
BEHAVIOR AND ACTIVATES KEY
MOTIVATIONAL NUCLEI
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22
Mary K. Holder*, Maria M. Hadjimarkou,
Susan L. Zup, Margaret M. McCarthy,
& Jessica A. Mong
Afternoon; Oral Presentation; SSW/Law
Building 302
These data suggest that METH
simultaneously activates reward pathways
and the neural circuitry regulating female
sex behavior, which may have important
consequence for women’s health.
Humans using methamphetamine (METH)
are reported to be hypersexual, with a
tendency to engage in risky sexual
behaviors. Previous studies in rats have
demonstrated that METH facilitates sexual
behavior in males; however, the effects of
METH on female sex behavior are largely
unknown. We hypothesized that METH
would facilitate both receptive and
proceptive aspects of female sexual behavior
in a rodent model. To test this hypothesis,
we measured the expression of sexual
behavior in hormonally manipulated females
receiving either METH or saline vehicle.
Overall, we found that in females primed
with both estradiol and progesterone, METH
treatment significantly increased the number
of proceptive events and the lordosis
amplitude. The METH-induced
enhancement of female sexual behavior was
much more pronounced in the proceptive
component than in the receptive one. Open
field tests revealed that METH did not affect
overall locomotion in any treatment group.
To test the hypothesis that METH treatment
resulted in direct activation of the neural
circuitry mediating female sexual behavior,
brains were collected from animals treated
as above and processed for FOS
immunocytochemistry. In the VMN, a key
regulatory site for female sex behavior,
METH significantly increased the
expression of FOS and in the presence of
hormones there was an even greater increase
in FOS expression. In the medial
amygdala, implicated in reward and
motivational behavior, METH treatment
resulted in a significant increase in FOS, and
in the presence of hormones there was an
even greater increase in FOS expression.
42. PRE-CLINICAL
PHARMACODYNAMICS AND
PHARMACOKINETICS OF VN/14-1 IN A
PROSTATE CANCER MODEL
Aakanksha Khandelwal, Lalji Gediya, Vijay
V. Upreti, Vincent C. O. Njar
Afternoon; Oral Presentation; SSW/Law
Building 302
VN/14-1 is a novel retinoic acid metabolism
blocking agent (RAMBA) in development
for the treatment of breast and prostate
cancer. The objective of this study was to
explore the effects of VN/14-1, in an in vitro
and in vivo model of prostate cancer.
Effects of VN/14-1 were studied in hormone
refractory human PC-3 prostate carcinoma
cells. VN/14-1 inhibited PC-3 cell viability
staining with γ-H2AX revealed that VN/141 induced DNA damage in these cells. In
vivo, VN/14-1 decreased tumor growth in a
dose dependent manner in male SCID mice
with PC-3 xenograft upon subcutaneous
(s.c) administration QD. A dose of 5 and 10
mg/kg resulted in a 33% and 50% decrease
in tumor volume, respectively. Based on
simulations with previously determined
pharmacokinetic (PK) parameters with s.c.
dosing, it was determined that a multiple
dosing regimen with a higher dose would be
more favorable. Absolute oral
bioavailability and PK of VN/14-1 was
investigated in carotid cannulated SD rats
upon a single oral (p.o.) or intravenous (i.v.)
dose of 20 mg/kg. VN/14-1 was rapidly
absorbed upon p.o. administration reaching
peak plasma concentration (Cmax) within
0.5 h. Oral bioavailability of VN/14-1 was
found to be 100%. Cmax obtained upon p.o.
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and i.v. dosing was 38.2 µg/mL (104.28
µM) and 107.3 µg/mL (292.93 µM),
respectively. VN/14-1 was rapidly
eliminated upon administration, displaying a
short elimination half life of 1.41 h and 0.98
h upon p.o. and i.v. administration,
respectively. Pharmacokinetic evaluation
showed a favorable PK profile for VN/14-1
with good oral absorption and a high oral
bioavailability indicating its potential as an
oral anticancer agent. Overall these results
support further development of VN/4-1.
43. EXTRACELLULAR LOOP 2 OF
HUMAN APICAL SODIUMDEPENDENT BILE ACID
TRANSPORTER (ASBT, SLC10A2)
CONTAINS STRUCTURALLY AND
FUNCTIONALLY IMPORTANT PRO187
AND ASN183 RESIDUES.
Chandra M. Khantwal and Peter W. Swaan
Afternoon; Oral Presentation; SSW/Law
Building 302
Purpose: This study aims to methodically
appraise the contribution of extracellular
loop 2 (EL2) of hASBT in forming the
putative bile acid binding site. hASBT is a
key component in the enterohepatic
recirculation of bile acids as well as a
pharmacological target for cholesterol
lowering therapy and prodrug approaches
for enhanced oral drug absorbtion.
Methods: Role of EL2 was investigated
using cysteine-scanning mutagenesis in
conjunction with the membraneimpermeant, sulfhydryl-specific reagents,
sodium methanethiosulfonate (MTSES) and
methanethiosulfonate bromide (MTSET).
All thirteen ASBT mutants were created
from a fully functional, MTS-resistant
C270A-ASBT template by successively
changing each residue along EL2 to a
cysteine. These single cysteine mutants were
then expressed in COS-1 cells and their
expression levels, transport activities,
sensitivities to MTS reagents were
determined. Results: Overall, cysteine
replacement was tolerated at charged and
polar residues except for mutants V182C
and N183C which showed reduced TCA
uptake whereas W186C, Q188C, K189C
and I192C mutants exhibited increased
function. P187 which is present midway on
EL2 showed reduced uptake. Cell surface
expression of hASBT was found to be
normal for all the mutants used in the study.
TCA uptake was significantly inhibited by
2.5 mM MTSES and 2.5 mM MTSET for
K185C, A190C and I192C. Interestingly,
residues showing MTS sensitivity were
found to be clustered along one face of the
putative alpha-helix. Conclusion: Our
results strongly suggest that EL2 is
relatively solvent accessible containing
residues that play an important role in ASBT
function. Supported by NIH RO1
DK061425
44. INTERACTION OF THE DNA
BINDING DOMAIN OF DNA LIGASE I
WITH PCNA
Wei Song, John Pascal, Tom Ellenberger
and Alan E. Tomkinson
Afternoon; Oral Presentation; SSW/Law
Building 302
DNA ligase I deficiency results in genetic
instability and predisposition to cancer. This
enzyme joins Okazaki fragments during
DNA replication and completes certain
excision repair pathways. The participation
of DNA ligase I in these transactions is
directed by physical and functional
interactions with proliferating cell nuclear
antigen (PCNA), a homotrimeric DNA
sliding clamp. A conserved PIP box at the
amino terminus of DNA ligase I plays a
major role in its physical interaction with
PCNA and is required for DNA ligase I
function in DNA repair and DNA replication
in vivo. Our studies revealed that the DNA
GRADUATE RESEARCH CONFERENCE
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24
binding domain (DBD), one of three
domains within the DNA ligase I catalytic
fragment, also shows interaction with
PCNA. Peptide competition assays show
that a 23 amino acid peptide corresponding
to the N-terminus of DNA ligase I that binds
to the inter-domain connector loop of PCNA
does not affect the interaction between the
DBD and PCNA. Interestingly, while full
length DNA ligase I binds with the same
efficiency to PCNA monomers and trimers,
the DBD preferentially interacts with the
trimer, suggesting that it may bind to the
interface formed between subunits in the
PCNA ring. In support of this idea, we show
that pre-incubation of the DBD with a
modified version of PCNA with an Nterminal protein kinase A site that is
adjacent to the subunit interfaces within the
PCNA homotrimer decreases PCNA
phosphorylation. The goal of these studies is
to define the orientation of the DNA ligase I
ring with respect to the PCNA ring and
provide insights into the mechanisms by
which DNA ligase I is converted from its
elongated structure in the absence of DNA
to the compact ring formed on nicked DNA.
45. Protein Kinase C Activation Stabilizes
LDL Receptor mRNA via Activation of
JNK in HepG2 Cells
Noelle B. Vargas and Gerald M. Wilson
Afternoon; Oral Presentation; SSW/Law
Building 302
Low density lipoprotein (LDL) is the most
abundant cholesterol transport vehicle in
plasma, and remains a major prognostic
indicator of atherosclerotic risk. Hepatic
LDL receptors are essential for limiting
circulating LDL levels, since cholesterol
internalized by the liver can be excreted via
conjugation to bile salts. The focus of this
study is to characterize post-transcriptional
mechanisms regulating hepatic expression
of LDL receptors. Previously, our lab has
shown that activation of the protein kinase C
pathway using the phorbol ester TPA
enhances LDL receptor expression in the
hepatoblastoma cell line HepG2, in part
through stabilization of LDL receptor
mRNA. In this study, we have found that
TPA-induced stabilization of receptor
mRNA is accompanied by activation of
several mitogen activated protein kinase
(MAPK) pathways in HepG2 cells. Using
multiplex quantitative real-time PCR, we
have measured the stability of endogenous
LDL receptor mRNA from actinomycin D
(actD) time courses following perturbation
of specific MAPK targets. Initial screens
with pharmacological inhibitors of specific
MAPK pathways indicated that TPAinduced stabilization of LDL receptor
mRNA requires the JNK pathway. An
essential role for JNK activation in
stabilization of receptor mRNA was further
confirmed by siRNA knockdown
experiments. Adenoviral transduction of a
constitutively active mutant of MKK7, the
JNK-activating kinase, further confirmed
that JNK activation was sufficient to
stabilize LDL receptor mRNA. Prolonged
induction of JNK activity increased the
steady-state levels of LDL receptor mRNA
and protein, suggesting that perturbation of
the hepatic JNK pathway may represent a
novel anti-atherosclerotic therapeutic target.
46. MOLECULAR MECHANISM FOR
MODULATION OF DEACTIVATION IN
THE HERG1a K+ CHANNEL
Ahleah S Gustina, Matthew C Trudeau
Afternoon; Poster Presentation; Westminster
Hall
The Human Ether-a-go-go Related Gene
(HERG) encodes a voltage-activated K+
channel which is a primary component of
the cardiac delayed rectifier K+ current
(IKr). Cardiac IKr helps to repolarize the
ventricular action potential by conducting an
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25
outward K+ current whose amplitude is
determined, in part, by the closing
(deactivation) rate of the channel. Deletion
of the HERG1a N-terminus region (amino
acids 2-354) leads to a channel (HERG
Ndel) with very rapid deactivation kinetics
compared to wild-type HERG1a channels.
Furthermore, oocytes coinjected with
cRNAs encoding HERG Ndel and the distal
135 amino acids of the N-terminus (HERG
NT) showed partial restoration of the slow
deactivation to the HERG Ndel channel, as
evidenced by a significant increase in the
time constant for deactivation from that of
the N-terminus deleted channels alone. This
is evidence that the HERG1a N-terminal
region interacts with the body of the
channels to modulate deactivation rate. To
investigate the N-terminal residues
necessary for interaction with the channel,
mutations were made in several amino acids
within the distal N-terminus. These
mutations led to loss of recovery when
coinjected with HERG Ndel. Also, when
one of these mutations was expressed in the
full length HERG1a channel, a speeding of
deactivation was noted, which could be
slowed by addition of HERG NT.
We are now seeking to determine the region
in the channel body that functions as the
binding site for the distal N-terminus.
Alanine mutations are being created in the
S4-S5 linker region and the upper S6 region
of the channel to determine which residues
reduce N-terminal interaction, as evidenced
by a change in channel deactivation rate.
47. Assessment of Hemiparetic Ankle
Movements Using an Impedance Controlled
Ankle Robot
Ira Khanna, Anindo Roy, Mija Lee and
Larry Forrester
Afternoon; Poster Presentation; Westminster
Hall
Hemiparesis after stroke often leads to
impaired ankle motor control that affects
gait function. Impedance controlled robotic
devices have been used successfully to
improve upper extremity motor function in
subjects with residual hemiparesis after
stroke [H. Krebs et al, J. NeuroEng and
Rehab, 1,5, 2004.]. A collaboration between
the Baltimore VA and MIT is now
underway to develop an impedance
controlled ankle robot (Anklebot) to pursue
similar therapies for lower extremity
hemiparesis. We recently reported results to
estimate passive ankle stiffness using the
Anklebot in healthy humans. Since the ankle
joint plays a significant role in locomotion,
it is imperative that accurate estimates of
ankle stiffness be quantified for
rehabilitation of gait. Coupled with human
ankle stiffness is the estimate of inherent
damping at the ankle. In this study, we
propose a method to estimate the intrinsic
damping utilizing the Anklebot as a
measuring tool. The initial estimates of
damping at the ankle joint can be compared
to previously published work to determine
accuracy. This initial research will help to
establish Anklebot control parameters
during assistive movements of the paretic
ankle during therapeutic exercise and
training.
48. ASSESSMENT OF NASAL SPRAY
DEPOSITION IN A NOSE MODEL
USING A COLORIMETRIC TECHNIQUE
Vipra Kundoor and Richeard N.Dalby
Afternoon; Poster Presentation; Westminster
Hall
Purpose. To develop an inexpensive and
uncomplicated colorimetric method to assess
the site of initial nasal spray deposition
within anatomically correct human nose
models. Methods. Several colorimetric
techniques to visualize the site of droplet
deposition were evaluated, culminating in
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26
the identification of Sargel® as a possible
indicator. Sargel® is a commercial water
level-indicating paste which turns from
white to purple on contact with water.
Changes in color were captured using a
digital camera under standardized
photographic conditions, and the images
were analyzed using Adobe® Photoshop.
Three commercially available nasal sprays
Afrin®, Ayr® and Zicam® were evaluated
in terms of their spray deposition area using
the Sargel® method. Results. There was a
definitive change from white to purple when
Sargel® came into contact with each
sprayed formulation. Conclusion. This
represents the basis of a simple and
inexpensive colorimetric method by which it
may be possible to assess the droplet
deposition of nasal sprays if a realistic,
transparent model becomes available. Even
in the absence of a “representative” nasal
model such methodology may be developed
to yield metrics on which in vitro
bioequivalence decisions could be based.
49. APPLICATION OF NEARINFRARED SPECTROSCOPY (NIRS) IN
PREDICTING THE POROSITY OF
ROLLER COMPACTION RIBBONS.
Han-Pin Lim, Raafat Fahmy, Stephen W.
Hoag
Afternoon; Poster Presentation; Westminster
Hall
Purpose: To use near-infrared spectroscopy
(NIRS) to evaluate the porosity of roller
compacted ribbons which were prepared
using different roller compactor (RC)
settings, different particle sizes and densities
of microcrystalline cellulose (MCC).
Methods: MCC of different particle sizes
and bulk densities was roller compacted at
various hydraulic pressures (HP), feed screw
speeds (FSS) and roller speeds (RS). The
NIR spectra were collected on both sides of
the ribbons. True densities (?true) of the raw
materials were determined using a helium
pycnometer and the envelope densities
(?envelope) of the ribbons were determined
using a fluid displacement pycnometer. The
porosity was calculated and the results were
used to correlate with NIR spectra using
multivariate analysis. Results: The porosity
decreased by 45% for Avicel® PH 101 and
PH 200 as the HP increased from 20 to 60
bar with FSS and RS held at 40 and 8 rpm,
respectively. When comparing MCC with
different particle sizes, the porosity of the
ribbons was similar at the same RC settings.
However, Avicel® PH 101 ribbons had
porosities of 43.6±1.2% while Avicel® PH
301 ribbons had porosities of 32.5±1.8% at
HP, FSS and RS of 60 bar, 20 and 8 rpm,
respectively; which were significantly
different from each other (p<0.05). The
NIR absorbance increased as the ribbon
porosity decreased. The correlation between
laboratory porosity data and NIR absorbance
spectra was good using partial least squares
regression (PLS), yielding a R2 value of
0.972, standard error of calibration (SEC) of
1.33%, and standard error cross validation
(SECV) of 1.77%. Conclusion: A PLS
calibration model using NIR spectra was
developed and allowed accurate detection of
porosity for different RC settings, different
particle sizes and densities of MCC.
50. DANTROLENE SODIUM LIMITS
THE NOVEL CA2+ ENTRY
MECHANISM, EXCITATION-COUPLED
CALCIUM ENTRY (ECCE), A POSSIBLE
CONTRIBUTING CAUSE OF
MALIGNANT HYPERTHERMIA CRISIS
Luke Michaelson, Dr. Chris Ward
Afternoon; Poster Presentation; Westminster
Hall
Malignant hyperthermia (MH) is a
pharmacogenetic pathology in susceptible
individuals who receive inhaled general
anesthetics or depolarizing muscle relaxants.
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The MH response is characterized by a
hypermetabolic crisis elicited by a sustained
increase of calcium (Ca2+ ) in skeletal
muscle cells. It is generally accepted that
mutations in the sarcoplasmic reticulum
(SR) calcium release channel Ryanodine
Receptor type 1 (RyR1) increase RyR1
opening in the presence of the agents which
trigger an MH episode. The most effective
current therapy to blunt an MH episode is
Dantrolene Sodium, a drug which has been
shown to bind to the RyR1, promoting
channel closing and thus inhibiting RyR1
dependent Ca2+ release. Recent work,
however, evaluating the therapeutic
concentration of Dantrolene needed to
inhibit the MH episode had led to the
hypothesis that Dantrolene may have other
cellular effects which also act to reverse the
MH crisis. In our current work, we explore
the effectiveness of Dantrolene sodium in
inhibiting a novel Ca2+ entry mechanism
coupled to membrane depolarization termed
excitation-coupled-calcium-entry (ECCE)
recently identified in skeletal myotubes.
Here we demonstrate a novel finding that
ECCE is operant in adult mammalian
skeletal muscle fibers and is inhibited by
Dantrolene. Furthermore, we demonstrate
that Dantrolene is effective in inhibiting an
exuberant ECCE response seen in
chemically modified RyR1. Based on
additional work in myotubes expressing
RyR1 containing known MH mutations, we
believe a novel action of Dantrolene in the
MH crisis is to inhibit ECCE related Ca2+
influx.
51. S100A1 BINDS THE CALMODULIN
BINDING SITE OF RYR1 AND
POSITIVELY REGULATES EC
COUPLING IN SKELETAL MUSCLE:
FUNCTIONAL STUDIES
Benjamin L Prosser, Nathan T Wright, Erick
O. Hernandez, David J Weber, Martin F
Schneider
Afternoon; Poster Presentation; Westminster
Hall
S100A1, a 21-kDaCa2+ binding protein, is
an enhancer of cardiac Ca2+ release and
contractility and a potential therapeutic
agent for the treatment of cardiomyopathy.
A role of S100A1 in skeletal muscle has
been less well defined. Additionally, the
precise molecular mechanism underlying
S100A1 modulation of SR Ca2+ release in
striated muscle has not been fully
elucidated. Here, utilizing a genetic
approach to knock out S100A1, we
demonstrate a direct physiological role of
S100A1 in skeletal muscle EC coupling.
We show that the absence of S100A1 leads
to decreased global Ca2+ release following
electrical excitation, and that adenoviral
delivery of S100A1 can rescue this Ca2+
signaling phenotype. Using high-speed
confocal microscopy we demonstrate with
high temporal resolution depressed
activation of SR Ca2+ release in S100A1-/muscle fibers. Through competition assays
with SR vesicles and tryptophan
fluorescence experiments we identify a
novel S100A1-binding site on RyR that is
conserved throughout striated muscle and
corresponds to a previously identified
calmodulin binding site. NMR spectroscopy
reveals that a 12-mer RyR peptide derived
from the CaM binding site binds within the
Ca2+ dependent hydrophobic pocket of
S100A1. Taken together, these data suggest
that S100A1 plays a significant role in EC
coupling in skeletal muscle, putatively
through specific interactions with the CaM
binding domain of RyR1. This warrants
further investigation into the use of S100A1
as a therapeutic target for the treatment of
both cardiac and skeletal myopathies.
52. INDUCTION OF APOPTOSIS BY
NOVEL SUBSTRATE SELECTIVE
EXTRACELLULAR SIGNAL-
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REGULATED KINASE (ERK)
INHIBITORS
Sarice R. Smith and Paul Shapiro
Afternoon; Poster Presentation; Westminster
Hall
The ERK proteins are potent mediators of
cell proliferation and survival. Unregulated
activation of the ERK proteins plays a role
in the progression of a variety of cancers.
Thus, targeted inhibition of ERK’s function
in promoting cell proliferation and survival
is viewed as a promising approach for anticancer therapy. Using in silico modeling,
we have recently developed small molecular
weight compounds that target ERK domains
involved in specific substrate interactions.
Compounds designed to target the common
docking (CD) domain on ERK2 were tested
for their ability to block anti-apoptotic
mechanisms involving ERK
phosphorylation of p90RSK-1, which
promotes cell survival by phosphorylating
and inactivating the pro-apoptotic protein
BAD. HeLa cells treated with 50 ?M of one
compound (termed 76) caused induction of
apoptotic signaling pathways as measured
by cleavage of poly (ADP-ribose)
polymerase (PARP), which was observed
within 3 hours. PARP cleavage induced by
76 required activation of the intrinsic
apoptotic pathway, specifically caspase 9
and caspase 3. Compound 76 inhibited
p90RSK-1 phosphorylation of BAD in a
manner that correlates with caspase
activation. Furthermore, inhibition of BAD
phosphorylation in the presence of
compound 76 was not due to off-target
effects on other pro-survival pathways.
These findings suggest that substrate
selective inhibition of ERK signaling
promotes apoptosis in transformed cells,
illustrating a novel approach to the
development of anti-cancer therapies.
(Supported by NIH Grant # CA120215)
53. SMALL MOLECULE INHIBITORS
AGAINST BCL6
Xiao Zhu, Gustavo F. Da Silva, Alex Ghetu,
Shijun, Zhong, Leandro Cerchietti, Marilyn
Matthews, Jose M. Polo, Andrew Coop,
Gilbert G. Prive, Ari Melnick, and
Alexander D. MacKerell, Jr.
Afternoon; Poster Presentation; Westminster
Hall
Oncogenic chromosomal translocation and
somatic mutations involving the BCL6 gene
is commonly observed in B-cell lymphomas
especially in diffuse large B-cell lymphoma
(DLBCL). The BCL6 gene expresses a
transcription factor that represses expression
of regulatory proteins in cell differentiation
and apoptosis. Therefore, BCL6 presents an
interesting target for rational drug design. A
computational three-dimensional (3-D)
database search was used to identify druglike compounds that bind to a subset of the
lateral binding groove on BCL6 to which
co-repressors are recruited. Based on the
structural and chemical environment of the
target binding groove, a preliminary search
of a library of more than 1 million
compounds produced a list of 50,000
compounds. In addition to the crystal
structure, two energetically favorable
conformations generated by molecular
dynamic (MD) simulations were subject to a
more rigorous screening step. Ten out of the
100 assayed compounds exhibited >20%
inhibition of BCL6BTB mediated
transcription repression at 50 µM
concentration. Similarity search of active
compounds yielded active compound 57-6
with improved affinity for BCL6.
Crystallographic analyses indicate direct
interactions of 57-6 with the originally
targeted binding groove. Further analyses
showed that compound 57-6 selectively
disrupts recruitment of co-repressors N-cor
and SMRT leading to reactivation of its
target genes in DLBCL and disruption of the
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ability of BCL6 to maintain survival and
proliferation in DLBCL cells. This
compound also showed anti-lymphoma
activity in mice without overt toxic effects.
Together, the in vitro and in vivo result
presented may contribute towards the
development of a novel anti-lymphoma drug
candidate.
54. A PHARMACOKINETIC ANALYSIS
OF UCN-01 AND THE EFFECTS OF AAG
(α1-ACID-GLYCOPROTEIN)
Charlene A. Baksh, Kenneth S. Bauer,
Martin Edelman
Afternoon; Poster Presentation; Westminster
Hall
UCN-01 (7-Hydroxystaurosporine) is a
protein kinase inhibitor that has been shown
to have 3 effects in tumor cells: (1) cellcycle arrest, (2) induction of apoptosis, and
(3) sensitization to DNA-damaging agents.
The purpose of this study was to determine
the pharmacokinetics of UCN-01 and the
influence of AAG on UCN-01 disposition.
UCN-01 was administered as a 3-hour
intravenous infusion to 21 patients in
combination with carboplatin during a Phase
I clinical trial in cancer patients with solid
tumors. Plasma concentrations of UCN-01
were determined using a previously
published reverse-phase HPLC assay
method. The pharmacokinetic parameters of
UCN-01 were established using a
compartmental modeling approach with
ADAPT II. A two compartment open linear
model best fit the UCN-01 concentrationtime data. The mean volume of distribution
for the central compartment (Vc) was found
to be 6.1±4.3L, and the Vp (volume of
distribution for the peripheral compartment)
resulted in a mean of 16.6±10.7L. The total
clearance (Clt) of UCN-01 was found to be
0.21±0.81L/hr. The mean half-life of the
distribution phase (t1/2?) was 3.4±7.0hr, and
the mean elimination phase half-life (t1/2?)
was determined to be 456±245hr. AAG
levels were found to be correlated with the
Vc (r2 =0.215). The pharmacokinetic
parameters for UCN-01 yielded a relatively
slow clearance and low volume of the
central compartment. The t1/2? was quite
large due to the extensive binding to AAG.
A correlation between Vc and AAG
exemplify the significance in the effect of
drug binding on the pharmacokinetics of
UCN-01, suggesting a need for a population
based assessment of the influence of AAG
as a predictor of UCN-01 pharmacokinetics.
55. USING CAENORHABDITIS
ELEGANS AS A MODEL TO SCREEN
NOVEL ERK2 INHIBITORS
Fengming Chen, Paul shapiro
Afternoon; Poster Presentation; Westminster
Hall
The extracellular signal-regulated kinase
proteins (ERKs) are very important in the
proliferation and survival of cancer cells.
Selective inhibition of ERK activity may be
a potential way to treat cancer associated
with ERK hyperactivation. Our previous
research has identified that several test
compounds that inhibit ERKs’ interactions
with downstream substrates involved in
cancer cell proliferation. In order to examine
the potency of ERK2 inhibitors in a complex
organism, we chose Caenorhabditis elegans
(C. elegans) as a research model. C. elegans
is a well characterized organism that is
inexpensive and easy to maintain in the
laboratory. More importantly, C. elegans has
the MPK-1 protein, which is homologous to
human ERK2, known to be required for
vulva formation and egg laying. In this
study, we describe the use of a C. elegans as
a drug screening model to evaluate the
effects of novel ERK inhibitory compounds.
Preincubation of C. elegans larvae with
several compounds before vulva formation
causes inhibition of egg laying. However,
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30
these compounds have no effect on life span
and show no toxicity in C.elegans indicating
that the compounds effects were specific to
egg laying. In addition, the transgenic strain
CL2070, which contains GFP transporter
controlled by the hsp-16-2 promoter, was
used to measure non-specific stress
responses induced by the test compounds.
The results reveal no HSP-16-2 induction
and that the compounds effects on egg
laying were not due to non-specific stress to
the organism. These data suggest that C.
elegans can be a model organism to identify
compounds which selectively inhibit ERK2
functions and may be the useful tool for
drug identification and development.
56. PREPARATION AND FUNCTIONAL
EVALUATION OF THEOPHYLLINE
MATRIX TABLETS PREPARED BY
ROLLER COMPACTION
Vivek S. Dave, Raafat Fahmy and Stephen
W. Hoag
Afternoon; Poster Presentation; Westminster
Hall
The effects of plasticizer content, roll
pressure and thermal treatment on the
properties of granules, the breaking force of
tablets and release of theophylline from
tablets were investigated. The powder blend
was roller compacted using a fixed roll-gap
of 1.5 mm, feed screw speed to roller speed
ratio of 5:1 and varying roll pressure from
40 to 140 bar in 20 bar increments. The
granules obtained were evaluated for
particle size distribution (sieving) and
flowability (Carr index). Granules, after
removing fines were compacted into tablets
(300 ± 5 mg). The tablets were thermally
treated at two different temperatures (60 and
75°C) for 5 hours. The tablets were
evaluated for breaking force and the
dissolution was carried out in accordance
with conventional method (USP apparatus
II) using distilled water as dissolution
medium. Roller compaction resulted in
significant increase in the mean particle size
of granules and improved the flowability of
the formulation (powder blend, CI=26-30%
and dry granules, CI=15-25). Breaking force
of tablets significantly increased with
increase in temperature and amount of
plasticizer. The release of theophylline was
unaffected by roll pressure for the tablets
prepared from formulation A with a slow
release (less than 60% theophylline released
at the end of 8 hrs). For tablets prepared
from formulation B theophylline release
decreased proportionately with increase in
temperature of thermal treatment with more
rapid release seen at higher roll pressure
(120 bar) compared to lower roll pressures
(40 bar). Roller compaction along with
thermal treatment and plasticizer content has
potential for development of sustained
release oral solid dosage forms.
57. In-vitro Studies on the Bioequivalence
in Nasal Sprays Containing Suspension
Formulations
Feiyan Jin and Richard N. Dalby
Afternoon; Poster Presentation; Westminster
Hall
Purpose: A FDA draft guidance
recommends that bioequivalence (BE) of
nasal spray products containing suspension
formulations be established by a
combination of clinical studies and in-vitro
tests including a finding of comparable
particle size distribution (PSD) for the drug
substance. Locally acting nasal solutions do
not necessitate a clinical comparison. To
support “equivalence” without a clinical
study, the drug absorption and cytotoxicity
profiles of suspension formulations were
studied using a cell-culture model. Methods:
Beclomethasone dipropionate (BDP) was
micronized and the resulting primary drug
particles were dispersed to prepare BDP
nasal suspensions. The PSDs of the
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31
micronized products and the droplet size
distribution (DSDs) of BDP suspension
formulations were determined. The Calu-3
cell line was grown to confluency on
Transwell at an air interface. BDP
suspension was pipetted onto the apical side
of the Transwell. Trans-Epithelial Electrical
Resistance (TEER) was measured to verify
the formation or post experimental integrity
of tight junction. Results: Laser diffraction
studies showed that the primary BDP
particles had volume median diameters
(Dv50) of 4.8, 2.7, 2.5, 2.0 and 1.7µm.
There were no significant differences
between the volume diameters of the
sprayed droplets of BDP suspensions. Calu3 cell monolayers incubated with BDP
suspensions indicated the suspension
formulations did not damage the cells and
the monolayer remained intact. Conclusions:
The sizes of primary drug particles in nasal
suspension formulations in the relevant
range did not affect the droplet size of the
resulting spray. Calu-3 cell line appears to
be a promising and robust in-vitro model to
study drug absorption and toxicity profiles
of nasal suspension products.
58. LOSS OF MET SIGNALING IN
EMBRYONIC POST-MITOTIC CELLS
ALTERS STRIATAL DEVELOPMENT
Gabriela J. Martins and Elizabeth M. Powell
Afternoon; Poster Presentation; Westminster
Hall
The striatum is composed of GABAergic
projection neurons and interneurons arising
from the embryonic ganglionic eminence
(GE). However, the mechanisms underlying
the generation of all the subtypes of neurons
and their assembly into a functional circuit
are poorly understood. In the current study,
we elucidate the role of the hepatocyte
growth factor/scatter factor (HGF/SF) in the
embryonic forebrain, specifically its role in
the development of the GABAergic neurons
populating the striatum. HGF/SF, when
bound to its receptor Met, induces a
signaling cascade that can act as a
chemoattractant, or a general promoter of
cell movement, proliferation, or
differentiation in neural tissues. To analyze
the importance of HGF/SF-Met signaling,
we have used a targeted conditional Met
knockout for the ventral telencephalon in
post-mitotic cells: where the floxed Met
allele (Metfx) is rendered null in areas of
expression of the Dlx5/6Cre transcription
factor (Metfx:Dlx5/6Cre). The neuronal
populations of the adult mouse striatum
were assessed for the GABAergic
development patterns as mediated by the
HGF/SF-Met system. Our data suggest that
Met is required in ventral telencephalic postmitotic cells for the proper development of
GABAergic neurons. However, the
cholinergic interneuron population (ChAT+)
of the striatum remained intact. These
altered expression patterns could lead to an
imbalance of striatal circuitry and thus be
implicated in various cognitive disorders.
Future studies will investigate the cognitive
and behavioral consequences of altering the
GABAergic system.
59. ROS AND CHEMOKINE RELEASE
IN A549 CELLS IN RESPONSE TO Fe
AND Se EXPOSURE
Potnis, P.A., Squibb, K.S., and Elnabawi, A.
Afternoon; Poster Presentation; Westminster
Hall
Inhalation exposure to metal rich particulate
matter (PM) is known to induce lung
inflammation and compromise host
pulmonary defense mechanisms. While
production of reactive oxygen species
(ROS) leading to intracellular oxidative
stress is a known mechanism of action of
metals, the exact molecular events that
follow metal exposures that trigger the
inflammatory cascade are not fully
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32
understood. In this study, the involvement
of oxidative stress in the release of
chemokines in response to Fe and Se
exposure was evaluated using cultured
human lung alveolar epithelial cells (A549).
We assessed the impact of these elements on
cell viability, ROS generation and IL-8
release over concentration ranges from 0.5
to 10 mM for Fe and 0.005 to 3 µM for Se
for time periods up to 24 hr. Fe was not
cytotoxic over the concentration range
tested, but ROS measured using DCFH-DA
increased over controls 1.25 and 1.5 fold at
0.005 and 0.10 mM Fe, respectively. This
increase in ROS was not associated with an
increased release of IL-8. Se was cytotoxic
to A549 cells over a very narrow
concentration range, dropping from 100%
viability at 1.7 µM to 20% viability at 2.25
µM. Although no measurable change in
ROS production was evident, IL-8
concentrations increased over 10-fold with
increasing exposure from 1.0 to 2.75 µM Se.
Results indicate that release of inflammatory
chemokine by Fe and Se does not appear to
be related to ROS production. Supported by
NIHU56CA96203 and MD DHMH
CH605CRT.
60. BILATERAL SELF-SELECTED
FREQUENCY FINGER TAPPING IN
CHILDREN WITH AND WITHOUT
DEVELOPMENTAL COORDINATION
DISORDER AND ADULTS
Renuka Roche, Anna Maria Wilms-Floet,
Jane E. Clark and Jill Whitall
Afternoon; Poster Presentation; Westminster
Hall
Children with Developmental Coordination
Disorder (DCD) are more variable in timing
their fingers to a concurrent or preceding
external cue, indicating a problem with
auditory-motor coupling. It is not clear
whether this variability is fundamental to the
neuromotor system of those with DCD or a
function of their ability to match their finger
taps to an external cue. In this study, we
investigated the intrinsic coordination
properties of self-selected anti-phase finger
tapping with and without vision and audition
in children with and without DCD and
compared their performance to that of the
adults. Ten children with DCD (Mean age =
7.12 + 0.3 years), ten age- and sex-matched
typically developing (TD) children, and ten
adults participated in this study. Participants
tapped their fingers at a self-selected speed
under four different sensory conditions: 1)
with vision and audition, 2) with vision but
no audition, 3) with audition but no vision,
and 4) without vision and audition. The
variables of interest were frequency of
tapping, variability in frequency of tapping,
mean relative phasing (RP) between the
fingers and the variability in RP. Analyses
showed no significant differences in tapping
performance in the absence of vision and/or
audition, across all groups. Across all
sensory conditions, children with DCD
tapped at a similar mean frequency, but with
greater variability than the other groups. TD
children were more variable than the adults.
Children with DCD also were less
coordinated between their fingers and were
more variable in this coordination than other
groups. Overall, regardless of the sensory
condition and external cues, children with
DCD are more variable in their tapping
frequency and coordination.
61. THE ROLE OF P53 LOSS IN HUMAN
CANCER PROGRESSION AND
THERAPEUTIC RESPONSE
Michele B. Weiss, Michele I. Vitolo, Ben
Ho Park, Kurtis E. Bachman, David J.
Weber
Afternoon; Poster Presentation; Westminster
Hall
The technological advances in high
throughput DNA sequencing has allowed for
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33
the rapid discovery of somatic mutations in
large numbers of primary human cancers.
Understanding the roles such mutations play
in cancer progression is a critical step
towards the development of novel treatment
strategies. Of particular interest is the p53
tumor suppressor gene, the most commonly
mutated gene in human cancer. A nontumorigenic, human cell line model system
to specifically study p53 loss in the absence
of other oncogenic changes has not been
available. Such a model system is key to
investigating the possible direct causal
connection that p53 deficiency may have in
human cancers. To evaluate the biological
and clinical relevance of p53 loss, we have
generated a novel in vitro model systems
using somatic cell knock-out technology.
This knock-out technology has enabled us to
delete p53 in the non-tumorigenic epithelial
cell line, MCF10A. The initial hypothesis to
be tested is that loss of p53, in the absence
of oncogenic mutations, will cause a nontumorigenic cell line to display a more
oncogenic phenotype. Recently, the
homozygous deletion of p53 in four
MCF10A clones was confirmed by PCR
screening and Western Blot analysis. To
date, we have found the MCF10A p53-/clones to have increased migratory potential
as compared to their parental counterparts.
In addition, while MCF10A cells have the
appropriate G1/S and G2/M checkpoint
responses upon DNA damage as assessed by
flow cytometry, the p53-/- clones display a
defective G1/S phase checkpoint response.
Further characterization of each clone is
being performed to assess the utility of p53
loss as a potential biomarker to predict the
therapeutic response of cells treated with
current chemotherapeutic and radiation
regimens.
62. S100A1 Binds The CaM Binding Site
Of RyR1 and Positively Regulates EC
Coupling In Skeletal Muscle
Nathan Wright, Ben Prosser, Martin
Schneider, David Weber
Afternoon; Poster Presentation; Westminster
Hall
S100A1, a small acidic Ca2+ binding
protein, is an enhancer of cardiac
contractility and a potential therapeutic
agent for the treatment of cardiomyopathy.
However the precise molecular mechanism
underlying S100A1 modulation of
sarcoplasmic Ca2+ release in striated muscle
has not been fully elucidated. Here, we show
structural interactions between S100A1 and
RyR that underlie a physiological role of
S100A1 in excitation contraction coupling
in skeletal muscle. Through competition
assays and fluorescence experiments we
identify a novel S100A1 interaction site on
the cytoplasmic face of the intact ryanodine
receptor that is conserved throughout
striated muscle and corresponds to a
previously identified calmodulin binding site
(3610-KKAVWHKLLSKQ). Using a 12mer peptide of this putative binding domain,
we demonstrate low micromolar binding
affinity to S100A1. NMR spectroscopy
reveals this peptide binds within the Ca2+
dependent hydrophobic pocket of S100A1.
We also present the NOE- and RDC-based
solution structure of S100A1 bound to this
peptide, termed RyRP12. Initial analysis
indicates that the structure of S100A1 does
not dramatically differ between the calciumbound and the target-calcium-bound state.
63. MONOAMINE-INDEPENDENT
EFFECTS OF ANTIDEPRESSANTS ON
NEUROLIPID SYNTHESIS IN
CORTICAL AND PC12 CELLS
Marwa Aboukhatwa, Ashiwel Undie
Afternoon; Poster Presentation; Westminster
Hall
Background: The pathophysiology of
depression and its response to various
GRADUATE RESEARCH CONFERENCE
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34
therapies is not fully understood. A well
known mechanism of action of
antidepressant agents is to inhibit synaptic
reuptake of monoamines. Recent studies
showed that antidepressants increase the
levels of CDP-diacylglycerol (CDPDG),
phosphoinositides (PIs) and inositol
phosphate (IP) and that these effects are
critical to the acute behavioral effects of the
drugs. This study aimed to examine the role
of monoamine transmitters in the neurolipid
effects. Methods: The effects of various
concentrations of imipramine (tricyclic),
paroxetine (SSRI) or maprotiline (atypical)
on [3H]cytidine-labeled CDPDG, and
[3H]inositol-labeled PIs were tested in PC12
cells which lack 5HT and NE. Effects of
similar treatments on CDPDG synthase
activity also were measured in brain cortical
slices. Results: Antidepressant treatments
increased the levels of CDPDG and PIs but
not IPs in PC12 cells. Moreover, the drugs
increased CDPDG synthase activity in rat
brain tissues. Conclusions: Antidepressants
increase CDPDG synthesis which then
translates to increased synthesis of PIs.
Activation of CDPDG synthesis may be
independent of monoamines, whereas the
subsequent stimulation of phospholipase C
to convert the PIs into IP second messengers
may depend on monoamine transmitter
activation of PLC-coupled receptors. These
observations strengthen the notion that brain
phospholipid metabolism could be a target
for the therapeutic action of diverse
antidepressants.
64. COMPUTATIONAL MODEL FOR
PREDICTING CHEMICAL
SUBSTITUENT EFFECTS ON PASSIVE
DRUG PERMEABILITY ACROSS
PARALLEL ARTIFICIAL MEMBRANES
Chayan Acharya; Paul R. Seo; James E.
Polli; Alexander D. MacKerell, Jr.
Afternoon; Poster Presentation; Westminster
Hall
Drug permeability is often a limiting step in
drug action, requiring chemical optimization
of drug candidates to improve permeability.
Congeneric series is typically used for such
optimization. In this work the effect of
chemical substituents on passive
permeability across parallel artificial
membranes (PAMPA) was studied for the
congeneric series of benzoic acid, pyridine
and quinoline. Experimental data showed
pyridine and quinoline to have high
permeability and chemical substituents to
typically reduce the permeability. On the
contrary, benzoic acid showed poor
permeability and chemical substituents
typically increased the permeability. To
quantitate these effects models were built to
explain and predict the permeability of these
series based on computed molecular
descriptors. Models for the benzoic acids in
the ionized state indicated the solvent
accessible surface area, cavity dispersion
and the free energy of solvation in hexane
and in water to dominate permeability.
However, when the neutral acid group, the
free energy of solvation in water, the
fraction polar surface area, the polar surface
area and difference in the free energy of
solvation between hexane and water were
important; these terms, among others, were
also important for the pyridines quinolines.
Considering that the permeability of the
benzoic acids is about two orders of
magnitude lower than the pyridines and
quinolines and that the change of pKa by of
the acid group of benzoic acid will make the
neutral species dominant at experimental pH
(6.5) these results suggest that the additional
energy barrier for the permeation of the
benzoic acids is associated with the need to
protonate the acid group, thereby forming
the neutral species which may then cross the
hydrophobic region of the membrane.
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65. SHORT ELECTRONEGATIVE
SEQUENCES MEDIATE BINDING OF
OBSCURIN TO sAnk1
B. Busby, M. A. Borzok, C. D. Willis, A.
Kontrogianni-Konstantopoulos, and R. J.
Bloch
Afternoon; Poster Presentation; Westminster
Hall
Obscurin is a 6,620 amino acid protein that
surrounds the contractile apparatus at Mbands and Z-disks. It has been proposed to
link the contractile apparatus to the network
sarcoplasmic reticulum (nSR) by binding its
C-terminal domain to a small form of
ankyrin (sAnk1), that is an integral protein
of the nSR. Two regions in the C-terminus
have been shown to bind sAnk1, but their
binding characteristics have not been
compared quantitatively. We generated GST
fusion constructs and prepared biotinylated,
synthetic peptides of the 30 residues that
constitute the minimal binding sequences of
each region, and assayed their binding to
sAnk1 fusion constructs by surface plasmon
resonance (SPR) on a Biacore 3000. Histagged sAnk129-155 constructs bound to the
Obsc6316-6345 (NObscK) peptide with 80
nM affinity, whereas they bound to the
Obsc6231-6260 (ObscS) peptide with a
much higher KD (lower affinity). We
obtained similar results with fusion protein
constructs of the obscurin sequences. We
also assayed the ability of the synthetic
peptides in solution to inhibit binding.
Consistent with our direct binding assays,
the NObscK peptide was several-fold more
potent an inhibitor than ObscS in all assays.
Finally, we studied the ability of both
constructs to bind to eight mutants of
sAnk1. We found that mutants of sAnk1
modulated binding of sAnk1 to both
constructs similarly. Our results suggest that
NObscK predominates in binding to sAnk1,
but that the same residues on sAnk1 that
bind to this sequence with high affinity also
mediate binding to ObscS, albeit with lower
affinity. We find it remarkable that a 6620residue protein uses < 30 amino acids to
bind to an integral membrane ligand with
nM affinity.
66. EXPRESSION, REGULATION, AND
INHIBITION OF MATRIPTASE IN
HEMATOLOGICAL NEOPLASM
Feng-Pai Chou, Michael D. Johnson, Ronald
B. Gartenhaus, and Chen-Yong Lin
Afternoon; Poster Presentation; Westminster
Hall
Matriptase, a type II transmembrane serine
protease, possesses potent oncogenic
activity when an imbalance to its cognate
inhibitor, HAI-1, is established in a
transgenic mouse model. The oncogenic
activity of matriptase is in part attributed to
its role in activation of other proteases,
including uPA and MMP3, and
growth/motility factors, including HGF and
its analogue MSP-1. These matriptase
substrates play important roles in
extracellualr matrix-degrading, cellular
motility, cells growth, and angiogenesis. All
of these activities are important for the
development and progression of human
cancers. While most of matriptase studies
have been focused on epithelial and
carcinoma cells in which HAI-1 play a
pivotal role in regulation and inhibition of
matriptase, growing evidence showed that
matriptase may be also important for
hematological neoplasm. Both matriptase
mRNA and protein were detected in primary
effusion lymphoma and indicated it is highly
related with the metastasis of this disease. In
addition, we have examined matriptase
expression in cell lines derived from
Burkett’s lymphomas. The no expression of
HAI-1 and high molecular weight
matriptase-inhibitor complexes in Burkitt's
lymphoma cells has impact to the current
dogma of matriptase-HAI-1 pairing in
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36
epithelial cells. As such, the unopposed
matriptase activity may contribute to some
hematological malignancies.
67. EVALUATING SECOND
GENERATION ERK2 DOCKING
DOMAIN INHIBITORS AS POTENTIAL
ANTICANCER AGENTS
Rahul R. Deshmukh, Alex Mackerell Jr.,
Devapriyakumar Udayakumar, Paul Shapiro
Afternoon; Poster Presentation; Westminster
Hall
The extracellular signal regulated kinase-1
and 2 (ERK-1/2) proteins play an important
role in cancer cell proliferation as well as in
normal cell functions. We have previously
used CADD to identify compounds which
have potential to inhibit specific ERK–
substrate interactions. Based on the
hypothesis that compounds with similar
chemical structure may have similar
physicochemical and biological properties,
we extended these studies further to identify
additional compounds based on their
structural similarity to the active compounds
previously reported. Several new
compounds were tested using binding assays
in which Tryptophan fluorescence
quenching was measured where one
compound has shown 20 fold enhancement
of binding as compared to the parent
compound. Also, the compounds were tested
for the substrate phosphorylation assay and
some compounds have shown to inhibit of
phosphorylation of P90RSK-1 and or Elk-1
and have no effect on P38 MAP Kinase
substrates. In cancer cell lines treated with
different test compounds, the range of IC50
obtained was 10-50 µM in cell proliferation
assays based on colony formation assay and
WST-1 assay. These finding demonstrates
that chemical modification made in silico
using the CADD approach can be used to
identify more potent ERK2 inhibitors based
on structural similarity.
68. STEADY-STATE KINETICS OF
HUMAN THYMINE DNA
GLYCOSYLASE (hTDG) USING A
COUPLED-ENZYME ASSAY:
IMPLICATIONS FOR THE MECHANISM
OF hTDG STIMULATION BY HUMAN
AP ENDONUCLEASE 1.
Megan E. Fitzgerald and Alexander C.
Drohat
Afternoon; Poster Presentation; Westminster
Hall
DNA glycosylases initiate base excision
repair by removing damaged or mismatched
bases, producing an abasic (AP) site in the
DNA. Many glycosylases bind the AP DNA
product tightly, impeding enzymatic
turnover. Human thymine DNA glycosylase
(hTDG), which recognizes G-T mispairs and
other mutagenic lesions, exhibits severe
product inhibition, precluding the use of
steady-state kinetics to study its catalytic
mechanism. To overcome this problem, we
developed a coupled enzyme assay,
monitored by fluorescence, where the
second enzyme, human AP endonuclease
(hAPE1), stimulates the turnover of hTDG.
We determined the steady-state kinetic
parameters for hTDG, and its catalytic core
(hTDG-core, Phe111 to Val308) against a
G-U and G-U5Fsubstrate. These steady-state
kinetic parameters were accurately
determined for the first time, providing
insight into the mechanism of hTDG and the
molecular basis for the stimulation of hTDG
by hAPE1. We find that hAPE1 enhances
the steady state turnover (kcat) of hTDG and
hTDG-core by about 50-fold and 300-fold,
respectively, and that hAPE1 actively
displaces AP DNA from hTDG and hTDGcore. Thus, the 110 N-terminal residues and
102 C-terminal residues of hTDG are not
required for its stimulation by hAPE1.
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69. KINETIC ANALYSIS OF THE
EFFECT OF ALTERING THE CPG SITE
CONTEXT IN HUMAN THYMINE DNA
GLYCOSYLASE
Michael Morgan and Alex Drohat
Afternoon; Poster Presentation; Westminster
Hall
TDG (human thymidine DNA glycosylase)
is an enzyme which functions to remove GT mispairs and other lesions. Previous
studies indicate that hTDG is specific for
lesions paired with G and located at CpG
sites. Such sites are targets for cytosine
methylation, causing T-G mispairs to be
frequent. We have shown that uracil analogs
with varied sizes of substituent at C-5 are
excised much faster than the traditional G-T
substrate on the basis of lessened Nglycosytic bond stability and steric
hindrance (Bennett, M.T., et al JACS 128,
12510-12519). We investigated the
contribution of the 5’-base pair to hTDG
activity using single turnover kinetics with
substrates containing FU, ClU, and BrU
lesions. While overall rates of catalysis
differed with base size as we had previously
observed, altering the identity of the 5’-base
in all cases produced a regular pattern of
efficiency of base excision as follows:
CpG•X>> TpG•X> GpG•X> ApG•X. This
pattern holds for excision of damaged bases
paired with adenine in addition to the
canonical target’s complimentary guanine.
The recent solution of the structure of TDG
bound to duplex DNA suggests two residues
in close proximity and contact to the 5’base, specifically Q278 and K201. Using
site-specific mutagenesis, we propose to
ascertain the roles of these residues in
TDG’s catalytic mechanism using methods
of enzyme kinetics measurement.
70. DUPLIN: A NOVEL A-KINASE
ANCHORING PROTEIN
Maureen O'Donnell, Mary Russell, Meredith
Bond
Afternoon; Poster Presentation; Westminster
Hall
Adaptive changes to scar tissue formation
following myocardial infarction include
hypertrophy, changes in contractility, and
alterations to signaling pathways. This
process of "cardiac remodeling" can
ultimately lead to heart failure (HF), a
condition affecting roughly five million
Americans. Risk of developing HF increases
significantly with age. Changes in gene
expression during remodeling result in an
expression profile similar to the fetal gene
program; therefore understanding the normal
function of these genes may shed light on
their role in pathogenesis and provide clues
to more effective treatment. A-Kinase
Anchoring Proteins (AKAPs) localize
protein kinase A (PKA) within the cell, but
this regulation is altered in HF. The nuclear
protein duplin was recently isolated in phage
display screening of human heart cDNA for
PKA binding proteins. Recent work
demonstrates that this protein binds and
inhibits transcription factors during
development, including signal transducer
and activator of transcription 3 (STAT3).
Altered STAT3 activity is associated with
cardiomyopathy and age-associated HF. To
date, duplin has not been characterized in
the cardiac myocyte. Preliminary
experiments indicate that duplin is expressed
in rat neonatal cardiac myocytes and adult
rat heart. Duplin contains a putative RII
binding site which binds RII in RII overlay
studies. This study will demonstrate that
duplin is a novel nuclear AKAP in the
cardiac myocyte. In addition, mutagenesis
and reporter assays will be utilized to
characterize the role of duplin-anchored
PKA on STAT3 activity. Characterizing a
novel nuclear AKAP will further elucidate
the function of this unique class of nuclear
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38
A-kinase anchoring proteins and will
document a novel function for this important
developmental protein.
71. MATRIPTASE COMPLEXES WITH
SECRETED SERPINS: A NOVEL
MECHANISM FOR MATRIPTASE
INHIBITION IN THE EXTRACELLULAR
MILIEU
I-Chu Tseng, Feng-Pai Chou, Sheng-Feng
Su, Michael Oberst,
NandakumarMadayiputhiya, Chen-Yong
Lin
Afternoon; Poster Presentation; Westminster
Hall
In epithelial cells, matriptase is tightly
regulated by hepatocyte growth factor
activator inhibitor 1 (HAI-1) which serves
as an inhibitor and a factor required for
activation of matriptase. As a consequence,
matriptase activation is immediately
followed by HAI-1-mediated inhibition,
probably before active matriptase arrives at
the extracellular milieu. In contrast,
leukocytes express matriptase but no HAI-1,
suggesting alternate, HAI-1 independent
mechanisms for activation and inhibition of
matriptase in leukocytes. In the current
study, novel matriptase complexes,
containing no HAI-1, was purified from
human milk and dissociated into 80-kDa and
45-kDa fragments by dithiothreitol.
Proteomic and immunological methods
identified the 45-kDa fragment as the noncatalytic domains of matriptase and the 80kDa fragment as the matriptase serine
protease domain covalently linked to one of
three different secreted serpin inhibitors:
antithrombin III, alpha 1 antitryspin, and
alpha 2 antiplasmin. These results suggest
that free, active matriptase, possible from
migrating leukocytes, can reach the
extracellular environment where it can
activate its substrates at the plasma
membrane or in the extracellular milieu
where it is inhibited by secreted serpins.
72. PATHWAYS INTO SOCIAL WORK
FOR LATIN AMERICANS WITH MSWS:
A PRELIMINARY QUALITATIVE
STUDY
Karen Castellanos-Brown
Morning; Oral Presentation; SSW/Law
Building 519
This presentation reports on a preliminary
qualitative study exploring Latin American
social workers’ pathways into social work. It
also focuses on exploring the role Latin
American organizations play in students’
lives. While literature on factors
contributing to educational achievement
among Latin Americans exists, literature on
the pathways to succeeding in social work
programs and on the role that Latin
American organizations play in students’
lives is lacking. Utilizing a grounded theory
model, this study collects data from multiple
sources: interviews and observations. Two
Masters level Latin American social workers
were interviewed for this study and various
observations were made as part of this study.
Findings from this study suggest that for
Latin Americans with risk factors, the
presence of protective factors is necessary
for the pursuit of educational advancement.
Findings also suggest that participation in a
Latin American organization can be an
important protective factor for Latin
American students when schools of social
work lack role models and mentors for Latin
American students.
73. EXPLORING CPS PRACTITIONERS’
COGNITIVE AND EMOTIONAL
APPRAISALS OF THEIR DECISIONS
Sunday Fakunmoju
Morning; Oral Presentation; SSW/Law
Building 519
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39
Child protective services (CPS) practitioners
who investigate allegations of maltreatment
make decisions in their professional
practice. They assess safety and risk factors
related to children and families, remove
children from unsafe environments, and
make depositions about maltreatment
allegations. Although the results of existing
empirical studies suggest case and personal
factors influence decisions these
practitioners make, there is little known
about what they think and how they feel
about their decisions. Yet, despite successful
CPS interventions, there are consequences
of poor decision making and clinical
judgment. There also is evidence of public
scrutiny and negative public perceptions of
CPS decisions. Because CPS practitioners
may have concerns about the outcomes of
their decisions, exploring their self
appraisals (i.e., cognitive and emotional) of
their decisions and the impacts of such
appraisals on case outcomes may deepen our
understanding of CPS decision making
beyond the current knowledge base.
Similarly, because CPS practitioners’
decisions have significant impacts on the
lives of children and families, knowing the
cognitive and emotional dimensions of their
decision making process may provide useful
information for developing interventions
that may improve their decision making
skills and enhance better outcomes for
children and families. Therefore, this
presentation examines the current
knowledge base of factors influencing
decision making and case outcomes in CPS,
reports the practitioners’ cognitive and
emotional appraisals of their decision
makings, and discusses the need to explore
cognitive and emotional aspects of
practitioners’ decision making in CPS.
74. UNDERSTANDING AND
ADDRESSING THE NEEDS OF FOSTER
CHILDREN WITH INCARCERATED
PARENTS
Anna Hayward
Morning; Oral Presentation; SSW/Law
Building 519
As the nation’s prison population grows,
children and families are increasingly
affected. The growing number of
incarcerated women is of particular concern
as research suggests that the majority of
these women are parents. Children with an
incarcerated parent make up a small but
growing percentage of the foster care
population and may have needs not readily
met by standard child welfare services.
Using data from the Adoption and Foster
Care Reporting System (AFCARS) this
presentation will explore characteristics of
children in out-of-home care with identified
parental incarceration (n=45,284). In
addition, current research, best practices,
and available services will be discussed as
well as future directions in research and
practice to better serve this vulnerable
population
75. Genome-wide Linkage and Association
Analyses to Identify Genes Influencing
Adiponectin Levels: the GEMS Study
Hua Ling, Dawn M. Waterworth, Heide
Stirnadel, Toni I. Pollin, Vincent E. Mooser,
Braxton D. Mitchell
Morning; Oral Presentation; SSW/Law
Building 519
Adiponectin has a variety of metabolic
effects on obesity, insulin sensitivity and
atherosclerosis. To identify genes
influencing variation in plasma adiponectin
levels, we performed genome-wide linkage
and association scans of adiponectin in two
cohorts of subjects recruited in the GEMS
study. The genome-wide linkage scan was
conducted in Mediterranean (Med, n = 789)
and non-Mediterranean (non-Med, n =
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40
2,280) origin families. A whole genome
association (WGA) analysis (500K
Affymetrix platform) was carried out in a set
of unrelated non-Med subjects consisting of
approximately 1000 subjects with
dyslipidemia and 1000 overweight subjects
with normal lipids. Peak evidence for
linkage occurred at chromosome 8p23 in
non-Med subjects (LOD = 3.10) and at
chromosome 3q28 near ADIPOQ, the
adiponectin structural gene, in Med subjects
(LOD = 1.70). In the WGA analysis, the
SNPs most strongly associated with
adiponectin were rs3774261 and rs6773957
(p≤10-7). These two SNPs were in high LD
(r2 = 0.98) and located within ADIPOQ.
Interestingly, our fourth strongest region of
association (p ≤ 2*10-5) was to a SNP
within CDH13, whose protein product is a
newly identified receptor for highmolecular-weight species of adiponectin.
Through WGA analysis, we confirmed
previous studies showing SNPs within
ADIPOQ to be strongly associated with
variation in adiponectin levels and further
observed these to have the strongest effects
on adiponectin levels throughout the
genome. We additionally identified a second
gene (CDH13) possibly influencing
variation in adiponectin levels. The impact
of these SNPs on health and disease has yet
to be determined.
76. DEPLOYMENT RISK AND
RESILIENCE: A CONCEPTUAL MODEL
Nikki R. Wooten, MSW, LCSW-C
Morning; Oral Presentation; SSW/Law
Building 519
Field not available upon submission
77. CHANGES IN CARDIOVASCULAR
RISK OVER TIME: A COMPARISON OF
FRAMINGHAM RISK SCORES, 19881994 TO 1999-2004
Katrina Rhodes, M.D., Lisa D. Gardner,
John D. Sorkin, M.D., Ph.D.
Morning; Poster Presentation; Westminster
Hall
Background: Obesity increases the risk for
coronary heart disease (CHD), the number
one cause of mortality in U.S. adults. As the
prevalence of obesity has increased in recent
years, the medical management of obesityrelated conditions has improved, which may
counteract the expected obesity-related
increase in CHD risk. Methods:
Framingham risk scores (FRS), a measure of
10-year CHD risk, were compared between
the current U.S. population and the
population in 1988-1994, using data from
the National Health and Nutrition
Examination Survey (NHANES) 1999-2004
and NHANES III (1988-1994). All
comparisons were stratified by age (30-34,
35-44, 45-54, 55-64, and 65-74 years), sex,
and race (non-Hispanic white, non-Hispanic
black, and Mexican American). Results:
From NHANES III to NHANES 1999-2004,
FRS decreased in older non-Hispanic white
men (< 35 years; p ≤; 0.037) and women (>
55 years; p ≤ 0.001), and in older Mexican
American men (> 65 years; p = 0.005) and
women (35-44 and 65-74 years; p ≤ 0.022).
Non-Hispanic black men (30-34 and 65-74
years; p ≤ 0.050), but not women, showed
significant decreases in FRS. Decreases in
CHD risk were explained by reductions in
total cholesterol and blood pressure with
age. After adjusting for age, sex, and race,
the current U.S. population (NHANES
1999-2004) has a lower 10-year CHD risk
than the U.S. population in 1988-1994
(NHANES III). Stratification by age, sex,
and race revealed racial differences in 10year CHD risk and risk factors over time.
Conclusion: Despite the increasing
prevalence of obesity in the U.S. population,
CHD risk has declined. The benefits appear
to be greater in non-Hispanic white men and
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41
women. While decreases in FRS and 10year CHD risk were seen, follow-up will be
needed to see if risk decreases as predicted.
78. ROLE OF CEREBROVASCULAR
DISEASE &amp; THE ASSOCIATION
BETWEEN DIABETES MELLITUS AND
DEMENTIA AMONG AGED MEDICARE
BENEFICIARIES
Zhiqiang Lu, Bruce Stuart, Ilene Zuckerman
Morning; Poster Presentation; Westminster
Hall
OBJECTIVES: To assess whether diabetes
mellitus is associated with overall dementia
and its subtypes among the elderly; to
identify the role of cerebrovascular disease
in the association. DESIGN: Retrospective
cross-sectional study. SETTING: Medicare
Beneficiaries in 2002. PARTICIPANTS:
8,132 community-dwelling and
institutionalized Medicare beneficiaries aged
65 or over without HMO enrollment from
the Medicare Current Beneficiary Survey.
MEASUREMENTS: The key predictor was
diabetes mellitus and the outcome was
overall dementia and its subtypes. Potential
confounders considered were gender,
education, income, smoking status and
cerebrovascuar disease. The International
Classification of Diseases, Clinical
Modification (ICD-9-CM) codes were used
to identify the outcome and independent
variables from the Medicare claims files for
each respondent in 2002. RESULTS: After
adjusting for potential confounders, diabetes
mellitus was significantly associated with
overall dementia (OR=1.63; 95% CI, 1.351.97), vascular dementia (OR=1.56; 95%
CI, 1.27–1.92), and Alzheimer’s disease
(OR=1.36, 95% CI, 1.03-1.78). The ORs
decreased to 1.39 (95%CI, 1.14-1.69) and
1.30 (95%CI, 1.05-1.61) for overall
dementia and vascular dementia,
respectively, controlling for cerebrovascular
disease. The association between diabetes
mellitus and Alzheimer’s disease was no
longer statistically significant once
cerebrovascular disease was controlled
(OR=1.16, 95%CI, 0.87-1.55).
CONCLUSIONS: The association between
diabetes mellitus and dementia is only
partially mediated through cerebrovascular
disease, suggesting that diabetes mellitus is
associated independently with overall
dementia and vascular dementia among the
elderly, but not with Alzheimer’s disease.
79. ACCULTURATION &amp;
DIABETIC IMMIGRANT ELDERS IN
THE US: IMPLICATIONS FOR AN
OVERLOOKED &amp; BURGEONING
POPULATION
Maria C. Okafor
Morning; Poster Presentation; Westminster
Hall
Diabetes is an epidemic of global
proportions affecting individuals of all ages,
races and ethnicities. In recent times, as the
influx of immigrants to the United States has
increased, studies examining the impact of
acculturation on the health of immigrant
populations have also increased. However,
little is known about the impact of
acculturation on diabetes among older adult
immigrants. A critical review of the
literature was conducted to: 1) provide a
description of current research on diabetes
and acculturation as it pertains to older
immigrants residing within the United States
2) determine the strengths and weaknesses
of current research and 3) identify goals for
future research. A search of 1145 abstracts
was conducted using earliest available
records through 3/1/2007 on Medline
(n=1013) and PubMed (n=132). From these
abstracts, 70 articles were identified and a
total of 13 articles were reviewed. Findings
from this review indicate that studies of
African, African-Caribbean and Hispanic
immigrant populations are lacking, while
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those of Arab and Asian immigrants are
more abundant. Across all immigrant
groups, the elderly remain a small
proportion of sampled subjects (mean age of
subjects across all studies = 44.26). Studies
reviewed were limited by 1) small sample
sizes 2) definition/operationalization of
acculturation 3) lack of generalizability in
acculturation measures 4) minimal account
of effect modifiers and/or confounders 5)
insufficient demographic profile of subjects
and 6) reliance on self report data. Future
research should include the older immigrant
adult. Ethnically diverse cross sections of
older immigrants and culturally sensitive
screening tools and measures are needed to
adequately explore health outcomes in this
population.
80. Generational Differences in the
Relationship Between Sense of Community
and Social Capital
Kathleen H. Powell
Morning; Poster Presentation; Westminster
Hall
There is increasing recognition in interdisciplinary professional circles of the
importance of social networks in individual
and collective health and well-being. Using
secondary data from the Social Capital
Benchmark Survey (Putnam, 2000), this
study sought to explore the relationship
between individuals' sense of community
and their level of civic engagement or social
capital and the degree to which these
variables were influenced by age and
employment status. The data were analyzed
using a multiple regression model and
findings discussed in light of their
implications for social work practice.
81. ABSENCE OF RELATION OF
DEPRESSIVE SYMPTOMS TO
DIABETES DIAGNOSIS, AND
GLYCATED HEMOGLOBIN IN THE
HANDLS STUDY
Melissa C. Rice, Gerontology, UMB,
Baltimore, MD, S. Carrington Rice,
Psychology, UMBC, Baltimore, MD,
Michele K. Evans, Alan B. Zonderman,
Intramural Research Program, NIA,
Baltimore, MD, Shari R. Waldstein,
Psychology, UMBC, Baltimore, MD
Morning; Poster Presentation; Westminster
Hall
Depressive symptoms have been shown to
precede the development of diabetes.
However, little is known about the
association between depressive symptoms
and glycated hemoglobin (HbA1c) in
persons with and without diabetes. Here we
examined the relations of depressive
symptoms to (1) diabetes diagnosis; (2)
HbA1c in self-reported diabetics; and (3)
HbA1c among those without a diagnosis of
diabetes. Participants derived from the
baseline assessment visit of The Healthy
Aging in Neighborhoods of Diversity across
the Life Span (HANDLS) study - a new 20year longitudinal investigation of
community-dwelling Black and white adults
ages 30-64. After exclusion for HIV/AIDS,
neurological disease, schizophrenia, and
bipolar disorder, 198 participants with selfreported diabetes and 953 participants
without self-reported diabetes were available
for data analysis. Participants completed the
Center for Epidemiologic StudiesDepression Scale (CES-D), and provided a
blood sample for determination of HbA1c.
All analyses were adjusted for
sociodemographic factors, cigarette use,
waist circumference, cardiovascular disease,
and hypertension and all possible two and
three way interactions were examined.
Results of logistic regression revealed no
significant association of depressive
symptoms to diabetes diagnosis. Among
those with diagnosed diabetes and those
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43
without diagnosed diabetes, multiple
regression analysis indicated no significant
relation of depressive symptoms to HbA1c.
Thus, in this community-dwelling sample,
depressive symptoms were not associated
with diagnosis of diabetes or glycemic
control.
82. RACE AND HEALTH CARE
PROFESSIONAL RECOMMENDATIONS
FOR COLORECTAL CANCER
SCREENING
Shayna E. Rich; Fatmatta M. Kuyateh; Min
Zhan; Mary-Claire Roghmann; Diane
Dwyer; Carmela Groves; Eileen Steinberger
Morning; Poster Presentation; Westminster
Hall
Background: Colorectal cancer (CRC)
screening rates are lower for Blacks than
Whites. It is not clear whether this
difference is due to a disparity in patienthealth care professional (HCP) interactions.
This study examined whether race is
associated with reporting HCP
recommendations for CRC screening.
Methods: A cross-sectional study was
performed among 2,723 White and 657
Black Maryland residents aged 50 years or
older in the 2004 Maryland Cancer Survey.
Respondents were asked whether they had
ever received an HCP recommendation for a
sigmoidoscopy/colonoscopy, whether they
had received a recommendation for a fecal
occult blood test (FOBT) in the past year,
and about their CRC screening history.
Results: 70% reported a recommendation
for sigmoidoscopy/colonoscopy (72% of
Whites vs. 62% of Blacks, p&lt;0.001).
Among respondents who did not report an
up-to-date colonoscopy, 34% reported a
recommendation in the past year for an
FOBT. In multivariable analyses, the
association between respondent race and
recommendation for
sigmoidoscopy/colonoscopy varied by
employment. The odds of reporting a
recommendation for
sigmoidoscopy/colonoscopy among retired
Whites were 1.21 times those of retired
Blacks (95% CI 0.89-1.64), while the odds
among non-retired Whites were 1.56 times
those of non-retired Blacks (95% CI 1.202.03). The odds of reporting a
recommendation for FOBT did not differ
significantly between Whites and Blacks
among respondents who did not have an upto-date colonoscopy (OR 0.96, 95% CI 0.741.25). Conclusions: White respondents
were more likely than Blacks to report a
HCP recommendation for
sigmoidoscopy/colonoscopy. No such
difference existed for recommendation for
FOBT in the past year.
83. JOB SATISFACTION AMONG CASE
MANAGERS FOR COMMUNITYDWELLING OLDER ADULTS
Ying Tang
Morning; Poster Presentation; Westminster
Hall
Background: Job satisfaction of case
manager can enhance job performance and
improve its social outcome. Yet, little is
known about job satisfaction among the
emerging group of case managers who work
exclusively with community-dwelling older
adults. Objective: To determine the level of
overall job satisfaction and some of its
determinants among case managers of the
Visiting Nurse Health System, Atlanta,
Georgia and to explore how they perceive
their role and the factors facilitating or
impeding case management. Methods:
Forty-one of the 61 case managers (nurses
and social workers) completed the Job
Satisfaction Survey and a demographic
survey. Nine out of eleven randomly
selected case managers participated in the
follow-up in-person interview. Results: The
overall job satisfaction scores of ranged
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44
from 109 to 198, with a mean of 158.2 (out
of a maximum score of 216), slightly higher
than that of case managers in mental health
services. Interview results revealed that case
managers tended to describe their role in
terms that were either related to program
objectives or activities, and more as
providing or ensuring services to their
clients than as cost-containment. Nature of
the work, management, and coworkers were
the major facilitating factors, and the
majority of deterring factors fell in the
category of organizational factors, such as
operating procedures, pay, promotion and
supervision. Conclusion: Autonomy and
positive coworker relationship are factors
highly beneficial to job satisfaction for case
managers. Policy changes might be needed
at the organizational level to enhance job
satisfaction among case managers.
84. ANTIDEPRESSANT TREATMENT
OF MEDICAID-INSURED YOUTH WITH
CANCER
Satish Valluri, M.S., M.P.H., University of
Maryland 220 Arch Street, Baltimore,
Maryland 21201; J. M. Zito, Ph.D; E.
Ballard, B.A.; D. Safer, M.D.; J. Korelitz,
Ph.D.; L. Magder, Ph.D.; L. Horowitz,
Ph.D, M.P.H.; A. Wayne, M.D.; D.
Mattison, M.D.; M. Pao
Morning; Poster Presentation; Westminster
Hall
The primary objective of this study is to
determine whether there is an association
between a clinical diagnosis of cancer and
antidepressant use in youth. Data were
extracted from the administrative claims
files of 7 state Medicaid programs. Youth,
ages 2 through 17 years, who were
continuously enrolled in Medicaid for 3 or
more months during 2000-2001 were
included. A cancer case (n = 1,040) was
designated if at least two ICD-9-CM cancer
codes were present in the outpatient
physician visit claims data and the youth
was enrolled for at least 3 months following
the first of these cancer diagnoses (index
date). The comparison group (n = 10,400)
was formed by randomly selecting for each
case 10 gender, age, and race matched
individuals who did not receive a cancer
diagnosis or a chemotherapeutic drug.
Antidepressant use was defined as having
one or more antidepressant prescriptions
dispensed after the index date.
Antidepressant use was compared in the two
groups using a hazards ratio. After
controlling for gender, age, race and
psychiatric co-morbidities, the likelihood of
antidepressant use in cancer cases relative to
the comparison youth was 1.87 (95% CI
1.43-2.44). Black and Hispanic youth had
lower rates of antidepressant use (0.39, 95%
CI 0.28-0.55 and 0.40, 95% CI 0.26-0.61
respectively) compared to white youth. The
presence of ADHD or another psychiatric
diagnosis excluding anxiety and depression
increased the likelihood of antidepressant
use (5.41, 95% CI 4.31-6.79 and 3.94, 95%
CI 3.14-4.93 respectively). Data from
outpatient visits of Medicaid-insured youth
in 7 states suggest that antidepressant use is
approximately twice as likely in cancerdiagnosed youth relative to a gender, age,
and race matched non-cancer group, after
adjusting for psychiatric diagnoses.
85. ASSESSING THE ROLE OF
PARENTAL BEHAVIOR IN THE
FORMATION OF ATTITUDES
TOWARDS DEVIANCE AMONG
AFRICAN AMERICAN ADOLESCENTS
Saltanat Dushalieva, MSW, Von Nebbitt,
PhD
Afternoon; Poster Presentation; Westminster
Hall
Research on adolescent development has
identified numerous factors that affect
adolescent’s attitudes towards delinquent
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45
behavior. Parental supervision and
encouragement have been indicated as a
major predictor of adolescent’s academic
performance, decision making, and selfesteem. Conversely, a lack of parental
support and monitoring is cited as a
correlate of adolescent substance abuse and
delinquent behavior. Using the sample of
401 African American adolescents who
participated in the study Context Maters:
Violence Exposure and Adolescents’ Health,
this paper assesses the role of maternal and
paternal supervision and encouragement on
shaping the attitudes towards deviance
among African American youth living in
urban public housing communities. Results
from the multiple regression analysis will
examine the moderating effect of family
violence on the relationship between
parental behavior and attitudes towards
deviance. Implications for social work
practice and research will be discussed.
86. A measurement model of the selfevaluated core competencies among
Taiwanese nursing students
SUH-ING HSIEH and LI-LING HSU
Afternoon; Poster Presentation; Westminster
Hall
Background: The focus on developing and
assessing competency is a crucial issue in
providing safe and efficient patient care
(Freiburger, 2003). Yet, current assessments
are often self-ratings with limited attention
to psychometric principles. The Taiwan
Nursing Accreditation Council idefined
eight core competencies for the BSN
(Chung &amp; Hsu, 2007). Based on these 8
competencies, Hsu developed an 8-item
Self-Evaluated Core Competencies scale
(SECC). Yet, the scale is in early
development and has undergone limited
psychometric testing. Objective: To explore
the underlying factor structure of this scale
to provide preliminary psychometric support
for the scale and test validity. Methods: Data
from the study of the Transferable Skills of
Nursing Students on Job Market
Performance in Taiwan included the SECC.
The convenience sample includes of 802
female BSNs. An exploratory factor
analyses was conducted using LISREL 8.8
and diagonally weighted least squares were
used. Results: The age of BSNs range from
21 to 56 years (25.82±5.53) and nursing
experience ranges from 0 to 30 years
(2.12±4.92). The Cronbach’s ? was 0.80.
Two latent variables were labeled as:
Humanity/ responsibility and cognitive/
performance, each with four indicators.
Therefore, the final measurement model of
the SECC was converged to an admissible
solution in 15 iterations. All parameters are
significant and goodness of fit indices
demonstrate acceptable fit: ?2 = 37.73
(p=0.001). Conclusion: The initial model of
SECC was a poor fit necessitating
respecification. The final model measured
the constructs of humanity/responsibility
and cognitive/performance for core
competencies with a correlation coefficient
.80 (convergent validity). These five
indicators had correlated measurement
errors.
87. Transformational Leadership and
Follower Performance in human service
organization.
Jeongha Hwang
Afternoon; Poster Presentation; Westminster
Hall
The pace of change confronting
organizations today has resulted in calls for
more adaptive, flexible leadership. In line
with this, transformational leaders enable
followers to generate creative solutions to
complex problems, while also developing
responsibilities. However, there has been
little empirical attention to the concepts of
transformational leadership and performance
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in human services. The purpose of this
research is threefold. First, it examines the
effectiveness of transformational leadership
style in human service organization.
Secondly, it provides us with clues on how
to make the operation of human service
organizations more systematic or scientific.
Finally, it provides some implications for
social work. In total, 230 questionnaires
were delivered to 33 human service
organizations in Seoul, Korea by mail. The
142 completed questionnaires were returned
and finally used for analysis (61.7 percent
response rate). The independent variable is
the transformational leadership style. This is
measured based on the Multi-factor
leadership questionnaire (MLQ) developed
by Bass (1985). Transformational leadership
was measured through the sub-dimensions
of charisma, intellectual stimulation, and
individualized attention (? =. 95). The
dependent variable is the perception of job
performance of social workers working in
human service organizations. The study uses
performance measurement devised by
Kadushin (1992) to measure the job
performance of social workers (? = . 85). A
cross-sectional design is used. Mean and
standard deviations of all variables are
calculated. Multiple regressions are
conducted to examine the effects of
predictors on the outcome variables.
88. EFFECTS OF PERSONORGANIZATIONAL VALUE FIT ON
SOCIAL WORKERS' INTENTION TO
LEAVE
HaeJung Kim
Afternoon; Poster Presentation; Westminster
Hall
Recently, there has been an increasing
concern with person-organizational value fit
as a predictor of organizational performance
in for profit organizations. Values can be
more important to both human service
workers and human service organizations
than for-profit-organizations. At the
individual level, social workers are required
to respect professional ethics in practice,
preserve cultural values, and maintain their
unique social and moral identity. At the
organizational level, social work
organizations are constrained by socially
dominant values, and their organizational
values are the most important element of
their culture. This study examined the
relationship between person-organizational
value fit and social workers’ intention to
leave. A self-administered survey was
mailed to a sample of 366 social workers in
Seoul, Korea, 2002 and 204 surveys were
returned (56 %). To assess workers’
individual and organizational value fit,
social workers who have worked less a year
in the organizations excluded from the final
data analysis; one hundred and seventy five
surveys were used in final data analysis.
Hierarchical multiple regression analysis
was conducted. The final model was
significant (F= 8.244, p&lt;.001) and
accounted for 28.4% of the variance
(Adjusted R square change = .250). The
results suggested that person-organizational
value fit predicted social workers’ intention
to leave. When demographic factors and role
factors were controlled, value fit accounted
for additional 6.3% of variance in intention
to leave and value fit had the strongest
impact on social workers’ intention to leave
in the organization.
89. CRITICAL CARE PERFORMANCE
IN A SIMULATED MILITARY
AIRCRAFT CABIN ENVIRONMENT
McNeill, Margaret M
Afternoon; Poster Presentation; Westminster
Hall
Critical Care Air Transport Teams
(CCATTs) care for 5-10% of injured/ill
warriors transported on military aircraft for
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definitive treatment. Purposes of this study
were to determine effects of altitude-induced
hypoxia and aircraft cabin noise, and to
examine contributions of fatigue and clinical
experience, on cognitive/physiological
performance of CCATT providers. This
repeated measures 2x2x4 factorial study had
a sample of 60 military nurses. Participants
completed a simulated patient scenario
under aircraft noise/altitude conditions.
Cognitive performance was measured with
Critical Care (CC) Scores, CC
Errors/Omissions, and CC Reaction Times
during the scenario. Physiological
performance was measured via vital signs
and oxygen saturation. Differences in
performance were analyzed using RM
ANOVA. A multiple regression model was
developed to determine the independent
contribution of fatigue and clinical
experience to performance as a function of
altitude and noise. CC Scores (p = .020) and
Errors/Omissions (p = .047) were negatively
impacted by noise. Noise resulted in an
increase in respiratory rate (p = .019). CC
Scores (p≤ .001) and Errors/Omissions (p =
.002) worsened with altitude. Heart rate (p
≤.001) and respiratory rate (p ≤ .001)
increased with altitude, and oxygen
saturation (p≤ .001) decreased. A regression
analysis of CC Reaction Time to First
Defibrillation with altitude, noise, fatigue,
current critical care experience, and
experience accounted for 20% of the
variance in reaction time (p = .028). Care of
critically ill patients is significantly affected
by noise/altitude. Noise and altitude act
independently. Safety and quality of care
may be positively impacted with training
and equipment better designed for
monitoring/assessment during air transport.
90. MAKING DISTANCE EDUCATION
WORK FOR SOCIAL WORK COURSES:
A REVIEW OF THE LITERATURE
Karen Rice, MSW, LSW, ACSW
Afternoon; Poster Presentation; Westminster
Hall
Distance education has been utilized in
higher education for more than one hundred
years. It is a means to offer an education to
those, due to their location would otherwise
not be able to obtain. Further, distance
education, as opposed to traditional
classroom education, tends to better fit the
needs of older adults whose busy lifestyle
may prevent them from attending classes at
a specified time. Regardless of the reason
distance education is offered, the quality of
the course should not be compromised. In
social work, a field grounded in face-to-face
interaction, the ability to ensure a quality
education may be more challenging.
However, when considering distance
education for a social work course, the focus
needs to be on which medium will best
accomplish the goals of that particular
course and how best to design the course so
as not to jeopardize students’ satisfaction
and performance. This paper will review the
literature on research completed regarding
the satisfaction and performance outcomes
of students enrolled in various social work
distance education courses offered through
interactive TV and the internet. Based on
this literature, suggestions will be made on
how to craft a social work distance
education course depending upon the course
type (knowledge or skills based) and
medium utilized.
91. HAART PRESCRIBING IS
SIGNIFICANTLY ASSOCIATED WITH
HOUSING STATUS
Anthony Tommasello, Vickie Dailey, YuJung Wei, Van Doren Hsu, Louise Treherne
Afternoon; Poster Presentation; Westminster
Hall
Background: Homelessness is a barrier to
healthcare. Housing stability is positively
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associated with good health outcomes for
HIV people. Homeless people with
HIV/AIDS may not receive Highly Active
Antiretroviral Therapy (HAART) because
physicians presume they are unlikely to
adhere to the regimen, which can lead to
drug resistant and HIV may spread into the
community. Health Care for the Homeless
(HCH) in Baltimore, MD provides joint
services of housing and comprehensive
services to HIV infected homeless with
concurrent substance abuse and/or mental
illness through the CONNECT project. We
report here analyses of the relationships
between 1) housing stability and the
initiation of HAART and 2) service delivery
and housing stability. Methods: Participants
(n = 98) were recruited from HIV clinics
through the CONNECT Project from
September, 2002 to September, 2005. A
routine encounter record was created at each
visit of HCH services. These records
constituted the demographic characteristics,
housing status, and service delivery
information including HAART prescribing.
Chi-Square and t-test were used to examine
the relationships between age, race, gender,
service delivery and housing stability and
being on HAART. Results: There were
68.1% of participants housed and 50.5% on
HAART. Age, race and gender were not
related to being either housed or on
HAART. However, being housed was
strongly associated with being on HAART
(odds ratio=4.8, X2=11.5, p&lt;0.001).
Numbers of encounters and services, weekly
encounters, and service intensity did not
differ significantly between those on
HAART and those not on HAART and
between those housed and not housed.
Conclusions: Those housed are significantly
more likely to receive HAART than those
not housed
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PRESENTER INDEX
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50
Aboukhatwa, Marwa; Poster, Afternoon, Westminster Hall: 63
Acharya, Chayan; Poster, Afternoon, Westminster Hall: 64
Baker, Kelly; Oral, Morning, BRB 1-008: 7
Baksh, Charlene; Poster, Afternoon, Westminster Hall: 54
Balzer, Eric; Poster, Morning, Westminster Hall: 23
Bernstein, Jade; Oral, Morning, BRB 1-008: 8
Bissonette, Greg; Poster, Morning, Westminster Hall: 24
Brennan, Sarah; Oral, Morning, SSW/Law Building 302: 38
Bruno, Robert; Oral, Morning, BRB 1-008: 9
Busby, Ben; Poster, Afternoon, Westminster Hall: 65
Bushar, Nicholas; Oral, Morning, BRB 1-008: 10
Castellanos-Brown, Karen; Oral, Morning, SSW/Law Building 519: 72
Chalmers, Natalia; Poster, Morning, Westminster Hall: 14
Chandran, Smita; Oral, Afternoon, SSW/Law Building 302: 39
Charpentier, Thomas; Poster, Morning, Westminster Hall: 25
Chen, Fengming; Poster, Afternoon, Westminster Hall: 55
Cho, Edward; Poster, Morning, Westminster Hall: 26
Chou, Feng-Pai; Poster, Afternoon, Westminster Hall: 66
Dave, Vivek; Poster, Afternoon, Westminster Hall: 56
Dean, Shannon; Oral, Afternoon, SSW/Law Building 302: 40
Deshmukh, Rahul; Poster, Afternoon, Westminster Hall: 67
Dorff, Sarah; Oral, Morning, SSW/Law Building C-001: 1
Dosanjh, Laura; Poster, Morning, Westminster Hall: 15
Dushalieva, Saltanat; Poster, Afternoon, Westminster Hall: 85
Evans, LaShauna; Poster, Morning, Westminster Hall: 31
Fakunmoju, Sunday; Oral, Morning, SSW/Law Building 519: 73
Fang, Liang; Poster, Morning, Westminster Hall: 16
Fitzgerald, Megan; Poster, Afternoon, Westminster Hall: 68
Gardner, Lisa; Poster, Morning, Westminster Hall: 77
Gianulis, Elena; Poster, Morning, Westminster Hall: 17
Gustina, Ahleah; Poster, Afternoon, Westminster Hall: 46
Harris, Kristina; Poster, Morning, Westminster Hall: 27
Hayward, Anna; Oral, Morning, SSW/Law Building 519: 74
Holder, Mary; Oral, Afternoon, SSW/Law Building 302: 41
Holt, Dawn; Poster, Morning, Westminster Hall: 28
Hsieh, Suh-Ing; Poster, Afternoon, Westminster Hall: 86
Hsu, Wenchi; Poster, Morning, Westminster Hall: 32
Hwang, Jeongha; Poster, Afternoon, Westminster Hall: 87
Jin, Feiyan; Poster, Afternoon, Westminster Hall: 57
Jones-Lush, Lauren; Poster, Morning, Westminster Hall: 18
Khandelwa, Aakanksha; Oral, Afternoon, SSW/Law Building 302: 42
Khanna, Ira; Poster, Afternoon, Westminster Hall: 47
Khantwal, Chandra; Oral, Afternoon, SSW/Law Building 302: 43
Kim, Hae Jung; Poster, Afternoon, Westminster Hall: 88
Kundoor, Vipra; Poster, Afternoon, Westminster Hall: 48
Levine, Jonathan; Oral, Morning, SSW/Law Building C-001: 2
GRADUATE RESEARCH CONFERENCE
THURSDAY, APRIL 3, 2008
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Li, Yanchun; Oral, Morning, SSW/Law Building C-001: 3
Lim, Han; Poster, Afternoon, Westminster Hall: 49
Ling, Hua; Oral, Morning, SSW/Law Building 519: 75
Liriano, Melissa; Oral, Morning, SSW/Law Building C-002: 4
Lu, Zhiqiang; Poster, Morning, Westminster Hall: 78
Manvilla, Brittney; Poster, Morning, Westminster Hall: 33
Martins, Gabriela; Poster, Afternoon, Westminster Hall: 58
Matrone, Michael; Poster, Morning, Westminster Hall: 29
McDowell, Kimberly; Oral, Morning, SSW/Law Building C-001: 5
McNeill, Margaret; Poster, Afternoon, Westminster Hall: 89
Michaelson, Luke; Poster, Afternoon, Westminster Hall: 50
Molitoris, Kristin; Poster, Morning, Westminster Hall: 19
Morgan, Michael; Poster, Afternoon, Westminster Hall: 69
O'Donnell, Maureen; Poster, Afternoon, Westminster Hall: 70
Okafor, Maria-Theresa C.; Poster, Morning, Westminster Hall: 79
O'Neill, Maura; Poster, Morning, Westminster Hall: 34
Potnis, Pushya; Poster, Afternoon, Westminster Hall: 59
Powell, Kathleen; Poster, Morning, Westminster Hall: 80
Prosser, Ben; Poster, Afternoon, Westminster Hall: 51
Reader, Jocelyn; Oral, Morning, BRB 1-008: 11
Rice, Melissa; Poster, Morning, Westminster Hall: 81
Rice, Karen; Poster, Afternoon, Westminster Hall: 90
Rich, Shayna; Poster, Morning, Westminster Hall: 82
Roche, Renuka; Poster, Afternoon, Westminster Hall: 60
Rogers, Hobart; Poster, Morning, Westminster Hall: 35
Scherer, Matthew; Poster, Morning, Westminster Hall: 36
Schwarz, Jaclyn; Poster, Morning, Westminster Hall: 20
Smith, Sarice; Poster, Afternoon, Westminster Hall: 52
Song, Wei; Oral, Afternoon, SSW/Law Building 302: 44
Stiltz, Jennifer; Oral, Morning, SSW/Law Building C-001: 6
Tang, Ying; Poster, Morning, Westminster Hall: 83
Tseng, I-Chu; Poster, Afternoon, Westminster Hall: 71
Valluri, Satish; Poster, Morning, Westminster Hall: 84
Vargas, Noelle; Oral, Afternoon, SSW/Law Building 302: 45
Wang, Ying; Oral, Morning, BRB 1-008: 12
Wei, Yu-Jung; Poster, Afternoon, Westminster Hall: 91
Weiss, Michele; Poster, Afternoon, Westminster Hall: 61
West, Abby; Poster, Morning, Westminster Hall: 37
Wooten, Nikki; Oral, Morning, SSW/Law Building 519: 76
Wright, Christopher; Oral, Morning, BRB 1-008: 13
Wright, Nathan; Poster, Afternoon, Westminster Hall: 62
Yoon, Jennifer; Poster, Morning, Westminster Hall: 21
Zarabi, Bahar; Poster, Morning, Westminster Hall: 30
Zheng, Xiaowan; Poster, Morning, Westminster Hall: 22
Zhu, Xiao; Poster, Afternoon, Westminster Hall: 53
GRADUATE RESEARCH CONFERENCE
THURSDAY, APRIL 3, 2008
52
GRADUATE RESEARCH CONFERENCE
THURSDAY, APRIL 3, 2008
53