Comparative Medicine
Volume 53(4)
Aspects of common marmoset basic biology and life history important for biomedical
research 339-350
This article is an excellent summary of basic biology for captive common marmosets
(Callithrix jaccus). Callitrichids are a group pf New World Monkeys that includes the
genera of Callithrix (marmosets) and sanguinus (tamarins). Marmosets, and their close
relatives, pygmy marmosets, tamarins and Goeld's monkeys, all belong to the six-genera
family of the Callitrichidae. The common marmoset is considered as an "anchor" species
within the Callitrichidae in terms of molecular phylogeny.
Marmosets exhibit physilogical and functional defferences relatives to humans to a much
greater degree than Old World primates
This anthropoids, New World primate matures by 18 months to two years of age, produces
the next generation of offspring by three years of age. Laboratory-bred marmosets do not
harbor pathogens of concern to human health such as Herpes B found in Asian macaques.
Marmosets in captivity are plagued intermittently by gastrointestinal disorders. It is not
clear whether the GI disorders are related to infectious pathogens or to an incomplete
understanding of their GI function and dietary needs.
Marmosets exhibit a variety of mating systems in the wild, the presence of more than a
single breeding female may be atypical, suggesting that the highly successful laboratory
housing of monogamous male-female pairs to form stable breeding groups may be closer
to the norm in free-living groups than was previously considered. Male marmosets and
older offspring exhibit an exceptional degree of care for newborns, which is associated
with elevated circulating levels of prolactin. In captive and free-living groups of common
marmosets, usually only a single dominant male and female breed and all group members
aid in rearing the infants born to dominant pair. This cooperative breeding system of
common marmosets may also be supported by inhibition of sexual behavior and
neuroendocrine inhibition of ovulation in subordinate daughters. Daughters do not engage
in sexual behavior with their biological fathers, but most do so with an unrelated male that
has been introduced after their biological father has died or has been removed.
Marmoset embryos (2-3 pregnancy ) are relatively tardy, compared to macaques and
humans. Marmosets embryos establish vascular anastomoses between their placentae and
share a common chorionic cavity by day 30 of gestation.
Marmosets exhibit extremely high circulating cortisol levels and hyper-functional
hypothalamic -pituitary-adrenal axis. Marmosets the LH hormone receptor deletion
resulting in greatly reduced LH action without impaired CG action.
Marmosets in captivity require daily supplements of large quantities of Vitamin D to
prevent bone loss.
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Take home message:
Marmosets in captivity are plagued intermittently by gastrointestinal disorders. Reason not
clear.
Cooperative breeding system of common marmosets may also be supported by inhibition
of sexual behavior and neuroendocrine inhibition of ovulation in subordinate daughters.
Marmosets exhibit extremely high circulating cortisol levels and hyper-functional
hypothalamic -pituitary-adrenal axis.(No pathophysioloy associated with is condition)
Marmosets, the LH hormone receptor deletion resulting in greatly reduced LH action
without impaired CG action.
Marmosets in captivity require daily supplements of large quantities of Vitamin D3 and C.
No questions provided
Husbandry, handling, and nutrition for marmosets 351-359
This article is an excellent summary of colony management and nutritional requirements
for captive common marmosets (Callithrix jaccus). Callitrichids are a group of New
World Monkeys that includes the genera of Callithrix (marmosets) and Sanguinus
(tamarins). These genera differ slightly in husbandry, handling, and nutrition.
For primary housing, the minimal recommended cage size for Group 1 primates (< 1 kg)
is 0.5 m height and 0.144 m3 floor space. These animals also need nest boxes, perching
branches, and mesh walls of small grid size (e.g. ½ x ½ or 1x 1-in). A cage floor of small
mesh allows feces and urine to go through, but catches large food items for further
ingestion. Cages should be relatively tall in relation to available floor space. Nest boxes,
preferentially made of Lexan, can double as capture-and-transport boxes. Manual restraint
of marmosets is possible due to their small size. Marmosets should be permanently
identified by tattoos on the thigh or abdomen, once the growth process has slowed.
Marmosets are omnivores and have a shorter gut passage time than anthropoids.
Nutritional requirements for marmosets are unique due to high energy requirements, an
increased need for vitamin D3 (due to lack of ultraviolet B and metabolism), and the need
for vitamin C supplementation, as in all NHP’s. Although commercial diets can provide all
of the nutritional requirements, marmosets need variety in their diet. A cafeteria-style diet
includes: New world biscuits, canned marmoset food, and supplementation with other
foods to provide a high protein, high fat, and vitamins. Foods such as eggs, mealworms,
beans, bananas, grapes, apples and oranges should be used to provide the appropriate
supplementation and food enrichment.
QUESTIONS:
1. The recommended method for permanent identification of marmosets is
a) dye marking ear tufts
b) patterns of tail shaving
c) tattoos on thigh or abdomen
d) chain collar with number or name
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2.
a)
b)
c)
d)
3)
Cages for marmosets should be
wider than they are high
longer than they are wide
higher than they are wide
wider than they are long
What is the best type of material to use for a nest box for marmosets?
a) Wood
b) Stainless steel
c) Lexan plexiglass (polcarbonate)
4) Unsedated procedures can be performed on marmosets restrained
a) by a gloved or ungloved hand
b) in a transport container
c) in a standard primate chair
d) in a PVC tube
5) In nature, callitrichids are
a) carnivorous
b) insectivorous
c) gummivorous
d) omnivorous
e) folivorous
6) Energy requirements in callitrichids are high because of
a) metabolic costs
b) reproductive potential
c) small size
d) short gut passage times
e) all of the above
7) Captive diets of marmosets must be higher than anthropoids in
a) protein
b) Vitamin D3
c) Vitamin C
d) Vitamin E
e) a and b
f) b and c
g) c and d
8) A good diet for captive marmosets consists of
a) Canned Marmoset diet (ZuPreem)
b) A High Protein New World biscuit (Harlan)
c) High Protein supplements (eggs, meal worms)
d) Fresh fruits (bananas, grapes, apples)
e) Cafeteria-style diet (all of the above)
ANSWERS:
1) c, 2) c, 3) c 4) a, 5) d, 6) e, 7) f, 8) e
Sample collection and restraint techniques used for common marmosets (Callithrix
jacchus) 360-363
CM 53(4)
As the common marmoset is used for a wide range of research applications
(neuroendocrinology, reproductive biology, neuroscience, behavioral research, infectious
disease and drug development), assorted techniques for sample collection have been
developed. Due to its small size, there is a limit to sample collection. For example, it is
recommended that no more than 15% of the total blood volume be collected over a 30 day
period (animals range in size from 300 to 400 grams). Alternative samples include urine,
feces and scent markings. The article briefly describes various methods for sample
collection in restrained and unrestrained animals. It also briefly describes restraint of
animals for PET and functional MRI studies. Interestingly, for fMRI, animals are sedated,
restrained and then sedation is reversed with animals remaining in place for 2-3 hours for
imaging.
Questions:
1. Name one draw back to use of the common marmoset in research. One benefit.
2. What methods can be used for blood sampling in this species?
Answers:
1. It's small size limits sample size and may present technical challenges for acquisition of
samples. Benefit is that it is easy to adapt to restraint devices of many types for study
purposes.
2. Femoral vein single samples in awake restrained animals. Indwelling femoral or
jugular vein catheters. Indwelling femoral catheters can be used or up to 2-3 hours while
indwelling jugular catheters may be used for sampling for many hours while the animal is
restrained but able to move to a variety of positions. Surgically implanted ports. Sampling
can occur over days.
Reproduction in captive common marmosets (Callithrix jacchus) 364-368
Summary:
Database for the information provided in the overview was collected from 5
institutions totalling 62.2 years with a colony, 479 known-age dames, and 3714 individual
marmosets.
Reproductive History
-typically sexual maturity (motile spermatozoa or ovulation) around 12-13
months
-first conception
-group housing of females suppresses ovulation and appears to be mediated through
changes in the pituitary gland or hypothalamus
-average gestation was 143-144 days
-confirmation of pregnancy best confirmed with detection of steroid metabolites in the
urine or palpating uterine dimensions.
Endocrinologic tests (human or Old World) work poorly.
-delivery date can be accurately determined within 3 days with a crown-rump
measurement taken between 60-95 days and compared against standard prenatal growth
curves.
-twins were most common, triplets or quads made up more than a third of the litters though
-in triplet litters, motor skill scores on day 1 are a better predictor of survival than body
weight
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-postpartum ovulation in marmosets often results in conception and delivery
-pregnancy loss is common among marmosets
-highest percentage lost in days 0-50 (36.1%)
-max life span for marmosets in captivity is around 15 years, however mean for dams was
5.99 years
-therefore only about 5 litters during a dams reproductive life Lactation and weaning
-lactation can last between 65-90 days. Data suggests that after 60 days milk produced is
minimal
-weaning begins around week 4
-infants are physically transported by the mother, father and other group members
-transfer is preceded by harassment (nipping at hands, feet and tail) and in the extreme are
considered abuse
Housing for breeding
-housing in pairs is recommended for successful breeding and even as a mated pair with
older offspring present since they all partake in raising infants
Common problem
-high rate of pregnancy loss
-believed to be less a pathological problem than a way to control reproductive investment
-high infant death rates 25-40% of infants lost before weaning
Contrasts from tamarins
-tamarin (genus Saguinus)
-range of litter size is the same but average is less
-life spans and consequently reproductive lifespans are longer than marmosets
-post-partum estrus not as likely to conceive
-longer inter-birth intervals
Questions
1. T/F Group housing of females will suppress ovulation?
2. What are the primary problem with marmoset production?
3. What is the genus of the marmoset? tamarin?
4. T/F Only the mother partakes in carrying infants?
5. What is the average gestation length for marmosets?
Answers
1. T
2. High pregnancy loss and infant death rates.
3. Callithrix. Saguinus.
4. F
5. 143-144 days.
Clinical care and diseases of the common marmoset (Callithrix jacchus) 369-382
The common marmoset (Callithrix jacchus) has figured prominently in infectious disease
and neuroscience research programs. The species' small size, ease of handling, prolific
breeding in captivity, and low maintenance cost make them a valuable research animal.
Clinical Care of the Common Marmoset
Clinical Procedures.
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Phlebotomy can be performed using the femoral vein and a 25-gauge needle and three
milliliter syringe. Small blood samples (200-300 ul) may be obtained from the saphenous
vein. Fluid volumes equivalent to three to four percent of the body weight may be
administered subcutaneously in four to five sites over the dorsal aspect of the thorax or
ventral abdomen. Due to their small size, endoscopic biopsy of the small intestine of the
marmoset has not been possible.
Marmosets are extremely sensitive to physical restraint, which can have substantial
effects on clinical values such as heart and respiratory rates, temperature, and blood
pressure. Short- and long-term changes in body weight are perhaps the most critical trends
in evaluating individual animals during the diagnosis and treatment. Weight
measurements are a useful tool, specifically if observed over a period, as they are often an
early indicator of inflammatory bowel disease (IBD) or other debilitating diseases.
Transmission of Mycobacterium tuberculosis from human contacts poses a
substantial risk to marmoset colonies. TB testing consists of intradermal injection of a
minute volume of old mammalian tuberculin (0.05 ml) into the palpebrum. The tests are
examined at 24, 48, and 72 h on the basis of the following criteria:
Grade 1: slight bruising of the palpebrum
Grade 2: erythema of the palpebrum without swelling
Grade 3: variable degree of erythema, with minimal swelling
Grade 4: obvious swelling, with drooping of the eyelid and erythema
Grade 5: marked swelling and/or necrosis of the eyelid
** Grades 1 and 2 are considered negative results, 3 is an indeterminate result, 4 and 5 are
considered positive results.
Viral Diseases.
** Interspecies of viral pathogens is of particular importance.
Herpes Viruses (three families - alpha, beta, and gamma).
Common marmosets are not known to harbor an alphaherpesvirus as a spontaneous
viral infection. However, the marmoset is an inadvertent host for herpes and are
susceptible to Herpesvirus tamarinus (alphaherpesvirus that causes a common and
generally asymptomatic infection of squirrel monkeys) and Herpes simplex 1 (HSV-1,
natural host is human where virus causes minimal disease). These 2 viruses may induce a
rapidly progressive disease, with death in 24-72 h. On physical examination, large
coalescing vesicles may be seen on the oral mucosa. The key morphologic feature in
diagnosis is the finding of the multinucleated syncytial cells and intranuclear inclusion
bodies.
Strict separation of common marmosets from squirrel monkeys should be
maintained to prevent transmission.
Two classes of gammaherpesviruses may infect and induce disease in common
marmosets. Herpesvirus saimiri (HVS) and Herpesvirus ateles cause asymptomatic
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infection in their respective natural hosts (squirrel monkey and spider monkey). Crossspecies transmission of HVS and H. ateles to marmosets results in a progressive
lymphoproliferative disorder, similar to Burkitt's lymphoma in humans.
Callitrichine herpesvirus 3 (gamma) is an indigenous lymphocryptovirus in
common marmosets that can induce malignant lymphoma in some animals while others
remain unaffected.
Lymphocytic choriomeningitis virus (LCMV).
LCMV is the etiologic agent for callithricid hepatitis and is responsible for high
morbidity and mortality in numerous New World Species, including common marmosets.
Virus may be introduced to colony by wild rodents and through practice of feeding
neonatal laboratory mice. Prevention should be directed at controlling wild rodents in
facility and screening of food source rodents.
Parainfluenza viruses (Genus Paramyxovirus).
Epizootics in callitrichidae likely result from transmission from human handlers.
In most cases, animals will spontaneously recover.
Measles virus (Genus Morbillivirus).
Measles virus infection is often initiated through contact with infected human
handlers. In callitrichids, the characteristic exanthema is often absent and the virus
frequently targets the gastrointestinal tract. Mortality may approach 100%.
Bacterial Diseases.
Enteropathogenic Escherichia coli (EPEC).
Diarrhea in captive marmoset colonies is commonly caused by gram-negative
bacillus, EPEC.
Marmoset isolates should be considered to have high zoonotic potential (hemolytic uremic
syndrome in humans). Asymptomatic carriers are common. In affected animals, the
clinical disease ranges from acute hemorrhagic diarrhea to chronic progressive diarrhea.
Bordetella bronchiseptica.
Can be spread rapidly by aerosol transmission. Bilateral mucopurulent nasal
discharge may be first clinical sign noted. Death may occur without any preceding clinical
signs of infection.
Klebsiella pneumonia.
Can result in substantial colony morbidity and mortality. At necropsy, find diffuse
enteritis and/or pneumonia. Antemortem diagnosis is rarely attained due to acute nature of
disease.
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Parasitic Diseases.
Giardiasis.
Flagellated protozoans that are transmitted by the fecal-oral route and have
zoonotic potential. Clinical signs include diarrhea, with or without blood, rectal prolapse,
lethargy and dehydration.
Animals may harbor the organism and intermittently shed it and not manifest signs of
disease.
A rapid fecal antigen ELISA is available for diagnosis.
Cryptosporidium parvum.
Potentially zoonotic protozoa that is transmitted by the fecal-oral route. Possible
sources of infection include drinking water and animal-animal transmission. In addition,
cockroaches and houseflies have been implicated as potential vectors. Disease can vary
from being asymptomatic in immunocompetent marmosets to profuse, watery diarrhea in
younger animals.
Toxoplasma gondii.
New World monkeys are particular susceptible to this protozoan parasite. In most
instances, infection results in death. The definitive host, Felidae, passes unsporulated
oocysts in the feces. The oocysts become infective after sporulation in the environment.
Infection in NHP results after exposure to sporulated oocysts shed in feline feces and
spread by insects or cockroaches or by ingestion of rodents containing tissue cysts.
Clinical signs in marmosets include weakness, respiratory distress, and death. The main
control feature is the minimize exposure to cat feces. Attempts must be made to control
insect populations, and the use of dedicated equipment for each species is recommended.
Trichospirura leptostoma.
A pancreatic spiruroid nematode of the common marmoset who become infected
through ingestion of common cockroaches, which serve as the intermediate host. This
nematode has been implicated as the cause of marmoset "wasting disease" with clinical
signs of emaciation despite normal appetite, muscular weakness and ataxia progressing to
paresis of hindlimbs. Examination of feces for eggs or identification of adult nematodes in
the pancreas on H&E stained sections are used to diagnose disease. Minimizing
intermediate host cockroaches is paramount in controlling and avoiding occurrence of this
disease.
Prostenorchis elegans.
P. elegans is seen grossly as large pseudosegmented parasites attached to the
mucosal surface of the ileum, cecum, and colon. Clinical signs may include diarrhea,
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anorexia, and abdominal distention. The parasites' proboscis penetrates the mucosal
surface invoking a severe granulomatous inflammatory response. Control must be directed
at eliminating cockroaches as the intermediate host.
Gastrointestinal Tract Diseases.
Chronic lymphocytic enteritis (CLE).
The most common GI condition affecting marmosets is chronic IBD, commonly
referred to as "marmoset wasting disease". Hallmark signs of CLE are failure to thrive in
juvenile animals and progressive weight loss in adults. Diarrhea is intermittent.
Histologically, changes in cellular architecture result in a malabsorption/maldigestion
syndrome.
Systemic amyloidosis.
Protein folding disorder that results in a beta-pleated sheet protein structure that is
deposited in major organs of the body. Clinical signs are lethargy and weight loss with
hepatomegaly. Congo red staining for birefringence can confirm presence of amyloid.
GI tract lymphoma.
A frequent neoplastic condition of common marmosets. May be associated with
Callithricine herpesvirus 3. Clinical signs are nonspecific - weight loss, anorexia,
depression. Thickening of the small intestine and enlarged lymph nodes may be palpable.
SI carcinoma.
Described as adenocarcinoma with a mucinous or diffuse pattern affecting the
duodenum and/or proximal portion of the jejunum. Cause is unknown. Incidence up to
8.1% seen at the New England Primate Resource Center.
Tooth root abscess.
Canine tooth is the most common tooth affected. Large swelling on lateral aspect of
face ventral to the eye is most common clinical sign.
Cardiovascular Disease.
Femoral artery hematoma.
During phlebotomy, inadvertently drawing blood from femoral artery rather than
vein. Hematoma is typically noted as a large swelling on the medial aspect of the
quadriceps muscle. If hemorrhage is severe, cardiovascular shock may occur.
Metabolic bone disease (MBD).
Marmosets have an unusually high requirement for vitamin D3 (the active form of
vitamin D). Disease has been seen when animals were fed diets with improper calcium-toCM 53(4)
phosphorus ratio or inadequate vitamin D3, or inadequate exposure to UV, resulting in
secondary hyperparathyroidism. In juveniles, rickets develops. In adults, osteomalacia
results. Pathologic fractures and bone demineralization are typical. Treatment requires
salmon calcitonin combined with injectable vitamin D3, injectable and oral calcium
supplementation.
Questions:
1. What is the genus and species for the common marmoset?
2. The adult stage nematode of Trichospirura leptostoma can be found in which organ?
a) small intestine
b) pancreas
c) liver
d) heart
e) kidney
Answers:
1. Callithrix jacchus
2. B
Marmoset models commonly used in biomedical research 383-392
In recent years, use of nonhuman primates has increased in biomedical research, while at
the same time the supply of these animals has been unable to meet the demand leading to
long waiting times to obtain animals for studies. Most researchers have been accustomed
to using macaques * in particular Rhesus (Macaca mulatta) and Cynomolgus (Macaca
fascicularis). In this overview, Dr. Mansfield discusses the Common Marmoset (Callithrix
jacchus) as a possible animal model along with the advantages and disadvantages of this
species. Note that the Marmoset is a new world species while the Macaques are old world
species. Advantages of the Common Marmoset: · Small size, therefore less space needed
for housing and group housing much easier to provide. · Breed well in captivity with
maturity by 18 months of age. · Lower feeding and caging costs than larger primates · Not
a carrier of Herpes B virus * enhanced biosafety · Less destructive of its environment ·
Lower purchase price than macaques · Less drug needed for pharmacological studies, or
for dosing in other studies · Twinning with chimerism between twins non-identical twins
Disadvantages of the Common Marmoset: · Cost is relative; less than macaques but still
much higher than rodents · Small size makes some techniques more difficult to perform ·
Amount of blood available for test samples smaller · Less studies than for macaques leads
to less comparative literature and less tools developed for use with these animals. ·
Immunohistochemistry, Microarray technology, and other tools less developed for these
species * but many human reagents and antibodies can be used. New World vs. Old World
Nonhuman primates Platyrrihines * new world monkeys o Cebidae and Callitrichidae,
many species o Adapted to a neotropical environment o Diet and disease susceptibilities
differ from old world species * this is both an advantage and disadvantage Catarrhines *
old world monkeys o Cercopithecidae most commonly used o More diseases shared or
transmissible with humans o Wide variety of home environments from snow to tropical A
discussion of the uses of Common Marmosets in research follows. I will list the primary
topics here, and ask that you read the article for greater detail. Primary areas in which these
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animals have been used include: Infectious Diseases, Neuroscience, Toxicology and Drug
Development, Reproductive Biology, and Behavioral Research. Infectious Disease Studies:
Unique susceptibility to several herpesviruses has been an advantage *
gammaherpesviruses such as Epstein Barr virus and H. saimiri, and alphaherpesviruses
such as Herpes simplex virus. These are used in studies of viral oncogenesis and persistent
viral infection. Also used with several hepatitis viruses and have a GB virus which is a
model for Hepatitis C (usually Chimps are the Hepatitis C model). Neuroscience: Cerebral
vascular disease (stroke), tardive dyskinesia, multiple sclerosis (experimental allergic
encephalitis or EAE is a model of human MS), neurodegenerative diseases (Parkinson's
and Huntington's diseases), Alzheimer's Disease, and in normal neurophysiology. Note that
the chimeric immune systems of marmoset twins or triplets is very useful in studies of T
cells and epitope modeling. Toxicology and Drug Development: Used in drug safety
assessment and toxicology particularly in Europe. Closer relation to humans than rodents,
dogs, etc., yet shorter study times and amounts of chemical needed for testing. Useful in
teratologic studies and other reproductive toxicology (rodents often have quite different
effects than primates). Reproductive Biology: Luteal regression, contraceptive
development (immunocontraception), etc. Behavioral Studies: Can be housed in family
groups so normal behavior easier to observe. Only the dominant female reproduces in a
group * how this occurs helps understand many social and endocrine factors. Also used as
a model for anxiety and stress, and early deprivation effects later in life. In conclusion, the
author reminds us that the Common Marmoset is widely used, and may be used even more
in the future.
Questions:
1. The Common Marmoset is native to what area?
a. Africa b. South America
c. India d. Viet Nam
2. T or F Common Marmosets often give birth to Identical Twins.
3. List three areas in which Common Marmosets have been used for biomedical research.
Answers:
1. B These animals are native to eastern Brazil (Baboons * Africa, Macaques * India and
Viet Nam and other parts of Asia)
2. F The twins are non-identical, but there is mixing of the blood during development so
the bone marrow shows chimerism.
3. Infectious Disease, Neuroscience, Toxicology and Drug Development, Reproductive
biology, Behavior.
Study of low temperature (4C) transport of mouse two-cell embryos enclosed in oviducts
393-396
Alternatives methods for shipping mice to other research institutions were explored.
Currently either live mice are shipped or embryos are cryogenically frozen, shipped,
thawed and undergo embryo transfer. The lab looked at the development rate of 36 hr.
chilled two-cell embryos both in vitro (to hatched blastocyst stage) or in vitro (to live
birth). Just over 2/3 of two-cell embryos kept at 4o C for 36 hours developed to the
hatched blastocyst stage when cultured post-chilling and 20% developed to live young
after embryo transfer in the lab. When oviducts containing two-cell stage embryos were
chilled and shipped to another lab for embryo transfer, approximately 30% of the flushed
embryos developed and were born live. Extending the chill time to 48 hours and beyond
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dropped the viability of embryos to about 1/3 of those chilled up to 36 hours (although
another report apparently had good viability with embryos chilled for 48 hrs).
This method appears to be a successful alternative to the freezing of in vivo derived
embryos, which requires not only sacrifice of the donor and collection of oviducts, but
specialized freezing, thawing and shipping equipment and expertise. This method
simplifies things by combining techniques common to many mouse labs (breeding, oviduct
removal and embryo
transfer) with shipment in styrofoam boxes with ice, enabling many more
institutions to 'trade' animals without going to great expense.
No questions.
Susceptibility of irradiated B6D2F1/J mice to Klebsiella pneumoniae administered
intratracheally: a pulmonary infection model in an immunocompromised host 397-403
OverviewRadiation exposure can induce an immunocompromised condition that predisposes an
animal to infection by an opportunistic pathogen. In human patients, these infections can
be difficult to treat as has been seen with individuals exposed to radiation at Hiroshima,
Nagasaki, and Chernobyl.
Klebsiella pneumonia is a gram-negative rod (family Enterobacteriaceae) that in
humans is the leading cause of nosocosomial and community-acquired gram-negative
bacterial pneumonias. Without treatment, infection with K. pneumoniae results in high
mortality.
This paper details an experimental model of induced pneumonia that was
developed in 60-Co gamma-photon-irradiated B6D2F1/J mice infected with K.
pneumoniae via tracheal instillation. The model is designed for eventual use in evaluating
efficacy of therapeutic agents. The B6D2F1/J strain of hybrid mouse was chosen because
the authors had not previously isolated K. pneumoniae from this strain of mice even after
irradiation. The organism has only been isolated from the strain after purposeful
inoculation. In this strain, mortality occurs with irradiation doses of >7.75 Gray (Gy).
A Gray (Gy) is the International System of Units base unit for absorbed energy.
A Gy equals one joule per kilogram (1 Gy = 1 J/Kg).
Methods and MaterialsTwo experiments were performed. For both experiments, female B6D2F1/J Mice were
given a 0-Gy (sham), 5-Gy, or 7-Gy non-lethal dose of 60-Co gamma-photon radiation
("60" is superscript). Four days after irradiation (which corresponds with decreased white
blood cell concentrations and maximum infection susceptibility) each group was
anesthetized and intratracheally challenged with one dose of bacteria in serial tenfold
concentrations. Intratracheal instillation utilized the tongue-pull method in which the
solution was placed past the laryngeal folds and deposited mid-trachea. No surgery was
required.
For the first experiment, the survival percentage and number of 340 12- to 14week old female mice randomized over the 3 irradiation groups (0-Gy, 5-Gy, and 7-Gy)
was recorded daily for 30 days post bacterial challenge. Heart blood, lungs, kidney,
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spleen, and liver were cultured postmortem. A regression analysis was performed as part
of a probit analysis. "Probit regression line fits were made to mortality data versus log10
K. pneumoniae dose at the radiation doses of 0, 5, and 7 Gy...In addition to providing a
model for the relationship of mortality to log10 of K. pneumoniae dose, these probit lines
were used to assess a dose-modifying factor (DMF)." The DMF as used as "the factor
measuring the ratio of the K. pneumoniae dose at 0 Gy to the K. pneumoniae dose at 5 Gy
or 7 Gy that would induce the same mortality."
For the second experiment, 90 15-week-old female mice randomized over the 3
irradiation groups were infected with a bacterial dose inducing 85% mortality over 30 days
for each radiation dose. Animals were euthanized at 5, 7, and 9 days post-irradiation.
Heart blood, lung, and spleen were cultured. Heart, lungs, spleen, kidney, and liver were
examined by histopathology.
ResultsExperiment 1: Bacterial CFU values producing 50% mortality within 30 days for each of
the irradiation doses were found. No significant differences were found in probit line
slopes. The 5-Gy probit line did not differ significantly from the 0-Gy probit line but the
7-Gy probit line differed significantly form the 0-Gy probit. Bacteria was cultured from
the 5 and 7 Gy-irradiated groups indicating that they were bacteremic. Bacilli were
diffusely present in the lungs. Moderate to severe lymphoid depletion was noted in the
spleen.
Experiment 2: Histopathology revealed the following:
1) bronchopneumonia affecting one to multiple lobes of the lungs;
2) lymphoid depletion of the spleen, thymus, and lymph nodes in 5- and 7-Gy
groups;
3) hematopoietic elements were depleted from splenic red pulp in 5- and 7-Gy groups;
4) inflammatory cellular reaction was present in the lungs in varying amounts (most with
0-Gy and least with 7-Gy);
5) extracellular gram-negative bacilli were prominent at d5 and d7 in 5- and 7-Gy groups.
By d7, these animals had bacterial emboli in the heart, lungs, spleen, kidneys, and liver.
This was not seen in the 0-Gy group.
DiscussionIntratracheal instillation of K. pneumoniae has an advantage over surgical instillation of
the bacteria in that it does not induce surgical stress on an animal and does not require
wound healing which is impaired in irradiated mice. However, this method does require
the skill of performing accurate intratracheal instillations.
A best-fit curve was produced for predicting the intratracheal dose of K.
pneumoniae required for 50% mortality. This illustrated that susceptibility of irradiated
mice to bacterial infection varies with the dose of irradiation.
"Future applications of this model include understanding the pathogenesis of
bacteremia and developing effective treatment regimens with antimicrobial agents and
immunomodulators to improve survival of irradiated surrogate animals, especially as
bacterial infections become increasingly more difficult to treat with antimicrobial agents."
QUESTIONS:
CM 53(4)
1. What is the International System of Units base unit for absorbed energy?
2. this unit is equal to 1 ? per kilogram?
3. In irradiated animals, what at is one advantage of intratracheal instillation of substances
by the tongue-pull method when compared to surgical instillation?
4. Why is K. pneumoniae ideal for modeling pulmonary bacterial infections?
5. T/F: Susceptibility of irradiated mice to bacterial infection varies with the dose of
irradiation?
ANSWERS:
1. a Gray (Gy)
2. 1 Gy = 1 joule per kilogram
3. the tongue-pull method does not require wound healing which is impaired in irradiated
animals
4. it is a leading cause of nosocomial and community-acquired gram-negative bacterial
pneumonia.
5. True
Qualitative and quantitative differences in normal vaginal flora of conventionally reared
mice, rats, hamsters, rabbits, and dogs 404-412
SUMMARY:
The article discusses a comparison of normal vaginal microflora during different stages of
the estrous cycle between several lab animal species (mice, rats, hamsters, rabbits and
dogs) utilizing the Mitsuoka procedure which is generally used for evaluating intestinal
flora. Previous reports have studied vaginal flora of many species but no direct
comparison have been made and it would be difficult to conclude differences between
species as different testing methods (i.e., lavage, swab or loop methods) were used in these
reports.
The following were the animals used in this particular study:
Seven, 12 week old, virgin, ICR/Kud,
Seven, 12 week old, virgin, Wistar/Siz rats,
Eight, 9 week old, virgin, Syrian hamsters,
Six, 8 months old, virgin, New Zealand White rabbits,
Nine, 12-18 month old, virgin, Beagle dogs
The mice, rats and hamsters were housed under SPF conditions meaning they were
maintained on a laminar flow bench, drinking water was filtered and the wood chips were
sterilized. The rabbits and dogs were housed in the lab, drinking water was filtered and the
room was cleaned daily. Vaginal specimens were taken using sterile lavage procedures:
once a day for 5 days in mice and rats, once a day for 4 days in hamsters, 3 times every
two days for 1 week in rabbits, and once a month for 11 months in dogs. The Mitsuoka's
procedure was used to analyze the samples. The technique
consists of filling the sample tube immediately with 100% CO2 gas, placing it in an
anaerobic glove chamber, mixing it, preparing 100-fold dilutions with anaerobic diluents
and plating on non-selective and selective agars. Should see article for very brief
summaries of 14 selective agars.Bacterial groups were then identified using normal
microbiology techniques.
CM 53(4)
It was found that the bacterial load was highest during estrus in the mice, rats, hamsters
and dogs. The predominant bacteria in each species was discovered as the following: mice
was streptococcus, rats was gram (-) rods, streptococcus and Bacteroidaceae, hamsters was
gram (-) rods, Bacteroidaceae and gram (+) anaerobic cocci, in dogs was Bacteroidaceae.
Also found in mice was that there were a greater number of aerobes than anaerobes, in rats
and dogs there was an equal amount of aerobes and anaerobes, and in hamsters there were
a greater number of anaerobes than aerobes. In rabbits there was an infrequent number of
bacteria found (streptococcus and Bacteroidaceae). The article concludes that number and
prevalence of vaginal flora is influenced by the estrous cycle and that the increased mucus
secretions from glands in the cervix during estrus provides a mucopolysaccharid which
serves as a culture medium allowing for flora proliferation.
QUESTIONS:
1. Compared to the vaginal flora during estrus which has between 3-5.5bacterial groups,
the intestinal flora comprise of:
A. 4-7 bacterial groups
B. 5-8 bacterial groups
C. 8-11 bacterial groups
D. 9-12 bacterial groups
E. 10-13 bacterial groups
2. Which of the following species most closely resembles the vaginal flora in humans:
A. Mice
B. Rats
C. Hamsters
D. Rabbits
E. Dogs
3. True or False: Rabbits do not have cyclic reproductive stages.
ANSWERS:
1. E. 10-13 bacterial groups; predominant groups in the normal intestinal flora of mice,
rats, hamsters, rabbits and dogs are anaerobic bacteria (Bacteroidaceae, gram (+) anaerobic
rods, and lactobacilli).
2. C. Hamsters would be in that the flora is dominated by anaerobes, the total number of
bacteria is high and the composition is the most complex which is all similar to humans.
Note however studying a lactobacilli vaginitis (the dominant flora in humans) would not be
appropriate in hamsters as their numbers are very low. Chimpanzee however demonstrate
lactobacilli as the dominant flora and would therefore be an adequate model of lactobacilli
vaginitis.
3. True: Rabbits are usually in a precoital status in the laboratory
which is comparable to diestrus in mice, rats and hamsters and to anestrus in dogs.
Normal hematologic and serum clinical chemistry values for captive chimpanzees (Pan
troglodytes) 413-423
Summary:Longitudinal study of chimpanzee hematology and serum chemistry values. Age
and sex effects are seen in various values. Overall, comparison to human reference ranges
were very similar. Study taken on as historically lab animal veterinarians have often relied
CM 53(4)
on human reference ranges. Published literature is controversial regarding adequacy of this
comparison and numerous discrepancies have been noted
M&M:

All animals were from the Primate Foundation of Arizona.

Included 86 chimps (38 male and 48 female)

Ranged in age from infants to aged

All were free of hepatitis and HIV

All were fasted and anesthetized with either ketamine or telazol prior to blood
collection

Values were analyzed by age and sex
Discussion:

Authors note that this report is the first step in the development of reliable
chimpanzee reference values. Suggest a collaborative study between animal in
different facilities and that the next study use unanesthetized animal after training
for blood collection

This study did not replicate results of many published studies that demonstrated
significant differences between human and chimp values

Found males had higher values for red blood cells, hematocrit, and hemoglobin
than females

Found that MCH, MCV, total protein, neutrophils, creatinine, globulin,
triglyceride, GGT, ALT, CK and direct bilirubin increase with age

Found that anion gap, cholesterol, ionized calcium, and phosphorus decrease with
age

Suggest wariness in using human reference values for young animals
Questions:
1.
T/F Using human reference ranges for hematologic parameters in infant
chimpanzees is recommended
2. ____________________ has been found to decrease with age in chimpanzees
a. Total protein
b. Creatinine
c. Phosphorus
d. Creatinine Kinase
Answers:
1.
F
2.
c
Spontaneous pituitary abnormalities and mammary hyperplasia in FVB/NCr mice:
CM 53(4)
implications for mouse modeling 424-432
The FVB/N strain of mice has been widely used for the generation of transgenic mouse
models. The advantages from using this strain of mice include their inbreed status, high
fertility, large size of the pronuclei in fertilized zygotes that facilitates injection of the
transgene, and good survival of embryos following injection. This laboratory has noted in
there experiments working with the FVB mouse strain that the mammary gland of wildtype virgin females (FVB/NCr) mice have frequent morphologic and histologic appearance
of glands seen in pregnant mice.
Materials and Methods
FVB/NCr ere used in this study. Pathologic examination of pituitary and mammary glands
were evaluated at selected time points. Tissue sections were stained with haematoxylin
and eosin. Immunohistochemical analysis and radioimmunoassay for prolactin was
performed on formalin-fixed pituitary gland sections.
Results
Inappropriate mammary gland differentiations in virgin FVB/NCr mice were noted.
Mammary glands for older control virgin female mice had glandular morphology similar to
those see in mid-gestation pregnant animals. The glands from these virgin control mice
showed lobular hyperplasia (also known as "functional hyperplasia without atypia").
Please note Figures 1A-1F on page 426.
High prevalence of proliferative lesions in the pituitary gland was
also noted in these mice. In a cohort of virgin female FVB/NCr female mice aged 18 to 23
months, 71% had pituitary gland abnormalities (15/21). Hyperplasia of the pars distalis
was seen in 11/21 (52%) of the mice evaluated with 4/21 (19%) of the mice having
pituitary adenomas. Immunohistochemical staining for prolactin showed where the
proliferative lesions were positive for the hormone. Please note Figures 2 and 3 on page
427. Circulating prolactin levels in virgin FVB/NCr mice approximately 13 months of age
had abnormally high circulating levels of prolactin. Please note that 64% of the mice in
this study by 13 months of age had serum prolactin levels that were more that 2 SD above
the normal mean value for mice (mean normal range is 7.1 ng/ml) [Figure 4 on page 427].
A strong correlation was noted between mammary gland (lobular-alveolar
hyperplasia) and pituitary gland (hyperplasia) histologic features were noted. Please not
Figure 5 on page 428 and Figure 6 on page 429.
Spontaneous mammary tumors in multiparous but not virgin mice were found in
this study. Ina cohort of 6 female FVB/NCr mice, aged 18 to 22 months, which were
multiparous breeders on a continuous breeding protocol 4/6 (67%), had palpable mammary
tumors. Please note Figure 7 and its legend on page 429.
Conclusion
FVB/NCr mouse substrain has an unusually high prevalence of prolactin-secreting
pituitary lesions at an early age. This feature has positive and negative implications for the
use of the FVB/NCr mouse as an animal model for pituitary and mammary gland tumors.
The authors state that since prolactin also has effects on other organs, immune fuction, and
behavior, additional prolactin-driven phenotypes may be anticipated in aged FVB/NCr
mice and other FVB/N mouse substrains.
CM 53(4)
Questions:
1.
What are some common uses for the FVB/N mouse strain in biomedical
research?
2.
True or False: Virgin FVB/NCr mice frequently have mammary glands that
exhibit functional hyperplasia without atypia.
3.
True or False: Virgin FVB/NCr mice frequently had serum prolactin levels that
were more than 2 standard deviations (SD) above the reported mean of mice.
4.
True or False: Virgin FVB/NCr mice between 18-23 months of age show a strong
correlation between mammary gland (lobular-alveolar hyperplasia) and pituitary gland
(hyperplasia).
Answers:
1.
The advantages from using this strain of mice include their inbreed status, high
fertility, large size of the pronuclei in fertilized zygotes that facilitates injection of the
transgene, and good survival of embryos following injection.
2.
True
3.
True
4.
True
Persistent mammary hyperplasia in FVB/N mice 433-438
The inbred FVB/N mouse strain is widely used for creating transgenic mice. Over the past
decade, persistent mammary hyperplasia has been detected in many multiparous FVB/N
female mice sent to the University of California, Davis (UCD) Mutant Mouse Pathology
Laboratory (MMPL) by a number of different laboratories. However, the experimental
details concerning most specimens were not always available. To confirm these empiric
findings, experiments were carried out to evaluate the mammary glands of FVB/N mice
under controlled conditions. Persistent mammary hyperplasia that related to parity was
found. Weeks after their first to fourth pregnancy, 10 FVB/N female mice from the
Lawrence Berkeley National Laboratory (LBNL) colony were studied and the mammary
glands were evaluated. The percentage of fat pad filled was estimated, using image
analysis. Serum samples and the pituitary gland from other FVB/N mice from the LBNL
were assayed for prolactin concentration. Multiparous FVB/N females consistently had
persistent mammary hyperplasia. Four of seven females in the LBNL colony had
hyperplasia after three pregnancies. A few foci of squamous nodules and sporadic
carcinomas also were observed. Thus, some FVB/N females may have persistent
mammary hyperplasia after three pregnancies without detectable pituitary abnormalities.
Mammary carcinomas also may develop sporadically. These background phenotypes must
be considered when interpreting the effect of genetic manipulation in FVB/N mice.
Materials and Methods
FVB/N mice were used in this study. For historical comparison , 350 FVB wildtype mammary glands were identified and reviewed. In the experimental design, a cohort
of 13 FVB/N females were placed in experimental groups that were either maintained as
nulliparous (n = 3) or bred (n = 10). Mice that were bred were further divided into those
with one, three, four, or five lactations. Complete necropsies were performed, including the
pituitary gland (please see CM (4):424 - 432, 2003). Slides of histologic sections and
whole mounts of mammary glands were made. Tissue sections were stained with
CM 53(4)
haematoxylin & eosin. Images of histological and whole mount sections were processed
and analyzed and the area occupied by epithelium compared to total area of the dissected
fat pad were expressed (fat pad filled, or % fpf).
Results
From historical observations, retired FVB mice breeders often had diffuse
lobuloalveolar mammary hyperplasia, with no evidence of involution. Abnormal
involution has been noted in many breeders but is not a consistent finding. The criteria for
hyperplasia in controls consisted of increased numbers of morphologically normal lobules
in either nulliparous or mice not supporting litters, and that more than 10% fpf was
considered hyperplasia. Review of multiparous wild-type FVB/N females supported
persistent lobuloalveolar hyperplasia in this group. In the experimental group (n = 13),
consistent with previous observations, the first pregnancy was followed by normal
involution, but after three pregnancies, an increasing proportion of mammary gland
samples had persistent hyperplasia, with failure to regress completely. Light microscopy
revealed histological patterns that correspond with those of the whole mounts. The
differences in the recorded % fpf values between the whole mounts and the histological
sections reflected the 2-D vs. 3-D view, thus the % fpf was often higher in the whole
mount evaluation. Whole mount % fpf gland epithelium remnants (epithelial cell filling)
averaged 2.4% for nulliparous, 8.1% for one lactation, 27% after three lactations, 58%
after four lactations, and only 5% after five lactations.
Conclusion
The mouse mammary gland has been used as a model of epithelial cell growth and
differentiation and programmed cell death because these events take place during a normal
pregnancy. In particular, the FVB/N mouse has been used to study involution in
genetically engineered mice. In this study, empirical and experimental data has been
presented to suggest that many FVB/N female me have abnormal patterns of mammary
gland involution, and that persistent mammary hyperplasia is widespread. In one study,
mammary hyperplasia was independent of parity and was associated with an abnormal
pituitary gland, including prolactin-positive hyperplasia and adenomas, and high serum
prolactin concentration. Scattered squamous nodules were found in the mammary glands
of multiparous FVB/N females, and four of the six mammary tumors found during 12
years of mammary gland research were carcinomas with some degree of squamous cell
differentiation.
This study and empirical information from multiple labs suggest that there is a
delayed regression or persistent hyperplasia in multiparous, wild-type FVB females, and
that recognition of this is critical to the design of experiments that use FVB/N mice to
study genetics that might control involution, hyperplasia, and neoplastic progression.
At least three possible causes of persistent hyperplasia should be considered: 1)
pituitary abnormalities, 2) mechanical blockage which will predispose the gland to
hyperplasia, dysplasia, or neoplasia, and 3) genetic defects, either inherent to the strain or
due to engineered alleles.
Interpretation of the mammary gland pathology in genetically engineered FVB/N
mice must take wild-type pathologic changes into account.
Questions:
CM 53(4)
1. The FVB/N mouse strain is used for creating transgenic mice. One research focus
for this mouse strain has been for studies of mammary biology. (True or False)
2. Mammary gland hyperplasia is not a feature of FVB/N wild type controls. (True or
False)
3. Some FVB/N females may have persistent mammary hyperplasia after three
pregnancies with detectable pituitary abnormalities. (True or False)
Answers:
1.
True
2.
False
3.
True
Confirmed persistent mouse hepatitis virus infection and transmission by mice with a
targeted null mutation of tumor necrosis factor to sentinel mice, using short-term exposure
439-443
SUMMARY:
BLUF (bottom line up front) - This paper adds to the evidence that a side-effect of mouse
genetic engineering is the potential for a new line's phenotype to include subtle/inapparent
immune dysfunction that can result in apparent inability to control and eliminate mouse
hepatitis virus (MHV) infection in otherwise apparently normal mice. The mice in this case
are a tumor necrosis factor (TNF) knockout line. The line was confirmed to be persistently
infected and shedding MHV while in quarantine. As little as 24 hours of direct contact
with the infected knockout line led to infection of mouse sentinels.
ABSTRACT - Mouse hepatitis virus (MHV) infection in immunocompetent mice is
typically self limiting, and transmission is short lived. With the recent surge in the
development of genetically engineered mutant mice with alterations in immune system
components, however, MHV clearance may be disrupted. We report confirmed persistent
transmission of MHV from tumor necrosis factor (TNF) knockout mice, B6.129S1Tnftm1Lj (TNF -/-), to nude and immunocompetent sentinel mice over a period of five
months. Infection with MHV was confirmed in nude sentinel mice by use of reverse
transcriptase-polymerase chain reaction (RT-PCR) detection of viral RNA in ascending
colon and feces. The RT-PCR-analyzed specimens recovered from sentinel animals were
sequenced, and 92% homology to the N region of the MHV strain S genome was
documented. In addition, immunocompetent mice had evidence of seroconversion to MHV
infection and RT-PCR-positive fecal and ascending colon specimens after only 24 h of
direct contact with the TNF -/- mice. To the authors' knowledge, this is the first reported
experimental evidence that MHV transmission can occur for several months, from
persistently infected mice to sentinel mice, over a short-term exposure period.
Materials, Methods and Results - B6.129S1-Tnftm1Lj (TNF -/-) from a non-commercial
source were quarantined, despite negative serology results from the originating institution
health quality assurance program. Part of the quarantine husbandry included cage change
in a biosafety cabinet, and disinfection of technicians' gloves with Quatricide between
different quarantine groups. The mice themselves were serologically tested, and four of
five mice were found to be seropositive for MHV. Both athymic nude and CD-1 contact
sentinels subsequently became MHV positive (using RT-PCR on ascending colon and
feces) after as little as 24 hours of direct contact with the quarantine mice, though
transmission was not 100% (some sentinels did not apparently become infected).
CM 53(4)
Discussion - Altering the quarantine husbandry to require gloves change rather than
disinfection between quarantine group husbandry apparently interrupted continued spread
of infection in quarantine. The particular susceptibility to, and inability to clear, MHV
infection of the knock-out line may be related to somewhat reduced IFN-³ production by
their macrophages, and/or somewhat decreased IgG1 and IgG2b in this line.
QUESTIONS:
1.
What virus family does MHV belong to?
2. What does the nomenclature B6.129S1 tell you about a mouse line?
3.
Which of the following applies to mouse hepatitis virus infection in mice?
a)
Infection often is associated with clinical signs.
b)
Infection can be clinically inapparent, and can persist in a variety of
circumstances
c)
Infection is generally persistent.
d)
Immune competent mice have acute, self-limiting infections.
e)
a and c
f)
b and d
ANSWERS:
1. Coronaviridae, which are enveloped single-stranded RNA viruses.
2. This (B6.129S1) is a congenic line, with C57BL/6 as the host strain and 129SvIMJ as
the donor strain.
3. f) b and d.
Source of a micro-nutrient in a semi-synthetic basal diet as a causative factor in inducing
urinary calculi in rats and its inhibition by PSC 833, a potent inhibitor of p-glycoprotein
444
Objectives: To determine the cause of urinary calculi development in Rats being fed a
semi-synthetic basal diet (diet No. 1201101, Dyets Inc).
Case Report:
*
50-day old female Sprague-Dawley rats were injected with a
dose of N-methyl-N-nitrosurea (MNU). 3 weeks later they were exposed to basal diet No.
1201101, Dyets Inc. By 23 weeks, 15 of 26 rats had to be euthanized because they had
become uremic. Urinary calculi were present in the renal pelvis, ureters, and urinary
bladder of these 15 rats. The complete composition of the calculi could not be determined,
but they contained calcium (about 20%), potassium (0.015%), magnesium (0.034%),
sodium (0.38%) and oxalate (28 +/- 10%).
*
122 Male Fischer 344 rats were injected with diethylnitrosamine and fed basal diet
No. 101101. After 9 weeks, 24 were euthanized for displaying signs of uremia. 23 of the
24 had developed urinary calculi.
Experimental Results:
*
MNU treatment was not the contributing factor (30 rats were fed diet 1201101. 15
were treated with MNU, and 15 remained untreated. Both groups developed urinary
calculi at the same rate).
*
Rats fed basal diet containing a Food Chemical Codex (FCC) grade choline
bitartrate developed urinary calculi at a high frequency.
CM 53(4)
*
Rats fed the same basal diet containing the US Pharmocopia grade of choline
bitartrate did not develop urinary calculi.
*
Treatment with PSC delayed the onset of urinary calculi formation and significantly
decreased the incidence of urinary calculi by 50 and 72 percent.
Comments:
*
Other studies have shown that female Sprague-Dawley rats appear more susceptible
to development of renal calculi associated with high-protein diets or alterations in the
calcium-to-phosphate ratio.
*
This group had been using choline bitartrate in the formulation of diet No. 101101
for several years without incident.
*
PSC is an inhibitor of P-glycoprotein. The hypothesis this group was originally
testing is that glycoprotein (Pg, product of mdr 1) is intimately associated with
development of cancer, and agents that inhibit Pgp should, therefore, inhibit such
development.
Conclusions:
*
Contamination or a component(s) used in the preparation of a Food Chemical
Codex (FCC) grade choline bitartrate and not the choline Bitartrate per se was the principal
risk factor contributing to the development of urinary calculi.
*
This case report highlights how something seemingly innocuous as a minor dietary
constituent can have a confounding effect on experimental data, and thereby affect
experimental outcome.
*
PSC and possibly other inhibitors of Pgp can have a protective effect against urinary
calculus formation.
Questions:
1. Which of the following was a causative factor in inducing urinary calculi in rats?
a.
Sex of rat
b.
Strain of rat
c.
Injection with MNU (N-methyl-N-nitrosurea)
d. choline bitartrate
e.
A contaminant or component(s) used in preparation of FCC-grade choline bitartrate
2. Which of the following is associated with in increased incidence of developing renal
calculi in adolescent female Sprague-Dawley rats?
a. low protein diets
b. high protein diets
c. alterations in the calcium-to-phosphate ratio
d. a and c
e. b and c
3. True/False A minor dietary constituent can have a confounding effect on experimental
data.
Answers:
1. e. A contaminant or component(s) used in preparation of FCC-grade choline bitartrate
2. b and c. Both high protein diets and alterations in the calcium-to-phosphate ratio have
been documented
3. True
CM 53(4)