King Saud University
College of Science
Department of Biochemistry
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Chapter 8
Pregnancy Test
Bence-Jones Proteins
17-Keto-Sterods
Professor A. S. Alhomida
1
Relative Size of Human Conceptus
2
Maternal Fetal System
Placenta
1. Connects Fetus and
Mother
2. Transports:
 Nutrients & O2
 Waste products &
CO2 away from fetus.
3. Early Nutrition of Fetus
Due to:
 Trophoblastic
digestion
 Absorption of
nutrients from
endometrial deciduas
3
Gestational Hormones
Ovulation
Parturition
1. Human
chorionicgonadotr
opin (hCG)
2. Human
chorionicsomatom
ammotropin
(hCS; hPL)
3. Estrogens
4. Progesterone
4
Gestational Hormones, Cont’d
5
Human Chorionic Gonadotrophin (hCG)
•
Secretion
1.
It is a glycoprotein hormone produced by the developing placenta
shortly after fertilization and the embryo attaches to the uterine lining
and
It builds up rapidly in pregnant body in the first few days of pregnancy
2.
•
Function
1.
2.
3.
4.
5.
Prevent involution
Stimulate progesterone and estrogen secretion
Prevent menstruation
Promote endometrium growth
Stimulate testosterone
•
Production  development of fetus male sex organs
6
Placental Estrogen
• Secretion
1. Secreted by placental trophoblast
2. Androgen precursors from maternal and fetal adrenal glands
• Function
1. Uterus enlargement
2. Relaxation of pelvic ligaments – more limber for passage of
fetus through birth canal
3. Breast enlargement
4. Growth of breast ductal tissue
7
Progesterone
• Secretion
1. Secreted by corpus luteum and placenta
2. Essential for pregnancy
• Function
1. Development of decidual cells in endometrium for fetal
nutrition
2. Decrease contractility of uterus
3. Prevent spontaneous abortions
4. Ovum development prior to implantation
5. Breast preparation for lactation
8
Human Chorionic
Somatomammotropin (hCS)
•
Function
1. It is a general metabolic hormone
2. Partial development of maternal breasts
3. Effect on metabolism
•
•
•
Decreases maternal glucose usage  for fetal usage
Promotes FFA release from maternal stores  energy for fetus
Weak action on protein deposition; similar to GH
4. It is important for the nutrition of mother and fetus
9
Clinical and Biochemical
Significance of hCG
1. Increased urinary excretion of hCG which occurs in early
pregnancy (early as 10th day of gestation)
2. There are two different pregnancy tests:
•
Biological Test (Aschein-Zondek test) has been replaced
completely by:
•
Immunological Test (home pregnancy test)
10
Home Pregnancy Test
1. It is a colloidal gold/antibody complex based rapid
chromatographic immunoassay for the detection of hCG in
urine
2. hCG can be detected in urine as early as 7 days after
conception
3. hCG concentrations peak at about 9-12 weeks into pregnancy
4. The amount of hCG will vary greatly with gestational age and
between individuals
5. It detects the presences of hCG in urine specimen at the
sensitivity of low concentration
11
Principle of Home Pregnancy Test
1. The hCG Urine dipstick Test consists of a chromatographic
absorbent device and an unique combination of monoclonal
antibodies that selectively detect hCG in test samples with a
high degree of sensitivity
2. Urine migrates through the absorbent area and along the test
membrane
3. hCG present in the specimen is bound by antibody-gold
conjugate forming an antibody-antigen complex
4. The complex is captured by anti-hCG antibody immobilized in
the test zone (T) of the membrane forming a pink-rose band
12
Principle of Home Pregnancy Test,
Cont’d
5.
6.
7.
In the absence of hCG, no line will form in the test zone (T)
While the test line indicates the level of hCG present in the
sample
Another gold conjugate is captured by the antibody
immobilized in the control zone (C) of the membrane
producing pink-rose color band, regardless of the presence or
absence of hCG in the sample
13
Principle of Home Pregnancy Test
•
•
•
•
C: Control zone containing antihCG antibody to give pick-rose
band
T: Test zone containing
antibody-gold conjugate forming
an antibody-antigen complex
with urine hCG to form pick-rose
band
Negative Result: only one pickrose band in C zone will appear
Positive result: two pick-rose
bands will form, one on C and
other is on T zone
14
Home Pregnancy Tests, Cont’d
15
Home Pregnancy Tests, Cont’d
16
Bence-Jones Proteins
1. They represent either the kappa or lambda
immunoglobulin light chains
2. They are most often associated with multiple
myeloma (plasma cell cancer)
3. L chains are over produced by proliferating plasma
cells and released into the blood without combining
with H chains
17
Bence-Jones Proteins, Cont’d
4. They excreted in urine because of their relatively
small size
5. They are precipitated at 60 C and used for diagnosing
multiple myeloma
6. Excretion of BJ proteins in large amounts causes the
tubular cells to become degenerated because of high
levels of BJ reabsorbed
18
17-Ketosteroids
They comprise a group of steroid compounds which have a
ketone at position 17
19
17-Ketosteroids, Cont’d
• Assay for detection of 17-ketosteroid
compounds
20
17-Ketosteroids, Cont’d
21
THE END
Any questions?
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