Fetal folds

With both techniques, the heads of one-half of the fetuses can be fixed in Bourn s fixative for subsequent freehand sectioning and examination. A common artifact induced by fixation in rabbit fetal heads is retinal folding. 

Hamster (Golden Syrian) 10 d Gd 5-14 (GO) 1.5 (irregular supraoccipitals, visceral abnormalities 2-fold increase in fetal mortality 30% decrease in fetal weight) Chernoff et al. 1979a Endrin... 

In rats, the ability of the liver to sulfonate phenol develops with age. Analysis of 105,000 g hepatic supernatants indicated that fetal rats show very low activity (about 3% of the average of 7-week old male and female values which show a male to female ratio of almost 2). By post-natal day 2, the activity increases more than 10-fold in both sexes, a level that is maintained through day 24 (Iwasaki et al. 1993). 

ACh receptors are present in the post-junctional membrane of the endplate, in the junctional folds. The nicotinic ACh receptor at the motor endplate has five subunits, two os, (3, 5 and . In addition, a Y subunit instead of an e subunit may be present in the so-called extra-junctional or the fetal receptor. The five subunits are arranged as a cylinder around a central funnel-shaped pore, the ion channel. The two a subunits each carry a recognition site which binds nicotinic agonists such as ACh and antagonists such as the neuromuscular blocking agents. Whilst ACh must bind to both subunits to produce an effect, it is sufficient for... 

The observed growth deficiencies are associated with an inability of the baby to catch up due to a slower than normal rate of development. Other infrequent outcomes include skeletal malformations such as deformed ribs and sternum, scoliosis, malformed digits, and microcephaly. Distinctive facial anomalies have been associated with a diagnosis of fetal alcohol syndrome small eye openings, epicanthal folds, failure of eyes to move in the same direction, short upturned nose, flat or absent groove between nose and upper lip, and thin upper lip. Visceral deformities may also be present heart defects, genital malformations, kidney, and urinary defects. 

Muscle-derived differentiation factor (MDF) induces tyrosine hydroxylase expression in a variety of central nervous system neurons, including those of striatum, cerebellum, and cortex. Normally, i.e., without MDF, these neurons do not express this enzyme of catecholamine synthesis. Further in vitro studies revealed that MDF enhances TH-mRNA 40-fold in fetal mesencephalic neurons. In vivo studies, employing infusion of partially isolated MDF, reported this molecule to enhance tyrosine hydroxylase activity in dopamine-depleted striata of 6-OHDA-lesioned animals. Furthermore, an increase of striatal dopamine concentrations and a partial compensation of rotational asymmetry were observed. In contrast, dopaminergic parameters were not affected by administration of MDF in control animals, suggesting that adult dopaminergic neurons may regain sensitivity toward differentiation factors after lesion. 

A combination of 150 mg/kg caffeine administered by injection to pregnant rats in conjunction with a single dose of 9,756 mg/kg DEHP on day 12 of gestation caused a 5-fold increase in the number of dead and resorbed fetuses and nearly a 4-fold increase in the malformed survivors as compared to the effects of DEHP alone (Ritter et al. 1987). The mean fetal weight was also depressed. The addition of the caffeine to the treatment using equimolar quantities of 2-ethylhexanol and 2-ethylhexanoic acid at doses half of the molar quantity used for DEHP resulted in 2-30-fold increases in the dead and malformed fetuses and malformed survivors, but only minor decreases in the fetal weights. 

A 4.5 ml aliquot of each concentration of the test substance was dispensed into separate tubes and each was mixed with a 0.5 ml aliquot of the stock virus suspension. The mixtures were vortex mixed for a minimum of 10 seconds and held for the remainder of the specified exposure times at the appropriate temperature. Immediately following each exposure period, a 0.1 m aliquot was removed from each tube and the mixtures were titered by 10-fold serial dilutions (0.1 ml+0.9 ml test medium) and assayed for the presence of virus. Note to decrease the product cytotoxicity, the first dilution may be made in fetal bovine serum or other appropriate neutralizer with the remaining dilutions in test medium. 

The rat is placed in a dorsal position on an undersheet and the fur is moistened with ethanol/water. The abdominal cavity is opened and the abdominal wall folded back. The uterus is exposed and the amniotic fluid is withdrawn by puncturing the amniotic sac with a syringe. The uterus is then placed on a plastic film and opened. The placentas with the fetuses are detached from the uterus. The placentas are then detached from the fetuses. After removing the fetal membranes the fetuses are removed and immediately killed under CO2 atmosphere. The amniotic fluid is aspirated with a disposable syringe. 

In genetically altered mdrlajb (—j—) knockout mice without P-gp/ both transplacental transport of P-gp substrates and the incidence of fetal malformations increase (93). Transplacental transport of the P-gp substrates/ digoxhi/ saquinavir and paclitaxel/ was increased 2.4-/ 7-, and 16-fold/ respectively/ in the knockout mice compared to transport in the wild-type animals. In another murine study/ mdrlajh (—j—) fetuses were susceptible to cleft palate malformation induced by prenatal exposure to a photoisomer of avermectin Bla/ whereas their wild-type litter mates were protected from the teratogen (87). 

In the 1994 APT overview fetal extracranial bleeding was rare, and there was no clear excess with prolonged antiplatelet therapy. Most major extracranial bleeds are gastrointestinal, and a meta-analysis of the placebo-controlled trials demonstrated that prolonged aspirin treatment increased the risk of gastrointestinal bleeding by around 1.5 to 2-fold (70). However, unlike serious vascular events, such bleeds rarely result in permanent disability or death. 

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