Experimental study of umbilical cord length as a marker of fetal alcohol syndrome.

Umbilical cord length has long been investigated as a potential marker of intrauterine events that may place the neonate at risk for future adverse developmental sequelae. Experimentally, significantly shortened cords have been reported in association with prenatal exposure to common drugs of abuse. This study in rats reports the time course of effects on umbilical cord length of a daily maternal ethanol gavage (3,200 mg/kg) from gestational day 6 through termination of pregnancy at either day 17, 18, 19, or 20. A total of 786 fetuses derived from 60 litters were examined. Control fetuses demonstrated a linear increase in umbilical cord length and body weight gain during late gestation, findings that support previous studies. The body weights of the ethanol-exposed fetuses were reduced significantly on all gestational days examined, indicating intrauterine growth retardation, a characteristic of fetal alcohol syndrome. Similarly, acute fetal akinesia as well as long-term sequelae stemming from impaired neurological development would result from the elevated blood ethanol levels achieved in this study. The umbilical cords of ethanol-exposed fetuses were significantly shorter on gestational days 19 and 20 in comparison to their controls, while cord lengths on days 17 and 18 were not shortened significantly. A stretch hypothesis has been proposed suggesting that the degree of fetal activity is the main determinant of umbilical cord length. In rats, there is a physiologic diminution of the volume of amniotic fluid (oligohydramnios) in late gestation (day 19 to term), which restricts fetal movements but does not appear to alter the linear relationships between gestational age and cord length in controls, thus arguing against the stretch hypothesis. However, cord lengths in the ethanol-exposed fetuses plateaued in late gestation, suggesting possible adherence to a stretch hypothesis. This dichotomy is discussed emphasizing fetal growth and activity as well as intrauterine space.

Unilateral suprainguinal ectopic scrotum: the role of the gubernaculum in the formation of an ectopic scrotum.

A rare case of ectopic scrotum is described together with a review of the literature and a discussion of the embryological role of the gubernaculum in the formation and location of normal and ectopic scrota. We identified 16 reported cases of a suprainguinal ectopic scrotum, 4 cases of a femoral ectopic scrotum, 26 cases of penoscrotal transposition, and 19 cases of a perineal (accessory) scrotum. Although the gubernaculum is a prerequisite for the ultimate location of both the testis and scrotum, its role is complicated by the subsequent differential growth of the labioscrotal folds in which the gubernaculum is stabilized. If this interaction is disturbed, the result may be a suprainguinal ectopia, penoscrotal transposition or a perineal scrotum. A femoral ectopic scrotum, unlike the above, is the result of an aberrant gubernacular stabilization. While the etiology of these malformations is likely to be multifactorial, the existence of an inbred strain of rats characterized by a high incidence of an ectopic scrotum suggests a genetic component to this anomaly.

The incidence of renal anomalies at full term in fetal rats is synergistically increased by estradiol (but not testosterone) supplementation on day 18 of alcoholic gestation.

BACKGROUND/PURPOSE: Fetal alcohol syndrome is characterized by facial dysmorphology, mental and growth retardation, and somatic anomalies including hydronephrosis. The authors sought to determine the influence of exogenous testosterone or estradiol on the incidence of hydronephrosis in a rodent model of fetal alcohol syndrome (FAS). METHODS: Pregnant rats were fed a liquid diet containing 35% ethanol-derived calories from gestation day 6 through 15, with exogenous testosterone or estradiol supplementation on day 18. On day 20, fetal kidneys were examined for evidence of hydronephrosis, and fetal serum estradiol concentrations were determined by radioimmunoassay. RESULTS: Maternal estrogen supplementation resulted in very high fetal serum estradiol levels that were not additionally increased by alcoholism. Despite this fact, the expression of renal malformations was highest in the alcoholic, estradiol-supplemented offspring. Additionally, the rate of renal malformations was significantly higher in the estrogen-supplemented alcoholic group than in the strictly estradiol animals, yet the fetal serum estradiol concentrations did not differ between the two groups. CONCLUSIONS: This suggests that ethanol may act synergistically with estradiol to increase the rate of renal anomalies including hydronephrosis. Such damage may persist via a suppression of normal testosterone-stimulated renal growth and development. FAS includes significant renal anomalies characterized by hydronephrosis in both animal models and affected children. Although the long-term functional sequelae of hydronephrosis and reflux are well known, the progression of renal disease in FAS children remains to be documented.

C-type virus particles in placentas of rhesus monkeys after maternal treatment with recombinant leukocyte A interferon.

Interferon inhibits the normal replication of C-type virus particles grown in vitro. The ability of interferon to produce a similar effect in vivo was tested in rhesus monkey placentas which are known to contain C-type virus particles. Samples of placenta from 6 monkeys treated with recombinant leukocyte A interferon (25 x 10(6) units/kg) for 7 to 21 days and from 6 control monkeys were examined in the electron microscope. Budding and immature C-type virus particles were present in every placenta examined from both interferon-treated and control monkeys. Mature particles were found in placentas from 3 of 6 monkeys in both treated and control groups. Possible explanations for the absence of detectable effects of interferon in C-type virus particle formation in these placentas are unresponsiveness of the trophoblast to interferon or inadequate exposure time to interferon of placental sites from which C-type particles are produced.

Tubuloreticular inclusions in placental chorionic villi of rhesus monkeys after maternal treatment with interferon.

Tubuloreticular inclusions were observed in placental chorionic villi of rhesus monkeys after pregnant female monkeys were injected intramuscularly with recombinant leukocyte A interferon (25 X 10(6) units/kg). They were identified in endothelial cells, fibroblasts, and Hofbauer cells of the chorionic villi, providing evidence that interferon crossed at least part of the maternal-fetal partition. Induction of tubuloreticular inclusions in these cells by exogenous interferon has not been previously reported. Tightly packed regular tubular arrangements appeared in endothelial and Hofbauer cells and loosely organized tubular arrays in fibroblasts. The maximum dimension of the tubuloreticular inclusions measured 3 micron and the diameter of the tubules was 20 nm. The tubuloreticular inclusions were continuous with, and surrounded by, smooth endoplasmic reticulum that was often connected to rough endoplasmic reticulum. The tubuloreticular inclusions were not detected in placental chorionic villi from monkeys not treated with interferon or from interferon-treated monkeys 30 days after cessation of treatment. These results indicate that the formation of tubuloreticular inclusions in rhesus monkey placentas was a transient response associated with elevated serum levels of interferon.

Effects of the environment upon fetal development: concepts and design.

A brief description is presented on the known causes of development defects in humans. The definition of "teratogen" is expanded to include other aspects of developmental toxicity and the techniques used to assess environmental effects are discussed. A method for assessing human risk with a potential developmental toxin is presented and some of the frustrations confronting developmental toxicologists are outlined.

Retinoic acid embryopathy.

Retinoic acid, an analogue of vitamin A, is known to be teratogenic in laboratory animals and has recently been implicated in a few clinical case reports. To study the human teratogenicity of this agent, we investigated 154 human pregnancies with fetal exposure to isotretinoin, a retinoid prescribed for severe recalcitrant cystic acne. The outcomes were 95 elective abortions, 26 infants without major malformations, 12 spontaneous abortions, and 21 malformed infants. A subset of 36 of the 154 pregnancies was observed prospectively. The outcomes in this cohort were 8 spontaneous abortions, 23 normal infants, and 5 malformed infants. Exposure to isotretinoin was associated with an unusually high relative risk for a group of selected major malformations (relative risk = 25.6; 95 per cent confidence interval, 11.4 to 57.5). Among the 21 malformed infants we found a characteristic pattern of malformation involving craniofacial, cardiac, thymic, and central nervous system structures. The malformations included microtia/anotia (15 infants), micrognathia (6), cleft palate (3), conotruncal heart defects and aortic-arch abnormalities (8), thymic defects (7), retinal or optic-nerve abnormalities (4), and central nervous system malformations (18). The pattern of malformation closely resembled that produced in animal studies of retinoid teratogenesis. It is possible that a major mechanism of isotretinoin teratogenesis is a deleterious effect on cephalic neural-crest cell activity that results in the observed craniofacial, cardiac, and thymic malformations.

Adrenalectomy in the ferret.

A simple adrenalectomy technique is presented for the ferret (Mustela putorius furo). The adrenal glands were removed in two operations with an interim recovery period of approximately 1 week. The right adrenal should be removed first, as the surgery is complicated on that side by fascia which binds the adrenal to the inferior vena cava. Salt solution (1% NaCl) in place of water will maintain sodium balance.

Embryology of the eye.

A brief description of the basic patterns of mammalian development of the eye is presented based on events as they occur in human beings. The emphasis is not on the details of this development, but rather on its organization and timing, with a figure of comparative development providing a comparison of similar events in man, rat, mouse, and chick.

Interlaboratory comparison of behavioral testing.

New requirements by several regulatory agencies for testing the psychotoxic potential of new drugs, chemicals, and environmental contaminants raise unique problems. In order to assess intra- and interlaboratory reliability of behavioral tests a model animal maze learning procedure was designed and run in 3 cooperating laboratories. Uniform procedures were written and identical mazes were constructed. Normal control animals of identical age and sex, but of different strains, were used by the participants. A positive control group of neurologically impaired rats was run by one laboratory. Significant differences in test results among the laboratories were found. Data obtained from the positive control animals (mean errors=28.3) indicated a learning impairment statistically significant compared to the negative control data (mean errors=12.7) from any of the participating laboratories. Based on the results of this study, a reasonable standard of interlaboratory reliability in behavioral testing appears an attainable goal.

Comparative female reproductive tract development and morphology.

A brief description of the basic pattern of mammalian organogenesis of the female reproductive tract is presented based on events as they occur in human beings. The emphasis is not on the details of this development, but rather its organization and timing. Tables of comparative development provide a comparison of similar events between man, rat, mouse, and chick.

Potentiation of methotrexate embryolethality by aspirin in rats.

The augmentation of methotrexate-induced embryotoxicity by aspirin was studied. Pregnant Charles River CD rats were given methotrexate or aspirin alone or in combination on gestation day 9 or 12. The frequency of fetal abnormalities was not affected and fetal body weight loss was not additive in the combined treatment. However, pretreatment with aspirin (200 mg/kg) significantly enhanced the embryolethality of methotrexate given at soes of 0.2 mg/kg on day 9 and 1.5 mg/kg on day 12. Studies with tritiated methotrexate in pregnant rats demonstrated that aspirin delayed the renal excretion of methotrexate and increased the concentrations of methotrexate in maternal plasma and the embryos. It is suggested that these effects are responsible for the observed potentiation of embryolethality.

Comparative developmental aspects of selected organ systems. II. Gastrointestinal and urogenital systems.

A brief description of the basic patterns of mammalian organogenesis of the gastrointestinal and urogenital systems is presented based on events as they occur in human beings. The emphasis is not on the details of this development, but rather on its organization and timing, with tables of comparative development providing a comparison of similar events in man, rat, mouse, and chick.