摘要:

AbstractThe acardiac monster represents one of the most severe but rare congenital anomalies. It occurs only in multiple gestations associated with vascular anastomoses between the affected fetus and its co‐twin. The prenatal diagnosis of an acardiac fetus must be suspected in any multiple gestation in which cardiac activity cannot be documented sonographically in a growing fetus. We report an acardiac fetus occurring in a spontaneously conceived triplet pregnancy. A review of the literature, including pathogenetic theories and sonographic reports, is discusse

ISSN:0040-3709    

DOI:10.1002/tera.1420370102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractTo examine the effects of vitamin A administered during the preimplantation period, pregnant C3H mice were exposed to teratogenic doses of the vitamin 60 h after copulation. Fetuses were examined for gross abnormalities on the 18th day of gestation and viability, cell number, mitotic index, and chromosome structure were assessed in 81‐h blastocysts to determine whether embryotoxic effects were apparent in the preimplantation embryo. There was a reduction in the fetal weight of 18‐day fetuses treated in this manner with 15,000 and 30,000 IU vitamin A (p<0.0003 in each case), and doses of 10,000 IU and greater were associated with a significantly higher incidence of gross abnormalities. Malformations included exophthalmos, anophthalmia, microphthalmia, exencephaly, exomphalos, and limb defects. Administration of 30,000 IU vitamin A resulted in resorption and intrauterine death in 70% of cases. There was no indication that vitamin A adversely affected 81‐h blastocyst viability, cell number, mitotic index, and chromosome structure. The findings suggest that the teratogenic effects that were noted later in fetal life were the result of an action on the developing fetus of the vitamin at a stage later than 81‐h and are consistent with the relative resistance of the preimplantation embryo to toxic injury. Persistence of vitamin A, either in the mother or the embryo, is the most likely explanation for the later expression of toxic injury, which is characteristic of the effects that are noted as a result of exposure to the teratogen during the period of organo

ISSN:0040-3709    

DOI:10.1002/tera.1420370103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractZinc, at a concentration of 5 or 10 μg/ml medium, has been shown to protect mouse preembryos in vitro from the toxicity of cadmium at a concentration of 5 μg/ml medium after a simultaneous treatment of the ions from four‐cell to morula or from morula to blastocyst for 24 hours. Such an amelioration indicates that cadmium toxicity is a result of the unique property of the cadmium ion and is not due to an alteration in the culture medium after the addition of an extra metallic ion. Zinc probably ameliorates cadmium treated mouse preembryo by competing with cadmium for uptake or some other metabolic processes. In view of the well‐documented competition between cadmium and zinc ions for binding sites in many other cell types, some macromolecules to which similar divalent metallic ions bind competitively may also exist in the mouse preembryo. This suggests that a protective mechanism dependent on the metal‐metal interactions begins to operate in the mouse preembryo at a very early stage of differentiation before impla

ISSN:0040-3709    

DOI:10.1002/tera.1420370104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA marked increase or “epidemic” in ventricular septal defects (VSD) in recent years has been reported by the Center for Disease Control. Many pediatric cardiologists believe that this increase is simply a reflection of more intensive diagnosis and evaluation of infants throughout the country. Yet to our knowledge there has been no objective evidence for this explanation. We evaluated this possibility by considering records on live births occurring in 1970–1983 in the counties surrounding Albany, New York. In that period a single group of pediatric cardiologists has been evaluating all infants with suspected or confirmed cardiac defects in this area. We limited this analysis to ventricular septal defects unassociated with any cardiac syndrome complex. Thus, VSDs occurring as part of cyanotic heart disease or other complex cardiac “syndromes” were excluded. Consistent with the reported national trend, the estimated prevalence rate of ventricular septal defects diagnosed under 1 year of age in this period has increased from 1.0 per 1,000 live births in 1970 to 4.0 per 1,000 in 1983. Several factors indicate that this rise resulted from more intensive diagnoses at earlier ages in this period: (1) for all patients with VSD, the median age at diagnosis fell from 251 days in 1970 to 25 days in 1983; (2) the most severe VSDs (based on an index derived from pathophysiologic data) were constant from 1972 afterward at an estimated rate of about one per 1,000 (although the estimated rates were lower than this in 1970 and 1971) while the milder defects rose from an estimated rate under 0.5 per 1,000 to over 3.0 per 1,000 in this interval; (3) changes in diagnostic criteria for VSD occurred, so that a murmur thought to be innocent in 1970 might, if heard later in the interval, lead to a diagnosis of VSD; (4) echocardiography began in the latter part of the interval, and the sharpest increase in the estimated rate of VSD occurred after its introduction in 1977 in our area; (5) the prevalence of complex VSD remained relatively stable throughout the period, being 0.4 per 1,000 live births in the first 3 years of the study and 0.5 per 1,000 in the last 3 years; (6) there was an increase in diagnoses of spontaneous closure of VSDs from 7% in 1970 to 32% in 1983. All of these factors are consistent with the view that the increase of VSD resulted from changes in ascertainment due to changes in methods and criteria for diagnosis of th

ISSN:0040-3709    

DOI:10.1002/tera.1420370105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractAdministration of a single dose of cyclophosphamide (20 mg/kg) to Charles Foster (CF) rats on day 12 of gestation (i.e., well after neural tube closure) results in exencephaly in almost 100% of living fetuses at term (Padmanabhan, '84). Following the same treatment, embryos/fetuses were collected at various intervals of time (from 8 hr to day 19 of gestation) and studied histologically. At 10 hr after treatment, the neuroepithelium (NE) of the brain vesicles and the neural crest‐derived ganglia exhibited pronounced cell death. By day 13, cell death appeared to be more intense and extensive in the NE; the mesenchyme (ME) was less proliferative and was loosely organized. In the following days, the NE presented vacuolizations which coalesced into cavities; these cavities were often bilaterally symmetrical, contained free neuroblasts and erythrocytes, and subsequently opened into the ventricles. The choroid plexus hypertrophied, the ventricles distended, and the NE gradually became very thin. The hypertrophied capillaries of the ME cleaved through the NE, thus delaminating an outer stratum. Subcutaneous blebs developed over the brain vesicles and communicated with the cavities in the brain. Thus the ventricles and the blebs came into direct communication. The ME dorsal and lateral to the brain was loose, and at no site was it organized into the skull primordium. By day 19, there were clear and multiple discontinuities in the walls of the brain. Initial cell death and vacuolization in the NE, inhibition of ME proliferation followed by hypertrophy of the choroid plexus, and possibly enhanced intraventricular pressure and hemorrhage and edema of the ME seem to underlie this process of reopening of the closed neural tub

ISSN:0040-3709    

DOI:10.1002/tera.1420370106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractPregnant LM/Bc female mice were given a 10‐minute hyperthermic exposure in a 43°C waterbath during the period of neural tube closure. On day 15.5 of gestation, the females were killed, and the fetuses were examined for exencephaly. Following a single treatment on day 8.0, 8.5, 8.75, or 9.0 of gestation 1.7, 13.6, 2.9, and 0.8% of the respective fetuses displayed exencephaly. With two treatments, one on each of gestational days 8.5 and 8.75, or three treatments, one on each of gestational days 8.5, 8.75, and 9.0, the percentage of exencephalic fetuses increased to 28.3 and 59.3%, respectively. The increased response to multiple treatments was not due to an increase in the number of susceptible embryos but rather was due to the increased number of treatments. The results of this study suggest that with increasing numbers of treatments, the embryo's ability to recover from the hyperthermic exposure is lessened, resulting in an increase in exencepha

ISSN:0040-3709    

DOI:10.1002/tera.1420370107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractFemale rats of WM (Wistar‐Mishima)/Nem strain were mated with WM/Nem (group W) or BDIX/Nem males (group WB), and BDIX/Nem females were mated with BDIX/Nem (group B) or WM/Nem males (group BW). On day 8 of gestation, pregnant females were treated intraperitoneally with 1% aqueous solution of trypan blue at a dose of between 20 and 120 mg/kg of body weight. On day 20 of gestation, fetuses were examined for external, visceral, and skeletal malformations.In group W, fetal mortality increased dose dependently at doses higher than 20 mg/kg, and incidences of external, visceral, and skeletal malformations were significantly higher than control at doses of 30 mg/kg and more. In group B, fetal mortality and the incidence of external malformations were significantly higher than control only in the group treated with 120 mg/kg, and no significant increase of visceral and skeletal malformations was shown. It was confirmed that BDIX strain is much more resistant to trypan blue teratogenicity than WM strain.In group BW, nearly the same teratogenic effects were shown as in group W in terms of fetal mortality and incidence of malformations. However, in group WB, teratogenic effects were not so remarkable as in group BW, suggesting patroclinous effects in teratogenic susceptibility to trypan blue. In group BW, sex differences in teratogenic susceptibility were found; male fetuses were more susceptible to trypan blue than female

ISSN:0040-3709    

DOI:10.1002/tera.1420370108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe effects of 40, 50, and 60 mg/kg streptozotocin (SZ) on the body weights and the glucose concentration and the osmolarity of the serum of adult rats were determined. Serum prepared from these SZ‐dosed rats was used in embryo culture experiments to investigate effects of diabetic serum on rat embryos during organogenesis. The diabetic serum resulting from each of the tested doses of SZ was teratogenic to 9.5‐day rat explants (embryos and their membranes), causing a range of dysmorphic lesions including cranofacial defects, heart defects, and abnormalities of the branchial arches and the otic capsules.Explants cultured in serum prepared from rats dosed with 60 mg/kg SZ also showed abnormal morphology of both the visceral yolk sac and the embryonic blood cells in the yolk sac capillaries.The development of explants repeatedly transferred between control and diabetic serum indicated that the severity of the dysmorphic effect was dependent on the duration of exposure to diabetic serum. The alternation of sera did not in itself appear to be damaging to the embryos.Explants cultured in control serum, control serum with its glucose concentration increased to that of the diabetic serum, or diabetic serum all took up the same amount of glucose from their culture medium; 30% of the embryos from the diabetic serum were abnormal compared to only 4% from the control serum and the control serum plus gluc

ISSN:0040-3709    

DOI:10.1002/tera.1420370109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractWhen female mice of the Jcl:ICR strain were mated with a male either (1) continuously throughout the day or (2) overnight or (3) during 2 hours in the morning at light period, the interlitter variability of fetal body weight on the 18th day of gestation was smallest in the group with short‐period mating. Thus, in the embryonic stage‐specific teratological experiments, this mating schedule is advised. Even for routine reproductive toxicity testing protocols, the short‐period mating may be preferable for the purpose of increasing test sensit

ISSN:0040-3709    

DOI:10.1002/tera.1420370110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractAlthough many pregnant women undergo anesthesia and many others are occupationally exposed to anesthetics every year, assessment of the teratogenic risk of anesthetic agents in humans must currently be made on the basis of very limited data. Available studies suggest that administration of an anesthetic to a pregnant woman will usually not have a deleterious effect on embryonic or fetal development. The risk of congenital anomalies does not appear to be substantially increased among children of women who have chronic occupational exposure to anesthetic gases during pregnancy, either, but miscarriages may occur more frequently than expected among such women. There is an urgent need for publication of good human epidemiologic and experimental animal studies on the teratogenicity of anesthetics.

ISSN:0040-3709    

DOI:10.1002/tera.1420370111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY