bluuebunny/crossref_metadata_2025_split huggingface dataset:
An aberrant nucleus in the telencephalon following administration of ENU during neuroembryogenesis
Authors: Hallas Brian H. , Das Gopal D. 
Published: June 2005

AbstractAdministration of ENU to rats during embryonic development caused the emergence of aberrant nuclei in the dorsal telencephalon. They were located in the corpus callosum, and were composed of pyramidal and stellate neurons. This suggested that the aberrant nuclei arose out of the neurons of cerebral cortex that had failed to migrate during embryogenesis. The aberrant nuclei were found predominantly in the animals receiving ENU on day 18 or earlier of gestation.
A potential mechanism in medroxyprogesterone acetate teratogenesis
Authors: Kimmel G. L. , Hartwell B. S. , Andrew F. D. 
Published: June 2005

AbstractMedroxyprogesterone acetate (MPA) has been shown to be teratogenic in rabbits but not in rats or mice (Andrew and Staples, 1977). Since normal steroid action appears to be mediated, in large part, through interaction with specific steroid receptors, we postulated that the species difference in teratogenicity might be due to a difference in the interaction of MPA with target cells. A primary event in steroid‐cell interaction is the binding of a steroid to intracellular receptors. Studies were initiated to measure the specific nature of MPA binding to glucocorticoid and progestin receptors in appropriate rat and rabbit target tissues. The competition of MPA with 3H‐dexamethasone binding in liver cytosol (glucocorticoid receptor) and with 3H‐progesterone binding in uterine cytosol (progesterone receptor) was determined. In rabbit liver cytosol MPA was as effective at competing for specific dexamethasone binding as the natural glucocorticoids and considerably more effective than the nonspecific steroids. In rat liver cytosol; MPA was only 10% as effective as the natural glucocorticoids, and the competition could not be distinguished from that of nonspecific steroids. A similar species difference was not seen in uterine cytosol MPA competed with progesterone in a similar fashion in both rat and rabbit. These data demonstrate a distinct species difference in the competitive nature of MPA for the glucocorticoid receptor but not for the progestin receptor. The results suggest that MPA, or possibly a metabolite, may be teratogenic in rabbits by binding with specific glucocorticoid receptors to inhibit or alter normal steroidal function in embryo‐fetal development.
Genetic independence of the embryonic reactivity difference to cortisone‐ and 6‐aminonicotinamide‐induced cleft palate in the mouse
Authors: Biddle F. G. , Fraser F. C. 
Published: June 2005

AbstractThe A/J strain of mice is more reactive than C57BL/6J to both cortisone‐ and 6‐aminonicotinamide‐induced cleft palate. A breeding study was set up to determine the genetic control of the differences in embryonic reactivity between the two strains to the two teratogens. In this paper the test for possible association between the two response traits is presented. In the second‐backcross generation of embryos where segregation of the two traits could be studied no association was found. Therefore, any embryonic genes making major contributions to differences in reactivity between the two strains are not the same for the two teratogens.
Influence of drinking water–tap versus purified–on embryo and fetal development in mice
Authors: Staples R. E. , Worthy W. C. , Marks T. A. 
Published: June 2005

AbstractPregnant CD‐1 mice drank either chlorinated tap water obtained at NIEHS from the City of Durham, North Carolina municipal water supply or this same water passed in sequence through an organic removal cartridge and a demineralizer, followed by glass distillation. No significant overall differences in the reproductive status of pregnant mice were noted wnen the two groups were compared. Similarly, no significant overall influence on the incidence of malformed fetuses could be traced to the purity of drinking water. Month by month comparisons indicated that there were three statistically significant differences; all of which indicated improved performance for the mice that drank tap water. When the results for both groups were combined and a month by month comparison was made there was a significant difference in the pregnancy rate for February (68%) as compared with an overall pregnancy rate of 80% and a 79‐93% spread for the other months, but the decrease was due to the low incidence of pregnancy in the group that drank the purified water.
Cytogenetics of extragonadal tumors
Authors: Kaplan Cynthia G. , Askin Frederic B. , Benirschke Kurt 
Published: June 2005

AbstractTissue from six human extragonadal teratomas was obtained for cytogenetic study. These included two gluteal lesions in infant females, and one each of thyroid, mediastinal, sacral and gastric teratomas in males. Tissue culture characteristics indicated tumor growth. All tumors, except the mediastinal lesion showed the presumed karyotype of its host, XX or XY. The mediastinal mass was tetraploid XXYY and contained an X chromatin body and double Y bodies.Our data support the concept that extragonadal teratomas in males and females arise mitotically from diploid cells and are more similar to identical twins. No heterosexual (XX) tumors were seen in males which would be expected in parthenogenetic tumors. The sex chromatin positive tumors seen in earlier studies may have resulted from polvploidy. Thus, male and female extragonadal teratomas have a different origin from the postmeiotic ovarian teratomas.
Influence of various levels of hypervitaminosis A and zinc deficiency on teratogenesis and DNA synthesis in the rat
Authors: Eckhert Curtis D. , Hurley Lucille S. 
Published: June 2005

AbstractAdministration of excess vitamin A during gestation results in gross malformations of the fetus. It has been proposed that the mechanism of action of vitamin A in producing malformations is through a reduction in DNA synthesis and altered cellular differentiation. A similar mechanism has been suggested for the teratogenic effect of zinc deficiency. The simultaneous treatment of pregnant rats with excess vitamin A (3,000 or 30,000 IU/day) and low dietary zinc (0.4 or 9 ppm) resulted in a high incidence of fetal malformations from each treatment with no discernible interaction. Both treatments resulted in brain deformities, but zinc deficiency caused a higher incidence of lung and tail malformations and a general reduction in the uptake of 3H‐thymidine into embryonic DNA. The administration of excess vitamin A resulted in a higher incidence of fetal eye and palate anomalies than did zinc deficiency but had no effect on DNA synthesis. The lack of interaction between the treatments with regard to fetal malformations, the differences in the types of organs which were affected by the two treatments, and the reduction in DNA synthesis by zinc deficiency but not by vitamin A excess suggest that these conditions alter development through different mechanisms.
Teratologic evaluation of synthetic Δ9‐tetrahydrocannabinol in rabbits
Authors: Sofia R. Duane , Strasbaugh Julianna E. , Banerjee Bhola N. 
Published: June 2005

AbstractSynthetic Δ9‐tetrahydrocannabinol (THC) was dissolved in undiluted propylene glycol and administered in daily subcutaneous doses of 15.0, 30.0 or 60.0 mg/kg to pregnant New Zealand white rabbits on days 7–19 of gestation. Maternal food consumption and weight gain were markedly reduced at all dose levels. Embryotoxicity and embryocidal effects were observed in the form of reduced litter weight and number of viable fetuses, respectively, in offspring from pregnant mothers treated with THC. However, on the basis of extensive external, visceral and skeletal examination of all fetuses it may be concluded that THC is not teratogenic in the New Zealand white strain rabbit following subcutaneous administration of doses as high as 60.0 mg/kg/day during the critical period of organogenesis (days 7–19 of gestation). On the other hand, an oral dose of thalidomide (200.0 mg/kg/day), the positive control used in this study, was both embryocidal and teratogenic.
Is there a fetal gasoline syndrome?
Authors: Hunter Alasdair G. W. , Thompson Diane , Evans Jane A. 
Published: June 2005

AbstractTwo children from a small Amerindian community presented with profound retardation, initial hypotonia progressing to hypertonia, scaphocephaly, a prominent occiput, poor postnatal head growth, and additional minor anomalies. Abuse of gasoline by inhalation was a widespread problem in the community, and gasoline inhalation during the pregnancy could be documented in both of the pregnancies. We are raising the question as to whether inhalation of gasoline during pregnancy may be teratogenic in humans.
Interference of lead with implantation in the mouse: A study of the surface ultrastructure of blastocysts and endometrium
Authors: Wide Mariann , Nilsson B. O. 
Published: June 2005

AbstractImplantation chambers, trophoblast and uterine luminal surfaces were examined on days 5 and 6 of pregnancy by electron microscopy in mice with implantation failure due to an intravenous injection of 75 ppm of lead chloride on day 4. Attachment of the trophoblast cells to the surface of the endometrium and closure of the uterine lumina had failed to occur. Uterine epithelial cells in implantation chambers and along the lumina were covered with abundant microvilli. This appearance is similar to that seen in mice in experimental delay of implantation before the oestrogen‐induced attachment of the blastocyst has occurred. It may therefore be assumed that lead has in some way interfered with the activity of ovarian steroid hormones on the endometrium. No significant changes were observed in surface ultrastructure of the blastocysts from the lead‐treated and control groups.
Role of vitamin E in the etiology of spontaneous hemorrhagic necrosis of the central nervous system of fetal hamsters
Authors: Keeler Richard F. , Young Stuart 
Published: June 2005

AbstractThe intraperitoneal inoculation of pregnant hamsters with vitamin E during the first half of gestation reduced the severity or eliminated the occurrence of grossly observable effects of spontaneous hemorrhagic necrosis (SHN) of the central nervous system in their offspring and improved the pre‐weaning viability of their litters. The addition of corn oil (16%) or linoleic acid (8%) to a ration associated with the occurrence of SHN in fetal hamsters enhanced the incidence and severity of the disease, and these effects were moderated by inoculation of the dams with vitamin E.Experimental data indicated that, among multifactorial contributions to the cause of SHN in hamsters, vitamin E availability and levels of dietary polyunsaturated fatty acid played a significant and interrelated role.
Differences in maternal age‐specific rates of down syndrome between Jews of European origin and of north African or Asian origin
Authors: Hook Ernest B. , Harlap Susan 
Published: June 2005

AbstractRates of Down syndrome in livebirths in West Jerusalem in 1964‐1975 were studied in relation to the mother's continent of birth or, if she was born in Israel, to the maternal grandfather's continent of birth. In women of European origin the crude livebirth rate of Down syndrome was 1.3 per 1,000 livebirths. This crude rate and the maternal age‐specific rates in this group were very close to those observed in a Swedish study and two studies of white livebirths in the United States. For West Jerusalem women of North African or Asian origin the crude rate was about 2.4 per 1,000 livebirths, and at all maternal ages except the youngest their rates were higher than for women of European origin. The summary adjusted relative risk for a Down syndrome livebirth for all those of North African or Asian origin, compared to those for women of European origin, was about 1.56. If attention is restricted to mothers born outside of Israel, the adjusted relative risk for mothers born in Europe, the Americas or English speaking countries of the British commonwealth compared to those born in North Africa or Asia was 1.97, consistent with a two‐fold difference in the likelihood of a Down syndrome livebirth between these two groups. To our knowledge this is the first report of ethnic differences in maternal age specific rates of Down syndrome that cannot be plausibly explained by differences in ascertainment.
The interaction of cadmium‐binding proteins (Cd‐bp) and progesterone in cadmium‐induced tissue and embryo toxicity
Authors: Wolkowski‐Tyl Rochelle , Preston Susan F. 
Published: June 2005

AbstractPrevious work indicates that a dimer of Cd‐thionein (Cd‐bp‐D, 19,000 MW) is involved in the hereditary resistance to Cd‐embryotoxicity seen in the inbred NAW/Pr (NAW) mouse strain. Cd‐bp‐D is not detected in virgin females after Cd exposure and is detected only after the first 24 hours of exposure to Cd in an inbred strain (C57BL/10ChPr) susceptible to Cd‐induced em‐bryotoxicity (Wolkowski, 1974; Wolkowski‐Tyl, 1978). Since progesterone (P) is critical for maintenance of pregnancy in mice, we have studied the possible relationship between this hormone and Cd‐bp‐D production. As a model system, we examined effects of Cd treatment on Cd‐bp synthesis in NAW males. It was anticipated that this model could provide information bearing not only on the relationship between P and Cd‐bp‐D production, but also on that between Cd‐bp‐D and Cd toxicity, since a single sc injection of CdCl2 causes typical testicu‐lar hemorrhagic necrosis in NAW males, and these animals make only metallothionein and not Cd‐bp‐D. NAW males were, therefore, given P (0.1 g/Kg bw) and then exposed to Cd. Sephadex gel chromatography (G‐200) of liver cytosol from animals killed 24 hours later detected only Cd‐bp‐D. Testes of these males did not show hemorrhagic necrosis. Since the adrenals of male mammals release P in response to stress, NAW males were stressed by repeated sesame oil or propylene glycol injections (5 ml/Kg bw), or the adrenal was stimulated directly with injections of ACTH (100 IU/Kg bw) for seven days prior to Cd exposure. All methods tested which significantly elevated serum P levels (as confirmed by radioimmunoassay), also resulted in production of Cd‐bp‐D and absence of testicular hemorrhage in Cd‐treated NAW males. Suppression of P release by injection of dexamethazone or corticosterone or by adrenalectomy resulted in testicular hemorrhage and production of only metallothionein after Cd exposure. The relevance of the interaction between P, Cd‐bp‐D and protection against Cd‐induced toxicity seen in the model system was supported by analysis of serum P levels in pregnant females; elevated levels were seen in resistant NAW dams on day 10 of gestation and significantly lower levels seen in dams from a Cd‐sensitive strain.
Teratogenic potential of dichlorvos given by inhalation and gavage to mice and rabbits
Authors: Schwetz B. A. , Ioset H. D. , Leong B. K. J. , Staples R. E. 
Published: June 2005

AbstractDichlorvos (2,2‐dichlorovinyl dimethyl phosphate) is an important organophosphate insecticide and anthelmintic with widespread use. The purpose of this study was to evaluate the teratogenic potential of dichlorvos given orally at the maximum tolerated dose to mice (60 mg/kg/day) and rabbits (5 Mg/kg/day) and by inhalation in both species at a concentration of 4μg/l seven hours daily. Dichlorvos was not found to be teratogenic in either species bv either route of administration.
The survival and implantation of mouse blastocysts at varying degrees of reduced atmospheric pressure
Authors: Blackburn R. O. , Clegg E. J. 
Published: June 2005

AbstractPregnant mice were exposed to reduced atmospheric pressures ranging from 630 to 390 mm Hg during the pre‐implantation and implantation periods and the numbers of embryos surviving 85 hours post coitum compared with those in litter‐mate controls. Even at a pressure of 630 mm Hg (  1,550 mm Hg) there was a significant fall in numbers of normal blastocysts and rise in abnormal forms before implantation, and implantation sites were reduced in number. The numbers of abnormal forms increased and implantation sites decreased at lower pressures, suggesting strongly that the hypoxia of reduced atmospheric pressure was responsible for the abnormalities observed.The pre‐implantation period appears to be one during which the fertilised ovum is at particular risk, both of hypoxic damage and of failure to implant. Implantation may afford a degree of protection against hypoxia.
Teratogenic effects of external egg applications of methyl mercury in the mallard, Anas platyrhynchos
Authors: Hoffman David J. , Moore John M. 
Published: June 2005

AbstractThe embryotoxic potential of external applications of methyl mercury on mallard eggs was investigated to assess the possible impact of mercury transferred from the plumage of effluent‐contaminated aquatic birds to their eggs. Eggs were treated on day 3 of development with microliter applications of methyl mercury that was dissolved with ethyl acetate into an aliphatic hydrocarbon vehicle. Mercury analysis by atomic absorption indicated that almost half of the mercury applied entered the eggs past the shell membranes within several days of treatment. Most mortality occurred within this period at doses of 9 μg of mercury per egg or higher. Decreased embryonic growth resulted with similar doses. A significant incidence of malformations occurred at a dose of 1 μg per egg. These malformations were mainly minor skeletal aberrations and incomplete ossification. With higher doses of mercury, defects included gross external ones such as micromelia, gastroschisis, and eye and brain defects. Application of the aliphatic hydrocarbon vehicle did not result in any of these defects.
Diazepam‐induced cleft palate in the Mouse: The role of endogenous maternal corticosterone
Authors: Barlow S. M. , Knight A. F. , Sullivan F. M. 
Published: June 2005

AbstractThe aims of the experiments were to investigate the effects of diazepam treatment on day 14 of pregnancy in the mouse on endogenous maternal plasma corticosterone levels and induction of cleft palate (CP) in the offspring, and to evaluate any interaction between diazepam and stress‐induced or corticosterone‐induced CP. Sub‐teratogenic doses of diazepam (10 mg/kg orally, given t ice 12h apart) had no significant effect on the induction of CP by 24h maternal food deprivation. Similarly, neither sub‐teratogenic doses (10 or 50 mg/kg, given twice) nor teratogenic doses (100 mg/kg, given twice) of diazepam had any significant effect on the induction of CP by exogenous corticosterone given at low (2.5 mg) or high (10 mg) doses. However, diazepam alone (10‐400 mg/kg) raised endogenous plasma corticosterone levels in a dose‐related way. Mice given teratogenic doses of diazepam, 100 or 200 mg/kg, causing 3‐6% CP, sustained elevated endogenous corticosterone levels for at least 6h after dosing, in comparison with sub‐teratogenic doses of diazepam or vehicle controls. In a comparison of mice given 400 mg/kg diazepam, causing 20% CP, with mice given 2.5 mg corticosterone, causing 25% CP, the mean endogenous corticosterone level was lower in the diazepam group at 1h but higher at 6h after dosing than that of the exogenous corticosterone group. These results suggest that diazepam may cause CP in the mouse by raising endogenous maternal corticosterone levels. The stress of fasting and immobilisation resulting from the heavy sedation caused by teratogenic doses of diazepam may contribute to the elevations in endogenous corticosterone levels.
Interference of lead with implantation in the mouse: Effect of exogenous oestradiol and progesterone
Authors: Wide Mariann 
Published: June 2005

AbstractThe implantation inhibiting effect of an intravenous injection of 75 ppm of lead chloride, giving blood levels of about 32 μmol/l, could be counteracted by exogenous steroid hormones. Subcutaneous injections of 0.1 μg of oestradiol‐17β and 1 mg of progesterone were given together with the lead on day 4 of pregnancy, and the same hormone doses were given also on day 5. The frequency of animals having implantations on day 6 of pregnancy in this group was the same as in the control group (75%), whereas in animals given lead and no hormones, the frequency of pregnancies was only 20%. Morphological examination by light microscopy of implantation sites on day 6 of pregnancy in the lead + hormone‐treated group showed that the decidual swellings contained implanted embryos of a normal appearance. Serum levels of oestradiol‐17β and progesterone in nontreated and lead‐treated mice were not significantly different between the two groups on day 5 of pregnancy. It is suggested that the implantation failure may be due to an effect of lead on uterine responsiveness to ovarian steroids.
Retinoic acid‐induced heart malformations in the hamster
Authors: Taylor I. M. , Wiley M. J. , Agur A. 
Published: June 2005

AbstractIn order to determine the effect of retinoic acid on the developing mammalian heart, pregnant golden Syrian hamsters were given single doses of 80 mg/kg of the teratogen by gavage, at various times in gestation. Examination of the surface features of hearts from near‐term fetuses was followed by microdissection to reveal internal cardiac structures. This has proven to give more reliable results than other methods of determining congenital heart malformation. The results of the study demonstrate that retinoic acid is a potent cardiac teratogen capable of inducing high frequencies of heart abnormalities in a reproducible fashion. The highest rates of malformation resulted from maternal treatment on day 7 (69%), 8 (74%), and 9 (30%) of gestation. Ventriculo‐bulbar malformations including double outlet right ventricle, complete transposition, and an overriding aorta complex were the most commonly seen abnormalities. The findings support the hypothesis that these abnormalities are not entirely discrete entities but are instead part of a single spectrum of malformation.
The formation of caudal hematomas in trypan blue‐treated chick embryos as a function of morphological stage at treatment
Authors: Rajala G. M. , Kaplan S. 
Published: June 2005

AbstractA number of investigations related to trypan blue‐induced hematomas in chick embryos employed variations in the amount of dye injected, route of administration, and length of incubation time before treatment. the present study was done to standardize and further define the teratogenic system to facilitate the design and interpretation of subsequent physiological experiments with trypan blue‐treated embryos.Embryos at Hamburger‐Hamilton stages 11–15 were treated with 20 μl of 1% (w/v) trypan blue solution dissolved in 0.85% NaCl, and were observed at 12 and 24 hours after treatment for evidence of caudal hematomas and death. In this way the population of treated embryos was assessed in terms of malformation and death frequency according to the developmental stage at treatment.The highest incidence of hematomas was found 24 hours after treating embryos at stage 13 (59%), and the highest incidence of death was found 24 hours after treating embryos at stage 11 (75%). These data indicate that stages 13 and 11 exhibit the maximum response to dye treatment in terms of hematoma formation and death. No significant differences (P >0.05) were found between stages 13 and 14 for hematoma or death frequency at 12 or 24 hours after treatment. We suggest that the optimum procedure for subsequent experiments with this teratogenic system would consist of choosing stage 13 and 14 embryos for trypan blue treatment.