摘要:

AbstractMescaline was administered orally at doses of 16 and 32 mg/kg on the seventh through tenth days of gestation to pregnant cream‐strain hamsters. This treatment resulted in a dose‐dependent effect on reproductive success and skeletal ossification. The effect of mescaline on reproductive success included an increased number of resorptions resulting in a decreased litter size. The 32 mg/kg dose of mescaline caused 48.8% resorptions, while 16 mg/kg and control animals had 12.0% and 6.4% resorptions, respectively. Litter size was decreased from 12.0 pups in controls to 10.3 (16 mg/kg) and 6.5 (32 mg/kg) pups per litter in treated groups. No gross abnormalities were observed at necropsy; there was, however, a dose‐dependent increased delay in the ossification of the skull, sternum, and metatarsals. Both epinephrine and norepinephrine caused a decrease in reproductive success when administered at 500 μg/kg. Epinephrine appeared to cause a trend towards preimplantation wastage as indicated by an increased corpora lutea to implantation site ratio (from 1.3–1.9). Norepinephrine, however, caused an increased number of resorptions (29.1% in controls). Both norepinephrine and epinephrine produced similar delays in ossi

ISSN:0040-3709    

DOI:10.1002/tera.1420230302

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

年代:1981

数据来源: WILEY

摘要:

AbstractAn 11‐week human fetus with megacystis, prostatic dysgenesis, and lateral displacement of the abdominal muscles is described. We suggest that a subtle outflow obstruction of the very early bladder may give rise to both bladder dilation and bladder wall dysgenesis. The bladder dilation may produce abdominal muscle dysplasia or atrophy and almost certainly produces dilation of the prostatic urethra. The dilation of the prostatic urethra disrupts the formation of the prostat

ISSN:0040-3709    

DOI:10.1002/tera.1420230303

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

年代:1981

数据来源: WILEY

摘要:

AbstractAt least 19 human anencephalic specimens have been published which have the facial features of holoprosencephaly. All categories of holoprosencephaly are represented except ethmocephaly, the rarest form. Because of current scientific and clinical interest in both neural tube defects and holoprosencephaly it seems important to establish whether or not this association occurs by chance alone. The study of human embryos with holoprosencephaly by Matsunaga and Shiota ('78) and the anencephalic collection of Lemire et al ('78) suggests the association may be real.

ISSN:0040-3709    

DOI:10.1002/tera.1420230304

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe craniofacial anatomy of two anencephalic human specimens with the facial features of holoprosencephaly is reported. Many of the malformations have distinctly holoprosencephalic or anencephalic features. Absence of the entire ethmoid complex, observed in both specimens of the present study, has rarely been described and, to our knowledge, has never been confirmed histologically. The significance of agenesis of the ethmoid bone in the development of normal and holoprosencephalic facial features has not been considered previously. On the basis of several morphological variations in the two specimens described, it is evident that the ethmoid bone provides integral support in multiple planes for tissues of the median face. It is postulated that the spatial relationships of the bony and soft tissue components of the median face are guided and maintained by the ethmoid complex during morphogenesis. Specifically, hypotelorism and superiorly displaced structures of the nose and upper lip may well represent migration of embryonic tissues into areas normally occupied by the ethmoid bone. Absence of the sella turcica and pituitary gland is ascribed to the holoprosencephalic process. A variant of choanal atresia, due to collapse of the pterygoid plates, is described.

ISSN:0040-3709    

DOI:10.1002/tera.1420230305

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

年代:1981

数据来源: WILEY

摘要:

AbstractIntraperitoneal injection of acrylonitrile at 1.51–2.26 mmole/kg (80–120 mg/kg) or propionitrile at 0.54–1.51 mmole/kg (30–83 mg/kg) on the morning of Day 8 of gestation in the hamster induced exencephaly, encephalocoeles, and rib fusions and bifurcations in the offspring. These doses of the aliphatic nitriles also resulted in obvious toxicity to the dams. Multiple intraperitoneal injections of sodium thiosulfate at 4.03 mmole/kg (1 gm/kg) protected both dams and embryos against toxicity. When the larger doses of either acrylonitrile or propionitrile were given in the presence of sodium thiosulfate, teratogenic effects were observed in the absence of overt signs of maternal poisoning. A survey of the literature describes many studies which demonstrate that acrylonitrile and propionitrile are converted in vivo to toxicologically significant concentrations of cyanide and that sodium thiosulfate, an established cyanide antagonist, can provide protective actions against poisoning by either acrylonitrile or propionitrile. The observations suggest that the teratogenic effects of both acrylonitrile and propionitrile are related to the metabolic release of

ISSN:0040-3709    

DOI:10.1002/tera.1420230306

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe previous study (Willhite et al., '81) linked the administration of acrylonitrile or propionitrile in the pregnant hamster to the production of severe axial skeletal (dysraphic) malformations in the hamster fetus. The present investigation dealt with histological study of both early embryos and term fetuses challenged with a teratogenic dose of either of these nitriles. Inspection of hamster embryos 10 hours after the teratogenic stimulus revealed mesodermal changes including a reduced number of cells, shrinkage of the cell cytoplasm, and enlarged extracellular spaces. In addition, a reduced number of mitotic figures and focal necrobiosis were noted. The affected embryos were smaller and were delayed in their development as compared to controls. Analysis of the fourteen‐day‐old hamster fetuses revealed the basichondrocranium in both cranioschisis occulta with encephalocoele and cranioschisis aperta with exencephyaly to be shorter than control and lordotic to the vertebral axis. These alterations were more accentuated in cranioschisis aperta than in cranioschisis occulta. The ultimate skeletal malformations may be the reflection of a primary paraxial mesodermal insufficie

ISSN:0040-3709    

DOI:10.1002/tera.1420230307

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

年代:1981

数据来源: WILEY

摘要:

AbstractEleven urea compounds were administered individually as a single oral dose to rats either on day 12 or 14 and to mice on day 10 of pregnancy. 1‐Methylurea and 1‐ethylurea were not teratogenic in either of the animal species. Administration of 1‐methylthiourea and 1‐ethylthiourea, however, resulted in high incidences of malformations in the rat but not in the mouse fetuses. The types of malformation were similar to those produced by the known teratogen ethylenethiourea. Methylated ureas such as 1,3‐dimethylurea, 1,3‐dimethylthiourea, 1,1,3,3‐tetramethylurea, and 1,1,3,3‐tetramethylthiourea were fetotoxic and produced malformations in the tail, palate, or extremities of the surviving rat and/or mouse fetuses. These findings suggest that the teratogenic properties ofN‐alkylureas can be categorized into two groups, i.e., mono‐alkylated thioureas and methylated

ISSN:0040-3709    

DOI:10.1002/tera.1420230308

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe effects of diazepam on the development of explanted stage 4 chick embryos were investigated. Diazepam, at 10–120 μg/ml, preferentially inhibited closure of the neural tube. This effect was reversible. Concentrations of 150–200 μg/ml inhibited not only neural tube closure but also blastodermal expansion, somite formation, and heart development in 52% of the embryos. Concentrations above 200 μg/ml were highly embryotoxic. Electron microscopy of affected neuroepithelial cells revealed that (1) apical surfaces were much smoother than usual and (2) apical filament bundles, which are generally thought to provide motive forces for uplifting of neural folds, were not well organized and often lacked alternating dark and light areas along their length. These findings and the fact that changes in cell surface topography reflect the contractile activities of underlying filament bundles suggest that the observed “smoothing” effect on apical cell surfaces and neural tube closure defects are due, at least in part, to the impaired ability of these filament bundles t

ISSN:0040-3709    

DOI:10.1002/tera.1420230309

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

年代:1981

数据来源: WILEY

摘要:

AbstractGross malformations of the external, middle, and internal ear were seen in fetal monkeys following maternal ingestion of thalidomide. Twenty‐five pregnant bonnet monkeys (Macaca radiata) were each given a single oral dose of 10 mg/kg of thalidomide on day 24, 25, 26, 27, 28, or 29, or 30 mg/kg on day 25 or 28 of gestation. (Day of mating is assumed to be day zero of pregnancy.) The skeletons, processed and stained with Alizarin Red S, were examined for changes in configuration and/or ossification of the ossicles and temporal bones. Bilateral temporal bones of one case, treated on day 24, were sectioned at 10 μm and examined histologically. Twelve fetuses collected at 70 ± 3 days of gestation showed no gross ear defects, while 10 out of 13 fetuses collected at 100 ± 3 days of gestation had structural anomalies similar to those observed in humans. All malformations were severe in fetuses treated on day 24 of gestation and lessened in degree of severity with treatments on days 25–28. Fetuses treated on day 29 were normal. External ear anomalies included microtia with meatal atresia or stenosis, and varying degrees of auricular hypoplasia. Defects of the middle ear were predominantly hypoplasia of malleus, incus, and tympanic ring. Fused ossicles and cochlear and vestibular window abnormalities were only seen in animals treated on day 24. The internal ear exhibited petrosal hypoplasia and delayed ossification of the lateral aspect of the lateral and posterior semicircular canals. Cochlear, vestibular, semicircular, and transcapsular canal defects were confirmed histologically in on

ISSN:0040-3709    

DOI:10.1002/tera.1420230310

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe teratogenic effects of L‐azetidine‐2‐carboxylic acid (LACA) were evaluated in hamsters. Single or multiple intraperitoneal injections of LACA were given on gestational days 7–12. Fetal weights were significantly reduced in several LACA‐treated groups as compared to controls. The frequency of external anomalies was significantly higher than controls in only two LACA‐treated groups: 7.2% in 600 mg/kg on day 12 and 9.6% in 200 mg/kg/day on days 10–12. Subcutaneous hemorrhage and cleft palate were the most frequently occurring externally visible defects. Skeletal anomalies such as retarded ossification, asynchronous vertebral ossification and shortening of bones were found in a high percentage of LACA‐treated fetuses. The major teratological effect of LACA appeared to be the retardation of skele

ISSN:0040-3709    

DOI:10.1002/tera.1420230311

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

年代:1981

数据来源: WILEY