ISSN:0040-3709    

DOI:10.1002/tera.1420140102

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

年代:1976

数据来源: WILEY

摘要:

AbstractFrom anatomical and cytogenetic studies of 1500 spontaneous abortuses attempts were made to establish correlations between the phenotype and karyotype of the specimens. The criteria used to determine the phenotype were based on estimated developmental age and macroscopic and microscopic examinations of embryo and placenta. Main features were described permitting, on anatomic examination of the conceptus, diagnosis of genetic anomalies, and in some instances possibly assigning the type of chromosomal aberration: viz., in monosomy X, triploidies, tetraploidies, and some trisomies. Phenotypic expression at the cellular level was studied by morphometry of the placenta and by study of in‐vitro growth characteristics of cells lines initiated from aneuploid embryos. Study of growth rate characteristics may reveal the basis for the pathogenesis of developmental arrest

ISSN:0040-3709    

DOI:10.1002/tera.1420140103

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

年代:1976

数据来源: WILEY

摘要:

AbstractPregnancy was timed in cats following induced ovulation. Methotrexate, (0.5 mg/kg), aminopterin, (0.1 mg/kg), and acetylsalicylic acid, (25 or 50 mg/kg) were administered orally in gelatin capsules in single daily doses on different days of gestation, methotrexate (MTX) on days 11‒14, 14‒17, or 17‒20, aminopterin on day 12, 14, or 16, and acetylsalicylic acid (ASA) on days 10‒15 or 15‒20. Maternal toxicity was produced only by MTX. MTX given on days 11‒14 and 14‒17 produced high frequencies of malformations including umbilical hernia. Aminopterin caused no conclusive teratogenic response. An overall increased frequency of anomalies occurred after 50 mg/kg ASA but no single anomaly

ISSN:0040-3709    

DOI:10.1002/tera.1420140104

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

年代:1976

数据来源: WILEY

摘要:

AbstractRecords of children with Down syndrome (DS) at the BC Health Surveillance Registry were linked to their Birth Registrations to derive maternal ages. Incidence and maternal‐age specific rates were calculated for 1952‒73. Mean maternal age has declined both for normal and DS children, the latter to a marked degree, so that in 1972‒73 80% were horn to women under 35 years. Using maternal age of 40 and over as an indication for amniocentesis would only detect 10% of DS children. The crude incidence rate (mean 1.28/1000 livebirths) has not changed appreciably over the study period except for 1969 in which a statistically significant peak occurred. The standardized rate showed an increasing trend but it is not clear whether this was a true biological increase or resulted from better ascertai

ISSN:0040-3709    

DOI:10.1002/tera.1420140105

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

年代:1976

数据来源: WILEY

摘要:

AbstractIt was proposed that embryonic face shape is one of the quantitative variables underlying the threshold trait, cleft lip. To test the hypothesis several facial dimensions were measured in photographs of embryos at an early stage of formation of the face in 3 lines of mice. The lines had been selected from one original population using frequency of cleft lip induced by 6‒aminonicotinamide as the selection criterion. Line L was susceptible to spontaneous cleft lip; lines M and C were not. Line L had a significantly smaller distance between the nasal pits than the other 2 lines, but did not differ in overall head size. A trend towards reduced angle between the medial nasal processes in the L line was noted, though this was not statistically significant. These results were predicted by the face‐shape hypothe

ISSN:0040-3709    

DOI:10.1002/tera.1420140106

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe teratogenicity of β‐aminopropionitrile (βAPN) was evaluated in golden Syrian hamsters; single doses of 1250, 2500, and 3750 mg/kg given on days 7‒13 produced fetal mortality, growth retardation and malformations. All time‐dose combinations produced gross external abnormalities with the highest rate (92.5%) occurring following day‐12 treatment. High frequencies of skeletal abnormalities including deformities of the ribs, fibula, and scapula occurred after days‐10‒12 treatment. Deformed ribs occurred in 100% of fetuses exposed on day ll to any of the dosages. The types of abnormality generally resembled those produced by lathyrogens in other species except for exencephaly and encephalocele, which occurred after treatment on day 7. These results indicate that βAPN is a typical teratogen, capable of producing abnormalities of the central nervous system early in gestation, and may reflect a broader mechanism for its activity than previo

ISSN:0040-3709    

DOI:10.1002/tera.1420140107

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

年代:1976

数据来源: WILEY

摘要:

AbstractTo determine whether there is transplacental passage of retinoic acid (vitamin A acid) or its metabolites levels of radioactivity were measured in embryos after administration to 12th‐day pregnant ICR/DUB mice of nonteratogenic or teratogenic quantities of [3H]retinoic acid. After the former treatment radioactivity was demonstrable in embryos, placentas, and visceral yolk sacs (VYS) at 1 h after treatment. Expressed in terms of radioactivity per unit protein content, embryos at 1 h had about one‐third as much radioactivity as maternal livers. The placentas had maximum radioactivity at 2 h, whereas embryos and VYS accumulated maximum levels by 6 h after treatment. At 6 h the level in embryos was twice that in placentas. After teratogenic treatment placentas and embryos attained peak levels of radioactivity at 6 and 12 h later, respectively. Again, embryos at peak level contained 2‐3 times as much radioactivity as placentas or VYS. The amount of retinoic acid, metabolites, or both, in embryos after the teratogenic treatment, calculated on the basis of specific activity of the injected label, was 26 times greater than after nonteratogenic treatment; the amount in maternal liver was 75 times greater. The results support previous evidence that the teratogenic effects of retinoic acid are associated with raised levels of retinoic acid, its metabolites, or both, in em

ISSN:0040-3709    

DOI:10.1002/tera.1420140108

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

年代:1976

数据来源: WILEY

摘要:

AbstractAttempts to culture postimplantation rat embryos on defined media have not been successful although they grow well when cultured on homologous serum. As a first step in the search for factors in serum that support growth and differentiation of such cultured preparations the following experiments were undertaken. Six‐somite rat embryos were cultured on whole serum, dialyzed serum, or the buffered salt solution (BSS) used for dialysis. Additional experiments were conducted utilizing BSS supplemented with glucose or dialyzed serum supplemented with glucose, mannose, fructose, or pyruvate. Of the media tested only glucose‐supplemented dialyzed serum maintained development at a level comparable to that obtained with whole serum. Further preliminary studies with combined supplementation and metabolic poisoning suggested that anaerobic glycolysis is essential for the in‐vitro growth and differentiation of these prepara

ISSN:0040-3709    

DOI:10.1002/tera.1420140109

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

年代:1976

数据来源: WILEY

摘要:

AbstractThalidomide was administered to pregnant rabbits in dosages of 150–250 mg/kg/day on days 8–12 of gestation. These females produced 40 offspring, 21 of which were deformed. Four control females produced 34 offspring, none of which was deformed. The C6 and C7 ganglia of day‒13, ‒15, ‒17, and ‒21 control and experimental embryos and fetuses were examined electron microscopically. Degenerative changes were found in the neurons and axons of dorsal root ganglia in day‒13 experimental embryos, i.e., at least 16 h before the earliest signs of thalidomide dysmelia have been reported in rabbits (Vickers, '67). Since the dorsal root ganglia form in rabbits on days 11 and 12 the changes evident at day 13 indicate that degeneration of neurons and axons may be a pathogenetic factor in thalidomide‐induced periphe

ISSN:0040-3709    

DOI:10.1002/tera.1420140110

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

年代:1976

数据来源: WILEY

摘要:

AbstractChick embryos were explanted at HH stage 4 and cultured for 24 h on thin albumen with 10 μg/ml 5‐bromodeoxyuridine (BrdU). BrdU inhibited closure of the neural tube in over 90% of the embryos. Mitotic figures were found throughout adversely effected neuroepithelium, suggesting that interkinetic nuclear migration had been inhibited. Electron microscopic studies of BrdU‐treated neural‐tube cells showed fewer and more amorphous cytoplasmic extensions, microfilaments, and desmosomal (functional) tonofibrils than in controls, but micro‐tubules were un

ISSN:0040-3709    

DOI:10.1002/tera.1420140111

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

年代:1976

数据来源: WILEY