ISSN:0040-3709    

DOI:10.1002/tera.1420200203

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

年代:1979

数据来源: WILEY

摘要:

AbstractPhysicians' interest in congenital malformations has varied greatly during the last two centuries. After an acme in the 19th century, teratology was of little interest to the medical profession during the first four decades of the 20th century. Since then a variety of events have again made birth defects important. An attempt is made to explain the waxing and waning of the physicians' attention to this age‐old proble

ISSN:0040-3709    

DOI:10.1002/tera.1420200204

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe beginnings of mammalian experimental teratology in this century are briefly reviewed and it is noted that prior to 1960 a degree of sophistication in concept and technology had already been achieved. Thus, contrary to claims that teratology had its beginning with the thalidomide catastrophe, a modest but expanding activity and body of knowledge already existed before this unfortunate event.This activity and this knowledge, however, were largely confined to academic and research institute laboratories and made little impact on the agencies in medicine, government and industry which oversaw public health and safety and set policies intended to preserve them. No individual, group, or agency can rightly be blamed for not having sooner brought together the concepts and methodology needed for meaningful animal testing and the regulatory insight and experience needed intelligently to apply test data to human safety evaluation. To accomplish this liaison seems to have required the largest toxicological catastrophe yet recorded in human history.The major events leading to formulation of the first standardized guidelines are reviewed, but it is emphasized that even today the best animal testing can only provide a limited statement of probability regarding human risk vis‐à‐vis sa

ISSN:0040-3709    

DOI:10.1002/tera.1420200205

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe A family of inbred mice which originated in 1921, came during its early development to have incorporated into its genome the tendency to several congenital malformations, among them cleft lip and palate. These sporadic abnormalities are of interest because they closely resemble their human counterparts in morphology and development, and because they share with them a multifactorial basis. The origins and development of the A family are traced, and the abnormalities are described and the forces affecting them detailed.

ISSN:0040-3709    

DOI:10.1002/tera.1420200206

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

年代:1979

数据来源: WILEY

摘要:

AbstractAn infant, horn to unrelated parents, who had a rugated perineal mass which measured 17 cm in diameter is reported. No external genitalia or anal orifice was identified although the infant voided from a 5 mm crevice on the caudal surface of the mass. The patient died at four weeks of age. The perineal mass was made up of two separate sacs. The anterior sac resembled a urinary bladder in which two ureteral and a single vaginal orifice were identified. The posterior sac was continuous with the peritoneal cavity and contained bowel, left ovary, uterus and right kidney. The left kidney was small, polycystic and the right gonad a streak.

ISSN:0040-3709    

DOI:10.1002/tera.1420200207

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

年代:1979

数据来源: WILEY

摘要:

AbstractIn teratogenic studies toxic effects may manifest themselves in retarded fetal development, such as a reduction in fetal weight. In searching for an additional index, the number of centers of ossification in seven skeletal districts (sternum, metacarpus, metatarsus, cervical and caudal vertebrae, anterior and posterior proximal phalanges) of rat fetuses delivered on days 19, 20 and 21 of gestation were counted and compared. Results showed uneven ossification in day‐19 and ‐20 fetuses, but sufficiently advanced, homogeneous an uniform ossification in day‐21 fetuses to provide a reliable quantitative index for evaluating retarded fetal development. It is therefore proposed that the stage of skeletal ossification in day‐21 fetuses be used in teratogenic studies in the rat to evaluate retarded fetal deve

ISSN:0040-3709    

DOI:10.1002/tera.1420200208

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

年代:1979

数据来源: WILEY

摘要:

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 ascertai

ISSN:0040-3709    

DOI:10.1002/tera.1420200209

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe process of palate shelf elevation has been analyzed by light microscopy in mouse embryos cultured in vitro. The observations presented correlate changes in cell shape and orientation in the palate with the morphogenetic movement of the shelf. These studies suggest that in addition to any physical‐chemical force elevating the shelf an active contraction of specific palate cells could also aid the process. Contribution to elevation could be derived from masses of contracting cells from the previously described non‐muscle contractile systems in posterior (region 2) and mid‐anterior (region 3) palate as well as other peripheral mesenchymal cells. Finally, elongation and contraction of the tongue side epithelial cells may also play a role in palate elev

ISSN:0040-3709    

DOI:10.1002/tera.1420200210

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

年代:1979

数据来源: WILEY

摘要:

AbstractOn day 14 of pregnancy, rats were injected i.p. with 9.5 mg/kg of chlorambucil. At term, all the fetuses were stunted and had obvious skeletal malformations. From days 15‐‐20 of gestation there was a steady progression of cell death and histologic derangement in long bone formation. This began on day 15, the day following exposure to chlorambucil, with extensive cell death of chondroblasts in the long bone primordia. By day 16, dead or dying cells were located in the cartilage model and became associated with a higher than normal matrix to cell ratio. In day 17 limbs, many cells of the cartilage model were irregular in size and shape so that the normally precise cellular arrangement was lacking. On day 18, periosteal and enchondrial calcification was delayed and scanty. The fibular hemimelia observed in all drug‐treated term fetuses stained with alizarin appeared to result from lack of development of the proximal half of the cartilage model. The observed alterations, particularly bowing of the ulna, in the teratogen‐treated fetuses appeared to result primarily from specific cell death and formation of aberrant cell types but abnormal cell products may also play

ISSN:0040-3709    

DOI:10.1002/tera.1420200211

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

年代:1979

数据来源: WILEY

摘要:

AbstractHistologic sections were made of the forelimbs of day 10 to 12.5 embryos removed 3, 16, 30, 36, 42, 45, 63 and 75 hours after the intraperitoneal injection of acetazolamide into C57B1/6J pregnant females. A postaxial deformity was first visible in the right forelimb of day 10.9 embryos 36 hours after the second dose of acetazolamide 1,000 mg/kg on day 9 of gestation. The deformity was a postaxial deficiency of mesenchyme tissue without any evidence of cell necrosis. The deformity was present before aggregation of mesenchyme cells occurs as the first step in chondrogenesis. The pattern of cell orientation in the adjacent mesenchyme aggregate of a deformed day 12.5 forelimb was normal. This means that the primary effect of acetazolamide is not on the formation of precartilage aggregates in the postaxial region, but involves other aspects of early limb development.

ISSN:0040-3709    

DOI:10.1002/tera.1420200212

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

年代:1979

数据来源: WILEY