摘要:

AbstractBiochemical analysis of a lethal recessive mutation affecting chondrogenesis in mice further delineated the mechanism by which this pleiotropic gene acts. Cartilage from late fetuses homozygous for chondrodysplasia (cho/cho) were terminally labeled in vitro with Na235SO4, [14C] glucosamine, and [14C] glucose. Rates of precursor incorporation; tissue contents of uronic acid, amino sugar, and protein; and molecular weight of glycosaminoglycan were determined and found normal compared with control littermate cartilage. Samples from mutants, agitated overnight in distilled water and assayed for loss of incorporated35S, showed between 47 and 77% of control activity. The rinse water from mutant cartilage contained correspondingly more35S than did control. Chromatographic analysis of both tissue‐bound and water‐diffusible macro‐molecules confirmed that glycosaminoglycan and protein backbone were intact. Because the molecular content and rates of precursor incorporation were normal the results suggested that thechogene does not alter net synthesis of glycosaminoglycan. The observation that water facilitates extraction of a glycosaminoglycan‐protein complex of normal molecular weight suggests that the defect in chondrogenesis results from defective interaction of proteoglycan and some other matrix constituent. In view of a previous report that collagen fibrils of mutant cartilage are atypically large and natively banded the site of chondrogenic defect might be the interaction between proteoglycan and c

ISSN:0040-3709    

DOI:10.1002/tera.1420130312

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

年代:1976

数据来源: WILEY

摘要:

AbstractRana pipiensembryos at the cleavage, blastula, gastrula, and neural‐plate stages of development were treated with methylmercuric chloride in concentrations of 0.5–200 parts per billion (ppb) to determine embryocidal and teratogenic effects. Concentrations of 40 ppb and above were lethal to embryos treated during the cleavage stage. Embryos at the blastula, gastrula, and neural‐plate stages were treated for 5 days with 5–30 ppb; 5 ppb had only minor effects, 10, 15, and 20 ppb caused various defects (exogastrulae, poor tail development, poor general development) and increased death rates related to exposure time and concentration, and embryos treated with 30 ppb had a high frequency of defects after 24 h and all died by the end of the 3rd day. Individual tolerances to methylmercury of various degrees were o

ISSN:0040-3709    

DOI:10.1002/tera.1420130313

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

年代:1976

数据来源: WILEY

摘要:

AbstractA male human fetus of 83 mm crown‐rump length was removed by hysterotomy from a diabetic woman. It was normal externally but had bilateral kidney agenesis, a hypoplastic left heart, vertebral fusion on the left side, and other cervical and thoracic vertebral and rib anomalies. Possible syndromes and their relevance to prenatal diagnosis are discusse

ISSN:0040-3709    

DOI:10.1002/tera.1420130314

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe heart and great vessels of 1286 human embryos were microdissected and examined for malformations. Most of the embryos were obtained by induced abortion conducted for socioeconomic reasons and the remainder by hysterectomy performed because of some minor disturbance. Only embryos that were alive in utero, at Carnegie stages 18–23, and showed no external anomalies were included. A microdissection procedure that enables precise examination of the heart was used. Criteria for diagnosis of such defects as ventricular septal defect, stenosis, and coarctation were established. Twenty‐seven (2.1%) embryos with congenital cardiovascular malformation (CCM) were found. The frequency was higher than that (0.46–1.17%) reported for newborns. The defects included most of the comparatively common types of CCM, and it was confirmed that the major types of CCM are manifested early in life. It was also noted that certain severe types of anomaly, reported to be scarce in infants, are relatively common in em

ISSN:0040-3709    

DOI:10.1002/tera.1420130315

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

年代:1976

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420130316

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

年代:1976

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420130318

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

年代:1976

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420130301

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

年代:1976

数据来源: WILEY