摘要:

AbstractA lateral proboscis usually occurs in the region of the inner canthus. We present a case of holoprosencephaly accompanied by an obliquy facial cleft and an anterior encephalocele in which a proboscis lateralis occurred in a very lateral location.

ISSN:0040-3709    

DOI:10.1002/tera.1420400302

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

年代:1989

数据来源: WILEY

摘要:

AbstractFive direct‐acting alkylating agents were examined qualitatively and quantitatively for their ability to produce developmental toxicity in rodent postimplantation embryos. These agents were structurally related and were capable of donating either a methyl (methylnitrosourea, MNU; methylnitronitrosoguanidine, MNNG; methyl methanesulfonate, MMS) or ethyl (ethylnitrosourea, ENU; ethyl methanesulfonate, EMS) group to nucleophiles. These agents' reactivities were known to differ. In day 10 rat embryos in vitro a single, 2‐hour exposure was shown to be sufficient to elicit dose‐dependent increases in embryo lethality and malformations. Qualitatively, the patterns of embryo malformations reported in treated embryos paralleled those observed in in vivo studies, especially in regard to adverse effects on central nervous system and craniofacial systems. Quantitatively, the order of potency of these agents in vitro was: MNNG>MNU>ENU>MMS>EMS. In vivo studies reported a different order of potency. In vitro, methylating agents were consistently more potent than ethylating agents. Other chemical properties such as nucleophilic reactivity or half‐life under physiological conditions could not explain observed potency relationships. Future investigation of other chemical properties of these agents such as specific alkylation and carbamylation reactivities may expand these intial structure‐activity obs

ISSN:0040-3709    

DOI:10.1002/tera.1420400303

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

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper provides an updated, comprehensive, critical review of the epidemiology, genetics, and syndromic aspects of holoprosencephaly and is divided into four parts. In the first part, epidemiologica aspects are discussed under the following headings: prevalence, temporal trends, socioeconomic status, exposure to environmental teratogens, maternal and paternal ages, pregnancy histories, and birth weights. The second part analyzes the facial phenotypes because the genetic and syndromic aspects of holoprosencephaly cannot be understood without knowledge of facial variability and its meaning. Topics discussed include cyclopia, ethmocephaly, cebocephaly, median cleft lip, and less severe facial dysmorphism. The third section, on genetics, analyzes associated anomalies, chromosomal and nonchromosomal holoprosencephaly, family studies, twin studies, genetics of nonsyndromic holoprosencephaly, and recurrence risks. The final section on syndromology summarizes 48 conditions in which some degree of holoprosencephaly may be a feature.

ISSN:0040-3709    

DOI:10.1002/tera.1420400304

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

年代:1989

数据来源: WILEY

摘要:

AbstractDiabetic women are more likely to give birth to infants with congenital malformations than are nondiabetic women. Rodent embryos have been used as a model for the study of abnormal fetal development associated with maternal diabetes, and some of the metabolic factors which are altered in diabetes, such as raised glucose and ketones, have been shown to cause abnormal development of rodent embryos in vitro. The present work explores further the teratogenicity of β‐hydroxybutyrate to rat embryos. To determine the sensitivities of rat embryos at different stages of their development, rat embryos at 9.5 days of gestation have been cultured in vitro for 24 or 48 h, with or without 4 × 10−2M β‐hydroxybutyrate for all or part of the culture period. The ebryos have been examined by scanning electron microscopy, and a detailed morphometric analysis of one tissue, the neuroepithelium, has been undertaken. The results confirm that β‐hydroxybutyrate causes abnormal development of rat embryos. The results of experiments in which embryos were exposed to β‐hydroxybutyrate for only part of a 48 h culture show that embryos expoosed to β‐hydroxybutyrate for a complete 48 h culture are more severely affected than embryos exposed to β‐hydroxybutyrate for only part of the culture and that embryos are more vulnerable to β‐hydroxybutyrate during the first half of a 48 h culture (equivalent to 9.5 to 10.5 days of gestation) than during the second half of a 48 h culture (10.5 to 11.5 days of gestation). The results of experiments in which embryos were cultured with β‐hydroxybutyrate from 9.5 days of gestation for 24 h (equivalent to 9.5 to 10.5 days of gestation) showed that some effects of β‐hydroxybutyrate are already apparent after 24 hours in culture. Many of the abnormalities produced by β‐hydroxybutyrate can be calssified as embryonic retardations rather than malformations—that is, embryos show features characteristic of normal, but younger, embryos. Embryos exposed to β‐hydroxybutyrate for the complete 48 h culture period consume less glucose and produce less lactate than control embryos on a per embryo basis, but not on a per μg protein basis, suggesting that the reduced metabolism is an effect of β‐hydroxybutyrate‐induced developmental delay rathen than a cause of it. Morphometric analyses of the shapes of the cells of the neuroepithelium show that the cells are less elongated/tapered in β‐hydroxybutyrate‐treated embryos than in control embryosd; these differences are characteristic of embryos in which the elevation of the neural fold has been inhibited. The mechanisms by which developmental retardation might lead to fetal malformation are discussed, with special

ISSN:0040-3709    

DOI:10.1002/tera.1420400305

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

年代:1989

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420400306

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

年代:1989

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420400307

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

年代:1989

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420400308

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

年代:1989

数据来源: WILEY

ISSN:0040-3709    

DOI:10.1002/tera.1420400301

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

年代:1989

数据来源: WILEY