摘要:

AbstractData for estimating equivalent ages of rat, mouse and chick embryos are presented, using several sources from the literature. When the time of development of various embryonic structures is matched for the three species, the differences in time for the stages are primarily due to delays in development of the preimplantation blastulas of the rat and mouse in comparison with the incubated chick egg. Development from the blastula stage to completion of major organogenesis proceeds at approximately the same rate for all three species.

ISSN:0040-3709    

DOI:10.1002/tera.1420190302

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

年代:1979

数据来源: WILEY

摘要:

AbstractAdministration of excess vitamin A during gestation results in gross malformations of the fetus. It has been proposed that the mechanism of action of vitamin A in producing malformations is through a reduction in DNA synthesis and altered cellular differentiation. A similar mechanism has been suggested for the teratogenic effect of zinc deficiency. The simultaneous treatment of pregnant rats with excess vitamin A (3,000 or 30,000 IU/day) and low dietary zinc (0.4 or 9 ppm) resulted in a high incidence of fetal malformations from each treatment with no discernible interaction. Both treatments resulted in brain deformities, but zinc deficiency caused a higher incidence of lung and tail malformations and a general reduction in the uptake of3H‐thymidine into embryonic DNA. The administration of excess vitamin A resulted in a higher incidence of fetal eye and palate anomalies than did zinc deficiency but had no effect on DNA synthesis. The lack of interaction between the treatments with regard to fetal malformations, the differences in the types of organs which were affected by the two treatments, and the reduction in DNA synthesis by zinc deficiency but not by vitamin A excess suggest that these conditions alter development through different mechanism

ISSN:0040-3709    

DOI:10.1002/tera.1420190303

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

年代:1979

数据来源: WILEY

摘要:

AbstractElectron microscopic examination of embryos from trypan blue injected maternal rats reveals tissue alterations that may signal forthcoming malformations. Ten‐, eleven‐, and twelve‐day normal appearing embryos from the dye‐treated group demonstrate early tissue changes in hindgut, neural tissue and myocardium. A 1‐μ “halo” vacuole is observed only in treated tissues. The vacuole exhibits a clear periphery enclosing a homogeneous, electron‐dense material. The vacuole is prevalent throughout 10‐day embryonic tissues. In older embryos the halo vacuole is frequently observed within residual bodies, suggesting heterophagic processing. The halo vacuole may contain trypan blue, implicating direct action of the dye upon embryonic cells. Extensive fibrous deposits above the neural plates and within hindgut lumina of dye‐treated embryos demonstrate 230 Å periodicity characteristic of fibrin. In cross‐section the fibrin displays a core of fibrillar material encased by an electron‐dense sheath. Trypan blue may form this core and initiate fibrin polymerization. These extensive accumulations of fibrin probably form in conjunction with dye provoked hemorrhagic blistering. Large intra‐ and extracellular granular deposits occur in dye‐treated myocardium and hindgut epithelium. PAS staining, alpha amylase and ribonuclease digestion identify the granules as glycogen. The ultrastructure and quantity of glycogen is similar to that in gl

ISSN:0040-3709    

DOI:10.1002/tera.1420190304

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

年代:1979

数据来源: WILEY

摘要:

AbstractC57BL/6J mice were fed a liquid diet in which 17, 25, or 30% of the calories were derived from ethanol from the fifth through the tenth day of gestation. Control mice were fed lab chow or pair‐fed identical diets, except that sucrose substituted isocalorically for ethanol. At term the fetuses were removed and. following fixation, examined by microdissection. The incidence of fetal resorptions and congenital malformations increased in a dose‐related manner. Anomalies included skeletal, neurological, urogenital, and cardiovascular systems. These data indicate that in mice, an alcohol diet which is adequate in vitamins and protein results in increased fetal wastage and birth defe

ISSN:0040-3709    

DOI:10.1002/tera.1420190305

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

年代:1979

数据来源: WILEY

摘要:

AbstractUnusual musculotendinous abnormalities were observed in the forelimbs of a rhesus monkey treated prenatally with thalidomide (10 mg/kg maternal body weight, gestation days 33, 34, and 35). Although the hindlimbs exhibited malformations typical of thalidomide dysmelia, the forelimbs appeared relatively normal externally. However, dissection revealed totally anomalous insertions of preaxial muscles of both forearms. Extensor muscles inserted on flexor surfaces even though normal sites of insertion were present and unoccupied. Radiographs revealed only minor ossification deficiencies in the carpus and distal radius. These observations suggest that thalidomide, given at the appropriate time, can disrupt condensation and splitting of pre‐muscle masses without greatly disturbing condensation of corresponding pre‐skeletal elements. These types of musculoskeletal relationships are unusual findings in congenital malformations of the limbs and have not been widely associated with thalidomide teratogene

ISSN:0040-3709    

DOI:10.1002/tera.1420190306

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

年代:1979

数据来源: WILEY

摘要:

AbstractThese studies evaluated the teratogenic potential of indole‐3‐acetic acid (IAA), a naturally occurring plant hormone, in CF‐1 mice and Sprague‐Dawley rats. Mice were given 5, 50, 200, or 500 mg IAA/kg/day by gavage on days 7 through 15 of gestation. Rats were given 50, 200, or 500 mg IAA/kg/day by gavage on days 7 through 15 of gestation. IAA was teratogenic in mice and rats at 500 mg/kg/day; cleft palate was induced in both species at this dose level. In mice, other malformations including exencephaly, ablepharia, dilated cerebral ventricles, and crooked tail were also observed. Mice given 500 mg/kg of IAA gained less weight than control mice during gestation; no evidence of maternal toxicity was observed in rats. IAA did not cause fetal resorptions in either species and was not teratogenic at dose levels below 50

ISSN:0040-3709    

DOI:10.1002/tera.1420190307

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

年代:1979

数据来源: WILEY

摘要:

AbstractAs a part of a series of investigations into the structural and functional consequences of interference with cell proliferation, mice were treated with 5‐azacytidine during two stages of early fetal life. Treatment on either the twelfth or fourteenth day of gestation led to permanent significant reductions in body weight and brain weight. Behaviorally, the earlier treatment was associated with a delay in development of the righting reflex, permanent deficits in locomotor coordination, and hypoactivity. Treatment on the fourteenth day of gestation led to decreased passive avoidance, increased active avoidance, and hyperactivity — the same syndrome observed after treatment on the eighteenth day. Both treatments led to abnormal behavior on a spatial maze task. The developmental outcome of injuries induced in the early fetal period appears similar to the outcome of injuries at later stages of developm

ISSN:0040-3709    

DOI:10.1002/tera.1420190308

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe lumbosacral region of the neural tube was studied by means of transmission electron microscopy in retrospectively confirmed normal ( + /+ Sp/ + ) and abnormal (Sp/Sp) embryos of the splotch mutant mouse early on the ninth day of gestation when the caudal neural groove is normally in the process of closing to form the neural tube. In abnormal embryos, a consistent feature is the presence of gap junctional vesicles, particularly in the region of the neural groove which subsequently fails to close, whereas these structures are rarely observed in similar areas of normal embryos. The possible significance of gap junctional vesicles is discussed in terms of cellular adhesion during early neurogenesis.

ISSN:0040-3709    

DOI:10.1002/tera.1420190309

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe relationship between the teratogenicity of EM12, 2‐(2,6‐dioxopiperiden‐3′‐yl) phthalimidine, a stable analogue of thalidomide, and zinc status in the maternal animal was investigated using pregnant rats on a low‐zinc diet (1 ppm zinc, days 0–14 gestation) as the experimental model.Previous studies with this compound in rats fed a commercial diet at oral doses up to 250 mg/kg per day for three days and intravenous doses up to 10 mg/kg per day for three days failed to produce “typical” thalidomide malformations. However, when a dose of 150 mg/kg was given intraperitoneally to rats on a low‐zinc diet, typical thalidomide malformations occurred with an

ISSN:0040-3709    

DOI:10.1002/tera.1420190310

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

年代:1979

数据来源: WILEY

摘要:

AbstractNine‐day chick embryos were treated with 4‐methylum‐belliferyl β‐D‐xyloside or β‐aminopropionitrile fumarate, and their gross chemical composition was examined one week later. Total DNA was 10–20% less in embryos treated with either drug than it was in control embryos. Xyloside‐treated embryos showed marked increases in percent wet weight and in sodium/DNA and chloride/DNA ratios, and small decreases in protein/DNA, hydroxyproline/DNA and sulfate/DNA. None of these parameters was affected in embryos treated with β‐aminopropionitrile. Approximately 85% of the uronic acid of control embryos was present as chondroitin sulfate, with a degree of sulfation of 80% and charge density of 1.8; all of this chondroitin sulfate was covalently linked to peptide and had a number‐average molecular weight of 29,300. In embryos treated with β‐xyloside, 90% of the uronic acid was present as chondroitin sulfate, with a degree of sulfation of 40% and charge density ranging from 1 to 2; 27% of this chondroitin sulfate, with an average molecular weight of 25,400, was peptide linked, while 73% was linked to 4‐methylum‐belliferone arid had an average molecular weight of 22,900. The chemical differences between embryos treated with the xyloside and embryos treated with the lathyrogen reinforce the conclusion on morphological grounds that these are distinct syndromes involving different aspect

ISSN:0040-3709    

DOI:10.1002/tera.1420190311

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

年代:1979

数据来源: WILEY