ISSN:0040-3709    

DOI:10.1002/tera.1420200103

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

年代:1979

数据来源: WILEY

摘要:

AbstractAn indirect method, based on placental morphology, was used to establish the incidence of heteroploidy in early human pregnancy and to determine the possible effect of the IUD on its occurrence. The non‐IUD‐wearing control population, comprised of 5,779 healthy fertile women undergoing therapeutic abortion for socioeconomic reasons, yielded an incidence of heteroploidy of 0.83% as compared with an overall incidence of 46.7% in our group of spontaneous aborters. In contrast heteroploidy was never detected pathologically in IUD‐associated spontaneous and therapeutic abortions. It was concluded that the IUD significantly prevented the development of heteroploid conceptuses. The biological and clinical significance of these findings was disc

ISSN:0040-3709    

DOI:10.1002/tera.1420200104

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

年代:1979

数据来源: WILEY

摘要:

AbstractAcetyl‐ and butyrylcholinesterase activities were investigated in muscle, brain, blood plasma and erythrocyte membranes obtained from adult and fetal mice of different genotypes ( + / +, +/mdg, +/?, andmdg/mdg) with respect to the muscular dysgenesis (mdg) mutant gene. The study revealed that both AChE and BChE are present in muscle, brain and plasma, whereas erythrocyte membranes exhibit only AChE activity. Significantly lower (P<0.05) AChE activity was observed in thigh muscle of 20‐day‐old fetuses homozygous for the mutant gene, compared with muscles of wild ( + / + ) and unknown genotypes ( + /?). The mutant (mdg/mdg) fetuses had a slightly significantly (P<0.05) depressed level of AChE activity in brain tissue, as compared to fetuses of unknown genotype ( + /?). AChE activity was higher (P<0.05) in the plasma of (mdg/mdg) fetuses than in that of fetuses of unknown genotype ( + /?) but did not differ significantly from those of wild type ( + / + ) fetuses. Samples of the same tissues were subjected to zone electrophoresis, for investigating patterns of cholinesterase isozymes, non‐specific esterases and total protein. Two distinct bands and a faster moving series of poorly resolved bands of acetylcholinesterase were found in muscle and brain of phenotypically normal fetuses. One of the main bands and the diffuse bands were absent in muscle and the diffuse bands were reduced in brain of homozygous (mdg/mdg) mutant fetuses. Except for increased Coomassie blue staining of a few bands in muscle, gels stained for AChE in other tissues, for BuChE, for alpha naphthyl esterase and for total protein showed no differences between mutant and control fetuses. No differences in any electrophoretic patterns were detected between heterozygous ( + /mdg) and homozygous wild type

ISSN:0040-3709    

DOI:10.1002/tera.1420200105

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

年代:1979

数据来源: WILEY

摘要:

AbstractBehavioral alterations have been reported following perinatal exposures to a variety of agents. If subtle effects of this type are to be detected and prevented, sensitive and appropriate measures are needed for prospective screening of new compounds. However, studies reported in the literature have used differing exposure regimens, postnatal environmental conditions and behavioral testing procedures thus making it difficult to determine which existing techniques have particular relevance to screening new drugs and chemicals. It is imperative that such techniques be identified or new ones be developed for screening purposes, as the incorporation of behavioral evaluation into regulatory guidelines and protocols is being considered seriously. Before behavioral assessment can become a meaningful aspect of a routine screening system, considerable research and development must occur. The objectives of such a behavioral screen must be defined. Procedural standardization must be included in efforts to identify those methods which: (1) yield reproducible results within and across laboratories; (2) are sensitive to alterations produced by a range of agents; (3) are predictive of effects in man; (4) are cost‐efficient. Identification of positive control agents, critical periods for testing and early indicators of behavioral dysfunction is urgently needed. The utility of pharmacologic/environmental challenges in unmasking functional abnormalities, and the possibility of multitesting interactions should be investigated. As the resources necessary to accomplish such a task are enormous, it is imperative that behavioral teratologists from academia, industry and government work together during all phases of such development. Interlaboratory cooperation in standardization, validation and interpretation of test methods and results is especially encourage

ISSN:0040-3709    

DOI:10.1002/tera.1420200106

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

年代:1979

数据来源: WILEY

摘要:

AbstractCongenital low‐dose exposure of rat fetuses to methylmercury produced smaller offspring without anatomical abnormalities. The present study explored the mechanisms of the smallness of fetuses. The pregnant rats were given methylmercury water (25 ppm) from day 1 of pregnancy continuously until day 20 of gestation. There was a negative correlation of fetal weight and maternal and fetal mercury burden. The whole organ DNA and protein content of the livers and kidneys in the experiments were significantly lower than the control (P<0.05) indicating that there were fewer cells per organ in the mercury exposed fetuses. When the data were compared on a per gram of tissue basis, there was no significant difference, indicating that the number and size of the cells of each were not diminished. The incorporation of3H‐thymidine into fetal tissue DNA was also substantially lower in the experimental group indicating decreased proliferative activity. We conclude from this study that, at least for some major organs, the decreased size in the mercury exposed fetuses is due to fewer cells in the organs due to decreased proliferative activ

ISSN:0040-3709    

DOI:10.1002/tera.1420200107

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

年代:1979

数据来源: WILEY

摘要:

AbstractA high percentage of cleft palates can be induced in rat fetuses by a single injection of the glutamine analog diazo‐oxo‐norleucine (DON) on day 15 of gestation. The purpose of this study was to evaluate the effects of DON in vivo on craniofacial growth and spatial relations in order to identify factors that may contribute to the palatal defects. Sprague‐Dawley rats in the experimental groups were given a single IP injection of 2.0 mg DON (6 mg/kg maternal body weight) on day 15 and were killed on day 16 or 17. Control fetuses were collected on days 15, 16 and 17. Fetal heads were fixed in Bouin's solution, embedded in Paraplast and serially‐sectioned. Midsagittal and coronal sections were projected at 30 × and a series of linear and angular measurements were made. DON had limited effect on growth of the cranial base, nasomaxillary complex, and palatine processes, but dramatically reduced the length of Meckel's cartilage. Treatment with DON delayed shelf elevation approximately 24 hours, and tongue position remained high in the oronasal cavity. Growth retardation in Meckel's cartilage therefore may contribute to delayed shelf movement by retarding downward and forward positioning of the tongue‐mandibul

ISSN:0040-3709    

DOI:10.1002/tera.1420200108

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

年代:1979

数据来源: WILEY

摘要:

AbstractPregnant Rhesus monkeys were infected via instillation of influenza, mumps and western equine encephalomyelitis viruses respectively into the amniotic sacs at approximately 90 days gestation to determine if fetal infections would occur. Virus was recovered from fetal tissues after seven days in 100% of the exposed animals. Thus, the viruses are capable of causing fetal infection.Rhesus monkey fetuses were inoculated with influenza, mumps and WEE viruses by the direct intracerebral route at approximately 90 days gestation to determine possible teratogenicity of the viruses. Influenza virus caused no malformations or measurable fetal effects. Mumps virus resulted in significant fetal mortality. WEE virus resulted in a 100% incidence of encephalitis and hy‐drocephalus. Thus, mumps and WEE viruses are teratogens in primates and are potential teratogens of ma

ISSN:0040-3709    

DOI:10.1002/tera.1420200109

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

年代:1979

数据来源: WILEY

摘要:

AbstractPregnant Rhesus monkeys were infected via installation of Western Equine Encephalomyelitis (WEE) vaccine virus into the amniotic sacs at 50 and 80 days gestation to determine if the resulting infections would produce fetal mortality or fetal malformations, particularly within the central nervous system.Of those receiving virus at 50 days gestation, 13 of 18 fetuses were aborted or dead in utero at time of Caesarean section; 2 of 18 were malformed (hydrocephalus and polyarthrosis); and 3 of 18 were anatomically normal. Of those receiving virus at 80 days gestation four of eight fetuses were aborted or dead in utero at time of Caesarean section, one of eight was malformed (hydrocephalus) and three of eight were anatomically normal. Three of three controls receiving neutralized virus at each gestational age were anatomically normal. Fetal WEE vaccine virus infection significantly increased fetal mortality and resulted in a significant incidence of fetal malformations.

ISSN:0040-3709    

DOI:10.1002/tera.1420200110

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

年代:1979

数据来源: WILEY

摘要:

AbstractTwo children from a small Amerindian community presented with profound retardation, initial hypotonia progressing to hypertonia, scaphocephaly, a prominent occiput, poor postnatal head growth, and additional minor anomalies. Abuse of gasoline by inhalation was a widespread problem in the community, and gasoline inhalation during the pregnancy could be documented in both of the pregnancies. We are raising the question as to whether inhalation of gasoline during pregnancy may be teratogenic in humans.

ISSN:0040-3709    

DOI:10.1002/tera.1420200111

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

年代:1979

数据来源: WILEY

摘要:

AbstractSecondary cartilage fails to differentiate on membrane bones of embryonic chicks which have been paralyzed by the in ovo injection of Dtubocurarine chloride at ten days of incubation. A planimetric analysis of serial sections of a membrane bone (the quadratojugal) from control (mobile), and from paralyzed embryos, indicated that osteogenesis was not slowed in paralyzed embryos. However the rate of accumulation of periosteal progenitor cells was significantly lower in paralyzed than in mobile embryos. Quantitative analysis of3H‐thymidine‐labelled progenitor cells indicated that the slowed accumulation of progenitor cells was the result of fewer progenitor cells initiating DNA synthesis and mitosis. Between 10 and 11 days of incubation, 60 to 75 more3H‐thymidine‐labelled progenitor cells accumulated in mobile embryos than accumulated on each quadratojugal in paralyzed embryos. This subpopulation of cells could represent the chondroprogenitor cells which produce secondary cartilage in mobile embryos. If this is so, then biomechanical factors control the ability of the embryo to produce secondary cartilage by allowing the selective accumulation of chondrogenic progenito

ISSN:0040-3709    

DOI:10.1002/tera.1420200112

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

年代:1979

数据来源: WILEY