ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00996.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00999.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractMethods for assessing animal neurobehavior following prenatal/perinatal exposures have been in use for almost 20 years and screening tests incorporating them are regulated in three settings: in Japanese Segment II and III studies on drugs, European (EEC/UK) Segment I studies on drugs, and American neurotoxicity studies on chemicals.The methods used in the West for assessing behavior in these contexts at present are described in detail. The evolution of the methods over time, the concepts of apical tests and functional domains, the use of positive control agents, what the U.S. Collaborative Study has shown us, and justification for assessing animal behavior in predicting outcome from human exposures are discussed.

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractMouse embryo culture has been established and applied in the study of the causal mechanisms of abnormal development. Mouse embryo culture can be used as an experimental system to examine the influence of teratogen on early development, together with investigations using developmental engineering such as chimera, transgenic mice and nuclear transfer. We combined mouse embryo culture with embryo transfer and chromosome analysis, and studied the relationship between environmental factors (including maternal factors) and genetic predisposition in developmental abnormalities in the embryos of diabetic mice.In mouse embryo culture from one‐cell to the blastocyst stage, fertilized eggs were incubated in modified Whitten's medium and mixed gas (5% O2, 5% CO2and 90% N2) at 37°C for three days. β‐Mercaptoethanol 20 μM and EDTA‐2Na 100 μM were added in order to overcome “two‐cell block’ in which two‐cell stage embryos could not develop further. Under theses conditions, from 55 to 100% of the cultured one‐cell stage embryos developed into blastocysts depending on the strain.For chromosome preparation, Mikamo and Hamaguchi's method (1975) was modified. This method can be applied from one‐cell to pre‐implantation stage embryos, and allows a higher rate of success (63% of prepared embryos) in preparing chromosome slides than that reported in the literature. Using improved methods of embryo culture, embryo transfer and chromosome analysis, we have obtained evidence that both environmental and genetic factors are the causes of malformation during diabetic pregnancy in mice. Mouse embryo culture associated with chromosome analysis is a useful procedure, and offers important data for the clarification of the causal mechanisms in deve

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractNeuropathological and electrophysiological studies were designed to clarify the pathomechanism of motor disturbance in the hind limbs of rats with sacral agenesis. The model animals were obtained from mother rats which had been treated with trypan blue on day 8 of gestation. Mirror movements in the hind limbs were observed in 7 out of 56 rats with lumbosacral agenesis. The conus medullaris in rats with lumbosacral agenesis ended at the level between Th13‐L1 vertebra, whereas that in normal cases terminated between L3‐4. The spinal cord of the lumbosacral region was hypoplastic and dysplastic particularly in the ventral half. Anterior horn cells were sporadic and there were no apparent median fissure in the spinal cord of the lumbosacral region. On the other hand, any abnormality was not found in the brain, the brain stem, and the spinal cord of the cervicothoracic region. Horseradish peroxidase (HRP) was injected into the unilateral hind limbs. In segments of the anomalous spinal cord, HRP‐labeled neurons in the anterior horn were found not only on the injected side but also on the other side. In electrophysiological examination, F' wave was recorded on the non‐stimulated side with longer latency and duration compared with that of the stimulated side. These morphological and physiological findings indicated that the mirror movements in the hind limbs of the model animals may arise from developmental errors of motor nervous pathway, with some deficient inhibitory mechanism in the upper neural

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractMaternal hyperthermia of short duration had significant short and long term effects on the developing guinea‐pig eye at embryonic days 19, 21 and 23. A marked regionalisation of the heat‐induced effects was observed in the developing retinae, but the lens defects were most obvious following heat at E21 and E23. Bilateral anterior pole cataracts, bipolar zonular cataracts and microphthalmia have been produced following maternal heat stress. It is suggested that these are determined by the cellular events initiated in the developing eye following the teratogenic ins

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb01000.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractHeterotopic glial nodule in the lung is a rare abnormality. Most reported cases are associated with major cranial malformations including anencephaly. The pathogenesis of this condition has not been established. The hypotheses are (1) embolization of glial tissue after head trauma during fetal development, (2) aspiration/implantation of fragments of brain tissue from the amniotic fluid, and (3) aberrant migration of neural crest elements to the lung. This report documents the presence of an intravascular embolus of a glial nodule, which offers support to the embolization theory for the pathogenesis of this peculiar abnormality.

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00782.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00783.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0914-3505    

DOI:10.1111/j.1741-4520.1992.tb00997.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY