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81.
In a longitudinal prospective study of 1,529 women pregnant in 1974-1975, aspirin and acetaminophen were the two medications most frequently taken during the first half of pregnancy (46 and 41%, respectively). In a selected cohort of 421 offspring of these women, examined at 4 years of age, maternal aspirin use during the first half of pregnancy was significantly related to IQ and attention decrements in the exposed children. Multiple regression analyses were used to statistically adjust for a variety of potentially confounding factors including demographic characteristics, child characteristics, other exposures, and lifestyle/environmental variables. Continuous dose-response and step-function parameterizations of aspirin exposure were both statistically significant and not clearly distinguishable from each other. The estimated aspirin effect is significantly greater for girls than boys. Aspirin effects on offspring function were found in the absence of effects on physical size both at birth and at 4 years. Maternal acetaminophen use was not significantly related to child IQ or attention. As this exploratory research originated from observations of a data set gathered for other purposes, it would be desirable to have these findings replicated in other studies. Further follow-up of the children at a later age is planned.  相似文献   
82.
A study was made of the ultrastructure of cell nuclei of two types of hybrid clones obtained from the fusion of Chinese hamster with human skin fibroblasts, and from that of mouse hepatoma cells with mink fibroblasts. In cell nuclei of the eight hybrid clones deep invaginations of the inner membrane, not characteristic of the parent cells, were revealed. Analysis of serial sections, and application of electron microscopic radioautography and histochemistry have suggested that these structures are associated with the nuclear envelope which is necessary for regulating the superfluous chromosome localization in the hybrid nucleus.  相似文献   
83.
A study was made of the structural changes in different organoids of enterocytes of the rat small intestine at "rest" and during lipid absorption using ultrathin sections, impregnation with Ur-Pb-Cu, and continuous impregnation with OsO4. With the latter technique a specific canalicular system was found in the enterocytes, which we failed to observe on ultrathin sections. During lipid absorption the canalicular system underwent fragmentation. The vesicules on the trans-surface of the Golgi apparatus were enlarged, and the number of flattened cisterns was significantly lower. The changes in cellular organoids and their interrelations observed in the present study support the earlier hypothesis of the resynthesis of triglycerides within the enterocytes, the formation of chylomicrons and their transfer into the intercellular space.  相似文献   
84.
Studies have been made on the role of the thyroid in the development of rats. In the first group of experiments, newborn rat received within a month mercazolyl which inhibits the activity of the thyroid; in animals of the second group, mercazolyl injections were combined with cold exposures which stimulated motor activity in animals. It was found that hypothyroid rats in both groups exhibit retardation of growth as compared to normal animals. However, retardation is less significant in animals of the second group, as it is indicated by smaller changes in the protein content and total mass of skeletal muscles.  相似文献   
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M. Magnin  N. Pasteur  M. Raymond 《Genetica》1987,74(2):125-130
Strains of Culex pipiens derived from natural populations collected in southern France were crossed to determine their ability to give fertile offspring. Uni- and bi-directional incompatibilities occurred between these strains and each of them had its own crossing properties. Compatibility or incompatibility of a cross seemed to be related to the geographic distance separating the parental colonies, but not to their ecological origin (hypogeous or epigeous). Our results showed evidence for the variation in time of crossing properties of a strain.  相似文献   
88.
Summary The purpose of this paper is to describe the immunocytochemical localization of M protein of vesicular stomatitis virus (VSV) in infected cells. Vero cells, MDBK cells, Swiss 3T3 cells, and BHK cells were examined at various times after infection. For immunofluorescent staining, the cells were fixed with PLP fixative and then treated with 0.05% Triton X-100 before incubation with antibodies. Three hours after infection, M protein exhibited diffuse immunostaining throughout the cytoplasm and later accumulated along the cell membrane. The localization of M protein differed from the granular localization of the nucleocapsid N protein of VSV in the cytoplasm. For electron microscopy, the cells were fixed first in a mixture of 2% paraformaldehyde and 0.05% glutaraldehyde and then with PLP fixative, this being followed by treatment with 0.05% saponin. They were then immunostained using the immunoperoxidase method. The M protein was found to be distributed throughout the cytoplasm and later under the cell membrane, especially at virus budding sites. We also used postembedding immunostaining and freeze-fracture immunostaining to avoid the translocation of M protein caused by the detergent treatment. These techniques confirmed our previous results. Our findings are consistent with the view that the M protein of VSV is synthesized on free ribosomes and is then associated with the cell membrane where viral assembly may occur.S. Ohno was a visiting fellow from the Fogarty International Center at the National Institutes of Health, USA, from September 1981 to August 1983, while some parts of this work were in progress.  相似文献   
89.
Advanced approaches to the synthesis and reconstruction of genetic material developed in the Institutes of Molecular Biology and Genetics during the past years are summarized. The evolution of methods for oligonucleotide synthesis and scopes for their use in gene production are discussed. The principles of localised mutagenesis methods developed in the Institute are described, such as: a) mutagenesis directed to the regulatory gene regions; b) segment-localized mutagenesis; c) mutagenesis directed by phosphotriester analogues of oligonucleotides. Examples of employing these methods for induction of regulatory mutants of phage lambda, production of fused genes, mutant interferon genes, construction of new DNA vectors, construction of hybrid H1-H3 subtype haemagglutinine gene of influenza virus etc. are presented. The approach to in vivo site-directed mutagenesis is experimentally substantiated.  相似文献   
90.
The clastogenic and mutagenic activities of a new antifertility and antitumor agent gossypol were studied in the mouse male germ cells. Results of the present work indicate that at the doses 125 and 250 mg/kg the drug does not significantly increase frequencies of the micronuclei in the early spermatids and sperm head abnormalities. Hence, genotoxic influence can not be proposed as responsible for the antifertility effect of gossypol.  相似文献   
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