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排序方式: 共有638条查询结果,搜索用时 15 毫秒
1.
S Masumura M Hashimoto Y Hashimoto T Sato I Kihara Y Watanabe 《European journal of applied physiology and occupational physiology》1982,48(2):157-161
Activities of glycolytic enzymes in the aorta were investigated in female Wistar rats. There were two groups of rats; one served as the control (sedentary rats), while the other group was forced to run on a treadmill for 10 weeks. In the control animals, the activities of hexokinase, phosphofructokinase and aldolase were relatively lower than those of the other glycolytic enzymes (phosphoglucose isomerase, lactate dehydrogenase and pyruvate kinase). After exercise, the activity of phosphofructokinase increased by 15%, whereas the other enzymatic activities were much the same as in the controls. Within the limits of the experiments, the increased percentage of phosphofructokinase was statistically significant (p less than 0.05). Since phosphofructokinase is a putative rate limiting enzyme, this enzymatic activation may indicate that glycolytic activity in the rat aorta is enhanced during and after running exercise. 相似文献
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A proteolytic enzyme was purified from Xenopus embryos. The purification procedure consisted of fractionation of an extract of embryos with acetone, gel filtration of Sephadex G-75 and chromatography on carboxymethyl-cellulose and hydroxylapatite. The preparation of enzyme appeared to be homogeneous as judged by electrophoresis in polyacrylamide gels. This protease had a molecular mass of 43-44 kDa and was composed of two subunits with molecular masses of 30 kDa and 13 kDa. The optimal pH of the reaction catalysed by the protease was approximately 4.0. This proteolytic activity was inhibited by antipain, leupeptin and iodoacetic acid; it was not affected by phenylmethylsulfonyl fluoride and pepstatin; and it was enhanced by dithiothreitol. In the presence of RNA, the optimal pH was shifted from pH 4.0 to pH 4.5. The protease was activated by addition of total RNA from Xenopus embryos, by poly(rU) or poly(rG). In contrast, after addition of tRNA or poly(rC), no activation of the protease was observed. 相似文献
4.
A comparative study of three methods for intracellular loading of the calcium indicator aequorin in ferret papillary muscles 总被引:7,自引:0,他引:7
We compared the results of loading the bioluminescent Ca++ indicator aequorin by standard microinjection techniques to those obtained with two new chemical approaches to loading that utilize low concentrations of Ca++ chelator; i.e., 1) Immersion and 2) Macroinjection. After loading with the immersion and macroinjection methods, twitch tension returned to pre-load values indicating lack of damage to the muscles. The aequorin signals obtained with all three methods were similar and converted to similar quantitative values for [Ca++]i. Our data suggest that chemical loading (in particular macroinjection) may be preferable to microinjection, particularly in muscles with increased connective tissue content. 相似文献
5.
S Miyata T Shimazaki Y Okamoto N Motegi M Kitagawa H K Kihara 《The Journal of experimental zoology》1988,246(2):150-155
We have studied the role of proteases during the development of Xenopus laevis embryos with the aid of protease inhibitors. The activity of proteases was found to be only minimal in the unfertilized egg and during the initiation of development, but activity began to increase at the morula stage. When the activity of proteases was inhibited by antipain, an inhibitor of endopeptidase activity, RNA synthesis in the embryo was inhibited. To examine the relationship between the inhibitory effect of antipain on protease activity and its effect on RNA synthesis, antipain was reduced with NaBH4 to inactivate its protease inhibitory activity. The reduced antipain did not inhibit RNA synthesis in the embryo. Antipain effectively inhibited synthesis of both rRNA and poly(A)+RNA but not 4S RNA. We therefore suggest that protease activity plays an important role in the initiation and/or continuation of RNA synthesis. 相似文献
6.
Influence of stress on the maturity of T-cells 总被引:3,自引:0,他引:3
Stress is known to influence the immune function via an effect on the central nervous system. We previously presented data showing that stress alters the population of T-cell subsets in mice. The variations of T-cell subsets in the thymus, peripheral blood, and spleen in mice similarly stressed by immobilization or by unavoidable and opioid-dependent stress were measured by flow cytometry using the monoclonal antibodies anti-L3T4, anti-Lyt 1, anti-Lyt 2 and anti-Thy 1, 2. Immobilization stress was applied for three days and T-cell subsets were measured on the days 1, 2 and 3, as well as on day 7 after release from immobilization. Lyt 2-positive cells in the thymus were the most sensitive to stress, showing significant variations. The proportion of immature T-cells increased in the thymus, blood and spleen of the stressed mice. When diazepam or naloxone were administered 30 min before the initiation of stress, these variations tended to decrease. Thus, the ratio of T-cell subsets varied with the duration of immobilization stress. This appeared to be partly mediated by the opioid system and the central nervous system. 相似文献
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Dr. Nobuyuki Shirasawa Hirotaka Kihara Fujio Yoshimura 《Cell and tissue research》1985,240(2):315-321
Summary The fine structure of each type of anterior pituitary cell in the male goat was studied through the application of a superimposition technique in which adjacent thick sections were used to identify individual cells beforehand by light-microscopic immunohistochemistry. A cone of the pars intermedia protrudes into the pars anterior, being surrounded by the narrow pituitary cleft; the immunohistochemical appearances of the cells forming the cone resemble those of the pars anterior. Several follicles appear in the pars anterior. Ultrastructurally GH cells resemble prolactin cells. The secretory granules of both types are spherical; the diameter of the former is about 340 nm, whereas that of the latter is about 440 nm. ACTH cells are polygonal in shape with secretory granules, about 180 nm in diameter, scattered throughout the cytoplasm. TSH cells, which are spherical in shape, contain the smallest secretory granules, 150 nm in diameter. The highly electron-dense LH cells contain numerous secretory granules about 210 nm in diameter. Their nuclei are irregular with incisures. Thus, the anterior pituitary cells of the goat are ultrastructurally characteristic and species-specific. 相似文献
9.
In vitro characteristics of rat mesangial cells in comparison with aortic smooth muscle cells and dermal fibroblasts 总被引:2,自引:0,他引:2
E Yaoita T Kazama K Kawasaki S Miyazaki T Yamamoto I Kihara 《Virchows Archiv. B, Cell pathology including molecular pathology》1985,49(4):285-294
Rat glomerular mesangial cells were cultured and their antigens were compared with those of aortic vascular smooth muscle cells and dermal fibroblasts. Glomeruli, aortic, and dermal explants were cultured for 3 weeks and subcultured in the same conditions. These cultured cells were evaluated by indirect immunofluorescence studies using antibodies against Thy-1 antigen, desmin, and chicken gizzard actin. Most of mesangial cells were positive for Thy-1, desmin, and actin. On the other hand, fibroblasts were negative for desmin, and smooth muscle cells stained Thy-1 scarcely, and were negative for desmin. In the latter two cells, actin-positive fibrils were thinner and fainter than mesangial cells. These results indicated that mesangial cells could be distinguished in vitro from vascular smooth cells and fibroblasts by immunofluorescence microscopy. 相似文献