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排序方式: 共有96条查询结果,搜索用时 15 毫秒
1.
Malate- and isocytratedehydrogenase activity in mitochondrial and cytoplasmic fractions and lactate dehydrogenase activity in hindlimb muscles have been studied at different stages after 18.5-day flight on a biosatellite "Cosmos-1129" and after 20-day hypokinesia. A decrease in dehydrogenase activity has been found on the first postflight day. The enzyme activities returned to the control values in mitochondria, and in the cytoplasm they were greater by day 6 postflight. It was concluded that hypokinesia did not reveal all the effects of microgravity on the whole system but some enzyme alterations in the muscle resembled those observed during the flight. The effects may be caused by the inhibition of both aerobic and anaerobic metabolic pathways under the effect of microgravity. 相似文献
2.
We have isolated the delta-globin gene of the New-World spider monkey,
Ateles geoffroyi, and compared its nucleotide sequence with those of other
primate delta- and beta-globin genes. Among primate delta-globin genes, the
rate of nonsynonymous substitutions is much less than the rate of
synonymous substitutions. This suggests that primate delta- globin genes
may remain under evolutionary conservation, perhaps because hemoglobin A2
has an as yet unknown physiological importance.
相似文献
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Bone marrow stroma contains mesenchymal stem cells (MSC) which are progenitor cells, at least for tissues arising from mesechyma. The study of MSC biology yields controversial data. Therefore further experiments are needed to characterize these cells. The aim of our research was to compare primary cultures and subcultures of stromal precursor cells isolated from rat bone marrow. Long-term cultures of these cells isolated from 5 animals have been obtained. Morphological, immunophenotypic, and functional (capacity to osteogenic differentiation) characteristics of the cells have been investigated. We show that the cell morphology in the cultures is highly heterogenic. Morphological cell types are described. Heterogeneity of stromal cells declines on late passages. Cell cultures isolated from different animals have the same immunophenotypic markers (CD90, CD44, CD54, CD106, CD45, CD11b) but different morphological characteristics and a different capacity to osteogenic differentiation during long-term cultivation. The data show that more specific markers and functional tests should be applied to identify MSC. 相似文献
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Merzlikina NV Buravkova LB Romanov YA 《Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology》2004,11(2):P193-P194
Mesenchymal stem cells (MSCs) are specific cells capable of long-term proliferation and differentiation into various stromal tissue cell types. The state of MSCs depends on the cellular microenvironment and several soluble factors. We proposed that gravity could, in addition, influence MSCs features. To prove this hypothesis, we studied the effects of prolonged clinorotation on cultured human MSC morphology, proliferation rate and expression of specific cellular markers. Human bone marrow-derived MSCs were isolated by Histopaque-1.077 density centrifugation and cultured in DMEM-LG with 10% FBS. MSC cultures were composed of fibroblastoid cells negative for hemopoietic cell markers and positive for ASMA, collagen-1, fibronectin, CD54, CD105 and CD106. Cells were exposed to clinorotation from 1 hour to 10 days. It was shown that the proliferative rate was decreased in experimental cultures as compared to cells growing in normal conditions. Clinorotated MSCs appeared more flattened and reached confluence at a lower cell density. The obtained results suggest that cultured human mesenchymal stem cells sense the changes in gravity vector and may respond to microgravity by altered functional activity. 相似文献
7.
Romanov YA Buravkova LB Rikova MP Antropova EN Savchenko NN Kabaeva NV 《Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology》2001,8(1):P5-P8
Using histochemical staining and FACS-analysis we have studied the basal and TNF-alpha induced expression of E-selectin, ICAM-1 and VCAM-1 in human umbilical vein endothelial cells (ECs) exposed to simulated hypogravity. Control ECs did not contain detectable amounts of E-selectin or VCAM-1 but were ICAM-1 positive. As soon as after 6-8 hrs of clinorotation at 5 RPM the cellular content of ICAM- 1 increased. Moreover, hypogravity potentiated the effect of inflammatory cytokines (TNF-alpha and IL-1) on ICAM-1 expression. No increase in E-selectin or VCAM-1 expression was observed in ECs exposed to hypogravity itself. However, hypogravity reduced E-selectin and VCAM-1 expression in cell cultures activated by cytokines, more visible at their low (5-10 U/ml) concentrations. Both, control and clinorotated ECs poorly supported spontaneous lymphocyte adhesion; the adhesion of PMA-activated leukocytes was 15-20-fold higher. The interaction of unstimulated lymphocytes with cytokine-activated endothelium was more noticeable but significantly lower in cultures exposed to hypogravity. Activated blood cells interacted with endothelium more effectively, particularly, under hypogravity. Obtained results suggest that EC adhesion molecule expression and endothelium-lymphocyte interaction are altered under simulated hypogravity conditions in direction of increase of endotlielial adhesiveness for activated blood cells. 相似文献
8.
Gal'chuk SV Turovetskiĭ VB Buravkova LB Rubin AB 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2003,89(3):329-338
Microfluorimetry of single cells could help to analyze their morphology and function state during changes of gas environment. It is very important to have a possibility of the cell visual control during hypoxia and collection of dynamic fluorimetric data in digital form. The effects of short-term pO2 decrease were studied. For estimating the effects of hypoxia and reoxygenation we used the mice peritoneal macrophages, which are very sensitive to physical, chemical and regulatory stimuli. A special small chamber for fluorimetric measurements during pO2 changes, was developed. The level of active oxygen forms, intracellular pH, and cell membrane instability were investigated during replacement of air by nitrogen or argon (of the basal level decreased to 20% of basic level) and in subsequent reoxygenation. The increase of active oxygen forms was shown during 30 min of hypoxia and their level continued to rise immediately after reoxygenation. A short-term decrease and subsequent increase of pO2 in the medium led to an increase of intracellular pH level. The shifts of measured cell indices were stabilized after 30-40 min of pO2 changes thus suggesting a fast comprehension of countermeasure cell mechanisms. No macrophages with membrane disorders were found despite the rise of the active oxygen forms level during hypoxia and reoxygenation in vitro. There were no significant differences between nitrogen and argon used for replacement of air in the medium. The data obtained suggest a high resistance of macrophages against pO2 changes and an involvement of the antioxidative mechanisms for cell protection especially during reoxygenation period. 相似文献
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Giselle?L?Ferrari Jefferson?LB?Marques Rajiv?A?Gandhi Simon?R?Heller Fábio?K?Schneider Solomon?Tesfaye Humberto?R?GambaEmail author 《Biomedical engineering online》2010,9(1):26