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排序方式: 共有488条查询结果,搜索用时 93 毫秒
41.
A. R. Kotovskaya M. I. Koloteva V. Yu. Luk’yanuk G. P. Stepanova L. M. Filatova S. P. Builov A. F. Zhernavkov L. L. Kondratuk 《Human physiology》2010,36(7):871-876
Analysis of alterations in the cardiac activity on the basis of electrocardiographic (ECG) findings in 29 cosmonauts of flight
and ground professions aged from 29 to 61 years after 34 short (8–30 days) space flights (SFs) between 1982 and 2006 has been
carried out. The ECG data at the stage of clinical selection, clinical-physiological examination (CPE) before a SF, at the
stage of the launch of a spacecraft (SC) into orbit and its landing on Earth and at the stage of postflight CPE have been
analyzed. The analysis of cardiac activity parameters on the basis of ECG data at different stages of observations has led
to the identification of three groups of cosmonauts. There were no significant changes or negative tendencies in the alteration
of ECG data in the first group (55.2% of the total number of cosmonauts) during the observation period from selection to the
end of the SF. The changes that later became more pronounced during the landing on Earth and were retained during postflight
CPE have been found in the second group of cosmonauts (in 34.5% cases) at the time of selection and preflight CPE. Considerable
disturbances in cardiac activity that are dangerous for human health have been found in ECGs in the third group (10.3%) during
the descent from orbit. The data from the study are the first step in the investigation of possible medical risks for the
development and improvement of requirements for the medical selection of crews and the admission of subjects with partial
health insufficiency on SFs. 相似文献
42.
43.
The electron-microscopic examinations of lymphocytes and neutrophiles in circulating blood of children irradiated during intrauterine development and on posterior stages of ontogenesis were performed in dynamics after accidental period. Some changes in lymphocyte ultrastructure were revealed; namely the increased undulation of nuclear contours with dilated perinuclear space and some reconstructions of their cellular organoids (the increased density of mitochondrial matrix, crist disorganization, dilation of clear space in cisterns of cytoplasmic net, disorders in the structure of electron-dense granules). The peculiarities of neutrophile ultrastructure that are characterized by centre dilated perinuclear space, decrease in glycosomes, disorders in granular structure, vacuole presence, degradation of cytoplasm and nuclear hypersegmentation were determined. 相似文献
44.
Processes of fluid exchange in the crystalline lens of the rabbit eye were investigated. The direction of movement of fluid in the crystalline lens was investigated from the movement of fluorescein by the method of "stopped diffusion". It has been found that the mechanism of fluid transport in the crystalline lens is active and is carried out by means of the Na-kappa-ATPase transport system. The energy necessary for the active transport of fluid inside the crystalline lens is in the range (1.5-6) x 10(-2) J. Owing to the active fluid transport, the pressure inside the crystalline lens constantly increases by 6 mm Hg. In rabbit's life-time, the movement of fluid in the crystalline lens occurs in the direction from the anterior to the posterior surface followed by the exit to vitreous humor. 相似文献
45.
46.
Vasil'ev SA Stepanova EIu Kutenkov OP Belenko AA Zharkova LP Bol'shakov MA Lebedev IN Rostov VV 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2012,52(1):31-38
Effects of ionizing radiation registered in cells after low dose irradiation are still poorly understood. A pulsed mode of irradiation is even more problematic in terms of predicting the radiation-induced response in cells. Thus, the aim of this paper was to study and analyze the effects of dose and frequency of pulsed X-rays on the frequency of radiation-induced DNA double-strand breaks and their repair kinetics in human peripheral blood lymphocytes in vitro. Analysis of radiation-induced gammaH2AX and 53BP1 repair foci was used to assess the DNA damage in these cells. The dose-response curve of radiation-induced foci of both proteins has shown deviations from linearity to a higher effect in the 12-32 mGy dose range and a lower effect at 72 mGy. The dose-response curve was linear at doses higher than 100 mGy. The number of radiation-induced gammaH2AX and 53BP1 foci depended on the frequency of X-ray pulses: the highest effect was registered at 13 pulses per second. Moreover, slower repair kinetics was observed for those foci induced by very low doses with a nonlinear dose-response relationship. 相似文献
47.
Kapustin A Stepanova V Aniol N Cines DB Poliakov A Yarovoi S Lebedeva T Wait R Ryzhakov G Parfyonova Y Gursky Y Yanagisawa H Minashkin M Beabealashvilli R Vorotnikov A Bobik A Tkachuk V 《The Biochemical journal》2012,443(2):491-503
uPA (urokinase-type plasminogen activator) stimulates cell migration through multiple pathways, including formation of plasmin and extracellular metalloproteinases, and binding to the uPAR (uPA receptor; also known as CD87), integrins and LRP1 (low-density lipoprotein receptor-related protein 1) which activate intracellular signalling pathways. In the present paper we report that uPA-mediated cell migration requires an interaction with fibulin-5. uPA stimulates migration of wild-type MEFs (mouse embryonic fibroblasts) (Fbln5+/+ MEFs), but has no effect on fibulin-5-deficient (Fbln5-/-) MEFs. Migration of MEFs in response to uPA requires an interaction of fibulin-5 with integrins, as MEFs expressing a mutant fibulin-5 incapable of binding integrins (Fbln(RGE/RGE) MEFs) do not migrate in response to uPA. Moreover, a blocking anti-(human β1-integrin) antibody inhibited the migration of PASMCs (pulmonary arterial smooth muscle cells) in response to uPA. Binding of uPA to fibulin-5 generates plasmin, which excises the integrin-binding N-terminal cbEGF (Ca2+-binding epidermal growth factor)-like domain, leading to loss of β1-integrin binding. We suggest that uPA promotes cell migration by binding to fibulin-5, initiating its cleavage by plasmin, which leads to its dissociation from β1-integrin and thereby unblocks the capacity of integrin to facilitate cell motility. 相似文献
48.
49.
N. M. Mineeva A. S. Litvinov I. E. Stepanova M. Yu. Kochetkova 《Inland Water Biology》2008,1(1):64-72
On the basis of the data obtained during field observations in the summer low water period of 2001, the patterns of chlorophyll
distribution and its relation to hydrological and hydrochemical factors in two eutrophic reservoirs of the Middle Volga are
studied. The hydrological structure of the Gorky Reservoir, where the Volga water mass dominates, is homogeneous, while in
the Cheboksary Reservoir along with the eutrophic Volga waters, the mesotrophic Oka water masses can be distinguished keeping
their abiotic and biotic features over a long distance. Phytoplankton in the two contiguous reservoirs with different flow
regimens and anthropogenic loads responds differently to the external influence. An autotrophic community in the Gorky Reservoir
is more stable and depends little on abiotic factors which account for ∼63% of the explained chlorophyll variation. In the
Cheboksary Reservoir under maximal for the Volga cascade flow velocity and anthropogenic load, the development and distribution
of phytoplankton are almost completely (R
2 = 0.93) controlled by these factors. The trophic state of the reservoirs has not changed as compared to the beginning of
the 1990s. 相似文献
50.
I. V. Nikolaev L. N. Kolobkova E. O. Landesman E. V. Stepanova O. V. Koroleva 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2008,2(4):426-431
The antioxidant and peroxidase activities of mixed saliva have been investigated during test loads in control group and patients with caries and combination of caries with inflammatory periodontal diseases. Antioxidant activity of saliva was significantly decreased in the last two groups and so its was corrected by means of xidiphone. 相似文献