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51.
52.
E. A. Arifulin E. E. Bragina V. A. Zamyatnina E. G. Volkova E. V. Sheval’ S. A. Golyshev L. N. Kintsurashvili G. I. Kir’yanov A. N. Prusov V. Yu. Polyakov 《Russian Journal of Developmental Biology》2012,43(2):121-130
Changes in chromatin structure at different stages of differentiation of human spermatids were studied. It was shown that,
in nuclei of early spermatids, chromatin is loosely packed and its structural element is an 8-nm fiber. This “elementary”
fiber is predominant at the initial stages of differentiation; in the course of maturation, it is replaced by globular elements
approximately 60 nm in diameter. In intermediate spermatids, these globules start to condense into fibrillar aggregates and
reduce their diameter to 30–40 nm. At all stages of spermatid maturation, except the final stages, these globules are convergence
centers for elementary fibers. This remodelling process is vectored and directed from the apical (acrosomal) to the basal
pole of the nucleus. In mature spermatids, the elementary 8-nm fibers are almost absent and the major components are 40-nm
fibrillar aggregates. The nuclei of mature spermatids are structurally identical with the nuclei of spermatozoa with the so-called
“immature chromatin,” which are commonly found in a low proportion in sperm samples from healthy donors and may prevail over
the normal cells in spermiogenetic disorders. The cause of this differentiation blockade remains unknown. Possibly, the formation
of intermolecular bonds between protamines, which are required for the final stages of chromatin condensation, is blocked
in a part of spermatids. The results of this study are discussed in comparison with the known models of nucleoprotamine chromatin
organization in human spermatozoa. 相似文献
53.
T. O. Volkova I. E. Malysheva N. N. Nemova 《Russian Journal of Developmental Biology》2005,36(1):14-20
We studied the ability of phorbol 12-myristate 13-acetat to prevent erythroid differentiation and apoptosis in erythroleukemic K562 cells induced by cytidine, thymidine, and guanosine. The exposure of cancer cells to combinations of phorbol 12-myrsitate 13-acetate (100 nM) nucleosides for two days led to a loss of hemoglobin production (marker of erythroid differentiation) in cells and increased expression of monocyte-macrophage lineage associated surface antigen CD14. The treatment of K562 cells with nucleosides only was accompanied by the activation of caspase-3 and caspase-9, rather than caspase-6, increased fluorescence of ethidium bromide and DAPI upon binding to DNA, and apoptosis. Intracellular activation of caspase-6, inhibition of caspase-9, a markedly decreased activity of caspase-3 and of fluorescence of DNA-binding dyes, and inhibition of apoptosis were observed when the cells were treated with phorbol 12-myeristet 13-acetate combined with nucleosides.Translated from Ontogenez, Vol. 36, No. 1, 2005, pp. 18–25.Original Russian Text Copyright © 2005 by Volkova, Malysheva, Nemova. 相似文献
54.
I/D polymorphism in the angiotensin-converting enzyme gene in men with myocardial infarction at young age] 总被引:1,自引:0,他引:1
O A Berkovich E A Bazhenova E A Volkova M Z Alugishvili I O Kiselev B I Smirnov E I Shvarts E V Shliakhto 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2001,87(5):642-648
The rate of D allele did not differ between patients with ischemic heart disease (IHD) who had myocardial infarction before the age 45, and healthy males. The DD genotype of the ACE gene was much more frequently encountered in the patients than in healthy males. The findings suggest that the DD genotype is an independent risk factor of the IHD and myocardial infarction in young patients. 相似文献
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56.
The investigation addresses the ecological role and the current ecological status of mountain mires in the Kuznetsk Alatau.
It inquires into the geo- and hydrochemistry of peat deposits, along with mire and river water, which comprise a typical mountain-mire
ecosystem, Krestovskie Mires. The chemical composition of summer rainwater collected in Kuznetsk Alatau Nature Reserve and
at its periphery has also been considered. The study area is located on Kuznetsk Alatau Nature Reserve, near Mt. Chemodan. 相似文献
57.
Metabolic processes in the uterus damaged in different parts of its innervation were studied. The specificity of neurodystrophic processes in the uterus depends on the nature of the injury to its innervation. Combination of different methods of modern morphological analysis made it possible to reveal hypoplastic processes in all the layers of the uterus. 相似文献
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59.
Entomological Review - A new genus, Wittinia gen. n., is proposed for Megalopygidae moths restricted to the Western Hemisphere. Two species are included: Wittinia cremor sp. n., the type species... 相似文献
60.