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排序方式: 共有92条查询结果,搜索用时 31 毫秒
31.
Marten Szibor Jochen Pöling Henning Warnecke Thomas Kubin Thomas Braun 《Cellular and molecular life sciences : CMLS》2014,71(10):1907-1916
Cardiomyocytes continuously generate the contractile force to circulate blood through the body. Imbalances in contractile performance or energy supply cause adaptive responses of the heart resulting in adverse rearrangement of regular structures, which in turn might lead to heart failure. At the cellular level, cardiomyocyte remodeling includes (1) restructuring of the contractile apparatus; (2) rearrangement of the cytoskeleton; and (3) changes in energy metabolism. Dedifferentiation represents a key feature of cardiomyocyte remodeling. It is characterized by reciprocal changes in the expression pattern of “mature” and “immature” cardiomyocyte-specific genes. Dedifferentiation may enable cardiomyocytes to cope with hypoxic stress by disassembly of the energy demanding contractile machinery and by reduction of the cellular energy demand. Dedifferentiation during myocardial repair might provide cardiomyocytes with additional plasticity, enabling survival under hypoxic conditions and increasing the propensity to enter the cell cycle. Although dedifferentiation of cardiomyocytes has been described during tissue regeneration in zebrafish and newts, little is known about corresponding mechanisms and regulatory circuits in mammals. The recent finding that the cytokine oncostatin M (OSM) is pivotal for cardiomyocyte dedifferentiation and exerts strong protective effects during myocardial infarction highlights the role of cytokines as potent stimulators of cardiac remodeling. Here, we summarize the current knowledge about transient dedifferentiation of cardiomyocytes in the context of myocardial remodeling, and propose a model for the role of OSM in this process. 相似文献
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A new procedure has been worked out to establish restriction maps. The method is fast, does not in general require labeled DNA and has been applied to map the linear palindromic rDNA of Physarum with the restriction enzyme Bst EII. 相似文献
34.
Summary Cultures ofPhysarum polycephalum incubated with caffeine or theophylline for over 100 min prior to mitosis exhibited mitotic delay proportional to the time of treatment before 100 min. Starved cultures exhibited mitotic delay at times of starvation longer than 180 min and slight stimulation from 100–180 min. Dibutyryl cAMP appeared to accelerate reconstruction of the nucleus following mitosis.Acknowledgments. The authors wish to express their appreciation to Dr. Volker Vogt and Dr. Richard Threlfall for helpful discussions, to Kathryn Behrens for able technical assistance and to the European Molecular Biology Organization for a short-term fellowship to J. R. T. during the course of this work. Supported by grant 3.501.75 of the Swiss National Science Foundation. 相似文献
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Zusammenfassung Die fettmobilisierende und hypoglykämische Aktivität in Hypophysenhomogenaten alloxandiabetischer Ratten ohne Insulinbehandlung ist nach achtwöchentlicher Diabetesdauer stark vermindert. 相似文献
37.
The regular periodic activity patterns of mammalian cold receptors have been quantitatively studied. Analysis of the timing of either single impulses or impulse groups demonstrated that the periodic receptor process is maintained independently of impulse generation and continues to operate under conditions when afferent impulses are not initiated. These results imply that the underlying conductances must be operational at threshold potentials related to impulse generation. In addition to temperature, the periodic process is considerably sensitive to calcium, which affects mainly the probability of impulse generation during each cycle. Reduction of external calcium and application of calcium entry blockers with relative selectivity for low-threshold calcium channels are similarly effective in modulating cold receptor activity. The data imply the existence of a low-threshold calcium conductance at the sensory terminal. 相似文献
38.
Genetically haploid spermatids are phenotypically diploid 总被引:18,自引:0,他引:18
Because chromosomal homologues segregate from one another during meiosis, spermatids are genetically different. Post-meiotic gene expression could lead to gametic differences, some of which might lead to preferential transmission of certain alleles over others. In both insects and mammals, however, all the cells derived from a single spermatogonial cell develop within a common syncytium formed as a result of incomplete cytokinesis at each of the mitotic and meiotic cell divisions. It has been proposed that the intercellular bridges connecting the cells, which are about 1 micron in diameter, permit the sharing of cytoplasmic constituents, thus ensuring the synchronous development of a clone of cells and gametic equivalence between haploid spermatids. By analysing the product of a transgene which is expressed exclusively in post-meiotic germ cells in hemizygous transgenic mice, we have shown that genetically distinct spermatids share the product of the transgene and hence can be phenotypically equivalent. 相似文献
39.
Zusammenfassung Intraperitoneale Verabreichung von Insulin führte bei Ratten, die täglich 2 h gefüttert wurden, im Vergleich mit ad libitum gefütterten Kontrolltieren, zu einer grösseren Herabsetzung des Blutzuckerspiegels, einer höheren Fett- und Glykogensynthese im Fettgewebe, jedoch zu einer verminderten Glykogensynthese im Zwerchfell. 相似文献
40.
A Rico D Deviller J P Braun V Burgat-Sacaze P Benard 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1979,288(19):1493-1497
Toxic effects of combustion products originating from plane cabin constituents are studied, in vivo, in Rats. The model associates an important combustion room, and an experience room containing eight revolving cages for Rats; these cages allow a remote control of the movements of the Rats which can be electrically stimulated and ejected. Such a device permits to study the incapacitance, i.e. the inability to move. For the combustion of a seat, without ventilation, incapacitation appears in 2 to 6 min. Biochemical screening demonstrates on increase of pCO2, carboxyhemoglobin and glycemia and a decrease of pO2. 相似文献