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Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections 总被引:15,自引:4,他引:11
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A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules. 相似文献
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An effect of stable magnetic field on karyotype and cell division of human lymphocytes from peripheral blood was studied in tissue culture. Comparative investigations were carried out with lymphocytes, whoch were treated with magnetic field of different tension (0,179; 0,391 and 0,600 Ts) and continuance (30 sec, 30 and 60 min). Lymphocytes, treated with stable magnetic field, were suspended in donor plasma and immediately cultivated after the treatment. The stable magnetic field was found to have a distinct mutagenic effect on cultivated lymphocytes of human peripheral blood. The increase in structural impairements of chromosomes correlated with tension of magnetic field and continuance of its effect. In structural impairements of chromosomes the chromatid gaps and breaks were more often observed but chromosome ruptures and pericentric clearances occurred more rarely. The effect of stable magnetic field on lymphocytes proliferation was studie. Under weak and transient using of magnetic field the proliferation was stimulated, but in rigid conditions--mitosis and blastic transformation were decreased. Continuous effect of magnetic field with weak tension did not inhibite the blastic transformation but influenced on the survival rate of cells in tissue culture, enhancing their lethality. 相似文献
5.
AV Shevchenko IG Budzanivska TP Shevchenko VP Polischuk D Spaar 《Archives Of Phytopathology And Plant Protection》2013,46(2):139-146
The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants. 相似文献
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Nine original nitinol self-smoothing-out stents and 3 Gianturco stents were implanted to treat benign strictures of biliary ducts and biliodigestive anastomosis after ineffective repeated attempts to make balloon dilatation. There were no complications associated with the implantation procedure. The follow-up of patients varied from 3 to 26 months. After 4 months, reobturation was revealed at the site of repair in one case, which required implantation of an additional stent coated with polytetrafluoroethylene. The patency of the biliary tract was preserved in the remaining patients in the above period. 相似文献
7.
Parametric analysis of the ratio-dependent predator–prey model 总被引:3,自引:0,他引:3
We present a complete parametric analysis of stability properties and dynamic regimes of an ODE model in which the functional response is a function of the ratio of prey and predator abundances. We show the existence of eight qualitatively different types of system behaviors realized for various parameter values. In particular, there exist areas of coexistence (which may be steady or oscillating), areas in which both populations become extinct, and areas of "conditional coexistence" depending on the initial values. One of the main mathematical features of ratio-dependent models, distinguishing this class from other predator-prey models, is that the Origin is a complicated equilibrium point, whose characteristics crucially determine the main properties of the model. This is the first demonstration of this phenomenon in an ecological model. The model is investigated with methods of the qualitative theory of ODEs and the theory of bifurcations. The biological relevance of the mathematical results is discussed both regarding conservation issues (for which coexistence is desired) and biological control (for which extinction is desired). 相似文献
8.
Sysoev Yu. I. Prikhodko V. A. Idiyatullin R. D. Chernyakov R. T. Karev V. E. Okovityi S. V. 《Journal of Evolutionary Biochemistry and Physiology》2022,58(1):292-301
Journal of Evolutionary Biochemistry and Physiology - Electrocorticogram registration and analysis (electrocorticography, ECoG) is widely used in small-animal biomedical research. To date, a... 相似文献
9.
Artem S Novozhilov Faina S Berezovskaya Eugene V Koonin Georgy P Karev 《Biology direct》2006,1(1):6-18
Background
Oncolytic viruses that specifically target tumor cells are promising anti-cancer therapeutic agents. The interaction between an oncolytic virus and tumor cells is amenable to mathematical modeling using adaptations of techniques employed previously for modeling other types of virus-cell interaction. 相似文献10.
Georgy P Karev Yuri I Wolf Andrey Y Rzhetsky Faina S Berezovskaya Eugene V Koonin 《BMC evolutionary biology》2002,2(1):18-26