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Biomedical subjects

S Israel

Publications and source records attributed to S Israel.

At least 19 recordsLinked to original sources
PubMed1991

A bioluminescence assay for gene expression by continuously growing mammalian cells: application for detection of human immunodeficiency virus type 1 (HIV-1).

An in-situ assay for monitoring regulated gene expression in continuously growing mammalian cells is described. This technique can be used for the detection of the transactivator (Tat) protein in human immunodeficiency virus(HIV)-infected cells. Human kidney cells 293, harboring the luc gene, and fused to the HIV-1 long terminal repeat, were isolated and served as tester cells. Tat is supplied by transfection with a tat-carrying plasmid, or alternatively by addition of Tat-containing cell extracts, made from virus-infected or plasmid-transfected cells. Light emitted from the tester cells is recorded on film continuously, or by a photo sensor. Transactivation by HIV Tat results in a pronounced increase in light emission from the tester cells (up to 3000-fold). This assay, which detects HIV-specific gene products, may be used as a diagnostic tool for the detection of active HIV present in peripheral blood.

Animals↗
PubMed1990

[Effect of sports on the distribution of body fat].

The pathogenetic effectiveness of the risk factor overweight is essentially modified by the distribution of the fatty depot. The form of obesity, the primary obesity, which above all is to be found in men is connected with a relatively high risk for the appearance and progression of several chronic diseases which at present determine morbidity. An only two-hour sports activity per week has a great influence on the size and the distribution of the lipopexia. Sporting persons have less body fat than inactive ones. In particular in sporting males the deposition of fat in the abdominal region is much limited.

Adipose Tissue↗
PubMed1986

A computer simulation of nuclear magnetic resonance imaging.

A modular, user-friendly computer simulation of NMR imaging was created for the DEC VAX computer. This simulation is novel in that complex imaging phenomena, such as chemical shifts and flow, may be easily studied. Other features include spin warp and backprojection imaging, movie generation, and simulation of image contrast, composite pulse sequences, motion artifacts, aliasing, selective excitation, field inhomogeneity, noise and signal averaging. The simulation incorporates fast Fourier transform and graphics modules for processing and display of one- and two-dimensional images. Examples which illustrate features of the program are shown. The simulation is a useful tool for both the sophisticated and the beginning user of NMR imaging. It serves as a drawing board for studying MRI phenomena and a teaching program for demonstrating basic techniques.

Adipose Tissue↗
PubMed1986

Binding of human TNF-alpha to high-affinity cell surface receptors: effect of IFN.

Human tumor-necrosis factor (INF-alpha), induced by Sendai virus in peripheral blood mononuclear leukocytes (PBMC), was isolated using a monoclonal antibody to the protein and radioiodinated by the chloramine-T method. Effective labelling of the protein with little loss of bioactivity was obtained. The labelled protein was found to bind specifically to high affinity receptors present on cells of various cultured lines. The molecular nature of these receptors was examined using the bifunctional cross-linking reagents disuccinimidyl suberate (DSS) and dithiobis succinimidyl propionate (DSP). In SDS-PAGE, conjugates between TNF receptors and the labelled TNF of two sizes (about 75 and 92 kDa) were detected. 125I-labelled TNF was also used to examine variations in TNF receptor concentration, upon treatment of cells by interferon (IFN) or TNF, and any correlation of observed variations with the effect of IFN and TNF on responsiveness of cells to the cytotoxicity of TNF. The decreased vulnerability of cells to the cytotoxic effect of TNF, following treatment of cells by TNF itself, was not correlated with decreased availability of free receptors for the protein. However, an increase in responsiveness of cells to TNF following treatment by IFN was accompanied by some increase in binding of TNF to the receptors.

Cell Line↗
PubMed1985

[Striving for movement-induced adaptation--why?].

The skeletal muscle is the most massive organ of the body. Its function is in close interaction with all organs; its activity serves as essential physiological adaptogenic stimulus for the optimization of organ functions. On the basis of an insufficient motion-induced adaptation the spreading lack of motion restricts the efficacy and the stability of vegetatively regulated functions. Morphological and functional adaptive modifications caused by motion may very well be represented at the heart in form of a model. These are objectifiable at a functional, coronary circulatory and cellular level. It can reasonably be started from the fact that an adequate motor activity, which belongs to the biohistorical scheme of the human body, is able to further stability of health, functional capacity and well-being.

Adaptation, Physiological↗
PubMed1984

A new method for reconstitution of highly fusogenic Sendai virus envelopes.

A new way for reconstituting highly fusogenic Sendai virus envelopes is described. As opposed to previously described methods, in the present one the detergent (Triton X-100) is removed by direct addition of SM-2 Bio-beads to the detergent solubilized mixture of the viral phospholipids and glycoproteins, thus avoiding the long dialysis step. The vesicles obtained in the present work resemble, in their composition, size and features, envelopes of intact Sendai virus particles. The present method allows the enclosure of low and high molecular weight material within the reconstituted viral envelopes.

DNA, Viral↗
PubMed1983

A possible involvement of virus-associated protease in the fusion of Sendai virus envelopes with human erythrocytes.

A proteolytic activity is shown to be associated with relatively purified preparations of intact Sendai virus particles or with their reconstituted envelopes which are vesicles containing mainly the viral glycoproteins. Intact Sendai virus as well as reconstituted Sendai virus envelopes have been shown to be able to hydrolyze various protein molecules such as the human erythrocyte membrane polypeptide designated as band 3 and soluble polypeptides such as histone and insulin B-chain. The results of the present work raise the possibility that a direct correlation exists between the virus-associated proteolytic activity and the ability of the virions to lyse cells, to fuse with their membranes, and to promote cell-cell fusion. Inhibitors of proteolytic enzymes such as phenylmethylsulfonyl fluoride, tosyllysinechloromethylketone and tosylamidephenylethylchloromethylketone, or combinations thereof, inhibit the virus-associated proteolytic activity concomitantly with inhibition of its hemolytic and fusogenic activities. Electron microscopic studies showed that the various inhibitors did not affect the binding ability of the virus preparations. The possible involvement of a protease in the process of virus-membrane fusion is discussed.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1977

[Effect of training in sports on the cardiovascular system of children and adolescents].

In a review the specific reaction of the cardiovascular system of children and youth to actual athletic stress and on a staying power training is dealt with. The present knowledge is imperfect because the medicine had a cautious opinion of the maximum stress of the infantile heart till recent times, and children training systematically were exceptions. The examination of the cardiovascular system of training children is complicated as far as the effects of training are mostly equal in direction like growth, maturing, and development effects. But it is evident that the infantile circulation system is well adaptable to staying power results. During training a cardiac enlargement surpassing the growth rate is arising. Under the condition of rest the heart of the trained child is more subjected to vagal control with the appropriate functional consequences. By submaximum stress an economization of the function can be observed. During stress a stronger inotropia with increased stroke volume and better oxygen absorption is stated. The post-stress phase is characterized by an accelerated return of the deflected functions to the zero level. Furthermore statements are made about the specific ECG of sporting children, about the problems of sports at heart diseases, about acceleration and retardation as well as about the transformation of physiologic knowledge into methodical conceptions for training.

Adolescent↗
PubMed1975

[Primary prevention and non-linearity in cardiovascular adaptation].

The size of the healthy heart and its function stand in a significant reciprocity. An enlargement of the heart in the sense of the formation of the athletic heart is characterized by an optimation of the function. On the basis of a larger sample the functional behaviour of healthy hearts between a size of 600 and 1,380 ml was tested. The function of the heart is not linearly connected with the size of the heat in the whole breadth of adaptation. When a small adaptation level is present a larger functional change is to be attached to a defined change of the size of the heart than in a high adaptation level. The curve of functional indices reveals a parabolic form above the size of the heart. This situation is present in rest, in submaximal load, in the phase of final load and in the phase of after-load. On the basis of representative parameters of the cardiovascular function this fact is demonstrated. The adaptation optimum is found nearly in the middle of the possible phase of adaptation. The author deals with the importance which these findings have for the primary prevention of cardiovascular diseases.

Adaptation, Physiological↗