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B Velimirovic

Publications and source records attributed to B Velimirovic.

At least 19 recordsLinked to original sources
PubMed1996

Inward rectification of the IRK1 K+ channel reconstituted in lipid bilayers.

Inwardly rectifying potassium (K+) channels (IRK1) were incorporated into lipid bilayers to test the relative contributions of various mechanisms to inward rectification. IRK1 channels were expressed in Xenopus laevis oocytes and oocyte membrane vesicles containing the channels were fused with lipid bilayers. The major properties of the IRK1 channel were similar whether measured in the oocyte membrane or lipid bilayer; the single channel conductance was 21 pS in 140 mM symmetrical [K+] and varied as a square root of external [K+]. Importantly, IRK1 channels display voltage-dependent inward rectification in the absence of divalent ions or charged regulators such as spermine, indicating that they possess an intrinsic rectification mechanism. Although rectification was significantly increased by either Mg2+ or spermine added to the cytoplasmic face of the channel, their effects could not be explained by simple block of the open pore. The Hille and Schwartz (1978) model, originally proposed to explain inward rectification by singly charged blocking particles, cannot be used to explain rectification by multiply charged blocking particles. As an alternative, we propose that in addition to a slow gating mechanism producing long lasting open and closed states, there is a distinct, intrinsic fast gating process amplified by cytoplasmic Mg2+ and/or polyamine binding to the channel.

Animals↗
PubMed1995

The cardiac inward rectifier K+ channel subunit, CIR, does not comprise the ATP-sensitive K+ channel, IKATP.

Cardiac IKACh is comprised of two inwardly rectifying K+ channel subunits, CIR and GIRK1 (Krapivinsky, G., Gordon, E. G., Wickman, K., Velimirovic, B., Krapivinsky, L., and Clapham, D. E. (1995) Nature 374, 135-141). A cardiac protein virtually identical to CIR, termed rcKATP-1 (Ashford, M. L. J., Bond, C. T., Blair, T. A., and Adelman, J. P. (1994) Nature 370, 456-459), was reported to form an ATP-sensitive inwardly rectifying K+ channel, IKATP. We attempted to determine whether CIR alone or together with an unknown protein(s) participated in the formation of cardiac IKATP. Expression of CIR in insect, oocyte, and mammalian cell systems did not increase the appearance of ATP-sensitive currents, but rather gave rise to unique strongly inwardly rectifying, G protein-regulated K+ currents. CIR protein is found exclusively in atria, in contrast to the predominance of IKATP functional activity in ventricle. Also, CIR was completely depleted from heart membrane after immunodepletion of GIRK1. We conclude that CIR/rcKATP-1 is not a subunit of cardiac IKATP and that GIRK1 is the only channel protein coassociating with CIR in heart.

ATP-Binding Cassette Transporters↗
PubMed1992

Infection and cancer: current state of art.

Empirical evidence of the association of cancer with parasitic and viral infectious agents has been recognized earlier. Today, viruses are thought to account for about 10% of all cancers and they take a central place in experimental cancer research. This area has expanded tremendously with modern molecular biology techniques, the knowledge of gene expression, cellular enzyme and mechanisms of transformation. However, the last proof of causality is not yet available. Serologic, virologic, experimental and protective evidence is needed to confirm the assumptions in this rapidly developing field of research. The prevention of hepato-cellular carcinoma by effective vaccines now available is, in the opinion of the WHO, at least theoretically possible.

Humans↗
PubMed1990

[Attitude of medical students to alternative healing methods].

In Austria, the interest in alternative healing is obviously increasing, particularly among aspiring physicians. Several separate surveys were carried out by the Institute of Social Medicine in Graz among established physicians, general practitioner trainees and students of the Medical Faculty in order to learn something about their attitudes to alternative therapies. The surveys were directed towards the acceptance or refusal and the utilization of main alternative practices. The attempts show the difficulties in obtaining valid information. Only two satisfied the stringent criteria for the evaluation. This showed that popularity of alternative medicine was pronounced with students. The interest could be explained in part by the insufficiencies in the quality of medical education and by the influence of biased mass media.

Attitude of Health Personnel↗
PubMed1989

[Alternative healing methods in Austria].

The term "alternative medicine" serves as collective name for all healing methods and medicines whose efficacy has not been confirmed by controlled studies and trials. The various methods are separated by a broad spectrum from the scientific opinions of official medicine. Some are close to conventional practice; they are tolerated or even partly integrated into the official healing system, which means that physicians are permitted to apply them. However, this tolerance of non-scientific methods has as consequence led to a weakening of the Austrian law. The official position with respect to the most widely used methods of alternative healing, as well as the aggressive trend towards a technology which supports alternative healing methods, are discussed.

Austria↗
PubMed1989

[Succession from the viewpoint of the primary physician, education of the general physician. Results of a representative survey of faculty of Steiermark].

A study of post-graduate training for physicians, as viewed by the department-chiefs, was carried out in 1989 by the Institute of Social Medicine of the University in Graz, Austria, and compared with the opinions of the trainees themselves, as found in a previous study. The comparison shows that various differences exist, but also agreements between the answers of both studies. Both groups strongly emphasize the need to improve the curriculum of the post-graduate training and the quality control of the performance of trainees, as presently the training does not guarantee a uniform standard. The department-chiefs consider the university training as insufficient in up to 30% in theoretical, and 85% in practical fields.

Attitude of Health Personnel↗
PubMed1989

[The inadequate status of information of interested lay persons about the educational campaign regarding risk factors for cardiovascular diseases].

181 interested individuals (75 males, 106 females; range 16 to 84 years) responded to a questionnaire issued by the Styrian Cardiovascular Lay Society. The main topic of the questionnaire concerned information gained via media, about the possible risk factors related to cardiovascular diseases and about any changes in life style consequent to this information. The results show that the general knowledge in this field especially in younger subjects is disappointing and that there is need for further intensive information and education.

Adolescent↗
PubMed1987

AIDS as a social phenomenon.

AIDS is an infectious but also a social disease. Next to the major epidemiological question on the natural history of AIDS, important problems have been posed in various fields of social, political, ethical and legal areas extending far beyond traditional medical interest. These create polarization among public, politicians, press and also among physicians. As the situation changes, the gravity of the disease has become more prominent and the consensus on the effectiveness of the means used and proposed is not yet achieved. Social phenomena depend on societal values, the perception of fear and menace of disease to individuals versus perception of the collectivity. Among major risk groups this fear influenced by various ideologies and societal goals, is more pronounced than the response of the society warrant. It is not one of condemnation but of tolerance, and sympathy and has been directed not toward deterring people in engaging in certain kinds of sexual behaviour, but toward doing this with minimum risk. Conflict between the perception of rights (individual versus collective) is bound to grow although it is easy to distinguish in law legitimate epidemiological needs and their possible misuse. The present position of the main risk groups is changing in various ways. The reluctance of society to address openly issues of sexual behaviour has disappeared. There is rapidly accumulating knowledge on the social influence in the spread of the disease, but as yet, scant information on the influence of social factors on the control efforts and effectiveness of preventive behavioural strategies. The effects AIDS will have on the complex social structures in general, on health structures in particular, and on the problems which might shape future attitudes, values and morals cannot be delineated with any degree of precision but only vaguely guessed as the disease progresses now and into the next century.

Acquired Immunodeficiency Syndrome↗