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Biomedical subjects

V A Golovko

Publications and source records attributed to V A Golovko.

12 recordsLinked to original sources
PubMed2003

[Single "early" action potential cause by Ni2+ ions in true pacemaker cells of the sinoatrial ring of the dace heart].

Single "early" action potentials (AP) or "early" postdepolarization (EAD) were recorded in multicellular stripes working in the regimen of true pacemaker cells located in the basis of the sinoatrial valve of the dace (Leuciscus rutilus) heart after Ni2+ (0.3 mM) were added to superfused solution on the 15 th min. The standard microelectrode technique was used. The appearance of single EAD was preceded by increase of AP spike duration almost 1.5-fold due to increase of the duration of a final repolarization phase and of diastolic depolarization. EADs appeared at different levels of repolarization from -20 to -60 mV. EAD's amplitude was lower than the AP proper. The effect is reversible. Nifedipine (2 microM) decreased by 20% the AP duration to 50% repolarization in the cells of atrial type. In case the stripes were primarily subjected to nifedipine effect and then even after a long procedure of washout, the Ni2+ (0.3 mM) did not cause EADs. The hypothesis has been tested of what is the main reason of single EAD appearance in pacemaker cells under the effect of Ni2+; it is either blocking Ca release from the cell by Ni2+, or reactivation of L-type Ca-channels' conductivity. The analysis of the data obtained leads to the conclusion that 30-50% Na-Ca-exchangers block is the basic reason of single EAD appearance in pacemaker cells.

Action Potentials↗
PubMed2003

Single and multiple early afterdepolarization caused by nickel in rat atrial muscle.

We examined the possible role of the Na-Ca exchange (NCX) in the arrhythmogenesis in rat atrial preparations applying microelectrode technique. In control Tyrode solution preparations isolated from the sinoatrial area contracted with frequency of 48+/-4 min(-1) (group I) or 84+/-7 min(-1) (group II). In preparation beating with low frequency partial inhibition of NCX by administration of Ni2+ (0.3 mmol/l) to the bath solution caused single early afterdepolarization (EAD) on the 15th min. During the following five minutes they were transformed into multiple EADs from 4 to 47 (action potentials) with general duration of 1-12 s. The effects were reversible. Ni2+ (0.3 mmol/l) in the preparations beating with higher rate (group II) did not cause multiple EADs, but after higher Ni2+ concentration (0.5 mmol/l) single EAD was observed more often. It was concluded that Ca2+ overload due to partial block of the NCX can contribute to the development of atrial tachyarrhythmias.

Action Potentials↗
PubMed1992

[Iridodiagnosis in the system of the follow-up of the health status of the population living in an area contaminated by radioactive substances].

The authors substantiate the practical employment of the iridodiagnosis screening-test using a system of archiving and visualization of the iris at the first stage of prophylactic medical examination and management. The economical and medical efficacy of the method has been established. Use of iridodiagnosis improved the detectability of pathologic conditions as compared with complex medical examination. Many specialists were freed from mass medical screening. The expenses for prophylactic medical examination became ten times less.

Adult↗
PubMed1992

[The dispensary observation of patients with chronic nonspecific lung diseases who work in a dust-producing industry with a high radionuclide level as a consequence of the accident at the Chernobyl Atomic Electric Power Station].

Patients working at a small mining institution and suffering of chronic unspecific pulmonary diseases due to high dust and radionuclide contamination levels were examined. Four groups of dispensarization were singled out with the purpose of differential treatment for each group. Such treatment including also antiaggregant agents, nitro-drugs resulted in a good medico-social effect within 2 years.

Accidents↗
PubMed1986

Modelling of the effects of Na+ and Ca2+ ions on the generation of action potentials by rabbit heart true pacemaker cells.

A comparison of results of modelling and physiological experiments allowed to estimate in the first approximation the quantitative contribution of calcium and sodium ions to the generation of different ionic currents determining the shape of the action potential (AP). Generally, the model reproduced adequately variations in AP shape with changes in the external concentrations of Na+ and Ca2+. At the same time the model differs slightly from the experimental results. To improve the model kinetic variables of slow inward current have to be taken into account.

Action Potentials↗
PubMed1986

[Effects of sodium and calcium ions on the potentials of cardiac pacemaker cells in the frog].

True and latent pacemaker cells were differentiated in the frog heart sino-atrial area. Within the first 5 min in the hyposodium solution, a decrease of the overshoot and maximal velocity of depolarization occurred. The true pacemaker cells did not reveal any changes of the AP parameters within 30-60 min. The cells of true pacemaker exhibited a higher sensitivity to the hypocalcium solution. The data obtained suggested a scheme of the whole cycle of Na+, K+ and Ca2+ exchange.

Action Potentials↗