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Biomedical subjects

F Z Meerson

Publications and source records attributed to F Z Meerson.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Adaptation to periodic hypoxia restricts subdural hemorrhages in audiogenic epileptiform convulsions in rats].

A potent sound stimulation induces in Krushinskiĭ-Molodkina rats epileptiform seizures associated with increased blood levels of stressor hormones and subdural hemorrhages in the brain. Adaptation to periodic hypoxia carried out in a pressure chamber prolonged twofold the latent period of seizure development and blood hydrocortisone content after seizures. Such adaptation reduced the incidence of subdural hemorrhages and the mean size of these hemorrhages. Adaptation scheme used in our experiments is virtually the same as that clinically used at present in the management of patients with allergic diseases and neuroses.

Acoustic Stimulation↗
PubMed1993

[Adaptation to stress can enhance animal resistance to sublethal hypoxia to a greater extent than adaptation to hypoxia].

Wistar male rats were adapted to intermittent hypoxia in an altitude chamber (group 1) and to short-term immobilization stress (group 2). The animals of both series and control ones were exposed to severe hypoxic hypoxia in acute experiment: they were anesthetized and inhaled a gas mixture which contained 6% O2. In the first two hours of the experiment the death rate was 65% in control, 10% in adaptation to stress, and 29% in adaptation to hypoxia. Principal parameters of respiration, circulation, and basic-acid equilibrium were monitored during the experiment. They allowed us to establish that both the variants of adaptation increased the tissue oxygen consumption; furthermore, adaptation to hypoxia preserved a higher level of oxygen consumption than adaptation to stress. Despite this, in adaptation to stress the death rate was threefold higher than in adaptation to hypoxia. This result was explained by the accumulation of heat shock proteins in cells during adaptation to stress and the resultant development of a phenomenon of adaptive stabilization of structures (PhASS). In adaptation to hypoxia the PhASS did not develop.

Acute Disease↗
PubMed1993

[The nondrug treatment of hypertension patients by their adaptation to periodic hypoxia in a barochamber].

Patients with essential hypertension were exposed to periodic hypoxia in a pressure chamber. It is shown that adaptation to periodic hypoxia results in improvement of general condition of patients who exhibited a decline in blood pressure, minute blood volume, serum sodium concentrations as well as better microcirculation and tissue oxygen tension. Reduced concentrations of total serum cholesterol and atherogenic index were achieved in hypercholesterolemia patients. The changes obtained permitted reduction of hypotensive maintenance treatment. In view of positive results in hypertensive subjects, adaptation to periodic hypoxia in a pressure chamber is recommended for inclusion into combined regimens of hypertension therapy.

Adaptation, Physiological↗
PubMed1993

[The intensification of nitric oxide synthesis in the aortic wall in experimental myocardial infarct].

The effect of experimental myocardial infarction on endothelium-dependent relaxation of isolated rat aorta and generation of nitric oxide in the aortic wall was studied. Three hours following myocardial infarction, the endothelium-dependent relaxation induced with acetylcholine was increased to 61 +/- 2% as compared with 41 +/- 4% in control (r < 0.05). The nitric oxide generation (EPR-assay) was 2.5 times increased in the aortic wall of animals subjected to myocardial infarction as compared with the control. The activated generation of nitric oxide may be provoked by the reduced minute volume of the heart and concomitant transient hypovolemia.

Acetylcholine↗
PubMed1993

[The effect of adaptation to a course of stress-inducing electrostimulation on the reactivity of an isolated resistive artery].

Repeated stress adaptation made with a course of electrostimulation was found to result in changes in the responsiveness of the rat isolated tail artery taken from adapted animals. These changes appeared as decreased vasoconstrictive responses to norepinephrine and significantly higher endothelium-dependent vasodilation induced by acetylcholine and the beta-agonist isoproterenol. The regulatory shift occurred towards vasodilation of the resistive artery makes the studies of the impact of stress adaptation on blood pressures in hypertension promising.

Adaptation, Physiological↗
PubMed1993

[The effect of adaptation to repeated stresses on the recovery of cardiac function and creatine phosphate after total ischemia (a 31P-NMR study)].

Adaptation to stress was produced by eight immobilizations of rats for 1 hour every other day. The effects of 25-min ischemia and subsequent 50-min reperfusion on the heart contractile function and energy metabolism were studied. In the adapted rats, the velocities of contraction and relaxation as well as the developed pressure restored during reperfusion much faster than in the controls. The NMR-study showed that a drastic fall of creatine phosphate (CP) and ATP during ischemia was followed by a rapid CP restoration, a Pi drop and a slow ATP restoration during reperfusion. In the adapted animals, the CP restoration was twice as rapid as in the controls. It is obvious that in adaptation to stress the heart function and the system of CP resynthesis appear to be significantly more resistant to ischemia stroke and this is why they restore their activity faster than in the controls.

Adaptation, Physiological↗
PubMed1992

Differences in adaptive stabilization of structures in response to stress and hypoxia relate with the accumulation of hsp70 isoforms.

The phenomenon of adaptive stabilization of structures (PhASS) develops during adaptation of the organism to intermittent restraint stress. The PhASS manifests itself in a considerably increased resistance of the heart to a broad spectrum of harmful factors. In the present work, the content of hsp70 and their role in the development of PhASS during adaptation to intermittent restraint stress and to intermittent hypoxia were studied. In adaptation to restraint stress, five hsp70 isoforms with pI ranging from 5.7 to 6.3 were accumulated in the myocardium. The heart simultaneously became strikingly resistant to reperfusion paradox and heat shock. In adaptation to hypoxia, only two hsp70 isoforms with pI about 5.8 were accumulated. The resistance to reperfusion paradox was not increased and the resistance to heat shock was increased only moderately. These data suggest a role of different hsp70 isoforms in the mechanism of PhASS as well as adaptive protection of the heart.

Adaptation, Physiological↗
PubMed1992

[The anti-arrhythmic efficacy of sodium valproate].

The antiarrhythmic efficacy of the anticonvulsant sodium valproate was studied in 22 patients with ventricular premature contraction in the immediate (10-15 days) and late (2-5 months) periods of therapy. The prolong antiarrhythmic effect of the drug was observed in 66% of the patients in whom it was beneficial in the first days of therapy. The results obtained provide strong evidence for the efficacy of sodium valproate in patients with ventricular premature contraction occurring in the presence of neurocirculatory dystonia.

Adolescent↗
PubMed1992

[The clinico-hemodynamic effects of the activator of the GABA-ergic stress-limiting system sodium valproate (acediprol) and etatsizin in patients with cardiac arrhythmias].

Hemodynamic and antiarrhythmic effects of acediprol and ethacizine were examined in 51 patients with premature ventricular contraction concurrent with neurocirculatory dystonia and coronary heart disease. It was ascertained that acediprol exerted a positive inotropic action and ethacizine lowered myocardial contractility. Acediprol therapy prevents or attenuates the hypokinetic and arrhythmogenic effects of stimulated stress in patients with ischemic and non-ischemic arrhythmias. The preventive antiarrhythmic effect of acediprol is the most pronounced in patients with neurocirculatory dystonia. Ethacizine fails to improve hemodynamic supply of the stress test and enhances stress-related hypodynamia in some patients.

Anti-Arrhythmia Agents↗
PubMed1992

[Role of the inositol phosphate cycle in the cardioprotective effect of adaptation to intermittent hypoxia].

The impact of adaptation to intermittent hypoxia of different duration (for 20 and 40 days) on the inositol triphosphate-diacylglycerol (ITP-DAG) regulatory contour in the heart was investigated. For this, isolated heart alpha 1-adrenoreactivity to phenylephrine and phospholipase (PhL-C) activities were studied in cardiac plasma membranes. On day 20 of adaptation, the heart inotropic response to phenylephrine stimulation was somewhat reduced and the activity of Ca(2+)-dependent PhL-C did not differ from that in the controls within the range of Ca2+ physiological concentrations. Forty days after adaptation, both positive inotropic responses of the heart to phenylephrine and activity of Ca(2+)-dependent PhL-C were enhanced, i.e. activation of the ITP-DAG regulatory cascade occurred. Early studies have shown that a phenomenon of adaptive stabilization develops at this stage of adaptation. The phenomenon appears as a significant increase in heart resistance to thermal injury, toxic catecholamine levels, Ca2+ paradox and high Ca2+ concentrations. Thus, the revealed activation of the ITP-DAG regulatory contour was accompanied by the development of a phenomenon of adaptive structure stabilization (PhASS) in the hearts of adapted animals. The findings suggest that the ITP-DAG regulatory cascade plays an important role in the cardioprotective effect of adaptation to intermittent hypobaric hypoxia and in PhASS formation.

Adaptation, Physiological↗
PubMed1992

[The role of the liver macrophage system in decreasing the immune complex level of the blood during adaptation to periodic hypoxia].

It has been established that adaptation to intermittent hypoxia in altitude chamber considerably increases the capacity of hepatic macrophagal systems (MFS) to uptake Indian ink particles from the blood as well as immunoglobulin labelled with fluorescein isothiocyanate. There is simultaneous catabolism of labelled albumin in hepatic MFS. It has been suggested that the increased C3b-component of complement system in blood observed in adaptation to hypoxia plays a substantial role in the activation of hepatic MFS. The role of hepatic MFS activation in reducing the number of circulating immune complexes is emphasized as well as its role in therapeutic effect of adaptation in allergic diseases.

Adaptation, Physiological↗
PubMed1992

[Adaptation to periodic hypoxia decreases ethanol consumption and abstinence-related damages to the internal organs during withdrawal in chronically alcoholized animals].

Adaptation to intermittent hypoxia in a hypobaric altitude chamber reduced two-fold ethanol consumption in chronically alcoholized rats and limited or eliminated abstinence syndrome. The effect of the adaptation was evident from prevented development of abstinence analgesia, enhanced alcohol consumption following deprivation, abstinence activation of lipid peroxidation in the liver, and release of hepato-specific enzymes fructose monophosphate and gamma-glutamyl transpeptidase into blood. At the same time adaptation prevented the fall of cardiac fibrillation threshold and pronounced disturbance of ventricular contraction and relaxation. The problem is discussed of using adaptation to intermittent hypoxia in the treatment for those forms of alcoholism in which abstinence plays the key role.

Adaptation, Physiological↗
PubMed1992

[Reversal of withdrawal injuries of the heart and liver by adaptation to intermittent hypoxia when discontinuing ethanol in chronically alcoholized animals].

Adaptation to intermittent hypoxia in the hypobaric altitude chamber showed a two-fold decrease in ethanol consumption in chronically alcoholized rats and attenuated or arrested the withdrawal syndrome. The impact of adaptation to the withdrawal syndrome was that it prevented the development of withdrawal analgesia, higher alcohol consumption after its withdrawal, withdrawal hepatic activation of lipid oxidation products and blood release of the hepatic specific enzymes fructose monophosphataldolase and gamma-glutamyl transpeptidase. Concurrently, the adaptation prevented the withdrawal fall of the cardiac fibrillation threshold and marked disorders of ventricular contraction and relaxation. The paper discusses whether adaptation to intermittent hypoxia can be used in the management of the types of alcoholism in whose development the withdrawal plays the key role.

Adaptation, Physiological↗
PubMed1992

[Increase of calcium-dependent activity of phospholipase C in the myocardium in adaptation of animals to short-term stress effects].

The effect of adaptation of rats to repeated short-term stress exposures was studied on the density and the affinity of alpha 1-adrenoceptors in the heart and on the phospholipase C activity and sensitivity to changes in Ca2+ concentration. It was found that adaptation to stress was accompanied by a desensitization of alpha 1-adrenoceptors and also by an increase in Ca(2+)-dependence of phospholipase C activity in the heart. The role of increased activity of phospholipase C and activated inositol triphosphate-diacylglycerol regulatory cascade is discussed as regard to the previously revealed accumulation of heat shock proteins in the myocardium and to the adaptive protection of the heart.

Adaptation, Physiological↗
PubMed1992

[Comparative anti-arrhythmia effectiveness of activators of body stress-limiting systems in patients with arrhythmia].

The antiarrhythmic effects produced by activators of the body's stress-limiting systems were comparatively evaluated in patients with cardiac arrhythmias of ischemic and non-ischemic etiology. Acediprol, gidazepam, and befol were found to be beneficial in ventricular premature contraction when psychoemotional stress was simulated, as evidenced by 24-hour monitoring. The most pronounced protective therapeutical effect of the drugs was observed in patients with arrhythmias of extracoronary origin and in individuals with a marked arrhythmogenic effect of stress. Gidazepam was shown to suppress the provocative arrhythmogenic effect of the stress test.

Adult↗