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Biomedical subjects

I A Mikhaĭlova

Publications and source records attributed to I A Mikhaĭlova.

At least 19 recordsLinked to original sources
PubMed2002

[The effect of He-Ne laser radiation on myocardium mechanical activity in rats].

In isolated papillary muscles, a 5-minute irradiation with the He-Ne-laser Shuttle-1 enhances the maximal strength of isometric contraction and acceleration of relaxation. In physiological mode of mechanical loads, the irradiation with the laser red light enhances the myocardium contractability at all final systolic lengths with simultaneous enhancement of the isometric relaxation velocity at great systolic lengths and a deceleration of the relaxation at lesser lengths. Under the He-Ne-laser effect, restoration of rhythm-inotropic relationships occurred in the myocardium.

Animals↗
PubMed2001

[Effect of He-Ne laser irradiation on the functional activity of smooth muscle cells in the portal vein].

Irradiation of the rat portal vein's fragments with the He-Ne laser for 3, 5 and 10 minutes reduced the fragments tone by half. Frequency of phasic and tonic contractions did not change, their amplitude, however, increased by neatly 40% as compared with the initial level. The NO synthase blocker N-nitro-L-arginine administered prior to the irradiation had no effect on the above parameters. The data obtained suggest that the decrease of the vessel tone is due to production of the EDRF and cGMP. The increase in the amplitude of phasic and tonic contractions of the vein's smooth muscle cells is associated with an increased Ca++ entry in each contraction cycle.

Animals↗
PubMed1999

[Platelet adhesion to collagen in whole blood: a simple and rapid quantitative method].

A simple, rapid, and easily reproducible method for quantitative assessment and graphic representation of platelet adhesion of whole blood specimens is proposed. It is based on registration (by means of impedance aggregometer) of changes in the module of complex resistance of an EDTA-stabilized blood specimen by collagen. The amplitude of the process initiated under such conditions directly depends on collagen concentration, weakly decreases if blood is incubated with high concentrations of acetylsalicylic acid (500 micromol/liter), and significantly decreases in the presence of RGD-containing peptides in a concentration of 20-40 micromol/liter). A relatively higher collagen adhesion capacity of blood platelets from coronary patients correlates with their high aggregation activity.

Collagen↗
PubMed1995

[Polymyalgia rheumatica].

A case is reported of rheumatic polymyalgia rarely amenable to correct diagnosis. The response was achieved after glucocorticoid treatment. The diagnosis was based on the following criteria: age over 50, muscular pain (in two or more regions of the neck, shoulder and pelvic girdle, ESR above 35 mm/h, duration of the symptoms at least 2 months, limited movements in the cervical spine, shoulder and hip joints, weakness, subnormal appetite, fever, anemia, loss of weight.

Acute Disease↗
PubMed1995

[The thrombogenic properties and thromboresistance of the vessels in amphibians and reptiles].

Rats, frogs and snakes significantly differed in their thrombogenic activity and thromboresistance of microcirculatory vessels. Mammals revealed a higher thrombogenic activity and a more significant difference between arterioles and venules. Changes of hemodynamic parameters in arterial and venous parts occurring in the course of evolution seem to involve differences in vascular tone as well as in thromboresistance and thrombogenic activity.

Amphibians↗
PubMed1993

[The effect of L-glutamic acid on the ADP-induced aggregation and Ca, Mg-ATpase activity of human thrombocytes].

In the study of L-glutaminic acid effects on human platelet functional activity it was established that 30-60-min treatment of platelet-rich plasma with glutamate in concentration 0.1-1.0 mM at 37 degrees C results in a marked platelet activation. The latter noticeably enhances ADP-induced aggregation persistent against antiaggregation adenosine concentrations. With increasing duration of the incubation a glutaminic acid minimal effective concentration lowers. Proaggregatory and anti-adenosine effects of L-glutaminic acid are inhibited by kainic acid. The experiments evidence that 30-min preincubation of platelet membranes with 1 mM L-glutaminic acid produces inhibition of cAMP-induced activation of Ca, Mg-ATPase returning the activity of the enzyme to baseline levels. No glutamate-related changes in calcium pump of platelets are reported.

Adenosine Diphosphate↗
PubMed1993

[The thrombocyte function of subjects with atherogenic hyperlipidemias during lovastatin treatment].

The effects of lovastatin on in vivo spontaneous and in vitro ADP-induced platelet aggregability were studied in the blood of 36 persons with primary hyperlipidemias (HLP) of Types IIIa and IIb. In addition to decreases in blood cholesterol levels by an average of 33% and the atherogenicity coefficient to the normal levels, there was an increase in spontaneous and/or ADP-induced platelet aggregability in the first 2-3 months of lovastatin therapy. Lovastatin-induced in anti- and proaggregatory potential in the platelet-vascular wall system towards of the latter and spontaneous intravascular platelet formation suggest that there is a higher risk for thromboembolic events in the examined patients with Type II HLP, especially if they have coronary heart disease, during early stages of the drug administration. Therefore, there are reasons for recommending that lovastatin should be given under the control of the platelet hemostatic system.

Adenosine Diphosphate↗
PubMed1992

[Alterations in the functional activity of platelets in patients with angina pectoris during the cold test].

The functional activity of platelets was examined in patients with coronary heart disease and healthy individuals during cold test (CT). Patients prone to vasospastic responses to CT exhibited platelet activation along with beta-thromboglobulin release and formation of spontaneous platelet aggregates. Comparison of functional changes in platelet functional activity which occurred during cold test and intravenous ergometrine test suggest that the response to CT may be substantially higher if platelet aggregability is concurrently determined. The unidirectional changes in platelet aggregability during cold and ergometrine tests in patients with signs of dynamic coronary occlusion may indicate a relation of platelets with coronary vasoconstriction.

Adult↗
PubMed1991

[The link between the parameters of the thrombus formation process and blood flow velocity in the microvessels of the rat mesentery].

The role of shear rate in the processes of thrombocytes adhesion and aggregation was studied in vivo and in vitro. Certain parameters were obtained describing the thrombo-formation process in the rat mesenteric venules in different blood flow velocities. The experimental model took into consideration the dependence of the thrombocytes activation period on the distance from lesioned portion of vessel's endothelium.

Animals↗
PubMed1990

[Various indicators of vascular-thrombocytic hemostasis and blood rheology in ergometrine tests].

The function of platelets and erythrocytes and content of Willebrand's factor in the plasma from 45 patients with exercise-induced or spontaneous angina pectoris were examined before and after ergometrine, 0.1 mg. The patients with a negative ergometrine response showed a lower platelet sensitivity to all the aggregation inductors used in vitro, spontaneous platelet aggregation being absent. The function of erythrocytes and plasma levels of Willebrand's factor remained unchanged. The patients with a significant ischemic response to ergometrine exhibited platelet activation attended by the release of granule contents and formation of blood circulating platelet microaggregates. Concurrently, there was a decrease in erythrocyte deformability, as well as spontaneous blood red cell aggregation, the plasma levels of Willebrand's factor were increased 1.5-2-fold.

Aged↗
PubMed1988

[The sites of high affinity binding of L-[3H]glutamic acid in human platelets. A new type of platelet receptor?].

The total membrane fraction of human platelets was found to contain high affinity sites of L-[3H]glutamic acid binding (Kd = 100 nM, Bmax = 1.06 pmol/mg protein). The pH optimum for binding is at pH approximately 6.9 Na+ (1-150 mM) inhibit glutamate binding by platelet membranes (IC50 = 12 mM). Ca2+ (50-100 microM) stimulate the binding by 10-20% and inhibit it by 20-30% at concentrations of 1-5 mM. Monoclonal antibodies to the glutamate receptor strongly suppress the L-[3H]glutamate binding by platelet membranes (IC50 = 300 nm). The presence in human platelets of a glutamate-sensitive receptor complex similar to the central nervous system glutamate receptor is postulated.

Binding, Competitive↗
PubMed1988

[Serotonin metabolism in thrombocytes and microvascular hemostasis in spontaneous arterial hypertension].

Serotonin content and accumulation in platelets and its release from them, as well as changes in thrombus formation in mesenteric arterioles and venules of the small intestine have been investigated in control rats and rats with spontaneous hypertension (SHR). Serotonin accumulation in platelets was determined upon its incubation with platelets. Disodium ADP salt was used as an inductor of release. Laser-induced thrombosis was caused by microvessels exposure to impulse laser irradiation. The control animals revealed a significant difference between the initial serotonin platelet level and serotonin level upon incubation and release; in values, the values of basic thrombus-forming parameters were higher than in arterioles. In SHR there is a decrease in biogenic amine content in platelets, a depression in its accumulation and release, an increase in the time of thrombus growth, its size up to the separation of the first embolus and its length along the vascular wall. It is concluded that spontaneous hypertension is characterized by decreased functional activity of platelets and depressed resistance of arterioles and venules to thrombus formation.

Animals↗
PubMed1987

[Characteristics of thrombus formation in arterioles and venules].

The model of laser-induced thrombosis revealed a greater thromboresistance in arterioles rather than in venules of the rat small intestine mesentery, which accounts for a less frequent thrombosis and a lesser size of thrombus along the blood flow direction, whereas their greater thrombogenic potential accounts for a faster growth of thrombus and a shorter time of the primary hemostasis.

Animals↗