Biomedical subjects

I Iu Gavrilov

Publications and source records attributed to I Iu Gavrilov.

9 recordsLinked to original sources

PubMed1994

[The functional characteristics of the thrombocytes in patients with hypertension and "silent" myocardial ischemia].

Functional platelet characteristics were studied in hypertensive subjects having episodes of silent myocardial ischemia. A total of 36 patients with essential hypertension (EH) stage II (WHO criteria, 1979) underwent echocardiography and 24-h ECG monitoring. Platelet aggregation induced by adenosine diphosphate was assessed by laser aggregation analyzer. It is demonstrated that platelet aggregation in EH patients with silent ischemia was increased 5-fold as compared to healthy subjects and 2-fold versus EH patients without ischemia. No significant differences existed between the two groups by such parameters as systolic or diastolic pressure and left ventricular myocardial mass. An involvement of elevated platelet aggregation can be suggested in the genesis of coronary insufficiency in EH associated with episodes of silent myocardial ischemia.

Analysis of Variance↗

PubMed1990

[Increase of calcium ion level in the cytoplasm of indo 1-loaded HeLa cells under the action of histamine].

The regulation of free cytoplasmic calcium in HeLa cells was studied using a fluorescent calcium indicator into 1. It is found that addition of histamine caused substantial increase in calcium level. In calcium-free medium the increase was much smaller, implicating both intra- and extracellular calcium as sources of observed Ca2(+)-rise. Protein kinase C activator, phorbol myristate acetate, completely blocked the effect of histamine. Agents causing rise in cellular cAMP level did not change the Ca2(+)-rise.

Calcium↗

PubMed1989

[A new highly sensitive method of analysis of thrombocyte aggregation].

The new method for studies of the platelet aggregation kinetics is based on the creation of a platelet stream through the optic canal and on an analysis of fluctuations in the intensity of the luminous flux that has passed through the sample. The relative dispersion of fluctuations in the intensity of the light passed through the sample is suggested as a parameter for the estimation of the platelet aggregation and for analysis of their aggregation kinetics. The method permits recording the platelet aggregation in citrate plasma, enriched for platelets, after exposure to the inductor in very low concentrations (0.05-0.15 microM ADP). Scanning electron microscopy has shown that aggregates are indeed formed in such cases, and they can be recorded from the increase of the relative dispersion in the fluctuations in the passed light intensity but cannot be recorded by Born's optic method.

Adenosine Diphosphate↗

PubMed1989

[Functional state of blood platelets in arterial hypertension and the changes in serotonin-containing cellular granules].

The study was undertaken to examine the status of the granular apparatus and platelet aggregability in 9 healthy donors and 18 patients with arterial hypertension (AH), including 14 with essential hypertension (EH) and 4 with symptomatic forms of AH. Among the patients, a group of 8 EH patients was singled out, who had, compared with normal, reduced relative volumes of electron dense platelet granules (from 17.9 +/- 2.0 to 5.3 +/- 0.6%). The group also showed lower platelet serotonin levels (from 67.3 +/- 5.3 to 17.6 +/- 3.7 ng per 10(8) cells; p less than 0.001) and a 2-fold decrease in the transport factor of acridine orange across the cytoplasmic and granular membranes as compared to normal. A positive correlation was established between the amounts of cellular serotonin and the relative volume of platelet granules (r = 0.850; p less than 0.001).

Adult↗

PubMed1989

[New methodical approach to the study of platelet aggregation in vitro].

A new approach to the investigation of the kinetics of platelet aggregation is described. The method is based on the analysis of light transmission fluctuations produced on the changes in the number of platelets in optical channel. The relative dispersion of the fluctuations of transmitted light intensity was used as a parameter to estimate the degree of platelet aggregation. Application of this method for the analysis of platelet aggregation permits to get new information about this process.

Adenosine Diphosphate↗

PubMed1988

[A decrease in the stimulated level of free intracellular calcium in thrombocytes during refractoriness].

The concentration of free intracellular calcium (Ca.f) was determined in ADP-stimulated platelets. Free calcium was measured by the multichannel method using fluorescent probe indo 1. In the presence of extracellular calcium, ADP induced a rapid reversible increase in Ca.f followed by reversible platelet aggregation. The second addition of ADP also induced increase in Ca.f and platelet aggregation, which were of lesser magnitude (platelet refractoriness). Without extracellular calcium, ADP also produced an increase in Ca.f. In this case the second addition of ADP also induced considerably less increase in Ca.f.

Adenosine Diphosphate↗

PubMed1987

[Quantitative evaluation of the uptake capacity of intact thrombocytes using fluorescent dyes].

A new approach to quantitative determination of fluorescent dye uptake by intact cells is suggested. Fluorescent amine acridine orange selectively accumulating in 5HT granules of platelets has been used. Fluorescence signal analysis allows the estimation of a relative granule volume and the ratios of acridine orange transfer over cytoplasmic and granule membranes. The following results were obtained in human and rabbit platelets: a relative granule size was 14 +/- 1 % and 29 +/- 2 % of the total cell volume, intra-granule to extra-granule dye concentration ratios were 2260 +/- 382 and 30000 +/- 5550, while intra-cytoplasm to extra-cytoplasm concentration ratios were 375 +/- 60 and 225 +/- 60, respectively.

Acridine Orange↗

PubMed1987

[Accumulation of acridine amino derivatives by electron-dense granules in thrombocytes].

The uptake and release of dense bodies' content were studied using fluorescent amines. Real-time measurements of fluorescence spectra by a device developed on the basis of a multichannel optical analyzer and computer technique of spectrum deconvolution made it possible to investigate the kinetics of monoamine uptake and release in intact cells.

Acridine Orange↗

PubMedDate not supplied

[Measurement of the concentration of free cytoplasmic calcium in the process of platelet aggregation using a fluorescent method].

A multiwavelength method for measuring free cytosolic calcium concentration is proposed. It is based on the registration of the fluorescent spectrum of calcium--sensitive probe indo-1 and deconvolution of the spectrum into components corresponding to free and bound forms of the probe. Calcium concentration is calculated as a product of calcium-probe dissociation constant by calcium-bound to free form concentration ratio. The obtained values are independent of variations in light-scattering properties of the medium and total dye concentration in the optical channel. It is shown that during ADP-induced platelet aggregation calcium concentration rises without measurable delay after the addition of the inducer and significantly decreases by the time the aggregation begins.

Adenosine Diphosphate↗