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Biomedical subjects

A M Volkov

Publications and source records attributed to A M Volkov.

At least 19 recordsLinked to original sources
PubMed2006

[Content of microelements in left ventricular myocardium of patients with ischemic heart disease. Data of roentgenofluorescent analysis with the use of synchrotron irradiation].

Contents of 11 microelements (Se, Rb, K, Sr, Ca, Cr, Mn, Fe, Cu, Ni, Zn) in various parts (zone of infarction, of scar, periinfaction zone) of left ventricular myocardium of patients with ischemic heart disease was studied with method of rentgenofluorescent analysis with the use of synchrotron irradiation (overall 2112 analyses). Left ventricular myocardium of victims of accidents without cardiovascular pathology was studied as control. Compared with control dysbalance of various degree was noted in left ventricular myocardium of patients with ischemic heart disease. Four groups of microelements were distinguished: lowered content (Se, Rb, K); close to normal content (Mn, Cu); moderately elevated content (Cr, Sr, Fe); elevated content (Ni, Zn). Several orders of magnitude elevation of Ni and Zn was noted in all parts of left ventricle, especially in the zone of infarction and periinfarction zone.

Female↗
PubMed2005

Ultrastructural analysis of secretory granules of myocardial capillary endothelium in cardiosurgical stress.

In patients with chronic myocardial tissue hypoxia irrespective of the disease (Fallot's tetralogy, coronary disease) factors of cardiosurgical stress initiate a drop of secretory production in coronary capillary endothelium and obstruction of the intravascular space by blood cells. In children the peak of exocytosis of secretory granules coincides with the period of aortic occlusion, while in adults it is attained at the stage of reperfusion.

Capillaries↗
PubMed2005

[Endothelium of myocardium microvessel under conditions of hypothermia, ischemia, reperfusion and pharmaco-cold cardioplegia with calcium antagonist].

Microvessels of the right atrium endothelium were investigated with electron microscope for patients with congenital heart disease receiving surgical treatment under deep perfusionless hypothermia and various methods of pharmaco-cold cardioplegia. In group 1, pharmaco-cold cardioplegia was performed, with hyperosmolar normopotash solution cooled down to 2-4 degrees C. In group 2, the same solution combined with isoptin, a potash-ion blocker, was applied. It has been shown that during global ischemia, stability of ion gradients on plasmalemma of endothelial cells is impaired, irrespective of the composition of cardioplegia solution. Alongside with this, ultrastructural reactions in group 1 proceed towards hyperosmia of endothelium accompanied by building up a large group of cells following coagulation necrosis. In group 2, by contrast, an intracellular edema progresses. The cardioprotective effect of isoptin, which is able to block Ca2+, manifests itself most vividly at reperfusion, when the blocking of cell potash overload prevents the development of dystrophic and destructive changes in endothelium of coronary microvessels, which present one of the most severe consequences in the process of blood flow recovery in ischemic tissues.

Calcium Channel Blockers↗
PubMed2003

[Intraoperative reservation of auto-blood in surgical treatment of ischemic heart disease].

The article presents results of using the method of intraoperative autotransfusion in surgical treatment of IHD. It was shown that in patients with IHD intraoperative reservation of 400 ml of autoblood at the stage of surgical access (prior to infusion of heparin) during coronary shunting did not lead to disturbances of hemodynamics, gas exchange and oxygen-transporting function of blood. The following transfusion of predonated autoblood at the final stage of operation promotes the early reestablishment of the circulating erythron and allows to reduce the requirement of transfusion of the donor erythrocyte concentrate by 26.1%, and chilled plasma--by more than 1.5 times.

Blood Loss, Surgical↗
PubMed2002

Changes in myocardial metabolism and ultrastructure of myocardial microvessels during pharmacological and cold cardioplegia under hypothermic conditions without perfusion.

A combination of pharmacological and cold cardioplegia in with hypothermia without perfusion in open-heart surgery guarantee the reversible character of shifts in energy and free radical balance in the myocardium. However, this procedure can impair coronary micricirculation due to structural and functional changes in microvessel endothelium. Our results demonstrate that new cytoprotective approaches are extremely needed for cardiac protection during surgery.

Cardiac Surgical Procedures↗
PubMed2002

[The role of specific endothelial granules in changes of myocardium microvessel reperfusion at open-heart operations under hypothermia].

For patients with congenital heart defects, a comparative analysis was carried out of specific endothelial granules and morphological properties of perfusion capacity of microvessels at various stages of reperfusion after prolonged circulatory arrest. At all stages of reperfusion, the quantity of specific granules in microvessel endothelium dramatically dropped, as compared with the control group. At the early stages of reperfusion, the level of granule exocytosis does not lead to any statistically significant changes in perfusion characteristics in the right atrium microvessels, as compared with the control group. Conversely, at the late stages of reperfusion, degranulation of endothelial cells is enhanced, and physiological mechanisms intended to remove the microvessels from circulation are replaced with pathological ones. These results suggest the existence of a threshold in exocytosis of specific endothelial granules, whose exceeding may switch on some pathological mechanisms in blood flow regulation.

Cell Degranulation↗
PubMed2002

[Intravascular photohemotherapy in the complex prophylaxis of purulent-septic complications after coronary shunting].

The article presents results of treatment of 78 patients with the history of coronary bypass operations for ischemic heart disease. There were 48 patients with high risk factors of the development of pyo-septic complications. Among them there were 27 patients treated by complex postoperative therapy including intravascular photomodification of blood. The intravascular irradiation of blood was shown to have a positive influence upon the development of the early postoperative period in this category of patients. The immunomodulating effect was noted due to a greater amount of activated lymphocytes and T-helpers in blood. The positive dynamics of immunological indices were in correspondence with the data of the clinical state, pyo-inflammatory complications were not registered in this group of patients. Early (on the 3rd-5th days) inclusion of the intravascular irradiation of blood in the complex postoperative therapy is thought to be expedient for the patients with high risk of pyo-inflammatory complications.

Adult↗
PubMed2001

Effect of calcium antagonists on ultrastructure of myocardial microvessels during open heart surgery under conditions of pharmacological and cold cardioplegia.

Ultrastructure of myocardial microvessels was examined during surgical correction of congenital heart disease (ventricular septal defect) under conditions of cold and pharmacological low-potassium cardioplegia without perfusion. Addition of calcium antagonist verapamil to cardioplegic solution prevented postischemic damage to vascular and perivascular structures occurring during reperfusion and body temperature rise.

Body Temperature↗
PubMed1999

Experimental studies on the endothelium ultrastructure of heart capillaries under moderate (28-30 degrees) and deep (22-24 degrees) hypothermia without perfusion.

Ultrastructural changes in endothelial cells (EC) of myocardial capillaries were studied in 24 dogs which underwent hypothermia without perfusion. Biopsy specimens for electron microscopy were taken from the left ventricle of each dog in the control group, during anesthesia (prior to active cooling), and at the end of moderate (28-30 degrees ) and deep (22-24 degrees ) artificial body cooling. The following morphological types of the EC were identified both in the control group and in all test groups: those with moderately dense cytoplasm, light, dark, and irreversibly damaged cells. Dark cells showed increased numbers of plasmalemmal vesicles and appeared to be more transport-specialized as opposed to other types. In all stages of the experiment the amount of dark cells continuously increased (to 23.80, 34.62, and 47.17%, respectively). On cooling to 28-30 degrees, subcellular manifestation of reduced synthetic activity of organelles (nucleus, Golgi complex, and rough endoplasmic reticulum) was observed in all types of the EC. These changes persisted, or even increased, at the end of deep hypothermia. The transport activity of the EC changed differently in three experimental groups in all cell types. Micropinocytotic activity increased under spontaneous mild hypothermia (34-35 degrees ) during anesthesia and tended to decrease with subsequent artificial lowering of the temperature to 22-24 degrees. These ultrastructural changes seem to make up an integral part of the process of capillary endothelium adaptation to body surface cooling, and they might contribute to the development of tolerance to subsequent ischemic exposure during cardiac arrest.

Animals↗
PubMed1997

[The comparative morphology of the specific endothelial granules in the microvessels of the hypertrophied myocardium in patients with congenital heart defects and in experimental animals].

Specific endothelial granules of myocardial microvessels were studied in both patients, suffering from different congenital heart pathology, and dogs, before and during hyperthermia. In the intact myocardium of dogs we found two morphological varieties of granules, dark and light ones. The ultrastructural polymorphism of these granules was due presumably to hyperthermia. In cases of heart disease, a third morphological form of granules was revealed in the endothelium of myocardium microvessels in the hemodynamic overloaded heart compartments. These granules were larger and had a lighter matrix and a lesser amount of tubes. The granules are considered to be ultrastructural characters of structural reconstruction in the wall of hypertrophied myocardium microvessels at the endothelial level.

Animals↗
PubMed1996

[The ultrastructural characteristics of specific endothelial granules in the myocardial microvessels in congenital heart defects].

Specific granules in endothelium of microvessels of the right atrium were studied in 15 patients with congenital heart diseases (Fallot tetrad, defect of interventricular septum and aortal stenosis) aged from 3 to 11 by electron microscopy 2 morphological types of granules, varying in optic density-dark and light ones, were found in all observations. Great number of the light granules young forms was also discovered. Maturity of the latter is associated with the increase of number and density of localisation of tubular structures in the granule matrix. Share of granule-containing endotheliocytes varied significantly depending on the kind of the defect (from 27% in aortal stenosis up to 44% in Fallot tetrad), with number of granules varying from 1 to 37 in profile 1. This demonstrates that granule-producing function of endotheliocytes in congenital heart diseases depends on the load exerted on the region, compensating the disturbed hemodynamics in specific pathology and either on presence or absence of hypoxemia.

Aortic Valve Stenosis↗
PubMed1995

[The ultrastructural characteristics of the capillary endothelium from different sections of the canine heart].

Electron microscopy of auricular and ventricular endothelial blood capillary cells (EC) was performed for two groups of dogs, both at normal body temperature (control) and after cooling up to 28-30 degrees C. Cell organelles involved in synthetic processes were developed more in the auricular EC, and the number of specific granules in these exceeded that in organelles of the ventricular EC. The ventricular transport structures were more numerous and more diverse compared to the auricular ones. These subcellular features retained under hypometabolism induced by cooling. Both common (reduction of organelles involved in synthesis) and different ultrastructural responses to cooling were observed in auricular and ventricular endothelial cells. It is established that under hypothermia the ratio between "dark" and "light" granules in auricular EC remains invariable. At the same time, in ventricular EC the share of "light" granules in this ratio was 4 times more than in the control group. These results suggest an existence of ultrastructural differentiation of auricular and ventricular EC.

Animals↗