Radiation Induced Enhancement of Hydrogen Influence on Luminescent Properties of nc-Si/SiO Structures.

Using photo-luminescence, infrared spectroscopy, and electron spin resonance technique, the silicon dioxide films with embedded silicon nanocrystals (nc-Si/SiO structures) have been investigated after γ-irradiation with the dose 2 × 10 rad and subsequent annealing at 450 °C in hydrogen ambient. For the first time, it was shown that such a radiation-thermal treatment results in significant increase of the luminescence intensity, in a red shift of the photoluminescence spectra, and in disappearance of the electron-spin resonance signal related to silicon broken bonds. This effect has been explained by passivation of silicon broken bonds at the nc-Si-SiO interface with hydrogen and by generation of new luminescence centers, these centers being created at elevated temperatures due to transformation of radiation-induced defects.

[Metabolic disturbances as a factor of the pathogenesis of hypertensive disease and its clinical outcomes].

Aim: To identify and determine the mechanisms of an association between arterial hypertension (AH) and proatherogenic systemic metabolic disturbances in hypertensive disease (HD), as well as the possibility of eliminating these disturbances by antihypertensivetherapy.

Subjects And Methods: Fifty-four patients with HD and 64 persons randomly selected from an unorganized urban population were examined. Systolic and diastolic blood pressure (BP), insulin sensitivity, the most important metabolic parameters of lipids, lipoproteins, and glucose, the degree of systemic inflammation and oxidative stress, and the rate of lipoprotein proatherogenic and immunogenic modification were determined.

[Hypertrygliceridemia as a factor of atherogenesis: significance and mechanisms of action].

The aim of the study was to investigate the pattern of lipid and lipoprotein metabolism disturbances in patients with manifested clinical signs of coronary atherosclerosis. There was determined the significance of hypertrigliceridemia as the marker of these disturbances and its connection with other most important factors of atherogenesis such as insulin resistance, systemic inflammation, and oxidative stress, blood lipoprotein modification. The role of excessive alimentary lipid consumption as a factor, which initiates the hypertrigliceridemia development and accompanying activation of the other proatherogenic factors was determined with the use of acute lipid loading.

[Surgical treatment of Meckel diverticulum complicated by an acute hemorrhage].

Mekkel's diverticulum (MD)--is the inborn anomaly, caused by incomplete yolk duct development, it is present in near 2% of population and in 95% of observations lacks clinical manifestations. Symptoms of the disease manifest while complications occurrence only--in presence of peptic ulcer with possible hemorrhage and perforation occurrence, while ileus, diverticulitis, hernia, umbilicus fistula and tumor development. Eight patients, suffering MD, complicated by gastrointestinal hemorrhage, were treated during 1983-2006 yrs in Kyiv's city center for giving the aid to patients suffering gastrointestinal hemorrhage (GIH).

[The presence and characteristics of interrelations between lipid metabolism disorder and systemic inflammation].

The aim of the investigation was to determine the existence and describe interconnection between the lipid metabolism disturbances and development of systemic inflammation. The work was carried out on rabbits in two series of experiments: in the first one, the model of inflammation was reproduced by means of intravenous injection of bacterial lipopolysaccharide. In the second one, the model of lipid disturbances induced by lipids enriched diet was reproduced.

[Hyperlipidemia and decrease of lipid tolerance as factors of atherogenesis].

In experiments performed on rabbits the influence of acute and chronic alimentary lipid loading on the pathogenic factors of atherosclerosis was examined. A single moderate lipid loading even in normal rabbits was established to induce a transitory development of the proatherogenic changes, which includes appearance of dislipidemia of diabetic type, activation of systemic inflammation and free radical reactions, blood lipoprotein modification. Prolonged keeping of rabbits on the diet enriched with lipids induced the development of complex changes which are typical for insulin resistance with specific lipid and lipoprotein metabolism disturbances, increased plasma atherogenic potential, activation of systemic inflammation and oxidative stress.

[Modified lipoproteins--their types and role in atherogenesis].

In the performed clinical and experimental investigation there were determined the significance of lipoprotein modification in atherogenesis and the mechanisms of blood atherogenicity development. The pronounced changes of total blood cholesterol and the spectrum of lipoproteins in patients with coronary atherosclerosis were not regular and were noted only in 40-55% cases. The most regular was the increasing of blood atherogenicity, reflecting the appearance of the great amount of modified lipoproteins.

[The role of a systemic inflammatory process in the atherogenic modification of lipoproteins and the development of hypercholesterolemia].

The aim of the investigation was the determination of the systemic inflammatory process significance as a casual factor of the atherogenic blood lipoprotein (LP) modification and hypercholesterolemia (HCE) development. The availability of the HCE and atherogenic LP in blood of the patients with chronic coronary disease was established to coincide with the distinct sighs of the inflammatory process such as monocytes activation and oxidative stress development. Under the primary character of the inflammation--in children with acute respiratory infectious diseases and in conditions of experimental rendering of acute inflammation in rabbits by the intravenous injection of latex microspheres or pyrogenal there was also determined the distinct dependence between monocytes activation, increasing in blood free radical processes intensity, LP atherogenic modification and HCE development.

[The pathophysiological basis of the destabilization of the clinical course in ischemic heart disease].

The role of the coagulative blood system in initiation of acute coronary events was investigated on patients with different clinical forms of ischemic heart disease (IHD). The obtained results indicate that unstable angina (UA) and myocardial infarction (MI) are two independent forms of the acute IHD with distinct qualitative peculiarities. The most common feature of UA was an increase in the functional activity of platelets both in cases proceeded in MI and in uncomplicated cases.

[Role of hypercholesterolemia in the pathogenesis of atherosclerosis].

The pathogenic role of hypercholesterolemia in the development of atherosclerosis was determined by investigation of the vessel's wall structural and functional peculiarities in rabbits, which were kept on atherogenic diet. It was evident, that even short duration of hypercholesterolemia led to significant disturbances of vascular reactivity, which manifested mainly in the inhibition of endothelial vasomotor activity against a background of the initial increase of smooth muscle sensitivity to contracting influences. These changes were almost the same in quality and magnitude in all the investigated sections of the vascular system including venous.

[Activation of free-radical processes as a factor of ionizing radiation-induced changes in contractile activity of a vascular wall].

The influence of ionizing irradiation (1, 2 and 4 Gy 137Cs) on both the activity of free-radical processes in plasma, formed elements and aorta wall as well as on the character of contractile vascular reactions of isolated rings of thoracic aorta and carotid artery in rabbits has been studied. The experiments were carried out on the 7th day after the whole-body irradiation. The results indicate that simultaneously with the weakening of antioxidant mechanisms both endothelium-dependent and endothelium-independent vascular wall relaxation slightly decreases after 1 Gy exposure.

[The vascular protective effect of the combined administration of magnesium chloride and antioxidants in prolonged hypercholesterolemia ].

The angioprotective efficacy of combined application of magnesium chloride and antioxidants during prolonged hypercholesterolemia has been investigated on the experimental model of atherosclerosis in rabbits. The application of magnesium chloride and acetate tocopherol from the very beginning of the atherogenic diet is shown to exert a pronounced angioprotective effect preventing the development of structural and functional changes in the aorta wall. If the treatment is initiated against the background of the well developed atherosclerotic symptoms, its efficacy is less pronounced but remains still on a quite high level.

[Acute gastrointestinal hemorrhages].

It was thought formerly that gastrointestinal hemorrhage is an integral part of gastric ulcer. At present this is not a regularity, occurs only in some patients with ulcer disease and in other kinds of pathology (liver cirrhosis, dilated esophageal veins and oth.).

[Character and mechanisms of changes in vascular wall reactivity in prolonged hypercholesterolemia].

Changes in the structure and functional properties of the vascular wall after 8 months of alimentary hypercholesterolemia (HCE) were studied. The experiments were conducted on the circular bands of the arch of the aorta in rabbits. Sharp inhibition of the reactivity of the vascular bands was established, which was associated first of all with thickening of the intima due to the development of fibro-atheromatous changes in it.

[Efficacy of vascular wall protection from atherosclerotic damage using various calcium antagonists].

The authors studied the effect of various calcium antagonists--verapamil (VP) and Mg2+ (MgCl2) on the character of affection of the vascular wall ulcer conditions of prolonged hypercholesterolemia (HCE). The blood cholesterol (CS) content increased by the end of the 8th month of HCE to eight-fold the value in intact animals. The specific atherosclerotic changes in this case occupied approximately 80% of the area of the thoracic aorta whose functional properties changed essentially.

[Functional state and adrenergic reactivity of the myocardium in experimental atherosclerosis].

The authors studied the changes in the functional properties of a rabbit heart in protracted alimentary hypercholesterolemia (HCE). It is shown that HCE has a little effect on the characteristics of myocardial contractility and adrenergic sensitivity. In protracted HCE the probability of the occurrence of a myocardial own rhythm in response to the effect of isoprenaline increased.