[Effect of dosed diet restriction on physiological remodeling and bioelectric properties of bone].

The effect of dosed diet restriction on the physiological remodeling and bioelectric properties of bone tissue was studied in 48 male Wistar rats 3- and 18-months of age. The rate of bone tissue apposition was studied by the dynamic histomorphometry method (intravital tetracycline labeling). Electric potentials on the periosteal surface of the freshly isolated femurs were recorded.

[The influence of hyperoxic gas mixture on the respiratory part of the lungs in rats].

The respiratory part of the lungs was investigated in rats of 3 and 12 months of age before and after the influence of normobaric hyperoxic gas mixture (40 % and 90 % oxygen). We found the reduction in middle diameter, depth, cross-sectional area, width of the entrance to alveolus and the total width of respiratory bronchioles, alveolar ducts and sacs after 28 daily hyperoxic sessions (60 mines each). We detected increasing the amount of collagen fibers, the alveolar wall thickness and oxyproline concentration in a lung after breathing the hyperoxic gas mixture.

[The effect of altered oxygen partial pressure on the resisitance to hypoxia and expression of oxygen-sensitive genes in Drosophila melanogaster].

As a result of resistance test to hypoxia of Drosophilas melanogaster of Oregon strain, we identified a high resistance (Group II) and low resistance (Group III) subpopulations of flies. Flies from groups II and III were incubated in a constant normobaric hypoxia (Po2=62-64 mm Hg) for 10 generations. A highly resistant group (Group IV) were exposed to a shortterm anoxia (Po,=1,5 mm Hg, 5 min) every generation.

[Determination of age-related liver stiffness changes in rats according to the ultrasonic shear wave elastography].

We examined by ultrasound shear wave elastography (SWE) changes of liver stiffness (LS) in three groups rats of different ages. LS measurement by SWE was performed on "Ultima PA" equipment ("Radmir", Kharkov, Ukraine) with a 10-5 MHz linear transducer. To assess the functional state of the liver at the same time we studied age-related biochemical and morphological differences in the liver.

[The influence of normobaric hypoxia on the morphofunctional changes of thyroid gland in young rats].

We investigated the influence of hypoxic gas mixture (the different modes) on the morphometric indexes of thyroid gland functional activity in 3-mounth rats. It was shown a decrease in the size of follicles of middle area and the colloid and an increase in the amount of thyrocytes in a follicle, resorption vacuoles and interfollicular epithelium after exposure to hypoxic gas mixture (10% oxygen). We also detected an increase in a follicle-colloid index and a decrease in the colloid accumulation index.

[The effects of oxygen partial pressure changes on the osteometric markers of the bone tissue in rats].

Our purpose was to investigate the oxygen partial pressure changes on the osteometric and biochemical markers of bone tissue in rats. It was shown that breathing of altered gas mixture did not change the mass, general length, sagittal diameter and density thigh-bones in 12-month Wistar male-rats. The dosed normobaric hypoxia increased the activity of alkaline phosphatase and decreased the activity of tartrate-resistant acid phosphatase.

[Dosed normobaric hypoxia as a non-medication approach of stimulation of physiological regeneration of liver parenchyma].

The investigation was devoted to studying the effects of different modes of dosed normobaric hypoxia on the changes in morphometric indexes of functional activity and physiological regeneration of liver parenchyma in young rats. It was shown, that in rats exposed to hypoxic gas mixture (10% O2), the amount of karyonucleus and binuclear hepatocytes, nucleocytoplasmic and nucleolar-nuclear correlation increased. The changes in these indexes appeared to be more intensive when dosed normobaric intermittent hypoxia was administered with alternation of deoxygenation and reoxygenation periods.

[Effect of normobaric hyperoxia on the markers of bone tissue metabolism].

We studied the influencing of normobaric hyperoxia one hour daily during 14 and 28 days on the bone metabolism for 3- and 12-monthly Wistar male-rats (n =80). It was shown, that breathed normobaric gas mixture with 90% O2 during 14 days significant reducing of C-terminal propeptides of type I collagen levels for 36%, an increasing piridinolin levels for 37% and concentration of C-terminal telopeptides of type I collagen for 8% in the blood serum. We found reliable decreasing the concentration ofpiridinolin levels for 27% in adult rats in the same conditions.

[Physiologic regeneration and functional activity of hepatocytes in normobaric hypoxia].

It was studied the effects of dosed normobaric hypoxia during 14 and 28 days on physiological regeneration and functional activity liver of parenhima fenomenas of adult rats. It was shown that after completion of experiment at rats increase sizes nucleus, the area of cytoplasm decrease, and also is increase the hepatocytes amount on tissue area unit. Concentration albumin increased after 14 days ofnormobaric hypoxia.

[The effect of dosed normobaric hypoxia on physiologic regeneration of the liver parenchima in young and old rats].

We studied the effect of dosed normobaric hypoxia during 28 days on functional state and physiological regeneration of liver parenchyma. After completion of experiments in 3 and 9-month old rats we observed an increase in the amount of hepatocytes per unit of tissue area, with hypertrophied nucleus and decreased cytoplasmic area. IGF-I gene expression in 9-month old animals was increased.

[Effect of alimentary deprivation on physiological regeneration of the liver parenchyma in young and mature rats].

It was studied the effects of alimentary deprivation during 28 days on functional state and physiological regeneration of liver. In 3 and 9-month rats it was shown an increase in the amount of hepatocytes per unit of area of tissue, their nucleis were hypertrophied, the area of cytoplasm was decreased, the number of binucleitic hepatocytes in 9-month animals was increased. Thus, our study suggests that a short-term 40% food limitation stimulates physiological regeneration of liver parenchyma.