Biomedical subjects

K A Shoshenko

Publications and source records attributed to K A Shoshenko.

At least 19 recordsLinked to original sources

PubMed2005

[Mitotic activity of pial microvascular endothelium rat in postnatal ontogenesis].

Mitotic activity of endothelium in pial microvessels has been studied with the aid of intra-vessel autoradiography in 4-, 12- and 30-day old rats using these parameters: number of labeled nuclei per vessel or per 100 mcm of its length, or per 1 mm2 endothelial surface area, as well as number of vessels with labeled endothelium cells. The first parameter was independent of vessel diameter. The other parameters had highest value in the pericapillary vessels in all rats. These values decrease with rat age. The highest rate of brain growth was revealed after reaching the greatest mitotic endothelium activity in pial bed.

Aging↗

PubMed2004

[Proliferative activity of blood microvascular endothelium of intestinal mesentery during rat postnatal ontogenesis].

The study of mitotic activity of mesenteric microvascular endothelium cells (EC) in 4-, 12-, and 30-day old rats has been carried out using following parameters: number of labeled nuclei per vessel, or per 100 microm of vascular length, or per 1 mm2 of endothelial surface area, as well as shares of labeled EC and of vessels with labeled EC, have been estimated. The highest density of labeled nuclei was revealed in the pericapillary vessels in all rats. Its values were significantly higher in 12-day-old rats and were the lowest in 30-day-old ones.

Animals↗

PubMed2004

[Skeletal muscle blood bed in growing rats].

Morphometric study of vascular bifurcations and capillaries in biceps femoris artery basin was performed in 2-week old, 1-month old, and adult Wistar rats. Proceeding from the results, the blood tree was digitally reconstructed, and the main haemodynamic parameters in digital simulation were evaluated in this vascular bed: the blood flow velocity, wall shear stress, drop of perfusion pressure, and resistance. The comparison with a similar study of cerebral vascular bed revealed peculiarities of the vascular bed formation and intraorgan haemodynamics in these organs.

Animals↗

PubMed2003

[Mechanisms of changes in blood flow distribution between organs in hens during ontogenesis].

Anatomical and histological investigations of large arteries feeding head, extremities and chorioallantoic membrane were carried out in 11-, 14-, and 18-day old chicken embryos and in 1- and 40-day old Shaver chickens. The numerical relationships between an arterial diameter and a body mass; a vessel length, its external diameter and a wall thickness, were determined. Our data demonstrate that walls of large arteries in the anterior and the posterior parts of the chicken embryo body are different in quantity, composition, and maturity of their tissue components, determining the lumen size and hemodynamic conditions in the blood bed. The vessel growth velocity have been estimated. Ontogenic widening of gastrocnemius and pectoralis muscle capillary beds and of their supplying trunks, was compared. Calculations using the data on organ portions of cardiac output in chicken embryos show the maintenance of similar liner blood flow velocities in different large arteries suring ontogenesis.

Animals↗

PubMed2002

[Coefficient of oxygen diffusion in fibers of the skeletal muscles].

The effective coefficient of oxygen diffusion in muscle fibers (DO2eff) calculated from measured values of O2 critical pressure, O2 intake and fiber diameter in different skeletal muscles in vertebrates turned to be equal to (0.9-1.8) x 10(-6) cm2/s, which is 11 to 33 times lower than O2 in water. In mature animals, DO2eff reaches this value after the fiber diameter has grown to the maximum. In embryos and developing species with thinner myofibers DO2eff is significantly lower. Variations in oxidative metabolism in the fiber do not change DO2eff. Temperature drop in the fiber by 10 degrees C reduces DO2eff by approximately 30%. Modeling of the oxygen regimes in skeletal muscles with low DO2eff demonstrated that increase of the size of the O2-rich interstitium from 9 up to 25% reduces the diffusive resistance to O2 on the way from the capillary to mitochondria by approximately 20% (1); in combined muscles hypoxic areas may appear in the center of fibers with a high O2 demand, particularly when diameters of these fibers are comparatively large (2); the volumetric blood flow in the muscle can be infinitely large and O2 pressure in veins can remain high (the so-called functional shunting).

Age Factors↗

PubMed2001

[Features of capillarization and mitochondria from gastrocnemius and pectoral muscle fibers in chickens of various age].

Using light and electron microscopy, more rapid morphological development of m. gastrocnemius as compared to m. pectoralis was demonstrated in chicken by the 10th day. In m. pectoralis some immature fibers with centrally located nuclei are found, its muscle fibers are generally thinner, contain smaller mitochondria which occupy lesser relative volume, and are surrounded by capillaries, the density of which is half of that in m. gastrocnemius. In both muscles the mitochondria were found to be evenly distributed over the section area of the fibers. In adult birds as well as in chicken capillary density in both oxidative m. gastrocnemius and glycolytic m. pectoralis corresponds to the mitochondrial content in their fibers. In both muscles there exists a distinct concentration of oxygen-absorbing structures within a narrow peripheral zone of the fibers irrespective of the location and number of the surrounding capillaries. This phenomenon is more expressed in m. gastrocnemius. In m. pectoralis mitochondria are smaller at fibers' periphery and larger in their center.

Animals↗

PubMed1998

[Development of the vascular system in brain hemispheres in developing rats].

The blood passage from a major artery to a major vein was digitally reconstructed as well as hydraulic pressure, linear blood flow velocity, wall shear stress, and vascular resistance, following postmortem studies of 2-week old, 1-month old, and adult Wistar rats. The findings suggest that cerebro-cortical vascular bed acquires its functional specifics by the 3rd-4th week after birth.

Animals↗

PubMed1998

[The form of the circulatory tree and the organ specificity of the blood supply].

An original method of quantitative investigation of vascular bed is based on a vascular bed representation as a system of successively connected bifurcations. Parameters of arterial and venous bifurcations were measured in brain hemispheres and femoral biceps of Wistar rats, relationships between these values and stem diameter found, arterial-venous route numerically reconstructed, and its hemodynamic parameters (linear bloodflow velocity, parietal shift tension, hydraulic pressure, and vascular resistance) estimated. Structural functional differences in the vascular bed of the brain and muscle were detected and modeled.

Animals↗

PubMed1996

[The distribution of cardiac output in waking rats with a decrease in body temperature to 2.3 degrees C through cooling or hypoxia].

Heart output distribution (HO) was characterised by incorporation of 15-micron 131-I [correction of 15- 131J]-albumin microspheres after cooling and altitude hypoxia in alert rats. There was no significant change in the HO distribution in experimental rats except a 1.5-fold increase of the skin HO portion and a 1.5-fold decrease of the bone marrow HO portion in hypothermic rats. The latter developed an increase in the blood flow in skeletal muscles and different skin parts as compared with the hypoxic rats.

Animals↗

PubMed1995

[The blood supply to the skeletal muscles of chickens in ontogeny].

During chicken growing, the m. soleus and m. pectoralis fibers become early 10-fold larger, the number of capillaries increase, they elongate and the blood velocity diminishes. A linear relation between PO2 and number of capillaries was revealed in the course of postnatal growth. The arterio-venous oxygen difference increased in the m. soleus' vascular bed and decreased in the m. pectoralis' one.

Aging↗

PubMed1993

[The morphofunctional heterogeneity of the m. cremaster capillary bed in Wistar rats].

Intravital microscopy revealed that 65% of all the m. cremaster's capillary bed were perfused at rest. The capillary functional reserve may play an important part in the topographical heterogeneity of the perfusion. The heterogeneity is a passive mechanism in an increasing number of perfused capillaries, i.e. the "capillary recruitment".

Animals↗

PubMed1992

[The reactions of the arterial and venous microvessels in hypertension and alloxan diabetes in rats].

In hereditary hypertension and chronic diabetes, the number of arterial capillary ends decreased at the arterial side and increased at the venous one in rats. The density of endotheliocyte nuclei decreased in the arteries and increased in the capillaries and veins in the mesentery of the HAHIS rats. The thickening of the venous vessels' walls was more obvious in the SHR rats. The findings suggest different velocities of the proliferative processes in the two types of vessels.

Animals↗

PubMed1991

[The oxygen diffusion coefficient in isolated skeletal muscle fibers].

The oxygen diffusion coefficients in isolated skeletal muscle fibres of Baikal seal and grayling, white rat, chicken were calculated on the basis of experimentally determined curve of dependence of the O2 consumption on pO2 and the radius of the fibres. In all the cases, the diffusion coefficient was smaller in the fibres than in water. The oxygen diffusion coefficient was increased during embryogenesis and postnatal period in chicken. The influence of different parameters of the oxygen transport and of properties of different fibres on the values of the oxygen diffusion coefficients, are discussed.

Animals↗

PubMed1991

[Oxygen tension in rat mixed skeletal muscle at a low diffusion coefficient].

Numerical simulation of the oxygen low diffusion coefficient (1.3.10-6 cm/sec) in a skeletal muscle with three types of fibres with different oxygen demands, has revealed: 1) an enlarged vascularisation of a fibre with high oxygen demand prevents the development of hypoxia because of shortening of the ways of oxygen diffusion from capillaries; 2) in a muscle with external layers consisting mainly of white fibres with low oxygen demand and deep layers of red fibres, the pO2 in the tissue and in the blood flowing from the layers, decrease with the depth.

Animals↗

PubMed1990

[Mitotic activity of the endothelium of different-diameter blood microvessels in the mesentery of Wistar rats].

The technique of intravascular autoradiography of 3H-thymidine labeled nuclei of microvessels endothelia was developed. The density difference of labeled cells in microvascular bed of mesentery was estimated. The maximal density of labelled nuclei was found in pre- and postcapillary vessels, and minimal--in capillaries and large arteries and veins of mesenteric bed. The number of labeled nuclei per vessel was found to be relatively constant. The density of labeled cells in 4-months old rats is less than that in 3 weeks-old ones.

Age Factors↗

PubMed1987

[Structural and functional organization of the microcirculatory bed of the frog and rat mesentery].

The arteriolar and venular network and the blood flow distribution were studied in mesenteric microvascular beds of frogs and rats. Some principles of spatial organization were established: an increase of branching coefficient, a decrease of branching asymmetry with the internal diameter of parent vessel progressively diminishing, the more frequent branching of venous tree including the fragment of a relatively greater volume. The values of geometrical and hemodynamical parameters were different in frogs and rats. Experimental dependence between pressure gradients and vessel radii was found to be exponential, thus being in agreement with prediction of a mathematical model based on physiologically significant criteria.

Animals↗

PubMed1986

[Oxygen consumption of the Baikal seal during unrestrained swimming in a pool and diving of different duration].

In 7 male Baikal seals (14-49 kg) spending 60-90% of the time under water, swimming unrestrained in the swimming pool, the average VO2 ranged from 8.6 +/- 7.01 ml (kg min)-1 for a 14-kg seal up to 4.8 +/- 2.22 ml (min kg)-1 (+ sigma) for adult 49-kg seal. A short forced diving (3-5 min) induced no change of the VO2 level because of stored oxygen. More prolonged diving (10-30 min) induced a 2-3-fold reduction of general VO2 and accumulation of a considerable O2-dept. During 3-5 min, 50-80% of this debt is covered in the 1st phase of recovery. The rest of the debt is covered during 10-40 min, depending on diving duration, body mass and, probably, oxidizing of metabolites of anaerobic exchange.

Animals↗

PubMed1983

[Architectonics of the arterial bed of the cerebral hemispheres in the normal rat and following a stay at an "altitude" of 5600 m].

Post mortem morphometric study of the arterial bed of the brain hemispheres in rats after 90-day stay at "the altitude" 5600 m revealed a noticeably larger diameter of arteries (D), a greater coefficient of their branching, lesser distances between branches (L), larger angles of branch deviation and a longer capillary bed. Calculations based on these data show that amount of arterial vessels and capillaries must increase in hypoxia, their length and linear blood flow velocity (V) must diminish, and the value of V/D2 and epsilon (LV/D2) characterizing the gradient of impetuous pressure and total losses of the impetuosity in the vascular bed must decrease.

Altitude↗