[Reactivity of microvessels in the cerebral hemispheres and the skeletal muscles in chicken during second half of embryogenesis].

At Leghorn hens in the second half of embryogenesis and in 4-day-old chicks are studied reaction volume flow velocity (VF) in the superficial layers of the cerebral hemispheres and in skeletal muscle (Lazer Doppler FIowmetry) after the local influence of norepinephrine and sodium nitroprusside. It is shown that the response to these substances begins to manifest itself in the hemisphere in the last quarter of embryogenesis and authentically expressed by the end of it and in the chickens. It is noted that the response to these substances skeletal muscle VF (according to the new and previously published data on gastrocnemius and pectoral muscle) is also clearly manifested by the end of embryogenesis.

[The tissue oxygen partial pressure in organs of hens in the second half of embryogenesis and in the first days after hatching].

The aim of the study was measure the development chick tissue partial pressure of oxygen (pO2) in the brain cerebral hemispheres, liver, M. pectoralis, M. gastrocnemius, and to estimate the correlation of this index with our previously measured values (laser-Doppler flowmetry) volume blood flow (BF) in these organs. We studied 10-, 15-, and 19-day embryos and 4-day chickens thatwere anesthetized with urethane. pO2 measurements were made in thesurface layers of organs by the membrane amperometric Clark-type O2-electrode with a diameter of about 50 microm of the cathode placed in the center of the sensor with an outer diameter of 3.4 mm. Disclosed noticeable distinction of both the organ tissue pO2 values, and the dynamics of their changes duringthe study period. The most important of them: (1) the lowest pO2 (and BF) is observed in the brain and particularly in the liver of 10-day embryos; (2) in the subsequent period of embryogenesis pO2 in the brain increases 1.9 times (rising and BF) in M. pectoralis it falls by 1.7 times and in the liver.and in M. gastrocnemius changes little wherein the BF in both liver and muscles is not changed, (3) after hatching pO2 in the liver and M. petoralis fold increased (also increasing and BF), and in the brain and M. gastrocnemius, despite the increase BF (greater in the niuscle) did not significant change. In the analysis ofthedata are considered two possible mechanisms of change of tissue pO2 in the developing organs of chickens, one is due to the peculiarities of intracardiac blood flows; and the other is related to thesingularity of the oxyhemoglobin dissociation in the blood capillary bed of organ, determined by the specifics of its oxidative metabolism.

[Aorta, pulmonary artery, and blood flows on them in chickens in the second half of embryogenesis and after hatching].

The aim of the study was to determine changes in the blood flow in arterial trunks (coming out of the heart of chickens) by changes of the lumen of these arteries during embryogenesis (on the 10th, 15th, and 19th days) and 6 days after the hatching. For this purpose, posthumous morphometry of aorta, pulmonary arteries, and arterial (Botallo's) ducts (AD) from their exit from the heart until final extraorgan branching was conducted. It was demonstrated that, in this period, (1) initial lumens of aorta and pulmonary arteries are equal to each other and are equally increased (with temporary stop in last quarter of embryogenesis) with an increase of the body weight (BW); (2) the portion of the right ventricle in a total blood circulation minute volume (BCMV) is somewhat smaller than the portion of the left ventricle, but it approaches equality to it by the end of embryogenesis; (3) with the growth of embryos, the portion of total BCMV flowing through the anterior (before the inflow of AD into the aorta) part of the body decreases; that in the average part increases (from 17 to 31%); that in the posterior part (after bifurcation of aorta), where chorioallantoic membrane (CAM) is located, remains almost unchanged; (4) after the hatching (and disappearance of CAM), BCMV of the left ventricle multiply increases due to the junction of two blood flows from the heart (through the ascending aorta and AD) into a single flow, which flows sequentially by lesser and greater circulations, resulting in multiple increase in the organ blood flow.

[Quantitative relationship of renal blood flow with size and density of glomeruli in rat postnatal ontogenesis].

The aim of the study was to find the quantitative relationship of postnatal changes in the glomeruli anatomic structure with the blood flow in kidneys. Kidney development was studied in 4-, 12-, 30-, and 65-day-old Wistar rats. Diameters of glomerulus (Dgl, microm), afferent and efferent arterioles (Daf and Def), and the glomeruli density (Ngl, mm(-3)) were measured posthumously. Volumes of one ((see text of symbol))V gl, microm3) and all glomeruli (see text for symbol)(sigma(see text for symbol)Vgl, mm3/cm3) and the glomeruli arterioles lumen (Saf and Sef, microm2) were calculated. The renal specific blood flow (SBF per unit of kidney weight, KW) was measured by the laser-Doppler flowmeter (in perfusion units, p.u.) under sodium barbamyl narcosis. We have found that, during postnatal growth, glomeruli morphological parameters vary according to the equations: Dgl = 7.1 (see text for symbol) KW0.41, (see text for symbol)V gl = 187 (see text for symbol) KW1.23, Ngl = 5309 (see text for symbol) KW-0.63 (KW, mg and for one kidney), Saf = 1.1 (see text for symbol)V gl 0.35, and Sef = 6.3 (see text for symbol) V gl 0.14. The renal SBF in 4-, 12-, and 65-day-old rats increases according to SBF = 6.7 (see text for symbol) (sigma( see text for symbol)V gl)0.98. The renal SBF calculated per unit of glomeruli volume varies a little with age.

[Blood flow in skeletal muscles of chicken in the embryonic and early postembryonic periods].

In chicken Leghorn, blood flow volume speed in pectoralis and gastrocnemius muscles was measured on 15 and 19 day-old embryos and at the 1st and the 10th days alter hatching. It was revealed that in the last quarter of embryogenesis BF in muscles did not vary remaining in both muscles in identical limits. Similar BF parameters in pectoralis and gastrocnemius muscles and their age-dependent dynamics were observed at embryos with the detained development (with the body weight 2-fold less than the norm). After hatching, the blood flow in both muscles was grown, on the average, 2.4-fold and remained high by the 10th day, a little decreasing in the pectoralis muscle. It was shown, that increase of a muscular blood flow after hatching was accompanied by different changes of anatomic lumen of the arteries addressed in pectoralis and gastrocnemius muscles: in the former it decreased, in the latter--increased.

[Blood flow in the brain and liver of chicken in embryonal and early postembryonal periods].

In chicken Leghorn, blood flow volume speed (BF, laser-Doppler flowmetry) in the brain hemispheres and in liver was measured on days 10, 14, and 19 of embryogenesis and on day 4 after hatching (in experiments on late embryos and chickens, urethane narcosis was used). It was revealed, that initial BF in investigated organs was 2-fold lower than earlier measured in skeletal muscles. In the liver, low BF remained at all periods, but it grew 5-fold greater after hatching. In the brain hemispheres, the BF during this period grows gradually reaching 4-fold size in chickens. It was shown that blood stream increase in the brain was accompanied by uniform increase in anatomic lumen of internal carotid artery; thus settlement sizes of linear speed of blood flow and wall shear stress remain in it at the same level. Lumen extension of celiac artery during the observation period lags behind increases in a blood stream of in it that leads to increase in it of the named parameters.

[Circulatory system in chicken skeletal muscle in the second half of embryogenesis: shape, bloodstream, and vascular reactivity].

A restructuring of the capillary bed-from the embryonic structure with a three-dimensional network of wide and long protocapillaries to the mature structure with high density of thin and short capillaries along the fibers-has been demonstrated in the chick skeletal muscle on embryonic days 10-19 by morphometric analysis. In this case, the volumetric flow rate and capillary luminal area per cm3 of the muscle remained unaltered, while the blood volume in it significantly dropped. The response of muscle circulation to nitroprusside (increase) and noradrenaline (decrease) appeared in 19-day-old embryos, but this response could develop only under conditions of initially low or high bloodstream, respectively. We propose that the arterial trunk lumen area to the total capillary lumen area remains constant as the intraorganic circulation is formed, which provides for the required linear blood velocity in capillaries.

[Dynamics organ blood flow in rats in postnatal ontogenesis].

In the 4-, 13-, 30-, and 65- 90-day-old Wistar rats the voluminous blood flow rate was measured in liver, kidney, small intestine wall, and in the predominantly white gracilis muscle of femur. A LAKK-01 laser-Doppler flowmeter and its cutaneous (for kidney) and needle (for other organs) probes were used; they provided estimation of blood flow (per organ mass unit) to the tissue depth of about 1 mm. It has been found that the blood flow rates (per organ mass unit fall in liver, intestine, and even more in muscle, whereas increase in kidney, particularly for the first month of life. Calculations show that in adult rats as compared with the 4-day-old pups (with their mass exceeding 22 times) the blood flow to muscle, liver, intestine, and kidney should rise 14, 17, 18 and 43 times, respectively.

[The glomerular apparatus and renal blood flow in rats during postnatal ontogenesis].

In anesthetized Wistar rats of the age of 4, 12, 30 and 65 days, the renal blood flow (RBF) with laser-Doppler flowmetry, diameter, number and density of glomeruli, diameter of afferent and efferent arterioles were measured. We found that during rat development the RBF increased 2.8-fold, the diameter of glomeruli--3.6-fold, diameter of afferent arterioles--1.8-fold, and the efferent arterioles--rose 1.3-fold. The number of glomeruli increased 1.3-fold, but their density decreased 16-fold.

[The muscular blood flow in rats in ontogenesis as measured by the needle probe laser Doppler flowmeter "LAKK-01"].

In anesthetized Wistar rats of the age of 4, 13, 30 and 90 days, blood flow in m. gracilis was measured with the aid of laser-Doppler flowmeter "LAKK-01" with a needle probe. The sharpest postnatal falling of a muscular blood flow was revealed in the first month of life. Features of measurement of the blood flow and biological background by a needle probe in skeletal muscles of rats of various age described.

[Allometric dependences of oxygen transport parameters in skeletal muscles during ontogenesis of domestic fowl].

In domestic fowl, from day 10 of embryogenesis to six month of postnatal life, investigation into the white glycolytic pectoral and red oxidative gastrocnemius muscles allometric dependences of the structural and functional parameters providing muscular fibres by oxygen: speed of breath of an isolated muscular fibre, size of a surface of an external membrane of mitochondria in a fibre, its permeability to oxygen, density of the capillaries located around of a fibre and in all muscle, volumetric speed of a muscular blood flow, and connection of speed of breath of muscular fibres with weight of a body of a bird.

[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.

[Development of the mitochondrial apparatus and blood supply of skeletal muscle fibers during ontogenesis of domestic fowl].

The diameter, length, and numerical density of capillaries, diameter of muscle fibers, size and numerical density of their profiles, and relative volume of mitochondria in them were determined in the chicken red oxidative gastrocnemius and white glycolytic pectoral muscle during development from day 10 of embryogenesis to six month of postnatal life. The bulk blood flow was measured in these muscles by hydrogen clearance during postembryonic development. During embryogenesis, the fibers of gastrocnemius muscle develop and grow at a higher rate, while during postembryonic development, those of the pectoral muscle develop faster. The density of mitochondrial profiles increases during embryogenesis and decreases after hatching, while their mean size increases, especially in the oxidative fibers, but it somewhat decreases in 6-month old chicks. Redistribution of mitochondria by the fiber section during development takes place in both muscles: they are localized predominantly in the center in 18-day embryos and in the periphery, especially in the gastrocnemius fibers, in 6-month old fowl. At hatching, the lengths of capillaries are similar in both muscles, but as chicks grow, the proportion of longer (more than 600 microm) capillaries in the pectoral muscle sharply increases, while their density and bulk blood flow decrease. Ratios were determined between structural parameters of the capillary bed and mitochondria, on the one hand, and oxygen consumption (ml/min per 1 mm fiber and 100 g muscle mass), on the other.

[Skeletal muscle blood bed in growing rats]. / Krovenosnoe ruslo v skeletnoi myshtse u rastushchikh krys.

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.

[Proliferative activity of blood microvascular endothelium of intestinal mesentery during rat postnatal ontogenesis]. / Proliferativnaia aktivnost' éndoteliia krovenosnykh mikrososudov kishechnoi bryzheiki u krys linii Vistar v postnatal'nom ontogeneze.

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.

[Mechanisms of changes in blood flow distribution between organs in hens during ontogenesis]. / K mekhanizmu izmeneniia mezhorgannogo raspredeleniia krovotoka u kur v ontogeneze.

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.