Structural changes and hemodynamic relations in the microcirculatory bed of the mesentery of the white rat during the period of sexual maturation

Structural changes and hemodynamic relations have been studied in the microcirculatory bed of the white rat small intestine mesentery during sex maturation (from the 3d up to the 10th week of the postnatal development). All calculations are performed regarding the mesenteric segment limited with two intestinal arteries, which is considered as an elementary microvascular module. Complication of the microcirculatory bed construction takes place at the expense of increasing number (nearly five-fold) of microvessels in the segment and increase of the capillary network density. The hemodynamic factor plays a certain role for stimulating the process of the capillary growth. The definitive structure of the mesenteric microcirculatory bed is completed by the 7th week. The main rearrangement of the microcirculatory system during the developmental process from a simple arterio-venular loop up to a complex microcirculatory bed with a branching capillary network is performed within the limits of the mesenteric segment.     

Morphofunctional adjustments in the microvasculature of the conjunctiva of the human eye at different stages of the postnatal period of ontogenesis

By means of the biomicroscopy method under vital conditions, conjunctival microvessels in the eyeball have been investigated in 240 healthy boys 7-17 years of age at the state of rest and at the antiorthostatic action. The rearrangement of the conjunctival microcirculatory bed of the eyeball completes on the whole by 13-14 years of age and is characterized by transition from diffuse to a more refulate structure (the number of the main magistrals lessens, they become larger, the number of capillaries functioning simultaneously decreases, the role of the shunting blood stream becomes more important). With this process in ontogenesis, certain changes in reactivity of microvessels are connected. The quickest and the most adequate responses of the microvessels appear in the development by the time when the definitive composition of the conjunctival microcirculatory bed in the eyeball is formed. Since that time the microcirculatory system reaches its optimal level of functioning and all the processes are performed in the most economic regimen.     

Formation of structuro-functional units of the microcirculatory bed of muscles in the postnatal period of the ontogenesis of the white rat

By means of biomicroscopy, histological methods and scanning electron microscopy topological relationships between the white rat m. cremaster microvessels and changes of their spatial organization have been studied in the postnatal development beginning from the 3d to the 14th week. In the terminal link of the microcirculatory bed zonal functional complexes of microvessels--myoangions are revealed. They represent rather autonomic and regularly repeating constructions of microvessels, having spatial regularity in respect to muscle fibers. With age the myoangion increases its stretchness from 303 +/- 14 in 3-week-old up to (70 +/- 3) X 10 mcm in 14-week-old animals. Capillary density in the m. cremaster during the development decreases from 354 +/- 12 up to 210 +/- 4 mcm, respectively. Distance between the longitudinal capillaries increases from 16.1 +/- 1.3 up to 31.2 +/- 1.8 mcm. Increase of transversal connections takes place in the capillary network, increasing number of the branching knots; this demonstrates certain complication of the nutritive link of the muscle microcirculatory bed. By the time of sexual maturation (6 weeks) there is a sharp decrease of the inflow and outflow coefficients. Higher meanings of the coefficient (0.70-0.74) are noted before sexual maturation period in comparison to that in mature animals (0.53-0.55).     

Morphologic changes in the microcirculatory bed at stages of prolonged experimental fasting in animals

In 40 white male rats with body mass 180-200 g, by means of silver nitrate impregnation, morphological changes have been studied in the blood microcirculatory bed of the small intestine mesentery, spinal trapezoid muscle and eye ball conjunctiva at various stages of a prolonged fasting. With an increasing time of the experiment, a gradual undirected character of the changes in the microvessels is noted. After 3 days of fasting the changes in diameters of the microvessels, comparing to the control ones, have not any significant values in all the organs studied. After 6 days of fasting significant changes in diameters in all the links of the microcirculatory bed of the eye ball conjunctiva and in that of the spinal trapezoid muscle are observed. The microvascular changes are mostly pronounced on the 9th day of fasting. The maximal decrease of the microvessel diameters is noted in the eye ball conjunctiva, and the minimal--in the small intestine mesentery. The changes in the spinal trapezoid muscle are of intermediate character. The highest points of the structural lability gradient fall on the capillary and postcapillary-venular links of the blood microcirculatory bed.     

Redistribution of erythrocytes in the rat mesenteric microcirculation during reperfusion following short-term ischemia

The erythrocyte redistribution in the rat mesentery microvessels and the development of postischemic microcirculatory disturbances were influenced by the thrombosis in narrow parts of arterioles and the increase in leukocyte adhesion to venule walls obstructing the blood outflow. The presence of branches and anastomoses in microvascular bed had a pronounced effect on reperfusion disturbances.     

Effect of helium-neon laser on the microcirculation in blood vessels of the rat pia mater

The sensitivity of rat's microvessels of microcirculatory bed of brain's pia matter was studied by helium-neon laser radiation. Changes in the reactivity by the microscopy findings were studied on the 7, 30, 45, 60, 90th days of animals postnatal development. Laser radiation was used during 30 min. Local changes in all components of the microcirculatory bed were fixed. It is mentioned that in adult rat the expressiveness of arteriole's local widening reaction in the radiated place reduces, but the degree of the reduction is below or over the radiated place, on the contrary, increases. The arteriole diameter in 30-day old rats increases to 59% in comparison to the initial level, and 90th day old animals--to 16%. The degree of reaction's expressiveness depends upon the microvessel diameter and the animal's age.     

Morphofunctional characteristics of microcirculation in the skin of girls 5-17 years of age

In 261 girls year-to-year morphofunctional transformations of spatial composition of the skin microcirculatory bed have been studied at rest and after a dynamic local load. By means of biomicroscopy main regularities in development of the skin capillary network have been revealed in the nail torus in the postnatal ontogenesis. Formation of the microvessels reactivity during various age periods and maturation of mechanisms of the compensatory-adaptive reactions are connected with formation of the definitive composition of the microcirculatory bed, that in girls corresponds to 11-12 years. Qualitative transformations in the skin capillary network bring certain quantitative changes in the structural microcirculatory parameters--increasing diameter of microvessels and increasing density of functioning capillaries.     

Differential Postnatal Development of Monoamine Oxidases A and B in the Blood-Brain Barrier of the Rat

Abstract: We studied the monoamine metabolizing mitochondrial enzyme, monoamine oxidase (MAO), in cerebral microvessels obtained from postnatally developing rats by measuring the specific binding of [³H]pargyline, an irreversible inhibitor of MAO, and the rate of oxidation of three known MAO substrates: benzylamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and tryptamine. MAO activity increased postnatally, with the greatest increase occurring in the second week and reaching a peak at 3 weeks of age. A concomitant increase in MAO of the cerebral cortex also occurred, but was several-fold less than that of cerebral microvessels. Using clorgyline and deprenyl, relatively specific inhibitors of MAO-A and MAO-B, we showed that cerebral microvessels contain both forms of MAO at all ages, but there was a major preponderance in the postnatal development of MAO-B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses of rat microvessels after [³H]pargyline binding also showed two distinct bands of radioactivity at all ages. These two bands corresponded to molecular weights of ∼6.5,000 for MAO-A and -60,000 for MAO-B. SDS-PAGE resuits of brain microvessels obtained from 1-, 14-, and 42-day-old rats confirm the differential postnatal development of MAO-B in rat brain microvessels.     

Cell sources of liver development

The work is devoted to consequent expression of different cell types' protein markers such as vimentin, desmin, cytokeratins 7, 18, 19, stem cell markers CD34 and Bcl-2 at early stages of human prenatal development. Desmin was revealed in sinusoidal liver cells on 3.5-12 weeks of gestation, in mesenchymal cells of ventral mesentery and hepatoblasts on the 4-7 accordingly. During hepatic period of blood formation such desmin positive sinusoidal cells were found to be located close to blood cells. So called "cholangio-" cytokeratins 7 and 19 showed different expression, the first one was found only in cholangiocytes, while cytokeratin 19 existed in hepatoblasts as well until week 15-16 of prenatal development. Mesenchymal cells of ventral mesentery are positive for cytokeratins 18 and 19 even brighter than hepatoblasts in the 4-7 weeks of gestation. Bcl-2 expression was seen in the same periods in most sinusoidal and mesenchymal cells of ventral mesentery. CD34 positive cells are strongly depicted in liver sinusoids from 4th until 9th weeks of gestation, but probably they are not a source of hepatocytes' development in embryonic ontogenesis. Ventral mesentery mesenchyme was negative for this very marker. These results let us suppose that hepatocytes and cholangiocytes may develop from quite different embryonic sources: cholangyocytes grow exceptionally from duodenum epithelial cells, while there is a strong possibility that hepatoblasts formation occurs with participation of mesenchymal cells.     

Change in concentration of cholesterol and lipoprotein fractions of rabbit blood serum in the dynamics of hypercholesterolemia]

Three quantitatively different periods have been detected as a result of 21-week monitoring of blood serum total cholesterol at hypercholesterolemia in rabbits. The first of them (4th week) ends by a relative decrease of cholesterol concentration: the second one (4th-13th weeks) is characterized by its sharp increase; in the third period (13th-21st weeks) the sterol accumulation slows down. Concentration variations of all main lipoprotein fractions are observed in each of the above periods. Their specific features enable us to suppose that in the first period the cholesterol transport system is activated which, probably, reflects the development of adaptation mechanisms of hypocholesterolemia. The second period can be considered as a transition stage from norm to pathology and is most likely, connected with atherogenesis induction. In the third period, in spite of relative stabilization of total cholesterol level clear signs of hyperbeta and hypoalpha dyslipoproteinemias are observed.     

Immunocytochemical study using semi-thin sections of the phenomena of early differentiation in several cell populations of the human fetal adenohypophysis]

Immunocytological investigations have been performed on semi-thin sections of human fetal pituitaries ranging in fetal age from 6 to 26 weeks. Corticotrophs can be revealed by anti-ACTH (1-24), anti-ACTH (17-39) and anti-beta MSH but not by anti-alpha MSH immunesera from the 8th week. Somatotrophs are revealed with anti-human STH from 9th week. Differentiating cells containing only alpha subunits of glycoproteic hormones are present from 8th to 12th week. At 13th week beta subunits of TSH can be revealed immunocytologically in thyreotrophs. Beta subunits of LH or FSH can be detected in same gonadotrophic cells only from 15th week.     

PKB/ Akt 在高脂诱导鼠肾脏损害中的作用

目的:通过建立高脂血症大鼠模型,探讨单纯高脂对肾脏的损伤机制以及胰岛素传导通路中的关键酶PKB/Akt(丝氨酸/苏氨酸激酶)在高脂所致肾脏损害中的变化和意义。方法:高脂高胆固醇喂养Wistar雄性大鼠,建立胰岛素抵抗模型。分别在4周、8周、12周测定大鼠的肾功,包括血尿素蛋(BUN),肌酐(CREA);16周时测定甘油三酯(TG),胆固醇(TC),以及血糖(FBS)和胰岛素(FINS)。8周时行胰岛素增敏剂文迪雅(3mg/kg)灌胃干预四周,并行肾脏病理检查,应用免疫组化法监测PKB/Akt在肾脏的表达。结果:高脂喂饲大鼠4周后,进食量开始减少,体重增加减慢;血BUN、血CREA在4周时已升高,至8周时增加更明显(p<0.001)。文迪雅灌胃四周后肾功改善,但仍高于正常组(p<0.05)。血TG和血TC较正常组升高显著,统计学差异显著(p<0.05)。血胰岛素升高,但胰岛素敏感性降低,胰岛素抵抗指数增加显著,提示胰岛素抵抗形成。肾脏免疫组化PKB/Akt的表达呈现为在肾小球和肾小管分布不均,出现PKB/Akt在损伤较重的肾小球不表达,而在损伤较轻的肾小管表达减弱的现象。结论:饮食诱导的高脂血症可导致健康大鼠产生脂质肾毒性损害以及肾功的降低,并可产生胰岛素抵抗。胰岛素传导通路的损害在肾小球和肾小管表达不同,说明其可能是产生肾脏损伤及胰岛素抵抗的又一原因。胰岛素增敏剂可改善胰岛素抵抗及肾功。     

12周太极拳运动对中老年轻度高血压患者微血管反应性的影响及机制*

目的:研究12周太极拳运动对中老年轻度高血压患者微血管反应性的影响,并探讨微血管反应性变化的机制。方法:将30名轻度高血压患者分为运动组(53.8±6.3岁)和对照组(52.6±7.5岁),两组人数及性别比例相同。运动组进行12周的太极拳运动,对照组保持原先的生活方式且不做其它规律性的体育运动。两组受试者分别于运动干预前、第6周和第12周结束后进行微血管反应性、血压及血清一氧化氮含量 、一氧化氮合酶活性测试。结果:试验前,两组受试者各指标的基础值均无显著差异(P＞0.05)。运动组,第6周微血管反应性、收缩压、舒张压、一氧化氮含量、一氧化氮合酶活性较基础值无显著变化(P＞0.05),第12周微血管反应性、一氧化氮含量和钙依赖型一氧化氮合酶活性较基础值及对照组显著升高(P＜0.05),收缩压和舒张压较基础值和对照组显著下降(P＜0.05)。对照组,第6周、第12周各指标较基础值均无显著变化(P＞0.05)。结论:12周太极拳运动能提高中老年轻度高血压患者微血管反应性、降低血压,并能提高患者一氧化氮含量、钙依赖型一氧化氮合酶活性,内源性一氧化氮生成增加是太极拳运动提高高血压患者微血管反应性的生物学机制之一。     

Effect of the N-terminal fragment of substance P on the microcirculatory system

Biomicroscopic experiments have shown that the N-terminal fragment of substance P (SP1-4), when applied to the rat mesentery, has a considerably lower injuring effect than substance P (SP1-11) itself. SP1-4 activity, as compared to SP1-11 activity regarded as 1, was 0.007 in case of microcirculatory disturbances and venular permeability increase and 0.0007 in case of mast cell degranulation increase. The data obtained suggest that the slightest damaging effect of SP1-4 on microcirculation is combined with anti-stress activity.     

In vivo chemotactic properties and spatial expression of PDGF in developing mesenteric microvascular networks

The recruitment of perivascular cells to developing microvessels is a key component of microvessel assembly. Whereas platelet-derived growth factor (PDGF) signaling is critical for this process during embryonic development, its role from the postnatal stages through adulthood remains unclear. We investigated the potential role of PDGF signaling during microvessel assembly by measuring in vivo the migration of labeled fibroblasts to PDGF in mesenteric connective tissue and by examining PDGF-B and PDGF receptor-beta (PGDFR-beta) expression in microvascular networks during normal maturation. PDGF-B homodimer (PDGF-BB; 30 ng/ml) application elicited a significant (P < 0.05) increase (7.8 +/- 4.1 cells) in labeled fibroblasts within 100 microm of the source micropipette after 2 h. PDGF-A homodimer (30 ng/ml) application and control solution did not elicit directed migration. PDGF-B was expressed in microvessel endothelium and smooth muscle, whereas PDGFR-beta was expressed in endothelium, smooth muscle, and interstitial fibroblasts. Given that PDGF-BB elicits fibroblast migration in the mesentery and that PDGF-B and PDGFR-beta are expressed in a pattern that indicates paracrine signaling from microvessels to the interstitium, the results are consistent with a role for PDGF-B in perivascular cell recruitment to microvessels.     

The involvement of proliferation and apoptosis in the early human gonad development

Distributions of the Ki-67, TP53, caspase-3 and AIFM1 markers were histologically investigated in the 5th to 9th week developing gonads of 12 human conceptuses using immunohistochemical and immunofluorescence methods. Between the 5th and 8th developmental week, proliferation gradually increased in the surface gonad epithelium (26–52 %) and stroma (19–42 %), but then slightly decreased in the surface epithelium (35 %) during the early foetal period. In medulla, low proliferation activity decreased from 15 to 12 % between the 7th and 9th week. At earliest stages of gonadal development, primordial germ cells (PGC) were only rarely TP53 positive. In the 7th and 8th week, almost all PGC-s displayed TP53 positivity, while their number decreased in early fetal period. During the investigated period, caspase-3 reactivity gradually decreased in surface epithelium, while it increased in PGC and medulla of developing gonad AIFM1-positivity first appeared in surface gonad epithelium and then predominantly in PCG-s while caspase-3 characterized different cell populations within the developing gonad. AIFM1 and caspase-3 co-localized only during the migration of PCG-s. The number and distribution of Ki-67, TP53, caspase-3 and AIFM1 reacting cells changed coincidently with development end regression of the sex cords in indifferent and early fetal gonad. Our results indicate that the number of PGC might be controlled by balance of TP53 and AIFM1, leading to caspase-3 independent cell death. Other cell populations are probably eliminated by caspase-3-dependent cell death. Both pathways of cell death seem to operate during early human gonad development, while their intensity varies depending on the cell type and developmental period analysed.     

Results and prospects for the study of the morphologic basis of microcirculation of the blood

The survey of the works, performed during the 11th five-year period in studying general biological regularities of microcirculation, demonstrates certain success in investigations developed in the following directions: functional geometry of the hemo-microcirculatory bed; elaboration of quantitative and qualitative analysis methods of the microcirculatory system elements; functional morphology of the vascular endothelium; experimental analysis of adaptive mechanisms of the microcirculatory bed; clinical-morphological investigations of microcirculation. Formation of structural-functional units, ensuring specialization of microcirculation in organs, forms the base of the functional geometry of the microcirculatory bed. This makes necessary conditions for compartmentalization of some micro-region in an organ and spatial distribution of various liquid media in dependence of certain topology of microvessels. The most perspective ways in development of morphological investigations, concerning the general biological regularities of microcirculation, are discussed.     

Comparative evaluation of the adaptive mechanisms of the microcirculatory bed during dehydration

In total preparations of the white rat small intestine mesentery, impregnated with silver nitrate, as well as under conditions of vital microscopical observations at certain stages of alimentary experimental dehydration, analogous changes in the microcirculatory bed links have been demonstrated. Comparison of quantitative parameters in decreasing diameters of the microvessels, specific for dehydrated preparations has shown a great importance of these changes in the impregnated preparations at the expense of tissue condensation at their histological treatment. The advantages of a complex application of both methods for estimating dynamics of vascular, intervascular and extravascular changes are proved.     

The effect of a 3-hydroxypyridine-class antioxidant on disorders of the microcirculatory system in experimental dyslipoproteinemia and its alimentary correction

The effect of antioxidant (AO) of the 3-hydroxypyridin class on microcirculatory system (MC) disorders of rabbits with dyslipoproteinemia (DLP) and its alimentary correction (the standard ration--9 months) was studied. Aorta, the intestinal mesentery microcirculatory bed, the microvessels adrenergic innervation, erythrocyte morphology were examined. The various lipoprotein fractions and lipid peroxidation (LP) products were studied in venous blood. After AO including into atherogenic diet (ATD) the lipid homeostasis disorders, the LP activation, MC disturbances, anomalous erythrocyte form appearance and atherosclerosis changes in aorta were less pronounced. Under the AO influence when DLP was corrected the initial level of lipid metabolism and LP restored, the MC disorders and the atherosclerosis changes in aorta regressed in a shorter period of time. The interrelation was observed between the DLP level, the structural and functional MC disorders and the extent of aorta atherosclerosis. Thus, DLP and LP correction at the early stages of pathological process can lead to the disappearance of MC disorders, what seems important for the prevention of atherosclerosis. The role of the LP activation in MC disorders in DLP and mexidol effect on them, especially in complex with DLP correction were evaluated.