Systemic and organic changes in the microcirculatory bed in experimental dehydration of the body

Among systemic mechanisms of microvascular reactivity of the musculus spinotrapezius, pancreas and small intestine mesentery at dehydration, a special role play the changes directed to maintenance of harmony between the capacity of the blood bed and volume of the circulatory blood, morpho-functional factors on regulation of hemodynamics, as well as mechanism of liquor resource++ elimination from the blood bed. The organic peculiarities of the microvascular reactivity at dehydration are determined by topic and quantitative character of their changes.     

Comparative morphometry of vessels of the microcirculatory bed of the cat pericardium in impregnated preparations and during in vivo microscopy

In impregnated (with silver nitrate) preparations of the cat pericardium and in photonegative pericardial microvessels photographed in vital experiments, diameters of the main vascular groups in the microcirculatory bed (arterioles, precapillaries, capillaries, postcapillaries and venules) were comparatively estimated. When impregnated, the vascular diameter decreases; the degree of the changes is not equal and depends on the wall structure. Therefore, when studying impregnated preparations, it is necessary to introduce the correction coefficients in order to make the data obtained comparable with the vital ones.     

The microcirculatory bed of the human heart

Using a complex approach in studying microcirculatory bed of the human heart, possibilities of scanning electron microscopy of corrosive preparations, those of silver nitrate impregnation after V. V. Kuprianov are demonstrated. The silver nitrate impregnation makes it possible to study the wall structure of the microcirculatory pathways, to analyse arrangement of nuclei in the endothelial and muscle cells of the microcirculatory links, to reveal together with the vessels the surrounding tissues. Scanograms of the corrosive preparations of the arterioles demonstrate "circulatory strips", that are absent in the venular part. The relief of the luminal casts of the microcirculatory bed vessels in the human heart is presented as impresses of nuclei of the endothelial and smooth muscle cells. Peculiarities in form and distribution of these nuclei in various links of the microbed are demonstrated.     

Rearrangement of the microcirculatory bed of the skin pedicle flap during the development of complications]

Rearrangement of microcirculatory pathways in the skin was studied without injecting the vessels when the peduncles of a regular size and the peduncles with the ratio of their length to width as 5:1 were formed. In the first case, rearrangement of the microcirculatory bed was revealed to have an adaptive character. In the second case, continuously increasing gross morphological disorders resulting in venous congestion and contributing to necrosis of the peduncle were revealed.     

Index of microcirculatory changes in experimental dehydration in animals

On the basis of morphokinetic synthesis principles the method of determination of summarizing criterion of microcirculatory system changes was developed. It consists of marked characteristics of changes of a number of the most important morphofunctional phenomena of each of this system compartments -- interstitial, lymphatic, blood and cellular -- with their successive summation to obtain the systemic microcirculation index. The experimental dehydration in rats being a model has shown that systemic microcirculatory index was 2 times as large in 3 days of dehydration, more than 3 times -- in 6 days, and 4, 5 times -- in 12 days. In the initial stage of the experiments maximal changes were found in interstitial compartment of the microcirculatory system. The intermediate period of dehydration differed by predominant changes of vascular compartment when the lymphatic phenomena were more evident than the hemomicrocirculatory ones. In the later stage of dehydration the cellular component changes of tissues and organs were predominant.     

Development of the uterine microcirculatory bed in postnatal ontogeny

Age peculiarities of common structure of the microcirculatory pathways, specific volumes and amount of microvessels, zonal parameters of pericapillary microcirculation of metabolites, glycosamine glycans and glycoproteins contents, phosphatase and ATPase activity, collagen and elastic fibers of the microcirculatory bed vessels have been studied in 190 unchanged uteri, beginning from 36-week-old fetuses up to 35 years of age. The microcirculatory bed of myometrium during the period of postnatal ontogenesis investigated possesses a polymer-homonomous structural organization; its base make myoangiomas, including the terminal arteriole with precapillaries and collecting venule, that run from it. Similar structure of the myometrium microcirculatory pathways is already observed in fetuses of late antenatal period. In endometrium formed glanduloangionomas are revealed in the prepubertal age. Increase in glycosamine glycans contents is stated in the microvessel walls and in the uterine stroma during the process of its development. Compensatory-adaptive changes in the uterine microcirculatory bed are described during the newborn period up to the puberty. Functionally mature structures of the microcirculatory pathways in the submucosal and vascular layers of myometrium, endometrium and in the cervix uteri are found to be formed earlier than in other areas of the organ.     

Morphometric findings in the microcirculatory bed of the sigmoid serosa during the fetal period in man

During fetal life, formation and arrangement of the microcirculatory bed in the serous membrane of the sigmoid colon correspond to the growth and functioning of the latter at different stages of ontogenesis. Two periods in the development of the microcirculatory bed of the serous membrane of the sigmoid colon are revealed: the first period coincides with the first half of the fetal development when capillary growth is considerable, i.e. with the growth of metabolic part in the microcirculatory bed; the second period coincides with the second half of the fetal development when intensified growth of the sigmoid portion of the large intenstine and its transport sections in the microcirculatory bed (arterioles, precapillaries, postcapillaries, venules) are observed.     

Loss of adaptive mechanisms during aging.

Factors contributing to modifications in the capability for enzyme adaptation as an expression of aging are reviewed. Specific examples of altered enzyme adaptations during aging include the responses of hepatic glucokinase activity to glucose and hepatic tyrosine aminotransferase activity to starvation in Sprague-Dawley rats. These impaired enzyme adaptations apparently are not the consequence of alterations in hepatic function during aging. Instead, they reflect disturbances in extrahepatic hormonal regulatory mechanisms. Specific examples include modifications in the control of circulating levels of insulin glucagon, corticosteroids, and thyroid hormones. Age-dependent changes in the regulation of circulating levels of insulin probably originate within the impaired ability of pancreatic islets of Langerhans to secrete the hormone in response to glucose. The rationale for exploiting this experimental approach as a means to understand biological aging is discussed.     

Organ and tissue-specific properties of the microcirculatory bed of the heart

The auricular and ventricular microcirculatory bed has been studied in persons of mature age, not suffering from any cardio-vascular diseases during their life. As a whole, 48 objects have been studied. The microcirculatory bed has been revealed in sections of the cardiac wall 70-100 mcm thick using silver nitrate impregnation after V. V. Kuprianov. Organ- and tissue-specific properties of the vascular microcirculatory bed are revealed in interrelations of the vessels and the structural elements of the cardiac wall (myocardium, and connective tissue structures), in position of nuclei of the endothelial cells of the capillary wall and in places of the capillary branchings. Principle differences in structure of the auricular and ventricular microcirculatory bed are demonstrated. The notion the organ- and tissue-specific properties of the microcirculatory bed vessels is discussed.     

Innervation of the microcirculatory bed of the human trigeminal nerve]

The investigation of film preparations and histological sections of human trigeminal nerves impregnated with silver nitrate and treated after Gomori, Falck--Hillarp demonstrated a rich innervation in the intraneural blood vessels. The most various and complex interconnections of the neural structures were noted in arterioles and venules of the node capsule, epineurium and external layers of perineurium of the trigeminal nerve branches. On the vessel walls of these layers, neural plexus were revealed. Sensitive innervation of the neural blood vessels mainly performed by posvalent tissue-vascular receptors. In the walls of intraneural vessels, adrenergic and cholinergic neural plexus are revealed.     

Vascular anastomoses of the blood microcirculatory bed of the human heart

Using a complex of morphological techniques both injective and non-injective, scanning electron microscopy including, the hemomicrocirculatory bed and vascular anastomoses have been studied in various parts of the human heart. In most cases anastomoses between the microcirculatory links are realized at the level of capillaries, precapillary arterioles and postcapillary venules. Venulo-venular anastomoses are demonstrated in the myocardium. Existence of terminal arterioles is discussed.     

Ultrastructural changes in the microcirculatory bed and filtration-reabsorption barrier of the kidney during temporary ischemia after unilateral nephrectomy

Ultrastructure of cellular elements of the microcirculatory bed and filtration-reabsorption barrier has been studied in 150 mature white rats, in which vascular fasciculus of the left kidney has been compressed for 30 min, 1-2 h with a subsequent restoration of the blood stream in the organ undergone ischemia on the 3rd, 7th, 14th, 30th, 60th, 180th, 360th days under conditions of the preliminarily right kidney nephrectomy. On the 3rd day after ischemia of the remained kidney for 30 min, structural components of the walls of the glomerular arterioles and those of the filtration-reabsorption barrier undergo certain ultrastructural changes, that with time elapsed (7, 14 days) gradually pass away, and amount of cells with hypertrophic processes increases. Ischemia for 1 h in the remained kidney with subsequent restoration of the blood stream on the 3rd, 7th days produces in the structures mentioned more pronounced destructive changes. During subsequent compensatory hypertrophy (the 30th, 60th days) of the remained kidney after its ischemia, in the microcirculatory bed elements and in the convoluted canal epitheliocytes intracellular regenerative and hyperplastic processes develop. However, ischemia for 2 h in the remained kidney produces severe destructive-necrotic phenomena in ultrastructure of the microcirculatory bed and of the filtration-reabsorption barrier.     

Study of endothelium-dependent blood oscillations in the human skin microcirculatory bed

Cutaneous microcirculation parameters were studied with laser Doppler flowmetry in healthy volunteers. To investigate endothelial-dependent peripheral blood flow oscillations the iontophoresis of 1% acetylcholine solution was carried out. To estimate the contribution of rhythmical components in blood flow signal the continuous wavelet-transform spectral analysis was used. To reveal correlation between microcirculation parameters under study the correlation analysis was used. The microcirculation index was shown to be the factor producing cross-correlation dependences. The only positive significant correlation between the blood flow oscillation amplitude in the range of endothelial activity normalized to mean microcirculation index at rest and maximal microcirculation index during the iontophoresis of acetylcholine was revealed.     

Ultrastructural changes in the microcirculatory bed of the lungs in endotoxin shock

The electron microscopic study of the lungs during the initial and intermediate stages of endotoxin shock has revealed the manifestations of thrombo-hemorrhagic syndrome. Three days later interstitial fibrosis developed. Ultrastructural alterations of microcirculation become the basis for the formation of acute pulmonary failure.     

Structure and function of the microcirculatory bed in the preserved heart]

The morphological analysis of the state of the heart during hypertermal perfusion with different conservants reveals clear dependence of the microcirculation and the activity of the heart upon the type of the conservant. Perfusion with a salt solution and hemodilution is accompanied by pronounced disorders in microcirculation and unsatisfactory parameters of the cardiac activity. Conservation with cryoprecipitated plasma is characterized by comparatively less microcirculatory disorders, but fails to give a reliable safety of the heart. When using medium 199, changes in microcirculation were found to be minimal and parameters of cardiac activity were satisfactory. In the complex of non-specific changes in microcirculatory vessels the maximum structural lability was revealed in blood capillaries and vessels of the postcapillary-venular link.