The dynamics of morphofunctional changes in the microcirculation of the pelvic extremity after modeling the chief stages of its replantation]

Under study was the effect of autotransplantation in its "pure form" upon the morpho-functional reconstruction and structural mechanisms of adaptation of the blood and lymphatic links of the microcirculatory bed of extremities during early postoperation period up to 10 days. The pathophysiological state of the extremity sufficiently close to its autotransplantation was obtained by means of circular transection of soft tissues of the medial third of the femur together with the nerves and deep collecting lymphatic vessels. It was found that after modeling the main stages of replantation in the fascia and periosteum of the operated extremity there developed a spasm of the arteriolar link and dilatation of the venular and lymphatic links of the microcirculatory bed. The areas of leukocytic infiltration with the phenomena of diapedesis and microhemorrhages were revealed along the course of postcapillaries and venules in the paravasal connective tissue. The amount of functioning arteriole-venular anastomoses was increased. Against the background of pronounced oedema of soft tissues of the operated extremity the venous pressure increased and the rate of the capillary bloodflow in the skin and muscles decreased. The above changes tend to be reduced by the 10th day after modelling the main stages of replantation of the extremity.     

Morphofunctional changes in the lymph nodes and microcirculatory bed of small-intestinal mesentery of dogs in septic peritonitis after endolymphatic administration of ampicillin

With the aim to study effectiveness+ of endolymphatic (EL) administration of ampicillin (AC), using the model of an acute diffuse septic peritonitis in dogs, the morphological and morphometrical investigation has been performed concerning the state of the lymph nodes (LN), which are regional as regards the pathological focus (pelvic) and remote (tracheobronchial, mesenteric) and hemomicrocirculatory bed (HMCB) of the small intestine mesentery. All LN groups studied are involved in the pathological process, that produces certain increasing disturbances in the structure and cell composition in LN. In 6 h the changes are especially manifested in the pelvic LN, and in 18 h--in the animals without application of AC, or at its intramuscular injection LN lose their typical structure. Their dimensions and number of lymphoid nodules++ and medullary cords decrease, a sharp impoverishment of lymphocytes in LN is observed. By this time critical disturbances in the HMCB structure develop; they are characterized as presence of great amount of avascular areas in the mesentery, extended capillary loops, plasmatic saturation of interstitium. When AC is injected endolymphatically, simultaneously with peritonitis modelling T- and B-dependent zones in LN are preserved, a high volumetric part of lymphocytes is kept in all groups of LN, structure and function of HMCB are normalized. The pronounced delay in development and decreasing manifestation of infective-toxic disorder in LN and HMCB depend on effective concentrations of the antibiotic, produces in the lymphatic system.     

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.     

Effects of 18 days of bed rest on leg and arm venous properties.

Venous function may be altered by bed rest deconditioning. Yet the contribution of altered venous compliance to the orthostatic intolerance observed after bed rest is uncertain. The purpose of this study was to assess the effect of 18 days of bed rest on leg and arm (respectively large and small change in gravitational gradients and use patterns) venous properties. We hypothesized that the magnitude of these venous changes would be related to orthostatic intolerance. Eleven healthy subjects (10 men, 1 woman) participated in the study. Before (pre) and after (post) 18 days of 6 degrees head-down tilt bed rest, strain gauge venous occlusion plethysmography was used to assess limb venous vascular characteristics. Leg venous compliance was significantly decreased after bed rest (pre: 0.048 +/- 0.007 ml x 100 ml(-1) x mmHg(-1), post: 0.033 +/- 0.007 ml x 100 ml(-1) x mmHg(-1); P < 0.01), whereas arm compliance did not change. Leg venous flow resistance increased significantly after bed rest (pre: 1.73 +/- 1.08 mmHg x ml(-1) x 100 ml x min, post: 3.10 +/- 1.00 mmHg x ml(-1) x 100 ml x min; P < 0.05). Maximal lower body negative pressure tolerance, which was expressed as cumulative stress index (pressure x time), decreased in all subjects after bed rest (pre: 932 mmHg x min, post: 747 mmHg x min). The decrease in orthostatic tolerance was not related to changes in leg venous compliance. In conclusion, this study demonstrates that after bed rest, leg venous compliance is reduced and leg venous outflow resistance is enhanced. However, these changes are not related to measures of orthostatic tolerance; therefore, alterations in venous compliance do not to play a major role in orthostatic intolerance after 18 days of head-down tilt bed rest.     

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.     

Hemo- and lymphomicrocirculatory bed of the broad ligament of the uterus in the presence of collateral circulation

Structural adaptation of the vascular bed in the broad ligament of the dog uterus has been studied at various time of the experimental phlebohypertension. Restitution of the circulation after the posterior vena cava occulsion occurs phasically. The venous collateralies are not formed at one time and it is connected with the venous pressure level in the inferiocaval system and with some changes in the construction of the microcirculatory bed. Basing on the morphometry data, a general equation has been derived which reflects dynamics of the microangiological parameters and demonstrates unidirectionness of the adaptive reactions in the vascular bed at the disturbed venous circulation. Using principles of the system-structural analysis and the mathematical graph theory, we consider the microcirculatory system of the broad ligament of the uterus as a graph-system and study the reorganization of the microcirculatory network at a venous congestion. Realization of the compensatory possibilities is reached in the microcirculatory bed by a changed relationships in the number of the intervascular connections. The latter are estimated according to the graph-schemes of the microvascular bed. Morphokinetics of the connections between the vessels is characterized by widening or narrowing the borders of the "adaptive norm" and by changing the microangioarchitectonics. At the same time, there is noted formation of specialized microhemoangioconstructions. Morphofunctional state of the lymphatic system is connected with reorganization of the angioarchitectonics. This is certain manifestation of the law of the lymphatic and blood beds "synergism". Thus, the structural changes of the vascular bed are aimed to support a certain hemodynamic level.     

Morphological evaluation of the state of the structural elements of arterial and arteriolar walls in experimental kidney ischemia

Resetting of arterial and arteriolar wall structural components have been studied in the white rat kidney glomeruli after experimental ischemia (30 min, 1-3 h) without blood flow recovery and with the following recirculation for 3-30 days. The experiments have established that acute renal ischemia caused by the vascular leg ligation for 30-60 min without the following blood flow recovery results in slight microstructural alterations of arterial and arteriolar wall elements. With increased ischemia duration (2-3 h) pathological changes become more prominent and separation of vascular endothelial cells and defibering of the internal elastic membrane take place. In transitory (30-60 min) ischemia of the remaining kidney (one kidney is removed) three days later desquamation of endothelial cells occurs in some arteries. Thinning of arterial walls and overstrain of internal elastic membrane are observed. However, later on (in 30 days) short-term ischemia (30 min) is followed by complete recovery of structural components of arterial and arteriolar walls. In more durable ischemia (2-3 h) of the remaining kidney the recovered blood flow causes marked destructive life-threatening changes in vascular walls.     

Condition of the microcirculatory bed of the bulbar conjunctiva in physiological and pathological pregnancies

By means of biomicroscopic method the bulbar conjunctiva in 150 women (18-35 years of age) have been examined. Of them: 30 healthy women make the control group; the second group includes 60 healthy women at their first and second half of pregnancy; the third group includes 60 women with pregnancy developing against the background of noncomplicated insulin-dependent diabetus mellitus during their first and second half of pregnancy. In the healthy women there are not any significant changes in most of the parameters of the microcirculatory bed during the first half of their pregnancy, and in the second half of their pregnancy a great density of the blood vascular bed is determined. Diameters of all vessels in the hemomicrocirculatory bed are significantly increased, as compared to those in the control group. In the women suffering from diabetus mellitus, during the first half of pregnancy certain changes in the picture of the vascular network is observed, as well as an increased convolution. uneveness in distribution of blood vessels; in the second half of their pregnancy a pronounced deformity of the vacular network is observed, decreasing diameter of afferent vessels and an essential dilatation of postcapillaries and venules are registered. Certain signs of aggregation of blood formed elements is noted.     

Effect of venous congestion on the microcirculatory bed of rat adrenal glands]

Early effect of experimentally induced venous congestion on the rat adrenals is evident in dynamical changes in the microcirculatory bed of the glands. As morphometric data demonstrate, the greatest changes take place in blood vessels of the cortical substance: the capillary diameters are dilated in all the zones, the thickness of the wall in subcapsular and capsular arterioles increases at the expense of hypertrophic smooth muscle elements. Subsequently, venous-arteriolar reaction develops, with capillary diameter approaching the initial size. The data obtained are discussed.     

MRI measures of perfusion-related changes in human skeletal muscle during progressive contractions.

Although skeletal muscle perfusion is fundamental to proper muscle function, in vivo measurements are typically limited to those of limb or arterial blood flow, rather than flow within the muscle bed itself. We present a noninvasive functional MRI (fMRI) technique for measuring perfusion-related signal intensity (SI) changes in human skeletal muscle during and after contractions and demonstrate its application to the question of occlusion during a range of contraction intensities. Eight healthy men (aged 20-31 yr) performed a series of isometric ankle dorsiflexor contractions from 10 to 100% maximal voluntary contraction. Axial gradient-echo echo-planar images (repetition time = 500 ms, echo time = 18.6 ms) were acquired continuously before, during, and following each 10-s contraction, with 4.5-min rest between contractions. Average SI in the dorsiflexor muscles was calculated for all 240 images in each contraction series. Postcontraction hyperemia for each force level was determined as peak change in SI after contraction, which was then scaled to that obtained following a 5-min cuff occlusion of the thigh (i.e., maximal hyperemia). A subset of subjects (n = 4) performed parallel studies using venous occlusion plethysmography to measure limb blood flow. Hyperemia measured by fMRI and plethysmography demonstrated good agreement. Postcontraction hyperemia measured by fMRI scaled with contraction intensity up to approximately 60% maximal voluntary contraction. fMRI provides a noninvasive means of quantifying perfusion-related changes during and following skeletal muscle contractions in humans. Temporal changes in perfusion can be observed, as can the heterogeneity of perfusion across the muscle bed.     

The effect of ionizing radiation on the vascular bed of the skin in ontogeny. The function of the microcirculatory bed of the skin in the fetuses of white rats sublethally irradiated]

Albino female rats were exposed to X radiation (5 Gy, 180 kV, 10 mA, filter 0.5 mm Cu) on days 10-15 of pregnancy. After 3 and 7 days they were sacrificed (under ether anesthesia) and fetuses were extracted. The status of the lympho- and hemomicrocirculatory beds (LMCB and HMCB) of the fetus back skin was studied by the macro- and microscopic methods. As early as day 3 of radiation sickness the diameter of LMCB vessels increased by 1.4-1.9 times, whereas changes in GMCB were less pronounced. On day 7, there was a progressive increase in dilatation of LMCB vessels, alongside with the narrowing of large units (arteries and veins). The development of the connective framework of the fetus skin was retarded.     

Blood volume, the venous system, preload, and cardiac output

Cardiac output is determined by heart rate, by contractility (maximum systolic elastance, Emax) and afterload, and by diastolic ventricular compliance and preload. These relationships are illustrated using the pressure-volume loop. Diastolic compliance and Emax place limits determined by the heart within which the pressure-volume loop must lie. End-diastolic and end-systolic pressures and hence the exact position of the loop within these limits are determined by the peripheral circulation. In the presence of minimal sympathetic tone, some 60% of total blood volume is hemodynamically inactive and constitutes a blood volume reserve (the unstressed volume). The remainder of the blood volume (the stressed volume) and the compliance of the venous system determine the venous pressure. This venous pressure together with venous resistance determines venous return, right atrial pressure, cardiac preload, and hence cardiac output. Venoconstriction causes conversion of unstressed volume to the stressed volume, the blood volume reserve is converted into hemodynamically active blood volume. After hemorrhage this replaces the lost stressed volume, while in other situations where total blood volume is not reduced, it allows a sustained increase in cardiac output. The major blood volume reserve is in the splanchnic bed: the liver and intestine, and in animals but not man, the spleen. A major unsolved problem is how the conversion of unstressed volume to stressed volume by venoconstriction is reflexly controlled.     

Status of the circulatory bed of the vascular membrane of the eyeball and retrobulbar structures during experimental venous stasis

In 43 test animals the state of the blood bed in the retrobulbar formations and the eyeball vasular tunic has been studied under venous congestion produced by ligation of the anterior vena cava (in dogs) and both external jugular veins (in rabbits). A complex of histological, histotopographic, morphometric and variation-statistical techniques has been used. The results obtained demonstrate that disturbances in the venous outflow in the anterior vena cava system produce certain responses in all parts of the retrotubular adipose tissue, of the eyeball muscles, of the optic nerve tunics, of the vascular tunic. Certain stageness is noted in the course of venous congestion. Places of the greatest morphological changes in the eyeball vascular tunic are determined. They are zones of vorticose veins formation and the area corresponding to the posterior pole of the eyeball. The analysis of the specific areas of the intermuscular arteries and veins cross sections demonstrates that in the reaction of these vessels to the different venous outflow in the anterior vena cava system these is certain unevenness in different ofthalmic muscles.     

Changes in the respiratory muscles and their microcirculatory bed during exposure of the body to chronic hypoxia and its aftereffects

Changes of the respiratory muscles have been studied under the effect of a rarefied atmosphere when the pressure is 560 mm Hg (2,500 m), 405 mm Hg (5,000 m), 286 mm Hg (7,500 m) and during the period of their aftereffect. The experimental group consists of 260 and the control group--of 130 white rats. Adaptation of the respiratory muscles to the effect of the rarefied atmosphere at the pressure of 560 mm Hg takes place mainly at the expense of certain functional changes of the microcirculatory bed and hypertrophy of the muscle fibers. The period of aftereffect is characterized with normalization of these phenomena. Adaptation of the respiratory muscles at the pressure of 405 mm Hg takes place at the expense of hypertrophy of the muscle fibers, small destructive changes and a complex rearrangement of the microcirulatory bed. During the period of aftereffect, by the 40th day no destructive changes are noted in the muscle tissue. The capillary bed undergoes some rearrangements by the 42d -56th day with increasing quantitative indices per area unit. This results in improvement of the muscles nutrition. In the respiratory muscles at the pressure 286 mm Hg, atrophic changes in the muscle fibers take place at certain stages of the experiment. Essential destructive changes are observed, rearrangement of the microcirculatory bed with decreasing convolution of the longitudinal capillaries and a decreasing number of the transversal capillaries are noted by the end of the experiment. During the period of aftereffect, by the 56th day, the external and internal intercostal muscles completely restore their structure, and in the diaphragm the destructive changes remain. By the same time, the microcirculatory bed becomes more rare at the expense of decreasing capillarization of the muscle fibers and a decreasing number of the transversal capillaries.     

Intraorganic venous bed of the stomach cardia in children during the first 3 years of life

The intraorganic venous bed of the gastric cardial part has been studied in 27 organs, obtained from children corpses of both sex beginning from birth up to three years of life. They died from causes that were not connected with gastric or vascular system pathology. The results of the investigation prove the presence of mucous, submucous, muscular and serous-subserous venous plexuses in the wall of the gastric cardial part in children of the first three years of life. Every membrane of the stomach wall has its specific structure of the venous link in the microcirculatory bed. In the stomach mucous membrane already in a newborn there are complexly built microcirculatory pathways. Age changes are mostly expressed in the venous link of the gastric mucous membrane; this is probably connected with functional activity of the given layer of the organ. The largest venous vessels are situated in the gastric submucous base. By the end of the newborn period and, especially fully, during the successive age periods immune protection of the gastric wall is formed as an accumulation of lymphoid tissue to an antigenic effect of food. In these age groups certain structural mechanisms of blood outflow from the gastric wall appear.     

Exogenous androgens decrease the length of the luteal phase and increase the length of the follicular phase

This study investigated the effects of exogenous androgens on the menstrual cycle of eight transsexual females. It was found that the luteal phase decreased from 13.7 +/- 0.8 to 11.6 +/- 0.8 days, whereas the follicular phase increased in length from 13.5 +/- 0.6 to 15.3 +/- 0.6 days. With the testosterone levels attained in venous blood (+/- 4.5 nmol/l) ovulation continued, judged by the rise of basal body temperature and the increase of oestrogen and progesterone blood levels. These results relate hyperandrogenism to luteal insufficiency.     

Structural features of the intrinsic venous bed of the human urinary bladder

The intraorganic veins of the human urinary bladder have been studied in a vast sectional material. The veins within the organ make an enormous multilayered plexus which is differently organized in various layers of its wall. Abundant anastomoses, multiplicated ways for outflow from every layer, manifested interactions between the venous plexuses are specific for the intraorganic venous bed of the urinary bladder. The structures for an active regulating the hemomicrocirculatory blood stream are widely presented in the urinary bladder. In its every tunic certain specific morpho-functional features for organization and adaptation of the intraorganic venous bed are revealed.     

Development of the microcirculatory bed of the human tongue in the prenatal period

Morphofunctional regularities of formation and development of the blood microcirculatory bed in the human tongue have been studied in the prenatal period of morphogenesis. 119 human embryos and fetuses at the age of 5 weeks--9 months have been investigated. A complex of methods have been used: common histological (hematoxylin--eosin, after van Gieson and Mallory), injection of the lingual vessels with 20% suspension of Indian ink--gelatin, transmissive electron microscopy. General regularities of organogenesis, stages of the blood microcirculatory bed development and peculiarities of the process on formation of the primary protocapillary lingual blood bed are revealed. Regularities in structure of the terminal vascular constructions are studied for each structural element of the organ--mucosal membrane, muscles, glands, lingual tonsil. For these elements at the ultrastructural level certain features of the organic specificity in the structure of the blood microcirculatory bed links are determined.     

Effect of helium-neon laser radiation on restoration of the structure of the microcirculatory bed and neurocytes of the small intestine following experimental ischemia

Influence of helium-neon laser lg-75 rays on the microcirculatory bed and neurocytes of the small intestine after its experimental ischemia has been studied. When a normal small intestine is radiated, dilatation of the luminal diameter is observed in all links of the microcirculatory bed (MCB) and also hypertrophy of neurocytes, when phenomena of distrophic processes are absent. In 30 days after 3-hours' ischemia of the intestinal loop and its successive radiation, spasm of arterial and dilatation of the venous link of MCB is registered; they normalize by the 45th day. In the control, after ischemia (without radiation) in 45 days venous plethora of the vessels in the intermuscular plexus of the intestinal wall is kept. In the nervous elements of the muscular-intestinal plexus at early stages of the experiment against the background of ischemia reactive and distrophic changes appear. By the 30th day after radiation, the volume of neurocytic bodies increases, processes grow out, nuclear-cytoplasmic index increases. Nonspecific character of the laser rays is supposed; their effect is realised via regional microvascular and nervous formations.     

WISE 2005: altered cerebrovascular autoregulation after 60 day head-down bed rest

We tested the hypothesis that 60 days of head-down bed rest (HDBR) would affect cerebrovascular autoregulation and that this change would be correlated with changes in tolerance to the upright posture. Twenty-four healthy women (32 +/- 4 yrs) participated in a 60-d bed rest study at the MEDES Clinic in Toulouse, France. End tidal CO2 (ETCO2), continuous blood pressure (BP), middle cerebral artery (MCA) velocity and time to presyncope (endpoint) were measured during an orthostatic tolerance test conducted before/after bed rest. Given the large range of change in tolerance even within assigned countermeasure groups, we separated subjects for this analysis on the basis of the change in endpoint (Delta endpoint) pre- to post-bed rest. Autoregulation and CO2 responsiveness were evaluated on a different day from a two-breath test with intermittent hypercapnic exposure. Autoregressive moving average (ARMA) modeled the two confounding inputs, BP and CO2, on cerebrovascular blood flow. The cerebrovascular resistance index (CVRi) was expected to decrease following a decrease in BP at the MCA to assist in maintenance of cerebral blood flow. Subjects with the smallest Delta endpoint after bed rest had a 78% increase in the gain of the BP --> CVRi response. Meanwhile, the groups with greater decline in orthostatic tolerance post-HDBR had no change in the gain of this response. ETCO2 was lower overall following HDBR, decreasing from 41.8 +/- 3.4 to 40.2 +/- 3.0 in supine rest, 37.9 +/- 3.4 to 33.3 +/- 4.0 in early tilt, and 29.5 +/- 4.4 to 27.1 +/- 5.1 at pre-syncope. There was however, higher MCA velocity at any ETCO2 for post- compared to pre-HDBR. In summary, changes in autoregulation were found only in those subjects who had the smallest change from pre- to post-HDBR orthostatic tolerance. The changes may assist in buffering changes in cerebral blood flow during orthostatic hypotension post-HDBR. The reduction in ETCO2 after bed rest might be due to a change in chemoreceptor response to blood CO2, but the cerebrovascular system seems to have completely compensated.