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Results for “Microcirculation”

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At least 973 records · Page 54Linked to original sources

PubMed1990

[Effects of thermal factors on the state of microcirculation of the small intestine in acute ischemia].

The influence of normo- (38 degrees C), hyper- (42 degrees C) and hypothermia (20 degrees C) on microcirculatory disturbances caused by acute local ischemia of the small intestine was investigated with the help of biomicroscopy as well as morphological methods. Ischemia was modeled by ligation of the intestine look eventrated through the abdominal wall incision of a rat onto the microscope stage for 1 h. It was shown that hyperthermia intensified microcirculatory disorders and stimulated destructive processes in tissues and hypothermia promoting microcirculation and decreasing metabolism and restrained the development of these processes. Important peculiarity of the microvascular response to ischemia, hyper- and hypothermia was revealed: heterogeneity of the reaction of different parts of microvascular bed. Appropriate evaluation of the microcirculation state in such conditions can be obtained taking into account not only the qualitative character of microvascular reaction but also an extent of this reaction manifestation in different parts of microvascular bed.

Animals↗

PubMedDate not supplied

[Microcirculation of the nasal mucosa in persons of the older age groups].

Specific features of microcirculation of the mucous membrane of the nasal cavity of 32 patients over 57 years were investigated. Additionally, microcirculation of the mucous membrane of the nasal septum and wall of untreated rabbits and rabbits, that for 5 months were on a cholesterol enriched diet, was examined. It was shown that in both cases the transport function of capillaries and, consequently, the structure of the mucous membrane deteriorated which may contribute to the development of persistent rhinosinusitis.

Age Factors↗

PubMed1990

[Cerebral microcirculation during increased intracranial pressure--assessment with reflectance photometry].

The cerebral microcirculation under increased intracranial pressure was evaluated by using reflectance photometric method. The values of tissue hemoglobin (IHb) and its oxygen saturation (ISO2) detected by this method were evaluated in cat brain tissue. The correlation between IHb and content of cortical hemoglobin subunits in vitro was high. High correlation between ISO2 and blood oxygen saturation in superior sagittal sinus was also noted in hypoxic hypoxia. Thus, the reflectance photometric method was revealed to be applicable for evaluation of regional hemoglobin content and oxygen saturation. Using this method the cerebral microcirculation was studied in an increased intracranial pressure model produced by injection of artificial CSF into the cisterna magna in cats. Regional cortical cerebral blood flow (CBF) was measured simultaneously by thermal diffusion method. During decrease of perfusion pressure down to 40 mmHg with preservation of CBF, compensatory increase of IHb was not observed, but IHb rather gradually decreased. The decrease of IHb would be due collapse of capacitance vessels by increased intracranial pressure. Cerebral ISO2 was stable as well as CBF. Less than 40 mmHg of perfusion pressure, ISO2 started to decrease in association with CBF and IHb. Since ISO2 seems to be closely related to the tissue oxygen extraction the change of ISO2 reflect the CBF and tissue cerebral oxygen metabolism. Present study suggest the evaluations of IHb and ISO2 were an useful monitoring indexes in various cerebral disorders.

Animals↗

PubMed1990

[Single-photon emission-computed tomography of the head using labelled amines in visualizing the cerebral microcirculation].

The authors presented clinical material on cerebral hemodynamics in patients with neurological pathology in suspected tumor vascular cerebral diseases and craniocerebral traumas. Investigation of cerebral microcirculation was performed using a multidetector single-photon emission tomograph "Testoscan" (USSR) after iv administration of 99mTc-hexamethylpropilene-amyloxine. This radiopharmaceutical is good for the evaluation of cerebral perfusion and gives a clinician rich information on cerebral microcirculation.

Adult↗

PubMed1990

Effect of Ginkgo biloba on fluidity of blood and peripheral microcirculation in volunteers.

In a randomized placebo controlled single-blind cross-over study of n = 10 apparently healthy subjects the influence of Ginkgo biloba (Kaveri) on blood fluidity and cutaneous microcirculation was studied. Microcirculation was measured before and every 30 min for 4 h after administration of Ginkgo biloba; fluidity of blood was determined before and after 1, 2 and 4 h. Significant changes in blood pressure or heart rate were found neither during Ginkgo phase nor placebo phase. Haematocrit, plasma viscosity, erythrocyte rigidity, thrombocyte and leukocyte count as well as thrombocyte aggregation and the number of circulating thrombocyte aggregates were also not influenced by the Ginkgo nor the placebo solution. In contrast a remarkable influence on the erythrocyte aggregation was observed: comparing two samples a significant decrease by 15.6% (p less than 0.001) with regard to the initial value was observed after 2 h. The blood flow in the nail fold capillaries also increased significantly by about 57% (p less than 0.004) 1 h after administration.

Adult↗

PubMed1990

[Effect of ulinastatin on microcirculation under hemodilution and hypothermia].

Microcirculation during hemodilution and hypothermia under ether anesthesia treated with or without ulinastatin was studied by means of rabbit ear chamber. Sixteen rabbits were divided into 2 groups; 8 rabbits without ulinastatin treatment (C group) and 8 rabbits treated with ulinastatin (U group). Surface cooling to 20 degrees C and rewarming were performed. No significant differences between the groups were found in blood pressure and heart rate, but pulse pressure in U group was significantly larger (P less than 0.01) than that in C group. Pulmonary edema occurred in 3 rabbits in C group during rewarming. The results suggest that ulinastatin inhibited edema formation in U group. In C group, the blood flow velocity was very slow and the blood flow rate was very small at 20 degrees C in arterioles and venules. In U group the flow velocity and the flow rate were well maintained at 20 degrees C in arterioles and venules. It is concluded that ulinastatin is effective in maintaining microcirculation during hemodilution and hypothermia.

Animals↗

PubMed1975

The problem of tissue oxygenation in diabetes mellitus. I. Its relation to the early functional changes in the microcirculation of diabetic subjects.

The underlying cause leading to the reversible functional changes in the microcirculation of insulin-dependent diabetic subjects early during the disease prior to any clinical signs of retinopathy and nephropathy (functional microangiopathy) is discussed. It is suggested that the initial microvascular dilation observed in diabetics is due to an autoregulatory response to relative tissue hypoxia providing an increased tissue perfusion in order to improve tissue oxygen delivery. Supporting evidence for this suggestion is derived from the findings that diabetics simultaneously may show increased tissue oxygen consumption and decreased ability of the circulating blood to release oxygen to the tissues. The latter defect is likely to be caused by two interrelated factors: 1. an increased proportion of haemoglobin A1c with high oxygen affinity, and 2. difficulties of maintaining a sufficiently high concentration of plasma inorganic phosphate in order to provide an optimal 2,3-diphosphoglycerate (2,3-DPG) content in the erythrocytes. The basal oxygen demand of diabetics may fluctuate even within a few hours dependent upon the state of metabolic control and is increased at times of poor regulation. Hence, diabetics may suffer from innumerable cellular hypoxic injuries, which during the first years of the disease are counteracted in the microcirculation by an autoregulatory response. These microvascular reactions associated with increased plasma permeation may over the years be of major importance for the development of the degenerative microangiopathy in diabetes.

Diabetes Mellitus↗

PubMed1990

[Effect of radix Paeoniae rubrae extract on mesenteric microcirculation].

The effect of radix Paeoniae rubrae extract on mesenteric microcirculation was studied in 20 scalded SD rats. It was found that this drug effectively prevented some disturbances of mesenteric microcirculation induced by burn. It inhibited the contraction of arterioles, decreased the adhesion of leucocytes on the venous wall, reduced and delayed the aggregation of erythrocytes in microvessels.

Animals↗

PubMed1978

[State of the microcirculation in periarteritis nodosa based on morphological and biomicroscopic data].

The status of microcirculation in periarteritis nodosa was studied by impregnation method (serous membranes) and biomicroscopy (eyeball conjunctiva). Pathological and adaptative changes in terminal vessels were found. It is suggested that the involvement of microcirculation ways in this disease is systemic and that morphological changes in microvessels are comparable to biomicroscopic changes.

Adolescent↗

PubMed1989

[Cutaneous microcirculation in infectious endocarditis].

Nailfold capillary microscopy was used to study the microcirculation patterns in 26 adult patients with infective endocarditis. Abnormal patterns were found in 13 patients (50%). Enlargement of capillary loops was never observed. Significant correlations were found between the number of capillary abnormalities and both systemic involvement (cutaneous vasculitis, arthritis, splenomegaly and/or glomerulonephritis) and immunological disturbances (circulating immune complexes, rheumatoid factor and/or hypocomplementemia) (p = 0.02 and 0.003, respectively). Capillary abnormalities were significantly reduced in 14 patients studied 4 to 48 months after endocarditis was cured. However, due to the lack of specificity, nailfold capillary microscopy cannot be regarded as a useful tool for the diagnosis of infective endocarditis. Connective tissue disorders are not the sole diagnosis to be considered in patients with abnormal nailfold capillary microcirculation patterns.

Adolescent↗

PubMed1989

[Disorders of microcirculation and myocardial function in primary pulmonary hypertension and Eisenmenger's syndrome].

Bulboangioscopy, aggregate state of the blood, ultrastructural examination of the microcirculatory bed of the skin, ultrasonic examination of the heart revealed that patients with primary pulmonary hypertension and Eisenmenger's syndrome did not show essential differences in the hemodynamics and blood microcirculation. In the treatment of these patients the stage of chronic circulatory insufficiency, vascular and intravascular disorders of the microcirculation should be considered.

Adolescent↗

PubMed1989

[A study using laser-Doppler velocimetry of modifications of the labyrinthine microcirculation induced by chemical and physical stimuli].

Vasomotor activity induced by physical and chemical stimuli in the cochlear microcirculation was evaluated by laser-doppler flowmetry. Cochlear flow changes were studied after pharmacological administration and noise exposure. The reaction of cochlear microcirculation after drug administration is similar to that observed in the brain. After phenylephrine injection the authors observed an increase of cochlear blood flow, contrary to that observed in the peripheral vessels. The authors studied the difference in time-activity and quantitative effect of several drugs commonly used in cochlear vascular diseases. Cochlear flow decrease after exposure to noise is proportional to the stimulus intensity and the exposure time.

Animals↗

PubMed1989

[Structure and functions of the human spleen: relationship between microcirculation and splenic functions].

Tissue blocks and vascular casts of the human spleen were studied by scanning electron microscopy. Splenic pulp was composed of white pulp packed with lymphocytes and red pulp which consisted of three dimensional reticular meshwork and splenic sinus. There were at least three types of microcirculation with different functions in the human spleen. First, open circulation in the red pulp is engaged in highly sensitive clearance of foreign materials in blood by numerous macrophages resided in splenic cord (culling function). It is also engaged in pitting function by narrow slits of the sinus. The second is the closed circulation occurred in the red pulp in the human spleen. It was represented as an arteriolar labyrinth whose endothelial cells connected with those of sinuses. Blood flow through this circulation is exposed to small number of macrophages in the sinus. It probably corresponds to the fast blood flow in the spleen. Third, microcirculation to the white pulp and marginal zone is engaged in phagocytosis of foreign materials in blood and carriage of their antigenic portions to lymphocytes in the white pulp. Therefore variation of the blood flow through their circulation may bring about a change of the splenic function. Relationship among blood flow, nerve stimulation and immune reaction was discussed.

Humans↗

PubMed1989

[The effect of dimethyl sulfoxide on the thromboelastographic indices and the microcirculation in patients with rheumatic diseases].

Using a blind method for assessing the results, a study was made of the effect of dimethylsulfoxide (DMSO) on fibrin formation and microcirculation in 42 patients with rheumatic diseases (rheumatoid arthritis, systemic scleroderma, Raynaud's syndrome). It has been shown that the therapeutic effect of DMSO in rheumatic diseases is determined to a definite degree by its normalizing action on fibrin formation and microcirculation.

Dimethyl Sulfoxide↗

PubMed1989

[Various aspects of the interrelations between blood phospholipids, blood coagulation and microcirculation in chronic bronchitis].

Studies of conjunctival microcirculation, thromboelastographic coagulation (as assessed by 8 parameters) and plasma phospholipid spectrum (with 8 fractions obtained), carried out in 136 patients with acute phases of chronic bronchitis, have demonstrated considerable disorders of microcirculation, hypercoagulation and shifts of blood phospholipid spectrum. Marked perivascular disorders were matched by increased levels of plasma lysophosphatidylcholines, which promote increased capillary permeability. Intravascular changes (erythrocyte aggregation and sludging, intermittent flow and stasis of blood) were accompanied by established hypercoagulation and increased phosphatidylethanolamines, producing a coagulating effect. A drop in plasma phosphatidylcholines is a symptom of disrupted synthesis of this phospholipid class in the lungs, and a disorder of pulmonary surfactant structure and function. The level of phosphatidylserins, conducive to histamine release by mast cells, rose in patients with the bronchospastic syndrome. Shifts in other phospholipid fractions, typical for different types and stages of chronic bronchitis, have also been demonstrated. Basically, the magnitude of shifts was greater prior to treatment in the majority of parameters.

Adolescent↗

PubMed1989

Mechanical hemolysis of cross-bonded red cells in the microcirculation.

In favic crises the effective surface area of red cells is reduced by a mechanism called membrane cross bonding (Fischer et al., Brit. J. Haematol. 59, 159, 1985). In these crises massive intravascular hemolysis is observed the cause of which is unknown. One possibility is mechanical hemolysis of cross-bonded red cells that cannot negotiate the microcirculation due to their decreased effective surface area. To investigate this possibility critical phenomena of red cell behavior in the microcirculation were studied using Laplace's law. In model calculations an idealized vessel geometry was used: a funnel in which the angle of the conical part and the radius of the cylindrical part were varied. A map of these two parameters was established showing where red cells either enter the funnel or get stuck and where they would hemolyse under a pressure difference of 3 mm Hg. Adopting a teleological point of view it was assumed that red cell and vessel geometry are mutually adapted. Based on this assumption those combinations of the two parameters cone angle and radius were found that allow the passage of the complete population of normal red cells without hemolysis. Assuming a reduction in red cell surface area similar to that observed in favic crises it was found that only a small portion of the population would hemolyse. Therefore, mechanical hemolysis may not suffice to explain the observed intravascular hemolysis.

Capillary Resistance↗

PubMed1989

[Status of cervical microcirculation in patients with myoma].

A study of cervical microcirculation demonstrated an essential impairment of capillary circulation in 104 patients with uterine myomas. Reconstructive plastic operations, sparing the uterus, contribute to the recovery of disturbed regional microcirculation and are justified pathogenetically.

Capillaries↗

PubMedDate not supplied

[Effect of hyperoxia on systemic hemodynamics, microcirculation, and oxygen regimen in rats in replacement of massive blood loss by albumin].

Experiments were conducted on rats to study systemic hemodynamics, microcirculation, and oxygen regimen in the organism in replacement of massive blood loss with albumin solution in normo- and hyperoxia. The results suggest that in breathing oxygen conditions are created in the organism for fuller realization of the mechanism of compensatory increase of the minute circulation volume in replacement of blood loss by a blood substitute, as a result of which total oxygen consumption increases and microcirculation is restored more adequately.

Albumins↗