Morphofunctional characteristics of the conjunctival microcirculation of students of different regions of the world

By means of vital microscopy, the conjunctival microcirculation has been estimated in students from various regions of the world depending on duration of the time of their life in the USSR. Adaptive rearrangements of the conjunctival microcirculation of the eye ball have been revealed in various time of adaptation. Integral estimation of the conjunctival microcirculation has demonstrated that at initial phase of adaptation synchronization in the work of separate links of the microcirculatory bed is observed. These changes can be interpreted as strain of the compensatory mechanisms. In two years of study, certain stabilization of the microcirculation system activity is observed in the foreign students; this can be considered as the phase of stable adaptation. In the students arrived from hot regions of the world, pigmentation in the eye ball conjunctiva has been revealed. By means of the correlative analysis it has been demonstrated that the pigmentation influences the most labile parts of the microcirculatory bed-capillaries and venules. Pigmentation is usually regarded as a pathological sign peculiar for some diseases. Our investigations have demonstrated that pigmentation should be interpreted carefully and the place of residence of the students investigated should be taken into account, since pigmentation can be the result of elevated solar radiation, specific for hot regions of the Earth.     

Age-related differences in the dynamics of the skin blood flow oscillations during postocclusive reactive hyperemia

Age-related changes in peripheral microcirculation were studied using laser Doppler flowmetry in 60 apparently healthy subjects. The response of microcirculation to short-term ischemia was studied using the occlusion test. Changes in the amplitude of the peripheral blood flow oscillations were determined using time-amplitude analysis based on continuous adaptive wavelet filtration. The oscillation amplitude in the frequency range of the heart rate was found to reach the maximum with a delay after the removal of the occlusion, whereas in the range of the respiratory rhythm, no delay was observed. The hyperemic response to short-term ischemia is assumed to develop under the predominant influence of the arterial-arteriolar component, whereas the dynamics of amplitude oscillations in the range of the respiratory rhythm is a result of the devastation of the venular component after removal of occlusion. In response to short-term ischemia, the maximum oscillation amplitudes of myogenic, neurogenic, and endothelial rhythms decreased with age, which demonstrates the restriction of the regulatory control of the peripheral blood flow by the corresponding systems.     

The arrangement of endoplasmic reticulum and proteosynthesis in spinal ganglia neurons of dog after ischemia

The authors studied ultrastructural and biochemical changes in spinal ganglia neurons of dogs after ischemia. Partial spinal cord ischemia was induced by occlusion of the abdominal aorta just below the renal arteries and the arterial blood pressure was registered above and below the occlusion. - In the course of 2-4 hours' ischemia the amount of free ribosomes increased. In some cases the formation of filamentous material or tubular structures inside the cisterns of endoplasmic reticulum was apparent. The proteosynthesis declined. Incorporation of 14C - leucine into the spinal ganglion was 50% as compared to the control animals. The morphological and biochemical changes were more pronounced after 4 h ischemia.     

Quantitative changes in liver dehydrogenase activity during temporary ischemia of the extremities and in the postischemic period

Experimental temporary occlusion of the dog hind limbs was produced. Histoenzymological changes in the liver induced by the temporary ischemia of the limbs and by ischemia with a 2-hour revascularization were subjected to comparative histophotometric examination. The data obtained indicate an appreciable rise in the enzymatic activity of hepatocytes at the early stages of experiments and increasing reduction in metabolic processes at the later stages. A substantial decrease was noted in the activity of the liver enzymes under study, with that decrease being especially pronounced at the later times in experiments with limb revascularization, which is accounted for by a far greater release to the bloodstream of metabolic products from the ischemized limbs.     

Comparison of OPS imaging and conventional capillary microscopy to study the human microcirculation.

Orthogonal polarization spectral (OPS) imaging is a new clinical technique for observation of the microcirculation of organ surfaces. For validation purposes, we compared OPS images of the nailfold skin with those obtained from conventional capillary microscopy at rest and during venous occlusion in 10 male volunteers. These images were computer analyzed to provide red blood cell velocity and capillary diameters of the same nailfold capillaries at rest and during venous occlusion. Results showed that OPS images provided similar values for red blood cell velocity and capillary diameter as those obtained from capillary microscopy images. OPS imaging, however, provided significantly better image quality, as shown by comparison of image contrast between OPS imaging and capillary microscopy. This made image analysis better and easier to perform. It is anticipated, therefore, that OPS imaging will become a new and powerful technique in the study of the human microcirculation in vivo because it can be used on human internal organs.     

The functional state of microcirculation and autonomic regulation in young subjects with different levels of subjectively experienced psychological stress

A comprehensive comparative analysis of hemodynamics, microcirculation (the method of laser Doppler flowmetry with an occlusion test and the optical tissue oxymetry), blood circulation neurohumoral regulation (analysis of heart rate variability, HRV) in apparently healthy young subjects with different levels of subjectively experienced emotional stress has been performed. Depending on the degree of everyday stress (acute and/or chronic), the character of the autonomic regulation of blood circulation, as well as the state of the microcirculation and its regulation substantially vary. Moderate stress is accompanied by coactivation of sympathetic-parasympathetic regulatory mechanisms with augmented HRV baroreflex regulation circuits, which compensates for hemodynamic changes and is not accompanied by hypotensive reactions. An increase in the activity of neurogenic and myogenic tones of microhemodynamics in the subjects with moderate stress, which determines a high probability of blood shunting in tested tissue and decrease in relative oxygen extraction, has been discovered. Moderate levels of stress are also associated with an increase in the latency of postocclusive vasoreactive hyperemia, which is considered to be an early sign of the endothelium-mediated dysfunction of microcirculation.     

康柏西普联合视网膜激光光凝对缺血型视网膜中央静脉阻塞患者球结膜微循环指标和血管内皮功能的影响

摘要 目的：探讨康柏西普联合视网膜激光光凝对缺血型视网膜中央静脉阻塞患者球结膜微循环指标和血管内皮功能的影响。方法：选取2016年8月到2019年9月我院收治的缺血型CRVO患者90例,按信封抽签法分为对照组（n=45,视网膜激光光凝治疗）和研究组（n=45,视网膜激光光凝联合康柏西普治疗）,比较两组患者黄斑中心视网膜厚度(CMT)、球结膜微循环指标、最佳矫正视力(BCVA)、疗效、血清血管内皮生长因子（VEGF）、内皮素-1（ET-1）、一氧化氮（NO）水平以及不良反应。结果：治疗后6个月研究组临床总有效率高于对照组（P<0.05）。治疗后6个月,研究组的BCVA升高程度以及细动脉管径、细静脉管径扩大程度均大于对照组（P<0.05）,CMT以及红细胞聚集积分降低程度大于对照组（P<0.05）。治疗后3 d,研究组的VEGF、ET-1降低程度大于对照组（P<0.05）,NO升高程度大于对照组（P<0.05）。两组不良反应发生率对比未见差异（P>0.05）。结论：康柏西普联合视网膜激光光凝治疗缺血型CRVO疗效较好,可有效改善患者视力及球结膜微循环,同时还可改善血管内皮功能,安全可靠。     

Characteristics of the microcirculation and blood rheology in arterial and venous forms of mesenteric vascular occlusion

The functional properties of microcirculation and rheology of blood were studied in dogs subjected to arterial and venous occlusion of mesenteric vessels (cranial mesenteric artery and cranial mesenteric vein). It was found that a local alterations of microvascular bed of intestinal wall are quite different in case of arterial or venous occlusion. The degree of hemorheological and microvascular deviations is higher in case of acute venous thrombosis than during the acute occlusion of cranial mesenteric artery.     

Microvascular dilation in response to occlusion: a coordinating role for conducted vasomotor responses

In rat cremasteric microcirculation, mechanical occlusion of one branch of an arteriolar bifurcation causes an increase in flow and vasodilation of the unoccluded daughter branch. This dilation has been attributed to the operation of a shear stress-dependent mechanism in the microcirculation. Instead of or in addition to this, we hypothesized that the dilation observed during occlusion is the result of a conducted signal originating distal to the occlusion. To test this hypothesis, we blocked the ascending spread of conducted vasomotor responses by damaging the smooth muscle and endothelial cells in a 200-microm segment of second- or third-order arterioles. We found that a conduction blockade eliminated or diminished the occlusion-associated increase in flow through the unoccluded branch and abolished or strongly attenuated the vasodilatory response in both vessels at the branch. We also noted that vasodilations induced by ACh (10(-4) M, 0.6 s) spread to, but not beyond, the area of damage. Taken together, these data provide strong evidence that conducted vasomotor responses have an important role in coordinating blood flow in response to an arteriolar occlusion.     

Venoplasty of a chronic venous occlusion with ‘diathermy’ for cardiac device lead placement

Venous revascularization is an approach used in patients with total venous occlusion requiring venous access for cardiac device lead placement. Several percutaneous approaches to venous revascularization have been proposed. For the first time, we describe the case of a 69-year-old male with total venous occlusion who was successfully revascularized using a ‘diathermy’ technique.     

Effects of brovincamine on the stereological parameters of corticocerebral capillaries

A number of clinical studies in patients with cerebrovascular insufficiency or symptoms resulting from multiple cerebral infarctions have shown that brovincamine significantly reduces the number of ischaemic regions and the left/right asymmetry of blood flow to the hemispheres, and brings about general improvement of the microcirculation. An optical-electronic image analysis technique was used to investigate whether brovincamine (7.5 mg/kg/day orally for 4 weeks) had any effect on stereological parameters of the corticocerebral capillaries of 1-year-old and 3-year-old OFA rats (n = 20). The older group of rats was included since in man changes in capillary geometry are known to be one of the manifestations of aging. The results show that brovincamine significantly increases the efficiency of capillary clearance, which is accompanied by an increase in capillary length and capillary volume per unit volume of tissue, resulting in a shortening of the mean intercapillary diffusion paths, a rise in capillary density and an increase in capillary diffusion area. No significant difference was observable between young and old rats. The changes in both groups of animals took the same form. From the above findings it was concluded that brovincamine improves the corticocerebral microcirculation by virtue of its effect on capillary geometry.     

Blood vessels and nerve apparatus of the heart and small intestine during continuous experimental bypass shunting]

In 140 animals (mongrel dogs of different age and sex) by means of histological, neurohistological, histochemical, histoenzymatic and electron microscopic methods, character and dynamics in changes of nerve elements and blood vessels of the heart and the small intestine have been studied under the conditions of revascularization at aorto-coronary and aorto-mesenteric shunting. The changes revealed are mainly reactive in their character, perform defensive, compensatory-adaptive response of the organs to the orative trauma and to an adequate but slightly changed blood stream. The degree of acuteness and the time when these changes disappear depends on duration of postocclusive ischemia, on the organs' resistivity to its effect on the operative trauma. Operation of aorto-coronary and aorto-mesenteric shunting are rather effective and protect the vascular bed and the intramural nerve appratuses of the heart and the small intestine from severe destructive disorders developing as a result of occlusion in the arterial vessels.     

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.     

Cutaneous microcirculation in systemic sclerosis and response to intra-arterial reserpine.

The cutaneous microcirculation in the hand was measured in 23 patients with systemic sclerosis, 19 with Raynaud''s phenomenon and four without Raynaud''s phenomenon, and 20 controls. The patients with Raynaud''s phenomenon had a reduced basal blood flow and an exaggerated further reduction on local cold stimulation, though both were normal in patients without Raynaud''s phenomenon. Reflex-induced vascular changes by cold stimulation of the contralateral hand showed no differences between the three groups. The blood flows were similar in the affected skin of the anterior chest wall in four patients with systemic sclerosis and peripheral Raynaud''s phenomenon and matched controls. In the seven most severely affected patients 1 mg of intra-arterial reserpine produced a prompt improvement in the cutaneous microcirculation which usually lasted one to three weeks but occasionally much longer. By judicious use of repeated injection guided by measurements of the microcirculation it was possible to heal indolent ulcers of the fingers. The results indicate that vascular changes are common in systemic sclerosis but are not fundamental in the pathogenesis of the disease. More probably there is a general soft tissue abnormality that usually but not necessarily affects the vessels.     

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.     

Aging features in functioning of skin microvascular bed in humans

The state of skin microcirculation system has been studied in healthy volunteers aged from 20 to 77, using laser Doppler flowmetry. To reveal the reaction of microvascular bed in response to short-term ischemia, occlusive test has been carried out. During experiment the age-induced reduction of microcirculation index has been observed at rest. In response to stopping occlusion the 3.5--4-aliquot increase of microcirculation index has been revealed during reactive post-occlusive hyperemia in all age groups. The data obtained suggest maintenance of high reserve resources of skin microcirculation in ageing in response to ischemia.     

Changes in the blood microcirculation in the mouth mucosa in experimental stomatitis

Aphthous lesions in the oral mucosa (OM) were simulated in dog experiments by ligation of the common bile duct. In one of the experimental groups the beta-adrenoblocker propranolol was administered 30 min before surgery. Two hours after surgery the animals manifested changes in blood microcirculation of the OM. In animals treated with propranolol, the characteristics of blood microcirculation remained within normal. It is concluded that the development of aphthous lesions is preceded by functional disorders of blood microcirculation in the OM which are probably related to alterations in the neurovascular system.     

Focal topographic changes in inflammatory microcirculation associated with lymphocyte slowing and transmigration

Microcirculation is the primary mechanism for delivering lymphocytes to inflammatory tissues. Blood flow within microvessels ensures a supply of lymphocytes at the blood-endothelial interface. Whether the structure of the inflammatory microcirculation facilitates lymphocyte transmigration is less clear. To illuminate the microcirculatory changes associated with lymphocyte transmigration, we used intravital videomicroscopy to examine the dermal microcirculation after application of the epicutaneous antigen oxazolone. Intravascular injection of fluorescein-labeled dextran demonstrated focal topographic changes in the microcirculation. These focal changes had the appearance of loops or hairpin turns in the oxazolone-stimulated skin. Changes were maximal at 96 h and coincided with peak lymphocyte recruitment. To determine whether these changes were associated with lymphocyte transmigration, lymphocytes obtained from efferent lymph of draining lymph nodes at 96 h were fluorescently labeled and reinjected into inflammatory microcirculation. Epifuorescence intravital video microscopy demonstrated focal areas were associated with lymphocyte slowing and occasional transmigration. In contrast, focal loops and lymphocyte slowing were rarely observed in the contralateral control microcirculation. Results suggest that structural adaptations in inflammatory microcirculation represented by focal topographic changes may contribute to regulation of tissue entry by recirculating lymphocytes.     

Microcirculatory changes in the cheek pouch mucosa of hamsters in the dynamics of experimental traumatic shock]

Acute experiments conducted on hamsters demonstrated significant disturbances of the microcirculation in the mucosa of the cheek pouch during a severe traumatic shock after a standardized mechanical injury of the hip. All the animals died in the course of the first 24 hours after this trauma. If the animals died not earlier than in one hour after the trauma the microcirculation changes were distinctly phasic in character; particularly there was seen a phase of temporary relative adaptation and stabilization of the peripheral circulation, invariably followed by the phase of decompensation, the terminal phase and death. In cases with a rapid lethal issue in the course of one hour no distinct phasic character of the microcirculation changes was observed, but there was a more or less rapid aggravation of all he indices. In difference from the majority of other investigators, no marked intravascular erythrocyte aggregation was seen by the authors in the experiments described.     

Autologous transfusion of erythrocytes with high or low concentration of 2,3-diphosphoglycerate. Survival rate and time and hemoglobin-oxygen affinity]

1. In human erythrocytes the 2.3 DPG concentration was increased three to fourfold of the norm as IPP re-suspension by an incubation time of four hours at 37 degrees C or as ACD-AG blood was lowered below 20% of the norm respectively. After an autologous transfusion the 24 hours' surviving rate and the apparent half survival time of cells as well as the affinity of haemoglobin to oxygen in the total blood were measured. 2. The 24 hours' surviving rate for fresh erythrocytes with increased 2.3 DPG and ATP concentration amounts to 73% and the apparent half survival time amounts to 6 days. If erythrocytes are stored for four weeks as IPP resuspension at 4 degrees C, the 24 hours' surviving rate is 59%. Erythrocytes from fresh ACD-AG blood with lowered 2.3 DPG and a normal ATP concentration have a 24 hours' surviving time of 85% and an apparent half survival time of 24 days. 3. After autologous transfusion of 400 ml of erythrocytes with increased 2.3 DPG concentration the P50 value of the total blood will increase by 3 mm of Hg, after administering 400 ml of erythrocytes with lowered 2.3 DPG concentration it will fall by 1.8 mm of Hg. 4. The findings are discussed in connection with the significance of the changes of affinity of haemoglobin to oxygen produced by 2.3 DPG for the oxygen supply of tissues and under the aspect of using stored blood with increased 2.3 DPG concentration for practical purposes.