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PubMed2003

[Microcirculation in hypertension].

Changes of microcirculatory vascular bed play important role in pathogenesis of essential hypertension. All components of the system of microcirculation including vessels and circulating blood are involved into pathological process. Resistance to blood flow is mostly formed in this system. Resistance depends on length, diameter of microvessels and viscosity of blood. In the process of the disease development the following signs of remodeling at the level of microcirculation emerge: decrease of density of vasculature, modification of the media/lumen ratio, increase of blood viscosity, slowing of angiogenesis, impairment of endothelial function. These phenomena can be both cause and consequence of hypertensive disease. Their heterogeneity depends on a variety of factors (duration, stage of the disease, etc.). It seems feasible to differentiate therapy in accordance with character and severity of changes in the system of microcirculation.

Animals↗

PubMed2003

[The effects of ginaton on cochlear microcirculation].

OBJECTIVE: This study was undertaken to investigate the effects of Ginaton, a kind of extract of gingko biloba with vasoactive, on cochlear blood flow, and to provide the experimental basis for the clinical drug usage. METHOD: Ninety-six guinea pigs were divided into two groups at random, 56 for intravenous infusion (i.v.) group, and 40 for round window membrane (RWM) application group. According to the preliminary results, i.v. group had five subgroups: control, 2.8 mg/kg, 3.5 mg/kg, 3.85 mg/kg, 4.2 mg/kg. RWM group had four sub-groups: control, 3.5 g/L, 0.35 g/L, 0.035 g/L. Ginaton and vehicle were infused through the cervical vein by micropump in 5 minutes. In RWM group, 2 microliters vehicle were dropped into RWM. Cochlear microcirculation was monitored by laser doppler flowmeter (LDF), and mean arterial blood pressure (MABP), which transferred by force transducers and preamplifier, were simultaneously recorded at the computer. RESULT: Cochlear blood flow (CBF) decreased 4.95% and CMBC decreased 6.32% in 3.5 g/L RWM group, and in 0.35 g/L RWM group, these two figures decreased individually 4.75%, 7.61%. In control and 2.8 mg/kg group cochlear microcirculation and MABP had no significant changes. In other i.v. groups, CBF increased 4.53%, 5.21%, 6.65% after 3.5 mg/kg, 3.85 mg/kg, 4.2 mg/kg drugs had been infused, and dosage-effect relation existed. Only in 3.85 mg/kg group, MABP decreased 8.69%. CONCLUSION: Ginaton could improve CBF in a limited dosage range, and this increase showed dose-dependent relation. The mechanism that Ginaton affected the cochlear microcirculation was different because of the way of drug usage.

Administration, Topical↗

PubMed1992

[Physiopathology of venous stasis at the microcirculation level].

The division of the venous circulation in to two sectors, one constituted by the superficial and deep venous trunks (macrocirculation) and the other by the capillaries and precapillary venules (microcirculation), is surely schematical but aids the comprehension of many hemodynamic effects connected to hampered venous return and to the incompetence of the valvular devices. In fact many of the effects of stasis and venous hypertension (oedema, red cell diapedesis, skin dystrophies) cannot be explained merely by hydraulic mechanisms but require a primary alteration of the microvascular wall associated with structural changes of the perivascular connective tissue. The alterations that occur in microcirculation are of the utmost importance in the formation of the venules ulcerations. The passage of fibrinogen through large pores in the venules of the patients affected by venous hypertension derived from venous insufficiency creates a pericapillary fibrin deposition that cannot be removed because of inadequate blood and tissue fibrinolysis. This accumulation acts as a barrier to the diffusion of oxygen and other nutrients, determining a stasis dermatitis that may lead to tissue necrosis and ulceration. The more precise knowledge of the phenomena connected with the venous stasis at the level of microcirculation (pericapillary fibrin deposition, endothelial ischemia, blocked lymphatic drainage) will not only allow a deeper comprehension of the clinical signs but hopefully will lead to a more effective treatment of the postphlebitic syndrome.

Humans↗

PubMed1992

[A microcirculation observation of the venous flaps].

This article presented the observation results of microcirculation of 84 island venous flaps performed on the ears of 42 rabbits. The survival rates of 5 groups divided by differently handling the vessel pedical of the flaps were: 1. maintaining artery and venous 90.36%. 2. maintaining distal and proximal venous 86.29%. 3. only maintaining proximal venous 75.71%. 4. only maintaining distal venous 28.75%. 5. ligating all vessels O(P < 0.01). The results of blood flow examined by laser Doppler and the number of micrangium counted by microcirculation microscope were decreasing upon the sequence of the above groups (P < 0.05). We found that there were exact microcirculation in the venous flaps of group 2, 3, 4, but the blood flow in these groups, especially the group 4, were slower than the group 1.

Animals↗

PubMed1992

[The effect of the individual biorhythm on conjunctival microcirculation in hypertension patients].

Deterioration of the condition in patients with arterial hypertension was found during the critical days of individual biorhythms and correlated with changes in the vascular and intravascular sector of the microcirculation. The peculiarities of individual biorhythms and state of microcirculation in patients with arterial hypertension allow to carry out timely and adequate drug correction of microcirculation disorders and central hemodynamics.

Adolescent↗

PubMed1998

[Disorders of hepatic microcirculation as early manifestation of rejection in clinical liver transplantation].

By means of thermodiffusion, monitoring of hepatic microcirculation was performed in 43 patients during the first week after liver transplantation. A significant decrease of liver perfusion was registered in 15 patients with early rejection. The disturbance of hepatic microcirculation preceded the increase of transaminases by 36 hours and the subsequent biopsy by 60 hours. Already 12 hours after the beginning of corticoid therapy liver perfusion started to recover. The quantification of hepatic microcirculation may facilitate faster diagnosis and treatment of early rejection following liver transplantation.

Graft Rejection↗

PubMed1992

Gastric microcirculation and acute gastric mucosal lesions in patients with hepatic cirrhosis.

We endoscopically investigated gastric microcirculation using a laser-Doppler flowmeter and acute gastric mucosal lesions (AGML) during a 3-year follow-up period in patients with hepatic cirrhosis. Gastric microcirculation tends to decrease in patients with hepatic cirrhosis, especially when gastric mucosal hemorrhage or mucosal petechiae are observed endoscopically. Total gastric resection was performed for gastric hemorrhage due to AGML in three patients, two of whom had good liver function--Child's grade A--and survived more than 5 years with a good quality of life, but one patient with Child's grade C experienced poor quality of life and died within 2 years after surgery. We conclude that decreased gastric microcirculation plays a role in the occurrence of AGML in patients with hepatic cirrhosis. Total gastric resection should be carefully considered for hemorrhagic gastritis in patients with Child's grade C hepatic cirrhosis.

Acute Disease↗

PubMed1992

[The effect of hyperbaric oxygenation on the secretory, motor function and microcirculation of the stomach and duodenal walls in patients with duodenal ulcers].

A total of 22 patients with duodenal ulcer were examined for secretory and motor functions, microcirculation of the gastroduodenal wall and changes in the stomach-duodenum interrelations under the influence of hyperbaric oxygenation. Of these, group I included 9 patients with active ulcer; group II 13 persons with a healing ulcer. To assess gastric and duodenal functions, use was made of pH-metry combined with the measurement of intraluminal pressure by "open catheters". Microcirculation of the gastroduodenal wall was estimated by the radiation method. The studies have shown that the patients with active ulcer treated by hyperbaric oxygenation manifested a decrease of motor activity of both stomach and duodenum, an improvement of acid-neutralizing function of the stomach, a reduction of the duration of duodenum acidification, a greater normalization of microcirculation in the duodenal wall than in the gastric wall. In the patients with healing ulcers, the duodenal motility returned to normal, the initially elevated gastric motility fell to normal, the acidification of the duodenal bulb declined, and the regional blood flow returned to normal. It may thus be concluded that the positive impact of hyperbaric oxygenation on gastroduodenal function was more pronounced in the patients with healing ulcers where a more considerable decrease of motor activity was not accompanied by duodenal motility suppression.

Adult↗

PubMed2004

[Effect of L-arginine on the changes of cerebral microcirculation following craniocerebral missile wound at early stage in cats].

OBJECTIVE: To study the alterations of cerebral microcirculation and the effect of L-Arginine after craniocerebral missile wound (CMW) at early stage in cats. METHODS: The CMW animal model in cat was constructed by Carey method. Altogether 12 mongrel cats with either sex were divided into the CMW group and the L-Arginine treatment group. The caliber (D), velocity (V) and blood flow (Q) of pial microvessels and pathological examination of brain tissue at 10 min before CMW and from 5 min to 5 h after CMW were evaluated in each group. RESULTS: 1. In CMW group, although the Da, Va and Qa of pial arteriole decreased from 5 to 20 minutes, Da and Qa elevated at 90 minutes after CMW. There were no significant changes in the Dv of pial venule, but the levels of Vv and Qv were lower at 5 min and 20 min after CMW. Qv increased from 45 min to 3 h after CMW. The pial venules were in congestion situation. 2. In the L-Arginine treatment group, the pial aterioles persistently dilated after CMW. The blood flow of pial aterioles increased at 20 min after CMW and the higher level lasted 5 h. Similarly, the dilation of pial venules was observed, and the blood flow increased at 20 min after the injury, followed by venules constriction temporarily. 3. Petechial hemorrhage, microthrombosis and nerve cell swelling were found in the cortex on the opposite side of the trauma area. The pathological changes were less severe in the L-Arginine treatment group than those in the CMW group. CONCLUSION: At the early stage after CMW, there are obstructions to cerebral microcirculation, which induce brain ischemia, hypoxia and secondary failure of cerebral function. The mechanism by which L-Arginine alleviates the impaired cerebral microcirculation may lie in the vascular activation of L-Arginine-NO system.

Animals↗

PubMed2004

[The effects of DPPH on cochlear microcirculation].

OBJECTIVE: To investigate the effects of free radical, 1, 1-Diphenyl-2-picylhydrazyl(DPPH), on cochlear blood flow. METHOD: Twenty guinea pigs were divided into 3 groups at random, 6 for control group, 6 for 1 mmol/L of DPPH group and 8 for 0.1 mmol/L of DPPH group. 2 microliters vehicle or drugs were dropped into round window membrane. Cochlear microcirculation was monitored by laser Doppler flowmeter and the mean arterial blood flow(MABP), which transferred by pressure conductor sensor and preamplifier, was simutaneously recorded by a computer. RESULT: MABP was stable throught the experiment. Cochlear blood flow increased 12.49% (P < 0.05) in 1 mmol/L group, and decreased 3.02% (P < 0.05). In control group cochlear microcirculation had no significant changes. CONCLUSION: DPPH has effects on cochlear microcirculation. The mechanism still need to be explored later.

Animals↗

PubMed2004

Basic factors determining the hemorheological disorders in the microcirculation.

Hemorheological properties and disorders are very specific in the microcirculation since blood is actually not a fluid in the capillaries and in the adjacent arterioles and venules. This is because almost half of the blood volume constitutes the red and white blood cells whose size is commensurable with the microvessels lumen. Based on perennial investigations we concluded that the advancement of blood in capillaries is primarily dependent on the "structure" of the flowing blood that determines the resistance to blood advancement in the microvessels rather than on the well-known hydrodynamic relationships characteristic for the larger blood vessels. Basing on the perennial research of the hemorheological disorders in the microvessels we succeeded to specify the principal factors determining the blood flow resistance in the microcirculation. These factors are as follows: the erythrocyte enhanced aggregability > their deformability > the local hematocrit > the blood plasma viscosity. Solution of these theoretical problems is very important for the theory and practical medicine, since the blood rheological disorders in the microcirculation play a significant role in development and outcome of such essential diseases as the cerebral and cardiac infarcts, the diabetus mellitus, arterial hypertension, tumor grow, and many others.

Capillaries↗

PubMed2004

Hemorheological disorders in the microcirculation following hemorrhage.

We analysed hemorheological disorders in the microcirculation of intestinal mesenterium of adult laboratory rats following massive exsanguinations when the mean arterial pressure dropped and then the hemorrhagic shock developed in the animals. The mesenteric microcirculation was analysed by the Texture Analysis System (Leitz, Wetzlar): (a) diameters of the afferent arterioles, capillaries, and efferent venules; (b) the blood flow velocity; (c) microvascular blood flow changes (during the RBC aggregation); (d) local microvascular hematocrit; and (e) the transformation of capillaries into plasmatic microvessels. During development of the hemorrhagic shock we found that the blood flow velocity decreased in all microvessels, there was an increased RBC aggregation which gradually enhanced in the mesenteric microvessels' lumen causing blood flow slowing down till appearance of stases. A part of the capillaries transformed into plasmatic vessels. Therefore the microcirculation demonstrated a significant decrease, this being related both to the lowered pressure gradient and to specific hemorheological disorders in the capillary networks.

Animals↗

PubMed1992

[Microcirculation during inhalation of 100% oxygen in rabbits].

Using a rabbit ear chamber (REC), the author compared the effect of air inhalation and that of 100% oxygen inhalation on microcirculation of rabbits. Eight rabbits, weighing 3-4 kg, were used for this study. After observing the microcirculation under air inhalation, the inspired gas was changed to 100% oxygen and the microcirculation was again observed. This procedure was repeated twice to confirm any changes that had been observed. No significant changes were observed in the blood pressure, heart rate and pulse pressure by inhaling either O2 concentration. During the inhalation of 100% oxygen, the diameter, blood-flow velocity and blood-flow rate of the arterioles were markedly reduced (P less than 0.01). All these parameters observed in the venules during air inhalation showed no significant differences compared with the values taken during 100% oxygen inhalation. This study using REC has shown that inhalation of 100% oxygen causes microcirculatory changes especially affecting the arterioles.

Administration, Inhalation↗

PubMed2005

Effect of inducible nitric oxide synthase on intestinal microcirculation in endotoxic shock.

To investigate the changes of intestinal microcirculation in endotoxic shock and the effect of inducible nitric oxide synthase (iNOS) on intestinal microcirculation, endotoxic shock was induced by intravenous injection of lipopolysaccharide (LPS) in mice. Mean arterial pressure (MAP) was monitored throughout the experimental procedure. The velocity and flux of red blood cell (RBC) in villus tip arteriole and capillaries were measured by FITC-labeled erythrocytes and intravital microscopy. The effect of iNOS was determined by targeted disruption of mice iNOS-gene and administration of S-methylthiourea sulfate (SMT), a selective inhibitor of iNOS, before LPS injection. No significant differences in MAP, RBC velocity and flux at baseline were found among wild type mice, SMT pretreated mice and iNOS-gene knockout mice. LPS induced a dramatic fall of MAP in wild type mice. The decrease of MAP was significantly restored in iNOS-gene knockout mice and in wild type mice received SMT before LPS injection. The velocity and flux of RBC in villus tip arteriole and capillaries decreased markedly after LPS injection in wild type mice, while significantly higher velocity and flux of RBC were found in iNOS-gene knockout mice and SMT-pretreated mice both 60 and 120 min after LPS injection. The results demonstrate that iNOS plays an essential role in the intestinal microcirculation disturbance which occurs in endotoxic shock.

Animals↗

PubMedDate not supplied

[Fluorescence angiography of the anterior eye segment in the evaluation of impaired microcirculation within the diagnosis of severity of eye burns].

We used fluorescence angiography to study the vascular microcirculation in the anterior eye segment of 14 patients with severe eye bums. The severity of eye burns is not only related with an impaired blood circulation in the conjunctiva, it also depends on a microcirculation status of episcleral vessels. Different degrees of permeability of fluorescein through the conjunctival or episcleral vessels make it possible to specify circulation disorders in both cases. Whether the impaired microcirculation in the anterior eye segment is transient or not can be established through a second fluorescence angiography made during days 7-8 from the burn trauma. The severity of eye burn depends directly on the sizes of ischemic regions of the sclera.

Adult↗

PubMedDate not supplied

[The diagnosis and correction of impairments of microcirculation, central hemodynamics, and oxygen status in children with traumatic shock].

The paper presents the results of studies of microcirculation, central hemodynamics, and oxygen status in 120 children aged 2-14 years who had traumatic shock of various etiology (40 with burn injury, 50 with mixed injury, and 30 with brain injury). The following studies were used: biomicroscopy of conjunctival microvessels with photo recording and processing on a computer; central hemodynamic monitoring; studies of a thromboelastogram, acid-alkali balance, and blood gases. The authors found the previously unknown parallels of the impairments of microcirculation, the severity of traumatic injury, and the parameters of central hemodynamics, and oxygen status in the patient. Traumatic shock was characterized by spastic impairments of all the components (perivascular, vascular, and intravascular) of microcirculation progressing to spastic-and-atonic ones. The degree of microcirculatory disorders depended on the severity of shock and the nature of injury. The criteria for compensation and decompensation in the microcirculatory module were defined. The routine infusion therapy initiated in the compensation period promotes to a significant alleviation of microcirculatory disorders; however, the mentioned shifts long persist. In this connection, a package of additional measures (infucol GEC solutions, disaggregatory, antihypoxic, and antioxidant agents, and coenzymes of vitamins) has been developed.

Acid-Base Equilibrium↗

PubMed2005

Early evaluation of coronary microcirculation by echocardiography with contrast medium in patients with acute myocardial infarction treated with primary percutaneous transluminal coronary angioplasty.

AIM: In about 30% of patients with ST elevated myocardial infarction (STEMI), in which a TIMI 3 flow is obtained in the infarct related artery (IRA) after primary percutaneous transluminal coronary angioplasty (PTCA), it's not possible to obtain a good perfusion of coronary microcirculation (no reflow). Aim of the study is to estimate the prognostic value of microcirculation study by echocardiography with contrast medium (MCE) within 48 h from procedure and to point out if there're clinical or procedural factors correlated with no reflow. METHODS: From February 2002 to June 2003 we have analyzed the integrity of microcirculation by MCE in patients with STEMI treated with PTCA. We have included in this study 62 patients with anterior myocardial infarction (MI) (first event), within 12 h from symptoms onset, with great echocardiographic window and TIMI 3 flow in the IRA after PTCA, excluding shock. We have obtained the evaluation of myocardial perfusion by MCE within 48 h from the treatment. We have used Sonovue as contrast medium, infused through peripheral vein. In each patient we have measured: perfusion index (PI) (sum of single segments scores divided by total number of myocardial segments) and regional perfusion index (RPI) (number of normal perfused segments between the diskinetic ones divided by diskinetic segments). RPI varies from 0 to 1: when >0.5 it has been considered index of good perfusion. Ejection fraction (EF) and wall motion score index (WMSI) have been calculated within 48 h and at 6 weeks follow up. ST resolution (STR) has been evaluated at 90 min from procedure and it was considered significant when >70%. RESULTS: Patients have been divided into 2 groups by myocardial perfusion: group R (33 patients with RPI>0.5) and group NR (29 patients with RPI =/<0.5). The 2 groups were similar for age (group R: mean age 61 years old; group NR: mean age 64 years old, P=n.s.), glycoprotein inhibitors use (group R 90%, group NR 97%, P=n.s.), diabetes (group R 12%, group NR 17%, P=n.s.), hypertension (group R 22%, group NR 23%, P=n.s.), incomplete revascularization (group R 12%, group NR 10%, P=n.s.). Group NR has shown a major women percentage (33%) than group R (9%) P=0.026. In group R we have appreciated a trend to a major percentage of TIMI 2-3 flow preprocedure (66% vs 36%, P=n.s.), a shorter ischemic time (209 min vs 258 min, P=n.s.) and a major STR at 90 min (72% vs 53%, P=n.s.), not statistically significant. Echocardiographic analysis and MCE show a better myocardial perfusion in group R (RPI 0.7 vs 0.14 and PI 0.96 vs 0.86, P<0.0001); better left ventricular kinetics at 6 weeks follow up (EF 54.2% vs 50.8%, P=n.s. and WMSI 1.07 vs 1.2, P=0.014) but not in the acute phase (EF 46.8 vs 42.9 and WMSI 1.3 vs 1.34, P=n.s.) 30 days mortality is similar in the 2 groups (both 3%). CONCLUSIONS: Myocardial perfusion evaluation correlates with left ventricular contractility measured at 6 weeks from acute MI, but doesn't correlate with contractility in the acute phase or 30 days mortality.

Angioplasty, Balloon, Coronary↗

PubMed2005

[Intraoperative laser doppler flowmetry of the tissue microcirculation of extraperitoneal transplanted omental flaps on dogs].

The aim of this study was to develop a new method to check of the viability of an extraabdominally transplanted omental flap. We performed free omental transplantation to the left lateral neck region in the frame of a formerly published new esophageal resection series on 5 dogs. Intraoperative laser Doppler flowmetry was performed, before and after isolation, after transplantation, and 14 days after the operation. From the 5 transplanted flaps, 4 survived the transplantation. The flap microcirculation deteriorated immediately after the transplantation, but at the time of re-operation the measurements showed similar microcirculation as control tissues, which proves the viability of the transplanted flaps. In our opinion, in dogs for the intraoperative monitoring of viability and microcirculation of free transplanted omental flaps, laser Doppler flowmetry is a feasible method.

Animals↗