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Results for “Microcirculation”

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At least 109 records · Page 6Linked to original sources

PubMed1999

In vivo evaluation of platelet-endothelial interactions in retinal microcirculation of rats.

PURPOSE: This study was designed to develop a new method to evaluate the dynamics of platelets in the retinal microcirculation in vivo and to investigate quantitatively the platelet-endothelial interactions in rat retina with the use of this system. METHODS: Isolated platelet samples were labeled with carboxyfluorescein diacetate succinimidyl ester. After intravenous administration, platelet behavior in the retinal microcirculation was evaluated with a scanning laser ophthalmoscope. The images were recorded on S-VHS videotape and analyzed with a computer-assisted image analysis system. The platelet- endothelial interactions in the retinal microcirculation were also investigated with the use of lipopolysaccharide-stimulated endothelium or platelets activated with thrombin. RESULTS: Fluorescent platelets were recognized as distinct dots in the retinal microcirculation and could be traced frame by frame. The velocity of platelets in the retinal arteries, capillaries, and veins was 26.1+/-6.4, 1.6+/-0.4, and 19.9+/-8.2 mm/sec, respectively. In control rats, even the activated platelets showed minimal interaction with retinal endothelial cells. In contrast, stimulated retinal endothelium showed active platelet- endothelial interactions; many platelets were observed rolling and adhering along the major retinal veins. The interactions between platelets and stimulated endothelial cells were substantially inhibited with the injection of P-selectin monoclonal antibody. CONCLUSIONS: The present study demonstrated a new method to visualize platelet behavior in the retinal microcirculation in vivo. This method will allow quantitative evaluation of platelet dynamics and platelet- endothelial interactions in retinal pathologic conditions.

Animals↗

PubMed1999

Impaired skin microcirculation and blood rheology in patients with monoclonal gammapathy.

Hemorheological disturbances in patients with monoclonal gammapathies are widely known, but there is little information about microcirculation in these patients. The following study was performed to examine skin microcirculation and its relationship with blood rheology. We analysed both haematological and hemorheological parameters (blood and plasma viscosity, aggregation index and filterability of 1 ml of whole blood) and skin microcirculation in 46 patients with monoclonal gammapathy and 22 healthy controls. Microcirculation on dorsal aspect of the hand was examined with laser Doppler flowmeter. We measured resting flow and biological zero and maximal flow during postischemic hyperaemic reaction after one minute occlusion on the arm. The same parameters were estimated for CMBC (concentration of moving blood cells). Patients with monoclonal gammapathy are characterised by statistically higher whole blood and plasma viscosities and other hemorheological parameters and disturbed skin microcirculation expressed as statistically significant lower resting flux and impaired reaction for temporary occlusion.

Adult↗

PubMed1999

Role of gastric microcirculation in the gastroprotection by glucocorticoids released during water-restraint stress in rats.

Our previous investigations demonstrated that glucocorticoids released in response to stress protect gastric mucosa against stress-induced ulceration. This study was designed to determine whether gastric microcirculation is involved in the mechanism of gastroprotective glucocorticoid action. For this we evaluated the effects of deficiency of glucocorticoid production during 3 hr water-restraint stress and corticosterone replacement on the stress-induced gastric erosions, gastric microcirculation and arterial pressure in rats. The stress was produced in awake rats and gastric microcirculation and arterial pressure were evaluated in animals anesthetized in 3 hr after the onset of water-restraint stress. An in vivo microscopy technique for the direct visualization of gastric microcirculation was employed. The gastric submucosal and the superficial mucosal microvessels were monitored on television screen through a microscope and the pictures were stored by microfilming for the analysis of red blood cell velocity and vessel diameter. Gastric microcirculation was estimated on the base of both the volume blood flow velocity in submucosal microvessels and the diameter of superficial mucosal venous microvessels. Gastric erosions were quantitated by measuring the area of damage. Plasma corticosterone levels were also measured after 3 hr stress by fluorometry. Water-restraint stress induced an increase in corticosterone level, an appearance of gastric erosions, a decrease in volume blood flow velocity of submucosal microvessels, a dilatation of superficial mucosal microvessels, a decrease in arterial pressure. The deficiency of glucocorticoid production during water-restraint stress promoted the stress-induced gastric ulceration, a dilatation of mucosal microvessels, a decrease of blood flow velocity in submucosal microvessels and of arterial pressure. Corticosterone replacement eliminated the effects of deficiency of glucocorticoid production on all of the parameters under study. Thus, the stress-induced corticosterone rise decreased gastric ulceration, restricted both the reduction of blood flow velocity in submucosal microvessels and a dilatation of superficial mucosal venous microvessels during water-restraint stress. These data suggest that the gastroprotective action of glucocorticoids during stress may be provided by the maintenance of gastric blood flow.

Animals↗

PubMed2000

PKC-beta inhibitor (LY333531) attenuates leukocyte entrapment in retinal microcirculation of diabetic rats.

PURPOSE: The activity of protein kinase C (PKC), preferentially beta isoform of PKC, has been shown to be elevated in the diabetic retina. Recently, LY333531, a specific inhibitor of PKC-beta, has been reported to improve the decrease of retinal blood flow in early diabetes. Increased leukocyte entrapment has been suggested to be involved in blood flow disturbances in the early diabetic retina. This study was designed quantitatively to evaluate leukocyte entrapment in the retinal microcirculation of diabetic rats and the effect of LY333531 on leukocyte entrapment. METHODS: Diabetes was induced in male Long-Evans rats by intraperitoneal injection of streptozotocin (60 mg/kg). LY333531 (0.1, 1.0, or 10.0 mg/kg/d) was administered orally during a 4-week diabetic period. Leukocyte entrapment in the retinal microcirculation was quantitatively evaluated in vivo with acridine orange digital fluorography. RESULTS: The number of leukocytes trapped in the retinal microcirculation of diabetic rats (mean +/- SEM; 14.3 +/- 1.3 cells/mm2) was significantly increased, compared with nondiabetic control rats (7.5 +/- 0.3 cells/mm2; P < 0.0001). Oral administration of LY333531 significantly decreased the number of leukocytes trapped in the retinal microcirculation of diabetic rats (10.9 +/- 0.6, 11.3 +/- 0.7, and 10.4 +/- 0.4 cells/mm2 with LY333531 0.1, 1.0, and 10.0 mg/kg/d, respectively; P < 0.05). CONCLUSIONS: Treatment with LY333531 attenuated the increase of leukocyte entrapment in the retinal microcirculation during the period of early diabetes. This effect may contribute to the improvement of abnormal retinal blood flow in early diabetes with LY333531. LY333531 might have a therapeutic efficacy in preventing microcirculatory flow disturbances by trapped leukocytes in the early diabetic retina.

Acridine Orange↗

PubMed2001

Assessing the microcirculation in a burn wound by use of OPS imaging.

We report on the use of OPS imaging to visualize the microcirculation in a burn wound. This novel technique produces high quality images of the microcirculation and quantitative analysis of functional capillary density (FCD) was possible. FCD measured at day 3 following the injury was 11.2 +/- 4.6 (n/mm superset2; mean +/- SEM). During the initial phase of healing microcirculatory changes were characterized by a moderate but steady increase of FCD, which showed marked increase beginning from day 12 following the burn (16.6 +/- 6.9). Maximal FCD measured at day 23 (48.2 +/- 19.7) decreased from this point in time to finally reach 25.2 +/- 10.3 n/mm superset2 at the end of observation. OPS imaging allows for direct in vivo visualization and quantification of the microcirculation in burned skin. Our results of the use of OPS imaging in assessing the microcirculation in a burn wound appear promising, and we hope that this novel technique will allow to improve the knowledge of the dynamics of the microcirculation in the pathophysiology of thermal injury.

Adult↗

PubMed1997

[The mechanisms of antioxidantenzyme against inflammatory lesion in animal oral mucosa. I. An investigation on microcirculation in oral mucosa].

A technique of vital microcirculation observation and electron microscope were used to study the microcirculation in hamster cheek pouch, in which an acute inflammatory lesion was induced by oxygen free radicals (OFR). At the same time, the effect of superoxide dismutase (SOD) on the microcirculation was assessed. The results showed that in the model group the microcirculation disturbance in the cheek pouch was very serious. However, in the SOD group the microcirculation was almost unchangable.

Animals↗

PubMed2001

In vivo assessment of colon microcirculation: comparison of the new OPS imaging technique with intravital microscopy.

BACKGROUND: The Orthogonal Polarization Spectral (OPS) imaging technique has been introduced for in vivo assessment of microcirculation in humans. Unclear remains, whether the new technique would allow for accurate investigations of the colon microcirculation with respect to the unique conditions of the microvasculature in that particular tissue. Therefore, the aim of this study was to validate the new technique against intravital fluorescence microscopy (IFM) for the visualization of colon microcirculation in a murine model of inflammatory bowel disease (IBD). METHOD: IBD was induced in Balb/c mice by dextran sulfate sodium (DSS), controls received normal water. In each animal, both the CYTO-SCAN A/R and IFM were used to image the microcirculation (n = 7 in each group). Postcapillary venular diameter, venular red blood cell velocity (RBC-V) and functional capillary density (FCD) were analyzed on the colon muscularis and mucosa and compared to each other using linear regression analysis and Bland-Altman plots. RESULTS: All parameters correlated significantly between the both methods. The venular diameters and the RBC-V were significantly different between control and colitis group in contrast to FCD; these results were present while using both methods. CONCLUSION: Our study demonstrates that the new technique for visualization of microcirculation without use of fluorescent dyes, the OPS-imaging, allows for quantitative measurement of the key microcirculatory parameters of the mouse colon.

Animals↗

PubMed2002

[Effect of microcirculation on the morphofunctional state of skin].

Peculiarities of the morphofunctional state of skin, to a large extent, depend on the state of microcirculation. As the skin nutrition is provided by the microvessels, the question arises if the disturbances in microcirculation affect the parametres of the morphofunctional state of the skin. The main clinical investigations on microcirculation are represented in this review: the influences of systemic and local microcirculatory disturbances on the physiological parameters of skin, as well as the age changes of microcirculation and their influences on the dermatosis have been elucidated. The main questions on physiology and pathology of the skin microcirculation and methods of their study have been described.

Aging↗

PubMedDate not supplied

[Fluorescent angiographic evaluation of the iris microcirculation in cataract extraction by Nd:YAG laser with wavelength of 1.44 mcm].

The purpose of the present study is to evaluate the iridial microcirculation by fluorescent iridial angiography after laser cataract extraction by using a new extraction device, i.e. "RAKOT", based on the Nd:YAG-laser with wave length of 1.44 mcm. 25 eyes (21 patients) aged 71 to 87 with mature senile cataract were examined. The method of laser cataract extraction was used in 14 cases. These eyes made up the main examination group. As for the controls (11 eyes), the manual technic of cataract extraction was used for them. The results in the main group show that the degree of the response of the iridial microvessels to surgery is insignificant and the microcirculation restores completely in 1.5-2 months after surgery provided there are no initial pathological changes in the iridial microcirculation (3 eyes). A short-time intensification of permeability of the iridial microcirculation is possible in eyes with a pronounced initial pathology in the iris (11 cases), however it restores to the original level during 3-3.5 months after surgery. The iridial microcirculation restores in the controls during 3 months after surgery. The described data demonstrate that the laser cataract extraction does not lead to pronounced iridial vascular disorders. A comparison with the controls is indicative of a lower trauma in case of laser method versus the manual technic of lens extraction.

Age Factors↗

PubMed2003

[Effect of shenfu injection on microcirculation].

This study was aimed to assess the effect of Shenfu injection on different circulation state. Using a microcirculation microscope system, we observed mice's auricle micro-artery diameter, density of capillary, blood velocity in different circulation state (i.e. normal state, epinephrine or endotoxin induced microcirculation disturbance state) after administering Shenfu injection into their caudal vein, and we compared the Shenfu group with Shenmai group and Dexamethasone group. The results showed that Shenfu injection causes the auricle microartery diameter to enlarge and the density of capillary and blood velocity to increase in different microcirculation state, and such effect is especially notable on the epinephrine induced microcirculation disturbance group and endotoxin induced microcirculation disturbance group; the effect of Shenfu injection is stronger than that of Shenmai injection and similar to Dexamethasone injection. In addition, Shenfu injection was shown to have remarkable effect on resisting the lowering of limb temperature when the mice are attacked by endotoxin.

Animals↗

PubMed2003

Expression of platelet endothelial cell adhesion molecule-1 between pancreatic microcirculation and peripheral circulation in rats with acute edematous pancreatitis.

OBJECTIVE: To study the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in rats with acute edematous pancreatitis (AEP). METHODS: The model of AEP was established with 50 Wistar rats, and the changes of PECAM-1 expression on PMNs from the splenic vein and inferior vena cava were determined by flow cytometry. RESULTS: PECAM-1 expression on PMNs showed no significant difference between pancreatic microcirculation and peripheral circulation at AEP2h and AEP4h time points. From the AEP4h to the AEP8h time point, PECAM-1 expression in peripheral circulation was up-regulated, but PECAM-1 expression in pancreatic microcirculation was down-regulated. PECAM-1 expression had a significant difference between pancreatic microcirculation and peripheral circulation at the AEP8h time point (P<0.05). CONCLUSION: PECAM-1 expression on PMNs is in a converse way between pancreatic microcirculation and peripheral circulation in AEP.

Acute Disease↗

PubMed2004

[Changes of regional hemodynamics and microcirculation in patients with obliterating atherosclerosis in stage of chronic critical ischemia of the lower extremities before and after of restorational operation performance].

The state of regional hemodynamics and microcirculation in 47 patients with obliterating atherosclerosis of the lower extremities vessels in stage of chronic critical ischemia before and after performance of restorational operation was studied up. Ileo-femoral shunting using synthetic prosthesis was done in 9 patients and femoro-popliteal shunting--in 38. In 46 patients, in whom before the operation, basing on the Doppler flowmetry data, the preservation of the microcirculation bed functional reserves was noted, after the operation the increase of the regional blood flow and microcirculation indexes was observed beginning from the first up to the fifth day. In one patient the insufficient functional reserve of the microcirculation bed was revealed, the realization of restorational operation turned out to be ineffective, the lower extremity amputation was performed. The dynamics of the microcirculation changes on the first, third, fifth and seventh postoperative days was shown.

Adult↗

PubMed2004

The impact of topical antiseptics on skin microcirculation.

AIM: Antiseptics are commonly used in clinical practice to disinfect tissue and to avoid infections. However, topical antiseptics are assumed to have an influence on skin microcirculation, per se. Thus, the aim of the study was to analyse the influence of topically applied antiseptics on the microcirculation of intact skin in vivo. MATERIALS AND METHODS: The investigation was carried out on ears of male hairless mice (SKH-1hr, n = 25). The influence of four antiseptics was examined. Sodium chloride 0.9% served as control. An alcohol-based solution with a mixture of ethanol, 2-propanol and purified water (Softasept), an antiseptic with octenidine dihydrochloride and phenoxyethanol as the main active agents (Octenisept), as well as hexamethylenbiguanide (Lavasept) and 70% ethanol were tested. Intravital fluorescence microscopy in combination with intravenous injection of the fluorescence dyes FITC-Dextran as plasma marker and Rhodamine 6G (leukocyte staining) allowed a quantitative analysis of standard microcirculatory parameters (vessel diameter, functional capillary density, red blood cell velocity, FITC-leakage and leukocyte endothelium interaction). Recordings of the microcirculation in several regions of interest (ROI) were made prior to application and after 10 min exposure time and 60 min after the baseline data. Data were evaluated off-line with aid of computer assisted analysis. RESULTS: The diameter of arterioles decreased after the treatment with the alcoholic solutions. The other two antiseptics (Octenisept and Lavasept) caused a significant increase. Functional capillary density (FCD) was significantly reduced after application of ethanol and Softasept. There was no reduction of FCD following application of Octenisept. After treatment with ethanol and Softasept there was a significant decrease in red blood cell velocity (RBCV). The use of Lavasept revealed a decrease of FCD and RBCV. In the Octenisept treated group RBCV shows a mild increase after 10 minutes. The application of ethanol, Softasept and Lavasept was characterized by a significant increase of leukocyte endothelium interaction (LEI). After treatment with saline and Octenisept LEI remained constant. All used antiseptics except of Octenisept caused a significant leakage of FITC-Dextran. CONCLUSION: The antiseptics used in this study all showed an influence on skin microcirculation. As expected, our findings show that the alcoholic solutions are most aggressive to skin microcirculation.

Administration, Topical↗

PubMed2005

[Microcirculation changes in the ventral prostates of rats after castration].

OBJECTIVE: To study the microcirculation changes in the ventral prostates of rats after castration and the role of microcirculation during the apoptosis of prostatic cells. METHODS: Thirty-six male adult rats were randomized to 6 groups: one was taken as the control, while the other 5 underwent measurement of the microcirculation in vivo by a D95 physiological signal acquisition system 12 h, 24 h, 72 h, 7 d and 14 d respectively after castration, and then were perfused with Chinese ink to trace the microvessels of the prostates. RESULTS: The microcirculation of the rats'prostates changed dramatically following castration. The diameter and density of the microvessels, especially in the distant and mediate ducts of the prostates, decreased dramatically, and so did the bloodflow velocity. CONCLUSION: The microcirculation plays a role during the process of apoptosis of prostatic cells, and might be the mechanism of " apoptosis shift".

Animals↗

PubMed2005

Morphologic changes in the microcirculation induced by chronic smoking habit: a videocapillaroscopic study on the human gingival mucosa.

PURPOSE: To analyze the gingival characteristics of microcirculation in vivo and to evaluate the effects of smoking by means of computerised videocapillaroscopic techniques. METHODS: 35 healthy non-smokers and 35 healthy smokers were examined. The characteristics of gingival microcirculation were examined using computerized videomicroscopic techniques. For each subject, visibility, course, tortuosity and any images characteristic of capillary loops, besides the possible presence of microhemorrhages, the average caliber of the capillary loops and the number of capillary loops visible per square millimeter were evaluated. The investigation was non-invasive and repeatable for each subject. RESULTS: The investigation of gingival mucosa revealed capillary loops with a course both parallel and perpendicular to the surface: close to marginal gingiva, the tops of the capillary loops often appeared as evenly distributed dots or commas; close to the papilla, microcirculation more frequently ran parallel to the surface, and its characteristics were similar to nail microcirculation. In smokers, it was possible to underline capillaries of a smaller caliber (P< 0.001) and a higher number of detectable capillaries (P< 0.001). An important correlation between the capillary tortuosity, close to the papilla, and the smoking habit (P< 0.001) was observed. This study has shown that the smoking habit represents a real risk factor for periodontal disease, which greatly affects microcirculation.

Adult↗

PubMed1991

[The beneficial effect of qigong on the ventricular function and microcirculation in deficiency of heart-energy hypertensive patients].

Ultrasonic cardiogram was performed on 120 aged subjects. Experiment showed that the left ventricular function in the hypertensive aged group (n = 80) was lower than that in the aged group (n = 40), while the left ventricular function in the deficiency of heart-energy hypertensive patients (n = 46) was the lowest in the non-deficiency of heart-energy hypertensive patients (n = 34). After practising Qigong for 1 year, the cardiac output (CO) was increased, the total peripheral resistance (TPR) was decreased, ejection fraction (EF) mitral valve diastolic closing velocity and mean velocity of circumferential fiber shortening (mvcf) tended to be increased. The results indicated that Qigong had a regulatory effect on haemodynamic alteration as well as on improvement of left ventricular function. Nailfold microcirculation detection of 120 aged subjects was made. It found that hypertension had an accelerating effect on the disturbance of microcirculation. The incidence of disturbance of microcirculation was 73.91% in the deficiency of heart-energy hypertensive patients, after 1 year Qigong practice, the incidence of disturbance of microcirculation was 39.13% (P less than 0.01). The result suggested that Qigong had an effect to improve the disturbance of microcirculation. The above data indicate that Qigong can benefit heart-energy and regulate the blood channel.

Aged↗

PubMed1990

The role of the pericytes of the adventitial microcirculation in the arterial intimal thickening.

Segments of rat femoral arteries, with one collateral each, occluded between ligatures and dissected from surrounding tissue, developed intimal thickening, with or without ligation of their collaterals. Numerous newly-formed capillaries from the surrounding arterial microcirculation growing into the adventitia, tunica media and intimal thickening were demonstrated by means of serial longitudinal sections, predominantly in the ostium of the collateral. When the ligatures were applied without damaging the microcirculation surrounding the artery and the normal continuity of the adventitial vessels was unchanged, earlier presence of intimal thickening was observed. When the fibrous layers of the adventitia were removed at the moment of the arterial ligation, the continuity between newly-formed vessels of the neoadventitia and those growing into the media and neointima was much more evident. It was then noted that the pericytes constituted a major component of the intimal thickening. The introduction of contrast material in microcirculation confirmed the connections between newly-formed adventitial and intimal vessels. At the beginning of the experiment, autoradiographic studies showed an increased DNA synthesis in the cells of preformed postcapillary venules and capillaries of surrounding arterial microcirculation and later in those of the newly-formed vessels growing into the arterial wall. These results indicate that newly-formed capillaries derived from surrounding arterial microcirculation penetrate the wall of the occluded arterial segments and contribute to the intimal thickening formation. It is likely that the pericytes and endothelial cells (EC) of these ingrowing vessels are sources of myointimal cells at the intimal thickening and of endothelium at the luminal surface, respectively.

Animals↗

PubMed1990

Discrepancies between total and nutritional skin microcirculation in patients with peripheral arterial occlusive disease (PAOD).

Clinical observations indicate that a discrepancy may exist between the total and nutritional skin microcirculation in extremities of patients with peripheral arterial occlusive disease (PAOD), which suggests a local maldistribution of blood flow. The present study was performed to investigate how the skin blood flow is locally distributed in the toes of patients with PAOD. The total skin microcirculation was evaluated by laser Doppler fluxmetry (LDF), and the blood flow in the nutritional skin capillaries by dynamic capillaroscopy. This combination was simultaneously used to study the nailfold microcirculation in the big toe of 12 legs of 8 patients with various degrees of PAOD, using 10 legs of 8 healthy subjects as control. Capillary blood cell velocity (CBV) was evaluated by a new computerized videophotometric technique (CapiFlow). It was found that the nutritional blood flow, as evaluated by CBV, was similar in both groups (0.2 vs. 0.25 mm/s, NS), whereas the total blood flow, as evaluated by LDF, was significantly (p less than 0.05) increased in toes of patients with PAOD (11.7 AU) in comparison to normal subjects (2.0 AU). The postocclusive reactive hyperemia was impaired for both CBV (6% vs. 70%, p less than 0.05) and LDF (14% vs. 50%, p less than 0.01) in the PAOD group. The prevalence of flow motion (30% vs. 80%) was significantly (p less than 0.05) lower in patients as compared to controls. It is concluded that the resting blood flow in the skin microcirculation is increased but maldistributed in patients with PAOD. The reactivity of the microcirculation is also impaired in the affected region.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗