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Results for “Microcirculation”

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At least 901 records · Page 50Linked to original sources

PubMed2001

[Effect of caffeine on microcirculation of human ocular fundus].

PURPOSE: To determine the effect of caffeine on the microcirculation in the human ocular fundus. SUBJECTS AND METHODS: The microcirculation of the ocular fundus in 10 eyes of 10 healthy volunteers was studied using a laser speckle tissue circulation analyser. 100 mg of caffeine or placebo was given orally in a double-blind test. Square blur rate(SBR), a quantitative index of blood flow velocity, was measured in the temporal site of the optic nerve head(ONH) free of surface vessels and in the middle site of the choroid-retina between the ONH and the macula. Intraocular pressure(IOP), blood pressure(BP), pulse rate(PR), and central critical fusion frequency(CFF) were also measured. These parameters were measured before and for 2 hours after administration. The area under curve(AUC), of the SBR was calculated for each area. Ocular perfusion pressure(OPP) was also obtained from blood pressure and intraocular pressure. RESULTS: The time-course change of SBR value showed much individual difference. Caffeine decreased the AUC of the SBR in the ONH as well as in the choroid-retina significantly. IOP, mean BP, PR, OPP and central CFF did not change significantly. CONCLUSIONS: These results suggest that caffeine may increase blood vessel resistance and decrease blood flow in the ONH and choroid-retina in humans.

Adult↗

PubMed2000

[Changes in microcirculation and their correction in patients with varicose veins and post-thrombotic syndrome].

Variety of disturbances of microcirculation can be stipulated by vasomotorial disfunction's of blood circulation in terminal vascular bed, changes of rheologic and coagulative characteristics of blood as well as morphological changes of structure of tissue and vessels of microcirculatory bed of destructed lower limb. In case of a varicose disease without complications changes of microvessels are considered to be compensatory adaptation. Patients suffering from a complicated type of varicose disease and post-thrombotic syndrome have "failure" of compensatory adaptation reaction. It results from significant functional disturbances of microcirculation and sudden morphological changes of structure of blood and lymphatic capillaries and tissue of a destructed lower limb. Correlative dependence can be found between degree of clinical evidences and a level of structural changes of microcirculatory bed. They are mostly significant in groups of patients having complicated varicose disease and post-thrombotic syndrome. It was shown that functional and morphological states of microcirculatory bed are of prognostic importance for estimation of effectiveness of operative interferences during diseases being analysed.

Adolescent↗

PubMed2001

Peripheral microcirculation during pregnancy and in women with pregnancy induced hypertension.

During pregnancy the cardiovascular system undergoes several changes so as to adapt the maternal organism to the strains of pregnancy. These adaptations can assume a pathological development in persons with a previous history of cardiovascular problems. On the other hand the absence of these adaptations may lead to a pathological course of pregnancy. Pregnancy induced hypertension (PIH) may be such a pathological development due to maladaptation. The causes are for the most part unknown. For some time it has been assumed that it is due to microcirculatory disorders. Using periungual capillary microscopy the present study prospectively investigated the changes in peripheral microcirculation during pregnancy focussing on pregnancy induced hypertension. Sixty-seven women with a normal course of pregnancy and 28 women with pregnancy induced hypertension were evaluated. Throughout the prospective study 3 examinations were performed during pregnancy and one during childbed. The women who developed a PIH were registered during the third trimester. Erythrocyte velocity at rest and vascular reagibility of capillaries following a 3 minute ischaemia were evaluated. In the course of pregnancy a significant increase of approximately 30% in erythrocyte velocity could be observed. Interpolation to obtain the best strait line result demonstrates that it is a continuous increase. Erythrocyte velocity returns to normal in the course of 14 weeks post partum. Due to a physiological vasodilatation during pregnancy, vascular reaction to ischaemic stress significantly decreases. During childbed these changes return to normal. Examinations on women with pregnancy induced hypertension not only showed a significant reduction of microcirculation under resting conditions but also a different pattern of reaction to ischaemic stress. Erythrocyte velocity under resting conditions lies 36% below normal values. Furthermore the distinctly shortened hyperaemic period indicates a hightened sensitivity to vasoconstrictive substances in women with PIH. While taking into account the clinical data a positive correlation with the severity of the illness was able to be established.

Adult↗

PubMed2001

[Myocardial microcirculation in patients with systemic lupus erythematosus].

AIM: To examine myocardial microcirculation in patients with SLE. MATERIAL AND METHODS: Examination of 21 SLE patients consisted of perfusion tomoscintigraphy of the myocardium with Tl-201 at rest and in combination with bicycle exercise. Various protocols were used. RESULTS: The majority of SLE patients had resting disorders of myocardial perfusion: 5 had macrofocal scar lesion of the myocardium, 12 had disorders typical for small-focal myocardial fibrosis. Normal distribution of the perfusion occurred in 4 cases. Tomoscintigraphy performed in combination with exercise test revealed in 11 of 15 patients transient perfusion disturbances reflecting transient myocardial ischemia. One third of the patients had changes characteristic of myocardial ischemia due to coronary atherosclerosis. CONCLUSION: SLE patients have disorders of myocardial perfusion including those characteristic of scar lesion, small-focal cardiofibrosis and transient myocardial ischemia of different genesis: due to disorders in microcirculation and atherosclerotic lesion of major coronary arteries.

Adult↗

PubMed1998

[Effect of hyperbaric oxygen on cerebral microcirculation and tissue cells in animals with cerebral ischemic injury].

Changes of cerebral microcirculation and tissue cells after Hyperbaric Oxygen (HBO) exposure were observed in 136 gerbils with cerebral ischemia by observation of meningeal microcirculation pathological study in cerebral tissues and determination of Na, K-ATPase. It is indicated that HBO may be helpful in improving microcirculatory dynamics and other microcirculatory functions, and enhancing cerebral tissue cell activity and cell function, as well as increasing oxygen content. It is suggested that HBO (250 approximately 300kPa) may play a role in protecting vessel endothelial cells and nerve cells.

Adenosine Triphosphatases↗

PubMed2000

[Correlation between endothelin, nitric oxide and microcirculation in super-thinned skin flap in pig].

OBJECTIVE: To investigate the influence of the endothelin (ET) and the nitric oxide (NO) on the microcirculation of a super-thinned skin flap. METHODS: With pig, a super-thinned skin flap, only including subdermal vascular networks, was raised and sutured back on its bed on one flank of each pig, and on the other flank a traditional skin flap was also formed for the controlled group. A laser Doppler Flowmeter was used for evaluation of the blood circulation before and after the operation. The endothelin and the nitric oxide of the flap were examined after certain times of the operation. Furthermore, the necrosis of each flap was decided 7 days after the operation. RESULTS: The ET and NO were significantly increasing after 1 hour of the operation in both of the groups (the peak value of ET at 6 hours and NO at 3 hours after the operation). However, the ET in the super-thinned flap group was significantly lower at 1, 3, 6 hours after the operation, compared with the centrolled group (P < 0.05), but the NO measured meantime was significantly higher than the control (P < 0.05). The blood flow of the super-thinned flap was significantly higher than the control flap separately at 1, 3, 6 hours after the operation (P < 0.01). The survival of the super-thinned flap increased about 35% more than the control. There was a negative correlation existed between the ET and the blood flow, as well as a positive correlation between the NO and the blood flow. CONCLUSION: This study has indicated that the changes of the ET and NO in the flaps, especially in the super-thinned flap, have strongly correlated with their microcirculation. The highter survival rate of the super-thinned flap might owes to the mechanism which the ET in the flap produces less while the NO more, Compared with the traditional skin flap.

Animals↗

PubMed2001

Flight microangiopathy in medium- to long-distance flights: prevention of edema and microcirculation alterations with total triterpenic fraction of Centella asiatica.

The aim of this study was the evaluation of microcirculatory alterations associated with edema in passengers travelling for more than 3 hours and the study of the effects of TTFCA (total triterpenic fraction of Centella asiatica) on the development of microcirculation alterations and edema, in a prospective, randomized study. Laser Doppler flowmetry (LDF), transcutaneous PO2 and PCO2, rate of ankle swelling (RAS) were used. Subjects were randomized after informed consent into two groups: one control group (no drug or other treatment), and a treatment group (TTFCA 60 mg thrice daily for 2 days before the flight, the day of the flight, and for another day after the flight). Inclusion criteria were age range between 30 and 50, mild-moderate superficial venous disease with varicose veins. Subjects traveled in economy class. In controls there was a progressive increase in CO2, RAS, and edema score and a progressive decrease in flux (RF) and venoarteriolar response with flying time. The variations in all parameters were milder (p>0.05) in the TTFCA group. RAS and edema were significantly lower in the TTFCA-treated group (p<0.025). The progressive increase in RAS, PCO2, and the decrease in VAR and O2 were linearly associated with flight time (up to 10 hours). These results are very interesting and indicate an option for patients prone to edema and microcirculation disturbances during long flights.

Adult↗

PubMedDate not supplied

Effects of inspired oxygen concentration on peripheral microcirculation studied by the rabbit ear chamber method.

The effects of oxygen inhalation on peripheral hemodynamics were studied in vivo. We observed changes in the cutaneous microcirculation in the rabbit under various inspiratory oxygen concentrations. Blood vessel diameter, blood-flow velocity and blood-flow rate were gradually reduced as oxygen concentrations were increased from 30%. These results indicate that inspiration of more than 30% oxygen causes deterioration of the microcirculation.

Administration, Inhalation↗

PubMed2001

[The effects of free radical oxidation on skin surfaces with disturbed microcirculation].

Quantity of primary and secondary products of peroxide oxidation of lipides in the case of broken microcirculation was investigated in biophates of skin. It was found that broken microcirculation led to the surplus accumulation of products of lipide peroxide oxidation. Prooxydanto-oxydantic homeostasis disturbance has very strong influence on premature skin atrophy.

Adult↗

PubMed2000

[Protective effect of Ginaton on rat liver microcirculation disturbance following liver xenotransplantation].

OBJECTIVE: To study the effect of Ginaton on liver microcirculation disturbance following liver xenotransplantation in rats. METHODS: Ginaton was injected intravenously to recipients at a dosage of 14 mg/kg before graftng liver of guinea pigs. The portal blood flow (PBF) was measured by Doppler ultrasound at 0, 30 and 60 minutes after transplantation, and the pathologic changes of liver and heart were observed. RESULTS: The reperfusion status of control group was poor and leukocyte infiltration appeared in the center of lobute following transplantation and myocardial cells were impaired. Significant reduction in PBF was found in rats following transplantation. Ginaton pretreatment distinctly ameliorated PBF. The speed of PBF was closely correlated with the pathologic changes following transplantation. CONCLUSION: In the process of liver transplantation, ischemia reperfusion damage may lead to xenoheptic microcirculaton disturbance. Ginaton could improve the xenoheptic microcirculation and reduce ischemic reperfusion damage.

Animals↗

PubMed2000

[Microcirculation of thoraco-acromial flaps: monitoring and clinical application].

OBJECTIVE: To monitor the microcirculation of thoraco-acromial flaps. METHODS: The microcirculation in 12 thoraco-acromial flaps was monitored continuously by laser Doppler flowmetry (LDF). RESULTS: The microcirculatory changes in thoraco-acromial flaps were divided into two phases: rapid rising (2 - 4 days after operation) and plateaurising (4 - 7 days after operation). PU values were 7.4 +/- 2.0, 7.6 +/- 2.3 and 7.3 +/- 1.6. CONCLUSIONS: In division of the thoraco-acromial flaps within the plateau, the value (PU) returned to or exceeded 50% of that before application of the tourniquet. All flaps survived. The time of division was decreased to 6 - 8 after operation days.

Adolescent↗

PubMedDate not supplied

Treatment of venous ulcers with pentoxifylline: a 12-month, double-blind, placebo controlled trial. Microcirculation and healing.

The aim of this study was the evaluation of the treatment of venous ulcers with pentoxifylline (PXF) in 12 months. This double-blind, placebo-controlled trial was conducted in GCP. Patients were included after consent and randomized for PXF (400 mg three times daily) or placebo. The number of healed ulcers, the variation in the area of ulceration, and the variation in microcirculatory parameters (laser-Doppler flux and skin PO2) were considered as endpoints. Of the 85 patients included, 80 completed the study (41 in the PXF and 39 in the placebo group). The groups were comparable. Healing occurred in 88% of limbs in the PXF and in 44% in the placebo group (44% difference; p<0.02). The average area reduction was 93% in the PXF and 56% in the placebo group. Microcirculation was significantly improved in both groups at 12 months. The decrease in flux and the increase in PO2 were greater in the PXF group (p<0.05). Considering the proportion of healed ulcers a better outcome was observed with PXF (p<0.02; 12% of nonhealed ulcers in the PXF vs 56% in the placebo group). The ulcerated area decreased 93% in the PXF vs 56% in the placebo group (40% difference; p<0.02). Tolerability was comparable (6% in the PXF group and 5% in the placebo group complained for treatment). No important side effects were observed. In conclusion, treatment with PXF in venous ulcers improves healing and microcirculation and should be considered in slow-healing venous ulcers.

Aged↗

PubMed2002

[Parameters of membrane permeability, microcirculation, external respiration, and trace element levels in the drug-laser treatment of pneumonia].

AIM: To study effects of laser therapy in combined treatment of pneumonia on external respiration function, membrane permeability, microcirculation and serum trace elements. MATERIAL AND METHODS: 142 pneumonia patients were randomly divided into two groups: 96 patients treated with drugs and laser radiation (the study group) and 46 patients treated with drugs only (control group). RESULTS: In the study group there was more pronounced reduction in cell membrane permeability, a rise in concentrations of iron and chromium in the blood serum, improvement of microcirculation. These changes closely correlated with those in immunity, external respiration function. CONCLUSION: Laser therapy is an effective method of pneumonia treatment and can be included in relevant combined schemes.

Adolescent↗

PubMed2002

Beneficial role of melatonin on microcirculation in endotoxin-induced gastropathy in rats: possible implication in nitrogen oxide reduction.

BACKGROUND AND PURPOSE: Lipopolysaccharide (LPS) induces hemodynamic changes and microcirculatory derangement in various organs. Melatonin may exert a beneficial effect on gastric tissue in LPS-induced gastropathy. However, the role of nitric oxide (NO) has not been clarified. MATERIALS AND METHODS: Adult male Sprague-Dawley rats were divided into three groups: control, n = 9; LPS (intraperitoneal LPS, 50 mg/kg), n = 9; and LPS + M (LPS, 50 mg/kg; intragastric melatonin 20 mg/kg), n = 9. Mean arterial blood pressure (MAP) was monitored throughout the experiment (8 h). In vivo microscopy was used to investigate gastric microcirculation, including flow velocity and leukocyte adhesion. Tissue malondialdehyde (MDA) and gastric aspirate parameters (protein content, glucose content, volume) were determined as the gastric damage index at the end of the experiment. Microdialysis was used to measure the sum of nitrite and nitrate concentrations. RESULTS: Compared with LPS alone, LPS with melatonin significantly improved gastric microcirculation but not systemic hemodynamics. LPS-induced gastropathy was quantified according to the increased adherent leukocyte count, decreased flow velocity in postcapillary venules, and increased tissue MDA production. Luminal glucose and protein content, the gastric mucosa injury index, were significantly increased. Intragastric melatonin improved microcirculatory and mucosa injury parameters. These effects of melatonin are directly associated with the tissue levels of NO products, which are increased with LPS only and much decreased with LPS and melatonin. CONCLUSIONS: This study demonstrated that melatonin contributes to the protective effects in LPS-induced gastropathy through a mechanism associated with regional production of NO.

Animals↗

PubMed1975

[Certain clinico-morphological aspects of microcirculation in partients with chronic nonspecific pneumonia and chronic cor pulmonale].

Clinical and morphological studies conducted in chronic non-specific pneumonias and chronic cor pulmonale have demonstrated that these lesions are accompanied by important disorders in the system of microcirculation that manifest themselves in alterations in the rheologic properites of the blood, and in a generalized deterioration of the vascular terminals in the lungs and pleura that are due to the chronic inflammatory process, hypoxia, haemodynamic disorders, and that result in a diffuse intravascular thrombosis. The disturbances in free blood circulation in the microcirculatory system entail significant metabolic shifts that determine the severity of the disease, its progressive course, and lethal result. The increasing intravascular blood clotting in the postcapillary and venular portions of the microcirculatory system, along with a partial reduction of the capillary link, results in an exclusion of a certain portion of the peripheral vascular bed from the circulation process, thus favouring the progress of pulmonary hypertension. Distinct impairment of the coagulation properties of the blood in the microcirculation system in cases of chronic nonspecific pneumonias, stage II-III, and in chronic cor pulmonale require a timely correction thereof, and support the suggestion of the authors as to the inclusion of anticoagulants into the complex of the rapeutic measures for this category of patients.

Adult↗

PubMed2002

[Hypertension and microcirculation].

The importance of the microcirculation (comprising the smallest arteries, arterioles, capillaries and venules) in hypertension and other cardiovascular diseases is well known. The small resistance arteries develop structural changes such as an increase in the wall/lumen ratio and the capillary networks of different vascular beds become rarefied in response to increased blood pressure. These changes not only contribute to hypertensive lesions of target organs but also maintain or amplify the increased blood pressure by increasing peripheral resistances, so creating a vicious circle. Microvascular changes in hypertension may also lead to an increased reflection of the pressure wave towards the heart from the peripheral reflecting sites. This reflected wave also increases systolic blood pressure without increasing the diastolic pressure, thereby increasing the pulse pressure. A high pulse pressure may induce lesions of the vessel walls and of the endothelium of the large arteries, and this is known to be a significant independent risk factor for cardiovascular mortality, especially in the elderly. Microvascular rarefaction could possibly be reversed by therapeutic angiogenesis with cytokines but this treatment is difficult to deliver to the myocardium and is not yet available in clinical practice. Some conventional antihypertensive therapies, including the association of a low dose angiotensin converting enzyme inhibitor, perindopril, and a diuretic, indapamide, may have a beneficial effect on the microcirculation. It has been demonstrated clinically that these drugs specifically reduce the pulse pressure, probably by decreasing the reflected pressure wave, and, therefore, additional benefits in terms of a reduction of cardiovascular risk can be expected.

Arterioles↗

PubMed2002

[Influence of spray application of La Léchère mineral water on the cutaneous microcirculation in the lower limbs in healthy subjects].

Spa treatment is commonly used in chronic venous diseases, to the satisfaction of many patients, but no scientific validation work has been performed up to now. This pharmaco-clinical study was designed to evaluate the specific influence of topical application of the mineral water of La Léchère on the cutaneous microcirculation. It was a controlled, randomized, double-blind study comparing the effects of the water of La Léchère to distilled water applied as a spray to the ankle in ten healthy subjects. Skin temperature and laser-Doppler perfusion index (mean and temporal variability) were the evaluated parameters. Under these conditions, the results show a cutaneous cooling with a mean value of 0.3 to 0.5 degrees C, whose duration is significantly longer with the thermal water (p<0.05). During this cooling, the laser-Doppler perfusion index remained stable when distilled water was applied, whereas an increase was observed when the thermal water was employed (p=0.005). No significant changes in vasomotion were observed with either treatment (p=ns). This study demonstrates the presence of a specific effect of topical application of the La Léchère mineral water on the cutaneous microcirculation. The explanation and the potential therapeutic interest of this effect were beyond the scope of this study and remain to be investigated.

Administration, Cutaneous↗

PubMed2002

[Microcirculation of lateral groin skin flaps: monitoring and clinical application].

OBJECTIVE: To monitor the microcirculation of lateral groin skin flaps. METHODS: The microcirculation in 12 lateral groin skin flaps was monitored continuously by laser doppler flowmetry (LDF). RESULTS: The microcirculatory changes in lateral groin skin flaps were divided into two phases: rapid rising (2-6 days after operation) and plateau (6-11 days after operation). PU values were 2.83 +/- 0.46, 3.21 +/- 0.41, 3.66 +/- 0.43, 4.77 +/- 0.71, 7.08 +/- 0.37; 7.53 +/- 0.41, 7.57 +/- 0.62, 7.70 +/- 0.44, 7.60 +/- 0.26, 7.58 +/- 0.17. CONCLUSION: In clinical application, division of the lateral groin skin flaps within the plateau, and the values (PU) returned to or exceeded 50% of that values (PU) determined before application of the tourniquet, causes flaps survival (100%). The time of division was decreased to 8-11 postoperative days in our clinical application.

Adolescent↗