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Biomedical subjects

A Matrai

Publications and source records attributed to A Matrai.

At least 37 records · Page 2Linked to original sources
PubMed1988

Diltiazem alters blood rheology.

A study was carried out to investigate whether diltiazem influence blood rheology, as has been reported for some other calcium channel blockers. Twenty patients with clinical, stable angina pectoris were treated with 2 x 90 mg diltiazem per day for 2 weeks. Blood viscosity, plasma viscosity, haematocrit, blood cell filterability and red cell aggregation were taken as in vitro measures quantifying the flow properties of blood. After 1-week's treatment, low and middle shear blood viscosity had declined significantly. This change was more pronounced after 2-weeks' medication. At this point, there was also an increase in blood cell filterability. All other variables did not show significant alterations. The results suggest a significant fluidification of blood during diltiazem treatment. This effect may reduce the viscous component of the total peripheral resistance, and therefore, it may contribute to an increase in perfusion and to the anti-anginal properties of the drug.

Adult↗
PubMed1987

Placebo-controlled, double-blind study of haemodilution in peripheral arterial disease.

Twenty-four men who had stable claudication with long, collateralized femoropopliteal obstructions were treated by isovolaemic haemodilution and sham dilutions in a double-blind, placebo-controlled, crossover study. 3 weeks of haemodilution lowered haematocrit and blood viscosity and increased resting blood flow and pain-free walking distance. Sham treatment produced no such favourable changes. It is concluded that haemodilution therapy can be clinically effective in patients with arterial obstructions in the legs. It seems particularly promising when the vascular obstructions are such that low average shear stresses act on the blood in multiple, long collaterals.

Blood Circulation↗
PubMed1987

Leukocytes and the risk of ischemic diseases.

Predictive indexes for atherosclerotic risk are imperfect, suggesting that there are predictive factors not commonly considered. Such a factor may be the white blood cell (WBC) count. Epidemiologic studies have shown correlations between the WBC count and the risk of myocardial infarction and stroke. The risk of acute myocardial infarction is approximately four times as great in persons with WBC counts high in the normal range (greater than 9000/microL [9 X 10(9)/L]) as in persons with WBC counts low in the normal range (less than 6000/microL [6 X 10(9)/L]); only 50% to 65% of the excess risk of the high-count individuals is explainable by tobacco smoking (which covaries with WBC count). A high WBC count also predicts greater risk of reinfarction and of in-hospital death. Less rigorously studied, the constitutional neutropenia of Yemenite Jews appears to afford protection against atherosclerotic disease. Among WBC types, the strongest epidemiologic association has been with the neutrophil count. Such a predictive value of WBC count is plausible and satisfying, because WBCs make a major contribution to the rheologic properties of blood; alter adhesive properties under stress--including the stress of ischemia, enhancing their rheologic importance; and participate in endothelial injury, both acutely and chronically, by adhering to endothelium and damaging it with toxic oxygen compounds and proteolytic enzymes. Techniques newly developed or under development may allow us to refine the predictive value of the WBC count by combining it with measures of cell activation and/or activatability.

Blood Vessels↗
PubMed1987

Blood viscosity in patients with bone fractures and long term bedrest.

Eighteen patients with bone fractures and without systemic disease were studied for blood rheology. Blood and plasma viscosities, haematocrit, red cell aggregation and filterability as well as plasma colloid oncotic pressure were measured. Results show that patients exhibit a substantial haemorheological deficit on admission. During bedrest this returns to normal, owing to marked 'autohaemodilution'. It is concluded that trauma causes increased viscosity of blood in these patients. This change could predispose to deep vein thrombosis. However, such a risk is reduced by 'autohaemodilution' which is most probably an effect of immobilization.

Bed Rest↗
PubMed1987

Abstention from chronic cigarette smoking normalizes blood rheology.

Smokers differ in terms of blood rheology from non-smokers. Ex-smokers differ from smokers but not from non-smokers. When investigated while abstaining from nicotine for 8 weeks, chronic cigarette smokers show a gradual normalization of blood and plasma viscosities, haematocrit, blood cell filterability, plasma fibrinogen levels as well as total white cell count. Those smokers who did not manage to abstain, reveal no such changes. The findings suggest that haemorheological alterations caused by smoking are reversible. This might play a role in the reduction of cardiovascular risk and in the elevation of tissue perfusion.

Adult↗
PubMed1987

Dose-effect relationship between smoking and blood rheology.

Five groups of male blood donors were investigated. The first group had never smoked, the second were ex-smokers, the third smoked between 10 and 20 cigarettes per day, the fourth between 21 and 40, and the fifth more than that. Haematocrit, white cell count, plasma and native blood viscosity, blood cell filterability and aggregation, plasma colloid oncotic pressure as well as fibrinogen were measured. Results show that smoking is associated with a progressive significant deterioration of the above haemorheologic variables. These changes are interpreted as an absolute and a relative polycythaemia possibly in conjunction with a chronic inflammatory process. It is concluded that smoking induces a dose-related increase in viscosity of blood among young men which is reversible by abstention.

Adult↗
PubMed1987

Importance of the preoperative haemoglobin concentration in arterial surgery.

A study of reconstructive operations for ischaemia of the legs showed a correlation between a high preoperative haemoglobin level and early postoperative reocclusion. The mean preoperative haemoglobin level of patients with early reocclusion (165 +/- 3 g/l, SEM) was significantly higher (p less than 0.001) than that of patients who did not reocclude (153 +/- 3 g/l). There was no significant difference in the total serum protein concentrations, suggesting that dehydration was not the cause of the difference observed in haemoglobin concentration. The mechanism may be the lower flow rate associated with the higher haemoglobin content and increased blood viscosity.

Arteries↗
PubMed1987

Intermittent claudication, exercise, and blood rheology.

Forty-two stable patients with claudication were assigned to two groups. Group I (n = 22) was submitted to regular, standardized treadmill exercise for 2 months. During this time the maximal and pain-free walking distances increased significantly (more than 100%). Group II (n = 20) patients did not exercise over the same period of time, and their walking distances remained essentially unchanged. No drugs or other forms of treatment were given in either group. The rheology of blood, as quantified by blood and plasma viscosity, hematocrit, blood filterability, and red cell aggregation, was initially abnormal in patients as compared with matched controls. Blood and plasma viscosity, blood cell filterability, and red cell aggregation normalized significantly in group I, but remained pathologic in group II. The hemorrheologic values of patients after 2 months of exercise did no longer differ significantly from those of healthy controls. The "fluidification" of blood induced by regular exercise was qualitatively and quantitatively similar to that obtainable by hemorrheologically active medications. The results confirm that physical training is clinically effective in patients suffering from claudication. They furthermore suggest that training may be looked on as a form of "hemorrheologic therapy" suitable for increasing the fluidity of blood in patients with ischemic diseases. Part of the benefits of regular exercise in stage II occlusive peripheral arterial disease may result from changes in hemorrheology; further studies are needed to define the mechanism.

Aged↗
PubMed1986

Cardiovascular risk factors and hemorheology. Physical fitness, stress and obesity.

To date there is little information about hemorheological data in the presence of secondary risk factors. Inter- and intraindividual comparisons of hemorheological parameters show that fitness has a significant influence on blood fluidity as quantified by ex vivo measurements of blood and plasma viscosity, red cell filterability and red cell aggregation. In fitter individuals blood is more fluid. Similar observations can be made with stress. Prolonged psychoemotional stress leads to a loss in blood fluidity and red cell filterability. Finally a comparison between excessively obese patients and healthy controls reveals a deterioration in hemorheological parameters in the obese group. These results, together with reports from the literature suggest that all accepted cardiovascular risk factors are associated with abnormalities in the flow properties of blood. It is proposed that partly the same phenomena are involved in the genesis of atherosclerotic lesions and influence rheological properties of blood.

Adolescent↗
PubMed1986

Blood rheology in vegetarians.

1. Blood rheology has been quantified by measuring blood and plasma viscosity, packed cell volume (PCV), erythrocyte filterability and erythrocyte aggregation in forty-eight voluntary vegetarians and compared with matched controls. 2. Results show that in vegetarians, values for PCV were lower than those in controls, leading to reduced native blood viscosity. In addition PCV-standardized blood viscosity was also decreased. This was brought about mostly by lower plasma viscosity. Erythrocyte rheology seemed to be unaltered. Stricter avoidance of animal products was associated with even lower values for these indices. 3. These observations are in agreement with the fact that other low-cardiovascular-risk groups show better than average blood fluidity. They are consistent with the hypothesis that in vitro measurements of blood rheology may provide signs of early atherosclerotic changes in vivo.

Adolescent↗
PubMed1986

Altered red and white blood cell rheology in type II diabetes.

Twenty-three patients suffering from type II, non-insulin-dependent diabetes were compared with matched controls. Suspensions with standardized white and red cell counts were filtered in a novel device capable of discriminating filter occlusion and cell transit time. Results confirm previous studies indicating that red cell deformability is impaired in diabetes. According to our findings, this may be caused by a slight overall loss of red cell fluidity together with the existence of a subpopulation of more markedly rigid erythrocytes. Furthermore, we demonstrate that white cell filterability is reduced in type II diabetes. This could be due to decreased white cell deformability, increased white cell adhesion, or both. Analysis of diabetic subgroups indicates that the white cell rheology is impaired to a greater extent in patients taking oral antidiabetic drugs than in patients controlled by diet alone. Altered white cell rheology could help to explain the pathological blood cell filterability frequently reported in diabetes. More important, impaired white cell rheology might significantly contribute to microcirculatory flow abnormalities jeopardizing O2 exchange in the terminal vascular bed.

Adult↗