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Biomedical subjects

E Ernst

Publications and source records attributed to E Ernst.

At least 685 records · Page 38Linked to original sources
PubMed1988

Irradiated blood platelet concentrates stored for five days--evaluation by in vitro tests.

Platelet concentrates, irradiated with 15 Gy and stored for 5 days at room temperature under standardized conditions, were evaluated by in vitro tests and electron microscopy, in a paired study with nonirradiated platelets from the same concentrates, to investigate their usefulness for transfusion. The results showed no significant differences between the two groups in pH, pO2, pCO2, in vitro platelet aggregation, LDH, beta-thromboglobulin and thromboxane-B2. Examination by electron microscopy showed a higher degree of degranulation in the 5-day-old platelets but no certain difference between irradiated versus nonirradiated platelets. On the basis of satisfactory in vitro storage properties, platelet concentrates can be stored for 5 days in PL-1240 bags after irradiation. However, we recommend irradiation just before transfusion whenever possible.

Blood Platelets↗
PubMed1988

Blood rheology in patients with transient ischemic attacks.

A complete ischemic stroke is associated with a significant hemorheologic disturbance leading to a rise of the viscous component of the peripheral resistance. This abnormality represents a consequence of the acute event. Nonetheless, it could be causally related to ischemia. In an attempt to clarify this question, 26 patients suffering from transient ischemic attacks were compared with controls in terms of blood and plasma viscosity, hematocrit, blood cell filterability, and erythrocyte aggregation. In patients there was a significant impairment of blood fluidity comprising plasma viscosity, blood cell filterability, and erythrocyte aggregation, suggesting that the flow properties of blood are jeopardized even before an acute stroke. Most likely this is due to the underlying arteriosclerotic process. Our results open the way to speculating that hemorheologic mechanisms might predispose to the development of a stroke by decreasing cerebral blood flow. If this hypothesis were true, it would have important therapeutic implications.

Adult↗
PubMed1988

Blood rheology associated with cardiovascular risk factors and chronic cardiovascular diseases: results of an epidemiologic cross-sectional study.

As part of an epidemiologic cross-sectional study to determine cardiovascular (CV) risk factors in the population (total serum cholesterol, smoking, blood pressure, and body weight) hemoglobin (Hb) and plasma viscosity (PV) were measured. A two-stage cluster sample of 5,312 persons, aged twenty-five to sixty-four (available 5,069) was selected from a mixed urban-rural target population of 282,279 inhabitants, from which 4,022 (79.3%) participated in the study. Patients with chronic myocardial infarction (MI), cerebral infarction (CI), angina pectoris (AP), and peripheral arterial disease (PAD) were identified by questionnaire. The results show that there is no age or sex dependency of PV in healthy participants, while hemoglobin shows the well-known sex difference. In contrast, PV increases continuously with age in the total population. In men, increased PV is found in untreated hypertension, in hypercholesterolemia, and in smokers. In women, it is raised in hypercholesterolemia and in gross obesity. Male MI patients and patients of both sexes after CI in particular show statistically significantly elevated PV. Finally, in male patients with chronic AP or patients of both sexes with PAD, PV is elevated and a tendency to higher Hb values is seen. These results confirm smaller clinical trials suggesting that blood fluidity is pathologically altered in patients with CV risk factors or diseases. Since impaired blood fluidity may worsen the hemodynamic situation, in particular in patients with limited vasomotor reserve, hemorheologic parameters may be of prognostic relevance. Therapeutic implications of these findings should be considered.

Adult↗
PubMed1988

ELISA estimations of rheumatoid factor IgM, IgA, and IgG in sera from RA patients with high disease activity. DTT treatment studies.

Although Elisa assays detecting rheumatoid factor's (RF) show high sensitivity and specificity, difficulties with IgA- and especially IgG-RF testing in ELISA systems, due to interaction from 'contaminating' IgM-RF is still thought to be a problem. Sera from 15 Rheumatoid Arthritis patients with high disease activity and high IgM-RF values were Dithiothreitol (DTT) treated. IgM-RF values were reduced to approximately zero in all tested sera. IgA-RF activity declined as expected, but also showed a statistically significant correlation between % reduction after DTT treatment and the IgM-RF value from the same serum sample. IgG-RF also decreased after DTT treatment, most pronounced for high IgG-RF values. A correlation (not statistically significant) between the % reduction in IgG-RF after DTT treatment and the IgM-RF value from the same serum sample was observed. Pepsin and Diethylammonium ethyl (DEAE) reduced the IgG-RF activity even more than after DTT treatment of the sera. Fractionation by Gel filtration of 8 serum samples showed that all the RF activity were found according to the 'first top' of the gel filtration curve.

Arthritis, Rheumatoid↗
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

Influence of regular physical activity on blood rheology.

Blood rheology is one of the determinants of blood flow which becomes important when vasomotor reserve is limited or exhausted. It can be quantified ex vivo by measuring blood and plasma viscosity, haematocrit, red cell deformability and aggregation. To investigate the effects of regular exercise, a number of different experimental approaches were undertaken. A cross-sectional comparison of male athletes with sedentary matched controls showed that blood and plasma viscosity were lower and red cell deformability better in sportsmen. A 3-month longitudinal study of initially untrained healthy volunteers performing regular training revealed a fall of blood viscosity and an amelioration of red cell deformability. Finally a 2-month trial submitting claudicants to regular treadmill exercise showed a progressive fall in blood and plasma viscosity and a rise in red cell deformability. This suggests that an improvement in blood fluidity can be induced by regular physical exercise regardless of whether the blood rheology was normal or abnormal at baseline. The relevance of these findings could be three-fold. Firstly the "better than normal" blood rheology in athletes may contribute to enhanced blood flow in the working musculature and thus increase work output. Secondly the data supports the thesis of a link between blood rheology and atherogenesis. Thirdly regular exercise might be a way of therapeutically increasing blood flow in ischaemic vascular diseases.

Blood↗