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Biomedical subjects

K Gjesdal

Publications and source records attributed to K Gjesdal.

At least 91 records · Page 5Linked to original sources
PubMed1985

Increased arterial adrenaline is highly correlated to blood pressure and in vivo platelet function in pre-eclampsia.

Compared with normotensive pregnant women (n = 13), patients with severe pre-eclampsia (n = 13) had increased arterial plasma adrenaline (P < 0.001), peripheral venous adrenaline (P < 0.01), arterio-venous differences of adrenaline (P < 0.001) and venous concentration of the platelet release product beta-thromboglobulin (P < 0.001). In the pre-eclamptic group, arterial adrenaline correlated with mean blood pressure (r = 0.90, P < 0.001), heart rate (r = 0.78, P < 0.01) and beta-thromboglobulin (r = 0.82, P < 0.001), while in the normotensives adrenaline correlated only with beta-thromboglobulin (r = 0.76, P < 0.01). According to these results, sympathetic adrenal tone is increased in pre-eclampsia and may play a role in the pathogenesis of high blood pressure and platelet activation in this disease.

Adult↗
PubMed1983

Increased beta-thromboglobulin in essential hypertension: interactions between arterial plasma adrenaline, platelet function and blood lipids.

Twenty-three 50-year-old men with untreated, essential hypertension had elevated plasma concentrations of the platelet release product beta-thromboglobulin (BTG) compared to 14 age-matched control men (p less than 0.01). BTG correlated with arterial plasma adrenaline concentrations in the hypertensive (r = 0.44, p less than 0.05), normotensive (r = 0.73, p less than 0.01) and combined group (r = 0.51, p less than 0.01). Significant correlations (p less than 0.05) between BTG and cholesterol (LDL + VLDL fraction) were observed both in the hypertensive and the normotensive group. In the hypertensive group arterial adrenaline correlated with cholesterol (LDL + VLDL) (p less than 0.05). These findings are consistent with increased platelet activity in middle-aged men with essential hypertension, and may indicate that plasma adrenaline influence platelet function. The risk factors for coronary artery disease (blood pressure, lipid status, stress as evidenced by catecholamine release and platelet function) were positively related. Measurement of arterial instead of venous adrenaline is essential for the demonstration of the associations presented.

Beta-Globulins↗
PubMed1977

Half-life of platelet factor 4 (PF-4) in plasma and platelets from macaca mulatta.

Human platelet factor 4 (PF-4) showed a reaction of complete identity with PF-4 from Macaca mulatta when tested against rabbit anti-human-PF-4. Such immunoglobulin was used for quantitative precipitation of in vivo labelled PF-4 in monkey serum. The results suggest that the active protein had an intra-platelet half-life of about 21 hours. In vitro 125I-labelled human PF-4 was injected intravenously into two monkeys and isolated by immuno-precipitation from platelet-poor plasma and from platelets disrupted after gel-filtration. Plasma PF-4 was found to have a half-life of 7 to 11 hours. Some of the labelled PF-4 was associated with platelets and this fraction had a rapid initial disappearance rate and a subsequent half-life close to that of plasma PF-4. The results are compatible with the hypothesis that granular PF-4 belongs to a separate compartment, whereas membrane-bound PF-4 and plasma PF-4 may interchange.

Animals↗
PubMed1977

Platelet function during reconstructive peripheral arterial surgery.

During reconstructive arterial surgery on nine patients suffering from obliterating femoral arteriosclerosis, the number of platelets, the percentage of reversible platelet aggregates, and the plasma concentration of a platelet release marker (platelet factor 4, PF-4) were determined. Blood samples were collected simultaneously from the popliteal vein of the leg operated upon, and from the superior caval vein and radial artery at various stages of the operative procedure. Only slight changes in platelet number were observed. Platelet aggregates increased in blood from all sampling sites during ischaemia, but corresponding values were in general lower in arterial than in venous blood. The percentage of reversible platelet aggregates in the popliteal vein rose considerably during ischaemia, and the rise correlated well with the arterial occlusion time (Rs = 0.96). PF-4 concentration rose throughout the procedure. Although the clinical implications of these findings are not clear, they seem to underline the importance of a swift but careful surgical technique and a short period of main vessel occlusion.

Aged↗
PubMed1976

Effects of fasting on plasma and platelet-free fatty acids and platelet function in healthy males.

10 healthy male volunteers fasted for 72 hours. Their plasma concentration of free fatty acid increased more than two-fold, to 1.8 mmol/l. The number of reversible venous "in vivo" platelet aggregates increased significantly (p less than 0.01); this figure correlated with the concentration of long-chain saturated free fatty acid in plasma (p less than 0.02). The correlation with the amount of long-chain saturated free fatty acid plus oleic acid (18:1) was even better (p less than 0.01). Plasma PF-4 concentration increased, suggesting increased platelet release reaction. In spite of the plasma increase, total platelet FFA concentration was reduced and there was a change in the distribution of platelet free fatty acid which correlated with the degree of aggregation.

Adult↗
PubMed1976

Lung responses and platelet release reaction following induced intravascular platelet aggregation in the cat.

Pulmonary microembolism secondary to intravascular platelet aggregation causes a rise in pulmonary vascular resistance and a decrease in dynamic lung compliance. The relationship between these lung responses and the platelet release reaction was investigated in the cat. Repeated episodes of platelet aggregation were induced by intravenous infusions of either ADP or collagen. Platelet release was evaluated by serial determinations of the plasma concentration of platelet factor 4 (PF-4). An increased plasma concentration of PF-4 was found after the initial episode of such induced intravascular platelet aggregation. Consecutive infusions of an aggregating agent still elicited vigorous lung responses, but no further increase in the plasma concentration of PF-4 was observed. There are different possible explanations for this lack of correlation between the lung responses and the PF-4 release. It may well be that the pattern of release for PF-4 does not reflect those release events which result in pulmonary smooth muscle contraction. Alternatively, but less likely, pulmonary smooth muscle constriction and platelet release could be fully independent phenomena.

Adenosine Diphosphate↗
PubMed1976

Platelet function and plasma free fatty acids during acute myocardial infarction and severe angina pectoris.

The relationship between platelet function and plasma free fatty acid concentration has been studied serially during the initial 24 h in 11 patients suffering from acute myocardial infarction and in 5 patients with severe angina pectoris, Similar results were obtained in the 2 groups. Plasma free fatty acid concentration was initially high, and decreased significantly. The distribution of plasma free fatty acids remained unchanged. Platelet concentration was constant, whereas the percentage of reversible venous platelet aggregates initially was higher than in 11 healthy persons matched for age and sex. Platelet aggregates decreased transiently at 16 h. Venous reversible platelet aggregates correlated significantly with concentration of plasma free fatty acid, thus establishing a possible link between a change in lipid metabolism and platelet function. Plasma concentration of platelet factor 4 increased slightly but significantly during the initial hours. This may indicate an increased platelet release reaction.

Acute Disease↗
PubMed1976

Platelet consumption and plasma concentration of platelet factor 4 (PF-J).

In 10 cancer patients platelet concentration, platelet consumption, platelet half-life time and plasms concentrations of platelet factor 4 were determined. A high freguency of thrombocytosis and increased platelet consumption were observed, and the plasms concentrations of platelet factor 4 was increased. However, no significant correlation was found between platelet consumption and the result of a single determination of platelet factor 4 concentrations in plasma.

Adult↗
PubMed1975

The effect of noradrenalin infusion on plasma and platelet lipids and platelet function in man.

Noradrenalin was given as an intravenous infusion in a dosage of 0.1 mu-g/kg/h over a period of 30 minutes to 5 healthy male subjects. Blood samples were collected before, at the end of and 24 hours after the infusion. A significant increase in the number of circulating platelets and a marked increase of plasma FFA, reflecting an increase of all the main components of the FFA fraction were observed. No significant changes were observed in the similar lipid fraction in platelets and except for a moderate increase in platelet factor 3 activity, no significant changes in other platelet function tests were present.

Adult↗