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Biomedical subjects

G D Lowe

Publications and source records attributed to G D Lowe.

At least 307 records · Page 17Linked to original sources
PubMed1983

Relation of atrial fibrillation and high haematocrit to mortality in acute stroke.

Clinical and laboratory abnormalities and the presence of atrial fibrillation on admission were examined in relation to hospital mortality in a retrospective study of the 320 patients with acute stroke admitted to a medical unit in a 5-year period. Of clinical factors, only increasing age and the presence of coma were associated with mortality. Atrial fibrillation, present in 25% of all patients, was associated with an increased mortality in patients aged 60-79 years (67% vs 44%, p less than 0.01). In patients under 75 years the mortality associated with raised haematocrit (0.50 or more), present in 11% of all patients, was more than twice as high as it was in those with lower haematocrit (71% vs 31%, p less than 0.005). Other laboratory variables associated with a high mortality were increased levels of mean red cell volume, white cell count, erythrocyte sedimentation rate, globulin, and blood urea and creatinine; and decreased levels of albumin. The high prevalence of and increased mortality associated with atrial fibrillation and raised haematocrit in stroke patients indicate the need for further studies of stroke prevention and treatment in these patients.

Acute Disease↗
PubMed1983

Epoprostenol (prostacyclin) and severe arterial disease. A double-blind trial.

A 96 h infusion of epoprostenol (prostacyclin) or placebo was given as a treatment for rest pain to 28 patients with severe peripheral arterial disease. 24 h after the end of the infusion patients given epoprostenol had significantly less pain and took fewer analgesics tablets than did the controls. In some patients the epoprostenol effect lasted for over 1 month.

Arterial Occlusive Diseases↗
PubMed1983

Thromboembolic complications in Cushing's syndrome.

Thromboembolic events are thought to occur with increased frequency in Cushing's syndrome due to the predisposing factors, obesity, hypertension, a raised haematocrit and major surgery plus a 'hypercoagulable state'. To examine this postulate further we have studied 43 patients with Cushing's syndrome retrospectively and 10 patients prospectively to determine the incidence of arterial and venous thrombosis, both spontaneous and post-operative. Arterial events were noted in four cases (9%) and deep vein thrombosis or pulmonary thromboembolism (PTE) occurred in six cases (11%). Post-operative PTE occurred in 2.7% of all operations. These vascular complications tended to occur in the older patients with Cushing's syndrome. In our series, clinically significant thromboembolic episodes appear no more common than expected and the indications for prophylactic anticoagulation (the older and more obese patients) may not be different from other patients undergoing major surgery. An incidental finding was of a greater frequency of hypertension in Cushing's patients due to an adrenal adenoma.

Adrenalectomy↗
PubMed1983

Abnormal blood viscosity and haemostasis in long-standing retinal vein occlusion.

Blood viscosity and several haemostatic factors were measured in 42 patients with long-standing retinal vein occlusion and 33 control subjects. Blood viscosity, haematocrit, plasma viscosity, fibrinogen, fibrinopeptide A, and beta-thromboglobulin were increased in the 20 subjects with capillary nonperfusion or new vessels, but not in the 22 subjects without these complications. Patients with nonperfusion or new vessels also had a lower platelet count than patients without complications. Increased levels of factor VIII antigen and decreased levels of antithrombin III were found in the retinal vein occlusion group as a whole. These findings suggest that blood viscosity, platelets, and coagulation may be involved in retinal vein occlusion and its vascular complications.

Aged↗
PubMed1983

Coronary artery disease in severe haemophilia.

It has been suggested that the coagulation defect in haemophilia A protects these patients from coronary artery disease. We report two patients with severe haemophilia, who each had severe atheroma localised to the coronary arteries. Both patients had received only small amounts of factor VIII concentrates in their lifetime because of various social reasons. In one case death resulted from myocardial infarction secondary to an occlusive thrombus in a coronary artery. The implications of these findings to the pathogenesis of vascular disease are discussed.

Arteriosclerosis↗
PubMed1983

Contribution of the haematocrit to the bleeding time.

Bleeding time, platelet count and haematocrit were performed in 64 normal, anaemic and polycythaemic subjects with normal renal function and platelet counts over 100 X 10(9)/1. There was a significant inverse correlation between the bleeding time and haematocrit (r = -0.47) and an inverse correlation of the haematocrit and platelet count (r = -0.46). We suggest that the effect of the haematocrit on the bleeding time could explain the shorter bleeding time in men compared to women, and the shorter bleeding time in subjects with arterial disease, in whom an increased haematocrit is commonly found.

Adult↗
PubMed1983

Comparison of cerebral blood flow after venesection of bronchitic secondary polycythaemic and primary polycythaemic patients.

Cerebral blood flow was measured before and after lowering of haematocrit in four patients with primary polycythaemia and in nine with polycythaemia secondary to chronic obstructive airways disease. Cerebral blood flow values in each group were abnormally low to a similar degree at the start of the study and the degree of rise in cerebral blood flow per unit fall in haematocrit after venesection also was similar in each. Oxygen delivery fell despite increased cerebral blood flow and symptomatic benefit was infrequent. In male secondary polycythaemic patients rise in cerebral blood flow was not associated with any improvement in hypothalamo-pituitary-testicular function which we had previously noted to be suppressed in such hypoxic subjects. Our findings suggest viscosity changes rather than alteration in blood oxygen carriage to be responsible for cerebral blood flow improvement. It is concluded that therapeutic venesection in such patients should be applied with caution.

Adult↗
PubMed1983

Total knee arthroplasty in haemophilic arthritis.

The results of total knee replacement in five patients aged between 22 and 37 with severe haemophilia A or B are described. All patients had been managed conservatively without success. Frequent bleeds, severe pain and limitation of movement were the indications for operation. Despite close haematological surveillance, bleeding problems occurred in three of the patients and large quantities of plasma concentrates were required. Review of the patients over a period of 25 to 48 months after operation showed dramatic lessening of pain and maintenance of a satisfactory range of movement. The frequency of haemarthrosis diminished markedly and the requirements for factor concentrate in the years after operation fell substantially. Two patients returned to employment. Total knee replacement led to marked clinical improvement in all the patients, but the long-term results are not yet known.

Adult↗
PubMed1983

Blood viscosity in proliferative diabetic retinopathy and complicated retinal vein thrombosis.

Forty-two patients with longstanding retinal vein thrombosis and 36 patients with diabetes had their blood viscosity levels measured. In both conditions blood viscosity, plasma viscosity, and plasma fibrinogen levels were significantly higher in those patients with capillary non-perfusion and/or new vessels on fluorescein angiography, compared to those patients without these complications. The possible role of abnormal blood viscosity in producing capillary non-perfusion and its sequelae in both conditions is discussed.

Aged↗
PubMed1983

Bronchial carcinoma in von Willebrand's disease. Successful removal after hemostasis with lyophilized cryoprecipitate.

A man with severe von Willebrand's disease who had hemoptysis was followed-up for 2 1/2 years for continued hemoptysis and was discovered to have a bronchial carcinoma. Under close hematological surveillance, an uncomplicated pneumonectomy was performed, using a new factor VIII product--freeze-dried cryoprecipitate. This case illustrates that hemoptysis in von Willebrand's disease cannot always be attributed to the disease itself: that continued hemoptysis requires regular bronchoscopy and that major surgery can be performed in von Willebrand's disease with effective correction of the coagulation defect using freeze-dried cryoprecipitate.

Bronchial Neoplasms↗
PubMed1982

Effects of growth hormone, glucose and insulin on the factor VIII complex.

The relationship of growth hormone (GH) to the factor VIII complex (VIIIC, VIIIRAg and VIIIRRCo) was investigated. No correlation between basal levels of GH and factor VIII assays was found in 23 subjects. No significant change in factor VIII assays was observed after GH suppression by oral glucose or bromocriptine. After insulin-induced hypoglycaemic all three factor VIII assays rose and fell in parallel with GH. However, after exercise the rise in VIIIC and VIIIRAg preceded the rise in GH; and no changes in factor VIII assays were observed after administration of thyrotrophin releasing hormone (TRH) (releasing endogenous GH) or exogenous GH. These findings do not support a role for GH in the regulation of plasma levels of VIIIC, VIIIRAg or VIIIRRCo.

Antigens↗
PubMed1982

The effect of intramuscular stanozolol on fibrinolysis and blood lipids.

The effects of a single 50 mg intramuscular injection of the anabolic steroid stanozolol (Stromba) on fibrinolysis, blood coagulation and lipids was evaluated in 12 healthy male volunteers. Significantly increased plasminogen activator levels (p less than 0.05) was noted 24 hours following the injection and these remained elevated for one week. Plasminogen levels increased significantly by day two (p less than 0.01) and remained elevated for three weeks. HDL cholesterol fell (p less than 0.01) and both total and LDL cholesterol increased (p less than 0.05) when measured one month post injection. Stanozolol appears to have therapeutic potential as an activator of the fibrinolytic system when given by intramuscular injection.

Adult↗
PubMed1982

Factor IX thrombogenicity: in vivo effects on coagulation activation and a case report of disseminated intravascular coagulation.

An episode of defibrination with bleeding following high dose Edinburgh Factor IX (D.E.F.IX) replacement in a patient with haemophilia B undergoing knee joint replacement is reported. We have also monitored plasma fibrinopeptide A levels in patients with haemophilia B following ten standard doses of D.E.F.IX (15-20 u/kg) and have been unable to document any change. Activation of the coagulation system, as previously noted, appears to be related to the use of Factor IX concentrates in high doses.

Adult↗
PubMed1982

DDAVP stimulates prostacyclin production.

Des-amino-D-arginine vasopressin (DDAVP) stimulates the release of factor VIII and plasminogen activator from the vascular endothelium. An infusion of exogenous factor VIII given to haemophiliacs causes an increase in platelet activation. This activation does not occur after stimulating a rise in the patient's own factor VIII level caused by DDAVP infusion. We hypothesised therefore that DDAVP could also cause the endothelial release of prostacyclin (PGI2), a potent anti-platelet agent which would counteract the aggregating effect of factor VIII. To examine this possibility we studied the effect of DDAVP on prostacyclin release, as measured by its stable metabolite 6-oxo-PGF1 alpha, in vitro and in vivo. Rabbit aortic rings were incubated with different concentrations of DDAVP using saline as control. The supernatant was assayed for 6-oxo-PGF1 alpha by radioimmunoassay. All concentrations of DDAVP gave a significant release of 6-oxo-PGF1 alpha. Vasopressin was much less potent. When DDAVP was infused into haemophilic patients there was a significant increase in circulating 6-oxo-PGF1 alpha levels immediately after the infusion. The facial flushing observed as a side-effect of DDAVP could therefore be prostacyclin-mediated. We confirmed this by abolishing the DDAVP induced flushing seen in normal subjects by prior treatment with aspirin which inhibits PGI2 formation.

Animals↗
PubMed1982

Beta-thromboglobulin and platelet counts - effect of malignancy, infection, age and obesity.

Plasma levels of beta-thromboglobulin (BTG) and platelet count were studied in 69 control subjects, 19 patients with operable abdominal malignancy, and 9 patients with acute bacterial infection. In control subjects there was a significant rise in BTG and fall in platelet count with age, and a negative correlation of BTG with obesity. BTG and platelet count were normal in patients with operable malignancy, but significantly increased in patients with acute bacterial infection. These effects must be considered in studies of BTG and thrombosis.

Adult↗