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Biomedical subjects

C R Prentice

Publications and source records attributed to C R Prentice.

At least 109 records · Page 6Linked to original sources
PubMed1981

Prevention of deep vein thrombosis in medical patients by low-dose heparin.

A randomised trial was undertaken in one hundred patients with heart failure and/or chest infection to determine whether low-dose subcutaneous heparin induced the frequency of deep vein thrombosis (DVT) in the legs. Heparin, (5000 units 8 hourly) significantly reduced the frequency of DVT, diagnosed by the 125I-fibrinogen scan technique, from 26 to 4 per cent (p less than 0.01). Heparin was started within 12 hours of admission to hospital and continued until the patient was fully mobile. Heparin did not cause bleeding problems except for a 20 per cent incidence of injection site bruising. We therefore recommend prophylaxis with low-dose subcutaneous heparin in patients with heart failure or chest infection who require more than three days bed rest.

Aged↗
PubMed1980

Relation between extent of coronary artery disease and blood viscosity.

Blood viscosity (shear rate 100/s) and its major determinants (packed cell volume, plasma fibrinogen concentration, and plasma viscosity) were measured before coronary angiography in 50 men aged 30-55 and related to the extent of coronary artery disease. Twenty-six men had extensive disease (stenosis of two or three major coronary vessels), and 24 had either stenosis of one vessel or no stenosis. The 26 men with extensive disease had significantly higher mean blood viscosity than those with mild or no disease and 25 healthy controls (p less than 0.001). The increased viscosity was due partly to a higher packed cell volume and partly to a higher fibrinogen concentration; plasma viscosity was not significantly increased. These differences could not be explained by smoking history. These results suggest an association between increased blood viscosity and extensive coronary artery disease in men, which merits further investigation.

Adult↗
PubMed1980

Comparison of Pasteur and Behringwerke antivenoms in envenoming by the carpet viper (Echis carinatus).

Bites and envenoming by the carpet viper Echis carinatus are common medical emergencies in parts of Nigeria, but the most effective use of the various commercially produced antivenoms in treatment has not been established. Pasteur Paris Echis monospecific and Behringwerke West and North Africa Bitis-Echis-Naja polyspecific antivenoms were compared in two groups of seven patients with incoagulable blood after E carinatus bites. In both groups spontaneous bleeding stopped within a few hours and local swelling subsided within two weeks after the initial antivenom injection. Pasteur antivenom (20-40 ml) restored blood coagulability within 12 hours in all cases, but 60--180 ml of Behringwerke antivenom was effective in only four cases. Persisting venom procoagulant activity was observed in the remaining three cases. Despite its potency in the mouse protection test, Behringwerke antivenom is unreliable and unpredictable in neutralising venom procoagulant in humans bitten by E carinatus.

Adult↗
PubMed1980

Low dose heparin in the prevention of deep-vein thrombosis after aortic bifurcation graft surgery.

In a randomised double-blind controlled trial 24 patients undergoing elective aortic bifurcation graft surgery received subcutaneous calcium heparin (2,500 u pre-operatively then 5,000 u 12-hourly for 7 days) and 25 control patients received saline injections. All patients received a routine dose of intravenous sodium heparin intra-operatively. The trial was terminated because of excess bleeding complications in patients receiving subcutaneous heparin (8 vs. 1, p less than 0.05). Deep vein thrombosis occurred in 6 control patients and 2 patients on heparin (p less than 0.05). In this group of patients undergoing major vascular surgery the risk of bleeding due to heparin outweighed the potential benefit of thrombotic prophylaxis.

Aorta↗
PubMed1980

Increased plasma fibrinogen and platelet-aggregates in type II hyperlipoproteinaemia.

Plasma fibrinogen and platelet-aggregates (method of Wu and Hoak) were measured in 21 patients with familial Type II hyperlipoproteinemia and 21 matched control subjects. Patients with hyperlipoproteinaemia had increased levels of fibrinogen and platelet-aggregates (p less than 0.01). Young patients with hyperlipoproteinaemia had prematurely high fibrinogen levels, and the normal rise in fibrinogen during adult life was abolished. There were no statistically significant correlations within the patient group between fibrinogen, platelet-aggregates, and plasma lipids. High fibrinogen and platelet-aggregate levels may play a part in the development of the premature arterial disease associated with Type II hyperlipoproteinaemia, or may be markers of arterial injury.

Adolescent↗
PubMed1980

The structure of soluble fibrin complexes and fibrin degradation products after Echis carinatus bite.

Studies on the concentration and structure of fibrinogen, fibrinogen-fibrin soluble complexes, and fibrinogen-fibrin degradation products were made on 11 patients in Nigeria who suffered defibrination following Echis carinatus bite. Following admission, before treatment with antivenom, all patients had reduced or zero fibrinogen levels, and increased concentrations of soluble complexes and degradation products. The fibrin component of the soluble complexes, separated by fibrinogen-sepharose chromatography, consisted of both intact fibrin and fibrin degraded at the alpha-chain. After isolation by Biogel chromatography the soluble complexes were also found to contain gamma-dimer chains. The fibrinogen-fibrin degradation products consisted of several X species, Y, D and D-dimer, as well as fragment E. The major fragment in all patients was D, but a few samples contained significant quantities of D-dimer, indicating in vivo activation of factor XIII. There was evidence of degraded fibrinogen, as well as fibrin, in the soluble complexes and degradation products, suggesting that fibrinogenolysis, in addition to fibrinolysis, had occurred, probably as a result of secondary endogenous activation of the fibrinolytic system in response to defibrination.

Antivenins↗
PubMed1980

Factor VIII related antigen/coagulant activity ratio as a predictor of fetal growth retardation: a comparison with hormone and uric acid measurements.

Factor VIII related antigen (VIIIRAg), Factor VIII coagulant activity (VIIIC), plasma uric acid, total plasma oestriol, plasma human placental lactogen (hPL) and urine oestrogen/creatinine ratio were measured in a group of 21 patients clinically suspected of fetal growth retardation and compared with normal pregnancy. Of the hormone assays, hPL was better than either oestrial or oestrogen/creatinine ratio at distinguishing between normal and growth retarded pregnancies. Uric acid levels tended to be higher than normal in patients with fetal growth retardation, but the best means of distinguishing normal from growth retarded pregnancies proved to be the VIIIRAg/VIIIC ratio. This ratio was significantly elevated in fetal growth retardation compared with normal pregnancy, and the increase was evident as early as 30 weeks gestation. Using the VIIIRAg/VIIIC ratio test, the outcome of 17 of the 21 suspect pregnancies could be correctly predicted.

Antigens↗
PubMed1979

Renal function and other factors in obstructive jaundice.

Renal function and other factors that possibly affect the outcome of operation were measured in 24 patients with obstructive jaundice and in 15 non-jaundiced controls. The preoperative features that were associated with a poor postoperative recovery from obstructive jaundice were a raised serum fibrinogen/fibrin degradation product concentration, infection, hypoalbuminaemia and a low glomerular filtration rate. Preoperative serum fibrinogen/fibrin degradation product concentrations were raised in 4 of the 6 jaundiced patients who died after surgery but in none of the controls, in whom there was no mortality. In the jaundiced patients there was a greater incidence of postoperative renal impairment than in the controls. All patients were given mannitol during operation. Further mannitol was required after surgery in 13 of the 24 jaundiced patients in order to maintain urine flow rate despite adequate intravenous fluids being given. In contrast, only 1 of the 15 control patients required post operative mannitol. It is emphasized that repeated doses of mannitol can lead to a profound natriuresis and adequate intravenous saline should be given.

Cholestasis↗