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Biomedical subjects

J F Davidson

Publications and source records attributed to J F Davidson.

At least 73 records · Page 4Linked to original sources
PubMed1980

Maintenance control of oral anticoagulant therapy by a chromogenic substrate assay for factor X.

An amidolytic assay employing the chromogenic substrate S 2337 (Kabi Diagnostica) was used to assay factor X in 35 healthy controls and in 100 outpatients receiving oral anticoagulant therapy. This method correlated well with a coagulation assay of factor X in the control group (r = 0.88). When compared with two routine tests for the control of anticoagulant theray (Thrombotest and prothrombin ratio) good correlation was obtained between the methods, r = 0.84 and r = -0.74 respectively. These results suggest that a chromogenic substrate assay for factor X might be a suitable method for the maintenance control of oral anticoagulant therapy.

Adult↗
PubMed1978

Preparation and evaluation of an antiserum to the carboxymethylated Aalpha chain of human fibrinogen.

Antiserum to the carboxymethylated Aalpha chain of human fibrinogen has been produced in rabbits and its reactions investigated in a double diffusion system. The antiserum reacts with the carboxymethylated Aalpha chains, but not with carboxymethylated gamma chains, nor with carboxymethylated Bbeta chains, provided that the antiserum had been absorbed with carboxymethylated Bbeta chains. The antiserum also reacts with Aalpha chains in the whole fibrinogen molecule, either in plasma or in the purified form, and spur formation was observed when intact fibrinogen was compared with high solubility fibrinogen, which contained little or no intact Aalpha chain.

Animals↗
PubMed1977

Oral contraceptive use and venous thromboembolism: absence of an effect of smoking.

We conducted a case-control study to test the hypothesis that women smokers who use oral contraceptives have an increased risk of developing venous thrombosis. Patients and controls were drawn from two sets of hospital patients already included in the Boston Collaborative Drug Surveillance Programme. Sixty patients with uncomplicated thromboembolism were matched with 180 controls with other diagnoses; all were premenopausal women taking oral contraceptives. Patients with conditions that might predispose to thromboembolism or be related to smoking were excluded. We found no association between smoking habits and thromboembolism. Similarly, we found no association between thromboembolism, smoking, and duration of oral contraceptive use. Thus we conclude that differences in fibrinolytic activity between smokers and non-smokers are not major factors in the aetiology of uncomplicated thromboembolism in women using oral contraceptives.

Clinical Trials as Topic↗
PubMed1977

Haematological abnormalities in acute pancreatitis. A prospective study.

Twenty-five patients with acute pancreatitis were studied prospectively in the first week of their admission using haematological and coagulation tests. Platelet counts initially fell and later returned to admission levels. Rising levels of plasma fibrinogen were recorded. The kaolin cephalin clotting time was shorter than its control in twenty-one patients. Eighteen patients had elevated fibrinogen degradation products and fourteen had a positive ethanol gelation test. It is suggested that by taking into account the results in series of individual patients a degree of intravascular coagulation may be a common feature of acute pancreatitis. In one patient (presented in detail) strong evidence for disseminated intravascular coagulation was found

Acute Disease↗
PubMed1976

Application of polarization effects in light scattering: a new biophysical tool.

We demonstrate that a newly developed instrument which measures all polarization and intensity information contained in differentially and elastically scattered light has valuable applications in biology. The polarization states of light scattered differentially from suspensions of biological scatters are shown to contain structural information about those systems. The scatterers are discussed in the context of a 16 component matrix which completely characterizes the scattering process. The instrument and method are described in terms of the corresponding matrix algebra. We also discuss the use of the instrument as a device for distinguishing between closely related structural systems and as a tool for following time-dependent structural changes.

Bacillus subtilis↗
PubMed1975

Plasma fibrinolytic activity following oral anabolic steroid therapy.

Six anabolic steroids were assessed for their ability to enhance plasma fibrinolytic activity in males with ischaemic heart disease. Five 17alpha-alkylated steroids (Ethyloestrenol, Norethandrolone, Methandienone, Methylandrostenediol and Oxymetholone) were examined and all produced a significant increase in plasma plasminogen activator as measured by the euglobulin lysis time. The only non-17alpha-alkylated steroid studied (Methenolone acetate) failed to enhance fibrinolysis. The 17alpha-alkylated steroids studied all deserve more detailed evaluation of their long term effects on plasma fibrinolytic activity.

Adult↗
PubMed1975

Effect of anabolic steroids on plasma antithrombin III. alpha2 macroglobulin and alpha1 antitrypsin levels.

The effect of seven different anabolic steroids (Ethyloestrenol, Methenolone acetate, Norethandrolone, Methylandrostenediol, Oxymetholone, Methandienone, and Stanozolol) on three alpha-globulin antiprotease inhibitors of thrombin and plasmin was studied in men with ischaemic heart disease. In distinct contrast to the oral contraceptives, five of the six 17-alpha-alkylated anabolic steroids studied produced increased plasma Antithrombin III levels and five produced decreased levels of plasma alpha2-macroglobulin. The effect on plasma alpha1-antitrypsin levels was less clear-cut but three of the steroids examined produced significantly elevated levels. The increased plasma fibrinolytic activity which the 17-alpha-alkylated anabolic steroids induce is therefore unlikely to be secondary to disseminated intravascular coagulation.

Adult↗