PubMed Health⌕ Search

Biomedical subjects

A Grennan

Publications and source records attributed to A Grennan.

6 recordsLinked to original sources
PubMed1990

Platelet and plasma vasoactive amines in type 1 (insulin-dependent) diabetes mellitus with and without vascular disease.

Platelet and plasma vasoactive amine concentrations were measured in healthy controls and in type 1 (insulin-dependent) diabetic patients with or without vascular disease. Platelet concentrations of serotonin and noradrenaline were similar in all groups and were unrelated to age or gender, or to duration of diabetes, blood pressure, glycaemia or renal function in the diabetic subjects. Plasma concentrations of serotonin in the diabetic groups were comparable (118 +/- 16 (mean +/- SEM) and 127 +/- 21 pmol/mL), and were significantly higher in comparison to the healthy controls (66 +/- 12 pmol/mL, P = 0.002).

Adolescent↗
PubMed1989

Platelet serotonin in systemic sclerosis.

Platelet serotonin concentrations were measured in 43 patients with systemic sclerosis, in 11 patients with primary Raynaud's phenomenon, and in 38 normal controls. Patients with the CREST variant (calcinosis, Raynaud's phenomenon, oesophageal dysmotility, sclerodactyly, telangiectasia) had significantly lower platelet serotonin concentrations than normal controls. Patients with diffuse systemic sclerosis had normal platelet serotonin concentrations. In patients with CREST treatment with ketanserin, a specific serotonin antagonist, normalised platelet serotonin concentrations. These data provide further evidence suggesting that in systemic sclerosis, particularly the CREST variant, there is widespread platelet activation.

Adult↗
PubMed1987

Bioavailability of bumetanide in grossly oedematous patients.

A pharmacokinetic study was undertaken to determine the bioavailability of bumetanide in grossly oedematous patients. Six nephrotic patients were administered bumetanide 2mg orally (as tablets) and intravenously as single doses, in a randomised fashion. Serum bumetanide concentration-time profiles were characterised. Data were fitted to a 2-compartment model (5 patients) and a 3-compartment model (1 patient). Analysis of the areas under the curves showed a bioavailability of 0.84 +/- 0.2, which is similar to that in normal individuals. It is suggested that the bioavailability of oral bumetanide in oedematous patients is not altered significantly and that the apparent resistance to diuretics in such patients may be due to another cause.

Aged↗
PubMed1987

Ascorbic acid as an antioxidant in measurements of catecholamines in plasma.

Sodium metabisulfite, commonly used to prevent the oxidation of catecholamines during extraction from plasma onto alkaline alumina, does not prevent their subsequent degradation in acetic acid eluates. However, ascorbic acid, a potent antioxidant, is extracted with the catecholamines onto the alumina and prevents such destruction. However, ascorbic acid may interfere with the electrochemical measurement of catecholamines, unless sequential oxidation and reduction are used. Other methods of minimizing catecholamine oxidation in acetic acid eluates include refrigerating at 4 degrees C and capping the sample vials to exclude atmospheric oxygen.

Aluminum Oxide↗
PubMed1979

In-vitro reactions of lymphocytes in rheumatoid arthritis and other rheumatic diseases.

Various lymphocyte functions and the percentage of different subpopulations have been measured in groups of patients with seropositive rheumatoid arthritis, seronegative ankylosing spondylitis, and psoriatic arthritis, Sjögren's syndrome, sicca complex, and in normal controls. Several abnormal results were found--in the responses to mitogens, in the antibody-dependent cytotoxic test, and in the percentages of EA rosettes (antibody sensitised chick red cells test) and surface immunoglobulin-bearing cells. In the light of these findings cytotoxicity and lymphocyte subpopulations were measured in further groups of rheumatoid arthritis patients in whom the disease was at different stages. The results showed that the changes in cytotoxic potential occurred in patients with active arthritis. Correlation tests showed significant positive associations between the percentage of SE rosette-forming cells (sheep red cells test) and the mitogenic responses to phytohaemagglutinin and concanavalin A, and between the percentage of EA rosette-forming cells and the levels of antibody-dependent cytotoxicity. The results are discussed in the light of our understanding of cellular subpopulations in the immune system.

Adolescent↗