Biomedical subjects

C Howie

Publications and source records attributed to C Howie.

At least 19 recordsLinked to original sources

PubMed1995

Helicobacter pylori infection and abnormalities of acid secretion in patients with duodenal ulcer disease.

BACKGROUND & AIMS: The mechanism by which Helicobacter pylori predisposes to duodenal ulcers (DUs) remains unclear. The aim of this study was to investigate the effect of the infection on acid secretion. METHODS: Acid output was examined basally and in response to gastrin-releasing peptide (GRP) and gastrin in healthy volunteers with and without H. pylori infection and in patients with DUs before and after eradication of the infection. RESULTS: Compared with H. pylori-negative healthy volunteers, patients with DUs with H. pylori had the following abnormalities of acid secretion: (1) threefold increase in basal acid output, (2) sixfold increase in acid response to GRP, (3) increased maximal acid response to exogenous gastrin, (4) increased ratio of basal acid output to maximal gastrin-stimulated output, and (5) increased ratio of maximal GRP-stimulated acid output to maximal gastrin-stimulated output. All of these abnormalities resolved fully after H. pylori eradication except for increased maximal acid output to gastrin, which was unchanged. Infected healthy volunteers showed a threefold increase in acid response to GRP that resolved after eradication of H. pylori infection. CONCLUSIONS: These disturbances in acid secretion caused by H. pylori infection are consistent with impaired inhibitory control and are likely to be relevant to the mechanism by which the infection predisposes to DU.

Amoxicillin↗

PubMed1992

Measurement of capillary cholesterol as an aid to the management of hypertensive patients with hyperlipidaemia--an assessment of the Reflotron.

The Reflotron dry chemistry method of capillary cholesterol measurement has been widely adopted as a rapid means of population screening. We attempted to use it to monitor changes in cholesterol in a trial of intensive dietary intervention in hyperlipidaemic hypertensives. Four hundred and eighty-nine capillary cholesterol levels measured by the Reflotron were compared with levels for venous samples obtained simultaneously and assayed by the Biochemistry Department using conventional laboratory methods. The mean difference between them was 0.3 mmol/l +/- 0.8 (SD). Approximately one-third of the variability in the difference between the two methods was explained by the variables, Reflotron machine used and time (R2 = 54%, adjusted R2 = 34%). We conclude that the Reflotron is not suitable for accurate assessment of the modest changes in cholesterol which occur in individual patients during dietary intervention.

Blood Chemical Analysis↗

PubMed1991

Measurement of capillary cholesterol in hyperlipidemia.

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Capillaries↗

PubMed1989

Skeletal muscle beta 2-adrenoreceptors and the effect of adrenergic drugs on plasma potassium in perinephritis hypertension in rabbits.

1. It has been suggested that beta 2-adrenoreceptors in skeletal muscle regulate plasma potassium. The possibility that alterations in the function and/or density of these receptors occurs in perinephritis hypertension in rabbits was studied. 2. Intravenous infusion of adrenaline (0.2 micrograms kg-1 min-1) caused a fall in potassium while intravenous bolus injection of propranolol (0.75 mg kg-1) resulted in an increase in serum potassium which was of similar magnitude in both perinephritis hypertensive and sham-operated normotensive rabbits. 3. Binding studies with the radioligand [125I] cyanopindolol (ICYP) showed that there were no significant differences between the hypertensive and normotensive rabbits in the density (Bmax) or affinity (KD) of the skeletal muscle beta 2-adrenoreceptor. 4. The results suggest that function and density of skeletal muscle beta 2-adrenoreceptors are not altered in rabbits with perinephritis hypertension.

Animals↗

PubMed1987

Sparing the flushes.

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Climacteric↗

PubMed1986

The effects of conjugated equine oestrogens with and without a cyclical progestogen on lipoproteins, and HDL subfractions in postmenopausal women.

Serum lipoprotein levels were followed for 24 weeks in 21 oophorectomised women treated with conjugated equine oestrogens (0.625 mg/day) and 21 women who had had a natural menopause and were treated with a combined preparation consisting of conjugated equine oestrogens (0.625 mg/day) with the addition of dl-norgestrel (0.15 mg/day) for the last 12 days of each treatment cycle. Conjugated equine oestrogens caused a significant (P less than 0.05) increase in triglyceride, HDL cholesterol, especially HDL2 cholesterol, and a significant decrease (P less than 0.05) in LDL cholesterol. Those subjects treated with conjugated equine oestrogens plus cyclical norgestrel showed a significant (P less than 0.05) decrease in LDL cholesterol levels only.

Cholesterol↗

PubMed1985

Pharmacodynamics and population pharmacokinetics of enalapril and lisinopril.

The di-acid metabolite of enalapril, enalaprilat, and its lysine analogue lisinopril are potent inhibitors of angiotensin converting enzyme (ACE); they do not contain sulphydryl groups. Both drugs can be assayed by high pressure liquid chromatography and by radioimmunoassay and plasma ACE inhibition remains stable under normal storage conditions. It is therefore possible to study their pharmacokinetics as well as their pharmacodynamic effects in man. Enalaprilat and lisinopril as well as ACE activity have been measured in blood taken during the course of two studies of the effects of these drugs on blood pressure and autonomic responsiveness. A population pharmacokinetic analysis approach applied to a few concentration-time data points in each of a relatively large number of subjects provided average population parameter estimates of the absorption rate constant, volume of distribution and clearance which correspond closely with the limited published data based on conventional pharmacokinetic approaches. It also provided estimates of pharmacodynamic parameters and the concentration of the drug required to produce a 50% ACE inhibition. Population drug concentration data obtained in the course of early clinical evaluations of new drugs may provide a rational basis for dosage regimens with improved efficacy and, in particular, reduced concentration-related toxic effects.

Adult↗

PubMed1984

Ten years post-menopausal hormone replacement therapy--effect on lipoproteins.

Serum lipoproteins were measured in 72 post-menopausal women, 40 of whom had been taking the synthetic oestrogen, mestranol, for a period of 10 yr and 32 of whom had been taking identical placebo tablets. Mestranol therapy was found to increase serum triglycerides, decrease low density lipoprotein (LDL) cholesterol and increase high density lipoprotein (HDL) cholesterol. The increase in HDL cholesterol was due principally to a marked increase in the cardioprotective HDL2 fraction. It is concluded that long-term mestranol therapy has a beneficial effect on serum lipoproteins which may help to protect post-menopausal women against fatal ischaemic heart disease.

Cholesterol↗

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