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Biomedical subjects

M Papouchado

Publications and source records attributed to M Papouchado.

42 records · Page 3Linked to original sources
PubMed1985

Pacing failure due to flecainide acetate.

Flecainide acetate is a recently introduced, class 1 antiarrhythmic agent that is highly effective in the treatment of ventricular and atrioventricular/nodal reentrant tachycardias. Although both intravenous and orally administered flecainide are known to cause an increase in the pacing threshold, an abrupt and potentially lethal rise in threshold causing failure of a properly functioning, newly implanted pacing system has not to our knowledge been described. We report such a case to stress the need for caution when using this drug in elderly pacemaker patients.

Aged↗
PubMed1985

Efficacy of transdermal glyceryl trinitrate in the treatment of chronic stable angina pectoris.

A study was carried out to assess the efficacy of a new transdermal preparation of glyceryl trinitrate (Transiderm-Nitro 5) in the 24 hour prophylaxis of angina and to determine the duration of effect of a single patch application. Twelve men with chronic stable angina were studied in a randomised, placebo controlled, double blind trial. By serial treadmill exercise testing a therapeutic effect was shown at three hours; the exercise time to angina and to 1 mm ST segment depression and the total exercise time were all significantly increased. At 24, 48, and 72 hours, however, no therapeutic effect was observed. Recent studies have shown a similar lack of effect at 24 hours for various forms of transdermal delivery systems. It is suggested that this lack of effect is due to the rapid onset of tolerance probably as a result of the constancy of blood concentrations obtained by this method of administration.

Administration, Topical↗
PubMed1980

Carbenoxolone interactions in man--preliminary report.

Carbenoxolone is a potent ulcer-healing drug which is extensively bound to plasma proteins and therefore has the potential for displacement interaction. However, carbenoxolone has been shown to be bound to human serum albumin in vitro at a different class of binding site to many other drugs and does not potentiate the pharmacological activity of warfarin, tolbutamide, chlorpropamide or phenytoin in the rat. In the present study four volunteers each received a single 100 mg dose of Biogastrone and the plasma half-life of carbenoxolone was determined. The procedure was repeated with a concurrent dose of either warfarin 10 mg, tolbutamide 500 mg, chlorpropamide 250 mg or phenytoin 100 mg. Chlorpropamide appeared to delay the absorption of carbenoxolone but no effects were observed with the other drugs. The study with concomitant chlorpropamide treatment was repeated with 6 gastric ulcer patients on an established Biogastrone regimen. In these patients the delayed absorption of carbenoxolone was confirmed although no changes in the glucose-lowering activity of chlorpropamide were evident. Further investigations into this findings are in progress.

Carbenoxolone↗
PubMedDate not supplied

Measurement of single-breath carbon monoxide transfer factor (diffusing capacity) during progressive exercise.

The transfer factor (diffusing capacity) for carbon monoxide (TLCO) is known to rise with increasing levels of work, but uncertainty remains as to the exact relationship of TLCO and the transfer coefficient (KCO) to oxygen uptake (VO2). We have studied the effects of increasing levels of work on TLCO and KCO in 22 normal male subjects using the single-breath technique and a standardized protocol. Additionally, we have investigated whether young people were different from a middle-age group, the need for carboxyhaemoglobin corrections in current smokers and non-smokers, and the variations of cardiac frequency during breath-holding. Our results show that TLCO and KCO increase in a curvilinear manner up to maximal VO2, a quadratic equation describing the relationship. There was no effect of age up to 50 years. There was no significant increase in the carboxyhaemoglobin levels, and therefore this correction is unnecessary. Cardiac frequency showed no significant variation during the breath-holding manoeuvre, except at rest and at low levels of exercise.

Adult↗