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Biomedical subjects

C Irwin

Publications and source records attributed to C Irwin.

35 records · Page 2Linked to original sources
PubMed1988

Antihypertensive efficacy of cetamolol: a dose-titrated study.

This double-blind, placebo-controlled, randomized multicenter study evaluated the antihypertensive efficacy and safety of cetamolol hydrochloride in 108 patients diagnosed as having mild to moderate hypertension. After a placebo lead-in period, patients received either cetamolol 5-10-15 mg/d (low dose), cetamolol 15-25-50 mg/d (high dose), or placebo, once daily for four weeks. Patients began at the lowest dose and were titrated to higher doses based on the first two assessments of diastolic blood pressure and heart rate, which were conducted each week after double-blind treatment was dispensed. After four weeks of treatment 82.4%, 81.3%, and 93.3% of the low-dose group, high-dose group, and placebo group, respectively, were titrated to the maximum dose level. After four weeks of treatment and 24 hours since the patient's last dose, both cetamolol groups showed a significantly greater (P less than or equal to .05) reduction in supine systolic/diastolic blood pressure (-18.1 +/- 2.3/-9.2 +/- 1.5 mm Hg [low dose] and -17.3 +/- 2.3/-8.3 +/- 1.6 mm Hg [high dose]) than the placebo group (-9.9 +/- 2.5/-3.5 +/- 1.7 mm Hg). In general, the changes in standing (stabilized) systolic and diastolic blood pressure were similar to those seen in supine measurements. Significantly more patients receiving cetamolol than those receiving placebo showed a "good response" (a decrease in diastolic blood pressure of 10 mm Hg or more or measuring less than 90 mm Hg with a decrease of at least 4 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetamides↗
PubMed1988

Cardioselectivity of cetamolol compared with atenolol and nadolol.

The selectivity of the beta-adrenoceptor blockade produced by single oral doses of cetamolol, atenolol, and nadolol was compared in normal male subjects. Study 1 established the dose at which each drug provides equivalent beta-1 blockade. Beta-1 blockade was estimated using the degree of inhibition of the increased heart rate (HR) response to graded exercise. Cetamolol (30 mg), atenolol (100 mg), and nadolol (80 mg) all attenuated the HR response to a comparable extent. This result established that the dose ratio of cetamolol:atenolol:nadolol of 1.00:3.33:2.67 provides equipotent beta-1 blockade. This ratio of doses was used in Studies 2 and 3 to evaluate the antagonism of beta-2-mediated responses to titrated doses of intravenous isoproterenol (ISO) by low and high doses of each drug. Beta-2 blockade was assessed using the attenuation of ISO-induced reductions in diastolic blood pressure (DBP) in Study 2 and ISO-induced increases in specific airway conductance (sGAW) in Study 3. For within drug comparisons, antagonism of the HR increase induced by ISO (a response mediated by both beta-1 and beta-2 receptors) was also examined. Treatments included cetamolol (15 and 60 mg), atenolol (50 and 200 mg), and nadolol (40 and 160 mg in Study 2; 40 mg only in Study 3). All drugs tested suppressed the HR, DBP, and sGAW responses to ISO, and this blockade was dose dependent. Cetamolol and nadolol produced approximately equipotent beta-1 blockade, whereas cetamolol at both doses produced a less potent beta-2 blockade. Atenolol antagonized ISO effects on all parameters less than either cetamolol or nadolol. Quantitative cardioselectivity indices revealed that cetamolol 60 mg was the most cardioselective and nadolol 40 mg the least. Data from the three studies demonstrate that cetamolol is cardioselective relative to nadolol and that, in contrast to atenolol, cardioselectivity appears to increase at the higher dose.

Acetamides↗
PubMed1988

Effect of cetamolol on epinephrine-induced hypokalemia.

The effect of cetamolol (an investigational cardioselective beta blocker with intrinsic sympathomimetic activity) on the hypokalemic response to epinephrine infusions in normal subjects was evaluated and compared with placebo and two other beta-adrenergic blocking drugs. After two daily doses of cetamolol 15 mg, atenolol (a cardioselective beta blocker) 50 mg; a long-acting propranolol preparation (a nonselective beta blocker) 80 mg; or placebo, 12 men (mean age, 26.7 years) were infused with epinephrine. The resulting average plasma epinephrine level was 1123 pg/mL, whereas average baseline serum potassium levels for the four treatment groups ranged from 3.94 to 4.07 mEq/L. Epinephrine-induced hypokalemia occurred in the placebo group (maximum potassium decrease of 1.00 mEq/L) and in the atenolol group (maximum potassium decrease of 0.59 mEq/L); potassium levels did not decrease but rose slightly in subjects receiving cetamolol or propranolol. Subjects treated with placebo or atenolol also demonstrated statistically significant prolongation of the QTc interval (0.039 seconds with placebo; 0.023 seconds with atenolol) and frequently developed T-wave flattening and U-wave appearance. After pretreatment with cetamolol or propranolol, however, the QTc interval was unaffected, T-wave abnormalities did not occur, and U waves appeared only rarely. The results of this study indicate that cetamolol blocks epinephrine-induced hypokalemia and associated electrocardiographic changes.

Acetamides↗
PubMed1987

A longitudinal study of the psychological morbidity in children due to a natural disaster.

This longitudinal study examined the psychological impact of a bushfire disaster on a group of 808 children aged from 5 to 12. Contrary to prediction, the prevalence of behaviour and emotional problems 2 months after the fire was less than the prevalence in a carefully selected comparison group. Rather than decrease with time, the prevalence of psychological morbidity increased significantly, being as great 26 months after the disaster as at 8 months.

Australia↗
PubMed1986

The dying child.

Explore the source record for details and available documents.

Adolescent↗
PubMed1976

Monamine oxidase in outer membrane of skeletal muscle mitochondria.

(1) Monoamine oxidase (EC 1.4.3.4) is present in rat skeletal muscle mitochondria. (2) A radioassay procedure for the assay of monoamine oxidase in muscle mitochondria is described. It is based on teh procedure using side-chain [2-14C]-tryptamine as substate described by Wurtman, R.J. and Axelrod, J. (1963) Biochem. Pharmacol. 12, 1439--1441 and employs a pH of 8.0 and a substrate concentration of 0.25 mM. (3) The Km of the muscle mitochondrial enzyme at pH 8.0 is 1.34 - 10(-5) M and that of the liver enzyme under the same conditions is 2.5 - 10(-5) M. Muscle mitochondria contain only one quarter of the activity of enzyme present in liver mitochondria. (4) Monoamine oxidase is shown to be in the outer membrane of skeletal muscle mitochondria and thus to be a suitable marker enzyme for use in the fractionation of these mitochondria.

Animals↗
PubMed1975

The establishment of a child abuse unit in a children's hospital.

The recognition of the child abuse syndrome in the Republic of Sout Africa is briefly mentioned. The aims of setting up a Child Abuse Unit in a children's hospital are detailed; the procedure for the education of staff, details of training and the establishment of a programme are outlined, and the outcome is considered. The co-operation of the medical profession is sought in setting up programmes for the prevention of child abuse.

Adolescent↗