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Biomedical subjects

M Halliwell

Publications and source records attributed to M Halliwell.

At least 55 records · Page 3Linked to original sources
PubMed1978

Antipyrine disposition and liver size in the elderly.

This study has examined the contribution of decrease in liver size to the decline in drug metabolising capacity which occurs with ageing. Liver volume and antipyrine kinetics were measured in two groups of healthy individuals aged 20 to 29 years and 75 to 86 years and in a group of hospitalised patients aged 70 to 89 years. Liver volume was reduced in both groups of elderly people compared to the young group. Antipyrine plasma half-life was prolonged and antipyrine clearance was reduced in the group of elderly normal individuals. In this group the index--antipyrine clearance per unit liver volume--was also reduced in comparison to that of the young group. Measurements of antipyrine elimination in the hospitalised elderly group did not differ significantly from those in the young group. It is concluded that both decreased liver mass and decreased hepatic enzyme activity contribute to the impairment of drug oxidation which occurs in the elderly and which may warrant a reduction in dosage of some drugs. However, differences have been demonstrated between groups of elderly people suggesting that under certain circumstances standard doses of such drugs may be normally tolerated.

Adult↗
PubMed1978

Effects of an oral contraceptive on hepatic size and antipyrine metabolism in premenopausal women.

Liver volume and antipyrine disposition have been investigated in healthy premenopausal women who received 30 microgram ethinyl oestradiol + 500 microgram dl-norgesterol as an oral contraceptive. Six months' treatment was associated with a 17% increase in liver volume while no change occurred in age-matched control subjects. In the same subjects the contraceptive decreased antipyrine clearance by 21%. Thus the contraceptive markedly reduced drug-metabolizing activity per unit volume of liver by 33%. In additional subjects, discontinuation of the contraceptive resulted in a 30% increase in antipyrine clearance. These observations confirm that conventional oral contraceptive therapy to premenopausal women increases hepatic size and that it is a potent inhibitor of drug-metabolizing activity.

Adolescent↗
PubMed1977

Sonographic demonstration of intrauterine contraceptive devices.

Ultrasonic examination of the uterus is the investigation of choice in the initial localization of an IUCD within the uterine cavity. The use of compound B scanning in conjunction with A scans has been completely reliable to date. Radiography should be reserved for those patients in whom an expected device is not shown within the uterine cavity, and for those in whom the determination of the type of device is important and the scan is equivocal.

Adult↗
PubMed1977

Tumour detection by ultrasonic Doppler blood-flow signals.

Ultrasonic Doppler blood-flow signals which seem to be associated with malignant tumour neovascularization have been detected in the female breast. No such signals have been detected from cysts. This discovery may lead to the development of a highspeed ultrasonic Doppler scanner which might make breast screening for cancer practicable.

Adenofibroma↗
PubMed1976

The relationship between liver volume, antipyrine clearance and indocyanine green clearance before and after phenobarbitone administration in man.

Liver volume and the clearances of antipyrine and indocyanine green have been measured before and after administration of phenobarbitone (180 mg/day) for 3 weeks to ten healthy subjects. The measurement of liver volume by an ultrasound scanning technique yielded reproducible results which were consistent with predictions of liver size by allometric methods. Before phenobarbitone, antipyrine clearance correlated with liver volume, but there was no correlation between indocyanine green clearance and liver volume. Phenobarbitone administration increased the clearance of antipyrine significantly by 90 +/- 14% but there was no significant change in indocyanine green clearance or liver volume. After phenobarbitone the correlation between antipyrine clearance and liver volume persisted. There was no correlation between indocyanine green clearance and liver volume. These results suggest that in non-medicated subjects some of the difference in antipyrine clearance is due to difference in functional hepatic parenchymal mass and that phenobarbitone increases the drug metabolising capacity per unit of hepatic mass but not total liver size.

Adult↗