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Biomedical subjects

J Nicholl

Publications and source records attributed to J Nicholl.

13 recordsLinked to original sources
PubMed1992

Interactions between hypoxic and almitrine-induced vasoconstriction in the rat lung.

1. To test whether almitrine might improve the arterial partial pressure of O2 in patients with chronic obstructive airways disease by improvement of ventilation-perfusion matching, we looked at the interaction between hypoxic and almitrine-induced vasoconstriction in isolated rat lungs perfused with blood at constant flow. Increases in pressure represented increases in resistance. 2. Almitrine, given in increasing doses between challenges with 2% O2, enhanced hypoxic vasoconstriction at low doses but attenuated it at high doses. 3. Stimulus-response curves to hypoxia of increasing severity gave a sigmoid curve. 4. Almitrine solvent caused small changes in pulmonary artery pressure and shifted the stimulus-response curve slightly in a parallel fashion. 5. Small doses of almitrine enhanced the action of mild to moderate hypoxia, medium doses attenuated moderately severe hypoxia, whereas high doses depressed vasoconstriction due to all degrees of hypoxia. 6. These effects of almitrine on hypoxic vasoconstriction were compared with the effect of solvent by analysis of variance; the results substantiated significant enhancement of hypoxia by small doses and attenuation by large doses. 7. In patients, if similar effects apply, small doses of almitrine would assist ventilation-perfusion matching, but large doses might worsen it. 8. Almitrine-induced vasoconstriction was attenuated by a fall in perfusate temperature in a similar manner to hypoxic vasoconstriction. It was also attenuated by three drugs, chlorpheniramine, propanolol and diethylcarbamazine, all of which also decrease hypoxic vasoconstriction. The similarity between hypoxic and almitrine-induced pulmonary vasoconstriction is further confirmed.

Almitrine↗
PubMed1991

Enlargement of circumscribed choroidal hemangiomas.

The authors describe five patients with circumscribed choroidal hemangiomas. Fundus photography, fluorescein angiography, and ultrasound examinations showed progressive enlargement of these hemangiomas. In all cases, the extent of lesion enlargement was slight: the mean change in tumor size was 1.6 mm x 1.5 mm in basal diameters by 0.9 mm in thickness during a median interval of 52 months (range 33 to 100 months) between initial tumor diagnosis and detection of lesion enlargement. This series of cases demonstrates that circumscribed choroidal hemangiomas can enlarge slightly during long intervals between observations.

Adolescent↗
PubMed1989

Estimates of general practitioner workload: a review.

This paper reviews four studies sponsored by the Department of Health which have attempted to measure workload in general practice and compares these with data from the general household survey. Despite the considerable differences in the objectives and methods employed by the four studies, they were found to contain remarkably consistent measurements of general practitioner workload. In a 'normal working week' general practitioners spend 38 hours on general medical service duties (including 24 hours of patient contact and five hours of travel to home visits), they see 150 patients or their representatives in surgery, and make 26 home visits. In an 'annual average week', taking into account holidays and sick leave, general practitioners undertake 90% of this workload. The studies show consistently large variations in the workload of general practitioners measured in this way, but fail to identify the key determinants of such variations. The reasons underlying the variation in general practitioner workload will remain unclear until we can distinguish between the expected, measurable variation and the residual, unexplained variation which may be due to the personal preferences of general practitioners.

Appointments and Schedules↗
PubMed1988

Revising RAWP.

Explore the source record for details and available documents.

England↗
PubMed1986

Sedation for gastroscopy: a comparative study of midazolam and Diazemuls in patients with and without cirrhosis.

A double-blind controlled study comparing the effects of intravenous Diazemuls (0.15 mg kg-1) with midazolam (0.07 mg kg-1) in patients with normal liver function and with cirrhosis and portal hypertension is described. The clinical effect of the two drugs was assessed by serial tests of psychomotor function before and at varying intervals after administration. Using this dosage regime, midazolam caused significantly greater impairment in psychomotor function in both cirrhotic and non cirrhotic subjects, and the time taken for recovery of normal function was also significantly prolonged. Patients with cirrhosis showed a significantly prolonged recovery time following administration of either benzodiazepine compared with the controls. Administration of midazolam in a lower dose might reduce the degree of sedation and shorten the recovery time, but this could also lead to a loss of some of the amnesic effect. Caution is recommended in the administration of benzodiazepines to patients with cirrhosis.

Adult↗
PubMed1985

Chloroquine retinopathy. Is fluorescein angiography necessary?

Color fundus photographs and corresponding fluorescein angiograms from 83 patients suspected of having chloroquine retinopathy were reviewed in a retrospective masked study to determine the relative sensitivity of these two photographic methods in the diagnosis of retinal toxicity. We identified retinal toxicity on both color photographs and fluorescein angiograms in 7.6% of cases, on the color photographs but not on the corresponding angiograms in 6.1% of cases, and on the fluorescein angiograms but not on the color photographs in 1.5% of cases. Fluorescein angiography may not be as sensitive as color fundus photography (or ophthalmoscopy) in the diagnosis of chloroquine retinopathy.

Chloroquine↗
PubMedDate not supplied

Double-blind controlled trial of prostacyclin in cerebral infarction.

Thirty-two patients with acute cerebral infarction received either prostacyclin or placebo intermittently for 65 hours. Pulse and blood pressure were not altered by prostacyclin. After infusion there was no change in infarct volume or cerebral blood flow in either group. After normalisation for starting values, age and site of cerebral infarction there was a greater than 10% improvement in speech in the prostacyclin group, but minimal changes in neurological score or disability status. Age is related to neurological score at 14 days after stroke by decreasing improvement by 6.8% for each additional 10 years. This study has not been able to demonstrate that prostacyclin is effective in the treatment of ischaemic stroke, but due to the sample size the chance of proving this statistically (the power) was small. Similarly any conclusion that prostacyclin is not effective may be wrong because of the Type II error probability being high.

Aged↗