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Biomedical subjects

C Davison

Publications and source records attributed to C Davison.

At least 37 records · Page 2Linked to original sources
PubMed1990

Post keratoplasty dimensional and refractive change in contact lens and spectacle corrected cases.

Two groups of patients who had corneal transplantations for keratoconus were analysed retrospectively. One group had been visually corrected with corneal contact lenses and the second group had worn spectacles or used no optical correction. The reduction in post graft corneal astigmatism with time following removal of sutures was examined by the method of regression in groups. The results showed that the reduction in corneal astigmatism was significantly greater in the contact lens wearing group.

Astigmatism↗
PubMed1985

Pituitary function following megavoltage therapy for Cushing's disease: long term follow up.

Eight patients who had received megavoltage therapy for Cushing's disease 5-12 years previously have been reviewed. The long term response to this therapy was assessed with respect to efficacy of treatment in inducing continued remission and disturbance of hypothalamic-pituitary function. One patient showed clear evidence of relapse of Cushing's disease. One patient had unequivocal hypopituitarism. Basal levels of growth hormone (GH), TSH, LH, and FSH were not statistically different from controls, but provocative testing revealed significant abnormalities of response of cortisol/ACTH, GH, prolactin and LH. Six out of eight patients had absent diurnal cortisol variation and five patients had elevated serum prolactin levels. Thus, in this group of patients normal pituitary-adrenal function has not been satisfactorily restored. It is clear that significant disturbances of hypothalamic-pituitary function follow mega-voltage therapy and these may progress to overt hypopituitarism.

Adult↗
PubMed1977

Comparative metabolism of benorylate and an equivalent mixture of aspirin and paracetamol in neonate and adult rabbits.

1. Benorylate was well absorbed in rabbits, but more slowly than an equimolar mixture of aspirin and paracetamol. 2. Benorylate was extensively hydrolysed and converted to the typical metabolites of aspirin and paracetamol by both neonate and mature rabbits. 3. Absorption of either aspirin-paracetamol or benorylate was slower in neonate rabbits than in adult rabbits. 4. The excretion rate in adult rabbits was faster, for both aspirin and paracetamol metabolites, than in neonate rabbits.

Acetaminophen↗
PubMed1977

Species differences in the metabolism of hycanthone.

The rate of excretion of labelled hycanthone has been determined in bile and urine from three strains of rats (Sprague-Dawley, hooded and Gunn), and from dogs, cats, rabbits and monkeys. Bile was the major route of excretion in all species; the half-life for excretion of total radioactivity ranged from 1.6 to 3.0 hours. Relatively little of the radioactivity was found in the urine, except in the monkey and notably in the cat. Most of the radioactivity in the bile and urine was found in conjugated form, or as polar metabolites; cat urine, however contained a high percentage of hycanthone and less polar metabolites. Some fifteen metabolites have been seen in bile, and/or urine, and nine from in vitro incubations with microsomal preparations. Five of these, including hycanthone, have been chemically characterized, and two others tentatively identified.

Animals↗
PubMed1977

A gas chromatography-mass fragmentographic method for the assay of ajmaline and its monochloroacetyl ester.

A gas chromatograph-mass fragmentography method for simultaneous assay of 17-monochloroacetyl-ajmaline (MCAA) and its hydrolysis product, ajmaline, is described. Recovery of both compounds from whole blood averaged 71%. About 5% of MCAA was hydrolyzed during the assay procedure. The method was accurate and precise to within a few percent. It was suitable for assays of blood levels in the dog after an i.v. dose of 2 mg/kg or an oral dose of 5 mg/kg.

Administration, Oral↗
PubMed1976

Alcohol-induced taste aversion in golden hamsters.

Multiple injections of alcohol were effective in producing substantial aversions to saccharin-flavored water in golden hamsters. A dose of 1.76 g of alcohol per kg produced a long-lasting aversion, whereas aversion produced by injections of 1.17 g per kg extinguished rapidly.

Animals↗
PubMed1976

Hyperinsulinemia: effects on body weight, obesity and motivated behaviors.

Five experiments were performed to evaluate the physiological and behavioral similarities between lesions of the ventromedial hypothalamus (VMH) and injection-produced hyperinsulinemia. It was found that the rate of weight gain and fat deposition in both adult and weanling rats was essentially the same for both VMH and hyperinsulinemic rats. Measures of activity and taste preference measures yielded no differences between hyperinsulinemic rats and intact rats. Electric shock thresholds revealed a decrease in reactivity for hyperinsulinemic rats compared to intact rats. A hypothesis was suggested in which a combination of hypophysectomy, gonadectomy, and hyperinsulinemia might produce most of the physiological effects seen with VMH lesions. It was also suggested that since these physiological alterations radically modify the organism's internal environment, the behavioral effects of VMH lesions may be the results of the attempts of a brain-damaged animal to maintain new physiological conditions.

Adipose Tissue↗
PubMed1976

The absorption, distribution and metabolic fate of danazol in rats, monkeys and human volunteers.

The metabolism of danazol has been investigated in the rat, the monkey and in human volunteers using 14C-isoxazolo-, 14C-ethynyl, 6,7-tritiated and unlabelled compound. The drug was well absorbed, and rapidly metabolized; approximately 60 endproducts were seen in monkey urine. Four compounds have been unequivocally identified in monkey fecal extracts by physico-chemical methods; several others have been tentatively identified by chromatographic means. Very little unchanged danazol was found in monkey urine or feces at physiological dosages; the major identified urinary and fecal end-products were 2-hydroxymethylethisterone, delta1-2-hydroxymethylethisterone and ethisterone. In the rat the major portion of the radioactivity was excreted in the fecal matter, while in the monkey about equal portions were eliminated in urine and feces. Tissue distribution studies in monkeys and rats showed concentrations greater than the plasma levels only in the liver, adrenal glands and kidneys.

Animals↗
PubMed1975

Nitrogen exchange across the lungs in resting man.

The relationship between the partial pressure of N2 in the inspired air (PIN2), and the nitrogen transfer across the lungs (VN2), has been examined in 8 resting subjects, and a study made of the effect of diet upon this relationship. Alterations in PIN2, over the range 60 mm Hg below, to 20 mm Hg above ambient PIN2, caused changes in VN2 which could be described by a linear equation. These changes agreed both in magnitude and direction with those predicted by a four-compartment electrical analogue of the body N2 stores. They were not affected by the protein content of a meal taken 3/4 hr before the start of measurements of VN2. The study has shown that any imbalance in N2 transfer across the lungs is very small and that the open-circuit method of measuring O2 consumption is valid.

Adult↗