Biomedical subjects
Publications and source records attributed to R M Pearson.
Measurements of the back central optical radius in the course of 336 hours of hydration of lathe cut corneal lenses disclosed changes in curvature which were more rapid and of greater magnitude than those previously reported for poly (methyl methacrylate) lenses.
The effect of 40 mg oxprenolol on stage-fright was assessed in 24 musicians in a double-blind crossover trial. Musical performance judged by two professional assessors was found to improve. Greatest improvement was seen on the first performance and in those most affected by nervousness.
Hard contact lenses of identical specification, but manufactured from different materials, were immersed in water for up to 168 hours. The back central optic radius of each lens was periodically measured. The magnitude and time course of curvature change during hydration were found to vary with the material.
There is increased concern over the apparent rise in incidence of patients with carcinoma of the ovary, particularly in older women. In an attempt to identify aetiological factors 300 women with cancer of the ovary diagnosed at laparatomy were studied. A questionnaire was administered to these women (Group A) and to two control groups matched by age. The first control group (Group B) comprised patients in a gynaecological ward and the second (Group C) comprised were shown in the obstetric history of the three groups. Fewer of the women in Group A had married and fewer had ever been pregnant and the family size was smaller. Significantly fewer of them recollected an attack of mumps, measles, or rubella. In all, only 81 of the whole series of 900 had used oral contraceptives, 19 of Group A and 31 in each of the control groups, a statistically significant deficiency. These findings support those of other investigations and suggest lines of further inquiry.
Thirteen hypertensive patients entered a double-blind crossover trial of guanethidine and oxprenolol in combination. In nine patients who completed the trial there was an additive effect on blood pressure, but the combination had a smaller effect on heart rate than was expected from the individual effects, and side effects were not increased. During treatment with oxprenolol the plasma potassium concentration rose from 3.6 mmol (mEq)/1 to 3.9 mmol (mEq)/1. No correlation was found between the plasma oxprenolol concentration and changes in blood pressure or response to injected isoprenaline, but measurements of plasma oxprenolol concentrations were of value in determining compliance with the protocol.
1 The effect of rapid (10s) injections of diazoxide was studied in ten hypertensive patients with varying degrees of impairment of renal function. 2 There was a significant correlation between the patient's plasma urea concentration and reduction in mean arterial blood pressure. Diazoxide was also shown to be less highly protein bound in patients with renal failure. 3 It is suggested that the explanation for the increased hypotensive effect of diazoxide observed in patients with reduced renal function is related to higher unbound drug concentrations.
1 The effect of intravenous injections of labetalol at doses of 1 and 2 mg/kg was studied in 15 patients with severe hypertension inadequately controlled by beta-adrenoreceptor-blocking drugs. 2 At a dose of 1 mg/kg there was a slight but statistically insignificant reduction in blood pressure. When 2 mg/kg was given there was a prolonged (6 h) significant reduction in lying blood pressure. At both dose levels there was a small initial increase in pulse rate but forced peak flow was not affected. 3 Side-effects were limited to transient postural hypotension and a feeling of warmth. 4 It is concluded that intravenous labetalol at a dose of 2 mg/kg is safe and effective in rapidly reducing blood pressure in patients already receiving beta-adrenoreceptor-blocking drugs.
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In celebration of the centenary of August Müller's pioneering work on contact lenses, we present, for the first time, a full translation into English of Part III of his inaugural dissertation. Müller describes his attempts to correct his own -14.00 diopters of myopia with "cornea-lenses," which were essentially glass scleral lenses. His inability to tolerate lens wear for more than half an hour was probably due to a) limbal pressure as a result of the primary optic diameter being too small, and b) the use of water to occupy the space between the lens and cornea, which would have induced severe corneal edema. Many of the observations and recommendations embodied in Müller's thesis, such as the importance of a good fit, adequate tear flow and rounded edges, are still relevant to contact lens practice today.
A double blind controlled trial of ornithine alpha-ketoglutarate (OAKG) was carried out on 50 patients admitted to the Royal Free and Royal Northern Hospitals, London, suffering from a recent stroke. Significant improvement was found in patients treated with OAKG when examined on the fifth day of therapy as compared to their control cases. The therapy was given for 5 days. When the patients in the treated and the control groups were compared 10 days after the beginning of treatment, there were no differences between the 2 groups. Implications of these findings are discussed.
Hypoxia is well known to cause an increase in brain anaerobic glycolysis. Ornithine alpha ketoglutarate (OAKG) given to six dogs was shown to attenuate these metabolic disturbances caused by hypoxia. Brain oxygen utilization was higher after ornithine alpha ketoglutarate during hypoxia than during a period of hypoxia alone. It is suggested that the clinical usefulness of OAKG should be explored in those situations where there is cerebral hypoxia or ischemia.