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Biomedical subjects

K Boyd

Publications and source records attributed to K Boyd.

At least 37 records · Page 2Linked to original sources
PubMed1992

Insulin, glibenclamide or metformin treatment for non insulin dependent diabetes: heterogenous responses of standard measures of insulin action and insulin secretion before and after differing hypoglycaemic therapy.

Using carefully selected relatively non-obese non insulin dependent diabetic patients, we were not able to show differences in standard measures of insulin production or insulin action between patients treated with a long acting crystalline zinc insulin, with glibenclamide, or with metformin for a six week period. All three drugs were hypoglycaemic, but a fall in basal hepatic glucose output measured by the 3H3 glucose technique was only seen in those patients who had an initial fasting plasma glucose above 12.0 mmol/l, irrespective of treatment.

Blood Glucose↗
PubMed1991

Influence of the 53 kDa glycoprotein on the cooperativity of the Ca(2+)-ATPase of the sarcoplasmic reticulum.

Previous results from this laboratory suggest that the 53 kDa glycoprotein (GP-53) of rabbit skeletal muscle sarcoplasmic reticulum membrane (SR) may influence coupling between Ca2+ transport and ATP hydrolysis by the Ca(2+)-ATPase. Here we report evidence that GP-53 may influence the cooperative behavior of the Ca(2+)-ATPase. The ATPase activity of the Ca(2+)-ATPase displays negative cooperative dependence (Hill coefficient n less than 1) on [MgATP] and has positive cooperative dependence (n greater than 1) on [Ca2+]free. We have determined the degree of cooperativity for native SR vesicles, SR preincubated with antiserum against GP-53 or preimmune serum, and SR partially extracted with KCl-cholate. Our results show that SR preincubated with preimmune serum or SR treated with cholate in 50 mM KCl (yielding membranes rich in GP-53) demonstrate a cooperative dependence of Ca(2+)-ATPase activity on both [ATP] and [Ca2+] similar to that of untreated SR. SR preincubated with anti-GP-53 antiserum (which causes an uncoupling of Ca2+ transport from ATP hydrolysis) or SR extracted with cholate in 1 M KCl (yielding membranes depleted of GP-53) displays decreased positive cooperative dependence on [Ca2+] and decreased negative cooperative dependence on [ATP]. The results are consistent with the interpretation that GP-53 may influence the cooperative behavior of the Ca(2+)-ATPase.

Adenosine Triphosphate↗
PubMed1991

New assessments of weight-related body image derived from extant instruments.

A study of 79 female college students examined the reliability and validity of two new size/weight-related measures of body image. The Body-size Appraisal Scale and the Overweight Preoccupation Scale were derived from existing instruments. Analyses supported the internal consistency and 2-wk. test-retest reliability of both new scales. Correlations of scores on each scale with measures of anxiety about being fat, negative body-image affect and avoidance, restrained and bulimic eating, and depression support their concurrent and construct validity. Scores on the Overweight Preoccupation Scale were also related to the extent of investment in physical appearance. Regression analyses indicated that each new scale could be predicted from several other conceptually relevant body-image attitudes, even after actual body weight was controlled.

Adolescent↗
PubMed1991

Correction of fasting hyperglycaemia with insulin or sulphonylurea lowers fasting ketone levels, but does not alter resting or post-glucose energy expenditure in non insulin dependent diabetes. Differences between the OGTT and the glucose clamp.

Sixteen non-obese non insulin dependent diabetic patients had a 75 g oral glucose tolerance test with simultaneous measurement of intermediary metabolites and of overall energy expenditure by indirect calorimetry during the test. The same patients had a 3H3 glucose infusion and hyperinsulinaemic glucose clamp procedure with glucose held at 10.0 mmol/l and insulin infused at 40 mU/m2/min. The changes in glucose and fat metabolism, in total energy balance and the fall in RQ during the glucose tolerance test did not correlate with the measures of hepatic glucose output or peripheral insulin resistance in these patients. Although the concept of insulin resistance is useful in considering the non insulin dependent diabetic state, the data derived from the body responses to a single glucose load are more relevant to the day to day fluctuation of the internal environment.

Blood Glucose↗
PubMed1990

Cataracts, intra-ocular lens implants, and a flying career.

The successful correction of cataracts by intra-ocular lens implantation (pseudophakia) restores relatively normal physiological vision to cataract victims. In 1976, Canadian Aviation Authority began to restore flight status to pilots who had developed cataracts and had such surgery. In 1987, a follow-up study was done on the first 75 relicensed pilots. No aircraft incident was related to pseudophakic vision in 16,338 h post-surgery flight time. Air Transport Rated, Senior Commercial, and Private Pilots were included in the study, which covered the whole range of flight activity and all the variations in climatic conditions that are part of Canadian aviation. We conclude that pseudophakic correction of post-surgical cataract vision does not pose any significant hazard in a flight environment.

Accident Prevention↗
PubMed1989

Poikilothermia in a 68-year-old female. A risk factor for accidental hypothermia, or hyperthermia.

A 68-year-old woman presented in wintertime in a cold climate with ataxia and numbness in her legs and was found to be profoundly hypothermic in hospital. No endocrine or neurological cause for hypothermia could be distinguished. Physiological investigation, including a sympathetic release test, exposure to gradually increasing environmental temperatures and prolonged exposure to a high temperature suggested she was at that time regulating her core temperature around a set value which was several degrees lower than normal. Metabolic rate was 42 per cent below the value predicted from standard tables. Further measurements over a one-month period in a warm climate suggested a poikilothermic temperature control mechanism, with a possible risk of environmental hyperthermia. No pathological basis for this disorder has yet been identified, but it is suggested that a small localized hypothalamic vascular event has occurred.

Aged↗
PubMed1984

The positive aspects of medical ethics today.

The author of this comment suggests that some of the important points made by Dr Adrian Rogers are vitiated by a tendency to contrast the worst of modern medical practice with an over-idealised view of the past. The state of medical ethics today, the author suggests, is more hopeful than Dr Rogers allows.

Ethical Theory↗