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Biomedical subjects

D Pyke

Publications and source records attributed to D Pyke.

17 recordsLinked to original sources
PubMed1998

Evidence that the age at diagnosis of IDDM is genetically determined.

OBJECTIVE: The aim of this study was to determine the impact of genetic or environmental factors on the age or time of onset of IDDM by studying pairs of twins and siblings concordant for the disease. RESEARCH DESIGN AND METHODS: From 404 twin pairs referred to a diabetic twin study, we selected pairs concordant for IDDM: 1) 116 identical pairs with an index twin diagnosed diabetic under age 60 years and 2) 12 identical and 12 nonidentical matched twin pairs. From 972 families referred to a population-based diabetic family study, we selected sibling pairs with IDDM: 33 pairs with an index case diagnosed diabetic under age 21 years. Twin and sibling pairs were analyzed for intraclass correlations for age and time of diagnosis. RESULTS: Of twins concordant for IDDM, the age at diagnosis correlated 1) in 116 identical pairs (R = 0.94; P < 0.000001) and 2) more closely in 12 identical twins (R = 0.96, P < 0.000001) than 12 nonidentical twins (R = 0.59, P = 0.046). Of 33 sibling pairs with IDDM, the age, but not the time, of diagnosis was correlated (R = 0.53, P = 0.0016). CONCLUSIONS: Correlations within pairs of twins and siblings for age, not time, at diagnosis suggest that much of the variability of the age at diagnosis of IDDM is genetically determined.

Adolescent↗
PubMed1985

Hyperglycaemia: imitating Claude Bernard's piqûre with drugs.

Hyperglycaemia lasting for hours, has been produced in unanesthetized cats, rabbits and rats by injection into the cerebral ventricles or the cisterna magna of a variety of drugs (morphine, etorphine, pethidine, beta-endorphin, enkephalin, bombesin, TRH, cholecystokinin, naloxone, propranolol, phentolamine, chloralose, magnesium chloride and GABA). These drugs probably act at the ventral surface of the brainstem and initiate a sympathetic discharge to the adrenals which results in a prolonged release of relatively small amounts of adrenaline. When adrenaline is released in this way hyperglycaemia may be the only effect. The mechanism of the piqûre hyperglycaemia of Claude Bernard may be the same, although Bernard assumed that it resulted from an effect on the floor of the fourth ventricle, i.e. on the dorsal surface of the brainstem. However, it is clear from his description that his trochar not only pricked the floor of the fourth ventricle but penetrated to the ventral surface of the brainstem. Release of adrenaline from the adrenals is usually regarded as a stress response, as in fight, flight, fear or rage when it is suddenly released in large amounts and produces its typical cardiovascular and ocular reactions. The results now obtained with drugs injected intraventricularly or intracisternally suggest an additional physiological role for adrenaline when it is released over prolonged periods and in relatively small amounts producing only hyperglycaemia. Such a release may play a role in the day-to-day control of blood glucose, and its disturbance might underlie non-insulin-dependent diabetes.

Adrenergic beta-Antagonists↗
PubMed1980

Genetic patterns in diabetes mellitus.

Diabetes comprises many syndromes whose only common feature is a high blood glucose level. Some are entirely genetic, some partially so, and others not at all. Perhaps the most important advance in the past 10 years is proof that insulin dependent diabetes is genetically different from the insulin independent form. Most progress has been made in unraveling the etiology of insulin dependent diabetes, although more information is needed before the mode of inheritance is finally settled. The last few years have produced a plethora of new facts about insulin dependent diabetes mellitus, providing geneticists, clinicians, and epidemiologists with the fascinating challenge of a disease with an apparently genetic susceptibility to external (environmental) triggers. Little progress has been made in the field of insulin independent diabetes, and one might safely predict that the diabetic syndrome will still produce some nightmares for researchers who take up the challenge of trying to unravel its various etiologies and methods of inheritance.

Adolescent↗
PubMed1973

Diabetic pregnancy.

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Abortion, Therapeutic↗