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The anti-hypertensive effect of clonidine is closely related to its central alpha-agonist action. In acute administration, the drug provokes a significant increase in the plasma concentrations of growth hormone (GH). In chronic administration, the effects of clonidine on GH secretion are not well documented. Clonidine was administered at a daily dose of 0,15 to 0,30 mg to 10 non-obese diabetic hypertensive male subjects for at least 3 months. Blood glucose and GH plasma concentrations were determined 15 times during the 24-hour cycle. Blood glucose and GH values recorded before the intake and after stopping the drug, in the basal state, after meals, after measured muscular exercise and during the first stage of sleep could be superimposed when on and off clonidine. The effects of prolonged administration of clonidine on GH secretion thus differ markedly from the effects of acute administration as in non diabetic subjects. The long-term use of clonidine does not induce a chronic increase of GH plasma concentrations which might worsen the evolution of the diabetic microangiopathy.

Since the biochemical composition of the diabetic glomerular basement membrane is still a controversial area, a study was carried out using kidneys from seven diabetic and seven nondiabetic subjects. In diabetic membranes, the glycine, hydroxylysine, glucose, galactose, and hydroxylysine-linked disaccharide unit content was increased together with a decrease in the half-cystine and sialic acid content. These findings support the view of a biochemical alteration in the human diabetic glomerular basement membrane.

HbA1c is the product of a slow, virtually irreversible reaction, occurring continuously throughout the 120 day life-span of the erythrocyte, between HbAo and glucose. It has been shown to represent the time-averaged blood glucose concentration of the preceeding 2 month period, and is independant of day to day fluctuations in the blood glucose concentration. HbA1c therefore acts as a biochemical marker and permits clinicans, by one test, to judge the quality of the diabetic control, in their patients.

A new classification based on physiopathological criteria distinguishes Type I diabetes, observed in patients with stigmata of anti-islet of Langerhans auto-immunity, from Type II diabetes without these autoimmune changes. Type I diabetes is sub-divided into Classes Ia and Ib, Class Ib comprising those cases associated with other auto-immune diseases. Serological analysis of 76 patients with clinical type Ia diabetes and 215 healthy, first degree relatives showed that the distinction between Classes Ia and Ib was not clear-cut and that patients classified clinically Ia were in fact infraclinical Ib subjects. Forty-one per cent of patients with Class Ia diabetes had anti-gastric, anti-adrenal or anti-thyroid antibodies, and 28 p. 100 of their healthy relatives also had the same types of antibodies. Several prospective studies of the families of patients with Type I diabetes have shown that anti-islet of Langerhans antibodies were associated with a high risk of diabetes. Similarly, the presence of these antibodies in patients apparently with Type II diabetes (non-insulin dependent) was associated with an increased risk of developing insulin dependence. These results illustrate the value of immunological investigations in diabetic patients. They may influence the choice of treatment in the future.

Von Willebrand factor (VIII: vWf) is a glycoprotein which is essential for normal platelet adhesion to vascular subendothelium, particularly at the high shear rates encountered in small blood vessels. VIII: vWf is distributed in plasma, platelets and subendothelium, though the contributions of each pool to normal hemostasis is unknown. Raised plasma of VIII: vWf have been frequently described in association with diabetes, the highest concentrations being found in patients with retinopathy. In addition, concentrations of VIII: vWf appear to be influenced by the degree of metabolic control of the diabetics, particularly high levels being found during diabetic coma. Plasmatic concentrations of VIII: vWf greater than normal have not been shown to result in increased platelet adhesion or aggregation, so that is seems unlikely that the high levels of plasmatic VIII: vWf contribute directly to the pathogensis of retinopathy. On the other hand, increases in VIII: vWF during episodes of poor metabolic control could be evidence of reversible injury to the vascular endothelium, whereas stable, high concentrations may indicate the presence of microangiopathy.

Six normal subjects and six normotensive insulin-dependent diabetics underwent two insulin hypoglycaemia tests after administration for three days of either a placebo or of acebutolol--a cardioselective beta-blocker--at a dose of 400 mg per day. The order in which the tests were performed was decided by random selection. Acebutolol suppressed the tachycardia which occurred as a reaction to hypoglycaemia but did not interfere with other warning symptoms and signs. In both normal subjects and diabetics, acebutolol neither worsened the initial hypoglycaemia nor did it delay a return to normal values. The increase in lactate levels following hypoglycaemia was not reduced by acebutolol but free fatty acid rebound was suppressed. Hormonal responses (glucagon, cortisol, growth hormone) were unaffected by the beta-blocker. If they are confirmed by long term studies, these results would suggest that acebutolol is safer to use than non-cardioselective beta-blockers in the treatment of coronary insufficiency and of hypertension in diabetics exposed to the risk of hypoglycaemia.

One hundred and forty five diabetics regularly attending a hospital clinic were submitted to a questionnaire assessing their knowledge of diabetes. The patients had previously been instructed in urine glucose analysis, insulin injections, diet and hypoglycaemic attacks. Despite this, they appeared to be neither better controlled nor more painstaking with their disease than before education. The replies to the questionnaire revealed that the patients had poor understanding of the symptoms and of the long-term complications of diabetes, of the criteria of good control, and of the proportion of carbohydrate in common food. Moreover, they held many fallacious ideas with regard to these concepts. The results suggest that although these diabetics had acquired sufficient knowledge to avoid the acute metabolic disturbances of diabetes and to lead a day-to-day existence with a minimum of harmful effects, they were not properly aware of the long-term consequences of diabetes and of the overall strategy for the good management of their disease. An improved educational strategy appears necessary to enable diabetics to take better care of themselves.

Among 647 patent diabetics regularly followed who attended the out-patient clinic of a hospital Diabetology Department between December 1st, 1979 and June 30th, 1980, 35% were habitual smokers, 20% ex-smokers and 45% non-smokers. Insulin-treated diabetics did not smoke more than non insulin-treated diabetics. Only one-half of the smokers declared that they had been advised by a doctor to stop smoking. This study failed to demonstrate any effect of tobacco on the prevalence or severity of diabetic retinopathy.