Immunologic properties of biosynthetic human insulin in vitro.

Some immunologic properties of biosynthetic human insulin (BHI) were examined in vitro. An identical behavior was found for BHI and pancreatic human insulin as standard preparation and for A14-mono-labeled BHI and pork insulin as tracer in the insulin radioimmunoassay. BHI proved to be free of human proinsulin and C-peptide. Insulin antibodies in serum of two diabetic patients showed a preferential binding of 125I-bovine insulin. However, the antibody titers were almost identical for A14-mono-labeled BHI and pork insulin. These studies did not reveal any characteristic immunologic properties of BHI compared with highly purified pancreatic human and pork insulin.

Studies on juvenile--type diabetes in children. Assessment of control under treatment with constant and variable doses of insulin with or without addition of biguanides.

Studies were carried out in juvenile-type diabetics in a home for diabetic children which offered the advantages of both "normal" living conditions and strict medical and dietetic control. In 43 insulin-dependent, juvenile diabetics, blood glucose was determined at least 3 times, and some times on 6 occasions, per 24 hours on 3 days a week over 3 months. Blood glucose was estimated in every case of suspected insulin reaction. Determination of cholesterol, triglyceride, growth hormone and antibodies against bovine and porcine insulin were also carried out. Randomized groups of patients were treated alternately with 1) constant, 2) variable insulin doses, 3) addition of biguanides (metformin). Calculated parameters included mean daily blood glucose, mean of absolute differences between daily blood glucose values, daily insulin requirements, frequency of verified insulin reactions and mean blood glucose profiles pre- and postprandially. Addition of biguanides did not decrease blood glucose differences nor the frequency of hypoglycemic episodes. Daily insulin doses were lowered by the drug. Variable insulin doses appeared to be superior to constant ones. Daily insulin requirements were positively correlated with age and weight of patients. Elevated levels of cholesterol were lowered by biguanides. In suspected cases of insulin reaction, blood glucose levels above 100 mg/100 ml were found in more than 40%. No differences existed in insulin requirements, age and duration of diabetes between childhood diabetics with or without significant titers of insulin antibodies. Three postprandial blood glucose determinations gave no essential information over and above the 3 preprandial estimations as far as blood glucose fluctuations were concerned. No smoothing effect of biguanides was apparent from the study whereas an insulin-sparing effect is exerted by these drugs as well as a lowering of elevated levels of cholesterol.