Faculty Bibliography

An insulin-producing clone of rat insulinoma cells (RINm5F) has been used by several investigators as target cells for studies of both humoral and cell-mediated anti-islet immunity in diabetic animals and humans. We noted that the rate of proliferation of RINm5F cells obtained from different laboratories varied considerably, and, in the present study, we have compared the proliferation rates of RINm5F cells obtained from 3 laboratories (Uppsala, Sweden [UPP], Chicago [CHI] and New York [NY]). The cells were plated at 0.5 and 2.0 X 10(4)/cm2 and changes in cell number were measured over 5 days. Basal insulin release was also determined daily. In addition, binding of IgG from sera of human diabetics by each of the cell lines was also examined by a solid-phase, quantitative assay. Plating efficiency was significantly greater in the NY and CHI cells than UPP cells at both plating densities (p less than 0.025). When plated at 2 X 10(4)/cm2, the growth rate of the NY cells was faster than the others (NY: 100.1 +/- 7.8%/day, CHI: 72.2 +/- 8.1%/day, UPP: 78.3 +/- 14.0%/day, p less than 0.025). All growth rates were lower when cells were plated at 5 X 10(4)/cm2, and the differences in growth between the NY and the other cells was greater (NY: 94.1 +/- 12.2%/day, CHI: 61.8 +/- 5.8%/day, UPP: 58.1 +/- 5.6%/day). Insulin release also differed among the cells. More insulin was released by the NY cells than by the other cells on all days, and the CHI cells released more insulin than the UPP cells (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Two groups of 58 gestational diabetic women matched for age, prepregnancy weight, height, and parity were studied. The home glucose monitoring study group performed fasting and 1-hour postprandial capillary blood glucose testing after every meal. The control group was followed by conventional treatment. The incidence of macrosomia (birth weight of greater than or equal to 4000 gm) and large (greater than or equal to 90%) for gestational age infants was significantly reduced in the home glucose monitoring group. The mean birth weight of the study group was 3231 +/- 561 gm, while that of the control group was 3597 +/- 721 gm (p less than 0.002). Significantly more patients in the home glucose monitoring group were receiving insulin therapy (50% versus 21%). We believe that intensive home glucose monitoring will allow for the early identification of those gestational diabetic patients needing insulin and thus reduce the incidence of macrosomia and large for gestational age infants.

A longitudinal investigation was conducted from 1977 to 1984 on 178 families in which one or more of the children had insulin-dependent diabetes mellitus. Of 351 nondiabetic sibs followed up for an average of 54 months, ten have, thus far, become diabetic. Eight sibs were HLA identical to their diabetic proband and nine had HLA-DR3 and/or HLA-DR4. Islet cell surface antibody and islet cell cytoplasmic antibody were found from two to 74 months before the onset of clinical diabetes in 100% and 90%, respectively, of the children. A decrease in insulin secretion was observed in all of these children on entry into the study and was detected in the absence of elevated plasma glucose concentrations. The data suggest that the triad of HLA identity, pancreatic islet cell antibodies, and depressed insulin secretion identifies those sibs who are at high risk of developing insulin-dependent diabetes mellitus

Complete acquired lipoatrophic diabetes (LD) is characterized by nonketotic insulin-resistant diabetes, elevated very low-density lipoprotein (VLDL) triglyceride (TG) levels, and absent subcutaneous fat. We studied a young child in whom LD atypically developed after the onset of type 1 diabetes mellitus. On uncontrolled home diet the patient had triglyceride levels over 1,000 mg/dL on multiple occasions. In order to demonstrate the effects of caloric and dietary-fat restriction on VLDL metabolism, 3H-glycerol and autologous 125I-VLDL were used to quantitate the turnover of VLDL-TG and VLDL-apolipoprotein B (apo B) during two periods of caloric restriction. Consumption of a 900-kcal 40-g fat diet resulted in a plasma triglyceride level of 1383 mg/dL (ten-fold elevation). This hypertriglyceridemia was associated with markedly increased production rates of both VLDL-TG (73.7 mg/kg/h) and VLDL-apo B (126.9 mg/kg/d). Consumption of a 900-kcal 25-g fat diet resulted in a plasma TG level of 663 mg/dL. This reduction in plasma TG was associated with a 40% decrease in VLDL-TG production rate (PR) (45.1 mg/kg/h). There was no change in the production rate (PR) of VLDL-apo B. The hypertriglyceridemia in this patient was due to marked over production of VLDL. Furthermore, the studies demonstrate: (1) the independent benefits of caloric and dietary-fat restriction in the treatment of LD, and (2) that fat restriction lowered plasma triglyceride by its effect on the VLDL-TG production rate.

Type I hyperlipoproteinemia is a rare disorder characterized by the presence of chylomicrons in fasting plasma and dysfunction of the lipoprotein lipase system. The disease may result from primary genetic defects leading to the lack of the enzyme lipoprotein lipase or to a deficiency in the CII apoprotein activator of that enzyme. It may also appear secondary to underlying systemic diseases. We now describe a case of hyperchylomicronemia and pancreatitis with a lack of lipoprotein lipase activity as assessed by three different methods. The patient had no evidence of a plasma inactivator of lipoprotein lipase, and his plasma was able to activate the enzyme in control postheparin plasma. The postheparin plasma hepatic triglyceride lipase was normal. Tests for associated systemic diseases were negative. Six weeks after presentation, that patient's lipoprotein levels and postheparin plasma lipase activities were normal. This was a unique case of hyperchylomicronemia which for a limited time was indistinguishable from primary lipoprotein lipase deficiency by current biochemical techniques.

Cerebral edema is a sometimes fatal complication of diabetic ketoacidosis which occurs unpredictably and when biochemical parameters show improvement. A case of a young, newly diagnosed insulin-dependent diabetic boy who developed this complication while receiving a low-dose continuous insulin infusion is reported. Two hours after treatment signs of headache, ophthalmoplegia, and blurred disc margins suggested early cerebral edema. Despite fluid restriction, avoidance of alkali, and phosphate supplementation, cerebral edema ensued three hours later. This complication was then reversed by administration of mannitol. Our patient's ophthalmoplegia, unlike typical diabetic ophthalmoplegia, improved immediately and completely resolved within two weeks after this episode. It is concluded that the use of mannitol in the cerebral edema of diabetic ketoacidosis is beneficial if it is instituted promptly.