Low-energy diets and fasting have suppressive effects on rheumatoid arthritis. It was reported recently that urine levels of pentosidine (i.e., an advanced glycation end product formed by glycosylation) is associated with the activity of rheumatoid arthritis. We conducted a regimen of caloric restriction combined with fasting in patients with rheumatoid arthritis, and then evaluated urinary pentosidine levels. Ten patients with rheumatoid arthritis underwent a 54-day caloric restriction program. Urinary pentosidine levels were measured and the Lansbury Index were determined by examining the clinical features, blood biochemistry and the inflammation activity of rheumatoid arthritis on days 0, 25 and 54. On day 0, the mean urinary pentosidine level of patients with rheumatoid arthritis was significantly higher than that of the control subjects. On day 54, the mean body weight had reduced due to caloric restriction. The mean values of the erythrocyte sedimentation rate and the Lansbury Index of patients both significantly decreased during the study. In addition, although the urinary pentosidine levels showed no significant difference between day 0 and 25, it was significantly decreased at the end of the study (day 54). The study showed that under a low energy diet a reduction of disease activity in rheumatoid arthritis was accompanied with a reduction of the urinary pentosidine.

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Abstract. By means of the euglycemic three step hyperinsulinemic clamp technique, suppression of endogenous C-peptide secretion by exogenous insulin infusion was evaluated in patients with insulinoma (n=8) and healthy controls (n=20). Euglycemic hyperinsulinemic clamp studies were performed with an artificial pancreas (STG-22 NIKKISO, Tokyo, Japan). Insulin (Actrapid human insulin) was infused at the rate of 1.12, 3, and 10 mU/kg/min.Plasma glucose levels were clamped at 80 mg/dl, and high insulin levels were maintained in all subjects (833 ± 78 µU/ml at the rate of 10 mU/kg/min insulin infusion). During the clamp studies, plasma C-peptide levels in normal subjects declined from 2.0 ± 0.2 to 0.9 ± 0.2 ng/ml, indicating suppression of endogenous insulin secretion by exogenous insulin infusion. In patients with insulinoma, plasma C-peptide levels were 3.1 ± 1.6 ng/ml in the basal state, and were not suppressed even during exogenous hyperinsulinemia.We concluded that the feedback inhibition of insulin secretion by exogenous insulin infusion is attenuated in patients with insulinoma, and that the hyperinsulinemic clamp technique may be a useful method for the diagnosis of insulinoma.