Impaired glucose tolerance in pancreas grafted diabetic patients is due to insulin secretory defects.

INTRODUCTION: Pancreas transplantation in diabetic patients can sustain insulin independence for years. The aim of the study was to measure the incidence of an impaired or diabetic glucose tolerance in patients after successful transplantation and analyse insulin resistance and insulin secretion. METHODS: 174 Type 1 diabetic recipients of simultaneous pancreas/kidney (SPK) transplants were investigated early (three months) and 95 patients late (five years) after transplantation using an oral glucose tolerance test combined with an iv arginine load. RESULTS: Although mean fasting blood glucose and HbA1c levels were within the normal range, only 65% of the patients displayed a normal glucose tolerance (NGT), whereas 25% had an impaired (IGT) and 10% showed a diabetic glucose tolerance (DGT). Fasting blood glucose and HbA1c values were significantly lower in patients with NGT compared to graft recipients with IGT or DGT, either three months or five years after SPK. Indicators of insulin resistance (fasting insulin, HOMA-IR, Matsuda/de Fronzo Index) were elevated in all graft recipients, but no differences were found between groups. In contrast insulin secretion was significantly reduced in patients with IGT and DGT early and late after transplantation. SUMMARY: Insulin resistance is a common feature after pancreas transplantation. However, either three months or five years after SPK abnormal glucose tolerance was mainly due to a reduced glucose- and arginine-induced secretory response of insulin.

Inhibition of wild-type human immunodeficiency virus and reverse transcriptase inhibitor-resistant variants by Phyllanthus amarus.

Substantial progress has been made in research on natural products which effectively inhibit HIV-1 replication. Many active compounds were isolated from traditionally used medicinal plants including Phyllanthus species. This study shows that aqueous as well as alcohol-based Phyllanthus amarus extracts potently inhibit HIV-1 replication in HeLa CD4(+) cells with 50% effective concentration (EC(50)) values ranging from 0.9 to 7.6 microg/ml. A gallotannin enriched fraction showed enhanced activity (0.4 microg/ml), and the purified gallotannins geraniin and corilagin were most active (0.24 microg/ml). HIV-1 replication was also blocked in CD4(+) lymphoid cells with comparable EC(50) values. Applying a cell-based internalization assay, we could demonstrate 70-75% inhibition of virus uptake at concentrations of 2.5 microg/ml for the water/alcohol extract and geraniin. In addition, a concentration-dependent inhibition of HIV-1 reverse transcriptase (RT) could be demonstrated in vitro. The 50% inhibitory concentration (IC(50)) values varied from 1.8 to 14.6 microg/ml. The ability to inhibit replication of a variety of RT inhibitor-resistant HIV-1 strains points to the potential of P. amarus extracts, as natural products, in the chemotherapy of HIV infections.