Telomeres are specialized protein-DNA complexes that compose the ends of eukaryotic chromosomes. Telomeres protect chromosome termini from degradation and recombination and act together with telomerase to ensure complete genome replication. We have determined the crystal structure of the two-subunit Oxytricha nova telomere end binding protein (OnTEBP) complexed with single strand telomeric DNA at 2.8 A resolution. The structure reveals four oligonucleotide/oligosaccharide-binding folds, three of which form a deep cleft that binds the ssDNA, and a fourth that forms an unusual protein-protein interaction between the alpha and beta subunits. This structure provides a molecular description of how the two subunits of OnTEBP recognize and bind ssDNA to form a sequence-specific, telomeric nucleoprotein complex that caps the very 3' ends of chromosomes.

OBJECTIVE -To assess the effect of mealtime amylin replacement with pramlintide on long-term glycemic and weight control in patients with type 1 diabetes. RESEARCH DESIGN AND METHODS-In a 52-week, double-blind, placebocontrolled, multicenter study, 480 patients with type 1 diabetes were randomized to receive preprandial injections of placebo or 30 g pramlintide q.i.d., in addition to existing insulin regimens. At week 20, pramlintide-treated patients were re-randomized to 30 or 60 g pramlintide q.i.d. if decreases from baseline in HbA 1c were Ͻ1% at week 13. Of the 342 patients who completed the 52-week study, 236 individuals (ϳ70%) elected to participate in a 1-year openlabel extension in which all patients received 30 or 60 g pramlintide q.i.d..RESULTS -Treatment with pramlintide led to a mean reduction in HbA 1c of 0.67% from baseline to week 13 that was significantly (P Ͻ 0.0001) greater than the placebo reduction (0.16%), and a significant placebo-corrected treatment difference was sustained through week 52 (P ϭ 0.0071). The greater HbA 1c reduction was associated with an average weight loss, rather than weight gain, and was not accompanied by an increased overall event rate of severe hypoglycemia. In the open-label extension, mean HbA 1c levels decreased rapidly in patients receiving pramlintide for the first time and remained at reduced levels in patients who continued pramlintide treatment. The most common adverse events reported by the pramlintide group were mild nausea and anorexia, which both occurred during the initial weeks of treatment and dissipated over time.CONCLUSIONS -Mealtime pramlintide treatment as an adjunct to insulin improved longterm glycemic control without inducing weight gain or increasing the overall risk of severe hypoglycemia in patients with type 1 diabetes. Diabetes Care 25:724 -730, 2002

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The objective of this study was to assess the effect of mealtime amylin replacement with pramlintide on long-term glycemic and weight control in subjects with type 2 diabetes. This 52-week, randomized, placebo-controlled, multicenter, double-blind, dose-ranging study in 538 insulin-treated subjects with type 2 diabetes compared the efficacy and safety of 30-, 75-, or 150-microg doses of pramlintide, a synthetic analogue of the beta-cell hormone amylin, to placebo when injected subcutaneously three times daily (TID) with major meals. Pramlintide therapy led to a mean reduction in HbA1c of 0.9% and 1.0% from baseline to week 13 in the 75- and 150-microg dose groups, which was significant compared to placebo (p = 0.0004 and p = 0.0002, respectively). In the 150-microg dose group, there was a mean reduction in HbA1c of 0.6% from baseline to week 52 (p = 0.0068 compared to placebo). The greater reduction in HbA1c with pramlintide was achieved without increases in insulin use or severe hypoglycemia, and was accompanied by a significant (p < 0.05) reduction in body weight in all dose groups compared to placebo. Three times the proportion of subjects in the 150-microg pramlintide group compared to the placebo group achieved a concomitant reduction in both HbA1c and body weight from baseline to week 52 (48% versus 16%). The most common adverse event reported with pramlintide treatment was nausea, which was mild to moderate and dissipated early in treatment. The results from this study support the safety and efficacy of pramlintide administered three times a day with major meals, in conjunction with insulin therapy, for improving long-term glycemic and weight control in subjects with type 2 diabetes.

OBJECTIVE -To assess the postprandial glucose-lowering effect of the human amylin analog pramlintide when given with either regular insulin or insulin lispro in subjects with type 1 diabetes, with an emphasis on the optimal dose timing relative to meals.RESEARCH DESIGN AND METHODS -In this randomized, single-blind, placebocontrolled, five-way crossover study, 19 subjects with type 1 diabetes using regular insulin and 21 subjects with type 1 diabetes using insulin lispro underwent five consecutive mixed meal tests. In randomized order, subjects received subcutaneous injections of placebo at Ϫ15 min or 60 g pramlintide at Ϫ15, 0, ϩ15, or ϩ30 min relative to the meal after an overnight fast. Regular insulin or insulin lispro was injected at Ϫ30 and 0 min, respectively, at doses that were adjusted appropriately for both the content of the standardized meal and the anticipated effects of pramlintide. Plasma glucose concentrations were measured before and during the 4-h postmeal period.RESULTS -In both the regular insulin and insulin lispro groups, pramlintide injections at all four time points lowered the postprandial glucose excursion (36 to Ͼ100% reduction in incremental area under the concentration time curve from 0 to 4 h (AUC 0 -4 h ) compared with placebo. However, only preprandial injections of pramlintide (Ϫ15 and 0 min) were able to prevent the initial postprandial surge in glucose. The optimal time for pramlintide injection was 0 min, which reduced the postprandial glucose excursion by Ͼ100% compared with regular insulin plus placebo (incremental AUC 0 -4 h : Ϫ0.6 Ϯ 2.5 vs. 11.0 Ϯ 2.9 mmol ⅐ h Ϫ1 ⅐ l Ϫ1 , P Ͻ 0.0007) and by 75% compared with insulin lispro plus placebo (incremental AUC 0 -4 h : 2.5 Ϯ 2.1 vs. 10.0 Ϯ 2.5 mmol ⅐ h Ϫ1 ⅐ l Ϫ1 , P Ͻ 0.0098). No serious adverse events were reported.CONCLUSIONS -Pramlintide, given at or just before a meal, reduces the postprandial glucose excursion in subjects with type 1 diabetes, regardless of whether added to regular insulin or a rapid-acting insulin analog.