Efficacy and safety of sitagliptin when added to insulin therapy in patients with type 2 diabetes.

OBJECTIVE: To evaluate the efficacy and tolerability of sitagliptin when added to insulin therapy alone or in combination with metformin in patients with type 2 diabetes. METHODS: After a 2 week placebo run-in period, eligible patients inadequately controlled on long-acting, intermediate-acting or premixed insulin (HbA1c > or = 7.5% and < or = 11%), were randomised 1:1 to the addition of once-daily sitagliptin 100 mg or matching placebo over a 24-week study period. The study capped the proportion of randomised patients on insulin plus metformin at 75%. Further, the study capped the proportion of randomised patients on premixed insulin at 25%. The metformin dose and the insulin dose were to remain stable throughout the study. The primary endpoint was HbA1c change from baseline at week 24. RESULTS: Mean baseline characteristics were similar between the sitagliptin (n = 322) and placebo (n = 319) groups, including HbA1c (8.7 vs. 8.6%), diabetes duration (13 vs. 12 years), body mass index (31.4 vs. 31.4 kg/m(2)), and total daily insulin dose (51 vs. 52 IU), respectively. At 24 weeks, the addition of sitagliptin significantly (p < 0.001) reduced HbA1c by 0.6% compared with placebo (0.0%). A greater proportion of patients achieved an HbA1c level < 7% while randomised to sitagliptin as compared with placebo (13 vs. 5% respectively; p < 0.001). Similar HbA1c reductions were observed in the patient strata defined by insulin type (long-acting and intermediate-acting insulins or premixed insulins) and by baseline metformin treatment. The addition of sitagliptin significantly (p < 0.001) reduced fasting plasma glucose by 15.0 mg/dl (0.8 mmol/l) and 2-h postmeal glucose by 36.1 mg/dl (2.0 mmol/l) relative to placebo. A higher incidence of adverse experiences was reported with sitagliptin (52%) compared with placebo (43%), due mainly to the increased incidence of hypoglycaemia (sitagliptin, 16% vs. placebo, 8%). The number of hypoglycaemic events meeting the protocol-specified criteria for severity was low with sitagliptin (n = 2) and placebo (n = 1). No significant change from baseline in body weight was observed in either group. CONCLUSION: In this 24-week study, the addition of sitagliptin to ongoing, stable-dose insulin therapy with or without concomitant metformin improved glycaemic control and was generally well tolerated in patients with type 2 diabetes.

Structure and mapping of the human thymopoietin (TMPO) gene and relationship of human TMPO beta to rat lamin-associated polypeptide 2.

Thymopoietins (TMPOs, previously abbreviated TPs) alpha (75 kDa), beta (51 kDa), and gamma (39 kDa) are related nuclear proteins expressed in many or all tissues. TMPO alpha is present diffusely throughout the nucleus, while TMPOs beta and gamma are localized to the nuclear membrane. Here we report the cloning and analysis of a single TMPO gene encoding TMPOs alpha, beta, and gamma, which are produced by alternative mRNA splicing, as previously inferred from cDNA sequences. The eight exons of the TMPO gene are spread over approximately 35 kb. Exon 4, which is spliced into TMPO alpha mRNA, contains sequences that encode a putative basic nuclear localization motif. Exon 8, which is spliced into TMPO beta and gamma mRNAs, encodes a hydrophobic putative membrane-spanning domain that is thought to target TMPOs beta and gamma to the nuclear membrane. TMPO beta appears to be the human homologue of the recently described rat protein LAP2 (lamina-associated polypeptide 2), which is thought to play an important role in the regulation of nuclear architecture by binding lamin B1 and chromosomes in a manner regulated by phosphorylation during mitosis (K. Furukawa and L. Gerace, La Jolla, pers. comm., 22 Nov. 1994). The human TMPO gene maps to chromosome band 12q22.

Three distinct human thymopoietins are derived from alternatively spliced mRNAs.

Thymopoietin (TP) was originally isolated as a 5-kDa 49-aa protein from bovine thymus in studies of the effects of thymic extracts on neuromuscular transmission and was subsequently observed to affect T-cell differentiation and function. We now report the isolation of cDNA clones for three alternatively spliced mRNAs that encode three distinct human T-cell TPs. Proteins encoded by these mRNAs, which we have named TP alpha (75 kDa), TP beta (51 kDa), and TP gamma (39 kDa), contain identical N-terminal regions, including sequences nearly identical to that of the originally isolated 49-aa protein, but divergent C-terminal regions. TP mRNAs are expressed in many tissues, most abundantly in adult thymus and fetal liver of the tissues so far examined. Distinct structural domains and functional motifs in TPs alpha, beta, and gamma suggest that the proteins have unique functions and may be directed to distinct subcellular compartments.

Nucleic acid hybridization in plasma: method for the quantitation of poly(I).poly(C12, U) in plasma of cancer patients.

Using a new method for the direct measurement of the double-stranded RNA (dsRNA) molecule poly(I).poly(C12, U) in plasma, levels of 100 X 10(-9) g of drug were routinely quantified. The samples were digested by proteinase K in a buffered solution containing 0.1% of Brij-35 and deoxycholate detergents. The digestions were terminated after 1 h by the addition of Brij-58 and boiling saturated NaI (1.67 g/ml). Serially diluted samples were filtered onto nitrocellulose and the filters washed and hybridized. Levels of the hybridized-radioactive probe, synthesized de novo in an RNA dependent DNA transcription system, were determined by liquid scintillation spectrophotometry and quantified by comparison to a standard curve. The efficiency of hybridization declined when the plasma concentration in the reaction fell below 1.0 mg/ml. Incubation and denaturation temperatures significantly altered the amount of radioactive probe hybridized; results varied in the extent of hybridization and in the concentration range of dsRNA showing a linear response. Elevated temperature during proteinase K digestion showed reduced hybridization efficiencies: 100% at 25, 80% at 37, 35% at 45, and 25% at 55 degrees C. Incubation at elevated temperatures, prior to the addition of NaI, caused a decline in the amount of radioactivity hybridized, but did not have an effect during hybridization.