The effect of linagliptin on glycaemic control and tolerability in patients with type 2 diabetes mellitus: a systematic review and meta-analysis.

AIM: Linagliptin is a new dipeptidyl peptidase-4 inhibitor recently approved for use in the USA. The objective of this systematic review and meta-analysis was to assess effect of linagliptin on glycaemic control, biomarkers and incidence of adverse events (AEs) in patients with type 2 diabetes mellitus. METHODS: Five published and four unpublished randomized, clinical trials were identified from multiple databases. Qualitative assessments and quantitative analyses were performed. RESULTS: Nine studies included 4246 participants with 53% men, 59.4% Caucasians, 38.7% Asians, and age range 45-69 years. Linagliptin was given as monotherapy (vs. placebo) or combined with metformin (vs. metformin + placebo), sulphonylurea (vs. sulphonylurea + placebo) or pioglitazone (vs. pioglitazone + placebo). Linagliptin 5 mg/day for 12-24 weeks, significantly reduced haemoglobin A1c (HbA1c) (-0.63%, p < 0.00001), fasting plasma glucose (FPG) (-1.01 mmol/l, p < 0.00001) and improved disposition index (DI, product of insulin sensitivity and acute insulin secretion) (p = 0.0001). Linagliptin monotherapy was not more effective than metformin at reducing HbA1c or FPG. Similar proportion of patients in linagliptin and placebo groups reported AEs including upper respiratory tract infections, headaches, nausea, hypertension and back pain. CONCLUSIONS: Linagliptin was associated with modest but significant reduction in HbA1c and FPG and improved DI after 12-24 weeks. Patients who would probably benefit most are those with HbA1c <9%, already on an active agent, compliant with weight reduction strategies, and can recognize and manage hypoglycaemia, fluid retention and upper respiratory tract infections. Long-term studies are needed to determine durability of response, incidence of microvascular and macrovacular complications, cost-effectiveness and safety.

Assessment of fungal diversity using terminal restriction fragment (TRF) pattern analysis: comparison of 18S and ITS ribosomal regions.

Assessment of fungal diversity in environmental samples is currently a challenge. Several recently developed molecular methods offer new avenues for determining the presence and diversity of fungi in complex microbial communities. Terminal restriction fragment (TRF) pattern analysis was tested as a method for assessing the fungal molecular diversity of a terrestrial microbial community. Community DNA was isolated from sand samples taken from a pilot-scale petroleum-contaminated land treatment unit. PCR amplification was carried out using primers, one of which was fluorescently labeled, designed to hybridize to conserved sequences in the fungal ribosomal small subunit (18S) or the internal transcribed spacer ITS1-5.8S-ITS2 (ITS) ribosomal region. Amplicons were then digested separately with HpaII or HaeIII; fluorescently labeled TRFs were detected by capillary gel electrophoresis. ITS region TRF patterns were predicted and observed to generate a greater richness than 18S TRF patterns. Unique TRF patterns were also observed for each community examined. Finally, the ITS region showed a higher degree of specificity in matching observed TRF profiles to those generated from GenBank sequence data for species identification. These data suggest that ITS rDNA TRF pattern analysis has great potential as a rapid and specific method for fungal community analysis and species identification.

Cloning of the Aspergillus oryzae 5-aminolevulinate synthase gene and its use as a selectable marker.

The hemA gene encoding 5-aminolevulinate synthase, the first enzyme in heme biosynthesis, was cloned from Aspergillus oryzae and evaluated as a selectable marker for the transformation of filamentous fungi. Deletion of the hemA gene resulted in a lethal phenotype that could be rescued either by the supplementation of culture media with 5-aminolevulinic acid (ALA) or by transformation with the wild-type hemA gene, but not by growth on rich media, nor by the addition of exogenous heme. Transformation of a hemA deletion strain with the hemA gene linked to a lipase expression cassette yielded ALA prototrophs expressing lipase. The hemA gene can therefore be used as a selectable marker for the transformation of A. oryzae.

Rapid alkaline transfer of low molecular weight DNA from NuSieve GTG agarose gels.

The rapid alkaline transfer of high molecular weight DNA from agarose gels to nylon membranes has greatly decreased the time required for setup of Southern transfers. This technique has been used to resolve genomic DNA greater than 1000 base pairs by conventional electrophoresis on 1% agarose gels followed by alkaline transfer to nylon membrane. Now we report that this rapid alkaline method can be used for the transfer of low molecular weight DNA fragments (10 to 1000 base pairs) from NuSieve GTG agarose gels to nylon membrane.

Acute and chronic effects of barbituartes on depolarization-induced calcium influx into rat synaptosomes.

Depolarization-induced 45Ca2+ influx into synaptosomes isolated from nontreated control and acutely treated rats (given 60 mg/kg phenobarbital i.p.) was significantly depressed (54 and 37%, respectively) by an in vitro challenge with pentobarbital, 0.3 mM (final concentration). However, depolarization-induced 45Ca2+ influx into synaptosomes isolated from tolerant rats (received dietary phenobarbital, 2.5 mg/g of diet, for 13 days) was not significantly altered when the synaptosomes were challenged with 0.3 mM pentobarbital. This suggests that synaptosomal membranes adapt during chronic exposure to barbiturates to allow for an enhanced Ca2+ influx subsequent to depolarization. Our data suggest that sedation may, at least in part, occur as a result of depressed stimulus-secretion coupling and that behavioral tolerance to sedation may occur because of the development of membrane tolerance to allow enhanced calcium influx.

Acute and chronic effects of barbiturates on depolarization-induced calcium influx into synaptosomes from rat brain regions.

Male Sprague-Dawley rats (250--300 g) were randomly divided into three experimental groups: control, acute (received a single dose of 60 mg/kg of phenobarbital i.p.) and tolerant (received dietary phenobarbital, 2.5 mg/kg of milled Purina Lab Chow, for 13 days). Cerebral cortex (CT), cerebellum (CB), brain stem (BS), striatum (ST), hypothalamus (HT), and mid-brain (MB) were isolated, and the inhibitory effects of barbiturates on KCl-induced 45Ca++ influx into synaptosomes from each of these brain regions isolated from each experimental group were examined. KCl-induced 45Ca++ influx into CT, CB and BS synaptosomes from control animals was significantly depressed (39, 73 and 77% respectively) by an in vitro pentobarbital (0.3 mM) challenge. No significant depression of 45Ca++ influx was produced by pentobarbital in control synaptosomes isolated from ST, HT or MB. KCl-induced 45Ca++ influx into synaptosomes from tolerant rats was not significantly depressed by the in vitro pentobarbital challenge in any brain area. The results suggest that 45Ca++ influx into synaptosomes from CT, CB and BS is more susceptible than ST, HT and MB to inhibition by barbiturates. In addition, chronic administration of phenobarbital resulted in the adaptation of CT, CB and BS synaptosomes to the inhibitory effects of in vitro pentobarbital. This adaptation occurred in the same time frame as did the development of behavioral tolerance.