Effect of nateglinide on the incidence of diabetes and cardiovascular events

The ability of short-acting insulin secretagogues to reduce the risk of diabetes or cardiovascular events in people with impaired glucose tolerance is unknown.

Effects of social support on the clinical course of Crohn's disease

Social support has been found to be protective from adverse health effects of psychological stress. We hypothesized that higher social support would predict a more favorable course of Crohn's disease (CD) directly (main effect hypothesis) and via moderating other prognostic factors (buffer hypothesis).

Conformational transitions of glycine induced by vibrational excitation of the O-H stretch

Vibrational energy flow and conformational transitions following excitation of the OH stretching mode of the most stable conformer of glycine are studied by classical trajectories. "On the fly" simulations with the PM3 semiempirical electronic structure method for the potential surface are used. Initial conditions are selected to correspond to the v = 1 excitation of the OH stretch. The main findings are: (1) An an equilibrium-like ratio is established between the populations of the 3 lowest-lying conformers after about 10 picoseconds. (2) There is a high probability throughout the 150 ps of the simulations for finding the molecule in geometries far from the equilibrium structures of the lowest-energy conformers. (3) Energy from the initial excited OH (v = 1) stretch flows preferentially to 5 other vibrational modes, including the bending motion of the H atom. (4) RRK theory yields conformational transition rates that deviate substantially from the classical trajectory results. Possible implication of these results for vibrational energy flow and conformational transitions in small biological molecules are discussed.

In vivo measurement of central corneal thickness in normal chicks (Gallus gallus domesticus) with the optical low-coherence reflectometer

OBJECTIVE To determine the practicability and accuracy of central corneal thickness (CCT) measurements in living chicks utilizing a noncontact, high-speed optical low-coherence reflectometer (OLCR) mounted on a slit lamp. ANIMALS STUDIED Twelve male chicks (Gallus gallus domesticus). Procedures  Measurements of CCT were obtained in triplicate in 24 eyes of twelve 1-day-old anaesthetized chicks using OLCR. Every single measurement taken by OLCR consisted of the average result of 20 scans obtained within seconds. Additionally, corneal thickness was determined histologically after immersion fixation in Karnovsky's solution alone (20 eyes) or with a previous injection of the fixative into the anterior chamber before enucleation (4 eyes). RESULTS Central corneal thickness measurements using OLCR in 1-day-old living chicks provide a rapid and feasible examination technique. Mean CCT measured with OLCR (189.7 ± 3.34 μm) was significantly lower than histological measurements (242.1 ± 47.27 μm) in eyes with fixation in Karnovsky's solution (P = 0.0005). In eyes with additional injection of Karnovsky's fixative into the anterior chamber, mean histologically determined CCT was 195.2 ± 8.25 μm vs. 191.9 ± 8.90 μm with OLCR. A trend for a lower variance was found compared to the eyes that had only been immersion fixed. CONCLUSION Optical low-coherence reflectometry is an accurate examination technique to measure in vivo CCT in the eye of newborn chicks. The knowledge of the thickness of the chick cornea and the ability to obtain noninvasive, noncontact measurements of CCT in the living animal may be of interest for research and development of eye diseases in chick models.

Limitations of balloon sinuplasty in frontal sinus surgery

Balloon sinuplasty is a tool that is used to treat selected patients with paranasal sinus pathologies. No studies have investigated the aetiology of failed access to the frontal sinus. The aim of our study was to specify the intraoperative technical failure rate and to analyse the aetiology of the failed access to predict potential technical difficulties before surgery. We retrospectively analysed the charts of patients who underwent balloon sinuplasty from November 2007 to July 2010 at three different ENT-Centres. CT-analysis of the patients with failed access was performed. Of the 104 frontal sinuses, dilation of 12 (12%) sinuses failed. The anatomy of all failed cases revealed variations in the frontal recess (frontoethmoidal-cell, frontal-bulla-cell or agger-nasi-cell) or osteoneogenesis. In one patient, a lymphoma was overlooked during a balloon only procedure. The lymphoma was diagnosed 6 months later with a biopsy during functional endoscopic sinus surgery. In complex anatomical situations of the frontal recess, balloon sinuplasty may be challenging or impossible. In these situations, it is essential to have knowledge of classical functional endoscopic sinus surgery of the frontal recess area. The drawbacks of not including a histopathologic exam should be considered in balloon only procedures.

N-H center dot center dot center dot pi hydrogen-bonding and large-amplitude tipping vibrations in jet-cooled pyrrole-benzene

The N-H center dot center dot center dot pi hydrogen bond is an important intermolecular interaction in many biological systems. We have investigated the infrared (IR) and ultraviolet (UV) spectra of the supersonic-jet cooled complex of pyrrole with benzene and benzene-d(6) (Pyr center dot Bz, Pyr center dot Bz-d(6)). DFT-D density functional, SCS-MP2 and SCS-CC2 calculations predict a T-shaped and (almost) C(s) symmetric structure with an N-H center dot center dot center dot pi hydrogen bond to the benzene ring. The pyrrole is tipped by omega(S(0)) = +/- 13 degrees relative to the surface normal of Bz. The N center dot center dot center dot ring distance is 3.13 angstrom. In the S(1) excited state, SCS-CC2 calculations predict an increased tipping angle omega(S(1)) = +/- 21 degrees. The IR depletion spectra support the T-shaped geometry: The NH stretch is redshifted by -59 cm(-1), relative to the "free" NH stretch of pyrrole at 3531 cm(-1), indicating a moderately strong N-H center dot center dot center dot pi interaction. The interaction is weaker than in the (Pyr)(2) dimer, where the NH donor shift is -87 cm(-1) [Dauster et al., Phys. Chem. Chem. Phys., 2008, 10, 2827]. The IR C-H stretch frequencies and intensities of the Bz subunit are very similar to those of the acceptor in the (Bz)(2) dimer, confirming that Bz acts as the acceptor. While the S(1) <- S(0) electronic origin of Bz is forbidden and is not observable in the gas-phase, the UV spectrum of Pyr center dot Bz in the same region exhibits a weak 0(0)(0) band that is red-shifted by 58 cm(-1) relative to that of Bz (38 086 cm(-1)). The origin appears due to symmetry-breaking of the p-electron system of Bz by the asymmetric pyrrole NH center dot center dot center dot pi hydrogen bond. This contrasts with (Bz)(2), which does not exhibit a 0(0)(0) band. The Bz moiety in Pyr center dot Bz exhibits a 6a(0)(1) band at 0(0)(0) + 518 cm(-1) that is about 20x more intense than the origin band. The symmetry breaking by the NH center dot center dot center dot pi hydrogen bond splits the degeneracy of the v(6)(e(2g)) vibration, giving rise to 6a' and 6b' sub-bands that are spaced by similar to 6 cm(-1). Both the 0(0)(0) and 6(0)(1) bands of Pyr center dot Bz carry a progression in the low-frequency (10 cm(-1)) excited-state tipping vibration omega', in agreement with the change of the omega tipping angle predicted by SCS-MP2 and SCS-CC2 calculations.