Mono- and dimethyl-1,2,4-triazolate as ligands for the mercuric ion in the cationic three-dimensional coordination polymer of [Hg-2(Mmt)(Dmt)(2)](NO3)(H2O))

Colourless crystals of [Hg-2(Mmt)(Dmt)(2)](NO3)(H2O) were obtained from a reaction of mercuric nitrate with nionomethyl- and dimethyl-1,2.4-triazolate (Mmt(-) and Dmt(-), respectively). In the crystal structure (monoclinic, C2/c (no. 15), a = 2579.4(4) b = 1231.1(2), c = 1634.8(2) pm, beta = 128.32(1)degrees V = 4073.3(11).10(6).pm(3): Z = 8, R-1 [I-0 > 2 sigma(I-0)]: 0.0355), half of the mercuric ions are essentially two-coordinate (Hg-N: 210-215 pm), the other half are tetrahedrally surrounded by N-donor atoms (Hg-N: 221, 225 pm) of the Mmt(-) and Dmt(-) anions. These three-N ligands construct a three-dimensional framework.

Imidazo[4,5-f]-1,10-phenanthrolines: Versatile ligands for the design of metallomesogens

2-Aryl-substituted imidazo[4,5-f]-1,10-phenanthrolines were used as building blocks for metal-containing liquid crystals (metallomesogens). Imidazo[4,5-f]-1,10-phenanthrolines are versatile ligands because they can form stable complexes with various d-block transition metals, including platinum(II) and rhenium(I), as well as with lanthanide(III) and uranyl ions and they can easily be structurally modified by a judicious choice of benzaldehyde precursor. None of the ligands designed for this study were liquid-crystalline. However, mesomorphism could be induced by their coordination to various metallic fragments. The thermal behavior of the metal complexes depended on the metal-to-ligand ratio and the substitution pattern of the coordinating ligands. Complexes with a metal-to-ligand ratio of 1:1 [ML, with M = Pt(II), Re(I)] were not liquid-crystal line. The lanthanide(III) complexes with a metal-to-ligand ratio of 1:2 [ML2 with M = Ln(III)] formed an enantiotropic cubic mesophase or were not liquid-crystalline, depending on the nature of the lanthanide(III) ion and the substitution pattern of the ligands. A 1:3 uranyl complex of the type [ML3](2+) exhibited a hexagonal columnar mesophase over a broad temperature range. Self-assembled monolayers of a europium(III) complex were investigated by scanning tunneling microscopy, which revealed that the complex formed well-ordered structures over long distances at the 1-octanoic acid-graphite interface. The rhenium(I) complexes and the europium(III) complexes with 2-thenoyl-trifluoroacetonate or dibenzoylmethanate and imidazo[4,5-f]-1,10-phenanthroline showed good luminescence properties.

Azaarene cis-dihydrodiol-derived 2,2 '-bipyridine ligands for asymmetric allylic oxidation and cyclopropanation

Biphenyl dioxygenase-catalysed cis-dihydroxylation of 2-chloroquinoline, 2-chloro-3-methylquinoline and 2-chloro-6-phenylpyridine substrates yielded the corresponding enantiopure cis-dihydrodiols; enantiopure 2,2'-bipyridines, synthesised in four steps from 2-chloroquinoline, proved to be efficient chiral ligands in catalytic asymmetric allylic oxidation and cyclopropanation reactions of alkenes.

Effects of antidiabetic drugs on dipeptidyl peptidase IV activity: Nateglinide is an inhibitor of DPP IV and augments the antidiabetic activity of glucagon-like peptide-1

Dipeptidyl peptidase IV (DPP IV) is the primary inactivator of glucoregulatory incretin hormones. This has lead to development of DPP IV inhibitors as a new class of agents for the treatment of type 2 diabetes. Recent reports indicate that other antidiabetic drugs, such as metformin, may also have inhibitory effects on DPP IV activity. In this investigation we show that high concentrations of several antidiabetic drug classes, namely thiazolidinediones, sulphonylureas, meglitinides and morphilinoguanides can inhibit DPP IV The strongest inhibitor nateglinide, the insulin-releasing meglitinide was effective at low therapeutically relevant concentrations as low as 25 mu mol/l. Nateglinide also prevented the degradation of glucagon-like peptide-1 (GLP-1) by DPP IV in a time and concentration-dependent manner. In vitro nateglinide and GLP-1 effects on insulin release were additive. In vivo nateglinide improved the glucose-lowering and insulin-releasing activity of GLP-1 in obese-diabetic ob/ob mice. This was accompanied by significantly enhanced circulating concentrations of active GLP-1(7-36)amide and lower levels of DPP IV activity. Nateglinide similarly benefited the glucose and insulin responses to feeding in ob/ob mice and such actions were abolished by coadministration of exendin(9-39) and (Pro(3))GIP to block incretin hormone action. These data indicate that the use of nateglinide as a prandial insulin-releasing agent may partly rely on inhibition of GLP-1 degradation as well as beta-cell K-ATP channel inhibition. (C) 2007 Elsevier B.V. All rights reserved.

Thermotropic Ruthenium(II)-Containing Metallomesogens Based on Substituted 1,10-Phenanthroline Ligands

Imidazo[4,5-f]-1,10-phenanthroline and pyrazino[2,3-f]-1,10-phenanthroline substituted with long alkyl chains are versatile ligands for the design of metallomesogens because of the ease of ligand substitution. Whereas the ligands and the corresponding rhenium(I) complexes were not liquid-crystalline, mesomorphism was observed for the corresponding ionic ruthenium(II) complexes with chloride, hexafluorophosphate, and bistriflimide counterions. The mesophases were identified as smectic A phases by high-temperature small-angle X-ray scattering (SAXS) using synchrotron radiation. The transition temperatures depend on the anion, the highest temperatures being observed for the chloride salts and the lowest for the bistriflimide salts. The ruthenium(II) complexes are examples of luminescent ionic liquid crystals.

Neuropeptides Regulate Expression of Angiogenic Growth Factors in Human Dental Pulp Fibroblasts

Abstract
INTRODUCTION:
Neuropeptides play an important role in inflammation and repair and have been implicated in mediating angiogenesis. Pulp fibroblasts express neuropeptide receptors, and the aim of this research was to investigate whether neuropeptides could regulate angiogenic growth factor expression in vitro
METHODS:
An angiogenic array was used to determine the levels of 10 angiogenic growth factors expressed by human pulp fibroblasts.
RESULTS:
Pulp fibroblasts were shown to express angiogenin, angiopoietin-2, epidermal growth factor, basic fibroblast growth factor, heparin-binding epidermal growth factor, hepatocyte growth factor, leptin, platelet-derived growth factor, placental growth factor, and vascular endothelial growth factor. Furthermore, the neuropeptides substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, and neuropeptide Y altered angiogenic growth factor expression in vitro.
CONCLUSIONS:
The regulation of angiogenic growth factor expression by neuropeptides suggests a novel role for neuropeptides in pulpal inflammation and repair.