Hemochromatosis heterozygotes may be predisposed to end-stage liver disease from other causes. The aims of this study were to determine the prevalence of the hemochromatosis mutation, C282Y, in end-stage liver disease and to determine if transplantation of C282Y heterozygous livers adversely affected survival. The C282Y status of patients who underwent hepatic transplantation and, whenever possible, their donors, was determined and correlated with hepatic iron status. Survival was compared in patients who received livers from heterozygotes and normals. Prevalence of C282Y in recipients was compared with 5,211 voluntary blood donors. Twenty-six C282Y heterozygotes were detected among 304 transplant recipients (8.6%) compared with a prevalence of 8.4% in blood donors. Six of 26 heterozygous recipients (23%) had >/=2+ iron staining in their explanted livers compared with 40 of 277 wild-type livers (14%) (P = ns). There was no significant difference in mean hepatic iron concentration between C282Y heterozygotes and wild-type explanted livers with >/=2+ iron staining. Seven of 31 patients (23%) with alcoholic liver disease were C282Y heterozygotes. Twenty-four heterozygotes were detected in 141 donors (17.0%). Survival did not differ between recipients who received heterozygous or normal livers. The prevalence of C282Y heterozygotes in patients requiring liver transplantation does not differ significantly from the general population. Heterozygotes are not at increased risk of developing end-stage liver disease. Transplantation of C282Y heterozygous livers is a safe, effective practice.

Cam-2445 is a selective, high-affinity NK1 receptor antagonist that is a potentially useful treatment for arthritis, asthma, migraine, anxiety, psychosis, and emesis. Cam-2445 exhibits low aqueous solubility and high lipophilicity and has a molecular weight of 470. Cam-2445 has poor oral bioavailability and the purpose of this research was to examine the potential barriers to the oral bioavailability of Cam-2445. Cam-2445 was relatively stable at 37 degrees C in 0.1 N HCl, 5 microM alpha-chymotrypsin, rat intestinal perfusate, and in rat jejunal brush border membrane suspension. High permeability was observed from CACO-2 cells and from rat single-pass intestinal perfusions. Cam-2445 was administered as a solution to rats by intravenous (i.v.), oral (p.o.), intraduodenal (i.d.), and intraportal (i.p.v.) routes. The total oral bioavailability was poor at 1.4%. Absorption appeared to be rapid after i.d. dosing; bioavailability was 26%, and 54% of the dose was absorbed intact into the portal system. After i.p.v. dosing, 48% of the dose was available to the systemic circulation. The elimination t1/2 after i.d. dosing (2.91 h) was comparable to that i.v. dosing (2.93 h), whereas it was significantly longer after p.o. dosing (12.4 h). The p.o. dose apparently precipitated in the gastrointestinal (GI) tract, resulting in low oral bioavailability. These results indicated that neither stability in the GI tract nor membrane transport were major obstacles to the absorption of Cam-2445. While hepatic extraction of 52% was significant, the low aqueous solubility of Cam-2445, as well as the differences noted between p.o. and i.d. studies, strongly support GI dissolution and/or precipitation as the limiting factor for the oral bioavailability of the compound.

In this paper we describe the development of a novel series of non-peptide neuromedin-B (NMB) receptor ligands as exemplified by PD 165929. PD 165929, which exhibits nanomolar affinity for the NMB receptor (Ki=6.3nM), has been demonstrated to be a competitive antagonist at this receptor (appKB=7.6nM) and is selective over the corresponding gastrin-releasing peptide (GRP) receptor type (Ki>10000nM).

The design and synthesis of conformationally constrained, nonpeptide templates (1,1,6-trisubstituted indanes) which allow the incorporation of two adjacent amino acid side chains, plus a third binding group in an orientation similar to that found in alpha-helices are reported. Six racemic and two homochiral Phe-Phe and Trp-Phe mimetics were synthesised and evaluated in tachykinin receptor binding assays as molecular probes for the binding conformation of the endogenous peptides. Several were found to bind with micromolar affinity to the NK1 and/or NK3 receptor. The conformation of one of the homochiral indanes, (1R)-N-((S)-1-hydroxymethylbenzyl)-1,6-dibenzylindan-1-carboxamide, was analysed by X-ray crystallography and was found to be in an α-helix conformation.

Alanine and N‐methylation scans together with molecular modelling were implemented in order to propose a binding conformation of the minimum active fragment of bombesin (BB), Ac‐BB[7‐14], to the gastrin releasing peptide (GRP) and neuromedin B (NMB) receptors. These data are also used to critically evaluate the previously proposed binding conformations such as x‐helix and antiparallel β‐sheets. This shows that the previously reported conformations do not satisfy the experimental data. A new binding conformation of Ac‐BB[7‐14] is proposed consisting of three consecutive y‐turns followed by a bend and finishing with two y‐turns. This low energy conformation (analogous to a fragment of thymidylate synthase, 2TSC) of bombesin stabilized by five internal hydrogen bonds, and with the side chains of residues Trp8 and Leu13 held on the same side of the peptide, is in agreement with the experimentally observed data. This and the results of molecular modelling may aid in the synthesis of conformationally restricted high affinity bombesin analogues and/or high affinity template‐based GRP or NMB receptor agonists and antagonists.

The design and synthesis of conformationally restrained, non-peptide templates (1,6-disubstituted indanes) which allow the incorporation of two adjacent amino acid side-chains in an orientation similar to that found in alpha-helices is reported.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The reaction of lithiated dithianes 6-8 and 15 and 16 with enantiopure N-sulfonylated aziridines; 1 and 2 leads via regiospecific nucleophilic ring-opening to enantiopure N-tosyl 2-(2'-dithianyl) secondary amines in good to. excellent yields. These compounds may be either desulfonylated or hydrolytically desulfurized to give the corresponding amines 21-24 or carbonyl compounds 25-27 and 28-30 in good yield. In the case of alpha-silaalkanones 31 and 32 produced by these reactions, oxidation furnishes enantiopure 3-tosylamino acids 33 and 34 in good yield.

The ability of three-dimensional quantitative structure-activity relationships (QSARs) derived from classical QSAR descriptors and similarity indices to rationalize the activity of 28 N-terminus fragments of tachykinin NK1 receptor antagonists was examined. Two different types of analyses, partial least squares and multiple regression, were performed in order to check the robustness of each derived model. The models derived using classical QSAR descriptors lacked accurate quantitative and predictive abilities to describe the nature of the receptor-inhibitor interaction. However models derived using 3D QSAR descriptors based on similarity indices were both robust and significantly predictive. The best model was obtained through the statistical analysis of molecular field similarity indices (n = 28, r2 = 0.846, r(cv)2 = 0.737, s = 0.987, PRESS = 7.102) suggesting that electronic and size-related properties are the most relevant in explaining the affinity data of the training set. The overall quality and predictive ability of the models applied to the test set appear to be very high, since the predicted affinities of three test compounds agree with the experimentally determined affinities obtained subsequently within the experimental error of the binding data.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The design and synthesis of conformationally constrained, non-peptide templates (3-substituted pyrrolidines) which allow the incorporation of two adjacent amino acid side-chains in an orientation similar to that found in the i+1 and i+1 positions of a β-turn are reported. The NK2 tachykinin receptor affinity of a Trp-Phe mimetic (7a) which mimics the β-turn in MEN10627 (8), a constrained cyclic hexapeptide, high affinity NK2 tachykinin receptor antagonist, was determined and shown to have no significant binding affinity (NK2, IC50 > 10,000 nM).

Boc(S)Phe(S)PheNH2 (1c) was identified from the biological screening of an in-house dipeptide chemical library as a micromolar NK3 receptor selective ligand (IC50=1150nM). This lead structure has subsequently been developed into a series of potent and selective NK3 receptor antagonists an example of which is the urea derivative Boc(S)Phe(R)αMePheNH(CH2)7NHCOHNH2 (11d, PD157672) (IC50=16nM).

The design and synthesis of conformationally constrained, non-peptide templates (trisubstituted indanes) which allow the incorporation of two adjacent amino acid side-chains plus a third binding group in an orientation similar to that found in alpha-helices is reported. The tachykinin receptor affinity of various Phe-Phe and Trp-Phe mimetics were detemined and several were shown to bind with micromolar affinity.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.