UDP-glucuronosyltransferase UGT1A7 genetic polymorphisms in hepatocellular carcinoma: a differential impact according to seropositivity of HBV or HCV markers?

<p>Abstract</p> <p>Background:</p> <p>We conducted a case-control study to evaluate the role of UDP-glucuronosyltransferase 1A7 (UGT1A7) polymorphisms in the onset of hepatocellular carcinoma (HCC).</p> <p>Methods:</p> <p>The study included 165 patients with HCC, 134 with cirrhosis and 142 controls without liver disease, matched for age and hospital. All were men younger than 75 years. HCC and cirrhosis patients were stratified according to time since cirrhosis diagnosis.</p> <p>Results:</p> <p>We found a positive association between the UGT1A7*3/*3 genotype and HCC when the comparison was restricted to patients whose disease was of viral origin [OR = 3.4 (0.3–45)] but a negative association when it included only alcoholic patients [OR = 0.1 (0.02–0.6), p = 0.01].</p> <p>Conclusion:</p> <p>Our study shows that UGT1A7 may play a role in hepatocellular carcinogenesis and that this role may differ according to the primary cause of the cirrhosis.</p

Carbon-bridged diphosphine ligands for chromium-catalysed ethylene tetramerisation and trimerisation reactions

The use of carbon-bridged diphosphine ligands in chromium-catalysed ethylene tri- and tetramerisation reactions has been investigated. Two- and three-carbon spacer ligands all showed activity for selective oligomerisation, with a structure-selectivity correlation between P-Cr-P bite angle and 1-octene: 1-hexene ratio evident. Activated chromium complexes of single carbon spacer diphosphines were also shown to be effective tetramerisation catalysts, provided that the ligand is innocent under the conditions of catalyst activation. A catalyst with the bis(diphenylphosphino)benzene ligand was found to be exceptionally active, although the combined 1-hexene and 1-octene selectivity was lower than with the best diphosphinoamine (PNP) ligands. The yield losses to by-products can to an extent be minimised by the use of high reaction temperatures and pressures. Unlike with the PNP-based systems, attempts to activate the Cr/bis(diphenylphosphino)benzene catalyst in situ from a chromium salt and free ligand resulted in low activity and high polymer formation. The effect of different phosphine substitution on catalyst selectivity was explored. Steric constraints around the catalytic centre (ortho-alkylphenyl phosphines) resulted in a shift towards 1-hexene formation, as with PNP catalysts. Additionally, the basicity of the phosphines appears to influence catalyst selectivity, with alkyl phosphines favouring trimerisation. An interplay between phosphine basicity and bridge structure is in evidence, however, as a catalyst containing a ligand with both basic phosphine atoms and a small bite angle was shown to be selective towards I-octene. (c) 2007 Elsevier B.V. All rights reserved.</p