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RationalePrevious studies have shown that blockade of metabotropic glutamate 5 receptors (mGluR5) results in inhibition of nicotine self-administration in experimental animals. However, these studies have not established the behavioural mechanisms which mediate these effects or the extent to which the effects of mGluR5 antagonism on nicotine self-administration reflect a selective attenuation of nicotine reinforcement.ObjectivesTo investigate the effects of antagonising mGluR5 receptors on psychopharmacological responses to nicotine measured using conditioned and unconditioned behaviours.Results2-Methyl-6-(phenylethynyl)-pyridine (MPEP) significantly (P < 0.01) reduced nicotine self-administration and attenuated (P < 0.01) the ability of non-contingent nicotine to enhance the reinforcing properties of a weak reinforcer (extinguishing the house light in an operant chamber). It also attenuated (P < 0.05) the much lower levels of responding for this reinforcer measured in control animals treated with saline. MPEP did not attenuate the increase in locomotor activity induced by acute and repeated nicotine in animals habituated on the test day to the test environment. Furthermore, it had no significant effects on responding for a palatable food reward. By contrast, MPEP significantly reduced (P < 0.001) conditioned locomotor stimulation evoked by pairing nicotine with a specific environment.ConclusionThe results are consistent with the hypothesis that mGluR5 receptors play an important role in mediating the effects of contextual cues in conditioned behavioural responses to nicotine.

The aim of this study was to evaluate the distribution and clinical significance of hepatitis C virus (HCV) genotypes in European patients with compensated cirrhosis due to hepatitis C (Child class A) seen at tertiary referral centres. HCV genotypes were determined by genotype-specific primer PCR in 255 stored serum samples obtained from cirrhotics followed for a median period of 7 years. Inclusion criteria were biopsy-proven cirrhosis, absence of complications of cirrhosis and exclusion of all other potential causes of chronic liver disease. The proportion of patients with types 1b, 2, 3a, 1a, 4 and 5 were 69%, 19%, 6%, 5%, 0.5% and 0.5%, respectively. Kaplan-Meier 5-year risk of hepatocellular carcinoma (HCC) was 6% and 4% for patients infected by type 1b and non-1b, respectively (P=0.8); the corresponding figures for decompensation were 18% and 7% (P=0.0009) and for event-free survival were 79% and 89% (P=0.09), respectively. After adjustment for baseline clinical and serological features, HCV type 1b did not increase the risk for HCC [adjusted relative risk=1.0 (95% confidence interval=0.47-2.34)], whereas it increased the risk for decompensation by a factor of 3 (1.2-7.4) and decreased event-free survival by a factor of 1.7 (0.9-3.10). In conclusion, type 1b and, to a lesser extent, type 2, are the most common HCV genotypes in European patients with cirrhosis. HCV type 1b is not associated with a greater risk for HCC, but increases the risk for decompensation by threefold in patients with cirrhosis.

Chronic hepatitis may progress to cirrhosis and hepatocellular carcinoma (HCC). HCC represents one of the most common human cancers. Incidence rates for this tumor vary widely on a worldwide, suggesting that environmental factors such as infectious microorganisms, carcinogens, or nutrition play a role in its pathogenesis. Several Helicobacter spp. colonize the liver of animals and induce hepatitis. The aim of this study was to determine whether Helicobacter infection was associated with HCV-related liver diseases in humans. Liver tissue samples, including biopsy and surgically excised tissues, were collected from patients positive for hepatitis C viruses (HCV) RNA in the serum. Genomic DNA was extracted from sections of formalin-fixed paraffin-embedded tissues by using the QIAamp Tissue Kit and subjected to polymerase chain reaction (PCR) analysis using two sets of Helicobacter-specific 16S ribosomal RNA primers. To identify positive samples for H. pylori, a set of primers specific for a conserved region in the H. pylori vacA gene were also used. The patients' H. pylori status was determined by ELISA. Forty-one patients (mean age 54.9, range 19-78 years; 24 men) were studied. Thirty patients had chronic viral hepatitis (CH) without (N = 18) or with (N = 12) cirrhosis (CIR), and 11 patients had HCC. Anti-H. pylori IgG was detected in 54%. The expected 422- and 210-bp fragments of Helicobacter 16S rRNA were amplified from 27% of liver samples, including 17% of CH-CIR and 55% of HCC (P = 0.004). The vacA sequence was amplified in 10 of 41(24%) samples (27% of those with HCC). These data confirm the presence of H. pylori DNA sequences in human liver and suggest an association of Helicobacter spp. with HCV-related chronic liver diseases. Further studies are needed to ascertain whether Helicobacter spp. infection plays a role in the development of HCC.