Design, synthesis and biological evaluation of novel bicyclo[1.1.1]pentane-based omega-acidic amino acids as glutamate receptors ligands.

A novel series of bicyclo[1.1.1]pentane-based omega-acidic amino acids, including (2S)- and (2R)-3-(3'-carboxybicyclo[1.1.1]pentyl)alanines (8 and 9), (2S)- and (2R)-2-(3'-carboxymethylbicyclo[1.1.1]pentyl)glycines (10 and 11), and (2S)- and (2R)-3-(3'-phosphonomethylbicyclo[1.1.1]pentyl)glycines (12 and 13), were synthesized and evaluated as glutamate receptor ligands. Among them, (2R)-3-(3'-phosphonomethylbicyclo[1.1.1]pentyl)glycine (13) showed relatively high affinity and selectivity at the NMDA receptor. The results are also discussed in light of pharmacophoric modelling studies of NMDA agonists and antagonists.

Regulation of E2F4 mitogenic activity during terminal differentiation by its heterodimerization partners for nuclear translocation.

E2F/DP heterodimers play a pivotal role in the regulation of cell growth and differentiation. A decrease in E2F/DP activity occurs during cell cycle arrest and differentiation. However, very little is known about the specific role of the various E2F/DP members along the transition from proliferation to terminal differentiation. We have previously shown that E2F4 accounts for the vast majority of the endogenous E2F in differentiating muscle cells. Here, we show that E2F4, which lacks a nuclear localization signal (nls), is distributed in both the nucleus and the cytoplasm, in either asynchronously growing myoblasts or differentiated myotubes. E2F4 nuclear accumulation is induced by the binding in the cytoplasm with specific partners p107, pRb2/p130, and DP3delta, an nls-containing spliced form of DP3, which provide the nls. Although overexpression of E2F4/DP3delta reactivates the cell cycle in quiescent cells, the E2F4 nuclear accumulation induced by pRb2/p130 and p107 correlates with cell growth arrest Moreover, E2F4/DP3delta-induced cell cycle reactivation is efficiently counteracted by either p107 or pRb2/p130 overexpression. Reinduction in quiescent cells of DNA synthesis by E2F1/DP1 overexpression is abrogated by coexpression of pRb and is hampered by MyoD overexpression. Both pRb2/p130 and pRb, as well as MyoD, are up-regulated in myotubes. Accordingly, multinucleated myotubes, which are induced to reenter the S-phase by oncoviral proteins, are refractory to cell cycle reactivation by forced expression of E2F4/DP3delta or E2F1/DP1. Thus, E2F/DP repression represents only one of multiple redundant circuits that control the postmitotic state in terminally differentiated cells and that are targeted by adenovirus E1A and SV40 large T antigen.

Comparative responses to three different types of interferon-alpha in patients with chronic hepatitis C.

We investigated the efficacy and tolerability of three different types of interferon-alpha, administered with the same schedule to naive patients with chronic hepatitis C. One hundred and seven patients with histologically proven chronic hepatitis C were enrolled during a period of three years and randomly divided into three groups, to receive (a) leukocyte-interferon-alpha, 6 MU three times a week for 4 months, followed by 3 MU three times a week for 8 months (Group I); (b) recombinant-IFN-alpha-2a, with the same schedule (Group II); and (c) lymphoblastoid-IFN-alpha-N1, with the same schedule (Group III). All patients were followed-up for 6 months to evaluate the long-term response. The 'Complete Response' rates at the end of treatment were: 50%, 46.1% and 41.6%, in Groups I, II and III, respectively; most patients relapsed after the end of therapy, so that the 'sustained responders' were, after 6 months of follow-up, 18.7%, 23.1% and 19.4%, respectively. Analysis of pre-treatment variables showed that age, ALT and gamma GT serum levels, as well as the prevalence of liver cirrhosis, were lower in the 'sustained responder' group. Four patients were eliminated from the study because of severe adverse events: 1, 2 and 1, in Groups I, II and III, respectively. Our results indicate a similar response rate with the three different types of interferon-alpha, although at baseline, age, serum levels of gamma globulins and the number of patients with cirrhosis-possible negative-risk factors, were higher in Group I.

Prevalence and genomic variability of transfusion transmitted virus in Italian cryptogenic chronic liver disease and healthy blood donors.

BACKGROUND: Infection with transfusion transmitted virus, a new member of the Parvoviridae family, has been found in patients both with chronic and fulminant post-transfusion cryptogenic hepatitis. AIM: To evaluate the prevalence and clinical impact of transfusion transmitted virus infection in Italy. PATIENTS AND METHODS: Studies were carried out on 256 patients and control subjects from three centres from Northern, Central and Southern Italy (92 nonA-nonC chronic hepatitis, 10 acute non fulminant cryptogenic hepatitis, 41 hepatitis C virus-related chronic hepatitis and 113 blood donors). Serum transfusion transmitted virus was detected by nested polymerase chain reaction using two overlapping sets of primers. RESULTS: A total of 52 of the 92 patients (54.3%) with chronic cryptogenic liver disease and 17 of the 41 hepatitis C virus chronic hepatitis patients (41.4%) were transfusion transmitted virus-DNA positive. Transfusion transmitted virus co-infection in hepatitis C virus patients was not associated with either a higher severity of liver histology or higher alanine transaminase levels or signs of cholestasis, transfusion transmitted virus was found in 48 out of 113 (42.4%) blood donors. In the majority of samples, transfusion transmitted virus DNA was detected with only one of the two sets of primers used. Genotyping and phylogenetic analysis performed on 21 randomly selected viral isolates showed the presence of both type 1 and type 2 transfusion transmitted virus and allowed identification of two isolates with high homology to genotype 6, described, so far, mostly in Japan. CONCLUSIONS: Transfusion transmitted virus type 1 and 2 infection is common among blood donors and patients with liver disease in Italy. The pathogenic potential of transfusion transmitted virus type 1 and 2 in nonA-nonC hepatitis patients is unlikely but further studies are needed to evaluate the epidemiological and clinical impact of other transfusion transmitted virus subtypes.

The hepatitis B virus HBx protein inhibits caspase 3 activity.

The hepatitis B virus-encoded HBx protein coactivates transcription of viral and cellular genes, and it is believed to play an important role in hepatitis B virus-related liver cancer. HBx has been shown to alter the coordinated balance between proliferation and programmed cell death, being able to either induce or block apoptosis. Here, we demonstrate for the first time that the HBx is a potent caspase 3 inhibitor. Rat fibroblasts (REV2) and hepatoma cells (Hep) synthesizing the HBx protein were resistant to various apoptotic stimuli such as growth factor depletion, tumor necrosis factor alpha, or anti-Fas antibodies administration. In these cells, HBx prevented DNA fragmentation and cell death in the absence of de novo protein synthesis, with a similar efficiency as the competitive caspase 3 substrates inhibitors VAD-FMK and DEVD-FMK. Protein extracts obtained from the HBx positive cells contained a very low caspase activity, and addition of anti-HBx antibody restored the endogenous caspase activity. To obtain a functional map of the anti-caspase activity of HBx, various cell lines were established that synthesized either N-terminally or C-terminally truncated HBx molecules. These gene dissection experiments revealed that the regions required for the anti-caspase activity overlap with the two known transactivation domains of HBx.

Tumor necrosis factor (TNF) receptor 1 signaling downstream of TNF receptor-associated factor 2. Nuclear factor kappaB (NFkappaB)-inducing kinase requirement for activation of activating protein 1 and NFkappaB but not of c-Jun N-terminal kinase/stress-activated protein kinase.

Like other members of the tumor necrosis factor (TNF) receptor family, p55 TNF receptor 1 (TNF-R1) lacks intrinsic signaling capacity and transduces signals by recruiting associating molecules. The TNF-R1 associated death domain protein interacts with the p55 TNF-R1 cytoplasmic domain and recruits the Fas-associated death domain protein (which directly activates the apoptotic proteases), the protein kinase receptor interacting protein, and TNF receptor-associated factor 2 (TRAF2). TRAF2 has previously been demonstrated to activate both transcription factor nuclear factor kappaB (NFkappaB) and the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) pathway, which in turn stimulates transcription factor activating protein 1 (AP1) mainly via phosphorylation of the c-Jun component. We have investigated the signaling properties of NFkappaB-inducing kinase (NIK), a TRAF2-associated protein kinase that mediates NFkappaB induction. NIK was found to be unable to activate JNK/SAPK, mitogen-activated protein kinase, or p38 kinase. Moreover, NIK was not required for JNK/SAPK activation by TNF-R1, thus representing the first TNF-R1 complex component to dissect the NFkappaB and the JNK/SAPK pathways. Despite being unable to activate JNK/SAPK and mitogen-activated protein kinase, NIK strongly activated AP1 and was required for TNF-R1-induced AP1 activation. Therefore, NIK links TNF-R1 to a novel, JNK/SAPK-independent, AP1 activation pathway.

Evaluation by ultrasound of abdominal lymphadenopathy in chronic hepatitis C.

OBJECTIVE: Abdominal ultrasound has shown a frequent association between abdominal lymphadenopathy (LA) and chronic liver disease, but contradictory data have been reported on its relationship with the main parameters of hepatic function. The aim of this study was to correlate the prevalence of LA in patients who were chronic hepatitis-anti-hepatitis C virus positive prospectively followed-up over the last 3 years and its relationship with biochemical and histological data. METHODS: 136 RIBA II confirmed positive patients with ALT levels >2N were included. None of these had been or was at the time of study on interferon treatment. Ultrasound was performed using a Toshiba SSA 240 A apparatus with a 3.75 MHz convex probe; the operator was unaware of the other results. Diagnosis of chronic hepatitis in all cases was made on biopsy specimens; the histological activity index (HAI) score, according to Knodell, and the grading (G) and staging (S) scores, according to Desmet, were also evaluated. RESULTS: LA was found in 54 out of 136 patients (40%); accordingly, patients were divided into two groups: the LN + ve group included 54 patients (M 33, mean age 48.1+/-11.7 yr) and the LN-ve group included 82 patients (M 69, mean age 45.3+/-11.9 yr). LN + ve patients showed significantly higher serum levels of AST (p < 0.0005), ALT (p < 0.001), gammaGLO (p < 0.05) and gammaGT (p < 0.02) than LN - ve patients. There was a more severe degree of liver disease in LN + ve patients, expressed by the higher HAI (p < 0.002), G (p < 0.002), and S (p < 0.005). The chi2 test for linear association analysis confirmed the trend toward greater histological severity in LN + ve patients (chi2 MH = 10.2; p < 0.002). Logistic regression confirmed the association between the presence of LA and AST (p < 0.02), ALT (p < 0.03), G (p < 0.02), and S (p < 0.02). CONCLUSION: This study showed a moderate prevalence of LA in chronic hepatitis C, lower than that reported in other studies. LA was associated with serum parameters of cytolysis, and above all, with the severity of histological damage.

Intravenous natural beta-interferon in white patients with chronic hepatitis C who are nonresponders to alpha-interferon.

OBJECTIVES: alpha-Interferons (alpha-IFN) have been shown to be effective in the treatment of chronic viral C hepatitis, but their efficacy remains unsatisfactory. Recently natural beta-interferon (beta-IFN) administered by intravenous infusion has been used successfully. METHODS: To evaluate the efficacy and safety of intravenous beta-IFN administration we treated 20 patients with histologically proven chronic hepatitis C who were nonresponders to at least two previous courses of alpha-IFN treatment. All patients received 6 million units (MU) of natural human fibroblast beta-IFN by drip infusion, 6 times per wk for 8 wk and were followed up for 6 months after suspension of treatment. RESULTS: Five patients (25%) had response at the end of treatment; of these patients only one had sustained response. Patients who responded to therapy had lower, although not significantly, baseline levels of HCV RNA, compared with nonresponders. Whereas mean viral load decreased during therapy, only two patients were HCV RNA negative at the end of treatment, but none were at the end of the follow-up period. Genotype 1 was found in 17 cases, genotype 2 was found in one case, and a combination of genotypes 1b and 2a was found in the remaining two cases. Therapy was well tolerated and beta-IFN administration was neither interrupted nor its dosage reduced due to side effects in any of the patients. CONCLUSIONS: Our study shows that intravenous beta-IFN is well tolerated and that the modest results obtained may depend on the brevity of treatment. Consequently, further studies are needed to define the optimum dose, schedule, and duration of treatment to eradicate HCV infection.