The diagnostic value of biomarkers (SteatoTest) for the prediction of liver steatosis

Background

Biopsy is the usual gold standard for liver steatosis assessment. The aim of this study was to identify a panel of biomarkers (SteatoTest), with sufficient predictive values, for the non-invasive diagnosis of steatosis in patients with or without chronic liver disease. Biomarkers and panels were assessed in a training group of consecutive patients with chronic hepatitis C and B, alcoholic liver disease, and non-alcoholic fatty liver disease, and were validated in two independent groups including a prospective one. Steatosis was blindly assessed by using a previously validated scoring system.

Results

310 patients were included in the training group; 434 in three validation groups; and 140 in a control group. SteatoTest was constructed using a combination of the 6 components of FibroTest-ActiTest plus body mass index, serum cholesterol, triglycerides, and glucose adjusted for age and gender. SteatoTest area under the ROC curves was 0.79 (SE = 0.03) in the training group; 0.80 (0.04) in validation group 1; 0.86 (0.03) in validation group 2; and 0.72 (0.05) in the validation group 3 – all significantly higher than the standard markers: γ-glutamyl-transpeptidase or alanine aminotransferase. The median SteatoTest value was 0.13 in fasting controls; 0.16 in non-fasting controls; 0.31 in patients without steatosis; 0.39 in grade 1 steatosis (0–5%); 0.58 in grade 2 (6–32%); and 0.74 in grade 3–4 (33–100%). For the diagnosis of grade 2–4 steatosis, the sensitivity of SteatoTest at the 0.30 cut-off was 0.91, 0.98, 1.00 and 0.85 and the specificity at the 0.70 cut-off was 0.89, 0.83, 0.92, 1.00, for the training and three validation groups, respectively.

Conclusion

SteatoTest is a simple and non-invasive quantitative estimate of liver steatosis and may reduce the need for liver biopsy, particularly in patients with metabolic risk factor.

Telomerase-dependent virotherapy overcomes resistance of hepatocellular carcinomas against chemotherapy and tumor necrosis factor-related apoptosis-inducing ligand by elimination of Mcl-1

Hepatocellular carcinomas (HCC) are drug-resistant tumors that frequently possess high telomerase activity. It was therefore the aim of our study to investigate the potential of telomerase-dependent virotherapy in multimodal treatment of HCC. In contrast to normal liver, HCC xenografts showed high telomerase activity, resulting in tumor-restricted expression of E1A by a telomerase-dependent replicating adenovirus (hTERT-Ad). Neither tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or chemotherapy alone nor the combined treatment with both agents resulted in significant destruction of HCC cells. Application of hTERT-Ad at low titers was also not capable to destroy HCC cells, but telomerase-dependent virotherapy overcame the resistance of HCC against TRAIL and chemotherapy. The synergistic effects are explained by a strong down-regulation of Mcl-1 expression through hTERT-Ad that sensitizes HCC for TRAIL- and chemotherapy-mediated apoptosis. To investigate whether down-regulation of Mcl-1 alone is sufficient to explain synergistic effects observed with virotherapy, Mcl-1 expression was inhibited by RNA interference. Treatment with Mcl-1-siRNA significantly enhanced caspase-3 activity after chemotherapy and TRAIL application, confirming that elimination of Mcl-1 is responsible for the drug sensitization by hTERT-Ad. Consistent with these results, heterologous overexpression of Mcl-1 significantly reduced the sensitization of hTERT-Ad transduced cells against apoptosis-inducing agents. Chemotherapy did not interfere with quantitative hTERT-Ad production in HCC cells. Whereas hTERT-Ad virotherapy alone was only capable to inhibit the growth of Hep3B xenografts, virochemotherapy resulted in vast destruction of the drug-resistant HCC. In conclusion our data indicate that telomerase-dependent virotherapy is an attractive strategy to overcome the natural resistance of HCC against anticancer drugs by elimination of Mcl-1.

[Improvement of ultrasound education by simulator training]

Ultrasound education is complicated by varying quantities and qualities of specific pathologies resulting from distinct patient collectives. Furthermore, under current clinical conditions ultrasound educators as well as trainees frequently lack the time necessary for a sufficient ultrasound education. Finally, current ultrasound education materials including "gold standard" images are not ideally suited for teaching scanning three-dimensional pathologies. An improvement of ultrasound education is feasible by training ultrasound trainees on an ultrasound simulator we developed. By using this simulator as well in the classical beginner and advanced level courses as in focused courses of abdominal emergencies or general practice for instance, ultrasound trainees are able to practice scanning of numerous well defined pathologies under realistic conditions.

Protein transduction domains fused to virus receptors improve cellular virus uptake and enhance oncolysis by tumor-specific replicating vectors

Expression of cellular receptors determines viral tropism and limits gene delivery by viral vectors. Protein transduction domains (PTDs) have been shown to deliver proteins, antisense oligonucleotides, liposomes, or plasmid DNA into cells. In our study, we investigated the role of several PTD motifs in adenoviral infection. When physiologically expressed, a PTD from human immunodeficiency virus transactivator of transcription (Tat) did not improve adenoviral infection. We therefore fused PTDs to the ectodomain of the coxsackievirus-adenovirus receptor (CAR(ex)) to attach PTDs to adenoviral fiber knobs. CAR(ex)-Tat and CAR(ex)-VP22 allowed efficient adenoviral infection in nonpermissive cells and significantly improved viral uptake rates in permissive cells. Dose-dependent competition of CAR(ex)-PTD-mediated infection using CAR(ex) and inhibition experiments with heparin showed that binding of CAR(ex)-PTD to both adenoviral fiber and cellular glycosaminoglycans is essential for the improvement of infection. CAR(ex)-PTD-treated adenoviruses retained their properties after density gradient ultracentrifugation, indicating stable binding of CAR(ex)-PTD to adenoviral particles. Consequently, the mechanism of CAR(ex)-PTD-mediated infection involves coating of the viral fiber knobs by CAR(ex)-PTD, rather than placement of CAR(ex) domains on cell surfaces. Expression of CAR(ex)-PTDs led to enhanced lysis of permissive and nonpermissive tumor cells by replicating adenoviruses, indicating that CAR(ex)-PTDs are valuable tools to improve the efficacy of oncolytic therapy. Together, our study shows that CAR(ex)-PTDs facilitate gene transfer in nonpermissive cells and improve viral uptake at reduced titers and infection times. The data suggest that PTDs fused to virus binding receptors may be a valuable tool to overcome natural tropism of vectors and could be of great interest for gene therapeutic approaches.

Neue Konzepte in der gastroenterologischen Sonographieausbildung durch Schulung am Ultraschallsimulator

Ultrasound is one of the most important imaging methods in medicine. However, ultrasound education is complicated by varying quantities and qualities of specific pathologies resulting from distinct patient collectives. Furthermore, under current clinical conditions ultrasound educators as well as trainees frequently lack the time necessary for a sufficient ultrasound education. Finally, current ultrasound education materials including "gold standard" images are not ideally suited for teaching scanning three-dimensional pathologies. In a direct cross over study we recently proved, that the ultrasound simulator we developed simulated the real patient examination reliably and reproducibly. By using this simulator as well in the classical beginner and advanced level courses as in focused courses of abdominal emergencies for instance, ultrasound trainees are able to practice scanning of well defined pathologies under realistic conditions, which has not been possible before. Furthermore, the ultrasound simulator is well suited for a structured ultrasound training in single hospitals as well as in continuous medical education. Finally, objective, standardized ultrasound quality control has become possible with the simulator.

Post-hatch activity-dependent modulation of visual asymmetry formation in pigeons

The embryonically induced visual lateralization in pigeons can be modified by occlusion of one eye after hatching. Here we show that this deprivation effect could be also attained by short-term blocking of retinal activity with tetrodotoxin (TTX), leading to a dominance of the ipsilateral hemisphere in a visual discrimination task. This lateralization pattern resulted from a performance increase conveyed by the non-deprived hemisphere, while performance with the TTX-injected eye did not differ from that of saline-injected controls. Thus, post-hatch modulation of visual lateralization is mediated by TTX-sensitive, activity-dependent neuronal mechanisms. The transient silencing of one visual input alters the activity balance between the left and right eye system, enhancing visuoperceptive skills in the relatively higher active hemisphere.

Hepatic artery embolization for treatment of patients with hereditary hemorrhagic telangiectasia and symptomatic hepatic vascular malformations

At present there is no established therapy for treating patients with hereditary hemorrhagic telangiectasia (HHT) and symptomatic hepatic involvement. We present the results of a prospective study with 15 consecutive patients who were treated with staged hepatic artery embolization (HAE). Branches of the hepatic artery were selectively catheterized and embolized in stages using polyvinyl alcohol particles (PVA) and platinum microcoils or steel macrocoils. Prophylactic antibiotics, analgesics and anti-emetics were administered after every embolization. Clinical symptomatology and cardiac output were assessed before and after therapy as well as at the end of follow-up (median 28 months; range 10-136 months). Five patients had abdominal pain and four patients had symptoms of portal hypertension. The cardiac output was raised in all patients, with cardiac failure being present in 11 patients. After treatment, pain resolved in all five patients, and portal hypertension improved in two of the four patients. The mean cardiac output decreased significantly ( P<0.001) from 12.57+/-3.27 l/min pre-treatment to 8.36+/-2.60 l/min at the end of follow-up. Symptoms arising from cardiac failure resolved or improved markedly in all but one patient. Cholangitis and/or cholecystitis occurred in three patients of whom two required a cholecystectomy. One patient with pre-existent hepatic cirrhosis died as a complication of the procedure. Staged HAE yields long-term relief of clinical symptoms in patients with HHT and hepatic involvement. Patients with pre-existing hepatic cirrhosis may be poor candidates for HAE.

Tumor-specific adenoviral gene therapy: transcriptional repression of gene expression by utilizing p53-signal transduction pathways

Adenoviral gene expression that is repressed by p53 in nontransformed cells could provide a tumor-specific gene therapy approach for a large subset of tumors. Adenoviral infection in vivo induces stabilization of p53, which can be utilized for a strategy that includes p53-dependent expression of a transcriptional repressor and a target promoter,which is highly susceptible for transcriptional repression. Therefore, we constructed different versions of CMV-promoters (CMVgal) with binding sites for GAL4-DBD and investigated 11 GAL4-DBD fusion proteins to elucidate the most effective repressor domain to silence CMVgal activity. The transcriptional repressor GAL4-KRAB-A under control of a p53-dependent promoter facilitates strong CMVgal-mediated gene expression specifically in p53 mutant cells by a double-recombinant adenoviral vector (Ad-RGCdR). GAL4-KRAB-A mediates strong transcriptional repression of Ad-RGCdR in p53 wild-type cells, which could be further enhanced by preactivation of p53-signalling following low-dose chemotherapy prior to adenoviral infection. By utilizing p53 signalling involved in chemotherapy and adenoviral infection, more than 99% of Ad-RGCdR gene expression could be repressed in p53 wild-type cells. Controlled gene expression from CMVgal promoters by transcriptional repression utilizing functional p53 signalling thus provides a very effective tool for tumor-specific adenoviral gene therapy.

Simulation of abdomen sonography. Evaluation of a new ultrasound simulator

AIM

We developed and evaluated a simulator for the sonography of the abdomen in order to improve the teaching quality in sonography training.

METHOD

Eleven medicine residents who had received 4 to 12 months full time sonography training performed ultrasound examinations of the right upper quadrant in 5 consecutive patients and in 5 simulator cases. The correctness of their findings and the time required for the examinations were measured. The subjective confidence in their findings and the handling of the ultrasound machines were rated on a visual analogue scale.

RESULTS

During patient ultrasound examination 75 % (SEM 9%) of all pathologic findings were recognized by the residents, whereas 71 % (SEM 8%) of the pathologies of the simulator cases were found. This minimal difference was not significant in the paired, two sided t-test (p = 0.15). Severe pathologies did not escape detection. The time required for patient examination(10.57 min, SEM 3.25 min) was not significantly different (p = 0.53) to the time required for the simulator cases (9.59 min, SEM 2.98 min). The subjective confidence in the sonographic findings did not differ significantly (p = 0.39) between the real patient situation (68%, SEM 6%) and the simulation (64%, SEM 12 %). Only the handling of the ultrasound machines was judged to be significantly better (p=0.008) than the simulator (74%,SEM 7% vs. 61 %, SEM 12%).

CONCLUSION

In this first direct crossover comparison between real patient sonography and simulator based scanning we proved that the simulator we developed simulates the real patient examination reliably and reproducibly.

Biochemical surrogate markers of liver fibrosis and activity in a randomized trial of peginterferon alfa-2b and ribavirin

Liver fibrosis and activity indexes were validated in patients infected by hepatitis C virus (HCV) nontreated and treated by interferon. The aim was to validate their usefulness as surrogate markers of histologic features using the data of a randomized trial of combination peginterferon alfa-2b and ribavirin. Three hundred fifty-two patients who had had 2 interpretable liver biopsies and stored serum sample before and after treatment were selected. Two hundred eight patients received peginterferon alfa-2b 1.5 mcg per kg and ribavirin and 144 patients interferon alfa-2b 3 MU three times a week and ribavirin for 48 weeks. A fibrosis and an activity index combining 5 and 6 biochemical markers were assessed at baseline and at end of follow-up (24 weeks after treatment). The biochemical markers have significant predictive values both for the diagnosis of fibrosis and for activity. For the diagnosis of bridging fibrosis and/or moderate necroinflammatory activity, the area under the receiver operating characteristics curve of the activity index was 0.76 +/- 0.03 at baseline and 0.82 +/- 0.02 at end of follow-up. A cutoff of activity index at 0.30 (range, 0.00-1.00) had 90% sensitivity and 88% positive predictive value for the diagnosis of bridging fibrosis or moderate necroinflammatory activity. Sensitivity analyses with biopsy specimens of size greater than 15 mm suggest that a part of discordances between biochemical markers and histology were due to biopsy specimen sampling error. In conclusion, these biochemical markers of fibrosis and activity could be used as surrogate markers for liver biopsy in patients with chronic hepatitis C, both for the initial evaluation and for follow-up.

Effect of treatment with peginterferon or interferon alfa-2b and ribavirin on steatosis in patients infected with hepatitis C

It has been suggested that hepatitis C virus (HCV) and especially genotype 3 is associated with steatosis. We assess the effect of treatment with peginterferon or interferon alfa-2b and ribavirin on steatosis. We analyzed 1,428 naïve patients included in a randomized trial. A single pathologist scored steatosis at baseline and 24 weeks after the treatment. At baseline, steatosis was present in 935 of 1,428 patients (65%), including 175 (83%) of 210 patients with genotype 3 versus 760 (62%) of 1,218 with other genotypes (P <.001). The variables associated with steatosis in logistic regression were genotype 3 (P <.001), triglycerides greater than 1.7 mmol/L (P <.001), body mass index greater than 27 (P <.04), age greater than 40 years (P <.001), and septal fibrosis (P =.007). In genotype 3-infected patients, steatosis was associated with high viral load and with lower serum cholesterol. Steatosis was associated with lower sustained response rate, even after taking into account other factors (P <.001). Among virologic responders, steatosis was much improved in genotype 3, improvement of at least 1 grade in 77%, and disappearance in 46% compared with other genotypes, 46% and 29%, respectively (P <.001 both comparisons). In genotype 3 responders, the baseline low serum cholesterol was corrected by treatment (P <.001). Steatosis was associated with HCV genotype 3, triglycerides, high body mass index, age, fibrosis stage, and lower virologic response to treatment. In conclusion, sustained disappearance of the virus is associated with reduction of steatosis in genotype 3 as well as a correction of baseline low serum cholesterol.

A telomerase-dependent conditionally replicating adenovirus for selective treatment of cancer

The catalytic component of human telomerase reverse transcriptase (hTERT) is not expressed in most primary somatic human cells, whereas the majority of cancer cells reactivate telomerase by transcriptional up-regulation of hTERT. Several studies demonstrated that the hTERT promoter can be used to restrict gene expression of E1-deleted replication defective adenoviral vectors to telomerase-positive cancer cells. In this study, a conditionally replicating adenovirus (hTERT-Ad) expressing E1A genes under control of a 255-bp hTERT-promoter was constructed. Additionally, an internal ribosomal entry site-enhanced green fluorescent protein cassette was inserted downstream of the E1B locus to monitor viral replication in vivo. Adenoviral replication of hTERT-Ad and enhancement of enhanced green fluorescent protein expression could be observed in all investigated telomerase-positive tumor cell lines. In contrast, hTERT-Ad infection of telomerase-negative primary human hepatocytes did not result in significant replication. The capability of hTERT-Ad to induce cytopathic effects in tumor cells was comparable with that of adenovirus wild type and significantly higher compared with ONYX-015, regardless of the p53 status of the tumor cells. Single application of low-dose hTERT-Ad to tumor xenografts led to significant inhibition of tumor growth, confirming the potential therapeutic value of conditionally replicative adenoviral vectors. These in vivo experiments also revealed that hTERT-Ad-mediated oncolysis was more efficient than ONYX-015 treatment. These results demonstrate that expression of E1A under transcriptional control of the hTERT promoter is sufficient for effective telomerase-dependent adenovirus replication as a promising perspective for the treatment of the majority of epithelial tumors.

[Ultrasound of acute abdomen]

Ultrasound is an important tool in the diagnosis of acute abdominal pain, which is mainly caused by gastrointestinal diseases. This article gives an overview on the important differential diagnosis related to pain localization. Sonomorphological signs and their sensitivity and specificity are discussed. In contrast to other imaging methods ultrasound is hand guided. The present article differentiates the diagnostic capability of ultrasonic diagnosis depending on technical equipment and sonographer's educational level. These facts are important to stabilize the position of ultrasound in the ensemble of other imaging methods. The use of mobile ultrasound machines and an improved training (e.g. by computer assisted sonosimulator systems) will lead to an increasing importance of ultrasound.

A comparison of fibrosis progression in chronic liver diseases

BACKGROUND/AIMS

No study has compared the liver fibrosis progression rates among chronic liver diseases and the risk factors in order to better organize screening strategies.

METHODS

A total of 4852 patients were retrospectively studied (chronic hepatitis C (HCV) [n=2313], human immunodeficiency virus (HIV)-HCV co-infection (HIV-HCV [n=180]), hepatitis B (HBV [n=777]), alcoholic liver disease (ALD [n=701]), primary biliary cirrhosis (PBC [n=406]), genetic hemochromatosis (GH [n=383]) auto-immune hepatitis (AIH [n=57]) and delta hepatitis (n=35). The fibrosis progression rates were estimated from birth and from the date of exposure, when known, to the first biopsy.

RESULTS

There were highly significant differences in the rates of fibrosis progression, the most rapid being HIV-HCV co-infection (50% cirrhosis percentile at 52 years of age) and the slowest being PBC (50% cirrhosis percentile at 81 years). There was an acceleration of fibrosis progression with aging. Fibrosis progression was slower in females compared with males for HCV, HBV, GH, and PBC. In contrast, in ALD, the fibrosis progression was more rapid in females.

CONCLUSIONS

Rates of fibrosis progression differ markedly between the predominant causes of chronic liver disease, and according to age and gender. Patients with HIV-HCV co-infection are at particularly high risk of fibrosis progression.

Peginterferon alpha-2a (40kD) [Pegasys] improves HR-QOL outcomes compared with unmodified interferon alpha-2a [Roferon-A]: in patients with chronic hepatitis C

BACKGROUND

Use of unmodified interferon alpha-2a in chronic hepatitis C is associated with impaired health-related quality of life during therapy. Treatment with peginterferon alpha-2a (40kD) provides an improved sustained response over unmodified interferon alpha-2a.

OBJECTIVES

To compare health-related quality of life during treatment for patients receiving peginterferon alpha-2a (40kD) [Pegasys] versus unmodified interferon alpha-2a [Roferon].

DESIGN

A randomised, international, multicentre, open-label, parallel group study.

SETTING

36 centres worldwide.

PATIENTS

Interferon-naïve patients (n = 531) with chronic hepatitis C.

INTERVENTIONS

Peginterferon alpha-2a (40kD) 180 mirog once a week (n = 267) for 48 weeks or unmodified interferon alpha-2a 6 million IU three times a week for 12 weeks followed by 36 weeks of 3 million IU three times a week (n = 264).

MEASUREMENTS

Fatigue Severity Scale and 36-item Short-Form Health Survey (SF-36).

RESULTS

At weeks 2 and 12, differences favouring peginterferon alpha-2a (40kD) were seen on seven of eight domains and both summary scores of the SF-36 (p < 0.05 to p < 0.01). At weeks 2, 12 and 24, patients receiving peginterferon alpha-2a (40kD) had less disabling fatigue (p < 0.01) than those receiving unmodified interferon alpha-2a.

CONCLUSION

Treatment with peginterferon alpha-2a (40kD) is associated with less disabling fatigue and less impairment in patient functioning and well-being during treatment than unmodified interferon alpha-2a. In addition to safety and efficacy, the impact on health-related quality of life may be an important consideration for physicians when selecting an optimal treatment regimen.

Adherence to combination therapy enhances sustained response in genotype-1-infected patients with chronic hepatitis C

BACKGROUND & AIMS

Patient adherence to prescribed antiviral therapy in human immunodeficiency virus infection enhances response. We evaluated the impact of adherence to combination therapy with interferon or peginterferon plus ribavirin in chronic hepatitis C patients.

METHODS

We assessed the effect of dose reduction on sustained virologic response (SVR) from prior trials with interferon alpha-2b plus ribavirin (n = 1010) or peginterferon alpha-2b 1.5 microg/kg/week plus ribavirin (n = 511). The actual treatment administered was verified from drug dispensing/return records and patient diaries. Two groups were defined: (1) patients who received >or=80% of both their total interferon and ribavirin doses for >or=80% of the expected duration of therapy and (2) patients who received reduced doses (<80% of one or both drugs for >or=80% of the expected duration of therapy). A statistical model provided comparative estimates of the response rates in compliant patients.

RESULTS

Most patients were at least 80% compliant with interferon alpha-2b/ribavirin or peginterferon alpha-2b/ribavirin therapy and had SVR rates of 52% and 63%, respectively, for the 2 regimens. This was most apparent for HCV-1-infected patients. The impacts of adherence on efficacy from subgroup analysis and the statistical modeling approach were similar.

CONCLUSIONS

HCV-1-infected patients who can be maintained on >80% of their interferon or peginterferon alpha-2b and ribavirin dosage for the duration of treatment in the setting of a clinical trial exhibit enhanced sustained response rates. Our results suggest that adherence will enhance the likelihood of achieving an initial virologic response. Adherence beyond 12-24 weeks will be advantageous only for those patients who have achieved such an early virologic response.

Gene therapy by intrahepatic and intratumoral trafficking of p53-VP22 induces regression of liver tumors

BACKGROUND & AIMS

VP22-mediated intercellular transport provides an approach to deliver functional chimeric proteins into a high percentage of target cells. The aim of this study was to evaluate the efficacy of p53/VP22 fusion protein in gene therapy of liver tumors.

METHODS

Expression vectors of N- and C-terminal fusion proteins of p53 and VP22 were subcloned and transcriptional properties of chimeric proteins were assessed by luciferase assays. Adenoviral vectors expressing p53 wild type (AdGFP/p53wt) and p53-VP22 (AdGFP/p53-VP22) were generated to investigate the VP22-mediated spreading in normal liver and in liver tumors in vivo by green fluorescent protein fluorescence and p53 immunohistochemistry. Gene therapy was investigated in subcutaneous and preclinical orthotopic animal tumor models after subcutaneous and intra-arterial administration of the adenoviruses, and tumor growth was assessed by direct calibration and magnetic resonance imaging.

RESULTS

p53-VP22 showed enhanced transcriptional activity compared with p53 wild type. VP22-mediated intercellular transport of p53 could be observed in the normal liver and in liver tumors in vivo and was correlated with increased antitumor efficacy of gene therapy and improved survival of the animals.

CONCLUSIONS

Fusion of VP22 to p53 strongly improves the results of p53 replacement gene therapy. Furthermore, the demonstrated VP22-mediated intercellular transport in the liver could be important for other strategies in liver gene therapy, providing a tool for enhancing the effect of gene therapy in liver diseases such as metabolic disorders or viral hepatitis.

Restoration of replication phenotype of lamivudine-resistant hepatitis B virus mutants by compensatory changes in the "fingers" subdomain of the viral polymerase selected as a consequence of mutations in the overlapping S gene

The introduction of lamivudine (LMV) for the treatment of chronic hepatitis B infection has been an important advance in the management of this disease. However, the long-term efficacy of LMV may become limited by the emergence of antiviral-resistant hepatitis B virus (HBV) mutants. The two most common LMV-resistant mutants produce changes in the viral polymerase protein (rt) of rtM204I and rtL180M/M204V (previously rtM550I and rtL526M/M550V). A number of studies have demonstrated that these HBV mutants appear to be replication impaired, both in vitro and in vivo. The detection and selection of compensatory mutations in the polymerase protein that restore the replication phenotype of these HBV mutants have been poorly described to date. The effects of mutations in the fingers subdomain of the viral polymerase protein arising as a consequence of vaccine and hepatitis B immune globulin (HBIg) selected changes in the overlapping envelope gene (S), and a determinant of the hepatitis Bs antigen (HBsAg) were analyzed in vitro. The LMV-resistant HBV mutants rtM204I and rtL180M/M204V produced substantially weaker HBV DNA replicative intermediate signals by Southern blot analysis and less total intracellular HBV DNA by real-time PCR compared to wild-type virus. The viral polymerase protein of these mutants produced little detectable radiolabeled HBV DNA in an endogenous polymerase assay. In contrast, the HBV a determinant HBIg/vaccine escape mutants sP120T, sT123N, sG145R, and sD144E/G145R (that produce rtT128N, Q130P, rtW153Q, and rtG153E respectively) yielded as much virus as wild-type HBV while the sM133L (rtY141S) mutant was replication impaired. Two of these mutants, rtT128N and rtW153Q, when introduced into a replication-competent HBV vector containing the rtL180M/M204V polymerase mutation restored the replication phenotype of this LMV-resistant mutant. These viruses produced levels of intracellular HBV DNA as determined by Southern blot and real-time PCR that were comparable to those of wild-type HBV, indicating that the changes in the fingers subdomain were able to compensate for the reduced replication of the LMV-resistant mutations. Since these viruses carry mutations in the a determinant of HBsAg that may potentially decrease the ability of anti-HBs antibody to neutralize these viruses, these HBV mutants also have the potential to behave as vaccine escape mutants.

VP22-mediated intercellular transport of p53 in hepatoma cells in vitro and in vivo

The capacity of VP22 chimeric proteins to spread from the primary transduced cell to surrounding cells could improve gene therapy approaches, especially in cancer therapy. However, there are conflicting data about VP22-mediated intercellular trafficking in different studies. To assess the role of VP22 in gene therapy of hepatocellular carcinomas (HCCs) we constructed expression vectors for N- and C-terminal versions of VP22-p53 fusion proteins and investigated the VP22-mediated shuttle effect in hepatoma cells by cotransfection experiments. VP22-mediated trafficking was not detectable in hepatoma cells in vitro by fluorescence microscopy, but reporter gene transactivation assays demonstrated intercellular trafficking of functional VP22-p53 in vitro. For in vivo experiments, the recombinant adenoviruses Ad5CMVp53 and Ad5CMVp53-VP22 were constructed. In contrast to the in vitro experiments intercellular trafficking of VP22-p53 could be observed in subcutaneous tumors of hepatoma cells by fluorescence microscopy, indicating a stronger shuttle effect in solid tumors compared to cell culture experiments. Because spread of p53-VP22 in liver tumors was correlated with enhanced apoptosis of hepatoma cells VP22-mediated trafficking of potential therapeutic proteins may improve the results of gene therapy of HCCs.

Impact of pegylated interferon alfa-2b and ribavirin on liver fibrosis in patients with chronic hepatitis C

BACKGROUND & AIMS

Liver fibrosis is an important prognostic factor in patients with hepatitis C. The effect of pegylated (PEG) interferon alone or its combination with ribavirin on fibrosis has not been established.

METHODS

We pooled individual data from 3010 naive patients with pretreatment and posttreatment biopsies from 4 randomized trials. Ten different regimens combining standard interferon, PEG interferon, and ribavirin were compared. The impact of each regimen was estimated by the percentage of patients with at least 1 grade improvement in the necrosis and inflammation (METAVIR score), the percentage of patients with at least 1 stage worsening in fibrosis METAVIR score, and by the fibrosis progression rate per year.

RESULTS

Necrosis and inflammation improvement ranged from 39% (interferon 24 weeks) to 73% (optimized PEG 1.5 and ribavirin; P < 0.001). Fibrosis worsening ranges from 23% (interferon 24 weeks) to 8% (optimized PEG 1.5 and ribavirin; P < 0.001). All regimens significantly reduced the fibrosis progression rates in comparison to rates before treatment. The reversal of cirrhosis was observed in 75 patients (49%) of 153 patients with baseline cirrhosis. Six factors were independently associated with the absence of significant fibrosis after treatment: baseline fibrosis stage (odds ratio [OR] = 0.12; P < 0.0001), sustained viral response (OR = 0.36; P < 0.0001), age < 40 years (OR = 0.51; P < 0.001), body mass index < 27 kg/m(2) (OR = 0.65; P < 0.001), no or minimal baseline activity (OR = 0.70; P = 0.02), and viral load < 3.5 millions copies per milliliter (OR = 0.79; P = 0.03).

CONCLUSIONS

PEG-interferon and ribavirin combination significantly reduces the rate of fibrosis progression in patients with hepatitis C.

p53 mutation pattern and expression of c-erbB2 and c-met in gastric cancer: relation to histological subtypes, Helicobacter pylori infection, and prognosis

The molecular mechanisms of Helicobacter pylori associated tumor development are poorly understood. The spectra of genetic alterations in neoplasms may provide clues to the molecular carcinogenesis of a tumor and may be relevant for the prognosis of the patients. We investigated the p53 mutation pattern and the protein expression of p53, c-erbB2, and c-met in 42 gastric cancers and correlated these alterations with H. pylori infection, histological subtypes and survival of the patients after curative resection. There were no differences in the incidences of the expression of p53, c-erbB2, and c-met in the tumor tissues according to H. pylori infection. Fifteen p53 mutations in 12 (29%) tumors were identified. More p53 mutations were found in patients with positive serology for H. pylori (43% vs 14%). This difference was not significant, but the small sample size may be insufficient to detect a potential statistical difference. There was neither a H. pylori-associated p53 hot-spot codon mutation nor a H. pylori characteristic mutational pattern of p53. Positive lymph nodes (P = 0.0061) and p53 mutations (P = 0.0035) were the only significant bad prognostic markers for survival after curative resection of the gastric cancers in our study. Our study does not indicate a unique molecular mechanism of p53 mutagenesis through H. pylori infection. The fact that p53 mutations were significantly correlated with poor survival of patients after potentially curative resection of gastric cancer may have clinical implications for multimodal therapies.

In vitro susceptibilities of wild-type or drug-resistant hepatitis B virus to (-)-beta-D-2,6-diaminopurine dioxolane and 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil

Prolonged treatment of chronic hepatitis B virus (HBV) infection with lamivudine ([-]-beta-L-2',3'-dideoxy-3' thiacytidine) or famciclovir may select for viral mutants that are drug resistant due to point mutations in the polymerase gene. Determining whether such HBV mutants are sensitive to new antiviral agents is therefore important. We used a transient transfection system to compare the sensitivities of wild-type HBV and four lamivudine- and/or famciclovir-resistant HBV mutants to adefovir [9-(2-phosphonyl-methoxyethyl)-adenine; PMEA] and the nucleoside analogues (-)-beta-D-2, 6-diaminopurine dioxolane (DAPD) and 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil (L-FMAU). The drug-resistant mutants contained amino acid substitutions in the polymerase protein. We found that the M550I and M550V plus L526M substitutions, which confer lamivudine resistance, did not confer cross-resistance to adefovir or DAPD, but conferred cross-resistance to L-FMAU. The M550V substitution in isolation conferred a similar phenotype to M550I, except that it did not confer significant resistance to L-FMAU. The L526M substitution, which is associated with famciclovir resistance, conferred cross-resistance to L-FMAU but not to adefovir or DAPD. Inhibition of HBV secretion by DAPD, L-FMAU, and adefovir did not always correlate with inhibition of the generation of intracellular HBV replicative intermediates, suggesting that these analogs may preferentially inhibit specific stages of the viral replication cycle.