Decomposition of NO on the alkalized Pt/Al2O3

Catalytic decomposition of NO on platinum catalysts at 873-1,173 K was investigated in the present work. The yield of N2 in the NO decomposition process was significantly increased on the alkalizing Pt/Al2O3 catalyst. The enhancement may be attributed to a trap of additional NO molecules by basic sites ofthe alkalized catalyst. The interstitially adsorbed species (NaOH(NO)Pt) might increase the NO adsorption strength during the catalytic NO reduction process. Pt on the high acidity HY was also active for catalytic decomposition of NO. Nevertheless, its activity decreased at higher temperatures (>1,073 K) because of the distortion of the HY framework. Combined results of XPS (X-ray photoelectron spectra) and TPR (temperature programmed reduction) showed that PtO and PtO2 were the main active species on the alkalized Al2O3 and HY during NO reduction.

Acute hepatitis C virus (HCV) infection in chronic carriers of hepatitis B virus (HBV): the impact of underlying active HBV replication on persistence of HCV infection and antibody responses to HCV

BACKGROUND AND AIMS

The aim of this study was to assess whether underlying chronic hepatitis B virus (HBV) infection interferes with persistence of hepatitis C virus (HCV) infection and humoral immune responses to HCV in acute HCV infection.

METHODS

Serial sera from 12 patients with acute HCV infection (group A) and 12 hepatitis B surface antigen (HBsAg) carriers with acute HCV infection (seven anti-hepatitis B e antigen (anti-HBe) positive (group B1) and five hepatitis B e antigen (HBeAg) positive (group B2)) were tested for HCV RNA by polymerase chain reaction, and anti-HCV by third generation enzyme immunoassay and confirmatory assay. Serial serum samples from HBsAg carriers were also tested for HBeAg, anti-HBe, and HBV DNA by hybridisation assay.

RESULTS

Persistent HCV viraemia for more than six months was significantly more frequent in groups A (83%) and B1 (86%) than in group B2 (0%). Anti-HCV was detected in 100% and 86% of group A and group B1 one month after onset while only one group B2 patient was transiently anti-HCV positive 1-2 months after onset. Of the latter, three had anti-core 1 less than two months after onset while no patient responded to other HCV antigens. Overall, of six HBsAg carriers with acute self limiting HCV infection, only one had transient anti-HCV and three had transient anti-core 1. HBV DNA became undetectable transiently in four and persistently in one group B2 patient.

CONCLUSION

The presence of active HBV replication can inhibit the persistence of HCV infection and antibody responses to HCV. Acute HCV infection in HBsAg carriers with active HBV replication usually presents transient HCV viraemia with poor antibody responses to HCV.

Reactivation of hepatitis C virus superinfection in a patient seropositive for hepatitis B e antigen

During the course of chronic hepatitis B virus (HBV) infection, a patient seropositive for hepatitis B e antigen experienced four episodes of acute hepatic necroinflammation. Serum HBV-DNA concentration elevated immediately before the first and third exacerbations, whereas serum hepatitis C virus (HCV) RNA was detected during the second and fourth exacerbations. The nucleotide sequences of HCV hypervariable region derived from samples of the two exacerbations were identical. Interestingly, "de novo" seroconversion of anti-HCV antibody (Abbott HCV EIA 3.0) followed by reversion occurred in both the second and fourth exacerbations with low sample/cutoff ratios. Immunoblot analysis using a line-immunoassay (Inno-LIA HCV Ab III) revealed a single positive band (C1) developing after the second exacerbation. These data indicate that the second exacerbation in this patient was caused by newly acquired acute HCV superinfection, whereas the fourth exacerbation was likely due to reactivation of the previous HCV infection. Recognition of such a case suggests that the presence of de novo seroconversion of anti-HCV may indicate either reactivation or acute superinfection of HCV in a patient seropositive for hepatitis B e antigen.

Identification of a hepatic factor capable of supporting hepatitis C virus replication in a nonpermissive cell line

Although hepatitis C virus E2 protein can bind to human cells by interacting with a putative viral receptor, CD81, the interaction alone is not sufficient to establish permissiveness for hepatitis C virus infection. Using an Epstein-Barr virus-based extrachromosomal replication system, we have screened through a human liver cDNA library and successfully identified a cDNA capable of supporting hepatitis C virus replication in an otherwise nonpermissive cell line. This cDNA encodes a protein exhibiting homology to a group of proteins derived from various evolutionarily distant species, including Oryza sativa submergence-induced protein 2A. The mRNAs encoding this factor are heterogeneous at the 5' ends and are ubiquitously expressed in multiple tissues, albeit in a very small amount. The longest mRNA contains an in-frame and upstream initiation codon and codes for a larger protein. This 5'-extended form of mRNA was detected in hepatocellular carcinoma, but not in normal liver tissue. Immunofluorescence analysis demonstrated that the hepatic factor was distributed evenly in cells, but occasionally formed aggregations in the peri- or intranuclear areas. In summary, we have identified a hepatic factor capable of supporting hepatitis C virus replication in an otherwise nonpermissive cell line. This factor belongs to a previously uncharacterized protein family. The physiological function of this protein awaits further study.

Epidemiological characteristics, risk factors, and clinical manifestations of acute non-A-E hepatitis

A substantial proportion of acute non-A, non-B hepatitis was of unknown etiology and was termed non-A-E hepatitis. Analysis of the clinical features is needed while attempting to identify the causative agent(s). In this study, the clinical and biochemical features of 53 patients who were admitted to hospital with acute non-A-E hepatitis were compared with a cohort of patients with acute hepatitis C (n = 70) and E (n = 5). In acute non-A-E hepatitis, the sex ratio was 34:19, and ages ranged from 21 to 76 years (median 49). Biochemical tests [median (range)] revealed albumin 3.6 (2.2-4.4) g/dl, AST 714 (193-2311) U/l, ALT 896 (310-3,000) U/l, bilirubin 11.2 (0.9-36.3) mg/dl, and prothrombin time > 1.1 (0-11.5) seconds. No patients reported parenteral exposures or household contact. Forty-five percent had severe hepatitis (i.e., albumin < 3 g/dl, bilirubin > 15 mg/dl or prothrombin time > 3 sec), including 3% with fulminant hepatitis. Chronic evolution was noted in 7%. These features were similar to those of hepatitis C or E, except for a significantly high frequency of parenteral exposures (20%), household contact (16%), and chronicity (70%) in hepatitis C. In conclusion, there is no obvious parenteral risk factor identified in acute non-A-E hepatitis. Clinical severity is similar to that of hepatitis C at least in hospitalized patients, but the rate of chronic evolution is much lower.

Characterization of neutralizing antibodies and identification of neutralizing epitope mimics on the Clostridium botulinum neurotoxin type A

Clostridium botulinum neurotoxin type A (BTx-A) is known to inhibit the release of acetylcholine at the neuromuscular junctions and synapses and to cause neuroparalysis and death. In this study, we have identified two monoclonal antibodies, BT57-1 and BT150-3, which protect ICR mice against lethal doses of BTx-A challenge. The neutralizing activities for BT57-1 and BT150-3 were 10(3) and 10(4) times the 50% lethal dose, respectively. Using immunoblotting analysis, BT57-1 was recognized as a light chain and BT150-3 was recognized as a heavy chain of BTx-A. Also, applying the phage display method, we investigated the antibodies' neutralizing B-cell epitopes. These immunopositive phage clones displayed consensus motifs, Asp-Pro-Leu for BT57-1 and Cys-X-Asp-Cys for BT150. The synthetic peptide P4M (KGTFDPLQEPRT) corresponded to the phage-displayed peptide selected by BT57-1 and was able to bind the antibodies specifically. This peptide was also shown by competitive inhibition assay to be able to inhibit phage clone binding to BT57-1. Aspartic acid (D(5)) in P4M was crucial to the binding of P4M to BT57-1, since its binding activity dramatically decreased when it was changed to lysine (K(5)). Finally, immunizing mice with the selected phage clones elicited a specific humoral response against BTx-A. These results suggest that phage-displayed random-peptide libraries are useful in identifying the neutralizing epitopes of monoclonal antibodies. In the future, the identification of the neutralizing epitopes of BTx-A may provide important information for the identification of the BTx-A receptor and the design of a BTx-A vaccine.

Effective relief of obstructive jaundice in a patient with nonresectable icteric-type hepatocellular carcinoma by external beam radiation therapy: case report

We report on a 62-year-old woman with nonresectable icteric-type hepatocellular carcinoma who developed obstructive jaundice due to tumor thrombi in the common hepatic duct. External beam radiation therapy with total dose of 38 Gy was given in 10 fractions within 4 weeks. The serum bilirubin level progressively decreased from 30.0 to 1.7 mg/dl with a concomitant reduction of tumor size in the 2 months following radiotherapy. Serum alpha-fetoprotein level decreased from greater than 10,000 to 6540 ng/ml after radiotherapy but increased again due to new growth of tumors. The patient was subsequently treated by transcatheter arterial chemoembolization and was still alive 8 months after the diagnosis of nonresectable icteric-type hepatocellular carcinoma. This result suggests that external beam radiation therapy may be beneficial in some patients with nonresectable icteric-type hepatocellular carcinoma. When combined with other conventional therapies, radiation therapy may play an important role in the treatment of hepatocellular carcinoma.

Identification and characterization of a prevalent hepatitis B virus X protein mutant in Taiwanese patients with hepatocellular carcinoma

The aim of this study was to investigate whether there was a particular hepatitis B virus (HBV) X protein (HBx) mutant associated with Taiwanese patients with hepatocellular carcinoma (HCC). Initially, the entire coding region of HBx gene from the serum samples of 14 Taiwanese patients were sequenced. A novel mutant, HBx-A31, was preferentially found in patients with HCC. Sera from 67 patients with HCC and 100 patients with chronic hepatitis B were thus subjected for codon 31 analysis using a dual amplification created restriction site method. HBx-A31 was detected more frequently in patients with HCC (52% versus 12%; P<0.001) and in patients with liver cirrhosis (44% versus 6%; P<0.001). Site directed mutagenesis experiment revealed that HBx-A31 was less effective in transactivating HBV enhancer I-X promoter complex, less efficient in supporting HBV replication, and less potent in enhancing TNF-alpha induced increment of CPP32/caspase 3 activities in HepG2 cells. In conclusion, a prevalent HBx mutant was identified in Taiwanese patients with hepatocellular carcinoma. Development of this mutant might represent a strategy of the virus to escape immune surveillance and thus contribute to the process of multiple-step hepatocarcinogenesis.

Impact of acute hepatitis B virus superinfection on chronic hepatitis C virus infection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) dual infection is not uncommon, but the impact of acute HBV superinfection in patients with chronic HCV infection is still unknown. Two patients with well documented chronic HCV infection were hospitalized for acute hepatitis, which was serologically confirmed to be acute HBV superinfection. One patient who was seropositive for both HBV-DNA and HCV-RNA upon admission died of hepatic failure. The other became seronegative for HCV-RNA and recovered with alanine aminotransferase normalization, seroclearance of HBsAg, and antibodies to HCV. These findings confirm that acute superinfection in patients with chronic hepatitis may increase the risk for severe hepatitis, and suggest that HBV as the newcomer may suppress the pre-existing HCV. Together with the earlier observation that acute HCV superinfection suppresses pre-existing HBV, it seems that the timing or sequence of infection is a factor influencing the outcome of viral interactions.

Prednisolone priming enhances Th1 response and efficacy of subsequent lamivudine therapy in patients with chronic hepatitis B

Asian lamivudine trial has shown that hepatitis B e antigen (HBeAg) seroconversion rate during 1 year of lamivudine therapy was only 16% but was 64% in the subgroup of patients with a pretherapy serum alanine transaminase (ALT) level over 5 times the upper limit of normal (ULN). To test whether ALT rebound following corticosteroid priming enhances response to lamivudine therapy, a pilot study was conducted in 30 patients with ALT levels less than 5x ULN (43-169; N < 36 U/L). They received 30 mg of prednisolone daily for 3 weeks, 15 mg daily for 1 week, no treatment for 2 weeks, and then 150 mg of lamivudine daily for 9 months. Complete response (CR) was defined as ALT normalization with HBV-DNA seroclearance and HBeAg seroconversion. Peripheral blood mononuclear cell proliferation and cytokine secretion in response to recombinant HBV core antigen were serially assayed in 7 patients during priming and after withdrawal of prednisolone. Clinical rebound with an ALT over 5x ULN was observed in 20 patients (67%). Of these 20, 12 (60%) showed CR as compared with 1 (10%) of the 10 patients without significant ALT rebound (P <.002). The HBeAg seroconversion sustained in 70% of the patients 3 to 6 months after the end of lamivudine therapy. Immunological assays revealed that the responders showed Th1 dominant response and higher stimulation index to prednisolone priming. No serious side effect was encountered. These results suggest that corticosteroid priming induced immune/ALT rebound greatly enhances response to lamivudine therapy in chronic hepatitis B. Confirmation by randomized controlled trial is needed.

Aberrant transcripts of the cyclin-dependent kinase-associated protein phosphatase in hepatocellular carcinoma

The cyclin-dependent kinase (Cdk)-associated protein phosphatase (KAP) is a human dual specificity protein phosphatase that dephosphorylates Cdk2 on threonine 160 in a cyclin-dependent manner. To investigate whether mutations of this enzyme occur in hepatocellular carcinoma (HCC), KAP mRNA was analyzed by reverse transcription-PCR (RT-PCR), followed by cloning and sequencing. Eight of 14 biopsy tissues obtained from advanced HCC, 6 of 13 surgically removed HCC tissues, and 2 of the adjacent noncancerous tissues contained aberrant KAP transcripts. Using the yeast two-hybrid system, five of seven representative KAP mutants were shown to be defective in interacting with Cdk2. These data suggest a possible role of KAP mutations in multiple-step hepatocarcinogenesis.

Clearance of the original hepatitis B virus YMDD-motif mutants with emergence of distinct lamivudine-resistant mutants during prolonged lamivudine therapy

Tyrosine-methionine-aspartate-aspartate (YMDD)-motif mutants may emerge and elicit immune clearance during prolonged lamivudine treatment. The aim of this study was to investigate the virological events following development of the original mutants. Twenty-three patients who developed YMDD-motif mutants during the Asian lamivudine trial were included. Serial serum samples from these patients were subjected to sequence analysis to identify new mutants. Site-directed mutagenesis experiments were performed to investigate whether the new mutations were responsible for lamivudine resistance. Of the 23 patients included, 13 harbored either one or a mixture of the two common YMDD-motif mutants (methionine 552-to-isoleucine [M552I] and leucine 528-to-methionine/methionine 552-to-valine [L528M/M552V]) throughout the course, whereas in the remaining 10 patients, distinct mutants became dominant over the original mutants to cause continuing chronic hepatitis. Of them, 3 developed an alanine 529-to-threonine (A529T) mutant, 6 developed a leucine 528-to-methionine/methionine 552-to-isoleucine (L528M/M552I) mutant, and 1 developed these two mutants sequentially. Site-directed mutagenesis experiments confirmed that the aforementioned mutations were responsible for the resistance to lamivudine in vitro. The nucleotide substitution in the A529T mutant concomitantly generated a stop codon at the surface gene, leading to impaired secretion of HBsAg. Strikingly, the replication of this mutant was lamivudine dependent. These results suggested that distinct lamivudine-resistant mutants could emerge and replace the original YMDD-motif mutants as the cause of continuing chronic hepatitis during prolonged lamivudine therapy.

Olone modulates the therapeutic effect of interferon to eliminate preferentially the hepatitis B virus precore stop mutant

BACKGROUND/AIMS

The aim of this study was to understand the changes in the proportion of hepatitis B virus precore stop mutant during the course of prednisolone primed interferon (IFN) therapy.

METHODS

Three groups of patients were included: patients receiving prednisolone-primed IFN treatment (Group I, n=31), IFN treatment only (Group II, n=29), and placebo (Group III, n=25). The proportion of precore stop mutant was measured by a quantitative amplification-created restriction site method.

RESULTS

Distinct patterns of the progression of the proportion of mutant were found among these three groups. A steady increase in the proportion of mutant was observed only in Group III patients. In Group II patients, the presence of a higher percentage of mutant (> 25%) immediately before IFN treatment was predictive for the subsequent clearance of hepatitis B e antigen (HBeAg) (p<0.01), but not for complete anti-viral response (p>0.05). Prednisolone pretreatment resulted in an increase in the proportion of mutant in patients with initially low percentages (< or = 25%) of mutant. During the period of IFN treatment, both the relative and absolute amount of the precore stop mutant decreased significantly in Group I patients who cleared HBeAg. The presence of such a decrease in this group of patients was predictive for both HBeAg clearance and complete anti-viral response.

CONCLUSIONS

Our data suggest that prednisolone serves as a modulator to enhance elimination of precore stop mutant by IFN, which advocates the benefit of corticosteroid pretreatment in an area where the precore mutants are prevalent.

Genetic alternations of p73 are infrequent but may occur in early stage hepatocellular carcinoma

p73, a structural homologue of the tumor suppressor gene, p53, has recently been identified and mapped to chromosome 1p36, where genomic loss of heterozygosity (LOH) often occurs in human hepatocellular carcinoma (HCC). To determine whether p73 is involved in the development of HCC and whether there is an inverse correlation between the mutations of p73 and p53, we examined 22 paired tumors/noncancerous liver tissues for allelic expression, LOH and mutation of p73 and for mutation of p53. p73 was biallelically expressed in noncancerous liver tissues and in 7 out of the 8 informative tumors. One tumor tissue expressed only a single allele. LOH of p73 was found in 2 out of the 11 (18%) informative cases. A tumor-specific five-nucleotide deletion mutation causing a reading frameshift/early truncation of p73 DNA-binding domain was found, in which case no concomitant mutation in the DNA-binding domain of p53 was identified. Nine out of the 22 cases (41%) contained tumor-specific mutations in the DNA-binding domain of p53. Two of the three cases with p73 genetic alternations had a tumor size of less than 2 centimeters. These results suggest that p73 is a biallelically expressed gene in the liver and that allelic loss and mutation of p73 is infrequent and may occur early in HCC. p73 is unlikely to be the putative tumor suppressor gene located at chromosome 1p36 in HCC.

Activation of nuclear factor kappaB in hepatitis C virus infection: implications for pathogenesis and hepatocarcinogenesis

The hepatitis C virus (HCV) core protein is a multifunctional protein. It may bind to the death domain of tumor necrosis factor receptor 1 (TNFR1) and to the cytoplasmic tail of lymphotoxin-beta receptor, implying that it may be involved in the apoptosis and anti-apoptosis signaling pathways. In vitro studies have been inconclusive regarding its ability to inhibit or enhance TNF-alpha-induced apoptosis. To address this issue, electrophoretic mobility shift assay (EMSA) and immunohistochemical studies were used to show the activation of nuclear factor kappaB (NF-kappaB) in HCV-infected liver tissues and in HCV core-transfected cells. The activation of NF-kappaB was correlated with the apoptosis assays. The results showed that NF-kappaB activation could be shown in HCV-infected livers and HCV core-transfected cells. The data of EMSA correlated with those of immunohistochemical studies, which revealed a higher frequency of NF-kappaB nuclear staining in HCV-infected than in normal livers. NF-kappaB activation conferred resistance to TNF-alpha-induced apoptosis in HCV core-transfected cells. Inhibition of NF-kappaB activation by pyrrolidine dithiocarbamate sensitized them to TNF-alpha-induced apoptosis. These findings suggest that HCV infection may cause anti-apoptosis by activation of NF-kappaB and implicate a mechanism by which HCV may evade the host's immune surveillance leading to viral persistence and possibly to hepatocarcinogenesis.

Amino acid substitutions in codons 9-11 of hepatitis C virus core protein lead to the synthesis of a short core protein product

BACKGROUND

Previous in vitro experiments have indicated that if the ninth codon of the hepatitis C virus (HCV) core gene is mutated from arginine to lysine, a short 16-kDa (P16) instead of a 21-kDa (P21) core protein will be produced. In this study, we aimed to investigate whether similar mutations existed in patients with chronic HCV infection and whether such mutations led to the expression of P16.

METHODS

The core gene was isolated from patients' sera by reverse transcription-polymerase chain reaction and sequenced.

RESULTS

Three of 10 patients with hepatocellular carcinoma were found to have mutant viruses with missense mutations at codons 9-11: arginine-to-glycine mutation at codon 9 (case 1); lysine-to-glutamine mutation at codon 10 (case 5); and lysine-to-asparagine/threonine-to-alanine double mutations at codons 10 and 11 (case 8). Site-directed mutagenesis and in vitro translation experiments revealed that P16 was expressed by all three mutants. Using gel-purified P21 and P16 proteins obtained from transformed Escherichia coli, the serum titres of anti-P21 and anti-P16 were assayed. Unequal titres of anti-P16 and anti-P21 were found in only cases 1, 5 and 8. A rabbit antibody directed against P16 but not P21 was thus generated for immunohistochemical analysis. P16 was detected in the nuclei of hepatocytes in the peri-hepatoma tissue of a single case (case 1).

CONCLUSIONS

These data indicate that missense mutations at codons 9-11 can occur during chronic HCV infection, which results in the expression of P16 core protein.

Enhanced decomposition of NO on the alkalized PdO/Al2O3 catalyst

Experimentally, decomposition of NO on the alkalized Pd/Al2O3 catalyst is remarkably enhanced at 825-1000 K. The enhancement in N2 yield may be due to the additional basic sites on the alkalized catalyst that can trap NO molecules. However, at T > 1000 K, due to the fact that the absorbed oxygen in subsurface or bulk of Pd was involved in the formation and desorption of oxygen molecules, yield of oxygen was enhanced.

Age, gender, and local geographic variations of viral etiology of hepatocellular carcinoma in a hyperendemic area for hepatitis B virus infection

BACKGROUND

There are etiologic variations of hepatocellular carcinoma (HCC) in different geographic areas. Taiwan is a hyperendemic area for hepatitis B virus (HBV) infection. Hepatitis C virus (HCV) infection also plays an important role in HCC development in Taiwan. Identification of local HCV-endemic areas is important to keep HCV from spreading. This study investigated the etiologic variations of HCC in different geographic areas of Taiwan.

METHODS

The authors evaluated the hepatitis B surface antigen (HBsAg) and antibodies to HCV (anti-HCV) status of 284 patients (232 male, 52 female) with HCC. They also evaluated the gender ratio and mean age of these patients.

RESULTS

The mean age of HBsAg positive patients was significantly lower than the mean age of HBsAg negative patients (52.6 +/- 12.3 vs. 61.3 +/- 11.2 years) (P < 0.05). The male-to-female ratio was 4.5:1 for all HCC patients, 7:1 for HBsAg positive HCC patients, and 2.8:1 for anti-HCV positive HCC patients. In Chaiyi County in southern Taiwan, the prevalence of anti-HCV in male HCC patients was 52%, significantly greater than that of Taiwan as a whole (27.6%) (P = 0.07). However, the prevalence of anti-HCV in male HCC patients in Taipei County in northern Taiwan was 8.7%, significantly less than that of Taiwan as a whole (P = 0.043). Of a total of 65 Chiayi-based HCC patients, 55.4% were anti-HCV positive and 46.2% were HBsAg positive. In the Chiayi area, results of multiple logistic regression showed that the HCC patients who were age 60 years or older or who were living in the city area both had highly HCV-related disease.

CONCLUSIONS

The mean age of patients with HBV-related HCC was significantly lower than that of patients with non-HBV-related HCC. The male-to-female ratio for patients with HBV-related HCC was significantly higher than that of patients with HCV-related HCC. The authors identified an area of Taiwan in which HCV-related HCC was prevalent.

Replication of hepatitis C virus in ascitic mononuclear cells with development of distinct viral quasispecies

To investigate whether distinct compositions of viral quasispecies developed in the ascitic fluid of patients with late-stage chronic hepatitis C virus (HCV) infection, samples of various origins, including ascitic fluid and ascitic mononuclear cells (AMCs), were analyzed by the method of single-strand conformation polymorphism (SSCP). Subsequently, the major species were isolated, sequenced, and subjected to phylogenetic analysis. Of 42 patients analyzed, HCV-RNA was detectable in the AMCs of 25 patients. SSCP analysis indicated that the compositions of viral quasispecies among samples of different origins were markedly different in this group of patients. Phylogenetic analysis revealed that the ascitic-fluid-derived clones were most closely related to the AMC-derived clones. Minus-strand HCV-RNA was detectable in 5 of them. Our data suggest that HCV can replicate in the AMCs of patients with late-stage chronic HCV, which results in the development of distinct viral quasispecies.

Age, gender, and local geographic variations of viral etiology of hepatocellular carcinoma in a hyperendemic area for hepatitis B virus infection

BACKGROUND

There are etiologic variations of hepatocellular carcinoma (HCC) in different geographic areas. Taiwan is a hyperendemic area for hepatitis B virus (HBV) infection. Hepatitis C virus (HCV) infection also plays an important role in HCC development in Taiwan. Identification of local HCV-endemic areas is important to keep HCV from spreading. This study investigated the etiologic variations of HCC in different geographic areas of Taiwan.

METHODS

The authors evaluated the hepatitis B surface antigen (HBsAg) and antibodies to HCV (anti-HCV) status of 284 patients (232 male, 52 female) with HCC. They also evaluated the gender ratio and mean age of these patients.

RESULTS

The mean age of HBsAg positive patients was significantly lower than the mean age of HBsAg negative patients (52.6 +/- 12.3 vs. 61.3 +/- 11.2 years) (P < 0.05). The male-to-female ratio was 4.5:1 for all HCC patients, 7:1 for HBsAg positive HCC patients, and 2.8:1 for anti-HCV positive HCC patients. In Chaiyi County in southern Taiwan, the prevalence of anti-HCV in male HCC patients was 52%, significantly greater than that of Taiwan as a whole (27.6%) (P = 0.07). However, the prevalence of anti-HCV in male HCC patients in Taipei County in northern Taiwan was 8.7%, significantly less than that of Taiwan as a whole (P = 0.043). Of a total of 65 Chiayi-based HCC patients, 55.4% were anti-HCV positive and 46.2% were HBsAg positive. In the Chiayi area, results of multiple logistic regression showed that the HCC patients who were age 60 years or older or who were living in the city area both had highly HCV-related disease.

CONCLUSIONS

The mean age of patients with HBV-related HCC was significantly lower than that of patients with non-HBV-related HCC. The male-to-female ratio for patients with HBV-related HCC was significantly higher than that of patients with HCV-related HCC. The authors identified an area of Taiwan in which HCV-related HCC was prevalent.

Fulminant hepatic failure in acute hepatitis C: increased risk in chronic carriers of hepatitis B virus

BACKGROUND/AIMS

The role of hepatitis C virus (HCV) in fulminant hepatitis remains controversial. This study was conducted to investigate the risk of fulminant hepatitis C in relation to HCV genotypes and concurrent infection of other viruses.

PATIENTS

109 HCV RNA positive patients from 334 consecutive cases hospitalised to a medical centre in northern Taiwan for overt acute viral hepatitis were prospectively evaluated.

METHODS

HCV RNA was detected by a combined reverse transcription-polymerase chain reaction assay. HCV genotypes were analysed using a genotype specific probe based assay in the 5' untranslated region.

RESULTS

39 patients tested positive for hepatitis B surface antigen but negative for IgM antibody to hepatitis B core antigen, indicating concurrent chronic hepatitis B virus (HBV) infection. Twelve patients were hepatitis G virus (HGV) RNA positive. Genotyping of HCV disclosed 1b in 93, 1b mixed with 2a/2c or 1b mixed with 2b in 11, and not classified in five. Serum titres of HCV RNA were <10(5) copies/ml in 77, 10(5)-10(7) copies/ml in 25, and >10(7) copies/ml in seven. Eleven patients (10.1%) had fulminant hepatitis as a complication. Development of fulminant hepatitis did not correlate with age and gender of the patients, concurrent HGV infection, HCV genotypes, or serum titre of HCV RNA. However, the incidence (95% confidence interval) of fulminant hepatitis in patients with underlying chronic HBV infection was 23. 1% (9.9 to 36.3%), which is significantly higher than in those without (2.9% (-1.0 to 6.8%)). In 39 patients with concurrent chronic HBV infection, the clinical and virological characteristics showed no significant difference between those with fulminant hepatitis and those without.

CONCLUSIONS

Acute hepatitis C in patients with concurrent chronic HBV infection is associated with a substantial risk of fulminant hepatitis.

Case report: spontaneous peritonitis caused by Candida albicans

We report a 40-year-old man with decompensated alcoholic liver cirrhosis, who developed spontaneous peritonitis caused by Candida albicans after complete recovery from a recent episode of acute pancreatitis. The patient was successfully treated with amphotericin B. A search of the literature showed that this is the fourth reported case of spontaneous peritonitis caused by Candida albicans.

Acute exacerbation and hepatitis B virus clearance after emergence of YMDD motif mutation during lamivudine therapy

Lamivudine is a potent inhibitor of hepatitis B virus (HBV) replication, but its long-term use may be associated with HBV tyrosine-methionine-aspartate-aspartate (YMDD) motif mutation. To examine the clinical features and course after emergence of YMDD mutants, 55 patients who received lamivudine therapy over 104 weeks at our unit were assayed for YMDD mutation(s). Thirty-two of them were found to have the YMDD mutation. They continued lamivudine therapy and were followed up weekly or biweekly if clinically indicated. Thirty (93.7%) of them showed elevation of alanine transaminase (ALT), and 13 (40.6%) experienced acute exacerbation at 4 to 94 weeks (median, 24 weeks) after emergence of the YMDD mutant. The incidence of exacerbation is much higher than 4.3% in patients without the YMDD mutation (P =.003). Compared with patients without exacerbation, patients with exacerbation had a significantly higher serum HBV-DNA level after emergence of the YMDD mutant (P <.005). Before exacerbation, serum HBV-DNA level was rising to its peak, followed by the peaking of ALT (247-2,010 U/L) 1 to 4 weeks later. Three patients developed hepatic decompensation, but then in association with hepatitis B e antigen (HBeAg) seroconversion, recovered. Of the 12 evaluable patients, 8 (75%) showed HBeAg seroconversion, and 3 showed mutant clearance within 1 to 5 months after exacerbation. In contrast, none of the patients without exacerbation showed HBeAg seroconversion (P <.001). These results indicate that acute exacerbations may occur after emergence of the YMDD mutation. The incidence, clinicopathological features, and subsequent course, and possibly the underlying immune mechanisms, are similar to those of wild-type HBV chronic infection. Because severe hepatitis may occur, patients should be followed carefully once the YMDD mutant emerges.

High prevalence of TT virus infection in healthy children and adults and in patients with liver disease in Taiwan

A newly identified DNA virus, named TT virus (TTV), was found to be related to transfusion-associated hepatitis. We conducted the following experiments to evaluate its pathogenic role in liver disease and potential modes of transmission. We used PCR to detect TTV DNA in serum. The rates of TTV viremia in 13 patients with idiopathic acute hepatitis, 14 patients with idiopathic fulminant hepatitis, 22 patients with chronic hepatitis, and 19 patients with cirrhosis of the liver were 46, 64, 55, and 63%, respectively, and were not significantly different from those in 50 healthy control subjects (53%). PCR products derived from seven patients with liver disease and three healthy controls were cloned and then subjected to phylogenetic analyses, which failed to link a virulent strain of TTV to severe liver disease. TTV infection was further assessed in an additional 148 subjects with normal liver biochemical tests, including 30 newborns (sera collected from the umbilical cord), 23 infants, 16 preschool children, 21 individuals of an age prior to that of sexual experience (aged 6 to 15 years), 15 young adults (aged under 30 years), and 43 individuals older than 30 years. The rates of TTV viremia were 0, 17, 25, 33, 47, and 54%, respectively. These findings suggest that TTV is transmitted mainly via nonparenteral daily contact and frequently occurs very early in life and that TTV infection does not have a significant effect on liver disease.

Etiology of sporadic acute viral hepatitis in Taiwan: the role of hepatitis C virus, hepatitis E virus and GB virus-C/hepatitis G virus in an endemic area of hepatitis A and B

The etiology of sporadic acute hepatitis was studied in 334 consecutive patients from Taiwan (237 men and 97 women, aged 16-81 years), with emphasis on the role of hepatitis C virus (HCV), hepatitis E virus (HEV), and GB virus-C/hepatitis G virus (GBV-C/HGV) in acute non-A, non-B (NANB) hepatitis and in HBsAg carriers with superimposed acute hepatitis. According to the conventional diagnostic criteria, there were 12 cases (3.6%) of acute hepatitis A, 17 cases (5.1%) of acute hepatitis B, 128 cases (38.3%) of acute NANB hepatitis, and 177 cases (53.0%) of acute hepatitis in HBsAg carriers (those who were HBsAg positive but IgM anti-HBc negative). Among 128 cases of acute NANB hepatitis, 70 (54.7%) had acute hepatitis C (HCV RNA positive), 5 (3.9%) had acute hepatitis E (IgM anti-HEV positive), and the other 53 (41.4%) were presumably acute hepatitis non-A-E. The prevalence of acute hepatitis A, B, E, and non-A-E showed no significant sex difference, whereas acute hepatitis C was significantly more prevalent in females. The prevalence of acute hepatitis A and B decreased and that of acute hepatitis C increased significantly with increasing age. In contrast, acute hepatitis E and non-A-E showed no significant age predominance. Of 177 HBsAg carriers with acute hepatitis, 64 (36.1%) demonstrated non-B hepatotropic virus superinfection, with HCV being the most common (60.9%), followed by hepatitis D, E, and A viruses, and the other 55 (31.1%) and 58 (32.8%) were presumed to have acute exacerbation of chronic hepatitis B or superimposed acute hepatitis non-A-E, respectively. Serum GBV-C/HGV RNA was detected in 3-4% of acute hepatitis non-A-E cases, suggesting its limited role in these cases.

Prevalence and significance of thyroid autoantibodies in patients with chronic hepatitis C virus infection: a prospective controlled study

OBJECTIVE

To clarify controversies on the prevalence and clinical significance of thyroid autoimmunity in hepatitis C virus (HCV) infection.

DESIGN

A prospective controlled and follow-up study.

PATIENTS AND MEASUREMENTS

Serum thyroid microsomal antibody (TMA) and thyroid stimulating hormone were assayed and compared in a consecutive, unselected series of 130 patients with chronic HCV infection, 130 sex/age (+/- 2 years)-matched patients with chronic hepatitis B virus (HBV) infection and 260 matched normal controls.

RESULTS

The prevalence of thyroid autoantibodies in male patients with chronic HCV was < 2%. The prevalence of TMA (< 1:400) in female patients with chronic HCV infection was significantly higher than that of HBV controls (22.1 vs. 1.6%; P < 0.001), and higher but not significant compared with normal controls (13.5%). However, the trend of increasing prevalence with age in normal controls was not observed in HCV patients. TMA seropositive female HCV patients were not different from seronegative counterparts in age, duration of infection, HLA haplotype, associated autoantibodies and liver histology but had a significantly higher prevalence of genotype 1b/2b mixed infection (P < 0.01) and anti-GOR (P < 0.05). Of the 23 HCV patients seropositive for thyroid autoantibodies, seven had Hashimoto's thyroiditis, two had Graves' disease and three had received subtotal thyroidectomy. During follow-up, four of 15 female patients showed a 14-16-fold increase in TMA titre and one developed hyperthyroidism. Patients with thyroid autoantibodies did not show a propensity to develop thyroid dysfunction during interferon therapy.

CONCLUSIONS

These results suggest a weak association between HCV and thyroid autoimmunity in females. As in the ordinary population with thyroid autoantibodies, they should be evaluated for thyroid status and be followed-up if thyroid autoimmunity is evident. However, seropositivity of thyroid autoantibodies is not a contraindication to interferon therapy.

Risk of transient hyperammonemic encephalopathy in cancer patients who received continuous infusion of 5-fluorouracil with the complication of dehydration and infection

From 1986 to 1998, 29 cancer patients who had 32 episodes of transient hyperammonemic encephalopathy related to continuous infusion of 5-fluorouracil (5-FU) were identified. None of the patients had decompensated liver disease. Onset of hyperammonemic encephalopathy varied from 0.5 to 5 days (mean: 2.6 +/- 1.3 days) after the initiation of chemotherapy. Plasma ammonium level ranged from 248 to 2387 microg% (mean: 626 +/- 431 microg%). Among the 32 episodes, 26 (81%) had various degrees of azotemia, 18 (56%) occurred during bacterial infections and 14 (44%) without infection occurred during periods of dehydration. Higher plasma ammonium levels and more rapid onset of hyperammonemia were seen in 18 patients with bacterial infections (p=0.003 and 0.0006, respectively) and in nine patients receiving high daily doses (2600 or 1800 mg/m2) of 5-FU (p=0.0001 and < 0.0001, respectively). In 25 out of 32 episodes (78%), plasma ammonium levels and mental status returned to normal within 2 days after adequate management. In conclusion, hyperammonemic encephalopathy can occur in patients receiving continuous infusion of 5-FU. Azotemia, body fluid insufficiency and bacterial infections were frequently found in these patients. It is therefore important to recognize this condition in patients receiving continuous infusion of 5-FU.

Viral superinfection in previously unrecognized chronic carriers of hepatitis B virus with superimposed acute fulminant versus nonfulminant hepatitis

The role of viral superinfection in hepatitis B surface antigen carriers with superimposed fulminant (n = 60) versus nonfulminant (n = 90) acute hepatitis was studied. The frequency of hepatitis A virus (HAV) (0 versus 2.2%), HCV (18.3 versus 21.1%), HDV (15.0 versus 7.8%), and HEV (1.7 versus 4.4%) infection showed no significant difference, while simultaneous HCV and HDV infection was significantly more prevalent in the former (8.3 versus 0%). Only 3. 6% of fulminant cases and 3.3% of nonfulminant controls were HGV RNA positive.

Study of Dengue virus infection in SCID mice engrafted with human K562 cells

Here we report that severe combined immunodeficient (SCID) mice engrafted with human K562 cells (K562-SCID mice) can be used as an animal model to study dengue virus (DEN) infection. After intratumor injection into K562 cell masses of PL046, a Taiwanese DEN-2 human isolate, the K562-SCID mice showed neurological signs of paralysis and died at approximately 2 weeks postinfection. In addition to being detected in the tumor masses, high virus titers were detected in the peripheral blood and the brain tissues, indicating that DEN had replicated in the infected K562-SCID mice. In contrast, the SCID mice were resistant to DEN infection and the mock-infected K562-SCID mice survived for over 3 months. These data illustrate that DEN infection contributed directly to the deaths of the infected K562-SCID mice. Other serotypes of DEN were also used to infect the K562-SCID mice, and the mortality rates of the infected mice varied with different challenge strains, suggesting the existence of diverse degrees of virulence among DENs. To determine whether a neutralizing antibody against DEN in vitro was also protective in vivo, the K562-SCID mice were challenged with DEN-2 and received antibody administration at the same time or 1 day earlier. Our results revealed that the antibody-treated mice exhibited a reduction in mortality and a delay of paralysis onset after DEN infection. In contrast to K562-SCID, the persistently DEN-infected K562 cells generated in vitro invariably failed to be implanted in the mice. It seems that in the early stage of implantation, a gamma interferon activated, nitric oxide-mediated anti-DEN effect might play a role in the innate immunity against DEN-infected cells. The system described herein offers an opportunity to explore DEN replication in vivo and to test various antiviral protocols in infected hosts.

Hepatitis C virus variants circumventing cytotoxic T lymphocyte activity as a mechanism of chronicity

BACKGROUND & AIMS

High rate of chronicity after acute hepatitis C virus (HCV) infection cannot be explained in the presence of a multispecific cytotoxic T lymphocyte (CTL) response. The aim of this study was to investigate the effect of virus variants on CTL activity in patients in whom chronicity developed.

METHODS

CTL clones specific to a decapeptide epitope derived from hypervariable region 1 were generated from 5 HLA-A2-positive patients with acute hepatitis C by in vitro stimulation with synthetic peptides. The sequential change of this CTL epitope and its influence on the CTL recognition were examined.

RESULTS

Virus variants did not appear in 3 patients with recovery, whereas variants with altered peptide ligands capable of antagonizing CTL activity emerged rapidly in the remaining 2 patients in whom chronicity developed. Importantly, these HLA-A2-restricted, hypervariable region 1-specific CTL clones shared the use of T-cell receptor (TCR) genes AV6 and BV17.

CONCLUSIONS

These data suggest that there is only a narrow T-cell repertoire responding to a single viral peptide/HLA ligand. The emergence of HCV variants with altered peptide ligands as TCR antagonists accompanied by a limited TCR repertoire may provide a mechanism for HCV chronicity.

Emergence of an S gene mutant during thymosin alpha1 therapy in a patient with chronic hepatitis B

The presence of a hepatitis B virus S gene mutant was investigated in a patient being treated with thymosin alpha1. He was seropositive for hepatitis B e antigen throughout therapy but was intermittently seronegative for hepatitis B surface antigen (HBsAg) by an RIA. Sequence analysis revealed an S gene mutant in HBsAg-seronegative serum with two consecutive amino acid substitutions: threonine115-to-isoleucine and threonine116-to-asparagine, whereas no amino acid substitution or deletion was found in the pre-S region. A site-directed mutagenesis experiment confirmed that these mutations were responsible for the failure to detect HBsAg. In summary, an S gene mutant was identified in an HBsAg-seronegative patient. The mutations were located outside the putative "a" determinant. The emergence of an S gene mutant during thymosin alpha1 treatment suggests that enhanced host immunity against HBsAg may play a role in its antiviral activity.

Low-level viremia and intracellular expression of hepatitis B surface antigen (HBsAg) in HBsAg carriers with concurrent hepatitis C virus infection

Assays of hepatitis B virus (HBV) replication and antigen expression in HBV surface antigen (HBsAg) carriers with concurrent hepatitis C or D virus (HCV or HDV) infection revealed that HCV and HDV can suppress HBV replication but that HCV also substantially suppresses HBV surface protein expression. HBsAg carriers with concurrent HCV infection thus have low-level viremia and intracellular HBsAg.

G1 phase dependent nuclear localization of relaxed-circular hepatitis B virus DNA and aphidicolin-induced accumulation of covalently closed circular DNA

During chronic hepatitis B virus (HBV) infection, virus persistence relies on the maintenance of a pool of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. To achieve this, HBV DNA has to be transported from the cytoplasm to the nucleus. By carrying out subcellular fractionation experiment, both of the relaxed-circular (RC) and single-stranded (SS) HBV DNA were found in the cytoplasm whereas only RC form could be detected in the nucleus of a hepatoblastoma cell line (HepG2) stably producing HBV. This fraction of nuclear RC viral DNA was clearly demonstrated in the G1 but not S phase of synchronized HepG2 cells. Conversely, the relative amount of cytoplasmic RC viral DNA in the S phase was larger than that in the G1 phase. Although no cccDNA could be detected in HepG2 cells without synchronization, an increasing amount of cccDNA in the nucleus was demonstrated after prolonged incubation of the cells in aphidicolin. Finally, by undertaking in situ hybridization using a probe specific to plus-strand HBV DNA, nuclear viral DNA was detected predominantly in the G1 phase of HepG2 cells. In summary, the results indicated that only RC but not SS form of HBV DNA was localized to the nuclei of HepG2 cells. The nuclear localization occurred preferentially in the G1 but not S phase and prolonged treatment with aphidicolin resulted in accumulation of nuclear cccDNA.

Efficacy of thymosin alpha1 in patients with chronic hepatitis B: a randomized, controlled trial

Thymosin alpha1 (Talpha) is an immune modifier that has been shown in a pilot study to be effective for chronic hepatitis B; this requires confirmation. Ninety-eight patients with clinicopathologically proven chronic hepatitis B were randomly allocated to 3 groups: 1) group A received a 26-week course of Talpha with a 1.6-mg subcutaneous injection two times a week (T6 group); 2) group B received the same regimen as group A, but Talpha therapy extended for 52 weeks (T12 group); and 3) group C served as a control group and was followed up for 18 months without specific treatment (T0 group). The three groups were comparable in clinicohistological features at entry. The complete virological response rate (clearance of serum hepatitis B virus [HBV] DNA and hepatitis B e antigen [HBeAg]) was higher in group A (40.6%) and group B (26.5%) than in group C (9.4%) (group A vs. group C: P=.004; group B vs. group C: P=.068) when assessed 18 months after entry, although complete response rates among these three groups were similar when first assessed at the end of therapy. There was a trend for complete virological response to increase or accumulate gradually after the end of Talpha therapy. None of the responders lost hepatitis B surface antigen. Blinded histological assessment showed a significant improvement in treated patients, particularly in lobular necroinflammation and scores excluding fibrosis. No significant side effects were observed. These results suggest that a 26-week course of Talpha therapy is effective and safe in patients with chronic hepatitis B.

G1 phase dependent nuclear localization of relaxed-circular hepatitis B virus DNA and aphidicolin-induced accumulation of covalently closed circular DNA

During chronic hepatitis B virus (HBV) infection, virus persistence relies on the maintenance of a pool of covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes. To achieve this, HBV DNA has to be transported from the cytoplasm to the nucleus. By carrying out subcellular fractionation experiment, both of the relaxed-circular (RC) and single-stranded (SS) HBV DNA were found in the cytoplasm whereas only RC form could be detected in the nucleus of a hepatoblastoma cell line (HepG2) stably producing HBV. This fraction of nuclear RC viral DNA was clearly demonstrated in the G1 but not S phase of synchronized HepG2 cells. Conversely, the relative amount of cytoplasmic RC viral DNA in the S phase was larger than that in the G1 phase. Although no cccDNA could be detected in HepG2 cells without synchronization, an increasing amount of cccDNA in the nucleus was demonstrated after prolonged incubation of the cells in aphidicolin. Finally, by undertaking in situ hybridization using a probe specific to plus-strand HBV DNA, nuclear viral DNA was detected predominantly in the G1 phase of HepG2 cells. In summary, the results indicated that only RC but not SS form of HBV DNA was localized to the nuclei of HepG2 cells. The nuclear localization occurred preferentially in the G1 but not S phase and prolonged treatment with aphidicolin resulted in accumulation of nuclear cccDNA.

Clinical and virological course of chronic hepatitis B virus infection with hepatitis C and D virus markers

OBJECTIVE

Hepatitis B, C, and delta virus (HBV, HCV, HDV) share similar transmission routes; thus, dual or triple infections may occur and even persist in the same patient. However, little is known about the presentations and course of chronic HBV infection with HCV and HDV markers, which this study examined.

METHODS

Antibodies against HCV (anti-HCV) and HDV (anti-HDV) were assayed as appropriate in patients with HBV infection. The clinical, pathological, and virological presentations as well as the course of the disease in patients with HBV/HDV/HCV triple infection markers were then reviewed.

RESULTS

A total of 60 patients, 51 men and nine women, age 19-67 yr (mean 45.9+/-1.6 yr) were identified. Of these 60 patients, five (8.3%) were HBeAg positive and 10 (16.7%) cirrhotic at entry, 30 (50%) presented with acute superinfection (HCV or HDV, or both) and the remaining 30 presented with chronic liver disease. On presentation, 16 (53.3%) of the 30 patients with acute superinfection showed hepatic decompensation and eight (26.7%) died. In contrast, only one of the patients with "chronic liver disease" presented with hepatic decompensation. Of the 42 patients followed up for 1-15 (mean, 4.7+/-0.6) yr, 45.2% showed remission and 19% showed HBsAg seroclearance, whereas 12.5% of the 32 noncirrhotics developed cirrhosis and three of the nine cirrhotics became decompensated. At the end of follow-up, 29 patients (69.9%) were still seropositive for HCV-RNA but only nine (22.5%) were seropositive for HDV-RNA and five (12.5%) were seropositive for HBV-DNA.

CONCLUSIONS

These results suggest that infection with HBV, HCV, and HDV triple markers is a severe disease in acute superinfection stage but that the course is relatively benign, slowly progressive, and usually dominated by HCV.

Progression of the proportion of hepatitis B virus precore stop mutant following acute superinfection of hepatitis C

To examine the progression of the proportion of hepatitis B virus (HBV) precore stop mutant (codon 28 of precore sequence; TGG to TAG) in the viral population of patients with dual hepatitis virus (B and C) infection, a series of serum samples obtained from six cases with chronic hepatitis B with acute hepatitis C superinfection were analysed by the method of amplification-created restriction site. At the time of superinfection, all patients included in the study were negative for hepatitis B e antigen and positive for its antibody. During the follow up of 30-90 months, in five of the six patients, three different patterns were observed: (i) the proportion of precore stop mutant increased in the first 20 months after acute hepatitis C virus superinfection and then decreased progressively thereafter (two cases); (ii) the proportion of precore stop mutant decreased progressively after superinfection (two cases); and (iii) no precore stop mutant was found during the course (one case). The remaining patient showed a progressive increase in the proportion of precore stop mutant over a period of 9 months after superinfection. Rather than the progressive increase in the proportion of precore stop mutants during the natural course of chronic HBV infection alone, the results of the present study showed a reverse course of progression following acute hepatitis C virus superinfection. This observation raised the possibility of a preferential or accumulative suppression on precore stop mutant by hepatitis C virus in the later stage of dual infection.

DNA immunization with Japanese encephalitis virus nonstructural protein NS1 elicits protective immunity in mice

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is a zoonotic pathogen that is prevalent in some Southeast Asian countries and causes acute encephalitis in humans. To evaluate the potential application of gene immunization to JEV infection, we characterized the immune responses from mice intramuscularly injected with plasmid DNA encoding JEV glycoproteins, including the precursor membrane (prM) plus envelope (E) proteins and the nonstructural protein NS1. When injected with the plasmid expressing prM plus E, 70% of the immunized mice survived after a lethal JEV challenge, whereas when immunized with the plasmid expressing NS1, 90% of the mice survived after a lethal challenge. As a control, the mice immunized with the DNA vector pcDNA3 showed a low level (40%) of protection, suggesting a nonspecific adjuvant effect of the plasmid DNA. Despite having no detectable neutralizing activity, the NS1 immunization elicited a strong antibody response exhibiting cytolytic activity against JEV-infected cells in a complement-dependent manner. By contrast, immunization with a construct expressing a longer NS1 protein (NS1'), containing an extra 60-amino-acid portion from the N terminus of NS2A, failed to protect mice against a lethal challenge. Biochemical analyses revealed that when individually expressed, NS1 but not NS1' could be readily secreted as a homodimer in large quantity and could also be efficiently expressed on the cell surface. Interestingly, when NS1 and NS1' coexisted in cells, the level of NS1 cell surface expression was much lower than that in cells expressing NS1 alone. These data imply that the presence of partial NS2A might have a negative influence on an NS1-based DNA vaccine. The results herein clearly illustrate that immunization with DNA expressing NS1 alone is sufficient to protect mice against a lethal JEV challenge.

Molecular cloning of a defective hepatitis C virus genome from the ascitic fluid of a patient with hepatocellular carcinoma

A defective hepatitis C virus (HCV) genome in the ascitic fluid of a patient with hepatocellular carcinoma was cloned and sequenced up to the 3' poly(U) stretch. When compared with the published Taiwanese HCV sequence, this defective genome contained deletions of single nucleotides at eight sites, double nucleotides at two sites, triple nucleotides at four sites, quadruple nucleotides at one site and replacement of a short stretch of sequence at one site. For comparison, the corresponding regions containing these mutations were also cloned from a serum sample from this patient. Except for deletions of two triple nucleotides in the hypervariable region, the reading frames of all serum-derived clones were intact. The defective HCV genome encoded a truncated core protein with 90 amino acid residues (the last 20 amino acid residues came from a different reading frame), whereas the serum-derived genome encoded a full-length core protein. When expressed in Huh-7 cells, these two proteins were localized to the nucleus and cytoplasm, respectively. Using specific primer-sets, ascites- and serum-derived genomes were each detected alone in ascitic fluid and serum samples, respectively, whereas both sequences were present in ascitic mononuclear cells. The defective sequence thus constituted the major virus population in the ascitic fluid whereas a putative helper genome coexisted with it inside the ascitic mononuclear cells. This sequence is possibly a defective and interfering genome.

Effect of enforced expression of human bcl-2 on Japanese encephalitis virus-induced apoptosis in cultured cells

Infection by Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, causes acute encephalitis in humans and induces severe cytopathic effects in different types of cultured cells. This study attempted to determine whether apoptosis contributes to virus-induced cell death in a culture system by characterizing JEV lytic infection in baby hamster kidney BHK-21 cells, murine neuroblastoma N18 cells, and human neuronal progenitor NT2 cells. According to our results, the replication of JEV, and not the UV-inactivated virions per se, triggered apoptosis in these cell lines, as evidenced by nuclear condensation, DNA fragmentation ladder, and in situ end labeling of DNA strand breaks with terminal transferase (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay). Different strains of JEV, regardless of whether they are neurovirulent to mice, could induce apoptosis of the infected cells. In addition, enforced expression of the human protooncogene bcl-2 in BHK-21 cells, which did not influence virus production, appeared to delay the process of JEV-induced apoptosis, despite the fact that most infected cells were inevitably killed after prolonged cultures. However, Bcl-2 proteins expressed in N18 cells failed to block JEV-induced apoptosis, although they did prevent Sindbis virus-induced apoptosis from occurring in the same cells. This finding suggests that these two viruses may utilize similar but not identical mechanisms to kill their infected cells. The results presented here thus demonstrate that apoptosis can be a general mechanism for JEV-induced cell death and that enforced bcl-2 expression may be inadequate in protecting all cell types from JEV-induced apoptosis in cell cultures.

Response of patients with dual hepatitis B virus and C virus infection to interferon therapy

Patients with dual infection with hepatitis B virus (HBV) and delta virus (HDV) responded poorly to interferon (IFN) therapy. Little is known about the effect of IFN therapy in patients with HBV and hepatitis C virus (HCV) dual infection. The patients in two randomized controlled trials with chronic HBV infection were retrospectively assayed for HCV markers. The HBV responses to IFN therapy in patients with and without HCV markers were compared. An open trial was conducted in 4 patients who had lost their serum HBV surface antigen (HBsAg) but had continuing HCV viremia and hepatitis. Of the 15 patients seropositive for HCV marker(s), only 1 (6.7%) responded with seroclearance of HBV DNA and HBV e antigen, as compared with 46 (28%) of 164 HCV-negative patients (p = 0.058). Icteric hepatitis developed in 1 patient on emergence of serum HCV RNA in association with seroclearance of HBV DNA. In contrast, good response was demonstrated in 3 of the 4 patients who had lost serum HBsAg before therapy. The results suggest that IFN therapy is not only of limited value in patients with dual infection with HBV and HCV but also has a potential risk of severe hepatitis if the clearance of one virus removes its suppressive effect on and facilitates the emergence of the other. However, patients with continuing HCV hepatitis after termination of the chronic HBsAg carrier state responded well to IFN therapy.

Inhibition of Japanese encephalitis virus infection by nitric oxide: antiviral effect of nitric oxide on RNA virus replication

The antiviral effects of nitric oxide (NO) on Japanese encephalitis virus (JEV), a member of the family Flaviviridae, were investigated in this study. In vitro, inhibition of replication of JEV in gamma interferon-activated RAW 264.7 murine macrophages was correlated to cellular NO production. When cocultured with infected murine neuroblastoma N18 cells, gamma interferon-activated RAW 264.7 cells also efficiently hindered JEV replication in contiguous bystanders, and this anti-JEV effect could be reversed by an NO synthase (NOS) inhibitor, N-monomethyl-L-arginine acetate. In vivo, the mortality rate increased as the NOS activity of JEV-infected mice was inhibited by its competitive inhibitor, N-nitro-L-arginine methyl ester. Moreover, when an organic donor, S-nitro-N-acetylpenicillamine (SNAP), was used, the NO-mediated antiviral effect was also observed in primarily JEV-infected N18, human neuronal NT-2, and BHK-21 cells, as well as in persistently JEV-infected C2-2 cells. These data reaffirm that NO has an effective and broad-spectrum antimicrobial activity against diversified intracellular pathogens. Interestingly, the antiviral effect of NO was not enhanced by treatment of N18 cells with SNAP prior to JEV infection, a measure which has been shown to greatly increase the antiviral effect of NO in infection by vesicular stomatitis virus. From biochemical analysis of the impact of NO on JEV replication in cell culture, NO was found to profoundly inhibit viral RNA synthesis, viral protein accumulation, and virus release from infected cells. The results herein thus suggest that NO may play a crucial role in the innate immunity of the host to restrict the initial stage of JEV infection in the central nervous system.

Quantitative assessment of hepatitis C virus RNA by polymerase chain reaction and a digoxigenin detection system: comparison with branched DNA assay

A method for quantifying hepatitis C virus (HCV) RNA in serum using reverse transcription-polymerase chain reaction (RT-PCR) followed by slot-blot hybridization with a specific, digoxigenin-labeled probe was developed. Using RNA synthesized from cloned HCV cDNA as a standard, serum concentration of HCV RNA above 10 copies/ml can be quantitatively determined. To compare this method with branched DNA (bDNA) assay, 45 serum samples from 26 patients with newly acquired acute hepatitis C (n = 16) or hepatitis C with acute exacerbation (n = 10) were submitted to both assays. HCV RNA in 30 (67%), 12 (27%) and three (6.7%) samples can be quantitatively determined by both, either and none of the two assays, respectively. Using a standardized qualitative HCV RNA detection test (Amplicor HCV test) as a reference, 1 and 0 false positive results were found by bDNA and this assay, respectively. This quantitative assay using RT-PCR and a digoxigenin detection system was comparable to bDNA assay. Since a false positive result was rarely found, this technique can be used as a first line test to screen a large number of samples rapidly and economically.

The degrees of hepatocyte nuclear but not cytoplasmic expression of hepatitis B core antigen reflect the level of viral replication in chronic hepatitis B virus infection

Although immunodetection of hepatitis B core antigen (HBcAg) in the liver has long been recognized as a marker of active hepatitis B virus (HBV) replication, the correlation between the level of viral replication and the degrees of expression of HBcAg in hepatocytes remains to be established. In this study, we examined the semiquantitative relationship between the level of HBV DNA in serum and the degree of expression of HBcAg in the hepatocyte nucleus or cytoplasm in 80 adults with chronic hepatitis B. Expression of HBcAg in hepatocytes was studied by the avidin-biotin immunoperoxidase method, and the results were scored on a scale of 0 to 4, values corresponding to the positivity of 0, 1 to 10, 11 to 25, 26 to 50, and > 50%, respectively, of hepatocytes examined. Serum HBV DNA was tested by a liquid hybridization assay, and the results were scored on a scale of 0 to 5, values corresponding to undetectable levels and levels of < or = 50, 51 to 100, 101 to 150, 151 to 200, and > 200 pg/ml, respectively. The results revealed a highly significant, positive correlation between the level of HBV DNA in serum and the degree of expression of HBcAg in nuclei (Spearman rank correlation coefficient [rs] = 0.653, P < 0.001). The mean scores (95% confidence intervals) of levels of HBV DNA in sera of patients whose levels of expression of HBcAg in nuclei received a score of 0 (n = 33), 1 or 2 (n = 35), and 3 or 4 (n = 12) were 1.3 (1.1 to 1.5), 2.5 (2.1 to 2.9), and 3.9 (3.1 to 4.7), respectively. However, no correlation between the level of HBV DNA in serum and the degree of expression of HBcAg in the cytoplasm was noted (rs = 0.026, P > 0.8). In conclusion, the degree of expression of HBcAg in the hepatocyte nucleus but not the cytoplasm can accurately reflect the level of viral replication in patients with chronic hepatitis B.

Distinct composition of viral quasispecies between ascites and serum samples from patients with late stage chronic hepatitis C

By performing single-strand conformation polymorphism and PCR-cloning followed by sequencing, the amino acid composition of hepatitis C virus hypervariable and variable regions were analyzed in ascites and serum samples from two patients with late stage chronic hepatitis C. In patient-LC, the major ascitic clone was constituted by a minor serum-derived clone, while the major serum derived clone was absent in the ascites. In patient-HCC, the major ascitic clone was defective and genetically different from all the serum-derived clones. In addition, anti-genomic HCV RNA was detected in the ascitic mononuclear cells from patient-LC. These results argued that the peritoneal cavity served as a relatively isolated environment for evolution of distinct composition of viral quasispecies.

Generation and characterization of organ-tropism mutants of Japanese encephalitis virus in vivo and in vitro

Using gamma-ray irradiation, a pair of virulent (RP-9) and attenuated (RP-2ms) variants of Japanese encephalitis virus (JEV) were generated from a Taiwanese isolate, NT109. The two variants differed in plaque morphology, virus adsorption, and growth properties in BHK-21 cells: (i) RP-2ms produced smaller plaques than RP-9; (ii) RP-2ms adsorbed less efficiently to host cells but yielded a higher virus titer (burst size); and (iii) RP-2ms virions were mostly accumulated intracellularly, whereas RP-9 was released extracellularly. In addition, in an in vitro binding assay, the envelope (E) protein of RP-9, but not that of RP-2ms, bound specifically to a cellular protein of 57-kDa derived from BHK-21 cells. When injected into mice intracerebrally, RP-2ms was much less virulent than RP-9, with 50% lethal doses of > 10(7) and 0.4 plaque forming units, respectively. Moreover, when inoculated intraperitoneally, their organ tropism differed in that the main target organ for RP-2ms was liver, whereas that for RP-9 was brain. These results suggest that RP-2ms was less neurovirulent and less neuroinvasive from peripheral routes. Molecular analysis of the virus structural proteins detected only two differences between RP-9 and RP-2ms: one in E protein, Glu-138 in RP-9 and Lys-138 in RP-2ms, and the other in prM, Tyr-43 in RP-9 and His-43 in RP-2ms. Since the N-terminal 92 amino acids of prM are cleaved and not present in mature JEV virions, the single-amino-acid change of the E protein at position 138 may account for the difference between the mutants in the in vitro binding assay. Such mutation in E protein, or perhaps in conjunction with the prM mutation, may be responsible, in part, for the phenotypic differences observed in vitro and in vivo between the two mutants.

A highly attenuated strain of Japanese encephalitis virus induces a protective immune response in mice

A pair of virulent (RP-9) and attenuated (RP-2ms) mutants of Japanese encephalitis virus (JEV) were generated from a Taiwanese isolate NT109. The mutants differed in several aspects in vitro and in vivo. RP-2ms exhibited smaller plaque than RP-9 on BHK-21 cells, and when intracerebrally injected, RP-2ms was much less neurovirulent than RP-9. As peripherally inoculated, RP-2ms lost neuroinvasiveness while RP-9 penetrated blood-brain barrier, replicated in mouse brain, and killed all the mice. Single RP-2ms immunization completely protected C3H and ICR mice from a lethal challenge with RP-9; the sera from such mice contained antibodies against JEV envelope and nonstructural 1 proteins, indicating RP-2ms had replicated in the mice Neutralizing activity against NT109 in such sera was further demonstrated by plaque reduction neutralization test. In addition, significant lymphoproliferation was detected in spleen cells from the RP-2ms-immunized mice, and cytotoxic activity in these cells specific for the MHC-matched, JEV-infected cells, but not mock cells, was also observed. Altogether, these results demonstrate that RP-2ms, a highly attenuated JEV strain, can induce a protective immunity in mice.

Precore mutant of hepatitis B virus prevails in acute and chronic infections in an area in which hepatitis B is endemic

By using an amplification-created restriction site method, the precore TAG mutant of hepatitis B virus was detected in 6 (75%) of 8 acute fulminant hepatitis B patients, 7 (58%) of 12 acute self-limiting hepatitis B patients, 35 (81%) of 43 hepatitis B virus surface antigen carriers with fulminant hepatitis, and 42 (70%) of 60 hepatitis B virus surface antigen carriers with chronic hepatitis. The precore TAG mutant prevails in acute and chronic hepatitis B of various severity in this area where hepatitis B is endemic.

Detection of Helicobacter pylori by polymerase chain reaction assay using gastric biopsy specimens taken for CLOtest

The concordance rate between a rapid urease test (CLOtest) and polymerase chain reaction (PCR) assay for the detection of Helicobacter pylori in gastric biopsy samples was investigated. To avoid the bias produced by patchy distribution of the organism in the stomach, the samples used for these two tests were not obtained from two different sites of the antrum. Instead, the PCR assay was performed with the the same biopsy sample that was taken for the CLOtest. Among 82 biopsy samples included for this study, 56 were positive and 26 were negative by CLOtest. Of the 56 CLOtest-positive samples, 52 (93%) were also positive by PCR assay, and of the 26 CLOtest-negative samples, 20 (78%) were negative by PCR assay. The total concordance rate of these two tests was 87.6%. Of the 4 cases with CLOtest-positive and PCR-negative results, 3 had been treated with long-term H2 blockers. Of the 6 patients with CLOtest-negative and PCR-positive results, 4 suffered from recurrent or poorly healing duodenal ulcers. Interestingly, a significantly lower density of the PCR products was observed during electrophoresis analysis for all the 6 cases, presumably due to a small number of H. pylori in these samples. These results indicated that PCR might be used as a complementary assay for CLOtest. False negative results by CLOtest might occur when only a small amount of H. pylori was present in the samples, which could be detected by subsequent PCR assays using the same biopsy specimens. The clinical significance of such CLOtest-negative and PCR-positive cases requires further study.