Molecular epidemiology of hepatitis B viral serotypes and genotypes in taiwan

Subtypes of hepatitis B virus (HBV) have specific geographic distributions and can serve as epidemiological markers. The relationship of HBV serotypes and genotypes in Taiwan and their correlation with the domiciles of origin in 122 patients with chronic HBV infection were investigated. The serotype of HBV was determined by comparing the surface gene encoding amino acids 22-148 of the major surface protein with published sequences. Genotyping of HBV was performed by polymerase chain reaction-restriction fragment length polymorphism. Serotype adw accounted for 70% (85/122) of all HBVs, with the remaining belonging to serotype adr. All adr HBVs were genotype C, regardless of the patient's domicile. Of the 85 adw HBVs, 69 (81%) were genotype B, 10 (12%) were genotype C, 5 (6%) were genotype F and only 1 (1%) was genotype A. In the 31 patients originating from mainland China, the prevalence of adr/genotype C was higher than in the 91 Taiwanese patients (15/31 vs. 22/91; p < 0.05). The distribution of the HBV serotypes and genotypes was not significantly different between 17 patients born in Taiwan (6 adw/genotype B, 2 adw/genotype C, 1 adw/genotype F and 8 adr/genotype C) and 14 patients born in mainland China (5 adw/genotype B, 2 adw/genotype C and 7 adr/genotype C). Our results indicate that in Taiwan, most HBVs of serotype adw are genotype B, and all HBVs of serotype adr are genotype C. Patients with origins in mainland China have a higher proportion of serotype adr/genotype C infection.

Probable reinfection with hepatitis C virus in a chronic hepatitis C patient with a sustained response to combination therapy

Superinfection with hepatitis C virus (HCV) in already chronically infected subjects has been documented. Whether a complete response to antiviral therapy is associated with protective immunity against reinfection with HCV remains unknown. We describe a patient who had a sustained biochemical and virologic response with loss of intrahepatic HCV RNA after a course of combination therapy using interferon plus ribavirin. Histopathologically, the chronic hepatitis was in remission on follow-up biopsy 6 months post-therapy. Unfortunately, 34 weeks post-therapy, a flare of hepatitis with reappearance of hepatitis C viremia was noted 2 months after he received injections from a non-licensed medical provider. Analysis of the core gene sequences showed a 95% homology between the HCV strains isolated before antiviral treatment and during the hepatitis flare. The data indicated that the hepatitis flare after a period of sustained response to combination therapy in this patient could have been caused by reinfection with homotypic HCV. Our observation indicates the lack of protective immunity against reinfection with HCV in patients with chronic hepatitis C, even after successful clearance of the virus. Therefore, reinforcing the education of these subjects to avoid HCV reinfection should be stressed.

Molecular cloning and expression of woodchuck granulocyte-macrophage colony stimulating factor

Granulocyte-macrophage colony stimulating factor (GM-CSF) has immunoregulatory and antiviral effects, and may thus be promising for the treatment of chronic hepatitis B. Using woodchuck hepatitis virus (WHV)-infected woodchuck as an animal model to test the efficacy and safety of GM-CSF on the therapy of chronic hepatitis B, woodchuck GM-CSF will be required due to the apparent species-specific activity of GM-CSF. The cDNA of woodchuck GM-CSF was cloned using reverse transcription-polymerase chain reaction (RT-PCR) with primers deriving from highly conserved regions of GM-CSF genes from other species. The deduced amino acids, including the signal peptide, is 138 in length and its identities to human, murine, canine and bovine GM-CSFs are 63, 49, 63, and 63% respectively. The genomic DNA of woodchuck GM-CSF was also cloned by PCR. Its organization is highly homologous to that of human and murine GM-CSF genes, consisting of four exons and three introns. Cloned woodchuck GM-CSF was expressed transiently in 293T cells. The recombinant protein expressed was found to stimulate the growth and differentiation of woodchuck bone marrow cells, indicating the protein expressed by the cloned gene is functional. These results pave the way for future studies on the potential role of GM-CSF for the treatment of chronic hepatitis B by using this animal model.

Ribavirin enhances interferon-gamma levels in patients with chronic hepatitis C treated with interferon-alpha

Some patients with chronic hepatitis C respond to interferon (IFN)-alpha treatment, and the efficiency can be improved by combining it with ribavirin. The mechanism of this improvement is unknown. To investigate the effects of these two regimens on the immune responses in 51 patients with chronic hepatitis C, we examined the hepatitis C core antigen-specific proliferative response and cytokine production profiles, natural killer (NK) cell cytotoxicity and cytotoxic T cell function during treatment. The results are as follows: (1) both viral clearance and biochemical normalization occurred more frequently in patients receiving combination therapy; (2) the function of NK cells increased after treatment in the responders of both groups (p < 0.05); (3) the level of IFN-gamma produced by hepatitis C core antigen-stimulated peripheral blood mononuclear cells was higher in patients receiving combination therapy, especially in responders; (4) the core antigen-specific proliferative response decreased after treatment, and (5) in addition, the core-specific cytotoxic T cell activities of five responder patients also increased significantly after therapy. In conclusion, enhancement of immune responses, especially those related to type-1 T helper cell activity, may contribute to better efficacy in combining ribavirin with IFN-alpha for treatment of chronic hepatitis C.

Acute exacerbations of chronic hepatitis B are rarely associated with superinfection of hepatitis B virus

There are 7 genotypes of hepatitis B virus (HBV). Whether superinfection of HBV carriers with different HBV genotypes occurs remains unknown. We therefore determined the HBV genotype and association between superinfection and acute exacerbation of disease in a cohort of 244 patients with chronic HBV infection who had elevated serum aminotransferase levels for at least 1 year. Within this group, 103 patients experienced acute exacerbation with an annual incidence of 13%, and 20 of the 103 patients had IgM antibody to hepatitis B core antigen (IgM anti-HBc). These 20 patients had a higher prevalence of genotype C infection (65%) than the remaining 83 anti-core IgM-negative patients (40%) who also had acute exacerbations (P <.05). Detailed analysis of HBV genotypes and sequences of the variable pre-S gene were determined in serial samples from 20 patients with IgM anti-HBc-positive acute exacerbations (group A), 20 patients with IgM anti-HBc-negative acute exacerbations (group B), and 20 patients without exacerbations (group C). Two (10%) of the group A patients had virologic evidence of HBV superinfection during acute exacerbation, one superinfected with heterotypic virus and the other with homotypic virus. The newly introduced virus disappeared after the exacerbation and the original virus resumed thereafter. The calculated prevalence of HBV superinfection in the hepatitis B carriers and those with acute exacerbations was 0.8% (2 of 244) and 1.9% (2 of 103), respectively. In conclusion, superinfection of HBV on hepatitis B carriers indeed occurs and may cause acute exacerbations, albeit at a low frequency even in hyperendemic areas of HBV infection.

The conserved serine 177 in the delta antigen of hepatitis delta virus is one putative phosphorylation site and is required for efficient viral RNA replication

Hepatitis delta virus (HDV) small delta antigen (S-HDAg) plays a critical role in virus replication. We previously demonstrated that the S-HDAg phosphorylation occurs on both serine and threonine residues. However, their biological significance and the exact phosphorylation sites of S-HDAg are still unknown. In this study, phosphorylated S-HDAg was detected only in the intracellular compartment, not in viral particles. In addition, the number of phosphorylated isoforms of S-HDAg significantly increased with the extent of viral replication in transfection system. Site-directed mutagenesis showed that alanine replacement of serine 177, which is conserved among all the known HDV strains, resulted in reduced phosphorylation of S-HDAg, while the mutation of the other two conserved serine residues (2 and 123) had little effect. The S177A mutant dramatically decreased its capability in assisting HDV RNA replication, with a preferential and profound impairment of the antigenomic RNA replication. Furthermore, the viral RNA editing, a step relying upon antigenomic RNA replication, was also abolished by this mutation. These results suggested that phosphorylation of S-HDAg, with serine 177 as a presumable site, plays a critical role in viral RNA replication, especially in augmenting the replication of antigenomic RNA.

Prolonged interferon treatment after combination interferon and ribavirin therapy in patients with chronic hepatitis C: a clinical trial of interferon relapsers and non-responders

BACKGROUND AND PURPOSE

For the retreatment of chronic hepatitis C patients relapsing after, or non-responsive to, previous interferon therapy, the efficacy of combination therapy with interferon alfa plus ribavirin is superior to interferon alone. The aim of this study was to determine whether prolonged interferon alfa treatment after 24-week combination therapy can further increase the efficacy of combination therapy.

METHODS

Nineteen interferon relapsers and 17 interferon non-responders were randomly assigned to receive either interferon alfa 5 million units (MU) thrice weekly plus oral ribavirin 1,200 mg daily for 24 weeks (regimen A) or interferon alfa 5 MU thrice weekly plus oral ribavirin 1,200 mg daily for 24 weeks followed by interferon alfa 3 MU thrice weekly for another 24 weeks (regimen B). Efficacy was assessed by normalization of serum aminotransferase concentrations and disappearance of serum hepatitis C virus (HCV) RNA at the end of treatment and at 24 weeks after stopping treatment.

RESULTS

Overall, 67% of relapsers receiving regimen A and 80% of those receiving regimen B had sustained virologic responses 24 weeks after stopping treatment. In contrast, 45% of non-responders receiving regimen A and 63% of those receiving regimen B had sustained responses. The sustained response was more common in relapsers with non-1b HCV genotypes. The sustained response rate to combination therapy was 50% or more in patients with genotype 1b infection.

CONCLUSIONS

Prolonged interferon treatment after combination therapy has a comparable efficacy to combination therapy alone for the retreatment of chronic hepatitis C patients relapsing after, or non-responsive to, previous interferon therapy.

Cell cycle analysis and detection of proliferative cell nuclear antigen of the endometrium after hormone replacement therapy

BACKGROUND

To understand the effect of sequential combined hormone replacement therapy (HRT) on the postmenopausal endometrium.

METHODS

Sonographic endometrial thickness, endometrial histopathology, flow cytometric cell cycle analysis and the level of proliferative cell nuclear antigen (PCNA) were studied.

RESULTS

One hundred and thirty-eight postmenopausal women were enrolled in this study. Among which, 97 women had their endometrium being adequately obtained; the most frequent type of histopathology was normal endometrium (91.8%). Endometrial hyperplasia was found in seven patients (7.2%), including typical simple hyperplasia (n=1, 1%), focal simple hyperplasia (n=5, 5.2%) and complex hyperplasia without atypia (n=1, 1%). The proliferative fractions (PF; S plus G2-M phase) of cells from normal and hyperplastic endometrium of menopausal women after HRT were 8.18 and 8.95%, respectively, which were lower than those from 29 premenopausal women without HRT. The level of PCNA of normal and hyperplastic endometrium in postmenopausal women after HRT was about 80 and 84%, respectively, of that from premenopausal endometrium.

CONCLUSIONS

Our study showed the PF of the cell cycle and the level of PCNA were not increased in the menopausal endometrium under HRT as compared to the premenopausal controls.

Chromosomal allelic imbalance evolving from liver cirrhosis to hepatocellular carcinoma

BACKGROUND & AIMS

Cirrhotic nodules have long been assumed to be the precancerous lesions of hepatocellular carcinoma (HCC). We thus investigated the allelic imbalance (AI) in cirrhotic nodules to define the genetic aberrations in early hepatocarcinogenesis.

METHODS

One hundred eighty cirrhotic nodules from 7 female patients with HCC were collected by microdissection. Their clonality nature was assessed by examining the X chromosome methylation pattern. AI in monoclonal cirrhotic nodules and the corresponding HCCs were analyzed with microsatellite polymorphic markers.

RESULTS

One hundred one out of 180 nodules (56.1%) were monoclonal and the average fractional AI (FAI) was 21%, lower than the 40% in HCC. Their overall AI patterns differed significantly from that in HCC (P < 0.001) with FAI on 2q, 4q, 8p, and Xq higher than the mean value. Comparison of FAI in nodules (stratified by increasing total AI events) further revealed a progressive increase of FAI on 4q, 8p, and Xq. In contrast, FAI on 1p, 13q, 16q, and 17p were low in nodules but rose above the mean only in HCC.

CONCLUSIONS

About half of the cirrhotic nodules are monoclonal and already have chromosome aberrations. AI on 4q, 8p, and Xq may be the earlier mutations, whereas AI on 1p, 13q, 16q, and 17p occurs late in hepatocarcinogenesis.

Lamivudine treatment for hepatitis B reactivation in HBsAg carriers after organ transplantation: a 4-year experience

BACKGROUND

Reactivation of hepatitis B after organ transplantation in hepatitis B surface antigen (HBsAg) carriers may be fatal. In this study, we reported our experience of lamivudine treatment in HBsAg carriers who had post-transplant reactivation of hepatitis B.

METHODS

The patients were 15 men and one woman. Nine received kidney transplants, six received heart transplants, and one received a lung transplant. They developed a reactivation of hepatitis B 1-101 months (median, 14 months) after transplantation. They received lamivudine 100 mg daily on a compassionate-use basis, and had regular follow ups. The median pretreatment total serum bilirubin level was 3.0 mg/dL, and the alanine aminotransferase level was 357 U/L. Four of the 16 patients were positive for HBeAg. The serum hepatitis B virus (HBV) DNA levels were > 3000 pg/mL in 13 (81%) patients. Three were coinfected with hepatitis C virus.

RESULTS

The overall survival rate was 75%. All four fatal cases had a pretreatment total serum bilirubin level of > or = 3 mg/dL. Serum HBV-DNA soon became undetectable in 12 survivors. Of the 12 survivors, after a median treatment period of 101 weeks, a lamivudine-resistant strain with variation in the YMDD motif of the HBV polymerase gene developed in three (25%). None had significant adverse reactions to lamivudine treatment.

CONCLUSIONS

These results indicated that lamivudine is effective in the treatment of post-transplant hepatitis B reactivation, including patients with dual chronic hepatitis B and C. Early recognition of HBV reactivation and prompt lamivudine treatment are important to prevent mortality.

Hepatitis B virus variants in patients receiving lamivudine treatment with breakthrough hepatitis evaluated by serial viral loads and full-length viral sequences

Both viral loads and genome variations have been implicated in the pathogenesis of acute exacerbation of chronic hepatitis B. Hepatitis B exacerbation in patients receiving lamivudine treatment represented a unique setting to clarify their importance. Three organ recipients with posttransplantation hepatitis B exacerbation and 3 patients with chronic hepatitis B were studied. All received lamivudine treatment and their alanine aminotransferase (ALT) levels and hepatitis B virus (HBV) loads were regularly followed. Full-length genomic sequences before and during lamivudine treatment were determined in patients who had breakthrough of serum HBV DNA or elevation of serum ALT. Breakthrough of serum HBV DNA occurred after 6 to 15 months of lamivudine treatment in all. A rapid increase of viral load accompanying the emergence of tyrosine-methionine-aspartate-aspartate (YMDD) variant was followed by hepatitis B exacerbation in each patient. The mean number of nucleotide and amino acid substitutions per genome pair was equivalent in immunosuppressed or immunocompetent patients (6.3 vs. 6.3 for nucleotide, P >.05; 6.0 vs. 6.7 for amino acid, P >.05). Changes of nucleotide and amino acid beyond the YMDD motif were distributed along the whole HBV genome but none occurred within the known B-cell epitopes and human leukocyte antigen class I- or II-restricted T-cell epitopes. Our results suggest that a resurgence of viral load rather than changes of the known immunogenic viral epitopes is more closely associated with the development of hepatitis B exacerbation after the emergence of YMDD variants in patients receiving lamivudine treatment.

Specification of germ cell fates by FOG-3 has been conserved during nematode evolution

Rapid changes in sexual traits are ubiquitous in evolution. To analyze this phenomenon, we are studying species of the genus Caenorhabditis. These animals use one of two different mating systems-male/hermaphroditic, like the model organism Caenorhabditis elegans, or male/female, like C. remanei. Since hermaphrodites are essentially females that produce sperm for self-fertilization, elucidating the control of cell fate in the germ line in each species could provide the key to understanding how these mating systems evolved. In C. elegans, FOG-3 is required to specify that germ cells become sperm. Thus, we cloned its homologs from both C. remanei and C. briggsae. Each species produces a single homolog of FOG-3, and RNA-mediated interference indicates that FOG-3 functions in each species to specify that germ cells develop as sperm rather than as oocytes. What factors account for the different mating systems? Northern analyses and RT-PCR data reveal that the expression of fog-3 is always correlated with spermatogenesis. Since the promoters for all three fog-3 genes contain binding sites for the transcription factor TRA-1A and are capable of driving expression of fog-3 in C. elegans hermaphrodites, we propose that alterations in the upstream sex-determination pathway, perhaps acting through TRA-1A, allow spermatogenesis in C. elegans and C. briggsae XX larvae but not in C. remanei.

Amebic liver abscess and human immunodeficiency virus infection: a report of three cases

Invasive amebiasis rarely occurs in homosexual men and human immunodeficiency virus (HIV)-infected individuals and has not been regarded as a beacon for concomitant HIV infection. We encountered a bisexual man with a protracted course of amebic liver abscess and amebic colitis. In the presence of fever, generalized lymphadenopathy, and elevated serum aminotransferase levels, HIV infection was suspected and then confirmed by a de novo seroconversion of HIV antibody. Subsequently, we noted two consecutive patients with amebic liver abscess, also later found to be infected with HIV. The ameba obtained from these three cases was identified as Entamoeba histolytica by amplification of 16S ribosomal RNA by polymerase chain reaction and direct sequencing. This observation suggests that amebic liver abscess and colitis can be presentations for HIV infection in the Far East. Thus, the local patients with invasive amebiasis, especially those with a protracted course or with risk factors of HIV infection, should be tested for HIV.

Single nucleotide polymorphisms in intron 2 of the human interleukin-1 receptor antagonist (IL-1Ra) gene: further definition of the IL-1 beta and IL-1Ra polymorphisms in North American Caucasians and Taiwanese Chinese

Previous studies have suggested that a variable number tandem repeat (VNTR) polymorphism in the second intron of the interleukin-1 receptor antagonist (IL-1Ra) gene and the single nucleotide polymorphisms at positions -511 and +3954 of the IL-1beta gene might be associated with increased risks of chronic inflammatory diseases, autoimmune diseases and gastric cancer. In the present study, IL-1beta and IL-1Ra genotypes were analyzed among Asians in Taiwan and Caucasians in North America. We identified a novel polymorphism with 3 nucleotide substitutions in the IL-1Ra VNTR 2-repeat allele. One of the substitutions corresponds with the fourth 3' end nucleotide of the reverse primer that is often used for analysis of the IL-1Ra-associated VNTR locus. Mismatching between this primer and the 2-repeat allele can cause misleading amplification results when stringent conditions are used for annealing. The estimated haplotype frequencies of the variant IL-1 genes were significantly different between Taiwanese and Caucasians. The frequency of the pro-inflammatory IL-1Ra 2-repeat allele was significantly lower in Taiwanese than in Caucasians. In contrast, the frequencies of the pro-inflammatory IL-1beta -511T allele and +3954C allele were significantly higher among Taiwanese compared with Caucasians.

A cGMP-dependent protein kinase is implicated in wild-type motility in C. elegans

In mammals, cyclic GMP and cGMP-dependent protein kinases (cGKs) have been implicated in the regulation of many neuronal functions including long-term potentiation and long-term depression of synaptic efficacy. To develop Caenorhabditis elegans as a model system for studying the neuronal function of the cGKs, we cloned and characterized the cgk-1 gene. A combination of approaches showed that cgk-1 produces three transcripts, which differ in their first exon but are similar in length. Northern analysis of C. elegans RNA, performed with a probe designed to hybridize to all three transcripts, confirmed that a major 3.0 kb cgk-1 transcript is present at all stages of development. To determine if the CGK-1C protein was a cGMP-dependent protein kinase, CGK-1C was expressed in SF:9 cells and purified. CGK-1C shows a K(a) of 190 +/- 14 nM for cGMP and 18.4 +/- 2 microM for cAMP. Furthermore, CGK-1C undergoes autophosphorylation in a cGMP-dependent manner and is inhibited by the commonly used cGK inhibitor, KT5823. To determine which cells expressed CGK-1C, a 2.4-kb DNA fragment from the promoter of CGK-1C was used to drive GFP expression. The CGK-1C reporter construct is strongly expressed in the ventral nerve cord and in several other neurons as well as the marginal cells of the pharynx and intestine. Finally, RNA-mediated interference of CGK-1 resulted in movement defects in nematode larvae. These results provide the first demonstration that cGMP-dependent protein kinase is present in neurons of C. elegans and show that this kinase is required for normal motility.

Dinosaur's feather and chicken's tooth? Tissue engineering of the integument

The integument forms the interface between animals and the environment. During evolution, diverse integument and integument appendages have evolved to adapt animals to different niches. The formation of these different integument forms is based on the acquisition of novel developmental mechanisms. This is the way Nature does her tissue/organ engineering and experiments. To do tissue engineering of the integument in the new century for medical applications, we need to learn more principles from developmental and evolutionary studies. A novel diagram showing the evolution and development of integument complexity is presented, and the molecular pathways involved discussed. We then discuss two examples in which the gain and loss of appendages are modulated: transformation of avian scale epidermis into feathers with mutated beta catenin, and induction of chicken tooth like appendages with FGF, BMP and feather mesenchyme.

Androgen-receptor gene CAG repeats, plasma testosterone levels, and risk of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Worldwide, hepatocellular carcinoma (HCC) is more prevalent in men than in women, suggesting that sex hormones and/or X-chromosome-linked genes may be involved in hepatocarcinogenesis. We investigated the association of a trinucleotide (CAG) repeat in the androgen receptor (AR) gene (located on the X chromosome) termed "AR-CAG repeats," levels of plasma testosterone, and the risk of HCC in Taiwanese men. Chronic hepatitis B virus (HBV) infection, which is associated with risk of HCC, is hyperendemic in Taiwan.

METHODS

We compared the number of AR-CAG repeats in 285 HBV carriers with HCC and in 349 HBV carriers without HCC. We also conducted a nested case--control study on participants in a cohort study. Blood was collected prospectively from 110 case patients and 239 control subjects and was used to determine the number of AR-CAG repeats and plasma testosterone level. All statistical tests were two-sided.

RESULTS

The overall odds ratio (OR) for HCC was 1.72 (95% confidence interval [CI] = 1.03--2.89) for HBV carriers with 20 or fewer AR-CAG repeats compared with those with more than 24 repeats. This association was observed only in patients with late-onset HCC (OR = 2.37; 95% CI = 1.28--4.38). In the nested case-control study, HBV carriers in the highest tertile of testosterone levels had a statistically significantly increased risk of HCC (OR = 2.06; 95% CI = 1.14--3.70) compared with those in the lowest tertile. Elevated testosterone was more strongly associated with early-onset (OR = 4.67; 95% CI = 1.41--15.38) than late-onset disease. HBV carriers with 20 or fewer AR-CAG repeats and higher testosterone levels had a fourfold increase in HCC risk compared with those with more than 24 repeats and testosterone levels in the lowest tertile.

CONCLUSIONS

Higher levels of androgen signaling, reflected by higher testosterone levels and 20 or fewer AR-CAG repeats, may be associated with an increased risk of HBV-related HCC in men.

Efficacy of consensus interferon in the treatment of chronic hepatitis C

BACKGROUND AND AIMS

Consensus interferon (CIFN) is a newly developed type I interferon. The aim of this study was to investigate the safety and efficacy of CIFN in the treatment of patients with chronic hepatitis C and to determine the predictors for sustained response.

METHODS

Patients were randomized to receive 3 micrograms or 9 micrograms CIFN three times a week for 24 weeks, followed by 24 weeks of observation. Efficacy was assessed by normalization of serum transaminase levels and disappearance of serum hepatitis C virus (HCV)-RNA at the end of treatment and at 24 weeks after stopping treatment. Histologic response was defined as a decrease of at least two points in the Knodell necroinflammatory score at week 48 and was compared with baseline.

RESULTS

There were no serious adverse effects related to CIFN therapy. Overall, 44% of patients receiving 3 micrograms and 48% of patients receiving 9 micrograms had normalization of serum transaminase levels and disappearance of HCV viremia at the end of treatment. At 24 weeks after stopping treatment, 16% of patients in receiving 9 micrograms and 12% of patients receiving 3 micrograms had sustained responses. The histologic responses in patients receiving 9 micrograms and those receiving 3 micrograms were 60% and 36%, respectively. The necroinflammatory score was significantly reduced from baseline to week 48 in both groups. In addition, bodyweight < 60 kg and pretreatment serum HCV-RNA level < 0.5 MEq/mL can serve as predictors for sustained response to CIFN treatment.

CONCLUSIONS

These findings suggest that 9 micrograms CIFN is safe and effective in the treatment of patients with chronic hepatitis C.

Hepatitis B genotypes and the response to interferon therapy

BACKGROUND/AIMS

Possible pathogenic differences among hepatitis B virus (HBV) genotypes have been observed; however, the response to interferon therapy among HBV genotypes remains unknown. We therefore analyzed the efficacy of interferon alfa in the treatment of chronic hepatitis B patients with different HBV genotypes.

METHODS

Fifty-eight genotype B or C infected chronic hepatitis B patients who had been treated with interferon alfa-2b were retrospectively studied. The response to interferon was defined as normalization of serum aminotransferase level, loss of hepatitis B e antigen and HBV DNA 48 weeks post-treatment.

RESULTS

Baseline data of both groups of patients were comparable; however, genotype C patients had a higher serum aminotransferase level and a higher frequency of core promoter mutation. The response rate was 41% and 15% in genotype B and C patients, respectively (p=0.045). In those with higher serum aminotransferase levels, the response rate was 50% and 17%, respectively (p=0.025). Additionally, younger age and genotype B infection may predict a better response to interferon alfa.

CONCLUSIONS

HBV genotype C, compared to genotype B, is associated with a higher frequency of core promoter mutation, and a lower response rate to interferon alfa therapy.

Hepatic leiomyomatous neoplasm associated with Epstein Barr virus infection in an adult with acquired immunodeficiency syndrome

Focal lesions in the liver in patients with acquired immunodeficiency syndrome (AIDS) pose an important clinical problem. Hepatic smooth-muscle tumor is rare in AIDS patients and has been reported mostly in children. We describe a 32-year-old male AIDS patient, with previous disseminated tuberculosis, who developed a small tumor in the liver. Liver biopsy disclosed an unusual hepatic leiomyomatous neoplasm that was associated with Epstein Barr virus infection. It differed from the more common Kaposi's sarcoma and presented a relatively benign course.

Interspousal transmission of TT virus: low efficiency and lack of apparent risk factors

BACKGROUND

The TT virus (TTV) is a newly identified human DNA virus and little is known about its non-parenteral transmission. The aim of the present study was to explore the prevalence of TTV infection in spouses of index cases and the related risk factors.

METHODS

Serum TTV-DNA was studied in spouses of 41 subjects with TT viremia. For couples in which both husband and wife had TT viremia, nucleotide sequences of the open reading frame-1 region were analyzed by phylogenetic tree constructions.

RESULTS

Three (7%) of 41 spouses were positive for TTV-DNA. No differences were noted between index patients with seropositive spouses and those without seropositive spouses with regard to clinical characteristics, including parenteral risk factors and exposure duration. Nucleotide sequence comparison and phylogenetic tree analysis of the viral genome in three TTV-infected couples revealed the isolates to be closely related in two, with a homology of 97 and 98%, respectively.

CONCLUSIONS

These results suggest that interspousal transmission of TTV does occur; however,the efficiency of transmission is low compared with hepatitis C virus and GB virus-C. There are no apparent risk factors for transmission between spouses and further studies are needed to clarify other modes of non-parenteral transmission.

Role of N-acetyltransferase polymorphisms in hepatitis B related hepatocellular carcinoma: impact of smoking on risk

BACKGROUND

Persistent infection with hepatitis B virus (HBV) causes chronic phasic necroinflammation and regenerative proliferation in the liver. The sustained hepatocellular proliferation may render chronic HBV carriers more susceptible to the effects of environmental carcinogens. Aromatic amines are potential hepatocarcinogens in humans. N-acetyltransferase (NAT) is involved in the metabolic activation and detoxification of these compounds.

AIMS

To investigate if genetic polymorphisms in N-acetylation are related to hepatocellular carcinoma (HCC) among chronic HBV carriers.

METHODS

Genotyping of NAT1 and NAT2 was performed using polymerase chain reaction-restriction fragment length polymorphism on peripheral leucocyte DNA from 151 incident cases of HCC and 211 controls. All subjects were male, and were chronic HBV surface antigen carriers.

RESULTS

A significant association between NAT2 genetic polymorphism and HCC was observed among chronic HBV carriers who were smokers but not among those who were non-smokers. For smoking HBV carriers, the odds ratios of developing HCC for those heterozygous and homozygous for the NAT2*4 functional allele compared with those without any copies of the functional allele (reference group) were 2.67 (95% confidence interval 1.15-6.22) and 2.58 (95% confidence interval 1.04-6.43), respectively. The interaction between cigarette smoking and the presence of the NAT2*4 allele just failed to reach statistical significance (p=0.06). No association between NAT1 genotype and HCC was evident overall or within the smoking stratified subgroups.

CONCLUSIONS

Our results suggest that NAT2 activity may be particularly critical in smoking related hepatocarcinogenesis among chronic HBV carriers. Our data also indirectly support a role for tobacco smoke derived aromatic amines in the aetiology of HCC.

Hepatocyte growth factor stimulates the growth and activates mitogen-activated protein kinase in human hepatoma cells

Hepatocyte growth factor (HGF) is a potent mitogen for hepatocytes and various epithelial cells. Unexpectedly, it has been reported to inhibit the growth of hepatoma cells in vitro. To clarify this phenomenon, we examined the effects of recombinant baculovirus-expressed HGF on the growth of 6 human hepatoma cell lines. The growth of Hep3B and HepG2 cells was markedly stimulated to 1.8- and 1.7-fold, respectively, PLC/PRF/5 to 1.4-fold, and SK-Hep-1 to 1.2-fold in a dose-dependent manner under HGF concentrations below 20 ng/ml. Neither HuH-7 nor HCC36 were affected. None of these cells were inhibited. All these cells expressed c-Met, the membrane receptor for HGF, and their c-Met would be activated to be phosphorylated upon addition of HGF. They also contained the ERK2 subgroup of mitogen-activated protein kinases (MAPKs). When HGF was added, their ERK2 would also be phosphorylated. The extent of ERK2 phosphorylation was partially correlated to their growth response to HGF. In conclusion, HGF could stimulate the growth of certain human hepatoma cells, probably through activation of c-Met and MAPKs.

Mechanism of abnormal elastin gene expression in the pinguecular part of pterygia

Elastodysplasia and elastodystrophy are two known manifestations in the conjunctival, ie, pinguecular, part of pterygia. But the mechanisms are still not understood. The purpose of this study is to investigate the mechanism of enhanced elastin gene expression in fibroblasts from the pinguecular part of pterygia, which is related to abnormal elastic fiber expression in the pinguecular part of pterygia. Elastin in surgical specimens of normal conjunctiva and the pinguecular part of pterygia from age-matched patients was detected by immunohistochemical staining. Northern hybridization and quantification of radiolabeled tropoelastin were performed in conjunctival fibroblasts cultured under different doses of ultraviolet (UV) B irradiation, and in cultured pinguecular fibroblasts from pterygia. In vitro translation was also performed to analyze the tropoelastin production in rabbit reticulocyte lysate. The level of tropoelastin in reticulolysates from UV-treated conjunctival and pinguecular fibroblasts of pterygia was higher than in normal conjunctival fibroblasts. The coding sequence and 3'- untranslated region of tropoelastin mRNAs were amplified by reverse transcription-polymerase chain reaction, and mutations were checked by DNA sequencing. Immunohistochemical staining revealed elastin in pinguecular subepithelial connective tissues of pterygia, but not in normal conjunctiva. Tropoelastin mRNA levels were not elevated in cultured pinguecular or conjunctival fibroblasts with or without ultraviolet B irradiation. However, tropoelastin synthesis was enhanced in culture medium of pinguecular and UV-irradiated conjunctival fibroblasts, but not in normal conjunctival fibroblasts. Direct DNA sequencing revealed mutations in the 3'-untranslated region but not in the coding sequence of tropoelastin mRNA, in both pinguecular and UV-irradiated conjunctival fibroblasts. The increased expression of tropoelastin in pinguecular and UV-irradiated fibroblasts is not a result of increased levels of steady-state mRNA, but is a result of posttranscriptional modification of tropoelastin.

[Assay of Epstein-Barr virus in nasopharyngeal tissues and serum of patients with nasopharyngeal carcinoma]

OBJECTIVE

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC). Determination of EBV-VCA-IgA, EBV-EA-IgA in serum and assay of EBV DNA (PCR) in biopsy tissue has been used for diagnosis of NPC. This paper evaluated the value of the three determinations for diagnosis of NPC.

METHOD

146 patients were investigated. For each patient determination of EBV-VCA-IgA, EBV-EA-IgA in serum and EBV-DNA (PCR) in biopsy tissue were performed with double-blind studies, of 146 patients, 76 were NPC and 70 non nasopharyngeal carcinoma as control, identified with histopathological examination. The differences of the determinations between NPC and control were compared statistically with chi 2-test.

RESULT

Of 76 NPC, the positive rates of EBV-DNA (PCR), EBV-VCA-IgA and EBV-EA-IgA were 90.8%, 75.0% and 26.3% respectivelly. For 70 control cases, the positive rates 2.9%, 38.6% and 2.9% respectivelly (P < 0.005).

CONCLUSION

Our results suggested that assay of EBV-DNA (PCR) has better sensitivity and specificity than EBV-VCA-IgA and EBV-EA-IgA for diagnosis of NPC.

Chromosomal changes and clonality relationship between primary and recurrent hepatocellular carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is highly malignant and prone to recur after surgical treatment. Differentiation between a true relapse of HCC and a second primary tumor is of clinical importance. However, no convenient method is currently available.

METHODS

Comparative genomic hybridization (CGH) was used to analyze 31 pairs of initial and recurrent HCC samples obtained from patients undergoing 2 consecutive surgeries. The resulting chromosomal aberration profiles were used as genomic fingerprints to determine tumor clonalities and their relationships.

RESULTS

Eleven recurrent tumors with high clonal relationship (CR) values (>0.95) were found to be relapsed HCCs, and 11 tumors with CR values close to 0 were found to be second primary HCCs. The other 9 paired samples had inconclusive CR values between 0.95 and 0.4. Two were confirmed by hepatitis B virus integration and X chromosome inactivation analysis to be de novo cancers (CR values, 0.35 and 0. 23, respectively). Initial HCCs that subsequently relapsed accumulated more chromosomal aberration events than those that developed de novo HCC (mean, 16.1 +/- 4.5 vs. 5.4 +/- 4.8 events; P < 0.01). Also, they more frequently showed gains on chromosome arms 3q, 6p, 8q, and 17q and losses on 4q and 16p.

CONCLUSIONS

CGH is useful for chromosomal aberration study and tumor clonality analysis. More and characteristic genomic changes in the initial HCC suggest that subsequent tumor recurrence is a true relapse.

Familial risk of hepatocellular carcinoma among chronic hepatitis B carriers and their relatives

BACKGROUND

Familial predisposition as a risk factor for hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) carriers has not been thoroughly explored.

METHODS

The HCC risk associated with having parents and/or siblings with HCC was evaluated by use of a cohort study of 4808 male HBV carriers. A case-control family study was also conducted on data from first-degree relatives of 553 HBV carriers who had newly diagnosed HCC (case subjects) and 4684 HBV carriers without HCC (control subjects).

RESULTS

In the cohort study, HBV carriers with a family history of HCC had a multivariate-adjusted rate ratio for HCC of 2.41 (95% confidence interval [CI] = 1.47-3.95) compared with HBV carriers without a family history of HCC. For carriers with two or more affected relatives, the ratio increased to 5.55 (95% CI = 2.02-15.26). Cumulative HCC risk by age 70 years was 235.6 per 1000 (95% CI = 95. 3-375.9 per 1000) for HBV carriers with family history compared with 88.9 per 1000 (95% CI = 67.9-109.9 per 1000) for those without. In the case-control family study, first-degree relatives of case subjects were more likely to have HCC (age-sex-adjusted odds ratio [OR] = 2.57; 95% CI = 2.03-3.25) than first-degree relatives of control subjects. The excess risk of HCC among relatives was particularly evident in siblings (sisters-age-adjusted OR = 4.55 [95% CI = 2.22-9.31]; brothers-age-adjusted OR = 3.73 [95% CI = 2. 64-5.27]), but it was also observed in parents. The cumulative risk of HCC to age 80 years was 83.0 per 1000 among relatives of case subjects and 42.0 per 1000 among relatives of control subjects. Among relatives of case subjects, the cumulative risk of HCC was greater if the case subjects were diagnosed before age 50 years (two-sided P =.047). Liver cirrhosis was 2.29 (95% CI = 1.68-3.11) times more frequent in relatives of case subjects than in relatives of control subjects.

CONCLUSIONS

First-degree relatives of patients with HBV-related HCC appear to be at increased risk of HCC and should be considered in the formulation of HCC-screening programs.

TT virus infection in patients with chronic hepatitis B or C: influence on clinical, histological and virological features

Concomitant infection with TT virus and hepatitis B virus (HBV) or hepatitis C virus (HCV) is common. However, the effect of TTV infection on chronic hepatitis B or C is unknown. The prevalence of TTV infection, the effect of TTV infection on the clinical, histological and virological features of patients with chronic hepatitis B or C, and the influence of TTV infection on the HCV response to interferon alfa therapy were studied. A total of 100 asymptomatic hepatitis B surface antigen carriers, 220 patients with HBV-related chronic liver diseases, and 110 patients with chronic hepatitis C treated with interferon alfa (3 million units subcutaneously three times a week for 24 weeks) were enrolled. Serum HCV RNA and serum TTV DNA were detected by the polymerase chain reaction (PCR). Serum HBV DNA and serum HCV RNA level were quantified by branched DNA assays. Infection with TTV was detected in 21.5% of HBV carriers and 37% of HCV carriers. TTV infection had little effect on the clinicopathological course of chronic HBV infection. In chronic hepatitis C, clinical features, histological severity, serum HCV RNA levels, and the response to interferon alfa therapy did not differ between those with and without TTV infection. The loss of serum TTV DNA did not correlate with the biochemical response as did in the loss of serum HCV RNA. In conclusion, TTV infection is found frequently in patients with chronic hepatitis B or C in Taiwan; however, coinfection with TTV does not affect the clinicopathological course of chronic hepatitis B or C and the response to interferon alfa therapy.

Low incidence of hepatitis C virus transmission between spouses: a prospective study

BACKGROUND

Interspousal transmission of hepatitis C virus (HCV) has been documented; however, the annual risk of interspousal transmission remains unclear.

METHODS

A long-term prospective study to define the risk of interspousal transmission of HCV was conducted. One hundred and twelve index patients with chronic hepatitis C and their anti-HCV seronegative spouses were enrolled.

RESULTS

The mean follow-up period was 45.9 months. Antibodies to HCV (anti-HCV) and HCV-RNA were tested for in each seronegative spouse every year. Seroconversion of anti-HCV occurred in only one spouse, 2 years after enrollment, with a concomitant acute hepatitis. This subject and his spouse were infected with HCV genotype 1b. Nucleotide sequence comparison of the hypervariable region of their HCV genomes showed a homology of 98%. Further phylogenetic analysis suggested that they had virtually the same isolate. Accordingly, the annual risk of interspousal transmission of HCV infection was 0.23% per year.

CONCLUSIONS

These findings suggest a low incidence of interspousal transmission of HCV; however, the risk may be cumulative and such couples should be educated to avoid HCV infection from their spouses.

TT virus infection in patients with chronic hepatitis B or C: influence on clinical, histological and virological features

Concomitant infection with TT virus and hepatitis B virus (HBV) or hepatitis C virus (HCV) is common. However, the effect of TTV infection on chronic hepatitis B or C is unknown. The prevalence of TTV infection, the effect of TTV infection on the clinical, histological and virological features of patients with chronic hepatitis B or C, and the influence of TTV infection on the HCV response to interferon alfa therapy were studied. A total of 100 asymptomatic hepatitis B surface antigen carriers, 220 patients with HBV-related chronic liver diseases, and 110 patients with chronic hepatitis C treated with interferon alfa (3 million units subcutaneously three times a week for 24 weeks) were enrolled. Serum HCV RNA and serum TTV DNA were detected by the polymerase chain reaction (PCR). Serum HBV DNA and serum HCV RNA level were quantified by branched DNA assays. Infection with TTV was detected in 21.5% of HBV carriers and 37% of HCV carriers. TTV infection had little effect on the clinicopathological course of chronic HBV infection. In chronic hepatitis C, clinical features, histological severity, serum HCV RNA levels, and the response to interferon alfa therapy did not differ between those with and without TTV infection. The loss of serum TTV DNA did not correlate with the biochemical response as did in the loss of serum HCV RNA. In conclusion, TTV infection is found frequently in patients with chronic hepatitis B or C in Taiwan; however, coinfection with TTV does not affect the clinicopathological course of chronic hepatitis B or C and the response to interferon alfa therapy.

Hepatitis B genotypes correlate with clinical outcomes in patients with chronic hepatitis B

BACKGROUND & AIMS

Six genotypes (A-F) of hepatitis B virus (HBV) have been identified; however, the genotype-related differences in the pathogenicity of HBV remain unknown. Therefore, we investigated the prevalence of HBV genotypes in Taiwan and the association between distinct genotypes and severity of liver disease in a cross-sectional study.

METHODS

Using a molecular method, HBV genotypes were determined in 100 asymptomatic carriers and in 170 patients with histologically verified chronic liver disease and hepatocellular carcinoma (HCC).

RESULTS

All genotypes except genotype E were identified in Taiwan, and genotypes B and C were predominant. Genotype C was prevalent in patients with cirrhosis and in those with HCC who were older than 50 years compared with age-matched asymptomatic carriers (60% vs. 23%, P < 0.001, and 41% vs. 15%, P = 0.005, respectively). Genotype B was significantly more common in patients with HCC aged less than 50 years compared with age-matched asymptomatic carriers (80% vs. 52%, P = 0.03). This predominance was more marked in younger patients with HCC (90% in those aged </=35 years), most of whom did not have cirrhosis.

CONCLUSIONS

Our data suggest that HBV genotype C is associated with more severe liver disease and genotype B may be associated with the development of HCC in young Taiwanese. However, additional large-scale longitudinal studies are needed to confirm the relationship of HBV genotypes to liver disease severity and clinical outcomes.

Impact of human genome research on medicine--the initial Taiwan experience

The human genome contains at least 80,000 genes, and each carries out its unique biologic function in the human body. Gene mutation and variation may result in hereditary disease, cancer, hypertension, and even susceptibility to infectious diseases. A complete compilation of all human genes (the human genome) should allow a better understanding of the role of specific genes in diseases and, consequently, better design of effective treatments. The human genome project (HGP) is scheduled to be completed in 2003. This article reviews the novel technology used in the HGP and the new information that will be generated. The results will influence medical practice greatly. Indeed, as in the forthcoming era of genomic medicine, a battery of gene tests is likely to be as routine as blood chemistry tests are today. The impacts are to be felt soon and medical professionals should be ready to grasp and apply new knowledge as it becomes available to better serve their patients. We also describe how the findings from the HGP might be used to solve locally important medical problems, using the examples of genomic research in liver and nasopharyngeal cancers. Finally, because the HGP has raised many new ethical, legal, and social challenges that should often take precedence over the problems of technology, an overview of these issues is also provided.

A novel member of the tob family of proteins controls sexual fate in Caenorhabditis elegans germ cells

Although many cell fates differ between males and females, probably the most ancient type of sexual dimorphism is the decision of germ cells to develop as sperm or as oocytes. Genetic analyses of Caenorhabditis elegans suggest that fog-3 might directly control this decision. We used transformation rescue to clone the fog-3 gene and show that it produces a single major transcript of approximately 1150 nucleotides. This transcript is predicted to encode a protein of 263 amino acids. One mutation causes a frame shift at the sixth codon and is thus likely to define the null phenotype of fog-3. Although the carboxyl-terminus of FOG-3 is novel, the amino-terminal domain is similar to that of the Tob, BTG1, and BTG2 proteins from vertebrates, which might suppress proliferation or promote differentiation. This domain is essential for FOG-3 activity, since six of eight missense mutations map to this region. Furthermore, this domain of BTG1 and BTG2 interacts with a transcriptional regulatory complex that has been conserved in all eukaryotes. Thus, one possibility is that FOG-3 controls transcription of genes required for germ cells to initiate spermatogenesis rather than oogenesis. This model implies that FOG-3 is required throughout an animal's life for germ cells to initiate spermatogenesis. We used RNA-mediated interference to demonstrate that fog-3 is indeed required continuously, which is consistent with this model.

Liver and peripheral blood mononuclear cells are not major sites for GB virus-C/hepatitis G virus replication

The pathogenesis and replication sites of GB virus-C/hepatitis G virus (GBV-C/HGV) in humans remain unclear. The presence of GBV-C/HGV and hepatitis C virus (HCV) RNA sequences in matched serum, peripheral blood mononuclear cells (PBMC) and liver samples in 10 patients with GBV-C/HGV infection, 8 of whom were coinfected with HCV was explored. Positive- and negative-strand GBV-C/HGV and HCV RNA were detected by strand-specific reverse-transcription polymerase chain reaction (RT-PCR), and virus titers were quantified by competitive PCRs. Positive-strand GBV-C/HGV RNA was detected in 7 of 10 PBMC samples of the patients with serum GBV-C/HGV RNA, but negative-strand GBV-C/HGV RNA was not found in these cells. Positive-strand GBV-C/HGV RNA was found in 9 liver samples, and 2 (22%) of them also had negative strand. In contrast, negative-strand HCV RNA was frequently found in PBMC and liver samples. A positive correlation between the titer of viral RNA in liver tissue and that in serum sample was demonstrated in HCV infection, but not in GBV-C/HGV infection. These findings suggest that liver and PBMC are not the major replication sites for GBV-C/HGV and that GBV-C/HGV is not a primary hepatotropic virus.

Crystal structure of UvrB, a DNA helicase adapted for nucleotide excision repair

Nucleotide excision repair (NER) is a highly conserved DNA repair mechanism. NER systems recognize the damaged DNA strand, cleave it on both sides of the lesion, remove and newly synthesize the fragment. UvrB is a central component of the bacterial NER system participating in damage recognition, strand excision and repair synthesis. We have solved the crystal structure of UvrB in the apo and the ATP-bound forms. UvrB contains two domains related in structure to helicases, and two additional domains unique to repair proteins. The structure contains all elements of an intact helicase, and is evidence that UvrB utilizes ATP hydrolysis to move along the DNA to probe for damage. The location of conserved residues and structural comparisons allow us to predict the path of the DNA and suggest that the tight pre-incision complex of UvrB and the damaged DNA is formed by insertion of a flexible beta-hairpin between the two DNA strands.

Invasive amoebiasis: an emerging parasitic disease in patients infected with HIV in an area endemic for amoebic infection

OBJECTIVES

To describe the incidence and presentations of invasive amoebiasis (IA) in patients with HIV infection in an area endemic for amoebic infection and to assess the role of the indirect haemagglutination (IHA) assay in the diagnosis of IA in HIV-infected patients.

DESIGN

Retrospective study of 18 cases of IA and HIV infection.

SETTING

A university hospital, the largest centre for management of HIV-associated complications in Taiwan.

METHODS

Medical, microbiological and histopathological records of 296 HIV-infected patients and serological data of IHA assay of 126 HIV-infected patients were reviewed to identify cases of IA from 23 June 1994 to 31 March 1999. An IHA titre > or = 1 : 128 was considered positive. Clinical characteristics of HIV-infected patients with IA and without IA were compared.

RESULTS

Eighteen of the 296 patients (6.1%) with HIV infection were diagnosed with IA: 12 patients were diagnosed with definite IA and six with probable IA. The clinical manifestations included amoebic colitis (13 patients), amoebic liver abscess (nine), both colitis and abscess (four), and pleural effusion (two). IA was the initial presentation of HIV infection in nine patients. Co-infection with other enteric pathogens was diagnosed in six patients with IA. Compared with the 161 patients without IA who were newly diagnosed with HIV infection, the nine patients with IA had a higher median CD4+ lymphocyte count (202 x 10(6)/l versus 33 x 10(6)/l; P = 0.0017), were less likely to be diagnosed with AIDS (55.6% versus 85.4%; P = 0.039), and had fewer concurrent AIDS-defining illnesses (median number 0 versus 2; P = 0.003). Estimated mean survival duration was not significantly different between the two groups (597 days versus 611 days). Fourteen out of 126 patients (11.1%) had an IHA titre > or = 1 : 128. Of the 18 patients diagnosed with IA, 13 had a titre > or = 1 : 128. The sensitivity of IHA assay in the diagnosis of IA was 72.2% (13 out of 18) and the specificity was 99.1% (107 out of 108). The positive predictive value of IHA test for IA of this patient population was 92.9% (13 out of 14) whereas the negative predictive value was 95.5% (107 out of 112).

CONCLUSION

IA is an increasingly important parasitic disease among patients with HIV infection in Taiwan. IHA assay has a good specificity and high negative predictive value in diagnosis of IA.

Characterization of the phosphorylated forms and the phosphorylated residues of hepatitis delta virus delta antigens

Hepatitis delta virus (HDV) replication requires both the cellular RNA polymerase and one virus-encoded protein, small delta antigen (S-HDAg). S-HDAg has been shown to be a phosphoprotein, but its phosphorylation status is not yet clear. In this study, we employed three methods to address this question. A special two-dimensional gel electrophoresis, namely, nonequilibrium pH gradient electrophoresis, was used to separate the very basic S-HDAg. By carefully adjusting the pH of solubilization solution, the ampholyte composition, and the appropriate electrophoresis time periods, we were able to clearly resolve S-HDAg into two phosphorylated isoforms and one unphosphorylated form. In contrast, the viral large delta antigen (L-HDAg) can only be separated into one phosphorylated and one unphosphorylated form. By metabolic (32)P labeling, both immunoprecipitated S-HDAg and L-HDAg were found to incorporate radioactive phosphate. The extent of S-HDAg phosphorylation was increased upon 12-O-tetradecanoylphorbol-13-acetate treatment, while that of L-HDAg was not affected. Finally, phosphoamino acid analysis identified serine and threonine as the phospho residues in the labeled S-HDAg and only serine in the L-HDAg. Therefore, HDV S- and L-HDAgs differ in their phosphorylation patterns, which may account for their distinct biological functions.

Prevalence and implication of TT virus infection: minimal role in patients with non-A-E hepatitis in Taiwan

TT virus (TTV) is a newly identified human DNA virus and little is known about its clinical significance. The aim of the study was to explore the prevalence of TTV infection in different risk populations and in patients with various liver diseases. Viral DNA was studied in 190 high-risk individuals, 97 household contacts, 52 patients with acute hepatitis A, 32 patients with non-A-E hepatitis including 13 fulminant hepatitis, 200 asymptomatic hepatitis B surface antigen (HBsAg) carriers, 100 patients with chronic hepatitis C, and 100 healthy adults. TTV infection was more frequent in high-risk groups (26-70%), patients with acute or fulminant non-A-E hepatitis (42-45%), and hepatitis C carriers (36%) than in healthy adults (10%) and hepatitis B carriers (15%). However, most of subjects with TTV infection alone had no or only mild hepatitis, and the same rate of TTV DNA in pre-hepatitis serum samples and constant serum TTV titers during hepatitis episodes were observed in two patients with acute non-A-E hepatitis. Phylogenetic analysis of the Taiwanese TTV isolates showed genetic heterogeneity and most (68%) isolates were TTV type 1. No particular strain was found to be associated with fulminant non-A-E hepatitis.

Prevalence and implication of TT virus infection: minimal role in patients with non-A-E hepatitis in Taiwan

TT virus (TTV) is a newly identified human DNA virus and little is known about its clinical significance. The aim of the study was to explore the prevalence of TTV infection in different risk populations and in patients with various liver diseases. Viral DNA was studied in 190 high-risk individuals, 97 household contacts, 52 patients with acute hepatitis A, 32 patients with non-A-E hepatitis including 13 fulminant hepatitis, 200 asymptomatic hepatitis B surface antigen (HBsAg) carriers, 100 patients with chronic hepatitis C, and 100 healthy adults. TTV infection was more frequent in high-risk groups (26-70%), patients with acute or fulminant non-A-E hepatitis (42-45%), and hepatitis C carriers (36%) than in healthy adults (10%) and hepatitis B carriers (15%). However, most of subjects with TTV infection alone had no or only mild hepatitis, and the same rate of TTV DNA in pre-hepatitis serum samples and constant serum TTV titers during hepatitis episodes were observed in two patients with acute non-A-E hepatitis. Phylogenetic analysis of the Taiwanese TTV isolates showed genetic heterogeneity and most (68%) isolates were TTV type 1. No particular strain was found to be associated with fulminant non-A-E hepatitis.

Hepatitis B virus infection and hepatocellular carcinoma: molecular genetics and clinical perspectives

Chronic hepatitis B progresses across a spectrum of asymptomatic carriers, active hepatitis, and liver cirrhosis. With more advanced disease stage, the risk for developing hepatocellular carcinoma (HCC) becomes higher. Recent studies suggest that this progressive risk may reflect an accumulation of multistage genetic mutations in the chromosomes of affected hepatocytes. Mutations of the known candidate genes such as p53 and beta-catenin have been found. Recent genome-wide analysis of HCC chromosomes by comparative genomic hybridization or loss of heterozygosity have identified more new loci implicated in hepatocarcinogenesis. Persistent hepatitis B is essential for inducing these mutations through immune-mediated injuries of the hepatocytes and the resulting hyperplasia. Prevention of hepatitis B by active immunization effectively interrupts persistent viral infections in children and subsequently reduces the risk of childhood HCC. Treatment for chronic hepatitis B by interferon or antiviral analogues can control hepatitis B activity, but its effect on controlling HCC remains to be seen. Insights for the hepatocarcinogenesis process should come from a multidisciplinary collaboration to explore important viral and host genes so that new approaches to diagnosis and treatment can be developed.

Protamine enhances the efficiency of liposome-mediated gene transfer in a cultured human hepatoma cell line

Protamine, used clinically as an antidote for heparin, is a small protein with high arginine content and is potent in folding DNA. Protamine and DNA can form a compact structure, protecting DNA from digestion by intracellular enzymes. Protamine may, therefore, enhance the efficiency of gene transfer. In this study, we tested the ability of protamine to improve liposome-mediated gene transfer efficiency in a human hepatoma cell line. The results of a preliminary gel retardation assay indicated that 10 micrograms was the minimal amount of protamine sulfate needed to completely bind 5 micrograms of a plasmid containing a reporter gene, green fluorescent protein (GFP). For transfection assays, protamine (0, 10, 50, 100, and 500 micrograms) was added to a DNA-liposome mixture (5 micrograms DNA and 20 micrograms of a mixed formulation of 2,3-dioleyloxy-N-[2(sperminecarboxamido)ethyl]-N, N-dimethyl-1-propanaminium trifluoroacetate and dioleoylphosphatidylethanolamine) to transfect cultured Huh7 cells. Transfected cells (those expressing GFP) were counted by using flow cytometry. The expression index (EI) was calculated as the transfection efficiency (% of transfected cells) with protamine divided by the transfection efficiency with DNA and liposome only. Our results show that protamine sulfate (in a range of 10-100, 10 micrograms being most efficient) addition to the liposome-DNA mixture significantly increases the EI, and transfection efficiency of GFP in Huh7 cells.

Bacterial infections associated with hepatic arteriography and transarterial embolization for hepatocellular carcinoma: a prospective study

Sepsis and liver abscess are serious complications following transarterial embolization (TAE) for hepatocellular carcinoma (HCC). However, the exact incidence and the necessity of antibiotic prophylaxis remain undetermined. Between November 1996 and November 1997, we prospectively studied bacterial infections in 231 HCC patients who underwent 287 angiographic procedures without antibiotic prophylaxis, including 176 TAEs and 111 hepatic arteriographies (HAs). Four of the 111 HAs were complicated by transient asymptomatic bacteremia. Of the 176 TAEs, 2 were associated with asymptomatic bacteremia, and 7 (4%) were associated with symptomatic bacterial infection, including 3 cases of sepsis, 2 of liver abscess, and 2 of infected biloma. For patients with HCC, TAE was associated with a higher risk of developing symptomatic bacterial infections than was HA (4% vs. 0, respectively; P = .03). Previous gastrectomy was the only possible risk factor for liver abscess. Finally, early diagnosis and treatment of these infectious complications usually result in successful outcome.

Decreased diversity of hepatitis C virus quasispecies during bone marrow transplantation

To elucidate the role of host immune status in the evolution and complexity of hepatitis C virus (HCV) quasispecies, three chronic HCV-infected patients who underwent bone marrow transplantation (BMT) were studied. The three transplanted patients' sera were sampled at pre-BMT, 3 months after BMT, and 12 months after BMT and the nucleotide diversity and substitution of the hypervariable region (HVR) of HCV quasispecies were analyzed. The nucleotide diversity was high at the pre-BMT period (28.2-43.4 x 10(-2) nucleotide difference/site). HVR of HCV quasispecies then became homogeneous in the first 3 months after BMT (0.11-6.40 x 10(-2) nucleotide difference/site). The nucleotide diversity of HVR at 12 months after BMT of all three patients was higher than that of 3 months after BMT but still lower than that of pre-BMT (2.09-6.40 x 10(-2) nucleotide difference/site). The analysis on nucleotide substitution rate showed a higher value between pre-BMT and 3 months after BMT (0.624-0.708 nucleotide difference/site per year) than that between 3 months and 12 months after BMT (0.072-0.127 nucleotide difference/site per year). HCV RNA titer decreased when the host had a low white cell count and increased accordingly. It was concluded that the evolution of HVR of HCV quasispecies related to the immune status of the host during BMT: after immunosuppression, an initial increase of viral populations was followed by the emergence of a dominant strain while the quasispecies gradually recovered as the immunity of the host gained its competence.

Chromosomal aberrations in nasopharyngeal carcinoma analyzed by comparative genomic hybridization

To investigate the genomic imbalances associated with nasopharyngeal carcinoma (NPC), we have performed chromosome analysis by comparative genomic hybridization (CGH) on 51 tumors, including 25 primary and 26 recurrent tumors. The most common copy number increases occurred on chromosome arms 12p (59%), 1q (47%), 17q (47%), 11q (41%), and 12q (35%). The minimal overlapping regions were at 12p12-13, 1q21-22, 17q21, 17q25, 11q13, and 12q13. The most frequent losses were from chromosome arms 3p (53%), 9p (41%), 13q (41%), 14q (35%), and 11q (29%). The minimal overlapping regions were at 3p12-14, 3p25-26, 9p21-23, 13q21-32, 14q12-21, and 11q14-23. Compared with the primary cancers, no additional chromosomal change was found in the recurrent tumors; however, the most frequent gain in the recurrent NPCs was at 11q13 (53%) instead of 12p in the primary tumors. An increase of gene alterations correlated with clinical stage. Our results provide a first comprehensive view of the genomic changes associated with NPC and reveal several new sites of genomic imbalance, indicating the possible involvement of novel oncogenes/tumor suppressor genes in the carcinogenesis of NPC.

Comparison of two methods for quantification of hepatitis B viral DNA

BACKGROUND

Quantitation of serum hepatitis B virus (HBV) DNA has proven useful in assisting with patient management and treatment and several commercially available assays have been developed to quantify serum HBV-DNA levels.

METHODS

The performance of the cross-linking assay and the branched-DNA signal amplification (bDNA) assay for the quantitative measurement of HBV-DNA was studied in 99 hepatitis B surface antigen-positive and viraemic patients.

RESULTS

Of these samples, 82 (83%) were positive for HBV-DNA by both assays and four (4%) were below the cut-off for both assays. Of the remaining 13 samples, 10 contained measurable levels of HBV-DNA by the cross-linking assay alone and three other samples contained measurable levels of HBV-DNA by the bDNA assay alone. The sensitivity gain of the cross-linking assay relative to bDNA assay in this study population was 10/92 (11%). In addition, a linear regression analysis showed that the HBV-DNA levels obtained from both assays was significantly correlated (gamma=0.974, P< 0.0001).

CONCLUSIONS

These findings suggest that the recently developed cross-linking assay is more sensitive than the bDNA assay for the quantitative determination of HBV-DNA.

C. elegans MAC-1, an essential member of the AAA family of ATPases, can bind CED-4 and prevent cell death

In the nematode Caenorhabditis elegans, CED-4 plays a central role in the regulation of programmed cell death. To identify proteins with essential or pleiotropic activities that might also regulate cell death, we used the yeast two-hybrid system to screen for CED-4-binding proteins. We identified MAC-1, a member of the AAA family of ATPases that is similar to Smallminded of Drosophila. Immunoprecipitation studies confirm that MAC-1 interacts with CED-4, and also with Apaf-1, the mammalian homologue of CED-4. Furthermore, MAC-1 can form a multi-protein complex that also includes CED-3 or CED-9. A MAC-1 transgene under the control of a heat shock promoter prevents some natural cell deaths in C. elegans, and this protection is enhanced in a ced-9(n1950sd)/+ genetic background. We observe a similar effect in mammalian cells, where expression of MAC-1 can prevent CED-4 and CED-3 from inducing apoptosis. Finally, mac-1 is an essential gene, since inactivation by RNA-mediated interference causes worms to arrest early in larval development. This arrest is similar to that observed in Smallminded mutants, but is not related to the ability of MAC-1 to bind CED-4, since it still occurs in ced-3 or ced-4 null mutants. These results suggest that MAC-1 identifies a new class of proteins that are essential for development, and which might regulate cell death in specific circumstances.

Characterization of monoclonal antibodies against hepatitis C virus nonstructural protein 3: different antigenic determinants from human B cells

The nonstructural (NS3) region protein of hepatitis C virus (HCV) possesses major B-cell epitopes that induce antibodies after infection. To elucidate further the characteristics of these B cells and their role in the immune regulation of HCV infection, T9 (portion of NS3 region, amino acids [a.a.] 1188-1493)-specific monoclonal antibodies were derived and mapped for B-cell antigenic determinants with recombinant proteins. A total of 10 T9-specific hybridomas were generated and tested for B-cell antigenic determinants. To analyze the B-cell antigenic determinants, eight recombinant proteins including NS3-e (a.a. 1175-1334), NS3-a' (a.a. 1175-1250), NS3-a (a.a. 1251-1334), NS3-b (a.a. 1323-1412), NS3-c (a.a. 1407-1499), NS3-a/b (a.a. 1251-1412), NS3-bc (a.a. 1323-1499), and NS3-abc (a.a. 1251-1499) encoded by NS3-region internal clones were expressed and tested for immunoblotting. The data suggested IgG hybridomas recognized NS3-a, NS3-a', or NS3-b protein by immunoblotting. By contrast, the NS3-e protein bears the major antigenic determinant recognized by human sera. Half of the hybridomas were found to react with protein NS3-a', which is not a major B-cell antigenic determinant in humans. These data suggested that conformational epitopes in vivo may be important for B-cell recognition.

Minimal role of GB virus-C/hepatitis G virus in fulminant and subfulminant hepatitis in Taiwan

BACKGROUND

The role of GB virus-C/hepatitis G virus (GBV-C/HGV) in fulminant hepatitis (FH) and subfulminant hepatitis (SFH) remains unclear.

METHODS

Thirty-two FH or SFH patients, with adequate clinical information and serum specimens, were studied. Serum samples were tested for hepatitis markers and genomes of hepatitis A-E viruses, as well as GBV-C/HGV.

RESULTS

Of the cases of FH/SFH studied, one (3%) was caused by anti-tuberculosis agents, 26 (81%) had hepatotropic virus infection, and five (16%) had no identifiable cause. Of the 26 patients with hepatotropic virus infection, five had acute hepatitis B infection (one with acute hepatitis D virus (HDV) co-infection), one had acute hepatitis C infection, 16 were hepatitis B surface antigen carriers with reactivation or superimposed by unidentified agent(s) (two had triple virus infections), three were hepatitis B carriers with HDV superinfection, and one had GBV-C/HGV infection in addition to exposure to halothane. GBV-C/HGV-RNA was detected in only three of 32 patients (9%) and all had a history of blood transfusion or co-existing causative factors. Of the 26 patients with hepatotropic virus infection, 18 were tested for antibodies against GBV-C/HGV envelope protein and seven were reactive, suggesting past infection.

CONCLUSIONS

The role of GBV-C/HGV in causing FH and SFH is minimal in Taiwan and HBV infection remains the major aetiology. These findings also suggest the existence of as yet unrecognized agents, responsible for such catastrophic illnesses.

Opportunistic hepatic infections in AIDS patients with fever of unknown origin

The clinical features and histopathologic manifestations of hepatic opportunistic infections in patients with acquired immunodeficiency syndrome (AIDS) in Taiwan remain unexplored. We report 28 AIDS patients (25 men, 3 women; mean age, 34 years) with fever of unknown origin who underwent 31 liver biopsies from December 1995 to May 1997. In most cases, the biochemical tests showed moderate to markedly elevated alkaline phosphatase concentrations, but normal or mildly elevated aminotransferase concentrations. The most common histopathologic finding was macrosteatosis, which was noted in 15 of the 28 patients. Another important histopathologic finding indicating the etiology of hepatic opportunistic infection was granuloma, which was found in 11 patients. Histochemical stain and culture of liver specimens yielded Mycobacterium avium complex (MAC) in eight patients, Mycobacterium tuberculosis in two patients, Histoplasma capsulatum in one patient, and cytomegalovirus in one patient with concomitant MAC infection. Therefore, a definitive diagnosis in AIDS patients with fever of unknown origin was made in 11 of the 28 cases with the assistance of liver biopsy. During follow-up, late extrahepatic involvement by the same infectious agents was found in six patients. Thus, hepatic manifestations could be a harbinger of disseminated opportunistic infections in AIDS patients.