Full-length sequences of subgenotype IIIA and IIIB hepatitis A virus isolates: characterization of genotype III HAV genomes.

To elucidate the extent of genomic heterogeneity of human hepatitis A virus (HAV) strains and to characterize genotype III HAV strains over the entire genome, the full-length sequence of three subgenotype IIIA isolates (HA-JNG04-90F, HA-JNG08-92F, and HAJ95-8F) and one IIIB isolate (HAJ85-1F) was determined. The HA-JNG04-90F, HA-JNG08-92F, and HAJ95-8F genomes which comprised 7463 or 7464 nt excluding the poly(A) tail, were closest to a reported nearly entire sequence of a IIIA isolate (NOR-21) with identities of 94.4-97.8% over the entire ORF sequence, and the HAJ85-1 genome (7462 nt) to HA-JNG06-90F of IIIB with an identity of 98.6%. The phylogenetic trees constructed based on the complete ORF sequence or the 168-nt VP1/2A junction sequence and comparative analysis with reported HAV isolates suggested the presence of three distinct clusters within IIIA represented by HA-JNG04-90F, HA-JNG08-92F, and HAJ95-8F. The extreme 5' end sequences of IIIA and IIIB were well-conserved, beginning with the sequence UUCAAGAGGG. A single base deletion of G at nt 20, which is involved in the formation of a small loop in domain I, was characteristic of both IIIA and IIIB. Conserved and divergent amino acid sequences as well as amino acids unique to genotype III, IIIA or IIIB were recognized.

Analysis of the full-length genome of a subgenotype IIIB hepatitis A virus isolate: primers for broadly reactive PCR and genotypic analysis.

Among six known subgenotypes (IA, IB, IIA, IIB, IIIA, and IIIB) of human hepatitis A virus (HAV), the complete genomic sequence has not been determined for IIIB. In this study, the full-length genomic sequence of a IIIB HAV isolate (HA-JNG06-90F) recovered from a Japanese patient who contracted sporadic hepatitis A in 1990, was determined. The HA-JNG06-90F genome, which comprised 7462 nt excluding the poly(A) tail, was related most closely to NOR-21 of subgenotype IIIA with an identity of 89.1%, and was only 82.6-83.4% similar to human HAV isolates of genotypes I and II over the entire genome. Comparison of full-length genomic sequences of 20 reported isolates and HA-JNG06-90F generated optimal results for separation of different levels: the nucleotide identities were 80.7-86.6% at the genotype level, 89.1-91.9% at the subgenotype level, and 94.6-99.7% at the isolate level. Similar ranges of nucleotide identity were observed when comparing partial nucleotide sequences of the VP1-2B (481 nt; primer sequences at both ends excluded) and 3C/3D (590 nt) regions, which were amplifiable by PCR with primers designed from well-conserved areas of the HAV genome. All 66 samples with IgM-class HAV antibodies tested positive for HAV RNA by both VP1-2B (481 nt)-PCR and 3C/3D (590 nt)-PCR: subgenotype assignment was concordant in all samples tested (IA [n = 61], IB [n = 1], IIIA [n = 2] and IIIB [n = 2]). These results suggest that two broadly reactive PCRs using primers derived from the VP1-2B and 3C/3D regions, respectively, may be applicable to universal detection and phylogenetic analysis of various HAV strains.

Spatial and chronological differences in hepatitis B virus genotypes from patients with acute hepatitis B in Japan.

Genotypes of hepatitis B virus (HBV) were determined in 485 patients with acute hepatitis B from all over Japan. They were A in 92 (19%), Ba in 26 (5%), Bj in 32 (7%), C in 330 (68%) and D in 5 (1%). Sexual contacts were the main route of transmission in them. Overall, HBV persisted in only 5 of the 464 (1%) followed patients. Genotypes C accounted for more than 68% in northern as well as southern areas, contrasting with genotype A accounting for 34% in and around the Metropolitan areas. During 24 years from 1982 to 2005, genotype A increased from 5% to 33%, while genotype B gradually decreased from 26% to 8%. Fulminant hepatitis was significantly more frequent in infection with genotype Bj (41%) than those with the other genotypes (p<0.01). The core-promoter double mutation (T1762/A1764) and precore stop-codon mutation (A1896) were more frequent in patients with fulminant than acute self-limited hepatitis (57% versus 15% and 58% versus 10%, respectively, p<0.01 for both). In conclusion, genotype A distributes unevenly over Japan, prevails in younger patients through sexual transmission and has increased with years. Furthermore, fulminant outcome was more frequent in patients with genotype Bj than those with the other genotypes.

Analysis of prognostic factors in therapeutic responses to interferon in patients with chronic hepatitis C.

The genotype of hepatitis C virus (HCV) and the amount of HCV RNA are often used to predict the efficacy of interferon (IFN) therapy on chronic hepatitis C. In addition to these factors, there may be several factors related to the host. Therefore, the authors undertook a retrospective study in which physical findings and laboratory data before therapy were evaluated by multiple logistic analysis. Two-hundred and five cases with chronic hepatitis C treated with interferon were analyzed in this study. Sustained virological response was observed with 68 cases. Multiple logistic analysis was performed with 29 explanatory variables including HCV genotype, HCV RNA, IFN types, and total dose, along with gender, age, alcohol consumption, body mass index (BMI), histological findings of liver biopsy, platelet counts, and laboratory data of serum enzymes. Analysis on the factors that correlated well with therapeutic efficacy revealed that genotype 2a, 2b showed higher therapeutic responses than genotype 1b with reference to HCV genotypes, and higher IFN dose or lower HCV RNA levels gave better results. With reference to host factors, higher total protein level, lower levels of BMI, total bilirubin, and aspartate aminotransferase were highly correlated with therapeutic efficacy. HCV genotypes and HCV RNA levels have been already identified as prognostic factors. However, the high correlation values of BMI and the total protein level are new findings. It is suggested that probability estimation of therapeutic effects using the logistic regression equation may be a good tool for predicting therapeutic efficacy of IFN therapy on individual cases.

Timing of interferon therapy and sources of infection in patients with acute hepatitis C.

BACKGROUND/AIMS: Controversy over the selection of patients and optimum therapeutic method for acute hepatitis C has continued. The aims of this study were to investigate the source of infection, and to evaluate the timing of interferon (IFN) therapy in patients with acute hepatitis C in Japan. METHODS: The records of 102 patients from 12 facilities in Japan who developed acute hepatitis C after 1990 were investigated. In the patients treated with IFN, we performed multivariate analysis to investigate factors related to sustained virological response (SVR). RESULTS: Medical procedure was the most common source of infection, accounting for 32.4% in the 102 patients (33/102). Of 81 patients treated with IFN, 71 patients were followed after IFN therapy, and 57/71 (80.3%) had SVR. The SVR rate was significantly higher in patients treated with IFN within 24 weeks from onset of symptoms than the SVR rate in those treated after 25 weeks (P=0.0016). Multivariate analysis revealed that only the duration between onset of symptoms and initiation of IFN therapy (within 24 weeks) was related to SVR. CONCLUSIONS: Our multicenter cooperative survey revealed that medical procedure was the most frequent source of infection in acute hepatitis C. As concerns the therapy, interferon treatment should be initiated within 24 weeks after onset of symptoms.

Molecular evolutionary analyses implicate injection treatment for schistosomiasis in the initial hepatitis C epidemics in Japan.

BACKGROUND/AIMS: The mortality due to hepatocellular carcinoma (HCC) has ranged widely in various areas of Japan since 30 years ago and the incidence was particularly high in once Schistosoma japonicum (Sj)-endemic areas. Our aim was to estimate the spread time of hepatitis C virus (HCV) infection in the past with possible relevance to a higher incidence of HCC in once Sj-endemic than Sj-nonendemic areas. METHODS: During 2001, 131 strains of HCV-1b were obtained from patients in three previously Sj-endemic areas, as well as Sj-nonendemic areas in Japan and a cross-sectional study was conducted on them with molecular evolutionary analyses. RESULTS: A phylogenetic tree reconstructed on HCV-1b sequences in the NS5B region disclosed 2 independent clusters for Sj-positive and -negative groups with a high bootstrap value. The estimated effective number of HCV-infections indicated a transition from quiescence to rapid exponential growth in the 1920s among patients with schistosomiasis, which is 20 years earlier than that among patients without schistosomiasis. CONCLUSIONS: The estimated spread time in previously Sj-endemic areas in Japan coincides with injection treatment for Sj since 1921. A high incidence of HCC there would be attributed to a long duration of HCV infection since 1920s.

Fine-tuned high-Q photonic-crystal nanocavity.

A photonic nanocavity with a high Q factor of 100,000 and a modal volume V of 0.71 cubic wavelengths, is demonstrated. According to the cavity design rule that we discovered recently, we further improve a point-defect cavity in a two-dimensional (2D) photonic crystal (PC) slab, where the arrangement of six air holes near the cavity edges is fine-tuned. We demonstrate that the measured Q factor for the designed cavity increases by a factor of 20 relative to that for a cavity without displaced air holes, while the calculated modal volume remains almost constant.

Two-dimensional photonic-crystal-slab channeldrop filter with flat-top response.

We report a theoretical and experimental study of a channel drop filter with two cascaded point-defects between two line-defects in a two-dimensional photonic-crystal slab. Using coupled-mode analysis and a three-dimensional finite-difference time-domain method, we design a filter to engineer the line shape of the drop spectrum. A flat-top and sharp roll-off response is theoretically and experimentally achieved by the designed and fabricated filters. Furthermore, we theoretically demonstrate that drop efficiency is increased dramatically, up to 93%, by introducing hetero-photonic-crystals. We also describe a method to modify the bandwidth of the spectrum.

Domestic infection of hepatitis E in Japan.

In most cases of hepatitis E in Japan, patients acquire the viral infection abroad in countries where hepatitis E is endemic. However, in Nagano Prefecture, Japan, we encountered a patient with hepatitis E who had never been abroad. The diagnosis was made on finding hepatitis E viral RNA and antibodies against the virus in the serum. Prompt normalization of liver function test occurred without medication. The nucleotide sequence of the virus isolated from this patient was closely related to the sequence of previously isolated viruses of genotype III. The source of infection could not be identified.

Epidemiological and clinical study of sporadic acute hepatitis E caused by indigenous strains of hepatitis E virus in Japan compared with acute hepatitis A.

BACKGROUND: We compared acute hepatitis E (AH-E) and acute hepatitis A (AH-A) to investigate the epidemiology, clinical features, and prognosis of AH-E caused by an indigenous hepatitis E virus (HEV) in Japan. METHODS: We enrolled 58 patients diagnosed with AH-A or AH-E (32 men and 26 women; age, 20-72 years) from December 1997 to October 2002. Phylogenetic analysis of the partial 412-nucleotide sequence of open reading frame (ORF) 2 was performed in patients with AH-E. RESULTS: Regarding the geographic distribution of the HEV genotype, genotype III was principally distributed in Honshu Island, and genotype IV in Hokkaido Island ( P = 0.0034). The phylogenetic analysis of the ORF2 region revealed that there were significant geographic differences in the distribution of the HEV strains in Japan, with some strains being widespread and some, localized. In comparison with AH-A patients, those with AH-E were older (56.1 +/- 10.6 vs 45.9 +/- 10.8 years; P = 0.0017). The proportion of males among patients with AH-E was significantly higher ( P = 0.0001). Pyrexia was often observed in AH-A, and malaise in AH-E. Laboratory data indicate that AH-E induces a weak immunological reaction, whereas jaundice appears earlier in AH-E than in AH-A. One patient with AH-E died of acute hepatic failure, but none of those with AH-A died during the study period. CONCLUSIONS: Our results suggest that there are geographical differences between HEV strains in Japan, and that AH-E is more common in males and older patients than AH-A. Laboratory data indicate a weak immunological reaction and early appearance of jaundice in AH-E.

Two subtypes of genotype B (Ba and Bj) of hepatitis B virus in Japan.

We have previously reported 2 subtypes of hepatitis B virus (HBV) genotype B, one of which has the recombination with genotype C over the precore region plus core gene (Ba) and the other of which does not (Bj). A restriction fragment-length polymorphism method with 2 endonucleases was newly developed for distinguishing between subtypes Ba and Bj and was applied to 313 carriers of HBV genotype B in Japan. Subtype Ba was detected in 38 (12%) and subtype Bj in 275 (88%) of the carriers of HBV genotype B. Hepatitis B e antigen in serum was found more frequently in patients with chronic infection with subtype Ba than in those with chronic infection with subtype Bj (8 [32%] of 25 vs. 25 [9%] of 273; P<.01). The new method for distinguishing between Ba and Bj by restriction fragment-length polymorphism would be useful in examining the distribution of these 2 subtypes in situations in which HBV genotype B is prevalent.

High-Q photonic nanocavity in a two-dimensional photonic crystal.

Photonic cavities that strongly confine light are finding applications in many areas of physics and engineering, including coherent electron-photon interactions, ultra-small filters, low-threshold lasers, photonic chips, nonlinear optics and quantum information processing. Critical for these applications is the realization of a cavity with both high quality factor, Q, and small modal volume, V. The ratio Q/V determines the strength of the various cavity interactions, and an ultra-small cavity enables large-scale integration and single-mode operation for a broad range of wavelengths. However, a high-Q cavity of optical wavelength size is difficult to fabricate, as radiation loss increases in inverse proportion to cavity size. With the exception of a few recent theoretical studies, definitive theories and experiments for creating high-Q nanocavities have not been extensively investigated. Here we use a silicon-based two-dimensional photonic-crystal slab to fabricate a nanocavity with Q = 45,000 and V = 7.0 x 10(-14) cm3; the value of Q/V is 10-100 times larger than in previous studies. Underlying this development is the realization that light should be confined gently in order to be confined strongly. Integration with other photonic elements is straightforward, and a large free spectral range of 100 nm has been demonstrated.

Apoptosis-inducing protein derived from hepatocyte selectively induces apoptosis in lymphocytes.

The liver is where lymphocytes undergo activation-induced cell death (AICD) at the resolution phase of an immune response, which is crucial for homeostasis of the immune system and prevention of autoimmunity. Exploring the machinery of AICD in the liver, we found that a primary culture supernatant of murine hepatocytes had an antiproliferative effect on antigen-stimulated T clone and T lymphoma cells. Biological study showed that the antiproliferation was due to induction of apoptosis in a caspase-dependent manner. The apoptosis-inducing potential was sensitive to trypsin, heat (> 70 degrees ) and acid (< pH 5) treatment but could not be neutralized by anti-tumour necrosis factor-alpha, anti-Fas ligand, or anti-transforming growth factor-beta antibodies. Biochemical study of the isolated and purified apoptosis-inducing component from the supernatant showed that it was a protein with a molecular mass of about 68,000-70,000. It induced apoptotic change in murine T and B cells, and to a lesser degree, in human lymphoid cells, but not in macrophages. Biochemical and biological characteristics distinguish this protein from others that have been reported to induce apoptosis of lymphocytes. The identification of an apoptosis-inducing protein derived from murine hepatocytes, which selectively induces apoptosis in lymphocytes, suggests one possible mechanism for immune suppression in the liver.

Persistence of hepatitis B viremia after recovery from acute hepatitis B: correlation between anti-HBc titer and HBV DNA in serum.

During the follow-up of 19 patients with self-limited acute hepatitis B for more than 2 years, clearance of hepatitis B surface antigen from the sera was observed in all patients within 6 months after disease onset, and the corresponding antibody (anti-HBs) appeared in 17 of the 19 patients within 12 months. However, upon performing nested polymerase chain reaction with the estimated sensitivity of 120-200 copies/ml, using two independent pairs of primers derived from the well-conserved sequences in the S gene or C gene region of the hepatitis B virus (HBV) genomes of all seven genotypes, HBV DNA was detected over a period of at least 12 months in serum samples obtained from five (26%) of the 19 patients, although it became undetectable in all five patients at 2-3 years after disease onset. The titer of antibody against hepatitis B core antigen (anti-HBc), assayed by the hemagglutination inhibition (HI, 2(N)) test, was significantly lower at the initial examination in the five patients who remained viremic for at least 12 months, than in the remaining 14 patients who cleared HBV DNA from their sera within 12 months after disease onset (10.6+/-2.7 vs. 13.6+/-0.7, P<0.02). Furthermore, these five patients showed a significantly lower rate of decrease of anti-HBc titer during the 12-month period after disease onset than the remaining 14 patients (55.0+/-32.6 vs. 91.0+/-7.9%, P<0.01). These results indicate that the initial titer and dynamics of anti-HBc may reflect the evolution of HBV viremia after clinical recovery from acute hepatitis B.

Polyphyletic strains of hepatitis E virus are responsible for sporadic cases of acute hepatitis in Japan.

Among 87 patients who were previously treated for acute hepatitis of unknown etiology between 1992 and 2001 at five hospitals in Japan, 11 (13%) patients were positive for immunoglobulin M-class antibodies to hepatitis E virus (HEV) by enzyme immunoassay and had detectable HEV RNA by reverse transcription-PCR with two independent sets of primers derived from well-conserved genomic areas in open reading frames 1 and 2. Clinical HEV infection was significantly associated with male sex (9 of 11 versus 29 of 76 patients [P < 0.01]) and older age (52 +/- 11 [mean +/- standard deviation] versus 41 +/- 17 years [P < 0.05]), and its prevalence differed by geographic region (6 to 25%), with a higher rate in the northern part of Japan. At admission, the 11 patients with HEV-associated hepatitis had elevated alanine aminotransferase levels of 914 to 4,850 IU/liter, and all but 1 had elevated bilirubin levels of 1.5 to 24.0 mg/dl. The 11 HEV isolates were of genotype III or IV and were segregated into three groups with intergroup nucleotide differences of 9.5 to 22.0%. Phylogenetic analysis revealed that four isolates of genotype III were closely related to a Japanese isolate, while the other four isolates of the same genotype were nearest those from the United States. The remaining three isolates were close to known isolates of genotype IV in China and Taiwan but shared less than 88% identity with them. These results indicate that multiple genotypes of HEV cocirculate in Japan and contribute to the development of sporadic acute hepatitis, with the prevalence differing by age, sex, and geographic region.

Demographic, clinical, and virological characteristics of hepatocellular carcinoma in Asia: survey of 414 patients from four countries.

Demographic, etiological, clinical characteristics and treatment of hepatocellular carcinoma (HCC) were surveyed in 414 patients in Asia, including 107 from China, 15 from India, 101 from Indonesia and 191 from Japan. Males predominated in all countries, accounting for up to 75%. The mean +/- SD age at the development of HCC was about 10 years older for the patients from Japan (63.8 +/- 9.5, P < 0.001) and India (63.1 +/- 11.2, P < 0.05) than those from China (54.0 +/- 13.7) and Indonesia (53.7 +/- 14.2). Hepatitis B surface antigen (HBsAg) in serum was detected in 67% of patients from China who were tested, 27% from India, 21% from Indonesia and 18% from Japan, whereas antibody to hepatitis C virus was detected in 4%, 53%, 40% and 70%, respectively; co-occurrence of hepatitis B and C infections was seen only in 7%, 0%, 2%, and 1%, leaving an etiology other than hepatitis viruses in 22%, 20%, 36% and 11%. HCC was diagnosed primarily by ultrasonography in China (43%) and Japan (52%), and on physical examination in India (60%) and Indonesia (52%). The size of the largest tumor exceeded 5.0 cm in diameter only in 24% of the patients from Japan, much less often than in 67%, 87%, and 71%, respectively, of those from China, India and Indonesia (P < 0.001). The most favored treatment was chemolipidolization in China (81%) and Japan (81%), whereas it was transarterial embolization in India (13%) and Indonesia (26%). These results highlight common as well as distinct characteristics of HCC in Asia, and warrant the need for close cooperation toward early diagnosis and effective treatment of HCC.