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Biomedical subjects

Yoshihiko Yano

Publications and source records attributed to Yoshihiko Yano.

At least 19 recordsLinked to original sources

Genotype and variations in core promoter and pre-core regions are related to progression of disease in HBV-infected patients from Northern Vietnam.

Vietnam is one of the countries with a high rate of hepatitis B virus (HBV) infection, but there are only a few reports about relation of HBV genotypes and mutations to clinical course in Northern Vietnam. The characteristics of HBV and its relationship to clinical outcome in patients from Northern Vietnam were analyzed. Serum samples were collected from 183 HBV-infected Vietnamese patients. They were clinically categorized into 4 groups: hepatocellular carcinoma (HCC), liver cirrhosis (LC), chronic hepatitis (CH), and asymptomatic carriers (ASC). HBV serology, alpha-fetoprotein, HBV genotypes, HBV-DNA level and mutations in the core promoter and pre-core regions of HBV-DNA were examined. The majority of sera contained HBV genotype B (67.8%) and C (27.9%). The median age was matched between genotype B and C (38.2 vs. 42.9 years). The rates of HBeAg seroconversion and G1896A for genotype B were significantly higher than those for genotype C (P<0.05). Genotype C had a higher HBV-DNA level than genotype B. C1858 was frequent, especially in genotype C (62.7%). The most prevalent genotype in ASC and CH was genotype B. The presence of the mutation A1762T/G1764A correlated with disease progression. The triple mutation T1753C/A1762T/ G1764A was quite common and was more prevalent in LC and HCC than in CH and ASC. In Northern Vietnamese, HBV genotypes B and C were prevalent. Genotype C and mutations in the core promoter region were associated with progressive, severe liver diseases.

Adolescent↗

The LXXLL motif of murine forkhead transcription factor FoxO1 mediates Sirt1-dependent transcriptional activity.

The forkhead transcription factor FoxO1 has been identified as a negative regulator of insulin/IGF-1 signaling. Its function is inhibited by phosphorylation and nuclear exclusion through a PI3K-dependent pathway. However, the structure/function relationship of FoxO1 has not been elucidated completely. In this study, we carried out mutation analysis of the FoxO1 coactivator-interacting LXXLL motif (amino acids 459-463). Expression of a 3A/LXXAA mutant, in which 3 Akt phosphorylation sites (T24, S253, and S316) and 2 leucine residues in the LXXLL motif (L462 and L463) were replaced by alanine, decreased both Igfbp-1 and G6Pase promoter activity and endogenous Igfbp-1 and G6Pase gene expression in simian virus 40-transformed (SV40-transformed) hepatocytes. Importantly, mutagenesis of the LXXLL motif eliminated FoxO1 interaction with the nicotinamide adenine dinucleotide-dependent (NAD-dependent) deacetylase sirtuin 1 (Sirt1), sustained the acetylated state of FoxO1, and made FoxO1 nicotinamide and resveratrol insensitive, supporting a role for this motif in Sirt1 binding. Furthermore, intravenous administration of adenovirus encoding 3A/LXXAA FoxO1 into Lepr db/db mice decreased fasting blood glucose levels and improved glucose tolerance and was accompanied by reduced G6Pase and Igfbp-1 gene expression and increased hepatic glycogen content. In conclusion, the LXXLL motif of FoxO1 may have an important role for its transcriptional activity and Sirt1 binding and should be a target site for regulation of gene expression of FoxO1 target genes and glucose metabolism in vivo.

1-Methyl-3-isobutylxanthine↗

Expression of thioredoxin and thioredoxin-binding protein-2 in the liver of patients with chronic hepatitis C as a predictor of response to interferon therapy.

Oxidative stress contributes to the pathogenesis of various hepatic injuries. Thioredoxin (TRX) is an indicator of oxidative stress, reported to be increased in the serum of patients with chronic hepatitis C with the progression of fibrosis. The aim of this study was to evaluate the clinical significance of the expression of TRX and thioredoxin-binding protein-2 (TBP-2), which is a negative regulator of TRX function, in the liver of patients with chronic hepatitis C and the relationship of this to the efficacy of interferon (IFN) treatment. A retrospective study was performed using the liver biopsy specimens obtained before IFN treatment from 69 patients with chronic serotype 1 hepatitis C virus (HCV) infection. TRX and TBP-2 mRNA levels in the liver biopsy specimens were amplified by real-time RT-PCR. The serum TRX protein level was estimated with a sandwich enzyme-linked immunosorbent assay kit, and the expression of TRX protein in the liver was examined immunohistochemically in 19 patients. There was no association between the serum TRX level and the TRX level in the liver. There was a significant correlation between the expression level of TRX protein in the liver and the TRX mRNA level in the liver. TRX and TBP-2 levels in the liver tended to decrease slightly with increased fibrosis stage, although not significantly. The TRX level in the liver tended to increase with hepatitis activity index, although not significantly. TBP-2 mRNA levels in the liver were significantly higher in responders than non-responders to the IFN therapy (p<0.05). Among patients who had a high viral load of >850 KIU/ml, the TRX level in the livers of non-responders was significantly lower than that in the livers of responders (p<0.05). TRX and TBP-2 mRNA levels in the liver before IFN therapy may predict the outcome of IFN therapy in patients with chronic serotype 1 HCV infection.

Adult↗

Binding of HTm4 to cyclin-dependent kinase (Cdk)-associated phosphatase (KAP).Cdk2.cyclin A complex enhances the phosphatase activity of KAP, dissociates cyclin A, and facilitates KAP dephosphorylation of Cdk2.

Cyclin-dependent kinase 2 (cdk2) activation requires phosphorylation of Thr160 and dissociation from cyclin A. The T-loop of cdk2 contains a regulatory phosphorylation site at Thr160. An interaction between cdc-associated phosphatase (KAP) and cdk2 compromises the interaction between cdk2 and cyclin A, which permits access of KAP, a Thr160-directed phosphatase, to its substrate, cdk2. We have reported that KAP is bound and activated by a nuclear membrane protein, HTm4. Here, we present in vitro data showing the direct interaction between the HTm4 C terminus and KAP Tyr141. We show that this interaction not only facilitates access of KAP to Thr160 and accelerates KAP kinetics, but also forces exclusion of cyclin A from the KAP.cdk2 complex.

Amino Acid Sequence↗

The cell cycle associated protein, HTm4, is expressed in differentiating cells of the hematopoietic and central nervous system in mice.

HTm4 is a member of a newly defined family of human and murine proteins, the MS4 (membrane-spanning four) protein group, which has a distinctive four-transmembrane structure. MS4 protein functions include roles as cell surface signaling receptors and intracellular adapter proteins. We have previously demonstrated that HTm4 regulates the function of the KAP phosphatase, a key regulator of cell cycle progression. In humans, the expression of HTm4 is largely restricted to cells of the hematopoietic lineage, possibly reflecting a causal role for this molecule in differentiation/proliferation of hematopoietic lineage cells. In this study, we show that, like the human homologue, murine HTm4 is also predominantly a hematopoietic protein with distinctive expression patterns in developing murine embryos and in adult animals. In addition, we observed that murine HTm4 is highly expressed in the developing and adult murine nervous system, suggesting a previously unrecognized role in central and peripheral nervous system development.

Amino Acid Sequence↗

Serum hepatitis B virus DNA levels differentiating inactive carriers from patients with chronic hepatitis B.

OBJECTIVE: We compared serum hepatitis B virus (HBV)-DNA levels in different states of hepatitis B infection, and investigated whether there is an HBV-DNA value that can be used for differentiating inactive carriers from patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis. METHODS: A retrospective study using sera at a followed endpoint from 64 Japanese patients with chronic HBV infection seen in Kobe University Hospital between 1989 and 2002. Sera of patients were assayed using a polymerase chain reaction-based assay. RESULTS: Genotype C was dominant (95.4%). Patients with chronic hepatitis with an elevation of the serum alanine aminotransferase (ALT) level had significantly higher HBV-DNA levels than patients with persistently normal ALT. For one time observation at a followed endpoint, the mean HBV-DNA level of HBeAg-negative inactive carriers was significantly lower than that of HBeAg-negative chronic hepatitis patients (3.6+/-1.0 versus 4.8+/-1.5 log copies/ml, P<0.005). The use of a cutoff value of 4.5 or 5.0 log copies/ml misclassified 23 and 18% of HBeAg-negative inactive carriers and 50 and 55% of patients with HBeAg-negative chronic hepatitis. If testing were performed on two occasions with approximately a 4-month interval, the cutoff values of 4.5 and 5.0 log copies/ml would misclassify 20 and 10% of HBeAg-negative inactive carriers and 28.6 and 28.6% of patients with HBeAg-negative chronic hepatitis. CONCLUSIONS: The measurement of serum HBV DNA more than twice is useful for assessing chronic hepatitis B surface antigen carriers and confirms that 10 copies/ml may be an appropriate level of HBV for characterizing the inactive carrier state.

Adult↗

Multiple hypervascular liver nodules in a heavy drinker of alcohol.

A case of hypervascular nodules in the liver, but without hepatitis B or C virus infection in a 38-year-old woman with a history of alcohol abuse is presented. An ultrasound disclosed 1-2-cm hypoechoic tumors in the right and left lobes. Magnetic resonance imaging showed high-intensity tumors at both the T1-weighted and T2-weighted sequences. Incremental dynamic computed tomography and hepatic angiography revealed hypervascular tumors. Ultrasound-guided needle biopsy revealed no evidence of hepatocellular carcinoma, metastatic liver cancer, hemangioendothelioma, inflammatory pseudotumors or pseudolymphoma, but demonstrated stellate-scar fibrosis septa, which contained small unpaired arteries without hyperplasia dividing the nodule. Moreover, marked pericellular fibrosis, neutrophilic infiltration and Mallory bodies were observed in the cytoplasm. There was no evidence of bile duct proliferation. From these findings, the diagnosis of alcohol-induced fibrosis, distinctly different from focal nodular hyperplasia, was tenable. Further studies may provide insights into the pathogenesis of nodule formation and hypervascularity in heavy drinkers of alcohol.

Adult↗

Long-term follow-up of Japanese patients with chronic hepatitis B treated with interferon-alpha.

The long-term usefulness of interferon-alpha (IFN-alpha) in chronic hepatitis B remains controversial. To investigate the long-term efficacy of IFN-alpha therapy in chronic hepatitis B, 62 Japanese patients, including 27 patients treated with IFN-alpha (IFN group) and 35 patients without antiviral therapy matched by age and sex as controls (control group), were followed up for 2-14 years. At entry, the serum alanine aminotransferase (ALT) level in the IFN group was significantly higher than that in the control group (238.6+/-250.1 vs. 142.3+/-152.1 IU/l, P < 0.05). The prevalence of genotype C was 89%, with no difference between the two groups (93 vs. 86%). There was no significant difference in the presence of the precore mutation or the dual core promoter mutations between the IFN and control groups (37 vs. 46%, 74 vs. 66%). After long-term follow-up, the rate of sustained HBeAg seroconversion was comparable in the two groups (33 vs. 31%). Normalization of serum ALT level was seen in 44% of the IFN group and 51% of the control group, with no difference. There was also no difference in the percentage of cases with loss of serum HBV-DNA by PCR assay between the two groups (33 vs. 29%). During follow-up, two patients of the control group and three patients of the IFN group developed cirrhosis, and one of the IFN- treated patients progressed to hepatocellular carcinoma. The results of this long-term follow-up study showed that no benefit of IFN-alpha treatment was detectable during long-term follow-up in Japanese patients with chronic hepatitis B.

Adult↗

Expression and localization of ecto-nucleotide pyrophosphatase/phosphodiesterase I-1 (E-NPP1/PC-1) and -3 (E-NPP3/CD203c/PD-Ibeta/B10/gp130(RB13-6)) in inflammatory and neoplastic bile duct diseases.

Ecto-nucleotide pyrophosphatase/phosphodiesterase-I enzyme (E-NPP) consists of three closely related molecules: E-NPP1, E-NPP2 and E-NPP3. We investigated the expression and localization of E-NPP1 and -3 in human inflammatory and neoplastic bile duct diseases. Immunohistochemically E-NPP1 was located on the apical cytoplasmic side of cancer cells, whereas E-NPP3 was located in the apical plasma membrane. Western blot analysis revealed that the expression of E-NPP3, but not E-NPP1, was higher in tumor tissues than in surrounding tissues and the specific form of the E-NPP3 protein was readily detected in the sera of bile duct carcinoma (BDC) patients. Furthermore, it was confirmed that E-NPP3 was associated with migration ability by using of NIH3T3 cells that stably transfected with E-NPP3 cDNA. These results suggest that E-NPP3 is involved in the infiltration of neoplastic BDC and is possible to be a tumor marker.

Animals↗

Apoptotic pathway related to oval cell proliferation.

BACKGROUND AND AIM: Oval cells, liver stem cell-derived cells, are generated from the liver periportal region and spread into the parenchyma by an autocrine signaling pathway. The mechanism behind how oval cells take their place among packed silent hepatocytes, however, is not well understood. We hypothesized that apoptosis involves a decrease in hepatocytes surrounding oval cells. METHODS: Male Fisher rats were treated using the AAF/PH protocol to induce oval cells in the liver. Apoptosis was assessed by measuring the activity of caspase-3, -8 and -9, and apoptosis-related molecules such as caspase-3, Fas, Fas-L and Bax were also assessed by immunohistochemical analysis and reverse transcriptase-polymerase chain reaction (RT-PCR). Apoptosis was confirmed by TUNEL staining. Regarding antiapoptotic factors, nuclear factor-kappaB (NF-kappaB) DNA binding activity and proliferating cell nuclear antigen (PCNA) expression were examined. RESULTS: NF-kappaB elevated at the early stage of oval cell proliferation. Conversely, caspase activity increased after NF-kappaB elevation. The mRNA of caspase-3, Fas, Fas-L and Bax was induced during and after AAF/PH treatment. Immunohistochemically, oval cells lacked the expression of these proteins, whereas the hepatocytes, particularly those surrounding oval cells, expressed strongly. CONCLUSIONS: The present study suggests that the apoptosis in hepatocytes through both extrinsic and intrinsic pathways mediates oval cell proliferation.

Animals↗

Early response to interferon alpha treatment and long-term clinical outcome in Japanese patients with chronic HBV genotype C infection.

Genotype C of hepatitis B virus (HBV) has been shown to be associated with a poor clinical outcome and less favorable response to interferon (IFN) alpha therapy compared to genotype B. We evaluated the response to IFN alpha therapy and long-term clinical outcome in Japanese patients with chronic active HBV genotype C infection. Thirty Japanese patients with chronic active hepatitis who received natural IFN alpha therapy were followed for 2-12 years (mean 5.9 years). Twenty-four patients were treated short-term (daily for 4 weeks at a mean total dosage of 174 million units) and 6 patients were treated long-term (total of 26 weeks at a mean total dosage of 687 million units). Twelve of 30 (40%) patients had an antiviral response at 6 months after therapy. Clinical data before treatment in both responders and non-responders were comparable. Although not significant, responders tended to have younger age, a higher serum transaminase level, a lower frequency of precore mutation (G1896A) (67% vs. 92%) and a higher frequency of core promoter mutation (A1762T/G1764A) (89% vs. 58%) than non-responders. The patients treated long-term responded significantly better than those treated short-term (83% vs. 29%, P=0.026). Up to 12 years after therapy, a higher percentage of responders than non-responders had sustained clearance of HBeAg with seroconversion and normalization of transaminase concentration at the followed end point (83% vs. 17%, P<0.001). Two non-responder patients had cirrhosis after long-term follow-up. One non-responder patient died of hepatocellular carcinoma 8 years after IFN therapy; except in this patient there was no development of decompensated cirrhosis. Early responsiveness to IFN alpha therapy in Japanese patients with chronic active HBV genotype C infection improves the long-term clinical outcome.

Adult↗

IFN-alpha prevents the growth of pre-neoplastic lesions and inhibits the development of hepatocellular carcinoma in the rat.

Interferon (IFN)-alpha treatment is a common therapy for chronic viral hepatitis and contributes to preventing hepatocarcinogenesis. However, it is not clear whether IFN-alpha directly inhibits the clonal expansion of pre-neoplastic hepatocytes. To clarify the mechanism by which IFN-alpha prevents hepatocarcinogenesis, we examined the effect of IFN-alpha in a chemically induced hepatocarcinogenesis model initiated by diethylnitrosamine (DEN) and promoted by 2-acetylaminofluorene (2-AAF) and partial hepatectomy, in which hepatocellular carcinoma (HCC) arises through pre-neoplastic foci without inflammation or fibrosis. The protocols of IFN-alpha administration were started simultaneously with chemical initiation and lasted for either 4 or 40 weeks. The pre-neoplastic foci and neoplastic HCC were evaluated at 4 or 40 weeks after chemical initiation, respectively. The effects of IFN-alpha were assessed by the expression of tumor-related genes and cell cycle-related genes in the pre-neoplastic foci, using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). As a result of IFN-alpha treatment, the numbers and average volume of pre-neoplastic foci were reduced. The proliferating cell nuclear antigen index and the expression of G(1) cyclins were also reduced in the pre-neoplastic foci in the IFN-treated group. The expression of p21, which is an inhibitor of cyclin-kinase complexes was higher in the foci of the IFN-treated group, while p53 expression was not altered in this group, compared with the control group. IFN-alpha also suppressed the tumor development at 40 weeks after initiation. And in the long-term IFN-alpha-treated group, both the tumor numbers and average tumor size were markedly more reduced than those in the short-term-treated group. Therefore, it was demonstrated that longer treatment with IFN-alpha was more effective, compared with shorter treatment. In conclusion, it was shown that IFN-alpha directly prevented and delayed hepatocarcinogenesis through the suppression of pre-neoplastic cell proliferation and that it may partially depend on p21 induction through a p53-independent pathway.

Animals↗

Hepatitis B virus DNA in anti-HBe-positive asymptomatic carriers.

OBJECTIVES: We examined the level of hepatitis B virus (HBV) DNA and the mutations in the precore, core and polymerase regions of HBV in sera from anti-HBe-positive asymptomatic carriers (ASC). METHODS: The amount of HBV DNA was determined semiquantitatively by mutation site-specific assay in sera from 19 anti-HBe-positive ASC and 31 HBeAg-positive patients with chronic liver disease (CLD). The mutations in the precore, core and polymerase (terminal protein) regions, spanning 1,037 nucleotides, of HBV in sera from three cases each of anti-HBe-positive ASC, HBeAg-positive ASC and HBeAg-positive CLD were examined by directly sequencing the amplified HBV DNA. RESULTS: The level of HBV viremia in anti-HBe-positive ASC was significantly lower than that in HBeAg-positive CLD patients (p < 0.01). By sequence analysis, there were a few missense mutations detected in HBeAg-positive ASC and HBeAg-positive CLD patients. In contrast, many mutations, especially in the central or N-terminal half of the core region and N-terminal part of the polymerase region, were detected in anti-HBe-positive ASC. CONCLUSION: Mutations not only in the precore/core region, but also in the polymerase region of HBV might cause damage to some important functions for efficient replication of HBV and be involved in the reduced amount of HBV in anti-HBe-positive ASC.

Adult↗

Retarded eruption of maxillary second premolars associated with late development of the germs.

This study focused on five unusual cases with anomalous eruptions of the maxillary second premolars that related to late development of the germs. In four cases, the affected premolars erupted between the ages of 12y3m and 14y6m. In one case, which was suspected to include bilateral anomalies, the eruption of the premolar was excessively late, continuing up to 17y8m old. It was surmised that the degree of tooth formation in the contralateral side might help to predict approximately at what age the late premolars will erupt.

Adolescent↗

Different apoptotic regulation of TRAIL-caspase pathway in HBV- and HCV-related hepatocellular carcinoma.

Human hepatocellular carcinoma (HCC) appears to be strongly associated with apoptosis and its breakdown may be involved in the occurrence of HCC. Like the Fas/Fas-L system, the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) transduces apoptosis in a number of cancers; it is also a clinical candidate for cancer therapy. To examine its applicability in future therapy, the apoptotic pathway through TRAIL was investigated in HBV- and HCV-related HCC that have different mechanisms of hepatocarcinogenesis. Caspase-3 activity and the expression of four types of TRAIL receptor mRNAs were quantitated in tumor and contiguous non-tumor tissues obtained from 27 patients with HCC (HBV-related in 10; HCV-related in 17). The expression of caspase-3 and TRAIL receptors was also examined immunohistochemically. A significantly positive correlation was observed between caspase-3 activity and TRAIL-R1, -R2. Caspase-3 activity and TRAIL-R1, -R2 expression in tumor tissue were significantly lower than those in non-tumor tissue in HBV-related HCC. Some HCV-related HCC cases, however, demonstrated elevated caspase-3 activity and TRAIL-R1, -R2 expression in tumor tissue. HBV-related HCC demonstrated significantly suppressed caspase-3 activity, signifying apoptosis. Both TRAIL-R1 and -R2 showed coefficient correlation with caspase-3 activity, and were strongly associated with apoptosis in human HCC.

Apoptosis↗

A case of well-differentiated hepatocellular carcinoma arising in primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is a chronic progressive, autoimmune liver disease that increases the risk of hepatobiliary malignancies at a late stage. We report a 66-year-old woman with PBC combined with hepatocellular carcinoma (HCC) accompanied by hypoglycemia. Two large tumors were detected on admission and the patient died because of tumor rupture and subsequent liver failure. Histological analysis revealed well-differentiated HCC in both of the tumors. Sometimes the patient had suffered from hypoglycemic attacks of unknown origin, but serum immunoreactive insulin (IRI) was within the normal range. It was interesting that such large well-differentiated hepatocellular carcinomas were generated in PBC.

Aged↗

Expression and localization of ecto-nucleotide pyrophosphatase/phosphodiesterase I-3 (E-NPP3/CD203c/PD-I beta/B10/gp130RB13-6) in human colon carcinoma.

Ecto-nucleotide pyrophosphatase/phospho-diesterase-I enzyme (E-NPP), one of the type II transmembrane proteins, cleaves phosphodiester and phosphosulfate bonds of a variety of substrates including deoxynucleotides, NAD, and nucleotide sugars. Mammalian E-NPP consists of three closely related family proteins; E-NPP1 (PC-1), E-NPP2 (PDNP2/PD-Ialpha/autotaxin), and E-NPP3 (CD203c/PDNP3/PD-Ibeta/B10/gp130RB13-6) that express in different cells or at different locations even in the same cell. E-NPP3 is associated with malignant subversion and invasive properties. In this study, the expression and localization of E-NPP3 were investigated in human colon carcinoma. Western blotting showed strong E-NPP3 expression in cancer tissues and in the serum of colon carcinoma patients. Immunohistochemically, E-NPP3 was expressed not only in the apical but also in the basolateral plasma membranes of cancer cells. No prominent pattern of intracellular localization, and no relation between clinical stage and E-NPP3 expression were observed. Our results suggested that E-NPP3 is associated with carcinogenesis of human colon cancer and that serum E-NPP3 might be a tumor marker of colon carcinoma.

Colonic Neoplasms↗

Development of multicentric hepatocellular carcinoma after completion of interferon therapy.

We report a case of multicentric hepatocellular carcinoma that developed in a 74-year-old man 3 and 6 years after interferon (IFN) treatment for chronic hepatitis C, despite sustained virologic, biochemical, and histological improvement. Initially, serum hepatitis C virus RNA was positive and the patients' serum level of alanine aminotransferase (ALT; 82 IU/ml) was abnormal. Hepatitis B virus (HBV) in the serum was negative for surface antigen, surface antibody, core antibody, and DNA. The patient was started on 10 x 10(6) international units (IU) of IFNalpha, 3 days a week for a total of 24 weeks. After the IFN therapy, the patient demonstrated a normal serum ALT level, and was continuously negative for HCV-RNA, and histology improved from chronic active hepatitis to chronic persistent hepatitis. Follow-up studies with ultrasonography (US) every 3 months and computed tomography (CT) every 6 months revealed no space-occupying lesion (SOL) for 3 years after IFN treatment.US-guided biopsies of two 15-mm hypoechoic SOLs in segments eight (S8) and seven (S7) 34 and 74 months, respectively, after IFN treatment showed well-differentiated hepatocellular carcinoma (HCC). Clinical data, imaging studies, and histologic examinations showed that both tumors were multicentric HCC. Further studies may provide insights into the possible role of HCV in hepatocarcinogenesis in patients demonstrating HCV eradication by IFN treatment.

Aged↗