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E Mita

Publications and source records attributed to E Mita.

At least 19 recordsLinked to original sources
PubMed2001

Significance of serum soluble Fas antigen level in chronic hepatitis C patients treated with interferon: relationship to the therapeutic response.

BACKGROUND AND AIM: Fas system-mediated cytotoxicity is thought to be involved in the development of liver injury in hepatitis C virus (HCV) infection. In this study, we investigated serum soluble Fas antigen levels in chronic hepatitis C patients treated with interferon and their correlation with the therapeutic response. METHODS: The subjects were 67 chronic hepatitis C patients who underwent a 24-week course of alpha-interferon therapy. Patients were categorized into three groups; sustained responders (n = 22), transient responders (n = 24), and non-responders (n = 21), according to changes in the serum alanine aminotransferase level during and after therapy. The viral genotype, viremic level and diversity in the hypervariable region were examined before therapy. Serum soluble Fas antigen levels were assayed by using serum samples taken at the beginning and the end of therapy. RESULTS: In the univariate analysis, serum soluble Fas antigen levels tended to be higher in non-responders (10.0 +/- 3.4 ng/mL) than in sustained responders (8.5 +/- 3.0 ng/mL) and transient responders (8.2 +/- 2.1 ng/mL; P = 0.13 and P < 0.05). The non-response to therapy was observed in eight of the 15 (53%) patients with serum soluble Fas antigen > or = 11 ng/mL, compared with 13 of the 52 (25%) patients with serum soluble Fas antigen < 11 ng/mL (P < 0.05). As for the multivariate analysis, the only significant factor contributing to the sustained response was a low HCV viremic level (P = 0.0046). Significant factors contributing to the non-response were a high serum alanine aminotransferase (P = 0.0407) and a high serum soluble Fas antigen level (P = 0.0483). CONCLUSIONS: High production levels of soluble Fas antigen may be associated with a poor response to interferon therapy in chronic hepatitis C patients.

Adult↗
PubMed2000

Identification of multiple transcription factors, HLF, FTF, and E4BP4, controlling hepatitis B virus enhancer II.

Hepatitis B virus (HBV) enhancer II (EnII) is a hepatotropic cis element which is responsible for the hepatocyte-specific gene expression of HBV. Multiple transcription factors have been demonstrated to interact with this region. In this study, the region from HBV nucleotides (nt) 1640 to 1663 in EnII was demonstrated to be essential for enhancer activity and to be another target sequence of putative transcription factors. To elucidate the factors which bind to this region, we used a yeast one-hybrid screening system and cloned three transcription factors, HLF, FTF, and E4BP4, from a human adult liver cDNA library. All of these factors had binding affinity to the sequence from nt 1640 to 1663. Investigation of the effects of these factors on transcriptional regulation revealed that HLF and FTF had stimulatory activity on nt 1640 to 1663, whereas E4BP4 had a suppressing effect. FTF coordinately activated both 3. 5-kb RNA and 2.4/2.1-kb RNA transcription in a transient transfection assay with an HBV expression vector. HLF, however, activated only 3.5-kb RNA transcription, and in primer extension analysis, HLF strongly stimulated the synthesis of pregenome RNA compared to precore RNA. Thus, FTF stimulated the activity of the second enhancer, while HLF stimulated the activity of the core upstream regulatory sequence, which affects only the core promoter, and had a dominant effect on the pregenome RNA synthesis.

Base Sequence↗
PubMed1999

Intracellular single-chain antibody against hepatitis B virus core protein inhibits the replication of hepatitis B virus in cultured cells.

Hepatitis B virus (HBV) is one of the major causes of chronic liver diseases and hepatocellular carcinoma. In this study, we used a single chain antibody (sFv), which is a man-made antibody with a strong affinity of immunoglobulin, to inhibit HBV replication. Because HBV replication can only take place in the viral nucleocapsid made of HBV core protein (HBc), we generated anti-HBc sFv and examined whether intracellular anti-HBc sFv could inhibit viral replication in the human hepatoblastoma-derived cell line that produces HBV (HB611). With respect to HBV replication intermediates, both single-stranded and partially double-stranded DNA intermediates were markedly suppressed in the cells expressing anti-HBc sFv, although HBV RNA intermediates were not affected. This suggested that intracellular anti-HBc sFv inhibited HBV DNA replication by inhibiting reverse transcription from HBV pregenome RNA to single-stranded DNA. Because the sFv-HBc complex was detected in the cells expressing anti-HBc sFv by immunoprecipitation analysis but the quantity of intracellular HBc was not affected, the anti-HBc sFv was suggested to inhibit HBV DNA replication by interfering with the function of HBc. These results indicate that intracellular sFv against HBc might be effective as a novel active molecule for gene therapy of hepatitis B.

Amino Acid Sequence↗
PubMed1999

Interleukin 1beta protects mice from Fas-mediated hepatocyte apoptosis and death.

BACKGROUND & AIMS: Fas-mediated apoptosis is one of the major death processes of hepatocytes in liver diseases. The aim of this study was to determine whether interleukin (IL)-1beta regulates the Fas-mediated apoptotic process of differentiated hepatocytes in vivo. METHODS: IL-1beta was injected into Balb/cA mice 5 hours before lethal challenge with agonistic anti-Fas administration. Survival and hepatocyte apoptotic process of these mice were examined. RESULTS: IL-1beta pretreatment prolonged animal survival in a dose-dependent manner, and 500 ng of IL-1beta completely protected mice from lethality. Both serum alanine aminotransferase value and hepatic DNA fragmentation were significantly suppressed by IL-1beta pretreatment. IL-1beta affected neither hepatic distribution of anti-Fas antibody nor Fas expression levels on hepatocytes but significantly suppressed Fas-induced activation of hepatic caspase 3-like protease. Suppression of Fas-induced activation of the caspase by IL-1beta was diminished by coadministration with D-galactosamine and reversed by coinjection with an excess amount of uridine. CONCLUSIONS: These results suggest that IL-1beta suppresses Fas-mediated hepatocyte apoptosis by inducing molecule(s) that suppress the apoptosis control machinery upstream of caspase 3. This observation raises the possibility that IL-1beta acts as a negative regulator of Fas-mediated hepatocyte apoptosis during liver injury.

Alanine Transaminase↗
PubMed1999

Involvement of Fas system-mediated apoptosis in pathogenesis of viral hepatitis.

Enhanced Fas system-mediated hepatocyte apoptosis is observed in hepatitis C virus (HCV)- and hepatitis B virus (HBV)-associated chronic liver diseases. In these forms of viral hepatitis, liver-infiltrating lymphocytes that recognize the viral antigen on hepatocytes become activated and express cytolytic Fas ligand (FasL) molecules. In contrast, hepatocytes exhibit enhanced Fas expression and become susceptible to FasL-mediated death. Augmentation of the Fas system has also been observed in other liver diseases and biliary disorders. Moreover, the Fas system is involved in removing aged hepatocytes. Thus, Fas-mediated apoptosis plays an important role in several liver diseases and in maintaining normal liver homeostasis.

Animals↗
PubMed1999

Influence of transfusion-transmitted virus infection on the clinical features and response to interferon therapy in Japanese patients with chronic hepatitis C.

Recently, the genome of a novel DNA virus, transfusion-transmitted virus (TTV), was cloned from the plasma of a blood donor who had an elevated aminotransferase level but no serological markers of known hepatitis viruses. In this study, we investigated the influence of TTV infection on the clinical features and response to interferon (IFN) therapy in patients with chronic hepatitis C. We studied 247 patients who had received a 16- or a 24-week course of IFN-alpha therapy. The serum of these patients was analysed for TTV DNA using a hemi-nested polymerase chain reaction and TTV was detected in 114 patients (46%). No significant differences were found with respect to clinical features (gender, age, liver-related biochemical tests, hepatitis C virus (HCV) genotype and serum HCV RNA levels) between the patients who were positive for TTV DNA and those who were negative for TTV DNA. The fibrosis score was higher in TTV-positive patients (2.1 +/- 1.1) than in TTV-negative patients (1.7 +/- 1.1, P = 0.023). The biochemical sustained-response rate was 25% in TTV-positive patients and 25% in TTV-negative patients (not significant). A sustained HCV clearance rate was achieved in 26% of TTV-positive patients and in 22% of TTV-negative patients (not significant). TTV DNA clearance after IFN therapy was observed in 36 of 69 patients (52%) for whom stored serum samples were available. The disappearance of TTV DNA had no effect on the biochemical response to IFN therapy. In conclusion, TTV co-infection is frequently observed in Japanese patients with chronic hepatitis C. In chronic hepatitis C, TTV does not modify the clinical features or the response to IFN.

Adolescent↗
PubMed1999

Effects of nifedipine on bladder overactivity in rats with cerebral infarction.

PURPOSE: Our objective was to evaluate the effect of the calcium (Ca2+) channel blocking agent nifedipine on bladder overactivity induced by middle cerebral artery (MCA) occlusion and determine its site of action. MATERIALS AND METHODS: Seven days after implantation of a bladder catheter, a cannula for intracerebroventricular and intrathecal administration was implanted and the left MCA was occluded with 4-0 monofilament nylon thread in male SD rats. Twenty-four hours after the induction of cerebral ischemia, saline was infused into the bladder at a constant rate (200 microL/min.) and cystometrogram was measured in conscious state. Nifedipine was administered intracerebroventricularly (5 microL) or intrathecally (20 microL) at graded doses (0.15 ng.-0.15 microg., 0.15 microg. -1.5 microg., respectively). RESULTS: Bladder capacity in conscious rats was significantly reduced after the left MCA occlusion. Intracerebroventricular administration of nifedipine significantly increased bladder capacity in cerebral infarcted rats but not in sham operated rats. Furthermore there was no significant difference in bladder capacity between before and after intrathecal administration of nifedipine in cerebral infarcted rats. CONCLUSION: These results show that Ca2+ channel blocking agents can operate especially on the supraspinal central nervous system rather than on the spinal system in rats with neurogenic bladder overactivity following cerebral infarction.

Animals↗
PubMed1998

Delayed Fas-mediated hepatocyte apoptosis during liver regeneration in mice: hepatoprotective role of TNF alpha.

Fas-mediated apoptosis is one of the major death processes of hepatocytes in liver diseases. Although compensatory regeneration occurs during liver injury, it has not been determined whether regenerating hepatocytes die by the same apoptotic process as quiescent hepatocytes. To clarify this issue, the hepatocyte apoptotic process, after injection of agonistic anti-mouse Fas, was compared between sham-operated mice and two-thirds partially hepatectomized mice. The onset of hepatocyte apoptosis was retarded in hepatectomized mice, as evidenced by both morphological and biochemical observations, resulting in significantly prolonged animal survival. Flow cytometric analysis revealed similar levels of Fas expression on hepatocytes between hepatectomized mice and sham-operated mice; however, the activation of liver caspase-3-like protease after Fas stimulation was suppressed in hepatectomized mice, whereas pro-caspase-3 expression did not change with or without hepatectomy. Anti-tumor necrosis factor alfa (TNF alpha), when administered before hepatectomy, partially reversed suppression of caspase-3-like activity after Fas stimulation. Furthermore, the injection of TNF alpha into untreated mice suppressed caspase-3-like activity and prolonged animal survival after Fas stimulation. These results indicate that Fas-signaling events at the level or upstream of caspase-3-like protease are suppressed during liver regeneration, resulting in delayed hepatocyte apoptosis, and also that TNF alpha acts as one of the protective factors against Fas-mediated hepatocyte apoptosis.

Animals↗
PubMed1998

Effects of MK-801 on bladder overactivity in rats with cerebral infarction.

PURPOSE: Our objective was to evaluate the underlying mechanisms of neurogenic voiding dysfunction following cerebral infarction. MATERIALS AND METHODS: The left middle cerebral artery (MCA) was occluded using 4-0 monofilament nylon thread in male S-D rats. Cystometric examination was performed in unanesthetized and urethane-anesthetized rats through a catheter chronically implanted in the dome of the bladder. RESULTS: Bladder capacity of unanesthetized or urethane anesthetized rats was significantly reduced just after occlusion of the left MCA; 2 weeks after the occlusion, the capacity was less than half that in sham-operated rats. Intravenous administration of N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 to the unanesthetized sham-operated rats led to a marked dose-dependent decrease in bladder capacity. Its administration to unanesthetized rats with cerebral infarction resulted in a slight decrease in bladder capacity. In the urethane-anesthetized state, the bladder capacity of the rats with cerebral infarction was significantly increased by MK-801, 0.1 mg./kg., without inhibiting the contraction pressure or increasing the amount of residual urine. A high dose (1 mg./kg.) of MK-801 was required to increase the bladder capacity of sham-operated rats. This led to an inhibition of contraction pressure and an increase in residual urine. CONCLUSION: Results in urethane anesthetized rats indicate that NMDA glutamatergic transmission is important in the overactivity of the bladder following a cerebral infarction. This model is useful in studying the neurogenic voiding dysfunction observed in patients with cerebrovascular disease.

Anesthesia↗
PubMed1998

Serum levels of soluble Fas antigen in chronic hepatitis C patients.

BACKGROUND/AIMS: In chronic hepatitis C, the expression of Fas antigen on hepatocytes is upregulated and Fas ligand expression is detected on liver-infiltrating mononuclear cells. Thus Fas antigen/Fas ligand-mediated apoptosis is thought to be involved in hepatic injury in chronic hepatitis C. The soluble form of Fas antigen has been detected in serum and shown to inhibit Fas-mediated apoptosis. The present study was done to evaluate the relationship of serum soluble Fas antigen levels with disease activity. METHODS: Serum soluble Fas antigen levels were measured by enzyme-linked immunosorbent assay for 68 chronic hepatitis C patients and compared with those in normal volunteers, chronic hepatitis B patients and autoimmune hepatitis patients. These levels were compared with histological activity, ALT levels, HCV-RNA titer and Fas expression on hepatocytes. RESULTS: Serum soluble Fas antigen levels in chronic hepatitis C patients (3.24+/-1.55 ng/ml) were significantly higher than those in normal volunteers (1.70+/-1.01 ng/ml) (p<0.01). They showed no difference from those in chronic hepatitis B or autoimmune hepatitis patients. Histologically, soluble Fas antigen levels showed correlation with the levels of liver inflammation (p<0.01). However, no relationship was observed between serum soluble Fas antigen and serum ALT levels or HCV-RNA titer. Serum soluble Fas antigen levels showed correlation with the levels of Fas antigen expression in liver tissue (p<0.05). CONCLUSIONS: These findings suggest that serum soluble Fas antigen may reflect the expression levels of Fas antigen on hepatocytes and the severity of liver inflammation in chronic hepatitis C.

Adult↗
PubMed1998

GBV-C/HGV infection in chronic hepatitis C patients: its effect on clinical features and interferon therapy.

A novel virus (GBV-C/HGV) may be associated with some liver diseases including fulminant hepatitis and acute and chronic hepatitis. On the other hand, many investigations showed that this infection does not contribute to liver disease. GBV-C/HGV has been found to occur in association with infection with other hepatitis viruses. We investigated the effect of GBV-C/HGV infection on the clinical features and interferon treatment in patients with chronic hepatitis C. A total of 262 hepatitis C virus (HCV) RNA positive patients with chronic hepatitis were examined in this study. The detection of serum GBV-C/HGV RNA was done by RT-PCR using specific primers from the NS5 regions. Interferon-alpha was given at a dose of 6 MU/day for 16 or 24 weeks. A responder was defined as a patient with ALT normalization and HCV RNA disappearance after treatment. GBV-C/HGV RNA was detected in 28 (11%) patients. No significant difference was detected in clinical features (age, sex, liver-related biochemical tests, and histological examination) between the 28 GBV-C/HGV-positive patients and the GBV-C/HGV-negative patients. Using interferon therapy for hepatitis C, the responder rates of GBV-C/HGV-positive and -negative patients were 14% and 20%, respectively. Of the 28 patients with GBV-C/HGV RNA, GBV-C/HGV RNA was tested after interferon therapy in 16 and of these GBV-C/HGV RNA was not detected in nine patients after therapy. These findings suggest that GBV-C/HGV infection dose not affect the clinical features in patients with HCV and the efficacy of interferon therapy for chronic hepatitis C.

Adolescent↗
PubMed1997

Bladder compliance in patients with benign prostatic hyperplasia.

Factors influencing bladder compliance were examined in 116 patients with benign prostatic hyperplasia (BPH), by evaluating patients' histories, response of isolated bladder strips to acetylcholine, and the effect of prostatic urethral anesthesia. Patients' age, frequency of micturition, and duration of voiding difficulty were not correlated with bladder compliance. Bladder compliance was significantly low in patients within 30 days after urinary retention, as compared with bladder compliance in patients without an episode of retention. More than 30 days after retention, however, there was a tendency toward increased bladder compliance. Restricted to patients without an episode of retention, bladder compliance in the overactive detrusor group was found to be significantly lower than in the normal group. The responses to acetylcholine of bladder strips were compared between patients with low and normal-compliance bladders. The dose-response curve of patients with low-compliance bladders did not differ from that of those with normal compliance bladders, even when patients with an episode of retention were excluded. After prostatic urethral anesthesia, a significant increase of bladder compliance was observed in patients with an overactive detrusor, while the increase was not significant in patients with a normal detrusor. Our results strongly suggest that easy irritability of the anatomically altered prostatic urethra, as well as bladder over-distension caused by urinary retention, are important factors affecting bladder compliance in BPH patients.

Acetylcholine↗
PubMed1997

B7/BB-1 expression and hepatitis activity in liver tissues of patients with chronic hepatitis C.

Cytotoxic T lymphocytes (CTL) are closely related to the mechanism of liver injury in chronic viral hepatitis. Recently, it has been suggested that antigen-specific T cell activation requires both presentation of antigen by major histocompatibility complex (MHC) molecules and the delivery of costimulatory signals. Such signals are provided by B7/BB-1, one of the most important accessory molecules, sufficient for causing antigen-specific MHC-restricted T cell activation. To evaluate the role of B7/BB-1 in chronic hepatitis C, we immunohistochemically studied its expression in liver tissues obtained from 61 patients with hepatitis C virus (HCV) infection and compared them based on hepatitis activity. In HCV-infected liver, B7/BB-1 was strongly expressed in the cytoplasm of hepatocytes. B7/BB-1-positive cells accompanied liver-infiltrating lymphocytes and were mainly detected in the periportal region. B7/BB-1 expression was closely correlated with the activity of viral hepatitis as evaluated from scores of periportal or intralobular inflammation and necrosis, or serum alanine transferase (ALT) levels. Further study by immunostaining with anti-HCV core and anti-human leukocyte antigen (HLA) class I antibody showed B7/BB-1 positive cells near HCV core antigen- and HLA class I-positive cells, with B7/BB-1-positive cells mostly included among HLA class I-positive cells. These findings suggested that B7/BB-1 expression by hepatocytes may be induced by HCV infection and may trigger generation and activation of CTL, which may cause damage to HCV-infected HLA class I-expressing hepatocytes.

Adult↗
PubMed1997

Cleavage of viral RNA and inhibition of viral translation by hepatitis C virus RNA-specific hammerhead ribozyme in vitro.

BACKGROUND/AIMS: A hammerhead ribozyme has been used as a new way to suppress specific gene expression. We designed hammerhead ribozymes directed against hepatitis C virus RNA, and investigated their cleavage efficiency and inhibitory effect on viral translation in vitro. METHODS: Three hammerhead ribozymes bearing different cleavage sites in the core region of hepatitis C virus RNA (genotype 1b) were designed in this study. Ribozymes and the target hepatitis C virus RNA were synthesized by in vitro transcription. The cleavage efficiency was evaluated by the ribozyme cleavage assay. The inhibitory effect of the ribozyme on viral translation was further studied by the viral translation inhibition assay. RESULTS: All ribozymes specifically cleaved the target RNA of 1217 bases at a physiological temperature in a dose-dependent manner, with the specific cleavage increasing with a longer incubation period. The target RNA was cleaved most efficiently by the ribozyme with the cleavage site located nearest to the initiation codon. In the viral translation inhibition assay, all ribozymes showed a significant inhibitory effect on viral translation. The ribozyme with the cleavage site located farthest from the initiation codon blocked viral translation most efficiently, and demonstrated almost 70 to 80% inhibition. For ribozymes with the T7 transcription terminator sequence, both the target RNA cleavage and the inhibition of viral translation tended to be achieved less efficiently by ribozymes with T7 terminator than by those without it. CONCLUSIONS: These findings suggest that ribozyme-mediated hepatitis C virus RNA cleavage may serve as a new strategy in the treatment of hepatitis C virus infection.

Hepacivirus↗
PubMed1997

Fas system and apoptosis in viral hepatitis.

Hepatitis C virus (HCV) and hepatitis B virus (HBV) are the major causative agents of chronic liver disease. However, the mechanisms responsible for liver cell injury remain to be clarified. Playing crucial roles in the clearance of viral infection are cytotoxic T lymphocytes. Recently, it has been demonstrated that perforin- and Fas-based mechanisms account for all T cell-mediated cytotoxicity. Therefore, we examined the correlation between liver cell damage and the Fas system in the liver of patients with chronic hepatitis C. Fas is a cell surface protein that mediates apoptosis with treatment of the Fas ligand or the anti-Fas antibody. To investigate the role of Fas in type C hepatitis, we examined the correlation between liver cell damage and Fas expression. Fas expression was found mainly in the cytoplasm of hepatocytes and these positive cells were found particularly among infiltrating lymphocytes. A high prevalence of Fas expression was shown in liver tissue with more severe inflammation. The Fas system-mediated death signal requires the interaction of Fas ligand with Fas on target cells. We isolated a 1.9 kb cDNA clone for the human Fas ligand and examined the expression of the Fas ligand in liver-infiltrating mononuclear cells obtained from patients with chronic hepatitis C. The open reading frame encodes 281 amino acids. Next, we examined the expression of the Fas ligand in liver-infiltrating mononuclear cells obtained from patients with chronic hepatitis C. The amplified products (231 bp) derived from Fas ligand transcripts were detected in liver-infiltrating mononuclear cells, whereas no signal was observed in liver tissues. In HCV infection, Fas expression in hepatocytes is up-regulated in accordance with the severity of liver inflammation. When HCV-specific T cells migrate into hepatocytes and recognize the viral antigen via the T cell receptor, they become activated and express Fas ligand that can transduce the apoptotic death signal to Fas-bearing hepatocytes. Thus, the Fas system plays an important role in liver cell injury by HCV infection.

Antibodies, Viral↗
PubMed1997

Hepatitis C virus replicative levels and efficiency of genotyping by specific PCR and antibody assay.

We studied factors which influence the detection of hepatitis C virus genotypes by the group-specific PCR of the sequence within the core region gene and by the newly developed genotype-specific NS4 antibody assay. Genotyping was performed on 75 hepatitis C virus carriers in Japan, where patients with hepatitis C viremia are exclusively infected with genotype 1b, 2a, and 2b. PCR failed to identify genotypes in 8 (11%) patients, whereas 12 (16%) patients, including the 8 patients mentioned above, could not be genotyped by the serological assay. Serological genotypes showed almost complete agreement with those found by the PCR except that double infection was revealed in only two of the eight patients serologically judged to be coinfected with genotypes 1 and 2. In each assay, disease activity and levels of viremia assessed by a competitive reverse transcription PCR assay were significantly lower in patients infected with untypeable isolates than in those infected with typeable ones (P < 0.01). The PCR could identify the genotypes of isolates from all 64 patients with levels of viremia of > or = 10(6) copies/ml, and the genotype-specific antibody responses were found in 60 (94%) patients. In contrast, isolates from only 3 (27%) of 11 patients with low levels of viremia (< 10(6) copies/ml) could be genotyped by the PCR (P < 0.00001), and these patients showed the genotype-specific antibody responses (P < 0.00001). These findings suggest that low levels of hepatitis C virus replication may reduce the efficiency of genotyping by serological assay as well as by PCR.

Adult↗
PubMed1997

[Coinfection of hepatitis C virus and hepatitis G virus in patients with chronic hepatitis].

Hepatitis G virus(HGV) has been cloned and it is associated with liver diseases. We reported the influence of HGV infection on clinical features of patients with chronic hepatitis C. Subjects were 262 patients with HCV RNA. Detection of HGV RNA was performed by RT-PCR using specific primers from the NS5 regions. Of 262 patients, 28(11%) were positive HGV. No significant differences were detected in liver functions tests, histological examination and efficacy of interferon treatment between HGV-positive and HGV-negative patients with chronic hepatitis C. In conclusions, HGV infection did not influence clinical features of patients with chronic HCV infection.

Adult↗