PubMed Health⌕ Search

Biomedical subjects

Ken Sato

Publications and source records attributed to Ken Sato.

At least 19 recordsLinked to original sources
PubMed2006

The role of the nuclear receptor constitutive androstane receptor in the pathogenesis of non-alcoholic steatohepatitis.

BACKGROUND: Non-alcoholic fatty liver disease is a common liver injury, but the pathophysiological mechanisms leading to the development of non-alcoholic steatohepatitis (NASH) remain unclear. The pathological roles of the nuclear receptor constitutive androstane receptor (CAR), a key regulator of drug-metabolising enzymes, in the development of NASH were investigated. METHODS AND RESULTS: CAR(+/+) and CAR(-/-) mice were given a methionine and choline-deficient (MCD) diet to establish a dietary model of NASH. Increases in serum alanine aminotransferase (ALT) and in infiltration of inflammatory cells were dominant in CAR(+/+) mice at 8 weeks. There was no significant difference in the lipid concentration of the liver - namely, the first hit between CAR(+/+) and CAR(-/-) mice. The index of lipid peroxidation increased in liver of the CAR(+/+) mice, as demonstrated by 8-iso-prostaglandin F2alpha (F2-isoprostanes). Western blotting analysis showed that nuclear translocation of CAR occurred in CAR(+/+) mice fed the MCD diet. As a result, the CAR activation caused the lipid peroxidation - namely, the second hit. The expressions of cytochrome P450 (CYP)2B10, 2C29, 3A11 all increased considerably in the CAR(+/+) mice. Furthermore, alpha smooth muscle actin immunohistochemistry and Sirius red staining showed an increase in the degree of fibrosis in CAR(+/+) mice fed the MCD diet at 16 weeks. The mRNA expressions of collagen alpha1(1) and the tissue inhibitor of metalloproteinase-1 were found to be elevated in CAR(+/+) mice. CONCLUSION: CAR caused the worsening of the hepatic injury and fibrosis in the dietary model of NASH. Our results suggest that the CAR nuclear receptor may thus play a critical role in the pathogenesis of NASH.

Alanine Transaminase↗
PubMed2006

Integrative roles of transforming growth factor-alpha in the cytoprotection mechanisms of gastric mucosal injury.

BACKGROUND: Transforming growth factor alpha (TGFalpha) protects against gastric mucosal injury and facilitates wound healing. However, its overexpression is known to induce hypertrophic gastropathy resembling Menetrier's disease in transgenic (TG) mice on an FVB background, as one of the authors reported previously. We studied another TGFalpha-expressing mouse line on a CD1 background, whose gastric mucosa appears normal. Since this TG mouse had a strong resistance to ethanol-induced gastric injury, we considered the long-term effect of TGFalpha on several gastric protection mechanisms. METHODS: TGFalpha-expressing transgenic (TG) mouse lines bearing human TGFalpha cDNA under the control of the mouse metallothionein gene I promoter were generated on a CD1 mouse background, and analyzed their ethanol injury-resistant phenotypes produced by TGFalpha. RESULTS: In the TG mucosa, blood flow was well maintained after ethanol injury. Further, neural and inducible types of NO synthases were consistently and widely expressed in the TG mucosa, compared with the limited distribution of neural type NO synthase in the luminal pit region of the wild-type (WT) mucosa. COX-2 and its upstream transcription factor NfkB were constitutively elevated in the TG mucosa even before ethanol administration, whereas they were induced in the same region of the WT mucosa only after ethanol injury. Two anti-apoptotic proteins, HSP70 and Bcl-2, were upregulated in the TG mucosa even before ethanol administration, while they were not expressed in the WT mucosa before the injury. Furthermore, pro-caspase 3 activation was inhibited in the TG mucosa, while it was converted to the active form in the WT mucosa following ethanol administration. CONCLUSION: We conclude that TGFalpha maintains the gastric mucosal defense against gastric injury by integrating other cytoprotective mechanisms.

Animals↗
PubMed2006

The Arf1p GTPase-activating protein Glo3p executes its regulatory function through a conserved repeat motif at its C-terminus.

ADP-ribosylation factors (Arfs), key regulators of intracellular membrane traffic, are known to exert multiple roles in vesicular transport. We previously isolated eight temperature-sensitive (ts) mutants of the yeast ARF1 gene, which showed allele-specific defects in protein transport, and classified them into three groups of intragenic complementation. In this study, we show that the overexpression of Glo3p, one of the GTPase-activating proteins of Arf1p (ArfGAP), suppresses the ts growth of a particular group of the arf1 mutants (arf1-16 and arf1-17). Other ArfGAPs do not show such a suppression activity. All these ArfGAPs show sequence similarity in the ArfGAP catalytic domain, but are divergent in the rest of molecules. By domain swapping analysis of Glo3p and another ArfGAP, Gcs1p, we have shown that the non-catalytic C-terminal region of Glo3p is required for the suppression of the growth defect in the arf1 ts mutants. Interestingly, Glo3p and its homologues from other eukaryotes harbor a well-conserved repeated ISSxxxFG sequence near the C-terminus, which is not found in Gcs1p and its homologues. We name this region the Glo3 motif and present evidence that the motif is required for the function of Glo3p in vivo.

ADP-Ribosylation Factor 1↗
PubMed2006

Dynamic regulation of caveolin-1 trafficking in the germ line and embryo of Caenorhabditis elegans.

Caveolin is the major protein component required for the formation of caveolae on the plasma membrane. Here we show that trafficking of Caenorhabditis elegans caveolin-1 (CAV-1) is dynamically regulated during development of the germ line and embryo. In oocytes a CAV-1-green fluorescent protein (GFP) fusion protein is found on the plasma membrane and in large vesicles (CAV-1 bodies). After ovulation and fertilization the CAV-1 bodies fuse with the plasma membrane in a manner reminiscent of cortical granule exocytosis as described in other species. Fusion of CAV-1 bodies with the plasma membrane appears to be regulated by the advancing cell cycle, and not fertilization per se, because fusion can proceed in spe-9 fertilization mutants but is blocked by RNA interference-mediated knockdown of an anaphase-promoting complex component (EMB-27). After exocytosis, most CAV-1-GFP is rapidly endocytosed and degraded within one cell cycle. CAV-1 bodies in oocytes appear to be produced by the Golgi apparatus in an ARF-1-dependent, clathrin-independent, mechanism. Conversely endocytosis and degradation of CAV-1-GFP in embryos requires clathrin, dynamin, and RAB-5. Our results demonstrate that the distribution of CAV-1 is highly dynamic during development and provides new insights into the sorting mechanisms that regulate CAV-1 localization.

ADP-Ribosylation Factor 1↗
PubMed2006

Living-related liver transplantation for multiple liver metastases from rectal carcinoid tumor: a case report.

A 42-year-old woman was admitted to our hospital because of multiple liver tumors detected by ultrasonography. Colonoscopy revealed submucosal tumor in the rectum, which was considered the primary lesion. Endoscopic mucosal resection followed by histopathological examination revealed that the tumor was carcinoid. The resected margin of the tumor was positive for malignant cells. Two courses to transcatheter arterial chemotherapy for liver metastasis were ineffective. Accordingly, the rectal tumor and metastatic lymph nodes were surgically resected. One month after the operation, she received liver transplantation (left lateral segment and caudate lobe) from her son. No recurrent lesion has been observed at two years after the liver transplantation. Liver transplantation should be considered as a treatment option even in advanced case of carcinoid metastasis to the liver. We also discuss the literature on liver transplantation for metastatic carcinoid tumor.

Adult↗
PubMed2006

Spontaneous regression of hepatic inflammatory pseudotumor with primary biliary cirrhosis: case report and literature review.

Hepatic inflammatory pseudotumor (IPT) is a rare benign non-neoplastic lesion characterized by proliferating fibrous tissue infiltrated by inflammatory cells. The exact etiology of IPT remains unclear. Although the association of IPT with systemic inflammatory disorders has been well established, a specific relationship with cholangitis is distinctly rare. We report a case of spontaneous regression of hepatic IPT with primary biliary cirrhosis (PBC). To date, only two cases of IPT with PBC have been reported. In our case, however, IPT developed during the course of improvement of cholangitis of PBC induced by effective treatment, differing from two previously reported cases. Our case indicates that the development of IPT does not also relate to the activity of cholangitis and/or hyper gamma-globulinemia, since our case was confirmed radiologically to be free of IPT when biliary enzymes and immunoglobulins were much higher than the corresponding values on admission. Comparison of our case with the two previously reported cases suggests that IPT occurring with PBC does not represent the same disease entity or be a bystander for PBC.

Aged↗
PubMed2006

Triple therapy of interferon and ribavirin with zinc supplementation for patients with chronic hepatitis C: a randomized controlled clinical trial.

AIM: To study the therapeutic effect of interferon (IFN) and ribavirin with zinc supplement on patients with chronic hepatitis C viral (HCV) infection. METHODS: A total of 102 patients confirmed histologically to have chronic HCV infection with genotype 1b and more than 100 KIU/mL of HCV were randomly assigned to each arm of the study and each received 10 million units of pegylated interferon (IFN-alpha-2b) daily for 4 wk followed by the same dose every other day for 20 wk plus ribavirin (600 or 800 mg/d depending on body weight), with or without polaprezinc (150 mg/d) orally for 24 wk. The primary endpoint was sustained virological response (SVR) defined as negative HCV-RNA in the serum 6 mo after treatment. RESULTS: There were no differences in the clinical background between the two groups except for more females in the dual therapy group than in the other group (P<0.05). SVR was observed in 33.3% of the triple therapy group and 33.3% of the dual therapy group. The side effects were almost the same in both groups except for gastrointestinal symptoms, which were less in the triple therapy group (P=0.019). CONCLUSION: Considered together, triple therapy of zinc plus IFN and ribavirin for HCV infection patients with genotype 1b and high viral load is not better than dual therapy except for lower incidence of gastrointestinal side effects.

Adult↗
PubMed2006

Alteration of serum cytokine balances among different phases of chronic hepatitis B virus infection.

To understand the pathogenesis of chronic hepatitis B virus (HBV) infection, we examined the serum levels of IL-10, TNF-alpha IL-12 p70, and IL-12 p40 in 77 patients chronically infected with HBV and 19 controls. The patients were classified into four groups: asymptomatic carriers (ASC), patients with chronic hepatitis (CH), patients with liver cirrhosis (LC), and patients with hepatocellular carcinomas (HCC). The cytokine values among these groups were compared and their relations to clinical parameters were investigated. All these cytokine values were higher in the patient groups than in controls. IL-10 and TNF-alpha became higher in accordance with the progress of the disease phases, from ASC to LC, and lowest when the patients had HCC. IL-12 p40 was also lowest in HCC, however, the group with highest levels was CH. IL-12 p70 was unchanged among ASC, CH, and LC, but were raised in HCC. Serial analyses for the cytokine values in the same patients showed the similar tendencies. Regression analysis showed the significant correlations between ALT and IL-10. Serum cytokine values well reflected the pathological differences of the individual disease phases, and may become useful indices to understand the pathogenesis of chronic HBV infection.

Journal Article↗
PubMed2006

Pneumatosis cystoides intestinalis after alpha-glucosidase inhibitor treatment in a patient with interstitial pneumonitis.

A 56-year-old woman was admitted to our hospital for treatment of non-specific interstitial pneumonitis (NSIP). The patient started prednisone treatment, but one month later treatment with voglibose, an alpha-glucosidase inhibitor (alpha-GI), was started because of prednisone-induced diabetes mellitus. One week later, a massive volume of free air below the diaphragm was detected by a chest X-ray examination. An abdominal CT examination demonstrated pneumatosis coli and the patient was diagnosed with pneumatosis cystoides intestinalis (PCI). Voglibose was discontinued and parenteral nutrition and oxygen inhalation were initiated. Radiographic findings of PCI disappeared within 7 days. We encountered a rare case of PCI, that was associated with alpha-GI treatment.

Diabetes Mellitus↗
PubMed2006

Randomized controlled trial of consensus interferon with or without zinc for chronic hepatitis C patients with genotype 2.

AIM: The beneficial effect of zinc supplementation on the efficacy of interferon as a treatment for chronic hepatitis C had been demonstrated in hepatitis virus genotype 1b of high viral load. This study focused on patients with genotype 2, which is more sensitive to interferon than genotype 1b, and used consensus interferon (CIFN) with or without zinc. METHODS: We randomized 83 patients with chronic hepatitis C to CIFN at 18 MIU six times/wk for 4 wk, followed by CIFN at 18 MIU six times/wk for another 20 wk, in combination with polaprezinc 300 mg (regimen A, n=41) or as monotherapy (regimen B, n=42). Thirty-one patients in regimen A and 33 patients in regimen B completed the clinical trial; the remaining patients withdrew because of side effects or a transfer to another hospital. RESULTS: Sustained biochemical response, defined as a normal aminotransferase level at the end of the 6-mo post-treatment observation, was 68% and 69%, and sustained virological response, defined as undetectable HCV-RNA at the end of the 6-mo post-treatment observation, was 54% and 67% for regimens A and B, respectively. CONCLUSION: CIFN treatment combined with zinc did not enhance the effect of CIFN as shown by biochemical, virological criteria. No side effects related to polaprezinc were noted.

Adult↗
PubMed2006

Computed tomography-guided transpulmonary radiofrequency ablation for hepatocellular carcinoma located in hepatic dome.

AIM: To determine the feasibility of performing computed tomography (CT)-guided transpulmonary radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) located in the hepatic dome. METHODS: A total of seven patients with HCC comprising seven nodules located in the hepatic dome were treated from April 2004 to December 2004. CT-guided transpulmonary RFA was performed using a cool-tip type electrode (Radionics Company) based on a standardized energy protocol. All tumors located in the hepatic dome were not detectable by the usual ultrasound (US) methods. The lesion diameters ranged from 15 to 27 mm. RESULTS: RFA was technically feasible in all the patients. The puncture procedure was performed twice or less and the total average performance time was 40.6 min. Local tumor control was achieved in all the patients. The necrosis diameter ranged from 25 to 35 mm. The mean follow-up period was 9.6 (7-14 mo) mo. There was no local recurrence at the follow-up points. Pneumothorax requiring pleural drainage was the main complication, which was observed in two of the seven patients (28.6%). However, it improved with chest drainage tube, and the tube could be removed within 2-3 d. No other major complications were observed. CONCLUSION: CT-guided puncture is useful for the treatment of tumors located in the hepatic dome which are hardly detectable by US, even though pneumothorax sometimes may occur as a complication. In the cases with adhesion in the pleura for which artificial pleural effusion methods are not appropriate, CT-guided RFA is thus considered to be an alternative treatment for HCC located in the hepatic dome.

Aged↗
PubMed2006

Different outcomes of nosocomial infection with hepatitis C virus from the same origin.

The outcome of infection with hepatitis C virus (HCV) varies substantially from self-limiting infection to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma among the individuals. The mechanisms that determine the clearance or the persistence of HCV have not yet been clarified. Here, we experienced two cases of hospital-related infection with HCV from the same origin but with quite different outcomes. One case resolved after an episode of acute hepatitis, while the other case developed a chronic hepatitis although they were infected with HCV of the same origin. Although infected with the virus of the same origin, the clinical and virological courses were completely different. This suggests that host factors play a major role in conditioning the outcome of acute HCV infection.

Adult↗
PubMed2006

Structures of the carbohydrate recognition domain of Ca2+-independent cargo receptors Emp46p and Emp47p.

Emp46p and Emp47p are type I membrane proteins, which cycle between the endoplasmic reticulum (ER) and the Golgi apparatus by vesicles coated with coat protein complexes I and II (COPI and COPII). They are considered to function as cargo receptors for exporting N-linked glycoproteins from the ER. We have determined crystal structures of the carbohydrate recognition domains (CRDs) of Emp46p and Emp47p of Saccharomyces cerevisiae, in the absence and presence of metal ions. Both proteins fold as a beta-sandwich, and resemble that of the mammalian ortholog, p58/ERGIC-53. However, the nature of metal binding is distinct from that of Ca(2+)-dependent p58/ERGIC-53. Interestingly, the CRD of Emp46p does not bind Ca(2+) ion but instead binds K(+) ion at the edge of a concave beta-sheet whose position is distinct from the corresponding site of the Ca(2+) ion in p58/ERGIC-53. Binding of K(+) ion to Emp46p appears essential for transport of a subset of glycoproteins because the Y131F mutant of Emp46p, which cannot bind K(+) ion fails to rescue the transport in disruptants of EMP46 and EMP47 genes. In contrast the CRD of Emp47p binds no metal ions at all. Furthermore, the CRD of Emp46p binds to glycoproteins carrying high mannosetype glycans and the is promoted by binding not the addition of Ca(2+) or K(+) ion in These results suggest that Emp46p can be regarded as a Ca(2+)-independent intracellular lectin at the ER exit sites.

Amino Acid Sequence↗
PubMed2006

Hepatocellular carcinoma in extremely elderly patients: an analysis of clinical characteristics, prognosis and patient survival.

AIM: To identify the clinical and prognostic features of patients with hepatocellular carcinoma (HCC) aged 80 years or more. METHODS: A total of 1310 patients with HCC were included in this study. Ninety-one patients aged 80 years or more at the time of diagnosis of HCC were defined as the extremely elderly group. Two hundred and thirty-four patients aged > or = 50 years but less than 60 years were regarded as the non-elderly group. RESULTS: The sex ratio (male to female) was significantly lower in the extremely elderly group (0.90:1) than in the non-elderly group (3.9:1, P < 0.001). The positive rate for HBsAg was significantly lower in the extremely elderly group and the proportion of patients negative for HBsAg and HCVAb obviously increased in the extremely elderly group (P < 0.001). There were no significant differences in the following parameters: diameter and number of tumors, Child-Pugh grading, tumor staging, presence of portal thrombosis or ascites, and positive rate for HCVAb. Extremely elderly patients did not often receive surgical treatment (P < 0.001) and they were more likely to receive conservative treatment (P < 0.01). There were no significant differences in survival curves based on the Kaplan-Meier methods in comparison with the overall patients between the two groups. However, the survival curves were significantly worse in the extremely elderly patients with stage I/II, stage I/II and Child-Pugh grade A cirrhosis in comparison with the non-elderly group. The causes of death did not differ among the patients, and most cases died of liver-related diseases even in the extremely elderly patients. CONCLUSION: In the patients with good liver functions and good performance status, aggressive treatment for HCC might improve the survival rate, even in the extremely elderly patients.

Adult↗
PubMed2006

The significance of aberrant CHFR methylation for clinical response to microtubule inhibitors in gastric cancer.

BACKGROUND: We studied the correlations between CHFR (checkpoint with FHA and RING finger) gene methylation and responses to microtubule inhibitors (MI) in gastric cancer. METHODS: We examined 9 gastric cancer cell lines and 46 gastric cancer specimens from patients who underwent surgical resection. Promoter methylation was determined by methylation-specific polymerase chain reaction (MSP). CHFR mRNA expression was estimated by quantitative reverse transcription-PCR. The MI-induced growth inhibition was assayed by a standard MTT method. RESULTS: CHFR expression was silenced by aberrant promoter methylation in 3 of 9 gastric cancer cell lines. The level of CHFR mRNA expression was closely correlated with IC(50) in the MI-treated cells (R=0.889, P=0.005). In 46 patients with gastric cancers, 24 (52%) presented aberrant CHFR methylation. Among them, 12 patients had received treatment with MI because of advanced-stage tumor or tumor recurrence after surgery. The responders to the MI treatment were 29% in patients with CHFR methylation and 20% in those without the methylation. However, 6 (86%) of 7 patients with methylated CHFR tumor showed some regression or no progression, whereas 4 (80%) of 5 patients with unmethylated CHFR tumor manifested progressive deterioration. CONCLUSIONS: These observations indicated that CHFR methylation may be a clinically useful approach to predict the responsiveness of gastric cancers to treatment with MI.

Adult↗