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Sadako Yamada

Publications and source records attributed to Sadako Yamada.

6 recordsLinked to original sources
PubMed2006

Expression of oxidative stress-related molecules in circulating leukocytes and urine in patients with chronic viral hepatitis.

AIMS: Oxidative stress plays a role in pathogenesis of chronic viral hepatitis. Expression of oxidative stress-related molecules remains to be clarified. METHODS: 4-hydroxy-2-nonenal (4-HNE), 4-hydroxy-2-hexenal (4-HHE), catalase, superoxide dismutase-1 (SOD-1), glutathione peroxidase-1, thioredoxin (TRX) in leukocytes and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) were examined in 164 persons, including 130 chronic viral hepatitis patients and 34 normal individuals, by Western blot analysis and enzyme-linked immunosorbent assay, respectively. Hepatic expression of these proteins was immunohistochemically examined in 12 patients with chronic viral hepatitis, compared with three persons without liver damage. RESULTS: The 4-HNE/beta-actin ratios in chronic viral hepatitis were significantly higher than those in normal individuals (P<0.01), and were significantly correlated with asparate aminotransferase (AST) and alanine aminotransferase (ALT) (P<0.01, each). The catalase/beta-actin and SOD-1/beta-actin ratios in chronic viral hepatitis were higher than those in normal individuals, and were significantly correlated with 4-HNE/beta-actin ratios (P<0.01, each). Hepatic expression of 4-HNE, 4-HHE, catalase, SOD-1 and TRX in chronic viral hepatitis was higher than that without liver damage. Urinary excretion of 8-OHdG was not changed in chronic viral hepatitis. CONCLUSIONS: The results of the present study suggest that expression of oxidative stress-related molecules in leukocytes is upregulated in relation to serum aminotransferase levels.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2004

Retinoic acid receptor alpha dominant negative form causes steatohepatitis and liver tumors in transgenic mice.

Although attention has focused on the chemopreventive action of retinoic acid (RA) in hepatocarcinogenesis, the functional role of RA in the liver has yet to be clarified. To explore the role of RA in the liver, we developed transgenic mice expressing RA receptor (RAR) alpha- dominant negative form in hepatocytes using albumin promoter and enhancer. At 4 months of age, the RAR alpha- dominant negative form transgenic mice developed microvesicular steatosis and spotty focal necrosis. Mitochondrial beta-oxidation activity of fatty acids and expression of its related enzymes, including VLCAD, LCAD, and HCD, were down-regulated; on the other hand, peroxisomal beta-oxidation and its related enzymes, including AOX and BFE, were up-regulated. Expression of cytochrome p4504a10, cytochrome p4504a12, and cytochrome p4504a14 was increased, suggesting that omega-oxidation of fatty acids in microsomes was accelerated. In addition, formation of H2O2 and 8-hydroxy-2'-deoxyguanosine was increased. After 12 months of age, these mice developed hepatocellular carcinoma and adenoma of the liver. The incidence of tumor formation increased with age. Expression of beta-catenin and cyclin D1 was enhanced and the TCF-4/beta-catenin complex was increased, whereas the RAR alpha/ beta-catenin complex was decreased. Feeding on a high-RA diet reversed histological and biochemical abnormalities and inhibited the occurrence of liver tumors. These results suggest that hepatic loss of RA function leads to the development of steatohepatitis and liver tumors. In conclusion, RA plays an important role in preventing hepatocarcinogenesis in association with fatty acid metabolism and Wnt signaling.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2003

Expression of 8-hydroxy-2'-deoxyguanosine in chronic liver disease and hepatocellular carcinoma.

Reactive oxygen species may be involved in the progression of chronic liver disease and the occurrence of hepatocellular carcinoma (HCC). To clarify whether clinicopathological findings in liver diseases are related to oxidative DNA damage, hepatic expression of the 8-hydroxy-2'-deoxyguanosine (8-OHdG) was examined in 75 liver disease patients, which included 32 chronic hepatitis (CH), 13 liver cirrhosis (LC) and 30 HCC patients. The CH patients had higher 8-OHdG-positive hepatocytes than LC (P < 0.05). In CH and LC, the number of 8-OHdG-positive hepatocytes was correlated with alanine aminotransferase and asparate aminotransferase (P < 0.01 and P < 0.05, respectively). Of 30 HCC cases, 25 cases (83%) showed stronger immunoreactivity than non-cancerous counterparts. The patients with poorly differentiated HCC had a larger tumor size and higher levels of AFP, and exhibited higher labeling indices of PCNA-, TUNEL- and 8-OHdG-positive cells than those with well and moderately differentiated HCC. Our findings suggest that oxidative DNA damage is increased in association with necroinflammation in chronic liver disease and determination of 8-OHdG is useful in assessing high-grade malignancy in HCC.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2002

Increase in serum 7S domain of type IV collagen and N-terminal propeptide of type III procollagen levels with normal serum transaminase levels after long-term oral administration of Tegaful-Uracil.

To evaluate whether oral administration of Tegaful-Uracil (UFT(R)), a biochemical modulator of 5-fluorouracil that contains tegafur and uracil, can induce hepatic fibrosis, serum 7S domain of type IV collagen and N-terminal propeptide of type III procollagen levels were measured in 63 UFT(R)-treated, 38 tegafur-treated and 40 untreated patients. Serum transaminase and bilirubin levels were normal in almost all patients. Serum levels of 7S collagen and type III propeptide increased in 25 and 17% of the UFT(R)-treated patients, respectively, although a majority of tegafur-treated and untreated patients showed no increase in these markers. The patients with the elevated levels demonstrated mild or moderate hepatic fibrosis without necroinflammation in the liver. Both serum levels decreased markedly after the discontinuation of UFT(R). These findings suggest that long-term oral administration of UFT(R) can induce hepatic fibrosis without the elevation of serum transaminase levels and necroinflammation in the liver, and serum 7S collagen and type III procollagen are of diagnostic value for UFT(R)-induced hepatotoxicity.

Journal Article↗