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Dive into the research topics where Yujiro Ikuta is active.

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Featured researches published by Yujiro Ikuta.


European Journal of Haematology | 2001

Incidence of hepatitis virus infection and severe liver dysfunction in patients receiving chemotherapy for hematologic malignancies

Toshio Kawatani; Takeaki Suou; Fumihito Tajima; Kiyomi Ishiga; Hiromi Omura; Akira Endo; Hiroshi Ohmura; Yujiro Ikuta; Youko Idobe; Hironaka Kawasaki

Abstract: Hepatitis virus infection through virus reactivation has a high risk of mortality in patients with hematological malignancies receiving chemotherapy. We examined the incidence of both hepatitis B virus (HBV) and hepatitis C virus (HCV) infection and severe liver dysfunction (alanine aminotransferase >ten times the normal upper limit and total bilirubin >5 mg/dl) during chemotherapy in 268 patients with hematological malignancies. Eight patients (3.0%) were infected with HBV and 22 patients (8.2%) were infected with HCV. One patient (0.4%) was infected with both HBV and HCV. HBV‐ or HCV‐infected patients showed severe liver dysfunction at a significantly higher incidence than non‐infected patients (11/31 (35.5%) vs. 0/237 (0%), p<0.0001). Furthermore, the incidence of severe liver dysfunction in HBV‐infected patients was significantly higher than in HCV‐infected patients (6/8 (75.0%) vs. 4/22 (18.2%), p<0.01). Three of eight HBV‐infected patients were initially negative for hepatitis B surface antigen (HBsAg) by latex agglutination and became positive for HBsAg during chemotherapy. Furthermore, all three patients developed severe liver dysfunction and two developed fatal fulminant hepatitis. From an examination of the original stock of serum samples before chemotherapy, two patients were found to be positive for HBV‐DNA by polymerase chain reaction (PCR). Although post‐transfusion HBV infection was suspected in the one remaining patient, the cause of HBV infection could not be clarified due to the impossibility of examination in blood donors. Since HBV‐infected patients develop severe liver dysfunction at a higher incidence than either patients not infected with virus or HCV‐infected patients before chemotherapy for hematological malignancies, it is recommended that HBV‐DNA should be tested by PCR to detect HBV marker‐negative carriers and liver function tests should be carefully monitored.


Journal of Hepatology | 1997

Tissue inhibitor of metalloproteinase-1 in the liver of patients with chronic liver disease.

Yoshikazu Murawaki; Yujiro Ikuta; Youko Idobe; Yukisato Kitamura; Hironaka Kawasaki

BACKGROUND/AIMS Tissue inhibitor of metalloproteinase (TIMP)-1 is an important regulator of matrix metalloproteinase activity. To clarify the changes in TIMP-1 in diseased livers, we measured TIMP-1 concentrations in liver tissue samples from patients with chronic liver disease. The relationship between serum and liver levels of TIMP-1 was also examined in some patients. METHODS The subjects were 68 patients who underwent liver biopsy. The liver TIMP-1 concentration was measured using an enzyme immunoassay after the extraction of TIMP-1 with 2 M guanidine. RESULTS As compared with the controls (n=10), the liver TIMP-1 level was increased 2.2-fold in the 24 chronic active hepatitis 2A patients, 2.9-fold in the 10 chronic active hepatitis 2B patients and 4.1-fold in the six liver cirrhosis patients, but no significant increase was observed among the 18 chronic persistent hepatitis patients. The liver TIMP-1 levels were closely correlated with the histological degrees of periportal necrosis, portal inflammation, and liver fibrosis. When the localization of TIMP-1 was examined immunohistochemically, TIMP-1 was stained mainly in hepatocytes, and the intensity was stronger in the livers of chronic active hepatitis and liver cirrhosis patients than in those of the chronic persistent hepatitis patients. The serum TIMP-1 and liver TIMP-1 levels were significantly correlated, indicating that serum TIMP-1 could reflect the change of liver TIMP-1 in patients with chronic liver disease. CONCLUSION Liver TIMP-1 concentration increases with progression of the liver disease, when the degradation of extracellular matrix proteins is decreased, resulting in the development of liver fibrosis.


Journal of Gastroenterology | 2001

Diagnostic value of serum markers of connective tissue turnover for predicting histological staging and grading in patients with chronic hepatitis C.

Yoshikazu Murawaki; Yujiro Ikuta; Kinya Okamoto; Masahiko Koda; Hironaka Kawasaki

Purpose. Chronic hepatitis C is an insidiously progressive disease, in which repeated assessment of liver histology is required. Various serum fibrotic markers have now been introduced. Our present aim was to assess, by receiver operating characteristic analysis, the usefulness of serum fibrotic markers for diagnosing fibrotic staging and necroinflammatory grading in chronic hepatitis C. Methods. Serum levels of procollagen type III N-terminal peptide (PIIINP), 7S fragment of type IV collagen (PIVNP), hyaluronan (HA), matrix metalloproteinase (MMP)-1, MMP-2, and tissue inhibitor of metalloproteinases (TIMP)-1 were measured in 169 patients with chronic hepatitis C. Results. The accuracy of these tests for discriminating stages greater than F2 from stages less than F1 was superior to that for discriminating stage F3 from stages less than F2. The most useful test for predicting stages greater than F2 was the serum HA test (cutoff value, 50 ng/ml; sensitivity, 75%; specificity, 80%), and the next-most useful was the serum MMP-2 test (cutoff value, 550 ng/ml; sensitivity, 75%; specificity, 70%). The usefulness of these tests for discriminating moderate grade from grades less than mild was superior to that for discriminating grades more than mild from minimal grade. The most useful test for predicting moderate grade was the serum HA test (cutoff value, 60 ng/ml; sensitivity, 77%; specificity, 74%), and the second-most useful was the serum PIVNP test (cutoff value, 6.5 ng/ml; sensitivity, 74%; specificity, 75%). The combination of the most useful and next-most useful test results increased the accuracy of the diagnosis of staging and grading. Conclusions. These serum fibrotic markers, especially the serum HA test, would be clinically useful for assessing staging and grading in patients with chronic hepatitis C.


Journal of Gastroenterology and Hepatology | 1996

Clinical significance of serum hyaluronan in patients with chronic viral liver disease

Yoshikazu Murawaki; Yujiro Ikuta; Masahiko Koda; Yuuko Nishimura; Hironaka Kawasaki

In order to elucidate the clinical significance of serum hyaluronan in chronic viral hepatitis, serum hyaluronan concentrations were measured using a sandwich enzyme binding assay in 115 patients with chronic viral hepatitis. These findings were examined in relation to the results of laboratory liver tests, levels of serum markers for fibrosis and liver histological findings. Serum hyaluronan levels increased with the progress of liver disease, particularly in liver cirrhosis. There were no significant differences in serum hyaluronan levels among the cirrhotic patients according to Childs grade. Multivariate analysis showed that the significant independent predictors of serum hyaluronan were serum aspartate aminotransferase (P= 0.020), serum alanine aminotransferase (P= 0.008), serum cholinesterase (P< 0.001), particularly serum type IV collagen 7S domain (P< 0.0001), and the histological degree of liver fibrosis (P< 0.0001). These findings suggest that elevated serum hyaluronan levels are closely related to the severity of liver fibrosis. We assessed the predictive value of serum hyaluronan in differentiating cirrhosis from chronic hepatitis, constructing receiver operating curves; we found that serum hyaluronan was a better test for diagnosing cirrhosis than serum type IV collagen 7S domain and laboratory liver tests.


Journal of Hepatology | 1996

Comparison of serum 7S fragment of type IV collagen and serum central triple-helix of type IV collagen for assessment of liver fibrosis in patients with chronic viral liver disease

Yoshikazu Murawaki; Yujiro Ikuta; Masahiko Koda; Sadako Yamada; Hironaka Kawasaki

BACKGROUND/AIMS A competitive radioimmunoassay for serum 7S fragment of type IV collagen (7S collagen) using a polyclonal antibody against 7S collagen and a sandwich enzyme immunoassay for serum central triple-helix of type IV collagen (IV collagen) using two monoclonal antibodies against the pepsin-solubilized type IV collagen may be used as diagnostic aids for liver fibrosis in clinical medicine. We compared the clinical usefulness for assessing liver fibrosis of serum 7S collagen and IV collagen tests in chronic viral liver diseases, and also examined the elution pattern of 7S collagen- and IV collagen-related antigens in serum by gel filtration analysis. METHODS Serum 7S collagen and IV collagen levels were assayed in 151 patients with chronic viral liver disease and 30 healthy control subjects. RESULTS Gel filtration on the Sephacryl S400HR column revealed that the 7S collagen antigenicity in serum was heterogeneous, whereas the IV collagen antigen in serum was uniform in size. Serum levels of 7S collagen and IV collagen showed increases closely correlated with the severity of liver disease. The abnormal percentage of 7S collagen in three patient groups was similar to that of IV collagen in the corresponding groups. Serum 7S collagen and IV collagen levels were strongly correlated with the histological degree of liver fibrosis; the correlation coefficients were r = +0.675 for 7S collagen and r = +0.665 for IV collagen. When we assessed the ability of each test to detect cirrhosis with a receiver operating curve, the serum 7S collagen test was a slightly better marker than the serum IV collagen test. For the detection of cirrhosis, serum 7S collagen was 83% sensitive and 88% specific at a cutoff value of 9 ng/ml, and serum IV collagen was 80% sensitive and 81% specific at a cutoff value of 160 ng/ml. CONCLUSIONS These findings suggested that serum 7S collagen and IV collagen tests are similarly useful for assessing liver fibrosis in patients with chronic viral liver disease, although the former is slightly better for diagnosing cirrhosis than the latter.


Clinica Chimica Acta | 1999

Clinical usefulness of serum tissue inhibitor of metalloproteinases (TIMP)-2 assay in patients with chronic liver disease in comparison with serum TIMP-1

Yoshikazu Murawaki; Yujiro Ikuta; Hironaka Kawasaki

Tissue inhibitors of metalloproteinases (TIMPs) are involved in liver fibrosis through impaired matrix degradation. Previous studies showed that the serum level of TIMP-1 was increased in patients with chronic liver disease, reflecting the liver TIMP-1 level, and that it is useful for assessing liver fibrosis. An enzyme immunoassay for TIMP-2 is now available. In this study, we examined the clinical usefulness of this serum TIMP-2 test for liver fibrosis in patients with chronic liver disease, in comparison with the serum TIMP-1 test. The serum TIMP-2 concentration was 61 +/- 13 ng/ml in healthy controls (n = 32), and 18% higher in the group of chronic active hepatitis (CAH) patients (n = 34), 64% higher in the liver cirrhosis (LC) group (n = 33) and 44% higher in the hepatocellular carcinoma (HCC) group (n = 61), and similar to the control level in the chronic persistent hepatitis (CPH) group (n = 23). In contrast, the serum TIMP-1 concentration was 155 +/- 17 ng/ml in the healthy controls, 18% higher in CPH, 35% in CAH, 63% higher in LC and 92% higher in HCC. The serum TIMP-2 level was related to the histological degrees of both periportal necrosis and liver fibrosis, as well as to the serum TIMP-1 level. However, the relationships for TIMP-2 were weaker compared to those of serum TIMP-1. These results suggest that compared to the serum TIMP-1 level, changes in the serum TIMP-2 level in chronic liver disease are less liver-specific, and the serum TIMP-2 level is less useful in the assessment of liver fibrosis in chronic liver disease.


Journal of Hepatology | 1999

Clinical usefulness of serum matrix metalloproteinase-2 concentration in patients with chronic viral liver disease

Yoshikazu Murawaki; Sadako Yamada; Yujiro Ikuta; Hironaka Kawasaki

BACKGROUND/AIMS The production of matrix metalloproteinase (MMP)-2 was reported to be increased in chronically diseased livers. Our aims in the present study were to elucidate the clinical usefulness of the serum MMP-2 concentration in chronic viral liver disease. METHODS We measured serum MMP-2 concentrations with a sandwich enzyme immunoassay in 62 patients with chronic hepatitis, 35 patients with liver cirrhosis, 55 patients with hepatocellular carcinoma and 24 healthy individuals. The assay detects proMMP-2 and proMMP-2 complexed with tissue inhibitor of metalloproteinase-2, but not active forms of MMP-2. The liver MMP-2 content was also measured in autopsied cirrhotic and non-cirrhotic livers. Gelatin zymography and gel filtration chromatography were carried out using the serum. RESULTS The serum MMP-2 concentration was significantly increased in the liver cirrhosis and hepatocellular carcinoma patients, but not in the patients with chronic hepatitis. There was no significant difference in the serum MMP-2 level between the liver cirrhosis and hepatocellular carcinoma groups. In the patients with chronic viral liver disease, serum MMP-2 concentration showed the best correlation with the degree of liver fibrosis and with serum hyaluronate level. The zymography of serum showed the majority of MMP-2 in serum exists as a proMMP-2. The chromatography of serum revealed a single peak at the position of about 90 kDa corresponding to an MMP-2 complexed with tissue inhibitor of metalloproteinases-2. The liver MMP-2 content was markedly increased in the cirrhotic livers compared with the non-cirrhotic livers, and was positively correlated with the liver collagen content. When investigating the utility of the serum MMP-2 test for differentiating liver cirrhosis from chronic hepatitis, the utility of serum MMP-2 was equal to that of serum hyaluronate, which is known as the best current test for diagnosing liver cirrhosis. CONCLUSIONS The serum MMP-2 concentration reflects mainly the amount of proMMP-2 complexed with tissue inhibitor of metalloproteinase-2. The serum MMP-2 level was markedly increased in cirrhotic patients, and may be explained by an overproduction in the cirrhotic liver. In the clinical state, the measurement of serum MMP-2 was as useful a test for diagnosing liver cirrhosis as is the serum hyaluronate level.


Journal of Gastroenterology and Hepatology | 1998

Plasma transforming growth factor‐β1 concentrations in patients with chronic viral hepatitis

Yoshikazu Murawaki; Yuuko Nishimura; Yujiro Ikuta; Youko Idobe; Yukisato Kitamura; Hironaka Kawasaki

Transforming growth factor (TGF)‐β1 is an important cytokine involved in the pathobiology of tissue fibrosis through its stimulation of the production of, and inhibition of the degradation of, extracellular matrix proteins. We examined the clinical usefulness of plasma TGF‐β1 concentration as a marker of fibrogenesis in patients with chronic viral hepatitis. Thirty‐five patients, 11 with minimal chronic hepatitis, 14 with mild chronic hepatitis and 10 with moderate chronic hepatitis and 20 healthy subjects were studied. Transforming growth factor‐β1 concentrations in platelet‐poor plasma were measured with a TGF‐β1 enzyme‐linked immunosorbent assay system kit after acid‐ethanol extraction. Plasma TGF‐β1 levels were significantly elevated in patients with mild and moderate chronic hepatitis, but not in those with minimal chronic hepatitis, compared with the levels in the controls. Plasma TGF‐β1 levels were increased in parallel with the histological degree of necroinflammation and of liver fibrosis. Plasma TGF‐β1 levels were positively correlated with blood levels of procollagen type III N‐peptide, and 7S fragment and central triple‐helix of type IV collagen. These results suggest that plasma TGF‐β1 level is a useful marker in assessing the situation of liver active fibrogenesis in patients with chronic viral hepatitis.


Journal of Hepatology | 1995

Serum markers for connective tissue turnover in patients with chronic hepatitis B and chronic hepatitis C: A comparative analysis

Yoshikazu Murawaki; Yujiro Ikuta; Yuuko Nishimura; Masahiko Koda; Hironaka Kawasaki

BACKGROUND/AIMS Clinical and pathological differences between chronic hepatitis B and chronic hepatitis C have now been established. METHODS To compare hepatic connective tissue metabolism in chronic hepatitis B and C, we determined serum levels of prolyl 4-hydroxylase beta-subunit, procollagen III aminoterminal peptide, type IV collagen 7S domain, the central helix region of type IV collagen, tissue inhibitor of metalloproteinase, and hyaluronan in 55 patients with chronic hepatitis B and 83 patients with chronic hepatitis C. RESULTS There were no significant differences in the above markers for connective tissue turnover between the chronic hepatitis B group and the chronic hepatitis C group. CONCLUSIONS These results suggest that the accelerated connective tissue metabolism observed in chronic viral hepatitis is independent of the causative virus.


Journal of Hepatology | 2000

Changes in serum tissue inhibitor of matrix metalloproteinase-1 after interferon alpha treatment in chronic hepatitis C.

Akeri Mitsuda; Takeaki Suou; Yujiro Ikuta; Hironaka Kawasaki

BACKGROUND/AIMS The aim of this study was to evaluate the effect of interferon alpha on the metabolism of hepatic fibrosis in chronic hepatitis C, monitoring serum tissue inhibitor of matrix metalloproteinase-1(TIMP-1) and N-terminal propeptide of type III procollagen (PIIINP) reflecting fibrolysis and fibrogenesis, respectively. METHODS Serum levels of TIMP-1 and PIIINP were serially measured in 112 treated and 31 untreated patients with chronic hepatitis C during and after interferon alpha treatment. Furthermore, the relationships between these serum markers and the grades of hepatic fibrosis after interferon therapy were also investigated. RESULTS Serum pretreatment levels of TIMP-1 and PIIINP in non-responders were significantly higher than those in sustained and transient responders, but these levels were not different in the latter two groups. Serum TIMP-1 levels decreased significantly during and after treatment in sustained responders, and decreased temporarily at the end of treatment in transient responders, although these levels were unchanged during and after treatment in non-responders and untreated patients. In contrast, serum PIIINP levels decreased significantly during and after treatment in all treated groups, but were unchanged in untreated patients. Histological examination 12 months after interferon was completed demonstrated that hepatic fibrosis improved in sustained responders and was unchanged in transient and non-responders, but progressed in untreated patients. CONCLUSION These results suggest that interferon alpha treatment of chronic hepatitis C may improve hepatic fibrosis in sustained responders by the acceleration of fibrolysis as well as the inhibition of fibrogenesis, and that it may suppress the progression of hepatic fibrosis in non-sustained responders by the inhibition of fibrogenesis.

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