Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Koji Umeshita is active.

Publication


Featured researches published by Koji Umeshita.


The Lancet | 2003

Operative morbidity of living liver donors in Japan

Koji Umeshita; Kenji Fujiwara; Kendo Kiyosawa; Masatoshi Makuuchi; Susumu Satomi; Keizo Sugimachi; Koichi Tanaka; Morito Monden

BACKGROUND Deaths of living liver donors have been reported in western countries, whereas the morbidity and mortality of such donors in Japan, one of the leading countries for living liver transplantation, have not been reported in detail. We aimed to review the operative morbidity and mortality of such donors in Japan. METHODS 1853 donors of 1852 living liver transplants done in 46 liver transplant centres, and registered in the database of the Japanese Liver Transplantation Society, were assessed for eight donor-related factors of morbidity and mortality. Data for 1841 donors were analysed. FINDINGS No perioperative mortality was recorded since inception of the liver transplantation programme in Japan from Nov 13, 1989, to April 11, 2002. 244 postoperative complications were reported in 228 (12%) donors. The frequency of complications was significantly higher in donors of the right liver lobe than in those involving the lateral segment, and left lobe graft (p<0.0001, and p<0.0001, respectively). Postoperative hospital stay was significantly longer in donors of the right lobe (mean 19.7 [SD 13.0]) than in those of the lateral segment (14.2 [7.6]), left lobe (14.0 [6.5]), and left lobe and caudate lobe (16.3 [12.1]). Re-operation related to donor hepatectomy was done in 23 donors. INTERPRETATION By contrast with western countries, no perioperative mortality was recorded in living liver donors in Japan. However, a proportion of these donors developed serious complications. This morbidity should be reduced to maintain zero mortality in living liver donors.


Journal of Hepatology | 2012

Circulating microRNA-21 as a novel biomarker for hepatocellular carcinoma.

Yoshito Tomimaru; Hidetoshi Eguchi; Hiroaki Nagano; Hiroshi Wada; Shogo Kobayashi; Shigeru Marubashi; Masahiro Tanemura; Akira Tomokuni; Ichiro Takemasa; Koji Umeshita; Tatsuya Kanto; Yuichiro Doki; Masaki Mori

BACKGROUND & AIMS Several groups have reported the significance of circulating microRNA as a biochemical marker of cancer. To our knowledge, however, there are no reports on the significance of circulating microRNA in hepatocellular carcinoma. The aim of this study was to evaluate the significance of plasma microRNA-21 level as a biochemical marker for hepatocellular carcinoma. METHODS Plasma microRNA-21 level was measured by qRT-PCR in 10 patients before and after curative resection of hepatocellular carcinoma. Plasma microRNA-21 was also compared in other groups of: 126 patients with hepatocellular carcinoma, 30 patients with chronic hepatitis, and 50 healthy volunteers. The power of microRNA-21 in differentiating hepatocellular carcinoma from chronic hepatitis or from healthy volunteers was compared to that of α-fetoprotein. RESULTS In the 10-patient group, plasma microRNA-21 levels significantly diminished after surgery compared with the pre-operative values (p=0.0125). Plasma microRNA-21 level in the 126 patients with hepatocellular carcinoma was significantly higher than in patients with chronic hepatitis and healthy volunteers (p<0.0001, p<0.0001, respectively). ROC analysis of plasma microRNA-21 yielded an AUC of 0.773 with 61.1% sensitivity and 83.3% specificity when differentiating hepatocellular carcinoma from chronic hepatitis, and an AUC of 0.953 with 87.3% sensitivity and 92.0% specificity when differentiating hepatocellular carcinoma from healthy volunteers. Both sets of values were superior to α-fetoprotein and improved for the combination of microRNA-21 and α-fetoprotein. CONCLUSIONS Plasma microRNA-21 level is a promising biochemical marker for hepatocellular carcinoma.


Clinical Cancer Research | 2004

Prognostic Significance of Activated Akt Expression in Pancreatic Ductal Adenocarcinoma

Shinji Yamamoto; Yasuhiko Tomita; Yoshihiko Hoshida; Takaya Morooka; Hiroaki Nagano; Keizo Dono; Koji Umeshita; Masato Sakon; Osamu Ishikawa; Hiroaki Ohigashi; Shoji Nakamori; Morito Monden; Katsuyuki Aozasa

Purpose: Akt is a serine/threonine kinase that plays a central role in tumorigenesis. Among the members of Akt family, Akt2 is associated with the development of human cancers. The present study was designed to clarify the prognostic significance of Akt2 and activated Akt expression in pancreatic ductal adenocarcinoma (PDAC). In addition, activated extracellular signal-regulated kinase 1 and 2 (ERK1/2) and the proliferation activity of tumor cells detected by Ki-67 immunohistochemistry were examined. Experimental Design: Immunohistochemical analysis was performed on paraffin-embedded specimens from 65 patients with PDAC; 36 males and 29 females with ages ranging from 48 to 79 years (median, 66 years) of age. Expression levels of Akt2, phosphorylated Akt (p-Akt), and phosphorylated ERK 1/2 (p-ERK 1/2) were categorized as either weaker (low intensity) or equal to stronger (high intensity) compared with those in the endothelial cells of the same specimens. For Ki-67 immunohistochemistry, cases were divided into two groups: level 1, Ki-67 labeling index (LI), <20%; level 2, Ki-67 LI, ≥20%. Results: Twenty-six (42.6%), 28 (45.9%), 39 (63.9%), and 46 (75.4%) of the tumors showed high intensity of Akt2, p-Akt, and p-ERK 1/2 expression, and Ki-67 LI level 2, respectively. A significant positive correlation was observed between Akt2 and p-Akt expression (P < 0.01). Multivariate analysis revealed that p-Akt expression, Ki-67 LI, and histological differentiation are independent prognosticators for PDAC. Conclusions: p-Akt expression is a significant prognostic indicator for PDAC. Inhibition of Akt is a possible molecular approach for treatment of PDAC.


International Journal of Cancer | 2007

Involvement of ribonucleotide reductase M1 subunit overexpression in gemcitabine resistance of human pancreatic cancer.

Nakahira S; Shoji Nakamori; Masanori Tsujie; Yuji Takahashi; Jiro Okami; Shinichi Yoshioka; Makoto Yamasaki; Shigeru Marubashi; Ichiro Takemasa; Atsushi Miyamoto; Yutaka Takeda; Hiroaki Nagano; Keizo Dono; Koji Umeshita; Masato Sakon; Morito Monden

Pancreatic cancer is the most lethal of all solid tumors partially because of its chemoresistance. Although gemcitabine is widely used as a first selected agent for the treatment of this disease despite low response rate, molecular mechanisms of gemcitabine resistance in pancreatic cancer still remain obscure. The aim of this study is to elucidate the mechanisms of gemcitabine resistance. The 81‐fold gemcitabine resistant variant MiaPaCa2‐RG was selected from pancreatic cancer cell line MiaPaCa2. By microarray analysis between MiaPaCa2 and MiaPaCa2‐RG, 43 genes (0.04%) were altered expression of more than 2‐fold. The most upregulated gene in MiaPaCa2‐RG was ribonucleotide reductase M1 subunit (RRM1) with 4.5‐fold up‐regulation. Transfection with RRM1‐specific RNAi suppressed more than 90% of RRM1 mRNA and protein expression. After RRM1‐specific RNAi transfection, gemcitabine chemoresistance of MiaPaCa2‐RG was reduced to the same level of MiaPaCa2. The 18 recurrent pancreatic cancer patients treated by gemcitabine were divided into 2 groups by RRM1 levels. There was a significant association between gemcitabine response and RRM1 expression (p = 0.018). Patients with high RRM1 levels had poor survival after gemcitabine treatment than those with low RRM1 levels (p = 0.016). RRM1 should be a key molecule in gemcitabine resistance in human pancreatic cancer through both in vitro and clinical models. RRM1 may have the potential as predictor and modulator of gemcitabine treatment.


Transplantation | 2009

Donor complications associated with living donor liver transplantation in Japan.

Yasuhiko Hashikura; Takafumi Ichida; Koji Umeshita; Seiji Kawasaki; Masashi Mizokami; Satoshi Mochida; Katsuhiko Yanaga; Morito Monden; Kendo Kiyosawa

Background. The Japanese Liver Transplantation Society presented its first report on donor morbidity in 2003. The Society has been continuing to survey outcomes in living liver donors in Japan. Methods. By using a uniform comprehensive medical record review process, data were collected on 3565 living liver donors who had donated grafts by the end of December 2006 at 38 Japanese centers. Results. Preoperative problems were reported in 2 donors, intraoperative problems in 27, and postoperative complications in 270. In total, 299 donors (8.4%) suffered complications related to liver donation. Postoperative complications included biliary complications in 3.0%, reoperation in 1.3%, severe after-effects in two (0.06%), and death (apparently related to donor surgery) in one donor (0.03%). The incidence of postoperative complications in left and right lobe donors was 8.7% and 9.4%, respectively. Conclusions. The accumulated experience indicates a reduction in the incidence of donor complications, especially for right lobe resection. One donor death and two cases of severe after effects related to liver donation have been reported during 18 years of living donor liver transplantation experience in Japan.


Gastroenterology | 2003

JTE-522, a cyclooxygenase-2 inhibitor, is an effective chemopreventive agent against rat experimental liver fibrosis1 ☆

Hirofumi Yamamoto; Motoi Kondo; Shoji Nakamori; Hiroaki Nagano; Ken—ichi Wakasa; Yurika Sugita; Jin Chang—de; Shogo Kobayashi; Bazarragchaa Damdinsuren; Keizo Dono; Koji Umeshita; Mitsugu Sekimoto; Masato Sakon; Nariaki Matsuura; Morito Monden

BACKGROUND & AIMS The aim of this study was to assess the effects of cyclooxygenase (COX)-2 inhibition on rat experimental liver fibrogenesis. METHODS We investigated the inhibitory effects of a selective COX-2 inhibitor, JTE-522, on liver fibrosis induced by a choline-deficient, l-amino acid-defined diet (CDAA). Inhibitory effect was also tested in a second model of thioacetamide (TAA)-induced liver fibrosis. RESULTS CDAA induced liver fibrosis and preneoplastic foci at 12 weeks and cirrhosis at 36 weeks. Hepatocellular carcinoma was noted in 13 of 15 rats (87%). JTE-522 significantly inhibited fibrosis and development of preneoplastic lesions in a dose-dependent manner and completely inhibited generation of cirrhosis and hepatocellular carcinoma at both low and high doses (10 and 30 mg/kg body wt/day, respectively). JTE-522 administrated only from 12 weeks to 36 weeks also prevented cirrhosis and formation of hepatocellular carcinoma. JTE-522 itself did not cause local or systemic gross or histopathologic changes at 36 weeks. Mechanistic studies indicated that the CDAA model displayed up-regulation of several biomarkers, including COX-2, arachidonate metabolite (prostaglandin E(2)), serum aspartate aminotransferase, and c-myc expression. The model also showed an increased proportion of activated hepatic stellate cells, proliferating cell nuclear antigen index, and CD45-positive inflammatory cells in the liver. JTE-522 effectively diminished these changes. JTE-522 exhibited similar antifibrosis effects in the TAA model. CONCLUSIONS Our results suggest that COX-2 is involved in CDAA- and TAA-induced liver fibrosis. Our data also indicate that JTE-522 is a potent chemopreventive agent of rat liver fibrosis with low toxicity.


Journal of Clinical Oncology | 2003

Elevated Expression of Valosin-Containing Protein (p97) in Hepatocellular Carcinoma Is Correlated With Increased Incidence of Tumor Recurrence

Shinji Yamamoto; Yasuhiko Tomita; Shoji Nakamori; Yoshihiko Hoshida; Hiroaki Nagano; Keizo Dono; Koji Umeshita; Masato Sakon; Morito Monden; Katsuyuki Aozasa

PURPOSE Valosin-containing protein (VCP; also known as p97) has been shown to be associated with antiapoptotic function and metastasis via activation of the nuclear factor-kappaB signaling pathway. In this study, association of VCP expression with recurrence of hepatocellular carcinoma (HCC) and patient survival was examined. PATIENTS AND METHODS VCP expression in 170 patients (139 male and 31 female) with ages ranging from 31 to 81 years (median, 61 years) was analyzed by quantitative reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry, in which staining intensity in tumor cells was categorized as weaker (level 1) or equal to or stronger (level 2) than that in endothelial cells. RESULTS Immunohistochemically, 57 patients (35.2%) showed level 1, and 105 patients (64.8%) showed level 2, VCP expression. Quantitative RT-PCR analysis revealed higher VCP mRNA expression in level 2 patients (n = 7) than level 1 (n = 4) (P <.05). Patients with VCP-level 2 HCC showed higher rate of portal vein invasion in the tumor (P <.01) and poorer disease-free and overall survival (P <.0001 and P <.05, respectively) compared with level 1 patients. Multivariate analysis revealed VCP expression level, tumor multiplicity, and degree of fibrosis in the noncancerous liver tissue to be independent prognosticators for disease-free and overall survival. VCP level was an indicator for disease-free survival in each early- (I and II) and advanced- (III and IV) stage group of pathologic tumor-node-metastasis classification (P <.001 and P <.01, respectively). CONCLUSION VCP expression level has prognostic significance for disease-free and overall survival of patients with HCC.


Liver International | 2006

Expression pattern of angiogenic factors and prognosis after hepatic resection in hepatocellular carcinoma: importance of angiopoietin‐2 and hypoxia‐induced factor‐1a

Hiroshi Wada; Hiroaki Nagano; Hirofumi Yamamoto; Yubo Yang; Motoi Kondo; Hideo Ota; Masato Nakamura; Shinichi Yoshioka; Hitoshi Kato; Bazarragchaa Damdinsuren; Di Tang; Sigeru Marubashi; Atsushi Miyamoto; Yutaka Takeda; Koji Umeshita; Shoji Nakamori; Masato Sakon; Keizo Dono; Kenichi Wakasa; Morito Monden

Abstract: Background: Hepatocellular carcinoma (HCC) is a hypervascular tumor and angiogenesis plays an important role in its progression. Angiogenesis is regulated by a balance between pro and antiangiogenic molecules. The aim of this study was to investigate the expressions of angiogenic factors and elucidate their roles in angiogenesis in HCC.


Cancer | 2007

Interferon-α and 5-fluorouracil combination therapy after palliative hepatic resection in patients with advanced hepatocellular carcinoma, portal venous tumor thrombus in the major trunk, and multiple nodules

Hiroaki Nagano; Atsushi Miyamoto; Hiroshi Wada; Hideo Ota; Shigeru Marubashi; Yutaka Takeda; Keizo Dono; Koji Umeshita; Masato Sakon; Morito Monden

The authors reported previously the beneficial effects of interferon (IFN)‐α/5‐fluorouracil (5‐FU) combination therapy for patients with advanced hepatocellular carcinoma (HCC) who have tumor thrombi in the major portal branches. In this report, the authors describe the results from IFN/5‐FU chemotherapy for patients who underwent palliative hepatic resection for advanced HCC with tumor thrombus in the main trunk of the portal vein and multiple nodules in the whole liver. In addition, they evaluated the correlation between the response to such therapy and expression of IFN‐α type 2 receptor (IFNAR2).


Clinical Cancer Research | 2004

Partial Contribution of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)/TRAIL Receptor Pathway to Antitumor Effects of Interferon-α/5-Fluorouracil against Hepatocellular Carcinoma

Tameyoshi Yamamoto; Hiroaki Nagano; Masato Sakon; Hisashi Wada; Hidetoshi Eguchi; Motoi Kondo; Bazarragchaa Damdinsuren; Hideo Ota; Masato Nakamura; Hiroshi Wada; Shigeru Marubashi; Atsushi Miyamoto; Keizo Dono; Koji Umeshita; Shoji Nakamori; Hideo Yagita; Morito Monden

Purpose: Our purpose was to explore the contribution of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/TRAIL receptor pathway to antitumor effects of IFNα and 5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC). Experimental Design: Susceptibility of HCC cell lines to TRAIL and/or 5-FU was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effects of 5-FU, IFNα, or both on the expression of TRAIL receptors (R1, R2, R3, and R4) on HCC cells or TRAIL in peripheral blood mononuclear cells (PBMC) were examined by flow cytometry. IFNα-induced cytotoxic effects of PBMC on HCC cell lines were examined by 51Cr release assay. TRAIL expression in peripheral blood mononuclear cells and liver tissue from patients was examined by real-time reverse transcription-PCR or immunohistochemistry. Results: HLE and HepG2 were sensitive to TRAIL, but HuH7, PLC/PRF/5, and HLF were resistant. 5-FU had synergistic effect on TRAIL in HLF and additive effect in four other HCC cell lines. TRAIL receptors on HCC cells were up-regulated by 5-FU, and IFNα induced TRAIL on CD4+ T cells, CD14+ monocytes, and CD56+ NK cells. Treatment of effector cells by IFNα and target HCC cells by 5-FU enhanced the cytotoxicity of CD14+ monocytes and CD56+ NK cells against HCC cells via a TRAIL-mediated pathway. TRAIL mRNA overexpression was noted in PBMC of HCC patients who clinically responded to IFNα/5-FU combination therapy, and TRAIL+ mononuclear cells were found in cancer tissue of a responder. Conclusion: Our results suggest that modulation of TRAIL/TRAIL receptor-mediated cytotoxic pathway might partially contribute to the anti-HCC effect of IFNα and 5-FU combination therapy.

Collaboration


Dive into the Koji Umeshita's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge