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Dive into the research topics where Kenya Yamanaka is active.

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Featured researches published by Kenya Yamanaka.


Journal of Hepatology | 2011

Proliferative activity in hepatocellular carcinoma is closely correlated with glucose metabolism but not angiogenesis

Koji Kitamura; Etsuro Hatano; Tatsuya Higashi; Masato Narita; Satoru Seo; Yuji Nakamoto; Kenya Yamanaka; Hiromitsu Nagata; Kojiro Taura; Kentaro Yasuchika; Takashi Nitta; Shinji Uemoto

BACKGROUND & AIMS This study investigated the relationship between tumor proliferative activity and the grade of tumor glucose metabolism or angiogenesis in hepatocellular carcinoma (HCC). METHODS The study was performed as a retrospective analysis of 63 patients with HCC who underwent fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) as a preoperative examination prior to liver resection. Tumor proliferative activity was evaluated by the Ki-67 labeling index (LI). The grade of tumor glucose metabolism was evaluated by measuring the protein expression level of glucose transporter (GLUT)-1, expression level of pyruvate kinase type M2 (PKM2) mRNA, and FDG uptake. The grade of tumor angiogenesis was evaluated by the protein expression level of vascular endothelial growth factor (VEGF) and tumor microvessel density. RESULTS All patients were divided into tertiles according to the Ki-67 LI: the low LI group (n = 21), the intermediate LI group (n = 21), and the high LI group (n = 21). The high LI group showed a tendency to have advanced tumor stage, and lower disease-free survival and overall survival rates than the low LI and the intermediate LI groups. The expression grade of GLUT-1, PKM2 mRNA, and FDG uptake gradually increased with the Ki-67 LI. On the other hand, the protein expression grade of VEGF and microvessel density was paradoxically decreased with the Ki-67 LI. CONCLUSIONS These data suggest that (1) the proliferative activity of a resected specimen predicted the prognosis in patients with HCC; (2) the proliferative activity was closely correlated with the glucose metabolism, but not with angiogenesis.


Cancer Medicine | 2013

Therapeutic potential and adverse events of everolimus for treatment of hepatocellular carcinoma – systematic review and meta-analysis

Kenya Yamanaka; Marius Petrulionis; Shibo Lin; Chao Gao; Uwe Galli; Susanne Richter; Susanne Winkler; Philipp Houben; Daniel Schultze; Etsuro Hatano; Peter Schemmer

Everolimus is an orally administrated mammalian target of rapamycin (mTOR) inhibitor. Several large‐scale randomized controlled trials (RCTs) have demonstrated the survival benefits of everolimus at the dose of 10 mg/day for solid cancers. Furthermore, mTOR‐inhibitor‐based immunosuppression is associated with survival benefits for patients with hepatocellular carcinoma (HCC) who have received liver transplantation. However, a low rate of tumor reduction and some adverse events have been pointed out. This review summarizes the antitumor effects and adverse events of everolimus and evaluates its possible application in advanced HCC. For the meta‐analysis of adverse events, we used the RCTs for solid cancers. The odds ratios of adverse events were calculated using the Peto method. Manypreclinical studies demonstrated that everolimus had antitumor effects such as antiproliferation and antiangiogenesis. However, some differences in the effects were observed among in vivo animal studies for HCC treatment. Meanwhile, clinical studies demonstrated that the response rate of single‐agent everolimus was low, though survival benefits could be expected. The meta‐analysis revealed the odds ratios (95% confidence interval [CI]) of stomatitis: 5.42 [4.31–6.73], hyperglycemia: 3.22 [2.37–4.39], anemia: 3.34 [2.37–4.67], pneumonitis: 6.02 [3.95–9.16], aspartate aminotransferase levels: 2.22 [1.37–3.62], and serum alanine aminotransferase levels: 2.94 [1.72–5.02], respectively. Everolimus at the dose of 10 mg/day significantly increased the risk of the adverse events. In order to enable its application to the standard conventional therapies of HCC, further studies are required to enhance the antitumor effects and manage the adverse events of everolimus.


Journal of Gastroenterology and Hepatology | 2009

Dai-kenchu-to attenuates rat sinusoidal obstruction syndrome by inhibiting the accumulation of neutrophils in the liver.

Masato Narita; Etsuro Hatano; Nobuyuki Tamaki; Kenya Yamanaka; Atsuko Yanagida; Hiromitsu Nagata; Hiroyuki Asechi; Yasutsugu Takada; Iwao Ikai; Shinji Uemoto

Background and Aim:  Sinusoidal obstruction syndrome (SOS) is drug‐induced liver injury that occurs in patients who receive hematopoietic cell transplantation and oxaliplatin‐contained chemotherapy. The aim of study was to investigate the pharmacological treatment of SOS using a traditional Japanese medicine, Dai‐kenchu‐to (DKT).


Liver Transplantation | 2011

Olprinone attenuates excessive shear stress through up‐regulation of endothelial nitric oxide synthase in a rat excessive hepatectomy model

Kenya Yamanaka; Etsuro Hatano; Masato Narita; Koji Kitamura; Atsuko Yanagida; Hiroyuki Asechi; Hiromitsu Nagata; Kojiro Taura; Takashi Nitta; Shinji Uemoto

After extended hepatectomy, excessive shear stress in the remnant liver causes postoperative liver failure. Olprinone (OLP), a selective phosphodiesterase inhibitor, has been reported to improve microcirculation and attenuate inflammation. The aim of this study was to investigate the effects of OLP on shear stress in rats with an excessive hepatectomy (EHx) model. In this study, EHx comprised 90% hepatectomy with ligation of the left and right Glissons sheaths in Lewis rats. OLP or saline was intraperitoneally administered with an osmotic pump 48 hours before EHx. To evaluate the shear stress, we measured the portal vein (PV) pressure. We also assessed sinusoidal endothelial cell injury by immunohistochemistry and electron microscopy. Furthermore, we assessed apoptosis in the liver with the terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick‐end labeling method. Treatment with OLP up‐regulated hepatic endothelial nitric oxide synthase (eNOS) expression. The increase in the PV pressure due to Glissons sheath ligation was attenuated in OLP‐treated rats during a 30‐minute period after ligation. Treatment with OLP preserved sinusoidal endothelial cells and reduced apoptosis in the remnant liver. The probability of survival in the OLP‐treated rats was significantly better than that in the controls (33.3% versus 13.3%). Furthermore, the postoperative eNOS activity in the OLP‐treated rats was higher than that in the controls. The administration of Nω‐nitro‐l‐arginine methyl ester to OLP‐treated rats eliminated the effects of OLP on PV pressure and survival after EHx. Therefore, we concluded that OLP attenuates excessive shear stress through the up‐regulation of eNOS and improves the survival rate after EHx. Liver Transpl 17:60–69, 2011.


Clinical Trials | 2012

An eClinical trial system for cancer that integrates with clinical pathways and electronic medical records

Keiichi Yamamoto; Kenya Yamanaka; Etsuro Hatano; Eriko Sumi; Takamichi Ishii; Kojiro Taura; Kohta Iguchi; Satoshi Teramukai; Masayuki Yokode; Shinji Uemoto; Masanori Fukushima

Background Various information technologies currently are used to improve the efficiency of clinical trials. However, electronic medical records (EMRs) are not yet linked to the electronic data capture (EDC) system. Therefore, the data must be extracted from medical records and transcribed to the EDC system. Clinical pathways are planned process patterns that are used in routine clinical practice and are easily applicable to the medical care and evaluation defined in a trial protocol. However, few clinical pathways are intended to increase the efficiency of clinical trials. Purpose Our purpose is to describe the design and development of a new clinical trial process model that enables the primary use of EMRs in clinical trials by integrating clinical pathways and EMRs. Methods We designed a new clinical trial model that uses EMR data directly in clinical trials and developed a system to follow this model. We applied the system to an investigator-initiated clinical trial and examined whether all data were extracted correctly. At the protocol development stage, our model measures endpoints based on clinical pathways with the same diagnosis. Next, medical record descriptions and the format of the statistical data are defined. According to these observations, screens for entry of data, which are used both in clinical practice and for study, are prepared into EMRs with an EMR template, and screens are prepared for data checks on our EMR retrieval system (ERS). In an actual trial, patients are registered and randomly assigned to a protocol treatment. The protocol treatment is executed according to clinical pathways, and the data are recorded to EMRs using EMR templates. The data are checked by a local data manager using reports created by the ERS. After edit checks and corrections, the data are extracted by the ERS, archived in portable document format (PDF) with an electronic signature, and transferred in comma-separated values (CSV) format to a coordinating centre. At the coordinating centre, the data are checked, integrated, and made available for a statistical analysis. Results We verified that the data could be extracted correctly and found no unexpected problems. Limitation To execute clinical trials in our system, the EMR template and efficient ERSs are required. Additionally, to execute multi-institutional clinical trials, it is necessary to create templates appropriate for EMRs at all participating sites and for the coordinating centre to validate local templates and procedures. Conclusion We proposed and pilot tested a new eClinical trial model. Because our model is integrated with routine documentation of clinical practice and clinical trials, redundant data entries were avoided and the burden on the investigator was minimised. The reengineering of the clinical trial process would facilitate the establishment of evidence in the future.


PLOS ONE | 2015

A systematic review of pharmacological treatment options used to reduce ischemia reperfusion injury in rat liver transplantation.

Kenya Yamanaka; Philipp Houben; Helge Bruns; Daniel Schultze; Etsuro Hatano; Peter Schemmer

Background Although animal studies models are frequently used for the purpose of attenuating ischemia reperfusion injury (IRI) in liver transplantation (LT), many of pharmacological agents have not become part of clinical routine. Methods A search was performed using the PubMed database to identify agents, from which 58 articles containing 2700 rat LT procedures were selected. The identified pharmacological agents were categorized as follows: I - adenosine agonists, nitric oxide agonists, endothelin antagonists, and prostaglandins, II – Kupffer cell inactivator, III - complement inhibiter, IV - antioxidant, V - neutrophil inactivator, VI -anti-apoptosis agent, VII - heat shock protein and nuclear factor kappa B inducer, VIII - metabolic agent, IX - traditional Chinese medicine, and X - others. Meta-analysis using 7-day-survival rate was also performed with Mantel-Haenszels Random effects model. Results The categorization revealed that the rate of donor-treated experiments in each group was highest for agents from Group II (70%) and VII (71%), whereas it was higher for agents from Group V (83%) in the recipient-treated experiments. Furthermore, 90% of the experiments with agents in Group II provided 7-day-survival benefits. The Risk Ratio (RR) of the meta-analysis was 2.43 [95% CI: 1.88-3.14] with moderate heterogeneity. However, the RR of each of the studies was too model-dependent to be used in the search for the most promising pharmacological agent. Conclusion With regard to hepatic IRI pathology, the categorization of agents of interest would be a first step in designing suitable multifactorial and pleiotropic approaches to develop pharmacological strategies.


Hepatology Research | 2011

Comparative study of cisplatin and epirubicin in transcatheter arterial chemoembolization for hepatocellular carcinoma.

Kenya Yamanaka; Etsuro Hatano; Masato Narita; Kojiro Taura; Kentaro Yasuchika; Takashi Nitta; Shigeki Arizono; Hiroyoshi Isoda; Toshiya Shibata; Iwao Ikai; Tosiya Sato; Shinji Uemoto

Aim:  Transcatheter arterial chemoembolization (TACE) is an established treatment for unresectable hepatocellular carcinoma (HCC). However, it is unclear which chemotherapeutic agent should be selected for TACE. The aim of this study was to compare the efficacy of cisplatin (CDDP) with that of epirubicin (EPI) in TACE for patients with unresectable or relapsed HCC.


Hepatology Research | 2014

Effects of oral intake of hydrogen water on liver fibrogenesis in mice

Yukinori Koyama; Kojiro Taura; Etsuro Hatano; Kazutaka Tanabe; Gen Yamamoto; Kojiro Nakamura; Kenya Yamanaka; Koji Kitamura; Masato Narita; Hiromitsu Nagata; Atsuko Yanagida; Taku Iida; Keiko Iwaisako; Hikohito Fujinawa; Shinji Uemoto

Liver fibrosis is the universal consequence of chronic liver diseases. Sustained hepatocyte injury initiates an inflammatory response, thereby activating hepatic stellate cells, the principal fibrogenic cells in the liver. Reactive oxygen species are involved in liver injury and are a promising target for treating liver fibrosis. Hydrogen water is reported to have potential as a therapeutic tool for reactive oxygen species‐associated disorders. This study aimed to investigate the effects of hydrogen water on liver fibrogenesis and the mechanisms underlying these effects.


Digestive Surgery | 2015

Validation of the Conventional Resection Criteria in Patients with Hepatocellular Carcinoma in Terms of the Incidence of Posthepatectomy Liver Failure and Long-Term Prognosis

Kohta Iguchi; Etsuro Hatano; Kenya Yamanaka; Shiro Tanaka; Kojiro Taura; Shinji Uemoto

Background/Aims: Resection criteria in hepatocellular carcinoma (HCC) should be established based on the risk of posthepatectomy liver failure (PHLF) and the survival benefit from hepatectomy. This study aimed at verifying the validity of the conventional criteria regarding the incidence of PHLF and the long-term prognosis of HCC patients. Methods: A retrospective study was performed on 265 patients who underwent major hepatectomy. Makuuchis criteria and the future liver remnant plasma clearance rate of indocyanine green (ICGK-rem) ≥0.05 criterion were evaluated. Results: A total of 107 and 158 patients were within and beyond Makuuchis criteria, respectively. Makuuchis criteria were associated with the incidence of PHLF (p = 0.03) but not with its severity (p = 0.12). No differences in disease-free survival (DFS) or overall survival (OS) were observed between the groups (p = 0.75 and p = 0.94, respectively). Using the ICGK-rem ≥0.05 criterion, 223 and 42 patients were within and beyond the criterion, respectively. ICGK-rem was correlated with both the incidence of PHLF (p = 0.002) and its severity (p = 0.03). No differences in DFS or OS were observed between the groups (p = 0.75 and p = 0.29, respectively). Conclusions: Strict criteria are likely to preclude some patients from obtaining the greater survival benefits of hepatectomy. New criteria that consider patient prognosis are needed.


Trials | 2013

The correlation between the number of eligible patients in routine clinical practice and the low recruitment level in clinical trials: a retrospective study using electronic medical records

Eriko Sumi; Satoshi Teramukai; Keiichi Yamamoto; Motohiko Satoh; Kenya Yamanaka; Masayuki Yokode

BackgroundA number of clinical trials have encountered difficulties enrolling a sufficient number of patients upon initiating the trial. Recently, many screening systems that search clinical data warehouses for patients who are eligible for clinical trials have been developed. We aimed to estimate the number of eligible patients using routine electronic medical records (EMRs) and to predict the difficulty of enrolling sufficient patients prior to beginning a trial.MethodsInvestigator-initiated clinical trials that were conducted at Kyoto University Hospital between July 2004 and January 2011 were included in this study. We searched the EMRs for eligible patients and calculated the eligible EMR patient index by dividing the number of eligible patients in the EMRs by the target sample size. Additionally, we divided the trial eligibility criteria into corresponding data elements in the EMRs to evaluate the completeness of mapping clinical manifestation in trial eligibility criteria into structured data elements in the EMRs. We evaluated the correlation between the index and the accrual achievement with Spearmans rank correlation coefficient.ResultsThirteen of 19 trials did not achieve their original target sample size. Overall, 55% of the trial eligibility criteria were mapped into data elements in EMRs. The accrual achievement demonstrated a significant positive correlation with the eligible EMR patient index (r = 0.67, 95% confidence interval (CI), 0.42 to 0.92). The receiver operating characteristic analysis revealed an eligible EMR patient index cut-off value of 1.7, with a sensitivity of 69.2% and a specificity of 100.0%.ConclusionsOur study suggests that the eligible EMR patient index remains exploratory but could be a useful component of the feasibility study when planning a clinical trial. Establishing a step to check whether there are likely to be a sufficient number of eligible patients enables sponsors and investigators to concentrate their resources and efforts on more achievable trials.

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