Taiichi Wakiya

Dr. Taiichi Wakiya

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Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2017 in Anticancer Research
Verified
Journal Article
Open access
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TMTakuya Miura
Takuya Miura
TYTadashi Yoshizawa
Tadashi Yoshizawa
HHHideaki Hirai
Hideaki Hirai
HSHiroko Seino
Hiroko Seino
SMSatoko Morohashi
Satoko Morohashi
KHKenichi Hakamada
Kenichi Hakamada
Aim: The aim of this study was to examine the clinicopathological influence of tumor-infiltrating cluster of differentiation (CD) 163+ macrophages and CD8+ T-cells, and to clarify the prognostic effects of these cells in patients with invasive extrahepatic bile duct cancer (EHBC). Materials and Methods: The numbers of CD8+ T-cells in cancer cell nests and CD163+ macrophages in tumor stroma were evaluated using immunohistochemistry in 101 resected EHBC specimens. Correlations with clinicopathological variables and overall survival were analyzed. Results: Perihilar EHBC and perineural invasion were significantly associated with a low number of tumor-infiltrating CD8+ T-cells. Poorly- differentiated histology and nodal metastasis were significantly associated with a high number of tumor-infiltrating CD163+ macrophages. A combination of high number of CD8+ T-cells and low number of CD163+ macrophages was independently related to better overall survival in the whole patient cohort (hazard ratio=0.127, p<0.001) and in patients treated with adjuvant chemotherapy (hazard ratio=0.139, p=0.021). Conclusion: Infiltrating CD163+ macrophages in tumor stroma and CD8+ T-cells in cancer cell nests have a prognostic impact in patients with EHBC following resection and also after adjuvant chemotherapy.

1 January 2014 in World Journal of Gastroenterology
Verified
Journal Article
Open access
YSYukihiro Sanada
Yukihiro Sanada
KMKoshi Matsumoto
Koshi Matsumoto
TUTaizen Urahashi
Taizen Urahashi
YIYoshiyuki Ihara
Yoshiyuki Ihara
TWTaiichi Wakiya
Taiichi Wakiya
KMKoichi Mizuta
Koichi Mizuta
To assessed the clinical significance of protocol liver biopsy (PLB) in pediatric liver transplantation (LT). Between July 2008 and August 2012, 89 and 55 PLBs were performed in pediatric patients at two and five years after LT, respectively. We assessed the histopathological findings using the Metavir scoring system, including activity (A) and fibrosis (F), and we identified factors associated with scores of ≥ A1 and ≥ F1. Our results clarified the timing and effectiveness of PLB. The incidences of scores of ≥ A1 and ≥ F1 were 24.7% and 24.7%, respectively, at two years after LT and 42.3% and 34.5%, respectively, at five years. Independent risk factors in a multivariate analysis of a score of ≥ A1 at two years included ≥ 2 h of cold ischemic time, no acute cellular rejection and an alanine amino transaminase (ALT) level of ≥ 20 IU/L (P = 0.028, P = 0.033 and P = 0.012, respectively); however, no risk factors were identified for a score of ≥ F1. Furthermore, no independent risk factors associated with scores of ≥ A1 and ≥ F1 at five years were identified using multivariate analysis. A ROC curve analysis of ALT at two years for a score of ≥ A1 demonstrated the recommended cutoff value for diagnosing ≥ A1 histology to be 20 IU/L. The incidence of scores of ≥ A2 or ≥ F2 at two years after LT was 3.4% (three cases), and all patients had an absolute score of ≥ A2. In contrast to that observed for PLBs at five years after LT, the incidence of scores of ≥ A2 or ≥ F2 was 20.0% (11 cases), and all patients had an absolute score of ≥ F2. In all cases, the dose of immunosuppressants was increased after the PLB, and all ten patients who underwent a follow-up liver biopsy improved to scores of ≤ A1 or F1. PLB at two years after LT is an unnecessary examination, because the serum ALT level reflects portal inflammation. In addition, immunosuppressive therapy should be modulated to maintain the ALT concentration at a level less than 20 IU/L. PLB at five years is an excellent examination for the detection of early reversible graft fibrosis because no serum markers reflect this finding.

25 August 2010 in Transplant International
Verified
Journal Article
Open access
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YSYukihiro Sanada
Yukihiro Sanada
KMKoichi Mizuta
Koichi Mizuta
TYTomonori Yano
Tomonori Yano
WHWataru Hatanaka
Wataru Hatanaka
NONoriki Okada
Noriki Okada
HKHideo Kawarasaki
Hideo Kawarasaki
Bilioenteric anastomotic stricture after liver transplantation is still frequent and early detection and treatment is important. We established the management using double‐balloon enteroscopy (DBE) and evaluated the intractability for bilioenteric anastomotic stricture after pediatric living donor liver transplantation (LDLT). We underwent DBE at Jichi Medical University from May 2003 to July 2009 for 25 patients who developed bilioenteric anastomotic stricture after pediatric LDLT. The patients were divided into two types according to the degree of dilatation of the anastomotic sites before and after interventional radiology (IVR) using DBE. Type I is an anastomotic site macroscopically dilated to five times or more, and Type II is an anastomotic site dilated to less than five times. The rate of DBE reaching the bilioenteric anastomotic sites was 68.0% (17/25), and the success rate of IVR was 88.2% (15/17). There were three cases of Type I and 12 cases of Type II. Type II had a significantly longer cold ischemic time and higher recurrence rate than Type I (P = 0.005 and P = 0.006). In conclusion, DBE is a less invasive and safe treatment method that is capable of reaching the bilioenteric anastomotic site after pediatric LDLT and enables IVR to be performed on strictures, and its treatment outcomes are improving. Type II and long cold ischemic time are risk factors for intractable bilioenteric anastomotic stricture.

1 February 2018 in Anz Journal of Surgery
Verified
Journal Article
Closed access
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SUSatoko Umetsu
Satoko Umetsu
TWTaiichi Wakiya
Taiichi Wakiya
KIKeinosuke Ishido
Keinosuke Ishido
DKDaisuke Kudo
Daisuke Kudo
NKNorihisa Kimura
Norihisa Kimura
KHKenichi Hakamada
Kenichi Hakamada

20 August 2013 in Annals of Surgical Oncology
Verified
Journal Article
Closed access
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TWTaiichi Wakiya
Taiichi Wakiya
DKDaisuke Kudo
Daisuke Kudo
YTYoshikazu Toyoki
Yoshikazu Toyoki
KIKeinosuke Ishido
Keinosuke Ishido
NKNorihisa Kimura
Norihisa Kimura
KHKenichi Hakamada
Kenichi Hakamada

25 November 2014 in Liver Transplantation
Verified
Journal Article
Open access
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NYNaoya Yamada
Naoya Yamada
YSYukihiro Sanada
Yukihiro Sanada
YHYuta Hirata
Yuta Hirata
NONoriki Okada
Noriki Okada
TWTaiichi Wakiya
Taiichi Wakiya
KMKoichi Mizuta
Koichi Mizuta
In the field of pediatric living donor liver transplantation (LDLT), physicians sometimes must reduce the volume of left lateral segment (LLS) grafts to prevent large‐for‐size syndrome. There are 2 established methods for decreasing the size of an LLS graft: the use of a segment 2 (S2) monosegment graft and the use of a reduced LLS graft. However, no procedure for selecting the proper graft type has been established. In this study, we conducted a retrospective investigation of LDLT and examined the strategy of graft selection for patients weighing ≤6 kg. LDLT was conducted 225 times between May 2001 and December 2012, and 15 of the procedures were performed in patients weighing ≤6 kg. We selected S2 monosegment grafts and reduced LLS grafts if the preoperative computed tomography (CT)–volumetry value of the LLS graft was >5% and 4% to 5% of the graft/recipient weight ratio, respectively. We used LLS grafts in 7 recipients, S2 monosegment grafts in 4 recipients, reduced S2 monosegment grafts in 3 recipients, and a reduced LLS graft in 1 recipient. The reduction rate of S2 monosegment grafts for use as LLS grafts was 48.3%. The overall recipient and graft survival rates were both 93.3%, and 1 patient died of a brain hemorrhage. Major surgical complications included hepatic artery thrombosis in 2 recipients, bilioenteric anastomotic strictures in 2 recipients, and portal vein thrombosis in 1 recipient. In conclusion, our graft selection strategy based on preoperative CT‐volumetry is highly useful in patients weighing ≤6 kg. S2 monosegment grafts are effective and safe in very small infants particularly neonates.Liver Transpl 21:233‐238, 2015. © 2014 AASLD.