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Dive into the research topics where Takayuki Hamatsu is active.

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Featured researches published by Takayuki Hamatsu.


Annals of Surgery | 2001

Bile Leakage After Hepatic Resection

Yo Ichi Yamashita; Takayuki Hamatsu; Tatsuya Rikimaru; Shinji Tanaka; Ken Shirabe; Mitsuo Shimada; Keizo Sugimachi

ObjectiveTo identify the perioperative risk factors for postoperative bile leakage after hepatic resection, to evaluate the intraoperative bile leakage test as a preventive measure, and to propose a treatment strategy for postoperative bile leakage according to the outcome of these patients. Summary Background DataBile leakage remains a common cause of major complications after hepatic resection. MethodsBetween January 1985 and June 1999, 781 hepatic resections without bilioenteric anastomosis were performed at the authors’ institution. Perioperative risk factors related to postoperative bile leakage were identified using univariate and multivariate analysis. The characteristics of patients with intractable bile leakage and the effect of intraoperative bile leakage test were also examined. Management was evaluated in relation to the outcomes and the clinical characteristics of the patients with bile leakage. ResultsBile leakage developed in 31 (4.0%) of 781 hepatic resections. This complication carried high risks for surgical death (two patients [6.5%] died). The stepwise logistic regression analysis identified high-risk surgical procedure, in which the cut surface exposed the major Glisson’s sheath and included the hepatic hilum (i.e., anterior segmentectomy, central bisegmentectomy, or total caudate lobectomy), as the independent predictor of the development of postoperative bile leakage. None of the 102 cases in which an intraoperative bile leakage test was performed were subsequently complicated by postoperative bile leakage, and the preventive effect of the test was statistically significant. Patients with fisterographically demonstrable leakage from the hepatic hilum and with postoperative uncontrollable ascites had poor outcomes. ConclusionPatients with bile leakage from the hepatic hilum and postoperative uncontrollable ascites tend to have a poor prognosis. Therefore, especially when a high-risk surgical procedure is performed in patients with liver cirrhosis, more careful surgical procedures and use of an intraoperative bile leakage test are recommended.


Oncology | 2007

Clinical Significance of Histone Deacetylase 1 Expression in Patients with Hepatocellular Carcinoma

Tatsuya Rikimaru; Akinobu Taketomi; Yo-ichi Yamashita; Ken Shirabe; Takayuki Hamatsu; Mitsuo Shimada; Yoshihiko Maehara

Objective: Histone deacetylases (HDACs) play an important role in chromatin remodeling, gene repression and regulating cell cycle progression and differentiation. This study was designed to clarify the role of HDAC1 expression in hepatocellular carcinoma (HCC). Method: The expression of HDAC1 in 47 patients with surgically resected HCC was immunohistochemically examined and analyzed in relation to their clinicopathological factors. The patients were divided into two groups according to the expression status of HDAC1: a high HDAC1 group (n = 25) with more than 20% of positively stained cells and a low HDAC1 group (n = 22) with 20% or fewer positively stained cells. Results: A high HDAC1 expression indicated a higher incidence of cancer cell invasion into the portal vein, a poorer histological differentiation, and a more advanced TNM stage. The survival rates after a surgical resection in low and high HDAC1 patients at 1, 3, 5 and 10 years were 100, 95.5, 81.8 and 60.8% and 88.0, 60.0, 40.0 and 32.0%, respectively (p = 0.008). A multivariate analysis using the Cox regression analysis showed that a high HDAC1 expression was an independent prognostic factor of HCC in patients after hepatic resection (relative risk: 10.1, p = 0.0018). Conclusions: High HDAC1 expression might have an important role in the aggressiveness and cell dedifferentiation, and its expression status may be a useful biomarker for predicting the outcome of the patients with HCC.


American Journal of Surgery | 2001

The role of macroscopic classification in nodular-type hepatocellular carcinoma

Mitsuo Shimada; Tatsuya Rikimaru; Takayuki Hamatsu; Yo-ichi Yamashita; Takahiro Terashi; Kenichi Taguchi; Shinji Tanaka; Ken Shirabe; Keizo Sugimachi

BACKGROUND Little has been reported on the role of macroscopic classification of hepatocellular carcinoma (HCC). We hypothesized that macroscopic classification of HCC might have a strong correlation with long-term prognosis after hepatectomy. METHODS Four hundred and four patients with a macroscopically nodular type of HCC who underwent a hepatectomy were studied. The patients were divided into three groups: single nodular (SN) group (n = 312); single nodular with extranodular growth (SNEG) group (n = 52); and confluent multinodular (CMN) group (n = 40). Clinicopathological variables were compared among the three groups. The patient survival rate was also compared among the three groups. Finally, a multivariate analysis was performed to clarify the independent significant variables of the long-term prognosis. To confirm the consistency of the results in small-size HCC, the same analyses were made using patients whose tumor size was equal to or less than 3 cm in diameter. RESULTS The alpha-fetoprotein value, tumor size, and rate of absolute noncurative operation in the SNEG group were higher than in other groups. The positive rate of both portal vein invasion of cancer cells and intrahepatic metastasis in the SN group was lower than those in other groups. The rate of poorly differentiated histology in the SN group was lower than in the other groups. Patient survival in the SNEG group was worst among the three groups. However, patient survival showed no significant difference between the SN and CMN groups. The multivariate analysis showed that the presence of intrahepatic metastasis, the macroscopic classification of SNEG type, and absolute noncurative operation were independent poor prognostic indicators. The results for patients with small HCCs measuring equal to or less than 3 cm in diameter were quite similar to the results for the other patients. CONCLUSIONS Among the three subtypes of macroscopically nodular type of HCCs, the SNEG type showed higher rates of portal vein invasion of cancer cells, intrahepatic metastasis, and poorly differentiated histology. The patient survival rate in the SNEG type was worst, and the SNEG type was an independent poor prognostic indicator. The macroscopic classification of HCC, especially the SNEG type, helps predict the long-term outcome after hepatectomy.


World Journal of Surgery | 2001

Characteristics of Multicentric Hepatocellular Carcinomas: Comparison with Intrahepatic Metastasis

Mitsuo Shimada; Takayuki Hamatsu; Yo-ich Yamashita; Tatsuya Rikimaru; Kenichi Taguchi; Tohru Utsunomiya; Ken Shirabe; Keizo Sugimachi

Characteristics of multicentric hepatocellular carcinomas (HCCs) remain obscure. We therefore aimed to clarify them and compare them with HCC with intrahepatic metastases. A series of 118 patients who had definite hepatitis C viral status and multinodular HCC were divided into two groups: a multicentric occurrence (MO) group (n= 38), with multicentric HCCs; and an intrahepatic metastasis (IM) group (n= 80), with HCC having intrahepatic metastases. Clinicopathologic variables, including the patients survival and disease-free survival rates, were compared between the MO and IM groups. Univariate analysis revealed the presence of esophageal varices, the presence of hepatitis C virus infection, a platelet count of less than 10 × 104/μl, hepaplastin test, γ-globulin, the histologically active hepatitis, tumor size, des-γ-carboxy prothrombin > 0.1 AU/ml, positive portal vein invasion, and histologic grade as discriminating factors. The MO score to differentiate multicentric HCCs from intrahepatic metastatic HCCs was determined using the following four independent factors selected by a stepwise regression analysis: the presence of hepatitis C virus infection, a platelet count of less than 10 × 104/μl, tumor size, and histologic grade. The sensitivity and specificity of the MO scores using those factors were 84% and 70%, respectively, when the cutoff value was 0.4. The disease-free survival rate in the MO group was similar to that in the IM group, whereas the survival rate in the MO group was significantly better than that in the IM group. The multivariate analysis revealed the multicentric occurrence of HCC as one of the independent prognostic factors. Clinicopathologic factors differentiating multicentric HCCs from intrahepatic metastatic HCCs were the presence of hepatitis C virus infection, a platelet count of less than 10 × 104/μl, small tumor size, and low histologic grade.


Journal of The American College of Surgeons | 2000

The importance of hepatic resection for hepatocellular carcinoma originating from nonfibrotic liver

Mitsuo Shimada; Tatsuya Rikimaru; Keishi Sugimachi; Takayuki Hamatsu; Yo-ichi Yamashita; Shinichi Aishima; Kenichi Taguchi; Shinji Tanaka; Ken Shirabe; Keizo Sugimachi

BACKGROUND Our study aimed to clarify the characteristics of hepatocellular carcinoma (HCC) in patients with a nonfibrotic liver and the role of surgical resection for HCC in nonfibrotic liver compared with patients with HCC in fibrotic or cirrhotic livers. STUDY DESIGN A total of 516 patients who underwent hepatectomy between April 1985 and June 1999 were classified into two groups: a nonfibrotic liver group (n=65) and a fibrotic liver group (n=451), which included fibrotic or cirrhotic livers. Clinicopathologic variables were then compared between the groups, including disease-free survival rate and patient survival rate. RESULTS Only 8 of 65 patients (12.3%) with a nonfibrotic liver showed a histologically completely normal liver. The numbers of men and patients with alcohol abuse in the nonfibrotic liver group were higher than in the fibrotic liver group. The numbers of patients with positive hepatitis B antigen and positive hepatitis C antibody in the nonfibrotic liver group were lower than in the fibrotic liver group. Results of liver function tests in the nonfibrotic liver group were better than those in the fibrotic liver group. The rates of both portal vein and hepatic vein invasion of cancer cells in the nonfibrotic liver group were higher than in the fibrotic liver group. The tumor size in the nonfibrotic liver group was larger than in the fibrotic liver group. The patient survival and disease-free survival rates in the nonfibrotic liver group were better than in the fibrotic liver group. CONCLUSIONS Hepatic resection can be beneficial for patients with HCC originating from a nonfibrotic liver when compared with fibrotic or cirrhotic patients with HCC.


Journal of The American College of Surgeons | 2000

Clinicopathologic features and postoperative prognosis of multicentric small hepatocellular carcinoma.

Tohru Utsunomiya; Mitsuo Shimada; Kenichi Taguchi; Hirofumi Hasegawa; Yo-ichi Yamashita; Takayuki Hamatsu; Shinichi Aishima; Keizo Sugimachi

BACKGROUND Assessment of clinicopathologic characteristics and postoperative prognoses for patients with multicentric hepatocellular carcinoma (HCC) is important to determine not only a need to operate, but also an appropriate treatment after hepatic resection. STUDY DESIGN Between May 1990 and April 1998, among 116 patients with an initial hepatectomy for HCC measuring 3 cm or less in maximum diameter, 34 patients had multicentric HCC (MC group), and 82 patients had single nodular HCC (SN group). To clarify the clinicopathologic features of patients in the MC group versus the SN group, we compared both the clinicopathologic parameters and the postoperative prognosis after curative hepatectomy between the two groups. RESULTS The percentages of patients positive for hepatitis B surface antigen and hepatitis C virus antibody were not significantly different between the two groups. No differences were noted in pathologic characteristics of the main tumor or tumor markers. On the other hand, in the MC group, the percentage of patients evaluated in a Childs classification as either B or C was significantly higher (p < 0.05) than that of patients in the SN group, indicating that patients with multicentric HCC have a poor hepatic functional reserve. Both survival and disease-free survival of patients in the MC group who underwent a curative hepatectomy did not differ statistically from those in the SN group. CONCLUSIONS Our results indicate that hepatic resection is useful, even for patients with multicentric HCC, if a curative hepatectomy can be performed and liver function can be saved, despite their poor hepatic functional reserve.


Cancer Letters | 2000

The role of des-γ-carboxy prothrombin levels in hepatocellular carcinoma and liver tissues

Mitsuo Shimada; Yo-ichi Yamashita; Takayuki Hamatsu; Hirofumi Hasegawa; Tohru Utsunomiya; Shinichi Aishima; Keizo Sugimachi

We aimed to clarify the clinical significance of des-γ-carboxy prothrombin (DCP) levels in both hepatocellular carcinoma (HCC) and liver tissues with a special reference to the relationship between DCP level in non-cancerous parts of the liver and the multicentric occurrence of HCC. Twenty-eight patients with HCC, who underwent hepatectomy, were studied. Surgical specimens were obtained from both HCC and non-cancerous liver of each patient. After the preparation of the liver tissues, including tissues with HCC, the DCP levels both in HCC and non-cancerous liver tissue were measured using an electro-chemiluminescence immunoassay. The correlation was investigated between DCP levels and other clinicopathological factors. The DCP level of HCC ranged from 55 to 77 735 U/0.1 g tissue weight, with a median of 2801, while the DCP level of non-cancerous parts of the liver ranged from 24 to 721 U/0.1 g tissue weight, with a median of 86. The DCP level in the liver tissue in patients having a multicentric occurrence of HCC was significantly higher than that in patients without multicentric occurrence of HCC. The logarithm of the plasma DCP level correlated with that of the DCP level in HCC (correlation coefficient =0.46; P<0.05). No significant correlation was found between the DCP level in HCC and other clinicopathological parameters. The DCP level in non-cancerous parts of the liver with simultaneous multicentric occurrence of HCC was significantly higher than that in the liver without multicentric HCC. Furthermore, the DCP level in non-cancerous parts of the liver was one of the most important predictable factors of the multicentric occurrence of HCCs among various clinicopathological factors. Therefore, the DCP level may have an important role in hepatocarcinogenesis.


Cancer Letters | 2000

The significance of thymidine phosphorylase activity in hepatocellular carcinoma and chronic diseased livers: a special reference to liver fibrosis and multicentric tumor occurrence

Mitsuo Shimada; Hirofumi Hasegawa; Tatsuya Rikimaru; Tomonobu Gion; Takayuki Hamatsu; Yo Ichi Yanashita; Ken Shirabe; Keizo Sugimachi

The role of thymidine phosphorylase (TP), an angiogenic factor, in hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to clarify the significance of TP in HCC. Thirty-seven patients with HCC, who underwent hepatectomy, were included. The TP activity in both cancerous and non-cancerous parts of livers were measured by an enzyme-linked immunosorbent assay. Another 11 patients without HCC were used to evaluate the TP activity in the non-cancerous parts of livers. Both the cancerous and non-cancerous TP activities were clinico-pathologically investigated with special reference to the multicentric occurrence of HCCs and the degree of liver fibrosis; consisting of normal, fibrosis and cirrhosis. The TP activity in the cancerous part was 94.6 +/- 70.2 U/mg protein, while that in non-cancerous parts of the liver was 80.9 +/- 48.8 U/mg protein. No significant difference was observed. The TP activity in the cancerous part did not correlate with any clinicopathological variables, such as tumor differentiation, portal vein invasion, intrahepatic metastases and prognosis. However, the TP activity in the non-cancerous parts of the liver correlated with the degree of fibrosis (normal/fibrosis/cirrhosis = 34:74:90 U/ mg protein, respectively). Furthermore, regarding the correlation between TP activity in the non-cancerous parts and the simultaneously multicentric occurrence of HCC, the TP activity in the multicentric group (n = 8; 121 U/mg protein) was significantly higher than that in the non-multicentric group (n = 29; 70 U/mg protein). The TP activity in the non-cancerous parts increased in proportion to the degree of liver fibrosis. Furthermore, it is suggested that the higher TP activity in the non-cancerous part is related to the multicentric occurrence of HCCs.


The Annals of Thoracic Surgery | 2014

An Idiopathic Azygos Vein Aneurysm Mimicking a Mediastinal Mass

Yoshinobu Ichiki; Takayuki Hamatsu; Taketoshi Suehiro; Makiko Koike; Fumihiro Tanaka; Keizo Sugimachi

Azygos vein aneurysms are very rare causes of mediastinal masses and are usually accidental findings on chest roentgenography. Most are detected in patients with portal hypertension or venous malformations. An idiopathic azygos vein aneurysm is assumed to be congenital and is much more exceptional. We present the case of a 76-year-old man who underwent excision of an idiopathic azygos vein aneurysm by video-assisted thoracoscopic surgery (VATS).


International Journal of Surgery Case Reports | 2015

Surgical management of pulmonary arteriovenous fistula in a female patient

Yoshinobu Ichiki; Junji Kawasaki; Takayuki Hamatsu; Taketoshi Suehiro; Makiko Koike; Fumihiro Tanaka; Keizo Sugimachi

Introduction We herein describe a rare case of a pulmonary arteriovenous fistula (PAVF). Presentation of case The patient was a 20-year-old asymptomatic female, admitted to our hospital because of an abnormal shadow in the right lung field on chest X-rays. Chest computed tomography (CT) revealed two nodules with well-defined margins in the right upper and lower lobes. Contrast-enhanced three-dimensional CT (3D-CT) revealed two enhanced solitary lung nodules which were connected with linear structures suggestive of feeding arteries and drainage veins, respectively. Based on these findings, we made a preoperative diagnosis of PAVF. We performed partial pulmonary resection of the right upper and lower lobes by video-assisted thoracoscopic surgery (VATS). The histopathological findings revealed small and medium-sized vascular channels composed of arteries with mild and irregularly thickened muscle walls and juxtaposed or seemingly anastomosing dilated veins. Based on these findings, a diagnosis of PAVF was confirmed. The patient had an uneventful postoperative course. Discussion A PAVF is often associated with various complications, and pregnancy could be a risk factor for these complications because of the increase in the shunt fraction. Females with known PAVF should be maximally treated prior to becoming pregnant as complications of PAVF during pregnancy can have devastating consequences. Therefore, we thought that treatment should be recommended in this case in the event she might later choose to become pregnant. Conclusion Surgical resection using VATS for a limited number of ipsilateral isolated pulmonary arteriovenous fistulae is recommended due to its safety, low recurrence and low mortality rate.

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Fumihiro Tanaka

University of Occupational and Environmental Health Japan

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Yoshinobu Ichiki

University of Occupational and Environmental Health Japan

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Shinji Tanaka

Tokyo Medical and Dental University

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