Yasunori Sohara

Jichi Medical University, Totigi, Tochigi, Japan

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Publications (144)256.32 Total impact

  • Isao Okazaki · Shigemi Ishikawa · Yasunori Sohara ·
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    ABSTRACT: Global statistics estimate that 15% of all cases of lung cancer in men and 53% in women are not attributable to smoking, and these data indicate that worldwide, approximately 25% of patients with lung cancer are never smokers. The etiology of lung cancer is disputed. The present study reviews the genes associated with susceptibility to lung cancer among never smokers and suggests possibilities for the involvement of metabolic syndrome. The environment appears to have changed the genes susceptible to lung cancer. Classical genes associated with lung cancer are decreasing and novel emerging genes may reflect changes in lifestyle. We provide evidence that the genes associated with susceptibility to lung cancer in never smokers are very similar to those reported in patients with metabolic syndrome, and that simply quitting smoking is not sufficient as the primary means of preventing lung cancer.
    Anticancer research 10/2014; 34(10):5229-5240. · 1.83 Impact Factor
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    ABSTRACT: Backgroun: Thymic cancer is an uncommon neoplasm. In particular, thymic basaloid carcinoma is extremely rare. Case: A 71-year-old male with a history of surgery for primary lung cancer and rectal cancer exhibited an elevated serum level of carcinoembryonic antigen (CEA) with an anterior mediastinal cyst and tumor on a computed tomography scan. Fluorodeoxyglucose-positron emission tomography showed a high standardized uptake value (SUV) max value of 8.4 at the mediastinal tumor site with no additional uptake throughout the body. The patient underwent tumor resection via median sternotomy. The histopathological findings revealed a thymic basaloid carcinoma (pT2N0M0, stage II and Masaoka stage II). Adjuvant radiation therapy was administered, and the patient's CEA level normalized. Unfortunately, multiple bone metastases, right adrenal metastasis and an elevated serum CEA level developed 13 months after resection. The patient is currently undergoing palliative radiotherapy for the bone lesions. Conclusions: We herein reported a rare case of thymic basaloid carcinoma that developed after lung and rectal cancer resection. Solitary lesions with a cystic component in the mediastinum should therefore be accurately diagnosed and resected, even after resection of a prior malignancy.
    Haigan 01/2013; 53(6):751-754. DOI:10.2482/haigan.53.751
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    ABSTRACT: In 1986, Japanese Association for Thoracic Surgery started a nationwide survey of the number of primary lung cancer undergoing resection and this survey was continued annually. Thereafter, investigations of lung cancer surgical results have been conducted three times. The postoperative overall 5-year survival rate was 47.8% in resected cases in 1989, 52.3% in 1994, and 62.0% in 1999, showing improvement over the decade (p < 0.01). To clarify the factors influencing survival improvements retrospectively. The subjects of the investigation are the patients who underwent resection for primary lung cancers in 1989, 1994, and 1999. Postoperatively, after 5 years, surveys of surgical results were sent to institutes where lung cancer resection had been performed. The subjects undergoing resection who provided 10 items (age, sex, pathologic T factor, pathologic N factor, pathologic M factor, date of resection, histology, curability, prognosis, and survival time) numbered 3004 in 1989, 6895 in 1994, and 12,235 in 1999. They were classified according to the Union International Contre le Cancer 1997 revised tumor, node, and metastasis classification. Differences in age, gender, histology, pathologic stage, curability, and operative death rates were analyzed for each survey year. According to the changes in proportions, the cases over 70 years of age, women, and pathologic stage I increased significantly (p < 0.001), whereas in cases with small cell lung cancer, incomplete resection and operative death decreased significantly over time (p < 0.001). The postoperative 5-year survival rate in Japan improved between 1989 and 1999. The main cause of this improvement was the increase in early stage lung cancer, especially cases with tumors 2 cm or less in size.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 11/2009; 4(11):1364-9. DOI:10.1097/JTO.0b013e3181ba2054 · 5.28 Impact Factor
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    ABSTRACT: Biopsy by video-assisted thoracoscopic surgery (VATS) for interstitial pneumonia allows collection of samples sufficient for accurate histologic diagnosis. Although VATS is relatively safe, several reports have suggested that surgical lung biopsy may be a risk factor for acute exacerbation of idiopathic pulmonary fibrosis (IPF). We retrospectively reviewed data on the 113 cases that underwent biopsy by VATS to diagnose diffuse parenchymal lung disease in our department between 1994 and 2006, and analyzed its complications, in particular, risk of acute exacerbation of IPF. As the final diagnosis, idiopathic interstitial pneumonia was most frequent, involving 52 cases, of which IPF was most frequently found followed by nonspecific interstitial pneumonia and cryptogenic organizing pneumonia, in that order. Among our cases, there were 2 deaths after VATS (mortality rate, 1.8%), and both were IPF cases with acute exacerbation. When examining clinical markers in the 2 fatal IPF cases with acute exacerbation, we found that the percentage of predicted forced vital capacity was 55 or lower, percentage of predicted carbon monoxide diffusing capacity was 40 or lower, serum interstitial pneumonia markers KL-6 and SP-D were elevated, intraoperative inhalation of 100% O2 was 80 minutes or longer, and postoperative thoracic drainage was required for 10 days or longer. Although acute exacerbations of IPF seem to occur at any time during the course of disease, it is important to be aware of the possibility of acute exacerbation of IPF after VATS.
    Journal of Bronchology and Interventional Pulmonology 10/2009; 16(4):229-35. DOI:10.1097/LBR.0b013e3181b767cc
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    ABSTRACT: This retrospective study was designed to identify the predictors of long-term survival and the risk factors for complications after surgery in patients aged 80 years or older with clinical (c)-stage I non-small cell lung cancer. The Japanese Joint Committee of Lung Cancer Registry collated the clinicopathological profiles and outcomes of 13,344 patients who underwent pulmonary resection for primary lung cancer in 1999. The data of 367 patients aged 80 years or older with c-stage I non-small cell lung cancer were analyzed for prognostic factors and risk factors for postoperative complications. The median age was 82 years (range, 80-90 years). Of the total patient number, 102 (27.8%) had some form of comorbidity diagnosed preoperatively. Thirty-one (8.4%) patients presented with postoperative complications, and the operative mortality was 1.4%. The 5-year survival rates were 55.7% for c-stage I patients, 62.0% for c-stage IA, and 47.2% for c-stage IB. Advanced pathologic stage and comorbidity were significant independent predictors of shortened survival (p < 0.0001 and p = 0.032, respectively). Comorbidity and mediastinal lymph node dissection were identified as factors that increased the risk of postoperative complications (p < 0.0001 and p = 0.036, respectively). Survival rates were independent of the extent of pulmonary resection (lobectomy or limited resection). Octogenarian patients with c-stage I lung cancer in this study had a satisfactory long-term outcome and low-mortality rate. Comorbidity is a factor associated with both prognosis and operative risks. A selection of the patients who would be curable without mediastinal lymph node dissection after an accurate preoperative staging is beneficial to decrease the postoperative complications because this procedure is a risk factor.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 07/2009; 4(10):1247-53. DOI:10.1097/JTO.0b013e3181ae285d · 5.28 Impact Factor
  • T Ishizuka · S Endo · H Tsubochi · T Nakano · C Miwa · K Watanabe · S Koyama · M Nokubi · Y Sohara ·
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    ABSTRACT: An 83-year-old woman was referred to our hospital to examine for an infiltration shadow in the right lower lobe with progressive bronchorea Computed tomography showed an infiltration lesion with the longest diameter of 10 cm in the right lower lobe and a tumor with the longest diameter of 3 cm in the middle lobe. Serum level of carbohydrate antigen (CA) 19-9 markedly increased to 37,670 U/ml over a period of 3 months. The pathologic study obtained by a transbronchial tumor biopsy revealed a mucinous adenocarcinoma The patient underwent video-assisted thoracoscopic right middle and lower bi-lobectomies with nodal sampling. Postoperative course was uneventful Pathologic study revealed an adenocarcinoma with mixed subtypes, predominantly composed of mucinous bronchiolo-alveolar cell carcinoma (BAC). Immunohistochemical study showed CA19-9 positivity in the apical surface of some tumor cells and diffuse patterns of other tumor cells. Postoperative course was uneventful and serum CA19-9 levels decreased within the normal range. Clinico-pathologic features of the lung cancer patients with serum elevation of CA19-9 and CA19-9 positivity in the cancer cells was discussed. CA19-9 can be an useful tumor marker in the selected patients with mucinous BAC.
    Kyobu geka. The Japanese journal of thoracic surgery 07/2009; 62(6):509-12.
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    ABSTRACT: No analyses have been reported on the impact of visceral pleura invasion (VPI) on staging, in relation with the International Association for the Study of Lung Cancer proposals for the 7th edition of the tumor, node, metastasis (TNM) classification of the International Union Against Cancer staging system. The purpose of this study was to evaluate the impact of VPI on survival and propose a method of incorporating VPI status into the TNM classification. We reviewed the data on 9758 non-small cell lung cancer patients, who underwent anatomic surgical resection in 1999, accumulated by the Japanese Joint Committee for Lung Cancer Registration, to gain insight into their clinicopathologic characteristics and outcomes. VPI was defined as tumor extension beyond the elastic layer of the visceral pleura. Patients were divided into nine groups according to VPI status and tumor diameter, in accordance with the International Association for the Study of Lung Cancer proposals. On the basis of survival, the nine groups were divided into the following five levels: tumors < or =2 cm without VPI; tumors < or =2 cm with VPI and tumors 2.1 to 3 cm without VPI; tumors 2.1 to 3 cm with VPI and tumors 3.1 to 5 cm without VPI; tumors 3.1 to 5 cm with VPI and tumors 5.1 to 7 cm without VPI; and tumors 5.1 to 7 cm with VPI and tumors >7 cm without VPI or T3 tumors. The T status of tumors, 7 cm or less, with VPI should be upgraded to the next T level in the future edition of the TNM classification of International Union Against Cancer staging system.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 06/2009; 4(8):959-63. DOI:10.1097/JTO.0b013e3181a85d5e · 5.28 Impact Factor
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    ABSTRACT: Video-assisted thoracoscopic resection for mediastinal mature teratoma is sometimes converted to open thoracotomy. Because it has rich components including pancreatic tissue and dense adhesion, even when it is asymptomatic. Prior to thoracoscopic resection, extraction of the cystic components with the aid of a 20 Fr tube can provide a wide thoracoscopic view leading to easier complete removal. Between October 1998 and June 2008, 6 patients (1 man and 5 women) with benign mediastinal mature teratoma underwent the thoracoscopic operations. The average age was 36.3 (range, 24-54). The mean diameter was 9.0 cm (range, 5-11 cm). The mean operation time was 143 minutes and the mean blood loss was 103 ml. Neither complications nor tumor recurrences developed during the mean follow-up period of 3.4 years. The presented thoracoscopic surgery for benign mature teratoma is a feasible procedure.
    Kyobu geka. The Japanese journal of thoracic surgery 06/2009; 62(5):358-61.
  • Hiroyoshi Tsubochi · Y Kanai · T Nakano · S Koyama · Y Sohara · S Endo ·
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    ABSTRACT: We reviewed the data on 171 patients who underwent thoracoscopic lobectomy for lung cancer via 5 access ports at our institution between April 2005 and May 2008. Port-access lobectomy was completed in 153 patients and conversions to open thoracotomy were required in 18 patients. Among the above 153 patients, mean operative time was 145 minutes and the mean blood loss was 159 ml. Morbidity rate was 12% and mortality rate was 0.7%. Pathologic study demonstrated stage I in 106 patients (69%), stage II in 16 patients (11%), and stage III in 31 patients (20%). At mean follow-up of 635 days after surgery, the overall 3-year survival rates of the patients with non-small cell lung cancer at stage I, stage II, and stage III were 88%, 80%, and 79%, respectively. Port-access lobectomy with mediastinal lymph nodes dissection for lung cancer is feasible with low morbidity and mortality rates. Long-term outcomes should be reviewed in the near feature.
    Kyobu geka. The Japanese journal of thoracic surgery 05/2009; 62(4):267-70.
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    Shunsuke Endo · Hiroyoshi Tsubochi · Tomoyuki Nakano · Yasunori Sohara ·
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    ABSTRACT: Anatomical variations of the pulmonary vessels present a potential risk of intraoperative bleeding and damage to pulmonary circulation during pulmonary resection. We present details of a dangerous variation of the superior pulmonary vein associated with thoracoscopic right lower lobectomy that could potentially be divided if there was no preoperative foreknowledge of individual vessel configurations.
    The Annals of thoracic surgery 03/2009; 87(2):e9-e10. DOI:10.1016/j.athoracsur.2008.08.051 · 3.85 Impact Factor
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    ABSTRACT: We herein report a case of large cell neuroendocrine carcinoma (LCNEC) originating in the right lung upper lobe and showing unique features at relapse in the right middle lobe. The relapsed tumor pathology included a carcinoembryonic antigen (CEA)-positive mantle component and a CEA-negative core area. The latter showed the same pathological picture as the original tumor, both histologically and immunohistochemically. The serum CEA concentration did not increase until the tumor relapsed, and it fell to within the normal range after resection of the relapsed tumor. Rarely, a newly elevated tumor marker suggests relapse, even in resected cases with a negative immunohistochemical study for the marker.
    General Thoracic and Cardiovascular Surgery 12/2008; 56(11):547-50. DOI:10.1007/s11748-008-0297-9
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    ABSTRACT: We retrospectively evaluated the surgical outcome after sleeve lobectomy and pneumonectomy with tracheobronchial reconstruction for lung cancer. From 1993 to 2008, 46 patients with primary lung cancer underwent these surgical procedures. Seventeen patients (37%) received induction therapy, 15 received chemotherapy, while chemoradiotherapy or radiotherapy alone were received by one patient each. Sleeve lobectomy without carinal resection was performed in 41 patients. Carinal resection with 2 sleeve pneumonectomies was performed in 5 patients. There were no operative deaths. Bronchopleural fistula occurred in one patient, who required completion pneumonectomy. One patient presented local mucosal necrosis in the anastomotic site and was managed conservatively. Two patients had bronchial strictures as late complications and successfully dilated by a balloon using bronchoscopy. Overall 5-year and 10-year survival rates were 54% and 48%, respectively. No recurrence developed at any anastomotic site. The results showed that sleeve lobectomy and pneumonectomy with tracheobronchial reconstruction can be performed with low mortality and bronchial anastomotic complication rates. As well, local control of the tumor was satisfactory.
    Kyobu geka. The Japanese journal of thoracic surgery 11/2008; 61(11):934-8.
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    ABSTRACT: In nonrandomized studies, the video-assisted thoracic surgical (VATS) lobectomy seems to be a safe and effective procedure for treatment of lung cancer. However, there are some difficulties in VATS complete mediastinal lymph node dissection. The presence of the lymph node deep in the mediastinal space necessitates retraction of the surrounding organs. Therefore, we developed a retractor to create enough working space during the VATS procedure. To dissect lymph nodes, we use endoscopic bipolar forceps. These instruments are connected to a special electrosurgical generator to apply bipolar soft coagulation, which enables simultaneous dissection and sealing. Thus, "en bloc" lymph node dissection can be performed during the VATS procedure.
    The Annals of thoracic surgery 10/2008; 86(3):1036-7. DOI:10.1016/j.athoracsur.2008.04.002 · 3.85 Impact Factor
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    ABSTRACT: We herein report a 38-year-old man who had spontaneous regression of a thymoma with repeating episodes of chest pain that initially occurred 2 years earlier when the tumor was 35 mm in the long axis. Left video-assisted thoracoscopic thymothymectomy was performed. Pathology examination showed a thymoma 15 mm in the long axis, classified B2 in the World Health Organization classification and stage II by Masaoka staging. The feeding arteriole of the tumor, occluded by organized thrombi, was suggested to be the cause of coagulation necrosis. The patient recovered well from surgery without complication and with no episodes of chest pain at the 9-month outpatient follow-up.
    General Thoracic and Cardiovascular Surgery 10/2008; 56(9):468-71. DOI:10.1007/s11748-008-0277-0
  • T Endo · T Hasegawa · Y Tezuka · Y Kanai · S Otani · S Yamamoto · K Tetsuka · Y Sato · S Endo · Y Sohara ·
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    ABSTRACT: We report a rare case of atypical pulmonary carcinoid tumor accompanied by elevation of serum gastrin-releasing peptide precursor (ProGRP). A 55-year-old male presented to our hospital with a history of bloody sputum. The level of serum ProGRP was elevated to 781 pg/ml (normal < 46 pg/ml). Chest computed tomography (CT) revealed a solitary pulmonary tumor in the left lower lobe with sub-carinal lymph node enlargement. Transbronchial lung biopsy showed a pulmonary carcinoid, therefore left lower lobectomy with mediastinal lymph node dissection was performed. ProGRP decreased to normal level 1 month after operation. Histopathological diagnosis showed an atypical pulmonary carcinoid tumor.
    Kyobu geka. The Japanese journal of thoracic surgery 10/2008; 61(11):993-5.
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    Yasunori Sohara ·
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    ABSTRACT: When a rapidly reexpanding lung has been in a state of collapse for more than several days, pulmonary edema sometimes occurs in it. This is called reexpansion pulmonary edema (RPE). In this article, I present my views on the history, clinical features, morphophysiological features, pathogenesis, and treatment of RPE. Histological abnormalities of the pulmonary microvessels in a chronically collapsed lung will cause RPE, as well as mechanical stress exerted during reexpansion. Although the most effective treatment method is to treat the histological abnormalities of the pulmonary microvessels formed in a chronically collapsed lung, the cause of these abnormalities is not clear, making it difficult to put forward a precise treatment method. However, reasonably good effects can be expected from a symptomatic therapy that reduces the level of mechanical stress during reexpansion. In the future, it is expected that the cause of histological changes of the pulmonary microvessels in a chronically collapsed lung will be revealed, and appropriate therapies will therefore be developed according to this cause.
    Annals of thoracic and cardiovascular surgery: official journal of the Association of Thoracic and Cardiovascular Surgeons of Asia 09/2008; 14(4):205-9. · 0.72 Impact Factor
  • H Tsubochi · S Endo · T Nakano · Y Sohara ·
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    ABSTRACT: We herein report a procedure for thoracoscopic lobectomy with mediastinal dissection for primary lung cancer using 5 access ports. A thoracoscope is inserted through an access port on the mid-axillary line in the 6th intercostal space. The availability of 4 instruments through 4 ports makes it easy to divide bronchus and pulmonary vessels and to dissect mediastinal lymph nodes. Between April 2005 and March 2007, 88 patients with clinical stage I/II primary lung cancer underwent this thoracoscopic procedure. Mean (+/- SD) operation time was 148 +/- 42 minutes and mean (+/- SD) blood loss was 166 +/- 148 ml. No local recurrence was found in patients with pathologic stage I/II diseases, whereas ipsilateral mediastinal lymphadenopathy occurred in 2 with pathologic stage III A disease during the mean post-opetrative period of 518 +/- 200 days. The thoracoscopic surgery for lung cancer presented here was seen to be a feasible procedure and has the advantage of reducing operative time.
    Kyobu geka. The Japanese journal of thoracic surgery 08/2008; 61(7):557-60.
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    ABSTRACT: A 44-year-old woman who had undergone hystero-oophorectomy for uterine sarcoma presented to our hospital with palindromic pneumothorax and her chest CT revealed multiple cystic lesions. After admission video-assisted thoracoscopic surgery (VATS) showed the pulmonary lesions to be primarily leiomyoma, however, further examination revealed that her uterine sarcoma resected in 2000 exhibited not only mitosis but also venous invasion. We therefore considered her lung tumors as metastases from uterine leiomyosarcoma. Cases of secondary spontaneous pneumothorax (SSP) due to pulmonary metastases are rare and almost half are from mesenchymal tumors. Thin-wall cavities and cysts are formed by a check-valve mechanism in the process of pulmonary metastases formation. When multiple thin-wall cavities and cysts are found in the lung, pulmonary metastases should be considered as one of the causes, and pathological specimens obtained in past illness should be re-examined in detail.
    06/2008; 46(5):379-84.
  • Shunsuke Endo · H Tsubochi · S Matsuzawa · D Hori · T Nakano · Y Sohara ·
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    ABSTRACT: Patients with advanced non-small cell lung cancer invading a chest wall are surgical candidates if complete resection is possible. When a primary tumor locating the lower lobe invades an inferior chest wall, either a wide skin incision or double skin incisions to secure surgical views both for dissection of hilum and mediastinum and for inferior chest wall resection is necessary. Wider incision causes higher rate of wound necrosis and infection. We describe a combined approach of thoracoscopic and open chest surgery for lobectomy and inferior chest wall resection, respectively. Patient was a 68-year-old man with an advanced non-small cell lung cancer. Video-assisted thoracoscopic middle and lower lobectomies and mediastinal nodal dissection was completed via 5 ports. Chest wall resection including the posterior portion of the 9th and 10th ribs and the transverse process followed inferior postero-lateral thoracotomy. Postoperative course was uneventful. The present surgical approach can avoid a wide thoracotomy for an advanced lung cancer invading an inferior chest wall.
    Kyobu geka. The Japanese journal of thoracic surgery 06/2008; 61(5):375-8.
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    ABSTRACT: A 63-year-old man who had underwent video-assisted thoracoscopic bullectomy for left spontaneous pneumothorax 1 year before developed recurrent hemoptysis. Chest computed tomography showed previous stapling of the subsegmental bronchus in the left apico-posterior segment Bronchial arteriography showed hypervascularization of bronchial artery in the left upper segment and pooling of contrast medium along the staple-suture line. Video-assisted thoracoscopic apico-posterior segmentectomy was performed successfully. Pathological examination revieled hemosiderin lining along the surgical stump of B(1+2)cii, neither with infection nor infarction. These findings suggest that mechanical stapling of B(1+2)cii induced ischemia in the peripheral lung parenchyma causing bronchial hypervascularization. Late onset hemoptysis should be kept in mind as a complication after bullectomy with a mechanical stapler.
    Kyobu geka. The Japanese journal of thoracic surgery 05/2008; 61(4):340-3.

Publication Stats

3k Citations
256.32 Total Impact Points


  • 1992-2009
    • Jichi Medical University
      • • Division of General Surgery
      • • Department of Surgery
      • • Department of Pathology
      • • Division of Cardiovascular Surgery
      Totigi, Tochigi, Japan
  • 2008
    • Saitama Medical University
      Saitama, Saitama, Japan
  • 2006
    • Aomori Prefectural Central Hospital
      Aomori, Aomori, Japan
  • 1989
    • University of Tsukuba
      • Institute of Clinical Medicine
      Tsukuba, Ibaraki, Japan
  • 1987
    • McGill University
      Montréal, Quebec, Canada