Yoji Iwasaki
University of Tsukuba
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Featured researches published by Yoji Iwasaki.
Cancer | 1980
Takeshi Todoroki; Yoji Iwasaki; Takao Okamura; Kazuo Nagoshi; Hideo Asakura; Masayuki Nakano; Tetsuo Inada; Hiroshi Tsunemoto; Yoichiro Umegaki; Akira Nishimura; Masao Nakano; Hiroshi Sato
Since November 1973, intraoperative radiotherapy has been performed on five patients with unresectable, advanced carcinoma of the bile duct at the hepatic hilus and six patients with unresectable carcinoma of the gallbladder. A treatment cone with a diameter ranging from 4–10 cm was directly applied at the lesion. A single dose of 2500–3000 rad with 11 to 20 meV electrons was delivered. In all patients, recanalization of the obstructed bile duct was observed by the postoperative cholangiography. The local efficacy was confirmed histopathologically in eight autopsied materials and a specimen resected 105 days after radiotherapy. Mean survival time of patients with unresectable tumors was 10.9 ± 5.6 (SD) months after this radiotherapy. Intraoperative radiotherapy increased the effectiveness and length of palliation for the unresectable lesion.
Cancer | 1984
Akira Nishimura; Masao Nakano; Hiroshi Otsu; Kikuo Nakano; Koyo Iida; Suoh Sakata; Keiichi Iwabuchi; Koshi Maruyama; Michio Kihara; Takao Okamura; Takeshi Todoroki; Yoji Iwasaki
A detailed retrospective analysis of the efficacy of intraoperative radiotherapy (IOR) in advanced carcinoma of the pancreas is presented. During a 10‐year period from 1973 through 1982, 70 patients with advanced carcinoma of the pancreas were treated by multimodal methods, separate or combined therapy of surgery, IOR, and chemotherapy in two different institutions. Among these, 33 patients underwent IOR, mostly combined with additive surgery. A single dose of 20.1 to 40.0 Gy with 8 to 25 meV electrons was delivered through radiation cones ranging from 6 to 10 cm in diameter. Excellent relief was noticed in 50% of the patients who had complained of pain. Among Stage IV patients, a significant difference of survival rate was observed between IOR and control groups (P < 0.05); the mean survival time of the IOR group was 4.6 ± 2.6 (SD) and that of the control group 2.5 ± 1.4 (SD) months. Intraoperative radiotherapy proved to be effective in prolonging the survival of patients with advanced stage of the lesion.
Transplantation | 1986
Kenji Yuzawa; Ikuko Kondo; Katashi Fukao; Yoji Iwasaki; Hideo Hamaguchi
To examine whether cyclosporine (CsA) has mutagenic potential against human cells, we analyzed sister chromatid exchange (SCE) induction by CsA using human lymphocytes in vitro. SCE frequencies increased significantly in the lymphocytes treated with 1 microgram/ml and 5 micrograms/ml CsA, though the frequencies seemed to be less than one hundredth of those induced by mitomycin C (MMC). The value of induced SCE depended on CsA concentration. This result indicates that CsA has SCE inducibility. The data also suggest that CsA has a mutagenic effect on human lymphocytes.
Cancer Immunology, Immunotherapy | 1986
Shohei Koyama; Azusa Ozaki; Yoji Iwasaki; Takao Sakita; Toshiaki Osuga; Akira Watanabe; Masanori Suzuki; Tsuneo Kawasaki; Tetsuo Soma; Takafumi Tabuchi; Muneharu Nakayama; Sumihiko Koizumi; Koichi Yokoyama; Tomohiko Uchida; Kazuo Orii; Tsuneo Tanaka
SummaryWe performed a randomized controlled study of postoperative adjuvant immunochemotherapy with Nocardia rubra cell wall skeleton (N-CWS) and Tegafur for gastric carcinoma between September 1979 and March 1983. A total of 309 patients were entered into this trial. Of the 309 patients, there were 98 evaluable patients in the chemotherapy group and 115 evaluable patients in the immunochemotherapy group. In both groups, Tegafur was given as chemotherapy at a daily dose of 400 to 800 mg, starting at 24–29 days after gastrectomy. In the immunochemotherapy group, 400 μg of N-CWS was injected i. d. within the 2nd postoperative week. It was given weekly during the first month and subsequently monthly for as long as practicable. The patients were surveyed for length of survival in March 1985. The postoperative survival rate was analyzed for all cases, and for patients with various histopathological stages of carcinoma for comparison between the two treatment groups. No statistical difference was detected between the two groups in terms of age, sex, surgical curabilities, or stage of carcinoma. The overall survival rate for all patients was significantly higher in the immunochemotherapy group than in the chemotherapy group (p<0.05). With stage III plus IV disease, 53 patients from the chemotherapy group and 61 patients from the immunochemotherapy group were included for the analysis. As a consequence, a highly significant survival rate was observed in patients with stage III plus IV carcinoma in the immunochemotherapy group (p<0.005) as compared to the chemotherapy group. The overall 5-year (1800 days) survival rate after surgical treatment was 60.2% for the chemotherapy group and 73.2% for the immunochemotherapy group. In patients with stage III plus IV disease, the 5-year survival rates of the two treatment groups were 28.8% and 52.4%, respectively. Accordingly, the 50% survival period of patients with stage III plus IV cancer was 1800 days or more in the immunochemotherapy group, whereas it was only 722 days in the chemotherapy group. These results emphasize the effectiveness of N-CWS as an adjuvant immunotherapeutic agent in postoperative gastric cancer patients.The main side effects of N-CWS were skin lesions in the injected sites and fever, but these were temporary and not serious.
Surgery Today | 1985
Yasuhiro Takase; Masanori Kikuchi; Azusa Ozaki; Susumu Shibuya; Yoji Iwasaki
Injection sclerotherapy is one of the most effective treatments for esophageal varices. To investigate the fate of esophageal varices embolized with a sclerosant (ethanolamine oleate), we have examined at autopsy the esophageal wall of 14 patients with esophageal varices. When the sclerosant was injected into the varices, at first thrombi formed. After two weeks, granulation tissue appeared and the thrombi were gradually replaced. The granulation tissues were organized slowly after 3 months and in the organized granulation tissue, microscopic recanalization of vessels were seen in 8 out of 9 cases. There was no recurrence of the original varices andde novo varices occurred in one patient. These observations indicate that the varices embolized with ethanolamine oleate become organized in three months after the treatment, and accordingly the esophageal varices are cured. It became also clear that recurrence of the original varices did not occur after the organization.
Thrombosis Research | 1983
Akio Ishikawa; Yoji Iwasaki
Hypercoagulability and DIC are characterized by the presence of SFMC in plasma. We have devised a more rapid method with a quantitative estimation of SFMC by use of HPLC. The normal percentage of SFMC of total fibrinogen content was 2.2 +/- 0.8% in plasma. On the other hand, the amount of SFMC in DIC patients showed a level of 6.8% to 16.7%. The level of SFMC in the third postoperative day after gastrointestinal surgery was between 2.3% and 6.1%. These moderately elevated SFMC levels were suggested to be due to the state of hypercoagulability. Thus, the measurement of SFMC with HPLC is a very useful method to analyze hypercoagulability and DIC.
Journal of Gastroenterology and Hepatology | 1991
Akio Ishikawa; Katashi Fukao; Einosuke Tanaka; Katsuhisa Tsuji; Akira Osada; Yuji Yamamoto; T. Kiyosawa; Yoji Iwasaki
The quantitative estimation of the hepatic functional volume in rats was attempted using the serum dimethadione (DMO)/trimethadione (TMO) ratio in a single blood sampling after oral administration of TMO, which we call the TMO tolerance test, in order to develop a means of pre‐operatively assessing hepatic resectability.
Surgery Today | 1978
Takenori Ochiai; Hiroshi Amemiya; Kazuo Watanabe; Hiroshi Sato; Akio Kobayashi; Hirotaka Takizawa; Yoji Iwasaki
SummaryTwo cases of Noca dia asteroides infection were encountered out of 55 kidney transplant patients at Chiba University Hospital. One patient developed an extrapleural abscess and the other had a pulmonary infiltration with chest wall abscess. The patients were successfully treated by surgical drainage of the chest wall abscesses and by oral administration of minocycline. No adverse effects caused by minocycline were observed during the therapy.From 1900, when the first case of Nocardia infection was reported in Japan, there have been 60 cases reported in Japanese literature through 1973, including those we observed. This is the first report on nocardiosis in kidney transplant patients and on successful treatment of nocardiosis with minocycline in Japan.
Digestive Endoscopy | 1990
Niranjan Sharma; Yasuhiro Takase; Susumu Shibuya; Yoji Iwasaki
Survival period, causes of death and variceal rebleeding in 20 patients with esophageal varices associated with hepatocellular carcinoma and liver cirrhosis were analyzed to evaluate the effectiveness of injection sclerotherapy. The first injection sclerotherapy successfully stopped active variceal bleeding in all seven emergency cases. These were followed up as elective cases later on. The remaining 13 patients, who had a history of variceal bleeding, were treated as elective cases from the beginning. Endoscopic evaluation of the varices was performed at intervals of six months to one year, after the first sclerotherapy, and recurrence was treated by elective sclerotherapy. 85% of the patients died within one year. Three out of 20 cases were still alive until this study was performed. But, whereas 17 patients died mainly due to hepatic failure and hepatocellular carcinoma, only one patient died due to variceal rebleeding. No deaths were observed to have been directly due to sclerotherapy or its complications. Hence we think that injection sclerotherapy should be considered one of the treatments for esophageal varices in patients with hepatocellular carcinoma and liver cirrhosis.
Surgery Today | 1988
Yasuhiro Takase; Susumu Shibuya; Azusa Ozaki; Yoji Iwasaki
Fifteen patients with esophageal carcinoma received the Photosensitizing dye Eosin Yellow (10 mg/kg) intravenously prior to surgery, and their para-esophageal lymph nodes were then examined for fluorescence using a laser beam at the time of operation. When the time interval between the injection of Eosin Yellow and the operation was 48 hours, 21 out of 22 (95.4 per cent) metastatic lymph nodes exhibited fluorescence and 25 out of 26 (96.2 per cent) non-metastatic lymph nodes did not exhibit fluorescence. This method proved to be invaluable for detecting metastatic lymph nodes macroscopically at the time of surgery for esophageal carcinoma.