Tatsumasa Ando
Gunma University
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Publication
Featured researches published by Tatsumasa Ando.
Cancer Chemotherapy and Pharmacology | 1994
Yuichi Iino; Yoshiki Takai; Tatsumasa Ando; Susumu Ohwada; Takao Yokoe; Noritaka Sugamata; Hiroyuki Takei; Jun Horiguchi; Koutarou Iijima; Yasuo Morishita
TAT-59 {(E)-4-[1-[4-[2-(dimethylamino)ethoxy]-phenyl]-2-(4-isopropyl)phenyl-1-butenyl]-phenyl-monophosphate} treatment was performed on hormone-dependent MCF-7 tumors in athymic mice. TAT-59 given at 1, 5, and 20 mg/kg inhibited the estrogen-stimulated growth of MCF-7 tumors in athymic mice in a dose-dependent fashion. The most clear decrease in tumor growth was shown in the TAT-59 alone group, although it was not dramatic. Average serum concentrations of DP-TAT-59 {(Z)-[1-[4-[2-(dimethylamino)-ethoxy]phenyl]-2-(4-isopropyl)phenyl-1-butenyl]-4-hydroxybenzene} and DM-DP-TAT-59(desmethyl-DP-TAT-manner. Much higher levels of DP-TAT-59 and DM-DP-TAT-59 wer shown in tumors (target tissues of estrogen) as compared with muscles (nontarget tissues of estrogen) or serum. A serum concentration of DP-TAT-59 or DM-DP-TAT-59 corresponding to the physiologic levels of serum estradiol in premenopausal women was sufficient to inhibit the estrogen-stimulated growth of MCF-7 tumors in mice. TAT-59 induced a dose-dependent increase in estrogen receptor levels in the MCF-7 tumors. In contrast, it prevented the estradiol (E2)-induced increase in progesterone receptor levels in a dose-dependent manner. Insulin-like growth factor 1 levels measured in the MCF-7 tumors significantly decreased in the TAT-59 alone group and in the no treatment group as compared with the E2 alone group. These results show the pronounced antiestrogenic action of TAT-59 on hormone-dependent MCF-7 tumors in athymic mice.
Cancer Chemotherapy and Pharmacology | 1993
Yuchi Iino; Yoshiki Takai; Tatsumasa Ando; Noritaka Sugamata; Michio Maemura; Takeshi Takeo; Susumu Ohwada; Yasuo Morishita
Toremifene given in different sizes of silastic capsules was used to treat MCF-7 tumors in athmic mice. Toremifene inhibited the estradiol-stimulated growth of MCF-7 tumors in athymic mice. Average serum concentrations of toremifene obtained using a sustained-release preparation of the drug (in 0.5-, 1.0-, and 2.0-cm silastic capsules) increased gradually in a capsule-size-dependent fashion. Much higher levels of toremifene orN-demethyltoremifene were detected in tumors(target tissues of estrogen) as compared with muscles (non-target tissues of estrogen). The concentration of toremifene in serum (i.e., 10–30 ng ml−1) was sufficient to inhibit the estrogen-stimulated growth of MCF-7 tumors at physiological (i.e., 200–400 pg ml−1) serum estradiol concentrations in premenopausal women. No significant difference in estrogen receptor (ER) levels was found between the estradiol-alone group and the toremifene-treated groups. However, the ER levels in the toremifene-alone group and the no-treatment group (no toremifene or estradiol) tended to increase as compared with the estradiol-alone group. Toremifene blocked the estradiol-induced increase in progesterone receptor levels in a dose-dependent fashion. Insulin-like growth factor-1 (IGF-1) levels in the MCF-7 tumors significantly decreased in the toremifene-alone group as compared with the estradiol-alone group. These results show the antiestrogenic action of toremifene on hormone-dependent MCF-7 tumors in athymic mice.
Breast Cancer | 2002
Jun Horiguchi; Yuichi Iino; Yukio Koibuchi; Takao Yokoe; Hiroyuki Takei; Michitaka Yamakawa; Takashi Nakajima; Tetsunari Oyama; Tatsumasa Ando; Tsunehiro Ishida; Keiichi Endo; Yoshiki Takai; Hideo Suzuki; Takanao Fujii; Tadahiro Yokomori; Yasuo Morishita
BackgroundBreast-conserving therapy has been widely utilized as a treatment option for women with early breast cancer. However, no randomized study comparing modified radical mastectomy and breast-conserving therapy has been conducted in Japan.MethodsTwo hundred and twenty-eight Japanese women with early breast cancer enrolled in the Gunma Breast Conserving Therapy Study between 1991 and 1994 were examined to determine whether there is any difference in disease-free survival or overall survival between radical mastectomy and breast-conserving therapy. After informed consent was obtained, a total of 119 patients underwent breast-conserving therapy and 109 underwent mastectomy.ResultsMastectomy was a more frequently utilized treatment than breast-conserving therapy in patients with clinical stage II lesions, older age, larger tumor size or shorter distance between tumor and nipple. The mean follow-up period for all patients was 81 months (median 86 months). There was no significant difference in overall survival or disease-free survival between breast-conserving therapy and mastectomy even after adjusting for the clinical stage of the disease. A multivariate analysis of tumor size, lymph node status, estrogen receptor status and operation method using the Cox proportion hazard model confirmed that only lymph node status was an independent prognostic factor.ConclusionBreast-conserving therapy is comparable to modified radical mastectomy in overall survival and disease-free survival.
Asian Journal of Endoscopic Surgery | 2014
Takuya Shiraishi; Naoki Tomizawa; Tatsumasa Ando; Kazuhisa Arakawa; Katsumi Kobayashi; Ken Muroya; Ryo Kurosaki; Hiroaki Sato; Yuji Suto; Ryuji Kato; Naoya Ozawa; Yutaka Sunose; Izumi Takeyoshi
Extraperitoneal colostomy is considered to be more effective at preventing post‐colostomy complications than intraperitoneal colostomy. However, this operation is difficult via laparoscopic surgery alone. We present an extraperitoneal colostomy technique using a hand inserted from the perineal side.
journal of Clinical Case Reports | 2016
Yoshiaki Takase; Naoki Tomizawa; Yasuaki Enokida; Takuya Shiraishi; Ryuji Katoh; Yujin Suto; Hiroaki Sato; Ken Muroya; Ryo Kurosaki; Katsumi Kobayashi; Kazuhisa Arakawa; Tatsumasa Ando; Izumi Takesyohi
A 61-year-old woman was diagnosed with right inguinal lymph node and splenic metastasis of ovarian serous cystadenocarcinoma. We performed right inguinal lymph node dissection and total laparoscopic splenectomy in the supine position followed by transvaginal specimen extraction (TVSE). First, using three ports, we extracted the right inguinal lymph node. We repaired the posterior wall of the inguinal canal using a mesh plug. We added two ports and displaced the spleen from the retroperitoneum and lifted it using a snake retractor, disconnecting the hilum using an automatic suturing device. Next, the posterior wall of the vagina was intraperitoneally incised and an Alexis® laparoscopic system was inserted into the vagina. The cap maintained aeroperitoneum, a collection bag was inserted in the abdominal cavity via the vagina, and the spleen was collected. When the spleen was removed from the body, partial fragmentation of the organ was required in the bag. Organ fragmentation was performed only within the bag, and we made sure not to tear the bag. The vaginal wound was laparoscopically sutured. The patient had no operative complications and was able to actively ambulate at first day after surgery due to a slight postoperative pain. Total laparoscopic splenectomy with TVSE in the supine position may be a safe and feasible method for selected female patients. This technique enables minimally invasive surgery for female patients with splenic disease.
Surgical Case Reports | 2016
Yoshiaki Takase; Naoki Tomizawa; Yasuaki Enokida; Takuya Shiraishi; Ryuji Katoh; Yujin Suto; Hiroaki Sato; Ken Muroya; Ryo Kurosaki; Katsumi Kobayashi; Kazuhisa Arakawa; Tatsumasa Ando; Izumi Takesyohi
A 61-year-old woman was diagnosed with right inguinal lymph node and splenic metastasis of ovarian serous cystadenocarcinoma. We performed right inguinal lymph node dissection and total laparoscopic splenectomy in the supine position followed by transvaginal specimen extraction (TVSE). First, using three ports, we extracted the right inguinal lymph node. We repaired the posterior wall of the inguinal canal using a mesh plug. We added two ports and displaced the spleen from the retroperitoneum and lifted it using a snake retractor, disconnecting the hilum using an automatic suturing device. Next, the posterior wall of the vagina was intraperitoneally incised. And an Alexis® laparoscopic system was inserted into the vagina. The cap maintained aeroperitoneum, a collection bag was inserted in the abdominal cavity via the vagina, and the spleen was collected. When the spleen was removed from the body, partial fragmentation of the organ was required in the bag. Organ fragmentation was performed only within the bag, and we made sure not to tear the bag. The vaginal wound was laparoscopically sutured. The patient had no operative complications and was able to actively ambulate at the first day after surgery due to a slight postoperative pain. Total laparoscopic splenectomy with TVSE in the supine position may be a safe and feasible method for selected female patients. This technique enables minimally invasive surgery for female patients with splenic disease.
The Journal of Nuclear Medicine | 1998
Shigeko Amano; T. Inoue; Katsumi Tomiyoshi; Tatsumasa Ando; Keigo Endo
Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2006
Daisuke Yoshinari; Tatsumasa Ando; Naoki Tomizawa; Susumu Kawate; Hirofumi Tsutsumi; Izumi Takeyoshi
Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2012
Kazuhisa Arakawa; Tetsushi Ogawa; Tatsumasa Ando; Naoki Tomizawa; Yutaka Sunose; Izumi Takeyoshi
Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2017
Takuhisa Okada; Kazuhisa Arakawa; Yasuaki Enokida; Naoki Tomizawa; Tatsumasa Ando; Munenori Ide