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7 results on '"Osamu Shiina"'

1. Differentiation grade as a risk factor for lymph node metastasis in T1 colorectal cancer

Author

Osamu Shiina, Shin‐ei Kudo, Katsuro Ichimasa, Yuki Takashina, Yuta Kouyama, Kenichi Mochizuki, Yuriko Morita, Takanori Kuroki, Shun Kato, Hiroki Nakamura, Shingo Matsudaira, Masashi Misawa, Noriyuki Ogata, Takemasa Hayashi, Kunihiko Wakamura, Naruhiko Sawada, Toshiyuki Baba, Tetsuo Nemoto, Fumio Ishida, and Hideyuki Miyachi

Subjects
colorectal neoplasms, endoscopic mucosal resection, lymph nodes, neoplasm grading, risk factor, Diseases of the digestive system. Gastroenterology, RC799-869
Abstract

Abstract Objectives Japanese guidelines include high‐grade (poorly differentiated) tumors as a risk factor for lymph node metastasis (LNM) in T1 colorectal cancer (CRC). However, whether the grading is based on the least or most predominant component when the lesion consists of two or more levels of differentiation varies among institutions. This study aimed to investigate which method is optimal for assessing the risk of LNM in T1 CRC. Methods We retrospectively evaluated 971 consecutive patients with T1 CRC who underwent initial or additional surgical resection from 2001 to 2021 at our institution. Tumor grading was divided into low‐grade (well‐ to moderately differentiated) and high‐grade based on the least or predominant differentiation analyses. We investigated the correlations between LNM and these two grading analyses. Results LNM was present in 9.8% of patients. High‐grade tumors, as determined by least differentiation analysis, accounted for 17.0%, compared to 0.8% identified by predominant differentiation analysis. A significant association with LNM was noted for the least differentiation method (p < 0.05), while no such association was found for predominant differentiation (p = 0.18). In multivariate logistic regression, grading based on least differentiation was an independent predictor of LNM (p = 0.04, odds ratio 1.68, 95% confidence interval 1.00–2.83). Sensitivity and specificity for detecting LNM were 27.4% and 84.1% for least differentiation, and 2.1% and 99.3% for predominant differentiation, respectively. Conclusions Tumor grading via least differentiation analysis proved to be a more reliable measure for assessing LNM risk in T1 CRC compared to grading by predominant differentiation.

Published
2024
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2. P282 Artificial intelligence for real-time optical diagnosis of neoplastic polyps during colonoscopy

Author

Ishita Barua, Paulina Wieszczy, Shin-ei Kudo, Masashi Misawa, Øyvind Holme, Shraddha Gulati, Sophie Williams, Kensaku Mori, Hayato Itoh, Kazumi Takishima, Kenichi Mochizuki, Yuki Miyata, Kentaro Mochida, Yoshika Akimoto, Takanori Kuroki, Yuriko Morita, Osamu Shiina, Shun Kato, Tetsuo Nemoto, Bu Hayee, Patel Mehul, Nishmi Gunasingam, Alexandra Kent, Andrew Emmanuel, Carl Munck, Jens Nilsen, Stine Hvattum, Svein Frigstad, Petter Tandberg, Magnus Løberg, Mette Kalager, Amyn Haji, Michael Bretthauer, and Yuichi Mori

Published
2022

3. Real-Time Artificial Intelligence–Based Optical Diagnosis of Neoplastic Polyps during Colonoscopy

Author

Ishita Barua, Paulina Wieszczy, Shin-ei Kudo, Masashi Misawa, Øyvind Holme, Shraddha Gulati, Sophie Williams, Kensaku Mori, Hayato Itoh, Kazumi Takishima, Kenichi Mochizuki, Yuki Miyata, Kentaro Mochida, Yoshika Akimoto, Takanori Kuroki, Yuriko Morita, Osamu Shiina, Shun Kato, Tetsuo Nemoto, Bu Hayee, Mehul Patel, Nishmi Gunasingam, Alexandra Kent, Andrew Emmanuel, Carl Munck, Jens Aksel Nilsen, Stine Astrup Hvattum, Svein Oskar Frigstad, Petter Tandberg, Magnus Løberg, Mette Kalager, Amyn Haji, Michael Bretthauer, and Yuichi Mori

Published
2022

4. Secretory Pattern of Inhibin During Estrous Cycle and Pregnancy in African (Loxodonta africana) and Asian (Elephas maximus) Elephants

Author

Natsuki Yuto, Gen Watanabe, Saroch Kaewmanee, Etsuo Narushima, Kentaro Nagaoka, Keisuke Sugimura, Kazuyoshi Taya, Tatsuya Yamamoto, Osamu Shiina, Yuki Yamamoto, Yasushi Mouri, and Masayuki Katayanagi

Subjects
endocrine system, medicine.medical_specialty, media_common.quotation_subject, Luteal phase, Andrology, African elephant, Elephas, Internal medicine, biology.animal, medicine, Ovulation, reproductive and urinary physiology, media_common, Estrous cycle, Pregnancy, biology, urogenital system, Inhibin secretion, General Medicine, biology.organism_classification, medicine.disease, medicine.anatomical_structure, Endocrinology, Animal Science and Zoology, Corpus luteum, hormones, hormone substitutes, and hormone antagonists
Abstract

The ovary of female elephants has multiple corpora lutea (CL) during the estrous cycle and gestation. The previous reports clearly demonstrated that inhibin was secreted from lutein cells as well as granulosa cells of antral follicles in cyclic Asian elephants. The aim of this study is to investigate the inhibin secretion during the pregnancy in African and Asian elephants. Two African elephants and two Asian elephants were subjected to this study. Circulating levels of immunoreactive (ir-) inhibin and progesterone were measured by radioimmunoassay. Four pregnant periods of an African elephant and three pregnant periods of an Asian elephant were analyzed in this study. Circulating levels of ir-inhibin started to increase at 1 or 2 week before the ovulation and reached the peak level 3 or 4 weeks earlier than progesterone during the estrous cycle in both African and Asian elephants. After last luteal phase, the serum levels of ir-inhibin remained low throughout pregnancy in both an African and an Asian elephant. The mean levels of ir-inhibin during the pregnancy were lower than the luteal phase in the estrous cycle despite high progesterone levels were maintained throughout the pregnancy. These results strongly suggest that CL secrete a large amount of progesterone but not inhibin during the pregnancy in elephants.

Published
2011

5. The secretory pattern and source of immunoreactive prolactin in pregnant African (Loxodonta africana) and Asian (Elephas maximus) elephants

Author

Yuki, Yamamoto, Tatsuya, Yamamoto, Natsuki, Yuto, Thomas B, Hildebrandt, Imke, Lueders, Gudrun, Wibbelt, Osamu, Shiina, Yasushi, Mouri, Keisuke, Sugimura, Sayuri, Sakamoto, Saroch, Kaewmanee, Kentaro, Nagaoka, Gen, Watanabe, and Kazuyoshi, Taya

Subjects
Pregnancy, Placenta, Elephants, Animals, Pregnancy, Animal, Female, Prolactin
Abstract

The objective of the present study was to define the secretion of prolactin (PRL) in pregnant African and Asian elephants. Levels of immunoreactive (ir-) PRL in serum and placental homogenates were measured by a heterologous radioimmunoassay (RIA) based on an ovine and human RIA system, and the localization of ir-PRL in the placenta was detected by immunohistochemistry using anti-human PRL. Circulating ir-PRL clearly showed a biphasic pattern during pregnancy in African and Asian elephants. Serum levels of ir-PRL started to increase from the 4 - 6th month of gestation and reached the first peak level around the 11-14th month. A second peak of circulating ir-PRL levels was observed around the 18-20th month of gestation followed by an abrupt decline after parturition. In contrast, in a case of abortion of an African elephant, the second peak of ir-PRL was not observed, and the levels remained low for about four months until parturition. The weight of the fetus delivered at the 17th month of gestation was 23.5 kg, which was quite small compared with normal fetuses in previous reports. Ir-PRL was detected in placental homogenates, and immunolocalization was observed in trophoblasts in both the African and Asian elephants, indicating that the placenta is the source of ir-PRL during pregnancy in elephants. The present results clearly demonstrated that circulating ir-PRL shows a biphasic pattern during normal pregnancy and that the placenta appears to be an important source of circulating ir-PRL during pregnancy in both African and Asian elephants.

Published
2011

6. Secretory pattern of inhibin during estrous cycle and pregnancy in African (Loxodonta africana) and Asian (Elephas maximus) elephants

Author

Yuki, Yamamoto, Natsuki, Yuto, Tatsuya, Yamamoto, Saroch, Kaewmanee, Osamu, Shiina, Yasushi, Mouri, Etsuo, Narushima, Masayuki, Katayanagi, Keisuke, Sugimura, Kentaro, Nagaoka, Gen, Watanabe, and Kazuyoshi, Taya

Subjects
Granulosa Cells, Species Specificity, Corpus Luteum, Pregnancy, Elephants, Radioimmunoassay, Animals, Estrous Cycle, Female, Inhibins, Progesterone
Abstract

The ovary of female elephants has multiple corpora lutea (CL) during the estrous cycle and gestation. The previous reports clearly demonstrated that inhibin was secreted from lutein cells as well as granulosa cells of antral follicles in cyclic Asian elephants. The aim of this study is to investigate the inhibin secretion during the pregnancy in African and Asian elephants. Two African elephants and two Asian elephants were subjected to this study. Circulating levels of immunoreactive (ir-) inhibin and progesterone were measured by radioimmunoassay. Four pregnant periods of an African elephant and three pregnant periods of an Asian elephant were analyzed in this study. Circulating levels of ir-inhibin started to increase at 1 or 2 week before the ovulation and reached the peak level 3 or 4 weeks earlier than progesterone during the estrous cycle in both African and Asian elephants. After last luteal phase, the serum levels of ir-inhibin remained low throughout pregnancy in both an African and an Asian elephant. The mean levels of ir-inhibin during the pregnancy were lower than the luteal phase in the estrous cycle despite high progesterone levels were maintained throughout the pregnancy. These results strongly suggest that CL secrete a large amount of progesterone but not inhibin during the pregnancy in elephants.

Published
2011

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