Updated on 2024/11/10

写真a

 
NAGAI Takahiro
 
Organization
University Medical and Dental Hospital Department of genome medicine . Specially Appointed Assistant Professor
Title
Specially Appointed Assistant Professor
External link

Degree

  • 博士(医学) ( 2023.3   新潟大学 )

  • 学士(医学) ( 2015.3   新潟大学 )

Research History

  • Niigata University   University Medical and Dental Hospital   Specially Appointed Assistant Professor

    2023.4

Qualification acquired

  • Doctor

 

Papers

  • Clinical significance of metastatic tumor deposit foci in rectal cancer in the lateral pelvic lymph node area.

    Daisuke Yamai, Yoshifumi Shimada, Masato Nakano, Hikaru Ozeki, Akio Matsumoto, Kaoru Abe, Yosuke Tajima, Mae Nakano, Hiroshi Ichikawa, Jun Sakata, Takahiro Nagai, Yiwei Ling, Shujiro Okuda, Gen Watanabe, Hitoshi Nogami, Satoshi Maruyama, Yasumasa Takii, Toshifumi Wakai

    International journal of clinical oncology   28 ( 10 )   1388 - 1397   2023.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    BACKGROUND: Although previous studies have demonstrated that tumor deposits (TDs) are associated with worse prognosis in colon cancer, their clinical significance in rectal cancer has not been fully elucidated, especially in the lateral pelvic lymph node (LPLN) area. This study aimed to clarify the clinical significance of TDs, focusing on the number of metastatic foci, including lymph node metastases (LNMs) and TDs, in the LPLN area. METHODS: This retrospective study involved 226 consecutive patients with cStage II/III low rectal cancer who underwent LPLN dissection. Metastatic foci, including LNM and TD, in the LPLN area were defined as lateral pelvic metastases (LP-M) and were evaluated according to LP-M status: presence (absence vs. presence), histopathological classification (LNM vs. TD), and number (one to three vs. four or more). We evaluated the relapse-free survival of each model and compared them using the Akaike information criterion (AIC) and Harrell's concordance index (c-index). RESULTS: Forty-nine of 226 patients (22%) had LP-M, and 15 patients (7%) had TDs. The median number of LP-M per patient was one (range, 1-9). The best risk stratification power was observed for number (AIC, 758; c-index, 0.668) compared with presence (AIC, 759; c-index, 0.665) and histopathological classification (AIC, 761; c-index, 0.664). The number of LP-M was an independent prognostic factor for both relapse-free and overall survival, and was significantly associated with cumulative local recurrence. CONCLUSION: The number of metastatic foci, including LNMs and TDs, in the LPLN area is useful for risk stratification of patients with low rectal cancer.

    DOI: 10.1007/s10147-023-02391-1

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  • Deep learning classification of urinary sediment crystals with optimal parameter tuning. International journal

    Takahiro Nagai, Osamu Onodera, Shujiro Okuda

    Scientific reports   12 ( 1 )   21178 - 21178   2022.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    The examination of urinary sediment crystals, the sedimentary components of urine, is useful in screening tests, and is always performed in medical examinations. The examination of urinary sediment crystals is typically done by classifying them under a microscope. Although automated analyzers are commercially available, manual classification is required, which is time-consuming and varies depending on the technologist performing the test and the laboratory. A set of test images was created, consisting of training, validation, and test images. The training images were transformed and augmented using various methods. The test images were classified to determine the patterns that could be correctly classified. Convolutional neural networks were used for training. Furthermore, we also considered the case where the crystal subcategories were not treated as separate. Learning with all parameters except the random cropping parameter showed the highest accuracy value. Treating the subcategories together or separately did not seem to affect the accuracy value. The accuracy of the best pattern was 0.918. When matched to a real-world case, the percentage of correct answers was 88%. Although the number of images was limited, good results were obtained in the classification of crystal images with optimal parameter tuning. The parameter optimization performed in this study can be used as a reference for future studies, with the goal of image classification by deep learning in clinical practice.

    DOI: 10.1038/s41598-022-25385-x

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  • Reevaluating hybrid neurofibroma/schwannoma: Predominance of schwannoma features despite CD34 positivity and initial neurofibroma diagnosis. International journal

    Tatsuya Katsumi, Ryota Hayashi, Shingo Takei, Osamu Ansai, Sumiko Takatsuka, Tatsuya Takenouchi, Kyota Saito, Kazuaki Suda, Kosuke Yoshihara, Takahiro Nagai, Shujiro Okuda, Takaya Fukumoto, Shin-Ichi Ansai, Anna Nakamura, Koji Katsuumi, Takashi Ariizumi, Akira Ogose, Hiroyuki Kawashima, Riichiro Abe

    The Journal of dermatology   51 ( 11 )   1461 - 1469   2024.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    Schwannomas consist of both high-cellularity regions (Antoni A area) and hypocellular regions (Antoni B area) in histopathological findings. Neurofibromas characteristically consist of CD34 positive spindle cells with thin, wavy, nuclei and wavy collagen bands. Previous reports have described segments of schwannomas with neurofibroma features as hybrid tumors, although hybrid tumors were diagnosed based on partial CD34 positivity in many previous reports. On the other hand, the Antoni B area of some schwannomas was reported to be positive for CD34. Therefore, the definition of a hybrid tumor has not been clear. The objective of this study was to determine whether only CD34 positive findings in schwannomas could be used to define a hybrid tumor. In the analysis of our patient with schwannomatosis caused by a novel LZTR1 germline mutation, part of the tumor had CD34 positive hypocellular regions. These regions contained no thin, wavy, nuclei, indicating an Antoni B area. Laser microdissection was used to investigate the genetic background and differences in molecular mechanisms between CD34 positive and CD34 negative regions. All mutations identified in CD34 positive regions were also found in CD34 negative regions. Our data could not clear the genetic background of Antoni B which was CD34 positive area. We then reviewed the pathologies of 66 sporadic schwannomas. Histopathological examinations of all schwannomas revealed the absence of thin, wavy, nuclei and wavy collagen bands, and no hybrid tumors were found in any of the cases. Ten of 66 patients were randomly selected for CD34 immunostaining and positivity was found in all cases. Our data suggest that it is difficult to distinguish schwannomas by staining for CD34 alone, as Antoni B areas can also be positive for CD34. Therefore, CD34 staining alone should not be used to diagnose hybrid tumors in patients with schwannomas.

    DOI: 10.1111/1346-8138.17343

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  • Mucin phenotype and genetic alterations in non-V600E BRAF-mutated colorectal cancer

    Hikaru Ozeki, Yoshifumi Shimada, Mae Nakano, Shuhei Kondo, Riuko Ohashi, Yamato Miwa, Daisuke Yamai, Akio Matsumoto, Kaoru Abe, Yosuke Tajima, Hiroshi Ichikawa, Jun Sakata, Yasumasa Takii, Mika Sugai, Takahiro Nagai, Yiwei Ling, Shujiro Okuda, Toshifumi Wakai

    Human Pathology   2024.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.humpath.2024.02.009

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  • 人工知能 深層学習による画像処理技術の医療への応用

    永井 貴大, 奥田 修二郎

    新潟医学会雑誌   137 ( 2 )   39 - 45   2023.2

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    Language:Japanese   Publisher:新潟医学会  

    脳の視覚野にヒントを得て考案された深層学習ネットワークによる画像処理技術への医療への応用が期待されている.深層学習は,コンピュータの発展による扱えるデータ量の増大によって発展し,複雑な課題を精度よくこなす技術が開発されている.しかし,深層学習の医療への応用には,データの収集の困難さをはじめとした,いくつかの問題点がある.本稿では,データの前処理で精度向上を試みた著者らの取り組みとともに,深層学習による画像処理技術の発展と今後の展望について紹介する.(著者抄録)

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  • Coexistence of Hereditary Spastic Paraplegia Type 4 and Narcolepsy: A Case Report. International journal

    Takahiro Nagai, Yoko Sunami, Risa Kato, Megumi Sugai, Makoto Takahara, Kentaro Ohta, Hidehiko Fujinaka, Kiyoe Goto, Osamu Okanura, Takashi Nakajima, Tetsuo Ozawa

    Case reports in neurology   13 ( 1 )   84 - 91   2021

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    Language:English  

    Spastic paraplegia type 4 (SPG4) is the most common type of hereditary spastic paraplegia (HSP) caused by the mutations in the SPAST gene, which encodes a microtubule-severing protein named spastin. Spastin regulates the number and mobility of microtubules and is essential for axonal outgrowth and neuronal morphogenesis. Herein, we report a patient with SPG4 harboring a novel donor splice site mutation in the SPAST gene (c.1616+1dupG). Although SPG4 usually manifests itself as a pure form of HSP, this patient exhibited a slow progressive cognitive decline and also developed narcolepsy type 2 (narcolepsy without cataplexy) prior to the onset of SPG4. Recently, cognitive decline has attracted attention as a main non-motor symptom of SPG4. However, this is the first reported case of a patient developing both SPG4 and narcolepsy, although it remains unclear whether the manifestation of the two diseases is a coincidence or an association. In this report, we describe the clinical symptoms and genetic background of the patient.

    DOI: 10.1159/000512404

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  • Role of RNF213 p.4810K variant in the development of intracranial arterial disease in patients treated with nilotinib. International journal

    Masahiro Uemura, Masato Kanazawa, Takuma Yamagishi, Takahiro Nagai, Mami Takahashi, Shingo Koide, Masayoshi Tada, Junsuke Shimbo, Aiko Isami, Kunihiko Makino, Masayoshi Masuko, Kouji Nikkuni, Kouichirou Okamoto, Shuichi Igarashi, Kenichi Morita, Osamu Onodera

    Journal of the neurological sciences   408   116577 - 116577   2020.1

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  • 救急搬送される患者数とそれを診る日当直研修医との統計学的検討

    永井 貴大

    長岡赤十字病院医学雑誌   30 ( 1 )   45 - 48   2017.12

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    Language:Japanese   Publisher:長岡赤十字病院  

    2015年12月から2016年11月迄に初期研修医10名が、休日当番日の日当直、平日当番日の当直を何回行ったか検討した。調査対象期間における当番日は124日であった。調査対象期間における休日当番日の日当直及び平日当番日の当直時間帯に来院した救急車数の合計は1710台であった。当直1回あたり救急車数は13.375~14.556台で、全研修医の当直は13.790台と推定した。

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  • Development and external validation of a nomogram for overall survival after curative resection in serosa-negative, locally advanced gastric cancer. International journal

    S Hirabayashi, S Kosugi, Y Isobe, A Nashimoto, I Oda, K Hayashi, I Miyashiro, S Tsujitani, Y Kodera, Y Seto, H Furukawa, H Ono, S Tanabe, M Kaminishi, S Nunobe, T Fukagawa, R Matsuo, T Nagai, H Katai, T Wakai, K Akazawa

    Annals of oncology : official journal of the European Society for Medical Oncology   25 ( 6 )   1179 - 84   2014.6

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    BACKGROUND: Few nomograms can predict overall survival (OS) after curative resection of advanced gastric cancer (AGC), and these nomograms were developed using data from only a few large centers over a long time period. The aim of this study was to develop and externally validate an elaborative nomogram that predicts 5-year OS after curative resection for serosa-negative, locally AGC using a large amount of data from multiple centers in Japan over a short time period (2001-2003). PATIENTS AND METHODS: Of 39 859 patients who underwent surgery for gastric cancer between 2001 and 2003 at multiple centers in Japan, we retrospectively analyzed 5196 patients with serosa-negative AGC who underwent Resection A according to the 13th Japanese Classification of Gastric Carcinoma. The data of 3085 patients who underwent surgery from 2001 to 2002 were used as a training set for the construction of a nomogram and Web software. The data of 2111 patients who underwent surgery in 2003 were used as an external validation set. RESULTS: Age at operation, gender, tumor size and location, macroscopic type, histological type, depth of invasion, number of positive and examined lymph nodes, and lymphovascular invasion, but not the extent of lymphadenectomy, were associated with OS. Discrimination of the developed nomogram was superior to that of the TNM classification (concordance indices of 0.68 versus 0.61; P < 0.001). Moreover, calibration was accurate. CONCLUSIONS: We have developed and externally validated an elaborative nomogram that predicts the 5-year OS of postoperative serosa-negative AGC. This nomogram would be helpful in the assessment of individual risks and in the consideration of additional therapy in clinical practice, and we have created freely available Web software to more easily and quickly predict OS and to draw a survival curve for these purposes.

    DOI: 10.1093/annonc/mdu125

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