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Dive into the research topics where Yoichiro Kobashi is active.

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Featured researches published by Yoichiro Kobashi.


The American Journal of Surgical Pathology | 1995

Clinicopathologic study of CD56 (NCAM)-positive angiocentric lymphoma occurring in sites other than the upper and lower respiratory tract.

Shigeo Nakamura; Taizan Suchi; Takashi Koshikawa; Kuniyoshi Kitoh; Koichi Koike; Hirokazu Komatsu; Shinsuke Iida; Yoshitoyo Kagami; Michinori Ogura; Eriko Katoh; Soji Kurita; Hisamitsu Suzuki; Yoichiro Kobashi; Hirohiko Yamabe; Norio Hirabayashi; Ryuzo Ueda; Toshitada Takahashi

The expression of the neural cell adhesion molecule (NCAM) (CD56, NKH-1) is a rare phenomenon in malignant lymphoma. Recently, several authors, including our group, described the clinicopathologic, phenotypic, and genotypic features of NCAM-positive tumors as a unique subgroup within a larger category of hematolymphoid malignancies. Ten cases of CD56+ angiocentric lymphoma occurring in sites other than the upper aerodigestive tract were studied for evaluating their characteristics. The disease occurred in six men and four women varying from 24 to 85 years (mean age, 53 years) who often exhibited a striking predilection for extranodal sites of involvement, such as the skin, gastrointestinal tract, and muscle, usually in the absence of peripheral lymphadenopathy. Although the cytologic appearances and immunophenotypic profile varied from case to case, these tumors often exhibited azurophilic granules, an angiocentric growth pattern, and surface CD3−, T-cell receptor (TCR) antigens−, and CD56+ phenotype without B-cell phenotype, except for a single case of CD3+, TCRα/β+, and CD56+ phenotype. Genotypic investigation exhibited germline configuration of the TCR β and γ chain genes and the immunoglobulin heavy chain gene in all five cases of surface CD3− phenotype examined, whereas the case of CD3+ phenotype showed rearrangement of TCRβ. They seem to constitute a distinct entity of the lineage spectrum spanning from natural killer (NK) cell to NK-like T cell.


Cancer | 1990

Extranodal non-Hodgkin's lymphoma of the head and neck. A clinicopathologic study in the kyoto-nara area of japan

Nobuko Shima; Yoichiro Kobashi; Kazushige Tsutsui; Katsuhiko Ogawa; Shunzo Maetani; Yasuaki Nakashima; Kunio Ichijima; Hirohiko Yamabe

The clinicopathologic features of 114 Japanese patients with extranodal non‐Hodgkins lymphoma of the head and neck region were analyzed. The median age was 60.5 years and the male:female ratio was 1.5:1. The most common site of involvement was Waldeyers ring, followed by the oral cavity, thyroid gland, paranasal sinuses, nasal cavity, and larynx. Seventy‐five percent of the patients were in Stage I or Stage II at admission. Histologically, diffuse lymphoma accounted for 94% and follicular lymphoma for 6% of cases. The histologic grade according to the Working Formulation System of the National Cancer Institute was low in 11%, intermediate in 75%, and high in 14% of cases. Immunohistochemical study showed that the majority of the cases were of B‐cell type and only 13 cases (11%) were of the T‐cell type. Peripheral T‐cell lymphomas (eight cases) mainly occurred in the nasopharynx and nasal cavity, whereas four of five thymic T‐cell lymphomas were found in the palatine tonsil. The over‐all 5‐year survival rate was 54%, and the factors affecting survival were sex, histologic grade, T/B phenotype, clinical stage, and the site of initial presentation. Five‐year survival with nasal cavity and Waldeyers ring lymphoma was 24% and 46%, respectively. The poor prognosis of lymphomas at these sites might result from the predominance of T‐cell lymphoma, the paucity of low grade lymphoma, and the relatively high incidence of cases that were in an advanced stage at presentation. In Stage II, patients treated with combined therapy tended to have a better 5year survival rate than those treated with radiotherapy alone.


Histopathology | 1996

Inconsistent association of Epstein-Barr virus with CD56 (NCAM)-positive angiocentric lymphoma occuring in sites other than the upper and lower respiratory tract

Yoichiro Kobashi; Shigeo Nakamura; Yuko Sasajima; Takashi Koshikawa; Yasushi Yatabe; Kuniyoshi Kitoh; Shigeo Mori; Ryuzo Ueda; Hirohiko Yamabe; Taizan Suchi

We previously described nine cases of angiocentric lymphoma of a possible natural killer (NK)‐cell lineage with a surface CD3− CD56+ phenotype occurring in sites other than the upper and lower respiratory tract. This study was performed to investigate the association of Epstein‐Barr virus (EBV) with these lymphomas, using the polymerase chain reaction (PCR) for the presence of EBV‐DNA, in situ hybridization (ISH) for EBV‐encoded small RNAs (EBERs) and immunohistology for EBV‐determined nuclear antigen‐2 (EBNA‐2) and latent membrane protein‐1 (LMP‐1) in paraffin sections. PCR and ISH produced almost identical results, and EBERs were identified in the nuclei of the lymphoma cells of three cases, two of which exhibited LMP‐1 in the cytoplasm of tumour cells without EBNA‐2 expression. Molecular genetic analysis revealed EBV to be incorporated into these three EBER‐positive cases either clonally or biclonally. It was revealed by re‐evaluation of their morphology with the established EBV status on each case that, in contrast to the rather variable and irregular cellular composition of the EBV‐ positive tumours, the EBV‐negative tumours stood out because of their remarkably uniform ‘blastoid’ appearance, and could be grouped as blastic NK‐cell lymphoma. The relationship of the EBV‐positive cases with nasal NK‐cell tumours has yet to be clarified.


The American Journal of Surgical Pathology | 2008

Lung involvement in IgG4-related lymphoplasmacytic vasculitis and interstitial fibrosis: report of 3 cases and review of the literature.

Kyoko Yamashita; Hironori Haga; Yoichiro Kobashi; Aya Miyagawa-Hayashino; Akihiko Yoshizawa; Toshiaki Manabe

There have been a few reports on lung diseases associated with an increased number of infiltrating IgG4-positive plasma cells or lung involvement of IgG4-related sclerosing disease, although their characteristic histologic features have not been well described. Herein, we present 3 cases of interstitial lung disease with common histology and abundant IgG4-positive cell infiltration. Patient 1, a 65-year-old man, was incidentally noted to have a nodular lesion in the left hilar region. In patient 2, a 78-year-old man with dyspnea on effort, computed tomography revealed multifocal consolidation adjacent to the pleura in both lower lobes. Patient 3, a 74-year-old man, underwent lung biopsy for right-sided pleural effusion of unknown etiology. The histologic findings of the 3 individuals were characterized by expansion of the interstitium by dense lymphoplasmacytic infiltrate with prominent vascular involvement, which was indistinguishable from grade 1 lesion of lymphomatoid granulomatosis (LYG-G1). In situ hybridization for Epstein-Barr virus-encoded small RNA (EBER) revealed few or no EBER-positive lymphocytes. Vascular involvement showed subendothelial lymphoplasmacytic infiltrate, including numerous IgG4-positive plasma cells. The percentages of IgG4-positive to IgG-positive plasma cells were 85%, 47%, 46%, respectively. Similar vascular lesions have been described in previous reports of lung complications in IgG4-related sclerosing diseases. Some of these lesions were diagnosed as LYG-G1 without EBER-positive cells. In conclusion, LYG-G1–like lesion characterized by lymphoplasmacytic vasculitis might be a characteristic feature of IgG4-related lung disease.


Journal of The American Academy of Dermatology | 1990

Aleukemic leukemia cutis

Sayoko Ohno; Tadashi Yokoo; Miyuki Ohta; Masamitsu Yamamoto; Kiichiro Danno; Noriyuki Hamato; Keisuke Tomii; Yohichiroh Ohno; Yoichiro Kobashi

A 39-year-old man had multiple nodules on the skin. The appearance of atypical monocytes in a skin biopsy specimen preceded the onset of overt acute monocytic leukemia by 14 months.


Cancer | 1983

Malignant chondroid syringoma. Report of a case with widespread metastasis and review of pertinent literature

Eiji Ishimura; Hirofumi Iwamoto; Yoichiro Kobashi; Hirohiko Yamabe; Kunio Ichijima

The authors report the autopsy case of a 73‐year‐old man with widespread, metastatic, malignant chondroid syringoma, with a long clinical history. Three years after resection of the primary tumor on the back, the tumor recurred at the same site, metastasized to the cervical lymph nodes 7 years later, and finally, after 13 years exhibited widespread metastases. Histologically, the tumor showed cords and nests of cuboidal or polygonal tumor cells with little cellular pleomorphism and few mitoses surrounded by a mucoid matrix. Histochemically, the matrix contained hyaluronic acid and sulfated acid mucopolysaccharides, such as chondroitin sulfate A and/or C. To the knowledge of the authors there have been nine reported cases of malignant chondroid syringoma in the English literature, four of which had distant metastasis. A review of the literature reveals that malignant chondroid syringoma is more common in women and occurs most often in trunk and extremities, which is in contrast to its benign counterpart, its histologic appearances vary greatly, and it may even have benign appearances.


Respiratory Medicine | 2011

Detection of antisynthetase syndrome in patients with idiopathic interstitial pneumonias

Kizuku Watanabe; Tomohiro Handa; Kiminobu Tanizawa; Yuji Hosono; Yoshio Taguchi; Satoshi Noma; Yoichiro Kobashi; Takeshi Kubo; Kensaku Aihara; Kazuo Chin; Sonoko Nagai; Tsuneyo Mimori; Michiaki Mishima

OBJECTIVES Antisynthetase syndrome (ASS) is characterized by autoantibodies to aminoacyl-tRNA synthetases (anti-synthetase) and it is frequently associated with interstitial lung disease. The purpose of this study was to elucidate the prevalence and characteristics of the anti-synthetase positive subpopulation among idiopathic interstitial pneumonias (IIPs) and to clarify the importance of screening for these antibodies. METHODS A retrospective study was performed in 198 consecutive cases with IIPs. Screening for six anti-synthetase antibodies was performed in all cases. Clinical profiles of all cases were compared with reference to the presence of anti-synthetase. High-resolution computed tomography (HRCT) findings of anti-synthetase positive cases were also analyzed. RESULTS 13 cases (6.6%) were positive for anti-synthetase. Anti-EJ was most prevalent, followed by anti-PL-12. Onset ages of anti-synthetase positive cases were younger than those of anti-synthetase negative cases. Extrapulmonary features of ASS were absent in 6 anti-synthetase positive cases (46.2%). Histologically, among 5 UIP with lymphoid follicles and 11 NSIP cases, the prevalence of anti-synthetase positive cases was 8/16 (50%). On HRCT, ground glass opacity and traction bronchiectasis were the major findings in anti-synthetase positive cases, while honeycombing was absent. CONCLUSIONS Anti-synthetase positive cases were not rare among IIPs. Anti-synthetase should be screened for in IIPs, especially in pathological NSIP or UIP with lymphoid follicles. These patients should be screened for anti-synthetase even if no suggestive extrapulmonary manifestation exists.


The Journal of Pathology | 2003

Sustained interleukin-6 signalling leads to the development of lymphoid organ-like structures in the lung

Sho Goya; Hiroto Matsuoka; Masahide Mori; Hiroshi Morishita; Hiroshi Kida; Yoichiro Kobashi; Terufumi Kato; Yoshio Taguchi; Tadashi Osaki; Isao Tachibana; Kazuyuki Yoshizaki; Ichiro Kawase; Seiji Hayashi

A variety of pathological changes are seen in lymphoproliferative disorders of the lung but the histogenesis of these abnormalities is not yet fully understood. We previously showed that adenovirus vector‐mediated transient expression of both the human interleukin‐6 (IL‐6) and IL‐6 receptor (IL‐6R) genes, but not the IL‐6 gene alone, in the rat lung induced lymphocytic alveolitis. In the present study, we explored the lung pathology of human IL‐6 and IL‐6R double transgenic mice to elucidate the effects of prolonged IL‐6 signalling on the lung. The transgenic animals developed mononuclear cell accumulation in peribronchovascular regions, but little infiltration into alveolar spaces. Immunohistochemical analysis revealed that the cellular accumulations contained not only mixtures of inflammatory cells but also lymphoid tissue‐like structures. As the expression of CXCL13/BLC, the indispensable chemokine for lymphoid organogenesis, was recognized in the B cell follicles of the pulmonary lesions, we speculate that this chemokine plays an inductive role in the development of the lymphoid tissue‐like structures. These structures were distinguished from bronchus‐associated lymphoid tissues (BALTs) by their location and by the lack of lymphoepithelium, which is a characteristic of BALT. These findings imply that IL‐6 signalling may play a role in the pathogenesis of lymphoproliferative disorders of the lung. Copyright


Pancreas | 1998

Carcinoma In Situ of the Pancreas Associated with Localized Fibrosis : A Clue to Early Detection of Neoplastic Lesions Arising from Pancreatic Ducts

Kyoichi Takaori; Satoru Matsusue; Takahisa Fujikawa; Yoichiro Kobashi; Takahiro Ito; Yoshihiro Matsuo; Hajime Oishi; Hiroshi Takeda

1. Weaver CH. Mucocele of the appendix with pseudomucinous degeneration. Am J Surg 1937;36:523-6. 2. Femandez RN, Daly JM. Pseudomyxoma peritonei. Arch Surg 1980;115:409-14. 3. Shanks HGI. Pseudomyxoma peritonei. J Obstet Gynaecol Br Commonw 196 I ;68:2 12-24. 4. Jones DH. Pseudomyxoma peritonei. Br J Clin Pract 1965;19: 675-80. 5 . Chejfec G, Rieker WJ, Jablokow VR, Could VE. Pseudomyxoma peritonei associated with colloid carcinoma of the pancreas. Gastroenterology 1986;90:202-5. 6. Santini D, Campione 0, Salerno A, et al. Intraductal papillar-mucinous neoplasm of the pancreas. A clinicopathological entity. Arch Parhol Lab Med 1995;119:209-13. 7. Sandenbergh HA, Woodruff ID. Histogenesis of pseudomyxoma peritonei: review of nine cases. Obsret Gynecol 1977;49:339-45. 8. Mann WJ, Wagner J, Chumas J, Chalas E. The management of pseudomyxoma peritonei. Cancer 1990;66: 163HO. 9. Novel1 A. Role of surgery in the treatment of pseudomyxoma peritonei. J R Coll Surg Edinb 1990:35:21-3.


Journal of Magnetic Resonance Imaging | 2002

Proton two-dimensional chemical shift imaging for evaluation of prostate cancer: External surface coil vs. endorectal surface coil

Yasushi Kaji; Akihiko Wada; Izumi Imaoka; Michimasa Matsuo; Toshiro Terachi; Yoichiro Kobashi; Kazuro Sugimura; Masahiko Fujii; Katsuya Maruyama; Osamu Takizawa

To compare the diagnostic ability of proton magnetic resonance spectroscopy (MRS) using an external surface coil with that using an endorectal surface coil in patients with prostate cancer.

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