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Dive into the research topics where Keisuke Hirai is active.

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Featured researches published by Keisuke Hirai.


World Journal of Surgery | 1996

Thyroid Cancer Detected by Ultrasound-Guided Fine-Needle Aspiration Biopsy

Tamotsu Yokozawa; Shuji Fukata; Kanji Kuma; Fumio Matsuzuka; Akira Kobayashi; Keisuke Hirai; Akira Miyauchi; Masahiro Sugawara

Abstract. A greater percentage of thyroid cancers can be detected by ultrasound-guided fine-needle aspiration biopsy (UG-FNAB) than by ordinary FNAB. A group of 678 patients were selected sequentially as having been diagnosed with benign nodules by the conventional FNAB method. We reexamined these patients by UG-FNAB and investigated the types of thyroid cancer that were missed by the conventional FNAB. Of the 678 patients diagnosed with benign nodules (using conventional FNAB), 571 (84.2%) demonstrated the same diagnosis when UG-FNAB was used. The remaining 107 patients (15.8%) studied were suspected of having a malignancy after UG-FNAB had been performed. Surgical specimen histology proved thyroid cancer in 99 of the 107 patients: 93 had papillary carcinoma, 4 had follicular carcinoma, 1 had medullary carcinoma and 1 had anaplastic carcinoma. Two drawbacks were noted when conventional FNAB was used: (1) cancer lesions difficult to palpate (n = 55) (e.g., small cancers with or without benign lesions or cancers associated with Hashimoto’s thyroiditis or Graves’ disease); and (2) palpable cancers with insufficient cell material for analysis (n = 44) (e.g., cystic carcinoma and cancers with calcified lesions. UG-FNAB is a powerful technique for detecting microcancers, cystic carcinomas, cancers associated with benign nodules, Hashimoto’s thyroiditis, or coarse calcifications.


World Journal of Surgery | 2002

Prospective trial of unilateral surgery for nonhereditary medullary thyroid carcinoma in patients without germline RET mutations.

Akira Miyauchi; Fumio Matsuzuka; Keisuke Hirai; Tamotsu Yokozawa; Kaoru Kobayashi; Yasuhiro Ito; Keiichi Nakano; Kanji Kuma; Hitoyasu Futami; Ken Yamaguchi

Although sporadic medullary thyroid carcinoma (MTC) tends to be unicentric and confined to one lobe, total thyroidectomy is usually performed because of the risk of a hereditary or bilateral process. Germline RET mutation analysis can discriminate hereditary MTC and truly sporadic, nonhereditary MTC. We analyzed 72 of 94 patients with MTC to establish the genetic nature and the clinical features of nonhereditary MTC. Since 1996 we have prospectively treated 15 patients with nonhereditary MTC (prospective study group, or PSG) according to a unilateral surgery policy. A group of 22 previously operated patients in whom the nonhereditary nature was established served as controls (retrospective study group, or RSG). Systematic central and ipsilateral neck dissection was performed in both groups. Outcome was assessed using postoperative stimulated serum calcitonin levels; a normal value was considered a biochemical cure. All 24 hereditary MTC patients carried germline RET mutations: 8 of 48 patients with apparently sporadic MTC had the mutations, and 6 of the 8 had bilateral MTC. All 40 patients without mutations had a unilateral tumor. In the RSG group 15 of 22 (68%) patients underwent total thyroidectomy, and the biochemical cure rate was 68%. Although only 3 of 15 (20%) of the PSG patients underwent total thyroidectomy, 12 of the 15 (80%) achieved biochemical cure. Univariate analyses revealed that pathologic node involvement— high T and N stages—was adversely related to biochemical cure. The extent of thyroid resection was not related to biochemical cure. Of 20 patients with node involvement, 10 achieved biochemical cure, indicating the importance of systematic neck dissection. Hemithyroidectomy with systematic central and ipsilateral neck dissection is appropriate surgery for nonhereditary MTC.


Pathology International | 1999

Dipeptidyl peptidase IV (DPP IV/CD26) staining predicts distant metastasis of ‘benign’ thyroid tumor

Keisuke Hirai; Tomio Kotani; Yatsuki Aratake; Sachiya Ohtaki; Kanji Kuma

Because follicular thyroid carcinoma is extremely difficult to diagnose, several cases were encountered which have been rediagnosed as carcinoma due to distant metastasis. In the search for a method of correctly diagnosing ‘benign’ thyroid tumor, dipeptidyl peptidase (DPP) IV immunostaining was applied to 10 cases whose diagnoses had been corrected to follicular thyroid carcinoma because of distant metastases. The positive rate of immunostaining using paraffin sections in the rediagnosed follicular thyroid carcinoma group (7/10) was much higher than that of the control group (1/29), which consisted of 15 cases of follicular thyroid adenoma and 14 cases of nodular hyperplasia. These results suggested that pre‐ or postoperative DPP IV staining is useful for predicting distant metastasis of ‘benign’ thyroid tumor.


Surgery Today | 1984

Spontaneous Remission of Hypercalcemia in a Functioning Parathyroid Cyst

Osamu Ozaki; Masahiko Sakamoto; Yasuki Matsui; Takeshi Notsu; Keisuke Hirai; Tohru Mori

We treated a patient with a hyperfunctioning parathyroid cyst detected incidentally and which disappeared spontaneously. High levels of plasma PTH disappeared after removal of the cystic lesion of the parathyroid gland. Histologically, a secondary pseudocyst resulting from a cystic degeneration of an adenoma was observed. Minor hemorrhage of an unknown cause, within the adenoma, led to the large cystic lesion of the parathyroid gland.


World Journal of Surgery | 1992

Outcome of Long Standing Solitary Thyroid Nodules

Kanji Kuma; Fumio Matsuzuka; Akira Kobayashi; Keisuke Hirai; Sinji Morita; Akira Miyauchi; Shoichi Katayama; Masahiro Sugawara


World Journal of Surgery | 2000

Unilateral surgery supported by germline RET oncogene mutation analysis in patients with sporadic medullary thyroid carcinoma.

Akira Miyauchi; Fumio Matsuzuka; Keisuke Hirai; Tomotsu Yokozawa; Kaoru Kobayashi; Seiji Kuma; Kanji Kuma; Hitoyasu Futami; Ken Yamaguchi


Thyroid | 1998

Correlation of Antithyroglobulin and Antithyroid-Peroxidase Antibody Profiles with Clinical and Ultrasound Characteristics of Chronic Thyroiditis

Junta Takamatsu; Sho Yoshida; Tamotsu Yokozawa; Keisuke Hirai; Kanji Kuma; Nakaaki Ohsawa; Toichiro Hosoya


International Journal of Molecular Medicine | 2002

Expression of p57/Kip2 protein in normal and neoplastic thyroid tissues

Yasuhiro Ito; Hiroshi Yoshida; Keiichi Nakano; Kaoru Kobayashi; Tamotsu Yokozawa; Keisuke Hirai; Fumio Matsuzuka; Nariaki Matsuura; Kanji Kuma; Akira Miyauchi


European Journal of Surgery | 2001

Opposite ansa cervicalis to recurrent laryngeal nerve anastomosis to restore phonation in patients with advanced thyroid cancer.

Akira Miyauchi; Tamotsu Yokozawa; Kaoru Kobayashi; Keisuke Hirai; Fumio Matsuzuka; Kanji Kuma


Thyroid | 1999

Differences Between Changes in Serum Thyrotropin-Binding Inhibitory Antibodies and Thyroid-Stimulating Antibodies in the Course of Antithyroid Drug Therapy for Graves' Disease

Yuriko Yamano; Junta Takamatsu; Sadaki Sakane; Keisuke Hirai; Kanji Kuma; Nakaaki Ohsawa

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Ken Yamaguchi

Mitsubishi Chemical Corporation

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