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Dive into the research topics where Masao Nakata is active.

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Featured researches published by Masao Nakata.


The Annals of Thoracic Surgery | 2000

Pulmonary Function After Lobectomy: Video- Assisted Thoracic Surgery Versus Thoracotomy

Masao Nakata; Hideyuki Saeki; Nobuji Yokoyama; Akira Kurita; Wataru Takiyama; Shigemitsu Takashima

BACKGROUND Whether video-assisted thoracic surgery (VATS) improves postoperative pulmonary function is still controversial. We compared postoperative pulmonary function after VATS lobectomy and standard lobectomy. METHODS Eleven patients who had undergone standard lobectomy and 10 patients who had undergone VATS lobectomy were studied. Arterial blood gas analyses were performed on the 4th, 7th, and 14th postoperative days. Pulmonary function, including forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1.0), and peak flow rate (PFR) were measured on the 7th and 14th postoperative days (early phase), and approximately 1 year after surgery (late phase). RESULTS Pulmonary function, as assessed with arterial oxygen partial pressure (PaO2) (p = 0.054), arterial oxygen saturation (O2SAT) (p = 0.063), FVC (p = 0.10), and FEV1.0 (p = 0.08), was better after VATS lobectomy than after thoracotomy on the 7th postoperative day. PFR was significantly better after VATS on both the 7th and 14th postoperative days (p = 0.008 and p = 0.03, respectively). CONCLUSIONS VATS lobectomy had advantages on early postoperative pulmonary function. We conclude that VATS lobectomy is a beneficial alternative to standard thoracotomy, especially for patients with poor pulmonary reserve.


The Annals of Thoracic Surgery | 2003

Prospective study of thoracoscopic limited resection for ground-glass opacity selected by computed tomography

Masao Nakata; Shigeki Sawada; Hideyuki Saeki; Shigemitsu Takashima; Hiroshi Mogami; Norihiro Teramoto; Kenji Eguchi

BACKGROUND With recent advances in low-dose helical computed tomography (CT), detection of ground-glass opacity (GGO) has increased. The aim of this study was to correlate high-resolution CT (HRCT) findings with pathologic features and to evaluate the efficacy of thoracoscopic limited resection for focal GGO, which were selected based on HRCT findings. METHODS Focal GGO lesions were classified into two subtypes based on HRCT findings: pure type and mixed type. Ninety-six patients with persistent GGO 2 cm or less in diameter underwent pulmonary resection from January 1997 to December 2001. Among these, thoracoscopic wedge resection was performed prospectively between June 2000 and December 2001 in 33 patients with pure GGO lesions that were 1 cm or less. RESULTS Thoracoscopic wedge resection was completed with complete safety. The histologic diagnoses of these 33 lesions were adenocarcinoma in 1, bronchioloalveolar carcinoma (BAC) in 23, and atypical adenomatous hyperplasia (AAH) in 9. No patients have had any evidence of tumor recurrence to date. Of the total 96 GGO lesions, 93.0% (53/57) of pure GGO 1 cm or less were BAC or AAH, whereas 38.5% (15/39) of pure GGO larger than 1 cm or mixed GGO were adenocarcinoma. CONCLUSIONS Pure GGO 1 cm or less was characteristic of noninvasive lesions. Thoracoscopic limited resection for small GGO lesions selected by HRCT was valid.


Lung Cancer | 1999

Clinical investigation of atypical adenomatous hyperplasia of the lung

Nagio Takigawa; Yoshihiko Segawa; Masao Nakata; Hideyuki Saeki; Koichi Mandai; Daizo Kishino; Michihide Shimono; Mikiko Ida; Kenji Eguchi

The clinicopathologic characteristics of atypical adenomatous hyperplasia (AAH) remain unclear. A total of 137 patients underwent resection for adenocarcinoma of the lung at our institution. Examination of resected lung tissue showed that in addition to adenocarcinoma AAH was present in 26 cases and was not present in 111 cases. All nonsmokers with AAH (n = 13) had earlier-stage disease (stage IA, IB, IIA, and IIB) and no history of respiratory disease. Among patients with stage IA disease, the relapse-free and overall survival curves for those with AAH (n = 14) tended to be better than for those without AAH (n = 40), but the difference was not statistically significant (P = 0.056 and 0.087, respectively). Concurrent presence of AAH may be a favorable prognostic indicator in patients with stage IA adenocarcinoma.


The Journal of Thoracic and Cardiovascular Surgery | 2008

Teratoma with malignant transformation in the anterior mediastinum

Katsuhiko Shimizu; Masao Nakata; Yuji Hirami; Takashi Akiyama; Kazuo Tanemoto

References 1. Oey IF, Jeyapalan K, Entwisle JJ, Waller DA. Pseudo-tumours of the lung after lung volume reduction surgery. Ann Thorac Surg. 2004;77: 1094-6. 2. Dumon JF, Cavaliere S, Diaz-Jimenez JP, et al. Seven year experience with the Dumon prosthesis. J Bronchol. 1996;3:6-10. 3. Hocwald E, Sichel JY, Dano I, Meir K, Eliashar R. Adverse reaction to surgical sutures in thyroid surgery. Head Neck. 2003;25: 77-81. 4. Baughman RP, Lower EE, du Bois RM. Sarcoidosis. Lancet. 2003;361: 1111-8. 5. MacEwen C, Gregson R. Complications of strabismus surgery: how to avoid and manage them. In: Manual of strabismus surgery. Oxford: Butterworth-Heinemann; 2003. p. 181. Figure 2. Granulation tissue seen over the distal end of the Y-stent at the left bronchial arm 1 week after placement (A) and 3 months after the commencement of steroid treatment (B). Brief Communications


Lung Cancer | 1998

Two cases of intrapulmonary lymph node presenting as a peripheral nodular shadow: Diagnostic differentiation from lung cancer

Nobukazu Fujimoto; Yoshihiko Segewa; Nagio Takigawa; Ichiro Takata; Katsuyuki Hotta; Hiroshi Mogami; Masao Nakata; Koichi Mandai; Kenji Eguchi

We present two cases of intrapulmonary lymph node. The patients were a 44-year-old woman and a 71-year-old man each with a small peripheral nodule in the lung. On computed tomography (CT) scans, both nodules were spiculated. Since histological diagnosis could not be obtained by bronchoscopic examination or CT-guided needle biopsy, they underwent video-assisted thoracoscopic surgery. Histological examination of the resected material revealed that both nodules were composed of lymph node. Intrapulmonary lymph node has until recently been assigned no clinical significance; however, differential diagnosis of this lesion from lung cancers and other metastatic tumors is now clinically important.


Therapeutics and Clinical Risk Management | 2015

Prognostic nutritional index before adjuvant chemotherapy predicts chemotherapy compliance and survival among patients with non-small-cell lung cancer

Katsuhiko Shimizu; Riki Okita; Shinsuke Saisho; Takuro Yukawa; Ai Maeda; Yuji Nojima; Masao Nakata

Background Adjuvant chemotherapy after the complete resection of non-small-cell lung cancer (NSCLC) is now the standard of care. To improve survival, it is important to identify risk factors for the continuation of adjuvant chemotherapy. In this study, we analyzed chemotherapy compliance and magnitude of the prognostic impact of the prognostic nutritional index (PNI) before adjuvant chemotherapy. Methods We conducted a retrospective review of data from 106 patients who had received adjuvant chemotherapy. The adjuvant chemotherapy consisted of an oral tegafur agent (OT) or platinum-based chemotherapy (PB). The correlations between the PNI values and recurrence-free survival (RFS) were then evaluated. Results In the PB group, the percentage of patients who completed the four planned cycles of chemotherapy was not correlated with the PNI. In the OT group, however, a significant difference was observed in the percentage of patients who completed the planned chemotherapy according to the PNI before adjuvant chemotherapy. The RFS of patients with a PNI <50 before adjuvant chemotherapy was significantly poorer than that of the patients with a PNI ≥50. A multivariate analysis showed that nodal metastasis and PNI before chemotherapy were independent predictors of the RFS. However, PNI before surgery was not a predictor of the RFS. In the subgroup analysis, PNI before chemotherapy was independent predictor of the RFS in the OT group (P=0.019), but not in the PB group (P=0.095). Conclusion The PNI before adjuvant chemotherapy influenced the treatment compliance with the planned chemotherapy in the OT group, but not the PB group. In addition, a low PNI before adjuvant chemotherapy was associated with a poor RFS in a multivariate analysis, especially in the OT group.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 2002

Unsuspected primary pulmonary malignant lymphoma

Hiroyuki Tao; Masao Nakata; Hideyuki Saeki; Akira Kurita; Shigemitsu Takashima

A 70-year-old man referred for treatment of a left lower lung tumor was shown in chest computed tomography to have a homogeneous round tumor 45 mm in diameter with an enhanced thin wall in the lower lobe of the left lung. No specific finding was seen in material obtained by transbronchial and computed tomography (CT)-guided lung tissue biopsy, so the presumptive diagnosis was a lung abscess. Despite antibiotics administered for 2 weeks, radiography showed the tumor had grown, necessitating left lower lobectomy. The permanent section was diagnosed as diffuse large B-cell lymphoma. Because CT findings for the tumor suggested a lung abscess and the central part of the tumor consisted of fibrotic and necrotic tissue, we had difficulty establishing a final diagnosis. The literature showed primary pulmonary lymphomas yielded a variety of findings radiographically, making surgery paramount for ascertaining a final diagnosis.


OncoTargets and Therapy | 2016

Clinicopathological and immunohistochemical features of lung invasive mucinous adenocarcinoma based on computed tomography findings

Katsuhiko Shimizu; Riki Okita; Shinsuke Saisho; Ai Maeda; Yuji Nojima; Masao Nakata

Background We performed an analysis to clarify differences in clinicopathological and molecular features of lung invasive mucinous adenocarcinoma (IMA) based on computed tomography (CT) findings and their impact on prognosis. Patients and methods On the basis of CT findings, we divided lung IMA into three subtypes: solid, bubbling, and pneumonic. We then investigated differences in clinicopathological characteristics, prognosis, and the expressions of well-identified biomarkers, including cyclooxygenase-2 (Cox-2), excision repair cross-complementation group 1 (ERCC1), ribonucleotide reductase M1 (RRM1), class III beta-tubulin, thymidylate synthase (TS), secreted protein acidic and rich in cysteine (SPARC), programmed cell death-1 ligand-1 (PD-L1), and epidermal growth factor receptor mutation, among the three subtypes. Results A total of 29 patients with resected lung IMA were analyzed. Compared with the solid or bubbling type, the pneumonic type had a higher proportion of symptoms, a larger tumor size, a higher pathological stage, and a significantly worse prognosis. The immunohistochemical findings tended to show high expression of RRM1, class III beta-tubulin, and Cox-2 in the tumor and of SPARC in the stroma, but not of ERCC1, TS, and PD-L1 in the tumor. None of the biomarkers with high expression levels in the tumor were prognostic biomarkers, but the expression of SPARC in the stroma was correlated with a poor outcome. Conclusion Clinical and pathological features, in conjunction with molecular data, indicate that IMA should be divided into different subgroups. In our results, the pneumonic type was correlated with a significantly worse outcome. Further studies should be performed to confirm our conclusion and to explore its molecular implications.


Journal of Thoracic Disease | 2018

Epithelial-mesenchymal transition-induced metastasis could be a bait for natural killer cells

Riki Okita; Katsuhiko Shimizu; Masao Nakata

Recent research has shown that several mechanisms induce tumor progression and a novel cause is the escape of tumor cells from immune surveillance (1). Natural killer (NK) cells play an important role in immunosurveillance against cancer cells (2), and the immunosurveillance by NK cells involves NK cell-mediated tumor cytotoxicity, which depends on the balance between NK cell-activating and -inhibiting ligands expressed in tumor cells (3).


Anticancer Research | 2018

Impact of COX2 Inhibitor for Regulation of PD-L1 Expression in Non-small Cell Lung Cancer

Katsuhiko Shimizu; Riki Okita; Shinsuke Saisho; Ai Maeda; Yuji Nojima; Masao Nakata

Background/Aim: There is no clear evidence in the literature regarding the regulation of programmed cell death-ligand 1 (PD-L1) expression by cyclo-oxygenase-2 (COX2). In this study, whether PD-L1 expression was regulated by COX2 activity was examined in vitro. Materials and Methods: Resected lung cancer specimens were analyzed for PD-L1 and COX2 expression by immunohistochemical analysis. Next, co-localization of PD-L1 and COX2 expression was analyzed by double-fluorescence staining. Lastly, the effect of COX2 inhibition on the expression of PD-L1 was examined using lung cancer cell lines. Results: PD-L1 expression was significantly correlated with COX2 expression in the resected specimens. The majority of cancer cells that expressed PD-L1 also co-expressed COX2. However, treatment of lung cancer cell lines with a COX2 inhibitor had no impact on PD-L1 expression. Conclusion: Our results suggest that COX2 inhibition might have no effect on the usage of immune checkpoint inhibitors in lung cancer treatment.

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Hideyuki Saeki

Saitama Medical University

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Ai Maeda

Kawasaki Medical School

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Yuji Hirami

Kawasaki Medical School

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