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Dive into the research topics where Kenjiro Nagai is active.

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Featured researches published by Kenjiro Nagai.


Scientific Reports | 2016

Diagnostic test accuracy of loop-mediated isothermal amplification assay for Mycobacterium tuberculosis: systematic review and meta-analysis

Kenjiro Nagai; Nobuyuki Horita; Masaki Yamamoto; Toshinori Tsukahara; Hideyuki Nagakura; Ken Tashiro; Yuji Shibata; Hiroki Watanabe; Kentaro Nakashima; Ryota Ushio; Misako Ikeda; Atsuya Narita; Akinori Kanai; Takashi Sato; Takeshi Kaneko

Diagnostic test accuracy of the loop-mediated isothermal amplification (LAMP) assay for culture proven tuberculosis is unclear. We searched electronic databases for both cohort and case-control studies that provided data to calculate sensitivity and specificity. The index test was any LAMP assay including both commercialized kits and in-house assays. Culture-proven M. tuberculosis was considered a positive reference test. We included 26 studies on 9330 sputum samples and one study on 315 extra-pulmonary specimens. For sputum samples, 26 studies yielded the summary estimates of sensitivity of 89.6% (95% CI 85.6–92.6%), specificity of 94.0% (95% CI 91.0–96.1%), and a diagnostic odds ratio of 145 (95% CI 93–226). Nine studies focusing on Loopamp MTBC yielded the summary estimates of sensitivity of 80.9% (95% CI 76.0–85.1%) and specificity of 96.5% (95% CI 94.7–97.7%). Loopamp MTBC had higher sensitivity and lower specificity for smear-positive sputa compared to smear-negative sputa. In-house assays showed higher sensitivity and lower specificity compared to Loopamp MTBC. LAMP promises to be a useful test for the diagnosis of TB, however there is still need to improve the assay to make it simpler, cheaper and more efficient to make it competitive against other PCR methods already available.


Scientific Reports | 2015

Topotecan for Relapsed Small-cell Lung Cancer: Systematic Review and Meta-Analysis of 1347 Patients

Nobuyuki Horita; Masaki Yamamoto; Takashi Sato; Toshinori Tsukahara; Hideyuki Nagakura; Ken Tashiro; Yuji Shibata; Hiroki Watanabe; Kenjiro Nagai; Miyo Inoue; Kentaro Nakashima; Ryota Ushio; Masaharu Shinkai; Makoto Kudo; Takeshi Kaneko

Topotecan is the most reliable chemotherapy regimen for relapsed small-cell lung carcinoma (SCLC). The efficacy and adverse effects of topotecan as reported by previous studies varied greatly. The inclusion criterion was a prospective study that was able to provide data for 6-month over-all survival (OS) rate, 1-year OS rate, objective responses, and/or adverse effects of single agent topotecan as a second line chemotherapy for SCLC, written in English language as a full article. Any topotecan regimen were allowed. Binary data were meta-analyzed with the random-model generic inverse variance method. We included 14 articles consisted of 1347 patients. Pooled values were estimated as follows. Six-month OS rate: 37% (95% CI: 28–46%). One-year OS rate: 9% (95% CI: 5–13%). Response rate: 5% (95% CI: 1–8%). Six-month OS rate: 57% (95% CI: 50–64%). One-year OS rate: 27% (95% CI: 22–32%). Response rate: 17% (95% CI: 11–23%). Grade III/IV neutropenia 69% (95% CI: 58–80%). Grade III/IV thrombopenia 41% (95% CI: 34–48%). Grade III/IV anemia 24% (95% CI: 17–30%). Non-hematorogical events were rare. Chemotherapy-related death 2% (95% CI: 1–3%). In conclusion, Topotecan provided a possibly promising outcome for sensitive-relapse SCLC and poor outcome for refractory relapse SCLC. Adverse events were mainly hematological.


Scientific Reports | 2016

Diagnostic test accuracy of anti-glycopeptidolipid-core IgA antibodies for Mycobacterium avium complex pulmonary disease: systematic review and meta-analysis.

Yuji Shibata; Nobuyuki Horita; Masaki Yamamoto; Toshinori Tsukahara; Hideyuki Nagakura; Ken Tashiro; Hiroki Watanabe; Kenjiro Nagai; Kentaro Nakashima; Ryota Ushio; Misako Ikeda; Atsuya Narita; Akinori Kanai; Takashi Sato; Takeshi Kaneko

Currently, an anti-glycopeptidolipid (GPL)-core IgA antibody assay kit for diagnosing Mycobacterium avium complex (MAC) is commercially available. We conducted this systematic review and meta-analysis to reveal the precise diagnostic accuracy of anti-GPL-core IgA antibodies for MAC pulmonary disease (MAC-PD). We systematically searched reports that could provide data for both sensitivity and specificity by anti-GPL-core IgA antibody for clinically diagnosed MAC-PD. Diagnostic test accuracy was estimated using the bivariate model. Of the 257 articles that we had found through primary search, we finally included 16 reports consisted of 1098 reference positive subjects and 2270 reference negative subjects. The diagnostic odds ratio was 24.8 (95% CI 11.6–52.8, I2 = 5.5%) and the area under the hierarchical summary receiver operating characteristic curves was 0.873 (95% CI 0.837–0.913). With a cutoff value of 0.7 U/mL, the summary estimates of sensitivity and specificity were 0.696 (95% CI 0.621–0.761) and 0.906 (95% CI 0.836–0.951), respectively. The positive and negative likelihood ratios were 7.4 (95% CI 4.1–13.8) and 0.34 (95% CI 0.26–0.43), respectively. The demanding clinical diagnostic criteria may be a cause of false positive of the index test. The index test had good overall diagnostic accuracy and was useful to ruling in MAC-PD with the cutoff value.


Journal of Thoracic Oncology | 2016

Progression-Free Survival, Response Rate, and Disease Control Rate as Predictors of Overall Survival in Phase III Randomized Controlled Trials Evaluating the First-Line Chemotherapy for Advanced, Locally Advanced, and Recurrent Non–Small Cell Lung Carcinoma

Kentaro Nakashima; Nobuyuki Horita; Kenjiro Nagai; Saki Manabe; Shuji Murakami; Erika Ota; Takeshi Kaneko

Introduction: Recent improvements in chemotherapy agents have prolonged postprogression survival of non–small cell lung cancer. Thus, primary outcomes other than overall survival (OS) have been frequently used for recent phase III trials to obtain quick results. However, no systematic review had assessed whether progression‐free survival (PFS), response rate (RR), and disease control rate (DCR) can serve as surrogates for OS at the trial level in the phase III first‐line chemotherapy setting. Methods: We included phase III randomized clinical trials (RCTs) comparing two arms that were reported as a full article regardless of their primary end point. We included only RCTs that evaluated chemonaive patients with advanced, locally advanced, or metastatic non–small cell lung cancer and were published after January 1, 2005. We systematically searched four public electronic databases. Two investigators independently screened and scrutinized candidate articles. How surrogate outcomes represented hazard ratios (HRs) for OS was examined. Results: Among 1907 articles, we ultimately found 44 eligible articles covering 22,709 subjects. HR for PFS, median PFS in the experimental arm minus median PFS in the control arm in months, OR for RR (ORrr), and OR for DCR were evaluated in 34, 35, 44, and 35 RCTs, respectively. HR for OS (HRos), median PFS in the experimental arm minus median PFS in the control arm, ORrr, and OR for DCR had weighted Spearmans rank correlation coefficients with an HRos of 0.496, 0.477, 0.570, and 0.470, respectively; the standardized weighted regression coefficients were 0.439, –0.376, –0.605, and –0.381, respectively; and the adjusted weighted coefficients of determination were 0.224, 0.161, 0.350, and 0.176, respectively. Conclusions: ORrr, followed by HRpfs, had the strongest association with HRos at the trial level. However, these measures were not strong enough to replace OS.


Scientific Reports | 2016

Sensitivity and specificity of Cobas TaqMan MTB real-time polymerase chain reaction for culture-proven Mycobacterium tuberculosis: meta-analysis of 26999 specimens from 17 Studies

Nobuyuki Horita; Masaki Yamamoto; Takashi Sato; Toshinori Tsukahara; Hideyuki Nagakura; Ken Tashiro; Yuji Shibata; Hiroki Watanabe; Kenjiro Nagai; Kentaro Nakashima; Ryota Ushio; Misako Ikeda; Kentaro Sakamaki; Takashi Yoshiyama; Takeshi Kaneko

Since 2010, studies on the diagnostic accuracy of COBAS TaqMan MTB (CTM) have been frequently reported with an unignorable discrepancy. The key inclusion criterion for this systematic review was original studies that could provide sufficient data for calculating the sensitivity and the specificity of CTM for M tuberculosis (TB) or M tuberculosis complex. The reference test was Mycobacterium culture. We used bivariate model for meta-analyses. Of the 201 candidate articles, we finally identified 17 eligible articles.Concerning the respiratory specimens, 1900 culture positive specimens and 20983 culture negative specimens from 15 studies were assessed. This provided the summary estimate sensitivity of 0.808 (95% CI 0.758–0.850) and the summary estimate specificity of 0.990 (95% CI 0.981–0.994). The area under curve was 0.956. The diagnostic odds ratio was 459 (95% CI 261–805, I2 26%). For the smear positive respiratory specimens, the sensitivity was 0.952 (95% CI 0.926–0.969) and the specificity was 0.916 (95% CI 0.797–0.968). For the smear negative respiratory specimens, the sensitivity and the specificity were 0.600 (95% CI 0.459–0.726) and 0.989 (95% CI 0.981–0.993), respectively. The diagnostic accuracy was poorer for the non-respiratory specimens, than for the respiratory specimens, but was acceptable. We believe that the information obtained from this study will aid physicians’ decision making.


Scientific Reports | 2016

Amrubicin for relapsed small-cell lung cancer: a systematic review and meta-analysis of 803 patients

Nobuyuki Horita; Masaki Yamamoto; Takashi Sato; Toshinori Tsukahara; Hideyuki Nagakura; Ken Tashiro; Yuji Shibata; Hiroki Watanabe; Kenjiro Nagai; Kentaro Nakashima; Ryota Ushio; Misako Ikeda; Nobuaki Kobayashi; Masaharu Shinkai; Makoto Kudo; Takeshi Kaneko

Currently, amrubicin is permitted for relapsed small-cell lung carcinoma (SCLC) only in Japan. The efficacy and adverse effects of amrubicin as reported by previous studies varied greatly. The inclusion criterion was a prospective study that was able to provide data for efficacy and safety by the AMR single agent regimen as second-line chemotherapy for a patient with SCLC. Binary data were meta-analyzed with the random-model generic inverse variance method. We included nine articles consisted of 803 patients. The pooled three-, six-, and nine-month progression-free survival were 63% (95% CI 57–69%, I2 = 53%), 28% (95% CI 21–35%, I2 = 71%), and 10% (95% CI 6–14%, I2 = 41%), respectively. The pooled six-, 12-, and 18-month overall survival were 69% (95% CI 61–78%, I2 = 83%), 36% (95% CI 28–44%, I2 = 80%), and 15% (95% CI 8–21%, I2 = 81%), respectively. Amrubicin seemed much more beneficial for Japanese patients. However, compared to the efficacy of topotecan presented in a previous meta-analysis, amrubicin may be a better treatment option than topotecan for both Japanese and Euro-American. Adverse effects by amrubicin were almost exclusively observed to be hematological. Notably, grade III/IV neutropenia incidence was 70% and febrile neutropenia incidence was 12%.


Scientific Reports | 2016

Age, Dehydration, Respiratory Failure, Orientation Disturbance, and Blood Pressure Score Predicts In-hospital Mortality in HIV-negative Non-multidrug-resistant Smear-positive Pulmonary Tuberculosis in Japan

Kenjiro Nagai; Nobuyuki Horita; Takashi Sato; Masaki Yamamoto; Hideyuki Nagakura; Takeshi Kaneko

The A-DROP scoring system was originally designed to assess clinical severity of community acquired pneumonia using the following parameters: advanced Age, Dehydration, Respiratory failure, Orientation disturbance (confusion); and, low blood Pressure. Total A-DROP score ranges zero to five assigning one point for each component, wherein five indicates the poorest prognosis. The purpose of this single-center retrospective study was to determine whether A-DROP could predict the risk for death in patients with pulmonary tuberculosis. We reviewed consecutive HIV-negative, non-multidrug-resistant smear-positive adult pulmonary tuberculosis patients. The cohort consisted of 134 men (38.8%), 211 women (61.2%), 272 who discharged alive (28.8%), and 73 who died in-hospital (21.2%) with a median age of 72 (IQR: 54–82) years. A one-point increase in the A-DROP score was associated with a higher risk for in-hospital mortality with odds ratio of 3.8 (95% confidence interval 2.8–5.2, P < 0.001). The area under receiver operating characteristics curve was 0.86. The total score cutoff of 1.5 provided the best Youden Index of 0.61. Using this criteria, total score >1.5, sensitivity was 85% and specificity was 76%. Kaplan-Meier curve clearly indicated that in-hospital mortality increased with higher A-DROP scores (Log-rank test <0.001). In conclusion, A-DROP score clearly indicate pulmonary tuberculosis in-hospital mortality.


Internal Medicine | 2018

The Platelet Count can Predict In-hospital Death in HIV-negative Smear-positive Pulmonary Tuberculosis Inpatients

Hideto Goto; Nobuyuki Horita; Ken Tashiro; Kenjiro Nagai; Masaki Yamamoto; Takashi Sato; Yu Hara; Hideyuki Nagakura; Yuji Shibata; Hiroki Watanabe; Kentaro Nakashima; Ryota Ushio; Akimichi Nagashima; Misako Ikeda; Atsuya Narita; Katsuhito Sasaki; Nobuaki Kobayashi; Makoto Kudo; Takeshi Kaneko

Objective This retrospective cohort study investigated whether the three components of the blood cell count have prognostic implications in HIV-negative Japanese adult inpatients with smear-positive pulmonary tuberculosis. Methods We reviewed patients who were treated by the isoniazid, rifampicin, pyrazinamide, and ethambutol regimen or by the isoniazid, rifampicin, and ethambutol regimen. The association between the patient data on admission and the survival outcome was evaluated. Results We reviewed 367 consecutive patients (male, 60.5%) with a median age of 72 [interquartile range (IQR), 54-82] years. While the white blood cell count did not differ between the two groups, (discharged alive: 7,000/μL; IQR, 5,500-9,300; died in hospital: 7,200/μL; IQR, 5,600-9,400; p=0.797), hemoglobin level (discharged alive: 11.5 g/dL; IQR, 10.0-13.1; died in hospital: 9.9 g/dL; IQR, 8.6-11.3; p<0.001) and the platelet count (discharged alive: 275,000/μL; IQR, 206,000-345,000; died in hospital: 149,000/μL; IQR, 93,000-236,000; p<0.001) were lower in patients who died in hospital. After dividing patients into hemoglobin- and platelet-based quantiles, the lower quantile class tended to show poorer survival (log-rank test for trend p<0.001 for both). A multi-variable Cox proportional hazards model revealed that hazard ratio for in-hospital death for every 1,000/μL increase of platelet count was 0.997 (95%CI, 0.995-0.999; p=0.010); the hazard ratio for the hemoglobin level was not significant. Conclusion A low platelet count was clearly related to a poor life prognosis in HIV-negative Japanese adult inpatients with smear-positive pulmonary tuberculosis.


Clinical Respiratory Journal | 2018

Modification of oxygen concentrators based on questionnaire survey

Masahiro Shinoda; Masaharu Shinkai; Akimichi Nagashima; Kenjiro Nagai; Kei Takagi; Takeshi Kaneko

In this study, we conducted a questionnaire survey to clarify and improve problems related to oxygen concentrators.


Canadian Respiratory Journal | 2018

ELISA Development for Serum Hemeoxygenase-1 and Its Application to Patients with Acute Respiratory Distress Syndrome

Yu Hara; Masaharu Shinkai; Masataka Taguri; Kenjiro Nagai; Satoru Hashimoto; Takeshi Kaneko

Background Hemeoxygenase-1 (HO-1) is an essential enzyme in heme catabolism and has been proposed as a biomarker of lung disease prognosis. We modified a commercial HO-1 enzyme-linked immunosorbent assay (ELISA) kit to achieve higher sensitivity and evaluated if serum HO-1 could be a biomarker to predict the prognosis of acute respiratory distress syndrome (ARDS) patients. Methods Serum samples were collected from 15 healthy volunteers to validate the modified ELISA. In the 22 patients with ARDS who were enrolled, serum HO-1 was measured upon diagnosis (D0) and at 7 days after diagnosis (D7). Results The serum HO-1 concentration could be measured in all healthy volunteers. The intra- and interassay tests and the percentage recovery test were acceptable. Compared with normal control subjects, patients with ARDS had significantly higher D0 HO-1 concentrations (75.4 ng/mL versus 31.7 ng/mL, P < 0.001). The 28-day survival was significantly better in patients with low D0 HO-1 (<75.8 ng/mL) than in those with high D0 HO-1 (≥75.8 ng/mL) (mortality rate: 18% versus 73%, P=0.016). Nonsurvivors had significantly higher D0 and D7 HO-1 concentrations than survivors (P < 0.05). Conclusion Serum HO-1 may be a useful biomarker to predict the prognosis of patients with ARDS.

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Takeshi Kaneko

Yokohama City University

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Takashi Sato

Yokohama City University

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Yuji Shibata

Yokohama City University

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Ken Tashiro

Yokohama City University

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Ryota Ushio

Yokohama City University

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