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Dive into the research topics where Kimito Osaka is active.

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Featured researches published by Kimito Osaka.


BMC Cancer | 2016

Neutrophil-to-lymphocyte ratio is a prognostic marker in bladder cancer patients after radical cystectomy

Takashi Kawahara; Kazuhiro Furuya; Manami Nakamura; Kentaro Sakamaki; Kimito Osaka; Hiroki Ito; Yusuke Ito; Koji Izumi; Shinji Ohtake; Yasuhide Miyoshi; Kazuhide Makiyama; Noboru Nakaigawa; Takeharu Yamanaka; Hiroshi Miyamoto; Masahiro Yao; Hiroji Uemura

BackgroundThere is no reliable biomarker for predicting the prognosis of patients who undergo radical cystectomy for bladder cancer. Recent studies have shown that the neutrophil-to-lymphocyte ratio (NLR) could function as a useful prognostic factor in several types of malignancies. This study aimed to assess the usefulness of NLR in bladder cancer.MethodsA total of 74 patients who underwent radical cystectomy in our institutions from 1999 to 2014 were analyzed. The NLR was calculated using the patients’ neutrophil and lymphocyte counts before radical cystectomy. An immunohistochemical analysis was also performed to detect tumor infiltrating neutrophils (CD66b) and lymphocytes (CD8) in bladder cancer specimens.ResultsA univariate analysis showed that the patients with a high NLR (≥2.38; HR = 4.84; p = 0.007), high C-reactive protein level (>0.08; HR = 10.06; p = 0.030), or pathological lymph node metastasis (HR = 4.73; p = 0.030) had a significantly higher risk of cancer-specific mortality. Kaplan-Meier and log-rank tests further revealed that NLR was strongly correlated with overall survival (p = 0.018), but not progression-free survival (p = 0.137). In a multivariate analysis, all of these were found to be independent risk factors (HR = 4.62, 10.8, and 12.35, respectively). The number of CD8-positive lymphocytes was significantly increased in high-grade (p = 0.001) and muscle-invasive (p = 0.012) tumors, in comparison to low-grade and non-muscle-invasive tumors, respectively.ConclusionsThe NLR predicted the prognosis of patients who underwent radical cystectomy and might therefore function as a reliable biomarker in cases of invasive bladder cancer.


International Journal of Urology | 2015

Predictors of trifecta outcomes in laparoscopic partial nephrectomy for clinical T1a renal masses

Kimito Osaka; Kazuhide Makiyama; Noboru Nakaigawa; Masahiro Yao

To assess trifecta outcomes for laparoscopic partial nephrectomy for clinical T1a renal masses.


Advances in Urology | 2015

Measurement of the Physical Properties during Laparoscopic Surgery Performed on Pigs by Using Forceps with Pressure Sensors

Hiroyuki Yamanaka; Kazuhide Makiyama; Kimito Osaka; Manabu Nagasaka; Masato Ogata; Takahiro Yamada; Yoshinobu Kubota

Objectives. Here we developed a unique training system, a patient specific virtual reality simulator, for laparoscopic renal surgery. To develop the simulator, it was important to first identify the physical properties of the organ. Methods. We recorded the force measured during laparoscopic surgery performed on pigs by using forceps with pressure sensors. Several sensors, including strain gauges, accelerometers, and a potentiometer, are attached to the forceps. Results. Throughout the experiment, we measured the reaction force in response to the forceps movement in real time. Conclusions. The experiment showed the possibility of digitizing these physical properties in humans as well.


Scandinavian Journal of Urology and Nephrology | 2017

Measurement of serum isoform [–2]proPSA derivatives shows superior accuracy to magnetic resonance imaging in the diagnosis of prostate cancer in patients with a total prostate-specific antigen level of 2–10 ng/ml

Kazuhiro Furuya; Takashi Kawahara; Masaki Narahara; Takashi Tokita; Sachi Fukui; Masashi Imano; Taku Mitome; Yusuke Ito; Koji Izumi; Kimito Osaka; Yumiko Yokomizo; Narihiko Hayashi; Hisashi Hasumi; Shintaro Nawata; Tsuyoshi Kawano; Masahiro Yao; Hiroji Uemura

Abstract Objective: More accurate diagnostic procedures for prostate cancer are needed to avoid unnecessary biopsy due to the low specificity of prostate-specific antigen (PSA). Recent studies showed that the percentage of serum isoform [–2]proPSA (p2PSA) to free PSA (%p2PSA), the Prostate Health Index (PHI) and magnetic resonance imaging (MRI) were more accurate than PSA. The aim of this study was to test the accuracy of %p2PSA, PHI and MRI in discriminating patients with and without prostate cancer. Materials and methods: The subjects were 50 consecutive men with a PSA level of 2.0–10.0 ng/ml, who underwent prostate biopsy from October 2012 to July 2014. These patients underwent multiparametric MRI before biopsy, and their serum samples were measured for PSA, free PSA and p2PSA. The sensitivity, specificity and accuracy of PHI, %p2PSA and MRI were compared with PSA in the diagnosis of biopsy-confirmed prostate cancer. Results: In a univariate analysis, %p2PSA [area under the curve (AUC): 0.811] and PHI (AUC 0.795) were more accurate than MRI (AUC: 0.583) and PSA (AUC: 0.554) for prostate cancer detection. At 60% sensitivity, the specificity of PHI (76.5%) was higher than that of MRI (52.9%). For significant cancer detection, %p2PSA (AUC: 0.745), PHI (AUC: 0.791) and MRI (AUC: 0.739) were marginally more accurate than PSA (AUC: 0.696). At 85% sensitivity, the specificity of MRI (62.1%) was higher than that of PHI (34.5%). Conclusion: PHI and %p2PSA can be used for screening the general population and MRI can be used for detection of significant cancer in patients suspected, from screening tests, of having prostate cancer.


Cuaj-canadian Urological Association Journal | 2015

Successful neoadjuvant chemotherapy for primary invasive small-cell carcinoma of the ureter.

Kimito Osaka; Kazuki Kobayashi; Naoki Sakai; Noguchi S

We report a case of invasive small-cell carcinoma (SCC) of the ureter successfully treated by neoadjuvant chemotherapy and laparoscopic nephroureterectomy. SCC of the ureter is an extremely rare condition characterized by aggressive behaviour. A 70-year-old male presented with left flank pain; he was diagnosed with SCC of the ureter, cT3N0M0, by ureteroscopic biopsy. The patient received 3 cycles of neoadjuvant chemotherapy with cisplatin and irinotecan (IP) and underwent laparoscopic nephroureterectomy. The pathological diagnosis was urothelial carcinoma, high grade, without a small-cell component. The pathological stage was down-staged to pT2N0M0. Adjuvant chemotherapy was not performed. The patient has been free of local recurrence or distant metastasis for 38 months postoperatively. This is the first reported case of primary invasive SCC of the upper urinary tract treated by neoadjuvant chemotherapy followed by nephroureterectomy.


Cancer Chemotherapy and Pharmacology | 2017

One-month assessment of renal cell carcinoma treated by everolimus using FDG PET/CT predicts progression-free and overall survival

Hiroki Ito; Keiichi Kondo; Takashi Kawahara; Tomohiro Kaneta; Ukihide Tateishi; Daiki Ueno; Kazuhiro Namura; Kazuki Kobayashi; Yasuhide Miyoshi; Yasushi Yumura; Kazuhide Makiyama; Narihiko Hayashi; Hisashi Hasumi; Kimito Osaka; Yumiko Yokomizo; Jun-ichi Teranishi; Yusuke Hattori; Tomio Inoue; Hiroji Uemura; Masahiro Yao; Noboru Nakaigawa

PurposeWe evaluated 18F-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) results as outcome predictors for patients with metastatic renal cell carcinoma (RCC) treated by everolimus (EVL), an inhibitor of mammalian target of rapamycin.MethodsWe retrospectively reviewed 30 patients who were treated with EVL for metastatic RCC between May 2010 and March 2015, by evaluating their FDG PET/CT result before and 1 month after starting EVL treatment. We examined the relationships between each patient’s maximum standardized uptake value (max SUVmax) assessed by FDG PET/CT on progression-free survival (PFS) and overall survival (OS).ResultsMedian PFS for all 30 patients was 3.77 months (range 0.72–24.56 months) and median OS after EVL treatment of all 30 patients was 11.67 months (range 1.0–62.98 months). Enrolled patients were divided into two groups by max SUVmax prior to EVL (median = 7.6) and at 1 month after EVL treatment (median = 5.7). PFS were significantly shorter in higher max SUVmax prior to EVL (<7.6, PFS 7.8 vs 3.5 months, log-rank P = 0.017) and at 1 month after EVL (<5.7, PFS 10.6 vs 2.7 months, log-rank P = 0.002) than lower max SUVmax. OS were also significantly shorter in higher max SUVmax prior to EVL (<7.6, OS 18.1 vs 7.5 months, log-rank P = 0.010) and at 1 month after EVL (<5.7, OS 17.2 vs 7.5 months, log-rank P = 0.009) than lower max SUVmax. Multivariate Cox hazard regression analysis indicated that max SUVmax at 1 month after EVL is an independent predictor of both PFS and OS in patients treated with EVL although univariate regression analysis showed max SUVmax before EVL is a possible predictor.ConclusionsMax SUVmax assessed by FDG PET/CT prior to EVL and at 1 month after EVL treatment can accurately predict PFS and can guide decisions on whether to continue or change treatments for patients with EVL-treated RCC who suffer from adverse events.


BioMed Research International | 2016

Pretreatment Neutrophil-to-Lymphocyte Ratio Can Predict the Prognosis in Bladder Cancer Patients Who Receive Gemcitabine and Nedaplatin Therapy

Shinji Ohtake; Takashi Kawahara; Ryo Kasahara; Hiroki Ito; Kimito Osaka; Yusuke Hattori; Jun-ichi Teranishi; Kazuhide Makiyama; Nobuhiko Mizuno; Susumu Umemoto; Yasuhide Miyoshi; Noboru Nakaigawa; Hiroshi Miyamoto; Masahiro Yao; Hiroji Uemura

Introduction and Objectives. Neutrophil-to-lymphocyte ratio (NLR) has been suggested to be a simple marker of the systemic inflammatory response in critical care patients. We previously assessed the utility of NLR as a biomarker to predict tumor recurrence and cancer death in bladder cancer patients who underwent radical cystectomy. In this study, we evaluated the prognostic impact of NLR in bladder cancer patients who received gemcitabine and nedaplatin (GN) chemotherapy. Methods. A total of 23 patients who received GN chemotherapy for advanced bladder cancer were enrolled in this study. The cut-off point of NLR according to the sensitivity and specificity levels was derived from the area under receiver operator characteristics (AUROC) curve plotted for disease progression or overall mortality. Results. The NLR cut-off point was determined as 4.14 for both tumor progression and overall mortality. Median progression-free survival (PFS)/overall survival (OS) in the higher NLR group (NLR ≥ 4.14) and lower NLR group (NLR < 4.14) were 194/468 days versus 73/237 days, respectively. Kaplan-Meier analysis showed that higher NLR significantly correlated with poorer PFS (p = 0.011) and OS (p = 0.045). Conclusions. NLR may serve as a new biomarker to predict responses to GN-based chemotherapy in advanced bladder cancer patients and/or their prognosis.


Journal of Medical Case Reports | 2017

Large cell neuroendocrine carcinoma of the kidney with cardiac metastasis: a case report

Moeka Shimbori; Kimito Osaka; Takashi Kawahara; Ryo Kasahara; Sayuki Kawabata; Kazuhide Makiyama; Keiichi Kondo; Noboru Nakaigawa; Shoji Yamanaka; Masahiro Yao

BackgroundPrimary large cell neuroendocrine carcinoma of the kidney is a rare and generally very aggressive disease. We present a case of a patient with primary large cell neuroendocrine carcinoma of the kidney with cardiac metastasis.Case presentationA 59-year-old Japanese man presented to his previous physician with hematuria. Computed tomography revealed masses in the heart and right kidney, and fluorodeoxyglucose-positron emission tomography showed abnormal uptake in the heart. A cardiac biopsy under transesophageal echocardiographic guidance revealed a metastatic tumor. Subsequently, multiple lung lesions were detected, and a right nephrectomy was performed after these metastases were suspected to have originated from renal carcinoma. Large cell neuroendocrine carcinoma of the kidney was ultimately diagnosed. Pancreatic metastasis was detected on computed tomography postoperatively. Three courses of chemotherapy with carboplatin and irinotecan were administered, and were temporarily effective against the metastatic lesions in the lungs and pancreas. However, our patient’s general condition deteriorated with the progression of the lesions, and he died 9 months after his initial examination.ConclusionsMulti-agent chemotherapy, including platinum-based drugs was effective against large cell neuroendocrine carcinoma metastases, albeit only temporarily. This is the first reported case of large cell neuroendocrine carcinoma with cardiac metastasis.


Clinical Case Reports | 2016

Bilateral renal lymphoma: rapid recovery from an acute kidney injury after open renal biopsy

Taku Mitome; Kazuhiro Furuya; Masashi Imano; Kimito Osaka; Yumiko Yokomizo; Narihiko Hayashi; Noboru Nakaigawa; Shoji Yamanaka; Masahiro Yao

Renal lymphoma as an initial lesion is relatively rare. Bilateral renal lymphoma frequently presents as acute kidney injury. With systematic chemotherapy for the lymphoma, patients usually recover their kidney function. However, in the case we describe here, the patients kidney function recovered greatly after an open renal biopsy. Here, we review and discuss this unique case.


Case reports in urology | 2013

Laparoscopic Nephroureterectomy for Adult Patient with Primary Obstructive Megaureter

Kimito Osaka; Kazuhide Makiyama; Shinji Ohtake; Hiroyuki Yamanaka; Futoshi Sano; Noboru Nakaigawa; Yoshinobu Kubota

A 29-year-old female with a complaint of abdominal distension was referred to our hospital. She had a history of being treated for pyelonephritis three times. By computed tomography and retrograde pyelography, she was diagnosed with adult left primary megaureter. Her left renal function was severely deteriorated. She hoped for surgical intervention before becoming pregnant. Laparoscopic nephroureterectomy for megaureters seems to be difficult due to the large size. By sucking urine from an inserted ureteral catheter and setting trocar positions, we successfully performed laparoscopic nephroureterectomy for megaureter.

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Masahiro Yao

Yokohama City University

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Takashi Kawahara

Yokohama City University Medical Center

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Yusuke Ito

Yokohama City University

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Koji Izumi

Yokohama City University

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Naoki Sakai

Yokohama City University

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Noguchi S

Yokohama City University

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