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Dive into the research topics where Takehiko Okamura is active.

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Featured researches published by Takehiko Okamura.


Cancer | 1984

Effects of lntravesical instillation of antitumor chemotherapeutic agents on bladder carcinogenesis in rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine

Mikinobu Ohtani; Shojl Fukushima; Takehiko Okamura; Takao Sakata; Nobuyuki Ito; Kenkichl Koiso; Tadao Niijima

The effects of intravesical instillation of Adriamycin (doxorubicin) (ADR), and mitomycin C (MMC), as inhibitors of development of rat bladder tumors, were examined in rats treated with N‐butyl‐N‐(4‐hydroxybuty1)nitrosamine (BBN). Intravesical instillation of ADR or MMC once a week for 12 weeks into rats pretreated with BBN for 4 weeks markedly enhanced development of bladder tumors. That is, one week after the end of intravesical instillation of these compounds the incidence of papillary or nodular hyperplasias, namely preneoplastic lesions, was significantly increased, and at the end of the experiment the incidence of not only papillary or nodular hyperplasias but also of papillomas and cancers was significantly increased. These results indicate that the intravesical instillation of ADR or MMC promotes two‐stage bladder carcinogenesis in rats.


Urologia Internationalis | 1999

Osteopontin Expression in Prostate Cancer and Benign Prostatic Hyperplasia

Keiichi Tozawa; Yasuyuki Yamada; Noriyasu Kawai; Takehiko Okamura; Kosuke Ueda; Kenjiro Kohri

Objectives: Osteopontin (OPN), a secreted adhesive glycoprotein, has been shown to be produced in excessive amounts in a variety of experimental models of malignancy. Increased levels of OPN exist in blood from the lungs, breasts, and gastrointestinal tracts of cancer patients with metastases. However, there have been no reports on the expression of OPN in human urological malignancies. The present study investigates the presence of OPN in adenocarcinoma of the human prostate and in benign prostatic hyperplasia (BPH). Patients and Methods: Using prostate tissue from 34 patients with primary prostate cancer, 13 patients with prostate cancer after having undergone hormonal therapy, and 12 patients with BPH, formalin-fixed paraffin sections were prepared. Specimens were obtained by needle biopsy or radical prostatectomy. Immunohistochemical staining (ABC method) was then performed. Staining was divided into either negative or positive categories. Results: Positive staining of OPN was observed on cancer cells and macrophages in 52.9% of the primary prostate cancers and 14.5% of the prostate cancers after hormonal therapy. In BPH specimens, 66.7% of the cases displayed positive staining of OPN. The staining level of OPN showed no correlation with serum prostate-specific antigen, but did correlate with stage, differentiation, and Gleason’s score. Conclusions: The result postulates that the expression of OPN is an indicator of cell differentiation; however, it cannot be used as a marker of malignance in prostate cancer.


The Journal of Urology | 1996

Clinicopathological Evaluation of Repeated Courses of Intravesical Bacillus Calmette-Guerin Instillation for Preventing Recurrence of Initially Resistant Superficial Bladder Cancer

Takehiko Okamura; Keiichi Tozawa; Yasuyuki Yamada; Hiroshi Sakagami; Kousuke Ueda; Kenjiro Kohri

PURPOSEnThe efficacy of repeated courses of intravesical bacillus Calmette-Guerin (BCG) for superficial bladder cancer was assessed with particular attention to initially resistant cases.nnnMATERIALS AND METHODSnA total of 75 patients with stages Ta to T1b superficial transitional cell bladder carcinoma received 6 weekly instillations of 80 mg. Tokyo strain BCG in 40 ml. saline followed by 6 instillations at monthly intervals. If tumors recurred, another course of treatment was given with surgery.nnnRESULTSnOf 17 patients (22.7%) with recurrent tumor at followup periods of up to 84 months 12 received an additional course of BCG instillations according to the same protocol after transurethral resection of bladder tumors, and 10 (83.3%) showed no further recurrence with or without additional surgery and BCG therapy after a median followup of 42.9 months. Thus, the overall success rate with this approach was 90.7% (68 of 75 patients). Comparison of patients with and without recurrence revealed a significant difference in number of tumors before therapy (p < 0.05), and a pronounced tendency (p = 0.00507) for recurrence after prior systemic chemotherapy or intravesical instillation.nnnCONCLUSIONSnThe results suggest that up to 3 courses of repeated intravesical instillation of BCG are effective even for cases that initially did not respond, and that best results may be achieved if no other prior chemotherapy has been attempted.


Urological Research | 1998

Immunohistochemical evaluation of p53, proliferating cell nuclear antigen (PCNA) and bcl-2 expression during bacillus Calmette-Guerin (BCG) intravesical instillation therapy for superficial bladder cancers.

Takehiko Okamura; Hidetoshi Akita; Noriysau Kawai; Keiichi Tozawa; Yasuyuki Yamada; Kenjiro Kohri

Abstract Bacillus Calmette-Guerin (BCG) immunotherapy for superficial bladder cancer is now widespread, but non-effective cases are not uncommon and it has yet to be clarified why this is the case. In an attempt to cast light on this problem, we evaluated differences between effective and non-effective cases immunohistochemically using p53, proliferating cell nuclear antigen (PCNA), and bcl-2 antibodies. Between March 1988 and March 1996 a total of 79 superficial bladder cancer patients were treated with BCG intravesical instillation therapy after transurethral resection of bladder tumor (TUR-Bt). Of these, 19 demonstrated recurrence after the initial treatment. From the 60 remaining patients without recurrence, we randomly chose 19 additional cases and evaluated both series for p53, PCNA and bcl-2 immunohistochemical staining using formalin-fixed, paraffin-embedded tissues. For the recurrent cases, material taken prior and subsequent to BCG therapy was available for 17 of the 19 patients. Positive staining for p53 was noted for 42.1% (8/19) of both recurrent and non-recurrent cases, without any difference between the two. The rates for PCNA and bcl-2 were 52.6% (10/19) and 47.4% (9/19) in recurrent, and 36.8%u2009(7/19) and 78.9% (15/19) in non-recurrent cases, respectively. Thus, there was a significant difference for lower incidences of bcl-2 in recurrent cases (P=0.044). Values for p53 and bcl-2 were respectively 47.1% (8/17) and 41.2% (7/17) pre-treatment, and 52.9% (9/17) and 35.3% (6/17) post-treatment in the recurrence group. In contrast to the similarity in these results, PCNA positive cases were 52.9% (9/17) pre-treatment and 17.6% (3/17) post-treatment. These data suggest that there are differences between BCG-sensitive and BCG-resistant bladder cancers in terms of bcl-2 expression.


The Journal of Urology | 2016

Randomized Controlled Study of the Efficacy, Safety and Quality of Life with Low Dose bacillus Calmette-Guérin Instillation Therapy for Nonmuscle Invasive Bladder Cancer

Akira Yokomizo; Kanimoto Y; Takehiko Okamura; Seiichiro Ozono; Hirofumi Koga; Masatsugu Iwamura; Hiroshi Tanaka; Satoru Takahashi; Tomoyasu Tsushima; Hiro-omi Kanayama; Hideyuki Akaza; Nobuo Shinohara; Soichi Mugiya; Koichiro Nomata; Tsuyoshi Nakamura; Seiji Naito

PURPOSEnThe optimal dose of intravesical bacillus Calmette-Guérin for the treatment of nonmuscle invasive bladder cancer is controversial. We investigated if induction therapy with low dose bacillus Calmette-Guérin could achieve a complete response rate similar to that of standard dose bacillus Calmette-Guérin, with less toxicity and higher quality of life.nnnMATERIALS AND METHODSnAfter transurethral resection, patients with unresectable multiple nonmuscle invasive bladder cancer and/or carcinoma in situ were randomized to receive standard (80 mg) or low dose (40 mg) bacillus Calmette-Guérin instillation induction therapy (weekly, 8 times). The primary end point was noninferiority of low dose bacillus Calmette-Guérin with a null hypothesis of a 15% decrease in complete response rate. Secondary end points were recurrence-free survival, progression-free survival, overall survival, patient compliance, adverse events and quality of life using the EORTC QLQ-C30.nnnRESULTSnIn an intent to treat analysis of 166 patients the complete response rates for low dose and standard dose bacillus Calmette-Guérin were 79% (95% CI 0.70-0.88) and 85% (95% CI 0.77-0.92), respectively. Dunnett-Gent analysis revealed that the null hypothesis of inferiority of low dose bacillus Calmette-Guérin in terms of complete response could not be rejected (p = 0.119). However, there were no significant differences between the groups in terms of recurrence, progression and overall survival. Low dose bacillus Calmette-Guérin was associated with significantly less fever (p = 0.001) and micturition pain (p = 0.047), and significantly higher quality of life scores for global quality of life, role functioning and functional impairment.nnnCONCLUSIONSnThe noninferiority of low dose bacillus Calmette-Guérin was not proven. However, low dose bacillus Calmette-Guérin was associated with lower toxicity and higher quality of life compared to standard dose bacillus Calmette-Guérin in patients with nonmuscle invasive bladder cancer.


Urologia Internationalis | 1995

Detection and Monitoring of Simple Renal Cysts with Computed Tomography

Masayuki Tsugaya; Akihiro Kajita; Yutaro Hayashi; Takehiko Okamura; Kenjiro Kohri; Yoshiro Kato

We retrospectively investigated the incidence of simple renal cysts in 1,288 healthy subjects, and monitored the growth and formation of such cysts in 39 subjects using abdominal computed tomography (CT). Simple renal cysts were detected in 138 (10.7%) of the 1,288 subjects. The incidence of simple renal cysts increased significantly with the subjects age (p < 0.001). We found that cyst size increased significantly with age and over time on serial CT studies (p < 0.001). Exoparenchymal cysts, comprising greater than 50% of extraparenchymal lesions, were significantly larger than endoparenchymal cysts (p < 0.001), and showed a greater tendency to increase in size over time.


Urologia Internationalis | 2001

Intravesical Combined Chemoimmunotherapy with Epirubicin and Bacillus Calmette-Guérin Is Not Indicated for Superficial Bladder Cancer

Keiichi Tozawa; Takehiko Okamura; Shoichi Sasaki; Noriyasu Kawai; Yasunori Ito; Yutaro Hayashi; Kenjiro Kohri

Purpose: The short-term effects of intravesical chemoimmunotherapy with epirubicin and bacillus Calmette-Guérin (BCG) administered repeatedly for prophylaxis of recurrence of superficial bladder cancer (pTa, pT1) were investigated in 24 patients aged a median of 70 years between March 1996 and February 1999, and were compared with those of BCG monotherapy in 50 patients from March 1990 to February 1999. Patients and Methods: The patients underwent intravesical instillation of the Tokyo strain BCG with or without epirubicin after transurethral resection (TUR) of bladder cancer. For the combined treatment, at 1–2 weeks after TUR, epirubicin (40 mg) and BCG (80 mg) were istilled into the bladder by turns once a week for 12 weeks. For the group receiving only BCG, 80-mg instillations were done with the same schedule. Thereafter, the patients were followed by cystoscopy and urinary cytology every 3 months for up to 3 years after intravesical therapy. Results and Conclusions: At 2 years after treatment, the simple recurrence rate was 26.1% (6/23) in patients with chemoimmunotherapy and 32.0% (16/50) in BCG-treated patients. Adverse reactions, including increased frequency of urination, urgency and miction pain, were observed in 18 patients (85.7%) undergoing chemoimmunotherapy and 58.0% undergoing BCG monotherapy. One patient receiving chemoimmunotherapy was withdrawn from treatment because of symptoms of severe bladder irritation due to the instillation. Intravesical chemoimmunotherapy using epirubicin and BCG was finally found to be inferior in comparison with BCG monotherapy for the prophylaxis of recurrence of superficial bladder cancer.


Cancer Chemotherapy and Pharmacology | 1994

Single instillation of hydroxypropylcellulose-doxorubicin as treatment for superficial bladder carcinoma

Kousuke Ueda; Hiroshi Sakagami; Yasuhiko Masui; Takehiko Okamura

A single instillation of hydroxypropylcellulose (HPC)-doxorubicin (20 mg/20 ml) was performed in 20 patients with superficial bladder carcinoma. The therapeutic effect was assessed by cystoscopy at 14–30 days after the instillation, and the residual tumor tissue was resected by transurethral resection (TUR) when possible. The results obtained for the therapeutic effect were as follows: a complete response (CR), in 7 cases (35%); a reduction in size of more than 50% (partial response, PR), in 6 cases (30%); and a reduction of less than 25% in size (no change, NC), in 7 cases (35%). Combined intravesical instillation of HPC-doxorubicin and local hyperthermia using a Thermotron RF-8 was performed in 11 patients with recurrent superficial bladder carcinoma. The total number of treatment courses ranged from three to five per patient. The results obtained for the effect of this combined treatment were as follows: a CR, in 6 cases (54.5%); a PR, in 3 cases (27.3%); and NC, in 2 cases (18.2%). Therefore, the combination of intravesical instillation of HPC-doxorubicin and local hyperthermia was more effective against superficial bladder carcinoma than the single instillation of the chemotherapeutic agent alone.


Virchows Archiv B Cell Pathology Including Molecular Pathology | 1988

Comparison of enzyme phenotypes in human bladder tumours and experimentally induced hyperplastic and neoplastic lesions of the rat urinary bladder: a combined histochemical and immunohistochemical approach

Hiroyuki Tsuda; Tadashi Inoue; Makoto Asamoto; Shoji Fukushima; Nobuyuki Ito; Takehiko Okamura; Kazuo Ohtaguro; Hiroto Washida; Kimihiko Satoh; Zahra Amelizad; Franz Oesch

SummaryThe expression of a number of enzymes involved in drug metabolism, membrane function etc. was compared in hyperplastic and neoplastic lesions of the rat bladder and in human bladder tumours. Transitional cell carcinomas (TCC) in both rat and Man were characterized by decreased alkaline phosphatase (ALP) and increased gammaglutamyl transpeptidase (GGT), β-glucuronidase (β-Gl), succinate dehydrogenase (SD) and glucose-6-phosphate dehydrogenase (G6PD) activities. In addition, binding for antibodies specific for different cytochrome P-450 species (UT50, PB3a, MC1, MC2) and microsomal epoxide hydrolase (mEHb) was elevated in both murine and human tumours. Comparison of the enzyme phenotype in hyperplastic lesions induced by freeze ulceration or uracil administration with that in preneoplastic papillary or nodular hyperplasia (PNH) and TCC suggested, however, that most of the alteration in enzyme content or activity was non-specific and related to requirements for epithelial cell proliferation. On the other hand, the decreased ALP, and increased GGT and β - Gl activity appeared more directly related to neoplastic transformation. The results suggested that qualitative differences exist between reactive hyperplasia and preneoplastic or neoplastic lesions in the urinary bladder. The finding of increased cytochrome P-450, in clear contrast to the reduction characteristic of preneoplastic hepatic lesions, may be important with regard to the observed difference in neoplastic transformation between the bladder and liver in response to drug metabolising enzyme inducers.


International Journal of Clinical Oncology | 2014

Gemcitabine and docetaxel, an effective second-line chemotherapy for lung metastasis of urothelial carcinoma

Taku Naiki; Noriyasu Kawai; Yoshihiro Hashimoto; Takehiko Okamura; Ryosuke Ando; Takahiro Yasui; Atsushi Okada; Toshiki Etani; Keiichi Tozawa; Kenjiro Kohri

BackgroundThe objective of this study was to evaluate the efficacy of a gemcitabine and docetaxel (GD) combination as a second-line treatment for patients with metastatic urothelial carcinoma (UC) after failure of first-line treatment with platinum-based chemotherapy.MethodsFrom June 2006 to January 2012, 38 patients with metastatic UC previously treated with platinum-based chemotherapy received GD therapy. This consisted of gemcitabine 800xa0mg/m2 and docetaxel 40xa0mg/m2 on days 1 and 8 of each 21-day cycle as second-line chemotherapy. All the patients were evaluated for toxicity and assessed every cycle by imaging. We analyzed the efficacy of GD as second-line chemotherapy in the follow-up study.ResultsThe median number of GD treatment cycles was 4 (range 2–9); the objective response rate was 47.4xa0%; and the median progression-free survival and median overall survival were 4.1 and 10.8xa0months, respectively. Univariate and multivariate analyses on the GD treated group showed that the existence of lung metastases was the only prognostic factor for tumor response. Grade 3 treatment-related toxicity included neutropenia (31.6xa0%) and thrombocytopenia (15.8xa0%), and only one patient with grade 4 toxicity had thrombocytopenia (2.6xa0%).ConclusionsThe GD regimen as second-line chemotherapy was especially effective for lung metastatic UC and yielded favorable results in patients whose first-line platinum-based chemotherapy had failed. Given the safety and benefit profile seen in this study, a large prospective study is warranted to consider the potential utility of GD chemotherapy as a second-line for UC.

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Taku Naiki

Nagoya City University

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K. Kohri

Nagoya City University

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