Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Kentaro Takezawa is active.

Publication


Featured researches published by Kentaro Takezawa.


International Journal of Urology | 2009

Surveillance following orchiectomy for stage I testicular seminoma: Long-term outcome

Takahiro Yoshida; Ken-ichi Kakimoto; Kentaro Takezawa; Yasuyuki Arai; Yutaka Ono; Norio Meguro; Toshiaki Kinouchi; Kazuo Nishimura; Michiyuki Usami

Objectives:  To report the long‐term outcome of surveillance for stage I seminoma at a single institution in Japan.


Scientific Reports | 2016

Authentic role of ATP signaling in micturition reflex.

Kentaro Takezawa; Makoto Kondo; Hiroshi Kiuchi; Norichika Ueda; Tetsuji Soda; Shinichiro Fukuhara; Tetsuya Takao; Yasushi Miyagawa; Akira Tsujimura; Kazumasa Matsumoto-Miyai; Yusuke Ishida; Hiromitsu Negoro; Osamu Ogawa; Norio Nonomura; Shoichi Shimada

Adenosine triphosphate (ATP) is a signaling molecule that regulates cellular processes. Based on previous studies of bladder function over the past decade, bladder ATP signaling was thought to have an essential role in the normal micturition reflex. In this study, we performed detailed analyses of bladder function in purinergic receptor-deficient mice using the automated voided stain on paper method and video-urodynamics. Unexpectedly, a lack of P2X2 or P2X3 receptors did not affect bladder function under normal physiological conditions, indicating that bladder ATP signaling is not essential for normal micturition reflex. In contrast, we found that lipopolysaccharide (LPS) induced markedly high levels of ATP release from the urothelium. In addition, LPS-induced rapid bladder hyperactivity was attenuated in P2X2−/− and P2X3−/− mice. Contrary to the previous interpretation, our present findings indicate that bladder ATP signaling has a fundamental role in the micturition reflex, especially in bladder dysfunction, under pathological conditions. Therefore, the bladder ATP signaling pathway might be a highly promising therapeutic target for functional bladder disorders. This study newly defines an authentic role for bladder ATP signaling in the micturition reflex.


Urology | 2013

Correlation between overactive bladder symptoms and quality of life in Japanese male patients: focus on nocturia.

Tetsuya Takao; Akira Tsujimura; Hiroshi Kiuchi; Kentaro Takezawa; Hidenobu Okuda; Keisuke Yamamoto; Shinichiro Fukuhara; Yasushi Miyagawa; Norio Nonomura

OBJECTIVE To elucidate the effects of nocturia, one of the most bothersome of symptoms, on health-related quality of life (QOL), we examined the correlation between nocturia-specific QOL and other lower urinary tract symptoms (LUTS). METHODS Patients who visited our hospital complaining of LUTS were assessed retrospectively. A total of 259 men with LUTS answered the following questionnaires: International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score (OABSS), Nocturia QOL questionnaire (NQOL), and the Benign Prostatic Hyperplasia Impact Index (BII). The Spearman rank correlation coefficient was used to examine the correlation between NQOL total score and NQOL subdomain scores of sleep/energy and bother/concern and scores of other questionnaires. We then compared NQOL score in patients with or without OAB symptoms. RESULTS The NQOL total score correlated significantly not only with IPSS total, IPSS storage symptoms, IPSS voiding symptoms, and QOL index but also with the OABSS and BII scores. The NQOL total score was significantly higher in the non-OAB vs OAB patients, indicating that OAB may deteriorate QOL as it relates to nocturia. In nocturia subgroups 0 to 2 (mild nocturia), NQOL score was significantly higher in non-OAB than in OAB patients, whereas in the nocturia subgroups 3 to 5 (severe nocturia), NQOL score was not significantly different between non-OAB and OAB patients. CONCLUSION The NQOL total score correlated significantly with IPSS, OABSS, and BII scores. Symptoms of OAB and bother due to benign prostatic hyperplasia might affect QOL in patients with nocturia.


International Journal of Urology | 2014

Sexual life of Japanese patients with erectile dysfunction taking phosphodiesterase type 5 inhibitors: An Internet survey using the Psychological and Interpersonal Relationship Scales-Short Form questionnaire

Akira Tsujimura; Hiroshi Kiuchi; Tetsuji Soda; Kentaro Takezawa; Hidenobu Okuda; Shinichiro Fukuhara; Tetsuya Takao; Norio Nonomura; Yasushi Miyagawa

To investigate details of sexual function of erectile dysfunction in Japanese patients taking phosphodiesterase type 5 inhibitors.


American Journal of Physiology-renal Physiology | 2014

Combination of bladder ultrasonography and novel cystometry method in mice reveals rapid decrease in bladder capacity and compliance in LPS-induced cystitis

Kentaro Takezawa; Makoto Kondo; Hiroshi Kiuchi; Tetsuji Soda; Tetsuya Takao; Yasushi Miyagawa; Akira Tsujimura; Norio Nonomura; Shoichi Shimada

Various animal models have been used in research into bladder dysfunction, and in vivo cystometry is a common method to analyze bladder function in animals. However, it is rather difficult to perform reliably in small animals. Transabdominal bladder ultrasonography combined with cystometry in urethane-anesthetized mice have revealed physical inhibition of bladder wall movement by a bladder catheter conventionally placed in the bladder apex. For reliable evaluation of mouse lower urinary tract function, we established a novel cystometry method in which a catheter was placed in the bladder anterior wall, in combination with bladder ultrasonography. This new method allowed the bladder to be well distended (i.e., larger maximum bladder capacity, lower pressure threshold, higher voided volume, and higher bladder compliance compared with conventional methods), which reflected more spontaneous voiding than conventional cystometry methods. We also demonstrated the usefulness of bladder ultrasonography for analysis of mouse bladder function, especially bladder dynamics, maximum bladder capacity, and post-voiding residual volume. We analyzed bladder functional changes in lipopolysaccharide (LPS)-induced cystitis by combining bladder ultrasonography and this new cystometry method. Bladder ultrasonography revealed a rapid decrease in bladder capacity, and cystometry showed a rapid decrease in voided volume due to intravesical LPS instillation. This new cystometry method also revealed a rapid decrease in bladder compliance caused by LPS instillation, which was not detectable by conventional methods. The combination of ultrasonography and the new cystometry method may become a powerful tool for analysis of mouse bladder function and could contribute to the development of new treatments for bladder dysfunction.


Urology | 2015

Histologic Evaluation of Human Benign Prostatic Hyperplasia Treated by Dutasteride: A Study by Xenograft Model With Improved Severe Combined Immunodeficient Mice

Akira Tsujimura; Shinichiro Fukuhara; Tetsuji Soda; Kentaro Takezawa; Hiroshi Kiuchi; Tetsuya Takao; Yasushi Miyagawa; Norio Nonomura; Shigeki Adachi; Yoriko Tokita; Taisei Nomura

OBJECTIVE To evaluate histologic change in human prostate samples treated with dutasteride and to elucidate direct effects of dutasteride on human prostate tissue, the present study was conducted by using a xenograft model with improved severe combined immunodeficient (super-SCID) mice, although it is well known that dutasteride reduces prostate volume. METHODS After establishment of a xenograft model of human benign prostatic hyperplasia in morphology and function, samples implanted into super-SCID mice with and without dutasteride were evaluated pathohistologically at 2 and 6 months after initiation of dutasteride administration. RESULTS The proliferative index evaluated by Ki-67 staining was significantly lower in the dutasteride group than the control at 2 and 6 months after administration. Apoptotic index evaluated by the terminal transferase TdT-mediated dUTP-biotin nick end labeling staining was higher in the dutasteride group than the control at 2 and 6 months after administration. Quick scores in the dutasteride group for staining of both cyclooxygenase-2 (Cox-2) and Ras homolog gene family, member A (RhoA) were significantly lower than those in the control group at 2 and 6 months after administration. CONCLUSION Dutasteride inhibits cell proliferation and induces apoptosis of prostatic cells, causing a reduced prostate volume. Furthermore, decreased expression of Cox-2 and RhoA within benign prostatic hyperplasia tissue by dutasteride may induce an early effect on improvement of lower urinary tract symptoms, probably by attenuating inflammation reaction of the prostate and decreasing intraurethral pressure, other than the mechanism of reduced prostate volume.


Neurourology and Urodynamics | 2017

Urothelial ATP signaling: what is its role in bladder sensation?

Kentaro Takezawa; Makoto Kondo; Norio Nonomura; Shoichi Shimada

Bladder functional disorders are common health problems; however, their pathologies are poorly understood. Adenosine triphosphate (ATP) released from the urothelium has been suggested to have an essential role in the micturition reflex, and its involvement in bladder functional disorders has been intensively investigated. Here, we review the latest advances in research on urothelial ATP signaling.


Human Reproduction | 2017

Systematic characterization of human testis-specific actin capping protein β3 as a possible biomarker for male infertility

Tetsuji Soda; Yasushi Miyagawa; N. Ueda; Kentaro Takezawa; H. Okuda; Shinichiro Fukuhara; Kazutoshi Fujita; Hiroshi Kiuchi; Motohide Uemura; Yoshio Okamoto; Akira Tsujimura; Hiromitsu Tanaka; Norio Nonomura

STUDY QUESTION Is actin capping protein (CP) β3 involved in human spermatogenesis and male infertility? SUMMARY ANSWER Human CPβ3 (hCPβ3) is expressed in testis, changes its localization dynamically during spermatogenesis, and has some association with male infertility. WHAT IS KNOWN ALREADY The testis-specific α subunit of CP (CPα3) was previously identified in human, and mutations in the cpα3 gene in mouse were shown to induce malformation of the sperm head and male infertility. However, CPβ3, which is considered to be a heterodimeric counterpart of CPα3, has been neither characterized in human nor reported in association with male infertility. STUDY DESIGN, SIZE, DURATION To confirm the existence of CPβ3 in human testis, fresh semen samples from proven fertile men were analyzed. To investigate protein expression during spermatogenesis, cryopreserved testis obtained from men with obstructive azoospermia were examined by immunofluorescent analysis. To assess the association of CP with male infertility, we compared protein expression of human CPα3 (hCPα3) and hCPβ3 using immunofluorescent analysis of cryopreserved sperm between men with normozoospermia (volunteers: Normo group, n = 20) and infertile men with oligozoospermia and/or asthenozoospermia (O + A group, n = 21). PARTICIPANTS/MATERIALS, SETTING, METHODS The tissue-specific expression of hCPβ3 was investigated by RT-PCR and Western blot analysis. To investigate whether hCPα3 and hCPβ3 form a heterodimer, a tandem expression vector containing hcpα3 tagged with monomeric red fluorescent protein 1 and hcpβ3 tagged with enhanced green fluorescent protein in a single plasmid was constructed and analyzed by co-immunoprecipitation (Co-IP) assay. The protein expression profiles of hCPα3 and hCPβ3 during spermatogenesis were examined by immunohistochemical analysis using human spermatogenic cells. The protein expressions of hCPα3 and hCPβ3 in sperm were compared between the Normo and O + A groups by immunohistochemical analysis. MAIN RESULTS AND THE ROLE OF CHANCE RT-PCR showed that mRNA of hcpβ3 was expressed exclusively in testis. Western blot analysis detected hCPβ3 with anti-bovine CPβ3 antibody. Co-IP assay with recombinant protein showed that hCPα3 and hCPβ3 form a protein complex. At each step during spermatogenesis, the cellular localization of hCPβ3 changed dynamically. In spermatogonia, hCPβ3 showed a slight signal in cytoplasm. hCPβ3 expression was conspicuous mainly from spermatocytes, and hCPβ3 localization dynamically migrated from cytoplasm to the acrosomal cap and acrosome. In mature spermatozoa, hCPβ3 accumulated in the postacrosomal region and less so at the midpiece of the tail. Double-staining analysis revealed that hCPα3 localization was identical to hCPβ3 at every step in the spermatogenic cells. Most spermatozoa from the Normo group were stained homogenously by both hCPα3 and hCPβ3. In contrast, significantly more spermatozoa in the O + A versus Normo group showed heterogeneous or lack of staining for either hCPα3 or hCPβ3 (abnormal staining) (P < 0.001). The percentage of abnormal staining was higher in the O + A group (52.4 ± 3.0%) than in the Normo group (31.2 ± 2.5%). Even by confining the observations to morphologically normal spermatozoa selected in accordance with Davids criteria, the percentage of abnormal staining was still higher in the O + A group (39.9 ± 2.9%) versus the Normo group (22.5 ± 2.1%) (P < 0.001). hCPβ3 in conjunction with hCPα3 seemed to play an important role in spermatogenesis and may be associated with male infertility. LARGE SCALE DATA Not applicable. LIMITATIONS REASONS FOR CAUTION Owing to the difficulty of collecting fresh samples of human testis, we used cryopreserved samples from testicular sperm extraction. To examine the interaction of spermatogenic cells or localization in seminiferous tubules, fresh testis sample of healthy males are ideal. WIDER IMPLICATIONS OF THE FINDINGS The altered expression of hCPα3 and hCPβ3 may not only be a cause of male infertility but also a prognostic factor for the results of ART. They may be useful biomarkers to determine the fertilization ability of human sperm in ART. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by a Grant-in-Aid for Young Scientists (B) from the Japan Society for the Promotion of Science (JP16K20133). The authors declare no competing interests.


The Journal of Urology | 2018

PD19-08 BLADDER UROTHELIUM TRIGGERS AN IMMEDIATE DEFENSIVE RESPONSE AGAINST BACTERIAL LIPOPOLYSACCHARIDE VIA ATP SIGNALING

Norichika Ueda; Makoto Kondo; Hiroshi Kiuchi; Yusuke Inagaki; Kentaro Takezawa; Shinichiro Fukuhara; Shoichi Shimada; Norio Nonomura

were glutamatergic, caused bladder contraction and an increase in the probability of micturition. We asked whether these CRH neurons alone could produce co-ordinated micturition. METHODS: To target PMC in CRH-ires-CRE mice, stereotaxic injections of Cre-inducible vectors (AAV-EF1a-DIO-hChR2-mCherry or AAV-hSyn-DIO-hm4D-mcherry) to enabled light-activation or clozapine N-oxide (CNO)-induced neuronal silencing. Subsequently under urethane anaesthesia an optic fibre was placed above PMC for optogenetic stimulation. Bladder pressure was monitored with a PE-50 catheter and EUS-EMG was recorded with implanted electrodes. RESULTS: The vectors allowed selective expression of ChR2/ DREADD within CRH+ PMC neurons (Fig. 1a). Optogenetic activation of PMC-CRH neurons (473 nm, 5-30ms x 2.5-20Hz for 5s) reliably evoked transient non-voiding bladder contractions (“opto-NVCs”, 1.6 ? 0.4 mmHg, 20ms-pulse x 20Hz, n1⁄49) of an empty bladder (Fig. 1b). Surprisingly there was little relationship between opto-stimulus parameters and opto-NVC amplitude unlike response probability. A comparison of opto-NVCs and spontaneous NVCs showed that the optogenetic activation did not activate the EUS. Opto-stimulation when the bladder was full could trigger voids. Chemogenetic inhibition of the PMC-CRH neurons with CNO (5ug/kg) reversibly inhibited voiding. CONCLUSIONS: These data support the role of the PMC CRH neurons as being pre-parasympathetic neurons that are required for voiding but they are not part of EUS motor control. The PMC-CRH neurons are not high-fidelity controllers of micturition but they do influence timing of events.


Biochemical and Biophysical Research Communications | 2018

Intravesical ATP instillation induces urinary frequency because of activation of bladder afferent nerves without inflammatory changes in mice: A promising model for overactive bladder

Norichika Ueda; Makoto Kondo; Kentaro Takezawa; Hiroshi Kiuchi; Yosuke Sekii; Yusuke Inagaki; Tetsuji Soda; Shinichiro Fukuhara; Kazutoshi Fujita; Motohide Uemura; Ryoichi Imamura; Yasushi Miyagawa; Norio Nonomura; Shoichi Shimada

ATP in the suburothelial layer is released from the bladder urothelium by mechanical stimuli. ATP directly activates purinergic receptors that are expressed on primary bladder afferent neurons and induces the micturition reflex. Although ATP is also released to the bladder lumen from the bladder urothelium, the role of ATP in the bladder lumen is unknown. Recently, clinical studies have reported that urinary ATP levels are much higher in patients with an overactive bladder than healthy controls. These results suggest that ATP in the bladder lumen is also involved in the micturition reflex. In this study, we performed intravesical ATP instillation in the mouse bladder. We evaluated urinary function with novel reliable methods using improved cystometry and ultrasonography, which we previously established. We found that intravesical ATP instillation induced urinary frequency because of activation of bladder afferent nerves without inflammatory changes in the bladder or an increase in post-void residual urine. These results suggest that not only ATP in the suburothelial layer, but also ATP in the bladder lumen, are involved in enhancement of the micturition reflex.

Collaboration


Dive into the Kentaro Takezawa's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge