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Dive into the research topics where Narihito Seki is active.

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Featured researches published by Narihito Seki.


BJUI | 2007

Randomized, double‐blind, placebo‐ and propiverine‐controlled trial of the once‐daily antimuscarinic agent solifenacin in Japanese patients with overactive bladder

Osamu Yamaguchi; Eiji Marui; Hidehiro Kakizaki; Naoki Itoh; Takashi Yokota; Hiroshi Okada; Seiichiro Ozono; Momokazu Gotoh; Takahide Sugiyama; Narihito Seki; Masaki Yoshida

To compare solifenacin succinate (5 and 10 mg once‐daily) to placebo and propiverine hydrochloride (20 mg once‐daily), respectively, in Japanese patients with overactive bladder syndrome (OAB).


BJUI | 2014

Phase III, randomised, double-blind, placebo-controlled study of the β3-adrenoceptor agonist mirabegron, 50 mg once daily, in Japanese patients with overactive bladder.

Osamu Yamaguchi; Eiji Marui; Hidehiro Kakizaki; Yukio Homma; Yasuhiko Igawa; Masayuki Takeda; Osamu Nishizawa; Momokazu Gotoh; Masaki Yoshida; Osamu Yokoyama; Narihito Seki; Yasushi Ikeda; Sumito Ohkawa

To evaluate the efficacy and safety of the β3‐adrenoceptor agonist mirabegron, in a Japanese population with overactive bladder (OAB).


Urology | 2011

Solifenacin as add-on therapy for overactive bladder symptoms in men treated for lower urinary tract symptoms--ASSIST, randomized controlled study.

Osamu Yamaguchi; Hidehiro Kakizaki; Yukio Homma; Masayuki Takeda; Osamu Nishizawa; Momokazu Gotoh; Osamu Yokoyama; Narihito Seki; Masaki Yoshida

OBJECTIVES To assess the efficacy and safety of solifenacin add-on therapy to tamsulosin in lower urinary tract symptoms (LUTS) men with residual overactive bladder (OAB) symptoms despite tamsulosin monotherapy. METHODS In this randomized, multicenter, double-blind study, male LUTS patients aged≥50 years with urgency episodes/24 hours≥2 and micturitions/24 hours≥8 were randomized to 3 groups: 12-weeks tamsulosin plus placebo (TAM+PBO), tamsulosin plus solifenacin 2.5 mg (TAM+SOL), and tamsulosin plus solifenacin 5 mg (TAM+SOL). Changes from baseline to end of treatment in the number of urgency episodes/24 hours (primary endpoint), micturitions, nocturia, urgency incontinence episodes, International Prostate Symptom Scores (IPSS), and Overactive Bladder Symptom Score (OABSS) were compared between the TAM+SOL groups and TAM+PBO. Safety was assessed on adverse events, postvoid residual volume, and maximal urinary flow rate (Qmax.). RESULTS Six-hundred thirty-eight men were randomized. Urgency was reduced by 2.2 and 2.4 episodes in the TAM+SOL 2.5 and 5 mg groups, respectively. The TAM+SOL 5 mg group showed significant improvement compared with TAM+PBO (-2.4 vs -1.9, P=.049). The number of micturitions in both TAM+SOL groups were significantly reduced compared with TAM+PBO (both P<.001). IPSS storage symptom score and OABSS significantly improved in both TAM+SOL groups compared with TAM+PBO. Changes in IPSS voiding symptom score and Qmax. were similar in all groups. Four patients (1.9%) in the TAM+SOL 5 mg group had urinary retention, but all recovered after catheterization. CONCLUSIONS In male LUTS patients with residual OAB symptoms despite tamsulosin monotherapy, TAM+SOL showed efficacy on urgency, which represents OAB symptoms and was well tolerated.


Urology | 2011

Assessment of overactive bladder symptoms: comparison of 3-day bladder diary and the overactive bladder symptoms score.

Yukio Homma; Hidehiro Kakizaki; Osamu Yamaguchi; Tomonori Yamanishi; Osamu Nishizawa; Osamu Yokoyama; Masayuki Takeda; Narihito Seki; Masaki Yoshida

OBJECTIVES To compare the Overactive Bladder Symptom Score (OABSS) and a bladder diary as a tool for assessing symptoms of overactive bladder (OAB). METHODS Treatment-naive OAB patients received an antimuscarinic agent, solifenacin. At baseline and 12 weeks after treatment, patients completed a 3-day bladder diary and the OABSS. Relationships between the 2 methods were evaluated by comparison of changes after treatment, agreement between variables and correlation between changes. RESULTS In total, 79 patients (42 male and 37 female, mean age 71.1 years) were included in the analysis. Statistically significant improvements were noted for all the OABSS and the corresponding diary variables. The effect size (ES) was largest for the OABSS urgency score (2.00), followed by the OABSS total score (1.54), and then by the diary urgency score (0.92). All of the ESs for the OABSS, except daytime frequency, were larger than those of the corresponding diary variables. The standard response means followed a similar pattern to the ESs. A fairly good agreement between OABSS items and the corresponding diary variables was found at baseline and 12 weeks (kappa coefficient, 0.33-0.80). High correlations (Spearmans rho, ≥ 0.5) between changes in OABSS items and the corresponding diary variables were found for urgency incontinence and night-time frequency. CONCLUSIONS The OABSS is highly sensitive to treatment-related changes of OAB symptoms. Because of its simplicity and dependability, the OABSS can be an alternative to a bladder diary for symptom and efficacy assessment in daily clinical practice.


International Journal of Urology | 2011

Outline of JUA clinical guidelines for benign prostatic hyperplasia

Yukio Homma; Momokazu Gotoh; Osamu Yokoyama; Naoya Masumori; Akihiro Kawauchi; Tomonori Yamanishi; Narihito Seki; Toshiyuki Kamoto; Atsushi Nagai; Seiichiro Ozono

The Japanese Urological Association has developed Clinical Guidelines for Benign Prostatic Hyperplasia (BPH) for men with suspected BPH, which have been abridged and translated into English. This article is a shortened version of the English translation. The Guidelines were formulated on the basis of evidence retrieved from the PubMed database between 1995 and 2009, as well as other relevant sources. The target patients of these Guidelines are men with suspected BPH, and the target users are urologists. A mandatory assessment should include a medical history, a physical examination, the completion of symptom and quality of life questionnaires, urinalysis, prostate ultrasonography, measurement of serum prostate specific antigen and postvoid residual urine, and an uroflowmetry. Optional tests include a bladder diary, the measurement of serum creatinine, and upper urinary tract ultrasonography. Care should be taken to not overlook coexisting diseases such as an infection or malignancy that may obscure the diagnosis. Treatment should consist of conservative therapy or the use of medications such as α1‐adrenoceptor antagonists, or both. The use of 5α‐reductase inhibitors or anticholinergic agents should be considered in patients with an enlarged prostate (>30 mL) or overactive bladder symptoms (overactive bladder symptom score ≥6), respectively. Surgical intervention is indicated when non‐surgical treatments fail to provide sufficient symptomatic relief and bladder outlet obstruction is highly suspected.


The Journal of Urology | 1992

The effect of experimental urethral obstruction and its reversal on changes in passive electrical properties of detrusor muscle.

Narihito Seki; Omer Karim; Jacek L. Mostwin

The passive electrical properties of guinea pig detrusor muscle were studied in order to determine how bladder outflow obstruction and reversal might modify the electrical activity of the bladder and, thus, contractility. Experimental bladder outflow obstruction was produced in guinea pigs and resulted in an increase in bladder weight with a decrease in spontaneous electrical activity, membrane time constant and space constant. In addition, the membrane Na-K pump activity increased with obstruction. Following reversal of obstruction, bladder weight gain associated with obstruction was only partially reversible. The decrease in the membrane time constant induced by obstruction was almost fully reversible following release of obstruction. In contrast, the membrane space constant which reflects spread of current, in addition to spontaneous electrical activity, were only partially reversible. The membrane Na-K pump activity of the detrusor muscle decreased to control levels following reversal of bladder outflow obstruction. There was no significant change in the resting membrane potential of detrusor smooth muscle with either obstruction or following reversal of obstruction. These results suggest, that, the changes in the bladder smooth muscle membrane electrical properties induced by experimental bladder outflow obstruction are only partially reversible following release of obstruction. Furthermore, the results suggest that, the dysfunctional cystometric patterns associated with bladder outflow obstruction might not only be due to changes in detrusor innervation but, fundamental reorganization of the detrusors electrical syncytium with irreversible suppression of cell-to-cell transfer of electrical activity.


BJUI | 2015

Safety and efficacy of mirabegron as ‘add‐on’ therapy in patients with overactive bladder treated with solifenacin: a post‐marketing, open‐label study in Japan (MILAI study)

Osamu Yamaguchi; Hidehiro Kakizaki; Yukio Homma; Yasuhiko Igawa; Masayuki Takeda; Osamu Nishizawa; Momokazu Gotoh; Masaki Yoshida; Osamu Yokoyama; Narihito Seki; Akira Okitsu; Takuya Hamada; Akiko Kobayashi; Kentarou Kuroishi

To examine the safety and efficacy of mirabegron as ‘add‐on’ therapy to solifenacin in patients with overactive bladder (OAB).


Molecular Endocrinology | 2010

Peroxisome proliferator-activated receptor γ coactivator-1α interacts with the androgen receptor (AR) and promotes prostate cancer cell growth by activating the AR

Masaki Shiota; Akira Yokomizo; Yasuhiro Tada; Junichi Inokuchi; Katsunori Tatsugami; Kentaro Kuroiwa; Takeshi Uchiumi; Naohiro Fujimoto; Narihito Seki; Seiji Naito

There are currently few successful therapies for castration-resistant prostate cancer (CRPC). CRPC is thought to result from augmented activation of the androgen/androgen receptor (AR) signaling pathway, which could be enhanced by AR cofactors. In this study, peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) was found to be an AR cofactor. PGC-1alpha interacted with the N-terminal domain of AR, was involved in the N- and C-terminal interaction of AR, and enhanced the DNA-binding ability of AR to androgen-responsive elements in the prostate-specific antigen enhancer and promoter regions to increase the transcription of AR target genes. Silencing of PGC-1alpha suppressed cell growth of AR-expressing prostate cancer (PCa) cells by inducing cell-cycle arrest at the G(1) phase, similar to inhibition of androgen/AR signaling. Furthermore, PGC-1alpha knock-down also suppressed cell growth in the castration-resistant LNCaP-derivatives. These findings indicate that PGC-1alpha is involved in the proliferation of AR-expressing PCa cells by acting as an AR coactivator. Modulation of PGC-1alpha expression or function may offer a useful strategy for developing novel therapeutics for PCa, including CRPC, which depends on AR signaling by overexpressing AR and its coactivators.


Cancer Science | 2010

Foxo3a expression and acetylation regulate cancer cell growth and sensitivity to cisplatin

Masaki Shiota; Akira Yokomizo; Eiji Kashiwagi; Yasuhiro Tada; Junichi Inokuchi; Katsunori Tatsugami; Kentaro Kuroiwa; Takeshi Uchiumi; Narihito Seki; Seiji Naito

Many advanced cancers receive cisplatin‐based chemotherapy. However, cisplatin resistance is a major obstacle for cancer chemotherapy. Foxo3a is a member of the Foxo transcription factor family, which modulates the expression of genes involved in DNA damage repair, apoptosis, and other cellular processes. In this study, we found that cisplatin‐resistant cells were more sensitive to the anticancer agent mithramycin than their parental cells, and had a decreased level of Foxo3a expression. Foxo3a knockdown increased cell proliferation and resistance to cisplatin. On the other hand, mithramycin stimulated Foxo3a expression through reactive oxygen species production and sensitized cells to cisplatin, which was abolished by Foxo3a knockdown, while the acetylation status of Foxo3a was decreased in response to cisplatin treatment and was lower in cisplatin‐resistant cells. Knockdown of Foxo3a‐associated acetyltransferase p300 promoted cancer‐cell growth and cisplatin resistance. In addition, non‐acetylation‐mimicking Foxo3a overexpression decreased cancer cell growth and sensitized cells to cisplatin less than wild‐type Foxo3a overexpression. The current work may contribute to the evaluation of the therapeutic potential of inducing the Foxo3a pathway and acetylating the Foxo3a transcription factor, and lead to the reevaluation of cancer treatments based on mithramycin.


Neurourology and Urodynamics | 2009

Analysis of the prognostic factors for overactive bladder symptoms following surgical treatment in patients with benign prostatic obstruction

Narihito Seki; Kohei Yuki; Mineo Takei; Akito Yamaguchi; Seiji Naito

To identify the prognostic variables concerning the improvement of overactive bladder syndrome (OAB) related symptoms following a transurethral resection of the prostate (TURP) in patients with benign prostatic obstruction (BPO).

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Mineo Takei

University of Yamanashi

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Hidehiro Kakizaki

Asahikawa Medical University

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