Masami Nantani
Hokkaido University
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Featured researches published by Masami Nantani.
The Journal of Urology | 1994
Kaname Ameda; Tomohiko Koyanagi; Masami Nantani; Koutaro Taniguchi; Tadashi Matsuno
Preoperative water cystometrograms in 437 patients with benign prostatic hyperplasia (BPH) were examined in a retrospective study. The cystometrographic results were analyzed regarding the preoperative clinical features: patient age, presence or absence of urinary incontinence, history of urinary retention and rate of residual urine. The prognostic value in improvement in voiding difficulty and postoperative urinary incontinence was also analyzed at 1 and 6 months after elective prostatectomy. Subjective symptoms of the patients were the primary reasons for prostatectomy, the majority of which were performed by a single competent resectionist (K. T.) who evaluated the outcome but was blinded to the cystometric findings. Of these patients 263 (60.2%) had detrusor instability (group 1), while 174 did not (group 2). Vesical denervation supersensitivity to bethanechol chloride was noted in 47 of 375 patients (12.5%). The difference in clinical features was significant between the 2 groups, with group 1 showing older patient age (p < 0.01), and a greater incidence of urinary incontinence (p < 0.001) and retention (p < 0.001). The difference between groups 1 and 2 in mean bladder capacity (p < 0.01), compliance (p < 0.01) and a greater positive rate of vesical denervation supersensitivity (p < 0.001) was also significant. The clinical and cystometrographic parameters studied worsened with advancing patient age. Although the majority of the patients (94.7%) were relieved of obstructive symptoms after transurethral prostatectomy (6 months later), 113 (25.9%) were not at 1 month. Compared to 324 patients with early improvement (74.1%), those without improvement at 1 month were characterized by older age (p < 0.01), greater prevalence of preoperative incontinence (p < 0.05), retention (p < 0.01), greater residual rate (p < 0.05), a less compliant bladder (p < 0.01) and a higher positive rate of vesical denervation supersensitivity (p < 0.05). Cystometrographic findings, however, had no relevance to late (6 months) outcome of voiding difficulty. On the other hand, postoperative incontinence was noted in 100 patients (22.9%) at 1 month after transurethral prostatectomy, with the majority having episodes similar to those experienced preoperatively (70.0%) as well as detrusor instability (87.0%). They also were older (p < 0.01), and had a less compliant bladder (p < 0.01) and a higher positive rate of vesical denervation supersensitivity (p < 0.01) than did continent patients. Only 18 elderly patients (4.1%) remained incontinent 6 months later, all with a less compliant (p < 0.01) and more unstable (p < 0.01) bladder initially. The genesis of this detrusor dysfunction was believed to be aging in male patients, in whom BPH evolves and progresses. In conclusion, preoperative cystometrography in patients with BPH is valuable in that it correlated well with the clinical features and it can predict to some extent the outcome of obstructive symptoms and urinary incontinence after transurethral prostatectomy.
The Journal of Urology | 1989
Tomohiko Koyanagi; Hajime Morita; Toshiaki Gotoh; Katsuya Nonomura; Masaki Togashi; Masami Nantani
Experience in the detection of absent vesicoureteral reflux with bethanechol-aided voiding cystourethrography is presented. The detection rate with conventional contrast-enhanced voiding cystourethrography among 9 study subjects, in whom vesicoureteral reflux otherwise was highly suspected from accompanying clinical, urographic and endoscopic features, and in whom it was absent contralaterally or bilaterally, was improved from 33 per cent (only 3 of 9 patients were positive for reflux) to 100 per cent (all 9 were proved to have vesicoureteral reflux) after bethanechol stimulation. Some representative cases are presented and the mechanisms of inducing vesicoureteral reflux with bethanechol are discussed as well as its clinical relevance. Bethanechol-aided voiding cystourethrography is suggested as a highly sensitive method to detect absent vesicoureteral reflux.
Diagnostic and Therapeutic Endoscopy | 1996
Hidehiro Kakizaki; Katsuya Nonomura; Tomohiko Koyanagi; Masami Nantani; Kotaro Taniguchi; Tadashi Matsuno
Since August 1989, we have seen 4 patients with leukoplakia of the renal pelvis associated with a longstanding renal stone. In 2 of them, excretory or retrograde pyelography revealed multiple filling defects in the left renal pelvis as well as a renal stone, although urine cytological examination was negative. One of the other 2 patients underwent extracorporeal shock wave lithotripsy (ESWL) for the renal stone, but this was not followed by the passage of stone fragments. The renal stone in the remaining patient was associated with staghorn calculi. For stone extraction as well as endoscopic evaluation of the intrapelvic lesion, percutaneous nephroscopy was performed. A small to large amount of tissue-like white debris in sheets characteristic of leukoplakia was found in the renal pelvis with stones embedded in it and was removed directly by forceps or suction and then by irrigating with saline. We propose that 1) the endourological approach should be recommended for patients with renal pelvic lesions associated with longstanding renal stones or for patients who show difficulty in passing stone fragments after ESWL and 2) this entity of leukoplakia should be kept in mind for the differential diagnosis of renal pelvic lesions associated with renal stones.
Contributions To Nephrology | 1990
Kazuo Itoh; Kotarou Taniguchi; Masami Nantani; Katsuya Nonomura; Masayori Furudate; Tomohiko Koyanagi
The Japanese Journal of Urology | 1984
Katsuya Nonomura; Kaori Imanaka; Masami Nantani; Tomohiko Koyanagi; Kazuo Ito
The Japanese Journal of Urology | 1986
Masaki Togashi; Haruo Seki; Masami Nantani; Koutarou Taniguchi; Shouichirou Nakanishi; Shigeo Sakashita; Akio Maru; Tomohiko Koyanagi; Keisyuu Yasuda; Tatsuzou Tanabe
The Japanese Journal of Urology | 1994
Hirokazu Shinojima; Hidehiro Kakizaki; Katsuya Nonomura; Tetsufumi Yamashita; Kouichi Kanagawa; Tomohiko Koyanagi; Masami Nantani; Tadashi Matsuno
The Japanese Journal of Urology | 1993
Kaname Ameda; Masami Nantani; Kotaro Taniguchi; Tadashi Matsuno; Tomohiko Koyanagi
The Journal of Urology | 1987
Katsuya Nonomura; Tomohiko Koyanagi; Naoyuki Sakakibara; Masami Nantani
The Journal of Urology | 1987
Katsuya Nonomura; Tomohiko Koyanagi; Naoyuki Sakakibara; Masami Nantani