Kouhei Kawaguchi

The response of the detrusor muscle to acetylcholine in patients with infravesical obstruction

SummaryWe previously examined the effects of overdistension on the neuromuscular system of canine urinary bladders and reported that bladder overdistension led to nerve degeneration and subsequent supersensitivity through a decrease of blood supply to the bladder. We have accordingly in this study evaluated these changes in human subjects with infravesical obstruction. The responses to acetylcholine of bladder strips obtained from patients with detrusor instability were not significantly different from those of bladder strips from patients without detrusor instability, but the dose-response curve of these groups showed a shift to the right compared to that of the unobstructed control patients. As compared with the response of bladder strips in patients without an episode of retention, the response in patients who received prostatectomy within 30 days demonstrated no significant difference, although in patients who received prostatectomy after more than 30 days there was a statistical difference. These results indicated a significant decrease in sensitivity of the detrusor muscle in patients with infravesical obstruction and suggest that bladder overdistension caused by infravesical obstruction may lead to supersensitivity of the detrusor muscle secondary to denervation.

The Influence of Prostatic Urethral Anesthesia in Overactive Detrusor in Patients with Benign Prostatic Hyperplasia

We examined the effects of prostatic urethral anesthesia on cystometrography in benign prostatic hyperplasia (BPH) patients with or without neurological disorders. Although cystometrography after anesthesia showed no disappearance of involuntary detrusor contraction, it did demonstrate significant increases in first sensation volume and maximum cystometric capacity in BPH patients without neurological diseases, as well as BPH patients with a history but no physical evidence of neurological disease. Furthermore, the bladder might be augmented more efficaciously in patients with involuntary detrusor contractions. No significant differences were found in first sensation volume or maximum cystometric capacity before and after anesthesia in patients without infravesical obstruction who had documented neurological disease with physical evidence. Our results demonstrated that prostatic urethral anesthesia can be used preoperatively in patients with infravesical obstruction to discriminate whether involuntary detrusor contractions are due to infravesical obstruction or to neurological disease.

Case of leiomyosarcoma of the renal pelvis

Abstract  A 54‐year‐old man presented at the Mibayashi clinic with bowel discomfort. Ultrasonography showed a left renal mass and the patient was referred to Noto General Hospital for urological evaluation. Results of the physical examination were unremarkable, but computed tomography and magnetic resonance imaging demonstrated a large tumor in the middle of the left kidney. The patient underwent left nephrectomy. On hemisection of the kidney, a firm tumor, measuring 8 × 7.5 cm, was seen occupying the renal pelvis. The histological diagnosis was leiomyosarcoma arising from the right renal pelvis. No treatment was provided after surgery and no recurrence was observed 6 months postoperatively.

The influence of pelvic nerve transection on the neuromuscular system of the canine urinary bladder.

SummaryWe previously reported that bladder overdistension led to denervation and subsequent supersensitivity of the detrusor muscle to acctylcholine. Therefore, to exclude the influence of bladder overdistension, we produced a low-pressure bladder in female mongrel dogs using an indwelling urethral catheter, and performed pelvic neurectomy (decentralization). We examined the effects of decentralization on the neuromuscular system of the bladder. The contraction response levels of bladder strips in dogs 1 and 2 weeks after neurectomy was low, and significantly different from that of bladder strips in the control group. The doseresponse curves of dogs 4 and 8 weeks after neurectomy showed a shift to the left when compared to those of the control group, indicating a significant increase in sensitivity of the bladder strips. Many cholinergic terminal and varicosity profiles had a normal ultrastructure in all of the groups subjected to neurectomy, while some had degenerating profiles representing clear axoplasm without any recognizable organelles. Microphotographs of bladders obtained from dogs with spontaneous catheter loss showed degenerating axons, which were observed more frequently than in bladders kept empty with indwelling urethral catheters. Micturition in the dogs with spontaneous catheter loss was achieved by overflow incontinence without catheterization. These findings suggest that post-synaptic nerve degeneration may be augmented by impairment of micturition, followed by decentralization. Our observations also suggest that post-synaptic nerve degeneration (denervation) plays an important role in the increased sensitivity of the detrusor muscle to acetylcholine in the parasympathetically decentralized urinary bladder, whether denervation is due to trans-synaptic degeneration or impairment of micturition.

Methotrexate, vinblastine, doxorubicin, and cisplatin for advanced urothelial cancer

SummaryA series of 31 patients with advanced urothelial cancer were treated with combination chemotherapy consisting of 1–4 cycles of methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC). Of the 31 patients, 29 had measurable and evaluable lesions. A complete remission was achieved by 4 of these 29 patients (14%) for 1–46 months. A partial remission was observed in 14 of the 29 patients (48%) for 1–9 months. Whereas bony and hepatic metastatic lesions did not respond, some nodal (7/12), pulmonary (4/8), and pelvic lesions (2/3) as well as primary bladder tumors (4/6) and a tumor marker (1/2) responded. Complete tumor remission was observed in nodal (2/12) and pulmonary (1/8) metastatic lesions, in invasive lesions to the prostate and seminal vesicle (1/1), and in primary lesions in the bladder (2/6), ureter (1/1), and urethra (1/1). Two of three patients with non-transitional cell tumors attained a partial remission for 1–7 months. Complete remission of the pulmonary lesions was obtained in a case of squamous cell cancer of the bladder with pulmonary metastases. The toxicity of this regimen was generally tolerable and included moderate to severe myelosuppression, mild to moderate nausea and vomiting, renal toxicity, and mucositis. These results suggest that the M-VAC regimen holds promise for the treatment of advanced metastatic transitional cell cancer as well as nontransitional cell cancer of the urothelium.