Yoshimasa Yanai

Role of interstitial cells and gap junctions in the transmission of spontaneous Ca2+ signals in detrusor smooth muscles of the guinea-pig urinary bladder

To investigate mechanisms underlying the transmission of spontaneous Ca2+ signals in the bladder, changes in intracellular concentrations of Ca2+ ([Ca2+]i) were visualized in isolated detrusor smooth muscle bundles of the guinea‐pig urinary bladder loaded with a fluorescent Ca2+ indicator, fura‐PE3 or fluo‐4. Spontaneous increases in [Ca2+]i (Ca2+ transients) preferentially originated along the boundary of muscle bundles and then spread to the other boundary (Ca2+ waves). The synchronicity of Ca2+ waves across the bundles was disrupted by 18β‐glycyrrhetinic acid (18β‐GA, 40 μm), carbenoxolone (30 μm) or 2‐aminoethoxydiphenylborate (2‐APB, 50–100 μm), while CPA (10 μm), ryanodine (100 μm), xestospongin C (3 μm) and U‐73122 (10 μm) had no effect. Intracellular recordings using two independent microelectrodes demonstrated that 2‐APB (100 μm) blocked electrical coupling between detrusor smooth muscle cells. Nifedipine (10 μm) but not nominal Ca2+‐free solution diminished the synchronicity of Ca2+ waves before preventing their generation. Staining for c‐kit identified interstitial cells (IC) located along both boundaries of muscle bundles. IC were also scattered amongst smooth muscle cells and were more dominantly distributed in connective tissue between muscle bundles. IC generated nifedipine‐resistant spontaneous Ca2+ transients, which occurred independently of those of smooth muscles. In conclusion, the propagation of Ca2+ transients in the bladder appears to be exclusively mediated by the spread of action potentials through gap junctions being facilitated by the regenerative nature of L‐type Ca2+ channels, without significant contribution of intracellular Ca2+ stores. IC in the bladder may modulate the transmission of Ca2+ transients originating from smooth muscle cells rather than being the pacemaker of spontaneous activity.

Interaction between spontaneous and neurally mediated regulation of smooth muscle tone in the rabbit corpus cavernosum

Interaction between spontaneous and neurally mediated regulation of tone in the corpus cavernosum smooth muscle (CCSM) of the rabbit was investigated. Changes in isometric muscle tension, intracellular Ca2+ concentration ([Ca2+]i) and membrane potential were recorded. CCSM developed spontaneous contractions, transient increases in [Ca2+]i (Ca2+ transients) and depolarizations. This spontaneous activity was abolished by blocking L‐type Ca2+ channels (nicardipine, 1 μm), sarcoplasmic reticulum Ca2+ pump activity (cyclopiazonic acid, 10 μm), Ca2+‐activated Cl− channels (niflumic acid, 10 μm) or cyclooxygenase‐2 (COX‐2; NS‐398, 1 μm). Transmural nerve stimulation initiated either α‐adrenergic contractions or nitrergic relaxations of CCSM depending on the level of muscle tone. NS‐398 suppressed nerve‐evoked contractions by about 70% but caused only a 40% reduction in the corresponding Ca2+ transient. Blocking nitric oxide synthase with Nω‐nitro‐l‐arginine (LNA, 100 μm) reinforced nerve‐evoked Ca2+ transients by about 150%, whilst increasing the corresponding Ca2+ transients by only 20%. In CCSM preparations that had been pre‐contracted with either noradrenaline (0.3 μm) or prostaglandin F2α (0.1 μm), nerve stimulation inhibited about 70% of the contraction and caused only a 20% decrease in [Ca2+]i. Fluorescent immunohistochemistry with COX‐2 antibodies and the reverse transcriptase‐polymerase chain reaction (RT‐PCR) method showed that the enzyme and its mRNA were highly expressed in the CCSM. These results suggest that spontaneously produced prostaglandins (PGs) not only contribute to the generation of spontaneous contractions but also facilitate nerve‐evoked contractions. Conversely, spontaneously released nitric oxide (NO) suppresses excitation. Thus, interaction between spontaneous and neurally mediated regulation of CCSM tone may be fundamental to maintaining the muscle contractility. In addition, both PGs and NO appear to alter CCSM tone with only small changes in [Ca2+]i.

The role of Ni2+-sensitive T-type Ca2+ channels in the regulation of spontaneous excitation in detrusor smooth muscles of the guinea-pig bladder

To explore the role of Ni2+‐sensitive T‐type Ca2+ channels in the generation of spontaneous excitation of detrusor smooth muscles.

Cyclooxygenase-2 protects germ cells against spermatogenesis disturbance in experimental cryptorchidism model mice.

The role of cyclooxygenases (COX) in the male reproductive organ remains unclear. However, there are some reports suggesting that COX-2 might have an effect on spermatogenesis or steroidogenesis. In this study, we examined whether COX-2 was induced in impaired testes, and we also investigated the possible role of COX in the testes using experimental cryptorchidism model mice. Five-week-old male mice underwent an operation to induce unilateral cryptorchidism via an abdominal incision and suturing of the left testes to the lateral abdominal wall, and they were then divided into 3 groups: 1) experimental cryptorchidism plus SC560 (selective COX-1 inhibitor) administration; 2) experimental cryptorchidism plus NS398 (selective COX-2 inhibitor) administration; 3) and experimental cryptorchidism alone. The expression levels of COX-1 and COX-2 were determined by immunohistologic staining and quantitative reverse transcription-polymerase chain reaction (RT-PCR). The influence of COX inhibitors on the testes was assessed by measuring the concentration of serum testosterone and evaluating the seminiferous tubules according to the Johnsen score. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining was also performed to detect apoptosis in the testes. Immunohistologic staining and RT-PCR revealed that the expression of COX-2 was increased in the experimental cryptorchid testes (groups 1-3). The concentration of serum testosterone was significantly lower in group 2 at 5 weeks after surgery than in the other groups. The Johnsen score of the cryptorchid testes in group 2 was significantly lower than those in other groups at 5 weeks after surgery. TUNEL staining revealed that the number of apoptotic cells was significantly increased in group 2 compared with the other groups. However, the COX-1 inhibitor did not appear to affect spermatogenesis in the experimental cryptorchid testes. These results suggest that the COX-2 inhibitor provoked testicular damage in experimental cryptorchidism by inducing germ cell apoptosis. The expression of COX-2 might be induced to protect germ cells from heat stress caused by experimental cryptorchidism.

Heterogeneous CPA sensitivity of spontaneous excitation in smooth muscle of the rabbit urethra

1 To investigate the role of intracellular Ca stores in generating spontaneous excitation of the urethra, the effects of cyclopiazonic acid (CPA) on spontaneous contractions, transient increases in intracellular calcium concentration ([Ca2+]i; Ca transients) and depolarizations were examined in smooth muscles of the rabbit urethra. 2 In about 90% of circular smooth muscle (CSM) preparations, CPA (10 μM) increased the amplitude of spontaneous contractions by about 180% and reduced their frequency to some 25% of control values (CPA‐resistant), while it readily abolished the contractions in the remaining preparations. 3 In about 70% of CSM preparations, CPA prevented the generation of spontaneous depolarizations termed slow waves, but increased their amplitude and duration in the remainder. CPA also prevented the generation of spontaneous Ca transients in about 40% of CSM preparations, while increasing their amplitude and duration in the remaining preparations. In CPA‐resistant preparations that had been exposed to nicardipine (1 μM), subsequent CPA invariably abolished residual spontaneous depolarizations or Ca transients. CPA abolished caffeine‐induced Ca transients in Ca‐free solutions, suggesting that it effectively depleted intracellular Ca stores. 4 Longitudinal smooth muscles generated spontaneous action potentials, which had a shape distinct from that of slow waves in CSM. Spontaneous action potentials were abolished by nicardipine but not CPA. 5 Transmural nerve stimulation increased the frequency of Ca transients to give a sustained rise in [Ca2+]i, but inhibited their generation after blocking α‐adrenoceptors with phentolamine (1 μM). These nerve‐evoked responses were preserved in preparations that had been exposed to CPA. Similarly, both in control and CPA‐treated CSM preparations, spontaneous Ca transients were accelerated by noradrenaline (NAd, 1 μM) and were suppressed by 3‐morpholino‐sydnonimine (SIN‐1, 10 μM), a nitric oxide (NO) donor. 6 In conclusion, CSM of the urethra generates spontaneous activity, which depends on Ca release from intracellular Ca stores. However, after blocking this primary pacemaking mechanism, L‐type Ca channel‐dependent action potentials may drive CSM. Irrespective of the origin of pacemaking, neurally‐released NAd and NO are capable of modulating spontaneous excitation.

Effect of microsurgical repair of the varicocele on testicular function in adolescence and adulthood

Objective:  Many reports on varicoceles suggest improved spermatic findings and increased pregnancy rates after correction of these lesions. Early repair during adolescence has been advocated, since clinically apparent varicoceles may affect testicular volume and sperm production in the future. We examined the efficacy of microsurgical varicocelectomy, and aimed to establish predictive parameters useful for ascertaining whether varicocele repair provides any benefits in adolescents and adults.

Loxoprofen sodium treatment for elderly men with refractory nocturia: effect on night-time urine production.

Abstract:  We evaluated the efficacy of loxoprofen sodium for refractory nocturia. Twelve men (mean age, 75.1 ± 5.7) with nocturia were enrolled in this study. All patients received 60 mg loxoprofen sodium prior to sleeping at night for 14 days. Nine of 12 patients (75%) felt more satisfaction than previous treatments. Patients were grouped into a loxoprofen sodium‐effective (n = 7) and ineffective groups (n = 5) based on the results of the frequency‐volume chart. In the effective group, interestingly, night‐time urine volume showed significant reduction (P < 0.05). On the other hand, the average single voided volume at night and 24‐h urine volume showed no significant change. There was a statistically significant difference in the night‐time urine volume after treatment between groups (P < 0.01). Loxoprofen sodium is an effective treatment for some patients with refractory nocturia. The main effect mechanism of loxoprofen sodium may involve the reduction of night‐time urine production.

Azoospermia with Klippel-Feil anomaly.

Abstract:  We present a case of azoospermia with Klippel‐Feil anomaly. Klippel‐Feil anomaly is characterized by the fusion of two or more cervical vertebrae and a short neck, limitation of head movement, and low posterior hairline. The association of this anomaly with MURCS (Müllerian‐duct asplasia, renal agenesis, and cervical somite dysplasia) is traditionally regarded as being limited to females, but it has been hypothesized that men displaying the combination of azoospermia, segmentation abnormalities of the cervicothoracic spine, and renal anomalies have a male analog of MURCS. Here we describe the first case of MURCS in a male in whom testicular sperm extraction was carried out.

Feasibility of metronomic chemotherapy with tegafur-uracil, cisplatin, and dexamethasone for docetaxel-refractory prostate cancer

Objectives: To evaluate the efficacy of tegafur–uracil (UFT), a prodrug of 5-fluorouracil, plus cisplatin and dexamethasone in patients with docetaxel-refractory prostate cancers. Methods: Twenty-five patients with docetaxel-refractory prostate cancer were administered oral UFT plus intravenous cisplatin (UFT-P therapy) and dexamethasone. Treatment responses were assessed monthly via prostate-specific antigen (PSA) level measurements. Treatment-related adverse events and overall survival were also assessed. Results: UFT-P therapy resulted in decreased PSA levels in 14 (56%) patients and increased PSA levels in 11 (44%). In patients with increased PSA levels, 7 (64%) of the 11 patients displayed decreased PSA doubling times. The UFT-P therapy response rate was 84% (21/25 patients). Imaging studies revealed that tumor shrinkage during UFT-P therapy occurred in 1 patient in whom bilateral hydronephrosis caused by lymph node metastasis improved. The median survival time from docetaxel initiation was 36 months. In UFT-P-treated patients, the median PSA progression and overall survival times were 6 and 14 months, respectively. UFT-P treatment-related adverse events were mild diarrhea, general fatigue, and anorexia. Treatment was not discontinued for any of the patients. UFT-P therapy did not cause serious hepatic or renal dysfunction or pancytopenia. Conclusions: UFT-P therapy is a safe and effective treatment for patients with docetaxel-refractory prostate cancer, although large-scale, multicenter, prospective studies are needed to validate these findings.

CYCLOOXYGENASE-2 APPEARS TO BE INDUCED IN THE TESTES OF EXPERIMENTAL CRYPTORCHIDISM IN ORDER TO REDUCE THE APOPTOSIS OF GERM CELLS AND MAY HAVE A KEY ROLE ON PROTECTION OF GERM CELLS FROM HEAT-STRESS

INTRODUCTION AND OBJECTIVES: The roles of Cyclooxygenases (COXs) in the male reproductive tract remain unclear. However, there are some reports that suggest the COX-2 might have effect on spermatogenesis or steroidogenesis. In this study, we examined whether COX-2 is induced in impaired testes and also investigated the possible role of COXs in the testes using experimental cryptorchidism model mice. METHODS: Five-week-old male mice underwent an operation to induce unilateral cryptorchidism by an abdominal incision and suturing of the left testes to the lateral abdominal wall, and were then divided into three groups: (1) experimental cryptorchidism plus SC560 (selective COX-1 inhibitor) administration; (2) experimental cryptorchidism plus NS398 (selective COX-2 inhibitor) administration; (3) experimental cryptorchidism alone. The expressions of COX-1 and COX-2 were determined by immunohistological staining and quantitative reverse transcriptional polymerase chain reaction (RT-PCR). The influence of COX inhibitors on the testis was assessed by measuring the concentration of serum testosterone and evaluating the seminiferous tubules according to the Johnsen score (JS). TdT-mediated dUTP-biotin nick end-labeling (TUNEL) staining was also performed to detect apoptosis in the testes. RESULTS: Immunohistological staining and RT-PCR revealed that the expression of COX-2 was increased in the experimental cryptorchidism testes (group 1-3). The concentration of serum testosterone was significantly lower in group 2 at 5 weeks after surgery than that in other groups; however, not in the level of castration. The Johnsen score of cryptorchidism testes in group 2 was significantly lower than that in other groups at 5 weeks after surgery. TUNEL staining revealed that the apoptotic cells were significantly increased in group 2 compared with that in other groups. Meanwhile, COX-1 inhibitor did not appear to affect spermatogenesis in the experimental cryptorchid testes. CONCLUSIONS: These results suggest that COX-2 inhibitor could reinforce testicular damage in the experimental cryptorchidism by inducing germ cell apoptosis. The expression of COX-2 might be induced to protect germ cells from heat stress caused by experimental cryptorchidism.