Kazuhiro Ishizaka

Failure of the Expression of Phospholipid Hydroperoxide Glutathione Peroxidase in the Spermatozoa of Human Infertile Males

Abstract Phospholipid hydroperoxide glutathione peroxidase (PHGPx) was intensely expressed in mitochondria in the midpiece of human spermatozoa by immunostaining with anti-PHGPx monoclonal antibodies. The PHGPx not only reduced phospholipid hydroperoxide but also scavenged hydrogen peroxide in human spermatozoa. We found a dramatic decrease in the level of expression of PHGPx in the spermatozoa of some infertile males by immunoblotting with anti-PHGPx monoclonal antibodies. These individuals accounted for about 10% of the group of 73 infertile males that we examined. All seven patients with PHGPx-defective spermatozoa were classified as suffering from oligoasthenozoospermia, a defect in which both the number and the motility of spermatozoa are significantly below normal. Males with PHGPx-defective spermatozoa accounted for 26% of the 27 infertile males with oligoasthenozoospermia. No defects in expression of PHGPx in spermatozoa were observed in 31 fertile volunteers. After a 3-h incubation, the relative number of motile spermatozoa with low-level expression of PHGPx was significantly lower than that of spermatozoa with normal expression of PHGPx. The PHGPx-defective spermatozoa failed to incorporate rhodamine 123, revealing a loss of mitochondrial membrane potential. Ultrastructual analysis of mitochondria by electron microscopy demonstrated that the morphology of mitochondria in PHGPx-defective spermatozoa was abnormal. The results suggest that failure of the expression of mitochondrial PHGPx in spermatozoa might be one of the causes of oligoasthenozoospermia in infertile men.

Depletion of selenoprotein GPx4 in spermatocytes causes male infertility in mice.

Phospholipid hydroperoxide glutathione peroxidase (GPx4) is an intracellular antioxidant enzyme that directly reduces peroxidized phospholipids. GPx4 is strongly expressed in the mitochondria of testis and spermatozoa. We previously found a significant decrease in the expression of GPx4 in spermatozoa from 30% of infertile human males diagnosed with oligoasthenozoospermia (Imai, H., Suzuki, K., Ishizaka, K., Ichinose, S., Oshima, H., Okayasu, I., Emoto, K., Umeda, M., and Nakagawa, Y. (2001) Biol. Reprod. 64, 674–683). To clarify whether defective GPx4 in spermatocytes causes male infertility, we established spermatocyte-specific GPx4 knock-out mice using a Cre-loxP system. All the spermatocyte-specific GPx4 knock-out male mice were found to be infertile despite normal plug formation after mating and displayed a significant decrease in the number of spermatozoa. Isolated epididymal GPx4-null spermatozoa could not fertilize oocytes in vitro. These spermatozoa showed significant reductions of forward motility and the mitochondrial membrane potential. These impairments were accompanied by the structural abnormality, such as a hairpin-like flagella bend at the midpiece and swelling of mitochondria in the spermatozoa. These results demonstrate that the depletion of GPx4 in spermatocytes causes severe abnormalities in spermatozoa. This may be one of the causes of male infertility in mice and humans.

Preventive effect of risedronate on bone loss in men receiving androgen‐deprivation therapy for prostate cancer

Aim:  Androgen‐deprivation therapy for prostate cancer decreases bone mineral density and increases the risk of fracture. The effect of risedronate, a potent third‐generation oral bisphosphonate, on bone loss during androgen deprivation therapy was investigated.

Significance of bladder neck involvement on progression in superficial bladder cancer.

Objectives: To determine the significance of bladder neck involvement in predicting disease progression in superficial (stage Ta and T1) transitional cell carcinoma (TCC) of the urinary bladder. Patients and Methods: A series of 277 patients with newly diagnosed superficial TCCs of the bladder was reviewed, and disease progression (to T2 or worse) was considered. The significance of several risk factors including bladder neck involvement was assessed in univariate and multivariate analysis. Results: Progression occurred in 28 (10.1%) of 277 patients during a median follow-up period of 7.7 years. Nineteen died of bladder cancer. The following variables were found to be statistically significant at the univariate analysis (p < 0.05): irritative symptoms, urine cytology, tumor stage, involvement of the bladder neck, and tumor grade. Indeed, only involvement of the bladder neck, tumor stage, and grade retained their value as independent factors for progression at multivariate analysis. Patients were divided into three groups according to the number of independent risk factors they had. Groups having none, one, and two or three risk factors included 129, 99, and 49 patients with 5-year progression rates of 0.8, 4.6 and 27.5%, and 15-year rates of 4.0, 20.1 and 42.7%, respectively. Conclusion: Involvement of the bladder neck is a significant and independent risk factor for progression of superficial TCCs in addition to the histologic grade and stage. The combination of these three risk factors offers better prediction of progression in an individual patient.

Endoscopic minilaparotomy radical nephrectomy for chronic dialysis patients

Abstract Background : To assess the feasibility of laparoscope‐guided minilaparotomy (endoscopic minilaparotomy) for renal cell carcinoma in patients on chronic dialysis.

Effects of Prostaglandins E1 E2 and F2α on Contractility and cAMP and cGMP Contents in Lower Urinary Tract Smooth Muscle

Prostaglandin (PG) E1, E2 and F2 alpha contracted smooth muscle strips from male adult rabbit urinary bladder. Contractile responses to each PG were significantly greater in urinary bladder body than in urinary bladder base. The magnitude of contractile response to each PG was F2 alpha > E2 > E1 in both of the bladder body and the bladder base. These contractions were almost completely eliminated by a calcium entry blocker, verapamil but not by atropine, phentolamine, propranolol or tetrodotoxin. PG E1 and E2 significantly relaxed the male rabbit urethral smooth muscle strips, whereas PG F2 alpha contracted the urethral smooth muscle strips. Cyclic adenosine monophosphate (cAMP) but not cyclic guanosine monophosphate (cGMP) increased significantly after administration of PG E1 or E2 in the urethral muscle strip. These results suggest that the regional differences in the magnitude of contractile responses to PG E1, E2 and F2 alpha between the bladder dome and the base and also suggest the contractile differences of PG E1 and E2 for the urinary bladder and the urethra; contractions for bladder and relaxations for urethra. These results also demonstrate that contractions induced by PG E1, E2 and F2 alpha in urinary bladder smooth muscles and by PG F2 alpha in urethral smooth muscles are mainly mediated by calcium influx and that relaxations induced by PG E1 and E2 in urethral smooth muscles are mediated by cAMP but not by cGMP.

Suppression of spermatogenesis in ipsilateral and contralateral testicular tissues in patients with seminoma by human chorionic gonadotropin beta subunit

OBJECTIVES The pathologic complexity of the testicular tumor makes it difficult to demonstrate exactly the relationship between the impaired spermatogenesis in patients with a testicular tumor and the serum level of the human chorionic gonadotropin beta subunit (beta-hCG). Therefore, we performed quantitative evaluation of spermatogenesis in ipsilateral and contralateral testicular tissues of seminoma to simplify the relation pathologically and endocrinologically and to demonstrate the exact correlation between spermatogenesis and serum beta-hCG levels. METHODS Fifty-three biopsy specimens from ipsilateral and contralateral testicular tissues of seminoma were analyzed histologically. The quantitative evaluation of spermatogenesis was performed by the mean Johnsens score count (MJSC). Beta-hCG expression in seminoma was examined immunohistochemically. Serum beta-hCG, testosterone, estradiol, luteinizing hormone, and follicle-stimulating hormone levels were analyzed before orchiectomy. RESULTS A significant linear relationship (r = -0.82; P <0.005) was found between the serum level of beta-hCG and the MJSC in contralateral testicular tissues but not in ipsilateral ones, although the suppression of spermatogenesis was observed in both sides without suppression of luteinizing hormone and/or follicle-stimulating hormone production. CONCLUSIONS A clearcut fall in the MJSC with an associated rise in the serum level of beta-hCG was demonstrated in the contralateral testicular tissues but not in the ipsilateral ones of seminoma. It seems most likely that serum beta-hCG suppresses spermatogenesis in both ipsilateral and contralateral testicular tissues without the suppression occurring through the hypothalamus-pituitary-gonadal system, and also that some less well recognized factors affect spermatogenesis, making the relation between serum beta-hCG and MJSC obscure in ipsilateral testicular tissues.

Endogenous asymmetrical dimethylarginine and hypertension associated with puromycin nephrosis in the rat

1 The present experiments were designed to investigate the role of asymmetrical NG,NG‐dimethyl‐L‐arginine (ADMA) in causing hypertension associated with the focal and segmental glomerulosclerosis (FSGS) produced by a single bolus of puromycin aminonucleoside (PAN) and successive injection of protamine for 7 days in rats which had undergone unilateral nephrectomy. 2 After the unilateral nephrectomy, and administering PAN and protamine, histological examinations of the kidney revealed a typical FSGS, that is, evident abnormalities including segmental mesangial proliferation, obliteration of glomerular capillary lumens and adhesions between the glomerulus and Bowmans capsule could be observed. Changes in the glomerular epithelial cells consisted of the swelling with bleb formation. 3 In the FSGS rats, urine volume and urinary protein were significantly (P<0.05 and P<0.005) increased throughout 4‐week experimental period, while the creatinine clearance was significantly (P<0.005) and transiently decreased, and recovered 4 weeks later. These changes were associated with the sustained elevation of the systolic blood pressure. 4 ADMA levels in aortic endothelial cells, plasma and urine were significantly (P<0.05 and P<0.005) increased in the FSGS rats, but the level in the kidney remained unchanged. 5 The basal level and net production of cyclic GMP in the aortic vessel wall with endothelium when stimulated by norepinephrine and acetylcholine were significantly (P<0.05 and P<0.01) attenuated in the FSGS rats. 6 There were significant and positive correlations between systolic blood pressure (y) and ADMA levels (x) in endothelial cells (y=4.43x+122.2, r=0.979, P<0.0001), plasma (y=0.10x+71.9, r=0.921, P<0.001) and urine (y=0.48x+126.9, r=0.699, P<0.005), but not significant in the kidney (y=0.06x+102.7, r=0.252, NS). 7 These findings suggest that ADMA as an endogenous inhibitor of NO synthesis may play an important role for the pathogenesis in the hypertension associated with the experimental FSGS in the rat.

SEX DIFFERENCES IN FUNCTION AND DISTRIBUTION OF beta-ADRENOCEPTORS IN RABBIT URINARY BLADDER

PURPOSE To examine whether there are sex-related differences in urinary bladder function, we evaluated the function and distribution of beta-adrenoceptor in the male and female rabbit urinary bladder. MATERIALS AND METHODS Ten male and ten female rabbits were studied. The function and distribution of beta-adrenoceptors were studied by measuring changes in contractile forces from isoproterenol, a beta-adrenoceptor agonist, and forskolin, an adenylate cyclase activator, and by measuring beta-adrenoceptor densities using radioligand receptor binding techniques. RESULTS Isoproterenol caused significantly greater relaxation in female trigonal muscles than in male trigonal muscles. It caused similar relaxation responses in the male and female detrusors. The Bmax values for [3H]dihydroalprenolol (DHA) binding in trigonal muscles were significantly higher in the female than in the male, whereas Bmax values for [3H]DHA binding in the male and the female detrusor were similar. In contrast, forskolin caused similarly marked relaxations in the male and the female detrusor and trigonal muscles. CONCLUSION These findings demonstrate that there are sex-related differences in the function and the distribution of beta-adrenoceptors in rabbit trigonal smooth muscles.

Clear cell adenocarcinoma of the urinary bladder inducing acute renal failure

We report a case of clear cell adenocarcinoma of the urinary bladder. A 59‐year‐old male was referred to our hospital complaining of oliguria, left lower abdominal pain and loss of appetite. Ultrasonography revealed bilateral hydroureteronephrosis and obstructions at the ureterovesical junction. Magnetic resonance imaging demonstrated an invasive irregular tumor located in the posterior wall of the urinary bladder and urinary infiltration to the left retroperitoneal space.The clinical diagnosis was acute post renal failure due to bilateral ureteral obstructions from an invasive bladder tumor. After we performed bilateral percutaneous nephrostomy, the patient underwent trans urethral biopsy of the bladder tumor, which showed clear cell adenocarcinoma extending from the submucosa to the muscular layer, histopathologically. The patient died of metastatic disease 8 months after diagnosis. To our knowledge, the present case is the 23rd to be reported and demonstrates the shortest survival period in the related literature.