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Biomedical subjects

I Miyagawa

Publications and source records attributed to I Miyagawa.

At least 19 recordsLinked to original sources
PubMed2002

Cryptorchidism: seasonal variations in Greece do not support the theory of light.

To examine seasonal trends of cryptorchidism in Greece, 583 males with true isolated cryptorchidism were analyzed. All 208 912 live-born boys born during the same period were used as a comparison group. Seasonality by month of birth was evaluated using both Edwards' model with adjusted frequencies and exact theta(i), and Walter-Elwood method with exact theta(i). Both tests resulted in consistent findings. The incidence of cryptorchid births in Greece follows a documented cyclic pattern of simple harmonic type with spring being the season of statistical predominance (peak in March with a second, almost equivalent, peak in May). In contrast, in autumn the incidence of cryptorchid births was considerably lower (trough in September). Given the fact that no significant differences in daylight length are found among seasons in Greece, the detection of a significant seasonal variation suggests that factors other than light are involved in the pathogenesis of cryptorchidism. Low environmental temperature is proposed as a causative factor negatively influencing the maternal hCG profiles and the inguinoscrotal phase of testicular descent. This is further supported by: (i) the similarity of our results to those reported by other European countries of different longitude and geographical width and (ii) our data showing significantly smaller maternal hCG profiles at the 26th week of gestation during winter compared with summer.

Chorionic Gonadotropin↗
PubMed2002

Use of a highly sensitive quantitative telomerase assay in intracytoplasmic sperm injection programmes for the treatment of 47,XXY non-mosaic Klinefelter men.

We evaluated the role of the sensitive quantitative telomerase assay (SQTA) in the management of men with non-mosaic Klinefelter's syndrome (KS). Diagnostic testicular biopsy (DTB) was performed in 24 men with KS. A part of the DTB was stained and the remaining fragment was processed for the SQTA. After 3-18 months, a therapeutic testicular biopsy (TTB) was performed in the same testicle and the recovered specimens were processed to identify spermatozoa. Men with a SQTA outcome equal to 0.00 Units microg-1 protein (n = 7) demonstrated therapeutic testicular biopsy material that was negative for spermatogenic cells. In five men with a SQTA outcome of 8.11-38.03 Units microg-1, the most advanced germ cell was the spermatogonium/primary spermatocyte. In the remaining 12 men, the most advanced spermatogenic cell in the TTB was the spermatozoon. In these men, the SQTA outcome was equal to 25.76-92.68 Units microg-1 protein. Using 39.00 Units microg-1 protein as a cut-off value, the accuracy of the SQTA in identifying men positive for spermatozoa was 91.6%. It appears that the SQTA has a role for identifying non-mosaic KS men who have testicular spermatozoa.

Adult↗
PubMed2001

Bladder dysfunction after acute urinary retention in rats.

PURPOSE: We investigated bladder function in acute urinary retention and subsequent catheterization in rat bladders. MATERIALS AND METHODS: The penile urethra in rats was clamped with a small clip and cystostomy was performed to infuse 3 ml. of saline for inducing acute urinary retention. At 30 minutes after the induction of urinary retention the cystostomy was opened to empty the bladder. In functional studies contractile responses to carbachol were measured in group 1-before, group 2-at 3 ml. of urinary retention, group 3-at 3 ml. of urinary retention exposed for 30 minutes and group 4-30 minutes after catheterization. Moreover, in vivo real-time monitoring of blood flow and vesical pressure were measured in the bladders with a laser Doppler flowmeter and cystometrography, respectively. Malonaldehyde and 4-hydroxyalkenals were measured by colorimetric assay in these groups. RESULTS: In functional studies the mean maximum contractile response value plus or minus standard deviation of carbachol-to-bladder in groups 1 to 4 was 11.8 +/- 1.3, 11.9 +/- 1.7, 9.8 +/- 0.8 and 6.9 +/- 0.7 gm./mm.2, respectively. In real-time monitoring of blood flow and vesical pressure acute urinary retention significantly decreased blood flow and increased vesical pressure, and subsequent catheterization increased blood flow and decreased vesical pressure in the bladders. The concentrations of malonaldehyde and 4-hydroxyalkenals in the bladders in group 4 were significantly higher than in the other groups. CONCLUSIONS: Our data indicate that bladder dysfunction after catheterization is partially caused by free radicals, which have an important role in bladder dysfunction during acute urinary retention.

Acute Disease↗
PubMed2000

Treatment of overactive bladder with modified intravesical oxybutynin chloride.

Intravesical oxybutynin chloride has been reported to be effective for overactive bladder, although sometimes the efficacy does not last long enough. To improve this deficiency, we report the effects of intravesical oxybutynin chloride with hydroxypropylcellulose (modified intravesical oxybutynin). Modified intravesical oxybutynin (5 mg/10 mL, twice a day) was administered to six overactive bladder patients for more than 1 year (two men and four women; average age, 56.5 years) who did not respond to oral anticholinergic agents and electric stimulation. Cystometography (CMG) was performed before, 2 hours, and 1 week after the start of modified intravesical oxybutynin. In addition, plasma levels of oxybutynin and its active metabolite, N-desethyl-oxybutynin (DEOB), were measured by high-performance liquid chromatography before, 1, 2, and 4 hours after the initial treatment of modified intravesical oxybutynin. CMG studies revealed that two of the six patients did not demonstrate uninhibited contractions 1 week after the treatment and that cystocapacity of before, 2 hours, and 1 week after the initial modified intravesical oxybutynin was 141.8+/-15.3, 210.0+/-35.5, and 305.0+/-21.3 mL, respectively. Plasma levels of oxybutynin and DEOB before, 1, 2, and 4 hours after the first instillation of modified intravesical oxybutynin were oxybutynin; not detected, 8.8+/-2.5, 6.8+/-1.1, 3.0+/- 1.0 ng/ml, and DEOB; not detected, 4.2+/-1.3, 6.4+/-1.7, 5.1+/- 1.4 ng/ml, respectively. No side effects were observed in any of the patients. Modified intravesical oxybutynin is an effective and safe therapy option for overactive bladder patients who do not respond to other treatments such as oral anticholinergic agents and electric stimulation.

Administration, Intravesical↗
PubMed2000

Effects of cotinine on sperm motility, membrane function, and fertilizing capacity in vitro.

We evaluated the effect of cotinine on sperm fertilizing capacity in vitro. Human spermatozoa were washed and re-suspended in medium containing albumin and various concentrations of cotinine (0, 100, 200, 400, or 800 ng/ml). After an 8-h incubation period, sperm motility, hypoosmotic swelling test (HOST) outcome, and the percentage of hyperactivated spermatozoa were assayed. Aliquots of spermatozoa were then processed for the zona-free hamster oocyte sperm penetration assay (SPA) or hamster ooplasmic injections. Spermatozoa exposed to concentrations of cotinine equal to 400 or 800 ng/ml demonstrated significantly smaller outcomes for all of the above with the exception of after hamster ooplasmic injections, where high cotinine concentrations did not affect sperm viability or sperm capacity to undergo decondensation and activate hamster oocytes. It appears that cotinine concentrations of 400 or 800 ng/ml exert a detrimental effect on sperm motility, membrane function, and the ability to undergo capacitation. In addition, the current findings suggest that smokers with a high seminal plasma cotinine concentration who participate in assisted reproduction programs may be treated with intracytoplasmic sperm injections (ICSI) rather than conventional in vitro fertilization (IVF) trials.

Animals↗
PubMed2000

Real-time monitoring of nitric oxide in ischemia-reperfusion rat kidney.

In this study we attempted to clarify the release of nitric oxide (NO) and its role in the ischemia-reperfusion rat kidney. After right nephrectomy, male Wistar rats were divided into four groups: one sham operated and three groups who underwent ischemia (30 min) and reperfusion of the left renal artery. Thirty minutes prior to ischemia-reperfusion, two groups were injected intraperitoneally with 10 and 30 mg/kg of NG-nitro-L-arginine methylester (L-NAME). Real-time monitoring of blood flow and NO release in the rat kidney was measured with a laser Doppler flowmeter and an NO-selective electrode, respectively. Serum creatinine and blood urea nitrogen (BUN) levels were measured 1 and 7 days after the induction of ischemia-reperfusion. Clamping of the renal artery decreased blood flow to 1-5% of the basal level measured before clamping. After removal of the clip, the blood flow of the 30 mg/kg L-NAME rats was significantly lower than that of the controls. Immediately following the clipping of the renal artery, NO release rapidly increased. After removing the clip, NO release immediately returned to three-quarters of the basal level. Serum creatinine and BUN levels of the ischemia-reperfusion rats were slightly but not significantly higher and those of 30 mg L-NAME rats were significantly higher than those of the control or ischemia-reperfusion rats 1 day and 7 days after ischemia-reperfusion. Our data suggest that NO acts as a cytoprotective agent in ischemia-reperfusion injury of the rat kidney.

Animals↗
PubMed2000

Influence of sexual stimulation on sperm parameters in semen samples collected via masturbation from normozoospermic men or cryptozoospermic men participating in an assisted reproduction programme.

To evaluate the influence of sexual stimulation via sexually stimulating videotaped visual images (VIM) on sperm function, two semen samples were collected from each of 19 normozoospermic men via masturbation with VIM. Two additional samples were collected from each man via masturbation without VIM. The volume of seminal plasma, total sperm count, sperm motility, percentage of morphologically normal spermatozoa, outcome of hypo-osmotic swelling test and zona-free hamster oocyte sperm penetration assay, and markers of the secretory function of prostate were significantly larger in semen samples collected via masturbation with VIM than masturbation without VIM. The improved sperm parameters in the samples collected via masturbation with VIM may reflect an enhanced prostatic secretory function and increased loading of the vas deferens at that time. In a similar protocol, two semen samples were collected via masturbation with VIM from each of 22 non-obstructed azoospermic men. Semen samples from these men had been occasionally positive in the past for a very small number of spermatozoa (cryptozoospermic men). Two additional samples were collected from each cryptozoospermic man via masturbation without VIM. The volume of seminal plasma, total sperm count, sperm motility, and a marker of the secretory function of prostate were significantly larger in semen samples collected via masturbation with VIM. Fourteen out of the 22 men were negative for spermatozoa in both samples collected via masturbation without VIM. These men demonstrated spermatozoa in both samples collected via masturbation with VIM. Six men with immotile spermatozoa in both samples collected via masturbation without VIM exposed motile spermatozoa in both samples collected via masturbation with VIM. High sexual stimulation during masturbation with VIM results in recovery of spermatozoa of greater fertilizing potential both in normozoospermic and cryptozoospermic men. The appearance of spermatozoa after masturbation with VIM in the vast majority of cryptozoospermic men is of clinical significance in programmes applying intracytoplasmic sperm injections for the management of severe male infertility and obviates the need for testicular biopsy.

Biomarkers↗
PubMed2000

Results of questionnaires regarding video recordings of benign prostatic obstruction by flexible cystourethroscopy responded to by urologists.

OBJECTIVE: To evaluate the reliability of subjective diagnoses of benign prostatic obstruction (BPO) using flexible cystourethroscopy as compared to the actual degree of bladder outlet obstruction as measured by a pressure-flow study (PFS), and to investigate the difference of subjective diagnoses among different urologists. METHODS: A standardized PFS was done in 33 BPO patients. The degree of BPO (0 approximately VI) was determined by linear PURR. Flexible cystourethroscopy was also performed in order to evaluate the BPO by video recording. Nine urologists, who have served on the Japanese Board of Urology, diagnosed the degree of the BPO (0 approximately VI) by watching the video recordings. The degree of obstruction revealed by cystourethroscopy was dependent upon the subjective impression of each urologist who wrote their diagnoses on questionnaires. RESULTS: A positive correlation was found between the results of the PFS and the subjective evaluations based on the cystourethroscopy video (p < 0.001), and the trained urologists arrived at a similar obstruction grade in most cases. However, relatively large gaps between linear PURR and cystoscopic finding were found in some cases. We suggest that these gaps could be caused by dynamic obstructions which cannot be detected by cystourethroscopy. CONCLUSIONS: Even though it is difficult to establish an objective measurement of the degree of a BPO using cystourethroscopy, our results show that it is a simple and reliable tool for the assessment of BPO in most cases.

Aged↗
PubMed2000

Bladder dysfunction due to Behçet's disease.

Behçet's disease is a multiple disorder in which urogenital involvement mainly consists of genital aphthous ulcers, epididymitis, urethritis and recurrent cystitis. We report 2 cases of neurogenic bladder due to Behçet's disease. Both cases showed detrusor hyperreflexia and detrusor-sphincter dyssynergia. One case has been managed by twice-daily intravesical oxybutynin treatment (5 mg/10 ml) and clean intermittent catheterization (CIC) 7 times/day, and the other case has been managed by CIC 6 times/day.

Behcet Syndrome↗
PubMed2000

[Management of unilateral renal cystine calculi via percutaneous nephrolithotripsy in a child with a contralateral non-functional kidney--a case report].

A 2-year old boy visited our clinic with a chief complaint of high fever. A past history of acute renal failure due to cystine stones and cystinuria was expressed. Abdominal rentogenograms and CT demonstrated a right ureteral stone and a left renal stone. Furthermore renogram evaluation indicated non-function of the right kidney and dysfunction in the left kidney. Since right ureteral stone moved into bladder seven days post-admission, right ureteroscopy, left PNL, and cystolithotripsy were performed. Considering that right ureteral stenosis was determined by ureteroscopy, balloon dilation against the stenotic ureteral wall was performed. Left PNL and cystolithotripsy were successfully performed. No intraoperative complications occurred and no symptoms of signs of recurrence of the underlying metabolic disease were evident four months postoperatively.

Child, Preschool↗
PubMed2000

[Extragonadal germ cell tumor coexisted with renal cell carcinoma--a case report].

A patient was 31-year-old man with the chief complaint of 38 degrees C fever. He was pointed out left renal tumor by abdominal ultrasonography and computerized tomography (CT). CT revealed left infraclavicular, mediastinal and retroperitoneal lymph nodes swelling and left renal tumor. Serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (HCG-beta) level were elevated. The diagnosis of extragonadal germ cell tumor and left renal cell carcinoma was confirmed pathologically by infraclavicular lymph node and renal biopsy. He was treated with 4 courses of BEP regimen and interferon-alpha, cimetidine therapy for 2 weeks preoperatively. After serum tumor markers were normal level, he underwent left radical nephrectomy and left infraclavicular, mediastinal and retroperitoneal lymph node dissection. The histology of all lymph nodes was necrotic tissue, but operation was incomplete. Therefore VIP therapy was performed postoperatively. This is the first case of extragonadal germ cell tumor coexisted with renal cell carcinoma in the world.

Adult↗
PubMed2000

A simple technique to change an obstructed ureteral stent in patients with an ileal conduit.

PURPOSE: We describe a simple technique to replace an obstructed ureteral stent in patients with an ileal conduit and ureteral stenosis. MATERIALS AND METHODS: Our study included 4 patients with an ileal conduit and ureteral stenosis. A total of 10 obstructed ureteral stents were replaced with a new stent using this simple technique under radiographic guidance. RESULTS: All obstructed ureteral stents were successfully replaced with a new stent without endoscopy, percutaneous nephrostomy or any special devices. CONCLUSIONS: Our technique is simple, easy and highly successful for changing an obstructed ureteral stent.

Device Removal↗
PubMed1999

Characteristics of detrusor contractility during micturition in diabetics.

Pressure-flow studies were performed in 26 diabetics without bladder-outlet obstruction to objectively quantify detrusor activity and its variance during micturition by using the watts factor (WF) and to clarify the factors inducing a post-void residual volume (PVR). The WFmax values obtained from the pressure-flow studies were low in the majority of diabetics. There was a significant negative correlation between WFmax and PVR. A fading contraction strength during voiding was also observed that gave rise to an increased volume of residual urine, indicating that detrusor activity could not be maintained until the bladder was completely emptied in the diabetics. A positive correlation between bladder capacity and PVR was also observed. Our results indicate that residual urine in diabetics is related to a decrease in the maximum detrusor contraction strength, the fading of detrusor contractility during voiding, and an increase in the size of the bladder.

Adult↗
PubMed1999

Postmeiotic modifications of spermatogenic cells are accompanied by inhibition of telomerase activity.

We investigated whether testicular telomerase activity is due to telomerase expression in all cells or expression in a limited number of cells. Telomerase activity was assayed in highly purified fractions of spermatogonia cells plus primary spermatocytes, secondary spermatocytes plus round spermatids, secondary spermatocytes plus spermatids plus spermatozoa, round spermatids, or spermatozoa prepared from healthy or cryptorchid animals. Telomerase activity was additionally assayed in testicular tissue of prepubertal animals and animals with Sertoli cell only pathophysiology. Telomerase activity was detected in fractions containing primary spermatocytes and/or secondary spermatocytes and/or spermatids. Fractions enriched in round spermatids were positive for telomerase activity. In contrast, spermatozoa or Sertoli cell fractions were negative for telomerase activity. Using the relative telomerase activity assay and the sensitive quantitative telomerase assay to quantify telomerase activity, we showed that induction of cryptorchidism does not result in quantitative alterations in testicular tissue telomerase activity. In addition, elimination of round spermatids does not lead to significant alterations in testicular tissue telomerase activity. The present results suggest that the male gamete telomerase activity is inhibited during spermiogenesis. Furthermore, it appears that spermatogonia/primary spermatocytes are the main sources of telomerase activity in the testis.

Animals↗
PubMed1999

Highly sensitive quantitative telomerase assay of diagnostic testicular biopsy material predicts the presence of haploid spermatogenic cells in therapeutic testicular biopsy in men with Sertoli cell-only syndrome.

The role of a telomerase assay in the recognition of Sertoli cell-only syndrome with testicular foci of haploid cells was evaluated. Men with Sertoli cell-only syndrome (n = 23) were given a new diagnostic testicular biopsy. Part of the biopsy was stained and the remainder was processed for the quantitative telomerase assay. After 3-13 months, a therapeutic testicular biopsy was performed. This material was minced and then examined using confocal laser scanning microscopy and fluorescent in-situ hybridization. Histology of diagnostic testicular biopsy material confirmed the diagnosis of Sertoli cell-only syndrome in all the participants. All seven men with a telomerase assay value in their diagnostic testicular biopsy of >42 total product generated (TPG) U/microg protein had haploid cells (i.e. spermatozoa and/or spermatids) in their therapeutic testicular biopsy. Among participants with telomerase assay values <42 TPG U/microg protein, only one man had haploid cells in his therapeutic testicular biopsy. Thus, telomerase assay values >42 TPG U/microg protein in the diagnostic biopsy identified 87.5% of the Sertoli cell-only syndrome men with haploid cells in their therapeutic testicular biopsy. Significantly higher values of the telomerase assay were found in men with testicular foci of haploid cells than in men without these foci. The use of a quantitative telomerase assay biopsy appears to be important for identifying those men with Sertoli cell-only syndrome who have foci of haploid cells and can be candidates for assisted reproduction techniques.

Adult↗
PubMed1999

Ooplasmic injections of rabbit round spermatid nuclei or intact round spermatids from fresh, cryopreserved and cryostored samples.

We compared the outcome of ooplasmic round spermatid nuclear injections (ROSNI) versus intact round spermatid injections (ROSI). Rabbit round spermatid nuclei and intact round spermatids were recovered and injected into rabbit oocytes (groups A and B, respectively). Fertilization, cleavage and embryonic development rates were compared. In additional studies, five protocols for cryopreservation of round spermatids and two protocols for cryostorage of round spermatids were applied. The outcome of ROSNI techniques using frozen-thawed or cryostored-warmed round spermatids was evaluated. The cleavage rate and the overall morula plus blastocyst development rate were significantly larger in group A than group B. ROSNI procedures are superior to ROSI techniques in the rabbit. The largest fertilization, cleavage and embryonic development rates after ROSNI techniques using cryopreserved or cryostored round spermatids were demonstrated in groups of round spermatids in which a mixture of seminal plasma plus test yolk buffer was employed as an extender, and dimethyl sulphoxide plus a high concentration of glycerol served as cryoprotectants. It appears that the seminal plasma contains factors protecting round spermatids during cryopreservation or cryostorage, and/or the employment of two cryoprotectants has a beneficial role in the maintenance of round spermatid reproductive capacity.

Animals↗
PubMed1999

Effects of hypercholesterolaemia on Leydig and Sertoli cell secretory function and the overall sperm fertilizing capacity in the rabbit.

The effects of hypercholesterolaemia on testicular endocrine and exocrine function were evaluated. The influence of hypercholesterolaemia on sperm quality, quantity, and fertilizing potential was also determined. Ten mature rabbits (group A) were fed chow containing 3% cholesterol for 12 weeks. Ten control rabbits (group B) were fed normal chow for the same period. At the end of the experimental period testosterone profiles and sperm parameters were evaluated and the sperm reproductive potential was assessed by in vitro fertilization (IVF) techniques. Peripheral serum testosterone responses to testicular stimulation with human chorionic gonadotrophin, androgen-binding protein activity in testicular cytosols, sperm concentration, sperm motility, length of sperm midpiece, and IVF outcome were all significantly lower in group A than in group B. In contrast, serum cholesterol concentrations were significantly higher in group A. There were no significant differences in either testicular versus intra-abdominal temperature differences or cholesterol concentrations in seminal plasma or testicular tissue between groups A and B. The results suggest that hypercholesterolaemia has a detrimental effect on Leydig and Sertoli cell secretory function, spermatogenesis, epididymal sperm maturation process, and the overall sperm fertilizing capacity.

Animals↗