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Biomedical subjects

Yoshiyuki Kojima

Publications and source records attributed to Yoshiyuki Kojima.

At least 19 recordsLinked to original sources
PubMed2007

Laparoscopic management for urachal cyst in a 9-year-old boy.

We report a boy with urachal cyst managed laparoscopically. A 9-year-old boy was referred from another hospital with a history of low abdominal pain. We laparoscopically excised the urachal cyst, removing all structures within the umbilicovesical fascia, including the urachus and each medial umbilical ligament, as well as the associated peritoneum from the umbilicus to the bladder dome. Laparoscopic management of urachal disease can be performed safely, with minimal postoperative pain, excellent cosmetic results and early ambulation. We advocate the use of laparoscopic treatment of urachal anomalies in children.

Child↗
PubMed2007

Influence for testicular development and histological peculiarity in the testes of flutamide-induced cryptorchid rat model.

OBJECTIVES: To investigate influence for the testicular development and to assess the usefulness as an animal model, cryptorchid rats were induced by exposure to flutamide during the fetal period and their testes examined histologically. METHODS: Flutamide was injected into the abdomen of pregnant rats for 7 days from the 14th to 20th day of gestation. The male offspring in which cryptorchidism was observed at 28 days after birth were defined as the model rats. They were divided into four groups by dosage of flutamide (2.5 mg, 5 mg, 7.5 mg, 15 mg per day), and their testicular weight, spermatogenesis (modified Johnsen score), and germ cell apoptosis were examined histochemically at 10 weeks after birth. RESULTS: The incidence of cryptorchidism including both unilateral and bilateral in the 2.5, 5, 7.5 and 15-mg flutamide groups was 58.3%, 81.9%, 93.6% and 91.0%, respectively. In the model rats, the undescended testes were located at the caudal end of the abdominal cavity, and these testes weighed less than the contra-descended testes in each group. Histologically, apoptotic cells were markedly increased, the seminiferous tubules were degenerated and disturbance of spermatid differentiation was observed in the undescended testes compared with the normal or contra-lateral descended testes. CONCLUSIONS: We found out that the incidence of undescended testes increased in a flutamide dose-dependent manner. The findings of histological examination were independent of the administrated dose of flutamide and it is suggested that exposure of the testes to abdominal temperature causes spermatogenic arrest with germ cell apoptosis. The present animal model indicates high incidence of above 90%, has no surgical stress and dose not require special techniques. We believe that the present model is a useful tool for the understanding of pathogenesis and treatment of cryptorchidism and further biological research into spermatogenesis.

Animals↗
PubMed2006

Quantification of alpha1-adrenoceptor subtypes by real-time RT-PCR and correlation with age and prostate volume in benign prostatic hyperplasia patients.

BACKGROUND: We used a real-time reverse transcriptase polymerase chain reaction (RT-PCR) method for quantification of each alpha(1)-adrenoceptor (alpha(1)-AR) subtype expression level, and examined whether age and prostate volume influence human prostate alpha(1)-AR subtype expression. METHODS: Enrolled in our study were 75 men with lower urinary tract symptoms (LUTS) secondary to untreated benign prostatic hyperplasia (BPH). Real-time RT-PCR was performed using prostate biopsy specimens to quantify the expression level of each alpha(1)-AR subtype. RESULTS: The median expression level (interquartile range) was 1.24 (0.66-2.32), 0.16 (0.10-0.33), and 1.11 (0.75-2.27) x 1,000 copies/beta-actin for alpha(1a)-, alpha(1b)-, and alpha(1d)-AR mRNA, respectively. The expression levels differed with the individual. The expression levels of alpha(1a)-AR, alpha(1d)-AR, and total alpha(1)-AR mRNA showed a significant positive correlation with patient age, but did not correlate with prostate volume. CONCLUSION: The difference in the expression of the alpha(1)-AR subtype with the patient may be the cause of the difference in the effectiveness of several subtype-selective alpha(1)-AR antagonists from patient to patient. The increase of alpha(1)-AR mRNA expression level with age could be an important factor in the pathogenesis of clinically significant BPH.

Adrenergic alpha-Antagonists↗
PubMed2006

Genes associated with the formation of germ cells from embryonic stem cells in cultures containing different glucose concentrations.

In a previous study, we established a system for visualizing the development of germ cells from mouse embryonic stem (ES) cells in culture using knock-in ES clones in which visual reporter genes were expressed from the mouse vasa homolog, Mvh. While assessing various culture conditions, we found that germ-cell formation was markedly depressed in low glucose medium. Using a repeated polymerase chain reaction (PCR) subtraction method, we identified genes that were differentially expressed in low versus high glucose media. Three genes that were predominantly expressed in high glucose medium, thioredoxin-interacting protein (Txnip), pituitary tumor-transforming gene 1 (Pttg), and RuvB-like protein 2 (RuvBl2), were further investigated. These genes were also found to be highly expressed in adult and embryonic gonads, and RuvBl2 in particular, which encodes an ATP-dependent DNA helicase, was specifically detected in the spermatocytes and spermatids of the adult testis as well as in primordial germ cells. Furthermore, using a green fluorescent protein (GFP) fusion construct, we found that RuvBl2 was expressed in both the nucleus and cytoplasm of testicular germ cells. These findings suggest a possible relationship between glucose metabolism and germ-cell development.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2006

Assessment of serum follicle-stimulating hormone level and testicular volume for prediction of paternity potential in pubertal boys who underwent bilateral orchiopexy in childhood.

PURPOSE: We examined infertile adults for the presence of spermatozoa in the testes, serum FSH level and testicular volume to predict paternity potential in pubertal boys who had undergone bilateral orchiopexy in childhood. MATERIALS AND METHODS: The study included 58 idiopathic infertile men (group 1), 14 infertile men who had undergone bilateral orchiopexy in childhood (group 2) and 21 pubertal boys who had undergone bilateral orchiopexy in childhood (group 3). We evaluated the correlation between FSH level and testicular volume in all groups. In groups 1 and 2 the testes were examined for the presence of spermatozoa using bilateral testicular biopsy samples. RESULTS: Judging from the presence of spermatozoa in the testes and correlation between FSH level and testicular volume, 14 patients in group 1 (24%) were categorized as being at high risk, 32 (55%) at intermediate risk and 12 (21%) at low risk for loss of paternity potential, with spermatozoa positive rates of 0%, 49% and 100%, respectively. In comparison, 4 patients in group 2 (29%) were categorized as being at high risk, 7 (50%) at intermediate risk and 3 (21%) at low risk, with spermatozoa positive rates of 0%, 43% and 100%, respectively. According to this categorization, 19% of pubertal boys in group 3 were at high risk and may already have lost their paternity potential. CONCLUSIONS: Despite bilateral orchiopexy in childhood, some male adolescents may not have the potential for paternity.

Adolescent↗
PubMed2006

Long-term outcome of upper urinary tract carcinoma in situ: effectiveness of nephroureterectomy versus bacillus Calmette-Guérin therapy.

BACKGROUND: We examined the long-term outcome and compared the usefulness of nephroureterectomy with that of bacillus Calmette-Guérin (BCG) therapy for the management of upper urinary tract carcinoma in situ (CIS). METHODS: We retrospectively reviewed the post-treatment course of 17 patients with CIS of the upper urinary tract who had undergone either a nephroureterectomy (group A, n = 6) or BCG therapy (group B, n = 11) at our institute. RESULTS: Median follow up was 58.3 months (range 1-120 months). Four of the six patients in group A (67%) had no recurrence and remained cystoscopically, cytologically and radiographically free of disease. The cytology became negative after an 8-week course in nine of the eleven patients in group B (82%; eight of ten units, 77%). Two of the nine patients showed recurrence after BCG therapy. One patient died of respiratory failure caused by a side-effect of BCG, which was interstitial pneumonia. There was no significant difference in either the 5-year recurrence-free survival or the 5-year cancer-specific survival between groups A and B. CONCLUSIONS: BCG therapy for CIS of the upper urinary tract is as effective as nephroureterectomy in long-term outcome, although it has some dangerous aspects. Further experience with treatment of CIS of the upper urinary tract is required.

Adjuvants, Immunologic↗
PubMed2006

Mathieu and Barcat repair with a V incision sutured meatoplasty for secondary hypospadias surgery.

AIM: Today single-stage methods are more frequently selected for hypospadias repair than multistaged methods, but complications cannot always be avoided. We employed two kinds of meatal based flip-flap urethroplasty procedures for those with an unsuccessful primary hypospadias repair. PATIENTS AND METHODS: From 1997 to 2005, a meatal based flip-flap urethroplasty was performed as a secondary hypospadias surgery on 17 patients. Basically we attempted the Mathieu repair, but when the wings of the glans were not generously widened and the urethral groove was not sufficiently deep we applied the Barcat procedure. While 11 patients were repaired with the Mathieu technique, six patients underwent the Barcat repair. The V incision sutured meatoplasty was added to obtain a natural ventral slit-like meatus. RESULTS: Ten of the 11 patients who underwent the Mathieu repair had a good outcome, but one patient developed a urethrocutaneous fistula. None of the six patients repaired with the Barcat procedure encountered postoperative complications. Cosmetically, a vertical slit was constructed near the normal neomeatus with the Mathieu and V incision sutured (MAVIS) meatoplasty and the Barcat and V incision sutured (BAVIS) meatoplasty. CONCLUSIONS: The Mathieu or the Barcat meatal based flip-flap urethroplasty procedure is feasible as a salvage surgery for those with relatively short urethral defects and adequate mobile ventral skin if an exact procedure is selected. Excellent cosmetic results could be obtained by adding the technique of V incision sutured meatoplasty.

Humans↗
PubMed2006

Role of transcription factors Ad4bp/SF-1 and DAX-1 in steroidogenesis and spermatogenesis in human testicular development and idiopathic azoospermia.

BACKGROUND: Ad4bp/SF-1 and DAX-1 are orphan members of the nuclear hormone receptor superfamily of transcription factors. In order to obtain better understandings of human testicular steroidogenesis and spermatogenesis, we examined the expression levels of both factors in human normal and idiopathic azoospermic testes and investigated their physical meaning. METHODS: First, we examined the expression level of Ad4bp/SF-1 and DAX-1 by quantitative reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry and western blotting analysis using eight normal human testicular tissues from infants to adults. Second, we performed quantitative RT-PCR using testicular biopsy samples obtained from 22 idiopathic azoospermic patients to examine the expression of Ad4bp/SF-1 and DAX-1, and analysed the correlation between the expression levels of both factors and the serum hormone levels or histological evaluation to study their potential correlation with steroidogenesis and spermatogenesis on idiopathic azoospermia. RESULTS: The expression levels of both factors in the normal testes increased with testicular development. Ad4bp/SF-1 was abundantly expressed in Leydig cell, whereas DAX-1 was expressed in Sertoli cells. The expression level of Ad4bp/SF-1 in idiopathic azoospermic patients testes positively correlated with serum testosterone (P < 0.05). The average expression levels of DAX-1 mRNA for patients with maturation arrest (0.39 +/- 0.19) and Sertoli cell-only syndrome (0.13 +/- 0.08) were lower than that with hypospermatogenesis (1.60 +/- 1.32) and normal spermatogenesis (1.30 +/- 1.41). CONCLUSION: Ad4bp/SF-1 is important for the maintenance of steroidogenesis in the human testis. DAX-1 plays a critical role in spermatogenesis in the human testis, and Sertoli cell-only syndrome and maturation arrest may result from abnormal Sertoli cell function that disrupts the normal progression of spermatogenesis.

Adolescent↗
PubMed2006

Pseudo-clitoromegaly associated with congenital prepubic sinus.

We operated on a 12-year-old girl who had clitoromegaly and a sinus on the midline prepubic area congenitally. The prepubic sinus appeared to point to the clitoris on the preoperative magnetic resonance image, but the relation between the sinus and clitoromegaly was unclear. Gray-brown discharge was emitted at the site of dissection between the prepuce and clitoris and the size of the clitoris became normal. The sinus was excised, revealing a tract 1.5 cm long that extended to the retropubic sinus, and ended in a fibrous tract that was linked to the clitoris. This suggested pseudo-hypertrophy because of the discharge collected in the end of the prepubic sinus.

Adrenal Hyperplasia, Congenital↗
PubMed2006

Complete response of a recurrent advanced urachal carcinoma treated by S-1/cisplatin combination chemotherapy.

We report a case of recurrent advanced urachal carcinoma with right internal iliac node and left lung metastases in a 34-year-old man. After receiving partial cystectomy including en bloc resection of the urachus and with bilateral pelvic lymph node dissection, he was treated with five courses of S-1 and cisplatin combination chemotherapy. He remains free from the disease after a 30-month follow-up period. S-1/cisplatin combination chemotherapy is suggested to be a potent tool for controlling advanced urachal carcinoma.

Adenocarcinoma↗
PubMed2006

Development of multiple calculi in the duplex system ureterocele.

A 61-year-old man presented complaining of pollakisuria and nocturia. A plain radiograph of his kidney, ureter and bladder and intravenous urography revealed numerous calculi in the upper kidney of his left renal pelvis and ureterocele. A transurethral incision of ureterocele (TUI-ureterocele) and extracorporeal shock wave lithotripsy were performed. On TUI-ureterocele, the many calculi were found to be almost the same size and spherical in form. The postoperative clinical course was uneventful.

Humans↗
PubMed2005

Effect of testicular biopsy in childhood on spermatogenesis, fertility, and paternity in adulthood--a mouse model study.

OBJECTIVES: To study the effect of testicular biopsy in childhood on spermatogenesis, fertility, and paternity in subsequent adulthood using an animal model. Considerable controversy exists as to whether testicular biopsy should be performed in children. METHODS: Four-week-old male ICR mice were subjected to unilateral testicular biopsy (group 1), bilateral biopsy (group 2), or a sham operation (group 3). At 8 weeks of age, the testicular weight, seminiferous tubular diameter, and manifestation of apoptosis were examined. The motility of sperm obtained from the epididymides of the same testes was also examined. Fertility and paternity was assessed in each mouse by housing it with 2 age-matched females for 2 weeks. RESULTS: No significant differences were found in the testicular weight, mean seminiferous tubular diameter, or number of apoptotic germ cells between the biopsied and unbiopsied side in group 1 or between groups 2 and 3. No significant differences were noted in the average sperm motility rate between the biopsied (30.5% +/- 14.5%) and unbiopsied side (35.8% +/- 19.2%) in group 1, or between groups 2 (37.6% +/- 18.0%) and 3 (39.3% +/- 10.0%). All females who coupled with the male mice in all groups became pregnant. The average number of offspring from the 2 female mice was not significantly different among the three groups (group 1, 13.1 +/- 2.3; group 2, 12.3 +/- 2.0; and group 3, 11.3 +/- 3.0). CONCLUSIONS: The spermatogenesis, fertility, and paternity of mature mice were unaffected by testicular biopsy in childhood.

Age Factors↗
PubMed2005

Effect of epidermal growth factor on spermatogenesis in the cryptorchid rat.

PURPOSE: Epidermal growth factor (EGF) is secreted mainly from the submandibular glands. Submandibular gland ablation causes a marked decrease in male fertility, which suggests that EGF influences spermatogenesis. We investigated the effect of EGF in combination with orchiopexy on cryptorchid rat testes in which tubular deterioration had become partially irreversible. MATERIALS AND METHODS: Unilaterally cryptorchid rats were obtained by daily administration of 7.5 mg flutamide (Nihonkayaku, Tokyo, Japan), an androgen receptor antagonist, to pregnant rats. At age 10 weeks the unilaterally cryptorchid rats underwent orchiopexy with or without EGF administered into the cryptorchid testis. EGF solution (10 microg/ml) was delivered into the seminiferous tubules by retrograde perfusion through the rete testis. At 14 days testicular recovery was assessed based on the maturity of spermatogenesis using a modified Johnsen score and from the number of apoptotic germ cells per seminiferous tubule. RESULTS: Mean Johnsen score +/- SEM was significantly higher in the orchiopexy with EGF than in the orchiopexy without EGF group (7.85 +/- 0.12 vs 7.12 +/- 0.13, p <0.001). The number of apoptotic germ cells tended to be smaller in the orchiopexy with EGF group than in the orchiopexy without EGF group (0.16 +/- 0.05 vs 0.28 +/- 0.08). CONCLUSIONS: Although orchiopexy for cryptorchidism partly improved spermatogenesis, recovery was limited. EGF administered in combination with orchiopexy was more effective for spermatogenesis than orchiopexy alone. This may be applicable in patients with cryptorchidism.

Analysis of Variance↗
PubMed2005

Novel technique for correcting penile curvature with severe hypospadias; ventral lengthening with tunica vaginalis flap patching.

The adequate correction of penile curvature is essential for successful hypospadias surgery. We describe a novel technique to correct severe penile curvature with a tunica vaginalis flap on the penile ventrum. We applied a tunica vaginalis flap to lengthen the ventral aspect of the tunica albuginea in two boys with significant curvature and proximal hypospadias. Tunica vaginalis flap patching to the ventral aspect of the penis is safe and technically feasible. If penile curvature is severe or the penis is small in hypospadiac patients, lengthening the ventral aspect using a tunica vaginalis flap is likely to expand instead of dorsal plication or ventral graft.

Child, Preschool↗
PubMed2005

Congenital prepubic sinus: a variant of dorsal urethral duplication (Stephens type 3).

Abstract A 3-year-old boy was admitted for yellowish discharge from a tiny opening in the midline prepubic area on the dorsal base of the penis. No other symptom related to the genitourinary tract was noted. Sinuousgraphy showed a non-communicating sinus tract with the urinary tract. At surgical exploration, through a diamond-shaped incision, a 4.5 cm-long sinus was found that ended blindly as a fibrous cord at the anterior surface of the pubic symphisis. Histologically, it was lined by stratified squamous epithelium and surrounded by bundles of smooth muscle and collagen. According to Stephens' classification, the sinus appears to be a variant of dorsal urethral duplication of Stephens type 3.

Child, Preschool↗
PubMed2005

Scrotal dartos flap for the prevention of the urethrocutaneous fistula on hypospadias urethroplasty.

BACKGROUND: Urethrocutaneous fistula is a common complication of urethroplasty for severe hypospadias, even when a microsurgical technique is applied. PATIENTS AND METHODS: From June 2001 to July 2003, we applied the scrotal dartos flap wrapping technique to prevent the occurrence of urethrocutaneous fistula in 14 patients with hypospadias. RESULTS: Hypospadias was repaired without fistula formation in all but one patient, who developed a tiny fistula which was later closed successfully by a simple procedure. CONCLUSIONS: We recommend the scrotal dartos wrapping technique for covering the neourethra with a well-vascularized flap because of fewer complications, although the procedure to obtain the vascularized flap may take longer.

Child, Preschool↗
PubMed2005

Accuracy of ultrasonography and magnetic resonance imaging in the diagnosis of non-palpable testis.

BACKGROUND: Studies were needed to evaluate the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) for diagnosing non-palpable testis, and to study the clinical usefulness of US and MRI before surgical exploration. METHODS: Fifty-six patients with non-palpable testis aged 1--12 years were examined between 1993 and 2002. Forty-six patients (55 non-palpable testes) underwent US. Forty patients (47 non-palpable testes) were examined using MRI. Both US and MRI were used in 29 patients (34 non-palpable testes). We used Fisher's exact probability test to compare the results of these graphic examinations with the surgical or laparoscopic findings for the non-palpable testis. RESULTS: Ultrasonography had a sensitivity of 76%, a specificity of 100%, and an accuracy of 84% in the diagnosis of non-palpable testis, whereas MRI had a sensitivity of 86%, a specificity of 79%, and an accuracy of 85%. CONCLUSIONS: There were no statistically significant differences in the accuracy rates of US and MRI for diagnosing non-palpable testis. Laparoscopy or inguinal exploration should be performed even if these graphic examinations demonstrate the absence of a testis, because some patients with a non-palpable testis were found to be false negatives. We recommend US as the first step after clinical examination, and MRI could be performed when the US findings are negative preoperatively for a non-palpable testis.

Child↗