Fine structural and immunohistochemical detection of collar enamel in the teeth of Polypterus senegalus, an actinopterygian fish.

This is the first detailed report about the collar enamel of the teeth of Polypterus senegalus. We have examined the fine structure of the collar enamel and enamel organ of Polypterus during amelogenesis by light and transmission electron microscopy. An immunohistochemical analysis with an antibody against bovine amelogenin, an antiserum against porcine amelogenin and region-specific antibodies or antiserum against the C-terminus, middle region and N-terminus of porcine amelogenin has also been performed to examine the collar enamel matrix present in these teeth. Their ameloblasts contain fully developed Golgi apparatus, rough endoplasmic reticulum and secretory granules. During collar enamel formation, an amorphous fine enamel matrix containing no collagen fibrils is found between the dentin and ameloblast layers. In non-demineralized sections, the collar enamel (500 nm to 1 µm thick) is distinguishable from dentin, because of its higher density and differences in the arrangement of its crystals. The fine structural features of collar enamel in Polypterus are similar to those of tooth enamel in Lepisosteus (gars), coelacanths, lungfish and amphibians. The enamel matrix shows intense immunoreactivity to the antibody and antiserum against mammalian amelogenins and to the middleregion- and C-terminal-specific anti-amelogenin antibodies. These findings suggest that the proteins in the enamel of Polypterus contain domains that closely resemble those of bovine and porcine amelogenins. The enamel matrix, which exhibits positive immunoreactivity to mammalian amelogenins, extends to the cap enameloid surface, implying that amelogenin-like proteins are secreted by ameloblasts as a thin matrix layer that covers the cap enameloid after enameloid maturation.

Successful treatment of retrograde ejaculation with amezinium.

The effect of amezinium, a new type of antihypotensive agent, on retrograde ejaculation was evaluated in 3 patients with retrograde ejaculation. The patients received 10 mg amezinium orally once a day. All patients achieved antegrade ejaculation. Semen analyses revealed 6-50 x 10(6)/mL (mean 28.7 x 10(6)/mL) sperm with a motility of 20-50% (mean 36.7%). The wives of 2 patients became pregnant within 6 months of the initial treatment. None of the patients had any side effects. It would appear that amezinium is a useful treatment for retrograde ejaculation.

Results and complications of laparoscopic Palomo varicocelecctomy.

The laparoscopic Palomo varicocelectomy were performed in 38 males with left-sided varicocele. The mean operation time was 37 (25-56) min. There were no intra-abdominal visceral or vascular complications during operation. Neither testicular atrophy nor recurrence was observed postoperatively. However, hydrocele formation was found in two (5.3%) patients. These findings suggest that laparoscopic Palomo varicocelectony is a safe and effective procedure for patients with varicocele.

Androgen receptor gene and male genital anomaly.

Male sexual differentiation, testicular descent, and spermatogenesis require androgens. Their action is mediated through the androgen receptor (AR), which binds to the androgen responsive element on DNA and regulates gene transcription. No mutations in any of the AR gene exons 1-8 are detected in males with isolated cryptorchidism, hypospadias, micropenis, or idiopathic male infertility. In addition, the CAG repeat length in exon 1 of the AR gene does not expand in males with isolated cryptorchidism, hypospadias, micropenis, or idiopathic male infertility. These facts indicate that an alteration of the AR gene is rare in these males. However, further studies will permit a better clarification on the relevance of the AR gene abnormalities to the development of isolated cryptorchidism, hypospadias, micropenis, or impaired spermatogenesis.

Absence of microdeletions in the Y chromosome in patients with Prader-Willi syndrome with cryptorchidism.

Unilateral or bilateral cryptorchidism is found in 80-100% of male patients with Prader-Willi syndrome (PWS). Recently, the relationship between Yq deletions and cryptorchidism has been assessed. However, the relationship between Yq deletions and PWS patients with cryptorchidism remains unclear. Polymerase chain reaction (PCR) amplification of 51 DNA loci encompassing all of the regions for azoospermia factor (AZF) of the Y chromosome, including the deleted in azoospermia (DAZ) and ribonucleic acid-binding motif (RBM) genes, were examined for microdeletions in 10 PWS males with cryptorchidism and 20 healthy control male subjects. No microdeletions of 51 loci were found in any of the PWS males. The present study therefore suggests that microdeletions in the AZF regions of the Y chromosome do not relate to the occurrence of cryptorchidism in PWS patients.

Effect of testosterone replacement therapy on serum PSA in patients with Klinefelter syndrome.

The effect of testosterone replacement therapy on serum prostate-specific antigen (PSA) was investigated in 11 patients with Klinefelter syndrome. Significant increases in serum testosterone level and prostate volume were observed after testosterone replacement therapy. However, serum PSA level did not change after testosterone replacement therapy. It would appear that serum PSA is not influenced by exogenous testosterone in patients with Klinefelter syndrome.

Stress and testicular germ cell apoptosis.

Chronic immobilization stress provokes an increase in serum corticosterone, which causes the decline in testosterone concentration. The stress and glucocorticoid administration induce germ cell apoptosis in rat testes. The cell type that has been shown to undergo apoptosis is spermatogonia. Since a potent glucocorticoid receptor agonist completely suppressed glucocorticoid induced germ cell apoptosis, the regulation of transcription of gene mediated by the glucocorticoid receptor may enhance apoptosis of testicular germ cells. The apoptosis of testicular germ cells would involve certain specific gene activities and proteins, including Bcl-2 family, p53, and Fas. Molecular investigations may help to determine whether the different pathways possess mechanisms of germ cell apoptosis induced by somatic stress and glucocorticoids.

Epidemiology of prostatic cancer in East Asia.

Prostate cancer has become one of the most common malignancies in the world. The incidence of prostate cancer has rapidly increasing over the last decade in East Asia. In Japan, age-adjusted death rates due to prostate cancer rose from 4.4 to 8.6 per 100,000 between 1980 and 1998. Recent research has focused on age, race-related differences, patterns of familial aggregation, genetic factors, hormones, and diet. Epidemiological approach has identified several possible risk factors that may be useful for the prevention of prostate cancer and targeting high-risk individuals for early detection.

Screening for mutations of the androgen receptor gene in patients with isolated cryptorchidism.

OBJECTIVE: To evaluate the occurrence of mutations of androgen receptor (AR) gene in patients with isolated cryptorchidism. DESIGN: Controlled clinical study. SETTING: Yamagata University Hospital, Yamagata and Tokyo Electric Power Company Hospital, Tokyo, Japan. PATIENT(S): Patients with isolated cryptorchidism (n = 48) and a control group of men with normal phenotype (n = 20). INTERVENTION(S): Blood (lymphocyte DNA). MAIN OUTCOME MEASURE(S): Screening of the AR gene in exons 1-8 using single-strand conformational polymorphism analysis. RESULT(S): No abnormal band patterns were detected in patients with cryptorchidism or in control subjects within the eight exons of the AR gene. CONCLUSION(S): AR gene alterations appear to be an unlikely cause of isolated cryptorchidism.

CAG repeat length analysis and mutation screening of the androgen receptor gene in Japanese men with idiopathic azoospermia.

Because androgens are required for normal spermatogenesis, we are investigating abnormalities in the androgen receptor as a possible cause of impaired spermatogenesis in patients with idiopathic male infertility. The CAG repeat length in exon 1 and mutations of the androgen receptor gene were studied in 30 men with idiopathic azoospermia and in 51 fertile men. In men with azoospermia, plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were measured and testicular biopsies were performed. The CAG repeat length ranged from 19 to 30 (mean 23.4 +/- 2.9) and from 17 to 28 (mean 23.7 +/- 3.2) in men with azoospermia and in controls, respectively. There was no significant difference between the 2 groups. In men with azoospermia, the Johnsen testicular biopsy score negatively correlated with plasma FSH (P < .01). However, the Johnsen testicular biopsy score did not correlate with plasma LH and testosterone levels. The CAG repeat length did not correlate with the Johnsen testicular biopsy score, or with plasma concentrations of LH, FSH, and testosterone. No abnormalities in the androgen receptor gene were detected. These facts suggest that the CAG repeat length and alterations in the androgen receptor gene are not associated with the etiology of idiopathic azoospermia.

Mutation screening and CAG repeat length analysis of the androgen receptor gene in Klinefelter's syndrome patients with and without spermatogenesis.

BACKGROUND: Mutations of the androgen receptor (AR) gene give rise to a wide array of phenotypic abnormalities. A systematic analysis of the AR gene in patients with 47,XXY has not previously been performed. METHODS: Mutations of the AR gene and expansion of the CAG repeats in exon 1 of the AR gene were studied in 13 patients with Klinefelter's syndrome either with (n = 1) or without (n = 12) spermatogenesis. RESULTS: No abnormalities in the AR gene were detected by single strand conformational polymorphism analysis. The CAG lengths ranged from 17 to 27 (mean +/- SD 22.8 +/- 3.3, median 23) for Klinefelter patients or from 17 to 28 (mean +/- SD 23.2 +/- 2.6, median 23) for control subjects. X-inactivation analysis for the methylation status of the AR gene was performed in seven patients who were heterozygous for CAG repeats of different length, showing that the longer CAG repeat alleles underwent random but more frequent inactivation in five patients and skewed inactivation in two. CONCLUSIONS: An AR gene abnormality does not constitute an important factor for impaired spermatogenesis in patients with Klinefelter's syndrome.

Undermasculinized genitalia in a boy with an abnormally expanded CAG repeat length in the androgen receptor gene.

We report an 11-year-old boy with undermasculinized genitalia and an abnormally expanded CAG repeat length at exon 1 of the androgen receptor (AR) gene. He had microphallus and scrotal hypospadias with chordee, and underwent urethroplasty at 4 years of age. At 11 years of age, a gonadotropin releasing hormone (GnRH) test yielded a relatively high leutinizing hormone (LH) response (0.7-->20.4 IU/l) and a relatively low follicle-stimulating hormone (FSH) response (1.7-->4.8 IU/l), and an human chorionic gonadotropin (hCG) test showed sufficient responses of testosterone (0.7-->23.0 nmol/l) and dihydrotestosterone (0.38-->2.95 nmol/l). The CAG repeat length was 44 for the boy and ranged from 12 to 32 for 100 control males. The DNA sequences of the AR gene were normal for the exons 1-8 and for the splice donor, splice acceptor and branch sites. The markedly expanded CAG repeat length appears to be relevant to the undermasculinized genitalia of this boy, because such an expandsion, which has previously been reported only in spinal and bulbar muscular atrophy, is known to reduce AR function.

Possible involvement of the membrane-bound form of peroxiredoxin 4 in acrosome formation during spermiogenesis of rats.

Peroxiredoxins are novel peroxidases that exhibit divergent biological functions. The fourth member, Prx4, is synthesized with a signal sequence and, after processing, secreted as a 27-kDa form in most tissues. A 31-kDa Prx4 which corresponds to the unprocessed, membrane-bound form is found only in testis. This study was undertaken in order to investigate the role of the membrane-bound Prx4 during spermiogenesis in rats. The Prx4 transcript was observed in testes at 14 days of age, the age before puberty, and its level increased only slightly during aging. Only the secretable form of Prx4 was present before 30 days of age, but the membrane-bound Prx4 became detectable in adult testes, although sum of the two forms appeared to be the same after 21 days old. While weak immunoreactivity to the Prx4 antibody was detected in spermatogenic cells for all ages, a strong immunoreactivity was observed in the elongating spermatid and residual body of adult testis. Prx4 was present in the lumen of the endoplasmic reticulum, Golgi bodies, and the perinuclear space in young rat testes. However, the localization of Prx4 was restricted to membranes of the acrosomal vesicle of the elongated spermatid and was not detected in spermatozoon. Once spermiogenesis is accomplished, vesicles containing the membrane-bound Prx4 were released into the residual body, along with residual membranous components. Thus the conversion of the soluble form to the membrane-bound form may have a role in the acrosome formation during vesicular reorganization during spermiogenesis.

Hypospadias and the androgen receptor gene: mutation screening and CAG repeat length analysis.

We report on mutation screening and CAG repeat length analysis of the androgen receptor (AR) gene in 21 patients with hypospadias. The urethral meatus was located at the glandular region in six patients (glandular type), at the penile shaft in seven patients (penile type), and at the scrotal/perineal region in eight patients (scrotal/perineal type). Mutation screening was performed for exons 1-8 and their flanking introns (except for the CAG and GGC repeat regions at exon 1) by the heteroduplex detection method and showed no abnormal chromatograms. The CAG repeat length analysis was carried out using 50 normal boys and 50 fertile males as controls, and demonstrated no statistically significant difference in the median of CAG repeat lengths or in the frequency of long CAG repeats (> or = 26 or > or = 28) between the controls and the patients with the three different types of hypospadias. The results suggest that AR gene abnormalities do not constitute a major factor in the development of hypospadias.

Glucocorticoid hormone can suppress apoptosis of rat testicular germ cells induced by testicular ischemia.

OBJECTIVE: To evaluate the effect of dexamethasone, a potent synthetic glucocorticoid hormone, on apoptosis of testicular germ cells and vascular neutrophil adhesion after repair of testicular torsion in rats. DESIGN: Controlled laboratory study. SETTING: Department of Urology, Yamagata University School of Medicine, Yamagata, Japan. ANIMAL(S): Fifty-one male Sprague-Dawley rats. INTERVENTION(S): Dexamethasone, 10 mg/kg of body weight. MAIN OUTCOME MEASURE(S): Testicular germ-cell apoptosis (percentages of apoptotic tubules and apoptotic cells) and vascular neutrophil adhesion were assessed by using DNA nick-end labeling and the endothelial-neutrophil adhesion score, respectively. RESULT(S): Intravenous administration of dexamethasone at repair of 90-minute testicular torsion significantly inhibited testicular germ-cell apoptosis and vascular neutrophil adhesion. This inhibition was suppressed by intravenous injection of mifepristone, a glucocorticoid-receptor antagonist. CONCLUSION(S): Glucocorticoids can be administered for torsion in addition to conventional torsion repair.

Tumour angiogenesis and Ki-67 expression in phaeochromocytoma.

OBJECTIVE: To determine the expression of CD34 (to evaluate vascularity) and Ki-67 (as a proliferative index) in a variety of phaeochromocytomas and thus assess the utility of these markers as possible predictors of malignancy. PATIENTS AND METHODS: Deparaffinized tissue sections from 21 patients with benign and four with malignant phaeochromocytoma were assessed immunohistochemically to evaluate microvascular counts (using CD34 antigen) and the proliferative index (Ki-67 antigen, monoclonal antibody MIB-1). RESULTS: There was no statistical association between high microvascular counts and malignancy, but there was between the MIB-1 score and malignancy (P < 0.001). CONCLUSIONS: A high MIB-1 score in phaeochromocytoma suggests malignant behaviour in the component cells. The MIB-1 score may be a useful indicator for diagnosing malignant phaeochromocytoma.

Sutureless vasovasostomy using new vascular closure staples in rats.

To evaluate the efficacy of sutureless vasovasostomy using vascular closure staples, 20 male Sprague-Dawley rats were used for the study. In each rat, a sutureless vasovasostomy using vascular closure staples was performed on a randomly selected side, and a conventional end-to-end microsutured anastomosis was performed on the opposite side. Operation time was significantly shorter for sutureless vasovasostomy using vascular staples (p < .001). Four weeks after the surgery, however, patency rate and granuloma formation were not different for conventional end-to-end vasovasostomy vs. sutureless vasovasostomy. These findings suggest that sutureless vasovasostomy is simple to perform and requires fewer special technical skills. This procedure may provide an alternative to the conventional vasovasostomy.

Reevaluation of testicular biopsies of males with nonobstructive azoospermia in assisted reproductive technology.

Spermatogenesis was investigated in seminiferous tubules of 100 males with nonobstructive azoospermia. Forty-four (44%) cases had Sertoli-cell-only syndrome, 23 (23%) had spermatogonium in the tubules, 17 (17%) had primary spermatocyte in the tubules, and 16 (16%) had round or late spermatid in the tubules. No cases showed secondary spermatocyte present in the tubules. The mean serum follicle-stimulating hormone (FSH) in males with nonobstructive azoospermia was significantly higher than that in males with obstructive azoospermia (p < .001). The mean concentrations of serum FSH in cases with Sertoli-cell-only syndrome and spermatogonium in the tubules were significantly higher than those in cases with primary spermatocyte and spermatid in the tubules (p < .05-.001). The results indicate that the evaluation of testicular histology using the type of germ cells present in seminiferous tubules is available for assisted reproductive technology.