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Biomedical subjects

Yukio Osada

Publications and source records attributed to Yukio Osada.

14 recordsLinked to original sources
PubMed2006

Expression and distribution of OCTN2 in mouse epididymis and its association with obstructive azoospermia in juvenile visceral steatosis mice.

AIM: L-carnitine, an essential cofactor for mitochondrial, beta-oxidation of long-chain fatty acids, is known to play important roles in sperm maturation and metabolism when spermatozoa pass and acquire motility in the epididymis. We reported that obstructive azoospermia occurred in the epididymis in the juvenile visceral steatosis (JVS) mice, which are OCTN2 dysfunction mice caused by mutations in the gene encoding OCTN2, have been used for animal models of primary systemic carnitine deficiency. The aim of present study is to investigate the expression of OCTN2 protein in the mouse epididymis and its relation between the localization of OCTN2 and obstructive azoospermia in JVS mice as animal models for human male infertility. METHODS: Animals used in this study were wild-type (C57BL/6 J) mice (n = 4) and JVS mice (n = 4). We made a specific polyclonal antibody against OCTN2 and examined immunohistochemically the localization of OCTN2 in the mouse epididymis. RESULTS: OCTN2 was localized on the apical membrane of the principal cells of distal corpus and cauda epididymides. Immunocytochemistry demonstrated that OCTN2 was localized on the surface of microvillus upon the principal cells. In JVS mice, immunoreactivity started in a region immediately distal to where the sperm obstruction occurred. CONCLUSIONS: Our results suggest that OCTN2 functions as a carnitine transporter between the epithelium and the lumen in distal corpus and cauda epididymides and provides a clue as to why obstructive azoospermia is induced in distal parts of epididymis.

Animals↗
PubMed2006

[Yoke technique for severe proximal hypospadias].

UNLABELLED: PROPOSED: Various techniques have so far been reported for the repair of hypospadias, however, a one-stage procedure for the repair of severe proximal hypospadias still remains difficult to perform. We recently have begun to use the Yoke hypospadias repair technique for the treatment of severe proximal hypospadias. PATIENTS AND METHODS: As the chief surgeon, I performed a one-stage hypospadias repair on 40 proximal hypospadiac patients with severe fibrous chordee between July 1992 and December 2004. During the early period, eleven patients underwent urethroplasty by the Transverse Preputial Island Flap techinique (TPIF). Next, 10 patients underwent One-stage Urethroplasty with Parameatal Foreskin flap technique (OUPF IV). Finally, the most recent 19 had their hypospadias repaired by the Yoke technique. RESULTS: With the TPIF technique in the early periods, only 6 out of 11 patients underwent a successful repair (54.5%). With the OUPF IV technique, the success rate was only 60.0% (6 out of 10 cases). In contrast, 17 out of 19 cases treated by the Yoke technique in the most recent period had a successful repair, although proximal urethrocutaneous fistula and urethral stenosis occurred in one patient, respectively. A relatively high success rate was therefore obtained using the Yoke technique for the repair of severe proximal hypospadias. CONCLUSION: The Yoke techniques for the repair of hypospadias is therefore considered to be a safe and effective technique for the repair of proximal hypospadias because of the continuous skin flap of the ventral urethral plate and the prepuce with a blood supply from the circumferential vascular pedicle. We consider this technique to be very useful for the treatment of severe proximal hypospadias.

Adolescent↗
PubMed2005

Expression of novel organic cation/carnitine transporter (OCTN2) in the mouse pancreas.

Among the organic cation transporters, OCTN2 is identified as the most important carnitine transporter owing to the ability to transport carnitine. Although the OCTN2 is previously found in various tissues, there have been no reports showing the OCTN2 in the pancreas. In this study, we examined the expression and localization of OCTN2 in the mouse pancreas by the aid of an in situ hybridization technique and immunohistochemistry with anti-OCTN2 antibody. As a result, the OCTN2 expression was found in the A-cells for the first time. OCTN2 was not expressed in B-cells, notwithstanding that the metabolism of long-chain fatty acids, which are transported into the mitochondria with the help of carnitine, was expected for fatty acid-stimulated insulin secretion. Thus, this study suggests the possibility of carnitine uptake in the pancreatic A-cells through OCTN2 and implies the presence of carnitine transporter(s) other than OCTN2 in the B-cell.

Animals↗
PubMed2005

Antibiotic susceptibility testing of Mycoplasma genitalium by TaqMan 5' nuclease real-time PCR.

Mycoplasma genitalium is an important pathogen in male nongonococcal urethritis (NGU). Isolation of M. genitalium from clinical specimens by axenic culture is very difficult and time-consuming, and very few strains are available for antibiotic susceptibility testing. Primary isolation of M. genitalium by coculture with Vero cells improves the isolation rate significantly. However, some strains cannot be adapted to axenic culture. In this study, we determined the antibiotic susceptibility of M. genitalium strains grown in Vero cell culture with dilutions of antibiotics. Growth of M. genitalium was monitored by a quantitative PCR assay detecting a single-copy region of the mgpB adhesin gene. Growth inhibition in the presence of antibiotics was expressed as a percentage of the DNA load of controls grown in the absence of antibiotics. Eighteen strains were examined, including 6 new strains isolated from urethral swab specimens and 4 new strains isolated from urine specimens collected from Japanese men. Eight strains adapted to axenic culture were also tested by the conventional broth dilution method. The two methods had an acceptable correlation. Azithromycin was the most active drug against M. genitalium. Among the fluoroquinolones, moxifloxacin had the highest activity, with MICs ranging from 0.03 to 0.5 mg/liter, whereas ciprofloxacin and levofloxacin were considerably less active, with MICs ranging from 0.5 to 16 mg/liter and 0.25 to 4 mg/liter, respectively. MICs for tetracycline ranged from 0.125 to 4 mg/liter. This new method could increase the number of M. genitalium strains available for antibiotic susceptibility testing and significantly shorten the time from sampling to MIC results.

Animals↗
PubMed2005

Effects of different alpha-1 adrenoceptor blockers on proximal urethral function using in vivo isovolumetric pressure changes.

The effects of different alpha-1 adrenoceptor blockers on the urethra and the cardiovascular system were evaluated using an in vivo isovolumetric intra-urethral pressure model in New Zealand white rabbits. The urethra of anesthetized male rabbits was cannulated through the bladder and secured at the vesico-urethral junction. The distal side of urethra under the pubic bone was also closed to allow measurement of the intra-urethral pressure. Both the intra-urethral pressure and the femoral arterial pressure were monitored. The effects of five different alpha-1 adrenoceptor blockers on the increases in both the intra-urethral pressure and blood pressure induced by phenylephrine were then examined. The inhibition rate of the alpha-1 adrenoceptor blockers prazosin, bunazosin, terazosin, alfuzosin and tamsulosin on the increase in intra-urethral pressure caused as a result of contraction by phenylephrine was 87.5 +/- 4.5% (mean +/- S.E.), 88.0 +/- 7.2%, 86.2 +/- 6.2%, 81.4 +/- 4.8% and 92.5 +/- 5.0% respectively. The potency ranking of these alpha-1 adrenoceptor blockers was tamsulosin > bunazosin > prazosin > terazosin > alfuzosin. Their inhibition rate of the arterial pressure increase induced by phenylephrine was 81.9 +/- 5.0%, 86.2 +/- 5.9%, 76.0 +/- 6.0%, 63.6 +/- 5.7% and 58.0 +/- 5.2% respectively, with a potency ranking of bunazosin > prazosin > terazosin > alfuzosin > tamsulosin. We therefore conclude that the alpha-1 adrenoceptor blockers bunazosin and prazosin have a more potent action on both the urethra and the vascular system. However, tamsulosin and alfuzosin displayed a marked blockade of the increased urethral pressure induced by phenylephrine, with much less of a blockade of arterial pressure. In the present study, tamsulosin has been shown to be the most sensitive and powerful of the alpha-1 adrenoceptor blockers on urethral smooth muscle.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed2004

Hepatocyte growth factor activator inhibitor types 1 and 2 are expressed by tubular epithelium in kidney and down-regulated in renal cell carcinoma.

PURPOSE: Hepatocyte growth factor (HGF) and its receptor MET have been implicated in kidney development and renal cell carcinoma (RCC) progression. HGF is secreted as an inactive proform and it must be activated to initiate MET signaling. HGF activator (HGFA) activates pro-HGF in injured tissue. We evaluated the expression of HGFA and its endogenous inhibitors HAI-1 and HAI-2 in normal kidney and RCC. MATERIALS AND METHODS: We examined the gene expression of HGFA, HAI-1, HAI-2, HGF and MET in a normal kidney by laser captured microdissection, followed by reverse transcriptase-polymerase chain reaction. We also quantified the mRNA levels of these proteins in 14 RCC cases by real-time reverse transcriptase-polymerase chain reaction. RESULTS: HAI-1 and HAI-2 were abundant in the normal kidney. The uriniferous tubules showed the highest levels of HAI-1 and HAI-2 mRNA. HGFA was hardly detectable in the normal kidney. However, in the kidney with RCC a low but distinct level of HGFA mRNA became detectable in the tumor and adjacent renal tissue. The HAI-1 mRNA level was significantly and consistently down-regulated in RCC relative to normal tissue. HAI-2 mRNA was also significantly low in the advanced stage of RCC. MET was up-regulated in most cases of RCC. CONCLUSIONS: HAI-1 and HAI-2 were expressed in renal tubular epithelial cells. The expression of the 2 HAIs was significantly down-regulated in RCC, whereas HGFA expression was enhanced in the diseased kidney, suggesting an imbalance between HAI and its target proteinases, including HGFA, in favor of proteinase activities in RCC.

Carcinoma, Renal Cell↗
PubMed2004

A randomized controlled trial of short-term versus long-term prophylactic intravesical instillation chemotherapy for recurrence after transurethral resection of Ta/T1 transitional cell carcinoma of the bladder.

PURPOSE: In a prospective randomized controlled study, we investigated the optimal schedule for intravesical instillation of epirubicin for maximizing its effect on prophylaxis and disease progression after transurethral resection of newly diagnosed Ta/T1 bladder cancer. MATERIALS AND METHODS: The patients were instilled with epirubicin (30 mg/30 ml in normal saline) within 24 hours after transurethral resection and then randomized into 2 groups after a definite histopathological diagnosis of Ta/T1 bladder cancer. One group of 77 patients received 19 intravesical instillations of epirubicin in the year after transurethral resection (group 1). The second group of 73 patients received 9 intravesical instillations of epirubicin during the 3 months after transurethral resection (group 2). Nonrecurrence rates and toxicity were compared. RESULTS: In the followup period, 10 group 1 patients (13.0%) and 23 group 2 patients (31.5%) had recurrent disease. The 3-year nonrecurrence rate was 85.2% in group 1, whereas it was 63.9% in group 2. The nonrecurrence rate of group 1 was significantly higher than that of group 2 throughout the observation period (p = 0.005). The incidence and severity of toxicity were not significantly different between the 2 groups. CONCLUSIONS: Our study indicates that long-term instillation of epirubicin is more effective than short-term instillation in preventing recurrence after transurethral resection of Ta/T1 bladder cancer.

Administration, Intravesical↗
PubMed2004

Bacteria of preoperative urinary tract infections contaminate the surgical fields and develop surgical site infections in urological operations.

BACKGROUND: The risk factors for surgical site infection (SSI) following urological operations have not been clearly identified, although the presence of a preoperative urinary tract infection (UTI) is thought to be one risk factor. We studied potential risk factors to clarify when and how bacteria contaminate wounds and SSI develop. METHODS: Objects of the present study were patients with SSI after open urological operations that were performed at the Department of Urology, Miyazaki Medical College Hospital, University of Miyazaki, Kiyotake, Miyazaki, Japan, during the period between June 1999 and December 2000. Endourological operations, operations on children and short operations of less than 2 h duration were excluded. Patients were screened for the presence of UTI before the operation and subcutaneous swabs for culture were collected at the end of the operation by brushing with a sterile cotton-swab just before skin closure. RESULTS: Surgical site infections occurred in 20 of 134 patients. Bacteria from the subcutaneous swabs were detected in 15 (75.0%) of the patients with SSI. All patients received antimicrobial prophylaxis (AMP), but bacteria from the subcutaneous swabs of patients with SSI were less susceptible to the agents (20.0%). Preoperative UTI were observed in 11 (55.0%) of the patients with SSI. In these patients, four had the same species of bacteria detected from urine, swab and wound, three had the same species from swab and wound and one had the same species from urine and wound. CONCLUSIONS: Preoperative UTI was the most important risk factor for SSI following urological operations. It is most likely that the bacteria in the urine contaminated the surgical fields and the AMP resistant strains produced SSI.

Adult↗
PubMed2004

Lack of evidence for the association of E-cadherin gene polymorphism with increased risk or progression of prostate cancer.

BACKGROUND: E-cadherin is an epithelial cell adhesion molecule, and decreased E-cadherin expression in human prostate cancer is associated with tumor grade and advanced clinical stage. A -160 C-->A polymorphism in the promoter region of E-cadherin has been shown to decrease gene transcription. This allelic variation may be a potential genetic marker that can help identify those individuals at higher risk for invasive/metastatic disease. MATERIALS AND METHODS: We studied the effect of E-cadherin gene polymorphism on prostate cancer susceptibility in a case control study of 219 prostate cancer patients and 219 male controls, to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is. RESULTS: The genotype frequencies in the prostate cancer group were C/C: 0.607, C/A: 0.352, A/A: 0.041, and in the control group C/C: 0.671, C/A: 0.301, A/A: 0.027. A significant difference between the two groups was not found (p = 0.34), and the adjusted OR for A/A genotype was not statistically significant (OR = 1.66, 95% CI 0.58-4.78). Subdividing prostate cancer according to tumor differentiation and stage, we found no association between E-cadherin polymorphism and poor differentiation and invasiveness of prostate cancer. CONCLUSIONS: These data do not support an association between the E-cadherin genotype and the occurrence or progression of prostate cancer in Japanese populations.

Aged↗
PubMed2003

Cytochrome P450 (CYP) 1A2, sulfotransferase (SULT) 1A1, and N-acetyltransferase (NAT) 2 polymorphisms and susceptibility to urothelial cancer.

PURPOSE: Arylamines are suspected to be the primary causative agent of urothelial cancer in tobacco smoke. In the human liver, arylamines are N-hydroxylated by a cytochrome P450 (CYP)1A2-catalyzed reaction, which produces a substrate for O-esterification that can be catalyzed by N-acetyltransferases (NAT) or sulfotransferases (SULT). Recently, several polymorphisms of CYP1A2, SULT1A1, and NAT2 that affect their activities have been reported. METHODS: In this study, 306 Japanese patients with urothelial transitional cell carcinoma and 306 healthy controls were compared for frequencies of CYP1A2, SULT1A1, and NAT2 genotypes. RESULTS: The frequencies of NAT2 intermediate or slow acetylator genotype were significantly higher in the urothelial cancer patients than in the healthy control subjects [odds ratio (OR) = 1.49, 95% confidence interval (95% CI) 1.06-2.09, OR = 3.23, 95% CI 1.72-6.08, respectively]. Stratifying by amount of smoking, among subjects who consumed >33.5 pack-years and carried the SULT1A1 *1/*1 or NAT2 slow acetylator genotype, the OR was 1.73 (95% CI 1.01-2.97) whereas it was 7.31 (95% CI 1.90-28.05) in non-smokers who carried the homozygous wild genotype, respectively. The relationships between CYP1A2, SULT1A1, and NAT2 polymorphisms and clinical findings including tumor differentiation, stage, and recurrence rate were analyzed. Only associations between NAT2 genotype and pathological findings were admitted, and the higher OR of NAT2 intermediate and slow acetylator genotype was more likely to present to a low-grade tumor (G1) among heavy-smokers. CONCLUSIONS: Our results suggest that SULT1A1 *1/*1 and NAT2 slow acetylator genotypes might modulate the effect of carcinogenic arylamines contained in tobacco smoke, and that the modulation of NAT2 intermediate and slow acetylator genotype has a tendency to present a higher risk for highly differentiated tumors among heavy-smokers.

Aged↗
PubMed2003

E-cadherin gene polymorphism and risk of urothelial cancer.

The E-cadherin is important in cell-cell adhesion and in the development and maintenance of the epithelial phenotype. A -160C-->A polymorphism in the promoter region of E-cadherin has been shown to decrease gene transcription. This allelic variation may be a potential genetic marker that can help identify those individuals at higher risk for invasive/metastatic disease. We studied the effect of E-cadherin gene polymorphism on urothelial cancer susceptibility in a case control study of 314 urothelial cancer patients and 314 age-sex matched controls, to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is. The frequency with which the subjects carried E-cadherin A/A genotype was significantly higher in the urothelial cancer patients than in the healthy control subjects (OR=2.32, 95% CI 1.03-5.22). Subdividing urothelial cancer according to tumor differentiation and stage, we found no association between E-cadherin polymorphism and poorly-differentiation and invasiveness of urothelial cancer. Furthermore, no significant association between E-cadherin polymorphism and recurrence rate of urothelial cancer patients was found. The present study demonstrates for the first time that E-cadherin A/A genotype may be associated with susceptibility to urothelial cancer, but not with the progression of disease.

Adult↗
PubMed2002

Primary adenocarcinoma arising from a paraurethral cyst in a female patient.

A very rare case of primary adenocarcinoma arising from a paraurethral cyst in a 63-year-old woman is reported. Initially she was diagnosed as having a simple paraurethral cyst because of absent communication with the urethra. The resected paraurethral cyst was histologically associated with adenocarcinoma. We also performed chemotherapy composed of methotrexate, vinblastine, Adriamycin and cisplatin because of lymph node metastasis. Our treatment, however, was not effective and the patient died of systemic metastases.

Adenocarcinoma↗
PubMed2002

Expression of hepatocyte growth factor activator inhibitor type 2 (HAI-2) in human testis: identification of a distinct transcription start site for the HAI-2 gene in testis.

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) and type 2 (HAI-2) are recently identified integral membrane Kunitz-type proteinase inhibitors. They have important regulatory roles in pericellular activation of hepatocyte growth factor/scatter factor (HGF/SF) which is critically involved in the development and regeneration of various tissues. Recent reports suggest that HGF/SF is also involved in testicular development and spermatogenesis. In this study, we analyzed the expression of HAIs in the testis. In human testis, HAI-2 was strongly expressed whereas HAI-1 mRNA was hardly detectable. Of interest was the observation that the mRNA size of HAI-2 was shorter in the testis (1.2 kb) than those in the other tissues such as placenta (1.5 kb). Subsequent experiments revealed that there are two major transcription start sites of the HAI-2 gene, which are -30 bp and -360 bp upstream from the translation initiation ATG codon. Although the latter site appeared to be mainly used in the placenta and other non-testicular organs, only the former site is used in testis, resulting in the -300 bp shorter mRNA. An immunohistochemical study using a specific monoclonal antibody raised against human HAI-2 protein indicated that HAI-2 is expressed exclusively in primary spermatocytes. These results suggest a distinct regulation of HAI-2 gene expression in testis and that HAI-2 may play a role in the process of spermatogenesis.

Base Sequence↗