Yutaro Hayashi

Fukushima Medical University, Hukusima, Fukushima, Japan

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Publications (228)545.23 Total impact

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    ABSTRACT: Laparoscopic extravesical ureteral reimplantation for vesicoureteral reflux has gained acceptance as a feasible treatment associated with minimal morbidity. However, ureteral advancement with this technique has not been attempted. We examined the usefulness of ureteral advancement via laparoscopy. A total of 30 patients with 51 refluxing ureters underwent laparoscopic extravesical ureteral reimplantation for treatment of vesicoureteral reflux between August 2009 and September 2011. Mean ± SD patient age was 60.8 ± 48.6 months. During the procedure 15 patients underwent ureteral advancement (advancement group), while 15 did not (nonadvancement group). We compared operative times and postoperative rates of urinary tract infections and persistent reflux between the groups. There was no significant difference in operative times in unilateral (mean ± SD 110 ± 25 vs 125 ± 42 minutes) and bilateral cases (mean ± SD 214 ± 52 vs 203 ± 40 minutes) between the nonadvancement vs advancement groups. All patients underwent voiding cystourethrography 3 to 4 months postoperatively. Reflux resolution rate for ureters was significantly higher in the advancement group (100%) than in the nonadvancement group (85%, p <0.05). No patient in the advancement group had postoperative urinary tract infection. Fixation of the ureter with the bladder muscularis at the proximal limit of the detrusor defect and/or a percutaneous hitch stitch placed in the ventral side of the proximal limit of the detrusor defect facilitated ureteral advancement. Ureteral advancement is a simple and feasible procedure in laparoscopic ureteral extravesical reimplantation and may improve the resolution rate of vesicoureteral reflux.
    The Journal of urology 06/2012; 188(2):582-7. DOI:10.1016/j.juro.2012.04.018 · 3.75 Impact Factor
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    ABSTRACT: Caudal regression syndrome (CRS) is a rare congenital vertebral anomaly, which occurs most often in combination with spinal cord malformations and morphologic dysfunctions of the lower extremities; these signs are useful for both patients and clinicians in the diagnosis of this syndrome. However, in certain cases, clinicians have failed to identify the syndrome due to the lack of apparent anomalies, resulting in the progression of renal dysfunction caused by neuropathic bladder when CRS is eventually identified. Here, we report a case of a 2-year-old girl who was referred to our hospital for vesicoureteral reflux. At examination, she presented no neurological symptoms; however, on cystourethrography and CT scanning we found that the sacral bone was absent, through which CRS was diagnosed. A urodynamic study indicated detrusor-sphincter dyssynergia, and clean intermittent catheterization was initiated. In the present report, we describe a case of CRS with no neurologic symptoms other than a neuropathic bladder. The lack of outward signs can result in delayed diagnosis. Thus, urological examinations, including a urodynamic study, might be the only clue for identifying an underlying neurologic injury involving the lower spinal cord.
    Case Reports in Medicine 06/2012; 2012:982418. DOI:10.1155/2012/982418
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    ABSTRACT: We hypothesized that single-nucleotide polymorphisms (SNPs) of genes involved in environmental endocrine disruptors (EEDs) metabolism might influence the risk of male genital malformations. In this study, we explored for association between 384 SNPs in 15 genes (AHR, AHRR, ARNT, ARNT2, NR1I2, RXRA, RXRB, RXRG, CYP1A1, CYP1A2, CYP1B1, CYP2B6, CYP3A4, CYP17A1 and CYP19A1) and risk of cryptorchidism (CO) and hypospadias (HS) in 334 Japanese (JPN) males (141 controls, 95 CO and 98 HS) and 187 Italian (ITA) males (129 controls and 58 CO). In the JPN study group, five SNPs from ARNT2 (rs2278705 and rs5000770), CYP1A2 (rs2069521), CYP17A1 (rs4919686) and NR1I2 (rs2472680) were significantly associated at both allelic and genotypic levels with risk of at least one genital malformation phenotype. In the ITA study group, two SNPs in AHR (rs3757824) and ARNT2 (rs1020397) were significantly associated with risk of CO. Interaction analysis of the positive SNPs using multifactor dimensionality reduction demonstrated that synergistic interaction between rs2472680, rs4919686 and rs5000770 had 62.81% prediction accuracy for CO (P=0.011) and that between rs2069521 and rs2278705 had 69.98% prediction accuracy for HS (P=0.001) in JPN population. In a combined analysis of JPN and ITA population, the most significant multi-locus association was observed between rs5000770 and rs3757824, which had 65.70% prediction accuracy for CO (P=0.055). Our findings indicate that genetic polymorphisms in genes involved in EED metabolism are associated with risk of CO and HS.
    Journal of Human Genetics 05/2012; 57(7):434-41. DOI:10.1038/jhg.2012.48 · 2.53 Impact Factor
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    ABSTRACT: The effect of low-dose bisphenol A (BPA) exposure on human reproductive health is still controversial. To better understand the molecular basis of the effect of BPA on human reproductive health, a genome-wide screen was performed using human foreskin fibroblast cells (hFFCs) derived from child hypospadias (HS) patients to identify novel targets of low-dose BPA exposure. Gene expression profiles of hFFCs were measured after exposure to 10 nM BPA, 0.01 nM 17β-estradiol (E2) or 1 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 24 h. Differentially expressed genes were identified using an unpaired Student's t test with P value cut off at 0.05 and fold change of more than 1.2. These genes were selected for network generation and pathway analysis using Ingenuity Pathways Analysis, Pathway Express and KegArray. Seventy-one genes (42 downregulated and 29 upregulated) were identified as significantly differentially expressed in response to BPA, among which 43 genes were found to be affected exclusively by BPA compared with E2 and TCDD. Of particular interest, real-time PCR analysis revealed that the expression of matrix metallopeptidase 11 (MMP11), a well-known effector of development and normal physiology, was found to be inhibited by BPA (0.47-fold and 0.37-fold at 10 nM and 100 nM, respectively). Furthermore, study of hFFCs derived from HS and cryptorchidism (CO) patients (n = 23 and 11, respectively) indicated that MMP11 expression was significantly lower in the HS group than in the CO group (0.25-fold, P = 0.0027). This present study suggests that an involvement of BPA in the etiology of HS might be associated with the downregulation of MMP11. Further study to elucidate the function of the novel target genes identified in this study during genital tubercle development might increase our knowledge of the effects of low-dose BPA exposure on human reproductive health.
    PLoS ONE 05/2012; 7(5):e36711. DOI:10.1371/journal.pone.0036711 · 3.53 Impact Factor
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    ABSTRACT: We report the case of a newborn infant with cloacal exstrophy. On the 16th day after birth, complete primary exstrophy repair was performed. The bladder tissue obtained during surgery contained collagen tissue and a little smooth muscle, as well as a few neuron cells and kit-positive interstitial cells in the submucosal layer. This is the first report of a histopathologic analysis of the bladder tissue in cloacal exstrophy. We also discuss the influence of the pathologic changes on bladder dysfunction.
    Urology 04/2012; 79(6):1368-71. DOI:10.1016/j.urology.2011.09.020 · 2.13 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e108. DOI:10.1016/j.juro.2012.02.323 · 3.75 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e636. DOI:10.1016/j.juro.2012.02.1341 · 3.75 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e650. DOI:10.1016/j.juro.2012.02.1401 · 3.75 Impact Factor
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    ABSTRACT: Renal tubular cell injury induced by oxidative stress via mitochondrial collapse is thought to be the initial process of renal calcium crystallization. Mitochondrial collapse is generally caused by mitochondrial permeability transition pore (mPTP) opening, which can be blocked by cyclosporine A (CsA). Definitive evidence for the involvement of mPTP opening in the initial process of renal calcium crystallization, however, is lacking. In this study, we examined the physiological role of mPTP opening in renal calcium crystallization in vitro and in vivo. In the in vitro study, cultured renal tubular cells were exposed to calcium oxalate monohydrate (COM) crystals and treated with CsA (2 μM). COM crystals induced depolarization of the mitochondrial membrane potential and generated oxidative stress as evaluated by Cu-Zn SOD and 4-HNE. Furthermore, the expression of cytochrome c and cleaved caspase 3 was increased and these effects were prevented by CsA. In the in vivo study, Sprague-Dawley rats were administered 1% ethylene glycol (EG) to generate a rat kidney stone model and then treated with CsA (2.5, 5.0, and 10.0 mg/kg/day) for 14 days. EG administration induced renal calcium crystallization, which was prevented by CsA. Mitochondrial collapse was demonstrated by transmission electron microscopy, and oxidative stress was evaluated by measuring Cu-Zn SOD, MDA, and 8-OHdG generated by EG administration, all of which were prevented by CsA. Collectively, our results provide compelling evidence for a role of mPTP opening and its associated mitochondrial collapse, oxidative stress, and activation of the apoptotic pathway in the initial process of renal calcium crystallization.
    Free Radical Biology and Medicine 04/2012; 52(7):1207-17. DOI:10.1016/j.freeradbiomed.2012.01.005 · 5.71 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e637. DOI:10.1016/j.juro.2012.02.1345 · 3.75 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e556-e557. DOI:10.1016/j.juro.2012.02.1755 · 3.75 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e844. DOI:10.1016/j.juro.2012.02.2261 · 3.75 Impact Factor
  • The Journal of Urology 04/2012; 187(4):e636-e637. DOI:10.1016/j.juro.2012.02.1343 · 3.75 Impact Factor
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    ABSTRACT: Laparoendoscopic single-site surgery (LESS), a minimally invasive procedure, is gaining widespread acknowledgment in pediatric urology. We report the case of a 7-year-old girl with Turner's syndrome with 45,XO/46,XY mosaicism, for whom bilateral prophylactic gonadectomy using LESS was performed. Histopathological findings revealed bilateral streak gonads. The surgical and cosmetic outcome was excellent. Diagnostic and therapeutic laparoscopy is essential for accurate clinical management of patients with disorders of sex development. Although this is only a single case report, it supports the theory that LESS is an exceedingly practical and superior technique for such children, since it provides excellent magnification, as well as allowing normal psychological development owing to the concealed scar. Further studies and long-term follow-up are required to evaluate the benefits and limitations of applying LESS in pediatrics.
    Journal of pediatric urology 03/2012; 8(4):e39-42. DOI:10.1016/j.jpurol.2012.02.010 · 1.41 Impact Factor
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    ABSTRACT: To elucidate the mechanism of infertility caused by cryptorchidism we focused on early stage spermatogenesis and spermatogonial stem cell activity in undifferentiated spermatogonia in cryptorchid testes. Histological findings and expression patterns of the stem cell marker undifferentiated embryonic cell transcription factor 1 were examined in a unilateral cryptorchid rat model. We removed unilateral descended testis and contralateral descended testis from cryptorchid and normal rats (control), respectively, 18 days postcoitum to 144 days postpartum. In descended testes gonocyte differentiation into early A spermatogonia occurred at 9 days postpartum. However, this transformation was altered in undescended testes. Furthermore, the undifferentiated embryonic cell transcription factor 1 negative early A spermatogonia-to-positive early A spermatogonia ratio was significantly higher in the undescended testis group (mean ± SD 0.69 ± 0.04) than in the control (0.46 ± 0.10, p = 0.037) and descended testis (0.44 ± 0.05, p = 0.022) groups, indicating decreased early A spermatogonia with spermatogonial stem cell activity in cryptorchid testes. In cryptorchid testes the differentiation from gonocytes into early A spermatogonia and the stem cell activity of early A spermatogonia were altered during the early stage of spermatogenesis, suggesting that the loss of spermatogonial stem cell activity in cryptorchid rats resulted in altered spermatogenesis, thus interfering with fertility.
    The Journal of urology 03/2012; 187(3):1047-52. DOI:10.1016/j.juro.2011.10.170 · 3.75 Impact Factor
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    ABSTRACT: To identify the causes of vanishing testis besides vascular events secondary to testicular torsion. A total of 102 boys with vanishing testis were treated in our hospital from 1984 to 2011. Of these cases, 91 testicular nubbins were excised. Immunohistochemical analysis of testicular nubbins was carried out using anti-Wilms tumor 1 antibody, which is a stable marker of Sertoli cells. Reverse transcription polymerase chain reaction was also carried out using Wilms tumor 1-specific primers. Most testicular nubbins were associated with inguinal lesion (51 patients, 56.0%). Light microscopy showed that 11 patients (12.5%) had seminiferous tubules (with germ cells in three patients [3.4%]), and 77 patients lacked seminiferous tubules, some of which had calcification (26 patients, 29.5%), and/or deposition of hemosiderin (21 patients, 23.9%). Immunohistochemical analysis showed Wilms tumor 1 expression not only in the Sertoli cells of the seminiferous tubules in the seminiferous tubule-positive patients, but also in the interstitium of testicular nubbins in the seminiferous tubule-negative patients. Reverse transcription polymerase chain reaction showed Wilms tumor 1 messenger ribonucleic acid expression in the testicular nubbins of both seminiferous tubule-positive and tubule-negative patients. The presence of Wilms tumor 1-positive cells in the interstitium of vanishing testis lacking seminiferous tubules suggests that the disturbance of testicular development after Sertoli cell differentiation and during testicular tubule formation might be involved in the etiology of vanishing testis.
    International Journal of Urology 01/2012; 19(5):450-6. DOI:10.1111/j.1442-2042.2011.02951.x · 1.80 Impact Factor
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    ABSTRACT: The effects of tamsulosin treatment on changes in frequency-volume chart (FVC) data, especially nighttime urine production, over time were assessed, and the mechanisms underlying the improvement of nocturia in benign prostatic hyperplasia (BPH) patients with nocturnal polyuria (NP) are discussed. A total of 104 patients with lower urinary tract symptoms secondary to BPH were enrolled. After enrollment in the study, the patients were treated with tamsulosin (0.2 mg) once daily. Visits were scheduled every 4 weeks until week 12 (month 3) after study entry, and then every 12 weeks subsequently. All patients completed the International Prostate Symptom Score (IPSS), quality of life (QOL) index, and 3-day FVC, and underwent uroflowmetry at enrollment and on each visit. Eighty-two patients (mean age: 70.9 ± 7.1 years) were analyzed for 24 months after treatment. Patients were divided into two groups, NP and nonNP, based on FVC outcome. The IPSS, QOL index, and maximum flow rate improved during the 24-month period after treatment in both groups. Mean daytime urine volume significantly increased in the NP group, but no changes were detected in the nonNP group. Mean nighttime urine frequency significantly decreased in the NP group over a 24-month period, and was associated with a significant decrease in nighttime urine volume that was not found in the nonNP group. Maximum voided volume increased most months after treatment in both groups. The present long-term prospective study using FVC demonstrated that tamsulosin reduced nighttime urine production in BPH patients with NP.
    Neurourology and Urodynamics 01/2012; 31(1):80-5. DOI:10.1002/nau.21224 · 2.46 Impact Factor
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    ABSTRACT: Kallmann syndrome (KS) is a genetic disorder characterized by the simultaneous occurrence of idiopathic hypogonadotropic hypogonadism (IHH) and anosmia. Here, we present 3 cases of KS with detailed description. In Case 1, testicular morphology was examined by testicular biopsy, and Leydig cells were examined by immunohistochemistry using antibodies against Ad4BP/SF1. Contrary to our predictions, the present study revealed the presence of Leydig cells in the testis. Testicular morphology in the patients with KS is more varied than expected, and further investigation is required to elucidate hormonal effects on normal testicular development.
    Urology 12/2011; 79(3):684-6. DOI:10.1016/j.urology.2011.10.032 · 2.13 Impact Factor
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    ABSTRACT: Osteopontin plays a crucial role in the formation of renal calcium crystals, which are primarily induced by renal tubular cell injury, especially mitochondrial damage. We have previously shown that the impaired Arg-Gly-Asp (RGD) sequence of osteopontin inhibits renal crystal formation by using OPN-transgenic mice and OPN-knockout (OPN-KO) mice. Here, we investigated the effects of an antimurine osteopontin antibody (35B6-Ab) that specifically reacts with the (162) SLAYGLR(168) sequence, which is exposed by thrombin cleavage and is located adjacent to the RGD sequence, on renal crystal formation. Renal crystals induced by daily administration of glyoxylate over 9 days (from days 1 to 9) in a murine model were sporadically detected in the renal tubular cells at the corticomedullary junction, where thrombin-cleaved osteopontin expression was also coincidentally detected. On days 0, 3, 6, and 9, 35B6-Ab administration inhibited renal crystal formation and induced significant morphological changes in a dose-dependent manner (250, 500, and 1000 µg per mouse). Scanning electron microscopy showed that the crystals in 35B6-Ab-treated mice were aberrantly formed and their density was low; in contrast, the crystals in untreated mice that were not administered 35B6-Ab had a radial pattern of growth (rosette petal-like crystals), and their density was high. Microstructure analysis of renal tubular cells by transmission electron microscopy revealed that untreated mice showed collapsed mitochondria in the flattened cytoplasm of renal tubular cells, unlike the corresponding structures in 35B6-Ab-treated mice, in which renal tubular cell injury was inhibited. In vitro, 35B6-Ab was found to inhibit the attachment of (14) C-labeled crystals to renal tubular culture cells and reduce morphological damage to these cells. We conclude that thrombin-cleaved osteopontin plays an important role in formation of renal calcium crystals and that 35B6-Ab contributes to the remarkable inhibition of early-stage renal crystal formation by preventing renal tubular cell injury and crystal-cell attachment.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 12/2011; 26(12):2967-77. DOI:10.1002/jbmr.495 · 6.59 Impact Factor
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    ABSTRACT: To investigate the molecular aetiology of hypospadias during a critical developmental period by identifying differentially regulated genes in the tissues of individuals with hypospadias and comparing these genes with similar genes in the tissues of control individuals. Pregnant Sprague-Dawley rats were administered flutamide (7.5 mg) on gestational days 15-17 to produce hypospadiac pups. Dams were killed on gestational day 17, and the genital tubercles (GTs) of male pups were harvested. Gene expression of RNA isolated from the GTs was analysed using an oligonucleotide microarray containing 20,500 genes. The results of microarray analysis were confirmed using quantitative real-time PCR (qPCR). Protein expression levels were studied using Western blot analysis. The distribution of genes associated with GT development in rats was histologically examined. Prepuces harvested from patients with hypospadias and phimosis were immunohistochemically examined for gene distribution. Of the 20, 500 genes, 23 annotated genes, including prolactin-induced protein (Pip), in the GTs of the hypospadiac rats were expressed at levels less than half of that of similar genes in the GTs of the control rats. Findings from qPCR and Western blot analysis revealed significantly lower Pip/PIP expression in the GTs of the hypospadiac rats than in those of the control rats. Immunohistochemical analysis revealed PIP expression in the prepuces of the GTs of the control and hypospadiac rats. PIP was expressed in the human prepuces of the patients with hypospadias and phimosis. Pip/PIP, expressed at low levels in the GTs of hypospadiac rats, may be associated with preputial development. This model can be useful to elucidate the molecular mechanisms underlying penile and urethral development as well as preputial development. Further studies should provide detailed information regarding the molecular aetiology of hypospadias.
    BJU International 08/2011; 109(6):926-32. DOI:10.1111/j.1464-410X.2011.10467.x · 3.13 Impact Factor

Publication Stats

1k Citations
545.23 Total Impact Points


  • 2014
    • Fukushima Medical University
      Hukusima, Fukushima, Japan
  • 1995–2014
    • Nagoya City University
      • • Department of Nephro-urology
      • • Department of Radiology
      • • Division of Nephrologyogy
      • • Department of Urology
      Nagoya, Aichi, Japan
  • 2009
    • Central Bank of the Islamic Republic of Iran
      Teheran, Tehrān, Iran