Biomedical subjects

Yutaro Hayashi

Publications and source records attributed to Yutaro Hayashi.

At least 37 records · Page 2Linked to original sources

PubMed2005

Evidence for a relationship between activity and the tetraprotomeric assembly of solubilized pig gastric H/K-ATPase.

Activity-oligomeric assembly relationships using octaethylene glycol dodecyl ether (C12E8) solubilized pig gastric H/K-ATPase (unmodified H/K-ATPase) or H/K-ATPase modified with Fluorescein 5'-isothiocyanate (FITC-H/K-ATPase) were examined. The amount of oligomeric species in FITC-H/K-ATPase, which retained little H/K-ATPase activity was estimated by a single-molecule detection technique using total internal reflection fluorescence microscopy. Solubilization of the FITC-H/K-ATPase reduced the potassium-dependent p-nitrophenyl phosphatase (K-pNPPase) activity to around 5% of the level of the membrane-bound enzyme with the formation of 50% protomer and 40% diprotomer. The solubilization of unmodified H/K-ATPase also reduced both the K-pNPPase and H/K-ATPase activities to around 5%. However, solubilization with increasing concentrations of potassium acetate induced significant and similar increases in K-pNPPase activity (K0.5 = 35 mM) with an increase in the amount of the tetraprotomer of FITC-H/K-ATPase, and the K-pNPPase (K0.5 = 28 mM) and H/K-ATPase (K0.5 = 40 mM) activities of the unmodified H/K-ATPase. The correlation coefficient between the proportion of tetraprotomer and the proportion of the K-pNPPase activity for the same FITC-H/K-ATPase preparation was estimated to be 0.93. Similar coefficients were also obtained between the proportion of tetraprotomer in the FITC-H/K-ATPase and the proportion of K-pNPPase and H/K-ATPase activities in the unmodified H/K-ATPase, with value of 0.85 and 0.86, respectively. Such positive correlations were not obtained between these activities and other oligomeric species. These data, the first direct comparison of oligomeric assembly and enzyme activity both stabilized by K+ in C12E8-solubilized gastric H/K-ATPase, provide strong evidence that the catalytic unit of C12E8-solubilized gastric H/K-ATPase is a tetraprotomer.

4-Nitrophenylphosphatase↗

PubMed2005

Preventive effects of green tea on renal stone formation and the role of oxidative stress in nephrolithiasis.

PURPOSE: Urinary stones are similar to arteriosclerosis in epidemiology, mechanism, calcification composition and age at frequent occurrence. The calcification that occurs in arteriosclerosis is inhibited by antioxidants. Green tea leaves contain approximately 13% catechins, which have been shown to have antioxidant effects. We investigated the inhibitory, antioxidative effects of green tea on calcium urinary stone formation. MATERIALS AND METHODS: A total of 120 Wistar rats were divided into 4 groups, namely group 1-control rats receiving saline, group 2-stone group rats administered ethylene glycol (EG) and vitamin D3, group 3-drink group rats administered EG, vitamin D3 and green tea given as drinking water, and group 4-powder group rats administered EG, vitamin D3 and 2.5% powdered green tea leaves mixed in a powder diet. Pooled 24-hour urine samples and blood samples were collected and the 2 kidneys were excised 7, 14 and 21 days after administration, respectively. One kidney was used for immunohistological examination of osteopontin, superoxide dismutase (SOD), p65, p53 and bcl-2 expression, in situ hybridization of osteopontin and detection of apoptosis, while the other was used for quantitative analysis of SOD activity. RESULTS: Green tea treatment decreased urinary oxalate excretion and calcium oxalate deposit formation. Green tea treatment increased SOD activity compared with the stone group. The degree of apoptosis in the stone group was significantly increased compared with the drink and powder groups. CONCLUSIONS: The inhibitory effect of green tea on calcium oxalate urolithiasis is most likely due to antioxidative effects.

Animals↗

PubMed2005

A polymorphism of the osteopontin gene is related to urinary calcium stones.

PURPOSE: We investigated polymorphisms of the osteopontin (OPN) gene to explore whether they could be used as a gene marker for determining the risk of urinary calcium stones. MATERIALS AND METHODS: A total of 76 patients with urinary calcium stones and 124 controls were studied. Two single nucleotide polymorphisms with nonsynonymous amino acid located at positions 9,402 (Arg/His) and 9,171 (Asn/Ser) in the OPN gene were genotyped using the TaqMan 5' nuclease assay in a PRISM 7700 sequence detection system. Results were analyzed with Fisher's exact test. RESULTS: Results revealed a significant different polymorphism at OPN gene position 9,402 between patients with urinary calcium stones and control subjects. The frequency of the A/G genotype at position 9,402 in patients with urinary calcium stones was significantly higher than that in control subjects (p <0.01). The frequency of the A allele at position 9,402 was significantly higher in the patient than in the control group (4.6% vs 0.4%, p <0.01). There was no statistical difference in this polymorphism at OPN gene position 9,402 between genotype distribution and clinical characteristics associated with urinary calcium stones. There was no difference in the polymorphism at OPN gene position 9,171 between the patient and control groups. CONCLUSIONS: Polymorphism at position 9,402 of the OPN gene is highly associated with urinary calcium stones and it is a candidate genetic marker for evaluating the genetic risk of urinary calcium stone disease, whereas polymorphism at position 9,171 of the OPN gene is not associated with urinary calcium stone disease.

Adult↗

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↗

PubMed2005

Molecular evaluation of the SRY gene for gonads of patients with mixed gonadal dysgenesis.

AIM: To determine whether the SRY gene is present in the gonads of patients with mixed gonadal dysgenesis (MGD). METHODS: Molecular analysis was performed in three patients with MGD. Polymerase chain reactions were used to test for the presence of the SRY gene in the peripheral lymphocytes, testes and streak gonads. RESULTS: Chromosome analysis revealed 45,XO/46,XY in two patients, and 46,XY in the third patient. In the peripheral lymphocytes and testicular tissue, the SRY sequences were positive in all cases. However, the SRY sequence was detected in the streak gonad in only two of the three patients. CONCLUSIONS: It is interesting that we identified both SRY-positive and SRY-negative streak gonads. Although the SRY gene has a very important role in testicular differentiation, genes other than the SRY gene might also influence the development of the indifferent gonad in MGD.

Case-Control Studies↗

PubMed2005

Testicular torsion: usefulness of contrast-enhanced power Doppler sonography.

A 13-year-old-boy with suspected left testicular torsion was referred to our institute. During preparation, a significant decrease of signals on the left testis was found, however, slight blood flow was detected by the ultrasound examination enhanced by Levovist. As a result of the examination we left the testis intact, although the color of the testicular parenchyma remained black. One year after the surgery, an ultrasound examination was done again and good vascurality was observed.

Adolescent↗

PubMed2005

Positive correlation between sialyl Lewis X expression and pathologic findings in renal cell carcinoma.

BACKGROUND: Interaction between tumor cells and endothelium plays a major role in cancer invasion and metastasis. Among various cell adhesion molecules, the cognate interaction between sialyl Lewis antigen expressed in the tumor cell surface and E-selectin expressed on endothelial cells is considered to be crucial for the tumor cell adhesion to the endothelium. METHODS: The sialyl Lewis X (sL(X)) expression in 45 specimens from renal cell carcinoma patients was examined using immunohistochemistry. RESULTS: In this study, we demonstrate that the immunoreactivity for sL(X) in renal cell carcinoma specimens not only correlates with conventional histopathologic parameters but also serves as a useful indicator for the prognosis of renal cell carcinoma. CONCLUSION: Since beneficial effect of cimetidine has been reported and ascribed to its inhibitory action on the expression of E-selectin, a ligand molecule of sialyl Lewis antigen, cimetidine may also show inhibitory effect on the tumor recurrence and metastasis of renal cell carcinoma with high level of sL(X) expression.

Adjuvants, Immunologic↗

PubMed2005

Intermittent pressure-loading increases transforming growth factor-beta-1 secretion from renal tubular epithelial cells: in vitro vesicoureteral reflux model.

BACKGROUND: To investigate the effect of hydrodynamic pressure mimicking vesicoureteral reflux on renal tubular epithelial cells in vitro, we constructed an intermittent pressure-loading (IPL) model of Madin-Darby canine kidney (MDCK) cells. MATERIALS AND METHODS: Three grades of pressure were loaded onto the MDCK cells intermittently. The concentration of cytokines in the supernatant, the amount of the protein and its mRNA in the MDCK cells were studied, respectively. RESULTS: After 24 h, the concentration of transforming growth factor-beta1 (TGF-beta1) increased under intense IPL conditions (100 and 200 cm H2O) in the 15-min IPL group (p<0.05, p<0.01). The amount of cellular level of TGF-beta1 protein and its mRNA did not show any significant increase within 24 h under the present conditions. The concentration of monocyte chemoattractant peptide-1 (MCP-1) was not significantly different from that of the control. CONCLUSION: These data suggest that the early TGF-beta1 secretion phenomenon without change in gene expression is the case in the renal tubular epithelial cells under certain intermittent pressure-loading conditions.

Analysis of Variance↗

PubMed2004

Morphological features of external genitalia in hypospadiac rat model: 3-dimensional analysis.

PURPOSE: We examined 3-dimensionally the process of external genitalia formation in the experimental hypospadiac rat model. MATERIALS AND METHODS: We administered 7.5 mg flutamide daily, a blocker of androgen receptor, into the abdomen of naturally pregnant female Sprague-Dawley rats from gestational days 14 to 20 to produce a hypospadiac rat model. The control group consisted of male offspring not exposed to flutamide. The fetal phallus was obtained at gestational days 17.5, 19.5 and 21.5. We observed them by scanning electron microscopy. RESULTS: In the 17.5-day-old embryo the projection on the ventral side of the phallus was observed from the base of the phallus to the coronary sulcus in the control rat. This finding demonstrated that the urethra develops from the base of the phallus to the coronary sulcus. On the other hand, this projection was not observed in the hypospadiac rat and the urethra was not seen on the ventral side of the phallus. In the 19.5-day-old embryo the ventral preputial closure appeared in the proximal phallus of the control rat but not of the hypospadiac rat. In the control rat the scrotum was discerned in the perineum and divided by a median fold (the raphe). The raphe reached the base of the phallus, where it was concurrent with the preputial fold that covers the urethra. On the other hand, the hypospadiac rat did not have a raphe and the hollow at the base of the phallus appeared to give rise to the future orifice of the urethra. In the 21.5-day-old embryo the control rat prepuce completely surrounded the distal phallus, whereas that of the hypospadiac rat was dorsally hooded with a ventral cleft and the external appearance resembled the morphology of human penoscrotal hypospadias. CONCLUSIONS: This hypospadiac rat model is considered valuable for further studying penile growth and differentiation, and the molecular mechanisms in external genitalia formation in hypospadias.

Animals↗

PubMed2003

Correlation between the activities and the oligomeric forms of pig gastric H/K-ATPase.

Membrane-bound H/K-ATPase was solubilized by octaethylene glycol dodecyl ether (C(12)E(8)) or n-octyl glucoside (nOG). H/K-ATPase activity and the distribution of protomeric and oligomeric components were evaluated by high-performance gel chromatography (HPGC) and by single-molecule detection using total internal reflection fluorescence microscopy (TIRFM). As evidenced by HPGC of the C(12)E(8)-solubilized enzyme, the distribution of oligomers was 12% higher oligomeric, 44% diprotomeric, and 44% protomeric species, although solubilization by C(12)E(8) reduced the H/K-ATPase activity to 1.8% of that of the membrane-bound enzyme. The electron microscopic images of the C(12)E(8)-solubilized enzyme showed the presence of protomers and a combination of two and more protomers. While the nOG-solubilized H/K-ATPase retained the same turnover number and 71% of the specific activity as that of the membrane-bound enzyme, 56% higher oligomeric, 34% diprotomeric, and 10% protomeric species were detected. TIRFM analysis of solubilized fluorescein 5'-isothiocyanate (FITC)-modified H/K-ATPase at Lys-518 of the alpha-chain showed a quantized photobleaching of the FITC fluorescence intensity. For the C(12)E(8)-solubilized FITC-enzyme, the fraction of each of the initial relative fluorescence intensity units of 4, 2, and 1 was, respectively, 5%, 44% and 51%. In the case of the nOG-solubilized FITC-enzyme, each fraction of 4 and 2 units was, respectively, 54% and 46% with no detectable 1 unit fraction. This represents the first direct observation of H/K-ATPase in aqueous solution. The correlation between the enzymatic activities and distribution of oligomeric forms of H/K-ATPase by HPGC and the observation of a single molecule of H/K-ATPase and others suggests that the tetraprotomeric form of H/K-ATPase molecules represents the functional species in the membrane.

Animals↗

PubMed2003

Gold compounds inhibit adhesion of human cancer cells to vascular endothelial cells.

Transcription factor NF-kappaB controls the expression of a number of genes including those for cell adhesion molecules such as E-selectin, ICAM-1 and VCAM-1. These cell adhesion molecules are known to play important roles in a critical step of tumor metastasis; the arrest of tumor cells on the venous or capillary bed of the target organ. NF-kappaB is activated by extracellular signals such as those elicited by the proinflammatory cytokines, TNF and IL-1. Here we demonstrate that IL-1beta induces nuclear translocation of NF-kappaB in human umbilical vein endothelial cells (HUVEC) followed by induction of cell surface expression of E-selectin, ICAM-1 and VCAM-1, and subsequently augments adhesion of cancer cells expressing sialyl Lewis antigen, a ligand of E-selectin. We also demonstrated that the adhesion of tumor cells to IL-1beta-treated HUVEC was inhibited by gold compounds such as aurothioglucose and aurothiomalate. These observations indicate the involvement of NF-kappaB in cancer metastasis and suggest the feasibility of using gold compounds to prevent metastasis.

Cell Adhesion↗

PubMed2003

Clinical characteristics of primary vesicoureteral reflux in infants: multicenter retrospective study in Japan.

PURPOSE: We evaluate clinical characteristics of primary vesicoureteral reflux in infants in a multicenter study in Japan with special reference to the relation of renal parenchymal damage to urinary tract infection and gender. MATERIALS AND METHODS: Infants younger than 1 year old with primary vesicoureteral reflux were recruited from 14 hospitals during the 3-year registration period beginning in January 1996 and ending in December 1998. Various clinical parameters as well as renal parenchymal lesion on dimercaptosuccinic acid scintigraphy were evaluated. RESULTS: Of 356 infants enrolled 296 (83%) were male and 60 (17%) were female. In 85% of infants presenting symptom was febrile urinary tract infection. There were 204 bilateral (57%) and 152 unilateral (43%) cases. Reflux was bilateral in 56% of males versus 65% of females, and high grade (grades IV and V) in 58% of males versus 55% of females. Diffuse parenchymal lesion was similarly noted in infants with or without prior urinary tract infection (38% and 46%, respectively) and was more often noted in male than in female infants (42% versus 25%). CONCLUSIONS: Despite the current use of screening prenatal ultrasound, many infants are still diagnosed as having vesicoureteral reflux only after the occurrence of urinary tract infection. The greater severity of renal parenchymal lesion in male infants combined with similar incidence of diffuse parenchymal lesion in those with or without prior infection suggests preexisting congenital abnormalities in the male refluxing kidney.

Female↗

PubMed2003

A strategy for repairing moderately severe hypospadias using onlay urethroplasty versus onlay-tube-onlay urethroplasty.

OBJECTIVES: Moderately severe hypospadias can be repaired by a simple onlay island flap procedure with penile dorsal plication in most patients. However, when the penile curvature could not be corrected, and the urethral plate could not be preserved by the procedure, a combined procedure of onlay and tubularized island flap is subsequently needed. METHODS: Onlay urethroplasty was performed to repair hypospadias in 39 patients with hypospadias. However, the combined procedure (onlay-tube-onlay urethroplasty) was performed on 6 patients who had severe penile curvature even after skin degloving. RESULTS: Hypospadias was repaired successfully without complications in 30 (90.9%) of the 33 patients by conventional onlay urethroplasty alone. Of the 6 patients who underwent onlay-tube-onlay urethroplasty, 1 patient developed fistula and 1 developed meatal stenosis, for a success rate of 66.7%. The complications in all patients were later resolved. CONCLUSIONS: We recommend switching to onlay-tube-onlay urethroplasty when the attempt to repair moderately severe hypospadias by the simple onlay procedure has to be abandoned, and the urethral plate needs to be divided.

Humans↗

PubMed2003

Leiomyoma of the urinary bladder during pregnancy.

We present a rare case of leiomyoma of the urinary bladder that was diagnosed during pregnancy. To our knowledge, this is the fourth case of its kind to be reported in the literature. Ultrasonography, magnetic resonance imaging and biopsy were useful for making an accurate diagnosis in this case. The diagnosis was confirmed by suprapubic transcutaneous needle biopsy. The tumor was resected approximately 3 years after diagnosis, during which period the patient delivered a normal baby by caesarian section.

Abdominal Pain↗