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Biomedical subjects

Shuichi Sato

Publications and source records attributed to Shuichi Sato.

At least 19 recordsLinked to original sources
PubMed2006

Effect of tamsulosin on spontaneous bladder contraction in conscious rats with bladder outlet obstruction: comparison with effect on intraurethral pressure.

We investigated the effect of tamsulosin, an alpha(1)-adrenoceptor antagonist, on bladder function, especially spontaneous bladder contractions before micturition (premicturition contraction), in conscious rats with bladder outlet obstruction induced by partial urethral ligation, and compared the results with the effect on intraurethral pressure response in anesthetized rats. In obstructed rats, the alpha(1)-adrenoceptor antagonists tamsulosin, naftopidil and urapidil and non-selective alpha-adrenoceptor antagonist phentolamine inhibited premicturition contractions in a dose-dependent fashion. In contrast, yohimbine, an alpha(2)-adrenoceptor antagonist, and atropine, a muscarinic receptor antagonist, hardly inhibited them. Tamsulosin and urapidil showed clearly inhibitory effects on increases in intraurethral pressure induced by phenylephrine, an alpha(1)-adrenoceptor agonist, in the same dose range as that at which they inhibited premicturition contractions, whereas naftopidil required somewhat higher doses to inhibit increases in intraurethral pressure than those at which it inhibited premicturition contractions. In conclusion, premicturition contractions observed in obstructed rats were sensitive to alpha(1)-adrenoceptor antagonists, but not to alpha(2)-adrenoceptor or muscarinic receptor antagonists. Tamsulosin was shown to be effective against both premicturition contraction and intraurethral pressure response in the same dose range in rats. These results partly support the fact that tamsulosin has improved storage symptoms as well as voiding symptoms in patients with lower urinary tract symptoms associated with bladder outlet obstruction by blocking alpha(1)-adrenoceptors.

Animals↗
PubMed2006

Participation of endogenous endothelin and ETA receptor in premicturition contractions in rats with bladder outlet obstruction.

A relationship between endogenous endothelins and bladder overactivity has recently been suggested, but the related endothelin receptor subtype has not been identified. Here, to evaluate the involvement of endothelin-1 and its receptors in bladder overactivity, we investigated endothelin-1 levels and the expression of its receptors in the bladder of rats with bladder outlet obstruction (BOO), a model for bladder overactivity. We also investigated the effects of a selective endothelin ET(A) receptor antagonist, (E)-N-[6-methoxy-5-(2-methoxyphenoxy)[2,2'-bipyrimidin]-4-yl]-2-phenylethenesulfonamide monopotassium salt (YM598), on bladder functions in conscious BOO rats. Partial obstruction of the urethra led to a progressive increase in bladder weight from weeks 1 to 6. Binding assays performed using plasma membranes prepared from these bladders to estimate endothelin receptor density from the maximum [(125)I]endothelin-1 binding showed increased endothelin receptor density (about double) at 1, 2, and 6 weeks after the operation in the BOO bladder. The densities of endothelin ET(A) receptors in the bladder of sham-operated and BOO rats at 2 weeks after operation were about 3.5 and 5 times those of endothelin ET(B) receptors respectively. Furthermore, the endothelin-1 level was also increased in the BOO bladder. Two weeks after operation, BOO rats showed an increase in maximum bladder capacity and micturition volume and the generation of premicturition contractions. The frequency of premicturition contractions was dose-dependently reduced by YM598 (0.1-3 mg/kg, i.v.) without any effect on other voiding parameters in BOO rats. These data suggest that endothelin-1 and endothelin ET(A) receptors might be involved in the generation of premicturition contractions in BOO rats, and that endothelin ET(A) receptor antagonists such as YM598 may have ameliorating effects in patients with bladder overactivity associated with BOO.

Animals↗
PubMed2006

Bite force and occlusal contact area changes following mandibular widening using distraction osteogenesis.

OBJECTIVE: To examine changes in bite force and occlusal contact area after mandibular widening by distraction osteogenesis using pressure-sensitive sheet (Dental-Prescale; Fuji Photo Film, Tokyo, Japan). STUDY DESIGN: Fifteen patients with transverse mandibular deficiency (6 to 9 mm, mean distraction interval: 8 mm) were examined. They were measured just before the operation and at 1 week, 1 month, 3 months, 6 months, and 1 year after the operation. Ten control subjects with normal occlusion were also measured. RESULTS: Both bite force and occlusal contact area were lowest at 1 month postoperatively. The values of bite force and occlusal contact area steadily increased thereafter. The bite force and occlusal contact area reached to the preoperative levels at 6 months after operation and slightly above the preoperative level at 12 months after operation. There were no statistically significant differences between 12 months and the control values for bite force measurements (P > .05). CONCLUSION: Although statistically not significant, this study suggests that mandibular symphyseal distraction osteogenesis increases the bite force and occlusal contact area in patients with transverse mandibular deficiency.

Adolescent↗
PubMed2006

Quantitative measurement of hepatitis B virus DNA in different areas of hepatic lobules in patients with chronic hepatitis B.

Liver histology in chronic hepatitis B is marked by inflammatory infiltration involving the peripheral zones. The cause of such cellular infiltration remains unknown. The aim of the present study was to investigate the amounts of intrahepatic hepatitis B virus (HBV) DNA separately in the peripheral and central zones, using laser capture microdissection coupled with real-time quantitative polymerase chain reaction. Fourteen patients with chronic hepatitis B were included in the study. Liver biopsy samples were taken and hepatocytes were microdissected separately from peripheral and central zones. DNA was extracted from hepatocytes in each zone and evaluated the amounts of HBV-DNA. Immunohistochemical study for hepatitis B core antigen (HBcAg) was also performed. The amounts of total intrahepatic HBV-DNA in patients positive for hepatitis Be antigen (HBeAg) were greater than those in HBeAg-negative patients. There was no difference in HBV-DNA between the peripheral and central zones. Immunohistochemistry also showed that HBcAg-positive cells were distributed homogeneously in the hepatic lobules. In patients with peripherally predominant HBV-DNA, the serum alanine aminotransferase (ALT) level was lower than in patients with centrally predominant HBV-DNA. HBV-DNA was distributed homogeneously in the hepatic lobules. In patients with lower amounts of HBV-DNA in the peripheral zone, the serum ALT level tended to be higher than in other patients.

Adult↗
PubMed2006

A Japanese case of eosinophilic esophagitis.

Eosinophilic esophagitis (EE) is a rarely diagnosed condition involving eosinophilic infiltration of the esophageal mucosa. Here we present a case of EE in a 69-year-old Japanese man, who presented with abdominal pain, appetite loss, and a history of bronchial asthma. Laboratory findings included peripheral eosinophilia and an increased serum immunoglobulin E level. Computed tomography showed diffuse severe thickening of the esophageal wall, and a barium esophagogram revealed a small caliber of the middle and lower portion of the esophagus, without normal peristaltic contractions. Endoscopy of the esophagus showed a pale mucosa, with adherent whitish exudates resembling fungal infection, and prominent ring-like contractions. Histologic examination of a biopsy specimen revealed marked eosinophil infiltration into the esophageal mucosa. Endoscopic ultrasonography (EUS) demonstrated marked circumferential thickening of the esophageal submucosal layer, and an esophageal manometry study showed a high percentage of ineffective esophageal peristalsis and high-amplitude esophageal body contractions. EUS findings showed no change even after oral corticosteroid therapy, although the histological findings were improved. This is thought to be the first documented Japanese case of EE. EE should be considered in the differential diagnosis in cases of esophageal motility disturbance, even if the patients do not complain of dysphagia.

Aged↗
PubMed2006

Influence of acid suppressants on gastric emptying: cross-over analysis in healthy volunteers.

BACKGROUND: Gastric emptying plays an important role in gastroesophageal reflux disease. Acid suppressants such as H2 receptor antagonists and/or proton pump inhibitors are often used in patients with gastroesophageal reflux disease. However, it remains controversial whether H2 receptor antagonists and proton pump inhibitors delay or accelerate gastric emptying. Here, the influence of acid suppressants on gastric emptying was evaluated via a cross-over study using the [13C]-labeled acetate breath test. METHODS: Twenty normal male subjects without gastroesophageal reflux disease symptoms were enrolled. Gastric emptying was investigated five times in every subject by the [13C]-labeled acetate breath test with oral administration of the vehicle, domperidone, and three acid suppressants: ranitidine, famotidine and rabeprazole. Gastric emptying was estimated by the values of T(max-calc), T(1/2) and %dose/2 h calculated from the 13CO2 breath excretion curve. RESULTS: Using the T(max-calc) values, rabeprazole, ranitidine and famotidine did not influence gastric emptying time in comparison with vehicle administration. Using the T(1/2) and %dose/2 h values, rabeprazole tended to delay gastric emptying. Domperidone produced a statistically significant acceleration of gastric emptying for all three variables (P < 0.05). CONCLUSION: Oral dosage of the H2 receptor antagonists, ranitidine and famotidine, has no significant effect on gastric emptying. However, rabeprazole may delay gastric emptying more strongly than H2 receptor antagonists.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2006

Kinetics of indocyanine green removal from blood can be used to predict the size of the area removed by radiofrequency ablation of hepatic nodules.

BACKGROUND AND AIM: The size of radiofrequency ablation (RFA) in the liver can be negatively influenced by the surrounding blood flow. The indocyanine green (ICG) test can be used to evaluate the effective blood flow in the liver, and distance from the hilus can affect local blood flow. The aim of this study was to assess whether the ICG test or distance from the hilus could be used to predict the size of the ablated area in liver by RFA treatment of hepatocellular carcinoma (HCC) nodules. METHODS: The RFA measurements of 44 HCC nodules in 39 patients were retrospectively studied. Cases were included if they met the following criteria: (i) no catheter treatment before RFA; (ii) no movement of the RFA device; (iii) strict ablation time; and (iv) only one ablation. In all patients, ICG-R15 testing was done immediately before RFA and the initial therapeutic efficacy was evaluated by dynamic computed tomography scanning 2-5 days after RFA. The correlation between the maximum size of the RFA area and the ICG test results or the distance of the target area from the hilus (site of first portal vein divergence) were analyzed statistically. RESULTS: The ICG-R15 result was significantly correlated with the maximum diameter of the ablated area both in 2 cm-electrode tip length (R2 = 0.35, P = 0.0012), and in 3 cm-tip length (R2 = 0.26, P = 0.0377). Multiple-regression analysis showed that the electrode tip length (P = 0.0010) and ICG-R15 (P = 0.0046) were independent factors that could predict the maximum diameter of the RFA area. CONCLUSION: The results of ICG testing can be used to predict the size of the area that will be ablated at a target liver site before RFA treatment.

Aged↗
PubMed2006

Effects of tamsulosin on resting urethral pressure and arterial blood pressure in anaesthetized female dogs.

The purposes of the present study were to investigate the effects of the alpha1-adrenoceptor antagonists tamsulosin, prazosin and urapidil on resting urethral pressure in anaesthetized female dogs, and to compare the results with their effects on arterial blood pressure. Tamsulosin decreased resting maximal urethral pressure in the urethral pressure profile in a dose-dependent fashion, whereas it had almost no effect on mean arterial blood pressure. Prazosin and urapidil also dose-dependently decreased resting maximal urethral pressure, but these effects were accompanied by decreases in mean arterial blood pressure. Thus, of these three compounds, tamsulosin dose-dependently decreased resting maximal urethral pressure with negligible effect on mean arterial blood pressure in female dogs. These results suggest that tamsulosin will be useful in the treatment of voiding dysfunction associated with bladder outlet obstruction in women, with little hypotensive effect.

Adrenergic alpha-Antagonists↗
PubMed2006

The effect of periodontal surgery on bite force, occlusal contact area and bite pressure.

BACKGROUND: Tooth mobility resulting from the loss of periodontal support or trauma induced by periodontal surgery may change the amount of bite force (BF) and bite pressure (BP) and number of occlusal contact areas (OCAs). The aim of the authors' study was to compare BF, BP and OCA of teeth with periodontal disease before and after periodontal surgery with similar values of healthy teeth. METHODS: The authors performed quantitative analysis of BF, BP and OCA using a pressure measurement film. Ten patients with periodontitis who needed periodontal surgery served as the test group. The authors took measurements of BF, BP, OCA and mobility (using Miller's Mobility Index) just before surgery and at one, four and 12 weeks after surgery. They also measured clinical attachment levels (CAL) before surgery and 12 weeks after surgery. Ten subjects without periodontitis served as the control group. RESULTS: Although BF and OCA increased the first week after periodontal surgery, analysis of variance (ANOVA) showed no statistically significant differences at a 95 percent confidence interval. There were statistically significant differences between first-week mobility and that at four and 12 weeks (P = .001). A factorial ANOVA showed significant interaction between BF and mobility (P < .05). CONCLUSIONS: The authors' findings suggest that changes in BF, BP and OCA were not affected by periodontal surgery. However, mean mobility values and BF are correlated. Further investigations of this measurement method involving larger study populations and a longer follow-up period are needed. CLINICAL IMPLICATIONS: It seems to be helpful to follow occlusal changes after periodontal surgery using a pressure measurement film. It also may be suggested that this measurement method could be used to evaluate the treatment prognosis.

Adult↗
PubMed2006

The effect of periodontitis on biting abilities.

BACKGROUND: The aim of this study was to compare the biting abilities (bite force [BF] and occlusal contact area [OCA]) of chronic periodontitis patients with those of control patients with healthy periodontia by using pressure-sensitive sheets. METHODS: The study population consisted of 20 patients with chronic periodontitis whose initial periodontal therapy was completed and 20 control subjects with healthy periodontia. Periodontitis was diagnosed by radiographs and measurements of probing depth and clinical attachment level. Pressure-sensitive sheets were used for the quantitative analysis of BF and OCA. RESULTS: Both mean BF and OCA values were greater in the healthy control group compared to those of the study group. The differences between the groups were statistically significant at the 95% confidence level. CONCLUSION: Reduced periodontal support in the absence of inflammation negatively affected biting abilities.

Adult↗
PubMed2006

Effects of different sizes of beta-tricalcium phosphate particles on bone augmentation within a titanium cap in rabbit calvarium.

This study evaluated the effects of different sizes of beta-TCP particles on bone augmentation within a titanium cap. In 20 rabbits, the calvarium was exposed and a circular groove was prepared. After marrow penetration, a standardized hemispherical titanium cap was placed in the circular grove. The cap was filled with small-sized (100-250 microm) or medium-sized (250-500 microm) beta-TCP particles for the experimental site and without beta-TCP for the control site. After one and three months of healing, the animals were euthanized and examined histologically. There was a statistically significant difference in the amount of mineralized bone generated between the experimental and control groups in the three-month specimens. Furthermore, the medium-sized particles showed significantly more mineralized bone than did the small-sized particles. Based on these findings, we suggested that beta-TCP might be effective for bone formation and that medium-sized particles are more useful than small-sized particles in bone maturation.

Animals↗
PubMed2006

Treatment of Miller Class III recessions with enamel matrix derivative (Emdogain) in combination with subepithelial connective tissue grafting.

This report examines the clinical parameters and radiographic characteristics of two patients with Class III gingival recession who were treated with combined connective tissue grafting and root coverage with enamel matrix derivative. Both patients presented with multiple Class III recessions in the mandibular central incisors. Root coverage was achieved by connective tissue grafting in conjunction with the application of enamel matrix derivative. Soft tissue coverage of the root surfaces was achieved clinically, and radiographs showed improvement in the interproximal vertical bone defects.

Adult↗
PubMed2005

Development of a frequency-detuned interferometer as a prototype experiment for next-generation gravitational-wave detectors.

We report on our prototype experiment that uses a 4-m detuned resonant sideband extraction interferometer with suspended mirrors, which has almost the same configuration as the next-generation, gravitational-wave detectors. We have developed a new control scheme and have succeeded in the operation of such an interferometer with suspended mirrors for the first time ever as far as we know. We believe that this is the first such instrument that can see the radiation pressure signal enhancement, which can improve the sensitivity of next-generation gravitational-wave detectors.

Journal Article↗
PubMed2005

Effects of solifenacin succinate (YM905) on detrusor overactivity in conscious cerebral infarcted rats.

Solifenacin succinate [YM905, (+)-(1S,3'R)-quinuclidin-3'-yl 1-phenyl-1,2,3,4-tetrahydroisoquinoline-2-carboxylate monosuccinate] is a novel muscarinic receptor antagonist. We examined the effects of solifenacin and two other muscarinic receptor antagonists, tolterodine and propiverine, on detrusor overactivity in cerebral infarcted rats. Evaluation was done under conscious conditions using cystometry 1 day after middle cerebral artery occlusion. The cerebral infarcted rats showed decreases in bladder capacity and voided volume and an increase in residual volume, but no change in micturition pressure. Solifenacin increased bladder capacity and voided volume at doses of 0.03 mg/kg i.v. or more. Tolterodine increased bladder capacity and voided volume at 0.03 and 0.1 mg/kg i.v., while propiverine increased bladder capacity and voided volume at 1 mg/kg i.v. and at 0.3 and 1 mg/kg i.v., respectively. In contrast, none of the three drugs affected residual volume or micturition pressure. These results suggest that solifenacin may improve detrusor overactivity without causing urinary retention and may be a promising drug in the treatment of patients with overactive bladder syndrome.

Animals↗
PubMed2005

A study of arteriosclerosis in healthy subjects with HBV and HCV infection.

BACKGROUND: It is unclear whether infection with hepatitis B virus (HBV) or hepatitis C virus (HCV) affects arteriosclerosis. We performed a cross-sectional study to clarify the effect of HBV and HCV infection on arteriosclerosis. METHODS: The study subjects were 1806 healthy individuals who visited Shimane Environment and Health Public Corporation for routine medical check-ups. Serum levels of total cholesterol, high-density lipoprotein (HDL)-cholesterol, triglycerides, and blood glucose were investigated in all subjects. The degree of arteriosclerosis was assessed using systolic blood pressure, the bilateral ankle brachial index (ABI), the heart-carotid pulse wave velocity (HCPWV), and the heart-ankle PWV (HAPWV). These cardiovascular parameters were compared between control subjects and subjects with HBV and HCV infection, using analysis of covariance to adjust for confounding factors (sex, age, body mass index, and smoking and drinking). RESULTS: Of the 1806 subjects, 39 and 31 were diagnosed as positive for HBV and HCV infection, respectively. The remaining 1736 were considered to be the controls. Adjusted serum lipid levels in the subjects with HBV and those with HCV infection tended to be lower than those in the control subjects. Adjusted arteriosclerotic parameters in the subjects with HBV and HCV infection were similar to those in the control subjects, even after adjusting for serum lipid levels. CONCLUSIONS: Infection with HBV or HCV does not influence the severity of arteriosclerosis in healthy subjects.

Alcohol Drinking↗
PubMed2005

Muscarinic receptor binding, plasma concentration and inhibition of salivation after oral administration of a novel antimuscarinic agent, solifenacin succinate in mice.

1 A novel muscarinic receptor antagonist, solifenacin succinate, inhibited specific binding of [N-methyl-(3)H]-scopolamine ([(3)H]-NMS) in the mouse bladder, submaxillary gland and heart in a concentration-dependent manner. This inhibitory effect was greatest in the submaxillary gland, followed by the bladder and heart. 2 After oral administration of oxybutynin (76.1 micromol kg(-1)) or solifenacin (62.4, 208 micromol kg(-1)), a significant dose- and time-dependent increase in K(D) values for specific [(3)H]-NMS binding was seen in the bladder, prostate, submaxillary gland, heart, colon and lung, compared with control values. The increase in K(D) induced by oxybutynin in each tissue reached a maximum 0.5 h after oral administration and then rapidly declined, while that induced by solifenacin was greatest 2 h after administration and was maintained for at least 6 or 12 h, depending on the dose. The muscarinic receptor binding of oral solifenacin was slower in onset and of a longer duration than that of oxybutynin. 3 Plasma concentrations of oxybutynin and its active metabolite (N-desethyl-oxybutynin, DEOB) were maximum 0.5 h after its oral administration and then declined rapidly. Oral solifenacin persisted in the blood for longer than oxybutynin. 4 Pilocarpine-induced salivary secretion in mice was significantly reduced by oral administration of solifenacin and was completely abolished 0.5 h after oral oxybutynin. Although the suppression induced by solifenacin was more persistent than that due to oxybutynin, the antagonistic effect of solifenacin on the dose-response curves to pilocarpine was significantly weaker than that of oxybutynin. It is concluded that oral solifenacin persistently binds to muscarinic receptors in tissues expressing the M(3) subtype, such as the bladder.

Administration, Oral↗