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Biomedical subjects

Shuichi Sato

Publications and source records attributed to Shuichi Sato.

At least 37 records · Page 2Linked to original sources
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↗
PubMed2005

Changes in serum lipid concentrations in patients with chronic hepatitis C virus positive hepatitis responsive or non-responsive to interferon therapy.

BACKGROUND: Changes in serum lipid concentrations during the administration of interferon to patients with chronic hepatitis C virus (HCV) infection have not been fully investigated. The present study was designed to compare changes in serum lipid concentrations before, during and after interferon therapy in responders and non-responders to treatment. METHODS: In total, 101 patients with chronic HCV positive hepatitis were enrolled in this study. High dose interferon alpha was given on alternate days for 6 months. Six months after the end of treatment patients were assessed for the presence or absence of HCV RNA to determine the results of interferon treatment. The time courses of changes in serum lipid concentrations were measured in all patients. RESULTS: The total cholesterol level increased gradually during and after interferon therapy, and its pattern of change coincided with that of serum cholinesterase activity. Pretreatment serum cholesterol concentrations did not differ between responders and non-responders to interferon therapy. The serum triglyceride concentration, conversely, showed a sharp increase during interferon administration and returned to its basal level after the end of treatment. Responders to interferon therapy tended to have higher pretreatment triglyceride concentrations than did non-responders. CONCLUSIONS: We clarified that serum cholesterol and triglyceride levels showed different patterns of change during interferon therapy.

Adolescent↗
PubMed2005

Comparative study of nizatidine and famotidine for maintenance therapy of erosive esophagitis.

BACKGROUND: The therapeutic effect of combined administration of prokinetics and histamine H2 receptor antagonists (H2RA) in gastroesophageal reflux disease is reported to be superior to that of monotherapy with H2RA alone. In addition to its acid-suppressing effect, the H2RA nizatidine also has a prokinetic action by suppressing acetylcholine esterase. The present multicenter, randomized controlled study was performed to investigate whether nizatidine is superior to famotidine, which does not suppress acetylcholine esterase activity, in maintenance therapy for erosive esophagitis. In addition, the question as to whether the grade of erosive esophagitis affects the non-recurrence rate during the maintenance therapy with H2RA was also investigated. METHODS: Seventy-two patients with endoscopically healed erosive esophagitis after 8 weeks of initial treatment with proton pump inhibitors were randomly divided into two groups. Patients in the nizatidine group were treated with 150 mg nizatidine twice a day (b.i.d.), while patients in the famotidine group were treated with 20 mg famotidine b.i.d. for 6 months. At the end of therapy, and at the time when patients complained of symptoms, endoscopic investigations were repeated to find out whether the esophagitis had recurred. RESULTS: Nizatidine produced a significantly higher non-recurrence rate than famotidine (P = 0.049 in intention-to-treat [ITT] analysis). This difference of remission rate between nizatidine and famotidine was observed mainly in grade B esophagitis (P = 0.016 in ITT analysis). CONCLUSION: Nizatidine is a more effective H2RA than famotidine in the maintenance therapy of patients with reflux esophagitis.

Adult↗
PubMed2005

Three-dimensional evaluation for augmented bone using guided bone regeneration.

OBJECTIVE: This study evaluated new bone regeneration beyond the skeletal envelope within an occlusive titanium cap on rabbit calvaria using microfocus computed tomography images. METHODS: In 10 rabbits, the calvaria was exposed and a circular groove was prepared. After penetrating the marrow, a standard hemispherical titanium cap was placed in the groove and covered with a cutaneous flap. After 1 or 3 months, the animals were killed and the calvariae and titanium caps were dissected. After taking microfocus computed tomography images of the specimens, histological sections were made. The specimens were observed using three-dimensional images constructed from the microfocus computed tomography images, and the histological sections were examined to compute bone parameters. RESULTS: The three-dimensional images and histological specimens showed that new bone formed in flat, cup-like, and dome shapes. The bone parameters trabecular thickness and the proportion of marrow space to the capacity of the titanium cap increased, whereas bone density decreased, and there were significant differences between the 1- and 3-month groups. DISCUSSION: First, a cylinder of new bone formed from the existing bone. Gradually, bone formed along the cap wall and the new tissue formed in a crater indented centrally. Finally, the new tissue formed in the shape of a dome. CONCLUSION: Trabecular bone formed along the wall of the titanium cap, and bone filled the inside of the cap within 3 months.

Animals↗
PubMed2005

Effects of the enamel matrix derivative and beta-tricalcium phosphate on bone augmentation within a titanium cap in rabbit calvarium.

In vitro studies suggest that enamel matrix derivative (EMD) affects the early stages of osteogenic maturation by stimulating bone cell proliferation. In the present study, we evaluated the effects of EMD and beta-tricalcium phosphate (beta-TCP) on bone augmentation within a titanium cap in rabbit calvaria, using 14 adult male Japanese white rabbits. The calvarium was exposed, a circular groove prepared, the marrow penetrated, and a standard hemispherical titanium cap placed in the groove. The cap was filled with a mixture of beta-TCP and EMD at the experimental site, and was filled with beta-TCP alone at the control site. At 1 and 3 months after cap implantation, animals were euthanized, and histological sections prepared. The sections were stained with basic fuchsin and methylene blue, and were examined using light microscopy. At 1 month, EMD tended to increase the amount of bone, but there was no significant difference in the amount of new tissue and mineralized bone between the experimental and control sites. The present findings indicate that the present mixture of EMD and beta-TCP does not accelerate bone formation, compared with beta-TCP alone.

Animals↗
PubMed2004

Superiority of YM598 over atrasentan as a selective endothelin ETA receptor antagonist.

The binding affinities of (E)-N-[6-methoxy-5-(2-methoxyphenoxy)[2,2'-bipyrimidin]-4-yl]-2-phenylethenesulfonamide monopotassium salt (YM598) for native human endothelin ETA and ETB receptors expressed in human coronary artery smooth muscle cells (CASMC) and a human melanoma cell line, SK-Mel-28, respectively, were examined, and the results compared with those for the endothelin receptor antagonists atrasentan and bosentan. The in vivo endothelin ETA receptor inhibitory activities of YM598 and atrasentan were also compared through the suppression of the big endothelin-1-induced pressor response in pithed rats. Ki values of YM598, atrasentan, and bosentan for native human endothelin ETA receptors were 0.772, 0.0551, and 4.75 nM, while those for native human endothelin ETB receptors were 143, 4.80, and 40.9 nM, respectively. The calculated selectivity ratios of YM598, atrasentan, and bosentan for endothelin ETA versus ETB receptors were 185, 87 and 8.6, respectively. In pithed rats, YM598 and atrasentan inhibited the big endothelin-1 (1 nmol/kg)-induced pressor response in a dose-dependent manner on both intravenous and oral administration. The inhibitory effect of YM598 was less potent than that of atrasentan when these agents were intravenously administered, but closely similar on oral administration. These results suggest that YM598 has high selectivity for native human ETA against ETB receptors, and that YM598 is superior to atrasentan as an ETA receptor antagonist with regard to pharmacological bioavailability in rats.

Atrasentan↗
PubMed2004

Effects of tamsulosin on hypogastric nerve stimulation-induced intraurethral pressure elevation in male and female dogs under anesthesia.

The aim of the present study was to investigate the effects of tamsulosin, an alpha(1)-adrenoceptor antagonist, on hypogastric nerve stimulation-induced intraurethral pressure elevation in anesthetized male and female dogs and to evaluate sex differences in these effects. Additionally, the effects of tamsulosin were also compared with those of other alpha(1)-adrenoceptor antagonists, namely prazosin, naftopidil and urapidil. Tamsulosin dose-dependently inhibited hypogastric nerve stimulation-induced intraurethral pressure elevation, with doses required to induce 50% inhibition of the elevation (ED(50) values) of 0.72 and 0.74 microg/kg i.v. in anesthetized male and female dogs, respectively. Mean arterial blood pressure slightly decreased after administration of tamsulosin at a dose which inhibited intraurethral pressure elevation almost completely. Prazosin, naftopidil and urapidil also inhibited increases in intraurethral pressure in a dose-dependent fashion, but caused decreases in mean arterial blood pressure at the same doses. The estimated rank order of inhibitory potency for urethral response was tamsulosin>prazosin>naftopidil=urapidil. In conclusion, tamsulosin dose-dependently inhibited increases in intraurethral pressure with little effect on mean arterial blood pressure in both male and female dogs, and these effects were almost equipotent. These results indicate that tamsulosin will be useful in the treatment of dysuria associated with lower urinary tract symptoms in women as well as men.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed2004

In vitro and in vivo tissue selectivity profile of solifenacin succinate (YM905) for urinary bladder over salivary gland in rats.

Solifenacin succinate [YM905; (+)-(1S,3'R)-quinuclidin-3'-yl 1-phenyl-1,2,3,4-tetrahydroisoquinoline-2-carboxylate monosuccinate] is a new muscarinic receptor antagonist developed for the treatment of overactive bladder. The aim of the present study was to evaluate the in vitro and in vivo bladder selectivity profile of solifenacin over salivary gland in the same animal species, and to compare the results with those obtained for tolterodine, oxybutynin, darifenacin and atropine. Solifenacin and the other antimuscarinic drugs inhibited carbachol-induced increases in intracellular Ca(2+) levels in bladder smooth muscle cells and salivary gland cells isolated from rats in a concentration-dependent manner. The inhibitory effect of solifenacin for bladder smooth muscle cells (pK(i)=8.12) was 3.6-fold more potent than that for salivary gland cells (pK(i)=7.57). In contrast, the inhibitory effects of the other antimuscarinic drugs for bladder smooth muscle cells were 1.7- to 2.2-fold more potent than those for salivary gland cells. In anesthetized rats, solifenacin dose-dependently inhibited carbachol-induced intravesical pressure elevation and salivary secretion, and exhibited functional selectivity (3.7- to 6.5-fold) for urinary bladder over salivary gland. Tolterodine was also 2.2- to 2.4-fold more selective in inhibition of bladder response. In contrast, oxybutynin, darifenacin and atropine did not show functional selectivity for urinary bladder. These results indicate that solifenacin exerts greater selectivity for urinary bladder over salivary gland than tolterodine, oxybutynin, darifenacin and atropine, and may consequently provide symptomatic benefit in the treatment of overactive bladder with less dry mouth than currently used antimuscarinic drugs.

Animals↗
PubMed2004

Effects of selective endothelin ET(A) receptor antagonists on endothelin-1-induced potentiation of cancer pain.

In some diseases in which endothelin-1 production increases, e.g. prostate cancer, endothelin-1 is considered to be involved in the generation of pain. In the present study, we 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 the nociception potentiated by endothelin-1 in a cancer inoculation-induced pain model in mice, induced by inoculation of the androgen-independent human prostate cancer cell line PPC-1 into the hind paws of severe combined immunodeficiency (SCID) mice. No pain responses were observed in the sham-operated mice, whereas monophasic pain responses were observed in the PPC-1-inoculated mice. Endothelin-1 (1 to 10 pmol/paw) but not sarafotoxin S6c potentiated the pain response in prostate cancer-inoculated mice. Both YM598 and atrasentan (0.3 to 3 mg/kg, p.o.) significantly inhibited the endothelin-1 (10 pmol/paw)-induced potentiation of nociception in a dose-dependent manner. These results suggest that selective endothelin ET(A) receptor antagonists might relieve pain in patients with various diseases in which endothelin-1 production is increased, e.g. prostate cancer.

Analgesics, Non-Narcotic↗
PubMed2004

Pharmacological characterization of YM598, a selective endothelin-A receptor antagonist.

The binding affinities of YM598, a novel endothelin-A (ETA) receptor antagonist, for native human ETA receptors expressed in human coronary artery smooth muscle cells and endothelin-B (ETB) subtypes in the human melanoma cell line SKMel- 28 were compared with those of atrasentan and bosentan. The in vivo ETA receptor antagonist activities of YM598 and atrasentan were also evaluated in pithed rats. The inhibitory dissociation constant values of YM598, atrasentan and bosentan were 0.772, 0.0551 and 4.75 nM, respectively, for native human ETA receptors, and 143, 4.80 and 40.9 nM, respectively, for native human ETB subtypes. The calculated selectivity ratios of YM598, atrasentan and bosentan for ETA versus ETB receptors were 222, 136 and 13.0, respectively. In pithed rats, YM598 and atrasentan inhibited the big endothelin-1 (1 nmol/kg)-induced pressor response in a dose-dependent manner, after both intravenous and oral administration. The inhibitory effect of YM598 was less potent than that of atrasentan when these agents were intravenously administered, but those of both agents were comparable when orally administered. These results suggest that YM598 has a high selectivity for native human ETA receptors against ETB receptors, and that YM598 is superior to atrasentan as an ETA receptor antagonist, with regard to pharmacological bioavailability in rats.

Administration, Oral↗
PubMed2004

Inhibitory effects of a selective endothelin-A receptor antagonist YM598 on endothelin-1-induced potentiation of nociception in formalin-induced and prostate cancer-induced pain models in mice.

In some diseases in which endothelin-1 (ET-1) production increases (e.g. prostate cancer), ET-1 is considered to be involved in the generation of pain. In the present study, we investigated the effects of a selective endothelin-A receptor antagonist, YM598, on the nociception potentiated by ET-1 in formalin-induced and cancer inoculation-induced pain models in mice. The formalin-induced pain model was prepared by intraplantar injection of 0.7% formalin into the hind paws of ICR mice, and the cancer pain model was prepared by inoculation of the human prostate cancer cell line PPC-1 into the hind paws of severe combined immunodeficiency mice. Formalin caused a biphasic pain response and paw edema in the mouse hind paw. ET-1 (10 pmol/paw) potentiated these responses, and single oral administration of YM598 (0.3-3 mg/kg) significantly inhibited this ET-1-induced potentiation of nociception and paw edema. ET-1 (10 pmol/paw) also potentiated the pain response in prostate cancer-inoculated mice. Both YM598 and atrasentan (0.3-3 mg/kg) significantly inhibited the ET-1-induced potentiation of nociception. These results suggest that selective endothelin-A receptor antagonists relieve pain in patients with various diseases in which ET-1 production increases (e.g. prostate cancer).

Administration, Oral↗
PubMed2004

Effects of a new ultrasonic scaler on fibroblast attachment to root surfaces: a scanning electron microscopy analysis.

OBJECTIVE: A study was conducted to examine the effectiveness of scaling and root planing using a new ultrasonic scaler (Vector). METHODS: Eighty extracted teeth affected by periodontal disease were sorted into four groups of 20, each of which was subjected to one the following procedures: use of the Vector, Vector with polish, Enac and a Gracey scaler. The time spent on cleaning was measured. Half of the sample teeth were examined at random for surface roughness, and the surface texture was evaluated by means of the Remaining Calculus Index (RCI) and the Roughness and Loss of Tooth Substance Index (RLTSI). The remaining samples were incubated in dishes with a suspension of fibroblasts. After measuring the number of attached cells, the attachment of fibroblasts was observed by scanning electron microscopy. RESULTS: The RLTSI values in the Vector and Vector with polish groups were significantly lower than those in the Enac and Gracey groups, whereas the number of attached cells in the Vector with polish group was larger than in the Enac group. Cell attachment in the Vector and Vector with polish groups proved to be better than in the Enac and Gracey groups. CONCLUSION: Since use of the Vector with polish was able to provide scaling and root planing with minimal damage and tight attachment of fibroblasts, it is suggested that this may be a useful instrument for scaling and root planing.

Cell Adhesion↗
PubMed2004

Spontaneous correction of pathologic tooth migration and reduced infrabony pockets following nonsurgical periodontal therapy: a case report.

This case report describes the spontaneous correction of pathologic tooth migration and reduced infrabony pockets after nonsurgical periodontal therapy. A 3-mm diastema between the maxillary incisors was closed completely, and the mandibular teeth, which had migrated pathologically, returned to the optimal position. Clinical evaluation showed a significant reduction in probing depth, with increased clinical attachment and bone deposition demonstrated radiologically.

Alveolar Bone Loss↗