Biomedical subjects

S Murai

Publications and source records attributed to S Murai.

At least 19 recordsLinked to original sources

PubMed1999

Cyclosporin A inhibits H2O2-induced apoptosis of human fibroblasts.

Several clinical studies have shown that cyclosporin A (CsA) is effective for treating a variety of chronic inflammatory and autoimmune diseases. Because reactive oxygen species are believed to play a key role in the development of these diseases, causing cell apoptosis, we investigated whether CsA inhibits H2O2-induced apoptosis. Preincubation of human fibroblasts with CsA dose-dependently decreased H2O2-induced apoptosis. Apoptosis suppression by CsA was correlated with the prevention of mitochondrial dysfunction and caspase activation. Thus, our results suggest that the inhibition of apoptosis by CsA may at least partly contribute to the anti-inflammatory effect of CsA.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1998

Nicotine inhibits the production of inflammatory mediators in U937 cells through modulation of nuclear factor-kappaB activation.

Cigarette smoke is a major risk factor for lung cancer and respiratory infections. This increased susceptibility may result from cigarette smoke-induced impairment of the immune system. In this study, we evaluated the effect of nicotine on the production of inflammatory mediators by activated macrophages. Pretreatment with nicotine caused a significant inhibition of LPS-induced IL-1, IL-8, and PGE2 expression at the transcriptional level in U937 cells. Nicotine inhibited the activation of a transcription factor, NF-kappaB, which in turn, binds to and mediates transcriptional activation of these genes. These inhibitory effects of nicotine may contribute to cigarette smoke-induced immunosuppression.

Cyclooxygenase 2↗

PubMed1998

Sex-dependent differences in the concentrations of the principal neurotransmitters, noradrenaline and acetylcholine, in the three major salivary glands of mice.

The concentrations of principal neurotransmitters in the submandibular, parotid and sublingual glands were compared between two pairs of age-matched male and female ddY mice, one pair consisting of 4-week-old and the other 8-week-old animals. Sex-dependent differences in both noradrenaline and acetylcholine concentrations were observed only in the submandibular gland, although each neurotransmitter showed distinct features. The acetylcholine concentration in the submandibular gland was higher in the female at both ages, whereas the noradrenaline concentration was higher in the female at the age of 4 weeks but became higher in the male by the age of 8 weeks. On the other hand, the total amounts of noradrenaline and acetylcholine per submandibular gland were already greater in the male at 4 weeks, and the male parotid and sublingual glands also had a greater noradrenaline content by 4 weeks and 8 weeks, respectively. Each type of gland had similar growth rates over the 4-week period, and the male submandibular and parotid glands were heavier than the female. In addition, each type of gland had its characteristic ratio of noradrenaline to acetylcholine concentration, which did not differ between the sexes and remained in similar basic patterns during the period examined, except for the submandibular gland of 8-week-old male mice, which developed greater amounts of the sympathetic neurotransmitter noradrenaline.

Acetylcholine↗

PubMed1998

Cyclosporin A inhibits collagenase gene expression via AP-1 and JNK suppression in human gingival fibroblasts.

A frequent side effect of cyclosporin A (CsA) administration is gingival overgrowth. Although the molecular mechanisms of CsA-induced gingival overgrowth are still unknown, it has been postulated that CsA acts on lipopolysaccharide (LPS) to induce fibroblastic activity, which results in an increase of the extracellular matrix. Here we provide evidence that CsA is able to affect signal transduction of LPS-induced collagenase expression in fibroblasts. Treatment of fibroblasts with LPS caused activation of collagenase gene, activator protein-1 (AP-1) and c-Jun N-terminal kinase (JNK). These activations were blocked by CsA. We suggest that inhibitory effects of CsA on LPS-induced signal transduction may contribute to the mechanism of CsA-induced gingival overgrowth.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1998

Effects of repeated hand instrumentation on the marginal portion of a cast gold crown.

A study was conducted to evaluate the effects of repeated hand instrumentation on the marginal portion of a cast gold crown. Seven extracted periodontally diseased premolars were used. The finishing line of the preparation was placed on the root surface and then the crown was cast and cemented in the usual manner. One proximal surface of each sample was divided into 2 areas: root planing (RP) area and RP plus polishing (RPP) area. The marginal portion of the crown was measured to give a baseline value using a surface roughness- and profile-analyzing system. Then, the marginal portion was painted with a waterproof pen. RP was performed to remove paint in the RP area with the curets. In the RPP area, RP followed by polishing was done by silicone polishing points and a rubber cup with polishing paste. The relevant procedures and measurements were repeated 3 times in each area. Changes in the sample roughness and profile were evaluated and compared between the 2 techniques. The results showed that repeated instrumentation altered the surface of the marginal portion of the cast gold crown, resulting in increased roughness in both areas (P < 0.01). However, the roughness of the RPP area was considerably restored to the baseline value by polishing after RP. Therefore, it is suggested that polishing after RP smoothes the marginal portion of the cast gold crowns and appears to be an efficient prophylactic system.

Bicuspid↗

PubMed1998

Effects of bioabsorbable and non-resorbable barrier membranes on bone augmentation in rabbit calvaria.

The aim of this study was to compare the effects of bioabsorbable and non-resorbable membranes on experimental guided bone augmentation in 8 Japanese white rabbits. A cutaneous flap was demarcated and raised from the forehead of each animal, the periosteum was lifted, and the calvarial bone on both sides of the midline was exposed. A titanium screw was inserted into the bone on each side of the midline and one screw was covered with a bioabsorbable (polylactic acid) membrane and the other with a non-resorbable (expanded polytetrafluoroethylene) membrane. The implanted screws and membranes were then covered with the periosteum and cutaneous flap. After healing for 6 months, the animals were euthanized and the experimental area was prepared for histological investigation. New bone had formed under both membranes with no sign of infection or membrane exposure. The amount of newly generated bone (89.0 +/- 17.3% versus 54.7 +/- 14.0%, P <0.05) and the percentage of newly generated bone height (81.5 +/- 6.3% versus 58.9 +/- 7.8%, P <0.05) in the space beneath the non-resorbable membrane was greater than that beneath the bioabsorbable membrane. However, there were no statistically significant differences between the bioabsorbable and non-resorbable membranes with respect to the percentage areas of mineralized bone (52.3 +/- 11.3% versus 47.1 +/- 6.7%, P = 0.8658) and bone marrow (47.7 +/- 11.3% versus 52.9 +/- 6.7%, P = 0.4838) and bone contact with the screw (88.3 +/- 6.9% versus 89.2 +/- 7.3%, P = 0.9999). In conclusion, at least within the limitations of this rabbit model, we suggest that non-resorbable membranes with sufficient stiffness should be used to obtain greater bone volume and height instead of bioabsorbable membranes for the GBR procedure, and that this will facilitate predictable bone augmentation in spaces beyond the bone surface. Therefore, the bioabsorbable membrane could not replace the non-resorbable membrane used in this model.

Absorbable Implants↗

PubMed1998

The inhibitory effect of funoran and eucalyptus extract-containing chewing gum on plaque formation.

The purpose of this study was to evaluate the inhibitory effect of funoran containing chewing gum (FG) and eucalyptus extract- containing chewing gum (EG) on plaque formation. Fifteen dentists or dental students were assigned a random order of use of either FG, EG or a control gum. All subjects received professional tooth cleanings before the experiment. During the four-day test periods, no oral hygiene measures were allowed other than chewing three pieces of gum for approximately 10 min daily. Chewing gum was used following each morning, noon and evening meal. Plaque formation was evaluated by the Quigley and Hein index. The FG (1.83 +/- 1.1) and EG (1.97 +/- 1.1) significantly reduced plaque compared to the control gum (2.57 +/- 1.2). Our results suggest that FG and EG may be useful in inhibiting dental plaque formation.

Adult↗

PubMed1998

Effects of experimental osteoporosis on alveolar bone loss in rats.

A study was conducted to investigate the relationship between osteoporosis and alveolar bone loss. Alveolar bone loss was evaluated by radiographic and visual inspection of rats with experimental osteoporosis. Twenty 4-week-old female Sprague-Dawley rats were divided into the following groups: Group A-ovariectomized and given a standard solid diet; Group B-ovariectomized and given a calcium-deficient diet; Group C-sham-ovariectomized and given a standard solid diet; and Group D-sham-ovariectomized and given a calcium-deficient diet. After 4 weeks, the rat were euthanatized. The maxillae, mandibles, femurs, and tibias were removed carefully and fixed in 10% neutral buffered formalin. The bone mineral density of each bone and the alveolar bone loss were measured. The bone mineral densities of the maxillae, mandibles, femurs and tibias in Group C were significantly higher than those in Groups B and D, but not higher than those in Group A. However, there were no significant differences between any of the groups with regard to alveolar bone loss from the cemento-enamel junction to the molar bone crest. Therefore, it was concluded that osteoporosis itself may not be capable of causing periodontal destruction, and thus may not be a major factor in periodontal disease.

Alveolar Bone Loss↗

PubMed1998

Comparison of osseointegration between hydroxyapatite-coated and uncoated threaded titanium dental implants placed into surgically-created bone defect in rabbit tibia.

The purpose of this study was to compare the degree of osseointegration between hydroxyapatite (HA)-coated and uncoated threaded titanium dental implants placed into a surgically created bone defect with or without an expanded polytetrafluorethylene (ePTFE) membrane. A conventional implant site was prepared and either a HA-coated or an uncoated implant was placed in each tibia of 12 rabbits (conventional group). A bone defect approximately 3 mm in width was created on the distal end of the conventional site and either a HA-coated or an uncoated implant was placed there (bone defect group). For another group, the same procedure was performed as in the bone defect group, except the implant sites were covered with ePTFE membranes (ePTFE group). After 4 months, the rabbits were sacrificed. Specimens were prepared and examined histometrically. The results demonstrated that HA-coated threaded titanium dental implants consistently showed a greater amount of osseointegrated surface either in the conventional site or defect region with and without ePTFE membranes in this animal model. In conclusion, a HA-coated threaded titanium implant may be the choice of dental implants to establish greater osseointegration with the defect or conventional site.

Animals↗

PubMed1998

Incomplete fractures in intact bilateral maxillary first molars: a case report.

A case of incomplete fractures occurring bilaterally in intact maxillary first molars is described. The etiology, diagnosis, and treatment of incomplete tooth fractures are discussed. The clinical results in this case showed that early diagnosis and treatment can prevent further extension of the crack into the pulp and subsequent complete tooth fracture.

Bruxism↗

PubMed1998

[Diagnosis and treatment of pulmonary tuberculosis complicated with chronic liver disease].

Immunocompromised or malnutritional hosts are high risk group of pulmonary tuberculosis. Chronic liver disease especially decompensated cirrhosis of the liver is one of the risk group for this infection. When ascites or pleural effusion developed in patient with hepatic cirrhosis, complication of pulmonary tuberculosis must be considered. In such condition, drug metabolism was impaired so that anti-tuberculous drugs should be used carefully, but in almost cases except decompensated cirrhotic patients are tolerable for standard anti-tuberculous combination therapy and they could be cured. Hepatitis C virus infection is common in patients with old pulmonary tuberculosis because many of them were infected Hepatitis C virus at the time of blood transfusion for pulmonary resection or thoracoplasty. In such condition recurrence of pulmonary tuberculosis is rare but probability of recurrence must be considered when they developed decompensated cirrhosis.

Chronic Disease↗

PubMed1997

Adsorption and Recovery of Ionic Surfactants by beta-Cyclodextrin Polymer

The adsorption and recovery of ionic surfactants, such as dodecylbenzenesulfonic acid (DBS) and benzalkonium chloride (BKC), from an aqueous solution were studied using the beta-cyclodextrin polymer (beta-CDP). BKC always demonstrated a higher adsorption efficiency than DBS in batch tests, isotherms, and column tests. The adsorption characteristics of the surfactants seemed to be caused by inclusion into beta-CD, and they were easily determined using the Langmuir adsorption isotherm. Furthermore, the surfactants adsorbed by beta-CDP were easily released by shaking it with a mixture of water and methanol. Recovery efficiency was dependent on the mixture ratio of the solvent, and regenerated beta-CDP was reusable as an adsorbent.

Journal Article↗

PubMed1997

Changes in the noradrenaline and acetylcholine content of three major salivary glands and in the salivation and protein component patterns of whole saliva in chronically isoprenaline-administered mice.

One group of mice was injected subcutaneously with 20 mg/kg body wt isoprenaline each day for 10 days; another group (control) was injected with saline. Half the animals of each group were kept untreated for a further 10 days for restoration. Chronic administration of isoprenaline caused enlargement of parotid (4-fold) and submandibular glands (1.7-fold) but had no effect on sublingual glands. Concomitantly, noradrenaline and acetylcholine contents were, in parallel, increased in parotid, decreased in sublingual, and unchanged in submandibular glands. Under these conditions, pilocarpine- or isoprenaline-induced salivation was not affected but phenylephrine-induced salivation was augmented; the protein component patterns of saliva characteristic of the three sialogogues were also changed. In addition, secretory proteins whose synthesis was induced by isoprenaline were found to be secreted by stimulation with different types of sialogogues. Most changes were reversible. These results indicate that continued beta-adrenoceptor stimulation not only causes broadly altered forms of saliva, probably by involving, in part, alpha-adrenoceptor hypersensitivity, but also changes the activities of both sympathetic and parasympathetic nerves to salivary glands in parallel, though the extent differs among the three glands.

Acetylcholine↗

PubMed1997

Audiologic features of hearing loss due to the 1,555 mutation of mitochondrial DNA.

We proved a 1,555 mutation of mitochondrial DNA in one member of each of three families with familial streptomycin hearing loss, and report the pedigrees and audiologic features. DNA was extracted by the standard method. The 1,555 A to G mutation was identified in all three patients and confirmed by direct sequencing of the polymerase chain reaction products by a cycle sequencing method. On audiograms, the hearing loss was sensorineural, bilateral, and symmetric, showing a high-tone loss or a profound loss particularly in the high-tone range, and the "symmetry law" of Langenbeck was applicable. The superimposed audiograms of members of one family did not cross themselves, proving the applicability of the "never-cross principle of audiograms."

Adult↗

PubMed1997

Arg-Gly-Asp(RGD) peptides inhibit Streptococcus mitis to adhere to fibronectin.

Fibronectin (Fn) is a multifunctional adhesive protein found on cell surfaces as well as in plasma. It is also believed to play an important role in bacterial adherence to host tissues. Molecular analyses of Fn have shown that the amino acid triplet arginine-glycine-aspartic acid (RGD) sequence functions as a binding site. We examined the role of the RGD sequence on bacterial adherence to Fn. The pretreatment of Streptococcus mitis with synthetic RGD-containing peptide reduced the number of bound bacteria to the Fn coated plates by 76%. In contrast, a control peptide containing the RGE sequence showed no inhibition. These data indicate that synthetic RGD peptides may be useful for the inhibition of bacterial adherence to Fn on host cell surfaces.

Amino Acid Sequence↗

PubMed1996

Effects of short-term (2 weeks) streptozotocin-induced diabetes on acetylcholine and noradrenaline in the salivary glands and secretory responses to cholinergic and adrenergic sialogogues in mice.

Acetylcholine and noradrenaline concentrations in the submandibular, parotid and sublingual glands, and pilocarpine-, isoproterenol- and phenylephrine-induced salivation, were estimated in streptozotocin (STZ)-induced diabetic mice. Diabetic mice showed significant increases in acetylcholine and noradrenaline (expressed as nmol/gland) in sublingual and submandibular glands, respectively. The total volume of crude whole saliva in diabetic mice in response to pilocarpine and isoproterenol but not to phenylephrine was significantly reduced. These results suggest that alterations in the neurotransmitter levels and secretory function in the salivary glands occur rapidly after the induction of STZ diabetes, and that the secretory function appears to be more susceptible to effects of diabetes in the early stages than the autonomic nervous system. Since the alterations in neurotransmitter concentrations in diabetic salivary glands were slight and partial, it seems that they are unrelated to the markedly reduced salivation in response to pilocarpine and isoproterenol observed in these short-term diabetic mice.

Acetylcholine↗

PubMed1996

Structure of heads A and B of myosin studied by tryptic digestion of myosin subfragment-1.

We studied the difference in the structure of head B (P1-burst head) and head A of myosin by limited tryptic digestion of myosin subfragment-1 (S-1), and using antibodies (anti-A and anti-B) which bind specifically with each head. The antibodies were prepared using peptides with sequences identical to those around the reactive lysine residue of heads A and B. When myosin subfragment-1 (S-1) was cleaved limitedly by trypsin, S-1 heavy chain (100 kDa) was digested into fragments of 25, 50, and 20 kDa. Two fragments with molecular masses of 75 and 27 kDa were transiently produced in the initial phase of digestion. Anti-A and anti-B antibodies bound only with peptides that contained the reactive lysine residue [S-1 heavy chain (100 kDa), 75-, 27-, and 25-kDa peptides], thus showing specific binding with antigen peptide. However, the 27-kDa fragment bound more strongly with anti-B antibody than with anti-A antibody. When S-1 was separated into fractions rich in S-1A and S-1B using insoluble anti-A or anti-B antibody, each antibody bound more strongly with the S-1 heavy chain (100 kDa) of its corresponding fraction by Western immunoblotting. These results suggest that the antibodies react specifically with peptides even after SDS-PAGE and membrane-blotting, and that the structure of the 25 kDa 50 kDa junction differs between heads A and B of myosin.

Animals↗

PubMed1996

Inhibitory effects of acid water prepared by an electrolysis apparatus on early plaque formation on specimens of dentine.

The aim of this study was to compare the effects of acid water prepared by an electrolysis apparatus with placebo treatment on the ultrastructure of early plaque formed on dentine specimens attached to retainers in the oral cavity. Dentine specimens were taken from 12 healthy extracted human 3rd molars. 4 dentine specimens were placed in the both the right and left buccal flanges of retainers fabricated from self-setting acrylic resin. The retainers were placed on both maxillary buccal sites in 6 subjects. The test solution was acid water (AW) prepared by an electrolysis apparatus with a pH of 2.7 and an oxidation-reduction potential of more than 1100 mV. As a positive control, 0.2% chlorhexidine digluconate (CHX) solution was used and normal saline solution as a negative control. 4 specimens placed in the right and left retainers were randomly allocated to 4 treatments as follows: treatment A, washing with AW; treatment B, washing with CHX solution; treatment C, washing with normal saline; treatment D, no washing. Washing was carried out in a plastic beaker containing 30 ml of each solution for 30s 2X daily over a 7-day period. The specimens were then carefully removed from the retainers, the morphology and thickness of the plaque formed examined by SEM, and the developmental condition of the plaque analyzed statistically. The plaque on the specimens in treatments A and B consisted mainly of coccoid forms. Mature plaque formation with complex flora was seen on the specimens in treatments C and D. The mean thickness of the plaque deposits on the dentin specimens as measured on SEM photographs magnified 2000 times was 8.80 mm for treatment. A, while in treatment B it was 3.90 mm. Plaque thickness for treatment C was 24.97 mm, and for treatment D 25.67 mm. The thickness of plaque formed on the sectioned specimens was significantly less for treatments A and B than for treatments C and D. However, there was no statistically significant difference between treatments A and B, and between treatments C and D (p < 0.0001). The results of this short-term study indicate that AW washing has almost the same potential for inhibition of plaque formation as CHX washing, and is more effective for inhibiting plaque formation than washing with sterile saline. It is therefore concluded that AW may be useful as an anti-plaque agent.

Acids↗