Biomedical subjects

S Murai

Publications and source records attributed to S Murai.

At least 37 records · Page 2Linked to original sources

PubMed2000

Ru(II)- and Pt(II)-catalyzed cycloisomerization of omega-aryl-1-alkynes. Generation Of carbocationic species from alkynes and transition metal halides and its interception by an aromatic ring

The treatment of aryl-1-alkynes, such as 4-aryl-1-butyne, 5-aryl-1-pentyne, and 6-aryl-1-hexyne, with catalytic amounts of transition metal chlorides, such as PtCl(2) and [RuCl(2)(CO)(3)](2), at 80 degrees C in toluene results in cycloisomerization to give dihydronaphthalenes or dihydrobenzocycloheptenes, in which the cyclization mode is dependent on the length of the tethers. The reaction is limited to substrates containing terminal alkynes. A key step of the reaction is the intramolecular interception by an aromatic ring of the vinylmetal complex 2, which contains a cation center at the beta-position, generated from the electrophilic addition of transition metal halides toward an alkyne. The more electron-rich aryl systems are more reactive.

Journal Article↗

PubMed2000

Acylation of five-membered N-heteroaromatic compounds by ruthenium carbonyl-catalyzed direct carbonylation at a C-H bond

The ruthenium-catalyzed carbonylation at the C-H bond of five-membered N-heteroaromatic compounds is described. The reaction of imidazoles with CO and olefins in toluene in the presence of a catalytic amount of Ru(3)(CO)(12) results in carbonylation of the C-H bond at the 4-position (adjacent to the sp(2)-nitrogen) of the imidazole ring to give acylated imidazoles in good to high yields. A wide range of olefins can be utilized in the carbonylation reaction, and a variety of functional groups are compatible under the reaction conditions. Other five-membered N-heteroaromatic compounds, such as pyrazoles, oxazoles, and thiazoles, can also be used for the carbonylation reaction, and in all cases, carbonylation takes place exclusively at a C-H bond alpha to the sp(2) nitrogen. The reactivity of the five-membered heterocycles corresponds to the pK(a) of the conjugate acid of these heterocycles. The higher the pK(a) of the substrate, the higher is the reactivity. This indicates that the pK(a) values are related to the ability of the nitrogen atom in the substrates to coordinate to a ruthenium center. The coordination of the substrates to the ruthenium center in the catalyst complex is a necessary prerequisite for the carbonylation to proceed.

Journal Article↗

PubMed2000

Direct carbonylation at a C-H bond in the benzene ring of 2-phenyloxazolines catalyzed by Ru(3)(CO)(12). Scope, limitations, and mechanistic aspects

The ruthenium-catalyzed carbonylation at a C-H bond in the benzene ring of a 2-phenyloxazoline is described. The reaction of 2-phenyloxazolines with CO and ethylene in toluene in the presence of a catalytic amount of Ru(3)(CO)(12) resulted in propionylation at an ortho C-H bond in the benzene ring. The presence of the oxazoline ring on the benzene ring is essential for the carbonylation to proceed. Other heterocycles, such as oxazine, oxazole, and thiazoline rings, also served as acceptable directing groups as did the oxazoline ring. A wide functional group compatibility was observed. The site selectivity of the carbonylation was examined using meta-substituted phenyloxazolines. It was found that the carbonylation took place exclusively at the less-hindered C-H bond, irrespective of the nature of substituents, indicating that the site selectivity was determined by steric factors. The reaction was also applicable, not only to a benzene ring, but also to naphthyl and thiophenyl rings. Olefins such as propene and trimethylvinylsilane in place of ethylene could also be used in the carbonylation reaction, while other olefins, such as 1-hexene, tert-butylethylene, vinylcyclohexane, isoprene, 1,5-hexadiene, cyclohexene, 1, 5-cyclooctadiene, styrene, methyl acrylate, vinyl acetate, allyltrimethylsilane, and triethoxyvinylsilane did not afford the coupling products. An equilibrium between 2-phenyloxazolines, carbon monoxide, and olefins exists on one hand and the corresponding ketones on the other hand, and product composition is governed by the equilibrium thermodynamics of the system. The results of deuterium labeling experiments suggest that the catalysis involves a reversible C-H bond cleavage and that the rate-determining step is not the cleavage of a C-H bond. The results of kinetic study of the effects of CO pressure show that the reaction rate accelerates with decreasing CO pressure.

Journal Article↗

PubMed2000

Changes of liver fibrosis in chronic hepatitis C patients with no response to interferon-alpha therapy: including quantitative assessment by a morphometric method.

The aim of this study was to evaluate the antifibrotic effect of interferon (IFN)-alpha in chronic hepatitis C (CH-C) patients with no response to IFN-alpha therapy. We studied 76 patients (46 men, 30 women; mean age, 55.6 years) who received IFN-alpha intramuscularly, at a total close of 480 to 880MU for 6 months (group A). As a control group, we studied 50 patients (32 men and 18 women; mean age, 58.5 years) with CH-C who received medication other than IFN (ie, Strong-Neo-Minophagen C, ursodeoxycholic acid, and a herbal medicine, Sho-saiko-to [TJ-9]) and who had persistent alanine aminotransferase (ALT) elevation (group B). All patients were subdivided into three subgroups according to different patterns of ALT changes during the observation period, ie, (a) persistent ALT level < 60IU/ 1 (below about twice the upper limit of the normal range), (b) persistent ALT level > or = 60IU/1, (c) ALT levels other than (a) and (b). Liver biopsy was performed within 6 months prior to IFN therapy and more than 6 months after IFN therapy, while two liver biopsies were performed during therapy in group B. Liver fibrosis was compared between two specimens by staging. When the fibrosis stage was the same in the two specimens, we determined whether the fibrosis had improved or worsened by comparing the fibrotic ratio, ie, the ratio of the area of fibrosis to the area of the entire liver tissue specimen, calculated using computed graphic software. Serum aminoterminal peptide of type III procollagen (PIIIP) levels were measured on the day of the liver biopsy and their mean yearly changes were compared between the two groups. Improvement of liver fibrosis was found in 12% to 30% of patients in each ALT subgroup and in 24% of all patients in group A and there were no significant differences in liver fibrosis in comparison with findings in of group B when assessed by staging alone. However, these percentages rose to 59% to 75% and 66%, respectively, when liver fibrosis was assessed by the fibrotic ratio together with staging, resulting in a significant difference in fibrosis between groups A and B in total (P < 0.01). The mean yearly changes in serum PIIIP levels in each subgroup and in all patients in group A were below zero, indicating a tendency to improvement of fibrosis after IFN therapy, while these changes in group B were all above zero, except for subgroup (c). Improvement of fibrosis after IFN therapy was found in 15 of 24 patients (64%) whose ALT changes had the same pattern before and after IFN therapy, although no significant difference was noted between improved and worsened patients. These results suggest that IFN-alpha may have an antifibrotic effect even in CH-C patients with no overt response to IFN-alpha therapy, compared with the effect of medications other than IFN.

Alanine Transaminase↗

PubMed2000

In vivo changes in free choline level induced by autonomic agonists in mouse organs, including three major salivary glands.

Whether free choline levels are changeable in vivo in response to different types of autonomic agonists was examined in several mouse organs. Upon one subcutaneous injection of isoproterenol, phenylephrine and pilocarpine, choline levels in whole organ decreased, increased and decreased, respectively, in various organs within 30 min and returned to initial levels in a day. In the three major salivary glands, a delayed choline elevation also appeared on day 2 after one isoproterenol injection and subsided by day 6. Only in the three salivary glands more choline was accumulated after 10 once-a-day injections of isoproterenol than after one isoproterenol injection. Neither phenylephrine nor pilocarpine induced comparable choline accumulation in any organs examined. Isoproterenol injection repeated at a 2-day interval augmented the subsequent, delayed choline elevation. Examination with dobutamine and the adenylyl cyclase activator 6-(3-dimethylaminopropionyl)forskolin suggested that isoproterenol-induced immediate choline lowering was down-stream of cAMP synthesis and linked to cAMP more tightly than the choline accumulation, though both choline changes occurred via beta1-adrenergic receptors. Choline levels in the salivary glands also changed depending on the form of diet given and particularly in the parotid gland in parallel with gland weights. These results provide the first evidence for the autonomic control of intracellular choline levels; intracellular choline levels might be an integral part of the autonomic signalling pathway.

Adrenergic alpha-Agonists↗

PubMed2000

A comparison of the bactericidal effects and cytotoxic activity of three types of oxidizing water, prepared by electrolysis, as chemical dental plaque control agents.

Acid oxidizing water (AOW), neutral oxidizing water (NtOW) and acid oxidizing water with a low available chlorine concentration (AOW-LC) may be obtained by electrolyzing a solution of tap water containing various quantities of NaCl and HCl. This study compared the bactericidal effects of these waters on cariogenic and periodontopathogenic bacteria and their cytotoxicities against epithelial cells. AOW, NtOW and AOW-LC showed considerable bactericidal effects. The cytotoxicity of AOW-LC was significantly lower than the other solutions tested (P<0.0001). The results indicated that the three types of oxidizing water had similar activity in inhibiting bacterial plaque formation as conventional chemical plaque-control agents.

Aggressive Periodontitis↗

PubMed2000

Analysis of aspartate aminotransferase in gingival crevicular fluid assessed by using PocketWatch: a longitudinal study with initial therapy.

AIM: The aim of this longitudinal study was to analyze the level of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) by using PocketWatch before and after initial therapy in patients with chronic adult periodontitis and to determine the relationship between AST and conventional measures of periodontal status, such as probing depth, clinical attachment level, bleeding on probing, and gingival index. METHOD: A total of 11 patients with chronic adult periodontitis were enrolled. Their periodontal status and AST levels in GCF were measured at baseline and post-initial therapy (the number of pockets=67), and statistically analyzed. RESULTS: There was a statistically significant difference in AST levels between diseased periodontal sites (1.2+/-0.7) and healthy sites (0.3+/-0.6, p<0.05), and between baseline and post-initial therapy (p<0.05). Improvements in clinical status were noted following periodontal therapy and there was a corresponding decrease in AST levels. CONCLUSIONS: In conclusion, it is suggested that AST levels may be a useful adjunct in the clinical assessment of periodontal disease sites, since AST level decreases when periodontal status improves.

Adult↗

PubMed2000

Detection of mitochondrial DNA mutations in human gingival tissues.

The accumulation of mitochondrial DNA mutation is an important contributor to the aging process. Polymerase chain reaction (PCR) amplification was carried out on total DNA from gingival tissues of human subjects with ages of 19 to 64 years, and 5.0-kb and 7.4-kb deletions were found in the mitochondrial genomes of these subjects. This is the first report of mitochondrial DNA deletion detectable in human gingival tissues.

Adolescent↗

PubMed2000

Synthesis, circular dichroism, and absolute stereochemistry of a Fecht acid analog and related compounds

2,6-Dimethylspiro[3.3]heptane-2,6-dicarboxylic acid (2), an analog of the Fecht acid (1), was enantioresolved by the method of (1S,2R,4R)-(-)-2,10-camphorsultam yielding enantiopure acid (+)-2, the S absolute configuration of which was unambiguously determined by X-ray crystallography of camphorsultam amide derivative (R)-(-)-12b and chemical correlation. To determine the absolute configuration of chiral spiro[3.3]heptane compounds by the circular dichroism (CD) exciton chirality method, acid (+)-2 was converted to (+)-2,6-bis(phenylacetylenyl)-2,6-dimethylspiro[3.3]heptane (3) and (+)-2,6-bis(4-methoxyphenylacetylenyl)-2,6-dimethylspiro[3.3]heptane (4). The CD spectra of (+)-3 and (+)-4 exhibit intense exciton split Cotton effects of positive chirality, from which their S absolute configurations were confirmed.

Journal Article↗

PubMed2000

A preliminary comparative study of the guided tissue regeneration and free gingival graft procedures for adjacent facial root coverage.

OBJECTIVE: The purpose of this study was to compare the clinical efficacy of guided tissue regeneration with expanded polytetrafluoroethylene membranes to that of free gingival graft for treatment of adjacent facial gingival recession. METHOD AND MATERIALS: Eight adjacent gingival recession sites with Miller class I or II defects containing at least a maxillary or mandibular canine were selected in 6 patients. Four recession sites in 3 patients were treated with guided tissue regeneration, and the other 4 sites in the remaining 3 patients were treated with free gingival graft. Probing depth, gingival recession, attachment level, width of keratinized gingiva, and root coverage were recorded before surgery (baseline) and 6 months and 1 year postoperatively. RESULTS: Statistically significant improvements were found for gingival recession, attachment level, and root coverage from baseline to 6 months and 1 year postoperatively in both groups. Both procedures produced the same average reduction in gingival recession, gain in attachment level, and amount of root coverage after 1 year. Probing depths did not differ between groups throughout the study. The width of keratinized gingiva was significantly greater in the grafted group than in the guided tissue regeneration group. CONCLUSION: Both procedures produced the same average amount of root coverage, reduction in gingival recession, and gain in clinical attachment. The guided tissue regeneration procedure provided a better esthetic appearance without any difference in gingival color or architecture in cases of adjacent facial gingival recession.

Adult↗

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↗

PubMed1999

Improvement of multiple facial gingival recession by non-surgical and supportive periodontal therapy: a case report.

We report a case of multiple facial gingival recession which was improved by non-surgical and supportive periodontal therapy. The patient, a 28-year-old Japanese woman, presented for treatment of multiple facial gingival recession ranging from 1 to 4 mm on teeth 5 through 12 and 19 through 30. Periodontal plastic surgery to cover the exposed multiple root surfaces was suggested. However, because of emotional problems, the patient did not wish to undergo the procedures and instead accepted non-surgical periodontal therapy including oral hygiene instruction, scaling, and root planing. The exposed root sites were monitored at periodic maintenance visits, and gradual improvement through a coronal increase of the gingival margin was noted. The possible etiologic factors and healing process associated with this case are discussed.

Adult↗

PubMed1999

Relationship between levels of aspartate aminotransferase in gingival crevicular fluid and conventional measures of periodontal status assessed using PocketWatch: a cross-sectional study.

The aim of this cross-sectional study was to determine, using PocketWatch, the relationship between the level of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) and conventional measures of periodontal status, such as probing depth, attachment level, bleeding on probing and gingival index, in patients with untreated chronic periodontitis. A total of 15 patients with chronic periodontitis were enrolled. Their periodontal status and AST levels in their GCF were measured (n = 93) and statistically analyzed. There was a statistically significant difference in AST levels between diseased periodontal sites and healthy sites (p < 0.0001). The coefficients of correlation between AST levels and probing depth, attachment level and gingival index at all sites were 0.436, 0.266 and 0.468 (Spearman rank correlation). The correlation coefficients were too small to show a definite relationship between AST levels and individual measures of clinical periodontal status. However, AST levels may help to confirm clinical observations in patients with chronic periodontitis before therapy, since AST levels differentiate active and inactive periodontal diseased sites.

Adult↗

PubMed1999

Osseointegration around titanium screws placed into the areas between guided bone augmented sites compared with osseointegration around guided bone graft augmented sites in rabbit tibia.

The aim of this study was to compare the degree of osseointegration around titanium screws placed into the areas between guided bone augmented sites and guided bone graft augmented sites in 8 Japanese white rabbit tibia. The skin and periosteum were incised and lifted to expose the inner surfaces of both tibia. Eight rabbits were divided into 2 groups: 1) a guided bone augmentation (GBA) group of 2 rabbits, and 2) a guided bone graft augmentation (GBCA) group of 6 rabbits. In the GBA group, the bone marrow was penetrated several times in both tibial bones. Three titanium screws were inserted into the bone so that the top of each screw was 3 mm above the bone surface and covered with an expanded polytetrafluoroethylene membrane (ePTFE). In the GBGA group autogenous cortical bone (10 mm x 10 mm x 1 mm) was taken from the left tibia and grafted on the inner surface of the right tibial bone, titanium screws being similarly inserted. The surgical site was covered by ePTFE. After healing for 2 months, the animals were euthanatized, and the experimental area was prepared for histological investigation. New bone had formed on the surgical sites in the GBA group and grafted bone had survived in the GBGA group, with no sign of infection or membrane exposure. The degree of osseointegration around the screw was 67.6 +/- 11.2% (mean +/- SD) in the GBA group and 78.8 +/- 11.9% in the GBGA group. There was no significant difference between the groups (p = 0.29). The ratio of mineralized bone to bone marrow was 45.7 +/- 6.2% in the GBA group and 64.4 +/- 4.4% in the GBGA group. There was a significant difference between the groups (p < 0.05). Although there was no significant difference for osseointegration around the screw placed into the GBA and GBGA sites, the quality of newly generated bone or grafted bone was quite different. Therefore, we suggest that predictable bone augmentation beyond the bone surface can be achieved by either the GBA or the GBGA procedure with ePTFE. However, it was difficult to conclude which procedure was superior with respect to the osseointegration around the titanium screw.

Animals↗

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↗