Biomedical subjects

R Sato

Publications and source records attributed to R Sato.

At least 37 records · Page 2Linked to original sources

PubMed2002

Distribution pattern of versican, link protein and hyaluronic acid in the rat periodontal ligament during experimental tooth movement.

The ability of the periodontal ligament (PDL) to rapidly remodel is the basis of orthodontic tooth movement. During the tooth movement, matrix proteoglycans (PGs) may play important roles in spatial, mechanical and biological aspects for the maintenance and repair of the PDL. The aim of this study was to characterize the distribution of a large hyaluronic acid (HA)-binding proteoglycan, versican, link protein (LP) and HA in the rat molar PDL during experimental tooth movement by histochemical and immunohistochemical methods. Experimental tooth movement was performed according to Waldo's method. Histologically, regressive changes, such as decrease of fibroblasts and collagen fibers and exudative change of edema were observed in the compressive side and progressive changes, such as proliferation of fibroblasts and collagen fibers, in the strain side one day after treatment. By 3 days after tooth movement, regressive or progressive changes were not observed in either side. Using monoclonal antibodies specific to versican core protein or LP, the positive immunoreactivity for both molecules was constantly observed throughout the PDL. After the experimental force was applied to the tooth, however, the immunostainings of versican and LP became significantly intense only in the compressive side but decreased in the strain side. The intensity in the compressive side was strongest one day after the force was applied and gradually diminished thereafter. HA of both sides did not change during experimental tooth movement. Since HA is present in the PDL, large amounts of versican and LP expressed in the compressive side may create large hydrated aggregates via their association with HA that dissipates the compressive force applied to this tissue.

Animals↗

PubMed2002

Association of polymorphisms of the renin-angiotensin system and bradykinin B2 receptor with ACE-inhibitor-related cough.

The use of angiotensin-converting enzyme (ACE) inhibitors to treat hypertension has recently increased. However, their use is associated with a persistent dry cough in a significant percentage of such patients. The present study was designed to assess the contribution of polymorphisms as a genetic marker of ACE-inhibitor-related cough in a Japanese hypertensive population. Genotyping was carried out in 190 patients, 70 with cough and 120 without cough, who had been treated with ACE inhibitors. Polymorphisms of ACE insertion/deletion (I/D), angiotensin II type 1 receptor (1166A/C), type 2 receptor (3123C/A), and bradykinin B2 receptor (-58T/C, exon 1, I/D), were analyzed in these subjects. The TT genotype and T allele of bradykinin B2 receptor (-58T/C) were identified at a significantly higher frequency in the cough (+) patients than in the cough (-) patients. This difference was even more pronounced in women. However, there was no significant relationship between polymorphisms of ACE, angiotensin II receptors, or bradykinin B2 receptor exon 1, and occurrence of ACE-inhibitor-related cough. The transcriptional activity of the bradykinin B2 receptor promoter is involved in the occurrence of cough, and this new marker may provide a valuable tool to detect patients at risk of developing this side effect of ACE inhibitors. In conclusion, Susceptibility to develop cough is associated with a genetic variant of the bradykinin B2 receptor promoter; thus, it may be possible to identify those patients who will develop this adverse reaction to ACE inhibitors in advance.

Adult↗

PubMed2002

Sensitivity of biopsy site in evaluating regression of gastric atrophy after Helicobacter pylori eradication treatment.

BACKGROUND: Helicobacter pylori infection is a major cause of the progress of gastric glandular atrophy, a high-risk background factor in the development of gastric cancer. Regression of gastric atrophy is critical to prevention of cancer by H. pylori eradication treatment. However, it is controversial whether gastric atrophy regresses after H. pylori eradication. AIM: To determine the most sensitive and appropriate biopsy site for evaluation of regression of atrophy after treatment. SUBJECTS AND METHODS: Thirty-eight patients who showed regression of gastric atrophy in histology after treatment were investigated. Four biopsy specimens from the lesser and greater curvatures in the antrum and corpus were evaluated before and after treatment according to the Updated Sydney System. RESULTS: Regression of atrophy after treatment was seen in 30 of 38 biopsy specimens from the lesser curvature of the corpus (79%), and this site was most sensitive. Odds ratio of this site to the others was 8.28. Regression of atrophy in this site was observed at 12.2 months in the younger patients and 15.9 months in the elder patients. CONCLUSION: Biopsy sampling from the lesser curvature of the corpus is the most sensitive and appropriate for evaluation of regression of gastric atrophy after H. pylori eradication treatment.

Adult↗

PubMed2002

Eradication rates of clarithromycin-resistant Helicobacter pylori using either rabeprazole or lansoprazole plus amoxicillin and clarithromycin.

BACKGROUND: The resistance of Helicobacter pylori to clarithromycin has become one of the primary reasons for eradication failure. AIM: To compare the eradication rates of triple therapy using amoxicillin (A), clarithromycin (C) and rabeprazole (R) or lansoprazole (L) against clarithromycin-sensitive and clarithromycin-resistant strains. METHODS: Two hundred and ninety-five patients were randomly divided into four groups and treated for 1 week: 147 cases were treated with RAC, i.e. 49 cases with R20C400 (10 mg R + 750 mg A + 200 mg C, twice daily), 48 cases with R40C400 (20 mg R + 750 mg A + 200 mg C, twice daily) and 50 cases with R40C800 (20 mg R + 750 mg A + 400 mg C, twice daily); 148 cases with treated with LAC (30 mg L + 750 mg A + 200 mg C, twice daily). RESULTS: According to intention-to-treat and per protocol analyses, the eradication rates were 88% and 91% with RAC and 78% and 81% with LAC; the eradication rates with R20C400, R40C400 and R40C800 were 94%, 81% and 86%, respectively, in the intention-to-treat analysis. In addition, the eradication rates for clarithromycin-sensitive strains with RAC and LAC were 98% and 89%, respectively, and for clarithromycin-resistant strains with RAC and LAC were 8.1% and 0%, respectively. CONCLUSIONS: The eradication rate was significantly higher with RAC than LAC. The eradication rate for clarithromycin-resistant strains was low in both groups, and an improved eradication rate could not be achieved by changing the dose of clarithromycin or proton pump inhibitor.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2001

Direct demonstration of rapid degradation of nuclear sterol regulatory element-binding proteins by the ubiquitin-proteasome pathway.

Sterol regulatory element-binding proteins (SREBPs) are synthesized as membrane-bound precursors and processed to generate transcriptionally active forms. The active SREBPs translocate to the nucleus, induce the expression of responsive genes, and are degraded very rapidly. Treatment with proteasome inhibitors elevates the amount of the endogenous nuclear SREBPs, but not the precursors, in HeLa cells. Nuclear forms of human SREBP-1a (amino acids 1-487) and SREBP-2 (amino acids 1-481), which are transiently expressed in stable Chinese hamster ovary cell lines (CHO-487 and -481), are also stabilized by proteasome inhibitors, suggesting that the nuclear SREBPs are likely to be substrates for the proteasome-dependent proteolysis. The stabilized nuclear SREBPs actively induce the expression of responsive genes including hydroxymethylglutaryl (HMG)-CoA synthase, fatty acid synthase, and the low density lipoprotein receptor. The rapid turnover of nuclear SREBP-1a is not affected by the intracellular sterol levels, and the half-life is estimated to be approximately 3 h. The nuclear SREBPs are found conjugated with a polyubiquitin chain. When this conjugation is inhibited by overexpression of mutant ubiquitin that is defective in polyubiquitination, the nuclear SREBPs are partly stabilized and induce the expression of the responsive gene, suggesting that the ubiquitin-conjugated SREBPs are substrates for the proteasome. Taken together, these results demonstrate that the ubiquitin-proteasome system degrades SREBPs and that this system controls the expression of SREBP-responsive genes.

Animals↗

PubMed2001

Proteolytic activation of SREBPs during adipocyte differentiation.

A member of sterol regulatory element-binding protein (SREBP) family, SREBP-1, is a key regulator of adipocyte differentiation. Expression of the SREBP-1 gene is induced during adipocyte differentiation, but proteolytic activation of the synthesized precursor form of SREBP-1 has not been well analyzed. The proteolytic processing of SREBPs is severely suppressed in sterol loaded culture cells. Here we report that a splicing isoform, SREBP-1a, is predominantly expressed in 3T3-L1 preadipocytes and adipocytes, and that the nuclear active form of SREBP-1 protein increases in adipocyte differentiation. We further show that the amount of nuclear SREBP-2 protein also increases despite no increase in SREBP-2 mRNA, suggesting that proteolytic cleavage of SREBPs is induced in lipid loaded adipocytes. Northern blot analyses reveal that mRNA levels for SREBP cleavage-activating protein (SCAP), Site-1 protease (S1P), and Site-2 protease (S2P), which participate in the proteolytic processing of SREBPs, are relatively unaffected in adipogenesis. These results demonstrate that SREBP-2 appears to promote adipocyte differentiation as well as SREBP-1 and that the proteolytic activation of SREBPs may be induced by an as-yet unidentified mechanism in lipid loaded adipocytes.

3T3 Cells↗

PubMed2001

Alternative splicing regulates the endoplasmic reticulum localization or secretion of soluble secreted endopeptidase.

A subfamily of zinc metalloproteases, represented by Neutral endopeptidase (EC ) and endothelin-converting enzyme, is involved in the metabolism of a variety of biologically active peptides. Recently, we cloned and characterized a novel member of this metalloprotease family termed soluble secreted endopeptidase (SEP), which hydrolyzes many vasoactive peptides. Here we report that alternative splicing of the mouse SEP gene generates two polypeptides, SEP(Delta) and SEP. After synthesis, both isoforms are inserted into the endoplasmic reticulum (ER) as type II membrane proteins. SEP(Delta) then becomes an ER resident, whereas SEP, which differs by only the presence of 23 residues at the beginning of its luminal domain, is proteolytically cleaved by membrane secretase(s) in the ER and transported into the extracellular compartment. An analysis of the chimeric proteins between SEP(Delta) and bovine endothelin-converting enzyme-1b (bECE-1b) demonstrated that the retention of SEP(Delta) in the ER is mediated by the luminal domain. In addition, the dissection of the chimeric bECE-1b/SEP insertion showed that its insertion domain is obviously responsible for its secretion. A series of mutagenesis in this region revealed that the minimal requirement for cleavage was found to be a WDERTVV motif. Our results suggest that the unique subcellular localization and secretion of SEP proteins provide a novel model of protein trafficking within the secretory pathway.

Alternative Splicing↗

PubMed2001

Mutational analyses of cysteine residues of bovine dihydrodiol dehydrogenase 3.

The cloning, bacterial expression and purification of bovine liver cytosolic dihydrodiol dehydrogenase 3 (DD3) cDNA (1330 bp in full length) using the pKK223-3 expression vector has been reported previously. Recombinant DD3 (rDD3) was characterized in terms of its substrate specificity and inhibitor sensitivity [Terada et al., Adv. Exp. Biol. Res. 414 (1997) 543-553]. The nucleotide sequence of DD3 cDNA completely matched with that of bovine liver-type prostaglandin F synthase [Suzuki et al., J. Biol. Chem. 274 (1999) 241-248]. In the present study, we succeeded in high level expression of rDD3 in Escherichia coli BL21 (DE3) using the pET28a expression vector. rDD3 was easily and quickly purified to apparent homogeneity by one-step column chromatography using Ni(2+)-affinity resin. Furthermore, rDD3 showed essentially the same substrate specificity and inhibitor sensitivity to that of purified liver DD3. To analyze the role of cysteines (145, 154, 188, 193 and 206) in the enzymatic activity of DD3, site-directed mutagenesis of DD3 using the polymerase chain reaction method was performed. Mutants (C145S, C154S, C188S, C193S and C206S) were analyzed for substrate specificity, cofactor binding and inactivation by disulfide (dithio-bis(2-nitrobenzoic acid), alkylating reagent (N-ethylmaleimide) and oxidants (naphthoquinone and H(2)O(2)) Results indicated that these five cysteines of rDD3 may not be directly involved in substrate or cofactor binding. Mutant C193S showed strong resistance to SH-reagents unlike wild-type DD3 (WT) or other mutants. Both the WT and the other mutants showed essentially the same sensitivity to SH-reagents. Cofactor (NADP(+)) protected mutants C145S, C188S and C206S from inactivation as well as WT, while NAD(+) was not protective. Our present results indicate that Cys193, which is located close to the NADP(+)-binding site, may be involved in the alteration of enzymatic activity.

Animals↗

PubMed2001

Site-directed mutagenesis studies of bovine liver cytosolic dihydrodiol dehydrogenase: the role of Asp-50, Tyr-55, Lys-84, His-117, Cys-145 and Cys-193 in enzymatic activity.

A previous report on the cloning, bacterial expression and purification of bovine liver cytosolic dihydrodiol dehydrogenase (DD3) cDNA (1,330 bp in full length) using pKK223-3 expression vector characterize the properties of the recombinant DD3 in the aspects of substrate specificity and inhibitor sensitivity (Terada et al., Adv. Exp. Biol. Res. 414 (1997) 543-53). The nucleotide sequence of this DD3 cDNA completely matches that of bovine liver-type prostaglandin F synthase (PGFS) (Suzuki et al., J. Biol. Chem. 274 (1999) 241-8). In the present study, a large amount of recombinant DD3 (rDD3) was expressed in Escherichia coli BL21 (DE3) with a pET28a expression vector. The recombinant DD3 (rDD3) was easily and quickly purified to an apparent homogeneity with one step column chromatography of Ni(2+)-affinity resin. The rDD3 showed essentially the same substrate specificity and inhibitor sensitivity as purified liver DD3 (DD3). To analyze the role of amino acid residues of DD3 in its enzymatic activity, site-directed mutagenesis of DD3 with PCR method was performed. The results of the analyses of these mutants in the aspects of substrate specificity and cofactor-binding suggested a variety of functions in the enzymatic activity: as an active site Tyr-55 may act as a general acid and Asp-50, Lys-84 and His-117 may play an important role in the control of protonation of Tyr-55 as a general acid in the dehydrogenase activity under higher pH conditions, though these residues may not be involved in reductase activity under lower pH conditions. Though the mutated DD3s (Cys to Ser) did not show significant differences in their substrate specificities, these mutants showed different sensitivities to SH-reagents. Present results indicate that Cys-193 may play an important role in the modulation of enzymatic activity under redox conditions generated with GSH+GSSG among five cysteines in DD3.

Alcohol Oxidoreductases↗

PubMed2001

Characterization of multiple Chinese hamster carbonyl reductases.

Carbonyl reductase (CR) is an enzyme which can catalyze the oxidoreduction of various carbonyl compounds in the presence of NAD(P)H. With the PCR method, using primers carrying the conserved nucleotide sequence among mammalian CRs, we isolated three different cDNAs (CHCR1, CHCR2 and CHCR3) which encode a unique carbonyl reductase from the Chinese hamster. The PCR products of CHCR1 and CHCR2 were clearly isolated with Bpu1102I, BspEI and XmaI restriction enzymes. The nucleotide-sequence of CHCR3 was completely different from those of CHCR1 and CHCR2. The predicted double-wound betaalphabetaalpha-structures of the CHCRs suggests the presence of a typical NADP(+)-binding motif and is similar to the corresponding region of 3alpha,20beta-hydroxysteroid dehydrogenase and mouse lung tetrameric carbonyl reductase. The deduced amino acid sequence of CHCR1 showed a high homology to CHCR2 (>96%) and the other mammalian CRs (>81%). However, CHCR3 showed a high homology to human CBR3 (>86%) and a relatively lower homology to the other CHCRs (<76%). Bacterial recombinant CHCRs showed typical carbonyl reductase activities towards 4-benzoylpyridine, 4-nitrobenzaldehyde and pyridine 4-carboxyaldehyde. These three CRs showed not only 3-keto reductase of steroids, but also 20-keto reductase. However, these CRs did not show any activity of 17-keto reductase activity. Both CHCR1 and CHCR2 have prostaglandin 9-keto reductase and 15-hydroxyprostaglandin dehydrogenase activities towards PGE(2) and PGF(2alpha) from the analyses of enzymatic reaction products. The results of Western blotting and RT-PCR suggest these CHCRs have a tissue-dependent-distribution in the Chinese hamster.

Alcohol Oxidoreductases↗

PubMed2001

The genetic factor in acute myocardial infarction with hypertension.

This study assessed the contribution of polymorphisms of angiotensin II (AngII) receptors and bradykinin B2 (BK-B2) receptor to hypertension and acute myocardial infarction (AMI) in a Japanese population: 150 subjects with essential hypertension, 150 subjects with AMI with/without hypertension, and 150 healthy, age- and sex-matched controls. Polymorphisms of the AngII type 1 receptor (1166 A/C) and type 2 receptor (3123 C/A), and the BK-B2 receptor (-58T/C, exon 1) were analyzed and significant differences of genotypes and allelic frequencies in the AngII type 2 receptor C/A and BK-B2 receptor -58T/C were found between the essential hypertension and control subjects. Further, a significantly higher incidence of the C allele of the BK-B2 receptor was seen in AMI subjects with hypertension compared with those without hypertension. Genetic variations in the AngII and BK-B2 receptors could prove to be significant pathophysiological mechanisms affecting essential hypertension and AMI, and genetic differences appear to be a new risk factor for these conditions.

Adult↗

PubMed2001

[Awareness of the health and defecation tendencies among college students by location of domicile].

In order to compare the food habits and defecation tendencies by region, a questionnaire survey was conducted of 1722 college women (18-20 years of age) living in Sapporo (146), Sendai (183), Osaka (1214), and Kumamoto (179). (1) When questioned about food habits, less than 58.5% of the respondents in the four groups considered their food intake to be sufficient to maintain their health. In regard to knowledge about their food intake requirements, the positive response was the highest in Sendai (85.8%), followed by Kumamoto (58.2%) and Osaka (50.9%) with the lowest in Sapporo (41.1%) (p < 0.01, among the four groups). (2) The students in Sendai, Osaka, Kumamoto and Sapporo, 96.2%, 93.5%, 92.9% and 92.5%, respectively, considered that constipation could affect their health (p < 0.05, among four groups). The percentage of those with regular bowel movements every day, tended to decrease in the order of Osaka (22.2%), Sapporo (21.2%) and Sendai (20.8%), with the lowest in Kumamoto (12.3%). Bowel movements of less than three times a week were reported by 24.7% in Sapporo, 24.0% in Sendai, 23.2% in Osaka and 22.3% in Kumamoto (p < 0.01, among the four groups). (3) Of those who defecated every day, in terms of time of day, the percentage was high between waking and after breakfast, with the highest percentage in Kumamoto (72.8%) and the lowest in Sapporo (61.2%) (p < 0.05, among the four groups). For subjects that responded that they should have a bowel movement every day, the highest percentage was in Osaka (91.0%) and the lowest was in Sapporo (83.9%) (p < 0.05, among the four groups).

Adolescent↗

PubMed2001

Pituitary chromophobe carcinoma with a low level of serum gonadotropin and an aspermatogenesis in a dog.

A 5-year-old male Shiba dog with progressive neurologic signs was examined by computed tomography (CT). A CT image of the brain disclosed a large, spherical high-density lesion in the thalamus and diencephalon. Serum LH, FSH and testosterone levels were all low. Macroscopically the large mass was connected with the sella turcia, and it was histopathologically diagnosed as a pituitary chromophobe carcinoma. An aspermatogenesis was observed in the testes. Therefore, it was suggested that the low levels of gonadotropin secretion from the pituitary gland due to the pituitary tumor resulted in the failure of maturation of spermatozoa and spermatids.

Adenocarcinoma↗

PubMed2001

Development of high-performance and rapid immunoassay for model food allergen lysozyme using antibody-conjugated bacterial magnetic particles and fully automated system.

A high-performance and rapid chemiluminescence immunoassay for model food allergen lysozyme, one of the major allergenic components in egg white, using antibody-conjugated bacterial magnetic particles and a fully automated system was developed. This system contains a reaction station, tip rack, and an eight-tip pipettor that is able to attach and detach a strong magnet to the tip surface. The immunoreaction time was shortened to 5 min, and the assay was completed within 20 min. The lower detection limit for lysozyme was 10 ng/mL. This system can be used to perform 24 samples in 60 min within 10% coefficient of variation.

Allergens↗

PubMed2001

A patient with type 1 diabetes mellitus and cerebellar ataxia associated with high titer of circulating anti-glutamic acid decarboxylase antibodies.

A 66-year-old Japanese woman presenting with recent onset of type 1 diabetes mellitus and cerebellar ataxia was admitted to our hospital. Physical examination on admission revealed coordinate disturbance due to cerebellar ataxia, and the laboratory examination showed marked hyperglycemia with ketosis and impaired insulin secretion. Anti-glutamic acid decarboxylase (GAD) antibodies in high titer were detected in patient's serum. Immunoblotting showed the patient's serum reacted with a 65 kDa protein in tissue extracts from rat pancreas and cerebellum, and immunohistochemical study produced positive immunostaining in the pancreatic islets of Langerhans, the axons of Purkinje cells and the nerve terminals in the granular layers of cerebellum of the rat. This is the first case presenting with concomitant type 1 diabetes and cerebellar ataxi associated with high titers of circulating anti-GAD antibodies which may play a critical role in the development of the diseases.

Aged↗

PubMed2001

Production of 8-OHdG and cytochrome c by cultured human mononuclear cells in patients with autoimmune thyroid disease.

Since oxidative stress is related to autoimmune thyroid disease, we studied the production of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and cytochrome c by culture of mononuclear cells from patients with Graves' disease and Hashimoto's thyroiditis. In patients with untreated Graves' disease, 8-OHdG and cytochrome c levels in culture supernatant of mononuclear cells were significantly higher than those of healthy control subjects, while the cytochrome c levels were significantly higher in patients with untreated Graves' disease and Hashimoto's thyroiditis than those of control subjects. Significant correlations between 8-OHdG and FT4, and cytochrome c were found. These results indicated that thyroid function has a potent influence on oxidative stress.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2001

Genetic background in patients with acute myocardial infarction.

The renin-angiotensin system is believed to play important roles in the development of acute myocardial infarction, and gene polymorphisms may also be involved. To investigate the genetic background in patients with acute myocardial infarction, we performed a case control study in a Japanese population. The study included 150 patients with acute myocardial infarction and 150 healthy, age- and sex-matched controls. We examined polymorphisms of angiotensin II type 1 receptor (1 166 A / C), type 2 receptor (3123 C / A), and bradykinin B2 receptor (-58 T / C) in these subjects. The allelic frequencies of angiotensin II type I receptor C and angiotensin II type 2 receptor A were significantly higher in the acute myocardial infarction subjects than in the control subjects, and this tendency was more significant in the younger patients. The combined ratios of angiotensin II type 1 receptor C and type 2 receptor A alleles in patients under 64 years old were significantly higher than in their older counterparts. However the total numbers of conventional coronary risk factors (hypertension, hypercholesterolemia, diabetes mellitus, and smoking) in individual subjects were not significantly different between younger and older patients. These polymorphisms were found to be involved in the development of acute myocardial infarction, particularly in the younger patients, and it was concluded that the incidence of acute myocardial infarction might be reduced by management from the genotypes.

Aged↗

PubMed2001

[Occurrence of upper gastrointestinal tract disease after Helicobacter pylori eradication].

Helicobacter pylori (H. pylori) infection is recognized to be a pathogen of various gastro-duodenal disease. Eradication therapy of H. pylori reduces the recurrence of gastro-duodenal ulcer, improves gastritis histologicaly, and is suggested to act an certain role in protection against gastric carcinogenesis. Although, several studies show uncomfortable results arise after H. pylori infection was cured. These studies suggest that gastro-esophageal reflux disease (GERD) and gastro-doudenal erosion may increase after successful eradication of H. pylori. Recently, adenocarcinoma of the gastric cardia and esophagus increase in incidence. Reflux esophagitis and Barrett's esophagus are recognized as precancerous lesion of esophageal adenocarcinoma. It is uncertain the association of newly occurrence of GERD after H. pylori eradication and increase of esophageal adenocarcinoma. Although GERD may lead to adenocarcinoma, long term observations is necessary after H. pylori eradication.

Adenocarcinoma↗