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Biomedical subjects

Akira Katayama

Publications and source records attributed to Akira Katayama.

18 recordsLinked to original sources
PubMed2005

Post-translational regulation of mercaptopyruvate sulfurtransferase via a low redox potential cysteine-sulfenate in the maintenance of redox homeostasis.

3-Mercaptopyruvate sulfurtransferase (MST) (EC 2.8.1.2), a multifunctional enzyme, catalyzes a transsulfuration from mercaptopyruvate to pyruvate in the degradation process of cysteine. A stoichiometric concentration of hydrogen peroxide and of tetrathionate (S(4)O(6)(2-)) inhibited rat MST (k(i) = 3.3 min(-1), K(i) = 120.5 microM and k(i) = 2.5 min(-1), K(i) = 178.6 microM, respectively). The activity was completely restored by dithiothreitol or thioredoxin with a reducing system containing thioredoxin reductase and NADPH, but glutathione did not restore the activity. On the other hand, an excess molar ratio dose of hydrogen peroxide inactivated MST. Oxidation with a stoichiometric concentration of hydrogen peroxide protected the enzyme against reaction by iodoacetate, which modifies a catalytic Cys(247), suggesting that Cys(247) is a target of the oxidants. A matrix-assisted laser desorption/ionization-time-of-flight mass spectrometric analysis revealed that hydrogen peroxide- and tetrathionate-inhibited MSTs were increased in molecular mass consistent with the addition of atomic oxygen and with a thiosulfate (S(2)O(3)(-)), respectively. Treatment with dithiothreitol restored modified MST to the original mass. These findings suggested that there was no nearby cysteine with which to form a disulfide, and mild oxidation of MST resulted in formation of a sulfenate (SO(-)) at Cys(247), which exhibited exceptional stability and a lower redox potential than that of glutathione. Oxidative stress decreases MST activity so as to increase the amount of cysteine, a precursor of thioredoxin or glutathione, and furthermore, these cellular reductants restore the activity. Thus the redox state regulates MST activity at the enzymatic level, and on the other hand, MST controls redox to maintain cellular redox homeostasis.

Animals↗
PubMed2005

The "eaves" technique for distal anastomosis in aortic arch replacement.

We describe the "eaves" technique, a new method for distal anastomosis in aortic arch replacement. The 1-cm wide eaves were created at the site 3 to 4 cm distal to the graft end. The graft was bound with vessel tape from the eaves to the site proximal to the origin of the first branch to make a working space above the eaves and to facilitate graft handling. Then the native descending aorta was sutured to the eaves easily. The eaves enabled a greater surface contact area between the graft and the inner wall of the aorta and reduced bleeding at the anastomosis.

Anastomosis, Surgical↗
PubMed2005

Evaluation of platelet indexes in patients with aortic aneurysm.

The purpose of this study was to investigate whether platelet indexes [platelet count, mean platelet volume (MPV), platelet-large cell ratio (P-LCR), and platelet distribution width (PDW)] could serve as diagnostic tools to evaluate the potential significance of platelet heterogeneity on thrombus formation. Blood samples were obtained from 54 patients with aortic aneurysm (AA; mean age 73 years; 40 males, 14 females), from 120 age-matched controls (AC; mean age 74 years; 61 males, 59 females), and from 38 young controls (YC; mean age 30 years; 20 males, 18 females). We measured the blood platelet indexes using an automated counter, as well as plasma D-dimer and thrombin-antithrombin III complex (TAT) using ELISA. The AA patients were divided into two groups, group A (platelet count more than 150 x 10(9)/l, n = 36) and group B (platelet count below 150 x 10(9)/l, n = 18). There was no difference in the platelet count between AC and YC. However, P-LCR was significantly higher (p = 0.0113) in AC. MPV and PDW were also higher, but not significantly so. The platelet count was not different between group A and AC. MPV (p = 0.0024 and <0.0001, respectively), P-LCR (p < 0.0012 and <0.0001, respectively) and PDW (p = 0.0006 and 0.0005, respectively) were significantly lower in group A than in group B and AC. The platelet indexes were significantly lower in the 54 AA patients than in the AC. There were significant inverse relationships between the platelet count and other indexes in the AC and 54 AA patients; however, no relationships were observed in group A, B and YC. The D-dimer and TAT levels were significantly higher in group B than in groups A and YC. In conclusion, these findings suggest that large platelets decrease rather than increase in patients with AA.

Adolescent↗
PubMed2005

Impact of ostial stenosis on the Doppler flow profiles in internal thoracic artery graft.

As ostial stenoses of internal thoracic artery (ITA) grafts rarely occur after coronary artery bypass grafting, little is known about their Doppler flow profile. This report describes changes in the Doppler flow of ITA grafts with ostial stenosis after surgical repair of the stenosis. A 54-year-old male underwent coronary artery bypass grafting (CABG) in which the left ITA was anastomosed to the left anterior descending coronary artery. The follow-up coronary angiography revealed an ostial 90% stenosis of the ITA. The patient underwent elective surgery during which the radial artery was interposed between the left subclavian artery and the ITA. Intraoperative ultrasonography was performed immediately before cut down of the ITA graft and again immediately after completion of all anastomoses. Both diastolic and systolic velocities and the velocity time integral increased more than 2-fold after the repair. Neither the diastolic-to-systolic peak velocity ratio nor the diastolic velocity time integral fraction showed remarkable change. These profiles were different from those reported previously for distal stenosis.

Constriction, Pathologic↗
PubMed2004

A new series of highly potent non-peptide bradykinin B2 receptor antagonists incorporating the 4-heteroarylquinoline framework. Improvement of aqueous solubility and new insights into species difference.

Introduction of nitrogen-containing heteroaromatic groups at the 4-position of the quinoline moiety of our non-peptide B(2) receptor antagonists resulted in enhancing binding affinities for the human B(2) receptor and reducing binding affinities for the guinea pig one, providing new structural insights into species difference. A CoMFA study focused on the diversity of the quinoline moiety afforded correlative and predictive QSAR models of binding for the human B(2) receptor but not for the guinea pig one. A series of 4-(1-imidazolyl)quinoline derivatives could be dissolved in a 5% aqueous solution of citric acid up to a concentration of 10 mg/mL. A representative compound 48a inhibited the specific binding of [(3)H]BK to the cloned human B(2) receptor expressed in Chinese hamster ovary cells with an IC(50) value of 0.26 nM and significantly inhibited BK-induced bronchoconstriction in guinea pigs even at 1 microg/kg by intravenous administration.

Animals↗
PubMed2004

Salivary flow rates during relaxing, clenching, and chewing-like movement with maxillary occlusal splints.

The purpose of this study was to test the hypothesis that the application of occlusal splints increases the diurnal salivary flow rate both in bruxism patients and in normal subjects. Salivary flow rates in 16 adult volunteers (8 bruxism patients and 8 sex- and age-matched control subjects) were measured with the spitting method. There was no significant difference in the salivary flow rate with or without splints between the control and bruxism groups. In all subjects, the salivary flow rates with splints were significantly higher than those without splints during relaxing, clenching, and chewing-like movement. The salivary flow rate during the chewing-like movement was significantly higher than that during relaxing and clenching, irrespective of splint application. The results suggest that maxillary occlusal splints might stimulate salivary secretion, particularly during chewing-like movement, in both bruxism patients and normal subjects.

Adult↗
PubMed2004

Movement of the lateral and medial poles of the working condyle during mastication in patients with unilateral posterior crossbite.

Patients with unilateral posterior crossbite often show reverse sequential jaw movement patterns on the frontal view during mastication on the crossbite side. Recent studies show that such patients are prone to suffer from temporomandibular joint (TMJ) disc displacement, particularly the lateral portion. The purpose of this study was to examine the movement of the lateral and medial poles of the working condyle during mastication in such patients. Subjects were 12 consecutive patients with unilateral posterior crossbites and without TMJ disc displacements and 12 normal subjects. An optoelectronic jaw-tracking system with 6 degrees of freedom was used to record the motion of the lateral and medial poles of the working condyle during mastication of standardized hard, gummy jelly. The data from the first 10 cycles were analyzed. The lateral and medial poles of the condyle on the crossbite side moved more in the medial direction and less in the lateral direction during mastication in the crossbite patients than the condyle in the normal subjects. The lateral pole of the working condyle moved more in the posterior and inferior directions and less in the anterior direction than the medial pole in all subjects. These results suggest that these condylar movements in patients with unilateral posterior crossbites might be related to the susceptibility to TMJ disc displacement, particularly the lateral portion.

Adolescent↗
PubMed2004

Relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions.

The purpose of this study was to examine the relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions. Twelve adult volunteers, including 4 bruxism patients, participated in this study. Portable pH monitoring, electromyography of the temporal muscle, and audio-video recordings were conducted during the night in the subjects' homes. Rhythmic masticatory muscle activity (RMMA) episodes were observed most frequently, with single short-burst episodes the second most frequent. The frequencies of RMMA, single short-burst, and clenching episodes were significantly higher during decreased esophageal pH episodes than those during other times. Both the electromyography and the decreased esophageal pH episodes were most frequently observed in the supine position. These results suggest that most jaw muscle activities, ie, RMMA, single short-burst, and clenching episodes, occur in relation to gastroesophageal reflux mainly in the supine position.

Adult↗
PubMed2004

Characterization and molecular cloning of cellobiose dehydrogenase from the brown-rot fungus Coniophora puteana.

Cellobiose dehydrogenase (CDH) was purified from the brown-rot fungus Coniophora puteana grown in culture containing crystalline cellulose as a carbon source. The purified enzyme gave a single band at 115 kDa on SDS-PAGE and showed a typical flavocytochrome absorption spectrum. The enzyme oxidized both cellobiose and cellooligosaccharides, but not their monomer, glucose, suggesting typical kinetic features of CDH. A cDNA encoding CDH was cloned by RT-PCR using primers designed from the consensus sequences of known CDHs from white-rot fungi. The cDNA consists of 2448 bp, including an open reading frame encoding the 18 amino acids of the putative signal peptide and the 756 amino acids of the mature protein. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) data for tryptic fragments of the purified C. puteana CDH were consistent with partial amino acid sequences of the mature protein deduced from the cloned cDNA. Moreover, the sequences contained common characteristics of CDH, i.e., two possible residues for a heme ligand (Met 64 and His 160), a flavin-binding motif, and two glucose-methanol-choline oxidoreductase motifs. This is the first cloning of CDH from a brown-rot fungus, and the results suggest structural and kinetic similarity of C. puteana CDH to white-rot fungal CDHs.

Journal Article↗
PubMed2004

Severe anterior open-bite case treated using titanium screw anchorage.

Anterior open bite is often caused by a downward rotation of the mandible and/or by excessive eruption of the posterior teeth. In such cases, it is difficult to establish absolute anchorage for molar intrusion by traditional orthodontic mechanics. This article reports the successful treatment of a severe skeletal anterior open-bite case using titanium screw anchorage. A female patient 33 years eight months of age had open bite of -7.0 mm and increased facial height. The titanium screws were implanted in both the maxilla and the mandible, and an intrusion force was provided with elastic chains for 13 months. After active treatment of 19 months, her upper and lower first molars were intruded about 3.0 mm each, and good occlusion was achieved. Her retrognathic chin and convex profiles were improved by an upward rotation of the mandible. Our results suggest that titanium screws are useful for intrusion of molars in anterior open-bite cases.

Adult↗
PubMed2003

Association between nocturnal bruxism and gastroesophageal reflux.

STUDY OBJECTIVE: To examine the relationship between nocturnal bruxism and gastroesophageal reflux. DESIGN: Controlled descriptive study and double-blind, placebo-controlled, clinical study. SETTING: Portable pH monitoring, electromyography, and audio-video recordings were conducted during the night in the subjects' home. PARTICIPANTS: Ten patients with bruxism and 10 normal subjects were matched for height, weight, age, and sex. They did not have symptoms of gastroesophageal reflux disease. INTERVENTION: Medication with a proton pump inhibitor (ie, a gastric-acid-inhibiting drug). MEASUREMENTS AND RESULTS: The bruxism group showed a significantly higher frequency of nocturnal rhythmic masticatory muscle activity (RMMA) episodes (mean +/- SD: 6.7 +/- 2.2 times per hour) and a higher frequency and percentage of time of gastroesophageal reflux episodes with a pH less than 4.0 and 5.0 (0.5 +/- 0.9 and 3.6 +/- 1.6 times per hour and 1.3% +/- 2.5% and 7.4% +/- 12.6%, respectively) than the control group (RMMA episodes: 2.4 +/- 0.9 times per hour; gastroesophageal reflux episodes: 0.0 +/- 0.0 and 0.1 +/- 0.3 times per hour and 0.0% +/- 0.0% and 0.0% +/- 0.0%, respectively). In the bruxism group, 100% of the gastroesophageal reflux episodes with a pH less than 3.0 and 4.0 included both an RMMA episode and an electromyographic burst, the duration of which was approximately 0.5 to 1.0 seconds, probably representing swallowing of saliva. The majority of gastroesophageal reflux episodes with a pH of 4.0 to 5.0 also included both an RMMA episode and an electromyographic burst in the control and bruxism groups (100% +/- 0.0% vs 70.7% +/- 16.5%), again probably due to swallowing of saliva. The remaining minority of gastroesophageal reflux episodes with a pH of 4.0 to 5.0 contained only an electromyographic burst (swallowing of saliva). The frequency of RMMA episodes after the release of the medication from the proton pump inhibitor, which increased the gastric and esophageal pH, was significantly lower than that after administration of the placebo in the control and bruxism groups (1.0 +/- 0.6 vs 1.9 +/- 3.2 times per hour, and 3.7 +/- 1.9 vs. 6.0 +/- 2.2 times per hour, respectively). CONCLUSIONS: Nocturnal bruxism may be secondary to nocturnal gastroesophageal reflux, occurring via sleep arousal and often together with swallowing. The physiologic link between bruxism and the increase in salivation needs to be investigated.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2003

Relationship between coagulation cascade, cytokine, adhesion molecule and aortic aneurysm.

OBJECTIVES: Patients with aortic aneurysm (AA) were in the chronic inflammatory condition and are often combined with disseminated intervascular coagulation. Recent studies demonstrated that atherosclerosis was inflammatory disease. AA and severe atherosclerosis with ulcer formation contain macrophages and T lymphocytes and accelerate the production of interleukin (IL)-2, which activates lymphocytes and lead to further adhesion of leukocytes. This study was designed to clarify the coagulation condition, cytokine, adhesion molecule, and collagen turnover in patients with AA and finally their relationship with the aneurysmal size. METHODS: Thrombin-antithrombin III complex (TAT), plasma D-dimer, serum type III procollagen peptide (PIIIP), serum soluble IL-2 receptor (sIL-2R), Free tissue factor pathway inhibitor (TFPI), and soluble intercellular adhesion molecule (ICAM-1) were measured preoperatively around the same period when computed tomography (CT) was taken in 17 patients with AA (mean age: 72.2 years). Age-matched (mean age:70 years) volunteers were served as control. Maximum aneurysmal size was measured by CT and aneurysmal volume was also calculated from CT. RESULTS: AA patients showed significantly higher level in preoperative TAT and D-dimer compared to control (TAT: control 2.5+/-1.2 ng/ml, pre 7.2+/-4.5,ng/ml; P=0.0001; D-dimer: control 107+/-46 U/ml, pre 420+/-256 U/ml; P=0.0001). Cytokine also showed higher level preoperatively (sIL-2R: control 398+/-132 U/ml, pre 735+/-260 U/ml; P=0.0001). TFPI showed higher value preoperatively (control 22.9+/-4.9 ng/ml, pre 30.4+/-6.9 ng/ml; P=0.003). PIIIP (collagen turnover) showed no difference between the groups (P=0.0057) and neither did ICAM-1(P=0.0087). TAT (r=0.799, P=0.0001), D-dimer (r=0.56, P=0.0193), sIL-2R (r=0.709, P=0.0021), PIIIP (r=0.561, P=0.00239), and sICAM-1 (r=0.505, P=0.046) level showed positive correlation with aortic aneurysmal size and also TAT D-dimer, and sIL-2R levels were positively correlated with aneurysmal volume (r=0.714 P=0.0013, r=0.556 P=0.00204, r=0.693 P=0.0029, respectively). CONCLUSIONS: AA patients were in the hypercoagulation and inflammatory condition. Aneurysmal size was well correlated with TAT, D-dimer, sIL-2R, PIIIP, and sICAM-1, suggesting that these markers could be good diagnostic and monitoring tool for the disease progression.

Aged↗
PubMed2003

[Area distribution of out-issued prescriptions from Saiseikai Kurihashi Hospital and behavior patterns of outpatients for selection of pharmacy].

The area distribution of out-issued prescriptions for outpatients in Saiseikai Kurihashi Hospital was surveyed over 6 months from the first day of out-issue. Behavior patterns of outpatients in the selection of pharmacy were also investigated. Our survey included the out-issued prescriptions in eight surrounding newly established pharmacies together with the first out-issue. Computer simulation indicated that 70% of the outpatients selected the surrounding pharmacies when they received their out-issued prescriptions the first time. However, the percentage of surrounding pharmacies selected by the patients decreased to 60% the second time, and then again increased to 80% the third time. The results suggest that most outpatients use surrounding pharmacies, although they try to use the pharmacies near their homes for a time.

Choice Behavior↗
PubMed2002

Systematic search for zinc-binding proteins in Escherichia coli.

A systematic search for Escherichia coli proteins with the zinc-binding activity was performed using the assay of radioactive Zn(II) binding to total E. coli proteins fractionated by two methods of two-dimensional gel electrophoresis. A total of 30-40 radioactive spots were identified, of which 14 have been assigned from N-terminal sequencing. In addition to five known zinc-binding proteins, nine zinc-binding proteins were newly identified including: acetate kinase (AckA), DnaK, serine hydroxymethyltransferase (GlyA), transketolase isozymes (TktA/TktB), translation elongation factor Ts (Tsf), ribosomal proteins L2 (RplB), L13 (RplM) and one of S15 (RpsO), S16 (RpsP) or S17 (RpsQ). Together with about 20 known zinc-binding proteins, the total number of zinc-binding proteins in E. coli increased up to more than 30 species (or more than 3% of about 1000 proteins expressed under laboratory culture conditions). The specificity and affinity of zinc-binding were analysed for some of the zinc-binding proteins.

Bacterial Proteins↗
PubMedDate not supplied

Relationship between hemostatic markers and circulating biochemical markers of collagen metabolism in patients with aortic aneurysm.

Our objective was to determine the relationship between plasma levels of hemostatic molecular markers--D-dimer and thrombin-antithrombin III complex (TAT)--and circulating biochemical markers of collagen metabolism--aminoterminal propeptide of type III procollagen (PIIIP) and carboxyterminal propeptide of type I procollagen (PICP)--in patients with aortic aneurysm. The subjects were 43 patients with aortic aneurysm (AA; mean age 71 years) and 26 age-matched controls (mean age 75 years). The mean D-dimer, TAT and PIIIP levels were higher in the patients than in the controls (p < 0.0001, 0.0001 and 0.012, respectively), while the mean PICP level was similar to that in the controls. Increased D-dimer had a significant correlation with PIIIP (r = 0.412, p = 0.006) and PICP (r = 0.342, p = 0.0246), while TAT correlated with PIIIP (r = 0.3194, p = 0.0374), but not with PICP. There was also a significant correlation (r = 0.306, p = 0.0463) between PIIIP and PICP. As shown by the significant positive correlations among D-dimer, TAT and PIIIP, accelerated fibrinolysis and thrombogenesis induce an increase of collagen degradation and procollagen synthesis in atherosclerotic lesions. These findings show that D-dimer and TAT, especially the former, may be useful markers to monitor the progression and predict the prognosis of AA.

Aged↗