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Biomedical subjects

T Yamazaki

Publications and source records attributed to T Yamazaki.

At least 109 records · Page 6Linked to original sources
PubMed2001

The DD genotype of angiotensin converting enzyme polymorphism is a risk factor for coronary artery disease and coronary stent restenosis in Japanese patients.

Stent implantation has decreased the incidence of restenosis after coronary intervention, but has not eliminated it. The contribution of the angiotensin-converting enzyme (ACE) genotype to the development of coronary artery disease and restenosis after coronary stenting was investigated in 67 Japanese patients in whom 103 lesions in which stents had been successfully implanted were assessed by quantitative coronary angiography, before, immediately after coronary stenting, and during follow-up. The distribution of the patients with the DD, ID, and II genotypes was 13%, 54%, and 33%, respectively. The prevalence of multivessel disease in the DD genotype was significantly higher (DD genotype: 78%; ID genotype: 58%; II genotype: 27%, chi2=8.13, p=0.016) and the late loss in the DD genotype (1.43+/-0.96 mm) was significantly greater (ID genotype: 0.78+/-0.98 mm and II genotype: 0.79+/-0.88 mm, p<0.05 vs DD genotype). However, there was no significant difference in the restenosis rate among the 3 genotypes. The present study in Japanese patients indicates that the DD genotype is associated with more extensive coronary artery disease and progression of the inward remodeling within the stented lesion, which is primarily caused by neointimal hyperplasia.

Aged↗
PubMed2001

Biodegradation of formaldehyde by a formaldehyde-resistant bacterium isolated from seawater.

A formaldehyde-tolerant bacterium designated as a DM-2 strain was used to biodegrade formaldehyde. The cells, precultivated in the presence of 400 ppm of formaldehyde, were able to degrade formaldehyde in a minimal medium supplemented with up to 400 ppm of formaldehyde in the presence of 3% NaCl. The rate of formaldehyde degradation achieved in this study was 45 ppm/h when the DM-2 culture's optical density at 660 nm was 1.2.

Bacteria↗
PubMed2001

Intraosseous meningioma of the posterior fossa--Case report.

A 62-year-old male presented with a rare intraosseous meningioma with intradural extension manifesting as frequent vomiting and floating sensation that had persisted for 3 months. Neuroimaging detected a mass lesion that was mainly located extradurally in the right posterior fossa with a daughter lesion inside the dura. He underwent surgical excision of the mass lesion. Craniectomy exposed the main lesion of the tumor just beneath the thinned outer table of the skull, and in the extradural space, with the daughter lesion penetrating the dura. Both portions of the tumor were resected. There was no attachment to the adjacent dura mater. Histological examination showed meningotheliomatous meningioma containing scattered bony tissue. This intraosseous meningioma probably originated from the occipital bone with a small intradural extension caused by mechanical compression.

Cerebral Angiography↗
PubMed2001

Content analysis of group work sessions in the context of an educational program for inpatient diabetes patients.

This study investigated the changes in emotions and attitudes of diabetic patients as observed in group work sessions linked to an inpatient diabetic educational program. Using content analysis of transcripts from Sessions 1 and 3 of 8 selected groups (40 patients), in Session 1 negative emotions or attitudes such as anxiety, remorse, or self-blame, a lack of understanding of diabetes, along with a willingness to undertake self-care were frequently expressed. In Session 3, more positive emotions and attitudes towards self-care (willingness, specific plans, and resolutions), satisfaction, and relief or hope were frequently expressed. These results suggest that the patients participating in the group work sessions moved toward adaptation to diabetes, although the effects of the group work were not separated from those of the inpatient educational program.

Adaptation, Psychological↗
PubMed2001

[Effectiveness of a new toothbrush with irrigation and suctioning capabilities (ty e-Brush) for removing supragingival plaque].

Patients with dysphagia typically have poor oral health. Because of improper swallowing, they cannot easily and safely clean their mouths. As a solution for such a problem, a manual toothbrush with both irrigation and suctioning functions has been developed, called the "e-Brush". The purpose of this study was to evaluate the cleaning effectiveness of the new e-Brush (9 mm and 11 mm in bristle length) for removing supragingival plaque, compared with a conventional toothbrush, GUM # 211 by Butler. In this study, 12 subjects (12 female of average age 20.6) were selected, and plaque control record (PCR) and scrubbing method were used. The following results were obtained: 1. Significant differences (p < 0.05) were recognized between e-Brush/9 mm (55.54 +/- 18.27%) and the others (e-Brush/11 mm: 30.88 +/- 8.14%, GUM # 211: 35.42 +/- 9.32%). 2. Bristles 9 mm in length were more effective than 11 mm bristles (p < 0.05). 3. Irrigation/suctioning function is more effective than the conventional tooth-brushing method. 4. The irrigation function of e-Brush was meritorious in making almost all users comfortable. These results suggest that this new oral hygiene device, "e-Brush/9 mm", is effective for improving oral care management for patients with dysphagia.

Adult↗
PubMed2001

[Narrowing of the dental pulp cavity in patients undergoing long-term administration of steroids].

The purpose of this study was to examine narrowing of the dental pulp cavity in patients undergoing long-term administration of steroids, by means of intraoral radiographs. The subjects were 20 patients under long-term steroid treatment (the steroid group), and 15 patients who were not receiving steroids (the non-steroid group), who visited the Clinic for Persons with Disabilities, University Hospital, Faculty of Dentistry, Tokyo Medical and Dental University, between April 1994 and March 2000. The dental pulp cavity was divided into the coronal area and the root area. Narrowing of each area was classified into three stages by means of intraoral radiographs (0, none; 1, moderate; 2, severe). Maxillary and mandibular dentition was divided, for purposes of analysis, into anterior, premolar, and molar areas, respectively. The narrowing of each part was statistically compared between the steroid group and the non-steroid group, using the Mann-Whitney U-test. Mean age +/- SD of the steroid group and the non-steroid group was 50.5 +/- 17.3 and 51.8 +/- 14.1, respectively. There was no significant difference in mean age between the steroid group and the non-steroid group (t-test). Narrowing of the dental pulp cavity in the steroid group was significantly greater than in the non-steroid group, except in the root area of the molar part. Since there was no significant difference in mean age between the steroid group and the non-steroid group, the greater narrowing in the steroid group was concluded to be attributable to the long-term administration of steroids.

Adolescent↗
PubMed2001

[Clinical effects of combination therapy with cefozopran and amikacin for infections in patients with hematological disorders].

Cefozopran (CZOP) and amikacin (AMK) were used concomitantly to treat infections complicated by hematological diseases. A total of 103 subjects were evaluated, and the all over efficacy rate was 69.9%. Acute leukemia was found in the largest number of patient, 57, followed by 29 cases of malignant lymphoma and 7 cases of myelodysplastic syndrome. By type of infection, patients having unknown origin were the largest in number, being 66, and the efficacy rate was 71.2%. The efficacy rates for sepsis, pneumonia and upper respiratory infection were 42.9% (7 cases), 71.4% (14 cases) and 90% (10 cases) respectively. The efficacy rates by neutrophil counts before administration of CZOP and AMK and at 1 week after administration were both 53.3% in the group of less than 100/microliter, both 60% in the group of less than 500/microliter. The efficacy rate by neutrophil counts at 1 week after administration was 58.6% in the group of less than 100/microliter. The efficacy rate was 75.4% in the group of granulocyte colony stimulating factor (G-CSF) concomitant usage, and 61.9% in the group of non-concomitant usage group. The efficacy rates by serum albumin levels before administration of CZOP and AMK and at 1 week after administration were both 92.9% in the group of over than 4 g/dl, both 50% in the group of less than 3 g/dl. Concomitant treatment with CZOP and AMK exhibited a high level of safety and efficacy rates in infections complicated by hematological diseases.

Adult↗
PubMed2001

[Postoperative chemotherapy with a novel oral anticancer drug composed of tegafur, gimeracil and oteracil potassium to curability C scirrhus type gastric cancer].

We report the a case of 60-year-old male whose final finding was curability C and stage IV scirrhus type gastric cancer because of N3, CY1 and DM (+) treated with a novel oral anticancer drug composed of tegafur (FT), Gimeracil (CDHP) and Oteracil Potassium (Oxo) in a molar ratio of 1:04:1 after operation. This drug was administered orally twice daily after meals at a dose of 80 mg/body/day. One cycle consisted of consecutive administration for 28 days and 14 days rest, and this treatment cycle was repeated twice. Postoperative abdominal CT showed swollen paraaortic lymph nodes regarded as metastasis. However, they were reduced after 1 cycle and remained so. The serum carcinoembryonic antigen (CEA) level had decreased after 1 cycle. The patient's performance status (PS) had also recovered without severe side effects. It was considered that this anticancer drug composed of FT, CDHP and Oxo was effective to scirrhus type gastric cancer and useful as an adjuvant chemotherapy in view of the patient's living quality.

Administration, Oral↗
PubMed2000

Identification of the phospholipid-binding site of human beta(2)-glycoprotein I domain V by heteronuclear magnetic resonance.

To understand the mechanism of the interaction between human beta(2)-glycoprotein I (beta(2)-GPI) and negatively charged phospholipids, we determined the three-dimensional solution structure of the fifth domain of beta(2)-GPI by heteronuclear multidimensional NMR. The results showed that the molecule is composed of well-defined four anti-parallel beta-strands and two short alpha-helices, as well as a long highly flexible loop. Backbone dynamic analysis demonstrated significant mobility of the flexible loop on a subnanosecond time scale. Structural modeling of the nicked fifth domain, in which the Lys317-Thr318 peptide bond was specifically cleaved, revealed the importance of this long C-terminal loop for the interaction between beta(2)-GPI and negatively charged phospholipids. A titration experiment with the anionic surfactant SDS showed that this highly mobile loop, as well as the short beta-hairpin between betaC and betaD strands, which is rich in positively charged residues, specifically interact with the surfactant. The mobile loop, together with the surrounding positively charged residues, probably construct the binding site for negatively charged phospholipids such as cardiolipin.

Amino Acid Sequence↗
PubMed2000

Regulation of the successive reaction catalyzed by rat neuronal nitric oxide synthase.

The rat neuronal nitric oxide synthase (nNOS) catalyzes two monooxygenase reactions successively from L-arginine (L-Arg) to L-citrulline (L-Cit) via N(omega)-hydroxy-L-arginine (OH-Arg) without most of OH-Arg leaving the substrate-binding site. In the steady-state reaction conditions, the amount of OH-Arg produced is about 1/30-1/50 that of L-Cit. We found in this study using nNOS purified from an Escherichia coli expression system that the ratio of the amount of OH-Arg to L-Cit (OH-Arg/L-Cit) increased to about 1 at low concentration of NADPH. In one cycle of the nNOS reaction, the decrease in NADPH concentration was found to reduce the rates of two monooxygenase reactions but had little effect on the rate constant of OH-Arg dissociation from the enzyme. The addition of NADP(+), the competitive inhibitor for NADPH, caused the decrease in the rates of monooxygenase reactions in a single cycle of the reaction and the increase in the ratio of OH-Arg/L-Cit in the steady state. At low CaM concentrations, the ratio of OH-Arg/L-Cit was about the same as that at high CaM. In a single cycle of the nNOS reaction, the rate of monooxygenation was not altered by the CaM concentration but the amount of metabolized L-Arg decreased with the decrease in CaM concentration, showing that the amount of active nNOS was regulated by complex formation between nNOS and CaM. It becomes clear that there are two regulatory mechanisms for the successive reaction of nNOS. One controls the rates of monooxygenations and the other controls the amount of active species of nNOS.

Animals↗
PubMed2000

High precision NMR structure of YhhP, a novel Escherichia coli protein implicated in cell division.

YhhP, a small protein of 81 amino acid residues encoded by the yhhP gene in the Escherichia coli database, is implicated in cell division although the precise biological function of this protein has not been yet identified. A variety of microorganisms have similar proteins, all of which contain a common CPxP sequence motif in the N-terminal region. We have determined the three-dimensional solution structure of YhhP by NMR spectroscopy in order to obtain insight into its biological function. It folds into a two-layered alpha/beta-sandwich structure with a betaalphabetaalphabetabeta fold, comprising a mixed four-stranded beta-sheet stacked against two alpha-helices, both of which are nearly parallel to the strands of the beta-sheet. The CPxP motif plays a significant structural role in stabilizing the first helix as a part of the new type N-capping box where the Cys-Pro peptide bond adopts a cis configuration. The structure of YhhP displays a striking resemblance to the C-terminal ribosome-binding domain of translation initiation factor IF3 (IF3C). In addition, the surface charge distribution of the RNA-recognition helix of IF3C is nearly the same as that of the corresponding helix of YhhP. These results suggest a structure-based hypothesis in which binding to an RNA target plays an essential role in the function of this ubiquitous protein.

Amino Acid Sequence↗
PubMed2000

Accumulation and aggregation of amyloid beta-protein in late endosomes of Niemann-pick type C cells.

There is growing evidence suggesting that cholesterol metabolism is linked to susceptibility to Alzheimer's disease by influencing amyloid beta-protein (Abeta) metabolism. However, the precise cellular linkage sites between cholesterol and Abeta have not yet been clarified. To address this issue, we investigated Niemann-Pick type C (NPC) model cells and NPC mutant cells, which showed aberrant cholesterol trafficking. We observed a remarkable Abeta accumulation in late endosomes of both NPC model cells and mutant cells where cholesterol accumulates and a significant accumulation in the NPC mouse brain. This Abeta accumulation was independent of its constitutive secretion and production through an endocytic pathway. In addition, it is characterized by a marked predominance of Abeta42 and insolubility in SDS, suggesting the presence of aggregated Abeta in late endosomes. Most importantly, Abeta accumulation is coupled with the cholesterol levels in late endosomes. Thus, late endosomes of NPC cells are a novel pool of aggregated Abeta42 as well as cholesterol, suggesting a direct interaction between aggregated Abeta and cholesterol.

Amyloid beta-Peptides↗
PubMed2000

Structural understanding of the allosteric conformational change of cyclic AMP receptor protein by cyclic AMP binding.

Cyclic AMP receptor protein (CRP) plays a key role in the regulation of more than 150 genes. CRP is allosterically activated by cyclic AMP and binds to specific DNA sites. A structural understanding of this allosteric conformational change, which is essential for its function, is still lacking because the structure of apo-CRP has not been solved. Therefore, we performed various NMR experiments to obtain apo-CRP structural data. The secondary structure of apo-CRP was determined by analyses of the NOE connectivities, the amide proton exchange rates, and the (1)H-(15)N steady-state NOE values. A combination of the CSI-method and TALOS prediction was also used to supplement the determination of the secondary structure of apo-CRP. This secondary structure of apo-CRP was compared with the known structure of cyclic AMP-bound CRP. The results suggest that the allosteric conformational change of CRP caused by cyclic AMP binding involves subunit realignment and domain rearrangement, resulting in the exposure of helix F onto the surface of the protein. Additionally, the results of the one-dimensional [(13)C]carbonyl NMR experiments show that the conformational change of CRP caused by the binding of cyclic GMP, an analogue of cyclic AMP, is different from that caused by cyclic AMP binding.

Allosteric Regulation↗
PubMed2000

Identification of a novel inhibitor specific to the fungal chitin synthase. Inhibition of chitin synthase 1 arrests the cell growth, but inhibition of chitin synthase 1 and 2 is lethal in the pathogenic fungus Candida albicans.

As in Saccharomyces cerevisiae, the pathogenic fungus Candida albicans harbors three chitin synthases called CaChs1p, CaChs2p, and CaChs3p, which are structurally and functionally analogous to the S. cerevisiae ScChs2p, ScChs1p, and ScChs3p, respectively. In S. cerevisiae, ScCHS1, ScCHS2, and ScCHS3 are all non-essential genes; only the simultaneous disruption of ScCHS2 and ScCHS3 is lethal. The fact that a null mutation of the CaCHS1 is impossible, however, implies that CaCHS1 is required for the viability of C. albicans. To gain more insight into the physiological importance of CaCHS1, we identified and characterized a novel inhibitor that was highly specific to CaChs1p. RO-09-3143 inhibited CaChs1p with a K(i) value of 0.55 nm in a manner that was non-competitive to the substrate UDP-N-acetylglucosamine. RO-09-3143 also hampered the growth of the C. albicans cells with an MIC(50) value of 0.27 microm. In the presence of RO-09-3143, the C. albicans cells failed to form septa and displayed an aberrant morphology, confirming the involvement of the C. albicans Chs1p in septum formation. Although the effect of RO-09-3143 on the wild-type C. albicans was fungistatic, it caused cell death in the cachs2Delta null mutants but not in the cachs3Delta null mutants. Thus, it appears that in C. albicans, inhibition of CaChs1p causes cell growth arrest, but simultaneous inhibition of CaChs1p and CaChs2p is lethal.

Aminoglycosides↗
PubMed2000

Rational design of highly diastereoselective, organic base-catalyzed, room-temperature Michael addition reactions.

Via the rational design of a single-preferred transition state, stabilized by electron donor-acceptor-type attractive interactions, structural and geometric requirements for the corresponding starting compounds have been determined. The Ni(II) complex of the Schiff base of glycine with o-[N-alpha-picolylamino]acetophenone, as a nucleophilic glycine equivalent, and N-(trans-enoyl)oxazolidin-2-ones, as derivatives of an alpha,beta-unsaturated carboxylic acid, were found to be the substrates of choice featuring geometric/conformational homogeneity and high reactivity. The corresponding Michael addition reactions were found to proceed at room temperature in the presence of catalytic amounts of DBU to afford quantitatively the addition products with virtually complete diastereoselectivity. Acidic decomposition of the products followed by treatment of the reaction mixture with NH4OH gave rise to the diastereomerically pure 3-substituted pyroglutamic acids.

Catalysis↗
PubMed2000

Extended-range glucose sensor employing engineered glucose dehydrogenases.

An enzyme glucose sensor with an expanded dynamic range was constructed using a novel strategy. This strategy was based on a new concept of utilizing protein-engineered enzymes with a different Michaelis constant, which allows for the expanded dynamic range. We used the engineered Escherichia coli pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) of which His775 was substituted for Asp which showed an increased Km value (25-fold). We first constructed the composite colorimetric analytical system employing the wild-type PQQGDH and His775Asp and evaluated its dynamic range. The composite colorimetric analytical system was constructed and showed a wide dynamic range of 0.5-30 mM with less than +/-5% error. The composite colorimetric analytical system, an extended-range colorimetric analytical system, enabled the determination of the concentration of glucose over a 30-fold range that could not have been achieved using the single colorimetric analytical system. Furthermore, we have demonstrated the composite amperometric glucose sensor employing the combination of His775Asn and His775Asp. The extended-range glucose sensor acquired not only the expanded dynamic range (3-70 mM) that covered both dynamic ranges of the single enzyme sensors but also the narrower substrate specificity of glucose due to the inherited property of engineered enzymes.

Biosensing Techniques↗