PubMed Health⌕ Search

Biomedical subjects

Atsushi Kobayashi

Publications and source records attributed to Atsushi Kobayashi.

At least 19 recordsLinked to original sources
PubMed2006

[Effect of oral health care program on the oral function of the elderly].

In order to prepare a new prevention program under the long term care insurance from the fiscal year 2006, we have organized an oral health care program for the elderly in a town of Kagoshima prefecture. We conducted a series of oral health education, i.e., instruction on brushing and flossing, and oral function exercises. Before and after the three months program, we evaluated the unstimulated and stimulated salivary flow rate, the counts of S. mutans, the counts of repetitive saliva swallowing test (RSST), bilateral bite force and the number of permanent teeth and artificial teeth. According to the results, a statistically significant improvement was observed in RSST and the unstimulated and stimulated salivary flow rate, but not in the S. mutans level and bite force. The present research suggests the effectiveness of the oral health care program for the aged. A larger sized and longer period intervention will be necessary in order to validate our findings.

Aged↗
PubMed2006

A prostaglandin E2 receptor subtype EP1-selective antagonist, ONO-8711, suppresses 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis.

We previously reported that certain cyclooxygenase (COX) inhibitors could inhibit chemically induced tongue carcinogenesis. In the present study, we investigated the effects of prostaglandin E(2) (PGE(2)) receptor EP(1)-selective antagonist ONO-8711 on 4-nitroquinoline 1-oxide (4-NQO)-induced oral carcinogenesis to know whether an EP(1) receptor involves in oral carcinogenesis. Male Fischer 344 rats were given drinking water containing 4-NQO for 8 weeks (20 p.p.m. for the initial 2 weeks, 25 p.p.m. for 2 weeks, and then 30 p.p.m. for 4 weeks). After 4-NQO treatment, animals were given 400 or 800 p.p.m. ONO-8711 containing diets for 23 weeks. The incidence of tongue squamous cell carcinomas (SCC) in the 4-NQO-treated rats was 64%, while that in the rats given ONO-8711 after 4-NQO exposure was 29 (P<0.05) and 29% (P<0.05) in the 400 and 800 p.p.m. of ONO-8711, respectively. The multiplicity of tongue cancer was also smaller in the 4-NQO + ONO-8711 (400 p.p.m. ONO-8711, 0.35 +/- 0.61; and 800 p.p.m. ONO-8711, 0.29 +/- 0.47; P<0.05), when compared with the 4-NQO alone group (0.88 +/- 0.88). Feeding with ONO-8711 significantly reduced PGE(2) level and cell proliferation activity in the non-tumorous epithelium of the tongue. Also, treatment with ONO-8711 resulted in the decrease in EP(1) immunohistochemical expression in the tongue lesions induced by 4-NQO. The results suggest that EP(1) receptor involves in oral carcinogenesis, and that an EP1-selective antagonist ONO-8711 exerts the cancer chemopreventive effects through the suppression of EP(1) expression, PGE(2) biosynthesis and cell proliferation.

4-Nitroquinoline-1-oxide↗
PubMed2006

Mixed-valence two-legged MX-ladder complex with a pair of out-of-phase charge-density waves.

A novel two-legged MX-ladder complex {[(dien)PtIVBr2-bpy-PtII(dien)]Br4.2H2O}infinity was synthesized and analyzed by single-crystal X-ray diffraction method and Raman and diffuse reflectance spectra. The electronic structure on two-legged MX-ladder is a pair of out-of-phase charge-density-waves state within each ladder, and these pairs of CDWs are also ordered from ladder to ladder. The intervalence charge-transfer (PtII to PtIV) excitation energy is significantly larger than that in the MX-chain system because of the intersite Coulomb repulsion along the rung.

Journal Article↗
PubMed2006

Most stable metallic phase of the mixed-valence MMX-chain, Pt2(dtp)4I (dtp = C2H5CS2-), in purely d-electronic conductors based on the transition-metal complex.

The electrical resistivity and X-ray oscillation photograph measurements for an MMX-chain complex, Pt2(dtp)4I (dtp = C2H5CS2-), under high pressure were performed. We observed the most stable metallic phase (TMI = 70 K, under 2.2 GPa) in the 1-D purely d-electronic conductors and pressure-induced metal-insulator transition including the structural phase transition at 3.0 GPa.

Journal Article↗
PubMed2006

[Functional improvement program of musculoskeletal system of the elderly in an isolated island of Kagoshima prefecture].

Under the coming amendment of long term care insurance (LTCI), the preventive activities will be more strengthened in order to ameliorate the quality of life (QOL) levels of the slightly frail elderly and then to rationalize the LTCI expenditures. The functional training of the musculoskeletal system is regarded as especially important. In order to validate its effectiveness and availability in a rural setting, we organized a physical fitness program for the slightly frail elderly in an isolated island of Kagoshima prefecture. According to the results of our preliminary study, statistically significant improvement was observed for some items of the physical fitness level, but not for life style, activities of daily living (ADL), instrumental activities of daily living (IADL) levels or Frenchay Activities Index. In addition to the relatively small number of participants, it is thought that physical fitness training alone cannot increase the elderly activity volume. Further studies are necessary to clarify the usefulness of physical training on the ADL/IADL level of the elderly.

Activities of Daily Living↗
PubMed2006

Direct determination of low-dimensional structures: synchrotron X-ray scattering on one-dimensional charge-ordered MMX-chain complexes.

A powerful method to determine the hidden structural parameters in functional molecules has been developed. Local valence arrangements that dominate the material properties are sometimes not three-dimensionally ordered. This method that comprises diffuse X-ray scattering and resonant X-ray scattering is suitable in such cases. Using this method, we present clear evidence of the low-dimensional valence arrangement in two halogen-bridged one-dimensional metal complexes, so-called MMX chains. This family allows us to control many physical and structural parameters by chemical substitution of bridging halogen, counterions, or metal ions, and one of our samples carries an unusual metallic phase. It is demonstrated with this complex that the present method makes it possible to have microscopic insight to low-dimensionally ordered systems.

Journal Article↗
PubMed2006

Synthesis of a one-dimensional metal-dimer assembled system with interdimer interaction, M2(dtp)4 (M = Ni, Pd; dtp = dithiopropionato).

A metal-dimer assembled system, M(2)(dtp)(4) (M = Ni, Pd; dtp = dithiopropionate, C(2)H(5)CS(2-)), was synthesized and analyzed by the X-ray single-crystal diffraction method, UV-vis-near-IR spectra of solutions, solid-state diffuse reflectance spectroscopies, and electrical conductivity measurements. The structures exhibit one-dimensional metal-dimer chains of M(2)(dtp)(4) with moderate interdimer contact. These complexes are semiconducting or insulating, which is consistent with the fully filled d(z)2 band of M(II)(d(8)). Interdimer metal-metal distances were 3.644(2) Angstroms in Ni(2)(dtp)(4) and 3.428(2) Angstroms in Pd(2)(dtp)(4), each of which is marginally longer than twice the van der Waals radius of the metal. Interdimer charge-transfer transitions were nevertheless observed in diffuse reflectance spectra. The origin of this transition is considered to be due to an overlap of two adjacent d(sigma) orbitals, which spread out more than the d(z)2 orbital because of the antibonding d(sigma) character of the M(d(z)2)-M(d(z)2). The Ni(2)(dtp)(4) exhibited an interdimer charge-transfer band at a relatively low energy region, which is derived from the Coulomb repulsion of the 3d(sigma) orbital of Ni.

Journal Article↗
PubMed2006

Molecular cloning and characterization of an enzyme hydrolyzing p-nitrophenyl alpha-D-glucoside from Bacillus stearothermophilus SA0301.

Bacillus stearothermophilus SA0301 produces an extracellular oligo-1,6-glucosidase (bsO16G) that also hydrolyzes p-nitrophenyl alpha-D-glucoside (Tonozuka et al., J. Appl. Glycosci., 45, 397-400 (1998)). We cloned a gene for an enzyme hydrolyzing p-nitrophenyl alpha-D-glucoside, which was different from the one mentioned above, from B. stearothermophilus SA0301. The k(0)/K(m) values of bsO16G for isomaltotriose and isomaltose were 13.2 and 1.39 s(-1).mM(-1) respectively, while the newly cloned enzyme did not hydrolyze isomaltotriose, and the k(0)/K(m) value for isomaltose was 0.81 s(-1).mM(-1). The primary structure of the cloned enzyme more closely resembled those of trehalose-6-phosphate hydrolases than those of oligo-1,6-glucosidases, and the cloned enzyme hydrolyzed trehalose 6-phosphate. An open reading frame encoding a protein homologous to the trehalose-specific IIBC component of the phopshotransferase system was also found upstream of the gene for this enzyme.

Amino Acid Sequence↗
PubMed2005

Synthesis and characterization of stable polymer-coated C8 stationary phase with high durability under extreme pH conditions for high-performance liquid chromatography.

A highly chemically stable polymer-coated silica-based C8 stationary phase was developed by combining modification with octyl groups and a polymer coating technology. The stationary phase was prepared by the following procedure: (1) introduction of octyl groups to the silica surface; (2) coating the C8 silica with a silicone polymer. 29Si solid-state NMR spectra indicated that a silicone polymer reacted not only with residual silanol groups on the silica surface, but with those generated from silanes used for the introduction of octyl groups. Column durability was evaluated with an acidic mobile phase (60 degrees C, pH 1) and a basic mobile phase (50 degrees C, pH 10) in accelerated damaging conditions. The C8 phase showed a high durability under both conditions.

Chromatography, High Pressure Liquid↗
PubMed2005

Genome-wide screening of aluminum tolerance in Saccharomyces cerevisiae.

Genome-wide screening has identified 37 Al-tolerance genes in Saccharomyces cerevisiae. These genes can be roughly categorised into three groups on the basis of function, i.e., genes related to vesicle transport processes, signal transduction pathways, and protein mannosylation. The largest group is composed of genes related to vesicle transport processes; severe Al sensitivity was found in yeast strains lacking these genes. The retrograde transport of endosome-derived vesicles back to the Golgi apparatus is an important factor in determining the Al tolerance of the vesicle transport system. The PKC1-MAPK cascade signalling pathway is important in the Al tolerance of signal transduction. The lack of the gene implicated in this process leads to weakened cell wall architecture, rendering the yeast Al-sensitive. Alternatively, Al might attack the cell wall and/or plasma membrane, and, as signalling is prevented in cells devoid of the genes related to signalling processes, the cells may be unable to alleviate the damage. The genes for protein mannosylation are also associated with Al tolerance, demonstrating the importance of cell wall architecture. These genes are involved in cell integrity processes.

Aluminum↗
PubMed2005

Secretion of an aluminum chelator, 2-isopropylmalic acid, by the budding yeast, Saccharomyces cerevisiae.

An aluminum(III)-binding substance (ABS), that solubilizes Al(III) at neutral pH, was found to be secreted by Saccharomyces cerevisiae. A combination of anion exchange chromatography and preparative high performance liquid chromatography using an octadecylsilane (ODS) column separated ABS from the medium. The structure determination of ABS was performed using 1H and 13C NMR spectroscopy and heteronuclear multiple-bond correlation (HMBC) spectroscopy, and ABS was identified to be 2-isopropylmalic acid (2-iPMA). The structure was further confirmed using high resolution electrospray ionization mass spectrometry. Solubilization of otherwise sparingly soluble Al(III) by 2-iPMA at neutral pH indicated the binding of the compound with Al(III). This is supported by 27Al NMR spectrometry for a solution containing 10 mM Al(III) and 20 mM 2-iPMA at pH 6.6, where four Al(III) species were evident. Although the function of this compound is unclear, it might play a key role in Al detoxification.

Aluminum↗
PubMed2005

Type 1 and type 2 human PrPSc have different aggregation sizes in methionine homozygotes with sporadic, iatrogenic and variant Creutzfeldt-Jakob disease.

In Creutzfeldt-Jakob disease (CJD), the type (type 1 or 2) of abnormal isoform of the prion protein (PrP(Sc)) in the brain and the genotype at codon 129 of the PrP gene are major determinants of clinicopathological phenotype. Little is known about the difference in biochemical properties between the two types of PrP(Sc), except for the different proteinase K cleavage sites. To investigate the size of aggregates formed by PrP(Sc) types 1 and 2, brain homogenates from various cases of CJD with the same genotype (homozygous for methionine at codon 129) were passed through filters with a mean pore size of 72+/-4 nm. Type 2 PrP(Sc) was efficiently removed from the filtrates by the filters, in contrast to type 1. Even type 2 PrP(Sc) from a patient without amyloid plaques was removed more efficiently than type 1 from patients with amyloid plaques. These results indicate that type 2 PrP(Sc) has a larger aggregation size than type 1, irrespective of the existence of amyloid plaques.

Blotting, Western↗
PubMed2005

Increased reactive oxygen species and anti-oxidative response in mitochondrial cardiomyopathy.

A 60-year-old woman was admitted for treatment of congestive heart failure. She had been diagnosed with diabetes mellitus when she was 23 years old, and she began to go deaf when she was 34 years old. She showed symptoms of heart failure at age 51 and was diagnosed with hypertrophic cardiomyopathy. Echocardiography showed progressive diffuse hypokinetic motion of the left ventricle and the left ventricular hypertrophy had gradually regressed. A mitochondrial transition mutation, A3243G, was detected in her peripheral leukocytes (9%) and in those of her 27-year-old son, who also has diabetes and deafness. Electron microscopy of an endomyocardial biopsy specimen showed proliferation and swelling of the mitochondria, and significant generation of reactive oxygen species (ROS), as well as marked induction of heme oxygenase-1, which is an adaptive enzyme to oxidative damage, were also observed in the myocardial tissue. These observations were more prominent than in other patients with heart failure of different etiology, which suggests that the increased ROS generation and anti-oxidative response were involved in the development of the mitochondrial cardiomyopathy.

Cardiomyopathy, Hypertrophic↗
PubMed2004

Novel PCR-mediated mutagenesis employing DNA containing a natural abasic site as a template and translesional Taq DNA polymerase.

We describe a novel method of PCR-mediated mutagenesis employing DNA containing a natural abasic site and translesional Taq DNA polymerase. This method incorporated an adenine (80.8%) or guanine (7.7%) residue or led to a base deletion mutation (11.2%) opposite the abasic site. We conclude that the combination of DNA containing an abasic site and translesional Taq DNA polymerase is an easy and useful technique for PCR-mediated mutagenesis, having advantages different from those of conventional error-prone PCR.

DNA↗
PubMed2004

Proprioception and performance after anterior cruciate ligament rupture.

The aim of this study was to investigate the characteristics of proprioception in patients with an anaterior-cruciate-ligament (ACL)-injured knee and to determine whether there is a correlation between proprioception and performance. We studied 32 patients with unilateral isolated ACL ruptures. Proprioception of the knee was evaluated by examining the joint position sense. Functional performance was evaluated with the one-leg hop (OLH) and one-leg vertical jump (OLV) tests. The mean error angle of the joint position sense was 3.6+/-1.5 degrees on the intact side and 5.2+/-1.9 degrees on the injured side. The joint position sense was thus clearly reduced on the injured side (p<0.05). The distance of jumping in the OLH test and the height of jumping in the OLV test was also clearly reduced on the injured side compared with that on the intact side (p<0.01) both with and without visual control. Moreover, we found a significant correlation between proprioception and performance in the ACL-injured knees, and this correlation was more distinct with visual deprivation. In conclusion, decreased proprioception in patients with ACL deficiency reduced their functional ability.

Adolescent↗
PubMed2004

A novel treatment of hypermobile lateral meniscus with monopolar radiofrequency energy.

Orthopedic treatment with radiofrequency energy (RFE) was first used in shoulder surgery, and its effectiveness has been reported. The purpose of RFE treatment of soft tissue is to induce qualitative changes in collagen and obtain stability. Hypermobile lateral meniscus (HLM) is characterized by abnormal mobility resulting from rupture or defects of the popliteomeniscal fasciculi, but no satisfactory treatment has been reported. We followed up patients with HLM who underwent monopolar RFE treatment and confirmed its short-term effects by magnetic resonance imaging and second-look arthroscopy.

Adolescent↗
PubMed2004

Analyses of PCR products using DNA templates containing a consecutive deoxyinosine sequence.

We determined nucleotide incorporation specificity of four thermostable DNA polymerases opposite deoxyinosine in order to evaluate the mutagenic effect of the presence of a consecutive deoxyinosine sequence during PCR amplification. Deoxycytosine was the only incorporated nucleotide opposite deoxyinosine during PCR amplification, irrespective of origin of DNA polymerase.

Base Pairing↗