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Biomedical subjects

M Yamamoto

Publications and source records attributed to M Yamamoto.

At least 109 records · Page 6Linked to original sources
PubMed2003

The organization of genes tightly linked to the Ha locus in Aegilops tauschii, the D-genome donor to wheat.

The grain hardness locus, Ha, is located at the distal end of the short arm of chromosome 5D in wheat. Three polypeptides, puroindoline-a, puroindoline-b, and grain softness protein (GSP-1), have been identified as components of friabilin, a biochemical marker for grain softness, and the genes for these polypeptides are known to be tightly linked to the Ha locus. However, this region of the chromosome 5D has not been well characterized and the physical distance between the markers is not known. Separate lambda clones containing the puroindoline-a gene and the puroindoline-b gene have been isolated from an Aegilops tauschii (the donor of the D genome to wheat) genomic lambda library and investigated. Considerable variation appears to exist in the organization of the region upstream of the gene for puroindoline-b among species closely related to wheat. Using in situ hybridization the genes for puroindoline-a, -b, and GSP-1 were demonstrated to be physically located at the tip of the short arm of chromosome 5 of A. tauschii. Four overlapping clones were isolated from a large-insert BAC library constructed from A. tauschii and of these one contained genes for all of puroindoline-a, puroindoline-b, and GSP-1. The gene for puroindoline-a is located between the other two genes at a distance no greater than approximately 30 kb from either gene. The BAC clone containing all three known genes was used to screen a cDNA library constructed from hexaploid wheat and cDNAs that could encode novel polypeptides were isolated.

Chromosomes, Plant↗
PubMed2003

The sugary-type isoamylase gene from rice and Aegilops tauschii: characterization and comparison with maize and arabidopsis.

Genes for an isoamylase-like debranching enzyme have been isolated from rice and Aegilops tauschii, the donor of the D genome to wheat. The structures of the genes are very similar to each other and to the maize SU1 isoamylase gene and consist of 18 exons spread over approximately 7.5 kb. Southern analysis and fluorescent in situ hybridization showed the Ae. tauschii gene to be located in the proximal region of the short arm of chromosome 7D, thus showing synteny with the localization of the rice isoamylase gene on rice chromosome 8. Analysis of the expression pattern of wheat sugary isoamylase genes indicates that they are strongly expressed in the developing endosperm 6 days after flowering. Three distinct Sugary-type cDNA sequences were isolated from the wheat endosperm that are likely to correspond to the products of the three genomes. The deduced amino acid sequence of rice and wheat Sugary-type isoamylase is compared with other sequences available in the database and the results demonstrate that there are three types of isoamylase sequences in plants: those containing 18 exons (the Sugary-type isoamylase gene), those containing 21 exons, and those containing only 1 exon. It is possible that different combinations of isoamylase genes are expressed in different tissues.

Amino Acid Sequence↗
PubMed2003

Extended chromatin and DNA fibers from active plant nuclei for high-resolution FISH.

The conventional protocol for isolation of cell wall free nuclei for release of DNA fibers for plants involves mechanical removal of the cell wall and separation of debris by sieve filtration. The mechanical grinding pressure applied during the process leaves only the more tolerant G(1) nuclei intact, and all other states of active nuclei that may be present in the target tissues (e.g., leaf) are simply crushed/disrupted during the isolation process. Here we describe an alternative enzymatic protocol for isolation of nuclei from root tip tissue. Cell wall free nuclei at a given stage of cell cycle, free of any cell debris, could be realized in suspension that are fit for preparation of extended fibers suitable for fiber FISH applications. The protocol utilizes selective harvest of active nuclei from root tip tissue in liquid suspension under the influence of cell wall-degrading enzymes, and provides opportunities to target cell cycle-specific nuclei from interphase through division phase for the release of extended DNA fibers. Availability of cell cycle-specific fibers may have added value in transcriptional analysis, DNA:RNA hybridization, visualization of DNA replication and replication forks, and improved FISH efficiency.

Cell Cycle↗
PubMed2003

Does decreased T1 signal intensity in the retrodiscal tissue of the temporomandibular joint reflect increased density of collagen fibres?

OBJECTIVE: To evaluate whether decreased signal intensity on T(1) weighted MR images of the retrodiscal tissue of the temporomandibular joint (TMJ) reflects increased density of collagen fibres. METHODS: Corrected sagittal T(1) weighted MR images of six TMJs from six fresh cadavers (three males and three females; age range 76-87 years, mean 80.8 years) were obtained. Following MRI, slices of tissue samples were taken from the cadavers that exactly matched the planes of the MR image. These samples were fixed, decalcified and stained (haematoxylin-eosin stain, Elastica van Gieson's stain) for light microscopy. The samples were evaluated for density of collagen fibres according to Hall et al (1984) and for vascularity, arterial wall thickness, fat content and elastin. In these sagittal samples, the retrodiscal tissue was divided anteroposteriorly and vertically into six areas and each area was classified by histological parameters. The MR images were similarly divided into six areas. Areas with reduced signal intensity were classified as the low signal group and those with no reduced signals were classified as the control group. RESULTS: Collagen density assessed histologically differed between the low signal intensity group and the control group, and loose collage density on the histological samples was observed significantly more often in the low signal group (Fisher's exact test, P=0.03). There were no statistically significant differences in the other categories between the two groups. CONCLUSION: The results suggest that reduced T1 signals of retrodiscal tissue do not necessarily reflect a dense distribution of collagen fibres.

Aged↗
PubMed2003

[How much can off-pump coronary artery bypass grafting be performed for complete revascularization using only in situ arterial conduits?].

With the rapid advance of percutaneous catheter intervention, the direction taken by surgeons is not only to make coronary artery bypass grafting (CABG) less invasive but also to obtain better long-term results by using more arterial conduits. However, off-pump CABG (OPCAB) with only in situ arterial conduits such as the left and right internal thoracic arteries (ITAs) and the right gastroepiploic artery (RGEA) is technically demanding for the surgeon. The purpose of this study was to demonstrate the feasibility and safety of this technique. From January 2002 to December 2002, 57 patients underwent isolated CABG without cardiopulmonary bypass, excluding minimally invasive direct coronary artery bypass (MIDCAB) cases. There were 44 men and 13 women with a mean age of 64.1 years. Most of the patients (95%) underwent postoperative angiography within 1 month after surgery. The mean number of anastomoses was 3.8 +/- 1.4 (range 2-8). One patient suffered from mediastinitis and another from stroke. All patients were discharged from the hospital. Fifty patients (88%) received only in situ grafts for complete revascularization. Forty-one patients received bilateral ITAs and 27 received bilateral ITAs and RGEA. The mean number of anastomoses using bilateral ITAs and RGEA was 4.5 +/- 1.2 (range 3-8). The patency rate was 98%. Complete arterial revascularization with only in situ arterial conduits was associated with minimal operative risk and a high early graft patency rate, even in the off-pump situation. These results indicate that complete revascularization can be achieved in OPCAB with the exclusive use of in situ arterial conduits in patients with diffuse coronary arterial disease.

Adult↗
PubMed2002

Transverse sound in liquid-3He-aerogel system.

Transverse sound in normal liquid 3He in aerogel is studied on the basis of the Landau transport equation taking into account the simultaneous oscillation of the aerogel. We show that the nature of transverse sound is strongly modified if aerogel is immersed in the liquid. Scattering of 3He quasiparticles by the aerogel molecules causes friction between the liquid and the aerogel, giving rise to coupled motion of the two systems. There exists a low-attenuation transverse sound mode in this coupled system. The high-temperature behavior of its attenuation alpha is given by alpha proportional, variant const+T-2, which is in contrast to alpha proportional, variant T in pure liquid 3He in the hydrodynamic regime.

Journal Article↗
PubMed2002

The structural organisation of the gene encoding class II starch synthase of wheat and barley and the evolution of the genes encoding starch synthases in plants.

Wheat and barley contain at least four classes of starch synthases in the endosperm, granule bound starch synthase I (GBSSI) and starch synthases I, II and III (SSI, SSII, SSIII). In this work, SSII in barley is shown to be associated with the starch granule by using antibodies. A cDNA from barley encoding SSII and the genes for SSII from barley and Aegilops tauschii ( A. tauschii, the D genome donor to wheat) are characterised. Fluorescent in situ hybridisation (FISH) and PCR were used to localise the wheat SSII gene to the short arm of chromosome 7, showing synteny with the location of the rice SSII gene to the short arm of chromosome 6. Comparison of the genes encoding SSII of A. tauschii, barley and Arabidopsis showed a conserved exon-intron structure although the size of the introns varied considerably. Extending such comparison between the genes encoding starch synthases (GBSSI, SSI, SSII and SSIII) from A. tauschii and Arabidopsis showed that the exon-intron structures are essentially conserved. Separate and distinct genes for the individual starch synthases therefore existed before the separation of monocotyledons and dicotyledons.

Base Sequence↗
PubMed2002

Biodegradation of triazine herbicides on polyvinylalcohol gel plates by the soil yeast Lipomyces starkeyi.

The soil yeast Lipomyces starkeyi was tested for its ability to degrade triazine herbicides. Polyvinylalcohol (PVA) was employed as a solid medium in culture plates instead of agar. The cell sizes of the control (without nitrogen source) on the PVA gel plate were much smaller than those on the agar gel plate. The difference between the diameters of the sample and control colonies on the PVA gel plate were almost twice those of the colonies on the agar gel plate (1.9 and 1.0 mm, respectively). Thus, the PVA gel plate is much better than the agar plate for evaluating the degree of utilization of a sole nitrogen source. The yeast grew well (more than 4 mm in diameter) with 1,3,5-triazine or cyanuric acid as nitrogen source. In addition, melamine and thiocyanuric acid inhibited growth of the yeast, and the sizes of colonies were smaller than those of the control. All triazine herbicides tested (simazine, atrazine, cyanazine, ametryn, and prometryn) could be degraded and assimilated by L. starkeyi.

Agar↗
PubMed2002

The effects of methyl mercaptan on epithelial cell growth and proliferation.

AIM: Previous studies have demonstrated that methyl mercaptan (CH3SH), one of the main causes of oral malodour, might contribute to the initiation and progression of periodontal disease. These studies suggested that CH3SH may affect the epithelial cells of the gingival crevice, which form a barrier to the penetration of microbial substances. In this study, the effects of CH3SH on the epithelial cells and gingival fibroblasts were investigated. METHOD: Human oral epithelial carcinoma cell line (KB), human oral squamous cell carcinoma cell line (HSC-2), and human gingival fibroblasts (HGF) derived from healthy gingiva were used in this study. These cells were cultured in conditions of 5% CO2/95% air with or without CH3SH (10 ng/ml or 50 ng/ml) for 5 days. Cell numbers, proliferation and cytotoxicity were evaluated. RESULTS: CH3SH inhibited epithelial cell growth and proliferation at the concentration of 50 ng/ml, and a cytotoxic effect of CH3SH was also noted. On the other hand, HGF cells were not affected by 50 ng/ml CH3SH. CONCLUSION: High concentrations of CH3SH such as 50 ng/ml have an inhibitory effect on the growth and proliferation of epithelial cells, but not on those of fibroblasts.

Analysis of Variance↗
PubMed2002

Hypovitaminosis D and hyperparathyroidism in physically inactive elderly Japanese living in nursing homes: relationship with age, sunlight exposure and activities of daily living.

BACKGROUND AND AIMS: The purposes of this study were to investigate the prevalences of hypovitaminosis D and hyperparathyroidism in physically inactive elderly people living in Japanese nursing homes and determine any correlations with demographic, environmental and/or life-style factors. METHODS: We targeted 220 elderly people living in nursing homes for the physically disabled in Japan. Of these, 133 (women, 113; men, 20) subjects who agreed and met our inclusion criteria were studied. The average age of the subjects was 84.6 years (SD 8.2). Serum 25-hydroxyvitamin D3 (25[OH]D3), intact parathyroid hormone (intact PTH), creatinine, and albumin concentrations were measured in each subject. Total hours of sunshine during the previous 5 weeks, activities of daily living (ADL) levels, and dietary vitamin D intake were also measured. ADL levels were evaluated using the Physical Self-Maintenance Scale (5-point scale). The examinations were performed between October and December, 1999. RESULTS: The average concentrations of serum 25(OH)D3 and intact PTH were 29.9 nmol/L (SD 13.1) and 5.04 pmol/L (SD 2.27), respectively. The prevalences of hypovitaminosis D (25[OH]D3<30 nmol/L) and hyperparathyroidism (intact PTH>6.90 pmol/L) were 77/133 (57.9%) and 21/133 (15.8%), respectively. Serum 25(OH)D3 concentrations were positively associated with hours of sunshine (R2=0.371, p<0.001) and serum albumin concentrations (R2=0.086, p<0.001), but not with age (p=0.075) or total ADL score (p=0.527). A negative association between serum intact PTH and 25(OH)D3 levels was found in subjects who were 80 years or older (p<0.001) but not in subjects under the age of 80 years. CONCLUSIONS: Hypovitaminosis D and hyperparathyroidism are commonly seen in elderly Japanese with low ADL levels. Hypovitaminosis D seems to adversely affect PTH levels, especially in the very elderly.

Activities of Daily Living↗
PubMed2002

An anti-rheumatic agent T-614 inhibits NF-kappaB activation in LPS- and TNF-alpha-stimulated THP-1 cells without interfering with IkappaBalpha degradation.

OBJECTIVE: Compound T-614, a member of the methanesulfoanilide class of anti-inflammatory agents, shows potent anti-arthritic activity in animal models of rheumatoid arthritis. The aim of the present investigation was to characterize the anti-arthritic activity of T-614 in terms of regulation of the nuclear transcription factor NF-kappaB, which is associated with expression of many immune and inflammatory genes. MATERIALS AND METHODS: THP-1 cells (human monocytic leukemia cell line) were used throughout this in vitro study, and lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-alpha were employed for activation of the cells. Cytokine production was assayed by enzyme-linked immunosorbent assay (ELISA). The mRNA levels were determined by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay. Assessment of the NF-kappaB DNA binding activity was performed by an electrophoretic mobility shift assay (EMSA) using a digoxigenin (DIG)-labeled double-stranded oligonucleotide containing kappaB-binding site. Degradation kinetics of the cytosolic NF-kappaB inhibitor a (IkappaBalpha) were studied by Western blot analysis. RESULTS: T-614 inhibited LPS-stimulated production of TNF-alpha, interleukin (IL)-6, and IL-8 in a concentration-dependent manner with decreasing mRNA levels (IL-6 and IL-8). EMSA study showed that T-614 prevented TNF-alpha as well as LPS-stimulated activation of NF-kappaB, and Western blot analysis proved that T-614 did not affect degradation of IkappaBalpha protein. CONCLUSIONS: These results suggest that the inhibitory effect of T-614 on the production of TNF-alpha, IL-6 and IL-8 in LPS-stimulated THP-1 cells may involve transcriptional regulation through suppression of NF-kappaB activation without interfering with IkappaBalpha degradation.

Antirheumatic Agents↗
PubMed2002

Chemical characterization of cytoplasmic lipid droplets in the pheromone-producing cells of the silkmoth, Bombyx mori.

Accumulation of lipid droplets within the cytoplasm is a common feature of the pheromone gland cells of many lepidopteran species. The cytoplasmic lipid droplets in the pheromone-producing cells of the silkmoth, Bombyx mori, were effectively extracted by dipping the trimmed glands in acetone for 10 min. In order to analyze the components originating from the lipid droplets, we separated the acetone extracts prepared before and after adult eclosion using HPLC, and specified the peaks showing a similar pattern of stage-dependence to that in the morphological change of the lipid droplets previously reported by Fónagy et al. (Arthropod Struct. Dev. 30 (2001) 113). Finally, we specified the peaks #1-5 and #1a-4a separated by reversed-phase HPLC as lipid droplet contents. Structure elucidation using FAB-MS and MS-MS analyses confirmed that they were triacylglycerols (TGs), and 12 species of TGs were identified as lipid droplet contents. Fatty acyl groups contained in these TGs were limited to five unsaturated C16 and C18 fatty acyl groups (delta 11-hexadecenoate, delta 10,12-hexadecadienoate, delta 9-octadecenoate, delta 9,12-ocatadecadienoate, and delta 9,12,15-ocatadecatrienoate), including the pheromone precursor delta 10,12-hexadecadienoate as a major component. Digestion with porcine pancreatic lipase confirmed that three major TGs eluted in the peaks #3-5 all contained C18 fatty acyl groups at the sn-2 position, indicating that the pheromone precursor is sequestered preferentially at the sn-1 and/or sn-3 position. Present results combined with the fact that the morphological change of the lipid droplets is under the control of PBAN indicate that the role of the cytoplasmic lipid droplets in the pheromone-producing cells is to store the pheromone precursor in the form of TGs and to provide it for pheromone production in response to the external signal of PBAN.

Animals↗
PubMed2002

Bending property and phase transformation of Ti-Ni-Cu alloy dental castings for orthodontic application.

Bending property of Ti-Ni-Cu alloy castings was investigated in a three-point bending test for orthodontic application in relation to the phase transformation. The compositions of the alloys were Ti-50.8Ni and Ti-40.8Ni-10.0Cu (mol %), and four cross-sectional shapes of the specimens were selected. Heat treatment was performed at 713, 753 or 793 K for 1.8 ks. The bending load changed by the cross-sectional size and shape mainly because of the difference in the moment of inertia of area, but the load-deflection relation did not differ proportionally in the unloading process. The difference between the load values in the loading and the unloading processes was relatively small for Ti-Ni-Cu alloy. With respect to the residual deflection, there was no significant difference between Ti-Ni and Ti-Ni-Cu alloys with the same treatment condition. The load values in the loading and the unloading processes decreased by each heat treatment for Ti-Ni alloy; however, the decrease in the load values for Ti-Ni-Cu alloy was not distinct. It is proved that Ti-Ni-Cu alloy castings produce effective orthodontic force as well as stable low residual deflection, which is likely to be caused by the high and sharp thermal peaks during phase transformation.

Journal Article↗
PubMed2002

Acoustic characteristics of sounds from temporomandibular joints with and without effusion: an MRI study.

Joint effusion has been associated with temporomandibular joint (TMJ) pain but can only be diagnosed by magnetic resonance imaging (MRI). For screening of patients with suspected effusion a simple and less expensive method would be desirable. We recorded joint sounds during jaw opening and closing movement from 34 TMJs with internal derangement (ID). Seventeen joints had joint effusion seen on MRI. Spectrograms of the sounds were displayed as waterfall plots showing profiles of the consecutive Hamming windows. If the profiles were similar, as judged by initial evaluation, the displayed pattern was classified as stable. If some profiles were distinctly deviating in their pattern, this was classified as unstable. Joints with effusion showed unstable sound pattern more often than joints without effusion (P < 0.001). It was concluded that TMJ sound analyses have a potential to identify joints with effusion based on their unstable sound pattern.

Adult↗
PubMed2002

The renal structure in an Asian elephant (Elephas maximus).

The renal structure of a female Asian elephant (Elephas maximus) was observed in both macroscopic and light microscopic levels. The left kidney was elongated-ellipse in shape, whereas the right appeared round. The left kidney was 31 cm in cranio-caudal length, 21 cm in medio-lateral length, and 2950 g in weight. The right kidney was 34 cm in cranio-caudal length, 22 cm in medio-lateral length, and 3250 g in weight. The external appearance showed the six separated renal lobes in both sides of the kidney. The four pairs of the lobes were fused in the deepest region in both sides of kidney, so we considered it as an incompletely lobated kidney in this species. We observed the proximal and distal urinary tubules in histological sections. Many renal corpuscles consisted of the glomerulus and Bowman's capsule. Many mesangial cells and some podocytes were confirmed in each glomerulus; however, Bowman's capsules were larger than those in other mammalian species.

Animals↗
PubMed2002

Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles.

The masticatory muscles and their related structures of the skull were observed in the Indian gavial (Gavialis gangeticus), the false gavial (Tomistoma schlegelii), and the African slender-snouted crocodile (Mecistops cataphractus) to detail some morphological differences in comparison with the other crocodile species, and to compare and elucidate the functional strategy of themasticatory apparatus in these long-snouted species. The Musculus pterygoideus posterior was relatively smaller in the three species compared with many short-snouted crocodiles. It suggests that the masticatory power in fish-eating long-snouted species is not so high as in the short-snouted crocodiles, while the masticatory muscles were morphologically different among the three long-snouted species as follows. The M. pterygoideus posterior of the false gavial was extended in the lateral side of the lower jaw unlike the Indian gavial. The M. pseudotemporalis and the Fenestra supratemporalis were largely developed in the Indian gavial, however we suggest that the other two species possess the weak bundles in this muscle. The false gavial and the African slender-snouted crocodile have the pterygoid bone well-developed extending dorso-ventrally and it is suggested that the M. adductor mandibulae posterior attached to the pterygoid bone may be much larger than the Indian gavial. These data morphologically clarify the masticatory mechanism in the long-snouted crocodiles different from the short-snouted species, and demonstrate that the evolutional strategy to share the functional role in the masticatory muscles have been differently established between the Indian gavial and the other two species. We also obtained the morphological data in the fossil skull of the Machikane crocodile (Toyotamaphymeia machikanense) and concluded from the fossil characters that the considerable developments of the M.pterygoideus posterior and the M.pseudotemporalis in this species had not morphologically been consistent with both the Indian and false gavials.

Alligators and Crocodiles↗
PubMed2002

Development of antigen induced colitis in SCID mice reconstituted with spleen derived memory type CD4(+) CD45RB(+) T cells.

BACKGROUND AND AIMS: Enteric bacterial and/or food antigens may be crucial in the development of colitis but little is known of the exact mechanism of antigen specific reactions in this condition. The aim of this study was to determine whether systemically primed antigen specific CD4(+) T cells containing both CD45RB(high) and CD45RB(low) populations participate as a pathogenic subset that in turn leads to inflammatory reactions selectively in the large intestine. METHODS: SCID mice were reconstituted with splenic CD4(+) CD45RB(+) T cells or CD4(+) CD45RB(low) T cells isolated from donor mice systemically primed with ovalbumin (OVA) plus CFA. The reconstituted mice were then fed OVA for several weeks. RESULTS: Reconstitution of SCID mice with OVA primed splenic CD4(+) T cells, containing populations of CD45RB(high) and CD45RB(low), resulted in the development of colitis by 4-5 weeks following repeated administration of oral OVA. Histopathological study revealed thickened wall, inflammatory cell infiltration, crypt elongation, and loss of goblet cells in the large intestine. The CD4(+) CD45RB(low) population of cells extracted from the affected large intestine secreted high levels of interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) at the protein and mRNA levels. Administration of neutralising antibodies to TNF-alpha, but not to IFN-gamma, prevented the development of colitis. Furthermore, adoptive transfer with OVA primed splenic CD4(+) CD45RB(low) T cells evoked severe colitis. CONCLUSIONS: These results demonstrate that systemically primed activated/memory CD4(+) CD45RB(low) T cells can mediate the development of specific antigen induced colitis in SCID mice, and also that TNF-alpha is critical in the induction of this type of colitis. Our results contrast with those from studies in some colitis models in which CD45RB(low) T cells appeared to prevent colitis through secretion of immunosuppressive cytokines.

Adoptive Transfer↗