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Biomedical subjects

T Sugiyama

Publications and source records attributed to T Sugiyama.

At least 55 records · Page 3Linked to original sources
PubMed2001

Measurement of plasma brain natriuretic peptide level as a guide for cardiac overload.

OBJECTIVES: We examined whether measurement of the plasma BNP concentrations might be useful for the early diagnosis of the existence and severity of disease in patients with heart disease in daily clinical practice. METHODS AND RESULTS: The plasma BNP and ANP concentrations in 415 patients with heart disease and hypertension and 65 control subjects were measured. Patients with heart disease had higher plasma BNP and ANP concentrations than did those with hypertension or control subjects. Among the etiology of cardiac diseases, specifically dilated cardiomyopathy and hypertrophic cardiomyopathy, was associated with the highest plasma BNP concentrations, whereas dilated cardiomyopathy was associated with the highest plasma ANP concentrations. Plasma BNP concentrations showed an increase as the severity of the heart disease, as graded according to the NYHA classification of cardiac function, increased. In both patients with heart disease and hypertension, the plasma BNP values were higher in those who had abnormalities in their echocardiogram and electrocardiogram as compared to those without any abnormalities. The plasma BNP levels also showed a significant correlation with left ventricular wall thickness and left ventricular mass. On the other hand, the plasma ANP levels showed significant correlations with left ventricular dimension. Receiver operative characteristic analysis revealed that plasma BNP levels showed substantially high sensitivity and specificity to detect the existence of heart diseases. CONCLUSION: Measurements of the plasma BNP concentrations is useful to detect the existence of the diseases, and abnormalities of left ventricular function and hypertrophy in patients with heart disease in daily clinical practice.

Atrial Natriuretic Factor↗
PubMed2001

Capping the cost of compliance with the Kyoto Protocol and recycling revenues into land-use projects.

There is the concern among some countries that compliance costs with commitments under the Kyoto Protocol may be unacceptably high. There is also the concern that technical difficulties with the inclusion of land use, land-use change, and forestry activities in non-Annex I countries might lead to an effective exclusion of such activities from consideration under the Protocol. This paper is proposing a mechanism that addresses both these concerns. In essence, it is suggested that parties should be able to purchase fixed-price offset certificates if they feel they cannot achieve compliance through other means alone, such as by improved energy efficiency, increased use of renewable energy, or use of the flexible mechanisms in the Kyoto Protocol. These offset certificates would act as a price cap for the cost of compliance for any party to the Protocol. Revenues from purchase of the offset certificates would be directed to forest-based activities in non-Annex I countries such as forest protection that may carry multiple benefits including enhancing net carbon sequestration.

Energy-Generating Resources↗
PubMed2001

High-performance liquid chromatographic assay of zonisamide in human plasma using a non-porous silica column.

A new method for measuring zonisamide (ZNS) in plasma by high-performance liquid chromatography was developed by using a 2-microm reversed-phase non-porous silica column. ZNS in plasma was first purified with a column extraction technique and injected onto the non-porous silica column. Calibration curve was linear over the concentration range of 1-80 microg/ml in plasma. The recoveries of ZNS added to plasma were more than 95.4% with the coefficient of variation less than 9.0%. We developed a rapid routine method using the non-porous silica column that was accurate and improved solvent consumption in the measurement of ZNS.

Anticonvulsants↗
PubMed2001

Inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of doxorubicin.

Theanine, a major amino acid existing in green tea, enhanced the antitumor activity of doxorubicin (DOX) due to inhibition of DOX efflux from tumor cells. In order to clarify the mechanism, we have investigated the contribution of glutamate transporters to the action of theanine, because theanine is a glutamate analogue. In M5076 ovarian sarcoma cells, glutamate transport inhibitors reduced the efflux of DOX, as well as theanine. Incidentally, theanine significantly inhibited the glutamate uptake by M5076 cells in a concentration-dependent manner similar to specific inhibitors. These results suggested that the inhibition of DOX efflux was induced by the inhibition of glutamate transport by theanine. In addition, RT-PCR and Western blot analysis revealed the expression of GLAST and GLT-1, astrocytic high-affinity glutamate transporters, in M5076 cells. Thus, theanine was shown to competitively inhibit the glutamate uptake by acting on these glutamate transporters. This action suggested the contribution of glutamate transporters to the inhibition of DOX efflux by theanine. We revealed the novel mechanism of enhancement of the antitumor efficacy of DOX via the inhibition of glutamate transporters by theanine.

2-Aminoadipic Acid↗
PubMed2001

cAMP and calcium ionophore induce outgrowth of neuronal processes in PC12 mutant cells in which nerve growth factor-induced outgrowth of neuronal processes is impaired.

During continuous culturing, PC12 cells are subject to spontaneous mutations. We obtained PC12m3 cells, clone cells in which outgrowth of neuronal processes (dendrites and axons) under the condition of nerve growth factor (NGF) treatment was highly stimulated by various inducers, such as cyclic adenosine monophosphate (cAMP), calcium ionophore, steroid and high osmolarity. The number of cells with neuronal processes in the presence of cAMP was approximately twenty-fold greater than PC12 parental cells and other PC12 mutant cells. In PC12m3 cells, NGF-induced outgrowth of neuronal processes was reduced by cytotoxic solanine, whereas the effect of NGF was unaffected by hyaluronic acid. In PC12m3 cells, various inducers of neurite outgrowth, such as cAMP, calcium ionophore and high osmolarity, activated mitogen activated protein (MAP) kinase, whereas solanine and hyaluronic acid did not cause any significant activation of MAP kinase. However, PC12m3 cells, in which NGF-induced outgrowth of neuronal processes were impaired, had strong NGF-induced MAP kinase activity as PC12 parental cells had. These findings suggest that cAMP, calcium influx and high osmolarity induce outgrowth of neuronal processes in PC12m3 cells through activation of the downstream target of MAP kinase or through a novel pathway independent of NGF activation.

Animals↗
PubMed2001

Identification of genes encoding adenylate isopentenyltransferase, a cytokinin biosynthesis enzyme, in Arabidopsis thaliana.

The initial step in the de novo biosynthesis of cytokinin in higher plants is the formation of isopentenyladenosine 5'-monophosphate (iPMP) from AMP and dimethylallylpyrophosphate (DMAPP), which is catalyzed by adenylate isopentenyltransferase (IPT). Although cytokinin is an essential hormone for growth and development, the nature of the enzyme for its biosynthesis in higher plants has not been identified. Herein, we describe the molecular cloning and biochemical identification of IPTs from Arabidopsis thaliana. Eight cDNAs encoding putative IPT, designated as AtIPT1 to AtIPT8, were picked up from A. thaliana. The Escherichia coli transformants expressing the recombinant proteins excreted cytokinin species into the culture medium except for that expressing AtIPT2 that is a putative tRNA IPT. A purified recombinant AtIPT1 catalyzed the formation of iPMP from DMAPP and AMP. These results indicate that the small multigene family contains both types of isopentenyltransferase, which could synthesize cytokinin and mature tRNA.

Alkyl and Aryl Transferases↗
PubMed2001

Rad54 protein stimulates heteroduplex DNA formation in the synaptic phase of DNA strand exchange via specific interactions with the presynaptic Rad51 nucleoprotein filament.

RAD54 is an important member of the RAD52 group of genes that carry out recombinational repair of DNA damage in the yeast Saccharomyces cerevisiae. Rad54 protein is a member of the Snf2/Swi2 protein family of DNA-dependent/stimulated ATPases, and its ATPase activity is crucial for Rad54 protein function. Rad54 protein and Rad54-K341R, a mutant protein defective in the Walker A box ATP-binding fold, were fused to glutathione-S-transferase (GST) and purified to near homogeneity. In vivo, GST-Rad54 protein carried out the functions required for methyl methanesulfonate sulfate (MMS), UV, and DSB repair. In vitro, GST-Rad54 protein exhibited dsDNA-specific ATPase activity. Rad54 protein stimulated Rad51/Rpa-mediated DNA strand exchange by specifically increasing the kinetics of joint molecule formation. This stimulation was accompanied by a concurrent increase in the formation of heteroduplex DNA. Our results suggest that Rad54 protein interacts specifically with established Rad51 nucleoprotein filaments before homology search on the duplex DNA and heteroduplex DNA formation. Rad54 protein did not stimulate DNA strand exchange by increasing presynaptic complex formation. We conclude that Rad54 protein acts during the synaptic phase of DNA strand exchange and after the formation of presynaptic Rad51 protein-ssDNA filaments.

Adenosine Triphosphatases↗
PubMed2001

The inhibitory action of sodium arsenite on lipopolysaccharide-induced nitric oxide production in RAW 267.4 macrophage cells: a role of Raf-1 in lipopolysaccharide signaling.

The effect of sodium arsenite (SA) on LPS-induced NO production in RAW 267.4 murine macrophage cells was studied. SA pretreatment of LPS-stimulated RAW cells resulted in a striking reduction in NO production. No significant difference in LPS binding was observed between RAW cells pretreated with SA and control untreated RAW cells, suggesting that SA might impair the intracellular signal pathway for NO production. SA inhibited LPS-induced NF-kappaB activation by preventing loss of IkappaB-alpha and -beta. Furthermore, SA blocked phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2), but not phosphorylation of p38 and c-Jun N-terminal kinase. SA treatment resulted in the disappearance of Raf-1, suggesting that it might cause the inhibition of the Erk1/2 mitogen-activated protein (MAP) kinase pathway. The SA-mediated loss of Raf-1 also abolished LPS-induced NF-kappaB activation as well as the Erk1/2 pathway. The dominant negative mutant of MAP kinase kinase 1 inhibited both NO production and NF-kappaB activation in LPS-stimulated RAW cells. Taken together, these results indicate that the inhibitory action of SA on NO production in LPS-stimulated macrophages might be due to abrogation of inducible NO synthase induction, and it might be closely related to inactivation of the NF-kappaB and Erk1/2 MAP kinase pathways through loss of Raf-1.

Animals↗
PubMed2001

Soluble CD14 mediates efflux of phospholipids from cells.

Soluble CD14 (sCD14), a 55-kDa glycoprotein found in plasma, has been shown to act as a shuttle for bacterial LPS and phospholipids, transporting LPS and phospholipid monomers from LPS aggregates or liposomes to high density lipoprotein particles. sCD14 has also been shown to mediate the transport of LPS and phosphatidylinositol into cells. Here we show that sCD14 mediates not only the influx but also the efflux of cellular phospholipids. Addition of sCD14 enhanced efflux of cellular phospholipids labeled with [(3)H]palmitic acid, [(3)H]oleic acid, or [(3)H]choline chloride from differentiated THP-1 monocytic cells. Efflux was dependent on the concentration of sCD14 added and was essentially complete in 30 min. The role of membrane-bound CD14 (mCD14) in lipid efflux was assessed using matched pairs of cell lines that express or fail to express this protein. While efflux was very dependent on mCD14 in U373 cells, it was not dependent on mCD14 in Chinese hamster ovary cells, suggesting a role for additional cellular proteins in determining the pathway of phospholipid efflux. A deletion mutant of sCD14 lacking the LPS binding site had less ability to efflux phospholipids than intact sCD14, suggesting that this site is needed for CD14 to serve in phospholipid transport. [(3)H]Palmitate-labeled lipids released by sCD14 were precipitated with anti-CD14 then analyzed by HPLC. Phosphatidylcholine was the dominant phospholipid exported and bound to sCD14. These results demonstrate that sCD14 mediates efflux of phospholipids from cells and suggest that sCD14 contributes to phospholipid transport in blood.

Acute-Phase Proteins↗
PubMed2001

HUNT: launch of a full-length cDNA database from the Helix Research Institute.

The Helix Research Institute (HRI) in Japan is releasing 4356 HUman Novel Transcripts and related information in the newly established HUNT database. The institute is a joint research project principally funded by the Japanese Ministry of International Trade and Industry, and the clones were sequenced in the governmental New Energy and Industrial Technology Development Organization (NEDO) Human cDNA Sequencing Project. The HUNT database contains an extensive amount of annotation from advanced analysis and represents an essential bioinformatics contribution towards understanding of the gene function. The HRI human cDNA clones were obtained from full-length enriched cDNA libraries constructed with the oligo-capping method and have resulted in novel full-length cDNA sequences. A large fraction has little similarity to any proteins of known function and to obtain clues about possible function we have developed original analysis procedures. Any putative function deduced here can be validated or refuted by complementary analysis results. The user can also extract information from specific categories like PROSITE patterns, PFAM domains, PSORT localization, transmembrane helices and clones with GENIUS structure assignments. The HUNT database can be accessed at http://www.hri.co.jp/HUNT.

Computational Biology↗
PubMed2001

Migration mechanism of bases and nucleosides in oil-in-water microemulsion capillary electrophoresis.

The electrophoretic behaviors of five bases and corresponding nucleosides in the oil in water (o/w) microemulsion capillary electrophoresis, microemulsion electrokinetic chromatography (MEEKC), were examined in comparison with those in normal capillary zone electrophoresis (CZE). The microemulsion systems were composed of heptane, sodium dodecyl sulfate (SDS), 1-butanol and 10 mM phosphate buffer (pH 7.0) or toluene, SDS, 1-butanol and 5 mM carbonate buffer (pH 10.0). CZE was carried out in the range of pH 9.7-10.9, and the dissociation constants, pKa, of the bases and nucleosides and the electrophoretic mobilities of the anionic forms were determined. The electrophoretic behaviors of the solutes in the microemulsion systems were analyzed from their pKa, the electrophoretic mobilities of the anions determined by CZE, and the distribution constants, K(D), of the neutral forms between the microemulsion droplets and the outer aqueous phase. The importance of adsorption mechanism in MEEKC system was suggested from the correlation between log K(D) and log P.

Acids↗
PubMed2001

Production of experimental autoimmune sialadenitis in mice immunized with homologous salivary gland extract and Klebsiella O3 lipopolysaccharide.

An experimental murine model for autoimmune sialadenitis was produced by repeated immunization of homologous salivary gland extract together with Klebsiella O3 lipopolysaccharides as an immunological adjuvant. The cell infiltration was observed in the salivary glands of mice immunized more than twice. Inflammatory cells consisting mainly of CD4+ T cells and CD8+ T cells accumulated at the perivascular regions. There was hyperplasia and enlargement of ductal epithelial cells in the secretory acinar units in salivary glands of repeatedly immunized mice. The repeated immunization developed delayed-type hypersensitivity and autoantibody production to the homologous salivary gland extract. The immunohistochemical analysis showed positive staining on the cuboidal cells in the intercalated ducts, and the columnar pseudostratified cells in the striated ducts. Organ-specific antigens with molecular weights ranging from 20 to 90 kDa were recognized by the sera from immunized mice. Therefore, it was suggested that the sialadenitis was produced by the autoimmune mechanism and might be a new experimental model for characterization of the pathogenesis of autoimmune sialadenitis.

Adjuvants, Immunologic↗
PubMed2001

Possible involvement of vitamin D receptor gene polymorphism in male patients with ossification of spinal ligaments.

Ossification of spinal ligaments (OSL) is a common form of myelopathy characterized by heterotopic bone formation in the spinal ligaments, predominantly in men. Although the etiology of OSL is not fully understood, previous studies have strongly suggested the involvement of genetic factors in this disease. To investigate the possible involvement of vitamin D receptor (VDR) gene polymorphism in Japanese male patients with OSL, we analyzed: (a) the VDR genotype defined by BsmI polymorphism in patients with obvious OSL and controls; and (b) the effect of 1,25-dihydroxyvitamin D3 on alkaline phosphatase (ALP) activity of spinal ligament cells derived from patients without OSL. With regard to the VDR genotype, of the patients with OSL (n = 27), none had the BB genotype (0%), one had the Bb genotype (4%), and 26 had the bb genotype (96%). In the control group (n = 97) three had the BB genotype (3%), 18 had the Bb genotype (19%), and 76 had the bb genotype (78%). As a result, the B allele frequency in patients with OSL (2%) was significantly lower than in controls (12%). 1,25-Dihydroxyvitamin D3, at concentrations of 10-9 and 10-8 M, significantly increased ALP activity of the ligament cells (n = 8), suggesting that 1,25-dihydroxyvitamin D3 is able to promote osteogenic differentiation of normal ligament cells. Among the Japanese, sensitivity to vitamin D has been reported to vary between the alleles of the VDR; i.e., bone mineral density (BMD) in patients without the B allele is increased by vitamin D treatment, whereas patients with the B allele do not show such an increase in BMD. The present investigation is a small preliminary study, but the findings suggest, for the first time, that the B allele of the VDR acts as an inhibitor in the pathogenesis of human male OSL.

24,25-Dihydroxyvitamin D 3↗
PubMed2001

Carboxylation of osteocalcin may be related to bone quality: a possible mechanism of bone fracture prevention by vitamin K.

Vitamin K is essential for the carboxylation of glutamic acid residues, such as osteocalcin. Recent studies have reported that vitamin K reduces vertebral and hip fractures without increasing bone mass in patients with osteoporosis, suggesting that vitamin K could affect bone quality. However, the mechanism is unknown. To investigate the involvement of the carboxylation of osteocalcin in bone quality, the present preliminary study examined serum bone markers and ultrasound velocity, a possible indicator of bone quality, in 14 healthy prepubertal children (eight boys and six girls) aged between 7 and 12 years. Venous blood was collected between 0800 and 0900 h after an overnight fast, and serum levels of intact, carboxylated and undercarboxylated osteocalcin, bone-specific alkaline phosphatase and type I procollagen carboxyl extension peptide were measured. Speed of sound in the right tibia was measured using a SoundScan 2000 Compact (Myriad Ultrasound System, Rehovot, Israel). As a result, there was no significant correlation between the serum bone markers and the Z score for the speed of sound. In contrast, the ratio of serum carboxylated osteocalcin to serum intact osteocalcin was positively correlated with the Z score for the speed of sound (r = 0.621, P = 0.016). These findings suggest, for the first time, that carboxylation of osteocalcin is related to bone quality. Further studies are needed to clarify the role of carboxylation of osteocalcin in bone, and this will provide a new insight into the mechanism of vitamin K treatment in osteoporosis.

Alkaline Phosphatase↗
PubMed2001

Involvement of interleukin-6 and prostaglandin E2 in periarticular osteoporosis of postmenopausal women with rheumatoid arthritis.

In experimental arthritis, blocking of the receptor activator of nuclear factor kappaB ligand (RANKL) by osteoprotegerin (OPG) treatment prevents bone loss but not inflammation, suggesting that there are inflammation-related factors that regulate RANKL and OPG. However, it is not known which factors regulate RANKL and OPG in human inflammation-induced bone loss. To clarify the inflammation-related factors that play a role in periarticular osteoporosis in patients with rheumatoid arthritis (RA), the synovial fluid and synovium of the knee joint, and the periarticular cancellous bone of the femoral condyle were collected at surgery from postmenopausal women with RA or osteoarthritis (OA). All patients with RA had radiologic bone loss on the femoral condyles, while such a loss was not observed in patients with OA. The present study examined: (i) tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta and IL-6 levels in synovial fluid: (ii) TNFalpha, IL-1beta and IL-6 messenger RNA (mRNA) expression in the synovium and the cancellous bone that contained bone marrow; and (iii) IL-6 and prostaglandin E2 (PGE2) production in cultured osteoblast-lineage cells derived from collagenase-treated cancellous bone fragments. Inflammation of the knee joints in patients with RA was confirmed by significantly higher proinflammatory cytokine levels in the synovial fluid and the synovium than those seen in patients with OA. In patients with RA, mRNA expression of IL-6, but not TNFalpha and IL-1beta, in the cancellous bone and IL-6 and PGE2 production in the osteoblast-lineage cells were significantly higher than in patients with OA. These findings suggest, for the first time, that IL-6 is involved in periarticular osteoporosis in postmenopausal women with RA. IL-6 and PGE2 released from osteoblast-lineage cells could be, at least in part, responsible for human inflammation-induced bone loss.

Aged↗