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Tadashi Nakamura

Publications and source records attributed to Tadashi Nakamura.

At least 19 recordsLinked to original sources
PubMed2006

A sensitive and reliable quantification method for mouse interleukin-12 p70 based on fluorometric sandwich ELISA (FS-ELISA).

Interleukin-12 (IL-12) p70 is an important cytokine secreted by antigen-presenting cells in response to antigenic stimulation; it is a heterodimer of p35 and p40 subunits. Here, we report a new, highly sensitive, and reliable method that employs fluorometric sandwich ELISA for quantification of the mouse IL-12 (moIL-12) p70 protein. Our method could quantify moIL-12 p70 in the range of approximately 0.5 to 500 pg/ml. In the assay, no signals were produced by the moIL-12 p40 monomer, homodimer [(p40)2], or mouse IL-23 even up to a concentration of 500 pg/ml; this ensures that our assay has a high specificity for moIL-12 p70. To demonstrate that our method can determine natural moIL-12 in real physiological/pathological samples, we monitored the moIL-12 p70 secretion from peritoneal exudative cells after lipopolysaccharide (LPS) stimulation. IL-12 p70 secretion as early as 3h after LPS stimulation was reliably detected due to the high sensitivity of the method.

Animals↗
PubMed2006

A functional M196R polymorphism of tumour necrosis factor receptor type 2 is associated with systemic lupus erythematosus: a case-control study and a meta-analysis.

OBJECTIVES: To perform a case-control study of a functional M196R polymorphism of tumour necrosis factor receptor type 2 (TNF-RII) in a Japanese population and a meta-analysis of all published reports on the polymorphism to investigate the association of the M196R polymorphism of TNF-RII with systemic lupus erythematosus (SLE). METHODS: The functional M196R polymorphism of TNF-RII was genotyped by using polymerase chain reaction combined with the subsequent single-strand conformation polymorphism (PCR-SSCP) analysis for screening, followed by nucleotide sequencing for confirmation. A total of 331 patients and 359 controls were subjected to a case-control study. A meta-analysis of the available case-control studies including all published data as well as our own data was performed to investigate the association of the functional M196R polymorphism of TNF-RII with SLE. RESULTS: Our case-control study did not show any significant association of a functional M196R polymorphism of TNF-RII with SLE, although there was a trend towards association. A meta-analysis of seven case-control studies in eight different ethnic populations including our own showed that 196M/R and 196R/R genotypes combined was significantly associated with an increased risk of SLE (odds ratio (OR) 1.29, 95% confidence interval (CI) 1.04 to 1.60; p = 0.02). Stratification by ethnicity showed a more significant association in Asians, including Japanese, Korean and Vietnamese (OR 1.40, 95% CI 1.10 to 1.78; p = 0.006). The effect of the 196R allele on SLE was not clear in Caucasians. CONCLUSIONS: The 196R allele of the functional M196R polymorphism of TNF-RII is a risk factor for SLE, especially in the Asian population.

Asian People↗
PubMed2006

Inhibition of influenza-virus-induced cytopathy by sialylglycoconjugates.

The anti-viral activity of gangliosides such as SPG (sialylparagloboside), GD1a, GM3, and GM4 was assessed by inhibition of the cytopathy of MDCK cells due to infection with the influenza virus A/PR/8/34. The inhibitory effect was in the following sequence: SPG>GD1a>GM3>GM4. The IC50 of SPG and GD1a was 7 and 70 microM, respectively, indicating that they are more effective than the representative inhibitor amantadine. Although 3'-sialyllactose (3'-SL) and 3'-sialyllactosamine (3'-SLN), which are identical to the terminal trisaccharides of GM3 and SPG, respectively, did not show any inhibitory effect, introduction of an amino group to the reducing end of 3'-SL following amidation with lauroyl chloride gave the inhibitory potency, which was comparable to that of GM3. These results suggest that the viral hemagglutinin recognizes exogenous sialyloligosaccharides rather than inherent sialyloligosaccharides expressed on MDCK cells, since introduction of the hydrophobic moiety to oligosaccharides might cause micelle formation.

Animals↗
PubMed2006

Primary culture of gustatory receptor neurons from the blowfly, Phormia regina.

Flies provide a powerful model system for exploring signaling systems in gustatory receptor neurons (GRNs). To elucidate the cellular and molecular bases of these signaling systems, we sought to develop techniques to dissociate GRNs. We developed a primary culture of GRNs isolated from the labella of the blowfly, Phormia regina, 4-5 days after pupation. Dissected labella were treated with papain in a low Ca2+ saline solution and shaken in Leibovitz's L-15 medium supplemented with 20-hydroxyecdysone, L-ascorbic acid, and trehalose with a test tube mixer. Released cells were plated and kept at 29 degrees C in a medium containing fetal bovine serum. After a minimum of 2 days in culture, we observed survival or growth of bipolar cells with the characteristic morphology of GRNs. We also examined taste responsiveness by monitoring intracellular Ca2+ with a Ca2+-sensitive fluorescent dye, fluo-3. For some bipolar cells, application of sucrose, NaCl, or LiCl for 5-20 s transiently increased the intracellular Ca2+ levels in cell bodies for 20-30 s. The primary cell culture described here is useful for functional analysis of GRNs.

Animals↗
PubMed2006

Reversible control of light reflection of a colloidal crystal film fabricated from monodisperse mesoporous silica spheres.

In this letter, we report a novel method for controlling the light reflection of a colloidal crystal. Highly monodisperse mesoporous silica spheres have been successfully organized into a hexagonally close-packed colloidal crystal film. Just by introducing water vapor into the fabricated colloidal film, the structural color and reflection spectra were changed dramatically because of water vapor adsorption occurring in the mesoporous channels. This phenomenon can be observed reversibly over five cycles. We are convinced that this is the first report on controlling the light reflection of a colloidal crystal film dynamically by taking advantage of adsorption properties inherent to mesoporous silica spheres.

Journal Article↗
PubMed2006

Primary biliary cirrhosis (PBC)-CREST overlap syndrome with coexistence of Sjögren's syndrome and thyroid dysfunction.

Calcinosis, Raynaud's phenomenon, oesophageal dysmotility, sclerodactyly, telangiectasia (CREST) syndrome, a limited form of systemic sclerosis, is sometimes complicated by primary biliary cirrhosis (PBC). A 52- and 61-year-old Japanese woman with PBC-CREST overlap syndrome accompanied by Sjögren's syndrome, and Hashimoto's thyroiditis, and Graves' disease, respectively, are reported. They had suffered from Raynaud's phenomena, sclerodactyly, morning stiffness, arthralgia, and sicca symptoms during these several years. They exhibited an increased level of alkaline phosphatase, gamma-glutamyl transpeptidase, positive antibodies against mitochondria and centromere, and hyperglobulinemia without any cholestatic symptoms. Histological findings from liver biopsy specimens were consistent with those of PBC. Clinically, they were diagnosed as both asymptomatic PBC and incomplete CREST syndrome. Their human leukocyte antigen typing showed both DR4 and DR8 positive. The association of the four autoimmune conditions is clinically and etiologically important. Although a combination of these diseases is rare, it is of importance to keep in mind that various autoimmune diseases could occur simultaneously. Of critical importance is that an active diagnostic attitude towards them is admirable, and that early diagnosis and therapy are needed.

CREST Syndrome↗
PubMed2006

HLA-DRB1*04 alleles in Japanese rheumatoid arthritis patients with AA amyloidosis.

OBJECTIVE: To compare the HLA-DRB1 shared epitope (SE) alleles in Japanese patients with rheumatoid arthritis (RA) and amyloid A (AA) amyloidosis versus those without AA amyloidosis. METHODS: The HLA-DRB1 alleles were genotyped for 91 RA patients without AA amyloidosis, 33 RA patients with AA amyloidosis, and 63 control subjects. HLA-DRB1 typing was performed by polymerase chain reaction, sequence-specific oligonucleotide probe hybridization method. RESULTS: Although a significant difference was not observed, the frequency of SE genotype was higher in RA patients with AA amyloidosis than in those without AA amyloidosis. All SE-positive RA patients with AA amyloidosis had *04 alleles (*0401, *0405, *0410), and a significant association of the presence of a double dose of *04 SE alleles with AA amyloidosis (OR 4.0, 95% CI 1.91-13.99) was observed. CONCLUSION: Our data suggest that presence of double *04 SE is associated with a higher risk of developing AA amyloidosis in Japanese patients with RA.

Aged↗
PubMed2005

Characterization of oligosaccharides in milk of a mink, Mustela vison.

Carbohydrates were extracted from a sample of milk from a mink, Mustela vison (Family Mustelidae). Free neutral and acidic oligosaccharides were isolated from the carbohydrate fraction and their chemical structures were compared with those of white-nosed coati (Nasua narica, Procyonidae) and harbour seal (Phoca vitulina, Phocidae) that we had studied previously. The ratio of free lactose to milk oligosaccharides was similar to that in milk of the white-nosed coati; in both species, this ratio was much lower than that in the milk of most eutherians. The neutral oligosaccharides of mink milk had alpha(1-3)-linked Gal or alpha(1-2)-linked Fuc residues at their non-reducing ends, as in the neutral oligosaccharides of white-nosed coati milk. Some of the neutral and acidic oligosaccharides, determined here, had been found also in harbour seal milk, but the harbour seal oligosaccharides did not contain alpha(1-3)-linked Gal residues.

Animals↗
PubMed2005

Aquaporin 7 deficiency is associated with development of obesity through activation of adipose glycerol kinase.

In adipocytes, hydrolysis of triglycerides results in the release of free fatty acids and glycerol. Aquaporin 7 (AQP7), a member of aquaglyceroporins, is known to permeabilize glycerol and water. We recently generated Aqp7-knockout (KO) mice and demonstrated that such mice have low plasma glycerol levels and impaired glycerol release in response to beta3-adrenergic agonist, suggesting that AQP7 acts as a glycerol gateway molecule in adipocytes for the efficient release of glycerol in vivo. Although there was no difference in body weight between WT and KO mice until 10 weeks of age, here we found that KO mice developed adult-onset obesity. The body weight and fat mass increased significantly in KO mice compared with WT mice after 12 weeks of age. Adipocytes of KO mice were large and exhibited accumulation of triglycerides compared with WT mice. The KO mice developed obesity and insulin resistance even at a young age after consumption of high-fat/high-sucrose diet. We demonstrated the enhanced glycerol kinase enzymatic activity in Aqp7-KO and -knockdown adipocytes. A series of our results indicate that AQP7 disruption elevates adipose glycerol kinase activity, accelerates triglycerides synthesis in adipocytes, and, finally, develops obesity.

3T3-L1 Cells↗
PubMed2005

Biochemical and physiological evidence that calmodulin is involved in the taste response of the sugar receptor cells of the blowfly, Phormia regina.

The gustatory system is essential for almost all animals. However, the signal transduction mechanisms have not yet been fully elucidated. We isolated labellar chemosensilla from blowfly, Phormia regina, and purified calcium binding proteins from the water soluble fraction. The most abundant calcium-binding protein was calmodulin. To investigate the role of calmodulin in taste transduction, electrophysiological responses were recorded with the calmodulin inhibitor, W-7. When we stimulated the labellar chemosensillum with sucrose plus W-7, a dose-dependent decrease of impulse frequency was observed when the concentration was <50 microM. In addition, when W-7 at 50 microM or higher concentration was added, an initial short-term impulse generation from the sugar receptor cell was observed, but this was followed by a silent period. When the sensillum was stimulated with W-7 plus a membrane-permeable cGMP analog, dibtyryl-cGMP or 8-bromo-cGMP, impulses of the sugar receptor cell were induced but the frequency was decreased. By the sidewall-recording method, we observed that the receptor potential induced by sucrose stimulation was decreased by W-7 in the sugar receptor cell, and corresponded with a disappearance of impulses. These data strongly suggest that the cGMP-gated channel generating receptor potential in the sugar receptor cell requires calmodulin for its gating.

Animals↗
PubMed2005

Occurrence of a unique sialyl tetrasaccharide in colostrum of a bottlenose dolphin (Tursiops truncatus).

Crude oligosaccharides were recovered from bottlenose dolphin (Tursiops truncatus) colostrum after chloroform/methanol extraction of lipids and protein precipitation, and purified using gel filtration, anion exchange chromatography and high performance liquid chromatography (HPLC). Their chemical structures characterized by NMR spectroscopy were as follows: GalNAc(beta1-4)[Neu5Ac(alpha2-3)]Gal(beta1-4)Glc, Neu5Ac(alpha2-3)Gal(beta1-4)Glc, Neu5Ac(alpha2-6)Gal(beta1-4)Glc and Gal(alpha1-4)Gal(beta1-4)Glc. The monosialyltetrasaccharide and neutral trisaccharide have not previously been found as free forms in any natural sources including milk or colostrum, although these structures have been found in the carbohydrate units of glycosphingolipids GM2 and Gb3.

Animals↗
PubMed2005

Association of visceral fat accumulation and plasma adiponectin with colorectal adenoma: evidence for participation of insulin resistance.

PURPOSE: Colorectal carcinogenesis is thought to be related to abdominal obesity and insulin resistance. To investigate whether visceral fat accumulation contributes to colorectal carcinogenesis, we examined its accumulation and the levels of the adipose tissue-derived hormone adiponectin in Japanese patients with colorectal adenoma. EXPERIMENTAL DESIGN: Fifty-one consecutive Japanese patients ages >/=40 years and with colorectal adenoma were subjected to measurement of visceral fat area by computed tomography scanning and plasma adiponectin concentration. The patients also underwent the 75-g oral glucose tolerance test. Insulin resistance was calculated by the homeostasis metabolic assessment (HOMA-IR) method. The controls were 52 Japanese subjects ages >/=40 years and without colorectal polyp. Cigarette smokers and subjects who consumed alcohol (>/=30 g ethanol/d) were excluded. RESULTS: The patients with colorectal adenoma showed significantly more visceral fat area and significantly less plasma adiponectin concentration in comparison with the controls [odds ratio (OR), 2.19; 95% confidence interval (95% CI), 1.47-3.28; P < 0.001 and OR, 0.24; 95% CI, 0.14-0.41; P < 0.001, respectively] by logistic regression analysis. HOMA-IR index was also associated with colorectal adenoma (OR 2.60; 95% CI, 1.20-5.64; P = 0.040). Visceral fat area and adiponectin were associated with adenoma number (1, 2, >/= 3), the size of the largest adenoma (<10 and >/=10 mm), and adenoma histology (tubular and tubulovillous/villous). CONCLUSIONS: These results suggest an association of visceral fat accumulation and decreased plasma adiponectin concentration with colorectal adenoma in Japanese patients. This study may offer a new insight to understanding the relationship of colorectal carcinogenesis with abdominal obesity and insulin resistance.

Adenoma↗
PubMed2005

Preliminary analysis of the GABA-induced current in cultured CNS neurons of the cutworm moth, Spodoptera litura.

Properties of GABA-induced current in cultured CNS (ganglion) neurons of cutworm moths (Spodoptera litura) were studied using a whole-cell patch-clamp technique. CNS neurons ranging from 10 to 20 microm in diameter were cultured for 4-7 days in MGM-464 medium. GABA-induced a current response in these neurons in a sigmoidally dose dependent manner where the Hill coefficient and EC50 were 2.2 and 33.0 microM, respectively. The reversal potential of GABA-induced current was -2.5 mV, which is close to the Cl- equilibrium potential that was calculated from chloride ion concentrations in the present experimental environment. Furthermore, the GABA-induced current response depended on the extracellular chloride ion concentration, indicating that the receptor regulates the Cl- permeability of cells. The GABA-induced current was completely inhibited by the GABA(A) antagonist, SR95531, and activated by the GABA(A) agonist, muscimol but not by the GABA(B) agonist, baclofen. On the other hand, the GABA(C) agonist, CACA, also induced a little smaller current than the GABA-induced response. The pharmacological behaviors of the GABA-induced currents suggest that these cells contain GABA receptors that belong to the GABA receptor family including the Rdl GABA receptors identified in Drosophila neurons.

Animals↗
PubMed2005

N-acetylglucosaminyltransferase I activity of bovine oviduct epithelial cells: stimulation by luteinizing hormone, vascular endothelial growth factor and tumor necrosis factor alpha.

N-acetylglucosaminyltransferase I (GnT I; EC 2.4.1.101), which catalyzes the first step in the conversion of oligomannose to complex or hybrid N-glycans of glycoproteins, was found in media cultured with bovine oviduct epithelial cells (BOEC) obtained from non-pregnant cows during the follicular phase. Combined treatment with specific hormones increased GnT I release from BOEC. Luteinizing hormone (LH; 10 ng/ml) alone slightly, but together with 17beta-estradiol (E2; 1 ng/ml), synergistically increased GnT I activity. Vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF) alpha, which have been shown to have their highest activities in the bovine oviduct during the periovulatory period, also increased in GnT I activity. This study provides the first evidence of an increase of GnT I release from BOEC in vitro, and shows that endocrine as well as local factors such as LH, VEGF and TNFalpha increase this activity. The results suggest that GnT I activity in the bovine oviduct may contribute to the induction of glycosylation and thereby contributing to the provision of the optimal microenvironment for fertilization and early development of the embryos.

Animals↗
PubMed2005

Gq alpha subunit mediates receptor site-specific adaptation in the sugar taste receptor cell of the blowfly, Phormia regina.

The gustatory system is essential for almost all animals. The recent identification of G protein-coupled receptor proteins (GPCRs) has progressed molecular biological studies of gustatory systems, although the signal transduction mechanisms have not yet been fully elucidated. In vision and olfactory receptor cells, Gq class G protein is known to be a major signal transducer. By functional blocking of intrinsic Gq with an anti-Gq/11alpha antibody, we investigated the roles of Gq in the sugar receptor cell of the blowfly, Phormia regina. Before and after introduction of the anti-Gq/11alpha antibody into the cell through the DOC-permeabilized cell membrane, we recorded the responses of the receptor cell to sucrose and d-fructose, which stimulate different receptor sites, respectively. The initial impulse frequency in response to either sucrose or D-fructose was not changed by antibody introduction, whereas the adaptation rate in sucrose stimulation, but not fructose stimulation, became slower after antibody introduction. These results indicate that: (1) Gq is a regulator of adaptation in the sugar receptor cell of Phormia, rather than a transducer, and (2) different adaptation mechanisms are promoted by stimulations with sucrose and D-fructose.

Adaptation, Physiological↗
PubMed2005

Identification of unique lipoprotein subclasses for visceral obesity by component analysis of cholesterol profile in high-performance liquid chromatography.

OBJECTIVE: The contribution of visceral fat accumulation to the development of coronary heart disease was previously reported, but the relation between visceral fat accumulation and serum lipoprotein subclasses was unknown. METHODS AND RESULTS: We examined the relation of lipoprotein subclasses with visceral fat accumulation in 62 male subjects (aged 22 to 67 years) with visceral fat syndrome or obesity. Cholesterol levels in very low-density, low-density, and high-density lipoprotein subclasses (VLDL, LDL, and HDL) were determined by computer-assisted high-performance liquid chromatography. Subcutaneous fat area and visceral fat area were measured by computed tomographic scanning. There was no significant correlation between the subcutaneous fat area and the cholesterol levels in all lipoprotein subclasses. In contrast, the visceral fat area was correlated positively (P<0.002) with VLDL and LDL subclasses, except for large LDL, but negatively (P<0.001) with those in large and medium HDL subclasses. The observed positive correlations of small and very small LDL subclasses remained significant (P<0.005) after adjustment for serum cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol, respectively, but a significant negative correlation (P<0.005) of large LDL was obtained after adjustment for LDL cholesterol. CONCLUSIONS: These findings indicate that this simple high-performance liquid chromatography method may be applied for easy detection and evaluation of abnormal distribution of lipoprotein subclasses.

Adipose Tissue↗
PubMed2005

Effectiveness of anti-folate receptor beta antibody conjugated with truncated Pseudomonas exotoxin in the targeting of rheumatoid arthritis synovial macrophages.

OBJECTIVE: To define the distribution of folate receptor beta (FRbeta)-expressing cells in various tissues, including rheumatoid arthritis (RA) synovial tissues, and to verify the effects of an immunotoxin composed of an anti-FRbeta monoclonal antibody (mAb) and truncated Pseudomonas exotoxin A (PEA) on apoptosis and tumor necrosis factor alpha (TNFalpha) production by adherent synovial mononuclear cells from RA patients. METHODS: Anti-FRbeta mAb were produced by immunizing mice with FRbeta-transfected murine pre-B cells. The distribution of the FRbeta antigen was examined by immunohistochemical analysis using anti-FRbeta mAb and macrophage-specific anti-CD163 mAb. Anti-FRbeta mAb was chemically crosslinked with truncated PEA. FRbeta-expressing macrophages were produced by the transfection of adenovirus vector containing the FRbeta gene. Apoptotic cells were detected by staining with propidium iodide. TNFalpha was measured by enzyme-linked immunosorbent assay. RESULTS: FRbeta-expressing cells were not present in peripheral blood leukocytes and their activated cells. In all of the tissues examined, most FRbeta-expressing cells were CD163+. The immunotoxin significantly induced the apoptosis of FRbeta-transfected macrophages and adherent RA synovial mononuclear cells and inhibited TNFalpha production by adherent RA synovial mononuclear cells. CONCLUSION: We demonstrated the limited distribution of FRbeta-expressing cells in various tissues. The immunotoxin targeting FRbeta-expressing cells will provide a therapeutic tool for rheumatoid synovitis.

ADP Ribose Transferases↗