Search PubMed⌕ Search

Biomedical subjects

Shigeru Yamamoto

Publications and source records attributed to Shigeru Yamamoto.

53 records · Page 3Linked to original sources
PubMed2003

Further evidence regarding the effect of dietary protein on oral tolerance against beta-lactoglobulin through Th1-mediated immune response in mice.

Oral tolerance is a potential strategy for preventing or minimizing aberrant immune responses. Although, oral tolerance has been extensively studied, to date the effects of dietary protein on the induction of oral tolerance are poorly understood. We have previously shown that restricted dietary protein induces oral tolerance to ovalbumin. This study was designed to investigate whether or not such tolerance occurs with beta-lactoglobulin (BLG) instead of ovalbumin (OVA) and if the tolerance resulting from this feeding regimen involves Th1-mediated immune response. Female BALB/c mice fed either 20% or 5% dietary protein were given 5 mg BLG or water orally for four consecutive days and then immunized intraperitoneally (ip) twice with BLG at 3-wk intervals. Oral tolerance induction was compared in BLG-fed and water-fed mice by measuring total IgE, BLG-specific antibodies, footpad reactions, splenocyte proliferation, and cytokine production. When mice were given BLG orally before ip immunization, the Th1-mediated immune responses (production of IL-2, IFN-gamma, and IgG2a) were significantly reduced, whereas the Th2-mediated immune responses (production of IL-4 and IgG1) were unchanged. The Th1-mediated immune responses were markedly down-regulated in mice fed 5% protein as compared to those in mice fed 20% protein. Moreover, the production of total IgE, BLG-specific IgE, splenocyte proliferation, and footpad reactions were more reduced in mice fed 5% protein than those in mice fed 20% protein. The present study provides evidence that dietary protein plays an important role in the induction of oral tolerance against BLG as the result of, clear down-regulation of Th1 helper activity accompanied by a reduction in IgE.

Administration, Oral↗
PubMed2003

IgE responses in mice fed moderate protein deficient and high protein diets.

While severe protein energy malnutrition (PEM) has been known to depress several immune functions, allergies are suppressed by decreasing IgE and impairing vascular permeability and mast cell functions. To address the effect of moderate protein malnutrition without growth arrest and protein hypernutrition on type I allergy, we examined the effect of various levels of protein nutrition on allergy at humoral immunity and the regulation of Th cell function levels. Mice fed 100 g/kg (moderate protein malnutrition; MPM), 200 g/kg (normal protein nutrition; PN) and 400 g/kg (protein hypernutrition; PH) protein diets were intraperitoneally sensitized to ovalbumin (OVA) in aluminum hydroxide. Higher elevations of OVA-specific IgE and total IgE in the serum were observed in the PH group as compared to the PN group. However, OVA-specific IgE in the MPM group was not significantly different from that in the PN group, although the former appeared higher than the latter. While CD3, CD4, CD8 and B220 expressions in the splenic lymphocytes were decreased in the MPM group, B220 expressions were increased in the PH group. Splenic lymphocyte proliferative responses to OVA were augmented in the PH group and depressed in the MPM group. IFN-gamma production from splenic lymphocytes was significantly decreased; however, IL-4 production was not affected significantly in the MPM group, and increased in the PH group. These findings suggest that immune functions to specific antigens in the MPM state are depressed at the cytokine level but not in terms of IgE responses. They also suggest that immune functions become Th2-predominant in the PH state, resulting in an increased risk of type I allergy.

Animals↗
PubMed2003

Oolong tea increases energy metabolism in Japanese females.

Oolong tea is a traditional Chinese tea that has long been believed to be beneficial to health such as decreasing body fat. We were interested in this assertion and tried to evaluate the effect of oolong tea on energy expenditure (EE) in comparison with green tea. The subjects were eleven healthy Japanese females (age 20+/-1 y; body mass index (BMI) 21.2+/-2.5 kg/m2) who each consumed of three treatments in a crossover design: 1) water, 2) oolong tea, 3) green tea. Resting energy expenditure (REE) and EE after the consumption of the test beverage for 120 min were measured using an indirect calorimeter. The cumulative increases of EE for 120 min were significantly increased 10% and 4% after the consumption of oolong tea and green tea, respectively. EE at 60 and 90 min were significantly higher after the consumption of oolong tea than that of water (P<0.05). In comparison with green tea, oolong tea contained approximately half the caffeine and epigallocatechin galate, while polymerized polyphenols were double. These results suggest that oolong tea increases EE by its polymerized polyphenols.

Adult↗
PubMed2002

Expression of vascular endothelial growth factor family messenger RNA in diseased thyroid tissues.

PURPOSE: Four different factors have recently been identified in the vascular endothelial growth factor (VEGF)family, namely, VEGF-A, VEGF-B, VEGF-C, and VEGF-D. We investigated the expression of each VEGF gene in diseased thyroids using the multiplex reverse transcription-polymerase chain reaction (RT-PCR) method. METHODS: The subjects were 61 patients (11 with Graves' disease, 41 with primary papillary carcinoma, and 9 with recurrent papillary carcinoma). A semiquantitative multiplex RT-PCR was designed to compare the RT-PCR products of each VEGF mRNA with beta-actin mRNA products to determine the relative expression. RESULTS: VEGF-A and VEGF-B mRNA were expressed in all patients, VEGF-C mRNA was expressed in 58 (95.1%), and VEGF-D mRNA was expressed in 28 (46.0%). The expression of VEGF-D mRNA was significantly lower than that of the other VEGF mRNAs. The patients with papillary carcinoma and nodal involvement had significantly higher expression of the VEGF-C mRNA than those without nodal involvement. The expression of VEGF-C mRNA did not directly represent nodal involvement; however, the number of metastatic lymph nodes was positively correlated with the expression of VEGF-C mRNA in the primary tumor. CONCLUSIONS: To our knowledge, this is the first clinical study on VEGF-B, VEGF-C, and VEGF-D mRNA expression in diseased thyroids. Although VEGF-C mRNA expression was required for nodal involvement, we assume that other factors and mechanisms are also involved.

Adolescent↗
PubMed2002

Glutamine and arginine affect Caco-2 cell proliferation by promotion of nucleotide synthesis.

OBJECTIVE: We tested our hypothesis that 1) the major effect of Gln is as a nitrogen donor, not an energy source, for nucleotides (NT) and 2) the supplementation of culture medium with arginine (Arg) decreases the flux of glutamine (Gln) for conversion to Arg, thus accelerating NT synthesis. METHODS: Various concentrations of nucleosides (NS+NT) Gln, and glutamate (Glu) in culture were tested for their effect on Caco-2 cell proliferation. (Arg was tested in media with and without Gln to evaluate the Gln pathway. The incorporation of (15)N from L-[5-(15)N]-Gln into NTs of DNA was measured under different NS + NT and Arg concentrations.) RESULTS: The proliferation of Caco-2 cells was increased by NS + NT and Gln supplementation, but not by Glu. The effective concentration of NS + NT was 100-fold smaller than that of Gln. An Arg effect was observed only in the presence of Gln. The NT synthesis from Gln, as indicated by (15)N incorporation from L-[5-(15)N]-Gln, was increased by Arg supplementation and decreased by NS + NT supplementation. CONCLUSION: These results support our hypothesis that the effects of Gln and Arg on Caco-2 cell proliferation are by the promotion of NT synthesis and that the major role of Gln is not energy supply.

Arginine↗
PubMed2002

Serum fatty acids, lipoprotein (a) and apolipoprotein profiles of middle-aged men and women in South Vietnam.

In Vietnam, increasing fat consumption is a trend recognized recently in urban areas. To obtain a reasonable nutrition status and prevent cardiovascular disease (CVD), it is necessary to obtain information on habitual fat intake and biochemical parameters as risk factors for CVD in Vietnamese populations. Therefore, from the analysis of serum fatty acid composition, fat consumption patterns in Vietnamese populations in South Vietnam, with different incomes, are discussed in this study. In addition, some risk factors for premature CVD, serum lipoprotein (a) and apolipoprotein concentrations are also assessed in these Vietnamese populations. The study was carried out in men and women aged 40-59 in three different districts: urban (n = 100), suburban (n = 98) and rural (n = 98). The results of serum fatty acid composition analysis reflected differences in quality fat intake among the three populations. The urban population was estimated to consume more vegetable oil but less fish than their rural counterparts. Although serum lipoprotein (a) and apolipoprotein B levels were below the ranges associated with atherogenesis, ongoing attention to dietary fat intake for the prevention of CVD in Vietnamese populations is required.

Adult↗
PubMed2002

Simultaneous analysis of retinol, beta-carotene and tocopherol levels in serum of Vietnamese populations with different incomes.

In this study, we clarified the status of the fat-soluble vitamins retinol and tocopherol, as well as beta-carotene, as antioxidants in the prevention of cardiovascular disease in middle-aged Vietnamese populations with different incomes. In order to measure simultaneously the serum concentrations of retinol, beta-carotene and tocopherol, we carried out high-performance liquid chromatography analysis with three separate detectors. The analytical method was modified, omitting the saponification process, and used a multi-evaporating system with dry ice. This allowed the analysis to proceed more rapidly, use a small amount of serum (40 microL) and be free of hexane contamination to the environment. The analyses reflected an adequate status of vitamin A (serum retinol = 20 microg/dL), but inadequate status of beta-carotene and vitamin E (serum beta-carotene <40 microg/dL; serum tocopherol < 600 microg/dL) in all three Vietnamese populations. As large numbers of Vietnamese subjects were observed with very low serum concentrations of beta-carotene and tocopherol, higher consumptions of green and yellow vegetables, fruits, vegetable oils and other foods rich in vitamin E are recommended for these Vietnamese populations.

Adult↗
PubMed2002

Genetic studies on reference strains of mutans streptococci.

Twenty four reference strains (serotype a-h) belonging to the mutans group of streptococci were compared for DNA fragment patterns of rDNA after treatment with Hind III. It was shown that Streptococcus cricetus (serotype a), S. rattus (serotype b), and S. downei (serotype h) reveals comparatively homogeneous patterns while S. mutans (serotype c, e and f) exhibits differences between the different serotypes as well as within single serotypes. S. sobrinus had an intermediary diversity. These data support the previous findings that S. mutans is heterogeneous at the serological, biochemical and genetical level.

Animals↗
PubMed2002

Isolation and characterization of a beta-primeverosidase-like endo-manner beta-glycosidase from Aspergillus fumigatus AP-20.

A novel beta-glycosidase-producing microorganism was isolated from soil and identified as Aspergillus fumigatus AP-20 based on its taxonomical characteristics. The enzyme was found to be an extracellular protein in the culture of the isolated fungus and was purified 88-fold by fractionation with ammonium sulfate followed by successive column chromatographies on phenyl-Sepharose HP and Mono P HR. The molecular mass was estimated to be 47 kDa by SDS-PAGE and the isoelectric point to be pH 6.0 by isoelectric focusing. The purified enzyme was highly specific for a substrate, p-nitrophenyl beta-primeveroside (6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside), which was cleaved in an endo-manner into primeverose and p-nitrophenol.

Aspergillus fumigatus↗
PubMed2002

Distribution and immune responses resulting from oral administration of D-limonene in rats.

We investigated the relationship between the absorptive pathway and the immune responses of the lung, particularly the phagocytic function of alveolar macrophages (Mphi) after oral administration of D-limonene in rats. D-Limonene was orally administered in oily solution with a stomach tube in thoracic duct-cannulated rats, and the lymphatic output of D-limonene was measured. D-Limonene levels reached a maximum in thoracic duct lymph and lung 3 h after its oral administration. It also significantly increased in bronchoalveolar lavage fluid (BALF) and alveolar Mphi, in which there was frequently a focal exudation of lipid droplets containing D-limonene into the alveolar cavity through alveolar capillary walls. Second, D-limonene orally given to rats (250, 500, 1,000 mg/kg/d) for 8 consecutive days resulted in a marked increase in both the number and the phagocytic activity of alveolar Mphi compared to the controls. BALF from rats dosed with D-limonene (1,000 mg/kg/d) enhanced the phagocytic activity of alveolar Mphi from control rats because the dose was prolonged. The activity of alveolar Mphi following in vitro incubation with D-limonene also increased in a dose-dependent manner. An oral administration of D-limonene enhanced the Con A-stimulated proliferation of splenocytes. These results suggest that D-limonene taken up from the thoracic duct lymph moves to the lung and directly activates the immune response of alveolar MO there, or indirectly activates it through activated lymphocytes.

Absorption↗
PubMed2002

Nutrition during pregnancy may be associated with allergic diseases in infants.

The prevalence of allergic diseases is high in Japan, even in infants. Their risk for developing allergies is influenced by the antigens in the mother's diet during pregnancy. We hypothesized that, apart from the antigens, hypersensitivity induced through high energy and nutrient intake by mothers during pregnancy may be a factor for allergic diseases in their babies. In this study, we tried to confirm our hypothesis. Allergy histories of parents and their infants, body characteristics and food and nutrient intake were measured by a questionnaire and a food frequency questionnaire, respectively. A total of 2,642 responses were obtained (return rate, 94.7%). The major allergic diseases in the infants were atopic dermatitis (6.0%), food allergy (3.7%) and bronchial asthma or asthmatic bronchitis (3.2%). About 60% of the infants with allergies had a family history of allergies. Family history of allergy, age of infant, order of birth, head and chest circumferences of infants, BMI of mothers before pregnancy and delivery and intake of lipids (fat and vegetable oil) and vegetables by mothers related positively, and the intake of protein, carbohydrates and milk and its products correlated negatively with allergic diseases in the infants (p < 0.05). The results, together with previous reports, suggest that a high intake of energy and lipids (fat and vegetable oil) during pregnancy may accelerate allergic diseases in infants.

Adult↗
PubMed2002

Low-protein diet induces oral tolerance to ovalbumin in mice.

The suitable development of oral tolerance against ingested dietary foods is of critical importance to escaping food allergy. Using mice as an animal model for oral tolerance against ovalbumin (OVA) as a dietary antigen, we investigated the effects of dietary protein on their immunological tolerance. Female BALB/c mice fed either a 20% or 5% protein diet were orally administered 5 mg of OVA for four consecutive days, then immunized intraperitoneally with 100 microg of OVA. The immunized group of mice were fed and treated in the same manner, except that they received orally distilled water for four consecutive days before receiving intraperitoneal immunization with the antigen. Immunization alone with OVA elevated the total IgE and induced the production of OVA-specific antibodies IgE, IgG, IgG1, and IgG2a in the sera of both the 20% and 5% protein diet groups. The oral administration of OVA to mice before intraperitoneal immunization significantly reduced the total IgE and OVA-specific antibodies in mice fed 5% protein diet, but it had hardly any effect on those in mice fed a 20% protein diet. When spleen cells from these groups of mice were cultured with OVA as a mitogen, they responded substantially to OVA in the immunized groups fed 20% and 5% protein diets and in the presensitized group fed 20% protein, but those from the presensitized group fed a 5% protein diet did not respond. Furthermore, when IL-4 was assayed in the spleen cell cultures of the 20% and 5% groups, mice in the presensitized group fed a 5% protein diet produced a significantly less amount of IL-4 than those fed a 20% protein diet. Moreover, irrelevant to the protein amount in the diet, the production of IFN-gamma from spleen cell cultures dramatically decreased in the group without presensitization and profoundly increased in the presensitized group of mice fed a 5% protein diet. These findings suggest that a low-protein diet leads to an induction of oral tolerance against dietary antigens; this appears to involve a clear down-regulation of Th2 cytokine, IL-4.

Administration, Oral↗
PubMed2002

Inhibition of infiltration and angiogenesis by thrombospondin-1 in papillary thyroid carcinoma.

PURPOSE: Angiogenesis is essential for tumor growth and is controlled by the balance between angiogenic and antiangiogenic factors. We studied the expression of angiogenic factors and antiangiogenic factors in papillary thyroid carcinoma. EXPERIMENTAL DESIGN: We investigated immunohistochemically the expression patterns and levels of antiangiogenic factor and its receptor, thrombospondin-1 (TSP-1) and CD36, and four angiogenic factors, vascular endothelial growth factor (VEGF), VEGF-C, angiopoietin-2 (Ang-2), and Tie-2, in the primary tumors of 75 papillary thyroid carcinoma patients. We also examined the microvessel count (MVC), using CD31 staining. RESULTS: VEGF expression strongly correlated with other angiogenic factors. The cytoplasm of cancer cells stained positive for all factors. Tie-2 and TSP-1 receptor also appeared in endothelia of microvessels. TSP-1 inversely correlated with the degree of invasion of the primary tumor to other adjacent organs and with MVC. A higher MVC correlated with poorer survival. To clarify the balance between angiogenic and antiangiogenic factors in the same tumor, we calculated the ratio of each angiogenic factor against TSP-1 as the antiangiogenic factor. The ratios VEGF/TSP-1, VEGF-C/TSP-1, and Ang-2/TSP-1 significantly correlated with a higher MVC. Furthermore, the ratios VEGF/TSP-1 and Ang-2/TSP-1 significantly correlated with the degree of infiltration. CONCLUSIONS: To the best of our knowledge, this is the first report demonstrating that the balance between angiogenic and antiangiogenic factors correlates with distinct invasion to other organs and neovascularization of papillary thyroid carcinoma.

Adolescent↗
PubMed2002

Eicosapentaenoic acid inhibits CSF-induced human monocyte survival and maturation into macrophage through the stimulation of H2O2 production.

Human studies suggest a beneficial effect of eicosapentaenoic acid (EPA)-supplemented diets on atherosclerotic and atherothrombotic disorders as well as autoimmune and inflammatory diseases and tumors. The effects of EPA on human monocyte survival and maturation into macrophage are not yet known. We studied the effects of EPA on the survival and development into macrophage of human monocyte treated with colony-stimulating factor (CSF). We have found that EPA induces cell death of the monocyte via apoptosis, even in the presence of M-CSF or GM-CSF, and inhibits differentiation from the monocyte to macrophage by inducing H2O2 production. In contrast to the effect of EPA on monocytes, EPA did not induce cell death of monocyte-derived macrophages. Such an apoptosis inducing effect on monocytes by EPA may contribute to the efficacy of EPA in atherosclerosis and autoimmune diseases.

Apoptosis↗
PubMed2002

Resection of thymic carcinoma in a patient with thoracic aortic aneurysm.

A 72-year-old man with a history of brain infarction presented with left sided anterior chest pain secondary to a thymic carcinoma. He received induction radiotherapy, 45 Gy. Preoperative computed tomography showed the tumor was adherent to a thoracic aortic aneurysm (TAA) which had extensive mural thrombus and calcification. To obtain adequate exposure without exerting tension on the fragile aneurysmal wall, ribs were resected to allow us to separate the tumor from the TAA, after which median sternotomy was performed uneventfully, creating generous exposure. The tumor had invaded the sternum, ribs, innominate vein, phrenic and recurrent laryngeal nerves, and lung. The tumor was removed en bloc, and the chest wall was reconstructed. Intra- and post-operative brain infarction and rupture of the TAA were avoided. The patient is alive and well without recurrence 10 months after surgery.

Aged↗
PubMedDate not supplied

Genistein suppresses antigen-specific immune responses through competition with 17beta-estradiol for estrogen receptors in ovalbumin-immunized BALB/c mice.

OBJECTIVE: The aim of this study was to determine the effects of phytoestrogen genistein on antigen (Ag)-specific immune responses and elucidate the mechanisms underlying those effects. METHODS: Ovalbumin (OVA)-immunized BALB/c mice were administered genistein for 35 d, and OVA-specific immune responses were examined by measuring OVA-specific proliferative responses, production of cytokines, and antibody responses. To assess the effect of genistein on antibody responses to thymus-independent Ag, mice were immunized with 2,4,6-trinitrophenyl (TNP)-Ficoll instead of OVA. Effect of genistein on the functions of CD11c(+) dendritic cells was also examined. Finally, to determine the contribution of estrogen receptor to genistein-mediated immune regulation, mice that had been administered genistein were treated with the estrogen receptor antagonist ICI 182,780 and OVA-specific proliferative responses were examined. RESULTS: OVA-specific proliferative responses and interferon-gamma production levels were decreased in mice administered 20 mg/kg genistein compared with those in control mice without reduction in responses to anti-CD3 monoclonal (m)antibody. The level of OVA-specific immunoglobulin (Ig)G1 was also decreased in mice administered genistein. Levels of OVA-specific IgG2a and IgG2b production and interleukin-4 production in response to OVA were not significantly different but tended to decrease in genistein-treated mice. Genistein administration did not influence the TNP-specific IgM and IgG levels. Furthermore, genistein did not affect the Ag-presenting activity of CD11c(+) dendritic cells. Treatment with ICI 182,780 decreased OVA-specific proliferative responses, but genistein did not suppress these responses synergistically in mice treated with ICI 182,780. CONCLUSIONS: The results of this study suggest that genistein suppresses Ag-specific immune responses. The mechanism underlying the suppression is responsible for the competition of genistein with endogenous 17beta-estradiol for estrogen receptors.

Animals↗