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Biomedical subjects

Takashi Tobe

Publications and source records attributed to Takashi Tobe.

18 recordsLinked to original sources
PubMed2006

Impact of increased plasma serotonin levels and carotid atherosclerosis on vascular dementia.

Serotonin (5-HT), a potent vasoconstrictor in the large cerebral arteries, is considered to play a key role in atherothrombosis and to be implicated in ischemic cerebrovascular events followed by delayed neuronal death. The present study aims at evaluating the relationship between plasma levels of 5-HT and vascular dementia (VaD) caused by stroke or atherosclerotic small vessel disease. Carotid artery intima-media thickness (IMT), plaques, plasma 5-HT levels and atherosclerotic parameters were determined in 20 patients with VaD and 40 age-matched controls. Age, gender, body mass index, systolic and diastolic blood pressure, fasting plasma glucose levels and serum levels of insulin, triglycerides, high-density lipoprotein cholesterol, leptin, adiponectin and interleukin-6 and plasma levels of plasminogen activator inhibitor-1 were not significantly different between the two groups. Serum levels of insulin-like growth factor-1 (IGF-1) were significantly lower in VaD patients than in controls. Plasma 5-HT levels, serum levels of hepatocyte growth factor (HGF), low-density lipoprotein (LDL) cholesterol and high-sensitive C-reactive protein (hs-CRP), max IMT and plaque frequency were significantly greater in VaD patients than in controls. There was a significant positive correlation of max IMT with 5-HT or HGF levels. Multiple logistic regression analysis revealed that increased plasma levels of 5-HT and carotid plaque prevalence had significantly independent association with VaD as compared with serum levels of IGF-1, HGF, LDL cholesterol and hs-CRP. These results suggest that increased plasma levels of 5-HT and carotid atherosclerotic plaques may be involved in the pathogenesis and progression of VaD.

Aged↗
PubMed2006

Unique membrane interaction mode of group IIF phospholipase A2.

The mechanisms by which secretory phospholipases A(2) (PLA(2)s) exert cellular effects are not fully understood. Group IIF PLA(2) (gIIFPLA(2)) is a structurally unique secretory PLA(2) with a long C-terminal extension. Homology modeling suggests that the membrane-binding surface of this acidic PLA(2) contains hydrophobic residues clustered near the C-terminal extension. Vesicle leakage and monolayer penetration measurements showed that gIIFPLA(2) had a unique ability to penetrate and disrupt compactly packed monolayers and bilayers whose lipid composition recapitulates that of the outer plasma membrane of mammalian cells. Fluorescence imaging showed that gIIFPLA(2) could also readily enter and deform plasma membrane-mimicking giant unilamellar vesicles. Mutation analysis indicates that hydrophobic residues (Tyr(115), Phe(116), Val(118), and Tyr(119)) near the C-terminal extension are responsible for these activities. When gIIFPLA(2) was exogenously added to HEK293 cells, it initially bound to the plasma membrane and then rapidly entered the cells in an endocytosis-independent manner, but the cell entry did not lead to a significant degree of phospholipid hydrolysis. GIIFPLA(2) mRNA was detected endogenously in human CD4(+) helper T cells after in vitro stimulation and exogenously added gIIFPLA(2) inhibited the proliferation of a T cell line, which was not seen with group IIA PLA(2). Collectively, these data suggest that unique membrane-binding properties of gIIFPLA(2) may confer special functionality on this secretory PLA(2) under certain physiological conditions.

Amino Acid Sequence↗
PubMed2006

Adiponectin plays an important role in efficient energy usage under energy shortage.

Adiponectin is an adipose tissue-specific secretory protein known to be an insulin-sensitizing protein. In this study, we generated adiponectin sense and antisense transgenic (Tg) mice to investigate whether adiponectin plays a role in the regulation of energy homeostasis during the growth stage. Spontaneous motor activity of antisense Tg mice were markedly reduced during fasting, particularly in young female mice, compared with wild type (Wt) and sense Tg mice. Furthermore, both body weight and adipose tissue mass of the antisense female Tg mice drastically reduced during fasting. To examine the relationship between the collapse of abdominal white adipose tissue (WAT) and serum adiponectin level, we measured the expression of genes related to energy expenditure, such as uncoupling protein (UCP). Notably, the mRNA of UCP1 in the WAT of antisense Tg female mice was markedly less than that of Wt mice and the UCP1 mRNA was strongly increased during fasting. These findings suggest that the serum adiponectin is important to maintaining energy homeostasis under energy shortage conditions, such as over female pubertal development.

Adiponectin↗
PubMed2006

A novel enzyme-linked immunosorbent assay specific for high-molecular-weight adiponectin.

Human plasma contains at least three forms of adiponectin: a trimer, a hexamer, and a high-molecular-weight (HMW) multimer. We purified HMW adiponectin from human plasma using its affinity to gelatin and obtained monoclonal antibodies against it. On Western blot analysis, the reactivity of these monoclonal antibodies was shown to be restricted to a non-heat-denatured form of adiponectin molecules. On heating, the collagen-like domain of adiponectin molecules became denatured, and thus the trimer form could not be maintained. From these, monoclonal antibodies against HMW adiponectin were suggested to react with the intact trimer of adiponectin. With these monoclonal antibodies, we developed a sandwich ELISA system for quantifying adiponectin in human serum. Its specificity was verified by analysis of serum fractions separated by gel-filtration chromatography, and our ELISA system was found to be HMW adiponectin-specific. With this novel ELISA, the HMW adiponectin concentrations were 8.4 +/- 5.5 microg/ml (mean +/- SD) in healthy women and 6.2 +/- 3.6 microg/ml in healthy men. Also, serum with a lower HMW adiponectin concentration was shown to have a lower HMW ratio (i.e., HMW adiponectin/total adiponectin).

Adiponectin↗
PubMed2006

Influence of SNPs in cytokine-related genes on the severity of food allergy and atopic eczema in children.

Although many single nucleotide polymorphism (SNP) studies have reported an association of atopy, allergic diseases and total serum immunoglobulin E (IgE) levels, almost all of these studies sought risk factors for the onset of these allergic diseases. Furthermore, many studies have analyzed a single gene and hardly any have analyzed environmental factors. In these analyses, the results could be masked and the effects of other genes and environmental factors may be decreased. Here, we described the correlation between four genes [interleukin (IL)-4 (C-590T), IL-4 receptor (A1652G), FCER1B (G6842A) and STAT6 (G2964A)] in connection with IgE production; the role of IL-10 (C-627A) as a regulatory cytokine of allergy; and the severity of food allergy (FA) and atopic eczema (AE) in 220 Japanese allergic children. In addition to these SNPs, environmental factors, i.e., patient's attitude, indoor environment, and so on, were also investigated in this study. Our study was retrospective, and the correlation was analyzed by our defined clinical scores divided into three terms: worst symptoms, recent symptoms and general amelioration at the most recent examination during the disease course. Our results indicated that IL-10 AA, the genotype with lower IL-10 production, is associated with higher IgE levels in the serum (p < 0.0001, estimate; 0.912). Marginal liver abnormalities were observed in the subject group with both FA and AE (p < 0.1191, estimate; 0.1490). Our defined clinical scores enabled evaluation of various aspects of disease severity. Based on the scores, while no single SNP selected in this study determined severity, the combination of the SNP with laboratory data and environmental factors appeared to determine severity.

Adolescent↗
PubMed2006

Comparison of serum high-molecular weight (HMW) adiponectin with total adiponectin concentrations in type 2 diabetic patients with coronary artery disease using a novel enzyme-linked immunosorbent assay to detect HMW adiponectin.

Adiponectin (Acrp30), an adipocyte-derived protein, exists in serum as a trimer, a hexamer, and a high-molecular weight (HMW) form, including 12-18 subunits. Because HMW adiponectin may be biologically active, we measured it in serum using a novel enzyme-linked immunosorbent assay (ELISA) confirmed by gel filtration chromatography that the ELISA detected mainly adiponectin with 12-18 subunits, and we compared HMW with total adiponectin concentration in patients with type 2 diabetes. We next investigated the relationship between serum HMW and coronary artery disease (CAD) in 280 consecutive type 2 diabetic patients, including 59 patients with angiographically confirmed CAD. Total adiponectin was measured in serum by a commercially available ELISA. Like serum total adiponectin, HMW adiponectin correlated positively with HDL cholesterol and negatively with triglyceride, insulin sensitivity, creatinine clearance, and circulating inflammatory markers. Total and HMW adiponectin were significantly higher in women than in men, as was the HMW-to-total adiponectin ratio. Serum HMW and the HMW-to-total adiponectin ratio were significantly lower in men with than without CAD (P < 0.05, respectively). In women, the ratio, but neither total nor HMW adiponectin, tended to be lower when CAD was present. In conclusion, determination of HMW adiponectin, especially relative to total serum adiponectin, is useful for evaluating CAD in type 2 diabetic patients.

Adiponectin↗
PubMed2006

Investigation of false-positive reactions for CBH351 maize in screening PCR analysis.

Examination for CBH351 maize was conducted by the qualitative polymerase chain reaction (PCR) method in maize grain and maize processed foods obtained in the Tokyo area. The numbers of samples possibly positive in the screening test were 7 of 22 (31.8%) for maize grain samples, 4 of 14 (28.6%) for semi-processed foods, 11 of 30 (36.7%) for canned products, 3 of 30 (10.0%) for maize snacks, 3 of 4 (75%) for tacos and 1 of 3 (33.3%) for tortillas. However, CBH351 maize was not detected in the confirmation test. Therefore, the results of the screening test were false-positive. Since the reaction might have been caused by the base sequences of the 3'-end of primers CaM03-5' and CBH02-3' used in the screening test, a new primer pair was designed. The PCR products obtained with the new primer pair TMC2-5'--TMS2-3' were specific for CBH351 and were not obtained with barley, wheat, rice, RRS, Bt11, or Event176. Thus, the new primer pair shows high specificity. CBH351 maize was detected from samples containing at least 0.05% CBH 351 maize DNA by using this primer pair.

Base Sequence↗
PubMed2005

Inhibition by adiponectin of IL-8 production by human macrophages upon coculturing with late apoptotic cells.

Adiponectin, an adipocyte-derived hormone, reportedly suppresses the production of TNF-alpha and IL-6 by LPS-stimulated human or porcine macrophages, and the phagocytosis of microbeads by human macrophages. In this study, we used a high molecular weight form of adiponectin purified from human plasma to examine its effects on the phagocytosis of late apoptotic cells by human macrophages and the subsequent IL-8 production. Adiponectin suppressed both the phagocytosis of apoptotic cells and the IL-8 production. In contrast, adiponectin augmented both the phagocytosis of apoptotic cells and the IL-8 production in the presence of LPS. These results suggest that adiponectin is not an anti-inflammatory hormone but rather a dual modulator of innate responses.

Adiponectin↗
PubMed2005

Reduction of GTP cyclohydrolase I feedback regulating protein expression by hydrogen peroxide in vascular endothelial cells.

We examined the effect of H(2)O(2) on the expression of GTP cyclohydrolase I (GTPCH) feedback regulating protein (GFRP). Addition of H(2)O(2) to endothelial cells decreased GFRP mRNA levels, in contrast to the increase of tetrahydrobiopterin (BH(4)) content and GTPCH mRNA levels. The inhibitors of nitric oxide (NO) synthase and GTPCH had no influence on the decrease of GFRP mRNA levels in H(2)O(2)-treated cells. It is suggested that H(2)O(2) induces BH(4) synthesis through not only induction of GTPCH but also reduction of GFRP. The decrease of GFRP mRNA level appears to be independent of the produced NO and BH(4).

Animals↗
PubMed2005

Detection of genetically modified organisms in foreign-made processed foods containing corn and potato.

Investigations of the validity of labeling regarding genetically modified (GM) products were conducted using polymerase chain reaction (PCR) methods for foreign-made processed foods made from corn and potato purchased in the Tokyo area and in the USA. Several kinds of GM crops were detected in 12 of 32 samples of processed corn samples. More than two GM events for which safety reviews have been completed in Japan were simultaneously detected in 10 samples. GM events MON810 and Bt11 were most frequently detected in the samples by qualitative PCR methods. MON810 was detected in 11 of the 12 samples, and Bt11 was detected in 6 of the 12 samples. In addition, Roundup Ready soy was detected in one of the 12 samples. On the other hand, CBH351, for which the safety assessment was withdrawn in Japan, was not detected in any of the 12 samples. A trial quantitative analysis was performed on six of the GM maize qualitatively positive samples. The estimated amounts of GM maize in these samples ranged from 0.2 to 2.8%, except for one sample, which contained 24.1%. For this sample, the total amount found by event-specific quantitative analysis was 23.8%. Additionally, Roundup Ready soy was detected in one sample of 21 potato-processed foods, although GM potatoes were not detected in any sample.

DNA, Plant↗
PubMed2004

[Detection of genetically modified organisms obtained from food samples ].

Genetially modified organisms (GMOs) were explored in food samples obtained from November 2000 to March 2003 in the Tokyo area by using PCR and real-time PCR techniques. The existence of Roundup Ready Soybean (RRS) was surveyed in processed foods derived from soybeans, such as tofu, boiled soybean, kinako, nama-age, abura-age, natto, miso, soymilk and yuba. RRS was detected in 3 of 37 tofu, 2 of 3 nama-age, 2 of 3 yuba and 3 of 3 abura-age samples. The CBH351 in 70 processed corn foods, NewLeaf Plus and NewLeaf Y in 50 processed potato foods, and 55-1 papaya in 16 papayas were surveyed. These GMOs were not detected among the samples. Qualitative and quantitative analyses of RRS and genetically modified (GM) corn were performed in soybean, corn and semi-processed corn products such as corn meal, corn flour and corn grits. RRS was detected in 42 of 178 soybean samples, and the amount of RRS in RRS-positive samples was determined. The content was in the range of 0.1-1.4% in identity-preserved soybeans (non-GMO), and 49.8-78.8% in non-segregated soybeans. On the other hand, GM corns were detected in 8 of 26 samples. The amount of GM corn in GM corn-positive samples was in the range of 0.1-2.0%.

Carica↗
PubMed2002

Edarabone scavenges nitric oxide.

Oxygen free radicals have been proposed to be major causative agents in secondary brain damage in traumatic and ischemic brain injury. Edarabone (3-methyl-1-phenyl-2-pyrazolin-5-one), a powerful antioxidative radical scavenger, is the only drug currently available in clinical practice for the treatment of cerebral infarction. There has been increasing interest in the role of nitric oxide (NO(*)) as a causative agent in brain injury. In the present study, we investigated the scavenging effect of Edarabone on nitric oxide (NO(*)), using an electron spin resonance (ESR) method. NO(*) was generated from 1-hydroxy-2-oxo-3-(N-3-methyl-3-aminopropyl)-3-methyl-1-triazene (NOC-7), and analyzed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxy (carboxy-PTI) produced from the reaction between 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (carboxy-PTIO) and NO(*). Edarabone directly scavenged NO(*) in a dose-dependent manner. These ESR studies indicate that Edarabone has a direct NO(*) scavenging activity and the additional possibility of novel neuroprotective activities against brain injury and focal cerebral ischemia.

Antioxidants↗
PubMed2002

Free radical scavenging activity of propolis.

We investigated the radical scavenging activity of propolis by ESR spectroscopy using spin trapping method. In addition, we examined the influence of a diet of 2% propolis on mice under oxidative stress. At low concentrations, the methanolic extract of propolis exhibited strong scavenging activity in vitro towards both the superoxide anion radical, generated by the hypoxanthine-xanthine oxidase reaction, and the NO radical, generated from the mixture of NOC-7 (NO generator) and carboxy-PTIO (spin trapping agent). An inhibitory effect of propolis on lipid peroxidation in vivo was observed, as determined by measurement of thiobarbituric acid-reactive substances in mouse liver homogenate. The level of vitamin C in the brain of mice under oxidative stress significantly increased compared with control mice under atmosphere, which was not observed in the mice given 2% propolis. The level of alpha-tocopherol in the brain of mice given 2% propolis significantly increased compared with control mice under atmosphere, which was not observed in mice under oxidative stress. SOD activity in the brain and plasma of mice given 2% propolis significantly decreased under atmosphere and oxidative stress compared with control mice. These results suggest that propolis possesses potent antioxidant activity in vitro and in vivo.

Animals↗
PubMed2002

Evaluation of oxidative damage in the liver of selenium-deficient rats.

Previous studies have implied a relationship between Se-deficiency and oxidative stress. In the present study, the occurrence of oxidative stress due to Se-deficiency was investigated by evaluating the age dependence of growth and indices of oxidative damage for the liver of Se-deficient (SeD) rats. The ratios of liver weight to body weight of the SeD rats were greater than those of the normal rats. The values of AST and ALT (clinical indices of liver damage) were higher in the SeD rats than the normal ones especially in the young (6-12 weeks of age). The TBARS level of the 4-week-old SeD group were higher than the normal group while the level decreased with age. Conversely, the TBARS level of the normal group gradually increased and became higher than SeD group in older rats (12-20 weeks of age). Vitamin E rather than vitamin C may be consumed during oxidative stress due to Se-deficiency. Damage induced by Se-deficiency may be related to growth and the mechanisms of this damage may alter with age.

Age Factors↗
PubMed2002

Induction of CD4+ regulatory T cells by TPA in mice: contra-suppression by CD8+ T cells.

Among the eight inbred mouse strains employed in our preceding report, 12-O-tetradecanoylphorbol 13-acetate (TPA) painting alone induced CD4+ regulatory T (Tr) cells in four strains (e.g., C3H/He) at 6-8 weeks of age, but not in the remaining strains (e.g., C57BL/6, BALB/c). In the present study, the effect of growth from 4-14 weeks on delayed-type hypersensitivity (DTH) response was investigated in three inbred murine strains, C3H/He (H-2k), C57BL/6 (H-2b) and BALB/c (H-2d) mice. In all strains older than 10 weeks, DTH response was suppressed exclusively by TPA painting. The defect of suppressive activity for DTH in several of the strains at 6-8 weeks of age was dependent on the presence of cells, which blocked regulatory cell activity at 6-8 weeks of age, but not at 10 weeks of age. The age-dependent difference in regulatory activity was caused by the presence of CD8+ contra-regulatory T (Tcr) cells. CD8+ contra-regulatory T cells are required to contact regulatory cells in order to block DTH suppressive activity. Adhesion molecules were of great importance in contra-suppression, as antibody treatment to LFA-1 or ICAM-1 blocked this activity. ICAM-1 expression on CD4 T cells greatly increased following growth in 10 week-BALB/c mice receiving TPA than 6-week-old mice, however, a slight increase in growth occurred in 6-to-10-week-old animals in which TPA was absent. The degree of increment in body weight was very similar in these inbred strains. Thymus involution in C3H/He mice was the earliest signal among these mice. This result may suggest that the period of differentiation and maturation of T cells in a first lymphoid tissue for the growth process differs in these three inbred strains. This study provides an interesting example of genetic control of maturation or proliferation of peripheral T cells.

Animals↗
PubMedDate not supplied

Cytotoxic and radical scavenging activity of blended herbal extracts.

Chinese medicines have been applied to a variety of diseases producing various favorable effects, possibly due to the interactions between individual components. Establishment of an evaluation method for such interactions may facilitate the production of new natural medicines. We investigated here the interaction of the hot water extract of Aconiti Tuber (one of the most prominent Chinese medicines) and that of Scutellariae Radix, Coptidis Rhizoma, Glycyrrhizae Radix, Atractylodesi, Lanceae Rhizoma or Poria, by measuring the superoxide anion (O2-), hydroxyl radical (OH) and nitric oxide (NO) scavenging activity, using ESR spectroscopy. We found that a 1:1 mixture of the hot water extract of one herb and that of another herb (referred to as a combined formula) showed a higher radical scavenging activity and cytotoxic activity than the hot water extract of a 1:1 mixture of two herbs (referred to as a blended formula). Both formulae showed higher cytotoxic activity against human oral tumor cell lines than against normal cells. These data further confirm the medicinal usefulness of combinations of empirical Chinese medicines.

CD4-Positive T-Lymphocytes↗
PubMedDate not supplied

Inhibition of LPS-stimulated NO production in mouse macrophage-like cells by Barbados cherry, a fruit of Malpighia emarginata DC.

The extract of Barbados cherry (acerola fruit), a fruit of Malpighia emarginata DC., has been reported to display diverse biological activities such as prevention of age-related diseases. We investigated here the possible effect of Barbados cherry extract on nitric oxide (NO) production by activated macrophages. Barbados cherry was roughly separated into 4 or 5 fractions by two different methods, using various organic solvents such as hexane, acetone, methanol (70% and 100%) and water, and assayed for its ability to inhibit NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like Raw 264.7 cells. Among these fractions, AcOEt extracts (AE0) in Method I and acetone extract (A0) in Method II showed the highest inhibitory activity of NO production (SI > 20 and SI = 31, respectively). When these fractions were subjected to silica gel column chromatography, higher inhibitory activity for NO production was concentrated in AcOEt (AE6) (SI = 64) and benzene-AcOEt (1:4) (A10) fractions (SI > 59). Western blot analysis demonstrated that AE6 and A10 fractions reduced the intracellular concentration of inducible NO synthase (iNOS) by approximately one-third. ESR spectroscopy showed that these fractions scavenged various radical species such as superoxide anion (O2-) and NO radicals. These data suggest that the inhibitory effect on NO production by Barbados cherry extracts is partly due to the inhibition of iNOS expression, and scavenging of O2- and NO radicals.

Animals↗