Enhancement by streptozotocin of O−2 radical generation by the xanthine oxidase system of pancreatic β-cells

AbstractSpin-trapping techniques and electron spin resonance (ESR) spectroscopy were used to study the relationship between the effect of streptozotocin (STZ) on pancreatic β-cells and free radical formation by these cells. Results showed that STZ enhanced generation of the DMPO-OH radical adduct, which is a degradation product of the superoxide anion (O−2) in the presence of cellular components, in a hypoxanthine-xanthine oxidase (XOD) system with a homogenate of β-cells. This enhancing effect was also observed in a system without cellular components; STZ increased the signal height due to the O−2 radical in a concentration-dependent manner and caused a maximum of 150% enhancement at a concentration of 1.5 mM. Thus, STZ seemed to enhance the generation of the O−2 radical in the XOD system, probably by some mechanism of its interaction with XOD. Pancreatic β-cells exhibited a high XOD activity and a very low superoxide dismutase activity. Therefore, the present result supports the possibility that the cytotoxic effect of STZ is closely related to free radical generation in pancreatic β-cells

Comparison of Bacterial Flora in a Methane Fermentation Plant in Field Science Center at Tohoku University and Bovine Rumen Used as the Plant Microbial Resource by 16S rRNA Gene Sequencing

Poster Sessio

Collaborative roles of Temporoparietal Junction and Dorsolateral Prefrontal Cortex in Different Types of Behavioural Flexibility

Behavioural flexibility is essential for everyday life. This involves shifting attention between different perspectives. Previous studies suggest that flexibility is mainly subserved by the dorsolateral prefrontal cortex (DLPFC). However, although rarely emphasized, the temporoparietal junction (TPJ) is frequently recruited during flexible behaviour. A crucial question is whether TPJ plays a role in different types of flexibility, compared to its limited role in perceptual flexibility. We hypothesized that TPJ activity during diverse flexibility tasks plays a common role in stimulus-driven attention-shifting, thereby contributing to different types of flexibility, and thus the collaboration between DLPFC and TPJ might serve as a more appropriate mechanism than DLPFC alone. We used fMRI to measure DLPFC/TPJ activity recruited during moral flexibility, and examined its effect on other domains of flexibility (economic/perceptual). Here, we show the additional, yet crucial role of TPJ: a combined DLPFC/TPJ activity predicted flexibility, regardless of domain. Different types of flexibility might rely on more basic attention-shifting, which highlights the behavioural significance of alternatives.Peer reviewe

Capsaicin inhibits the production of tumor necrosis factor α by LPS-stimulated murine macrophages, RAW 264.7: a PPARγ ligand-like action as a novel mechanism

AbstractCapsaicin, a major ingredient of hot pepper, is considered to exhibit anti-inflammatory properties. Our previous study demonstrated that capsaicin inhibited the production of pro-inflammatory mediators through NF-κB inactivation in LPS-stimulated macrophages. In order to further clarify the mechanism underlying the anti-inflammatory action of capsaicin, we investigated whether capsaicin alters PPARγ activity, which regulates the production of the pro-inflammatory cytokine TNFα. Capsaicin significantly inhibited the production of TNFα by macrophages in a dose-dependent manner. Simultaneous exposure of the cells to capsaicin and PPARγ agonist troglitazone or RXR agonist LG100268 resulted in stronger inhibition of TNFα production compared to the cells treated with either capsaicin, troglitazone, or LG100268 alone. Luciferase reporter assay revealed that capsaicin induced GAL4/PPARγ chimera and full length PPARγ (PPRE) transactivations in a dose-dependent manner. Furthermore, a specific PPARγ antagonist T0070907 abrogated the inhibitory action of capsaicin on LPS-induced TNFα production by RAW 264.7 cells, indicating that capsaicin acts like a ligand for PPARγ. Our data demonstrate for the first time that the anti-inflammatory action of capsaicin may be mediated by PPARγ activation in LPS-stimulated RAW 264.7 cells

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Amorphous carbon is made from organic high polymer by the choise of suitable baking condition and atmospher gasses in the baking oben. In the 500℃ baking, organic high polymer shrink itself, and then it set up shrinkage about 25% in bolume in the 1000℃ baking. Baked organic high polymer in the 200℃ has phisical properties as high polymer, but in the 500℃ baking it has the property of carbon, and then in the 1000℃ up baking it has the phisical property of pure carbon. These properties clarified by the IR spectroanalysis. In the 1000℃ up baking it is gorwing up [002] plane, and shows 0.245 nm layers in the molecular structure. These properties clarified by the X-Ray diffraction analysis. And then, in the 2000℃ baking it shows many 0.245 nm layers in its moleculer structure and it is clarified that it grows up as the tape layer by the high power and high resolution electronic microscopic examinations