Osaka University

About: Osaka University is a education organization based out in Osaka, Japan. It is known for research contribution in the topics: Laser & Catalysis. The organization has 83778 authors who have published 185669 publications receiving 5158122 citations. The organization is also known as: Ōsaka daigaku.

IgG1 plasmacytosis in interleukin 6 transgenic mice

Abstract: Interleukin 6 (IL-6) has been suggested to be involved in the pathogenesis of polyclonal and monoclonal plasma cell abnormalities. To address this possibility, transgenic mice carrying the human IL-6 genomic gene fused with a human immunoglobulin heavy chain enhancer were generated. High concentrations of human IL-6 and polyclonal increase in IgG1 (120- to 400-fold) in sera of all transgenic mice were observed. A massive plasmacytosis in thymus, lymph node, and spleen and an infiltration of plasma cells in lung, liver, and kidney were observed. However, the plasma cells were not transplantable to syngeneic mice and were found not to contain chromosomal aberrations including c-myc gene rearrangements. The evidence indicates that deregulated gene expression of IL-6 can trigger polyclonal plasmacytosis but cannot induce plasmacytoma. It is suggested that additional genetic changes may be required for the generation of plasma cell neoplasia. Other interesting findings in these transgenic mice were the development of mesangio-proliferative glomerulonephritis and an increase in megakaryocytes in bone marrow.

Association of Hypoadiponectinemia With Impaired Vasoreactivity

Abstract: Endothelial dysfunction is a crucial feature in the evolution of atherosclerosis. Adiponectin is an adipocyte-specific plasma protein with antiatherogenic and antidiabetic properties. In the present study, we investigated the relation between adiponectin and endothelium-dependent vasodilation. We analyzed endothelial function in 202 hypertensive patients, including those who were not taking any medication. Forearm blood flow was measured by strain-gauge plethysmography. Plasma adiponectin level was highly correlated with the vasodilator response to reactive hyperemia in the total (r=0.257, P<0.001) and no-medication (r=0.296, P=0.026) groups but not with nitroglycerin-induced hyperemia, indicating that adiponectin affected endothelium-dependent vasodilation. Multiple regression analysis of data from all hypertensive patients revealed that plasma adiponectin level was independently correlated with the vasodilator response to reactive hyperemia. Vascular reactivity was also analyzed in aortic rings from adiponectin-knockout (KO) and wild-type (WT) mice. Adiponectin-KO mice showed obesity, hyperglycemia, and hypertension compared with WT mice after 4 weeks on an atherogenic diet. Endothelium-dependent vasodilation in response to acetylcholine was significantly reduced in adiponectin-KO mice compared with WT mice, although no significant difference was observed in endothelium-independent vasodilation in response to sodium nitroprusside. Our observations suggest that hypoadiponectinemia is associated with impaired endothelium-dependent vasorelaxation and that the measurement of plasma adiponectin level might be helpful as a marker of endothelial dysfunction.

Functional analysis of AHK1/ATHK1 and cytokinin receptor histidine kinases in response to abscisic acid, drought, and salt stress in Arabidopsis

Abstract: In plants, multistep component systems play important roles in signal transduction in response to environmental stimuli and plant growth regulators. Arabidopsis contains six nonethylene receptor histidine kinases, and, among them, AHK1/ATHK1, AHK2, AHK3, and CRE1 were shown to be stress-responsive, suggesting their roles in the regulation of plant response to abiotic stress. Gain- and loss-of-function studies in Arabidopsis indicated that AHK1 is a positive regulator of drought and salt stress responses and abscisic acid (ABA) signaling. Microarray analysis of the ahk1 mutant revealed a down-regulation of many stress- and/or ABA-inducible genes, including AREB1, ANAC, and DREB2A transcription factors and their downstream genes. These data suggest that AHK1 functions upstream of AREB1, ANAC, and DREB2A and positively controls stress responses through both ABA-dependent and ABA-independent signaling pathways. In addition, AHK1 plays important roles in plant growth because the ahk1 ahk2 ahk3 triple mutant showed further reduced growth. Unlike AHK1, loss-of-function analysis of ahk2, ahk3, and cre1 implied that the stress-responsive AHK2, AHK3, and CRE1 act as negative regulators in ABA signaling. AHK2 and AHK3 also negatively control osmotic stress responses in Arabidopsis because ahk2, ahk3, and ahk2 ahk3 mutants were strongly tolerant to drought and salt stress due to up-regulation of many stress- and/or ABA-inducible genes. Last, cytokinin clearly mediates stress responses because it was required for CRE1 to function as a negative regulator of osmotic stress.

Gravity in the Randall-Sundrum Brane World

Abstract: We discuss the weak gravitational field created by isolated matter sources in the Randall-Sundrum brane world For the case of a single wall of positive tension, the field stays localized near the wall if the source is stationary We calculate the leading Kaluza-Klein corrections to the linearized gravitational field of a nonrelativistic spherical object, which is different from the Schwarzschild solution at large distances In the case of two branes of opposite tension, linearized Brans-Dicke (BD) gravity is recovered on either wall, with different BD parameters On the wall with positive tension the BD parameter is larger than 3000 provided that the separation between walls is larger than 4 times the AdS radius The gravitational field due to shadow matter is also considered