Akifumi Kuwabara

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We examined the actions of sphingosine 1-phosphate (S1P) on signaling pathways in Chinese hamster ovary cells transfected with putative S1P receptor subtypes, i.e. Edg-1, AGR16/H218 (Edg-5), and Edg-3. Among these receptor-transfected cells, there was no significant difference in the expressing numbers of the S1P receptors and their affinities to S1P, which(More)
The concentration of sphingosine 1-phosphate (S1P) in plasma or serum is much higher than the half-maximal concentration of the sphingolipid needed to stimulate its receptors. Nevertheless, the inositol phosphate response to plasma or serum mediated by Edg-3, one of the S1P receptors, which was overexpressed in Chinese hamster ovary cells, was much smaller(More)
Sphingosine 1-phosphate (S1P), a novel lipid mediator, is concentrated in the fraction of lipoproteins that include high density lipoprotein (HDL) and low density lipoprotein (LDL) in human plasma. Here, we show that oxidation of LDL resulted in a marked reduction in the S1P level in association with a marked accumulation of lysophosphatidylcholine (LPC).(More)
Sphingosine 1-phosphate (S1P) stimulates thymidine incorporation (DNA synthesis), cell growth and cell migration in human aortic endothelial cells (HAECs). The extent of the S1P-induced responses are comparable to those stimulated by vascular endothelial growth factor, one of the most potent stimulators of angiogenesis. These responses to S1P were mimicked(More)
Exogenous sphingosine 1-phosphate (S1P) increased cytosolic Ca(2+) concentration, stimulated thymidine incorporation (DNA synthesis) and inhibited cell migration in rat aortic smooth-muscle cells (AoSMCs). Although exogenous sphingosine, a substrate of sphingosine kinase or a precursor of S1P, markedly induced the intracellular accumulation of S1P, the(More)
We measured urinary albumin (U-Alb) and type IV collagen (uIV.C) in spot urine collected from 82 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 205 controls. Eighty-two NIDDM patients that had no increased excretion of either U-Alb or uIV.C were observed for 6 months. Prevalence of increased excretion of U-Alb and uIV.C at 6 months in(More)
Tumor necrosis factor-alpha (TNF-alpha) has been suggested to be related to the pathogenesis of autoimmune thyroid diseases, nonthyroid illness, and other thyroid dysfunctions induced by infectious diseases. In relation to these, in vitro studies demonstrated that TNF-alpha influences growth and/or differentiated functions mediated by thyroid-stimulating(More)
We examined the mechanism of action of lysophosphatidylcholine (LPC), which is suggested to be involved in the pathogenesis of atherosclerosis and inflammatory disorders, in HL-60 leukaemia cells. Extracellular 1-palmitoyl LPC increased the intracellular Ca2+ concentration in association with production of inositol phosphate. These actions of LPC were(More)
In this study we aimed to identify clinically relevant patterns of cytomegalovirus (CMV) infection in inflammatory bowel disease. Twenty-two patients with severe ulcerative colitis (UC), 12 with moderate UC, and 16 with Crohn's disease were studied retrospectively. We confirmed CMV infection immunohistochemically. The patients were classified into three(More)
OBJECTIVE In patients with acute myocardial infarction (AMI), low triiodothyronine (T(3)) levels with normal or subnormal levels of thyrotropin (TSH), the euthyroid sick syndrome (ESS), have been reported, however, the mechanism of altered thyroid hormone metabolism is unknown. Recent reports have shown that interleukin-6 (IL-6) plays a key role in the(More)