Time filter

Source Type

Fukuoka, Japan

University of Occupational and Environmental Health Japan is a private university in Kitakyushu City, Fukuoka Prefecture, Japan, established in 1978. Wikipedia.

Yamazaki F.,University of Occupational and Environmental Health Japan
Journal of Applied Physiology | Year: 2012

Local administration of ascorbic acid (Asc) at a supraphysiological concentration inhibits the cutaneous vasoconstrictor response to local cooling (LC). However, whether orally ingesting Asc inhibits the LC-induced vasoconstrictor response remains unknown. The purpose of the present study was to examine the acute influence of oral Asc on the adrenergic vasoconstrictor response to LC in human skin. In experiment 1, skin blood flow (SkBF) was measured by laser-Doppler flowmetry at three sites (forearm, calf, palm). The three skin sites were locally cooled from 34 to 24°C at -1°C/min and maintained at 24°C for 20 min before (Pre) and 1.5 h after (Post) oral Asc (2-g single dose) or placebo supplementation. Cutaneous vascular conductance (CVC) was calculated as the ratio of SkBF to blood pressure and expressed relative to the baseline value before LC. Oral Asc enhanced (P < 0.05) the reductions in CVC in the forearm (Pre, -50.3 ± 3.3%; Post, -57.8 ± 2.2%), calf (Pre, -52.6 ± 3.7%; Post, -66.1 ± 4.3%), and palm (Pre, -46.2 ± 6.2%; Post, -60.4 ± 5.6%) during LC. The placebo did not change the responses at any site. In experiment 2, to examine whether the increased vasoconstrictor response caused by oral Asc is due to the adrenergic system, the release of neurotransmitters from adrenergic nerves in forearm skin was blocked locally by iontophoresis of bretylium tosylate (BT). Oral Asc enhanced (P < 0.05) the reductions in CVC at untreated control sites but did not change the responses at BT-treated sites during LC. In experiment 3, to further examine whether adrenergically mediated vasoconstriction is enhanced by oral Asc, 0.1 mM tyramine was administered using intradermal microdialysis in the forearm skin at 34°C in the Pre and Post periods. Oral Asc increased (P < 0.05) the tyramine-induced reduction in CVC. These findings suggest that oral Asc acutely enhances the cutaneous vasoconstrictor responses to LC through the modification of adrenergic sympathetic mechanisms. © 2012 the American Physiological Society. Source

Yamazaki F.,University of Occupational and Environmental Health Japan
Journal of Applied Physiology | Year: 2010

Local cooling (LC) of nonlabrous skin causes vasoconstriction via the adrenergic and removal of nitric oxide (NO) systems. Since cooling increases reactive oxygen species in smooth muscle cells and induces increased sensitivity of α-adrenergic receptors, antioxidant supplementation may attenuate the vasoconstrictor response to skin LC via adrenergic and/or NO systems. To test this hypothesis, we examined the effects of acute L-ascorbate (Asc, 10 mM) supplementation in human skin on the vasoconstrictor responses to LC in skin with and without NO synthase (NOS) inhibition or adrenergic receptor blockade. In a three-part study, forearm sites were instrumented with microdialysis fibers, local coolers, and laser-Doppler flow (LDF) probes in healthy volunteers. Sites were cooled from 34 to 24°C at - 1°C/min and maintained at 24° C for 20 min (parts 1 and 2) or 30 min (part 3). During the last 10 min of LC in parts 1 and 2, whole body cooling was performed to increase sympathetic vasoconstrictor activity. Cutaneous vascular conductance (CVC) was calculated as the ratio of LDF to blood pressure and expressed relative to the baseline value before cooling. Treatments in each part were as follows: part 1) untreated, Asc; part 2) NG-nitro-L-arginine methyl ester (L-NAME) to inhibit NOS, combined L-NAME + Asc; part 3) yohimbine (YOH) + propranolol (PRO) to antagonize α- and β-adrenergic receptors and combined YOH + PRO + Asc. CVC reduction during LC was smaller (P < 0.001) at Asc sites (-31 ± 4%) than at untreated sites (-56 ± 5%). LC-induced reduction in CVC was smaller (P < 0.05) at L-NAME + Asc sites (-23 ± 8%) than at L-NAME sites (-43 ± 7%). LCinduced reduction in CVC did not differ between at PRO + YOH sites (-56 ± 3%) and at PRO + YOH + Asc sites (-50 ± 3%). These findings suggest that antioxidant supplementation inhibits the vasoconstrictor response to direct cooling through an adrenoceptor-dependent mechanism in human skin. Copyright © 2010 the American Physiological Society. Source

Tokura Y.,University of Occupational and Environmental Health Japan
Journal of Dermatological Science | Year: 2010

Atopic dermatitis (AD) can be categorized into the extrinsic and intrinsic types. Extrinsic or allergic AD shows high total serum IgE levels and the presence of specific IgE for environmental and food allergens, whereas intrinsic or non-allergic AD exhibits normal total IgE values and the absence of specific IgE. While extrinsic AD is the classical type with high prevalence, the incidence of intrinsic AD is approximately 20% with female predominance. The clinical features of intrinsic AD include relative late onset, milder severity, and Dennie-Morgan folds, but no ichthyosis vulgris or palmar hyperlinearity. The skin barrier is perturbed in the extrinsic, but not intrinsic type. Filaggrin gene mutations are not a feature of intrinsic AD. The intrinsic type is immunologically characterized by the lower expression of interleukin (IL) -4, IL-5, and IL-13, and the higher expression of interferon-γ. It is suggested that intrinsic AD patients are not sensitized with protein allergens, which induce Th2 responses, but with other antigens, and metals might be one of the candidates of such antigens. © 2010 Japanese Society for Investigative Dermatology. Source

Tanaka Y.,University of Occupational and Environmental Health Japan
Current Opinion in Rheumatology | Year: 2012

Purpose of Review: Biologics targeting tumor necrosis factor (TNF) has revolutionized the treatment of rheumatoid arthritis (RA) and clinical remission becomes a realistic treatment goal. After achieving remission, discontinuation of TNF inhibitors may become an important issue from viewing points of safety and economy. However, there is not well established firm evidence regarding biologic-free remission. We here document whether 'treatment holiday' of TNF inhibitors is possible in RA patients, after maintaining low disease activity by intensive treatment with TNF inhibitors. Recent Finding: From European studies such as BeSt and OPTIMA in patients with early RA and Japanese studies such as RRR and HONOR in patients with established RA, after reduction of disease activity to clinical remission or low disease activity in patients with RA by infliximab or adalimumab in combination with methotrexate, some patients could successfully remain in clinical remission without TNF inhibitors for 6 months or 1 year and without radiologic and functional progression of articular destruction. Summary: After maintaining low disease activity by intensive treatment with TNF inhibitors, discontinuation of TNF inhibitors without disease flare, joint damage progression and functional impairment, treatment holiday, is possible in some RA patients. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Nakai H.,University of Occupational and Environmental Health Japan
Circulation journal : official journal of the Japanese Circulation Society | Year: 2012

Different influences of left ventricular (LV) remodeling on anterior and posterior mitral leaflet (AML and PML) tethering in ischemic mitral regurgitation (MR) has not been fully investigated. We hypothesized that progressive outward displacement of papillary muscles, including posterior vector, may cause greater tethering to PML compared to AML. In 79 patients with LV ejection fraction <50% and 20 controls, LV sphericity, AML and PML tethering angles, apical and posterior displacement of coaptation, mitral annular area, and severity of MR (vena contracta width) were measured using 3-D echocardiography. To examine different influences of LV remodeling on AML and PML tethering, interaction between AML/PML and LV sphericity was tested using multiple regression analysis. Both AML and PML tethering significantly increased with increased LV sphericity (r=0.59 and 0.65, P<0.001). Multiple regression yielded a significant interaction term between AML vs. LV sphericity and PML vs. LV sphericity (t=3.69, P<0.001), indicating greater influence from LV remodeling on PML compared to that for the AML. Multivariate analysis demonstrated independent contributions to MR severity from PML tethering primarily along with posterior and apical displacement of coaptation. LV remodeling augments tethering of both AML and PML, with greater influence on PML. Source

Discover hidden collaborations