21 research outputs found

    Ozone induces glucose intolerance and systemic metabolic effects in young and aged brown Norway rats

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    Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α2-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2> 1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation

    Influence of Visual Feedback on Passive Tactile Perception of Speed and Spacing of Rotating Gratings

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    Abstract. We studied the influence of visual feedback on the tactual perception of both speed and spatial period of a rotating texture. Participants were placed in a situation of perceptual conflict concerning the rotation speed of a cylindrical texture. Participants touched a cylindrical texture of gratings rotating around its axis at a constant speed, while they watched a cylinder without gratings rotating at a different speed on a computer screen. Participants were asked to estimate the speed of the gratings texture under the finger and the spacing (or spatial period) of the gratings. We observed that the tactual estimations of both speed and spacing co-varied with the speed of the visual stimulus, although the cylinder perceived tactually rotated at a constant speed. The first effect (speed effect) could correspond to the resolution of the perceptual conflict in favor of vision. The second effect (spacing effect) is apparently surprising, since no varying information about spacing was provided by vision. However, the physical relation between spacing and speed is well established according to every day experience. Thus, the parameter extraneou
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