Dose-response relationship between sports activity and musculoskeletal pain in adolescents.

Physical activity has multiple health benefits but may also increase the risk of developing musculoskeletal pain (MSP). However, the relationship between physical activity and MSP has not been well characterized. This study examined the dose-response relationship between sports activity and MSP among adolescents. Two school-based serial surveys were conducted 1 year apart in adolescents aged 12 to 18 years in Unnan, Japan. Self-administered questionnaires were completed by 2403 students. Associations between time spent in organized sports activity and MSP were analyzed cross-sectionally (n = 2403) and longitudinally (n = 374, students free of pain and in seventh or 10th grade at baseline) with repeated-measures Poisson regression and restricted cubic splines, with adjustment for potential confounders. The prevalence of overall pain, defined as having pain recently at least several times a week in at least one part of the body, was 27.4%. In the cross-sectional analysis, sports activity was significantly associated with pain prevalence. Each additional 1 h/wk of sports activity was associated with a 3% higher probability of having pain (prevalence ratio = 1.03, 95% confidence interval = 1.02-1.04). Similar trends were found across causes (traumatic and nontraumatic pain) and anatomic locations (upper limbs, lower back, and lower limbs). In longitudinal analysis, the risk ratio for developing pain at 1-year follow-up per 1 h/wk increase in baseline sports activity was 1.03 (95% confidence interval = 1.02-1.05). Spline models indicated a linear association (P < 0.001) but not a nonlinear association (P ≥ 0.45). The more the adolescents played sports, the more likely they were to have and develop pain.This study was supported by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. MK is supported by a JSPS Postdoctoral Fellowship for Research Abroad. FI is supported by the Medical Research Council Epidemiology Unit (MC_UU_12015/1; MC_UU_12015/5).This is the final version of the article. It first appeared from Wolters Kluwer via http://dx.doi.org/10.1097/j.pain.000000000000052

PORCN moonlights in a wnt-independent pathway that regulates cancer cell proliferation

10.1371/journal.pone.0034532PLoS ONE74

A liver-derived secretory protein, selenoprotein P, causes insulin resistance

金沢大学医薬保健研究域医学系The liver may regulate glucose homeostasis by modulating the sensitivity/resistance of peripheral tissues to insulin, by way of the production of secretory proteins, termed hepatokines. Here, we demonstrate that selenoprotein P (SeP), a liver-derived secretory protein, causes insulin resistance. Using serial analysis of gene expression (SAGE) and DNA chip methods, we found that hepatic SeP mRNA levels correlated with insulin resistance in humans. Administration of purified SeP impaired insulin signaling and dysregulated glucose metabolism in both hepatocytes and myocytes. Conversely, both genetic deletion and RNA interference-mediated knockdown of SeP improved systemic insulin sensitivity and glucose tolerance in mice. The metabolic actions of SeP were mediated, at least partly, by inactivation of adenosine monophosphate-activated protein kinase (AMPK). In summary, these results demonstrate a role of SeP in the regulation of glucose metabolism and insulin sensitivity and suggest that SeP may be a therapeutic target for type 2 diabetes. © 2010 Elsevier Inc

Stress Relaxation Measurement of Fibroblast Cells with Atomic Force Microscopy

We measured the stress relaxation of mouse fibroblast NIH3T3 cells with an atomic force microscope (AFM) using a sharp silicon tip and a silica bead with a radius of ∼1 µm as an indenter. The decay of loading force was clearly observed in NIH3T3 cells at a small initial loading force of ∼0.4 nN and was well fitted to the stretched exponential function rather than to a single exponential function. The stretching exponent parameter was ∼0.5 for both indenters, indicating that the stress relaxation observed in NIH3T3 cells consisted of multiple relaxation processes. The time-domain AFM technique described in this report allows us to measure directly the relaxation process of living cells in a range from milliseconds to seconds