The embryonic genes Dkk3, Hoxd8, Hoxd9 and Tbx1 identify muscle types in a diet-independent and fiber-type unrelated way

<p>Abstract</p> <p>Background</p> <p>The mouse skeletal muscle is composed of four distinct fiber types that differ in contractile function, number of mitochondria and metabolism. Every muscle type has a specific composition and distribution of the four fiber types. To find novel genes involved in specifying muscle types, we used microarray analysis to compare the gastrocnemius with the quadriceps from mice fed a low fat diet (LFD) or high fat diet (HFD) for 8 weeks. Additional qPCR analysis were performed in the gastrocnemius, quadriceps and soleus muscle from mice fed an LFD or HFD for 20 weeks.</p> <p>Results</p> <p>In mice fed the 8-week LFD 162 genes were differentially expressed in the gastrocnemius <it>vs</it>. the quadriceps. Genes with the strongest differences in expression were markers for oxidative fiber types (e.g. <it>Tnni1</it>) and genes which are known to be involved in embryogenesis (<it>Dkk3</it>, <it>Hoxd8</it>,<it>Hoxd9 </it>and <it>Tbx1</it>). Also <it>Dkk2, Hoxa5, Hoxa10, Hoxc9, Hoxc10, Hoxc6 </it>and <it>Tbx15 </it>were detectably, but not differentially expressed in adult muscle tissue. Expression of differentially expressed genes was not influenced by an 8-week or 20-week HFD. Comparing gastrocnemius, quadriceps and soleus, expression of <it>Hoxd8 </it>and <it>Hoxd9 </it>was not related with expression of markers for the four different fiber types. We found that the expression of both <it>Hoxd8 </it>and <it>Hoxd9 </it>was much higher in the gastrocnemius than in the quadriceps or soleus, whereas the expression of <it>Dkk3 </it>was high in quadriceps, but low in both gastrocnemius and soleus. Finally, expression of <it>Tbx1 </it>was high in quadriceps, intermediate in soleus and low in gastrocnemius.</p> <p>Conclusions</p> <p>We found that genes from the Dkk family, Hox family and Tbx family are detectably expressed in adult mouse muscle. Interestingly, expression of <it>Dkk3</it>, <it>Hoxd8, Hoxd9 </it>and <it>Tbx1 </it>was highly different between gastrocnemius, quadriceps and soleus. In fact, every muscle type showed a unique combination of expression of these four genes which was not influenced by diet. Altogether, we conclude that genes important for embryogenesis identify mouse muscle types in a diet-independent and fiber type-unrelated manner.</p

An online expert network for high quality information on occupational safety and health: cross-sectional study of user satisfaction and impact

<p>Abstract</p> <p>Background</p> <p>Many people have difficulties finding information on health questions, including occupational safety and health (OSH) issues. One solution to alleviate these difficulties could be to offer questioners free-of-charge, online access to a network of OSH experts who provide tailored, high-quality information. The aim of this study was to assess whether network quality, respectively information quality, as perceived by the questioners, is associated with questioners' overall satisfaction and to explore the impact of the information received on questioners' knowledge, work and work functioning.</p> <p>Methods</p> <p>We evaluated the experiences of OSH questioners with the online network ArboAntwoord.com over a two-year period. In this network, approximately 80 qualified experts are available to answer OSH questions. By means of a questionnaire, we assessed questioners' overall satisfaction with the network, whether the network was user-friendly, easily accessible and easy to handle and whether the information provided was complete, applicable and received in a timely manner. The impact of the information on questioners' knowledge, work or work functioning was explored with seven questions. In the study period, 460 unique OSH questioners asked 851 OSH questions. In total, 205 of the 460 questioners completed the questionnaire (response rate 45%).</p> <p>Results</p> <p>Of the responders, 71% were satisfied with the ArboAntwoord network. Multiple logistic regression analysis showed that the applicability of the information had a positive influence on the questioners' overall satisfaction (OR = 16.0, 95% CI: 7.0-36.4). Also, user friendliness of the network (OR = 3.3, 95% CI: 1.3-8.6) and completeness of the information provided (OR = 3.0, 95% CI: 1.3-6.8) were positively related to the questioners' satisfaction. For 74% of the questioners, the information helped to increase their knowledge and understanding. Overall, 25% of the questioners indicated that the received information improved their work, work functioning or health.</p> <p>Conclusions</p> <p>A free-of-charge, online expert network in the field of OSH can be a useful strategy to provide OSH questioners with applicable, complete and timely information that may help improve safety and health at work. This study provides more insight in how to satisfy network questioners and about the potential impact of provided information on OSH.</p