Defining a longitudinal survival model to examine forced treadmill running as a countermeasure for diet-induced weight gain.

Diet-induced weight gain increases disease risk via disruption of the innate immune system. Flow cytometry is commonly used to assess the immune system; however, in mice such measurements traditionally require terminal procedures and tissue collection to generate sufficient sample. The present study refined an existing flow cytometry method to reduce the number of mice needed to longitudinally measure monocytes. CD-1 male mice were randomly assigned to one of the three groups: DS (diet-induced weight gain + sedentary), DE (diet-induced weight gain + forced treadmill running [total distance 35,755 ± 1832 m]) or NS (normal weight gain + sedentary). DS and DE consumed a 60% fat diet and NS consumed a 10% fat diet ad libitum. Saphenous vein blood samples were collected weekly for a period of six weeks and three-colour flow cytometry was used to measure changes in monocyte (CD11b(+)/14(+)) concentration and cell-surface toll-like receptor 4 (TLR4) expression. DS (18%) and DE (17%) gained more weight than NS (P < 0.001). On a group basis, DS expressed 17% more TLR4 than DE and NS (P = 0.005). The present study demonstrates that a longitudinal survival model can be used to reduce the number of animals needed to complete flow cytometry experiments. Exercise during diet-induced weight prevented some (decreased monocyte TLR4 expression) but not all aspects of innate immune system function.

The reemergence of the trampoline as a recreational activity and competitive sport.

The recreational use of trampolines is widespread and growing rapidly around the world. The reported incidence of significant injuries continues to increase despite more than three decades of attempts to educate the public on the inherent dangers of trampolines and appropriate safety rules for their use. Competitive trampolining also is growing, although there is scant medical literature related to training issues and injuries to assist the physician in guiding and treating these athletes. It is anticipated that with the increased use of trampolines and with the evolution of ever more complex competitive techniques and routines, the potential for catastrophic injuries in competition will increase. This article discusses awareness of the risks and attempts to mitigate injuries. It remains unclear, from an injury risk standpoint, whether trampolines can be used with an acceptable degree of safety.