4,837 research outputs found

    Does Neuromuscular Electrical Stimulation as an Adjunct to Traditional Physical Therapy Improve Post-Operative Mobility After Total Knee Arthroplasty in Comparison to Traditional PT Alone in Patients 50-85 Years Old?

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    OBJECTIVE: The objective of this selective Evidence Based Medicine (EBM) review is to determine whether or not neuromuscular electrical stimulation (NMES) as an adjunct to traditional physical therapy (PT) improves post-operative mobility including walking and stairclimbing ability following total knee arthroplasty (TKA) in comparison to traditional PT alone in patients 50-85 years old. STUDY DESIGN: Review of three English language primary studies published after 1999. DATA SOURCES: Three randomized controlled trials comparing traditional PT with PT and adjuvant NMES following TKA in patients 50-85 years old found using PubMed and EBSCOhost Web. OUTCOMES MEASURED: Clinical outcome was measured in each of the three studies through various assessments of post-operative mobility including a six-minute walk test (6MWT), stair-climbing test (SCT), tug up-and-go test (TUG), and walking distance. Each study assessed post-operative improvement from baseline after the respective intervention was introduced. RESULTS: The study by Petterson et al. revealed no statistically significant difference between interventional and control groups of the RCT cohort, but significant improvements were noted between the RCT and standard of care cohorts. Both RCTs completed by Avramidis et al. and Stevens-Lapsley demonstrated that adjunctive NMES was an effective means to minimize deficits in quadriceps muscle strength and muscle atrophy thereby increasing functional recovery following TKA surgery. CONCLUSION: The results of the RCTs reviewed suggest NMES is an effective adjunct to traditional PT regimens and permits greater gains in muscle strength and attenuates quadriceps muscle atrophy which allows for more significant functional gains in walking and stair-climbing ability following TKA. Further research needs to be completed to assess appropriate duration and intensity of NMES as well as the potential benefit of pre-operative use ofs NMES

    Out-of-sequence signal 3 as a mechanism for virus-induced immune suppression of CD8 T cell responses

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    Virus infections are known to induce a transient state of immune suppression often associated with an inhibition of T cell proliferation in response to mitogen or cognate-antigen stimulation. Recently, virus-induced immune suppression has been linked to responses to type 1 interferon (IFN), a signal 3 cytokine that normally can augment the proliferation and differentiation of T cells exposed to antigen (signal 1) and co-stimulation (signal 2). However, pre-exposure of CD8 T cells to IFN-inducers such as viruses or poly(IratioC) prior to antigen signaling is inhibitory, indicating that the timing of IFN exposure is of essence. We show here that CD8 T cells pretreated with poly(IratioC) down-regulated the IFN receptor, up-regulated suppressor of cytokine signaling 1 (SOCS1), and were refractory to IFNbeta-induced signal transducers and activators of transcription (STAT) phosphorylation. When exposed to a viral infection, these CD8 T cells behaved more like 2-signal than 3-signal T cells, showing defects in short lived effector cell differentiation, reduced effector function, delayed cell division, and reduced levels of survival proteins. This suggests that IFN-pretreated CD8 T cells are unable to receive the positive effects that type 1 IFN provides as a signal 3 cytokine when delivered later in the signaling process. This desensitization mechanism may partially explain why vaccines function poorly in virus-infected individuals

    Properties of a square root transformation regression model

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    We consider the problem of modelling the conditional distribution of a response given a vector of covariates x when the response is a compositional data vector u. That is, u is defined on the unit simplex [...] This definition of the unit simplex differs subtly from that of Aitchison (1982), as we relax the con- dition that the components of u must be strictly positive. Under this scenario, use of the ratio (or logratio) to compare different compositions is not ideal since it is undefined in some instances, and subcompositional analysis is also not appropriate due to the possibility of division by zero. It has long been recognised that the square root transformation [...] transforms compositional data (including zeros) onto the surface of the (p-1)-dimensional hyperspher
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