Differing Effects of Nociception and Pain Memory on Isometric Muscle Strength in Participants With and Without a History of Injury: A Quasi-Experimental Study.

OBJECTIVE: The goals of this study are to establish whether mechanical pressure pain, short-term memory recall of a painful stimulus, or long-term memory of a previous painful lower limb injury alters isometric muscle strength and whether there was a difference in responses between participants with and without a previous history of injury. DESIGN: Fifty-nine pain-free participants (29 with previous injury and 30 without) participated in this study. Tibialis anterior isometric muscle strength was compared pre- and post-noxious mechanical stimulus with instructions to recall pain (short- and long-term). RESULTS: Short- and long-term pain recall produced a significant reduction in muscle strength (short-term: F (1,57) = 160.472, P < 0.001; long-term: F (1,57) = 128.899, P < 0.001). A greater decrease was experienced with short- and long-term pain memory than exposure to mechanical pain (mechanical pain: -14.8% or -32.98 kg, 95% confidence interval [CI], -41.57 to -24.19; short-term: -24.1% or -52.70 kg, 95% CI = -60.98 to -44.34; long-term: -20.3% or -44.63 kg, 95% CI = -52.77 to -36.95). There was no significant difference in responses associated with an injury history. CONCLUSIONS: Findings suggest that recalled pain memory can impact motor responses and calls attention to the role of past injury history in the rehabilitation process.

The West Nile virus assembly process evades the conserved antiviral mechanism of the interferon-induced MxA protein.

Flaviviruses have evolved means to evade host innate immune responses. Recent evidence suggests this is due to prevention of interferon production and signaling in flavivirus-infected cells. Here we show that the interferon-induced MxA protein can sequester the West Nile virus strain Kunjin virus (WNVKUN) capsid protein in cytoplasmic tubular structures in an expression-replication system. This sequestering resulted in reduced titers of secreted WNVKUN particles. We show by electron microscopy, tomography and 3D modeling that these cytoplasmic tubular structures form organized bundles. Additionally we show that recombinant ER-targeted MxA can restrict production of infectious WNVKUN under conditions of virus infection. Our results indicate a co-ordinated and compartmentalized WNVKUN assembly process may prevent recognition of viral components by MxA, particularly the capsid protein. This recognition can be exploited if MxA is targeted to intracellular sites of WNVKUN assembly. This results in further understanding of the mechanisms of flavivirus evasion from the immune system.

Efficient automatic noise reduction of electron tomographic reconstructions based on iterative median filtering.

A simple, fast and efficient noise-reduction protocol for three-dimensional electron tomographic reconstructions of biological material is presented. The approach is based on iterative application of median filtering and shows promise for automatic noise reduction as a pre-processor for automated data analysis tools which aim at segmentation, feature extraction and pattern recognition. The application of this algorithm produces encouraging results for a wide variety of experimental and synthetic electron tomographic reconstructions.