In vitro and in vivo assessment of extended duration cathodic voltage-controlled electrical stimulation for treatment of orthopedic implant-associated infections.

Effective treatment of orthopedic implant-associated infections (IAIs) remains a clinical challenge. The in vitro and in vivo studies presented herein evaluated the antimicrobial effects of applying cathodic voltage-controlled electrical stimulation (CVCES) to titanium implants inoculated with preformed bacterial biofilms of methicillin-resistant Staphylococcus aureus (MRSA). The in vitro studies showed that combining vancomycin therapy (500 µg/mL) with application of CVCES at -1.75 V (all voltages are with respect to Ag/AgCl unless otherwise stated) for 24 h resulted in 99.98% reduction in the coupon-associated MRSA colony-forming units (CFUs) (3.38 × 103 vs. 2.14 × 107 CFU/mL, p < 0.001) and a 99.97% reduction in the planktonic CFU (4.04 × 104 vs. 1.26 × 108 CFU/mL, p < 0.001) as compared with the no treatment control samples. The in vivo studies utilized a rodent model of MRSA IAIs and showed a combination of vancomycin therapy (150 mg/kg twice daily) with CVCES of -1.75 V for 24 h had significant reductions in the implant associated CFU (1.42 × 101 vs. 1.2 × 106 CFU/mL, p < 0.003) and bone CFU (5.29 × 101 vs. 4.48 × 106 CFU/mL, p < 0.003) as compared with the untreated control animals. Importantly, the combined 24 h CVCES and antibiotic treatments resulted in no implant-associated MRSA CFU enumerated in 83% of the animals (five out of six animals) and no bone-associated MRSA CFU enumerated in 50% of the animals (three out of six animals). Overall, the outcomes of this study have shown that extended duration CVCES therapy is an effective adjunctive therapy to eradicate IAIs.

Effects of arm weight and target height on hand selection: A low-cost virtual reality paradigm.

We evaluated the ability of a virtual reality (VR) system to reliably detect the reaching frequency midline position of a user; the distinguishing plane between free-choice use of the left and right hand. The paradigm utilized the Leap Motion Hand Tracker along with a custom script written in C# and was realized through a Unity3D application. Stimuli appeared in random locations on the computer screen and required the participant to reach with the hand of their choice to contact them with a virtually coupled hand inside the virtual space. We investigated the effects of two manipulations of effort on the free-choice reaching of either the left or right hand. We varied the height of target positions and applied an additional weight to the non-dominant, left hand. We observed main effects of height and weight on reaching frequency midline positions across the group. We found increased use of the dominant hand as stimuli height increased, as well as a significant increase in overall use of the dominant, right hand when a weighted-glove was worn by the non-dominant, left hand. Our results are in line with previously published research on hand selection from similar paradigms, supporting the use of our VR paradigm in future experiments and applications.