Bactericidal and cytotoxic effects of chloramine-T on wound pathogens and human fibroblasts in vitro.

OBJECTIVES: To evaluate cytotoxicity and bactericidal effects of chloramine-T. METHODS: In vitro study of various concentrations and exposure times to preparations containing human fibroblasts or 1.5 x 10 colony forming units per milliliter (CFU/mL) of 3 gram-positive bacteria-Staphylococcus aureus, methicillin-resistant S aureus, and vancomycin-resistant Enterococcus faecalis-and 2 gram-negative bacteria-Escherichia coli and Pseudomonas aeruginosa-with and without fetal bovine serum present. MAIN OUTCOME MEASURES: Percentage reduction of bacterial growth and percentage of viable fibroblasts 48 hours after exposure. RESULTS: All gram-positive growth was reduced by 95% to 100%, regardless of dose, with or without serum. E coli (gram-negative; with/without serum) was reduced 94% to 100% at antiseptic concentrations of 300 and 400 ppm. At 200 ppm, E coli growth was fully inhibited without serum present and by 50% with serum. P aeruginosa (gram-negative) was not significantly affected under any conditions. At 100 and 200 ppm, cell viability remained greater than 90% under all experimental conditions. A 300-ppm, 3-minute exposure to chloramine-T resulted in cell viability of up to 70%, with longer exposures producing lower viabilities. Serum did not affect cell viability in any condition. CONCLUSIONS: In vitro, chloramine-T at 200 ppm for 5 to 20 minutes was effective against 3 virulent gram-positive bacteria without fibroblast damage. At 300 ppm and 3 and 5 minutes, 30% of fibroblasts were damaged and 95% to 100 % of E coli were inhibited, respectively.

Effect of computer keyboard slope on wrist position and forearm electromyography of typists without musculoskeletal disorders.

BACKGROUND AND PURPOSE: Positioning a computer keyboard with a downward slope reduces wrist extension needed to use the keyboard and has been shown to decrease pressure in the carpal tunnel. However, whether a downward slope of the keyboard reduces electromyographic (EMG) activity of the forearm muscles, in particular the wrist extensors, is not known. SUBJECTS AND METHODS: Sixteen experienced typists participated in this study and typed on a conventional keyboard that was placed on slopes at angles of 7.5, 0, -7.5, and -15 degrees. Electromyographic activity of the extensor carpi ulnaris (ECU), flexor carpi ulnaris (FCU), and flexor carpi radialis (FCR) muscles was measured with surface electrodes, while the extension and ulnar deviation angles of the right and left wrists were measured with electrogoniometers. RESULTS: Wrist extension angle decreased from approximately 12 degrees of extension while typing on a keyboard with a 7.5-degree slope to 3 degrees of flexion with the keyboard at a slope of -15 degrees. Although the differences were in the range of 1% to 3% of maximum voluntary contraction (MVC), amplitude probability distribution function (APDF) of root-mean-square EMG data points from the ECU, FCU, and FCR muscles varied across keyboard slopes. DISCUSSION AND CONCLUSION: Wrist extension decreased as the keyboard slope decreased. Furthermore, a slight decrease in percentage of MVC of the ECU muscle was noted as the keyboard slope decreased. Based on biomechanical modeling and published work on carpal tunnel pressure, both of these findings appear to be positive with respect to comfort and fatigue, but the exact consequences of these findings on the reduction or prevention of injuries have yet to be determined. The results may aid physical therapists and ergonomists in their evaluations of computer keyboard workstations and in making recommendations for interventions with regard to keyboard slope angle.

A randomized controlled clinical trial to evaluate the effects of noncontact normothermic wound therapy on chronic full-thickness pressure ulcers.

OBJECTIVE: To determine the effect of noncontact normothermic wound therapy (NNWT) versus standard wound care on chronic full-thickness pressure ulcers. DESIGN: Prospective, randomized, controlled trial. SETTING: Veterans administration medical center and 7 long-term-care facilities. PATIENTS: 40 inpatients with 43 Stage III and IV pressure ulcers. INTERVENTIONS: A sterile noncontact wound dressing was applied to 21 wounds for 24 hours per day, 7 days per week. Each day after the wound was irrigated and the noncontact dressing was changed, a heating element in the dressing was activated for 3 1-hour periods for 12 weeks or until wound closure. Twenty-two control wounds were treated with standard, moisture-retentive dressings 24 hours per day, 7 days per week for 12 weeks or until wound closure. MAIN OUTCOME MEASURE: Measurement of wound surface area. MAIN RESULTS: Healing rate for the NNWT group was significantly greater than for the control group (0.52 cm2 per week and 0.23 cm2 per week, respectively; P<.02). A clinically significant increase was seen among the NNWT group in the incidence of closure among wounds that completed the entire 12-week protocol compared with controls (11 of 14 or 79% and 8 of 16 or 50%, respectively; not significant). The mean slope of the individual regression analyses for the NNWT group was significantly different from the mean slope for the control group (-0.07 and -0.033, respectively; P<.05). Large wounds in the NNWT group demonstrated a significantly greater healing rate than large wounds in the control group (P <.05). CONCLUSION: Wounds treated with NNWT healed significantly faster than wounds in the control group. The healing rate was greatest for larger wounds treated with NNWT.