The impact of first-aid dressing design on healing of porcine partial thickness wounds.

Literature describes that a well-maintained moist wound healing environment leads to faster healing by preventing scabbing and drying of the wound. A moist wound speeds healing by allowing for unimpeded movement of newly dividing epidermal cells in the wound. Contrary to what is described in literature and practiced by clinicians, first-aid dressings used at home by consumers advertise breathability and absorptivity as benefits. This manuscript examines the effects of dressing breathability and highly absorptive pads on healing and wound appearance in a porcine dermatome wound model, designed to mimic an abrasion injury. Partial thickness wounds were covered with an experimental silicone-polymer film dressing and various over-the-counter bandages for time frames ranging from 4 to 11 days. The progression of healing was quantified by histology and wound-size reduction measurements. The thickness and persistence of a scab or serocellular crust (SCC) over the injury was measured using both pixel density and optical coherence tomography to supplement visual observations, demonstrating new tools for quantification of SCC over wounds. The results of the experiments illustrate the impact of dressing features on the rate of wound reepithelialization and the formation of SCC. Both a low moisture vapor transmission rate (MVTR) and the absence of an absorptive layer were important in speeding wound healing. Surprisingly, use of a dressing with a low MVTR and a highly absorptive pad healed significantly more slowly than a comparative dressing with a low MVTR and no absorptive pad, even though both dressings had very little scab formation over the wound. This study shows that breathability and absorbency of dressings play independent roles in providing an optimal healing environment, and that these properties can vary widely among commercially available dressings.

A mucosal model to study microbial biofilm development and anti-biofilm therapeutics.

Biofilms are a sessile colony of bacteria which adhere to and persist on surfaces. The ability of bacteria to form biofilms is considered a virulence factor, and in fact is central to the pathogenesis of some organisms. Biofilms are inherently resistant to chemotherapy and host immune responses. Clinically, biofilms are considered a primary cause of a majority of infections, such as otitis media, pneumonia in cystic fibrosis patients and endocarditis. However, the vast majority of the data on biofilm formation comes from traditional microtiter-based or flow displacement assays with no consideration given to host factors. These assays, which have been a valuable tool in high-throughput screening for biofilm-related factors, do not mimic a host-pathogen interaction and may contribute to an inappropriate estimation of the role of some factors in clinical biofilm formation. We describe the development of a novel ex vivo model of biofilm formation on a mucosal surface by an important mucosal pathogen, methicillin resistant S. aureus (MRSA). This model is being used for the identification of microbial virulence factors important in mucosal biofilm formation and novel anti-biofilm therapies.

Resistance of antimicrobial skin preparations to saline rinse using a seeded bacteria model.

OBJECTIVE: We describe a randomized blinded study to evaluate the antimicrobial persistence following saline exposure of 2 commercially available skin antiseptic agents. One agent contained iodine povacrylex in alcohol and the second contained chlorhexidine gluconate in alcohol. METHOD: Both agents were applied to the forearms of 36 healthy subjects according to manufacturers' instructions and allowed to dry. The sites were then exposed to either a saline rinse or to a saline-saturated gauze, similar to the challenges that preps would face during most surgical procedures. Two analyses were performed: (1) An indicator organism was seeded onto the treated sites. After 30 minutes, samples were collected from the treated sites and surviving bacterial colonies were enumerated and log reductions calculated. (2) The saline-saturated gauze was analyzed chemically for presence of chlorhexidine or iodine. RESULTS: The baseline densities (stated as logarithms of colony forming units "log CFU") of the sites to which the agents were applied had statistically equivalent microbial densities. Both agents reduced the density of organisms in a statistically significant manner. Chemical analysis of the gauze samples indicated that 35 of 36 samples had detectable chlorhexidine while no samples had detectable iodine (P < .0001). CONCLUSION: The results indicate that chlorhexidine is removed by saline-soaked gauze while the iodine povacrylex water-insoluble film remains intact under the same conditions. The implication is that similar results may occur in surgery when saline is used.

An implantable ligation device that achieves male sterilization without cutting the vas deferens.

OBJECTIVES: To determine whether the Vasclip implant procedure would (a) be equivalent to vasectomy in producing azoospermia, (b) produce greater patient satisfaction postoperatively, and (c) result in lower complication rates, postoperative pain, hematoma formation, spermatic granuloma, and surgical site infection when compared with historical controls. METHODS: Sterilization and complications were studied in 124 consecutive patients. RESULTS: Successful sterilization, defined by azoospermia at 10 to 14 months, was observed in 116 of 119 subjects. The effectiveness seemed to be equivalent to that of vasectomy. The incidence of postoperative pain and hematoma formation was similar to that with standard methods. The Vasclip procedure had similar infection rates and seemed to have lower rates of sperm granuloma when compared with vasectomy. In 3 subjects with persistent presence of sperm, histologic examination after traditional vasectomy indicated that misalignment of the device led to partial vas incision with recanalization. Patient acceptability was high: of the clinical study patients, 99% of survey respondents would recommend that other men considering a vasectomy have the Vasclip procedure. CONCLUSIONS: The Vasclip implant procedure represents a new, effective, office-based alternative to vasectomy. Physicians' benefits can include reduced procedural time and reduction of postprocedural complications. Potential patients' benefits include reduced risk of postoperative infection and sperm granuloma formation.