Laser-induced vapor nanobubbles improve diffusion in biofilms of antimicrobial agents for wound care.

Being responsible for delayed wound healing, the presence of biofilms in infected wounds leads to chronic, and difficult to treat infections. One of the reasons why antimicrobial treatment often fails to cure biofilm infections is the reduced penetration rate of antibiotics through dense biofilms. Strategies that have the ability to somehow interfere with the integrity of biofilms and allowing a better penetration of drugs are highly sought after. A promising new approach is the use of laser-induced vapor nanobubbles (VNB), of which it was recently demonstrated that it can substantially enhance the penetration of antibiotics into biofilms, resulting in a marked improvement of the killing efficiency. In this study, we examined if treatment of biofilms with laser-induced vapor nanobubbles (VNB) can enhance the potency of antimicrobials which are commonly used to treat wound infections, including povidone-iodine, chlorhexidine, benzalkonium chloride, cetrimonium bromide and mupirocin. Our investigations were performed on Pseudomonas aeruginosa and Staphylococcus aureus biofilms, which are often implicated in chronic wound infections. Pre-treatment of biofilms with laser-induced VNB did enhance the killing efficiency of those antimicrobials which experience a diffusion barrier in the biofilms, while this was not the case for those compounds for which there is no diffusion barrier. The magnitude of the enhanced potency was in most cases similar to the enhancement that was obtained when the biofilms were completely disrupted by vortexing and sonication. These results show that laser-induced VNB are indeed a very efficient way to enhance drug penetration deep into biofilms, and pave the way towards clinical translation of this novel approach for treatment of wound infections.

Evaluating cataract surgery gains by assessing patients' quality of life using the VF-7.

PURPOSE: To describe the development and performance of a questionnaire designed to measure functional impairment caused by cataract. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: The results of a visual-functioning index (VF-14) of 168 patients with first-eye cataract surgery were analyzed. Patients with significant comorbidity were excluded, leaving 142 patients for the final analysis. Snellen visual acuity measurements and complete preoperative and 4 month postoperative clinical status were performed by ophthalmologists. Outcome measures, including the VF-14, patient perception of trouble with vision, patient satisfaction with vision, and the cataract symptom score, were taken by nurses at the preoperative clinical examinations and at the 4 month postoperative visit. The Spearman rank correlation was used to determine which items of the VF-14 best correlated with a change in patient satisfaction. RESULTS: Seven items of the VF-14 that best correlated with patient satisfaction were selected for inclusion in a new 7-item index (the VF-7). Based on the Spearman rank correlation, the items from best to worst were nighttime driving; reading small print; watching television; seeing steps, stairs, or curbs; reading traffic, street, or store signs; cooking; and doing fine handwork. The correlation among changes in the VF-7 score and visual acuity in the operated eye was 0.17, while the correlation among changes in the VF-7 and patient satisfaction caused by cataract surgery was high (r = .56). CONCLUSION: The VF-7 was a strong predictor of change in patient satisfaction caused by cataract surgery.

Confocal laser scanning microscopy of porcine skin: implications for human wound healing studies.

The structure of porcine skin as examined by light microscopy is reviewed and its similarities to and differences from human skin are highlighted. Special imaging techniques and staining procedures are described and their use in gathering morphological information in porcine skin is discussed. Confocal laser scanning microscopy (CLSM) was employed to examine the structure of porcine skin and the findings are presented as an adjunct to the information already available in the literature. It is concluded that CLSM provides valuable additional morphological information to material examined by conventional microscopy and is useful for wound healing studies in the porcine model.

Long-term results of treatment of scalds in children with glycerol-preserved allografts.

A retrospective study followed by a clinical examination was carried out 2-5 years postburn to analyse the long-term results of the treatment of scalds in children (n = 45) with glycerol-preserved allografts. In 21 patients (47 per cent), the wounds healed spontaneously. In 24 patients, remaining defects were closed by a split skin autograft in the third week postburn. Healing without scar formation was seen in 24 patients (53 per cent), 9 patients (21 per cent) showed moderate, and 12 patients (26 per cent) severe scar formation. Transplanted areas showed hyperpigmentation, and donor sites depigmentation. The cosmetic results require further improvement, and classification of present and new methods of treatment. Clinical research is limited by the number of observations and the great variation in wounds. A well-standardized experimental animal model is, therefore, essential.

Histopathological evaluation of scalds and contact burns in the pig model.

A method was developed to inflict standardized scald burns in the New Yorkshire pig. The tissue damage was compared to a standardized contact burn model. On each flank, six localizations were marked in a symmetrical way. Eight scald burns covering 45 cm2 were inflicted by exposing the prepared skin to 500 ml tap water in an applicator at 80 degrees C for 10, 20, 30 and 40 s. Four contact burns were inflicted by applying a brass block of 45 cm2 area, weight 450 gram, with a temperature of 170 degrees C for 10 and 20 s on the skin without exerting pressure. The right flank was used for macroscopic observation, the left flank for histopathological evaluation. Full thickness biopsies were taken at postburn days (PBD) 0, 1, 2, 3 and 21. In the contact burns, a clear demarcation zone of viable and necrotic dermal tissue and vascular damage was observed. The tissue damage in the scalds showed an intermingled pattern of intact and damaged collagen. The more severe scald burns showed a structurally intact superficial vascular plexus, in combination with destruction of the deep vascular plexus. Current and new methods of scald treatment can be classified in this standardized animal model.

A comparative burn wound model in the New Yorkshire pig for the histopathological evaluation of local therapeutic regimens: silver sulfadiazine cream as a standard.

A standard burn wound model was developed in the pig to enable evaluation of histopathological parameters of wound healing under different circumstances. Wounds on one flank were treated with silver sulfadiazine 1% cream (SSD, Flammazine-Duphar), which is a standard treatment. On identical places of the contralateral side different topical agents were applied. From the SSD treated burns a typical histopathologic picture of wound healing under SSD could be derived: SSD has the potential to preserve viable dermal tissue, epidermal regeneration is rather slow and irritated, while the formation of granulation tissue is pronounced, with an abundance of myofibroblasts.