Andrew Burd

A comparative study of the cytotoxicity of silver‐based dressings in monolayer cell, tissue explant, and animal models

Over the past decade, a variety of advanced silver‐based dressings have been developed. There are considerable variations in the structure, composition, and silver content of these new preparations. In the present study, we examined five commercially available silver‐based dressings (Acticoat™, Aquacel® Ag, Contreet® Foam, PolyMem® Silver, Urgotul®SSD). We assessed their cytotoxicity in a monolayer cell culture, a tissue explant culture model, and a mouse excisional wound model. The results showed that Acticoat™, Aquacel® Ag, and Contreet® Foam, when pretreated with specific solutes, were likely to produce the most significant cytotoxic effects on both cultured keratinocytes and fibroblasts, while PolyMem® Silver and Urgotul®SSD demonstrated the least cytotoxicity. The cytotoxicity correlated with the silver released from the dressings as measured by silver concentration in the culture medium. In the tissue explant culture model, in which the epidermal cell proliferation was evaluated, all silver dressings resulted in a significant delay of reepithelialization. In the mouse excisional wound model, Acticoat™ and Contreet® Foam indicated a strong inhibition of wound reepithelialization on the postwounding‐day 7. These findings may, in part, explain the clinical observations of delayed wound healing or inhibition of wound epithelialization after the use of certain topical silver dressings. Caution should be exercised in using silver‐based dressings in clean superficial wounds such as donor sites and superficial burns and also when cultured cells are being applied to wounds.

Plasma cell-free DNA as an indicator of severity of injury in burn patients.

Abstract Background: Raised levels of plasma cell-free DNA have been detected in various patient groups, including trauma patients. We hypothesized that plasma DNA is increased in burn patients and may represent an objective indicator of burn severity and have predictive as well as prognostic significance. Methods: This was a prospective clinical study with full ethical approval. With informed consent, blood samples were collected from 28 burn patients within 24h of injury and from 12 control subjects. Plasma cell-free DNA was measured by real-time quantitative polymerase chain reaction (PCR) assay for the β-globin gene. Descriptive analysis, non-parametric data comparison tests (Mann-Whitney) and correlation tests (Spearman rank) were performed on the data. Results: Samples were taken at a mean time of 5.7h after injury from 13 patients with flame/flash burns and 15 patients with scalds. Median plasma DNA levels in the control, scald and flame/flash burn patient groups were 287, 648 and 2685 kilogenome-equivalents/L, respectively. Plasma DNA levels correlated with the length of hospital stay, but not with admission to the intensive care unit (ICU) nor the length of ICU stay. DNA levels correlated with the burn surface area (Spearman rank r=0.54, p=0.04) and the number of operations needed (Spearman rank r=0.55, p=0.03) for scalds, but not for flame/flash burns. Conclusions: Plasma DNA is increased after burn injury and is significantly correlated with some outcome measures, including the length of hospital stay. DNA levels are higher in flame/flash patients than in scald patients; the difference may provide an objective indication of burn depth and inhalation injury.

Perineum reconstruction with pedicled anterolateral thigh fasciocutaneous flap

Eighteen pedicled anterolateral thigh perforator island flaps were used for complex perineal reconstructions between May 2003 and May 2005. The patients’ average age was 48.6 years (range, 32 to 64 years), and the average follow-up period was 8 months (range, 2 to 13). In 7 cases, the perforator was septocutaneous and in 11 it was intramuscular. The application of the pedicled anterolateral thigh fasciocutaneous flap is described perineum reconstruction. The size of the perineum defects ranged from 6 × 9 cm to 16 × 17 cm, and the size of the transferred flap ranged from 8 × 11 cm to 18 × 20 cm. All flaps survived. One patient developed minor wound dehiscence in the posterior aspect of the perineal wound because of fecal contamination and skin maceration. The esthetic appearance of the reconstructed perineum was good. Despite a variable vascular anatomy that can give rise to some surgical challenge in raising the flap, the authors conclude that this is a safe and reliable flap for perineal reconstruction.

A new technique of vaginal reconstruction with the deep inferior epigastric perforator flap: a preliminary report.

Background: Vaginal reconstruction after tumor resection or in congenital vaginal agenesis remains a challenging area in surgery, with many techniques previously described underlining the continued search for an ideal method. In this preliminary report, a series of patients are presented who underwent vaginal reconstruction using a deep inferior epigastric artery perforator (DIEP) flap. Methods: Between May of 2004 and February of 2005, five patients underwent vaginal reconstruction using the pedicled DIEP flap. Four patients had congenital vaginal agenesis and one had a complete vaginal resection because of a tumor. Results: The flaps ranged in size from 9 × 10 cm to 11 × 12 cm. All flaps survived, although one patient developed a posterior space hematoma that required draining. Of the five patients, two were sexually active and enjoyed satisfactory penetrative intercourse after reconstruction. Conclusions: This series demonstrates that a new vagina can be created from the pedicled DIEP flap and that the reconstruction is reliable, with low donor-site morbidity. The major disadvantage of this technique is the conspicuous abdominal scar.

HA modulation of epidermal morphogenesis in an organotypic keratinocyte-fibroblast co-culture model.

Please cite this paper as: HA modulation of epidermal morphogenesis in an organotypic keratinocyte‐fibroblast co‐culture model. Experimental Dermatology 2010; 19: e336–e339.

Low-dose 5-fluorouracil induces cell cycle G2 arrest and apoptosis in keloid fibroblasts

Background  Intralesional injection of low‐dose 5‐fluorouracil (5‐FU) has recently been used as an experimental modality for treating keloid scarring and has shown promising efficacy in improving scar appearance and preventing recurrence of the keloid.

Allogenic skin: transplant or dressing?

The use of biological dressings is an established aspect of contemporary burns care. The type and source of these biological materials can give rise to both legal and ethical issues. This paper looks at these issues in relation to allogenic skin. It is argued, from a medical perspective, that non-viable allogenic skin, cannot be transplanted and so should therefore be classified both medically and legally as a dressing.

A study of Q‐switched Nd:YAG laser irradiation and paracrine function in human skin cells

Background and objectives: This preliminary laboratory‐based study looks at the paracrine release from human skin cells subject to sublethal Q‐switched Nd:YAG 532 nm laser irradiation.

CD9 Is Critical for Cutaneous Wound Healing through JNK Signaling

Cutaneous injury triggers a cascade of signaling events essential for wound re-epithelialization. CD9, a cell-surface protein, has been implicated in a number of cellular processes by coupling to intracellular signaling; however, its exact role in wound healing remains unidentified. We reported that CD9 was downregulated in migrating epidermis, and reelevated to basal level when re-epithelialization was completed. Although low level of CD9 appears to be required for normal wound healing, a significant healing delay was found in CD9-null mice, with wounds gaping wider on day 5 and day 7 post wounding. Further analysis showed that re-epithelialization was adversely affected in CD9-null mice, due to impaired migration of epidermis. Notably, CD9 deficiency caused a persistent enhancement of C-JUN NH2 terminal kinase (JNK) signaling primarily in migrating epidermis with abnormal elevation of matrix metalloproteinase (MMP)-9 detected in CD9-null wounds, leading to excessive degradation of type IV collagen, and thus a defective basement membrane at the wound site. JNK suppression reduced MMP-9 production and therefore ameliorated the healing delay with the appearance of significantly elongated migrating epidermis in CD9-null mice. Our study demonstrated the importance of CD9 in wound re-epithelialization, linking this molecule directly to basement membrane formation and epidermal migration through participating in the regulation of the JNK/MMP-9 pathway.

An update review of stem cell applications in burns and wound care

The ultimate goal of the treatment of cutaneous burns and wounds is to restore the damaged skin both structurally and functionally to its original state. Recent research advances have shown the great potential of stem cells in improving the rate and quality of wound healing and regenerating the skin and its appendages. Stem cell-based therapeutic strategies offer new prospects in the medical technology for burns and wounds care. This review seeks to give an updated overview of the applications of stem cell therapy in burns and wound management since our previous review of the “stem cell strategies in burns care”.