Systemic antimicrobial prophylaxis in burn patients: systematic review.

OBJECTIVE: To review studies of systemic antibiotic prophylaxis in burn patients. METHODS: Electronic databases were searched for human clinical trials performed between 1966 and 2016 that compared prophylactic systemic antibiotics with placebo or no intervention. RESULTS: Nineteen trials met the selection criteria. Early postburn prophylaxis was assessed in non-severe burn patients (six trials) and severe burn patients (seven trials). Antimicrobial prophylaxis showed no effectiveness for the prevention of toxic shock syndrome or burn wound infection (Grade 1C), but could be useful in patients with severe burns and requirement for mechanical ventilation (Grade 2B). Perioperative prophylaxis was assessed in six trials. Antimicrobial prophylaxis during resection of devitalized tissue is of no benefit in most burn patients (Grade 2B); however, there is insufficient evidence to make a recommendation for patients with extensive burns. Antibiotic prophylaxis may also be effective in preventing split-thickness skin graft infections in selected procedures (Grade 2B). CONCLUSIONS: The available evidence does not support the role of systemic antibiotic prophylaxis in the management of the majority of burn patients. Nevertheless, it may be useful in patients with severe burns who require mechanical ventilation, and in selected split-thickness skin grafting procedures.

A survey of methods for the evaluation of tissue engineering scaffold permeability.

The performance of porous scaffolds for tissue engineering (TE) applications is evaluated, in general, in terms of porosity, pore size and distribution, and pore tortuosity. These descriptors are often confounding when they are applied to characterize transport phenomena within porous scaffolds. On the contrary, permeability is a more effective parameter in (1) estimating mass and species transport through the scaffold and (2) describing its topological features, thus allowing a better evaluation of the overall scaffold performance. However, the evaluation of TE scaffold permeability suffers of a lack of uniformity and standards in measurement and testing procedures which makes the comparison of results obtained in different laboratories unfeasible. In this review paper we summarize the most important features influencing TE scaffold permeability, linking them to the theoretical background. An overview of methods applied for TE scaffold permeability evaluation is given, presenting experimental test benches and computational methods applied (1) to integrate experimental measurements and (2) to support the TE scaffold design process. Both experimental and computational limitations in the permeability evaluation process are also discussed.

HIV-1 Tat mimetic of VEGF correlates with increased microvessels density in AIDS-related diffuse large B-cell and Burkitt lymphomas.

Angiogenic switch marks the beginning of tumor's strategy to acquire independent blood supply. In some subtypes of non-Hodgkin's lymphomas, higher local vascular endothelial growth factor (VEGF) expression correlates with increased microvessel density. However, this local VEGF expression is higher only in tumors with elevated expression of the receptors of the growth factor, suggesting an autocrine growth-promoting feedback loop. Several studies have indicated that VEGF receptors are also targeted by Tat protein from the HIV-1-infected cells. Given the similarity of the basic region of Tat to the angiogenic factors (basic fibroblast growth factor, VEGF), Tat mimics these proteins and binds to their receptors. We evaluated the role of HIV-1 Tat in regulating the level of VEGF expression and microvessel density in the AIDS-related diffuse large B-cell (DLBCL) and Burkitt lymphomas (BL). By luciferase assay, we showed that VEGF promoter activity was downregulated in vitro in cells transfected with Tat. Reduced VEGF protein expression in primary HIV-1 positive BL and DLBCL, compared to the negative cases, supported the findings of promoter downregulation from the cell lines. Microvascular density assessed by CD34 expression was, however, higher in HIV-1 positive than in HIV-1 negative tumors. These results suggest that Tat has a wider angiogenic role, besides the regulation of VEGF expression. Thus, targeting Tat protein itself and stabilizing transient silencing of VEGF expression or use of monoclonal antibodies against their receptors in the AIDS-associated tumors will open a window for future explorable pathways in the management of angiogenic phenotypes in the AIDS-associated non-Hodgkin's lymphomas.