Clifford T. Pereira

Cytokine Expression Profile Over Time In Severely Burned Pediatric Patients

ABSTRACT A severe burn leads to hypermetabolism and catabolism resulting in compromised function and structure of essential organs. The massive release of cytokines is implicated in this hypermetabolic response. The aim of the present study was to compare cytokine expression profiles from severely burned children without signs of infections or inhalation injury (n = 19) to the cytokine profiles from normal, noninfected, nonburned children (n = 14). The Bio-Plex suspension array system was used to measure the concentration of 17 cytokines. The expression of proinflammatory and anti-inflammatory cytokines was maximal during the first week after thermal injury. Significant increases were measured for 15 mediators during the first week after thermal injury: interleukin (IL) 1&bgr;, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 p70, IL-13, IL-17, interferon &ggr;, monocyte chemoattractant protein 1, macrophage inflammatory protein 1&bgr;, and granulocyte colony-stimulating factor (P < 0.05). Granulocyte-macrophage colony-stimulating factor was significantly increased during the second week after burn (P < 0.05). Within 5 weeks, the serum concentrations of most cytokines decreased, approaching normal levels. When compared with the cytokine levels measured in normal children, a total of 16 cytokines were significantly altered (P < 0.05). After severe burn, a specific cytokine expression profile is observed in patients without complications such as inhalation injury or sepsis. The cytokine concentrations decrease during 5 weeks after burn but remain elevated over nonburned values. Furthermore, the elevation in most serum cytokine levels during the first week after burn may indicate a potential window of opportunity for therapeutic intervention.

Longitudinal assessment of Integra in primary burn management: a randomized pediatric clinical trial.

Background:Early excision with autograft-allograft closure is standard in severe burn management. Cadaver skin is associated with risks such as antigenicity, infection, and limited availability and shelf life. Previous studies have shown that Integra is safe to use in burns of <20% total body surface area. However, the suitability of its use in large burns (>50% total body surface area), its effects on postburn hypermetabolism, and the long-term cosmetic and functional results have not yet been evaluated. Materials and Methods:Twenty children with an average burn size of 73 ± 15% total body surface area (71 ± 15% full-thickness burn) were randomized to be treated with either Integra or with autograft-allograft technique. Outcome measures such as length of hospital stay, mortality, incidence of infection and sepsis, acute phase protein levels, and muscle fractional synthetic rate were compared between and within groups during the acute stay (admission to discharge). Outcome measures such as resting energy expenditure, body composition data (measured by dual-energy radiograph absorptiometry), cardiac function indexes, and number of reconstructive procedures were compared during acute hospital stay and at long-term follow-up (up to 2 yrs postinjury). Scar evaluation was performed at long-term follow-up. Results:There were no significant differences between Integra and controls in burn size (70 ± 5% vs. 74 ± 4% total body surface area), mortality (40% vs. 30%), and length of stay (41 ± 4 vs. 39 ± 4 days). In the short term, resting energy expenditure significantly decreased (p < .01), and serum levels of constitutive proteins significantly increased (p < .03) in the Integra group compared with controls. Long-term follow-up revealed a significant increase in bone mineral content and density (24 months postburn, p < .05), as well as improved scarring in terms of height, thickness, vascularity, and pigmentation (12 months and 18–24 months, p < .01) in the Integra group. Conclusion:Integra can be used for immediate wound coverage in children with severe burns without the associated risks of cadaver skin.

Blood transfusions are associated with increased risk for development of sepsis in severely burned pediatric patients

Objective:To determine the risk of developing sepsis following transfusion of blood products in severely burned pediatric patients. Design:Retrospective, cohort study. Setting:Shriners Hospital for Children and University Hospital. Patients:Severely burned pediatric patients with >30% total body surface area (TBSA) burn. Interventions:None. Measurements and Main Results:Two hundred seventy-seven pediatric burn patients over a period of 7 yrs (1997–2004) were included in the study, with 25 patients being septic at admission and therefore excluded. Patients were stratified according to TBSA burn and presence or absence of inhalation injury. The amounts of packed red blood cells (RBCs) and fresh frozen plasma (FFP) were recorded during hospital stay before the development of sepsis. Blood product administration was normalized for the number of surgeries and divided into two groups: high (RBCs >20/FFP >5) or low (RBCs <20/FFP <5) amount of blood products. Sepsis was diagnosed based on the criteria set by the Society of Critical Care Medicine in conjunction with positive blood culture or presence of organisms in the organs at autopsy. By stratifying the groups into low and high blood transfusion, we found that patients with >60% TBSA burn with inhalation injury have an 8% risk of developing sepsis in the low RBC group, which increases to 58% in the high RBC group (p < .05). Similar results were found for RBCs per operation, FFP, and FFP per operation (p < .05). There were no differences in age and gender between groups. Conclusions:Pediatric burn suffering from a 60% TBSA burn with concomitant inhalation injury are more likely to develop sepsis if they are given high amounts of blood products, indicating an immunocompromised state following blood transfusion.

Gene therapy in wound healing: present status and future directions

Gene therapy was traditionally considered a treatment modality for patients with congenital defects of key metabolic functions or late-stage malignancies. The realization that gene therapy applications were much vaster has opened up endless opportunities for therapeutic genetic manipulations, especially in the skin and external wounds. Cutaneous wound healing is a complicated, multistep process with numerous mediators that act in a network of activation and inhibition processes. Gene delivery in this environment poses a particular challenge. Numerous models of gene delivery have been developed, including naked DNA application, viral transfection, high-pressure injection, liposomal delivery, and more. Of the various methods for gene transfer, cationic cholesterol-containing liposomal constructs are emerging as a method with great potential for non-viral gene transfer in the wound. This article aims to review the research on gene therapy in wound healing and possible future directions in this exciting field.

Pathophysiology of the Burn Scar

This chapter reviews current knowledge of the process of wound healing in humans and animals, with special emphasis on abnormal long-term responses to thermal injury. Delays or defects in wound repair lead to aberrant wound healing, and frequently result in pathologic scarring following a severe burn injury. Here we review the wound healing process, including the roles of fibroblasts, keratinocytes, and immune cells in achieving wound closure, the factors that delay wound-healing and result in hypertrophic scarring, and the key pathologic features of hypertrophic scars. Experimental models of hypertrophic scarring—from cell culture to preclinical models to human models—are presented, along with a discussion of areas for further research.

Review paper: Burn coverage technologies: Current concepts and future directions

Skin serves as a protective barrier against the environment. Loss of integrity of the skin through burn injuries can lead to major disability and even death [1]. The accomplishments of the past decade have placed us in the midst of an exciting paradigm shift from what used to be of primary concern (i.e., mortality) to areas that focus on improving the quality of life of burn survivors. Impaired healing and excessive scarring are a major source of morbidity for many burn survivors [2]. The primary goal of treatment of burn wounds are the rapid wound closure and a functional and aesthetically satisfactory scar [2]. Anatomically and functionally the skin has two layers; a superficial layer – the epidermis that provides a barrier against infection and moisture loss; and a deeper dermal layer that is responsible for the elasticity and mechanical integrity of the skin. The epidermal layer is a stratified layer mainly composed of keratinocytes, with proliferating basal cells at the innermost layer and the keratinized, relatively

Sex differences in the long-term outcome after a severe thermal injury.

We have recently shown that during the acute phase, postburn female pediatric burn patients had significantly increased levels of anabolic hormones with an associated decreased hypermetabolism leading to a significant shorter intensive care unit stay compared with male patients. The aim of the present study was to determine possible differences between girls and boys in body composition, hypermetabolism, and hormone pattern in the long term. Sixty-two children (1-16 years old) who sustained a severe thermal injury (≥40% total body surface area) were included into the study. Patients were further divided into girls (n = 22) and boys (n = 40). Patient demographics, nutritional support, and mortality were noted. Resting energy expenditure (REE) was measured by indirect calorimetry, body composition by dual-energy x-ray absorptiometry (Hologic Inc, Waltham, Mass) at discharge, 3, 6, 9, 12, 18, and 24 months after burn. In addition, blood was drawn at the same time points, and serum hormones were measured. There were no significant differences between girls and boys for demographics, nutritional intake, or concomitant injuries. Predicted REE was significantly decreased in girls at discharge, 6, 12, and 18 months postburn (P < 0.05). Dual-energy x-ray absorptiometry scan showed that girls had improved change in bone mineral content and percent fat compared with boys (P < 0.05). There were no differences in changes in height, body weight, lean body mass, and total fat between groups. Girls had significantly higher levels of insulinlike growth factor 1, insulinlike growth factor binding protein 3, free thyroxine index, T4, and insulin when compared with boys (P < 0.05). No differences were found for T3 uptake, osteocalcin, cortisol, growth hormone, and parathyroid hormone (PTH) between groups. Data indicate that girls have a reduced REE associated with changes in bone content and endogenous anabolic hormones.

Optimizing Collagen Scaffolds for Bone Engineering: Effects of Cross-linking and Mineral Content on Structural Contraction and Osteogenesis.

Introduction: Osseous defects of the craniofacial skeleton occur frequently in congenital, posttraumatic, and postoncologic deformities. The field of scaffold-based bone engineering emerged to address the limitations of using autologous bone for reconstruction of such circumstances. In this work, the authors evaluate 2 modifications of three-dimensional collagen-glycosaminoglycan scaffolds in an effort to optimize structural integrity and osteogenic induction. Methods: Human mesenchymal stem cells (hMSCs) were cultured in osteogenic media on nonmineralized collagen-glycosaminoglycan (C-GAG) and nanoparticulate mineralized collagen-glycosaminoglycan (MC-GAG) type I scaffolds, in the absence and presence of cross-linking. At 1, 7, and 14 days, mRNA expression was analyzed using quantitative real-time -reverse-transcriptase polymerase chain reaction for osteocalcin (OCN) and bone sialoprotein (BSP). Structural contraction was measured by the ability of the scaffolds to maintain their original dimensions. Mineralization was detected by microcomputed tomographic (micro-CT) imaging at 8 weeks. Statistical analyses were performed with Student t-test. Results: Nanoparticulate mineralization of collagen-glycosaminoglycan scaffolds increased expression of both OCN and BSP. Cross-linking of both C-GAG and MC-GAG resulted in decreased osteogenic gene expression; however, structural contraction was significantly decreased after cross-linking. Human mesenchymal stem cells-directed mineralization, detected by micro-CT, was increased in nanoparticulate mineralized scaffolds, although the density of mineralization was decreased in the presence of cross-linking. Conclusions: Optimization of scaffold material is an essential component of moving toward clinically translatable engineered bone. Our current study demonstrates that the combination of nanoparticulate mineralization and chemical cross-linking of C-GAG scaffolds generates a highly osteogenic and structurally stable scaffold.

Outcomes of complex gunshot wounds to the hand and wrist: a 10-year level I urban trauma center experience.

Purpose:To assess the consequences of gunshot wounds (GSWs) to the hand, we reviewed our 10-year experience at an urban level I trauma center. Method:A retrospective review was performed on patients admitted with GSWs to the extremities between January 1, 1997 and January 1, 2007. Those with GSWs to the hand and wrist needing surgery were studied. A telephone survey supplemented the data. Results:Of 1358 patients admitted with GSWs involving the upper extremities, 62 patients with complex hand and wrist injuries requiring operative intervention were identified. Most patients sustained low-velocity handgun injuries and presented within 12 hours of injury. In many individuals (97%), the gunshot injury to the hand or wrist was only part of a multiple gunshot assault. All patients underwent surgical debridement and repair followed by an early aggressive rehabilitation program. Mean length of hospital stay was 5.0 (±5.1) days, with 9.7% of patients requiring ICU care for 3.3 (±1.4) days, with an average cost of

Parotid nodular fasciitis in a mobile phone user.

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