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David N Herndon,
Noe A Rodriguez,
Eva C Diaz,
Sachin Hegde,
Kristofer Jennings,
Ronald P Mlcak,
Jaipreet S Suri,
Jong O Lee,
Felicia N Williams,
Walter Meyer,
Oscar E Suman, Robert E Barrow,
Marc G Jeschke,
Celeste C Finnerty
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ABSTRACT: To determine the safety and efficacy of propranolol given for 1 year on cardiac function, resting energy expenditure, and body composition in a prospective, randomized, single-center, controlled study in pediatric patients with large burns.
Severe burns trigger a hypermetabolic response that persists for up to 2 years postburn. Propranolol given for 1 month postburn blunts this response. Whether propranolol administration for 1 year after injury provides a continued benefit is currently unclear.
One-hundred seventy-nine pediatric patients with more than 30% total body surface area burns were randomized to control (n = 89) or 4 mg/kg/d propranolol (n = 90) for 12 months postburn. Changes in resting energy expenditure, cardiac function, and body composition were measured acutely at 3, 6, 9, and 12 months postburn. Statistical analyses included techniques that adjusted for non-normality, repeated-measures, and regression analyses. P < 0.05 was considered significant.
Long-term propranolol treatment significantly reduced the percentage of the predicted heart rate and percentage of the predicted resting energy expenditure, decreased accumulation of central mass and central fat, prevented bone loss, and improved lean body mass accretion. There were very few adverse effects from the dose of propranolol used.
Propranolol treatment for 12 months after thermal injury, ameliorates the hyperdynamic, hypermetabolic, hypercatabolic, and osteopenic responses in pediatric patients. This study is registered at clinicaltrials.gov: NCT00675714.
Annals of surgery 09/2012; 256(3):402-11. · 7.90 Impact Factor
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ABSTRACT: Recent evidence suggests that female severely burned children have higher endogenous anabolic hormone levels and a shorter ICU stay compared with males. The purpose of this study was to analyze the influence of age and gender on resting energy expenditure (REE) in severely burned children from acute hospitalization through 12 months postburn.
A total of 100 pediatric patients with > 40% total body surface area (TBSA) burn were enrolled in a prospective study and followed by indirect calorimetry measurements. The REE was expressed as actual REE kcal/d, percent of predicted REE, and REE/ body mass index (BMI). Statistical analysis was performed by Student t test and one-way ANOVA for repeated measures. Significance was accepted at P < 0.05.
The measured REE was significantly higher in males versus females at all time points (P < 0.05). The percent of predicted REE was significantly higher in males versus females during the acute hospitalization, at discharge, 6 and 9 months postburn (P < 0.05). The REE/BMI showed a significant difference between males and females at the acute and discharge time period (P < 0.05). In children 3 to 9.9 years of age, the measured REE and the percent of predicted REE were significantly higher in males versus females during the acute study, at discharge and 6 months postburn (P < 0.05). The measured REE at discharge, 9 and 12 months postburn for children >10 years of age was significantly higher in males compared with females (P < 0.05).
Data show that female children exert a decreased hypermetabolic response compared with male children, which may improve burn outcomes in females.
Annals of Surgery 08/2006; 244(1):121-30. · 7.49 Impact Factor
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ABSTRACT: Major trauma and burns are associated with whole body catabolism which can persist for 1 or more years after injury. This study investigates body composition in massively burned children for up to 2 years.
Twenty-five pediatric patients with greater than 40% total body surface area burns were studied. At discharge, 6, 12, 18, and 24 months after burn height, weight, body composition, resting energy expenditure (REE), serum growth hormone, insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), insulin, cortisol, parathyroid hormone, and thyroid hormones were measured. Tukey's test was used for analysis. Significance was accepted at p < 0.05.
Lean body mass, fat mass, bone mineral content, height, and weight increased significantly during the second year after burn. Percent predicted REE decreased significantly, whereas IGFBP-3 and parathyroid hormone levels increased significantly over time. Insulin and T3 uptake were significantly higher at discharge.
Body composition of severely burned children significantly improved in the second year compared with the first year after injury. This demonstrates a need for long-term rehabilitation in these burn patients.
The Journal of trauma 06/2006; 60(5):968-71; discussion 971. · 2.48 Impact Factor
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ABSTRACT: To study the efficacy of growth hormone given to severely burned children from discharge to 12 months after burn and for 12 months after the drug was discontinued.
We have previously shown that low-dose recombinant human growth hormone (rhGH), given to children after a severe thermal injury, successfully improved lean muscle mass, bone mineral content, and growth. The aim of the present study was to investigate long-term functional improvements after treatment.
Forty-four pediatric patients with over 40% total body surface area burns were studied for 24 months after burn. Patients were randomized to receive either rhGH (0.05 mg/kg body weight) or placebo. Height, weight, body composition, serum hormones, resting energy expenditure, cardiac function, muscle strength, and number of reconstructive procedures performed were measured during rhGH treatment and for 12 months after treatment was discontinued. Statistical analysis used Tukey's multiple comparison test. Significance was accepted at P < 0.05.
Height, weight, lean body mass, bone mineral content, cardiac function, and muscle strength significantly improved during rhGH treatment compared with placebo (P < 0.05). This treatment significantly increased GH, IGF-I, and IGFBP-3, whereas serum cortisol decreased (P < 0.05). The number of operative reconstructive procedures was significantly lower with rhGH (P < 0.05). Improvements in height, bone mineral content, and IGF-1 concentrations persisted after rhGH treatment (P < 0.05). No side effects with rhGH were observed.
Administration of rhGH for 1 year after burn was safe and improved recovery. These salutary effects continued after rhGH treatment was discontinued.
Annals of Surgery 06/2006; 243(6):796-801; discussion 801-3. · 7.49 Impact Factor
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Journal of the American College of Surgeons 04/2006; 202(3):536-48. · 4.55 Impact Factor
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ABSTRACT: The objective of this study was to test the hypothesis that hepatomegaly in burned children can be attenuated or reversed by blocking lipolysis and reducing free fatty acids delivered to the liver.
Accelerated lipolysis in severely burned children has been shown to play an important role in the accumulation of hepatic TGs. Severely burned children who survive 10 days or more after injury commonly have enlarged livers often twice or more normal size for their sex, age, and weight.
Ninety-eight children, 2 to 18 years of age, with burns covering more than 40% of their body surface and who received either propranolol (beta-adrenergic blockade) or placebo were studied. Liver weights were measured by ultrasonic scanning. Body composition changes were identified by dual-image x-ray absorptiometry and validated by whole-body potassium-40 scintillation counting. Discarded abdominal cutaneous adipose tissue was collected before and after propranolol or placebo for microarray analysis.
In 80% of severely burned children studied not receiving propranolol, liver sizes increased by 100% or more while 86% of burned children receiving propranolol showed a decrease or no change in liver size over the same period of time after injury. Gene expression patterns of adipose tissue after propranolol treatment showed that all of the identified genes related to lipid metabolism were down-regulated.
Data reported here support the hypothesis that beta-adrenergic blockade can reduce delivery of fatty acids to the liver and hepatic congestion commonly found in severely burned children by inhibiting lipolysis and reducing hepatic blood flow.
Annals of Surgery 02/2006; 243(1):115-20. · 7.49 Impact Factor
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ABSTRACT: Hepatomegaly is a common postmortem observation in severely burned children, with the liver often tripling in size when compared with normal livers for age, weight, and sex. Lesions identified at autopsy include deposition of large and small fat droplets in the hepatocyte, congestion, centrilobular necrosis, and cholestasis. The present study was designed to identify the primary causes of hepatomegaly in severely burned children postmortem. For this purpose, 41 autopsies were reviewed and, when available, blood and tissue samples were studied. Histopathologic findings showed that large intrahepatocytic fat droplets within hepatocytes and cholestasis were important contributors to hepatomegaly. Liver density and wet/dry weight ratios significantly decreased with increasing liver size. Hepatocyte volume increased with increasing liver size (P < 0.001) as did total fat content (P < 0.001). The liver enzymes, alanine aminotransferase and aspartate aminotransferase, remained normal except within 5 to 10 days of injury and 5 to 10 days of death. Triglycerides made up 4% to 70% of the total fat, with the percentage of triglycerides increasing with the severity of hepatomegaly. Saturated fatty acids represented about 85% of the total fatty acids in normal-sized livers, whereas in the largest livers (400% of predicted), only 25% of the fatty acids were saturated. This study provides evidence that 85% to 90% of the hepatomegaly observed in severely burned children postmortem is associated with hepatocyte enlargement, which includes up to 19% intracellular fat. Increases in extracellular protein, intracellular glycogen, and fluid accumulation may make a minor contribution to postburn hepatomegaly.
Shock 12/2005; 24(6):523-8. · 2.85 Impact Factor
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Rene Przkora,
Marc G Jeschke, Robert E Barrow,
Oscar E Suman,
Walter J Meyer,
Celeste C Finnerty,
Arthur P Sanford,
Jong Lee,
David L Chinkes,
Ronald P Mlcak,
David N Herndon
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ABSTRACT: When given to children for 1 year after a severe burn, oxandrolone significantly improves lean body mass, bone mineral content, and muscle strength. The beneficial effects of oxandrolone on height and weight were observed 1 year after treatment was discontinued. To study the efficacy of oxandrolone in severely burned children for 12 months after burn and 12 months after the drug was discontinued.
Oxandrolone attenuates body catabolism during the acute phase after burn. It is unclear whether oxandrolone would have any beneficial effects during long-term treatment or if there were any effects after the drug was stopped.
Sixty-one children with 40% total body surface area burns were enrolled in this study. Patients were randomized into those to receive oxandrolone (n = 30) or placebo (n = 31) for the first 12 months. Treatment was discontinued after 12 months, and the patients were studied without the drug for the following 12 months. At discharge and 6, 12, 18, and 24 months after burn, height, weight, body composition, resting energy expenditure, muscle strength, and serum human growth hormone, insulin-like growth factor-I (IGF-1), IGF binding protein-3, insulin, cortisol, parathyroid hormone, tri-iodothyronine uptake (T3 uptake), and free thyroxine index (FTI) were measured. Statistical analysis used Tukey multiple comparison test. Significance was accepted at P < 0.05.
Oxandrolone improved lean body mass, bone mineral content and muscle strength compared with controls during treatment, P < 0.05. Serum IGF-1, T3 uptake, and FTI were significantly higher during drug treatment compared with controls, P < 0.05. Significant increases in height and weight with oxandrolone were observed after the end of treatment.
Oxandrolone improved body composition and strength in severely burned children during the 12 months of treatment. Its effect on height and weight continued after treatment was discontinued.
Annals of Surgery 10/2005; 242(3):384-9, discussion 390-1. · 7.49 Impact Factor
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ABSTRACT: Cutaneous wounds that involve loss of tissue heal through a complex process of generating granulation tissue to initially cover the wound, followed by epithelialization, and contraction. Normal healing requires a delicate balance between cellular, matrix, and vascularity build up and breakdown. Defects in the regulation of this balance can alter normal scar formation through fibroblastic hyperproliferation, which is characteristic of hypertrophic scar formation.
Primary fibroblasts cultures from hypertrophic scar or adjacent normal skin were seeded in growth medium. Half of each was stimulated with interleukin (IL)-1beta for 6 h and half served as control nonstimulated fibroblasts. Supernatants were tested for expressed proteins and the fibroblasts for changes in gene expression.
Comparison between normal skin and hypertrophic scar fibroblasts stimulated with IL-1beta indicate that 15 genes increased and 8 genes decreased expression. When normal skin was stimulated with IL-1beta, there were increases in the expression of heat shock transcription factor-1, hsp70, and IL-6 When hypertrophic scar was stimulated with IL-1beta, there was a decrease in nuclear factor-kappaB, GADD45-alpha, p53, p53 binding protein, and Cox-2 genes. These genes may play specific but different roles in controlling the cellular response to cell stress and apoptosis.
Data presented suggest that oxidative and heat stress proteins, stimulated through IL-1beta, may be important mediators of abnormal scarring.
Journal of Surgical Research 07/2005; 126(1):59-65. · 2.25 Impact Factor
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ABSTRACT: Several studies have noted gender differences in adult mortality related to thermal injury, however, little is published on gender-related outcomes of burn patients 17 years of age or less. The aim of this study was to evaluate the relationships between mortality, gender, prepubertal and during puberty, ethnic origin, and age, with or without identified sepsis in severely burned children. Seven hundred forty-seven children admitted to our burn hospital from March 1985 to January 2005 with burns greater than 40% total body surface area were studied. Mortality associated with identified sepsis, gender, age, and ethnic origin were outcomes of interest. Two hundred sixty (35%) of the patients studied were girls and 487 (65%) were boys. No significant difference could be shown between girls and boys for the number of operations, time from burn to hospital admission, or the presence of identifiable inhalation injury. Nearly 60% of the male nonsurvivors and 48% of the female nonsurvivors in this study had identifiable sepsis at postmortem. The mortality rate was higher in infants and toddlers, age 0 to 2.9 years, compared with children and adolescents, age 3 to 17 years; however, there was no significant difference in rate of mortality between genders, prepuberty versus puberty, those with septic episodes, or ethnic origin. Burn mortality among infants and toddlers, children, and adolescents with greater than 40% total body surface area burns with or without identified sepsis could not be shown to be gender or ethnic origin dependent.
Shock 07/2005; 23(6):485-7. · 2.85 Impact Factor
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ABSTRACT: Protein degradation, negative nitrogen balance and compromised structure of essential organs have been associated with resistance and decreased production of anabolic hormones. In turn, increased levels of anabolic hormones are associated with improved survival. The aims of the present study were to determine the pattern of anabolic hormones, resting energy expenditure and cytokines in severely thermally injured pediatric patients and to compare these parameters in female and male patients.
Sixty-five children (1 to 16 years of age) sustaining a severe thermal injury (> or =40% TBSA) were included into the study. Patients were further divided into females (n = 22) and males (n = 43). Patient demographics, nutritional support, incidence of sepsis, inhalation injury, and mortality were noted. Resting energy expenditure was measured during hospital course by indirect calorimetry. Blood was drawn 0, 10, 20, and 40 days postburn and serum insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-1 and -3 (IGFBP-1, and -3), growth hormone, insulin, and cytokines were measured.
There were no significant differences between females and males for demographics, nutritional intake, or concomitant injuries. In both groups, endogenous anabolic agents were drastically decreased by 3- to 5-fold up to 40 days posttrauma. Females had significantly higher levels of IGF-I, IGFBP-3, growth hormone, and insulin when compared with males, P < 0.05. Increased levels of anabolic hormones were associated with decreased stay on the ICU (females 36 +/- 22 days versus males 53+/- 39 days), decreased serum IL-1beta and TNF-alpha as well as resting energy expenditure, P < 0.05.
Data indicate that despite adequate nutritional support, severe thermal injury leads to decreased anabolic hormones over a prolonged period of time. Female patients had significantly increased levels of anabolic hormones, which are associated with decreased proinflammatory mediators and hypermetabolism, leading to a significant shorter ICU stay compared with male patients.
Annals of Surgery 05/2005; 241(5):759-67; discussion 767-8. · 7.49 Impact Factor
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ABSTRACT: The purpose of this study was to identify gene-expression changes in leg muscle for up to 24 months after a severe thermal injury.
Hypermetabolism associated with severe burns was thought to cease with wound healing and closure. It has been recently shown that hypermetabolism does not completely resolve after healing, and muscle catabolism continues after hospital discharge; however, just how long after discharge has not been established.
: Six children, admitted to our hospital within 1 week after injury, were studied. Patients ranged in age from 3 to 18 years, with flame or scald burns covering more than 40% of their body surface area. At 1.5, 6, 12, 18, and 24 months postburn, a biopsy of the vastus lateralis muscle was taken and snap frozen at -80 degrees C. Total RNA was isolated and in vitro transcribed and hybridized to HG-U95 Av.2 Affymetrix arrays. The images were scanned and analyzed using Affymetrix GeneChip Analysis Suite 5.2 and dChip programs. Using 1 to 7 days after injury as baseline, comparisons were made of expression profiles at the various time intervals after injury.
When comparisons are made to nonburned children, 38 genes were significantly altered at 1.5 months, 10 genes remained altered at 6 months, 4 remained altered at 12 months, and 2 at 18 months. No differences could be shown at 24 months. Western blot analysis of beta-2 microglobulin and myosin light chain was used to corroborate the microarray data.
Gene changes can be identified for up to 18 months after burn but not at 24 months. These gene changes may provide information concerning what genes in skeletal muscle contribute to recovery from burn trauma.
Annals of Surgery 05/2005; 241(4):647-53. · 7.49 Impact Factor
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ABSTRACT: Thermal injury is associated with a pronounced catabolic response in skeletal muscle. This study identifies gene expression changes in skeletal muscle of thermally injured girls and boys using high-density oligonucleotide arrays.
Six burned children with a mean age of 8.3 +/- 1.3 years and TBSA burn size covering 51 +/- 6% admitted to our hospital with in 48 h of injury and six cleft lip and cleft palate patients were studied. Total RNA was isolated, in vitro transcribed, and hybridized to HG-U95 Av.2 Affymetrix arrays. Messenger RNA expression patterns of controls and burn patients were compared using Affymetrix GeneChip Analysis Suite 5.2 and dChip.
Statistical analysis of the 12,625 genes on each array showed a significant increase in the expression of 77 genes in burn children and a decrease in 21 genes when compared to controls (P < 0.05). We found three genes in burned males and two genes in burned females with decreased expression in muscle compared to controls. Chromosomes 1, 2, 7, 12, and 16 showed genes with increased expression in muscle from burned children, while chromosomes 3, 7, 8, 19, and 22 had genes with decreased expression. Categories of genes affected were related to metabolism, proliferation, transcription/translation, immune response, stress response, angiogenesis, and signal transduction.
Genes that are differentially expressed in skeletal muscle of burned children, but whose function in muscle is unknown, include those related to various transcription factors and those known to encode proteins involved in signaling pathways. Further analysis is required to achieve the ultimate goal of making functionally relevant conclusions about the molecular pathology of burn injury.
Journal of Surgical Research 02/2005; 123(1):144-52. · 2.25 Impact Factor
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Critical Care Medicine 11/2004; 32(12):A2. · 6.33 Impact Factor
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ABSTRACT: The acute phase response is a cascade of events contributing to hypermetabolism and substrate catabolism. It was believed to persist for only a short time after injury. There is now evidence that systemic catabolism and hypermetabolism associated with thermal injury persevere for a long time. We hypothesize that the proinflammatory hepatic acute phase response perseveres for an extended time and enhances hypermetabolism longer than previously believed.
Prospective study.
Intensive Care Burn Unit, Shriners Hospital for Children.
Twenty-three children (aged 1-16 years) sustaining a severe thermal injury (>/=40% total-body surface area) who remained in the intensive care unit longer than 30 days.
Patient demographics, nutritional support, incidence of sepsis, inhalation injury, mortality, and levels of serum constitutive proteins, type I and type II acute phase proteins, free fatty acids, proinflammatory cytokines, insulin-like growth factor (IGF) I, IGF binding protein-1, IGF binding protein-3, and hepatocyte growth factor.
After thermal injury, constitutive hepatic protein levels decreased 2- to 3-fold 80 days after burn, whereas acute phase protein levels increased. Free fatty acid levels were increased 5 days after burn. Proinflammatory cytokine levels (interleukin [IL] 1, IL-6, IL-8, IL-10, and tumor necrosis factor) and IGF binding protein-1 levels were elevated for 40 days after burn, whereas serum IGF-I and IGF binding protein-3 levels were decreased. Hepatocyte growth factor levels were increased immediately after burn but rapidly returned to the normal range.
Despite adequate nutritional support, a severe thermal injury induces the proinflammatory acute phase response for a prolonged period. Thus, the liver with the hepatic acute phase response plays a more important role during catabolism after burn than previously believed. Pharmacologic agents that improve hepatic function may be an effective approach to attenuate hypermetabolism after trauma.
Archives of Surgery 07/2004; 139(6):641-7. · 4.24 Impact Factor
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ABSTRACT: The structural rearrangement of collagen fibres in hypertrophic scar causes abnormal contracture, low tensile strength, and raised scars, which cause functional impairment and disfigurement. It is hypothesized that changes in the genes of cytokines, extracellular matrix proteins, and proteins regulating programmed cell death are related to hypertrophic scar formation. To test this hypothesis, fibroblasts were cultured from hypertrophic scars and their response to interleukin-6 (IL-6) stimulation was studied by defining their gene expression profiles. Affymetrix gene chip analysis was used to identify up- or down-regulation in the 12 625 genes present in the affymetrix array. RT-PCR and ELISA assays were used to validate microarray expression profiles further. Comparison of gene profiles showed an increase of 12 genes in hypertrophic scar fibroblasts compared with normal skin fibroblasts, while the expression of 14 genes decreased. Thirty-three genes were affected by IL-6 treatment in the hypertrophic scar fibroblasts, while 57 genes were affected in normal skin fibroblasts. Messenger RNA to beta-actin ratios for matrix metalloproteinase-1 (MMP-1) and MMP-3 were increased with IL-6 in normal skin fibroblasts from 2.43 +/- 0.06 to 5.50 +/- 0.45 and from 0.75 +/- 0.09 to 1.98 +/- 0.01, respectively. No change in these matrix metalloproteinases could be shown with IL-6 stimulation in hypertrophic scar fibroblasts. Secreted protein levels of pro-MMP-1 and MMP-3 were elevated in the supernatants from normal skin fibroblasts from 2.00 +/- 0.09 and 1.72 +/- 0.10 ng/ml to 4.60 +/- 0.12 and 3.41 +/- 0.20 ng/ml, respectively, after treatment with IL-6 (p < 0.05). No changes were observed in hypertrophic scar fibroblasts treated with IL-6. Values are means +/- SEM. The absence of any up-regulation of MMP-1 and MMP-3 in hypertrophic scar fibroblasts, in response to IL-6, suggests that suppression of matrix metalloproteinases may play a role in the excessive accumulation of collagen formed in hypertrophic scars. While the pathogenesis of abnormal hypertrophic scars remains poorly understood, the use of gene expression arrays may prove helpful in identifying the mechanisms responsible for this type of abnormal scar formation and in formulating an effective therapeutic protocol.
The Journal of Pathology 04/2004; 202(4):476-85. · 6.32 Impact Factor
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ABSTRACT: The liver plays an important role in a severe thermal injury by modulating immune function, inflammatory processes and the acute phase response, which are an orchestrated attempt to restore homeostasis. Using high-density oligonucleotide arrays, we examined the gene expression profile in the livers of rats between 2 and 240 h after a 40% total body surface area (TBSA) burn. Alterations in gene expression unique to a thermal injury were identified. Approximately 39 genes out of 8700 genes on each array across all the time points showed a significant change in expression patterns. Real time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses verified significant changes in early growth response-1 (Egr-1) messenger RNA (mRNA) and protein levels corresponding to the array data. Significant increases in serum levels of alpha-2-macroglobulin that correspond to changes in its mRNA levels were observed at 6 and 24 h after burn, p<0.05. The genomic pattern for liver in the hypermetabolic phase after the burn injury involves transcription factors, stress and inflammatory responses, cytoskeletal and extracellular matrix modifications, and regulation of cell proliferation and differentiation. During the initial phase of thermal injury gene expression profiles in the liver may provide some insight into how cellular protection mechanisms and systemic hypermetabolism are initiated and controlled. The genome wide changes observed may provide a rational therapeutic strategy to improve burn care.
Gene 03/2004; 327(1):51-60. · 2.34 Impact Factor
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ABSTRACT: Pulmonary failure has emerged as one of the leading causes of mortality in burned children due, in part, to the success in reducing the incidence of sepsis, early surgery and fluid resuscitation, and new advances in nutritional support. To evaluate the effect of pulmonary injury, age, gender, race, and burn size on mortality, the records of 3179 burned children admitted to our burn center from 1985 to 2001 were reviewed. In this population, 1246 were admitted within 14 days of injury with burns greater than 20% of their total body surface area (TBSA).
Lethal burn areas (LAs) for a thermal injury only or burn plus inhalation injury were estimated from best fit probit curve within 95% confidence limits. Data analysis was by chi(2)-test, t-test, or Fisher's exact test where appropriate.
The lethal burn area for a 10% mortality rate with and without concomitant inhalation injury was a 50 and 73% TBSA burn, respectively. Children up to the age of 3 with >/=20% TBSA burns had a higher rate of mortality (9.9%) compared to those 3-12 years of age (4.9%) and 13-18 years of age (4.2%). Children with 21-80% TBSA burns showed a significant difference in mortality (P<0.05) between those with burn plus inhalation injury (13.9%) and burn only (2.9%), while those with 81-100% TBSA burns showed no significant difference between burn only and burn plus inhalation injury.
Inhalation injury remains one of the primary contributors to burn mortality. Children under the age of 3 years, however, are at a higher risk both with and without inhalation injury.
Burns 02/2004; 30(1):72-7. · 1.96 Impact Factor
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ABSTRACT: Propranolol, a nonselective beta-blocker, has been shown effective in hypermetabolic burn patients by decreasing cardiac work, protein catabolism, and lipolysis. This study investigates the effect of propranolol on gene and protein expression changes in skeletal muscle of burned children by use of high-density oligonucleotide arrays to establish the genetic profiles and stable isotope technique to quantitate protein synthesis. Thirty-seven children (mean age 9.7 +/- 1.1 yr) were randomized into groups to receive placebo (n = 23) or propranolol (n = 14) titrated to reduce heart rate by 15%. Children had >40% total body surface area burns (mean 43 +/- 5.6%). Protein net balance was determined by stable-isotope infusion technique. Total RNA from muscle biopsies was isolated, labeled, and cRNA hybridized to the HG-U95Av2 Affymetrix array. Mean net balance of protein synthesis and breakdown was -14.3 +/- 12.9 nmol. min-1. 100 ml leg volume-1 for placebo and +69.3 +/- 34.9 nmol. min-1. 100 ml leg volume-1 in the propranolol-treated children (P = 0.012). Comparison of 12,000 genes in burned children receiving placebo showed increased expression of two genes with time, whereas children receiving propranolol showed increased expression of nine genes with a decrease in five genes. We conclude that burned children receiving propranolol showed a significant upregulation in genes involved in muscle metabolism and downregulation of an important enzyme involved in gluconeogenesis and insulin resistance compared with burned children receiving placebo. The upregulation of genes involved in muscle metabolism correlates well with the increase in net protein balance across the leg.
AJP Endocrinology and Metabolism 10/2003; 285(4):E783-9. · 4.75 Impact Factor
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ABSTRACT: In this study, we investigated the effect of inflammatory cytokines on matrix metalloproteinase (MMP-1) and TIMP-1 production in human dermal fibroblasts, which play a pivotal role in wound healing, ranging from the synthesis and remodeling of extracellular matrix (ECM) to the synthesis of growth factors. The balance of MMPs and TIMPs is crucial in directing successful wound repair. Human adult dermal fibroblasts were seeded in six well plates (7.5 x 10(4) cells/ml) in complete media. Eighty to ninety percent confluent cells were treated with interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) (10 ng/ml) for 6h in serum free media with suitable controls run in triplicate. Supernatants were assayed for pro-MMP-1 & TIMP-1. Extracted total RNA was used for reverse transcription polymerase chain reaction (RT-PCR) with sequence specific primers for MMP-1, TIMP-1 and beta-actin. Signal intensity was normalized to the internal control (beta-actin). Statistical analysis used ANOVA. MMP-1 and TIMP-1 mRNA expression were markedly increased with IL-6 and TNF-alpha treatment and remains unchanged with IL-1beta. Pro-MMP-1 protein levels are unchanged with TNF-alpha and significantly increased with IL-1beta and IL-6 treatment. However, TNF-alpha significantly increases TIMP-1 protein levels. Data suggests differential regulation of MMP-1 and TIMP-1 protein levels by the cytokines found in stimulated dermal fibroblasts. Further characterization of this response will provide an understanding of the mechanisms of pathogenesis of extracellular matrix (ECM) and the potential role of metalloproteinases in tissue remodeling after injury.
Burns 09/2003; 29(6):527-31. · 1.96 Impact Factor
