Thermal and electrical injuries

Through progress in wound management, resuscitation, intensive care treatment, and a coordinated rehabilitation process, modern burn care has been able to deliver substantial increases in survival and improvement in functional outcomes for burn victims. The development of regionalized burn centers has contributed greatly to this progress. As the field of burns matures, burn centers are preparing to meet future challenges through collaborative efforts in disaster management and outcomes research.

Self-reports of anxiety in burn-injured hospitalized adults during routine wound care

The purpose of this investigation was to examine the amount of anxiety patients believed tolerable and the amount of anxiety experienced during routine burn wound care. Participants included 47 hospitalized adults who provided data for four consecutive assessment periods. Patients (mean TBSA, 16%; range, 2-70%) were primarily Caucasian (87%) and had an average hospital stays of 23 days (range, 11-130). Reports of what level of anxiety they would be able to tolerate and what level of anxiety had been experienced were assessed using 10-point Graphic Rating Scales. The use of anxiolytic was recorded, and patient suggestions for reducing anxiety were obtained. The single most commonly endorsed anxiety treatment goal was 0, although 53% consistently chose a treatment goal other than 0 (range, 1-6). Two repeated-measure analyses of variance indicated that the amount of anxiety patients could tolerate and the amount they reported experiencing did not change over the course of time. Paired t-tests revealed that patients routinely reported more anxiety than they considered tolerable. Analyses of anxiety reports of patients treated with anxiolytics (n = 6) vs patients receiving no anxiolytics (n = 41) revealed inconsistent differences in actual anxiety and treatment goals across time. In general, patient suggestions for lessening anxiety included requests for education, communication, additional medications, and manipulation of the hospital environment. Anxiety for burn-injured, hospitalized adults remains a concern. Our findings are consistent with the literature indicating that adult patients hospitalized for burn wound care report appreciable anxiety, over and above what they consider "tolerable." Continued research is needed and should include investigations into the relationship between pain and anxiety during routine wound care.

An Analysis of the Long-Distance Transport of Burn Patients to a Regional Burn Center

The concentration of specialized burn care to relatively few centers within relatively large geographic regions requires an organized system of patient triage, referral, and transport. The purpose of this study was to identify systematic errors in either the initial evaluation or care of burn patients requiring transport more than 90 miles to a single regional burn center. Therefore, we undertook a descriptive analysis of patients transported more than 90 miles to a single regional burn center from 2000 to 2003. The outcomes of interest were duration of transport, errors in burn size estimation, errors in fluid management, appropriateness of intubation, and complications during transport. During the years 2000 to 2003, there were 1877 admissions to the burn center; 949 (51%) were transferred from an outside facility. Of these 949, 424 (45%) were transferred more than 90 miles from a referring facility to our burn center. The average transport time from injury to our burn center was 7.2 hours (range, 1.6-48). There were no patient deaths during transport, and the most common complications were loss of or inability to secure intravenous access and inability to secure an airway. Burn size estimates differed significantly (P < .001) between referring providers and burn center physicians. This study confirms that patients can be transported safely and efficiently over long distances to a regional burn center. Given the current geographic distribution of burn centers and concerns about declining numbers of burn surgeons, organized systems of patient triage and transport may become increasingly important.

Arterial and Venous Complications of Heparin-Induced Thrombocytopenia in Burn Patients

Heparin-induced thrombocytopenia (HIT) is an antibody-mediated complication of heparin treatment that can result in a number of devastating thrombotic complications. Given the common use of heparin for deep venous thrombosis prophylaxis in patients with burns, we reviewed the incidence and complications of HIT in our burn center. We performed a retrospective review of all patients treated with heparin at our burn center who underwent testing for HIT from 2001 to 2005. Screening for HIT was performed by platelet factor 4 enzyme-linked immunoassay. Records were reviewed with particular attention to indications for HIT testing, duration of heparin therapy, type of heparin used (fractionated vs unfractionated), indication for heparin use (prophylactic vs therapeutic), treatment of HIT, and complications of HIT. During the 4-year study period, 625 patients received heparin therapy at some point during their hospital course. Of these patients, 43 (6.9%) underwent testing for HIT and 10 of the 43 screened patients (23%) were positive; the incidence among all heparinized burn patients was 1.6%. Thrombotic complications of HIT included arterial thrombosis requiring limb amputation (two patients), deep venous thrombosis (three patients), and pulmonary embolism (two patients). One patient died, presumably secondary to a pulmonary embolism. All patients were anticoagulated after HIT diagnosis, and four patients developed bleeding complications. HIT is a potentially devastating complication of heparin administration. Whereas our overall incidence of HIT was low, HIT+ patients developed significant complications, including arterial and venous thrombosis, pulmonary embolus, limb loss, and death. Treatment for such HIT-related thromboses usually resulted in bleeding complications requiring transfusions. The routine use of heparin for deep venous thrombosis prophylaxis needs to be carefully considered in light of these potential complications.

Inflammation and the host response to injury: an overview of the multicenter study of the genomic and proteomic response to burn injury

Inflammation and the Host Response to Injury is a prospective, multicenter, federally funded collaborative study of the genomic and proteomic basis for injury response. This study has brought together clinical specialists in burn injury with experts in genomics, proteomics, and bioinformatics to answer questions related to immunoinflammatory responses to injury. The purpose of this report is to describe the structure, organization, goals, and current progress of this Glue Grant project.

Correlation of Clinical Outcome of Integra Application with Microbiologic and Pathological Biopsies

BACKGROUND

Integra, a dermal replacement template consisting of bovine collagen, chondroitin-6-sulfate, and a silastic sheet is a postexcisional treatment for deep partial to full thickness burns where autograft is limited. This study correlates Integra histology and quantitative microbiology cultures with clinical outcomes after autografting.

METHODS

Charts of 29 burn patients who underwent Integra treatment and neodermis biopsy at the time of ultra thin autografting were reviewed. We analyzed microbial contamination, inflammatory reaction, and autograft take.

RESULTS

The mean burn size and age were 43% total body surface area and 39 years old, respectively. In quantitative neodermis cultures, 90% of samples had bacterial growth; nine samples (31%) had > 10(5) colony forming units per gram. The most common organism was Staphylococcus aureus (31%). Patients with quantitative bacterial counts >10(5) CFU/g received targeted systemic antibiotics. Integra take (83%) and autograft take (92%) were acceptable even in patients with high bacterial counts (78% Integra take; 86% autograft take). More than 50% of biopsies had dermal regeneration similar to normal dermis; foreign body reactions were unusual. Histologic evidence of inflammation, especially polymorphonuclear cells, was increased in biopsies with high bacterial counts.

CONCLUSION

Integra and autograft take can be acceptable even with high bacterial counts if wounds are treated with appropriate targeted topical and systemic antibiotics in the presence of microbial contamination. Neodermis biopsies showed fibrous in-growth congruent with existing Integra fibers with minimal foreign body reaction. These data support Integra use as a safe and effective treatment modality in patients with major burns.

An outcome analysis of patients transferred to a regional burn center: transfer status does not impact survival

BACKGROUND

Optimal burn care is provided at specialized burn centers. Given the geographic location of these centers, many burn patients receive initial treatment at local emergency departments prior to transfer. The purpose of this study was to determine whether patients transferred from other facilities have worse outcomes than those admitted directly from the field.

STUDY DESIGN

A retrospective cohort study was performed comparing the outcomes of patients admitted to our burn center directly from the field with patients requiring transfer from a preliminary care facility. The outcomes of interest were mortality, length of stay, length of stay/TBSA burned, number of operations and hospital charges. Poisson regression or Cox proportional hazards model was used to evaluate differences in outcomes after adjusting for potential confounders.

RESULTS

From 2000 to 2003 a total of 1877 patients were admitted to our burn center and 953 (51%) were transferred from a preliminary care facility. No difference (p<0.05) was found in length of stay, number of operations, hospital charges and mortality between the two cohorts.

CONCLUSIONS

This study demonstrates that patients transferred to a regional burn center from local hospitals have equivalent mortality, length of stay and hospital charges as those admitted directly from the field.

Histology of the thick scar on the female, red Duroc pig: final similarities to human hypertrophic scar

The etiology and treatment of hypertrophic scar remain puzzles even after decades of research. A significant reason is the lack of an accepted animal model of the process. The female, red Duroc pig model was described long ago. Since the skin of the pig is similar to that of humans, we are attempting to validate this model and found it to be encouraging. In this project we quantified myofibroblasts, mast cells and collagen nodules in the thick scar of the Duroc pig and compared these to the values for human hypertrophic scar. We found the results to be quite similar and so further validated the model. In addition, we observed that soon after wounding an inflammatory cell layer forms. The thickness of the inflammatory layer approaches the thickness of the skin removed as if the remaining dermis "knows" how much dermis is gone. In deep wounds this inflammatory layer thickens and this thickness is predictive of the thickness of the ultimate scar.

Complex Wound Management Utilizing an Artificial Dermal Matrix

The benefits of the Integra Dermal Regeneration Template in the management of extensive burn injuries have been well documented. Integra can reduce donor- and graft-site scarring and has been reported to be capable of vascularizing over small areas of exposed bone and tendon. Given these potential advantages, we have used Integra for a variety of other reconstruction applications. We performed a retrospective review of patients with complex wounds treated with Integra at our burn center. Integra was used in the management of a variety of wounds, including necrotizing fasciitis, extremity degloving injury, meningococcemia, Marjolin ulcer, postburn lip reconstruction, and fourth-degree burns with exposed bone or tendon. Engraftment rates of Integra and autograft were 98% +/- 4% and 97% +/- 4%, respectively. All areas of graft loss healed without need for regrafting. The benefits of Integra in the management of acute burn wounds can be extended to other traumatic and complex wounds.

Effect of blood transfusion on outcome after major burn injury: a multicenter study

OBJECTIVE

To delineate blood transfusion practices and outcomes in patients with major burn injury.

CONTEXT

Patients with major burn injury frequently require multiple blood transfusions; however, the effect of blood transfusion after major burn injury has had limited study.

DESIGN

Multicenter retrospective cohort analysis.

SETTING

Regional burn centers throughout the United States and Canada.

PATIENT POPULATION

Patients admitted to a participating burn center from January 1 through December 31, 2002, with acute burn injuries of >or=20% total body surface area.

OUTCOMES MEASURED

Outcome measurements included mortality, number of infections, length of stay, units of blood transfused in and out of the operating room, number of operations, and anticoagulant use.

RESULTS

A total of 21 burn centers contributed data on 666 patients; 79% of patients survived and received a mean of 14 units of packed red blood cells during their hospitalization. Mortality was related to patient age, total body surface area burn, inhalation injury, number of units of blood transfused outside the operating room, and total number of transfusions. The number of infections per patient increased with each unit of blood transfused (odds ratio, 1.13; p<.001). Patients on anticoagulation during hospitalization received more blood than patients not on anticoagulation (16.3+/-1.5 vs. 12.3+/-1.5, p<.001).

CONCLUSIONS

The number of transfusions received was associated with mortality and infectious episodes in patients with major burns even after factoring for indices of burn severity. The utilization of blood products in the treatment of major burn injury should be reserved for patients with a demonstrated physiologic need.

SCORTEN Overestimates Mortality in the Setting of a Standardized Treatment Protocol

Toxic epidermal necrolysis (TEN) is a rare, severe, exfoliative disorder with a high mortality rate. SCORTEN is a recently developed scoring system that estimates severity and predicts mortality in patients with TEN based on seven independent clinical risk factors recorded within the first 24 hours of admission. An increasing SCORTEN level predicts a higher mortality rate. For more than 20 years, the treatment of TEN at our institution has involved the use of a standardized clinical pathway that includes removal of sloughed epidermis, dermal protection with porcine xenograft, early enteral nutrition, and critical care monitoring. We hypothesize that this standardized clinical approach will result in a lower mortality rate than predicted by SCORTEN. A retrospective review was performed on all patients treated for TEN using the standardized pathway from February 1987 to March 2004. SCORTEN was calculated in each patient. One hundred nine patients were treated for TEN during the study period. Overall observed mortality was 20% compared with a SCORTEN predicted mortality of 30%, resulting in a relative reduction in mortality of 33% (P = .011). In addition, observed probability of death was lower than predicted at all levels, except at SCORTEN score of 6 or greater. In conclusion, TEN remains a life-threatening disease with a high mortality rate. Our standardized treatment protocol results in significantly improved outcomes compared to those predicted by SCORTEN.

Incidence and Characteristics of Hospitalized Patients with Pressure Ulcers: State of Washington, 1987 to 2000

BACKGROUND

Pressure ulcers complicate the hospital course of critically injured or ill patients. Guidelines have been promulgated to prevent pressure ulcers in hospitalized patients. The purpose of this study was to determine whether these guidelines have, in fact, reduced the incidence of pressure sores.

METHODS

The authors examined census data from the National Center for Health Statistics and the Washington State Department of Health for the 14-year period 1987 through 2000 and identified patients with a pressure ulcer listed as the primary diagnosis (International Classification of Diseases, Ninth Revision, Clinical Modification code 707.0) and patients admitted for other diagnoses with pressure ulcer as a secondary diagnosis. The authors reasoned that patients who were admitted for treatment of pressure ulcers would have the diagnosis listed as primary, whereas those who were admitted for other reasons and developed pressure ulcers during the admission would have pressure ulcer listed as a secondary diagnosis. Other available data included patient age, sex, procedures for pressure ulcers (International Classification of Diseases, Ninth Revision, Clinical Modification codes 15920 through 15999), length of stay, and hospital charges for care.

RESULTS

The incidence of pressure ulcers as a primary diagnosis varied from 7.0 to 8.3 per 100,000 population but did not change over the 14-year study period. The rate of operation for these ulcers also did not change. The incidence of pressure ulcers as either a primary or secondary diagnosis doubled from 34.5 to 71.6 per 100,000 (p < 0.001), whereas the incidence of operative procedures for these ulcers did not change.

CONCLUSION

The authors found no evidence that the guidelines for the prevention of pressure ulcers have been effective in decreasing pressure ulcer formation, but it may be that pressure ulcers are now being reported in a more thorough manner.

The optimal time for early excision in major burn injury

INTRODUCTION

Early excision and grafting (E&G) drastically changed burn care in America by reducing morbidity, mortality and hospital length of stay (LOS). The present study was intended to determine whether an optimal time window exists between resuscitation and wound sepsis for the first E&G in a patient with a large burn.

MATERIAL AND METHOD

The authors conducted a retrospective study of patients admitted between January 1994 and December 2000 with > or = 40% TBSA burns and at least 1 E&G procedure. Patients were grouped according to the day of their first operation. Patients allowed to heal indeterminate burns prior to excision and grafting of deep partial or full thickness burns were grouped as > or = d7 and were excluded from the present study. The authors correlated the time of first excision with infection, mortality and LOS.

RESULTS

Seventy-five patients were identified and 12 patients allowed to heal indeterminate burn prior to excision and grafting of deep partial or full thickness burns were excluded. Sixty-three remaining patients included 51 males and 12 females. Mean burn size was 49% of total body surface area (TBSA) (44% deep partial or full thickness) and the mean age was 36 years. There were 61 flame (2 combined with electrical injuries), 1 scald and 1 chemical burn. Twelve died (19%) and 52 patients developed 121 infections. Whereas there was no statistical difference in mortality for patients operated on different days (p > 0.2), 60% of patients operated within the first 48 hours after injury died; this was not significant due to a small patient number

CONCLUSIONS

The present data suggest that patients who undergo early excision and grafting within seven days following a major burn > or = 40% TBSA have equivalent infection or mortality rates regardless of when the first operation occurs between post burn day(PBD) 2 and PBD 7 (p > 0.2).

Elevated Orbital Pressure: Another Untoward Effect of Massive Resuscitation after Burn Injury

BACKGROUND

Fluid resuscitation remains a fundamental component of early burn care management. However, recent studies suggest that excessive volumes of resuscitation are being administered. Overresuscitation results in negative sequelae including abdominal and extremity compartment syndromes. Elevated intraocular pressure (IOP) has been described as another potentially devastating effect of massive fluid resuscitation in trauma patients. The orbit, similar to the abdomen and extremity, is a compartment, limited to expansion from edema anteriorly by the eyelids and orbital septum, and posteriorly by the bony orbital walls. The purpose of this study was to review the incidence of elevated IOP in a series of patients with major burn injury.

METHODS

We retrospectively reviewed the charts of 13 consecutive patients admitted to our burn center with burn sizes >25% total body surface area (TBSA). All patients underwent serial IOP measurements for the first 72 hours following admission. Medical records were reviewed for fluid resuscitation volume, IOP measurements, need for canthotomy, and results of canthotomy procedures.

RESULTS

Five of 13 patients had IOP >30 mm Hg and required lateral canthotomy. Canthotomy immediately reduced IOP (p = 0.009). Patients who developed elevated IOP received a significantly larger fluid resuscitation (9.0 cc/kg/%TBSA versus 6.0 cc/kg/%TBSA, p = 0.02). Elevated IOP was significantly associated with delivery of larger fluid resuscitation volume (p = 0.027).

CONCLUSIONS

Massive fluid resuscitation following burn injury can result in orbital compartment syndrome requiring lateral canthotomy. Early diagnosis and treatment of orbital compartment syndrome should be incorporated into the management of patients with major burn injury receiving large fluid resuscitation volume.

Social support correlates with survival in patients with massive burn injury

Large burn size, inhalation injury, age, and associated trauma increase the rate of mortality after burns. However, not all patients with large burns and significant risk factors die. In this study, we wanted to determine other presenting factors that might indicate a survival benefit for burn patients with large burns. We reviewed charts of 36 patients with burns > or =60% TBSA that were aggressively resuscitated at the University of Washington Burn Center from 1990 to 2000 to determine whether survivors of large burns exhibit presenting variables that predict survival. Patients who had comfort care measures initiated at admission were excluded from this analysis. Survivors (n = 16) and nonsurvivors (n = 20) had no significant differences in age, total burn size, inhalation injury, or need for escharotomy. Full-thickness burn size was significantly smaller for survivors (58%) than for nonsurvivors (73%; P = .02). Survivors (81%) were more likely than nonsurvivors to have social support (35%; P = .007). A full-thickness burn > or =80 % TBSA was the only variable uniformly associated with mortality, suggesting that patients who survive large burns have a partial-thickness component that heals without surgery. The difference in degree of social support was one unique distinction that may impact patient survival and is worth further investigation.

The Versajet??? Water Dissector: A New Tool for Tangential Excision

Goulian and Watson knives work well for tangential burn excision on large flat areas. They do not work well in small areas and in areas with a three-dimensional structure. The Versajet Hydrosurgery System (Smith and Nephew, Key Largo, FL) is a new waterjet-powered surgical tool designed for wound excision. The small size of the cutting nozzle and the ability to easily maneuver the water dissector into small spaces makes it a potentially useful tool for excision of burns of the eyelids, digits and web spaces. The Versajet Hydrosurgery System contains a power console that propels saline through a handheld cutting device. This stream of pressurized saline functions as a knife. We have used the Versajet for burn excision in 44 patients. Although there is a learning curve for both surgeons using and operating room staff setting up the device, the Versajet provides a relatively facile method for excision of challenging aesthetic and functional areas.

Patterns of grease burn injury: Development of a classification system

Grease burns occur commonly in the home during food preparation. It has been our observation that grease burns follow a particular pattern of injury. The purpose of this study was to review our institutional experience in the management of these burns to develop a classification scheme. We performed a retrospective review of patients admitted to our burn center with grease burns. Subjects were identified through our database and their charts were reviewed with particular attention to burn distribution, TBSA and need for grafting. We excluded workplace burns and children under the age of six. A total of 249 patients who fit the above criteria were admitted with grease burns to our burn center from 1993 to 2003. The sequence of events leading to burn and its distribution followed a consistent pattern. The majority of patients (86%) had an isolated upper extremity burn or upper extremity burn in combination with a face, trunk or lower extremity burn. Forty percent of patients required at least one excision and grafting procedure. Grease burns associated with cooking at home follow predictable patterns of injury. Based on these patterns we proposed a classification system for domestic grease burns.

Adult Campfire Burns: Two Avenues for Prevention

Campfires are a common component of outdoor festivities. Pediatric campfire burns have been well described. Adult campfire injuries also are common and have several important distinguishing characteristics. We performed a retrospective review of adult patients admitted with campfire burns to our burn center from July 1998 to July 2003. Medical records were reviewed with attention to mechanism of injury, intoxication level, burn size, and surgeries performed. A total of 27 patients with this injury were treated as inpatients over the course of the study period. Two distinct mechanisms of injury emerged: 1) contact with the campfire and 2) flash/flame injuries from igniting the fire. Eighty-one percent (13/16) of patients who sustained contact burns were intoxicated, as compared with 11% (1/11) of those who sustained flash/flame injuries. Nearly half of the patients with contact burns and more than half the patients with flash/flame burns required excision and grafting.

Management of facial burns with a collagen/glycosaminoglycan skin substitute-prospective experience with 12 consecutive patients with large, deep facial burns

Management of deep facial burns remains one of the greatest challenges in burn care. We have developed a protocol over the past 20 years for management of facial burns that includes excision and coverage with thick autograft. However, the results were not perfect. Deformities of the eyelids, nose and mouth as well as the prominence of skin graft junctures demonstrated the need to explore novel approaches. Integra has been used with success in the management of burns of the trunk and extremities. The purpose of this study was to prospectively evaluate the aesthetic outcome of the use of Integra for deep facial burns. Twelve consecutive patients underwent excision of large, deep facial burns and placement of Integra. Integra provides excellent color and minimally visible skin graft junctures. The texture is good but not as supple as thick autograft. Integra is not well suited for use in the coverage of eyelid burns due to the need to wait 2 weeks for adequate vascularization. In summary, thick autograft remains the gold standard for deep facial burns. However, for patients with extensive burns and limited donor sites, Integra provides an acceptable alternative.

Substance P Levels and Neutral Endopeptidase Activity in Acute Burn Wounds and Hypertrophic Scar

BACKGROUND

Substance P, a cutaneous neuroinflammatory mediator released from peripheral nerves, plays a role in responses to injury. Neutral endopeptidase is a cell membrane-bound metallopeptidase enzyme that regulates substance P activity. The question of substance P involvement in hypertrophic scar development has been based on observations that hypertrophic scars have increased numbers of nerves. The authors hypothesized that hypertrophic scar has greater substance P levels and decreased neutral endopeptidase activity compared with uninjured skin and acute partial-thickness burns, which may contribute to an exuberant response to injury.

METHODS

The authors obtained small skin samples of deep partial-thickness burns (n = 7; postburn days 7 to 78) and uninjured skin (n = 14) from patients (eight male patients and six female patients; 2 to 71 years old) undergoing burn wound excision. Hypertrophic scar samples were obtained from six patients (three male patients and three female patients; 8 to 47 years old) undergoing surgical excision 13 to 64 months after burn injury. Protein concentrations were determined using a bicinchoninic acid assay. Substance P concentration was determined by means of indirect enzyme-linked immunosorbent assay. Neutral endopeptidase activity was measured using an enzymatic assay that quantifies a fluorescent degradation product, methoxy-2-naphthylamine (MNA). Substance P and neutral endopeptidase data were standardized to sample weight.

RESULTS

Substance P levels were greater in hypertrophic scar (3506 pg/g) compared with uninjured skin (1698 pg/g; p < 0.03) and burned skin (958 pg/g; p < 0.01). Hypertrophic scar samples had decreased neutral endopeptidase enzyme activity (8.8 pM MNA/hour/microg) compared with normal skin (16.3 pM MNA/hour/microg; p < 0.05). Acute burn wounds (27.9 pM MNA/hour/microg) demonstrated increased neutral endopeptidase enzyme activity (p < 0.05).

CONCLUSIONS

Increased substance P concentration in hypertrophic scar correlates with histologic findings of increased nerve numbers in hypertrophic scar samples. Decreased neutral endopeptidase enzyme activity in hypertrophic scar may contribute to increased available substance P that may result in an exuberant neuroinflammatory response.

Antioxidants inhibit fatty acid and glucose-mediated induction of neutral endopeptidase gene expression in human microvascular endothelial cells

BACKGROUND

Neutral endopeptidase (NEP) is a membrane-bound metallopeptidase that degrades tachykinins and may regulate their role in wound repair. NEP enzyme activity is increased in diabetic wounds and skin compared with normal controls. We have shown that unsaturated fatty acids and glucose upregulate NEP activity in human microvascular endothelial cells (HMECs) and that vitamins E and C reduce this effect.

STUDY DESIGN

To determine whether these changes involve NEP gene expression regulation, we analyzed NEP mRNA levels in HMECs cultured with elevated glucose (40 mM) and fatty acids oleate (40 microM) and linoleate (40 microM) for 48 hours or 1 month. Cells were exposed for an additional 48 hours to antioxidants vitamins E or C or N-acetylcysteine. Total RNA was extracted and analyzed for NEP mRNA using real-time reverse transcriptase polymerase chain reaction. NEP gene expression was standardized to beta-actin mRNA and results were analyzed using ANOVA.

RESULTS

Elevated glucose, oleate, and linoleate upregulated NEP mRNA in short and longterm HMEC cultures, but did not alter rate of NEP mRNA degradation. Vitamins E and C and N-acetylcysteine blocked glucose- and fatty acid-induced NEP mRNA (p < or = 0.05). The potential role of oxidative stress in NEP activation was confirmed by demonstrating that elevated glucose and fatty acids increase H(2)O(2) levels in HMECs.

CONCLUSIONS

Regulation of NEP enzyme activity by glucose and fatty acids appears to include gene expression transcription as well as modulation of enzyme activity. Our results also suggest that oxidative stress may be involved in upregulation of NEP by fatty acids and glucose.

Changes in VEGF and nitric oxide after deep dermal injury in the female, red Duroc pig—further similarities between female, Duroc scar and human hypertrophic scar

Despite decades of research, our understanding of human hypertrophic scar is limited. A reliable animal model could significantly increase our understanding. We previously confirmed similarities between scarring in the female, red, Duroc pig and human hypertrophic scarring. The purpose of this study was to: (1) measure vascular endothelial growth factor (VEGF) and nitric oxide (NO) levels in wounds on the female Duroc; and (2) to compare the NO levels to those reported for human hypertrophic scar. Shallow and deep wounds were created on four female Durocs. VEGF levels were measured using ELISA and NO levels with the Griess reagent. VEGF and NO levels were increased in deep wounds at 10 days when compared to shallow wounds (p < 0.05). At 15 weeks, VEGF and NO levels had returned to the level of shallow wounds. At 21 weeks, VEGF and NO levels had declined below baseline levels in deep wounds and the NO levels were significantly lower (p < 0.01). We found that VEGF and NO exhibit two distinctly different temporal patterns in shallow and deep wounds on the female Durocs. Furthermore, NO is decreased in female, Duroc scar as it is in human, hypertrophic scar further validating the usefulness of the model.