Reduced Hepatic Expression of Glutathione S-Transferases in Burned Mice

BACKGROUND

Glutathione S-transferases (GSTs) contribute to liver homeostasis and are released into plasma after liver injury. This study investigates the hepatic expression of key GST enzyme subtypes after burn injury.

METHODS

Mice were subjected to an 18% total body surface area burn. Expression of mGSTalpha3 and mGSTmu1 was analyzed by reverse-transcriptase polymerase chain reaction and Western blots on liver preparations from burned and control mice. GST catalytic activity was measured by conjugation assays.

RESULTS

: In burned animals, mGSTalpha3 mRNA was only reduced at 1 day, whereas mGSTmu1 mRNA decreased at 1 day and at 3 days after injury. Total mGSTmu protein levels decreased at the same time points, whereas total mGSTalpha protein levels did not change. Also, by 3 days, total GST conjugation activity was reduced by 25% (p=0.05).

CONCLUSION

Reduced expression of specific alpha and mu GST enzymes after burns correlates functionally with reduced GST activity. Altered GST expression may contribute to liver damage after systemic injury.

Saturday-morning television: do sponsors promote high-risk behavior for burn injury?

Television has become an important tool for learning and socialization in children. Although television violence has been associated with adverse effects, data on depiction of fire and burn injury are lacking. We sought to determine whether Saturday-morning television programming, viewed primarily by children, depicts fire and burn injury as safe or without consequence, thus potentially increasing the incidence of burn injury in children. This was a prospective observational study. Saturday-morning children's television programs were videotaped from 7 AM to 11 AM for eight different television networks during a 6-month period. Tapes were scored for scenes depicting fire or smoke by independent observers. Recorded items included show category, scene type, gender target, context of fire, and outcome after exposure to flame. Fire events were documented during programs and their associated commercials. A total of 108 hours of children's programs, 16 hours per network, were recorded. Scenes depicting fire or smoke were identified 1960 times, with 39% of events occurring during the program itself and 61% in commercials. Fire was depicted as either safe or without consequence in 64% of incidents. Action adventure stories accounted for 56% of flame depictions. Overall, one incident involving flame and fire was portrayed for each 3 minutes of television programming. Saturday-morning television programming frequently depicts fire as safe, empowering, or exciting. The incidence of flame use in programming varies between stations but is most prevalent in action/adventure stories. Television commercials, although brief, provide the majority of the misinformation regarding fire. Medical professional societies should alert the public to this potential hazard and recommend responsible portrayal of fire in children's television programming.

Burn injury induces an inhibitory signal in the lung Smad pathway

Smad signaling mediates the cellular response to transforming growth factor-beta (TGF-beta). We hypothesize that variations in Smad signaling modify the response to TGF-beta signaling in the lung after injury. C57BLKS/J mice were subjected to an 18% surface area burn injury, sacrificed at specific time points and their lung tissue was harvested. Lung TGF-beta1 expression, as determined by RT-PCR, ELISA and PAI/Luciferase assay, was not affected by injury. Western blots for Smad2/3 and Smad4 on nuclear fractions revealed decreased Smad2, Smad3, and Smad4 protein levels at 3h, while their total cellular levels did not differ from control mice. Smad7 protein increased transiently at 3 h. Correlating with Smad inhibition, transcription in type I alpha-2 collagen was also transiently depressed. By RT-PCR, Smad3 and Smad7 mRNAs decreased at 3 h, while Smad2 and Smad4 mRNA levels remained constitutive. Burn injury did not alter lung TGF-beta1 expression but caused Smad inhibition through decreased nuclear translocation of Smad2, Smad3, and Smad4, and upregulated Smad7. Transcription was not the key regulatory step in Smad protein expression, as transient decreases in Smad3 and Smad7 mRNA did not correlate with protein levels. It appears that Smad activity may in part attenuate TGF-beta activity after burn injury.

Sequential induction of Hsp25 and proliferating cell nuclear antigen in the kidney after burn

Burn injury elicits a wide range of intracellular signaling events leading to alterations in phenotypes of distant organs. Renal dysfunction is one of several serious postburn complications. To better understand the underlying mechanisms of renal dysfunction among burn patients, we investigated alterations in the expression of heat shock proteins (Hsps) and cell cycle-associated proteins in the kidney after burn. Following an approximately 18% total body surface area burn, blood and kidney samples were harvested from mice at several time points. Serum levels of blood urea nitrogen increased significantly at 3 h and returned to basal levels at Day 1 implying a transient dysfunction of glomerular filtration. The expression of Hsp25 was increased at Day 1, whereas no changes in Hsp70 expression were observed. An increase in proliferating cell nuclear antigen (PCNA), a marker of cell proliferation, peaked at Day 3, and its expression was predominantly limited to cells appearing to be tubular epithelial cells in the cortex. In contrast, no significant alterations in the p21 mitosis inhibitor were noted. Furthermore, increases in histones H1 and H2A at Day 3 paralleled the PCNA induction suggesting a burn-mediated alteration in cell cycle activities. The results from this study suggest that a sizeable burn may trigger sequential activation of signaling events involved in the early pathogenesis and subsequent recovery of the kidney after burn.

CD14-mediated alterations in transcription and splicing of endogenous retroviruses after injury

Increase in systemic levels of lipopolysaccharide (LPS) contributes to the pathogenesis of distant organ injury after burn. Stress signals elicited from burn influence transcriptional activities of mouse endogenous retroviruses (MuERVs) in various distant organs. The involvement of LPS pathways in the burn-mediated regulation of MuERVs in the spleen was investigated in this study. Spleen harbors substantial numbers of tissue macrophages, a key responder to LPS stimulation. Spleen tissues collected from CD14 (LPS receptor) knockout (KO) and wild type (WT) mice after burn were subjected to RT-PCR analysis of MuERV expression. There was a substantial induction of 2 bands and a marked downregulation of a band in CD14 KO mice compared to WT mice after burn. Sequence analysis of these CD14- and burn-dependent bands identified 3 new alternatively spliced and 2 defective env transcripts of MuERVs as well as novel splicing signals. Chromosomal loci of putative MuERVs sharing the unique U3 sequences of these transcripts were mapped by surveying the entire genome of C57BL/6J mice. In addition, coding potentials, transcriptional regulatory elements, and adjacent cellular genes of these putative MuERVs were analyzed. The results from these studies suggest that injury-triggered LPS/CD14 signaling events play roles in the transcriptional regulation of certain MuERVs carrying unique U3 promoter sequences.

Blood transfusion in burns: what do we do?

Over 11 million units of blood are transfused yearly in the United States. Although blood transfusion is common in burns, data are lacking on appropriate transfusion thresholds. The purpose of the study was to identify current burn center physician blood transfusion practices. A 30-question survey of blood transfusion practices was developed and sent to burn center directors. The survey assessed demographics, burn experience, and blood transfusion thresholds. Physicians were asked to list factors affecting their blood transfusion thresholds and then to give their blood transfusion threshold for patients based on age and percent burn. The final section presents three case scenarios with alterations in one physiological parameter to assess the effect on transfusion thresholds. A total of 55 of the 180 surveys (31%) were returned. Mean number of burn beds was 15.7 +/- 1.4, with 264 +/- 25 burn admissions per year. The respondents had been in burn care for 15.9 +/- 1.4 years. Their mean hemoglobin transfusion threshold was 8.12 +/- 1.7 g/dl. The most frequent reasons for transfusion were ongoing blood loss (22%), anemia (20%), hypoxia (13%), and cardiac disease (12%). Inhalation injury influenced the decision to transfuse blood in 34%. The hemoglobin level below which respondents would transfuse blood increased with increasing TBSA burn, history of cardiac disease, acute respiratory distress syndrome, and age. Blood transfusion thresholds in burns vary based on burn percentage, age, and presence of cardiac disease. To date, no standard of care exists for blood transfusions in burns. Future prospective studies are needed to determine the appropriate use of blood in burns.

Injury-associated differential regulation of histone expression and modification in the thymus of mice

One of the key events in the regulation of gene expression is chromatin remodeling involving histone regulation. We investigated the effects of burns on the expression of histone that might be associated with altered molecular and pathological profiles in the thymus. A markedly decreased expression of histone variant H2A.1 mRNA was identified in the thymus after burn during a differential display experiment. Subsequently, we examined the histone expression (mRNA and protein) and posttranslational modification in the thymus after burn. Also, changes in proliferating cell nuclear antigen (PCNA), a central molecule in chromatin assembly, was examined. Reverse-transcription polymerase chain reaction analysis revealed a transient decrease in the expression of several histone variants (H2A.1, H1(r1), H3-B, H3-1, and H4-D) mRNAs in the thymus at 1 day after burn. A decrease in histone subtypes H2A, H2B, H3, and H4, but not H1, was demonstrated 1 and 3 days after burn according to the results of Western blot. Furthermore, there were different levels of decreases in acetylated and dimethylated forms of histone H3 1 and 3 days after burn. In addition, decreased levels of PCNA were evident in the thymus 1 day after burn. Changes in the expression of histones and PCNA may reflect mere decrease in proliferating cells and/or a reorganization of the chromatin structure associated with altered transcriptional activities, eventually contributing to the phenotypic changes in the thymus after burn.

Split thickness skin grafting for recreation of the scrotum following Fournier's gangrene

Fournier's gangrene is an infection of the genitals and perineum that is treated with extensive soft tissue debridement, often leading to loss of scrotal skin. Multiple options for reconstruction of the scrotum are available. Four cases of recreation of the scrotum with meshed split thickness skin grafts (STSG) are presented. The discussion includes a comparison of STSG with other treatment options. We conclude that STSG are a safe, technically easy treatment option with satisfactory cosmetic and functional results.

Treadmills: A Preventable Source of Pediatric Friction Burn Injuries

Treadmills are a burn risk for children. A child's hand can get trapped in the conveyor belt, causing friction burns to the underlying tissue. The purpose of this retrospective study was to review the characteristics and treatment of treadmill-related burns in children from 1998 to 2002. Ten patients, at a mean age of 3.4 years, sustained injuries associated with treadmill use. Trapping of the hand between the conveyor belt and the base was the most frequent injury mechanism. Burn location was predominantly on fingers and palms. Four patients required operative intervention. All patients required specialized wound care as well as scar management and occupational therapy. Treadmills pose a danger to children. Current safety devices are ineffective for preventing serious hand injuries in children. New design modifications and public awareness are needed to improve child safety.

Involvement of CD14 and Toll-Like Receptor 4 in the Acute Phase Response of Serum Amyloid A Proteins and Serum Amyloid P Component in the Liver After Burn Injury

Acute phase proteins such as serum amyloid A proteins (SAAs) and serum amyloid P component (SAP) are induced in the liver after various insults (e.g., infection, injury). The cellular and molecular mechanisms controlling the expression of these acute phase proteins may be specifically designed for different insults. The roles of two central molecules of the lipopolysaccharide (LPS)-mediated inflammation pathway (CD14 and toll-like receptor 4 [Tlr4]) were investigated for the regulation of SAAs and SAP in the liver of mice after an 18% total body surface area burn injury. RT-PCR analysis revealed a subtype- and time-dependent induction of SAA mRNAs between 3 h and 3 days, while there was a peak induction of SAP mRNA at day 1. Marked elevations of SAA and SAP protein levels at day 1 supported the mRNA data. Furthermore, a differential regulation of SAAs and SAP mRNAs was noted between CD14 knockout (KO) and their control mice after injury. SAA protein was induced to a lesser degree after injury in C3H/HeJ (Tlr4-defective) mice than in their control mice. In addition, in both CD14 KO and C3H/HeJ mice, the induction of SAP protein was significantly reduced compared with respective controls. These data provide evidence that CD14 and Tlr4 participate, at least in part, in a cascade of signaling events that control the immediate-early and differential induction of SAAs and SAP in the liver after injury. They also suggest that LPS may be one of the initial inducing agents associated with these acute phase responses in the liver after injury.

Expression of transforming growth factor beta1 in patients with and without previous abdominal surgery

HYPOTHESIS

Transforming growth factor beta1 (TGF-beta1) plays an important role in the formation of adhesions after abdominal operations.

DESIGN

Prospective, observational study.

SETTING

University-based, tertiary referral center.

PATIENTS

Patients undergoing elective open abdominal operations were recruited and divided into 2 groups. Twenty-two patients with a history of abdominal surgery were designated as study patients, and 10 patients with no history of abdominal surgery served as controls.

INTERVENTIONS

Samples of normal peritoneum, peritoneal scar tissues, and serum were obtained from all patients at the time of surgery.

MAIN OUTCOME MEASURES

Samples were assayed for total TGF-beta1 expression using an enzyme-linked immunosorbent assay.

RESULTS

Scar tissues expressed significantly greater amounts of TGF-beta1 (0.47 pg/ micro L) compared with normal peritoneal tissue from both study patients (0.29 pg/ micro L; P =.03) and controls (0.17 pg/ micro L; P =.002). Serum TGF-beta1 levels were also higher in study patients (1.71 pg/ micro L) compared with controls (1.22 pg/ micro L; P =.02). Neither adhesion nor serum TGF-beta1 expression correlated with time since last operation, total number of previous operations, or severity of intra-abdominal adhesions.

CONCLUSION

These results suggest that TGF-beta1 may play an important role in human peritoneal adhesion formation.

The Circle of Safety: A Campfire Burn Prevention Campaign Expanding Nationwide

Camping is a popular family activity, especially during the spring and summer months. Campfires are a common activity among campers. They offer a source of recreation but also pose a risk for severe burns. The rising number of children with campfire burns seen at our institution triggered a quest for a campaign for the prevention of these injuries. A chart review was performed to study the characteristics and the circumstances of burn injuries of all children treated for campfire-related injuries over a 4-year period between 1997 and 2001. Thirty-two children sustained campfire-related burn injuries, with 88% being under the age of 7. The children had either fallen into the campfire or walked into simmering coals. All accidents would have been prevented if the children had kept a safe distance from the campfire. Normal growth charts were used to determine the average height of 7-year-old children as being 48 inches. A campaign was started to encourage families to keep a safe distance of 4 feet from their campfires by drawing a "circle of safety" with a stick on the ground 4 feet away from the fire.

Alterations in the expression and modification of histonesin the liver after injury

Chromatin remodeling plays a key role in the transcriptional activation of regulatory factors in the liver in response to a variety of stress signals. The effects of burn injury on histone expression and its modification were investigated in this study. Liver tissues collected after a flame burn injury were subjected to RT-PCR and Western blot analyses of histone regulation. There was a marked induction of histone H3-D variant mRNA at 3 and 6 h. In contrast, histone H2A.2 variant mRNA had a downregulation at 3 days. No apparent changes were noted in other histone variants examined. Western blot analysis revealed a downregulation of all 5 histone subtypes (H1, H2A, H2B, H3, and H4) at 1 day and there was a subsequent induction of H1 and H2A subtypes at 3 days after injury. There was an induction of modified forms (phospho-, acetyl-, and dimethyl-) of histone H3 subtype at day 3. Furthermore, a transient elevation in PCNA (proliferating cell nuclear antigen) levels was apparent in the liver at day 3, which parallels the induction of phospho-histone H3, which is a mitosis marker. These findings suggest that histones participate in a cascade of events associated with phenotypic alterations in the liver after injury.

CD14-dependent regulation of Grp78 in the liver and lungs of mice after burn injury

Recent reports have suggested that interactions between the lipopolysaccharide receptor CD14 and heat shock proteins (Hsps) play roles in proinflammatory responses. The involvement of glucose-regulated protein 78 (Grp78), a member of Hsp70 family, and CD14 in signaling events activated in the liver and lungs of mice after burn injury was investigated. Differential induction of Grp78 in the liver of CD14 knockout (KO) mice after 18% total body surface area burn was associated with a transient down-regulation of serum glucose level at day 1 after injury. Subsequent studies revealed that the liver of both CD14 KO and wild-type control mice had a significant induction of Grp78 mRNA at day 1 after injury, while the level of induction was greater in CD14 KO mice. In contrast, in the lungs, there was an up-regulation of Grp78 mRNA only in CD14 KO mice at day 1 after injury. Interestingly, both the liver and the lungs had no apparent changes in Grp78 protein expression after injury. These data demonstrate CD14-dependent and tissue-specific regulation of the Grp78 expression after burn injury. They also suggest potential activation of a CD14-independent signaling pathway involving Grp78 in distant organs after injury.

Car Seat Heaters: A Potential Hazard for Burns

Car seat heaters have gained popularity in America and worldwide. They offer comfort by heating the sitting surface to a soothing temperature. Several cases of heating-element malfunction resulted in burn injuries and have triggered recalls of thousands of cars by the manufacturers. We present a case of a 48-year-old patient with long-standing paraplegia who sustained third-degree burns on his buttock during the initial drive of a new car with seat heaters. Car seat heaters can cause severe burns. Patients with decreased sensation or immobility are at increased risk and should not use car seat heaters. This case illustrates the need for design modifications and consumer education regarding the risks associated with car seat heaters.

Predisposing Factors for Self-inflicted Burns

Self-inflicted burn injuries, although uncommon, are a significant source of morbidity and mortality. The purpose of this study was to delineate the characteristics of these burns and to examine their impact on society. Records of 32 adult patients admitted for self-inflicted burns at our regional burn center between January 1996 and August 2001 were retrospectively reviewed. The mean burn size was 34 +/- 29% TBSA, with the majority of burns being the result of self-immolation using a flammable liquid. There was a slight male predominance (59%) and a significant mortality rate (25%). Ninety-one percent of patients had an active psychiatric diagnosis, with 47% having had a previous suicide attempt. Two thirds had a chronic stressor, such as a chronic medical illness and/or long-term disability. Only four patients had private insurance, whereas the remainder relied on underfunded state- and county-sponsored programs or were uninsured. In addition to well-described psychiatric factors, common characteristics predisposing to self-inflicted burns include chronic medical illnesses, long-term disability, and a lack of access to adequate mental health care. Better treatment of mental illness in the underfunded population might ultimately save the high costs of these burn injuries.

Playing with fire: images of fire on toy packaging

Despite prevention efforts designed to teach children that fire is not a toy, each year hundreds of children, primarily male, are injured while playing with fire. Mass-produced toys and games shape children's behaviors, and the fire images on toy packaging may send the message that fire is fun rather than dangerous. The purpose of this study was to determine the frequency of male fire-related injuries at our burn center and to investigate the use of fire images in toy packaging. An aisle-by-aisle search was conducted at a national toy store. Toys with fire images on their packaging were identified. Target gender and the setting in which the fire was displayed also were recorded. Only toys with clearly visible flames on their packaging were included. We reviewed our TRACS database from April 1997 to May 1999 for fire-related injuries to children admitted to our institution as a result of playing with fire. Review of toy stores revealed 404 toys with packaging containing fire images. Of these, 97% (393 of 404) were targeted to males. Video games were the leading category of flame-related packaging (208 of 404), followed by toy car/truck displays (84 of 404). Packaging for girls' toys had safe and contained settings, whereas boys' toys used settings that were uncontrolled and associated with speed and weapons. A total of 59 children, 52 males and 7 females, with a mean age of 10 +/- 0.6 years and mean TBSA burn of 12.3 +/- 2.1% were admitted to our facility with fire-related injuries during the study interval. Children imitate life with toys and use play to experiment with new behavior. Boys are receiving a powerful, consistent message from images of fire on toy packaging. These advertisements may help to contribute to the higher incidence of fire-related injuries in boys.

The media glorifying burns: a hindrance to burn prevention

The media have a profound influence on the actions of children and adults. Burns and burn prevention tend to be ignored or even mocked. The purpose of this presentation is to reveal the callousness of the media in its dealings with burns and burn prevention. Printed materials with a relationship to burns, risk of burning, or disrespect for the consequences of burns were collected. The materials were tabulated into four categories: comics, advertisements (ads), articles that made light of burns, and television shows that portrayed behavior that would risk burn injury. Most burn-related materials were found in comics or advertisements. Several comics made light of high-risk behavior with flames, scald injury, contact injury, or burns. In addition, several advertisements showed people on fire or actions that could easily lead to burns. Several articles and televisions shows portrayed high-risk behavior that, in some instances, led to copycat injuries. Flames are frequently used to sell items that target adolescent boys or young men. The high incidence injuries that frequent this population parallel the high-risk behaviors portrayed by the media. The media portrays flames and high-risk behavior for burn injury as being cool, funny, and without consequence. The use of flames on clothing and recreational equipment (skateboards, hot rods) particularly targets the high-risk adolescent male. The burn community should make the media aware of the harm it causes with its callous depiction and glorification of burns.

Current management of purpura fulminans: a multicenter study

Seven burn centers performed a 10-yr retrospective chart review of patients diagnosed with purpura fulminans. Patient demographics, etiology, presentation, medical and surgical treatment, and outcome were reviewed. A total of 70 patients were identified. Mean patient age was 13 yr. Neisseria meningitidis was the most common etiologic agent in infants and adolescents whereas Streptococcus commonly afflicted the adult population. Acute management consisted of antibiotic administration, volume resuscitation, ventilatory and inotropic support, with occasional use of corticosteroids (38%) and protein C replacement (9%). Full-thickness skin and soft-tissue necrosis was extensive, requiring skin grafting and amputations in 90% of the patients. One fourth of the patients required amputations of all extremities. Fasciotomies when performed early appeared to limit the level of amputation in 6 of 14 patients. Therefore, fasciotomies during the initial management of these patients may reduce the depth of soft-tissue involvement and the extent of amputations.

Alterations in functional movement after axillary burn scar contracture: a motion analysis study

Children with axillary burns often develop scar contractures that restrict shoulder movement. Objective data on functional movement patterns after contracture formation is sparse. The purpose of this study was to determine how axillary contractures affect shoulder movement during activities of daily living (ADLs). This was a prospective study of children with axillary contractures scheduled for surgical release. Three-dimensional upper extremity kinematic analysis was used to assess shoulder, elbow, and trunk motion during two ADLs: high reach and hand to back pocket. Results were compared with a pool of 49 normal age-matched controls. Eleven children with axillary contractures were compared with controls. During high reach, significant decreases in shoulder flexion, shoulder internal rotation, arm pronation, and trunk extension occurred. Elbow flexion increased significantly. In the hand to back pocket task, shoulder extension and elbow flexion decreased and shoulder abduction increased. Axillary contractures result in quantifiable movement changes during ADLs. Aggressive rehabilitation is required to prevent contracture formation. Three-dimensional motion analysis is a unique tool for the quantification of functional limitations and provides an objective method to evaluate treatment efficacy in patients with axillary contractures.