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Richard L Gamelli

Publications and source records attributed to Richard L Gamelli.

At least 19 recordsLinked to original sources
PubMed2016

Early leukocyte gene expression associated with age, burn size, and inhalation injury in severely burned adults.

BACKGROUND: In the patient with burn injury, older age, larger percentage of total body surface area (TBS) burned, and inhalation injury are established risk factors for death, which typically results from multisystem organ failure and sepsis, implicating burn-induced immune dysregulation as a contributory mechanism. We sought to identify early transcriptomic changes in circulating leukocytes underlying increased mortality associated with these three risk factors. METHODS: We performed a retrospective analysis of the Glue Grant database. From 2003 to 2010, 324 adults with 20% or greater TBS burned were prospectively enrolled at five US burn centers, and 112 provided blood samples within 1 week after burn. RNA was extracted from pooled leukocytes for hybridization onto Affymetrix HU133 Plus 2.0 GeneChips. A multivariate regression model was constructed to determine risk factors for mortality. Testing for differential gene association associated with age, burn size, and inhalation injury was based on linear models using a fold change threshold of 1.5 and false discovery rate of 0.05. RESULTS: After adjusting for potential confounders, age greater than 60 years (relative risk [RR], 4.53; 95% confidence interval [CI], 2.93-6.99), burn size greater than 40% TBS (RR, 4.24; 95% CI, 2.61-6.91), and inhalation injury (RR, 2.08; 95% CI, 1.35-3.21) were independently associated with mortality. No genes were differentially expressed in association with age greater than 60 years or inhalation injury. Fifty-one probe sets representing 39 unique genes were differentially expressed in leukocytes from patients with burn size greater than 40% TBS; these genes were associated with platelet activation and degranulation/exocytosis, and gene-set enrichment analysis suggested increased cellular proliferation and down-regulation of proinflammatory cytokines. CONCLUSION: Among adults with large burns, older age, increasing burn size, and inhalation injury have a modest effect on the leukocyte transcriptome in the context of the "genomic storm" induced by a 20% or greater than TBS burned. The 39-gene signature we identified may provide novel targets for the development of therapies to reduce morbidity and mortality associated with burns greater than 40% TBS. LEVEL OF EVIDENCE: Epidemiologic study, level III.

Adult↗
PubMed2005

Reversibility of caspase activation and its role during glycochenodeoxycholate-induced hepatocyte apoptosis.

The accumulation of glycochenodeoxycholate (GCDC) induced hepatocyte apoptosis in cholestasis. However, many hepatocytes still survived GCDC-induced apoptosis. The molecular mechanism for the survival of hepatocytes remains unclear. In the present study, isolated rat hepatocytes were cultured in William's E medium and treated with 50 microM GCDC. DNA, RNA, cell lysate, and nuclear proteins were collected at different intervals for DNA fragmentation assay, reverse transcription PCR, Western blotting, and gel mobility shift assay, respectively. GCDC-induced active caspases were detected as early as 2 h by Western blotting and kinetic caspase assay, whereas hepatocyte apoptosis was found at 4 h by DNA fragmentation and terminal deoxynucleotidyl transferase-mediated dUPT nick-end labeling assay. When GCDC was removed, the increased caspases as well as NF-kappaB could be restored to control level. A1/Bfl-1 and inducible nitric oxide synthase (iNOS) were up-regulated in 2 h of GCDC stimulation. After GCDC was removed, hepatocytes decreased expression of A1/Bfl-1, but not iNOS, to the control level. NF-kappaB activation coincided with the change of A1/Bfl-1. Survivin, cIAP1, cIAP2, XIAP, and A1/Bfl-1, but not iNOS, were down-regulated by pan-caspase inhibitor benzyloxycarbonyl-VAD-fluoromethyl ketone. In addition, benzyloxycarbonyl-VAD-fluoromethyl ketone inhibited release of cytochrome c and suppressed NF-kappaB activation. Our data suggested that caspase pathway is an important regulatory factor during hepatocyte apoptosis. GCDC-induced caspase response is reversible, which may activate anti-apoptotic genes to protect hepatocytes from apoptosis.

Amino Acid Chloromethyl Ketones↗
PubMed2005

Corticosterone suppresses mesenteric lymph node T cells by inhibiting p38/ERK pathway and promotes bacterial translocation after alcohol and burn injury.

Previous studies showed that alcohol (EtOH) intoxication before burn injury suppresses mesenteric lymph node (MLN) T cell functions and increases gut bacterial translocation. In this study, we examined whether corticosterone (Cort) plays any role in suppressing MLN T cell function and bacterial accumulation after EtOH intoxication and burn injury. Rats were gavaged with EtOH to achieve a blood EtOH level of approximately 100 mg/dl before receiving 25% total body surface area burn or sham injury. A group of rats was treated with the Cort synthesis inhibitor metyrapone (25 mg/kg) at the time of injury and on day 1 after injury. Two days after injury, a significant increase in blood Cort levels and suppression of MLN T cell proliferation and IL-2 production was observed in rats receiving combined insult of EtOH intoxication and burn injury compared with rats receiving EtOH intoxication or burn injury alone. There was no change in T cell apoptosis after combined insult of EtOH and burn injury. Furthermore, T cell suppression was accompanied by a significant decrease in p38 and ERK1/2 activation (phosphorylation). There was no difference in JNK activation after EtOH and burn injury. Treatment of rats with metyrapone prevented the suppression of MLN T cell proliferation, IL-2 production, and p38 and ERK1/2 phosphorylation. Restoration of T cell function in metyrapone-treated animals was also associated with the decrease in bacterial accumulation in MLN. These findings suggest that EtOH intoxication before burn injury augments Cort release, which suppresses MLN T cell function by inhibiting p38 and ERK1/2 activation and promotes bacterial accumulation in MLN after EtOH and burn injury.

Alcoholic Intoxication↗
PubMed2005

Effect of acute alcohol ingestion prior to burn injury on intestinal bacterial growth and barrier function.

Previous studies from our laboratory have shown that acute alcohol (EtOH) ingestion prior to burn injury enhances intestinal bacterial translocation. This study tested if increased intestinal bacterial translocation in alcohol and burn injured rats is due to an overgrowth in intestinal bacteria. We determined if the translocation was accompanied with alterations in intestinal permeability and immune cell population. Rats (225-250 g) were gavaged with alcohol to achieve a blood EtOH level in the range of 100 mg/dl prior to burn or sham injury (25% total body surface area). Two days after injury, we found that acute alcohol ingestions prior to burn injury results in a significant increase in bacterial counts in small intestine. The increase in intestinal bacterial counts accompanied a significant increase in intestinal permeability. Finally, immunohistochemical analysis revealed a substantial (p<0.05) loss of both T cell and dendritic cells in intestine of alcohol and burn injured rats compared with intestine of rats receiving either burn or sham injury. Altogether, results presented in this manuscript suggest that increase in intestinal bacterial growth along with alterations in intestinal permeability and immune status contribute to the increase in bacterial translocation observed in alcohol and burn injured rats.

Animals↗
PubMed2005

The evolving characteristics and care of necrotizing soft-tissue infections.

BACKGROUND: Necrotizing soft-tissue infections such as necrotizing fasciitis and Fournier's gangrene are a source of high morbidity and mortality. These difficult cases are increasingly being referred to burn centers for specialized wound and critical care issues. In this study, we examine our institution's recent experience with a large series of necrotizing soft-tissue infections. STUDY DESIGN: A retrospective chart review was performed of 65 consecutive patients over a 5-year period with necrotizing soft-tissue infections that required radical surgical debridement. RESULTS: Overall survival was 83%, with an average length of stay of 32.4+/-3.32 days for survivors and for the entire group of 29.5+/-3 days. Time from onset of symptoms to initial presentation to our institution averaged 6.9+/-1.19 days. Patients averaged 2.9+/-0.22 surgical procedures, and 46% of patients required skin grafting with an average graft area of 1554+/-248 cm(2). Of the survivors, only 54% were able to return home, with 46% needing further hospitalization or transfer to an inpatient rehabilitation facility. CONCLUSIONS: There were frequent delays in diagnosis and referrals to and from within our institution, and progress can be made in educating the medical community to identify these patients. Advancements in wound care and critical care have made inroads into the treatment of patients with necrotizing soft-tissue infections. However, these infections continue to be a source of high morbidity and mortality and significant healthcare resource consumption. These challenging patients are best served with prompt diagnosis, immediate radical surgical debridement, and aggressive critical care management. Referral to a major burn center may help provide optimal surgical intervention, wound care, and critical care management.

Adult↗
PubMed2005

Establishing transfusion needs in burn patients.

BACKGROUND: Despite blood-conservation techniques, hemorrhage during burn excision remains substantial. It is difficult to predict the blood loss that will occur per operation and how many units the patient will require during surgery. This may result in high cross-match-to-transfusion ratios (CMTRs). METHODS: A retrospective chart review from 2001 to 2003 was performed. All adult patients with >20% total body surface area burns who underwent surgery were included in the study. Variables examined were centimeters excised, estimated blood loss, packed red blood cells transfused during surgery, preoperative and postoperative hematocrit, and CMTR. RESULTS: There were 273 operations. The average estimated blood loss was 820 mL, and; the median posttransfusion hematocrit was 27. Based on the area excised and units transfused, a ratio of packed red blood cells/cm excised was determined. A total of 1.78 U blood were transfused/1000 cm(2) excised to keep hematocrit between 25 and 31; P = 0.02. CONCLUSIONS: Estimation of excision area can predict transfusion need, which at our institution yields a low CMTR.

Adolescent↗
PubMed2005

Half-a-dozen ribs: the breakpoint for mortality.

BACKGROUND: We hypothesized that the number of rib fractures independently impacted patient pulmonary morbidity and mortality. METHODS: The National Trauma Data Bank (NTDB, v. 3.0 American College of Surgeons, Chicago, IL) was queried for patients sustaining 1 or more rib fractures. Data abstracted included the number of rib fractures by International Classification of Diseases-9 code, Injury Severity Score, the occurrence of pneumonia, acute respiratory distress syndrome, pulmonary embolus, pneumothorax, aspiration pneumonia, empyema, and associated injuries by abbreviated injury score, the need for mechanical ventilation, number of ventilator days, intensive care unit (ICU) length of stay (LOS), hospital LOS, mortality, and use of epidural analgesia. Statistical analysis was performed using the Student t test and linear regression analysis. Statistical significance was defined as a P value of less than .05. RESULTS: The NTDB included 731,823 patients. Of these, 64,750 (9%) had a diagnosis of 1 or more fractured ribs. Thirteen percent (n = 8,473) of those with rib fractures developed 13,086 complications, of which 6,292 (48%) were related to a chest-wall injury. Mechanical ventilation was required in 60% of patients for an average of 13 days. Hospital LOS averaged 7 days and ICU LOS averaged 4 days. The overall mortality rate for patients with rib fractures was 10%. The mortality rate increased (P < .02) for each additional rib fracture. The same pattern was seen for the following morbidities: pneumonia (P < .01), acute respiratory distress syndrome (P < .01), pneumothorax (P < .01), aspiration pneumonia (P < .01), empyema (P < .04), ICU LOS (P < .01), and hospital LOS for up to 7 rib fractures (P < .01). An association between increasing hospital LOS and number of rib fractures was not shown (P = .19). Pulmonary embolism also was not related to the number of rib fractures (P = .06). Epidural analgesia was used in 2.2% (n = 1,295) of patients with rib fractures. A reduction in mortality with epidural analgesia was shown at 2, 4, and 6 through 8 rib fractures. The use of epidural analgesia had no impact on the frequency of pulmonary complications. When stratifying data by Injury Severity Score and the presence or absence of rib fractures the mortality rates were similar. CONCLUSIONS: Increasing the number of rib fractures correlated directly with increasing pulmonary morbidity and mortality. Patients sustaining fractures of 6 or more ribs are at significant risk for death from causes unrelated to the rib fractures. Epidural analgesia was associated with a reduction in mortality for all patients sustaining rib fractures, particularly those with more than 4 fractures, but this modality of treatment appears to be underused.

Anesthesia, Epidural↗
PubMed2005

Neurosurgical coverage: essential, desired, or irrelevant for good patient care and trauma center status.

SUMMARY AND BACKGROUND DATA: As a result of many factors, the availability of neurosurgeons (NS) to care for trauma patients (TP) is increasingly sparse. This has precipitated a crisis in access to neurosurgical support in many trauma systems, often placing undue burden on level I centers. This study examines the profile of head-injured (HI) trauma patients and their actual need for the specific expertise of a neurosurgeon. METHODS: The National Trauma Data Bank (NTDB) was queried for specific information relating to the volume, nature, timeliness, and outcome of HI TP. Study patients were identified by reported International Classification of Diseases, 9th Edition (ICD-9) codes denoting open (OHI) or closed head injury (CHI) in isolation or in combination with other injuries. RESULTS: Total number of NTDB patients studied was 731,823, of which 213,357 (29%) had a reported HI. CHI represented 22% of all TP and 74% of HI. OHI was reported in 8% of all TP and was 26% of HI. Craniotomy (crani) was performed in 3.6% of all HI (1% of all TP). This was in 2.8% of OHI and 2.6% of CHI. Mean Glasgow Coma Scale score (GCS) of crani patients was 9, and 13 for the noncrani group. Subdural hematoma occurred in 18% of HI (5% of TP), with 13% undergoing crani. Epidural hematoma occurred in 10% of HI (3% of all TP), with 17% undergoing crani. Median time to OR for all cranis was 195 minutes (195 for CHI; 183 for OHI). Of all cranis, 6.5% were performed within 1 hour of hospital admission. Intracranial pressure (ICP) monitoring was reportedly used in 0.7% of TP and 2.2% of HI. CONCLUSIONS: Care of TP with HI rarely requires the explicit expertise and immediate presence of a neurosurgeon due to volume and nature of care. HI was diagnosed in <30% of TP reported to the NTDB. Over 95% required nonoperative management alone, with only 1% of all TP and 2%-4% of HI TP requiring crani and/or ICP monitoring. Immediate availability of NS is not essential if a properly trained and credentialed trauma surgeon or other health care provider can appropriately monitor patients for neurologic demise and effect early transfer to a center capable of, and committed to, operative and postoperative neurosurgical care. A subgroup of patients known to have a high propensity for the specific expertise of a neurosurgeon may be able to be identified for direct transport to these committed centers.

Craniocerebral Trauma↗
PubMed2005

Old fashion clinical judgment in the era of protocols: is mandatory chest X-ray necessary in injured patients?

BACKGROUND: The ATLS Course advocates that injured patients have a chest x-ray (CXR) to identify potential injuries. The purpose of this study was to correlate clinical indications and clinician judgment with CXR results to ascertain if a selective policy would be beneficial. METHODS: Patients treated at a Level I trauma center over 12 months were prospectively evaluated. Before obtaining a CXR, signs, symptoms, and history suggestive of thoracic injury were identified. Additionally, a trauma surgeon (TS) recorded whether in their judgment a CXR was clinically indicated. These findings were compared with final CXR diagnoses. The sensitivity of individual clinical indicators, combinations of clinical indicators, and TS judgment for CXR abnormalities were calculated with a 95% confidence interval. RESULTS: During the twelve-month study period, data were acquired on 772 patients (age 0-102 years). Seventy percent were male and 86.0% were injured by blunt force. Only 29% (N = 222) of the patients manifested one or more of the clinical indicators (signs and symptoms). The negative predictive value for the TS judgment was 98.2% which was superior to the clinical indicators. Reliance on the opinion of the TS to determine the need for a CXR would have eliminated 49.9% of CXRs and avoided hospital and radiologist reading charges totaling $100,078.22. CONCLUSION: Mandatory CXR for all trauma patients has a low yield for abnormal findings. A selective policy relying on surgical judgment guided by clinical indicators is safe and efficacious while reducing cost and conserving resources.

Accidental Falls↗
PubMed2004

Impaired intestinal immunity and barrier function: a cause for enhanced bacterial translocation in alcohol intoxication and burn injury.

Alcohol intoxication is being recognized increasingly as the major factor in pathogenesis after burn injury. Findings from multiple studies support the suggestion that, in comparison with burn-injured patients who sustained injury in the absence of alcohol intoxication, burn-injured patients who sustained injury under the influence of alcohol exhibit higher rates of infection and are more likely to die. Thus, infection becomes the primary cause of death in burn-injured patients. Because the intestine is considered to be a major source of bacteria, studies in experimental animals have been designed to examine whether alcohol intoxication before burn injury enhances bacterial translocation from the intestine. Results of these studies have shown a several-fold increase in bacterial translocation from the intestine in the group of animals receiving combined insult of alcohol intoxication and burn injury compared with findings for the groups receiving either insult alone. Alcohol intoxication and burn injury independent of each other have also been shown to cause an increase in bacterial translocation. The gastrointestinal tract normally maintains a physical mucosal and immunologic barrier that provides an effective defense in keeping bacteria within the intestinal lumen. However, in injury conditions these defense mechanisms are impaired. Intestinal bacteria consequently gain access to extraintestinal sites. Intestine-derived bacteria are implicated in causing systemic infection and in subsequent multiple organ dysfunction in both immunocompromised patients and patients with injury, such as burn and trauma. In this article, we discuss three potential mechanisms that are likely to contribute to the increase in bacterial translocation in alcohol intoxication and burn injury: (1) increase in bacterial growth in the intestine, (2) physical disruption of mucosal barrier of the intestine, and (3) suppression of the immune defense in the intestine.

Alcoholic Intoxication↗
PubMed2004

Medical student electives in general surgical subspecialties.

BACKGROUND: The purpose of the study was to evaluate how well the burn, trauma, and peripheral vascular third-year medical school electives meet the objectives of the six ACGME core competencies. METHODS: Medical school graduates from 1999 to 2002 completed a survey that consisted of 13 demographic/miscellaneous questions, and 28 core competency questions. RESULTS: In all, 168 of 500 students responded for a 34% response rate. All three general surgical electives ranked above average in meeting objectives in the areas of: basic science, performing complete histories and physicals, writing logical and legible notes, creating complete assessments and plan, making decisions with evidence based medicine, performing basic procedures, interpreting test results, and maintaining professional attitudes. The burn elective ranked significantly higher in 16 of 28 objectives (P < 0.05) and the trauma elective ranked significantly higher in two of 28 objectives (P < 0.05). CONCLUSIONS: Despite a narrower professional focus, three general surgical subspecialty electives meet objectives in five of the six competencies set forth by the ACGME (and adopted by our medical school as objectives for the ideal graduate). The highly organized and structured burn elective can be used as a template for improving all surgical rotations to meet the six core competencies for third-year students.

Adult↗
PubMed2004

Protection against concanavalin A-induced hepatocyte apoptosis by molsidomine is time-dependent.

BACKGROUND: Viral hepatitis and autoimmune liver diseases cause hepatocyte apoptosis. Concanavalin A (Con A)-induced hepatitis resembles human viral hepatitis and autoimmune hepatitis. The role of nitric oxide (NO) in liver injury was controversial in different liver injury models. We hypothesize both endogenous and exogenous NO protect liver against Con A-induced liver injury. Molsidomine is metabolized into SIN-1 by the liver, and SIN-1 subsequently generates NO. So, molsidomine was used as a NO donor in this study. STUDY DESIGN: To study a protective role of endogenous NO in Con A-induced liver injury, mice were pretreated with a specific inducible nitric oxide synthase (iNOS) inhibitor, L-N(6)-(1-iminoethyl)-lysine (L-NIL), before Con A challenge. To study a time-dependent protection against Con A-induced liver injury, animals were either given molsidomine, a NO donor, before or after Con A administration. Serum alanine aminotranferase (ALT) was analyzed. Liver samples were subjected to DNA fragmentation assay, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling stain, Western blot analysis, and caspase activity assays. RESULTS: Animals pretreated with L-NIL had significantly increased serum ALT levels compared with those challenged with Con A alone; but pretreatment with molsidomine dramatically decreased ALT levels in L-NIL-pretreated animals or in animals that received Con A alone. Administration of molsidomine 30 minutes before or 1, 2, and 3 hours after Con A injection significantly reduced serum ALT levels and attenuated hepatocyte apoptosis from caspase inactivation. The ALT reduction was associated with inhibition of both caspase-3 and caspase-8 activation and reduction of hepatocyte apoptosis. CONCLUSIONS: Endogenous NO plays an important protective role against Con A-induced liver injury by reducing hepatocyte apoptosis. Administration of a NO donor early after Con A injection protects the liver from injury. This is the first study demonstrating a time-dependent inhibition of liver injury induced by Con A administration.

Alanine Transaminase↗
PubMed2004

Combined alcohol and burn injury differentially regulate P-38 and ERK activation in mesenteric lymph node T cell.

Recent studies from our laboratory have suggested that acute alcohol ingestion prior to burn injury enhances gut bacterial translocation by suppressing T cell-mediated intestinal immune defense. To determine the mechanism responsible for suppressed T cell function, we examined the activation of mitogen-activated protein kinases (MAPK) members p-38 and ERK-1/2. Both p-38 and ERK-1/2 are known to play a significant role in the T cell proliferation and their cytokine production. Rats were gavaged with ethanol to achieve a blood alcohol level of approximately 100 mg/dl, before they were subjected to a 25% total body surface area burn injury. Two days after injury, rats were sacrificed and mesenteric lymph node (MLN) T cells were isolated and their ability to proliferate in response to anti-CD3 was determined. For p-38 and ERK-1/2 determination, T cells were divided into two groups. Cells in one group were stimulated with anti-CD3 for 3 min and lysed. The cells in the second group were cultured for approximately 18 h in the presence of anti-CD3 and lysed. MAPK status in 18-h cultured cells allowed us to determine whether or not the changes in p-38 and ERK-1/2 are transient or persist in the proliferating cells. Two days after injury, anti-CD3-mediated MLN T cell proliferation was more suppressed in rats gavaged with alcohol prior to burn injury compared to rats receiving either burn injury alone or sham-injured rats regardless of their exposure. Western blot analyses showed significant inhibition of ERK-1/2 phosphorylation in both freshly isolated and 18-h cultured T cells from alcohol and burn-injured rats compared to the sham rat T cells. The inhibition of p-38 phosphorylation in T cells derived from alcohol and burn-injured rats was found to be transient as no significant difference in p-38 phosphorylation was noted between the 18 h incubated MLN T cells of sham and alcohol and burn-injured rats. Taken together, our findings suggest that low levels of ERK-1/2 activation is likely to play a significant role in MLN T cell proliferative suppression in alcohol and burn-injured rats.

Animals↗
PubMed2004

Exacerbation of intestinal permeability in rats after a two-hit injury: burn and Enterococcus faecalis infection.

OBJECTIVE: To determine alterations in intestinal epithelial permeability to solutes in burn injured rats with and without Enterococcus faecalis infection and the role of neutrophils in the intestinal permeability changes. DESIGN: Prospective sham-controlled animal study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Rats were subjected to 30% total body surface burn (B group), E. faecalis infection (EF group) induced via intra-abdominal implantation of bacterial pellet, or combination of burn injury and E. faecalis infection (B+EF group). MEASUREMENTS AND MAIN RESULTS: In vivo measurements of intestinal permeability were carried out after intraluminal injection of H lactulose and C mannitol in the ileum of sham, B, EF, and B+EF groups of rats, 1 and 2 days after injury. Lactulose permeability was increased in the injured rat groups (B, EF, B+EF) on day 1 postinjury compared with sham. The combined injury group (B+EF) had the highest level of lactulose permeability. Although a significant change in lactulose permeability from day 1 to day 2 postinjury could not be demonstrated in the B and EF groups, lactulose permeability in the B+EF group on day 2 postinjury markedly decreased from day 1 but was still significantly higher than that in the sham group. Mannitol permeability was increased in all injured rat groups on day 1 postinjury; on day 2 it remained elevated post-B, decreased post-EF, and further increased after B+EF. Ex vivo measurements of lactulose movements across intestinal epithelial monolayers (IEC-18) were carried out in the presence of blood neutrophils from sham, B, EF, or B+EF rats. We also measured ex vivo transepithelial migration of neutrophils from sham, B, EF, or B+EF rat groups. Neither the transepithelial lactulose movement in the presence of neutrophils from, nor neutrophil migration in, the B or EF rats was significantly different from sham. However, a significant increase in transepithelial lactulose movement and neutrophil migration occurred in the B+EF group. Immunoblot analyses and in situ histochemical localizations of intestinal tight junction proteins, occludin and claudin-3, showed decreases in the distribution of occludin but not claudin-3 in the B, EF, and B+EF groups. CONCLUSIONS: Alterations in intestinal solute permeability and disruption of tight junction integrity after a two-hit injury with burn and E. faecalis infection, but not after individual injuries of burn or E. faecalis infection, are likely associated with heightened neutrophil flux across the intestinal epithelium.

Animals↗
PubMed2004

Bone marrow norepinephrine mediates development of functionally different macrophages after thermal injury and sepsis.

OBJECTIVE: We sought to determine the influence of thermal (burn) injury with sepsis and norepinephrine on the clonogenic potential and functional cytokine response to lipopolysaccharide (LPS) stimulation in nonmyeloid committed (CD117) and myeloid committed (ER-MP12) bone marrow progenitor cells. SUMMARY AND BACKGROUND DATA: We have previously demonstrated that norepinephrine stimulated myelopoiesis after burn injury and sepsis, but the site of this stimulation in monocyte development is unknown. In the present study the influence of norepinephrine on the developmental hierarchy of bone marrow cells after thermal injury and sepsis was determined by assessing the clonogenic potential and LPS-stimulated cytokine responses of mature macrophages derived from CD117 and ER-MP12 bone marrow progenitor cells. METHODS: Tissue and bone marrow norepinephrine content was ablated by chemical sympathectomy with 6-hydroxydopamine treatment. CD117 and ER-MP12 bone marrow cells were isolated using antibody-linked magnetic microbeads. Clonogenic potential in response to colony-stimulating factors was determined. Both progenitor cell types were differentiated to mature macrophages in vitro and tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 cytokine responses to LPS provocation were determined. RESULTS: The macrophage- and granulocyte-macrophage colony-stimulating factor responsive clonogenic potential was increased with burn sepsis, suggesting an expansion of both progenitor populations. Such increases were greatly reduced with prior depletion of norepinephrine. TNF-alpha and IL-6 cytokine responses to LPS were markedly influenced by the specific progenitor cells involved as well as the injury conditions and the status of norepinephrine prior to injury. In burn sepsis the depletion of norepinephrine resulted in a dramatic decrease in both IL-6 and TNF-alpha production by both progenitor-derived macrophages. CONCLUSIONS: Depletion of norepinephrine attenuated burn and burn sepsis-induced bone marrow progenitor clonal growth in response to macrophage- and granulocyte-macrophage colony-stimulating factor. Functional phenotypes of bone marrow progenitor-derived macrophages are greatly influenced by norepinephrine and the milieu created by thermal injury and sepsis.

Animals↗
PubMed2004

Burn injury and pulmonary sepsis: development of a clinically relevant model.

BACKGROUND: Despite improvements in the early resuscitation of the critically injured, mortality from multiple organ failure has remained stable, with the lung often the first organ to fail. Early intubation and mechanical ventilation predispose patients to the development of pneumonia and respiratory failure. Our objective was to establish a murine model of combined injury, consisting of burn/trauma and pulmonary sepsis with reproducible end-organ responses and mortality. METHODS: Male B6D2F1 mice were divided into four groups: burn/infection (BI), burn (B), infection (I), and sham (S). Burned animals had a full-thickness 15% dorsal scald burn. BI and I groups were inoculated intratracheally with Pseudomonas aeruginosa (3-5 x 103 colony-forming units). S and B animals received saline intratracheally. All animals were resuscitated with 2 mL of intraperitoneal saline. Mortality was recorded at 24, 48, and 72 hours. Bacterial sepsis was confirmed by tissue Gram's stain of the lungs and positive organ and blood cultures for Pseudomonas aeruginosa. Femoral bone marrow cells were collected at 72 hours from surviving animals. Clonogenic potential was assessed by response to macrophage (M) colony-stimulating factor (CSF) and granulocyte-macrophage (GM) CSF in a soft agar assay and the data were represented as colonies per femur. Isolated alveolar macrophages and whole lung tissue were assayed for levels of the inflammatory cytokines tumor necrosis factor-alpha and interleukin-6. RESULTS: Mortality at 72 hours was 30% in BI, 12% in I, and <10% in B and S groups. Pneumonia was documented in all infected animals at 24 hours by Gram's stain and positive tissue cultures for Pseudomonas aeruginosa. Systemic sepsis as confirmed by blood, and remote organ cultures was seen in BI animals only. Significantly increased responsiveness to M-CSF stimulations was noted in all groups (BI, 8,291 +/- 1,402 colonies/femur; B, 6,357 +/- 806 colonies/femur; and I, 8,054 +/- 1,112 colonies/femur; p < 0.05) relative to sham (3,369 +/- 883 colonies/femur, p < 0.05). Maximal responsiveness to GM-CSF stimulation was noted in the BI group (11,932 +/- 982 colonies/femur, p < 0.05), and similar GM responsiveness was noted in all other groups (B, 7,135 +/- 548 colonies/femur; I, 7,023 +/- 810 colonies/femur; and S, 6,829 +/- 1,439 colonies/femur). Alveolar macrophage release of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-6 increased in all animals, but the magnitude of increase was not proportional to the strength of the inciting stimulus. CONCLUSION: Although minimal perturbations were seen after burn or pulmonary infection alone, the combined insult of burn and pulmonary sepsis resulted in statistically significant hematopoietic changes with increased monocytopoiesis. Only the combined injury resulted in systemic sepsis and significantly increased mortality. We have developed a clinically relevant model of trauma and pulmonary sepsis that will allow further clarification of the inflammatory response after injury and infection.

Animals↗
PubMed2004

Ten year experience of burn, trauma, and combined burn/trauma injuries comparing outcomes.

BACKGROUND: Percent total body surface area (TBSA) burn, inhalation injury (INH), and age all have been shown to be independent predictors of mortality in burn victims. Little is known regarding patients sustaining combined thermal and mechanical injuries in relation to either injury sustained in isolation or with regard to these variables. This descriptive study profiles the 10-year experience of a single American Burn Association/American College of Surgeons verified Level I trauma and burn center and the treatment of this patient population. METHODS: A retrospective review of all burn and trauma patients admitted between 1990 and 2000. Patients were divided into three groups; Burn only (B), Trauma only (T), and combined Burn/Trauma (B/T). Groups were compared with respect to age, TBSA burn, length of stay (LOS), Injury Severity Score (ISS), INH and mortality. These groups were then compared with B, T and B/T patients from the National Burn Repository (NBR) and National Trauma Data Bank (NTDB). Student's t test and chi tests were performed, as well as multiple logistic regression to identify independent predictors of mortality. p <0.05 was considered significant. RESULTS: Through our trauma registry, 24,093 patients were identified (T=22,284, B=1717 and B/T=92). When comparing B and T, there was no difference in age, LOS, ISS, or mortality to those patients in the NBR or NTDB. B/T patients showed significantly increased percentage with INH (B/T=44.5% versus 11%), increased LOS (B/T=18 days versus 13.7 B and 5.3 T) and increased mortality (B/T=28.3% versus 9.8% B and 4.3% T). B/T were also significantly older (B/T=40.1 years versus 31.0 B and 35.1 T). When these variables are compared with the NBR and the NTDB benchmarks, mortality (28.3% versus 11.6% NBR and 7.0% NTDB) and ISS (23 versus 11.7 NTDB) were significantly higher with no difference in age (40.1 versus 33.4 NTDB, 35.9 NBR), LOS (18 days versus 23.3 NBR) or TBSA (20.8% versus 19.5% NBR). Multiple logistic regression comparing TBSA, age, ISS and INH of survivors versus non-survivors identified only ISS as an independent predictor of mortality. CONCLUSION: B combined with T presents a rare injury pattern that has a synergistic effect on mortality. Physicians and caregivers should be aware of a 2-3 fold increase in the incidence of INH in this population, and increased mortality despite similar TBSA burned when compared with patients with B as the sole mechanism; ISS appears to be an independent predictor of mortality in this combined injury pattern.

Adolescent↗