Oxidative-induced calcium mobilization is dependent on annexin VI release from lipid rafts

BACKGROUND

Oxidative stress results in macrophage reprogramming through the formation of focal adhesion-like complexes on lipid rafts. Although the cellular mechanisms responsible for this reprogramming remain unknown, oxidative stress is known to result in a transient increase in intracellular calcium. This transient flux is thought to occur through the membrane dissociation of the calcium-bound protein annexin VI. The purpose of this study is to clarify the source of the calcium, and determine if it is responsible for the formation of focal adhesion-like complexes during oxidative stress through the activation of calcium/calmodulin dependent protein kinase II (CaMK II).

METHODS

THP-1 cells were stimulated with hydrogen peroxide. Selected cells were pretreated with methyl beta-cyclodextrin (MbetaCD), a cholesterol-depleting agent; 1,2-bis aminophenoxy ethane-N,N,N',N'-tetraacetic acid, an intracellular calcium chelator; or autocamtide 2-related inhibitory peptide, a CaMK II inhibitor. Intracellular calcium flux was determined by a Fluo-3 technique. Lipid raft and cellular protein were extracted and analyzed for active CaMK II, annexin VI, and components of focal adhesion-like complexes.

RESULTS

Hydrogen peroxide exposure led to mobilization of annexin VI from lipid rafts to the cytosol, which was followed by an increase in cytosolic calcium, phosphorylation of CaMK II, and formation of focal adhesion-like complexes. Cholesterol depletion from lipid rafts attenuated all of these effects. 1,2-bis Aminophenoxy ethane-N,N,N',N'-tetraacetic acid and autocamtide 2-related inhibitory peptide pretreatment attenuated CaMK II phopshorylation and formation of focal ahdesionlike complexes.

CONCLUSIONS

Macrophage reprogramming during oxidative stress occurs through the cytosolic mobilization of annexin VI from lipid rafts. As a result, bound calcium dissociates, resulting in the activation of CaMK II and the formation of focal adhesion-like complexes.

Whole blood and leukocyte RNA isolation for gene expression analyses

The analysis of gene expression data in clinical medicine has been plagued by the lack of a critical evaluation of accepted methodologies for the collection, processing, and labeling of RNA. In the present report, the reliability of two commonly used techniques to isolate RNA from whole blood or its leukocyte compartment was compared by examining their reproducibility, variance, and signal-to-noise ratios. Whole blood was obtained from healthy subjects and was either untreated or stimulated ex vivo with Staphylococcus enterotoxin B (SEB). Blood samples were also obtained from trauma patients but were not stimulated with SEB ex vivo. Total RNA was isolated from whole blood with the PAXgene proprietary blood collection system or from isolated leukocytes. Biotin-labeled cRNA was hybridized to Affymetrix GeneChips. The Pearson correlation coefficient for gene expression measurements in replicates from healthy subjects with both techniques was excellent, exceeding 0.985. Unsupervised analyses, including hierarchical cluster analysis, however, revealed that the RNA isolation method resulted in greater differences in gene expression than stimulation with SEB or among different trauma patients. The intraclass correlation, a measure of signal-to-noise ratio, of the difference between SEB-stimulated and unstimulated blood from healthy subjects was significantly higher in leukocyte-derived samples than in whole blood: 0.75 vs. 0.46 (P = 0.002). At the P < 0.001 level of significance, twice as many probe sets discriminated between SEB-stimulated and unstimulated blood with leukocyte isolation than with PAXgene. The findings suggest that the method of RNA isolation from whole blood is a critical variable in the design of clinical studies using microarray analyses.

Calcium/calmodulin-dependent kinase II is required for platelet-activating factor priming

Platelet-activating factor (PAF) primes the macrophage proinflammatory response to inflammatory stimuli, such as lipopolysaccharide (LPS). The cellular events responsible for this priming or reprogramming remain unresolved, but may occur through an increase in cytosolic calcium, inducing calcium/calmodulin-dependent kinase (CaMK) activation. To study this, differentiated THP-1 cells were used to study the effect of CaMK II and IV inhibition on PAF-induced reprogramming of TLR4-mediated events. LPS induced p38, ERK 1/2, and JNK/SAPK phosphorylation, NF-kappaB and AP-1 activation, and TNF-alpha and IL-10 production. PAF pretreatment selectively increased LPS-induced ERK 1/2, JNK/SAPK, NF-kappaB and AP-1 activation, and TNF-alpha production. Inhibition of CaMK II prevented PAF-induced priming of these events. Inhibition of CaMK IV prevented LPS-induced ERK 1/2, JNK/SAPK, NF-kappaB and AP-1 activation, and TNF-alpha production, but increased IL-10 production with or without PAF pretreatment. Neither CaMK II nor IV inhibition had any affect on p38 activity. These data suggest that the function of CaMK II is essential for PAF-induced macrophage priming. This priming event is mediated in part by modulation of ERK 1/2, JNK/SAPK, NF-kappaB, and AP-1 activation. CaMK IV, on the other hand, is not specific for priming by PAF and appears to have a direct link in TLR4-mediated events.

Pathogenesis of multiple organ dysfunction syndrome--endotoxin, inflammatory cells, and their mediators: cytokines and reactive oxygen species

Multiple organ dysfunction syndrome (MODS) is caused by an overwhelming, uncontrolled systemic inflammatory response that is activated by a number of hostile stimuli including sepsis, hypovolemic shock, and severe trauma resulting in massive tissue injury. The indiscriminate activation of the inflammatory response due to these insults causes loss of the host's ability to localize the inflammation to the focus of the problem, leading to systemic inflammation and severe host tissue damage and subsequent MODS. While the major players, namely neutrophils, macrophages, endotoxin, cytokines, and oxidants have been known for some time, the disease processes responsible for the pathogenesis of MODS have only recently been elucidated. Our newly found knowledge has resulted in the development of novel therapeutic strategies to prevent or treat MODS, such as scavenging toxic oxygen species and inhibiting endotoxin, or cytokine production, or cytokine activity. Unfortunately, these strategies have not resulted in improved mortality rates among patients with MODS. The complex nature of the host response to severe insults combined with the fact that the host has multiple, redundant parallel systems to deal with various insults has made it difficult for clinical interventions to adequately ameliorate the disease process among patients at risk for MODS. The purpose of this article is to attempt to "dissect out" several individual components of the inflammatory response that play important roles in the development of MODS and to review some potentially beneficial approaches to combat these harmful processes.

The use of neuromuscular blocking agents to facilitate prehospital intubation does not impair outcome after traumatic brain injury

BACKGROUND

Several studies have demonstrated that the success rate of prehospital intubation is improved by the use of neuromuscular blocking agents (NMBAs). However, a recent study has reported that prehospital intubation with NMBAs worsens outcome after traumatic brain injury (TBI). We sought to determine the effect of the use of NMBAs to facilitate prehospital intubation on outcome after TBI.

METHODS

All patients admitted to our Level I trauma center with a head Abbreviated Injury Scale score >/= 3 were identified by the trauma registry (January 1998-June 2003). Patient records were matched with prehospital databases. Patients were further stratified on the basis of prehospital Glasgow Coma Scale (GCS) score into mild (GCS score of 14/15), moderate (GCS score of 9-13), and severe (GCS score < 9) TBI. Outcome included mortality and good outcome (survival to discharge with a GCS score of 14/15).

RESULTS

There were 3,052 patients who were identified as having been transported directly from the field. Complete prehospital data were available for 2,012 patients (66%). Of these, 920 were mild TBI (intubation rate, 17.4%), 293 moderate TBI (intubation rate, 57.7%), and 799 severe TBI (intubation rate, 95%). Overall, 72% of intubated patients received NMBAs. There were no significant differences in demographics or injury severity between the groups. Patients not receiving NMBAs were more likely to be hypotensive and have prehospital cardiopulmonary resuscitation (p = 0.001). The unadjusted mortality for the patients intubated with NMBAs was 25% versus 37% for those not receiving NMBAs (p < 0.001). When adjusted for confounding variables, patients intubated with NMBAs were more likely to survive (odds ratio, 0.63; 95% confidence interval, 0.41-0.97; p = 0.04) and have a good outcome (odds ratio, 1.7; 95% confidence interval, 1.2-2.6; p = 0.006) than those in the no-NMBA group.

CONCLUSION

The use of NMBAs to facilitate prehospital intubation improves outcome for patients with TBI. The value of prehospital intubation for TBI remains to be determined; however, any trial evaluating nonintubation for TBI must be compared with NMBA-facilitated intubation to be valid.

HYPERTONIC SALINE MODULATES INNATE IMMUNITY IN A MODEL OF SYSTEMIC INFLAMMATION

We sought to determine if hypertonic saline (HTS) impacted alveolar macrophage (AM) activation and intracellular inflammatory gene signaling in a model of systemic inflammation. Rats received an intravenous administration of 4 mL/kg of 7.5% HTS or L-lactate lactated Ringer's (L-LR). They were simultaneously treated with an intraperitoneal injection of zymosan, which induces noninfectious systemic inflammation. AM were harvested by bronchoalveolar lavage 24 h after treatment. AM activation was analyzed by measurement of baseline and lipopolysaccharide (LPS)-induced TNF-alpha production. Intracellular signaling was analyzed for activation of the mitogen-activated protein kinases (MAPKs): ERK1/2, JNK, and p38. AM from HTS-treated rats produced less TNF-alpha than from L-LR-treated rats (927 +/- 335 pg/mL [SEM] vs. 3628 +/- 783 pg/mL [SEM], P = 0.001) and were also less responsive to LPS (4444 +/- 86 pg/mL [SEM] vs. 6666 +/- 91 pg/mL [SEM], P = 0.058). However, there was no difference in MAPK activation. In vivo HTS prevents excessive AM activation during systemic inflammation. This suppression is mediated through alternate pathways and does not induce the classic MAPK signaling cascade.

Evaluation of hyaluronan from different sources: Streptococcus zooepidemicus, rooster comb, bovine vitreous, and human umbilical cord

Sodium hyaluronate (HA) is widely distributed in extracellular matrixes and can play a role in orchestrating cell function. Consequently, many investigators have looked at the effect of exogenous HA on cell behavior in vitro. HA can be isolated from several sources (e.g., bacterial, rooster comb, umbilical cord) and therefore can possess diverse impurities. This current study compares the measured impurities and the differences in biological activity between HA preparations from these sources. It was demonstrated that nucleic acid and protein content was highest in human umbilical cord and bovine vitreous HA and was low in bacterial and rooster comb HA. Macrophages exposed to human umbilical cord HA produced significantly higher amounts of TNF-alpha relative to control or bacterial-derived HA. These results indicate that the source of HA should be considered due to differences in the amounts and types of contaminants that could lead to widely different behaviors in vitro and in vivo.

Application of genome-wide expression analysis to human health and disease

The application of genome-wide expression analysis to a large-scale, multicentered program in critically ill patients poses a number of theoretical and technical challenges. We describe here an analytical and organizational approach to a systematic evaluation of the variance associated with genome-wide expression analysis specifically tailored to study human disease. We analyzed sources of variance in genome-wide expression analyses performed with commercial oligonucleotide arrays. In addition, variance in gene expression in human blood leukocytes caused by repeated sampling in the same subject, among different healthy subjects, among different leukocyte subpopulations, and the effect of traumatic injury, were also explored. We report that analytical variance caused by sample processing was acceptably small. Blood leukocyte gene expression in the same individual over a 24-h period was remarkably constant. In contrast, genome-wide expression varied significantly among different subjects and leukocyte subpopulations. Expectedly, traumatic injury induced dramatic changes in apparent gene expression that were greater in magnitude than the analytical noise and interindividual variance. We demonstrate that the development of a nation-wide program for gene expression analysis with careful attention to analytical details can reduce the variance in the clinical setting to a level where patterns of gene expression are informative among different healthy human subjects, and can be studied with confidence in human disease.

Anti-inflammatory drug delivery from hyaluronic acid hydrogels

Two different types of hyaluronic acid (HA) hydrogels were synthesized by crosslinking HA with divinyl sulfone (DVS) and poly(ethylene glycol)-divinyl sulfone (VS-PEG-VS). Vitamin E succinate (VES), an anti-inflammatory drug, and bovine serum albumin (BSA), a model of anti-inflammatory protein drugs, were loaded into the gels and their release kinetics were measured in vitro. VES and BSA released with a burst from both HA hydrogels during the first few hours, and release continued gradually for several days. The rate of release from HA-VS-PEG-VS-HA hydrogels was faster than that from HA-DVS-HA hydrogels, presumably due to the lower crosslink density in the former. The anti-inflammatory action of released VES was tested by incubating peripheral blood mononuclear cells (PBMC) on HA hydrogels with and without VES in the gel. The number of cells adhering on HA hydrogels was very low compared to that on tissue culture polystyrene (TCPS), which might be one of the important advantages of using HA hydrogels for implant coatings or tissue engineering applications. ELISA test results showed that the tumor necrosis factor-alpha (TNF-alpha) concentration was very low in the supernatant of the wells containing the HA hydrogel with VES in contact with the activated macrophages compared to that without VES. This is probably the effect of the released VES reducing the production of anti-inflammatory cytokine, TNF-alpha. HA hydrogels containing anti-inflammatory drugs may have potential for use in tissue engineering and also as biocompatible coatings of implants.

Prevention of immunization to D+ red blood cells with red blood cell exchange and intravenous Rh immune globulin

BACKGROUND

Although young women who are D- occasionally receive unintentional transfusions with D+ red blood cells (RBCs), there are little data to assist with management of such an event. Two cases of D- girls transfused with D+ RBCs are reported. In an effort to prevent formation of anti-D, RBC exchange followed by administration of intravenous (IV) Rh immune globulin (RhIg) was used.

CASE REPORTS

Patient 1, a 56-kg, 16-year-old D- girl, was involved in a motor vehicle crash. She received 4 units of Group O uncrossmatched D+ RBCs. Thirty-six hours after admission, she underwent RBC exchange with 10 units of D- RBCs, followed by a total of 2718 microg of IV RhIg over 32 hours. Six months later, her antibody screen was negative. Patient 2, a 39-kg, 10-year-old D- girl with aplastic anemia, received 1 unit of D+ RBCs. She underwent RBC exchange on the same day with 5 units of D- RBCs, followed by a total of 900 microg of IV RhIg over 8 hours. Six months later her antibody screen was negative.

CONCLUSION

RBC exchange followed by a calculated dose of IV RhIg was successful in preventing allo-immunization to D. Several small studies suggest that both trauma and hematology patients may be less capable of becoming immunized with the transfusion of D+ blood components. Until these findings are more clearly defined, there will be times when prevention of immunization of any D- girl is desired. RBC exchange followed by RhIg appears to be one way to achieve this goal.

Source control in the management of severe sepsis and septic shock: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for source control in the management of severe sepsis and septic shock that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and to improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Source control represents a key component of success in therapy of sepsis. It includes drainage of infected fluids, debridement of infected soft tissues, removal of infected devices or foreign bodies, and finally, definite measures to correct anatomic derangement resulting in ongoing microbial contamination and to restore optimal function. Although highly logical, since source control is the best way to reduce quickly the bacterial inoculum, most recommendations are, however, graded as D or E due to the difficulty to perform appropriate randomized clinical trials in this respect. Appropriate source control should be part of the systematic checklist we have to keep in mind in setting up the therapeutic strategy in sepsis.

Modulation of macrophage responsiveness to lipopolysaccharide by IRAK-1 manipulation

Local activation of the macrophage by endotoxin is essential for the eradication of invasive gram-negative infections. Circulating endotoxin at lower concentrations results in immune cell activation at distant sites leading to tissue injury. Although the cellular mechanisms involved in these potentially dissimilar events are incomplete, it appears that the proximal kinase IRAK-1 plays a role. Thus, sense and antisense IRAK-1 oligonucleotides were used to determine the role IRAK-1 plays in macrophage activation by systemic (1-100 ng/mL) and local (1000 ng/mL) concentration of lipopolysaccharide (LPS) within THP-1 cells. Within the sense group, 1-1000 ng/mL of LPS within the sense group resulted in cellular activation of ERK-1/2, p38, and JNK/SAPK and the nuclear activation of NF-kappaB and AP-1. This activation was associated with proinflammatory cytokine production and cellular spreading. Systemic concentrations of LPS within the antisense group were associated with significant attenuation of intracellular signaling, cytokine production, and cellular spreading compared with the sense group. Local concentrations of LPS within the antisense group, however, were associated only with a delay in intracellular signaling, with no effect on cytokine production or cell spreading compared with the sense group. Based on these results, it appears that IRAK-1 is essential to macrophage activation at systemic, but not local, concentrations of LPS. These data suggest that redundant pathways exist that are functional at higher concentrations of LPS. Therefore, IRAK-1 appears to be the central kinase involved in the activation of the macrophage at distant sites during septic shock but is not necessary for activation in areas of local infection.

Oxandrolone does not improve outcome of ventilator dependent surgical patients

BACKGROUND

Multisystem injury and major surgical stress result in a hypermetabolic state with accelerated breakdown of protein stores. Loss of lean muscle mass impairs wound healing, increases infection rates, and weakens respiratory musculature. Oxandrolone is an anabolic steroid that attenuates loss of lean body mass and improves wound healing in burn patients. We hypothesized that oxandrolone would improve outcome for ventilator-dependent surgical patients.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial of oxandrolone therapy for surgical/trauma patients requiring >7 days of ventilation. The primary end point was time on the ventilator.

RESULTS

Forty-one patients were enrolled between January 1, 2001, and June 15, 2003, 18 received oxandrolone (10 mg po BID) and 23 received a placebo. Groups were comparable for age, gender, injury severity score, and APACHE II score. The majority were trauma patients (83%), and 90% received enteral feeding. The oxandrolone group received higher caloric and protein intake before enrollment, but these differences were not significant. Contrary to our hypothesis, patients receiving oxandrolone spent significantly longer time on the ventilator than the placebo group (mean 21.7 days vs. 16.4 days, P = 0.03). There was no difference in infectious complications, acute respiratory distress syndrome, or multiple organ failure scores. Patients receiving oxandrolone had a longer intensive care unit stay but no difference in total hospital stay.

CONCLUSION

Ventilator-dependent surgical patients receiving oxandrolone had a more prolonged course of mechanical ventilation, suggesting that oxandrolone may be detrimental in this circumstance. Oxandrolone may enhance collagen deposition and fibrosis in the later stages of acute respiratory distress syndrome and thus prolong recovery.

Centers for Disease Control and Prevention injury research agenda: identification of acute care research topics of interest to the Centers for disease Control and Prevention--National Center for Injury Prevention and Control

BACKGROUND

The purpose of this report is to identify the most important research questions pertaining to the acute care of the injured patient using a Web-based Delphi technique to achieve expert opinion consensus.

METHODS

Experts in trauma care from the United States and Canada (n =39) generated structured research questions and then ranked these questions in order of importance, using a Web-based survey for question generation, question ranking, and a Delphi technique of consensus. Guidelines for question construction and ranking specified that participants considered questions that fall within the interest and domain of the Centers for Disease Control (CDC)-National Center for Injury Prevention and Control (NCIPC).

RESULTS

One hundred thirty-seven questions in 18 distinct categories of interest were initially generated. After two rounds of merging, collating, reassessing, and ranking by significance and importance, 25 research questions were deemed most important and significant in the care of the injured patient. Ten of these (40%) were considered to be appropriate issues for the CDC-NCIPC to address and fund, dealing with injury prevention strategies, trauma systems design and funding, the epidemiology of injury, and global outcome determinants. These 25 questions were also reviewed with consideration given to the most likely source of federal funding of investigations.

CONCLUSION

This report identifies the areas of trauma care in which research efforts might best be directed. Fully 40% of the key research questions could be considered to fall under the interest and auspices of the CDC-NCIPC. The remaining questions cover a broad range of topics and likely funding sources, emphasizing the need for a coordinated oversight of research funding in trauma care.

Development of trauma systems and effect on outcomes after injury

The ideal system for management of trauma remains controversial, especially in respect of prehospital care and regionalisation of trauma-care delivery. To explore these issues, we compare two differing trauma systems--in the USA the focus is on the trauma centre, with a lesser emphasis on prehospital care, whereas in France there is more emphasis on prehospital care coordinated by the Service d'Aide Médicale Urgente. We describe the historical developments, current structure, and major controversies with regard to trauma-care delivery in the two countries. Comparative evidence on the effectiveness of the two systems was obtained through a structured review of databases, but very little evidence permits direct comparison of outcomes across the two systems. Crude injury mortality rates and fatality rates from motor-vehicle accidents (crashes in US usage) are higher in France than in the USA, although adjustment for potential confounders is difficult. Adjusted mortality rates suggest equivalent outcomes among patients who survive to hospital, although these data are confounded by the lack of a contemporaneous comparator population. There are differences in the American and French trauma systems that might translate into measurable differences in trauma-related mortality. However, the lack of data to allow comparison of outcomes between countries significantly impedes the identification and implementation of components of a trauma system that are effective and the discarding of those that offer little benefit.

A Comparison of Prehospital and Hospital Data in Trauma Patients

OBJECTIVE

The use of prehospital data as an indicator for trauma team activation has been established. The relationship between field (Fd) and emergency department (ED) systolic blood pressure (SBP), Glasgow Coma Scale (GCS) score, and airway control as it relates to outcomes is unclear. We hypothesized that ED and Fd physiologic parameters are equally valid predictors of outcomes. In addition, we hypothesized that early field intubation will improve survival compared with later ED intubation.

METHODS

Trauma registry data from two academic Level I centers from 1994 to 2001, excluding all transfers and burn patients, were analyzed using Wilcoxon signed-rank test and multivariate logistic regression with appropriate adjustments.

RESULTS

There were 19,409 patients, 16,277 blunt and 3,132 penetrating trauma. There were 3,571 Fd and 746 ED intubations. ED intubation was associated with increased risk of fatal outcome compared with nonintubated patient (adjusted odds ratio, 3.1; p < 0.0001) and field intubations (adjusted odds ratio, 3.0; p < 0.0001). ED-GCS score was not significantly different from Fd-GCS score, with 82% having the same GCS category. This was not the case for SBP, and only in 60% of the cases were ED-SBP and Fd-SBP in the same category. In 31% of the patients, the ED-SBP increased, and in 9% of cases, the ED-SBP decreased compared with Fd-SBP. This was true for both blunt and penetrating trauma. Both Fd-SBP and ED-SBP were independent predicators of fatal outcome, and mortality rate significantly increased if ED-SBP category decreased compared with Fd-SBP.

CONCLUSION

Early field intubation was associated with a decreased risk of fatal outcome compared with ED intubation. ED-GCS score was not significantly different from Fd-GCS score, and either one can be used to predict fatal outcome. However, ED-SBP was different from Fd-SBP in 40% of the patients, with the majority of cases having higher ED-SBP. Although ED-SBP was a better predictor of outcome, the best model is achieved when both ED and field SBP are used.

Implications of proteasome inhibition: an enhanced macrophage phenotype

The objective of this study was to elucidate the role of the cellular proteasome on endotoxin-mediated activation of the macrophage. To study this role, THP-1 cells were stimulated with lipopolysaccharide (LPS) with selective cells being pretreated with the proteasome inhibitor, lactacystin or MG-132. LPS stimulation led to the phosphorylation and degradation of IRAK, followed by activation of JNK/SAPK, ERK 1/2, and p38. Subsequently, LPS induced the degradation of IkappaB, and the nuclear activation of NF-kappaB and AP-1. Activation of these pathways was associated with the production of IL-6, IL-8, IL-10, and TNF-alpha. Proteasome inhibition with either lactacystin or MG-132 attenuated LPS-induced IRAK degradation, and enhanced activation of JNK/SAPK, ERK 1/2, and p38. Proteasome inhibition, also, led to increased LPS-induced AP-1 activation, and attenuated LPS-induced IkappaB degradation resulting in abolished NF-kappaB activation. Proteasome inhibition led to significant modulation of LPS-induced cytokine production; increased IL-10, no change in IL-6, and decreased IL-8, and TNF-alpha. Thus, this study demonstrates that cellular proteasome is critical to regulation of LPS-induced signaling within the macrophage, and inhibition of the proteasome results in a conversion to an anti-inflammatory phenotype.

Causalgia: a meta-analysis of the literature

BACKGROUND

Causalgia is not familiar to most physicians whose training and experience are limited to civilian practice.

HYPOTHESIS

Through a thorough review of the literature, we attempted to determine the boundaries of causalgia and separate it from other sympathetically related disorders.

DATA SOURCES

Database search for English-language articles in MEDLINE and Index Medicus up to the year 2000 as both keyword and subject under causalgia.

STUDY SELECTION

References that described any new cases referred to as "causalgia" by their authors were included in a meta-analysis.

DATA SYNTHESIS

One hundred ten articles contained a total of 1528 cases of causalgia. High-velocity missiles caused at least 77% of the injuries. In 72% and 90% of the cases reported, the time from injury to onset of pain was within 1 week and 1 month, respectively. Median nerve alone or in combination with other nerves (56%) and sciatic trunk injury (60%) were the most common nerves involved. In 92%, the nerve injury was incomplete. The most prominent clinical manifestations included burning pain in 86%, increased sweating in 73%, relief with application of cold in 62%, warmth in 50%, paresthesias in 96%, absence of anesthesia in 81%, and sensitivity to stimuli in 98%. Response to sympathetic blocks was observed in 88%. Finally, a total of 94% of the patients undergoing sympathectomy were cured.

CONCLUSIONS

Cases of causalgia are easy to recognize and treat, with excellent results. Causalgia always follows a somatic nerve injury, usually partial, and is associated with near-constant, very severe pain distal to the injury in the extremity, varied in nature but characteristically with a predominantly burning quality. An effective anesthetic block of the appropriate part of the sympathetic chain frequently immediately relieves the pain. Most cases are cured by surgical sympathectomy.

Effects of adsorbed proteins and surface chemistry on foreign body giant cell formation, tumor necrosis factor alpha release and procoagulant activity of monocytes

The adhesion and activation of monocytes and macrophages are thought to affect the foreign body response to implanted medical devices. However, these cells interact with devices indirectly, because of the prior adsorption of proteins. Therefore, we preadsorbed several "model" biomaterial surfaces with proteins and then measured foreign body giant cell (FBGC) formation, tumor necrosis factor alpha (TNFalpha) release, and procoagulant activity. The model surfaces were tissue culture polystyrene (TCPS), untreated polystyrene (PS), and Primaria, whereas the proteins used were albumin, fibronectin, fibrinogen, and immunoglobulin. FBGC formation, TNFalpha release, and procoagulant activity of monocytes were the highest for surfaces preadsorbed with IgG. FBGC formation was lower on surfaces with adsorbed fibrinogen and fibronectin than on uncoated surfaces. TNFalpha release and procoagulant activity of monocytes were similar on surface adsorbed with fibrinogen, fibronectin, or albumin. Monocyte activation was also affected by the surface chemistry of the substrates, because FBGC formation was the highest on PS and the lowest on TCPS. Monocyte procoagulant activity was the highest on Primaria. Adsorbed proteins and surface chemistry were found to have strong effects on FBGC formation, monocyte TNFalpha release, and procoagulant activity in vitro, providing support for the idea that these same variables could affect macrophage-mediated foreign body response to biomaterials in vivo.

The Effect of Interfacility Transfer on Outcome in an Urban Trauma System

BACKGROUND

Transporting all trauma patients to regional trauma centers is inefficient; however, the bypass of nearer, nondesignated hospitals in deference to regional trauma centers decreases mortality in the severely injured. One approach to improving efficiency is to allow the initial assessment of selected patients at lower level (Level III/IV) designated centers. We set out to evaluate whether patients initially assessed at these centers and then transferred to a Level I facility were adversely affected by delays to definitive care.

METHODS

This is a retrospective cohort study in which the primary exposure being evaluated is initial assessment at a Level III or IV trauma center before transport to a Level I center in an urban setting. The outcomes in this transfer cohort were compared with outcomes in patients transported directly from the scene to a Level I center (direct cohort). The outcomes of interest were mortality, length of stay, and hospital charges. Multivariate analyses were used to adjust for differences in baseline characteristics across these two cohorts.

RESULTS

Crude length of stay was comparable, whereas mortality was lower and charges were 40% higher in the transfer cohort (n = 281) compared with the direct cohort (n = 4,439). After adjusting for confounders, mortality and length of stay were similar and total charges were significantly greater in the transferred patients.

CONCLUSION

Interfacility transfers in a mature urban trauma system do not appear to impact on clinical outcome. However, transfer patients use significantly greater resources as measured by hospital charges. This effect is likely because of the nature of their injuries or, alternatively, delays in reaching definitive care.

Induction of heme-oxygenase 1 inhibits endothelial cell activation by endotoxin and oxidant stress

BACKGROUND

Increased oxidant stress has been implicated in a number of disease states, including systemic inflammation caused by ischemia/reperfusion injury or sepsis. We have demonstrated previously that oxidants enhance the proinflammatory response to endotoxin (lipopolysaccharide), although antioxidants inhibit this response. Heme-oxygenase 1 (HO-1) is an inducible, cytoprotective enzyme, which is up-regulated under conditions of oxidant stress. We hypothesized that the induction of HO-1 protein would attenuate the proinflammatory response of endothelial cells to lipopolysaccharide and oxidant stress.

METHODS

Human umbilical vein endothelial cells were pretreated with hemin (100 micromol/L) for 5 hours, and the induction of HO-1 was confirmed by Western blot. After hemin exposure, cells were treated for 1 hour with either diamide, buthione sulfoximine, xanthine oxidase, or glucose oxidase to induce oxidant stress or lipopolysaccharide to induce an inflammatory response. Interleukin 8 (IL-8) and prostaglandin I(2) (PGI(2)) production were measured by enzyme-linked immunosorbent assay; p38 kinase, p42/44 extracellular regulated kinase, and c-jun N terminal kinase activation were measured by Western blot.

RESULTS

HO-1 protein was increased 3-fold by exposure to hemin under all conditions. IL-8 production in response to lipopolysaccharide and xanthine oxidase was inhibited significantly by hemin exposure, although PGI(2) production was not affected. The up-regulation of HO-1 protein levels resulted in the inhibition of the lipopolysaccharide- and oxidant-induced activation of all 3 mitogen-activated protein kinases: p38 kinase, p42/44 extracellular regulated kinase, and c-jun N terminal kinase.

CONCLUSIONS

The induction of HO-1 by hemin results in inhibition of the proinflammatory response of endothelial cells, as evidenced by the inhibition of IL-8 production without affecting PGI(2) production. All 3 mitogen-activated protein kinase signaling cascades are affected, which suggests that the mechanism of this effect may be proximal in the cell signaling process.