摘要:

BackgroundIn response to isolated inflammatory stimuli, changes in endothelial cell morphology that enhance paracellular flow of solutes result from F-actin stress fiber formation, myosin phosphorylation, and actin anchoring protein (ZO-1) modifications. We hypothesized that myosin light chain kinase inhibition would diminish burn-enhanced endothelial monolayer permeability by secondarily preventing F-actin and actin anchoring protein rearrangements.MethodsHuman pulmonary microvascular endothelial cells were treated for 4 hours with 20% human burn serum (isolated from patients with > 45% total body surface area thermal injury or healthy volunteers). Select cultures were pretreated with myosin light chain kinase inhibitors (ML-9). Permeability was assessed by migration of bovine serum albumin across cell monolayers. Cells were stained with rhodamine-phalloidin and anti–ZO-1 antisera and examined by means of confocal microscopy.ResultsBurn serum significantly enhanced monolayer permeability to albumin, whereas pretreatment with ML-9 limited this effect. Control cells maintained cortical F-actin and peripheral ZO-1 distributions (1a, b), whereas burn serum induced transcellular F-actin stress fiber formation and a diffuse ZO-1 staining (2a, b). ML-9 prevented burn-induced actin rearrangements, but not the diffuse redistribution of ZO-1.ConclusionThese data demonstrate that endothelial F-actin stress fiber formation and ZO-1 redistribution contribute to postburn loss of pulmonary endothelial monolayer integrity. Although myosin phosphorylation appears to be required for endothelial F-actin stress fiber formation, redistribution of actin-membrane anchoring proteins appears to be regulated independently after thermal injury.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundProinflammatory eicosanoids formed from arachidonic acid (AA) by lipoxygenase (LO) and cyclooxygenase (COX) pathways have been shown to inhibit apoptosis in certain cell types. This study determined whether inhibition of LO and COX increased apoptosis in AA-treated HL-60 cells in vitro.MethodsHL-60 cells were incubated with 50 &mgr;mol/L AA and an enzyme inhibitor (1–10 &mgr;mol/L) for COX, LO, 12-LO, and 5-LO for 12 hours. Flow cytometry was used to assess viability, apoptosis, and necrosis. Apoptosis was further assessed using terminal dUTP nick end-labeling and DNA fragmentation.ResultsThe highest concentration of LO inhibitors, but not COX inhibitors, decreased viability and increased apoptosis and necrosis in the presence of exogenous AA.ConclusionThese results suggest that disruption of the metabolism of AA by LO, in particular 5-LO, decreases cell survival and increases apoptosis. Thus, downstream metabolic processing of AA by LO but not COX plays a critical role in the regulation of HL-60 cell apoptosis.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundEndotoxin not only activates the Toll-mediated signaling pathway within endothelial cells that leads to neutrophil migration but also causes the polymerization of microtubules. The potential role of this polymerization event, however, is unknown.MethodsHuman umbilical vein endothelial cells stimulated with endotoxin were pretreated with or without the microtubule depolymerizing agent colchicine. Toll-mediated signaling events and protein production were in turn investigated by Western blot, gel shift, and enzyme-linked immunosorbent assay. Finally, neutrophil adhesion was assayed fluorometrically under the various conditions.ResultsEndotoxin led to activation of the various Toll-mediated pathways, production of intercellular adhesion molecule-1 and interleukin-8, and subsequent neutrophil adhesion. Pretreatment with colchicine led to selective inhibition of anti-dual phosphorylated extracellular signal-regulated kinase-1/2, anti-dual phosphorylated c-jun N-terminal kinase, and adaptor protein-1; selective enhancement of p38; and no effect on nuclear factor-&kgr;B. This selective modulation of intracellular signaling resulted in attenuated intercellular adhesion molecule-1, interleukin-8 and prostaglandin E2production, but enhanced cyclooxygenase-2 expression. As a result, microtubule disruption led to a significant reduction in neutrophil adhesion.ConclusionMicrotubule formation is essential to optimal endotoxin-induced intracellular signaling through anti-dual phosphorylated extracellular signal-regulated kinase-1/2, anti-dual phosphorylated c-jun N-terminal kinase, and adaptor protein-1. Failure of these signaling events is associated with a marked reduction in the formation of a proadhesive phenotype that may prove to be beneficial in modulating neutrophil recruitment during sepsis.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundPolymorphonuclear leukocyte (PMNL)-derived microparticles (MPs) have been recently reported as activators of vascular endothelium in vitro. The objectives of the present study were to evaluate the production of MPs in severely injured patients and to clarify the role of these MPs.MethodsThirty severely injured patients (mean Injury Severity Score of 27 ± 11) and 21 healthy volunteers participated in the study. Blood samples were obtained serially at three time points: days 0 to 1, days 2 to 5, and days 6 to 12 after the trauma event. MP production, CD11b and CD62L expression on MPs, and oxidative activity in PMNLs were measured by flow cytometry in both the presence and absence of formylmethionyl-leucyl-phenylalanine. Expressions of CD11b and CD62L were differentially evaluated according to the size of the MPs (≥ or < 1.0 &mgr;m). Soluble E-selectin and thrombomodulin levels in blood, variables representative of systemic vascular endothelial damage, were also measured.ResultsProduction of MPs with and without formylmethionyl-leucyl-phenylalanine and the oxidative activity in PMNLs (O2−) were prominently increased on days 2 to 5 after trauma. CD62L expression was enhanced on MPs at all three time points, and CD11b expression was enhanced on MPs < 1.0 &mgr;m in diameter at all three time points. Soluble E-selectin and thrombomodulin in blood did not change significantly between time points.ConclusionActivated PMNLs enhance production of PMNL-derived MPs with increased adhesion molecule expression on days 2 to 5 after severe trauma. This response per se, however, may not progress to systemic vascular endothelial damage.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundHypertonic saline (HTS) attenuates polymorphonuclear neutrophil (PMN)-mediated tissue injury after hemorrhagic shock. We hypothesized that HTS resuscitation reduces early in vivo endothelial cell (EC)-PMN interactions and late lung PMN sequestration in a two-hit model of hemorrhagic shock followed by mimicked infection.MethodsThirty-two mice were hemorrhaged (40 mm Hg) for 60 minutes and then given intratracheal lipopolysaccharide (10 &mgr;g) 1 hour after resuscitation with shed blood and either HTS (4 mL/kg 7.5% NaCl) or Ringer’s lactate (RL) (twice shed blood volume). Eleven controls were not manipulated. Cremaster intravital microscopy quantified 5-hour EC-PMN adherence, myeloperoxidase assay assessed lung PMN content (2 1/2 and 24 hours), and lung histology determined 24-hour PMN transmigration.ResultsCompared with RL, HTS animals displayed 55% less 5-hour EC-PMN adherence (p= 0.01), 61% lower 24-hour lung myeloperoxidase (p= 0.007), and 57% lower mean 24-hour lung histologic score (p= 0.027).ConclusionCompared with RL, HTS resuscitation attenuates early EC-PMN adhesion and late lung PMN accumulation in hemorrhagic shock followed by inflammation. HTS resuscitation may attenuate PMN-mediated organ damage.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundTransfusion of stored packed red blood cells (PRBCs) has unintended effects beyond the desired results of increased oxygen delivery. A particular concern is the potential for lipid and cytokine mediators present in PRBCs to augment the postinjury inflammatory response that sometimes culminates in multiple organ failure. Through the use of a polymerized human hemoglobin (PolyHeme), we have been able to measure the inflammatory response in patients resuscitated with minimal exposure to banked components in the early postinjury period.MethodsCritically injured patients requiring urgent transfusion were resuscitated with either PRBCs or PolyHeme in the early postinjury period. Proinflammatory cytokines (interleukin [IL]-8 and IL-6), counterregulatory cytokines (IL-10 and IL-11), and markers of endothelial injury (soluble intercellular adhesion molecule and soluble E-selectin) were serially measured.ResultsIncreases in IL-8, IL-6, and IL-10 were greater in patients resuscitated with PRBCs. IL-11 plasma levels were largely below the level of detection of the assay. There was no difference in markers of endothelial injury.ConclusionConsistent with concerns about the immunoinflammatory response to transfusion of PRBCs, we observed exaggerated levels of three markers associated with adverse outcome. The clinical significance of these findings with respect to the development of multiple organ failure awaits further study.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundThe presence of intracellular organisms (ICOs) in polymorphonuclear cells obtained from respiratory secretions is a possible method for rapid diagnosis of ventilator-associated pneumonia. We correlated ICOs with quantitative endotracheal aspirate (QA) in intubated patients.MethodsConsecutive intubated patients in the surgical intensive care unit had respiratory samples obtained every 2 days until extubation. Two thresholds for ICOs and quantitative culture were examined. Sensitivity, specificity, and positive and negative predictive values were calculated using QA as reference.ResultsOne hundred one samples were obtained from 35 patients. Colony counts ≥ 100,000 were found in 34 samples; 60 samples had colony counts ≥ 10,000. Antibiotic use did not affect the sensitivity or specificity of ICOs. Sensitivity of ICOs was 39% to 85%, and specificity was 82% to 97%. Positive predictive value was 70% to 96%, and negative predictive value was 50% to 91%.ConclusionICOs provide a quick method for establishing the presence of a significant bacterial load in the respiratory tract. Accuracy of ICOs in predicting a positive QA is not affected by concurrent antibiotics.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundWe describe the surgical response of two affiliated hospitals during the day of, and week following, the September 11th, 2001 terrorist attack at the World Trade Center in New York City. The city of New York has 18 state designated regional trauma centers that receive major trauma victims. The southern half of Manhattan is served by a burn center, two regional trauma centers, and a community hospital that is an affiliate of one of the regional trauma centers. This report accounts for the surgical response by a regional trauma center (Hospital A, located 2.5 miles from the World Trade Center) and its affiliate hospital (Hospital B, located 5 city blocks from the World Trade Center) on September 11th when two commercial jets crashed into the Twin Towers at the World Trade Center mall.MethodsHospital A maintained a concurrent log of patients received during the first 5 hours, the first day, and the first week after the disaster which was kept by the Surgical Triage Officer. The trauma registry completed and verified this data by September 18th. Hospital B collected its data by hand counting and verification by chart review. Both hospitals, A and B, had established disaster plans that were implemented.ResultsNine hundred eleven patients were received by two affiliated hospitals from the World Trade Center attack. Seven hundred seventy six patients (85%) were walking wounded, sustaining mild inhalation and eye irritant injuries. One hundred thirty five (15%) were admitted with 18 (13%) of these undergoing surgery. Twenty two of the 23 transfers were from the community hospital to specialized orthopedic or burn centers. Of the 109 patients admitted to Hospital A, 30 were to the surgical service. The mean ISS score of these patients was 12. There were 4 deaths (within minutes of arrival at the hospital) and 6 delayed deaths (day 1-14). Excluding walking wounded and DOAs, the critical mortality rate was 37.5% overall.ConclusionThe September 11th, 2001, terrorist attack in New York City, involving two commercial airliners crashing into the World Trade Center, led to 911 patients received at two affiliated hospitals in lower Manhattan. One hospital is a regional trauma center and one was an affiliate community hospital. Eighty five percent of the patients received were walking wounded. Of the rest, 13% underwent surgical procedures with an overall critical mortality rate of 37.5%.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundThe management of trauma patients has become increasingly nonoperative, especially for solid abdominal organ injuries. However, the Residency Review Committee (RRC) still requires an operative trauma experience deemed essential for graduating general surgical residents. The purpose of this study was to review the trauma volume and mix of patients at two trauma centers and determine the major operative trauma cases available to residents involved in the care of these patients.MethodsA retrospective chart review was conducted at the two trauma centers used by the Michigan State University surgery residency. Both of the trauma centers are American College of Surgeons verified. Surgical residents are involved with the care of every trauma patient at each of the hospitals. Cumulative data were collected and analyzed from January 1, 1997, through December 31, 1999. Age, gender, mechanism of injury (blunt vs. penetrating), Injury Severity Score, length of stay, operative interventions, and patients managed nonoperatively were reviewed.ResultsThere were 434 patients selected for this study from 2,340 patients admitted to the trauma services. Male patients accounted for 66% of patients and female patients accounted for 34% of patients. Blunt trauma was the mechanism in 89% of patients, with penetrating trauma accounting for the other 11% of patients. Of the total number of patients, motor vehicle crashes accounted for the majority of cases, 325 of 434 (75%). Overall, 85% (370 of 434) of patients were managed without an index trauma surgical procedure according to RRC guidelines. Only 14.7% (64 of 434) of patients underwent operative intervention that qualified as index trauma surgical cases identified by the RRC. The spleen and small bowel were the two most commonly injured organs found at laparotomy. Nonoperative intervention of many patients with solid abdominal organ injuries did not meet the operation requirements expected by the RRC.ConclusionOur residency program had 10 graduating chief residents over the 3-year time period. With only 64 operative trauma cases, this yields an average of 6.4 trauma cases per resident. This falls significantly short of the 16-case minimum requirement in trauma surgery established by the RRC. The operative trauma requirements established by the RRC for graduating residents may be unattainable in many residency programs because of the high incidence of blunt trauma and the changing patterns of trauma management.

ISSN:0022-5282    

出版商:OVID    

年代:2003

数据来源: OVID