Organ injury scaling: spleen and liver (1994 revision).
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Humans↗
Biomedical subjects
E E Moore
Publications and source records attributed to E E Moore.
Trauma systems, trauma centers, and trauma surgeons: opportunity in managed competition.
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General Surgery↗
CD11b blockade prevents lung injury despite neutrophil priming after gut ischemia/reperfusion.
Gut ischemia/reperfusion (I/R) provokes lung injury via a mechanism that involves neutrophils [polymorphonuclear neutrophils (PMNs)]. CD11b/CD18 (alpha mB2) is the integrin receptor on PMNs critical for adhesion-dependent oxidative burst. The purpose of this study was to investigate the mechanistic role of CD11b in the process of gut I/R-induced lung injury. Sprague-Dawley rats underwent 45 minutes of superior mesenteric artery (SMA) occlusion with and without CD11b monoclonal antibody treatment (IB6) (1 mg/kg, i.v.), before SMA clamping. At 2-hour reperfusion, PMN presence in tissue was quantitated by myeloperoxidase activity and circulating PMN priming determined by the difference in superoxide production with and without N-formyl-methionyl-leucyl-phenylalanine, whereas lung leak was assessed by 125I-albumin lung/blood ratio. In sum, CD11b blockade prevented gut I/R-induced lung leak, but did not attenuate gut I/R-induced PMN priming or tissue PMN accumulation. In conclusion, gut I/R promotes PMN priming and PMN adhesion in both local and distant beds via receptors other than CD11b, but this B2 integrin receptor is critical for PMN-mediated endothelial injury.
Animals↗
Interleukin-8 increases endothelial permeability independent of neutrophils.
Interleukin-8 (IL-8) has been associated with a variety of hyperinflammatory states and adverse clinical events. Circulating IL-8 levels correlate with the severity of tissue trauma, and excessive elevations of IL-8 are associated with postinjury adult respiratory distress syndrome and multiple organ failure. While IL-8 is a potent neutrophil (PMN) chemoattractant and activator and enhances PMN transendothelial migration, it also acts to inhibit PMN adhesion to stimulated endothelial cells (ECs). We hypothesized that IL-8 could interact directly with ECs to increase permeability independent of PMNs. Human umbilical vein ECs (HUVECs) were cultured on collagen-coated micropore filters, and integrity of the EC monolayer measured by albumin flux across the filter. Cytochalasin D was used as a positive control. IL-8 induced increased permeability at a concentration of 1000 ng/mL. This effect was abrogated by preincubation of HUVECs with a protein synthesis inhibitor (cycloheximide). These data suggest a role for IL-8 in promoting endothelial leak independent of PMNs, via a mechanism involving protein synthesis.
Cell Membrane Permeability↗
Quantitative sensitivity of ultrasound in detecting free intraperitoneal fluid.
The minimum volume of intraperitoneal fluid that is detectable in Morison's pouch with ultrasound in the trauma setting is not well defined. To evaluate this question, we used diagnostic peritoneal lavage (DPL) as a model for intraperitoneal hemorrhage and undertook a blinded prospective study of the sensitivity of ultrasound in detecting intraperitoneal fluid. Participants included attending physicians and residents in emergency medicine, radiology, and surgery. During the infusion of the DPL fluid, participants continuously scanned Morison's pouch until they detected fluid. All participants were blinded to the rate of infusion and the volume infused. One hundred patients were entered into the study. The mean volume of fluid detected was 619 mL. Only 10% of participants detected fluid volumes less than 400 mL and the overall sensitivity at one liter was 97%. We conclude that reliable detection of intraperitoneal fluid in Morison's pouch requires a greater volume than has been previously described.
Abdominal Injuries↗
Early neutrophil sequestration after injury: a pathogenic mechanism for multiple organ failure.
Polymorphonuclear neutrophils (PMNs) play a pivotal role in the inflammation that precedes multiple organ failure (MOF). In a rat model of MOF, PMNs become primed for enhanced superoxide anion (O2-) release and CD11b expression, sequester in end organs, and produce organ failure. Therefore, we hypothesized that circulating PMNs harvested in the first 24 hours after injury from trauma patients at risk for MOF would (1) exhibit a primed O2- release, (2) upregulate CD11b expression, and (3) show evidence of sequestration in tissues. Extracellular PMN O2- release and CD11b receptor expression were measured at 3, 6, 12, and 24 hours after injury in 33 torso trauma patients with Injury Severity Scores > 15; eight patients (24%) developed MOF. Healthy adults served as controls. PMNs after injury were primed for enhanced in vitro O2- release at 3, 6, 12, and 24 hours after injury, indicating prior in vivo priming. CD11b expression was also increased at 6, 12, and 24 hours after injury. Circulating PMN numbers increased sharply at 3 hours after injury, before decreasing dramatically at 6 and 12 hours, suggesting end organ sequestration. At 12 hours after injury, declines in circulating PMNs were significantly greater in MOF than in non-MOF patients (p < 0.05). These data indicate that PMNs are quickly mobilized into the circulation after injury and then primed for enhanced O2- release and CD11b expression. PMN priming appears to be a necessary preamble to PMN sequestration in patients with major torso trauma. Upregulation of PMN function, accompanied by subsequent end organ sequestration, may represent an important early event in the pathogenesis of MOF after injury.
Adult↗
Inhaled nitric oxide variably improves oxygenation and pulmonary hypertension in patients with acute respiratory distress syndrome.
OBJECTIVE: The purpose of this study was to determine the effect of inhaled nitric oxide (NO) on oxygenation, hemodynamics, and ventilation in patients with adult respiratory distress syndrome (ARDS). METHODS: Sixteen trials of inhaled NO were performed in 14 ARDS patients (age 42.9 +/- 6) who had significant pulmonary hypertension (mean pulmonary artery pressure > 30 mm Hg). Patients were monitored with arterial and pulmonary artery catheters. Volume ventilation was performed by a strict protocol. Data were collected at baseline and 30 minutes after 20 and 40 ppm NO. RESULTS: Overall, the Pao2/FIO2 ratio increased from 69.5 +/- 3.9 to 100.8 +/- 9.5 at 20 ppm, a 42.9 +/- 8.7% increase, and to 97.7 +/- 13.1 at 40 ppm, a 44.1 +/- 14.2% increase over baseline (p = 0.001). However, 5/16 trials demonstrated minimal improvement (Pao2/FIO2 ratio increase < 20%), 5 moderate improvement (20-50%), and 6 marked improvement (> 50%). Overall the mean pulmonary artery pressure (MPAP) decreased from 41.1 +/- 1.8 mm Hg to 34.3 +/- 1.3 at 20 ppm and 33.5 +/- 1.8 mm Hg at 40 ppm, a 15.0 +/- 3.7% decrease, p = 0.002. However, 5/16 trials demonstrated minimal improvement (MPAP decrease < 10%), 7 moderate improvement (10-20%), and 4 marked improvement (> 20%). At 40 ppm NO, 4 patients with moderate improvement in MPAP at 20 ppm NO had marked improvement. There were no changes in systemic oxygen delivery and consumption, intrapulmonary shunt, or lung compliance at 20 or 40 ppm (p > 0.05). Following collection of these data, prolonged NO inhalation (2-20 ppm) was done in 10 of 14 patients for 4.5 +/- 0.7 days (range 1-10 days). Overall, there were 7 deaths (mortality 50%). In patients receiving prolonged NO, there were 3 deaths (mortality 30%). All 4 patients who failed to respond to inhaled NO subsequently died (mortality 100%). CONCLUSIONS: Inhaled NO improves oxygenation and pulmonary hemodynamics in patients with ARDS. However, the improvement to NO is variable.
Adolescent↗
Organ injury scaling. VI: Extrahepatic biliary, esophagus, stomach, vulva, vagina, uterus (nonpregnant), uterus (pregnant), fallopian tube, and ovary.
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Biliary Tract↗
Postinjury neutrophil priming and activation states: therapeutic challenges.
Both hyperactivity and hypoactivity of neutrophils (PMNs) have been implicated in the pathogenesis of postinjury multiple organ failure. In this paper, the cellular and molecular mechanisms involved in the regulation of PMN O2- production are reviewed. In addition, relevant research laboratory techniques for measuring both intracellular and extracellular O2- release are outlined. In a pilot study PMN O2- release in response to a battery of PMN agonists was determined, and four functional states of the NADPH were defined: resting, primed, activated, and unresponsive. PMNs from normal adult volunteers are in the resting state. In contrast, PMNs from patients with severe torso trauma are primed and activated in the first 24 h postinjury, but, after 48 h, become unresponsive to both receptor-dependent (platelet activating factor and N-formyl-methyl-leucyl-phenylalanine) and receptor-independent (phorbol 12-myristate 13-acetate) activation. The ability to identify at-risk patients and provide a rationale for ameliorating PMN-mediated tissue injury in patients with hyperinflammation syndromes are discussed. In addition, the importance of identifying patients with PMNs that are unresponsive, and the necessity for increasing PMN function in these patients in order to reduce the risk of sepsis, are also discussed.
Humans↗
Gut phospholipase A2 mediates neutrophil priming and lung injury after mesenteric ischemia-reperfusion.
Intestinal ischemia-reperfusion (I/R) provokes polymorphonuclear neutrophil (PMN)-mediated lung injury via a process characterized by circulating PMN priming, pulmonary PMN sequestration, and increased microvascular leak in the lung. We found in rats subjected to intestinal I/R (ischemia 45 min and reperfusion 6 h) that 1) intestinal phospholipase A2 (PLA2) was activated during ischemia, 2) circulating PMN priming (assessed by superoxide production with N-formyl-Met-Leu-Phe) occurred after 1 h reperfusion, and 3) exaggerated 125I-labeled albumin lung leak occurred after 2 h reperfusion, compared with sham-treated animals (P < 0.05). Treatment with a PLA2 inhibitor, quinacrine, within 15 min of reperfusion reversed the exaggerated gut PLA2 activity and abrogated subsequent PMN priming and lung leak (P < 0.05). However, when quinacrine was administered after 2 h of reperfusion, circulating PMN priming and lung leak continued to evolve despite suppression of intestinal PLA2 activity. We conclude that intestinal PLA2 activation may be a prerequisite for the sequelae of circulating PMN priming and pulmonary microvascular leak observed after intestinal I/R.
Animals↗
Quantifying oxidative injury in the liver.
Oxidative injury is a mechanism common to both ischemia-reperfusion (IR) and leukocyte-mediated injury. Reperfused tissue beds and elaborated mediators can activate a cascade of intercellular and interorgan injuries that often precipitates multiple organ failure. Initiation of lung injury by gut IR is a case in point, but concomitant liver injury may have been overlooked because of the absence of comparably sensitive physiological markers. In this study, we explore the hypothesis that occurrence of portally derived oxidant-induced liver dysfunction may be detected with both sensitivity and specificity. We simulated pure oxidative injury to the liver and separated the contributions from secondary systemic oxidation. Both tissue and plasma indicators were evaluated, each reflecting aspects of oxidation, membrane integrity, and metabolic function. Tissue markers readily detect oxidative liver injury, but systemic 3-hydroxybutyrate (3-OHB) concentration and ketone body ratio (KBR) are the most sensitive. Comparison of 3-OHB concentrations against the corresponding KBR can be used to distinguish adjustments within a physiological range from the transition into injury.
3-Hydroxybutyric Acid↗
von Willebrand factor antigen levels are not predictive for the adult respiratory distress syndrome.
In patients with nonpulmonary sepsis, von Willebrand factor antigen (vWF:Ag or Factor VIIR:Ag) levels have been reported to be predictive for the development of the adult respiratory distress syndrome (ARDS). We addressed the ability to generalize these results by measuring serial Factor vWF:Ag levels in 96 patients at risk for the development of ARDS. Patients with sepsis, pancreatitis, hypertransfusion, witnessed aspiration of gastric contents, abdominal trauma, chest trauma, and multiple fractures were studied. Sequential measurements were obtained at enrollment into the study (T = 0), and T = 6, 12, 24, and 48 h. Subjects were grouped into sepsis and nonsepsis categories and analyzed according to the following outcome definitions: ARDS and non-ARDS. The mean values for the sepsis and nonsepsis groups were elevated above normal at all time points. A statistically significant difference occurred in the mean vWF:Ag level for the ARDS and non-ARDS patients in the nonsepsis group at T = 0 (p = 0.05). To assess the clinical utility of these results, ROC (receiver operating characteristics) curves were plotted at T = 0, and optimal cutoff values of vWF:Ag were determined. In the sepsis group, the best value for vWF:Ag above which patients would actually develop ARDS was 399%, resulting in a 70% sensitivity and a 47% specificity. For the non-sepsis patients, the optimal value was 273%, yielding a sensitivity of 64% and a specificity of 52%. We conclude that measuring vWF:Ag levels are not helpful in predicting the progression to ARDS in multiple at-risk patients.
Adult↗
Neutrophil response to endotoxin in the adult respiratory distress syndrome: role of CD14.
The role of both endotoxin and neutrophils in the development of acute lung injury continues to be debated. We hypothesized that early in the course of the development of the adult respiratory distress syndrome (ARDS) circulating neutrophils could be primed by endotoxin and that subsequent stimulated responses could be enhanced. Accordingly, neutrophils were isolated from patients at risk for and with ARDS. Unstimulated neutrophils from these patients neither produced nor were primed for superoxide production. Whereas phorbol myristate acetate-stimulated superoxide production was preserved, indicating that the cells were capable of a response, patient neutrophils produced less superoxide than did cells from normal subjects when primed with endotoxin (lipopolysaccharide [LPS]) and stimulated with formyl-methionyl-leucine-phenylalanine (FMLP), suggesting that there was a defect in the signal transduction mechanism for LPS. This was confirmed by the finding that patient neutrophils also had both decreased baseline CD14 expression and less CD14 upregulation after LPS stimulation compared with neutrophils from normal subjects. The mechanisms that could account for the decreased CD14 expression were studied in vitro. Neutrophils from normal subjects both upregulate CD14 in response to LPS and shed CD14 over time, suggesting that in patients CD14 receptors could have been previously upregulated and shed. In addition, there is an association between CD14 expression and retention such that normal LPS-stimulated neutrophils which are not retained in a filtration system have decreased CD14 expression. Thus, in patients, those PMN most responsive to LPS could be preferentially sequestered and not available in the circulation for study.
Adult↗
Functionally different isoforms of the human calcitonin receptor result from alternative splicing of the gene transcript.
Two subtypes of the human calcitonin receptor (hCTR) have been described which differ from one another by the presence or absence of a 16-amino acid insert in the first intracellular loop. Both isoforms were stably expressed in baby hamster kidney cells to compare their ligand binding and second messenger coupling. The binding affinity and the on/off rate of binding for salmon CT were identical for the two receptor isoforms. However, the presence of the insert significantly reduced the ability of the receptor to couple to both adenylate cyclase and phospholipase C. Stimulation of a transient calcium response was only observed with the insert-negative receptor. Similarly, the ED50 for the cAMP response is 100-fold higher for the insert-positive form compared with the insert-negative form of the receptor. However, the maximal cAMP response was equivalent for both receptor isoforms. The rate of internalization of the insert-positive form of the receptor is significantly impaired relative to the insert-negative receptor, which suggests that this process may be dependent on the stimulation of a second messenger pathway. Cloning and characterization of the relevant portion of the hCTR gene revealed that these isoforms are generated by alternative splicing. We also discovered a third isoform of the hCTR, which can be generated by alternative splicing at the same position. The presence of a stop codon in this newly described alternative exon would lead to premature termination of the receptor at the C-terminal end of the first transmembrane domain.
Alternative Splicing↗
Comparative cognitive effects of phenobarbital, phenytoin, and valproate in healthy adults.
The relative effects of antiepileptic drugs (AEDs) on cognition are controversial. We compared the cognitive effects of phenobarbital, phenytoin, and valproate in 59 healthy adults using a randomized, double-blind, incomplete-block, crossover design. Cognitive assessments were conducted at baseline, after 1 month on each drug (two AEDs per subject), and at two repeat baselines 11 weeks after each AED treatment. The neuropsychological battery included 12 tests, yielding 22 variables: Choice Reaction Time, P3 Event-Related Potential, Finger Tapping, Lafayette Grooved Pegboard, Selective Reminding Test, Paragraph Memory, Complex Figures, Symbol Digit Modalities Test, Stroop Test, Visual Serial Addition Test, Hopkins Symptom Checklist, and Profile of Mood States. More than one-half of the variables exhibited AED effects when compared with nondrug baselines, and all three AEDs produced some untoward effects. Differential AED effects on cognition were present for approximately one-third of the variables. Phenobarbital produced the worst performance; there was no clinically significant difference between phenytoin and valproate.
Adult↗
Clinical benefits of early post-injury enteral feeding.
Over the past two decades, clinical studies have provided convincing evidence that early nutritional support benefits metabolically stressed surgical patients by preventing acute protein malnutrition. However, the optimal route of substrate delivery (ie, enteral versus parenteral) continues to be debated. Recent basic and clinical investigation offers the exciting possibility that the beneficial effects of traditional nutritional support can be amplified by supplementing specific nutrients that exert pharmacological immune-enhancing effects. Over the past 15 years, the Department of Surgery at the Denver General Hospital has focused clinical research efforts on defining optimal nutrition following major torso trauma. The purpose of this paper is to review our studies as well as other clinical studies in order to answer three questions: 1) Does early post-injury nutritional support improve patient outcome? 2) What is the preferred route of substrate delivery? 3) Do new 'immune-enhancing' diets offer additional clinical benefits?
Enteral Nutrition↗
Laparoscopic appendicectomy: a trainee's perspective.
Minimally invasive surgery is rapidly becoming an integral part of general surgery. Many general surgeons have been trained to undertake laparoscopic cholecystectomy. It has been recommended that laparoscopic appendicectomy should be the training operation for junior surgeons. The aim of our study was to assess whether laparoscopic appendicectomy training can safely be introduced to junior surgeons in a district general hospital. During the 11 month study period, 27 laparoscopic and 38 open appendicectomies were performed. The median anaesthetic time was 80 min for laparoscopic and 52.5 min for open appendicectomies. Laparoscopic appendicectomies cost, on average, 618 pounds and open appendicectomies 770 pounds per case. The complication rate between the two procedures was equal. We therefore showed that laparoscopic appendicectomy by junior surgeons is both safe and cost-effective. Although the registrar did most of the laparoscopic appendicectomies, with resultant less operating for the SHO, laparoscopic appendicectomy provided the SHO with training in diagnostic laparoscopy and laparoscopic dissection. We conclude that basic laparoscopic training should be introduced early in surgical training, after which laparoscopic appendicectomy is a safe procedure for surgical trainees.
Adolescent↗
Divergent structural requirements exist for calcitonin receptor binding specificity and adenylate cyclase activation.
The basis of the high potency of salmon calcitonin (sCT) in radioligand binding competition and cAMP accumulation studies with cloned calcitonin (CT) receptors from rats, pigs, and humans was examined using two sets of CT analogues, i.e., chimeric sCT/human CT (hCT) analogues and analogues of sCT with differing capacities to form an amphipathic alpha-helix. In competition for 125I-sCT binding the following relative specificities were observed for the chimeric peptides: rat C1a CT receptor, sCT > or = (1-16)hCT/(17-32)sCT (ACT-15) > (1-16)sCT/(17-32)hCT (ACT-27); rat C1b CT receptor, sCT >> ACT-15 > ACT-27; hCT receptor, sCT = ACT-15 > ACT-27; porcine CT receptor, sCT > ACT-27 > ACT-15. In contrast, in ligand-induced cAMP accumulation studies the relative efficacies were as follows: rat C1a CT receptor, sCT = ACT-15 > ACT-27; rat C1b CT receptor, sCT = ACT-15 > ACT-27; hCT receptor, sCT = ACT-15 > or = to ACT-27; porcine CT receptor, sCT = ACT-15 = ACT-27. The data demonstrate that residues present in the carboxyl-terminal half of sCT are more important for binding competition with the rat C1a, rat C1b, and human CT receptors, whereas residues in the amino-terminal half of sCT are more important for binding competition with the porcine CT receptor. Carboxyl-terminal sCT residues are also important for full potency in adenylate cyclase activation with the rat C1a and rat C1b CT receptors but are less important for activation via the hCT receptor. The disparity in the relative potencies of the peptides in studies of binding competition and cAMP accumulation is suggestive of significant differences in the relative affinities of the peptides for active and inactive conformations of the CT receptor. The use of sCT analogues with varying capacities to form alpha-helices also revealed divergence in the responses of different receptors. This was most apparent for the stimulation of cAMP production by the rat receptor isoforms C1a and C1b. In cells expressing the C1a receptor, the helical analogues sCT and des-Ser2-sCT were equipotent with [Gly8]-des-Leu19-sCT and des-1-amino-[Ala1,7,Gly8]-des-Leu19 sCT, analogues that have reduced or absent helical structure, respectively. In contrast, the nonhelical analogues were 100-1000-fold less potent than sCT and des-Ser2-sCT at the C1b receptor. In general, reduction in the ability of sCT analogues to form helix structures had a greater impact on the potency of the analogues in competition for 125I-sCT binding than in cAMP accumulation.(ABSTRACT TRUNCATED AT 400 WORDS)
Adenylyl Cyclases↗