Neutrophils from burn patients are unable to increase the expression of CD11b/CD18 in response to inflammatory stimuli.

Neutrophils (PMNs) from patients with thermal injury are dysfunctional for the CD11b/CD18-dependent functions of diapedesis, chemotaxis, and phagocytosis. The expression of CD11b/CD18 on normal PMNs is increased after an inflammatory stimulus. We proposed that CD11b/CD18 expression on burn patient PMNs would respond abnormally to inflammatory stimuli. PMNs were obtained from nonseptic burn patients during the second week after thermal injury. PMNs from burn patients incubated with lipopolysaccharide (LPS), N-formyl-methionyl-leucyl-phenylalanine, phorbol myristate acetate, or A23187 did not increase the expression of CD11b/CD18 to the same degree exhibited by normal PMNs. This inability to increase CD11b/CD18 was not due to differences in CD14 receptor expression, LPS binding, or factors present in the serum of burn patients. The upregulation of CD35 also was decreased on burn patient PMNs. Western blot analysis revealed decreased quantities of CD11b protein in burn patient PMNs compared with normal control PMNs. The deficiency in CD11b/CD18 expression after inflammatory stimuli may explain some of the abnormalities observed in burn PMN function.

Nitric oxide: an overview.

Nitric oxide (NO), a paracrine-acting gas enzymatically synthesized from L-arginine, is a unique biologic mediator that has been implicated in a myriad of physiologic and pathophysiologic states. It is an important regulator of vascular tone and may be the mediator of the hemodynamic changes involved in sepsis and cirrhosis. In addition, there is increasing evidence that NO is involved in coagulation, immune function, inhibitory innervation of the gastrointestinal tract, protection of gastrointestinal mucosa, and the hepatotoxicity of cirrhosis. It has already been speculated that NO may represent a point of control or intervention in a number of disease states. The purpose of this paper is to provide the surgeon with a broad overview of the scientific and clinical aspects of this important molecule.

The accuracy of gastric insufflation in testing for gastroesophageal perforations during laparoscopic Nissen fundoplication.

BACKGROUND: Laparoscopic Nissen fundoplication is an effective technique for the symptomatic relief of the manifestations of gastroesophageal reflux disorder but is associated with a 0.8-1% rate of gastroesophageal perforation. Early detection and repair of these injuries is critical to patient outcome, but occult injuries occur and may be missed. Gastric insufflation technique evaluates the integrity of the gastroesophageal wall after laparoscopic Nissen fundoplication. Gastric insufflation technique involves occlusion of the proximal stomach with a noncrushing bowel clamp while insufflating the submerged gastroesophageal junction. We conducted an animal study to assess the utility of gastric insufflation technique. METHODS: Five pigs (mean weight, 40.4 kg) underwent testing of laparoscopic gastric insufflation technique. In four animals, laparoscopic Nissen fundoplication was performed and then gastroesophageal junction injuries were created (3-5 mm distraction-type wall injuries). Non-crushing bowel clamps provided occlusion of the pylorus and then the proximal stomach during gastroesophageal insufflation. The gastroesophageal junction was then submerged. In the fifth animal, gastric insufflation technique was repeated while calibrated injuries were created to determine the smallest detectable injury. An injury was considered detectable if rising air bubbles were noted from the submerged gastroesophageal structures. Maximal luminal pressures needed to detect injuries were recorded with an in-line manometer. RESULTS: In all animals, 5-7 mm injuries of the gastroesophageal junction were easily detected using gastric insufflation technique when the proximal stomach was occluded. When the pylorus alone was occluded, detection of gastroesophageal injuries was inconsistent. Small injuries (<3 mm) of the esophagus were difficult to visualize with pyloric occlusion alone but were consistently detectable with proximal stomach occlusion at pressures less than 20 mm Hg. When the pylorus alone was occluded, the smallest detectable stomach perforation was a 16-gauge needle puncture while applying maximal gastric pressure (40-60 mm Hg) and a 2.5 mm linear injury when generating lower pressures (20 mm Hg). CONCLUSION: Proximal stomach occlusion and insufflation appears to effectively detect esophageal injuries of likely clinical importance (>2.5 mm). Pyloric occlusion and insufflation reliably evaluates the anterior stomach for injury. Gastric insufflation technique is a useful method for detecting gastroesophageal injury after laparoscopic Nissen fundoplication.

Alterations of neutrophil responses to tumor necrosis factor alpha and interleukin-8 following human endotoxemia.

Interleukin-8 (IL-8), a neutrophil chemoattractant and activating cytokine, has been implicated as a proinflammatory mediator in gram-negative sepsis. In vitro data support the notion of IL-8 as an endothelial adherence inhibitor. To evaluate this issue, we infused six volunteers with reference endotoxin and measured plasma levels of IL-8, neutrophil tumor necrosis factor alpha (TNF-alpha) receptors, TNF-alpha-induced adherence to fibronectin, and neutrophil chemotaxis to IL-8 and other attractants. We found that, at 3 h postinfusion, IL-8 but not TNF-alpha plasma levels were elevated. Neutrophils had shed L-selectin (mean channel fluorescence decrease, 79 +/- 9 to 49 +/- 7; P = 0.0625) and TNF-alpha receptors (decrease in number of receptors per cell, 1,596 +/- 340 to 574 +/- 93; P = 0.004). Cells were chemotactically desensitized to IL-8. TNF-alpha-induced adherence to fibronectin was suppressed from 69% +/- 5% of the phorbol myristate acetate response to 38% +/- 7% (P = 0.0154). These findings support the notion that release of IL-8 into the vascular space may be an in vivo mechanism for suppression of neutrophil accumulation at extravascular sites. L-Selectin loss would reduce the ability of neutrophils to adhere to activated endothelial cells. The specific loss of migratory response to IL-8 would impair neutrophil delivery to areas where IL-8 was the predominant chemoattractant. Loss of TNF-alpha-induced adherence to fibronectin would blunt those responses, including production of oxidants, capacitated by adherence.

Analysis of cloned structural and regulatory genes for carbohydrate utilization in Pseudomonas aeruginosa PAO.

Five of the genes required for phosphorylative catabolism of glucose in Pseudomonas aeruginosa were ordered on two different chromosomal fragments. Analysis of a previously isolated 6.0-kb EcoRI fragment containing three structural genes showed that the genes were present on a 4.6-kb fragment in the order glucose-binding protein (gltB)-glucokinase (glk)-6-phosphogluconate dehydratase (edd). Two genes, glucose-6-phosphate dehydrogenase (zwf) and 2-keto-3-deoxy-6-phosphogluconate aldolase (eda), shown by transductional analysis to be linked to gltB and edd, were cloned on a separate 11-kb BamHI chromosomal DNA fragment and then subcloned and ordered on a 7-kb fragment. The 6.0-kb EcoRI fragment had been shown to complement a regulatory mutation, hexR, which caused noninducibility of four glucose catabolic enzymes. In this study, hexR was mapped coincident with edd. A second regulatory function, hexC, was cloned within a 0.6-kb fragment contiguous to the edd gene but containing none of the structural genes. The phenotypic effect of the hexC locus, when present on a multicopy plasmid, was elevated expression of glucokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydratase, and 2-keto-3-deoxy-6-phosphogluconate aldolase activities in the absence of inducer.