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PubMed1998

Beta2-microglobulin and low-flux synthetic dialyzers.

The aim of this study was to compare the effect on beta2-microglobulin (beta2-M) plasma levels of dialyzers with 3 low-flux synthetic membranes and regenerated cellulose (Cuprophan) in 12 chronic dialysis patients. The synthetic membrane materials chosen were low-flux polymethylmethacrylate (PMMA), low-flux polysulfone (PS 400), and polycarbonate-polyether (Gambrane). Adequate and comparable removal of small solutes was provided by dialyzers with all 4 membrane materials used under similar conditions. A significant reduction of beta2-M plasma levels was seen only with Gambrane while the other 2 synthetic membrane materials gave rise to increases similar to those known to occur with Cuprophan. After correction for the hemoconcentration caused by ultrafiltration, dialysis with Gambrane showed a 24% lower plasma beta2-M level while the beta2-M concentrations with the other 3 membrane materials were practically unchanged. In addition, the efficiency of Gambrane dialyzers in beta2-M removal was able to significantly lower the predialysis plasma beta2-M levels after only 5 dialysis sessions. The hemocompatibility of the 3 synthetic low-flux membranes as judged by the white blood cell (WBC) count and complement activation was similar and therefore cannot be used to explain the different beta2-M plasma levels. In anticipation of gaining further insight into the mechanisms of accumulation and deposition of beta2-M in dialysis patients, a worthwhile approach may be to use a low-flux membrane such as Gambrane which combines removal with protection against potential activating factors in the dialysis fluid.

Aged↗
PubMed2000

Pressure drop, shear stress, and activation of leukocytes during cardiopulmonary bypass: a comparison between hollow fiber and flat sheet membrane oxygenators.

The membrane oxygenator is known to be superior to the bubble oxygenator, but little information is available about the difference between the hollow fiber and flat sheet membrane oxygenators with regard to pressure drop, shear stress, and leukocyte activation. In this study, we compared these 2 types of membrane oxygenators in patients undergoing cardiopulmonary bypass (CPB) surgery with special focus on leukocyte activation and pressure drop across the oxygenators. Plasma concentration of elastase, a marker indicating leukocyte activation, increased to 593+/-68% in the flat sheet oxygenator group versus 197+/-42% in the hollow fiber oxygenator group (p<0.01) at the end of CPB compared to their respective baseline concentrations before CPB. Pressure drop across the oxygenator was significantly higher in the flat sheet group than in the hollow fiber group throughout the entire period of CPB (p<0.01). High pressure drop across the oxygenator as well as the calculated shear stress was positively correlated with the release of elastase at the end of CPB (r = 0.760, p<0.01, r = 0.692, p<0.01). However, this positive correlation existed in the flat sheet oxygenator but not in the hollow fiber oxygenator. Clinically, both membrane oxygenators have satisfactory performance in O2 and CO2 transfer. These results suggest that a higher pressure drop across the flat sheet oxygenator is associated with more pronounced activation of leukocytes in patients undergoing cardiopulmonary bypass.

Adult↗
PubMedDate not supplied

Preparation of white cell-depleted red cells for 42-day storage using an integral in-line filter.

A new blood pack system for the preparation of white cell-depleted red cells was studied. The system is a modified additive-solution quadruple-unit blood pack that incorporates a cellulose-acetate fiber depth filter in-line between the AS-3 additive bag and the CP2D collection bag. Mean +/- SD white cell removal from 156 units processed under standard production conditions was 97.7 +/- 2.7 percent; residual white cells were 1.1 +/- 1.0 x 10(8) per unit. Red cell loss was 10.0 +/- 1.0 percent (n = 43). Mean platelet removal was 80.9 percent from units from which platelet concentrates were not prepared (n = 47). Microaggregates did not form during storage, and hemolysis of filtered red cells was lower than that of unfiltered controls. Filtered AS-3 red cells stored for 42 days had a 51Cr survival of 80.1 +/- 5.7 percent (mean +/- SD) as compared with 78.9 +/- 6.2 percent for unfiltered controls (n = 17). This in-line filter system provides white cell-depleted, microaggregate-free red cells that can be stored for 42 days.

Adenosine Triphosphate↗
PubMedDate not supplied

Improvement of bypass circuit biocompatibility: comparison and combination of heparin-coated circuit and nitric oxide gas infusion.

OBJECTIVES: Nitric oxide (NO) gas infusion to the oxygenator, as well as heparin-coated bypass circuits, have been reported to attenuate blood activation induced by the interaction with the artificial surfaces of an extracorporeal bypass circuit. Using a mock circulation model, we compared the effect of each and also evaluated the effect of their combination on attenuating bypass-induced blood activation. METHODS: A miniature closed bypass circuit was primed with diluted fresh human blood and perfused for 180 minutes using a centrifugal pump. NO gas (0, 50, or 100 ppm) was infused to the oxygenator sweep gas of either a non-heparin-coated or a heparin-coated circuit. Platelet counts, beta-thromboglobulin, platelet factor 4, complement-3 activation products and granulocyte elastase were measured at 0, 30, 60, 120, and 180 minutes after starting the perfusion. RESULTS: One hundred ppm of NO was statistically equivalent to the heparin-coated circuit for attenuating bypass-induced blood activation, and a combination of the two significantly surpassed the results of either modification alone. Fifty ppm of NO alone provided only a slight attenuation of blood activation as compared with the non-heparin-coated circuit, though the difference was not significant. A combination of 50 ppm NO and the heparin-coated circuit did not significantly enhance the effects of the heparin-coated circuit alone. CONCLUSIONS: The combination of NO gas infusion and heparin-coated circuits appears to be a useful and promising modification for enhancing the attenuation of bypass-induced blood activation, though the optimal dose of NO infusion in terms of effectiveness and adverse effects to the whole body remains to be established.

Anticoagulants↗
PubMed2003

Middle molecules and small-molecular-weight proteins in ESRD: properties and strategies for their removal.

Molecular weight has traditionally been the parameter most commonly used to classify uremic toxins, with a value of approximately 500 Da frequently used as a demarcation point below which the molecular weights of small nitrogenous waste products fall. This toxin group, the most extensively studied from a clinical perspective, is characterized by a high degree of water solubility and the absence of protein binding. However, uremia is mediated by the retention of a plethora of other compounds having characteristics that differ significantly from those of the previously mentioned group. As opposed to the relative homogeneity of the nitrogenous metabolite class, other uremic toxins collectively are a very heterogeneous group, not only with respect to molecular weight but also other characteristics, such as protein binding and hydrophobicity. A recently proposed classification scheme by the European Uraemic Toxin Work Group subdivides the remainder of molecules into 2 categories: protein-bound solutes and middle molecules. For the latter group, the Work Group proposes a molecular weight range (500-60,000 Da) that incorporates many toxins identified since the original middle molecule hypothesis, for which the upper molecular weight limit was approximately 2,000 Da. In fact, low-molecular-weight peptides and proteins (LMWPs) comprise nearly the entire middle molecule category in the new scheme. The purpose of this article is to provide an overview of the middle molecule class of uremic toxins, with the focus on LMWPs. A brief review of LMWP metabolism under conditions of normal (and in a few cases, abnormal) renal function will be presented. The physical characteristics of several LMWPs will also be presented, including molecular weight, conformation, and charge. Specific LMWPs to be covered will include beta 2-microglobulin, complement proteins (C3a and Factor D), leptin, and proinflammatory cytokines. The article will also include a discussion of the treatment-related factors influencing dialytic removal of middle molecules. Once these factors, which include membrane characteristics, protein-membrane interactions, and solute removal mechanisms, are discussed, an overview of the different therapeutic strategies used to enhance clearance of these compounds is provided.

Absorption↗
PubMed2001

Concentration of the complement activation product, acylation-stimulating protein, is related to C-reactive protein in patients with type 2 diabetes.

Type 2 diabetes is characterized by increased acute phase serum proteins. We wanted to study how these proteins are related to complement activation in type 2 diabetes and how improvement of glycemic control affects them or complement activation. A total of 29 type 2 diabetic patients (age, 55.2 +/- 1.8 years, glycosylated hemoglobin [HbA(1c)] 8.9% +/- 0.2%, body mass index [BMI] 30.9 +/- 0.8 kg/m(2), duration 5.9 +/- 1.3 years) participated in the study. They were previously treated either with diet alone or in combination with 1 oral antihyperglycemic medication. After a period of at least 4 weeks run-in on diet only, the patients were randomized to pioglitazone, glibenclamide, or placebo. Blood samples were taken before the treatments and at the end of the 6-month therapy. Basal C-reactive protein (CRP) level was related to acylation-stimulating protein (ASP) concentration (r =.55, P <.01), and many acute phase serum protein concentrations were associated with each other. The treatment reduced HbA(1c) level in the pioglitazone (from 9.1 +/- 0.3% to 8.0 +/- 0.5%, P <.05) and glibenclamide (from 8.9 % +/- 0.3% to 7.7% +/- 0.2%, P <.05) groups. Glibenclamide treatment was associated with a reduction in alpha-1-antitrypsin (P <.05), ceruloplasmin (P <.01), and complement C3 protein (C3) (P <.05). Although ASP did not change significantly in any of the treatment subgroups, in the whole patient population, the change in HbA(1c) during the treatments correlated positively with the change in ASP, (r =.43, P <.05). The changes in many acute phase serum proteins and ASP were related to each other. In conclusion, (1) inflammatory factors and complement activation are associated in patients with type 2 diabetes, and (2) changes in hyperglycemia are related to changes in the concentration of the complement activation product, ASP.

Acute-Phase Proteins↗
PubMed1985

Serum sickness.

Explore the source record for details and available documents.

Complement C3↗
PubMed1998

Chylomicron-specific enhancement of acylation stimulating protein and precursor protein C3 production in differentiated human adipocytes.

Acylation stimulating protein (ASP) is a potent stimulator of adipocyte triacylglycerol storage. In vivo studies have shown that ASP production by adipocytes increases locally after a fat meal. Initial in vitro studies demonstrated increased production of ASP in the presence of chylomicrons (CHYLO). The present aim was to define the CHYLO component responsible. None of the apoproteins tested (AI, AII, AIV, CI, CII, CIII, and E) were capable of stimulating C3 (the precursor protein) or ASP production. Rather, the active component is a nonlipid, loosely associated, trypsin-sensitive molecule. High pressure liquid chromatography fractionation of the CHYLO infranate proteins identified the critical protein as transthyretin (TTR), which binds retinol-binding protein and complexes thyroxine and retinol. Addition of TTR alone, with lipid emulsion, or with respun CHYLO to human differentiated adipocytes had little effect on C3 and ASP production. By contrast, when transthyretin was added to CHYLO, C3 and ASP production were substantially enhanced up to 75- and 7. 5-fold respectively, compared with the effect of native CHYLO alone. Finally, a polyclonal antibody against TTR could inhibit stimulation of C3 and ASP production by CHYLO (by 98 and 100%, respectively) and by CHYLO infranate proteins (by 99 and 94%, respectively). We hypothesize that TTR mediates the transfer of the active components from CHYLO to adipocytes, which then stimulates increased C3 and ASP production. Thus the CHYLO provides the physiologic trigger of the ASP pathway.

Adipocytes↗
PubMed1999

Mechanisms involved in the regulation of free fatty acid release from isolated human fat cells by acylation-stimulating protein and insulin.

The effects of acylation-stimulating protein (ASP) and insulin on free fatty acid (FFA) release from isolated human fat cells and the signal transduction pathways to induce these effects were studied. ASP and insulin inhibited basal and norepinephrine-induced FFA release by stimulating fractional FFA re-esterification (both to the same extent) and by inhibiting FFA produced during lipolysis (ASP to a lesser extent than insulin). Protein kinase C inhibition influenced none of the effects of ASP or insulin. Phosphatidylinositol 3-kinase inhibition counteracted the effects of insulin but not of ASP. Phosphodiesterase 3 (PDE3) activity was stimulated by ASP and insulin, whereas PDE4 activity was slightly increased by ASP only. Selective PDE3 inhibition reversed the effects of both ASP and insulin on fractional FFA re-esterification and lipolysis. Selective PDE4 inhibition slightly counteracted the ASP but not the effect of insulin on fractional FFA re-esterification and did not prevent the action of ASP or insulin on lipolysis. Thus, ASP and insulin play a major role in regulating FFA release from fat cells as follows: insulin by stimulating fractional FFA re-esterification and inhibiting lipolysis and ASP mainly by stimulating fractional FFA re-esterification. For both ASP and insulin these effects on FFA release are mediated by PDE3, and for ASP PDE4 might also be involved. The signaling pathway preceding PDE is not known for ASP but involves phosphatidylinositol 3-kinase for insulin.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1999

Genetic deficiency of acylation stimulating protein (ASP(C3ades-Arg)) does not cause hyperapobetalipoproteinemia in mice.

The acylation stimulating protein (ASP) is a 76-amino acid peptide that has been proposed as a potent mediator of triglyceride synthesis and, when functionally impaired, as a major cause of hyperapobetalipoproteinemia (HyperapoB). Purification and sequence analysis of ASP from human sera have revealed that ASP is identical to the complement C3-derived activation peptide C3ades-Arg. Because C3 is the precursor for C3ades-Arg and therefore ASP, a deficiency in C3 would be predicted to result in a phenotype characteristic of HyperapoB. To test this hypothesis in vivo, the current study was undertaken in which ASP(C3ades-Arg)-deficient mice were used as a model system. No significant differences were found in the triglyceride, cholesterol, or free fatty acid concentrations in the plasma of fasted normal and ASP(C3ades-Arg)-deficient animals. In addition, plasma lipoprotein analyses indicated that the very low density lipoprotein, low density lipoprotein, and high density lipoprotein cholesterol and triglyceride concentrations as well as the apolipoprotein B-48 and B-100 levels were not significantly different in the plasma of ASP(C3ades-Arg)-deficient and wild type mice. Furthermore, when challenged with an oral fat load, the ASP(C3ades-Arg)-deficient mice showed no impaired ability to clear triglycerides and free fatty acids from their circulation when compared with their wild-type littermates. Collectively, these results indicate that ASP(C3ades-Arg) deficiency does not cause HyperapoB in mice and that the physiological importance of impaired ASP(C3ades-Arg) function as a cause of hyperapobetalipoproteinemia needs to be reevaluated.

Animals↗
PubMed1999

Acylation stimulating protein (ASP) deficiency alters postprandial and adipose tissue metabolism in male mice.

Acylation stimulating protein (ASP) is a potent stimulator of triglyceride synthesis in adipocytes. In the present study, we have examined the effect of an ASP functional knockout (ASP(-/-)) on lipid metabolism in male mice. In both young (14 weeks) and older (26 weeks) mice there were marked delays in postprandial triglyceride clearance (80% increase at 14 weeks and 120% increase at 26 weeks versus wild type (+/+)). Postprandial nonesterified fatty acids were also increased in ASP(-/-) mice versus ASP(+/+) mice by 37% (low fat 10% Kcal) and by 73% (high fat 40% Kcal) diets, although there were no differences in fasting lipid levels. The ASP(-/-) mice had moderately increased energy intake (16% +/- 2% p < 0.0001) and reduced feed efficiency (33% increase in calories/g of body weight gained on low fat diet) versus wild type. The ASP(-/-) mice also had modest changes in insulin/glucose metabolism (30% to 40% decrease in insulin.glucose product), implying increased insulin sensitivity. As well, there were decreases in leptin (29% shift in leptin to body weight ratio) and up to a 26% decrease in specific adipose tissue depots versus the wild type mice on both low fat and high fat diets. These results demonstrate that ASP plays an important role in adipose tissue metabolism and fat partitioning.

Adipose Tissue↗
PubMed2002

Acylation-stimulating protein (ASP) deficiency induces obesity resistance and increased energy expenditure in ob/ob mice.

Acylation-stimulating protein (ASP) acts as a paracrine signal to increase triglyceride synthesis in adipocytes. ASP administration results in more rapid postprandial lipid clearance. In mice, C3 (the precursor to ASP) knockout results in ASP deficiency and leads to reduced body fat and leptin levels. The protective potential of ASP deficiency against obesity and involvement of the leptin pathway were examined in ob/ob C3(-/-) double knockout mice (2KO). Compared with age-matched ob/ob mice, 2KO mice had delayed postprandial triglyceride and fatty acid clearance; associated with decreased body weight (4-17 weeks age: male: -13.7%, female: -20.6%, p < 0.0001) and HOMA (homeostasis model assessment) index (-37.7%), suggesting increased insulin sensitivity. By contrast, food intake in 2KO mice was +9.1% higher over ob/ob mice (p < 0.001, 2KO 5.1 +/- 0.2 g/day, ob/ob 4.5 +/- 0.2 g/day, wild type 2.6 +/- 0.1 g/day). The hyperphagia/leanness was balanced by a 28.5% increase in energy expenditure (oxygen consumption: 2KO, 131 +/- 8.9 ml/h; ob/ob, 102 +/- 4.5 ml/h; p < 0.01; wild type, 144 +/- 8.9 ml/h). These results suggest that the ASP regulation of energy storage may influence energy expenditure and dynamic metabolic balance.

Animals↗
PubMed2003

Acylation-stimulating protein (ASP)/complement C3adesArg deficiency results in increased energy expenditure in mice.

Acylation-stimulating protein (ASP) acts as a paracrine signal to increase triglyceride synthesis in adipocytes. In mice, C3 (the precursor to ASP) knock-out (KO) results in ASP deficiency and leads to reduced body fat and leptin levels yet they are hyperphagic. In the present study, we investigated the mechanism for this energy repartitioning. Compared with wild-type (WT) mice, male and female C3(-/-) ASP-deficient mice had elevated oxygen consumption (VO2) in both the active (dark) and resting (light) phases of the diurnal cycle: +8.9% males (p < 0.05) +9.4% females (p < 0.05). Increased physical activity (movement) was observed during the dark phase in female but not in male KO animals. Female WT mice moved 16.9 +/- 2.4 m whereas KO mice moved 30.1 +/- 5.4 m, over 12 h, +78.4%, p < 0.05). In contrast, there was no difference in physical activity in male mice, but a repartitioning of dietary fat following intragastric fat administration was noted. This was reflected by increased fatty acid oxidation in liver and muscle in KO mice, with increased UCP2 (inguinal fat) and UCP3 (muscle) mRNA expression (p = 0.005 and 0.036, respectively). Fatty acid uptake into brown adipose tissue (BAT) and white adipose tissue (WAT) was reduced as reflected by a decrease in the fatty acid incorporation into lipids (BAT -68%, WAT -29%. The decrease of FA incorporation was normalized by intraperitoneal administration of ASP at the time of oral fat administration. These results suggest that ASP deficiency results in energy repartitioning through different mechanisms in male and female mice.

Adipose Tissue↗
PubMed1997

The acylation-stimulating protein pathway and regulation of postprandial metabolism.

Much has recently been learned about the processes involved in postprandial triacylglycerol clearance. As discussed previously, important differences in the metabolism of chylomicrons and VLDL have become apparent. The ASP pathway has also been recognized and appears to play a critical role in chylomicron metabolism. The ASP pathway is activated in order to trap the fatty acids released from chylomicrons by the action of LPL and there is now unequivocal in vivo evidence in human subjects that ASP is generated by adipocytes in the postprandial period. These findings match the in vitro data showing that chylomicrons, but not the other plasma lipoproteins or fatty acids, activate the generation of ASP by cultured human adipocytes. An inverse relationship appears to exist between the proportion of fatty acids taken up by adipocytes and that released into the general circulation. Too great a release into the general circulation because of diminished trapping of fatty acids released from chylomicrons appears to be critical in the pathogenesis of the dyslipoproteinaemias associated with hyperapo B or FCHL and omental obesity. Evidence has been presented that dysfunction of the ASP pathway may be one of the causes of this disorder. Put differently, the ASP pathway is essential for the normal clearance and disposition of dietary fatty acids. Binding of chylomicrons to capillary endothelium followed by lipolysis by LPL results in the sudden liberation of fatty acids, and in the marked generation of ASP by adipocytes. The ASP that is generated is essential if LPL is to continue to form fatty acids at a normal rate. It is essential also if the fatty acids which are formed are to enter the adipocyte rather than exit into the general circulation. The transport vehicle, the chylomicron, therefore stimulates the formation of the peptide, ASP, which is responsible for its successful metabolism. Thus, the ASP pathway provides the metabolic coordination between the chylomicron and the adipocyte, which we describe as microenvironmental metabolic regulation and which we believe is essential for the normal clearance of dietary triacylglycerol from plasma.

Adipocytes↗
PubMed2003

Studies of adipose tissue metabolism in human immunodeficiency virus-associated lipodystrophy.

We studied aspects of metabolism in subcutaneous adipose tissue (SAT) in 40 human immunodeficiency virus (HIV)-infected subjects with and without lipodystrophy and in healthy control subjects. HIV-infected subjects without lipodystrophy had less SAT and visceral adipose tissue (VAT). Glycerol release was higher in both HIV-infected groups, especially those without fat redistribution. Tumor necrosis factor (TNF) release from SAT and serum soluble TNF receptor 2 concentrations were significantly higher in HIV-infected individuals with lipodystrophy. The absolute production of acylation-stimulating protein (ASP) and the percentage conversion of the complement protein to ASP were significantly lower in HIV-infected subjects with lipodystrophy. Further studies are needed to dissect the factors that mediate lipoatrophy in HIV infection.

Adipose Tissue↗
PubMed2004

Addition of glucose to an oral fat load reduces postprandial free fatty acids and prevents the postprandial increase in complement component 3.

BACKGROUND: Elevated fasting plasma concentrations of complement component 3 (C3) are associated with elevated fasting and postprandial triacylglycerol concentrations, insulin resistance, obesity, and coronary artery disease. C3 is the central component of the complement system and the precursor of acylation-stimulating protein (ASP). Insulin and ASP are principal determinants of free fatty acid (FFA) trapping by adipose tissue. OBJECTIVE: Because controversy exists concerning postprandial changes in C3 and because meal composition may influence complement activation, we studied postprandial lipemia in relation to changes in plasma C3. DESIGN: After an overnight fast, 6 healthy men ( +/- SD age: 23 +/- 2 y) underwent 4 oral liquid challenges: fat (50 g/m(2) body surface), glucose (37.5 g/m(2)), fat and glucose (mixed test), and water (as a control test) in a random, crossover design. RESULTS: Plasma ASP concentrations did not change postprandially in any test. Changes in C3 concentration were observed only after the fat challenge: elevated concentrations occurred between 1 and 3 h, and a maximum increase of 11% occurred at 2 h (P = 0.05). Postprandial triacylglycerolemia did not differ significantly between the fat and mixed tests. The FFA response after the fat challenge was the highest of all the tests (P < 0.05 for all comparisons) and was accompanied by an increase in ketone bodies (maximum at 6 h); this increase did not occur after the mixed test, which suggests less hepatic FFA delivery. CONCLUSIONS: When glucose is added to an oral fat load, the postprandial FFA response is reduced, and the fat-specific increase in C3 is prevented. After ingestion of fat without glucose, the lack of insulin response may lead to C3-mediated peripheral FFA trapping, which probably serves as a backup system in case of insufficient or inefficient insulin-dependent FFA trapping.

Adult↗
PubMedDate not supplied

Cervicovaginal opsonic activity, immunoglobulins, complement, and soluble fibronectin in healthy women randomly assigned to tampon or napkin use.

The effect of tampon use on cervicovaginal immunoglobulins, complement, fibronectin, and antistaphylococcal opsonic activity was determined in a study of 35 healthy women randomly allocated to either tampon or napkin use for three consecutive menstrual cycles. Sequential cervicovaginal washings were collected on days 3 (+/- 2), 15 (+/- 2), and 25 (+/- 2) of the menstrual cycle before randomization and that 3 months afterward. Prior to randomization, no statistically significant differences were noted for any parameter (with correction for total protein content) between regular tampon users and exclusive napkin users. Following randomization, total opsonic activity during tampon use increased significantly over that in the same women during napkin use (P = .04, Wilcoxon matched-pairs signed-ranks test, two-tailed). This difference was observed only in menstrual samples and not at other sampling times. These data indicate that tampon use has minimal effects on cervicovaginal mucosal immunity and is not associated with aberrations of opsonophagocytosis in the lower female genital tract.

Adult↗
PubMed1986

Inappropriate activation, deactivation, and probable autooxidative damage as a mechanism of neutrophil locomotory defect in trauma.

We studied 46 patients who suffered from serious blunt trauma to examine the possible mechanism of their acquired neutrophil (PMN) locomotory dysfunction. Concentrations of plasma C3adesArg were higher in patients than in controls (310 +/- 190 ng/ml vs. 90 +/- 28 ng/ml, respectively; P = 3 X 10(-5)). Both resting and phagocytosing PMNs from the patients produced higher quantities of H2O2 (0.31 +/- 0.29 and 5.2 +/- 3.4 nmol/10(6) PMNs per hr, respectively). These levels resemble the H2O2 production of normal PMNs preactivated with chemotactic factor (0.85 +/- 0.03 for normal and 8.2 +/- 1.6 nmol/10(6) PMNs per hr for preactivated PMNs). Concentrations of oxidized glutathione were not significantly higher in PMNs from patients compared with PMNs from controls (0.053 +/- 0.057 vs. 0.037 +/- 0.046 nmol/10(6) PMNs, respectively; P = .5). A higher percentage of PMNs from trauma patients than from controls were capped with concanavalin A (66% +/- 11% vs. 37% +/- 14%, respectively; P = 4 X 10(-5)), a result indicating microtubular dysfunction. These findings suggest that in trauma, activation of intravascular complement results in inappropriate chemotactic stimulation and subsequent deactivation and autoxidative damage of circulating PMNs.

Adolescent↗