Thyroid function in a population with an extra iodine intake]

Polymorphonuclear leukocyte (PMN) superoxide (.O2-) production has been implicated in the pathogenesis of cardiopulmonary bypass (CPB)-related end organ injury. PMN "priming" has been described as an event which enhances the release of .O2- following a second, activating insult. We hypothesized that PMN priming occurs during CBP and is temporally related to the plasma level of complement (C3a), interleukin (IL)-6, and IL-8. PMNs were isolated from 10 CPB patients pre-bypass (preCPB), 5 min after protamine administration (PROT), and at 6 and 24 h post-CPB. PMN .O2- production was measured by a cytochrome c reduction assay in the presence or absence of either phorbol 12-myristate-13-acetate (PMA, 0.4 microgram/ml) or N-formyl-methionyl-leucyl-phenylalanine (FMLP, 1 microM) and also after priming with 2000 nM platelet-activating factor (PAF) followed by activation with either PMA or FMLP. Plasma levels of C3a, IL-6, and IL-8 were determined by enzyme-linked immunosorbent assay. PMA-activated PMN .O2- production was significantly elevated at 6 h post-CPB compared to pre-CPB levels (11.04 +/- 0.9 vs 7.62 +/- 0.57, P = 0.009), indicating that CPB is associated with in vivo PMN priming. When PMNs were primed in vitro with PAF and then activated with PMA or FMLP, .O2- release at 6 h post-CPB was also significantly greater than pre-CPB levels (16.04 +/- 0.74 vs 12.2 +/- 0.92, P = 0.038; and 17.33 +/- 1.38 vs 13.33 +/- 1.35, P < 0.05), indicating that CPB acts synergistically with PAF to prime PMNs. Levels of C3a rose significantly over pre-CPB levels at PROT (P = 0.001), and IL-6 and IL-8 rose over pre-CPB levels at 6 h post-CPB (P = 0.01 and P = 0.006, respectively). These findings demonstrate that CPB not only directly primes PMNs, but also potentiates priming of PMNs by PAF. This "primed" PMN state, which coincided with the increased plasma levels of inflammatory mediators, may suggest a mechanism of predisposition to organ dysfunction following CPB.     

Postinjury neutrophil priming and activation: an early vulnerable window

BACKGROUND: Generation of extracellular, cytotoxic superoxide anion (O2-) by polymorphonuclear neutrophils (PMNs) contributes to an unbridled inflammatory response that can precipitate multiple organ failure (MOF). Release of O2- is markedly enhanced when activated PMNs have been previously "primed" by inflammatory mediators, such as those expressed after trauma. We therefore hypothesized that PMN priming occurs as an integral part of the early inflammatory response to trauma. METHODS: PMNs were obtained from 17 high-risk patients with torso trauma at 3, 6, 12, 24, 48, and 72 hours after injury, as well as from 10 healthy donors, and the in vitro release of O2- was quantitated with a kinetic, superoxide dismutase (SOD)-inhibitable cytochrome c reduction assay. PMN O2- release was measured in the presence and absence of 1 mumol/L N-formyl-methionyl-leucyl-phenylalanine (fMLP) and after priming and activation with 20 nmol/L platelet-activating factor (PAF) and 1 mumol/L fMLP, respectively. RESULTS: In vitro PMN O2- release was used to determine whether postinjury PMNs were (1) activated in vivo, (2) primed in vivo, or (3) primable in vitro. Unstimulated PMNs from trauma patients spontaneously expressed modest amounts of O2- in vitro from 6 to 48 hours after injury, suggesting endogenous activation. Also, fMLP-activated PMNs collected between 3 and 24 hours after injury expressed more O2- than controls (p < or = 0.02), indicating in vivo, trauma-related priming. Furthermore, postinjury PMNs were maximally primed in vivo (i.e., in vitro exposure to PAF before fMLP activation failed to significantly enhance O2- release) as compared to PMNs treated with fMLP. CONCLUSIONS: These data indicate that major torso trauma (first hit) primes and activates PMNs within 3 to 6 hours after injury. Consequently, we postulate that postinjury priming of PMNs may create an early vulnerable window during which a second hit (e.g., a secondary operation or delayed hemorrhage) activates exuberant PMN O2- release, rendering the injured patient at high risk for MOF.     

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.     

Cefepime versus imipenem-cilastatin as empirical monotherapy in 400 febrile patients with short duration neutropenia. CEMIC (Study Group of Infectious Diseases in Cancer)

Interleukin-8 (IL-8) priming was studied in neutrophils to examine its dependency on altered calcium fluxes and for similarity to lipopolysaccharide (LPS). IL-8 caused a rapid rise in [Ca2+]i that returned to baseline values by 20 min. Peak [Ca2+]i transients in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP) were unaltered in IL-8-primed compared with unprimed cells. In comparison to LPS and tumor necrosis factor (TNF), IL-8 was a much weaker priming agent as measured by either O2- or H2O2 production. Despite their large disparity in potency, IL-8 and LPS printing were additive using fMLP, a receptor-dependent stimulator, and synergistic using the post-receptor, protein kinase C activator, phorbol 12-myristate 13-acetate (PMA) to trigger the respiratory burst. In contrast, IL-8 and TNF priming were synergistic for fMLP (P = 0.05), but completely nonadditive when PMA was used as the neutrophil stimulant (P = 0.05 for subadditivity). Thus, lasting alterations in [Ca2+]i are not a necessary characteristic of IL-8-primed cells. IL-8 and LPS appear to prime by non-overlapping pathways, whereas IL-8 and TNF appear to share mechanisms distal to protein kinase C activation. IL-8 and LPS may independently contribute to neutrophil-mediated host defense or injury by priming through distinct pathways.     

Acute inflammatory response in the mouse: exacerbation by immunoneutralization of lipocortin 1

1. An immuno-neutralization strategy was employed to investigate the role of endogenous lipocortin 1 (LC1) in acute inflammation in the mouse. 2. Mice were treated subcutaneously with phosphate-buffered solution (PBS), non-immune sheep serum (NSS) or with one of two sheep antisera raised against LC1 (LCS3), or its N-terminal peptide (LCPS1), three times over a period of seven days. Twenty four hours after the last injection several parameters of acute inflammation were measured including zymosan-induced inflammation in 6-day-old air-pouches, zymosan-activated serum (ZAS)-induced oedema in the skin, platelet-activating factor (PAF)-induced neutrophilia and interleukin-1 beta (IL-1 beta)-induced corticosterone (CCS) release. 3. At the 4 h time-point of the zymosan inflamed air-pouch model, treatment with LCS3 did not modify the number of polymorphonuclear leucocytes (PMN) recruited: 7.84 +/- 1.01 and 7.00 +/- 0.77 x 10(6) PMN per mouse for NSS- and LCS3 group, n = 7. However, several other parameters of cell activation including myeloperoxidase (MPO) and elastase activities were increased (2.2 fold, P < 0.05, and 6.5 fold, P < 0.05, respectively) in the lavage fluids of these mice. Similarly, a significant increase in the amount of immunoreactive prostaglandin E2 (PGE2; 1.81 fold, P < 0.05) and IL-1 alpha (2.75 fold, P < 0.05), but not tumour necrosis factor-alpha (TNF-alpha), was also observed in LCS3-treated mice. 4. The recruitment of PMN into the zymosan inflamed air-pouches by 24 h had declined substantially (4.13 +/- 0.61 x 10(6) PMN per mouse, n = 12) in the NSS-treated mice, whereas high values were still measured in those treated with LCS3 (9.35 +/- 1.20 x 10(6) PMN per mouse, n = 12, P < 0.05). A similar effect was also found following sub-chronic treatment of mice with LCPS1: 6.48 +/- 0.10 x 10(6) PMN per mouse, vs. 2.77 +/- 1.20 and 2.64 +/- 0.49 x 10(6) PMN per mouse for PBS- and NSS-treated groups (n = 7, P < 0.05). Most markers of inflammation were also increased in the lavage fluids of LCS3-treated mice: MPO and elastase showed a 2.47 fold and 17 fold increase, respectively (P < 0.05 in both cases); TNF-alpha showed a 11.1 fold increase (P < 0.05) whereas the IL-1 alpha levels were not significantly modified. PGE2 was still detectable in most (5 out of 7) of the mice treated with LCS3 but only in 2 out of 7 of the NSS-treated mice. 5. Intradermal injection of 50% ZAS caused a significant increase in the 2 hoedema formation in the skin of LCS3-treated mice in comparison to PBS- and NSS-treated animals: 16.7 +/- 1.5 microliters vs. 10.8 +/- 1.2 microliters and 10.2 +/- 1.0 microliters, respectively (n = 14 mice per group, P < 0.05). ZAS-induced oedema had subsided by 24 h in control animals but a residual significant amount of extravasation was still detectable in LCS3-treated mice: 4.4 +/- 0.8 microliters (P < 0.05). 6. A recently described model driven by endogenous glucocorticoids is the blood neutrophilia observed following administration of PAF. In our experimental conditions, a single bolus of PAF (100 ng, i.v.) provoked a marked neutrophilia at 2 h (2.43 and 2.01 fold) in NSS- and PBS-treated mice (n = 11), respectively, which was significantly attenuated in the animals treated with LCS3: 1.26 fold increase in circulating PMN (n = 11, P < 0.01 vs. NSS- and PBS-groups). 7. Intraperitoneal injection of IL-1 beta (5 micrograms kg-1) caused a marked increase in circulating plasma CCS by 2 h, to a similar extent in all experimental groups. In contrast, measurement of CCS levels in the plasma of mice bearing air-pouches inflamed with zymosan revealed significant differences between LCS3 and NSS-treated mice at the 4 h time-point: 198 +/- 26 ng ml-1 vs. 110 +/- 31 ng ml-1 (n = 8, P < 0.05). 8. In conclusion, we found a remarkable exacerbation of the inflammatory process with respect to both humoral and cellular components in mice passively immunised agains     

Leukocyte adhesion molecules in the liver and plasma cytokine levels in endotoxin-induced rat liver injury

BACKGROUND: The interactions between polymorphonuclear neutrophils (PMNs) and sinusoidal endothelial cells (SECs) have been known to be involved in the pathogenesis of acute liver injury. It has been also reported that tumor necrosis factor-alpha (TNF-alpha) up-regulates ICAM-1 expression on SECs and that interleukin-8 (IL-8) provokes rapid activation of CD11/CD18 on PMNs. These findings expand into the relationship between the expression of leukocyte adhesion molecules (ICAM-1, CD11a/CD18 and CD11b/CD18) in liver tissues and plasma TNF and IL-8 levels after lipopolysaccharide (LPS)-induced liver injury in rats. METHODS: Male Wistar rats weighing 200-250 g were treated with 2 mg LPS/kg intravenously in a 0.2- to 0.25-ml volume. Liver and blood samples were obtained at 1, 3, 8, and 12 h after LPS exposure. Plasma TNF and IL-8 levels were measured using bioassay and specific enzyme-linked immunosorbent assay, respectively. Liver samples were fixed and studied by immunohistochemistry using specific monoclonal antibodies against ICAM-1, CD11a, and CD11b. RESULTS: The TNF level showed a peak at 1 h (23.3 +/- 11.4 IU/ml), and the IL-8 level showed a peak at 3 h (343.1 +/- 110.5 ng/ml) after LPS exposure. An increase in the number of PMNs in the liver was observed as early as 1 h and continued until 12 h after LPS exposure. PMNs adhered to degenerated SECs and hepatocytes. ICAM-1 on SECs was diffusely and strongly expressed at 8 h, and PMNs adhered to SECs expressed both CD11a and CD11b. ICAM-1 was also observed on hepatocytes. CONCLUSION: These data suggest that PMN-SEC and PMN-hepatocyte interactions via leukocyte adhesion molecules, related to inflammatory cytokines such as TNF and IL-8, exist and play an important role in the pathogenesis of acute liver injury.     

Interleukin-8 (IL-8), melanoma growth-stimulatory activity, and neutrophil-activating peptide selectively mediate priming of the neutrophil NADPH oxidase through the type A or type B IL-8 receptor

The capacity of neutrophils to generate superoxide (O-2) can be enhanced by prior exposure to "priming" agents such as interleukin-8 (IL-8), melanoma growth-stimulatory activity (MGSA), and neutrophil-activating peptide (ENA-78). The biological effects of these chemokines are mediated by at least two distinct receptors: type A (IL-8-RA) and type B (IL-8-RB). Using neutralizing monoclonal antibodies to IL-8-RA and IL-8-RB, we have investigated the contribution each receptor makes to the priming response. Preincubation with IL-8, MGSA, or ENA-78 enhanced the ability of neutrophils to generate O-2 following stimulation with the bacterial peptide formyl-Met-Leu-Phe. The priming effect of IL-8 was eliminated by an anti-IL-8 monoclonal antibody (mAb) that is known to bind IL-8 with high affinity and prevent receptor occupancy. Incubation of neutrophils with a neutralizing mAb specific for IL-8-RA blocked IL-8-induced priming but had no effect on priming by MGSA or ENA-78. In contrast, treatment with a neutralizing mAb specific for IL-8-RB failed to inhibit the priming effect of IL-8 but blocked both MGSA and ENA-78-induced priming. These observations indicate that the priming effect of IL-8 on the neutrophil respiratory burst is predominantly mediated via IL-8-RA, whereas priming by MGSA and ENA-78 is mediated by IL-8-RB.     

Platelet-activating factor synthesized by IL-12-stimulated polymorphonuclear neutrophils and NK cells mediates chemotaxis

IL-12 is chemotactic for NK cells and polymorphonuclear neutrophils (PMN), but not for monocytes. In the present study, we evaluated whether the chemotactic effect of IL-12 is a direct phenomenon or is dependent on the generation of secondary mediators. The results obtained indicate that IL-12 induces a dose- and time-dependent synthesis of platelet-activating factor (PAF) from PMN and NK cells and of reactive oxygen radicals (ROS) from PMN. Monocytes and CD56-negative PBMC cells did not synthesize PAF or ROS after challenge with IL-12. The production of ROS by PMN was significantly inhibited by two chemically different PAF receptor antagonists (WEB 2170 and CV 3988), suggesting an autocrine stimulation of PMN by PAF newly synthesized after the challenge with IL-12. Moreover, the IL-12-induced chemotaxis of PMN and NK cells was significantly reduced by both WEB 2170 and CV 3988, suggesting that synthesized PAF mediates the chemotactic effect of IL-12. Preincubation with superoxide dismutase, which blocks the formation of superoxide anions, also reduced the chemotactic effect of IL-12 on PMN, but not on NK cells, suggesting that superoxide anion generation is relevant only for the IL-12-induced chemotaxis of PMN. In conclusion, the results of the present study indicate that IL-12-induced PAF synthesis plays a critical role in triggering the events involved in the motogenic response of PMN and NK to IL-12.     

The biphasic mRNA expression pattern of bovine interleukin-8 in Pasteurella haemolytica lipopolysaccharide-stimulated alveolar macrophages is primarily due to tumor necrosis factor alpha

Pasteurella haemolytica serotype 1 is the bacterial agent responsible for the pathophysiological events associated with bovine pneumonic pasteurellosis. Our previous studies support a role for the lipopolysaccharide (LPS) from P. haemolytica in the induction of proinflammatory cytokines. One of the pathological hallmarks of bovine pneumonic pasteurellosis is an influx of neutrophils into the alveolar spaces. This pronounced influx suggests the local production of a chemotactic factor(s) such as interleukin-8 (IL-8). In the context of the lung, the alveolar macrophage appears to be the major producer of IL-8, a proinflammatory cytokine with potent neutrophil chemotactic activity. By using Northern blot analysis, we have examined the kinetics of IL-8 mRNA expression in P. haemolytica LPS-stimulated bovine alveolar macrophages and found that 1 ng of LPS per ml induces maximal expression of IL-8 mRNA. The results also indicate a biphasic time course expression pattern in which IL-8 mRNA levels peak between 1 and 2 h in the first phase and between 16 and 24 h in the second phase (P < 0.01). In addition, monospecific polyclonal antibodies were used to demonstrate the role of tumor necrosis factor alpha (TNF-alpha) in the second phase of IL-8 mRNA expression. Our findings support a role for P. haemolytica LPS and TNF-alpha in the induction of IL-8 from bovine alveolar macrophages.     

Production of interleukin-8 (IL-8) by cultured endothelial cells in response to Borrelia burgdorferi occurs independently of secreted [corrected] IL-1 and tumor necrosis factor alpha and is required for subsequent transendothelial migration of neutrophils

Previous studies have shown that Borrelia burgdorferi, the spirochetal agent of Lyme disease, promotes inflammation by stimulating endothelial cells to upregulate adhesion molecules for leukocytes and to produce a soluble agent that is chemotactic for neutrophils. We determined that interleukin-8 (IL-8) was the chemotactic agent for neutrophils present in conditioned media from cultured human umbilical vein endothelial cells stimulated with B. burgdorferi. As few as one spirochete per endothelial cell stimulated production of IL-8 within 8 h of coincubation. When 10 spirochetes per endothelial cell were added, IL-8 was detected after 4 h of coculture. Production of IL-8 continued in a linear fashion for at least 24 h. Neutralizing antibodies against IL-8 reduced migration of neutrophils across spirochete-stimulated endothelial monolayers by 93%. In contrast, pretreatment of neutrophils with antagonists of platelet-activating factor did not inhibit migration. Increases in production of IL-8 and expression of the adhesion molecule E-selectin by endothelial cells in response to B. burgdorferi were not inhibited by IL-1 receptor antagonist or a neutralizing monoclonal antibody directed against tumor necrosis factor alpha, used either alone or in combination. These results suggest that activation of endothelium by B. burgdorferi is not mediated through the autocrine action of secreted IL-1 or tumor necrosis factor alpha. Rather, it appears that B. burgdorferi must stimulate endothelium either by a direct signaling mechanism or by induction of a novel host-derived proinflammatory cytokine.     

The platelet-activating factor antagonist BN 52021 attenuates hypoxic-ischemic brain injury in the immature rat

Platelet-activating factor (PAF) is overproduced in ischemic brain. Although postischemic PAF antagonist administration protects the mature brain in some models, little is known about the effects of PAF antagonists in the immature brain. We hypothesized that the PAF antagonist BN 52021 would attenuate perinatal cerebral hypoxic-ischemic injury. To elicit focal hypoxic-ischemic brain injury, 7-d-old (P7) rats (n = 111) underwent right carotid ligation, followed by 2.5-3.25 h of hypoxia (fractional concentration of inspired O2 = 0.08). BN 52021 neuroprotection was evaluated in three groups of experiments: 1) 25 mg/kg/dose, 0 and 2 h posthypoxia; 2), 25 mg/kg/dose immediately before and 1 h after hypoxia; and 3) posthypoxia-ischemia treatment with BN 52021 12.5, 25, or 50 mg/kg/dose in 2 doses 0 and 2 h after hypoxia. All experiments included concurrent vehicle-injected controls. To quantitate severity of injury, bilateral regional cross-sectional areas (groups 1 and 2) or hemisphere weights (group 3) were evaluated on P12. Both pre- and posthypoxic treatment with BN 52021 (25 mg/kg/dose, two serial doses) decreased the incidence of cerebral infarction from 90% to about 30% (p < 0.02, Fisher's exact test). Measurement of cross-sectional areas confirmed neuroprotection and indicated some benefit of pre- over posthypoxic-ischemic treatment in hippocampus and cortex. Over the dose range tested, the neuroprotective effect of BN 52021 administration was not dose-dependent. In contrast, BN 52021 did not attenuate N-methyl-D-aspartate-induced hippocampal excitotoxic injury in P7 rats. Either prophylactic or "rescue" administration of PAF antagonists decreases the incidence and severity of brain injury associated with an episode of perinatal cerebral hypoxia-ischemia.     

Priming induces functional coupling of N-formyl-methionyl-leucyl-phenylalanine receptors in equine neutrophils

The synthetic formylpeptide fMLP is widely used as a model chemoattractant and secretagogue for mammalian neutrophils. Despite possessing fMLP receptors, equine neutrophils do not produce superoxide anions in response to fMLP and there is no inflammatory reaction in the horse when fMLP is injected intradermally. The functional capability of these receptors was investigated after pretreatment with recognized priming agents. Purified neutrophils were pretreated with lipopolysaccharide (LPS), platelet-activating factor (PAF), or tumor necrosis factor alpha (TNF-alpha) and superoxide anion generation and shape change quantified by lucigenin-dependent chemiluminescence (LDCL) and flow cytometry, respectively. LPS, TNF-alpha, and PAF pretreatment induced significant LDCL in response to fMLP; similarly LPS pretreatment was a prerequisite for fMLP-stimulated neutrophil polarization in response to fMLP. However, LPS failed to induce fMLP-mediated chemotaxis of equine neutrophils. These data indicate that equine neutrophil fMLP receptors are not vestigial as previously thought but can trigger both respiratory burst activity and cell polarization responses after priming.     

Changes in plasma erythropoietin and interleukin-6 concentrations in patients with septic shock after hemoperfusion with polymyxin B-immobilized fiber

OBJECTIVE: To find out whether polymyxin B-immobilized fiber (PMX-F) treatment affects the clinical parameters and plasma concentrations of erythropoietin (EPO) and interleukin (IL)-6. DESIGN: A prospective case series study. SETTING: Intensive care unit of the Department of Internal Medicine, Misato Junshin Hospital, Saitama, and Koto Hospital, Tokyo, Japan. PATIENTS: 17 consecutive patients (10 men, 7 women; mean age 54.6 years) with clinically defined septic shock and 20 healthy volunteers (12 men, 8 women; mean age 52.2 years). MAIN RESULTS: Of the 17 patients with septic shock, 9 (53 %) survived. The systolic blood pressure increased significantly from 78+/-6 to 106+/-8 mm Hg 2 h after PMX-F treatment in patients with septic shock. Plasma endotoxin levels decreased significantly after treatment, from 40+/-6 to 12+/-4 pg/ml. The pretreatment plasma concentrations of EPO and IL-6 were significantly higher in the 8 nonsurviving patients with septic shock (EPO: 400+/-36 mlU/ml; IL-6: 6260+/-1180 pg/ml) than in the 9 surviving patients (EPO: 120+/-22 mlU/ml; IL-6: 680+/-138 pg/ml) and the 20 control subjects (EPO, 12+/-6 mlU/ml; IL-6, 8+/-2 pg/ml). Plasma concentrations of EPO and IL-6 in patients with septic shock decreased significantly after PMX-F treatment (EPO, nonsurviving: 320+/-28 mlU/ml, p < 0.05; survivors: 26+/-8 mlU/ ml, p < 0.001; IL-6, nonsurviving: 3860+/-840 pg/ml, p < 0.01; survivors: 84+/-20 pg/ml, p < 0.001). CONCLUSIONS: Plasma concentrations of EPO and IL-6 may be prognostic indicators in patients with septic shock: PMX-F treatment may be effective in reducing the plasma concentrations of EPO and IL-6 in patients with septic shock.     

Triple role of platelet-activating factor in eosinophil migration across monolayers of lung epithelial cells: eosinophil chemoattractant and priming agent and epithelial cell activator

Infiltration of eosinophils into the lung lumen is a hallmark of allergic asthmatic inflammation. To reach the lung lumen, eosinophils must migrate across the vascular endothelium, through the interstitial matrix, and across the lung epithelium. The regulation of this process is obscure. In this study, we investigated the migration of human eosinophils across confluent monolayers of either human lung H292 epithelial cells or primary human bronchial epithelial cells. Established eosinophil chemoattractants (IL-8, RANTES, platelet-activating factor (PAF), leukotriene B4, and complement fragment 5a (C5a)) or activation of the epithelial cells with IL-1beta induced little eosinophil transmigration (<7% in 2 h). In contrast, addition of PAF in combination with C5a induced extensive (>20%) transepithelial migration of unprimed and IL-5-primed eosinophils. Eosinophil migration assessed in a Boyden chamber assay, i.e., without an epithelial monolayer, was only slightly increased upon addition of PAF and C5a. Preincubation of eosinophils with the PAF receptor antagonist WEB 2086 only inhibited migration of unprimed eosinophils toward PAF and C5a, whereas preincubation of epithelial cells with WEB 2086 abolished migration of both IL-5-primed and unprimed eosinophils. This latter result indicated the presence of PAF receptors on epithelial cells. Indeed, addition of PAF to epithelial cells induced an increase in cytosolic free Ca2+, which was blocked by the PAF receptor antagonists WEB 2086 and TCV-309. Our results show that PAF induces permissive changes in epithelial cells, and that PAF acts as a chemoattractant and priming agent for the eosinophils.     

Interleukin-8 concentration predicts the neutrophil count in middle ear effusion

Interleukin-8 (IL-8), a potent neutrophilic chemoattractant and inflammatory cytokine, is present in middle ear effusions (MEEs) of children with otitis media and is thought to be responsible for the accumulation of neutrophils in MEEs. We hypothesized that IL-8 concentration predicts the total number and proportion of neutrophils in MEEs. IL-8 concentration and total and differential cell counts were measured in MEEs of children undergoing tympanostomy tube placement for otitis media. IL-8 was present in 80 (98%) of 82 effusions. The mean +/- SEM value for IL-8 was 7342 +/- 847 pg/mL. The mean +/- SEM count and percentage of neutrophils were 1.34 x 10(6) +/- 3.44 x 10(5) and 70.6 +/- 3.1%, respectively. IL-8 concentrations correlated positively with the total number (r = +0.30; P = 0.02) and percentage of neutrophils (r = +0.32; P = 0.01) in the effusion. Additionally, purulent effusions had greater IL-8 concentrations (P = 0.003) and greater neutrophil count (P = 0.03) than mucoid or serous effusions. We conclude that IL-8 is consistently present in MEEs of children and IL-8 concentration predicts the total number and proportion of neutrophils. Furthermore, IL-8 concentration and the total number of neutrophils correlate positively with the type of effusion. These results support the hypothesis that IL-8 recruits neutrophils to the middle ear in MEEs.     

Traumatic injury induces interleukin-6 production by human astrocytes

The brain is being evaluated as a de novo source of cytokines. Because recent evidence indicates that interleukin-6 (IL-6) may influence blood-brain barrier function and vascular permeability, we have sought to determine whether mechanical injury can directly induce in situ cerebral IL-6 production. Adult human astrocyte cultures were subjected to mechanical injury by the in vitro method of fluid percussion barotrauma, developed in our laboratory. Serial supernatant samples were collected for 8 h and evaluated for IL-6 activity using a proliferation assay employing the dependent B cell hybridoma cell line, B9. At optimum injury, the IL-6 level became significantly (P < 0.0001, analysis of variance) elevated from baseline 2 h after trauma and continued to increase over the observation period. Our study shows that following mechanical injury human astrocytes produce IL-6, which may contribute to post-traumatic cerebrovascular dysfunction. Elucidating the precise role of intracerebral cytokines is essential to our understanding of the mechanism responsible for post-traumatic cerebrovascular dysfunction.     

Synovial fluid interleukin-8 and neutrophil function in rheumatoid arthritis and seronegative polyarthritis

The relationships between synovial fluid (SF) interleukin-8 (IL-8) and neutrophil turnover as measured by cytidine deaminase (CD), and SF metabolites were studied in 28 patients, 16 with rheumatoid arthritis (RA; median age and disease duration 62 and 14 yr, respectively) and 12 with seronegative polyarthritis (SNP; median age and disease duration 32 and 5 yr, respectively). Knee SF samples were aspirated using indwelling cannulae following a period of rest for 1 h. SF IL-8 levels (measured by an ELISA) were significantly elevated in RA compared to SNP (median 2.35 vs 0.22 ng/ml, P < 0.001), as were median levels of CD (55.8 vs 8.11 U/ml, P < 0.01), lactic acid (29.6 vs 16.6 mg/dl, P < 0.001), glucose (57.9 vs 84.5 mg/dl, P < 0.05) and the lactate to glucose ratio (0.85 vs 0.19, P < 0.001). Measures of disease activity, C-reactive protein, plasma viscosity and articular index were also elevated in RA compared to SNP (P < 0.05). SF IL-8 levels correlated strongly with CD, lactate, glucose and the lactate to glucose ratio when both disease groups were considered together (P < 0.001). These parameters also showed some association with the measures of disease activity (P < 0.05). All these associations were less marked when the individual disease groups were analysed separately. These results suggest that factors responsible for neutrophil accumulation and priming (probably IL-8) are present in SF, and these coincide with products of their activation (CD). The degree of neutrophil turnover is linked to the anaerobic metabolism of the synovial cavity.     

Epidemiology of immediate and early trauma deaths at an urban Level I trauma center

The objective of this study is to identify and differentiate the injury patterns and causes of death among patients who died within the 1st hour and those in the period between 1 and 48 hours after hospital admission. Information was collected from the 1994 to 1996 trauma data base at an urban Level I trauma center. The records of 155 trauma patients who died within the 1st hour (immediate trauma death, ITD) and between 1 and 48 hours (early trauma death, ETD) were examined retrospectively. Total and constituent Injury Severity Score (ISS), Trauma Score (TS), and Glasgow Coma Score were analyzed. ITDs constituted 49 per cent of all deaths within 48 hours. Blunt mechanisms accounted for 37 per cent of ITDs and 40 per cent of ETDs (not significant), whereas penetrating trauma accounted for 59 per cent of ITDs and 56 per cent of ETDs (not significant). Exsanguination most commonly caused death among ITDs (54%) and head injury (51%) among ETDs (P < 0.01). Patients who died within the 1st hour had higher ISS (42.6 +/- 23.2, P < 0.03), lower TS (1.7 +/- 1.9, P < 0.0001), and lower Glasgow Coma Score (3.1 +/- 1.1, P < 0.0001) than those who died after the 1st hour. Patients with ITD had a significantly worse chest ISS than those with ETD (47.4 +/- 28.6 vs 19.0 +/- 19.1, P < 0.0001). We conclude that 1) ITD is caused primarily by exsanguination, whereas ETD is largely due to the sequelae of severe neurologic injury; 2) ITD has a significantly lower TS and higher ISS than ETD; and 3) thoracic injuries are more severe among patients with ITDs than among those with ETDs. The severity of thoracic injury among ITDs suggests that rapid surgical intervention is critical during the resuscitation of these severely injured patients.