摘要:

ABSTRACT—Activation of the nuclear regulatory factor NF‐&kgr;B occurs in the lungs of patients with the acute respiratory distress syndrome (ARDS) and may contribute to the increased expression of immunoregulatory cytokines and other proinflammatory mediators in this setting. Because of the important role that NF‐&kgr;B activation appears to play in the development of acute lung injury, we examined cytoplasmic and nuclear NF‐&kgr;B counterregulatory mechanisms, involving l&kgr;B proteins, in alveolar macrophages obtained from 7 control patients without lung injury and 11 patients with established ARDS. Cytoplasmic levels of the NF‐&kgr;B subunits p50, p65, and c‐Rel were significantly decreased in alveolar macrophages from patients with ARDS, consistent with enhanced migration of liberated NF‐&kgr;B dimers from the cytoplasm to the nucleus. Cytoplasmic and nuclear levels of l&kgr;B&agr; were not significantly altered in alveolar macrophages from patients with established ARDS, compared with controls. In contrast, nuclear levels of Bcl‐3 were significantly decreased in patients with ARDS compared with controls (P= 0.02). No l&kgr;B&ggr;, l&kgr;B&bgr;, or p105 proteins were detected in the cytoplasm of alveolar macrophages from control patients or patients with ARDS. The presence of activated NF‐&kgr;B in alveolar macrophages from patients with established ARDS implies the presence of an ongoing stimulus for NF‐&kgr;B activation. In this setting, appropriate counterregulatory mechanisms to normalize nuclear levels of NF‐&kgr;B and to suppress NF‐&kgr;B‐mediated transcription, such as increased cytoplasmic and nuclear l&kgr;B&agr; levels or decreased Bcl‐3 levels, appeared to be induced. Nevertheless, even though counterregulatory mechanisms to NF‐&kgr;B activation are activated in lung macrophages of patients with ARDS, NF‐&kgr;B remains activated. These results suggest that fundamental abnormalities in transcriptional mechanisms involving NF‐&kgr;B and important in the inflammatory response occur in the lungs of patients with ARDS.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—Altered intracellular Ca2+concentration is a pivotal regulatory mechanism of leukocyte function. Since polymorphonuclear neutrophils (PMN) are involved in traumatic organ dysfunction, we prospectively investigated Ca2+regulation and function of circulating PMN multiple trauma patients (Group A: ISS < 27; Group B: ISS ≥ 27). Circulating PMN were isolated during 12 days, followed by determination of formyl‐methionyl‐leucyl‐phenylalanine (fMLP)‐induced PMN‐superoxide production (PMN‐SOP) by SOD‐inhibitable ferricytochrome C reduction, and PMN cytosolic Ca2+concentration ([Ca2+]i) by fluorescent fura2/AM (340/380 ratio). PMN‐SOP was significantly higher in Group B (mean ISS: 39.9 ± 2; n = 21) at day of admission than in controls and Group A (mean ISS: 18.2 ± 1; n = 22) (P< 0.05). In Group B, the significant rise of basal [Ca2+]ibetween Day 2 and Day 4 was associated with significant lower PMN‐SOP during that period (P< 0.05). The fMLP‐induced [Ca2+]iresponse was supranormal in both groups. PMN‐elastase concentrations were substantially higher in Group B compared with Group A until Day 4. Circulating IL‐6, IL‐8, and soluble TNF‐receptor (55 kD) were significantly increased in Group B compared with Group A at the day of trauma (P< 0.05). Severe trauma is characterized by a biphasic pattern of neutrophil priming characterized by early increase and secondary suppression. The association of depressed neutrophil superoxide production (deactivation) and elevated basal [Ca2+]isuggests Ca2+‐mediated disturbance of neutrophil NADPH‐oxidase metabolism.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—The physiological, hemostatic, and immunological responses of 12 chronically instrumented conscious baboons with sepsis due toEscherichia coliperitonitis were compared with that of similarly instrumented controls. Chronic indwelling cannulae were placed in the aorta and pulmonary artery to monitor pressure, cardiac output, and obtain blood samples. At t = 0 a sterile orE. coli‐laden fibrin clot containing 1.9‐6.7 × 1011CFU/kg was introduced into the peritoneal cavity. The control animals were group 1 (n = 3). The animals with peritonitis were divided into three groups depending on their clinical response. Group 2 animals (n = 3) were clinically well at the time of sacrifice (day 14), group 3 (n = 4) survived but were obviously sick on day 14, and group 4 (n = 5) died of sepsis. Implantation of a sterile fibrin clot was well tolerated with little hemodynamic change and a transient minimal inflammatory response in group 1. Implantation of anE. coli‐containing clot elicited a hyperdynamic cardiovascular response and evoked a marked inflammatory reaction and a disseminated intravascular coagulopathy. Five of 12 (42%)E. colianimals died from sepsis. In general, the physiological, hemostatic, and immunological disturbances tended to be greatest in these animals. Autopsy revealed residual peritoneal inflammation and varying degrees of inflammation in the lungs, adrenal, spleen, liver, and kidneys in all the animals that receivedE. coliwith the inflammatory infiltrate increasing in severity from group 2 through group 4. Tissue necrosis was observed only in the latter group. We conclude that the cardiovascular, hemostatic, and immunological responses of baboons with sepsis due toE. coliperitonitis exhibit a variable course that resembles the clinical manifestations of gram‐negative sepsis in humans.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—Sepsis remains a serious clinical problem despite intense efforts to improve survival. Experimental animal models of sepsis have responded dramatically to immunotherapy blocking the activity of cytokines. Despite these preclinical successes, human clinical trials have not demonstrated any improvement in survival. We directly compared the mortality, morbidity, and immunopathology in two models of sepsis, one due to lipopolysaccharide (LPS) and the other to cecal ligation and puncture (CLP). BALB/c mice were injected intraperitoneally with 250 &mgr;g of LPS or subjected to CLP with an 18‐gauge needle. Both models yielded similar mortality (> 85%) and morbidity. Additionally, neutropenia and lymphopenia developed in both groups. Plasma and peritoneal levels of cytokines (TNF, IL‐1, IL‐6, and the chemokines KC and MIP‐2) were measured at 1.5, 4, and 8 h after challenge. LPS induced substantially higher levels of cytokines in both compartments with peak levels between 1.5 and 4 h that began to decline at 8 h. In contrast, cytokine levels in the CLP model were continuing to increase at the 8 h‐time point and often exceeded the LPS‐induced values at this time. Our data demonstrate that the LPS and CLP models have similar mortality but significant differences in the kinetics and magnitude of cytokine production. Immunotherapy for sepsis based on cytokine production after LPS challenge is misdirected because the LPS model does not accurately reproduce the cytokine profile of sepsis.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—Previously we found the structural integrity of the aortic endothelium was maintained after the administration of endotoxin in type 1 interleukin‐1 (IL‐1) receptor knockout mice. In this study, we investigated further the integrity of pulmonary vascular endothelium, airway epithelial, pulmonary microvasculature, and neutrophil infiltration into the microvasculature and respiratory air spaces. Adult male C57BL/129J wild‐type mice and C57BL/129J knockout mice possessing a homozygous deletion of the type 1 IL‐1 receptor received the following intraperitoneal injections; 1)Escherichia coliendotoxin (ENDT) (10 mg/kg), 2) ENDT (2 mg/kg given for 4 days), or (3) saline vehicle. Wild‐type and knockout control animals receiving saline vehicle showed normal endothelial and epithelial ultrastructure with intact membranes. Pulmonary endothelial cell damage was found only in wild‐type mice given a single 10 mg/kg endotoxin dose. Airway epithelial damage was found only in wild‐type mice given a repetitive dose of endotoxin (2 mg/kg for 4 days). Neutrophil infiltration increased only in mice given a single dose of endotoxin (10 mg/kg) with the wild‐type increasing by 32% and the knockouts by 6% compared with the saline control for that group respectively. Serum IL‐6 and nitric oxide (indicators of septic shock severity and lethality) significantly increased only in the mice given 10 mg/kg of endotoxin. The maintenance of pulmonary endothelial and epithelial cell integrity and the decrease of neutrophil infiltration in the IL‐1 knockout mice suggest that IL‐1 contributes significantly to the severity of endotoxin‐induced sepsis.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—Expression of the inducible isoform of nitric oxide (NO) synthase, and the formation of peroxynitrite from NO and superoxide are responsible for some of the pathophysiological alterations seen during reperfusion injury and in various inflammatory conditions. Some of the effects of peroxynitrite are related to DNA single‐strand breakage, and activation of poly (ADP‐ribose) synthetase. Here we investigated the effect of nicaraven (2(R,S)‐1,2‐bis(nicotinamido)propane), a known hydroxyl radical scavenger compound and neuroprotective agent, on several NO‐ and peroxynitrite related pathwaysin vitro, and in shock and inflammationin vivo.Nicaraven, at 10 &mgr;M‐10 mM, failed to inhibit the peroxynitrite‐induced oxidation of dihydrorhodamine 123, indicating that the agent does not act as a scavenger of peroxynitrite. In RAW murine macrophages stimulated with peroxynitrite, nicaraven caused a dose‐dependent, slight inhibition of poly (ADP‐ribose) synthetase activation, possibly due to a direct inhibitory effect on the catalytic activity of poly (ADP‐ribose) synthetase. Nicaraven partially protected against the peroxynitrite‐induced suppression of mitochondrial respiration in RAW macrophages and caused a slight, dose‐dependent inhibition of nitrite production in RAW macrophages stimulated with bacterial lipopolysaccharide. We next investigated the effect of nicaraven treatment in a variety of models of inflammation and reperfusion injury. Nicaraven (at 10‐100 &mgr;g/paw) exerted significant protective effects in the carrageenan‐induced paw edema model and (at 100 mg/kg i.v.) reduced neutrophil infiltration and histological damage in splanchnic artery occlusionreperfusion injury. However, nicaraven failed to alter the course of hemorrhagic and endotoxic shock and arthritis in rodent models. The current data indicate the limited role of hydroxyl radicals in the pathogenesis of the inflammatory conditions tested.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—The expression of inducible nitric oxide synthase (iNOS) is increased in the intestine and results in mucosal damage after endotoxin challenge. Although the oral administration of total parenteral nutrition (TPN) solution promotes bacterial translocation (BT) and increases the intestinal permeability, the role of NO in the nutrition‐induced loss of mucosal barrier function remains unclear. The distribution of fluorescein isothiocyanate‐dextran (FITC‐dextran, 4400) across the lumen of small intestine in rat was examined to investigate the role of NOS activity on the intestinal permeability under oral TPN feeding. Fifty‐one rats were randomly divided into 4 groups. Group I (control group) was fed with rat chow, group II received TPN solution orally. Groups III and IV received TPN solution supplemented with NOS inhibitors. On day 9, FITC‐dextran was injected into the intestinal lumen. After 30 min, blood samples were taken from portal vein and analyzed for plasma FITC‐dextran level by fluorescence spectrophotometry. Samples of small intestine were frozen and sectioned in a cryostat for morphological and NOS histochemical studies, Homogenates of small intestine were used for NOS activity measurement. The plasma level of FITC‐dextran showed a significant increase (P< 0.05) in rats fed with oral TPN compared with the control ones. Supplement with NOS inhibitors significantly decreased the intestinal permeability in groups III and IV compared with group II. Similarly, the total NOS activities showed a significant 2‐fold increase (P< 0.05) in group II, and NOS inhibitors decreased the elevated NOS activity. These data suggest that oral TPN feeding for 9 days leads to an increase in permeability to dextran and the total NOS activity of small intestine, and both induction of the intestinal permeability and NOS activity were inhibited by treatment with NOS inhibitors. Addition of S‐methylisothiourea (SMT), an iNOS selective inhibitor, profoundly inhibited 66% of the induced iNOS activity (P< 0.05) and reduced 74% of the diet‐induced increase in intestinal permeability (P< 0.05) in group II. The induced permeability change in rats receiving oral TPN is mainly due to the activity of intestinal mucosal iNOS. The induction of iNOS is an important mediator for intestinal barrier dysfunction. Administration of SMT, which specifically decreases iNOS activity, is useful in the prevention of diet‐induced barrier failure.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—Leukocyte‐endothelial cell interactions play an important role in mediating organ dysfunctions observed after hemorrhagic shock. P‐selectin is the first endothelial cell adhesion molecule to be upregulated after an ischemic insult. The objective of this study was to define kinetics of P‐selectin expression in different regional vascular beds of mice exposed to hemorrhagic shock.In‐vivoP‐selectin expressions were determined using dual radiolabeled monoclonal antibody technique in lungs, heart, liver, kidneys, intestinal mesentery, stomach, small bowel, and colon 0.5, 1, 2, 5, 10, and 24 h after resuscitation of 40 mmHg hemorrhagic shock. In another group, P‐selectin expression was determined in same organs 5 h after resuscitation of 30 mmHg hemorrhagic shock. Hemorrhagic shock of 40 mmHg caused significant upregulation of P‐selectin in lungs and liver at 30 min after resuscitation (P< 0.001). There was a second and more pronounced upregulation of P‐selectin in lungs and liver at 5 h after resuscitation (P< 0.001). In heart, intestinal mesentery, stomach, small bowel, and colon, P‐selectin was not upregulated until 5 h after resuscitation from 40 mmHg hemorrhagic shock (P< 0.001). While hemorrhagic shock of 40 mmHg did not cause P‐selectin upregulation in kidneys, hemorrhage to 30 mmHg did elicit a significant increase at 5 h after resuscitation (P< 0.001). We conclude that P‐selectin is upregulated after resuscitation of hemorrhagic shock in lungs, liver, heart, stomach, and intestines. P‐selectin upregulation in kidneys only takes place after more severe hemorrhagic shock.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—Endotoxemia is associated with increased sympathetic nerve activity and depletion of norepinephrine (NE) and epinephrine (EPI) contents in the adrenal gland and in sympathetically innervated tissues. Endotoxin (bacterial lipopolysacchride [LPS]) causes an increased production of nitric oxide (NO) by inducing nitric oxide synthase (iNOS) expression in various tissues. This increased production of NO contributes significantly to the hypotension associated with endotoxemia. At high concentrations, NO also can act as a neurotoxin. In this study we tested the hypothesis that increased production of NO is involved in depletion of catecholamine content in various tissues from rats treated with a nonlethal dose of LPS. Catecholamine content was measured by high‐performance liquid chromatography with electrochemical detection (HPLC‐EC) and NOS activity was measured by the3H‐l‐arginine to3H‐I‐citrulline conversion method. The NE content was decreased in rat adrenal gland, lung, spleen, tail artery, and aorta after LPS. The maximal decrease was at 24 h and returned to control levels at 6 days (144 h). There was no depletion of the NE content in the heart. The EPI content in the adrenal gland was greatly depleted (91%) from 12 to 72 h after LPS. LPS increased the NOS activity in all tissues examined. The time course for NOS activity showed an increase at 3 h, a further increase at 6 h, and a return to control level at 48 h after LPS. The increase in NOS activity occurred before maximal catecholamine depletion. Aminoguanidine, a relatively selective iNOS inhibitor, completely prevented NE depletion in all tissues and partially prevented adrenal EPI depletion induced by LPS. These results are consistent with the hypothesis that LPS‐induced production of NO plays a role in depletion of tissue NE and EPI.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ABSTRACT—In the setting of rapidly exsanguinating hemorrhage, resuscitation with intravenous (i.v.) crystalloid solution may not sustain survival before availability of allogenic blood transfusion and surgery. This study tested the hypothesis that bovine hemoglobin‐based oxygen carrier, HBOC‐201, would improve resuscitation and extend early survival from exsanguinating hemorrhage. This study simulated the prehospital scenario of rapidly exsanguinating hemorrhage with prolonged prehospital time and lack of blood availability. Severe hemorrhagic shock was induced in swine by using multiple liver lacerations. At 9 min after the onset of bleeding, swine were randomized to receive approximately 10 mL/kg/min of i.v. lactated Ringer's solution (n = 10) or HBOC‐201 (n = 7) to achieve a mean aortic pressure (MAP) of 60 mmHg. Thereafter, infusion rate was adjusted to maintain MAP at 60 mmHg for up to 2 h. All animals were initially successfully resuscitated. The results showed 2‐h survival was 1 of 10 with lactated Ringer's and 7 of 7 with HBOC‐201 (P= 0.0004). Nine lactated Ringer's swine had cardiovascular collapse at 36 ± 10 min. Lactate at 30 min was 18 ± 3 mmol/L with lactated Ringer's and 12 ± 2 mmol/L with HBOC‐201 (P< 0.05). Hematocrit was <1% in 9 of 10 lactated Ringer's and 6 of 7 HBOC‐201 animals. These data indicate that HBOC‐201 improved early survival and stabilized hemodynamic and metabolic parameters vs. lactated Ringer's in this swine model of liver injury with uncontrolled, lethal hemorrhage that simulates the prehospital care environment where allogenic blood is unavailable.

ISSN:1073-2322    

出版商:OVID    

年代:2000

数据来源: OVID