BACKGROUND: Since the exact pathogenesis of sepsis-induced ARDS has not been elucidated, the mechanisms of enhanced neutrophilic respiratory burst were probed in endotoxin primed neutrophils associated with the roles of phospholipase A2 (PLA2), platelet activating factor (PAF) and apoptosis. METHODS: In isolated fresh human neutrophils, effects of the inhibition of PLA2 and PAF on the apoptosis were examined by the method of Annexin-FITC/dual PI flow cytometry. The roles of PLA2 and PAF on the neutrophilic respiratory burst were also examined by measuring oxidant generation in cytochrome-c reduction assay. Activities of the PLA2 and lysoPAF acetyltransferase (lysoPAF AT) of the neutrophils were determined to understand the effect of endotoxin on these enzymatic activities which may be related to the neutrophilic respiratory burst and apoptosis. In addition, the role roles of PLA2 and PAF in neutrophilic adhesion to bovine endothelial cells were examined in vitro by neutrophil adhesion assay. To investigate the effect of oxidants on pulmonary surfactant, cytochemical ultrastructural microscopy was performed. To inhibit PLA2 and PAF, non-specific PLA2 inhibitor mepacrine (100 nM) and WEB 2086 (100 nM) or ketotifen fumarate (10 kg/ml) were used respectively in all in vitro experimental sets. WEB 2086 is PAF receptor antagonist, and ketotifen fumarate is a lyso PAF AT inhibitor. RESULTS: The mapacrine treatment, provided after the endotoxin (ETX) treatment, resulted in increased apoptosis of neutrophils (p<0.001) while treatments of WEB 2086 and ketotifen did not. The inhibition of PLA2 and PAF decreased (p<0.001) production of oxidants from PMA-stimulated neutrophils. While endotoxin increased the PLA2 activity of neutrophils (p<0.01), mepacrine supressed (p<0.001) the activity, provided after treatment of ETX. The lyso PAF actyltransferase activity (lyso PAF AT) increased(p<0.01) after treatment of ETX. In contrast, mepacrine, WEB 2086 and ketotifen showed a tendency of decreasing the activity after treatment of ETX. The Treatment of ETX increased (p<0.001) neutrophil adhesion to endothelial cells, which was reversed by inhibition of PLA2 and PAF (p<0.001). The binding of oxidants to pulmonary surfactant was identified histologically. CONCLUSIONS: The enhanced neutrophilic respiratory burst by ETX plays a pivotal role in the pathogenesis of ARDS in term of oxidayive oxidative stress. Increased production of oxidants form neutrophils is mediated by the activations of PLA2 and lyso PAF AT.
Apoptosis* ; Endothelial Cells ; Flow Cytometry ; Humans ; Ketotifen ; Microscopy ; Neutrophils* ; Oxidants ; Oxidative Stress ; Phospholipases A2 ; Platelet Activating Factor ; Pulmonary Surfactants ; Quinacrine ; Respiratory Burst*

This study was aimed to elucidate the relationship between combinations of treadmill speed-grade and oxygen consumption(Vo2). Twenty athetic and 20 non-athletic male college students aged 19-24yr were employed to exercise on a treadmill using 4 speeds(4.02, 5.47, 6.76 and 8.05km/h) and 5 grades(0, 8, 12, 16 and 20%). A fixed speed was selected for each session with the grade increased every 3 min. The Vo2, heart rate, stride frequency and stride length were measured during the last min of each 3-min stage. Vo2increased linearly with increasing speed and grade showing significant multiple correlations in nonathletes(Vo2=3.64x+0.831y+0.031xy-7.03, R=0.98, P<0.01) and athletes(Vo2=3.48x+0.324y+0.112xy-5.74, R=0.99, P<0.01). Stride frequency and length tended to increase with increasing speed except for the transition from walking to runnig at 8.05Km/h at which the stride frequency ran up much higher with the stride length getting lower than at 6.76Km/h. Heart rate increased linearly with increasing Vo2. The rate of increase was higher during walking than during running. These results indicate that athletes have higher rate of increase in Vo2than nonathletes at near-maximal exercise and may be used as a guideline in predicting maximum oxygen comsumption and in prescribing exercise intensity.
Athletes* ; Heart Rate ; Humans ; Male ; Oxygen Consumption* ; Oxygen* ; Running ; Walking

BACKGROUND: For unknown reasons, the serum ferritin concentrations are higher in patients with acute lung injury. A pretreatment with aspirin reduces the acute lung injury in rats subjected severe hemorrhage, and increases the rate of ferritin synthesis in vitro. This study investigated the effect of aspirin on the serum ferritin changes in rats subjected to severe hemorrhage. METHODS: Hemorrhagic shock was induced by withdrawing blood (20 ml/kg of B.W.) through the femoral artery for 5 min. The rats were pretreated with aspirin (10 mg/kg, i.v.) 30 min before hemorrhage. RESULTS: The protein content and leukocyte count in the bronchoalveolar lavage fluid, lung tissue myeloperoxidase activities were significantly higher after hemorrhage. The aspirin pretreatment prevented these changes. The serum and lavage fluid ferritin concentrations were elevated higher after hemorrhage. These were also attenuated by the aspirin pretreatment. CONCLUSION: The changes in the serum and lung lavage ferritin level might be closely related to the severity of hemorrhage?induced acute lung injury. Therefore, the serum and lavage ferritin concentrations can be a useful biomarker for patients with precipitating conditions.
Acute Lung Injury* ; Animals ; Aspirin* ; Bronchoalveolar Lavage ; Bronchoalveolar Lavage Fluid ; Femoral Artery ; Ferritins ; Hemorrhage* ; Humans ; Leukocyte Count ; Lung ; Peroxidase ; Rats* ; Shock, Hemorrhagic ; Therapeutic Irrigation

BACKGROUND: For unknown reasons, the serum ferritin concentrations are higher in patients with acute lung injury. A pretreatment with aspirin reduces the acute lung injury in rats subjected severe hemorrhage, and increases the rate of ferritin synthesis in vitro. This study investigated the effect of aspirin on the serum ferritin changes in rats subjected to severe hemorrhage. METHODS: Hemorrhagic shock was induced by withdrawing blood (20 ml/kg of B.W.) through the femoral artery for 5 min. The rats were pretreated with aspirin (10 mg/kg, i.v.) 30 min before hemorrhage. RESULTS: The protein content and leukocyte count in the bronchoalveolar lavage fluid, lung tissue myeloperoxidase activities were significantly higher after hemorrhage. The aspirin pretreatment prevented these changes. The serum and lavage fluid ferritin concentrations were elevated higher after hemorrhage. These were also attenuated by the aspirin pretreatment. CONCLUSION: The changes in the serum and lung lavage ferritin level might be closely related to the severity of hemorrhage?induced acute lung injury. Therefore, the serum and lavage ferritin concentrations can be a useful biomarker for patients with precipitating conditions.
Acute Lung Injury* ; Animals ; Aspirin* ; Bronchoalveolar Lavage ; Bronchoalveolar Lavage Fluid ; Femoral Artery ; Ferritins ; Hemorrhage* ; Humans ; Leukocyte Count ; Lung ; Peroxidase ; Rats* ; Shock, Hemorrhagic ; Therapeutic Irrigation

Intestinal ischemia/reperfusion (I/R) is one of common causes of acute lung injury (ALI). Early and accurate diagnosis of patients who are like to develop serious acute respiratory distress syndrome (ARDS) would give a therapeutic advantage. Ferritin and heme oxygenase-1 (HO-1) are increased by oxidative stress and are potential candidates as a predictive biomarker of ARDS. However, the mechanisms responsible for the increases of ferritin and HO-1, and their relationship to ALI, are unclear. In order to elucidate the interactions between ferritin and HO-1, we studied the changes in ferritin and HO-1 levels in serum and bronchoalveolar lavage (BAL) fluid after intestinal I/R injury in rats. Leukocyte number and protein contents in BAL fluid were elevated following I/R, and the increases were attenuated by mepacrine pretreatment. Both serum ferritin and HO-1 concentrations were progressively elevated throughout the 3 h observation period. Mepacrine pretreatment attenuated the increase of serum and BAL fluid ferritin concentrations, but did not suppress the increase of serum HO-1. Moreover, BAL fluid HO-1 levels did not change after I/R or after mepacrine pretreated I/R compared with sham rats. Unlike ferritin, HO-1 levels are not exactly matched with the ALI. Therefore, there might be a different mechanism between the changes of ferritin and HO-1 in intestinal I/R-induced ALI model.
Acute Lung Injury ; Animals ; Bronchoalveolar Lavage ; Ferritins ; Heme ; Heme Oxygenase-1 ; Humans ; Imidazoles ; Leukocyte Count ; Lung ; Lung Injury ; Nitro Compounds ; Oxidative Stress ; Quinacrine ; Rats ; Respiratory Distress Syndrome, Adult ; Salicylamides

No abstract available.
Angiotensin II* ; Angiotensins* ; Animals ; Hemorrhage* ; Rats*

Serum ferritin levels are increased in subjects at-risk for or with acute lung injury (ALI), and there are observations to suggest that increases in serum ferritin levels may help predict the development of ALI in at-risk individuals. To deepen our understanding of increases of serum ferritin and their relationship to the development of ALI, we measured serum ferritin levels before and after intestinal ischemia/reperfusion (I/R) injury in rats, and found that serum ferritin levels increased significantly following I/R. Increases in serum and lavage ferritin levels paralleled increases in lung inflammation (lavage leukocyte numbers and tissue myeloperoxidase activities) and lung leak (lavage protein levels). In contrast, pre-treatment of rats with mepacrine (60 mg/kg, i.p.), a phospholipase A2 inhibitor, attenuated not only I/R-induced serum and lavage ferritin increases, but also the development of ALI. These findings indicate that, besides of human subjects with ALI, serum ferritin levels increase early on also in an animal model of ALI. Therefore, serum and lavage ferritin can be a candidate for early biomarker of ALI.
Acute Lung Injury* ; Animals ; Ferritins* ; Humans ; Leukocyte Count ; Lung ; Models, Animal ; Peroxidase ; Phospholipases A2 ; Pneumonia ; Quinacrine ; Rats ; Therapeutic Irrigation

BACKGROUND: The underlying pathogenesis of fat embolism-induced acute lung injury (ALI) has not been elucidated. In the present study, the pathogenesis of fat embolism-induced ALI was probed in association with neutrophilic oxidative stress in oleic acid (OA)-induced ALI of S-D rats. METHODS: OA was injected intravenously to provoke ALI in experimental rats. Five hours later, indices of ALI were measured to confirm the role of the neutrophilic respiratory burst. The effect of an inhibition of phospholipase A2 (PLA2) was also evaluated. RESULTS: The accumulation of neutrophils in the lung due to OA caused increased neutrophilic oxidative stress in lung, which was ameliorated by mepacrine. What were the results from inhibition of PLA2. CONCLUSION: Excess neutrophilic oxidative stress contributes to OA-induced ALI, which is lessened by the inhibition of PLA2.
Acute Lung Injury ; Animals ; Embolism, Fat ; Lung ; Neutrophils ; Oleic Acid ; Oxidative Stress ; Phospholipases A2 ; Quinacrine ; Rats ; Respiratory Burst

BACKGROUND: Hemorrhagic shock and trauma are two of the most common causes of acute lung injury. The activation of cyclooxygenase is one of the important causes of acute lung injury. This study investigated the effect of aspirin, a well-known cyclooxygenase inhibitor, on severe hemorrhage-induced acute lung injury in rats. METHODS: The hemorrhagic shock was induced by withdrawing blood; 20ml/kg of B.W., through the femoral artery in 5 min. The mean arterial pressure was recorded through the femoral artery on a polygraph. RESULTS: In the present investigation, the lung tissue myeloperoxidase activity, protein contents and leukocyte counts, in bronchoalveolar lavage fluid, increased significantly 2 and 24 h after the hemorrhage induction. Although the decreased mean arterial pressure spontaneously recovered, acute lung injury occurred after severe hemorrhage. These changes were effectively prevented by a single intravenous injection of aspirin (10 mg/kg of B.W.) 30 min before the hemorrhage. CONCLUSION: These results suggest that severe hemorrhage-induced acute lung injury is mediated, in part, by the activation of cyclooxygenase. Furthermore, pretreatment of aspirin in acute lung injury-prone patients, or prophylactic treatment of aspirin to the patients with precipitating conditions, could be helpful in the prevention of acute lung injury.
Acute Lung Injury* ; Animals ; Arterial Pressure ; Aspirin* ; Bronchoalveolar Lavage Fluid ; Femoral Artery ; Hemorrhage* ; Humans ; Injections, Intravenous ; Leukocyte Count ; Lung ; Peroxidase ; Prostaglandin-Endoperoxide Synthases ; Rats* ; Shock, Hemorrhagic

Background: In order to elucidate one of the pathogenic mechanisms of ARDS associated with pulmonary surfactant and oxidant injury, acute lung injury was induced by N-nitroso- N-methylurethane (NNNMU). In this model, the role of phospholipase A2 (PLA2), surfactant, gamma glutamyl transferase (GGT) and morphology were investigated to delineate one of the pathogenic mechanisms of ARDS by inhibition of PLA2 with high dose of dexamethasone. Method: Acute lung injury was induced in Sprague-Dawley rats by NNNMU which is known to induce acute lung injury in experimental animals. To know the function of the alveolar type II cells, GGT activity in the lung and bronchoalveolar lavage was measured. Surfactant phospholipid was measured also. PLA2 activity was measured to know the role of PLA2 in ARDS. Morphological study was performed to know the effect of PLA2 inhibition on the ultrastructure of the lung by high dose of dexamethasone. Results: Six days after NNNMU treatment (4 mg/kg), conspicuous pulmonary edema was induced and the secretion of pulmonary surfactant was decreased significantly. In the acutely injured rats' lung massive infiltration of leukocytes was observed. At the same time rats given NNNMU had increased PLA2 and GGT activity tremendously. Morphological study revealed bizarre shaped alveolar type II cells and hypertrophied lamellar bodies in the cytoplasm of the alveolar type II cells. But after dexamethasone treatment (20 mg/kg, for six days) in NNNMU-treated rats, these changes were diminished i.e. there were decrease of pulmonary edema and increase of surfactant secretion from alveolar type II cells. Rats given dexamethasone and NNNMU had decreased PLA2 and GGT activity in comparison to NNNMU induced ARDS rats. Conclusion: Inhibition of PLA2 by high dose of dexamethasone decreased pathological findings caused by infiltration of leukocytes and respiratory burst. Based on these experimental results, it is suggested that an activation of PLA2 is the one of the major factors to evoke the acute lung injury in NNNMU-induced ARDS rats.
Acute Lung Injury ; Animals ; Bronchoalveolar Lavage ; Cytoplasm ; Dexamethasone* ; Leukocytes ; Lung* ; Phospholipases A2 ; Pulmonary Edema ; Pulmonary Surfactants ; Rats* ; Rats, Sprague-Dawley ; Respiratory Burst ; Transferases