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J Pugin

Publications and source records attributed to J Pugin.

47 records · Page 3Linked to original sources
PubMed1993

A critical role for monocytes and CD14 in endotoxin-induced endothelial cell activation.

Vascular endothelium activated by endotoxin (lipopolysaccharide [LPS]) and cytokines plays an important role in organ inflammation and blood leukocyte recruitment observed during sepsis. Endothelial cells can be activated by LPS directly, after its interaction with LPS-binding protein and soluble CD14 in plasma. LPS-LPS-binding protein complexes in blood also interact with monocytes and neutrophils bearing glycosyl-phosphatidylinositol (GPI) anchored membrane CD14 (mCD14), promoting the release of cytokines such as tumor necrosis factor and interleukin 1 (IL-1). These molecules, in turn, have the capacity to activate endothelial cells providing an indirect pathway for LPS-dependent endothelial cell activation. In this work, we address the relative importance of the direct and the indirect pathway of in vitro LPS-induced human umbilical vein endothelial cell (HUVEC) activation. Substituting whole blood for plasma resulted in a 1,000-fold enhancement of HUVEC sensitivity to LPS. Both blood- and plasma-dependent enhanced activation of HUVEC were blocked with an anti-CD14 monoclonal antibody. Blood from patients with paroxysmal nocturnal hemoglobinuria, whose cells lack mCD14 and other GPI anchored proteins, was unable to enhance LPS activation of HUVEC above the level observed with plasma alone. IL-10, an inhibitor of monocyte release of cytokines, decreased the blood-dependent enhancement of HUVEC activation by LPS. Blood adapted to small doses of LPS was also less efficient than nonadapted blood in producing this enhancement. Addition of purified mononuclear cells to HUVEC or the transfer of plasma from whole blood incubated with LPS to HUVEC, duplicated the enhancement effect observed when whole blood was incubated with HUVEC. Taken together, these data suggest that the indirect pathway of LPS activation of endothelial cell is mediated by monocytes and mCD14 through the secretion of a soluble mediator(s). The indirect pathway is far more efficient than the direct, plasma-dependent pathway.

Antigens, CD↗
PubMed1993

Lipopolysaccharide activation of human endothelial and epithelial cells is mediated by lipopolysaccharide-binding protein and soluble CD14.

Myeloid cell activation by lipopolysaccharides (LPS) involves two proteins, plasma LPS-binding protein (LBP) and cell-membrane CD14. Cell membrane CD14, anchored by a glycerophosphatidylinositol tail, is the cellular receptor for LPS-LBP complexes. Another form of CD14, without the lipid tail, circulates as a soluble plasma protein. In this work we show that soluble CD14 (sCD14) is required for activation of endothelial and epithelial cells by LPS. We propose that LPS-LBP complexes transfer LPS to sCD14, and the LPS-sCD14 complexes then bind to a cellular receptor. Support for this pathway comes from experiments in which LBP and CD14 in normal human serum are blocked by specific antibodies, experiments in which serum is replaced by purified LBP and sCD14, and experiments in which specific binding of [3H]LPS to epithelial cells is quantitated.

Acute-Phase Proteins↗
PubMed1992

Diagnostic bronchoalveolar lavage in patients with pneumonia produces sepsis-like systemic effects.

Fever following fiberoptic bronchoscopy occurs in 10-25% of the patients and its origin is not well understood. We prospectively examined changes in body temperature (T degrees), mean systemic arterial pressure (MAP) and oxygenation after 2 bronchoalveolar lavages (BAL, bronchoscopic and non-bronchoscopic) for 34 procedures in 25 intubated patients. In patients with pneumonia (11 investigations) we observed a rise in T degrees 3 h after bronchoscopic and non-bronchoscopic BAL, p less than 0.0001, a decrease in MAP, p = 0.008 and arterial oxygenation, p = 0.002. Of patients with pneumonia 73% had a rise in T degrees of more than 1 degrees C compared with only 17% of those without pneumonia (p = 0.005). Patients without pneumonia (23 procedures) had no significant changes in T degrees, MAP and arterial oxygenation following the 2 BAL procedures. Changes in T degrees correlated significantly with those in MAP, and with the level of endotoxin in bronchoscopic BAL fluid. These findings suggest that BAL in patients with pneumonia may cause intravascular translocation of toxins or mediators producing pyrogenic and hypotensive effects.

Adolescent↗
PubMed1992

Rapid diagnosis of gram negative pneumonia by assay of endotoxin in bronchoalveolar lavage fluid.

BACKGROUND: Diagnosis of ventilator associated pneumonia can be made by quantitative cultures of bronchoalveolar lavage fluid or of protected specimen brushings, though cultures require 24-48 hours to provide results. In 80% of cases aerobic Gram negative bacteria are the cause. METHODS: A rapid diagnostic method of assessing the endotoxin content of lavage fluid by Limulus assay is described. Forty samples of lavage fluid were obtained from patients with multiple trauma requiring mechanical ventilation for a prolonged period. Pneumonia was diagnosed on the basis of clinical, radiological, and bacteriological findings, including quantitative cultures of lavage fluid. RESULTS: A relation was observed between the concentration of endotoxin in lavage fluid and the quantity of Gram negative bacteria. The median endotoxin content of lavage fluid in Gram negative bacterial pneumonia was 15 endotoxin units (EU)/ml; the range observed in individual patients was 6 to > 150 EU/ml. In patients with pneumonia due to Gram positive cocci and in non-infected patients the median endotoxin level was 0.17 (range < or = 0.06 to 2) EU/ml. An endotoxin level greater than or equal to 6 EU/ml distinguished patients with Gram negative bacterial pneumonia from colonised patients and from those with pneumonia due to Gram positive cocci. CONCLUSION: The measurement of endotoxin in lavage fluid is a rapid (less than two hours) and accurate diagnostic method. It should allow specific and early treatment of Gram negative bacterial pneumonia.

Bronchoalveolar Lavage Fluid↗
PubMed1992

Participation of lipopolysaccharide-binding protein in lipopolysaccharide-dependent macrophage activation.

Only recently has the mechanism for lipopolysaccharide (LPS) recognition by macrophages been elucidated. In contrast to many ligand receptor interactions, the interaction of LPS with its receptor, CD14, on myeloid cells is greatly enhanced by prior complexation of LPS with LPS-binding protein (LBP), a recently discovered plasma glycoprotein. LBP is found in normal serum or plasma in the 5 to 10 micrograms/ml range. In plasma, it reacts rapidly but transiently with LPS. LPS-LBP complexes then react with CD14 bearing cells. Blocking CD14 with monoclonal antibodies or removal of LBP from plasma blocks the ability of the cells to react with LPS-LBP complexes and also blocks release of cytokines and other mediators from the cells. In the normal lung, bronchoalveolar lavage fluid contains low levels of LBP. However, during acute lung injury, LBP levels may rise by transudation and enhance activation of alveolar macrophages to release injurious mediators. Description of this pathway for LPS recognition by macrophages and other leukocytes offers the possibility of developing new reagents to block LPS recognition and prevent the development of endotoxemia.

Acute-Phase Proteins↗
PubMed1991

[ The intestine-liver-lung axis in septic syndrome].

Abacteremic sepsis is frequent in intensive care units, and is closely associated with the development of adult respiratory distress syndrome (ARDS) and multiple systems organ failure (MSOF). It carries a high mortality. The gut is thought to be the "motor" of such septic states and the first step of a "gut-liver-lung axis". Shock of any type or sepsis can by themselves lead to increased permeability of the intestinal mucosal barrier. This, in turn, may promote bacterial translocation, i.e. the passage of bacteria or bacterial products such as endotoxin from the lumen of the gut into the portal bloodstream. When such products reach the liver, activation of Küpffer cells occurs, resulting in the secretion of pro-inflammatory and hypotensive mediators. The latter are mainly the tumor necrosis factor-alpha and interleukins-1 and -6. These substances trigger many biologic cascades, and may explain the development of abacteremic septic states and MSOF. The mediators cause binding of polymorphonuclear neutrophils to pulmonary endothelial cells, and their degranulation. In addition, they activate local and systemic coagulation mechanisms. This explains the morphological changes observed in early sepsis-induced ARDS, i.e. pulmonary edema, vascular thrombosis and hemorrhages. Studies are currently in progress in an attempt to limit bacterial and endotoxin translocation and the action of the mediators.

Bacterial Physiological Phenomena↗
PubMed1991

Diagnosis of ventilator-associated pneumonia by bacteriologic analysis of bronchoscopic and nonbronchoscopic "blind" bronchoalveolar lavage fluid.

Substantial efforts have been devoted to improving the means for early and accurate diagnosis of ventilator-associated (VA) pneumonia in intensive care unit (ICU) patients because of its high incidence and mortality. A good diagnostic yield has been reported from quantitative cultures of bronchoalveolar lavage (BAL) fluid or a protected specimen brush, both obtained by fiberoptic bronchoscopy. As bronchoscopy requires specific skills and is costly, we evaluated a simpler method to obtain BAL fluid, that is, by a catheter introduced blindly into the bronchial tree. Quantitative cultures from bronchoscopically sampled BAL (B-BAL) and blindly nonbronchoscopically collected BAL (NB-BAL) were assessed for sensitivity, specificity, and predictive value for the diagnosis of VA pneumonia. A total of 40 pairs of samples were examined in 28 patients requiring prolonged mechanical ventilation and presenting a high risk of developing pneumonia. For comparison with bacteriologic data we defined a clinical score for pneumonia ranging from zero to 12 using the following variables: body temperature, leukocyte count, volume and character of tracheal secretions, arterial oxygenation, chest X-ray, Gram stain, and culture of tracheal aspirate. To quantify the bacteria in BAL the bacterial index (BI) was used, defined as the sum of the logarithm of the number of bacteria cultured per milliliter of BAL fluid. A good correlation between clinical score and quantitative bacteriology was observed (r = 0.84 for B-BAL and 0.76 for NB-BAL; p less than 0.0001). Similar to studies in baboons, patients with pulmonary infection could be distinguished by a BI greater than or equal to 5 with a sensitivity of 93% and a specificity of 100% (B-BAL).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[The diagnosis of pneumonia in the ventilated patient].

The diagnosis of ventilator-associated pneumonia is difficult to confirm because the usual clinical criteria lack predictive value. Risk factors evaluated recently serve to assess subgroups of exposed patients. Bronchoscopic bronchoalveolar lavage (BAL) or protected specimen brush, together with quantitative bacteriology, are the present method of choice for diagnosis of nosocomial pneumonia during mechanical ventilation. Nonbronchoscopic "blind" BAL catheters provide new, attractive, accurate and easy sampling techniques. This could become the technique of choice in the future. Efforts are needed to standardize diagnostic criteria, in order to allow comparisons between groups of patients or clinical trials for prevention or treatment of ventilator-associated pneumonia.

Bacteriological Techniques↗
PubMedDate not supplied

Procalcitonin is not an accurate marker of spontaneous bacterial peritonitis in patients with cirrhosis.

BACKGROUND/AIMS: The clinical features of peritonitis are usually absent in cirrhotic patients with an ascitic fluid infection, raising the interest for specific biological markers of inflammation. METHODOLOGY: We prospectively measured the plasma and ascitic fluid levels of procalcitonin, an innovative infection parameter, interleukin-6, and C-reactive protein in 20 cirrhotics with or without spontaneous bacterial peritonitis. The patient's condition was followed-up for 12 weeks after paracentesis. RESULTS: None of the 10 patients with spontaneous bacterial peritonitis presented with severe systemic signs of infection. Procalcitonin level in plasma, but not in ascites, was significantly higher in patients with spontaneous bacterial peritonitis compared to controls (0.74 +/- 0.6 vs. 0.2 +/- 0.1 ng/mL, P < 0.05). Interleukin-6 levels in ascites were similar between groups. C-reactive protein concentrations were higher both in plasma and in ascitic fluid in patients with spontaneous bacterial peritonitis compared to controls (85.3 +/- 63 vs. 18.6 +/- 19 mg/dL, 24.6 +/- 25 vs. 4.5 +/- 4 mg/dL, P < 0.05, respectively). Three patients with spontaneous bacterial peritonitis died, but the outcome was not related to the concentrations of biological markers. CONCLUSIONS: In spontaneous bacterial peritonitis, procalcitonin measurement is not an accurate diagnostic test, possibly due to the absence of systemic inflammatory response syndrome in this condition. In addition, the diagnostic value of C-reactive protein is limited by the wide overlap between values.

Adult↗
PubMedDate not supplied

Oropharyngeal decontamination decreases incidence of ventilator-associated pneumonia. A randomized, placebo-controlled, double-blind clinical trial.

Secondary pneumonia in patients requiring mechanical ventilation has a high morbidity and mortality. Diagnosis is difficult and treatment failure common; therefore, preventive measures are important. In a double-blind, placebo-controlled trial, we evaluated selective decontamination of the oropharynx with polymyxin B sulfate, neomycin sulfate, and vancomycin hydrochloride (PNV) in 52 patients requiring mechanical ventilation during a 3- to 34-day period (mean, 10 days). Either PNV or placebo was administered six times daily in the oropharynx. During the first 12 days of intubation, tracheobronchial colonization by gram-negative bacteria and Staphylococcus aureus, as well as pneumonia, occurred less frequently in the PNV than in the placebo group (16% vs 78%; P less than .0001). Hospital mortality was not different, but systemic antibiotics were prescribed less often in the PNV group and no resistant microorganism emerged. In these critically ill patients, topical oropharyngeal antibiotic application lowered the rate of ventilator-associated pneumonia by a factor of 5, probably by interrupting the stomach-to-trachea route of infection, and decreased the requirement for intravenous antibiotics.

Adult↗