American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Oct 1996
ReviewPertussis antigens that abrogate bacterial adherence and elicit immunity.
Infectious disease processes follow the initial steps of adherence of the organism to host tissues and subsequent colonization of the target tissues that can occur through specific adhesion-receptor systems. Bordetella pertussis, the human pathogen that causes whooping cough, has evolved a genetically controlled system whereby adhesins are expressed when they enter the human host. ⋯ Substantial evidence exists that the B. pertussis adhesins, FHA and pertactin, elicit immune responses that are protective in animal models for the disease, including serum antibody production and local immune responses in the respiratory tract following nasal administration of encapsulated antigens. Both of these adhesins are components of new acellular pertussis vaccines that have proven safe and highly effective for prevention of serious disease in infants.
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Am. J. Respir. Crit. Care Med. · Oct 1996
The accuracy of elevated concentrations of endotoxin in bronchoalveolar lavage fluid for the rapid diagnosis of gram-negative pneumonia.
The purpose of this study was to determine the accuracy of elevated concentrations of endotoxin in bronchoalveolar lavage (BAL) fluid for the diagnosis of gram-negative pneumonia. Sixty-three hospitalized adults underwent 71 evaluations with BAL using quantitative cultures for suspected lung infection. A cutoff value of > 5 EU/ml for the concentration of endotoxin in BAL fluid yielded the best operating characteristics for the diagnosis of gram-negative pneumonia (sensitivity, 100%; specificity, 75.0%; area under receiver operating characteristic [ROC] curve, 0.88). ⋯ Gram stain examination of BAL fluid for the presence of gram-negative bacteria yielded inferior operating characteristics (sensitivity, 63.2%; specificity, 75.0%; area under ROC curve, 0.69). Poor diagnostic agreement was observed between BAL fluid Gram stain results and microbiologically confirmed gram-negative pneumonia (kappa statistic, 0.35; concordance, 71.8%). These findings suggest that a concentration of endotoxin in BAL fluid > 5 EU/ml is superior to Gram stain examination for the rapid identification of patients with gram-negative pneumonia.
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Am. J. Respir. Crit. Care Med. · Oct 1996
Microcirculatory changes in rat skeletal muscle in sepsis.
The aim of this study was to confirm that microvascular perfusion was abnormal during the early phases of normotensive sepsis and to determine whether these changes were due to the development of tissue edema. Skeletal muscle red blood cell (RBC) flow was studied in rats made septic by cecal ligation and perforation (CLP). After anesthesia with halothane, arterial and venous cannulae were inserted and, in the treatment group, a CLP performed. ⋯ This study shows that sepsis was associated with increased RBC flow heterogeneity. These changes, which occur within 24 h of the septic insult, are a persistent feature of the evolving septic process in the absence of tissue edema. These observations support the view that extrinsic compression of the microcirculation by tissue edema is not the primary cause of alterations in microcirculatory flow in sepsis.
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Am. J. Respir. Crit. Care Med. · Oct 1996
Chest wall compliance in infants and children with neuromuscular disease.
Respiratory muscle weakness is the primary cause of respiratory dysfunction in neuromuscular disease (NMD), but structural abnormalities of the chest wall also play a role. In adults with NMD, restrictive lung disease is in part caused by reduced chest wall compliance (C(W)), believed to reflect stiffening of connective tissue resulting from chronically reduced chest wall motion in the presence of respiratory muscle weakness. We hypothesized that chronic limitation of chest wall motion in young children with NMD leads to structural underdevelopment of the chest wall, and results in increased, rather than decreased, C(W). ⋯ C(W)/kg was higher in subjects with NMD than in controls, at 5.2 +/- 2.8 (mean +/- SD) versus 2.4 +/- 0.8 ml/cm H2O (p < 0.001). In subjects who had normal lung compliance values during spontaneous breathing (C(Lspont)), C(W)/C(Lspont) was significantly greater in subjects with NMD (5.5 +/- 3.2) than in controls (1.9 +/- 1.0) (p < 0.001). By predisposing to rib cage deformation and reduced end-expiratory lung volume, abnormally high C(W) in infants and young children with NMD may contribute to respiratory dysfunction.