Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021311 (Infection)
 38,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The amiloride-sensitive epithelial sodium channel (ENaC) mediates Na(+) reabsorption in many epithelial tissues including the distal nephron, colon, lung, and secretory glands and plays an important role in pathophysiology of hypertension and cystic fibrosis. The ENaC is a multimeric integral membrane protein formed by the association of highly homologous,alpha-, beta-, and gamma-ENaC subunits. Here we explored the Sf9 insect cell-baculovirus expression system as a source to obtain high yields of recombinant ENaC for functional and structural studies. Although this expression system is widely used, coexpression of ENaC subunits could not be accomplished by the conventional procedures. We thus developed a protocol in which the alpha- and gamma-ENaC cDNA's were first fused individually with polyhedrin promoters at their 5'-ends and then inserted in the multiple cloning sites of pVL1393 transfer vector carrying the beta-ENaC cDNA. Utilizing this transfer vector, a recombinant baculovirus carrying all of the three ENaC cDNA's was prepared. Infection of Sf9 insect cells with this recombinant baculovirus resulted in the expression all of the three ENaC subunits in high yield. Planar lipid bilayer reconstitution procedure revealed the presence of approximately 6 pS sodium channels that are amiloride-sensitive. The results presented point out certain underlying rules for the expression of multiple genes in Sf9 cells, which may be useful in the expression other multimeric proteins and in the studies of protein-protein interactions as well.
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PMID:Expression of amiloride-sensitive sodium channel: a strategy for the coexpression of multimeric membrane protein in Sf9 insect cells. 1106 42

Infection of the cystic fibrosis (CF) airways elicits an exaggerated, interleukin-8 (IL-8) mediated, neutrophil inflammatory response. Necrosing neutrophils release DNA and actin into the airways, increasing the viscoelasticity of airway secretions. Mucolytics aim to improve airway clearance by reducing this viscoelasticity. DNase I reduces the viscoelasticity of CF sputum, and a human recombinant form of this enzyme is widely administered to patients with CF. Gelsolin, which cleaves actin polymers, is also known to reduce CF sputum viscosity in vitro, and it has been proposed as a future mucolytic agent. We have shown that the anionic polymers DNA and actin bind and mask immunologic recognition of the basic peptide IL-8 and prevent this chemokine from binding to neutrophil receptors. Reduction of CF sputum viscosity by DNase I or gelsolin in vitro was demonstrated to increase the proportion of free IL-8 and the IL-8-dependent neutrophil chemotactic activity of sputum supernatants. We hypothesize that an electrostatic interaction between polymer and chemokine may limit the inflammatory potential of the latter, but that this interaction may be weakened by polymer cleavage. The potential risk of increased inflammation via this mechanism suggests a caveat should be attendant on treatment of patients with CF with these mucolytic agents.
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PMID:DNA and actin bind and inhibit interleukin-8 function in cystic fibrosis sputa: in vitro effects of mucolytics. 1106 10

Pseudomonas aeruginosa is a non-capsulate and non-sporing gram-negative bacillus that most commonly affects the lower respiratory system in humans. Burkholderia (previously Pseudomonas) cepacia has emerged as an important respiratory pathogen in patients with cystic fibrosis (CF). The ability of P. aeruginosa to persist and multiply in moist environments and equipment, such as humidifiers in hospital wards, bathrooms, sinks and kitchens, maybe of importance in cross-infection. P. aeruginosa infections of the lower respiratory tract can range in severity from colonisation (without an immunological response) to a severe necrotising bronchopneumonia. Infection is seen in patients with CF and other chronic lung diseases such as non-CF bronchiectasis. In patients with CF, once P. aeruginosa is established in the airways it is almost impossible to eradicate, but prior to this, aggressive treatment can delay the development of chronic infection. 30 to 40% of the present paediatric population with CF will have chronic pseudomonal infection. B. cepacia has a particular predisposition to infect patients with CF and may be distinguished from P. aeruginosa by accelerated lung disease in about one- third of patients. Overwhelming septicaemia and necrotising pneumonia are well described (cepacia syndrome); events that are rare with P. aeruginosa. With the propensity for social cross-infection, segregation policies have been accepted as means of controlling outbreaks. A number of antipseudomonal agents are available. The most commonly used are the extended-spectrum penicillins, aminoglycosides, cephalosporins, fluoroquinolones, polymixins and the monobactams. An aminoglycoside with a beta-lactam penicillin is usually considered to be the first line treatment. No trial has shown any significant clinical advantage of any particular combination regimen over another. The emergence of resistance continues to be a concern. Pipericillin, piperacillin/tazobactam and meropenem have good but equivalent antibacterial activity against P. aeruginosa. However, B. cepacia is characterised by in vitro resistance to colistin (colomycin), aminoglycosides and ciprofloxacin but better susceptibility to ceftazidime. Nebulised delivery of antipseudomonal antibiotics is thought to prevent recurrent exacerbations, reduce antibiotic usage and maintain lung function, particularly in patients with CF. Colistin, tobramycin and gentamicin are currently the most commonly prescribed nebulised antibiotics. Much effort is directed at treating chronic P. aeruginosa infection but as chronic infection is seldom if ever eradicated when first established, prevention is preferable. Early intensive treatment for P. aeruginosa infection is advocated in order to maintain pulmonary function and postpone the onset of chronic P. aeruginosa infection.
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PMID:The treatment of respiratory pseudomonas infection in cystic fibrosis: what drug and which way? 1112 22

Pulmonary infection with Pseudomonas aeruginosa in patients with cystic fibrosis (CF) causes a chronic destructive bronchitis. A xenograft model was used to study the susceptibility of the CF respiratory epithelium to P. aeruginosa strain PAK and the virulence of certain mutants. Despite an early trend toward increased susceptibility, colonization of CF xenografts (ID(95), 62 colony-forming units [cfu]) was not statistically different (P=.5) than in xenografts with normal respiratory cells (ID(95), 1.2x10(3) cfu). Infection severity in 12 CF xenografts (mean polymorphonuclear leukocyte [PMNL] density, 1.88x10(6)+/-1.75x10(6)/xenograft) was similar to that in 16 non-CF xenografts (3.19x10(6)+/-2.45x10(6) PMNL/xenograft; P=.38), despite slightly greater bacterial density in the CF xenografts (mean, 1.57+/-2.73x10(6) cfu/xenograft) versus xenografts with normal epithelium (mean, 1.03+/-1.3x10(6) cfu/xenograft). P. aeruginosa mutants pilA and fliF, but not rpoN, colonized normal respiratory xenografts, indicating that colonization and infection in this model depend on an uncharacterized RpoN-controlled gene. This model appears to be suitable for genetic study of P. aeruginosa virulence but not of the CF respiratory tract's unique susceptibility.
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PMID:Pseudomonas aeruginosa infection of respiratory epithelium in a cystic fibrosis xenograft model. 1123 9

Infection by Burkholderia cepacia is sometimes fatal in patients with cystic fibrosis (CF), as the organism can cause necrotising pneumonia and septicaemia (the cepacia syndrome), and is resistant to antibiotics. To increase knowledge of the pathogenesis of lung infection, the present study investigated the distribution of B. cepacia in lung explants from nine CF recipients of double lung transplants, of which six were colonised with both B. cepacia and Pseudomonas aeruginosa and the other three with P. aeruginosa only. In one case, explants of the donor lung (allograft) became available after the patient succumbed post-operatively to the cepacia syndrome. Further autopsy sections were examined from two patients who had chronic and then acute infection with B. cepacia. A specific antibody reactive with all five genomovars of the B. cepacia complex and another antibody specific for the 22-kDa adhesin of cable pili, were used to localise bacteria in situ. In chronic infection, the organisms were diffusely distributed, but most concentrated in hyperplastic bronchiolar epithelium, inflamed peribronchial and perivascular areas, between adjacent airway epithelial cells and in pathologically thickened alveolar septae and luminal macrophages. In acute infections the distribution was more focal, with B. cepacia on injured airway surfaces and in sites of pneumonia and abscess formation. In autopsy sections from one of the patients with chronic, then acute infection, B. cepacia was also observed in the lumen of blood capillaries. These results suggest that B. cepacia has the capacity to be highly invasive, migrating from the airways across the epithelial barrier to invade the lung parenchyma and capillaries, thereby initiating septicaemia.
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PMID:Immunolocalisation of Burkholderia cepacia in the lungs of cystic fibrosis patients. 1139 91

The prevalence of bronchiectasis (BR) has decreased significantly in industrialized countries, but is still commonplace in developing countries. We evaluated the causes and clinical features of BR in 23 children (13 boys (57%) and 10 girls (43%), with a mean age of 8.45 +/- 4.02 years). Infection was the major cause of BR in our region. In 8 patients, BR developed after tuberculosis or pneumonia, was associated with immune deficiency syndromes in 4 children, and with asthma in 4. Cystic fibrosis was diagnosed in 4 cases and ciliary dyskinesia in 3. In 10 patients, only one lobe was involved. Bronchiectatic lesions were most commonly found in the left lower lobe and were observed in 7 patients. Multilobar involvement was found in 13 patients. The initial treatment was primarily medical, but in 2 patients whose medical therapy failed, pulmonary resection was carried out. Three patients died from severe pulmonary infection and respiratory failure.
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PMID:Bronchiectasis: still a problem. 1147 35

Infection with transmissible strains of Pseudomonas aeruginosa can occur in uncolonised patients, but cross infection (superinfection) of patients already colonised withP aeruginosa has not been reported. With genotypic identification, we found superinfection by a multiresistant transmissible strain of P aeruginosa in four patients with cystic fibrosis (CF) who were already colonised by unique strains of P aeruginosa. No evidence of environmental contamination was found, but all patients became superinfected after contact with colonised individuals during inpatient stays. Inpatients with CF who are colonised with P aeruginosa should be separated by strain type. Such strain typing can only be reliably done by genomic methods, but this has resource implications.
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PMID:Superinfection with a transmissible strain of Pseudomonas aeruginosa in adults with cystic fibrosis chronically colonised by P aeruginosa. 1181 95

Infection with Burkholderia cepacia complex in patients with cystic fibrosis (CF) results in highly variable clinical outcomes. The purpose of this study was to determine if there are genomovar-specific disparities in transmission and disease severity. B. cepacia complex was recovered from 62 patients with CF on > or =1 occasions (genomovar III, 46 patients; genomovar II [B. multivorans], 19 patients; genomovar IV [B. stabilis], 1 patient; genomovar V [B. vietnamiensis], 1 patient; and an unclassified B. cepacia complex strain, 1 patient). Patient-to-patient spread was observed with B. cepacia genomovar III, but not with B. multivorans. Genomovar III strains replaced B. multivorans in 6 patients. Genomovar III strains were also associated with a poor clinical course and high mortality. Infection control practices should be designed with knowledge about B. cepacia complex genomovar status; patients infected with transmissible genomovar III strains should not be cohorted with patients infected with B. multivorans and other B. cepacia genomovars.
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PMID:Infection with Burkholderia cepacia complex genomovars in patients with cystic fibrosis: virulent transmissible strains of genomovar III can replace Burkholderia multivorans. 1158 91

The Burkholderia cepacia complex is an important group of pathogens in patients with cystic fibrosis (CF). Although evidence for patient-to-patient spread is clear, microbial factors facilitating transmission are poorly understood. To identify microbial clones with enhanced transmissibility, we evaluated B. cepacia complex isolates from patients with CF from throughout Canada. A total of 905 isolates from the B. cepacia complex were recovered from 447 patients in 8 of the 10 provinces; 369 (83%) of these patients had genomovar III and 43 (9.6%) had B. multivorans (genomovar II). Infection prevalence differed substantially by region (22% of patients in Ontario vs. 5% in Quebec). Results of typing by random amplified polymorphic DNA analysis or pulsed-field gel electrophoresis indicated that strains of B. cepacia complex from genomovar III are the most potentially transmissible and that the B. cepacia epidemic strain marker is a robust marker for transmissibility.
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PMID:Epidemiology of Burkholderia cepacia complex in patients with cystic fibrosis, Canada. 1189 71

Chronic endobronchial infection frequently caused by gram-negative organisms and an increased, neutrophil-dominated inflammation are characteristics of cystic fibrosis (CF). The present study examines endotoxin levels in bronchoalveolar lavage fluids of CF versus non-CF (N) control children, and correlates these with the inflammatory markers interleukin-8 and neutrophils. Fifty-five patients with CF and 56 patients without CF between the ages of 0.04 to 13.25 years were included. Infection, defined as a bacterial count above 50,000 cfu/ml, was present in 27 CF and 25 N patients. Endotoxin levels were not different between patients with and without CF (infected: 74.9 +/- 12.1 EU/ml versus 51.4 +/- 12.5 EU/ml, p = 0.16; noninfected: 5.9 +/- 4.8 EU/ml versus 11.1 +/- 4.3 EU/ml, p = 0.28). Endotoxin activity correlated to the number of gram-negative organisms in CF and N patients, and endotoxin activity per bacterial colony forming unit did not differ with various gram-negative species. Both interleukin-8 and neutrophils were positively correlated with endotoxin, but this slope was shifted toward higher levels of inflammation in CF patients. We conclude that it is unlikely that higher levels of endotoxin in the absence of viable bacteria explain the increased inflammatory response in CF.
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PMID:Endotoxin activity and inflammatory markers in the airways of young patients with cystic fibrosis. 1193 7


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