[Neutrophils: mediators of bronchial destruction in patients with cystic fibrosis].
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Biomedical subjects
Publications and source records attributed to S Suter.
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The chronic, progressively destructive bronchitis of patients with cystic fibrosis (CF) is characterized by an important imbalance between tissue destroying granulocyte proteases such as granulocyte elastase (GE) and its physiological inhibitors in bronchial secretions. Recent in vitro studies suggest, that proteases derived from bacteria or endogenous proteases may contribute to inactivation of physiological inhibitors of GE. Since only trypsin-unreactive alpha 1-proteinase inhibitor (alpha 1-PI) was detected in CF bronchial secretions, we attempted to identify the mechanism of inactivation of alpha 1-PI. We found a heat stable, serine protease-like enzymatic activity capable of degrading 125I-labelled alpha 1-PI extensively in 22 infected but not in one non-infected CF bronchial secretion. In infected secretions, only degraded alpha 1-PI, which did not migrate like oxidized alpha 1-PI in tandem-crossed immunoelectrophoresis, was detectable. We conclude, that free GE in excess as well as GE bound to bronchial mucosal inhibitor may partly account for the alpha 1-PI-cleaving activity, but that other yet unknown bacterial or host serine proteases also contribute to alpha 1-PI inactivation.
We report a retrospective study of invasive Haemophilus influenzae type b (Hib) diseases in Geneva from 1976 to 1989. Among the 183 children who fulfilled the case definition, 6 (3.3%) presented with more than one site of infection. The overall incidence rate among children younger than 5 years of age was 60.2/100,000 but it was 92.1/100,000 in 1989. Forty-one percent of patients had meningitis, 37% had epiglottis and 22% had other forms of Hib infections. Fifty-four percent of cases occurred in children younger than 2 years of age. Invasive Hib infections were found more often in boys than in girls (1.6/1). From 1984, 21% of all Hib were beta-lactamase-producing strains. During the study period 2 children (1.1%) died from epiglottitis and 12 children with meningitis (15.8%) developed serious neurologic deficits. These data suggest that administration of a conjugate vaccine against Hib to all infants living in Geneva is justified.
Recurrent hypovolaemic shock had been occurring over the last five and four years, respectively, in a 53-year-old woman and a 46-year-old man who had previously been healthy. The attacks were characterized by a tension feeling and sometimes oedema in the limbs, as well as increased thirst. Within a few hours sweating, tachycardia, orthostatic complaints and shock would occur. The woman's systolic blood pressure would fall to 70 mm Hg and the pulse rate rise to 150/min. The man's blood pressure was not measurable by sphygmomanometer during his first attack. Haematocrit rose to 61 and 71.5%, haemoglobin concentration to 20.7 and 21.3 g/dl, respectively. On administration of plasma expanders all abnormal clinical and biochemical changes quickly disappeared, only to recur within weeks or months. The cause of the condition is an increased permeability of the tissue capillaries, while renal, pulmonary and cerebral vessels apparently are unaffected. During ketotifen and tebonin (gingko biloba extract) administration to the man, he required no further hospitalization for nine months, after which he had three severe attacks. The woman had a severe attack of hypovolaemic shock one month on this treatment. The prognosis of capillary leak syndrome is bad.
To compare ceftriaxone with cefuroxime for the treatment of meningitis, we conducted a study in which 106 children with acute bacterial meningitis were randomly assigned to receive either ceftriaxone (100 mg per kilogram of body weight per day, administered intravenously once daily; n = 53) or cefuroxime (240 mg per kilogram per day, administered intravenously in four equal doses; n = 53). The mean age of the children was 3 years (range, 42 days to 16 years), and the characteristics of the two treatment groups were comparable at admission. Excluded from the study were eight other children who died within 48 hours of admission. After 18 to 36 hours of therapy, cultures of cerebrospinal fluid remained positive for 1 of the 52 children (2 percent) receiving ceftriaxone for whom cultures were available and 6 of 52 (12 percent) receiving cefuroxime (P = 0.11). In both groups the mean duration of antibiotic therapy was 10 days. The clinical responses to therapy were similar in the two treatment groups, and all 106 children were cured. Reversible biliary pseudolithiasis was detected by serial abdominal ultrasonography only in the children treated with ceftriaxone (16 of 35 vs. 0 of 35; P less than 0.001). The treatment of three children was switched from ceftriaxone to alternative antibiotics because these children had upper abdominal pain. Other side effects were infrequent in both groups. At follow-up examination two months later, moderate-to-profound hearing loss was present in two children (4 percent) treated with ceftriaxone and in nine (17 percent) treated with cefuroxime (P = 0.05); other neurologic abnormalities were similar in the two treatment groups. We conclude that ceftriaxone is superior to cefuroxime for the treatment of acute bacterial meningitis in children and that the benefits of milder hearing impairment and more rapid sterilization of the cerebrospinal fluid with ceftriaxone outweigh the problem of reversible biliary pseudolithiasis with this drug.
We report three cases of neonatal herpes simplex virus (HSV) infection presenting as fulminant hepatitis. None of the patients had clear risk factors for HSV infection and they all died. Antiviral treatment for HSV is currently available but must be administered early in the course of the disease before irreversible liver tissue damage is present. Since the diagnosis may be difficult to establish, we wish to draw the attention of clinicians to the presentation of neonatal HSV infection and suggest that in such cases viral cultures, including culture of liver tissue, should be obtained early and antiviral treatment administered while awaiting the culture results.
Tumour necrosis factor-alpha (TNF-alpha) is an important mediator in the pathogenesis of Gram-negative shock. In order to assess the role of TNF-alpha as a marker of the severity of infections in the neonates, serum TNF-alpha concentrations were determined at the time of septic work-up in 69 newborns (gestational age: 28-40 weeks). Nine patients had systemic infection (group A), four of them with signs of circulatory failure. Eleven patients had positive cultures of gastric aspiration or placental smears (group B) and 49 patients had completely negative septic work-up. Patients of group A had significantly more elevated serum TNF-alpha levels than patients of group B and C. Within group A, patients with circulatory failure had mean serum TNF-alpha concentration of 2165 +/- 817 pg/ml versus 27 +/- 8 pg/ml in newborns without shock. Serum TNF-alpha concentrations of more than 15 pg/ml detected systemic infections in eight out of nine patients. The specificity was 98% (1 elevated TNF-alpha concentration out of 60 non infected patients). These data indicate that premature neonates and term newborns are able to produce TNF-alpha when they are infected. Highly elevated TNF-alpha concentrations are found in severe systemic infections causing cardiovascular impairment.
Pregnancy-associated plasma protein A (PAPP-A), was reported to be an inhibitor in many in vitro systems. Since it was shown that the inhibition of coagulation and complement activity attributed to PAPP-A was in fact due to a contamination by heparin occurring during the purification process, we undertook the present study to see whether the reported PAPP-A-induced inhibition of human leukocyte elastase (HLE) could also be attributed to heparin contamination. PAPP-A was purified from maternal pregnancy EDTA plasma by a method which was previously shown to eliminate contaminating heparin: this preparation was inactive in the HLE assay. But PAPP-A isolated by heparin-Sepharose chromatography, or a PAPP-A-free washing of the heparin-Sepharose column were both inhibitors of HLE. Furthermore the inactive PAPP-A preparation, when incubated with the PAPP-A-free washing of the heparin-Sepharose column, yielded a high molecular weight preparation which inhibited HLE. It is concluded that PAPP-A is not an inhibitor of HLE and that the inhibition of HLE previously attributed to PAPP-A was due to contaminating heparin.
Recently, it has been suggested that the primary metabolic defect of cystic fibrosis (CF) is in the metabolic steps between an elevation of cyclic adenosine monophosphate (cAMP) and the opening of the Cl- ion channel in airway epithelial cells. Results from other studies have indicated that the primary defect may also be present in polymorphonuclear leukocytes (PMNL). In PMNL, cAMP is a potent inhibitor of cell function. We therefore used three compounds (epinephrine, theophylline, and forskolin) known to elevate cAMP in PMNL by three different mechanisms, to study the effect of an elevation of cAMP on various cell functions, such as superoxide production, membrane depolarization, and degranulation of CF patient PMNL and PMNL from healthy individuals. The baseline rates of superoxide production, degranulation, and membrane depolarization were identical for CF and control PMNL. After exposure to epinephrine as well as theophylline plus forskolin, the cell function of CF PMNL was inhibited to the same extent as that of control PMNL. Our results argue against an abnormal response of PMNL from patients with CF to an elevation of cAMP.
A newborn with fatal neonatal listeriosis developed septic shock, neutropenia, thrombocytopenia and profound hypoxaemia due to severe pulmonary hypertension. Tumour necrosis factor alpha, interleukin-1-beta and interferon-gamma serum concentrations were markedly elevated, suggesting the participation of these cytokines in the aetiopathogenesis of shock induced by Listeria monocytogenes in the neonate.
A patient with Salmonella muenchen sepsis was unsuccessfully treated with ampicillin. During therapy, four strains that showed stepwise ampicillin resistance and affected other beta-lactams and unrelated antibiotics were isolated sequentially. Resistance was caused by decreased outer membrane permeability associated with diminished expression of porin OmpF. Furthermore, the most resistant isolate overproduced the PBP 3 target molecule.
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Patients with cystic fibrosis suffer from a chronic, progressively destructive bronchitis characterized by colonization of the airways by Pseudomonas aeruginosa. Cell wall lipopolysaccharides from P. aeruginosa may stimulate secretion of cytokines such as tumor necrosis factor alpha (TNF alpha) by monocytes/macrophages. We found elevated levels of TNF alpha (150 +/- 60 pg/ml), interleukin-1 alpha (144 +/- 205 pg/ml), and interleukin-1 beta (62 +/- 100 pg/ml) in plasma from 25 patients with cystic fibrosis. In patients with less advanced disease, elevated plasma levels of TNF alpha correlated with high levels of complexes between neutrophil elastase and alpha 1-proteinase inhibitor, suggesting that TNF alpha may be a mediator of neutrophil degranulation. TNF alpha, by its chemotactic effect on neutrophils, may also contribute to the massive influx of neutrophils into and around the bronchial tree. Our findings raise the questions whether in patients with cystic fibrosis TNF alpha acts as cachectin and whether it mediates the anorexia that often results in weight loss.
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In cystic fibrosis, colonization of the airways with Pseudomonas aeruginosa follows colonization with Staphylococcus aureus and is related to accelerated deterioration of pulmonary function. Because P. aeruginosa adheres better to cell surfaces devoid of fibronectin, we searched for fibronectin-cleaving activity in bronchial secretions and saliva from 24 patients with cystic fibrosis who were followed up for 4.5 y and from two control groups. Proteolytic activity against 125I-labeled fibronectin was continuously present in cystic fibrosis bronchial secretions; significantly higher fibronectin-cleaving activity was found in older vs. younger patients, in patients with advanced disease stages determined by a five-stage scoring system, and in those colonized with P. aeruginosa. The fibronectin-cleaving activity was due to neutrophil elastase and cathepsin G. Cystic fibrosis bronchial secretions had proteolytic activity against surface fibronectin of airway mucosal cells. Thus fibronectin-cleaving activity of bronchial secretions rather than of saliva may favor P. aeruginosa colonization of the upper respiratory tract in individuals with cystic fibrosis.
Eglin C is an inhibitor of polymorphonuclear leukocyte elastase and cathepsin G. Recently, it was suggested that Eglin C may inhibit bacterial clearance in an experimental animal model of pneumonia. Since the phagocytic-bactericidal activity of polymorphonuclear leukocytes is most important in the promotion of bacterial clearance, we determined the effect of Eglin C on a variety of functions of isolated human polymorphonuclear leukocytes such as phagocytic-bactericidal activity, superoxide production, degranulation and chemotaxis. Apart from a partial inhibition of superoxide production, which was shown to be due to a superoxide dismutase-like effect of Eglin C, there was no inhibition of polymorphonuclear leukocyte functions measured. Eglin C can therefore be considered as a protease inhibitor, which does not interfere with the phagocytic-bactericidal activity of human polymorphonuclear leukocytes.
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The choice of treatment, the importance of chemoprophylaxis in household contacts and the potential impact of immunization with vaccines against Haemophilus influenzae type b (Hib) currently under investigation are discussed on the basis of the patients hospitalized for invasive Hib infections at the University Children's Hospital Geneva from 1976 to 1985. Among 122 culture-proven infections due to Hib, there were 41% of cases of meningitis, 37.7% of epiglottitis, 9.8% of pneumonia, 5.7% of septicemia, 3.3% of cellulitis and 2.4% of septic arthritis. From 1981 to 1983, one strain of Hib produced beta-lactamase, but between 1984 and 1985, 5 strains (19.2%) produced beta-lactamase. Only one case of possible horizontal transmission of the infection was found in this 10-year period. We conclude that 1. the appearance of beta-lactamase producing strains of Hib requires that treatment be initiated with an antimicrobial agent resistant to beta-lactamase when a Hib infection is suspected; 2. in our region, only one case of an invasive Hib infection could theoretically have been prevented by chemoprophylaxis; and 3. the calculated theoretical impact of vaccination with the new types of vaccines against Hib could have prevented 106 of 122 cases of invasive Hib infections.