Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pseudomonas cepacia infection in patients with cystic fibrosis (CF) has major significance in terms of infection control, psychosocial issues, and medical treatment. We describe three instances in which the diagnostic laboratory misidentified Xanthomonas maltophilia as P. cepacia in cultures of sputum from patients with CF. These errors were recognized when 3 (9%) of 32 isolates, which had all been identified as P. cepacia and had been submitted to the Canadian Pseudomonas Repository Laboratory (Vancouver, BC), were correctly identified there as X. maltophilia. Each of the three isolates grew well on P. cepacia media, turned a characteristic vivid pink color, were polymyxin-resistant, and were lysine-positive. All three were initially characterized incorrectly as oxidase-positive and DNase-negative. The diagnostic laboratory then reexamined 24 other isolates that had been identified as P. cepacia; complete biochemical testing confirmed that all were indeed P. cepacia. Because infection due to P. cepacia has major implications for patients with CF, when a possible strain of P. cepacia is isolated, careful and complete characterization should be performed.
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PMID:Xanthomonas maltophilia misidentified as Pseudomonas cepacia in cultures of sputum from patients with cystic fibrosis: a diagnostic pitfall with major clinical implications. 753 77

Alginate is a large molecular weight exopolysaccharide present in the purulent airway secretions of cystic fibrosis (CF) patients. This polymer, produced by some of the opportunistic pathogens associated with the recurrent lung infections characteristic of CF, has been suggested to effect an increase in the viscoelastic properties of purulent CF airway secretions. We have investigated the use of an enzyme targeted at this exopolysaccharide, an alginate lyase obtained from a bacterial source, to disrupt its polymeric nature and effect a change in the rheological properties of CF sputum in vitro. Expectorated sputum samples obtained from hospitalized CF patients were found to contain 80-200 micrograms alginate per ml sputum with no measurable endogenous alginate lyase activity. Treatment with exogenous alginate lyase prepared from a mucoid strain of Pseudomonas aeruginosa resulted in the disruption of alginate and a decrease in sputum viscoelasticity in a small percentage of the samples tested. Similar treatment of these samples with recombinant human deoxyribonuclease I to cleave DNA present in purulent sputum and the use of alginate extracted from sputum as an alginate lyase assay substrate suggested that the inability of the exogenous alginate lyase to disrupt sputum alginate was not due to substrate inaccessibility or an unresponsive substrate. Concentrations of Ca2+ and Zn2+ in alginate lyase-resistant sputum samples, determined by metal ion analysis, were found to inhibit enzyme activity in studies using seaweed alginate as a substrate. High concentrations of Ca2+ and Zn2+ in sputum samples initially resistant to lyase activity could be reduced significantly in some samples by dialysis and these same samples acquired sensitivity to the lyase. Other sputum samples did not show reduced concentrations of Ca2+ and Zn2+ following dialysis and these samples remained lyase-insensitive. Together, these results suggest that bacterial alginate present within purulent CF sputum may be quite stable, that endogenous alginate lyase activities appear to be limited and that the in vitro addition of exogenous alginate lyase can lead to the disruption of alginate and a change in the viscoelastic properties of some purulent CF sputum samples.
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PMID:Addition of a bacterial alginate lyase to purulent CF sputum in vitro can result in the disruption of alginate and modification of sputum viscoelasticity. 754 23

Chronic pulmonary infection is the major cause of morbidity and mortality in cystic fibrosis (CF). Recombinant human deoxyribonuclease (rhDNase) in vitro has been shown to dramatically reduce the viscoelasticity of the sputum from CF patients. Phase II and III clinical trials have shown the drug to be safe, and that patients with a forced vital capacity (FVC) of > 40% predicted show an improvement in pulmonary function when receiving rhDNase. The current study evaluates the safety and efficacy of rhDNase in the most severly ill CF patients (FVC < 40% predicted). A double-blind, randomized, placebo-controlled trial in which patients received either 2.5 mg rhDNase twice daily or placebo for a period of 14 days followed by a 6 month open extension period (OEP) is reported. Seventy patients were recruited for the double-blind study, and 64 entered the OEP of whom 38 completed. During the OEP, all patients received 2.5 mg rhDNase twice daily. In both the double-blind period and the OEP the drug appeared to be safe. During the double-blind study, forced expiratory volume in one second (FEV1) and FVC improved in both groups but there was no statistically significant difference between the groups. In the OEP, there was mean improvement in percentage predicted FEV1 and FVC, 9 and 18%, respectively, for all patients participating. In conclusion, DNase is safe when administered in conjunction with a rigorous regimen of chest physiotherapy to severely ill patients (FVC < 40% predicted) with CF. The double-blind, 14 day study showed no significant improvement in pulmonary function but some patients may have improved after longer administration of rhDNase.
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PMID:Recombinant human DNase I in cystic fibrosis patients with severe pulmonary disease: a short-term, double-blind study followed by six months open-label treatment. 758 82

Cystic fibrosis (CF), a lethal disease common to Caucasians, is characterized by a defect in the CF transmembrane conductance regulator and the resulting defective cAMP-regulated Cl- secretion by epithelial cells. Clinical manifestations include both pancreatic and pulmonary insufficiency. Traditional therapeutic modalities address these problems with pancreatic enzyme replacement, vitamins and nutritional supplementation, antibiotics, and respiratory therapy. However, newer therapies directed at the specific underlying defects have emerged. In this review, we discuss agents that increase Cl- secretion via preserved Cl- secretory pathways, such as uridine triphosphate, or that enhance Na+ resorption, such as amiloride, thereby correcting altered airway secretions. We also discuss agents, including deoxyribonuclease (DNase), that directly reduce sputum viscosity. CF is an early target for in vivo gene therapy, since it is a monogenic autosomal recessive disease in which restoration of normal cAMP-regulated Cl- conductance can be achieved by complementation with a normal gene. The early clinical gene therapy therapy work, with gene introduction by both viral and nonviral vectors, is discussed.
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PMID:Molecular strategies for therapy of cystic fibrosis. 759 94

Numerous reagents are used in the collection processing and storage of hematopoietic progenitor cells for transplantation. To decrease potential variations in the final component for transplantation, these reagents should be uniform in safety, potency, and efficacy. Pharmaceutical-grade reagents are ideal but often are not available. Recently, recombinant human deoxyribonuclease (DNase) was approved for the treatment of patients suffering from the pulmonary complications of cystic fibrosis. We tested this pharmaceutical for toxicity to hematopoietic progenitor cells. These cells were exposed to a range of incubation concentrations for both the recombinant enzyme and bovine DNase previously used in this laboratory. No loss of nucleated cells or hematopoietic progenitors was observed after short-term incubation (1 h) or with direct addition to the culture medium. No incremental toxicity was observed in using recombinant enzyme with murine anti-B cell antibodies and rabbit complement in an immunologic purge technique. A variable effect on cell recovery after thawing of cryopreserved bone marrow cells was observed for both enzyme sources. These data suggest that the pharmaceutical-grade, recombinant human DNase may substitute for previously used reagent-grade protein from animal sources.
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PMID:Recombinant human deoxyribonuclease for hematopoietic stem cell processing. 763 47

The prognosis of cystic fibrosis has dramatically improved during the last three decades. This improvement was due to optimization of symptomatic treatment: antibiotics to combat infection, nutritional support, emphasis on bronchial drainage by physiotherapy and aerosols. The discovery of the gene responsible for the disease and the encoded protein opens the way to a specific and curative approach based upon the knowledge of the intrinsic properties of the protein, and its role in ionic flux. Recently, owing to the development of bioengineering, a recombinant human DNase has become available for clinical use. When aerosolized in the patients, it leads to deep changes in rheological parameters of the secretions that facilitate bronchial drainage and clearing of the airways. Gene therapy, the ultimate expression of these advances, will soon enter the era of clinical applications. Unsolved methodological and ethical issues still preclude immediate use in the patients. The results of transplantation surgery have also dramatically improved since the beginning. Indications are more precisely defined and restricted to the more advanced forms of the disease, according to severe criteria of inclusion.
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PMID:[Perspective of use of rhDNase and new therapeutics for cystic fibrosis]. 766 61

The discovery of the cystic fibrosis gene has provided new approaches to gene therapy and drug therapy. At the present time, however, we are still faced with the morbidity and mortality due to lung infections caused by Pseudomonas aeruginosa and Pseudomonas cepacia. The present survey of some of the recently published articles shows that applied science related to the clinical care of cystic fibrosis (CF) patients is also progressing. Cross-infection in CF centers and during social contacts between CF patients out of the hospital environment has been described in some countries. Prophylactically, cohort isolation procedures are effective. The individual clinical course of the chronic pulmonary infection is adversely influenced during prediabetic mellitus periods and by development of high titers of specific IgG2 and IgG3 antibodies against P. aeruginosa. A vaccine against P. aeruginosa is currently being tested in CF patients. The induced antibodies have much higher affinity and opsonophagocytic activity than infection-induced antibodies. Ciprofloxacin, which is widely used in CF, easily gives rise to resistance in P. aeruginosa and Staphylococcus aureus. Restricting the use of this drug in CF is therefore necessary. Aerosolized recombinant DNase is a promising and efficient new drug for management of airflow limitation due to purulent airway secretion in CF. For end-stage CF, double-lung and heart-lung transplantation show encouraging intermediate-term results, the two main obstacles being donor organ shortage and obliterative bronchiolitis.
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PMID:Cystic fibrosis and endobronchial pseudomonas infection. 769 Jun 37

The genetic determinant for the soluble pyocin S3 was isolated from a genomic library constructed in the plasmid pGV1122, of Pseudomonas aeruginosa strain P12 isolated from a cystic fibrosis patient. The nucleotide sequence of a 3270-base pair DNA fragment was determined, and the two structural genes, pyoS3A and pyoS3I, and the 3'- and 5'-flanking regions were localized. Transcription (Northern blot) analysis showed that the two genes were co-transcribed. The genes pyoS3A and pyoS3I code for polypeptides of 767 and 154 amino acids, respectively, with calculated molecular weights of 81,385 and 17,047. Pyocin S3 was produced in Escherichia coli from a plasmid and purified as a complex of two components (S3A and S3I) corresponding to the pyoS3A and pyoS3I gene products, respectively. The S3A component, like pyocin S3, had a killing effect involving DNase activity and was inhibited by the S3I protein. Comparisons of the predicted amino acid sequence of the two components of pyocin S3 to those of pyocins S1, S2, and AP41 indicate that pyocin S3 is a new type of S-type pyocin.
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PMID:Molecular characterization of pyocin S3, a novel S-type pyocin from Pseudomonas aeruginosa. 772

Recombinant human deoxyribonuclease (rhDNase) has been demonstrated to reduce the viscosity of purulent cystic fibrosis (CF) respiratory mucus, to improve pulmonary function and to reduce the risk of respiratory tract infectious exacerbations, but its effect on mucus transportability has not so far been investigated. The dose-dependent effect of rhDNase was analysed in vitro on mucus transport rate (tr) by ciliary activity and by simulated cough (cough transport (ct)), as well as on mucus viscosity and surface properties. Purulent CF sputa (n = 15) were incubated for 30 min at 37 degrees C with either rhDNase at three different concentrations (final concentrations 0.2, 2 or 20 micrograms.ml-1 of mucus) or placebo. No significant dose-dependent effect of rhDNase on the mucociliary transport rate was observed when the samples wer statistically analysed together. However, in the larger group of mucus samples (n = 11) with a low initial mucociliary transport rate, the latter was improved at each rhDNase concentration (tr0.2 = 0.69, tr2 = 0.88 and tr20 = 0.87) as compared to placebo (trp = 0.58). In the smaller group of mucus samples (n = 4) with high initial transport rate, a decrease in mucociliary transport rate was observed, particularly at the highest concentration rhDNase assayed, i.e. 20 micrograms.ml-1 of mucus (tr20 = 0.58) as compared to placebo (trp = 0.86). The mucus cough transport was increased by rhDNase (ct0.2 = 25 mm, ct2 = 27.5 mm and ct20 = 31 mm) as compared to placebo (ctp = 23.5 mm).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dose-dependent in vitro effect of recombinant human DNase on rheological and transport properties of cystic fibrosis respiratory mucus. 778 81

The airway secretions which line the respiratory tract form a biphasic layer composed of an aqueous 'sol' layer and a more superficial 'gel' layer. In the sol layer, also described as the 'periciliary' layer or 'airway surface fluid', the cilia beat and relax. The lubricant sol layer enables the gel mucus present at the tips of the cilia to be transported by the ciliary beating of the ciliated cells. Due to difficulties with sampling, little is known about the physical and biochemical properties of the sol layer. The gel layer is composed of high molecular weight glycoproteins (mucins) linked with proteins and lipids. They form a gel network with a high water content (95%) and rheologic and physical properties (viscoelasticity, adhesivity) adapted in normal conditions to protect the airway mucosa, particularly through mucociliary transport. The adhesive properties of mucus, which are influenced by its lipid composition and degree of hydration, are very important in controlling the efficacy of mucus transport through ciliary activity and coughing. An intermediate viscosity and elasticity is required for optimal mucociliary transport. In obstructive airway diseases, either of genetic origin, such as cystic fibrosis (CF), or acquired (acute or chronic bronchitis), and particularly during inflammatory and infectious episodes, mucus dehydration is associated with an increase in secreted or transudated molecules and with marked augmentation of DNA content. These abnormalities contribute to the increased viscosity and adhesivity of the airway secretions and are responsible for their abnormally low transport rate by ciliary activity and for inefficient cough clearance. In view of these alterations in the physical and functional properties of CF airway secretions, pharmacologic approaches should aim to rehydrate the mucus and to restore normal mucociliary or cough transport by stimulating chloride ion secretion (i.e. using UTP or ATP associated with amiloride in order to block sodium ion and water reabsorption). During acute episodes of infection, recombinant human DNase (rhDNase) may rapidly prevent mucus stasis by improving its rheologic properties. Lubrication of the mucus at the sol phase interface by 'surfactant' therapy may also represent a very promising therapeutic perspective to reduce the hyperviscosity and hyperadhesivity of airway secretions.
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PMID:Physical and functional properties of airway secretions in cystic fibrosis--therapeutic approaches. 779 36


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