Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Nebulized recombinant human DNase (rhDNase) reduces sputum viscosity, improves pulmonary function, and results in a small reduction in acute respiratory exacerbations requiring intravenous antibiotics in many patients with cystic fibrosis (CF). rhDNase is now recommended for use in CF patients with moderately severe suppurative lung disease. A 14-year-old girl with suppurative lung disease [forced expiratory volume in 1 second (FEV1) 69% and forced vital capacity (FVC) 81% predicted] secondary to Kartagener's syndrome and severe gastroesophageal reflux had worsening spirometry together with intractable gastrointestinal symptoms over the previous 18 months despite conventional treatment. She was, therefore, started on 2.5 mg rhDNase once daily. Her cough lessened and the volume of sputum decreased within 72 hours of commencement of treatment; this improvement was strongly associated with a dramatic reduction in gastrointestinal symptoms. Spirometry after 4 weeks of treatment demonstrated a 20% improvement in FEV1 and a 13% improvement in FVC. These improvements have been maintained after 4 months of rhDNase therapy. The use of rhDNase should be considered in patients with Kartagener's syndrome and a multicenter trial may be justified.
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PMID:Clinical benefit from nebulized human recombinant DNase in Kartagener's syndrome. 890 3

In cystic fibrosis (CF), large amounts of free leucocyte proteases are present in bronchial secretions, contributing to progressive lung damage. Recombinant, human deoxyribonuclease (rhDNase) is a new therapeutic agent that decreases sputum viscosity. However, deoxyribonuclease has been shown, in vitro, to release cationic enzymes from complexes with deoxyribonucleic acid (DNA). The present study was conducted to assess this effect in vivo. Free human leucocyte elastase (HLE), human leucocyte cathepsin G (HCG), total chemotactic activity, and interleukin-8 (IL-8) were determined in sputum from eight patients before, during and after rhDNase treatment. After 15 days of treatment, HLE activity increased by 81+/-44% (NS), and HCG by 189+/-70% (p<0.05). One week after stopping a 4-6 months treatment, HLE activity decreased by 35+/-18% (p<0.05), and HCG by 43+/-11% (p<0.05). Sputum bacterial density, chemotactic activity, and IL-8 concentration did not change. Thus, treatment with rhDNase can indeed increase the activity of HLE and HCG in the bronchial secretions of CF patients, and this effect is still detectable after several months of treatment. If this can be shown to be clinically relevant, combination therapy of recombinant human deoxyribonuclease with protease inhibitors should be considered as an approach to the problem.
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PMID:Aerosolized rhDNase in cystic fibrosis: effect on leucocyte proteases in sputum. 894 60

Cystic fibrosis (CF) patients frequently experience recurring airway infections characterized by thick, viscous sputum. The consistency and nature of these purulent secretions may produce a significant barrier to the successful delivery of drugs and gene therapy vectors designed to treat CF. We have carried out a series of in vitro studies to determine the distribution of two macromolecular components typically present in purulent sputum, bacterial alginate and neutrophil-derived DNA. Sputum samples were obtained from hospitalized CF patients. DNA and alginate were disrupted, respectively, by the in vitro additions of human recombinant deoxyribonuclease I (rhDNase) or alginate lyase prepared from a mucoid strain of Pseudomonas aeruginosa. N-acetyl-L-cysteine (acetylcysteine) was similarly used to collapse the mucin matrix of these samples for comparison. Using a centrifugation-based rheological method known as the compaction assay, a greater maximal response was observed for rhDNase compared to alginate lyase treatment. A simultaneous addition of these enzymes to purulent sputum produced an additive compaction response. Electron microscopy was used to identify alginate and DNA components within the mucin matrix of sputa and to evaluate changes following treatment with high concentrations of alginate lyase or rhDNase. DNA was more widely distributed throughout purulent samples than alginate. Differences in the distribution of DNA and alginate may explain, at least in part, the larger compaction response to rhDNase versus alginate lyase treatment. An improved understanding of DNA and alginate distribution within purulent CF sputum may lead to improvements in drug and vector delivery to airway epithelial cells.
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PMID:Distribution of DNA and alginate in purulent cystic fibrosis sputum: implications to pulmonary targeting strategies. 901 Aug 13

Sputum analysis is a useful technique for the study of airway inflammation. In asthma, dithiothreitol (DTT) is used to disperse cells from surrounding mucus; however, the applicability of these processing methods to cystic fibrosis (CF) sputum is unknown. In order to compare two methods for processing sputum of patients with CF, sputum was obtained from 11 subjects with CF (8 female, aged 9-21 years). The sample was split into 2 portions and sputum dispersal using DTT was compared with an enzyme mixture (E) of deoxyribonuclease, hyaluronidase, and galactosidase. Outcomes assessed were sample quality, cell viability (percent cells excluding trypan blue), total cell count (TCC), neutrophil count, and elastase immunoreactivity (percent cells positive). Sample quality (enzymes vs. DTT, 8.3 +/- 0.3 vs 7.6 +/- 0.4, mean +/- SEM) and cell viability (enzymes vs. DTT, 75.0% vs. 68.0%, median) were similar for both methods. Sputum total cell count (20.5 x 10(6)/ml vs. 12.0 x 10(6)/ml, median; P = 0.01) and neutrophil count (13.4 x 10(6)/ml vs. 5.5 > 10(6)/ml, median; P = 0.02) were significantly higher with E. Elastase immunoreactivity was lost after processing with E (19.0% vs. 39.5%, median; P = 0.04). When purified peripheral blood neutrophils were incubated with DTT and E, there was no reduction in neutrophil viability, suggesting that the reduced neutrophil number in CF sputum was not due to a toxic effect of DTT but rather incomplete dispersal. We conclude that published sputum processing methods for asthma using DTT give false results when applied to CF sputum, which should be processed using an enzyme mixture.
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PMID:Comparison of sputum processing techniques in cystic fibrosis. 901 74

Aerosol therapy is one of the mainstays of treatment, together with regular physiotherapy, in patients with cystic fibrosis. Inhalation can contribute to hydration of the epithelial lining fluid as well as delivering different drugs directly to the lungs. Topically administered antibiotics can protect the lungs from Pseudomonas infection, recombinant DNase, amiloride and beta-agonists can have a positive effect on the mucociliary clearance, and steroid inhalations can reduce inflammation. Therefore, all these drugs are part of a comprehensive treatment strategy contributing to improvement in lung function and quality of life. Gene therapy and pharmacological correction of the chloride channel defect are perspectives for the future. Aerosol therapy, however, is somewhat cumbersome and requires strict patient education.
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PMID:Aerosol therapy in patients with cystic fibrosis. 904 84

The therapeutic significance of recombinant human DNase I in treating the patients with cystic fibrosis has risen our interests in identifying other human DNase I-like enzymes to study their biological significance. Here we described our work of cloning and characterization of a novel gene, which encodes a human protein homologous to human DNase I. A full length cDNA clone of this gene consists of 1290 bp, encoding a polypeptide of 306 amino acids. The deduced amino acid sequence of this novel human DNase (nhDNase) is 45% identical to that of human DNase I. Among sixteen human tissues examined by Northern Blot, high level expression of nhDNase was found in human liver and spleen. Recombinant protein of nhDNase was produced in a Baculovirus expression system and purified by chromatography and reverse-phase HPLC. Purified recombinant nhDNase migrated as a single band of about 33 kD molecular weight analyzed by SDS-PAGE. The DNase activity of nhDNase was demonstrated by assay of hydrolysis of S.S.DNA. Its activity was dependent upon the presence of divalent metal irons, calcium and magnesium. However, unlike bovine pancreas DNase I, nhDNase was not inhibited by G-actin of bovine muscle, which indicates the physiological significance of this enzyme in clinical implication.
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PMID:Cloning and characterization of a novel human DNase. 907 Mar 8

Human deoxyribonuclease I (DNase I), an enzyme used to treat cystic fibrosis patients, has been engineered to more effectively degrade double-stranded DNA to lower molecular weight fragments by altering its functional mechanism from the native single-stranded nicking pathway to a much more efficient one which results in increased double-stranded scission. By introducing positively charged amino acids at DNase I positions that can interact favorably with the proximal negatively charged phosphate groups of the DNA, we have created a hyperactive variant with approximately 35-fold higher DNA-degrading activity relative to wild type. This enhancement can be attributed to both a decrease in Km and an increase in Vmax. Furthermore, unlike wild-type DNase I, the hyperactive variants are no longer inhibited by physiological saline. Replacement of the same positions with negatively charged amino acids greatly reduced DNA cleavage activity, consistent with a repulsive effect with the neighboring DNA phosphates. In addition, these variants displayed similar activities toward a small synthetic substrate, p-nitrophenyl phenylphosphonate, suggesting that the difference in DNA cleavage activity is due to the interaction of the engineered charged residues with the DNA phosphate backbone rather than any change in catalytic machinery. Finally, experiments involving the repair of DNase I digested DNA with T4 DNA ligase and the Klenow fragment of DNA polymerase I suggest that single-stranded gaps are introduced by the hyperactive variants. Thus, the increased functional activity of the hyperactive variants may be explained in part by a shift toward a processive DNA nicking mechanism, which leads to a higher frequency of double-stranded breaks.
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PMID:Engineering hyperactive variants of human deoxyribonuclease I by altering its functional mechanism. 918 42

Increasingly, proteins are delivered to the respiratory tract as an aerosol, and clinical efficacy is dependent on optimal delivery of the protein in an intact form. The object of this study was to compare the in vivo and in vitro results of two aerosol delivery systems for the aerosolization of recombinant human deoxyribonuclease I (rhDNase) in patients with cystic fibrosis (CF). Patients with CF who were to be initiated on rhDNase were randomized either to the Hudson nebulizer and Pulmo-Aide compressor or to the Sidestream nebulizer driven by the CR50 air compressor. An in vitro study was performed in six sets of the two aerosol delivery systems. One hundred and seventy three patients were randomized in this open study, where rhDNase was administered for 7 days. Improvements in pulmonary function were observed in both groups following 1 week of therapy with rhDNase. Changes in the Sidestream/CR50 and Hudson/Pulmo-Aide groups, respectively, were: 16 and 11% for forced expiratory volume in one second (p=0.14); 12 and 10% for forced vital capacity (p=0.70); and 14 and 7% for forced expiratory flow at 25-75% of expiration (FEF(25-75)) (p=0.18). A greater proportion of patients in the Sidestream/CR50 group (58%) had a >10% response in FEF(25-75) compared to the Hudson/Pulmo-Aide group (42%; p=0.03). The Sidestream nebulizer had a faster nebulization rate (p<0.05), lower mass median diameter for the aerosol mass produced (p<0.001), higher percentage of particles in the respirable range (p<0.001) and greater respirable output (p<0.005), compared to the Hudson nebulizer. The Sidestream/CR50 combination is a quicker, more efficient system in vitro than the Hudson/Pulmo-Aide combination, whereas the in vivo study only suggested a difference. Clinically, the two systems have similar efficacy.
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PMID:An evaluation of two aerosol delivery systems for rhDNase. 919 26

Treatment with recombinant human deoxyribonuclease I (rhDNase) is currently used as therapy for cystic fibrosis (CF) lung disease. Hypertonic saline (HS) acts as an expectorant promoting mucus secretion and augmenting the volume of sputum. We evaluated the individual and combined effects of HS and rhDNase in vitro on the viscoelasticity of CF sputum. Sputum samples were collected from nine CF patients to use for in vitro testing. Aliquots of CF sputum (0.20 to 0.40 g) were subjected to the following protocols: (1) negative control sample without any treatment; (2) positive control sample, adding 10% volume of normal saline (0.9% NaCl); (3) application of hypertonic saline (HS-3% NaCl); (4) combining approximately 100 nM concentration of rhDNase with protocols 2 and 3. The samples in protocols 2 through 4 were incubated for 30 min at 37 degrees C. For each protocol, CF sputum was analyzed at baseline and at 30 min for spinnability by filancemeter and viscoelasticity by magnetic microrheometry. Spinnability decreased for the sputum samples that were treated with rhDNase, in combination with either HS or normal saline. Treatment with HS alone and combined treatment with rhDNase and HS decreased log G* (the principal viscoelasticity index) to the same degree. Saline alone and rhDNase in normal saline both increased the predicted cough clearability of the sputum; however, the combined treatment with rhDNase and hypertonic saline had the best overall effect on cough clearability. The change in predicted mucociliary clearability, although greatest after HS, was not significant. These in vitro results suggest that combined treatment with rhDNase and HS should be evaluated further as a potential mucotropic approach to augment the clearance of purulent sputum in CF lung disease.
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PMID:Rheology of cystic fibrosis sputum after in vitro treatment with hypertonic saline alone and in combination with recombinant human deoxyribonuclease I. 923 Jul 43

DNases are DNA hydrolyzing enzymes. The well-characterized bovine pancreatic DNase I, the first DNase discovered, is a model DNase for studying the structure-function relationships of the DNase I type enzymes. The Epstein-Barr virus produces a DNase with an unknown biologic function other than degrading DNA, and this viral DNase has been used as an Epstein-Barr viral marker. Human DNase I exhibits polymorphism that can be used for forensic identification and for correlation with certain diseases. Variations in serum DNase activities have been implicated as the result of disease states and measurements of DNase activities are often used for diagnosis and prognosis. Recombinant human DNase I has been administered in cystic fibrosis patients to improve mucociliary clearance and pulmonary function. Thus, although the primary function of DNase is to degrade DNA, there are many reports of its clinical applications.
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PMID:Deoxyribonuclease I and its clinical applications. 926 51


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