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)

Cystic fibrosis (CF) is caused by mutation in the gene for the CF transmembrane conductance regulator which leads to massive, abnormally viscous, purulent sputum, chronic destructive endobronchitis and early death. Purified recombinant human (rh) DNase can digest extracellular DNA and its inhalation in these patients significantly improves lung function. To evaluate the poorly understood mechanisms, saliva protected sputum from patients treated with and without rhDNase were evaluated. Therapy with rhDNase resulted in a soluble sputum fraction that had a higher percentage of phosphatidylethanolamine, a phospholipid present mainly in cellular membranes, a much lower percentage of phosphatidylcholine, but a higher surface activity. The rigidity was significantly lower and the ratio of viscosity in proportion to elasticity increased. All these data are consistent with an increased clearability of the sputum by coughing, but not by mucociliary activity. Thus the interaction of inhaled rhDNase with the purulent mucus and the endobronchial inflammatory processes may induce changes that result in rheological properties favoring clearance of sputum by cough.
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PMID:Recombinant human DNase (rhDNase) influences phospholipid composition, surface activity, rheology and consecutively clearance indices of cystic fibrosis sputum. 934 29

To identify factors influencing lung dose of aerosolized recombinant human deoxyribonuclease (rhDNase I), we used gamma camera and filter techniques to measure deposition in 15 clinically stable patients with cystic fibrosis (CF) (five males and 10 females, age 6-31 yr, mean 16.9) who were on chronic daily therapy. Total and regional deposition were correlated with breathing pattern, pulmonary function, demographic factors, and disease severity. In addition, the effects of each patient's measured lung dose on pulmonary function was estimated by stopping the drug and observing changes in spirometry over a 2-wk follow-up period. After discontinuance of the drug, all patients reported worsening of dyspnea and difficulty producing sputum. There was a significant decrease in FEV1 (% predicted, mean +/- SE, 86.9% +/- 5.57 to 77.8% +/- 5.73, p < 0.005), but all patients completed the study. In some patients, as much as 48% of the deposited aerosol was found in the pharynx (range 0.0 to 0.30 mg, mean 0.089 mg +/- 0.029), and pharyngeal deposition correlated negatively with tidal volume (r = -0.696, p < 0.006) and age (r = -0.743, p < 0.005). For the lungs, deposition ranged between 0.16 mg and 0.78 mg of the 2.5 mg nebulizer dose (mean 0.47 +/- 0.04 mg) and correlated negatively with FEV1 (% predicted, r = -0.611, p = 0.0152). However, the spirometric decrements following cessation of therapy did not correlate with the lung dose of the drug. Analysis of regional deposition within the lungs indicated a wide range of distribution between central and peripheral zones. In conclusion, the deposition pattern of rhDNase I aerosols in patients with CF is largely influenced by respiratory physiology, which itself depends upon age and severity of lung disease. As the patients grow there is a decrease in upper airway deposition and more particles are presented to the lungs where those patients with more airways disease have enhanced pulmonary deposition. Upper airway deposition of rhDNase I is significant, especially in younger patients, and may be related to laryngeal side effects.
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PMID:RhDNase I aerosol deposition and related factors in cystic fibrosis. 937 91

We report a case of twins with cystic fibrosis. The twins are of mixed parentage, having a Japanese mother and a German father. One case presented with meconium ileus as a neonate. The other twin was relatively healthy until the age of 6, when she was first hospitalized with a diagnosis of pulmonary aspergillosis. They have been receiving standard therapies in the United States, including digestive enzymes, vitamins, and periodic antibiotics. At the age of 19 both patients received home intravenous antibiotic therapy, and began to use an inhaled DNase at the age of 20. When the patients were 19 they were screened for the common mutations causing cystic fibrosis, and the delta F508 CFTR mutation was identified. We analyzed their CFTR genes, as well as those of their Japanese mother and grandmother. Missense mutations at exon 7 (R347H) and exon 16 were found (D979A) in the twins and in their Japanese mother.
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PMID:[Two cases of cystic fibrosis in Japanese/German twins]. 949 56

Aerosolized recombinant human DNase (dornase alfa) reduces mucus viscoelasticity in vitro and improves pulmonary function in patients with cystic fibrosis (CF). We postulated that if dornase alfa could be delivered more peripherally to small airways in the lung in the form of smaller aerosol droplets in patients with early airway obstruction, the increase in pulmonary function from baseline might be improved. CF patients (n = 749) with mild lung disease (baseline forced vital capacity > or = 70% predicted) were randomly assigned to receive dornase alfa 2.5 mg daily for 2 weeks by one of two nebulizer systems: 1) the Medic-Aid Durable SideStream nebulizer powered by the MobilAire Compressor (SS/MA) producing a droplet size with a mass median aerodynamic diameter (MMAD) of 2.1 microm; or 2) the Hudson T Up-draft nebulizer with a DeVilbiss Pulmo-Aide compressor (HT/PA) with an MMAD of 4.9 microm. Spirometry was performed at baseline and following 14 days of treatment. Dornase alfa delivered by both nebulizer systems produced small but statistically significant improvements in pulmonary function compared with baseline. There was a trend (P = 0.06) toward greater improvement in forced expiratory flow in 1 s in the SS/MA group (4.3%) compared with the HT/PA group (2.5%). These results indicate that the short-term spirometric response to dornase alfa is influenced in part by the physical characteristics of the aerosol in patients with mild lung disease. We speculate that this may be true for other therapeutic aerosols, and it appears that localization of disease in the lung plays a role in the response to inhaled agents.
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PMID:Effect of smaller droplet size of dornase alfa on lung function in mild cystic fibrosis. Dornase Alfa Nebulizer Group. 951 89

Trials of gene transfer for cystic fibrosis (CF) are currently underway. However, direct application to the airways may be impeded by the presence of airway secretions. We have therefore assessed the effect of CF sputum on the expression of the reporter gene beta-galactosidase complexed with the cationic liposome DC-Chol/DOPE in a number of cell lines in vitro. Transfection was markedly inhibited in the presence of sputum; the effect was concentration dependent and was only partially ameliorated by removal of sputum with phosphate-buffered saline (PBS) washing before gene transfer. However, treatment of the sputum-covered cells with recombinant human DNase (rhDNase, 50 micrograms/ml) but not with N-acetylcysteine, Nacystelyn, lysine (all 20 mM) or recombinant alginase (0.5 U/ml) significantly (P < 0.005) improved gene transfer. Adenovirus-mediated gene transfer efficiency in the presence of sputum was similarly inhibited, and again, treatment with rhDNase before transfection significantly improved gene transfer (P < 0.005). Transfection of Cos 7 cells in the presence of exogenous genomic DNA alone demonstrated similar inhibition to that observed with sputum and was also ameliorated by pre-treatment of DNA-covered cells with rhDNase. In a separate series of experiments performed in the absence of added sputum or genomic DNA, increasing concentrations of rhDNase resulted in a concentration-related decline in transfection efficiency. However, even at the highest concentration (500 micrograms/ml of rhDNase), transfection efficiency remained more than 50% of control. Thus, pre-treatment of CF airways with rhDNase may be appropriate before liposome or adenovirus-mediated gene therapy.
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PMID:The effect of mucolytic agents on gene transfer across a CF sputum barrier in vitro. 953 69

Human deoxyribonuclease I (DNase I), an enzyme used to treat cystic fibrosis patients, has been systematically analyzed by site-directed mutagenesis of residues at the DNA binding interface. Crystal structures of bovine DNase I complexed with two different oligonucleotides have implicated the participation of over 20 amino acids in catalysis or DNA recognition. These residues have been classified into four groups based on the characterization of over 80 human DNase I variants. Mutations at any of the four catalytic amino acids His 134, His 252, Glu 78, and Asp 212 drastically reduced the hydrolytic activity of DNase I. Replacing the three putative divalent metal ion-coordinating residues Glu 39, Asp 168, or Asp 251 led to inactive variants. Amino acids Gln 9, Arg 41, Tyr 76, Arg 111, Asn 170, Tyr 175, and Tyr 211 were also critical for activity, presumably because of their close proximity to the active site, while more peripheral DNA interactions stemming from 13 other positions were of minimal significance. The relative importance of these 27 positions is consistent with evolutionary relationships among DNase I across different species, DNase I-like proteins, and bacterial sphingomyelinases, suggesting a fingerprint for a family of DNase I-like proteins. Furthermore, we found no evidence for a second active site that had been previously implicated in Mn2+-dependent DNA degradation. Finally, we correlated our mutational analysis of human DNase I to that of bovine DNase I with respect to their specific activity and dependence on divalent metal ions.
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PMID:Mutational analysis of human DNase I at the DNA binding interface: implications for DNA recognition, catalysis, and metal ion dependence. 954 95

Recombinant human deoxyribonuclease (rhDNase) has been shown to reduce sputum viscoelasticity and to improve lung function in patients with cystic fibrosis (CF). The aim of this study was to determine whether airway inflammation would decrease after administration of rhDNase. Twenty patients with CF and chronic suppurative lung disease inhaled 2.5 mg of rhDNase daily for 1 month. Before and after the 1-month trial, lung function was measured and sputum was obtained, either after spontaneous expectoration or after sputum induction with hypertonic saline. Sputum total cell and differential counts were measured using techniques previously described. The mean age of the patients was 16.8 years (range, 6.7-27.5). After 1 month of rhDNase, mean FEV1 increased from a baseline of 62.3% predicted to 70.8% (P= 0.02, paired t test); and FVC increased from 74.4% to 83.9% predicted (P=0.007). No significant differences were found in sputum cytology before or after rhDNase (median total cell counts 16.0 x 10(6)/ml vs. 19.3 x 10(6)/ml, P=0.68). Thirteen patients had a 10% or greater increase in FEV1 after rhDNase (responders). Initial lung function was less in responders than in nonresponders (53.5% vs. 78.6%, P=0.007). There was no significant change in total cell count and neutrophil count after rhDNase in either responders or nonresponders. We conclude that airway inflammation, as measured by total cell counts in sputum, was a prominent feature in cystic fibrosis, and neutrophils were the dominant inflammatory cells. Although the administration of rhDNase resulted in significant improvements in FEV1, there was no evidence of accompanying changes in airway inflammation.
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PMID:Airway inflammation after treatment with aerosolized deoxyribonuclease in cystic fibrosis. 972 59

Although dornase alpha (recombinant human DNase) can thin the viscid pulmonary secretions of cystic fibrosis (CF), clinical trials in groups of unselected patients have shown only modest average improvements in pulmonary function. The product is very expensive, so in conjunction with purchasers we designed selection criteria and a protocol for a 2-week trial to target CF individuals who might gain most benefit. Treatment was to be continued in those showing > or = 10% improvement in pulmonary function. Those who had a trial of dornase alpha were followed up for 2 years. Of 25 patients who had a 2-week trial of dornase alpha, 17 met the criteria for continuation (average gain in forced expiratory volume 37%). The 11 of these who were still alive at 2 years had a greater initial average FEV1 improvement than those who had died (45% versus 22%), and still had an average improvement of 31% at 2 years. The 8 patients who did not meet the criteria for continuation were older and had required fewer intravenous antibiotic courses. All these were alive at 2 years with unchanged clinical indices. This method of selection for dornase alpha treatment allows targeting to those who gain most benefit without disadvantaging the remaining patients. Furthermore, production of such guidelines in conjunction with purchasers obviates funding difficulties and allows rational prescribing.
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PMID:Targeting of dornase alpha therapy in adult cystic fibrosis. 977 94

Cystic fibrosis is characterized by the accumulation of thick viscous purulent secretions. Recombinant human deoxyribonuclease I (rhDNase) breaks down extracellular DNA, which contributes to the increased viscosity of sputum. A multinational, open-label study was conducted in 974 cystic fibrosis patients with moderate lung disease [forced vital capacity (FVC) 40-70% of predicted values] to examine the safety and efficacy of aerosolized rhDNase, 2.5 mg, once daily over a period of at least 12 weeks. Patients were assessed under conditions reflecting routine clinical practice. During rhDNase therapy, at least one respiratory tract infection (RTI) requiring intravenous antibiotics was experienced by 29.5% of patients. Forced expiratory volume in 1 second (FEV1) and FVC were significantly improved from baseline by a mean of 10.5% and 7.2%, respectively. Voice alteration and pharyngitis were the most frequent rhDNase-related adverse events, but only 2% of all patients discontinued treatment due to adverse events. The results obtained were similar to a subanalysis of data from the first 3 months of a placebo-controlled U.S. study. The patients in the present study had a similar frequency of RTIs and improvement in pulmonary function, and reported fewer rhDNase-related and cystic fibrosis-related adverse events than patients in the U.S. study. We conclude that administration of rhDNase is safe, well tolerated, and effective under conditions reflecting routine clinical practice in patients with cystic fibrosis and moderate lung disease.
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PMID:Multicenter, open-label study of recombinant human DNase in cystic fibrosis patients with moderate lung disease. DNase International Study Group. 977 9

The purpose of this study was to assess the delivery to the lungs and the short-term safety of recombinant human deoxyribonuclease (rhDNase, Pulmozyme) in children with cystic fibrosis younger than 5 years of age compared with older children. Patients between the ages of 3 months and 10 years had bronchoscopic examination with bronchoalveolar lavage (BAL) after administration of an aerosol dose of 2.5 mg of rhDNase. After recovery from the procedure, patients were discharged home for an additional 13 days of rhDNase therapy. During this time adverse events were recorded to assess short-term safety. A total of 98 patients were enrolled, 65 (66%) aged 3 months to 5 years and 33 (34%) aged 5 years to 10 years. Deoxyribonuclease concentrations in BAL fluid were variable (interquartile range, 752 to 3943 micrograms/mL epithelial lining fluid [ELF]) and did not depend on patient age, weight, or height or differ when delivered through a mouthpiece or mask. The median value for the BAL DNA concentration in the younger group was 432 micrograms/mL ELF compared with 703 micrograms/mL ELF in the older patients. This study demonstrates the value of bronchoscopy and BAL for assessing nebulized medication delivery in young children and shows that aerosolized medications can be delivered to and are present in comparable amounts in the lower airways of younger and older children. Exposure to rhDNase appears to be safe over 2 weeks in infants and young children with cystic fibrosis.
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PMID:Aerosol delivery and safety of recombinant human deoxyribonuclease in young children with cystic fibrosis: a bronchoscopic study. Pulmozyme Pediatric Broncoscopy Study Group. 978 85


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