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 the commonest, fatal, autosomal recessive disorder and is associated with lung sepsis, pancreatic failure and elevated sweat electrolytes. The CF gene on chromosome 7 encodes a protein identified as CF transmembrane conductance regulator (CFTR) which regulates chloride ion transport in epithelial cell membranes. Almost 100 mutations have been identified in this gene which cause defective chloride-channel control. Recently, this abnormality has been reversed in affected CF cells in vitro by retrovirus-mediated transfer of a normal gene. Fifty years ago, most cases died in childhood, but now up to 80% reach adulthood. Chronic lung sepsis is the principal cause of death, and intensive antibiotic therapy with chest physiotherapy is used to control this. Advanced lung disease can be successfully treated by heart-lung transplantation. Nebulised recombinant DNase and antineutrophil elastase agents such as alpha-1-antitrypsin and secretory leucoprotease inhibitor are potentially promising new therapies. Pancreatic insufficiency is managed by high-calorie diets and enteric coated enzyme supplements. Other prominent gastrointestinal complications include meconium ileus equivalent, biliary cirrhosis and cholelithiasis. Specially dedicated CF centres have led to improved survival rates and allow experienced staff to treat the many complications of CF while promoting research in this multisystem disorder.
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PMID:Cystic fibrosis in adolescents and adults. The coming of age of cystic fibrosis. 155 Dec 44

Antibiotics bind to whole cystic fibrosis sputum, however, the composition of sputum varies from one patient to another, making the interpretation of binding studies difficult. This problem has been examined by standardizing the macromolecule concentration of sputum from 13 patients suffering from cystic fibrosis, chronic bronchitis or bronchiectasis and adding amikacin to the sputum components. Also binding to fractions of sputum was studied before and after treatment with DNase or chondroitinase. These studies indicated that the degree of amikacin binding is dependent on the DNA concentration and the presence of acidic mucins.
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PMID:The binding of amikacin to macromolecules from the sputum of patients suffering from respiratory diseases. 162 90

A minor mucin glycoprotein component (HTM-2) was purified from the tracheobronchial secretions of two cystic fibrosis patients using a protocol established in our laboratory. The secretions were solubilized in 0.1 M Tris-HCl buffer (pH 7.5) containing 0.22 M potassium thiocyanate and fractionated on a Bio-Gel A-5m column, followed by digestion with DNAase, rechromatography on the same column and chromatography on hydroxyapatite which resolved the major mucin (HTM-1) from the minor mucin component (HTM-2). The mucin component HTM-2 was further purified using Superose 6 chromatography. SDS-composite gel (2% polyacrylamide + 0.5% agarose) and 6% polyacrylamide gel electrophoresis showed that the purified HTM-2 was totally free of low-molecular-weight contaminants. Equilibrium density sedimentation centrifugation of purified HTM-2 using CsCl gradients also showed the absence of proteoglycans and other low-molecular-weight proteins. Comparison of carbohydrate and amino acid compositions of the two mucin components indicated that HTM-2 was quite different from the major mucin, HTM-1, reported earlier from our laboratory (Biochemistry, 24, 7334, 1985). This suggested that HTM-2 has a different polypeptide core and is perhaps a different gene product. The effects of 6 M guanidine-HCl and different concentrations of NaCl on the molecular size of HTM-2 and its ability to form aggregates was also investigated using the technique of static light scattering. In buffer containing 6 M guanidine-HCl, HTM-2 had a weight-average molecular weight of approximately 4.5 x 10(6). However, in the presence of buffer containing 0.03, 0.10 or 0.15 M NaCl, the molecular weight of HTM-2 was estimated to be approximately 11 x 10(6). These data suggest aggregation of HTM-2 in the presence of a range of NaCl concentrations. In contrast to HTM-1, which is a more anionic glycoprotein, the apparent molecular size of HTM-2 did not decrease at the higher NaCl concentration.
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PMID:Physicochemical characterization of a minor mucin component from cystic fibrosis tracheobronchial secretions. 202 32

Respiratory distress and progressive lung destruction in cystic fibrosis can be attributed to bacterial persistence and the accumulation of viscous purulent secretions in the airways. More than 30 yr ago it was suggested that the large amounts of DNA in purulent secretions contribute to its viscosity and that bovine pancreatic DNase I could reduce the viscosity. To evaluate the potential clinical utility of recombinant human DNase I (rhDNase) in the treatment of cystic fibrosis, we have cloned, sequenced, and expressed rhDNase. Catalytic amounts of rhDNase greatly reduce the viscosity of purulent cystic fibrosis sputum, transforming it within minutes from a nonflowing viscous gel to a flowing liquid. The reduction in viscosity is associated with a decrease in size of DNA in the sputum. Inhalation of a rhDNase aerosol may be a simple direct approach that will help individuals with cystic fibrosis and other patients with pneumonia or bronchitis to clear their airways of purulent secretions.
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PMID:Recombinant human DNase I reduces the viscosity of cystic fibrosis sputum. 225 Dec 63

The major nonreduced mucus glycoproteins (mucins) from sputa of cystic fibrosis (CF) and asthmatic patients have been purified to electrophoretic homogeneity and subjected to physical and chemical characterization. The sputum specimens were solubilized in buffer containing 0.22 M KSCN and fractionated on Bio-Gel A-5m, followed by digestion with DNase, rechromatography on the same column, and chromatography on hydroxylapatite. Sodium dodecyl sulfate gel electrophoresis of purified mucins gave a single band. Carbohydrate analyses of the purified mucins showed no significant differences in the sugar components from the two mucins. However, the CF mucin contained substantially higher (11%) sulfate content than that observed for the asthmatic mucin (5.9%). Amino acid analyses indicated that the CF mucin had higher levels of serine plus threonine (35%) as compared to the asthmatic mucin (29%). In contrast, CF mucin contained a lower content of aspartate, glutamate, and glycine than that observed for the asthmatic mucin. Molecular weights of 3.8 X 10(6) and 3.5 X 10(6) were obtained for CF and asthmatic mucins, respectively, from light-scattering studies of mucins in the presence of 6 M guanidine hydrochloride. Reduction of the disulfide bonds of the two mucins did not alter their molecular weights. Liquid chromatographic studies on Sepharose CL2B showed that CF mucin forms aggregates sufficiently large to be excluded from the gel. As compared to the CF mucin, the asthmatic mucin formed fewer of these large aggregates under identical experimental conditions. Reduction and alkylation of the mucins resulted in their inability to form aggregates. The higher state of aggregation of CF mucin may influence the viscoelastic properties of the CF lung's mucus secretions.
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PMID:Comparison of physicochemical properties of purified mucus glycoproteins isolated from respiratory secretions of cystic fibrosis and asthmatic patients. 300 52

Antibiotics are known to bind to whole cystic fibrosis sputum. However, the composition of sputum varies from one patient to another, making the interpretation of binding studies difficult. This problem has been examined by standardising the macromolecule concentration of sputum from four cystic fibrosis patients and adding tobramycin or ceftazidime directly to the sputum components. Binding to mucin-rich and DNA-rich fractions of sputum was also studied before and after DNase treatment of these fractions. These studies indicated that (i) the degree of tobramycin binding is dependent on the sputum macromolecule concentration, (ii) a significant proportion of tobramycin is bound even at concentrations of 100 mg/l of drug, (iii) tobramycin binds to both the mucin rich fraction and the DNA rich fraction of sputum and (iv) ceftazidime binding to sputum is negligible. Our data indicate that there is a need to standardise sputum in antibiotic binding studies and they provide another rationale for favouring the use of ceftazidime over aminoglycosides in infectious exacerbations of cystic fibrosis caused by Pseudomonas aeruginosa.
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PMID:The binding of anti-pseudomonal antibiotics to macromolecules from cystic fibrosis sputum. 306 Apr 59

A rapid and simple in vitro method is described which measures the extent of unrecoiled solids compression when a complex biopolymer is subjected to a centrifugal force. This method, termed the compaction assay, was used to assess the response of purulent cystic fibrosis (CF) sputum samples to the addition of recombinant human deoxyribonuclease I (rhDNase). Enzyme treatment resulted in a dramatic decrease in DNA size, a redistribution of total DNA content from the pellet to supernatant, a significant decrease in that pellet volume and a decrease in elastic modulus. Sample elasticity, measured by a dynamic cone and plate viscometer, could be related to compaction assay results. These results suggest that the compaction assay may be a useful in vitro method for rapidly assessing the actions of enzymatic disruption of a complex biopolymer, such as that observed for the actions of rhDNase on purulent airway secretions.
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PMID:Compaction assay: a rapid and simple in vitro method to assess the responsiveness of a biopolymer matrix to enzymatic modification. 749 20

A broad-based approach will be required for the development of new therapies for cystic fibrosis lung disease. Recently, rapid progress has been made in identifying and testing a number of gene transfer vectors, including adenoviral vectors and liposomes. Major problems, however, have been identified with respect to the efficiency of these systems. Preliminary studies suggest that small molecules (e.g. amelioride and UTP) may normalize the clearance of secretions from the cystic fibrosis lung. The concept of recombinant protein based therapy for cystic fibrosis has now been realized with the successful application of DNase in clinical trials.
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PMID:The genetics of cystic fibrosis: a paradigm for uncovering new drug targets. 753 Oct 34

By cleaving neutrophil-derived DNA present in the infected lungs of patients with cystic fibrosis (CF), dornase alfa (recombinant human deoxyribonuclease I) reduces the adhesiveness and viscoelasticity of CF sputum. Well designed clinical studies performed in patients with CF and mild to moderate pulmonary disease [forced vital capacity (FVC) > or = 40% of predicted value] show that aerosolised dornase alfa improves lung function, achieving a 6 to 7% increase from baseline in forced expiratory volume in 1 second (FEV1) after 6 months' therapy. Improvements in general well-being and CF-related symptoms were also noted by patients. Importantly, dornase alfa reduced the relative risk of respiratory exacerbations requiring parenteral antibiotics by 22 to 34% compared with placebo. Short term studies with dornase alfa in patients with more severe pulmonary disease (FVC < 40% of predicted value) and in those with acute infectious exacerbations did not reveal any significant improvements in pulmonary function, although long term studies are required to fully determine efficacy. Voice alteration, laryngitis or rash may develop with dornase alfa therapy, although more clinical experience with the agent is required to define its tolerability profile. Anaphylaxis has not been reported with dornase alfa to date. In summary, aerosolised dornase alfa offers modest improvements in lung function and, importantly, a reduced risk of respiratory exacerbations in patients with CF and an FVC > or = 40% of the predicted value, thus representing an important adjunct agent in this patient group.
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PMID:Dornase alfa. A review of its pharmacological properties and therapeutic potential in cystic fibrosis. 753 97

Tobramycin, an aminoglycoside antibiotic, is used in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis patients. Tobramycin bioactivity, however, is antagonized by sputum. Glycoproteins (mucins) and high-molecular-weight DNA make up 2 to 3% (P. L. Masson and J. F. Heremans, p. 412-475, In M. J. Dulfano, ed., Sputum: Fundamentals and Clinical Pathology, 1973) and 3 to 10% (W. S. Chernick and G. J. Barbero, Pediatrics 24:739-745, 1959, and R. Picot, I. Das, and L. Reid, Thorax 33:235-242, 1978) of the dry weight of sputum, respectively. tobramycin binds to both mucins and DNA obtained from sputum (R. Ramphal, M. Lhermitte, M. Filliat, and P. Roussel, J. Antimicrob. Chemother. 22:483-490, 1988). In vitro, recombinant human DNase (rhDNase) hydrolyzes high-molecular-weight DNA of > 50 kb within sputum to fragments of 2 to 4 kb. Studying dialyzable tobramycin, we examined drug binding to whole sputum and to "mock sputum," which consisted of porcine gastric mucin and calf thymus DNA. We also studied the effects of rhDNase treatments of sputum, mock sputum, and calf thymus DNA on tobramycin binding. We found that treatments of sputum, mock sputum, and calf thymus DNA with rhDNase did not significantly increase the tobramycin bioactivity within the dialysates; surprisingly, sputum binding of tobramycin was increased by rhDNase. We conclude that rhDNase does not increase the bioactivity of tobramycin in sputum.
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PMID:Macromolecular mechanisms of sputum inhibition of tobramycin activity. 753 39


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