migration. More than 90% of completed pregnancies produce viable infants, and 
CF women are generally able to breast-feed infants normally. 
IIA.4. Treatment 
The major objectives of therapy for CF are to promote clearance of 
secretions and control infection in the lung, provide adequate nutrition, and prevent 
intestinal obstruction. 
II.A.4.a. Lung Disease: 
At present, the techniques for clearing pulmonary secretions are a 
combination of breathing exercises and chest percussion. A number of 
pharmacologic agents for increasing mucus clearance are being tested. N-acetyl- 
cysteine has not been shown to have clinically significant effects on mucus clearance 
and/or lung function. However, agents that degrade the high concentrations of 
DNA in CF sputum, e.g., human recombinant DNAse, appear to be effective in 
decreasing sputum viscosity and increasing airflow during short-term administration 
(26). Experimental drugs aimed at restoring salt and water content of secretions, 
e.g., amiloride (27) and triphosphate nucleotides (28), appear promising. 
More than 95% of CF patients die of complications resulting from lung 
infection. Antibiotics are the principal agents available for treating lung infection, 
and their use should be guided by sputum culture results. Early intervention with 
antibiotics is useful, and long courses of treatment are the rule. Because of 
1 increased total body clearance and volume of distribution of antibiotics in CF 
patients, the required doses are higher for CF patients than for non-CF patients with 
similar chest infections. 
IIA.4.b. Gastrointestinal Disease: 
Maintenance of adequate nutrition is critical for the health of the CF patient. 
Most ( > 90%) of CF patients benefit from pancreatic enzyme replacement. 
Capsules generally contain between 4,000-24,000 units of lipase. The dose of 
enzymes should be adjusted on the basis of weight gain, abdominal symptomatology, 
and character of stools. Replacement of fat-soluble vitamins is also required. 
Hyperglycemia most often becomes manifest in the adult. Principles for treating 
other causes of non-ketotic hyperglycemia should be employed. 
For treatment of acute obstruction due to meconium ileus equivalent, 
megalodiatrizoate or other hypertonic radiocontrast materials delivered by enema 
to the terminal ileum are utilized. For control of symptoms, adjustment of 
pancreatic enzymes and the supplementation of intake by salt solutions containing 
osmotically active agents, e.g., propyleneglycol, are utilized. Hepatic and gall 
bladder complications are treated as for non-CF patients. End-stage liver disease 
can be treated by transplantation, which has a two-year survival rate exceeding 50%. 
II.B. Gene therapy for CF lung disease 
1I.B.1. General 
The concept of ’gene therapy’ is potentially applicable to the treatment of 
cystic fibrosis lung disease. The basic premise, based on the observation that 
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