molecules/reaction (panel A). However, when the initial reaction products were used as a 
template for another 35 cycles of amplification using nested primers, the sensitivity was 
improved to 1 viral molecule/reaction (panel B). DNA will be isolated from a five percent of 
each viral stock and subjected to the PCR analysis. Five percent of a 2 ml viral stock should 
yield 2-20 mg of DNA which can be analyzed in 4 to 40 reaction tubes. 
V. Overall Assessment of Risks versus Benefits 
VA Risks to human subjects 
V.A.1 Blood draws. 
a) Localized hematoma at the puncture site - appropriate pressure will be applied to the 
puncture site to prevent this common complication; Vaso-vagal faint - patients will be asked to 
report any symptoms of lightheadedness or circomoral tingling which may precede a vaso-vagal 
episode; those individuals experiencing such symptoms will be kept in a recumbent position 
until this temporary reaction abates, b) If the above precautions are taken, the potential risk to 
blood donors is negligible. 
V.A.2 Bronchoscopy. 
A minor discomfort that is associated with the urge to cough occurs when saline solution is 
injected. Pneumothorax resulting from rupture of alveolar tissues allowing air to enter the 
pleural space, causing partial collapse of the lung. This complication, though potentially 
serious, occurs rarely when the procedure is performed by experienced personnel. 
Pneumothorax occurs in 0.5-2% of cases, although only 1/3 to 1/2 of bronchoscopies 
associated with pneumothoraces require placement of a thoracostomy tube. In the remaining 
cases spontaneous resolution of the pneumothorax occurs and no intervention is necessary. Our 
experience during a 2 year study in 1988-1990 at the University of Michigan hospital has 
corroborated a low incidence of pneumothorax. During those years we have performed 773 
bronchoscopies; 6 pneumothoraces not requiring a thoracostomy tube have occurred and 6 
pneumothoraces requiring a thoracostomy tube have been reported for a total incidence of 1 .5%. 
Bronchoscopy is performed in a hospital setting with all provisions for emergency treatment if 
the need should arise. Mucosal inflammation can occur when the bronchoscope is wedged into the 
bronchus. No clinically important consequences have occurred. Bleeding can occur following 
transbronchial biopsies. The incidence of moderate or severe bleeding following transbronchial 
biopsy is <1% when normal hemostasis is present. Serious bleeding resulting in the need for 
transfusion, acute respiratory decompensation or fatality have been exceedingly rare and have 
usually been confined to patients with underlying coagulopathy or in the setting of hematologic 
malignancies with thrombocytopenia. 4 of 773 bronchoscopies resulted in bleeding which was 
serious enough to require hospital admission. In no instances was transfusion required or did 
respiratory decompensation occur. An important question relates to the relevance of our 
experience with bronchoscopy in the general population to bronchoscopy in a cystic fibrosis 
population. Dr. Robert Fick at the University of Iowa (now at Genentech) has performed 
bronchoscopy on over 50 cystic fibrosis patients. He found no greater risk of major 
complications as compared to similar procedures performed on 100 non cystic fibrosis 
patients. He did see a higher incidence of postprocedure fever (incidence approximately 20%) 
and infiltrate (5%) in the cystic fibrosis group. Review of the literature indicates that 
bronchoscopy is a generally accepted investigational procedure in protocols involving patients 
with cystic fibrosis. We have located 10 published studies form 6 independent groups in which 
investigational bronchoscopy was used in a total of 105 patients (Wood et al., 1975; Fick et al., 
Recombinant DNA Research, Volume 16 
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