12 research outputs found
Progression of Lung Disease in Preschool Patients with Cystic Fibrosis
RATIONALE:
Implementation of intervention strategies to prevent lung damage in early cystic fibrosis (CF) requires objective outcome measures that capture and track lung disease.
OBJECTIVES:
To define the utility of the Lung Clearance Index (LCI), measured by multiple breath washout, as a means to track disease progression in preschool children with CF.
METHODS:
Children with CF between the ages of 2.5 and 6 years with a confirmed diagnosis of CF and age-matched healthy control subjects were enrolled at three North American CF centers. Multiple breath washout tests were performed at baseline, 1, 3, 6, and 12 months to mimic time points chosen in clinical care and interventional trials; spirometry was also conducted. A generalized linear mixed-effects model was used to distinguish LCI changes associated with normal growth and development (i.e., healthy children) from the progression of CF lung disease.
MEASUREMENTS AND MAIN RESULTS:
Data were collected on 156 participants with 800 LCI measurements. Although both LCI and spirometry discriminated health from disease, only the LCI identified significant deterioration of lung function in CF over time. The LCI worsened during cough episodes and pulmonary exacerbations, whereas similar symptoms in healthy children were not associated with increased LCI values.
CONCLUSIONS:
LCI is a useful marker to track early disease progression and may serve as a tool to guide therapies in young patients with CF
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Water-Resources Investigations Report 80-10
Water-quality data collected in the upper Oyster Creek drainage basin indicate that the stream has excellent water quality except for a persistently low pH. The mean concentrations of the major inorganic ions were all less than 6.0 mg/L. Mean concentrations of total nitrogen and total phosphorus were 0.15 mg/L and 0.01 mg/L, respectively. Dissolved oxygen averaged 8.7 mg/L and 81 percent saturation. Low pH levels are typical of streams draining cedar swamps. In Oyster Creek, the pH tended to decrease downstream due to chemical and biological processes. The pH levels in swamps were one-half unit or more lower than the pH levels in the adjacent stream. Sharp declines in stream pH were noted during runoff periods as the result of the mixing of poorly-buffered stream water with more highly acidic water from surrounding swamp areas. The quality of ground water within the study area was similar to the quality of stream flow, except for higher iron and ammonia-nitrogen concentrations and a higher pH range of 4.9-6.5. Precipitation represented a major source of many chemical constituents in the ground- and surface-waters of Oyster Creek basin