| Autor: |
BRAGA, F. J.H.N., MANÇO, J. C., SOUZA, J. F., FERRIOLI, E., ANDRADE, J. DE, IAZIGI, N. |
| Zdroj: |
Nuclear Medicine Communications; November 1996, Vol. 17 Issue: 11 p971-974, 4p |
| Abstrakt: |
Age is known to reduce the efficacy of body organs and systems, even in the absence of disease. The alveolar-capillary clearance (ACC) rate is representative of the alveolar-capillary barrier's functional state. We studied 29 healthy non-smokers, who were selected after clinical and radiographic evaluation. The patients were divided into three groups based on age: Group I, ≤ 30 years (n= 10); Group II, 31–55 years (n= 9); Group III, ≥ 56 years (n= 10). Each patient inhaled 750 MBq 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) aerosol generated by a Venticis nebulizer (particles with a mean diameter of 1.1 (μm) for 5 min. Forty frames of 30 s duration each were acquired and the ACC rates for the right and left lungs determined using a computer program. The mean ACC rates for the three groups were as follows: Group I, 1.31 min-1; Group II, 1.08 min-1; Group III, 0.76 min-1. The differences between Groups I and III (P< 0.001) and Groups II and III (P= 0.03) were shown to be significant. There was no significant difference between Groups I and II. Possible explanations for an age-related reduction in ACC rates include a reduction in the internal alveolar surface, the closure of the small airways, a reduction in the lung blood capillaries and a reduction in cardiac output. We conclude that there appears to be an age-related reduction in ACC rates in healthy non-smokers, even in the absence of clinically and radiographically detectable lung disease. However, larger studies are required. |
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