Collagen gel contraction. (A) The contractile potential of the isolated fibroblasts was monitored in collagen contraction gels over time by comparing gel areas of each time point by the initial gel areas. Each point represents the mean of each study group. (B) Contractile potential of isolated fibroblasts after 24 hours compared to the initial area. Open symbols represents fibroblasts isolated from lung explants and closed symbols fibroblasts isolated from lung biopsies. **P < 0.01.