Purpose: To examine the in vitro effects of subretinal fluid (SRF) from patients with retinal detachment on extracellular matrix turnover. Methods: Matrix metalloproteinase (MMP) activity was explored by radiolabeled substrate degradation and zymography. Human lung fibroblasts were used to analyze SRF effects on collagen synthesis and cell proliferation. Transforming growth factor-β₂ (TGF-β₂) concentration was determined in SRF samples by a quantitative sandwich enzyme immunoassay. Results: MMP-2 and MMP-9 gelatinolytic activity was observed in all SRF samples. Collagenase activity was not detected in SRF from patients with holes and recurrent retinal detachment. All SRF samples stimulated fibroblast proliferation and collagen synthesis but SRF samples from recurrent retinal detachment patients with previous retinal tears had the largest effect with the largest TGF-β₂ concentration. Conclusions: The gelatinolytic activity found in all SRF samples might be associated with the retinal detachment process. Low collagenase activity with an increase in collagen synthesis could indicate a risk factor to the development of proliferative vitreoretinopathy.

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Our aim was to assess the usefulness of measuring the percentage of free prostate specific antigen (PSA) in serum in relation to reducing the number of prostate biopsies in men with benign prostate examinations and serum PSA levels between 4 and 10 ng/ml. The percentage of free PSA (Immulite) in serum was analyzed prospectively in 500 men, all of whom underwent ultrasound-guided sextant prostate biopsies. Cancer was detected in 21.4% (107/500) of the patients. Using a free PSA cutoff of < or = 23% as a criterion for performing prostate biopsy would have detected 94.4% of cancers, avoided 18.8% of benign biopsies and yielded a positive predictive value of 25.3%. The percentage of free PSA increased with prostate volume. Mean total PSA and mean free percent PSA values increased as patient age increased, influencing the calculation of cutoff values, sensitivity and specificity. PSA density had a sensitivity and specificity not significantly different than the percentage of free PSA. Measurement of the percentage of free serum PSA improves the specificity of prostate cancer detection in patients with elevated total serum PSA levels and benign prostate examinations.

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