Assessment of the antielastase activities in bronchoalveolar lavage fluid: Effect of assay buffer ionic strength
✍ Scribed by A. Felix Ofulue; Raja T. Abboud
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 745 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0009-9120
No coin nor oath required. For personal study only.
✦ Synopsis
Objective:
To evaluate the effect of assay buffer ionic strength on assessment of the antielastase activities in bronchoalveolar lavage fluid.
Method: An improved assay protocol in which elastase (in Tris-HCI buffer) is added to increasing volumes of test samples (made up to equal volume with phosphate-buffered saline) was used.
Results:
The percent NE activity inhibited by BALF decreased with increasing NaCI concentration of the buffer. Inhibition of pancreatic elastase (PE) was not affected. One hundred percent inhibition of NE by pure AA'I" and SLPI standards occurred at molar ratios of 0.91 ---0.03 for AAT-to-NE and 0.83 -+ 0.02 for SLPI-to-NE when assayed in buffer with ~<0.15 mol NaCI/L, compared to ratios of 0.99 -+ 0.0;! and 1.06 +-0.02, respectively, for assays in buffers with 0.50-1.00 mol NaCI/L (p < 0.05 for AATto-NE; p < 0.02 for SLPI-to-NE). The AAT-to-PE molar ratio at 100% inhibition of PE was not affected. Assays in buffer with ~<0.15 mol NaCI/L indicated that 86.9 --4.1% of AAT and 100.9 -+ 4,9% of SLPI in BALF were active against NE, while assays in buffer with 0.50-1.00 mol NaCI/L showed that 84.4 -+ 3.5% of hAT and 81.6 --5.9% of SLPI present were active, hAT inhibited NE and PE equally only in buffer with 0.50-1.00 mol NaCI/L. Concluelone: The results of assays of BALF antielastase activities depend on the assay buffer NaCI concentration, which may account for the conflicting reports in the literature. The buffer with 0.50-1.00 mol NaCI/L appear to be optimal for valid quantitation of anti-NE activities in BALF.