Mechanism of hydrogen peroxide-induced inhibition of sheep airway cilia.

To study the effect of the inflammatory mediator hydrogen peroxide (H2O2) on airway ciliary activity, we measured ciliary beat frequency (CBF) in cultured tracheal explants from sheep. Addition of H2O2 (10(-8) to 10(-4) M) produced a concentration-dependent mean (+/- SEM) decrease in CBF between 11.1 +/- 0.

Plasma hemoglobin determination by recording derivative spectrophotometry.

Recording derivative spectrophotometry (DS) is a technic for analyzing absorbance curves by measuring the derivative (slope) of those curves. The derivative is a mathematical function that enhances rapid changes of direction of a curve and suppresses slow changes. We are presenting a simple, rapid, and reproducible method for determining plasma hemoglobin concentration, even in the presence of bilirubin, myoglobin, or marked turbidity.

Separation of bilirubin from hemoglobin by recording derivative spectrophotometry.

Recording derivative spectrophotometry is a technic for resolving overlapping absorbance curves by enhancing small changes in those curves. The derivative (slope) is a function sensitive to rapid changes in the curve and will amplify those regions while damping out slowly changing portions of curves. The method presented relies on a mathematical analysis of the composite absorption curve formed by bilirubin and hemoglobin.