ABSTRACT
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 +/- 0.4% (P less than 0.01) and 100 +/- 0% (P less than 0.001); at each concentration, the maximal effect was reached by 20 to 25 min. Between 10(-8) and 10(-6) M H2O2, the decrease in CBF was reversible, lactate dehydrogenase (LDH) release was not significantly increased, and major morphologic lesions were not seen. At higher concentrations of H2O2, incomplete recovery of CBF (10(-5) M) or irreversible ciliostasis (10(-4) M) developed, and a significant increase in LDH and morphologic lesions were present. Catalase (2,000 U/ml) and H-7 (10(-5) M), a protein kinase inhibitor, abolished cilioinhibition produced by H2O2 at 10(-6) M and lower concentrations but not at 10(-5) M and higher concentrations. Phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator, caused a dose-dependent (10(-11) to 10(-5) M), reversible decrease in CBF; this effect was abolished by H-7. We suggest that at nonlethal concentrations, H2O2 inhibits the beat frequency of airway epithelial cilia reversibly, through the activation of second messengers, including protein kinase C. This mechanism might contribute to the previously demonstrated impairment of mucociliary clearance in airway inflammation.
Subject(s)
Hydrogen Peroxide/pharmacology , Trachea/drug effects , Animals , Catalase/pharmacology , Cilia/drug effects , Cilia/physiology , Dose-Response Relationship, Drug , L-Lactate Dehydrogenase/analysis , Second Messenger Systems , Sheep , Tetradecanoylphorbol Acetate/pharmacology , Time Factors , Trachea/enzymologyABSTRACT
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. No toxic reagents are used and, since the analysis is purely physicomathematic, the sample is not altered and can be used for additional tests.
Subject(s)
Hemoglobins/analysis , Bilirubin/blood , Humans , Myoglobin/blood , Plasma/analysis , Reference Standards , Spectrophotometry, UltravioletABSTRACT
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. Data confirming the usefulness of this technic for reliably and quantitatively separating these two substances in aqueous solution are presented. Recording derivative spectrophotometry may be useful for analyzing amniotic fluid, urine, or other biologic fluids.
