Tonic protein kinase A activity maintains inactive beta2 integrins in unstimulated neutrophils by reducing myosin light-chain phosphorylation: role of myosin light-chain kinase and Rho kinase.

Activation of beta2 integrins is necessary for neutrophil adhesion and full activation of neutrophil effector functions. We demonstrated previously that inhibition of protein kinase A (PKA) activity in quiescent neutrophils is sufficient to increase beta2-integrin cell surface expression, affinity, and adhesion. Thus, a tonic level of PKA activity prevents inappropriate activation of beta2 integrins in unstimulated neutrophils.

Randomized, controlled study of inhaled fluticasone propionate, oral administration of prednisone, and environmental management of horses with recurrent airway obstruction.

Objective: To determine whether administration of glucocorticoids provides additional benefits to environmental management of horses with recurrent airway obstruction (RAO).

Animals: 28 horses with RAO.

Procedure: Horses were classified as having mild, moderate, or severe RAO.

The effects of cAMP modulation upon the adhesion and respiratory burst activity of immune complex-stimulated equine neutrophils.

Toxic products such as reactive oxygen intermediates released by activated polymorphonuclear neutrophil (PMN) have an important role in the pathophysiology of diseases associated with the deposition of immune complexes (IC) in tissues. IC-induced activation of PMN requires adhesion mediated by integrin adhesion receptors. Of the integrins expressed on PMN, the beta(2) family has been found to be of particular importance for activation of PMN by IC.