1. Effects of extracellular Ca2+ on phagocytosis and intracellular Ca2+ concentrations in polymorphonuclear leukocytes of postpartum dairy cows.
- Author
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Ducusin RJ, Uzuka Y, Satoh E, Otani M, Nishimura M, Tanabe S, and Sarashina T
- Subjects
- Adjuvants, Immunologic metabolism, Animals, Calcium administration & dosage, Calcium blood, Cattle, Cattle Diseases blood, Cytochalasin B metabolism, Female, Neutrophils metabolism, Parturient Paresis blood, Parturient Paresis immunology, Postpartum Period blood, Postpartum Period immunology, Pregnancy, Tetradecanoylphorbol Acetate metabolism, Calcium metabolism, Cattle Diseases immunology, Neutrophils immunology, Phagocytosis immunology
- Abstract
The aim of this study was to determine the effects of extracellular Ca(2+) concentration ([Ca(2+)](e)) on phagocytosis and intracellular Ca(2+) concentration ([Ca(2+)](i)) in bovine polymorphonuclear leukocytes (PMNs). The experiments were performed by using blood samples from parturient paretic and clinically normal parturient cows and manipulating the [Ca(2+)](e) in vitro. Phagocytosis by PMNs (with and without stimulation with phorbol myristate acetate and inhibition with cytochalasin B) and resting [Ca(2+)](i) were significantly lower in parturient paretic cows. Repletion of Ca(2+) in the extracellular media for the samples from these animals increased phagocytosis and resting [Ca(2+)](i). In the blood of clinically normal parturient cows, decreasing the [Ca(2+)](e) decreased phagocytosis and resting [Ca(2+)](i) in PMNs, but increasing the [Ca(2+)](e) did not affect phagocytosis. These results suggest that the hypocalcemic condition of parturient paretic cows in vivo causes decreased phagocytosis and resting [Ca(2+)](i) in PMNs, which may partly contribute to greater susceptibility to infection.
- Published
- 2003
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