Effects of extracellular Ca2+ on phagocytosis and intracellular Ca2+ concentrations in polymorphonuclear leukocytes of postpartum dairy cows.

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.

Expression of mRNA of chemokine receptor CXCR4 in feline mammary adenocarcinoma.

The expression of mRNA of the chemokine receptor CXCR4 in 65 surgically resected mammary adenocarcinomas from cats was investigated by in situ hybridisation. No expression of the receptor's mRNA was detectable in the mammary tissue of healthy cats, but it was expressed in areas adjacent to necrosis, surrounding blood vessels and cells infiltrating the lymphatics of 47 (72.3 per cent) of the 65 samples. There was a significant relationship between lymphatic infiltration by neoplastic cells and the expression of the receptor's mRNA (P < 0.005), but there was no significant relationship between its expression and the one-year survival of the cats.