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The determination of the cellular volume of avian, porcine and bovine phagocytes and bovine mammary epithelial cells and its relationship to uptake of tilmicosin
Author(s) -
Bernard Scorneaux,
Thomas R. Shryock
Publication year - 1999
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1046/j.1365-2885.1999.00185.x
Subject(s) - tilmicosin , epithelium , chemistry , biology , microbiology and biotechnology , biochemistry , genetics , antibiotics
In order to compare the intracellular concentration of antimicrobial agents in phagocytic and nonphagocytic cells, the knowledge of their cell volume is essential. For the first time, the determination of the avian, porcine, and bovine polymorphonuclear neutrophils (PMN), monocyte‐derived macrophages, macrophages, and bovine mammary epithelial cell volume was performed using [ 3 H]‐water and [ 14 C]‐carboxyinulin. The comparison of all the cells showed that the PMN have a size range between 3.58 and 4.04 μL per mg of protein, and are smaller than the monocyte‐derived macrophages and mammary epithelial cells (4.32–5.01 μL per mg of protein). The macrophages show the largest size (5.84–6.57 μL per mg of protein). The cellular uptake of tilmicosin in these cells was then determined. The examination of the intracellular/extracellular concentration ratios (C i/ C e ) after 4 h of incubation with 10 mg/mL of [ 14 C]‐labelled tilmicosin revealed that tilmicosin was well accumulated and showed a ratio of 137, 169 and 193 in avian PMN, porcine PMN, and bovine alveolar macrophages, respectively. The cellular uptake data also demonstrated that tilmicosin accumulated in nonphagocytic bovine mammary epithelial cells. The importance of the use of the appropriate species and cell type specific cell volume values for calculations was exemplified by calculating the C i/ C e of tilmicosin using cell volume data found in the literature for human and mouse cells. The subsequent comparison of these data with the C i/ C e calculated with the actual cell volume appropriate for the species tested revealed an under evaluation of 3–13% in monocyte‐macrophages, an over evaluation of 7–18%, 16–31% and 69% in PMN, macrophages, and epithelial cells, respectively. This study highlights the importance of the proper cell volume in order to determine the C i/ C e . Moreover, the cell volumes determined here for avian, porcine and bovine cells should facilitate further in vitro and in vivo cellular studies by veterinary researchers.