Leukocyte phagocytosis

Vinca alkaloids (vincristine, vinblastine, vindesine) are derived from the periwinkle plant (Vinca rosea), they bind to tubulin and inhibit its polymerization into microtubules and spindle formation, thus producing metaphase arrest. They are cell cycle specific and interfere also with other cellular activities that involve microtubules, such as leukocyte phagocytosis, chemotaxis, and axonal transport in neurons. Vincristine is mainly neurotoxic and mildly hematotoxic, vinblastine is myelosuppressive with veiy low neurotoxicity whereas vindesine has both, moderate myelotoxicity and neurotoxicity. 

Vinca alkaloids are derived from the Madagascar periwinkle plant, Catharanthus roseus. The main alkaloids are vincristine, vinblastine and vindesine. Vinca alkaloids are cell-cycle-specific agents and block cells in mitosis. This cellular activity is due to their ability to bind specifically to tubulin and to block the ability of the protein to polymerize into microtubules. This prevents spindle formation in mitosing cells and causes arrest at metaphase. Vinca alkaloids also inhibit other cellular activities that involve microtubules, such as leukocyte phagocytosis and chemotaxis as well as axonal transport in neurons. Side effects of the vinca alkaloids such as their neurotoxicity may be due to disruption of these functions. 

Deposition of urate crystals in synovial fluid results in an inflammatory process involving chemical mediators that cause vasodilation, increased vascular permeability, complement activation, and chemotactic activity for polymorphonuclear leukocytes. Phagocytosis of urate crystals by leukocytes results in rapid lysis of cells and a discharge of proteolytic enzymes into the cytoplasm. The ensuing inflammatory reaction is associated with intense joint pain, erythema, warmth, and swelling. 

Levin, M. et al., PCBs and TCDD, alone and in mixtures, modulate marine mammal but notB6C3Fl mouse leukocyte phagocytosis J. Toxicol. Environ. Health, A, Current Issues, 68, 635, 2005. 

Bjerknes, R. and Bassoe, C.-F. (1983) Human leukocyte phagocytosis of zymosan particles measured by flow cytometry. Acta Pathol. Microbiol. Immunol. Scand. Sect. C. 91, 341-348. 

Experiments performed in rabbits and guinea pigs showed marked stimulation of leukocyte phagocytosis following application of various dilutions of... 

Oxidative deiodination of T4 in a process that includes ether link cleavage produces DIT, I-, and iodinated protein. Since this mechanism accounts for 40-50% of all T4 degradation during human leukocyte phagocytosis, the suggestion has been made that this process may contribute to the bactericidal capacity of the leukocyte50. 

K8. Kvarstein, B., and Halvorsen, K. S., Oxygen consumption during the initial stage of human leukocyte phagocytosis as a test for chronic granulomatous disease. Scand. ]. Clin. Lab. Invest. 26, 175-178 (1970). 

The inhibition of cyclooxygenase by NSAID occurs at concentrations (0.01-10 pg/ml) comparable to their therapeutic levels. On the contrary, much higher concentrations of these drugs are required to regulate other processes which might underly their anti-inflammatory effect, such as uncoupling of oxidative phosphorylation or inhibition of leukocyte phagocytosis. A remarkable parallelism has been... 

The therapeutic approach differs depending upon whether the patient is in the acute or chronic phase. In acute gout, the drug of choice has for a long time been colchicine. The exact mode of action of colchicine is not known, but it is believed to inhibit leukocyte phagocytosis and thereby interfere with the inflammatory cycle. Phenylbutazone and indomethacin are also used in the treatment of the acute phase of gout. The administration of anti-inflammatory corticosteroids enhances the effect of colchicine. 

Wagner H, Jurcic K (1996) A new flowcytometric assay for measuring the leukocyte phagocytosis activity of immunostimulating plant extracts, polysaccharides and various low molecular weight compounds. Phytomedicine 3 (Suppl 1) 31... 

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