Occupational Health - Public Health Poster Session
Discussion and Conclusion
Lipolysis-induced hemolysis (LIH) was found to be temperature-dependent, minimal at 0°C and several-fold increased at 37°C. It was also greatly enhanced by increasing concentrations of magnesium cations and inhibited by moderate to excess amounts of calcium cations. The inhibitory effect of calcium may be related to its ability to form soaps with the released ionized forms of free fatty acids and thereby prevent them from causing non-specific cytolysis. This would suggest that only the ionized fatty acids are able to cause cytolysis. The level of ionized FFA in the freshly collected milk has been estimated to be less than 1mg/dL and only slowly rises in contrast to a more rapid rise in the levels of total FFA, most of which form soaps with the breast-milk calcium and other ions (Lavine & Clark, 1987). Excess calcium cations might also provide a support for the cells against toxic damage (Smith & Sandy, 1985). The absence of extra-cellular calcium cations has also been recognized as a source of oxidative stress in cells, which is capable of enhancing the cells` susceptibility to external toxins (Thomas & Reed, 1988).
The toxicity of FFA was enhanced by the presence of extracellular magnesium cations. This might act by increasing the intracellular levels of this cation, which is known to independently enhanced the toxicity of certain other toxic agents (Patel et al, 1994). Magnesium is a known activator of about 300 enzymes which govern energy utilization, cell permeability, and ionic membrane currents in the cardiac conducting and other biological cells (Keren &Tzivoni, 1990). The effects of temperature on the rate cytolysis by stored milk, suggest mechanisms involving receptor-based uptake and other internalisation mechanisms across the plasma membrane, which are energy-requiring.
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|Ogundele, M.O.; (1998). CHARACTERIZATION OF LIPOLYSIS-INDUCED TOXICITY BY STORED HUMAN BREAST-MILK. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/occupational/ogundele0297/index.html|
|© 1998 Author(s) Hold Copyright|