Magnesium ion (Mg 2+ ) and calcium ion (Ca 2+ ) control a diverse and important range of cellular processes, such as gene transcription, cell proliferation, neoplastic transformation, immune response and therapeutic treatment. Their characteristic biologic antagonism makes it important to treat the most important aspects of that competitive behavior together. This synopsis aims to be a useful means of promoting further research on the relationship between both cations and human health affected by environmental conditions.

The uptake of radiocalcium (⁴⁵Ca) and radiophosphorus (³²P) by 5 different types of experimental tumors have been studied. Through a chemical fractionation various fractions were obtained. Calcium is in corporated mainly in the acetic acid soluble fraction, while phosphorus in the HCl soluble fraction. The tumor necrosis shifts the calcium accumulation to the HCl soluble fraction. These findings indicated that the insoluble calcium is in a chemical form other than hydroxyapatite.

The effects of trypsin and EDTA on the cell coat of ascites tumor cells were studied by means of biochemical and electron microscopy techniques. EDTA seems to release, by chelation of the Ca²⁺-bridges, an outer layer of glycoproteins of presumably exogenous origin. On the contrary, trypsin produces a deeper enzymic cleavage which appears to affect the structural integrity of the bilayered cell membrane. The significance of the cell leakage in tumor cells and the effect of EDTA on the modification of this leakage by change of cell membrane permeability are discussed.

The Ca, Mg and P concentrations in experimental animal tumors as well as in human tumors were determined analytically. When these results were compared with ³²P and ⁴⁵Ca uptake values, it is inferred that Ca is incorporated slowly into the insoluble fraction, and that each type of tumor presents a characteristic pattern of chemical fractionation, which also is reflected in other tissues of the animal. The insoluble calcium has been found to be located in the cytoplasm.

The iron-binding capacity of different fractions of natural polyphenols extracts was determined by chromatographic and electrophoretic methods. Their effects on iron-induced calcium homeostasis changes in liver tissue suspension showed that mate tea and green tea extracts provoke a very significant inhibition of the iron effects, whereas it is much less significant with red wine extract. The biological importance of this phenomenon is discussed.

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Ruthenium red shows antitumor activity on experimental tumors. This growth inhibition seems to be related with the impairment of Ca-2+ transport both at the mitochondrial and at the cell membrane level. A sex influence modifying this inhibition and the systemic effects has been observed.

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