title: Analyses of the temperature and pH effects on the complexation of magnesium and calcium in human blood plasma: an approach using artificial neural networks.
abstract: The temperature and pH effects on the equilibrium of a blood plasma model have been studied on the basis of artificial neural networks. The proposed blood plasma was modeled considering two important metals, calcium and magnesium, and six ligands, namely, alanate, carbonate, citrate, glycinate, histidinate and succinate. A large data set has been used to simulate different concentrations of magnesium and calcium as a function of temperature and pH and these data were used for training the neural network. The proposed model allowed different types of analyses, such as the effects of pH on calcium and magnesium concentrations, the competition between calcium and magnesium for ligands and the effects of temperature on calcium and magnesium concentrations. The model developed was also used to predict how the variation of calcium concentration can affect magnesium concentrations. A comparison of neural network predictions against experimental data produced errors of about 3%. Moreover, in agreement with experimental measurements (Wang et al. in Arch. Pathol. 126:947-950, 2002; Heining et al. in Scand. J. Clin. Lab. Invest. 43:709-714, 1983), the artificial neural network predicted that calcium and magnesium concentrations decrease when pH increases. Similarly, the magnesium concentrations are less sensitive than calcium concentrations to pH changes. It is also found that both calcium and magnesium concentrations decrease when the temperature increases. Finally, the theoretical model also predicted that an increase of calcium concentrations will lead to an increase of magnesium concentration almost at the same rate. These results suggest that artificial neural networks can be efficiently applied as a complementary tool for studying metal ion complexation, with especial attention to the blood plasma analysis.
authors.affiliation: Departamento de Química - ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: J C D
authors.initials: JC
authors.lastname: Conway
authors.forename: A
authors.initials: A
authors.lastname: Liparini
authors.forename: J R
authors.initials: JR
authors.lastname: de Oliveira
authors.forename: J C
authors.initials: JC
authors.lastname: Belchior
mesh_terms: D002118:Calcium / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008274:Magnesium / Q000097:blood*; D016571:Neural Networks, Computer; D009942:Organometallic Compounds / Q000097:blood; D013696:Temperature
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D008274:Magnesium; D002118:Calcium