Abstract
Inductively coupled plasma mass spectrometry (ICP-MS), a comparatively new multi-element analytical technique was employed for elemental determination in human hair, placenta and brain samples. The performance criteria of ICP-MS such as precision, accuracy and detection limits were assessed. For most elements sub ng ml-1 limits of detection were achieved. Amino acid analysis of human foetal brain extracts was performed using reverse phase high performance liquid chromatography. Prior to separation, samples were derivatised using o-phthaldialdehyde derivatising reagent. Precision and limits of detection were assessed. For most amino acids detection limits of sub nmoles ml-1 were achieved. Hair is commonly used as a diagnostic and monitoring tool to observe the effects of mineral supplementation on an individuals bodily status, especially prior and after pregnancy. Some of the factors influencing the elemental content of hair were investigated. Analysing scalp hair of thirteen female individuals showed that longitudinal variations exist in elemental composition of human scalp hair. Radial and longitudinal diffusion of Co, Zn and Cd were investigated in scalp hair, using tresses of "virgin" hair. Both radial and longitudinal diffusions occurred for all three elements. Analysis of scalp hair of thirty-seven females and twenty male subjects from United Kingdom showed that there were significant differences in concentrations of Mg, K, Ca, Mn and Fe between males and females. Effects of six months mineral supplementation (18.6 mg Mg, 31.0 mg Ca, 1.2 mg Cr, 4.0 mg Mn and 7.5 mg Zn daily) on elemental content of hair was investigated in six female subjects and no significant changes were observed in the levels of supplemented elements (Mg, Ca, Cr, Mn and Zn). For elemental analysis of placenta, the importance of defining the location of the sampling site was demonstrated by investigating levels of Mg, Ca, Mn, Fe, Cu, Zn and Pb in different regions of a placental disc. Significant variations were found in the elemental content of the various regions. The peripheral region of the placental discs from fifty black females from Soweto, South Africa, were analysed for their elemental content in relation to birthweight and gestational age of their neonates. Concentrations of Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Mo, Cd and Pb were determined. Positive correlation was found for Mg, K, Fe, Cu and As with both medical parameters and Zn with gestational age. Lower concentrations of Mg (P < 0.10), Cu (P < 0.05), Zn (P < 0.10) and As (P < 0.001) were found in low birthweight cases compared to high birthweight groups. Comparison with an English population showed that significant differences existed in the placental elemental levels of the two communities. The contributing factors are fully discussed. Analysis of Mg, P, Ca, Fe, Cu, Zn, Rb, Sr, Mo and Pb in foetal brain tissues of eleven stillbirths and ten socially terminated neonates showed that stillbirth brains contained significantly (P < 0.001) higher levels of Pb compared to the controls. Analysis of four different regions of the brains; hippocampus, cerebrum, cerebellum and basal ganglia, also showed higher concentrations of Pb in all the four regions in comparison with the controls. Most elements showed significant differences in their regional concentrations within each study group and the patterns were different in stillbirths compared to the social terminations. However, concentration of Zn was predominantly higher in hippocampus compared to the other regions, in both study groups. The concentrations of fifteen amino acids were measured in the same foetal brain samples used for elemental analysis. Stillbirth brain tissues had lower levels of alanine (P < 0.05), phenylalanine (P < 0.05) and Isoleucine (P < 0.05) compared to social terminations. Regional brain analysis of amino acids revealed higher concentrations of glutamic acid, aspartic acid and serine in the hippocampal region. The significance of these results and any relationship found between the amino acid and elemental content of the analysed foetal brain samples are discussed in detail. Overall this work demonstrates and supports the importance of an adequate balance of elements and amino acids for a successful outcome of pregnancy.