Trace Elements in Human Body Fluids and Tissues

Abstract

Published figures for trace element concentrations in body fluids and tissues of apparently healthy subjects are widely divergent. For a considerable time, the apparent disparities were readily ascribed to biological sources of variation such as age, sex, dietary habits, physiological conditions, environmental exposure, geographical circumstances, or similar influences. Growing evidence, however, suggests that this interpretation may be seriously questioned in numerous instances. First, values obtained in reference materials leave no doubt that some previous studies must have been subject to gross analytical inaccuracies. Second, it has now been thoroughly documented that inadequate sample collection and manipulation may drastically distort the intrinsic trace element content of biological matrices. This review scrutinizes data reported by a number of investigators. In an effort to settle the currently flourishing confusion, critically selected reference values are set forth for trace element levels in human blood plasma or serum, packed blood cells, urine, lung, liver, kidney, and skeletal muscle tissue.

Streptococcus pneumoniae Surface Protein PcpA Elicits Protection against Lung Infection and Fatal Sepsis

“…These observations were consistent with the fact that the manganese concentration in the rat and human nasopharynx (Ͼ36 M) is high enough to suppress pcpA transcription (15,26,51,58). Under these conditions, pcpA tran- scription would be repressed by PsaR (25) in the nasopharynx.…”

Activation of Protein Phosphatase 1

“…sults") also do not support a role for Co 2ϩ . The fact that the amount of Mn 2ϩ in skeletal muscle ranges from 1 to 2 M (Versieck, 1985) and that 54 Mn 2ϩ did not show significant binding to PP1 catalytic subunit (Brautigan et al, 1980) (Versieck, 1985;Iyengar and Woittiez, 1988). Interestingly, metal analysis of a purified preparation of the rabbit liver PP1 revealed that although Zn 2ϩ and Fe 2ϩ were present in substoichiometric amounts, there was considerably more Zn 2ϩ and Fe 2ϩ detected than some other metal cations tested (Yan and Graves, 1982 -induced conformational change in the enzyme.…”

Opposite Effects of Mn2+and Zn2+on PsaR-Mediated Expression of the Virulence GenespcpA,prtA, andpsaBCAofStreptococcus pneumoniae

“…An important metal ion that S. pneumoniae could face is Zn 2ϩ , which is present in the human body in concentrations ranging from a few M to over 100 M (81). In the host, Zn 2ϩ is of great importance for immunity, as it is necessary for proper functioning of immune cells (28), and mild Zn 2ϩ deficiency severely affects immune function (72).…”