Recent advances in biological monitoring of hexavalent chromium compounds

Metabolic pathways of carcinogenic chromium.

“…The obtained relaxation rate is determined by the squared dipole-dipole interaction energy that is modulated by molecular tumbling in solution. The mathematical expression is (43) [3] where µ o is vacuum permeability, ω H and ω e are the proton and electron Larmor frequencies, τ c is the motional correlation time, and r is the proton-metal distance. The isotropic hyperfine coupling of the unpaired electron with the metal nuclear spin modifies the Solomon equation (44); moreover, the Curie mechanism (42) is likely to contribute the nuclear relaxation pathway at the high magnetic field used.…”

“…Chromate, or dichromate, in fact, easily enters cells through the sulfate channel (3) and is quickly reduced by glutathione (GSH) (4), ascorbic acid (4), or cysteine (Cys) (4,5). In exposed animals, the ultimate step of the metabolic pathway yields Cr(III) inserted within the cell nucleus, where it cross-links DNA to proteins (mainly actin) or GSH (6,7).…”

“…In the early 1980s a new chromiumbinding oligopeptide, named "low-molecularweight chromium" (LMWCr) (15,(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31), also known as chromodulin (32), was isolated in tissues, mainly in the liver, of several mammals (24). Moreover, the use of Cr(pic) 3 as a dietary supplement has been challenged by its proven features of a) catalytically producing hydroxyl radicals and b) being potentially mutagenic as are all other Cr(III) compounds (33).…”

“…Since the so-called glucose tolerance factor failed to be chemically characterized (16), chromium tris-picolinate [Cr(pic) 3 ] has been proposed as the biologically active form of Cr(III) and extensively commercialized (17)(18)(19). In the early 1980s a new chromiumbinding oligopeptide, named "low-molecularweight chromium" (LMWCr) (15,(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31), also known as chromodulin (32), was isolated in tissues, mainly in the liver, of several mammals (24).…”

Effect of hexavalent carcinogenic chromium on carp Cyprinus carpio immune cells

“…In cell culture experiments, hexavalent chromium suppressed lymphocyte proliferation and immunoglobulin production (Borella et al 1990). According to the uptake-reduction model of chromium, Cr(VI) as the chromate anion under physiological conditions readily crosses the cell membrane through the sulphate channel (Wiegand et al 1988), while Cr(III) enters the cell via diffusion and phagocytosis at . This results in a much lower toxicity of trivalent chromium compared to the hexavalent state.…”