Serum protein oxidative damage

The aim of the present study was to evaluate the effect of LLLT on oxidative markers in serum and tissue biopsies of healing ulcers before and after the 8th session of an LLLT course of chronic leg ulcer treatment. Oxidative damage was assessed in terms of lipid peroxidation reflected by serum malondialdehyde (MDA) level, protein oxidation was measured in terms of tissue protein carbonyls (PCb), and DNA damage was measured in terms of DNA fragmentation. Antioxidative activity was estimated by measuring activity of SOD, GPX and CAT enzymes. 

In vitro, an aqueous extract of coptis was found to displace bilirubin from serum protein binding as assessed by the peroxidase oxidation method. The authors indicated that coptis may increase the risk of brain damage by free bilirubin in jaundiced infants (Yeung et al. 1990). 

Exposure of rats to sodium dichromate at 0.4 mg chromium(VI)/m3 for 90 days did not cause abnormalities, as indicated by histopathological examination of the kidneys. Serum levels of creatinine and urea and urine levels of protein were also normal (Glaser et al. 1985, 1990). Furthermore, no renal effects were observed in rats exposed to 0.1 mg chromium/m3 as sodium dichromate (chromium(VI)) or as a 3 2 mixture of chromium(VI) trioxide and chromium(III) oxide for 18 months, based on histological examination of the kidneys, urinalysis, and blood chemistry (Glaser et al. 1986, 1988). Rats exposed to 15.5 mg chromium(IV)/m3 as chromium dioxide for 2 years showed no histological evidence of kidney damage or impairment of kidney function, as measured by routine urinalysis. Serum levels of blood urea nitrogen, creatinine, and bilirubin were also normal (Lee et al. 1989). 

Peroxynitrite is a nonspecific oxidant that reacts with all classes of biomolecules depleting low-molecular-weight antioxidants, initiating lipid peroxidation, damaging nucleic acids and proteins. Its reactions are much slower than those of the hydroxyl radical but are faster than those of hydrogen peroxide. Comparison of peroxynitrite reactivity with various amino acid residues of human serum albumin have shown that cysteine, methionine, and tryptophan are the most reactive... 

An interesting system for the delivery of proteins into the cytosol was recently reported. The system was based on a branched polyethylenimine (PEI) which was modified by introducing thiol functions and subsequently polymerized (oxidized) with the formation of disulfide bonds. This polymer was able to complex bovine serum albumin (BSA), an anionic protein. The PEC formed showed negligible cytotoxicity and the complexation did not result in structural damage of the protein. The complexes could be internalized into the endosomes and lysosomes and could escape from them. 

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