Rabbit Anti-GST monoclonal antibody, clone KN68-21

Chromium (Cr) represents an important source of metallic stress in plants. Working with maize (Zea mays) seedlings, we characterize the suppressive effects of exogenously applied NaHS (a hydrogen sulfide; [H2S] donor) on the toxic effects of Cr (VI). Heavy metal treatment reduced radicle and epicotyl lengths and fresh weights in seedlings at 6 and 9 days following germination. The negative Cr (200 mu M) effect was countered by application with NaHS (500 mu M) but this countering was reduced with the co-application of the H2S generation inhibitor hydroxylamine (HA) or the H2S scavenger hypotaurine (HT). The Cr-elicited H2O2 production was suppressed by NaHS and also by an inhibitor of the reactive oxygen species (ROS) generating NADPH oxidase (NOX). These effects were correlated with relative changes in carbomyl (-CO) and thiol (-SH) groups. Nitric oxide (NO) production increased by NaHS application with associated increase in S-nitrosoglutathione (GSNO) level, but low S-nitrosoglutathione reductase (GSNOR) activities indicating an elevated S-nitrosylation. Assessment of the role of the ascorbate-glutathione antioxidant cycle indicated that whilst ascorbate played at a best minor role, glutathione was more prominent. Methylglyoxal (MG) production was increased by Cr but reduced by NaHS through a mechanism which could be based on glutathione-S-transferase (GST) detoxification. Taken together data suggest that H2S acts to counter Cr effect in maize by NOX suppression, mostly likely by the well-characterised S-nitrosylation mechanism, as well as a reduction of MG accumulation.

The most challenging part of liver cancer detection is finding it in the very early stages. It has been argued that liver preneoplasia is found at the very earliest stages of liver cancer. The presence of a lesion is closely related to the development of HCC. We report herein a new class of iron-based T1MRI contrast agents which are nanoparticles of iron-tannic complexes (so-called Fe-TA NPs) that can be used for detecting liver preneoplasia. Preliminary assessment of their toxicity in healthy rats provides suitable imaging dose ranges with acceptable toxicity. In diethylnitrosamine (DEN) induced rats, it is shown that Fe-TA NPs are capable of enhancing MRI signals in rat livers having pre-neoplastic lesions within 60 minutes post-injection. The enhancement efficacy is strongly dependent on the characteristics of pre-neoplastic foci (GST-P+ foci). The highest enhancement was in good correlation with the size of GST-P+ foci and amount of Fe-TA NPs accumulated in the liver, and might be caused by the dysfunction of liver sinusoids along with cellular uptake capability of pre-neoplastic hepatocytes. Our results show that Fe-TA NPs are of great interest to develop as an efficient MRI imaging agent for risk assessment of liver cancer.