No abstract

Trace elements are involved in many key pathways involving cell cycle control. The influence of zinc and zinc chelator (TPEN) on transcription levels of the main zinc transporters (ZnT1 and ZIP1) in the HT-29 colorectal cell line has not been reported. Proliferation of HT-29 cells was measured using the methylene blue assay after exposure to zinc (two concentrations), TPEN (two concentrations), or a combination of zinc and TPEN (simultaneously and sequentially) for 4 h, 8 h, and 24 h. The transcription levels of ZnT1, ZIP1, vascular endothelial growth factor (VEGF), and caspase-3 were determined using reverse transcriptase real-time polymerase chain reaction (RT-PCR) after exposure of cells to zinc and TPEN. The zinc content in the substrate (medium used for culture) was determined using atomic absorption spectrometry. TPEN decreased cellular proliferation causing complete cell death by 8 h. Zinc had a protective effect against short periods of exposure to TPEN. There was no correlation between the transcripts of main zinc transporters and the zinc content in the substrate. The zinc content in the substrate remained constant after varying periods of cell culture. TPEN decreased the transcript levels of caspase-3 and VEGF, which are surrogate markers for apoptosis and angiogenesis. Zinc chelation of HT-29 cells causes cell death. Zinc appears to be protective for short periods of exposure to TPEN but has no protective effect on prolonged exposure. HT-29 cells are not able to counteract the effect of intracellular chelation of zinc by altering zinc transport. Further research into the mechanisms of these findings is necessary and may lead to novel therapeutic options.

No abstract

A semi-automated, metabolite prior-knowledge-based, lineshape fitting analysis has been developed to assess the dynamic biochemical changes found in ex vivo 31 P NMR pig liver preservation studies. Due to the inherent experimental limitations of the ex vivo study and the complexity of the composite phosphorus resonances, metabolite information obtained in vitro was incorporated into the ex vivo analysis. This approach has allowed complete metabolite analysis (phosphomonoesters, inorganic phosphate, phosphodiesters and nucleotide triphosphates) in over 2000 spectra in a fraction of the time compared with more conventional analysis methods. The developed analysis will enable complete and rapid assessment of the biochemical changes in ongoing cold preservation studies of the pig liver which will result in thousands of ex vivo 31 P NMR spectra. It is also envisaged that comparative studies on human donor livers will be carried out, in which this type of analysis would be the method of choice. Moreover, this kind of analysis approach could be advantageous in many complex in vivo NMR spectroscopy applications. Copyright