The speaker also cautioned and provided data to suggest that isoprostane analysis may not provide accurate indication of the severity of oxidant insult at high oxygen pressures. Dr. Terence Risby of Johns Hopkins University was the third speaker of this session and spoke on the use of breath biomarkers to measure oxidant stress. Breath ethane is the most commonly used gas and is used as a marker of lipid oxidation. Gas chromatography is the instrumentation used for measurement. The use of breath ethane is potentially interfered by smoking.
Smokers have twice the breath ethane as non-smokers.
The speaker also discussed typical coefficients of variation associated with breath ethane measurements. These methods were reviewed and several applications and limitations of each were discussed. Dr Rodriguez began his talk by noting that although many diseases are associated with oxidative stress, the necessity of knowing the location of the damage is becoming increasingly more important in order to assess and understand the individual risks associated with oxidative stress. Indeed, Dr Rodriguez pointed out that traditional methods that evaluate DNA damage in terms of the form and frequency of DNA base modification are increasingly being augmented by methods that identify base damage hotspots, the distribution of base modifications along the DNA sequence, and the correlation between DNA modifications and known mutational hotspots. Appropriately conducted, this technique allows researchers to precisely map where the DNA damage occurs, identify sequence hot-spots, and establish the linkage between DNA damage and known mutations.