Exhaled ethane concentration in patients with cancer of the upper gastrointestinal tract - a proof of concept study.

There has been growing interest in the measurement of breath ethane as an optimal non-invasive marker of oxidative stress. High concentrations of various breath alkanes including ethane have been reported in a number of malignancies. Our aim was to investigate the use of novel laser spectroscopy for rapid reporting of exhaled ethane and to determine whether breath ethane concentration is related to a diagnosis of upper gastrointestinal malignancy. Two groups of patients were recruited. Group A (n = 20) had a histo-pathological diagnosis of either esophageal or gastric malignancy. Group B (n = 10) was made up of healthy controls. Breath samples were collected from these subjects and the ethane concentration in these samples was subsequently measured to an accuracy of 0.2 parts per billion, ppb. Group A patients had a corrected exhaled breath ethane concentration of 2.3 +/- 0.8 (mean +/- SEM) ppb. Group B patients registered a mean of 3.1 +/- 0.5 ppb. There was no statistically significant difference between the two groups (p = 0.39). In conclusion, concentrations of ethane in collected breath samples were not significantly elevated in upper gastrointestinal malignancy. The laser spectroscopy system provided a reliable and rapid turnaround for breath sample analysis.

Dynamic study of oxidative stress in renal dialysis patients based on breath ethane measured by optical spectroscopy.

The application of optical spectroscopy for rapid accurate measurement of breath biomarkers has opened up new possibilities for monitoring and diagnostics in recent years. Here, we report on how our recent advances in optical detection of ethane have enabled us to record dynamic breath ethane patterns for patients undergoing kidney dialysis. Ethane is well established as a breath biomarker for free radical induced cell degradation. Moreover, renal dialysis is known to induce such oxidative attack, and our measurements may offer insight into the nature of this assault. Specifically, we have discovered that patients undergo significant breath ethane elevation at the beginning of each dialysis session. We have found an inverse relationship between the magnitude of this effect and number of months patients have been receiving treatment. We comment on how further refinements of our technology will allow a more detailed evaluation of the ethane elevation effect and ultimately lead to the assessment of potential interventions.

Development of high-resolution real-time sub-ppb ethane spectroscopy and some pilot studies in life science.

We describe a high-resolution real-time spectroscopy system targeted to ethane gas with sensitivity > or = 70 ppt and response time from > or = 0.7 s. The measurement technique is based on a mid-IR lead-salt laser passing through a Herriott cell through which a gas sample flows. We compare wavelength scanning and locked configurations and discuss their relative merits. The technology has been motivated by clinical breath testing applications, ethane being widely regarded as the most important breath biomarker for cell damage via free-radical-mediated oxidative attack. We discuss preliminary human and animal studies in which ultrasensitive real-time ethane detection offers new diagnostic and monitoring potential.