Identification of isoprenoid‐type components in human expired air: A possible shunt pathway in sterol metabolism

Abstract

Expired air samples have been analyzed from three groups of human subjects (normal, liver dysfunction, lung cancer) and the baboon (Papio anubus). Of the several hundred compounds present, three compounds were of particular interest due to their structural relationship to the isoprenoid-type intermediates in the sterol pathway. These compounds were 1-methyl-4-(1-methyl-ethenyl)-cyclohexene, 6-methyl-5-hepten-2-one, and 6,10-dimethyl-5,9-undecadien-2-one. Hydroxyacetone was also found in all samples screened. The relationship of these compounds to the non-sterol pathway of mevalonate metabolism is discussed.

Investigation of volatile biomarkers in lung cancer blood using solid-phase microextraction and capillary gas chromatography?mass spectrometry

“…5 that the concentrations of volatile compounds except hexanal and heptanal in cancer blood were very close to those in normal blood. Phillips et al [7,8] and O'Neill and co-workers [5,6] analyzed volatile compounds in breath from lung cancer patients, 22 and 28 volatile compounds in exhaled breath were regarded as biomarkers, respectively [5][6][7][8]. Compared to volatile composition of lung cancer breath, all of 23 compounds in blood were found in exhaled breath.…”

“…Gas chromatography-mass spectrometry (GC-MS) combined with some sample collection and concentration techniques such as cold trapping and adsorptive binding was developed for analysis of breath gas [6][7][8][9][10][11][12][13]. Phillips et al [14,15] developed a portable breath-collecting apparatus and applied to determination of volatile markers.…”

“…In 1971, Pauling et al [4] analyzed the normal human breath by gas chromatography (GC), who found a several hundred volatile organic compounds (VOCs) in exhale gas. During 1985During -1988, O'Neill and co-workers [5,6] studied the exhaled air from patients with lung cancer and 28 breath biomarkers including alkanes and benzene derivatives were found in lung cancer. Recently, Phillips et al [7,8] correlated the presence of 22 VOCs including two aldehydes of hexanal and heptanal as markers of lung cancer.…”

Analytical challenges in breath analysis and its application to exposure monitoring

“…These bags must be made of inert materials to avoid both diffusion and reactions between the compounds and the bag. The most commonly used material is Tedlar [10,20,[25][26][27]29,44,61,[70][71][72][73][74] but other materials such as Teflon [9,53,74,75], FlexFoil [74], and Nalophan [74] are also used.…”

“…Pre-concentration on solid sorbents followed by thermal desorption (TD) is the most frequent method for the analysis of VOCs in breath samples [9][10][11][12][13]16,[19][20][21][22][23][24][25][26][27][28][43][44][45]47,55,62,75,[81][82][83][84][85]95,96]. Sorbent traps present the advantages that they can be prepared on a micro-scale and coupled on-line with a GC system to allow near real-time measurements [97][98][99][100][101], and the sorbent configuration can be easily changed to adapt to different compounds.…”