Assessing nitrate metabolism in the intestinal tract by measuring breath nitric oxide and nitrous oxide, and its clinical significance

The application of statistical methods using VOCs to identify patients with lung cancer

In this work, an attempt was made to determine a group of lung cancer biomarkers. For this study, breath samples collected from 137 patients with confirmed lung cancer were analyzed by the SPME-GC/MS method. As a reference group, exhaled air from 143 healthy volunteers with different smoking habits (active smokers, passive smokers and nonsmokers) was applied. Statistical methods such as discriminant analysis (DA) and the CHAID model tree were used for data processing and evaluation. In the breath of patients with lung cancer, increased concentration of ethanol, acetone, butane, dimethyl sulfide, isoprene, propanal, 1-propanol, 2-pentanone, furan, o-xylene and ethylbenzene was observed in comparison to healthy nonsmokers. Furthermore, pentanal, hexanal and nonane were identified only in the breath of people who suffered from cancer. DA confirmed the importance of these compounds and allowed us to identify patients with lung cancer from healthy volunteers. In the exhaled air of healthy smokers (passive and active), a higher concentration of acetonitrile, benzene and furan derivatives was observed than in nonsmokers. DA revealed that in order to recognize healthy volunteers with different smoking habits by breath analysis, butyrolactone, carbon disulfide and dimethyl sulfide have to be considered.

Increased breath nitrous oxide after ingesting nitrate in patients with atrophic gastritis and partial gastrectomy

BACKGROUND

Toxic nitrite and N-nitroso compounds due to gastric bacterial growth are often detected in the stomach of patients with atrophic gastritis and partial gastrectomy. The aim of this study is to investigate whether breath N2O, a major metabolite of denitrification, detected after ingestion of nitrate is associated with atrophic gastritis and partial gastrectomy.

METHODS

Nine young, 16 normal older, nine atrophic gastritis and six partial gastrectomy subjects ingested 100 g lettuce, equal to 130 mg nitrate, and breath N2O was measured at 15-min intervals for 5 h. N2O was analyzed using an infrared-photoacoustic analyzer, and atrophic gastritis was diagnosed by pepsinogen test.

RESULTS

The mean breath N2O concentrations were higher in the following order at all times: partial gastrectomy>atrophic gastritis>normal>young. The maximum N2O concentrations in the patients with partial gastrectomy and atrophic gastritis were 1655 +/- 296 and 1350 +/- 200 (mean +/- S.E.) ppb, respectively, which were higher than that of the normal subjects, 827 +/- 91 ppb (P < 0.05). The maximum N2O concentration in young people was 527 +/- 86 ppb, which was lower than that of the normal older people (P < 0.051).

CONCLUSION

These higher N2O concentrations in gastric patients reflect bacterial growth in the stomach due to the reduction of gastric acid.