Carbon isotope fractionation between blood and expired CO2 at rest and exercise.

Carbon isotope fractionation occurs between bicarbonates and gaseous CO2. Accordingly, expired CO2 could be impoverished in 13C vs. blood CO2 (approximately 90% bicarbonates).

[Daily changes in the carbon isotope composition of CO2 in expired air of persons with various metabolic disorders].

Daily variations of the aspiration CO2 carbon isotope content (CIC) were studied at three metabolic states: norm, insulin-dependent diabetes (IDD), and obesity. The groups of subjects were studied in a clinic during 24 hours. Analysis of the delta 13C daily curves of the exhaled air CO2 allowed us to find the link between variations of CIC with daily rhythms in the organism and with metabolic shifts at IDD and obesity.

[Variability of some isotopic characteristics of carbon in man].

Variability of some carbon isotope characteristics in man (i.e. carbon isotope composition of hair, blood, nails, expiratory carbon dioxide) was studied.