[Short-period oscillations of isotopic carbon in CO2 from expired air in different human functional states]. / Korotkoperiodicheskie kolebaniia izotopnogo sostava ugleroda CO2 vydykhaemogo vozdukha v razlichnykh funktsional'nykh sostoianiiakh cheloveka.

The examination of diurnal variations in carbon isotope composition of CO2 under different hormonal-metabolic states in man revealed short-period inphase oscillations with a period of about 2-3 h. The oscillations occur throughout 24 h and their period is little dependent on the functional state of the organism. In endocrine pathologies, substantial differences in oscillation amplitude are observed. The relationship between the variations in carbon isotope composition of CO2 of expired air and energy exchange in cells of insulin-dependent tissues of the organism is substantiated.

[Average daily values of the isotopic carbon composition in expired air and urea in human urine in normal states and in some endocrine disorders]. / Srednesutochnye znacheniia izotopnogo sostava ugleroda CO2 vydykhaemogo vozdukha i mocheviny mochi u cheloveka v norme i pri nekotorykh éndokrinnykh patologiiakh.

Daily average carbon isotope composition of CO2 of expired air and urine urea in patients being in different hormonal-metabolic states was determined. The observations were carried out under conditions of clinic to provide standard diet, and the same daily and food taking regimes. In all persons, a substantial increase enrichment in 12C of CO2 of expired air (by 3-6%) and 13C of urine urea (by 3-5%) relative to carbon of food was revealed. Marked variations in these characteristics in norm, on starvation and in endocrine pathologies were found. A relationship between the carbon isotope composition and the metabolic shifts characterizing the deviations of the studied functional states from norm was established. The changes in the isotope characteristics and their relation to the hormonal-metabolic status of the organism are interpreted in terms of the model for cell fractionation of carbon isotopes proposed earlier.

[Daily changes in the carbon isotope composition of CO2 in expired air of persons with various metabolic disorders]. / Sutochnye izmeneniia izotopnogo sostava ugleroda CO2 vydykhaemogo vozdukha u cheloveka pri nekotorykh narusheniiakh metabolizma.

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. At metabolic norm it is possible two phases on the daily curve, corresponding to daytime and nighttime metabolism types with hormonally regulated transition between them. The daytime phase of the curve consists of altering maxima and minima, linked to periodicity in feeding and movement activity. The nighttime phase is characterized by continuous enrichment of CO2 by 12C. At IDD in insulin therapy conditions the most prominent difference from norm and obesity is the stable CIC at nighttime. At daytime during weakening of the exogenous insulin action there appear horizontal regions on the delta 13C CO2 curves, similar to the nighttime behaviour. At obesity the daily curves are close to the normal ones, but they are more smooth and impoverished in 13C. No clear transition between the daytime and nighttime metabolism types can be observed. At obesity and IDD the character of the daily curves can be observed.