Abstrakt

Background: Currently developed microenzyme detectors allow a noninvasive meas- urement of inflammatory markers and L-lactate in exhaled breath condensate (EBC). In a group of young and healthy subjects, we proved if L-lactate can be detected in EBC at rest and during mild-to-moderate exercise. Methods: During resting conditions as well as at 60 and 120 Watt external load on a cycle ergospirometer 100 l exhaled air were collected under stationary load conditions on 21 healthy subjects. Exhaled breath condensate (EBC) was obtained by cooling the expired air volume. The analysis was performed within 90 min using an ECo Check amperometer (Viasys Health Care). Lactate measurements were performed using a bi-enzyme sensor after lactate oxidase-induced oxidation of L-lactate to pyruvate and H₂O₂. In a second enzyme reaction H₂O₂ was measured amperometrically by means of a biosensor after chemical reaction catalysed by peroxidase. The rates of release of L-lactate in nmol/min were calculated from the concentrations of L-lactate and the time of collection. Results: At rest 100 l exhaled air were collected in 9.4 ± 4.35 min, and 1.25 ± 0.48 ml EBC were obtained, at the 60 Watt step 1.21 ± 0.40 ml EBC were collected in 6.15 ± 1.8 min, and at 120 Watt in 4.35 ± 0.9 min 1.06 ± 0.29 ml EBC. At rest, there was a mean rate of L-lactate of 3.1 ± 2.67 nmol/min, which increased on the 60 Watt step to 9.3 ± 4.9 nmol/min (p < 0.0005), and at 120 Watt to 15.9 ± 10.6 nmol/min (p < 0.0005). The rate of L-lactate was proportional to the rate of oxygen uptake (r = 0.99). Conclusions: Significantly measurable concentrations of L-lactate in the exhaled breath condensate were found already under resting conditions. During external load, an increase in the L-lactate concentration was found, closely correlating with oxygen consumption. A probable correlation between L-lactate concentration in EBC and arterialized blood is going to be studied in pursuing investigations.

Autoreninformation

Autoren

• E. Marek¹
• K. Mückenhoff²
• H.J. Streckert³
• G. Becher⁴
• W. Marek¹

Abteilungen

• ¹ Institut für Arbeitsphysiologie an der Augusta-Kranken-Anstalt Bochum,
• ² Institut für Physiologie, Ruhr-Universität Bochum,
• ³ dsdiagnostics GmbH Witten,
• ⁴ FILT GmbH Berlin

Adresse

PD Dr. rer. nat. W. Marek
Institut für Arbeitsphysiologie
an der Augusta-Kranken-Anstalt
Bergstraße 26
D-44791 Bochum
Email: [email protected]

Citation