title: High-sensitivity device for continuous measurements of tissue O2 uptake.
abstract: An analysis system for continuous measurements of O2 uptake by rat diaphragm during several hours is described. The tissue was set in a chamber where a medium was flowing at a known and constant flow rate, temperature, and partial pressure of oxygen (PO2). The decrease in PO2 of the medium was measured with a Clark O2 cathode at the outlet of the chamber. To increase the sensitivity of the system and the signal-to-noise ratio of the measurements, a sweeping device was designed. It provided homogenization of the medium in the chamber. The main characteristics of this analysis system are a) a sensitivity of +/-0.2% of the mean PO2 value of the perfused medium, +/-0.8% of the mean O2 uptake of rat diaphragm, b) a linearity of +/-1.75% in the range of 0+/-200 Torr, c) a stability of +/-0.38% of the initial PO2 value, and d) a time constant of 8 min 30 s. This type of system can be used for high-sensitivity measurements of O2 uptake of any tissue after adaptation of the chamber and of the medium flow rate.
mesh_terms: D000818:Animals; D003964:Diaphragm / Q000378:metabolism; D004780:Environment, Controlled; D005260:Female; D010101:Oxygen Consumption; D011048:Polarography / Q000379:methods*; D051381:Rats