A method for measuring the rate of oxygen release from single microvessels.

Abstract

A system determining the rate of oxygen release from erythrocytes flowing in single microvessels was constructed with an inverted microscope by connecting 1) a scanning/grating spectrophotometer equipped with a photon-counting detector through a thin light guide, to obtain the visible absorption spectrum of a spot (5 microns in diameter) focused on a microvessel, 2) two photomultipliers (connected to a microcomputer via an analog-to-digital converter) through two light guides, to determine the flow velocity of erythrocytes by calculating the cross correlation between the light-intensity changes of two spots (3 microns in diameter, 5 microns apart from each other) focused on the microvessel, and 3) an image processor through a video camera, to estimate the diameter of microvessel from the digitized video images. The rate of oxygen release from single microvessels 7-25 microns in diameter in rat mesentery was measured under the superfusion of deoxygenated solution: 1) The maximal rate was obtained in capill...