Eine neue Methode zur Untersuchung der Capillarpermeabilität

Scanning microfluorometry in intravital microvascular research

Our own development of fluorometric scanning techniques in intravital microscopy of the microcirculation is described. Very tiny amount of fluorometric substances are detected with a high temporal and locational resolution. The everted small intestinal mesentery of the rat serves as a model. We have given a detailed description of the microscopes used, the optical systems, the conditions of measurement of the microfluorometry, the scanning techniques and the evaluation of the measurement data. The present state of technical development detects 10(-12) g of a fluorochromed plasma protein in 8 ms in a measurement field of 2 microns 2. The four-digit measurement data of a scanning line of 200 microns length in 0.25 micron locational resolution are registered in about 2 s.

Microphotometric techniques in intravital microcirculatory studies

Intravital microscopic techniques were developed in order to measure plasma proteins: (1) circulating in the streaming blood of microcirculatory vessels of the exposed rat mesentery, (2) permeating the vessel wall, and (3) moving through the perivascular interstitial tissue. By means of the ultramicrospectrophotometry, the absorbance of proteins containing aromatic amino acids at 280 nm is measured. Absolute amounts of proteins in the range of picograms are measured in a circular measuring field with a diameter of 17 micrometers. Problems of calibration and of unspecific light scattering are discussed. The scanning microfluorometry makes use of the fluorescent labelling of the plasma proteins. Interstitial tissue with a capillary vessel containing labelled proteins is measured at high speed. A motor-driven object stage synchronized with a measuring system uses scanning lines to traverse the tissue. The data are then processed by a computer. In this way we get continuous quantitative information about the dynamics of protein permeability, starting from time zero. The measuring of the fluorescence intensity and the speed of the fluorometric system are further improved by a computerized 10 kHz scanning device.