Preliminary data are reported on time-resolved measurements of photosensitized phosphorescence of singlet molecular oxygen (2 = 1270 nm) excited by pulses of a copper-vapor laser in aqueous buffer solutions (pH 7.4) containing water-soluble porphyrins and bovine blood plasma. Reliable phosphorescence kinetic curves were detected after 100-500 s signal accumulation that corresponded to (1--6) x 106 laser shots. With no plasma and no oxygen purging the phosphorescence kinetics comprised the rise and decay phases with a maximum at 2.5 _ts after a laser shot. Addition of 1% bovine blood plasma (vol/vol) caused ten-fold decrease of the phosphorescence intensity. With higher plasma concentration the phosphorescence was not detected. When oxygen bubbled through the plasma-containing solutions during laser irradiation and the solution flowed at a rate of 1 .5 ml/s through the spectrophotometric cell, the phosphorescence intensity increased and was observed at plasma concentration up to 20%. The phosphorescence intensity of a 20% plasma solution was about eight fold less than that of a porphyrin solution containing no plasma. With 20% plasma the phosphorescence rise-time was in a range of 1--i .5 is, the phosphorescence decay-time was 7--8 ts. Further experiments are in progress in order to optimize our experimental set-up for measurements in whole blood serum and plasma.
Transmittance spectra and spectra of optical loses due to absorption and scattering of different biofluids were registered by spectrophotometer DU-64 Beckman in the range of wavelength from 200 to 900 nm. The alteration of spectra of blood serum and whole blood were observed after irradiation of the samples by laser light (633 or 850 urn). The preliminary results indicating that the laser effects depend on the initial biophysical and biochemical state ofblood are discussed.
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