Albumin macroaggregates and measurements of regional blood flow: validity and application of particle sizing by Coulter counter.

A method is described for rapid determination of the distribution of particle sizes of albumin macroaggregates by using an electronic counter (Coulter counter). The applicability of this method of analysis to batch quality control has been demonstrated by examining batches before and after changes were made in the mode of synthesis. Seven injections of macroaggregates were made, in 3 experiments, into the arterial inflow of the isolated rabbit heart (perfused with Ringer’s solution), and the coronary venous effluent was analyzed for the distribution of particle sizes; 98.1 per cent of the emerging particles had volumes less than 120 µ, and 97 per cent had maximal diameters less than 10 µ. An increase, up to twentyfold, in the numbers of particles of these sizes was found in the effluent when compared to the particle distribution in the injectate. This suggested that aggregate fragmentation had occurred within the heart.