Because of their structural similarity to dialysis membranes, six plasma separator membranes were evaluated for the ability to activate complement, as judged by immunoconversion of the third component of complement in crossed immunoelectrophoresis. A polysulfone and two cellulose acetate membranes were relatively strong alternative pathway activators. Polypropylene, poly[vinylidine fluoride] and polyvinyl-chloride derivative membranes were weak activators in some sera. Membrane activation was inhibited in citrate-anticoagulated but not in heparin-anticoagulated plasma. The results of such in vitro screening should be of value in selecting materials and anticoagulation regimens for membrane plasma separators.
A group of modifications, including a reservoir bag in the return circuit, has been devised to allow single needle plateletpheresis with the COBE Spectra. We compared the number and quality of platelets collected from 10 subjects in paired donations with single and dual needle protocols. There was no evidence of hemolysis with either protocol. Mean (+/- SD) platelet yields were 3.61 +/- 1.47 x 10(11) with two needles and 3.31 +/- 1.31 x 10(11) with the single needle procedure (P = .13). Mean leukocyte levels (standard manual counting chamber) were 1.0 +/- 1.7 x 10(7) and 1.2 +/- 1.0 x 10(7), respectively (p = .78). pH values during storage were acceptable in both groups of concentrates, and there were no significant differences between the single needle and dual needle concentrates in morphology scores or beta-thromboglobulin levels at 0, 1, 3, or 5 days of storage. Thus the single needle modification produced platelets that were comparable in quantity and quality to those from the standard dual needle plateletpheresis protocol.
The technique of crossed immunoelectrophoresis (X-IEP) has been used to quantify free monoclonal light chains (LC) directly in the serum of patients with light chain disease, without preliminary gel or membrane filtration of serum to separate whole immunoglobulin. LC concentration is proportional to the area under an immunoprecipitin peak formed by LC in the patient's serum and an anti-LC antibody of appropriate specificity. Light chains of beta electrophoretic mobility can be processed in the standard X-IEP technique at pH 8.6. Light chains of gamma mobility must be processed in a modified technique using a pH of 5.0 and a carbamylated antiserum in the second dimension gel. Dose response curves obtained from the method in serial dilution experiments with sera from 18 patients gave correlation coefficients greater than or equal to 0.99. Replicate measurements of absolute LC concentration on the same specimens were within +/- 10%. The method can also detect polymerized light chains. Serum light chain levels were measured during the course of plasmapheresis therapy in three patients with light chain disease and renal failure. Light chain levels were shown to fall after plasmapheresis and to rise rather rapidly in the interval between treatments.
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