Nicholas Catsimpoolas

Characterization of feline omentum lipids

Feline omental lipid extracts, previously reported to be angiogenic in the cornea of rabbits, were fractionated and the major lipid components characterized. Approximately 97% of the chloroform/methanol extract consisted of triglycerides containing primarily 16∶0, 18∶0, 18∶1 and 18∶2 fatty acids. Trace quantities of free fatty acids, cholesterol, di- and monoglycerides were also detected. The phospholipid fraction, obtained by solvent partition and Unisil column chromatography and characterized by high performance liquid chromatography (HPLC)-mass spectrometry, was found to consist of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine and phosphatidylserine. The neutral glycolipids, isolated by solvent partition and Unisil column chromatography and identified by high performance thin layer chromatography and HPLC of their perbenzoylated derivatives, were found to consist of glucosyl- and galactosylceramides, galabiosylceramide, lactosylceramide, globotriaosylceramide and globotetraosylceramide. The complex glycolipid fraction, obtained from Folch upper phase solvent partition, was found to consist primarily of Forssman glycolipid and gangliosides GM3 and GD3. Smaller amounts of GM1 and other unidentified gangliosides were also present.

Measurement of the distribution of indium-111 on human plasma proteins using immunoprecipitation.

The distribution of radioactivity on plasma proteins labeled by addition of [111In]oxine to citrated plasma was investigated. Analyses of plasma proteins separated on Sephadex G-200 columns showed that 23-36% of the 111In was associated with proteins with molecular weight greater than 200,000 daltons and the remaining 111In was associated with proteins with molecular weight less than 100,000 daltons, presumably transferrin. Affinity chromatography experiments showed that less than 2% of the radioactivity was associated with albumin. Further identification of the labeled proteins and quantitation of associated radioactivity was performed by precipitating specific proteins with antibodies. These studies showed that the 111In was distributed on transferrin (54-76%), fibrinogen (11-24%), IgM (8-20%), C3 (10-21%), and haptoglobin (3-8%). 111In associated with fibrinogen, IgM, and haptoglobin was over-estimated in some experiments due to binding of 111In-labeled C3 to the antigen-antibody precipitates.

Sedimentation Behavior of Activated Human Granulocytes: Aggregation and Volume Effects

Human peripheral blood granulocytes (PMNs) obtained from normal adults were studied by an analytical gravity sedimentation system. Exposure of PMNs to endotoxin-activated serum (EAS) in a Ficoll density gradient containing Hank’s balanced salt solution with calcium and magnesium produced significantly different sedimentation patterns compared to those from granulocytes exposed to normal serum under the same conditions. Experiments were performed to determine whether changes in granulocyte density, volume, shape, or aggregation were responsible for the sedimentation pattern of granulocytes exposed to EAS. The altered gravity sedimentation behavior of endotoxin-activated granulocytes was abolished when calcium and magnesium were not present in the Ficoll density gradient. Granulocyte aggregation was inhibited by the absence of calcium and magnesium in the medium during granulocyte stimulation, whereas the changes in granulocyte shape and volume associated with granulocyte stimulation were not affected. The data indicate that the altered granulocyte sedimentation pattern in the presence of EAS and calcium and magnesium was produced by granulocyte aggregation and not by changes in granulocyte volume or shape.