The application of sodium deoxycholate and Sephacryl-200 for the delipidation and separation of high density lipoprotein.

A method to remove lipids from human plasma high-density lipoprotein (HDL) was developed. The procedure required column chromatography on Sephacryl-200 in the presence of the bile salt sodium deoxycholate. The lipid free protein obtained retained the immunological properties of the native HDL.

Variation in Counts, Enterotoxin Levels and TNase in Swiss-Type Cheese Contaminated with Staphylococcus aureus.

In 1977, a number of staphylococcal intoxications occurred as a result of several lots of Swiss-type cheese being contaminated with Staphylococcus aureus . Blocks of cheese representing 59 of the recalled lots manufactured between January 5 and April 25, 1977, were examined for S. aureus counts and for staphylococcal thermonuclease (TNase), enterotoxin and pH.

The use of polyethylene glycol in radioimmunoassay of staphylococcal enterotoxins.

The double-antibody radioimmunoassay of enterotoxins A, B, and C was modified by the addition of aqueous polyethylene glycol which precipitated double-antibody bound staphylococcal enterotoxins with little or no precipitation of free enterotoxin. The precipitate formed appeared as a thin coating at the bottom of the test tube and was not removed by aspiration. The procedure obviates the need for normal rabbit serum and for an additional wash of the precipitate.

Double-antibody radioimmunoassay for staphylococcal enterotoxins A and B.

A sensitive double-antibody radioimmunoassay for staphylococcal enterotoxins A and B is described. The separation of the primary antigen-antibody complex of enterotoxin A and B was achieved with an anti-rabbit gamma globulin from goats. Radioiodinated aggregate fractions of staphylococcal enterotoxins exhibited reduced immunological activity and showed little competition with non-radioactive exterotoxin.

Detection of staphylococcal enterotoxin in gastric juice.

The gastric juice of a patient showing symptoms of staphylococcal food poisoning was examined by a radioimmunoassay for the presence of enterotoxins. Assays gave markedly higher results at 35 degrees than at 5 degrees. The source for this discrepancy was attributed to interference due to trypsin activity on the basis of (1) the demonstration of hydrolysis of p-toluenesulfonyl-L-arginine methyl ester by the specimen, (2) inhibition of this activity by trypsin inhibitor from lima bean, and (3) lowered values produced for enterotoxins in gastric juice when the inhibitor was included in the assay system.