Purified human spleen ferritin was labelled with 125I. On Sepharose 6-B gel filtration four species of labelled products were separated: a component with a higher molecular weight than ferritin; a component which is eluted in the same volume as unlabelled ferritin; and two labelled compounds with molecular weights lower than ferritin. When these labelled materials were used in a double antibody...

A simple, rapid, precise radioimmunoassay for total unsulfate species of lithocholate (lithocholyglycine, lithocholyltaurine, and lithocholate) in serum is described. Antiserum was raised in rabbits by injection of lithocholylglycine coupled to bovine serum albumin (prepared by a carbodiimide method) and emulsified in complete Freund's adjuvant; antisera capable of measuring 40-120 pmol at 1:40...

We describe a radioimmunoassay for measuring clindamycin in serum extracts that is more accurate than the microbiological assay because of the minimal response of the matabolite, N-demethylclindamycin. The assay is not affected by the presence of other antiobiotics. As described it is as sensitive as the microbiological assay, but can be made more sensitive.