A pattern-recognition technique has been established using a new class or orthogonal polynomials, developed by Cohen. The method is based on a supervised learning approach, and allows classification of data into two or more categories. In this paper, the usefulness of the method in the analysis of chromatographic data is illustrated by its application to the diagnosis of bacterial infection of patients with liver disorders by use of chromatograms obtained from ascitic fluid withdrawn from the patients.

Spleens of mice which were immunized with sheep or horse red blood cells contained a population of hemolysin-producing cells that could be detected with the Jerne plaque assay. Plaque-forming cells (PFCs) were detected up to 3 days after adoptive transfer into the peritoneal cavities of recipient histoincompatible mice. When the recipient mice were sensitized by i.p. injection of cells syngeneic with the donor of the transferred cells at least 72 hr prior to transfer, the hemolytic plaque response of the transferred cells was largely suppressed. Early suppression was limited to the peritoneal cavity; allografted spleen cells were consistently detected in the spleens of recipient mice up to 3 days after transfer whether sensitized or not. The suppression response was specific for the allospecificities against which recipient mice were sensitized. The response was also proportional to the dose of sensitizing cells between 0.1 and 5 X 106 cells and was linear with the log10 of the cell number used for sensitization plotted against log10 number of plaques/mouse. When two populations of spleen cells, labeled by immunization to horse or sheep red blood cells, respectively, from non-cross reacting target allotypes were individually transferred to unsensitized recipients, each population was detected by its independent label. If recipient mice were sensitized to either allotype, the cells with the non-cross reacting alloantigen (the innocent bystanders) were also suppressed when mixed with the specific target cells.

Summary Ferrocene is representative of an unique class of compounds, the metallocenes, which incorporate a heavy metal atom in a pseudo-aromatic cyclopentadienyl ring system of benzene-like stabillity. Two ferrocenyl groups per polypeptide chain slightly enhance the amount of antibody elicited, but only a small amount of the antibody is directed at the ferrocenyl group. At this level, ferrocene is useful as a label for metabolic studies. Larger amounts of ferrocene (10 to 16) show strong hapten activity with up to 70% of the antibody directed at the ferrocenyl group. The ferrocene-antiferrocene reaction can be inhibited by ferrocenyl-acetic acid. In addition, the heavily labelled molecules elicit larger amounts of antibody than the parent polymer or the derivative containing 2 ferrocenes. The ability of ferrocene to enhance immunogenicity reflects behavior similar to that of the aromatic amino acids and cyclohexylalanine. Ferrocene may be even more unique in this regard, because it enhances immunogenicity in a polypeptide which contains 6% tyrosine and is already a good immunogen. The metallocenes, of which ferrocene is a prototype, have three distinct advantages for use in metabolic studies: they incorporate radioactive heavy metal atoms with relatively long half-lives; they are biologically stable and probably cannot be reutilized by the animal in any significant amount; and they may become electron-dense if short polymers of the metallocenes are attached to the polypeptide chain.

The metallocenes, of which ferrocene is a prototype, have three distinct advantages for use in metabolic studies: they incorporate radioactive heavy metal atoms with relatively long half-lives; they are biologically stable and probably cannot be reutilized by the animal in any significant amount; and they may become electron-dense if short polymers of the metallocenes are attached to the polypeptide chain.