Milton Segalove

Turbidimetric determination of proteins with sulfosalicylic and trichloracetic acids.

Summary The turbidity produced by addition of sulfosalicylic acid to a solution of a mixture of proteins is correlated with the A/ G ratio. No correlation is apparent when trichloracetic acid is employed. It is suggested, therefore, that trichloracetic acid should supplant sulfosalicylic acid in turbidi-metric methods for the determination of protein.

Determination of Ceruloplasmin Oxidase in Serum

Summary A method for determination of ceruloplasmin in serum is presented in which rate of oxidation of p-phenylenediamine is measured spectrophotometrically or photometrically. Correction for catalytic oxidation by free metals present is made by reading the test against a serum blank in which enzymatic activity is inhibited by azide. The effects of pH and temperature on the reaction have been investigated and normal values obtained by our method. Ethylenediaminetetraacetate significantly inhibits enzymatic oxidase activity of serum.

Determination of α-amino acid nitrogen in urine.

Summary A modification of the photometric copper phosphate method for determination of α-amino acid nitrogen in urine has been presented. A comparison of results obtained in urines by the copper phosphate, naphthoquinone and gasometric-ninhydrin methods indicates that the specificity of the copper phosphate and naphthoquinone methods is materially improved by preliminary isolation of the amino acids on an ion exchange column.

Effect of Penicillin on Growth and Toxin Production of Enterotoxigenic Staphylococci.

Summary The natural resistance of 15 enterotoxic strains of staphylococci to penicillin was found to range from 0.05 to 500 units per ml. Production of staphylococcal hemolysins, lethal factor and dermonecrotoxin, but not of enterotoxin, was inhibited by growing selected naturally and artificially resistant strains in Amigen liquid medium containing sublethal concentrations of penicillin. Inhibition was not observed in similar experiments using semisolid Amigen and veal infusion media.