Syntex (u.s.a.) Inc.

Richard D Armenta

Ian Gibbons

Edwin F Ullman

John D Olson

A method is disclosed for reducing the oxygen content of a medium in which are present cells, usually anaerobic microorganisms, to extend the time during which the cells remain viable. The method comprises having in fluid contact with the aqueous medium an effective amount of an oxidase and substrate for the oxidase. The oxidase and substrate for the oxidase in an aqueous medium can be in fluid, e.g., air, contact with a separately contained aqueous medium in which the cells are present. Alternatively, the cells can be present in the same aqueous medium as the oxidase and substrate for the oxidase. The aqueous medium containing the oxidase and the substrate for the oxidase can further contain a hydrogen peroxide scavenger in an effective amount. A composition in accordance with the invention comprises in a liquid medium viable cells, such as anaerobic microorganisms, an oxidase and its substrate in an amount sufficient to retain the viability of the cells, and a hydrogen peroxide scavenger in an amount sufficient to reduce the level of hydrogen peroxide generated by the oxidase. The method of the invention has particular application in transport media used for transporting microbiological specimens.

Method and compositions for protecting anerobic microorganisms

Background interference which disrupts the measurement of an analyte in enzyme immunoassays with samples is substantially diminished. In accordance with one embodiment of the invention, the serum sample is treated with a sufficient amount of a peracid compound, either organic or inorganic, for a time and under conditions sufficient to reduce or eliminate background interference contributed by serum components other than analyte. The peracid compound is readily quenched, without adversely affecting the assay compositions. In another embodiment of the invention a liqand for the interfering component of the sample, such as unconjugated enzyme which is inactive but antigenic, is mixed with the sample to be analyzed. The presence of the liqand substantially reduces or eliminates background interference from components of the sample other than analyte.

Reducing background interference activity in enzyme-label immunoassays

An improved immunoassay for determining the presence of an analyte in a serum sample and conjugates therefor are described. The known method comprises combining the sample with a conjugate of the analyte and an enzyme and with a receptor for analyte, and determining the presence of analyte in the sample from the effect that the sample has on the enzymatic activity when compared to the enzymatic activity in the absence of analyte or in the presence of known amounts of analyte. The present invention resides in the conjugation to the enzyme label of a label protectant which allows modulation of the enzymatic activity to occur and minimizes background interference between the enzyme label and the sample, which would alter the enzymatic activity.

Immunoassays employing protected labels

Composition and method are provided for enzyme immunoassays for high molecular weight proteins, such as ferritin. An enzyme is conjugated to the high molecular weight protein through a specific linking group. Usually, on the average, about 2 to 10 enzyme molecules are bonded to each protein molecule. In an assay, the conjugate competes with an unknown sample for receptor and the resulting enzymatic activity is compared to a standard for a determination of the presence and amount of protein in the unknown.

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Mountain View, CA, United States of America

Richard D Armenta