Abstract: The invention relates to a modified IMPDH polypeptide wherein the IMPDH polypeptide has a histidine tag and where the subdomain of the IMPDH polypeptide is modified so that the rate stability of the histidine-tagged, modified IMPDH polypeptide is maintained relative to the wild-type IMPDH polypeptide. The invention also relates to a method, nucleic acid molecules, vectors, and host cells for producing such a histidine-tagged, modified IMPDH polypeptide, and to kits comprising the histidine-tagged, modified IMPDH polypeptide.

Abstract: A homogeneous, non-competitive, double receptor agglutination assay for measuring immunosuppressant drugs is described. The assay employs at least two receptors wherein each receptor is specific for a separate binding site on the drug and wherein each receptor is bound to a detection particle. The immunosuppressant drug binds to the receptors and causes particle agglutination, which can be measured and correlated with the presence or amount of immunosuppressant drug in a sample.

Abstract: The invention relates to a modified IMPDH polypeptide wherein the IMPDH polypeptide has a histidine tag and where the subdomain of the IMPDH polypeptide is modified so that the rate stability of the histidine-tagged, modified IMPDH polypeptide is maintained relative to the wild-type IMPDH polypeptide. The invention also relates to a method, nucleic acid molecules, vectors, and host cells for producing such a histidine-tagged, modified IMPDH polypeptide, and to kits comprising the histidine-tagged, modified IMPDH polypeptide.

Abstract: The present invention provides a method for the measurement of an analyte in biological samples whereby an uncompetitive inhibitor is coupled to a ligand and utilized in a homogeneous assay. The analyte can be a drug or drug derivative, hormone, polypeptide, or oligonucleotide. The present invention also provides novel compounds, assay reagents and packaged kits useful for performing such measurements.

Abstract: The present invention provides a method for the enzymatic measurement of mycophenolic acid and other IMPDH inhibitors in biological samples.The present invention also provides assay reagents and packaged kits useful for performing enzymatic measurement of mycophenolic acid and other IMPDH inhibitors in biological samples.

Abstract: The invention provides sets of liquid reagents that afford calibration stability in an enzyme based spectrophotometric assay for the measurement of lactate in patient samples. The reagent sets include a lactate oxidase, a peroxidase, a hydrogen donor, an agent that substantially prevents ascorbic acid interference, and agent that substantially prevents bilirubin interference, a coupling agent, a buffer and, optionally, a preservative. The invention further provides methods for using the liquid reagent sets.

Abstract: Novel derivatives of procainamide and N-acetylprocainamide (NAPA) are disclosed having the following formula: ##STR1## wherein: X=hydrogen or acetyl;R.sub.1 =an alkyl group having 1 to 3 carbon atoms;m=an integer from 2 to 10;R.sub.2 =an alkyl, cycloalkyl or aryl group having 2 to 10 carbon atoms;Z=a poly(amino acid); andn=1 to p where p=MW of Z/1000.The derivatives include maleimide conjugates of proteins or poly(amino acids), enzymes, enzyme donor polypeptides and labeling substances. Novel activated hapten intermediates useful in the preparation of the conjugates and methods for synthesis of the hapten intermediates and derivatives are also disclosed.

Abstract: Cell separation compositions and associated methods effective for separating cells from various biological specimens such as blood are disclosed. The biological specimens are contacted with the cell separation compositions and centrifuged. The cells are separated based upon their buoyant density in the cell separation composition. The cell separation composition contains colloidal silica particles covalently linked to an organosilane having a non-ionic, hydrophilic group.

Abstract: Cell separation compositions and associated methods effective for separating cells from various biological specimens such as blood are disclosed. The biological specimens are contacted with the cell separation compositions and centrifuged. The cells are separated based upon their buoyant density in the cell separation composition. The cell separation composition contains colloidal silica particles covalently linked to an organosilane having a non-ionic, hydrophilic group.