Abstract: A method, kit, system and reagent for measuring low molecular weight heparin in a whole blood sample is provided which involves the use of a Factor Xa activator, such as Russell's Viper Venom, as the coagulation assay initiator.

Abstract: A method, kit, system and reagent for measuring low molecular weight heparin in a whole blood sample is provided which involves the use of a Factor Xa activator, such as Russell's Viper Venom, as the coagulation assay initiator.

Abstract: A method, kit, system and reagent for measuring low molecular weight heparin in a whole blood sample is provided which involves the use of a Factor Xa activator, such as Russell's Viper Venom, as the coagulation assay initiator.

Abstract: A method of performing a fibrinogen assay is provided using an assay reagent containing ecarin to give an assay that is insensitive to the presence of heparin and insensitive to hematocrit, while being useful as a point of care assay in both a dry chemistry and wet chemistry format.

Abstract: Chromogenic and fluorogenic substrates for .beta.-lactamase, methods for synthesis thereof and methods for detecting .beta.-lactamase in a sample are provided. The substrates are substantially colorless or substantially nonfluorescent .beta.-lactam compounds which include an electronegative leaving group. The leaving group comprises a carbamate, carbonate, thiocarbamate or thiocarbonate linkage and a fluorescent moiety or a moiety capable of producing a visually detectable colored product. Upon cleavage of the lactam ring by .beta.-lactamase, the leaving group is liberated and fluorescence or a colored product is produced.

Abstract: Methods for the detection, identification and/or quantitation of halogenated hydrocarbons in aqueous samples and kits for performing the methods are provided which provide high sensitivity and can provide high selectively for individual halogenated hydrocarbons such as TCE or THMs. An additional method is provided for the sensitive determination of TTHM in an aqueous sample. These methods use a general two step procedure of (1) extracting and concentrating the halogenated hydrocarbons from the aqueous sample and (2) subjecting the concentrated halogenated hydrocarbons to a modified Fujiwara reaction to provide chromophoric products which can be analyzed by absorption spectra of the resulting mixtures.

Abstract: Chromogenic and fluorogenic substrates for .beta.-lactamase, methods for synthesis thereof and methods for detecting .beta.-lactamase in a sample are provided. The substrates are substantially colorless or substantially nonfluorescent .beta.-lactam compounds which include an electronegative leaving group. The leaving group comprises a carbamate, carbonate, thiocarbamate or thiocarbonate linkage and a fluorescent moiety or a moiety capable of producing a visually detectable colored product. Upon cleavage of the lactam ring by .beta.-lactamase, the leaving group is liberated and fluorescence or a colored product is produced.

Abstract: Chromogenic and fluorogenic substrates for .beta.-lactamase, methods for synthesis thereof and methods for detecting .beta.-lactamase in a sample are provided. The substrates are substantially colorless or substantially nonfluorescent .beta.-lactam compounds which include an electronegative leaving group. The leaving group comprises a carbamate, carbonate, thiocarbamate or thiocarbonate linkage and a fluorescent moiety or a moiety capable of producing a visually detectable colored product. Upon cleavage of the lactam ring by .beta.-lactamase, the leaving group is liberated and fluorescence or a colored product is produced.

Abstract: The present invention relates to modified antibodies and fragments which display an increased affinity for antigen as compared to the affinity of unmodified antibody for antigen. The most preferred modification is the addition of a thiol group on the surface of the antibody such that a covalent bond forms between the antibody and antigen when they bind to one another.

Abstract: A method for enzyme immunoassay for a ligand suspected to be present in a liquid sample includes signal amplification by use of at least two enzymes and a blocked modulator for one of the enzymes. Ligand present in the liquid binds to an antiligand and an enzyme-labeled tracer. The resulting bound fraction is separated and the enzyme in the tracer removes the blocking group from the blocked modulator. The modulator activates or inhibits a second enzyme which catalyzes the conversion of a substrate to a product. The presence or absence of the ligand in the liquid is indicated by a signal, such as a color change or a rate of color change, associated with the product. The invention includes a new class of enzyme inhibitors and blocked inhibitors and a kit of materials useful for performing the method of the invention.

Abstract: Chromogenic and fluorogenic substrates for .beta.-lactamase, methods for synthesis thereof and methods for detecting .beta.-lactamase in a sample are provided. The substrates are substantially colorless or substantially nonfluorescent .beta.-lactam compounds which include an electronegative leaving group. The leaving group comprises a carbamate, carbonate, thiocarbamate or thiocarbonate linkage and a fluorescent moiety or a moiety capable of producing a visually detectable colored product. Upon cleavage of the lactam ring by .beta.-lactamase, the leaving group is liberated and fluorescence or a colored product is produced.

Abstract: A fluorogenic substrate for tryptophanase useful for identifying an unknown microorganism is a fluorescent dye linked to an amino acid by a carbamate or thiocarbamate group. In preferred substrates, the dye is fluorescein or 7-amino-4-methyl coumarin and the amino acid linked thereto is cysteine, threonine or serine.

Abstract: A novel fluorescent dye, PUR-1, having the structural formula ##STR1## is disclosed that will preferentially stain nucleic acids.

Abstract: A method for enzyme immunoassay for a ligand suspected to be present in a liquid sample includes signal amplification by use of at least two hydrolases and a blocked fluoroketone for one of the hydrolases. Ligand present in the liquid binds to an antiligand and a hydrolase-labeled tracer. The resulting bound fraction is separated and the hydrolase in the tracer removes the blocking group from the blocked fluoroketone. The fluoroketone activates or inhibits a second hydrolase which catalyzes the conversion of a substrate to a product. The presence or absence of the ligand in the liquid is indicated by a signal, such as a color change or a rate of color change, associated with the product. The invention includes a new class of hydrolase inhibitors and blocked fluoroketones and a kit of materials useful for performing the method of the invention.

Abstract: A method for immunoassay of an analyte in a fluid includes contacting the analyte with an antianalyte to give a bound fraction. The bound fraction activates the first component of complement whereby a substrate present in the fluid is modulated to provide a detectable signal. The signal may be detected to establish the presence or absence of the analyte in the fluid, or it may be quantitatively measured to determine the concentration of the analyte in the fluid. The invention includes a kit of materials useful in performing the method of the invention.