Abstract: Assays and reagents are provided for the measurement of components that are involved in either enzyme-catalyzed degradation of a substrate, such as in fibrinogenolysis or fibrinolysis; or enzyme-catalyzed polymerization of a substrate, such as in fibrinogen polymerization into fibrin. The method involves using a fluorescent-labeled substrate in an enzyme-catalyzed reaction, and measurement of the component's effects on the fluorescence emission of the enzyme-catalyzed reaction such as quenching or dequenching, as a measure of the component's activity.

Abstract: Specific binding ligands can be detected with an assay which utilizes an immobilized receptor for the ligand, a reporter enzyme, an inhibitor antibody and an anti-inhibitor antibody. Both antibodies are specific for the reporter enzyme. The inhibitor antibody effectively shuts down the activity of the reporter enzyme when it is complexed thereto. The anti-inhibitor antibody binds to the reporter enzyme, does not affect the enzymatic activity, but prevents the binding of the inhibitor enzyme. This assay provides a direct correlation of the target specific binding ligand to the signal generated without the use of separation or wash steps.

Abstract: Methods for determining the presence of a ligand in a sample suspected to contain the ligand are provided, along with apparatus suitable for performing the methods. The methods depend upon a color visualization indicating the ligand's presence or absence in the sample. Preferred methods comprise contacting the sample with colored particles which bear on their surface a receptor specific for the ligand, passing the sample/particle mixture through a filter, and then analyzing the color of the filtrate. The presence of ligand in the sample is established where the color of the filtrate is substantially different from the color of the receptor-bearing particles.

Abstract: A method of identifying compounds that effect integrin activation in intact cells is provided.

Abstract: A non-invasive method to measure total body tissue iron stores comprising recovering iron released from total ferritin contained in a body fluid sample derived from a host, measuring the ferritin-iron in the total ferritin and thereby determining total body tissue iron stores. Such an assay is utilized for diagnosing negative iron balance as well as positive iron balance, wherein the latter promotes cancer, coronary artery disease, atherosclerosis, and hepatic failure among other diseases, as well as the susceptibility to such diseases.

Abstract: A flow cytometric method for determining procoagulant platelet-derived microparticles in whole blood is described.

Abstract: A method and apparatus are provided for selecting and analyzing a subpopulation of cells or cell objects for a certain parameter such as DNA using image analysis means. The cells are first stained with an alkaline phosphatase technique including a monoclonal antibody specific to a protein in at least one of the cell's cytoplasm or on a cell membrane, thereby marking any cells including the protein as to type. A second staining of the DNA in the nucleus is accomplished by a Feulgen technique that destroys the cell cytoplasm. After the staining and marking, the cells may then be gated using the image analysis means on the visual parameter such as colored DNA or colored antigen into a subpopulation that is to be measured. The selected cells may then be examined by digital image processing and measured for a parameter such as a true actual measurement of DNA in picograms. A quantitation of the measured parameter may be generated and provided.

Abstract: This invention is directed to the novel assay methods utilizing nucleophilic polysubstituted aryl acridinium ester conjugates as the tracers. Conjugates prepared by covalent coupling of novel nucleophilic polysubstituted aryl acridinium esters with biological compounds including small organic molecules such as Vitamin B12, folate, cortisol, estradiol, and thromboxane B2, were found useful in the development of highly sensitive assays for the analytes of diagnostic interest.

Abstract: A method for the non-radioactive determination of circulating red cell volume, total blood volume and red cell survival. Red blood cells are biotinylated and injected into the subject for dilution in the subjects total blood volume. A diluted sample is extracted and incubated with a label, either a radionuclide or a fluorescent moiety complexed with avidin or streptavidin. Detection of the label, as for example by gamma counting in the case of a radionuclide or fluorescence activated cell sorting in the case of a fluorescent moiety, allows calculation of the red cell volume and therefrom, total blood volume. Sequential measurements are possible with this method. Aspects of the method include enhanced biotin labeling and separation of cells by density gradient means.

Abstract: The present invention relates to a diagnostic assay utilizing the lipid associated membrane proteins of mycoplasmas to detect the presence of species-specific mycoplasma antibodies. The sensitive assay is useful for the detection and differentiation of mycoplasma antibodies specific for individual species in biological samples from humans and animals, and exhibits virtually no cross-reactivity between different mycoplasma species.

Abstract: A method is provided for detecting an analyte of interest in a sample. The method involves binding the analyte to the surface of a substrate through a biotin-biotin binding protein interaction, contacting the surface-bound analyte with a quantitatively detectable analyte-binding moiety that binds thereto, measuring the quantity of detectable moiety bound to the substrate surface and deriving therefrom the quantity of analyte in solution. A preferred use for the present method is in conjunction with a piezoelectric surface transverse wave device. Novel reagents useful for carrying out the inventive method are provided as well.

Abstract: The present invention relates to a method employing at least one luminescent tracer compound and a luminescent compound used as an internal reference, which, when exposed to the same excitation wavelength, are capable of emitting at difference wavelengths, .lambda..sub.2 and .lambda..sub.1 respectively, either by direct luminescence or by the induction of a luminescent emission, and correcting the measurement of the luminescence emitted by the tracer compound at wavelength .lambda..sub.2 on the basis of the measurement of the luminescence emitted by the reference compound at wavelength .lambda.1.

Abstract: A synthetic strategy for the creation of large scale chemical diversity is claimed. Solid-phase chemistry, photolabile protecting groups, and photolithography are used to achieve light-directed spatially-addressable parallel chemical synthesis of an array of polymers that are based on a target polymer. The array includes systematically substituted versions of the target polymer.

Abstract: A method of determining an analyte in the gaseous or vapour phase and in which a bioreceptor or biomimic is retained at an electrode. The bioreceptor or biomimic is preferably retained at a support at the electrode which comprises a solid or gel matrix of an electrolyte, especially organic salt electrolytes. Electrochemical detection of analytes in this way has several advantages over existing methods which rely on solution monitoring. For example gas sensors can be prepared for monitoring an analyte by the occurrence of a reaction with a bioreceptor or biomimic, in addition to monitoring the presence of toxins due to inhibition of the bioreceptor or biomimic reaction. Furthermore, the invention enables gas or vapour analyte monitoring with increased sensitivity and speed and greater stability of the sensors can be achieved. The invention also relates to novel media for carrying out bioelectrochemical reactions.

Abstract: An improved one-step immunochromatographic assay which involves the binding of a predetermined amount of analyte to an antibody, enabling the control of the assay sensitivity, is disclosed. The system is especially useful as a controlled sensitivity fecal occult blood assay. Antibodies to a desired analyte, present at a predetermined concentration, are deposited on the sample pad of the reaction unit. The antibody binds analyte present in the sample, up to a threshold amount. Analyte which is present in the sample at a level above the threshold amount proceeds unbound through the sample pad and onto a membrane, where it reacts with an antibody-coated latex and a second, immobilized antibody to generate a positive signal.

Abstract: A dry immunoassay analytical element, for assaying a ligand, comprising a support bearing:(a) a labeled ligand zone;(b) a spreading zone; and(c) a receptor zone containing a fixed concentration of an immobilized receptor for the ligand and the labeled ligand and the receptor is covalently bonded to polymeric beads having a diameter in the range of 0.1 to 5 .mu.m;characterized in that the element contains a compound containing a vanadium IV (V.sup.+4) ion and the zones can be in the same or separate layers.

Abstract: A method is disclosed for detecting abnormal epitope expression of protein molecules by immunocapturing a constant number of protein molecules from a test and a reference sample using a limited amount of capturing antibodies, saturating them with its corresponding protein from the test and reference samples to provide a constant, known amount of the immobilized protein for comparison, labelling an epitope on the immobilized protein by means of a labelled probing antibody specifically reactive with the epitope and correlating any difference in labelling between the test and the reference sample to the absence or modification of the epitope in the protein of the test sample.

Abstract: A method for synthesizing and screening oligonucleotides on a solid substrate. The method provides for the irradiation of a first predefined region of a substrate comprising immobilized nucleotides on its surface, without irradiation of a second predefined region of the substrate. The irradiation step removes a protecting group from the immobilized nucleotides. The substrate is contacted with a first nucleotide to couple the nucleotide to the immobilized nucleotides in the first predefined region without coupling in the second predefined region. At least a part of the first predefined region and at least a part of the second predefined region are subjected to further irradiation. The substrate is contacted with a second nucleotide, which couples to the immobilized nucleotides in at least part of the first and at least part of the second predefined regions. By repeating these steps, an array of diverse oligonucleotides is formed on the substrate.

Abstract: This invention relates to a method for the isolation of trophoblast (placental) cells from the blood of a pregnant mammal so as to provide the essential starting material, namely cells derived from the fetus, to enable genetic and/or biochemical information about the fetus to be obtained. In particular, this invention relates to the use of monoclonal antibodies specific for membrane protein markers on mammalian trophoblasts to isolate trophoblast cells from maternal blood. These cells may then be used to obtain fetal genetic and/or biochemical information early in pregnancy. The present invention is particularly relevant for detecting human fetal abnormalities.

Abstract: An immunoassay method for the detection or quantitation of an analyte suspected of being in a solution comprising: (a) combining said specimen, a first binding component, insoluble particles, and second binding component labelled with a signal generating material in a solid phase retention and separation apparatus having a sufficient pore size such that said particles are trapped within said filter yet permitting rapid passage of fluid therethrough in such a manner that an immunological reaction occurs if analyte is present in said specimen, resulting in the formation of an immunocomplex of insolublized first binding component:analyte:second labelled binding component on or within said filter means; (b) separating bound from unbound material; and (c) determining the presence and/or amount of signal produced which is correlative with the amount of analyte present in the solution.