Abstract: Compositions and methods are disclosed which enhance the microscopic observation and analysis of biological entities such as cells, bacteria and viruses by eliminating interfering magnetic clusters created by naturally occurring aggregators of colloidal magnetic particles. Additionally means for significantly enhancing the magnetic isolation of low antigen density target cells from biological samples are disclosed.

Abstract: In a homogeneous immunoassay, fluorophore-conjugated lipopolysaccharide derived bacterial antigens are reacted with antibodies specific for the antigens. Quantitative detection of the formation of an immune complex is obtained by measuring the change in fluorescence polarization after complex formation. The reaction occurs quickly (less than two minutes to equilibrium), and involves the addition of only one reagent to a diluted serum specimen. The absence of a solid phase separation step eliminates false positive results and increases throughput.

Abstract: A method for determining the affinity between binding partners, or a property of one of the binding partners dependent on the affinity, comprising the steps of: (i) contacting the binding partners, one of which is immobilised on a surface; (ii) oscillating the surface at increasing amplitude; and (iii) detecting a dissociation event. An analogous method can be used to separate a target analyte from a composition. The subject invention also pertains to an apparatus for determining the affinity between binding partners, and comprises: a surface (10) having one binding partner (16) immobilised thereon; means for oscillating the surface at increasing amplitude; and a device (14, 15) for detecting a dissociation event.

Abstract: The present invention provides a method for identifying a test compound that binds to a target species. The method includes: incubating at least one test mixture under isothermal denaturing conditions, each test mixture comprising at least one test compound, and at least one target species, wherein the isothermal denaturing conditions are effective to cause at least a portion of the target species to denature to a measurable extent; detecting a denaturation signal of each target species in the presence of the at least one test compound by a change in the diffusion properties of the target molecule using fluorescence correlation spectroscopy; and comparing the denaturation signal of each target species in the presence of at least one test compound with a denaturation signal of the same target species in the absence of the at least one test compound under the same isothermal denaturing conditions.

Abstract: Methods for measuring the concentration of an analyte in a sample are provided. The sample is contacted with a receptor molecule having binding sites for the analyte which is labeled with a first marker under conditions whereby only a small fraction of the binding sites on the receptor become occupied by the analyte. The receptor having fractionally occupied binding sites is then back-titrated via a back titration technique which includes a second marker different from the first, and the relative strengths of the two signals produced by the markers are measured thereby providing a value representative of the fractional occupancy of the binding sites on the receptor molecule by the analyte. This value is compared with one or more corresponding values obtained in the same way using one or more standard liquid samples of known analyte concentration.

Abstract: The present invention provides methods of harvesting rare cells from blood products and/or obtaining products of the rare cells. The method includes contacting a blood product containing rare cells with a porous medium, and selectively retaining rare cells of interest on the porous medium. The porous medium can be contacted with an elution fluid wherein a population of the rare cells is eluted from the porous medium. Rare cells selectively retained on the porous medium can be cultured on the porous medium, and products of the rare cells can be obtained.

Abstract: A sensor and method for detecting biological and chemical agents comprising metal interdigitized electrodes coated with hybrid polymer-based conducting film and an instrument for applying electrical voltage to the electrodes and registering the change in electrical current. The hybrid film also comprises indicator biomolecules encapsulated within the film or attached to it. The bioindicator molecules preferably comprise enzyme acetylcholinesterase. When these indicator biomolecules come in a contact with a pathogen, chemical and/or morphological changes occur in the film and electrical current flowing through the electrodes is modulated. The pathogen comprise inhibitors of enzymes, preferably organophosphates, thiophosphates or phosphonates. The change in current indicates the presence of a biological and chemical agent and is registered.

Abstract: The invention concerns a method for the determination of an analyte in which rheumatoid factors or rheumatoid-factor-like substances are added as an interference reducing reagent to reduce of avoid a hook effect. The invention in addition concerns suitable reagent kits for carrying out the method.

Abstract: Disclosed are fluorescent energy transfer dyes which are capable of moving between a more stacked configuration to exhibit fluorescent quenching and a more spaced configuration to exhibit fluorescence can be conjugated to a peptide epitope for use in the detection of an unknown antibody in bulk solution. The resulting labeled peptide reagent can be used in an immunoassay procedure by placing it in bulk solution along with the unknown antibody to be detected. When the antibody binds to the peptide epitope, the pair of dyes carried by the peptide epitope will have their configuration altered from a stacked to an unstacked configuration and will exhibit a fluorescent increase in response thereto.

Abstract: A homogeneous assay for determining the fumonisin content in grains uses the technique of fluorescence polarization. A grain extract is prepared by shaking a crushed grain sample with a solvent. A mixture is prepared by combining the grain extract with a tracer and with monoclonal antibodies specific to fumonisin. The tracer is able to bind to the monoclonal antibodies to produce a detectable change in fluorescence polarization. The tracer is prepared by conjugating fumonisin to a suitable fluorophore. The fluorescence polarization of the mixture is measured. The fumonisin concentration of the mixture may be calculated using a standard curve obtained by measuring the fluorescence polarization of a series of fumonisin solutions of known concentration.

Abstract: A method of detecting cardiac ischemia by detecting elevated levels of serum free fatty acids in serum unbound to serum albumin (FFAU) compared to an average FFAU level in individuals without cardiac ischemia, wherein the detection method uses a free fatty acid binding protein derivatized with a fluorescent moiety, is disclosed.

Abstract: The present invention is directed to a fluorescence polarization immunoassay for barbiturates, to the various components needed for preparing and carrying out such an assay, and to methods of making these components. Specifically, tracers, immunogens and antibodies are disclosed, as well as methods for preparing them and a reagent kit containing them. The tracers and the immunogens are made from substituted barbiturate compounds. A fluorescein moiety is included in the tracer, while a poly(amino acid) forms a part of the immunogen. The assay is conducted by measuring the degree of polarization retention of plane—polarized light that has been passed through a sample containing antiserum and tracer.

Abstract: An assay apparatus includes a cell with a working electrode and a sonicating device structurally coupled to the cell for sonication the contents of the cell.

Abstract: A method for detecting the presence of a target analyte comprising binding a target analyte to a binding ligand comprising at least a first electron donor moiety and a second electron acceptor moiety; and detecting the electron transfer between the donor and acceptor, wherein there is a change in the amount of electron transfer between the donor and acceptor as a result of altering the structured state of the donor and acceptor caused by a conformational change in the binding ligand upon binding of the target ligand.

Abstract: The invention concerns the stabilization and amplification of electrochemiluminescence signals in detection methods.

Abstract: A fluorescence polarization assay for Equine Infectious Anemia Virus utilizes a short peptide reagent probe derived from a conserved immunodominant region of gp45. The probe is N-terminally labeled, preferably with 6-carboxyfluorescein, and purified by HPLC, which reacts in a homogenous assay with anti-EIAV antibodies contained in the serum of field infected horses and ponies. The assay has a sensitivity of about 90 percent with a specificity approaching 100 percent.

Abstract: A method and compositions for the detection and/or quantification of an analyte through the use of a plurality of labeled probes, with two or more said probes targeted to different regions of said analyte. In specific embodiments, the labels are separately distinguishable, and/or are present at different specific activities on the labels.

Abstract: Methods and materials for scintillation assays are disclosed. The scintillation assays rely on differences in general molecular property-based binding interactions, such as charge or hydrophobicity, to localize a radioactive substance near a scintillating material, stimulating scintillation. They are thus described as a direct adsorption scintillation assay (DASA) to distinguish them from the scintillation proximity assay (SPA). The assays are more convenient and inexpensive to implement than SPAs, which rely on specific binding of ligand-receptor pairs, antibody-antigen pairs, or other binding partners which rely on the precise and specific structural complementarity of the partners. The assays can be employed for studying enzymatic reactions, such as those involved in the synthesis of Mur-pentapeptide. The assays are readily adaptable to high throughput screening for use in conjunction with combinatorial libraries of compounds.

Abstract: A biphase immunoassay method is provided in which a water immiscible liquid is qualitatively or quantitatively measured by mixing a sample of the water immiscible liquid with an aqueous solution containing a specific binding partner of the analyte. Binding occurs at or across the interface between the respective liquids and the degree of association of the analyte with its binding partner is dependent upon the concentration ratio rather than absolute quantities. The degree of association may be determined and used to determine the presence and/or concentration of analyte in the sample.

Abstract: Compositions are disclosed comprising (a) a metal chelate wherein the metal is selected from the group consisting of europium, terbium, dysprosium, samarium osmium and ruthenium in at least a hexacoordinated state and (b) a compound having a double bond substituted with two aryl groups, an oxygen atom and an atom selected from the group consisting of oxygen, sulfur and nitrogen wherein one of the aryl groups is electron donating with respect to the other. Such composition is preferably incorporated in a latex particulate material. Methods and kits are also disclosed for determining an analyte in a medium suspected of containing the analyte. The methods and kits employ as one component a composition as described above.

Abstract: An apparatus for performing a binding assay for an analyte of interest in a sample based upon measurement of clectrochemiluminescence at an electrode surface comprising: (a) a cell defining a sample; (b) an electrode adjacent a portion of the sample containing volume; (c) a voltage control device for impressing electrochemical energy upon the electrode sufficient to generate luminescence; (d) means for magnetically collecting particles along the electrode surface; and (e) a light detection device for measuring the luminescence.

Abstract: Receptors are disclosed that are antibodies that exhibit a binding affinity for an immune complex of a monoepitopic antigen and an antibody for such antigen that is substantially greater than the binding affinity for the monoepitopic antigen or the antibody for the monoepitopic antigen apart from the immune complex. Normally, the monoepitopic antigen has a molecular weight less than 1500 and is an organic compound. The antibodies of the present invention find use in a method for determining a monoepitopic antigen in a sample suspected of containing such antigen. The method comprises forming an immune sandwich complex comprising the monoepitopic antigen or an analog thereof, a first monoclonal antibody that binds to the monoepitopic antigen, and a second monoclonal antibody that is an antibody of the present invention and detecting the immune sandwich complex.

Abstract: The invention relates to methods of determining the presence or amount of an analyte in a sample suspected of containing the analyte, said method comprising the steps of: (a) bringing together in an aqueous medium to form a mixture: (i) the sample; (ii) at least one specific binder for the analyte; (iii) a first binding agent coupled to either (1) exogenous analyte or (2) the specific binder for the analyte; (iv) a support comprising a second binding agent; b) adding an activator to the mixture, wherein the activator binds the first binding agent and the second binding agent of the support to immobilize the first binding agent; c)determining the amount of the analyte in the sample by detecting the immobilized first binding agent, the presence or amount thereof being related to the presence or amount of the analyte in the sample.

Abstract: A sensor uses an immobilized affinity component capable of interacting with analyte species and being associated with a conducting polymer such that the interaction of the affinity component and the analyte induces change in the electrical properties of the polymer. An AC signal is applied to the polymer, and the induced change in impedance resulting from the interaction is measured. The impedance is measured at a frequency or frequencies corresponding to a peak or peaks in the relationship between frequency and impedance change for the polymer and the analyte. The measurement may be made by reference to the imaginary or real component of impedance. The polymer may be in the form of a layer bridging two electrodes between which the impedance is measured. The two electrodes may together define an interdigitated electrode assembly.

Abstract: An improved homogeneous enzyme immunoassay process for quantitatively analyzing an antigen by determining the change in the enzymatic activity caused by a reaction between the antigen and an enzyme-labeled antibody. The antigen is reacted with an enzyme-labeled antibody, followed by the reaction with a second antibody capable of recognizing and binding to a different epitope and then with a third antibody capable of recognizing and binding to the second antibody. The enzymatic activity of the labeling enzyme is determined by a water-insoluble substrate. Using the water-insoluble substrate, steric hindrance is enhanced. A highly-sensitive analysis can be carried out by a simple operation even when the antigen has a molecular weight falling within an intermediate range, for example, a range of M.W. 10,000 to 70,000.

Abstract: The present invention relates to a method of carrying out an immunoassay in a multiphase system. A sample containing an analyte is brought into contact with a receptor A and a tracer. The analyte can either form a complex with the tracer, or counteract the formation of a complex of receptor A and tracer by competing with the tracer for binding to receptor A, or counteract the formation of a complex of receptor A and tracer by competing with receptor A. Receptor B is added and the signal is determined. In this method, receptor A and receptor B are suitably immobilized, ensuring that the tracer either cannot enter into any binding involving the simultaneous participation of receptors A and B or can enter into such a binding to only such a slight extent that it is nevertheless possible to detect and differentiate differing analyte concentrations.

Abstract: A method of analyzing cells in a carrier solution comprises the following steps: (a) Introducing the carrier solution into a conduit having a surface portion (preferably a substantially flat surface portion). The carrier solution has the cells suspended therein. (b) Allowing the cells to settle on the surface portion, the surface portion including at least one imaging field. In an alternate embodiment, one or more discreet capture zones (e.g., formed from an affinity species immobilized on the substrate or a textured region on the substrate) are formed on the surface portion, and this step (b) comprises capturing the cells in the capture zone. (c) Sequentially interrogating a plurality of the cells in the imaging field with emitted light. (d) Processing resultant light from the imaging field. (e) Generating digital information for each of the plurality of cells from the resultant light. (f) Generating a response file for each of the plurality of cells from the digital information.

Abstract: Tartrate-resistant acid phosphatase (TRAP) has been used as a marker for bone resorption. However, there are two forms of said enzyme in the body: TRAP 5a and TRAP 5b, of which TRAP 5b is a much more specific marker. The present invention is directed to an immunoassay for measuring the bone resorption rate, which methods enables the specific determination of TRAP 5b, whereby the amount of TRAP 5b reflects the bone resorption rate. The method is useful in diagnosing disorders associated with a change in the bone resorption rate, such as osteoporosis. Methods of screening for susceptibility to such disorders, and method of monitoring the effect of treatment are also provided. Further a test-kit useful in said methods is provided.

Abstract: Heterogenous and homogenous assays are provided for the detection of protease inhibitory activity in a sample or target compound, taking advantage of the chemiluminescent characteristics of 1,2-dioxetanes. In the heterogenous assay, a peptide bearing a cleavage site for the protease of interest is provided with a first member of a first ligand binding pair at one end, and a first member of a second ligand binding pair at the other end. The other member of the first ligand binding pair is attached to a surface, which binds the peptide, or protease substrate, to the surface. The peptide substrate is combined with the protease and target compound or sample. Substrate cleavage, if not inhibited, is allowed to occur, and any unbound cleaved fragments are removed. An enzyme complexed with the second member of the second ligand binding pair is added, and allowed to bind to any of the (uncleaved) first member of the second ligand binding pair remaining.

Abstract: An enzyme-labeled immunoassay is performed by the steps of allowing a test sample to react with an enzyme-labeled reagent, allowing a substrate to react with the enzyme to form a signal, and immobilising the enzyme-labeled reagent, with the prevention of a further signal formation from a predetermined time on after the immobilisation of the enzyme-labeled reagent, using an enzyme inhibitor.

Abstract: The present invention has its objects to provide a compound not only which is easy to handle, thermally stable, and high in emission efficiency, but also which can show high emission efficiency without coexisting enhancer in the system even in a protic solvent. The present invention is related to a 1,2-dioxetane derivative of general formula (I). [wherein R1, R2, R3, R4 and R5 each independently represents hydrogen, alkyl or aryl; a pair of R2 and R3 and a pair of R4 and R5 may respectively be joined to each other to form a cycloalkyl group.

Abstract: In accordance with the present invention, a method of conducting an assay of a sample containing an analyte of interest includes the step of forming a mixture so as to bring a metal-ligand complex into interactive proximity with the sample containing the analyte of interest. The mixture is irradiated with electromagnetic light energy so as to cause emission of light indicative of the analyte of interest. The emitted light is measured, and the measurement of the emitted light is utilized to measure the analyte of interest. The metal-ligand complex can be [Re(bcp)(CO)3(4-COOHPy)]+, [Os(phen)2(aphen)]2+, [Os(tpy)(triphos)]2+, [Os(tppz)2]2+, and [Os(ttpy)2]2+, or the like. Also, the present invention is directed to a metal-ligand complex of the formula [Re(bcp)(CO)3(4-COOHPy)]+.

Abstract: The present invention concerns a method for the detection of an analyte in a sample liquid by luminescence measurement according to the principle of a ligand-receptor assay, e.g. an immunoassay or a hybridization assay or a combination thereof, wherein a sample liquid is incubated with at least one receptor which carries a luminescent label and the presence or/and the amount of the analyte to be detected is determined in the sample liquid by measuring the luminescence in a measuring medium containing dispersed components.

Abstract: The invention deals with the use of a reactive compound in immunological analyses. The compound is ouabain or its analog to which another compound, labeled by radioiodine or by a fluorogen, is coupled. The invention covers also the method to measure ouabain or its analog in plasma to diagnose cardiovascular and endocrine diseases and other harmful conditions.

Abstract: A new class of optical indicators which are capable of memorizing and preserving the spatial localization of intracellular analytes in a time resolved manner is described. The compounds comprise a chromophore carrying a photolabile group capable of undergoing an irreversible and detectable chemical transformation upon irradiation by light. The chromophore is linked to a binding site capable of binding an analyte, wherein binding of the analyte to the binding site alters an optical property of the chromophore, thus altering the ability of the photolabile group to undergo the chemical transformation. Methods and kits for memorizing the spatial localization of the analytes are also described.

Abstract: Compositions are disclosed comprising (a) a metal chelate wherein the metal is selected from the group consisting of europium, terbium, dysprosium, samarium osmium and ruthenium in at least a hexacoordinated state and (b) a compound having a double bond substituted with two aryl groups, an oxygen atom and an atom selected from the group consisting of oxygen, sulfur and nitrogen wherein one of the aryl groups is electron donating with respect to the other. Such composition is preferably incorporated in a latex particulate material. Methods and kits are also disclosed for determining an analyte in a medium suspected of containing the analyte. The methods and kits employ as one component a composition as described above.

Abstract: A method and compositions for the detection and/or quantification of an analyte through the use of a plurality of labeled probes, with two or more said probes targeted to different regions of said analyte. In specific embodiments, the labels are separately distinguishable, and/or are present at different specific activities on the labels.

Abstract: A method for fluorescence polarization immunoassay (FPIA) involves adding to a fluid container one or more reagents and a sample whose analyte is to be detected and measured, and then taking a first polarization measurement of the sample. More reagent is then added to the sample in the container, with no further sample addition to the container. A second or final polarization measurement of the sample is then taken, and the concentration of the analyte in the sample is then calculated based on the value of the two polarization measurements.

Abstract: A chemical moiety is disclosed which comprises a chemical, biochemical, or biological substance attached to one or more electrochemiluminescent organometallic compounds. In a preferred embodiment of the invention the substance is attached to one or more ruthenium-containing or osmium-containing luminescent organometallic compounds. Methods are disclosed for detecting low concentrations of the chemical moiety using chemiluminescent, electrochemiluminescent, and photoluminescent means. Compounds are disclosed which are useful for labeling substances of interest with ruthenium-containing and osmium-containing labels or other electrochemiluminescent labels. These labeled substances are useful in methods provided for detecting and quantifying analytes of interest in binding assays and competitive binding assays. The labeled substances are of particular use in homogeneous binding assays.

Abstract: An assay for the detection of antibodies to the MPB70 protein secreted by Mycobacterium bovis utilizes a tracer consisting of the MPB70 protein conjugated to a fluorophore such as fluorescein. Upon mixing with the antibodies specific for MPB70 protein contained in the serum of an animal infected with M. bovis, the bound tracer exhibits an increase in fluorescence polarization, detectable in an instrument.

Abstract: This invention provides methods for inhibiting fusion of HIV-1 to CD4.sup.+ cells which comprise contacting CD4.sup.+ cells with a non-chemokine agent capable of binding to a chemokine receptor in an amount and under conditions such that fusion of HIV-1 to the CD4.sup.+ cells is inhibited. This invention also provides methods for inhibiting HIV-1 infection of CD4.sup.+ cells which comprise contacting CD4.sup.+ cells with a non-chemokine agent capable of binding to a chemokine receptor in an amount and under conditions such that fusion of HIV-1 to the CD4.sup.+ cells is inhibited, thereby inhibiting the HIV-1 infection. This invention provides non-chemokine agents capable of binding to the chemokine receptor and inhibiting fusion of HIV-1 to CD4.sup.+ cells. This invention also provides pharmaceutical compositions comprising an amount of the non-chemokine agent capable of binding to the chemokine receptor and inhibiting fusion of HIV-1 to CD4.sup.+ cells effective to prevent fusion of HIV-1 to CD4.sup.

Abstract: Disclosed herein is a method for the detection of a target substance by a colloidal gold immunoassay, which comprises dissolving in an immunoreaction system a metal salt selected from the group consisting of sodium, potassium and lithium fluorides, sodium, potassium, lithium and magnesium iodides, sodium, potassium, lithium and magnesium bromides, lithium and magnesium chlorides, sodium, potassium, lithium and magnesium nitrates, sodium, potassium, lithium and magnesium sulfates, sodium, potassium, lithium and magnesium formates, sodium, potassium, lithium and magnesium acetates, and mixtures of at least two of these metal salts, whereby the metal salt is allowed to exist in a reaction mixture.

Abstract: In a fluorescence polarization assay for determining the amount of a target analyte in a test sample, wherein the amount of analyte is related to the amount of fluorescence emitted from the analyte-containing reagent medium, the improvement comprising contacting the analyte-containing reagent medium with of at least one compound from the group consisting of 1,10-phenanthroline, 8-hydroxy-7-iodo-5-quinoline, naphthalene-1-sulfonic acid, salts thereof, and any combination thereof.

Abstract: An in vivo method and apparatus for detecting an analyte in an individual. A sensor that includes a fluorescence reagent is placed in communication with the body fluids of the individual suspected of containing the analyte in such a way that once in place said sensor does not exit the skin of the individual. The sensor is configured to retain the fluorescence reagent while allowing analyte to diffuse into and out of said sensor. The sensor is illuminated transdermally, and the fluorescence from the fluorescence reagent associated with the presence of the analyte is measured.

Abstract: A non-competitive method for the determination of analytes. Initially the analyte is bound to a specific binding partner, after which the unoccupied binding sites of the binding partner are inactivated. The bound analyte is then dissociated from the binding partner and replaced by a labeled marker, after which the bound labeled marker is determined. The signal from the bound labeled marker is directly proportional to the initial amount of analyte in the sample, which makes the present method more favorable than the competitive assays.

Abstract: Avidin-binding azo reagents which alter the spectrophotometric properties of avidin and the use of such reagents in homogeneous assays are described.

Abstract: A method for the spectroscopic determination of a marker comprises:(a) contacting chelated lanthanide metal ions bound to a marker with a buffered solution comprising a detergent, an enhancer reagent and a polyanion, wherein the buffer maintains the pH of the solution within the range of about 3.5 to about 11.5 and the polyanion is present in sufficient concentration such that the lanthanide metal ion disassociates from the chelate complex and reassociates with the enhancer reagent, thereby transferring the lanthanide metal ion into fluorescent form; and(b) determining the amount of lanthanide metal ion liberated from the marker as a measure of the amount of marker present by subjecting the solution to a short radiation pulse and detecting the fluorescence of the lanthanide metal ion after the fluorescence from any background sources substantially has ceased.

Abstract: The present invention relates to a method of carrying out an immunoassay in a multiphase system. Particularly, a sample containing an analyte is brought into contact with a receptor A and a tracer. The analyte can either from a complex with the tracer, or counteract the formation of a complex of receptor A and tracer by competing with the tracer for binding to receptor A, or counteract the formation of a complex of receptor A and tracer by competing with receptor A. Receptor B is added and the signal is determined. In this method, receptor A and receptor B are suitably immobilized, ensuring that the tracer either cannot enter into any binding involving the simultaneous participation of receptors A and B or can enter into such a binding to only such a slight extent that it is nevertheless possible to detect and differentiate differing analyte concentrations.

Abstract: The present invention concerns new metal complexes with a charged linker and their use as luminescent marker groups in an immunoassay.

Abstract: The present invention provides a topiramate immunoassay and reagents for use in the immunoassay. In particular, topiramate is derivatized at the sulfamate moiety or the 9-carbon or 10-carbon methyl group of topiramate to add a label bound directly or through a linking group for use as a tracer (competitive analyte analog) or to add a linking group bound to a carrier for use as an immunogen to induce anti-topiramate antibodies. Immunoassay methods and kits are also provided.