Abstract: Methods are provided for the use of magnetically responsive particles in systems in which the separation of certain molecules, macromolecules and cells from the surrounding medium is desirable. The magnetically responsive particles may be coupled to a wide variety of molecules. The magnetic particles can be dispersed in aqueous media without rapid settling and conveniently reclaimed from media with a magnetic field. Preferred particles do not become magnetic after application of a magnetic field and can be redispersed and reused.

Abstract: A composition for determining the fibrinogen content in plasma by electroimmunodiffusion, said composition essentially comprising heparin and agarose.

Abstract: A novel polypeptide, Alzheimer's Amyloid Polypeptide (AAP), is provided in substantially purified form which is isolated from amyloid deposits in patients with Alzheimer's Disease. The polypeptide has the following amino acid sequence: ##STR1## The polypeptide, or fragments thereof, may be used to produce antibodies useful in a diagnostic test for Alzheimer's Disease. Nucleotide probes corresponding to portions of the polypeptide are also useful for diagnostic purposes.

Abstract: Assay for a hapten or antigen wherein supported hapten or antigen is used to separate "bound" and "free" fractions. The sensitivity of the assay is increased.

Abstract: A method to produce actively growing mycoplasma organisms in microcolonies and which have a high content of species specific membrane antigen, is disclosed. The specific membrane antigen can be used to detect specific antibodies against mycoplasma in a patient's serum samples. It can also be used to elicit antibody production in animals so that the specific membrane antigen of mycoplasma can be detected using animal antibody tracers, in the sputum of patients having a mycoplasma infection.

Abstract: A method for measuring plasma levels of an inhibitor of (Na.sup.+ +K.sup.+)ATPase associated with hypertension comprising:(1) incubating deproteinized plasma of a patient suspected of being hypertensive in a (Na.sup.+ +K.sup.+)ATPase assay solution comprising (a) (Na.sup.+ +K.sup.+)ATPase; and(2) following the activity of the (Na.sup.+ +K.sup.+)ATPase over the course of time, and use of the method in diagnosing hypertension and in monitoring anti-hypertensive therapy.

Abstract: A method of specimen treatment preparatory to conducting an immunoassay is disclosed whereby a microbial protein is solubilized by a detergent at elevated temperatures and in the presence of an alkali or alkaline earth metal ion. At elevated temperatures, the detergent is soluble. However, at lower temperatures, the presence of the metal ion renders the detergent insoluble so that it is prevented from interacting in the immunoassay procedure. A specific application is in the solubilization of the principal outer membrane protein of Chlamydia trachomatis.

Abstract: Bifunctional coupling agent for joining radionuclide metal ions to biologically useful molecules, including antibody Fab' fragments are disclosed. The coupling agents contain a maleimide moiety and a paramagnetic or radionuclide chelating moiety. The maleimide can be used to selectively bind to free sulfhydryl groups, or amine groups.

Abstract: An improved imaging technique involving nuclear magnetic resonance. Known drug or neurotransmitter receptor ligands are covalently bound to magnetic resonance image enhancing spin label compounds, such as sterically hindered free radical nitroxide compounds, with the resulting adduct being administered to a patient, and thereafter when the ligand is bound to specific receptor sites in the soft tissue such as the brain, regional tissue area is assessed with nuclear magnetic resonance, allowing diagnostic discrimination.

Abstract: A lysing agent and a method for utilizing the lysing agent in the identification and enumeration of cells of a select subclass of leucocytes is provided. The lysing agent includes formaldehyde, an alkali or alkaline earth salt of a weak acid and a polyhydric alcohol.

Abstract: Immunogens for preparing antibodies against the drug lidocaine and related compounds, labeled conjugates, synthetic intermediates, and the use of such antibodies and labeled conjugates in immunoassays for determining lidocaine and such related compounds. The immunogens comprise lidocaine or an analog thereof coupled through one of the aromatic methyl groups to a conventional immunogenic carrier. The antibodies and labeled conjugates are particularly useful in homogeneous nonradioisotopic immunoassays for measuring lidocaine or its analogs in biological fluids such as serum.

Abstract: Apparatus and method for providing an optical detection of a binding reaction between a ligand and an antiligand, including, a pattern formed by a spatial array of microscopic dimensions of antiligand material, ligand material interacting with the antiligand material to produce a binding reaction between the ligand and the antiligand in the pattern, a source of optical radiation including energy at at least one wavelength directed to the pattern at a particular incidence angle to produce scattering of the energy from the pattern in accordance with the binding reaction and with a strong scattering intensity at one or more Bragg scattering angles, and at least one optical detector located relative to the pattern and aligned with a Bragg scattering angle to detect the strong scattering intensity at the Bragg scattering angle to produce a signal representative of the binding reaction.

Abstract: The metabolism and growth of cells is measured by suspending the cells in a liquid medium capable of forming a gel. The resultant suspension is formed into small droplets which droplets are caused to gel. Samples of the gel microdroplets (GMDs) are treated to alter the metabolism or growth of the cells, and the amount of metabolites, or other cellular products or external reaction products within each GMD is measured. The process can be utilized to determine essentially simultaneously the enumeration or count and the antibiotic susceptibility, or susceptibility to other compounds, factors, biological agents or other cells, of the cells which are representative of a larger sample of said cells.

Abstract: Chelates of gadolinium with 1,4,7-triazacyclononane-N,N',N"-triacetate; 1,4,7,10-tetrazacyclododecane-N,N',N'"tetraacetate; and 1,5,9-triazacyclododecane-N,N',N"-triacetate are useful as NMR contrast agents.

Abstract: Water soluble, substantially nontoxic salts of compounds of the formula:CF.sub.3 Rwherein R is --SO.sub.3 H, --SO.sub.2 NH.sub.2 or --PO.sub.3 H.sub.2, are useful for obtaining fluorine magnetic resonance images of body organs and tissues. Illustrative salts of such compounds include sodium trifluoromethane sulfonate, N-methylglucaminium trifluoromethanesulfonate and N-methylglucaminium trifluoromethanesulfonamide.

Abstract: A method of determining dTk isoenzyme levels of a human or animal body fluid or cell sample is disclosed, which comprises the steps of reacting said sample with a substrate for said isoenzyme in the presence of a phosphate donor and a buffer system, and measuring the amount of phosphorylated product formed, said amount being proportional to said isoenzyme level. The method is characterized by using in combination(a) a buffer system at pH ranging from 5 to 9 and being present in a concentration of no more than 250 mM,(b) a substrate consisting of 2'-deoxy-5-halouridin, part of which has a radio-labelled 5-halogen, and being present in a concentration ranging from 2.times.10.sup.-9 -5.times.10.sup.-6 M, and(c) the phosphate donor being present in a concentration not exceeding 20 mM.The sensitivity of the method permits measurement of minute amounts of dTk, and the method can be used for e.g.

Abstract: The Ferrioxamine (FOM) family of chelates and amide homologs thereof provide excellent contrast agents for magnetic resonance (MR) imaging. The magnetic dipole generated by unpaired electrons within the paramagnetic Fe(III) atoms, cause a local reduction in the bulk magnetic field Bz of the MR system. The resulting shorting of the T1 (spin lattice) relaxation time in the local hydrogen protons within the area of interest, causes an intense "free induction signal" and a corresponding modulation in the collected scanning data. The contrast agent within the tissue or organ of interest causes the tissue to appear on the MR display as a high intensity or white area. Background tissue is displayed as darker or lower intensity greys.FOM does not penetrate the blood-brain-barrier under normal circumstances; and is therefore useful in detecting the extravasation of arterial blood in the extravascular space during cerebral hemorrhaging and in the endema fluid surrounding tumors.

Abstract: Disclosed is a process and device for facilitating the differentiation of particles in a medium. The particles are exposed to a rotating electrical field of variable rotational frequency. By providing a means for adjusting the frequency of the rotating fields, the particles can be caused to rotate in different directions thereby facilitating differentiation of particles belonging to different groups of particles. An apparatus for implementing this process includes at least three electrodes which are arranged so as to form a space therebetween. A device for producing a rotating field of variable rotational frequency is connected to the electrodes.

Abstract: An emulsion (in which an aqueous medium contains small liquid droplets coated with a protein that will interact specifically with a select protein) is mixed with a liquid sample, time is allowed for interaction to occur and the mixture is then exposed to a tagged antibody specific to the select protein. After an appropriate hold time the emulsion is broken and the protein that previously covered the disperse droplets becomes concentrated at the surface. The surface is checked for the presence of the tagged antibodies to establish the presence of absence of the select protein.

Abstract: An immunoassay method for measuring a concentration of an antigen for a short period of time by immobilizing an antibody over the whole zone of an effective supporting matrix for electrophoresis and fixing an antigen in a sample to be measured by electrophoresis for the antigen-antibody reaction between said immobilized antibody and said antigen.