Abstract: A direct particle agglutination immunoassay for assaying an antigenic substance (Ag) in a fluid. The immunoassay is the type which comprises:(a) contacting the fluid with an antibody (Ab) coated particle (P) to agglutinate the Ab coated particles; and(b) detecting the presence of agglutination.The immunoassay is characterized in that the fluid is contacted with at least one additional entity selected from a group consisting of at least one different type of antibody (Ab.sub.a) coated particle (P.sub.1) and at least one different type of antibody (Ab.sub.b). The P.sub.1 is selected from a group consisting of P, at least one different particle (P.sub.2), and mixtures thereof (P and P.sub.2). Each type of Ab.sub.a -P.sub.1 and Ab.sub.b has a lower average affinity constant (K) for Ag than the K of Ab-P and the additional entity is present in an amount sufficient to avoid a high antigen false negative effect.Also, a reagent of the type comprising Ab-P.

Abstract: A substrate solution comprising (a) a substrate selected from a group consisting of salts of L-.gamma.-glutamyl-p-nitroanilide and L-.gamma.-glutamyl-3-carboxy-p-nitroanilide; and (b) a polyol selected from a group consisting of alkyl polyols containing 2 to 10 carbon atoms and 2 to 10 hydroxy groups and polyethylene glycol having an average molecular weight of from about 200 to about 600.Also, a kit for the determination of .gamma.-glutamyltransferase activity of the type comprising (a) a buffered medium comprising a buffer and a .gamma.-glutamyl residue acceptor; and (b) a substrate solution; the buffered medium and substrate solution being adapted such that preselected aliquots thereof can react in the presence of .gamma.-glutamyltransferase to produce an absorbing cleavage product. The kit is characterized in that the substrate solution is as described above.In addition, a method for determining .gamma.

Abstract: A method, kit and a solution for assaying enzyme, such as prostate acid phosphatase (PAP), in a sample. The sample is contacted with a first antibody (Ab.sub.1) against the enzyme and incubated. The resulting Ab.sub.1 -enzyme complex is contacted with a second antibody (Ab.sub.2) specific for Ab.sub.1. The resulting Ab.sub.2 -Ab.sub.1 -enzyme complex precipitates out of the medium. The precipitated complex is separated and solubilized with a pH controlled solution of gamma globulin. The resulting solution is then assayed for enzyme activity.

Abstract: A device for handling and washing beads. The device is attachable to a test tube rack and includes a frame, a containing slide, and a capture slide. By manipulating the slides in various combinations of positions the beads may be added to, removed from, or separately washed apart from test tubes in the rack. Complete and easy washing of the beads may thus be accomplished.

Abstract: A wavelength calibration solution comprising from about 0.025 to about 0.140 molar neodymium and from about 0.135 to about 0.550 molar samarium, wherein the neodymium is present as a neodymium ionized constituent and the samarium is present as a samarium ionized constituent.A method for checking the wavelength accuracy of spectrometers or spectrophotometers of the type comprising measuring the absorbance (A) or percent transmittance (% T) of a wavelength calibration check solution versus a blank at more than one wavelength. The method is characterized in that the above solution is employed therein as the wavelength calibration check solution.

Abstract: A solution of the type comprising cobalt ammonium sulfate and sulfuric acid. The solution is characterized in that it comprises from about 0.020 to about 0.040 N H.sub.2 SO.sub.4.Also, a method for checking the linearity of response of a spectrometer or spectrophotometer. The method is of the type comprising measuring absorbance (A) or percent transmittance (%T) of a solution versus a blank at a known wavelength. The method is characterized in that the above solution is employed therein.In addition, a method for checking photometric accuracy of a spectrometer or spectrophotometer. The method is of the type comprising measuring A or %T of a solution at a specific wavelength. The method is characterized in that the above solution is employed therein.

Abstract: A method for checking noise of a spectrometer or spectrophotometer. The method is of the type comprising measuring absorbance (A) or percent transmittance (%T) of a solution over a period of time. The method is characterized in that the solution comprises from about 0.040 to about 0.090 M nitrite, the nitrite being present as a nitrite ionized constituent.

Abstract: Novel peptides having the following amino acid sequence ##STR1## wherein X.sub.1, X.sub.2, and X.sub.3 are selected from a group consisting of N-terminal and desamino alpha-carbon substitutions and a and b are 0 or 1, provided that a and b are always 0 when A.sub.1 is a desamino residue; A.sub.1 and A.sub.4 are selected from a group consisting of histidyl, arginyl, lysyl, .alpha.-naphthylalanyl, .beta.-naphthylalanyl, isoquinolyl, tyrosyl, tryptophyl, phenylalanyl, homologues and analogues thereof, and, with respect to A.sub.1 only the desamino forms thereof; A.sub.2 and A.sub.5 are selected from a group consisting of D-histidyl, D-arginyl, D-lysyl, D-.alpha.-naphthylalanyl, D-.beta.-naphthylalanyl, D-isoquinolyl, D-tyrosyl, D-tryptophyl, D-phenylalanyl, homologues and analogues thereof; A.sub.

Abstract: A stable blood serum bilirubin reference composition characterized in that the composition possess a pH of from about 8.2 to about 9.2 and comprises (a) a sulfhydryl compound in an amount sufficient to enhance the stability of the bilirubin and (b) a chelating agent in an amount sufficient to bind all the metals present in the blood serum moiety of the composition. This blood serum bilirubin composition when stored in a gas impervious vial under an inert atmosphere has an excellent shelf life.

Abstract: Powder compositions useful for making conductors, e.g. microcircuit conductors, end terminations for capacitors, electrodes for gas discharge display devices, etc. The compositions comprise inorganic powders dispersed in an inert vehicle and are printed and fired in the conventional manner on dielectric substrates. The inorganic powders comprise aluminum, silicon, and glass.

Abstract: Nematic liquid crystal compositions containing 4'-substituted-4-cyanobiphenyl and 4, 4'-disubstituted phenyl benzoate liquid crystal compositions which can be actuated at low voltages, e.g., under 3.5 Vrms in a 12.5 micron thick twisted nematic liquid crystal display.

Abstract: The range of linearity of the kinetic method for the determination of glucose concentrations using a reagent of the type comprising a buffer, a pyridine coenzyme, and glucose dehydrogenase, is significantly increased when the buffer employed in the reagent has a pH of from about 7.9 to about 9.0.

Abstract: A novel enzymatic reagent and method is provided for increasing the sensitivity of enzymatic substrate analyses using oxygen rate analyzers. The reagent is a buffered solution containing an enzyme which reacts specifically with oxygen and with the substrate being measured. The reagent also contains a salt or a combination of salts in quantities sufficient to reduce the solubility of oxygen in the reagent by at least thirty percent when compared to the solubility of oxygen in water. Upon being mixed with a specimen containing the specific enzyme substrate being measured, the enzyme catalyzes the reaction of the substrate and the oxygen. The rate of reaction of oxygen is measured, and the amount of total substrate is determined by means which translate the rate of oxygen consumption into the concentration of total substrate present in the specimen.

Abstract: A reagent system for beta-amylase assay comprising:A polysaccharide having glucose molecules primarily connected through alpha 1,4 linkagesPhosphate ionsMaltose phosphorylaseA co-enzyme selected from a group consisting of beta-nicotinamide-adenine dinucleotide, beta-nicotinamide-adenine dinucleotide phosphate, and mixture thereofGlucose-6-phosphate dehydrogenaseBeta-D-phosphoglucomutaseMutarotase.

Abstract: A kinetic assay is provided for measuring alpha-amylase content in aqueous solutions. The assay is based on the following reactions:alpha-1,4 linked glucan .sup.alpha-amylase alpha-maltosealpha-maltose + PO.sub.4 .sup.-.sup.-.sup.- .sup.MP Glucose + beta-D-G-1-Pbeta-D-G-1-P .sup.beta-PGM G-6-PG-6-P + NAD .sup.G6PDH 6-P-G + NADHthe concentration of alpha-amylase is determined by measuring the rate of increase in absorbance associated with the production of NADH which is a measure of the activity of alpha-amylase.A novel reagent system is used with the assay and comprises:A polysaccharide having glucose molecules primarily connected through alpha 1,4 linkageMaltose phosphorylase (MP)Phosphate ions (PO.sub.4 .sup.-.sup.-.sup.

Abstract: An arrangement for the controlled delivery of liquid reagent is shown wherein a reservoir vessel for storing the liquid in volume is coupled to replenish a "vestibule vessel" provided for intermediate storage of the liquid enroute to the delivery point and for pneumatic propulsion thereof, the liquid being pneumatically driven from reservoir to the vestibule through a unidirectional check valve.