Abstract: The present invention concerns a method of enzymatically determining the pH of a specimen (e.g., a solution or a biological fluid) and a kit for conducting the method. The present method involves mixing (1) a specimen with (2) an enzyme and (3) one or more substrates for the enzyme in a buffered solution having a pH effective to provide a direct proportional relationship between the activity of the enzyme and the pH of the specimen; determining the activity of the enzyme; and correlating the activity of the enzyme to the pH of the specimen. Each of the sample, the enzyme, the substrate and the buffered solution is present in an amount effective to provide the direct proportional relationship between the activity of the enzyme and the pH of the specimen.

Abstract: A solution for the preservation or perfusion of organs contains sodium lactobionate, sodium dihydrogenphosphate, raffinose, glutathione, allopurinol, nafamostat mesilate (mesylate) and optionally cyclodextrin, preferably 100-120 mM, 2-25 mM, 25-35 mM, 2-4 mM, 1-2 mM and 0.5-1 mM, respectively. The solution may be used for perfusion and storage of organs. Also disclosed are methods of use of the solution to perfuse and store organs.

Abstract: The method is directed to assaying for biological components in a sample comprising step (A) generating an oxidase substrate in the presence of an amphoteric surfactant and in the absence of ferrocyanide; (B) initially generating hydrogen peroxide through said oxidase reaction on said substrate of oxidase with subsequent detection of the generated hydrogen peroxide using peroxidase and a color developer capable of being oxidized in the presence of amphoteric surfactant and ferrocyanide; and (C) correlating the amount of color developed to the amount of biological components in the biological sample. Even when the biological component to be detected is present in a very small amount, the interference of bilirubin can be eliminated in assays of biological components in which peroxidase generated from an enzymatic reaction is detected using peroxidase and a color developer capable of being oxidized.

Abstract: A method for assaying an enzyme on a targeted solid body surface, including the steps of contacting an end opening of a thin tube with a targeted solid body surface to form a space between the targeted solid body surface and inner wall surface of the thin tube, supplying a substrate solution into the space to bring the substrate solution in contact with the targeted solid body surface, and determining a pH change of the substrate solution in the space by using a pH electrode; and an apparatus therefor.

Abstract: There is provided cardioplegic solutions for arresting an organ intended for transplantation and preservation solutions for perfusing and storing an organ while awaiting transplantation. The cardioplegic solutions include, per liter of solution, a balanced isotonic solution of sodium, potassium, calcium, and magnesium ions and bicarbonate in a physiologically acceptable amount, from about 0.5 .mu.M to about 2.0 .mu.M of an amiloride-containing compound; and water sufficient to make a liter of solution. The amiloride-containing compound may be amiloride, hexamethylene amiloride, dimethyl amiloride, ethyl isopropyl amiloride or methyl isobutyl amiloride. The preserving solutions are based on the isotonic solutions described and include other components such as EDTA, a small amount of adenosine, and at least one antioxidant. There is also provided a method for arresting an organ, storing an organ and transplanting an organ all at room temperature for up to at least 24 hours.

Abstract: An aqueous solution for organ preservation or maintenance, which contains: a vasodilator in an amount sufficient to maintain vascular homeostasis; D-glucose in an amount sufficient to support intracellular function and maintenance of cellular bioenergetics; magnesium ions in an amount sufficient to support intracellular function and maintenance of cellular bioenergetics; macromolecules of molecular weight greater than 20,000 daltons in an amount sufficient to maintain endothelial integrity and cellular viability; potassium ions in a concentration greater than about 110 mM; and a buffer in an amount sufficient to maintain the average pH of the organ preservation or maintenance solution during the period of organ preservation at about physiologic pH or above.

Abstract: Enzymatically clearable chemiluminescent 1,2-dioxetane compounds capable of producing light energy when decomposed, substantially stable at room temperature before a bond by which an enzymatically clearable labile substituent thereof is intentionally cleaved, are disclosed. These compounds can be represented by the formula: ##STR1## wherein: X and X.sup.1 each represent, individually, hydrogen, a hydroxyl group, a halo substituent, an unsubstituted lower alkyl group, a hydroxy (lower) alkyl group, a halo (lower) alkyl group, a phenyl group, a halophenyl group, an alkoxyphenyl group, a hydroxyalkoxy group, a cyano group or an amide group, with at least one of X and X.sup.1 being other than hydrogen; and R.sub.1 and R.sub.2, individually or together, represent an organic substituent that does not interfere with the production of light when the dioxetane compound is enzymatically cleaved and that satisfies the valence of the dioxetane compound's 4-carbon atom, with the provisos that if R.sub.1 and R.sub.

Abstract: A colorimetric enzymic analytical test element comprises a support and a plurality of reaction zones incorporating a dried enzyme composition, dyestuff and reagent adapted to provide a substantial dosage independent colorimetric display when the concentration of an analyte applied to the elements exceeds a predetermined value.

Abstract: The present invention relates to a three-dimensional cell culture system which can be used to culture a variety of different cells and tissues in vitro for prolonged periods of time. In accordance with the invention, cells derived from a desired tissue are inoculated and grown on a pre-established stromal support matrix. The stromal support matrix comprises stromal cells, such as fibroblasts actively growing on a three-dimensional matrix. Stromal cells may also include other cells found in loose connective tissue such as endothelial cells, macrophages/monocytes, adipocytes, pericytes, reticular cells found in bone marrow stroma, etc. The stromal matrix provides the support, growth factors, and regulatory factors necessary to sustain long-term active proliferation of cells in culture. When grown in this three-dimensional system, the proliferating cells mature and segregate properly to form components of adult tissues analogous to counterparts found in vivo.

Abstract: The present invention relates to a three-dimensional cell culture system which can be used to culture a variety of different cells and tissues in vitro for prolonged periods of time. In accordance with the invention, cells derived from a desired tissue are inoculated and grown on a pre-established stromal support matrix. The stromal support matrix comprises stromal cells, such as fibroblasts actively growing on a three-dimensional matrix. Stromal cells may also include other cells found in loose connective tissue such as endothelial cells, macrophages/monocytes, adipocytes, pericytes, reticular cells found in bone marrow stroma, etc. The stromal matrix provides the support, growth factors, and regulatory factors necessary to sustain long-term active proliferation of cells in culture. When grown in this three-dimensional system, the proliferating cells mature and segregate properly to form components of adult tissues analogous to counterparts found in vivo.

Abstract: A solution suitable as a hypothermic blood substitute for replacing blood in euthermic subjects during surgery are provided. The blood substitute contains a purge solution and a maintenance solution, the latter of which is useful for organ preservation. The purge solution contains an aqueous solution of electrolytes at physiological concentrations, a macromolecular oncotic agent, a biological pH buffer effective under physiological and hypothermic conditions, a simple sugar, and a substrate for the regeneration of ATP. The maintenance solution contains a second aqueous solution of electrolytes containing potassium ions at a concentration range of from 35 to 45 mM, sodium ions at a concentration range of from 80 to 120 mM, magnesium ions at a concentration range of from 2 to 10 mM, chloride ions at a concentration range of from 15 to 20 mM, and calcium ions at a concentration range of from 0.01 to 0.

Abstract: A method for preserving mammalian hearts while under ischemic conditions is accomplished by exposing the heart to a preservation solution containing a pharmacologically effective concentration of a Na.sup.+ /K.sup.+ /Cl.sup.- co-transporter blocker agent, such as Furosemide, Bumetanide or Piretanide, thereby extending survival of the heart.

Abstract: A computer-controlled apparatus and method for perfusing a biological organ, such as a heart, kidney, liver, etc. The apparatus comprises a plurality of fluid reservoirs and an organ container for holding the biological organ. A first fluid flow path is defined as a loop from the plurality of reservoirs to necessary sensors and temperature conditioning means and back to the plurality of reservoirs. The reservoirs are selectively connectable to the first fluid flow path. Pump means are interposed in the first fluid flow path for pumping fluid from the first fluid flow path to a second fluid flow path. The organ container is located in this second fluid flow path. Pump means may also be included in the second fluid flow path for pumping fluid from the organ container to one or more of the reservoirs or to waste. One or more sensors are interposed in the fluid flow paths for sensing at least one of the concentration, temperature, pH, and pressure of the fluid flowing in the first and second fluid flow paths.

Abstract: A dye couple, comprising 3-methyl-2-benzothiazolinone hydrazone (MBTH) and 8-anilino-l-naphthalenesulfonate (ANS), is used as an indicator in a reaction cascade producing a strong oxidizing agent, such as hydrogen peroxide or other peroxides or perborates. The strong oxidizing agent reacts with the dye couple to produce a blue dye stuff. The MBTH-ANS dye couple exhibits strong and flat spectral absorption at the region of about 600 to 650 nm. This region is free of blood color interference, which enables one to measure glucose and other analytes that react with an oxidase enzyme to produce the strong oxidizing agent, through the use of LED optics, accurately without much optic calibration. Further, the MBTH and ANS are very soluble in aqueous solution, yet become insoluble upon oxidative coupling. The poor solubility minimizes dye fading, thus providing a stable endpoint.

Abstract: An improved test composition for the diagnosis of gastric disease by detecting the presence of urease associated with H. pylori in a biopsy specimen is described in which the hydrolysis of urea by urease is detected by a combination of at least two dye indicators showing a color change and a positive result at an acid pH, in which the positive color is distinctive from the color of the biopsy specimen, and in which most positive results occur in 2-10 minutes and all occur in no more than 4 hours. Specific compositions are disclosed.

Abstract: A reusable, miniature, implantable electrochemical sensor, a method of making the same, and a powder therefor are provided. Enzyme material is immobilized on bulk particulate matter, and a reaction chamber of the sensor is then filled therewith. The sensor is implanted in an environment where it comes into contact with a specific component of a fluid with which the enzyme material chemically reacts to produce electrical signals for measuring the reaction.

Abstract: A rapid method and easy to use unitized test device is disclosed for determining the presence of Helicobacter pylori in a biological tissue specimen by detecting the presence of urease in the tissue. The system basically utilizes a multilayer test device for separating and optimizing the various reactions involved, i.e. the urease in the specimen with a substrate and the ammonia generated thereby with an indicator element.

Abstract: A biosensor is prepared having a selective detection system containing a biochemical substance such as an enzyme immobilized on an olefinic-unsaturated, epoxyfunctional polysiloxane. Prior to immobilization of the biochemical substance, the polysiloxane is applied as a layer to a carrier and cross-linked by treatment with high-energy radiation. A biochemical substance is reacted with epoxy groups of the cross-linked polysiloxane. Any non-reacted epoxy groups are reacted with a compound containing an amino group, a carboxyl group or an amino group and a carboxyl group to stabilize. After cross-linking and before reacting of the biochemical substance, the cross-linked polysiloxane can be hydrophilized by reacting some of the epoxy groups with a hydrophilic compound containing a reactive group.

Abstract: A method for detecting urea in a liquid sample in which urease is adsorbed on a solid support such as a membrane and contacted with a solution suspected of containing urea, a pH-dependent reducing agent and a tetrazolium salt. When urea is present in the solution, the adsorbed urease converts it to ammonia, thus raising the pH and causing the pH-dependent reducing agent to reduce the tetrazolium salt to an insoluble colored formazan. The formazan precipitates as a detectable spot on the solid support, indicating the presence of urea in the liquid sample.

Abstract: There is disclosed a composition for measurement of potassium ion concentration, which contains a) pyruvate kinase, b) glycerol kinase, c) glycerol-3-phosphate oxidase, d) peroxidase, e) a chromogen of reduced type, f) adenosine diphosphate or a salt thereof, and g) phosphoenolpyruvic acid or a salt thereof. Also disclosed is a composition for elimination of ammonium ions, which contains a) glutamate dehydrogenase, b) glucose dehydrogenase, and c) nicotinamide adenine dinucleotide of reduced type (NADH) or nicotinamide adenine dinucleotide phosphate of reduced type (NADPH).

Abstract: A substrate composition for use in a solid phase enzyme assay for urease or in a solid phase enzyme immunoassay which includes urease as a label. The substrate composition includes a compound converted by urease to ammonia and a pH dependent reducing agent which reduces a tetrazolium salt when the pH of the medium has been raised by the ammonia produced. The tetrazolium salt may optionally be included in the substrate composition. Reduction of the tetrazolium salt produces a colored insoluble formazan which precipitates on the solid phase as an indication of the presence of urease.

Abstract: A rapid method and easy to use unitized test device is disclosed for determining the presence of Helicobacter pylori in a biological tissue specimen by detecting the presence of urease in the tissue. The system basically utilizes a multilayer test device for separating and optimizing the various reactions involved, i.e. the urease in the specimen with a substrate and the ammonia generated thereby with an indicator element.

Abstract: An integral multilayer analytical element for the determination of ammonia or an ammonia-producing substance comprising a light-transmissive liquid-impermeable support, an indicator layer containing an indicator which produces a detectable change by gaseous ammonia, a liquid permeation barrier layer, a reagent layer containing an alkaline buffer and optionally a reagent capable of reacting with a substance to produce ammonia and a spreading layer laminated in this order, which is improved by that the indicator layer contains a polyvinyl alkyl ether, and/or which is improved by that the surface of said support facing toward the indicator layer is undercoated with a polyvinyl alkyl ether, a hydroxyalkyl cellulose, an alkyl cellulose, polystyrene, a polyalkyl methacrylate, polyviriylidene chloride, polyvinyl alcohol or polyvinyl pyrrolidone, substantially not containing ammonia and ammonium ion.

Abstract: A test kit for determining the relative level of nitrogen of a user who is involved in a health program where diet and exercise are monitored and adjusted for optimizing physical development, the system includes a plastic stick having a first reagent zone on which is included a reactant such as urease, and a pH indicator such as bromthymol blue, and a second reagent zone on which is included a reactant indicator such as sodium nitroprusside used in conjunction with color chart blocks representing a range of urea nitrogen and ketone concentrations, wherein the user's urine nitrogen and ketone content can be determined by comparing the altered color of the reagent zone of an exposed test strip to the color chart blocks and compared with a personal baseline level, developed from a number of tests under controlled conditions, for determining the present protein nitrogen turnover and approximate balance, and the body fat metabolism.

Abstract: Urea, creatinine, creatine, triglycerides, or the like in a specimen can be accurately determined by terminating an isocitrate dehydrogenase reaction by addition of a chelating agent in a system wherein NADP.sup.+ formed from NADPH is reproduced into NADPH in the conjoint presence of an isocitrate, metallic ions such as magnesium or manganese ions, and isocitrate dehydrogenase in assaying a substance by means of a reaction of NADPH to NADP.sup.+.

Abstract: A method for determination of an analyte in a sample containing reducing substances is disclosed. After the decomposition of the reducing substances by reaction with hydrogen peroxide formed by enzymatic Redox reaction using a component in the sample which does not participate in another enzymatic Redox reaction using the analyte, the remaining hydrogen peroxide is decomposed, and then the analyte is subjected to enzymatic Redox reaction to form hydrogen peroxide which is then determined by a known method.

Abstract: A method and apparatus for automatically and rapidly, retrieving, counting and/or analyzing at least one selected population of cells or formed bodies, such as a white blood cell population and at least one subset thereof of a whole blood sample or portion thereof. A volume of a biological medium containing the white blood cells is prepared and at least one reactant specific or preferential at least to some selected biological cells is introduced thereto and rapidly mixed for a short period of time. The opacity and/or volume parameter of the cells can be modified and the mixture is then counted and analyzed in one or more steps to obtain the desired white blood cell population and subset analysis. The biological sample can be a whole blood sample and the reactant can include or be a lyse or a monoclonal antibody bound to microspheres, which will bind to specific ones of the cells or a combination of lyse and microspheres with antibody bound thereto.

Abstract: A rapid, competitive enzyme linked immunosorbent assay (cELISA) for the determination of Bluetongue virus antibodies in serum is described. This method utilizes either a biotinylated monoclonal antibody to Bluetongue virus and streptavadin-enzyme in conjunction with synthetic substrate, or an enzyme-conjugated monoclonal to detect antibodies specific for Bluetongue virus.

Abstract: A system for analyzing a biological fluid or the like for a constituent of interest comprises structure defining a sample inlet port, structure defining an analysis region, a measuring system connected in sensing relation to the analysis region, and structure defining a reaction chamber that has an immobilized enzyme capable of modifying the constituent of interest. Control means operates liquid flow means in a unidirectional sample flow mode to initially flow a sample of material to be analyzed from the sample inlet port to the reaction chamber and to the analysis region for a measurement of unmodified sample material, and then operates the liquid flow means in a bidirectional sample flow mode to oscillate the sample material in the reaction chamber and facilitate modification by the immobilized enzyme of the constituent of material in the sample.

Abstract: A method for enzyme immunoassay of a ligand includes urease as a label. A bound fraction of ligand and antiligand conjugated to urease is formed on a solid support. The urease component of the bound fraction is contacted with a substrate composition for urease which includes a compound converted to ammonia by the urease, a tetrazolium salt and a pH dependent reducing agent which reduces the tetrazolium salt when the pH of the assay medium has been raised by the ammonia. The tetrazolium salt is reduced to a colored insoluble formazan which precipitates as a detectable spot on the support. The invention includes the substrate composition and a kit of materials for performing the assay.

Abstract: A nitrogen test kit for determining the relative level of nitrogen of a user who is involved in a health program where diet and exercise are monitored and adjusted for optimizing physical development, the kit including a plastic stick having a reagent zone on which is included a reactant such as urease, and a pH indicator such as bromthymol blue, used in conjunction with color chart blocks representing a range of urea nitrogen concentrations, wherein the user's urine nitrogen content can be determined by comparing the altered color of the reagent zone of an exposed test strip to the color chart and compared with a personal baseline level, developed from a number of tests under controlled conditions, for determining the present protein nitrogen turnover and approximate balance.

Abstract: Single or multiple blood plasma component concentrations are measured by a disposable stick having one or more blood plasma component reactive areas covered by a semipermeable membrane which is permeable by blood plasma or serum components and impermeable by blood cellular and particulate matter. A second overlay may be superposed with the semipermeable membrane over the reactive areas to receive a blood sample and meter and distribute that sample uniformly to the semipermeable membrane which in turn passes the plasma components uniformly to the reactive areas. The overlays are subsequently separable from the reactive area to remove the cellular components and particulate matter and expose the reactive areas for inspection by, for example, color comparison to standardized charts.

Abstract: A stabilizer for maintaining a constant level of CO.sub.2 in coenzyme containing enzymatic CO.sub.2 diagnostic reagents is disclosed, comprising rate-limiting amounts of (a) the diagnostic reagents and (b) coenzyme-regenerating reagents, e.g., wherein (a) is malate dehydrogenase, phosphoenolpyruvate carboxylase and NADH, and (b) is glucose dehydrogenase and glucose, as are methods of use and kits containing a diagnostic reagent and stabilizer.

Abstract: This process is essentially characterized by enzymatic reactions which are carried out under anaerobic conditions between a liquid growth medium for mycoplasms containing a dilution medium of the sample of fluid to be analyzed and, on the one hand, a first substrate comprising dehydrated urea or glucose in the presence of a color pH indicator also in dehydrated form and, on the other hand, a second substrate comprising arginine also in dehydrated form or glucose in the presence of a color pH indicator and that the speed of the enzymatic response is followed while noting the time corresponding to the color change of the indicators, the respective quantities of urea and arginine or of glucose, on the one hand, and the concentration and the nutrient composition of the said growth and dilution medium, on the other hand, being first selected and standardized in such a way that for Ureaplasma urealyticum present at a supra or sub-pathological rate, the color change of the indicator is or is not obtained after a giv

Abstract: The method makes use of the action of the co-enzyme in the production of H.sub.2 O.sub.2 associated with the reaction of a hydroxylase with a decoupling agent in the presence of air or oxygen, the H.sub.2 O.sub.2 being subsequently determined by quantitative breaking of the C--F bond of a fluorinated compound in the presence of peroxidase, followed by electrometric titration of the resulting ions.

Abstract: A novel chromogenic substrate to peroxidase enzymes is provided which is comprised of a mixture of a colorless mixture of two compounds, such as, 3-methyl-2-benzothiazolinone hydrazone and 2-hydroxy-2,4,6-cycloheptatrienone, which undergo an oxidative coupling in the presence of peroxidase and hydrogen peroxide forming a purple indamine dye. Under certain circumstances the dye will precipitate out from the buffered solution and thus provide a permanent record of the determination. The mixture is also stable and unaffected by oxygen of the air or by hydrogen peroxide.

Abstract: A method for the simultaneous determination of glucose and urea in a specimen with a single reagent system. A reagent system containing a reactant for each of glucose and urea to be determined is added to a specimen. The reagent system is reacted with the specimen such that each of glucose and urea react with their respective reactant simultaneously. Each reactant is selected such that it is capable of giving an absorbance band for glucose and urea which permits their simultaneous determination. The change in absorbance or fluorescence of the resulting reaction mixture is monitored at a plurality of wavelengths which are characteristic for each of glucose and urea.

Abstract: The sample for analysis containing the co-enzyme to be detemined, inter alia NADH or NADPH, is placed in the presence of a fluorinated aromatic compound. In the presence of oxygen and peroxidase, the fluorinated compound releases fluoride ions at a rate proportional to the quantity of co-enzyme to be determined. The thus-formed F.sup.- ions are determined, thus obtaining the desired result.

Abstract: A method of enrichment and isolation of urease producing organisms from a contaminated specimen by first homogenizing the contaminated specimen in water, then introducing the homogenized contaminated specimen into a solution of urea in an acid, wherein some of the organisms are killed by the acidic medium and remaining organisms are protected from acid attack by creating a protective ammonia by breaking down the urea, and plating the remaining organisms onto a medium which contains antibiotics inhibitory to some of the remaining organisms, but not inhibitory to organisms to be isolated.

Abstract: A urine specimen is preserved from bacterial deterioration as to relative constituents by adding thymol. To the thymol-treated specimen, lithium-solution volume-marker is added, then is divided into two (first and second) separate portions. Thereupon, using the first portion, standard conventional measurements and/or analysis is conducted for total volume, pH/acidity, uric acid, citrate, sodium, and potassium. To the second portion, there is added boric acid and hydrochloric acid, followed by standard/conventional measurement and/or analysis for ammonium ion, citrate, calcium, magnesium, phosphorus, oxalate and sulfate. Thereafter the findings are charted and compared to controls.

Abstract: An antigen for the detection of Compylobacter pylori infections and an assay for the serological detection of Campylobacter pylori. The antigen includes high molecular weight cell-associated proteins purified from Campylobacter pylori. The antigen can be used in a variety of assays including radioimmunoassay, ELISA, latex agglutination, complement fixation, and indirect hemagglutination. Furthermore, the antigens can be combined with a solid support in kit form.

Abstract: A method is disclosed for determining enzymatic activity in a liquid sample by particle agglutination or inhibition of particle agglutination.

Abstract: A method is disclosed for determining enzymatic activity in a liquid sample by particle agglutination or inhibition of particle agglutination.

Abstract: An analytical element for quantitative analysis of analyte contained in a body fluid or the like, which has at least one reagent layer comprising a reactive reagent and a binder, characterized in that a portion or whole of the binder is a polycarboxylic acid carrying a nonionic surface active agent attached through ester linkage to at least a portion of the carboxyl groups contained therein.

Abstract: Disclosed herein is a method of quantitatively measuring an oxidative substance with avoiding influences of a coloring-interfering substance in the quantitative measurement of the oxidative substance by using a triphenyl methane type leuco coloring matter as a coloring reagent. Disclosed herein is also such an oxidative quantitative measurement in which the coloring sensitivity can be further adjusted. In order to avoid the influences of the coloring-interfering substance, there is employed at least one kind of (i) uricase, (ii) an anionic surface active agent and (iii) a metal chelate compound. As the triphenyl methane type leuco coloring matter, use may be made of a compound of the general formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be the same as or different from one another, represent a hydrogen atom or a lower alkyl group, and X.sub.1 and X.sub.2, which may be the same as or different from each other, represent a hydrogen atom, --SO.sub.3 M.sub.1, --COOM.sub.2, --O(CH.

Abstract: Dry chemistry reagent system, kit and method for detection of an analyte such as glucose, cholesterol, urea, antigen or antibody. The reagent system is a porous membrane or bibulous film having a porosity gradient from one planar surface to the other. In the membrane are uniformly distributed an indicator, a flow control agent and a reagent cocktail. The membrane is also modified by a conditioning agent.

Abstract: A device for use in detecting or determining the presence of antigenic or haptenic substances or antibodies in a sample comprises a plurality of tubular or capillary elements (1, 2, 3, 4, 5, 6), each having antibodies or antigenic or haptenic substances attached to an internal surface thereof, and means (11) for causing fluids to pass simultaneously or sequentially through the plurality of capillary elements. A method and test kit for detecting and determining the presence of antigenic or haptenic substances or antibodies in a sample by the enzyme-linked immunosorbent assay technique is characterized by use of urease as the enzyme in an antibody-enzyme or antigen-enzyme conjugate, with urea being used as the enzyme substrate and the presence of ammonia being detected or determined using di-bromo-o-cresolsulfonphthalein.

Abstract: Compositions for diagnosis of gastrointestinal disorders comprising urea, a bactericide, an indicator having a pK.sub.a of from about 6.5 to about 8.5, and water, wherein the composition has a pH of from about 5.0 to about 6.5 and wherein the pH is at least about one pH unit lower than the pK.sub.a of the indicator. Preferably the compositions contain a gelling agent, such as agar. Also preferably the composition contain a buffer. The invention also provides methods for diagnosis of gastrointestinal disorders in a human or lower animal subject, comprising the steps of obtaining a sample of gastric material from the subject, contacting the sample with a composition of this invention, and observing any color change, wherein a color change indicates the presence of a gastrointestinal disorder. Also provided are devices for use in diagnosis of gastrointestinal disorders.

Abstract: Urea, creatinine, creatine, triglycerides, or the like in a specimen can be accurately determined by terminating an isocitrate dehydrogenase reaction by addition of ATP and/or a chelating agent in a system wherein NAD.sup.+ formed from NADH is reproduced into NADH in the conjoint presence of an isocitrate, metallic ions such as magnesium or manganese ions, and isocitrate dehydrogenase in assaying a substance by means of a reaction of NADH to NAD.sup.+.

Abstract: A multi-layered, chemical analysis material for analysis of an aqueous liquid, which comprises in one embodiment(a) a light-transmitting, water-impermeable support having provided thereon in sequence(b) a reagent layer and(c) a porous, sample-spreading layer, with(i) the reagent layer (b) containing a lake dye precursor dispersed in a hydrophilic binder,(ii) urease incorporated in the reagent layer (b) or in a layer adjacent the reagent layer (b), and(iii) a lake forming metal salt or lake forming metal oxide, which does not substantially inhibit the activity of urease, incorporated in the reagent layer (b) or in a layer adjacent the reagent layer (b) or a lake forming metal salt or oxide incorporated in a layer adjacent the reagent layer (b); and in a second embodiment the chemical analysis material includes(d) a radiation-blocking layer interposed between said reagent layer (b) and said porous, sample-spreading layer (c).