Kyowa Medex Co., Ltd.

Norihito Aoyama

Akira Miike

Toshio Tatano

Yoshiaki Shimizu

Minako Sakakibara

Mikio Okano

Kayoko Shigenobu

Mitsuru Tsuda

Tomoko Unno

Kinya Fujishiro

Seiji Sekine

Osamu Kusada

Ayako Kojima

Hideki Takenaka

Yoshinori Tominaga

Kazuhiko Sasaki

Katsuyuki Taga

Toshiyuki Masunari

The present invention provides a simple method for the stabilization of a peptide in a biological sample and a reagent for the stabilization, a simple method for the preservation of a biological sample comprising a peptide and a reagent for the preservation, and a method for the accurate measurement of a peptide in a biological sample and a reagent for the measurement. Addition of a saccharide to a biological sample enables the stabilization of a peptide in the biological sample, the preservation of the biological sample comprising a peptide in a stable condition and the accurate measurement of a peptide in the biological sample. As the present invention can stabilize a peptide in a biological sample collected in the clinical examination, the peptide as a marker in the biological sample can be measured accurately in the clinical examination.

Method for stabilization of peptides in a biological sample

Determining ascorbic acid using ASOD and LEUCO chromogen

The present invention relates to a method for quantitatively determining a peroxidation-active substance, hydrogen peroxide or a coumarin derivative represented by formula (I) or (II): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are the same or different and each represents hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted aralkyl, substituted or unsubstituted aryl or halogen; the method comprising reacting the hydrogen peroxide with the coumarin derivative represented by formula (I) or (II) or its salt in the presence of the peroxidation-active substance, and determining the amount of the light emission or the light intensity from the reaction solution.

Method of quantitative determination of substances using coumarin

The object of the invention is to provide a reagent for quantitatively determining creatine kinase with improved storability in liquid form as well as a method for quantitatively determining creatine kinase with stable measurements. Disclosed are a method for quantitatively determining creatine kinase, which comprises activating creatine kinase in a sample in an aqueous medium in coexistence with a trivalent phosphorus compound and a sulfhydryl-containing compound and then determining creatine kinase activity; a method for stabilizing a sulfhydryl-containing compound, which comprises allowing a trivalent phosphorus compound to coexist with a sulfhydryl-containing compound; and a reagent for quantitatively determining creatine kinase, which comprises a trivalent phosphorus compound, a sulfhydryl-containing compound, and a reaction substrate for creatine kinase.

Method for quantitatively determining creatinine kinase and a reagent

Disclosed is a chemiluminescent method of quantitatively determining one of peroxide, a peroxidation-active substance or a pyrazolopyridopyridazine derivative represented by the formula (I): ##STR1## wherein R.sup.1 represents hydrogen, lower alkyl, optionally substituted aryl, optionally substituted heterocyclic group, substituted sulfonyl, substituted sulfinyl, substituted thio etc.; R.sup.2 represents hydrogen, lower alkyl, optionally substituted aryl, etc., or a salt thereof; characterized by subjecting an unknown amount of one substance selected from the peroxide, peroxidation-active substance and pyrazolopyridopyridazine derivative to react with a known amount of the remaining two substances.

Method of quantitative determination of peroxide, a peroxidation-active

Disclosed is a method for stably storing a liquid diagnostic reagent, comprising air-hermetically keeping the liquid diagnostic reagent in a closed container in the presence of a disoxidant therein. Preferably, at least one of the liquid diagnostic reagent and the disoxidant is covered with a separating container made of a material pervious to oxygen but not to solutions. The liquid diagnostic reagent may comprise an enzyme or an indicator.

Method for storing liquid diagnostic reagents

Method of quantitative determination of sodium ions

A method for stabilizing urease in an assay reagent for determination of urea nitrogen in a sample and a method for accurately determining urea nitrogen in a sample are disclosed. After urea nitrogen in the sample is reacted with urease in the presence of an organic boron compound, the amount of ammonia formed by the reaction is determined.

Method for determination of urea nitrogen

A method for quantitating accurately 1,5-anhydroglucitol, fructose or amylase in a sample that contains galactose using an enzymatic determination involves a pretreatment which removes galactose from the sample by an enzyme reaction in which galactose is a substrate.

Method for enzymatic determination of substrate after enzymatically

Glucose 6-phosphate dehydrogenase is stabilized in a clinical assay reagent with at least one stabilizer selected from among hydroxylamines, aldehyde scavengers dimethylthiocarbamoyl chloride, 2-(2-aminoethylamine) ethanol, and their salts. The reagent may be in liquid or lyophilized form.

Method for stabilizing glucose 6-phosphate dehydrogenase with

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.

Peroxidase catalyzed enzyme assay by sample PRG-treatment

The present invention provides a method for the determination of a compound having mercapto group which comprises reacting the compound with a chromogen represented by the following general formula (I): ##STR1## wherein Y is hydrogen or hydroxyl; R.sub.1, R.sub.2 and R.sub.3 may be the same or different, and are groups represented by the following general formula (II), (III) or (IV): ##STR2## wherein Z (which may be the same or different) is hydroxyl, amino, substituted amino, alkyl, substituted alkyl, alkenyl, aryl, substituted aryl, acyl, halogen, nitro, sulfo, carboxyl or alkoxy; n is 0, 1, 2, or 3; provided that at least one Z in R.sub.1, R.sub.2 and R.sub.3 is hydroxyl, amino, or substituted amino, in the presence of peroxidase or thiol oxide reductase, and determining the pigment thus formed.

Method for the determination of the compound having mercapto group

Disclosed is a method for the colorimetric determination of hydrogen peroxide in a sample by reacting a particular chromogen with the hydrogen perioxide in the presence of peroxidase and measuring the absorbancy of the reaction solution in the visible or near inflared ray region. Also disclosed is a test composition for carrying out the determination.

Method and test composition for determination of hydrogen peroxide

The present invention provides a method for the determination of NAD(P)H which comprises reacting a chromogen represented by the following general formula (I): ##STR1## wherein Y is hydrogen or hydroxyl; R.sub.1, R.sub.2 and R.sub.3 may be the same or different, and are groups represented by the following general formula (II), (III) or (IV): ##STR2## wherein Z is hydrogen, hydroxyl, amino, substituted amino, alkyl, substituted alkyl, alkenyl, aryl, substituted aryl, acyl, halogen, nitro, sulfo, carboxyl or alkoxy; n is 1, 2, or 3; provided that at least one Z in R.sub.1, R.sub.2 and R.sub.3 is hydroxyl, amino, or substituted amino; and Z.sub.s in Z.sub.n may be the same or different, with NAD(P)H in the presence of (1) peroxidase or thiol oxide reductase and (2) diaphorase or an electron carrier, and determining the pigment thus formed.

Method for the determination of the reduced form of nicotinamide adenine

A method and test composition for colorimetrically determining hydrogen peroxide in a sample includes a chromogen of the formula: ##STR1## which is reacted with hydrogen peroxide in the sample in the presence of peroxidase. The absorbancy of the reaction solution is then measured.

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Shizuoka, Japan

Norihito Aoyama