Abstract: The object of the present invention is to provide a method for analyzing double stranded DNA directly without denaturation.

Abstract: A method of detecting nucleic acid fragments in plural samples is performed by the steps of: attaching an electroconductive label to nucleic acid fragments in one sample and attaching a different electroconductive label to nucleic acid fragments in another sample; preparing a mixture of these samples; spotting the mixture on an electroconductive microarray having plural electrodes onto which probe molecules complementary to the nucleic acid fragments are fixed, so that hybridization between the nucleic acid fragments and the probe molecules on the electroconductive microarray can proceed to form hybrid structures; applying to the electrode an electric potential corresponding to the oxidation-reduction potential of the former label and detecting on the electrode an electric current; applying to the electrode an electric potential corresponding to the oxidation-reduction potential of the latter label and detecting on the electrode an electric current; and comparing the electric current detected in the former de

Abstract: A method of analyzing a nucleic acid fragment sample to judge whether the nucleic acid fragment sample is uncomplementary, partly complementary or complementary to a DNA fragment in its specific base sequence is conducted by the steps of: bringing an aqueous solution of the nucleic acid fragment sample into contact with a DNA chip having an electroconductive substrate and the DNA fragment fixed onto the substrate in the presence of an electrochemical thread intercalator; measuring an electric current flowing from or to the electroconductive substrate along the DNA fragment under application of a potential to the substrate; and comparing the electric current measured above with a referential electric current which is prepared employing a DNA chip equivalent to the above DNA chip, the intercalator, and an aqueous solution of a nucleic acid fragment which is complementary to the DNA fragment of the DNA chip.

Abstract: A compound of the following formula: Ea—La—X—Lb—Eb in which each of Ea and Eb independently is a group having oxidation-reduction activity and having a conjugated system in its group; X is a divalent cyclic group; and each of La and Lb independently is a group which does not form a conjugated system in combination with the conjugated system of each of Ea and Eb and at least one of which has a site imparting water solubility to the compound or a site that is convertible into a site imparting water solubility to the compound, is favorably employable as an electroconductive threading intercalator in an electrochemical method for detecting complementary DNA fragments.

Abstract: A micro-array for analysis of DNA is prepared by the steps of spotting onto a solid carrier in its predetermined area in which plural reactive groups are fixed an aqueous solution which contains a thickening agent and probe molecules (e.g., DNA fragments) having a group reactive with the reactive group of the solid carrier to produce covalent bonding; spotting onto the solid carrier in a different area having the same reactive groups an aqueous solution (same or different); incubating the aqueous solution-spotted solid carrier to produce the covalent bondings; and washing the solid carrier with an aqueous medium to remove the thickening agent from the solid carrier. An electrostatic bonding can be utilized in place of the covalent bonding.

Abstract: A compound of the following formula:

Abstract: A nucleic acid detective means composed of an electrode and plural peptide nucleic acids which are fixed onto the electrode via covalent bonding is favorably employed for electrochemically detecting complementary DNA fragments The covalent bonding between the electrode and the peptide nucleic acids are favorably produced by the reaction between a reactive hydrogen-containing group attached to the peptide nucleic acid and a vinylsulfonyl group or a reactive precursor thereof attached to the electrode.

Abstract: A method of for testing complementation of nucleic acid fragment is performed by the steps of:

Abstract: A water-soluble fluorescent intercalator compound having the formula:

Abstract: A reactive solid carrier favorably employable for manufacturing DNA chip is composed of a solid carrier and a plurality of vinylsulfonyl groups or their reactive precursors each of which is fixed onto a surface of the solid carrier by covalent bonding via a linking group, and a method for producing a DNA chip is performed by bringing the reactive solid carrier into contact with nucleotide derivatives or their analogues having a reactive group which is reactive with the vinylsulfonyl group or reactive precursor fixed to the solid carrier.

Abstract: One sigmoid calibration curve is split into three parts of low concentration region represented by a high degree function, intermediate concentration region represented by an exponential function and high concentration region represented by a high degree function according to the present invention. The boundary condition of the adjacent two functions is set so that the two functions have an equal slope at the boundary point; thereby, regression functions of the calibration curves in respective regions are found. The number of standard samples for finding a calibration curve can be reduced while the calibration curve found is of high accuracy.

Abstract: An analysis element for analyzing both amounts of glycated hemoglobin and total hemoglobin in an aqueous liquid sample to determine glycated hemoglobin content ratio in the sample. The element comprises a substrate layer for receiving a reaction mixture after the completion of an immunological reaction between the glycated hemoglobin in the sample and an enzyme-labelled antibody against the glycated hemoglobin, and a reagent layer. The substrate layer contains a non-diffusible substrate which forms a diffusible material in the presence of the enzyme of the enzyme-labelled antibody, the activity of the enzyme being effected relative to the steric hindrance due to the immunological reaction. The reagent layer contains a reagent composition for reacting with the diffusible material to form a dye detectable colorimetrically in a wavelength range which is not effected by an absorption spectrum of the hemoglobin.

Abstract: One sigmoid calibration curve is split into three parts of low concentration region represented by a high degree function, intermediate concentration region represented by an exponential function and high concentration region represented by a high degree function according to the present invention. The boundary condition of the adjacent two functions is set so that the two functions have an equal slope at the boundary point; thereby, regression functions of the calibration curves in respective regions are found. The number of standard samples for finding a calibration curve can be reduced while the calibration curve found is of high accuracy.

Abstract: An immunoassay element for quantitatively analyzing a ligand by determining the change in enzymatic activity caused by a reaction between the ligand, a linked product of the ligand and a high molecular weight compound and an enzyme-labelled antibody. The immunoassay element comprises a substrate layer containing a non-diffusible substrate which forms a diffusible material in the presence of the enzyme, and a reagent layer containing a fragmenting enzyme for further fragmenting the non-difussible material. Also provided is a process for quantitatively analyzing a ligand contained in a sample by the use of the immunoassay element.

Abstract: In a method for mixing a small amount of a liquid sample with a second liquid, the liquid sample is first fed into a mixing vessel. Thereafter, the second liquid is discharged from an orifice of a second liquid pipette tip into the vessel, and the liquid sample and the second liquid are thereby stirred with each other. The small amount of the liquid sample is thus efficiently stirred by the second liquid and is thereby uniformly mixed with the second liquid. Also, the liquid sample and the second liquid are mixed with each other in an accurate mixing ratio.

Abstract: An integral multilayer analytical element in which a first fibrous porous layer, a nonfibrous porous layer, and a second fibrous porous layer superposed in this order on a water-impermeable light-transmissive support the first fibrous porous-layer having a larger pore size than the nonfibrous porous layer. The above three porous layers are integrally laminated to each other substantially closely by an adhesive discontinuously disposed so as to form microspaces continuing through from one layer to the next so as not to interfere with the approximately uniform permeation of liquid. A reagent composition which produces an optically detectable change in the presence of an analyte is incorporated in at least one of said three porous layers. When a nonporous reagent layer is incorporated on the support in the above analytical element, the reagent composition is incorporated in the nonporous reagent layer.

Abstract: In a dry type analytical element having at least one water-permeable layer including a porous spreading layer and at least one water-permeable layer, containing an enzyme having cholesterol esterase activity, the improvement which comprises containing a condensate of poly(ethylene oxide) monoalkylphenyl ether and formaldehyde at least in the water-permeable layer containing the enzyme or another water-permeable layer. In the analytical element of the invention, hemolysis does not occur and bound cholesterol is sufficiently decomposed to free cholesterol.

Abstract: A method of quantitatively analyzing an analyte contained in a whole blood sample, wherein a dry multi-layered analysis element is used. The method provides particular merits when the used multi-layered analysis element has no light-shielding layer which is interposed, in the conventional analysis element, between a coloring reagent layer and a blood cell separating layer, so that red coloring matters of blood cells are detected from the support side during the step of measuring the optical density of the reflected light.

Abstract: An electrophoretic method comprises the steps of positioning a sample, which contains nucleic acid fragments having different numbers of bases, in an electrophoresis medium composed of an electrophoresis gel medium containing an aqueous poly(meth)acrylamide gel prepared by cross-linking polymerization of a (meth)acrylamide compound and a cross-linking agent in the presence of water and a compound having at least one carbamoyl group as a denaturing agent (or modifier), and applying pulsed electric fields to the electrophoresis medium in two directions, thereby to move the nucleic acid fragments in the presence of molecular sieve effects and to separate the nucleic acid fragments.