METHOD FOR COMPLEX ESTIMATION OF THE AMOUNT OF OXIDATIVELY MODIFIED PROTEINS IN BIOLOGICAL FLUIDS Russian patent published in 2022 - IPC G01N33/52 G01N33/68 G01N21/27 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely clinical biochemistry, and can be used for a comprehensive assessment of the amount of oxidatively modified proteins in biological fluids. The optical density of a pre-prepared sample is measured in the wavelength range of 230-535 nm, and a graph of the dependence of the optical density of the sample under study on the wavelength is plotted. The graph is divided into segments according to the wavelength ranges of absorption fractions: aldehyde dinitrophenylhydrazones of the main (ADNPHm) and neutral (ADNPHn) character and ketone-dinitrophenyl-hydrazones of the main (KDNPHm) and neutral (KDNPHn) character: ADNPHn in the range of 230-367 nm; ADNPHm - 258-264 and 428-520 nm; KDNPHn - 363-367 nm; KDNPHm - 430-434 and 524-535 nm. In each segment, when calculating the areas of optical density for each of the fractions: S_ADNPHn, S_ADNPHm, S_KDNPHn and S_KDNPHm, a numerical integration method is used - the Simpson formula: S= h/3[(y₀+4(y₁+y₃+…+y_n-1) + 2(y₂+y₄+…+y_n-2)+y_n)], where: S is the area of the optical density of one of the fractions of the sample: S_ADNPHn, S_ADNPHm, S_KDNPHn, S_KDNPHm, y₀, y₁, y₂, y₃, y₄, y_n-2, y_n-1, y_n are the optical density indicators, h is the step of the optical density interval. The total number of oxidatively modified proteins is calculated by summing the areas of the fractions of S_ADNPHn, S_ADNPHm, S_KDNPHn and S_KDNPHm.

EFFECT: method provides an opportunity to increase the accuracy of a comprehensive assessment of the content of oxidatively modified proteins in biological fluids during spectrophotometric analysis by applying a calculation method using the numerical integration method: the Simpson formula, which makes it possible to calculate the results of the study in more detail.

1 cl, 1 dwg, 2 ex