Patent RU-2764870-C1 (RU)
Inventor: KRUCHININA MARGARITA VITALEVNA
IPC: G01N27/48
Filed: 2021-03-30
Granted: 2022-01-21
Abstract: FIELD: medicine. 
     SUBSTANCE: invention relates to medicine, namely gastroenterology, and can be used to diagnose the degree of activity of inflammatory bowel diseases. The level of fecal calprotectin is determined as follows. Patients’ erythrocytes are sampled, samples are placed in a 3.65-3.85% citrate buffer in a ratio of 9:1, after 5-20 minutes, a sample of 9-11 µl is injected into a 0.3 M sucrose solution of 285-295 µl and mixed. The resulting cell suspension with a volume of 5-10 µl is introduced into a measuring cell, where for 2-5 seconds an inhomogeneous alternating electric field (IAEF) is formed with a frequency of ƒ 5⋅10 4 -10 6  Hz and an average electric field strength E o  in the gap between the electrodes in the range of 10 4 -10 6  V/m and a    gradient of the square of the electric field strength 10 11 -10 13  [V 2 /m 3 ]. A video recording of the behavior of cells in the measuring chamber between the electrodes is made and it is entered into a computer in a measuring and computing complex (MCC). Next, the parameters of erythrocytes are calculated:  
     х 1 =D av =(D 1 +D 2 +…+D n )/n is the average diameter of the erythrocyte, 
     where D 1  is the diameter of the first cell; 
     D 2  - diameter of the second cell; 
     D n  is the diameter of the nth cell; 
     n is the number of cells; 
         is the rate of translational movement of the erythrocyte in an electric field, 
     where S is the distance traveled by the cell during t; 
         is polarizability, 
     where     is the modulus of the square of the gradient of the electric field strength between the electrodes of the measuring cell; 
     x4=ω p1 =(ƒ p ) is the equilibrium frequency; 
        is the electrical conductivity of the erythrocyte, 
     where R c  is the resistance of the cell; 
     R m  - resistance of the medium; 
        is the generalized erythrocyte viscosity index, 
     where C c  is a generalized indicator of erythrocyte stiffness; 
     τ p  - duration of the probing radio pulse; 
     π is a constant value equal to 3.14; 
     r c  is the radius of the cell in the electric field; 
     x m  is the maximum amplitude of cell deformation; 
        is a generalized indicator of cell stiffness, 
     where α c  is the polarizability of the cell; 
     ε O  is the dielectric constant equal to 8.85⋅10 -12 ; 
     E is the electric field strength; 
     r c  is the radius of the cell in the electric field; 
     x m  is the amplitude of cell deformation;  
         is the maximum amplitude of the deformation of the cell, 
     where     is the initial diameter of the cell, before the inclusion of the IAEF; 
         is the maximum diameter of the cell when the IAEF is turned on. Then the obtained data are compared with the corresponding values of the level of fecal calprotectin and erythrocyte indices determined for a group of patients conventionally healthy without pathologies. In the presence of 60% or more different parameters from the group of conventionally healthy subjects without pathologies and within the limits of the values indicated in Table 1 of the description, patients are diagnosed with active or inactive inflammatory bowel disease.   
     EFFECT: method makes it possible to increase the specificity and accuracy of the analysis of inflammatory bowel diseases at earlier stages with the determination of variants of its preclinical manifestations by selecting and measuring the most significant electrical and viscoelastic parameters of erythrocytes in combination with the determination of the level of fecal calprotectin.  
     1 cl, 4 dwg, 2 tbl, 2 ex