[Total antioxidant capacity of biological fluids for chronic kidney insufficiency using coulometric titration data].

Express coulometric method for estimation of blood and plasma antioxidant capacity based on the use of electrogenerated compounds of bromine is proposed. Using this method we found changes in total antioxidant capacity in patient with chronic kidney insufficiency during hemodialysis session and after it.

[Amperometric enzyme immunosensor for determination of Klebsiella pneumoniae antigen].

An amperometric enzyme immunosensor for detecting the bacterial antigen Klebsiella pneumoniae has been developed. The biosensing part of this analytical device consists of cholinesterase and antibodies to Klebsiella pneumoniae co-immobilized into the cellulose nitrate membrane. The conditions of immunosensor functioning (ratio of enzyme and antibodies, substrate concentration, pH of working buffer solution) were chosen. The sensor with antibodies in dilution 1:20 demonstrated the best analytical characteristics. Working concentrations were ranged from 1 x 10(-9) to 1 x 10(-3) mg/ml, the detection limit was 5 x 10(-10) mg/ml. The cross-reactivity of used antibodies to antigens of bacteria, causing similar diseases was evaluated. The conditions of immunosensor reuse by regeneration of its biosensing part were chosen. The developed immunosensor was probed on blood sera of patients suffering from urea tract diseases.

[Competitive immunochemical determination of antigens using conjugates containing Co(II) and Ni(II)]. / Konkurentnoe immunokhimicheskoe opredelenie antigenov s pomoshch'iu kon"iugatov, soderzhashchikh iony Co(II) i Ni(II).

A new variant of competitive heterogeneous immunoassay for certain proteinaceous antigens has been developed. The assay is based on the use of the target protein conjugated with Co(II) or Ni(II) ions and immobilized Abs. The effect of catalytic hydrogen release allows quantitation of the metal ion labels by voltammetry at the final step of the assay. The conjugates have been characterized by spectrophotometry, voltammetry, atomic adsorption spectrometry, and nuclear magnetic relaxation. Based on the use of the conjugate RNase-diethylenetriaminepentaacetic acid-Co(II) (10:4:4), a competitive immunoassay for RNase has been developed, detecting the target protein in the range 2 x 10(-2)-2 x 10(-4) mg/ml.

[Noncompetitive immunochemical determination of ribonuclease using transition metal ions and the effect of catalytic hydrogen release]. / Nekonkurentnoe immunokhimicheskoe opredelenie ribonukleazy s ispol'zovaniem ionov perekhodnykh metallov i éffekta kataliticheskogo vydeleniia vodoroda.

A noncompetitive variant of immunochemical ribonuclease (RNase) determination has been developed, involving the use of Co(II) as a label. A variety of approaches to labeling the immunological reagent with the metal have been assessed. In the variant proposed, catalytic hydrogen release was used as a means of detecting the label, the amount of which was proportional to RNase concentration. Conditions making it possible to record catalytic hydrogen release fluxes were determined. In the presence of RNase, the electrocatalytic effect was maximum at a concentration of Co(II) in the ammoniac buffer, equal to 2 x 10(-4) M (pH 10.0). The dependence was linear in the range 4-2000 ng/ml RNase concentrations (threshold concentration, 2 ng/ml).

[Determination of a Candida albicans antigen using an amperometric immunoenzyme sensor]. / Opredelenie antigena Candida albicans s pomoshch'iu amperometricheskogoimmunofermentnogo sensora.

Determination new variant enzyme immunoassay with amperometric enzyme immunosensor, including the immobilizing enzyme-choline esterase and antibodies against Candida albicans (CA) in biosensitivity part of sensor, for diagnose disease of CA. The method for determination of CA based on combination immunochemical reactions and voltammetric indication of analytical signal was developed. Amperometric enzyme immunosensor developed has been used as detector. Differences dilutions of antibody (Ab) against antigen (Ag) of CA immobilizing in common with choline esterase (CE). The method of immobilization developed allows to receive the sensor with including the immobilized CE and Ab in common. The method of determination of CA based on combination the reaction of forming immune complex tAb-AgI with enzyme immunosensor for its detection. The dynamic range of concentrations determined of Ag depends on degree of dilution of Ab used for manufactory biosensitivity part of sensor. The data indicate that the [Ab-Ag] immune complexes are stable. This is also confirmed by the values of [Ab-Ag] binding constants, obtained in Scatchard coordinates. This method of determination doesn't require special preparation of a sample. Selectivity, sensitivity, simplicity and quickness are characterize of this method which could be used for manufacturing test-sistem for determination CA in blood.

[A novel use of cholinesterase amperometric biosensor for selective determination of 2,4-dichlorophenoxyacetic acid]. / Novyi variant ispol'zovaniia kholinésteraznogo amperometricheskogo biosensora dlia selektivnogo opredeleniia 2,4-dikhlorfenoksiuksusnoi kisloty.

A new method of detection of 2,4-dichlorophenoxyacetic acid by means of immobilized monoclonal antibodies and an amperometric cholinesterase biosensor is proposed. A combination of monoclonal antibodies to 2,4-dichlorophenoxyacetic acid with an enzyme electrode provides high selectivity of measurements and allows trace amounts of this pesticide to be detected within a concentration range of 1 x 10(-1) to 5 x 10(-7) M with a sensitivity threshold of 5 x 10(-12) M.