Digoxin cross-reactivity with

Inhibition of ouabain binding to membrane Na, K -ATPase and cross-reactivity with digoxin antibody in a radioimmunoassay from a pleurisy root aqueous extract were observed in vitro (Longerich et al. 1993). 

In other bioanalytical applications, the emphasis lies more on overcoming cross-reactivity. For example, the heart glycoside digoxin is cross-reactive with several of its metabolites as well as with plasma constituents, thus hampering approaches solely based on immunoassays. By treating plasma samples with sohd-phase extraction on a restricted access column, coupled online to reversed-phase LC/immunodetection, digoxin and two of its cross-reactive metabolites were analyzed in patients treated with the heart glycoside. 

Pleasants RA, Williams DM, Porter RS, Gadsden RH Sr. Reassessment of cross-reactivity of spironolactone metabolites with four digoxin immunoassays. Ther Drug Monit 1989 ll(2) 200-4. 

JJ Miller, RW Straub Jr, R Valdes Jr. Digoxin immunoassay with cross-reactivity of digoxin metabolites proportional to their biological activity. Clin Chem 40 1898, 1994. 

R Stenzel, B Reckmann. Cross-reactivity of anti-digoxin antibodies with digitoxin depends on tracer structure. Clin Chem 38 2228, 1992. 

Table 2. Cross-reactivity of monoclonal anti-digoxin antibody (64. 2B.5) with compounds structurally related to digoxin in ELISA (after Yoshimatsu et al. 1990).

Bufalin, a cardioactive substance of amphibian origin and Chinese medicines such as Chan Su, Lu-Shen-Wan and Kyushin that contain bufalin can interfere with some immunoassay methods of digitoxin and digoxin, partieularly the fluoreseenee polarisation immunoassay. " The digoxinlike immunoreaetivity of Kyushin was found to be equivalent to varying amounts of digoxin beeause of differences in the cross-reactivity of the... 

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