Chemistry of the Van Den Bergh Reaction
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چکیده
The form in which bilirubin exists in the blood is of considerable interest because of the observed differences in the van den Bergh reaction in disease and because of the relation of bilirubin to hemoglobin metabolism. All of the bilirubin in plasma reacts in 30 minutes with diazonium salts in acid 50 per cent methyl alcohol to give a red dye (1). A variable fraction of the total reacts with varying rapidity in aqueous acid (“direct” reaction). Clinically the size of this fraction is of some diagnostic value in distinguishing obstructive from hemolytic jaundice. Nearly all of the many theories propounded to explain the differences among plasmas from cases of jaundice in the percentage of the total bilirubin which reacts in aqueous acid can be divided into two classes, (1) those which postulate that the bilirubin not reacting in aqueous acid is prevented from doing so by a definite valence bond to a fraction of the plasma proteins presumably derived from hemoglobin, and (2) those which postulate that catalytic or inhibiting substances present in various amounts produce variations in the per cent of bilirubin giving the direct (aqueous) reaction. Most of the experiments designed to support the latter type of theory have been synthetic, involving Dhe construction of models apparently duplicating, by the use of catalysts, the effects observed in naturally occurring jaundiced plasmas. The following experiments are an attempt at an analytical solution of the problem by means of the accurate and convenient plasma bilirubin method of Malloy and Evelyn (1). They appear to show, to the exclusion of the second type of t.heory, that in the plasma from jaundiced patients the bulirubin not reacting in
منابع مشابه
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تاریخ انتشار 2003