Relevance of a circulating immune complex assay (CIC) to distinguish between patients with autoimmune thyroid diseases and healthy controls (ELISA, C 1q, Anti-C 1q, IgM, IgG)

Abstract

Acidic solutions of both caffeine and theobromine exhibit absorption spectra of similar nature and magnitude with maxima near 273 mμ. If the solutions are made basic there is little change in absorption for the caffeine but the theobromine shows a considerable increase in absorption in the region of 220–254 mμ. For each constituent, the concentration is proportional to absorbancy for a given set of conditions. In mixtures, the amount of theobromine can be calculated directly from the difference in absorbancy observed for the basic and acidic solutions at 240 mμ. Knowing the amount of theobromine, its absorbancy in acid solution at 273 mμ may be calculated and the residual absorption observed gives a measure of the amount of caffeine present. As an alternate procedure, the quantities of each may be calculated by the solution of simultaneous equations involving the absorbancies at 240 and 273 mμ in basic solution. Representative experimental data and results for the mixtures of varying proportions in a total concentration of 30 mg. per liter are shown.