Analysis of Calculi Gallstones

Edwards et al. (1958) have used infrared spectroscopy in the qualitative analysis of 30 specimens of human biliary calculi. The spectra of cholesterol, calcium bilirubinate, and calcium carbonate display prominent and characteristic bands that do not overlap in certain areas of the spectrum. Bands at 3380, 2910, and 1055cm indicate the presence of cholesterol, a doublet at 1670 and 1630 cm is characteristic of calcium bilirubinate, and a sharp band at 875 cm is produced by calcium carbonate. It is thus possible to verify the principal constituents of biliary calculi—whether they are (1) pure gallstones that are composed of either cholesterol, calcium bilirubinate, or calcium carbonate, or are (2) mixed gallstones that are composed chiefly of two or three of these components, or are (3) combined llstones with a nucleus of one kind and a shell of another substance. 

Weissman et al. (1959) have analyzed renal calculi by the KBr disk method and applied the same technique to prostatic, dental, biliary tract, and salivary gland calculi, and to the identiflcation of alcohols, barbiturates, and salicylates (Klein et al, 1960). 

Recent advances in infrared spectroscopy have allowed rapid and simple determination of some gallstone ingredients (Chihara et al., 1958) with a minimum quantity of specimen. Of various absorptions characteristic of calcium bilirubinate, the one at 1624 cm , which is due to Vc c of pyrrole nuclei (Suzuki and Toyoda, 1966), was chosen as the key band for quantitative analysis. In analyses of 10 gallstone specimens (Toyoda, 1966) the infrared-determined calcium bilirubinate content was found to lie in between values from two kinds of chemical data those obtained for extracts of the stones with (a) chloroform after HCl treatment, plus a 5 % ammonia extraction, and (b) those obtained for extracts with chloroform, but no ammonia extraction. Toyoda claims that the infrared data show satisfactory proportionality with both types of data. 

Gallstones occasionally contain black pigments which consist of polymers of bilirubin derivatives. To study whether any bile pigment metal complex is also 

Addition of cupric chloride to bilirubin in sodium hydroxide solution resulted in precipitation of a black substance, which was proved to be a bilirubin-Na-Cu complex formed by coordination of copper to sodium bilirubinate. The black pigments of the gallstone may thus possibly include some metal complexes of bile pigments, although identification of such substances in the bile or in gallstones had not yet been definitely established at the time of this investigation. 

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