Calcium bilirubinate

Biliary sludge A deposit of tiny stones or crystals made up of cholesterol, calcium bilirubinate, and other calcium salts. The cholesterol and calcium bilirubinate crystals in biliary sludge can lead to gallstone formation. 

Second, albumin is a non-specific carrier protein. A wide range of chemically disparate compounds are bound loosely to albumin for transport through the blood stream. Important examples include calcium, bilirubin, drugs and free fatty acids. 

Part of the cholesterol newly synthesized in the liver is excreted into bile in a free non-esterified state (in constant, amount). Cholesteiol in bile is normally complexed with bile salts to form soluble cholic acids, Free cholesterol is not readily soluble and with bile stasis or decreased bile salt concentration may precipitate as gallstones. Most common gallstones are built of alternating layers of cholesterol and calcium bilirubin and consist mainly (80-90%) of cholesterol. Normally. 80% of hepatic cholesterol arising from blood or lymph is metabolized to cholic acids and is eventually excreted into the bile in the form of bile salts. 

Components of gallstones Cholesterol, calcium bilirubinate, and bile... 

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. 

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. 

Fig. I8.I0. Infrared spectrum of authentic calcium bilirubinate showing the baseline for measuring the absorbance at l624cm .(Toyoda, 1966.)...

Calcium has been recognized as a constituent of gallstones since the earliest chemical studies (see reference 118). It occurs as calcium carbonate (either calcite or aragonite), calcium phosphate (apatite), calcium bilirubinate, or the salts of bile acids and fatty acids. In normal hepatic bile, the calcium concentration is about 21 mg %. It is about 45 mg % in normal gallbladder bile and about twice that in the gallbladder bile of patients with cholesterol stones (119). The concentration of calcium is said to vary with the concentration of bile salts (3). Apparently, calcium in bile is bound in part to bile salt micelles, and under normal conditions this complex remains stable and soluble (120). However, under appropriate conditions of pH, calcium concentration, and anion concentration, calcium salts may precipitate. 

Usuki (169) raised rabbits on a diet deficient in fat-soluble vitamins and found a 9% incidence of gallstones after 6-8 weeks. Qualitative analysis revealed that these small sandlike stones contained calcium, bilirubin, and traces of cholesterol. 

Constituents of human gall stones are cholesterol and calcium bilirubinate. 

As is often the case for biological products, the term pure is a misnomer no stones are made of pure cholesterol or concentric layers of pure cholesterol and calcium bilirubinate. Stones often contain other components such as iron, proteins, and mucopolysaccharides. In fact, even the purest cholesterol stones seem to contain small amounts of protein or polysaccharide at their center, a finding that is in keeping with the concept that gallstones, like kidney... 

Examples of secretions appear in bile (Sato, 1962 Matsushiro, 1963) Tenhunen, 1965) and intestinal juice (Karunairatnum and Levvy, 1951 and sometimes in salivary secretions (Yamanaka et al., 1965 Murata and Miyaji, 1966 Harvey et at., 1966). Judging from its properties, e.g., pH, -glucuronidase activity in these fluids is probably due in part to bacterial infection. /S-G ueuronidase in bile probably plays some role in the entero-hepatic circulation of drugs (Williams el al., 1965) and hormones (Paschkis and llakoff, 1950 Knapstein et cU., 1966, 1967), and also may induce the formation of calcium bilirubinate stones (Maki el al., 1962 Saito, 1964 Sato el al., 1964 Maki, 1966). 

The mechanism of calcium bilirubinate stone formation by bacterial jS-glucuronidase has been proposed by iUaki et al. (Maki, 1966 Haki and Sato, 1966) as follows the enzyme hydrolyzes bilirubin glucuronide to yield free glucuronic acid and bilirubin, and calcium in bile at the carboxyl radical of liberated bilirubin forms calcium bilirubinate stone. 

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