It is estimated that 20% of the world’s population will develop gallstones at some point in their life. Gallstones are most common in the United States and Western Europe, however the incidence is increasing in developing nations also. Risk factors in the development of gallstones include diets high in fat, low in fiber, rapid weight loss, and the use of birth control pills. Women are more likely to develop gallstones than men, especially women who have had multiple pregnancies.

The gallbladder is a small sac that stores the bile secreted by the liver. During a meal the gallbladder contracts to send bile to the intestines to aid in the digestion of fats. The main components of the bile are bile salts, bilirubin, and cholesterol (figure 1). The bile salts enable the cholesterol to remain in solution. If the amount of cholesterol in the gall bladder increases, or if the amount of bile salts decrease, the bile salts become saturated with cholesterol and then the cholesterol begins to come out of solution to form gallstones.

Gallstones can cause severe abdominal pain, nausea, and vomiting. The stones can block the bile duct and lead to fatal complications if surgery is not performed. In the United States, gallstone removal surgery is performed approximately 500,000 times each year. An alternative to surgery involves dissolving gallstones in vivo by administering bile acids orally or by injecting methyl-tert-butyl ether directly into the gallbladder.

Figure 1.

Cholesterol isolated from human gallstones contains small amounts of 3-cholestanol, 7-cholesten-3-ol, and 5,7-cholestadien-3B-ol (figure 2). Crystallization is not a feasible method of separating these compounds from cholesterol because their solubilities are so similar.

Figure 2.

Conversion of cholesterol to cholesterol dibromide enables the separation of these compounds. The cholesterol dibromide is sparingly soluble....

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