One of the major differences between DNA and RNA is the sugar, with 2-deoxyribose being replaced by the alternative pentose sugar ribose in RNA. The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T).ne of the major differences between DNA and RNA is the sugar, with 2-deoxyribose being replaced by the alternative pentose sugar ribose in RNA. The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T).
Common bile duct stone, also known as choledocholithiasis, is the presence of gallstones in the common bile duct (thus choledocho- + lithiasis). This condition causes jaundice and liver cell damage, and requires treatment by cholecystectomy and/or ERCP. 1  1 Signs and symptoms.  2 Causes.
Am J Gastroenterol. 2000;95(4):897. 1  Conventionally, the upper limit of normal for the common bile duct as measured by ultrasound is considered to be 6 mm. This review is a somewhat personalized account of how that number became the convention and cautions the reader to avoid being slavish in the use of this number.