Urachal

Pyrimidines A family of 6-membered heterocycHc compounds occurring in nature in a wide variety of forms. They indude several nudeic add constituents (cytosine, thymine, and uracH) and form the basic structure of the barbiturates. [NiH]... 

URACA Pumpenfabrik GmbH + Co. KG Sirchinger Str. 15, 72574 Bad Urach, Germany... 

FIGURE 8.16 Urachal cyst (hematoxylin and eosin stain) (A). CDX2 positive nuclei in this urachal remnant (B) from the dome of the bladder confirm the gastrointestinal origin of this cyst. 

Adenocarcinomas of urinary bladder (urachal origin) are CDX2-I- but are also positive for thrombomodulin and CK7, whereas colorectal carcinomas are negative with thrombomodulin and CK7 and have nuclear beta-catenin expression. 

Golz R, Schubert GE. Prostatic specific antigen immunoteactiv-ity in urachal remnants. J Urol. 1989 141 1480-1482. 

Other examples of cross-reactive staining include anal glands in men (PSA, PSAP) and urachal remnants... 

CT and US may demonstrate a low attenuating lesion or an anechoic defect typically located in the tail of the pancreas. This lesion can be unilocular or multilocular with multiple septae. The differential diagnosis includes cyst of renal origin, as well as choledochal, mesenteric, ovarian, and urachal cysts. ERCP and HIDA scans can be used to identify communication with the pancreatic duct or biliary tree. 

Alanine could be formed via the oxidation of propionic acid (Stadtman, 1955), the oxidation of spermine or spermidine (Razin et al., 1958), the catabolism of pyrimidines (Barnes and Naylor, 1962), and the decarboxylation of aspartate (Virtanen et al., 1938). While there is little evidence in higher plants for the formation of /3-alanine via aspartate decarboxylation (Naylor al., 1958) uracH has been shown to be catabolized (via carbarnyl-/3-alanine) to /3-alanine (Barnes and Naylor, 1962 Tsai and Axelrod, 1965 Pitel and Durzan, 1975). 

The author wishes to thank URACA, D7432, Bad Urach for their assistance in preparing this section. 

The urachus is the remnant of an embryonic connection coursing from the dome of the fetal bladder to the umbilicus. After birth in normal children, it is limited to a thin cord-like structure. Rarely, a patent urachus is present at birth. More commonly, urachal diverticulum is present at the dome of the bladder (Fig. 6.15). Diagnosis can be made on VCU on lateral views. An urachal cyst is another pathogenic remnant of an urachus. It may be isolated or multiple. Infection can occur (Newman et al. 1986). Diagnosis is based on the association of clinical findings and ultrasound, which shows a superficial midline abscess-like structure. Urachal carcinoma does not occur in childhood (Thomas et al. 1986), but this possible complication in adulthood justifies surgical excision of urachal cysts in children. 

Gobet R, Bleakley J, Peters CA (1998) Premature urachal closure induces hydroureteronephrosis in male fetuses. J Urol 160 1463-1467... 

Newman BM, Karp MP, Jewett TC et al (1986) Advances in the management of infected urachal cysts. J Pediatr Surg 21 1051-1054... 

Thomas AJ, Pollack MS, Libshitz HI (1986) Urachal carcinoma evaluation with computed tomography. Urol Radiol 8 194-198... 

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