Biotin-deficient rats were raised on a purified ration containing raw egg white plus avidin. Urea synthesis and excretion were compared between the biotin-deficient and the pair-fed control rats. 24hrurinary urea excretion and the specific activities of carbamylphosphate synthetase, ornithine transcarbamylase, and arginase in the liver mitochondria fraction were no different between these two groups. The net urea production in the liver slice and in the isolated perfused liver of the biotin-deficient rats was similar to that of the pair-fed control. Thus the conclusion must be that biotin is not in urea in mea biosynthesis in the rat.
Animal ; Avitaminosis/metabolism ; Biotin* ; Liver/metabolism* ; Rats ; Urea/biosynthesis* ; MH - ; Substances: ; Urea ; Biotin

PURPOSE: To assess the value of CT for the differential diagnosis of malignant ovarian tumors. MATERIALS AND METHODS: We reviewed CT scans of 31 patients with surgically confirmed 46 malignant ovarian tumors. (29 epithelial tumors, 9 Krukenberg tumors, 6 germ cell tumors, and 2 sex cord-stromal tumors.) CT scans were evaluated for the mass (bilaterality, size, internal component, and margin), peritoneal spread pattern, ascites, invasion of adjacent organ, and lymphadenopathy. RESULT: Bilateral masses were seen in epithelial or Krukenberg tumor in 61.1%(11/18) and 80%(4/5) respectively. Epithelial tumors showed predominantly cystic mass(37.9%, 11/29), irregular margin(82.8%, 24/29) of mass, and accompanying peritoneal and omental spread (66.7%, 12/18), whileKrukenberg tumor showed predominantly solid mass(55.5%, 5/9), smooth margin of mass(100%, 5/5), and no peritoneal and omental spread. All cases with germ cell tumor or sex cord-stromal tumor showed unilateral mass. Relatively young aged, unilateral solid (66.7%, 4/6) tumors were germ cell tumor. Of these cases, septa within solid portionof mass were prominent in all dysgerminoma. (3/3) CONCLUSION: CT may be a valuable tool for the differential diagnosis of malignant ovarian tumors.
Diagnosis, Differential* ; Dysgerminoma ; Humans ; Krukenberg Tumor ; Lymphatic Diseases ; Neoplasms, Germ Cell and Embryonal ; Sex Cord-Gonadal Stromal Tumors ; Tomography, X-Ray Computed