Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three rats of six males, surviving 22 to 27.5 months after one or two intragastric doses of the monoester pyrrolizidine alkaloid, heliotrine (230 mg/kg body weight), and pretreatment with nicotinamide (350 mg/kg body weight) by pretreatment with nicotinamide (350 mg/kg body weight) by i.p. injections, developed pancreatic islet-cell tumors, accompanied in one of the rats by transitory cell papillomas of the urinary bladder and interstitial testicular tumors and in another by a hepatoma. The lesions in the livers showed progression from megalocytosis, to microscopic hepatocellular hyperplasia, to increasingly larger nodules and hepatoma. One rat, given heliotrine, but no nicotinamide, also developed adenoma of the pancreatic islet cells. Adenomas of the pituitary were present among the experimental and also among the control rats killed between 19 and 27.5 months after the beginning of the experiment, and they are not likely to have been caused by the alkaloid. Heliotrine, in which the crucial double bond in the pyrrolizidine moiety is sterically hindered, appears to be less readily sequestered by the liver and also to affect other organs. Alkylation of nicotinamide at the N-1 position prevents its being reused for coenzyme biosynthesis. Hence, pretreatment of rats with large doses of nicotinamide prevents the depletion of nicotinamide adenine dinucleotide coenzymes and liver necrosis in rats given heliotrine (230 mg/kg body weight).
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PMID:Pancreatic islet-cell and other tumors in rats given heliotrine, a monoester pyrrolizidine alkaloid, and nicotinamide. 16 43

Liver carcinogenesis with a single dose of aflatoxin B1 (7 mg/kg body weight) has been investigated in a group of female Wistar strain rats by repeated biopsies and necropsies. Another group received a subsequent intoxication with carbon tetrachloride by inhalation (approximately 200 doses) and another one was overloaded with riboflavin (25 parts/10(6) in drinking water). The frequency of hepatomata was almost equal in the aflatoxin and aflatoxin-carbon tetrachloride group. It was lowere in the riboflavin-aflatoxin group. In these 3 groups cirrhosis was never present in neoplastic livers. Megalocytosis was the first lesion observed. All tumoral livers had previous or concomitant megalocytosis. This modification was about as frequent, intense and widespread in aflatoxin-CCl4 and aflatoxin groups but appeared much earlier, as did the first hepatoma, in the aflatoxin-CCl4 group. It was less frequent, less intense and less widespread in the riboflavin-aflatoxin group than in the aflatoxin group. There was also a lower frequency of hepatomata in the riboflavin-aflatoxin group, but the difference was not significant due to the too small number of animals involved. The facts are not a proof of the existence of an obligatory link between megalocytosis and carcinogenesis since a slight megalocytosis was observed in the riboflavin group not affected by the neoplastic process. However, the simplest explanation of our results would be to consider that the potential tumour cells are located among the megalocytic cells, without admitting that every megalocyte is obligatorily a precancerous cell. CCl4 seems to act in shortening the time of appearance of megalocytosis. The protective effect of riboflavine should be regarded with more caution.
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PMID:Influence of carbon tetrachloride or riboflavin on liver carcinogenesis with a single dose of aflatoxin b1. 17 84

Progression of hepatic neoplasia was assessed in medaka (Oryzias latipes) following aqueous exposure to diethylnitrosamine (DEN). Larvae (2 weeks old) were exposed to 350 or 500 p.p.m. DEN for 48 h, while adults (3-6 months old) were exposed to 50 p.p.m. DEN for 5 weeks. Fish were maintained as long as possible to determine malignant potential of resultant neoplasms. A total of 423 medaka with 106 hepatic neoplasms were examined. There were marked differences in tumor prevalence between exposure groups including: (i) higher prevalence of hepatocellular carcinomas in medaka exposed as adults (100% of hepatocellular tumors in adult-exposed medaka were malignant, while only 51.5% of larval hepatocellular tumors were malignant); (ii) higher prevalence of biliary tumors in medaka exposed as larvae (46.4% of all tumors in larval-exposed medaka were biliary versus 8.1% in adult-exposed fish); (iii) higher prevalence of mixed hepato-biliary carcinomas in adult-exposed medaka (24.3%) compared with those exposed as larvae (3%). In addition, a unique hepatocellular lesion termed 'nodular proliferation' was only observed in adult-exposed medaka. The lesion was characterized by small size (50-300 microm), complete loss of normal tubular architecture and variable megalocytosis. Nodular proliferation was distinct from preneoplastic foci of cellular alteration and may represent microcarcinomas. There was a step-wise increase in mean diameter with age (days post-exposure) from nodular proliferation (174 microm, 17 days) to hepatocellular carcinoma (1856 microm, 62 days) and mixed carcinomas (3209 microm, 93 days) in adult-exposed medaka. Metastasis was observed with 19 neoplasms and tumors with the highest metastatic potential were hepatocellular and mixed carcinomas. The most common form of metastasis was trans-coelomic, followed by direct invasion and distant metastasis, presumably via the vascular route. Differences in tumor prevalence between exposure groups were believed to be the result of length of DEN exposure rather than age of fish at the time of exposure. In larval medaka with brief (48 h) DEN exposure, neoplasms are thought to be the result of dedifferentiation of hepatic cells, with slow progression of foci of cellular alteration to benign and then malignant tumors. In contrast, with adult medaka and prolonged (5 week) DEN exposure, neoplasms are believed to result from initiation of committed stem cells and formation of microcarcinomas ('nodular proliferation'), before progressing to larger hepatocellular and then mixed carcinomas.
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PMID:Progression of hepatic neoplasia in medaka (Oryzias latipes) exposed to diethylnitrosamine. 1035 70