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

Since vitamin E increases the antioxidant status of cells, its influence on cytotoxicity was investigated. The neutral red uptake (NRU) inhibition effects of 39 MEIC reference chemicals were measured after treatment of rat hepatoma-derived Fa32 cells in the presence of vitamin E for 30 minutes. The results were quantified in terms of the NI50, the concentration of test compound required to reduce the NRU by 50%. Sodium chloride was the only chemical that was more toxic in the presence of vitamin E. This effect was related to the concentration of vitamin E in the cell culture medium. A vitamin E dose-related response was also observed for the decreased toxicity of paracetamol and caffeine. Glutathione levels were slightly increased in the presence of vitamin E, which could contribute to the protective effect of vitamin E. Of the remaining chemicals, 50% were less toxic in the presence of vitamin E, but the correlation with the acute human toxicity data of the MEIC study was not improved. The results imply that reactive oxygen species interfere with the toxicity of a high proportion of toxic chemicals. The assay described provides a quick and easy method for checking whether reactive oxygen species contribute to the toxicity of a chemical.
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PMID:Cytotoxicity of the MEIC reference chemicals in antioxidant-enriched, rat hepatoma-derived Fa32 cells. 1138 18

Either G-2964 or A734 in the human CYP1A2 gene was confirmed to be associated with high inducible enzyme activity in smokers, but not in nonsmokers. In this study, for the first time, we observed an association between phenotypes and genotypes of CYP1A2 with respect to the two genetic polymorphisms in 163 healthy Chinese volunteers living in Qidong. The ratio of plasma 17X/137X at 6 h after oral administration of 300 mg caffeine was employed in CYP1A2 phenotyping analysis, while genotyping analysis was carried out by polymerase chain reaction-restriction fragment length polymorphism. The allele frequencies of A at -2964 and A at 734 in 139 non-smoking subjects were 0.25 and 0.67, respectively. The A/A-2964C/C734, G/A-2964C/C734 or A/A-2964C/A734 genotype that was thought to have lower inducibility/activity of CYP1A2 than the other genotypes did not exist in the tested Chinese subjects. The ratio of 17X/137X was 0.46 +/- 0.26 in G/G-2964A/A734 genotypes (n = 22) and 0.36 +/- 0.19 in non-G/G-2964A/A734 (n = 117). In addition, there was significant difference between them (P = 0.036). A similar result was also achieved in 24 smokers. Since Qidong is a special region with particularly high incidence of hepatocellular carcinoma in China, the association of phenotypes with genotypes of CYP1A2 in the Qidong population might result from some inducible environmental factors such as those of cigarettes in smokers.
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PMID:Plasma caffeine metabolite ratio (17X/137X) in vivo associated with G-2964A and C734A polymorphisms of human CYP1A2. 1147 Sep 95

We have isolated and characterized an isoform of protein kinase Chk1 gene from rat liver and a rat liver cDNA library by 5'-rapid amplification of cDNA ends. The gene (Cil) contains the C-terminal region of the Chk1 gene, but the 5'-end is derived from a sequence in the intron of Chk1 preceding the C-terminal domain by differential RNA splicing. The kinase domain of Chk1 gene is absent in this isoform. Tissue RNA and protein blot analyses indicated that Cil was specifically expressed only in rat liver, and its expression increased with liver development. Expression of Cil was found to be reduced in three rat hepatoma cell lines examined. A promoter trap experiment suggested that a promoter was located in the intron preceding the C-terminal domain of Chk1, and transcription from this novel promoter generated the new 5' noncoding exon of Cil. Thus Cil was generated by both alternate promoter usage and differential RNA splicing. UV irradiation induced caffeine-sensitive phosphorylation of both Chk1 and Cil at Ser-345 in Chk1 and its equivalent site in Cil, implying a role for ATR kinase in the phosphorylation of both proteins. We demonstrated the interaction between the kinase domain of Chk1 and Cil using a yeast two-hybrid assay and pull-down technique. In contrast to the effect of Chk1, Cil was found to decrease the transactivating function of p53, and the S63A mutation of Cil abolished this effect. These results suggest that Cil may serve as a dominant negative competitor of Chk1 as suggested previously.
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PMID:Cloning and characterization of liver-specific isoform of Chk1 gene from rat. 1168 78

Theophylline is an alkaloid found in tea (Thea sinensis) and chocolate and is structurally related to caffeine and theobromine. Theophylline is used as a pharmaceutical agent. It stimulates the heart and central nervous system, relaxes the smooth muscles of the bronchi and blood vessels, and causes diuresis. The drug is used mainly as a bronchodilator in obstructive airway diseases, such as bronchial asthma, and for myocardial stimulation. Theophylline was nominated for toxicologic and carcinogenicity testing as a representative of the purine structural subclass, particularly because of its relationship to purines such as caffeine, 1-methyl-3-hydroxyguanine, and 3-hydroxy-1-methylxanthine, the latter two compounds having been shown to induce sarcomas in rats. Additional reasons for testing theophylline included its widespread use in humans as a pharmaceutical agent, its possible genotoxicity in vitro, and the lack of information on its potential toxicity and/or carcinogenicity under conditions of chronic oral usage. Based on reported teratogenicity and testicular toxicity, it was also recommended that reproductive studies be included in the evaluation of theophylline. The oral route of administration was selected because it is the primary route of human exposure, and the gavage route was selected because it mimics the pharmaceutical use of theophylline in humans. Male and female F344/N rats and B6C3F1 mice were given theophylline (greater than 99% pure) in feed or in corn oil by gavage for 16 days or 14 weeks or in corn oil by gavage for 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, mouse bone marrow, and mouse peripheral blood. 16-DAY FEED STUDY IN RATS: Groups of five male and five female F344/N rats were given 0, 500, 1,000, 2,000, 4,000, or 8,000 ppm theophylline in feed for 16 days, which resulted in approximate daily doses of 50, 100, 250, 450, or 1,000 mg theophylline/kg body weight to males and 75, 150, 250, 450, or 1,100 mg/kg to females. All rats survived until the end of the study. The final mean body weights and body weight gains of 8,000 ppm males and females were significantly less than those of the controls. The absolute and relative testis weights of 4,000 ppm males were significantly greater than those of the controls. Increased incidences of uterine hypoplasia were observed microscopically in exposed groups of females. 16-DAY GAVAGE STUDY IN RATS: Groups of five male and five female F344/N rats were given 0, 12.5 (twice daily), 25 (once daily), 50 (once daily), 50 (twice daily), 100 (once daily), 200 (once daily), 200 (twice daily), or 400 (once daily) mg theophylline/kg body weight in corn oil by gavage. All rats receiving 400 mg/kg once daily and all but one female receiving 200 mg/kg twice daily died during the study. In groups dosed once daily, final mean body weights and body weight gains of males receiving 100 or 200 mg/kg and mean body weight gains of females receiving 50, 100, or 200 mg/kg were less than those of controls. The final mean body weights and body weight gains of groups receiving theophylline twice daily were generally similar to those of groups receiving the same daily dosages once daily. Clinical findings included rapid or labored respiration, hunched posture, and squinting. In groups dosed once daily, absolute and relative uterus weights of females receiving 100 or 200 mg/kg once daily were significantly less than those of the controls, and the absolute and relative uterus weights of females receiving 100 mg/kg once daily were significantly less than those of females receiving 50 mg/kg twice daily. Uterine atrophy was observed in three females receiving 200 mg/kg twice daily. Periarteritis of the mesenteric arteries was observed in two males and two females receiving 400 mg/kg once daily. 16-DAY FEED STUDY IN MICE: Groups of five male and five female B6C3F1 mice were given 0, 500, 1,000, 2,000, 4,000, or 8,000 ppm theophylline in feed for 16 days, resulting in approximate daily doses of 250, 475, 950, 1,800, or800, or 2,000 mg theophylline/kg body weight to males and 300, 450, 1,225, 2,000, or 4,375 mg/kg to females. All mice survived until the end of the study. Final mean body weights of 4,000 and 8,000 ppm females and mean body weight gains of 2,000, 4,000, and 8,000 ppm females were significantly greater than those of the controls. Feed consumption by exposed groups was similar to that by the controls, except that by the 8,000 ppm males, which was approximately 40% the amount of feed consumed by the control group. Histopathologic examinations were not performed due to the absence of mortality and significant exposure-related lesions. 16-DAY GAVAGE STUDY IN MICE: Groups of five male and five female B6C3F1 mice were given 0, 12.5 (twice daily), 25 (once daily), 50 (once daily), 50 (twice daily), 100 (once daily), 200 (once daily), 200 (twice daily), or 400 (once daily) mg theophylline/kg body weight in corn oil by gavage. Three males and all females receiving 400 mg/kg once daily died on day 1. There were no significant differences in final mean body weights or body weight gains. There were no histopathologic findings attributed directly to theophylline. 14-WEEK FEED STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were given 0, 1,000, 2,000, or 4,000 ppm theophylline in feed for 14 weeks, which resulted in approximate daily doses of 75, 125, or 250 mg theophylline/kg body weight to males and 75, 125, or 275 mg/kg to females. The final mean body weight of 1,000 ppm females was significantly greater than that of the control group. Feed consumption by exposed groups was similar to that by the controls. Mean cell volume and mean cell hemoglobin were significantly greater in males exposed to 2,000 or 4,000 ppm than those in the control group. Segmented neutrophil counts of all groups of exposed females were significantly greater than that of the control group. The absolute and relative kidney weights of 4,000 ppm males were significantly greater than those of the controls, and there was an exposure-related increase in the severity of nephropathy in males. Exposure-related increases in the incidences of mesenteric and/or pancreatic periarteritis were observed in males and females. 14-WEEK GAVAGE STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were given 0, 37.5, 75, or 150 mg theophylline/kg body weight in corn oil by gavage for 14 weeks. One male and one female receiving 150 mg/kg died before the end of the study. The mean body weight gain of 150 mg/kg females was significantly greater than that of the controls. Mean cell volume of 150 mg/kg males and mean cell hemoglobin of all groups of dosed males were significantly greater than those of the control group. There were slight dose-dependent increases in the incidences of mesenteric periarteritis in dosed males and females. 14-WEEK FEED STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were given 0, 1,000, 2,000, or 4,000 ppm theophylline in feed for 14 weeks, resulting in approximate daily doses of 175, 400, or 800 mg theophylline/kg body weight to males and 225, 425, or 850 mg/kg to females. All mice survived until the end of the study. The final mean body weights and body weight gains of all exposed groups of males and females were significantly less than those of the controls. Feed consumption by exposed groups was similar to that by the controls. Leukocyte, segmented neutrophil, and lymphocyte counts of 4,000 ppm males were significantly greater than those of the controls. Leukocyte and segmented neutrophil counts of 2,000 or 4,000 ppm females were significantly greater than those of the controls. There were no histopathologic findings attributed directly to theophylline exposure. 14-WEEK GAVAGE STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were given 0, 75, 150, or 300 mg theophylline/kg body weight in corn oil by gavage for 14 weeks. Three males and all females receiving 300 mg/kg, one 75 mg/kg male, and one control female died before the end of the study. Final mean body weights and body weight gains of 150 and 300 mg/kg males were significantly less than those of the controls. Mean cell volume and mean cell hemoglobin of 300 mg/kg males were significantly greater than those of the controls. There were no histopathologic findings attributed directly to theophylline treatment. 2-YEAR GAVAGE STUDY IN RATS: Groups of 50 male and 50 female rats were given 7.5, 25, or 75 mg theophylline/kg body weight in corn oil by gavage for 2 years. Survival and Body Weights: There were no significant differences in survival between dosed and control groups. Final mean body weights of all groups of dosed males and females were significantly less than those of the controls. Pathology Findings: There were no significantly increased incidences of neoplasms in dosed rats. The incidence of chronic inflammation of the mesenteric arteries was significantly increased in males receiving 75 mg/kg compared to the controls. There were doserelated negative trends in the incidences of mammary gland fibroadenoma and fibroadenoma or carcinoma (combined) in females; these differences correlated with decreased body weights. 2-YEAR GAVAGE STUDY IN MICE: Groups of 50 male B6C3F1 mice were given 0, 15, 50, or 150 mg theophylline/kg body weight and groups of 50 female B6C3F1 mice were given 0, 7.5, 25, or 75 mg/kg in corn oil by gavage for 2 years. Survival and Body Weights: Survival of 150 mg/kg males was significantly less than that of the controls. The final mean body weights of 150 mg/kg males, 25 mg/kg females, and 75 mg/kg females were significantly less than those of the control groups. Pathology Findings: There were no treatment-related increases in incidences of nonneoplastic lesions or neoplasms. In males and females, there were decreased incidences of hepatocellular adenoma and of the combined incidences of hepatocellular adenoma or carcinoma compared to the controls. Male mice had a pattern of nonneoplastic liver lesions along with silver-staining helical organisms in the liver consistent with Helicobacter hepaticus infection. The incidences of these liver lesions in 150 mg/kg males were significantly lower than those in control males. Increases in the incidences of hepatocellular neoplasms in male mice have been shown to be associated with H. hepaticus infection when hepatitis is also present. Because of this association, interpretation of the decreased incidence of liver neoplasms in male mice was more difficult. Incidences of lesions at other sites in this study were not considered to have been significantly impacted by H. hepaticus infection or its associated hepatitis. GENETIC TOXICOLOGY: Theophylline was not mutagenic in Salmonella typhimurium, with or without metabolic activation (S9). It induced sister chromatid exchanges but not chromosomal aberrations in cultured Chinese hamster ovary cells. The positive sister chromatid exchange response was noted only in the absence of S9. In vivo, a mouse bone marrow sister chromatid exchange test showed positive results at a standard 23-hour harvest time; however, this test was not repeated and the response is unconfirmed. An in vivo mouse bone marrow chromosomal aberrations test, that employed both standard and extended exposure protocols, gave negative results. The frequency of micronucleated erythrocytes was determined in peripheral blood of male and female mice exposed to theophylline in dosed feed or in corn oil by gavage for 14 weeks. No significant increases in the frequencies of micronucleated cells were seen in male or female mice in either of the studies. CONCLUSIONS: Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of theophylline in male or female F344/N rats administered 7.5, 25, or 75 mg/kg. There was no evidence of carcinogenic activity of theophylline in male B6C3F1 mice administered 15, 50, or 150 mg/kg or female B6C3F1 mice administered 7.5, 25, or 75 mg/kg. Gavage administration of theophylline caused chronic inflammation of the mesenteric arteries in dosed male rats. Decreased incidences of mammary neoplasms in female rats were likely associated with lower body weights. There were dose-related decreases in the incidences of hepatocellular adenoma and hepatocellular carcinoma in male and female mice. Synonyms: 3,7-dihydro-1,3-dimethyl-1H-purine-2,6-dione; 1,3-dimethylxanthine; 1H-purine-2,6-dione; NSC 2066; pseusdotheophylline; theocin; theophyllin; theophylline, anhydrous Trade names: Accurbron; Aerobin; Aerolate III; Afonilum; Aminophylline; Aquaphyllin; Armophylline; Asmalix; Bilordyl; Bronchoretard; Bronkodyl; Cetraphylline; Constant-T; Diffumal; Duraphyl; Duraphyllin; Elixicon; Elixophyllin; Euphylline L.A.; Euphylong; LaBID; Labophylline; Lanophyllin; Lasma; Liquophylline; Optiphyllin; Parkophyllin; Phylocontin; Physpan; Pro-Vent; PulmiDur; Pulmo-Timelets; Quibron; Respbid; Rona-Phyllin; Sabidal; Slo-bid; Slo-Phyllin; Solosin; Sustaire; Tefamin; Teobid; Teofyllamin; Tesona; Theal tablets; Theo-24; Theobid; Theocap; Theochron; Theoclear; Theocontin; Theo-Dur; Theofol; Theograd; Theolair; Theolan; Theolix; Theophyl; Theoplus; Theo-Sav; Theosol; Theospan; Theostat; Theovent; TheoX; T-Phyl; Truphylline; Uni-Dur; Unifyl; Uniphyl; Uniphyllin; Xanthium
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PMID:NTP Toxicology and Carcinogenesis Studies of Theophylline (CAS No. 58-55-9) in F344/N Rats and B6C3F1 Mice (Feed and Gavage Studies). 1257 77

Trichloroethylene (TCE) is an industrial solvent used for vapor degreasing and cold cleaning of fabricated metal parts. TCE has also been used as a carrier solvent for the active ingredients of insecticides and fungicides, as a solvent for waxes, fats, resins, and oils, as an anesthetic for medical and dental use, and as an extractant for spice oleoresins and for caffeine from coffee. Trichloroethylene may be found in printing inks, varnishes, adhesives, paints, lacquers, spot removers, rug cleaners, disinfectants, and cosmetic cleansing fluids. TCE may also be used as a chain terminator in polyvinyl chloride production and as an intermediate in the production of pentachloroethane. Trichloroethylene is no longer used with food, drugs, or cosmetics. NTP Carcinogenesis studies of epichlorohydrin-free trichloroethylene were conducted by administering the test chemical in corn oil by gavage to groups of 50 male and 50 female F344/N rats and B6C3F1 mice. Dosage levels were 500 and 1,000 mg/kg for rats and 1,000 mg/kg for mice. Trichloroethylene was administered five times per week for 103 weeks, and surviving animals were killed between weeks 103 and 107. Groups of 50 rats and 50 mice of each sex received corn oil by gavage on the same schedule and served as vehicle controls. Groups of 50 male and 50 female rats were used as untreated controls. The dosage levels selected for the 2-year study were based on the results of the 13-week studies. Groups of 10 male and 10 female rats received TCE by gavage at doses of 125 to 2,000 mg/kg (males) and 62.5 to 1,000 mg/kg (females) for 13 weeks. Groups of 10 male and 10 female mice received gavage doses of 375 to 6,000 mg/kg of TCE for 13 weeks. Survival, body weight gains, and previous experience with TCE were used to select doses for the 2-year study. All rats survived the 13-week study, but males receiving 2,000 mg/kg exhibited a 24% difference in final body weight. At the 1,000 mg/kg dose, final body weights for males (-3%) and for females (-2%) were similar to those of controls. The doses selected for the 2-year study in rats were 500 and 1,000 mg/kg for both sexes. The initial doses used in the earlier bioassay in Osborne-Mendel rats were 549 and 1,097 mg/kg for both sexes. A total of 8/10 male mice and 10/10 female mice receiving doses of TCE as high as 1,500 mg/kg survived the 13-week experimental period. The single dosage level selected for the 2-year study in mice was 1,000 mg/kg for both sexes. This dose was less than the high dose used in the earlier bioassay in B6C3F1 mice (2,339 mg/kg for males and 1,739 for females) and was similar to the previous low doses (1,169 mg/kg for males and 869 for females). In the 2-year study, the survival of both low and high dose male rats and dosed male mice was less (P</=0.005) than that of the vehicle controls. Mean body weights of dosed rats of each sex were lower than those of the vehicle controls, and after week 65, the decrements in body weight gains were dose related. The mean body weight of dosed male mice was lower than that of the vehicle controls throughout the study, while those of the dosed and vehicle control female mice were comparable. Cytomegaly (toxic nephrosis) of the kidney was observed in 96/98 male and in 97/97 female rats given TCE, with none being found in male or female vehicle control rats. This lesion was more severe in males, particularly in the high dose group. Cytomegaly was observed in 45/50 male mice and in 48/49 female mice administered TCE, and in none of the vehicle controls. Renal tubular cell adenocarcinomas were found in the three high dose male rats; these neoplasms were observed in those male rats killed at the end of the study (0/33, 0/20, and 3/16, 19%). The incidence in the high dose male rats at the end of the study was greater (P<0.05) than that in the controls. Renal tubular cell adenocarcinomas are considered uncommon occurrences in F344/N rats, with 3/748 (0.4%) being observed in historical vehicle gavage controls. Additional renal tumors in dosed male rats included one transitional cell carcats included one transitional cell carcinoma of the renal pelvis and two tubular cell adenomas in low dose animals and one carcinoma of the renal pelvis in a high dose animal. No renal neoplasms were found in vehicle control rats; one untreated control male rat had a transitional cell papilloma of the renal pelvis. In female rats, one tubular cell adenocarcinoma was found in the high dose group. An increased incidence (P&lt;0.05, life table) of peritoneal mesotheliomas was detected in low dose male rats (control, 1/50; low dose, 5/50; high dose, 1/49). Mesotheliomas have been diagnosed in 16/752 (2.1&percnt;) historical vehicle control male F344/N rats, and the increased incidence in the present study may have been related to the administration of TCE. The results in male F344/N rats were considered equivocal for detecting a carcinogenic response because both groups receiving TCE showed significantly reduced survival compared to vehicle controls (35/50, 70&percnt;, 20/50, 40&percnt;; 16/50, 32&percnt;) and because 20&percnt; of the animals in the high dose group were killed accidently by gavage error. Negative trends were observed for chromophobe adenomas of the pituitary gland and for endometrial stomal polyps in female rats. These decreases were not considered to be related to the administration of TCE. The administration of TCE to mice caused increased incidences of hepatocellular carcinoma in males (control, 8/48; dosed, 31/50; P&lt;0.001) and in females (control, 2/48; dosed, 13/49; P&lt;0.005). Hepatocellular carcinomas metastasized to the lungs in five dosed male mice and one control male mouse, and none were observed in females. The incidence of hepatocellular adenomas was increased in male mice (control, 7/48; dosed 14/50) and in female mice (control, 4/48; dosed, 16/49; P&lt;0.05). Under the conditions of these studies, epichlorohydrin-free trichloroethylene caused renal tubular-cell neoplasms in male F344/N rats, produced toxic nephrosis in both sexes, and shortened the survival time of males. This experiment in male F344/N rats was considered to be inadequate to evaluate the presence or absence of a carcinogenic response to trichloroethylene. For female F344/N rats receiving trichloroethylene, containing no epichlorohydrin, there was no evidence of carcinogenicity. Trichloroethylene (without epichlorohydrin) was carcinogenic for B6C3F1 mice, causing increased incidences of hepatocellular carcinomas in males and females and of hepatocellular adenomas in females. Levels of Evidence of Carcinogenicity: Male Rats: Inadequate Study Female Rats: Negative Male Mice: Positive Female Mice: Positive Synonym: TCE
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PMID:NTP Carcinogenesis Studies of Trichloroethylene (Without Epichlorohydrin) (CAS No. 79-01-6) in F344/N Rats and B6C3F1 Mice (Gavage Studies). 1275 Jul 50

Genistein, biochanin-A, and daidzein, the predominant soy isoflavones, have been reported to lower the risk of cancer, but it is not known whether they protect against human hepatoma cancer. This study was designed to investigate their effects on cell growth, the cell cycle, and apoptosis induction in the human hepatoma cell lines, HepG2, Hep3B, Huh7, PLC, and HA22T. Genistein, biochanin-A, and daidzein inhibited growth of all five lines in a dose-dependent manner. DNA fragmentation studies and the TUNEL assay demonstrated that isoflavones caused tumor cell death by induction of apoptosis. Activation of caspase-3 and cleavage of the caspase-3 substrate, poly(ADP-ribose)polymerase, was seen in hepatoma cells after 24 hours' exposure to isoflavones. In addition, isoflavone cytotoxicity correlated with downregulation of Bcl-2 and Bcl-XL expression. Synergistic effects of the three isoflavones were observed on cell growth inhibition, apoptosis induction, and anti-apoptotic protein expression. Flow cytometry showed that genistein, but not biochanin-A or daidzein, induced progressive and sustained accumulation of hepatoma cancer cells in the G2/M phase as a result of inhibition of Cdc2 kinase activity. Coapplication of caffeine prevented this cell cycle arrest, but not apoptosis, showing that cell cycle arrest was not necessary for apoptosis. Furthermore, the isoflavones combination also had a significant tumor-suppressive effect in nude mice. These results suggest that isoflavones might be promising agents for the treatment of human hepatoma.
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PMID:Effects of soy isoflavones on apoptosis induction and G2-M arrest in human hepatoma cells involvement of caspase-3 activation, Bcl-2 and Bcl-XL downregulation, and Cdc2 kinase activity. 1279 11

CYP1A2 polymorphism has been well studied in white persons and Asians but not in Africans. We performed CYP1A2 genotype and phenotype analysis using caffeine in Ethiopians living in Ethiopia (n = 100) or in Sweden (n = 73). We sequenced the CYP1A2 gene using genomic DNA from 12 subjects, which revealed a novel intron 1 single-nucleotide polymorphism (SNP), -730C>T. We developed SNP-specific polymerase chain reaction-restriction fragment length polymorphism genotyping and molecular haplotyping methods for the intron 1 SNPs, and four different haplotypes were identified: CYP1A2*1A (wild-type for all SNPs), CYP1A2*1F (-164A), CYP1A2*1J (-740G and -164A), and CYP1A2*1K (-730T, -740G, and -164A), having frequencies of 39.9, 49.6, 7.5, and 3.0%, respectively. The frequency of CYP1A2*1J and CYP1A2*1K among Saudi Arabians (n = 136) was 5.9% and 3.6%, and among Spaniards (n = 117) 1.3% and 0.5%, respectively. Functional significance of the different intron 1 haplotypes was analyzed. Subjects with CYP1A2*1K had significantly decreased CYP1A2 activity in vivo, and reporter constructs with this haplotype had significantly less inducibility with 2,3,7,8-tetrachlorodibenzo-p-dioxin in human B16A2 hepatoma cells. Electrophoretic mobility shift assay using nuclear extracts from B16A2 cells revealed a specific DNA binding protein complex to an Ets element. Efficient competition was obtained using oligonucleotide probes carrying the wt sequence and Ets consensus probe, whereas competition was abolished using probes with the -730C>T SNP alone or in combination with -740T>G (CYP1A2*1K). The results indicate a novel polymorphism in intron 1 of importance for Ets-dependent CYP1A2 expression in vivo and inducibility of the enzyme, which might be of critical importance for determination of interindividual differences in drug metabolism and sensitivity to carcinogens activated by CYP1A2.
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PMID:Genetic polymorphism of CYP1A2 in Ethiopians affecting induction and expression: characterization of novel haplotypes with single-nucleotide polymorphisms in intron 1. 1292 Feb 2

Genistein, a soy isoflavone, has a wide range of biological actions that suggest it may be of use in cancer prevention. We have recently reported that it arrests hepatoma cells at G2/M phase and inhibits Cdc2 kinase activity. In the present study, we examined the signaling pathway by which genistein modulates Cdc2 kinase activity in HepG2 cells and leads to G2/M arrest, and found that it caused an increase in both Cdc2 phosphorylation and expression of the Cdc2-active kinase, Wee1. Genistein also enhanced the expression of the cell cycle inhibitor, p21waf1/cip1, which interacts with Cdc2. Furthermore, phosphorylation/inactivation of Cdc25C phosphatase, which dephosphorylates/activates Cdc2, was increased. Genistein enhanced the activity of the checkpoint kinase, Chk2, which phosphorylates/inactivates Cdc25C, induced accumulation of p53, and activated the ataxia-telangiectasia-mutated (ATM) gene. Caffeine, an ATM kinase inhibitor, inhibited these effects of genistein on Chk2, p53, and p21waf1/cip1. These findings suggest that the effect of genistein on G2/M arrest in HepG2 cells is partly due to ATM-dependent Chk2 activation, an increase in Cdc2 phosphorylation/inactivation as a result of induction of Wee1 expression, and a decrease in Cdc2 activity as a result of induction of p21waf1/cip1 expression.
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PMID:Genistein arrests hepatoma cells at G2/M phase: involvement of ATM activation and upregulation of p21waf1/cip1 and Wee1. 1475 71

We present a patient with hepatitis C and D and hepatocellular carcinoma who underwent preoperative evaluation for orthotopic liver transplantation. In his past medical history, he reported a life-threatening event during tonsillectomy in 1975. Intubation was impossible due to extreme jaw muscle tension, followed by excessive elevation in body temperature, tachycardia, and coma for a few days. We evaluated him for malignant hyperthermia, according to the European Malignant Hyperthermia Group Protocol, and found him highly positive in both the halothane and caffeine test, respectively. Three months later, we performed an orthotopic liver transplantation. During retransplantation 4 years later, due to ischemic-type biliary lesions, he suffered massive intraoperative bleeding. Blood products, as well as coagulation factors and aprotinin, were well tolerated. Anesthesia was performed in a trigger-free total intravenous technique without dantrolene prophylaxis, but dantrolene was readily available in sufficient quantities in the operating room. The patient did not encounter a malignant hyperthermia crisis in either perioperative period.
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PMID:Orthotopic liver transplantation in a malignant hyperthermia susceptible patient. 1629 58

Coffee is a complex mixture of chemicals that provides significant amounts of chlorogenic acid and caffeine. Unfiltered coffee is a significant source of cafestol and kahweol, which are diterpenes that have been implicated in the cholesterol-raising effects of coffee. The results of epidemiological research suggest that coffee consumption may help prevent several chronic diseases, including type 2 diabetes mellitus, Parkinson's disease and liver disease (cirrhosis and hepatocellular carcinoma). Most prospective cohort studies have not found coffee consumption to be associated with significantly increased cardiovascular disease risk. However, coffee consumption is associated with increases in several cardiovascular disease risk factors, including blood pressure and plasma homocysteine. At present, there is little evidence that coffee consumption increases the risk of cancer. For adults consuming moderate amounts of coffee (3-4 cups/d providing 300-400 mg/d of caffeine), there is little evidence of health risks and some evidence of health benefits. However, some groups, including people with hypertension, children, adolescents, and the elderly, may be more vulnerable to the adverse effects of caffeine. In addition, currently available evidence suggests that it may be prudent for pregnant women to limit coffee consumption to 3 cups/d providing no more than 300 mg/d of caffeine to exclude any increased probability of spontaneous abortion or impaired fetal growth.
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PMID:Coffee and health: a review of recent human research. 1650 75


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