PubMed · 14241138
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
D D EVANS, D E EVANS, G S LEWIS, P J PALMER, D J WEYELL. 1964. GENOTROPIC AGENTS: STEROID BASIC ETHERS.. https://doi.org/10.1111/j.2042-7158.1964.tb07395.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
In addition to the loss of function, mutant p53 can possess a dominant-negative effect on wild-type p53 and may also exert gain-of-function activity. It is not clear whether the functional status of p53 mutation contributes to differences in outcome in endometrial cancer. We collected a total of 92 RNA samples of high quality from endometrial cancer tissues, and the samples were subjected to yeast functional assay and sequencing for p53 mutations. The detected mutant p53 genes were further investigated for their dominant-negative activity using a yeast-based transdominance assay. p53 mutation was found in 24 out of 92 (26.1%) tumors, of which 10 exhibited no dominant-negative activity (recessive mutation) and 14 showed dominant-negative activity. Dominant-negative p53 mutation was related to advanced stages (p = 0.01), nonendometrioid type tumors (p = 0.01) and grade 3 tumors (p = 0.04). The patients with dominant-negative mutation had significantly shorter survival than patients with no mutation (p < 0.0001) and those with a recessive mutation (p = 0.01) in the p53 gene. No difference in survival was found between the patients with tumors harboring a recessive p53 mutation and those with tumors harboring a wild-type p53. Multivariate analysis revealed that dominant-negative p53 mutation (p = 0.019), FIGO stage (p = 0.0037) and histologic subtype (p = 0.014) were independently related to patient survival. Dominant-negative p53 mutation was the most important prognostic factor for stage III/IV endometrial cancer (p = 0.0023). In conclusion, dominant-negative p53 mutation is often found in advanced stages and aggressive histologic subtypes of endometrial cancer and it is a strong predictor of survival of patients with advanced endometrial cancer. To elucidate further the role of p53 mutation in endometrial cancer, it is necessary to investigate gain-of-function activity involving dominant-negative p53 mutant proteins.
Electrochemical microbial chip for mutagen screening were microfabricated and characterized by scanning electrochemical microscopy (SECM). Salmonella typhimurium TA1535 with a plasmid pSK1002 carrying a umuC'-'lacZ fusion gene was used for the whole cell mutagen sensor. The TA1535/pSK1002 cells were exposed to mutagen solutions containing 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamido (AF-2), mitomycin C (MMC) or 2-aminoanthracene (2-AA) and embedded in a microcavity (5nl) on a glass substrate using collagen gel. The beta-galactosidase expression on the microbial chip was electrochemically monitored using p-aminophenyl-beta-d-galactopyranoside (PAPG) as the enzymatic substrate. This system has several advantages compared with the conventional umu test: drastic reduction of the sample volume, less time-consuming for beta-galactosidase detection (free from substrate reaction time) and lower detection limit for the three mutagens (AF-2, MMC, 2-AA). Finally, a multi-sample assay was carried out using the microbial array chip with four microcavities.
The microsomal stability assay is commonly used to rank compounds according to their metabolic stability. Determination of the unbound intrinsic clearance (CL(in,u)) is essential for the accurate comparison of compounds, since nonspecific binding to microsomes can lead to an underestimation of the microsomal clearance. In this study, a new method (linear extrapolation in the stability assay, LESA) was established, which allows direct calculation of CL(in,u) from microsomal stability data, without the need to independently determine the fraction of free (unbound) drug. The method was validated using nine drugs with different chemical structures and physicochemical properties. The CL(in,u) of these compounds was extrapolated from the intrinsic clearance values obtained at different concentrations of human liver microsomes and compared with that calculated by the conventional method, using microsomal intrinsic clearance values and the free fraction of drug determined by equilibrium dialysis, ultracentrifugation, or ultrafiltration. A good agreement was observed between the data generated by the LESA method and those determined by conventional procedures. The method was further evaluated using a published dataset for 10 additional drugs and found to yield intrinsic clearance data comparable to the previously reported values. LESA provides a convenient and rapid method to determine the influence of microsome binding on intrinsic clearance in a single assay.