The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Andrzej Tokarz - One of the best experts on this subject based on the ideXlab platform.
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impact of conjugated linoleic acid administered to rats prior and after Carcinogenic Agent on arachidonic and linoleic acid metabolites in serum and tumors
Prostaglandins Leukotrienes and Essential Fatty Acids, 2017Co-Authors: Malgorzata Jelinska, Agnieszka Bialek, I Gielecinska, Hanna Mojska, Andrzej TokarzAbstract:Abstract The objective of the study was to assess the influence of conjugated linoleic acid (CLA) daily supplementation prior and after Carcinogenic Agent on the concentrations of eicosanoids – metabolites of arachidonic acid (15-, 12- or 5-hydroxyeicosatetraenoic acids (15-, 12-, 5-HETE), prostaglandin E 2 (PGE 2 )) and linoleic acid (13- or 9-hydroxyoctadecadienoic acids (13-, 9-HODE)) in rat serum and 7,12-dimethylbenz[ a ]anthracene (DMBA)-induced tumors. Female rats were randomised into six groups, receiving 1% or 2% Bio-C.L.A or plant oil since the 37th day of life throughout the whole experiment. Some rats (50-day-old) were administered DMBA to induce tumors. Eicosanoids were analyzed with LC-MS/MS. The study indicated that CLA supplemented daily to rats prior and after carcinogen administration affected concentrations of arachidonic and linoleic acid metabolites in rat serum and induced tumors. However, ratios of eicosanoids exerting opposite activities (e.g. 12-HETE/15-HETE) appear to act as more precise factors reflecting pathological changes in an organism than individual compounds.
Malgorzata Jelinska - One of the best experts on this subject based on the ideXlab platform.
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impact of conjugated linoleic acid administered to rats prior and after Carcinogenic Agent on arachidonic and linoleic acid metabolites in serum and tumors
Prostaglandins Leukotrienes and Essential Fatty Acids, 2017Co-Authors: Malgorzata Jelinska, Agnieszka Bialek, I Gielecinska, Hanna Mojska, Andrzej TokarzAbstract:Abstract The objective of the study was to assess the influence of conjugated linoleic acid (CLA) daily supplementation prior and after Carcinogenic Agent on the concentrations of eicosanoids – metabolites of arachidonic acid (15-, 12- or 5-hydroxyeicosatetraenoic acids (15-, 12-, 5-HETE), prostaglandin E 2 (PGE 2 )) and linoleic acid (13- or 9-hydroxyoctadecadienoic acids (13-, 9-HODE)) in rat serum and 7,12-dimethylbenz[ a ]anthracene (DMBA)-induced tumors. Female rats were randomised into six groups, receiving 1% or 2% Bio-C.L.A or plant oil since the 37th day of life throughout the whole experiment. Some rats (50-day-old) were administered DMBA to induce tumors. Eicosanoids were analyzed with LC-MS/MS. The study indicated that CLA supplemented daily to rats prior and after carcinogen administration affected concentrations of arachidonic and linoleic acid metabolites in rat serum and induced tumors. However, ratios of eicosanoids exerting opposite activities (e.g. 12-HETE/15-HETE) appear to act as more precise factors reflecting pathological changes in an organism than individual compounds.
Jack A Taylor - One of the best experts on this subject based on the ideXlab platform.
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mutations in tetranucleotide repeats following dna damage depend on repeat sequence and Carcinogenic Agent
Cancer Research, 2002Co-Authors: Robbert J C Slebos, Daniel S Oh, David M Umbach, Jack A TaylorAbstract:Sporadic microsatellite mutations are frequently observed in lung, bladder, and head and neck tumors with intact DNA mismatch repair. AAAG tetranucleotide repeats appear to be especially prone to the accumulation of these mutations. We hypothesized that occurrences of microsatellite mutations in these cancers may be linked to DNA damage caused by exposure to carcinogens in tobacco smoke. To test this hypothesis, we developed a model system based on reactivation of green fluorescent protein (GFP) in which a plasmid vector carries a microsatellite repeat that places the GFP sequence out of frame for protein translation. In this reporter system, DNA slippage mutations can restore the GFP reading frame and become detectable by flow cytometry as GFP-positive cells. Pools of stably transfected RKO cells were treated at four dose levels each of γ-irradiation, benzo(a)pyrene diol epoxide, N-methyl-N-nitro-N-nitrosoguanidine (MNNG), t-butyl hydrogen peroxide, and UV irradiation and assayed for GFP-positive cells 48 h later. We studied the microsatellite repeats AAAG, ATAG, CAGT, and CA, as well as a control sequence lacking any repetitive elements. A log-linear regression approach was used to discriminate between the effects of repeat unit and dose for each Agent. A statistically significant increase in GFP-positive cells was found with increasing dose with all Agents, although repeat unit-specific response patterns were only observed with MNNG, t-butyl hydrogen peroxide, and UV irradiation. With MNNG, significant differences in response were observed between dinucleotide and tetranucleotide repeat units. The effects of UV irradiation were consistent with the predicted number of pyrimidine dimers/repeat unit, with higher GFP activation in repeats that had large numbers of adjacent pyrimidines. We found no evidence to indicate that the AAAG repeat responded to any of the DNA-damaging Agents with higher levels of GFP activation than other repeat units. These results provide evidence that DNA damage can induce slippage mutations and increase mutation rates in repeated sequences and that there are sequence-specific responses to different types of DNA damage. Our results are compatible with the hypothesis that sporadic microsatellite mutations in human cancer may reflect DNA damage caused by carcinogen exposure.
J Van Sande - One of the best experts on this subject based on the ideXlab platform.
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acrylamide an in vivo thyroid Carcinogenic Agent induces dna damage in rat thyroid cell lines and primary cultures
Molecular and Cellular Endocrinology, 2006Co-Authors: Chico V Galdo, Claude Massart, V Vanvooren, P Cailletfauquet, Guy Andry, Philippe Lothaire, Didier Dequanter, M Friedman, J Van SandeAbstract:Chronic treatment of rats with acrylamide induces various tumors among which thyroid tumors are the most frequent. The aim of the present study was to develop an in vitro model of acrylamide action on thyroid cells to allow the investigation of the mechanism of this tumorigenic action. The first part of the study considered as targets, characteristics of thyroid metabolism, which could explain the thyroid specificity of acrylamide action: the cAMP mitogenic effect and the important H2O2 generation by thyroid cells. However, acrylamide did not modulate H2O2 or cAMP generation in the thyroid cell models studied. No effect on thyroid cell proliferation was observed in the rat thyroid cell line FRTL5. On the other hand, as shown by the comet assay, acrylamide induced DNA damage, as the positive control H2O2 in the PC Cl3 and FRTL5 rat thyroid cell lines, as well as in thyroid cell primary cultures. The absence of effect of acrylamide on H2AX histone phosphorylation suggests that this effect does not reflect the induction of DNA double strand breaks. DNA damage leads to the generation of mutations. It is proposed that such mutations could play a role in the Carcinogenic effect of acrylamide. The mechanism of this effect can now be studied in this in vitro model.
Raafat R. Mansour - One of the best experts on this subject based on the ideXlab platform.
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Miniature Gas Sensor and Sensor Array With Single- and Dual-Mode RF Dielectric Resonators
IEEE Transactions on Microwave Theory and Techniques, 2018Co-Authors: Wei-ting Scott Chen, Raafat R. MansourAbstract:RF resonant polymer-coated sensors are a proven effective approach to enhance the sensitivity of polymeric sensing materials. However, the level of sensitivity improvement offered by an RF resonant sensor is directly proportional to the quality factor (Q) of the resonator-the larger the Q-factor, the higher the sensitivity enhancement is. This paper first presents a miniature polymer-based dielectric resonant (DR) sensor design operated at its fundamental mode (TEH) at 24 GHz demonstrating a measured Q-factor of 3820. The sensor is coated with a (per)nigraniline-based conductive sensing material for detections of acetone and isopropanol volatile organic compounds and has a small footprint of 4.5 mm × 4.5 mm. The sensor has demonstrated a low-ppm detection capability for acetone and isopropanol gases with a response onset time less than 15 s. This paper further demonstrates a novel airborne Carcinogenic Agent sensor array implemented with a single dielectric resonator operating in dual mode (HEH) at 27 GHz. It is functionalized by placing two carcinogen sensing materials-polyhydroxyethylmethacrylate (PHM) and fluoroalcohol polysiloxanes (FAPS)- at the optimal geometrical locations on the DR, such that the polymers would independently affect the resonant frequencies of the two orthogonal HEH degenerate modes. By monitoring Δf0 and ΔS11 near f0,HEH1 and f0,HEH2, both the concentrations and the response signatures of the airborne Carcinogenic Agents can be detected. The measurement results indicate that the HEH-mode two-sensor array carrying PHM and FAPS is successful in identifying and differentiating two Carcinogenic Agents- dioxane and benzene-and their respective concentrations.