The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Y.x. Lei - One of the best experts on this subject based on the ideXlab platform.
-
effects of metabolites of benzo a pyrene on unschedule dna synthesis in balb 3T3 Cell Line
Chemosphere, 2000Co-Authors: Jianfei Chen, Y.g. Liu, Y.x. LeiAbstract:In order to explore the damage from metabolites of benzo(a)pyrene on DNA of mammalian Cells, the effects of four metabolites of benzo(a)pyrene (anti-BPDE, syn-BPDE, 3-OH-BP and 9-OH-BP) on synthesis of DNA and unschedule DNA synthesis (UDS) in BALB/3T3 Cells were assayed, by methods of single-labeling and double-labeling. The results showed that all of the four agents were able to increase the synthesis of DNA, but only three of them (apart from syn-BPDE) induced UDS in BALB/3T3 Cells. The above indicates that the metabolites of benzo(a)pyrene are able to damage DNA in BALB/3T3 Cells, and that this effect may be relative to the sterical structure of metabolites of benzo(a)pyrene.
-
Effects of metabolites of benzo(a)pyrene on unschedule DNA synthesis in BALB/3T3 Cell Line.
Chemosphere, 2000Co-Authors: Jianfei Chen, Y.g. Liu, Y.x. LeiAbstract:In order to explore the damage from metabolites of benzo(a)pyrene on DNA of mammalian Cells, the effects of four metabolites of benzo(a)pyrene (anti-BPDE, syn-BPDE, 3-OH-BP and 9-OH-BP) on synthesis of DNA and unschedule DNA synthesis (UDS) in BALB/3T3 Cells were assayed, by methods of single-labeling and double-labeling. The results showed that all of the four agents were able to increase the synthesis of DNA, but only three of them (apart from syn-BPDE) induced UDS in BALB/3T3 Cells. The above indicates that the metabolites of benzo(a)pyrene are able to damage DNA in BALB/3T3 Cells, and that this effect may be relative to the sterical structure of metabolites of benzo(a)pyrene.
Els M. De Groene - One of the best experts on this subject based on the ideXlab platform.
-
Tiamulin inhibits human CYP3A4 activity in an NIH/3T3 Cell Line stably expressing CYP3A4 cDNA
Biochemical pharmacology, 1995Co-Authors: Els M. De Groene, S. M. Nijmeijer, G.jean Horbach, Renger F. WitkampAbstract:Tiamulin is an antibiotic frequently used in veterinary medicine. The drug has been shown to produce clinically important interactions with other compounds that are administered simultaneously. An NIH/3T3 Cell Line, stably expressing human cytochrome P450 (EC 1.14.14.1) cDNA (CYP3A4), was used to study the effect of tiamulin on CYP3A4 activity. The 6 beta-hydroxylation activity of testosterone, which is increased in CYP3A4-expressing Cells compared to vector-transfected Cells, showed reduced activity after incubation with 1 microM tiamulin and was completely reduced to background level after incubation with 2, 5 and 10 microM tiamulin. The CYP3A4-expressing Cell Line was used in combination with a shuttle vector containing the bacterial lacZ' gene to study the effect of tiamulin on CYP3A4-mediated mutagenicity of aflatoxin B1. The mutation frequency of aflatoxin B1 could be completely inhibited by tiamulin in CYP3A4-expressing Cells, but no effect was observed on the mutation frequency of the direct mutagen ethylmethanesulphonate. Western blotting of homogenates of the CYP3A4-expressing Cell Line showed stabilization of CYP3A4 protein after incubation with tiamulin, supporting the hypothesis that the mechanism of inhibition is by binding of tiamulin to the cytochrome.
-
tiamulin inhibits human cyp3a4 activity in an nih 3T3 Cell Line stably expressing cyp3a4 cdna
Biochemical Pharmacology, 1995Co-Authors: Els M. De Groene, S. M. Nijmeijer, Jean G Horbach, Renger F. WitkampAbstract:Tiamulin is an antibiotic frequently used in veterinary medicine. The drug has been shown to produce clinically important interactions with other compounds that are administered simultaneously. An NIH/3T3 Cell Line, stably expressing human cytochrome P450 (EC 1.14.14.1) cDNA (CYP3A4), was used to study the effect of tiamulin on CYP3A4 activity. The 6 beta-hydroxylation activity of testosterone, which is increased in CYP3A4-expressing Cells compared to vector-transfected Cells, showed reduced activity after incubation with 1 microM tiamulin and was completely reduced to background level after incubation with 2, 5 and 10 microM tiamulin. The CYP3A4-expressing Cell Line was used in combination with a shuttle vector containing the bacterial lacZ' gene to study the effect of tiamulin on CYP3A4-mediated mutagenicity of aflatoxin B1. The mutation frequency of aflatoxin B1 could be completely inhibited by tiamulin in CYP3A4-expressing Cells, but no effect was observed on the mutation frequency of the direct mutagen ethylmethanesulphonate. Western blotting of homogenates of the CYP3A4-expressing Cell Line showed stabilization of CYP3A4 protein after incubation with tiamulin, supporting the hypothesis that the mechanism of inhibition is by binding of tiamulin to the cytochrome.
-
A NIH/3T3 Cell Line stably expressing human cytochrome P450-3A4 used in combination with a lacZ′ shuttle vector to study mutagenicity
European journal of pharmacology, 1995Co-Authors: Els M. De Groene, Willem Seinen, G.jean HorbachAbstract:Abstract An NIH/3T3 Cell Line, stably expressing human cytochrome P450-3A4 (CYP3A4) cDNA has been developed. This Cell Line was used in combination with a shuttle vector, containing the bacterial lacZ′ gene as reporter gene, to study mutagenicity. Ethylmethanesulphonate and aflatoxin B 1 were used as model agents to test this system. The mutation frequency of ethylmethanesulphonate increased concentration dependently and was the same in CYP3A4-expressing Cells as in parental NIH/3T3 Cells, demonstrating that CYP3A4 activity has no influence on the mutagenicity of ethylmethanesulphonate. The mutation frequency of aflatoxin B 1 increased concentration dependently only in the CYP3A4-expressing Cells and not in parental nor in vector-transfected Cells. This increase in mutation frequency could be completely inhibited by ketoconazole, an inhibitor of cytochrome P450 activity, demonstrating the role of CYP3A4 in the activation of aflatoxin B 1 . The system described in this paper opens the possibility to study the capacity of single human cytochrome P450s to activate xenobiotics into mutagenic metabolites. Since activation, phase II metabolism, DNA repair and an endpoint for mutations are all present in one Cell, this system will be useful in screening as well as in mechanistic studies.
-
a nih 3T3 Cell Line stably expressing human cytochrome p450 3a4 used in combination with a lacz shuttle vector to study mutagenicity
European Journal of Pharmacology: Environmental Toxicology and Pharmacology, 1995Co-Authors: Els M. De Groene, Willem Seinen, Jean G HorbachAbstract:Abstract An NIH/3T3 Cell Line, stably expressing human cytochrome P450-3A4 (CYP3A4) cDNA has been developed. This Cell Line was used in combination with a shuttle vector, containing the bacterial lacZ′ gene as reporter gene, to study mutagenicity. Ethylmethanesulphonate and aflatoxin B 1 were used as model agents to test this system. The mutation frequency of ethylmethanesulphonate increased concentration dependently and was the same in CYP3A4-expressing Cells as in parental NIH/3T3 Cells, demonstrating that CYP3A4 activity has no influence on the mutagenicity of ethylmethanesulphonate. The mutation frequency of aflatoxin B 1 increased concentration dependently only in the CYP3A4-expressing Cells and not in parental nor in vector-transfected Cells. This increase in mutation frequency could be completely inhibited by ketoconazole, an inhibitor of cytochrome P450 activity, demonstrating the role of CYP3A4 in the activation of aflatoxin B 1 . The system described in this paper opens the possibility to study the capacity of single human cytochrome P450s to activate xenobiotics into mutagenic metabolites. Since activation, phase II metabolism, DNA repair and an endpoint for mutations are all present in one Cell, this system will be useful in screening as well as in mechanistic studies.
Jianfei Chen - One of the best experts on this subject based on the ideXlab platform.
-
effects of metabolites of benzo a pyrene on unschedule dna synthesis in balb 3T3 Cell Line
Chemosphere, 2000Co-Authors: Jianfei Chen, Y.g. Liu, Y.x. LeiAbstract:In order to explore the damage from metabolites of benzo(a)pyrene on DNA of mammalian Cells, the effects of four metabolites of benzo(a)pyrene (anti-BPDE, syn-BPDE, 3-OH-BP and 9-OH-BP) on synthesis of DNA and unschedule DNA synthesis (UDS) in BALB/3T3 Cells were assayed, by methods of single-labeling and double-labeling. The results showed that all of the four agents were able to increase the synthesis of DNA, but only three of them (apart from syn-BPDE) induced UDS in BALB/3T3 Cells. The above indicates that the metabolites of benzo(a)pyrene are able to damage DNA in BALB/3T3 Cells, and that this effect may be relative to the sterical structure of metabolites of benzo(a)pyrene.
-
Effects of metabolites of benzo(a)pyrene on unschedule DNA synthesis in BALB/3T3 Cell Line.
Chemosphere, 2000Co-Authors: Jianfei Chen, Y.g. Liu, Y.x. LeiAbstract:In order to explore the damage from metabolites of benzo(a)pyrene on DNA of mammalian Cells, the effects of four metabolites of benzo(a)pyrene (anti-BPDE, syn-BPDE, 3-OH-BP and 9-OH-BP) on synthesis of DNA and unschedule DNA synthesis (UDS) in BALB/3T3 Cells were assayed, by methods of single-labeling and double-labeling. The results showed that all of the four agents were able to increase the synthesis of DNA, but only three of them (apart from syn-BPDE) induced UDS in BALB/3T3 Cells. The above indicates that the metabolites of benzo(a)pyrene are able to damage DNA in BALB/3T3 Cells, and that this effect may be relative to the sterical structure of metabolites of benzo(a)pyrene.
Renger F. Witkamp - One of the best experts on this subject based on the ideXlab platform.
-
Tiamulin inhibits human CYP3A4 activity in an NIH/3T3 Cell Line stably expressing CYP3A4 cDNA
Biochemical pharmacology, 1995Co-Authors: Els M. De Groene, S. M. Nijmeijer, G.jean Horbach, Renger F. WitkampAbstract:Tiamulin is an antibiotic frequently used in veterinary medicine. The drug has been shown to produce clinically important interactions with other compounds that are administered simultaneously. An NIH/3T3 Cell Line, stably expressing human cytochrome P450 (EC 1.14.14.1) cDNA (CYP3A4), was used to study the effect of tiamulin on CYP3A4 activity. The 6 beta-hydroxylation activity of testosterone, which is increased in CYP3A4-expressing Cells compared to vector-transfected Cells, showed reduced activity after incubation with 1 microM tiamulin and was completely reduced to background level after incubation with 2, 5 and 10 microM tiamulin. The CYP3A4-expressing Cell Line was used in combination with a shuttle vector containing the bacterial lacZ' gene to study the effect of tiamulin on CYP3A4-mediated mutagenicity of aflatoxin B1. The mutation frequency of aflatoxin B1 could be completely inhibited by tiamulin in CYP3A4-expressing Cells, but no effect was observed on the mutation frequency of the direct mutagen ethylmethanesulphonate. Western blotting of homogenates of the CYP3A4-expressing Cell Line showed stabilization of CYP3A4 protein after incubation with tiamulin, supporting the hypothesis that the mechanism of inhibition is by binding of tiamulin to the cytochrome.
-
tiamulin inhibits human cyp3a4 activity in an nih 3T3 Cell Line stably expressing cyp3a4 cdna
Biochemical Pharmacology, 1995Co-Authors: Els M. De Groene, S. M. Nijmeijer, Jean G Horbach, Renger F. WitkampAbstract:Tiamulin is an antibiotic frequently used in veterinary medicine. The drug has been shown to produce clinically important interactions with other compounds that are administered simultaneously. An NIH/3T3 Cell Line, stably expressing human cytochrome P450 (EC 1.14.14.1) cDNA (CYP3A4), was used to study the effect of tiamulin on CYP3A4 activity. The 6 beta-hydroxylation activity of testosterone, which is increased in CYP3A4-expressing Cells compared to vector-transfected Cells, showed reduced activity after incubation with 1 microM tiamulin and was completely reduced to background level after incubation with 2, 5 and 10 microM tiamulin. The CYP3A4-expressing Cell Line was used in combination with a shuttle vector containing the bacterial lacZ' gene to study the effect of tiamulin on CYP3A4-mediated mutagenicity of aflatoxin B1. The mutation frequency of aflatoxin B1 could be completely inhibited by tiamulin in CYP3A4-expressing Cells, but no effect was observed on the mutation frequency of the direct mutagen ethylmethanesulphonate. Western blotting of homogenates of the CYP3A4-expressing Cell Line showed stabilization of CYP3A4 protein after incubation with tiamulin, supporting the hypothesis that the mechanism of inhibition is by binding of tiamulin to the cytochrome.
Okunola A. Alabi - One of the best experts on this subject based on the ideXlab platform.
-
electronic waste leachate mediated dna fragmentation and Cell death by apoptosis in mouse fibroblast nih 3T3 Cell Line
Ecotoxicology and Environmental Safety, 2013Co-Authors: Okunola A. Alabi, Adekunle A. Bakare, Jelver Sierra, Fabiola Branco Filippinmonteiro, Tânia B CreczynskipasaAbstract:Abstract This study investigated the apoptotic effect of electronic waste on fibroblast Cell Line. Cells were treated with different concentrations of the leachate for 24 h. Cell viability was detected by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, nuclear morphology of Cells was explored by acridine orange (AO)/ethidium bromide (EB) double staining, mitochondrial membrane potential was evaluated using JC-1 probe while Cell cycle analysis was conducted using flow cytometry. The oxidative status was detected using DCFH-DA (dichlorofluorescin diacetate) probe and the relationship between Cell death and ROS (reactive oxygen species) was investigated using N -acetylcysteine. Results showed an increased Cell death as detected by MTT assay and AO/EB staining. Cell cycle analysis indicated an induction of sub/G1 events while JC-1 probe showed significant disruption of mitochondrial membrane potential. There was significant induction of ROS, while N -acetylcysteine protected the Cells from DNA damage. These suggest apoptotic pathway as a possible mechanism of e-waste induced cyto-genotoxicity.
-
Electronic waste leachate-mediated DNA fragmentation and Cell death by apoptosis in mouse fibroblast (NIH/3T3) Cell Line
Ecotoxicology and environmental safety, 2013Co-Authors: Okunola A. Alabi, Adekunle A. Bakare, Fabíola Branco Filippin-monteiro, Jelver Sierra, Tânia B. Creczynski-pasaAbstract:Abstract This study investigated the apoptotic effect of electronic waste on fibroblast Cell Line. Cells were treated with different concentrations of the leachate for 24 h. Cell viability was detected by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, nuclear morphology of Cells was explored by acridine orange (AO)/ethidium bromide (EB) double staining, mitochondrial membrane potential was evaluated using JC-1 probe while Cell cycle analysis was conducted using flow cytometry. The oxidative status was detected using DCFH-DA (dichlorofluorescin diacetate) probe and the relationship between Cell death and ROS (reactive oxygen species) was investigated using N -acetylcysteine. Results showed an increased Cell death as detected by MTT assay and AO/EB staining. Cell cycle analysis indicated an induction of sub/G1 events while JC-1 probe showed significant disruption of mitochondrial membrane potential. There was significant induction of ROS, while N -acetylcysteine protected the Cells from DNA damage. These suggest apoptotic pathway as a possible mechanism of e-waste induced cyto-genotoxicity.
