The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
I Emerit - One of the best experts on this subject based on the ideXlab platform.
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Clastogenic plasma factors in psoriasis--comparison of phototherapy and anti-TNF-α treatments.
Photochemistry and photobiology, 2011Co-Authors: I Emerit, Joana Antunes, João M. N. Silva, João P. Freitas, Teresa Pinheiro, Paulo FilipeAbstract:As previously described, Psoralen plus UVA (PUVA) therapy induces chromosome damage in psoriatic patients. This study evaluates whether these effects are transitory or persistent. In addition, we studied these effects after narrowband UVB (nUVB) and anti-tumor necrosis factor (TNF)-α treatments. Among 40 responder patients, 10 received PUVA, 10 nUVB, 10 Infliximab and 10 Etanercept. Disease activity was determined with Psoriasis Area and Severity Index. Chromosomal breakage was evaluated by the Clastogenic factor (CF) test. Potential Clastogenic agents, malondialdehyde (MDA) and TNF-α were measured. Before treatment, the plasma-adjusted Clastogenic scores (ACS) of patients were increased. During treatment, a further increase in ACS was observed in both phototherapy groups. Chromosome damage persisted for PUVA patients at week 32, while it diminished after nUVB to ACS values lower than before treatment. MDA and TNF-α values were also increased at baseline. MDA decreased during treatment in all groups, but without reaching normal levels. Plasma TNF-α remained unchanged in PUVA and nUVB but decreased in both anti-TNF-α treatment groups. Psoriasis is accompanied by CF-induced chromosomal breakage that increases during PUVA and nUVB treatments. Plasma Clastogenic activity persisted in the follow-up after PUVA, while after nUVB ACS returned to values even lower than baseline. Clastogenic activity during the induction phase with anti-TNF-α remained unchanged.
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Clastogenic factors as biomarkers of oxidative stress in chronic hepatitis C.
Digestion, 2000Co-Authors: I Emerit, João P. Freitas, Paulo Filipe, Fátima Serejo, Amina Alaoui Youssefi, Afonso Fernandes, Adilia Costa, Fernando Silva Ramalho, Amelia Baptista, Miguel Carneiro De MouraAbstract:Background/Aims: Clastogenic factors (CFs) are composed of lipid peroxidation products, cytokines and other oxidants with chromosome-damaging properties. They are regularly observed
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Clastogenic factors in the plasma of children exposed at Chernobyl.
Mutation research, 1997Co-Authors: I Emerit, A. Levy, L. Cernjavski, John R. Goldsmith, Michael R. Quastel, L Merkin, A Alaoui-youssefi, A Pogossian, E. RiklisAbstract:Clastogenic factors (CFs), as they were described previously in accidentally or therapeutically irradiated persons, in A-bomb survivors and in liquidators of the Chernobyl nuclear power plant, were also detected in the plasma of Chernobyl-exposed children. A high percentage of plasma ultrafiltrates from 170 children, immigrated to Israel in 1990, exerted Clastogenic effects in test cultures set up with blood from healthy donors. The differences were highly significant in comparison to children immigrated from 'clean' cities of the former Soviet Union or children born in Israel. The percentage of CF-positive children and the mean values of the adjusted Clastogenic scores (ACS) were higher for those coming from Gomel and Mozyr, which are high exposure sites (IAEA measurements), compared to those coming from Kiev. There was no correlation between residual 137-Caesium body burden and presence of CFs. However, both measurements were not done at the same time (in 1990 and 1992-1994, respectively). Also no relationship could be revealed between enlargement of the thyroid gland and CF-positivity. CFs are not only observed after irradiation, but in a variety of chronic inflammatory diseases with autoimmune reactions. They were also described in the congenital breakage syndromes, which are hereditary diseases with the highest cancer incidence in humans. Whether the Clastogenic effects continuously produced by circulating CFs represent a risk factor for malignant late effects deserves further study and follow-up. Since CF formation and CF action are mediated by superoxide radicals, prophylactic treatment with antioxidants may be suggested for Chernobyl-exposed children, whose plasma induces a strongly positive CF-test.
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Clastogenic Activity in the Plasma of Scleroderma Patients: A Biomarker of Oxidative Stress
Dermatology (Basel Switzerland), 1997Co-Authors: I Emerit, João P. Freitas, Paulo Filipe, P. Meunier, C. Auclair, A. Deroussent, A. Gouyette, A. FernandesAbstract:Background: Scleroderma patients exhibit increased chromosomal instability due to circulating Clastogenic plasma factors (CF). Formation and action mechanisms of CF are mediated by
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Oxyradical-mediated Clastogenic Plasma Factors in Psoriasis: Increase in Clastogenic Activity after PUVA
Photochemistry and photobiology, 1997Co-Authors: Paulo Filipe, I Emerit, A. Levy, L. Cernjavski, A. Alaoui Youssefi, José Guilherme De Freitas, J. L. Cirne De CastroAbstract:— Psoriasis is a common skin disorder characterized by hyperproliferation and incomplete differentiation of epidermal keratinocytes. Psoralen plus UVA (PUVA) is one of the treatments proposed for this disease. We had reported previously that exposure of regular blood cultures from healthy donors to PUVA leads to chromosomal breakage via the formation of transferable Clastogenic materials, a phenomenon inhibitable by superoxide dismutase. In the present paper we show that these Clastogenic factors (CF) are also formed in vivo. The CF were found in about 50% of the psoriasis patients studied (14 out of 31). In PUVA-treated psoriasis patients, the Clastogenic activity of the plasma increased significantly between the first and the last (16th) exposure to PUVA. We hypothesize that CF formation in psoriasis is similar to that in other diseases accompanied by oxidative stress, in particular chronic inflammatory diseases with autoimmune reactions such as lupus erythematosus, progressive systemic sclerosis, rheumatoid arthritis and others. Increased superoxide production by phagocytes, formation of lipid peroxidation products and release of cytokines are considered to be responsible for the superoxide-stimulating and chromosome-damaging properties of patients' plasma. During PUVA therapy, superoxide generated via the interaction of psoralen with UVA may contribute to CF formation in addition to superoxide from inflammatory cells. An increased risk of cancer and leukemia is observed in diseases accompanied by CF formation. Therefore CF may contribute to the well-known risk of photocarcinogenesis by PUVA therapy. This additional risk may be preventable by antioxidants and superoxide scavengers.
Akhilesh C. Singh - One of the best experts on this subject based on the ideXlab platform.
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Clastogenicity of lanthanides--induction of micronuclei in root tips of Vicia faba.
Mutation research, 1994Co-Authors: Anand M. Jha, Akhilesh C. SinghAbstract:The Clastogenic property of two lanthanides, Praseodymium and Neodymium, was evaluated by scoring the frequencies of micronucleated cells in the interphase and chromosome/chromatid aberrations at ana-telophases in root tips of Vicia faba L. The significant increase in the frequency of micronucleated cells coupled with the increase in the frequency of chromosome/chromatid bridges and lagging chromosomes/chromatids suggest that these two are Clastogenic for Vicia faba root cells.
A. Levy - One of the best experts on this subject based on the ideXlab platform.
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Clastogenic factors in the plasma of children exposed at Chernobyl.
Mutation research, 1997Co-Authors: I Emerit, A. Levy, L. Cernjavski, John R. Goldsmith, Michael R. Quastel, L Merkin, A Alaoui-youssefi, A Pogossian, E. RiklisAbstract:Clastogenic factors (CFs), as they were described previously in accidentally or therapeutically irradiated persons, in A-bomb survivors and in liquidators of the Chernobyl nuclear power plant, were also detected in the plasma of Chernobyl-exposed children. A high percentage of plasma ultrafiltrates from 170 children, immigrated to Israel in 1990, exerted Clastogenic effects in test cultures set up with blood from healthy donors. The differences were highly significant in comparison to children immigrated from 'clean' cities of the former Soviet Union or children born in Israel. The percentage of CF-positive children and the mean values of the adjusted Clastogenic scores (ACS) were higher for those coming from Gomel and Mozyr, which are high exposure sites (IAEA measurements), compared to those coming from Kiev. There was no correlation between residual 137-Caesium body burden and presence of CFs. However, both measurements were not done at the same time (in 1990 and 1992-1994, respectively). Also no relationship could be revealed between enlargement of the thyroid gland and CF-positivity. CFs are not only observed after irradiation, but in a variety of chronic inflammatory diseases with autoimmune reactions. They were also described in the congenital breakage syndromes, which are hereditary diseases with the highest cancer incidence in humans. Whether the Clastogenic effects continuously produced by circulating CFs represent a risk factor for malignant late effects deserves further study and follow-up. Since CF formation and CF action are mediated by superoxide radicals, prophylactic treatment with antioxidants may be suggested for Chernobyl-exposed children, whose plasma induces a strongly positive CF-test.
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Oxyradical-mediated Clastogenic Plasma Factors in Psoriasis: Increase in Clastogenic Activity after PUVA
Photochemistry and photobiology, 1997Co-Authors: Paulo Filipe, I Emerit, A. Levy, L. Cernjavski, A. Alaoui Youssefi, José Guilherme De Freitas, J. L. Cirne De CastroAbstract:— Psoriasis is a common skin disorder characterized by hyperproliferation and incomplete differentiation of epidermal keratinocytes. Psoralen plus UVA (PUVA) is one of the treatments proposed for this disease. We had reported previously that exposure of regular blood cultures from healthy donors to PUVA leads to chromosomal breakage via the formation of transferable Clastogenic materials, a phenomenon inhibitable by superoxide dismutase. In the present paper we show that these Clastogenic factors (CF) are also formed in vivo. The CF were found in about 50% of the psoriasis patients studied (14 out of 31). In PUVA-treated psoriasis patients, the Clastogenic activity of the plasma increased significantly between the first and the last (16th) exposure to PUVA. We hypothesize that CF formation in psoriasis is similar to that in other diseases accompanied by oxidative stress, in particular chronic inflammatory diseases with autoimmune reactions such as lupus erythematosus, progressive systemic sclerosis, rheumatoid arthritis and others. Increased superoxide production by phagocytes, formation of lipid peroxidation products and release of cytokines are considered to be responsible for the superoxide-stimulating and chromosome-damaging properties of patients' plasma. During PUVA therapy, superoxide generated via the interaction of psoralen with UVA may contribute to CF formation in addition to superoxide from inflammatory cells. An increased risk of cancer and leukemia is observed in diseases accompanied by CF formation. Therefore CF may contribute to the well-known risk of photocarcinogenesis by PUVA therapy. This additional risk may be preventable by antioxidants and superoxide scavengers.
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Transferable Clastogenic activity in plasma from patients with Fanconi anemia.
Human genetics, 1995Co-Authors: I Emerit, A. Levy, G. Pagano, L. Pinto, R. Calzone, Adriana ZatteraleAbstract:The present study was conducted on 13 patients with Fanconi anemia, 25 parents and 12 siblings. The chromosomal instability characteristic of this congenital breakage syndrome was associated with the presence of transferable Clastogenic material in the plasma, as also reported previously for ataxia telangiectasia and Bloom's syndrome. While all plasma ultrafiltrates from homozygotes had chromosome damaging properties, the Clastogenic material had to be concentrated in most heterozygotes to reach detectable levels. The Clastogenic effect was exerted via the intermediacy of superoxide radicals, since it was regularly inhibited by superoxide dismutase (SOD). This adds further evidence for a prooxidant state in this hereditary disease. The autosustained Clastogenic activity possibly plays a role in the progressive impairment of blood cell-producing bone marrow and may predispose patients to develop cancer and leukemia. Prophylactic use of antioxidants may be recommended, using Clastogenic plasma activity as a guide.
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Clastogenic factors in the plasma of Chernobyl accident recovery workers: AntiClastogenic effect of Ginkgo biloba extract
Radiation research, 1995Co-Authors: I Emerit, A. Levy, N. Oganesian, T. Sarkisian, R. Arutyunyan, A. Pogosian, K. Asrian, L. CernjavskiAbstract:Clastogenic factors are found in the plasma of persons irradiated accidentally or therapeutically. They persisted in the plasma of A-bomb survivors over 30 years. Clastogenic factors were found in 33 of 47 Chernobyl accident recovery workers (often referred to as liquidators) in a previous study (I. Emerit et al., J. Cancer Res. Clin. Oncol. 120, 558-561, 1994). In the present study, we show that there is a positive correlation between Clastogenic activity and dose and that these biomarkers of oxidative stress can be influenced successfully by appropriate antioxidant treatment. With the authorization of the Armenian Ministry of Health, 30 workers were treated with antioxidants from Ginkgo biloba leaves. The extract EGb 761 containing flavonoids and terpenoids was given at a daily dose of 3 x 40 mg (Tanakan, IPSEN, France) during 2 months. The Clastogenic activity of the plasma was reduced to control levels on the first day after the end of the treatment. A 1-year follow-up showed that the benefit of the treatment persisted for at least 7 months. One-third of the workers again had Clastogenic factors after 1 year, demonstrating that the process which produced Clastogenic factors continued. However, the observation that antioxidants do not have to be given continuously is encouraging for intervention trials on a large-scale basis. These appear justified, since Clastogenic factors are thought to be risk factors for the development of late effects of irradiation.
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Transferable Clastogenic activity in plasma from persons exposed as salvage personnel of the Chernobyl reactor.
Journal of cancer research and clinical oncology, 1994Co-Authors: I Emerit, A. Levy, T. Sarkisian, R. Arutyunyan, A. Pogosian, L. Cernjavski, N. Oganesyan, H. Mejlumian, M. Gulkandanian, Michael R. QuastelAbstract:Clastogenic factors were first described in the plasma of people who had been accidentally or therapeutically irradiated. They were found also in A-bomb survivors, where they persisted for many years after the irradiation. The present study searched for these factors in the plasma of 32 civil workers from Armenia, who had been engaged as “liquidators” around the Chernobyl atomic power station in 1986. It also included 15 liquidators who had emigrated from the ex-Soviet Union to Israel. Reference plasma samples were obtained from 41 blood donors from the Armenian Blood Center in Yerevan. The samples were tested for their Clastogenic activity in blood cultures from healthy donors. The majority of results from the liquidators exceeded those from the unexposed reference samples. The samples from the first Armenian group, with the higher average irradiation dose (0.6±0.6 Gy), were more Clastogenic than those from the second group exposed to 0.2±0.2 Gy. The number of aberrations in the test cultures was 17.9±2.9% and 10.5±3.8% respectively, compared to 5.7±3.2% in the cultures exposed to the reference ultrafiltrates from Armenian blood donors. The samples from the Israeli liquidators also induced significantly increased aberration rates (14.0±3.9% aberrant cells). The Clastogenic activity was regularly inhibited by superoxide dismutase, indicating that the chromosome-damaging effects of radiation-induced Clastogenic factors are exerted via the intermediation of superoxide radicals, as is known for Clastogenic factors of different origin.
Anand M. Jha - One of the best experts on this subject based on the ideXlab platform.
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Clastogenicity of lanthanides--induction of micronuclei in root tips of Vicia faba.
Mutation research, 1994Co-Authors: Anand M. Jha, Akhilesh C. SinghAbstract:The Clastogenic property of two lanthanides, Praseodymium and Neodymium, was evaluated by scoring the frequencies of micronucleated cells in the interphase and chromosome/chromatid aberrations at ana-telophases in root tips of Vicia faba L. The significant increase in the frequency of micronucleated cells coupled with the increase in the frequency of chromosome/chromatid bridges and lagging chromosomes/chromatids suggest that these two are Clastogenic for Vicia faba root cells.
L. Cernjavski - One of the best experts on this subject based on the ideXlab platform.
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Clastogenic factors in the plasma of children exposed at Chernobyl.
Mutation research, 1997Co-Authors: I Emerit, A. Levy, L. Cernjavski, John R. Goldsmith, Michael R. Quastel, L Merkin, A Alaoui-youssefi, A Pogossian, E. RiklisAbstract:Clastogenic factors (CFs), as they were described previously in accidentally or therapeutically irradiated persons, in A-bomb survivors and in liquidators of the Chernobyl nuclear power plant, were also detected in the plasma of Chernobyl-exposed children. A high percentage of plasma ultrafiltrates from 170 children, immigrated to Israel in 1990, exerted Clastogenic effects in test cultures set up with blood from healthy donors. The differences were highly significant in comparison to children immigrated from 'clean' cities of the former Soviet Union or children born in Israel. The percentage of CF-positive children and the mean values of the adjusted Clastogenic scores (ACS) were higher for those coming from Gomel and Mozyr, which are high exposure sites (IAEA measurements), compared to those coming from Kiev. There was no correlation between residual 137-Caesium body burden and presence of CFs. However, both measurements were not done at the same time (in 1990 and 1992-1994, respectively). Also no relationship could be revealed between enlargement of the thyroid gland and CF-positivity. CFs are not only observed after irradiation, but in a variety of chronic inflammatory diseases with autoimmune reactions. They were also described in the congenital breakage syndromes, which are hereditary diseases with the highest cancer incidence in humans. Whether the Clastogenic effects continuously produced by circulating CFs represent a risk factor for malignant late effects deserves further study and follow-up. Since CF formation and CF action are mediated by superoxide radicals, prophylactic treatment with antioxidants may be suggested for Chernobyl-exposed children, whose plasma induces a strongly positive CF-test.
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Oxyradical-mediated Clastogenic Plasma Factors in Psoriasis: Increase in Clastogenic Activity after PUVA
Photochemistry and photobiology, 1997Co-Authors: Paulo Filipe, I Emerit, A. Levy, L. Cernjavski, A. Alaoui Youssefi, José Guilherme De Freitas, J. L. Cirne De CastroAbstract:— Psoriasis is a common skin disorder characterized by hyperproliferation and incomplete differentiation of epidermal keratinocytes. Psoralen plus UVA (PUVA) is one of the treatments proposed for this disease. We had reported previously that exposure of regular blood cultures from healthy donors to PUVA leads to chromosomal breakage via the formation of transferable Clastogenic materials, a phenomenon inhibitable by superoxide dismutase. In the present paper we show that these Clastogenic factors (CF) are also formed in vivo. The CF were found in about 50% of the psoriasis patients studied (14 out of 31). In PUVA-treated psoriasis patients, the Clastogenic activity of the plasma increased significantly between the first and the last (16th) exposure to PUVA. We hypothesize that CF formation in psoriasis is similar to that in other diseases accompanied by oxidative stress, in particular chronic inflammatory diseases with autoimmune reactions such as lupus erythematosus, progressive systemic sclerosis, rheumatoid arthritis and others. Increased superoxide production by phagocytes, formation of lipid peroxidation products and release of cytokines are considered to be responsible for the superoxide-stimulating and chromosome-damaging properties of patients' plasma. During PUVA therapy, superoxide generated via the interaction of psoralen with UVA may contribute to CF formation in addition to superoxide from inflammatory cells. An increased risk of cancer and leukemia is observed in diseases accompanied by CF formation. Therefore CF may contribute to the well-known risk of photocarcinogenesis by PUVA therapy. This additional risk may be preventable by antioxidants and superoxide scavengers.
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Clastogenic factors in the plasma of Chernobyl accident recovery workers: AntiClastogenic effect of Ginkgo biloba extract
Radiation research, 1995Co-Authors: I Emerit, A. Levy, N. Oganesian, T. Sarkisian, R. Arutyunyan, A. Pogosian, K. Asrian, L. CernjavskiAbstract:Clastogenic factors are found in the plasma of persons irradiated accidentally or therapeutically. They persisted in the plasma of A-bomb survivors over 30 years. Clastogenic factors were found in 33 of 47 Chernobyl accident recovery workers (often referred to as liquidators) in a previous study (I. Emerit et al., J. Cancer Res. Clin. Oncol. 120, 558-561, 1994). In the present study, we show that there is a positive correlation between Clastogenic activity and dose and that these biomarkers of oxidative stress can be influenced successfully by appropriate antioxidant treatment. With the authorization of the Armenian Ministry of Health, 30 workers were treated with antioxidants from Ginkgo biloba leaves. The extract EGb 761 containing flavonoids and terpenoids was given at a daily dose of 3 x 40 mg (Tanakan, IPSEN, France) during 2 months. The Clastogenic activity of the plasma was reduced to control levels on the first day after the end of the treatment. A 1-year follow-up showed that the benefit of the treatment persisted for at least 7 months. One-third of the workers again had Clastogenic factors after 1 year, demonstrating that the process which produced Clastogenic factors continued. However, the observation that antioxidants do not have to be given continuously is encouraging for intervention trials on a large-scale basis. These appear justified, since Clastogenic factors are thought to be risk factors for the development of late effects of irradiation.
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Transferable Clastogenic activity in plasma from persons exposed as salvage personnel of the Chernobyl reactor.
Journal of cancer research and clinical oncology, 1994Co-Authors: I Emerit, A. Levy, T. Sarkisian, R. Arutyunyan, A. Pogosian, L. Cernjavski, N. Oganesyan, H. Mejlumian, M. Gulkandanian, Michael R. QuastelAbstract:Clastogenic factors were first described in the plasma of people who had been accidentally or therapeutically irradiated. They were found also in A-bomb survivors, where they persisted for many years after the irradiation. The present study searched for these factors in the plasma of 32 civil workers from Armenia, who had been engaged as “liquidators” around the Chernobyl atomic power station in 1986. It also included 15 liquidators who had emigrated from the ex-Soviet Union to Israel. Reference plasma samples were obtained from 41 blood donors from the Armenian Blood Center in Yerevan. The samples were tested for their Clastogenic activity in blood cultures from healthy donors. The majority of results from the liquidators exceeded those from the unexposed reference samples. The samples from the first Armenian group, with the higher average irradiation dose (0.6±0.6 Gy), were more Clastogenic than those from the second group exposed to 0.2±0.2 Gy. The number of aberrations in the test cultures was 17.9±2.9% and 10.5±3.8% respectively, compared to 5.7±3.2% in the cultures exposed to the reference ultrafiltrates from Armenian blood donors. The samples from the Israeli liquidators also induced significantly increased aberration rates (14.0±3.9% aberrant cells). The Clastogenic activity was regularly inhibited by superoxide dismutase, indicating that the chromosome-damaging effects of radiation-induced Clastogenic factors are exerted via the intermediation of superoxide radicals, as is known for Clastogenic factors of different origin.