scholarly journals The Repair of DNA Damage Induced in Human Peripheral Lymphocytes with Styrene Oxide

2003 ◽  
Vol 46 (3) ◽  
pp. 95-100 ◽  
Author(s):  
Renata Köhlerová ◽  
Rudolf Štětina
Keyword(s):  
Dna Damage ◽  
Styrene Oxide ◽  
Repair Process ◽  
Dependent Manner ◽  
Peripheral Lymphocytes ◽  
Abasic Sites ◽  
Endonuclease Iii ◽  
Single Strand Breaks ◽  
Human Peripheral Lymphocytes

Isolated human peripheral lymphocytes were treated in vitro with styrene-7, 8–oxide (SO) and the kinetics of the repair of induced DNA damage was assessed by comet assay during further incubation of lymphocytes. Using a modified assay we measured simultaneously the number of single strand breaks in DNA (SSBs) and the sites sensitive to endonuclease III (endo III) that most probably represent abasic sites in DNA molecules. SO induced DNA damage in a dose–dependent manner and both SSBs and endo III sites were removed from the DNA by a repair process with a half time about 2–4 hours. The damage was repaired completely within 12 hours after the treatment.

Inhibition of mitogen-activated proliferation of human peripheral lymphocytes in vitro by propionic acid

1999 ◽  
Vol 96 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Moacir WAJNER ◽  
Kátia D. SANTOS ◽  
Jeanine L. SCHLOTTFELDT ◽  
Maureen P. ROCHA ◽  
Clóvis M. D. WANNMACHER
Keyword(s):  
Propionic Acid ◽  
Concanavalin A ◽  
Methylmalonic Acid ◽  
Cellular Growth ◽  
Propionic Acidaemia ◽  
Pokeweed Mitogen ◽  
Recurrent Infections ◽  
Peripheral Lymphocytes ◽  
Human Peripheral Lymphocytes

Recurrent infections are common features in patients affected by propionic acidaemia (McKusick 232000) and methylmalonic acidaemia (McKusick 251000). Since these disorders are biochemically characterized by tissue accumulation of propionic acid and methylmalonic acid respectively, it is possible that these compounds may act as immunosuppressants. We therefore investigated the effect of propionate and methylmalonate on cellular growth of human peripheral lymphocytes stimulated in vitro by phytohaemagglutinin, concanavalin A and pokeweed mitogen, a recognized test of cellular immunocompetence. Lymphocytes were cultured in flat-bottomed 96-well microplates at 37 ;°C for 96 ;h (phytohaemagglutinin and concanavalin A) or 144 ;h (pokeweed mitogen) in the presence of one mitogen at different concentrations and of one acid added at doses of 1.0, 2.5 or 5.0 ;mM. Cell blastogenesis was measured by the incorporation of tritiated thymidine into cellular DNA and compared with that of identical cultures with no acid added (controls). A consistent and progressive inhibitory effect of propionic acid with increasing concentrations in culture was identified with all mitogens and was more pronounced with pokeweed mitogen. Lymphocyte blastogenesis was not altered in the presence of methylmalonic acid. The effect of propionate was observed only when the drug was added at the beginning (phytohaemagglutinin-activated) or until 24 ;h (concanavalin A- and pokeweed mitogen-activated) of culture. The viability of lymphocytes after treatment with the drug, as assessed by the Trypan Blue exclusion test, revealed no change when compared with the same untreated lymphocytes, indicating no lymphocytotoxic activity. In conclusion, propionic acid, which accumulates in tissues of patients with propionic acidaemia, causes ‘in vitro’ immunosuppression, which may be related to the recurrent infections characteristic of these patients.

scholarly journals A comparison of the in vitro genotoxicity of anticancer drugs idarubicin and mitoxantrone.

2002 ◽  
Vol 49 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Janusz Błasiak ◽  
Ewa Gloc ◽  
Mariusz Warszawski
Keyword(s):  
Dna Damage ◽  
Human Lymphocytes ◽  
Dna Glycosylase ◽  
Oxygen Species ◽  
Anthracycline Antibiotic ◽  
Strand Breaks ◽  
Endonuclease Iii ◽  
Normal Human ◽  
In Vitro Genotoxicity

Idarubicin is an anthracycline antibiotic used in cancer therapy. Mitoxantrone is an anthracycline analog with presumed better antineoplastic activity and lesser toxicity. Using the alkaline comet assaywe showed that the drugs at 0.01-10 microM induced DNA damage in normal human lymphocytes. The effect induced by idarubicin was more pronounced than by mitoxantrone (P < 0.001). The cells treated with mitoxantrone at 1 microM were able to repair damage to their DNA within a 30-min incubation, whereas the lymphocytes exposed to idarubicin needed 180 min. Since anthracyclines are known to produce free radicals, we checked whether reactive oxygen species might be involved in the observed DNA damage. Catalase, an enzyme inactivating hydrogen peroxide, decreased the extent of DNA damage induced by idarubicin, but did not affect the extent evoked by mitoxantrone. Lymphocytes exposed to the drugs and treated with endonuclease III or formamidopyrimidine-DNA glycosylase (Fpg), enzymes recognizing and nicking oxidized bases, displayed a higher level of DNA damage than the untreated ones. 3-Methyladenine-DNA glycosylase II (AlkA), an enzyme recognizing and nicking mainly methylated bases in DNA, increased the extent of DNA damage caused by idarubicin, but not that induced by mitoxantrone. Our results indicate that the induction of secondary malignancies should be taken into account as side effects of the two drugs. Direct strand breaks, oxidation and methylation of the DNA bases can underlie the DNA-damaging effect of idarubicin, whereas mitoxantrone can induce strand breaks and modification of the bases, including oxidation. The observed in normal lymphocytes much lesser genotoxicity of mitoxantrone compared to idarubicin should be taken into account in planning chemotherapeutic strategies.

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