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Tail Moment (tail + moment)

Distribution by Scientific Domains

Life Sciences	54%
Medical Sciences	18%
Chemistry	18%

Selected Abstracts

DNA damage and repair measurements from cryopreserved lymphocytes without cell culture,A reproducible assay for intervention studies

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 7 2006
Jyh-Lurn Chang
Abstract Single-cell gel electrophoresis (the Comet assay) can be used to measure DNA damage and DNA repair capacity (DRC). However, to test DRC of cryopreserved lymphocytes, published methods include steps for cell culturing and phytohemagglutinin stimulation, which may limit use of this assay in intervention studies. We developed a modified Comet assay protocol that allows us to measure DRC from cryopreserved lymphocytes without these in vitro manipulations. Assay reproducibility was evaluated by performing the assay six times on different dates using six aliquots from one blood draw of one individual. The interindividual variation was assessed by performing the assay using one aliquot from six individuals. When ,-irradiation was used as the mutagen, intra-assay coefficients of variation (CVs.) for baseline DNA damage, damage after ,-irradiation exposure, and DRC,measured as tail moment,were 8, 31, and 10%, respectively. Interindividual CVs. were higher. When H2O2 was used as the mutagen, intra-assay CVs. for damage measurements were lower for a protocol modification that included damage and repair at 37°C (CVs. ranging from 8 to 35%) than for the more standard 4°C protocol. Analyzing moment arm,the average distance of DNA migration within the tail,yielded similar results. DNA repair was successfully detected in each experiment. Comparing freshly isolated lymphocytes to cryopreserved lymphocytes from the same individuals' blood draw indicated that DRC was highly correlated when determined using moment arm values. This modified protocol extends the use of the Comet assay to measuring DRC in intervention studies (e.g., dietary interventions) in that it assesses cellular response after cryopreservation without cell culture or other extensive manipulation. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source]

DNA damage in mice treated with sulfur dioxide by inhalation

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2005
Ziqiang Meng
Abstract Sulfur dioxide (SO2) is a ubiquitous air pollutant produced by the burning of fossil fuels. In this study, single-cell gel electrophoresis (the Comet assay) was used to evaluate the DNA damage produced by inhalation exposure of mice to SO2. Male and female mice were housed in exposure chambers and treated with 14.00 ± 1.25, 28.00 ± 1.98, 56.00 ± 3.11, and 112.00 ± 3.69 mg/m3 SO2 for 6 hr/day for 7 days, while control groups were exposed to filtered air. Comet assays were performed on blood lymphocytes and cells from the brain, lung, liver, spleen, kidney, intestine, and testicles of the animals. SO2 caused significant, dose-dependent increases in DNA damage, as measured by Olive tail moment, in all the cell types analyzed from both sexes of mice. The results indicate that inhalation exposure to SO2 damages the DNA of multiple organs in addition to the lung, and suggests that this damage could result in mutation, cancer, and other diseases related to DNA damage. Further work will be required to understand the ultimate toxicological significance of this damage. These data also suggest that detecting DNA damage in blood lymphocytes, using the Comet assay, may serve as a useful tool for evaluating the impact of pulmonary SO2 exposure in human biomonitoring studies. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source]

DNA damage in leukocytes of workers occupationally exposed to arsenic in copper smelters

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2005
Jadwiga Palus
Abstract Inorganic arsenic (i-As) is a known human carcinogen; however, humans continue to be exposed to i-As in drinking water and in certain occupational settings. In this study, we used the Comet assay to evaluate DNA damage in the somatic cells of workers from three Polish copper smelters who were occupationally exposed to i-As. Blood samples were collected from 72 male workers and 83 unexposed male controls and used for the detection of DNA damage, oxidative DNA damage, and DNA damage after a 3-hr incubation in culture. Urine samples were collected to assess the level of exposure. The mean concentration of arsenic metabolites in urine [the sum of arsenite (AsIII), arsenate (AsV), monomethylarsenate (MMA) and dimethylarsenate (DMA)] and the concentrations of DMA (the main metabolite in urine) were higher in workers than in controls, but the differences were not statistically significant. By contrast, the level of DNA damage, expressed as the median tail moment, was significantly higher in the leukocytes of workers than in the controls. Comet assays conducted with formamidopyrimidine glycosylase (FPG) digestion to detect oxidative DNA damage indicated that oxidative lesions were present in leukocytes from both the exposed and control groups, but the levels of damage were significantly higher among the workers. Incubation of the cells in culture resulted in a significant reduction in the levels of DNA damage, especially among leukocytes from the workers, suggesting that the DNA damage was subject to repair. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. Although i-As was present in air samples from the smelters and in urine samples from workers, no clear association could be made between i-As exposure and the DNA damage. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source]

DNA damage assessment by comet assay of human lymphocytes exposed to jet propulsion fuels

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2002
Shawna M. Jackman
Abstract Exposure to jet fuel damages DNA and results in a number of physiological changes in liver, lung, immune, and neurological tissue. In this study the single-cell gel electrophoresis assay or comet assay was used to compare the DNA damage in human peripheral lymphocytes produced by three jet propulsion fuels: JP-8, JP-5, and JP-8+100. These fuels consist of complex mixtures of aliphatic, aromatic, and substituted naphthalene hydrocarbons. Two exposure times were investigated which correspond to estimated occupational exposure times and concentrations of fuels were used that were based on previous fuel toxicity studies. Analysis of samples for the extent of DNA damage as determined by tail moment and percent tail DNA was performed on exposed cells following a brief recovery time. All fuels produced significant increases in DNA damage; however, only JP-8+100 was genotoxic at the lowest exposure concentration (1:500). At the highest exposure concentration (1:75), the mean tail moments for JP-8 and JP-8+100 (32.041 ± 2.599 and 45.774 ± 4.743, respectively) were significantly greater than for JP-5 (1.314 ± 0.474). These results indicate that JP-8+100 is the most potent inducer of DNA damage in human peripheral lymphocytes and that both JP-8+100 and JP-8 are capable of damaging lymphocyte DNA to a greater extent than JP-5. Environ. Mol. Mutagen. 40:18,23, 2002. © 2002 Wiley-Liss, Inc. [source]

Monitoring of DNA breakage in embryonic stages of the African catfish Clarias gariepinus (Burchell, 1822) after exposure to lead nitrate using alkaline comet assay

ENVIRONMENTAL TOXICOLOGY, Issue 6 2008
Alaa G. M. Osman
Abstract Increasing lead contamination in Egyptian ecosystems and high lead concentrations in food items have raised concern for human health and stimulated studies on monitoring ecotoxicological impact of lead-caused genotoxicity. In this work, the alkaline comet assay was modified for monitoring DNA strand breakage in sensitive early life stages of the African catfish Clarias gariepinus. Following exposure to 100, 300, and 500 ,g/L lead nitrate, DNA strand breakage was quantified in embryos at 30, 48, 96, 144, and 168 h post-fertilization (PFS). For quantitative analysis, four commonly used parameters (tail % DNA, %TDNA; head % DNA, %HDNA; tail length, TL; tail moment, TM) were analyzed in 96 nuclei (in triplicates) at each sampling point. The parameter %TDNA revealed highest resolution and lowest variation. A strong correlation between lead concentration, time of exposure, and DNA strand breakage was observed. Here, genotoxicity detected by comet assay preceded the manifested malformations assessed with conventional histology. Qualitative evaluation was carried out using five categories are as follows: undamaged (%TDNA , 10%), low damaged (10% < %TDNA , 25%), median damaged (25 < %TDNA , 50%), highly damaged (50 < %TDNA , 75%), and extremely damaged (%TDNA > 75%) nuclei confirming a dose and time-dependent shift towards increased frequencies of highly and extremely damaged nuclei. A protective capacity provided by a hardened chorion is a an interesting finding in this study as DNA damage in the prehatching stages 30 h-PFS and 48 h-PFS was low in all treatments (qualitative and quantitative analyses). These results clearly show that the comet assay is a sensitive tool for the detection of genotoxicity in vulnerable early life stages of the African catfish and is a method more sensitive than histological parameters for monitoring genotoxic effects. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source]

Endogenous DNA damage and testicular germ cell tumors

INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 6 2009
M. B. Cook
Summary Testicular germ cell tumors are comprised of two histologic groups, seminomas and non-seminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable levels of net endogenous DNA damage. To test our hypothesis, we conducted a case,case analysis of 51 seminoma and 61 non-seminoma patients using data and specimens from the Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort. A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modelled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with non-seminoma compared with seminoma (OR50th percentile = 3.31, 95% CI: 1.00, 10.98; OR75th percentile = 3.71, 95% CI: 1.04, 13.20; p for trend = 0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR50th percentile = 2.27, 95% CI: 0.75, 6.87; OR75th percentile = 2.40, 95% CI: 0.75, 7.71; p for trend = 0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that net endogenous levels are higher in patients who develop non-seminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma. [source]

Naringin, a grapefruit flavanone, protects V79 cells against the bleomycin-induced genotoxicity and decline in survival

JOURNAL OF APPLIED TOXICOLOGY, Issue 2 2007
Abhinav Jagetia
Abstract The effect of naringin, a grapefruit flavonone was studied on bleomycin-induced genomic damage and alteration in the survival of cultured V79 cells. Exposure of V79 cells to bleomycin induced a concentration dependent elevation in the frequency of binucleate cells bearing micronuclei (MNBNC) and a maximum number of MNBNCs were observed in the cells treated with 50 ,g ml,1 bleomycin, the highest concentration evaluated. This genotoxic effect of bleomycin was reflected in the cell survival, where a concentration dependent decline was observed in the cells treated with different concentrations of bleomycin. Treatment of cells with 1 mm naringin before exposure to different concentrations of bleomycin arrested the bleomycin-induced decline in the cell survival accompanied by a significant reduction in the frequency of micronuclei when compared with bleomycin treatment alone. The cell survival and micronuclei induction were found to be inversely correlated. The repair kinetics of DNA damage induced by bleomycin was evaluated by exposing the cells to 10 ,g ml,1 bleomycin using single cell gel electrophoresis. Treatment of V79 cells with bleomycin resulted in a continuous increase in DNA damage up to 6 h post-bleomycin treatment as evident by migration of more DNA into the tails (% tail DNA) of the comets and a subsequent increase in olive tail moment (OTM), an index of DNA damage. Treatment of V79 cells with 1 mm naringin reduced bleomycin-induced DNA damage and accelerated DNA repair as indicated by a reduction in % tail DNA and OTM with increasing assessment time. A maximum reduction in the DNA damage was observed at 6 h post-bleomycin treatment, where it was 5 times lower than bleomycin alone. Our study, which was conducted on the basis of antioxidant, free radical scavenging and metal chelating properties of naringin demonstrates that naringin reduced the genotoxic effects of bleomycin and consequently increased the cell survival and therefore may act as a chemoprotective agent in clinical situations. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Oral malodorous compound causes apoptosis and genomic DNA damage in human gingival fibroblasts

JOURNAL OF PERIODONTAL RESEARCH, Issue 4 2008
K. Yaegaki
Background and Objective:, Volatile sulfur compounds are the main cause of halitosis. Hydrogen sulfide is one of these volatile sulfur compounds and the principal malodorous compound in physiological halitosis. Periodontally pathogenic activities of hydrogen sulfide have been previously reported. Hydrogen sulfide induces apoptotic cell death in aorta smooth muscle cells and in other tissues. Apoptosis plays an important role in the onset and progress of periodontitis. The objective of this study was to determine whether hydrogen sulfide causes apoptosis in human gingival fibroblasts. Material and methods:, Necrotic cells were detected using a lactate dehydrogenase assay. Apoptosis was ascertained using a histone-complexed DNA fragment assay and flow cytometry. The level of caspase 3, a key enzyme in apoptotic signaling, was also measured, and the effects of hydrogen sulfide on reactive oxygen species and superoxide dismutase were assessed. DNA damage caused by hydrogen sulfide was examined by means of single-cell gel electrophoresis. Results:, After 72 h of incubation with 100 ng/mL of hydrogen sulfide, necrosis was found in less than 10% of human gingival fibroblasts, whereas apoptosis was significantly increased (p < 0.05). Superoxide dismutase activity was strongly inhibited, and reactive oxygen species production was enhanced, after 48 and 72 h of incubation. Caspase 3 activity was also increased after 72 h of incubation (p < 0.01). Tail length, percentage of DNA in tail, and tail moment, measured by single-cell gel electrophoresis, were also intensified after 72 h of incubation (p < 0.001). Conclusion:, Hydrogen sulfide caused apoptosis and DNA damage in human gingival fibroblasts. An increased level of reactive oxygen species stimulated by hydrogen sulfide may induce apoptosis and DNA strand breaks. [source]

Effect of different organotin compounds on DNA of gilthead sea bream (Sparus aurata) erythrocytes assessed by the comet assay,

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2002
Rosita Gabbianelli
Abstract The ,comet' assay appears to be a promising tool for estimating DNA damage at the single cell level. We used this test to evaluate the effect of organotin compounds on sea bream nucleated erythrocytes. The tributyltin chloride (TBTC), dibutyltin chloride (DBTC) and monobutyltin chloride (MBTC) employed in this study show different genotoxicities. TBTC and DBTC have pronounced effects on tail length, tail intensity and tail moment, though TBTC is more efficient in producing DNA damage. MBTC leads to a fast genotoxic effect that does not change with the incubation time. The data obtained are important for the analysis of the environmental risks produced by organotin compounds used as antifouling agents in marine paints and as biocides in agriculture. Copyright © 2002 John Wiley & Sons, Ltd. [source]

A combination of soy isoflavone supplementation and exercise improves lipid profiles and protects antioxidant defense-systems against exercise-induced oxidative stress in ovariectomized rats

BIOFACTORS, Issue 4 2007
Hea Young Oh
Abstract Menopause is often accompanied with weight gain, metabolic lipid abnormalities, and oxidative stress. In this study, we investigated the combined effects of exercise and soy isoflavone supplemention on the lipid profiles and antioxidant capacities of ovariectomized rats. Twenty-five female Sprague-Dawley rats were divided into 5 groups: sham-operated, ovariectomized (OVX), OVX with exercise (OVX + EX), OVX with soy isoflavone supplementation (OVX + ISO), and OVX with both soy isoflavones and exercise (OVX + ISO + EX). After 12 weeks of intervention, antioxidant status was evaluated in collected blood samples by the ferric reducing ability of plasma (FRAP), glutathione (GSH) content, and sodium oxide dismutase (SOD) activity. DNA damage in the lymphocytes was determined using alkaline single-cell gel electrophoresis (the Comet assay). Although there were no significant differences in weight gain and food intake, weight gain was lower in OVX + EX, OVX + ISO, and OVX + ISO + EX than in OVX. OVX + EX, OVX + ISO, and OVX + ISO + EX showed a significant decrease in total cholesterol, triglycerides, and LDL-cholesterol compared to OVX. The soy isoflavone supplemented group had significantly increased FRAP values and GSH contents in contrast to no changes in the exercised group, whereas exercise markedly increased SOD activity and H2O2 -induced DNA tail length and tail moment. Exercise with soy isoflavone supplementation significantly increased FRAP values and had no difference on SOD activity, including DNA damage. These results demonstrate that a combined treatment of moderate exercise and soy isoflavone supplementation could exert a beneficial effect on weight control and lipid profiles, and offer protection from exercise-induced oxidative stress in postmenopausal women. [source]