Frequency Of Acentric Fragments Research Articles

In vitro assessment of the antioxidative, toxicological and antimicrobial properties of battery of parabens

The aim of this study was to evaluate antioxidative features using 2,2-diphenyl-1-pycrylhydrazyl free radical (DPPH•) scavenging method, bovine serum albumin (BSA)-binding properties with usage of spectrofluorimetric method, proliferative and cyto/genotoxic status by use of chromosome aberration test, and antimicrobial potential using broth microdilution method, followed by resazurin assay of benzyl-, isopropyl-, isobutyl and phenylparaben in vitro. Our results showed that all parabens had significant antiradical scavenger activity compared to p-hydroxybenzoic acid (PHBA) precursor. Higher mitotic index for benzyl-, isopropyl and isobutylparaben (250 µg/mL) in comparison with control was demonstrated. An increase in the frequency of acentric fragments in lymphocytes treated with benzylparaben and isopropylparaben (125 and 250 µg/mL), and isobutylparaben (250 µg/mL) was observed. Isobutylparaben (250 µg/mL) induced higher number of dicentric chromosomes. An increased number of minute fragments in lymphocytes exposed to benzylparaben (125 and 250 µg/mL) was found. A significant difference in the frequency of chromosome pulverization, between phenylparaben (250 µg/mL) and control, was detected. Benzylparaben (250 µg/mL) and phenylparaben (62.5 µg/mL) caused an increase in the number of apoptotic cells, while isopropylparaben (62.5, 125 and 250 µg/mL) and isobutylparaben (62.5 and 125 µg/mL) induced higher frequency of necrosis. Minimum inhibitory concentration (MIC) of tested parabens ranged 15.62–250 µg/mL for bacteria, and 125–500 µg/mL for the yeast. Minimum microbiocidal concentration ranged 31.25 to 500 µg/mL, and 250 to 1000 µg/mL in bacteria and fungi respectively. The lowest MICs for bacteria were observed for phenyl- (15.62 µg/mL) and isopropylparaben (31.25 µg/mL) against Enterococcus faecalis.

Analysis of biomarkers in a Czech population exposed to heavy air pollution. Part II: chromosomal aberrations and oxidative stress

Populations living in industrialised regions are at higher risk of a number of diseases and shortened life span. These negative effects are primarily brought about by damage to cells and macromolecules caused by environmental pollutants. In this study, we analysed the effect of exposure to benzo[a]pyrene, a particulate matter of aerodynamic diameter < 2.5 µm (PM2.5), and benzene on oxidative stress markers [including 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), 15-F(2t)-isoprostane (15-F2t-IsoP) and protein carbonyls] and cytogenetic parameters (stable and unstable chromosomal aberrations). The samples were collected from subjects living in the Ostrava region characterised by very high levels of air pollution and in Prague with comparatively lower concentrations of pollutants in three seasons (winter 2009, summer 2009 and winter 2010). Despite several-fold higher concentrations of air pollutants in the Ostrava region, the levels of stable aberrations (genomic frequency of translocations per 100 cells, percentage of aberrant cells and frequency of acentric fragments) were mostly comparable in both locations. The frequency of unstable aberrations measured as the number of micronuclei was unexpectedly significantly lower in the Ostrava region subjects in both seasons of 2009. Urinary excretion of 8-oxodG did not differ between locations in either season. Lipid peroxidation measured as levels of 15-F2t-IsoP in blood plasma was elevated in the Ostrava subjects sampled in 2009. Protein oxidation was higher in Prague samples collected in summer 2009. Multivariate analyses conducted separately in subjects from Prague and Ostrava showed a negative association between the frequency of micronuclei and concentrations of benzo[a]pyrene and PM2.5 in both regions. A positive relationship was observed between lipid peroxidation and air pollution; protein oxidation seems to be positively affected by PM2.5 in both regions.

Cytogenetic analysis of an exposed-referent study: perchloroethylene-exposed dry cleaners compared to unexposed laundry workers

BackgroundSignificant numbers of people are exposed to tetrachloroethylene (perchloroethylene, PCE) every year, including workers in the dry cleaning industry. Adverse health effects have been associated with PCE exposure. However, investigations of possible cumulative cytogenetic damage resulting from PCE exposure are lacking.MethodsEighteen dry cleaning workers and 18 laundry workers (unexposed controls) provided a peripheral blood sample for cytogenetic analysis by whole chromosome painting. Pre-shift exhaled air on these same participants was collected and analyzed for PCE levels. The laundry workers were matched to the dry cleaners on race, age, and smoking status. The relationships between levels of cytological damage and exposures (including PCE levels in the shop and in workers' blood, packyears, cumulative alcohol consumption, and age) were compared with correlation coefficients and t-tests. Multiple linear regressions considered blood PCE, packyears, alcohol, and age.ResultsThere were no significant differences between the PCE-exposed dry cleaners and the laundry workers for chromosome translocation frequencies, but PCE levels were significantly correlated with percentage of cells with acentric fragments (R2 = 0.488, p < 0.026).ConclusionsThere does not appear to be a strong effect in these dry cleaning workers of PCE exposure on persistent chromosome damage as measured by translocations. However, the correlation between frequencies of acentric fragments and PCE exposure level suggests that recent exposures to PCE may induce transient genetic damage. More heavily exposed participants and a larger sample size will be needed to determine whether PCE exposure induces significant levels of persistent chromosome damage.

Influence of postwash time on the mutagenic effects of ethylmethanesulphonate (EMS) in barley seeds

Barley seeds were presoaked in water for 17 hours and given a treatment with ethylmethanesulphonate (EMS). After treatment the seed samples were washed in running tap water for 4 and 20 hours. Chlorophyll mutations were analysed in the M2 generation and a higher mutation frequency was found in the seeds that had been given a short postwash than in those given a long postwash. Chromosome aberrations were analysed in the first mitotic cycle in the embryo shoot tip. The frequencies of acentric fragments in anaphase cells were not influenced by the duration of postwash. When seeds were redried and stored for 7 days before germination a considerable storage effect was found. The frequency of chromosome aberrations was doubled and the chlorophyll mutation frequency increased several times.

Cytogenetic analysis of children under long-term antibacterial therapy with nitroheterocyclic compound furagin

Cytogenetic analysis of chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) was performed in 109 blood samples from 95 pediatric patients with urinary tract infections (UTIs). Children were exposed to diagnostic levels of X-rays during voiding cystourethrography and subsequently treated for one to 12 months with low doses of furagin — N-(5-nitro-2-furyl)-allylidene-1-aminohydantoin. Furagin is 2-substituted 5-nitrofuran, chemically and structurally similar to well-known antibacterial compound nitrofurantoin. Increased frequencies of CAs were found in children undergoing voiding cystourethrography as compared with the unexposed, acentric fragments being the most frequent alteration (2.03 versus 0.88 per 100 cells, P=0.006). However, a significant decrease in the frequency of acentric fragments was determined with the time elapsed since X-ray examination was performed. A time-independent increase in SCE frequency was found in lymphocytes of children treated with furagin. Total CA frequency did not differ significantly between groups of children with various duration of furagin treatment. However, frequency of chromatid exchanges (triradials and quadriradials) increased significantly with duration of treatment.

Comparison of radiation-induced aberration frequencies in chromosomes 1 and 2 of two human donors

Purpose: The purpose of this study was to analyse donor and time dependent variations in the frequencies of radiation-induced aberrations in chromosomes 1 and 2. Materials and methods: Human lymphocytes from two donors were irradiated with 1 and 2 Gy of X-rays. Chromosomal aberrations were scored in chromosomes 1 and 2 painted with different fluorochromes and in Giemsa stained cells. Two time displaced experiments were performed with lymphocytes of each donor. Results: In cells of both donors chromosome 1 was generally more frequently involved in translocations than chromosome 2. This result was not always reproducible. Chromosome 2 showed a higher frequency of acentric fragments, especially following a dose of 1 Gy. Again interexperimental variations were observed. No differences between the two chromosomes were seen with regard to other aberration types. Both chromosomes showed less dicentrics and more acentric fragments than proportional to their DNA content. Conclusions: Chromosomes 1 and 2 show a different sensitivity to ionizing radiation. The difference is dependent on the aberration type and is not always reproducible. This variability could contribute to the difficulty in reaching a consensus regarding the radiosensitivity of individual chromosomes.

The fate of X-ray-induced chromosome aberrations in blood lymphocyte culture

The BrdU-Giemsa method which facilitates an unequivocal identification of metaphases at different cycles has been utilized to investigate the fate of X-ray-induced chromosome aberrations in the blood lymphocyte culture system of the Indian muntjac which has been the lowest diploid number ( 2n = 6♀/7♂) and easily distinguishable large-sized chromosomes. The results demonstrate that about 50% of dicentrics and only 12% of rings were transmitted from the first cycle to the second. There were as high as 73% abnormal cells in the second cycle as against 94% in the first cycle following 4.0 Gy. However, the frequencies of dicentrics, rings and of abnormal cells were greatly reduced in the third+ cycles. The frequencies of acentric fragments per post-irradiated first, second and third+ division cell were 2.21, 0.64 and 0.24, respectively. In sharp contrast to all earlier reports, about 75% of them were retained as a single acentric fragment in the second cycle. Analysis of fragment segregation during anaphase separation supports this finding. The survival probability of dicentrics and rings was found to be more than 60% in the second and only 18% in the third+ cycle.

Chromosomal aberrations in human lymphocytes irradiated in vitro from donors (males and females) of varying age.

SummaryPHA-stimulated peripheral blood lymphocytes of 43 donors, females and males of the age 0 (newborn) to 72 years, were irradiated in vitro with a constant dose of x-rays (300 rads) at 37°c. The cells were studied in the metaphase of the first mitosis and scored for the presence of chromosomal aberrations. No difference in the yield of the latter in lymphocytes from males and females could be detected. Whereas the frequency of acentric fragments, rings and intercalary deletions was independent of the donors' ages, the yield of dicentrics was linearly and negatively correlated with this parameter. The average decrease of the dicentric yield with age amounted to 0·4 per cent per year, when related to the frequency per cell in the newborn.After a constant x-ray dose, no individual variation was observed in the yield of rings, intercalary deletions and dicentrics, if the age effect for the last aberration type was corrected for. The yield of acentric fragments displayed a significant donor-to-donor variation.