Exchanges In Human Lymphocytes Research Articles

The Effects of Aflatoxin B1 on Chromosome Aberrations and Sister Chromatid Exchanges in Human Lymphocytes

Aflatoxin B1 (AFB1) is a ubiquitous mycotoxin produced by toxicogenic Aspergillus species. AFB1 has been reported to cause serious adverse health effects, such as cancers and abnormal development and reproduction, in animals and humans. The aim of this study was to investigate the ability of aflatoxin B1 (AFB1) to induce chromosome aberrations (CA) and sister chromatid exchanges (SCE) in human lymphocytes. AFB1 exposure significantly increased the number of CA and the frequency of SCE when compared with the control group. This significant increase in CAs as well as SCE may be attributed to the fact that AFB1 can induce genotoxicity through DNA damage. Thus, the present study indicates that AFB1 was genotoxic in human lymphocytes.

Different patterns of chromosome exchange induced by methyl-metanesulphonate and mitomycin C in human cells.

A comparison between 72 chromosome exchanges in human lymphocytes induced by methyl-metanesulphonate (MMS) and 84 exchanges induced by mitomycin C (MC) revealed a different pattern. The prevalence of attenuations, lateral extensions and exchanges in the secondary constrictions of chromosomes 1, 9, and 16 in the MC-treated material is not found with MMS. This may be due to a specific gathering effect of MC upon this particular chromatin. Both materials show a prevalence of C-band exchange, which may be due to repetitious DNA.

No synergism between caffeine and saccharin in the induction of sister chromatid exchange in human lymphocytes.

No synergism between caffeine and saccharin in the induction of sister chromatid exchange in human lymphocytes.

Bromodeoxyuridine-induced sister chromatid exchanges in human lymphocytes.

Human lymphocytes were cultivated for 75 hours in the presence of various concentrations of bromodeoxyuridine (BrdU). The cells were stained with the fluorochrome Hoechst 33258 plus Giemsa. Cells in the first, second and third division could be distinguished, as well as sister chromatid exchanges (SCE) and centromeric exchanges (CME). BrdU-concentrations higher than 100 μM decreased the relative number of cells in the third division and increased the number of cells in the first division in vitro, indicating that higher BrdU-concentrations considerably inhibit cell propagation. The frequency of SCE and CME increased significantly for each stepwise rise in the BrdU concentration between 20–500 μM, suggesting that the vast majority of SCE and CME are induced by BrdU. The average frequency of SCE per cell in 100 μM of BrdU ranged between 18–28 for 8 control subjects with a group mean of 22.2±3.4. BrdU-induced SCE were found to be equally distributed between chromosomes in relation to their lengths while the frequency of CME was independent of chromosome length. High concentrations of BrdU (200–500 μM) significantly increased the number of chromosome aberrations in the cells of all of four subjects investigated. The aberrations were mainly chromosome breaks.

The frequency of sister chromatid exchanges in human lymphocytes treated with ethanol and acetaldehyde

The frequency of sister chromatid exchanges in human lymphocytes treated with ethanol and acetaldehyde

Effects of Thymus kotschyanus var. glabrescens Boiss. extract on mitomycin-C induced chromosomal aberrations and sister chromatid exchanges in human lymphocytes

In this investigation, clastogenic effects of Thymus kotschyanus var. glabrescens Boiss. extract (TE) and anticlastogenic effects of this extract against Mitomycin C (MMC) induced chromosome damage have been evaluated in human peripheral blood lymphocytes in vitro. Two series of experiments were conducted. In the first, only 10(-5), 10(-4), 10(-3) and 10(-2) mul ml(-1) concentrations of TE were used for 48 h to detect potential clastogenicity. In the second, MMC (0.38 mug ml(-1)) plus 10(-5), 10(-4), 10(-3) and 10(-2) mul ml(-1) concentrations of TE were used for 48 h to determine anticlastogenic effects. TE did not increase sister chromatid exchanges (SCEs) (except 10(-2) mul ml concentration) and chromosome aberrations (CAs) significantly compared with negative and solvent controls. However, it decreased the frequency of MMC induced chromosome aberrations. Decreasing was significant at 10(-4), 10(-3) and 10(-2) mul ml(-1) concentrations. On the other hand, TE significantly increased MMC-induced SCEs for all treatment groups compared with positive control.

Investigating thein vitroeffect of taurine on the infant lymphocytes by sister chromatid exchange

Taurine (2-aminoethane sulphonic acid) is normally present in most mammalian tissues and the most abundant free amino acid in lymphocytes. It participates in various important physiological activities including modulation of the functioning of the central nervous system, cell proliferation, viability and prevention of oxidant-induced injury in many tissues. Its levels in human milk are very high which may be the most important difference from cow's milk. In contrast, an inverse association between breast-feeding and carcinogenesis in childhood or later in life has been suggested by several studies. The study group consisted of eight healthy infants. Peripheral blood was collected and lymphocytes were cultured with either Taurine or Mitomycin C (MMC). Sister chromatid exchange in lymphocytes of the infants were calculated. Statistical differences were found between untreated and MMC-treated lymphocytes, untreated and MMC plus taurine-treated lymphocytes, and between MMC and MMC plus taurine-treated lymphocytes (P = 0.012). The results indicated that taurine plays a protective role in MMC-induced sister chromatid exchange in human lymphocytes. The authors suggest that the high levels of taurine found in human milk may induce protecting effects from breast-feeding against DNA damage and malignancy.

Desflurane anaesthesia increases sister chromatid exchange in human lymphocytes

Acta Anaesthesiologica ScandinavicaVolume 50, Issue 5 p. 637-637 Desflurane anaesthesia increases sister chromatid exchange in human lymphocytes A. Akin, Corresponding Author A. AkinAynur Akin Erciyes University Medical Faculty Anaesthesiology and Reanimation Alpaslan mah. Kandil sok. Bezciler sitesi 3. blok No:6/11 Melikgazi Kayseri 38030 Turkey e-mail: [email protected]Search for more papers by this author A. Akin, Corresponding Author A. AkinAynur Akin Erciyes University Medical Faculty Anaesthesiology and Reanimation Alpaslan mah. Kandil sok. Bezciler sitesi 3. blok No:6/11 Melikgazi Kayseri 38030 Turkey e-mail: [email protected]Search for more papers by this author First published: 25 April 2006 https://doi.org/10.1111/j.1399-6576.2006.01010.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume50, Issue5May 2006Pages 637-637 RelatedInformation

In Vitro Mutagenicity Studies of the Antiretrovirals AZT, Didanosine, and 3TC and a Plant Antiviral Extract Secomet‐V Derived from the Trifollium Species

The plant extract Secomet-V has previously been shown by Kotwal et al. to have potent antiviral activity. It was tested for mutagenicity with the Ames gene mutation test in Salmonella and the chromosome damage (clastogenic) micronucleolus (MN) test in human lymphocytes. These tests predict long-term carcinogenesis activity of the agents tested. Secomet-V (with charcoal added) demonstrated weak clastogenic activity, but powerful mutagenic activity in the Ames test with the addition of exogenous metabolic activation. The mutagenic activity of the conventional antiretroviral drugs AZT, Didanosine (DID), and 3TC alone and in dual combinations was also assessed for the first time for Salmonella mutagenicity without any mutagenic effects. AZT, DID, and 3TC have also been tested for MN induction; DID and 3TC resulted negatively, whereas AZT was positive in a dose-related manner. The dual combinations of AZT and DID, 3TC and DID plus 3TC did not result in any additive or synergistic effect. Purification in the absence of charcoal results in a drastic reduction in extract mutagenicity, which is almost reduced completely by further ultrafiltration (cutoff <3,000 Da). This fraction, which is a mixture of molecules of less than 3,000 Da, still possesses the capability to induce sister chromatid exchanges in human lymphocytes. This could be due to residual mutagenicity or, more likely, to the slowdown of the DNA replication process. These findings open new possibilities for HIV therapy, because this antiviral activity of Secomet-V purified in the absence of charcoal and further filtered through a 3,000-Da filter is devoid of mutagenic activity and therefore safe for long-term use.

Desflurane anaesthesia increases sister chromatid exchanges in human lymphocytes

We investigated genotoxic effects of desflurane on the frequency of sister chromatid exchange (SCE) in peripheral blood lymphocytes of patients during and after anaesthesia. Fifteen female patients, ASA classification I-II, aged 26-54 years, undergoing elective surgery were enroled in this study. Anaesthesia was induced by injection of thiopental 5-7 mg/kg and fentanyl 1 microg/kg. Vecuronium 0.1 mg/kg was given to facilitate tracheal intubation. Anaesthesia was maintained with desflurane 5-6% in an oxygen/air mixture (FiO(2) 0.3). N(2)O was not used for any patient. Using a heparinized syringe, venous blood was collected in patients before anaesthesia. Additional venous blood samples were taken from all patients at 60 and 120 min after the initiation of anaesthesia. Post-operative blood samples were taken and first, third, seventh and twelfth day samples were coded. Number of SCEs per cell at 60 and 120 min were significantly higher than the number of SCEs per cell before anaesthesia. In addition, number of SCEs per cell at 1, 3 and 7th post-operative days were significantly higher than pre-operative levels (P < 0.05). There was no difference between pre-operative number of SCEs per cell and 12th post-operative day levels (P > 0.05). In the present study, because exposure to desflurane increased sister chromatid exchange in human lymphocytes in our group of patients, we conclude that this agent may be capable of producing genetic damage.

In vitro genotoxic effects of the anticancer drug gemcitabine in human lymphocytes

This research was carried out to investigate in vitro genotoxic effects of the anticancer agent gemcitabine on the induction of chromosomal aberrations and sister-chromatid exchange in human lymphocytes. Three doses of gemcitabine (0.001, 0.002 and 0.004 μg/ml) were applied to lymphocyte cultures from 15 donors. There was a significant increase in the induction of chromosome aberrations and in the occurrence of sister-chromatid exchange in these cells. In addition, gemcitabine significantly decreased the mitotic index and replicative index for all doses. Dose–response regression lines were used to compare the individual susceptibilities to gemcitabine with respect to the chromosome aberration and sister-chromatid exchange frequencies. Our results indicate that gemcitabine is able to induce both cytotoxic and genotoxic effects in human lymphocyte cultures in vitro in a dose-dependent manner.

Promutagen activation of triazine herbicides metribuzin and ametryn through Vicia faba metabolism inducing sister chromatid exchanges in human lymphocytes in vitro and in V. faba root tip meristems

The aim of our study was the induction of sister chromatid exchanges (SCE) in human lymphocytes in vitro and in root tip meristems of Vicia faba to evaluate the genotoxic effects of metribuzin and ametryn. Direct treatments of these herbicides on human lymphocytes in vitro applied 24 h after the beginning of culture did not induce SCE; however, they showed a cytotoxic effect in the cultures expressed as cellular death. On the contrary, when extracts of V. faba roots, treated for 4 h with metribuzin and ametryn (in vivo activation), were added to the lymphocyte cultures, SCEs were significantly induced with an asymptotic response. Negative responses appeared with the in vitro assays, in which metribuzin and ametryn were added directly to the 48 h lymphocyte cultures for 4 h. Nevertheless, in treatments in which the S10 metabolic mix was added, the SCE frequencies were significantly different to the control, although a concentration–response relationship was only observed with metribuzin. The results showed that both herbicides needed the V. faba metabolism to produce SCE in human lymphocyte cultures. Metribuzin and ametryn applied to V. faba root tip meristems for 4 h increased SCE frequency significantly, and a concentration–response relationship was observed with both herbicides.

Possible associations between ELF electromagnetic fields, DNA damage response processes and childhood leukaemia.

Epidemiology has shown an association between exposure to extremely low frequency (ELF) electromagnetic fields (EMF) and childhood leukaemia. The causal nature and biological basis of this association are however questionable. Studies with aneuploid cell lines raised the hypothesis that ELF EMF may act as a coleukaemogen by compromising DNA damage response to genotoxic agents such as ionising radiation. We examined this hypothesis using γ-ray-induced dicentric chromosome exchange in human lymphocytes. The results from 12 h post-γ-ray exposure to fields of 0.23, 0.47 and 0.7 mT provide no support to the hypothesis. The power of the study was sufficient to exclude an ELF enhancement of chromosomal exchange of 10–15% (2SE).

The effect of extremely low frequency electromagnetic fields (ELF-EMF) on the frequency of micronuclei and sister chromatid exchange in human lymphocytes induced by benzo( a)pyrene

The interaction of extremely low frequency electromagnetic fields (ELF-EMF) on the frequency of micronuclei (MN) and sister chromatid exchange (SCE) induced by benzo( a)pyrene (BP) in human lymphocytes was examined. A 60 Hz ELF-EMF of 0.8 mT field strength was applied either alone or with the tumor initiator, BP for 24 h. The frequencies of MN and SCE induced by BP increased in a dose-dependent manner. The co-exposure of cells to BP and 0.8 mT ELF-EMF for 24 h, followed by BP exposure for 48 h led to significant increases in the frequencies of MN and SCE compared to BP treatment for 72 h alone ( P<0.05), but no significant difference was observed between field exposed and sham exposed control cells. The obtained results suggest that low density ELF-EMF could act as an enhancer of the initiation process of BP rather than as an initiator of mutagenic effects in human lymphocytes.

Sister Chromatid Exchanges in Human Lymphocytes Exposed to Halothane and Sevoflurane In-Vitro

Sister Chromatid Exchanges in Human Lymphocytes Exposed to Halothane and Sevoflurane In-Vitro

Incomplete chromosome exchanges are not fingerprints of high LET neutrons.

A new fluorescence in situ hybridisation (FISH) technique combining whole chromosome specific DNA libraries with pan-centromeric DNA and telomeric PNA probes was introduced to investigate the induction of chromosome exchanges in human lymphocytes after exposure to low (4 Gy X rays) and high (1 Gy neutrons) linear energy transfer radiation. This combination of probes allowed accurate detection of exchange aberrations involving the painted chromosomes and an unambiguous discrimination between complete and incomplete exchanges, as well as terminal and interstitial deletions. Data obtained in the present study using combined FISH assay with telomeres detection showed no differences between two types of radiation regarding the induction of incomplete exchanges.

Evaluation of genotoxic effects of ipronidazol, Gastrogal 10R, in cultures of human peripheral blood lymphocytes

In this work, we examined the genotoxic effect of the antibiotic preparation ipronidazol (Gastrogal 10). An experiment was performed in vitro on human peripheral blood lymphocytes using the chromosome aberration and sister chromatid exchange tests. Clastogenic effects of ipronidazol were examined at three experimental concentrations (25 (g/ml, 50 (g/ml i 100 (g/ml) in eight experimental cycles. The results demonstrate that Gastrogal 10 has the ability to change the human lymphocyte kariotype, i.e. it induces numerical aberrations (aneuploidies and polyploidies), as well as chromosome gaps and breaks. Moreover, Gastrogal 10 induces a significant increase of sister chromatid exchange in human lymphocytes. The obtained results demonstrate that the examined preparation exhibits a certain genotoxic potential.

Complex chromosome exchanges induced by gamma rays in human lymphocytes: an mFISH study.

Loucas, B. D. and Cornforth, M. N. Complex Chromosome Exchanges Induced by Gamma Rays in Human Lymphocytes: An mFISH Study. Radiat. Res. 155, 660-671 (2001). Combinatorial multi-fluor fluorescence in situ hybridization (mFISH) allows the simultaneous painting of each pair of homologous chromosomes, thereby eliminating many of the difficulties previously associated with the analysis of complex rearrangements. We employed mFISH to visualize exchanges in human lymphocytes and found significant frequencies of these aberrations after gamma-ray doses of 2 and 4 Gy. At 4 Gy, roughly half of the cells contained at least one complex exchange that required anywhere from 3 to 11 initial chromosome breaks. At this dose, more than 40% of gross cytogenetic damage, as measured by the total number of exchange breakpoints, was complex in origin. Both simple and complex exchanges were found to have nonlinear dose responses, although the latter showed significantly more upward curvature. In many cases, it could be deduced that the initial breaks leading to a particular complex exchange were proximate, meaning that the resulting broken chromosome ends all must have been capable of interacting freely during the exchange process. For other complex exchanges, the rearrangement could just as well have resulted from two or more simpler exchanges that occurred sequentially. The results demonstrate the utility of mFISH in visualizing intricacies of the exchange process, but also highlight the various sources of ambiguity concerning cytogenetic analysis that remain despite the power of this approach.

Effects of donor age and contamination level of dioxins and related chemicals on frequency of sister chromatid exchanges in human lymphocytes cultured in vitro

Frequencies of sister chromatid exchanges (SCEs) of human lymphocytes in control (DMSO treated) and 7,8-benzoflavone (ANF) treated cultures were measured in 39 healthy Japanese people and examined in connection with donor age. Both the control (baseline) and ANF induced SCE rates were significantly enhanced with age and highly positive correlation was observed between them. Therefore, in vivo aging seemed to have some effects on the frequencies of SCEs in human lymphocytes cultured in vitro. Concentrations of PCDDs, PCDFs and Co-PCBs in the blood and sebum of face were determined in the same Japanese subjects. Significantly positive correlation was observed between the blood and sebum in their total TEQ levels. Hence, PCDDs, PCDFs and Co-PCBs, which have been contaminating human bodies, are considered proportionally excreted from the sebum of face or body. Their total TEQ concentrations were also meaningfully increased with donor age in the sebum of face as well as in the blood. Either the baseline or ANF induced SCE frequencies was not enhanced with the total TEQ levels in the blood. Therefore, background levels of their contamination seem not to affect the SCE rates of the lymphocytes in the control and ANF treated cultures.

Accurate detection of true incomplete exchanges in human lymphocytes exposed to neutron radiation using chromosome painting in combination with a telomeric PNA probe

Purpose : To determine the frequency of true incomplete chromosome exchanges in human lymphocytes after exposure to high-LET neutrons using chromosome painting in combination with centromeric and telomeric probes in one FISH assay. Materials and methods : Human lymphocytes were exposed in vitro to 1 MeV neutrons at a dose of 1 Gy (dose-rate 0.1Gy min -1) . Chromosome aberrations were analysed in the first mitosis after irradiation using a FISH technique that combined whole chromosome-specific DNA probes (for chromosomes 4 and 8), human pan-centromeric DNA and telomeric PNA probes. Results : The frequency of true incomplete exchanges induced by 1 MeV neutron irradiation was <5% in chromosomes 4 and 8. Comparison of the frequency of true incompleteness obtained in the present experiment with a previous study that used 4 Gy X-rays showed no striking differences between X-rays and neutrons in incomplete exchange patterns but di fferences in the spectrum of induced aberrations were detected. Simple exchanges were more frequent with X-rays, whereas complex types were significantly commoner following neutron irradiation (41 and 23% respectively). Differences were also found for complex rearrangements: both the number of these and their complexity increased after neutron-irradiation. Conclusion : The combination of chromosome painting and the detection of centromeres and telomeres enable unequivocal discrimination between incomplete and complete exchanges. The application of telomeric probes to analyse chromosome aberrations has demonstrated that true incompleteness is a rare event (~5%) following exposure to high-(neutron) as well as to low-(X-rays) LET radiation.