| 1. |
- Carlsson, Henrik, et al.
(author)
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Adductomic Screening of Hemoglobin Adducts and Monitoring of Micronuclei in School-Age Children
- 2017
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In: Chemical Research in Toxicology. - : American Chemical Society (ACS). - 0893-228X .- 1520-5010. ; 30:5, s. 1157-1167
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Journal article (peer-reviewed)abstract
- Electrophilic compounds/metabolites present in humans, originating from endogenous processes or exogenous exposure, pose a risk to health effects through their reactions with nucleophilic sites in proteins and DNA, forming adducts. Adductomic approaches are developed to screen for adducts to biomacromolecules in vivo by mass spectrometry (MS), with the aim to detect adducts corresponding to unknown exposures from electrophiles. In the present study, adductomic screening was performed using blood samples from healthy children about 12 years old (n = 51). The frequencies of micronuclei (MN) in erythrocytes in peripheral blood were monitored as a measure of genotoxic effect/genotoxic exposure. The applied adductomic approach has been reported earlier by us and is based on analysis of N-terminal valine adducts in hemoglobin (Hb) by liquid chromatography tandem mass spectrometry (LC-MS/MS). High resolution MS was introduced for refined screening of previously unknown N-terminal Hb adducts. Measured adduct levels were compared with MN frequencies using multivariate data analysis. In the 51 individuals, a total of 24 adducts (whereof 12 were previously identified) were observed and their levels quantified. Relatively large interindividual variations in adduct levels were observed. The data analysis (with partial least-squares regression) showed that as much as 60% of the MN variation could be explained by the adduct levels. This study, for the first time, applies the combination of these sensitive methods to measure the internal dose of potentially genotoxic chemicals and genotoxic effects, respectively. The results indicate that this is a valuable approach for the characterization of exposure to chemical risk factors for the genotoxic effects present in individuals of the general population.
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| 2. |
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| 3. |
- Clemedson, Cecilia, et al.
(author)
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Development of an in vitro test battery for the estimation of acute human systemic toxicity : An outline of the EDIT project. Evaluation-guided Development of New In Vitro Test Batteries
- 2002
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In: ATLA (Alternatives to Laboratory Animals). - 0261-1929. ; 30:3, s. 313-321
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Journal article (peer-reviewed)abstract
- The aim of the Evaluation-guided Development of new In Vitro Test Batteries (EDIT) multicentre programme is to establish and validate in vitro tests relevant to toxicokinetics and for organ-specific toxicity, to be incorporated into optimal test batteries for the estimation of human acute systemic toxicity. The scientific basis of EDIT is the good prediction of human acute toxicity obtained with three human cell line tests (R(2) = 0.77), in the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) programme. However, the results from the MEIC study indicated that at least two other types of in vitro test ought to be added to the existing test battery to improve the prediction of human acute systemic toxicity - to determine key kinetic events (such as biotransformation and passage through biological barriers), and to predict crucial organ-specific mechanisms not covered by the tests in the MEIC battery. The EDIT programme will be a case-by-case project, but the establishment and validation of new tests will be carried through by a common, step-wise procedure. The Scientific Committee of the EDIT programme defines the need for a specific set of toxicity or toxicokinetic data. Laboratories are then invited to perform the defined tests in order to provide the "missing" data for the EDIT reference chemicals. The results obtained will be evaluated against the MEMO (the MEIC Monograph programme) database, i.e. against human acute systemic lethal and toxicity data. The aim of the round-table discussions at the 19th Scandinavian Society for Cell Toxicology (SSCT) workshop, held in Ringsted, Denmark on 6-9 September 2001, was to identify which tests are the most important for inclusion in the MEIC battery, i.e. which types of tests the EDIT programme should focus on. It was proposed that it is important to include in vitro methods for various kinetic events, such as biotransformation, absorption in the gut, passage across the blood-brain barrier, distribution volumes, protein binding, and renal clearance/accumulation. Models for target organ toxicity were also discussed. Because several of the outlier chemicals (paracetamol, digoxin, malathion, nicotine, paraquat, atropine and potassium cyanide) in the MEIC in vivo-in vitro evaluation have a neurotoxic potential, it was proposed that the development within the EDIT target organ programme should initially be focused on the nervous system.
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| 4. |
- Gradecka-Meesters, Dobroslawa, et al.
(author)
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Assessment of the protective effects of selected dietary anticarcinogens against DNA damage and cytogenetic effects induced by benzo[a]pyrene in C57BL/6J mice
- 2011
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In: Food and Chemical Toxicology. - : Elsevier BV. - 0278-6915 .- 1873-6351. ; 49:8, s. 1674-1683
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Journal article (peer-reviewed)abstract
- The protective action in C57BL/6J mice from orally administered ellagic acid (EA), benzyl isothiocyanate (BITC), an extract of epigallocatechins (Tegreen (R)) as well as chlorophyllin (CHL) against benzo[a]pyrene (B[a]P)-induced DNA damage and cytogenetic effects was investigated. In pilot experiment the comet assay indicated protective effects for all compounds, while such activity was confined to EA and CH with respect to B[a]P-DNA adducts and micronuclei. EA and CH were chosen for the main study where the levels of DNA adducts in liver after injection of 30 mg B[a]P/kg b.w. did not differ from those found for animals exposed to B[a]P and treated with the protective substances. In leukocytes no significant protective effect of CHL was detected while a 2-fold increase of adduct concentrations was observed after co-administration of EA. In the comet assay CHL or EA caused a 3-fold decrease of SSB, and a 2-fold decrease of FPG sites in comparison to animals treated with B[a]P. CHL or EA showed a significant protective effect against B[a]P-induced MN in polychromatic erythrocytes in bone marrow. In contrast, flow cytometry measurements in peripheral blood indicated the MN frequency after treatment with CHL or EA almost twice as high as that recorded for B[a]P alone.
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| 5. |
- Gyllenhammar, Irina, et al.
(author)
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Influence of contaminated drinking water on perfluoroalkyl acid levels in human serum - A case study from Uppsala, Sweden
- 2015
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In: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 140, s. 673-683
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Journal article (peer-reviewed)abstract
- In 2012 a contamination of drinking water with perfluoroalkyl acids (PFAAs) was uncovered in the City of Uppsala, Sweden. The aim of the present study was to determine how these substances have been distributed from the contamination source through the groundwater to the drinking water and how the drinking water exposure has influenced the levels of PFAAs in humans over time. The results show that PFAA levels in groundwater measured 2012-2014 decreased downstream from the point source, although high Sigma PFAA levels (> 100 ng/L) were still found several kilometers from the point source in the Uppsala aquifer. The usage of aqueous film forming fire-fighting foams (AFFF) at a military airport in the north of the city is probably an important contamination source. Computer simulation of the distribution of PFAA-contaminated drinking water throughout the City using a hydraulic model of the pipeline network suggested that consumers in the western and southern parts of Uppsala have received most of the contaminated drinking water. PFAA levels in blood serum from 297 young women from Uppsala County, Sweden, sampled during 1996-1999 and 2008-2011 were analyzed. Significantly higher concentrations of perfluorobutane sulfonic acid (PFBS) and perfluorohexane sulfonic acid (PFHxS) were found among women who lived in districts modeled to have received contaminated drinking water compared to unaffected districts both in 1996-1999 and 2008-2011, indicating that the contamination was already present in the late 1990s. Isomer-specific analysis of PFHxS in serum showed that women in districts with contaminated drinking water also had an increased percentage of branched isomers. Our results further indicate that exposure via contaminated drinking water was the driving factor behind the earlier reported increasing temporal trends of PFBS and PFHxS in blood serum from young women in Uppsala.
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| 6. |
- Gyllenhammar, Irina, et al.
(author)
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Perfluoroalkyl acids in serum from nursing women living in an area in Sweden with drinking water contamination
- 2011
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Reports (other academic/artistic)abstract
- Under perioden 1996 till 2011 har Livsmedelsverket samlat in blodserum från förstföderskor i Uppsala län. Ett av syftena med studierna är att undersöka hur halterna av vissa persistenta organiska miljögifter (POP) förändras med tiden. I denna rapport utvärderas blodserumnivåer för 14 perfluoroalkylsyror; (PFAA) varav tio perfluoroalkylkarboxylsyror (PFCA), fyra perfluoroalkansulfonsyror (PFSA) och perfluorooktansulfonamiden FOSA , från prover tagna 1996-1999 och 2008-2011 (n=297). Syftet med studien var att utvärdera om det finns signifikanta skillnader i blodnivåer av PFAA mellan kvinnor som bor inom olika områden i Uppsala stad, för att därigenom försöka bedöma om dricksvattenexponering påverkar nivåerna av PFAA i blod. Undersökningar av PFAA i grundvattenbrunnar och dricksvatten i Uppsala har tidigare visat att kontaminerat vatten främst distribuerats till de södra delarna av Uppsala. Kontaminerade brunnar har nu tagits ur produktion. Högre blodnivåer av perflurohexansulfonsyra (PFHxS) och perfluorbutansulfonsyra (PFBS) hittades i främst det södra området av Uppsala, både 1996-1999 (ej PFBS) och 2008-2011, vilket tyder på att konsumtion av dricksvatten är en viktig källa för exponering. Halterna av PFHxS var i allmänhet högre i Uppsala stad 2008-2011 än 1996-1999, men ej bland deltagare boende utanför Uppsala. Liknande resultat sågs för PFBS, vilket antyder att kontaminerat dricksvatten ligger bakom de ökande blodhalter av substanserna som tidigare observerats i Uppsala. Vi såg också samband mellan fiskkonsumtion och ökade nivåer av PFOS från kvinnor 2008-2011, vilket indikerar att fiskkonsumtion som exponeringskälla har ökat i betydelse sen 1990-talet.
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| 7. |
- Kotova, Natalia, et al.
(author)
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(32)P-HPLC analysis of N1-(2-carboxy-2-hydroxyethyl)deoxyadenosine : A DNA adduct of the acrylamide-derived epoxide glycidamide
- 2011
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In: Toxicology Letters. - : Elsevier BV. - 0378-4274 .- 1879-3169. ; 207:1, s. 18-24
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Journal article (peer-reviewed)abstract
- Acrylamide (AA) is produced in many types of food products cooked or processed at high temperature. AA is metabolized to the epoxide glycidamide (GA), which can bind to deoxyguanosine and deoxyadenosine in DNA. The GA-derived N7-guanine and N3-adenine adducts are the only products which so far have been analysed in vivo. Because of previous excellent experience from analysis of adducts to N1-adenine, the aim of our study was to investigate if the N1-adenine adduct of GA could be used as a biomarker of AA exposure. A (32)P-postlabelling method was developed and tested (a) on DNA modified in vitro with GA, (b) on cells treated with GA and (c) on liver DNA from mice treated with M. The N1-adenine adduct of GA (analysed after conversion to N(6)-GA-deoxyadenosine-5'-monophosphate) was easily detected in DNA reacted with GA and in DNA from cells exposed to GA, but not in DNA from mice treated with AA. The reason for this is currently not clearly understood, but some of the possible contributing factors are discussed. The application of the method in other experimental conditions should be further pursued in order to solve this matter.
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| 8. |
- Kotova, Natalia, et al.
(author)
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A novel micronucleus in vitro assay utilizing human hematopoietic stem cells
- 2015
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In: Toxicology in Vitro. - : Elsevier BV. - 0887-2333 .- 1879-3177. ; 29:7, s. 1897-1905
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Journal article (peer-reviewed)abstract
- The induction of micronucleated reticulocytes in the bone marrow is a sensitive indicator of chromosomal damage. Therefore, the micronucleus assay in rodents is widely used in genotoxicity and carcinogenicity testing. A test system based on cultured human primary cells could potentially provide better prediction compared to animal tests, increasing patient safety while also implementing the 3Rs principle, i.e. replace, reduce and refine. Hereby, we describe the development of an in vitro micronucleus assay based on animal-free ex vivo culture of human red blood cells from hematopoietic stem cells. To validate the method, five clastogens with direct action, three clastogens requiring metabolic activation, four aneugenic and three non-genotoxic compounds have been tested. Also, different metabolic systems have been applied. Flow cytometry was used for detection and enumeration of micronuclei. Altogether, the results were in agreement with the published data and indicated that a sensitive and cost effective in vitro assay to assess genotoxicity with a potential to high-throughput screening has been developed.
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| 9. |
- Kotova, Natalia, 1975-
(author)
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Biomarkers for DNA damage in human biomonitoring
- 2010
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Doctoral thesis (other academic/artistic)abstract
- Genomic DNA in humans is constantly exposed to different kinds of damage. Therefore, it is desirable to implement methods for detecting and measuring of inflicted body burden. Human biomonitoring (HBM) can here be a useful tool as a link between environmental exposure and disease outcome. The present thesis aims to monitor DNA damage in humans by studies on: 1) urinary thymidine dimer (T=T) as a novel biomarker (BM) of human exposure to UV-light; 2) enumeration of variants in HPRT gene in human peripheral blood lymphocytes by developing a sensitive flow cytometric (FCM) analysis; 3) the impact of dietary habits on genomic stability in vegetarians and omnivores in terms of micronuclei (MN) induction detected by FCM. Urinary T=T was quantified by a 32P-postlabeling technique, the kinetics of T=T excretion was studied and the method was validated by delivering controlled UV-doses. The major conclusion was that the amount of urinary T=T was determined by the UV dose, and hence T=T can be used as a BM of UV exposure. Moreover, a new approach for rapid and sensitive enumeration of HPRT-variants by FCM was developed. The obtained HPRT-frequencies were comparable to those previously published by others. Finally, the FCM assay for MN enumeration was applied to study effects of dietary habits in vegetarians and omnivores. The main finding was that vegetarians had significantly lower MN frequencies compared to omnivores. In summary, the applied BMs and respective methods have high sensitivity and/or throughput possibility which are important factors considered in HBM.
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| 10. |
- Kotova, Natalia, et al.
(author)
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Differences in micronucleus frequency and acrylamide adduct levels with hemoglobin between vegetarians and non-vegetarians
- 2015
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In: European Journal of Nutrition. - : Springer Science and Business Media LLC. - 1436-6207 .- 1436-6215. ; 54:7, s. 1181-1190
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Journal article (peer-reviewed)abstract
- Nutrients and food constituents can prevent or contribute to genotoxicity. In this study, the possible influence of a vegetarian/non-vegetarian diet on genotoxic effects was investigated in 58 non-smoking healthy vegetarians (V) and non-vegetarians (NV), age 21-37 years from the Stockholm area in Sweden. Physical activity and dietary habits were similar in both groups, with the exception of the intake of meat and fish. Using flow cytometry, we determined the formation of micronuclei (MN) in transferrin-positive immature peripheral blood reticulocytes (Trf-Ret) (Total: n = 53; V: n = 27; NV: n = 26). Dietary exposure to acrylamide was measured through hemoglobin (Hb) adducts in peripheral erythrocytes (Total: n = 53; V: n = 29; NV: n = 24). Hb adducts of both acrylamide and its genotoxic metabolite glycidamide were monitored as a measure of the corresponding in vivo doses. Our data demonstrated that compared with the non-vegetarians, the vegetarians exhibited lower frequencies of MN (fMN) in the Trf-Ret (p < 0.01, Student's t test). A multivariate analysis demonstrated that there was no association between the fMN and factors such as age, sex, intake of vitamins/minerals, serum folic acid and vitamin B12 levels, physical activity, and body mass index. The mean Hb adduct levels of acrylamide and glycidamide showed no significant differences between vegetarians and non-vegetarians. Furthermore, there were no significant relationships between the adduct levels and fMN in the individuals. The ratio of the Hb adduct levels from glycidamide and acrylamide, however, showed a significant difference (p < 0.04) between the two groups. These data suggest that the vegetarian diet might be beneficial in lowering genomic instability in healthy individuals. The measured Hb adduct levels indicate that the total intake of acrylamide does not differ between the two studied groups and does not contribute to the observed difference in fMN, although an influence of the diet on the metabolic rates of acrylamide was indicated. In addition, the observed significant difference in the background fMN in the two groups demonstrated that the MN analysis method has a sensitivity applicable to the biomonitoring of human lifestyle factors.
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