Now showing items 21-40 of 348

    • On the origins and development of the (32)P-postlabelling assay for carcinogen-DNA adducts.

      Phillips, David H. (2012-11-23)
      The (32)P-postlabelling method for the analysis of carcinogen-DNA adducts originated 30years ago from Baylor College of Medicine in Houston and was the work of a team comprised of Kurt and Erica Randerath, Ramesh Gupta and Vijay Reddy. With subsequent modifications and developments, it has become a highly sensitive and versatile method for the detection of DNA adducts that has been applied in a wide range of human, animal and in vitro studies. These include monitoring human exposure to environmental and occupational carcinogens, investigating genotoxicity of chemicals, elucidating pathways of metabolic activation of carcinogens, mechanistic studies of DNA repair, analysing the genotoxicity of complex mixtures and in ecotoxicology studies. Its use has been instrumental in providing new clues to the aetiology of some cancers and in identifying a new human carcinogen.
    • Exposure to benzo[a]pyrene of Hepatic Cytochrome P450 Reductase Null (HRN) and P450 Reductase Conditional Null (RCN) mice: Detection of benzo[a]pyrene diol epoxide-DNA adducts by immunohistochemistry and 32P-postlabelling.

      Arlt, Volker M.; Poirier, Miriam C.; Sykes, Sarah E.; John, Kaarthik; Moserova, Michaela; Stiborova, Marie; Wolf, C. Roland; Henderson, Colin J.; Phillips, David H. (2012-09-03)
      Benzo[a]pyrene (BaP) is a widespread environmental carcinogen activated by cytochrome P450 (P450) enzymes. In Hepatic P450 Reductase Null (HRN) and Reductase Conditional Null (RCN) mice, P450 oxidoreductase (Por) is deleted specifically in hepatocytes, resulting in the loss of essentially all hepatic P450 function. Treatment of HRN mice with a single i.p. or oral dose of BaP (12.5 or 125mg/kg body weight) resulted in higher DNA adduct levels in liver (up to 10-fold) than in wild-type (WT) mice, indicating that hepatic P450s appear to be more important for BaP detoxification in vivo. Similar results were obtained in RCN mice. We tested whether differences between hepatocytes and non-hepatocytes in P450 activity may underlie the increased liver BaP-DNA binding in HRN mice. Cellular localisation by immunohistochemistry of BaP-DNA adducts showed that HRN mice have ample capacity for formation of BaP-DNA adducts in liver, indicating that the metabolic process does not result in the generation of a reactive species different from that formed in WT mice. However, increased protein expression of cytochrome b(5) in hepatic microsomes of HRN relative to WT mice suggests that cytochrome b(5) may modulate the P450-mediated bioactivation of BaP in HRN mice, partially substituting the function of Por.
    • NAD(P)H:quinone oxidoreductase expression in Cyp1a-knockout and CYP1A-humanized mouse lines and its effect on bioactivation of the carcinogen aristolochic acid I.

      Levova, Katerina; Moserova, Michaela; Nebert, Daniel W.; Phillips, David H.; Frei, Eva; Schmeiser, Heinz H.; Arlt, Volker M.; Stiborova, Marie (2012-12-15)
      Aristolochic acid causes a specific nephropathy (AAN), Balkan endemic nephropathy, and urothelial malignancies. Using Western blotting suitable to determine protein expression, we investigated in several transgenic mouse lines expression of NAD(P)H:quinone oxidoreductase (NQO1)-the most efficient cytosolic enzyme that reductively activates aristolochic acid I (AAI). The mouse tissues used were from previous studies [Arlt et al., Chem. Res. Toxicol. 24 (2011) 1710; Stiborova et al., Toxicol. Sci. 125 (2012) 345], in which the role of microsomal cytochrome P450 (CYP) enzymes in AAI metabolism in vivo had been determined. We found that NQO1 levels in liver, kidney and lung of Cyp1a1⁻/⁻, Cyp1a2⁻/⁻ and Cyp1a1/1a2⁻/⁻ knockout mouse lines, as well as in two CYP1A-humanized mouse lines harboring functional human CYP1A1 and CYP1A2 and lacking the mouse Cyp1a1/1a2 orthologs, differed from NQO1 levels in wild-type mice. NQO1 protein and enzymic activity were induced in hepatic and renal cytosolic fractions isolated from AAI-pretreated mice, compared with those in untreated mice. Furthermore, this increase in hepatic NQO1 enzyme activity was associated with bioactivation of AAI and elevated AAI-DNA adduct levels in ex vivo incubations of cytosolic fractions with DNA and AAI. In conclusion, AAI appears to increase its own metabolic activation by inducing NQO1, thereby enhancing its own genotoxic potential.
    • Polycyclic aromatic hydrocarbons as skin carcinogens: comparison of benzo[a]pyrene, dibenzo[def,p]chrysene and three environmental mixtures in the FVB/N mouse.

      Siddens, Lisbeth K.; Larkin, Andrew; Krueger, Sharon K.; Bradfield, Christopher A.; Waters, Katrina M.; Tilton, Susan C.; Pereira, Cliff B.; Löhr, Christiane V.; Arlt, Volker M.; Phillips, David H.; et al. (2012-11-01)
      The polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (BaP), was compared to dibenzo[def,p]chrysene (DBC) and combinations of three environmental PAH mixtures (coal tar, diesel particulate and cigarette smoke condensate) using a two stage, FVB/N mouse skin tumor model. DBC (4nmol) was most potent, reaching 100% tumor incidence with a shorter latency to tumor formation, less than 20 weeks of 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion compared to all other treatments. Multiplicity was 4 times greater than BaP (400 nmol). Both PAHs produced primarily papillomas followed by squamous cell carcinoma and carcinoma in situ. Diesel particulate extract (1 mg SRM 1650b; mix 1) did not differ from toluene controls and failed to elicit a carcinogenic response. Addition of coal tar extract (1 mg SRM 1597a; mix 2) produced a response similar to BaP. Further addition of 2 mg of cigarette smoke condensate (mix 3) did not alter the response with mix 2. PAH-DNA adducts measured in epidermis 12 h post initiation and analyzed by ³²P post-labeling, did not correlate with tumor incidence. PAH-dependent alteration in transcriptome of skin 12 h post initiation was assessed by microarray. Principal component analysis (sum of all treatments) of the 922 significantly altered genes (p<0.05), showed DBC and BaP to cluster distinct from PAH mixtures and each other. BaP and mixtures up-regulated phase 1 and phase 2 metabolizing enzymes while DBC did not. The carcinogenicity with DBC and two of the mixtures was much greater than would be predicted based on published Relative Potency Factors (RPFs).
    • Variation in PAH-related DNA adduct levels among non-smokers: The role of multiple genetic polymorphisms and nucleotide excision repair phenotype.

      Etemadi, Arash; Islami, Farhad; Phillips, David H.; Godschalk, Roger; Golozar, Asieh; Kamangar, Farin; Malekshah, Akbar Fazel-Tabar; Pourshams, Akram; Elahi, Seerat; Ghojaghi, Farhad; et al. (2012-11-23)
      Polycyclic aromatic hydrocarbons (PAHs) likely play a role in many cancers even in never-smokers. We tried to find a model to explain the relationship between variation in PAH-related DNA adduct levels among people with similar exposures, multiple genetic polymorphisms in genes related to metabolic and repair pathways, and nucleotide excision repair (NER) capacity. In 111 randomly selected female never-smokers from the Golestan Cohort Study in Iran, we evaluated 21 SNPs in 14 genes related to xenobiotic metabolism and 12 SNPs in eight DNA repair genes. NER capacity was evaluated by a modified comet assay, and aromatic DNA adduct levels were measured in blood by32P-postlabeling. Multivariable regression models were compared by Akaike's information criterion (AIC). Aromatic DNA adduct levels ranged between 1.7 and 18.6 per 10(8) nucleotides (mean: 5.8 ± 3.1). DNA adduct level was significantly lower in homozygotes for NAT2 slow alleles and ERCC5 non-risk-allele genotype, and was higher in the MPO homozygote risk-allele genotype. The sum of risk alleles in these genes significantly correlated with the log-adduct level (r = 0.4, p < 0.001). Compared with the environmental model, adding Phase I SNPs and NER capacity provided the best fit, and could explain 17% more of the variation in adduct levels. NER capacity was affected by polymorphisms in the MTHFR and ERCC1 genes. Female non-smokers in this population had PAH-related DNA adduct levels three to four times higher than smokers and occupationally-exposed groups in previous studies, with large inter-individual variation which could best be explained by a combination of Phase I genes and NER capacity.
    • DNA and protein adducts in human tissues resulting from exposure to tobacco smoke.

      Phillips, David H.; Venitt, Stan (2012-12-15)
      Tobacco smoke contains a variety of genotoxic carcinogens that form adducts with DNA and protein in the tissues of smokers. Not only are these biochemical events relevant to the carcinogenic process, but the detection of adducts provides a means of monitoring exposure to tobacco smoke. Characterization of smoking-related adducts has shed light on the mechanisms of smoking-related diseases and many different types of smoking-derived DNA and protein adducts have been identified. Such approaches also reveal the potential harm of environmental tobacco smoke (ETS) to nonsmokers, infants and children. Because the majority of tobacco-smoke carcinogens are not exclusive to this source of exposure, studies comparing smokers and nonsmokers may be confounded by other environmental sources. Nevertheless, certain DNA and protein adducts have been validated as biomarkers of exposure to tobacco smoke, with continuing applications in the study of ETS exposures, cancer prevention and tobacco product legislation. Our article is a review of the literature on smoking-related adducts in human tissues published since 2002.
    • Human and Methodological Sources of Variability in the Measurement of Urinary 8-Oxo-7,8-dihydro-2'-deoxyguanosine.

      Barregard, Lars; Moller, Peter; Henriksen, Trine; Mistry, Vilas; Koppen, Gudrun; Rossner, Pavel; Sram, Radim J.; Weimann, Allan; Poulsen, Henrik E.; Nataf, Robert; et al. (2013-01-31)
      Abstract Aims: Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical- and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject- and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (r(p) 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine- or SG-adjusted first morning samples are recommended.
    • Validation of the nucleotide excision repair comet assay on cryopreserved PBMCs to measure inter-individual variation in DNA repair capacity.

      Allione, Alessandra; Russo, Alessia; Ricceri, Fulvio; Vande Loock, Kim; Guarrera, Simonetta; Voglino, Floriana; Kirsch-Volders, Micheline; Matullo, Giuseppe (2013-01)
      Inter-individual susceptibility to mutagens/carcinogens can be assessed by either genotyping DNA repair genes in different pathways or phenotyping DNA repair capacity (DRC) at the molecular or cellular level. Due to the large number of known DNA repair genes, and the interactions between repair pathways, phenotyping is becoming the preferred approach to measure DRC, and reliable assays are therefore increasingly needed. The use of a cellular phenotype comet assay for the nucleotide excision repair (NER) pathway using benzo[a]pyrene diol epoxide (BPDE) has been described in previous papers, but no thorough evaluation of its applicability in large genotype-phenotype studies has been presented. Our aim was to evaluate the possibility of using cryopreserved instead of fresh peripheral blood mononuclear cells (PBMCs) to evaluate intra- and inter-assay variation, and inter-individual variation, for the aphidicolin (APC)-block NER comet assay. Moreover, we measured the variation for the designated internal standard (K562 erythroleukaemia cell line) and we evaluated the feasibility to use lymphoblastoid cell lines (LCLs) as surrogate of PBMCs. Our results showed a low intra-assay [coefficient of variation (CV) 19.9%] and inter-assay (CV 32.3%) variation, with a good inter-individual variation (122 subjects, mean ± standard deviation 7.38 ± 4.99; range 0.66-26.14; CV 67.63%). A significant correlation between results derived from cryopreserved and fresh PBMCs from the same individuals was found (10 subjects, r = 0.62, P = 0.05). Results from LCLs and cryopreserved PBMCs from the same subjects showed an inverse significant correlation (10 subjects, r = -0.712, P = 0.02). K562 cells as internal standard showed low intra-assay variation. In the present study the APC-block NER comet assay on cryopreserved PBMCs seemed to be a reliable method to measure DRC variation in epidemiological studies; LCLs were not a good surrogate in this assay.
    • Quantification of ultraviolet radiation-induced DNA damage in the urine of Swedish adults and children following exposure to sunlight.

      Liljendahl, Tove Sandberg; Kotova, Natalia; Segerback, Dan (2012-11)
      DNA damage following exposure to ultraviolet radiation (UVR) is important in skin cancer development. The predominant photoproduct, cyclobutane thymine dimer (T=T), is repaired and excreted in the urine, where it provides a biomarker of exposure.
    • The effects of hemodialysis treatment on the level of DNA strand breaks and oxidative DNA lesions measured by the comet assay.

      Ersson, Clara; Odar-Cederlof, Ingegerd; Fehrman-Ekholm, Ingela; Möller, Lennart (2012-12-20)
      Hemodialysis patients have a higher risk for oxidative stress-related complications, such as cardiovascular disease and cancer. The increased level of oxidative stress is due to several factors, e.g., the hemodialysis treatment itself and the uremic state. In the present study, the effects of dialysis treatment on the level of DNA breaks and oxidative DNA lesions in mononuclear cells were measured with the comet assay. Factors possibly affecting DNA damage (reported as % DNA in tail) such as the duration of dialysis, time since last dialysis session, years of dialysis treatment, nutritional status (measured as protein catabolic rate), age, and diabetes were also investigated. The levels of DNA breaks (13.6 ± 4.7 before dialysis) and oxidative DNA lesions (7.9 ± 4.8 before dialysis) were significantly higher in dialysis patients (n = 31) compared to the levels of DNA breaks (5.8 ± 1.1) and oxidative DNA lesions (3.4 ± 1.7) in 10 healthy controls (P < 0.001). A decrease of DNA breaks was observed after dialysis (P = 0.038), and the level of oxidative DNA lesions was higher when the time between two treatment sessions were 68 hours compared to 44 hours (P < 0.001). Older subjects had a higher level of DNA breaks (P = 0.003), a good nutritional status predicted a lower level of DNA breaks (P < 0.001), and the duration of the dialysis session was inversely correlated with oxidative DNA lesions (P = 0.014). Diabetes or years of dialysis treatment did not affect DNA damage. The observations in the present study suggest that accumulation of uremic toxins induce DNA damage. The hemodialysis treatment seems to change the DNA damage.
    • Rotating night shift work and mammographic density.

      Peplonska, Beata; Bukowska, Agnieszka; Sobala, Wojciech; Reszka, Edyta; Gromadzinska, Jolanta; Wasowicz, Wojciech; Lie, Jenny Anne; Kjuus, Helge; Ursin, Giske (2012-07)
      An increased risk of breast cancer has been observed in night shift workers. Exposure to artificial light at night and disruption of the endogenous circadian rhythm with suppression of the melatonin synthesis have been suggested mechanisms. We investigated the hypothesis that rotating night shift work is associated with mammographic density.
    • Detection of acetaldehyde derived N(2)-ethyl-2'-deoxyguanosine in human leukocyte DNA following alcohol consumption.

      Singh, Rajinder; Gromadzinska, Jolanta; Mistry, Yogita; Cordell, Rebecca; Juren, Tina; Segerback, Dan; Farmer, Peter B. (2012-09-01)
      Epidemiological studies have shown an association between alcohol (ethanol) consumption and increased cancer risk. The effect of alcohol consumption on the levels and persistence of N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) formed by acetaldehyde, the oxidative metabolite of ethanol, in human leukocyte DNA was investigated. DNA was isolated from venous blood samples obtained from 30 male non-smoking individuals before consumption of alcohol (0h) and subsequently at 3-5h following the consumption of 150mL of vodka (containing 42% pure ethanol). Additional samples were collected 24h and 48h post-alcohol consumption. The levels of N(2)-ethyl-2'-deoxyguanosine (N(2)-ethyl-dG) in the DNA were determined following reduction of N(2)-ethylidene-dG with sodium cyanoborohydride using a liquid chromatography-tandem mass spectrometry selected reaction monitoring method. A slight time-dependent trend showing an increase and decrease in the levels of N(2)-ethyl-dG was observed following consumption of alcohol compared to time 0h, however, the differences were not statistically significant. The average levels of N(2)-ethyl-dG observed at 0h, 3-5h, 24h and 48h time points following ingestion of alcohol were 34.6±21.9, 35.1±21.0, 36.8±20.7 and 35.6±21.1 per 10(8) 2'-deoxynucleosides, respectively. In conclusion, alcohol consumption that could be encountered under social drinking conditions, does not significantly alter the levels of the acetaldehyde derived DNA adduct, N(2)-ethyl-dG in human leukocyte DNA from healthy individuals.
    • Inter-laboratory variation in DNA damage using a standard comet assay protocol.

      Forchhammer, Lykke; Ersson, Clara; Loft, Steffen; Moller, Lennart; Godschalk, Roger W. L.; van Schooten, Frederik J.; Jones, George D. D.; Higgins, Jennifer A.; Cooke, Marcus; Mistry, Vilas; et al. (2012-07-27)
      There are substantial inter-laboratory variations in the levels of DNA damage measured by the comet assay. The aim of this study was to investigate whether adherence to a standard comet assay protocol would reduce inter-laboratory variation in reported values of DNA damage. Fourteen laboratories determined the baseline level of DNA strand breaks (SBs)/alkaline labile sites and formamidopyrimidine DNA glycosylase (FPG)-sensitive sites in coded samples of mononuclear blood cells (MNBCs) from healthy volunteers. There were technical problems in seven laboratories in adopting the standard protocol, which were not related to the level of experience. Therefore, the inter-laboratory variation in DNA damage was only analysed using the results from laboratories that had obtained complete data with the standard comet assay protocol. This analysis showed that the differences between reported levels of DNA SBs/alkaline labile sites in MNBCs were not reduced by applying the standard assay protocol as compared with the laboratory's own protocol. There was large inter-laboratory variation in FPG-sensitive sites by the laboratory-specific protocol and the variation was reduced when the samples were analysed by the standard protocol. The SBs and FPG-sensitive sites were measured in the same experiment, indicating that the large spread in the latter lesions was the main reason for the reduced inter-laboratory variation. However, it remains worrying that half of the participating laboratories obtained poor results using the standard procedure. This study indicates that future comet assay validation trials should take steps to evaluate the implementation of standard procedures in participating laboratories.
    • International Validation of the Comet Assay and a Human Intervention Study.

      Ersson, Clara (Karolinska Institutet, 2011, 2011)
      The comet assay is an established, sensitive method extensively used in biomonitoring studies. The methods' advantages include; a) only a small cell sample is required, b) possibility to measure damage in practically any cell type, c) ability to measure heterogeneity in response within a cell population, d) relatively fast and economical procedure, and e) various applications of the method, which allow measurement of a range of different DNA lesions as well as DNA repair. Several guidelines for the comet assay have been published, but no standardised protocol exists as yet. There are considerable differences between the protocols used by different research groups, which negatively affect inter-laboratory comparisons of results. Several experts in the field have highlighted the need for multi-laboratory, international validation studies, to assess intra- and inter-laboratory reproducibility and to investigate sources of variability in the results. The papers in this thesis can be divided into two parts; one part that deals with international inter-laboratory validation studies and methodological aspects of the comet assay (paper I-III), and the other part covers a human intervention study with antioxidant capsules consisting of many different antioxidants in low doses for which the comet assay has been applied (paper IV-V). The inter-laboratory validation trials in papers I-II indicate that the participants can detect dose-responses of both DNA breaks and oxidatively damaged DNA in coded cells, but that there is a large inter-laboratory variation in the reported values. This variation can in part be explained by differences in comet assay protocols and in image analysis. The inter-laboratory variation was decreased, but not completely removed, by calibration with ionising radiation. In paper III we verified that several protocol steps significantly affected the outcome of the comet assay, including a) density of the agarose gel, b) extent of enzymatic incubation, c) duration of alkaline treatment, and d) time of electrophoresis, as well as the strength of the electric field applied. In a parallel placebo-controlled, double-blind intervention study, overweight middle-aged men were supplemented for six weeks with a multivitamin supplement consisting of a range of antioxidants in doses resembling those achieved by a healthy diet (paper IV-V). In spite of elevated levels of seven out of eight measured antioxidants in the blood, the intervention did not affect the level of oxidation of lipids or DNA. Many intervention studies with good design report similar null findings. It is preferred to consume antioxidants through a healthy diet, and dietary supplements are not recommended for cancer prevention.
    • Lymphoma; Pre-diagnostic Blood Markers and Occupational and Environmental Exposures.

      Saberi Hosnijeh, Fatemeh (Utrecht University, 2012, 2012)
      The overall aim of this thesis is to study the possible perturbations of the immune system by occupational and environmental risk factors of Non-Hodgkin lymphoma (NHL) and to study these changes in relation to NHL risk in prospective cohorts. In the first section, we validated the application of single blood cytokine measurements as a biomarker of immune status in prospective epidemiological studies. Potential utility of stored blood samples of a prospective cohort was evaluated by the effect of different blood sample types and freeze-thaw cycles on cytokine levels. This study showed strong correlations between different sample types. Moreover, freeze-thaw cycles did not markedly change cytokine levels. The intra-individual variance in cytokine levels was much smaller than the inter-individual variance which supports the notion that a single cytokine measurement can be used to characterize an individual's immune profile prospectively. Subsequently, we assessed the levels of these cytokines in pre-diagnostic blood samples of participants of a case–control study nested into the Italian European Prospective Investigation into Cancer and Nutrition cohort (EPIC) and determined their association with the risk of developing NHL. The results suggest a possible association between increased/decreased plasma levels of interleukin (IL)2, inter-cellular adhesion molecule, interferon gamma (IFN-γ), and tumor necrosis factor alpha with NHL risk. In the second section, we studied the possible immunological effects of two possibly lymphomagens: an occupational exposure (i.e. 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD)) and an environmental risk factor (i.e. obesity). We assessed a broad range of immunologic parameters directed towards detecting abnormalities in the humoral and cellular arms of the immune system among workers exposed to chlorophenoxy herbicides, chlorophenols and dioxins in particular TCDD. These studies showed that plasma TCDD levels were not associated with markers of humoral immunity with the possible exception of a decrease in complement factor 4 levels. Most lymphocyte subsets, in particular the B cell compartment, showed a decrease in cell counts with increasing levels of TCDD. Moreover, blood levels of most cytokines, chemokines and growth factors had a negative association with TCDD levels with a formal statistical significance for fractalkine, transforming growth factor alpha and fibroblast growth factor 2. These changes were independent from the changes in blood cell counts. Our findings support the notion that dioxin exposure can have an adverse impact on the immune system and likely suppresses the immune system. To identify immunologic hallmarks of obesity, we measured plasma levels of cytokines in pre-diagnostic blood samples of participants of a case-control study nested in the Italian EPIC cohort. IL8, IL10, IFN-γ, and interferon-induced protein 10 (IP10) were related to obesity. However, the set of obesity predictors (IL8, IL10, IFN-γ, IP10) were not associated with future NHL risk. Our studies support that subtle perturbations in the immune system may precede lymphoma development and suggest that B cell activation, chronic inflammation and/or an unbalance in Th1/Th2-responses are likely important phenomena in lymphomagenesis. Although, possible occupational and environmental risk factors of NHL influence the immune system they did not pertubate immune markers shown to be associated with future NHL risk.
    • Oxidative stress and DNA damage caused by the urban air pollutant 3-NBA and its isomer 2-NBA in human lung cells analyzed with three independent methods.

      Nagy, Eszter; Johansson, Clara; Zeisig, Magnus; Moller, Lennart (2005-11-15)
      The air pollutant 3-nitrobenzanthrone (3-NBA), emitted in diesel exhaust, is a potent mutagen and genotoxin. 3-NBA can isomerise to 2-nitrobenzanthrone (2-NBA), which can become more than 70-fold higher in concentration in ambient air. In this study, three independent methods have been employed to evaluate the oxidative stress and genotoxicity of 2-NBA compared to 3-NBA in the human A549 lung cell line. HPLC-EC/UV was applied for measurements of oxidative damage in the form of 8-oxo-2'-deoxyguanosine (8-oxodG), (32)P-HPLC for measurements of lipophilic DNA-adducts, and the Comet assay to measure a variety of DNA lesions, including oxidative stress. No significant oxidative damage from either isomer was found regarding formation of 8-oxodG analysed using HPLC-EC/UV. However, the Comet assay (with FPG-treatment), which is more sensitive and detects more types of damages compared to HPLC-EC/UV, showed a significant effect from both 3-NBA and 2-NBA. (32)P-HPLC revealed a strong DNA-adduct formation from both 3-NBA and 2-NBA, and also a significant difference between both isomers compared to negative control. These results clearly show that 2-NBA has a genotoxic potential. Even if the DNA-adduct forming capacity and the amount of DNA lesions measured with the (32)P-HPLC and Comet assay is about one third of 3-NBA, the high abundance of 2-NBA in ambient air calls for further investigation and evaluation of its health hazard.
    • Stability and reproducibility of simultaneously detected plasma and serum cytokine levels in asymptomatic subjects.

      Saberi Hosnijeh, Fatemeh; Krop, Esmeralda J. M.; Portengen, Lutzen; Rabkin, Charles S.; Linseisen, Jakob; Vineis, Paolo; Vermeulen, Roel (2010-03)
      Blood levels of cyto- and chemokines might reflect immune deregulations which might be related to lymphomagenesis. Potential utility of stored blood samples of a prospective cohort was evaluated by the effect of different blood sample types and freeze-thaw cycles on analyte levels. Bead-based immunoassays were performed on two fresh samples (serum, citrate and heparin plasma) of 10 asymptomatic adults collected 14 days apart and on aliquots of the first samples which were put through one to three freeze-thaw cycles to measure 11 cytokines, four chemokines and two adhesion molecules. Median coefficients of variation (CVs) of the measured analytes were 20%, 24% and 32% in serum, citrate and heparin plasma, respectively. Strong correlations (rank correlation coefficient 0.74-0.98) were observed between sample types, although small differences in analyte levels were observed for most analytes. Freeze-thaw cycles did not markedly change analyte levels. Our study supports the use of this assay among asymptomatic subjects in epidemiological studies.
    • Modszer osszehasonlito vizsgalatok policiklusos aromas szenhidrogen (PAH) modellvegyuletek DNS adduktjainak meghatarozasara. (in Hungarian)

      Kovacs, Katalin; Panagiotis, Georgiadis; Stella, Kaila; Anna, Livia; Schoket, Bernadette; Soterios, Kyrtopoulos (2011-11)
    • Plasma cytokines and future risk of non-Hodgkin lymphoma (NHL): a case-control study nested in the Italian European Prospective Investigation into Cancer and Nutrition.

      Saberi Hosnijeh, Fatemeh; Krop, Esmeralda J.M.; Scoccianti, Chiara; Krogh, Vittorio; Palli, Domenico; Panico, Salvatore; Tumino, Rosario; Sacredote, Carlotta; Nawroly, Niga; Portengen, Lutzen; et al. (2010-06)
      Recently, biological markers related to the immune system such as cytokines have been studied to further understand the etiology of non-Hodgkin Lymphoma (NHL). However, to date, there are no studies that have studied cytokine levels prospectively in relation to NHL risk in the general population.
    • Immunologic profile of excessive body weight.

      Azar Sharabiani, Mansour Taghavi; Vermeulen, Roel; Scoccianti, Chiara; Hosnijeh, Fatemeh Saberi; Minelli, Liliana; Sacerdote, Carlotta; Palli, Domenico; Krogh, Vittorio; Tumino, Rosario; Chiodini, Paolo; et al. (2011-05)
      The purpose of this paper is to identify immunologic hallmarks of excessive bodyweight. The analysis is based on 176 adults (106 women, 70 men) who participated in a nested case-control study in Italy. All participants were healthy at the time of blood collection and aged between 36 and 75 years. We employed multivariate analysis of variance and a nonparametric Bayesian additive regression tree approach along with a receiver operating characteristic (ROC) curve analysis to determine the immunologic signature of excessive body weight (i.e., obesity and overweight). Interleukin 8 (IL-8), IL-10, interferon γ, and inducible protein 10 were shown to be predictive of excessive body weight with an area under the ROC curve of 71% (p < 0.0002). We propose that by using this profile-based approach to define immunologic signatures, it might be possible to identify unique immunologic hallmarks of specific types of obesity.