Perinatal High-Fat Diet Influences Ozone-Induced Responses on Pulmonary Oxidant Status and the Molecular Control of Mitophagy in Female Rat Offspring

Previous research has shown that a perinatal obesogenic, high-fat diet (HFD) is able to exacerbate ozone-induced adverse effects on lung function, injury, and inflammation in offspring, and it has been suggested that mitochondrial dysfunction is implicated herein. The aim of this study was to investigate whether a perinatal obesogenic HFD affects ozone-induced changes in offspring pulmonary oxidant status and the molecular control of mitochondrial function. For this purpose, female Long-Evans rats were fed a control diet or HFD before and during gestation, and during lactation, after which the offspring were acutely exposed to filtered air or ozone at a young-adult age (forty days). Directly following this exposure, the offspring lungs were examined for markers related to oxidative stress; oxidative phosphorylation; and mitochondrial fusion, fission, biogenesis, and mitophagy. Acute ozone exposure significantly increased pulmonary oxidant status and upregulated the molecular machinery that controls receptor-mediated mitophagy. In female offspring, a perinatal HFD exacerbated these responses, whereas in male offspring, responses were similar for both diet groups. The expression of the genes and proteins involved in oxidative phosphorylation and mitochondrial biogenesis, fusion, and fission was not affected by ozone exposure or perinatal HFD. These findings suggest that a perinatal HFD influences ozone-induced responses on pulmonary oxidant status and the molecular control of mitophagy in female rat offspring.

The Ageing Brain: Effects on DNA Repair and DNA Methylation in Mice

Base excision repair (BER) may become less effective with ageing resulting in accumulation of DNA lesions, genome instability and altered gene expression that contribute to age-related degenerative diseases. The brain is particularly vulnerable to the accumulation of DNA lesions; hence, proper functioning of DNA repair mechanisms is important for neuronal survival. Although the mechanism of age-related decline in DNA repair capacity is unknown, growing evidence suggests that epigenetic events (e.g., DNA methylation) contribute to the ageing process and may be functionally important through the regulation of the expression of DNA repair genes. We hypothesize that epigenetic mechanisms are involved in mediating the age-related decline in BER in the brain. Brains from male mice were isolated at 3-32 months of age. Pyrosequencing analyses revealed significantly increased Ogg1 methylation with ageing, which correlated inversely with Ogg1 expression. The reduced Ogg1 expression correlated with enhanced expression of methyl-CpG binding protein 2 and ten-eleven translocation enzyme 2. A significant inverse correlation between Neil1 methylation at CpG-site2 and expression was also observed. BER activity was significantly reduced and associated with increased 8-oxo-7,8-dihydro-2'-deoxyguanosine levels. These data indicate that Ogg1 and Neil1 expression can be epigenetically regulated, which may mediate the effects of ageing on DNA repair in the brain.

Maternal intake of quercetin during gestation alters ex vivo benzo[a]pyrene metabolism and DNA adduct formation in adult offspring

Variation in xenobiotic metabolism cannot entirely be explained by genetic diversity in metabolic enzymes. We suggest that maternal diet during gestation can contribute to variation in metabolism by creating an in utero environment that shapes the offspring's defence against chemical carcinogens. Therefore, pregnant mice were supplemented with the natural aryl hydrocarbon receptor (AhR) agonist quercetin (1 mmol quercetin/kg feed) until delivery. Next, it was investigated whether the adult offspring at the age of 12 weeks had altered biotransformation of the environmental pollutant benzo[a]pyrene (B[a]P). In utero quercetin exposure resulted in significantly enhanced gene expression of Cyp1a1, Cyp1b1, Nqo1 and Ugt1a6 in liver of foetuses at Day 14.5 of gestation. Despite cessation of supplementation after delivery, altered gene expression persisted into adulthood, but in a tissue- and gender-dependent manner. Expression of Phase I enzymes (Cyp1a1 and Cyp1b1) was up-regulated in the liver of adult female mice in utero exposed to quercetin, whereas expression of Phase II enzymes (Gstp1, Nqo1 and Ugt1a6) was predominantly enhanced in the lung tissue of female mice. Epigenetic mechanisms may contribute to this adapted gene expression, as the repetitive elements (SINEB1) were hypomethylated in liver of female mice prenatally exposed to quercetin. Studies on ex vivo metabolism of B[a]P by lung and liver microsomes showed that the amount of B[a]P-9,10-dehydrodiol, B[a]P-7,8-dihydrodiol and 3-hydroxy-B[a]P did not change, but the amount of unmetabolised B[a]P was significantly lower after incubation with lung microsomes from offspring that received quercetin during gestation. Moreover, ex vivo B[a]P-induced DNA adduct formation was significantly lower for liver microsomes of offspring that were exposed to quercetin during gestation. These results suggest that prenatal diet leads to persistent alterations in Phase I and II enzymes of adult mice and may affect cancer risk.

Evaluation of benzo(a)pyrene-induced gene mutations in male germ cells

Polycyclic aromatic hydrocarbons (PAHs) are mutagenic in somatic cells, whereas it remains unclear whether PAHs induce mutations in male germ cells, subsequently increasing health risks in offspring. Although results from the classical specific locus test are negative or inconclusive, recent studies with environmentally exposed animals suggest that PAHs are mutagenic in sperm cells. Therefore, we studied whether benzo(a)pyrene (B[a]P) was able to induce gene mutations in testis and sperm cells of wild-type (Wt) and Xpc(-/-) mice containing the pUR288 lacZ reporter gene. Mice were exposed to B[a]P (13 mg/kg body weight, three times per week) during 1, 4, or 6 weeks and sacrificed 6 weeks after the final exposure to obtain mutations in sperm derived from B[a]P-exposed spermatogonial stem cells. The lacZ gene mutation assay was used to assess mutant frequencies in spleen, testis, and mature sperm, and (32)P-postlabeling was used for the detection of DNA adducts in testis. Successful exposure was confirmed by a dose-related higher mutant frequency in spleen of Xpc(-/-) mice as compared with Wt mice. Mutant frequencies were also increased in all ethyl nitrosourea-exposed samples, which were used as positive control. Although B[a]P-related DNA adducts were detected in testis, mutant frequencies were not increased. On the other hand, B[a]P increased mutant frequencies in sperm of Wt mice, but not in Xpc(-/-) mice, after 6 weeks exposure. Therefore, we conclude that B[a]P can induce gene mutations in spermatogonial cells of mice, but it remains to be elucidated whether these mutations can be transmitted to offspring.

Global gene expression analysis reveals differences in cellular responses to hydroxyl- and superoxide anion radical-induced oxidative stress in caco-2 cells

Reactive oxygen species-induced oxidative stress in the colon is involved in inflammatory bowel diseases and suggested to be associated with colorectal cancer risk. However, our insight in molecular responses to different oxygen radicals is still fragmentary. Therefore, we studied global gene expression by an extensive time series (0.08, 0.25, 0.5, 1, 2, 4, 8, 16, or 24 h) analyses in human colon cancer (caco-2) cells after exposure to H(2)O(2) or the superoxide anion donor menadione. Differences in gene expression were investigated by hybridization on two-color microarrays against nonexposed time-matched control cells. Next to gene expression, correlations with related phenotypic markers (8-oxodG levels and cell cycle arrest) were investigated. Gene expression analysis resulted in 1404 differentially expressed genes upon H(2)O(2) challenge and 979 genes after menadione treatment. Further analysis of gene expression data revealed how these oxidant responses can be discriminated. Time-dependent coregulated genes immediately showed a pulse-like response to H(2)O(2), while the menadione-induced expression is not restored over 24 h. Pathway analyses demonstrated that H(2)O(2) immediately influences pathways involved in the immune function, while menadione constantly regulated cell cycle-related pathways Altogether, this study offers a novel and detailed insight in the similarities and differences of the time-dependent oxidative stress responses induced by the oxidants H(2)O(2) and menadione and show that these can be discriminated regarding their modulation of particular colon carcinogenesis-related mechanisms.

Witch hazel (Hamamelis virginiana) fractions and the importance of gallate moieties--electron transfer capacities in their antitumoral properties

Witch hazel (Hamamelis virginia) extracts are used in traditional medicine. They are particularly rich in gallate esters included in proanthocyanidins, hydrolyzable tannins (galloylated sugars), and methyl gallate. This study examines the response of human colon cancer cells to treatment with fractions obtained from a witch hazel polyphenolic extract. The results are compared with those obtained previously with homologous fractions from grape (less galloylated) and pine (nongalloylated). Witch hazel fractions were the most efficient in inhibiting cell proliferation in HT29 and HCT116 human colon cancer cell lines, which clearly shows that the more galloylated the fractions, the more effective they were at inhibiting proliferation of colon cancer cells. Witch hazel fractions were, in addition, more potent in arresting the cell cycle at the S phase and inducing apoptosis; they also induced a significant percentage of necrosis. Interestingly, the apoptosis and cell cycle arrest effects induced were proportional to their galloylation. Moreover, witch hazel fractions with a high degree of galloylation were also the most effective as scavengers of both hydroxyl and superoxide radicals and in protecting against DNA damage triggered by the hydroxyl radical system. These findings provide a better understanding of the structure-bioactivity relationships of polyphenolics, which should be of assistance in choosing an appropriate source and preparing a rational design for formulations of plant polyphenols in nutritional supplements.

Interactions between polycyclic aromatic hydrocarbons in binary mixtures: effects on gene expression and DNA adduct formation in precision-cut rat liver slices

Although exposure to polycyclic aromatic hydrocarbons (PAHs) occurs mostly through mixtures, hazard and risk assessment are mostly based on the effects caused by individual compounds. The objective of the current study was to investigate whether interactions between PAHs occur, focusing on gene expression (as measured by cDNA microarrays) and DNA adduct formation. The effects of benzo[a]pyrene or dibenzo[a,h]anthracene (DB[a,h]A) alone and in binary mixtures with another PAH (DB[a,h]A, benzo[b]fluoranthene, fluoranthene or dibenzo[a,l]pyrene) were investigated using precision-cut rat liver slices. All compounds significantly modulated the expression of several genes, but overlap between genes affected by the mixture and by the individual compounds was relatively small. All mixtures showed an antagonistic response on total gene expression profiles. Moreover, at the level of individual genes, mostly antagonism was evident, with additivity and synergism observed for only a few genes. As far as DNA adduct formation is concerned, the binary mixtures generally caused antagonism. The effects in liver slices suggest a lower carcinogenic potency of PAH mixtures than estimated based on additivity of individual compounds.

Influence of TCDD and natural Ah receptor agonists on benzo[a]pyrene-DNA adduct formation in the Caco-2 human colon cell line

Several compounds originating from cruciferous vegetables and citrus fruits bind to and activate the aryl hydrocarbon receptor (AhR). This receptor plays an important role in the toxicity of the known tumour promoter and potent AhR-agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, vegetables and fruits are generally considered as healthy. Therefore, besides the AhR activation, the natural AhR agonists (NAhRAs) are assumed to show other health-concerning effects. AhR activation induces several cytochrome P450 phase I enzymes involved, e.g. in the bioactivation of carcinogenic polycyclic aromatic hydrocarbons, like benzo[a]pyrene (BaP), and may as such stimulate DNA adduct formation of those compounds. Therefore, the influence of TCDD, indolo[3,2-b]carbazole (ICZ, an NAhRA originating from cruciferous vegetables) and an NAhRA-containing extract of grapefruit juice (GJE) on BaP-DNA adduct formation in the human Caco-2 cell line was studied. Also, we investigated if different effects of TCDD, ICZ and GJE on adduct formation could be related to the modulation of transcription of biotransformation- and DNA-repair enzymes. Co-exposure to high AhR-activating concentrations of both TCDD and ICZ significantly reduced the amount of BaP-DNA adducts at 0.1 microM BaP, while at higher concentrations of BaP no influence was observed. In contrast, exposure to 0.1 microM BaP combined with GJE showed a significant increase in BaP-DNA adducts, and a significant decrease at 0.3 and 1 microM BaP. These differences could not be related to transcription of the phase I and II enzymes CYP1A1, CYP1B1, NQO1, GSTP1 and UGT1A6 or to transcription of the nucleotide excision repair enzymes ERCC1, XPA, XPC, XPF and XPG. We conclude that ICZ showed a similar effect on BaP-DNA adduct formation than TCDD, while GJE influenced the adduct formation in a different way. The difference in the influence on adduct formation may be due to effects at the level of enzyme activity, rather than gene expression.

Impact of multiple genetic polymorphisms on effects of a 4-week blueberry juice intervention on ex vivo induced lymphocytic DNA damage in human volunteers

Consumption of fruits and vegetables has been associated with a decrease in cancer incidence and cardiovascular disease, presumably caused by antioxidants. We designed a human intervention study to assess antioxidative and possible anti-genotoxic properties of fruit-borne antioxidants. We hypothesized that individuals bearing genetic polymorphisms for genes related to quercetin metabolism, benzo[a]pyrene metabolism, oxidative stress and DNA repair differ in their response to DNA protective effects of increased antioxidant intake. In the present study, 168 healthy volunteers consumed a blueberry/apple juice that provided 97 mg quercetin and 16 mg ascorbic acid a day. After a 4-week intervention period, plasma concentrations of quercetin and ascorbic acid and trolox equivalent antioxidant capacity (TEAC) were significantly increased. Further, we found 20% protection (P < 0.01) against ex vivo H(2)O(2)-provoked oxidative DNA damage, measured by comet assay. However, the level of ex vivo induced benzo[a]pyrene-diol-epoxide (BPDE)-DNA adducts was 28% increased upon intervention (P < 0.01). Statistical analysis of 34 biologically relevant genetic polymorphisms revealed that six significantly influenced the outcome of the intervention. Lymphocytes from individuals bearing variant genotype for Cyp1B1 5 seemed to benefit more than wild-types from DNA damage-protecting effects upon intervention. Variants for COMT tended to benefit less or even experienced detrimental effects from intervention. With respect to GSTT1, the effect is ambiguous; variants respond better in terms of intervention-related increase in TEAC, but wild-types benefit more from its protecting effects against oxidative DNA damage. We conclude that genotyping for relevant polymorphisms enables selecting subgroups among the general population that benefit more of DNA damage-modulating effects of micronutrients.

Dietary flavonoids induce MLL translocations in primary human CD34+ cells

Genetic abnormalities leading to infant leukemias already occur during fetal development and often involve rearrangements of the mixed-lineage leukemia (MLL) gene. These rearrangements resemble the aberrations observed in therapy-related leukemias following treatment with topoisomerase II (topoII)-inhibiting agents such as etoposide. Since flavonoids are potent topoII inhibitors, we examined the role of three widely consumed dietary flavonoids (quercetin, genistein and kaempferol) on the development of MLL rearrangements in primary human CD34(+) cells. Using the neutral Comet assay, we demonstrated a dose-dependent double-strand break (DSB) formation after exposure to flavonoids. An incorrect repair of these DSBs resulted in chromosomal translocations that co-localized with those identified in infant leukemias. Most of these translocations were formed by microhomology-mediated end joining. Moreover, in all but one translocation, SINE/Alu or LINE/L1 repetitive elements were present in at least one side of the breakpoint junction. Beside MLL translocations, fluorescence in situ hybridization analysis demonstrated monosomy or trisomy of MLL in 8-10% of the quercetin-exposed CD34(+) cells. Our study demonstrates that biologically relevant concentrations of flavonoids can induce MLL abnormalities in primary hematopoietic progenitor cells. This is particularly alarming knowing that the differences in metabolism and excretion rate between mother and fetus can lead to a higher flavonoid concentration on the fetal side. Therefore, it is important to raise public awareness and set guidelines for marketing flavonoid supplements to reduce the risk of infant leukemias.

Cigarette smoke-induced differential gene expression in blood cells from monozygotic twin pairs

Chemical carcinogenesis induced by lifestyle factors like cigarette smoking is a major research area in molecular epidemiology. Gene expression analysis of large numbers of genes simultaneously using microarrays holds the opportunity to study the effects of such an exposure at the genome level yielding more mechanism-based information. Therefore, the aim of our study was to investigate multiple gene expressions in blood, indicative for the effects caused by cigarette smoke. Smoking-discordant monozygotic twin pairs (n=9) were studied to diminish influences of genetic background. Using a dedicated microarray containing 600 toxicologically relevant genes, we investigated which genes are differentially expressed in smokers compared to non-smokers. We also looked for genes of which the expression changes correlated with DNA adducts, a biomarker of effective dose for exposure to cigarette smoke carcinogens. The mean DNA adduct level in smokers differed significantly from that in non-smokers (mean +/- standard error 1.96 +/- 0.24 versus 1.17 +/- 0.16 adducts per 10(8) nucleotides, respectively; P=0.04). The genes of which the expression differed most significantly between smokers and non-smokers are ATF4, MAPK14, SOD2, CYP1B1 and SERPINB2. CYP1B1 and SOD2 can directly be linked to cigarette smoke exposure, whereas the other genes are associated with stress or environmentally induced response. Main functions of the genes influenced by cigarette smoking comprise carcinogen metabolism, oxidative stress response and anti-apoptosis.

Genotoxicity and physicochemical characteristics of traffic-related ambient particulate matter

Exposure to ambient particulate matter (PM) has been linked to several adverse health effects. Since vehicular traffic is a PM source of growing importance, we sampled total suspended particulate (TSP), PM(10), and PM(2.5) at six urban locations with pronounced differences in traffic intensity. The mutagenicity, DNA-adduct formation, and induction of oxidative DNA damage by the samples were studied as genotoxicological parameters, in relation to polycyclic aromatic hydrocarbon (PAH) levels, elemental composition, and radical-generating capacity (RGC) as chemical characteristics. We found pronounced differences in the genotoxicity and chemical characteristics of PM from the various locations, although we could not establish a correlation between traffic intensity and any of these characteristics for any of the PM size fractions. Therefore, the differences between locations may be due to local sources of PM, other than traffic. The concentration of total (carcinogenic) PAHs correlated positively with RGC, direct and S9-mediated mutagenicity, as well as the induction of DNA adducts and oxidative DNA damage. The interaction between total PAHs and transition metals correlated positively with DNA-adduct formation, particularly from the PM(2.5) fraction. RGC was not associated with one specific PM size fraction, but mutagenicity and DNA reactivity after metabolic activation were relatively high in PM(10) and PM(2.5), when compared with TSP. We conclude that the toxicological characteristics of urban PM samples show pronounced differences, even when PM concentrations at the sample sites are comparable. This implies that emission reduction strategies that take chemical and toxicological characteristics of PM into account may be useful for reducing the health risks associated with PM exposure.

Applicability of the black slug Arion ater for monitoring exposure to polycyclic aromatic hydrocarbons and their subsequent bioactivation into DNA binding metabolites

The applicability of terrestrial black slugs Arion ater (Mollusca, Gastropoda) was studied for biomonitoring environmental exposure to polycyclic aromatic hydrocarbons (PAHs). In laboratory experiments, slugs were orally exposed to benzo[a]pyrene (BaP) for a short term (3 days) or a long term (119 days) period. Test animals were collected in the field, or were reared under laboratory conditions to ensure that they had no history of PAH-exposure. Benzo[a]pyrene hydroxylase (BPH) activity was measured in the digestive gland as a biomarker for BaP exposure. Bulky DNA adduct formation in kidney was measured as an effect biomarker for BaP bioactivation into DNA-binding metabolites. Although success of clutching was relatively low (5 out of 18 slugs produced egg packages), sufficient number of slugs were obtained to perform exposure experiments due to high hatching (89%) and survival rates (79%). After a short exposure to a relatively high BaP doses of 20 and 200 microg/g fresh feed, a dose-dependent and significant increase of BPH activity and bulky DNA adduct levels could be demonstrated in A. ater. Induction factors were low (two times control level), but optimization of the test conditions yielded a higher BPH induction factor of 4.8 times control level. BPH activity and bulky DNA adduct levels, however, did not increase after a long-term exposure to environmentally relevant BaP doses (upto 0.25 microg/g fresh feed). Based on this lack of response after realistic exposure it is concluded that A. ater is not sensitive to BaP exposure and, therefore, not suitable for monitoring environmental exposure to PAHs.

Myeloperoxidase (MPO) -463G->A reduces MPO activity and DNA adduct levels in bronchoalveolar lavages of smokers

The myeloperoxidase (MPO) -463G-->A genetic polymorphism is associated with a reduced risk for lung cancer, but the underlying mechanism is not yet elucidated. Therefore, the impact of this polymorphism on MPO activity and lipophilic DNA adducts was studied in respectively bronchoalveolar lavage (BAL) fluid and cells, from 106 smoking Caucasian lung patients. MPO activity was determined spectrophotometrically, aromatic DNA adducts by (32)P-postlabeling and MPO genotypes by RFLP analysis. Frequencies of MPO -463AA (13%), MPO -463AG (36%), and MPO -463GG (51%) were in line with earlier observations. MPO activity/neutrophil was lower in MPO -463AA (median 0.04 pU/cell) than in MPO -463AG (median 0.07 pU/cell) and MPO -463GG (median 0.14 pU/cell; P = 0.059) individuals. DNA adducts in BAL cells were measured in 11 MPO -463AA subjects and equal numbers of MPO -463AG and MPO -463GG subjects matched for smoking, age, gender, and clinical diagnosis. DNA adduct levels in MPO -463AA individuals (median 0.62 adducts/10(8) nucleotides) were lower than in MPO -463AG (median 1.51 adducts/10(8) nucleotides) and MPO -463GG (median 3.26 adducts/10(8) nucleotides; P = 0.003) subjects. Overall, no significant correlation was observed between amount of inhaled tar/day and DNA adduct levels. However, correlations improved considerably on grouping according to the MPO genotype; MPO -463AA subjects were the least responsive (R(2) = 0.73, slope = 0.4, P = 0.01) followed by MPO -463AG subjects (R(2) = 0.70, slope = 1.3, P = 0.01) and MPO -463GG patients (R(2) = 0.67, slope = 2.8, P = 0.02). These data demonstrate that MPO -463AA/AG genotypes are associated with (a) reduced MPO activity in BAL fluid and (b) reduced smoking-related DNA adduct levels in BAL cells in a gene-dose manner. These data provide a plausible biological explanation for the reduced risk for lung cancer as observed in MPO -463AA/AG compared with MPO -463GG subjects.

Myeloperoxidase (MPO) −463G→A Reduces MPO Activity and DNA Adduct Levels in Bronchoalveolar Lavages of Smokers

The myeloperoxidase (MPO) −463G→A genetic polymorphism is associated with a reduced risk for lung cancer, but the underlying mechanism is not yet elucidated. Therefore, the impact of this polymorphism on MPO activity and lipophilic DNA adducts was studied in respectively bronchoalveolar lavage (BAL) fluid and cells, from 106 smoking Caucasian lung patients. MPO activity was determined spectrophotometrically, aromatic DNA adducts by 32P-postlabeling and MPO genotypes by RFLP analysis. Frequencies of MPO −463AA (13%), MPO −463AG (36%), and MPO −463GG (51%) were in line with earlier observations. MPO activity/neutrophil was lower in MPO −463AA (median 0.04 pU/cell) than in MPO −463AG (median 0.07 pU/cell) and MPO −463GG (median 0.14 pU/cell; P = 0.059) individuals. DNA adducts in BAL cells were measured in 11 MPO −463AA subjects and equal numbers of MPO −463AG and MPO −463GG subjects matched for smoking, age, gender, and clinical diagnosis. DNA adduct levels in MPO −463AA individuals (median 0.62 adducts/108 nucleotides) were lower than in MPO −463AG (median 1.51 adducts/108 nucleotides) and MPO −463GG (median 3.26 adducts/108 nucleotides; P = 0.003) subjects. Overall, no significant correlation was observed between amount of inhaled tar/day and DNA adduct levels. However, correlations improved considerably on grouping according to the MPO genotype; MPO −463AA subjects were the least responsive (R2 = 0.73, slope = 0.4, P = 0.01) followed by MPO −463AG subjects (R2 = 0.70, slope = 1.3, P = 0.01) and MPO −463GG patients (R2 = 0.67, slope = 2.8, P = 0.02). These data demonstrate that MPO −463AA/AG genotypes are associated with (a) reduced MPO activity in BAL fluid and (b) reduced smoking-related DNA adduct levels in BAL cells in a gene-dose manner. These data provide a plausible biological explanation for the reduced risk for lung cancer as observed in MPO −463AA/AG compared with MPO −463GG subjects.

In vitro investigations into the interaction of -carotene with DNA: evidence for the role of carbon-centered free radicals

Supplementation by beta-carotene has unexpectedly appeared to increase lung cancer risk among smokers. In order to explain this it has been suggested that at high serum levels of beta-carotene, prooxidant characteristics of beta-carotene may become manifest, yielding reactive oxygen species (ROS) and inducing oxidative DNA damage. It has further been hypothesized that cigarette smoke carcinogens such as benzo[a]pyrene (B[a]P) and/or B[a]P metabolites, may directly react with beta-carotene. Furthermore, beta-carotene oxidation products may have a role in the bioactivation of B[a]P analogous to the peroxide shunt pathway of cytochrome P450 supported by cumene hydroperoxide. The aim of this study was to assess the effects of beta-carotene on the formation of B[a]P-DNA adducts and oxidative DNA damage in vitro in isolated DNA, applying as metabolizing systems rat liver and lung metabolizing fractions and lung metabolizing fractions from smoking and non-smoking humans. We established that beta-carotene in the presence of various metabolizing systems was unable to induce oxidative DNA damage (8-oxo-dG), although beta-carotene is capable of generating ROS spontaneously in the absence of metabolizing fractions. We also could not find an effect of beta-carotene on DNA adduct formation induced by B[a]P upon metabolic activation. We could, however, provide evidence of the occurrence of a carbon-centered beta-carotene radical which was found to be able to interact with B[a]P and to intercalate in DNA.

A molecular dosimetry approach to assess human exposure to environmental tobacco smoke in pubs

Although the involvement of environmental tobacco smoke (ETS) in human lung cancer is no longer a matter of dispute, the magnitude of its impact still is. This is mainly due to the inefficiency of methodology to assess exposure to ETS especially in public places. Setting a real life exposure condition (3 h stay in local pubs) and using a matched-control study design, we quantified smoke-related DNA adducts in induced sputum and peripheral blood lymphocytes (PBL) of healthy non-smokers (n = 15) before and after a single pub visit by means of the (32)P-post-labeling assay. For verification, we also measured a spectrum of polycyclic aromatic hydrocarbons (PAH) in the ambient air of the pubs by personal air monitors, and determined the plasma concentrations of nicotine and cotinine by gas chromatography/mass spectrometry. The ambient air concentrations of all PAH were several orders of magnitude higher than those already reported for other indoor environments. The plasma concentrations of both nicotine and cotinine increased significantly after the pub visit (P = 0.001 and P = 0.0007, respectively). Accordingly, the overall DNA adduct profile in induced sputum, but not in PBL, changed quantitatively and qualitatively after the pub visit. Of most significance was the formation of a distinct DNA adduct in induced sputum of three individuals consequent to ETS exposure. This adduct co-migrated with the standard (+/-)-anti-benzo[a]pyrene diol epoxide-DNA adduct, which is known to form at lung cancer mutational hotspots. We conclude that real life exposure to ETS can give rise to pro-mutagenic lesions in the lower airway, and this can be best investigated in a relevant surrogate matrix such as induced sputum.

Comparison between smoking-related DNA adduct analysis in induced sputum and peripheral blood lymphocytes

We investigated the applicability of induced sputum (IS), a non-invasive derivative from the lower respiratory tract, for smoking-related DNA adduct analysis and its comparability with peripheral blood lymphocytes (PBL). Lipophilic DNA adducts were quantified by the (32)P-post-labeling assay in IS and PBL of smokers (n = 9) with stable smoking status at three time points (one week intervals) and non-smokers (n = 9) at one time point. The success rate for sputum induction was 100% at all time points. There was no significant difference in total cell count, cell viability, squamous cell count and DNA yield between smokers and non-smokers. Within the smokers, there was no significant difference in IS cytology at the three time points: overall (mean of three measurements) total cell count, 9.0 +/- 2.4 x 10(6); cell viability, 77 +/- 4%; squamous cell count, 28 +/- 5%; non-squamous cell count, 72 +/- 4% (bronchoalveolar macrophages, 75 +/- 6%; neutrophils, 17 +/- 3%; bronchoepithelial cells, 7 +/- 2%; lymphocytes, 0.7 +/- 0.2%; metachromatic cells, 0.3 +/- 0.2%). IS DNA yield did not differ significantly at the three time points [overall (mean of three extractions) DNA yield, 66 +/- 20 microg]. A typical smoking-associated diagonal radioactive zone was observed in the adduct maps of IS and PBL of all and five smokers, respectively, and of none of the non-smokers. Lipophilic DNA adduct levels in both IS and PBL of smokers were higher than those of non-smokers (3.7 +/- 0. 9 versus 0.7 +/- 0.2/10(8) nt, P = 0.0005, and 2.1 +/- 0.3 versus 0. 6 +/- 0.1/10(8) nt, P = 0.0001, respectively). In smokers the level of adducts in IS was non-significantly higher than that in PBL (3.7 +/- 0.9 versus 2.1 +/- 0.3/10(8) nt, P = 0.1), whilst in non-smokers the difference was not appreciable (0.7 +/- 0.2 versus 0.6 +/- 0. 1/10(8) nt). Within the smokers there was no significant change in the level of adducts at the three time points either in IS or in PBL (coefficients of variation 34 and 29%, respectively). Adduct levels in IS at each time point were higher than those in PBL, leading to a significantly higher overall (mean of three quantifications) level of adducts in IS than PBL (3.3 +/- 0.2 versus 2.1 +/- 0.1/10(8) nt, P = 0.02). The overall levels of adducts in both IS and PBL were dose-dependently related to smoking indices. We conclude that IS is a preferable matrix as compared with PBL for molecular dosimetry of (current) exposure to inhalatory carcinogens as its analysis reveals both the existence and the magnitude of exposure more explicitly.

Applicability of induced sputum for molecular dosimetry of exposure to inhalatory carcinogens: 32P-postlabeling of lipophilic DNA adducts in smokers and nonsmokers

The lung is a major target organ for smoking-associated cancer. We examined the applicability of induced sputum for molecular dosimetry of exposure to tobacco smoke-related carcinogens. Sputum induction was performed by inhalation of 4.5% saline delivered from an ultrasonic nebulizer for a period of up to 21 min in a group of smoking (n = 20) and nonsmoking (n = 24) healthy individuals. Samples were analyzed for total and differential cell counts and cell viability. Subsequently, DNA contents of the samples were isolated, and measurement of lipophilic DNA adducts was done by the 32P-postlabeling assay using nuclease P1 (NP1) and butanol enrichment methods. All subjects tolerated the induction procedure without experiencing any troublesome symptoms, and 90% of smokers (18 of 20) and 88% of nonsmokers (21 of 24) succeeded in producing sufficient amounts of sputum. Total cell counts and percentages of viable cells in smokers were higher than those in nonsmokers (6.7+/-6.0 versus 4.7+/-6.0 x 10(6), P = 0.40 and 80+/-15 versus 63+/-17, P = 0.01, respectively). In cell differentials, smokers had lower percentages of bronchoalveolar macrophages and higher percentages of neutrophils (69+/-24 versus 92+/-5, P = 0.002 and 26+/-26 versus 4+/-4, P = 0.008, respectively). Using the NP1 digestion method, all smokers and only one nonsmoker showed a diagonal radioactive zone in their adduct maps; adduct levels in smokers were higher than those in nonsmokers (3.1+/-1.4 versus 0.6+/-0.8/10(8) nucleotides; P = 0.0007), and also, adduct levels were significantly related to smoking indices. Applying the butanol extraction method, however, only half of the smokers and three nonsmokers showed the diagonal radioactive zone in their adduct maps; adduct levels in smokers were higher than those in nonsmokers (4.6+/-3.7 versus 1.0+/-1.9/10(8) nucleotides; P = 0.02), and the levels of adducts were significantly related to the smoking indices. There was a correlation between the levels of adducts determined by the two enrichment methods (r = 0.7; P = 0.02). Paired comparison showed no differences between the levels of adducts measured by the two methods (P = 0.55). We conclude that induced sputum can serve for molecular dosimetry of inhalatory exposure to carcinogens and that the NP1 version of the 32P-postlabeling assay is a choice of preference for studying smoking-induced DNA adducts in the lower respiratory tract.

Induction of DNA adducts by several polychlorinated biphenyls

It is known that lower-chlorinated biphenyls are metabolically activated to electrophilic quinoid species capable of binding to DNA. Also, certain metabolites are capable of redox cycling, thereby increasing oxidative stress in biological systems. In the present study, we tested mono-, di-, tri-, tetra-, penta-, hexa-, and heptachlorinated biphenyls for their ability to bind with DNA and to induce oxidative DNA damage. We present additional evidence that several PCB congeners form DNA adducts after metabolic activation, which can be detected by the nuclease P1- or butanol-enrichment procedures of the (32)P-postlabeling technique. Butanol and nuclease P1 enrichments showed different adduct recoveries, depending on the level of chlorination of the biphenyls. Application of the nuclease P1 enrichment showed that the incubation of 2-chloro-; 3, 4-dichloro-; 2,4,4'-trichloro-; 3,4,5-trichloro-; and 2,2',5, 5'-tetrachlorobiphenyl with calf thymus DNA and liver microsomes from rats treated with phenobarbital, followed by oxidation with a peroxidase, produced five to eight different DNA adducts. For these lower-chlorinated biphenyls, butanol enrichment generally showed a lower recovery. For some higher substituted congeners (3,3',4,4', 5-pentachloro-, 2,2',3,4,4',5'-hexachloro-, 2,2',4,4',5, 5'-hexachloro-, and 2,2',3,4,4',5,5'-heptachlorobiphenyl), after butanol enrichment a single dominant spot was observed, which was absent in the nuclease P1 procedure. After incubation of calf thymus DNA with either higher- or lower-chlorinated PCB congeners, we were not able to detect significantly increased levels of oxidative DNA damage above background levels, measured as 8-oxo-7, 8-dihydro-2'deoxyguanosine. In view of the carcinogenicity of PCB mixtures in animals and the ability of PCB metabolites to bind covalently to DNA, rats were orally treated with a mixture of PCBs (Aroclor 1242). PCB-DNA adduct levels were analyzed in PCB target organs: liver, thymus, glandular stomach, spleen, testes, seminal vesicles and prostate DNA. In vivo PCB-DNA adducts could not be detected by either the butanol- or by the NP1-enrichment procedure in rat target tissue DNA. Also, no differences in oxidative DNA damage could be observed between PCB-treated rats and controls. These results indicate a lack of DNA reactivity of PCB mixtures in vivo.

Use of crayfish in biomonitoring studies of environmental pollution of the river Meuse

The river Meuse, located in western Europe, is contaminated by different pollutants, of both organic and inorganic nature. The predominant sources of Meuse contamination in The Netherlands are agricultural activities and pollution derived from urban areas. Crayfish, water, and sediment samples were collected at four different locations of the river Meuse, in order to cover a large part of the catchment area of this river in The Netherlands. Crayfish may be very useful in biomonitoring studies, since they can integrate body load by pollutants over time in an area-bound manner. In these crayfish, levels of aromatic DNA adducts, heavy metal residues, polychlorinated biphenyls (PCBs), and organochlorine pesticides were determined in hepatopancreatic tissue. Also analyzed were water and sediment samples derived from the same locations, for polycyclic aromatic hydrocarbons (PAHs), heavy metals, and organochlorine compounds. In sediments from the four different sampling sites, no clear differences were observed in PCB levels. Organochlorine pesticide concentrations were highest at location A, the most upstream sampling site, whereas a general decrease was observed following the river Meuse downstream. A similar pattern was observed for the metal compounds. For PAH sediment levels no consistent tendency could be observed. Highest values were detected at site B, followed by, respectively, locations A, D, and C. In water samples, a different pattern was observed. The highest metal concentration was observed at location D, whereas the total organochlorine level was higher at sites B and D, compared to the two other sampling sites. Differences in pollution levels in crayfish between sampling sites were evident. Site D, the most downstream-situated site examined, appeared to be the most polluted site with respect to PCBs, DDT, DDE, and Cu in crayfish. Moreover, DNA adduct levels, which may serve as a dosimeter for the internal dose of aromatic compounds such as PAHs and PCBs, were also significantly higher in hepatopancreatic tissue of crayfish captured at site D, compared to the three other sampling sites. Moreover, significant correlations were observed between DNA adduct levels and the lower chlorinated PCB congeners (PCB 28-PCB 101). By correlating the different pollutants in water and/or sediment with xenobiotic levels in crayfish, no consistency could be observed, indicating that monitoring aquatic species may provide specific information on the presence of surface water pollutants. These results indicate that crayfish can be used as biological indicators of exposure to both organic and inorganic pollution in aquatic systems.

Putative susceptibility markers of coronary artery disease: association between VDR genotype, smoking, and aromatic DNA adduct levels in human right atrial tissue

Cancer and cardiovascular diseases share risk factors such as smoking, and the onset of both diseases have been suggested to have a common mechanistic basis. The binding of carcinogens to DNA (carcinogen-DNA adducts), genetic polymorphisms in carcinogen-detoxifying enzymes glutathione S-transferases (GSTs), and genetic polymorphisms in the vitamin D receptor (VDR) are among the candidates for modifiers of cancer risk. We determined whether these biomarkers could be related to individual characteristics of patients suffering from cardiovascular diseases. For that purpose, DNA from the right atrial appendage of 41 patients who underwent open heart surgery was analyzed for smoking-related DNA adducts and polymorphisms in GSTM1, GSTT1, and VDR genes. Statistical analysis was used to identify any patient's characteristics associated with these molecular markers. Our results showed that heart tissue of cigarette smokers contained a variety of aromatic DNA adducts in significantly elevated levels compared to ex-smokers (P<0.01) or nonsmokers (P<0.001). A linear relationship was observed between DNA adduct levels and daily cigarette smoking (rs=0.73; P=0.0003). Since cardiac myocytes are terminally differentiated cells that have lost their ability to divide and seemingly have limited DNA repair capacities, their levels might accumulate with time and thereby affect heart cell function or viability. Substantial interindividual differences between DNA adduct levels were observed, and persons with severe coronary artery disease (CAD), as assessed by coronary angiography, had higher DNA adduct levels than persons with no or mild CAD (P=0.04). As polymorphisms in GST genes have been shown to modulate DNA adduct levels and risk for lung cancer in smokers, we explored for the first time whether the GST polymorphisms could also explain deviating heart DNA adduct levels and CAD risk. However, no relation could be found between these covariants. In contrast, a VDR genotype, which has been associated with decreased serum levels of the active hormonal form of vitamin D and increased risk for certain cancers, seemed to be related to severity of CAD (P=0.025). Our findings support the hypothesis that smoking-related DNA damage may be involved in the onset of cardiovascular diseases and suggest that VDR genotype may be a useful susceptibility marker of CAD.

Putative susceptibility markers of coronary artery disease: association between VDR genotype, smoking, and aromatic DNA adduct levels in human right atrial tissue

Cancer and cardiovascular diseases share risk factors such as smoking, and the onset of both diseases have been suggested to have a common mechanistic basis. The binding of carcinogens to DNA (carcinogen-DNA adducts), genetic polymorphisms in carcinogen-detoxifying enzymes glutathione S-transferases (GSTs), and genetic polymorphisms in the vitamin D receptor (VDR) are among the candidates for modifiers of cancer risk. We determined whether these biomarkers could be related to individual characteristics of patients suffering from cardiovascular diseases. For that purpose, DNA from the right atrial appendage of 41 patients who underwent open heart surgery was analyzed for smoking-related DNA adducts and polymorphisms in GSTM1, GSTT1, and VDR genes. Statistical analysis was used to identify any patient's characteristics associated with these molecular markers. Our results showed that heart tissue of cigarette smokers contained a variety of aromatic DNA adducts in significantly elevated levels compared to ex-smokers (P<0.01) or nonsmokers (P<0.001). A linear relationship was observed between DNA adduct levels and daily cigarette smoking (rs=0.73; P=0.0003). Since cardiac myocytes are terminally differentiated cells that have lost their ability to divide and seemingly have limited DNA repair capacities, their levels might accumulate with time and thereby affect heart cell function or viability. Substantial interindividual differences between DNA adduct levels were observed, and persons with severe coronary artery disease (CAD), as assessed by coronary angiography, had higher DNA adduct levels than persons with no or mild CAD (P=0.04). As polymorphisms in GST genes have been shown to modulate DNA adduct levels and risk for lung cancer in smokers, we explored for the first time whether the GST polymorphisms could also explain deviating heart DNA adduct levels and CAD risk. However, no relation could be found between these covariants. In contrast, a VDR genotype, which has been associated with decreased serum levels of the active hormonal form of vitamin D and increased risk for certain cancers, seemed to be related to severity of CAD (P=0.025). Our findings support the hypothesis that smoking-related DNA damage may be involved in the onset of cardiovascular diseases and suggest that VDR genotype may be a useful susceptibility marker of CAD.

The use of 4-aminobiphenyl hemoglobin adducts and aromatic DNA adducts in lymphocytes of smokers as biomarkers of exposure

Two biomarkers of exposure to cigarette smoke, 4-aminobiphenyl-hemoglobin (Hb) adducts and aromatic DNA adducts in lymphocytes, were determined from a population of 55 smokers and 4 nonsmokers. The levels of these adducts were related to daily cigarette consumption and also to (calculated) tar and nicotine intake. The Hb adduct levels seemed to correspond best to the number of cigarettes (cig) smoked, but at a cigarette consumption of >30 cig/day, a saturation effect was observed. Lymphocytic DNA adducts also correlated well with cigarette and tar consumption; for this type of adduct, a saturation level was reached at a dose of approximately 15-20 cig/day. From a subpopulation, a second sample was obtained after 2 months, and the adduct levels were compared with their initial adduct levels. Strong correlations were found between the first and second DNA adduct measurements (r = 0.84). In another subpopulation, resampling was performed after 6 months. No correlation between DNA adduct levels in the first and last samples was found, but 4-aminobiphenyl Hb adduct levels were strongly correlated (r = 0.78), the absolute quantities measured being comparable (paired t test: t = -1.27, P = 0.22, n = 15). We found no influence of GSTM1 and NAT2 polymorphisms on Hb adduct formation and of GSTM1 polymorphism on aromatic DNA adduct formation. A significantly lower aromatic DNA adduct level was observed for intermediate acetylators when compared to slow acetylators.

Differences in aromatic-DNA adduct levels between alveolar macrophages and subpopulations of white blood cells from smokers

The 32P-post-labelling assay for DNA adduct quantification gives the opportunity to examine endogenous exposure to DNA reactive compounds. Most human biomonitoring studies applied white blood cells (WBC) or cells obtained by broncho-alveolar lavages (BAL) as source of DNA, but still it is not clear what cell type represents the most reliable indicator for exposure to cigarette smoke-associated genotoxins. At first, we examined DNA adduct levels by means of nuclease P1 (NP1) enriched 32P-post-labelling in separated WBC subpopulations after in vitro incubations for 18 h with 10 microM benzo[a]pyrene (B[a]P). DNA adduct levels were highest in monocytes (10.7 +/- 2.9 adducts/10(8) nucleotides, n = 8), followed by lymphocytes (5.9 +/- 1.7, n = 8), and granulocytes (0.5 +/- 0.2, n = 8). Secondly, aromatic-DNA adduct levels were determined in BAL cells and WBC-subsets from (non-)smoking volunteers. In smoking individuals, adduct levels were in the ranking order: BAL cells (3.7 +/- 1.0, n = 5) > monocytes (2.0 +/- 0.5, n = 8) > or = lymphocytes (1.6 +/- 0.4, n = 8) > granulocytes (0.8 +/- 0.2, n = 8) by NP1-enrichment and monocytes (9.0 +/- 3.2, n = 5) > or = lymphocytes (8.0 +/- 2.1, n = 6) > granulocytes (2.1 +/- 0.3, n = 7) by butanol-enriched 32P-post-labelling. Aromatic-DNA adduct levels were significantly higher in WBC-subsets of smokers as compared with non-smokers, except for DNA adducts in granulocytes using butanol enrichment. Thirdly, dose-response relationships were investigated in mononuclear white blood cells (MNC, i.e. monocytes plus lymphocytes) and BAL-cells of a larger group of smoking individuals (n = 78). Adduct levels in MNC were related to daily exposure to cigarette-tar (r = 0.31, P < 0.01). Adduct levels in BAL cells seemed to be correlated with pack-years, but after correction for age this relationship was lost. Butanol extraction resulted in 5-6-fold higher DNA adduct levels in MNC, whereas butanol extraction of BAL-DNA of the same individuals yielded only 2-fold higher adduct levels. The two enrichment procedures of 32P-post-labelling were correlated in BAL cells (r = 0.86, P < 0.001, n = 12). We conclude that particularly MNC are good surrogates for the detection of smoking-related DNA adducts.

Influences of DNA isolation and RNA contamination on carcinogen-DNA adduct analysis by 32P-postlabeling

32P-Postlabeling is a widely applied assay for the analysis of carcinogen-DNA adducts. Optimization of most steps in this assay has been given attention, but influences of DNA isolation and DNA purity on adduct quantitation have not been investigated systematically. In this study, DNA was isolated from human lymphocytes exposed to benzo[a]pyrene (B[a]P, 10 microM) for 18 hr and from liver of rats i.p.-treated with B[a]P (10 mg/kg body weight) using two different DNA isolation methods: a phenol-extraction and a salting-out procedure. Subsequently, DNA was analysed by nuclease P1 (NP1) or butanol-enriched 32P-postlabeling. Influences of RNA contamination were studied by labeling RNA isolated from in vitro exposed lymphocytes. In the in vitro experiment, DNA adduct levels were significantly higher using the salting-out procedure (63.2 +/- 13.7 adducts per 10(8) nucleotides, n = 9) as compared with the phenol-extraction (14.3 +/- 0.8). RNA was approximately 4 times less efficiently labeled as compared to DNA. Nonetheless, RNA contamination of DNA samples may result in an overestimation of DNA adduct levels when butanol enrichment is used, because RNA adduct levels seemed to be substantially higher than DNA adduct levels in the same cells. DNA adduct analysis by nuclease P1 enrichment is probably less affected, since RNA adducts appeared to be NP1 sensitive. In vivo, three different adducts were found by NP1 enriched 32P-postlabeling in the liver of B[a]P-exposed rats. Again, DNA adduct levels were significantly higher using salting out as compared to phenol extraction for the adduct which comigrated with the BPDE-DNA adduct standard (adduct 1) and an unknown adduct (adduct 2). However, the results were the opposite for another B[a]P-derived DNA adduct (adduct 3). Our results suggest that differences in DNA isolation procedures as well as RNA contamination influence quantitative DNA adduct analysis by 32P-postlabeling.

32P-postlabelling of aromatic DNA adducts in white blood cells and alveolar macrophages of smokers: saturation at high exposures

DNA adducts may serve as a molecular dosimeter of exposure to cigarette smoke-associated carcinogens such as polycyclic aromatic hydrocarbons (PAH). Target tissues for cigarette smoke-induced carcinogenesis are rarely accessible; therefore, peripheral blood cells or cells obtained by bronchoalveolar lavage (BAL) may be used as surrogate sources of exposed DNA. However, the relationship between cigarette smoke exposure and aromatic-DNA adducts in white blood cells and BAL cells is still unclear. In this study, we examined DNA adduct formation in lymphocytes and BAL cells in several populations of smoking individuals by means of 32P-postlabelling. Significant correlations between the amount of cigarettes smoked per day and the level of aromatic-DNA adducts were found in lymphocytes. In BAL cells, DNA adduct levels were associated with age (p = 0.05) and gender (p = 0.10) after adjustment for smoking behaviour. Adduct formation levelled off at higher exposure levels, suggesting less efficient adduct formation; decreases in the formation of adducts per unit of exposure were found in lymphocytes (r(s) = -0.80, p < 0.001) and BAL cells (r(s) = -0.72, p < 0.001). To assess intra-individual variation in adduct levels at constant smoking behaviour, sampling was repeated after a period of 2 and 6 months. In lymphocytes, repeated measurements with an interval of 2 months were highly correlated (r = 0.84, p = 0.009, n = 8), whereas repeated measurements with an interval of 6 months showed no correlation (r = 0.30, p = 0.27, n = 16). Repeated measurements in BAL cells showed a significant correlation after 6 months (r = 0.68, p = 0.03, n = 10). Furthermore, in a group of occupationally exposed aluminium workers, adduct levels in total white blood cells were correlated with the average concentrations of PAH in the ambient air of workers who smoked cigarettes, whereas in non-smokers, no such relationship was found. We conclude that cigarette smoking may directly or indirectly influence DNA adduct levels and saturation of DNA adduct formation may occur, leading to non-linear dose-response relationships.

Possible relevance of pigeons as an indicator species for monitoring air pollution

Wild city pigeons were caught at four different locations in the Netherlands to represent areas of high (Amsterdam-high), moderate (Amsterdam-medium), and low (Maastricht and Assen) traffic density. It is assumed that local ambient air pollution decreases as a function of traffic density. In these pigeons levels of polycyclic aromatic hydrocarbon (PAH)-DNA adducts, oxidative DNA damage, and heavy metal residues were determined in kidney, lung, liver, and blood (no adduct analysis in blood). The contribution of leaded gasoline to total body lead content was estimated by measuring concentrations of Pb and its isotopes in blood. We also analyzed samples of ambient air particulate matter for PAH and heavy metal concentrations at the four different locations. Interregional differences in heavy metals in ambient air particulate matter were reflected relatively well by pigeon body loads. The higher lead and cadmium concentrations in blood, kidney, liver, and lung were found in the Amsterdam high traffic density area, followed by Amsterdam medium, Assen, and Maastricht. A high Pb concentration in blood coincided with relatively low 206Pb/207Pb values, indicating a high contribution of leaded gasoline to total blood Pb concentrations in pigeons from the Amsterdam high traffic density area. Significantly enhanced blood zinc values were found in pigeons from both locations in Amsterdam compared to pigeons from the other two areas. However, no differences in Zn tissue levels between the four different groups were found. Oxidative DNA damage, determined as the ratio of 7-Hydro-8-oxo-2'-deoxyguanosine/ deoxyguanosine, in pigeon liver was highest in Amsterdam-high, followed by Assen (low traffic density). Pb content, but not the Cd content, was positively associated with oxidative DNA damage in liver tissue. In lung tissue, a negative correlation was found between oxidative DNA damage and Zn content. These results indicate that the carcinogenic potential of Pb might be ascribed to oxygen radical formation, whereas Zn plays a protective role against oxidative DNA damage. Places with high and medium traffic density could be clearly discriminated on the basis of PAH levels in the ambient air. The PAH content in particulate air samples was not, however, reflected in total PAH-related DNA adduct levels because no differences could be observed in tissue adduct levels in pigeons from the four different locations. Our results indicate that wild city pigeons can be used as biological indicators of exposure to heavy metal pollution in outdoor air.

B[a]P-DNA adduct formation and induction of human epithelial lung cell transformation

In this study we tested the suitability of the human epithelial lung cell line BEAS-2B for in vitro studies of lung carcinogenesis. The human bronchial epithelial lung cell line BEAS-2B, immortalized with an SV-40/Ad-12 hybrid virus construct, was treated for 24 hours with five different concentrations of the lung carcinogen benzo(a)pyrene (B[a]P) to assess the relationship between DNA adduct levels, cell cycle distribution, micronuclei formation (MN), colony forming efficiency (CFE), and anchorage independent growth (AIG). There appeared to be a strong linear correlation between B[a]P concentration and DNA adduct formation, but no difference in cell cycle distribution was observed after incubation with various concentrations of B[a]P. In the incubation range of 4 to 100 nM B[a]P, the number of DNA adducts was linearly correlated with colony formation in AIG and with the number of cells within individual colonies but not the number of colonies in the CFE test. At higher B[a]P concentrations, the clonal expansion of cells in the CFE and the number of colonies in the AIG declined. Also, the number of micronuclei increased with the formation of DNA adducts. It is concluded that after 24 hours of incubation with 100 nM B[a]P, the formation of BPDE-DNA adducts in the human epithelial lung cells BEAS-2B results in maximal induction of cell transformation. Because of this correlation between DNA adduct formation and lung epithelial cell transformation, the BEAS-2B cells seem suitable for in vitro studies on lung carcinogens.

Leadership development plan. A CQI approach to management performance appraisals

In 1993 managers at St. Mary's Hospital Medical Center established the attributes necessary to be a successful leader in St. Mary's continuous quality improvement culture. These leadership attributes formed the basis of a new performance appraisal system for managers. The medical center adopted its new performance appraisal system at the beginning of fiscal year 1994-1995. The objective of the plan is to develop St. Mary's managers' leadership skills. St. Mary's Leadership Development Plan is an ongoing cycle, with three phases. First, managers and administrative representatives jointly agree on objectives to discuss throughout the fiscal year. The objectives reflect the hospital planning and financial goals and objectives, department goals and objectives, and leadership growth opportunities. Each manager is then responsible for gathering feedback from subordinates on how well he or she is meeting the set objectives. Finally, each manager and administrative representative highlight accomplishments achieved during the fiscal year. St. Mary's decided to discontinue pay-for-performance salary increases beginning with the 1994-1995 fiscal year, coinciding with the initiation of the Leadership Development Plan. Manager's compensation is now a flat percentage increase granted to all managers.

DNA dosimetry in biological indicator species living on PAH-contaminated soils and sediments

A large variety of environmental carcinogens are metabolically activated to electrophilic metabolites that can bind to nucleic acids, forming covalent adducts. In organisms possessing active metabolic systems for a particular carcinogen, DNA adducts generally have longer biological half-lives than the substrate carcinogens. Thus, measurement of specific DNA adduct concentrations in terrestrial and water organisms may provide a relevant biological indicator of prior exposure to environmental carcinogens. Analysis of carcinogen load in indicator species with specific behavioral patterns may indicate human exposure risk to environmental carcinogens. Recently, sensitive assays have been developed to measure carcinogen-DNA adducts in organisms exposed to complex mixtures such as polycyclic aromatic hydrocarbons (PAH). At first instance, the nuclease P1 version of the 32P-postlabeling assay was used to examine the liver of eel (Anguilla anguilla) for the presence of aromatic DNA adducts. The fish were collected from six freshwater sites in the Amsterdam area with different levels of PAH contamination in their sediments. Chromatograms derived from DNA of fish from polluted sites revealed a broad diagonal zone indicating the presence of DNA adducts containing aromatic or bulky hydrophobic moieties not present in DNA of fish from an unpolluted reference site. Significant correlations were found between the aromatic DNA adducts levels and the levels of PAH in sediments (P < 0.001). To examine the validity of DNA adduct dosimetry in terrestrial organisms earthworms (Lumbricus terrestris) were kept on industrially contaminated PAH soils for several weeks. Several aromatic DNA adducts could be detected in DNA from the exposed earthworms; adduct levels were significantly increased with increasing exposure time.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation of aromatic DNA adducts in white blood cells in relation to urinary excretion of 1-hydroxypyrene during consumption of grilled meat

With the aim of studying the effect of oral exposure to polycyclic aromatic hydrocarbons (PAH) on human DNA-adduct formation in mononuclear cells and excretion of 1-hydroxypyrene in urine, we examined the effect of consumption of charcoal-broiled hamburgers. Hamburgers were grilled and samples were homogenized, saponified, extracted with hexane and analysed for PAH content by HPLC. The mean levels of benzo[a]pyrene and pyrene in the grilled hamburgers were 8.6 and 26.5 micrograms/kg respectively. Twenty one healthy non-smoking individuals consumed two hamburgers (170 g) per day for 5 days. 32P-Postlabelling analysis was performed on DNA samples of mononuclear cells of the subjects. The excretion of 1-hydroxypyrene in urine was studied as a marker of endogenous exposure to PAH. In the DNA samples of eight of the 21 subjects, on day 3 of the consumption period a predominant adduct spot could be detected with similar chromatographic properties to a benzo[a]pyrenediolepoxide--deoxyguanosine standard, the levels varying between 3 and 103 adducts/10(10) nucleotides. Analysis of the urine samples revealed maximal 1-hydroxypyrene excretion on day 3 in all nine subjects who collected urine daily during the consumption week, with an average level of 5.2 nmol/24 h. In a subsequent study in which six volunteers consumed charcoal-broiled hamburgers with lower levels of benzo[a]pyrene and pyrene, no aromatic DNA adducts in mononuclear cells or increased 1-hydroxypyrene levels in urine were detected. In conclusion, oral intake of PAH may dose-dependent induce elevated levels of aromatic DNA adducts in mononuclear cells and of 1-hydroxypyrene in urine, indicating substantial bioactivation of PAH, in particular via this route.

Measurement by 32P-postlabeling of (+/-)anti-benzo[a]pyrene-diolepoxide-N2-deoxyguanosine adduct persistence in unstimulated human peripheral blood lymphocytes

In order to study the relative importance of endogenous and environmental factors for the individual relation between DNA damage and DNA excision repair, a method was developed for measuring quantitatively the persistence of N2-deoxyguanosine adducts formed in non-stimulated isolated human peripheral blood lymphocytes after in vitro incubation with 0.2 microM (+/-)anti-BPDE, applying 32P-postlabeling. Total binding of radiolabeled (+/-)anti-BPDE to DNA and its removal has been studied previously in human peripheral blood lymphocytes, but the method presented here enables the direct investigation of repair of the main (+/-)anti-BPDE-DNA adduct, which is implicated in benzo[a]pyrene-induced mutagenesis. Using this method, it was found that in lymphocytes, obtained from 5 individuals, most (+/-)anti-BPDE-N2-dG adducts are removed within the first 24 h after treatment, while interindividual differences appear to exist in both adduct formation and rate and extent of removal.

Disposition of single oral doses of butylated hydroxytoluene in man and rat

The kinetics and metabolism of butylated hydroxytoluene (BHT) in man and rats have been compared. Single oral doses of 200, 63 or 20 mg BHT/kg body weight were administered to rats and a single oral dose of 0.5 mg/kg body weight was ingested by human volunteers (non-smoking males). In rats, kinetic parameters (area under the plasma concentration-time curve, plasma BHT peak levels) showed a dose-dependent increase. Plasma BHT levels after oral administration were about four times higher than those that have been reported for another synthetic food antioxidant, butylated hydroxyanisole (BHA; Verhagen et al., Fd Chem. Toxic. 27, 151-158). This may be a reflection of a smaller volume of distribution for BHT, since there were no differences in plasma elimination half-life or plasma clearance between BHT and BHA. In man, the mean plasma concentration-time profile after oral BHT intake was well below the BHT profiles observed for rats and closely followed plasma BHA kinetics in man. In rats, the simultaneous administration of BHT (200 mg/kg body weight) and BHA (200 mg/kg) significantly decreased the absorption of BHT from the gastro-intestinal tract in the first few hours after treatment; the plasma kinetics of BHA were not influenced by the simultaneous administration of BHT. In human female volunteers no alterations in plasma BHT or BHA profiles were seen after the simultaneous ingestion of BHT (0.25 mg/kg body weight) and BHA (0.25 mg/kg). Rats excrete about 10% of an oral dose of 200 mg BHT/kg as unchanged BHT in the faeces, whereas in man no BHT could be detected in the faeces. Urinary excretion of (un)conjugated 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) accounts for only a small percentage of the administered dose in both rats and humans. It is concluded that the plasma BHT concentrations reached after the administration of a single medium to high dose of BHT to rats or a single low dose to man are very different.

Effect of subacute oral intake of the food antioxidant butylated hydroxyanisole on clinical parameters and phase-I and -II biotransformation capacity in man

A study is presented in which eight healthy male non-smoking volunteers ingested a daily amount of 0.5 mg/kg butylated hydroxyanisole (BHA) for 10 consecutive days. Blood samples were taken on days -6 and 0 before and on days 4 and 7 after the first BHA administration for the assessment of standard clinical plasma parameters (L-aspartate aminotransferase, L-alanine-aminotransferase, L-gamma-glutamyltranspeptidase, creatine phosphokinase, lactate dehydrogenase, total protein, albumin, urea, creatinine, Na+, and Cl-). Antipyrine (500 mg p.o.) and paracetamol (500 mg p.o) were administered before and during BHA administration as test substances to measure phase-I and phase-II biotransformation capacity. Saliva samples and urine were subsequently collected for the assessment of kinetic parameters (e.g. saliva elimination half-life, saliva clearance, apparent volume of distribution) and urinary excretion of metabolites. Kinetic plasma parameters of BHA itself were determined in plasma samples obtained via a catheter in an arm vein after oral BHA intake on days 0 and 7. Levels of antipyrine, paracetamol, BHA and metabolites in plasma, saliva or urine were quantified by standard or newly developed reversed-phase high-performance liquid chromatography methods. Urinary excretion of Na+, K+, and Cl-, as well as osmolality of urine were measured on three days before and six days during BHA administration. Generally, no significant differences were detected in the parameters measured, indicating that oral administration of BHA to men for 10 days remains without effects on clinical biochemical parameters and phase-I and phase-II biotransformation capacity. In contrast, urinary excretion of metabolites of BHA was significantly increased on days 3 and 7 vs. the first day of BHA administration.(ABSTRACT TRUNCATED AT 250 WORDS)