Search PubMed⌕ Search

Biomedical subjects

M Castegnaro

Publications and source records attributed to M Castegnaro.

At least 37 records · Page 2Linked to original sources
PubMed1997

Evaluation of the genotoxic activity of metronidazole and dimetridazole in human lymphocytes by the comet assay.

The genotoxicity of metronidazole (MZ) and dimetridazole (DZ) has been evaluated in human lymphocytes using the comet assay. The test has been performed using 3 doses (58.4, 175.2 and 292.1 microM for MZ; and 70.9, 212.6 and 354.3 microM for DZ) under 3 experimental protocols: aerobiosis, anaerobiosis (90% N2, 10% CO2) and with the presence of the microsomal fraction S9 mix. The effects of 4 antioxidants (8-hydroxyquinoline (8HQ), vitamin C (VitC), catalase (CAT) and superoxide dismutase (SOD), have been investigated on DNA damage generated by fixed concentrations of MZ (292.1 microM) and DZ (354.4 microM). In aerobic conditions, MZ and DZ produced significant dose-response relationships. The dose-related effects of both drugs decreased or were abolished in anaerobic conditions or in presence of S9 mix. 8HQ, VitC, CAT and SOD induced dose-related protective responses against DNA damage due to MZ and DZ. These findings suggest that MZ and DZ induce DNA damage in human lymphocytes through the futile cycle. The one-electron reduction of the drugs leads to the production of nitro radical anions. In the presence of oxygen, these radicals are reoxidized and generate oxygen-activated species.

Animals↗
PubMed1997

Absence of a synergistic effect between fumonisin B1 and N-nitrosomethylbenzylamine in the induction of oesophageal papillomas in the rat.

Fumonisins and N-nitrosamines (NNO) are suggested risk factors in the development of human oesophageal cancer; exposure to both occurs in high risk populations in Africa and People's Republic of China. The hypothesis that the two would interact in oesophageal carcinogenesis was therefore tested by treating male rats with the known oesophageal carcinogen N-methylbenzylnitrosamine (NMBA), and fumonisin B1 (FB1). The treatment groups were: Group 1, NMBA (2.5 mg/kg) intraperitoneally twice per week from week 2 to 4 inclusive; Group 2, as for group 1 but in addition FB1 (5 mg/kg) daily from weeks 1 to 5 inclusive by gavage; Group 3, FB1 (5 mg/kg) alone daily from weeks 1 to 5 inclusive by gavage, and Group 4, vehicle treatment from week 1 to 5 inclusive. Two of 12 animals in group 1 developed oesophageal papillomas and a further two had oesophageal dysplasia. Data were similar in group 2, animals receiving both NMBA and FB1, with one of 12 animals having papillomas and three of 12 with dysplasia. Sphingolipid biosynthesis was affected in the kidney and slightly in the liver after fumonisin treatment but not in the oesophagus or lung as determined by sphinganine:sphingosine ratios in urine and tissues. These data show that there is no synergistic interaction between NMBA and FB1 in the rat oesophagus when the two compounds are administered together. It is nevertheless important to examine other experimental models and treatment protocols which may be more relevant to the human situation and also to pursue epidemiological investigations of the role of fumonisins in oesophageal cancer.

Animals↗
PubMed1997

Chemical degradation of wastes of antineoplastic agents: cyclophosphamide, ifosfamide and melphalan.

Handling genotoxic compounds commonly used in cancer chemotherapy generates contaminated wastes that require decontamination before disposal. Chemical methods are an alternative and/or a complement to incineration for the treatment of wastes and spills. As part of a program initiated by the International Agency for Research on Cancer (IARC), three chemical methods readily available in the hospital environment, viz sodium hypochlorite (NaOCl, 5.25%), hydrogen peroxide (H2O2, < or = 30%) and Fenton reagent (FeCl2, 2H2O; 0.3 g in 10 ml H2O2, 30%), were tested for the degradation of three alkylating agents (cyclophosphamide, CP; ifosfamide, IF, and melphalan). Pharmaceutical preparations corresponding to the most highly concentrated administration solutions in either NaCl (0.9%) or dextrose (5%) were inactivated by oxidation volume/volume with each of the methods for at least 1 h. The efficiency of degradation was monitored by high-pressure liquid chromatography. The mutagenicity of the degradation residues was tested by means of the Ames test using tester strains of Salmonella typhimurium TA 97a, TA 98, TA 100 and TA 102 with and without an exogenous metabolic activation system. Complete disappearance of CP was observed after 1 h with all degradation methods. However, direct mutagens were generated by the Fenton oxidation technique in the presence of dextrose (5%). IF was completely degraded by the Fenton reagent and NaOCl methods. No mutagenic residues were detected after 1 h of treatment with the Fenton technique, and after 3 h with the NaOCl method. Direct-acting mutagens remained after the H2O2 treatment in the presence of dextrose (5%). Complete degradation of melphalan was achieved in 1 h by each of the three methods, and no mutagenic residues were produced by any of the treatments. The use of NaOCl (5.25%) proved the most efficient system for degradation of the three alkylating agents.

Animals↗
PubMed1997

Chemical degradation of wastes of antineoplastic agents. 2: Six anthracyclines: idarubicin, doxorubicin, epirubicin, pirarubicin, aclarubicin, and daunorubicin.

OBJECT: Handling of genotoxic compounds commonly used in cancer chemotherapy generates contaminated wastes that require decontamination before disposal. Chemical methods are an alternative and/or a complement to incineration for the treatment of wastes and spills. METHODS: As part of a program initiated by the International Agency for Research on Cancer (IARC), 3 chemical methods readily available in the hospital environment--sodium hypochlorite (NaOCl, 5.25%), hydrogen peroxide (H2O2, < or = 30%) and Fenton reagent (FeCl2, 2H2O; 0.3 g in 10 ml H2O2, 30%)--are being tested for the degradation of a total of 32 antineoplastic agents. The efficiency of degradation was monitored by high-pressure liquid chromatography. The mutagenicity of the degradation residues were tested by the Ames test using tester strains Salmonella typhimurium TA 97a, TA 98, TA 100, and TA 102 with and without an exogenous metabolic activation system. RESULTS: The first results obtained for the degradation of cyclophosphamide, ifosfamide, and melphalan have been published in this journal. The present manuscript reports the results of the investigation of a series of six anthracyclines (aclarubicin, daunorubicin, doxorubicin, epirubicin, idarubicin, and pirarubicin) commonly used in chemotherapy treatment. Pharmaceutical preparations corresponding to the most concentrated administration solutions in either NaCl (0.9%) or dextrose (5%) were inactivated by oxidation volume/volume with each of the methods for at least 1 h. Complete degradation into nonmutagenic residues of all the tested compounds was observed after 1 h for the NaOCl (5.25%) treatment as previously reported for the first study. CONCLUSION: Sodium hypochlorite (5.25%) is an efficient reagent for the chemical degradation of the nine drugs tested thus far.

Animals↗
PubMed1996

In vitro studies of the genotoxic effects of bitumen and coal-tar fume condensates: comparison of data obtained by mutagenicity testing and DNA adduct analysis by 32P-postlabelling.

Bitumens contain traces of polycyclic aromatic compounds (PACs), a part of which will end up in the fumes emitted during hot handling of bitumen-containing products, e.g. during roadpaving. Although exposure of workers to these fumes is low, it might lead to health problems. Studies on bitumen fume condensates (BFCs) showed weak to moderate mutagenic activities, but studies on DNA adduct formation have not been reported. Therefore, a study was initiated in which fumes were generated from two road grade bitumens, in such a way that they were representative of the fumes produced in the field. The combined vapour/particulates were tested in vitro for their ability to produce DNA adducts and in modified Ames mutation assays, using a number of different strains. An attempt was made to relate the results to chemical data, such as the content of a number of individual polycyclic aromatic hydrocarbons (PAHs) and with a measure for the total PAC content. As a reference material fume condensate from coal-tar (coal-tar pitch volatiles; CTPV) were subjected to the same tests. All fume condensates tested were mutagenic to all strains and induced the formation of DNA adducts. The patterns of DNA adducts, obtained by 32P-postlabelling, arising from the BFCs were qualitatively different from the patterns of adducts obtained from the CTPVs, implying qualitative differences in the nature of the compounds responsible for the formation of these adducts. This is corroborated by the observation that for BFCs quantitative adduct levels are higher than would be expected based on the PAH content. These data thus indicate that the PAHs analysed are not the sole components responsible for adduct formation from BFCs, but that an important contribution comes from other (hetero- and/or substituted-) PACs.

Animals↗
PubMed1996

Development of a new method for the analysis of sphinganine and sphingosine in urine and tissues.

The fumonisins are inhibitors of de novo sphingolipid biosynthesis in vitro and in vivo and thus possibly interfere with the regulation of cell growth, differentiation, and neoplastic transformation. In addition, the ratio of free sphinganine (Sa) to free sphingosine (So) has been proposed as a marker of exposure for animals or humans consuming feed or food contaminated by these toxins. A method to analyze these sphingolipid bases has been proposed [Merrill et al., 1988: Anal Biochem 171:373-381; Riley et al., 1994a: JAOAC 77:533-540] but involves numerous steps and consequently is not ideally suited to the analysis of large numbers of samples, as is often required in epidemiological studies. A new method was therefore developed for the analysis of the Sa/So ratio in tissues as well as human and rat urine. Briefly, the method involves isolation of exfoliated cells from as little as 0.5 ml of rat urine or 2 ml of human urine followed by a rapid and efficient extraction of sphingolipid bases in ethyl acetate, an optimized derivatization step with o-phthaldialdehyde and a high-pressure liquid chromatography separation on a 250 mm x 4.6 mm. 5 microns Kromasil C18 column, with a 4-step phosphate buffer/methanol gradient. Fluorescence was monitored at 340 nm excitation, 455 nm emission, and retention times for So, Sa, and C-20 Sa were about 11, 14, and 22 min, respectively. The method was adapted to tissue analysis by partially digesting approximately 30 mg tissue with trypsin to permit isolation of a cell pellet before extraction of the sphingolipids as described above. The method was applied to the analysis of So and Sa in urines and tissues of fumonisin B1 (FB1) treated and untreated male BDIV rats. The Sa/So ratio in urine of untreated rats varied from 0.1 to 0.7, and for treated rats (between 1-5 mg FB1/kg body weight daily by gavage), the ratio was between 1.2-10. In kidney, the ratio was 0.1 in control rats and varied from 4 to 10.3 in treated rats. In human urine, measurements could easily be made in 2 ml of urine in females, but in males much larger volumes were required due to the low levels of sphingolipid bases.

Adolescent↗
PubMed1996

Optimization of the Salmonella/mammalian microsome assay for urine mutagenesis by experimental designs.

Assessing urine mutagenicity with the Salmonella mutagenicity test is often limited by the volumes of the samples. Optimization of the assay was performed with factorial and Doehlert designs. Two fractional factorial designs 2(3-1) (3 factors, 4 experiments) were used to estimate the main effects of the percent S9 in the mix, the time of liquid incubation, the inoculum size and the growth conditions. A Doehlert design (3 factors, 13 experiments) was used to study the main effects and the interactions of the NADP, G6P and S9 in the mix. The positive markers were benzo[a]pyrene (BaP, 0.3 microgram/plate) and a pool of smokers' urine (SU, 1.25 ml equivalent/plate). The response was limited to the induction factor (IF, number of induced revertants/number of spontaneous revertants) with Salmonella typhimurium TA98. The optimal conditions for BaP were: a 60 min period of liquid incubation and a volume of 0.1 ml (approx. 10(8) cells/plate) of an overnight culture grown in 50 ml of Nutrient Broth No. 2 from a 250 ml flask. The S9 mix (0.1 ml, final volume) included 1.5% of S9, 1.0 mM NADP and 4.4 mM G6P. The maximal IF was 15.79. The optimal conditions for SU were: a 60 min period of liquid incubation and a volume of 0.1 ml (approx. 10(8) cells/plate) of an overnight culture grown in 7 ml of Nutrient Broth No. 2 from a 20 x 180 mm tube. The S9 mix (0.1 ml, final volume) included: 4% S9, 4.2 mM NADP and 5.2 mM G6P. The maximal IF was 10.95. These optimal conditions did not modify the spontaneous frequencies of the tester strains: TA97a, TA98, TA100 and TA102. The dose-response curves of mutagenic urine samples were found to be non-linear. This micromethod required 8-fold less urine sample and 12.5-fold less liver homogenate as compared to the standard plate incorporation assay and was from 6.2- to 11.8-fold more sensitive to evaluate urine mutagenicity. The sensitivity of this technique was found to be limited to individuals smoking more than approx. 5 cigarettes/day by the standard extraction-concentration procedure.

Dose-Response Relationship, Drug↗
PubMed1996

Molecular and epidemiological approaches to the etiology of urinary tract tumors in an area with Balkan endemic nephropathy.

Recently, we completed a second biostatistical study of urinary tract tumors (UTT) in areas with Balkan endemic nephropathy (BEN) in the Vratza district, Bulgaria, during the period 1975 to 1991. We confirmed the positive correlation between the incidence of urinary tract tumors (UTT) and BEN demonstrated in our first population-based case control 1977 study. A UTT incidence of 98.9 per 100,000 men and 74.7 per 100,000 women was found in villages most affected by BEN when compared with 11.0 and 6.7 for men and women, respectively, in nonendemic villages. The relative risk (RR) of UTT in BEN villages showed tumors of kidney pelvis and ureters-29 in men and 35 in women and urinary bladder tumors-4 in men and 11 in women. The percentage of food and blood samples containing nephrotoxic and carcinogenic mycotoxin Ochratoxin A (OTA) correlated with the origin of the samples. The most contaminated samples were found in BEN villages and households, and the urinary excretion of OTA was higher in the group of BEN/UTT patients. The UTT DNA's were studied by the 32P-postlabeling method for the presence of OTA-DNA adducts. Some OTA-DNA adducts characteristic for endemic UTT and absent in control nonendemic UTT and nontumorous tissues were described for the first time.

Animals↗
PubMed1995

Formation of ochratoxin A metabolites and DNA-adducts in monkey kidney cells.

Monkey kidney cells (named Vero cells) were incubated with increasing doses of ochratoxin A (10-100 microM). The inhibiting concentration 50% (IC50) on protein synthesis was about 14 microM in the presence of 5% fetal calf serum and 37 microM in the presence of 10% fetal calf serum. Some metabolites of ochratoxin A, including the chlorinated dihydroisocoumarin moiety of OTA (OT alpha), 4-[S]-hydroxy-OTA and 4-[R]-hydroxy-OTA were detected by HPLC in the mixture of cell homogenate after a 24 h incubation with 10 and 25 microM of OTA. Using the 32P-postlabelling method, several DNA-adducts, similar to those formed in mouse kidney after OTA treatment, were detected in monkey kidney cells. Thus, Vero cells are suitable for genotoxic and cytotoxic studies in relation to the metabolism of nephrotoxic xenobiotics such as OTA.

Animals↗
PubMed1995

IARC activities in mycotoxin research.

The creation of the International Agency for Research on Cancer (IARC) in May 1965 occurred only two years after publication of the chemical structure of the aflatoxins, and the investigation of a possible link between exposure to these compounds and liver cancer incidence was initiated by IARC as early as 1968. Thus, mycotoxins were one of the first topics of research at IARC and the Agency's special interest in cancer in developing countries has contributed to a sustained effort in this research field. The work performed comprises a number of aspects including laboratory research into mechanisms of action and methods for destruction of mycotoxins, epidemiological studies, and through evaluation of the carcinogenic potency of these toxins in the "IARC Monographs on the Evaluation of the Carcinogenic Risks to Humans." A particular feature has been the integration into epidemiological studies of biomarkers of mycotoxin exposure (e.g., to aflatoxin, ochratoxin A) developed in the IARC laboratories. The above research areas are described briefly below and future activities are discussed in relation to present knowledge and the possibilities of achieving primary prevention of cancer. Another field of activity in which IARC has been strongly involved is that of quality assurance with the organisation of the mycotoxin check sample programme [Friesen, 1989: J Toxicol-Toxin Reviews 8:363-373]. This activity will, however, not be discussed in this article in view of space limitations.

Aflatoxins↗
PubMed1995

Metabolic polymorphism affecting DNA binding and excretion of carcinogens in humans.

A case-control study on lung cancer patients demonstrated the pronounced effect of tobacco smoke on pulmonary carcinogen metabolism and suggested the existence of a metabolic phenotype at higher risk for tobacco-associated lung cancer. Lung cancer patients who were recent smokers showed in their lungs (i) significantly induced CYP1A1-related enzyme activity vs smoking non-lung cancer patients; (ii) increased benzo(a)pyrene (BP) tetrol formation from BP 7,8-diol by lung microsomes; and (iii) high levels of cytochrome P4501a1 by immunohistochemical staining. Levels of bulky aromatic DNA adducts (by 32P-postlabelling) and of BP-diol-epoxide (BPDE) adducts (by HPC/fluorometry) were quantified in lung parenchyma. Aryl hydrocarbon hydroxylase activity and the level of BPDE-DNA adducts (r = 0.91; p < 0.001) and to a lesser degree bulky DNA adducts were correlated. Thus pulmonary CYP1A1 expression (inducibility) controls in part polycyclic aromatic hydrocarbon-DNA adduct formation in tobacco smokers and, therefore, appears to be associated with lung cancer risk. High risk subjects for lung cancer among smokers may be identifiable through genotyping for polymorphic drug metabolizing enzymes in combination with molecular dosimetry of carcinogen-DNA adducts and mutation analysis in target (surrogate) cells. Such studies in a Finnish cohort of lung cancer patients and controls are in progress. Interim results of the effect of metabolic polymorphism on the level of PAH-DNA adducts and on the excretion of mutagens in urine are summarized.

Biotransformation↗
PubMed1994

Potassium permanganate can be used for degrading hazardous compounds.

Solutions of potassium permanganate in 3 M sulfuric acid, 1 M sodium hydroxide solution, and water can be used to degrade hazardous compounds. Excess oxidant can be removed by using sodium metabisulfite. Manganese, a carcinogen and mutagen, can be removed from the final reaction mixtures by making these mixtures strongly basic. Aqueous dilution causes the soluble potassium sulfate to dissolve while still allowing the insoluble manganese compounds to be removed by filtration and so reduces the weight of precipitate. In all cases the amount of manganese left in the filtrates was less than 2 ppm and the reaction mixtures were nonmutagenic. When ethanol was used as a test compound, degradation was much more rapid when the solvent was 3 M sulfuric acid or 1 M sodium hydroxide solution than when the solvent was water. However, the variation of the rate of reaction with pH depends on the nature of the substrate. Thus the effectiveness of the various methods may vary for other substrates. Potassium permanganate in sulfuric acid was used to degrade four polycyclic heterocyclic hydrocarbons. Destruction was greater than 99.9% and the final reaction mixtures contained no more than 0.5 ppm manganese and were not mutagenic. By modifying the work-up procedures to remove manganese from the final reaction mixture, procedures previously developed for degrading hazardous compounds can still be employed.

Chemical Phenomena↗
PubMed1993

Ochratoxin A-related DNA adducts in urinary tract tumours of Bulgarian subjects.

Ochratoxin A (OTA), a natural contaminant of mouldy food and feed, is suspected of being one of the etiological agents responsible for Balkan endemic nephropathy (BEN) and the associated urinary tract tumours. We have previously shown that ochratoxin A is genotoxic as expressed by DNA single-strand breaks. DNA-OTA adducts have been detected in various mouse organs after ochratoxin A treatment. Tumorous tissues from three kidneys and five bladders of Bulgarian patients undergoing surgery for cancer and from three non-malignant kidneys collected from French subjects were analysed for DNA adducts. Several adducts with the same RF values as those obtained from mouse kidney after treatment with OTA (one major and some minor adducts) were detected, mainly in kidney but also in bladder tissues from Bulgaria. No adducts were detected in French kidney tissues. These results provide new evidence of the possible role of OTA in the development of tumours of the urinary tract in Bulgaria.

Animals↗
PubMed1993

Analysis of DNA adducts in smokers' lung and urothelium by 32P-postlabelling: metabolic phenotype dependence and comparisons with other exposure markers.

Carcinogen-DNA adduct levels in lung parenchyma (surgical specimens) and urothelial (exfoliated) cells of smokers, ex-smokers and non-smokers were investigated. DNA adducts were analysed by 32P-postlabelling and levels were compared with tissue-specific activity of cytochrome P450-related enzymes, or whenever possible, with metabolic phenotypes and other macromolecular adducts. Lung cancer patients who were recent smokers had significantly induced benzo[a]pyrene (BaP)-3-hydroxylase (AHH) and ethoxycoumarin O-deethylase activities in lung parenchyma compared with smoking non-cancer patients. Pulmonary AHH activity showed a good correlation with the intensity of immunohistochemical staining for P4501A(1). In lung cancer patients from Italy and Finland who were recent smokers, lung AHH activity was positively correlated (r approximately 0.65; p < 0.001) with bulky DNA adduct levels. In some lung DNA samples from smokers, the level of BaP-diol-epoxide adducts determined by HPLC with fluorescence detection showed significant positive correlation with lung AHH activity and bulky DNA adduct levels. Molecular dosimetry studies provided evidence that aromatic amines such as 4-aminobiphenyl (ABP) in tobacco smoke are primarily responsible for bladder cancer in smokers. The N-(deoxyguanosin-8-yl)-4-ABP adduct was the major smoking-related adduct in DNA of bladder biopsies from bladder cancer patients and in the DNA of exfoliated urothelial cells of smoking volunteers. The adduct levels of ABP with haemoglobin and with deoxyguanosine in urothelial DNA (determined by 32P-postlabelling) were linearly and significantly correlated, and both were related to recent cigarette smoking. Metabolic phenotype (fast/slow N-acetylator and N-oxidizer) significantly affected the levels of ABP-haemoglobin adducts.

Aryl Hydrocarbon Hydroxylases↗
PubMed1993

Results of an interlaboratory trial of 32P-postlabelling.

An interlaboratory 32P-postlabelling trial involving 15 independent investigators was conducted. Each participant was provided with four DNA samples: 1, control DNA; 2, benzo[a]pyrene-modified DNA from mouse skin; 3, DNA from the lung of a tobacco smoker; 4, 2-acetylaminofluorene-modified DNA from mouse liver. The participants analysed the DNA samples by 32P-postlabelling using the standard procedure and using two procedures, nuclease P1 digestion and butanol extraction, to enhance the sensitivity of the assay. The qualitative and quantitative reproducibility of the results obtained by the different investigators are presented. A workshop discussion on postlabelling procedures is summarized.

2-Acetylaminofluorene↗
PubMed1993

Some safety procedures for handling 32P during postlabelling assays.

32P is a high-energy (1.7 MeV) beta-emitter. Its handling is therefore subject to regulation and very strict control. During the postlabelling procedure, numerous steps involve exposure to 32P. The main risk from exposure is through irradiation, but direct accidental contamination can occur. The various manipulation steps (ATP synthesis, labelling, chromatography, quantification) have been analysed for their contribution to potential radiation exposure. Several measures have been taken in the IARC laboratories to minimize exposure of all personnel involved, including those who handle radioactive wastes, since most of the initial radioactivity is eventually discarded. The various steps to be taken for minimizing exposure, such as the training of personnel using fluorescent compounds instead of radioactivity, the use of protective screens and of equipment specially adapted for this work, are reviewed.

Equipment and Supplies↗
PubMed1992

An improved fluorometric assay for dosimetry of benzo(a)pyrene diol-epoxide-DNA adducts in smokers' lung: comparisons with total bulky adducts and aryl hydrocarbon hydroxylase activity.

An improved high-performance liquid chromatography/fluorometric assay has been established to quantitate the benzo(a)pyrene (BP) tetrols released after acid hydrolysis of lung DNA from lung cancer patients, so that the formation of benzo(a)pyrene diol-epoxide-DNA adducts can be measured. The r-7,c-10,t-8,t-9-tetrahydroxy-7,8,9,10-tetrahydro-BP isolated by high-performance liquid chromatography was determined by chromatography in two different solvent systems and fluorescence spectroscopy. This assay has a detection limit of 2 pg of r-7,c-10,t-8,t-9-tetrahydroxy- 7,8,9,10-tetrahydro-BP, requires 100-500 micrograms of DNA, and can measure 1 adduct/10(8) unmodified nucleotides. As this assay does not use immunoaffinity chromatography or solvent extraction, it allows a > 90% recovery of benzo(a)pyrene diol-epoxide-DNA adducts. This procedure has been tested on 13 DNA samples prepared from nontumorous lung parenchyma taken from lung cancer patients at surgery and revealed the presence of DNA adducts of the anti-benzo(a)pyrene diol-epoxide in 9 of 11 samples from smokers and in 2 of 2 ex-smokers. In only two samples from smokers the formation of adducts derived from syn-benzo(a)pyrene diol-epoxide was detected. A 15-fold variation in DNA adduct level was found in 11 of 13 DNA samples, with a range of 0.6-9.9 adducts of benzo(a)pyrene diol-epoxide/10(8) nucleotides. In samples containing both anti- and syn-benzo(a)pyrene diolepoxide-DNA adducts, the anti/syn adduct ratio is 2:1. A highly significant correlation was found between pulmonary microsomal aryl hydrocarbon hydroxylase activity and the level of benzo(a)pyrene diolepoxide-DNA adduct (r = 0.91; P < 0.001; n = 13). A crude linear correlation between the amounts of these adducts and those of bulky DNA adducts determined by 32P-postlabeling assay was observed in the same samples (r = 0.78; P < 0.02; n = 13). Thus this highly sensitive and specific procedure is suitable for measuring benzo(a)pyrene diolepoxide-DNA adducts in human tissues from environmentally exposed subjects and could be adapted to measure polycyclic aromatic hydrocarbons other than BP.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗