Measles, polio and tetanus toxoid antibody levels in Gambian children aged 3 to 4 years following routine vaccination

A nation-wide cross-sectional survey of 816 children 3-4 years old was carried out in The Gambia between September 1990 and July 1991 to assess the seroprevalence of antibodies against 3 diseases included in the expanded programme on immunization: measles, poliomyelitis and tetanus. Among 689 children whose records were available, 94.5% were fully immunized. Measles vaccine was administered to 97% of the children and 91% of these had detectable antibodies at the time of the survey. Antibodies against type 1 and type 3 polioviruses, after up to 6 doses of oral polio vaccine, were present in 88.1% and 89.3% of the children respectively. Ninety-seven percent of the children who had received 4 doses of diphtheria-pertussis-tetanus vaccine (DPT) and 91% of those who received 3 doses had detectable tetanus toxoid antibodies at the age of 3-4 years. This study shows that serological responses to EPI vaccines given in infancy persist at very satisfactory levels throughout early childhood.

Matrix design for matrix-assisted laser desorption ionization: Sensitive determination of PAH-DNA adducts

Two matrices, 4-phenyl-α-eyanocinnamic acid (PCC) and 4-benzyloxy-α-eyanocinnamic acid (BCC), were identified for the determination of polycyclic aromatic hydrocarbon (PAH) adducts of DNA bases by matrix-assisted laser desorption ionization. These matrices were designed based on the concept that the matrix and the analyte should have structural similarities. PCC is a good matrix for the desorption of not only PAH-modified DNA bases, but also PAHs themselves and their metabolites. Detections can be made at the femtomolar level.

[Automatic implantable defibrillators; subdiaphragmatic insertion]

Although the material and techniques of implantation of the electrodes of implantable defibrillators have been improved, the abdominal implantation of the generator remains widely used as described by Mirowski in 1980. Despite a progressive reduction in their size, the generators remain bulky and a source of local complications. The risks and discomfort of implantation in the abdominal wall led the authors to try subdiaphragmatic implantation in 22 patients. There was no morbidity with perfect healing in all 22 cases. The mean follow-up period was 11 months. The patients felt very comfortable, a significant advance with respect to abdominal implantations.

Formation of DNA adducts in rat lung following chronic inhalation of diesel emissions, carbon black and titanium dioxide particles

Exposure of rats to diesel emissions results in the development of lung tumors. The objective of this study was to determine whether the polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs or other polycyclic organic matter adsorbed to diesel particles induces the formation of DNA adducts in the lung when compared to particles with little or no adsorbed organic matter. Rats were exposed to diesel emissions containing particles with over 30% solvent-extractable adsorbed organic matter and to particles with < 0.1% adsorbed organic matter (carbon black particles and TiO2). Wistar rats were exposed to diesel emissions (7.5 mg/m3) for 2 months, 6 months and 2 years and for 2 years to carbon black (11.3 mg/m3) and TiO2 particles (10.4 mg/m3) to compare tumorigenic response and DNA adduct formation in the lung. Two versions of the 32P-postlabeling assay for the detection of DNA adducts were used to tentatively identify nitrated-amine or arylamine adducts formed relative to other nitro PAH based on the demonstrated sensitivity of these adducts to nuclease P1 treatment. Total adduct levels were determined for peripheral lung tissue DNA as detected in a diagonal radioactive zone. One major adduct which migrated outside this region (adduct 1) and a nuclease P1-sensitive adduct (adduct 2) were quantitated separately. Adduct 1 increased significantly over time in the filtered air exposed animals but decreased markedly at the 2 year time points regardless of particle type, presumably as a result of adduct dilution through de novo cell synthesis or cell proliferation invoked in response to particle loading and/or effect on the endogenous synthesis or degradation of DNA reactive moieties. The nuclease sensitive adduct (adduct 2), possibly resulting from exposure to nitro-PAHs, was detected in diesel-exposed rats but was not detected in the rats exposed to TiO2 and carbon black. No significant elevation in PAH-derived adducts, relative to the filtered air controls, was observed in the rodents exposed to diesel emission. Our data suggest that long-term contact with these particles may result in a cell proliferative response, enhanced degradation of I-compounds not related to cell proliferation, and/or synthesis of I-compounds, irrespective of the differences in organic content associated with the three particle types. This response may be an important factor in explaining the reported similarity in tumorigenic response in rodents exposed to diesel emissions, carbon black and TiO2 particles.

Separation of 32P-postlabeled DNA adducts of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons by HPLC

The 32P-postlabeling assay, thin-layer chromatography, and reverse-phase high-pressure liquid chromatography (HPLC) were used to separate DNA adducts formed from 10 polycyclic aromatic hydrocarbons (PAHs) and 6 nitrated polycyclic aromatic hydrocarbons (NO2-PAHs). The PAHs included benzo[j]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, benzo[a]pyrene, chrysene, 6-methylchrysene, 5-methylchrysene, and benz[a]anthracene. The NO2-PAHs included 1-nitropyrene, 2-nitrofluoranthene, 3-nitrofluoranthene, 1,6-dinitropyrene, 1,3-dinitropyrene, and 1,8-dinitropyrene. Separation of seven of the major PAH-DNA adducts was achieved by an initial PAH HPLC gradient system. The major NO2-PAH-DNA adducts were not all separated from each other using the initial PAH HPLC gradient but were clearly separated from the PAH-DNA adducts. A second NO2-PAH HPLC gradient system was developed to separate NO2-PAH-DNA adducts following one-dimensional TLC and HPLC analysis. HPLC profiles of NO2-PAH-DNA adducts were compared using both adduct enhancement versions of the 32P-postlabeling assay to evaluate the use of this technique on HPLC to screen for the presence of NO2-PAH-DNA adducts. To demonstrate the application of these separation methods to a complex mixture of DNA adducts, the chromatographic mobilities of the 32P-postlabeled DNA adduct standards (PAHs and NO2-PAHs) were compared with those produced by a complex mixture of polycyclic organic matter (POM) extracted from diesel emission particles. The diesel-derived adducts did not elute with the identical retention time of any of the PAH or NO2-PAH standards used in this study. HPLC analyses of the NO2-PAH-derived adducts (butanol extracted) revealed the presence of multiple DNA adducts.(ABSTRACT TRUNCATED AT 250 WORDS)

[Implantation of automatic defibrillators by means of video-thoracoscopy. Authors' experience]

The implantable cardioverter-defibrillator represents an effective option for some potentially lethal ventricular arrhythmias. Nowadays defibrillation electrodes are often endoluminal only. In some patients, however, the presence of high defibrillation thresholds mandates the implantation of a subcutaneous patch. If the subcutaneous patch does not allow a sufficient decrease in defibrillation threshold, then two epicardial patches are generally implanted by different surgical approaches. Nevertheless surgical trauma could be a serious hazard in unstable patients. In 6 patients in whom endoluminal electrodes did not allow a safe defibrillation threshold, an extrapericardial patch has been implanted by means of a video-thoracoscopic approach: a left subcostal incision is performed and the subdiaphragmatic extraperitoneal space is reached; a patch electrode is then introduced into the left pleural cavity by blunt dissection of the diaphragm. This patch is positioned under thoracoscopic control in contact to the left pericardial surface and fixed by single stitches sutures. The impulse generator is finally implanted into the subdiaphragmatic pocket. In all the patients the patch electrode configuration sufficiently decreased defibrillation thresholds. In one of the patients a stellectomy was thoracoscopically performed to treat the long QT syndrome which was the cause of the ventricular fibrillation episodes. Defibrillation thresholds were confirmed after 8 day and 2 months postoperatively. In conclusion, the thoracoscopic implantation of an extrapericardial patch has allowed a significant reduction of defibrillation thresholds, without recurring to a major surgical procedure.

Induction of the CYP4A subfamily by perfluorodecanoic acid: the rat and the guinea pig as susceptible and non-susceptible species

Male Wistar rats and male Duncan Hartley guinea pigs were treated with one i.p. dose of perfluorodecanoic acid (PFDA) resulting in pronounced hepatomegaly in the rat but not the guinea pig. PFDA treatment also resulted in a 4-fold induction of lauric acid 12-hydroxylase activity in the rat but not the guinea pig, indicating induction of the CYP4A subfamily of isoenzymes. Consistent with this latter conclusion, Western blot analysis of rat liver microsomes using an antibody to CYP4A1 and Northern blot analysis of RNA extracts using a CYP4A1 cDNA probe, revealed PFDA-dependent induction of the CYP4A subfamily in the rat but not the guinea pig. Taken collectively, our data has demonstrated that PFDA, like other peroxisome proliferators, is also a CYP4A inducer and conforms to the well-documented species specificity in induction for this class of compound.

Induction of cytochrome P4504A by the peroxisome proliferator perfluoro-n-octanoic acid

The influence of a single dose of the peroxisome proliferator, perfluoro-n-octanoic acid (PFOA) on hepatic and renal mixed-function oxidase activities has been examined in rats. Peroxisome proliferation was confirmed by increases in peroxisomal palmitoyl-CoA oxidation and carnitine acetyl transferase activity, particularly in liver. The liver was also more susceptible than the kidney to PFOA-dependent induction of the 12-hydroxylation of lauric acid, suggesting induction of the CYP4A sub-family. This was further confirmed by Western blot analyses, wherein an anti-CYP4A1 antibody revealed a substantial PFOA-dependent induction of CYP4A1 in a pattern similar to that observed for the classical peroxisome proliferator, clofibrate. In addition, using a cDNA probe to CYP4A1 in Northern blot analysis, PFOA treatment resulted in a marked increase in the steady state level of CYP4A1 mRNA, again more extensively in liver than in kidney. Taken collectively, our data provide compelling evidence that PFOA, like other peroxisome proliferators, is also an inducer of the CYP4A subfamily.

Phase II trial for intraperitoneal cisplatin plus intravenous sodium thiosulphate in advanced ovarian carcinoma patients with minimal residual disease after cisplatin-based chemotherapy--a phase II study of the EORTC Gynaecological Cancer Cooperative Group

On the basis of its efficacy against ovarian carcinoma and its safe peritoneal administration, cisplatin administered by the intraperitoneal route was studied in a phase II multicentric trial. 34 patients with good performance status and residual disease less than 1 cm were treated with a 90 mg/m2 dose (60 mg/m2 at first cycle), administered in the abdominal cavity every 3 weeks for at least four cycles. In case of haematological or renal toxicity, intravenous sodium thiosulphate was perfused simultaneously with intraperitoneal cisplatin with protective intent. 25 patients were evaluable for response: 3 patients had pathological complete response and 1 patient had a microscopic disease (16% response rate in evaluable patients). Systemic toxicity was mild, and sodium thiosulphate clearly protected against leucopenia (6 patients) and renal toxicity (8 patients). Local side-effects were evaluable in 34 patients with 2 cases of infectious peritonitis, 1 of wound infection and 2 of haemorrhage. Of the 147 evaluable chemotherapy cycles, nine resulted in partial and one in total inflow obstruction, for which 4 patients needed surgical procedures for catheter-related complications, and 1 patient died of acute abdominal complications after such a procedure. We conclude that 90 mg/m2 intraperitoneal cisplatin has activity in pretreated patients with minimal residual disease, and that thiosulphate protects against haematological and renal toxicities. Only a randomised study can demonstrate a true benefit, which will have to be balanced with the toxicity of intraperitoneal drug administration.

Comparison of DNA adduct levels in human placenta from polychlorinated biphenyl exposed women and smokers in which CYP 1A1 levels are similarly elevated

Previous studies demonstrated that cigarette smoking is associated with high elevations in levels of both cytochrome P450 1A1 (CYP1A1) and DNA adducts in human placenta. To date, the identity of the smoking related DNA adducts is not known. The DNA adducts identified in placenta of smokers could result from chemicals present in cigarette smoke, substances formed by CYP 1A1 metabolic activation of endogenous compounds, noncigarette related exposures or a combination of these processes. Exposure to contaminated rice oil containing large doses of polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) also resulted in massive elevation of CYP 1A1 in human placenta but formation of DNA adducts directly from this exposure has not previously been reported. The purpose for comparing the two populations was to test the hypothesis that if CYP 1A1 induction results in the metabolic activation of endogenous compounds, then DNA adducts should also be present in PCB/PCDF exposed tissues exhibiting high CYP 1A1 activity and some of the adducts detected in the placental DNA from smokers may be identified as those derived from the metabolic activation of endogenous compounds. To test this hypothesis, we measured DNA adducts using 32P-postlabeling to analyze placental DNA from women exposed to PCB/PCDF and from cigarette smokers where levels of CYP 1A1 were similarly elevated. There was no evidence of DNA adducts among specimens obtained from PCB/PCDF exposed individuals. These data suggest that CYP 1A1 induction alone (in the absence of cigarette smoking) does not induce the formation of DNA adducts detectable by this approach, and that smoking related adducts are not a consequence of CYP 1A1 induction mediated activation of endogenous compounds or xenobiotics other than cigarette smoke.

Regulation of glycogen synthase activity in isolated rat adipocytes by levamisole

The effect of levamisole on glycogen synthase activity in isolated adipocytes was studied. The addition of levamisole to these cells resulted in an acute concentration-dependent increase in glycogen synthase activity. In contrast, epinephrine, dibutyryl cyclic AMP (DcAMP) and cysteamine decreased glycogen synthase activity. The stimulatory effect of levamisole on the activity of the enzyme was not affected by the presence of epinephrine but was diminished when either DcAMP or cysteamine was present. The results of this study suggest that levamisole increases adipocyte glycogen synthase activity by a mechanism that can be reversed by the elevation of cAMP.

Enoximone and acute left ventricular failure during weaning from mechanical ventilation after cardiac surgery

OBJECTIVE

To evaluate enoximone, a phosphodiesterase III inhibitor, in the treatment of left ventricular failure during the weaning of patients from mechanical ventilation after heart surgery.

DESIGN

Open label, prospective, weaning trial.

SETTING

Cardiothoracic surgical intensive care unit (ICU) in a university hospital.

PATIENTS

Nine patients were studied after one or more unsuccessful attempts at weaning from mechanical ventilation due to left ventricular dysfunction.

INTERVENTION

For each patient, two respiratory weaning attempts were studied: the first one as a control and the second one with enoximone infused at a rate of 30 micrograms/kg/min for 30 mins, then at a rate of 10 micrograms/kg/min.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic measurements were performed at the following interval times: baseline during mechanical ventilation; during spontaneous ventilation with a T-piece for a minimum of 10 mins; during mechanical ventilation after the enoximone infusion for 30 mins; during spontaneous ventilation for a minimum of 10 mins with an enoximone infusion running. During spontaneous ventilation, enoximone increased cardiac index by 34% but mean artery, right atrial, and pulmonary artery occlusion pressures did not change. Despite an increase in venous admixture due to augmented cardiac index and inhibition of hypoxic vasoconstriction, no oxygen debt occurred because oxygen delivery increased. Seven of nine patients were weaned successfully from mechanical ventilation.

CONCLUSION

Because of its positive inotropic and vasodilatory properties, enoximone is helpful for respiratory weaning of patients with left ventricular failure after cardiac surgery.

14-Day continuous infusion of mitoxantrone in hormone-refractory metastatic adenocarcinoma of the prostate

A dose-finding investigation was conducted with mitoxantrone administered as 14-day continuous infusions to patients with hormone-refractory metastatic adenocarcinoma of the prostate. Fifteen men participated in four dosage groups: mitoxantrone 1.0, 1.25, 1.4, and 1.5 mg/m2/day; a treatment cycle was defined as a dose of mitoxantrone given over 2 weeks, followed by 2 weeks of monitoring prior to the next course. The patients received 1 to 10 courses, with the majority receiving 1 to 3. The maximum tolerated dose was 1.25 mg/m2/day for 14 days of continuous infusion. Two patients discontinued treatment because of gastrointestinal effects. Most adverse clinical experiences were mild or moderate in intensity. A decrease in prostate-specific antigen (PSA) response was seen after one course in 6 of 14 patients who had PSA measurements. Stable disease was achieved in 40% of the evaluable patients, and some quality of life parameters improved. Further clinical trials with mitoxantrone are indicated in patients with prostatic cancer, especially in those who have had less previous treatment.

Adducts of 6-methylbenzo[a]pyrene and 6-fluorobenzo[a]pyrene formed by electrochemical oxidation in the presence of deoxyribonucleosides

Studies of the DNA adducts of benzo[a]pyrene and selected derivatives are part of the strategy to elucidate mechanisms of tumor initiation by aromatic hydrocarbons. Reference adducts formed by reaction of deoxyribonucleosides with electrophilic intermediates of 6-fluorobenzo[a]pyrene (6-FBP) and 6-methylbenzo[a]pyrene (6-CH3BP) are investigated here because they are essential for identifying the structures of adducts formed in biological systems. Electrochemical oxidation of 6-FBP in the presence of deoxyribonucleosides led to adducts from the 6-FBP radical cation. With dG, a mixture of 6-FBP bound at C-1 or C-3 to the N-7 of Gua was formed in 10% yield, whereas 6-FBP plus dC gave a mixture of 3-(6-FBP-1-yl)Cyt and 3-(6-FBP-3-yl)Cyt (15%). No adducts of 6-FBP were formed with dA or dT. Electrochemical oxidation of 6-CH3BP in the presence of dG produced 8-(BP-6-CH2-yl)dG (5%) and a mixture of 7-(6-CH3BP-1-yl)Gua and 7-(6-CH3BP-3-yl)Gua (23%). The only adduct formed with dA was 3-(BP-6-CH2-yl)Ade (9%). 6-CH3BP did not afford any adducts with dC or dT. The noncarcinogenic 6-ClBP and 6-BrBP did not produce adducts with dG, dA, dC, or dT. These results are consistent with the chemical properties of the 6-FBP and 6-CH3BP radical cations: that is, 6-FBP reacts at C-1 and C-3, whereas 6-CH3BP reacts competitively at C-1 and C-3, as well as at the 6-CH3 position.

Substitution of l-leucovorin for d,l-leucovorin in the rescue from high-dose methotrexate treatment in patients with osteosarcoma

Studies in which high-dose methotrexate (HDMTX) is used for the treatment of osteosarcoma have utilized commercial formulations of d,l-leucovorin (leucovorin calcium) for rescue from potential methotrexate (MTX) toxicity. These formulations are racemic mixtures containing equal amounts of d and l isomers of leucovorin. All of the available data indicate that the l isomer is the pharmacologically active diastereomer. A clinical study was conducted to determine if l-leucovorin was as safe and efficacious as d,l-leucovorin in the rescue of patients with osteosarcoma who were treated with HDMTX (12.5 g/m2 over 6 h). Because d,l-leucovorin consists of equal proportions of d and l isomers, l-leucovorin was administered at half the usual dose of d,l-leucovorin. In patients with delayed methotrexate excretion, l-leucovorin doses were escalated from 7.5 to 50 mg every 3 h until the MTX level was 0.3 mumol/l or less. Due to the low incidence of osteosarcoma, a control group of patients previously treated with d,l-leucovorin was utilized for comparison. Efficacy of l-leucovorin was determined by its ability to prevent HDMTX-associated toxicity. Demographic and clinical toxicity data from three patients who received 22 courses of MTX rescued with l-leucovorin were compared with data from six patients who had received 42 MTX courses rescued with d,l-leucovorin. Some liver function abnormalities and leukocyte elevations were found in both groups and were attributed to MTX administration. No clinical toxicity attributable to l-leucovorin was observed. l-Leucovorin in half the d,l-leucovorin dose was (equally) effective as a rescue treatment.

Chlorotrifluoroethylene trimer and tetramer are inducers of the CYP4A subfamily

Male Wistar albino rats were treated for a 7 day period with equimolar doses of the trimer and tetramer oligomers of chlorotrifluoroethylene (CTFE), resulting in significant hepatomegaly for both compounds. In addition, both trimer and tetramer significantly induced the peroxisomal beta-oxidation of fatty acids as assessed by increases in palmitoyl-coenzyme A (CoA) oxidation, thus confirming these oligomers as peroxisome proliferators. Consistent with these conclusions, both trimer and tetramer increased the hydroxylation of lauric acid indicating that the CTFEs were inducers of the CYP4A subfamily, a conclusion further supported by substantial increases in the steady-state levels of the cognate CYP4A1 mRNA as determined by northern blotting. The liver appeared to be more susceptible to induction than the kidney and the CTFE tetramer was more potent than the trimer. These results are discussed with respect to both the differential hepatotoxicity, and biotransformation/disposition of the two polyhalogenated oligomers.

Neuroendocrine and neurochemical responses to novelty stress in young and old male F344 rats: effects of d-fenfluramine treatment

To understand some of the mechanisms underlying the neuroendocrine and neurochemical changes associated with aging, we administered the serotonin [5-hydroxytryptamine (5-HT)] releaser and reuptake inhibitor d-fenfluramine (d-FEN; 0.0, 0.2, or 0.6 mg/kg/day, p.o) for 30-38 days to young (4 months) and old (22 months) F344 male rats. Rats were stressed by placement into a novel open field (OF) for 20 min before sacrifice. Control animals were sacrificed immediately upon removal from their home cage (HC). Old rats exhibited less (p < 0.05) exploratory behavior than young rats, which was not altered by treatment with d-FEN. Old HC rats also had higher (p < 0.05) basal plasma levels of adrenocorticotropic hormone (ACTH) and prolactin (PRL) than young HC rats. Old OF rats showed higher (p < 0.05) levels of ACTH and corticosterone (CORT) than young OF animals. A stress-induced increase in PRL secretion was not observed in old rats. Subchronic low-dose d-FEN normalized the enhanced ACTH and CORT responses of old animals to novelty. In addition to these endocrine changes, stress-induced increases in medial frontal cortex (MFC) dopamine (DA) and norepinephrine (NE) turnover also were observed. The increase in NE turnover was greater (p < 0.01) in old than in young rats. d-FEN treatment blocked the stress-induced increase in MFC NE but not MFC DA turnover in both young and old rats. These data support a role for 5-HT and/or NE in some age-related neuroendocrine perturbations and suggest that increased 5-HT neurotransmission can normalize the hyperactivation of the hypothalamo-pituitary-adrenal axis of old male rats.

The developmental pattern of rabbit brain insulin and insulin-like growth factor receptor expression

To examine the effect of development on rabbit brain insulin and insulin-like growth factor (IGF) receptor expression, we characterized and quantitated receptor mRNAs by Northern blot analysis and affinity-labeled ligand bound receptors by SDS-PAGE and autoradiography. At various stages of development ranging from 23 to 30 day gestational (term approximately 31 days), 1 to 10 day postnatal ages and the adult, no change in the whole brain insulin receptor mRNA (7.0, 6.0 and 5.5 kb) and affinity-labeled receptor protein (approximately 125 kDa) levels was observed. The IGF-I receptor mRNA (11.5, 6.5 and 4.5 kb) and affinity-labeled receptor (approximately 125 kDa) protein levels declined during the neonatal stages of development. In the case of the IGF-II receptor, while the mRNA levels (9.0 and 4.5 kb) remained constant, the corresponding affinity-labeled receptor protein (approximately 230 kDa) declined with maturation. We conclude that a differential regulation of brain insulin, IGF-I and IGF-II receptor expression occurs during development.

Detection and comparison of DNA adducts after in vitro and in vivo diesel emission exposures

Development of methods to evaluate certain classes of polycyclic aromatic compounds (PAC) detected in complex mixtures to which humans are exposed would greatly improve the diagnostic potential of 32P-postlabeling analysis. Identification of DNA adduct patterns or specific exposure-related marker adducts would strengthen associations between observed DNA adducts and exposures to different environmental pollutants (e.g., kerosene, cigarette smoke, coke oven, and diesel). We have compared diesel-modified DNA adduct patterns in various in vitro and in vivo rodent model systems and compared them to DNA reactive oxidative and reductive metabolites of 1-nitropyrene. The formation of nitrated polycyclic aromatic hydrocarbon (nitrated PAH) DNA adducts, derived from the metabolism of diesel extract constituents, was enhanced relative to other PAH-derived DNA adducts via xanthine oxidase-catalyzed nitroreduction. These adducts were detectable only by the butanol extraction version of the postlabeling analysis. Five major DNA adducts were detected in human lymphocytes treated in vitro with diesel extract. A major adduct detected in human lymphocytes treated in vitro with diesel extract comigrated with a major adduct detected in lymphocyte DNA treated with benzo[a]pyrene (BaP) alone. Other adducts that co-migrated with the major BaP-derived adducts were detected in skin and lung DNA isolated from rodents topically treated with (50 mg) diesel extract and the major adduct detected in calf thymus DNA treated with rat liver S9 and diesel particle extract. Postlabeling of lung DNA isolated from rodents exposed via lung inhalation for 24 months to diesel combustion emissions resulted in the formation of a major nuclease-P1-sensitive DNA adduct that did not co-migrate with the major BaP-diol epoxide adduct.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of DNA adducts from exposure to complex mixtures in various human tissues and experimental systems

DNA adducts derived from complex mixtures of polycyclic aromatic compounds emitted from tobacco smoke are compared to industrial pollution sources (e.g., coke ovens and aluminum smelters), smoky coal burning, and urban air pollution. Exposures to coke oven emissions and smoky coal, both potent rodent skin tumor initiators and lung carcinogens in humans, result in high levels of DNA adducts compared to tobacco smoke in the in vitro calf thymus DNA model system, in cultured lymphocytes, and in the mouse skin assay. Using tobacco smoke as a model in human studies, we have compared relative DNA adduct levels detected in blood lymphocytes, placental tissue, bronchoalveolar lung lavage cells, sperm, and autopsy tissues of smokers and nonsmokers. Adduct levels in DNA isolated from smokers were highest in human heart and lung tissue with smaller but detectable differences in placental tissue and lung lavage cells. Comparison of the DNA adduct levels resulting from human exposure to different complex mixtures shows that emissions from coke ovens, aluminum smelters, and smoky coal result in higher DNA adduct levels than tobacco smoke exposure. These studies suggest that humans exposed to complex combustion mixtures will have higher DNA adduct levels in target cells (e.g., lung) as compared to nontarget cells (e.g., lymphocytes) and that the adduct levels will be dependent on the genotoxic and DNA adduct-forming potency of the mixture.