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DNA damage (alkaline filter elution) and sister chromatid exchange (SCE) frequencies were measured in lymphocytes of 39 welders and 39 controls. The welders showed a significantly higher rate of DNA single-strand breakages and significantly elevated SCE values. These results are not in accordance with those of a former study in which only DNA-protein cross-links were measured. The different results may be explained on the basis of different exposure levels for chromium(VI) and nickel. Both methods are not specific but sensitive enough to measure genotoxic damage after occupational exposure to chromium(VI) and nickel in the range of threshold values for the workplace on a collective basis. Additionally, the results indicate that DNA single-strand breakage and DNA-protein cross-links show different increases depending on the exposure levels for chromium and nickel.

In a clinical assessment for compensation of workers previously exposed to chlorinated naphthalenes, laboratory values demonstrated findings of liver dysfunction. Am. J. Ind. Med. 32:413–416, 1997. © 1997 Wiley-Liss, Inc.

The renal excretion of arylamines in occupationally exposed and nonexposed subjects was measured by a gas chromatography-electron capture detector method. Additionally, in the occupationally exposed persons hemoglobin adduct levels of arylamines were determined by a liquid chromatography-electrochemical detector method, together with the individual acetylator status. The aromatic amines aniline, p-toluidine, 2-naphthylamine, and 4-chloro-o-toluidine were detected in the urine of nonsmoking subjects who were not occupationally exposed to arylamines. Significantly higher concentrations of aniline, o-toluidine, m-toluidine, 2-naphthylamine, and 4-methyl-1,3-phenylenediamine could be observed in the urine of smoking control persons in comparison to nonsmokers. Comparison of smokers and nonsmokers in a group of workers primarily exposed to aniline and 4-chloroaniline revealed significant differences (P0.05) in the formation of 4-aminodiphenyl hemoglobin adducts and in the renal excretion of 2-naphthylamine. The slow acetylators in this group produced significantly more hemoglobin adducts of aniline and 4-chloroaniline than did the fast acetylators. In slow acetylators among the smoking workers there was a significant increase in the formation of 4-aminodiphenyl hemoglobin adducts and in the renal excretion of 4-chloroaniline and m-toluidine. The results indicate that there are influences of smoking habits and acetylator status on the levels of arylamine hemoglobin adducts as well as urinary arylamine concentrations. Hemoglobin adducts seem to be good parameters for monitoring aniline and 4-chloroaniline exposure at the workplace, especially if the acetylator polymorphism can be taken into account. 4-Aminodiphenyl hemoglobin adducts might be good parameters for monitoring individual smoking habits. The determination of urinary arylamine concentrations provides additional information concerning acute exposures to aromatic amines.

Blood samples were obtained from different populations exposed occupationally or by lifestyle habits to polycyclic aromatic hydrocarbons (PAH). DNA adducts were determined by 32P-postlabeling assay either in white blood cells (WBC) or lymphocytes. The level of DNA adducts ranged from 1.5 per 10(9) nucleotides in one of the control groups up to 7.1 per 10(9) nucleotides in one group of PAH-exposed workers. Comparison of the adduct thin layer chromatography (TLC) profiles revealed individual variation in both pattern and level of DNA adducts. Significant differences of adduct levels were detected between one group of PAH-exposed coke-oven workers and the corresponding control group. Only a weak influence of the smoking habits on the amount of adducts was detectable in occupationally exposed or unexposed individuals.

The lymphocytes of 25 hospital workers exposed to ethylene oxide and of a standardized control group were investigated for DNA damage (measured by alkaline filter elution) and sister chromatid exchange (SCE) frequencies. Additionally, the excretion of hydroxyethyl mercapturic acid (HEMA) in the 24-h urine of ten workers and ten control persons was determined. The peak levels of ethylene oxide in air during the first 8 min after opening of the sterilization unit were measured. Peak levels of ethylene oxide in the air of up to 417 ppm after opening of the sterilization unit were detected. In the alkaline filter elution assay we found significantly reduced elution rates in the exposed workers, indicating DNA-protein cross-links. The reduction of the elution rates through HVLP filters correlated significantly with the exposure classification (low, medium, high) (r = −0.45, P < 0.05) and the ethylene oxide peak level after opening of the sterilization unit (r = −0.42, P < 0.05). The SCE frequencies in the standardized control group were significantly elevated. With respect to (n = 78) historic control SCE values of our institute, the SCE values of the disinfectors were not significantly elevated (6.54 vs 6.27). The ethylene oxide-exposed workers did not have a greater percentage of high-frequency SCE cells. The mean HEMA concentration in the urine of the exposed workers was significantly elevated, but there were wide variations in HEMA concentrations and no correlation to ethylene oxide exposure. We conclude that the alkaline filter elution assay may be a sensitive parameter for monitoring the genotoxic damage in lymphocytes of ethylene oxide-exposed workers. Determination of the HEMA concentration in urine may be suitable for the differentiation between ethylene oxide-exposed and nonexposed groups, but not for individual biomonitoring. The result of the SCE determination indicates that the standardization of control groups with respect to sex, age, and smoking habit seems unsatisfactory. Therefore, it is recommended that in further studies control groups be constructed with respect to additional lifestyle factors. Additionally, enzyme polymorphisms — especially of glutathione transferase in the case of ethylene oxide exposure — should be taken into consideration and controlled.

Five different representatives (I-V) of a new class of bifunctional alkylating agents, the 4-aroyl-1-nitrosohydrazinecarboxamides ("nitrososemicarbazides"), were evaluated for their potential interaction with DNA and for their cytotoxic activity in vitro to O6-alkylguanine-DNA alkyltransferase-positive (Mer+) and -negative (Mer-) human cell lines. The HeLa MR cell line (Mer-) showed up to 20-fold higher sensitivity at IC50 (dose that inhibits colony formation by 50%) to agents I-V than did the HeLa S3 cell line (Mer+) in a colony-formation assay. These data were compared to those obtained by treatment of the two cell lines with carmustine, a currently used antitumor drug. In Mer+ cells comparable results to those with carmustine were obtained with compounds III, IV and V; in Mer- cells compounds I and II showed nearly the same effects as carmustine. Whether compounds I-V produce DNA strand breaks and/or DNA-protein cross-links was investigated using an alkaline filter elution technique. In this assay all compounds produced DNA single-strand breaks; no correlation could be detected between the strand breakage frequency and cytostatic, mutagenic and antitumor activity.

Different parameters of biological monitoring were applied to 26 benzene-exposed car mechanics. Twenty car mechanics worked in a work environment with probably high benzene exposures (exposed workers); six car mechanics primarily involved in work organization were classified as non-exposed. The maximum air benzene concentration at the work places of exposed mechanics was 13 mg/m3 (mean 2.6 mg/m3). Elevated benzene exposure was associated with job tasks involving work on fuel injections, petrol tanks, cylinder blocks, gasoline pipes, fuel filters, fuel pumps and valves. The mean blood benzene level in the exposed workers was 3.3 micrograms/l (range 0.7-13.6 micrograms/l). Phenol proved to be an inadequate monitoring parameter within the exposure ranges investigated. The muconic and S-phenylmercapturic acid concentrations in urine showed a marked increase during the work shift. Both also showed significant correlations with benzene concentrations in air or in blood. The best correlations between the benzene air level and the mercapturic and muconic acid concentrations in urine were found at the end of the work shift (phenylmercapturic acid concentration: r = 0.81, P0.0001; muconic acid concentration: r = 0.54, P0.05). In conclusion, the concentrations of benzene in blood and mercapturic and muconic acid in urine proved to be good parameters for monitoring benzene exposure at the workplace even at benzene air levels below the current exposure limits. Today working as a car mechanic seems to be one of the occupations typically associated with benzene exposure.

Sister chromatid exchange (SCE) values were determined in the lymphocytes of 24 oral cancer patients before therapy and in the lymphocytes of 24 control persons standardized with respect to sex, age and smoking habits. Oral cancer patients showed significantly elevated SCE values (mean 7.82 versus 6.42). In both groups the highest SCE values were found in the subgroups with the highest alcohol consumption. A significant correlation between SCE and gamma-glutamyltranspeptidase (GGT) values by Spearman correlation analysis was detected in the combined group (cancer patients and control persons) (n = 32, r = 0.40, P = 0.023). The SCE values in the oral cancer patients were weakly correlated (Pearson) to DNA adduct levels (n = 22, r = 0.39, P = 0.068) and DNA single-strand breakage frequencies (n = 12, r = 0.56, P = 0.054) in lymphocytes. The correlation (Pearson) between SCE values and DNA strand breakage values in lymphocytes was significant (n = 10, r = 0.67, P = 0.036) in smoking cancer patients. The increase of SCE values with respect to alcohol drinking habits underlines epidemiologic findings that alcohol is an important co-carcinogen in many cancers, especially in oral cancers. Because of the influences on SCE and adduct levels in lymphocytes, alcohol drinking habits should be controlled as broadly as possible in biomarker studies.

N 7-Phenylguanine, a base adduct possibly formed after arylation of DNA by benzene oxide, the first reaction metabolite during benzene metabolism, was synthesized in our laboratory and used as reference for the production and characterization of monoclonal antibodies. 2-Hydroxymethyl-7-phenylhypoxanthine, a molecule structurally similar toN 7-phenylguanine, was coupled by a linker molecule to different carrier proteins. The resulting conjugate was used to immunize BALB/c mice, the spleen cells of which were fused with mouse P3X63-Ag8.653 myeloma cells to obtain monoclonal antibodies. Several hybridoma lines were cultivated in defined media and characterized as to sensitivity and specificity by an enzyme-linked immunosorbent assay (ELISA). Competitive ELISA demonstrated that all antibodies showed a very high affinity forN 7-phenylguanine but had a lower affinity towards various other samples includingN 7-chlorophenylguanines andC 8-,N 2- andO 6-phenylguanine. As little as about 20 pgN 7-phenylguanine could be detected with one of the most sensitive antibodies, CE6/G11, with a colorimetric end point while the detection limit could be lowered to about 10 pgN 7-phenylguanine when a fluorescent end point was used. The detection limit of other methods used to determineN 7-phenylguanine so far is 10 ng for gaschromatography/mass-spectrometry and 1 ng for high-pressure liquid chromatography. Thus the use of specific monoclonal antibodies seems to be the most sensitive method for the detection ofN 7-phenylguanine.

Excretion of phenanthrene and its metabolites, 1–; 2–; 3–; 4– and 9–OH–phenanthrene after alkaline and acidic saponification of urine and faeces, has been studied in rats following oral, intraperitoneal and intrapulmonary application of phenanthrene. GC and GC/MS methods have been used as analytical techniques. In all cases 1,2-oxidation of phenanthrene was found to be the predominant pathway. Total excretion of 11–18% of the phenanthrene administered by the above routes was observed indicating the presence of water-soluble metabolites other than sulfates and glucuronides. Phenanthrene apparently is suitable for biologically monitoring polycyclic aromatic hydrocarbons. The reasons are: a) the large amounts of phenanthrene and its metabolites excreted in the urine within a period of 3 days following intrapulmonary (1.3%), intraperitoneal (2.9%), or oral (4.1%) administration of phenanthrene, respectively; b) varied metabolites are formed which can reflect qualitatively the regiospecific monooxygen...

The microbial or chemical degradation of lignin from untreated samples of beech wood dusts (Fagus silvatica) resulted in the release of different mutagenic responses in the Salmonella/mammalian plate incorporation assay. In the first experiment using chemical degradation of lignin, dust samples were pre-extracted using acetone-water; the lignin portions were degraded into simpler compounds which were further fractionated on a Sephadex-LH20 column. The compounds isolated from the second phase of Sephadex, representing substances with a 3–4 ring structure and/or those of the same molecular weight, were highly mutagenic towards Salmonella typhimurium TA100 in the presence of metabolic activation. These substances were also active to some extent in strain TA 1537 both in the presence and absence of Aroclor-induced rat liver homogenates. In contrast, no direct- or indirect-acting mutagenicity was found when testing with strains TA97 and TA98. Strain TA1535 responded positively only to direct-acting mutagens in the fraction tested. The mutagenic fraction was found to be toxic to the cells when tested in a histidine-rich medium. Repurification of this mutagenic fraction, using silica-gel column chromatography, revealed much higher mutagenic activity than the test material towards strain TA100. In the second pilot experiment, Phanerochaete chrysosporium and Chaetomium globosum, which are known for their ability to degrade lignin, were each incubated with wood dusts in a mixture of physiological saline and nutrient broth for either 3 or 30 days. Significant mutagenic activity was observed with the dust extract after incubation with Ph. chrysosporium but not with Ch. globosum which is a known degrader of beech lignin. These results are discussed regarding hypotheses on the carcinogenicity of beech wood dusts.

Bei den in der Bundesrepublik jahrlich neu anerkannten Berufskrebserkrankungen ist ein Anstieg von 95 Fallen im Jahre 1978 auf 530 im Jahre 1988 und auf 1785 im Jahre 2000 zu verzeichnen, in der ehemaligen DDR stieg die Zahl von 137 im Jahre 1978 auf 327 (ohne Wismut AG) im Jahre 1988. Seit Mitte der 90er Jahre bewegen sich die Zahlen im vereinigten Deutschland auf annahernd gleichem Niveau, wahrend die Zahl der insgesamt anerkannten Berufskrankheiten rucklaufig wurde. Das zur Zeit etwa jede dritte anerkannte Berufskrankheit eine Krebserkrankung ist, durfte sowohl der noch in den 70er Jahren verbreiteten Verwendung krebserzeugender Arbeitsstoffe wie auch der zunehmenden Aufklarung beruflicher Krebsursachen, nicht zuletzt aber der wachsenden Aufmerksamkeit der Arzteschaft zuzuschreiben sein. Dennoch besteht kein Zweifel an einer erheblichen Dunkelziffer. Als Ursache gilt vor allem die Schwierigkeit, verwertbare Arbeitsanamnesen nach oft jahrzehntelangem Abstand zwischen beruflicher Einwirkung am Arbeitsplatz und Krankheitsbeginn zu erheben. Nicht wenige Arbeitnehmer erkranken erst im Rentenalter.

Former East German uranium miners who are known to have been exposed to radon are estimated to be at high risk for lung carcinogenesis. Among these miners over 200 occupationally caused lung cancer cases are expected to occur each year, resulting in a total of 7,000-24,000 excess lung cancer cases in the coming years. It is still unknown whether there is a correlation between biomarkers and the exposure of the uranium miners to ionizing radiation that might enable us to trace those miners with high lung cancer risk. The primary aim of this pilot study was to test the possibility of performing a biomarker study in this unique cohort of former uranium miners in spite of several limitations that had to be taken into consideration when comparing them with healthy controls, such as old age, age-dependent diseases and potential confounding artefacts from dissimilar smoking patterns. The second aim was to test a range of biomarkers for DNA damage and inflammation in leukocytes and bronchoalveolar fluid for their ability to detect biological effects. In this cohort of miners we found an increased frequency of chromosomal aberrations in blood lymphocytes and an increased prevalence of both fibronectin and tumour necrosis factor alpha in the bronchoalveolar fluid.

Purpose: There is a high prevalence of G→T transversions of p53 in lung cancers of smokers. One study has reported a special “hotspot” mutation at codon 249 of p53 in lung cancers of former uranium miners. The aim of our study was to look for mutational spectra of p53 in former German uranium miners with lung cancers. Methods: We investigated 16 patients with lung cancer who had worked as uranium miners in Germany and 13 lung cancer patients without a mining history of the same region. By means of the polymerase chain reaction and sequencing we looked for mutations in exons 5–7 of the p53 gene. Results: We could not find any suggestion of hotspot mutations. The only G→T mutation in former uranium miners was detected in the only nonsmoker. In 3 patients (19% of the total) we found a codon 213/3 polymorphism. Conclusions: The results indicate that G → T transversions do not seem to be very common mutations in p53 in lung cancers probably caused by radiation. Therefore, p53 may be mutated early in lung cancer development if radiation exposure is a critical factor in carcinogenesis. In accordance with studies of thyroid cancer patients in the Chernobyl region, our results may indicate an overrepresentation of codon 213/3 polymorphism in p53 in radiation-caused cancers.

OBJECTIVES: To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, 32P postlabelling assay, measurement of sister chromatid exchange) in workers exposed to polycyclic aromatic hydrocarbons (PAHs). METHODS: 29 coke oven workers and a standardised control group were investigated for frequencies of DNA single strand breakage, DNA protein cross links (alkaline filter elution assay), sister chromatid exchange, and DNA adducts (32P postlabelling assay) in lymphocytes. Phenanthrene and pyrene metabolites were measured in 24 hour urine samples. 19 different PAHs (including benzo(a)pyrene, pyrene, and phenanthrene) were measured at the workplace by personal air monitoring. The GSTT1 activity in erythrocytes and lymphocyte subpopulations in blood was also measured. RESULTS: Concentrations of phenanthrene, pyrene, and benzo(a)pyrene in air correlated well with the concentration of total PAHs in air; they could be used for comparisons of different workplaces if the emission compositions were known. The measurement of phenanthrene metabolites in urine proved to be a better biological monitoring variable than the measurement of 1-hydroxypyrene. Significantly more DNA strand breaks in lymphocytes of coke oven workers were found (alkaline filter elution assay); the DNA adduct rate was not significantly increased in workers, but correlated with exposure to PAHs in a semiquantitative manner. The number of sister chromatid exchanges was lower in coke oven workers but this was not significant; thus counting sister chromatid exchanges was not a good variable for biomonitoring of coke oven workers. Also, indications for immunotoxic influences (changes in lymphocyte subpopulations) were found. CONCLUSIONS: The measurement of phenanthrene metabolites in urine seems to be a better biological monitoring variable for exposure to PAHs than measurement of hydroxypyrene. The alkaline filter elution assay proved to be the most sensitive biomarker for genotoxic damage, whereas the postlabelling assay was the only one with some specificity for DNA alterations caused by known compounds.

Die altersabhangige, organspezifische Kinetik von Zeilproliferation und Zellverlust wird bestimmt durch die Proliferationskompetenz der individuellen Zelle im Wechselspiel mit ihrer differenzierten Funktion, durch interzellulare Kommunikation, Einflusse der extrazellularen Matrix und der Gewebsstruktur, durch das humorale Mikromilieu unter Mitwirkung auto- und parakriner Faktoren und schlieslich durch ubergeordnete systemische humorale, hormonelle und zellulare Faktoren. Gegen dieses hierarchisch geordnete, nur durch kontinuierliche Interaktion zwischen extrazellularen Faktoren und deren zellularen Rezeptoren funktionierende balanzierte System sind Krebszellen auf mindestens einer Ebene refraktar. Sie gewinnen mit der malignen Transformation eine relative, in der Regel fortschreitende Autonomie gegen homoostatische Einflusse des Organismus bei gleichzeitigem Diffenzierungsverlust.

In lymphocytes of 12 oral cancer patients (and two control groups) the frequencies of DNA single-strand breaks and DNA-protein cross-linking were determined by alkaline filter elution. We found elevated DNA elution rates, which must be interpreted as an increased strand breakage frequency. There were significant correlations between the DNA strand breakage frequency and smoking habits. Using the 32P-postlabelling assay we determined the DNA adduct level in lymphocytes of 23 oral cancer patients (and two control groups). No significant influence of smoking habit on the DNA adduct level could be detected. There was a significant correlation between the DNA adduct level and the gamma-glutamyltranspeptidase (GGT) value, suggesting systemic influences of alcohol drinking habits on the adduct level.

A review of the impact of chlorinated biphenyls (PCBs) on reproduction is presented. PCBs are able to pass the placenta; accumulation in offspring is mainly achieved by breast feeding. Disturbances of fertility and embryotoxicity were detected in animals; teratogenicity without maternal toxicity was only observed in mice. In animal experiments disturbances of fetal and postnatal development were detected as well as in human studies. Neurotoxicity was observed even at low-level exposures in monkeys, which are most comparable to humans because of the development of the same clinical symptoms. Technical PCBs which are dominating in occupational and environmental exposure until now must be judged as toxic for reproduction: dermal exposure (especially in accidents) should be considered as an important route of exposure beside inhalation. Work to list possible PCB exposure risks and to develop ways to reduce these risks are necessary now.

Investigations with [14C]benzene indicate the formation of base adducts in vivo. Experiments to separate adducts from urine of [14C]benzene-exposed rats suggest the excretion of eight labeled compounds different from benzene metabolites. In order to obtain information about their structure we synthesized N7-, O6-, C8- and N2-phenylguanine. With regard to their chromatographic properties we compared these phenylguanines with products obtained by alkylation of guanine by metabolites of unlabeled and 14C-labeled benzene in vivo with HPLC with UV detection and liquid scintillation counting. Furthermore GC/MS and ELISA techniques were used to detect N7-phenylguanine. Phenylguanines could not be identified in collected DNA fractions. The labeled compounds detected in urine of [14C]benzene-exposed rats also showed deviations from the HPLC elution patterns of our reference substances. Even N7-phenylguanine, formerly suspected to be a urinary metabolite of benzene in the rat, could not be detected with these refined HPLC methods. With GC/MS a compound was found in trace amounts in concentrated rat urine samples, which had a similar fragmentation pattern to N7-phenylguanine. These data could not be confirmed by a sensitive immunological assay (ELISA). No N7-phenylguanine was detected in purified rat urine samples. The results suggest the excretion of a hydroxylated phenylguanine which may be formed in liver or bone marrow DNA by highly reactive hydroxylated intermediates. The OH group might be lost because of the high temperatures during GC/MS measurements. A hydroxy group at the phenyl-ring of N7-phenylguanine will cause other elution properties in HPLC compared to N7-phenylguanine.

An investigation was made of 17 patients with multiple myeloma using the method of alkaline filter elution for the detection of DNA damage and the determination of sister chromatid exchange (SCE) frequency in peripheral lymphocytes during a course of chemotherapy with melphalan and prednisone. We were able to detect elevated SCE frequencies in pretreated patients that approximately doubled during the therapeutic cycle. An appreciable level of DNA cross-linking was detected by alkaline filter elution; DNA cross-linking scarcely increased during a course of chemotherapy. The increase in the SCE frequency during the first therapy cycle was even greater in the case of patients with newly diagnosed multiple myelomas. The results obtained by alkaline filter elution and measuring SCE frequencies suggest that these techniques are suitable as methods in molecular epidemiology, especially if applied to persons who are chronically exposed to cytostatic drugs. Whether or not the methods could be valuable in evaluating therapy response needs further investigation.

Between 1982 and 1990 seven cases of bladder cancer were detected in a group of 49 workers who were synthesising chlordimeform from 4-chloro-o-toluidine. Latency periods ranged from 15 to 23 years. The incidence of bladder tumours in this group was significantly higher than that of the cancer registers of the former GDR, Saarland, and Denmark by factors of 89.7, 53.8, and 35.0 respectively. This provides further evidence that monocyclic aromatic amines such as 4-chloro-o-toluidine may be carcinogenic in humans.

In biological effect monitoring the alkaline filter elution is a suitable method to detect DNA strand breakage and cross-linking in peripheral blood lymphocytes. We applied this method to three groups of workers occupationally exposed to carcinogens: n = 39 welders with exposure to chromium and nickel, n = 20 female shoemakers with exposure to benzene and n = 25 disinfectors in hospitals with exposure to ethylene oxide. In comparison to standardised control groups our results must be interpreted as indicating an increased rate of DNA cross-linking in welders and disinfectors whereas the female shoemakers showed an increased rate of DNA strand breakage. The differences between the results of the exposed groups and the stratified control groups were significant in most cases. We could reexamine 6 shoemakers 4 months after cessation of exposure to benzene; at this moment the results were indicating a clear decrease of the DNA strand breakage. Therefore the method of alkaline filter elution seems to be a valuable tool in biological effect monitoring of groups occupationally or environmentally exposed to carcinogens, especially if the exposure is low, but persistent over a long period.

Peripheral lymphocyte DNA damage as measured by the method of alkaline filter elution and the frequency of sister chromatid exchange (SCE) in lymphocytes was investigated for a group of 20 female workers of a shoemaking plant who were exposed to benzene and toluene, primarily below the German threshold limit value of 5 and 100 p.p.m. respectively; the results were compared with those from a control group. In the female workers significantly raised (P less than 0.05) SCE values were found. The relative DNA elution rate through polycarbonate filters was significantly increased (P less than 0.001). The elution rate through polyvinylidene fluoride (HVLP) filters showed a tendency to increase (P = 0.052), which must be interpreted as indicating increased DNA strand breakage. The SCE rates of the female workers were significantly correlated (P less than 0.01) with the relative DNA elution rate through HVLP filters. There was no correlation with the actual benzene and toluene uptake measured by personal air monitoring. Four months after cessation of work, DNA strand breakage decreased significantly (P less than 0.05) in blood samples of six reinvestigated female workers.

Fur eine wissenschaftlich begrundete Abschatzung beruflicher Krebsrisiken sind in den vergangenen Jahrzehnten weltweit neue Losungsansatze gesucht worden. Mit der Einsicht, das die damit verbundenen Schwierigkeiten mit herkommlichen Mitteln nicht zu uberwinden sind, richtete sich die Aufmerksamkeit auf neue Methoden der biologischen Analytik. Zwei Losungswege zeichnen sich heute ab. Bei dem ersteren beruht die Risikokalkulation auf der Messung der internen Belastung des Organismus durch ein Umweltkanzerogen bzw. auf der Gewinnung von Informationen uber die effektive Gewebedosis unter Berucksichtigung ihrer zeitlichen Schwankungen. Der 2. Weg fuhrt zur Abschatzung individueller Krebsrisiken auf der Basis quantitativer Bestimmungen sog. genotoxischer Effekte von Karzinogenen auf verschiedene Arten von Zellen. Die Kombination der Methoden, die heute zur Quantifizierung von Belastung und Beanspruchung des Organismus zur Verfugung stehen, mit denen der analytischen Epidemiologie fuhrte zum modernen Konzept einer molekularen Epidemiologie, die sich neben der Risikoabschatzung die Uberwachung von Risikopopulationen uber ein sog. Dosenmonitoring, die Fruherkennung neuer Risiken und die Klarung der Ursachen individuell schwankender Susceptibilitat gegenuber Kanzerogenen zum Ziel gesetzt hat.

Tetrachloroethene concentrations in blood and trichloroacetic acid concentrations in urine were determined--primarily over the course of a week--for 29 persons living in the vicinity of dry-cleaning shops. The mean levels of tetrachloroethene increased during the week. In some neighbours concentrations were exceeding the German biological threshold limit value for tetrachloroethene (1000 micrograms/l blood), persisting over the whole week in one case. The concentrations of tetrachloroethene in blood depended on the floor and the construction type of the building where these people were living, but not of the type of system used in the dry-cleaning shops. 5 of 12 dry-cleaners were found to have tetrachloroethene levels exceeding the German biological threshold limit value, some of them by a considerable amount.

A total of 39 electric welders exposed to chromium and nickel were compared with 18 controls standardized for age, smoking habits and sex with respect to the frequency of sister chromatid exchange (SCE) and of DNA strand breakage and cross-linking (measured by the method of alkaline filter elution) in their blood lymphocytes. A significant correlation was found between the frequency of SCE and of individual DNA strand breakage and the concentration of chromium in the urine. Less DNA from the welders than from the control group was eluted through the two filter types used (polycarbonate and polyvinylidene fluoride filters). This must be interpreted as resulting from the presence of DNA-protein cross-links, which has the secondary effect of leading to a relative reduction in the measurable frequency of strand breakage amongst the welders. The present results are in good agreement with in vitro and in vivo investigations that confirm the importance of DNA-protein cross-links for the carcinogenic effect of chromium.

Five experimental anti-leukemic agents, 1-(2-chloroethyl)-4-arylacyl-1-nitrososemicarbazides, were synthesized and tested for genotoxicity in the Salmonella/mammalian microsome assay. No strong mutagenic activity could be detected when tested with the S. typhimurium TA98. A clear dose-dependent base-pair-substitution mutagenic activity was observed with each compound when the tester strain TA100 was used with or without metabolic activation. The genotoxicity of the unsubstituted substance was similar to that of the known mutagenic cytostatic drugs, lomustin and carmustin, and was stronger than the mutagenicity of each substituted derivative.

PAH are a class of potent carcinogens which are widely distributed to the human environment. Accordingly, regulations have set limits to their concentration in water and foodstuffs and recommendations for maximum concentrations in ambient air have been suggested. To control the actual concentrations of PAH in various matrices, environmental monitoring programs have been initiated in many countries and a bulk of data has been collected so far. However, not that many efforts have been made to study the fate of PAH in the human body, although metabolic studies with mammals have evidenced that PAH are primarily converted into epoxides, phenols and trans-dihydrodiols which subsequently may be conjugated to glucuronic and sulfuric acid or to glutathione. They are finally excreted by the faeces and the urine. Preliminary studies, however, have shown that there are striking individual variations in the isozyme pattern responsible for the PAH-oxidation in man. As a base for future biological monitoring programs which aim to estimate or predict the individual risk caused by occupational exposition and metabolic activation, we have studied the fate of 5 different PAH in rats following various modes of application (oral, intraperitoneal, intratracheal and intrapulmonary). To this end metabolites have been analysed by GC/MS as phenol ethers in urine and faeces after acidic/alkaline saponification, a specific cleanup and derivatization with diazomethane. This method allows the measurement of free primary metabolites and conjugates with glucuronic and sulfuric acid, whereas gluthathione conjugates have not yet been regarded.

Desinfektionsmasnahmen im Krankenhaus dienen dem Ziel, die unmittelbare Umgebung des Kranken so weit von Krankheitserregern zu dekontaminieren, das keine Infektionsgefahr mehr von ihr ausgeht. Dabei sind Keimreduktionen von 3–5 log anzustreben. Elementar, und doch immer wieder in Erinnerung zu rufen, sind 2 grundlegende Voraussetzungen erfolgreicher Desinfektion, namlich ausreichende Konzentration des verwendeten Wirkstoffs und ausreichende Einwirkzeit. Das unter gegensinniger Veranderung beider Faktoren gleiche Konzentrations-Zeit-Produkte erreicht werden konnen, gibt uns die Chance einer Navigation zwischen Skylla und Charybdis. Einerseits mus den praktischen Schwierigkeiten einer sachgerechten Desinfektion uber hinreichend lange Zeit in der Klinik Rechnung getragen werden. Andererseits sind einer beliebigen Ernahrung der Wirkstoffkonzentration nicht nur vom behandelten Material her, sondern v.a. im Hinblick auf toxische Effekte bei Patienten und Personal Grenzen gesetzt, die uns zur Zeit deutlicher und unangenehm bewust werden.

Comparative investigations with synthetic N7-phenylguanine were carried out to clarify whether this compound is eliminated via the urine of rats as a benzene-derived nucleic acid adduct. As sensitive methods for detecting trace amounts of the compound, gas chromatography-mass spectroscopy, high performance liquid chromatography, and two immunoassays (enzyme-linked immunosorbent assay and fluoroimmunoassay) with appropriate monoclonal antibodies were used. The results indicate the excretion of several benzene-related guanine adducts slightly different from N7-phenylguanine that may possibly be hydroxylated. These adducts differ also from (O6-, N2- and C8-phenylguanine, respectively.

Male Wistar rats (240–320 g b. wt.) were partially (2/3) hepatectomised and immediately thereafter exposed to inhalation over 28 h of vinyl chloride monomer (VCM) at concentrations of 0, 50, 125, and 500 ppm. An investigation was also performed in which, following partial hepatectomy, rats of 130–150 g b. wt. were infused by the caudal vein over 28 h with As2O3 (AT) at concentrations of 0, 1, 2, and 10 mg/ml. The total volume of the infusion was 16.8 ml. Following treatment, the liver was removed and investigations were made of proliferative activity in the tissue. With preparations from VCM-treated animals, investigations were made of the mitotic index (histologically), the 3H-thymidine index (autoradiographically), and the incorporation of 3H-thymidine in DNA (using liquid-scintillation counting). Further investigations were made of DNA synthesis in nuclei of these tissues by impulse-cytophotometry determining the proportions of cells in S-phase to those in G1. Incorporation of 3H-thymidine and mitotic activity was also determined using tissue from AT-treated animals. The tissue alkaline phosphatase activities in liver preparations both from VCM- and AT-treated animals were also measured. In all measured parameters, an increase was observed over values found in controls and those increases were dose-related. The results indicate that administration of VCM or AT leads to stimulation of cell proliferation in regenerating rat liver. However, increase of alkaline phosphatase activity could not be referred to preferential effects of VCM and AT on endothelial cells. As shown by histochemical investigations, the alkaline phosphatase activity was localised mainly in bile-duct canaliculi — not in sinusoids.

From preliminary experiments it was known that radiolabelled benzene and some of its metabolites during its metabolic activation process produce different in vitro DNA-phenyladducts in mitoplasts. As we reported previously at least one of these adducts, N-7-phenylguanine, is excreted in the urine of rats in measurable amounts, probably through an excision-repair mechanism after an inhalation experiment. Now we found, after i.p. application of benzene in the urine of rats, a compound separated by cation-exchange chromatography that behaves like a synthesized N-7-phenylguanine reference substance with respect to its retention index and the UV-absorption. This finding could be confirmed by HPLC-measurements with reversed-phase carrier materials. Silylation and gas chromatographic/mass spectrometric (GC/MS) separation of the fraction, which contains the phenylguanine, revealed that these fractions contain further phenyl adducts. Furthermore we studied the time-dependent excretion of the DNA-base adduct. Surprisingly the excretion dropped to zero on the fourth day and showed a new increase thereafter.

The chromosome-damaging effects of cigarette sidestream (SS) and mainstream (MS) smoke condensates and a mixture of these were compared in 8-week-old NMRI mice by intraperitoneal administration. Each filtered commercial brand of cigarette was smoked by a smoking machine under the standard conditions, and the separately collected SS and MS smoke condensates were extracted with acetone/methanol as described elsewhere. The extracts were tested before and after treatment of animals with an enzyme inducer (Aroclor 1254) or inhibitor (Metyrapone). Increased formation of micronuclei within polychromatic erythrocytes (PCEs) of femural bone marrow 30 h after injection of the extracts was regarded as being due to a clastogenic effect. Regardless of the type of smoke extract injected, the increased formation of micronuclei was found to be dose dependent. The SS smoke condensate induced approximately 29% more micronuclei than the MS smoke condensate, the difference being significant (P less than 0.01). The overall clastogenicity of a 1:1 mixture of SS and MS smoke condensates was not substantially different from the activity of either SS or MS smoke condensate alone. Pretreatment of animals with Aroclor clearly enhanced the differences between the number of micronucleated PCEs caused by SS versus MS smoke condensate; SS smoke condensate induced 50% more micronuclei than did MS smoke condensate (P less than 0.001). Pretreatment of mice with Metyrapone did not modify appreciably the induction of micronuclei by either type of smoke. These results are discussed with reference to our previous data involving inhalation experiments and the recent issue of passive smoking.

The development of Vaccinia-virus plaques on the chorioallantois of embryonated eggs was studied under the influence of active cyclophosphamide metabolites. The viruses were inoculated on the 9th or the 13th incubation day. Cyclophosphamide was injected in doses of 62.5--500 mug in 0.2 ml NaCl into the yolk sac either 7 hrs after the virus inoculation or 3, 6, or 9 hrs in advance. The plaque development was not influenced when cyclophosphamide was given after the virus inoculation. But in treating the embryos before the infection a decrease dependent on the dose in the number of embryos with recognizable plaques occurred. This decrease was more marked with cyclophosphamide treatment 6 or 9 hrs, than with cyclophosphamide treatment 3 hrs before the virus inoculation. When the embryos were inoculated on the 13th day and treated with cyclophosphamide 9 hrs in advance, the mean effective dose was 316 mug/egg. The range of effective doses corresponds with that of the inhibitory effective doses of cyclophosphamide on transplantation tumors grown on the chorio-allantois of embryonated eggs.

The urinary and faecal excretion of chrysene and its phenolic metabolites after oral, intraperitoneal, intratracheal, and intrapulmonary administration to rats have been studied by means of gas chromatography/mass spectrometry. The metabolite profile was found to depend on the mode of excretion and on the route of administration. In all cases the oxidation of chrysene in the 1,2- or 3,4- position predominates, whereas oxidation in the 5,6-position (K-region) seems be a minor pathway.

The urinary and faecal excretion of pyrene and 1-hydroxypyrene after oral (53.4%), intraperitoneal (3.1%), intratracheal (30–37%) and intrapulmonary application (0.003%) to rats has been determined by means of gas chromatography/mass spectrometry and the excretion rates were found to depend on the mode of application. With regard to the low urinary excretion rates, 1-hydroxypyrene seems not to be very suitable as a biological marker for PAH exposure to man.

Correlations between exposure to vinyl chloride and the development of malignant tumors in the liver have been known since 1974 and have been confirmed by many an experimental investigation. Based on the evaluation of mortality statistics from nine different countries an increased incidence of malignant tumors of the lung, the gastrointestinal tract, and the central nervous system (CNS), and of malignant lymphomas is documented in connection with exposure to vinyl chloride. Statistically significant increases, however, are only found in the incidence of malignant liver tumors. Metabolism and toxicology of vinyl chloride are discussed in detail.