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O Holz

Publications and source records attributed to O Holz.

34 records · Page 2Linked to original sources
PubMed2000

The effect of repeated ozone exposures on inflammatory markers in bronchoalveolar lavage fluid and mucosal biopsies.

The aim of this study was to investigate the cellular and biochemical events associated with repeated exposures to ozone. Twenty-three healthy subjects underwent single exposures to 200 ppb ozone and to filtered air (FA), as well as repeated exposures to 200 ppb ozone on 4 consecutive days, each for 4 h of intermittent exercise. Bronchoalveolar lavage was performed and mucosal biopsies were taken 20 h after the single or the last of the repeated exposures. As compared with FA, the single exposure to ozone caused a decrease in FEV(1), an increase in the percentages of neutrophils and lymphocytes, the concentrations of total protein, IL-6, IL-8, reduced glutathione, urate, and ortho-tyrosine in BAL fluid (BALF), but no changes in the cellular composition of biopsy. After the repeated exposure, the effect on lung function was abolished and differential cell counts in BALF were not significantly different from those after FA. However, the concentrations of total protein, IL-6, IL-8, reduced glutathione, and ortho-tyrosine were still increased. IL-10 could only be detected in BALF after repeated ozone exposures. Furthermore, macroscopic scores for bronchitis, erythema, and hypervulnerability of airway mucosa were increased, as well as numbers of neutrophils in bronchial mucosal biopsies. Our data demonstrate that airway inflammation persists after repeated ozone exposure, despite attenuation of some inflammatory markers in BALF and adaptation of lung function.

Adult↗
PubMed1999

Sequentially induced sputum in patients with asthma or chronic obstructive pulmonary disease.

It has been demonstrated that consecutive samples of induced sputum may differ with respect to cellular composition. The aim of this study was to compare two sequential sputum samples in patients with chronic obstructive pulmonary disease (COPD) and asthma with different severity. Two sputum inductions were performed 30 min apart and processed separately in healthy subjects (n=11), patients with moderate to severe COPD (n=10), asthmatics treated with beta2-agonists alone (group 1, n=11), inhaled steroids (group 2, n=12) or systemic steroids (group 3, n=7). In healthy subjects and asthma group 2, percentages of neutrophils decreased significantly between the two sputum inductions but did not change in COPD and asthma group 3. Percentages of eosinophils did not change significantly in any group of patients. Concentrations of interleukin (IL)-8 decreased significantly in the control group and asthma groups 1 and 2 but not in asthma group 3 and the COPD group. These data demonstrate differences in sputum composition between two consecutive samples which were most pronounced in healthy subjects. Therefore, pooling of sputum samples may affect the results, particularly in healthy subjects, in contrast to subjects with more severe asthma or chronic obstructive pulmonary disease. These findings may be suggestive of differences in the distribution of inflammation along the airways between distinct airway diseases.

Administration, Inhalation↗
PubMed1999

Ozone-induced airway inflammatory changes differ between individuals and are reproducible.

To study whether the individual inflammatory response to ozone was reproducible, dose-dependent, and time-dependent, we performed two exposures to 250 ppb ozone, one to 125 ppb and one to filtered air, each for 3 h of intermittent exercise and separated by at least 1 wk. Twenty-one healthy and 15 asthmatic subjects participated in the study. One hour after the two exposures to 250 ppb ozone we observed a mean increase in sputum neutrophils of 17.9 and 17.9% in healthy and of 20.3 and 15.2% in asthmatic subjects (p < 0.05 each). Twenty-four hours after exposure, the respective values were 11.9 and 14.8%, and 9.1 and 16.1% (p < 0.05 each). In the whole group of subjects, individual changes in the percentage of neutrophils were significantly correlated between the two exposure days 1 h (r = 0.87, p < 0.001; intraclass correlation coefficient [Ri] = 0.86) as well as 24 h (r = 0.79, p < 0.001; Ri = 0.71) after exposure. The percentages of lymphocytes were increased 24 h after exposures (all subjects combined: p < 0.05). The decrease in FEV1 in both groups (p < 0.01), was also reproducible (r = 0.77, p < 0.001), but there were no correlations between changes in sputum parameters and lung function. Exposure to 125 ppb ozone caused a small increase (p < 0. 05) in the percentage of neutrophils in asthmatic subjects and in the concentrations of interleukin-8 in both groups combined. Our data demonstrate that inflammatory and lung function responses to ozone differ between individuals and are reproducible but not related to each other. Therefore, these responses appear to represent two independent factors underlying the airway response to ozone.

Adult↗
PubMed1998

Changes in sputum composition during sputum induction in healthy and asthmatic subjects.

BACKGROUND: Induced sputum is increasingly used to characterize the cellular and biochemical composition of the airways. OBJECTIVE: We studied whether the composition of induced sputum is different between samples obtained sequentially during one sputum induction. METHODS: Subjects with mild asthma (n=7) or healthy subjects (n=6) produced sputum during and after three consecutive 10 min periods of hypertonic saline inhalation. Samples were analysed separately for the three periods. To determine the reproducibility of the cellular composition, sputum induction was repeated on another two days. RESULTS: The mean percentage of neutrophils decreased significantly (P<0.01) during sputum induction in asthmatic (36.9, 29.8, 16.3%) and healthy subjects (43.6, 17.2, 18.0%). Correspondingly, percentages of macrophages increased and percentages of eosinophils were 4.9, 3.5, and 3.7% in the asthmatic and 0.6, 0.7, and 0.5% in the healthy subjects, without significant change over the three periods; mean eosinophil numbers were significantly higher in the subjects with asthma (P< 0.05). Reproducibility of percentage cell counts did not markedly depend on sampling periods in terms of coefficients of variation. The concentration of eosinophil cationic protein decreased in both groups during sputum induction (P<0.01), geometric mean values being 579, 143, 57.4 microg L(-1) in the asthmatic and 130, 47.3, 28.4 microg L(-1) in the healthy subjects. Similar changes were seen for lactate dehydrogenase. CONCLUSION: The separate analysis of induced sputum from three consecutive sampling periods of a single induction procedure demonstrated significant changes in their cellular and biochemical composition, both in healthy and mild asthmatic subjects.

Administration, Inhalation↗
PubMed1998

Changes in sputum composition between two inductions performed on consecutive days.

BACKGROUND: Sputnum induction is a non-invasive method for obtaining cellular and biochemical material from the airways and appears to be particularly suited for repeated testing. However, it has not been clarified whether repeated inductions lead to a change in sputum composition. The aim of this study was to compare induced sputum results between two inductions performed 24 hours apart. METHODS: Ten subjects with mild asthma and 19 healthy subjects were included. Sputum was obtained during three consecutive 10 minute periods of hypertonic saline inhalation. Samples were analysed separately for the three inhalation periods. Corresponding pooled values were computed, taking into account total cell numbers of each inhalation period. RESULTS: In the three consecutive inhalation periods mean (SE) percentages of neutrophils increased from 29.2 (4.2)%, 22.0 (4.6)% and 14.5 (2.9)% on day 1 to 43.1 (5.3)%, 34.8 (5.5)% and 25.7 (5.3)% on day 2 in healthy subjects and from 21.3 (4.3)%, 24.1 (5.9)% and 15.9 (3.7)% to 35.9 (6.9)%, 30.7 (7.1)% and 31.8 (6.5)% in asthmatic subjects. This parallel shift corresponded to a mean (95% CI) increase in the pooled percentages of neutrophils of 17.4 (11.6) to 23.3)% in healthy and 14.6 (1.2 to 28.0)% in asthmatic subjects. In contrast to neutrophils, the percentage of macrophages decreased from day 1 to day 2, while eosinophil and lymphocyte percentages did not change significantly. CONCLUSION: These results suggest that the induction procedure itself causes a change in the composition of sputum detectable after 24 hours. This effect has to be taken into account when repeated sputum induction is performed.

Adult↗
PubMed1995

Reproducibility of basal and induced DNA single-strand breaks detected by the single-cell gel electrophoresis assay in human peripheral mononuclear leukocytes.

The aim of the reported study was to investigate the reproducibility of the single-cell gel electrophoresis (SCGE) assay in the determination of DNA single-strand breaks (SSBs) and to estimate the statistical requirements when the SCGE assay is used for the detection of genotoxicity in humans. In human peripheral mononuclear leukocytes (PMLs), we repeatedly measured the rate of SSBs after in vitro incubation of cells for 1 h at 4 degrees C in phosphate buffered saline (PBS, basal) or 10 microM or 50 microM H2O2 (induced). Intra-assay variation was determined from cryopreserved PMLs of a single donor. To assess intrasubject and intersubject variation, PMLs of ten healthy, nonsmoking subjects (aged 19-37 years) were tested 5-9 times. Cryopreserved cells revealed a mean coefficient of variation of 18% (PBS) and 7%-9% (H2O2). There were statistically significant differences between individuals in the rate of SSBs after incubation in PBS (P < 0.01), 10 microM H2O2 (P < 0.001), and 50 microM H2O2 (P < 0.001). The range of interindividual variability was 26% for basal and 12%-13% for induced SSBs, and the coefficient of intraindividual variation was 18%-72% (PBS) and 7%-23% (H2O2). Neither basal nor induced rates of DNA damage were related to gender or age. Estimates of the minimum detectable effects were based on these observed sources of variability (power 90%, level of significance 5%, assumed sample size 50). With two different groups, a difference of 31% in basal SSBs or 12% in induced SSBs would be detectable. Repeated measurement within one group could detect a difference of 26% in basal and 9% in induced SSBs. In summary, the SCGE assay appears to be suitable for the detection of single-strand breaks, e.g., in biomonitoring or environmental medicine, and the statistical requirements could be derived from our analysis of the sources of variability.

Adult↗
PubMed1995

Differences in basal and induced DNA single-strand breaks between human peripheral monocytes and lymphocytes.

The aim of this study was to compare the susceptibility of peripheral monocytes and lymphocytes to oxidant-induced DNA single-strand breaks (SSB). DNA damage was assessed by the alkaline single-cell gel electrophoresis (SCGE) assay. Total peripheral mononuclear leukocytes (PML), PML enriched in lymphocytes and PML enriched in monocytes were used. The basal rate of SSB was measured after in vitro incubation of cells for 1 h in phosphate-buffered saline, and the induced rate after incubation in 10 microM or 50 microM H2O2. Incubation was performed at 4 degrees C to limit the possible influence of DNA repair. Lymphocyte-enriched PML were obtained after adhesion of the monocytes to tissue-culture treated plastic, and monocyte-enriched PML by removal of monocytes from the plastic through trypsin. In all samples, cell differentiation was performed using an immunofluorescence technique with antibodies against T- and B-lymphocytes and cytospin preparations. The rate of SSB was determined by visual scoring according to 6 predefined categories of DNA damage and was expressed as mean score (range 0-500) per 100 cells. There was a linear relationship between the percentage of lymphocytes in the samples and the basal rate of SSB (p < 0.001, slope 0.67 score units per %). The same was true for induced DNA damage after incubation in 10 microM H2O2 (p < 0.001, slope 3.80 score units per %) or 50 microM H2O2 (p < 0.001, slope 3.22 score units per %). These regression analyses revealed a 2.9-fold greater rate of basal DNA damage in lymphocytes compared to monocytes and an 11.3-fold greater rate for the damage induced by 10 microM H2O2. We conclude that there are marked differences in the rate of basal and induced SSB between lymphocytes and monocytes, suggesting differences in antioxidant capacity between the two cell populations. These findings indicate that the assessment of SSB for biomonitoring and genotoxicity testing using PML has to take into account possible changes in cellular composition.

Adult↗
PubMed1995

Determination of low level exposure to volatile aromatic hydrocarbons and genotoxic effects in workers at a styrene plant.

OBJECTIVES: Low exposures to volatile aromatic hydrocarbons and cytogenetic effects in peripheral white blood cells were determined in 25 healthy workers employed in different areas of a styrene production plant in the former German Democratic Republic. The results were compared with 25 healthy unexposed controls (matched for age and sex) employed in the same company. METHODS: The concentrations of aromatic hydrocarbons determined from active air sampling in all areas of the factory (styrene: 73-3540 micrograms/m3 (< 0.01-0.83 ppm); ethylbenzene 365-2340 micrograms/m3 (0.08-0.53 ppm); benzene 73-3540 micrograms/m3 ( < 0.02-1.11 ppm); toluene 54-2960 micrograms/m3 (0.01-0.78 ppm); xylenes 12-94 micrograms/m3 ( < 0.01-0.02 ppm)) were considerably lower than in the pump house ( > 4000 micrograms/m3 styrene, ethylbenzene, benzene, and toluene; > 500 micrograms/m3 xylenes), which was only intermittently occupied for short periods. Passive personal monitoring, biomonitoring of exhaled air and metabolites (mandelic, phenylglyoxylic, trans, trans-muconic, hippuric, o-, m- and p-methylhippuric acids, and phenol) in urine samples collected before and after an eight hour working shift was used to assess individual exposure. Questionnaires and examination of company records showed that the historical exposure was far higher than that measured. Genotoxic monitoring was performed by nuclease P1-enhanced 32P-postlabelling of DNA adducts in peripheral blood monocytes, and DNA single strand breaks, sister chromatid exchange, and micronuclei in lymphocytes. The content of kinetochores in the micronuclei was determined by immunofluorescence with specific antibodies from the serum of CREST patients. RESULTS: No genotoxic effects related to exposure were detected by DNA adducts or DNA single strand breaks and sister chromatid exchange. The only effect related to exposure was an increase in kinetochore positive micronuclei in peripheral lymphocytes; the frequency of total micronuclei in peripheral lymphocytes did not change. Smoking was confirmed by measurement of plasma cotinine, and no confounding effect was found on any of the cytogenetic variables. CONCLUSIONS: Low occupational exposure to styrene, benzene, and ethylbenzene did not induce alterations of genotoxicological variables except kinetochore positive micronuclei. This is the first reported use of the CREST technique for an in vivo study in occupational toxicology, which thus could serve as a valuable and sensitive technique for toxicogenic monitoring.

Adult↗
PubMed1995

[Effects of the oxidizing agents ozone and nitrogen dioxide on the lung: studies of a cell culture model].

In experimental exposure studies with ozone or nitrogen dioxide a change in lung function and unspecific airway sensitivity was observed. These effects were paralleled by an induction of cellular and biochemical changes. The exposure of isolated cells in vitro led to a decrease in vitality, an increase in permeability and the secretion of mediators very similar to the composition found in bronchoalveolar lavage after in vivo exposure. The cell culture model, therefore, allows the study of the mechanism of these oxidative air pollutants and allows further the understanding of the influence of different cell types on the observed effects in vivo.

Cell Survival↗
PubMed1994

Determination of DNA single-strand breaks in lymphocytes of smokers and nonsmokers exposed to environmental tobacco smoke using the nick translation assay.

The detection of DNA single-strand breaks (SSB) in human mononucleated white blood cells (MWBC) using a modified version of the nick translation assay is presented. This assay allows rapid and sensitive examination of SSB using only 5 ml heparinized blood for an eightfold determination. The assay was standardized by incubation of MBWC in vitro with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a known genotoxic agent. In vitro incubation of MWBC with MNNG induced a dose-dependent increase in DNA-SSB at doses between 5 and 500 microM MNNG. The detection limit for the assay was 5 microM MNNG. To assess the suitability of this assay to detect SSB in vivo a controlled study was performed in which volunteer smokers (n = 5), nonsmokers (n = 5) exposed to environmental tobacco smoke (ETS), and nonsmokers controls (n = 5) were compared. The study lasted 4 experimental days, 2 control and 2 exposure days. On control days (days 1 and 3) smokers and nonsmokers sat in an unventilated 45 m3 room for 8 h. On the exposure days (days 2 and 4) each of the five smokers smoked 24 cigarettes in 8 h, while the five nonsmokers were exposed to the ETS generated by the smoking volunteers. High exposure to tobacco smoke was confirmed by dosimetry of carboxyhemoglobin (CO-Hb), plasma nicotine and cotinine levels. Blood was drawn before and after each exposure on all 4 experimental days for determination of DNA-SSB in lymphocytes immediately after isolation of blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

A novel technique for the detection of DNA single-strand breaks in human white blood cells and its combination with the unscheduled DNA synthesis assay.

A modified assay for the detection of DNA single-strand breaks (SSBs) in human mononucleated white blood cells (MWBCs) based on the nick translation (NT) reaction was developed and combined with the test for unscheduled DNA synthesis (UDS). Both assays were performed on disposable 96-well filtration plates and therefore allowed rapid and sensitive examination of SSBs and UDS. Only 5-8 ml of heparinized blood is required for an eightfold determination in both assays. The uptake of radioactive nucleotide precursors was demonstrated to depend linearly upon the NT reaction time and in both assay systems on the number of investigated cells. The best results and the lowest signal to noise ratio were obtained when the NT assay was performed at 25 degrees C for 20 min. The test was standardized for 150,000 MWBCs/well and a polymerase I concentration of 20 U/ml. The same number of cells were used to measure UDS during a 4-h incubation at 37 degrees C. We observed a dose-dependent increase in SSBs after in vitro incubation with N-methyl-N-nitrosoguanidine (MNNG), with a detection limit of 50 microM when MNNG was present for 1 h and of 5 microM after 20-h incubation period. UDS in MWBCs was increased after treatment for 1 h with MNNG (200 microM) only if poly(ADP)ribose synthesis was inhibited by 3-aminobenzamide. UDS was induced by 320 microM methyl methanesulfonate, but SSBs could only be detected after inhibition of UDS by 100 microM hydroxyurea.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Aberrations↗
PubMed1993

Detection of DNA single-strand breaks in lymphocytes of smokers.

In a controlled study, ten male volunteers (five smokers and five nonsmokers) were subjected to different smoking conditions and compared to five nonsmokers, not exposed to cigarette smoke. During the 4 days of the study, nonsmoking periods were strictly controlled. On the first day the ten subjects were sham exposed. On the second day the five smokers smoked 24 cigarettes in 8 h, while the five nonsmokers were exposed to the environmental tobacco smoke. After another day of sham exposure the smoke exposure was repeated under the same conditions. Blood was drawn before and after exposure and DNA single-strand breaks (SSBs) were analyzed in lymphocytes immediately (1 h) after isolation of cells and after 4 h incubation at 37 degrees C, using a modified assay based on the nick translation reaction. Base levels of unscheduled DNA synthesis (UDS) and UDS levels were determined after 1 h incubation with methyl methanesulfonate. Duplicate analysis using the same method was performed in a second laboratory after transportation of blood samples at 0 degree C on a train from Munich to Hamburg. Tobacco smoke exposure of the subjects increased COHb and plasma cotinine levels. SSBs could be detected in all probands with some interindividual day-to-day and morning-to-evening variations. In four of five active smokers, SSB increases were found after smoking. In nonsmokers exposed to tobacco smoke no exposure-related variation in SSB levels could be detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Differences in DNA adduct formation between monocytes and lymphocytes after in vivo incubation with benzo[a]pyrene.

It was the aim of this study to compare the formation of DNA adducts in different human white blood cells. Lymphocytes and monocytes were isolated from peripheral blood by density centrifugation and by a monocyte-specific antibody linked to magnetic beads. DNA adducts were determined by 32P-postlabelling. After in vitro incubation with benzo[a]-pyrene (B[a]P) we found DNA adducts in monocytes, but not in unstimulated blood lymphocytes. Only after growth stimulation by phytohaemagglutinin did lymphocytes show an adduct pattern similar to monocytes. In contrast, B[a]P-7,8-dihydro-9,10-diolepoxide, an activated intermediate of B[a]P metabolism leads to similar DNA adducts in both cell types. When lymphocytes were incubated in the presence of B[a]P together with monocytes, then after subsequent separation lymphocytes exhibited most of the adducts found in monocytes, though to a lower extent. Our results suggest that unstimulated blood lymphocytes--which are unable to activate metabolically promutagens like B[a]P--receive the genotoxic material to form DNA adducts from other blood cells or from cells in the vessel lining. We conclude that the amount and the pattern of DNA adducts formed in whole white blood cells may be influenced considerably by a variable proportion of monocytes.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1990

32P-postlabelling analysis of DNA adducts in monocytes of smokers and passive smokers.

In a controlled study, ten male volunteers were subjected to different smoking and passive smoking conditions. After 60 h of strictly controlled nonsmoking, five smokers were exposed to mainstream smoke only, while five nonsmokers were exposed to the gas phase of environmental tobacco smoke (ETS). In a second experiment smokers were mainstream and ETS exposed, while nonsmokers were exposed to complete ETS. Blood was drawn before and after smoking and DNA adducts were analysed from blood monocytes by the 32P-postlabelling assay, using the nuclease P1 enhancement method. We detected DNA adducts in monocytes of all probands. These adducts unrelated to smoking showed interindividual differences but only minor intraindividual changes in four samples of the same donor. After smoking interindividually variable additional adducts were visible in active smokers only. These smoking-related adducts had disappeared after 40 h of nonsmoking and reappeared again in three out of five smokers after the second smoking period. We conclude that smoking causes an interindividually variable pattern of DNA adducts in active smokers. These adducts disappear in less than 2 d, owing to the fast turnover of monocytes in the intravascular system. The effects described could not be observed in heavily exposed passive smokers.

Adult↗
PubMedDate not supplied

Determinants of a genotoxic effect of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in human diploid fibroblasts.

The induction of micronuclei was studied in human diploid fibroblasts incubated in the presence of the tobacco-specific nitrosamine NNK. We used four fibroblast strains having a high capacity of O6-alkylguanine DNA alkyltransferase (13.0-23.3 pmol O6-methylguanine repaired per 8 x 10(6) cells) and four strains that showed no detectable repair capacity. Incubation with NNK doubled the frequency of micronuclei in repair-deficient cells but failed to evoke any effect in the proficient cell strains. Control experiments were performed with the direct methylating agent MNNG and in the presence of inhibitors of either metabolic activation or alkyltransferase. The results showed that the genotoxicity of NNK is dependent on the relationship between its metabolic activation and the constitutive DNA repair. This supports earlier findings that low constitutive levels of O6-alkylguanine DNA alkyltransferase may increase susceptibility to lung cancer after exposure to DNA methylating agents.

Adult↗