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O Holz

Publications and source records attributed to O Holz.

At least 19 recordsLinked to original sources
PubMed2002

The relationship between airway hyper-responsiveness, markers of inflammation and lung function depends on the duration of the asthmatic disease.

BACKGROUND: The combination of airway hyper-responsiveness, eosinophilic airway inflammation, and lung function impairment is considered as a hallmark of bronchial asthma. Since airway function might change with time in chronic asthma, the association between parameters which are characteristic of asthma could be different in subjects with different durations of the disease. OBJECTIVE: We assessed whether in patients with asthma the relationship between airway hyperresponsiveness, non-invasive markers of airway inflammation, and baseline lung function depended on the duration of the disease. METHODS: Sixty-six non-smoking patients with mild to moderate allergic asthma without corticosteroids were assigned to two groups, according to a duration of the disease (time interval since doctor's diagnosis) of either < or = 16 years (median 8 years; mean FEV1, 92.6% pred.; n = 34) or > 16 year (median 25 years; mean FEV1, 87.9% pred.; n = 32). RESULTS: Groups did not differ statistically in PC20FEV1 of methacholine, sputum composition, levels of exhaled nitric oxide (NO), lung function parameters, or history of treatment. There were significant correlations between PC20FEV1, eosinophils and NO in patients with a duration of the disease < or = 16 year, but no relation to lung function. In contrast, patients with a duration > 16 year showed a correlation between PC20FEV1 of methacholine and lung function but not eosinophils or NO. In both groups, eosinophils and NO were associated with each other. These results were corroborated by the statistical procedure of factor analysis that revealed 'inflammation' and 'lung function' as major entities and found 'responsiveness' to be associated with only one of them in each group. CONCLUSION: Our data demonstrate that with a shorter duration of the asthmatic disease airway hyper-responsiveness is associated with airway inflammation, whereas with a longer duration it is associated with impaired lung function, suggesting that in chronic asthma ongoing alterations become the primary determinant of functional characteristics.

Adult↗
PubMed2002

Repeated ozone exposures enhance bronchial allergen responses in subjects with rhinitis or asthma.

BACKGROUND: Single exposures to > 200 p.p.b. of ozone are capable of enhancing the early-phase lung function response to allergen. OBJECTIVE: The aim of the present study was to compare the effect of single vs. repeated exposures to ozone on early and late-phase allergen responses. METHODS: Eleven subjects with allergic asthma and 22 subjects with allergic rhinitis underwent single exposures to filtered air, 125 p.p.b. and 250 p.p.b. ozone, as well as repeated exposures to 125 p.p.b. ozone on four consecutive days. Twenty hours after the (final) exposure, subjects inhaled a single dose of allergen and a sputum induction was performed 6-7 h later. RESULTS: In the subjects with rhinitis, the mean early-phase response of FEV1 and the number of > or = 20% reductions were significantly greater after exposure to 250 or 4 x 125 p.p.b. ozone compared with filtered air. In addition, most of the > or = 15% late-phase responses in FEV1 occurred after exposure to 4 x 125 p.p.b., as well as the strongest effects on sputum parameters. The rise in the number of eosinophils was statistically significant in both groups. Regarding the number of lymphocytes and the concentrations of mast cell tryptase, histamine or LDH, significance was, however, only reached in the asthma group. CONCLUSION: Our data suggest that repeated exposure to ozone, at a peak ambient air level, can enhance both functional and inflammatory responses to inhaled allergen in subjects with pre-existing allergic airway diseases, and that these effects might reach a clinically relevant magnitude.

Adult↗
PubMed2002

Sputum induction.

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Administration, Inhalation↗
PubMed2001

Airway response to inhaled hypertonic saline in patients with moderate to severe chronic obstructive pulmonary disease.

The present study aimed at delineating the mechanisms underlying the adverse response to hypertonic saline inhalation in patients with chronic obstructive pulmonary disease (COPD). Twenty patients (age, 48-70 yr; FEV(1), 29-58 %pred) inhaled, on two different days in randomized order, 200 microg salbutamol from an MDI and 20 min later either 0.9% or 3% saline from an ultrasonic nebulizer for a maximum of four consecutive 5-min periods. Forced expiratory (FEV(1)) and inspiratory (FIV(1)) volumes, inspiratory capacity (IC), intrathoracic gas volume (ITGV), and specific airway resistance (SRaw) were measured. Significant changes occurred in FEV(1), FIV(1), IC, ITGV, and SRaw with both concentrations (p < 0.05, each) and effects were stronger with 3% as compared with 0.9% saline (p < 0.05, each). The increase in dyspnea was associated with the changes in FIV(1), FEV(1), IC, and ITGV, in contrast to its decrease during bronchodilation, where only FIV(1) was important. Sputum analysis showed elevated concentrations of histamine after 3% as compared with 0.9% saline. These data indicate that the adverse lung function response to hypertonic saline is common in patients with moderate to severe COPD, involves both bronchoconstriction and lung hyperinflation, and could be mediated, at least partially, through activation of mast cells.

Administration, Inhalation↗
PubMed2001

Flow cytometric analysis of lymphocyte subpopulations in bronchoalveolar lavage fluid after repeated ozone exposure.

As known from studies in animal and human subjects, ozone can exert effects on the immune response including allergic sensitisation and allergen responsiveness. The objective of the present study was to assess the changes in lymphocyte subsets in bronchoalveolar lavage fluid (BALF) after single and repeated ozone exposures. Twenty-three healthy subjects underwent single exposures to 200 ppb ozone or filtered air (FA), as well as repeated exposures to 200 ppb ozone on four consecutive days, each during 4 h of intermittent exercise. Bronchoalveolar lavage was performed 20 h after the single exposure or the last of the repeated exposures. Lymphocytes were identified by sideward scatter and CD45 expression, and their subsets by eight different panels of antibodies. Checksums were calculated to assess the validity of the results. The percentage and the absolute number of lymphocytes, mostly comprising T-lymphocytes (CD2+; overall mean 98.8%), increased after single (P < 0.05; each), but not after repeated ozone exposure, compared with FA (7.4 vs 5.8 vs 6.5%; 680 vs 419 vs 301 x 10(3)). In addition, we observed small but statistically significant changes in the proportions of lymphocyte subpopulations. The percentage of CD4+ lymphocytes increased after single (P < 0.05) and repeated ozone exposure (P < 0.01), whereas the percentage of CD8+ cells decreased after repeated exposure (P < 0.05). The proportion of activated lymphocytes (CD25+) was elevated after repeated, compared with single, ozone exposure (P < 0.01), and the percentages of natural killer (NK) cells were decreased after both single (P < 0.05) and repeated (P < 0.01) exposures. Our data suggest that single but not repeated ozone exposures cause a change in absolute numbers of lymphocytes in BALF, whereas the proportions of lymphocyte subsets are affected by single as well as repeated exposures.

Adult↗
PubMed2001

Freezing of homogenized sputum samples for intermittent storage.

BACKGROUND: Among the reasons that restrict the application of sputum induction in outpatient settings is the need for processing of samples within 2 h after induction. OBJECTIVE: The aim of our study was to assess whether freezing is suitable for intermediate storage of sputum samples before processing. METHODS: We compared differential cell counts between two sputum aliquots derived from the same sample. One aliquot was processed within 2 h after production and one, after it had been frozen under addition of dimethyl-sulfoxid (DMSO) and stored up to 10 days at -20 degrees C. Thirty-five samples were frozen immediately prior to preparation of cytospins, and 10 samples were frozen at an even earlier stage, directly after homogenization. RESULTS: In both sets of experiments we observed a significant relationship between frozen and native samples regarding macrophages, neutrophils and eosinophils, as indicated by respective intraclass correlation coefficients of 0.96, 0.96, and 0.93 in the first, and of 0.92, 0.96 and 0.77 in the second experiments. CONCLUSION: Our results indicate that the freezing of sputum samples at different stages of processing does not alter sputum morphology to an extent that affects the results of differential cell counts.

Adult↗
PubMed2000

Update on sputum methodology.

Over the past few years cellular and biochemical sputum examinations have become important instruments to assess airway inflammation. The aim of this review is to summarize new methodological developments and aspects, which are currently under investigation. The use of isotonic saline has increased safety of inductions in patients with severe asthma and in children. The origin of sputum is better understood, as is the need to standardize the volume and duration of induction. It also needs to be borne in mind that the induction procedure itself is able to cause changes in sputum composition. However, the basic induction and processing procedures have not changed much over the last few years, and therefore the method is still time consuming. The analysis of ECP in lysed sputum cells as a marker for the number of eosinophils has been suggested to overcome this problem, but needs further validation. Furthermore, storage of sputum has been studied, as well as early fixation or freezing of sputum cells to elongate the time between induction and processing. Differential cell counts by flow cytometry are still difficult, but the method has increased knowledge concerning lymphocyte subsets and the activation status of sputum cells. The use of induced sputum to noninvasively measure airway inflammation in clinical trials will offer additional information, but the proper use and interpretation of sputum outcome parameters will need further investigation.

Administration, Inhalation↗
PubMed2000

The concentration of hydrogen peroxide in exhaled air depends on expiratory flow rate.

Hydrogen peroxide (H2O2) is known to be detectable in exhaled air. The present study aimed to determine whether the concentration of exhaled H2O2 depends on expiratory flow rate in order to make inferences on the site of its production within the lung. Breath condensate was collected in cooled Teflon tubes, at three different expiratorv flow rates, in 15 healthy or mild asthmatic subjects. Tests were repeated 2-5 times to assess reproducibility. Mean+/-SEM concentrations of H2O2 at flow rates of 140, 69 and 48 mL.s(-1) were 0.12+/-0.02, 0.19+/-0.02 and 0.32+/-0.03 microM, respectively. These values differed significantly from each other (p<0.001). For comparison, average coefficients of variability within repeated measurements at each of the three flow rates were 68, 62 and 82%, respectively. These data demonstrate that the concentration of exhaled hydrogen peroxide depends on expiratory flow rate. Since flow dependence is an indicator of production within the airways, this result suggests that, to a large extent, the exhaled hydrogen peroxide originates within the airways. However, even under strictly controlled conditions, a high degree of variability persists, which may limit the usefulness of exhaled hydrogen peroxide as a marker of airway inflammation.

Adult↗
PubMed2000

Noninvasive methods to measure airway inflammation: future considerations.

This last contribution to the series focuses on open questions regarding: 1) methodological issues; and 2) the potential clinical application of the noninvasive methods such as induced sputum and the analysis of exhaled air for the assessment of airway inflammation. In addition their potential future role in occupational health and the early diagnosis of neoplastic lesions are briefly discussed. The future clinical application of noninvasive methods will depend on the progress made to improve their practicability, particularly in rendering them less time consuming and cheaper. To assess their clinical value, prospective studies are needed to establish whether patients actually benefit from the results obtained. This is also important to implement the methods into the healthcare system and to obtain adequate financial compensation. Therefore, it is necessary to know: 1) whether the assessment of airwav inflammation can aid in coming to an earlier and better defined diagnosis; 2) whether by repeated monitoring it is possible to avoid exacerbations through earlier interventions; and 3) whether the long-term outcome of patients is improved through knowledge of the type and degree of airway inflammation that is taken into account in selecting the appropriate treatment. In the meantime a wealth of data has become available, both for induced sputum and the analysis of exhaled air, which give these methods the potential to be incorporated into future clinical practice. This, however, will, amongst the other issues, depend on favourable cost-benefit ratios which should also be the subject of future prospective studies.

Breath Tests↗
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↗