Heart rate variability, hemostatic and acute inflammatory blood parameters in healthy adults after short-term exposure to welding fume

The present study aimed to investigate, whether short-term experimental exposure to high levels of welding fumes would be capable of exerting acute effects in healthy subjects. Specifically, we assessed cardiovascular function in terms of heart rate variability (HRV) as well as the concentrations of inflammatory mediators and hemostatic proteins in blood as outcome measures. Twenty subjects without a history of airway and cardiovascular diseases were exposed to either control air or welding fume for 1 h on 2 separate days under standardized conditions. The median concentration of the alveolar particle fraction during welding was 3.5 mg/m(3 )(quartiles: 1.4-6.3 mg/m(3); range 1.0-25.3 mg/m(3)). Five hours later a panel of clinical assessments was performed, including HRV measurement and drawing of blood samples. There were no changes in symptom ratings or lung function after welding fume exposure. Exposures did also not differ regarding effects on time- and frequency-domain parameters of HRV. Similarly, blood leukocyte numbers, cell differentials and the blood levels of fibrinogen, C-reactive protein, antithrombin III, factor VIII, von Willebrand factor, ristocetin cofactor, sICAM-1, tumor necrosis factor alpha, interleukin 6, interleukin 8 and epithelial neutrophil activating peptide 78 were not altered by welding fume inhalation. However, there was a significant fall in the level of endothelin-1 (P < 0.01). In conclusion, the data did not indicate effects of clinical significance of a short-term high-level exposure to welding fumes on HRV or a set of blood hemostatic and acute inflammatory parameters in healthy subjects. The small but statistically significant effect on endothelin levels demonstrated that measurable effects could be elicited even in these individuals. Overall, welding fumes are not likely to exert acute cardiovascular effects in healthy individuals.

Time course of exhaled hydrogen peroxide and nitric oxide during chemotherapy

This study was designed to assess the effect of differential leukocyte depletion during chemotherapy by monitoring the levels of exhaled hydrogen peroxide H2O2 and nitric oxide (F(eNO)) present. In 39 patients with lung cancer (chronic obstructive pulmonary disorder up to stage II, median forced expiratory volume in one second 78% predicted), measurements were performed before a cycle of therapy (day 1), at least once during the cycle (day 8: n = 34; day 15: n = 19), and afterwards (days 21-29). There were significant changes in the level of H2O2, F(eNO) and peripheral blood cell differentials over the visits. The level of H2O2 was decreased only on day 15, with a median (difference between the upper and lower quartiles) fall of 31 (57)%, while F(eNO) was reduced only on day 8, by 22 (40)%. Neutrophil numbers were unchanged on day 8 and decreased by 59 (48)% on day 15, while monocyte numbers were decreased on day 8 by 87 (39)%. On days 21-29, values had returned to baseline. Taken together with previous findings, the parallel course of levels of exhaled hydrogen peroxide and neutrophil counts suggests that a major part of exhaled hydrogen peroxide is due to neutrophils via the conducting airways. In contrast, the production of exhaled nitric oxide seems to be primarily associated with monocytes.

Lung fibroblasts from patients with emphysema show markers of senescence in vitro

BACKGROUND

The loss of alveolar walls is a hallmark of emphysema. As fibroblasts play an important role in the maintenance of alveolar structure, a change in fibroblast phenotype could be involved in the pathogenesis of this disease. In a previous study we found a reduced in vitro proliferation rate and number of population doublings of parenchymal lung fibroblasts from patients with emphysema and we hypothesized that these findings could be related to a premature cellular aging of these cells. In this study, we therefore compared cellular senescence markers and expression of respective genes between lung fibroblasts from patients with emphysema and control patients without COPD.

METHODS

Primary lung fibroblasts were obtained from 13 patients with moderate to severe lung emphysema (E) and 15 controls (C) undergoing surgery for lung tumor resection or volume reduction (n = 2). Fibroblasts (8E/9C) were stained for senescence-associated beta-galactosidase (SA-beta-Gal). In independent cultures, DNA from lung fibroblasts (7E/8C) was assessed for mean telomere length. Two exploratory 12 k cDNA microarrays were used to assess gene expression in pooled fibroblasts (3E/3C). Subsequently, expression of selected genes was evaluated by quantitative PCR (qPCR) in fibroblasts of individual patients (10E/9C) and protein concentration was analyzed in the cell culture supernatant.

RESULTS

The median (quartiles) percentage of fibroblasts positive for SA-beta-Gal was 4.4 (3.2;4.7) % in controls and 16.0 (10.0;24.8) % in emphysema (p = 0.001), while telomere length was not different. Among the candidates for differentially expressed genes in the array (factor > or = 3), 15 were upregulated and 121 downregulated in emphysema. qPCR confirmed the upregulation of insulin-like growth factor-binding protein (IGFBP)-3 and IGFBP-rP1 (p = 0.029, p = 0.0002), while expression of IGFBP-5, -rP2 (CTGF), -rP4 (Cyr61), FOSL1, LOXL2, OAZ1 and CDK4 was not different between groups. In line with the gene expression we found increased cell culture supernatant concentrations of IGFBP-3 (p = 0.006) in emphysema.

CONCLUSION

These data support the hypothesis that premature aging of lung fibroblasts occurs in emphysema, via a telomere-independent mechanism. The upregulation of the senescence-associated IGFBP-3 and -rP1 in emphysema suggests that inhibition of the action of insulin and insulin-like growth factors could be involved in the reduced in vitro-proliferation rate.

[Possibilities and perspectives of home-based exercise training in patients with chronic obstructive pulmonary diseases]

In Germany there is a long tradition of rehabilitation and exercise training programs to improve the clinical state and physical function of patients with chronic obstructive pulmonary diseases. This is particularly true regarding inpatient rehabilitation. Based on experiences gained in other countries, outpatient and home-based programs are currently getting more attention. One of the key components of pulmonary rehabilitation is exercise training which can be expected to exert direct and indirect beneficial effects on physical performance, health-related quality of life and even the progress of the disease. Most of the available experience refers to patients with COPD -- besides those with bronchial asthma. The data available so far suggest that exercise training programs can reduce exacerbation rates and that this effect is achievable by minimal personal assistance. Thus the most important aim of future studies seems to be the development and evaluation of training programs which are efficient but also easy to implement and minimally expensive. Furthermore it needs to be studied whether such programs can be transferred to pulmonary disorders other than obstructive airway diseases.

Predictive value of BAL cell differentials in the diagnosis of interstitial lung diseases

The current authors aimed to quantify how the likelihood for a given diagnosis changes with the knowledge of bronchoalveolar lavage (BAL) cell differentials. As an initial estimate (a priori probability), frequencies of final diagnoses were taken. Using categorisations for cell differentials, a posteriori probabilities were then derived for each disease, according to Bayes. The analysis was performed in three of five groups of diagnoses suspected prior to BAL: interstitial lung disease (ILD; n=710), inflammatory disease (n=583), or lung tumour mimicking ILD (n=455). Overall, out of 1,971 patients, 18.3% had sarcoidosis, 7.7% usual interstitial pneumonia (UIP), 4.4% extrinsic allergic alveolitis (EAA), and 19.0% tumours. In the group with suspected ILD, the likelihood for sarcoidosis increased from 33.7 to 68.1% when lymphocyte numbers were 30-50% and granulocyte numbers were low; the likelihood for UIP increased from 15.8 to 33.3% when lymphocyte numbers were <30% with granulocytes elevated. CD4/CD8 was informative, especially in sarcoidosis and EAA. Despite considerable increases, the likelihood of rare diseases rarely reached appreciable values. Similar results were obtained in the other two groups of suspected diagnoses. In conclusion, these data suggest that bronchoalveolar lavage cell counts per se provide substantial diagnostic information only in relatively frequent diseases, such as sarcoidosis and usual interstitial pneumonia, and are less helpful in infrequent diseases.

Effect of freezing of sputum samples on flow cytometric analysis of lymphocyte subsets

Sputum samples should be processed shortly after induction to prevent cell degradation. For intermediate storage, freezing of homogenised samples or immediate fixation have been shown to be suitable for cytospins. The aim of this study was to investigate whether freezing or immediate fixation of sputum affect the analysis of lymphocyte subsets by flow cytometry. Selected plugs from 24 sputum samples were homogenised. One aliquot was processed immediately and analysed by flow cytometry. A second aliquot was homogenised, frozen at -20 C after addition of dimethylsulfoxide and stored for a median time of 6 days. In six samples a third aliquot was fixed in formalin after induction and stored for up to 72 h before further processing. Compared to immediate processing, percentages of total lymphocytes and T-suppressor cells were elevated after being frozen, with a minor decrease in the T4/T8 ratio. Proportions of total lymphocytes, T-helper and T-suppressor cells correlated between native and frozen samples, intra-class correlation coefficients being 0.74, 0.85 and 0.70, respectively. The formalin-fixed aliquots could not be analysed with the antibodies used. In conclusion, freezing seems to be a suitable technique to store sputum samples for flow cytometry of CD3, CD4 and CD8 lymphocyte subsets. Its effects were minor compared to the variation between subjects.

Comparison of exhaled nitric oxide analysers

Currently no published data are available concerning the comparability of different types of NO analysers, making inter-laboratory comparisons difficult. In two sets of experiments we compared 4 and 5 NO analysers, respectively, from 3 different manufacturers using different calibration regimes: calibration with (1) a separate recommended calibration gas for each analyser, (2) a single low concentration for all (394 ppb), and (3) a single high concentration (12.8 ppm). We measured three subjects with known low (L), moderate (M) and high (H) bronchial exhaled nitric oxide concentrations as well as standard gases (SG). In the first set of experiments, calibration regime 1 resulted in the largest differences between analysers (coefficient of variation (CV) for L, M, H, SG: 0.42, 0.22, 0.20, 0.14). The lowest CV between analysers was observed after calibration 2 (0.34, 0.19, 0.12, 0.02). Very similar results were obtained in the second set of comparisons. Thus, differences between analysers existed, but were mainly due to differences in recommended calibration gases/procedures. Only a small part was explainable by deviations from target flow. These differences need to be taken into account when comparing data between laboratories or replacing the calibration gas of an analyser, as well as for the establishment and interpretation of normal values.

Lung fibroblasts from patients with emphysema show a reduced proliferation rate in culture

Emphysema is characterised by a loss of alveolar structure, as reflected in elastic recoil and gas exchange. As fibroblasts play a key role in the maintenance of structure, the current authors hypothesised that their proliferation might be constitutively impaired in lung emphysema. Using explant cultures, lung fibroblasts were obtained from resected lungs of 10 patients with emphysema (median forced expiratory volume in one second (FEV1) 40% predicted) and 10 control patients (FEV1, 95% pred). The doubling time (DT) was measured over 4 days under standard conditions (10% foetal calf serum) prior and after cryopreservation. Additionally, in seven samples per group the total population doubling level (PDL) was determined. In emphysema, mean+/-sem DT was 33.6+/-2.8 h compared with 24.8+/-1.4 h in controls. The differences in DT were preserved after cryopreservation. Groups also differed in the initial slope of the PDL plot during long-term culture (up to 35 days). However, the median (range) maximum PDL did not differ significantly between groups (13.8 (7.4-22.6) versus 20.2 (11.2-25.5)). The current authors, therefore, suggest that the reduced proliferation rate in vitro of lung fibroblasts from patients with emphysema reflects a persistent, intrinsic failure of cellular replacement and maintenance in this disease, possibly in relation to pre-term aging.

[Non-invasive methods for monitoring airway inflammation: a comparison of expenditures, gain and clinical value]

Among the noninvasive procedures for the assessment of airway inflammation, the analysis of spontaneous sputum is currently the only method, the expenses of which are covered by health insurance in Germany. It can easily be used for semiquantitive cytological analyses by practising pneumologists. Recent data also indicate the usefulness of sputum induction, particularly in asthma diagnosis and therapy control, and demonstrate its capability of reducing total costs per patient. In contrast to sputum analysis, the measurement of exhaled nitric oxide (NO) yields a read-out without time delay. NO as associated with eosinophils also seems suitable for monitoring airway inflammation. The number of studies regarding NO, both its pathophysiological role and clinical use, is far greater than that regarding any other marker of exhaled air. Measurements are easy and fast, but the costs of analysers are still prohibitive in clinical practice. The analysis of other compounds of exhaled air, particularly those of exhaled breath condensate (EBC), offers fascinating perspectives, owing to the scope of markers that might be measured, and could enable the assessment of multivariate profiles that are useful for diagnosis and therapy control. Currently, however, the method still faces methodological questions, and data indicating its usefulness and cost-efficiency in clinical practice are scarce. Compared to NO, the expenses per measurement in clinical use are mainly due to the costs per marker detection after sampling, as well as storage and transport of samples. The on-site analysis of pH in the EBC could be a first step to circumvent this obstacle.