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Bochum-Hordel, Germany

Nensa F.,Ruhr University Bochum | Kotschy-Lang N.,Berufsgenossenschaftliche Klinik fur Berufskrankheiten | Smith H.-J.,34 GmbH | Marek W.,Institute of Occupational Physiology | Merget R.,Ruhr University Bochum
Advances in Experimental Medicine and Biology | Year: 2013

While methacholine (MCH) testing is commonly used in the clinical diagnosis of asthma, the detection of airway narrowing often relies on either spirometry or body plethysmography, however comparative studies are rare. In this study we performed MCH testing in 37 patients with variable shortness of breath at work and in 37 patients with no history of airway disease. The inclusion criteria were: no acute respiratory infection within 6 weeks, no severe diseases, normal baseline specific airway resistance (sRaw), normal baseline forced expiratory volume in 1 s (FEV1), Tiffeneau index >70%, no previous treatment with steroids within 14 days and no short acting bronchodilators within 24 h. Cumulative doses of 0.003, 0.014, 0.059, 0.239 and 0.959 mg MCH were inhaled by a dosimeter method. A FEV1 decrease of ≥20% from baseline and a 100% increase of sRaw to ≥2.0 kPa/s was defined as end-of-test-criterion. Provocation doses were calculated by interpolation. Performance of lung function parameters was compared using receiver-operating- characteristic (ROC) analysis. ROC analysis resulted in an area under the ROC curve (AUC) of 0.74 for FEV1 vs. 0.82 for sRaw. The corresponding Youden Indices (J) were 0.46 for FEV1 and 0.57 for sRaw. The Youden Index of sRaw was higher and sensitivity and specificity (73%/84%) were rather well-balanced, in contrast to FEV 1 (54%/92%). In conclusion, in cumulative MCH challenges sR aw was found to be the overall most useful parameter for the detection of bronchial hyperresponsiveness. Body plethysmography yielded a balanced sensitivity-specificity ratio with higher sensitivity than spirometry, but comparable specificity. © Springer Science+Business Media Dordrecht 2013. Source

Marek E.M.,Ruhr University Bochum | Volke J.,Ruhr University Bochum | Hawener I.,Ruhr University Bochum | Platen P.,Ruhr University Bochum | And 2 more authors.
Journal of Breath Research | Year: 2010

Arterial lactate concentrations, taken as indicators of physical fitness, in athletes as well as in patients with cardio-respiratory or metabolic diseases, are measured invasively from arterialized ear lobe blood. Currently developed micro enzyme detectors permit a non-invasive measurement of hypoxia-related metabolites such as lactate in exhaled breath condensate (EBC). The aim of our study is to prove whether this technology will replace the traditional measurement of lactate in arterialized blood. Therefore, we determined the functional relation between lactate release in EBC and lactate concentration in blood in young and healthy subjects at rest and after exhausting bicycle exercise. During resting conditions as well as after exhausting bicycle exercise, 100 L of exhaled air along with blood samples from the ear lobe was collected after stationary load conditions in 16 healthy subjects. EBC was obtained by cooling the expired air volume with an ECoScreen I (FILT GmbH, Berlin) condenser. The analysis was performed within 90 min using an ECoCheck ampere meter (FILT GmbH, Berlin). Lactate measurements were performed using a bi-enzyme sensor after lactate oxidase-induced oxidation of lactate to pyruvate and H2O2. The rates of lactate release via the exhaled air were calculated from the lactate concentration, the volume and the collection time of the EBC. The functional relation of lactate release in exhaled air and lactate concentration of arterial blood was computed. At rest, the mean lactate concentration in arterialized blood was 0.93 0.30 mmol L-1. At a resting ventilation of 11.5 3.4 L min-1, the collection time for 100 L of exhaled air, Ts, was 8.4 2.9 min, and 1.68 0.40 mL EBC was obtained. In EBC, the lactate concentration was 21.4 7.7 νmol L -1, and the rate of lactate release rate in collected EBC was 4.5 1.7 nmol min-1. After maximal exercise load (220 20 W), the blood lactate concentration increased to 10.9 1.8 mmol L-1 and the ventilation increased to 111.6 21.4 L min-1. The EBC collection time decreased to 3.9 1.9 min, and 1.20 0.44 mL EBC were obtained in the recovery period after termination of exercise. The lactate concentration in EBC increased to 40.3 23.0 νmol L-1, and the lactate release in EBC increased to 13.6 8.6 nmol min-1 (p < 0.01). Assuming a volume of 4.3 mL water in 100 L of exhaled air (saturated with water at 37 °C), we calculated a lactate release at rest of 11.5 4.3 nmol min-1 and 48.6 30.7 nmol min-1 (p < 0.01) after exhausting exercise. Detectable releases of lactate in exhaled breath condensate were found already under resting conditions. During exhausting external load on a bicycle spiroergometer, an increase in the lactate concentration was found in arterialized blood along with an increased lactate release in EBC. The correlation between expiratory lactate release via EBC and lactate concentration in arterialized blood is studied in pursuing investigations. © 2010 IOP Publishing Ltd. Source

Marek E.,Ruhr University Bochum | Volke J.,Ruhr University Bochum | Smith H.-J.,Carefusion Corporation | Serbetci B.,Institute of Occupational Physiology | And 4 more authors.
Advances in Experimental Medicine and Biology | Year: 2013

The anthropometrical data of the Caucasian population have significantly changed within the last five decades. The European Community for Coal and Steel (ECCS) assumes a plateau phase and recommends the entry of 25 years old for calculation of reference values in this age range. The question arises if the commonly used reference recommendations for lung function of the ECCS can still be accepted. In the present study standardized spirometric lung function tests were performed by pneumotachography, recording lung volumes and flows (MasterScreen Pneumo, CareFusion, Höchberg) in asymptomatic nonsmoking subjects (202 females, 201 males), aged between 18 and 26, according to the ATS/ERS criteria. The results were compared with the reference recommendations of ECCS, SAPALDIA, LuftiBus, and Bochum (only males). All absolute lung function values showed a correlation (p< 0.05) with height. With respect to FVC and FEV1, SAPALDIA and Bochum reference values were comparable and close to a 100 (range 97.6-101.4) %pred, whereas both ECCS and LuftiBus showed higher values (range 103.6-109.9%pred). The FEV1/FVC ratio was close to a 100 (range 97.6-101.7) %pred in all reference systems, whereas flows showed a wide variability between the reference systems (77.1-114.6%pred), single flows (e.g., 96.9-114.2%pred for MEF50) and males/females (males: 93.6-114.6%pred; females: 77.1-107.9%pred). We conclude that SAPALDIA reference values for FVC and FEV1 should be used, as they better represent lung function in the age group. ECCS and LuftiBus reference values are appreciably (4-10%) lower. Differences between reference systems were less important for the FEV1/FVC ratio and lung flows. © Springer Science+Business Media Dordrecht 2013. Source

Marek E.,Ruhr University Bochum | Volke J.,Ruhr University Bochum | Muckenhoff K.,Institute of Occupational Physiology | Platen P.,Ruhr University Bochum | Marek W.,Institute of Occupational Physiology
Advances in Experimental Medicine and Biology | Year: 2013

Athletes have changes in the lung epithelial cells caused by inhalation of cold and dry air. The exhaled breath condensate contains a number of mediators from the respiratory system and H2O2 is described as a marker of airways inflammation. The aim of this study was to determine the influence of exercise combined with cold air on the H2O2 release in the exhaled breath. Twelve males (23.1 ± 1.5 years) were randomly assigned at 2 different days (1 day rest) to perform a 50 min run (75-80% of their max. heart rate) under normal (N) laboratory (18.1 ± 1.1°C) or cold (C) field condition (-15.2 ± 3.1°C). Before and immediately after each run, the EBC was collected under laboratory conditions and was analyzed amperometrically. Prior to the two runs, H2O 2 concentrations were 145.0 ± 31.0 (N) and 160.0 ± 49.1 nmol/L (C) and theoretical release was 70.3 ± 37.1 (N) and 82.6 ± 27.1 pmol/min (C) (p > 0.05). After each run, H2O2 concentration increased significantly to 388.0 ± 22.8 nmol/L (N) and 622.1 ± 44.2 nmol/L (C) (p < 0.05), along with an increase in the theoretical release: 249.2 ± 35.7 pmol/min (N) and 400.9 ± 35.7 pmol/min (C) (p < 0.05). We conclude that release of H2O 2 into the EBC takes place under both resting conditions and after exercise. The concentration and release of H2O2 increased after exercise in cold air compared to resting and laboratory conditions, which points to an increase in inflammatory and oxidative stress. © 2013 Springer Science+Business Media Dordrecht. Source

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