Chronic cough due to occupational factors

Within the large variety of subtypes of chronic cough, either defined by their clinical or pathogenetic causes, occupational chronic cough may be regarded as one of the most preventable forms of the disease. Next to obstructive airway diseases such as asthma or chronic obstructive pulmonary disease, which are sometimes concomitant with chronic cough, this chronic airway disease gains importance in the field of occupational medicine since classic fiber-related occupational airway diseases will decrease in the future. Apart from acute accidents and incidental exposures which may lead to an acute form of cough, there are numerous sources for the development of chronic cough within the workplace. Over the last years, a large number of studies has focused on occupational causes of respiratory diseases and it has emerged that chronic cough is one of the most prevalent work-related airway diseases. Best-known examples of occupations related to the development of cough are coal miners, hard-rock miners, tunnel workers, or concrete manufacturing workers. As chronic cough is often based on a variety of non-occupational factors such as tobacco smoke, a distinct separation into either occupational or personally -evoked can be difficult. However, revealing the occupational contribution to chronic cough and to the symptom cough in general, which is the commonest cause for the consultation of a physician, can significantly lead to a reduction of the socioeconomic burden of the disease

Long-Term Efficacy of Pulmonary Rehabilitation in Patients with Occupational Respiratory Diseases

Background: Pulmonary rehabilitation is a well-recognized treatment option in chronic obstructive lung disease improving exercise performance, respiratory symptoms and quality of life. In occupational respiratory diseases, which can be rather cost-intensive due to the compensation needs, very little information is available. Objectives: This study aims at the evaluation of the usefulness of pulmonary rehabilitation in patients with occupational respiratory diseases, partly involving complex alterations of lung function and of the sustainability of effects. Methods: We studied 263 patients with occupational respiratory diseases (asthma, silicosis, asbestosis, chronic obstructive pulmonary disease) using a 4-week inpatient rehabilitation program and follow-up examinations 3 and 12 months later. The outcomes evaluated were lung function, 6-min walking distance (6MWD), maximum exercise capacity (Wmax), skeletal muscle strength, respiratory symptoms, exacerbations and associated medical consultations, quality of life (SF-36, SGRQ), anxiety/depression (HADS) and Medical Research Council and Baseline and Transition Dyspnea Index scores. Results: Compared to baseline, there were significant (p < 0.05) improvements in 6MWD, Wmax and muscle strength immediately after rehabilitation, and these were maintained over 12 months (p < 0.05). Effects were less pronounced in asbestosis. Overall, a significant reduction in the rate of exacerbations by 35%, antibiotic therapy by 27% and use of health care services by 17% occurred within 12 months after rehabilitation. No changes were seen in the questionnaire outcomes. Conclusions: Pulmonary rehabilitation is effective even in the complex settings of occupational respiratory diseases, providing sustained improvement of functional capacity and reducing health care utilization. Copyright (C) 2012 S. Karger AG, Base

Magnon squeezing in conical spin spirals

We investigate squeezing of magnons in a conical spin spiral configuration. We find that while the energy of magnons propagating along the $\boldsymbol{k}$ and the $-\boldsymbol{k}$ directions can be different due to the non-reciprocal dispersion, these two modes are connected by the squeezing, hence can be described by the same squeezing parameter. The squeezing parameter diverges at the center of the Brillouin zone due to the translational Goldstone mode of the system, but the squeezing also vanishes for certain wave vectors. We discuss possible ways of detecting the squeezing

Chronic cough due to occupational factors

Within the large variety of subtypes of chronic cough, either defined by their clinical or pathogenetic causes, occupational chronic cough may be regarded as one of the most preventable forms of the disease. Next to obstructive airway diseases such as asthma or chronic obstructive pulmonary disease, which are sometimes concomitant with chronic cough, this chronic airway disease gains importance in the field of occupational medicine since classic fiber-related occupational airway diseases will decrease in the future. Apart from acute accidents and incidental exposures which may lead to an acute form of cough, there are numerous sources for the development of chronic cough within the workplace. Over the last years, a large number of studies has focused on occupational causes of respiratory diseases and it has emerged that chronic cough is one of the most prevalent work-related airway diseases. Best-known examples of occupations related to the development of cough are coal miners, hard-rock miners, tunnel workers, or concrete manufacturing workers. As chronic cough is often based on a variety of non-occupational factors such as tobacco smoke, a distinct separation into either occupational or personally -evoked can be difficult. However, revealing the occupational contribution to chronic cough and to the symptom cough in general, which is the commonest cause for the consultation of a physician, can significantly lead to a reduction of the socioeconomic burden of the disease

Independent Information of Nonspecific Biomarkers in Exhaled Breath Condensate

Background: Exhaled breath condensate (EBC) has been used for diagnosing and monitoring respiratory disorders. For clinical purposes the assessment of easy-to-obtain nonspecific markers seems particularly interesting. Objectives: As these measures are related to each other, our objective was to extract the independent information in global EBC markers across a range of respiratory disorders. Methods: EBC was collected from patients with asthma (n = 18), chronic obstructive pulmonary disease (n = 17), and cystic fibrosis (n = 46), as well as from lung transplant (LTX) recipients (n = 14) and healthy controls (n = 26). Samples were assessed for electrical conductivity, ammonia, pH, and nitrite/nitrate. pH was measured after both deaeration with argon and CO(2) standardization. Additionally, the fraction of exhaled nitric oxide (FE(NO)) was assessed. Factor analysis was applied to identify major factors concerning these measures. Results: Three independent factors were detected; the first comprised conductivity, ammonia, and pH, especially when standardized using CO(2), the second nitrite/nitrate, and the third FE(NO). Conductivity and ammonia were highly correlated (r = 0.968; p < 0.001). FE(NO) provided independent information mainly in asthma. The nonspecific EBC markers showed considerable overlap between patient groups and healthy subjects. However, conductivity, ammonia, pH standardized for CO(2) and nitrite/nitrate were increased in LTX recipients compared to healthy controls (p < 0.05 each). Conclusions: A panel of nonspecific easy-to-obtain exhaled breath markers could be reduced to 3 independent factors. The information content of conductivity, ammonia, and pH after CO(2) equilibration appeared to be similar, while FE(NO) was independent. The increased levels of these biomarkers in LTX might indicate a potential for their use in these patients. Copyright (C) 2010 S. Karger AG, Base

Association between environmental factors and current asthma, rhinoconjunctivitis and eczema symptoms in school-aged children from Oropeza Province - Bolivia: a cross-sectional study

Background: In recent years, the prevalence of asthma, rhinoconjunctivitis and eczema symptoms in childhood has considerably increased in developing countries including Bolivia, possibly due to changes in lifestyle, environmental and domestic factors. This study aimed to assess the association between environmental factors and asthma, rhinoconjuctivitis and eczema symptoms in school-aged children from Oropeza Province in Chuquisaca, Bolivia. Methods: A cross-sectional study was performed in 2340 children attending the fifth grade in 36 randomly selected elementary schools in Oropeza province. The prevalence of symptoms was determined using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Environmental factors were assessed by the ISAAC environmental questionnaire including questions related to exposure to pets, farm animals, indoor and outdoor pollution, presence of disease vectors at home and precarious household conditions. Generalized linear mixed-effects models were adjusted for age, sex and place of living. Results: Thirty seven percent of children reported that at least one of their parents smoked at home. Wood or coal was used as cooking fuel in 19\% of the homes and 29\% reported intense truck traffic on the street where they lived. With respect to hygiene conditions, 86\% reported exposure to dogs, 59\% exposure to cats and 36\% regular contact to farm animals. More than one precarious household condition was reported by 8\% of children. In the adjusted model exposure to dog (adjusted OR 1.4; CI 95\% 1.0-1.9), cat (1.2; 1.0-1.5), farm animals (1.5; 1.2-1.8); intense truck traffic (1.3; 1.0-1.6), parents smoking at home (1.2; 1.0-1.5), presence of disease vectors at home (fourth quartile vs. first quartile: 1.6; 1.2-2.3) and two or more precarious household conditions (1.5; 1.0-2.2) were significantly associated with rhinoconjunctivitis symptoms. The associations were similar for asthma and eczema symptoms; however it did not reach the level of statistical significance for all items. Conclusion: Our results support previous findings reported for poor communities especially in Latin America, showing that lower hygiene conditions did not have protective effect against asthma and rhinoconjunctivitis and eczema symptoms

Prevalence of asthma, rhinitis and eczema symptoms in rural and urban school-aged children from Oropeza Province - Bolivia: a cross-sectional study

Background: Asthma and allergies are world-wide common chronic diseases among children and young people. Little information is available about the prevalence of these diseases in rural areas of Latin America. This study assesses the prevalence of symptoms of asthma and allergies among children in urban and rural areas at Oropeza Province in Bolivia. Methods: The Spanish version of the ISAAC standardized questionnaire and the ISAAC video questionnaire were implemented to 2584 children attending the fifth elementary grade in 36 schools in Oropeza province (response 91%). Lifetime, 12 months and severity prevalence were determined for asthma, rhinitis and eczema symptoms. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated adjusting for age using generalized linear mixed-effects models. Results: Median age of children was 11 years, 74.8% attended public schools, and 52.1% were female. While children attending urban schools had lower prevalence of self-reported wheeze in the written questionnaire (adjusted OR 0.6; 95% CI 0.4-1.9), they were more likely than children attending rural schools to report wheeze in the video questionnaire (aOR 2.1; 95% CI 1.0-2.6). They also reported more frequently severe rhinoconjunctivitis (aOR 2.8; 95% CI 1.2-6.6) and severe eczema symptoms (aOR 3.3; 95% CI 1.0-11.0). Conclusion: Overall in accordance with the hygiene hypothesis, children living in urban areas of Bolivia seem to have a higher prevalence of symptoms of asthma and allergies compared to children living in the country side. In order to develop primary prevention strategies, environmental factors need to be identified in future studies

An engineered Tetrahymena tRNA(Gln) for in vivo incorporation of unnatural amino acids into proteins by nonsense suppression

A new tRNA, THG73, has been designed and evaluated as a vehicle for incorporating unnatural amino acids site-specifically into proteins expressed in vivo using the stop codon suppression technique. The construct is a modification of tRNAGln(CUA) from Tetrahymena thermophila, which naturally recognizes the stop codon UAG. Using electrophysiological studies of mutations at several sites of the nicotinic acetylcholine receptor, it is established that THG73 represents a major improvement over previous nonsense suppressors both in terms of efficiency and fidelity of unnatural amino acid incorporation. Compared with a previous tRNA used for in vivo suppression, THG73 is as much as 100-fold less likely to be acylated by endogenous synthetases of the Xenopus oocyte. This effectively eliminates a major concern of the in vivo suppression methodology, the undesirable incorporation of natural amino acids at the suppression site. In addition, THG73 is 4-10-fold more efficient at incorporating unnatural amino acids in the oocyte system. Taken together, these two advances should greatly expand the range of applicability of the in vivo nonsense suppression methodology

Elimination kinetics of diisocyanates after specific inhalative challenges in humans: mass spectrometry analysis, as a basis for biomonitoring strategies

Background: Isocyanates are some of the leading occupational causes of respiratory disorders, predominantly asthma. Adequate exposure monitoring may recognize risk factors and help to prevent the onset or aggravation of these aliments. Though, the biomonitoring appears to be most suitable for exposure assessment, the sampling time is critical, however. In order to settle the optimal time point for the sample collection in a practical biomonitoring approach, we aimed to measure the elimination of isocyanate urine metabolites. Methods: A simple biomonitoring method enabling detection of all major diamine metabolites, from mono-, poly- and diisocyanates in one analytical step, has been established. Urine samples from 121 patients undergoing inhalative challenge tests with diisocyanates for diagnostic reasons were separated by gas chromatography and analyzed with mass spectrometry (GC-MS) at various time points (0-24 h) after the onset of exposure. Results: After controlled exposures to different concentrations of diisocyanates (496 +/- 102 ppb-min or 1560 +/- 420 ppb-min) the elimination kinetics (of respective isocyanate diamine metabolites) revealed differences between aliphatic and aromatic isocyanates (the latter exhibiting a slower elimination) and a dose-response relationship. No significant differences were observed, however, when the elimination time patterns for individual isocyanates were compared, in respect of either low or high exposure or in relation to the presence or absence of prior immunological sensitization. Conclusions: The detection of isocyanate metabolites in hydrolyzed urine with the help of gas chromatography combined with mass spectrometric detection system appears to be the most suitable, reliable and sensitive method to monitor possible isocyanate uptake by an individual. Additionally, the information on elimination kinetic patterns must be factored into estimates of isocyanate uptake before it is possible for biomonitoring to provide realistic assessments of isocyanate exposure. The pathophysiological elimination of 1,6-hexamethylene diamine, 2,4-diamine toluene, 2,6-diamine toluene, 1,5-naphthalene diamine, 4,4'-diphenylmethane diamine and isophorone diamines (as respective metabolites of: 1,6-hexamethylene diisocyanate, 2,4-toluene diisocyanate and 2,6 toluene diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate and isophorone diisocyanates) differs between individual isocyanates' diamines