| 1. |
- Joos, G. F., et al.
(författare)
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Indirect airway challenges
- 2003
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Ingår i: Eur Respir J. ; 21:6
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Tidskriftsartikel (refereegranskat)abstract
- Indirect challenges act by causing the release of endogenous mediators that cause the airway smooth muscle to contract. This is in contrast to the direct challenges where agonists such as methacholine or histamine cause airflow limitation predominantly via a direct effect on airway smooth muscle. Direct airway challenges have been used widely and are well standardised. They are highly sensitive, but not specific to asthma and can be used to exclude current asthma in a clinic population. Indirect bronchial stimuli, in particular exercise, hyperventilation, hypertonic aerosols, as well as adenosine, may reflect more directly the ongoing airway inflammation and are therefore more specific to identify active asthma. They are increasingly used to evaluate the prevalence of bronchial hyperresponsiveness and to assess specific problems in patients with known asthma, e.g. exercise-induced bronchoconstriction, evaluation before scuba diving. Direct bronchial responsiveness is only slowly and to a modest extent, influenced by repeated administration of inhaled steroids. Indirect challenges may reflect more closely acute changes in airway inflammation and a change in responsiveness to an indirect stimulus may be a clinically relevant marker to assess the clinical course of asthma. Moreover, some of the indirect challenges, e.g. hypertonic saline and mannitol, can be combined with the assessment of inflammatory cells by induction of sputum.
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| 2. |
- Sydbom, A, et al.
(författare)
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Health effects of diesel exhaust emissions
- 2001
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 17:4, s. 733-746
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies have demonstrated an association between different levels of air pollution and various health outcomes including mortality, exacerbation of asthma, chronic bronchitis, respiratory tract infections, ischaemic heart disease and stroke. Of the motor vehicle generated air pollutants, diesel exhaust particles account for a highly significant percentage of the particles emitted in many towns and cities. This review is therefore focused on the health effects of diesel exhaust, and especially the particular matter components. Acute effects of diesel exhaust exposure include irritation of the nose and eyes, lung function changes, respiratory changes, headache, fatigue and nausea. Chronic exposures are associated with cough, sputum production and lung function decrements. In addition to symptoms, exposure studies in healthy humans have documented a number of profound inflammatory changes in the airways, notably, before changes in pulmonary function can be detected. It is likely that such effects may be even more detrimental in asthmatics and other subjects with compromised pulmonary function. There are also observations supporting the hypothesis that diesel exhaust is one important factor contributing to the allergy pandemic. For example, in many experimental systems, diesel exhaust particles can be shown to act as adjuvants to allergen and hence increase the sensitization response. Much of the research on adverse effects of diesel exhaust, both in vivo and in vitro, has however been conducted in animals. Questions remain concerning the relevance of exposure levels and whether findings in such models can be extrapolated into humans. It is therefore imperative to further assess acute and chronic effects of diesel exhaust in mechanistic studies with careful consideration of exposure levels. Whenever possible and ethically justified, studies should be carried out in humans.
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