Several studies on the prognosis of occupational asthma have shown that a significant proportion of patients continue to experience asthmatic symptoms and nonspecific bronchial hyperresponsiveness after cessation of work. The determinants of this unfavourable prognosis of asthma are: long duration of exposure before the onset of asthma; long duration of symptoms before diagnosis; baseline airway obstruction; dual response after specific challenge test; and the persistence of markers of airway inflammation in bronchoalveolar lavage fluid and bronchial biopsy. The relevance of immunological markers in the outcome of occupational asthma has not yet been assessed. Further occupational exposure in sensitized subjects leads to persistence and sometimes to progressive deterioration of asthma, irrespective of the reduction of exposure to the specific sensitizer, and only the use of particular protective devices effectively prevents the progression of the disease. A long-term follow-up study of toluene diisocyanate (TDI)-induced asthma showed that the improvement in bronchial hyperresponsiveness to methacholine occurred in a small percentage of subjects and only a long time after work cessation. Bronchial sensitivity to TDI may disappear, but non-specific bronchial hyperresponsiveness often persists unchanged, suggesting a permanent deregulation of airway tone. Steroid treatment significantly reduces nonspecific bronchial hyperresponsiveness only when started immediately after diagnosis.
Last. Carlo Giuntini(UniPi: University of Pisa)H-Index: 46
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Long-term change in nonspecific and specific bronchial hyperresponsiveness was studied in 16 subjects with asthma induced by toluene diisocyanate (TDI). A significant positive correlation between months of follow-up and provocative dose inducing a 20 percent fall in FEV 1 (PD 20 FEV 1 ) methacholine was observed in 5 of 16 subjects. In 4 of these 5 subjects, a PD 20 FEV 1 >1 mg of methacholine was observed 30 to 48 months after the end of TDI exposure. In most subjects, nonspecific bronchial hyp...
Four workers from a cedar sawmill who developed red cedar asthma are described. They had serial measurements of lung function and nonspecific bronchial hyperresponsiveness (NSBH) several years before and after the development of chest symptoms. Measurements of dust concentration and specific IgE antibodies to plicatic acid-human serum albumin (PA-HSA) conjugate were also carried out before the onset of disease. NSBH developed in parallel with the development of asthma and was not present in any ...
The effect of cessation of exposure to toluene diisocyanate (TDI) was studied in six patients with TDI-induced asthma, proved by a positive inhalation challenge with TDI. Bronchial challenges with TDI and methacholine were performed, and lobar bronchial biopsies were taken at diagnosis and 6 months later, after cessation of exposure. Biopsies from four nonasthmatic control subjects were also examined. At diagnosis, asthmatic subjects had thickened reticular basement membrane (p < 0.05) and incre...
To evaluate the morphologic basis of the different outcomes of toluene diisocyanate (TDI) asthma after quitting occupational exposure, we examined ten patients with TDI asthma who showed, at diagnosis, a positive TDI challenge test and nonspecific bronchial hyperresponsiveness (NSBH) to methacholine. After diagnosis, all patients ceased work and a 4- to 40-month follow-up was obtained with three to eight determinations of the cumulative dose producing a 15 percent fall in FEV1 (PD15FEV1) methach...
After an average follow-up of 6.5 yr (range 1 to 13), 48 of 68 patients with cedar asthma, who were still working in the same industry, were re-examined. In all of them, the diagnosis of cedar asthma had been confirmed with a specific challenge inhalation test with plicatic acid. We graded the severity of asthma symptoms and the requirement for antiasthma medications at the time of diagnosis and at the time of follow-up visit. Spirometry and measurement of airway responsiveness to methacholine (...
We have previously shown that in some subjects with occupational asthma caused by various agents, there is no improvement approximately two years after exposure ended. These results could be explained by the short interval between diagnosis and follow-up. In the current study, we1 saw 28 subjects with occupational asthma at two intervals, 2.3 years (range, three months to 5.7 years) and 5.8 years (range, 4.3 to 10.9 years) after the cessation of exposure. Various causes of occupational asthma we...
Thirty-one workers with occupational asthma caused by snow-crab processing were assessed by a long-term follow-up on three occasions at mean ± SD intervals of 12.8 ± 5.4, 31.4 ± 6.3, and 64.4 ± 6.3 months after leaving work. The diagnosis of work-related asthma was initially confirmed in all of them by specific inhalation challenges at the workplace or by laboratory inhalation of snow-crab boiling water (n = 24) or by serial monitoring of airway caliber and bronchial responsiveness to histamine ...
Thirty-five subjects with occupational asthma due to toluene diisocyanate (TDI) exposure were examined. All the subjects were studied with inhalation challenges with TDI and with methacholine. TDI asthma was documented by a positive inhalation challenge to low levels of TDI. Airway responsiveness to methacholine was in the range of asthmatic patients at the time of diagnosis. After an average follow-up interval of 10 months, all the subjects were re-examined. Of the 35 subjects examined, 30 subj...
#1Shuyu Chen(Southern University of Science and Technology)
#2Zhuoyu Chen(Beijing University of Chinese Medicine)
Last. Rongchang Chen(Southern University of Science and Technology)H-Index: 2
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Abstract null null Background null Accumulating evidence indicated the crucial role for interleukin 6 (IL-6) signaling in the development of allergic asthma. Yet, the role of IL-6 signaling in toluene diisocyanate (TDI)-induced mixed granulocytic airway inflammation still remains unclear. Thus, the aims of this study were to dissect the role of IL-6 signaling and to evaluate the effect of tocilizumab on TDI-induced steroid-resistant asthma. null null null Methods null TDI-induced asthma model wa...
Last. Haixiong Tang(Southern Medical University)H-Index: 7
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Abstract TDI-induced asthma is characterized by neutrophil-dominated airway inflammation and often associated with poor responsiveness to steroid treatment. Both PI3Kδ and PI3Kγ have been demonstrated to play important proinflammatory roles in ovalbumin-induced asthma. We’ve already reported that blocking pan PI3K effectively attenuated TDI-induced allergic airway inflammation. Yet the specific functions of PI3Kδ and PI3Kγ in TDI-induced asthma are still unclear. Male BALB/c mice were first derm...
Unani Medicine, being one of the oldest systems of medicine has very vast literature and has played an important role in the understanding of the diseases and their management and still provides some remarkable solutions to the different diseases, Bronchial Asthma is one of them. Asthma is one of the most chronic prevalent diseases in children as well as in adults. The clinical description of Asthma dates back to ancient times and, over this long period, multiple paradigms for asthma pathogenesi...
#1Rongchang Chen(Guangzhou Medical University)H-Index: 26
#2Qingling Zhang(Guangzhou Medical University)H-Index: 53
Last. Lihong Yao(Guangzhou Medical University)H-Index: 4
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Steroid insensitivity constitutes a major problem for asthma management. Toluene diisocyanate (TDI) is one of the leading allergens of asthma that induces both T-helper Th2 and Th17 responses, and is often associated with poor responsiveness to steroid treatment in the clinic. We sought to evaluate the effects of inhaled and systemic steroids on a TDI-induced asthma model and to find how interleukin (IL)-17A and IL-17F function in this model. BALB/c mice were exposed to TDI for generating an ast...
Last. Dhimiter Bello(University of Massachusetts Lowell)H-Index: 31
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Biomonitoring of methylene diphenyl diisocyanate (MDI) in urine may be useful in industrial hygiene and exposure surveillance approaches toward disease (occupational asthma) prevention and in understanding pathways by which the internalized chemical is excreted. We explored possible urine biomarkers of MDI exposure in mice after respiratory tract exposure to MDI, as glutathione (GSH) reaction products (MDI–GSH), and after skin exposure to MDI dissolved in acetone. LC–MS analyses of urine identif...
Last. Arif Cimrin(Dokuz Eylül University)H-Index: 14
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OBJECTIVE: Occupational diseases (OD) are among the most significant issues of work life, with economic, medical, social, and ethical aspects. The majority of studies concerning OD focus on the causes or medical outcomes of OD. There are a limited number of studies investigating the social and economic impacts of being diagnosed with an OD. One of the important social aspects of OD is the employability of workers after an OD diagnosis. The aim of this study is to evaluate the changes in employme...
#1E. von Mutius(LMU: Ludwig Maximilian University of Munich)H-Index: 71
Die Epidemiologie ist eine wichtige Disziplin, um die Morbiditat, Mortalitat, Variabilitat uber Raum und Zeit sowie den naturlichen Verlauf allergischer Erkrankungen zu beschreiben. Daruber hinaus tragt die Epidemiologie zur Ursachenforschung bei, da sie genetische wie umweltbedingte Determinanten allergischer Erkrankungen identifiziert und charakterisiert. Auch wenn sie Ursachen nicht beweisen kann, so sind epidemiologische Beobachtungen doch haufig Ausgangspunkt weiterer experimenteller Unters...
Last. Philip Harber(UofU: University of Utah)H-Index: 29
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Summarize developed evidence-based diagnostic and treatment guidelines for work-related asthma (WRA).Comprehensive literature reviews conducted with article critiquing and grading. Guidelines developed by a multidisciplinary expert panel and peer-reviewed.Evidence supports spirometric testing as an essential early test. Serial peak expiratory flow rates measurement is moderately recommended for employees diagnosed with asthma to establish work-relatedness. Bronchial provocation testing is modera...
Occupational asthma (OA) is associated with an estimated annual societal cost in the UK of £100 million, which is avoidable if workers are identified quickly and removed from exposure to a sensitizing agent. The aim of this work was to identify barriers to diagnosing OA on the part of workers and healthcare professionals. The first study evaluated current practice in assessing working-age asthmatics for OA in a West Midlands primary care population. There was poor enquiry regarding occupation (1...
Aim: To evaluate the clinical outcome and socioeconomic consequences of occupational asthma (OA). Subjects and methods: Twenty-five patients with OA both to high- and low-molecular-weight agents (3 and 22, respectively) confirmed by specific inhalation challenge were followed up for 12 months after the diagnosis. Upon diagnosis, each patient received a diary on which to report peak expiratory flow rate (PEFR), symptoms, drug consumption, expenses directly or indirectly related to the disease, as...
