1/7. Significant changes in nonspecific bronchial responsiveness after isolated immediate bronchospecific reactions caused by isocyanates but not after a late reaction caused by plicatic acid.Although late bronchospastic reactions after exposure to antigenic and sensitizing agents usually significantly alter bronchial responsiveness to histamine or methacholine, presumably by causing bronchial inflammation, isolated immediate bronchospastic reactions do not induce such changes. We studied three subjects who demonstrated different patterns of reaction. The first individual was diagnosed as having occupational asthma to red cedar. This was confirmed by specific inhalation challenges that resulted in late bronchospastic reaction. No significant changes in the provocative concentration of histamine causing a 20% fall in FEV1 (PC20) were found 1 day after this reaction. Two weeks later, serial assessments (five and six, respectively) of PC20 histamine were recorded on control days and up to 48 hours after exposure to plicatic acid, which caused a late bronchospastic reaction with a maximum fall of 37% in FEV1. No significant changes in PC20 were found; the maximum variations on control days were 0.36 to 0.74 mg/ml, and on active days, from 0.37 to 0.59 mg/ml. By contrast, two other subjects, who demonstrated isolated immediate reactions after exposure to diphenylmethane diisocyanate, had significant changes in PC20 histamine and methacholine, in one subject from 3.1 mg/ml to 0.6 mg/ml 8 hours after exposure, and in the other subject, from 61.0 to 7.4 mg/ml 7 hours after exposure, with recovery during the next few days. These examples demonstrate that the pattern of nonspecific bronchial responsiveness after immediate and late bronchospastic reactions can be different from what has previously been described. Immediate bronchospastic reactions may lead to bronchial hyperresponsiveness, whereas late asthmatic reactions do not always induce changes in bronchial responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)- - - - - - - - - - ranking = 1keywords = cedar (Clic here for more details about this article) |
2/7. Bronchial reactivity in Western red cedar induced asthma.A patient with Western red cedar induced asthma is described. The diagnosis was confirmed by a bronchial challenge with Western red cedar saw dust and the subsequent prolonged bronchial reactivity changes were measured using histamine inhalation tests.- - - - - - - - - - ranking = 6keywords = cedar (Clic here for more details about this article) |
3/7. Exposure to a sensitizing occupational agent can cause a long-lasting increase in bronchial responsiveness to histamine in the absence of significant changes in airway caliber.A 58-year-old subject with a history of occupational asthma to red-cedar sawdust underwent specific inhalation challenges with this product. Significant increases in airway responsiveness to histamine (tenfold fall in PC20 FEV1) were documented 7 hours after exposure for 5 minutes to red cedar while baseline spirometry remained unchanged. A dual asthmatic reaction was induced during the following days by exposing the subject to red-cedar sawdust for 30 minutes and plicatic acid for 7 minutes. After recovery of PC20, the subject was reexposed to plicatic acid for 15 and 30 seconds on 2 consecutive days. No significant changes in FEV1, forced vital capacity, and residual volume were demonstrated in the following 8 hours, although minimal changes in forced expiratory flow rate between 25% and 75% of FVC were observed. PC20 dropped significantly and required 2 weeks to recover. This example illustrates that bronchial hyperresponsiveness to histamine can precede the changes in airway caliber after an antigen challenge. It also demonstrates that such changes can persist for up to 2 weeks after the challenge, even when no significant changes in FEV1 are induced.- - - - - - - - - - ranking = 3keywords = cedar (Clic here for more details about this article) |
4/7. Occupational asthma caused by eastern white cedar (thuja occidentalis) with demonstration that plicatic acid is present in this wood dust and is the causal agent.A worker developed symptoms of work-related asthma a few weeks after starting to work in a sawmill where eastern white cedar (thuja occidentalis) was transformed into shingles. The diagnosis of occupational asthma was confirmed by monitoring of peak expiratory flow rates and bronchial responsiveness to histamine off work and at work, and specific inhalation challenges in the laboratory that demonstrated an isolated late asthmatic reaction after exposure for 4 hours to the wood dust. Specific inhalation challenges with western red cedar (thuja plicata) for 2 hours and plicatic acid (PA) for 7 minutes also caused an isolated late asthmatic reaction. Elevated specific IgE levels to PA were present. Antiserum was produced in rabbits that were immunized with PA conjugated to human serum albumin. With this antiserum in inhibition experiments, cross-reactivity between western red cedar and eastern white cedar, both belonging to the family of arborvitae, was found. It is estimated that eastern white cedar contains approximately half the amount of PA present in western red cedar.- - - - - - - - - - ranking = 10keywords = cedar (Clic here for more details about this article) |
5/7. Recurrent nocturnal asthma after bronchoprovocation with Western Red Cedar sawdust: association with acute increase in non-allergic bronchial responsiveness.Recurrent nocturnal asthma following a single exposure to Western Red Cedar sawdust was documented by measurements of peak flow rates in two sensitized subjects. The nocturnal asthma followed a dual asthmatic response in the first subject and a late (non-immediate) asthmatic response in the second. Both subjects developed a 10-fold reduction in the dose of histamine required to decrease the FEV1 by 20%. This cedar-induced increase in non-specific bronchial reactivity was maximal at the time of the recurrent nocturnal asthma, and persisted after nocturnal asthma had ceased and after FEV1 had returned to normal. We hypothesize that the enhanced non-specific bronchial reactivity which occurs following late asthmatic responses to bronchial challenge is the cause of recurrent nocturnal asthma following single exposure to a sensitizing agent.- - - - - - - - - - ranking = 1keywords = cedar (Clic here for more details about this article) |
6/7. Occupational asthma caused by cedar urea formaldehyde particle board.Two carpenters developed asthma and rhinitis related to occupational exposure to a cedar urea formaldehyde (CUF) particle board. One patient developed nasal and chest symptoms and an equivocal early asthmatic response after CUF sawdust exposure, but not after spruce or western red cedar sawdust exposure; possible late asthmatic response may have been inhibited by beclomethasone treatment. The other patient developed marked nasal and chest symptoms and a dual asthmatic response after CUF exposure, but not after spruce or cedar exposure. Both patients developed increased bronchial responsiveness to inhaled histamine, which persisted for at least six days in the first patient, and which was associated with increased asthmatic symptoms of days' to weeks' duration in both. A previously unexposed asthmatic patient, with more markedly hyperreactive bronchi, developed no symptoms, no change on spirometric testing, and no change in histamine response after CUF exposure. Specific IgE antibodies directed against formaldehyde-human serum albumin conjugate could not be demonstrated using the radioallergosorbent test. This investigation documents the occurrence of occupational asthma caused by urea formaldehyde used as a bonding agent in particle boards. Absence of a response in a previously unexposed, more severe asthmatic patient suggests specific sensitization to some component of the urea formaldehyde resin complex had developed.- - - - - - - - - - ranking = 7keywords = cedar (Clic here for more details about this article) |
7/7. Respiratory tract reactions to western red cedar.1 asthma due to western red cedar (thuja plicata) is well recognized, but has not been described frequently in the UK. Two patients who developed asthma and rhinitis due to occupational contact with western red cedar were studied. Both patients developed late asthmatic responses following bronchial challenge with western red cedar. 2 The challenge technique and the results of comparison between different wood dusts and dust extract are described. 3 The technique of anterior rhinometry was used to follow the nasal response to challenge in one patient, and demonstrated a late nasal reaction which followed a similar time course to the bronchial response.- - - - - - - - - - ranking = 7keywords = cedar (Clic here for more details about this article) |