Intestinal-Type Adenocarcinoma of the Sinonasal Tract: A Clinicopathologic Study of 18 Cases

Background

Intestinal-type adenocarcinoma (ITAC) of the nose and paranasal sinuses is a relatively rare tumor. It commonly affects subjects exposed to wood or leather dust.

Methods

The authors present the clinicopathologic findings of 18 cases of sinonasal ITACs and review the proposed histologic classifications.

Results

All patients, except one, were males; mean age was 60 years (range, 41-79); in 9 cases an occupational exposure to wood or leather dust was found. Common presenting symptoms were epistaxis, nasal obstruction and rhinorrhea. Histologically, tumors were divided into four groups: well-differentiated (G1) ITACs = 3 cases; moderately differentiated (G2) ITACs = 8 cases; poorly differentiated (G3) ITACs = 2 cases; mucinous (M) ITACs = 5 cases. Immunocytochemically, 16/17 cases were positive for carcinoembryonal antigen, 1/17 for somatostatin, and 0/16 cases for gastrin.

Conclusions

Sinonasal ITACs are aggressive tumors, often diagnosed in a relatively advanced stage. Owing the close similarity of the microscopic aspects, a histologic classification of ITACs analogous to that of colonic adenocarcinomas is proposed.

The influence of a central vacuum system on quality life in patients with house dust-associated allergic rhinitis

Indoor pollution is one of the most common problems addressed by allergists and troublesome for their patients. Although a large variety of products are available for removing such pollutants, including house dust, there is a relative paucity of data on the effectiveness of such devices. In many cases, central vacuum systems are recommended, particularly in new homes. To specifically address the question of whether a central vacuum system produces an improvement in the well characterized domains of Juniper Rhinoconjunctivitis Quality of Life Questionnaire, we selected 25 individuals with a history of documented type I hypersensitivity to house dust. Each of these individuals used either a Beam Central Vacuum System or their own conventional vacuum for a period of 3 months. At the end of this period, the individual switched over to the opposite limb of the study for 3 additional months. Interestingly, in all seven domains of the evaluation, including activity, sleep, nonnasal symptoms, practical problems, nasal symptoms, eye symptoms and emotions, use of the central vacuum proved to be superior.

[Characteristics of work environment factors and health state of workers engaged in open mining of refractory clay and structural quartz sand]

This article covers evaluation of work conditions and health state in workers engaged into open-cast extraction of refractories and of building quartz sand in moderate climate of Voronezh region.

[Complex hygienic evaluation of drivers' work conditions]

Drivers' work is characterized by various occupational hazards--higher psychoemotional strain associated with risk of traffic accidents, unfavorable microclimate, dusty and polluted air, static physical load.

[Occupational medicine in present-day furniture production]

Work conditions in furniture production are characterized by complex of occupational hazards: dusty and polluted air, local vibration, noise, static physical strain.

[Work conditions and health of workers engaged in textile production]

Textile industry is characterized by higher share of women involved (up to 80%), early start of employment (since 15 years of age, with consideration of professional training)--that requires hygienists' special attention to the problem.

[Main difficulties and advances in State sanitary and epidemiological supervision of occupational health in Voronezh region]

Creation of favorable work conditions necessitates gradual change-over to their specification on major industrial workplaces with intensive occupational hazards.

Early sensitization to house dust mite is a major risk factor for subsequent development of bronchial asthma in Japanese infants with atopic dermatitis: results of a 4-year followup study

BACKGROUND

Bronchial asthma (BA) often develops in children with atopic dermatitis (AD). Identification of factors that could predict the development of asthma in children with AD is useful for early intervention.

OBJECTIVE

We undertook a 4-year followup study to clarify the factors involved in the development of BA in infants with AD.

METHODS

We registered 169 infants with AD who were free of BA at registration and examined the prevalence and characteristics of the subsequent development of BA among these patients.

RESULTS

Among the patients followed for 4 years, approximately 45% experienced asthma-like respiratory symptoms, and 35% were diagnosed as asthmatic patients by pediatric allergologists. Patients who developed BA showed early appearance of house dust mite (HDM)-specific immunoglobulin E (IgE) and persistently high levels of food-specific IgE. Male sex, a positive family history of BA, and the appearance of HDM-specific IgE were identified as significant risk factors for the early development of BA, but the significance of these parameters decreased thereafter. A positive family history of AD, the outcome of skin lesions, and keeping furred pets were also identified as risk factors in a part of the followup period. Among the parameters examined, the early appearance of HDM-specific IgE was the most significant risk factor.

CONCLUSION

Appearance of HDM-specific IgE antibodies in early childhood, which seems to be mainly influenced by genetic factors, is a major risk factor for the subsequent development of BA in children with AD, but the influence decreases after longer followup.

[IL-10 serum levels in children with moderate asthma]

Levels of an interleukin 10 (IL-10) are reduced in asthmatic patients in comparison to healthy subjects. Fact, that IL-10 is produced by Th1 and that inhibits cytokine production by Th2 lymphocytes has led to the concept that IL-10 might be beneficial in mitigating allergic inflammation. The purpose of this study was to define the effect of 4 week monotherapy with triamcinolone acetonide or nedocromil sodium on the serum level of IL-10, bronchial hyperresponsiveness and clinical parameters in atopic asthma children. It was an 8 week, randomised, double-blind trial of 37 children with moderate asthma allergic to house dust mite. Patients were randomly allocated to receive 200 mcg triamcinolone twice daily (n = 18), or 0.004 g nedocromil four times daily (n = 19). Thirty children completed the study. After treatment with triamcinolone the level of IL-10 in blood serum significantly increased, bronchial hyperreactivity significantly decreased, and all clinical parameters improved. Mean IL-10 levels in serum before and after treatment with triamcinolone were 7.5 pg/ml with 95%CI 6.79%-8.22% and 14.21 pg/ml with 95%CI 11.33%-17.09% respectively (p < 0.001). After treatment with nedocromil, clinical symptoms improved significantly, IL-10 serum levels and bronchial hyperreactivity did not change significantly (p = 0.094 and p = 0.09 respectively). This study demonstrates that one possible way by which triamcinolone contribute to inhibition of inflammation is by effect on IL-10.

[Non-occupational dust exposure of the population living in the vicinity of amphibolite mining and processing plant]

Amphibolite bed working in a strip mine, material processing, storage and waste disposal are associated with dust emission to the environment. The aim of our study was to assess non-occupational exposure to dust of people living in a village located about 200 m away from the mine. The fallout dust and the sediment obtained from water samples collected from the stream were found to contain tremolite. Respirable mineral fibers were detected in dust samples collected by filtration of the atmospheric air. Mean 24-h concentrations of the respirable dust at the place of measurements (school) varied considerably, from 11 micrograms/m3 to 20,059 micrograms/m3. The highest dust concentrations were found during the third shift. As fibrous contaminants were detected in many mines of the Lower Silesia region, it is necessary to assess the non-occupational exposure of populations living close to all mines in this area.

Acute eosinophilic pneumonia in a New York City firefighter exposed to World Trade Center dust

We report a sentinel case of acute eosinophilic pneumonia in a firefighter exposed to high concentrations of World Trade Center dust during the rescue effort from September 11 to 24. The firefighter presented with a Pa(O2) of 53 mm Hg and responded to oxygen and corticosteroids. Computed tomography scan showed patchy ground glass density, thickened bronchial walls, and bilateral pleural effusions. Bronchoalveolar lavage recovered 70% eosinophils, with only 1% eosinophils in peripheral blood. Eosinophils were not degranulated and increased levels of interleukin-5 were measured in bronchoalveolar lavage and serum. Mineralogic analysis counted 305 commercial asbestos fibers/10(6) macrophages including those with high aspect ratios, and significant quantities of fly ash and degraded fibrous glass. Acute eosinophilic pneumonia is a rare consequence of acute high dust exposure. World Trade Center dust consists of large particle-size silicates, but fly ash and asbestos fibers may be found in bronchoalveolar lavage cells.

Trimellitic anhydride (TMA) dust induces airway obstruction and eosinophilia in non-sensitized guinea pigs

Trimellitic anhydride (TMA) causes asthma after a latency period of sensitization. In non-sensitized humans and animals, limited studies indicate that TMA exposure may also cause symptoms of asthma without a latency period. Our previous studies (J. Pharmacol. Exp. Ther. 296 (2001) 284) in a guinea pig model of TMA-induced asthma demonstrated that sensitization and the complement system were required for eosinophilia. TMA conjugated to guinea pig serum albumin (TMA-GPSA) was used to elicit the response. Since occupational exposure to TMA occurs by inhalation of dust, the present studies determined if exposure to TMA dust in a non-sensitized guinea pig elicited airway obstruction and inflammation, and whether a significantly greater response occurred after a latency period of sensitization. Guinea pigs were intradermally injected with either corn oil (non-sensitized animals) or 30% TMA (sensitized animals). Three weeks later they were challenged by intratracheal insufflation with 1 mg TMA dust or lactose dust (control) using a dry powder delivery device. Pulmonary resistance, dynamic lung compliance, mean arterial blood pressure and heart rate were monitored for 10 min. In non-sensitized guinea pigs, significant increases in pulmonary resistance and decreases in dynamic lung compliance and blood pressure occurred after TMA challenge. In sensitized animals, the same dose of TMA caused significantly greater effects compared to non-sensitized animals. In a separate experiment, cellular infiltration into the lung was determined 24 h after challenge with TMA dust or lactose dust. In both non-sensitized and sensitized animals, eosinophils in the lung tissue were increased after TMA dust challenge compared to controls. Thus, these studies suggest that the response in non-sensitized animals differs depending on whether TMA dust or TMA-GPSA is used to elicit the response. TMA dust elicits significant airway obstruction and eosinophilia in a non-sensitized animal, with even greater airway obstruction occurring in a sensitized animal.

Clinical evaluation of the effect of anti-allergic mattress covers in patients with moderate to severe asthma and house dust mite allergy: a randomised double blind placebo controlled study

BACKGROUND

The use of anti-allergic mattress covers in patients with asthma can result in a large reduction in the level of house dust mite allergen in dust samples. Apart from a reduction in histamine induced bronchial hyperresponsiveness, there are few data on the effect of mattress covers on clinical efficacy and quality of life in patients with moderate to severe asthma.

METHODS

Thirty patients with asthma and house dust mite allergy were studied in a randomised, double blind, placebo controlled study. Before and after using anti-allergic covers for 1 year, dust was collected from the mattresses to determine concentrations of Dermatophagoides pteronyssinus (Der p 1), and bronchial hyperresponsiveness and quality of life were measured. The patients scored their symptoms (lungs and nose), morning and evening peak flow values, and rescue medication for 14 days before and after the intervention period.

RESULTS

There was a significant reduction in the concentration of Der p 1 in the dust collected from the mattresses in the actively treated group after 1 year compared with before treatment; no change was found in the placebo group. In both the actively treated and placebo groups there was no significant improvement in PC(20) histamine. Quality of life improved similarly in both groups. The symptom score of the lower airways did not significantly change in either group. A significant decrease in nasal symptom score was seen in the actively treated group compared with before treatment, but there was no significant difference between the groups. No changes in morning and evening peak flow values, peak flow variability, nor in the use of rescue medication were found in either group.

CONCLUSION

The use of anti-allergic mattress covers results in significant reductions in Der p 1 concentrations in carpet-free bedrooms. However, in patients with moderate to severe asthma, airways hyperresponsiveness and clinical parameters are not affected by this effective allergen avoidance.

Effects in the eyes caused by exposure to office dust

This Danish Office Dust Experiment compares the responses of 24 normal non-sensitive adult subjects to exposure to normal office dust in the air at 136 and 390 micrograms/m3 (median) and to their responses in clean air. The exposure duration was 5 1/4 h in a climate chamber under controlled conditions. The dust had no major identifiable specific reactive compounds. The overall conclusion is that healthy subjects without any hypersensitive reactions seem to respond to exposure to the house dust. The effects observed were all found in interaction with response modifying factors. The effects were a decrease in inflammatory cells in tear fluids, increased epithelium defects, and a decrease in break-up time. No effect was seen on eye reddening, or eye sensitivity to CO2. As no specific hypotheses could be specified before the study for the observed interactions, no definitive conclusions can be made. Furthermore, it seemed that there was no consistency in the interacting factors after the exposure and the next morning. A tentative analysis of the effects of the importance of personal characteristics showed that only a minority within the subject group may respond to the exposure. However, no common set of sensitivity measures could be defined for these responders.

Induction of ferritin and lipid peroxidation by coal samples with different prevalence of coal workers' pneumoconiosis: role of iron in the coals

BACKGROUND

Differences in levels of bioavailable iron (BAI) in coal may be responsible for the observed regional differences in the prevalence and severity of coal workers' pneumoconiosis (CWP).

METHODS

Twenty-nine coal samples from three coal mine regions were tested in human lung epithelial Type II A549 cells. They were from Utah (UT), West Virginia (WV), and Pennsylvania (PA) with a prevalence of CWP of 4, 10, and 26%, respectively.

RESULTS

Low molecular weight (LMW) chelators bound iron, a fraction of BAI in the cells released from coals, ferritin, and lipid peroxidation were significantly higher in cells treated with various coals than in control cells, with an increasing order of UT < WV < PA, in parallel to the prevalence of CWP in these coal mine regions. Deferoxamine (DFO), a specific iron chelator, was used to distinguish effects of BAI from those of other transition metals. Our results indicate that BAI in the coals of WV and UT is the main metal species in inducing ferritin and lipid peroxidation. In contrast, biological effects of PA coals are not only from BAI, but from other transition metals as well.

CONCLUSIONS

Based on a large number of coal samples from various seams, the findings of this study provide further evidence that metals, particularly iron, play important roles in coal dust-induced cellular damage, ultimately leading to the development of CWP and contributing to the regional differences in the prevalence of the disease.

Effectiveness of a worksite intervention to reduce an occupational exposure: the Minnesota wood dust study

OBJECTIVES

This study assessed the effectiveness of an intervention to reduce wood dust, a carcinogen, by approximately 26% in small woodworking businesses.

METHODS

We randomized 48 businesses to an intervention (written recommendations, technical assistance, and worker training) or comparison (written recommendations alone) condition. Changes from baseline in dust concentration, dust control methods, and worker behavior were compared between the groups 1 year later.

RESULTS

At follow-up, workers in intervention relative to comparison businesses reported greater awareness, increases in stage of readiness, and behavioral changes consistent with dust control. The median dust concentration change in the intervention group from baseline to follow-up was 10.4% (95% confidence interval = -28.8%, 12.7%) lower than the change in comparison businesses.

CONCLUSIONS

We attribute the smaller-than-expected reduction in wood dust to the challenge of conducting rigorous intervention effectiveness research in occupational settings.

[Air pollution, asthma and allergy--the importance of different types of particles]

BACKGROUND

Particulate air pollution has been much discussed in Norway during the last few years. Coarse particles from asphalt are likely to have quite different properties than the far smaller particles from diesel exhaust.

MATERIALS AND METHODS

On the basis of data from the literature and our own research, we discuss the health problem of different types of particles with a focus on allergy and respiratory symptoms.

RESULTS

Diesel exhaust particles have well-documented adverse effects in relation to allergic airway disease. They increase symptoms load in already allergic individuals and also seem to contribute to the increased prevalence of allergy. PM10 is today measured on the basis of weight, not on number. Diesel exhaust particles are much smaller than road surface particles; hence PM10 measurements reflect road surface dust pollution more than exhaust particles.

INTERPRETATION

Focus should now be given to diesel exhaust particles in order to reduce the adverse health effects of particulate air pollution in Norwegian cities.

Differences in the effects of fibrous and particulate titanium dioxide on alveolar macrophages of Fischer 344 rats

Alveolar macrophages are considered to play a major role in the pathophysiology of lung diseases caused by exposure to various kinds of pathogens and particles. In this study, the cytotoxic effect of different shapes of titanium dioxide (TiO(2)) was evaluated on macrophages using a unique magnetometry method and was compared with conventional methods of lactate dehydrogenase (LDH) release, apoptosis measurement, and morphological observations. Alveolar macrophages obtained from Fischer rats (F344) by bronchoalveolar lavage were incubated in vitro for 18 h with Fe(3)O(4) as a magnetometric indicator and fibrous and particulate forms of TiO(2) as test materials. In the control and particulate exposed group, rapid attenuation of the residual magnetic field, so-called "relaxation," was observed immediately after cessation of the external magnetic field. In comparison, a delay of relaxation was observed in alveolar macrophages exposed to fibrous TiO(2). LDH released into serum-free medium induced by exposure to TiO(2) increased significantly in a concentration-dependent manner in macrophages exposed to fibrous TiO(2), while negligible LDH release was observed in macrophages exposed to particulate TiO(2). The DNA ladder detection method and morphological examination detected no apoptosis in macrophages exposed to 60 micro g/ml of fibrous or particulate TiO(2). Electron microscopic examination revealed vacuolar changes and cell surface damage in macrophages exposed to fibrous TiO(2), but no significant changes in macrophages exposed to particulate TiO(2). The results of magnetometry, LDH release, and electron microscopy suggest that cytotoxicity of TiO(2) depends on the shape of the material.

Placebo-controlled trial of house dust mite-impermeable mattress covers: effect on symptoms in early childhood

We investigated the effect of house dust mite (HDM)-allergen avoidance on the development of respiratory symptoms, atopic dermatitis, and atopic sensitization by performing a double blind, placebo-controlled trial. In total, 1,282 allergic pregnant women were selected (416 received HDM allergen-impermeable mattress covers for the parents' and child's mattress in the third trimester of pregnancy [active], 394 received placebo covers, 472 received no intervention). Data on allergen exposure, clinical symptoms, and immunoglobulin E were collected prospectively. The prevalence of night cough without a cold in the second year of life was lower in the group with active covers compared with the group with placebo covers (adjusted odds ratio 0.65; 95% confidence interval 0.4-1.0). No effect of the intervention was seen on other respiratory symptoms, atopic dermatitis, and total and specific immunoglobulin E. It can be concluded that application of HDM-impermeable mattress covers on the child's and parents' beds reduced night cough, but not other respiratory symptoms, atopic dermatitis, and atopic sensitization in the first 2 years of life. Follow-up will determine the long-term effect of the intervention on the development of atopic disease.

Occupational dust exposure and the risk of laryngeal cancer in Turkey

OBJECTIVES

A hospital-based case-referent study was conducted to identify occupational risk factors for laryngeal cancer. In a previous report an association was found between laryngeal cancer and occupations with potential dust exposure; a job-exposure matrix was developed to aid further evaluation of laryngeal cancer risks from five occupational dust exposures.

METHODS

Among 7631 cancer cases from the Okmeydani Hospital, Istanbul, between 1979 and 1984, 958 larynx cancer cases were identified among men. After exclusions, 940 laryngeal cancer cases and 1519 referents were available. A standardized questionnaire was used to obtain basic information on the patients. Seven-digit standard occupational and industrial codes were created to classify the job and industrial titles. A job-exposure matrix was developed for occupational dusts, including silica, asbestos, wood, cotton, and grain, and age-, smoking-, and alcohol-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate risks of laryngeal cancer.

RESULTS

An excess of laryngeal cancer occurred for workers potentially exposed to silica and cotton dust, particularly for supraglottic cancer (OR 1.8, 95% CI 1.3-2.3, for silica and OR 1.6, 95% CI 1.1-2.5, for cotton dust), and there was a significant dose-response relationship with silica exposure. No relationship was found between laryngeal cancer and asbestos, grain, or wood dust exposures.

CONCLUSION

Laryngeal cancer, especially supraglottic tumors, is associated with silica and cotton dust exposures in Turkey.

Personal exposure of Paris office workers to nitrogen dioxide and fine particles

AIMS

(1) To obtain an overall estimate of variability of personal exposure of Paris office workers to fine particles (PM(2.5)) and nitrogen dioxide (NO(2)), and to quantify their microenvironmental determinants. (2) To examine the role of potential determinants of indoor concentrations.

METHODS

Sixty two office workers in a Paris municipal administration (all non-smokers) were equipped with personal samplers: passive samplers for 48 hours for NO(2) (n = 62), and active pumps for 24 hours for PM(2.5) (n = 55). Simultaneous measurements were performed in homes and offices; the local air monitoring network provided ambient concentrations. A time activity diary was used to weight measured concentrations by time spent in each microenvironment in order to estimate exposure concentrations.

RESULTS

On average, PM(2.5) personal exposure (30.4 microg/m(3)) was higher than corresponding in-home (24.7 microg/m(3)) and ambient concentrations (16.7 microg/m(3)). Personal exposure to NO(2) (43.6 microg/m(3)) was significantly higher than in-home concentrations (35.1 microg/m(3)) but lower than the background outdoor level (60.1 microg/m(3)). Personal exposures to PM(2.5) and NO(2) were not significantly different from in-office concentrations. PM(2.5) and NO(2) personal exposures were not significantly correlated. In-home, in-office, in-transit, outdoor time weighted concentrations, and time spent in other indoor microenvironments explain respectively 86% and 78% of personal variations in PM(2.5) and NO(2). In-home PM(2.5) concentration was primarily influenced by exposure to environmental tobacco smoke, and secondly by the ambient level (R(2) = 0.20). NO(2) in-home concentration was affected mostly by the ambient level and gas cooking time (R(2) = 0.14).

CONCLUSION

While results show the major contribution of in-home and in-office concentrations to both NO(2) and PM(2.5) personal exposures, the identification of indoor level determinants was not very conclusive.

Dermatitis caused by physical irritants

BACKGROUND

Although physical irritant contact dermatitis (PICD) is a common occupational dermatosis, it is one of the least well understood because of its multiple types, lack of diagnostic test, and the many mechanisms involved in its production.

OBJECTIVES

To characterize the materials and mechanisms of physical irritation of the skin.

METHODS

We did a retrospective analysis over the past 20 years of all patients with a diagnosis of PICD at St John's Institute of Dermatology Contact Dermatitis Clinic.

RESULTS

Of the 29,000 patients who attended the clinic over the study period, 392 patients were diagnosed with PICD and of these, 335 files were analysed.

CONCLUSIONS

Our findings show that PICD accounted for 1.15% of all patients attending the contact clinic over the study period. Diverse occupations and materials were implicated. The most common cause of PICD was low humidity due to air-conditioning, which caused dermatitis of the face and neck in office workers due to drying out of the skin.

Asthma from inhalation of Triplochiton scleroxylon (Samba) wood dust

The inhalation of wood dust may produce allergic rhinitis, asthma, or contact dermatitis in sensitized patients. We describe a patient with occupational asthma induced by the inhalation of samba (Triplochiton scleroxylon) wood dust. A specific bronchial provocation test was conducted, and the patient showed a significant decrease in forced-expiratory volume in first second (FEV1) after the inhalation of nebulized samba wood allergens. We suggest an IgE-mediated mechanism since the patient had a positive skin test and positive specific IgE determinations using an extract of samba wood. SDS-PAGE immunoblots revealed IgE binding to proteins with molecular weights of 17 kDa, 28 kDa and less intense binding to a band with an approximate molecular weight of 60 kDa. Two asymptomatic skin test-negative subjects, also occupationally exposed to samba, did not show any signs of bronchoconstriction when challenged with the samba wood extracts. We conclude that the occupational asthma suffered by this patient is related to sensitization and occupational exposure to samba wood dust.

Month of birth, atopic disease, and atopic sensitization

BACKGROUND

Japanese cedar (Cryptmeria japonica; CJ) pollen and house dust mites are the two important aeroallergens in Japan. However, no epidemiological survey has been performed in Japan to investigate the relationship between month of birth and manifestations of allergic disease and sensitization.

OBJECTIVE

This study evaluates the correlation between month of birth and sensitization to aeroallergens or the occurrence of allergic disease on 755 Japanese school children aged 12-13 years.

METHODS

The personal history of atopic disease (bronchial asthma, allergic rhinitis, eczema, and allergic conjunctivitis) as recorded by questionnaires was investigated in relation to total serum IgE and specific IgE toward house dust mites and CJ pollen.

RESULTS

Positive specific IgE toward house dust mites was significantly less prevalent in the children born between January and March than those born during the rest of the year (p < 0.01). Positive specific IgE toward CJ pollen was significantly more prevalent in the children born between December and January than those born during the rest of the year (p < 0.05). High total IgE was less prevalent in the children born between February and April than in children born during the rest of the year (p = 0.05). The prevalence of bronchial asthma was 26.2% among children born between November and December, compared with a ratio of 17.3% among children born during the rest of the year (p < 0.05). A significantly higher proportion of the children with allergic rhinitis was born between August and October than during the rest of the year (p < 0.05). The prevalence of allergic conjunctivitis was 15.8% among the children who were born between December and January, compared with 9.1% among children born during the rest of the year (p < 0.01). No relationship between prevalence of eczema and season of birth was found.

CONCLUSION

Month of birth appears to influence the risk in the development of allergic sensitization and atopic diseases. The findings concerning higher CJ pollen sensitization in children born in the months that proceed the CJ pollen seasons are as evident as the house-dust-mite-related findings.

The atopy patch test -- reproducibility and comparison of different evaluation methods

BACKGROUND

There is still a lack of standardization of the atopy patch test (APT) in test procedures and evaluation methods. Our aim was to examine the reproducibility of APT results and to compare visual evaluation to chromametry and laser Doppler imaging.

METHODS

Fifty-two volunteers with atopic eczema/dermatitis syndrome (AEDS) were included. The APT was performed on tape-stripped and unstripped test fields on their backs using cat dander, house dust mite and grass pollen allergens from two different suppliers. Responders were re-tested 4-12 weeks later with the same allergens on their forearms.

RESULTS

Using Allergopharma allergens, 14 (26.9%) volunteers showed one or more positive reactions. The reproducibility rate was 56.3%. The Erlangen atopy score in APT-positive and negative volunteers was 19 +/- 6 vs 15 +/- 6. The test agreement in volunteers tested with both allergens, from Allergopharma and Stallergènes, was poor. Correlation of the results between the three evaluation methods was significant (P < or = 0.001).

CONCLUSIONS

The low reproducibility rate of APT results and the poor inter-test-agreement using allergens from different suppliers show that much work remains to make the APT a reliable tool in identifying relevant aeroallergens that lead to flare ups of AEDS. Compared to chromametry and laser Doppler imaging, visual scoring was superior in differentiation between irritative and allergic reactions.

Preparation and characterization of silverfish (Lepisma saccharina) extract and identification of allergenic components

BACKGROUND

Airborne insect antigens represent important aeroallergens which have been widely investigated. Although it has been demonstrated that house dust contains significant silverfish (Lepisma saccharina) levels, none of the extracts obtained so far has been extensively characterized. Thus, we have prepared and characterized a silverfish extract and investigated its IgE-reactive components by testing the reactivity of sera from patients allergic to inhalant insect allergens.

METHODS

The extract from silverfish insect bodies was prepared by homogenizing frozen silverfish in Tris-HCl buffer. The soluble material (Sup) was filtered and the insoluble material (Ppt) was resuspended in 100 mM Tris pH 10.6. The two fractions were characterized by biochemical and immunochemical methods. IgE reactivity was investigated on both fractions before and after periodate treatment.

RESULTS

Protein content and total carbohydrates was 2 and 3% w/w for Sup and 1 and 0.3% w/w for Ppt. The SDS-PAGE profile of the two fractions showed a different pattern in the MW range of 5-175 kD. Sup and Ppt, probed with allergic sera, showed a complex pattern of IgE reactivity. When periodate-treated fractions were tested, IgE reactivity was either completely abrogated, reduced or not affected, depending on the allergic serum employed.

CONCLUSIONS

The results obtained indicate that the classic aqueous-extraction procedures that have been used up to now for other insects might not be completely satisfactory, since several allergenic components are not soluble at the normally used pH. We developed a dedicated extraction procedure allowing the detection of a certain degree of reactivity in sera negative to allergens extracted following classic procedures.

Murine strain differences in airway inflammation induced by diesel exhaust particles and house dust mite allergen

BACKGROUND

Differences in allergic airway inflammation induced by ovalbumin (OVA) + diesel exhaust particles (DEP) in various murine strains have already been reported. However, there is no report that different murine strains respond differently towards house dust mites or DEP, which are known to aggravate allergic asthma.

METHODS

The Dermatophagoides farinae allergens Der f (1 microg) or Der f (1 microg) + DEP (50 microg) were administered intratracheally to two different mouse strains (CBA/JN and C57BL/6N). Histological changes in the lung tissues, asthma-relevant cytokines in the lungs, and allergen-specific immunoglobulins in plasma were investigated.

RESULTS

Der f treatment led to the proliferation of goblet cells, production of mucus plugs, and the recruitment of eosinophils and lymphocytes to the airways of the mice. The manifestation of the airway inflammation in the C57BL/6N mouse was much greater than in the CBA/JN mouse. The protein levels of interleukin (IL)-4 and IL-5, regulated on activation, normal T cell expressed, and presumably secreted (RANTES), and eotaxin in the lung tissue of C57BL/6N mice were higher than those in CBA/JN mice by a factor of 1.26 (IL-4), 5.26 (IL-5), 2.07 (RANTES) and 3.27 (eotaxin). DEP aggravated the manifestations of the eosinophilic inflammation in CBA/JN mice through goblet cell proliferation. However, the exact effect of DEP could not be evaluated in C57BL/6N because of its severe enhancement of the inflammation. DEP enhanced the local expression of IL-5, RANTES, and eotaxin in the CBA/JN mouse, and consequently triggered an increased IgG1 production in both strains. Allergen-specific IgE antibodies were lower than 1 titer in both mice.

CONCLUSION

The murine strain differences in the pathogenesis of allergic airway disease caused by mite allergen might be related to the local expression of the cytokines we screened. The aggravating effect of DEP may be mediated by an increase in the local expression of IL-5, RANTES, eotaxin, and the production of an antigen specific to IgG1.

Level of silica in the respirable dust inhaled by dental technicians with demonstration of respirable symptoms

Dental technicians are exposed to various dusts in working laboratories. This study was conducted to measure level of silica in the respirable dust generated from dental fixed prosthodontics manufacturing processes using Fourier Transform Infrared Spectroscopy (FTIR), and to compare their occurrence of respiratory symptoms with that of non-dental hospital workers (control group). Respirable dusts were personally sampled from dental technicians working at dental laboratories in Seoul Korea according to NIOSH Method 0600. Fifty personal samples were obtained during porcelain or polishing process and weighed by a gravimetric method. Concentration of respirable dust was 651 +/- 548 microg/m3 (Mean +/- SD) with highest concentration of 2,874 microg/m3 during the porcelain process and 725 +/- 414 microg/m3 with highest concentration of 1,764 microg/m3 during the polishing process. Concentration of silica was 6.51 +/- 6.07 microg/m3 with 18.85 microg/m3 highest and 14.88 +/- 11.21 microg/m3 with 50.98 microg/m3 highest for the porcelain and polishing process, respectively. Level of silica contents in the dust was 0.81% and 1.66% for the porcelain and polishing process, respectively. The level of silica contents and silica concentration were significantly different between the two processes. Comparing prevalence of respiratory symptoms between non-smoking seventeen dental technicians and thirty-five control workers, wheezing and rhinorrhea were significantly more manifested in the dental technicians than the controls. Total frequency of respiratory symptoms was also significantly higher in the dental technicians than the controls.

Fatal asthma from powdering shark cartilage and review of fatal occupational asthma literature

BACKGROUND

Work-related asthma (WRA) is the most common work-associated respiratory disease in developed countries.

METHOD

We report shark cartilage dust as a new potential cause of occupational asthma (OA) in the context of other fatal OA case reports.

RESULTS

A 38-year-old white male worked for 8 years in a facility which primarily granulated and powdered various plastics. Sixteen months prior to his death, the plant began grinding shark cartilage. After 10 months of exposure, he reported chest symptoms at work in association with exposure to shark cartilage dust and a physician diagnosed asthma. Six months later, he complained of shortness of breath at work and died from autopsy-confirmed asthma. The latency from onset of exposure to symptoms and from symptom onset to death was shorter than 10 previously reported OA fatalities.

CONCLUSION

Recognition of occupational causes and triggers of asthma and removal of affected individuals from these exposures is critical and can prevent progression to irreversible or even fatal asthma.

Pulmonary epithelial response in the rat lung to instilled Montserrat respirable dusts and their major mineral components

BACKGROUND

The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders.

AIMS

To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz).

METHODS

Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes.

RESULTS

Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage.

CONCLUSION

Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation.

Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 2: Effects of inhaled HDS on control and heaves horses

To evaluate inhaled hay dust suspensions (HDS) as a tool for the diagnosis and investigation of heaves, the pulmonary inflammatory and functional consequences of inhalation challenge with 3 different HDS were determined in 6 control and 7 asymptomatic heaves horses. Heaves horses given HDS challenge developed the characteristic features of heaves, including airway neutrophilia, obstructive airway dysfunction and mucus hypersecretion. While HDS challenge induced a mild airway neutrophilia in controls, the no-response threshold for controls was greater than that of heaves horses, and there was no overlap in BALF neutrophil ratio of controls and heaves horses. Furthermore, HDS challenge did not induce airway dysfunction or mucus hypersecretion in controls. Therefore, HDS challenges enabled differentiation of control and heaves horses. Interestingly, in both groups, the airway neutrophilia was a dose-dependent response rather than an 'all or nothing' response. This study suggests that HDS challenges are of value in the diagnosis and investigation of heaves.

Bronchial responsiveness to eucapnic hyperventilation and methacholine following exposure to organic dust

STUDY OBJECTIVE

Inhalation of dust in a swine confinement building causes an intense airway inflammatory reaction in the airways and increased bronchial responsiveness to methacholine. The aims of the present study were to investigate whether exposure to organic dust also influences bronchial responsiveness to an indirect stimulus, and to assess the duration of increased postexposure bronchial responsiveness.

DESIGN

Twenty-two healthy nonatopic, nonsmoking subjects were exposed to dust for 3 h in a swine confinement building. Lung function was assessed, and either a methacholine bronchial provocation (n = 11) or a challenge with eucapnic hyperventilation of dry air (n = 11) was performed before exposure and at 7 h, 1 week, 2 weeks, and 4 weeks after exposure.

RESULTS

Vital capacity and FEV(1) decreased 3% and 6%, respectively (p < 0.001), and airway resistance increased 15% (p < 0.05) after exposure. The median provocative dose of methacholine causing a 20% decline in FEV(1) fell from 1.38 mg (25th to 75th percentiles, 0.75 to 7.20 mg) before exposure to 0.18 mg (0.11 to 0.30 mg) after exposure (p = 0.004). Corresponding values for the dose-response slope were 15.3%/mg (2.88 to 25.3%/mg) and 100.2%/mg (2.1 to 27.3%/mg), respectively (p = 0.01). Bronchial responsiveness to eucapnic hyperventilation was not affected by the exposure: FEV(1) fell 4.3% (- 7.2 to - 1.8%) before and 4.8% (- 6.7 to - 1.6%) after exposure (p = 0.72). One week after exposure, the bronchial responsiveness to methacholine was normalized.

CONCLUSIONS

The bronchial responsiveness to methacholine but not to dry air increases after exposure to swine house dust. Thus, exposure to organic dust induces increased bronchial responsiveness with different characteristics from that frequently found in asthma.

Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 3: Effect of fractionation of HDS

To investigate the relative importance of inhaled particulates and soluble components in the response to inhaled hay dust suspension (HDS), heaves (previously termed chronic obstructive pulmonary disease; n = 7) and control (n = 6) horses were given inhalation challenges with whole and fractionated HDS. Fractionation was achieved by centrifugation to yield supernatant (SUP) and particulate debris. The particulates were then washed repeatedly in saline to produce a washed particulate (WP) fraction which comprised mainly fungal spores, and a wash fraction (WF) which comprised saline and soluble components washed from the surface of the particulates. Inhalation of HDS and SUP induced a significant airway neutrophilia in both groups, with the magnitude of the response being significantly greater in heaves horses. SUP induced significantly less airway neutrophilia than HDS in both groups, despite the endotoxin and protease content of HDS and SUP being comparable. WP and WF induced only a slight airway neutrophilia in heaves horses. However, a combined challenge with SUP and WP induced a neutrophilic response approaching the magnitude of that following HDS challenge, indicating that dust particulates contribute to the pulmonary recruitment of neutrophils in heaves. Consequently, inhalation challenge with HDS, which contains both particulates and soluble dust components, may be a more useful tool for the diagnosis and investigation of heaves than aqueous dust extracts, which contain only soluble components.

Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 1: Preparation and composition of HDS

Currently, heaves is investigated by exposing susceptible horses to dusty hay. Consequently, the response will be dependent on the organic dust content and composition of the hay. It was hypothesised that the use of a hay dust suspension (HDS) would reduce the variability of the challenge and therefore standardise experimental protocols. Furthermore, analysis of HDS would also permit further investigation of the organic dust components responsible for the response. Three hay dust suspensions (HDS-1, 2 and 3) were prepared for use in the diagnosis and investigation of heaves. HDS were produced from fine dust particles, comprising mostly fungal spores, collected from 3 batches of dusty hay. HDS-1 and 3 were analysed for endotoxin, beta-D-glucan and protein concentrations, general protease activity and enumeration and size distribution of particulates. Protease activity was mainly attributable to a 28 kDa serine protease and to 85 kDa and 160 kDa metalloproteases. The particulate and soluble components of HDS could be aerosolised by jet nebulisation. We therefore conclude that detailed analysis of HDS is possible, that such a challenge system provides a method of standardising experimental protocols and that all components of HDS (both soluble and particulate) can be delivered to the lung using standard nebulisation techniques. For the above reasons, nebulised HDS offers considerable advantages over conventional hay/straw challenge for the diagnosis and investigation of heaves.

[Dust exposure and cancer risk associated with amphibolite mining and processing]

Mining and processing of amphibolite is associated with workers' exposure to dust containing asbestos minerals (actinolite, tremolite) and with the presence of respirable fibers, i.e. small particles above 5 microns long and below 3 microns in diameter (with length-to-diameter ratio higher than 3:1). Results of epidemiological and laboratory studies show that such dust may be responsible for the development of cancer in dust-exposed people. This work reports the measurement results of concentrations of total dust, respirable fibers and mineral composition of samples collected in plant mining and processing amphibolite rock. Based on the results, cumulated exposure was calculated for the 10-, 20- and 30-year exposure periods. The cumulated exposure was classified into two categories: 0.1-1.0 f/cm3 years and 1.0-10 f/cm3. x years. It has been found that mining and processing of amphibolite is associated with increased risk of death from mesothelioma--11.2 x 10(-5) (crushers--10 years of exposure) to 240.0 x 10(-5) (miners--30 years of exposure). The risk of excessive mortality from lung cancer was not high (below 1. x 10(-4)) for all workplaces and periods of exposure.

Evaluation of airborne dust and endotoxin in corn storage and processing facilities in Colorado

The main objectives of this research were to determine what aerosols were present by taking total dust (TD) samples and thoracic particulate mass samples (TPM) on farms and in grain elevators. Cascade impactors were used to characterize size distributions of dust and endotoxins at each site. Total dust concentrations on farms had a geometric mean 3.4 mg/m3 and 3.3 mg/m3 in elevators. The geometric mean (GM) concentrations for the TPM were 2.4 mg/m3 on farms and 1.0 mg/m3 in elevators. Endotoxin concentrations as geometric means were alarming at 3175 EU/m3 total dust and 983 EU/m3 by TPM on farms. In elevators, the GM concentrations for endotoxins were 2534 EU/m3 total dust, and 526 EU/m3 by TPM. The mass median aerodynamic diameter (MMAD) for endotoxins on farms was 8.0 microm and 6.5 microm in elevators. The paired t-test was applied to the log ratios of endotoxin concentrations (EU/m3) and dust concentrations (mg/m3), for paired samples of the TD and TPM. A higher content of endotoxins was associated with TPM for farms but not elevators. It was concluded that although the TPM fraction (dust) may represent a small part of the total mass, the aerosol size is optimum for deposition in the lung's tubular airways, and might cause airway inflammation due to the endotoxins. The TPM fraction of corn dust represents the best measure of exposure with regard to the potential development of long-term airways inflammation, and the potential of chronic obstructive pulmonary disease among chronically exposed workers. All endotoxin concentrations were well above recommended exposure levels of several researchers familiar with endotoxin health effects.

Broncho-alveolar inflammation in cork worker's asthma

Suberosis is an occupational lung disease of cork workers associated with repeated exposure to mouldy cork dust in the cork industry, usually presenting as an interstitial lung disorder (Extrinsic Allergic Alveolitis). However, Occupational Asthma can also be associated with cork dust exposure and demonstrated by serial peak expiratory flow changes.

AIM

To investigate broncho-alveolar inflammation in patients with cork work-related occupational asthma, evaluated by Broncho-alveolar fluid cellular profiles and serial peak expiratory flow (PEF) rates monitoring.

RESULTS

We studied 14 patients with respiratory symptoms associated with occupational exposure in the cork industry. Positive PEF monitoring occurred in 7 cases (Occupational Asthma-OA), and in 7 (Non-occupational asthmatics-NOA) PEF records were negative. There were no differences in age, lung function (FEV1%, RV%), bronchial hyperresponsiveness, years of exposure, and atopy between the two patients groups. However, patients with work-related asthma had higher BAL eosinophil counts than NOA (1.9 +/- 2.6% versus 0.2 +/- 0.3%; p < 0.05, Wilcoxon test).

CONCLUSIONS

Cork worker's asthma, demonstrated by work related changes in serial PEF recordings, is associated with eosinophilic lung inflammation as described in other forms of occupational asthma.

Feather bedding and house dust mite sensitization and airway disease in childhood

Feather bedding has been inversely associated with child wheeze and also with house dust mite (HDM) allergen levels. We conducted a cross-sectional analysis of the childhood component of a birth cohort study. Our aim was to examine the relation between feather bedding and HDM sensitization and airway disease. A total of 498 children (84% of eligible) residing in Northern Tasmania in 1997 who were eligible for the Tasmanian Infant Health Survey at birth in 1988 or 1989 participated. Outcome measures included atopic sensitization to Dermatophagoides farinae or Dermatophagoides pteronyssinus allergens, spirometric lung function, and child respiratory symptoms using questions from the ISAAC study. HDM sensitization was strongly associated with frequent wheeze (more than 12 episodes of wheeze compared with no wheeze in the past year) (rate ratio [RR], 19.61; confidence interval [CI], 6.94-55.56) but only weakly associated with asthma ever (RR, 1.65; CI, 1.30-2.09). Feather quilt use was associated with reduced HDM sensitization (adjusted RR [ARR], 0.60; CI, 0.45-0.80) and also reduced frequent wheeze episodes over the past year (ARR, 0.24; CI, 0.07-0.86). The reduction in wheeze was more evident among HDM-sensitized children. These findings are consistent with the possible mechanisms for feather bedding of a reduction in initial HDM sensitization and an improvement in respiratory symptoms among HDM-sensitized children. However, prospective studies are required to fully exclude selection bias.

[On mechanisms underlying bronchial obstruction in chronic dust bronchitis in workers of deep coal mines]

Healthy miners demonstrated increased relative levels of lysophosphatidyl choline and especially phosphatidyl inositol subunits. Metabolism of the latter could result in membrane accumulation of inositol triphosphate leading to cytoplasmic calcium increase and to bronchial smooth muscles contraction. Oral 20% choline chloride solution lowers bronchospasm in dust bronchitis patients with decreased serum subunits of phosphatidyl inositol and increased serum levels of phosphatidyl choline.

Dust emission and efficiency of local exhaust ventilation during cast iron grinding

A method of determining dust emission and efficiency of its removal by means of local exhaust ventilation from machinery has been described. It complies with Standard No. EN 1093-3:1996 (European Committee for Standardization, 1996) and consists in determining air pollution concentrations in the measurement duct used for air removal from the chamber incorporating devices to be tested. The air volume stream that is pumped is measured at the same time. Test results are presented for dust emission and the efficiency of local exhaust ventilation for cast iron grinding by means of manual power tools and a bench-sander. It has been found that application of local exhaust ventilation contributes to a significant reduction of dust emission with efficiency greater than 90%.

In vitro bioavailability of heavy metals in pressure-treated wood dust

Pressure treatment with chromium, copper, and arsenic (CCA) is the most prevalent method for protecting wood used in outdoor construction projects. Although these metals are tightly bound to the wood fibers and are not released under most conditions of use, we examined the bioavailability of metals in CCA pressure-treated wood dust in vitro. Cytotoxicity and metallothionein (MT) mRNA expression were examined in V79 Chinese hamster lung fibroblast cells incubated with respirable-size wood dust generated by sanding CCA-treated and untreated (control) Southern yellow pine. In colony survival studies, increased cytotoxicity (p < 0.05) occurred in V79 cells treated with CCA wood dust (351 +/- 77 microg/ml, mean +/- SE) compared with control wood dust (883 +/- 91 microg/ml). Increased cytotoxicity with CCA wood dust also occurred in an arsenic resistant subline of V79 cells, thus suggesting that arsenic was not responsible for the increased cytotoxicity. Metallothionein mRNA was significantly increased after 48 h of treatment with CCA wood dust compared with control wood dust. Incubation of CCA wood dust in cell culture media resulted in the transfer of copper, but not chromium or arsenic, into the media. Moreover, the treatment of cells with this filtered extract resulted in significantly increased metallothionein mRNA, suggesting that bioavailable copper is responsible for inducing metallothionein mRNA in V79 cells. Thus, these bioassays suggest that metals become bioavailable during in vitro culture of phagocytic V79 cells with CCA wood dust.

Lead awareness: North Philly Style

Lead poisoning in children has been associated with reduced intelligence, shortened memory, slowed reaction times, poor hand-eye coordination, and antisocial behavior. The cost to society includes not only medical treatment and special education but also higher high-school drop-out rates, which are associated with crime and low earning potential.

Coal dust exposures in the longwall mines of New South Wales, Australia: a respiratory risk assessment

This paper presents an analysis of personal respirable coal dust measurements recorded by the Joint Coal Board in the underground longwall mines of New South Wales from 1985 to 1999. A description of the longwall mining process is given. In the study, 11 829 measurements from 33 mines were analysed and the results given for each occupation, for seven occupational groups, for individual de-identified mines and for each year of study. The mean respirable coal dust concentration for all jobs was 1.51 mg/m(3) (SD 1.08 mg/m(3)). Only 6.9% of the measurements exceeded the Australian exposure standard of 3 mg/m(3). Published exposure-response relationships were used to predict the prevalence of progressive massive fibrosis and the mean loss of FEV(1), after a working lifetime (40 years) of exposure to the mean observed concentration of 1.5 mg/m(3). Prevalences of 1.3 and 2.9% were predicted, based on data from the UK and the USA, respectively. The mean loss of FEV(1) was estimated to be 73.7 ml.

Respiratory symptoms, lung function, and nasal cellularity in Indonesian wood workers: a dose-response analysis

OBJECTIVES

It was hypothesised that inflammation plays a dominant part in the respiratory effects of exposure to wood dust. The purpose of this study was to relate the nasal inflammatory responses of workers exposed to meranti wood dust to (a) levels of exposure, (b) respiratory symptoms and (c) respiratory function.

METHODS

A cross sectional study was carried out in 1997 in a woodworking plant that used mainly meranti, among 982 workers exposed to different concentrations of wood dust. Personal sampling (n=243) of inhalable dust measurements indicated mean exposure in specific jobs, and enabled classification of 930 workers in three exposure classes (<2, 2-5, and >5 mg/m(3)) based on job title. Questionnaires were used to screen respiratory symptoms in the entire population. Lung function was measured with two different techniques, conventional flow-volume curves and the forced oscillation technique. Nasal lavage was done to assess inflammation in the upper respiratory tract.

RESULTS

A negative trend between years of employment and most flow-volume variables was found in men, but not in women workers. Current exposure, however, was not related to spirometric outcomes, respiratory symptoms, or nasal cellularity. Some impedance variables were related to current exposure but also with better function at higher exposure.

CONCLUSIONS

Exposure to meranti wood dust did not cause an inflammation in the upper respiratory tract nor an increase of respiratory symptoms or decrease of lung function. These data do not corroborate the hypothesis that inflammation plays a part in airway obstruction induced by wood dust.

[A case of occupational asthma caused by Ayous wood (Triplochiton scleroxylon)]

A 58-year-old man, a carpenter, had been suffering from cough, rhinorrhea, wheezing, dyspnea and ocular itching a few minutes after each exposure to the sawdust of "Ayous" wood (Obeche, Triplochiton scleroxylon) since starting to work on this imported wood in 1998. Although his symptoms improved soon after exposure, he had a secondary response several hours later. He had no symptoms when working with any other woods. In January, 2001, he came to our hospital, and occupational asthma was suspected. Peak flow monitoring revealed immediate- and late-type responses when he was exposed to Ayous wood dust. Non-specific bronchial hyperresponsiveness to acetylcholine was positive. An immediate skin test with Ayous wood extract was positive. In the RAST inhibition test, his serum revealed specific IgE antibody to Ayous extract. Bronchoprovocation with Ayous wood extract demonstrated immediate and later type responses (dual response). Occupational asthma caused by Ayous wood dust was confirmed. This is the first case report of occupational asthma caused by Ayous wood in Japan.