Synthesis and aqueous phase behavior of 1-glyceryl monooleyl ether

Synthesis of 1-glyceryl monooleyl ether (GME) has been accomplished yielding material of high purity (99.6%). The aqueous phase behavior of synthesized lipid has been investigated by using polarized microscopy and small angle X-ray diffraction. As a result, a partial temperature-composition phase diagram has been constructed. GME forms a reversed micellar solution and reversed hexagonal liquid crystalline phase at low and high hydration, respectively. The hexagonal phase coexists with excess water and is stable up to about 63 degrees C. These findings make GME an interesting alternative to glycerol monoesters in various fields of applications.

Genomic and functional delineation of dendritic cells and memory T cells derived from grass pollen-allergic patients and healthy individuals

Dendritic cells (DCIs) possess a potent ability to modulate and activate specific T-cell responses to allergens, which play a pivotal role in allergic inflammation by secreting cytokines and other mediators. However, the molecular mechanisms by which allergen-challenged DCs regulate specific T-cell responses are still not well characterized. This study aims at elucidating the molecular mechanisms underlying the DC-T-cell interaction during an allergic immune response to grass pollen, using a genomic and functional approach. Transcriptional analysis was performed on grass allergen Phleum pratense-stimulated DCs and on autologous memory CD4(+) T cells co-cultured with allergen-challenged DCs from healthy and allergic donors. DCs from the allergic donors were potent inducers of T-cell proliferation and T(h)2 polarization, as demonstrated by high IL-4, IL-5 and IL-13, and low IFN-gamma production. A gradual up-regulation of activation markers on both DCs and T cells was evident during the co-culture period, demonstrating an educational element of the DC-T-cell interaction. The global transcriptional analysis revealed a differential gene regulation in DCs and T cells derived from allergic donors after stimulation with allergen, as compared with the healthy donors. Peripheral memory CD4(+) T cells from healthy and allergic donors also responded differently after stimulation with allergen-loaded DCs with respect to cytokine production, proliferation, surface marker expression and gene transcription. We found up-regulated genes involved in T(h)2 cell biology, such as genes important for homing, adhesion, signaling and transcription, in addition to genes previously not described in the context of allergy. The panel of differentially expressed genes in the allergic group will form the basis for an increased understanding of the molecular mechanisms in allergy.

Dementia and depressive symptoms as predictors of home help utilization among the oldest old: population-based study in an urban area of Sweden

OBJECTIVE

The objective of this article is to investigate predictors of public home help utilization, particularly mental health problems such as dementia and depressive symptoms.

METHODS

A population-based sample of community-dwelling people aged 81-100 was interviewed and assessed with medical examinations (N = 502).

RESULTS

Dementia increased the odds of receiving public home help among people residing alone. Among coresiding people, it increased the odds of receiving home help, but only among those who had extra residential care. Depressive symptoms decreased the odds of receiving home help among people with lower levels of education who lived alone. Depressive symptoms among highly educated people who lived alone and among coresiding people of any educational level were not related to receipt of home help.

DISCUSSION

Improvement of screening activities for public home help needs of community-dwelling elders might allow better targeting of limited social resources to the most needy.

The effect of fluticasone on the airway inflammatory response to organic dust

Exposure to organic dust in a swine house causes acute airway inflammation and increased bronchial responsiveness to methacholine in healthy subjects. The aim of this study was to investigate whether an inhaled glucocorticoid, fluticasone propionate, alters the acute airway responses induced by exposure in a swine barn. In 15 healthy subjects, analysis of nasal lavage fluids, serum samples and bronchial methacholine responsiveness were performed before and after exposure to organic dust in a swine house for 3 h. Seven subjects received fluticasone propionate (500 microg b.i.d. by inhalation and 100 microg intranasally once daily) and eight subjects received placebo during the 2 weeks prior to exposure. Post-exposure plasma interleukin (IL)-6 levels and body temperature were significantly lower in the fluticasone group than in the placebo group. Intranasally administered fluticasone propionate significantly attenuated the plasma protein (assessed as albumin concentrations) leakage and IL-8 and tumour necrosis factor-alpha response induced by exposure. Fluticasone propionate inhalation exerted no influence on the increased bronchial responsiveness to methacholine induced by exposure. In conclusion, glucocorticoid treatment attenuated the inflammatory response to inhaled organic dust without influencing the increased bronchial responsiveness to methacholine.

Allergen avoidance does not alter airborne cat allergen levels in classrooms

BACKGROUND

Some schools in Sweden offer allergen avoidance classrooms for allergic children with severe asthma. However, the measures commonly used to achieve a reduction in allergen levels have not been properly evaluated. The aim of the present prospective study was to study whether the levels of airborne cat allergen are altered after introducing feasible intervention measures in classrooms, without interfering with peoples' freedom of choice regarding pet ownership.

METHODS

Twenty-five classes, including five established allergy prevention classrooms participated in the study during a school year. After one term, six classes underwent a number of intervention measures recommended by the Swedish National Institute of Public Health. Curtains, upholstery and plants were removed, bookshelves were replaced with cupboards and regular cleaning was increased. Airborne dust was collected weekly (32 weeks) using duplicate Petri dishes (n = 1574) and on six occasions using two personal air samplers in each class (n = 264).

RESULTS

Airborne cat allergen levels were showing a similar variability throughout the whole study in all classes. Despite extensive measures in order to reduce allergen exposure, cat allergen levels were unaltered in the six classes after intervention. Allergen levels were not significantly lower in the established allergy prevention classes, compared with the other classes. Cat allergen levels differed, however, significantly between classes with few and many cat owners (P < 0.05).

CONCLUSIONS

We conclude that the recommended allergen avoidance measures used in this study did not reduce airborne cat allergen. It seems plausible that measures that fail to reduce allergen levels also fail to influence health status in allergic children but this remains to be shown.

Impaired temperature regulation in rats after anosmia induced peripherally or centrally

Bilateral olfactory bulbectomy or destruction of the olfactory epithelium of rats resulted in elevated body temperature in room temperature, and lowered water/food ratio in 30 degrees ambient temperature. The results suggest the involvement of the olfactory system in the thermoregulation.

Allergic sensitization among adults in Tallinn, Estonia

BACKGROUND

The prevalence of allergic sensitization has increased worldwide during recent years.

OBJECTIVE

The aim of the study was to estimate the prevalence of allergic sensitization and to evaluate the influence of age, gender, number of siblings, pet keeping in childhood, and residential area before the age of five on allergic sensitization among adolescents and adults aged 17-66 years in the capital of Estonia, Tallinn. A cross-sectional study was carried out between March 1997 and December 1998.

METHODS

The sensitization to 15 inhalant allergens was assessed. The associations between sensitization based on skin prick tests (SPTs), symptoms based on a structured interview, and possible risk factors were estimated. A random sample of 516 subjects was included in the study analysis.

RESULTS

The prevalence of allergic sensitization was 34.5%, while it was 39.3% in subjects aged 20-44 years. The most prevalent sensitization was against the German cockroach, 15.5%, and it was particularly high among adolescents. It was followed by mugwort, dog, two storage mites species, and cat dander. Subjects with wheezing during the last 12 months, attacks of shortness of breath, wheezing due to furred animals, and allergic rhinitis or conjunctivitis had a significantly higher prevalence of positive SPT.

CONCLUSION

We found a surprisingly high prevalence of allergic sensitization among adults in Tallinn. Our results suggest that the cockroach allergen should be included in the investigation panel in order to reach a true prevalence of allergic sensitization in Estonia. Further, the pattern of allergic sensitization in Estonia appears to be different from published data about allergic sensitization in Scandinavia.

Ischaemic heart disease among livestock and agricultural workers

BACKGROUND

Agricultural workers are exposed to organic dust containing endotoxins, mites, and moulds.

AIMS

To compare the occurrence of ischaemic heart disease (IHD) among male and female livestock and agricultural workers with gainfully employed men and women in Sweden.

METHODS

Male and female livestock and agricultural workers were identified in the Swedish National Censuses of 1970 and 1990 and were followed until the end of 1995. The IHD mortality among the livestock and agricultural workers was compared with that of gainfully employed men and women. Information of smoking habits was gathered from a previous national survey.

RESULTS

Male as well as female livestock workers had slightly higher standardised mortality ratios (SMR) regarding IHD compared with all gainfully employed men and women in Sweden. The SMR for male workers was 1.06 (95% CI 0.95 to 1.18). The SMR for female workers was 1.10 (95% CI 0.98 to 1.23). Agricultural workers had lower SMRs. Adjustments for smoking habits would further increase the SMRs by about 9% in male workers and about 5% in female workers.

CONCLUSION

The present data suggest a slightly increased risk for IHD among both male and female livestock workers, which may be the result of organic dust exposure.

A group-based patient education programme for high-anxiety patients with Crohn disease or ulcerative colitis

BACKGROUND

The inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn disease (CD) affect a person's health-related quality of life (HRQOL). IBD patients report high levels of anxiety, which correlates with the degree of perceived dissatisfaction with the information on disease-related themes provided in routine health care. The aim of this study was to evaluate changes in anxiety after participation in a group-based educational intervention for IBD patients screened for high anxiety.

METHODS

The programme consisted of 8 sessions, and 49 patients participated. Anxiety was assessed using the Hospital Anxiety and Depression (HAD) Scale at baseline and 6 months after intervention. HRQOL was assessed with the Inflammatory Bowel Disease Questionnaire (IBDQ) and the SF-36 health survey. Participant satisfaction with education was measured using a study-specific questionnaire.

RESULTS

No significant change on the HAD anxiety score was found at the 6-month follow-up for those who participated in the education programme despite the fact that the participants reported they had gained better knowledge of disease-related items. Furthermore, there were no significant changes over time regarding bowel symptoms, systemic symptoms, emotional functioning and social functioning of the IBDQ or generic HRQOL (SF-36).

CONCLUSIONS

IBD patients with a high anxiety level reported improved satisfaction with information about disease-related items, but did not indicate any benefits in terms of reduced anxiety or improved HRQOL after participating in the education programme, not at least in the short-term perspective. In this selected group of patients, psychosocial problems other than disease-related concerns were found that warrant other approaches.

Passive smoking and respiratory symptoms in the FinEsS Study

The aim of the present study was to examine the relationship between reported environmental tobacco smoke (ETS) exposure and respiratory symptoms. In 1996, a postal questionnaire was randomly distributed in three areas of Estonia to a population-based sample, of which 4,995 females and 1,822 males had never smoked. The main outcome measures were current respiratory symptoms and the amount of reported ETS exposure outside the home. ETS exposure at home was more common in females (31% versus 19%), while exposure outside of the home was more common in males (53% versus 7%). Females reported more symptoms from tobacco smoke than males (37.7% versus 21.6%). If ETS exposure outside of the home exceeded 5 h daily, the risk for wheeze (odds ratio (OR) 2.67, 95% confidence interval (CI) 1.98-3.61) and physician-diagnosed asthma (OR 1.79, 1.02-3.16) were increased. ETS exposure outside of the home was shown to be strongly related to almost all respiratory symptoms in a dose/response manner. ETS exposure at home did not show significantly elevated ORs for any respiratory symptoms. This study shows that females seem to be more troubled by environmental smoke exposure than males and provides further evidence of the serious health hazards associated with environmental smoke exposure. Indeed, the findings of this study support a ban on smoking in the workplace and public areas.

Not 15 but 50% of smokers develop COPD?--Report from the Obstructive Lung Disease in Northern Sweden Studies

BACKGROUND

The prevalence of chronic obstructive pulmonary disease (COPD) according to guidelines of today seems considerably higher than has been reported also in recent literature.

AIM

To estimate the prevalence of COPD as defined by British Thoracic Society (BTS) criteria and the recent global initiative for chronic obstructive lung disease (GOLD) criteria. Further aims were to assess the proportion of underdiagnosis and of symptoms in subjects with COPD, and to study risk factors for COPD.

METHODS

In 1996, 5892 of the Obstructive Lung Disease in Northern Sweden (OLIN) Study's first cohort could be traced to a third follow-up survey, and 5189 completed responses (88%) were received corresponding to 79% of the original cohort from December 1985. Of the responders, a random sample of 1500 subjects were invited to a structured interview and a lung function test, and 1237 of the invited completed a lung function test with acceptable quality.

RESULTS

In ages >45 years, the prevalence of COPD according to the BTS guidelines was 8%, while it was 14% according to the GOLD criteria. The absolutely dominating risk factors were increasing age and smoking, and approximately a half of elderly smokers fulfilled the criteria for COPD according to both the BTS and the GOLD criteria. Family history of obstructive airway disease was also a risk factor, while gender was not. Of those fulfilling the BTS criteria for COPD, 94% were symptomatics, 69% had chronic productive cough, but only 31% had prior to the study been diagnosed as having either chronic bronchitis, emphysema, or COPD. The corresponding figures for COPD according GOLD were 88, 51, and 18%.

CONCLUSIONS

In ages >45 years, the prevalence of COPD according to the BTS guidelines was 8%, and it was 14% according to the GOLD criteria. Fifty percent of elderly smokers had developed COPD. The large majority of subjects having COPD were symptomatic, while the proportion of those diagnosed as having COPD or similar diagnoses was small.

Effects by 8-bromo-cyclicAMP on basal and organic dust-induced release of interleukin-6 and interleukin-8 in A549 human airway epithelial cells

Inhalation of organic dust from a swine-confinement building leads to an intense inflammatory reaction with an increased number of inflammatory cells and mediators in the upper and lower respiratory tract of previously unexposed subjects. In vitro the dust induces cytokine release from epithelial cells and alveolar macrophages. It is known that intracellular cyclic AMP (cAMP) contributes to the regulation of inflammatory responses. We therefore investigated whether 8-Bromo-cAMP, a cell membrane-permeable cAMP analogue, would influence release of the cytokines interleukin-6 (IL-6) and IL-8 in a human airway epithelial cell line, A549, exposed to a suspension of the organic dust, and to a supernatant prepared by centrifugation (at low g-force) of a suspension of dust. The large particulate matter was thus sedimented, leaving bacteria, whole and cell wall constituents in the supernatant. Cytokine release was measured with enzyme-linked immunosorbent assay (ELISA). The cytokine release induced by a supernatant was 23% (IL-6) and 27% (IL-8) of the release induced by a dust suspension. 8-Bromo-cAMP (1 mM) doubled basal IL-6 release and IL-6 release induced by a dust supernatant (P<0.01), and increased IL-6 release induced by a dust suspension by 19% (P<0.05). 8-Bromo-cAMP did not affect basal IL-8 release, partially inhibited (28%) the release of IL-8 induced by a dust suspension (P<0.01), but increased IL-8 release induced by a dust supernatant by 13% (P<0.05). In summary, expression of the cytokines IL-6 and IL-8 is differentially regulated by 8-Bromo-cAMP, both with regard to basal and dust-induced release. The results indicate that 8-Bromo-cAMP attenuated IL-8 release by affecting signaling transductions induced by the particulate fraction.

Comparison of four allergen-sampling methods in conventional and allergy prevention classrooms

BACKGROUND

Several allergen-sampling methods are used to assess level of personal or indirect exposure to cat in homes, schools and other public buildings and working environments.

OBJECTIVE

To compare four different allergen-sampling methods (dust collectors, Petri dishes, person-carried pumps and intranasal samplers) by simultaneous sampling in classrooms and to compare the cat allergen levels between conventional classrooms and allergy prevention classrooms. Another aim was to relate the results to self-reported frequency of allergy and asthma symptoms among the children, to their perception of the school environment.

METHODS

Among all compulsory schools (n = 257) in the Stockholm suburban area, 35 classrooms (five with implemented allergy prevention measures, seven with additional cleaning and 23 with normal cleaning routines) were chosen for allergen-sampling. Dust collectors (two models), Petri dishes, person-carried pumps and intranasal samplers were used simultaneously. All children (n = 829) received a self-administered questionnaire which included questions about home and school environment, allergic disease, asthma symptoms and pet contact.

RESULTS

The correlation between sampling methods was generally poor.Furthermore, there was no significant difference in allergen levels between allergy prevention and allergen avoidance classes compared to conventional classes. Median levels were generally, but not significantly, lower in classes with few cat owners, compared to classes with many cat owners. Children in allergy prevention classes were more satisfied with the indoor air quality and cleaning than children attending classes with fewer or no allergy prevention measures (P < 0.0001). Nine per cent of all children reported allergic symptoms while at school.

CONCLUSION

The lack of correlation between sampling methods used simultaneously demonstrates the difficulty in assessing allergen levels in schools and similar environments. The implemented intervention measures (allergy prevention/allergen avoidance) did not influence cat allergen levels at school.

Effects of formoterol and ipratropium bromide in COPD: a 3-month placebo-controlled study

The aim of this study was to compare the effects of formoterol, ipratropium bromide and a placebo on walking distance, lung function, symptoms and quality of life (QoL) in chronic obstructive pulmonary disease (COPD) patients. A total of 183 patients (mean age 64 yrs, 86 female) with moderate-to-severe nonreversible COPD participated in this randomised, double-blind, parallel-group study. After a 2-week placebo run-in, patients were randomised to formoterol Turbuhaler 18 microg b.i.d. (delivered dose), ipratropium bromide 80 microg t.i.d. via a pressurised metered dose inhaler, or placebo for 12 weeks. Inhaled short-acting beta2-agonists were allowed as relief medication and inhaled glucocorticosteroids were allowed at a constant dose. The primary variable was walking distance in the shuttle walking test (SWT). Baseline mean SWT distance was 325 m, mean forced expiratory volume in one second (FEV1) was 40% predicted. Clinically significant improvements in SWT (>30 m) were seen in 41, 38 and 30% of formoterol, ipratropium and placebo patients, respectively (not significant). Mean increases from run-in were 19, 17 and 5 m in the formoterol, ipratropium and placebo groups, respectively. Both active treatments significantly improved FEV1, forced vital capacity, peak expiratory flow and daytime dyspnoea score compared with placebo. Formoterol reduced relief medication use compared with placebo. Neither active treatment improved QoL. Formoterol and ipratropium improved airway function and symptoms, without significant improvements in the shuttle walking test.

Prevalence and risk factors for asthma and chronic bronchitis in the capitals Helsinki, Stockholm, and Tallinn

The aim of this part of the FinEsS-studies was to assess whether differences existed in prevalence of asthma, chronic bronchitis, and respiratory symptoms between three Baltic capitals, and to examine risk factor profiles for respiratory conditions. In 1996, a postal survey was performed in these cities with a response rate of 72% in Stockholm, 76% in Helsinki, and 68% in Tallinn. The prevalence of physician-diagnosed asthma was 76% in Stockholm, 6.2% in Helsinki, and 2.3% in Tallinn, while respiratory symptoms were most common in Tallinn. The prevalence of physician-diagnosed chronic bronchitis was 10.6% in Tallinn, 3.4% in Helsinki, and 3.0% in Stockholm. Risk factor analyses revealed a significantly increased risk for those living in Tallinn compared to that of Stockholm for wheezing conditions, OR 1.56-1.69, longstanding cough, OR 1.92 (1.74-2.13), attacks of shortness of breath during the previous 12 months, OR 1.35 (1.20-1.52), and chronic productive cough, OR 1.49 (1.28-1.74). Subjects having symptoms common in asthma were more likely to have physician-diagnosed asthma in Stockholm and Helsinki than in Tallinn, while subjects having bronchitis symptoms had more often physician-diagnosed chronic bronchitis in Tallinn. Prevalence of respiratory symptoms was higher in Tallinn than in Stockholm and Helsinki, while physician-diagnosed asthma was more common in Stockholm and Helsinki. The prevalence of physician-diagnosed chronic bronchitis was three times as high in Tallinn as in Helsinki or Stockholm. Our results also suggest large differences in diagnostic practices between the three countries, while the differences between the capitals in true prevalence of disease may be small.

Sodium nitroprusside-induced rat fundus relaxation is ryanodine-sensitive and involves L-type Ca2+ channel and small conductance Ca(2+)-sensitive K+ channel components

1 The aim of this study was to examine whether sodium nitroprusside (SNP)-induced relaxation of rat fundus longitudinal smooth muscle involves ryanodine-sensitive Ca2+ release. 2 SNP (300 nM-30 microM) elicited concentration-dependent relaxation of precontracted (1 microM carbachol) rat fundus, an effect almost abolished by the selective guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, 10 microM). 3 SNP-mediated relaxations were almost abolished by 10 microM ryanodine. 4 SNP-mediated relaxations were also reduced by either 1 microM apamin (a selective small conductance Ca(2+)-sensitive K+ channel, SKCa, inhibitor) or the selective L-type Ca2+ channel inhibitor, nicardipine (3 microM). 5 SNP-induced relaxations were insensitive to 1 mM tetraethylammonium chloride (an inhibitor of large-conductance Ca(2+)-sensitive K+ channels) and 1 microM glibenclamide (an ATP-sensitive K+ channel inhibitor). 6 These data suggest that SNP-mediated fundus relaxation occurs via a cGMP-mediated and ryanodine-sensitive mechanism which requires, at least in part, SKCa and L-type Ca2+ channel activity.

Human herpesvirus 6 infection and cytomegalovirus-specific lymphoproliferative responses in allogeneic stem cell transplant recipients

The aim of this study was to investigate the effects of HHV-6 DNAemia on the CMV specific lymphoproliferative response after allogeneic stem cell transplantation. Twenty-one allogeneic stem cell transplantation (allo-SCT) patients were included in the study. The patients were either CMV seropositive and/or had CMV seropositive donors. We studied the effects of HHV-6 infection, documented by PCR, on CMV-specific lymphocyte proliferation response and on CMV infection documented by PCR. HHV-6 DNAemia correlated with the absence of CMV-specific lymphocyte proliferation responses after allo-SCT. Three of nine patients with persistent HHV-6 DNA had a CMV-specific lymphocyte proliferative response compared to 11 of 12 patients without persistent HHV-6 DNAemia (P = 0.02). Patients with higher HHV-6 DNA levels (>100 copies) were more likely than those with lower copy numbers not to develop a CMV-specific immune response (six of nine vs one of eight; P < 0.05). Patients who were repeatedly HHV-6 positive in three or more consecutive blood samples were also more likely to need repeated courses of preemptive antiviral therapy against CMV during the first 6 months after transplantation (P < 0.001). Our data indicate the possibility that HHV-6 can suppress the development of CMV-specific immune responses and thereby could predispose to development of late CMV disease.

Organic dust-induced interleukin-12 production activates T- and natural killer cells

Exposure in swine confinement buildings causes intense airway inflammation and lymphocyte activation, as assessed by bronchoalveolar lavage. To further clarify the T-cell activation, the present in vitro study focused on intracellular cytokine production following exposure to organic dust from swine houses. Whole blood from healthy donors was incubated with swine dust, phytohaemagglutinin (positive control) or Roswell Park Memorial Institute 1640 medium (negative control), and the production of intracellular interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, interleukin (IL)4 and IL-12 was analysed by flow cytometry. Cells were double stained for specific cell surface markers on T-cells (CD3+, CD4+, CD8+), natural killer (NK) cells (CD56+ CD16+) and monocytes (defined as CD14+ cells). Following 1 h of incubation of whole blood with swine dust, CD14+ cells produced high levels of TNF-alpha and IL-12, whereas CD3+, CD4+ and CD8+ T-cells and CD56+ CD16+ NK cells required a longer incubation time (22 h) to produce IFN-gamma and TNF-alpha. When antibodies that block the IL-12 receptor were added to whole blood incubated with swine dust, NK cell production of IFN-gamma was attenuated and CD69 expression on CD3+ cells decreased. In conclusion, this study indicates that swine dust can, at least in part, stimulate phagocytic cells to activate natural killer cells and T-lymphocytes through the production of interleukin-12.

Exhaled nitric oxide and bronchial responsiveness in healthy subjects exposed to organic dust

Inhalation of organic dust from swine houses causes an intense inflammatory reaction in the respiratory tract, and increased bronchial responsiveness to methacholine in healthy subjects. The aims of the present study were to investigate whether exhaled nitric oxide (NO) is a marker of the inflammation caused by exposure to organic dust (swine dust), whether there is a relationship between an increase in exhaled NO and bronchial responsiveness, and also whether wearing a half-mask influences the airway reaction (assessed by exhaled NO) and the increased bronchial responsiveness. Thirty-three healthy nonatopic, nonsmoking subjects were exposed during 3 h of light work in a swine confinement building. Eleven of the subjects were wearing a half-mask and 22 were unprotected. Lung function, bronchial responsiveness and exhaled NO were measured before and after exposure. The provocative concentration causing a 20% fall in forced expiratory volume in one second fell by 2.7 (2.1-4.1) (median (25th-75th percentiles)) doubling concentration steps in subjects without a half-mask and by 1.5 (0.9-2.9) doubling concentration steps in subject wearing a mask. Exhaled NO increased from 7.5 (5.7-13.7) parts per billion (ppb) before to 13.4 (10.5-17.5) ppb after exposure in the unprotected group and was unaltered (8.3 (6.1-14.1) to 8.6 (6.6-14.6) ppb) in the group wearing a half-mask. There was no correlation between NO increase and provocative dose causing a 20% fall in the forced expiratory volume in one second decrease. In conclusion, bronchial responsiveness and exhaled nitric oxide increased after exposure to a swine confinement facility. Half-mask abolished the increase in exhaled nitric oxide levels, but influenced the increase in bronchial responsiveness to a minor extent. These results indicate that these two outcome measures reflect different aspects of airway inflammation induced by exposure to a farming environment.