Toni A. Bledsoe

Acute Upper and Lower Respiratory Effects in Wildland Firefighters

Objectives: To assess acute respiratory effects experienced by wildland firefighters. Methods: We studied two Interagency Hotshot Crews with questionnaires, spirometry, and measurement of albumin, eosinophilic cationic protein (ECP), and myeloperoxidase (MPO) as indicators of inflammation in sputum and nasal lavage fluid. Assessments were made preseason, postfire, and postseason. Results: Fifty-eight members of the two crews had at least two assessments. Mean upper and lower respiratory symptom scores were higher postfire compared to preseason (P < 0.001). The mean forced expiratory volume in 1 second was lower postfire compared to preseason (P < 0.001) and then recovered by postseason. Individual increases in sputum and nasal ECP and MPO from preseason to postfire were all significantly associated with postfire respiratory symptom scores. Conclusions: Wildland firefighting was associated with upper and lower respiratory symptoms and reduced forced expiratory volume in 1 second. Within individuals, symptoms were associated with increased ECP and MPO in sputum and nasal lavage fluid. The long-term respiratory health impact of wildland firefighting, especially over multiple fire seasons, remains an important concern.

Natural rubber latex: glove use, sensitization, and airborne and latent dust concentrations at a Denver hospital.

Exposure to natural rubber latex may cause immediate hypersensitivity reactions. Published latex sensitization prevalence rates range from 2.9% to 22% among health care workers, and from 0.12% to about 20% of occupationally unexposed populations. In this study, self-administered questionnaires addressed job and personal characteristics, glove use, and symptoms in two groups of hospital workers: those who regularly used latex gloves and those who did not. Serum was tested for latex-specific immunoglobulin E. Air, surface, and air-filter dust samples for natural rubber latex were collected. The prevalence of latex sensitization was 6.3% in the non-users and 6.1% in the latex glove users (P = 0.9); 81.3% of sensitized workers were atopic compared with 59.5% of non-sensitized workers (P < 0.05). Reporting of work-related hand dermatitis was more common in the latex glove users (23.4%) than in the non-users (4.9%), as were rhino-conjunctivitis (16.3% and 7.9%, respectively, [P < 0.01]), and hand urticaria (9.9% and 2.1%, respectively, [P < 0.01]). There was no significant difference in work-related symptoms between the sensitized and non-sensitized workers. Environmental concentrations of latex were higher in the work areas of the non-sensitized workers, but higher in the clinical than in the non-clinical areas. Occupational latex glove use was not a risk factor for sensitization.

Occupational sensitization to soy allergens in workers at a processing facility

Background Exposure to soy antigens has been associated with asthma in community outbreaks and in some workplaces. Recently, 135 soy flake processing workers (SPWs) in a Tennessee facility were evaluated for immune reactivity to soy. Allergic sensitization to soy was common and was five times more prevalent than in health care worker controls (HCWs) with no known soy exposure.

Adverse respiratory outcomes associated with occupational exposures at a soy processing plant

This study aimed to characterise the relationship between adverse health outcomes and occupational risk factors among workers at a soy processing plant. A questionnaire, spirometry, methacholine challenge, immune testing and air sampling for dust and soy were offered. Prevalence ratios (PRs) of respiratory problems from comparisons with the US adult population were calculated. Soy-specific immunoglobulin (Ig)G and IgE among participants and healthcare worker controls were compared. Associations between health outcomes and potential explanatory variables were examined using logistic regression. 147 (52%) out of 281 employees, including 66 (70%) out of 94 production workers, participated. PRs were significantly elevated for wheeze, sinusitis, ever-asthma and current asthma. Participants had significantly higher mean concentrations of soy-specific IgG (97.9 mg·L−1 versus 1.5 mg·L−1) and prevalence of soy-specific IgE (21% versus 4%) than controls. Participants with soy-specific IgE had three-fold greater odds of current asthma or asthma-like symptoms, and six-fold greater odds of work-related asthma-like symptoms; the latter additionally was associated with production work and higher peak dust exposures. Airways obstruction was associated with higher peak dust. Work-related sinusitis, nasal allergies and rash were associated with reported workplace mould exposure. Asthma and symptoms of asthma, but not other respiratory problems, were associated with immune reactivity to soy.

Respiratory Morbidity in a Coffee Processing Workplace With Sentinel Obliterative Bronchiolitis Cases

RATIONALEnObliterative bronchiolitis in former coffee workers prompted a cross-sectional study of current workers. Diacetyl and 2,3-pentanedione levels were highest in areas for flavoring and grinding/packaging unflavored coffee.nnnMETHODSnWe interviewed 75 (88%) workers, measured lung function, and created exposure groups based on work history. We calculated standardized morbidity ratios (SMRs) for symptoms and spirometric abnormalities. We examined health outcomes by exposure groups.nnnRESULTSnSMRs were elevated 1.6-fold for dyspnea and 2.7-fold for obstruction. The exposure group working in both coffee flavoring and grinding/packaging of unflavored coffee areas had significantly lower mean ratio of forced expiratory volume in 1 s to forced vital capacity and percent predicted mid-expiratory flow than workers without such exposure.nnnCONCLUSIONnCurrent workers have occupational lung morbidity associated with high diacetyl and 2,3-pentanedione exposures, which were not limited to flavoring areas.

Detection of microbial antigens in metal working fluids

In recent years there have been several reports of hypersensitivity pneumonitis (HP) or an HP-like illness occurring among machinists working with water-based metal working fluids (MWF). Microbial contamination of the MWF is common and microbial agents have been suspected to be causal agents for the HP-like illness, but no specific etiologic agent has been identified to date. In particular, gram negative bacteria and biocide resistant mycobacterial species may colonize the MWF, and may stimulate an inflammatory response if inhaled. Because direct culture techniques provide data only about viable organisms present at the time the sample was collected, we have been evaluating techniques to detect microbial substances (antigens) that may be present and persist in the MWF. We have found that the endotoxin of gram negative bacteria can be detected in MWF using the limulus amoebocyte lysate (LAL) assay, and may be present in high concentrations. In addition, MWF samples have been analyzed by Western Blot techniques using polyclonal antibodies to mycobacteria to demonstrate the presence of mycobacterial antigens in these samples. The use of non-culture-based techniques for the assessment of microbial contamination of MWF may help to determine the role of microorganisms in the etiology of HP associated with MWF exposure.

A Murine Monoclonal Antibody with Broad Specificity for Occupationally Relevant Diisocyanates

Diisocyanates (dNCOs) used in industrial applications are well known low molecular weight allergens. Occupational exposure is associated with adverse health outcomes including allergic sensitization and occupational asthma. In this study, we report the production and initial characterization of a dNCO-hapten specific murine IgM monoclonal antibody (mAb). Female BALB/c mice were immunized intraperitoneally with 25 μg of 4,4′-methylene diphenyl diisocyanate (MDI)-keyhole limpet hemocyanin. Following six biweekly booster immunizations, splenocytes were recovered and fused to Sp2/0-Ag14 murine myeloma cell line for hybridoma production. Hybridomas were then screened in a solid-phase indirect enzyme-linked immunosorbent assay (ELISA) against 40:1 4,4′-MDI– human serum albumin (HSA). mAb reactivity to dNCO-HSA conjugates and dNCO-HSA spiked human serum were characterized using a sandwich ELISA. One hybridoma produced a multimeric IgM mAb (15D4) that reacted with 4,4′-MDI-HSA. Sandwich ELISA analysis demonstrated comparable reactivity with other occupationally relevant dNCO-HSA adducts, including 2,4-toluene diisocyanate (TDI)-HSA, 2,6-TDI-HSA, and 1,6-hexamethylene diisocyanate (HDI)-HSA, but not other electrophilic chemical HSA conjugates. The limit of quantification (LOQ) of 4,4′-MDI-HSA, 2,4-TDI-HSA, 2,6-TDI-HSA, and 1,6-HDI-HSA sandwich ELISAs were 567.2, 172.7, 184.2, and 403.5 ng/mL (8.67, 2.60, 2.77, and 6.07 pmol/mL), respectively. In contrast, experiments using dNCO-supplemented human sera showed an increase in the detectable limit of the assay. A mAb has been produced that has potential utility for detecting mixed diisocyanate exposures in occupational environments. The mAb may have additional utility in the standardization of specific IgE detection immunoassays as well as chromatographic-mass spectrometric methods to enrich dNCO adducted HSA in the plasma of occupationally exposed workers.

A Computer-Controlled Whole-Body Inhalation Exposure System for the Oil Dispersant COREXIT EC9500A

An automated whole-body inhalation exposure system capable of exposing 12 individually housed rats was designed to examine the potential adverse health effects of the oil dispersant COREXIT EC9500A, used extensively during the Deepwater Horizon oil spill. A computer-controlled syringe pump injected the COREXIT EC9500A into an atomizer where droplets and vapor were formed and mixed with diluent air. The aerosolized COREXIT EC9500A was passed into a customized exposure chamber where a calibrated light-scattering instrument estimated the real-time particle mass concentration of the aerosol in the chamber. Software feedback loops controlled the chamber aerosol concentration and pressure throughout each exposure. The particle size distribution of the dispersant aerosol was measured and shown to have a count median aerodynamic diameter of 285 nm with a geometric standard deviation of 1.7. The total chamber concentration (particulate + vapor) was determined using a modification of the acidified methylene blue spectrophotometric assay for anionic surfactants. Tests were conducted to show the effectiveness of closed loop control of chamber concentration and to verify chamber concentration homogeneity. Five automated 5-h animal exposures were performed that produced controlled and consistent COREXIT EC9500A concentrations (27.1 ± 2.9 mg/m3, mean ± SD).

Allergic sensitization in Canadian chronic rhinosinusitis patients

BackgroundChronic rhinosinusitis (CRS) is a societal burden and cause of morbidity in Canada; however, the prevalence of allergic sensitization in Canadian CRS patients has remained poorly characterized.ObjectiveIn this study, we used skin prick test (SPT) and specific immunoglobulin E (sIgE) and G (sIgG) titers to regionally relevant allergen sources in order to determine whether allergic sensitization is more prevalent in CRS patients compared to chronic idiopathic urticaria (CIU) control patients.MethodsOne hundred and fifty eight subjects (19–70xa0years of age) were recruited into the study. 101 subjects had a confirmed diagnostic history of CRS and 57 subjects with a clinical diagnosis of CIU were recruited as controls. Enrolled subjects underwent SPT to a panel of perennial and seasonal allergens and sIgE titers were quantified to selected environmental allergen mixes (grass, mold, and tree species) using Phadia ImmunoCAP. sIgG was additionally quantified to Alternaria alternata, Aspergillus versicolor, Cladosporium herbarum, and Stachybotrys atra. Differences between CRS and control CIU patient SPT and serological data were examined by chi-squared analysis and analysis of variance.ResultsReactivity to at least one SPT extract occurred in 73% of CRS patients. Positive SPT reactivity to A. alternata (odds ratio (OR): 4.34, 95% confidence interval: 1.57, 12.02), cat (OR: 3.23, 95% CI: 1.16, 9.02), and ragweed (OR: 2.31, 95% CI: 1.02, 5.19) extracts were more prevalent in patients with CRS (pu2009<u20090.05). Although dust mite and timothy grass sensitization approached statistical significance in the chi-squared analysis of SPT data, other common perennial and seasonal allergens were not associated with CRS. No statistically significant differences were observed between mean sIgE and sIgG titers in CRS and control patients.ConclusionsThis study supports previous data that suggests A. alternata sensitization is associated with CRS; however, these findings additionally highlight the contribution of other regionally important allergens including cat and ragweed.

Post-hire asthma among insect-rearing workers.

Objective: To evaluate the incidence of post-hire asthma (PHA) among insect-rearing workers, defined as asthma, the symptoms of which appeared after hire at the current workplace. Methods: We surveyed the health of workers at three insect-rearing facilities and an associated office facility. We calculated the incidence and estimated hazard ratios for PHA. Results: Post-hire asthma incidence in 157 insect-rearing workers was 16.2 per 1000 person-years compared with 9.2 per 1,000 person-years in 70 office workers. Workers with predominant exposure to Lepidoptera had an incidence of 26.9 per 1000 person-years and a hazard ratio of 5.5 (95% confidence interval: 1.6 to 23.9) adjusted for sex, race, and parental asthma. In contrast, the presence of specific immunoglobulin E to Lepidoptera antigens was not associated with PHA. Conclusion: Insect-rearing workers had a high incidence of PHA, primarily accounted for by workplace exposure to Lepidoptera.