Differential Immunogenicity and Lung Disease-Inducing Potential of Mycobacterium immunogenum Genotypes and Impact of Co-Exposure with Pseudomonas: Optimizing a Mouse Model of Chronic Hypersensitivity Pneumonitis.

Mycobacterium immunogenum (MI) colonizing metalworking fluids (MWFs) has been associated with chronic hypersensitivity pneumonitis (HP) in machinists. However, it is etiologically unclear why only certain mycobacteria-contaminated fluids induce this interstitial lung disease. We hypothesized that this may be due to differential immunogenicity and the HP-inducing potential of MI strains/genotypes as well as the confounding effect of co-inhaled endotoxin-producers. To test this hypothesis, we optimized a chronic HP mouse model in terms of MI antigen dose, timepoint of sacrifice, and form of antigen (cell lysates vs. live cells) and compared six different field-isolated MI strains. Overall, MJY10 was identified as the most immunogenic and MJY4 (or MJY13) as the least immunogenic genotype based on lung pathoimmunological changes as well as Th1 cellular response (IFN-γ release). Infection with MI live cells induced a more severe phenotype than MI cell lysate. Co-exposure with Pseudomonas fluorescens caused a greater degree of lung innate immune response and granuloma formation but a diminished adaptive (Th1) immune response (IFN-γ) in the lung and spleen. In summary, this study led to the first demonstration of differential immunogenicity and the disease-inducing potential of field strains of MI and an interfering effect of the co-contaminating Pseudomonas. The improved chronic MI-HP mouse model and the identified polar pair of MI strains will facilitate future diagnostic and therapeutic research on this poorly understood environmental lung disease.

Evaluation of different feedback designs for target guidance in human controlled robotic cranes: A comparison between high and low performance groups.

Labour shortages and costly operator training are driving the need for digital on-board robotic crane operator support in forestry and construction. This simulator study investigated the effects of sonification (auditory, pitch/loudness) and continuous visual (brightness/size) feedback on aiming movements with a robotic crane for low and high performers. The feedback was designed non-linear and linear. Thirty-six participants controlled a robotic crane bimanually using joysticks across 320 movements. Performance and skill indicators (movement time, accuracy, trajectory, smoothness) as well as satisfaction, and usefulness were assessed. Low-performing participants showed higher movement accuracy, particularly with non-linear pitch feedback compared to visual feedback. High performers exhibited no significant performance improvement in movement time, accuracy, or smoothness. There was no effect of linear or non-linear mapping of the feedback. Additionally, perceived satisfaction was lower with auditory than visual feedback. These results suggest that real-time auditory feedback can enhance operator accuracy whereas acceptance remains challenging.

Hypersensitivity pneumonitis due to metal working fluids: Detection of specific IgG antibodies to microbial antigens.

Occupational exposure to microbially contaminated metal working fluids (MWF) can cause hypersensitivity pneumonitis (HP). An important step in the diagnosis of HP is to identify the triggering antigen by detection of corresponding specific IgG antibodies (sIgG). As commercial sIgG tests are currently not available, protein antigens were prepared from MWF-workplace samples and from MWF-typical bacterial isolates. In 57 % of suspected HP-cases (n = 30) elevated sIgG concentrations were measured to at least one MWF-relevant antigen, of which Mycobacterium immunogenum was most prominent (88 %), followed by Pseudomonas oleovorans and Pseudomonas spec (82 % each), MWF-antigen mix and Pseudomonas alcaliphila (65 % each). Elevated sIgG concentrations to other microorganisms were measured to Micropolyspora faeni (82 %) and Aureobasidium pullulans (77 %). Correlation of sIgG values of all tested microbial antigens showed a significant relationship of MWF-antigen mixture to Pseudomonas antigens, but a low correlation to moulds. These newly prepared MWF-antigens are useful tools for the diagnosis of patients with suspected MWF-HP and are available for further investigations.

Work-Related Musculoskeletal Symptoms among Loggers in the Ark-La-Tex Region.

BACKGROUND: The U.S. logging sector is among the most dangerous industrial sectors, with high fatality and non-fatal injury rates. Limited research has addressed work-related musculoskeletal disorders among logging machine operators (LMOs). The purpose of this study was to estimate the 12-month prevalence of musculoskeletal symptoms and the associated work-related risk factors among LMOs in the Arkansas, Louisiana, and Texas (Ark-La-Tex) logging region. METHODS: A self-administered 93-item questionnaire with six different sections: (1) demographics, (2) lifestyle and medical background, (3) work experience, (4) job training, (5) occupational heat-related stress, and (6) occupational injuries and MSS was administered to LMOs (n = 88) using Qualtrics Mobile Survey Software®. Poisson regression models were used to estimate crude prevalence ratios (PR), adjusted PR [aPR], and corresponding 95% confidence intervals (95% CI). RESULTS: Regarding organizational, ergonomic, and handling equipment occupational factors and 12-month MSS prevalence, the adjusted model controlled for age, BMI, smoking status, and drinking status. For organizational, the most problematic factors for the lower back were performing a task over and over (63.2%) and working very fast, for short periods (60.0%). For ergonomics, the most problematic factor for the lower extremities was awkward or cramped conditions (58.1%) and for the lower back was bending/twisting back awkward (55.9%). Last, for handling equipment, the most problematic for both the lower back and lower extremities was handling or grasping small objects (57.1%). CONCLUSION: Our findings revealed associations between work-related MSS and specific job factors (e.g., organizational, ergonomic, handling equipment, etc.), extreme environmental conditions or environmental, and personal risk factors. In particular, study findings suggest lower back and lower extremities MSS are associated with the a majority of job-related risk factors, lower extremities with extreme environmental conditions, and neck and upper back with personal risk factors.