J Agromedicine
January 2025
Objective: Increased risk of occupational exposure to bioaerosols has long been recognized in livestock operations including dairy facilities. Spanning the inhalable fraction (0-100 μm), dairy bioaerosols comprise a wide variety of inflammatory components that deposit in the nasopharyngeal region. The resultant inflammatory response from bioaerosol exposure is likely driving the increased prevalence of respiratory disease observed in dairy workers.
View Article and Find Full Text PDFJ Occup Environ Hyg
January 2023
Livestock workers experience an increased burden of bioaerosol-induced respiratory disease including a high prevalence of rhinosinusitis. Dairy operations generate bioaerosols spanning the inhalable size fraction (0-100 μm) containing bacterial constituents such as endotoxin. Particles with an aerodynamic diameter between 10 and 100 μm are known to deposit in the nasopharyngeal region and likely affect the upper respiratory tract.
View Article and Find Full Text PDFFrancisella tularensis is a highly infectious intracellular bacterium that causes tularemia by invading and replicating in mammalian myeloid cells. Francisella primarily invades host macrophages, where it escapes phagosomes within a few hours and replicates in the cytoplasm. Less is known about how Francisella traffics within macrophages or exits into the extracellular environment for further infection.
View Article and Find Full Text PDFObjective: Limited studies have examined effects of bioaerosols on the respiratory health of dairy workers; previous findings have been inconsistent across populations.
Methods: Using a repeated measures design, exposures to dust, bioaerosols, and ozone were assessed and pre- and post-shift spirometry was performed for dairy workers (n = 36). Workers completed 1 to 8 visits.
Methods used to prepare bone marrow-derived macrophages (BMDMs) may influence the outcomes of immunological assays in which they are used. Supernatant conditioned by growth of L929 cells has often been used to generate mouse macrophages from bone marrow in vitro but is subject to lot-to-lot variability. To reduce experimental variability and to standardize techniques across laboratories, we investigated recombinant M-CSF (rM-CSF) as an alternative supplement for BMDM maturation in the context of macrophage infection, using the intracellular bacterium Live Vaccine Strain (LVS) of Francisella tularensis as a prototype.
View Article and Find Full Text PDFDairy workers experience a high degree of bioaerosol exposure, composed of an array of biological and chemical constituents, which have been tied to adverse health effects. A better understanding of the variation in the magnitude and composition of exposures by task is needed to inform worker protection strategies. To characterize the levels and types of exposures, 115 dairy workers grouped into three task categories on nine farms in the high plains Western United States underwent personal monitoring for inhalable dust, endotoxin, 3-hydroxy fatty acids (3-OHFA), muramic acid, ergosterol, and ammonia through one work shift.
View Article and Find Full Text PDFEndocytosis is a well-conserved process by which cells invaginate small portions of the plasma membrane to create vesicles containing extracellular and transmembrane cargo proteins. Dozens of proteins and hundreds of specific binding interactions are needed to coordinate and regulate these events. Saccharomyces cerevisiae is a powerful model system with which to study clathrin-mediated endocytosis (CME).
View Article and Find Full Text PDFPan1 is a multi-domain scaffold that enables dynamic interactions with both structural and regulatory components of the endocytic pathway. Pan1 is composed of Eps15 Homology (EH) domains which interact with adaptor proteins, a central region that is responsible for its oligomerization and C-terminal binding sites for Arp2/3, F-actin, and type-I myosin motors. In this study, we have characterized the binding sites between Pan1 and its constitutive binding partner End3, another EH domain containing endocytic protein.
View Article and Find Full Text PDFObjective: Organic dust inhalation has been associated with adverse respiratory responses among agricultural workers. We evaluated factors that may confer increased susceptibility to these health effects.
Methods: We quantified personal work shift exposures to inhalable dust, endotoxin, and its 3-hydroxy fatty acid constituents, and evaluated changes in pulmonary function among 137 grain elevator, cattle feedlot, dairy, and corn farm workers.
Lipids are essential for cellular function as sources of fuel, critical signaling molecules and membrane components. Deficiencies in lipid processing and transport underlie many metabolic diseases. To better understand metabolic function as it relates to disease etiology, a whole animal approach is advantageous, one in which multiple organs and cell types can be assessed simultaneously in vivo.
View Article and Find Full Text PDFJ Toxicol Environ Health A
January 2010
The adverse respiratory effects of agricultural dust inhalation are mediated in part by endotoxin, a constituent of gram-negative bacterial cell walls. This study quantified personal work-shift exposures to inhalable dust, endotoxin, and its reactive 3-hydroxy fatty acid (3-OHFA) constituents among workers in grain elevators, cattle feedlots, dairies, and on corn farms. Exposures were compared with post-work-shift nasal lavage fluid inflammation markers and respiratory symptoms.
View Article and Find Full Text PDFObjective: Anti-smoking PSAs are not always effective in reducing cigarette smoking, and there is a lack of research into mechanisms through which PSAs affect the attitudes and behaviors of viewers. The present research was designed to better understand how smokers and non-smokers process anti-smoking ads.
Design: In a repeated measures design, the accessibility of smokers' (N = 70) and non-smokers' (N = 96) attitudes toward and norms concerning smoking were assessed and then their reactions to four anti-smoking PSAs were measured.
Staphylococcal enterotoxin B induces toxic shock and is a major virulence factor of staphylococcal diseases. We examined the effects of systemic adenoviral infection on responses to staphylococcal enterotoxin B in a murine model. We found that adenoviral infection markedly increases the severity of liver injury following exposure to staphylococcal enterotoxin B without d-galactosamine sensitization.
View Article and Find Full Text PDFHuman alveolar macrophages are unique in that they have an extended life span in contrast to precursor monocytes. In evaluating the role of sphingolipids in alveolar macrophage survival, we found high levels of sphingosine, but not sphingosine-1-phosphate. Sphingosine is generated by the action of ceramidase(s) on ceramide, and alveolar macrophages have high constitutive levels of acid ceramidase mRNA, protein, and activity.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
August 2004
Airway epithelial cells are often the sites of targeted adenovirus vector delivery. Activation of the host inflammatory response and modulation of signal transduction pathways by adenovirus vectors have been previously documented, including activation of MAP kinases and phosphatidylinositol 3-kinase (PI3-kinase). The effect of activation of these pathways by adenovirus vectors on cell survival has not been examined.
View Article and Find Full Text PDFEffects of adenoviral infection on in vivo responses to LPS mediated by TNF-alpha were evaluated in a murine model. Adenovirus-infected mice showed decreased mortality from fulminant hepatitis induced by administration of LPS or staphylococcal enterotoxin B in the presence of D-galactosamine. Importantly, TNF-alpha resistance genes within adenoviral E3 region were not required, because E1,E3-deleted vectors showed similar effects.
View Article and Find Full Text PDFThe host immune system responds to CpG motifs in bacterial DNA by rapidly producing proinflammatory cytokines. The host response to CpG DNA resembles, in many ways, the response to bacterial lipopolysaccharide (LPS). While both agents can induce a powerful inflammatory response, CpG DNA promotes Th1 and suppresses Th2 immunity.
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