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The acute effects of pure inhaled glucan on respiratory inflammation remain inconclusive and not sufficiently examined with regards to the simultaneous interaction of glucan, endotoxin (lipopolysaccharide, LPS), and house dust in airway inflammation. This study aims at determining effects of simultaneous exposure to office dust and glucan on nasal and pulmonary inflammation. This is relevant for humans with occupational exposure in waste handling and farming and buildings with mold problems. Office dust collected from Danish offices was spiked with 1% (1-3)-beta-glucan (curdlan). Guinea pig nasal cavity volume was measured by acoustic rhinometry (AR) and animals were exposed by inhalation for 4 h to curdlan-spiked dust, unspiked dust, purified air (negative controls), or LPS (positive controls). After exposure (+5 h) or the following day (+18 h), measurements were repeated by AR and followed by bronchoalveolar lavage (BAL). Total and differential cell counts, interleukin (IL)-8 in BAL fluid, and change in nasal volume were compared between groups. A 5-10% increase in nasal volume was seen for all groups including clean air except for a significant 5% decrease for spiked-dust inhalation (+18 h). No marked differences were observed in BAL cells or IL-8 except in LPS-exposed controls. The delayed decrease of nasal cavity volume after exposure to glucan spiked dust suggests a slow effect on the upper airways for curdlan and office dust together, though no pulmonary response or direct signs of inflammation were observed. Glucan-spiked office dust exposures produced a delayed nasal subacute congestion in guinea pigs compared to office dust alone, but extrapolated to nasal congestion in humans, paralleling the nasal congestion seen in human volunteers exposed to the same dust, this may not have clinical importance.

Background/Question/MethodsThe survival of animal populations is strongly influenced by the individuals’ ability to forage efficiently, yet there are few studies of how populations respond when disturbances cause animals to deviate from their natural foraging behavior. Animals that respond to disturbances by moving away are prevented from accessing the food in the disturbed areas and may also be prevented from dispersing among areas where food is available at different times of the year. Such disturbance effects may play a particularly large role for marine mammals that live in environments that are increasingly exposed to noise from ships, wind turbines, etc. In the present study we investigate how the dynamics of the harbor porpoise population (Phocoena phocoena) in the inner Danish waters is influenced by disturbances using an agent- based simulation model. In the model animal movement, and hence the animals’ ability to forage efficiently and to sustain their energy intake, is influenced by noise emitted from wind turbines and ships. The energy levels in turn affect their survival. The fine-scale movements of the simulated animals was governed by a spatial memory, which allowed the model to produce realistic movement patterns in scenarios where animals were not exposed to noise.Results/ConclusionsThe main results of the study were that the effects of disturbances were highly dependent on how fast the food recovered after being eaten, but that the long-term survival of the population was not jeopardized even when disturbances were simulated to have a relatively large and persistent effect on the behavior of individual animals. Porpoises were simulated to move away from noisy objects, preventing them from returning to the known food patches in that area. This resulted in decreasing energy reserves and an increasing risk of starvation. When food was simulated to recover slowly, the population effects of the disturbances was small because little food would have been available to porpoises in the known food patches even if they had been able to return. Interestingly the negative consequences of disturbances were counterbalanced by increases in the amount of food available for the remaining animals. This illustrates that it is important to consider density-dependent feedback mechanisms when evaluating the population consequences of anthropogenic disturbances.