silicon and Pneumonia

Determine whether surface dust grab samples taken from a large military base in Iraq are toxic and respirable.. X-ray diffraction for mineral content, x-ray fluorescence for elemental content, in vivo mouse dust challenges for assessment of histological changes, bronchoalveolar lavage for cytokines, polarizing light microscopy for crystals in lung tissue, and Fluorescence Activated Cell Sorting for cell surface and intracellular markers were utilized.. Camp Victory, Iraq dust taken during wartime contains respirable particles 2.5 microns in size, constituting particulate matter air pollution. Dust particles are angular and have sharp edges. Trace metals (including titanium) calcium and silicon are present. Mice with airway instillation of dust have polarizable crystals in lung and septate inflammation. Regulatory T cells (CD4⁺CD25⁺FOXP3⁺) are decreased in thymus and spleen. Interleukin-2 (IL-2) is upregulated in bronchoalveolar lavage.. Respirable Iraq dust leads to lung inflammation in mice similar to that seen in patients with polarizable crystals, which seem to be titanium.

Topics: Animals; Birefringence; Bronchoalveolar Lavage Fluid; Calcium; Dust; Inhalation Exposure; Interleukin-2; Iraq; Lymphocyte Count; Male; Mice; Mice, Inbred C57BL; Military Facilities; Particulate Matter; Pneumonia; Pulmonary Fibrosis; Silicon; Spleen; T-Lymphocytes, Regulatory; Thymus Gland; Titanium; Up-Regulation

The inflammatory response caused by extracorporeal membrane oxygenation (ECMO) is clearly visible within the first 24 h of cannulation. The inflammatory process affects all areas of the lung, even areas previously spared by the primary disease.. To compare the change in the radiographic signs of inflammatory response to ECMO between poly-methyl pentene and silicon oxygenators.. Retrospective review of neonates and adults pre- and post-replacement of silicon oxygenators with poly-methyl pentene devices. Data were collected from Extracorporeal Life Support Organisation (ELSO) registry forms and patient records. Results were analysed by quantitative and semi-quantitative methods.. There was a significant reduction in the radiographic signs of inflammatory response to ECMO, and a reduction in the time taken to revert to pre-ECMO state in the neonatal poly-methyl pentene group compared to silicon. However, there was no significant reduction in the duration of ECMO runs and the percentage survival between these groups in the neonates. In adults, there was no difference in severity of radiographic signs between groups. However, the inflammatory changes were relatively delayed in the adult poly-methyl pentene group.. Polymethyl pentene (Medos) oxygenators have reduced the host's response phenomenon 'white out' in neonates, and caused a delayed response in adults. This is most likely a consequence of smaller blood contact surface area combined with the effect of heparin coating of the oxygenator membrane. However, recovery was not a function of the type of gas exchange device used.

Topics: Adult; Extracorporeal Membrane Oxygenation; Humans; Infant, Newborn; Oxygenators, Membrane; Pneumonia; Polyenes; Radiography; Retrospective Studies; Silicon

Silica, a known toxin of mononuclear phagocytes, was administered intravenously to mice during Nocardia asteroides pneumonia. Mice that received silica had a sevenfold decrease in the number of peripheral blood monocytes and developed more severe N. asteroides pneumonia than control mice. Lung histology in mice that received silica resembled that of mice with impaired cell-mediated immunity. These results are most consistent with the explanation that silica injures blood monocytes and impairs their contributions to pulmonary host defense.

Topics: Animals; Female; Immunity, Cellular; Injections, Intravenous; Lung; Mice; Mice, Inbred BALB C; Nocardia asteroides; Nocardia Infections; Pneumonia; Silicon

Topics: Animals; Electrodes; Female; Lung; Male; Manganese Poisoning; Pneumonia; Rats; Rats, Inbred Strains; Silicon; Welding

Topics: Adolescent; Adult; Aged; Aluminum; Copper; Humans; Iron; Manganese; Middle Aged; Pneumonia; Silicon; Titanium; Trace Elements