To investigate the role of CD8+ T lymphocytes in recovery from influenza pneumonia, we used transgenic mice either homozygous (-/-) or heterozygous (+/-) for beta 2-microglobulin (beta 2-M) gene disruption. These mice lack major histocompatibility complex-restricted class I (CD8+) T cells. We found that after challenge with a nonlethal influenza virus, the beta 2-M (-/-) mice had significantly delayed pulmonary viral clearance. Furthermore, after challenge with a more virulent influenza virus, the beta 2-M (-/-) mice had a significantly higher mortality rate than did control mice. Thus, CD8+ T cells are important in recovery from virulent influenza infections, but other host defense mechanisms can clear the respiratory tract of more benign infections.

The nature of discomfort and level of exertion associated with wearing respiratory protection in the health care workplace are not well understood. Although a few studies have assessed these topics in a laboratory setting, little is known about the magnitude of discomfort and the level of exertion experienced by workers while they deliver health care to patients for prolonged periods. The purpose of this study was to determine the magnitude of discomfort and level of exertion experienced by health care workers while wearing respiratory protection for periods up to 8 hr when performing their typical occupational duties. This project was a multiple cross-over field trial of 27 health care workers, aged 24-65, performing their typical, hospital-based occupational duties. Each participant served as his/her own control and wore one of seven respirators or a medical mask for 8 hr (or as long as tolerable) with interposed doffing periods every 2 hr. Self-perceived discomfort and exertion were quantified before each doffing: self-perceived level of discomfort using a visual analog scale, and self-perceived level of exertion using a Borg scale. Overall, and as would be expected, discomfort increased over time with continual respirator use over an 8-hr period. Interestingly, exertion increased only marginally over the same time period. The relatively low level of exertion associated with eight respiratory protective devices, including models commonly used in the U.S. health care workplace, is not likely to substantially influence workers' tolerability or occupational productivity. However, the magnitude of discomfort does appear to increase significantly over time with prolonged wear. These results suggest that respirator-related discomfort, but not exertion, negatively influences respirator tolerance over prolonged periods. Discomfort may also interfere with the occupational duties of workers.

Initial conservative therapy is applied to all cases of chylothorax (CTx) with expected excellent outcomes. The indication for aggressive surgical treatment of early CTx remains uncertain and requires rigorous scientific scrutiny. Lymphangiography and lymphoscintigraphy are useful to localize the leak and assess thoracic duct patency as well as to differentiate partial from complete thoracic duct transection. The aetiology of the CTx, flow rate and patient condition dictate the preferred management. Octreotide/somatostatin and etilefrine therapy is highly efficacious in the conservative management of CTx. For patients in whom conservative management fails, those who are good surgical candidates, and those in whom the site of the leak is well identified, surgical repair and/or ligation using minimally invasive techniques is highly successful with limited adverse outcomes. Similarly, if the site of the chylous effusion cannot be well visualized, a thoracic duct ligation via video-assisted thoracic surgery is the gold standard approach. A pleuroperitoneal or less often a pleurovenous shunt is a final option and may be curative in some patients.