Pneumonia caused by Moraxella catarrhalis in haematopoietic stem cell transplant patients. Report of two cases and review of the literature

Moraxella catarrhalis is a gram negative diplococcus that causes a variety of upper and lower respiratory tract infections. Patients with malignant, hematological disorders treated with intensive cytotoxic chemotherapy, and recipients of various forms of haematopoietic stem cell transplant receiving immunosuppressive agents are at high risk of developing severe infections and septic complications. Early detection of the organism and prompt treatment with appropriate antibiotics provide both resolution of the infection and prevention of further consequences. Two patients with haematopoietic stem cell transplant who developed pneumonia caused by M. catarrhalis at King Faisal Specialist Hospital and Research Centre in Riyadh are reported and the literature is reviewed. To our knowledge, these are the first case reports of M. catarrhalis pneumonia in haematopoietic stem cell transplant patients

Surviving Mousepox Infection Requires the Complement System

Poxviruses subvert the host immune response by producing immunomodulatory proteins, including a complement regulatory protein. Ectromelia virus provides a mouse model for smallpox where the virus and the host's immune response have co-evolved. Using this model, our study investigated the role of the complement system during a poxvirus infection. By multiple inoculation routes, ectromelia virus caused increased mortality by 7 to 10 days post-infection in C57BL/6 mice that lack C3, the central component of the complement cascade. In C3−/− mice, ectromelia virus disseminated earlier to target organs and generated higher peak titers compared to the congenic controls. Also, increased hepatic inflammation and necrosis correlated with these higher tissue titers and likely contributed to the morbidity in the C3−/− mice. In vitro, the complement system in naïve C57BL/6 mouse sera neutralized ectromelia virus, primarily through the recognition of the virion by natural antibody and activation of the classical and alternative pathways. Sera deficient in classical or alternative pathway components or antibody had reduced ability to neutralize viral particles, which likely contributed to increased viral dissemination and disease severity in vivo. The increased mortality of C4−/− or Factor B−/− mice also indicates that these two pathways of complement activation are required for survival. In summary, the complement system acts in the first few minutes, hours, and days to control this poxviral infection until the adaptive immune response can react, and loss of this system results in lethal infection

Differential effects of nicotine on alcohol consumption in men and women

Nicotine and alcohol are frequently co-used, suggesting that use of one drug may facilitate use of the other. Furthermore, because men and women differ in their responses to both drugs, it is possible that men and women also differ in their responses to the combination of nicotine and alcohol.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46375/1/213_2006_Article_338.pd