Induction of macrophage matrix metalloproteinase biosynthesis by surfactant protein D.

Recent studies strongly suggest that surfactant protein D (SP-D) plays important roles in pulmonary host defense and the regulation of immune and inflammatory reactions in the lung. Although SP-D can bind to alveolar macrophages and can elicit their chemotaxis, relatively little is known about the direct cellular consequences of SP-D on the function of these cells. Because matrix metalloproteinases (MMPs) are synthesized in increased amounts in response to various proinflammatory stimuli, we investigated the capacity of SP-D to modulate the production of MMPs by freshly isolated human alveolar macrophages. Unexpectedly we found that recombinant rat SP-D dodecamers selectively induce the biosynthesis of collagenase-1 (MMP-1), stromelysin (MMP-3), and macrophage elastase (MMP-12) without significantly increasing the production of tumor necrosis factor alpha and interleukin-1beta. SP-D did not alter the production of these MMPs by fibroblasts. Phosphatidylinositol, a surfactant-associated ligand that interacts with the carboxyl-terminal neck and carbohydrate recognition domains of SP-D, inhibited the SP-D-dependent increase in MMP biosynthesis. A trimeric, recombinant protein consisting of only the neck and carbohydrate recognition domain did not augment metalloproteinase production, suggesting that the stimulatory effect on MMP production depends on an appropriate spatial presentation of trimeric lectin domains. Although SP-D dodecamers can selectively augment metalloproteinase activity in vitro, this effect may be competitively inhibited by tissue inhibitors of metalloproteinases or surfactant-associated ligands in vivo.

Telemedical education: teaching spirometry on the Internet.

Advances in portable equipment have led to routine spirometry testing outside of formal pulmonary function laboratories. Practitioners ordering these tests are not formally trained in spirometry interpretation. Providing effective off-site training can be challenging. Our objective was to develop a remotely accessible computer-based tutorial for teaching spirometry interpretation to nonpulmonologists. We designed an educational module that was accessible via the Internet and tested by 65 medical trainees at a major university medical center. In addition, the module was posted within the Virtual Hospital on the World Wide Web. Increases in spirometry interpretative skills were assessed using pre- and post-tests submitted electronically. The spirometry module significantly improved spirometry interpretation by nonspecialist trainees. This improvement included a broad increase in knowledge base and was observed independent of training level and prior spirometry reading experience. We conclude that computer-based tutorials can effectively train off-site practitioners in spirometry interpretation. This technology allows for the dissemination of educational material from a central site of expertise and provides a valuable adjunct to limited teaching resources.