RESUMEN
OBJECTIVE: The authors examine the dynamics and the impact of all-campus events on pH1N1 spread at Bates College in fall 2009, with comparisons to 3 other campuses. PARTICIPANTS: Students (N = 285) presented or called in to the Bates Health Center with symptoms consistent with influenza-like illness. METHODS: Health Center staff at Bates collected data on the outbreak; data from other colleges are from Web sites and journal articles. Data were analyzed using a mathematical model for influenza. RESULTS: Bates held 2 vaccine clinics mid-outbreak. The data are consistent with the hypothesis that the vaccine clinics may have altered routine student interactions, facilitating transmission of pH1N1 among students who otherwise might not have encountered each other. CONCLUSION: The vaccine clinics, held when vaccine became available, were too late to halt transmission. The disruptions to campus rhythms due to the vaccine clinics may instead have contributed to pH1N1 spread.
Asunto(s)
Brotes de Enfermedades/estadística & datos numéricos , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/prevención & control , Medición de Riesgo/métodos , Estudiantes/estadística & datos numéricos , Universidades/estadística & datos numéricos , Humanos , Vacunas contra la Influenza , Gripe Humana/epidemiología , Maine/epidemiología , Modelos Teóricos , Servicios de Salud para Estudiantes , Estudiantes/psicologíaRESUMEN
PURPOSE: To investigate plasmid DNA interactions with liposomes prepared from dimyristoylglyceroethylphosphocholine (EDMPC) and DOPE using high sensitivity differential scanning calorimetry (HSDSC). MATERIALS AND METHODS: Large unilamellar liposomes of EDMPC with DOPE (mol ratio 0-50%) were prepared. Plasmid DNA was added to give a final DNA/lipid (-/+) charge ratio of 0.5. Samples were placed into an HSDSC and cooled to 3 degrees C, held isothermally for 30 min and then the temperature was ramped to 120 degrees C at a rate of 1 degree C/min. RESULTS: On heating EDMPC liposomes, the main phase transition occurred at 21.2 degrees C, with a low temperature shoulder on the endothermic peak. At low DOPE concentrations the main phase transition temperatures and enthalpies of transition were lower than for pure EDMPC, with a peak corresponding to a pure EDMPC phase occurring at DOPE concentrations of 12-17 mol%. At 50 mol%, no main transition endotherm was observed. DNA solution produced two endothermic peaks with numerous 'satellite' peaks indicating thermal denaturation. DNA binding to EDMPC changed the shape of the thermogram, indicating alteration in lipid packing within the bilayer. DNA induced demixing in the bilayers of DOPE-containing liposomes. CONCLUSION: HSDSC provided information for characterizing liposome formulations and DNA interactions with such vesicles.