Curved Tails in Polymerization-Based Bacterial Motility

The curved actin ``comet-tail'' of the bacterium Listeria monocytogenes is a visually striking signature of actin polymerization-based motility. Similar actin tails are associated with Shigella flexneri, spotted-fever Rickettsiae, the Vaccinia virus, and vesicles and microspheres in related in vitro systems. We show that the torque required to produce the curvature in the tail can arise from randomly placed actin filaments pushing the bacterium or particle. We find that the curvature magnitude determines the number of actively pushing filaments, independent of viscosity and of the molecular details of force generation. The variation of the curvature with time can be used to infer the dynamics of actin filaments at the bacterial surface.Comment: 8 pages, 2 figures, Latex2

Forage Research Report, No. 1

Joint research program with the Agricultural Research Service Crop Research Division Tropical & Subarctic Research United States Department of Agricultur

Can patient-reported outcome measures identify cancer patients’ most bothersome issues?

Patient-reported outcome (PRO) questionnaires are being investigated for their ability to aid in individual patient management. We evaluated whether PROs can identify patients' most bothersome quality-of-life issues and compared approaches for interpreting PRO scores. This secondary data analysis included 130 patients with cancer (mean age, 57 years; 71% female) receiving outpatient palliative chemotherapy. Patients completed a PRO (European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire [QLQ-C30]) at up to three consecutive visits and reported one or two of their most bothersome function and symptom issues from categories based on QLQ-C30 domains. We compared two approaches for interpreting PRO scores and identified which way better identified patients' most bothersome issues: worst scores in absolute terms or worst change from the previous time point. For patients reporting one bothersome issue, absolute scores identified it correctly 91% of the time for both function and symptoms versus change scores' accuracy of 40% for function and 26% for symptoms. For patients reporting two bothersome issues, absolute scores identified at least one correctly 98% of the time for both function and symptoms versus change scores' 63% for function and 62% for symptoms. Absolute scores identified both issues correctly 42% of the time for function and 66% of the time for symptoms versus change scores' performance of 23% for both function and symptoms. Absolute scores identify patients' most bothersome quality-of-life issues better than change scores. These results support the use of PROs in clinical practice and suggest that clinicians may want to focus on the worst absolute scores when examining PRO score reports