Effect of Cell Cycle on Cell Surface Expression of Voltage-Gated Sodium Channels and Na+,K+-ATPase.

Voltage-gated sodium channels (VGSCs) are the target for many therapies. Variation in membrane potential occurs throughout the cell cycle, yet little attention has been devoted to the role of VGSCs and Na+,K+-ATPases. We hypothesized that in addition to doubling DNA and cell membrane in anticipation of cell division, there should be a doubling of VGSCs and Na+,K+-ATPase compared to non-dividing cells. We tested this hypothesis in eight immortalized cell lines by correlating immunocytofluorescent labeling of VGSCs or Na+,K+-ATPase with propidium iodide or DAPI fluorescence using flow cytometry and imaging. Cell surface expression of VGSCs during phases S through M was double that seen during phases G0-G1. By contrast, Na+,K+-ATPase expression increased only 1.5-fold. The increases were independent of baseline expression of channels or pumps. The variation in VGSC and Na+,K+-ATPase expression has implications for both our understanding of sodium's role in controlling the cell cycle and variability of treatments targeted at these components of the Na+ handling system.

Impact of participation in a community-based intimate partner violence prevention program on medical students: a multi-center study.

BACKGROUND: Physicians are generally poorly trained to recognize, treat or refer adolescents at risk for intimate partner violence (IPV). Participation in community programs may improve medical students' knowledge, skills, and attitudes about IPV prevention. OBJECTIVE: To determine whether the experience of serving as educators in a community-based adolescent IPV prevention program improves medical students' knowledge, skills, and attitudes toward victims of IPV, beyond that of didactic training. PARTICIPANTS: One hundred and seventeen students attending 4 medical schools. DESIGN: Students were randomly assigned to didactic training in adolescent IPV prevention with or without participation as educators in a community-based adolescent IPV prevention program. Students assigned to didactic training alone served as community educators after the study was completed. MEASUREMENT: Knowledge, self-assessment of skills and attitudes about intimate partner violence and future plans to pursue outreach work. RESULTS: The baseline mean knowledge score of 10.25 improved to 21.64 after didactic training (p