PFO closure: rational, procedure and devices.

Patent foramen ovale (PFO) is a common anatomical variant occurring in 20-25% of the population. In most cases, a PFO remains asymptomatic. However it allows for any venous particle such as thrombus, air or vasoactive substances to bypass the lung and enter the arterial circulation. Accordingly, PFO's have been linked to cryptogenic stroke, migraine and decompression illness. While the number of device closures have been increasing the therapy remains controversial as ­ until recently ­ data supporting PFO closure came from non randomized studies only. In this review we will discuss the existing data on PFO closure including results of the three randomized controlled trials comparing device closure with medical therapy in patients with cryptogenic stroke. We will also focus on the implantation technique, the complications and the different devices that are used for this procedure.

Determination of properties of individual liposomes by capillary electrophoresis with postocolumn laser-induced fluorescence detection.

Individual liposome measurements by capillary electrophoresis with postcolumn laser-induced fluorescence detection facilitated the determination of liposome property distributions, two-dimensional plots, and an improved characterization of a liposomal preparation. This advancement in liposome analysis was feasible by using a high-sensitivity postcolumn laser-induced fluorescence detector wired for millisecond response. For each individual liposome containing fluorescein, peak height and migration time were determined. From these measurements the individual entrapped volumes and electrophoretic mobilities were determined. Distribution analysis of these properties facilitated comparison of various liposome dilutions and indicated that the method is reproducible and unaffected by the density of liposomes (10(7)-10(9) liposomes/mL) in the suspension. Furthermore, liposomes showed entrapped volumes that vary from 0.3 to 13 fL with apparent radius varying from 370 nm to 1.8 microns. Two-dimensional plots of reduced mobility versus kappa R (Debye parameter x liposome radius) revealed that the liposomes resuspended from a dried film of phospholipids are heterogeneous in regard to the surface charge density of individual liposomes. The described method has the potential of becoming a new tool for characterization of commercial liposomal preparations and theoretical studies.