Table 1.

Size-fractionation of basolateral media on Microcon^® centrifugal filter units

Cutoff (kDa)	Uncoated proticles		ApoA-I-coated proticles
	Eluate	Retentate	Eluate	Retentate
3	93	7	94	6
100	98	2	98	2

BCEC Transwell cultures were incubated in the presence of ¹²⁵I-labeled uncoated or apoA-I-coated proticles (2.5 μg ODN/ml; 4 h). To determine the integrity of proticles after transcytosis across BCEC Transwell cultures, the basolateral media were applied to Microcon^® centrifugal filter units with a cut off of 3 and 100 kDa. After centrifugation (25 min, 10,000 rpm) the radioactivity from the lower (‘eluate’) and the upper compartment (including the ultrafiltration membrane; ‘retentate’) was determined on a γ-counter. Results are expressed as percentage of total radioactivity (total radioactivity detected in the eluate, membrane, and retentate) and represent mean values from duplicate determinations.