Characterization of two blood-brain barrier mimicking cell lines: distribution of lectin-binding sites and perspectives for drug delivery.

In the present study plant lectins with distinct sugar specificities were applied to two blood-brain barrier (BBB) mimicking cell lines, namely human ECV304 and porcine brain microvascular endothelial cells PBMEC/C1-2 in order to elucidate their glycosylation pattern and to evaluate the lectin-cell interaction for lectin-mediated targeting. The bioadhesive properties of fluorescein-labeled lectins were investigated with monolayers as well as single cells using fluorimetry and flow cytometry, followed by confirmation of the specificity of binding. For PBMEC/C1-2 layers highest binding capacity was found for wheat germ agglutinin (WGA), followed by Dolichus biflorus agglutinin (DBA) whereas single cell experiments revealed a predominance of DBA only. Analyzing ECV304 monolayers and single cells, WGA yielded the strongest interaction without any changes during cultivation. The binding capacities of the other lectins increased significantly during differentiation. As similar results to primary cells and brain sections were observed, both cell lines seem to be suitable as models for lectin-interaction studies. Thus, an additional focus was set on the mechanisms involved in uptake and intracellular fate of selected lectins. Cytoinvasion studies were performed with WGA for human ECV304 cells and WGA as well as DBA for PBMEC/C1-2 cells. For both lectins, the association rate to the cells was dependent on temperature which indicated cellular uptake.

Alteration of the glycocalyx of two blood-brain barrier mimicking cell lines is inducible by glioma conditioned media.

Recent studies showed that glioma conditioned medium is able to induce blood-brain barrier properties in in vitro models. In this regard, it was investigated whether glioma conditioned medium can also influence the lectin-binding capacity of blood-brain barrier in vitro models. For the presented study cell lines PBMEC/C1-2 and ECV304 were chosen because it was previously shown that glioma conditioned medium was able to induce specific blood-brain barrier properties in these cell lines. Six different plant lectins (WGA, STL, LCA, UEA-I, DBA, PNA) with distinct sugar specificities were applied in order to elucidate the glycosylation patterns of cell line PBMEC/C1-2 and ECV304. Lectin-binding studies were carried out with monolayers as well as with single cells. In the case of PBMEC/C1-2 monolayers, results showed a significant increase of the binding of lectins WGA, STL, UEA-I, DBA and PNA after application of 25 pmol lectin when cultured in media containing soluble factors derived from glioma cell line C6, whereas the binding capacity for LCA remained similar. For ECV304 monolayers, a significant decrease of WGA, STL and LCA was observable, whereas UEA-I binding increased in comparison to cells grown in the corresponding basal growth medium without soluble C6 factors. Single cell studies showed less significant, but similar changes in the lectin-interactions with the cell surfaces. In conclusion, it was shown that soluble factors derived from glioma cell line C6 can modulate the "glycocalyx" of blood-brain barrier mimicking cell lines.

Applying blood-brain barrier in vitro models to study the influence of drugs on endothelial cells--effects of selected COX-inhibitors.

The influence of three cyclooxygenase (COX) inhibitors (indometacin, lornoxicam and celecoxib) with different COX-1/COX-2 profiles on endothelial cells using in vitro blood-brain barrier (BBB) models was investigated. For the experiments two BBB mimicking cell lines (PBMEC/C1-2 and ECV304) and primary human umbilical vein endothelial cells (HUVEC) were used. In preliminary tests the two cell lines and HUVEC were characterized by cell ELISA in respect of the presence of the tight junction proteins occludin and zonula occludens protein-1 (ZO-1), the adhesion molecules ICAM-1 and VCAM-1 and the endothelial marker von Willebrand factor (vWF). Then, the influence of indometacin, lornoxicam and celecoxib on the expression of occludin, ZO-1, ICAM-1 and vWF of the two cell lines and HUVEC was analysed by cell ELISA. The COX inhibitors caused an effect on PBMEC/C1-2 and HUVEC but no influence was observed on ECV304. The results of PBMEC/C1-2 and HUVEC indicated that in comparable therapeutical concentrations celecoxib had a higher potential to impair endothelial cells and to decrease the expression of occludin, ZO-1 and ICAM-1 than indometacin and lornoxicam.

[A nursing intervention study in interdisciplinary cooperation: challenges and problem solving strategies]. / Durchführung einer Pflegeinterventionsstudie in interdisziplinärer Zusammenarbeit: Herausforderungen und Problemlösungsstrategien.

Doing a nursing intervention study in two hospitals in collaboration with physicians challenged all participating parties. The course of the study was influenced and partially changed by unforeseen problems. This article presents organizational perspectives on carrying through an intervention study while daily patient care is taking place and discusses specific issues of collaborating with physicians and nurses. Problem solving strategies and consequences from experiences with this study are presented.

Distribution of antibodies to porcine circovirus in swine populations of different breeding farms.

An enzyme linked immunosorbent assay (ELISA) was developed for mass antibody screening to porcine circovirus (PCV) in pig herds of different age groups and of different husbandries. Infection with PCV was found to be common in all swine herds tested, with only one exception, a herd at a small farm. Statistically, the percentage of PCV negative sera decreased and titer levels increased with increasing age of the pigs. Within individual age groups, differences were found to exist between different husbandries. No correlation was detected between antibody levels and reproductive disorders in the herds.