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No description available.

No description available.

No description available.

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No description available.

As gene therapy and other macromolecular medicines become more important in the treatment of cancer and other diseases, the need for more appropriate in vitro assays in which to test them also increases. At present, complex genetic treatments are often tested in vitro on monolayer cultures or single cell suspensions, which are vastly different in both physical and, sometimes, genetic characteristics from their in vivo situation. This means that many therapeutics have to be tested in animals or humans before problems with their delivery are discovered. This study aimed to characterise three dimensional (3-D) in vitro models of tumour cells and assess their usefulness at representing the in vivo situation more accurately in vitro.

Homotypic and heterotypic cell interactions are critical in the assembly and maturation of blood vessels. The aim of this study was to determine the role of Angiopoietin-1 in controlling interaction between endothelial cells and mural cells, and define the classes of molecules involved in mediating this interaction. The influence of heterotypic cell interaction on expression of activin receptor-like kinase 1 (ALK-1) was examined in order to gain insight into the mechanisms of mural cell control of endothelial phenotype. In addition, to begin to explore cell-cell interaction in vessel assembly in vivo attempts were made to establish a non-invasive model for inducing neovessel formation.;Angiopoietin-1 was found to stimulate adhesion between endothelial cells and smooth muscle cells by more than two-fold. This adhesion was calcium-dependent and inclusion RGD-peptides decreased adhesion by 70%, and decreased the effect of Angiopoietin-1 by 66%. Blockade of neural-cadherin (N-cadherin) with cyclic-HAV peptides decreased heterotypic adhesion between endothelial cells and mural cells by 30%. N-cad was found to localise strongly to junctions between smooth muscle cells and homotypic adhesion between these cells was inhibited by inclusion of N-cad-blocking peptides. Previous work suggested ALK-1 expression was modulated by endothelial cell-mural cell contact. No evidence was found for contact-induced changes in expression of ALK-1 under the conditions of this study. An in vivo model for augmenting microvessel number was established in patients with peripheral vascular disease by local application of subcontractile electrical stimulation.;These studies define a direct role for Angiopoietin-1 in control of heterotypic interaction between cells of the vessel wall and show involvement of both integrins and N-cadherin in this interaction. The non-invasive model for increasing neovessel density could be useful for examining capillary stabilisation in vivo in future studies.

No description available.

Prototypic foamy virus (PFV)-based vectors are currently made by transient transfection. Continuous vector production by cells in which PFV proteins are stably led would allow rapid, reproducible generation of large quantities of vector. Previous attempts at constructing packaging cell lines have resulted in very low titre production. Here, we utilise a method described to generate a stable HIV-1 producing cell-line in an attempt to produce high titres of PFV vector. PFV gag-pol or env genes were stably transduced into a variety of cell lines using an MLV-based delivery system. The resultant cell lines were positive for stable DNA integration and for high levels of protein expression, and produced between 10³ and 10⁵ infectious units of PFV vector. However the cells gradually reduced protein production which finally ceased completely after 4-5 weeks, possibly due to cytotoxicity.