If the plug-in named ChemScape Chime is properly installed on your computer, you should see a rotating 3D HIV-Tat molecule. The molecule can be moved by clicking it with the left button of your mouse and its characteristics, including automatic rotation, can be modified by clicking it with the right button.
To download the plug-in: 
.
KS lesion:
Kaposi's sarcoma (KS), whose frequency and aggressive behavior has been increasing in recent years in association with iatrogenic and acquired immunosuppression, is characterized by a prominent angiogenesis.
Angiogenic factors released by both KS and host
cells have been implicated in the pathogenesis of this lesion. The aim
of this study was to investigate the expression and role of thrombospondin-1
(TSP), a physiological inhibitor of
angiogenesis, in KS.
Immunohistochemical analysis of four KS lesions showed only spotty reactivity for TSP in the stroma and in <10% lesional blood vessels; also, the typical KS spindle cells were not stained. In agreement with these findings, lower amounts of TSP were measured with an ELISA assay in the supernatants of cultured KS cells compared to endothelial cells.
In vitro, TSP inhibited endothelial cell proliferation and motility induced by the supernatants of KS cells. TSP also prevented endothelial cell motility induced by Tat, a product of HIV-1 endowed with angiogenic potential and implicated in the pathogenesis of AIDS-KS.
In vivo, TSP inhibited the angiogenic activity exerted by Tat in the Matrigel sponge model.
These results suggest that TSP downregulation might be permissive for KS-associated angiogenesis.
J. Pathol. (1999) 188:76-81
