Brain Tumor Tropism of Transplanted Human Neural Stem Cells Is Induced by Vascular Endothelial Growth Factor

The transplantation of neural stem cells (NSCs) offers a new potential therapeutic approach as a cell-based delivery system for gene therapy in brain tumors. This is based on the unique capacity of NSCs to migrate throughout the brain and to target invading tumor cells. However, the signals controlling the targeted migration of transplanted NSCs are poorly defined. We analyzed the in vitro and in vivo effects of angiogenic growth factors and protein extracts from surgical specimens of brain tumor patients on NSC migration. Here, we demonstrate that vascular endothelial growth factor (VEGF) is able to induce a long-range attraction of transplanted human NSCs from distant sites in the adult brain. Our results indicate that tumor-upregulated VEGF and angiogenic-activated microvasculature are relevant guidance signals for NSC tropism toward brain tumors

Osmoregulatory capacity of the Cladocera.

Within the order Cladocera are found almost all varieties of osmotic regulation, which make it possible for them to live in waters of a wide range of salt concentrations. Many Cladocera are very powerful osmoregulators and are comparable to the teleosts and decapod crustaceans in their abilities. The variety of osmoregulatory capacities within the cladocerans are illustrated and discussed. The function of mitochondrion-rich ion transporting cells found in nuchal glands or on epipodites are diseussed and the physiological mechanisms involved in osmoregulation are compared with similar mechanisms in other crustaceans and in teleosts. Data is provided on osinotic regulation in eggs and embryos in open and elosed brood chambers. Other topics include the occurrence of physiological races in some species, recent changes in osmoregulatory abilities following man-induced changes in salinity, the effects of temperature on osmoregulation and the effects of pH