Epidermal growth factor prevents thallium(I)- and thallium(III)-mediated rat pheochromocytoma (PC12) cell apoptosis.

We have reported recently that the proliferation of PC12 cells exposed to micromolar concentrations of Tl(I) or Tl(III) has different outcomes, depending on the absence (EGF cells) or the presence (EGF cells) of epidermal growth factor (EGF) added to the media. In the current work, we investigated whether EGF supplementation could also modulate the extent of Tl(I)- or Tl(III)-induced cell apoptosis. Tl(I) and Tl(III) (25-100 μM) decreased cell viability in EGF but not in EGF cells.

Regulation of extracellular ATP in human erythrocytes infected with Plasmodium falciparum.

In human erythrocytes (h-RBCs) various stimuli induce increases in [cAMP] that trigger ATP release. The resulting pattern of extracellular ATP accumulation (ATPe kinetics) depends on both ATP release and ATPe degradation by ectoATPase activity. In this study we evaluated ATPe kinetics from primary cultures of h-RBCs infected with P.

Tl(I) and Tl(III) activate both mitochondrial and extrinsic pathways of apoptosis in rat pheochromocytoma (PC12) cells.

Thallium (Tl) is a highly toxic metal though yet its mechanisms are poorly understood. Previously, we demonstrated that rat pheochromocytoma (PC12) cells exposure to thallous (Tl(I)) or thallic (Tl(III)) cations leads to mitochondrial damage and reduced cell viability. In the present work we comparatively characterized the possible pathways involved in Tl(I)- and Tl(III)- (10-100 muM) mediated decrease in PC12 cells viability.

Thallium(III)-mediated changes in membrane physical properties and lipid oxidation affect cardiolipin-cytochrome c interactions.

Trivalent thallium (Tl(III)) is a highly toxic heavy metal through not completely understood mechanisms. Previously, we demonstrated that Tl(III) causes mitochondrial depolarization in PC12 cells leading to a decrease in cell viability. Given the role of the phospholipid cardiolipin (CL) in mitochondrial events, we evaluated in vitro the short- (2 min) and long- (60 min) time effects of Tl(III) (1-75 microM) on CL-containing membranes physical properties, and the consequences on cytochrome c binding to CL.

Relationship between thallium(I)-mediated plasma membrane fluidification and cell oxidants production in Jurkat T cells.

The effects of thallous cation (Tl(+)) on: (a) the production of oxidant species and (b) membrane fluidity were evaluated in human leukemia T cells (Jurkat). After 72 h of incubation in the presence of Tl(+) (5-100 microM), no significant changes in cell viability were observed, although the average cell size was decreased as evaluated by steady-state light scattering. Tl(+) (5-100 microM) caused a significant increase in the concentration of cellular oxidants as measured with the probe 5(6)-carboxy-2',7'-dichlorodihydrofluorescein diacetate (DCDCDHF).