Our findings suggest that cognitively intact older men compared with women have higher resilience to pathophysiological processes of Alzheimer's disease.

No abstract

Khat chewing is deeply rooted in the every day life of people living in the Horn of Africa and in South Arabia, where Catha edulis is endemic. Considered little more than an exotic habit producing just mild pharmacological effects, systematic investigations on its active principles have instead lead to the isolation and chemical characterization of cathinone, a compound structurally related to amphetamine. Three decades of intense experimental and clinical research on khat have depicted a consistently clear picture of its pharmacological and toxicological effects.

3. Adenylyl(fl,y-methylene)diphosphonate (AMP-PCP) and AMP had no restituting effect, indicating that in order to act ATP must be hydrolysed.4. Na+-dependent Mg2+ outflow is not inhibited by vanadate concentrations that completely block the Ca2+ or Na+ pump. Therefore, the Nao-Mgi exchange does not fall into the class of cation pumps of the E1E2 type.5. Yet the fact that reversal of the Na+ gradient fails to reverse the direction of the Na+-dependent Mg2+ transport in human red cells (Lildi & Schatzmann, 1987) and that at equal Na+ concentration inside and outside the rate of Mg2+ transport is still 50 % of that at a Na+ concentration difference of -100 mm across the membrane suggests that the Na+ gradient, or the cation gradients in general, are not the only driving forces for Mg2+ movement. The assumption that there is energy input from ATP hydrolysis is compatible with these observations, whereas proposing the action of a protein kinase fails to explain them.6. It is concluded that the Na+-Mg + exchange system has an absolute requirement for ATP and that it is more probable that ATP is supplying energy for transport rather than activating transport by protein phosphorylation or simply by binding.

Oxidative stress (OS) is thought to play an important role in the pharmacological and toxic effects of various drugs of abuse. Herein we review the literature on the mechanisms responsible for the cardiovascular and hepatic toxicity of cocaine with special focus on OS-related mechanisms. We also review the preclinical and clinical literature concerning the putative therapeutic effects of OS modulators (such as N-acetylcysteine, superoxide dismutase mimetics, nitroxides and nitrones, NADPH oxidase inhibitors, xanthine oxidase inhibitors, and mitochondriotropic antioxidants) for the treatment of cocaine toxicity. We conclude that available OS modulators do not appear to have clinical efficacy.