Synthesis of seleno- and thio-guanine-Pt (II) complexes and their antitumor activity in mice

Selenoguanine- and selenoguanosine-platinum(II) complexes were synthesized, and their atitumor activities against L1210 in mice and against in vitro tissue culture system were studied. These compounds exhibited antitumor activity of medium strength and showed very low toxicity. The effect of the SeG-Pt (II) complex in mice was retained longer than that of the parent compound SeG because the SeG-Pt (II) complex very slowly released SeG into blood.     

Non-fibrillar amyloid-β peptide reduces NMDA-induced neurotoxicity, but not AMPA-induced neurotoxicity

Amyloid-β peptide (Aβ) is thought to be linked to the pathogenesis of Alzheimer’s disease. Recent studies suggest that Aβ has important physiological roles in addition to its pathological roles. We recently demonstrated that Aβ42 protects hippocampal neurons from glutamate-induced neurotoxicity, but the relationship between Aβ42 assemblies and their neuroprotective effects remains largely unknown. In this study, we prepared non-fibrillar and fibrillar Aβ42 based on the results of the thioflavin T assay, Western blot analysis, and atomic force microscopy, and examined the effects of non-fibrillar and fibrillar Aβ42 on glutamate-induced neurotoxicity. Non-fibrillar Aβ42, but not fibrillar Aβ42, protected hippocampal neurons from glutamate-induced neurotoxicity. Furthermore, non-fibrillar Aβ42 decreased both neurotoxicity and increases in the intracellular Ca²⁺ concentration induced by N-methyl-d-aspartate (NMDA), but not by α-amino-3-hydrozy-5-methyl-4-isoxazole propionic acid (AMPA). Our results suggest that non-fibrillar Aβ42 protects hippocampal neurons from glutamate-induced neurotoxicity through regulation of the NMDA receptor.