Controlled release of photoswitch drugs by degradable polymer microspheres.

Background: QAQ (quaternary ammonium-azobenzene-quaternary ammonium) and DENAQ (diethylamine-azobenzene-quaternary ammonium) are synthetic photoswitch compounds that change conformation in response to light, altering current flow through voltage-gated ion channels in neurons. These compounds are drug candidates for restoring light sensitivity in degenerative blinding diseases, such as age-related macular degeneration (AMD).

Purpose: However, these photoswitch compounds are cleared from the eye within several days, they must be administered through repeated intravitreal injections.

CDK4-mediated MnSOD activation and mitochondrial homeostasis in radioadaptive protection.

Mammalian cells are able to sense environmental oxidative and genotoxic conditions such as the environmental low-dose ionizing radiation (LDIR) present naturally on the earth's surface. The stressed cells then can induce a so-called radioadaptive response with an enhanced cellular homeostasis and repair capacity against subsequent similar genotoxic conditions such as a high dose radiation. Manganese superoxide dismutase (MnSOD), a primary mitochondrial antioxidant in mammals, has long been known to play a crucial role in radioadaptive protection by detoxifying O2(•-) generated by mitochondrial oxidative phosphorylation.