Ischemia/reperfusion injury and cardioprotective mechanisms:Role of mitochondria and reactive oxygen species

Reperfusion therapy must be applied as soon as possible to attenuate the ischemic insult of acute myocardial infarction(AMI).However reperfusion is responsible for additional myocardial damage,which likely involves opening of the mitochondrial permeability transition pore(mPTP).In reperfusion injury,mitochondrial damage is a determining factor in causing loss of cardiomyocyte function and viability.Major mechanisms of mitochondrial dysfunction include the long lasting opening of mPTPs and the oxidative stress resulting from formation of reactive oxygen species(ROS).Several signaling cardioprotective pathways are activated by stimuli such as preconditioning and postconditioning,obtained with brief intermittent ischemia or with pharmacological agents.These pathways converge on a common target,the mitochondria,to preserve their function after ischemia/reperfusion.The present review discusses the role of mitochondria in cardioprotection,especially the involvement of adenosine triphosphate-dependent potassium channels,ROS signaling,and the mPTP.Ischemic postconditioning has emerged as a new way to target the mitochondria,and to drastically reduce lethal reperfusion injury.Several clinical studies using ischemic postconditioning during angioplasty now support its protective effects,and an interesting alternative is pharmacological postconditioning.In fact ischemic postconditioning and the mPTP desensitizer,cyclosporine A,have been shown to induce comparable protection in AMI patients.

RAFT Copolymerization of Glycidyl Methacrylate and N,N-Dimethylaminoethyl Methacrylate

In this work, copolymerization of two functional monomers, glycidyl methacrylate （GMA） and N,N-dimethylaminoethyl methacrylate （DMAEMA）, was firstly carried out via reversible addition-fragmentation chain transfer （RAFT） polymerization successfully. The copolymerization kinetics was investigated under the molar ratio of n[GMA＋DMAEMA]o/n[AIBN]o/n[CPDN]o=300/1/3 at 60℃. The copolymerization showed typical ＂living＂ features such as first-order polymerization kinetics, linear increase of molecular weight with monomer conversion and narrow molecular weight distribution. The reactivity ratios of GMA and DMAEMA were calculated by the extended Kelen-Tudos linearization methods. The epoxy group of the copolymer PGMA-co-PDMAEMA remained intact under the conditions of RAFT copolymerization and could easily be post-modified by ethylenedia- mine. Moreover, the modified copolymer could be used as a gene carrier.

The potential link between PML NBs and ICP0 in regulating lytic and latent infection of HSV-1

Herpes simplex virus type 1(HSV-1)is a common hu-man pathogen causing cold sores and even more se-rious diseases.It can establish a latent stage in sensory ganglia after primary epithelial infections,and reacti-vate in response to stress or sunlight.Previous studies have demonstrated that viral immediate-early protein ICP0 plays a key role in regulating the balance between lytic and latent infection.Recently,It has been deter-mined that promyelocytic leukemia(PML)nuclear bod-ies(NBs),small nuclear sub-structures,contribute to the repression of HSV-1 infection in the absence of functional ICP0.In this review,we discuss the funda-mentals of the interaction between ICP0 and PML NBs,suggesting a potential link between PML NBs and ICP0 in regulating lytic and latent infection of HSV-1.

Primary nucleation of lithium carbonate

A set of laser apparatus was used to explore the induction period and the primary nucleation of lithium carbonate.Results show that the induction period increases with the decrease of supersaturation,temperature and stirring speed.Through the classical theory of primary nucleation,many important properties involved in primary nucleation under different conditions were obtained quantitatively,including the interfacial tension between solid and liquid,contact angle,critical nucleus size,critical nuleation free energy etc.