Rosuvastatin regulates cerebral I/R damage to neurons by UCP2-SIRT3 signal / 中国临床药理学与治疗学

AIM: To study the protective effect and mechanism of rosuvastatin on cerebral ischemia-reperfusion injury. METHODS: (1) Cerebral infarction and OGD/R cell models were established to detect the effects of different concentrations of rosuvastatin on cell proliferation and apoptosis; (2) Different concentrations of rosuvastatin were used to treat OGD/R cell models and to observe rosuvastatin effects on cell morphology and expression and localization of UCP2-SIRT3 in cells; (3) UCP2 silent cell line was constructed to observe cell mitochondrial morphology and expression and localization of TOMM20 and SIRT3 molecules in cells, and to study the channels and mechanisms that play a protective role of rosuvastatin in OGD/R cell model; (4) The mitochondrial membrane potential, mitochondrial gene PGC1, Drp1 and Opa1 expression were detected to study the protective effect of rosuvastatin on mitochondria. RESULTS: (1) Rosuvastatin of different concentrations could significantly reduce OGD/R cell apoptosis and increase cell survival rate; (2) Rosuvastatin exerted cell protection by affecting the expression of UCP2 and SIRT3 in cells, thereby protecting cells from OGD/R injury; (3) Rosuvastatin affected the expression of TOMM20 by regulating UCP2, increased mitochondrial transmembrane transport and energy metabolism, enhanced mitochondrial function, and improved cell state and reduced apoptosis. CONCLUSION: Rosuvastatin inhibits mitochondrial damage of OGD/R cells by regulating UCP2/SIRT pathway, thereby exerting neuron protection.

Real-time volume rendering based on gradient adaptive shading / 南方医科大学学报

For medical image volume rendering, it is very difficult to simultaneously visualize interior and exterior structures while preserving clear shape cues. Highly transparent transfer functions produce cluttered images with many overlapping structures, while clipping techniques completely remove possibly important contextual information. To address this issue, A gradient adaptive shading based illumination model is proposed and implemented in CUDA architecture. The coefficients of ambient, diffuse and specular lighting are tuned adaptively according to gradient. The experiments show that our method is capable of preserving 3-D contextual information in medical image dataset while still show clear boundaries with real-time interactive speed.

Separation and purification of PEGylated rhG-CSF by two-step ion-exchange chromatography / 生物工程学报

In order to separate and purify the PEGylated recombinant human granulocyte stimulating factor (rhG-CSF) at large laboratory-scale level, a two-step ion-exchange chromatographic separation procedure was designed. Cation-exchange chromatography was applied first to separate PEGylated rhG-CSF from un-reacted rhG-CSF, followed by anion-exchange chromatography to dissolve individual PEG-rhG-CSF species (mono-, di- and tri-PEGylated rhG-CSF) and remove the free PEG. The molecular weight of individual PEGylated rhG-CSF was determined by MALDI-TOF and SDS-PAGE. MALDI-TOF mass spectrometry revealed that the molecular weights of mono-, di- and tri-PEGylated rhG-CSF are 23.8 kD, 28.6kD and 33.8kD, respectively. Cell proliferation activity was detected by MTT assay using NFS-60 cell. The in vitro residual bioactivity of mono-, di- and tri-PEGylated rhG-CSF were 90%, 75% and 43% respectively, comparing with the un-conjugated rhG-CSF. These results indicated that the un-conjugated rhG-CSF and excess free PEG can be removed completely and the three conjugate species can be purified into homogeneity by the two consecutive ion-exchange chromatographic steps. The purification procedure is easy to scale-up, high in performance and recovery.