GSK3β inhibits epithelial-mesenchymal transition via the Wnt/β-catenin and PI3K/Akt pathways

● AIM: To investigate the regulatory mechanism of glycogen synthase kinase 3β(GSK3β) in epithelialmesenchymal transition(EMT) process after proliferative vitreoretinopathy(PVR) induction. ● METHODS: Experimental PVR was induced by intravitreal injection of retinal pigment epithelium(RPE) cells in the eyes of rabbits. A PI3 K/Akt inhibitor(wortmannin) and a GSK3β inhibitor(Li Cl) were also injected at different time during PVR progress. Electroretinogram(ERG), ocular fundus photographs, and B-scan ultrasonography were used to observe the PVR progress. Western blot test on the extracted retina were performed at 1, 2, 4 wk. The expression of the mesenchymal marker vimentin was determined by immunohistochemistry. Toxicity of wortmannin and Li Cl were evaluated by ERG and Td Tmediated d UTP nick-end labeling(TUNEL) assay. The vitreous was also collected for metabolomic analysis.● RESULTS: Experimental PVR could significantly lead to EMT, along with the suppressed expression of GSK3β and the activation of Wnt/β-catenin and PI3 K/Akt pathways. It was verified that upregulating the expression of GSK3β could effectively inhibit EMT process by suppressing Wnt/β-catenin and PI3 K/Akt pathways. ● CONCLUSION: GSK3β effectively inhibits EMT via the Wnt/β-catenin and PI3 K/Akt pathways. GSK3β may be regarded as a promising target of experimental PVR inhibition.

Trocar opening: silicone oil removal with phacoemulsification and intraocular lens implantation

AIM: To evaluate the efficacy and safety of a modified technique [trocar opening(TO)] for silicone oil removal(SOR) in combination with phacoemulsification and intraocular lens(IOL) implantation.METHODS: A total of 60 eyes of 60 patients with cataract and silicone oil-filled eyes were enrolled in this study. The patients were divided into two groups: the patients in the control group underwent 23-gauge pars plana active SOR surgery with phacoemulsification and IOL implantation, while the patients in the TO group underwent TO methods during surgery. Best corrected visual acuity(BCVA), surgery time, intraocular pressure, and operative complications were observed 6 mo after surgery.RESULTS: There was no significant difference between the two groups in terms of age, gender, preoperative, intraocular pressure, or time of silicone oil stay. Prior to surgery, the mean BCVA for the control and TO groups was 1.34±0.44 and 1.36±0.42. At 6 mo following surgery, the mean BCVA improved to 0.74±0.36 and 0.77±0.32, respectively(P<0.001). There was no significant difference between the two groups. The mean SOR time was 6.9±2.3 min and 4.8±1.2 min in the control and TO groups(P=0.008). The total operation time was 28.2±8.5 min and 24.6±6.4 min, respectively(P=0.035). Posterior capsule rupture occurred in four eyes of control and none of TO group(P<0.01). Late recurrent retinal detachment occurred in one eye in the control group(2 mo after surgery) and in one eye in the TO group(4 mo after surgery). CONCLUSION: TO is a simple, effective, time-saving, and safe method for SOR combined with phacoemulsification and IOL implantation.

Survey of autonomous guidance methods for powered planetary landing

This paper summarizes the autonomous guidance methods(AGMs)for pinpoint soft landing on celestial surfaces.We first review the development of powered descent guidance methods,focusing on their contributions for dealing with constraints and enhancing computational efficiency.With the increasing demand for reusable launchers and more scientific returns from space exploration,pinpoint soft landing has become a basic requirement.Unlike the kilometer-level precision for previous activities,the position accuracy of future planetary landers is within tens of meters of a target respecting all constraints of velocity and attitude,which is a very difficult task and arouses renewed interest in AGMs.This paper states the generalized three-and six-degree-of-freedom optimization problems in the powered descent phase and compares the features of three typical scenarios,i.e.,the lunar,Mars,and Earth landing.On this basis,the paper details the characteristics and adaptability of AGMs by comparing aspects of analytical guidance methods,numerical optimization algorithms,and learning-based methods,and discusses the convexification treatment and solution strategies for non-convex problems.Three key issues related to AGM application,including physical feasibility,model accuracy,and real-time performance,are presented afterward for discussion.Many space organizations,such as those in the United States,China,France,Germany,and Japan,have also developed free-flying demonstrators to carry out related research.The guidance methods which have been tested on these demonstrators are briefly introduced at the end of the paper.