ABSTRACT
Vitreous is composed of transparent gel-like tissue with complex molecular structure,accounting for 80％ of the volume of the eyeball.In addition to support the eye structure,vitreous has important functions such as regulating eye development,refraction and cellular barriers,participating in intraocular oxygen metabolism and the development of retinal diseases.Age,myopia and systemic diseases and other factors have an impact on vitreous function.Intra-vitreous injection and vitreous surgery may interfere with vitreous function,damage the intraocular metabolic balance.To better maintain intraocular metabolic balance and visual function,it is important to study vitreous metabolic function carefully and intervene it cautiously.
ABSTRACT
Purpose To study the refractive state of silicone oil tamponade eyes. Methods To calculate the theoretical refractive state of eyes with silicone oil based on clinical visual optics and to perform retinoscopy on 48 silicone oil filled eyes with pars plana vitrectomy (PPV) and 45 ones with PPV plus lensectomy with retinal reposition, and then study theoretical and experimental differences of diopter in silicone oil filled eyes. Results Postoperative diopter of the former increases (+6.26?1.20) D than preoperative diopter, while that of the latter is (+11.40?2.22) D. Conclusion Hyperopic changes are found in silicone oil tamponade eyes, and the experimental values are lower than the theoretical ones. This may be helpful in predicting the change of diopter of silicone oil tamponade eyes.
ABSTRACT
Objective To investigate the effect of hypericin on the activity of protein kinase C (PKC) in cultured human retinal pigment epithelium (RPE) cells in vitro. Methods RPE cells were cultured in standard medium with 10% serum concentrations containing 0.5 to 5.0 ?mol/L hypericin with or without preincubation of phorbol 12 myristate 13 acetate (PMA). The activities of cytosolic PKC (c PKC) and membranous PKC (m PKC) were assayed by PKC kit. Results The original activities of c PKC and m PKC of RPE cells were (35.34?4.10) pmol?min 1 ?mg 1 and (62.52?8.80) pmol?min 1 ?mg 1 . The activity of c PKC in RPE cells with PMA preincubation decreased rapidly in 5 minutes, with a subsequent slow decrease after 20 minutes and a decrease to 18% of the activity of c PKC in RPE cells without PMA preinubation after 60 minutes. While the activity of m PKC in RPE cells with PMA preincubation increased gradually after 5 minutes and reduced after reached the peak at 40 minutes, and then returned to baseline after 60 minutes, eventually decreased below 30% of the control group. When RPE cells were cultured with PMA for 48 hours, the activities of c PKC and m PKC were hardly detectable, while RPE cells were cultured with both PMA and hypericin, hypericin could counteract most of down regulation by PMA. Conclusion Hypericin may inhibit the translocation of PKC in RPE cells,change the activity of PKC, promote the apoptosis of RPE cells likely,and then prevent proliferative vitreoretinopathy.