Fullfield electroretinalgraphy (ffERG) is an indispensablemeans in assessment of retinal disease; it is invasive, effective, objective, quantifiable, and reproducible. Currently ffERG has been extensively applied domestically, but it also has disadvantages such as too few detected diseases, nonstandardised methodology, and inaccurate description of the results. It is important to place more emphasis on the internationalization, standardisation, and normalization of the application; obtaining the differences of indication, detection techiniques, and description of the results among ffERG, multifocal ERG and pattern ERG; expanding the new fields and methods of clinical applications. So that ffERG could play an more important role in the diagnosis and management for the patients with retinal disease.
There are over 8 million blind patients in China, 1/3 of them are suffered from retinal degeneration diseases. Stem cells transplantation can delay the photoreceptor cell degeneration or replace the dead photoreceptor cells, provides hopes for these patients. How to make enough seed cells is the major barrier for cell therapy. Good seed cells should be safe and with great pluripotency, and can be made from a wide range of sources, easy to be standardized and industrialized. Seed cells made from three-dimensional embryonic stem cells cultures can reach the above criteria, thus three-dimensional embryonic stem cell culture is a new strategy for making seed cells for cell treatment of blind diseases.
Objective To observe the distribution and concentration of 125I-nerve growth factor (NGF) in rabbitsprime; eyes after intravitreal injection and posterior juxtascleral injection.Methods Intravitreal injection(group A) and posterior juxtascleral injection (group B) were performed with the dosage of 30mu;g/100mu;l 125I-NGF on left and right eyes in 45 white rabbits respectively. The gamma;-counts and the concentration of 125I-NGF (％ID/g) of each ocular tissue was determined 15 and 30 minutes, and 1,3,6,12,24,and 48 hours after injection. Results The 125I-NGF diffusion in group A was faster in ocular content and ocular inner wall. The vitreous content of 125I-NGF decreased gradually in group A, the curve changes in other eye tissues were normal. The concentration of 125I-NGF reached the peak 3 hours after injection in aqueous humor, iris and ciliary body, retina, and choroids, but 6 hours after injection in sclera and 8 hours in cornea. The changes of concentration of 125I-NGF in group B showed normal curve change. The peak time in group B were all 6 hours in all the tissues except aqueous humor (3 hours). Except the high concentration in vitreous body caused by intravitreal injection, the concentration of 125I-NGF in retina was the highest in group A. Conclusion Intravitreal injection of 125I-NGF can gain higher concentration in each ocular tissue than posterior juxtascleral injection, especially in retina. So intravitreal injection of NGF is a better ocular delivery method to treat the ocular fundus diseases.
Objective To describe cultured human retinal pigment epithelial (RPE) cells transdifferentiation and investigate the effects of human vitreous fluid on the morphologic and cytoskeleton changes of RPE cells in vitro. Methods Cytoskeleton characteristics in the 2nd, 5th, 8th passage of RPE cells in normal culture, which included cytokeratin 18 (CK18) and α-smooth muscle actin (α-SMA) were analyzed by Western blot. RPE cells were cultured in human vitreous-conditioned medium (VCM) at the concentration of 1∶4 for 6 days, morphologic changes were examined by light and electron microscopy, and cytoskeleton characteristics were analyzed by imunocytochemistry and Western blot. Results During culture in vitro, RPE cells lost epithelial characteristics and aquired fibroblast-like phenotype. The expression of CK18 was the highest at the 5th passage, and it decreased in the following passage, but α-SMA increased gradually. The morphologic transdifferentiation from epithelial to fibroblast-like cells of RPE was accelerated by VCM. Ultrastructural changes such as decreased microvilli and gradually increased rough endoplasmic reticulum and Golgi complex were found during the cultivation. CK18 produced by RPE cells decreased in VMC (P＜0.05), and α-SMA increased (P＜0.01). Conclusion Morphologic changes in epithelialmesenchymal transdifferenetiation of RPE cells are stimulated by VCM and accomplied by the shift of cytoskeleton proteins, The results imply that cells migration may be decreased and contraction may be enhanced in VCM. It may suggest that vitreous accelerates the pathogenesis of PVR and RPE cells play an important role. (Chin J Ocul Fundus Dis, 2002, 18: 289-292)
Purpose To identify the expression of alternatively spliced mRNA isoforms of the NMDA-R1 in the visual cortex of strabismic cats. Methods Two pai rs of normal and strabismic cats were used．The amblyopic cats had been made monocularly esotropic (by tenotomy) at the age of weeks，resulting in behavioral am blyopia．Animals were sacrificed about 6 months by intraperitoneal administration of Nembutal．Cryostat sections of fresh，frozen central visual cortex of the ats were cut to 20 micron thickness．A series of digoxygenin-labelled oligonucle otide probes basing on the human gene sequence were used for ISH．Control probes included sense oligonucleotides and short segment probes which were adjacent to ，but did not，span the splice junctions．A computer-assisted systematic morphometric ounting procedure was used to enumerate hybridising cells． Results The number of positive cells expressing NMDA-R1 mRNA in t he strabismic amblyopic cats was decreased，notably in layer IV of visual cortex (P＜0．0001)．The pattern of isoform expression varied between normal and strabismic amblyopic cats with decreased numbers of 1-a，1- b and 1-1 isoforms and apparently increased expression of 1-3 P ＜0．0001)，whereas no significant difference was found for the 1-2 and 1-4 isoforms (P＞0．05)． Conclusion Transcriptional inhibition of NMDA-R1 mRNA and of specifie isoforms may underlie the change in receptor expression．Alternatively，preferentialloss of neurones bearing particular NMDA-R1 isoforms and compensation with a proportional increase in cells expressing other isoforms may occurr during the critical period of visual plasticity． (Chin J Ocul Fundus Dis，2000，16：71-138)
Pattern-reversal electroretinograms(P-ERG)and visual evoked potential(P-VEP) were simultaneously recorded in 20 kittens reared with unilateral convergent strabismus,induced surgically at around 3 weeks after birth.P-VEP responses evoked through the normal and squint eyes consisted of two components at the initial stages,however changed systematically with age,and the second component of the squint eye disappesred earlier than that of the normal eye.P-ERG response for the variance in retinal function of squint eyes was more sensitive than the F-ERG.P-VEP responses from the squint eyes reduced significantly in amplitude as compared with those evoked through the normal eyes,even one week after surgery,while P-ERG responses unchanged and persisted through 30 weeks.Reduction of P-ERG amplitude of squint eyes developed about 6 weeks postnatal and the spatial resolution returned gradually at later stages.The results suggest that the strabismus may affect not only striate cortex,but also retina in developing kittens.In comparison with retinal deficits,cortical deficits may arise earlier and manifest more severe.
ObjectiveTo explore the distribution and features of the optic cup stem cells in embryonic rat at tailbud stage.MethodsThe distribution of optic cup stem cells in optic cup tissue in 12.5-embryonic-day-old rats was observed by immunohistochemistry. The separated cells from optic cup were cultured with serum-free media, and immunofluorescence technique was used to detect the ability of hyperplasia of stem cells and expression of CHX10 antigen and specific antigens of mature retinal cells before and after differentiation.ResultsThe optic cup stem cells in embryonic rat at tailbud stage were mainly located at inner, outer, and marginal layer of optic cup. No expression of specifically marked protein of mature retinal cells was detected. The cells separated from optic cup had the ability of single-cell clone, positive expression of CHX10 and expression of several specific antigens of mature retinal cells after the inducement, including Thy1.1, glial fibrillary acidic protein (GFAP), protein kinase C (PKC) α, and rhodopsin.ConclusionOptic cup of 12.5-embryonic-day-old rats composes of undifferentiated cells, and the stem cells are mainly located in optic cup inner and marginal. High ability of hyperplasia of the optic cup stem cells cultured in vitro is found. The cells, which are retinal stem cells, can express several specifically marked proteins of mature retinal cells after inducement and differentiation.(Chin J Ocul Fundus Dis, 2005,21:159-162)