BackgroundRetinal pigment epithelial (RPE)cell senescence damage the metabolism of photoreceptor,leading to retinal dysfunction and loss of vision.To understand RPE cell senescence mechanism will contribute to the study of age-related macular degeneration ( AMD).ObjectiveThe present study was to prepare the ageing RPE cell model with passage and explore its potential mechanisms.MethodsThis study was approved by the Ethic Committee of Qingdao University Medical College,and the informed consent was obtained from each gravida.Six human eyeballs were obtained from artificial labor fetusl with the gestational age 16-28 weeks.RPE cells were isolated,cultured and passaged in vitro to establish the cell replicative aging model.The third to twelfth cells were collected to be used to this experiment.Human keratin was used to identify the cells by immunochemistry,and MTT method was utilized to assess the proliferation and viability of different generations of cells as the A490 value.The cellular cycles and transmembrane potential (△ψm)of mitochondrion (△ψm) with passage were detected and compared using Flow Cytometry. Results Cultured and passaged cells showed the hexagon in shape with the melanin in 1-2 generations of cells and presented with the brown staining in cytoplasm for human keratin.The melanin was absent in the third generation cells.Vibrant growth statues were seen from the 3-6 generations cells and thereafter the proliferation ability reduced.The cells of G0/G1 phase were gradually elevated with the passage from 3 - 12 generations with a percentage of 68.40％ in the third generation of cells to 87.33％ in the twelfth generation of cells,showing a significant difference among various generations ( F =180.43,P =0.00),and that of the sixth,ninth and twelfth generation of cells was significant higher than the third,sixth and ninth generation respectively (t =4.002,P＜0.05 ; t=12.885,P＜0.01 ;t=16.387,P＜0.01 ).MTT assay showed that of RPE cells were significantly declined with the passage ( F =38.77,P =0.00),and the A490 value of the ninth,twelfth generations of cells was considerably lower in comparison with sixth and ninth generation respectively ( t =5.991,11.983,P＜0.01 ).From 3 through 12 generations of cells,the staining intensity of rhodamine 123 was gradually decreased ( F =121.68,P =0.00 ),and the staining intensity in the sixth,ninth and twelfth generation of cells was significant lower than that the third,sixth and ninth generation respectively(t=6.918,7.620,11.207,P＜0.01 ).Conclusions A replicative aging model can be successfully created by the passage in vitro using human fetal RPE cells.The reduce of transmembrane potential and damage of mitochondria might be one of mechanisms of senescence of RPE cells.

Objective To study the protein conformational change of placenta tissue by using Raman spectrum.Methods By using Raman spectroanalysis,we detected the placenta protein conformational change of GDM and control groups.Results(1)In the placenta of GDM,the absorption bands of tryptophan and phenylalanine were increased obviously.(2)In the placenta of GDM,the secondary structure of protein was composed of α-helix,random coil and β-sheet.Conclusions In the placenta of GDM,the orderly conformations of main chains in protein are decreased.Side chains of amino acids,especially tryptophan and phenyl-alanine,are changed greatly.The structure variation of protein may be correlated to the diabetic complications.

polyhornal and round cells.Conclusion The AVN of rabbit was made up by different cells.The polyhornal and round cells may be pacemaker cells;the spindle cells might be transitional cells,and the triangle cells may be myocardial cells.

Background Increase in ophthalmic optical medical instruments and microsurgical applications leads to retinal photochemical damage and other problems delivery of a variety of devices,so the in-depth study and understanding of its pathogenesis after retina light damage can provide a reference for the clinical treatment of related diseases.Objective This study was to investigate the therapeutic effect and relative mechanism of erythropoietin (EPO) on mouse retina photic injury by studying the expression of matrix metalloproteinases-2 (MMP-2)and MMP-9.Methods Fifty-two SPF BALB/c mice were randomized into normal control group,simple light-induced group and EPO pretreatment group by balloting method.The mice of simple light-induced group and EPO pretreatment group were continuously irradiated with 6000 lx diffuse light for 4 hours in a home-made box to establish the models of light-induced damage;while recombinant human EPO (rhEPO)of 5000 U/kg was intraperitoneally injected prior to the light exposure in the EPO pretreatment group.The expressions of MMP-2 and MMP-9 were examined at 6,12,36,72,96 hours and 7 days following light-exposure by immunohistochemistry.Results Edema and structural disorder of RPE cells appeared inthe simple light-induced group after light-exposure and aggravated with lapse of light-exposure time,but no similar change was seen until 7 days in the EPO pretreatment group.The immunohistochemistry findings showed that the expression of MMP-2(A value)in RPE cells was less in the normal mice.However,a large quantity of positive cells appeared in RPE layer 36 hours after light-exposure.Compared with the simple light-induced group,the positive expression of MMP-2 protein in EPO pretreatment group was significantly decreased,showing statistically significant differences among these three groups and different time points (Fgroup =3.68,P =0 04; Ftime =9.13,P=0.00).There was hardly any MMP-9 expression in the retina of the normal mice.In simple light-induced group,a few of positive cells appeared in RPE layer 6 hours after light-exposure and reached its peak 12 hours following light-exposure.The gradually down-regulation of MMP-9 expression happened 96 hours later following light-irradiation.The expression tendency of MMP-9 in EPO pretreatment group was similar to the simple light-induced group.Significant differences in expressions of MMP-9 were found among different groups and time points (Fgroup=3.61,P =0.04;Ftime =16.91,P=0.00).Conclusions MMP-2 and MMP-9 may be involved in the mechanism of retina photic injury by down-regulating the expression of MMP-2 and MMP-9 in RPE cells.

Alcoholism ; therapy ; Humans ; Methanol ; poisoning

Humans ; Periapical Diseases ; therapy ; Periodontal Diseases ; therapy ; Tooth Crown ; injuries ; Tooth Diseases ; therapy ; Tooth Root ; injuries

Humans ; Tooth Crown ; pathology ; Tooth Diseases ; therapy ; Tooth Root ; pathology

Objective:To evaluate the ability of calcium hydroxide removal using different irrigation methods and the effect on canal sealing.Methods:200 human single root canal premolar teeth were prepared.Divided the teeth randomly into 2 groups(each group 96 teeth,8 as control),one group filled with chemical calcium hydroxide and another filled with finished product calcium hydroxide.7 days after,divided each groups randomly into 6 subsets and remove the calcium hydroxide in the root canal(table1).Then each subset group choose 8 teeth randomly,observed by scanning electron microscope.Other specimens were obturated by lateral condensation of cold gutta-percha with a AH-Plus sealer,stained by Indian ink and then made into transparent teeth model.Results:At the same condition,there was no significant difference between group A and group B;the results of groups associated with ultrasonic were better than groups with injection syringe.The rinse solution EDTA was the best,distilled water was the worse.Dye penetration showed that the length of dye staining was no significant difference among all groups.Conclusion:Ultrasonic and sodium hypochlorite associate EDTA is the best method to remove the calcium hydroxide.But none of the methods and rinse solution used in this experiment can remove all of the calcium hydroxide.The calcium hydroxide remained influence on the root canal sealer is not predominance.

Objctive To explore the relationship between the expression of Fas/FasL and the apoptosis occurs in retinal ischemia/reperfusion injury of rats, as well as the therapeutic effects of bFGF on the ischemic retina. Methods The models of retinal ischemia/reperfusion injury was made by transient elevating introcular pressure. A total of 28 rats were divided into normal and operation group.The latter were subdivided into 1 hour, 6, 12, 24, 48 and 72 hours after reperfusion group, in which the left eyes of the rats were in the ischemia/reperfusion groups and the right ones were in the treatment groups (bFGF intracameral injection). Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) method, and the expression of Fas and Fas ligand was studied by strept avidin-biotin complex (SABC)immunohistochemistry. Results No positive cells were observed in the normal rats′ retinae, but there was a significant number of TUNEL positive cells in 6-24 hours after transient ischemia followed by a decrease at the 48th hour. The number of TUNEL positive cells reached a maximum at the 24th hour after ischemia. The expression of Fas gradually increased as early as when it was at the 6th hour, reached a peak at the 24th hour, and then decreased at the 48th hour. Similarly, the expression of Fas ligand was at peak in 24-48 hours in GCL and INL of retina. Conclusions Retinal ischemia-reperfusion after transient elevated IOP induced apoptosis of cells in the retina. Fas/FasL may play an important role in the early events of the apoptotic pathways. bFGF can rescue RGCs from retinal ischemia/reperfusion injury through downregulation of the expression of Fas/FasL and may represent an important mechanism for therapeutic neuroprotection.

ObjectiveTo investigate the expression of hypoxia inducible factor 1 (HIF-1α) in rats' retinae during the embryonic and earlier postnatal period.MethodsThe retinal expression patterns of HIF-1α protein and mRNA of embryonic day 12 (E12), E16, E20, and postnatal day 1(P1) and P5 rats were determined by immunohistochemical staining and reverse transcription polymerase chain reaction (RT-PCR).ResultsHIF-1α protein was detected in the neural epithelial layer and the pigment epithelial layer at all those 5 timepoints, with higher expression in the ganglion cell layer and the inner plexiform layer, and seems limited to the ganglion cell layer when retina became more mature. Embryonic rat retina had higher expression of HIF-1α protein and mRNA than postnatal retina, the difference was significant (P<0. 01). ConclusionThe expression of HIF-1α in rats' retinae differs from embryonic to earlier postnatal stages.