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Image segmentation is still a difficult problem since its effect would vary with the subjects processed. An approach of subtracting background from the entire image of retinal blood vessels presented in this paper. The background subtraction is based on the real image itself taken photographically and is not dependent on the prior knowledge of system for recording image, the approach achieves the grayscale enhancement of retinal blood vessels in preprocessing and provides a quality image for the next process of binarization. This experiment in the preprocessing of subtraction shows good enhancement effect.
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Humans , Algorithms , Artifacts , Fluorescein Angiography , Methods , Image Enhancement , Methods , Retinal VesselsABSTRACT
Although allograft corneal transplantation has made great progress,keratoprothesis implantation is the only one hope, for both the patients who has fleshy pannus corneal vitiligo and the patients with the failure corneal transplantation surgery whose far sight is only light perceptions to recover their eye sight. To gain success and reduce complications, a lot of work has been done in keratoprosthesis materials and type, but heterogeneity and bio-compatibility are not solved totally. Because of development in the cell culture and tissue engineering, cornea ex vivo culture has gain a critical success. From cell option to carrier using, reconstructed three dimensional culture and epithelium equivalent mimicked human corneas in key morphology and function and were used in basic and clinical investigation. This article reviews the development of materials of keratoprosthesis and tissue engineering cornea.
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AIM: In order to understand the pathological changes, characteristic of degeneration in optic nerve and retina after strike of optic nerve. METHODS: According to methods of Allen's spinal injury, a 600gcm-strike power was put on the intraocular portion of the optic nerve and created a striking injury on optic nerve. After a survival interval of 48 h, 1 week, 2 weeks, 4 weeks, 3 months, the animal's optic nerves and retinas were collected and fixed for morphological examination. RESULTS: Forty-eight hours after nerve injuries, the optic nerves were slight enlargement and vacuolation. In 1 week, the optic nerve began to degenerate in injured part and the glia cell had proliferated, but the forms of retinal ganglion cells(RGCs) were normal. In 2 weeks, the vacuolation and focal necrosis were appeared between nerve fiber. The number of RGCs began to decrease. Condensed nuclei presented in the retina. In three month, the diameter of the optic nerve decreased in injury part and collo-scar was formed. The phenomenon mentioned above was more obviously. The internal nuclear neurons and outer nuclear neurons appeared rare. The thickness of retina decreased. The number of RGCs began to decrease in 48 hours and progressed thereafter. It decreased about 3.35%, 13.23%, 19.74%, 23.20%, 29.28% in 48 h, 1 week, 2 weeks, 1 month, 3 months compared with the number of normal RGCs. RGCs began to apoptosis in 48 h. CONCLUSION: The model in this experiment could make definite uncompleted optic nerve and retina injuries. The degree of neuron injuries decreased from RGC, internal nuclear neurons to outer nuclear neurons. The number of RGCs began to decrease in 48 hours, and most quickly periods from 48 hours to one week.
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Objective To analyze the therapeutic effects of phacoemulsification with intraocular lens in several kinds of cataract.Methods The surgery was performed under topical anesthesia on 672 eyes of 546 patients with senile ,complicated ,congenital and traumatic cataracts through different incision.Results Postoperatively, the visual acuities with spherical correction or without correction were 0.5 or better in 83.0%, 88.9% of the eyes three hours later and in one day; and 1.0 or better in 27.2%, 28.7% in one week and one month. The mean postoperative astigmatism was all under +1.0D which was not found preoperatively in only 35 patients. There was no significant difference of the visual acuities between every two kinds of different cataract.Conclusion The phacoemulcification with intraocular lens implantation can be widely used in treating different kinds of cataract.
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OBJECTIVE:To study the change regular of esterase isozyme and peroxidase isozyme of Polyporus umbellatus. METHOD:Using polypropylene amide circle electrophoresis.RESULTS：The pattern and activity of isozyme in same strain had some difference at different culture days,but some of isozyme pattern bands of the Rf value were visible in whole culture stage.Every strain had its peculiar pattern bands.CONCLUSION:The number of isozyme pattern bands and enzyme activity were proportional to the growing rate of myceliun,as well as its metabolic activity.
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Process for the preparation of artificial seeds of Dendrobium candidum was established by using the somatic embryos of this plant. Experimental result showed that 1/2MS medium supplemented with sucrose was suitable to induce germination and seedling of D. candidum artificial seeds. The germination rate was over 80%.
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In the experimental study 5 cases of heteroepikeratophakia (HEP) (human to monkey) were done. The results showed that 4 HEP of experimental monkeys were found to be transparent in 6～24 months after operation. One of five experimental monkeys failed to have a transparent HEP because of epithelia implantation between donor lenticule and host cornea in the 3rd month after operation. In clinical study, HEP (monkey to human) was performed on 2 patients with aphakia. The visual acuity of these patients were improved because the transparent HEP was achieved. Either in experimental or in clinical study the immunological rejection was not found.
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AIM:To investigate the effects of rhTGF-?1 and TGF-?1 gene transfection on the proliferation of cultured rabbit corneal endothelial cells in vitro.METHODS:Cell growth induced by various concentrations of rhTGF-?1 was determined by MTT proliferation assay.Under the induction of liposomes,recombinant pSecTag2-TGF-?1MP vectors were transferred into the corneal endothelial cells.Morphological changes of transfected cells were observed by HE staining.The expression levels of TGF-?1 were assessed by ELISA.Cell cycle analysis was assessed by flow cytometry.DNA fragment analysis was used to confirm the presence of apoptosis.RESULTS:rhTGF-?1 in concentrations of 5-20 ?g/L showed a significant suppressive effect on the proliferation of corneal endothelial cells,0.5-1 ?g/L had no effect,0.05-0.1 ?g/L facilitated cell growth,as compared with negative controls.The morphous of transfected corneal cells had no significant abnormality compared with normal cells.According to the result of ELISA,the concentration of TGF-?1 in the supernatant was calculated to be(98?3)ng/L.Flow cytometry assay showed that S and G2/M phase of transfected cells decreased significantly compared with that of control group,but the cell cycle recovered normally after adding 10 ?g/L EGF into the culture medium.Agarose electrophoresis didn't show marked ladders in transfected group.CONCLUSION:Effects of rhTGF-?1 on the proliferation of corneal endothelial cells are different with various concentrations.TGF-?1 gene transfection shows suppressive effect on the proliferation of cultured corneal endothelial cells,but does not induce cell apoptosis.EGF is the antagonist of this suppressive effect.
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0.05). (2) In the total 12 rabbits, all the cornea grafts survived without rejection reaction, corneal haze or corneal neovascularization. The fresh grafts got transparent after 2 months, and the dehydrated grafts got transparent after 6 months. Histological study demonstrated both fresh and dehydrated stroma grafts had fused with rabbits'corneal stroma very well without lymphocytes infiltrating. (3) As shown in histological observations, the reconstructed cat corneal endothelial tissue was similar to the nature tissue. Cultured cat endothelial cells connected tightly to each other and attached to the Descemet's membrane closely. CONCLUSION: Swine corneal stroma has low immunogenicity and satisfying biocompatibility,it is an ideal biological carrier for cornea reconstruction in vitro.
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AIM: To investigate the influence of laminin (LN) on the expression of bcl-2 in rabbit cornea endothelial cells. METHODS: Cultured rabbit corneal endothelial cells were divided into three groups: normal control group, LN group and negative control group. Immunohistochemical technique and ELISA were used to measure the staining and A value to assess the levels of bcl-2 expression. RESULTS: Bcl-2 expression score showed that LN group had a strong positive expression. Control group only showed a weak expression. Negative control group showed a negative expression by immunohistochemical staining. The mean A value of each group were 1.21?0.18 (LN group), 1.05?0.14 (normal control group) and 0.04?0.01 (negative control group). CONCLUSION: LN promotes bcl-2 gene expression in rabbit cornea endothelial cells, and protects the cells from apoptosis.
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AIM: In order to search carrier material and better tissue culture method, the morphology and structure of the cultured cat corneal endothelium was observed. METHODS: The cat corneal endothelial cells were seeded on the Descemet's membrane of the dehydrated swine corneal stroma, and then cultured in the medium with epidermal growth factor and laminin for 7 days. The morphology and structure of reconstructed tissue was tested by the inverted microscope and the scanning electron microscope. RESULTS: As shown by the morphological observations, the cultured cat corneal endothelial cells formed an integrated membrane, and attached to the Descemet's membrane, which was similar to the nature tissue. The cells connected tightly to each other, and some of them arranged in hexagon approximately. CONCLUSION: The cat corneal endothelial cells could be rebuilt on the carrier of the dehydrated swine corneal stroma successfully, which is similar to the nature tissue.
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AIM: To observe the immunoregulation of all ogeneic cornea on the human peripheral blood T lymphocytes in vitro. METHODS: After Co-culture of human peripheral blood lymphocytes and allogeneic cornea in vitro, T lymphocytes were labeled by monoclonal ant ibody, and analyzed by fluorescent activated cell sorter (FACS). RESULTS: CD25 expression on T lymphocytes in control was 25.2%, after stimulated by the allogeneic cornea or PDB, CD25 expression on T lymphocy tes was 56.8% and 80.9%, respectively. After stimulated by the allogeneic corn ea, CD25 expression on CD 4+ or CD 8+ T lymphocytes were 67.3% and 52.3% , respectively. CONCLUSION: Allageneic cornea stimulates CD25 expression on huma n peripheral blood T lymphocytes, and the CD25 expression on CD 4+ T lymphocy tes is more prominent than CD 8+ T lymphocytes.
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0.05), the expression of CD4+ was increased in rabbit corneal stroma (P