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1.
Radioactively labelled iodoantipyrine has been used to measure optic nerve blood flow in experimental animals. The reliability of blood flow measurements with this technique may be limited by diffusion of tracer from the nearby choroid. The activity of tracer in the peripapillary choroid and anterior optic nerve was measured in a series of in vivo optic nerve blood flow experiments in cats. The diffusion of iodoantipyrine into cat optic nerve segments was also measured in vitro, and a model for diffusion of tracer from the peripapillary choroid into the anterior optic nerve was developed. The activity profiles established by simple diffusion experiments were similar to the activity profiles in the anterior optic nerve established by blood flow experiments. Apparent blood flow measurements in the anterior optic nerve made with iodoantipyrine may be largely influenced by tracer diffusion from the nearby choroid. For measurements of tracer activity which are statistically similar between control and experimental optic nerve samples, and with a total diffusion time of 60 sec (a well-done experiment), real blood flow in the experimental sample may differ by as much as 60% from the control at a point 50 micron from the choroid. At 300 micron from the choroid, the maximum undetectable difference because of diffusion declines to approx. 12%. These estimates assume an autoradiographic technique which can reliably detect tissue tracer activity differences of +/- 10%. Measurements of optic nerve blood flow made with diffusible tracers are affected by diffusion from the choroid and should be reported with estimated limits of reliability.  相似文献   

2.
BACKGROUND AND OBJECTIVE: The feasibility of an optical system for noninvasive imaging of chorioretinal oxygenation was evaluated. Due to its depth discrimination, this optical section imaging technique has potential for differential imaging of oxygen tension in the chorioretinal vasculatures. MATERIALS AND METHODS: The method consisted of projecting a narrow laser line obliquely on the retina after intravenous injection of an oxygen-sensitive probe and imaging the phosphorescence emission. Due to the angle between the incident laser and imaging path, a phosphorescence optical section image of the retina was captured. The phosphorescence intensity was measured in the chorioretinal vasculatures. The method was tested in three rats while breathing 10% oxygen, 50% oxygen, and room air. RESULTS: On the phosphorescence optical section image, vasculatures appeared laterally displaced according to their depth location, displaying probe phosphorescence separately in the chorioretinal vasculatures. Oxygenation increased in all vasculatures with increased inhaled percent oxygen. Oxygenation in the retinal artery was 2.3, 1.9, and 1.6 times oxygenation in the retinal vein, capillary, and choroid, respectively. During hypoxia, oxygenation decreased by 28%, 18%, 22%, and 14% in the retinal vein, artery, capillary, and choroid, respectively. During hyperoxia, oxygenation increased by 30%, 45%, 36%, and 28% in the retinal vein, artery, capillary, and choroid, respectively. CONCLUSION: The results demonstrate the feasibility of this technique for noninvasive and separate imaging of chorioretinal oxygenation and its potential for three-dimensional oxygen tension imaging.  相似文献   

3.
Latanoprost and matrix metalloproteinase-1 in human choroid organ cultures.   总被引:3,自引:0,他引:3  
PURPOSE: Latanoprost, a prostaglandin F2a analogue and ocular hypotensive agent, alters extracellular matrix and matrix metalloproteinases (MMPs), including MMP-1, within tissues of the uveoscleral outflow pathway. In addition to these tissues, the anterior choroid also is exposed to fluid within the uveoscleral outflow pathway. The present study was undertaken to compare MMP-1 expression in the choroid with other uveoscleral pathway tissues and to determine the effect of latanoprost on MMP-1 expression in human choroid organ cultures. METHODS: Choroid tissue explant cultures were generated and incubated with PhXA85, the biologically active form of latanoprost, or vehicle for 12 or 18 hours. Explant cultures from iris and ciliary body also were generated and exposed to PhXA85. Protein extracts of theses cultures, as well as from fresh tissues, were then probed for MMP-1 by Western blotting. All samples were normalized for protein content and reletive expression was evaluated by densitometry. Also, total RNA was harvested from fresh tissues or from cultures treated with PhXA85. The amount of MMP-1 mRNA in these samples was measured using real time polymerase chain reaction. These results were normalized according to simultaneous measurements of glyceraldehyde-3-phosphate dehydrogenase mRNA within the same samples. RESULTS: Compared to the ciliary body, in which specific MMP-1 concentration (/total mg protein) was greatest, the specific MMP-1 concentrations within iris, anterior choroid, and posterior choroid were less by 24.7 +/- 0.69%, 40.7 +/- 1.04%, and 64.5 +/- 0.52%, respectively (mean +/- SD). The order of MMP-1 mRNA expression among these tissues from fresh eyes was ciliary body < anterior choroid < posterior choroid < iris. Treatment of ciliary body explant cultures with 200 nM PhXA85 for 12 hours increased MMP-1 protein content by 154 +/- 34% (P = 0.004, students t test, N = 3). In contrast, similar treatment of anterior choroid, posterior choroid, or iris explant cultures minimally changed MMP-1 protein content (23 +/- 22+/-, P = 0.124; 14 +/- 8%, P = 0.462; 27 +/- 16%, P = 0.037, respectively). Increased MMP-1 was observed in choroid cultures incubated for 18 hrs with 200 nM or 500 nM PhXA85. MMP-1 mRNA in 12 hour PhXA85-treated choroid cultures was the same or less than vehicle-treated cultures from 7 of 9 donors. In contrast, MMP-1 mRNA was increased in PhXA85-treated ciliary body cultures from 2 of 2 donors. CONCLUSIONS: These results suggest that the capacity for latanoprost-mediated induction of MMP-1 within the choroid is less than within the ciliary muscle. Hence, it is unlikely that induction of MMP-1 in choroid plays as important a role in uveoscleral outflow modulation as induction of MMP-1 in the ciliary muscle.  相似文献   

4.
5.
PURPOSE: To develop a technique for noninvasive and real-time monitoring of chorioretinal temperature in transpupillary thermotherapy (TTT). METHOD: A modified slit lamp, which was equipped with two laser wavelengths (490 nm for illumination and fluorescein excitation and 810 nm for hyperthermia), was developed for TTT and temperature monitoring. Five types of liposomes were prepared, and their phase-transition temperatures were 40 degrees C, 46 degrees C, 47 degrees C, 48 degrees C, and 52 degrees C, respectively. Carboxyfluorescein was encapsulated in each liposome. After intravenous injection of each liposome, TTT with the modified slit lamp was performed on normal rat choroid or tissue with choroidal neovascularization (CNV). During TTT, chorioretinal temperature was monitored by observing release of fluorescein from circulating liposomes. RESULTS: Fluorescence from liposomes was initially observed around the heated lesion immediately after TTT began and disappeared rapidly when irradiation stopped. Choroidal and retinal temperatures were monitored separately. TTT for normal retina required higher power than that for normal choroid to observe fluorescence from a 40 degrees C, 46 degrees C, and 47 degrees C liposome. Retinal whitening was observed after TTT at a high-power setting. TTT for CNV required higher laser power than that for the normal choroid and retina. CONCLUSIONS: The results demonstrate the potential use of a noninvasive monitoring technique of chorioretinal temperature during TTT. The method should be useful to establish the TTT setting and achieve the optimal temperature increase in CNV.  相似文献   

6.
The peroxidase-antiperoxidase staining technique for the antigens S-100, neuron-specific enolase, and alpha 1-antichymotrypsin (alpha 1ACT) was applied to 57 intraocular tumors: 46 malignant melanomas of the uvea, seven retinoblastomas, and four tumors metastasizing to the eye. The staining characteristics of the different intraocular tumors were compared. Staining for S-100 in a fine-needle aspiration biopsy sample taken from a malignant melanoma of the choroid before enucleation of the globe was attempted. The positive staining of a few cells thus obtained suggested that this technique may be helpful in the diagnosis of melanomas. The alpha 1ACT stain used in this study has not been used previously in ophthalmology to our knowledge. We found 60% of malignant melanomas of the choroid stained positively. Another finding was the staining of the retinal pigment epithelium with alpha 1ACT in 30% of eyes with malignant melanoma of the uvea.  相似文献   

7.
实验性氩绿激光对视网膜脉络膜的损伤   总被引:2,自引:0,他引:2  
目的 :研究氩绿激光对视网膜脉络膜的损伤情况。方法 :4只成年有色兔 ( 8眼 )行眼底氩绿激光光凝 ,产生淡灰白几乎不可见的光凝斑 ,观察视网膜的病理光镜和电镜改变。结果 :激光前后 ,兔视网膜层未见明显损伤 ,但可见激光处的脉络膜毛细血管、小静脉轻度充血 ,无出血。结论 :轻度氩绿激光光凝视网膜不会损伤视网膜 ,但可引起脉络膜血管充血  相似文献   

8.
豚鼠形觉剥夺性近视眼视网膜、脉络膜多巴胺代谢的变化   总被引:3,自引:2,他引:1  
目的研究形觉剥夺对豚鼠神经视网膜、视网膜色素上皮(retinal pigment epithelium,RPE)/脉络膜复合体多巴胺(dopamine,DA)代谢的影响。方法28日龄豚鼠36只,分为3组:正常对照组、遮盖组、遮盖+去遮盖组,每组12只。遮盖组用半透明眼罩遮盖豚鼠右眼14d,遮盖+去遮盖纽在遮盖11d后去遮盖3d。14d后测定角膜曲率半径、眼球屈光度和眼轴长度。处死豚鼠,取眼后极部视网膜、脉络膜组织,用免疫组化染色和Western blotting法检测酪氨酸羟化酶(tyrosine hydroxylase,TH)蛋白在神经视网膜、RPE/脉络膜复合体的表达情况,用高效液相色谱检测神经视网膜、RPE/脉络膜复合体的DA、二羟基苯乙酸(3,4-dihydroxyphenylacetic acid,DOPAC)的含量。结果TH蛋白阳性表达于视网膜神经节细胞和内核层部分细胞,RPE/脉络膜复合体中表达阴性。遮盖14d后,豚鼠遮盖眼眼轴延长,近视形成,神经视网膜TH蛋白表达量和DA、DOPAC含量降低(P〈0.05)。遮盖+去遮盖纽的遮盖眼近视程度低于遮盖组.其神经视网膜TH蛋白表达量和DA、DOPAC含量升高(P〈O.05),但仍低于正常对照组(P〈O.05)。各纽豚鼠RPE/脉络膜复合体的DA、DOPAC含量比较,差异无统计学意义(P〉0.05)。结论形觉剥夺能调控豚鼠神经视网膜DA代谢,但不影响RPE/脉络膜复合体的DA代谢。  相似文献   

9.
apoB100 lipoprotein particles have been found to accumulate in Bruch membrane prior to the development of age-related macular degeneration (AMD). This work was performed to determine whether mice that overexpress apoB100 in the RPE/choroid and liver develop landmarks of early AMD over time. Mice transgenic for a human genomic fragment encoding the full length human apoB (“apoB100” mice) and litter-mate control mice were given a normal chow or high-fat diet for 12 months. Mice were evaluated for human apoB mRNA expression in the RPE/choroid and liver by RT-qPCR. Phenotypic changes associated with early AMD were evaluated by ultrastructural analysis using transmission electron microscopy. Changes were semi-quantified using linear regression analysis. Both the RPE/choroid and liver of apoB100 mice expressed both human and mouse apoB mRNA. Transmission electron microscopy showed ultrastructural changes consistent with early human AMD including loss of basal infoldings and accumulation of cytoplasmic vacuoles in the RPE, and basal laminar deposits containing long-spacing collagen and heterogeneous debris in Bruch membrane of apoB100 mice. In apoB100 mice given a high-fat diet, basal linear-like deposits were identified in 12-month-old mice. Linear regression analysis showed that the genotype (human apoB transgene) was a stronger influencing factor than high-fat diet in producing AMD-like lesions used in this study. Human apoB100 transgenic mice overexpress apoB in RPE and, with time, develop validated phenotypic changes that are seen in early human AMD. The phenotypic changes were aggravated by feeding a high-fat diet. The apoB100 mouse model could be valuable in determining the role of apoB-containing lipoproteins in triggering the onset of early AMD.  相似文献   

10.
ABSTRACT

Background: Gyrate atrophy of the choroid and retina is a rare autosomal recessive condition characterized by chorioretinal atrophy due to deficiency of the enzyme ornithine aminotransferase that can be complicated by intraretinal cystic spaces.

Case report: A 15-year-old female complaining of gradually progressive diminution of vision in both eyes preceded by night blindness was found to have gyrate atrophy of the choroid and retina with intraretinal cystic spaces that was evaluated using multimodal imaging including fluorescein angiography, optical coherence tomography, and optical coherence tomography angiography. Functional and anatomical improvement of the intraretinal cystic spaces was achieved with monthly intravitreal bevacizumab injections.

Conclusion: Repeated intravitreal bevacizumab injections can result in anatomical and functional improvement of intraretinal cystic spaces in patients with gyrate atrophy of the choroid and retina.  相似文献   

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