The activities and distributions of succinate dehydrogenase(SDH),malic dehydrogenase(MDH),lactic dehydrogenase(LDH),acid phosphatase(ACP) and alkaline phosphatase(AKP) in retinal vessels were studied and observed with enzymatic histochemical techniques. The retinal vessels showed a b LDH activity, moderate SDH and MDH activity. The dehydrogenase activity described above was evenly and equally distributed in the microvasculature between arterioles and venules, and was the best in arteries. AKP showed predominant activity in the endothelial cells of capillaries and arterioles which were stained bly. No activity for ACP observed in the retinal vessels. The observations above indicate that the retinal vessels are metabolically active and have a great capacity for glycolysis. （Chin J Ocul Fundus Dis,1992,8:6-9）
目的 探讨视网膜微血管直径与2型糖尿病(DM2)并发症糖尿病视网膜病变(DR)的关系。 方法 选取2009年1月-11月住院确诊DM2患者200例，根据眼底彩色照相结果将患者分为DR组和NDR组，测量视网膜血管直径、测定生化指标及血压，用非条件Logistic回归分析糖尿病视网膜病变发生的危险因素。 结果 V1扩张10 μm时，DM2患者并发DR危险性增加(OR 1.75，95% CI 1.14～3.04，Plt;0.05)；空腹血糖水平增加1 mmol/L，DM2患者并发DR的危险性增加(OR 1.87，95% CI 1.43～2.81，Plt;0.05)； 糖化血红蛋白增加1个单位，DM2患者并发DR的危险性增加(OR 1.08，95% CI 1.02～1.13，Plt;0.05)；DM病程增加1年，DM2患者并发DR的危险性增加(OR 1.41，95% CI 1.18～1.70，Plt;0.05)。 结论 在DM2患者中，视网膜静脉直径大小、空腹血糖水平、糖化血红蛋白水平、糖尿病病程是DR发生的危险因素。
ObjectiveTo observe the effects of p21 activated kinase 4 (PAK4) on the mitochondrial function and biological behavior in retinal vascular endothelial cells. MethodsThe experimental study was divided into two parts: in vivo animal experiment and in vitro cell experiment. In vivo animal experiments: 12 healthy C57BL/6J male mice were randomly divided into normal control group and diabetes group, with 6 mice in each group. Diabetes mice were induced by streptozotocin to establish diabetes model. Eight weeks after modeling, quantitative real-time polymerase chain reaction and Western blots were performed to detect the expression of PAK4 in diabetic retinas. In vitro cell experiments: the human retinal microvascular endothelial cells (hRMEC) were divided into three groups: conventional cultured cells group (N group), empty vector transfected (Vector group); pcDNA-PAK4 eukaryotic expression plasmid transfected group (PAK4 group). WB and qPCR were used to detect transfection efficiency, while scratching assay, cell scratch test was used to detect cell migration in hRMEC of each group. In vitro white blood cell adhesion experiment combined with 4 ', 6-diamino-2-phenylindole staining was used to detect the number of white blood cells adhering to hRMEC in each group. The Seahorse XFe96 cell energy metabolism analyzer measures intracellular mitochondrial basal respiration, adenosine triphosphate (ATP) production, maximum respiration, and reserve respiration capacity. The t-test was used for comparison between the two groups. Single factor analysis of variance was used for comparison among the three groups. ResultsIn vivo animal experiments: compared with normal control group, the relative expression levels of PAK4 mRNA and protein in retina of diabetic mice were significantly increased, with statistical significance (t=25.372, 22.419, 25.372; P＜0.05). In vitro cell experiment: compared with the N group and Vector group, the PAK4 protein, mRNA relative expression and cell mobility in the hRMEC of PAK4 group were significantly increased, with statistical significance (F=36.821, 38.692, 29.421; P＜0.05). Flow cytometry showed that the adhesion number of leukocytes on hRMEC in PAK4 group was significantly increased, and the difference was statistically significant (F=39.649, P＜0.01). Mitochondrial pressure measurement results showed that the capacity of mitochondrial basic respiration, ATP production, maximum respiration and reserve respiration in hRMEC in PAK4 group was significantly decreased, with statistical significance (F=27.472, 22.315, 31.147, 27.472; P＜0.05). ConclusionOver-expression of PAK4 impairs mitochondrial function and significantly promotes leukocyte adhesion and migration in retinal vascular endothelial cells.
Objective To investigate the clinical characteristics of prepapillary and preretinal vascular loops. Methods The clinical manifestation, results of the fundus fluorescein angiography, and the prognosis of 20 cases(24 eyes) with prepapillary and preretinal vascual loops were analyzed retrospectively. Results 66.7% of prepapillary and preretinal vascular loops were involved in one eye, and 95.8% of vascular loops were located within one optic disc diameter. There were different configuration types of the vascular loops. Among 20 cases(24 eyes) of the vascular loops, 70.8%(17 eyes) were arterial, 12.5%(3 eyes) were venous, and 16.7%(4 eyes) were both arterial and venous. 62.5% of eyes with prepapillary and preretinal vascular loops were associated with other congenital and developmental anomalies of retinal vascular vessels. Conclusion Most PRVL are arterial and superior to the optic disc. The serious distortion of the vascular loops may result in disturbance of blood flow in artery and retinal hemorrhage, which cause visual loss. (Chin J Ocul Fundus Dis, 1999, 15: 9-11)
The existing retinal vessels segmentation algorithms have various problems that the end of main vessels are easy to break, and the central macula and the optic disc boundary are likely to be mistakenly segmented. To solve the above problems, a novel retinal vessels segmentation algorithm is proposed in this paper. The algorithm merged together vessels contour information and conditional generative adversarial nets. Firstly, non-uniform light removal and principal component analysis were used to process the fundus images. Therefore, it enhanced the contrast between the blood vessels and the background, and obtained the single-scale gray images with rich feature information. Secondly, the dense blocks integrated with the deep separable convolution with offset and squeeze-and-exception (SE) block were applied to the encoder and decoder to alleviate the gradient disappearance or explosion. Simultaneously, the network focused on the feature information of the learning target. Thirdly, the contour loss function was added to improve the identification ability of the blood vessels information and contour information of the network. Finally, experiments were carried out on the DRIVE and STARE datasets respectively. The value of area under the receiver operating characteristic reached 0.982 5 and 0.987 4, respectively, and the accuracy reached 0.967 7 and 0.975 6, respectively. Experimental results show that the algorithm can accurately distinguish contours and blood vessels, and reduce blood vessel rupture. The algorithm has certain application value in the diagnosis of clinical ophthalmic diseases.