脑红蛋白与高原眼底病

脑红蛋白(neuroglobin,Ngb)是最近研究发现的一类携氧球蛋白.在缺氧状态下能够促进氧气向线粒体内弥散,提高组织对氧的利用,尤其是在脑缺血缺氧性损伤时对神经组织有着非常重要的保护作用.已有研究证明Ngb在视网膜中的浓度约为脑中的50～100 倍,对其亦有重要的神经保护作用.高原眼底病是发生于高原低氧环境下的眼底疾病,低压性缺氧损伤是其主要改变.现我们就Ngb在高原眼底病方面的应用做一综述.     

高原红细胞增多症眼底改变的观察

目的：探讨高原红细胞增多症眼底改变。方法：对515例单纯型高原红细胞增多症患者采用直接眼底镜检查法进行了眼底观察。结果：515例单纯型高原红细胞增多症有眼底改变者456例(88．54％)，以视网膜静脉发绀、扩张、弯曲等改变为主。结论：视网膜静脉改变的程度与高原红细胞增多症的程度、病程以及在高原居住时间有关。     

眼底病临床研究的发展趋势

20世纪是眼底病研究的飞速发展期。与眼底病相关的基础和临床研究，其成果已不限于眼底疾病本身，甚至超出眼病的范围，为在生物医学这一更广阔的领域，揭示生命中最本质的规律提供了有用的信息。同时，借鉴于其他相关学科的新进展，眼底病诊断和治疗的实用技术得到了前所未有的发展，     

眼局部应用神经生长因子对视网膜的毒性研究

目的 兔眼局部应用不同剂量神经生长因子（NGF），观察NGF对视网膜的毒性作用。方法 健康灰兔42只，随机分为7组，每组6只。每只兔右眼结膜下或玻璃体内注射不同质量浓度的NGF 0.1ml，左眼注射生理盐水0.1ml作为对照。直接检眼镜检查：分别于注射前、注射后即刻、第1天和第7天观察视网膜情况。光镜及透射电镜检查：注药后第7天处死动物摘除眼球，光镜及透射电镜下观察视网膜情况。结果 直接检眼镜下均未发现眼底异常改变。光镜下，7组均未发现明显异常改变；透射电镜下只在第7组，即NGF 300μg/0.1ml玻璃体内注射组，发现视杆、视锥细胞盘膜内有裂隙，感光细胞内段的少部分线粒体嵴有损伤。结论 眼局部应用一般剂量NGF对兔眼视网膜无毒副作用。     

视网膜脱离术后使用神经生长因子的临床观察

目的:观察视网膜脱离术后使用神经生长因子的临床效果。方法:将32例视网膜脱离术后病例随机分为用药组和对照组。对照组术后给予皮质类固醇激素、银杏叶片及甲钴胺片口服,用药组在此基础上在给予神经生长因子肌注,比较两组的视力、视野及视觉诱发电位的改善情况。结果:用药组在视力、视野及视觉诱发电位的改善情况皆较对照组显著。结论:视网膜脱离术后使用神经生长因子有助于术后视功能的改善。     

神经生长因子及其受体与视神经视网膜疾病的研究进展

目前关于神经生长因子在视网膜视神经疾病中的作用研究很多 ,但观点很不一致。本文着重论述神经生长因子及其受体在视觉系统的分布、视神经损伤、缺血性视网膜疾病、视网膜变性疾病及增生性玻璃体视网膜疾病中的作用。     

大鼠视网膜脱离后神经生长因子及其受体的表达

视网膜脱离(retinal detachment,RD)术后视功能恢复不理想一直是眼科临床医师关注的重点.神经生长因子(nerve growth factor, NGF)是一类新发现的细胞因子,在神经损伤的保护过程中发挥着重要作用,被认为是最有希望的改善视功能的药物.本研究试通过对NGF及其受体TrkA 的研究,探讨NGF是否有可能用于RD以保护视功能.     

神经生长因子治疗视神经视网膜挫伤的探讨

目的 观察神经生长因子（NGF）治疗视神经视网膜挫伤的疗效。方法 48例（59眼）视神经视网膜挫伤患者,应用NGF和血管扩张剂治疗,此为治疗组。并以40例（49眼）仅用血管扩张剂和维生素治疗作为对照组。结果 在治疗组中,49眼痊愈,10眼显效。对照组中,16眼痊愈,28眼显效,两组间差异具有非常显著性意义。结论 NGF治疗视神经视网膜挫伤且有显著疗效。     

Nerve growth factor and corneal wound healing in dogs

Nerve growth factor in the tear film and corneal epithelium is hypothesized to play an important role in ocular surface maintenance and corneal wound healing. The purpose of this study was to determine the expression of nerve growth factor and its high affinity (trkA) receptor in tears, cornea, and lacrimal glands of normal dogs, the modulation of nerve growth factor and its trkA receptor during corneal wound healing, and the effect of topical nerve growth factor application on canine corneal epithelial wound healing. In the first of three experiments, the nerve growth factor content of tears, corneal epithelium, lacrimal gland, and 3rd eyelid gland was determined in normal dogs by enzyme-linked immunosorbent assay and the expression of nerve growth factor and its trkA receptor were evaluated in the cornea and lacrimal glands by immunohistochemistry. In a second experiment, unilateral corneal epithelial defects were created, and tissues were evaluated for changes in nerve growth factor or trkA expression for 1 week. In a third experiment, bilateral corneal epithelial defects were created and the right eyes in each animal were treated 4 times daily with either recombinant human nerve growth factor, murine nerve growth factor, or nerve growth factor-blocking antibody. The results of this study showed that nerve growth factor levels in normal dog tears, corneal epithelium, third eyelid gland and lacrimal gland were 15.4+/-4.6 ng ml(-1), 33.5+/-12.3, 52.4+/-17.4 and 48.8+/-9.4 ng g(-1), respectively. NGF and trkA receptors were identified by immunohistochemistry in all tissues examined. After unilateral corneal wounding, nerve growth factor concentration increased in the tears bilaterally for 3 days, especially in the wounded eye, and then returned to pre-wounding values. Nerve growth factor content, and immunohistochemical staining for nerve growth factor and trkA, increased significantly in the ipsilateral cornea epithelium following unilateral wounding. Nerve growth factor concentrations in lacrimal and third eyelid glands also increased bilaterally (p<0.01) after unilateral wounding. Time to wound closure and rate of epithelial migration did not differ significantly between nerve growth factor-treated, nerve growth factor antibody-treated, and control eyes. In conclusion, nerve growth factor is present under resting physiologic conditions in normal canine tears, and nerve growth factor and its trkA receptor are present under resting conditions in normal canine corneal epithelium, lacrimal gland and third eyelid gland. Nerve growth factor is elevated in the tears, cornea, and lacrimal glands after corneal epithelial wounding; however, topical application of nerve growth factor, or its blocking antibody does not modulate corneal wound healing in the normal dog eye.     

Nerve growth factor and eosinophils in inflamed juvenile conjunctival nevus

PURPOSE: To study both systemic and ocular nerve growth factor (NGF) in inflamed juvenile conjunctival nevus (IJCN), a benign, inflammatory juxtalimbal lesion characterized by many intralesional eosinophils, and to investigate the behavior of eosinophils cocultured on lesional and extralesional fibroblasts obtained from IJCN biopsies, in relation to NGF. METHODS: Eight patients with IJCN (7-15 years old) and six with noninflamed conjunctival compound nevus (12-30 years old) participated in the study. Conjunctival biopsy specimens were used for routine histology, immunohistochemistry (NGF, trkA, eosinophil cationic protein, and tryptase determination), in situ hybridization (NGF mRNA), and determination of fibroblast growth. Blood of patients with IJCN was used to measure NGF levels (by ELISA) and to isolate eosinophils (magnet activated cell sorter [MACS]). Eosinophils were seeded on lesional and extralesional fibroblasts and their adherence, survival (by trypan blue staining), and functional activity (by eosinophil peroxidase [EPO] assay) were assessed after 4 days. RESULTS: NGF in the blood of patients with IJCN and eosinophils and mast cells in their conjunctivas, were significantly elevated. NGF protein, NGF mRNA, and trkA were found to be increased in IJCN biopsy specimens compared with noninflamed compound nevi. Some NGF and trkA colocalized with eosinophils and mast cells. Lesional fibroblasts produced high amounts of NGF in comparison with extralesional fibroblasts and significantly enhanced eosinophil adherence, without influencing either their viability or activation. Adherence and EPO release were increased, in both lesional and extralesional fibroblasts. CONCLUSIONS: The triggering factors that lead to the prominent inflammation in IJCN are unknown. The data in the current study, showing the presence of increased NG-trkA, eosinophils, and mast cells in IJCN and the modulation of eosinophil properties by lesional fibroblasts partly through NGF, suggest a possible association between IJCN and allergic inflammation. Alternatively, this process may represent a direct immune response induced by the nevus itself.     

Ophthalmological effects of high altitude

High altitude has various effects on human beings. Altitude-related illnesses are a frequent cause of morbidity and occasional mortality in travelers to high altitudes throughout the world. The mountaineers all around the world are familiar with this condition, which is called acute mountain sickness (AMS). The primary altitude illnesses are AMS, high-altitude pulmonary edema and high-altitude cerebral edema. Altitude has potential undesired ophthalmological effects. The pathogenesis of these syndromes remains unclear despite considerable research in this field. Most of these problems are primarily preventable with an adequate level of information before and during travel. Further studies are needed to reveal the exact relationship between high altitude and ophthalmological findings. In this article, ophthalmological effects of high altitude, likely to be encountered by mountaineers as well as other enthusiasts of high altitude sports are reviewed. Emphasis on aviation and aerospace medicine is briefly given under related SUB_TITLEs.     

Corneal thickness at high altitude

PURPOSE: The eye, like other organs, is affected by the hypobaric hypoxia of high altitude. Corneal swelling is known to occur under hypoxic conditions at sea level, for instance when wearing contact lenses. The aim of this study was to measure central corneal thickness (CCT) in lowlanders ascending to altitude. METHODS: The Apex 2 medical research expedition provided the opportunity to measure CCT in 63 healthy lowlanders. The subjects arrived in La Paz, Bolivia (3700 m), where they spent 4 days acclimatizing before being driven over 2 hours to the Cosmic Physics Laboratory at Chacaltaya (5200 m), where they stayed for 7 days. CCT was measured in the early afternoon by using ultrasound pachymetry on the first, third, and seventh day at 5200 m and before and after the expedition at sea level. RESULTS: Mean CCT increased significantly from 543 microm at sea level to 561 microm on the first day at 5200 m (P < 0.001). This continued to increase to 563 microm on the third day and 571 microm on the seventh day but returned to 541 microm after descent to sea level. CONCLUSIONS: This study showed that altitude caused a significant increase in CCT in a large group of healthy lowlanders with normal corneas. This finding confirms the results of previous studies and is likely to be caused by endothelial dysfunction causing stromal swelling. This could potentially cause visual problems for high-altitude mountaineers among whom refractive surgery is popular.     

高原眼外伤发病情况的探讨

目的探讨高原眼外伤的特点,以便更好的防治。方法对7个月间住院的闭合性和开放性眼外伤107例,进行回顾性临床分析。结果高原眼外伤发生率高,眼外伤占同期住院总例数的50．95％;外伤伤情严重,治疗前视力低于0．05者占66．67％。致伤原因有其特殊性：就诊时间晚,最晚者伤后10d,平均（30．36±4．66）h;年龄偏小,平均年龄（30．80±1．33）岁,年龄最小者仅9个月;治疗后果差,治疗后视力低于0．05者仍占43．14％。结论应加强高原地区眼外伤防护知识及医疗技术支持。     

地域等因素对眼底病病种构成比的影响

目的:通过对我院801例与南方医院1000例眼底荧光血管造影(fundus fluorescence angiography,FFA)结果进行对比分析,探讨地域及其他各因素对眼底病病种构成比的影响。方法:将我院接受FFA患者资料801例与南方医院接受FFA患者资料1000例结果进行统计对比,并分析其原因。结果:视网膜血管阻塞性疾病、年龄相关性黄斑变性(agerelated macular degeneration,AMD)及糖尿病视网膜病变(diabetic retinopathy,DRP)患者数量我院明显大于南方医院,中心性浆液性脉络膜视网膜病变(central serous chorioretinopathy,CSC)患者数量南方医院明显大于我院。结论:由于我院就诊患者与南方医院就诊患者在生存环境、经济实力、饮食习惯、文化程度及就医依从性等存在差别,导致在眼底病种类及严重程度方面存在差异。