Effect of intravitreal dexamethasone on ocular histopathology in a rabbit model of endophthalmitis

The histologic and clinical effect of intravitreal dexamethasone was studied in a rabbit model of experimentally induced gentamicin sensitive Staphylococcal epidermidis endophthalmitis. The study compared four treatment groups: vitrectomy alone (group I), vitrectomy plus intravitreal gentamicin (group II), vitrectomy plus intravitreal gentamicin and dexamethasone (group III), and intravitreal gentamicin and dexamethasone without vitrectomy (group IV). All eyes treated with dexamethasone, with or without vitrectomy, exhibited less clinical and histologic manifestations of inflammation. This study suggests that suppression of inflammation through the use of intravitreal dexamethasone leads to preservation of ocular architecture with potentially improved retinal function and visual benefit.     

Inflammatory response in experimental Staphylococcus and Pseudomonas endophthalmitis.

Staphylococcus epidermidis [2.0 x 10(4) colony-forming units (CFU)/0. 1 ml] and Pseudomonas aeruginosa (2.0 x 10(3) CFU/ml) were inoculated in the vitreous humor of rabbits. In S. epidermidis endophthalmitis, the numbers of microorganisms reached a maximum (4. 1 x 10(7) CFU/ml) at day 2 after inoculation and then declined spontaneously. However, clinical scores were observed to be worst at day 5. In P. aeruginosa endophthalmitis, the numbers of microorganisms reached a maximum (9.3 x 10(6) CFU/ml) 36 h after inoculation. However, culture results were persistently positive until day 15. Electroretinogram (ERG) b-wave amplitudes in S. epidermidis endophthalmitis continued to decrease from day 3 (>24%) until day 5, and then recovered to the preinoculative level of amplitudes at day 7. ERG b-wave amplitudes in P. aeruginosa endophthalmitis continued to decrease after 24 h (>24%). ERG b-wave amplitudes from day 7 to day 15 were flat. The inflammatory response continued under the absence of microorganisms in S. epidermidis endophthalmitis. The time in which a maximum in the number of microorganisms was reached was earlier than that in the clinical examination scores in both S. epidermidis and P. aeruginosa endophthalmitis.     

Immune response to Staphylococcus aureus endophthalmitis in a rabbit model

Staphylococcus aureus is an important cause of severe bacterial endophthalmitis. Both immunoglobulin (Ig) G and A antibody titers to ribitol teichoic acid (RTA), the major antigenic determinant of the S. aureus cell wall, were measured by an enzyme-linked immunosorbent assay in serum, tears, aqueous, and vitreous on days 3, 7, 10, 14, 21, and 30 after intravitreal injection of viable S. aureus in rabbits. Clinical examination showed vitreous opacification in all rabbits from days 7-30. Histopathologic examination showed acute inflammation on day 3 and chronic inflammation on days 7-30 in the conjunctiva, cornea, iris, ciliary body, and trabecular meshwork. The vitreous cavity contained neutrophils and necrotic cells on all days. Retinal necrosis was present on days 14-30. Lymphoid follicles with plasma cells were identified in the conjunctiva, ciliary body, and choroid. The vitreous of experimental eyes showed increasing numbers of bacteria from days 3-14, followed by a decrease in numbers on day 21 and absence of viable bacteria on day 30. Increases in IgG antibody levels to RTA were first detected in serum where they were higher than in tears, aqueous, and vitreous until day 14. Vitreous IgG antibody levels to RTA in experimental eyes exceeded all other samples on day 14 and progressively increased thereafter; the other samples declined. The IgA antibody levels were increased in tears on day 14 and in the vitreous of experimental eyes on days 14, 21, and 30. Vitreous IgG antibody levels to RTA were substantially higher than vitreous IgA antibody levels. An inverse correlation was found between vitreous IgG antibody levels and positive vitreous cultures, suggesting that the humoral immune response may be important in the spontaneous sterilization of the vitreous in this model.     

金黄色葡萄球菌眼内炎模型的建立及实验室诊断

目的 建立外源性金黄色葡萄球菌性眼内炎动物模型。方法 新西兰种大耳白兔24只，分为空白对照组及3个实验组，后者分别于眼内注入不同浓度的金黄色葡萄球菌。又分为高浓度组(10^4CFU／mL)，中浓度组(10^3CFU／mL)和低浓度组(10^2CFU／mL)。结果 (1)3组术后均有不同程度炎症反应，术后24小时～3天角膜浑浊，前房渗出或积脓；3．7天炎症反应开始减轻；10～14天玻璃体呈灰白色浑浊。(2)细菌培养于术后12～24小时阳性率最高，3组分别为100％、100％、33％；术后3天阳性率明显下降，7～10天阳性率为0％。(3)病理学变化：术后1～12小时虹膜和睫状体充血，眼内炎性细胞浸润；术后24小时视网膜下渗出和视网膜脱离；术后3～7天为全眼球炎。结论 成功建立金黄色葡萄球菌眼内炎动物模型；确立了实验室诊断方法。     

Immune response to Staphylococcus epidermidis-induced endophthalmitis in a rabbit model.

Although Staphylococcus epidermidis is the most common cause of postoperative pseudophakic endophthalmitis, little is known about the immune response to S. epidermidis-induced endophthalmitis. Using a rabbit model, the immune response to an intravitreal injection of 7000 S. epidermidis (group 1) or 30,000 S. epidermidis (group 2) organisms was investigated. Clinical evaluations showed that rabbits in group 2 had a more severe inflammatory reaction in the conjunctiva, cornea, iris, and vitreous than those in group 1. The inflammatory reaction in group 1 largely resolved by day 30; group 2 continued to show a severe inflammatory response. Histopathologic findings correlated with clinical findings, with rabbits in group 2 showing a more severe inflammatory reaction in both the anterior and posterior segments of the globe. Positive vitreous cultures for S. epidermidis were present in rabbits in group 1 on days 3, 7, 10, 14, and 21 but not thereafter. However, group 2 had higher vitreous colony counts at days 3, 7, and 14 and negative vitreous cultures thereafter. Neither group showed delayed hypersensitivity to S. epidermidis antigens (evaluated by skin tests). Serum immunoglobulin (Ig) G antibody levels to phenol-inactivated S. epidermidis and glycerol teichoic acid (GTA) increased progressively, reached a peak at days 10-14, and then declined in both groups. Serum IgA antibody levels to these antigens were not detected. Group 2 had a more prolonged IgG antibody response in vitreous and aqueous than group 1. Tear fluid showed the weakest IgG and IgA antibody response to S. epidermidis and GTA. S. epidermidis-induced endophthalmitis was associated with a humoral but not a delayed hypersensitivity response to this organism.     

白内障超声乳化联合人工晶状体植入术后霉菌性眼内炎

目的:探讨白内障术后霉菌性眼内炎的发病过程及临床表现,希望有助于临床医师对该疾病的认识。方法:回顾性分析近年来我院5例白内障超声乳化联合人工晶状体植入术后发生霉菌性眼内炎的发病经过、临床表现、诊断治疗及预后等情况。5例于白内障术后30～50d确诊眼内炎后均急诊行前房冲洗、玻璃体切除硅油填充术。并于玻璃体切除术后局部及全身使用抗真菌类药物。结果:有2例行眼内容剜除术,3例术后3mo随访见眼球轻度萎缩,视力分别为光感和指数/眼前。结论:对内眼手术即使是眼前节手术术后迟发型眼内炎症反应或经正规抗生素、激素治疗病情反复者应想到有真菌感染的可能,及时抽取标本作细菌、真菌涂片、培养及药物敏感试验,争取能够早期诊断和治疗,最大限度保留有用视力和眼球。     

晶状体过敏性眼内炎的氧自由基机制

目的 探讨晶状体过敏性眼内炎（ＰｈＥ）的发病机制。方法 采用顺磁共振技术,检测实验性ＰｈＥ大鼠眼局部组织氧自由基与超氧化物歧化酶（Ｃｕ．Ｚｎ－ＳＯＤ）水平。结果 ＰｈＥ发病时氧自由基显著自升高,此后逐渐降低;而Ｃｕ．Ｚｎ－ＳＯＤ的变化与之相反。这些变化与眼组织炎症反应及病理变化基本一致。结论氧基可能是导致ＰｈＥ早期炎症和病理损害的重要介质。     

细菌性眼内炎的免疫赦免及免疫应答机制

细菌性眼内炎是能导致视力严重受损的眼科重症,即使采取了及时和积极的药物及手术干预,仍会造成眼部组织不可逆的损伤.对细菌性眼内炎的研究热点是研究眼部组织对感染的免疫反应及病原微生物和宿主组织间分子和细胞的相互作用.目前国内外对细菌性眼内炎免疫应答机制的研究包括免疫赦免、固有免疫反应、补体系统、Fas配体、炎性细胞浸润、细胞因子及细胞间黏附因子的作用等方面.     

STZ诱导的糖尿病大鼠晶状体中解耦联蛋白、MnSOD表达的变化

目的研究大鼠晶状体中解耦联蛋白(UCPs)异构体的表达类型,及UCPs、MnSOD mRNA表达随糖尿病病程的变化,探讨糖尿病白内障发病的相关机制。方法以链脲佐菌素(STZ)尾静脉注射建立糖尿病大鼠模型,在模型建立后2、4、8及12周分别摘出大鼠的晶状体,RT-PCR法检测UCP1-55种异构体以及MnSOD的mRNA表达量。结果在正常大鼠晶状体中只表达UCP2。糖尿病模型建立12周时有8/15只(53.3%)大鼠发生糖尿病白内障,16周时有7/9只(77.8%)大鼠发生糖尿病白内障。UCP2、MnSOD mRNA表达随病程而变化,2周时表达量升高,之后二者表达均下降,至12周时降至正常水平。结论大鼠晶状体表达UCP2异构体,UCP2及MnSOD mRNA表达量的逐渐减少与糖尿病白内障的发病有关。     

Inflammatory response, endophthalmitis, corneal dystrophy, glaucoma, retinal detachment, dislocation, refractive error, lens removal, and enucleation.

This paper provides a synopis of published data on most of the major complications of the implantation of currently used intraocular lenses. With one exception, these studies lack controls, and the results show the variations expected when a variety of lens implants, techniques, and surgeons are compared. The author's personal data are also included.     

Alterations of lens metabolism with experimentally induced cataract in rats

Rat lenses with experimentally induced cataract (either by naphthalene or by streptozotocin) were analyzed biochemically. Both noxae had some effects in common. Water-soluble protein and aldose reductase activity decreased, and glucose-6-phosphate dehydrogenase, phosphofructokinase and glutathione reductase activity increased. A specific effect of streptozotocin was the rise in glucose, fructose and sorbitol. A specific effect of naphthalene was increased amounts of water-insoluble protein.     

Nocardia endophthalmitis following uncomplicated phacoemulsification and implantation of a posterior chamber intraocular lens

A patient developed endophthalmitis 15 days after uncomplicated cataract extraction. Excised infectious material sequestered in the capsular bag revealed Nocardia on culture. She required multiple intravitreal injections of Amikacin and dexamethasone, pars plana vitrectomies with explantation of the lens, and chronic topical and oral sulfonamide antibiotics to control the infection. Clinicians should also consider Nocardia when the suspicion of fungal endophthalmitis is entertained, as Nocardia are resistant to antifungals, but respond to intravitreal amikacin and chronic topical and oral sulfonamides.     

Clinical assessment of ocular response to a multipurpose contact lens care solution

The issue of possible adverse effects of contact lens care solutions on ocular health has been raised in the literature. Possible effects of a multipurpose contact lens care solution (Bausch & Lomb ReNu®) on eight measures of ocular function were evaluated relative to the effects of physiological saline (Bausch & Lomb Sensitive Eyes®). In a randomized, two-treatment, crossover design, all subjects were treated with each of the two solutions on successive weeks. In 73 subjects, comprised of contact lens and non-lens wearers, tear break-up time was measured using the keratometer mire and fluorescein techniques. Measures of autonomic function were vertical palpebral aperture size, amplitude of accommodation, intraocular pressure, pupil size, conjunctival injection, and pupil reactivity. The results indicated that this multipurpose solution provoked no adverse ocular response as determined by the tear break-up time and autonomic functions, and the multipurpose solution was clinically equivalent to physiological saline. These results apply to both contact lens wearers and non-lens wearers. Additional findings speak of the unreliability of the fluorescein method for measuring tear break-up time.