后极性白内障超声乳化吸除及折叠型人工晶状体植入术的临床观察

目的：探讨小切口超声乳化治疗后极性白内障的手术技术以及术中、术后并发症的处理方法。方法：46例患者(61只眼)，年龄38-78岁，平均57岁。在表麻下行颈侧透明角膜隧道切口的超声乳化，并对后囊下混浊斑块行剥离吸除、环形撕后囊或剪除混浊的后囊及折叠型人工晶状体植入术。结果：51只眼后囊膜完整，其中6只眼有后囊膜混浊；在10只后囊膜破裂眼中，4只眼有玻璃体脱出需行前段玻璃体切割术，并有1只眼晶状体皮质软壳沉入玻璃体腔引起葡萄膜炎及继发性青光眼需再次行后段玻璃体切割。58只眼人工晶状体囊袋内固定，3只眼睫状沟固定。结论：对后极性白内障行超声乳化手术时，谨慎处理后囊下混浊斑块，可以减少术中、术后的并发症，明显提高患者的术后视力。眼科学报2003；19：92-94     

Endogenous fungal endophthalmitis: risk factors, clinical course, and visual outcome in 13 patients

AIM:To analyze the risk factors,ophthalmological features,treatment modalities and their effect on the visual outcome in patients with endogenous fungal endophthalmitis(EFE).METHODS:Data retrieved from the medical files included age at presentation to the uveitis clinic,gender,ocular symptoms and their duration before presentation,history of fever,eye affected,anatomical diagnosis and laboratory evidence of fungal infection.Medical therapy recorded included systemic antifungal therapy and its duration,use of intravitreal antifungal agents and use of oral/intravitreal steroids.Surgical procedures and the data of ophthalmologic examination at presentation and at last follow-up were also collected.RESULTS:Included were 13 patients(20 eyes,mean age 58 y).Ten patients presented after gastrointestinal or urological interventions and two presented after organ transplantation.In one patient,there was no history of previous intervention.Diagnostic vitrectomy was performed in 16 eyes(80%)and vitreous cultures were positive in 10 of the vitrectomized eyes(62.5%).In only 4 patients(31%),blood cultures were positive.All patients received systemic antifungal therapy.Sixteen eyes(80%)received intravitreal antifungal agent with voriconazole being the most commonly used.Visual acuity(VA)improved from 0.9±0.9 at initial exam to 0.5±0.8 logMAR at last followup(P=0.03).A trend of greater visual improvement was noted in favor of eyes treated with oral steroids(±intravitreal dexamethasone)than eyes that were not treated with steroids.The most common complication was maculopathy.Twelve eyes(60%)showed no ocular complications.CONCLUSION:High index of suspicion in patients with inciting risk factors is essential because of the low yield of blood cultures and the good general condition of patients at presentation.Visual prognosis is improved with the prompt institution of systemic and intravitreal pharmacotherapy and the immediate surgical intervention.Oral±local steroids could be considered in cases of prolonged or marked inflammatory responses in order to hasten control of inflammation and limit ocular complications.     

阻抗成像中恒流驱动模式的研究

在电阻抗成像中,当测量系统精度一定时,驱动模式直接决定了原始数据的信息量和信噪比,并影响成像质量.目前主要有相邻、交叉、相对驱动模式,这三种模式的电流驱动角不同而电压测量方式相同.在此基础上扩展为统一驱动模式,各种驱动角下数据的格式是一致的,有助于电阻抗成像技术的应用和交流.对不同驱动角的性能进行理论分析和实验验证,表明驱动角的增大会减小测量电压的波动,有利于小目标成像;驱动角为3个电极左右时,有利于多个目标的分离.     

后肢去负荷对大鼠比目鱼肌肌梭神经末梢的影响

目的观察后肢去负荷对大鼠比目鱼肌肌梭神经末梢形态的影响。方法采用大鼠尾部悬吊法建立后肢去负荷动物模型，按体重配对原则随机将大鼠分为5组，即后肢去负荷7d组、14d组、21d组、28d组和正常同步对照组。分离单一肌梭，采用快速的银染方法，光镜下对肌梭的形态及其神经末梢进行观察并拍照。结果正常对照组大鼠比目鱼肌肌梭形态完整，包囊光滑，边缘清晰，赤道部和两极部神经末梢清晰完整，梭内肌横纹亦清晰可见；后肢去负荷7d后肌梭神经末梢与对照组相比未见明显异常；后肢去负荷14d后肌梭赤道部神经纤维淡染，末梢出现轻微的溶解，断裂；后肢去负荷21d后肌梭内神经末梢密度明显减少，肌梭赤道部神经纤维断裂，溶解；后肢去负荷28d后肌梭神经末梢呈严重的退行性改变，出现断裂，迂曲。结论后肢去负荷可引起肌梭赤道部与极部神经末梢的退行性改变，且随去负荷时间的延长而加重。     

Iterative phasing for fluctuation X-ray scattering

Fluctuation X-ray scattering (FXS) is an extension of small- and wide-angle X-ray scattering in which the X-ray snapshots are taken below rotational diffusion times. This technique, performed using a free electron laser or ultrabright synchrotron source, provides significantly more experimental information compared with traditional solution scattering methods. We develop a multitiered iterative phasing algorithm to determine the underlying structure of the scattering object from FXS data.X-ray solution scattering of macromolecular complexes is a versatile technique, providing low-resolution structural information that, when supplemented with high-resolution crystallographic data, can result in fundamental insights into the physiological behavior and function of macromolecular machines (1). Although solution scattering has been applied successfully to many problems in the biological sciences (2, 3), the technique suffers from a significant shortcoming. Due to the 3D averaging that occurs during the X-ray snapshots, the effective information content of the data is typically only around 9–15 independent parameters (4). This lack of sufficient information in the data ultimately results in nonunique or poorly determined structural hypotheses.To overcome these issues, it was proposed to perform the solution scattering process at timescales below rotational diffusion times (5, 6). By avoiding physical rotational averaging, speckle patterns emerge from which angular correlation functions can be computed. These so-called fluctuation X-ray scattering experiments can be performed on modern synchrotrons (7) and free electron laser sources (8, 9). The angular correlation information provided from these experiments is directly related to the imaged structure (10) and contains significantly more information than standard small- and wide-angle X-ray scattering (SAXS/WAXS) data. Although the relation from real space structure to fluctuation scattering data is straightforward, the inverse problem of determining a molecular model from fluctuation scattering data is nontrivial (8).For 2D systems, such as macromolecules randomly oriented around a single axis (11), an analytical route for image reconstruction is available (12). However, this approach requires triple correlation measurements across the full resolution range of interest, which may not be fully accessible due to experimental limitations.Earlier work attempting to determine 3D shape from fluctuation scattering data was based on solving two phase problems consecutively. Although this route has shown success in cases where the scattering species has helical (13) or icosahedral symmetry (14), it fails to produce a structure for the general case. Another approach was developed in which the inverse problem was solved using a reverse Monte Carlo method (8), similar to what is used to determine macromolecular envelopes from SAXS data (15–17). Although this approach allows a real space object to be reconstructed without the need for symmetry constraints, the procedure is computationally expensive and, in general, convergence can be problematic (18). Furthermore, the existing reverse Monte Carlo method assumes a binary model, where voxels either have a scattering length or do not. The breakdown of this uniform density assumption ultimately limits the resolution of features that can be reconstructed through such an approach.Here we develop a fundamentally different approach to structure solution from fluctuation scattering, based on a multitiered iterative phasing (MTIP) algorithm. In particular, we derive a series of projection operators, which are used to iteratively modify a model to satisfy specified real space constraints and match the derived model fluctuation scattering data to external observations. This approach does not require a uniform density assumption and solves the two inherent phase problems concurrently, which allows one to obtain a reconstruction with a reduced amount of fluctuation scattering data, or even SAXS/WAXS data alone, by compensating with the extra information provided through real space constraints.The presented method allows one to study the structure of objects that cannot be easily crystallized, while achieving higher resolution than what is possible through standard SAXS/WAXS experiments. As a result, this approach can be used to gain deeper insight into biological structure and to expand the range of characterization methods for nanostructures (19). Furthermore, the framework developed here allows one to extend many of the density modification techniques developed for crystallography to solution scattering.     

Effect of surface properties on the antithrombogenicity of silk fibroin/S-carboxymethyl kerateine blend films

Polymeric blends of silk fibroin (SF) and S-carboxymethyl kerateine (SCMK) were prepared by the solvent casting method to study the effect of surface properties on the antithrombogenicity. The films of SF/SCMK showed better antithrombogenic properties than SF or SCMK alone. Among them, the film containing 50 wt% SCMK showed the best antithrombogenicity. When the SF/SCMK films were treated with methanol, the antithrombogenicity of the films was scarcely affected except the SF-rich ones. The enhanced antithrombogenic properties were explained in terms of polarity of the surface. The blend films showed an enhancement of polar contribution to surface free energy (γ_S ^P) and polar stabilization energy (I_sw). SF-rich films showed high γ^P _S and I_sw values when treated with methanol. This change of surface properties was considered to be due to the fact that the conformational transition from random coil structure to β-structure of proteins may have affected the surface properties, especially the polar properties.     

Posterior polar cataract: Hydrodissection and nucleus rotation in manual small-incision cataract surgery not a taboo with proper fluidics

A posterior polar cataract is a discoid posterior polar plaque-like cataract with a thin and fragile to absent posterior capsule with adherent acellular opacity to the capsule reported in the literature. It is a stationary or slowly progressive opacity. A higher risk of complications such as posterior capsular tear and nucleus drop makes this a challenging surgery. The techniques described in the literature include bimanual irrigation aspiration, leaving the plaque for later Yag, bimanual micro phaco, Lambda technique with dry aspiration, Phaco if opacity <4 mm and soft nucleus, pars plana vitrectomy (PPV), pars plana lensectomy (PPL) if opacity >4 mm and soft nucleus, intra-capsular cataract extraction (ICCE) and scleral fixated intraocular lens (IOL) if opacity >4 mm with the hard nucleus, viscodissection, 3 ports PPL, PPV, low parameters phaco, modified epinucleus removal, inverse horse-shoe technique, standard phacoemulsification, chip and flip for soft cataracts, stop and chop for hard cataracts, layer-by-layer phacoemulsification, standard lens aspiration, pars plicata posterior vitrecto-rhexis, manual small-incision cataract surgery, and conventional extracapsular extraction. A posterior capsule rupture rate of 0 to 36% is reported in different series for cataract extraction. To prevent this dreaded complication, surgeons used many modifications. Minimal hydrodissection in posterior polar cataract extraction was described by Fine et al. The authors describe a technique of low flow manual small-incision cataract surgery with minimal hydrodissection and nucleus rotation with no associated posterior capsule rent. This demonstrates that if the fluidics is understood and corrected, then minimal hydrodissection and nucleus rotation is not taboo in posterior polar cataract extraction by manual small-incision cataract surgery.     

金雀异黄素对雌性小鼠卵母细胞成熟及其受精能力的影响

目的:探讨金雀异黄素(Gen)对小鼠卵母细胞成熟的影响.方法:用不同浓度的Gen给小鼠腹腔注射后,检测Gen对卵母细胞生发泡破裂(GVBD)、第一极体(PB1)释放、体外受精和胚胎发育等的影响;用含不同浓度的Gen的培养液培养小鼠未成熟卵母细胞,观察卵母细胞GVBD、PB1释放的发生率;结果:腹腔注射Gen可以增加小鼠子宫湿重,增加小鼠的超排卵数(除高剂量组外)、影响卵母细胞体内成熟过程中的GVBD和第一极体的释放(Gen-0.5组除外),高剂量组小鼠成熟卵母细胞的受精能力和胚胎发育能力均下降.Gen以剂量依赖的方式抑制体外培养小鼠未成熟卵母细胞的GVBD和PB1的释放.结论:Gen能够可逆性地抑制小鼠未成熟卵母细胞的成熟,高剂量的Gen可能影响卵母细胞减数分裂过程,降低卵母细胞的受精能力,提示育龄妇女摄人过量Gen及其化合物可能会导致生育能力降低,甚至造成不育或不孕.     

OCT及视野极性分析图检测对早期慢性青光眼诊断价值

目的 应用光学相干断层扫描技术（OCT）及视野极性分析图,检测慢性青光眼视网膜神经纤维层（RNFL）厚度和视野缺损情况,分析两者的相关性及其在早期慢性青光眼诊断中的价值。方法 采用海德堡Spectralis OCT对42例（62只眼）青光眼（包括15例原发性开角型青光眼和27例慢性闭角型青光眼）病人颞上方、鼻上方、颞侧、鼻侧、颞下方、鼻下方RNFL厚度进行测量,计算RNFL出现缺损的阳性率,OCTOPUS 900全自动视野计进行视野检查,采用极性分析图观察相应区域有无视野缺损,并计算其阳性率。结果 OCT检测早期慢性青光眼病人颞上方、鼻上方、颞侧、鼻侧、颞下方、鼻下方RNFL损伤阳性率分别为54.8%、29.0%、30.6%、29.0%、54.8%、30.6%,其中颞上方和颞下方RNFL缺损的阳性率较高（χ^2=21.96,P〈0.001）;而极性分析图检测各象限视野缺损阳性率分别为96.8%、64.5%、91.9%、30.1%、98.3%、61.2%,颞上方和颞下方阳性率较高（χ^2=28.35,P〈0.001）,与OCT检查结果具有较好的一致性,两种检测方法颞上方、鼻上方、颞侧、颞下方及鼻下方阳性率比较差异有显著性（χ^2=14.08～26.10,P〈0.001）。OCT及视野极性分析图均表现出鼻侧阳性率较低,且两者的阳性率相比差异无显著性（P＞0.05）。结论 视野极性分析图检测视野缺损与OCT检测RNFL变化具有较好的一致性,极性分析图是评估与随访青光眼病人RNFL结构与功能的桥梁,可能为临床早期诊断青光眼提供更多的信息。