人脐静脉内皮细胞移植治疗角膜内皮功能衰竭的动物实验研究

目的：探讨异种脱细胞角膜基质为载体培养人脐静脉内皮细胞（HUVEC）进行后板层角膜移植（PLEK）治疗角膜内皮衰竭的可行性。方法：新西兰白兔30只,随机分为3组,实验组、基质组和对照组,每组10只,术中去除角膜内皮细胞,建立角膜内皮衰竭动物模型,实验组和基质组行后板层角膜移植术,对照组仅去除角膜后板层组织,不进行移植。术后观察3mo,对三组角膜的水肿混浊程度和中央角膜厚度进行统计学分析。结果：术后7d,实验组角膜水肿程度较基质组和对照组明显减轻,透明度增加。术后3mo时,实验组内皮细胞密度为2 026.4±129.3个/mm2,中央角膜厚度平均为505.2±25.4μm,基质组中央角膜厚度平均为1 535.6±114.5μm,而对照组为1 493.5±70.2μm。结论：实验以异种脱细胞角膜基质为载体培养人脐静脉内皮细胞,行后板层角膜移植术,治疗角膜内皮衰竭取得了初步成功。移植的人脐静脉内皮细胞能够在活体上成活,并具有一定的角膜内皮细胞的生物学功能,维持角膜透明,为临床上治疗角膜内皮疾病提供了新的思路和方法。     

Giant lamellar bodies as a feature of pulmonary low-grade MALT lymphomas

AIMS: Giant lamellar bodies (GLBs) are rare pulmonary inclusions, most frequently described in sclerosing haemangiomas. Following a recent report of their presence in a case of pulmonary lymphoma of MALT origin, our aims were to determine their frequency in pulmonary lymphoproliferative disorders, examine their structure and investigate their aetiology further. METHODS AND RESULTS: We reviewed a series of 29 pulmonary lymphomas (23 low-grade, six high-grade) and 18 cases of reactive pulmonary lymphoid hyperplasia. Five of 23 (22%) low-grade lymphomas contained GLBs, 4/4 of which stained for surfactant apoprotein A but not for surfactant apoprotein B. No GLBs were seen in 18 cases of reactive pulmonary lymphoid hyperplasia or six high-grade primary pulmonary lymphomas. Ultrastructural examination revealed concentrically arranged extracellular material forming roughly spherical structures up to 25 microm in diameter. The GLBs were often surrounded by foamy cells and cholesterol clefts, supporting an origin, at least in part, from products of cell breakdown and surfactant degradation. CONCLUSION: These findings support the idea that the presence of lamellar bodies is in part due to stasis of products arising from degradation of surfactant, in association with certain types of chronic pulmonary pathology. Given their absence in reactive pulmonary lymphoid hyperplasia, the presence of GLBs as an epiphenomenon in a pulmonary lymphoid infiltrate should warrant careful investigation with regard to the diagnosis of low-grade MALT lymphoma.     

选择性角膜内皮移植术

长期以来,治疗角膜内皮病变标准的方法为穿透性角膜移植术(PK)。虽然总体上说,PK手术成功率高,但由于术后视力恢复时间长,且可出现多种并发症,如高度散光／不规则散光、植片排斥反应以及与缝线和切口愈合相关的并发症等,因此并非一种理想的手术方式。过去十几年内,出现了多种选择性角膜内皮移植术,如经角膜瓣途径的内皮移植术、经角巩膜袋途径的内皮移植术及带活性内皮细胞的Descemet’s膜移植术等。与PK手术相比,这些新的手术方法理论：有着多方面的优势,初步的临床结果亦令人鼓舞,有可能成为替代传统PK手术治疗角膜内皮病变的更有效的方法。     

飞秒激光辅助的大气泡法深板层角膜移植治疗圆锥角膜

目的评价飞秒激光辅助的大气泡法深板层角膜移植术治疗圆锥角膜临床效果及安全性。方法系列病例研究。9例（11眼）圆锥角膜患者采用飞秒激光辅助进行大气泡法深板层角膜移植手术。供体及受体角膜均采用500 kHz VisuMax飞秒激光进行垂直边切,术前超声测量角膜最薄点厚度,角膜厚度为（359.7±49.8）μm,术前UCVA为指数～0.1,术前BCVA为指数～0.12,供体直径为（7.51±0.14）mm,受体直径为（7.38±0.10）mm,随访时间为（7.70±2.88）个月。结果所有患者手术顺利,术中无并发症,术后早期所有角膜植片透明。角膜厚度为（481.4±51.3）μm,角膜地形图恢复正常形态。术后最后1次随访,UCVA为0.15～0.40,BCVA为 0.30～0.80。结论飞秒激光辅助的大气泡法深板层角膜移植对于圆锥角膜患者具有良好的临床效果及安全性。     

医学工程技术人员在LASIK屈光手术中的重要性

在做LASIK手术时很多术者认为有一把好的角膜刀是非常重要的,其实还要有一支好的工程师队伍,这才是确保LASIK屈光手术成功的最基本条件。     

Reorganization of Lamellar Diblock Copolymer Poly(ε‐caprolactone)‐block‐poly(4‐vinylpyridine) in the Melting Temperature Range

The reorganization kinetics of the “original” lamellar diblock copolymer poly(ε‐caprolactone)‐block‐poly(4‐vinylpyridine) crystals formed at 260 K is studied in the melting region from 270 K (10 K below the onset of the melting peak of original crystals) to 310 K (the melting peak temperature) on the time scale starting from 10^?4 to 10² s by ultrafast differential scanning calorimetry. Different reorganization pathways are observed in this temperature range. Annealing at temperatures below 295 K leads to further stabilization of original crystals by secondary crystallization. At annealing temperatures higher than 295 K, crystals partially melt and the reorganization occurs via the melting–recrystallization. For even higher temperature, such as 310 K, the melting is completed within a few milliseconds and recrystallization starts from the nuclei formation. The sigmoidal recrystallization kinetics is analyzed by the Avrami equation. It is found that the copolymer experiences about one order of magnitude slower recrystallization rate and has higher melting peak temperatures of crystals formed after recrystallization than the homopolymer. The slower recrystallization kinetics in the copolymer is discussed from the viewpoint of the nanoscale spatial constraint and the intermediate state prior to the recrystallization.

     

Glaucoma after corneal replacement

Glaucoma is a well-known complication after corneal transplantation surgery. Traditional corneal transplantation surgery, specifically penetrating keratoplasty, has been slowly replaced by the advent of new corneal transplantation procedures: primarily lamellar keratoplasties. There has also been an emergence of keratoprosthesis implants for eyes that are high risk of failure with penetrating keratoplasty. Consequently, there are different rates of glaucoma, pathogenesis, and potential treatment in the form of medical, laser, or surgical therapy.     

Connectivity and Neuronal Synchrony during Seizures

There is uncertainty regarding when and which groups of neurons fire synchronously during seizures. While several studies found heterogeneous firing during seizures, others suggested synchronous neuronal firing in the seizure core. We tested whether neuronal activity during seizures is orderly in the direction of the excitatory neuronal connections in the circuit. There are strong excitatory connections laterally within the septotemporally organized lamella and inhibitory trans-lamellar connections in the hippocampus, which allow testing of the connectivity hypothesis. We further tested whether epileptogenesis enhances synchrony and antiseizure drug administration disrupts it. We recorded local field potentials from CA1 pyramidal neurons using a small microelectrode array and kindled rats by a rapid, recurrent hippocampal stimulation protocol. We compared cross-correlation, theta phase synchronization, entropy, and event synchronization. These analyses revealed that the firing pattern was correlated along the lamellar, but not the septotemporal, axis during evoked seizures. During kindling, neuronal synchrony increased along the lamellar axis, while synchrony along the septotemporal axis remained relatively low. Additionally, the theta phase distribution demonstrated that CA1 pyramidal cell firing became preferential for theta oscillation negative peak as kindling progressed in the lamellar direction but not in the trans-lamellar direction. Last, event synchronization demonstrated that neuronal firings along the lamellar axis were more synchronized than those along the septotemporal axis. There was a marked decrease in synchronization and phase preference after treatment with phenytoin and levetiracetam. The synchrony structure of CA1 pyramidal neurons during seizures and epileptogenesis depends on anatomic connectivity and plasticity.SIGNIFICANCE STATEMENT We could improve the efficacy of brain stimulation to treat seizures by understanding the structure of synchrony. Electrical stimulation may disrupt seizures by desynchronizing neurons, but there is an uncertainty on which groups of neurons fire synchronously or chaotically during seizures. Here, we demonstrate that neurons linked by excitatory connections fire synchronously during seizures, and this synchrony is modulated by epileptogenesis and antiseizure drugs. Closed-loop brain stimulation carefully targeted to disrupt synchrony may improve the treatment of seizures.