Ultrastructural Study of Lichen Planus:

ABSTRACT: Colloid bodies, which are eosinophilic, dyskeratotic, damaged epidermal cells that show signs of fibrinoid necrosis and premature keratinization, may play a rote in the pathogenesis of lichen planus. An ultrastructural study of two patients with lichen planus focusing on the colloid bodies suggests the possibility of these bodies initiating the lichenoid dermal reaction.     

Transient retinal artery occlusion during phacoemulsification cataract surgery

Purpose

Transient retinal artery occlusion (TRAO) is a potentially underdiagnosed cause of immediate ‘pad off'' visual loss following phacoemulsification cataract surgery under sub-Tenon''s anaesthesia.

Methods

We describe a series of three patients presenting with enigmatic ‘pad off'' visual loss following phacoemulsification surgery, each diagnosed with TRAO. We describe the variable clinical presentation, illustrate the value of optical coherence tomography (OCT) imaging in establishing the diagnosis, and present the final visual outcomes.

Results

Clinical findings alone may be subtle and inadequate in localising the pathology in patients with TRAO. Cross-comparison of superior and inferior macula OCT profiles in branch-pattern arterial occlusion—and between healthy and affected eyes in central-pattern arteriolar occlusion—is critical in clinching the diagnosis. The typical evolution of OCT appearance is acute-phase inner retinal thickening/oedema and hyperreflectivity followed by progressive, late-phase inner retinal atrophy. Visual acuity may recover but central scotomas, and defects in colour perception may persist.

Conclusion

The diagnosis of TRAO is challenging; delayed presentation may resolve fundal and retinal angiographic abnormalities. OCT may be the only imaging modality that can provide objective evidence of TRAO. Meticulous comparison/segmentation of OCT images is therefore mandatory in patients presenting with acute post-operative visual loss to exclude TRAO.     

dCK expression correlates with 5-fluorouracil efficacy and HuR cytoplasmic expression in pancreatic cancer: A dual-institutional follow-up with the RTOG 9704 trial

Deoxycytidine kinase (dCK) and human antigen R (HuR) have been associated with response to gemcitabine in small studies. The present study investigates the prognostic and predictive value of dCK and HuR expression levels for sensitivity to gemcitabine and 5-fluorouracil (5-FU) in a large phase III adjuvant trial with chemoradiation backbone in pancreatic ductal adenocarcinoma (PDA). The dCK and HuR expression levels were determined by immunohistochemistry on a tissue microarray of 165 resected PDAs from the Radiation Therapy Oncology Group (RTOG) 9704 trial. Association with overall survival (OS) and disease-free survival (DFS) status were analyzed using the log-rank test and the Cox proportional hazards model. Experiments with cultured PDA cells were performed to explore mechanisms linking dCK and HuR expression to drug sensitivity. dCK expression levels were associated with improved OS for all patients analyzed from RTOG 9704 (HR: 0.66, 95% CI [0.47–0.93], P = 0.015). In a subset analysis based on treatment arm, the effect was restricted to patients receiving 5-FU (HR: 0.53, 95% CI [0.33–0.85], P = 0.0078). Studies in cultured cells confirmed that dCK expression rendered cells more sensitive to 5-FU. HuR cytoplasmic expression was neither prognostic nor predictive of treatment response. Previous studies along with drug sensitivity and biochemical studies demonstrate that radiation interferes with HuR’s regulatory effects on dCK, and could account for the negative findings herein based on the clinical study design (i.e., inclusion of radiation). Finally, we demonstrate that 5-FU can increase HuR function by enhancing HuR translocation from the nucleus to the cytoplasm, similar to the effect of gemcitabine in PDA cells. For the first time, in the pre-treatment tumor samples, dCK and HuR cytoplasmic expression were strongly correlated (chi-square P = 0.015). This dual-institutional follow up study, in a multi-institutional PDA randomized clinical trial, observed that dCK expression levels were prognostic and had predictive value for sensitivity to 5-FU.     

Effects of Long-Duration Spaceflight on Vertebral Strength and Risk of Spine Fracture

Although the negative impact of long-duration spaceflight on spine BMD has been reported, its impact on vertebral strength and risk of vertebral fracture remains unknown. This study examined 17 crewmembers with long-duration service on the International Space Station in whom computed tomography (CT) scans of the lumbar spine (L₁ and L₂) were collected preflight, immediately postflight and 1 to 4 years after return to Earth. We assessed vertebral strength via CT-based finite element analysis (CT-FEA) and spinal loading during different activities via subject-specific musculoskeletal models. Six months of spaceflight reduced vertebral strength by 6.1% (−2.3%, −8.7%) (median [interquartile range]) compared to preflight (p < 0.05), with 65% of subjects experiencing deficits of greater than 5%, and strengths were not recovered up to 4 years after the mission. This decline in vertebral strength exceeded (p < 0.05) the 2.2% (−1.3%, −6.0%) decline in lumbar spine DXA-BMD. Further, the subject-specific changes in vertebral strength were not correlated with the changes in DXA-BMD. Although spinal loading increased slightly postflight, the ratio of vertebral compressive load to vertebral strength for typical daily activities remained well below a value of 1.0, indicating a low risk of vertebral fracture despite the loss in vertebral strength. However, for more strenuous activity, the postflight load-to-strength ratios ranged from 0.3 to 0.7, indicating a moderate risk of vertebral fracture in some individuals. Our findings suggest persistent deficits in vertebral strength following long-duration spaceflight, and although risk of vertebral fracture remains low for typical activities, the risk of vertebral fracture is notable in some crewmembers for strenuous exercise requiring maximal effort. © 2019 American Society for Bone and Mineral Research.     

人脐带内皮细胞与平滑肌细胞的分离培养特照

目的：如何便捷有效地获取种子细胞是构建组织工程皮肤、角膜、血管等成功与否的关键，实验对人胎儿脐带内皮细胞和平滑肌细胞的分离、纯化、培养扩增技术进行探讨。方法：实验于2006—11在暨南大学医学院完成。①实验材料：剖宫产正常胎儿脐带由暨南大学第一临床学院提供，产妇均知情同意。②实验方法：配制培养液，A液为在M199培养液中加入20％胎牛血清、20mg，L肝素、10μg／L碱性成纤维细胞生长因子，B液为在M199培养基中加入10％胎牛血清、250mg／L G418。取脐带15-20cm，采用胶原酶“灌注消化法”获取脐带内皮细胞制成悬液，静置0．5h后利用成纤维细胞短时间内贴壁的特点，把尚未贴壁细胞吸出重新接种于含有A液的培养瓶，初步去除部分成纤维细胞，细胞贴壁24h后将培养液换为B液，继续培养3d，去除成纤维细胞，然后再用A液扩大培养。从消化完脐静脉内皮细胞的脐带中剥取脐动脉，刮除内皮细胞，将血管条剪成小块均匀贴于培养瓶底，培养瓶内加入含20％小牛血清的DMEM培养液2mL，缓慢竖直培养瓶，以培养液刚未浸没培养块为最佳，放入37℃、体积分数为0．05的CO2培养箱内干涸8h后，将培养瓶轻轻翻转，使植块刚浸入培养液中，绝对静置3d，以后每3d换液1次，待植块周围生长晕的细胞融合成片时，即可传代，传代后DMEM培养液的血清浓度由原来的20％改为5％，且在培养液中加入0．2L肝素。⑧实验评估：通过倒置相差显微镜观察细胞生长情况，分别以第Ⅷ因子、α-肌动蛋白免疫组织化学染色法鉴定内皮细胞和平滑肌细胞。结果：①内皮细胞的生长观察：接种24h后，镜下可见刚贴壁的细胞呈圆形，逐渐转变为多角形或梭形，胞间可见有成纤维细胞混杂，加入B液3d后成纤维细胞逐渐死亡。传代细胞呈“铺路石”样，细胞周围特别是近胞核处可见明显光晕，为典型的内皮细胞生长特点。②内皮细胞第Ⅷ因子相关抗原的检测：胞浆丰富且有棕黄色颗粒，细胞核不着色，呈阳性反应。⑧平滑肌细胞的生长观察：镜下组织块贴壁后5～7d可见有少数细胞从植块边缘游出，第10-15天植块周围形成明显的细胞生长晕．细胞呈长梭形、带状或三角状，有1-4个细胞核，可见半透明颗粒，第20-25天细胞密集、平行排列，形成“峰谷样”结构，是平滑肌细胞的特征性生长表现。④平滑肌细胞特异性α-肌动蛋白单克隆抗体检测：胞浆内可见棕黄色细丝，为特异性α-平滑肌肌动蛋白，细胞核不着色。结论：以胎儿脐带作为种子细胞的来源，成功分离后通过调节培养液的成分，既能排除成纤维细胞的污染又可以令内皮细胞和平滑肌细胞快速增殖。