Reactivation of heat-inactivated Ku proteins by heat shock cognate protein HSC73

Purpose: Mouse double-stranded DNA-dependent protein kinase (DNA-PK) activity is heat sensitive. Recovery of heat-inactivated DNA repair activity is a problem after combination therapy with radiation and heat. We investigated the mechanism of recovery of heat-inactivated DNA-PK activity.

Methods: Hybrid cells containing a fragment of human chromosome 8 in scid cells (RD13B2) were used. DNA-PK activity was measured by an in vitro assay. Immunoprecipitation of the nuclear extract was performed with an anti-Ku80 antibody. Proteins co-precipitated with Ku80 were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and detected by Western blotting using anti-heat shock protein (HSP)72 and anti-heat shock cognate protein (HSC)73 antibodies. HSC73 was overexpressed with the pcDNA3.1 vector. Short hairpin (sh)RNA was used to downregulate HSC73 and HSP72.

Results: The activity of heat-inactivated DNA-PK recovered to about 50% of control during an additional incubation at 37?°C after heat treatment at 44?°C for 15?min in the presence of cycloheximide (which inhibits de novo protein synthesis). Maximal recovery was observed within 3?h of incubation at 37?°C after heat treatment. Constitutively expressed HSC73, which folds newly synthesized proteins, reached maximal levels 3?h after heat treatment using a co-immunoprecipitation assay with the Ku80 protein. Inhibiting HSC73, but not HSP72, expression with shRNA decreased the recovery of DNA-PK activity after heat treatment.

Conclusions: These results suggest that de novo protein synthesis is unnecessary for recovery of some heat-inactivated DNA-PK. Rather, it might be reactivated by the molecular chaperone activity of HSC73, but not HSP72.     

利用耳甲腔型小耳畸形残耳皮瓣及软骨改善再造耳颅耳沟效果观察

目的探讨对先天性耳甲腔型小耳畸形患者行全扩张法全耳再造术后，利用残耳皮瓣改善再造耳颅耳沟的效果。方法回顾分析 2012 年 1 月—2017 年 1 月收治的 150 例先天性耳甲腔型小耳畸形患者。其中男 92 例，女 58 例；年龄 6.5～35.0 岁，平均 11.1 岁。采用一期扩张器埋置、二期全扩张法全耳再造术后发现上部颅耳沟浅显；于 6～12 个月后行三期再造耳修整。将残耳垂通过“Z”字改型转移以再造耳垂。在残耳上部作蒂在轮屏切迹的残耳上部皮瓣，弧形切开松解并加深上部颅耳沟，将上部残耳皮瓣向颅耳沟创面旋转推进缝合以覆盖创面；将带皮下组织蒂的残耳软骨组织瓣插入支架底部形成的腔隙内，并缝合固定，以增加支架的高度；耳甲腔区其余残耳皮瓣用以覆盖耳甲腔创面。结果术后拆线时 1 例患儿皮瓣远端出现直径约 0.5 cm 的表皮水疱，经换药 2 周后愈合；其余患者皮瓣成活良好。患者均获随访，随访时间 6～12 个月，平均 9.6 个月。再造耳上部颅耳沟均明显加深，再造耳支架高度不同程度增加，双耳对称性佳，耳甲腔无明显挛缩变小，再造耳外观满意。再造耳上部表面毛发明显减少，耳周发际线上移。结论采用耳甲腔型小耳畸形的残耳皮瓣及残耳软骨瓣转移，不仅可加深颅耳沟，而且可增加上部支架的高度，术后颅耳沟变形较轻，再造耳与正常耳廓的对称性更佳。     

藿香正气汤抑制新型冠状病毒复制过程的有效成分及机制初探＊

目的 收集藿香正气汤的主要活性成分，通过分子对接及网络药理学探讨其防控新型冠状病毒肺炎（COVID-19）的有效成分及治疗机制。方法 通过基于配体-蛋白质相互作用的计算方法，以瑞德西韦为对照，探索藿香正气汤潜在治疗COVID-19的成分，并选出对接较好成分进行药理学机制预测，初探其药理学机制。结果 本研究筛选出5种与新冠病毒3CLpro结合能力强于瑞德西韦的小分子成分。网络药理学初步预测抗病毒途径可能是通过PI3K-Akt 信号通路影响病毒复制。结论 成分C1-C5与3CLpro结合良好，推测其可能是潜在的3CLpro的抑制剂，为抗病毒天然药物的开发提供了理论依据。     

Policy Recommendations Regarding Skilled Nursing Facility Management of Coronavirus 19 (COVID-19): Lessons from New York State

To provide policy recommendations for managing Coronavirus 19 (COVID-19) in skilled nursing facilities, a group of certified medical directors from several facilities in New York state with experience managing the disease used e-mail, phone, and video conferencing to develop consensus recommendations. The resulting document provides recommendations on screening, protection of staff, screening of residents, management of Coronavirus 19 positive and presumed positive cases, communication during an outbreak, management of admissions and readmissions, and providing emotional support for staff. These consensus guidelines have been endorsed by the Executive Board of the New York Medical Directors Association and the Board of the Metropolitan Area Geriatrics Society.     

老年人桡骨远端C型骨折的手术治疗与非手术治疗的疗效对比

目的：探讨老年人桡骨远端C型骨折的手术治疗与非手术治疗的疗效差异，评价两种方法的优缺点。方法回顾性分析2009-12—2011-12收治的老年桡骨远端C型骨折68例，按照治疗方法分为A组(手术组)及B组(非手术组)，统计分析两组患者的临床资料。结果 A组33例， B组35例，平均随访21.5个月。两组患者的年龄、骨折类型均无差异(P＞0.05)；术后影像学指标A组优于B组，骨折愈合时间B组优于A组，治疗成本A组大于B组(P＜0.05)；Cooney评分早期A组优于B组，1年后两组无差异，两组的并发症无差异(P＞0.05)。结论老年人桡骨远端C型骨折手术治疗较非手术治疗可获得更好的复位及早期功能，但远期功能恢复无差异。     

我国日间手术开展现状与前景展望

日间手术在国外已有上百年的发展历史，现已成为欧美国家重要手术模式。我国于20世纪初开始开展日间手术，但目前尚未普及，发展不平衡问题比较突出，存在认识不清、开展不规范、与医保支付对接不畅等问题。日间手术是一种使国家、医院和病人三方均受益的新型手术模式。近年来，国家相关管理部门积极引导，开展日间手术的医院明显增多，可以预见，我国日间手术即将进入快速发展的新阶段。因此，有条件的医院可以从简单、易操作的病种开始，落实临床路径，积累经验，再逐步稳妥展开。在保证质量的前提下，不断拓展日间手术范围，提高三、四级手术比例。同时，积极与医保支付政策对接，采取灵活的方式，获得医保的支持，更好地促进我国日间手术的快速发展。     

Retinal disease in the C3 glomerulopathies and the risk of impaired vision

Background: Dense deposit disease and atypical hemolytic uremic syndrome are often caused by Complement Factor H (CFH) mutations. This study describes the retinal abnormalities in dense deposit disease and, for the first time, atypical haemolytic uremic syndrome. It also reviews our understanding of drusen pathogenesis and their relevance for glomerular disease. Methods: Six individuals with dense deposit disease and one with atypical haemolytic uremic syndrome were studied from 2 to 40 years after presentation. Five had renal transplants. All four who had genetic testing had CFH mutations. Individuals underwent ophthalmological review and retinal photography, and in some cases, optical coherence tomography, and further tests of retinal function. Results: All subjects with dense deposit disease had impaired night vision and retinal drusen or whitish-yellow deposits. Retinal atrophy, pigmentation, and hemorrhage were common. In late disease, peripheral vision was restricted, central vision was distorted, and there were scotoma from sub-retinal choroidal neovascular membranes and atypical serous retinopathy. Drusen were present but less prominent in the young person with atypical uremic syndrome due to a heterozygous CFH mutation. Conclusions: Drusen are common in forms of C3 glomerulopathy caused by compound heterozygous or heterozygous CFH mutations. They are useful diagnostically but also impair vision. Drusen have an identical composition to glomerular deposits. They are also identical to the drusen of age-related macular degeneration, and may respond to the same treatments. Individuals with a C3 glomerulopathy should be assessed ophthalmologically at diagnosis, and monitored regularly for vision-threatening complications.     

Magnesium modification of a calcium phosphate cement alters bone marrow stromal cell behavior via an integrin-mediated mechanism

The chemical composition, structure and surface characteristics of biomaterials/scaffold can affect the adsorption of proteins, and this in turn influences the subsequent cellular response and tissue regeneration. With magnesium/calcium phosphate cements (MCPC) as model, the effects of magnesium (Mg) on the initial adhesion and osteogenic differentiation of bone marrow stromal cells (BMSCs) as well as the underlying mechanism were investigated. A series of MCPCs with different magnesium phosphate cement (MPC) content (0∼20%) in calcium phosphate cement (CPC) were synthesized. MCPCs with moderate proportion of MPC (5% and 10%, referred to as 5MCPC and 10MCPC) were found to effectively modulate the orientation of the adsorbed fibronectin (Fn) to exhibit enhanced receptor binding affinity, and to up-regulate integrin α5β1 expression of BMSCs, especially for 5MCPC. As a result, the attachment, morphology, focal adhesion formation, actin filaments assembly and osteogenic differentiation of BMSCs on 5MCPC were strongly enhanced. Further in vivo experiments confirmed that 5MCPC induced promoted osteogenesis in comparison to ot her CPC/MCPCs. Our results also suggested that the Mg on the underlying substrates but not the dissolved Mg ions was the main contributor to the above positive effects. Based on these results, it can be inferred that the specific interaction of Fn and integrin α5β1 had predominant effect on the MCPC-induced enhanced cellular response of BMSCs. These results provide a new strategy to regulate BMSCs adhesion and osteogenic differentiation by adjusting the Mg/Ca content and distribution in CPC, guiding the development of osteoinductive scaffolds for bone tissue regeneration.