超声扫查晚孕期胎儿动脉导管形态改变的临床意义

目的探讨超声扫查晚孕期胎儿单纯性动脉导管形态改变的临床意义。方法 23例晚孕期孕妇超声诊断为单纯性动脉导管迂曲的胎儿,使用心脏多切面扫查方式观察动脉导管的形态,测量动脉导管的内径,出生后随访2~3个月。结果 23例单纯性动脉导管迂曲的胎儿,其中11例动脉导管轻度弯曲呈"C"形,内径均匀;5例明显弯曲呈"S"形,内径均匀;另7例明显弯曲呈"S"形,内径不均,局部扩张形成动脉瘤。所有胎儿产后动脉导管均正常闭合,心脏结构和功能未见异常。结论胎儿动脉导管迂曲显著者可局部扩张形成动脉导管瘤;单纯性动脉导管迂曲但无心脏其他异常时可能不影响胎儿的预后。     

50例中西医结合治疗单纯疱疹病毒性角膜炎的疗效观察和护理

目的:观察中西医结合用药对单纯疱疹病毒性角膜炎的治疗效果.方法:50例单纯疱疹病毒性角膜炎患者分成观察组25例(29只眼)和对照组25例(28只眼);对照组按照常规局部用利巴韦林眼液、加替沙星眼液、更昔洛韦眼膏,口服维生素B2,维生素C,维生素AD丸,阿昔洛韦片及静脉滴注病毒唑针.观察组常规加中药方剂治疗.进行疗效对比观察.结果:观察组治愈27眼,显效2眼,治愈时间(7±2.3)d.1年复发率为3.5%;对照组治愈20眼,显效4眼,无效4眼,治愈时间(20±3.6)d,1年复发率为34.5%.2组治疗效果、治愈时间、复发率差异有显著性(P＜0.01,P＜0.05,P＜0.01).结论:中西医结合治疗单纯疱疹病毒性角膜炎,结合动态护理.可显著提高疗效,大大缩短疗程,大大减少复发,节省了医疗费用.     

Structure and dynamics of SARS-CoV-2 proofreading exoribonuclease ExoN

High-fidelity replication of the large RNA genome of coronaviruses (CoVs) is mediated by a 3′-to-5′ exoribonuclease (ExoN) in nonstructural protein 14 (nsp14), which excises nucleotides including antiviral drugs misincorporated by the low-fidelity viral RNA-dependent RNA polymerase (RdRp) and has also been implicated in viral RNA recombination and resistance to innate immunity. Here, we determined a 1.6-Å resolution crystal structure of severe acute respiratory syndrome CoV 2 (SARS-CoV-2) ExoN in complex with its essential cofactor, nsp10. The structure shows a highly basic and concave surface flanking the active site, comprising several Lys residues of nsp14 and the N-terminal amino group of nsp10. Modeling suggests that this basic patch binds to the template strand of double-stranded RNA substrates to position the 3′ end of the nascent strand in the ExoN active site, which is corroborated by mutational and computational analyses. We also show that the ExoN activity can rescue a stalled RNA primer poisoned with sofosbuvir and allow RdRp to continue its extension in the presence of the chain-terminating drug, biochemically recapitulating proofreading in SARS-CoV-2 replication. Molecular dynamics simulations further show remarkable flexibility of multidomain nsp14 and suggest that nsp10 stabilizes ExoN for substrate RNA binding to support its exonuclease activity. Our high-resolution structure of the SARS-CoV-2 ExoN–nsp10 complex serves as a platform for future development of anticoronaviral drugs or strategies to attenuate the viral virulence.

The 29.9-kb single-stranded RNA genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the global COVID-19 pandemic, is replicated and transcribed by the viral RNA-dependent RNA polymerase (RdRp, nsp12) (1–3). Unlike the high-fidelity cellular replicative DNA polymerases, viral RdRp enzymes, including the CoV RdRp, do not contain a proofreading exonuclease domain to ensure high fidelity. The resulting higher mutation rate (10⁻⁴ to 10⁻⁶ substitutions per nucleotide per round of replication) is generally thought to promote rapid viral adaptation in response to selective pressure (4–6). However, the lack of proofreading activity in RdRp poses a particular challenge for the replication of CoVs, which feature the largest known RNA virus genomes (27 to 32 kb, up to twice the length as the next-largest nonsegmented RNA viral genomes) (7, 8). It has been reported that SARS-CoV nsp12 is the fastest viral RdRp known but with an error rate more than one order of magnitude higher than the generally admitted error rate of viral RdRps (9), clearly necessitating a unique proofreading mechanism.To mitigate the low fidelity of RdRp, all coronaviruses encode a 3′-to-5′ exoribonuclease (ExoN) in multifunctional nsp14 (10–12), which forms a complex with nsp10 critical for the ExoN activity, and additionally contains a C-terminal guanine N7 methyl transferase (N7-MTase) domain. Mutations of SARS-CoV-2 nsp14 exhibit strong association with increased genome-wide mutation load (13, 14), and genetic inactivation of ExoN in engineered SARS-CoV and murine hepatitis virus (MHV) leads to 15- to 20-fold increases in mutation rates (7, 15, 16). Furthermore, in a mouse model, SARS-CoV with inactivated ExoN shows a mutator phenotype with decreased fitness and lower virulence over serial passage, suggesting a potential strategy for generating a live, impaired-fidelity coronavirus vaccine (17). Alternatively, recent studies show that ExoN inactivation abrogates replication of SARS-CoV-2 and Middle East Respiratory Syndrome CoV (18), hinting at additional functions for ExoN in viral replication. Indeed, ExoN activity has been reported to mediate the extensive viral RNA recombination required for subgenomic messenger RNA (mRNA) synthesis during normal replication of CoVs, including SARS-CoV-2 (19), and it was shown to be required for resistance to the antiviral innate immune response for MHV (20). ExoN inactivation also significantly increases the sensitivity of CoVs to nucleoside analogs that target RdRp, which is consistent with the biochemical activity of ExoN to excise mutagenic or chain-terminating nucleotides misincorporated by RdRp (21–23). These observations combine to suggest that chemical inhibition of ExoN could be an effective antiviral strategy against CoVs. In this study, we determined high-resolution crystal structures of the SARS-CoV-2 ExoN–nsp10 complex and studied its biochemical activities. Furthermore, we used molecular dynamics (MD) simulations to better understand the dynamics of nsp14, nsp10, and their interaction with RNA.     

雌激素调节大鼠去卵巢后骨髓细胞OPG、RANKL、RANK基因表达

目的 观察大鼠去卵巢后骨髓细胞核因子κB受体活化子配体（RANKL）、核因子κB受体活化子（RANK）、护骨素（OPG）以及TNF-α基因表达的改变和雌激素的影响。方法 健康3m龄雌性SD大鼠72只，24只为假手术对照组，48只去卵巢，随机分为去卵巢组和雌激素组，每组24只。分别于去卵巢后2、4、6、12w每组各取6只大鼠骨髓细胞提取RNA，RT-PCR半定量分析其表达。结果 与对照组相比，去卵巢后2W．去卵巢组骨髓细胞TNF-α和RANKLmRNA表达显著升高（P〈0．05—0．01），第4-6w，上述改变达高峰，至第12w TNF-α仍呈有意义增高；而OPG表达在第2-6W则明显降低（P〈0．01），2-4W为最低点；OPG／RANKL比值2-6W为最低（P〈0．01），12W仍低于对照组。雌激素组以上各时间TNF-α和RANKL表达低于去卵巢组（P〈0．05，P〈0．01）而OPG表达和OPG／RANKL比值明显高于去卵巢组（P〈0．01）。各组全程未见RANK基因表达水平有明显变化。结论 雌激素抑制大鼠去卵巢后骨髓细胞过度表达RANKL和TNF-α而增加OPG的表达。     

台州市2017-2018年新报告HIV/AIDS巨细胞病毒血症现患率及影响因素研究

目的:了解2017-2018年台州市新报告且未接受抗病毒治疗（ART）的HIV/AIDS血浆巨细胞病毒血症现患率及其影响因素。方法:收集台州市新报告且未接受ART的成年HIV/AIDS血浆样本,提取核酸后采用荧光定量PCR检测巨细胞病毒DNA水平,采用单因素与多因素logistic回归分析其影响因素。结果:研究对象61...     

USP35 mitigates endoplasmic reticulum stress‐induced apoptosis by stabilizing RRBP1 in non‐small cell lung cancer

Deubiquitinating enzymes (DUBs) serve to maintain cellular homeostasis via protein ubiquitination and exert diverse regulatory functions in cancers and other diseases. Much progress has been made in characterizing biological roles of DUBs over the decades, yet the specific functions of many subclass members remain largely unexplored. It was not until recent years that the role of ubiquitin‐specific‐processing protease 35 (USP35) in cancers began to be understood. Here, we focus on delineating the roles and underlying mechanisms of USP35 in non‐small cell lung cancer (NSCLC). The isobaric tags for relative and absolute quantitation (iTRAQ) comparative proteomic approach were employed to identify differentially expressed proteins (DEPs) in H1299 cells induced by USP35 overexpression or silencing. Among the potential interactome of USP35, ribosome‐binding protein 1 (RRBP1), a membrane‐bound protein in endoplasmic reticulum (ER), captured our attentions. RRBP1 expression was found to positively correlate with USP35 levels in both genetically modified cells and human NSCLC tissues. Concordantly, both RRBP1 expression and USP35 expression were found to positively correlate with poor prognoses in lung adenocarcinoma patients. At the molecular level, USP35 was verified to directly interact with RRBP1 to prevent it from proteasomal‐dependent degradation. Functionally, USP35 alleviated ER stress‐induced cell apoptosis by stabilizing RRBP1 in NSCLC cells. Collectively, these findings indicate that USP35 plays a critical role in resisting ER stress‐induced cell death through deubiquitinating RRBP1, hence providing a rationale to target the USP35‐RRBP1 axis as an alternative therapeutic option for NSCLC.     

藤黄酸抗肿瘤作用机制及联合用药研究进展

恶性肿瘤是全球面临的共同难题,同时也给世界各国带来了超负荷的经济负担。藤黄酸是藤黄Garcinia hanburyi中一种笼状呫吨酮类活性成分,具有抗炎、改善视网膜病变、脏器保护等多种药理活性。近年来,大量研究证实藤黄酸可作为一种潜力巨大的抗肿瘤化合物用于肝癌、肺癌、乳腺癌、结直肠癌等多种癌症的治疗,其机制涉及抑制细胞增殖、阻碍迁移和侵袭、诱导凋亡和自噬、抑制血管生成、诱导铁死亡和焦亡、靶向肿瘤炎症微环境和免疫调控等。此外,大量研究发现藤黄酸可与多种化疗药物或天然产物联合用于癌症的协同治疗。因此,重点总结了藤黄酸的抗肿瘤作用机制及其协同其他药物抗肿瘤的研究进展,为藤黄酸抗肿瘤研究提供参考依据。     

二尖瓣副瓣及主动脉瓣下隔膜共同导致左室流出道梗阻外科治疗一例

左室流出道梗阻在先天性心脏病中发病率相对较低,本文报道一例二尖瓣副瓣及主动脉瓣下隔膜共同导致左室流出道梗阻的罕见病例。13岁男性被发现二尖瓣副瓣起自主动脉二尖瓣幕帘,呈囊袋状,并有独立腱索连接至前外侧乳头,左室收缩期与主动脉瓣下隔膜共同导致左室流出道重度狭窄。通过手术切除二尖瓣副瓣及主动脉瓣下隔膜,梗阻成功解除,术后复查手术效果良好。     

CHA2DS2-VASc评分对急性心肌梗死患者院内结局事件的预测价值——China PEACE回顾性急性心肌梗死研究

目的评估CHA₂DS₂-VASc评分对急性心肌梗死(AMI)患者院内结局事件的预测价值。方法回顾性分析冠心病医疗结果评价和临床转化研究(China PEACE)回顾性急性心肌梗死研究中23728例AMI患者的病历信息,按CHA₂DS₂-VASc评分分为低(0~3分)、中(4~6分)、高(7~9分)分值组。院内结局包括主要不良心血管事件、死亡、死亡或放弃治疗、再发心肌梗死、缺血性卒中等。采用多因素Cox回归分析CHA₂DS₂-VASc评分对AMI患者院内结局的影响。通过受试者工作特征(ROC)曲线,评估CHA₂DS₂-VASc评分对AMI患者院内死亡与死亡或放弃治疗的预测价值。结果入组患者年龄66(56,75岁)岁,女性占30.7%。CHA₂DS₂-VASc评分高分值组患者院内结局事件发生率更高,基础疾病更多(P值均<0.001);多因素logistic回归中,院内病死率(OR=6.13,95%CI 4.77~7.87,P<0.001)、院内死亡或放弃治疗率(OR=6.43,95%CI 5.16~8.00,P<0.001)、主要心血管事件发生率(OR=4.94,95%CI 4.06~6.01,P<0.001)明显高于其他两组。ROC曲线分析显示,无论院内病死率,还是死亡或放弃治疗率,CHA₂DS₂-VASc评分与简化版全球急性冠状动脉事件登记(global registry of acute coronary events,mini-GRACE)评分相比差异无统计学意义(ROC曲线下面积:0.699与0.696,P=0.752;0.708与0.713,P=0.489)。结论CHA₂DS₂-VASc评分是一种有效预测AMI患者院内风险的评估工具,该评分操作简单,预测价值与mini-GRACE评分相当。     

多发性骨髓瘤患者行自体造血干细胞移植效果的相关因素研究

〔目的〕探究多发性骨髓瘤患者行自体造血干细胞移植效果的相关因素.〔方法〕回顾性分析2019年2月至2020年2月在某医院进行多发性骨髓瘤治疗的63例患者的临床资料.根据国际骨髓瘤工作组疗效标准,用总生存时间和无进展生存时间评价多发性骨髓瘤患者的治疗效果,采用Kaplan-Meier单因素分析法及Cox多因素回归模型分析...