Dromedary camel nanobodies broadly neutralize SARS-CoV-2 variants

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike is a trimer of S1/S2 heterodimers with three receptor-binding domains (RBDs) at the S1 subunit for human angiotensin-converting enzyme 2 (hACE2). Due to their small size, nanobodies can recognize protein cavities that are not accessible to conventional antibodies. To isolate high-affinity nanobodies, large libraries with great diversity are highly desirable. Dromedary camels (Camelus dromedarius) are natural reservoirs of coronaviruses like Middle East respiratory syndrome CoV (MERS-CoV) that are transmitted to humans. Here, we built large dromedary camel V_HH phage libraries to isolate nanobodies that broadly neutralize SARS-CoV-2 variants. We isolated two V_HH nanobodies, NCI-CoV-7A3 (7A3) and NCI-CoV-8A2 (8A2), which have a high affinity for the RBD via targeting nonoverlapping epitopes and show broad neutralization activity against SARS-CoV-2 and its emerging variants of concern. Cryoelectron microscopy (cryo-EM) complex structures revealed that 8A2 binds the RBD in its up mode with a long CDR3 loop directly involved in the ACE2 binding residues and that 7A3 targets a deeply buried region that uniquely extends from the S1 subunit to the apex of the S2 subunit regardless of the conformational state of the RBD. At a dose of ≥5 mg/kg, 7A3 efficiently protected transgenic mice expressing hACE2 from the lethal challenge of variants B.1.351 or B.1.617.2, suggesting its therapeutic use against COVID-19 variants. The dromedary camel V_HH phage libraries could be helpful as a unique platform ready for quickly isolating potent nanobodies against future emerging viruses.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent of COVID-19 (1, 2) that enters human cells by binding its envelope anchored type I fusion protein (spike) to angiotensin-converting enzyme 2 (ACE2) (3, 4). The SARS-CoV-2 spike is a trimer of S1/S2 heterodimers with three ACE2 receptor-binding domains (RBDs) attached to the distal end of the spike via a hinge region that allows conformational flexibility (4). In the all-down conformation, the RBDs are packed with their long axes contained in a plane perpendicular to the axis of symmetry of the trimer. Transition to the roughly perpendicular up conformation exposes the receptor-binding motif (RBM), located at the distal end of the RBD, which is sterically occluded in the down state. Numerous neutralizing antibodies targeting the spike, particularly its RBD, have been developed to treat COVID-19 using common strategies such as single B cell cloning, animal immunization, and phage display (5–9). Most vaccines, including those that are messenger RNA based, are designed to induce immunity against the spike or RBD (10–12). However, emerging SARS-CoV-2 variants such as D614G, B.1.1.7 (Alpha, United Kingdom), B.1.351 (Beta, South Africa), and P.1 (Gamma, Brazil) have exhibited increased resistance to neutralization by monoclonal antibodies or postvaccination sera elicited by the COVID-19 vaccines (13, 14). Monoclonal antibodies with Emergency Use Authorization for COVID-19 treatment partially (Casirivimab) or completely (Bamlanivimab) failed to inhibit the B.1.351 and P.1 variants. Similarly, these variants were less effectively inhibited by convalescent plasma and sera from individuals vaccinated with a COVID-19 vaccine (BNT162b2) (13). The B.1.617.2 (Delta, India) variant became the prevailing strain in many countries (15). Highly effective and broadly neutralizing antibody therapy is urgently demanded for COVID-19 patients.Due to their small size and unique conformations, camelid V_HH single-domain antibodies (also known as nanobodies) can recognize protein cavities that are not accessible to conventional antibodies (16). To isolate high-affinity nanobodies without a need for further affinity maturation, it is highly desirable to construct large nanobody libraries with great diversity. Dromedary camels have been found as potential natural reservoirs of Middle East respiratory syndrome CoV (MERS-CoV) (17). We speculated that dromedary camels would be an ideal source of neutralizing nanobodies against coronaviruses. In the present study, we built large camel V_HH single-domain antibody phage libraries with a diversity of over 10¹¹ from six dromedary camels (Camelus dromedarius), three males and three females, with ages ranging from 3 mo to 20 y. We used both the SARS-CoV-2 RBD and the stabilized spike ectodomain trimer protein as baits to conduct phage panning for nanobody screening. Among all the binders, we found NCI-CoV-7A3 (7A3), NCI-CoV-1B5 (1B5), NCI-CoV-8A2 (8A2), and NCI-CoV-2F7 (2F7) to be potent ACE2 blockers. In addition, these dromedary camel nanobodies displayed potent neutralization activity against the B.1.351 and B.1.1.7 variants and the original strain (Wuhan-Hu-1). The cryoelectron microscopy (cryo-EM) structure of the spike trimer protein complex with these V_HH nanobodies revealed two distinct nonoverlapping epitopes for neutralizing SARS-CoV-2. In particular, 7A3 recognizes a unique and deeply buried region that extends to the apex of the S2 subunit of the spike. Combined treatment with 7A3 and 8A2 shows more potent protection against various variants in culture and mice infected with the B.1.351 variant. Interestingly, 7A3 alone retains its neutralization activity against the lethal challenge of the B.1.617.2 variant in mice.     

静脉输注利多卡因在无痛结肠镜检查中的临床应用

目的 观察静脉输注利多卡因在无痛结肠镜检查中的临床效果,探讨其有效性和安全性.方法 选择在该院接受无痛结肠镜检查的患者90例,采用随机数字表法分为3组:舒芬太尼复合丙泊酚组(S组)、利多卡因复合丙泊酚组(L组)和单纯丙泊酚组(P组),每组30例.采用双盲法分别给予每组患者相应药物,持续监测并记录给药前(T0)、睫毛反射...     

基于循证医学的产妇手术切口护理对剖宫产切口美观性及情绪状态的影响

目的 探讨基于循证医学的切口护理模式对剖宫产切口美观性及情绪状态的影响。方法 选取 2022年6月-2023年6月南京医科大学附属妇产医院/南京市妇幼保健院行剖宫产的102例初产妇作为研究对 象,随机分为对照组和观察组,每组51例。对照组实施常规护理,观察组则在此基础上予以基于循证医 学的切口护理模式,比较两组患者瘢痕评价量表（PSAS）、观察者瘢痕评价量表（OSAS）、皮肤科生 活质量指数（DLQI）、Zung抑郁自评量表（Zung-SDS）等级以及Zung焦虑自评量表（Zung-SAS）。 结果 观察组PSAS、OSAS、DLQI各维度评分及总分低于对照组（P ＜0.05）;观察组Zung-SDS抑郁等 级、（Zung-SAS）焦虑等级优于对照组（P＜0.05）。结论 基于循证医学的产妇手术切口护理有助于改善 术后切口美观度,提高生活质量,减轻其心理压力,降低抑郁和焦虑的发生率。     

Experimental and Numerical Study on Uniaxial Compression Failure of Concrete Confined by Nylon Ties

The developments in the cisvil engineering fields have led to an increased demand for structural reinforcements. Therefore, designing an effective, green, convenient, and low-cost reinforcement method is considerably important. Nylon ties have high strength and good heat resistance, and they can retain good tensile properties after high-temperature cooling. Further, they are inexpensive and can be recycled. Thus, they are considered suitable for structural reinforcement engineering. In this study, the core concrete was reinforced by the active confinement of prestressed nylon ties. A uniaxial compression test was performed to evaluate the reinforcement effect of the preload generated by the high-temperature cooling of the tie rod on the core concrete. The results show that nylon ties can effectively improve the mechanical properties of the core concrete. Combined with numerical simulation technology, a damage model of a confined concrete column (CC) was established, and the damage evolution law of CC under uniaxial axial compression was analyzed. Combined with numerical simulation and experimental research, the effectiveness of nylon tie reinforced concrete and the reliability of the damage model were verified, providing a reference for research on engineering reinforcement.     

良性脑膜瘤中PR、VEGF表达及PCNA、Ki-67标记指数与肿瘤复发间的关系

目的 通过对孕激素受体（PR）、血管内皮细胞生长因子（VEGF）表达及肿瘤增殖指标增殖细胞核抗原（PCNA）、Ki-67表达量的分析,探讨上述诸因素与肿瘤复发间的关系。方法 56例脑膜瘤标本分为复发组（n=30）、初发组（n=26）,应用免疫组织化学方法检测其PR、VEGF表达情况,同时检测PCNA、Ki-67的表达量,统计学分析它们与肿瘤复发间的关系。结果 复发组PCNA LI（75±7）%,明显高于初发组（26±7）%;复发组Ki-67 LI（4.0±4.6）%,高于初发组（1.1±1.7）%;PR表达阳性：复发组7例（23.33%）,初发组21例（80.77%）;VEGF表达阳性：复发组13例（43.33%）,初发组9例（34.62%）。结论 PCNA LI、Ki-67及PR表达与脑膜瘤复发有一定的关系,而VEGF表达无统计学意义。     

医患关系的沟通

沟通来源于法语en rappart,词义为和睦相处,医生和病人第一次见面时很容易建立沟通关系,建立沟通后,病人接受医生治疗方案的可能性增大,即便医疗过程或结果不是很完美,病人也容易谅解.     

胆汁胰液混合液溶解颈动脉粥样硬化斑块的体外实验研究

目的观察并评价胆汁胰液混合液在体外对颈动脉粥样硬化斑块的溶解效果。方法把手术取出的颈动脉粥样硬化斑块分为不稳定斑块与稳定斑块,在37℃下分别加入新鲜胆汁胰液混合液,观察并记录二者在胆汁胰液混合液中的溶解情况。结果不稳定斑块和稳定斑块内层的脂质核心均可迅速被胆汁胰液混合液软化溶解,而外层的纤维帽则均不被溶解。不稳定斑块因脂质核心占比大而溶解效果显著,而稳定斑块因其脂质核心小,溶解效果相对较差。结论本研究发现胆汁胰液混合液中的某种或某几种成分对颈动脉粥样硬化斑块有一定的溶解作用,本研究尝试提出可能的溶解机制,并在下一步探究胆汁胰液混合液中溶解颈动脉粥样硬化斑块的有效成分。     

二氢埃托啡依赖80例临床分析

目的：分析二氢埃托啡依赖者的临床表现。方法：对80例二氢埃托啡依赖者的临床资料进行分析,并分析这80例依赖者所填写的药物依赖性调查表的结果。在患者入院后的第一周开始给予支持疗法进行治疗。结果：80例二氢埃托啡依赖者中男女比例为4：1,初中文化程度的人最多,32人、个体户、无业人员占82％;大多数患者不知道二氢埃托啡可以成瘾。滥用二氢埃托啡的平均时间是（3．1±2．4）月,用量为（6．4±4．6）片。停用药物后,患者全部出现戒断症状。二氢埃托啡的戒断症状比较轻,出现早,消失快,容易戒断。联合疗法治疗二氢埃托啡依赖的效果明显。结论：联合疗法治疗二氢埃托啡依赖效果明显,值得推广。     

Effects of Combination of Calcium and Aspirin on Azoxymethane-Induced Aberrant Crypt Foci Formation in the Colons of Mice and Rats

Human intervention studies have suggested an exciting synergistic action between calcium supplementation and aspirin intake in reducing the risk of colorectal cancer. The aim of this study was to determine whether such a synergy can be demonstrated on azoxymethane (AOM)-induced colon aberrant crypt foci (ACF) formation in mice and rats. Female CF-1 mice and male F344 rats were injected subcutaneously with AOM and then received diet treatments for 8 wk. The basal control diet contained high fat (20% mixed lipids by weight) and low calcium (1.4 mg/g diet) to mimic the average Western diet. The treatment diets contained enriched calcium (5.2 mg calcium/g diet), aspirin (0.2 mg aspirin/g diet), or calcium plus aspirin (5.2 mg calcium plus 0.2 mg aspirin/g diet). Treatment with calcium, aspirin, or their combination significantly decreased the number of total ACF and aberrant crypt per mouse (by 43–59%) or rat (by 23–38%), but statistically significant differences among the 3 groups were not observed. A hint of additivity between calcium and aspirin was observed in mice but not in rats. These results indicate that the combination of calcium and aspirin did not produce a synergistic effect on the ACF formation in AOM-treated mice and rats.