Hysteroscopic removal of foreign bodies and its method of monitoring

Objective To evaluate transcervical removal of foreign bodies(TCRF)and to estimate the effectiveness of its monitoring methods.Methods One hundred and thirteen women were identified as having residual intrauterine devices(IUD),residual pregnancy products,unabsorbed strings and broken hooks,which were not removed during routine curettage of IUD removal.All patients were monitored using B ultrasonography while TCRF was performed.Four cases were monitored by laparoscopy simultaneously.One case was monitored by laparoscopic ultrasonography.Results Foreign bodies of one hundred and nine patients were taken out by TCRF.Uterine bleeding, amenorrhoea,discharge,abdominal pain,mlcturition and hematuria disappeared postoperatively.Fetal bones embedded into intramural uterin in four cases were not removed completely.Of these four,one became pregnant 4 months later after TCR and term delivered.One case encountered uterine perforation that was sutured by laparoscopy.Conclusions TCRF is safe and efficient.Sufficient cervical canal distension,selection of equipment and methods to be used is important for successful TCRF.As a non-invasive and effective monitoring method,B ultrasonography is the first choice to monitor for TCRF.For patients with high risk factors for uterine perforation,laparoscopic monitoring should be done simultaneously.Laparoscopic ultrasonography monitoring has both the advantages of B ultrasonography and laparoscopy monitoring,but is invasive and expensive.     

2型糖尿病患者LP(a)水平与代谢综合征的关系

目的研究2型糖尿病患者LP(a)水平与伴发的代谢综合征组分相关性。方法采用横断面研究对上海地区1040例2型糖尿病患者进行了LP(a)水平的调查，同时采用Spearman单因素相关、Partial偏相关分析LP(a)与代谢综合征各组分的相关性，同时根据患者伴发代谢综合征组分数目分组，并对组间LP(a)水平进行统计分析。结果2型糖尿病患者LP(a)水平与尿微量白蛋白排泄率、血尿酸、空腹血糖及低密度脂蛋白胆固醇呈显著正相关性，而与胰岛素敏感指数呈显著负相关，但与肥胖、血压等无明显关联。同时LP(a)水平随着伴发代谢综合征组分数目的增加而明显升高。结论LP(a)水平与代谢综合征关系密切；监测2型糖尿病患者LP(a)水平有助于了解2型糖尿病患者伴发代谢综合征的情况；降低LP(a)水平有利于预防2型糖尿病患者慢性并发症的发生。     

军人失眠症患者睡眠的认知心理特点与个性特征的相关研究

目的探讨军人失眠症患者对睡眠的认知心理特点及与个性特征的关系。方法采用睡眠的个人信念和态度量表(DBAS)和艾森克个性问卷-成人版(EPQ)对48例军人失眠症患者(失眠症组)进行调查分析,并随机抽取某部50例官兵作为对照组。结果失眠症组患者的DBAS总分及各因子分和对照组比较,差异均有统计学意义(P<0.05,P<0.01);EPQ的内外向和神经质因子分与对照组比较差异有统计学意义(P<0.01);DBAS总分及各因子分和神经质呈正相关(r=0.159～0.234;P<0.05,P<0.01),与内外向呈负相关(r=-0.162～-0.238;P<0.05,P<0.01)。结论军人失眠症患者存在着大量与睡眠相关的错误认知,个性特征与这些错误认知有明显的相关性。     

2004年宁波大学流感爆发病毒株的血凝素基因分析

目的了解宁波地区流行性感冒(流感)病毒株的变异情况。方法采集2004年5月宁波大学流感爆发期间病人的含漱液进行病毒分离、鉴定，并对其中1株病毒的血凝素重链区进行了核苷酸和氨基酸序列分析。结果在9份样品中共分离到流感病毒3株，经血清学试验鉴定为甲3型。与2002年宁波市流感病毒流行株的核苷酸同源性为98．2％-98．3％，氨基酸同源性为96．7％-97．3％；与2003年流行株的核苷酸同源性为98．7％，氨基酸同源性为97．6％；与参考株A／Sydney／05／1997的核苷酸同源性为95．9％，氨基酸同源性为92．7％；与参考株A／Wuhan／359／1995的核苷酸同源性为94．6％，氨基酸同源性为91．2％。结论2004年宁波大学流感爆发的病毒为甲3型。其HA1区序列更接近2003年流行毒株，与A／Sydney／05／1997毒株的同源性要高于A／Wuhan／359／1995。该爆发流行的毒株可能是在宁波以前流行毒株的基础上进化而来的。     

RGD和TAT共修饰紫杉醇脂质体的构建及其体外抗肿瘤研究

目的：制备三肽序列精氨酸-甘氨酸-天冬氨酸(Arg-Gly-Asp,RGD)和细胞穿膜肽TAT共修饰紫杉醇(PTX)脂 质体(RGD/TAT-LP-PTX),对其理化性质进行表征,并研究脂质体与乳腺癌MCF-7细胞的亲和力和增殖抑制作用。方 法：采用薄膜分散法制备RGD/TAT-LP-PTX,考察脂质体的粒径、电位以及包封率;通过定量细胞摄取实验研究乳 腺癌MCF-7细胞对RGD/TAT-LP的摄取效率以及脂质体的摄取机制。定性共聚焦实验观察肿瘤细胞对脂质体的摄取。 MTT实验研究RGD/TAT-LP-PTX对乳腺癌MCF-7细胞的细胞毒性;构建乳腺癌MCF-7细胞肿瘤球模型,研究脂质体对 肿瘤球的穿透能力。结果：RGD/TAT-LP-PTX的粒径为(138.8±12.4) nm,电位为(25.85±2.75) mV,紫杉醇的包封率为 88.3%。细胞摄取实验结果显示：RGD/TAT-LP在孵育4 h时的摄取效率是2 h的1.79倍(P<0.05);乳腺癌MCF-7细胞在 与脂质体共同孵育4 h后对RGD/TAT-LP的摄取效率分别是TAT-LP,RGD-LP和LP的2.25倍、2.72倍和4.58倍(P<0.01); RGD/TAT-LP-PTX对乳腺癌MCF-7细胞的增殖抑制率随时间的延长而增长,RGD/TAT-LP-PTX在孵育48 h时对乳腺癌 MCF-7细胞的抑制率是24 h的1.78倍(P<0.05);在给予RGD/TAT-LP-PTX,TAT-LP-PTX,RGD-LP-PTX和LP-PTX四种 脂质体药物48 h后,RGD/TAT-LP-PTX组的抑制率是TAT-LP-PTX,RGD-LP-PTX和LP-PTX的1.65倍、1.82倍和2.55倍 (P<0.01)。RGD/TAT-LP对肿瘤球的穿透能力明显强于其他脂质体。结论：RGD和细胞穿膜肽TAT共修饰PTX脂质体能 够有效识别并穿透肿瘤细胞膜进入肿瘤细胞,是一种潜在高效的乳腺癌给药系统。     

紫外分光光度法测定芒果苷苷元的解离常数

目的：采用紫外分光光度法测定芒果苷苷元的解离常数。方法将芒果苷苷元溶于一系列的pH值磷酸缓冲盐溶液中,并在芒果苷苷元合适的波长处分别测定吸光值并计算其pKa值。结果以253nm和315nm作为分析波长,利用作图软件拟合曲线求出拐点即是芒果苷苷元的解离常数,计算得到平均值为6.72。结论通过紫外分光光度法测定了芒果苷元的解离常数,对进一步研究芒果苷苷元的吸收、分布、代谢和排泄等具有重要的参考意义。该方法简单快速,准确可靠。     

大龄近视患者LASIK的特点及临床分析

目的:探讨对大龄近视患者施行准分子激光原位角膜磨镶术(LASIK)的手术设计特点及疗效。方法:对48例、96眼≥40岁的近视患者行LASIK治疗,并对术前屈光度、预矫度数、手术疗效等与对照组(<40岁,54例、108眼)进行比较分析。结果:大龄近视患者术后6月时远视力平均为0.97±0.30,虽然低于同期低龄对照组足矫视力(1.18±0.19),但优于拟矫度数眼镜时对应的平均视力(0.74±0.16)。近视力达到J1的比例低于对照低龄组,干眼的症状比低龄组明显。结论:大龄近视患者进行LASIK手术安全、有效。鉴于年龄所造成的老视,需减少实际度数矫正,以兼顾术后远、近视力。     

Cryo-EM structure of DNA-bound Smc5/6 reveals DNA clamping enabled by multi-subunit conformational changes

Structural maintenance of chromosomes (SMC) complexes are essential for chromatin organization and functions throughout the cell cycle. The cohesin and condensin SMCs fold and tether DNA, while Smc5/6 directly promotes DNA replication and repair. The functions of SMCs rely on their abilities to engage DNA, but how Smc5/6 binds and translocates on DNA remains largely unknown. Here, we present a 3.8 Å cryogenic electron microscopy (cryo-EM) structure of DNA-bound Saccharomyces cerevisiae Smc5/6 complex containing five of its core subunits, including Smc5, Smc6, and the Nse1-3-4 subcomplex. Intricate interactions among these subunits support the formation of a clamp that encircles the DNA double helix. The positively charged inner surface of the clamp contacts DNA in a nonsequence-specific manner involving numerous DNA binding residues from four subunits. The DNA duplex is held up by Smc5 and 6 head regions and positioned between their coiled-coil arm regions, reflecting an engaged-head and open-arm configuration. The Nse3 subunit secures the DNA from above, while the hook-shaped Nse4 kleisin forms a scaffold connecting DNA and all other subunits. The Smc5/6 DNA clamp shares similarities with DNA-clamps formed by other SMCs but also exhibits differences that reflect its unique functions. Mapping cross-linking mass spectrometry data derived from DNA-free Smc5/6 to the DNA-bound Smc5/6 structure identifies multi-subunit conformational changes that enable DNA capture. Finally, mutational data from cells reveal distinct DNA binding contributions from each subunit to Smc5/6 chromatin association and cell fitness. In summary, our integrative study illuminates how a unique SMC complex engages DNA in supporting genome regulation.

Structural maintenance of chromosomes (SMC) complexes are essential genome regulators in both prokaryotes and eukaryotes. In eukaryotes, the cohesin and condensin SMC complexes organize DNA, while the Smc5/6 complex (referred to as Smc5/6) directly regulates DNA replication and repair (1). At the structural level, SMC complexes share similarities while possessing unique attributes (1). Each complex contains a pair of SMC subunits and a set of non-SMC subunits. The SMC subunits define the tripartite filamentous architecture of the complex: their approximal 50-nm long coiled coil arm region connects their dimerized hinge and adenosine triphosphatase (ATPase) head regions (1). A non-SMC kleisin subunit uses its N- and C-terminal domains to link the head of one SMC to the head-proximal arm region (neck) of another SMC, forming a trimeric SMC-kleisin structure. In cohesin and condensin, two large U-shaped HEAT (Huntington, elongation factor 3, PR65/A, TOR) repeat HAWK (HEAT proteins associated with kleisins) subunits attach to the middle region of the kleisin. By contrast, the Smc5/6 kleisin (Nse4) binds to smaller WH (winged helix)-containing KITE (kleisin interacting tandem WH elements) subunits (Nse1 and Nse3) (2).SMC-mediated functions depend on interactions with DNA. Recent cryogenic electron microscopy (cryo-EM) structures of DNA-bound cohesin and condensin revealed that their HAWK subunits and the SMC head-neck regions form a clamp to enclose a single DNA double helix (3–7). DNA clamping can be critical for cohesin and condensin to extrude DNA loops for chromatin folding (5, 7–9). DNA loop extrusion additionally requires arm bending at a region called the elbow, which is found in both cohesin and condensin (5, 7–9). By contrast, a lack of arm bending in Smc5/6 was suggested by negative stain EM and cross-linking mass spectrometry (CLMS) data (10–14). Since Smc5/6 does not contain HAWK proteins nor shows arm-bending, it has remained unclear how Smc5/6 engages DNA to accomplish its multiple functions.Here we address the molecular mechanisms by which this unique SMC complex binds DNA using an integrative approach, coupling a cryo-EM-based structural characterization with CLMS analyses and functional investigation. Our atomic structure of a DNA-bound Saccharomyces cerevisiae Smc5/6 complex reveals that the head-neck Smc5-6 regions and the Nse1-3-4 subcomplex together form a clamp entrapping the DNA helix. The structure further reveals protein subunit folds and association, as well as how the subunits collaborate to entrap DNA. Comparison of CLMS analyses of DNA-free Smc5/6 with the structure of the DNA-bound Smc5/6 unveils large scale, multi-subunit conformational changes that enable Smc5/6 to encircle DNA. Finally, our mutational data suggest distinct contributions from each of the DNA binding regions to Smc5/6 chromatin association and cellular fitness. Comparison of our findings with those of other SMCs reveals that diverse SMC complexes use a similar DNA clamping strategy despite structural differences, and that Smc5/6 possesses unique features distinct from cohesin, condensin, and prokaryotic SMCs. Our work lays the foundation for an in-depth understanding of how Smc5/6 fulfills unique roles in genome protection.     

新型冠状病毒肺炎后潜水员适潜性评估

新型冠状病毒肺炎（COVID?19）自2019年底爆发以来,对人类生命健康造成了极其严重的危害。作为一种呼吸系统疾病,COVID?19对全身几乎所有器官都会产生影响,其中最主要的受累器官为肺和心脏。随着COVID?19 “康复”患者数量不断增加,越来越多的证据表明,因COVID?19而住院治疗得到“康复”的患者中有相当大比例的人群存在着后遗症,主要表现为呼吸系统和心血管系统的症状。对于潜水员,COVID-19后运动耐受、心肺功能的恢复对于其适潜性具有重要的影响。一些组织和机构对于潜水员COVID-19后的适潜性评估,发布了指南。本文对COVID-19后呼吸和心血管后遗症以及相关的适潜性评估方案进行简要介绍,并基于已有的相关要求和我国实际,初步提出我国潜水员COVID-19后的适潜性评估要求。