三种基牙材料对铸造玻璃瓷冠碎裂影响的研究

目的:研究不同种类和强度基牙材料与瓷冠破折碎裂的内在关系.方法:选用计算机建立上颌中切牙的三维有限元模型,模拟陶瓷层、牙本质、核桩等结构.分析在天然齿基牙、钴铬合金基牙及复合树脂基牙情况下,铸造玻璃陶瓷全冠的瓷层内及残余牙本质的应力分布情况.结果:高弹性模量的钴铬合金能够降低瓷层及残余牙本质内的最大主应力和最小主应力峰值,防止瓷层破折碎裂;而弹性模量与牙本质相近的复合树脂桩降低应力峰值的作用不明显.结论:对于有牙髓活力的牙本质基牙,尽量保存牙髓活力后行全冠修复.对于行根管治疗术后的无髓牙,进行核桩冠修复时,采用高弹性模量的高熔合金,尽量避免使用弹性模量较小的复合树脂核.     

社区公共卫生人才岗位胜任力要素重要性分析

目的 分析社区公共卫生人才岗位胜任力各要素的重要程度,为公共卫生人才队伍建设与培养提供数据与方法学支持。方法 2020年9至10月,选取25位咨询专家,采用区间值犹豫模糊熵法,对确立的岗位胜任力各要素进行重要性分析。利用Excel 2013和SPSS 25.0对数据进行计算。结果 社区公共卫生人才岗位胜任力要素一级指标中,重要性排序为职业素养（0.207）、专业知识与技能（0.204）、整合性思维（0.200）、个人特质（0.199）、职业基本能力（0.191）;二级指标中,重要性排序前3位的为批判性思维（0.105）、系统性思维（0.095）、公共卫生知识技能（0.044）。结论 以职业道德为主的隐性职业素养、以批判性思维为主的公共卫生整合性思维、以公共卫生知识技能为主的专业知识与技能等岗位胜任力要素应予以重点关注。     

Elastofibroma dorsi has distinct cytomorphologic features, making diagnostic surgical biopsy unnecessary: cytomorphologic study with clinical, radiologic, and electron microscopic correlations

Elastofibroma dorsi (EFD) is a relatively rare soft tissue mass, probably of reactive nature. The lesion is typically located near the inferior margin of the scapula or between the inferior part of scapula and the chest wall in elderly women. Although location of the tumor together with the age/sex of the patients and radiologic findings is often suggestive of the diagnosis, tissue examination has been considered necessary to confirm the diagnosis. Although the histologic features of EFD are well known, there are only four single case reports of the cytologic findings in the English language literature. We describe the cytologic features of EFD in five patients with correlations to clinical, radiologic, histologic, and electron microscopic findings. The current study suggests that the fine-needle aspiration (FNA) features are highly diagnostic, permitting a firm diagnosis of EFD in a typical clinical setting and eliminating the need for preoperative histologic examination.     

心脏螺旋波演化与驱动的计算机实验

我们利用FitzHugh-Nagumo(FHN)类型方程,对二维心肌可激媒质系统螺旋波(Spiral wave,SW)的形成、演化和控制进行了数值模拟,主要有以下研究结果:(1)改变系统的可激性,不会影响SW的激发区宽度,却改变SW的自转周期和旋波核的大小;当可激性达到某一极限值时,SW的自转周期与旋波核的半径趋于无穷大,系统不再出现SW。(2)对SW的均匀近共振小电流驱动,可以引导旋波头(Spiral wave tip,SWT)的漂移运动;当驱动频率接近SW的自转频率时,SWT会沿着圆周漂移,当驱动频率达到共振频率时,SWT会沿着直线漂移。     

C基因型乙型肝炎病毒前C区及基本核心启动子突变与疾病进展的相关性研究

目的探讨HBV前C区（PreC）及基本核心启动子（BCP）突变与慢性乙型肝炎病毒（HBV）感染者疾病进展的关系。方法收集88例慢性HBV感染者血清标本，包括36例无症状携带者（其中24例为HBV携带者，12例为HBsAg携带者）、36例慢性乙型肝炎（慢性乙肝）和16例肝硬化患者。所有标本均经型特异性引物PCR法鉴定为HBVC基因型，并用巢氏PCR法扩增HBVPreC和BCP基因片段，用PCR产物直接测序法测序，然后用ClustalW1．8软件进行序列分析。结果在50例HBeAg阳性患者中，无症状携带者、慢性乙肝和肝硬化组的T1762／A1764双突变率和T1846突变率分别为12．5％、42．1％、100％和0％、5．3％、28．6％，差异均有统计学意义（P值分别为0．03和0．02）。在38例HBeAg阴性HBV感染者中，无症状携带者、慢性乙肝和肝硬化组的T1762／A1764双突变率分别为16．7％、58．8％和66．7％，差异无统计学意义（P=0．08）。肝硬化组的C／G1753突变率显著高于无症状携带者及慢性乙肝组（分别为55．6％、8．3％、11．8％，P=0．01），其A1896突变率也高于无症状携带者组（分别为55．6％、8．3％，P=0．01）。结论HBVT1762／A1764双突变与C基因型HBV慢性感染者的疾病进展有关。     

An enzyme-linked immunosorbent assay (ELISA) for the measurement of antibodies to different parts of the gram-negative lipopolysaccharide core region

Bovine serum albumin was complexed with the core antigens of either Escherichia coli J5 LPS, Salmonella minnesota R595 LPS or E. coli lipid A. These core-BSA complexes were used for solid-phase coating in ELISAs for anti-core antibodies. Antibodies, binding to various parts of the core region were easily quantified in a single experimental set-up, which was hitherto not possible. The ELISA has only 3 incubation steps and is not costly as only moderate amounts of the core antigens (i.e., 1 microgram per test) were needed for coating. The sensitivity proved to be excellent and the complexes were biologically fully active (compared to native, smooth LPS), which make them suitable for the screening (after fusion) of monoclonal anti-core antibodies. Another possible application is the large-scale screening of blood-bank sera in order to find samples with a high anti-core antibody content.     

An electron microscopic and immunohistochemical study of Merkel cell carcinoma

Two cases of Merkel cell carcinoma (MCC) were examined by electron microscopy and immunohistochemistry. Histologically, tumor cells, which extended from the dermis into the subcutis, showed anastomosing bands with partial trabecular pattern. The ultrastructural study showed tumor cells in case 1 with numerous neurosecretory granules. The number of granules in case 2, however, was smaller compared with that in case 1. Perinuclear bundles of filaments were present in case 2, but few bundles were observed in case 1. By immunohistochemistry, cytokeratin (CK)-8, -18, -19, and -20 and epithelial membrane antigen were stained positively within tumor cells in both cases. It was interesting that staining patterns of chromogranin A and of neuron-specific enolase were different in the two cases. These data indicated that CK-20 is a useful marker for diagnosing MCC and that ultrastructural and immunohistochemical differences in both cases were the result of phenotypic variation.     

The affinity of anti-HBc antibodies in acute and chronic hepatitis B infection.

Antibodies to hepatitis B core antigen (anti-HBc) are found in the sera of all individuals infected with hepatitis B virus. A role for these antibodies has been suggested in determining the outcome of infection. In this study, the affinity of anti-HBc antibodies in asymptomatic virus carriers was compared with that of antibodies present in the sera of patients with chronic liver disease. Persistently infected individuals with no evidence of clinical disease were found to have anti-HBc antibodies of greater affinity, compared with the chronic liver disease group. Sera from patients with chronic hepatitis contained high levels of low-affinity antibody whereas antibody levels in asymptomatic carriers were significantly lower. These findings are discussed in relation to the predicted role of anti-HBc antibodies in mediating hepatitis B virus-related hepatocellular injury.     

C基因截短的HBV复制与包装

目的 探讨C基因截短型HBV变异体的复制与包装。方法 采用分子克隆、人工定点突变等技术构建C基因截短型HBV变异体质粒，用脂质体法转染HepG2细胞，提取细胞内及培养上清液中DNA分别进行Southem杂交，PCR及实时定量荧光PCR分析。结果 经DNA测序及酶切鉴定证实C基因截短型HBV质粒载体构建成功；C基因截短型HBV为复制缺损型，与辅助质粒共转染HepG2细胞，可在细胞内及培养上清液中检测到HBV各种DNA构型；DNA定量分析提示C基因截短型HBV的包装效率较野生型HBV提高3～40倍。结论 C基因截短型HBV变异体为复制缺损型，单独转染后不能在肝细胞内包装与复制，但在缺失包装信号ε的相应辅助病毒辅助下可有效复制并包装成子代病毒颗粒分泌到胞外，且包装效率大大提高。     

Postoperative spindle cell nodule of the breast: Pseudosarcomatous myofibroblastic proliferation following endo‐surgery

Despite the frequent use of fine‐needle aspiration, core biopsy and surgery, postoperative spindle cell nodule (PSCN) is a rare pathological complication that may be diagnostically treacherous. Presented herein is the case of a 52‐year‐old woman who developed a 7 mm mammary nodular lesion 66 days after removal of an area of columnar cell hyperplasia involving cellular and architectural atypia, performed with the Mammotome Breast Biopsy System. The lesion was highly cellular and composed of intersecting fascicles of plump spindle cells with blunt‐ended elongated nuclei and nucleoli easily visible. Interspersed mononuclear cells and hemosiderin‐laden macrophages were evident. PSCN is a reactive, benign myofibroblastic proliferation. Differential diagnosis includes benign and malignant spindle cell lesions of the breast. Recognition of this reactive lesion will avoid overdiagnosis of spindle cell malignant tumor. Attention to clinicopathological and histological features should result in accurate recognition of this lesion.