简介:[摘要] 根据问题与条件间的关系,恰当地运用辅助构造,会把问题转化或更为直观、简单。运用这种方式比用其它方法来得直接、快捷。辅助构造工具可以构造图形、构造函数、构造模型、构造方程。
简介:AbstractObjective:The coronavirus disease 2019 (COVID-19) epidemic resulting from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has still spread globally. The occurrence of the Delta variant, which is more infectious and spreads faster than earlier forms of the virus that causes COVID-19, makes infection prevention more challenging. Therefore, this study aimed to gain a comprehensive insight into the transmission routes of SARS-CoV-2 for curbing the propagation of SARS-CoV-2 in human populations.Methods:We studied a prospective cohort of 576 patients admitted consecutively to the First Affiliated Hospital of Guangzhou Medical University from January 21 to June 8, 2020. These patients were chosen based on their similar clinical phenotypes or imaging findings. There were 21 (3.6%) laboratory-confirmed COVID-19 patients (16 severe and 5 mild cases) and 555 non-COVID-19 patients. The antibody response and routes and duration of viral shedding were systematically evaluated in serial clinical specimens. Moreover, SARS-CoV-2 RNA was also detected in a mouth rinse, urine, and tear samples. This study was approved by the Medical Ethical Committee of The First Affiliated Hospital of Guangzhou Medical University (approval No. 2020-77).Results:SARS-CoV-2 mainly existed in sputum, nasal and throat swabs, and feces samples. Virus latency was longer in sputum and feces samples than in nasopharyngeal samples. IgG antibody response in respiratory samples was related to disease severity. Although droplets and aerosols are the major transmission routes for COVID-19, covert routes of transmission from asymptomatic patients, contaminated surfaces, and wastewater are also of interest.Conclusion:Our findings provide a solid foundation for developing prophylactic measures against SARS-CoV-2.
简介:AbstractThe coronavirus disease 2019 (COVID-19) pandemic was triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a previously unknown strain of coronavirus. To fully understand the consequences and complications of SARS-CoV-2 infections, we have reviewed current literature on coagulation dysfunctions that are related to the disease and vaccination. While COVID-19 is more commonly considered as a respiratory illness, studies indicate that, in addition to respiratory illness, a coagulation dysfunction may develop in individuals after the initial infection, placing them at the risk of developing thrombotic events. Patients who died of COVID-19 had higher levels of D-dimer, a biomarker for blood clot formation and breakdown. Effective treatments for coagulation dysfunctions are critically needed to improve patient survival. On the other hand, antibodies against platelet factor 4 (PF4)/heparin may be found in patients with rare instances of vaccine-induced immunological thrombotic thrombocytopenia (VITT) following vaccination with adenovirus-based vaccines. VITT is characterized by atypical thrombosis and thrombocytopenia, similar to immune-mediated heparin-induced thrombocytopenia (HIT), but with no need for heparin to trigger the immune response. Although both adenovirus-based and mRNA-based vaccines express the Spike protein of SARS-CoV-2, VITT is exclusively related to adenovirus-based vaccines. Due to the resemblance with HIT, the use of heparin is highly discouraged against treating patients with thrombotic thrombocytopenia after SARS-CoV-2 infection or with VITT after vaccination. Intravenous immunoglobulin therapy coupled with anticoagulation is recommended instead. The well-studied anti-PF4 monoclonal antibody RTO, which does not induce pathologic immune complexes in the presence of heparin and has been humanized for a potential treatment modality for HIT, may provide a nonanticoagulant HIT-specific solution to the problem of increased blood coagulation after SARS-CoV-2 infection or the VITT after immunization.
简介:目的:系统评价CYP2C19基因多态性中快代谢型(extensivemetabolism,EM)与中间代谢型(intermediatemetabolism,IM)、慢代谢型(poormetabolizer,PM)基因型对心血管疾病患者服用氯吡格雷低反应的影响程度。方法:电子检索中、英文数据库中服用氯吡格雷的心血管疾病患者中有关CYP2C19*EM与IM+PM相关性的临床研究或观察性试验,检索年限为建库至2016年11月。2名研究者依据纳入标准及评价量表进行文献筛查及数据提取。采用RevMan5.0软件对相关效应指标进行的文献荟萃(Meta)分析。结果:共纳入9篇文献,纽卡斯尔-渥太华量表评分均≥7分,心血管疾病患者共2346例。Meta分析结果显示,心血管疾病患者服用氯吡格雷后,EM与IM+PM基因型携带者发生氯吡格雷抵抗(RR=0.46,95%CI=0.19~1.13)及支架内血栓形成发生率(RR=0.72,95%CI=0.34~1.53)的差异均无统计学意义(P〉0.05),但心血管事件发生率的差异有统计学意义(RR=0.33,95%CI=0.21~0.53,P〈0.05),CYP2C19*IM+PM基因型携带者较CYP2C19*EM基因型携带者可明显增加心血管事件的发生。结论:在服用氯吡格雷的心血管疾病患者中,CYP2C19*IM+PM基因型携带者较CYP2C19*EM基因型携带者更易发生心血管事件,但氯吡格雷抵抗及支架内血栓形成的发生率未见明显差异。因此,建议在服用氯吡格雷或拟行经皮冠状动脉介入治疗患者应先测定CYP2C19基因型突变程度,再考虑是否应用氯吡格雷抗血小板治疗。
简介:目的探讨CYP2C19基因型检测方法及其在安徽省汉族人群中基因多态性的分布.方法在110名汉族健康人的外周血中,应用聚合酶链反应(PCR)-限制性片段长度多态性分析(RFLP)技术,进行CYP2C19等位基因分型研究.结果应用PCR-RFLP技术可准确区分CYP2C19基因型.在110名检测标本中,CYP2C19纯合子强代谢型、杂合子强代谢型和弱代谢型的发生率分别40%、49%和11%.结论PCR-RFLP方法检测CYP2C19基因型特异性高,成熟,稳定;中国安徽汉族人群存在CYP2C19的基因多态性,其弱代谢型的发生率与中国总体发生率基本一致.
简介:摘要:目的 探讨太原地区缺血性脑卒中 汉族 患者 CYP2C19 基因多态性分布情况。方法 选取该院缺血性脑卒中患者 403 例,检测 CYP2C19 基因多态性,统计等位基因及代谢型分布特征,并对比不同区域等位基因及代谢表型分布差异,以及探讨同一地区缺血性脑卒中同冠心病患者的等位基因及代谢表型成分差异。结果 CYP2C19*1 、 CYP2C19*2 、 CYP2C19*3 3 种等位基因频率分别为 45.9 % 、 45.9 % 、 6.45 % ;快代谢型 184 例,发生率 45.9 % ;中间代谢型 170 例,发生率 42.18 % ;慢代谢型 49 例,发生率 12.19 % ;不同性别之间 CYP2C19 基因型及代谢表型差异无统计学意义( P>0.05 ) ; 不同年龄段患者 CYP2C19 基因型及代谢表型差异无统计学意义( P>0.05 ) , 不同地区汉族人群基因型差异有统计学意义( P<0.05 ),不同地区汉族人群代谢表型差异无统计学意义( P>0.05 );太原地区缺血性脑卒中患者同冠心病患者 CYP2C19 基因多态性差异无统计学意义。结论 太原地区缺血性脑卒中患者基因型以 CYP2C19*1/* 1 及 CYP2C19*1/* 2 为主,代谢表型以 快 代谢型为主,可以为氯吡格雷抵抗风险评估,为患者制定个体化抗血小板治疗方案。
简介:目的:应用三维凝胶基因芯片方法研究中国人群CYP2C9与CYP2C19基因多态性,为临床合理用药提供新的技术手段与研究方法。方法:提取207名男性健康志愿者基因组DNA,PCR分别扩增包含CYP2C9*3、*13与CYP2C19*2、*3多态位点目标片段,制备三维凝胶基因芯片,荧光标记探针杂交,芯片扫描并基因分型,用直接测序法对结果进行验证。结果:207人中,11人为CYP2C9*1/*3基因型,1人为CYP2C9*1/*13基因型,1人为CYP2C9*3/*3基因型。2C9*3、*13等位基因发生率分别为2.90%、0.24%,慢代谢型发生率为0.48%。CYP2C19突变杂合子有97人,突变纯合子有26人,2C19*2、*3等位基因发生率分别为32.85%、3.62%,慢代谢型发生率为12.56%。四种等位基因型分布均符合Hardy-Weinberg平衡。结论:三维凝胶基因芯片方法可为临床快速基因分型提供高效平台。CYP2C9与CYP2C19基因在中国人群存在普遍多态性,检测其基因型可有效指导相关临床治疗药物应用,提高药效,降低不良反应。
简介:摘要目的探讨CYP2C9、CYP2C19基因多态性对心脏瓣膜置换术后患者华法林代谢及个体化用药的影响。方法随机选取2012年1月~2015年1月期间我院收治的风湿性心脏病心脏瓣膜置换术后患者120例,均用PCR-荧光探针法对患者CYP2C9*3(A1075C)基因多态性进行检测,从而辅助临床指导患者个体化华法林的使用;检测CYP2C19*2(G681A)和CYP2C19*3(G636A)基因多态性,通过对患者基因分型检测,判定患者的华法林代谢速率类型,从而合理调整药物剂量,提高药物的有效性。结果CYP2C9、CYP2C19基因多态性对华法林血药浓度具有影响;PM、M与EM标准血药浓度比较,差异明显(P<0.05),具有统计学意义。结论CYP2C9、CYP2C19基因多态性对个体华法林代谢存在一定影响,为提高患者个体用药效果提供参考与借鉴。
简介:通过讨论得出一种新的构造地质学观点:⑴板块与板块碰撞造山是靠地震来实现的。当地球某处的能量积聚到一定的极限就会产生地震释放能量;⑵地震时产生地震波,地震波传播同时也传导了地震力。地震力是与地震波的类型相一致,地震力可对应地称为纵波力、横波力、拉夫力和瑞雷力。这些力可以合成或分解为线状力、面状力和体状力;⑶地震时将动能转化为势能,使地体隆升,产生断层和挠褶等。升高的势能又在重力作用下产生新的构造。震力和重力作用是形成地质构造的两大因素;⑷威尔逊旋回不适宜板内造山旋回。板内造山旋回简单地说就是沉积—隆升—剥蚀—夷平。一个大的构造期,实际上是孕育了一个大的地震周期。以此为理论依据,将山西地区显生宙以来大级别的造山-沉积旋回划分为五个。
简介:摘要目的研究分析BD与VAD方案对多发性骨髓瘤的疗效比较。方法将2014年——2016年收治的多发性骨髓瘤76例按照治疗方案的不同分成两组,分别采用BD治疗方案和VAD治疗方案,比较两组患者的治疗效果以及治疗期间毒副反应发生情况。结果BD组患者治疗有效率达到89.47%(34/38),较比VAD组60.53%(23/38)的治疗效果有差异,P<0.05,有统计学意义。BD组患者较VAD组脱发、肝功能损伤、心肌酶谱改变不良反应有差异,P<0.05,有统计学意义。结论多发性骨髓瘤采用BD方案治疗较VAD方案治疗效果明显提高,毒副作用小,患者的耐受度提高,值得临床推广。