Partial purification and characterization of anhydrotetracycline oxygenase of Streptomyces aureofaciens

Anhydrotetracycline oxygenase was purified both by affinity chromatography and by hydrophobic interaction chromatography. Molecular weight of anhydrotetracycline oxygenase was determined to be 115,000 by Sephadex G-200 gel filtration. Using preparative isoelectric focusing the isoelectric point of the enzyme was estimated to be 5.3. The enzyme showed a sensitivity to thiol-specific inhibitors. During the hydrophobic interaction purification step, the activity dropped considerably. Reactivation occurred when a heat treated crude extract was added to the reaction mixture.     

Structure-intestinal transport and structure-metabolism correlations of some potential cancerostatic pyrimidine nucleosides in isolated rat jejunum

Summary Both transport and biotransformation processes for a series of pyrimidine nucleobases, ribonucleosides, 2-deoxyribonucleosides, and acetyl and 5-substituted derivatives of the cancerostatic agent araC were studied in the isolated everted rat jejunum with a continuous perfusion technique. Metabolic alterations during penetration were assessed by HPLC. 5-Halogeno and 5-deoxy derivatives of cytosine nucleosides exhibited higher transport rates and higher stability towards the deamination reaction than did unsubstituted derivatives. Octanol-buffer partition coefficients were estimated for the study compounds, and fragmental constants for the sugar moieties of nucleosides were assessed. With the present study compounds there was no correlation between lipophilicity and transport rate, as previously reported, but there was a correlation between lipophilicity and metabolic alteration of araC derivatives (r=0.99, n=5).     

2005-2019年理塘县法定传染病疫情分析

目的了解理塘县近15年法定传染病疫情形势及流行特征,为政府制定防控措施提供科学依据。方法对2005—2019年理塘县法定传染病疫情进行描述性流行病学分析。采用ArcGIS 10.3软件绘制各乡镇发病情况分布图,SPSS 21.0软件进行χ²检验、趋势性χ²检验。结果2005—2019年理塘县共计报告甲乙丙类传染病21种6154例,年均发病率为644.33/10万,发病呈上升趋势。死亡37例,年均死亡率3.87/10万,病死率0.60%。呼吸道传染病发病最高(341.12/10万);发病前3位的病种为肺结核(271.91/10万)、乙肝(103.24/10万)及包虫病(67.22/10万);肺结核、其他感染性腹泻病、艾滋病/HIV、梅毒发病呈上升趋势。3月、9月分别出现1次发病高峰;20~29岁、30~39岁和10~19岁组发病居前3位;男女性别比为1.24∶1;发病以农民、牧民及学生为主。结论2005-2019年理塘县法定传染病发病率较高且呈上升趋势,应针对高发传染病、上升趋势明显的传染病、重点人群进行分析研究,采取针对性措施控制疫情。     

颅脑肿瘤术后并发静脉血栓栓塞症危险因素的Meta分析

目的明确颅脑肿瘤术后患者发生静脉血栓栓塞症(VTE)的危险因素。方法检索中国知网、万方、维普、中国生物医学文献、PubMed、The Cochrane Library、Web of Science、EMbase等数据库建库至2021年11月1日颅脑肿瘤术VTE危险因素的队列研究或病例对照研究。由两名研究人员独立进行文献筛选、资料提取以及文献质量评价。使用RevMan 5.4软件对纳入文献进行Meta分析。结果共纳入14篇文献,合计样本量40 552例,发生VTE1 801例。Meta分析结果显示,年龄＞45岁、术前D-二聚体升高、肥胖、女性、术前日常生活活动能力处于依赖状态、术前呼吸机依赖、术前曾患脓毒血症、高级神经胶质瘤、手术时间＞3.05 h、术后D-二聚体升高、术后下肢运动功能障碍、术后卧床不起、术后并发尿路感染为颅脑肿瘤术后患者发生VTE的危险因素。结论颅脑肿瘤术后VTE发生与多种因素有关。建议构建颅脑肿瘤术后VTE风险预测模型,关注高风险人群,落实规范化静脉血栓风险评估,注重血栓评估过程管控。     

生物医学科技论文存在的利益冲突问题及其应对措施

【目的】 探讨生物医学科技论文存在的主要利益冲突(Conflict of Interest, COI)问题及其应对措施。【方法】 通过检索Retraction Watch 数据库,收集2016—2021年生物医学期刊中因COI相关问题被撤销、更正或关注的95篇论文为研究对象。回顾性调查论文及其处理(撤稿、更正或关注)声明的主要特征、存在的COI问题及处理措施。【结果】 本研究纳入的95篇论文中,72篇被撤销,23篇被更正或关注。论文存在的主要COI问题包括COI披露不完整(46.3%)、确实存在COI(18.9%)、对已披露COI的完整性存在质疑(12.6%)、潜在的COI披露不完整(12.6%)、COI披露错误(5.3%)等;具体COI表现为作者与企业(42.1%)、其他研究者(9.7%)、其他作者(7.0%)、研究机构(6.1%),以及期刊编辑或审稿人(5.3%)等之间存在的潜在COI或COI。【结论】 生物医学期刊论文发表过程中存在多种COI问题,并且表现形式多样。建立并完善COI相关编辑政策,可预防COI相关问题的发生,从而减少发表偏倚。     

基于UPLC-Q-TOF-MS的建昌帮砂仁陈皮制熟地黄适宜炮制时间分析

目的：研究建昌帮砂仁陈皮制熟地黄炮制过程中差异代谢物和苷类分解产物还原糖的相对含量变化,为揭示该特色品种的炮制原理奠定基础。方法：以建昌帮砂仁陈皮制熟地黄的0～54 h炮制过程样品为研究对象,运用超高效液相色谱-四极杆-飞行时间质谱法（UPLC-Q-TOF-MS）检测其次级代谢产物,以0.1%甲酸水溶液（A）-乙腈（B）为流动相进行梯度洗脱（0～1 min,1%～3%B;1～10 min,3%～9%B;10～15 min,9%～12%B;15～22 min,12%～18%B;22～31 min,18%～24%B;31～35 min,24%～100%B;35～36 min,100%～5%B;36～40 min,5%～1%B;40～45 min,1%B）,柱温40℃,进样量3μL,流速0.3 mL·min-1;运用电喷雾离子源（ESI）,在负离子模式下进行扫描并采集MS数据,扫描范围m/z 50～1 250,利用PeakView 1.2进行数据分析,结合文献信息及化学成分数据库对砂仁陈皮制熟地黄化学成分进行鉴定;MS数据通过MarkerView 1.2归一化处理后应用多元统计分析方法找出差...     

Can Policy Promote Adoption or Outcomes of Evidence-based Prevention Programming?: a Case Illustration of Positive Behavioral Interventions and Supports

Prevention Science - This study examined the impact of a state policy requiring that any school with a habitual truancy rate of 8% or higher to be trained in Tier 1 school-wide Positive Behavioral...     

户外活动时间与学龄前文化课学习情况对中小学生视力不良的交互作用

目的 分析户外活动时间与学龄前参加文化课学习情况的交互作用与中小学生视力不良的关系,为制定防控中小学生视力不良的策略和措施提供科学依据。方法 采用分层整群随机抽样法于2018年9-11月在湖南省抽取8 467名小学四年级到高中三年级学生进行体格检查和问卷调查。相乘交互作用建立多因素Logistic回归模型,并计算交互作用超额危险度(RERI)、交互作用归因比(API)及交互作用指数 S (Index S)探讨户外活动时间与学龄前文化课学习对视力不良的相加交互作用。结果 8 467名调查对象中视力不良检出人数为5 612名,检出率为66.28%。学龄前参加过文化课学习者,视力不良的发生风险是不参加学习者的1.500倍(95%CI:1.331~1.689,P<0.001),每日户外活动<2 h的学生发生视力不良的风险是每日户外活动≥2 h者的1.247倍(95%CI:1.103~1.409,P<0.001)。户外活动时间与学龄前文化课学习的交互作用项具有统计学意义(P_交互=0.003)。在调整相关因素后,户外活动时间与学龄前文化课学习的RERI、API、Index S分别为0.529、0.310、3.973。结论 中小学生户外活动时间、学龄前文化课学习均与视力不良发生风险相关,并两者对视力不良有交互作用。因此,应加强学龄前儿童的户外活动,以预防视力不良发生。     

Waning Antibody Responses in Asymptomatic and Symptomatic SARS-CoV-2 Infection

We investigated the kinetics of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies in 7 asymptomatic persons and 11 patients with pneumonia. The geometric mean titer of neutralizing antibodies declined from 219.4 at 2 months to 143.7 at 5 months after infection, indicating a waning antibody response.     

Surveillance of COVID-19–Associated Multisystem Inflammatory Syndrome in Children,South Korea

A concerning development during the coronavirus disease pandemic has been multisystem inflammatory syndrome in children. Reports of this condition in East Asia have been limited. In South Korea, 3 cases were reported to the national surveillance system for multisystem inflammatory syndrome in children. All case-patients were hospitalized and survived with no major disease sequelae.