Response of left ventricular diastolic filling to graded exercise relative to the lactate threshold

Summary During incremental exercise, the left ventricular ejection fraction increases up to the intensity of the anaerobic threshold and tends to level off at higher exercise intensities. Since there is a correlation between the response of peak filling rate and ejection fraction to exercise, this study was conducted to determine whether the response of left ventricular diastolic function is similar to the response of systolic function relative to lactate threshold. Twelve healthy men performed two exercise tests on a cycle ergometer. In the first test, lactate threshold and maximal power output were determined. In the second exercise test, gated radionuclide ventriculography was performed at rest, at the lactate threshold intensity, and at peak exercise to measure ejection fraction and peak filling rate. Ejection fraction increased significantly from rest [mean (SD): 62 (5)%] to lactate threshold [76 (7) %] and did not change significantly from lactate threshold to peak exercise [77 (7)%]. Likewise, peak filling rate (normalized for stroke counts) increased from resting [6.1 (0.9)V _s · s^–1] to lactate threshold [9.4 (1.8)V _s · s^–1] and did not change significantly from lactate threshold to peak exercise [9.6 (2.9)V _s · s^–1]. There was no correlation between the change in peak filling rate and the change in ejection fraction from rest to lactate threshold. Thus, during incremental exercise, left ventricular diastolic function responds qualitatively similar to systolic function.     

Chimeric Fc receptors identify immunoglobulin-binding regions in human FcγRII and FcϵRI

FcγRII and Fc?RI are functionally distinct cell surface receptors for immunoglobulin (Ig); FcγRII binds IgG with low affinity, whereas Fc?RI binds IgE with high affinity, yet they are homologous in structure and sequence having extracellular regions containing two Ig-like domains with 38% amino acid identity. Chimeric receptors derived from human FcγRII and FcγRI were produced by exchanging homologous regions of the two receptors to define binding region(s) for IgG in FcγRII and IgE in Fc?RI. Firstly, a chimeric form of the Fc?RI α chain was produced by replacing the transmembrane region and cytoplasmic tail with that of FcγRII. This mutant α chain could be expressed on the cell surface independently of associated β and γ subunits, and retained high-affinity IgE binding, indicating that the extracellular region of the FcγRI α chain is sufficient for high-affinity IgE binding. Secondly, to identify the role of the individual domains in Fc binding of both FcγRII and FcγRI, chimeric receptors were generated by exchanging the first extracellular domains between FcγRII and the α chain mutant and used to demonstrate that the second extracellular domain of both receptors contains region(s) directly involved in Ig binding. Additional chimeric receptors were constructed to localize the Ig interactive regions in domain two of FcγRII and FcγRI; these identified a single region of IgG binding in FcγRII located between residues Ser¹³⁶ to Val¹⁶⁹, and at least three independent IgE binding regions in the FcγRI α chain, between residues Trp⁸⁷ to Lys¹²⁸, Tyr¹²⁹ to Asp¹⁴⁵, and Ser¹⁴⁶ to Val¹⁶⁹.     

Evaluation of quantitative aerosol techniques for use in bronchoprovocation studies

To investigate airway physiology by use of inhaled aerosols, it is frequently necessary to measure the actual amount of material deposited on the airway wall as well as the site of particle deposition. To satisfy these needs, radiolabeled aerosols and gamma camera techniques have been used to measure regional deposition of inhaled particles. To make quantitative measurements of the amount deposited, previous investigators have used a "phantom" technique to indirectly calibrate the gamma camera for the attenuation of gamma rays through the lungs and chest wall. For this calibration, the phantom is a simulated lung containing a known amount of radioactivity. Radioactive counts emitted from the phantom are assumed to be attenuated in the same manner as the intact human lung. The present article describes a technique to determine directly the amount of inhaled aerosol deposited in the lung and simultaneously to calibrate the gamma camera for each individual subject. We used right angle light scattering and a gamma camera to measure individual values of the deposition fraction (DF) of inhaled aerosol deposited in the lung and the coefficient of attenuation (AC) of gamma rays in normal and obstructed lungs of human subjects. Radiolabeled monodisperse aerosols 1 and 2 microns in diameter were used. Knowledge of the activity of the inhaled aerosol (microcurie per liter), the volume inhaled, and the measured DF determined each subject's AC (counts per minute per microcurie). DF varied by an order of magnitude in normal (0.04 to 0.48) and obstructed (0.16 to 0.75) of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

2015—2019年北京市食源性致泻大肠埃希氏菌感染病例流行特征分析

目的分析2015—2019年北京市食源性致泻大肠埃希氏菌(diarrheagenic Escherichia coli,DEC)感染病例的流行病学特征和发病规律,为制定相应的防控策略与措施提供科学依据。方法收集2015—2019年北京市36家食源性疾病主动监测医院腹泻病例的粪便或肛拭子标本及其个人信息,采用χ^(2)检验对率或构成比进行比较。结果共收集27619份病例标本,其中有2485份为DEC阳性病例,检出率为9.00%,不同分型中肠产毒性大肠埃希菌检出率最高,为3.10%,其次为肠聚集性大肠埃希菌,检出率为3.02%。不同年龄组DEC检出率差异有统计学意义(χ^(2)=32.923,P<0.001),20~39岁年龄组DEC检出率最高,为9.81%,40~59岁年龄组感染肠产毒性大肠埃希菌高于其他年龄组,0~5岁年龄组肠致病性大肠埃希菌的检出率最高。时间分布上,第三季度为高发期,不同季度间DEC检出率差异有统计学意义(χ^(2)=606.032,P<0.001)。空间分布上,远郊的DEC检出率最高,且城区、近郊和远郊的DEC检出率差异有统计学意义(χ^(2)=28.034,P<0.001),肠产毒性大肠埃希菌的检出主要分布在城区和近郊,肠聚集性大肠埃希菌主要分布在远郊。结论2015—2019年北京市食源性DEC的检出率呈逐年上升趋势,应在夏秋高发季节针对重点人群积极开展防控工作。     

2018—2020年徐州市食源性疾病监测分析

目的 分析徐州市2018—2020年食源性疾病哨点医院主动监测结果,了解该地区食源性疾病流行特征。方法 收集2018—2020年徐州市食源性疾病哨点医院监测的病例信息,并对部分病例的粪便样本进行病原学检测。结果 3年共监测食源性疾病病例7 548例,其中25～45岁年龄组占比最高(26.81%);6—9月为发病高峰;肉与肉制品(20.72%)为主要的可疑暴露食品;可疑食物进食场所主要为家庭(80.49%);农民(26.75%)和散居儿童(24.95%)病例构成比较高。共采集1 835份腹泻病例粪便样本,其中诺如病毒检出率最高为(4.69%)。结论 徐州市食源性疾病高发期为6—9月,具有明显的季节性,好发于家庭,肉与肉制品为主要暴露食品,感染患者集中在>25～45岁年龄组,诺如病毒感染率较高。     

一种复合微生物菌肥对穿心莲生长、品质及土壤性质的影响

目的：研究一种微生物复合菌肥对穿心莲生长、品质及土壤性质的影响,旨在为穿心莲栽培生产中微生物复合菌肥的应用提供依据。方法：通过盆栽的共5个处理试验,CK（不施肥）组、A处理（施化肥）组、B处理（施微生物菌肥,施用量为2.5 g·kg-1土）组、C处理（施微生物菌肥,施用量为7.5 g·kg-1土）组、D处理（施微生物菌肥,施用量为12.5 g·kg-1土）组,研究一种复合微生物菌肥对穿心莲的农艺性状、有效成分含量及根际土壤细菌、放线菌、真菌的数量和土壤理化性质的影响。结果：施加一定量的复合微生物菌肥,穿心莲的株高、叶片数、叶面积、地上部、地下部鲜重较CK组和A处理组显著升高,不同生长期有差异。复合微生物菌肥对穿心莲内酯、脱水穿心莲内酯、新穿心莲内酯及14-去氧穿心莲内酯含量影响有差异,与CK组、A处理组比较,C处理组的穿心莲内酯分别明显升高26.13%、13.23%(P<0.05);新穿心莲内酯的含量随微生物菌肥施加量的增加而增加,在D处理组下的效应最显著,与CK组、A处理组比较,分别明显升高9.06%、50.33%(P<0.05);B处理组的14-去氧穿心莲内酯较A处理组...     

杜仲及其有效成分治疗膝骨关节炎的作用机制研究现状

膝骨关节炎（KOA）是中老年常见的退行性关节疾病,发病率随着人口老龄化程度加深及肥胖人群增加而不断增加,严重影响患者健康及日常生活。目前采用的非甾体类抗炎药、软骨保护类药物、阿片类镇痛药等对症治疗手段作用有限,且药物不良反应明显。杜仲是治疗KOA常用且有效的中药之一,但其作用机制和药效物质基础尚未明确,限制了其在临床更为广泛的运用。杜仲在KOA治疗领域的有效成分主要为环烯醚萜类（京尼平苷、杜仲苷/桃叶珊瑚苷）、木脂素类（松脂醇二葡萄糖苷）、黄酮类（槲皮素、紫云英苷、黄芩素、金丝桃苷、山柰酚）、苯丙素类（绿原酸）、杜仲多糖等化合物,他们主要通过丝裂原活化蛋白激酶、核转录因子-κB、磷脂酰肌醇3-激酶/蛋白激酶B及等Janus激酶1/信号转导和转录激活因子3等信号通路,来调节炎性因子水平、抗氧化应激反应、保护软骨细胞、平衡细胞外基质合成与降解等,控制KOA病情进展。该文对杜仲及其有效成分在KOA治疗方面的作用机制进行了综述,以期为KOA新药研发提供理论依据。     

中药调控膝骨关节炎相关信号通路的研究进展

随着中医药对膝骨关节炎（KOA）研究的不断深入,现代学者发现诸多中药可从分子层面干预信号通路延缓膝骨关节炎的进展。文中所述中药及其活性成分在干预膝骨关节炎的机制中与信号通路有着密切关系。中药及有效成分可在不同信号通路的传导下调控相应的靶向分子水平,抑制软骨炎性因子、细胞凋亡、软骨基质降解及促进软骨细胞自噬,以达到减轻滑膜炎性水肿和延缓软骨退变的目的。现对国内外中药干预KOA的研究进行系统性总结：黄芩素等可通过阻断磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/Akt）信号通路,减少软骨细胞炎性因子、凋亡及促进自噬;山茱萸新苷Ⅰ等成分降低Janus激酶2/信号转导和转录激活因子3（JAK2/STAT3）通路磷酸化活性改善滑膜炎症、延缓软骨基质退变;丹酚酸A等中药活性成分可通过抑制核转录因子-κB（NF-κB）通路磷酸化,减轻炎症与软骨基质降解;大黄素等有效成分可降低Wnt/β-连环蛋白（Wnt/β-catenin）通路活性,抑制胶原蛋白与蛋白多糖分解;肉豆蔻苷等通过阻断p38丝裂原活化蛋白激酶（p38 MAPK）信号传导,抑制细胞凋亡;木通皂苷D等可增强核因子E₂相关因子2/血红素加氧酶1（Nrf2/HO-1）通路活性,抑制软骨细胞氧化应激;牛膝总皂苷等通过增强转化生长因子-β（TGF-β）/Smad信号传导,减少软骨基质降解;藏红花素通过激发河马/Yes相关蛋白（Hippo/YAP）活性抑制软骨炎症与凋亡因子增加;川芎嗪阻断Notch通路改善软骨细胞形态与异常;齐墩果酸等通过发挥雌激素信号通路,减轻软骨基质破坏与退变。以上总结旨在为今后开展KOA临床与实验研究提供借鉴。     

早期被动操结合主动运动训练对早产/低体重儿体格及智能发育的影响研究

目的 分析早期被动操结合主动运动训练对早产/低体重儿体格及神经心理发育的影响,为其在早产/低体重儿体格及神经心理发育中的促进作用提供循证依据。方法 选取 2017年7月—2019年7月在金安区妇幼保健院高危儿门诊建档的218名早产/低体重儿作为研究对象,根据家长是否按照要求坚持对早产/低体重儿进行早期(校正6月龄前)被动操及主动运动训练的频率和持续时间不同进行分组,采用Gesell发育量表对研究对象进行神经心理发育评估,比较各组校正6月龄、12月龄时体格发育及Gesell评分情况。结果 早期被动操及主动运动训练频率越高及持续时间越长,早产/低体重儿在校正6月龄与12月龄时其体格测量值及智能发育商数越高,差异有统计学意义(P＜0.05)。与训练频率≤1 d/周组相比,除校正6月龄头围外,训练频率2～3 d/周组及≥4 d/周组的早产/低体重儿在校正6月龄及12月龄时体重、身长和头围测量值及适应能力、大运动、精细动作能区发育商数更高(P＜0.05);与持续时间0～2个月组相比,持续时间5～6个月组的早产/低体重儿在校正6月龄及12月龄时体重、身长及适应能力、精细动作、社交行为等能区发育商数更高(P＜0.05)。结论 家长坚持给予早产/低体重儿做被动操及主动运动训练对其体格和神经心理发育具有一定的促进作用。     

Active Case Finding of Current Bornavirus Infections in Human Encephalitis Cases of Unknown Etiology,Germany, 2018–2020

Human bornavirus encephalitis is a severe and often fatal infection caused by variegated squirrel bornavirus 1 (VSBV-1) and Borna disease virus 1 (BoDV-1). We conducted a prospective study of bornavirus etiology of encephalitis cases in Germany during 2018–2020 by using a serologic testing scheme applied along proposed graded case definitions for VSBV-1, BoDV-1, and unspecified bornavirus encephalitis. Of 103 encephalitis cases of unknown etiology, 4 bornavirus infections were detected serologically. One chronic case was caused by VSBV-1 after occupational-related contact of a person with exotic squirrels, and 3 acute cases were caused by BoDV-1 in virus-endemic areas. All 4 case-patients died. Bornavirus etiology could be confirmed by molecular methods. Serologic testing for these cases was virus specific, discriminatory, and a practical diagnostic option for living patients if no brain tissue samples are available. This testing should be guided by clinical and epidemiologic suspicions, such as residence in virus-endemic areas and animal exposure.