两株具有广谱抗菌性的缓征链球菌的安全性评价

目的通过动物实验对分离于健康儿童口咽部的2株缓征链球菌菌株4-2、4-19进行安全性评价,为呼吸道益生菌的制备提供安全依据。方法对SPF级昆明种小鼠灌胃给予含有菌株4-2和4-19的菌液,观察实验动物是否出现死亡、急性毒性体征、体质量变化、采食量变化、血清淀粉样蛋白A变化和细菌移位生长情况,并对结果进行统计学分析。结果给药后,未发现实验小鼠死亡及急性毒性体征,未观察到细菌移位生长情况,给予菌株4-2后雌性和雄性剂量组与对照组间差异没有统计学意义(F=0.697 0,P=0.567 0;F=1.289 0,P=0.312 0)。给予菌株4-2的1 d后,雌性小鼠低、中剂量组较其他组别体质量变化量小(F=4.402 0,P=0.019 0),雄性小鼠高、中、低剂量组体质量变化量小于对照组(t=-0.800 0,P=0.035 0;t=1.000 0,P=0.011 0;t=-0.800 0,P=0.035 0);给予菌株4-19的1 d后,雌性、雄性小鼠体质量变化量与对照组差异无统计学意义(F=2.024 0,P=0.151 0;F=2.507 0,P=0.096 0)。给予菌株4-2的7 d内,雌性小鼠中剂量组和低剂量组采食量大于对照组(t=0.171 4,P0.001 0;t=1.276 1,P=0.001 0),雄性小鼠剂量组与对照组采食量差异无统计学意义(F=0.327 0,P=0.806 0);给予菌株4-19的7 d内,低剂量组采食量大于对照组(t=2.137 5,P=0.036 0),雄性小鼠剂量组与对照组采食量差异无统计学意义(F=2.631 0,P=0.073 0)。结论菌株4-2、4-19在为期7 d的急性毒性动物实验中,未发现毒性表现,可用于呼吸道益生菌菌株的选择。     

病原生物学实验教学中应用多学科整合及虚拟实验的探索

病原生物学作为一门实践性很强的学科,其实验教学在其中发挥重要的作用。为了提高病原生物学实验的系统性和可操作性,结合微生态学、医学微生物学及免疫学各自学科特点,进行以"抗生素诱导的肠道菌群失调"为例探讨病原生物学整合实验。由于临床标本及实验条件的限制,采用可视化虚拟实验进行消化性溃疡中病原菌分离与鉴定及微生态菌群分析实验。这将为病原生物学实验教学的改革提供相应参考。     

Effects of decadal experimental drought and climate extremes on vegetation growth in Mediterranean forests and shrublands

Increased drought combined with extreme episodes of heatwaves is triggering severe impacts on vegetation growth, particularly for plant communities in arid and semiarid ecosystems. Although there is an abundance of short‐term field drought experiments in natural ecosystems, remaining knowledge gaps limit the understanding and prediction of vegetation growth to ongoing and future climate scenarios. Here, we assessed the impacts of long‐term (1999–2016) experimental drought (ca. ?30% rainfall) on the vegetation growth of a Mediterranean high (H) and low (L)‐canopy forests and an early‐successional shrubland, as indicated by above‐ground biomass increment (ABI) and standing density, respectively. We found habitat context (impact of historical climate change, soil depth and successional status) of the study sites significantly affected the magnitude of climate impacts; there were synergistic effects of experimental drought and meteorological drought (Standardised Precipitation–Evapotranspiration Index, SPEI) as well as extreme dry years on vegetation growth. Long‐term experimental drought decreased the ABI for the two forest canopy types and the standing density for the shrubland. Water availabilities in winter–spring (SPEIs) were positively correlated with the ABI and standing density. Moreover, experimental drought decreased the vegetation growth in extreme dry years for the shrubland. We propose that future work not only study the vegetation dynamics with physiological, phenological and demographical changes in long‐term processes and across climate gradients, but also should explore the changes of multiple functions simultaneously (e.g. multifunctionality) under long‐term processes and extremes. This type of analysis of long‐term data is essential to understand and predict biodiversity loss, composition shifts, declines in ecosystem function and carbon budgets at temporal and spatial scales, to enable policy makers to design and implement strategies for the maintenance of sustainable ecosystem function under future climate change scenarios.     

Effects of long‐term straw return on soil organic carbon storage and sequestration rate in North China upland crops: A meta‐analysis

Soil organic carbon (SOC) is essential for soil fertility and climate change mitigation, and carbon can be sequestered in soil through proper soil management, including straw return. However, results of studies of long‐term straw return on SOC are contradictory and increasing SOC stocks in upland soils is challenging. This study of North China upland agricultural fields quantified the effects of several fertilizer and straw return treatments on SOC storage changes and crop yields, considering different cropping duration periods, soil types, and cropping systems to establish the relationships of SOC sequestration rates with initial SOC stocks and annual straw C inputs. Our meta‐analysis using long‐term field experiments showed that SOC stock responses to straw return were greater than that of mineral fertilizers alone. Black soils with higher initial SOC stocks also had lower SOC stock increases than did soils with lower initial SOC stocks (fluvo‐aquic and loessial soils) following applications of nitrogen‐phosphorous‐potassium (NPK) fertilizer and NPK+S (straw). Soil C stocks under the NPK and NPK+S treatments increased in the more‐than‐20‐year duration period, while significant SOC stock increases in the NP and NP+S treatment groups were limited to the 11‐ to 20‐year period. Annual crop productivity was higher in double‐cropped wheat and maize under all fertilization treatments, including control (no fertilization), than in the single‐crop systems (wheat or maize). Also, the annual soil sequestration rates and annual straw C inputs of the treatments with straw return (NP+S and NPK+S) were significantly positively related. Moreover, initial SOC stocks and SOC sequestration rates of those treatments were highly negatively correlated. Thus, long‐term straw return integrated with mineral fertilization in upland wheat and maize croplands leads to increased crop yields and SOC stocks. However, those effects of straw return are highly dependent on fertilizer management, cropping system, soil type, duration period, and the initial SOC content.     

瑞芬太尼联合异丙酚对颅内动脉瘤夹闭术患者麻醉效果及血清S100β、NSE水平的影响

目的:探讨瑞芬太尼联合异丙酚对全麻下颅内动脉瘤夹闭术患者麻醉效果及血清中枢神经特异蛋白(S100β)、神经元特异性烯醇化酶(NSE)的影响。方法:选取2017年2月～2019年1月期间于我院行全麻下颅内动脉瘤夹闭术的患者103例,根据随机数字表法将患者分为对照组(n=51)和研究组(n=52),对照组给予异氟醚联合异丙酚麻醉,研究组给予瑞芬太尼联合异丙酚麻醉,比较两组患者麻醉效果、再出血率及血清S100β、NSE水平。结果:研究组硬脑膜切开前(T2)～动脉瘤夹闭即刻(T4)时间点心率(HR)、中心静脉压(MAP)均低于对照组(P0.05)。研究组自主呼吸恢复时间、定向力恢复时间、呼吸后睁眼时间、气管拔管时间、离开手术室时间均短于对照组(P0.05)。研究组T2～手术结束时(T5)时间点血清S100β、NSE水平低于对照组(P0.05)。两组再出血率比较差异无统计学意义(P0.05)。结论:瑞芬太尼联合异丙酚可改善全麻下颅内动脉瘤夹闭术患者的术后指标,维持血流动力学平稳,减轻脑损害。     

蝉棒束孢菌孢梗束培植过程中主要成分含量的变化规律及其复方对小鼠睡眠的影响

分析检测蝉棒束孢菌株BAI0101在培植过程中不同时间点孢梗束的转化率和孢梗束中多糖、虫草酸、腺苷和N ⁶-(2-羟乙基)腺苷含量的变化规律,对配伍的孢梗束复方辅助改善睡眠功能进行了初步评价。结果表明,从培植18d起,孢梗束的转化率呈现上升趋势,在培植30d左右,有保持稳定趋势;孢梗束中的多糖、虫草酸和腺苷含量均随着培植时间的延长呈现增高趋势,均在22-24d达到最高值,其后开始呈现降低趋势,而孢梗束中的N ⁶-(2-羟乙基)腺苷含量随着培植时间的延长呈现降低趋势,在24-26d左右达到最低值,其后呈现上升趋势,在培植至36d左右达到含量的最高值并保持稳定;对利用该菌株培植的孢梗束,经中药配伍组成的保健品小复方进行了辅助改善睡眠保健功能的初步评价,结果表明该复方有明显促进阈下剂量戊巴比妥钠诱导的小鼠睡眠作用,能明显降低巴比妥钠诱导小鼠睡眠潜伏期,且无直接睡眠作用,不影响戊巴比妥致小鼠睡眠时间,根据《保健食品检验与评价技术规范》,判定该复方具有辅助改善睡眠的保健功能。     

颅内介入栓塞术与颅内夹闭术对高分级动脉瘤性蛛网膜下腔出血患者神经功能、免疫状态及睡眠质量的影响

目的:比较颅内介入栓塞术与颅内夹闭术对高分级动脉瘤性蛛网膜下腔出血(aSAH)患者神经功能、免疫状态及睡眠质量的影响。方法:回顾性分析我院自2015年1月到2019年8月收治的高分级aSAH患者80例的临床资料,根据手术方式的不同将患者分为A组(n=38,颅内夹闭术)和B组(n=42,颅内介入栓塞术),比较两组患者疗效、神经功能、免疫状态、睡眠质量及并发症发生情况。结果:B组的预后良好率为73.81%(31/42),高于A组的60.53%(23/38)(P0.05)。两组患者术后3个月美国国立卫生研究所卒中量表(NIHSS)、匹兹堡睡眠质量指数量表(PSQI)评分均降低,且B组低于A组(P0.05)。两组患者术后1d、术后5d免疫球蛋白(Ig)G、Ig A及Ig M均呈先下降后升高趋势,B组术后1d、术后5d Ig G、Ig A及Ig M均高于A组(P0.05)。B组的术后并发症发生率为11.90%(5/42),低于A组的31.58%(12/38)(P0.05)。结论:颅内介入栓塞术应用于高分级aSAH患者的疗效优于颅内夹闭术,并且可以改善患者的神经功能、睡眠质量,减少并发症发生风险,减轻免疫抑制。     

长程运动诱发试验的两种方法在诊断低钾性周期性麻痹中的比较

摘要 目的：探究长程运动诱发试验（exercise test, ET）的两种方法在诊断低钾性周期性麻痹患者的价值比较。方法：选择2018年2月~2020年3月我院住院和门诊的72例低钾性周期性麻痹患者,根据ET检测的方法分为观察组和对照组,对比两组ET检测在运动后即刻、运动后的10、20、30、40、50、60 min的双侧尺神经进行复合肌肉动作电位（compound muscle action potential,cMAP）波幅和ET阳性率;以临床诊断结果为金指标,分析两组ET诊断价值。结果：两组的ET检测的阳性发生率对比无显著性差异（P>0.05）。两组波幅降低百分比在运动后即刻以及运动后的10、20、30、40、50、60 min对比无差异(P>0.05),在20 min后观察组波幅降低百分比趋势稍比对照组慢。临床诊断结果阳性68例,阳性率为94.44 %。观察组ET检测的特异性为50.0 %,灵敏度为88.23 %,对照组ET检测的特异性为25.0 %,灵敏度为80.88 %,观察组的特异性和灵敏度均优于对照组。结论：长程运动诱发试验是低钾型周期性麻痹诊断中重要的辅助诊断方法之一,且运动持续50 s,休息10 s,只做1个循环的方法,简单、快捷,可供临床诊断时优先选择。