高效液相色谱法测定北刘寄奴药材中木犀草素和毛蕊花糖苷的含量(英文)

建立了北刘寄奴药材中木犀草素和毛蕊花糖苷的反相高效液相含量测定方法。采用Agilent Zorbax SB-Aq C18 column (250 mm×4.6 mm, 5 μm) 色谱柱; 0.05%磷酸 (A) 和甲醇 (B) 梯度洗脱; 流速1.0 mL/min; 检测波长310 nm和350 nm。木犀草素和毛蕊花糖苷分别在0.0341-0.8172 mg/mL (r2 = 0.9999)和0.0708-2.832 mg/mL (r2 = 0.9999)范围内与峰面积呈良好的线性关系。平均加样回收率分别为102.7%和98.3%。15批北刘寄奴药材中木犀草素和毛蕊花糖苷的含量差异明显。本文首次报道了北刘寄奴药材中毛蕊花糖苷的含量测定方法。     

天蚕素A截短肽在大肠埃希菌中的高效表达及活性分析

将构建好的含抗菌肽天蚕素A(cecropin A,CA)截短肽CA19(36、210)1～5倍串连体的pET-31b(+)载体进行诱导表达,其表达量比单体表达明显提高.将融合蛋白用亲和层析法将其纯化,其纯度达到90%以上.纯化融合蛋白免疫BALB/c小鼠,制备了其特异的多克隆抗体.纯化串连融合蛋白用溴化氰切割成单体检测其活性,发现均具有抑菌活性.本研究为抗菌肽的基因工程制备提供了新途径.     

Increased nitric oxide production in hepatocytes is involved in liver dysfunction following obstructive jaundice

BACKGROUND: Obstructive jaundice damages critical functions in the liver. However, the mechanisms involved in hepatic dysfunction are obscure. Nitric oxide is implicated in liver injury under various pathological conditions. We previously reported that proinflammatory cytokine interleukin-1beta (IL-1beta) stimulated the production of nitric oxide in hepatocytes, which was associated with mitochondrial dysfunction. Studies were performed to examine whether obstructive jaundice influences the production of nitric oxide in hepatocytes and alters hepatic energy metabolism. MATERIAL AND METHODS: Hepatocytes were isolated and cultured from a rat model of obstructive jaundice or sham control. Nitric oxide production, ATP content, and ketone body ratio (acetoacetate/beta-hydroxybutyrate; KBR) were compared between the two groups in the presence of IL-1beta. RESULTS: Hepatocytes obtained from obstructive jaundice rats markedly increased the levels of nitric oxide production stimulated by IL-1beta compared with those from sham control. Western blot analysis revealed that the enhancement of nitric oxide production was a posttranslational event, since protein levels of inducible nitric oxide synthase (NOS) were unchanged between the two groups. IL-1beta decreased cellular ATP content in obstructive jaundice but not in sham control. Further, the KBR, which is a marker of mitochondrial redox state, was lower in obstructive jaundice than in sham control. Addition of N(G)-monomethyl-L-arginine, an inhibitor of NOS, abolished the decreases in ATP content and KBR as well as the nitric oxide production. CONCLUSIONS: These results indicate that a priming of nitric oxide production following obstructive jaundice is associated with the alteration of hepatic energy metabolism in part through mitochondrial dysfunction. Regulation of nitric oxide production may be a useful therapy for preventing liver dysfunction in obstructive jaundice.     

医学机能实验学教学改革与思考

广州医科大学通过以综合性实验为主体,以学生自主设计性实验、大学生课余创新性实验为支撑,以虚拟仿真实验与实体操作实验相结合的混合式教学模式为重要教学手段,同时结合基于智能模拟人系统开设的"模拟机能实验学"选修课和青少年医学科普教育活动,对机能实验学进行了改革。问卷调查显示,改革对培养学生的综合运用能力、科研素养以及临床和...     

骨髓基质细胞促进人胚神经干细胞向神经元的分化

目的:探讨骨髓基质细胞(BMSCs)对人胚神经干细胞(NSCs)分化的影响。方法:采用机械法分离人胚NSCs,成球法进行传代培养,采用免疫荧光染色检测神经上皮干细胞蛋白(Nestin)的表达鉴定NSCs。按培养方式不同,分为NSCs自然分化组、BMSCs和NSCs直接接触共培养组及Transwell共培养组,采用免疫细胞荧光法及免疫印迹法检测各组神经元和星形胶质细胞标志物的表达。结果:在直接接触共培养组和transwell共培养组中,免疫荧光染色显示神经元标志物NSE阳性细胞率明显高于自然分化组,而星形胶质细胞标志物GFAP阳性细胞率低于自然分化组。免疫印迹检测显示Transwell共培养组中NSE表达量显著高于自然分化组,而GFAP表达量低于自然分化组。结论:BMSCs具有促进NSCs向神经元分化的作用。     

Fully Bio-Based Adhesive from Tannin and Sucrose for Plywood Manufacturing with High Performances

Fully bio-based adhesives are beneficial to reduce the dependence of the wood adhesive industry on synthetic resins based on petrochemical resources and enhance the market competitiveness of adhesives. A fully bio-based wood adhesive composed of tannin and sucrose was developed and successfully used in the preparation of plywood. Effects of the preparation technology on the bonding strength and water resistance of plywood were investigated, and the properties of the adhesive were analyzed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TG) and X-ray diffraction (XRD) in this study. The results showed that: (1) Compared with other biomass adhesives, tannin–sucrose adhesive had the characteristics of high-solid content and low viscosity, which had the potential to prepare particleboard and fiberboard. (2) A proper mass ratio of tannin to sucrose was key to obtaining a tannin–sucrose adhesive with better properties. (3) The optimum preparation process of tannin–sucrose adhesive for plywood was as follows: hot-pressing temperature of 210 °C, hot-pressing time of 1.2 min/mm, m(tannin):m(sucrose) of 60:40 and adhesive loading of 160 g/m². Under these conditions, the water-resistant bonding strength of the plywood was 0.89 MPa, which met the strength requirements of the Type II standard of plywood in GB/T 17657-2013. (4) The hot-pressing temperature played a decisive role in the tannin–sucrose adhesive, and the good performance of the plywood was maintained when the temperature was 210 °C or above. Thus, the prepared tannin–sucrose adhesive had high-bonding strength, good water resistance and thermal stability.     

醒后卒中的影像学研究进展

我国最新居民致残和致死调查报告显示,卒中发病率高居首位,虽然近几年卒中致死率较前下降,但是因为疾病的致残性及后续康复带来的巨大社会支出,对卒中的探索及相关研究依然刻不容缓。急性缺血性卒中（acute ischemic stroke,AIS）占所有卒中的85%,醒后卒中（wake-up stroke,WUS）又占其中的20%左右。因在睡眠中发病,故具体发病时间不详。事实上,很多患者疾病发生在醒来前的很短时间,但治疗上却错失了溶栓或血管内治疗的机会,最终导致预后不良。目前针对WUS发病时间的研究越来越多,其中通过影像学手段推测WUS的发病时间指导其治疗尤为热门。本文对WUS的近期影像学研究进展作一综述。     

GBZ 97-2017 《职业性放射性肿瘤判断规范》解析——放射性肿瘤病因概率方法的不确定性

放射性肿瘤病因概率（PC）方法具有先天的不确定性,这是我国国家标准中亟待加强的部分。笔者总结了放射性肿瘤PC方法不确定性的来源和主要内容,以及不确定性的分析和评估的研究现状,并介绍了降低PC方法不确定度的几种措施。     

Clinical significance of procalcitonin in critically ill patients with pneumonia receiving bronchoalveolar lavage

Background:As a useful tool in intensive care units (ICU), fiberoptic bronchoscopy (FOB) may cause a deterioration of infection. This study is to investigate the clinical significance of procalcitonin (PCT) in critically ill patients with severe pneumonia receiving bronchoalveolar lavage (BAL).Methods:A retrospective case-control study was performed in a single respiratory ICU (RICU) with 6-bed. Critically ill patients with severe pneumonia admitted to RICU were consecutively reviewed from March 2017 to October 2019. Chi-square test, Wilcoxon test, Mann Whitney U-test, Kaplan–Meier survival analysis or Cox’s proportional hazards regression model was used as appropriate.Results:A total of 72 eligible patients were included in the final analysis, 51 of which received BAL performed by FOB. Serum levels of PCT in group received BAL is markedly increased at 24 hours after FOB (p<0.001). Forty-eight hours later, BAL group with decreased serum levels of PCT had less SOFA score and decreased mortality compared with those with increased serum levels of PCT. Furthermore, Kaplan-Meier analysis indicated that patients with decreased serum levels of PCT had improved survival rate during hospital (Breslow test, p=0.041). However, increased PCT after BAL was not an independent risk factor for in-hospital mortality (hazard ratio: 1.689, 95% CI(0.626 ,4.563), p=0.301).Conclusions:BAL performed by FOB increased serum levels of PCT. However, PCT levels decreased at 48 hours after BAL predicted a good prognosis of patients with severe pneumonia.     

Molecular mechanisms of alveolar epithelial cell senescence and idiopathic pulmonary fibrosis: a narrative review

Background and ObjectiveIdiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial pneumonia of unknown etiology. An increasing number of studies have reported that the incidence of IPF increases with age. Simultaneously, the number of senescent cells increased in IPF. Epithelial cell senescence, an important component of epithelial cell dysfunction, plays a key role in IPF pathogenesis. This article summarizes the molecular mechanisms associated with alveolar epithelial cell senescence and recent advances in the applications of drugs targeting pulmonary epithelial cell senescence to explore novel therapeutic approaches for the treatment of pulmonary fibrosis.MethodsAll literature published in English on PubMed, Web of Science, and Google Scholar were electronically searched online using the following keyword combinations: aging, alveolar epithelial cell, cell senescence, idiopathic pulmonary fibrosis, WNT/β-catenin, phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), mammalian target of rapamycin (mTOR), and nuclear factor kappa B (NF-κB).Key Content and FindingsWe focused on signaling pathways associated with alveolar epithelial cell senescence in IPF, including WNT/β-catenin, PI3K/Akt, NF-κB, and mTOR signaling pathways. Some of these signaling pathways are involved in alveolar epithelial cell senescence by affecting cell cycle arrest and secretion of senescence-associated secretory phenotype-associated markers. We also found that changes in lipid metabolism in alveolar epithelial cells can be induced by mitochondrial dysfunction, both of which contribute to cellular senescence and development of IPF.ConclusionsDecreasing senescent alveolar epithelial cells may be a promising strategy for the treatment of IPF. Therefore, further investigations into new treatments of IPF by applying inhibitors of relevant signaling pathways, as well as senolytic drugs, are warranted.