Effect of tight junction protein of intestinal epithelium and permeability of colonic mucosa in pathogenesis of injured colonic barrier during chronic recovery stage of rats with inflammatory bowel disease

Objective: To discuss the changes in the tight junction protein of intestinal epithelium and permeability of colonic mucosa and its possible mechanism by building the rat mode of inflammatory bowel disease at the chronic recovery stage. Methods: A total of 36 SD rats were divided into the model group and control one according to the random number table, with 18 rats in each group. Rats in the model group were given the 3% dextran sulfate sodium solution by the way of drinking for 7 d to build the rat model of inflammatory bowel disease, while rats in the control group were given free drinking of water. Six rats were executed at day 7, 14 and 21 respectively. The colonic tissues were collected from rats to observe the pathological changes of colonic mucosa. The activity of myeloperoxidase was detected and the white blood count was performed for rats in each group. The Ussing chamber technique was employed to detect the transepithelial electrical resistance(TER) and short-circuit current(SC) of colonic mucosa of rats in different time intervals; the quantum dots labeling technique was employed to detect the expression level of claudin-1 and claudin-2 in the colonic tissues. Results: After the successful modeling, the weight of rats in the model group was significantly reduced, while the disease activity index score was increased. The weight was at the lowest level at day 14 and then it began to increase afterwards. The disease activity index score was at the highest level at day 12 and then it began to decrease gradually. The activity of myeloperoxidase and WBC for rats in the model group all reached the peak value at day 14 and then decreased gradually. There was no significant difference in the changes of TER and SC in different time intervals for rats in the control group(P>0.05). TER of model group was at the lowest level at day 14 and then increased gradually; SC was at the highest level at day 14 and then decreased gradually. TER of model group at day 7, 14 and 21 was significantly lower than that of control group, while SC of model group was significantly higher than that of control group(P<0.05). There was no significant difference in the change of mean fluorescence intensity of claudin-1 and claudin-2 in different time intervals for rats in the control group(P>0.05). The claudin-1 and claudin-2 for rats in the model group reached the highest level at day 14 and then decreased gradually. The claudin-1 and claudin-2 of model group at day 7, 14 and 21 was significantly higher than that of control group(P<0.05). Conclusions: After the acute stage, the inflammatory bowel disease is then in the chronic recovery stage; the increased permeability of colonic mucosa and increased expression of tight junction protein of intestinal epithelium are closely related to the pathogenesis and development of disease. The tight junction protein plays a key role in the pathogenesis of injured colonic barrier of inflammatory bowel disease.

Detrimental Effect of Electromagnetic Pulse Exposure on Permeability of In Vitro Blood-brain-barrier Model

Objective To study the effect of electromagnetic pulse (EMP) exposure on permeability of in vitro blood-brain-barrier (BBB) model. Methods An in vitro BBB model, established by co-culturing brain microvascular endothelial cells (BMVEC) and astroglial cells (AC) isolated from rat brain, was exposed to EMP at 100 kV/m and 400 kV/m, respectively. Permeability of the model was assayed by measuring the transendothelial electrical resistance (TEER) and the horseradish peroxidase (HRP) transmission at different time points. Levels of BBB tight junction-related proteins were measured at 0, 1, 2, 4, 8, 12, 16, 20, 24 h after EMP exposure by Western blotting. Results The TEER level was lower in BBB model group than in control group at 12 h after EMP, exposure which returned to its normal level at 24 h. The 24 h recovery process was triphasic and biphasic respectively after EMP exposure at 100 kV/m and 400 kV/m. Following exposure to 400 kV/m EMP, the HRP permeability increased at 1-12 h and returned to its normal level at 24 h. Western blotting showed that the claudin-5 and ZO-1 protein levels were changed after EMP exposure. Conclusion EMP exposure at 100 kV/m and 400 kV/m can increase the permeability of in vitro BBB model and BBB tight junction-related proteins such as ZO-1 and claudin-5 may change EMP-induced BBB permeability.

Critical parameters of horizontal well influenced by semi-permeable barrier in bottom water reservoir

It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on previous research on impermeable reservoir barrier, a mathematical flow model was derived for a horizontal well of a bottom water drive reservoir with a semi-permeable barrier. Besides, analytical equations were also presented to calculate critical parameters, such as production rate,pressure and potential difference. The effects of barrier, well and reservoir parameters on our model results were further investigated.The results show that the larger the barrier size is or the higher the barrier location is, the higher the critical production rate and potential difference of a horizontal well are. When the barrier permeability equals the formation permeability or the barrier width equals zero, the critical production rates converge to the values same to that of the case with no barrier. When the barrier permeability equals zero, the problem is regarded as a case of impermeable barrier. This model can be applied to predicting horizontal wells' critical production parameters in reservoirs with semi-permeable barriers.

Correlation of vascular endothelial growth factor to permeability of blood-brain barrier and brain edema during high-altitude exposure

BACKGROUND:Many studies have evaluated the role of vascular endothelial growth factor(VEGF) in traumatic brain edema and hemorrhagic brain edema. OBJECTIVE:To observe the effects of VEGF expression on permeability of the blood-brain barrier (BBB) during high-altitude and hypoxia exposure,and to investigate the correlation between VEGF expression and BBB permeability with regard to Evans blue staining and brain edema during high-altitude exposure. DESIGN,TIME AND SETTING:The randomized,controlled,animal study was performed at the Tanggula Etape,Central Laboratory of Chengdu Medical College,and Central Laboratory of General Hospital of Chengdu Military Area Command of Chinese PLA,China,from July 2003 to November 2004. MATERIALS:Quantitative RT-PCR kit(Sigma,USA),VEGF ELISA kit(Biosource,USA),and Evans blue(Jingchun,China) were acquired for this study. METHODS:A total of 180 Wistar rats were equally and randomly assigned to 15 groups:low-altitude (500 m),middle-altitude(2 880 m),high-altitude(4 200 m),super-high-altitude(5 000 m),1,3,5,7,9, 11,13,15,17,19,and 21 days of super high-altitude exposure.Wistar rats were exposed to various altitude gradients to establish a hypoxia model. MAIN OUTCOME MEASURES:Brain water content was calculated according to the wet-to-dry weight ratio.BBB permeability to Evans blue was determined by colorimetric method.VEGF mRNA and protein levels in brain tissues were detected using RT-PCR and double-antibody sandwich ELISA. RESULTS:Brain water content,BBB permeability to Evans blue,and VEGF mRNA and protein levels in brain tissues increased with increasing altitude and prolonged exposure to altitude.The greatest increase was determined on day 9 upon ascending 5 000 m.Simultaneously,VEGF expression positively correlated to BBB permeability of Evans blue and brain water content(r = 0.975,0.917,P<0.01). CONCLUSION:Increased VEGF protein and mRNA expression was responsible for increased BBB permeability,which may be an important mechanism underlying brain edema during high-altitude exposure.

Effect of Electromagnetic Pulse Exposure on Permeability of Blood-testicle Barrier in Mice

Objective To study the effect of electromagnetic pulse (EMP) exposure on the permeability of blood-testicle barrier (BTB) in mice. Methods Adult male BALB/c mice were exposed to EMP at 200 kV/m for 200 pulses with 2 seconds interval. The mice were injected with 2% Evans Blue solution through caudal vein at different time points after exposure, and the permeability of BTB was monitored using a fluorescence microscope. The testis sample for the transmission electron microscopy was prepared at 2 h after EMP exposure. The permeability of BTB in mice was observed by using Evans Blue tracer and lanthanum nitrate tracer. Results After exposure, cloudy Evans Blue was found in the testicle convoluted seminiferous tubule of mice. Lanthanum nitrate was observed not only between testicle spermatogonia near seminiferous tubule wall and sertoli cells, but also between sertoli cells and primary spermatocyte or secondary spermatocyte. In contrast, lanthanum nitrate in control group was only found in the testicle sertoli cells between seminiferous tubule and near seminiferous tubule wall. Conclusion EMP exposure could increase the permeability of BTB in the mice.

Changes in the permeability of blood brain barrier and endothelial cell damage after cerebral ischemia

OBJECTIVE: To investigate the effect of endothelial cells on the permeability of blood brain barrier (BBB) after brain injury and its effect mechanism. DATA SOURCES: We searched for the articles of permeability of BBB and endothelial cell injury after brain ischemia, which were published between January 1982 and December 2005, with the key words of “cerebral ischemia damage,blood brain barrier ( BBB),permeability,effect of endothelial cell (EC) and its variation mechanism”in English. STUDY SELECTION: The materials were primarily selected. The articles related to the changes in the permeability of BBB and the effect of endothelial cells as well as the change mechanism after cerebral ischemia damage were chosen. Repetitive studies or review articles were excluded. DATA EXTRACTION: Totally 55 related articles were collected, and 35 were excluded due to repetitive or review articles, finally 20 articles were involved. DATA SYNTHESIS: The content or viewpoints of involved literatures were analyzed. Cerebral ischemia had damage for endothelial cells, such as the inflow of a lot of Ca2+, the production of nitrogen monoxide and oxygen free radical, and aggravated destruction of BBB. After acceptors of inflammatory mediators on cerebrovascular endothelial cell membrane, such as histamine, bradykinin , 5-hydroxytryptamine and so on are activated, endothelial cells shrink and the permeability of BBB increases. Its mechanism involves in the inflow of extracellular Ca2+and the release of intracellular Ca2+ in the cells. Glycocalyx molecule on the surface of endothelial cell, having structural polytropy, is the determinative factor of the permeability of BBB. VEGF, intensively increasing the vasopermeability and mainly effecting on postcapillary vein and veinlet, is the strongest known blood vessel permeation reagent. Its chronic overexpression in the brain can lead the destruction of BBB. CONCLUSION: The injury of endothelial cell participants in the pathological mechanism of BBB destruction after cerebral ischemia.

Comparative Toxicity of Nanomaterials to Air-blood Barrier Permeability Using an In Vitro Model

Objective To comparatively study the toxicity of four metal-containing nanoparticles(MNPs) and their chemical counterparts to the air-blood barrier(ABB) permeability using an in vitro model.Methods ABB model, which was developed via the co-culturing of A549 and pulmonary capillary endothelium, was exposed to spherical CuO-NPs(divided into CuO-40, CuO-80, and CuO-100 based on particle size), nano-Al2O3(sheet and short-rod-shaped), nano-ZnO, nano-Pb S, CuSO4, Al2(SO4)3, Zn(CH3COO)2, and Pb(NO3)2 for 60 min.Every 10 min following exposure, the cumulative cleared volume(ΔTCL) of Lucifer yellow by the model was calculated.A clearance curve was established using linear regression analysis of ΔTCL versus time.Permeability coefficient(P) was calculated based on the slope of the curve to represent the degree of change in the ABB permeability.Results The results found the increased P values of CuO-40, CuO-80, sheet, and short-rod-shaped nano-Al2O3, Al2(SO4)3, and Pb(NO3)2.Among them, small CuO-40 and CuO-80 were stronger than CuO-100 and CuSO4;no difference was observed between Al2(SO4)3 and sheet and short-rod-shaped nano-Al2O3;and nano-Pb S was slightly weaker than Pb(NO3)2.So clearly the MNPs possess diverse toxicity.Conclusion ABB permeability abnormality means pulmonary toxicity potential.More studies are warranted to understand MNPs toxicity and ultimately control the health hazards.

Relationship of gelatinases-tight junction proteins and blood-brain barrier permeability in the early stage of cerebral ischemia and reperfusion

Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This study established a rat model of 1.5-hour middle cerebral artery occlusion with reperfusion. Protein expression levels of claudin-5 and occludin gradually decreased in the early stage of reperfusion, which corresponded to the increase of the gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. In addition, rats that received treatment with matrix metalloproteinase inhibitor N-[(2R)-2-(hydroxamidocarbonylmethyl)-4-methylpenthanoyl]-L- tryptophan methylamide (GM6001) showed a significant reduction in Evans blue leakage and an inhibition of claudin-5 and occludin protein degradation in striatal tissue. These data indicate that matrix metalloproteinase-2 and matrix metalloproteinase-9-mediated claudin-5 and occludin degradation is an important reason for blood-brain barrier leakage in the early stage of reperfusion. The leakage of the blood-brain barrier was present due to gelatinases-mediated degradation of claudin-5 and occludin proteins. We hypothesized that the timely closure of the structural component of the blood-brain barrier (tight junction proteins) is of importance.

Performance of Metal and Acid Ions Remediation in Contaminated Soils by Electrokinetics with Chitosan Permeable Reactive Barrier

Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.

Pilot Test of the Permeable Reactive Barrier for Removing Uranium from the Flooded Gunnar Pit

This work reports on applying iron oxide coated sand (IOCS) media in an experimental permeable reactive barrier to remove uranium (U) species from uranium containing water. A field study was conducted at the legacy Gunnar uranium mine & mill site that was abandoned in the 1960s with limited to no decommissioning. The flooded Gunnar mine pit presently contains about 3.2 million m3 of water contaminated by dissolved U (1.2 mg/L), Ra-226 (0.4 Bq/L), and minor concentrations of other contaminants (As, Se, etc.). The water is seeping over the pit rim into Lake Athabasca, posing potential environmental and health concerns. IOCS media can be used to immobilize uranium species through an adsorption process. Herein, the preparation of hydrous ferric oxide sorbents and their supported forms onto silica sands is described. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (pXRD) were used for structural characterization. The adsorption properties of the IOCS sorbent media were modeled by the Langmuir adsorption isotherm, where a maximum uranium uptake capacity was estimated. Bench-scale adsorption kinetic experiments were also performed before moving to a field trial. Based on these lab results and input on field-scale parameters, a pilot permeable reactive barrier was fabricated and a field test conducted near the Gunnar pit in June 2019. This pilot test provided technical data and information needed for designing a full-scale permeable barrier that employs the IOCS media. This approach can be applied for in-situ water treatment at Gunnar and other legacy uranium sites.

Protocadherin gamma C3:a new player in regulating vascular barrier function

Defects in the endothelial cell barrier accompany diverse malfunctions of the central nervous system such as neurodegenerative diseases,stroke,traumatic brain injury,and systemic diseases such as sepsis,viral and bacterial infections,and cancer.Compromised endothelial sealing leads to leaking blood vessels,followed by vasogenic edema.Brain edema as the most common complication caused by stroke and traumatic brain injury is the leading cause of death.Brain microvascular endothelial cells,together with astrocytes,pericytes,microglia,and neurons form a selective barrier,the so-called blood-brain barrier,which regulates the movement of molecules inside and outside of the brain.Mechanisms that regulate blood-brain barrier permeability in health and disease are complex and not fully understood.Several newly discovered molecules that are involved in the regulation of cellular processes in brain microvascular endothelial cells have been described in the literature in recent years.One of these molecules that are highly expressed in brain microvascular endothelial cells is protocadherin gamma C3.In this review,we discuss recent evidence that protocadherin gamma C3 is a newly identified key player involved in the regulation of vascular barrier function.

血-迷路屏障通透性与突聋发病机制及预后的关系:在3D real IR的发现

目的分析突聋患者的内耳钆造影MRI三维真实重建反转恢复(three dimensional real inversion recovery,3D real IR)成像上的表现,探讨血-迷路屏障的通透性与突聋发病机制及其预后的关系。方法对41例单侧突聋患者行内耳钆造影MRI,测量患耳和健耳的耳蜗信号强度,并测量延髓信号强度,分别计算出耳蜗/延髓比值(cochlear/medulla ratio,CM ratio),以CM比值作为血-迷路屏障通透性的标志物,分析突聋患者患耳、健耳CM比值的不对称程度与疗效之间的关系。结果41例患者中,33例(80.48%)患耳的CM比值高于健耳,差异有统计学意义(P<0.05);患耳CM比值为健耳的1.5倍以下者18例,治疗有效率为77.78%(14/18);患侧CM比值不高于健侧者8例,治疗有效率为100%;达到健耳的1.5倍至1.75倍之间者7例,治疗有效率为100%(7/7);达到健耳的1.75倍至2.0倍之间者2例,治疗有效率为50%(1/2);达到健耳的2.0倍以上者14例,治疗有效率为14.28%(12/14);差异有统计学意义(P<0.05)。结论内耳3D Real IR可显示突聋患者血-迷路屏障通透性的改变,80.48%的突聋患者患侧耳蜗出现高信号,患耳CM比值达健耳的1.75倍以上者多数预后不良。

不同强度累积和持续运动对胰岛素抵抗小鼠肠黏膜通透性的影响

背景:胰岛素抵抗与小肠黏膜通透性的关系可能与脂肪过多、炎症和氧化应激等有关。目前不同种类的运动对该关系的影响尚不清楚,还需要进一步进行相关机制研究。目的:以高脂饲料诱导胰岛素抵抗小鼠模型,观察不同形式的长期运动(持续运动和累积运动)对胰岛素抵抗小鼠肠黏膜通透性的影响,并比较不同运动强度的效果差异,以评价累积运动的健康促进效应。方法:采用4周龄雄性C57BL/6J小鼠,以高脂饲料诱导胰岛素抵抗小鼠模型,造模成功的小鼠随机分为5组,分别为高脂胰岛素抵抗组、普食胰岛素抵抗组、中强度持续运动组、中强度累积运动组、高强度累积运动组,其中高脂胰岛素抵抗组饲以高脂饲料,其余各组饲以普通饲料。各运动组接受8周的不同形式的跑台训练:中强度持续运动组小鼠进行50 min,速度为11 m/min的运动;中强度累积运动组小鼠进行每天4次,每次12.5 min(次与次间隔3 h),速度为11 m/min的运动;高强度累积运动组小鼠进行每天4次、每次7.5 min(次与次间隔3 h),速度为19 m/min的运动。末次运动48 h后取材,检测各组小鼠血清中的脂多糖和右旋乳酸含量,采用苏木精-伊红染色观察回肠组织病理变化,通过Western blot法检测肠道紧密连接蛋白的表达,ELISA法测定血液和回肠组织中的炎症因子白细胞介素10、肿瘤坏死因子α及肠道黏膜分泌性免疫球蛋白A的表达。结果与结论:①高脂膳食诱导的胰岛素抵抗小鼠伴有体质量增加、血清内毒素和右旋乳酸水平显著升高、血清和小肠组织促炎因子肿瘤坏死因子α水平显著增加等表现;长期规律性的累积运动和持续运动均可降低胰岛素抵抗小鼠的体质量,并明显改善糖代谢功能,纠正或改善胰岛素抵抗症状;②长期规律性的累积运动和持续运动均可提高肠黏膜组织中紧密连接蛋白的表达量并增加分泌性免疫球蛋白A分泌量,从而改善肠黏膜通透性,增强肠道免疫功能,降低血清中内毒素脂多糖的含量,进而降低循环血和肠组织中的促炎症因子表达,最终发挥对胰岛素抵抗小鼠肠黏膜屏障的保护作用;③等运动量的高强度累积运动与中强度累积运动、中强度持续运动相比,在降低胰岛素抵抗小鼠的体质量、改善胰岛素抵抗症状、保护肠黏膜屏障方面效果更明显。

厚朴三物汤调节脓毒症急性胃肠功能障碍的疗效观察

目的探讨厚朴三物汤调节脓毒症急性胃肠功能障碍的疗效及对肠道微生态的影响。方法选择2022年2月至2023年2月脓毒症并发急性胃肠功能障碍患者60例。采用随机数表法分为2组。对照组予常规西医治疗,观察组在常规治疗基础上加用厚朴三物汤治疗。留取患者入ICU治疗7 d后的粪便标本进行高通量16S rRNA基因测序分析。对比患者治疗前、治疗7 d后的炎症因子、肠道通透性因子及免疫屏障功能指标水平。结果观察组患者粪便中,厚壁菌门中兼性厌氧菌属的相对丰度较高,包括颗粒链球菌、孪生球菌属、肉杆菌科属及嗜血菌属等;对照组患者粪便中以厌氧厚壁菌门菌属为主,包括梭菌属、月形单胞菌属、韦荣球菌属及厌氧棍状菌属,其肠道菌群的丰富度和多样性明显低于观察组。治疗7 d后,两组患者血清TNF-α、hs-CRP、WBC、IL-6指标水平均降低,且观察组血清TNF-α、hs-CRP、WBC、IL-6指标比对照组低(P<0.05);两组患者肠道通透性因子DAO、D-乳酸指标水平低于治疗前,观察组DAO、D-乳酸指标比对照组低(P<0.05);两组患者肠道免疫屏障功能IgA、IgM、IgG指标较治疗前升高,观察组IgA、IgM、IgG指标高于对照组(P<0.05)。结论厚朴三物汤可以有效改善脓毒症急性胃肠功能障碍患者的肠道微生态,降低炎症反应,进而提高肠道免疫屏障功能,有利改善患者预后康复质量。

植物乳植杆菌CCFM8661对小鼠肠道菌群及肠道屏障的影响

为探讨植物乳植杆菌CCFM8661对小鼠肠道菌群的影响,将小鼠适应性培养一周后,分别用低(1.6×106 CFU/只)、中(1.6×107CFU/只)、高(1.6×108CFU/只)剂量的植物乳植杆菌CCFM8661灌胃,干预14 d。分别检测干预前后小鼠粪便中双歧杆菌、乳杆菌、肠球菌、肠杆菌、产气荚膜梭菌的变化情况,并测定组织病理、肠道屏障、肠道通透性、短链脂肪酸相关指标,评价植物乳植杆菌CCFM8661对肠道微生物及肠道屏障的调节作用。结果表明,植物乳植杆菌CCFM8661可增加小鼠肠道双歧杆菌及乳杆菌含量并抑制产气荚膜梭菌的增殖;同时,喂食植物乳植杆菌CCFM8661可明显改变小鼠的肠道通透性、降低肠道中脂多糖(lipopolysaccharide,LPS)和D⁃乳酸的含量、增强肠道屏障、提高肠道中短链脂肪酸(乙酸、丙酸和丁酸)的含量。综上,植物乳植杆菌CCFM8661能够调节肠道菌群,对肠道屏障具有一定的保护作用。

细胞紧密连接与鸡肠道疾病的互作关系

紧密连接是肠道上皮屏障的重要结构基础,负责连接相邻肠道上皮细胞,建立物理屏障,调控物质经细胞旁路转运和维持细胞表面极性。紧密连接主要由咬合蛋白、闭合蛋白、连接黏附分子、闭锁小带蛋白和细胞骨架丝状肌动蛋白等成分组装而成,其表达异常和功能紊乱与细菌、病毒、寄生虫或霉菌毒素等因素引起的鸡肠道疾病密切相关。文章就紧密连接相关蛋白的结构、功能及与鸡肠道疾病发生发展的互作关系进行综述,旨在为降低和修复病原微生物及霉菌毒素所引起的肠道屏障损伤提供理论依据。

可渗透反应墙除砷的研究进展与展望

砷类化合物造成的环境污染严重影响生态和人类健康,有效地去除和防治砷污染是当前工业发展中亟待解决的问题之一.基于原位修复的可渗透反应墙(PRB)技术具有低成本、高效能、可持续性和工艺简单等优点,利用PRB技术防治砷污染是一种绿色、经济又高效的选择.PRB中的填充材料是除砷的反应主体,因此总结了PRB除砷填充材料及其除砷性能与机理,包括黏土矿物、碳基材料、钙基材料、铁基材料和固体废弃物等.其中,铁基材料对砷物种的固定能力较其它材料更为突出,零价铁、铁矿物、废铁材料等铁基材料广泛应用于砷污染修复,廉价易得又高效的铁基材料是未来PRB除砷材料的重要研究方向.在此基础上,简要介绍了除砷PRB填充材料的实验研究与模拟,并通过PRB除砷工程或中试实验阐述了PRB的运行监测与砷污染治理效果,展望了PRB除砷材料和工程应用的发展前景与挑战,以促进我国地表径流砷污染治理PRB材料和技术的开发与进步.

内耳钆增强磁共振3D CUBE FLAIR序列PPI及HYDROPS图像在诊断内淋巴积水中的价值

目的 探讨经静脉注射钆对比剂行内耳增强磁共振三维快速液体衰减反转恢复序列(three-dimensional fluid attenuated inversion recovery with CUBE,3D CUBE FLAIR)阳性内淋巴影像(positive perilymph image,PPI)及HYDROPS (HYbriD of reversed image of positive endolymph signal and native image of positive perilymph signal)图像在内淋巴积水(endolymphatic hydrops,EH)中的诊断价值。材料与方法 回顾性分析患侧EH、对侧无EH患者资料及MRI图像22例。应用Image J软件在所获图像上勾画感兴趣区,测量同一图像上患侧及健侧的耳蜗底周与同侧小脑白质区信号强度比(signal intensity ratio,SIR)、同一侧前庭外淋巴与内淋巴间隙SIR;对PPI及HYDROPS图像上患侧耳蜗积水数量及前庭积水边界清晰程度评分。评估两种图像对患侧血-迷路屏障(blood-labyrinth barrier,BLB)通透性改变的显示情况、同侧前庭在两种图像上的成像效果、评估两种图像对耳蜗EH敏感性及前庭EH边界的显示情况。结果 PPI图像中患侧及健侧的耳蜗底周与同侧小脑白质区SIR之间的差异具有统计学意义(P<0.001);HYDROPS图像中患侧及健侧耳蜗底周与同侧小脑白质区SIR之间的差异具有统计学意义(P<0.001)。PPI图像及HYDROPS图像上的患侧前庭外淋巴与内淋巴间隙SIR之间的差异具有统计学意义(P<0.001);PPI图像及HYDROPS图像上的健侧前庭外淋巴与内淋巴SIR间隙之间的差异具有统计学意义(P<0.001)。PPI图像及HYDROPS图像诊断耳蜗EH的敏感性之间的差异具有统计学意义(P=0.030)。PPI图像及HYDROPS图像患侧前庭内淋巴间隙边界清晰程度评分之间的差异具有统计学意义(P<0.001)。结论 内耳钆增强磁共振3D CUBE FLAIR序列PPI及HYDROPS图像综合应用,有利于评估患侧BLB通透性、积水部位以及前庭EH边界的显示。