The nature of brain interstitial fluid （ISF） has long been a subject of controversy. Most of the previous studies on brain ISF were carded out in vitro. In the present study, a novel method was developed to characte...The nature of brain interstitial fluid （ISF） has long been a subject of controversy. Most of the previous studies on brain ISF were carded out in vitro. In the present study, a novel method was developed to characterize ISF in the living rat brain by magnetic resonance （MR） imaging using gadolinium-diethylenetriaminepentaacetic acid （Gd-DTPA） as a tracer. Sprague Dawley rats （n=8） were subjected to MR scanning before and after the introduction of Gd-DTPA into the caudate nucleus. A one-way drainage of brain ISF was demonstrated on the dynamic MR images. According to the traditional diffusion model, the diffusion and clearance rate constants of the tracer within brain extracellular space （ECS） were derived as （3.38±1.07）×10^-4 mm2 s^-1 and （7.60±4.18）×10^-5 s^-1. Both diffusion and bulk flow contributed to the drainage of ISF from the caudate nucleus, which demonstrated an ISF-cerebrospinal fluid confluence in the subarachnoid space at the lateral and ventral surface of the brain cortex at 3 h after the injection. By using this newly developed method, the brain ECS and ISF can be quantitatively measured simultaneously in the living brain, which will enhance the understanding of ISF and improve the efficiency of drug therapy via the brain interstitium.展开更多
为探究正常牛肉与DFD(dark,firm and dry)牛肉成熟过程中水分状态变化及其对保水性的影响,本实验以正常牛肉和DFD牛肉的背最长肌(M.longissimus lumborum)作为研究对象,使用低场核磁共振技术探究DFD牛肉与正常牛肉分别在成熟3、7、14 d...为探究正常牛肉与DFD(dark,firm and dry)牛肉成熟过程中水分状态变化及其对保水性的影响,本实验以正常牛肉和DFD牛肉的背最长肌(M.longissimus lumborum)作为研究对象,使用低场核磁共振技术探究DFD牛肉与正常牛肉分别在成熟3、7、14 d和21 d时水分状态的变化,并通过肌节长度和细胞外空间比组织学指标分析成熟过程中DFD牛肉与正常牛肉保水性差异的原因。结果表明:成熟过程中正常牛肉和DFD牛肉保水性均呈下降趋势,其中DFD牛肉保水性显著高于正常牛肉(P<0.05),DFD牛肉中结合水、不易流动水和自由水的自由度较低,且结合水相对含量较高;DFD牛肉肌节长度显著低于正常牛肉(P<0.05),肌节内狭窄的储水空间可降低肉中水分的自由度,并且成熟过程中DFD牛肉肌细胞始终保持完整形态,细胞水分散失减少,因此DFD牛肉能够在成熟过程中保持良好的保水性。本研究结果阐述了DFD和正常牛肉成熟过程中的水分状态变化,并从不同水分状态和肌肉组织学角度揭示了DFD牛肉成熟过程中保水性较好的原因,可为提高牛肉保水性提供理论指导。展开更多
The respiratory burst of neutrophils is an important response in inflammation. The alterations in extracellular pH per se is not a sufficient trigger to the respiratory burst in neutrophils. While neutrophils in respo...The respiratory burst of neutrophils is an important response in inflammation. The alterations in extracellular pH per se is not a sufficient trigger to the respiratory burst in neutrophils. While neutrophils in respose to conventional agonists, the respiratory burst in neutrophils is affected by the alterations in extracellular pH, and there is a direct relationship between intracellular and extracellular pH. O-· 2 production in neutrophils is decreased while H 2O 2 production is increased at acidic pH. O-· 2 release in neutrophils is enhanced at weak alkaline pH. Na+/H+ exchanger plays an important role in the regulation of the respiratory burst of neutrophils.展开更多
The smooth transportation of substances through the brain extracellular space(ECS)is crucial to maintaining brain function;however,the way this occurs under simulated microgravity remains unclear.In this study,tracer-...The smooth transportation of substances through the brain extracellular space(ECS)is crucial to maintaining brain function;however,the way this occurs under simulated microgravity remains unclear.In this study,tracer-based magnetic resonance imaging(MRI)and DECS-mapping techniques were used to image the drainage of brain interstitial fluid(ISF)from the ECS of the hippocampus in a tail-suspended hindlimb-unloading rat model at day 3(HU-3)and 7(HU-7).The results indicated that drainage of the ISF was accelerated in the HU-3 group but slowed markedly in the HU-7 group.The tortuosity of the ECS decreased in the HU-3 group but increased in the HU-7 group,while the volume fraction of the ECS increased in both groups.The diffusion rate within the ECS increased in the HU-3 group and decreased in the HU-7 group.The alterations to ISF drainage and diffusion in the ECS were recoverable in the HU-3 group,but neither parameter was restored in the HU-7 group.Our findings suggest that early changes to the hippocampal ECS and ISF drainage under simulated microgravity can be detected by tracer-based MRI,providing a new perspective for studying microgravity-induced nano-scale structure abnormities and developing neuroprotective approaches involving the brain ECS.展开更多
目的探讨镍冶炼烟尘对中国仓鼠肺细胞(CHL)毒性和细胞间隙连接通讯(GJIC)的影响。方法以CHL细胞为靶细胞,采用噻唑蓝(MTT)颜色反应法,检测2份镍冶炼烟尘对CHL细胞的毒性作用。采用划痕标记染料示踪技术(scrape-loading and dye transfer...目的探讨镍冶炼烟尘对中国仓鼠肺细胞(CHL)毒性和细胞间隙连接通讯(GJIC)的影响。方法以CHL细胞为靶细胞,采用噻唑蓝(MTT)颜色反应法,检测2份镍冶炼烟尘对CHL细胞的毒性作用。采用划痕标记染料示踪技术(scrape-loading and dye transfer,SLDT)检测镍冶炼烟尘对CHL细胞GJIC的影响。结果2份受试物各剂量组在作用6、12 h时,CHL细胞增殖情况与对照组比较,差异无统计学意义(P>0.05)。作用36 h时,所有剂量组细胞存活率均降低,与对照组比较,差异有统计学意义(P<0.05),并呈现剂量-反应和时间-反应的关系。2份受试物作用CHL细胞36 h时IC50分别为21.36、23.07μg/ml。镍冶炼烟尘在25.00、50.00、100.00μg/ml时,荧光黄(LY)由伤沿列传向邻近细胞的列数减少,与溶剂对照组比较,差异有统计学意义(P<0.01),细胞间隙连接通讯能力降低。结论镍冶炼烟尘对体外培养的CHL细胞可产生毒性作用,抑制细胞生长。一定浓度的镍冶炼烟尘能够抑制CHL细胞的GJIC。展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 30972811, 81171080 and 81071148)the Twelfth Five-year Plan for National Science and Technology of China (Grant No.2012BAI15B009)
文摘The nature of brain interstitial fluid （ISF） has long been a subject of controversy. Most of the previous studies on brain ISF were carded out in vitro. In the present study, a novel method was developed to characterize ISF in the living rat brain by magnetic resonance （MR） imaging using gadolinium-diethylenetriaminepentaacetic acid （Gd-DTPA） as a tracer. Sprague Dawley rats （n=8） were subjected to MR scanning before and after the introduction of Gd-DTPA into the caudate nucleus. A one-way drainage of brain ISF was demonstrated on the dynamic MR images. According to the traditional diffusion model, the diffusion and clearance rate constants of the tracer within brain extracellular space （ECS） were derived as （3.38±1.07）×10^-4 mm2 s^-1 and （7.60±4.18）×10^-5 s^-1. Both diffusion and bulk flow contributed to the drainage of ISF from the caudate nucleus, which demonstrated an ISF-cerebrospinal fluid confluence in the subarachnoid space at the lateral and ventral surface of the brain cortex at 3 h after the injection. By using this newly developed method, the brain ECS and ISF can be quantitatively measured simultaneously in the living brain, which will enhance the understanding of ISF and improve the efficiency of drug therapy via the brain interstitium.
文摘The respiratory burst of neutrophils is an important response in inflammation. The alterations in extracellular pH per se is not a sufficient trigger to the respiratory burst in neutrophils. While neutrophils in respose to conventional agonists, the respiratory burst in neutrophils is affected by the alterations in extracellular pH, and there is a direct relationship between intracellular and extracellular pH. O-· 2 production in neutrophils is decreased while H 2O 2 production is increased at acidic pH. O-· 2 release in neutrophils is enhanced at weak alkaline pH. Na+/H+ exchanger plays an important role in the regulation of the respiratory burst of neutrophils.
基金supported by the National Science Fund for Distinguished Young Scholars(61625102)the National Natural Science Foundation of China(61971011)。
文摘The smooth transportation of substances through the brain extracellular space(ECS)is crucial to maintaining brain function;however,the way this occurs under simulated microgravity remains unclear.In this study,tracer-based magnetic resonance imaging(MRI)and DECS-mapping techniques were used to image the drainage of brain interstitial fluid(ISF)from the ECS of the hippocampus in a tail-suspended hindlimb-unloading rat model at day 3(HU-3)and 7(HU-7).The results indicated that drainage of the ISF was accelerated in the HU-3 group but slowed markedly in the HU-7 group.The tortuosity of the ECS decreased in the HU-3 group but increased in the HU-7 group,while the volume fraction of the ECS increased in both groups.The diffusion rate within the ECS increased in the HU-3 group and decreased in the HU-7 group.The alterations to ISF drainage and diffusion in the ECS were recoverable in the HU-3 group,but neither parameter was restored in the HU-7 group.Our findings suggest that early changes to the hippocampal ECS and ISF drainage under simulated microgravity can be detected by tracer-based MRI,providing a new perspective for studying microgravity-induced nano-scale structure abnormities and developing neuroprotective approaches involving the brain ECS.
