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首页> 外文期刊>The Journal of maternal-fetal medicine >Ovine intramembranous pathway permeability: use of solute clearance to determine membrane porosity.
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Ovine intramembranous pathway permeability: use of solute clearance to determine membrane porosity.

机译：羊膜内途径通透性：利用溶质清除率确定膜的孔隙率。

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OBJECTIVE: The contribution of the fetal chorioamniotic membranes (i.e. the intramembranous pathway) to the regulation and maintenance of amniotic fluid (AF) volume and composition has yet to be completely understood. Knowledge of membrane permeability properties is vital to understanding how the intramembranous pathway contributes to the overall maintenance of AF homeostasis. Although there are significant data regarding the regulation of intramembranous water flow, there is little understanding of the regulation of intramembranous solute flow. In the present study, we sought to determine the effect of molecular weight or size of non-polar compounds on intramembranous solute movement in the ovine model. METHODS: Five singleton ovine fetuses (117 +/- 3 days) were chronically prepared with bladder, tracheal, amniotic cavity and femoral arterial and venous catheters and an esophageal occluder. The allantoic membranes were excised. After 5 days' recovery, AF volume was calculated by intraamniotic injection of 99Tc-labelled red blood cells (time -6 to 0 h). At time 0, AF exchange routes were limited to the intramembranous pathway by inflation of the esophageal occluder and external drainage of fetal urine and lung fluid. Following intra-amniotic injection of creatinine (Cr, 1 g, MW 11 000 Da, 4 A) and [125I]albumin (RISA, 250 microCi, MW 69 000 Da, 36 A), maternal and fetal plasma and AF samples were collected at timed intervals during the subsequent 5 h. AF solute clearance (Cl(x)) was determined by the changes in AF total solute content. RESULTS: Cr and RISA disappeared from the AF with a corresponding increase in fetal, though not maternal, plasma levels. The mean Cl(Cr) was significantly greater than Cl(RISA) (2.0 +/- 0.3 ml/min vs. 1.0 +/- 0.2 ml/min; p < 0.04). CONCLUSION: Solute clearance from the amniotic cavity is inversely proportional to solute molecular weight/size. Although the membrane comprising the ovine intramembranous pathway is size restrictive, membrane pores allow passage of non-polar solutes up to 36 A. Knowledge of membrane permeability characteristics is essential for the utilization of the intramembranous pathway for fetal therapeutics.
机译：目的：胎儿绒膜羊膜（即膜内途径）对羊水（AF）体积和组成的调节和维持的作用尚未完全了解。膜通透性的知识对于理解膜内途径如何有助于维持AF稳态整体至关重要。尽管有大量有关膜内水流调节的数据，但对膜内溶质流调节的了解很少。在本研究中，我们试图确定分子量或非极性化合物的大小对绵羊模型中膜内溶质运动的影响。方法：采用膀胱，气管，羊膜腔，股动脉和静脉导管和食道封堵器，长期准备5例单胎绵羊胎儿（117 +/- 3天）。切除尿囊膜。恢复5天后，通过羊膜内注射99Tc标记的红细胞（时间-6至0小时）计算AF体积。在时间0，通过食管封堵器的充气以及胎儿尿液和肺液的外部引流，AF交换途径仅限于膜内途径。羊膜内注射肌酐（Cr，1 g，MW 11000 Da，4 A）和[125I]白蛋白（RISA，250 microCi，MW 69 000 Da，36 A）后，收集母体和胎儿血浆和AF样品在随后的5小时内定时间隔。 AF溶质清除率（Cl（x））由AF总溶质含量的变化确定。结果：房颤中铬和里沙（RISA）从AF中消失，胎儿（而非母体）血浆水平相应升高。平均Cl（Cr）明显大于Cl（RISA）（2.0 +/- 0.3 ml / min与1.0 +/- 0.2 ml / min; p <0.04）。结论：从羊膜腔清除的溶质与溶质的分子量/大小成反比。尽管包含绵羊膜内途径的膜是大小受限的，但膜孔允许非极性溶质通过高达36A。膜渗透性特性的知识对于利用膜内途径进行胎儿治疗至关重要。

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