PMC:6194691 / 35501-36763 JSONTXT

{"project":"MyTest","denotations":[{"id":"30340614-27836940-30706021","span":{"begin":183,"end":185},"obj":"27836940"},{"id":"30340614-28847942-30706022","span":{"begin":206,"end":208},"obj":"28847942"},{"id":"30340614-26837044-30706023","span":{"begin":1082,"end":1085},"obj":"26837044"},{"id":"30340614-25678956-30706024","span":{"begin":1103,"end":1105},"obj":"25678956"},{"id":"30340614-29101220-30706025","span":{"begin":1256,"end":1259},"obj":"29101220"}],"namespaces":[{"prefix":"_base","uri":"https://www.uniprot.org/uniprot/testbase"},{"prefix":"UniProtKB","uri":"https://www.uniprot.org/uniprot/"},{"prefix":"uniprot","uri":"https://www.uniprot.org/uniprotkb/"}],"text":"It is unclear how the flow required for the glymphatic hypothesis to be correct, at least 0.6 µL g−1 min−1 (see Proposal 3 above), could be driven through the parenchyma. Jin et al. [77] and Holter et al. [80] have calculated fluid flows within the parenchyma using, respectively, 2-D and 3-D models of the geometry and dimensions of the interstitial spaces. Jin et al. concluded that “little or no advective solute transport is predicted to occur with physiological paravascular pressure differences” taken to be \u003c 5 mmHg. (Strictly advection corresponds to flow while convection includes both flow and diffusion). Furthermore they concluded that the water permeability of the endfeet membrane facing the microvessels, i.e. the membrane containing Aqp4, could have little direct effect on water flow into the parenchyma.7 Jin et al. assumed that the ISF between the cells behaves as a free fluid with the viscosity of water. If instead ISF in the interstitial spaces in the brain has properties similar to those of extracellular fluid in tissues in the rest of the body (see [138, 139], discussion in [41] and,8 the pressure required for flow would be much larger than that calculated by Jin et al. making bulk flow (advection) even less likely (compare [140])."}

{"project":"2_test","denotations":[{"id":"30340614-27836940-30706021","span":{"begin":183,"end":185},"obj":"27836940"},{"id":"30340614-28847942-30706022","span":{"begin":206,"end":208},"obj":"28847942"},{"id":"30340614-26837044-30706023","span":{"begin":1082,"end":1085},"obj":"26837044"},{"id":"30340614-25678956-30706024","span":{"begin":1103,"end":1105},"obj":"25678956"},{"id":"30340614-29101220-30706025","span":{"begin":1256,"end":1259},"obj":"29101220"}],"text":"It is unclear how the flow required for the glymphatic hypothesis to be correct, at least 0.6 µL g−1 min−1 (see Proposal 3 above), could be driven through the parenchyma. Jin et al. [77] and Holter et al. [80] have calculated fluid flows within the parenchyma using, respectively, 2-D and 3-D models of the geometry and dimensions of the interstitial spaces. Jin et al. concluded that “little or no advective solute transport is predicted to occur with physiological paravascular pressure differences” taken to be \u003c 5 mmHg. (Strictly advection corresponds to flow while convection includes both flow and diffusion). Furthermore they concluded that the water permeability of the endfeet membrane facing the microvessels, i.e. the membrane containing Aqp4, could have little direct effect on water flow into the parenchyma.7 Jin et al. assumed that the ISF between the cells behaves as a free fluid with the viscosity of water. If instead ISF in the interstitial spaces in the brain has properties similar to those of extracellular fluid in tissues in the rest of the body (see [138, 139], discussion in [41] and,8 the pressure required for flow would be much larger than that calculated by Jin et al. making bulk flow (advection) even less likely (compare [140])."}