PMC:6194691 / 93898-95701 JSONTXT

{"project":"MyTest","denotations":[{"id":"30340614-5473139-30706267","span":{"begin":19,"end":22},"obj":"5473139"},{"id":"30340614-1182146-30706268","span":{"begin":41,"end":44},"obj":"1182146"},{"id":"30340614-1569138-30706269","span":{"begin":265,"end":268},"obj":"1569138"},{"id":"30340614-9422387-30706270","span":{"begin":270,"end":273},"obj":"9422387"},{"id":"30340614-11488534-30706270","span":{"begin":270,"end":273},"obj":"11488534"},{"id":"30340614-22324542-30706270","span":{"begin":270,"end":273},"obj":"22324542"},{"id":"30340614-5473139-30706271","span":{"begin":1071,"end":1074},"obj":"5473139"},{"id":"30340614-1182146-30706272","span":{"begin":1136,"end":1139},"obj":"1182146"},{"id":"30340614-9422387-30706273","span":{"begin":1339,"end":1342},"obj":"9422387"},{"id":"30340614-11488534-30706274","span":{"begin":1396,"end":1399},"obj":"11488534"}],"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":"Buschiazzo et al. [319] and Betz et al. [327] determined the total glucose in the parenchyma for different glucose concentrations in plasma (see Fig. 14). Subsequently NMR has been used to measure glucose content in conscious humans and lightly anaesthetized rats [334, 337–341]. The NMR results for humans and rats confirm under nearly physiological conditions (see Fig. 14) that brain glucose content continues to increase with plasma concentration for plasma concentrations up to at least 30 mM well above a typical resting value, 6 mM. They also confirm that the rates of glucose influx and efflux are respectively larger than and not much smaller than the rate of metabolism. Because influx and efflux substantially exceed the expected efflux via the perivascular route, the net flux across the blood–brain barrier is normally taken to be equal to CMRglc at steady-state.\nFig. 14 Four studies of brain glucose content versus glucose concentration in blood. In two studies glucose content was measured by chemical assay, a in anaesthetized rats by Buschiazzo et al. [319] and b in isolated perfused brains from dogs by Betz et al. [327]. In the latter it was assumed that brain water was 0.75 mL g−1. In the other two studies glucose content was determined by magnetic resonance spectroscopy, c in conscious humans by Gruetter et al. [337] and d in lightly anaesthetized rats by Choi et al. [338]. In all studies the glucose content continues to increase with plasma concentration even though it is known that the influx of glucose shows saturation. The explanation is that efflux also saturates and the increase in content must parallel the increase in plasma concentration in order for efflux to increase so that it is equal to influx minus the constant rate of glucose metabolism (see Appendix D)"}

{"project":"2_test","denotations":[{"id":"30340614-5473139-30706267","span":{"begin":19,"end":22},"obj":"5473139"},{"id":"30340614-1182146-30706268","span":{"begin":41,"end":44},"obj":"1182146"},{"id":"30340614-1569138-30706269","span":{"begin":265,"end":268},"obj":"1569138"},{"id":"30340614-9422387-30706270","span":{"begin":270,"end":273},"obj":"9422387"},{"id":"30340614-11488534-30706270","span":{"begin":270,"end":273},"obj":"11488534"},{"id":"30340614-22324542-30706270","span":{"begin":270,"end":273},"obj":"22324542"},{"id":"30340614-5473139-30706271","span":{"begin":1071,"end":1074},"obj":"5473139"},{"id":"30340614-1182146-30706272","span":{"begin":1136,"end":1139},"obj":"1182146"},{"id":"30340614-9422387-30706273","span":{"begin":1339,"end":1342},"obj":"9422387"},{"id":"30340614-11488534-30706274","span":{"begin":1396,"end":1399},"obj":"11488534"}],"text":"Buschiazzo et al. [319] and Betz et al. [327] determined the total glucose in the parenchyma for different glucose concentrations in plasma (see Fig. 14). Subsequently NMR has been used to measure glucose content in conscious humans and lightly anaesthetized rats [334, 337–341]. The NMR results for humans and rats confirm under nearly physiological conditions (see Fig. 14) that brain glucose content continues to increase with plasma concentration for plasma concentrations up to at least 30 mM well above a typical resting value, 6 mM. They also confirm that the rates of glucose influx and efflux are respectively larger than and not much smaller than the rate of metabolism. Because influx and efflux substantially exceed the expected efflux via the perivascular route, the net flux across the blood–brain barrier is normally taken to be equal to CMRglc at steady-state.\nFig. 14 Four studies of brain glucose content versus glucose concentration in blood. In two studies glucose content was measured by chemical assay, a in anaesthetized rats by Buschiazzo et al. [319] and b in isolated perfused brains from dogs by Betz et al. [327]. In the latter it was assumed that brain water was 0.75 mL g−1. In the other two studies glucose content was determined by magnetic resonance spectroscopy, c in conscious humans by Gruetter et al. [337] and d in lightly anaesthetized rats by Choi et al. [338]. In all studies the glucose content continues to increase with plasma concentration even though it is known that the influx of glucose shows saturation. The explanation is that efflux also saturates and the increase in content must parallel the increase in plasma concentration in order for efflux to increase so that it is equal to influx minus the constant rate of glucose metabolism (see Appendix D)"}