Introduction: β<sub>2</sub>-microglobulin and prolactin are medium-molecular-weight toxins. We believe that the rate of removal of these molecules, using filters with two different surfaces, in post- and ...Introduction: β<sub>2</sub>-microglobulin and prolactin are medium-molecular-weight toxins. We believe that the rate of removal of these molecules, using filters with two different surfaces, in post- and pre-dilution haemodiafiltration, will be of interest to the literature. Methods: We studied, in 12 haemodialyzed patients, the removal of those, with filter with surface of 2.5 m<sup>2</sup> (Group A) or 2.1 m<sup>2</sup> (Group B) with post-dilution haemodiafiltration, and with a filter with surface 2.5 m<sup>2</sup> with pre-dilution (Group C). Results: Satisfactory removal of β<sub>2</sub>-microglobulin (best with post-dilution) was found, and a good rate of removal of prolactin without the filter surface played a role in both cases. Conclusion: The elimination of β<sub>2</sub>-microglobulin in post-dilution is not affected by the filter surface area. Pre-dilution achieves removal of β<sub>2</sub>-microglobulin, less than that of post-dilution. Prolactin was removed satisfactorily regardless of the filter surface in post-dilution, and its removal appears to be less than that of β<sub>2</sub>-microglobulin.展开更多
Na+/K+-ATPase (EC 3.6.1.3) is an important membrane-bound enzyme. By using microcalorimetry, the thermokinetic method was developed to kinetic studies on Na+/K+-ATPase for the first time. Compared with other ones, the...Na+/K+-ATPase (EC 3.6.1.3) is an important membrane-bound enzyme. By using microcalorimetry, the thermokinetic method was developed to kinetic studies on Na+/K+-ATPase for the first time. Compared with other ones, the method provided accurate measurements of not only thermodynamic data but also the kinetic data. At 310.15 K and pH=7.4, the molar reaction enthalpy rHm was measured as (-40.408±1.9) kJ·mol-1. The Michaelis constant Km was determined to be (0.479±0.020)×10-3 mol·L-1 and consistent with literature figure which is about 0.5×10-3 mol·L-1. The maximum velocity Vmax obtained was (0.681±0.026) 靘ol Pi·min-1·mg protein-1. All of the data have good repeatability and self-consistency. The reliability of thermokinetic method was verified by the experimental results and further confirmed by colorimetric studies. Moreover, the effect of enzyme pre-dilution on its activities was also investigated.展开更多
文摘Introduction: β<sub>2</sub>-microglobulin and prolactin are medium-molecular-weight toxins. We believe that the rate of removal of these molecules, using filters with two different surfaces, in post- and pre-dilution haemodiafiltration, will be of interest to the literature. Methods: We studied, in 12 haemodialyzed patients, the removal of those, with filter with surface of 2.5 m<sup>2</sup> (Group A) or 2.1 m<sup>2</sup> (Group B) with post-dilution haemodiafiltration, and with a filter with surface 2.5 m<sup>2</sup> with pre-dilution (Group C). Results: Satisfactory removal of β<sub>2</sub>-microglobulin (best with post-dilution) was found, and a good rate of removal of prolactin without the filter surface played a role in both cases. Conclusion: The elimination of β<sub>2</sub>-microglobulin in post-dilution is not affected by the filter surface area. Pre-dilution achieves removal of β<sub>2</sub>-microglobulin, less than that of post-dilution. Prolactin was removed satisfactorily regardless of the filter surface in post-dilution, and its removal appears to be less than that of β<sub>2</sub>-microglobulin.
基金Project supported by the National Natural Science Foundation of China (No. 30070200).
文摘Na+/K+-ATPase (EC 3.6.1.3) is an important membrane-bound enzyme. By using microcalorimetry, the thermokinetic method was developed to kinetic studies on Na+/K+-ATPase for the first time. Compared with other ones, the method provided accurate measurements of not only thermodynamic data but also the kinetic data. At 310.15 K and pH=7.4, the molar reaction enthalpy rHm was measured as (-40.408±1.9) kJ·mol-1. The Michaelis constant Km was determined to be (0.479±0.020)×10-3 mol·L-1 and consistent with literature figure which is about 0.5×10-3 mol·L-1. The maximum velocity Vmax obtained was (0.681±0.026) 靘ol Pi·min-1·mg protein-1. All of the data have good repeatability and self-consistency. The reliability of thermokinetic method was verified by the experimental results and further confirmed by colorimetric studies. Moreover, the effect of enzyme pre-dilution on its activities was also investigated.
