The distribution of ^(125)I recombinant E. coli L-asparaginase in tissues ororgans and the excretion in urine, feces and bile were studied with in vivo radioactive tracertechnique. The amount of radioactivity excreted...The distribution of ^(125)I recombinant E. coli L-asparaginase in tissues ororgans and the excretion in urine, feces and bile were studied with in vivo radioactive tracertechnique. The amount of radioactivity excreted in urine, feces and bile within 24 h afterintravenous administration of ^(125)I recombinant E. col L-asparaginase to rats was 68.95% ,4.44%and 5.36% of the dose respectively. ^(125)I recombinant E. coli L-asparaginase in plasma samples wasdetermined. The levels of structural intact molecule in plasma samples were evaluated by SDS-PAGEand bio-imaging analyzer system. Pharmacokinetic parameters were assessed with a model-dependentmethod. The concentration-time curves of recombinant E. coli L-asparaginase after intravenousinjection at 1 250 IU·kg^(-1), 2 500, IU·kg^(-1), 5 000 IU·kg^(-1) to rats were consistent withthe two-compartment model. The first and terminal elimination t_(1/2) were 0.52 ~ 0.63 h and 2.39 ~2.76 h respectively. AUC was linearly related to the doses. The results of distribution in tissuesor organs and excretion in urine suggested that the metabolites of the enzyme were cleared bymechanisms of urinary excretion. Pharmacokinetics parameters of recombinant E. coli L- asparaginasein rats are warranted for the design of future clinical trials.展开更多
A brunisolic soil collected from an erosive forest land (HF-1-1) and a yellow soil from an accumulative shallow basin (HF-6-1) in the watershed of Lake Hongfeng (HF) were used for activity measurements of 7Be, 137Cs, ...A brunisolic soil collected from an erosive forest land (HF-1-1) and a yellow soil from an accumulative shallow basin (HF-6-1) in the watershed of Lake Hongfeng (HF) were used for activity measurements of 7Be, 137Cs, 226Ra and 228Ra in different geochemical speciation. More than 85% of 7Be, 137Cs, 226Ra and 228Ra in the soils were bound to organic, Fe-Mn oxy-hydroxide and residual fractions. They could move with soil particles and be used as tracers for the erosion and/or accumulation of soil particles. 7Be geochemical speciation in the soils agreed with its trace for seasonal particle transport. 137Cs geochemical speciation was suitable for tracing soil particle accumulation and for sediment dating. 226Ra and 228Ra were combined in crystalline skeleton of clay minerals and mainly remained as residues in the soils and little was bound to the soluble, exchangeable and carbonate fractions. The differentiation of 226Ra/228Ra activity ratios in different geochemical fractions in the soils could be used as a parameter to trace accumulation and /or erosion of soil particles.展开更多
This paper outlines briefly the role of nuclear medicine in life sciences and health care. Molecular imaging by using isotopic tracers can noninvasively visualize the chemistry or hidden process in the cells and tissu...This paper outlines briefly the role of nuclear medicine in life sciences and health care. Molecular imaging by using isotopic tracers can noninvasively visualize the chemistry or hidden process in the cells and tissues inside the body, obtaining "functional" images to provide early information of any disease and revealing the secrets of life. The vitality of nuclear medicine is its ability to translate bench into new clinical application that can benefits the patients. Although nuclear medicine community in China has made significant achievement with a great effort since 1950s, there are many obstacles to future development. Recommended measures are proposed here in an attempt to solve our existing problems.展开更多
Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution. Soil erosion rates were quantified using the fallout radionuclide tr...Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution. Soil erosion rates were quantified using the fallout radionuclide tracer technique in Mojiagou Basin located on the outskirts of Changchun in Northeast China. The calculated soft erosion rates in the study area were 1.99 and 1.85 mm year-1 using 137Cs and excess 210pb （210Pbex） measurements, respectively. Both fallout radionuclides showed a similar tendency at downslope sites. All measured sites have experienced net erosion during the past 50 to 100 years. 137Cs and 210Pbex measurements were useful to quantify soil erosion rates on field and small basin scales. At this rate of erosion, the current fertile topsoil layer would be entirely removed within 70 years.展开更多
基金ProjectsupportedbytheNationalNinth FivePlanKeyProjectFoundation No 96 90 2 0 1 2 5
文摘The distribution of ^(125)I recombinant E. coli L-asparaginase in tissues ororgans and the excretion in urine, feces and bile were studied with in vivo radioactive tracertechnique. The amount of radioactivity excreted in urine, feces and bile within 24 h afterintravenous administration of ^(125)I recombinant E. col L-asparaginase to rats was 68.95% ,4.44%and 5.36% of the dose respectively. ^(125)I recombinant E. coli L-asparaginase in plasma samples wasdetermined. The levels of structural intact molecule in plasma samples were evaluated by SDS-PAGEand bio-imaging analyzer system. Pharmacokinetic parameters were assessed with a model-dependentmethod. The concentration-time curves of recombinant E. coli L-asparaginase after intravenousinjection at 1 250 IU·kg^(-1), 2 500, IU·kg^(-1), 5 000 IU·kg^(-1) to rats were consistent withthe two-compartment model. The first and terminal elimination t_(1/2) were 0.52 ~ 0.63 h and 2.39 ~2.76 h respectively. AUC was linearly related to the doses. The results of distribution in tissuesor organs and excretion in urine suggested that the metabolites of the enzyme were cleared bymechanisms of urinary excretion. Pharmacokinetics parameters of recombinant E. coli L- asparaginasein rats are warranted for the design of future clinical trials.
文摘A brunisolic soil collected from an erosive forest land (HF-1-1) and a yellow soil from an accumulative shallow basin (HF-6-1) in the watershed of Lake Hongfeng (HF) were used for activity measurements of 7Be, 137Cs, 226Ra and 228Ra in different geochemical speciation. More than 85% of 7Be, 137Cs, 226Ra and 228Ra in the soils were bound to organic, Fe-Mn oxy-hydroxide and residual fractions. They could move with soil particles and be used as tracers for the erosion and/or accumulation of soil particles. 7Be geochemical speciation in the soils agreed with its trace for seasonal particle transport. 137Cs geochemical speciation was suitable for tracing soil particle accumulation and for sediment dating. 226Ra and 228Ra were combined in crystalline skeleton of clay minerals and mainly remained as residues in the soils and little was bound to the soluble, exchangeable and carbonate fractions. The differentiation of 226Ra/228Ra activity ratios in different geochemical fractions in the soils could be used as a parameter to trace accumulation and /or erosion of soil particles.
文摘This paper outlines briefly the role of nuclear medicine in life sciences and health care. Molecular imaging by using isotopic tracers can noninvasively visualize the chemistry or hidden process in the cells and tissues inside the body, obtaining "functional" images to provide early information of any disease and revealing the secrets of life. The vitality of nuclear medicine is its ability to translate bench into new clinical application that can benefits the patients. Although nuclear medicine community in China has made significant achievement with a great effort since 1950s, there are many obstacles to future development. Recommended measures are proposed here in an attempt to solve our existing problems.
基金Supported by the National Basic Research Program(973 Program)of China(No.2007CB407205)the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KSCX1-YW-09-13)+1 种基金the National Key Technology R&D Program of China during the 12th Five-Year Plan Period(No.2011BAD31B00)the National Major Science and Technology Program of China for Water Pollution Control and Treatment(No.009ZX07106-03-01)
文摘Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution. Soil erosion rates were quantified using the fallout radionuclide tracer technique in Mojiagou Basin located on the outskirts of Changchun in Northeast China. The calculated soft erosion rates in the study area were 1.99 and 1.85 mm year-1 using 137Cs and excess 210pb （210Pbex） measurements, respectively. Both fallout radionuclides showed a similar tendency at downslope sites. All measured sites have experienced net erosion during the past 50 to 100 years. 137Cs and 210Pbex measurements were useful to quantify soil erosion rates on field and small basin scales. At this rate of erosion, the current fertile topsoil layer would be entirely removed within 70 years.
