S Phase Cell Percentage Normalized BrdU Incorporation Rate, a New Parameter for Determining S Arrest

In this study, a new parameter, S phase cell percentage （S fraction） normalized BrdU （SFN-BrdU） incorporation rate, was introduced to detect $ arrest. The results showed a positive linear correlation between the BrdU incorporation rate and the S fraction in unperturbed 16HBE cells. Theoretical analysis indicated that only S arrest could result in a decrease in the SFN-BrdU incorporation rate. Additionally, the decrease in SFN-BrdU incorporation rate and the activation of DNA damage checkpoints further demonstrated that S arrest was induced by diethyl sulfate treatment of 16HBE cells. In conclusion, $FN-BrdU incorporation rate can be used to detecting S arrest.

Impacts of application patterns and incorporation rates of dredged Yellow River sediment on structure and infiltration of saline-alkali soil

Soil salinization is an issue of global concern.Despite recent evidence indicates that application of sediments into saline-alkali soil in Yellow River Delta as an additive can increase crop yield,its effects on soil structure and infiltration remain uncertain.In this study,the comprehensively analyses were conducted on the soil infiltration and microstructure of the soil treated with three sediment application layers(surface layer at 0-15 cm,lower layer at 15-30 cm,and plough layer at 0-30 cm)and four sediment incorporation rates(0,2%,5%and 10%),using soil column simulation experiment.Results indicated that the dredged Yellow River sediments can improve the infiltration capacity of saline-alkali soil;and the infiltration capacity increased with the rising sediment incorporation rate under the given application pattern.Compared with the control,applying dredged Yellow River sediments at 10%rate at lower layer and plough layer significantly facilitated the soil infiltration of the saline-alkali soil.Soil macro-porosity for T2,T5 and T10 was 26%,52%and 158%more than that for the control,respectively.This phenomenon was attributed to the increased soil macro-porosity,due to the improved soil microstructure with the incorporation of sediment into the saline-alkali soil.Moreover,the cumulative infiltration was fitted better with Kostiakov infiltration model than Horton and Philip models.

Study of intracellular anabolism of 5-fluorouracil and incorporation in nucleic acids based on an LC-HRMS method

5-Fluorouracil(5-FU)is an anticancer drug extensively used for different cancers.Intracellular metabolic activation leads to several nucleoside and nucleotide metabolites essential to exert its cytotoxic activity on multiple cellular targets such as enzymes,DNA and RNA.In this paper,we describe the development of a method based on liquid chromatography coupled with high resolution mass spectrometry suitable for the simultaneous determination of the ten anabolic metabolites(nucleoside,nucleotide and sugar nucleotide)of 5-FU.The chromatographic separationwas optimized on a porous graphitic carbon column allowing the analysis of the metabolites of 5-FU as well as endogenous nucleotides.The detection was performed on an Orbitrap■tandem mass spectrometer.Linearity of the method was verified in intracellular content and in RNA extracts.The limit of detection was equal to 12 pg injected on column for nucleoside metabolites of 5-FU and 150 pg injected on column for mono-and tri-phosphate nucleotide metabolites.Matrix effect was evaluated in cellular contents,DNA and RNA extracts for nucleoside and nucleotides metabolites.The method was successfully applied to i)measure the proportion of each anabolic metabolite of 5-FU in cellular contents,ii)follow the consequence of inhibition of enzymes on the endogenous nucleotide pools,iii)study the incorporation of metabolites of 5-FU into RNA and DNA,and iv)to determine the incorporation rate of 5-FUrd into 18 S and 28 S sub-units of rRNA.

Evaluation of Erythrocyte Iron Incorporation in Beijing Prepubertal Children Using a Single Stable Isotope Tracer Method

Objective To analyze the rate of erythrocyte iron incorporation and provided guidance for the iron nutrition for prepubertal children.Methods Fifty-seven prepubertal children of Beijing were involved in this study and each subject was orally administered 3 mg of 57 Fe twice daily to obtain a total of 30 mg 57 Fe after a 5-d period. The stable isotope ratios in RBCs were determined in 14 th day, 28 th day, 60 th day, and 90 th day. The erythrocyte incorporation rate in children was calculated using the stable isotope ratios, blood volume and body iron mass.Results The percentage of erythrocyte 57 Fe incorporation increased starting 14 th day, reached a peak at 60 d(boys: 19.67% ± 0.56%, girls: 21.33% ± 0.59%) and then decreased. The erythrocyte incorporation rates of 57 Fe obtained for girls in 60 th day was significantly higher than those obtained for boys(P < 0.0001).Conclusions The oral administration of 57 Fe to children can be used to obtain erythrocyte iron incorporation within 90 d. Prepubertal girls should begin to increase the intake of iron and further studies should pay more attention to the iron status in prepubertal children.