Screening and Verification of Antioxidant Small Molecular Compounds for Expansion of Human Hematopoietic Stem Cells Ex Vitro / 中国实验血液学杂志

OBJECTIVE@#To screen the antioxidant small molecular compounds with optimal efficiency of expansing the human hematopoietic stem cells (hHSC) In vitro based on antioxidant small molecular compound database of LKT laboratory, and to verify the effects of these compounds on the biological functions of hHSC.@*METHODS@#The umbilial cord blood CD34 cells were enriched by using the MACS beads; the absolute number and percentage of CD34 cells and CD34 CD49f cells were detected by high throughput flow cytometry after culture of hHSC with compounds in vitro for 1 week, the SR1 (1 μmol/L) was used as positive control, the candidate compounds were screened out; then 4 compounds were selected for follow-up experiments by comprehensive evaluation of concentration, safety and expansion efficacy, the optimal used concentrations of selected compounds were determined through the concentration gradient analysis, and CFC short-term colony-forming cell test was performed by using the determined concentration so as to verify the effect of compounds on the self-renewal, multilineage differentiation.@*RESULTS@#Out of 85 antioxidant small molecular compounds, 4 compounds (C2968, D3331, B1753 and B3358) with obvious expansion efficacy for CD34 cells and CD34 CD49f cells were screened out by high throughput flow cytometry; their optimal concentrations of 4 compounds were 0.5 μmol/L for C2968, 1.5 μmol/L for D3331 and 1.5 μmol/L for B1753 and 15 μmol/L for B3358. The CFC assay showed the colony formation number in compound-treated group significantly increased as compared with control group, moreover the self-renewal and multilineage differentiation were maintained.@*CONCLUSION@#The antioxidant small molecular compounds C2968 (0.5 μmol/L), D3331 (1.5 μmol/L), B1753 (1.5 μmol/L) and B3358 (1.5 μmol/L) possess good expansion efficacy for hHSC, they can maintain hHSC self-renewal, at the same time ensure the multilineage differentiation potentiality of hHSC.

Ex vivo Culture System of Single Human Hematopoietic Stem Cell Used to Screan the Small Molecular Compounds / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore an efficient, stable system and method to verify the regulation effect of small molecule compounds on human hematopoietic stem cells (hHSC).</p><p><b>METHODS</b>By using combination of flow cytometry with study results of surface markers on hHSC, and optimation of sorting process for further studying the effect of small molecular compounds on stem property of hHSC, the single hHSC was treated with published small molecular compounds such as SR1 and UM171 which possess the expansion effect. After treating with hHSC for 14 d, the flow cytometric analysis of cell phenotypes and cell morphologic observation were performed, at the same time the hematopoietic function of cultured hHSC was verified by colony-forming cell (CFC) test and cobblestone area forming cell (CAFC) test.</p><p><b>RESULTS</b>The effects of SR1 and UM171 and their compositions in multi-cell culture were consistent with the published data, therefore the useful concentration of compounds were obtained. The results of multiparameter sorting of single cell (CD34+ CD38- CD45RA- CD90+ CD49f+) and ex vivo culture were consistent with the results of bulk cell culture. The results of cell phenotype analysis was in accordance with flow cytometric results. In addition, CFC test and CAFC test revealed that the colony-forming ability in treated group was significantly higher than that in control group (P<0.05).</p><p><b>CONCLUSION</b>The rapid, efficient stably amplified and short-time culture system for single hHSC and method for varifying the effect of small molecular compounds are established, which provides platform for screening small molecular compounds and lays the foundation for further study of hHSC expansion.</p>

Comparison of cryoablation and radiofrequency ablation for treating atrioventricular nodal reentrant tachycardia / 中华心血管病杂志

<p><b>OBJECTIVE</b>To compare the efficacy and safety between cryoablation (Cryo) and radiofrequency (RF) ablation for treating patients with atrioventricular nodal reentrant tachycardia (AVNRT).</p><p><b>METHODS</b>Patients with AVNRT (n = 304) were divided into Cryo group (n = 67) and RF group (n = 237). The procedure success rate, complete slow pathway block rate, atrioventricular block rate and relapse rate were compared between two groups.</p><p><b>RESULTS</b>There was no statistically difference between 2 groups in the success rate (Cryo group 98.5% vs RF group 97.0%, P = 0.820), complete slow pathway block rate (Cryo group 98.5% vs RF group 91.6%, P = 0.088), atrioventricular block rate (Cryo group 0 vs RF group 2.5%, P = 0.413), relapse rate (Cryo group 0 vs RF group 1.7%, P = 0.643). But Cryo group had more advantage than RF group.</p><p><b>CONCLUSION</b>Efficacy and safety were comparable between cryoablation and radiofrequency ablation for treating patients with AVNRT.</p>