Association between leukocyte telomere length and sex by quantile regression analysis

ABSTRACT Introduction: Telomere length (TL) is a biomarker of cellular proliferative history. In healthy individuals, leukocyte TL shortens with age and associates with the lifespan of men and women. However, most of studies had used linear regression models to address the association of the TL attrition, aging and sex. Methods: We evaluated the association between the TL, aging and sex in a cohort of 180 healthy subjects by quantile regression. The TL of nucleated blood cells was measured by fluorescent in situ hypridization (flow-FISH) in a cohort of 89 men, 81 women, and 10 umbilical cord samples. The results were validated by quantitative polymerase chain reaction (qPCR) and compared to a linear regression analysis. Results: By quantile regression, telomere dynamics slightly differed between sexes with aging: women had longer telomeres at birth and slower attrition rate than men until the sixth decade of life; after that, TL eroded faster and became shorter than that in men. These differences were not observed by linear regression analysis, as the overall telomere attrition rates in women and men were similar (42 pb per year, p < 0.0001 vs. 45 pb kb per year, p < 0.0001). Also, qPCR did not recapitulate flow-FISH findings, as the telomere dynamics by qPCR followed a linear model. Conclusion: The quantile regression analysis accurately reproduced a third-orderpolynomial TL attrition rate in both women and men, but it depended on the technique applied to measure TL. The Flow-FISH reproduced the expected telomere dynamics through life and, differently from the qPCR, was able to detect the subtle TL variations associated with sex and aging.

Application of Flow Cytometry Combined Fluorescence in Situ Hybridization to Indentify the Lymphocyte Subtypies with Epstein-Barr Virus Infection / 中国实验血液学杂志

OBJECTIVE@#To establish the technique that take the advantages of flow cytometry combined fluorescence in situ hybridization (Flow-FISH) to identify the Epstein-Barr virus(EBV) infected lymphocyte subtypies in patients' peripheral blood sample.@*METHODS@#Peripheral Blood monocyte from 9 patients with EBV infection enrolled at Children's Hospital in Chongqing Medical University were isolated by Ficoll-paque centrifugal separation. The expressions of EBER1, EBER2 in cell were detected by qRT-PCR. The surface markers of cell were detected by Flow cytometry after staining with their antibodies. The cell was treated Fix-Permeabilization Buffer before hybridization with fluorescent labeled probe at 37 ℃ overnight. The cell status, surface markers and targeted mRNA are detected by flow cytometry and fluorescence microscope.@*RESULTS@#It was optimized that the Fix-Permeabilization Buffer and recipe with 0.2% Tween-20 were picked out as providing a good cell integrity and high resolution of surface markers. Hybridization with 20% formamide and 7% dextran sulfate at 37 ℃ overnight is the optimal hybridization condition as a good hybridization effect, a detectable cell integrity and a high resolution of cell markers under flow cytometry detection. Finally, upon the established Flow-FISH method, lymphocyte subpopulations of the EBV+ cells from cell lines and blood samples of patients were identified successfully.@*CONCLUSION@#A Flow-FISH technology is established, which can be applied in the identification of EBV infected cell subtypes. This research provides a foundmental for its application in clinical test in EBV+ related proliferative diseases.

Advances on the dynamics and measurement methods of telomere length in myelodysplastic syndromes / 白血病·淋巴瘤

Myelodysplastic syndromes (MDS) are a group of clonal disorders of hematopoietic stem cells.Recent studies have shown that the change of telomere length is closely related to the development and progression of MDS.Therefore,the dynamics of telomere length in MDS and the measurement methods of telomere length have been focused on gradually.Here the recent advances in this field were reviewed.