Franny Jongbloed

160 CHAPTER 6 Relative telomere length The relative telomere length of peripheral blood T-cells was determined by flow fluorescent in situ hybridization (flowFISH) technique, as described previously 15 . By using the subcell line 1301 of CCRF-CEM (known for its long telomeres) as a reference, a relative telomere length was calculated using the following formula: RTL = (median FL1 sample cells with probe -median FL1 sample cells without probe) × DNA index of control (=2) cells × 100 (median FL1 control cells with probe -median FL1 control cells without probe) × DNA index of sample (=1) cells Statistical analysis Statistics were computed with use of SPSS version 23 (IBM Corp, released 2015, IBM SPSS Statistics for Mac, Version 23.0, Armonk, NY: IBM Corp), and GraphPad Prism (GraphPad Software Inc., version 5.01). For all individual parameters, median and interquartile ranges were computed. Comparison of more than two parameters was done via One-Way ANOVA, considering normal distribution as tested by the Gaussian approximation. Related samples from the same patient were analyzed via the related-samples Friedman’s test. Prior to bariatric surgery a multivariate analysis was computed via general linear models option in SPSS, considering the Wilks’ Lambda test to evaluate which variables contributed to T-cell characteristics measured in the circulation. Figures were made in Graphpad. For all parameters, P< 0.05 was considered significant.