Gene therapy: is IL2RG oncogenic in T-cell development?

The gene IL2RG encodes the gamma-chain of the interleukin-2 receptor and is mutated in patients with X-linked severe combined immune deficiency (X-SCID). Woods et al. report the development of thymus tumours in a mouse model of X-SCID after correction by lentiviral overexpression of IL2RG and claim that these were caused by IL2RG itself. Here we find that retroviral overexpression of IL2RG in human CD34+ cells has no effect on T-cell development, whereas overexpression of the T-cell acute lymphoblastic leukaemia (T-ALL) oncogene LMO2 leads to severe abnormalities. Retroviral expression of IL2RG may therefore not be directly oncogenic--rather, the restoration of normal signalling by the interleukin-7 receptor to X-SCID precursor cells allows progression of T-cell development to stages that are permissive for the pro-leukaemic effects of ectopic LMO2.     

Effect of partition coefficient on microsegregation during solidification of aluminium alloys

In the modeling of microsegregation, the partition coefficient is usually calculated using data from the equilibrium phase diagrams. The aim of this study was to experimentally and theoretically analyze the partition coefficient in binary aluminum-copper alloys. The samples were analyzed by differential thermal analysis (DTA), which were melted and quenched from different temperatures during solidification. The mass fraction and composition of phases were measured by image processing and scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDS) unit. These data were used to calculate as the experimental partition coefficients with four different methods. The experimental and equilibrium partition coefficients were used to model the concentration profile in the primary phase. The modeling results show that the profiles calculated by the experimental partition coefficients are more consistent with the experimental profiles, compared to those calculated using the equilibrium partition coefficients.