Bar-Ilan University

About: Bar-Ilan University is a education organization based out in Ramat Gan, Israel. It is known for research contribution in the topics: Population & Poison control. The organization has 12835 authors who have published 34964 publications receiving 995648 citations. The organization is also known as: Bar Ilan University & BIU.

TOX reinforces the phenotype and longevity of exhausted T cells in chronic viral infection.

Abstract: Cytotoxic T cells are essential mediators of protective immunity to viral infection and malignant tumours and are a key target of immunotherapy approaches. However, prolonged exposure to cognate antigens often attenuates the effector capacity of T cells and limits their therapeutic potential1-4. This process, known as T cell exhaustion or dysfunction1, is manifested by epigenetically enforced changes in gene regulation that reduce the expression of cytokines and effector molecules and upregulate the expression of inhibitory receptors such as programmed cell-death 1 (PD-1)5-8. The underlying molecular mechanisms that induce and stabilize the phenotypic and functional features of exhausted T cells remain poorly understood9-12. Here we report that the development and maintenance of populations of exhausted T cells in mice requires the thymocyte selection-associated high mobility group box (TOX) protein13-15. TOX is induced by high antigen stimulation of the T cell receptor and correlates with the presence of an exhausted phenotype during chronic infections with lymphocytic choriomeningitis virus in mice and hepatitis C virus in humans. Removal of its DNA-binding domain reduces the expression of PD-1 at the mRNA and protein level, augments the production of cytokines and results in a more polyfunctional T cell phenotype. T cells with this deletion initially mediate increased effector function and cause more severe immunopathology, but ultimately undergo a massive decline in their quantity, notably among the subset of TCF-1+ self-renewing T cells. Altogether, we show that TOX is a critical factor for the normal progression of T cell dysfunction and the maintenance of exhausted T cells during chronic infection, and provide a link between the suppression of effector function intrinsic to CD8 T cells and protection against immunopathology.

Scaling behaviour of heartbeat intervals obtained by wavelet-based time-series analysis

Abstract: BIOLOGICAL time-series analysis is used to identify hidden dynamical patterns which could yield important insights into underlying physiological mechanisms. Such analysis is complicated by the fact that biological signals are typically both highly irregular and non-stationary, that is, their statistical character changes slowly or intermittently as a result of variations in background influences1–3. Previous statistical analyses of heartbeat dynamics4–6 have identified long-range correlations and power-law scaling in the normal heartbeat, but not the phase interactions between the different frequency components of the signal. Here we introduce a new approach, based on the wavelet transform and an analytic signal approach, which can characterize non-stationary behaviour and elucidate such phase interactions. We find that, when suitably rescaled, the distributions of the variations in the beat-to-beat intervals for all healthy subjects are described by a single function stable over a wide range of timescales. However, a similar scaling function does not exist for a group with cardiopulmonary instability caused by sleep apnoea. We attribute the functional form of the scaling observed in the healthy subjects to underlying nonlinear dynamics, which seem to be essential to normal heart function. The approach introduced here should be useful in the analysis of other nonstationary biological signals.

Shape-Controlled Synthesis of Silver Nanoparticles by Pulse Sonoelectrochemical Methods

Abstract: Shaped silver nanoparticles with spheres, rods, and dendrites have been prepared by a pulse sonoelectrochemical technique from an aqueous solution of AgNO3 in the presence of nitrilotriacetate N(CH2COOH)3-NTA. The silver nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction, and absorption spectroscopy. The effects of electrosonic time on particle shape have been discussed. It was found that the concentration of AgNO3 and NTA affects the shape of the nanoparticles.