Histopathology of the gut in rheumatic diseases

The gastrointestinal tract regulates the trafficking of macromolecules between the environment and the host through an epithelial barrier mechanism and is an important part of the immune system controlling the equilibrium between tolerance and immunity to non-self-antigens. Various evidence indicates that intestinal inflammation occurs in patients with rheumatic diseases. In many rheumatic diseases intestinal inflammation appears to be linked to dysbiosis and possibly represents the common denominator in the pathogenesis of different rheumatic diseases. The continuative interaction between dysbiosis and the intestinal immune system may lead to the aberrant activation of immune cells that can re-circulate from the gut to the sites of extraintestinal inflammation as observed in patients with ankylosing spondylitis. The exact contribution of genetic factors in the development of intestinal inflammation in rheumatic diseases needs to be clarified

Pathogenesis of polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is a chronic, inflammatory disorder of unknown cause, almost exclusively occurring in people aged over 50 and often associated with giant cell arteritis. The evidence that PMR occurs almost exclusively in individuals aged over 50 may indicate that age-related immune alterations in genetically predisposed subjects contribute to development of the disease. Several infectious agents have been investigated as possible triggers of PMR even though the results are inconclusive. Activation of the innate and adaptive immune systems has been proved in PMR patients as demonstrated by the activation of dendritic cells and monocytes/macrophages and the altered balance between Th17 and Treg cells. Disturbed B cell distribution and function have been also demonstrated in PMR patients suggesting a pathogenesis more complex than previously imagined. In this review we will discuss the recent findings regarding the pathogenesis of PMR

Anisotropic Anomalous Diffusion assessed in the human brain by scalar invariant indices

A new method to investigate anomalous diffusion in human brain is proposed. The method has been inspired by both the stretched-exponential model proposed by Hall and Barrick (HB) and DTI. Quantities extracted using HB method were able to discriminate different cerebral tissues on the basis of their complexity, expressed by the stretching exponent gamma and of the anisotropy of gamma across different directions. Nevertheless, these quantities were not defined as scalar invariants like mean diffusivity and fractional anisotropy, which are eigenvalues of the diffusion tensor. We hypotesize instead that the signal may be espressed as a simple stretched-exponential only along the principal axes of diffusion, while in a generic direction the signal is modeled as a combination of three different stretched-exponentials. In this way, we derived indices to quantify both the tissue anomalous diffusion and its anisotropy, independently of the reference frame of the experiment. We tested and compare our new method with DTI and HB approaches applying them to 10 healty subjects brain at 3T. Our experimental results show that our parameters are highly correlated to intrinsic local geometry when compared to HB indices. Moreover, they offer a different kind of contrast when compared to DTI outputs. Specifically, our indices show a higher capability to discriminate among different areas of the corpus callosum, which are known to be associated to different axonal densities.Comment: 21 pages, 6 figures, 2 table

Discovery of Griffiths phase in itinerant magnetic semiconductor Fe_{1-x}Co_xS_2

Critical points that can be suppressed to zero temperature are interesting because quantum fluctuations have been shown to dramatically alter electron gas properties. Here, the metal formed by Co doping the paramagnetic insulator FeS$_2$, Fe$_{1-x}$Co$_x$S$_2$, is demonstrated to order ferromagnetically at $x>x_c=0.01\pm0.005$ where we observe unusual transport, magnetic, and thermodynamic properties. We show that this magnetic semiconductor undergoes a percolative magnetic transition with distinct similarities to the Griffiths phase, including singular behavior at $x_c$ and zero temperature.Comment: 10 pages, 4 figure

Smooth pursuits decrease balance control during locomotion in young and older healthy females.

Dynamic balance control-characterised as movement of the trunk and lower limbs-was assessed during fixation of a fixed target, smooth pursuits and saccadic eye movements in ten young (22.9 ± 1.5 years) and ten older (72.1 ± 8.2 years) healthy females walking overground. Participants were presented with visual stimuli to initiate eye movements, and posture and gaze were assessed with motion analysis and eye tracking equipment. The results showed an increase in medial/lateral (ML) trunk movement (C7: p = 0.012; sacrum: p = 0.009) and step-width variability (p = 0.052) during smooth pursuits compared to a fixed target, with no changes for saccades compared to a fixed target. The elders demonstrated greater ML trunk movement (sacrum: p = 0.037) and step-width variability (p = 0.037) than the younger adults throughout, although this did not interact with the eye movements. The findings showed that smooth pursuits decreased balance control in young and older adults similarly, which was likely a consequence of more complicated retinal flow. Since healthy elders are typically already at a postural disadvantage, further decreases in balance caused by smooth pursuits are undesirable