420 research outputs found
Recommended from our members
Association between Psychotic Symptoms and Cortical Thickness Reduction across the Schizophrenia Spectrum
The current study provides a complete MRI analysis of thickness throughout the cerebral cortical mantle in patients with schizophrenia (SZ) and rigorously screened and matched unaffected relatives and controls and an assessment of its relation to psychopathology and subjective cognitive function. We analyzed 3D-anatomical magnetic resonance imaging data sets, obtained at 3 Tesla, from three different subject groups: 25 SZ patients, 29 first-degree relatives and 37 healthy control subjects. We computed whole-brain cortical thickness using the Freesurfer software and assessed group differences. We also acquired clinical and psychometric data. The results showed markedly reduced cortical thickness in SZ patients compared with controls, most notably in the frontal and temporal lobes, in the superior parietal lobe and several limbic areas, with intermediate levels of cortical thickness in relatives. In both patients and relatives, we found an association between subjective cognitive dysfunction and reduced thickness of frontal cortex, and predisposition towards hallucinations and reduced thickness of the superior temporal gyrus. Our findings suggest that changes in specific cortical areas may predispose to specific symptoms, as exemplified by the association between temporal cortex thinning and hallucinations
The Historical Representation of Native Americans within Primary- and Intermediate-Level Trade Books
State and national education initiatives require significant changes for public schools beginning at the earliest grade levels and within all content areas. Two relevant changes are the increase of non-fiction in English/language arts and the mandate for diverse texts within history/social studies. History-based trade books are a logical resource for both curricula. Teachers must rely on their discretion when selecting trade books because the initiatives do not provide curricular support. Research indicates trade books’ cultural representation and historical representation are inconsistent, yet there is a need for further research as just over a dozen empirical studies have been completed. This study examines how Native Americans are historically and culturally represented within children’s literature. It juxtaposes findings for trade books intended for primary-level and intermediate-level elementary students. Important findings include the absence of tribal names, omission of historical connections with European colonists and American citizens, an apparent decline recent publications of trade books centered on Native Americans, and a robust representation of distinct cultural traits. Teachers are offered suggestions for instructional procedures and in selection of supplementary primary sources to assist in balancing the misrepresentations
Enteropathogenic E. coli, Salmonella, and Shigella: masters of host cell cytoskeletal exploitation.
Bacterial pathogens have evolved numerous strategies to exploit their host's cellular processes so that they can survive and persist. Often, a bacterium must adhere very tightly to the cells and mediate its effects extracellularly, or it must find a way to invade the host's cells and survive intracellularly. In either case, the pathogen hijacks the host's cytoskeleton. The cytoskeleton provides a flexible framework for the cell and is involved in mediating numerous cellular functions, from cell shape and structure to programmed cell death. Altering the host cytoskeleton is crucial for mediating pathogen adherence, invasion, and intracellular locomotion. We highlight recent advances in the pathogenesis of enteropathogenic Escherichia coli, Salmonella Typhimurium, and Shigella flexneri. Each illustrates how bacterial pathogens can exert dramatic effects on the host cytoskeleton
Sequential development of interleukin 2–dependent effector and regulatory T cells in response to endogenous systemic antigen
Transfer of naive antigen-specific CD4+ T cells into lymphopenic mice that express an endogenous antigen as a systemic, secreted protein results in severe autoimmunity resembling graft-versus-host disease. T cells that respond to this endogenous antigen develop into effector cells that cause the disease. Recovery from this disease is associated with the subsequent generation of FoxP3+CD25+ regulatory cells in the periphery. Both pathogenic effector cells and protective regulatory cells develop from the same antigen-specific T cell population after activation, and their generation may occur in parallel or sequentially. Interleukin (IL)-2 plays a dual role in this systemic T cell reaction. In the absence of IL-2, the acute disease is mild because of reduced T cell effector function, but a chronic and progressive disease develops late and is associated with a failure to generate FoxP3+ regulatory T (T reg) cells in the periphery. Thus, a peripheral T cell reaction to a systemic antigen goes through a phase of effector cell–mediated pathology followed by T reg cell–mediated recovery, and both require the growth factor IL-2
Role of IL-17 and regulatory T lymphocytes in a systemic autoimmune disease
To explore the interactions between regulatory T cells and pathogenic effector cytokines, we have developed a model of a T cell–mediated systemic autoimmune disorder resembling graft-versus-host disease. The cytokine responsible for tissue inflammation in this disorder is interleukin (IL)-17, whereas interferon (IFN)-γ produced by Th1 cells has a protective effect in this setting. Because of the interest in potential therapeutic approaches utilizing transfer of regulatory T cells and inhibition of the IL-2 pathway, we have explored the roles of these in the systemic disease. We demonstrate that the production of IL-17 and tissue infiltration by IL-17–producing cells occur and are even enhanced in the absence of IL-2. Regulatory T cells favor IL-17 production but prevent the disease when administered early in the course by suppressing expansion of T cells. Thus, the pathogenic or protective effects of cytokines and the therapeutic capacity of regulatory T cells are crucially dependent on the timing and the nature of the disease
Aldebaran's angular diameter: how well do we know it?
The bright, well-known K5 giant Aldebaran, alpha Tau, is probably the star
with the largest number of direct angular diameter determinations, achieved
over a long time by several authors using various techniques. In spite of this
wealth of data, or perhaps as a direct result of it, there is not a very good
agreement on a single angular diameter value. This is particularly unsettling
if one considers that Aldebaran is also used as a primary calibrator for some
angular resolution methods, notably for optical and infrared long baseline
interferometry. Directly connected to Aldebaran's angular diameter and its
uncertainties is its effective temperature, which also has been used for
several empirical calibrations. Among the proposed explanations for the
elusiveness of an accurate determination of the angular diameter of Aldebaran
are the possibility of temporal variations as well as a possible dependence of
the angular diameter on the wavelength. We present here a few, very accurate
new determinations obtained by means of lunar occultations and long baseline
interferometry. We derive an average value of 19.96+-0.03 milliarcseconds for
the uniform disk diameter. The corresponding limb-darkened value is 20.58+-0.03
milliarcseconds, or 44.2+-0.9 R(sun). We discuss this result, in connection
with previous determinations and with possible problems that may affect such
measurements.Comment: 8 pages, 4 figures, accepted for publication in A&
Altered apolipoprotein C expression in association with cognition impairments and hippocampus volume in schizophrenia and bipolar disorder
Proteomic analyses facilitate the interpretation of molecular biomarker probes which are very helpful in diagnosing schizophrenia (SZ). In the current study, we attempt to test whether potential differences in plasma protein expressions in SZ and bipolar disorder (BD) are associated with cognitive deficits and their underlying brain structures. Forty-two plasma proteins of 29 SZ patients, 25 BD patients and 93 non-clinical controls were quantified and analysed using multiple reaction monitoring-based triple quadrupole mass spectrometry approach. We also computed group comparisons of protein expressions between patients and controls, and between SZ and BD patients, as well. Potential associations of protein levels with cognitive functioning (psychomotor speed, executive functioning, crystallised intelligence) as well as underlying brain volume in the hippocampus were explored, using bivariate correlation analyses. The main finding of this study was that apolipoprotein expression differed between patients and controls and that these alterations in both disease groups were putatively related to cognitive impairments as well as to hippocampus volumes. However, none of the protein level differences were related to clinical symptom severity. In summary, altered apolipoprotein expression in BD and SZ was linked to cognitive decline and underlying morphological changes in both disorders. Our results suggest that the detection of molecular patterns in association with cognitive performance and its underlying brain morphology is of great importance for understanding of the pathological mechanisms of SZ and BD, as well as for supporting the diagnosis and treatment of both disorders
Sliding set-points of immune responses for therapy of autoimmunity
Although recent developments in the treatment of autoimmune disease have dramatically improved patient outcomes, these medications are not curative. Two studies in this issue demonstrate the feasibility of curing spontaneous autoimmunity in animal models via short-term enhancement of naturally arising regulatory T (T reg) cells, a subset of CD4+ T cells needed for maintaining self-tolerance. Importantly, these therapies seemed to generate a new equilibrium, or “set-point,” at which self-tissue damage no longer occurred long after the drug was eliminated from the body
- …