Vessel-Wall Magnetic Resonance Imaging of Intracranial Atherosclerotic Plaque and Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction: Vessel-wall magnetic resonance imaging (MRI) has been suggested as a valuable tool for assessing intracranial arterial stenosis with additional diagnostic features. However, there is limited conclusive evidence on whether vessel-wall MR imaging of intracranial atherosclerotic plaques provides valuable information for predicting vulnerable lesions. We conducted this systematic review and meta-analysis to evaluate which characteristics of intracranial-plaque on vessel-wall MRI are markers of culprit lesions.Methods: The MEDLINE, EMBASE, and Cochrane Library of Clinical Trials databases were searched for studies reporting the association between vessel-wall MRI characteristics of intracranial plaque and corresponding stroke events. Odds ratios (ORs) for the prevalence of stroke with intracranial-plaque MRI characteristics were pooled in a meta-analysis using a random-effects model.Results: Twenty studies were included in this review. We found a significant association between plaque enhancement (OR, 10.09; 95% CI, 5.38–18.93), positive remodeling (OR, 6.19; 95% CI, 3.22–11.92), and plaque surface irregularity (OR, 3.94; 95% CI, 1.90–8.16) with stroke events. However, no significant difference was found for the presence of eccentricity (OR, 1.22; 95% CI, 0.51–2.91).Conclusion: Based on current evidence, intracranial plaque contrast enhancement, positive remodeling, and plaque irregularity on MRI are associated with increased risk of stroke events. Our findings support the design of future studies on intracranial-plaque MRI and decision making for the management of intracranial atherosclerotic plaques

Properties of Central Caustics in Planetary Microlensing

To maximize the number of planet detections, current microlensing follow-up observations are focusing on high-magnification events which have a higher chance of being perturbed by central caustics. In this paper, we investigate the properties of central caustics and the perturbations induced by them. We derive analytic expressions of the location, size, and shape of the central caustic as a function of the star-planet separation, $s$, and the planet/star mass ratio, $q$, under the planetary perturbative approximation and compare the results with those based on numerical computations. While it has been known that the size of the planetary caustic is \propto \sqrt{q}, we find from this work that the dependence of the size of the central caustic on $q$ is linear, i.e., \propto q, implying that the central caustic shrinks much more rapidly with the decrease of $q$ compared to the planetary caustic. The central-caustic size depends also on the star-planet separation. If the size of the caustic is defined as the separation between the two cusps on the star-planet axis (horizontal width), we find that the dependence of the central-caustic size on the separation is \propto (s+1/s). While the size of the central caustic depends both on $s$ and q, its shape defined as the vertical/horizontal width ratio, R_c, is solely dependent on the planetary separation and we derive an analytic relation between R_c and s. Due to the smaller size of the central caustic combined with much more rapid decrease of its size with the decrease of q, the effect of finite source size on the perturbation induced by the central caustic is much more severe than the effect on the perturbation induced by the planetary caustic. Abridged.Comment: 5 pages, 4 figures, ApJ accepte

Etiologic and epidemiologic analysis of bacterial infectious upper respiratory disease in Thoroughbred horses at the Seoul Race Park

Infectious upper respiratory disease (IURD) of Thoroughbred racehorses has been a frequent problem (29.6% of incidence) at the Seoul Race Park (Korea). Risk factors for IURD include the season with a high transfer rate (summer and fall), the stabling period (≤ 3 months), and age (2 to 3 years old), suggesting that the movement and new environment may have depressed the immune system of the horses and decreased their ability to respond properly to pathogens. The bacterial strains (n = 98) isolated from IURD horses included Pseudomonas spp., Escherichia coli, Staphylococcus spp., Streptococcus equi subsp. equi and zooepidemicus

Gliosarcoma of the Cerebellar Hemisphere: a Case Report and Review of the Literature

Gliosarcoma is a rare central nervous system tumor usually located in the supratentorial area. Here we report a rare case of a gliosarcoma that developed in the cerebellar hemisphere in a 70-year-old woman. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain revealed an infratentorial mass of which radiological features were similar to those of glioblastoma. The tumor was diagnosed by pathology as a gliosarcoma. Though rare, gliosarcoma should be considered in the differential diagnosis of infratentorial tumors with radiological features of glioblastoma or metastasis in elderly patients

Controlling the Magnetic Anisotropy of the van der Waals Ferromagnet Fe3GeTe2 through Hole Doping.

Identifying material parameters affecting properties of ferromagnets is key to optimized materials that are better suited for spintronics. Magnetic anisotropy is of particular importance in van der Waals magnets, since it not only influences magnetic and spin transport properties, but also is essential to stabilizing magnetic order in the two-dimensional limit. Here, we report that hole doping effectively modulates the magnetic anisotropy of a van der Waals ferromagnet and explore the physical origin of this effect. Fe3-xGeTe2 nanoflakes show a significant suppression of the magnetic anisotropy with hole doping. Electronic structure measurements and calculations reveal that the chemical potential shift associated with hole doping is responsible for the reduced magnetic anisotropy by decreasing the energy gain from the spin-orbit induced band splitting. Our findings provide an understanding of the intricate connection between electronic structures and magnetic properties in two-dimensional magnets and propose a method to engineer magnetic properties through doping

Valproic Acid Downregulates the Expression of MGMT and Sensitizes Temozolomide-Resistant Glioma Cells

Temozolomide (TMZ) has become a key therapeutic agent in patients with malignant gliomas; however, its survival benefit remains unsatisfactory. Valproic acid (VPA) has emerged as an anticancer drug via inhibition of histone deacetylases (HDACs), but the therapeutic advantages of a combination with VPA and TMZ remain poorly understood. The main aim of the present study was to determine whether an antitumor effect could be potentiated by a combination of VPA and TMZ, especially in TMZ-resistant cell lines. A combination of VPA and TMZ had a significantly enhanced antitumor effect in TMZ-resistant malignant glioma cells (T98 and U138). This enhanced antitumor effect correlated with VPA-mediated reduced O6-methylguanine-DNA methyltransferase (MGMT) expression, which plays an important role in cellular resistance to alkylating agents. In vitro, the combination of these drugs enhanced the apoptotic and autophagic cell death, as well as suppressed the migratory activities in TMZ-resistant cell lines. Furthermore, in vivo efficacy experiment showed that treatment of combination of VPA and TMZ significantly inhibited tumor growth compared with the monotherapy groups of mice. These results suggest that the clinical efficacy of TMZ chemotherapy in TMZ-resistant malignant glioma may be improved by combination with VPA