Down-Regulation of Platelet Surface CD47 Expression in Escherichia coli O157:H7 Infection-Induced Thrombocytopenia

BACKGROUND: Platelet depletion is a key feature of hemolytic uremic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC) infection. The mechanism underlying STEC-induced platelet depletion, however, is not completely understood. METHODOLOGY/PRINCIPAL FINDINGS: Here we demonstrated for the first time that platelet surface expression of CD47 was significantly decreased in C57BL6 mice treated with concentrated culture filtrates (CCF) from STEC O157:H7. STEC O157:H7 CCF treatment also led to a sharp drop of platelet counts. The reduction of cell surface CD47 was specific for platelets but not for neutrophil, monocytes and red blood cells. Down-regulation of platelet surface CD47 was also observed in isolated human platelets treated with O157:H7 CCF. Platelet surface CD47 reduction by O157:H7 CCF could be blocked by anti-TLR4 antibody but not anti-CD62 antibody. Down-regulation of platelet surface CD47 was positively correlated with platelet activation and phagocytosis by human monocyte-derived macrophages. Furthermore, the enhanced phagocytosis process of O157:H7 CCF-treated platelets was abolished by addition of soluble CD47 recombinants. CONCLUSIONS/SIGNIFICANCE: Our results suggest that platelet CD47 down-regulation may be a novel mechanism underneath STEC-induced platelet depletion, and that the interactions between CD47 and its receptor, signal regulatory protein alpha (SIRPalpha), play an essential role in modulating platelet homeostasis

Risk factors for high-altitude headache upon acute high-altitude exposure at 3700 m in young Chinese men: a cohort study.

BackgroundThis prospective and observational study aimed to identify demographic, physiological and psychological risk factors associated with high-altitude headache (HAH) upon acute high-altitude exposure.MethodsEight hundred fifty subjects ascended by plane to 3700 m above Chengdu (500 m) over a period of two hours. Structured Case Report Form (CRF) questionnaires were used to record demographic information, physiological examinations, psychological scale, and symptoms including headache and insomnia a week before ascending and within 24 hours after arrival at 3700 m. Binary logistic regression models were used to analyze the risk factors for HAH.ResultsThe incidence of HAH was 73.3%. Age (p =0.011), physical labor intensity (PLI) (p =0.044), primary headache history (p <0.001), insomnia (p <0.001), arterial oxygen saturation (SaO2) (p =0.001), heart rate (HR) (p =0.002), the Self-Rating Anxiety Scale (SAS) (p <0.001), and the Epworth Sleepiness Scale (ESS) (p <0.001) were significantly different between HAH and non-HAH groups. Logistic regression models identified primary headache history, insomnia, low SaO2, high HR and SAS as independent risk factors for HAH.ConclusionsInsomnia, primary headache history, low SaO2, high HR, and high SAS score are the risk factors for HAH. Our findings will provide novel avenues for the study, prevention and treatment of HAH

Defense against Adversarial Cloud Attack on Remote Sensing Salient Object Detection

Detecting the salient objects in a remote sensing image has wide applications for the interdisciplinary research. Many existing deep learning methods have been proposed for Salient Object Detection (SOD) in remote sensing images and get remarkable results. However, the recent adversarial attack examples, generated by changing a few pixel values on the original remote sensing image, could result in a collapse for the well-trained deep learning based SOD model. Different with existing methods adding perturbation to original images, we propose to jointly tune adversarial exposure and additive perturbation for attack and constrain image close to cloudy image as Adversarial Cloud. Cloud is natural and common in remote sensing images, however, camouflaging cloud based adversarial attack and defense for remote sensing images are not well studied before. Furthermore, we design DefenseNet as a learn-able pre-processing to the adversarial cloudy images so as to preserve the performance of the deep learning based remote sensing SOD model, without tuning the already deployed deep SOD model. By considering both regular and generalized adversarial examples, the proposed DefenseNet can defend the proposed Adversarial Cloud in white-box setting and other attack methods in black-box setting. Experimental results on a synthesized benchmark from the public remote sensing SOD dataset (EORSSD) show the promising defense against adversarial cloud attacks

Impacts of recent cultivation on genetic diversity pattern of a medicinal plant, Scutellaria baicalensis (Lamiaceae)

<p>Abstract</p> <p>Background</p> <p>Cultivation of medicinal plants is not only a means for meeting current and future demands for large volume production of plant-based drug and herbal remedies, but also a means of relieving harvest pressure on wild populations. <it>Scutellaria baicalensis </it>Georgi (Huang-qin or Chinese skullcap) is a very important medicinal plant in China. Over the past several decades, wild resource of this species has suffered rapid declines and large-scale cultivation was initiated to meet the increasing demand for its root. However, the genetic impacts of recent cultivation on <it>S. baicalensis </it>have never been evaluated. In this study, the genetic diversity and genetic structure of 28 wild and 22 cultivated populations were estimated using three polymorphic chloroplast fragments. The objectives of this study are to provide baseline data for preserving genetic resource of <it>S. baicalensis </it>and to evaluate the genetic impacts of recent cultivation on medicinal plants, which may be instructive to future cultivation projects of traditional Chinese medicinal plants.</p> <p>Results</p> <p>Thirty-two haplotypes of <it>S. baicalensis </it>(HapA-Y and Hap1-7) were identified when three chloroplast spacers were combined. These haplotypes constituted a shallow gene tree without obvious clusters for cultivated populations, suggesting multiple origins of cultivated <it>S. baicalensis</it>. Cultivated populations (<it>h</it>_T= 0.832) maintained comparable genetic variation with wild populations (<it>h</it>_T= 0.888), indicating a slight genetic bottleneck due to multiple origins of cultivation. However, a substantial amount of rare alleles (10 out of 25 haplotypes within wild populations) lost during the course of <it>S. baicalensis </it>cultivation. The genetic differentiation for cultivated group (<it>G</it>_ST= 0.220) was significantly lower than that of wild group (<it>G</it>_ST= 0.701). Isolation by distance analysis showed that the effect of geographical isolation on genetic structure was significant in wild populations (<it>r </it>= 0.4346, <it>P </it>< 0.0010), but not in cultivated populations (<it>r = </it>0.0599, <it>P </it>= 0.2710). These genetic distribution patterns suggest that a transient cultivation history and the extensive seed change among different geographical areas during the course of <it>S. baicalensis </it>cultivation.</p> <p>Conclusions</p> <p>Although cultivated <it>S. baicalensis </it>maintains comparable genetic diversity relative to wild populations, recent cultivation has still imposed profound impacts on genetic diversity patterns of the cultivated <it>S. baicalensis </it>populations, i.e., the loss of rare alleles and homogenization of cultivated populations. This study suggests that conservation-by-cultivation is an effective means for protecting genetic resources of <it>S. baicalensis</it>, however, the wild resources still need to be protected <it>in situ </it>and the evolutionary consequences of extensive seed exchange mediated by human being should be monitored carefully.</p

1α,6β,7β,11α,15β-Penta­hydr­oxy-7α,20-ep­oxy-ent-kaur-16-ene

The title compound, C20H30O6, a natural ent-kaurane diterpenoid, named nervosanin B, was obtained from the medicinal plant Isodon serra. It is composed of four rings with the expected trans and cis junctions. One of the six-membered rings is in a chair conformation, the other two are in boat conformations and the five-membered ring adopts an evenlope conformation. The mol­ecules stack along the a axis and are linked together by inter­molecular O—H⋯O hydrogen bonds. Two intramolecular O—H⋯O interactions also occur