1,369 research outputs found

    IL-1RI (interleukin-1 receptor type I) signalling is essential for host defence and hemichannel activity during acute central nervous system bacterial infection

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    Staphylococcus aureus is a common aetiological agent of bacterial brain abscesses. We have previously established that a considerable IL-1 (interleukin-1) response is elicited immediately following S. aureus infection, where the cytokine can exert pleiotropic effects on glial activation and blood–brain barrier permeability. To assess the combined actions of IL-1α and IL-1β during CNS (central nervous system) infection, host defence responses were evaluated in IL-1RI (IL-1 receptor type I) KO (knockout) animals. IL-1RI KO mice were exquisitely sensitive to intracerebral S. aureus infection, as demonstrated by enhanced mortality rates and bacterial burdens within the first 24 h following pathogen exposure compared with WT (wild-type) animals. Loss of IL-1RI signalling also dampened the expression of select cytokines and chemokines, concomitant with significant reductions in neutrophil and macrophage infiltrates into the brain. In addition, the opening of astrocyte hemichannels during acute infection was shown to be dependent on IL-1RI activity. Collectively, these results demonstrate that IL-1RI signalling plays a pivotal role in the genesis of immune responses during the acute stage of brain abscess development through S. aureus containment, inflammatory mediator production, peripheral immune cell recruitment, and regulation of astrocyte hemichannel activity. Taken in the context of previous studies with MyD88 (myeloid differentiation primary response gene 88) and TLR2 (Toll-like receptor 2) KO animals, the current report advances our understanding of MyD88-dependent cascades and implicates IL-1RI signalling as a major antimicrobial effector pathway during acute brain-abscess formation

    Explosion risk assessment model for underground mine atmosphere

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    In the coal mining industry, explosions or mine fires present the most hazardous safety threats for coal miners or mine rescue members. Hence, the determination of the mine atmosphere explosibility and its evolution are critical for the success of mine rescues or controlling the severity of a mine accident. However, although there are numbers of methods which can be used to identify the explosibility, none of them could well indicate the change to the explosion risk time evolution. The reason is that the underground sealed atmospheric compositions are so complicated and their dynamical changes are also affected by various influence factors. There is no one method that could well handle all such considerations. Therefore, accurately knowing the mine atmospheric status is still a complicated problem for mining engineers. Method of analyzing the explosion safety margin for an underground sealed atmosphere is urgently desired. This article is going to propose a series of theoretical explosion risk assessment models to fully analyze the evolution of explosion risk in an underground mine atmosphere. Models are based on characteristics of the Coward explosibility diagram with combining mathematical analyzing approaches to address following problems: (1) for an "not-explosive" atmosphere, judging the evolution of explosion risk and estimating the change-of-state time span from "not-explosive" to "explosive" and (2) for an "explosive" atmosphere, estimating the "critical" time span of moving out of explosive zone and stating the best risk mitigation strategy. Such research efforts could not only help mine operators understand the explosibility risk of a sealed mine atmosphere but also provide a useful tool to wisely control explosive atmosphere away from any dangers. In order to demonstrate research findings, case studies for derived models are shown and are also used to instruct readers how to apply them. The results provide useful information for effectively controlling an explosive underground sealed atmosphere

    Inhaled nitric oxide alleviates hyperoxia suppressed phosphatidylcholine synthesis in endotoxin-induced injury in mature rat lungs

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    BACKGROUND: We investigated efficacy of inhaled nitric oxide (NO) in modulation of metabolism of phosphatidylcholine (PC) of pulmonary surfactant and in anti-inflammatory mechanism of mature lungs with inflammatory injury. METHODS: Healthy adult rats were divided into a group of lung inflammation induced by i.v. lipopolysaccharides (LPS) or a normal control (C) for 24 h, and then exposed to: room air (Air), 95% oxygen (O), NO (20 parts per million, NO), both O and NO (ONO) as subgroups, whereas [(3)H]-choline was injected i.v. for incorporation into PC of the lungs which were processed subsequently at 10 min, 4, 8, 12 and 24 h, respectively, for measurement of PC synthesis and proinflammatory cytokine production. RESULTS: LPS-NO subgroup had the lowest level of labeled PC in total phospholipids and disaturated PC in bronchoalveolar lavage fluid and lung tissue (decreased by 46–59%), along with the lowest activity of cytidine triphosphate: phosphocholine cytidylyltransferase (-14–18%) in the lungs, compared to all other subgroups at 4 h (p < 0.01), but not at 8 and 12 h. After 24-h, all LPS-subgroups had lower labeled PC than the corresponding C-subgroups (p < 0.05). LPS-ONO had higher labeled PC in total phospholipids and disaturated PC, activity of cytidylyltransferase, and lower activity of nuclear transcription factor-κB and expression of proinflammatory cytokine mRNA, than that in the LPS-O subgroup (p < 0.05). CONCLUSION: In LPS-induced lung inflammation in association with hyperoxia, depressed PC synthesis and enhanced proinflammatory cytokine production may be alleviated by iNO. NO alone only transiently suppressed the PC synthesis as a result of lower activity of cytidylyltransferase

    The Feasibility and Impact of Delivering a Mind-Body Intervention in a Virtual World

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    Introduction: Mind-body medical approaches may ameliorate chronic disease. Stress reduction is particularly helpful, but face-to-face delivery systems cannot reach all those who might benefit. An online, 3-dimensional virtual world may be able to support the rich interpersonal interactions required of this approach. In this pilot study, we explore the feasibility of translating a face-to-face stress reduction program into an online virtual setting and estimate the effect size of the intervention. Methods and Findings: Domain experts in virtual world technology joined with mind body practitioners to translate an existing 8 week relaxation response-based resiliency program into an 8-week virtual world-based program in Second Life™ (SL). Twenty-four healthy volunteers with at least one month's experience in SL completed the program. Each subject filled out the Perceived Stress Scale (PSS) and the Symptom Checklist 90- Revised (SCL-90-R) before and after taking part. Participants took part in one of 3 groups of about 10 subjects. The participants found the program to be helpful and enjoyable. Many reported that the virtual environment was an excellent substitute for the preferred face-to-face approach. On quantitative measures, there was a general trend toward decreased perceived stress, (15.7 to 15.0), symptoms of depression, (57.6 to 57.0) and anxiety (56.8 to 54.8). There was a significant decrease of 2.8 points on the SCL-90-R Global Severity Index (p<0.05). Conclusions: This pilot project showed that it is feasible to deliver a typical mind-body medical intervention through a virtual environment and that it is well received. Moreover, the small reduction in psychological distress suggests further research is warranted. Based on the data collected for this project, a randomized trial with less than 50 subjects would be appropriately powered if perceived stress is the primary outcome

    Longer fixation duration while viewing face images

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    The spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity. We recorded monkeys’ saccadic eye movements as they freely viewed monkey face and natural scene images. The face and natural scene images attracted similar number of fixations, but viewing of faces was accompanied by longer fixations compared with natural scenes. These longer fixations were dependent on the context of facial features. The duration of fixations directed at facial contours decreased when the face images were scrambled, and increased at the later stage of normal face viewing. The results suggest that face and natural scene images can generate different patterns of visuomotor activity. The extra fixation duration on faces may be correlated with the detailed analysis of facial features

    Guillain-Barre syndrome presenting with sensory disturbance following a herpes virus infection: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>We present a case of an unusual clinical manifestation of Guillain-Barre syndrome following a pre-existing herpes virus infection. Although there have been several reports describing the co-existence of herpes virus infection and Guillain-Barre syndrome, we undertook a more in-depth study of the cross-reactivity between herpes viruses and recommend a follow-up study based on serology tests.</p> <p>Case presentation</p> <p>A 39-year-old healthy Caucasian man with Guillain-Barre syndrome presented to our facility initially with sensory disturbance, followed by an atypical descending pattern of clinical progression. On physical examination, our patient showed hot and cold temperature sensory disturbance under the T4 vertebrae level, symmetrically diminished muscle power mainly to his lower limbs, blurred vision, a loss of taste and paresis and diminished reflexes of his lower limbs. Serology test results for common viruses on hospital admission were positive for cytomegalovirus immunoglobulin M, cytomegalovirus immunoglobulin G, herpes simplex virus immunoglobulin M, herpes simplex virus immunoglobulin G, Epstein-Barr virus immunoglobulin M, and varicella zoster virus immunoglobulin G, borderline for Epstein-Barr virus immunoglobulin G and negative for varicella zoster virus immunoglobulin M. At one month after hospital admission his test results were positive for cytomegalovirus immunoglobulin M, cytomegalovirus immunoglobulin G, herpes simplex virus immunoglobulin G, Epstein-Barr virus immunoglobulin G, varicella zoster virus immunoglobulin G, borderline for herpes simplex virus immunoglobulin M and negative for Epstein-Barr virus immunoglobulin M and varicella zoster virus immunoglobulin M. At his six month follow-up, tests were positive for cytomegalovirus immunoglobulin G, herpes simplex virus immunoglobulin M, herpes simplex virus immunoglobulin G, Epstein-Barr virus immunoglobulin G and varicella zoster virus immunoglobulin G and negative for cytomegalovirus immunoglobulin M, Epstein-Barr virus immunoglobulin M and varicella zoster virus immunoglobulin M.</p> <p>Conclusions</p> <p>The clinical manifestation of Guillain-Barre syndrome in our patient followed a combined herpes virus infection. The cross-reactivity between these human herpes viruses may have a pathogenic as well as evolutionary significance. Our patient showed seroconversion at an early stage of Epstein-Barr virus immunoglobulin M to immunoglobulin G antibodies, suggesting that Epstein-Barr virus might have been the cause of this syndrome. Even if this case is not the first of its kind to be reported, it may contribute to a better understanding of the disease and the cross-reaction mechanisms of herpes virus infections. This case report may have a broader clinical impact across more than one area of medicine, suggesting that cooperation between different specialties is always in the patient's best interest.</p

    Regression and stabilization of advanced murine atherosclerotic lesions: a comparison of LDL lowering and HDL raising gene transfer strategies

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    Both reductions in atherogenic lipoproteins and increases in high-density lipoprotein (HDL) levels may affect atherosclerosis regression. Here, the relative potential of low-density lipoprotein (LDL) lowering and HDL raising gene transfer strategies to induce regression of complex murine atherosclerotic lesions was directly compared. Male C57BL/6 LDL receptor (LDLr)−/− mice were fed an atherogenic diet (1.25% cholesterol and 10% coconut oil) to induce advanced atherosclerotic lesions. A baseline group was killed after 6 months and remaining mice were randomized into a control progression (Adnull or saline), an apolipoprotein (apo) A-I (AdA-I), an LDLr (AdLDLr), or a combined apo A-I/LDLr (AdA-I/AdLDLr) adenoviral gene transfer group and followed-up for another 12 weeks with continuation of the atherogenic diet. Gene transfer with AdLDLr decreased non-HDL cholesterol levels persistently by 95% (p < 0.001) compared with baseline. This drastic reduction of non-HDL cholesterol levels induced lesion regression by 28% (p < 0.001) in the aortic root and by 25% (p < 0.05) in the brachiocephalic artery at 12 weeks after transfer. Change in lesion size was accompanied by enhanced plaque stability, as evidenced by increased collagen content, reduced lesional macrophage content, a drastic reduction of necrotic core area, and decreased expression of inflammatory genes. Elevated HDL cholesterol following AdA-I transfer increased collagen content in lesions, but did not induce regression. Apo A-I gene transfer on top of AdLDLr transfer resulted in additive effects, particularly on inflammatory gene expression. In conclusion, drastic lipid lowering induced by a powerful gene transfer strategy leads to pronounced regression and stabilization of advanced murine atherosclerosis

    Luminescence Dating in Fluvial Settings: Overcoming the Challenge of Partial Bleaching

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    Optically stimulated luminescence (OSL) dating is a versatile technique that utilises the two most ubiquitous minerals on Earth (quartz or K-feldspar) for constraining the timing of sediment deposition. It has provided accurate ages in agreement with independent age control in many fluvial settings, but is often characterised by partial bleaching of individual grains. Partial bleaching can occur where sunlight exposure is limited and so only a portion of the grains in the sample was exposed to sunlight prior to burial, especially in sediment-laden, turbulent or deep water columns. OSL analysis on multiple grains can provide accurate ages for partially bleached sediments where the OSL signal intensity is dominated by a single brighter grain, but will overestimate the age where the OSL signal intensity is equally as bright (often typical of K-feldspar) or as dim (sometimes typical of quartz). In such settings, it is important to identify partial bleaching and the minimum dose population, preferably by analysing single grains, and applying the appropriate statistical age model to the dose population obtained for each sample. To determine accurate OSL ages using these age models, it is important to quantify the amount of scatter (or overdispersion) in the well-bleached part of the partially bleached dose distribution, which can vary between sediment samples depending upon the bedrock sources and transport histories of grains. Here, we discuss how the effects of partial bleaching can be easily identified and overcome to determine accurate ages. This discussion will therefore focus entirely on the burial dose determination for OSL dating, rather than the dose-rate, as only the burial doses are impacted by the effects of partial bleaching

    Anti-plasmodial polyvalent interactions in Artemisia annua L. aqueous extract – possible synergistic and resistance mechanisms

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    Artemisia annua hot water infusion (tea) has been used in in vitro experiments against P. falciparum malaria parasites to test potency relative to equivalent pure artemisinin. High performance liquid chromatography (HPLC) and mass spectrometric analyses were employed to determine the metabolite profile of tea including the concentrations of artemisinin (47.5±0.8 mg L-1), dihydroartemisinic acid (70.0±0.3 mg L-1), arteannuin B (1.3±0.0 mg L-1), isovitexin (105.0±7.2 mg L-1) and a range of polyphenolic acids. The tea extract, purified compounds from the extract, and the combination of artemisinin with the purified compounds were tested against chloroquine sensitive and chloroquine resistant strains of P. falciparum using the DNA-intercalative SYBR Green I assay. The results of these in vitro tests and of isobologram analyses of combination effects showed mild to strong antagonistic interactions between artemisinin and the compounds (9-epi-artemisinin and artemisitene) extracted from A. annua with significant (IC50 <1 μM) anti-plasmodial activities for the combination range evaluated. Mono-caffeoylquinic acids, tri-caffeoylquinic acid, artemisinic acid and arteannuin B showed additive interaction while rosmarinic acid showed synergistic interaction with artemisinin in the chloroquine sensitive strain at a combination ratio of 1:3 (artemisinin to purified compound). In the chloroquine resistant parasite, using the same ratio, these compounds strongly antagonised artemisinin anti-plasmodial activity with the exception of arteannuin B, which was synergistic. This result would suggest a mechanism targeting parasite resistance defenses for arteannuin B’s potentiation of artemisinin

    Reassessment of CXCR4 Chemokine Receptor Expression in Human Normal and Neoplastic Tissues Using the Novel Rabbit Monoclonal Antibody UMB-2

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    BACKGROUND: The CXCR4 chemokine receptor regulates migration and homing of cancer cells to specific metastatic sites. Determination of the CXCR4 receptor status will provide predictive information for disease prognosis and possible therapeutic intervention. However, previous attempts to localize CXCR4 using poorly characterized mouse monoclonal or rabbit polyclonal antibodies have produced predominant nuclear and occasional cytoplasmic staining but did not result in the identification of bona fide cell surface receptors. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we extensively characterized the novel rabbit monoclonal anti-CXCR4 antibody (clone UMB-2) using transfected cells and tissues from CXCR4-deficient mice. Specificity of UMB-2 was demonstrated by cell surface staining of CXCR4-transfected cells; translocation of CXCR4 immunostaining after agonist exposure; detection of a broad band migrating at M(r) 38,000-43,000 in Western blots of homogenates from CXCR4-expressing cells; selective detection of the receptor in tissues from CXCR4+/+ but not from CXCR4-/- mice; and abolition of tissue immunostaining by preadsorption of UMB-2 with its immunizing peptide. In formalin-fixed, paraffin-embedded human tumor tissues, UMB-2 yielded highly effective plasma membrane staining of a subpopulation of tumor cells, which were often heterogeneously distributed throughout the tumor. A comparative analysis of the mouse monoclonal antibody 12G5 and other frequently used commercially available antibodies revealed that none of these was able to detect CXCR4 under otherwise identical conditions. CONCLUSIONS/SIGNIFICANCE: Thus, the rabbit monoclonal antibody UMB-2 may prove of great value in the assessment of the CXCR4 receptor status in a variety of human tumors during routine histopathological examination
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