371 research outputs found

    Spin Hall Conductance of the Two Dimensional Hole Gas in a Perpendicular Magnetic Field

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    The charge and spin Hall conductance of the two-dimensional hole gas within the Luttinger model with and without inversion symmetry breaking terms in a perpendicular magnetic field are studied, and two key phenomena are predicted. The sign of the spin Hall conductance is modulated periodically by the external magnetic field, which means a possible application in the future. Furthermore, a resonant spin Hall conductance in the two-dimensional hole gas with a certain hole density at a typical magnetic field is indicated, which implies a likely way to firmly establish the intrinsic spin Hall effect. The charge Hall conductance is unaffected by the spin-orbit coupling.Comment: accepted for publication in Phys. Rev. B; 6 pages, 4 figure

    Respiratory Chlamydia Infection Induce Release of Hepoxilin A3 and Histamine Production by Airway Neutrophils

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    Background: Hepoxilins are biologically active metabolites of arachidonic acid that are formed through the 12-lipoxygenase pathway. Hepoxilin A3 is now known to be an important regulator of mucosal inflammation in response to infection by bacterial pathogens and was recently identified as a potent neutrophil chemoattractant in the intestinal mucosa. Our goal in this study was to determine if airway infection with Chlamydia in a murine model of allergic airway disease (AAD) induces hepoxilin secretion along with airway neutrophilia.Methods: We utilized an AAD adult Balb/c mouse model to evaluate airway pathology and immune response by assaying bronchoalveolar lavage (BAL) fluid cytokine, cellularity, histidine decarboxylase (HDC) as well as histamine released in response to in-vivo chlamydial antigen stimulation of purified airway neutrophils. Hepoxilin A3 production was determined by Western blot identification of 12-lipoxygenase precursor (12-LO).Results: Chlamydial infection induced increased production of IL-2, IL-12, TNF-α, and IFN-γ in BAL fluid compared to uninfected animals. Chlamydia-infected mice responded with robust airway neutrophil infiltration and upon induction of AAD increased their production of IL-4, IL-5, and IL-13 by >3 fold compared to unsensitized groups. In addition, 12-LO mRNA was upregulated in infected, but not in uninfected AAD mice, suggesting the production of hepoxilin A3. mRNA expression of HDC was induced only in neutrophils from the airways of Chlamydia-infected mice, but was not seen in AAD only or uninfected controls. When purified neutrophils from infected animals were challenged with chlamydial antigen in vitro there was significant histamine release.Conclusions: Our data confirms the production and release of hepoxilin A3 in the murine airways concomitant with airway neutrophilia in response to chlamydial infection. We further confirmed that Chlamydia provokes the production and release of histamine by these neutrophils. These findings suggest that neutrophils, provoked by Chlamydia infection can synthesize and release histamine, thereby contributing directly to airway inflammation

    Measurement of the critical DNA lesions produced by antibody-directed enzyme prodrug therapy (ADEPT) in vitro, in vivo and in clinical material

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    An antibody-directed enzyme prodrug therapy (ADEPT) system against CEA-positive tumours is currently in phase I clinical trials. It consists of a prodrug, 4-[N,N-bis(2-iodoethyl) amino] phenoxycarbonyl L -glutamic acid (ZD2767P) and a conjugate of the F(ab')2 anti-CEA antibody A5B7 and the bacterial enzyme carboxypeptidase G2 (CPG2). ZD2767P is converted by antibody-targeted CPG2 into an active bifunctional alkylating drug (ZD2767) at the tumour site. The IC 50 value of the prodrug against the human colorectal tumour LS174T cell line was 55 ± 9 μM following a 1 h exposure. In contrast, co-incubation of ZD2767P with CPG2 resulted in 229-fold increase in activity. Using a modified comet assay, DNA interstrand cross links (ISC) were detected within 1 h of ZD2767P + CPG2 treatment and were repaired by 24 h. A clear dose–response was seen between the level of ISC, growth inhibition and ZD2767 concentration. Administration of a therapeutic dose of ZD2767P 72 h after the F(ab′)2 A5B7 conjugate to mice bearing LS147T xenografts resulted in extensive ISC in the tumour after 1 h; repair was seen at 24 h. Tumour biopsies and peripheral lymphocytes were studied in 5 patients on the ADEPT phase I clinical trial. In 4 patients no ISC were detected. These patients also demonstrated poor localization of conjugate and no tumour response was seen. However a significant level of ISC was detected in one tumour biopsy, which also showed evidence of conjugate localization and clinical response. These studies demonstrate the application of the comet assay in the measurement of ISC in vitro and in clinical material and confirm that activation of ZD2767P results in the formation of DNA crosslinks. © 2001 Cancer Research Campaign http://www.bjcancer.co

    A phase I trial of antibody directed enzyme prodrug therapy (ADEPT) in patients with advanced colorectal carcinoma or other CEA producing tumours

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    Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated selectively at the tumour site by an enzyme, which has been targeted to the tumour by an antibody (antibody-enzyme conjugate). Previous clinical trials have shown evidence of tumour response, however, the activated drug had a long half-life, which resulted in dose-limiting myelosuppression. Also, the targeting system, although giving high tumour to blood ratios of antibody-enzyme conjugate (10 000 : 1) required administration of a clearing antibody in addition to the antibody-enzyme conjugate. The purpose of this current study therefore was to attempt tumour targeting of the antibody-enzyme conjugate without the clearing antibody, and to investigate a new prodrug (bis-iodo phenol mustard, ZD2767P) whose activated form is highly potent and has a short half-life. Twenty-seven patients were treated with antibody-directed enzyme prodrug therapy using A5CP antibody-enzyme conjugate and ZD2767P prodrug, in a dose-escalating phase I trial. The maximum tolerated dose of ZD2767P was reached at 15.5 mg m−2×three administrations with a serum carboxypeptidase G2 level of 0.05 U ml−1. Myelosuppression limited dose escalation. Other toxicities were mild. Patients' quality of life was not adversely affected during the trial as assessed by the measures used. There were no clinical or radiological responses seen in the study, but three patients had stable disease at day 56. Human anti-mouse antibody and human anti-carboxypeptidase G2 antibody were produced in response to the antibody enzyme conjugate (A5CP). The antibody-enzyme conjugate localisation data (carboxypeptidase G2 enzyme levels by HPLC on tumour and normal tissue samples, and gamma camera analysis of I-131 radiolabelled conjugate) are consistent with inadequate tumour localisation (median tumour: normal tissue ratios of antibody-enzyme conjugate of less than 1). A clearance system is therefore desirable with this antibody-enzyme conjugate or a more efficient targeting system is required. ZD2767P was shown to clear rapidly from the circulation and activated drug was not measurable in the blood. ZD2767P has potential for use in future antibody-directed enzyme prodrug therapy systems

    Interdisciplinary Approaches to the Medieval Warhorse

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    The warhorse is arguably the most characteristic animal of the English Middle Ages. But while the development and military uses of warhorses have been intensively studied by historians, the archaeological evidence is too often dispersed, overlooked or undervalued. Instead, we argue that to fully understand the cultural significance and functional role of the medieval warhorse, a systematic study of the full range of archaeological evidence for warhorses (and horses more generally) from medieval England is necessary. This requires engagement with material evidence at a wide variety of scales — from individual artefacts through to excavated assemblages and landscape-wide distributions — dating between the late Saxon and Tudor period (c. AD 800–1600). We present here a case study of our interdisciplinary engaged research design focusing upon an important English royal stud site at Odiham in Hampshire. This brings together several fields of study, including (zoo)archaeology, history, landscape survey, and material culture studies to produce new understandings about a beast that was an unmistakable symbol of social status and a decisive weapon on the battlefield

    Nasal sprays and behavioural interventions compared with usual care for acute respiratory illness in primary care: a randomised, controlled, open-label, parallel-group trial.

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    BACKGROUND: A small amount of evidence suggests that nasal sprays, or physical activity and stress management, could shorten the duration of respiratory infections. This study aimed to assess the effect of nasal sprays or a behavioural intervention promoting physical activity and stress management on respiratory illnesses, compared with usual care. METHODS: This randomised, controlled, open-label, parallel-group trial was done at 332 general practitioner practices in the UK. Eligible adults (aged ≥18 years) had at least one comorbidity or risk factor increasing their risk of adverse outcomes due to respiratory illness (eg, immune compromise due to serious illness or medication; heart disease; asthma or lung disease; diabetes; mild hepatic impairment; stroke or severe neurological problem; obesity [BMI ≥30 kg/m2]; or age ≥65 years) or at least three self-reported respiratory tract infections in a normal year (ie, any year before the COVID-19 pandemic). Participants were randomly assigned (1:1:1:1) using a computerised system to: usual care (brief advice about managing illness); gel-based spray (two sprays per nostril at the first sign of an infection or after potential exposure to infection, up to 6 times per day); saline spray (two sprays per nostril at the first sign of an infection or after potential exposure to infection, up to 6 times per day); or a brief behavioural intervention in which participants were given access to a website promoting physical activity and stress management. The study was partially masked: neither investigators nor medical staff were aware of treatment allocation, and investigators who did the statistical analysis were unaware of treatment allocation. The sprays were relabelled to maintain participant masking. Outcomes were assessed using data from participants' completed monthly surveys and a survey at 6 months. The primary outcome was total number of days of illness due to self-reported respiratory tract illnesses (coughs, colds, sore throat, sinus or ear infections, influenza, or COVID-19) in the previous 6 months, assessed in the modified intention-to-treat population, which included all randomly assigned participants who had primary outcome data available. Key secondary outcomes were possible harms, including headache or facial pain, and antibiotic use, assessed in all randomly assigned participants. This trial was registered with ISRCTN, 17936080, and is closed to recruitment. FINDINGS: Between Dec 12, 2020, and April 7, 2023, of 19 475 individuals screened for eligibility, 13 799 participants were randomly assigned to usual care (n=3451), gel-based nasal spray (n=3448), saline nasal spray (n=3450), or the digital intervention promoting physical activity and stress management (n=3450). 11 612 participants had complete data for the primary outcome and were included in the primary outcome analysis (usual care group, n=2983; gel-based spray group, n=2935; saline spray group, n=2967; behavioural website group, n=2727). Compared with participants in the usual care group, who had a mean of 8·2 (SD 16·1) days of illness, the number of days of illness was significantly lower in the gel-based spray group (mean 6·5 days [SD 12·8]; adjusted incidence rate ratio [IRR] 0·82 [99% CI 0·76-0·90]; p<0·0001) and the saline spray group (6·4 days [12·4]; 0·81 [0·74-0·88]; p<0·0001), but not in the group allocated to the behavioural website (7·4 days [14·7]; 0·97 [0·89-1·06]; p=0·46). The most common adverse event was headache or sinus pain in the gel-based group: 123 (4·8%) of 2556 participants in the usual care group; 199 (7·8%) of 2498 participants in the gel-based group (risk ratio 1·61 [95% CI 1·30-1·99]; p<0·0001); 101 (4·5%) of 2377 participants in the saline group (0·81 [0·63-1·05]; p=0·11); and 101 (4·5%) of 2091 participants in the behavioural intervention group (0·95 [0·74-1·22]; p=0·69). Compared with usual care, antibiotic use was lower for all interventions: IRR 0·65 (95% CI 0·50-0·84; p=0·001) for the gel-based spray group; 0·69 (0·45-0·88; p=0·003) for the saline spray group; and 0·74 (0·57-0·94; p=0·02) for the behavioural website group. INTERPRETATION: Advice to use either nasal spray reduced illness duration and both sprays and the behavioural website reduced antibiotic use. Future research should aim to address the impact of the widespread implementation of these simple interventions. FUNDING: National Institute for Health and Care Research

    TLR2, but Not TLR4, Is Required for Effective Host Defence against Chlamydia Respiratory Tract Infection in Early Life

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    Chlamydia pneumoniae commonly causes respiratory tract infections in children, and epidemiological investigations strongly link infection to the pathogenesis of asthma. The immune system in early life is immature and may not respond appropriately to pathogens. Toll-like receptor (TLR)2 and 4 are regarded as the primary pattern recognition receptors that sense bacteria, however their contribution to innate and adaptive immunity in early life remains poorly defined. We investigated the role of TLR2 and 4 in the induction of immune responses to Chlamydia muridarum respiratory infection, in neonatal wild-type (Wt) or TLR2-deficient (−/−), 4−/− or 2/4−/− BALB/c mice. Wt mice had moderate disease and infection. TLR2−/− mice had more severe disease and more intense and prolonged infection compared to other groups. TLR4−/− mice were asymptomatic. TLR2/4−/− mice had severe early disease and persistent infection, which resolved thereafter consistent with the absence of symptoms in TLR4−/− mice. Wt mice mounted robust innate and adaptive responses with an influx of natural killer (NK) cells, neutrophils, myeloid (mDCs) and plasmacytoid (pDCs) dendritic cells, and activated CD4+ and CD8+ T-cells into the lungs. Wt mice also had effective production of interferon (IFN)γ in the lymph nodes and lung, and proliferation of lymph node T-cells. TLR2−/− mice had more intense and persistent innate (particularly neutrophil) and adaptive cell responses and IL-17 expression in the lung, however IFNγ responses and T-cell proliferation were reduced. TLR2/4−/− mice had reduced innate and adaptive responses. Most importantly, neutrophil phagocytosis was impaired in the absence of TLR2. Thus, TLR2 expression, particularly on neutrophils, is required for effective control of Chlamydia respiratory infection in early life. Loss of control of infection leads to enhanced but ineffective TLR4-mediated inflammatory responses that prolong disease symptoms. This indicates that TLR2 agonists may be beneficial in the treatment of early life Chlamydia infections and associated diseases

    Unconscious bias and the medical model: How the social model may hold the key to transformative thinking about disability discrimination

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    This article seeks to gain access to a new way to engage with disability discrimination and the legal approaches to it by focusing on the two central models: the medical and social models. It discusses how the law has based the definition of disability on the medical model and suggests that this may strengthen some of the underlying factors that contribute to segregation and discrimination of disabled people. This article argues that the law should now switch focus to the social model, in an attempt to transform people’s attitudes towards disabled people and become a positive force to reduce discrimination. It makes reference to the reasonable adjustment duty contained in sections 20 and 21 Equality Act 2010, the Framework Directive and by way of comparison the American with Disabilities Act 1990. Relevant critical theories are integrated as a means to explore the conception and the hierarchy that exist between able-bodied individuals and disabled individuals

    The Role of Individual Variables, Organizational Variables and Moral Intensity Dimensions in Libyan Management Accountants’ Ethical Decision Making

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    This study investigates the association of a broad set of variables with the ethical decision making of management accountants in Libya. Adopting a cross-sectional methodology, a questionnaire including four different ethical scenarios was used to gather data from 229 participants. For each scenario, ethical decision making was examined in terms of the recognition, judgment and intention stages of Rest’s model. A significant relationship was found between ethical recognition and ethical judgment and also between ethical judgment and ethical intention, but ethical recognition did not significantly predict ethical intention—thus providing support for Rest’s model. Organizational variables, age and educational level yielded few significant results. The lack of significance for codes of ethics might reflect their relative lack of development in Libya, in which case Libyan companies should pay attention to their content and how they are supported, especially in the light of the under-development of the accounting profession in Libya. Few significant results were also found for gender, but where they were found, males showed more ethical characteristics than females. This unusual result reinforces the dangers of gender stereotyping in business. Personal moral philosophy and moral intensity dimensions were generally found to be significant predictors of the three stages of ethical decision making studied. One implication of this is to give more attention to ethics in accounting education, making the connections between accounting practice and (in Libya) Islam. Overall, this study not only adds to the available empirical evidence on factors affecting ethical decision making, notably examining three stages of Rest’s model, but also offers rare insights into the ethical views of practising management accountants and provides a benchmark for future studies of ethical decision making in Muslim majority countries and other parts of the developing world

    Knockdown of MBP-1 in Human Foreskin Fibroblasts Induces p53-p21 Dependent Senescence

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    MBP-1 acts as a general transcriptional repressor. Overexpression of MBP-1 induces cell death in a number of cancer cells and regresses tumor growth. However, the function of endogenous MBP-1 in normal cell growth regulation remains unknown. To unravel the role of endogenous MBP-1, we knocked down MBP-1 expression in primary human foreskin fibroblasts (HFF) by RNA interference. Knockdown of MBP-1 in HFF (HFF-MBPsi-4) resulted in an induction of premature senescence, displayed flattened cell morphology, and increased senescence-associated beta-galactosidase activity. FACS analysis of HFF-MBPsi-4 revealed accumulation of a high number of cells in the G1-phase. A significant upregulation of cyclin D1 and reduction of cyclin A was detected in HFF-MBPsi-4 as compared to control HFF. Senescent fibroblasts exhibited enhanced expression of phosphorylated and acetylated p53, and cyclin-dependent kinase inhibitor, p21. Further analysis suggested that promyolocytic leukemia protein (PML) bodies are dramatically increased in HFF-MBPsi-4. Together, these results demonstrated that knockdown of endogenous MBP-1 is involved in cellular senescence of HFF through p53-p21 pathway
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