168 research outputs found

    The Galactic population of HMXBs as seen with INTEGRAL during its four first years of activity

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    We collected the parameters (position, absorption, spin, orbital period, etc..), when known, of all Galactic sources detected by INTEGRAL during its four first years of activity. We use these parameters to test theoretical predictions. For example, it is clear that HMXBs tend to be found mostly in the tangential direction of the Galactic arms, while LMXBs tend to be clustered in the Galactic bulge. We then focus on HMXBs and present two possible new tools, in addition to the well-known ``Corbet-diagram'', to distinguish between Be-HMXBs and Sg-HMXBsComment: 5 pages, 3 figures proceedings of "A population explosion: the nature and evolution of X-ray binaries in diverse environments", conference held in St.Petersburg Beach, Florida; R.M.Bandyopadhyay, S.Wachter, D.Gelino, C.R.Gelino, ed

    Exposures to Airborne Particulate Matter and Adverse Perinatal Outcomes: A Biologically Plausible Mechanistic Framework for Exploring Potential Effect Modification by Nutrition

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    OBJECTIVES: The specific objectives are threefold: to describe the biologically plausible mechanistic pathways by which exposure to particulate matter (PM) may lead to the adverse perinatal outcomes of low birth weight (LBW), intrauterine growth retardation (IUGR), and preterm delivery (PTD); review the evidence showing that nutrition affects the biologic pathways; and explain the mechanisms by which nutrition may modify the impact of PM exposure on perinatal outcomes. METHODS: We propose an interdisciplinary conceptual framework that brings together maternal and infant nutrition, air pollution exposure assessment, and cardiopulmonary and perinatal epidemiology. Five possible albeit not exclusive biologic mechanisms have been put forth in the emerging environmental sciences literature and provide corollaries for the proposed framework. CONCLUSIONS: Protecting the environmental health of mothers and infants remains a top global priority. The existing literature indicates that the effects of PM on LBW, PTD, and IUGR may manifest through the cardiovascular mechanisms of oxidative stress, inflammation, coagulation, endothelial function, and hemodynamic responses. PM exposure studies relating mechanistic pathways to perinatal outcomes should consider the likelihood that biologic responses and adverse birth outcomes may be derived from both PM and non-PM sources (e.g., nutrition). In the concluding section, we present strategies for empirically testing the proposed model and developing future research efforts

    Defining the Differences Between Episodic Migraine and Chronic Migraine

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    Chronic migraine (CM) and episodic migraine (EM) are part of the spectrum of migraine disorders, but they are distinct clinical entities. Population-based studies have shown that those with CM demonstrate higher individual and societal burden because they are significantly more disabled than those with EM and have greater impaired quality of life both inside and outside the home. Proper diagnosis of both conditions requires clearly defined clinical criteria. Diagnosis enables the initiation of appropriate treatments and risk-factor modification, which ultimately improve functional status and quality of life for persons with migraine. Recognizing that both disorders are on the spectrum of migraine, this review serves as a guide to define the disease state of CM as distinct from EM in terms of clinical, epidemiological, sociodemographic, and comorbidity profiles

    The impact of respiratory infections and probiotic use on the nasal microbiota of frail residents in long-term care homes

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    Background Residents in long-term care (LTC) homes, who tend to be of advanced age and frail, are at increased risk of respiratory infections. The respiratory microbiota is known to change with age, but whether these changes contribute to the risk of infection is not known.Aim Our goal was to determine how the nasal microbiota of frail older adults changes during symptoms of influenza-like illness (ILI) and how this may be impacted by enrollment in a placebo-controlled trial testing the feasibility of administering a Lactobacillus rhamnosus GG probiotic to prevent respiratory infection (2014–2017).Methods The microbiome of the nasal (mid-turbinate) of 150 residents of LTC homes was interrogated using 16S rRNA gene sequencing.Results We identified a diverse and individualized microbiota which could be separated into 9 distinct clusters based on Bray Curtis distances. Samples collected during symptoms of influenza-like illness (ILI) differed statistically from those collected pre- and post-cold and influenza season, and we observed decreased temporal stability – as measured by movement between clusters – in individuals who experienced ILI compared to those who did not.Conclusions The use of probiotics decreased ILI-induced changes to the microbiota; however, it is not clear whether this decrease is sufficient to prevent respiratory illness

    cAMP-Signalling Regulates Gametocyte-Infected Erythrocyte Deformability Required for Malaria Parasite Transmission.

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    Blocking Plasmodium falciparum transmission to mosquitoes has been designated a strategic objective in the global agenda of malaria elimination. Transmission is ensured by gametocyte-infected erythrocytes (GIE) that sequester in the bone marrow and at maturation are released into peripheral blood from where they are taken up during a mosquito blood meal. Release into the blood circulation is accompanied by an increase in GIE deformability that allows them to pass through the spleen. Here, we used a microsphere matrix to mimic splenic filtration and investigated the role of cAMP-signalling in regulating GIE deformability. We demonstrated that mature GIE deformability is dependent on reduced cAMP-signalling and on increased phosphodiesterase expression in stage V gametocytes, and that parasite cAMP-dependent kinase activity contributes to the stiffness of immature gametocytes. Importantly, pharmacological agents that raise cAMP levels in transmissible stage V gametocytes render them less deformable and hence less likely to circulate through the spleen. Therefore, phosphodiesterase inhibitors that raise cAMP levels in P. falciparum infected erythrocytes, such as sildenafil, represent new candidate drugs to block transmission of malaria parasites

    Two novel human cytomegalovirus NK cell evasion functions target MICA for lysosomal degradation

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    NKG2D plays a major role in controlling immune responses through the regulation of natural killer (NK) cells, αÎČ and γΎ T-cell function. This activating receptor recognizes eight distinct ligands (the MHC Class I polypeptide-related sequences (MIC) A andB, and UL16-binding proteins (ULBP)1–6) induced by cellular stress to promote recognition cells perturbed by malignant transformation or microbial infection. Studies into human cytomegalovirus (HCMV) have aided both the identification and characterization of NKG2D ligands (NKG2DLs). HCMV immediate early (IE) gene up regulates NKGDLs, and we now describe the differential activation of ULBP2 and MICA/B by IE1 and IE2 respectively. Despite activation by IE functions, HCMV effectively suppressed cell surface expression of NKGDLs through both the early and late phases of infection. The immune evasion functions UL16, UL142, and microRNA(miR)-UL112 are known to target NKG2DLs. While infection with a UL16 deletion mutant caused the expected increase in MICB and ULBP2 cell surface expression, deletion of UL142 did not have a similar impact on its target, MICA. We therefore performed a systematic screen of the viral genome to search of addition functions that targeted MICA. US18 and US20 were identified as novel NK cell evasion functions capable of acting independently to promote MICA degradation by lysosomal degradation. The most dramatic effect on MICA expression was achieved when US18 and US20 acted in concert. US18 and US20 are the first members of the US12 gene family to have been assigned a function. The US12 family has 10 members encoded sequentially through US12–US21; a genetic arrangement, which is suggestive of an ‘accordion’ expansion of an ancestral gene in response to a selective pressure. This expansion must have be an ancient event as the whole family is conserved across simian cytomegaloviruses from old world monkeys. The evolutionary benefit bestowed by the combinatorial effect of US18 and US20 on MICA may have contributed to sustaining the US12 gene family

    A cohort study: temporal trends in prevalence of antecedents, comorbidities and mortality in Aboriginal and non-Aboriginal Australians with first heart failure hospitalization, 2000-2009

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    Abstract Background/objectives: Little is known about trends in risk factors and mortality for Aboriginal Australians with heart failure (HF). This population-based study evaluated trends in prevalence of risk factors, 30-day and 1-year all-cause mortality following first HF hospitalization among Aboriginal and non-Aboriginal Western Australians in the decade 2000-2009. Methods: Linked-health data were used to identify patients (20-84 years), with a first-ever HF hospitalization. Trends in demographics, comorbidities, interventions and risk factors were evaluated. Logistic and Cox regression models were fitted to test and compare trends over time in 30-day and 1-year mortality. Results: Of 17,379 HF patients, 1,013 (5.8 %) were Aboriginal. Compared with 2000-2002, the prevalence (as history) of myocardial infarction and hypertension increased more markedly in 2006-2009 in Aboriginal (versus non-Aboriginal) patients, while diabetes and chronic kidney disease remained disproportionately higher in Aboriginal patients. Risk factor trends, including the Charlson comorbidity index, increased over time in younger Aboriginal patients. Risk-adjusted 30-day mortality did not change over the decade in either group. Risk-adjusted 1-year mortality (in 30-day survivors) was non-significantly higher in Aboriginal patients in 2006-2008 compared with 2000-2002 (hazard ratio (HR) 1.44; 95 % CI 0.85-2.41; p-trend = 0.47) whereas it decreased in non-Aboriginal patients (HR 0.87; 95 % CI 0.78-0.97; p-trend = 0.01). Conclusions: Between 2000 and 2009, the prevalence of HF antecedents increased and remained disproportionately higher in Aboriginal (versus non-Aboriginal) HF patients. Risk-adjusted 1-year mortality did not improve in Aboriginal patients over the period in contrast with non-Aboriginal patients. These findings highlight the need for better prevention and post-HF care in Aboriginal Australians

    Female reproductive tract infections: understandings and care seeking behaviour among women of reproductive age in Lagos, Nigeria

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    <p>Abstract</p> <p>Background</p> <p>Reproductive tract infections (RTI's) are endemic in developing countries and entail a heavy toll on women. If untreated, RTI's can lead to adverse health outcomes such as infertility, ectopic pregnancy and increased vulnerability to transmission of the human immunodeficiency virus. It is also associated with adverse pregnancy outcomes. While RTI's and its sequelae abound in Nigeria, there is paucity of publications on the subject in the country. This study assessed the understandings and care seeking behavior with regards to RTI's among women of reproductive age in Lagos, Nigeria with the aim of improving awareness on the subject.</p> <p>Methods</p> <p>A descriptive cross sectional survey of women attending the gynaecological outpatient and family planning clinics of the Lagos State University Teaching Hospital was carried out between 1<sup>st </sup>June 2008 and 31<sup>st </sup>August 2008 using a pre-tested questionnaire. Data was analysed using the Epi-Info 3.5 statistical software of the Centre for Disease Control and Prevention, Atlanta U.S.A.</p> <p>Results</p> <p>Most of the respondents (77.2%) had heard of RTI's. Toilet was the most perceived mode of contracting RTI's (44.6%), followed by sexual intercourse and poor hygiene. Vaginal discharge was the commonest symptom of RTI's named while inability to get pregnant was the commonest named complication. Majority of the respondent's demonstrated poor overall knowledge of symptoms and complications of RTI"s. 37.4% of the respondents had experienced symptoms of RTI's in the preceding six months. Vaginal discharge was the commonest symptom reported (21.8%) and the majority of those who reported symptoms sought medical treatment. Government health centres were the most visited health facilities for treatment.</p> <p>Conclusion</p> <p>Even though most of the respondents have heard of RTI's and sought treatment when symptomatic, they demonstrated poor overall understanding of the subject. There is need to educate women on preventive strategies, as RTI's are often assymptomatic.</p
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