85 research outputs found

    Lithospheric structure beneath the Zagros collision zone resolved by non-linear teleseismic tomography

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    The upper-mantle structure across the Zagros collision zone, in southwest Iran, is investigated using a non-linear weighted damped least-squares teleseismic tomography approach. The resolution of the structures/transitions in the upper mantle is enhanced significantly by correcting the teleseismic relative arrival time residuals for an a priori crustal velocity model and then performing the inversion with fixed crustal blocks. To investigate whether or not the lithospheric blocks and major transitions in the resulting model are required by the data or are artefacts of the inversion, the data were inverted using two different inverse methods (singular value decomposition and a quadratic programming method). New high-quality seismic velocity models show apparent correlation between surface geological features and seismic velocity structures at lithospheric depth across the Zagros collision zone. The image shows a sharp lithospheric boundary at the Main Zagros Thrust between 100 km and 250 km depth with P-wave velocity about 3 per cent faster within the Arabian Shield to the south. A step-like increase in lithospheric thickness across the Zagros collision zone is assumed to separate two different mantle structures namely the Arabian (to the south) and the Eurasian (to the north) domains. The most striking feature resolved is a north-dipping slab-like positive velocity anomaly

    Correlation of sacral ratio and urinary tract infection in children

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    Introduction: The sacral bone anomalies have an important effect on urinary and gastrointestinal tract and sacral ratio was defined as an indicator for estimating the anorectal abnormalities in children. This study was carried out for determining the association between sacral ratio and Urinary Tract Infections (UTI) among children. Material and Methods: In a cross sectional study, 100 children under 15 years with proven febrile UTI were referred to a referral children center considering the presence and grading of VUR according to VCUG enrolled in this study. Sacral ratio was measured for all cases and the data were compared by student T test, Chi 2 and Mann Whitney tests. SPSS 16.0 software was used for data analysis. P values less than 0.05 were considered significant. Results: 41 boys and 59 girls with mean age 4.8 years were enrolled in this study. The average range of sacral ratio was 0.82. There was no staistical difference between two different genders and ages (p > 0.05). The values of SR in patients with VUR were lower than patients without VUR(P�0.05) but there was no statistically significant difference between both bilateral and unilateral VUR and SR (p > 0.05). Conclusion: The risk of sacral bone abnormality in patients with VUR is more than patients without VUR. Therefore, in patients with UTI and low SR simultaneously, tighter evaluation for VUR and treatment should be considered. © 2018 Kandarini et al

    MicroRNA-21 dysregulates the expression of MEF2C in neurons in monkey and human SIV/HIV neurological disease

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    MicroRNAs (miRNAs) have important roles in regulating a plethora of physiological and pathophysiogical processes including neurodegeneration. In both human immunodeficiency virus (HIV)-associated dementia in humans and its monkey model simian immunodeficiency virus encephalitis (SIVE), we find miR-21, a miRNA largely known for its link to oncogenesis, to be significantly upregulated in the brain. In situ hybridization of the diseased brain sections revealed induction of miR-21 in neurons. miR-21 can be induced in neurons by prolonged N-methyl--aspartic acid receptor stimulation, an excitotoxic process active in HIV and other neurodegenerative diseases. Introduction of miR-21 into human neurons leads to pathological functional defects. Furthermore, we show that miR-21 specifically targets the mRNA of myocyte enhancer factor 2C (MEF2C), a transcription factor crucial for neuronal function, and reduces its expression. MEF2C is dramatically downregulated in neurons of HIV-associated dementia patients, as well as monkeys with SIVE. Together, this study elucidates a novel role for miR-21 in the brain, not only as a potential signature of neurological disease, but also as a crucial effector of HIV-induced neuronal dysfunction and neurodegeneration

    Comparative Expression Profile of miRNA and mRNA in Primary Peripheral Blood Mononuclear Cells Infected with Human Immunodeficiency Virus (HIV-1)

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    Host cells respond to exogenous infectious agents such as viruses, including HIV-1. Studies have evaluated the changes associated with virus infection at the transcriptional and translational levels of the cellular genes involved in specific pathways. While this approach is useful, in our view it provides only a partial view of genome-wide changes. Recently, technological advances in the expression profiling at the microRNA (miRNA) and mRNA levels have made it possible to evaluate the changes in the components of multiple pathways. To understand the role of miRNA and its interplay with host cellular gene expression (mRNA) during HIV-1 infection, we performed a comparative global miRNA and mRNA microarray using human PBMCs infected with HIV-1. The PBMCs were derived from multiple donors and were infected with virus generated from the molecular clone pNL4-3. The results showed that HIV-1 infection led to altered regulation of 21 miRNAs and 444 mRNA more than 2-fold, with a statistical significance of p<0.05. Furthermore, the differentially regulated miRNA and mRNA were shown to be associated with host cellular pathways involved in cell cycle/proliferation, apoptosis, T-cell signaling, and immune activation. We also observed a number of inverse correlations of miRNA and mRNA expression in infected PBMCs, further confirming the interrelationship between miRNA and mRNA regulation during HIV-1 infection. These results for the first time provide evidence that the miRNA profile could be an early indicator of host cellular dysfunction induced by HIV-1

    Blood-based biomarkers for Alzheimer disease: mapping the road to the clinic.

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    Biomarker discovery and development for clinical research, diagnostics and therapy monitoring in clinical trials have advanced rapidly in key areas of medicine - most notably, oncology and cardiovascular diseases - allowing rapid early detection and supporting the evolution of biomarker-guided, precision-medicine-based targeted therapies. In Alzheimer disease (AD), breakthroughs in biomarker identification and validation include cerebrospinal fluid and PET markers of amyloid-β and tau proteins, which are highly accurate in detecting the presence of AD-associated pathophysiological and neuropathological changes. However, the high cost, insufficient accessibility and/or invasiveness of these assays limit their use as viable first-line tools for detecting patterns of pathophysiology. Therefore, a multistage, tiered approach is needed, prioritizing development of an initial screen to exclude from these tests the high numbers of people with cognitive deficits who do not demonstrate evidence of underlying AD pathophysiology. This Review summarizes the efforts of an international working group that aimed to survey the current landscape of blood-based AD biomarkers and outlines operational steps for an effective academic-industry co-development pathway from identification and assay development to validation for clinical use.I recieved an honorarium from Roche Diagnostics for my participation in the advisory panel meeting leading to this pape

    The Impact of South-South Trade Agreements on FDI

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    The integration of emerging markets into the global economy is heavily promoted by foreign direct investment (FDI) inflows. Within the factors driving the location of FDI, regional trade agreements (RTAs) become increasingly relevant for emerging markets. We explore the impact of South-South trade agreements on FDI by dynamic panel models. The MENA countries are compared to the better performing regions in Latin America and Southeast Asia. Several striking results emerge from the analysis. First, agglomeration effects are weaker for the MENA region. Second, the impact of the RTA is important. However, RTAs do not generally rise the attractiveness of the region for foreign investors, as the effect interacts with business-friendly regulations. Third, financial deepening in the host country is a crucial factor, often again in combination with the institutional framework. Furthermore, institutional conditions may not be relevant per se, but only in terms of its interaction with the macroeconomic determinants

    Host Genetic Factors Predisposing to HIV-Associated Neurocognitive Disorder

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    Serum pneumolysin antibody and urinary pneumococcal antigens (binax) level in children with upper respiratory tract infection versus normal controls

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    Background: Streptococcus pneumoniae is a common cause of respiratory infection. Pneumococcal upper respiratory tract infection (URTI) in children is seldom bacteremic. Determination the prevalence of S.pneumoniae infections in children with URTI using rapid urinary antigen test (BINAX now) and titration of serum pneumolysin antibody (added to conventional culture) was the object of this study. Methods: A cross sectional, case-control study done in ENT & pediatric departments of Rasoul Hospital in Tehran, Iran, (2008 -2010) upon 133 cases with upper respiratory tract infection (otitis media, sinusitis and tracheitis). The nosocomial infection omitted in first step. 60 remaining cases followed for S.pneumoniae infection by culture and rapid urinary antigen test (Binax Now). Serum pneumolysin antibody titers compared between 45 cases and 66 controls. Results: Positive culture (S.pneumoniae, H.influenza) obtained in 4/60 URTI cases. Positive urinary S.pneumoniae antigen detected in 50 (30/60) of cases and 6 (4/66) of controls (p=0.01). The pneumolysin antibody level with cut-off level 525pg/ml was higher in URTI cases than controls (982±441 Vs. 525±42, p<0.0001). Area under the ROC curve for pneumolysin antibody was 0.923 (95CI 0.86-0.97, p<0.0001) and had 87 sensitivity and 82 specificity for differentiation between cases and controls. Conclusions: The high pneumolysin antibody level in cases with URTI strongly indicates the pneumococcal infection. Pneumolysin antibody level even in little amounts (525pg/ml) with 87 sensitivity and 82 specificity is a suitable test for diagnosis of pneumococcal infection in children with URTI, but this test should be added to conventional culture (gold standard) and rapid urinary antigen test
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