9 research outputs found

    Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state

    Get PDF
    The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus. © 2012. The American Astronomical Society. All rights reserved

    Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

    Get PDF
    We report on the γ-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) γ-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size ≲0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∼10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society

    Assessment of health risks caused by overweight in children depending on the FTO gene rs9939609 polymorphism

    No full text
    In this study, we aimed to estimate the association between the rs9939609 FTO (fat mass and obesity associated) polymorphism and a risk of overweight in children living in the Baikal region. We performed a case – control study that included 113 schoolchildren living in industrial centers of the Baikal region (Irkutsk, Angarsk, and Ulan-Ude). Anthropometric parameters were measured and body mass index was calculated with its values being ranked in accordance with the WHO BMI curves depending on a sex and age. Genotyping of the rs9939609 FTO polymorphism was performed by allele-specific amplification with real-time results detection. To assess likelihood of an association between the FTO gene allele and overweight and obesity, relative risk (RR) and 95 % confidence interval (CI) were calculated. The assessment revealed the A allele of the rs9939609 FTO polymorphism to be by 1.29 times more frequent in the examined children with overweight and obesity (48.44 %) than in the children form the reference group (37.65 %). The FTO rs9939609 polymorphism was authentically associated with likelihood of elevated risks of overweight and obesity in children with the homozygous AA genotype (RR = 2.806, 95 % CI: 1.650–4.772; STD = 0.271). Our study confirms that the rs9939609 polymorphism of the FTO gene is a risk factor of overweight and obesity for children from the Baikal region who have the A allele of the homozygous AA genotype. Prevailing frequency of the TT genotype (29.2 %) as compared with the AA genotype (10.62) is likely due to influence of assimilation processes on urbanized territories in the Baikal region

    Immunogenic cell death induced by a new photodynamic therapy based on photosens and photodithazine

    No full text
    Background: Anti-cancer therapy is more successful when it can also induce an immunogenic form of cancer cell death (ICD). Therefore, when developing new treatment strategies, it is extremely important to choose methods that induce ICD and thereby activate anti-Tumor immune response leading to the most effective destruction of tumor cells. The aim of this work was to analyze whether the clinically widely used photosensitizers, photosens (PS) and photodithazine (PD), can induce ICD when used in photodynamic therapy (PDT). Methods: Cell death in murine glioma GL261 or fibrosarcoma MCA205 cells was induced by PS-or PD-PDT and cell death was analyzed by MTT or flow cytometry. Intracellular distribution of PS and PD was studied by using the laser scanning microscope. Calreticulin exposure and HMGB1 and ATP release were detected by flow cytometry, ELISA and luminescence assay, respectively. Immunogenicity in vitro was analyzed by co-culturing of dying cancer cells with bone-marrow derived dendritic cells (BMDCs) and rate of phagocytosis and maturation (CD11c+CD86+, CD11c+CD40+) of BMDCs and production of IL-6 in the supernatant were measured. In vivo immunogenicity was analyzed in mouse tumor prophylactic vaccination model. Results: We determined the optimal concentrations of the photosensitizers and found that at a light dose of 20 J/cm2 (\u3bbex 615-635 nm) both PS and PD efficiently induced cell death in glioma GL261 and fibrosarcoma MCA205 cells. We demonstrate that PS localized predominantly in the lysosomes and that the cell death induced by PS-PDT was inhibited by zVAD-fmk (apoptosis inhibitor) and by ferrostatin-1 and DFO (ferroptosis inhibitors), but not by the necroptosis inhibitor necrostatin-1 s. By contrast, PD accumulated in the endoplasmic reticulum and Golgi apparatus, and the cell death induced by PD-PDT was inhibited only by z-VAD-fmk. Dying cancer cells induced by PS-PDT or PD-PDT emit calreticulin, HMGB1 and ATP and they were efficiently engulfed by BMDCs, which then matured, became activated and produced IL-6. Using dying cancer cells induced by PS-PDT or PD-PDT, we demonstrate the efficient vaccination potential of ICD in vivo. Conclusions: Altogether, these results identify PS and PD as novel ICD inducers that could be effectively combined with PDT in cancer therapy

    Influence of plasma concentration of hsa-mir-370-3p and cyp2d6*4 on equilibrium concentration of phenazepam in patients with recurrent depressive disorder t

    No full text
    Introduction: Phenazepam is commonly administered to patients diagnosed with major depressive disorder. Some proportion of such patients do not show adequate response to treatment regimen containing phenazepam, whereas many of them experience type A adverse drug reactions. Previous studies showed that CYP2D6 RE IS involved in the biotransformation of phenazepam, the activity of which is highly dependent on the polymorphism of the gene encoding it. Objective. The objective of the study was to evaluate the impact of 1846G>A polymorphism of the CYP2D6 gene on the concentration/dose indicator of phenazepam, using findings on enzymatic activity of CYP2D6 (as evaluated by the 6M-THBC/pinoline ratio measurement) and on CYP2D6 expression level obtained by measuring the hsa-miR-370-3p plasma concentration levels in patients suffering from major depressive disorder. Material and methods: The study enrolled 191 patients with recurrent depressive disorder (age −40.0 ± 16.3 years). Treatment regimen included phenazepam in an average daily dose of 6.0 ± 2.3 mg per day. Treatment efficacy was assessed using the validated psychometric scales. Therapy safety was assessed using the UKU Side-Effect Rating Scale. For genotyping and estimation of the microRNA (miRNA) plasma levels we performed the real-time polymerase chain reaction (PCR Real-time). The activity of CYP2D6 was evaluated using the HPLC-MS/MS method by the content of the endogenous substrate of given isoenzyme and its metabolite in urine (6M-THBC/ pinoline). Therapeutic drug monitoring has been performed using HPLC-MS/MS. Results: Our findings didn’t reveal the statistically significant results in terms of the treatment efficacy evaluation (HAMA scores at the end of the treatment course): (GG) 6.0 [4.0; 8.0] and (GA) 6.0 [5.0; 7.8], p > 0.999; the statistical significance in the safety profile was not obtained (the UKU scores): (GG) 3.0 [2.0; 4.0] and (GA) 3.0 [3.0; 3.0], p > 0.999. We didn’t reveal a statistical significance for concentration/dose indicator of phenazepam in patients with different genotypes: (GG) 0.812 [0.558; 1.348] and (GA) 0.931 [0.630; 1.271], p = 0.645). Analysis of the results of the pharmacotranscriptomic part of the study didn’t show the statistically significant difference in the hsa-miR-370-3p plasma levels in patients with different genotypes: (GG) 22.5 [16.9; 29.8], (GA) 22.7 [15.7; 31.5], p = 0.695. At the same time, correlation analysis didn’t reveal a statistically significant relationship between the phenazepam efficacy profile evaluated by changes in HAMA scale scores and the hsa-miR-370-3p plasma concentration: rs = −0.01, p = 0.866. Also, we didn’t reveal the correlation between the miRNA concentration and safety profile: rs = 0.07, p = 0.348. Also we did not reveal the relationship between the CYP2D6 enzymatic activity (as evaluated by 6M-THBC/pinoline ratio measurement) and the hsa-miR370-3p plasma concentration: rs = −0.14, p = 0.056. At the same time, correlation analysis did not reveal a statistically significant relationship between the phenazepam concentration and the hsa-miR-370-3p plasma concentration: rs = −0.05, p = 0.468. Conclusion: The effect of genetic polymorphism of the CYP2D6 gene on the efficacy and safety profiles of phenazepam was not demonstrated in a group of 191 patients with recurrent depressive disorder. At the same time, hsa-miR-370-3p does not remain a promising biomarker for assessing the level of CYP2D6 expression, because it does not correlate with encoded isoenzyme activity. Psychopharmacology Bulletin. 2021;51(4):87–104. OT FOR REPRIN. © 2021, MedWorks Media LLC. All rights reserved
    corecore