732 research outputs found

    Plasma methionine sulfoxide in persons with familial Alzheimer’s disease mutations

    Get PDF
    The final, published version of this article is available at http://www.karger.com/?doi=10.1159/000338546.BACKGROUND: Convergent evidence suggests that oxidative stress plays a central role in the pathology of Alzheimer’s disease (AD). We asked if consequently, oxidation of methionine residues to methionine sulfoxide (MetO) increased in plasma proteins of persons carrying familial AD (FAD) mutations. METHODS: Plasma was collected from 31 persons from families harboring PSEN1 or APP mutations. Using Western blot analysis with a novel anti-MetO polyclonal antibody, MetO levels were measured and compared between FAD mutation carriers (MCs) and non-mutation carrying (NCs) kin. RESULTS: A MetO-positive 120 kDa gel band distinguished FAD MCs and NCs (mean 11.4 ± 2.8 vs. 4.0 ± 3.1, p = 0.02). In a subset of subjects for whom both measurements were available, MetO levels correlated well with plasma F2-isoprostane (r = 0.81, p < 0.001) and superoxide dismutase 1 (r = 0.52, p = 0.004) levels. CONCLUSIONS: Our data provide evidence for elevated MetO levels in persons carrying FAD mutations that correlate with other indices of oxidative stress and suggest that plasma oxidative stress markers may be useful for diagnosis of AD

    TDP-43 Proteinopathy in Aging: Associations with Risk-Associated Gene Variants and with Brain Parenchymal Thyroid Hormone Levels

    Get PDF
    TDP-43 proteinopathy is very prevalent among the elderly (affecting at least 25% of individuals over 85 years of age) and is associated with substantial cognitive impairment. Risk factors implicated in age-related TDP-43 proteinopathy include commonly inherited gene variants, comorbid Alzheimer\u27s disease pathology, and thyroid hormone dysfunction. To test parameters that are associated with aging-related TDP-43 pathology, we performed exploratory analyses of pathologic, genetic, and biochemical data derived from research volunteers in the University of Kentucky Alzheimer\u27s Disease Center autopsy cohort (n = 136 subjects). Digital pathologic methods were used to discriminate and quantify both neuritic and intracytoplasmic TDP-43 pathology in the hippocampal formation. Overall, 46.4% of the cases were positive for TDP-43 intracellular inclusions, which is consistent with results in other prior community-based cohorts. The pathologies were correlated with hippocampal sclerosis of aging (HS-Aging) linked genotypes. We also assayed brain parenchymal thyroid hormone (triiodothyronine [T3] and thyroxine [T4]) levels. In cases with SLCO1A2/IAPP or ABCC9 risk associated genotypes, the T3/T4 ratio tended to be reduced (p = .051 using 2-tailed statistical test), and in cases with low T3/T4 ratios (bottom quintile), there was a higher likelihood of HS-Aging pathology (p = .025 using 2-tailed statistical test). This is intriguing because the SLCO1A2/IAPP and ABCC9 risk associated genotypes have been associated with altered expression of the astrocytic thyroid hormone receptor (protein product of the nearby gene SLCO1C1). These data indicate that dysregulation of thyroid hormone signaling may play a role in age-related TDP-43 proteinopathy

    Exploring the Optical Transient Sky with the Palomar Transient Factory

    Get PDF
    The Palomar Transient Factory (PTF) is a wide-field experiment designed to investigate the optical transient and variable sky on time scales from minutes to years. PTF uses the CFH12k mosaic camera, with a field of view of 7.9 deg^2 and a plate scale of 1 asec/pixel, mounted on the the Palomar Observatory 48-inch Samuel Oschin Telescope. The PTF operation strategy is devised to probe the existing gaps in the transient phase space and to search for theoretically predicted, but not yet detected, phenomena, such as fallback supernovae, macronovae, .Ia supernovae and the orphan afterglows of gamma-ray bursts. PTF will also discover many new members of known source classes, from cataclysmic variables in their various avatars to supernovae and active galactic nuclei, and will provide important insights into understanding galactic dynamics (through RR Lyrae stars) and the Solar system (asteroids and near-Earth objects). The lessons that can be learned from PTF will be essential for the preparation of future large synoptic sky surveys like the Large Synoptic Survey Telescope. In this paper we present the scientific motivation for PTF and describe in detail the goals and expectations for this experiment.Comment: 15 pages, 6 figures, submitted to PAS

    Discovery of an intermediate-luminosity red transient in M51 and its likely dust-obscured, infrared-variable progenitor

    Get PDF
    We present the discovery of an optical transient (OT) in Messier 51, designated M51 OT2019-1 (also ZTF19aadyppr, AT 2019abn, ATLAS19bzl), by the Zwicky Transient Facility (ZTF). The OT rose over 15 days to an observed luminosity of Mr=13M_r=-13 (νLν=9×106 L{\nu}L_{\nu}=9\times10^6~L_{\odot}), in the luminosity gap between novae and typical supernovae (SNe). Spectra during the outburst show a red continuum, Balmer emission with a velocity width of 400\approx400 km s1^{-1}, Ca II and [Ca II] emission, and absorption features characteristic of an F-type supergiant. The spectra and multiband light curves are similar to the so-called "SN impostors" and intermediate-luminosity red transients (ILRTs). We directly identify the likely progenitor in archival Spitzer Space Telescope imaging with a 4.5 μ4.5~\mum luminosity of M[4.5]12.2M_{[4.5]}\approx-12.2 and a [3.6][4.5][3.6]-[4.5] color redder than 0.74 mag, similar to those of the prototype ILRTs SN 2008S and NGC 300 OT2008-1. Intensive monitoring of M51 with Spitzer further reveals evidence for variability of the progenitor candidate at [4.5] in the years before the OT. The progenitor is not detected in pre-outburst Hubble Space Telescope optical and near-IR images. The optical colors during outburst combined with spectroscopic temperature constraints imply a higher reddening of E(BV)0.7E(B-V)\approx0.7 mag and higher intrinsic luminosity of Mr14.9M_r\approx-14.9 (νLν=5.3×107 L{\nu}L_{\nu}=5.3\times10^7~L_{\odot}) near peak than seen in previous ILRT candidates. Moreover, the extinction estimate is higher on the rise than on the plateau, suggestive of an extended phase of circumstellar dust destruction. These results, enabled by the early discovery of M51 OT2019-1 and extensive pre-outburst archival coverage, offer new clues about the debated origins of ILRTs and may challenge the hypothesis that they arise from the electron-capture induced collapse of extreme asymptotic giant branch stars.Comment: 21 pages, 5 figures, published in ApJ

    The type Iax supernova, SN 2015H A white dwarf deflagration candidate

    Get PDF
    We present results based on observations of SN 2015H which belongs to the small group of objects similar to SN 2002cx, otherwise known as type Iax supernovae. The availability of deep pre-explosion imaging allowed us to place tight constraints on the explosion epoch. Our observational campaign began approximately one day post-explosion, and extended over a period of about 150 days post maximum light, making it one of the best observed objects of this class to date. We find a peak magnitude of Mr = −17.27± 0.07, and a (Δm15)r = 0.69 ± 0.04. Comparing our observations to synthetic spectra generated from simulations of deflagrations of Chandrasekhar mass carbon-oxygen white dwarfs, we find reasonable agreement with models of weak deflagrations that result in the ejection of ~0.2 M⊙ of material containing ~0.07 M⊙ of 56Ni. The model light curve however, evolves more rapidly than observations, suggesting that a higher ejecta mass is to be favoured. Nevertheless, empirical modelling of the pseudo-bolometric light curve suggests that ≲0.6 M⊙ of material was ejected, implying that the white dwarf is not completely disrupted, and that a bound remnant is a likely outcome

    PTF11eon/SN2011dh: Discovery of a Type IIb Supernova From a Compact Progenitor in the Nearby Galaxy M51

    Get PDF
    On May 31, 2011 UT a supernova (SN) exploded in the nearby galaxy M51 (the Whirlpool Galaxy). We discovered this event using small telescopes equipped with CCD cameras, as well as by the Palomar Transient Factory (PTF) survey, and rapidly confirmed it to be a Type II supernova. Our early light curve and spectroscopy indicates that PTF11eon resulted from the explosion of a relatively compact progenitor star as evidenced by the rapid shock-breakout cooling seen in the light curve, the relatively low temperature in early-time spectra and the prompt appearance of low-ionization spectral features. The spectra of PTF11eon are dominated by H lines out to day 10 after explosion, but initial signs of He appear to be present. Assuming that He lines continue to develop in the near future, this SN is likely a member of the cIIb (compact IIb; Chevalier and Soderberg 2010) class, with progenitor radius larger than that of SN 2008ax and smaller than the eIIb (extended IIb) SN 1993J progenitor. Our data imply that the object identified in pre-explosion Hubble Space Telescope images at the SN location is possibly a companion to the progenitor or a blended source, and not the progenitor star itself, as its radius (~10^13 cm) would be highly inconsistent with constraints from our post-explosion photometric and spectroscopic data

    Association between canine leishmaniosis and Ehrlichia canis co-infection: a prospective case-control study

    Get PDF
    Abstract Background In the Mediterranean basin, Leishmania infantum is a major cause of disease in dogs, which are frequently co-infected with other vector-borne pathogens (VBP). However, the associations between dogs with clinical leishmaniosis (ClinL) and VBP co-infections have not been studied. We assessed the risk of VBP infections in dogs with ClinL and healthy controls. Methods We conducted a prospective case-control study of dogs with ClinL (positive qPCR and ELISA antibody for L. infantum on peripheral blood) and clinically healthy, ideally breed-, sex- and age-matched, control dogs (negative qPCR and ELISA antibody for L. infantum on peripheral blood) from Paphos, Cyprus. We obtained demographic data and all dogs underwent PCR on EDTA-blood extracted DNA for haemoplasma species, Ehrlichia/Anaplasma spp., Babesia spp., and Hepatozoon spp., with DNA sequencing to identify infecting species. We used logistic regression analysis and structural equation modelling (SEM) to evaluate the risk of VBP infections between ClinL cases and controls. Results From the 50 enrolled dogs with ClinL, DNA was detected in 24 (48%) for Hepatozoon spp., 14 (28%) for Mycoplasma haemocanis, 6 (12%) for Ehrlichia canis and 2 (4%) for Anaplasma platys. In the 92 enrolled control dogs, DNA was detected in 41 (45%) for Hepatozoon spp., 18 (20%) for M. haemocanis, 1 (1%) for E. canis and 3 (3%) for A. platys. No Babesia spp. or “Candidatus Mycoplasma haematoparvum” DNA was detected in any dog. No statistical differences were found between the ClinL and controls regarding age, sex, breed, lifestyle and use of ectoparasitic prevention. A significant association between ClinL and E. canis infection (OR = 12.4, 95% CI: 1.5–106.0, P = 0.022) was found compared to controls by multivariate logistic regression. This association was confirmed using SEM, which further identified that younger dogs were more likely to be infected with each of Hepatozoon spp. and M. haemocanis, and dogs with Hepatozoon spp. were more likely to be co-infected with M. haemocanis. Conclusions Dogs with ClinL are at a higher risk of co-infection with E. canis than clinically healthy dogs. We recommend that dogs diagnosed with ClinL should be tested for E. canis co-infection using PCR
    corecore