452 research outputs found
Fish oil-based emulsion for the treatment of parenteral nutrition associated liver disease in an adult patient
Background & aims: Reversal of parenteral nutrition associated liver disease with fish oil emulsion (FO) has been reported in infants. We report a similar case in an adult patient. Methods: A 58 year-old female on home parenteral nutrition for a short bowel syndrome due to Crohn's disease, showed a progressive worsening of liver steatosis, and a persistent increase of the plasma liver function tests (LFTs). LFTs, serum alpha-tochopherol, red blood cell membrane fatty acids and liver histology were evaluated before and after an 8 month treatment with FO. Results: The patient's LFT's improved. There was an increase of the n-3 and a decrease of the n-6 series of fatty acids in erythrocyte membrane. There was an approximate 30% increase in vitamin E status. Before FO, liver histology showed a non-alcoholic steatohepatitis with grade 2 steatosis and inflammation and stage 3 fibrosis. After the treatment, steatosis and inflammation were grade 1, whereas fibrosis remained at stage 3. Conclusions: Infusion of FO was associated with consistent changes of cell membrane fatty acid structure and with mild improvement of vitamin E status. A potential role of FO in decreasing liver steatosis and inflammation with no change of liver fibrosis might be suggested. © 2010 European Society for Clinical Nutrition and Metabolism
Naloxone blockade of amphetamine place preference conditioning
Amphetamine and naloxone were examined in place conditioning, in order to study possible interactions between endogenous opioids and catecholamines in reinforcement. After initial preferences were determined, animals were conditioned with amphetamine alone (1.0 mg/kg SC), naloxone alone (0.02, 0.2 or 2.0 mg/kg SC) or combinations of amphetamine plus naloxone. A reliable, long-lasting preference for the compartment associated with amphetamine was observed, reflecting the reinforcing properties of this drug. No preference or aversion was observed in animals that received saline in both compartments. Naloxone (0.02, 0.2 and 2.0 mg/kg) produced a dose-dependent place aversion; while the lowest dose had effects similar to saline, the higher doses produced significant place aversions. Naloxone, at all three doses examined, prevented the ability of amphetamine to produce a place preference. Thus, the lowest dose of naloxone, having no effects alone in place conditioning was still able to block the reinforcing effects of amphetamine. These results suggest that the reinforcing effects of amphetamine are dependent on activation of opiate receptors, and provide further evidence that interactions between endogenous opioids and catecholamines may be important in reinforcement.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46337/1/213_2005_Article_BF02244190.pd
Analytical maximum likelihood estimation of stellar magnetic fields
The polarised spectrum of stellar radiation encodes valuable information on
the conditions of stellar atmospheres and the magnetic fields that permeate
them. In this paper, we give explicit expressions to estimate the magnetic
field vector and its associated error from the observed Stokes parameters. We
study the solar case where specific intensities are observed and then the
stellar case, where we receive the polarised flux. In this second case, we
concentrate on the explicit expression for the case of a slow rotator with a
dipolar magnetic field geometry. Moreover, we also give explicit formulae to
retrieve the magnetic field vector from the LSD profiles without assuming mean
values for the LSD artificial spectral line. The formulae have been obtained
assuming that the spectral lines can be described in the weak field regime and
using a maximum likelihood approach. The errors are recovered by means of the
hermitian matrix. The bias of the estimators are analysed in depth.Comment: accepted for publication in MNRA
Anomalous circular polarization profiles in the He I 1083.0 nm multiplet from solar spicules
We report Stokes vector observations of solar spicules and a prominence in
the He I 1083 nm multiplet carried out with the Tenerife Infrared Polarimeter.
The observations show linear polarization profiles that are produced by
scattering processes in the presence of a magnetic field. After a careful data
reduction, we demonstrate the existence of extremely asymmetric Stokes V
profiles in the spicular material that we are able to model with two magnetic
components along the line of sight, and under the presence of atomic
orientation in the energy levels that give rise to the multiplet. We discuss
some possible scenarios that can generate the atomic orientation in spicules.
We stress the importance of spectropolarimetric observations across the limb to
distinguish such signals from observational artifacts.Comment: accepted for publication in Ap
A Statistical Inference Method for Interpreting the CLASP Observations
On 3rd September 2015, the Chromospheric Lyman-Alpha SpectroPolarimeter
(CLASP) successfully measured the linear polarization produced by scattering
processes in the hydrogen Lyman- line of the solar disk radiation,
revealing conspicuous spatial variations in the and signals. Via
the Hanle effect the line-center and amplitudes encode information
on the magnetic field of the chromosphere-corona transition region (TR), but
they are also sensitive to the three-dimensional structure of this corrugated
interface region. With the help of a simple line formation model, here we
propose a statistical inference method for interpreting the Lyman-
line-center polarization observed by CLASP.Comment: Accepted for publication in The Astrophysical Journa
CLASP Constraints on the Magnetization and Geometrical Complexity of the Chromosphere-Corona Transition Region
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a suborbital
rocket experiment that on 3rd September 2015 measured the linear polarization
produced by scattering processes in the hydrogen Ly- line of the solar
disk radiation, whose line-center photons stem from the chromosphere-corona
transition region (TR). These unprecedented spectropolarimetric observations
revealed an interesting surprise, namely that there is practically no
center-to-limb variation (CLV) in the line-center signals. Using an
analytical model, we first show that the geometrical complexity of the
corrugated surface that delineates the TR has a crucial impact on the CLV of
the and line-center signals. Secondly, we introduce a statistical
description of the solar atmosphere based on a three-dimensional (3D) model
derived from a state-of-the-art radiation magneto-hydrodynamic simulation. Each
realization of the statistical ensemble is a 3D model characterized by a given
degree of magnetization and corrugation of the TR, and for each such
realization we solve the full 3D radiative transfer problem taking into account
the impact of the CLASP instrument degradation on the calculated polarization
signals. Finally, we apply the statistical inference method presented in a
previous paper to show that the TR of the 3D model that produces the best
agreement with the CLASP observations has a relatively weak magnetic field and
a relatively high degree of corrugation. We emphasize that a suitable way to
validate or refute numerical models of the upper solar chromosphere is by
confronting calculations and observations of the scattering polarization in
ultraviolet lines sensitive to the Hanle effect.Comment: Accepted for publication in The Astrophysical Journal Letter
Recent Advances in Chromospheric and Coronal Polarization Diagnostics
I review some recent advances in methods to diagnose polarized radiation with
which we may hope to explore the magnetism of the solar chromosphere and
corona. These methods are based on the remarkable signatures that the
radiatively induced quantum coherences produce in the emergent spectral line
polarization and on the joint action of the Hanle and Zeeman effects. Some
applications to spicules, prominences, active region filaments, emerging flux
regions and the quiet chromosphere are discussed.Comment: Review paper to appear in "Magnetic Coupling between the Interior and
the Atmosphere of the Sun", eds. S. S. Hasan and R. J. Rutten, Astrophysics
and Space Science Proceedings, Springer-Verlag, 200
5-ASA Suppositories in Hemorrhoidal Disease
Forty patients with active hemorrhoidal disease were entered into this double-blind trial, 20 of whom were randomized to treatment with 5-aminosalicylic acid (5-ASA) (500 mg) suppositories. Clinical and sigmoidoscopic assessment was carried out before the start of the trial and after two weeks of treatment. At the end of the study, 5-ASA suppositories showed results superior to those of placebo for all parameters evaluated (P<0.01). There were no adverse events reported related to the use of suppositories. 5-ASA suppositories are a valid therapeutic approach for hemorrhoidal disease as it reduces the intensity of all symptoms and significantly decreases congestion of the hemorrhoidal plexus
- âŠ