597 research outputs found
Prevention of Dermatologic Side Effects of Bimatoprost 0.03% Topical Therapy
PURPOSE: To investigate the efficacy of reducing the drop-skin contact to prevent dermatologic side effects of bimatoprost 0.03% topical therapy. DESIGN: Prospective, randomized, single-blinded, internally controlled study. METHODS: Enrolled subjects started bimatoprost 0.03% therapy once at night in both eyes and were instructed to wipe selectively only one eye (eye 1) with an adsorbent pad during and after drops administration for four months. The fellow eye acted as the internal control. Eyelash growth, regional skin hypertrichosis, and pigmentation on the periocular skin were assessed at baseline and during the four months of follow-up. RESULTS: A lower incidence of eyelash growth and skin pigmentation in the inferonasal pericanthal region were observed in eye 1. The incidence of pigmentation in the inferotemporal skin region and skin hypertrichosis were similar in the two eyes. CONCLUSION: The reduction of the drop,skin contact affects the regional incidence and the extent of dermatologic skin changes that are related to bimatoprost 0.03% topical therapy
Levels of plasma homocysteine in pseudoexfoliation glaucoma.
BACKGROUND: To examine levels of serum homocysteine (Hcy), vitamin B12 and folic acid in patients with pseudoexfoliation glaucoma (PEXG), primary open-angle glaucoma (POAG), and healthy control subjects.
METHODS: This study included 36 patients with PEXG, 40 with POAG, and 40 age-matched healthy subjects. Fasting plasma Hcy concentrations and levels of serum vitamin B12 and folic acid were measured using competitive chemiluminescent enzyme immunoassay; values exceeding 14 μm/l were considered elevated. RESULTS:
Mean plasma Hcy was significantly higher in PEXG (16.55 ± 7.23 μm/l) compared with POAG (13.91 ± 3.61 μm/l) and controls (13.12 ± 5.13 μm/l) (p = 0.03 and p = 0.0007 respectively). There were no statistical differences in serum vitamin B12 and folic acid levels among PEXG, POAG and control subjects (p > 0.05). A moderate, although statistically significant, relationship between Hcy and folic acid levels was found in the PEXG group (R(2) = 0.23, p = 0.003). Hcy levels were found not to be related with folic acid or vitamin B12 in either POAG or control subjects.
CONCLUSIONS: In this study, plasma Hcy is significantly higher in PEXG group than the POAG and control groups. Hyper-Hcy might play a role in the pathogenesis of PEXG. Hyper-Hcy may be an independent factor stressing vasculopathy in addition to pseudoexfoliation, so might be a modifiable risk factor for PEXG
Retinal functional changes measured by frequency-doubling technology in patients treated with hydroxychloroquine.
BACKGROUND:
Antimalarial drugs such as chloroquine (CQ) and hydroxychloroquine (HCQ) are mainly used in the treatment of rheumatologic diseases, and their use may be associated with irreversible retinal toxicity. Previous studies indicate early paracentral visual field loss (Humphrey 10-2) in patients taking HCQ". These paracentral defects appear before changes in other clinical parameters as visual acuity and fundoscopy. The mechanism of CQ toxicity remains unclear. It was reported that toxic doses of CQ administered for as long as 4.5 years to Rhesus monkeys caused an initial dramatic effect on ganglion cells, followed later by photoreceptors and RPE degeneration. The purpose of this study is to explore early retinal functional changes measured by frequency-doubling technology (FDT) in patients treated with hydroxychloroquine (HCQ).
METHODS:
Forty-eight eyes of 48 subjects treated with hydroxychloroquine (HCQ), with no signs of retinal toxicity, and 36 eyes of 36 age and sex-matched healthy subjects were enrolled in this cross-sectional, prospective, observational, case control study. Functional testing included frequency-doubling Humphrey-matrix perimetry (FDP), white-on-white Humphrey visual field perimetry (HFA), using the 24-2 and 10-2 threshold programs, multifocal electroretinogram (mfERG, Veris 4.9) and low contrast sensitivity (CS) measurement.
RESULTS:
FDP mean deviation (MD) was found to be significantly reduced in HCQ-treated patients compared to controls both in the 24-2 (-1.38 ± 2.41 dB vs 0.21 ± 1.83 dB, p < 0.01) and in the 10-2 program (-0.97 ± 2.88 dB vs 0.15 ± 1.72 dB, p < 0.01). FDP pattern standard deviation (PSD) was found to be significantly worse in HCQ-treated patients compared to controls both in the 24-2 (2.70 ± 0.65 dB vs 2.41 ± 0.31 dB, p < 0.01 and in the 10-2 program (2.86 ± 0.48 dB vs 2.48 ± 0.39 dB, p < 0.01). HFA PSD and CS was also significantly reduced in HCQ patients, while response amplitude densities (RAD) were similar between patients and controls. A statistically significant difference in the ratio of the 5°-10° RAD and the 0°-2.5° RAD (0.31 ± 0.08 vs 0.36 ± 0.07 respectively, p < 0.05) was found between groups.
CONCLUSION:
Frequency doubling perimetry could be useful to detect early retinal impairment in patients treated with hydroxychloroquine
Comparison of Travoprost and Bimatoprost plus timolol fixed combinations in open-angle glaucoma patients previously treated with latanoprost plus timolol fixed combination
To compare the ocular hypotensive effect of bimatoprost plus timolol and travoprost plus timolol fixed combinations in glaucoma patients whose disease was controlled but had not reached their target intraocular pressure (IOP) with the fixed combination of latanoprost plus timolol
GROND coverage of the main peak of Gamma-Ray Burst 130925A
Prompt or early optical emission in gamma-ray bursts is notoriously difficult
to measure, and observations of the dozen cases show a large variety of
properties. Yet, such early emission promises to help us achieve a better
understanding of the GRB emission process(es).
We performed dedicated observations of the ultra-long duration (T90 about
7000 s) GRB 130925A in the optical/near-infrared with the 7-channel "Gamma-Ray
Burst Optical and Near-infrared Detector" (GROND) at the 2.2m MPG/ESO
telescope. We detect an optical/NIR flare with an amplitude of nearly 2 mag
which is delayed with respect to the keV--MeV prompt emission by about 300--400
s. The decay time of this flare is shorter than the duration of the flare (500
s) or its delay.
While we cannot offer a straightforward explanation, we discuss the
implications of the flare properties and suggest ways toward understanding it.Comment: 9 pages, 9 figures, accepted for publ. in A&
Dynamics of a small neutrally buoyant sphere in a fluid and targeting in Hamiltonian systems
We show that, even in the most favorable case, the motion of a small
spherical tracer suspended in a fluid of the same density may differ from the
corresponding motion of an ideal passive particle. We demonstrate furthermore
how its dynamics may be applied to target trajectories in Hamiltonian systems.Comment: See home page http://lec.ugr.es/~julya
Rapid planetesimal formation in turbulent circumstellar discs
The initial stages of planet formation in circumstellar gas discs proceed via
dust grains that collide and build up larger and larger bodies (Safronov 1969).
How this process continues from metre-sized boulders to kilometre-scale
planetesimals is a major unsolved problem (Dominik et al. 2007): boulders stick
together poorly (Benz 2000), and spiral into the protostar in a few hundred
orbits due to a head wind from the slower rotating gas (Weidenschilling 1977).
Gravitational collapse of the solid component has been suggested to overcome
this barrier (Safronov 1969, Goldreich & Ward 1973, Youdin & Shu 2002). Even
low levels of turbulence, however, inhibit sedimentation of solids to a
sufficiently dense midplane layer (Weidenschilling & Cuzzi 1993, Dominik et al.
2007), but turbulence must be present to explain observed gas accretion in
protostellar discs (Hartmann 1998). Here we report the discovery of efficient
gravitational collapse of boulders in locally overdense regions in the
midplane. The boulders concentrate initially in transient high pressures in the
turbulent gas (Johansen, Klahr, & Henning 2006), and these concentrations are
augmented a further order of magnitude by a streaming instability (Youdin &
Goodman 2005, Johansen, Henning, & Klahr 2006, Johansen & Youdin 2007) driven
by the relative flow of gas and solids. We find that gravitationally bound
clusters form with masses comparable to dwarf planets and containing a
distribution of boulder sizes. Gravitational collapse happens much faster than
radial drift, offering a possible path to planetesimal formation in accreting
circumstellar discs.Comment: To appear in Nature (30 August 2007 issue). 18 pages (in referee
mode), 3 figures. Supplementary Information can be found at 0708.389
A single-shot optical linear polarimeter for asteroid studies
Polarimetric studies of minor Solar System bodies are useful to access physical parameters, such as albedo and diameter, which are both important and difficult to derive by other techniques. Current activities in this field are limited since most instruments adopted in recent observing campaigns involve photomultipliers detectors. These sensors are suitable for observations of objects with fast polarization variations, but usually suffer from low quantum efficiency. This severely limits the number of accessible targets. For asteroids, the polarization evolves slowly enough to allow more sensitive albeit slower detectors (CCD-based polarimeters). However, polarimetric measurement accuracy may be hampered with usual "sequential" polarimeters. Indeed, retarder plate swapping time, readout and exposure time add up. Consequently, the time laps between complementary polarization measurements (some minutes) may be non-negligible in some cases, compared to the evolution time of the polarization parameters. Moreover, polarimetric accuracy may also be limited by airmass variations between complementary exposures. We are developing a new "single-shot" CCD polarimeter based on a "double-Wollaston" configuration already described in literature [9][10]. This allows simultaneous acquisition of the three Stokes parameters I, Q, U without any moving parts. So, the linear polarization degree can be measured accurately, even for targets with fast polarization and/or airmass variations. Presently, the polarization analyzer is in calibration phase, and will be installed soon at the F/12.5 Cassegrain focus of the West telescope at the "Centre Pédagogique Planète et Univers" facility (C2PU, Observatoire de la Côte d'Azur, Plateau de Calern, France)
(16) Psyche: A mesosiderite-like asteroid?
Asteroid (16) Psyche is the target of the NASA Psyche mission. It is
considered one of the few main-belt bodies that could be an exposed
proto-planetary metallic core and that would thus be related to iron
meteorites. Such an association is however challenged by both its near- and
mid-infrared spectral properties and the reported estimates of its density.
Here, we aim to refine the density of (16) Psyche to set further constraints on
its bulk composition and determine its potential meteoritic analog.
We observed (16) Psyche with ESO VLT/SPHERE/ZIMPOL as part of our large
program (ID 199.C-0074). We used the high angular resolution of these
observations to refine Psyche's three-dimensional (3D) shape model and
subsequently its density when combined with the most recent mass estimates. In
addition, we searched for potential companions around the asteroid. We derived
a bulk density of 3.99\,\,0.26\,gcm for Psyche. While such
density is incompatible at the 3-sigma level with any iron meteorites
(7.8\,gcm), it appears fully consistent with that of
stony-iron meteorites such as mesosiderites (density
4.25\,cm). In addition, we found no satellite in our images
and set an upper limit on the diameter of any non-detected satellite of
1460\,\,200}\,m at 150\,km from Psyche (0.2\%\,\,R, the
Hill radius) and 800\,\,200\,m at 2,000\,km (3\%\,\,).
Considering that the visible and near-infrared spectral properties of
mesosiderites are similar to those of Psyche, there is merit to a
long-published initial hypothesis that Psyche could be a plausible candidate
parent body for mesosiderites.Comment: 16 page
- …