123 research outputs found
The staining pattern of brilliant blue G during macular hole surgery: a clinicopathologic study
Purpose.: To describe the intraoperative staining pattern of the internal limiting membrane (ILM)-specific dye Brilliant Blue G (BBG) in a cohort of patients with idiopathic macular holes; to analyze the associations of the staining pattern with pre- and postoperative variables and to correlate the staining pattern with transmission electron microscopy (TEM) of the excised ILM.
Methods.: Fifty-five consecutive patients were studied. The staining pattern was divided into three subtypes based on the intraoperative appearance. The presence of a narrow rim of nonstaining around the macular hole (MH) edge was noted and measured. In the final 21 patients, the excised ILM was examined with TEM.
Results.: The pattern of staining observed was categorized as uniform in 33 patients (60%), patchy nonstaining in 17 (31%), and no visible staining in 5 (9%). The staining pattern correlated with the MH stage. In the patients with uniform or patchy staining, a nonstaining rim was observed in 26 (52%) of the 50. The presence of a rim was associated with a greater hole diameter and lower postoperative visual acuity. The stain pattern correlated significantly with the amount of cellular tissue on the vitreous side of the ILM on TEM, with a greater proportion of multicellular layer membranes and new collagen in the incomplete staining groups.
Conclusions.: A variety of nonstaining patterns around macular holes can be observed using BBG, and these patterns correlate to the amount of cellular tissue on the vitreous side of the ILM seen histologically. These patterns could be used to guide the ILM peeling requirement or extent in future studies
Optic disc pit maculopathy: a two-year nationwide prospective study.
Purpose
To identify the incidence, presenting features, treatment, and clinical course of optic disc pit maculopathy (ODPM) in the United Kingdom (UK).
Design
A 2-year nationwide prospective population-based study.
Subjects
All new incident cases of ODPM presenting to UK ophthalmologists using the British Ophthalmic Surveillance Unit monthly reporting system.
Methods
All reporting ophthalmologists were sent an initial questionnaire requesting data on previous medical and ophthalmic history, presentation details, investigation findings, and management. A further questionnaire was sent at 12 months post diagnosis to ascertain further outcome data.
Main Outcome Measures
Visual acuity at initial presentation, at 1 year, and after any intervention. Foveal involvement and optical coherence tomography (OCT) findings, including retinal layers affected, and the location and size of the optic disc pit. Management, including observation, vitrectomy, and associated procedures.
Results
There were 74 confirmed new cases, giving an annual incidence of approximately 1 per 2 million. Complete data were available on 70 patients (70 eyes) at baseline and 68 after 1 year. There were 35 (50%) female patients with a mean age of 35 years (range, 3–82 years). Visual acuity at baseline ranged from 6/5 to hand movements. In 43 patients (61%) subretinal fluid (SRF) was present, whereas 27 (39%) had intraretinal fluid only. The presence of SRF was associated with worse vision and foveal involvement. Of the 53 eyes initially observed with 1-year follow-up, 10 (19%) deteriorated and 9 (16%) improved on OCT; eyes with SRF were more likely to worsen and those without SRF were more likely to improve. Fifteen of the 70 patients (21%) at baseline had primary surgery and a further 10 had deferred surgery within 1 year of presentation; 19 of these 25 eyes (76%) showed anatomic success with a dry fovea at 1 year of follow-up, and 15 (60%) had a greater than 0.1 logMAR improvement in visual acuity.
Conclusion
The incidence and presenting features of ODPM were defined. Patients with SRF had worse vision and were more likely to deteriorate than patients with intraretinal fluid only. Surgery was anatomically successful in 75% of cases. Patients without SRF tended to remain stable with observation
The Extremely Luminous Quasar Survey in the Pan-STARRS 1 Footprint (PS-ELQS)
We present the results of the Extremely Luminous Quasar Survey in the
survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS;
PS1). This effort applies the successful quasar selection strategy of the
Extremely Luminous Survey in the Sloan Digital Sky Survey footprint
() to a much larger area
(). This spectroscopic survey targets the most
luminous quasars (; ) at intermediate redshifts
(). Candidates are selected based on a near-infrared JKW2 color cut
using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants.
Photometric redshifts () and star-quasar classifications for each
candidate are calculated from near-infrared and optical photometry using the
supervised machine learning technique random forests. We select 806 quasar
candidates at from a parent sample of 74318 sources. After
exclusion of known sources and rejection of candidates with unreliable
photometry, we have taken optical identification spectra for 290 of our 334
good PS-ELQS candidates. We report the discovery of 190 new quasars
and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS
candidates remain unobserved. Including all known quasars at , our
quasar selection method has a selection efficiency of at least . At lower
declinations we approximately triple the known
population of extremely luminous quasars. We provide the PS-ELQS quasar catalog
with a total of 592 luminous quasars (, ). This unique
sample will not only be able to provide constraints on the volume density and
quasar clustering of extremely luminous quasars, but also offers valuable
targets for studies of the intergalactic medium.Comment: 34 pages, 10 figures, accepted to ApJ
Significance of preoperative external limiting membrane height on visual prognosis in patients undergoing macular hole surgery
Purpose:
To investigate the association between the vertical elevation of the external limiting membrane (ELM) and visual outcome in patients undergoing surgery for idiopathic full-thickness macular hole.
Methods:
Retrospective observational study of a consecutive cohort of patients undergoing vitrectomy to treat macular hole. The greatest vertical height of the central ELM above the retinal pigment epithelium (ELM height) was measured on spectral domain optical coherence tomography preoperatively. The relationship of ELM height to other preoperative and postoperative variables, including macular hole width and height, and visual acuity was analyzed.
Results:
Data from 91 eyes of 91 patients who had undergone successful hole closure were included. The mean ELM height was 220 μm (range 100–394). There were significant correlations between the ELM height and the diameter of the hole, hole height, and worsening preoperative visual acuity. For holes less than 400 μm in width, better postoperative visual acuity was significantly predicted by a lower ELM height.
Conclusion:
The ELM height varies widely in idiopathic macular hole. It is higher in eyes where the hole is wider and also when the hole itself is higher. For holes of less than 400 μm in width, a lower ELM height is a strong independent predictor of a good postoperative outcome.
Reprint requests: David H. W. Steel, FRCOphth, Sunderland Eye Infirmary, Queen Alexandra Road, Sunderland, United Kingdom SR2 9HP, e-mail: [email protected]
Presented in part at the Floretina meeting, Florence, Italy, April 27, 2017.
D. H. W. Steel is a consultant to Alcon. The remaining authors have no financial/conflicting interests to disclose.
© 2018 by Ophthalmic Communications Society, Inc
Increased dispersion of oil from a deep water seabed release by energetic mesoscale eddies
Hydrodynamics play a critical role in determining the trajectory of an oil spill. Currents, stratification and mesoscale processes all contribute to how a spill behaves. Using an industry‑leading oil spill model, we compare forecasts of oil dispersion when forced with two different hydrodynamic models of the North-West European Shelf (7 km and 1.5 km horizontal resolution). This demonstrates how the trajectory of a deep water (>1000 m) release in the central Faroe-Shetland Channel is influenced by explicitly resolving mesoscale processes. The finer resolution hydrodynamic model dramatically enhances the horizontal dispersion of oil and transports pollutant further afield. This is a consequence of higher mesoscale variability. Stratification influences the depth of subsurface plume trapping and subsequently the far-field transport of oil. These results demonstrate that the choice of hydrodynamic model resolution is crucial when designing particle tracking or tracer release experiments
The Cutaneous Rabbit Illusion Affects Human Primary Sensory Cortex Somatotopically
We used functional magnetic resonance imaging (fMRI) to study neural correlates of a robust somatosensory illusion that can dissociate tactile perception from physical stimulation. Repeated rapid stimulation at the wrist, then near the elbow, can create the illusion of touches at intervening locations along the arm, as if a rabbit hopped along it. We examined brain activity in humans using fMRI, with improved spatial resolution, during this version of the classic cutaneous rabbit illusion. As compared with control stimulation at the same skin sites (but in a different order that did not induce the illusion), illusory sequences activated contralateral primary somatosensory cortex, at a somatotopic location corresponding to the filled-in illusory perception on the forearm. Moreover, the amplitude of this somatosensory activation was comparable to that for veridical stimulation including the intervening position on the arm. The illusion additionally activated areas of premotor and prefrontal cortex. These results provide direct evidence that illusory somatosensory percepts can affect primary somatosensory cortex in a manner that corresponds somatotopically to the illusory percept
The UK medical education database (UKMED) what is it?:Why and how might you use it?
The development of UKMED has not been directly funded by but has received support from the General Medical Council and Medical Schools Council as well as staff time from all participating organisations.Peer reviewedPublisher PD
Quenched Cold Accretion of a Large Scale Metal-Poor Filament due to Virial Shocking in the Halo of a Massive z=0.7 Galaxy
Using HST/COS/STIS and HIRES/Keck high-resolution spectra, we have studied a
remarkable HI absorbing complex at z=0.672 toward the quasar Q1317+277. The HI
absorption has a velocity spread of 1600 km/s, comprises 21 Voigt profile
components, and resides at an impact parameter of D=58 kpc from a bright, high
mass [log(M_vir/M_sun) ~ 13.7] elliptical galaxy that is deduced to have a 6
Gyr old, solar metallicity stellar population. Ionization models suggest the
majority of the structure is cold gas surrounding a shock heated cloud that is
kinematically adjacent to a multi-phase group of clouds with detected CIII, CIV
and OVI absorption, suggestive of a conductive interface near the shock. The
deduced metallicities are consistent with the moderate in situ enrichment
relative to the levels observed in the z ~ 3 Ly-alpha forest. We interpret the
HI complex as a metal-poor filamentary structure being shock heated as it
accretes into the halo of the galaxy. The data support the scenario of an early
formation period (z > 4) in which the galaxy was presumably fed by cold-mode
gas accretion that was later quenched via virial shocking by the hot halo such
that, by intermediate redshift, the cold filamentary accreting gas is
continuing to be disrupted by shock heating. Thus, continued filamentary
accretion is being mixed into the hot halo, indicating that the star formation
of the galaxy will likely remain quenched. To date, the galaxy and the HI
absorption complex provide some of the most compelling observational data
supporting the theoretical picture in which accretion is virial shocked in the
hot coronal halos of high mass galaxies.Comment: 20 pages, 9 figures, submitted to Ap
Clinical risk stratification of paediatric renal transplant recipients using C1q and C3d fixing of de novo donor-specific antibodies
Introduction: We have previously shown that children who developed de novo donor-specific human leukocyte antigen (HLA) antibodies (DSA) had greater decline in allograft function. We hypothesised that patients with complement-activating DSA would have poorer renal allograft outcomes. Methods: A total of 75 children developed DSA in the original study. The first positive DSA sample was subsequently tested for C1q and C3d fixing. The primary event was defined as 50% reduction from baseline estimated glomerular filtration rate and was analysed using the Kaplan–Meier estimator. Results: Of 65 patients tested, 32 (49%) and 23 (35%) tested positive for C1q and C3d fixing, respectively. Of the 32 C1q-positive (c1q+) patients, 13 (41%) did not show concomitant C3d fixing. The mean fluorescence intensity values of the original immunoglobulin G DSA correlated poorly with complement-fixing positivity (C1q: adjusted R2 0.072; C3d: adjusted R2 0.11; p < 0.05). C1q+ antibodies were associated with acute tubulitis [0.75 ± 0.18 (C1q+) vs. 0.25 ± 0.08 (C1q−) episodes per patient (mean ± standard error of the mean; p < 0.05] but not with worse long-term renal allograft dysfunction (median time to primary event 5.9 (C1q+) vs. 6.4 (C1q−) years; hazard ratio (HR) 0.74; 95% confidence ratio (CI) 0.30–1.81; p = 0.58]. C3d-positive (C3d+) antibodies were associated with positive C4d histological staining [47% (C3d+) vs. 20% (C3d−); p = 0.04] and with significantly worse long-term allograft dysfunction [median time to primary event: 5.6 (C3d+) vs. 6.5 (C3d−) years; HR 0.38; 95% CI 0.15–0.97; p = 0.04]. Conclusion: Assessment of C3d fixing as part of prospective HLA monitoring can potentially aid stratification of patients at the highest risk of long-term renal allograft dysfunction
Ejecta, Dust, and Synchrotron Radiation in B0540-69.3: A More Crab-Like Remnant than the Crab
We present near and mid-infrared observations of the pulsar-wind nebula (PWN)
B0540-69.3 and its associated supernova remnant made with the {\it Spitzer
Space Telescope}. We report detections of the PWN with all four IRAC bands, the
24 m band of MIPS, and the Infrared Spectrograph (IRS). We find no
evidence of IR emission from the X-ray/radio shell surrounding the PWN
resulting from the forward shock of the supernova blast wave. The flux of the
PWN itself is dominated by synchrotron emission at shorter (IRAC) wavelengths,
with a warm dust component longward of 20 m. We show that this dust
continuum can be explained by a small amount (\sim 1-3 \times 10^{-3} \msun)
of dust at a temperature of K, heated by the shock wave generated
by the PWN being driven into the inner edge of the ejecta. This is evidently
dust synthesized in the supernova. We also report the detection of several
lines in the spectrum of the PWN, and present kinematic information about the
PWN as determined from these lines. Kinematics are consistent with previous
optical studies of this object. Line strengths are also broadly consistent with
what one expects from optical line strengths. We find that lines arise from
slow ( km s) shocks driven into oxygen-rich clumps in the shell
swept-up by an iron-nickel bubble, which have a density contrast of relative to the bulk of the ejecta, and that faster shocks (
km s) in the hydrogen envelope are required to heat dust grains to
observed temperatures. We infer from estimates of heavy-element ejecta
abundances that the progenitor star was likely in the range of 20-25 .Comment: 46 pages, 10 figures, accepted for publication in Ap
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