529 research outputs found
A Fourier optics approach to evaluate the astrometric performance of MICADO
We present our investigation into the impact of wavefront errors on high
accuracy astrometry using Fourier Optics. MICADO, the upcoming near-IR imaging
instrument for the Extremely Large Telescope, will offer capabilities for
relative astrometry with an accuracy of 50 micro arcseconds ({\mu}as). Due to
the large size of the point spread function (PSF) compared to the astrometric
requirement, the detailed shape and position of the PSF on the detector must be
well understood. Furthermore, because the atmospheric dispersion corrector of
MICADO is a moving component within an otherwise mostly static instrument, it
might not be sufficient to perform a simple pre-observation calibration.
Therefore, we have built a Fourier Optics framework, allowing us to evaluate
the small changes in the centroid position of the PSF as a function of
wavefront error. For a complete evaluation, we model both the low order surface
form errors, using Zernike polynomials, and the mid- and high-spatial
frequencies, using Power Spectral Density analysis. The described work will
then make it possible, performing full diffractive beam propagation, to assess
the expected astrometric performance of MICADO.Comment: 13 pages, 13 figures, to be submitted to the SPIE Astronomical
Telescopes & Instrumentation 2020 conferenc
Clinical characterization of 66 patients with congenital retinal disease due to the deep-intronic c.2991+1655A>G mutation in CEP290
Purpose: To describe the phenotypic spectrum of retinal disease caused by the c.2991+1655A>G mutation in CEP290 and to compare disease severity between homozygous and compound heterozygous patients.
Methods: Medical records were reviewed for best-corrected visual acuity (BCVA), age of onset, fundoscopy descriptions. Foveal outer nuclear layer (ONL) and ellipsoid zone (EZ) presence was assessed using spectral-domain optical coherence tomography (SD-OCT). Differences between compound heterozygous and homozygous patients were analyzed based on visual performance and visual development.
Results: A total of 66 patients were included. The majority of patients had either light perception or no light perception. In the remaining group of 14 patients, median BCVA was 20/195 Snellen (0.99 LogMAR; range 0.12-1.90) for the right eye, and 20/148 Snellen (0.87 LogMAR; range 0.22-1.90) for the left. Homozygous patients tended to be more likely to develop light perception compared to more severely affected compound heterozygous patients (P = 0.080) and are more likely to improve from no light perception to light perception (P = 0.022) before the age of 6 years. OCT data were available in 12 patients, 11 of whom had retained foveal ONL and EZ integrity up to 48 years (median 23 years) of age.
Conclusions: Homozygous patients seem less severely affected compared to their compound-heterozygous peers. Improvement of visual function may occur in the early years of life, suggesting a time window for therapeutic intervention up to the approximate age of 17 years. This period may be extended by an intact foveal ONL and EZ on OCT
Reduction of heparan sulphate-associated anionic sites in the glomerular basement membrane of rats with streptozotocin-induced diabetic nephropathy
Non-Q wave myocardial infarction: Identification of high and low risk subsets by clinical variables
[This corrects the article DOI: 10.1371/journal.pone.0160243.]
Evaluation of diagnostic and therapeutic management of hypertensive crises in a Dutch emergency department:results from a clinical audit
Antisense oligonucleotide-based splicing correction in individuals with leber congenital amaurosis due to compound heterozygosity for the c.2991+1655A>G mutation in CEP290
Leber congenital amaurosis (LCA) is a rare inherited retinal disorder affecting approximately 1:50,000 people worldwide. So far, mutations in 25 genes have been associated with LCA, with CEP290 (encoding the Centrosomal protein of 290 kDa) being the most frequently mutated gene. The most recurrent LCA-causing CEP290 mutation, c.2991+1655A>G, causes the insertion of a pseudoexon into a variable proportion of CEP290 transcripts. We previously demonstrated that antisense oligonucleotides (AONs) have a high therapeutic potential for patients homozygously harbouring this mutation, although to date, it is unclear whether rescuing one single allele is enough to restore CEP290 function. Here, we assessed the AON efficacy at RNA, protein and cellular levels in samples that are compound heterozygous for this mutation, together with a protein-truncating mutation in CEP290. We demonstrate that AONs can efficiently restore splicing and increase protein levels. However, due to a high variability in ciliation among the patient-derived cell lines, the efficacy of the AONs was more difficult to assess at the cellular level. This observation points towards the importance of the severity of the second allele and possibly other genetic variants present in each individual. Overall, AONs seem to be a promising tool to treat CEP290-associated LCA, not only in homozygous but also in compound heterozygous carriers of the c.2991+1655A>G variant
Roles of Trm9- and ALKBH8-like proteins in the formation of modified wobble uridines in Arabidopsis tRNA
Uridine at the wobble position of tRNA is usually modified, and modification is required for accurate and efficient protein translation. In eukaryotes, wobble uridines are modified into 5-methoxycarbonylmethyluridine (mcm5U), 5-carbamoylmethyluridine (ncm5U) or derivatives thereof. Here, we demonstrate, both by in vitro and in vivo studies, that the Arabidopsis thaliana methyltransferase AT1G31600, denoted by us AtTRM9, is responsible for the final step in mcm5U formation, thus representing a functional homologue of the Saccharomyces cerevisiae Trm9 protein. We also show that the enzymatic activity of AtTRM9 depends on either one of two closely related proteins, AtTRM112a and AtTRM112b. Moreover, we demonstrate that AT1G36310, denoted AtALKBH8, is required for hydroxylation of mcm5U to (S)-mchm5U in tRNAGlyUCC, and has a function similar to the mammalian dioxygenase ALKBH8. Interestingly, atalkbh8 mutant plants displayed strongly increased levels of mcm5U, and also of mcm5Um, its 2′-O-ribose methylated derivative. This suggests that accumulated mcm5U is prone to further ribose methylation by a non-specialized mechanism, and may challenge the notion that the existence of mcm5U- and mcm5Um-containing forms of the selenocysteine-specific tRNASec in mammals reflects an important regulatory process. The present study reveals a role in for several hitherto uncharacterized Arabidopsis proteins in the formation of modified wobble uridines
Urinary liver-type fatty-acid binding protein is independently associated with graft failure in outpatient kidney transplant recipients
Urinary liver-type fatty acid-binding protein (uL-FABP) is a biomarker of kidney hypoxia and ischemia, and thus offers a novel approach to identify early kidney insults associated with increased risk of graft failure in outpatient kidney transplant recipients (KTR). We investigated whether uL-FABP is associated with graft failure and whether it improves risk prediction. We studied a cohort of 638 outpatient KTR with a functional graft ≥1-year. During a median follow-up of 5.3 years, 80 KTR developed graft failure. uL-FABP (median 2.11, interquartile range 0.93–7.37 µg/24"/>h) was prospectively associated with the risk of graft failure (hazard ratio 1.75; 95% confidence interval 1.27–2.41 per 1-SD increment; P =.001), independent of potential confounders including estimated glomerular filtration rate and proteinuria. uL-FABP showed excellent discrimination ability for graft failure (c-statistic of 0.83) and its addition to a prediction model composed by established clinical predictors of graft failure significantly improved the c-statistic to 0.89 (P for F-test <.001). These results were robust to several sensitivity analyses. Further validation studies are warranted to evaluate the potential use of a risk-prediction model including uL-FABP to improve identification of outpatient KTR at high risk of graft failure in clinical care
Efficacy of Carbonic Anhydrase Inhibitors on Cystoid Fluid Collections and Visual Acuity in Patients with X-Linked Retinoschisis
Purpose: To date, there is no standard treatment regimen for carbonic anhydrase inhibitors (CAIs) in X-linked retinoschisis (XLRS) patients. This retrospective study aims to evaluate the efficacy of CAIs on visual acuity and cystoid fluid collections (CFC) in XRLS patients in Dutch and Belgian tertiary referral centers. Design: Retrospective cohort study. Participants: Forty-two patients with XLRS. Methods: In total, 42 patients were enrolled. To be included, patients had to have previous treatment with an oral CAI (acetazolamide), a topical CAI (brinzolamide/dorzolamide), or a combination of an oral and a topical CAI for at least 4 consecutive weeks. We evaluated the effect of the CAI on best-corrected visual acuity (BCVA) and central foveal thickness (CFT) on OCT. Main Outcome Measures: Central foveal thickness and BCVA. Results: The median age at the baseline visit of the patients in this cohort study was 14.7 (range, 43.6) years, with a median (interquartile range [IQR]) follow-up period of 4.0 (2.2–5.2) years. During the follow-up period, 25 patients were treated once with an oral CAI (60%), 24 patients were treated once with a topical CAI (57%), and 11 patients were treated once with a combination of both topical and oral CAI (26%). We observed a significant reduction of CFT for oral CAI by 14.37 μm per 100 mg per day (P < 0.001; 95% confidence interval [CI], −19.62 to −9.10 μm) and for topical CAI by 7.52 μm per drop per day (P = 0.017; 95% CI, −13.67 to −1.32 μm). The visual acuity changed significantly while on treatment with oral CAI by −0.0059 logMAR per 100 mg (P = 0.008; 95% CI, −0.010 to −0.0013 logMAR). Seven patients (17%) had side effects leading to treatment discontinuation. Conclusions: Our data indicate that treatment with (oral) CAI may be beneficial for short-term management of CFC in patients with XLRS. Despite a significant reduction in CFT, the change in visual acuity was modest and not of clinical significance. Nonetheless, the anatomic improvement of the central retina in these patients may be of value to create an optimal retinal condition for future potential treatment options such as gene therapy. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.</p
Efficacy of Carbonic Anhydrase Inhibitors on Cystoid Fluid Collections and Visual Acuity in Patients with X-Linked Retinoschisis
Purpose: To date, there is no standard treatment regimen for carbonic anhydrase inhibitors (CAIs) in X-linked retinoschisis (XLRS) patients. This retrospective study aims to evaluate the efficacy of CAIs on visual acuity and cystoid fluid collections (CFC) in XRLS patients in Dutch and Belgian tertiary referral centers. Design: Retrospective cohort study. Participants: Forty-two patients with XLRS. Methods: In total, 42 patients were enrolled. To be included, patients had to have previous treatment with an oral CAI (acetazolamide), a topical CAI (brinzolamide/dorzolamide), or a combination of an oral and a topical CAI for at least 4 consecutive weeks. We evaluated the effect of the CAI on best-corrected visual acuity (BCVA) and central foveal thickness (CFT) on OCT. Main Outcome Measures: Central foveal thickness and BCVA. Results: The median age at the baseline visit of the patients in this cohort study was 14.7 (range, 43.6) years, with a median (interquartile range [IQR]) follow-up period of 4.0 (2.2–5.2) years. During the follow-up period, 25 patients were treated once with an oral CAI (60%), 24 patients were treated once with a topical CAI (57%), and 11 patients were treated once with a combination of both topical and oral CAI (26%). We observed a significant reduction of CFT for oral CAI by 14.37 μm per 100 mg per day (P < 0.001; 95% confidence interval [CI], −19.62 to −9.10 μm) and for topical CAI by 7.52 μm per drop per day (P = 0.017; 95% CI, −13.67 to −1.32 μm). The visual acuity changed significantly while on treatment with oral CAI by −0.0059 logMAR per 100 mg (P = 0.008; 95% CI, −0.010 to −0.0013 logMAR). Seven patients (17%) had side effects leading to treatment discontinuation. Conclusions: Our data indicate that treatment with (oral) CAI may be beneficial for short-term management of CFC in patients with XLRS. Despite a significant reduction in CFT, the change in visual acuity was modest and not of clinical significance. Nonetheless, the anatomic improvement of the central retina in these patients may be of value to create an optimal retinal condition for future potential treatment options such as gene therapy. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.</p
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