Fundamental Parameters Line Profile Fitting in Laboratory Diffractometers.

The fundamental parameters approach to line profile fitting uses physically based models to generate the line profile shapes. Fundamental parameters profile fitting (FPPF) has been used to synthesize and fit data from both parallel beam and divergent beam diffractometers. The refined parameters are determined by the diffractometer configuration. In a divergent beam diffractometer these include the angular aperture of the divergence slit, the width and axial length of the receiving slit, the angular apertures of the axial Soller slits, the length and projected width of the x-ray source, the absorption coefficient and axial length of the sample. In a parallel beam system the principal parameters are the angular aperture of the equatorial analyser/Soller slits and the angular apertures of the axial Soller slits. The presence of a monochromator in the beam path is normally accommodated by modifying the wavelength spectrum and/or by changing one or more of the axial divergence parameters. Flat analyzer crystals have been incorporated into FPPF as a Lorentzian shaped angular acceptance function. One of the intrinsic benefits of the fundamental parameters approach is its adaptability any laboratory diffractometer. Good fits can normally be obtained over the whole 20 range without refinement using the known properties of the diffractometer, such as the slit sizes and diffractometer radius, and emission profile

Impacto da COVID-19 na Cirurgia de Transplantação Corneana: Primeiro EuCornea Educational Webinar

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Paraneoplastic pemphigus with clinical features of lichen planus associated with low-grade B cell lymphoma

BACKGROUND: Neoplasia-induced lichen planus is described as a cell-mediated reaction to unknown epithelial antigens. Paraneoplastic pemphigus (PNP), characterized by the presence of a specific array of autoantibodies, probably represents a different form of presentation of the same autoimmune syndrome where the mucocutaneous expression depends on the dominant pathologic mechanism. METHODS: The authors report a case of PNP with predominant lichen planus-like lesions and review the relevant literature. We observed a 74-year-old female with vesico-bullous, erosive, target-shaped and flat papular lichenoid lesions on the lower legs, palms and soles, evolving for 3 weeks. Histopathology revealed a lichenoid dermatitis. Direct immunofluorescence showed C3 deposition around keratinocytes and epidermal IgG intranuclear deposition. Indirect immunofluorescence revealed circulating IgG with intercellular staining on rat bladder substrate. Immunoblotting demonstrated bands of 130, 190, 210 and 250 kDa antigens. A pararenal B cell lymphoma was found. RESULTS: Oral corticotherapy with 40 mg prednisolone daily was initiated with a good cutaneous response. Four months later, cyclophosphamide (50 mg/day) was introduced because of a discrete enlargement of the pararenal mass. The patient died on the seventh month of follow up as a result of respiratory insufficiency. CONCLUSION: PNP has different forms of presentation and the lack of a consensus about diagnostic criteria may contribute to underdiagnosed cases. Advances on the knowledge of the sensitivity and specificity of diagnostic criteria have allowed a better accuracy of diagnosis

Secondary Endothelial Keratoplasty—A Narrative Review of the Outcomes of Secondary Corneal Endothelial Allografts

Background: We review the literature on the efficacy and safety outcomes of secondary Descemet stripping endothelial keratoplasty (DSEK) and Descemet membrane endothelial keratoplasty (DMEK). Methods: Literature search of English-written publications up to September 27, 2020 in PubMed database, using the terms "endothelial keratoplasty" in combination with keywords "secondary" or "repeat." In addition, we manually searched the references of the primary articles. Results: Twenty-seven studies (n = 651 eyes) were retained and reviewed, including 10 studies on repeat DSEK, 8 studies on repeat DMEK, 6 studies of DMEK following DSEK, and 3 studies of DSEK after failed DMEK. All studies reported significant improvement in visual acuity after secondary endothelial keratoplasty (EK). Twelve studies compared visual outcomes between primary and secondary EK, reporting conflicting findings. Sixteen studies reported endothelial cell loss rates after secondary EK, and only 1 study reported significantly increased endothelial cell loss rates compared with primary EK. Allograft rejection episodes occurred in 1.8% of eyes (range, 0%-50%). Six studies compared complication rates between primary and secondary EK eyes, and only 1 study found a higher median number of complications. However, 2 studies reported higher regraft failure rates compared with primary EK eyes. Conclusions: Secondary EK is surgically feasible and renders significant visual improvement after failed primary EK, although it is not clear whether visual outcomes and allograft survival are comparable with primary EK, raising the question of whether secondary EK eyes are "low risk" as primary EK eyes. Further larger, prospective studies are encouraged to obtain additional quality data on secondary corneal endothelial allotransplantation.info:eu-repo/semantics/publishedVersio

Outcomes of Cystoid Macular Edema Following Descemet's Membrane Endothelial Keratoplasty in a Referral Center for Keratoplasty in Spain: Retrospective Study

The aim of this study was to analyze the outcomes of eyes with visually significant cystoid macular œdema (vs-CMO) after Descemet membrane endothelial keratoplasty (DMEK) in a referral center for keratoplasty in Spain. We conducted a retrospective, single-surgeon case series of eyes that developed post-DMEK vs-CMO performed between January 2011 and December 2020. Data collected included: indication for DMEK; biometric data; ocular comorbidities; past medical history; time to detection of vs-CMO after DMEK (T, weeks); best-corrected visual acuity (BCVA, logMAR) and central retinal thickness (CRT, µm) at diagnosis of vs-CMO, after resolution of CMO, and at last follow-up; and management strategy. Main outcomes analyzed were incidence of vs-CMO, improvement in BCVA and CRT after treatment of vs-CMO. Of 291 consecutive DMEK surgeries, 14 eyes of 13 patients (4.8%) developed vs-CMO. Five patients (38.5%) had history of CMO, and 28.6% of eyes had ophthalmic comorbidities. Median (P25-P75) T was 4 (3-10) weeks. Treatment success was observed in 12/13 eyes (92.3%), two of which required second-line treatment. In successful cases (median time-to-resolution 3.0 (2.0-3.5) months), median BCVA improved from 0.60 (0.40-0.80) logMAR to 0.30 (0.15-0.40) logMAR (p = 0.002) after treatment, and median CRT improved from 582.5 (400.0-655.0) µm to 278.0 (258.0-294.0) µm (p = 0.005). In our study, we found a 4.8% rate of post-DMEK vs-CMO, with most cases occurring in the first 3 months after surgery. Good functional and anatomical outcomes are expected in most eyes, without treatment-related complications or implications in graft outcomes. Additional studies are encouraged to determine a standardized protocol for post-DMEK vs-CMO.info:eu-repo/semantics/publishedVersio

Soluble human Suppression of Tumorigenicity 2 is associated with endoscopic activity in patients with moderate-to-severe ulcerative colitis treated with golimumab

Suppressor of Tumorigenicity 2 (ST2) is an IL33 receptor detected in the mucosa and serum of ulcerative colitis (UC) patients. We evaluated soluble ST2 (sST2) as a surrogate biomarker of disease outcome and therapeutic response, in moderate-to-severe UC patients treated with golimumab.Agência financiadora Merck Sharp and Dohme, Lda, Portugal MK8259-22info:eu-repo/semantics/publishedVersio

Choroidal Binarization Analysis: Clinical Application

Introduction: Image processing of optical coherence tomography scans through binarization techniques represent a non-invasive way to separately asses and measure choroidal components, in vivo. In this review, we systematically search the scientific literature regarding binarization studies published so far. Methods: A systematic research was conducted at PubMed database, including English literature articles for all of the following terms in various combinations: binarization, choroid/al, enhanced depth spectral domain/swept source optic coherence tomography, and latest publications up to November 2018 were reviewed. Results: Thirty-seven articles were included and analyzed regarding studied disease, binarization method, studied variables, and outcomes. Most of the studies have focused on the more common retinal pathologies, such as age-related macular degeneration, central serous chorioretinopathy and diabetic retinopathy but binarization techniques have also been applied to the study of choroidal characteristics in ocular inflammatory diseases, corneal dystrophies and in postsurgical follow-up. Advantages and disadvantages of binarization techniques are also discussed. Conclusion: Binarization of choroidal images seems to represent a promising approach to study choroid subcomponents in an increasingly detailed manner.info:eu-repo/semantics/publishedVersio

Prevalence and Characteristics of Osteochondrosis in Lusitano Purebred Horses

Objectives: This is the first comprehensive study in Lusitanos that aims to study the radiographic prevalence and localisation of osteochondrosis in different joints. Methods: A radiographic protocol of the metacarpo/ metatarsophalangeal, tarsocrural and femoropatellar joints was done in 302 Lusitanos, and findings were clas- sified using a 0-4 scale: 0 - normal joint contours; 1 – minimal (minimal and smooth flattening); 2 – mild (irregularly flattening); 3 - moderate (presence of a small fragment, presence of a small rounded defect) and 4 – severe (large or multiple fragments, with a large irregular defect). Scores 1 and 2 were considered to represent OC while scores 3 and 4 corresponded to OCD Results: Abnormal findings were present in 53.31% of the horses. Most were stallions (88.74%), and the mean age was 5 ± 2.48 years (range of 1 to 12 years old). The prevalence of OC (36.75%) was higher than OCD (16.56%). The most affected joint were hocks (39.73%), followed by fetlocks (26.48%) and stifles (3.3%). OC was registered in 34.43% in hocks, 14.9% in fetlocks and 2.31% in stifles. The presence of fragments (OCD) was recorded in 6.95% of the cases in the hock, 8.93% in the fetlocks and 1.65% in the stifle. Conclusions: This Lusitano horse population has pres- ented a high prevalence of osteochondral lesions, with a low prevalence of OCD. This study is important to ensure a rational use of Lusitano and a prospective study is required to determine the genetic variability regarding OC/OCD in this breed