8 research outputs found
OCT Signs of Early Atrophy in Age-Related Macular Degeneration: Interreader Agreement: Classification of Atrophy Meetings Report 6.
PURPOSE: To determine the interreader agreement for incomplete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA) and complete RPE and outer retinal atrophy (cRORA) and their related features in age-related macular degeneration (AMD). DESIGN: Interreader agreement study. PARTICIPANTS: Twelve readers from 6 reading centers. METHODS: After formal training, readers qualitatively assessed 60 OCT B-scans from 60 eyes with AMD for 9 individual features associated with early atrophy and performed 7 different annotations to quantify the spatial extent of OCT features within regions of interest. The qualitative and quantitative features were used to derive the presence of iRORA and cRORA and also in an exploratory analysis to examine if agreement could be improved using different combinations of features to define OCT atrophy. MAIN OUTCOME MEASURES: Interreader agreement based on Gwet's first-order agreement coefficient (AC1) for qualitatively graded OCT features and classification of iRORA and cRORA, and smallest real difference (SRD) for quantitatively graded OCT features. RESULTS: Substantial or better interreader agreement was observed for all qualitatively graded OCT features associated with atrophy (AC1 = 0.63-0.87), except for RPE attenuation (AC1 = 0.46) and disruption (AC1 = 0.26). The lowest SRD for the quantitatively graded horizontal features was observed for the zone of choroidal hypertransmission (± 190.8 μm). Moderate agreement was found for a 3-category classification of no atrophy, iRORA, and cRORA (AC1 = 0.53). Exploratory analyses suggested a significantly higher level of agreement for a 3-category classification using (1) no atrophy; (2) presence of inner nuclear layer and outer plexiform layer subsidence, or a hyporeflective wedge-shaped band, as a less severe atrophic grade; and (3) the latter plus an additional requirement of choroidal hypertransmission of 250 μm or more for a more severe atrophic grade (AC1 = 0.68; P = 0.013). CONCLUSIONS: Assessment of iRORA and cRORA, and most of their associated features, can be performed relatively consistently and robustly. A refined combination of features to define early atrophy could further improve interreader agreement
Exploring protein myristoylation in Toxoplasma gondii
Toxoplasma gondii is an important human and veterinary pathogen and the causative agent of toxoplasmosis, a potentially severe disease especially in immunocompromised or congenitally infected humans. Current therapeutic compounds are not well-tolerated, present increasing resistance, limited efficacy and require long periods of treatment. On this context, searching for new therapeutic targets is crucial to drug discovery. In this sense, recent works suggest that N-myristoyltransferase (NMT), the enzyme responsible for protein myristoylation that is essential in some parasites, could be the target of new anti-parasitic compounds. However, up to date there is no information on NMT and the extent of this modification in T. gondii. In this work, we decided to explore T. gondii genome in search of elements related with the N-myristoylation process. By a bioinformatics approach it was possible to identify a putative T. gondii NMT (TgNMT). This enzyme that is homologous to other parasitic NMTs, presents activity in vitro, is expressed in both intra- and extracellular parasites and interacts with predicted TgNMT substrates. Additionally, NMT activity seems to be important for the lytic cycle of Toxoplasma gondii. In parallel, an in silico myristoylome predicts 157 proteins to be affected by this modification. Myristoylated proteins would be affecting several metabolic functions with some of them being critical for the life cycle of this parasite. Together, these data indicate that TgNMT could be an interesting target of intervention for the treatment of toxoplasmosis.Fil: Alonso, Andrés Mariano. Universidad Nacional de San Martin. Instituto Tecnológico de Chascomús - Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto Tecnológico de Chascomús; Argentina. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; ArgentinaFil: Turowski, Valeria Rosana. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata; ArgentinaFil: Ruiz, Diego Mario. Universidad Nacional de La Plata. Centro Regional de Estudios Genómicos; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata; ArgentinaFil: Orelo, Barbara D.. The Scripps Research Institute; Estados UnidosFil: Moresco, James J.. The Scripps Research Institute; Estados UnidosFil: Yates, John R.. The Scripps Research Institute; Estados UnidosFil: Corvi, Maria Martha. Universidad Nacional de San Martin. Instituto Tecnológico de Chascomús - Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Instituto Tecnológico de Chascomús; Argentin
Reticular Pseudodrusen: Interreader Agreement of Evaluation on OCT Imaging in Age-Related Macular Degeneration
Purpose: To determine the interreader agreement for reticular pseudodrusen (RPD) assessment on combined infrared reflectance (IR) and OCT imaging in the early stages of age-related macular degeneration across a range of different criteria to define their presence. Design: Interreader agreement study. Participants: Twelve readers from 6 reading centers. Methods: All readers evaluated 100 eyes from individuals with bilateral large drusen for the following: (1) the presence of RPD across a range of different criteria and (2) the number of Stage 2 or 3 RPD lesions (from 0 to ≥ 5 lesions) on an entire OCT volume scan and on a selected OCT B-scan. Supportive information was available from the corresponding IR image. Main Outcome Measures: Interreader agreement, as assessed by Gwet’s first-order agreement coefficient (AC1). Results: When evaluating an entire OCT volume scan, there was substantial interreader agreement for the presence of any RPD, any or ≥ 5 Stage 2 or 3 lesions, and ≥ 5 definite lesions on en face IR images corresponding to Stage 2 or 3 lesions (AC1 = 0.60–0.72). On selected OCT B-scans, there was also moderate-to-substantial agreement for the presence of any RPD, any or ≥ 5 Stage 2 or 3 lesions (AC1 = 0.58–0.65) and increasing levels of agreement with increasing RPD stage (AC1 = 0.08, 0.56, 0.78, and 0.99 for the presence of any Stage 1, 2, 3, and 4 lesions, respectively). There was substantial agreement regarding the number of Stage 2 or 3 lesions on an entire OCT volume scan (AC1 = 0.68), but only fair agreement for this evaluation on selected B-scans (AC1 = 0.30). Conclusions: There was generally substantial or near-substantial—but not near-perfect—agreement for assessing the presence of RPD on entire OCT volume scans or selected B-scans across a range of differing RPD criteria. These findings underscore how interreader variability would likely contribute to the variability of findings related to the clinical associations of RPD. The low levels of agreement for assessing RPD number on OCT B-scans underscore the likely challenges of quantifying RPD extent with manual grading. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references
Targeted resequencing of the microRNAome and 3′UTRome reveals functional germline DNA variants with altered prevalence in epithelial ovarian cancer
Ovarian cancer is a major cause of cancer deaths, yet there have been few known genetic risk factors identified, the best known of which are disruptions in protein coding sequences (BRCA1 and 2). Recent findings indicate that there are powerful genetic markers of cancer risk outside of these regions, in the noncoding mRNA control regions. To identify additional cancer-associated, functional non-protein-coding sequence germline variants associated with ovarian cancer risk, we captured DNA regions corresponding to all validated human microRNAs and the 3′ untranslated regions (UTRs) of ~ 6000 cancer-associated genes from 31 ovarian cancer patients. Multiple single-nucleotide polymorphisms in the 3′UTR of the vascular endothelial growth factor receptor/FLT1, E2F2 and PCM1 oncogenes were highly enriched in ovarian cancer patients compared with the 1000 Genome Project. Sequenom validation in a case–control study (267 cases and 89 controls) confirmed a novel variant in the PCM1 3′UTR is significantly associated with ovarian cancer (P = 0.0086). This work identifies a potential new ovarian cancer locus and further confirms that cancer resequencing efforts should not ignore the study of noncoding regions of cancer patients
RET as a diagnostic and therapeutic target in sporadic and hereditary endocrine tumors
The RET gene encodes a receptor tyrosine kinase that is expressed in neural crest-derived cell lineages. The RET receptor plays a crucial role in regulating cell proliferation, migration, differentiation, and survival through embryogenesis. Activating mutations in RET lead to the development of several inherited and noninherited diseases. Germline point mutations are found in the cancer syndromes multiple endocrine neoplasia (MEN) type 2, including MEN 2A and 2B, and familial medullary thyroid carcinoma. These syndromes are autosomal dominantly inherited. The identification of mutations associated with these syndromes has led to genetic testing to identify patients at risk for MEN 2 and familial medullary thyroid carcinoma and subsequent implementation of prophylactic thyroidectomy in mutation carriers. In addition, more than 10 somatic rearrangements of RET have been identified from papillary thyroid carcinomas. These mutations, as those found in MEN2, induce oncogenic activation of the RET tyrosine kinase domain via different mechanisms, making RET an excellent candidate for the design of molecular targeted therapy. Recently, various kinds of therapeutic approaches, such as tyrosine kinase inhibition, gene therapy with dominant negative RET mutants, monoclonal antibodies against oncogene products, and nuclease-resistant aptamers that recognize and inhibit RET have been developed. The use of these strategies in preclinical models has provided evidence that RET is indeed a potential target for selective cancer therapy. However, a clinically useful therapeutic option for treating patients with RET-associated cancer is still not available