Multicenter Validation of Deep Learning Algorithm ROP.AI for the Automated Diagnosis of Plus Disease in ROP.

Purpose: Retinopathy of prematurity (ROP) is a sight-threatening vasoproliferative retinal disease affecting premature infants. The detection of plus disease, a severe form of ROP requiring treatment, remains challenging owing to subjectivity, frequency, and time intensity of retinal examinations. Recent artificial intelligence (AI) algorithms developed to detect plus disease aims to alleviate these challenges; however, they have not been tested against a diverse neonatal population. Our study aims to validate ROP.AI, an AI algorithm developed from a single cohort, against a multicenter Australian cohort to determine its performance in detecting plus disease. Methods: Retinal images captured during routine ROP screening from May 2021 to February 2022 across five major tertiary centers throughout Australia were collected and uploaded to ROP.AI. AI diagnostic output was compared with one of five ROP experts. Sensitivity, specificity, negative predictive value, and area under the receiver operator curve were determined. Results: We collected 8052 images. The area under the receiver operator curve for the diagnosis of plus disease was 0.75. ROP.AI achieved 84% sensitivity, 43% specificity, and 96% negative predictive value for the detection of plus disease after operating point optimization. Conclusions: ROP.AI was able to detect plus disease in an external, multicenter cohort despite being trained from a single center. Algorithm performance was demonstrated without preprocessing or augmentation, simulating real-world clinical applicability. Further training may improve generalizability for clinical implementation. Translational Relevance: These results demonstrate ROP.AI's potential as a screening tool for the detection of plus disease in future clinical practice and provides a solution to overcome current diagnostic challenges.

Short-term homeostatic regulation of blood/interstitial fluid Ca2+ concentration by the scales of anadromous sea trout Salmo trutta L. during smoltification and migration.

The elasmoid scales of anadromous sea trout Salmo trutta L. represent a significant internal reservoir of Ca2+ . Although more is known about long-term remodelling of scales in response to calciotropic challenges encountered during smoltification and migration, very little is known about the contribution made by scales to the short-term, minute-to-minute regulation of Ca2+ homeostasis in the extracellular fluid (ECF) during these phases of the life cycle. This gap in the knowledge is partly due to the technical challenges involved in measuring small Ca2+ fluxes around the scales of live fish in real time. Here, this study describes exfoliating, mounting and culturing scales and their resident cells from parr, smolt and adult sea trout from a freshwater environment, as well as from adult sea trout caught in sea or brackish water. All the scales were then examined using an extracellular, non-invasive, surface-scanning Ca2+ -sensitive microelectrode. The authors quantified the Ca2+ fluxes, in the absence of any systemic or local regulators, into and out of scales on both the episquamal and hyposquamal sides under different extracellular calcemic challenges set to mimic a variety of ECF-Ca2+ concentrations. Scales from the life-cycle stages as well as from adult fish taken from sea, brackish or fresh water all showed a consistent efflux or influx of Ca2+ under hypo- or hypercalcemic conditions, respectively. What were considered to be isocalcemic conditions resulted in minimal flux of Ca2+ in either direction, or in the case of adult scales, a consistent but small influx. Indeed, adult scales appeared to display the largest flux densities in either direction. These new data extend the current understanding of the role played by fish scales in the short-term, minute-to-minute homeostatic regulation of ECF-Ca2+ concentration, and are similar to those recently reported from zebrafish Danio rerio scales. This suggests that this short-term regulatory response might be a common feature of teleost scales.

Flow-cytometry detection of fluorescent magnetic nanoparticle clusters increases sensitivity of dengue immunoassay.

We report a flow-cytometry based method capable of detecting a range of analytes by monitoring the analyte-induced clustering of magnetic and fluorescent nanoparticles with flow cytometry. Using the dengue viral antigen (NS1) as an example, antibodies were conjugated to magnetic and fluorescent nanoparticles in a sandwich immunoassay format. These nanoparticles formed clusters when NS1 was present in a sample and the cluster formation was directly proportional to the concentration of antigen. Simultaneous flow cytometry measurement of cluster size, as detected by the forward scatter channel, combined with fluorescence intensity led to a reduction in the assay background signal, resulting in improved analytical sensitivity. We were able to detect 2.5 ng mL-1 of NS1 in serum samples by quantifying the clusters, a two-log fold improvement in the assay limit of detection over total fluorescence quantification alone.

Building a Global, Pediatric Vascular Access Registry: A Scoping Review of Trial Outcomes and Quality Indicators to Inform Evidence-Based Practice.

BACKGROUND: Internationally, there is a lack of comparative vascular access (VA) data for pediatric clinicians and organizations to benchmark outcomes, evaluate quality initiatives, and improve practice. A VA registry is needed to address these knowledge and data capture gaps. OBJECTIVES: To determine the range and heterogeneity of VA outcome measures or quality indicators reported in randomized controlled trials (RCTs) and clinical registries, to inform development of a homogeneous, reliable, minimum dataset for a pediatric VA registry. METHODS: Scoping review framework. A systematic search for RCTs reporting VA outcomes in pediatrics and neonates was undertaken in the Cochrane library, EMBASE, CINAHL, PubMed, MEDLINE, and EBSCO using a medical subject headings and key words related to VA and pediatrics. We included RCTs of children (0-18 years) reporting any VA outcome. We identified clinical registries reporting VA data in children (0-18) through web-based searches using key words related to VA and clinical or quality registries. Additional registries were identified through peer consultation. The frequency and scope of outcome measures and quality indicators were extracted from trials and registries and evaluated. RESULTS: From 93 RCTs included, 214 different VA measures were reported, reflecting 14 outcome domains. The most commonly reported outcome domains were insertion (44 RCTs; 47%), noninfectious complications (33 RCTs; 35%), and infectious complications (30 RCTs; 32%). Of the 22 registries identified, VA-associated infection was the main quality indicator routinely collected (12 registries; 55%). Outcomes such as mechanical complications and patient-reported outcomes were infrequently collected. LINKING EVIDENCE TO ACTION: Vascular access outcomes reported in pediatric and neonatal RCTs are highly heterogeneous. Internationally, clinical registries currently collect minimal VA data with the exception of infection outcomes. A core dataset of reliable, relevant measures to children and clinicians for VA device quality is needed. This will enable a VA registry that facilitates inter-institutional and international benchmarking.

Hyaluronan molecular weight is controlled by UDP-N-acetylglucosamine concentration in Streptococcus zooepidemicus.

The molecular weight of hyaluronan is important for its rheological and biological function. The molecular mechanisms underlying chain termination and hence molecular weight control remain poorly understood, not only for hyaluronan synthases but also for other beta-polysaccharide synthases, e.g. cellulose, chitin, and 1,3-betaglucan synthases. In this work, we manipulated metabolite concentrations in the hyaluronan pathway by overexpressing the five genes of the hyaluronan synthesis operon in Streptococcus equi subsp. zooepidemicus. Overexpression of genes involved in UDP-glucuronic acid biosynthesis decreased molecular weight, whereas overexpression of genes involved in UDP-N-acetylglucosamine biosynthesis increased molecular weight. The highest molecular mass observed was at 3.4 +/- 0.1 MDa twice that observed in the wild-type strain, 1.8 +/- 0.1 MDa. The data indicate that (a) high molecular weight is achieved when an appropriate balance of UDP-N-acetylglucosamine and UDP-glucuronic acid is achieved, (b) UDP-N-acetylglucosamine exerts the dominant effect on molecular weight, and (c) the wild-type strain has suboptimal levels of UDP-N-acetylglucosamine. Consistent herewith molecular weight correlated strongly (rho = 0.84, p = 3 x 10(-5)) with the concentration of UDP-N-acetylglucosamine. Data presented in this paper represent the first model for hyaluronan molecular weight control based on the concentration of activated sugar precursors. These results can be used to engineer strains producing high molecular weight hyaluronan and may provide insight into similar polymerization mechanisms in other polysaccharides.

BspA (CyuC) in Lactobacillus fermentum BR11 is a highly expressed high-affinity L-cystine-binding protein.

The BspA protein of Lactobacillus fermentum BR11 (BR11) is a cell envelope constituent that is similar to known solute-binding proteins and putative adhesins. BspA is required for L-cystine uptake and oxidative defense and is likely to be an L-cystine-binding protein. The aim of this study was to directly measure L-cystine-BspA binding and BspA expression. De-energized BR11 cells bound radiolabelled L-cystine with a Kd of 0.2 microM. A bspA mutant could not bind L-cystine. L-cystine-BR11 binding was unaffected by large excesses of L-glutamine, L-methionine, or collagen, indicating L-cystine specificity. BR11 and the bspA mutant were identical in their abilities to bind L-cysteine, indicating that L-cysteine is not a BspA ligand. BspA expression levels were deduced from radiolabelled L-cystine binding and it was found that there are 1-2 x 10(5) BspA molecules per cell, and that expression is slightly higher under oxidizing conditions. It is proposed that BspA be renamed CyuC.

Cystine uptake prevents production of hydrogen peroxide by Lactobacillus fermentum BR11.

BspA is an abundant surface protein from Lactobacillus fermentum BR11, and is required for normal cystine uptake. In previous studies, a mutant strain deficient in BspA (L. fermentum PNG201) was found to be sensitive to oxidative stress. In this study, the biochemical basis for this was explored. It was found that under aerobic batch culture conditions in de Mann-Rogosa-Sharpe medium, both L. fermentum BR11 and PNG201 entered stationary phase due to hydrogen peroxide accumulation. However, this took place at a lower optical density for PNG201 than for BR11. Measurements of hydrogen peroxide levels revealed that the BspA mutant strain overproduces this compound. Addition of 6 mM cystine to aerobic cultures was found to prevent hydrogen peroxide production by both the BR11 and PNG201 strains, but lower cystine concentrations depressed hydrogen peroxide production in BR11 more efficiently than in PNG201. Each mole of cystine was able to prevent the production of several moles of hydrogen peroxide by L. fermentum BR11, suggesting that hydrogen peroxide breakdown is dependent upon a thiol that cycles between reduced and oxidized states. It was concluded that peroxide breakdown by L. fermentum BR11 is dependent upon exogenous cystine. It is most probable that the imported L-cystine is catabolized by a cystathionine lyase and then converted into a thiol reductant for a peroxidase.

Expression of a streptococcal glucosyltransferase as a fusion to a solute-binding protein in Lactobacillus fermentum BR11.

BspA is a non-covalently anchored cystine-binding protein from Lactobacillus fermentum BR11. It has previously been used to present antigens derived from infectious organisms on the L. fermentum BR11 cell surface. In this study, the capacity of BspA to present a very large polypeptide was tested. A temperature sensitive plasmid was constructed that encodes a 175-kDa chimeric protein consisting of a fusion between BspA and an N-terminally truncated derivative of the Streptococcus salivarius ATCC 25975 glucosyltransferase GtfJ. This plasmid was introduced into the L. fermentum genome. Integrants were able to incorporate 20-40 nmol sucrose derived glucose into glucan per ml culture per optical density unit. The glucosyltransferase activity was external to the cytoplasmic membrane and bound to the cell. Unlike native BspA, the BspA-GtfJ fusion could not be removed from the cell by 5 M LiCl wash.