Neuroimaging Scoring Tools to Differentiate Inflammatory Central Nervous System Small-Vessel Vasculitis: A Need for Artificial Intelligence/Machine Learning?-A Scoping Review.

Neuroimaging has a key role in identifying small-vessel vasculitis from common diseases it mimics, such as multiple sclerosis. Oftentimes, a multitude of these conditions present similarly, and thus diagnosis is difficult. To date, there is no standardized method to differentiate between these diseases. This review identifies and presents existing scoring tools that could serve as a starting point for integrating artificial intelligence/machine learning (AI/ML) into the clinical decision-making process for these rare diseases. A scoping literature review of EMBASE and MEDLINE included 114 articles to evaluate what criteria exist to diagnose small-vessel vasculitis and common mimics. This paper presents the existing criteria of small-vessel vasculitis conditions and mimics them to guide the future integration of AI/ML algorithms to aid in diagnosing these conditions, which present similarly and non-specifically.

Gender disparity between authors in leading medical journals during the COVID-19 pandemic: a cross-sectional review.

OBJECTIVES: Evaluate gender differences in authorship of COVID-19 articles in high-impact medical journals compared with other topics. DESIGN: Cross-sectional review. DATA SOURCES: Medline database. ELIGIBILITY CRITERIA: Articles published from 1 January to 31 December 2020 in the seven leading general medical journals by impact factor. Article types included primary research, reviews, editorials and commentaries. DATA EXTRACTION: Key data elements were whether the study topic was related to COVID-19 and names of the principal and the senior authors. A hierarchical approach was used to determine the likely gender of authors. Logistic regression assessed the association of study characteristics, including COVID-19 status, with authors' likely gender; this was quantified using adjusted ORs (aORs). RESULTS: We included 2252 articles, of which 748 (33.2%) were COVID-19-related and 1504 (66.8%) covered other topics. A likely gender was determined for 2138 (94.9%) principal authors and 1890 (83.9%) senior authors. Men were significantly more likely to be both principal (1364 men; 63.8%) and senior (1332 men; 70.5%) authors. COVID-19-related articles were not associated with the odds of men being principal (aOR 0.99; 95% CI 0.81 to 1.21; p=0.89) or senior authors (aOR 0.96; 95% CI 0.78 to 1.19; p=0.71) relative to other topics. Articles with men as senior authors were more likely to have men as principal authors (aOR 1.49; 95% CI 1.21 to 1.83; p<0.001). Men were more likely to author articles reporting original research and those with corresponding authors based outside the USA and Europe. CONCLUSIONS: Women were substantially under-represented as authors among articles in leading medical journals; this was not significantly different for COVID-19-related articles. Study limitations include potential for misclassification bias due to the name-based analysis. Results suggest that barriers to women's authorship in high-impact journals during COVID-19 are not significantly larger than barriers that preceded the pandemic and that are likely to continue beyond it. PROSPERO REGISTRATION NUMBER: CRD42020186702.

Drosophila Nedd4-long reduces Amphiphysin levels in muscles and leads to impaired T-tubule formation.

Drosophila Nedd4 (dNedd4) is a HECT ubiquitin ligase with two main splice isoforms: dNedd4-short (dNedd4S) and -long (dNedd4Lo). DNedd4Lo has a unique N-terminus containing a Pro-rich region. We previously showed that whereas dNedd4S promotes neuromuscular synaptogenesis, dNedd4Lo inhibits it and impairs larval locomotion. To delineate the cause of the impaired locomotion, we searched for binding partners to the N-terminal unique region of dNedd4Lo in larval lysates using mass spectrometry and identified Amphiphysin (dAmph). dAmph is a postsynaptic protein containing SH3-BAR domains and regulates muscle transverse tubule (T-tubule) formation in flies. We validated the interaction by coimmunoprecipitation and showed direct binding between dAmph-SH3 domain and dNedd4Lo N-terminus. Accordingly, dNedd4Lo was colocalized with dAmph postsynaptically and at muscle T-tubules. Moreover, expression of dNedd4Lo in muscle during embryonic development led to disappearance of dAmph and impaired T-tubule formation, phenocopying amph-null mutants. This effect was not seen in muscles expressing dNedd4S or a catalytically-inactive dNedd4Lo(C→A). We propose that dNedd4Lo destabilizes dAmph in muscles, leading to impaired T-tubule formation and muscle function.

Enzyme linked immuno mass spectrometric assay (ELIMSA).

A new technology termed ELIMSA combines the specificity and enzymatic amplification of Enzyme Linked Immunosorbent assay (ELISA) with the sensitivity and flexibility of mass spectrometry (MS). At present, substrates for the reporter enzymes horseradish peroxidase (HRP) or alkaline phosphatase (AP) yield colored, fluorescent or luminescent products. The central concept of ELIMSA is that the reporter enzymes HRP and AP yield products that ionize efficiently with a high signal to noise ratio that can be measured by mass spectrometry. The reporter enzymes HRP or AP may be covalently attached to a specific detection probe such as a protein or an antibody to bind their target analyte and then catalyze the rapid production of ionizable, small-molecules. The use of mass spectrometry to measure small molecule products may commonly reach femto to picomol amounts on the column with high signal to noise ratio. Mass spectrometry combined with the enzyme amplification in ELISA provides absolute sensitivity to detect attomol of PSA and was comparable to, or more sensitive, than radio immune assays and electrochemical detectors but with only existing reagents and equipment. ELIMSA permits monitoring of multiple substrates and products and provides comparison to absolute standards. BIOLOGICAL SIGNIFICANCE: There is an urgent need to detect and quantify low abundance proteins such as hormones, chemokines, cytokines, and others that exist at attomolar concentrations under physiological conditions by ELIMSA. A sensitive method for the quantification of immunological assays is obtained by applying mass spectrometry to detect the products of the alkaline phosphatase (AP) and horseradish peroxidase (HRP) enzyme reactions. There are many molecules from human subjects or micro-organisms that are of great importance to medicine, industry, nutrition or the environment that need to be repeatedly analyzed and are often near to, or beyond, the edge of existing analytical technology. The presence of molecules in biological samples, industrial products or the environment may be detected by probes that bind to the target analyte. Combining the reporter enzymes from ELISA with sensitive liquid chromatography (LC), electrospray ionization (ESI) and tandem mass spectrometry (MS/MS) will permit the sensitive detection and quantification of the molecular probes by Enzyme Linked Immuno Mass Spectrometric Assay (ELIMSA). The flexibility and sensitivity of mass spectrometry to measure large numbers of compounds simultaneously should permit the quantification of multiple ELIMSA reactions at separate mass-to-charge (m/z) ratios. Hence ELIMSA and it variants should permit the rapid and simple detection and quantification of many molecules over the complete range of biologically important concentrations without the use of radiolabels using only existing antibodies, reagents and instruments. Antibodies coupled to reporter enzymes that are widely used in biomedical and environmental applications can now be detected and quantified using ultra sensitive mass spectrometry to create a sensitive and flexible ELIMSA system. Absolute standards of analytes or enzyme product may serve as a reference.

Tyrosine phosphorylation of NEDD4 activates its ubiquitin ligase activity.

Ligand binding to the receptor tyrosine kinase fibroblast growth factor (FGF) receptor 1 (FGFR1) causes dimerization and activation by transphosphorylation of tyrosine residues in the kinase domain. FGFR1 is ubiquitylated by the E3 ligase NEDD4 (also known as NEDD4-1), which promotes FGFR1 internalization and degradation. Although phosphorylation of FGFR1 is required for NEDD4-dependent endocytosis, NEDD4 directly binds to a nonphosphorylated region of FGFR1. We found that activation of FGFR1 led to activation of c-Src kinase-dependent tyrosine phosphorylation of NEDD4, enhancing the ubiquitin ligase activity of NEDD4. Using mass spectrometry, we identified several FGF-dependent phosphorylated tyrosines in NEDD4, including Tyr(43) in the C2 domain and Tyr(585) in the HECT domain. Mutating these tyrosines to phenylalanine to prevent phosphorylation inhibited FGF-dependent NEDD4 activity and FGFR1 endocytosis and enhanced cell proliferation. Mutating the tyrosines to glutamic acid to mimic phosphorylation enhanced NEDD4 activity. Moreover, the NEDD4 C2 domain bound the HECT domain, and the presence of phosphomimetic mutations inhibited this interaction, suggesting that phosphorylation of NEDD4 relieves an inhibitory intra- or intermolecular interaction. Accordingly, activation of FGFR1 was not required for activation of NEDD4 that lacked its C2 domain. Activation of c-Src by epidermal growth factor (EGF) also promoted tyrosine phosphorylation and enhanced the activity of NEDD4. Thus, we identified a feedback mechanism by which receptor tyrosine kinases promote catalytic activation of NEDD4 and that may represent a mechanism of receptor crosstalk.