Abstract
Hyper-activation of extracellular signal-regulated kinase (ERK) 1/2 contributes to heart dysfunction in cardiomyopathy caused by mutations in the lamin A/C gene (LMNA cardiomyopathy). The ...mechanism of how this affects cardiac function is unknown. We show that active phosphorylated ERK1/2 directly binds to and catalyzes the phosphorylation of the actin depolymerizing factor cofilin-1 on Thr25. Cofilin-1 becomes active and disassembles actin filaments in a large array of cellular and animal models of LMNA cardiomyopathy. In vivo expression of cofilin-1, phosphorylated on Thr25 by endogenous ERK1/2 signaling, leads to alterations in left ventricular function and cardiac actin. These results demonstrate a novel role for cofilin-1 on actin dynamics in cardiac muscle and provide a rationale on how increased ERK1/2 signaling leads to LMNA cardiomyopathy.
The human extracellular matrix glycoprotein fibrillin-1 is the primary component of the 10- to 12-nm-diameter microfibrils, which perform key structural and regulatory roles in connective tissues. ...Relatively little is known about the molecular mechanisms of fibrillin assembly into microfibrils. Studies using recombinant fibrillin fragments indicate that an interaction between the N- and C-terminal regions drives head-to-tail assembly. Here, we present the structure of a fibrillin N-terminal fragment comprising the fibrillin unique N-terminal (FUN) and the first three epidermal growth factor (EGF)-like domains (FUN-EGF3). Two rod-like domain pairs are separated by a short, flexible linker between the EGF1 and EGF2 domains. We also show that the binding site for the C-terminal region spans multiple domains and overlaps with a heparin interaction site. These data suggest that heparan sulfate may sequester fibrillin at the cell surface via FUN-EGF3 prior to aggregation of the C terminus, thereby regulating microfibril assembly.
•The fibrillin unique N-terminal (FUN) domain adopts a novel fold•The binding site for the fibrillin C terminus spans multiple domains•The heparin interaction site overlaps with the C-terminal binding region•Detailed molecular insights into an interaction between fibrillin molecules
Fibrillin microfibrils are key structural and regulatory components of connective tissue, but their assembly is poorly understood. Yadin et al. report a structure of the fibrillin N-terminal domains and propose that heparan sulphate regulates end-to-end assembly.
Single-molecule FRET (smFRET) has long been used as a molecular ruler for the study of biology on the nanoscale (∼2–10 nm); smFRET in total-internal reflection fluorescence (TIRF) Förster resonance ...energy transfer (TIRF-FRET) microscopy allows multiple biomolecules to be simultaneously studied with high temporal and spatial resolution. To operate at the limits of resolution of the technique, it is essential to investigate and rigorously quantify the major sources of noise and error; we used theoretical predictions, simulations, advanced image analysis, and detailed characterization of DNA standards to quantify the limits of TIRF-FRET resolution. We present a theoretical description of the major sources of noise, which was in excellent agreement with results for short-timescale smFRET measurements (<200 ms) on individual molecules (as opposed to measurements on an ensemble of single molecules). For longer timescales (>200 ms) on individual molecules, and for FRET distributions obtained from an ensemble of single molecules, we observed significant broadening beyond theoretical predictions; we investigated the causes of this broadening. For measurements on individual molecules, analysis of the experimental noise allows us to predict a maximum resolution of a FRET change of 0.08 with 20-ms temporal resolution, sufficient to directly resolve distance differences equivalent to one DNA basepair separation (0.34 nm). For measurements on ensembles of single molecules, we demonstrate resolution of distance differences of one basepair with 1000-ms temporal resolution, and differences of two basepairs with 80-ms temporal resolution. Our work paves the way for ultra-high-resolution TIRF-FRET studies on many biomolecules, including DNA processing machinery (DNA and RNA polymerases, helicases, etc.), the mechanisms of which are often characterized by distance changes on the scale of one DNA basepair.
Abstract Immunoglobulins (Ig), which exist either as B-cell receptors (BCR) on the surface of B cells or as antibodies when secreted, play a key role in the recognition and response to antigenic ...threats. The capability to jointly characterize the BCR and antibody repertoire is crucial for understanding human adaptive immunity. From peripheral blood, bulk BCR sequencing (bulkBCR-seq) currently provides the highest sampling depth, single-cell BCR sequencing (scBCR-seq) allows for paired chain characterization, and antibody peptide sequencing by tandem mass spectrometry (Ab-seq) provides information on the composition of secreted antibodies in the serum. Yet, it has not been benchmarked to what extent the datasets generated by these three technologies overlap and complement each other. To address this question, we isolated peripheral blood B cells from healthy human donors and sequenced BCRs at bulk and single-cell levels, in addition to utilizing publicly available sequencing data. Integrated analysis was performed on these datasets, resolved by replicates and across individuals. Simultaneously, serum antibodies were isolated, digested with multiple proteases, and analyzed with Ab-seq. Systems immunology analysis showed high concordance in repertoire features between bulk and scBCR-seq within individuals, especially when replicates were utilized. In addition, Ab-seq identified clonotype-specific peptides using both bulk and scBCR-seq library references, demonstrating the feasibility of combining scBCR-seq and Ab-seq for reconstructing paired-chain Ig sequences from the serum antibody repertoire. Collectively, our work serves as a proof-of-principle for combining bulk sequencing, single-cell sequencing, and mass spectrometry as complementary methods towards capturing humoral immunity in its entirety.
The technical objective of total knee arthroplasty (TKA) is to restore normal mechanical parameters to the knee. Patient-specific instrumentation (PSI) was developed to streamline the operative ...process and improve accuracy. PSI produces individualized cutting guides based on three-dimensional models of the patient's anatomy acquired from computed-tomography (CT) or magnetic-resonance imaging (MRI). However, the superiority of one modality over the other remains unclear. Therefore, we aimed to compare the accuracy of patient-specific cutting guides produced from MRI or CT imaging methods in TKA.
Electronic databases were systematically searched using relevant keywords and MeSH terms for original-data English-language publications comparing the accuracy of CT and MRI-based PSI cutting guides in TKA. Data was extracted from the text, tables and figures of studies and meta-analysed.
MRI-based PSI cutting guides produced a lower proportion of coronal plane outliers (>3°) with regard to overall limb mechanical axis (OR 2.75, p = 0.01). There were no significant differences between the two in terms of sagittal femoral and tibial component placement, or coronal femoral and tibial placement, or femoral component axial rotation. Tibial rotation was not analysed in the literature.
MRI-based patient-specific cutting guides produced a lower proportion of outliers in the overall coronal alignment of the limb compared to CT, with no significant difference between the two in terms of femoral or tibial component placement. Future studies should investigate the differences in resource usage and operative time between the two to inform surgeons' decision making when choosing an ideal imaging modality for PSI TKA.
Meta-analysis.
III, systematic review of cohort and comparative studies.
Abstract Introduction Venous thromboembolism (VTE) comprises pulmonary embolism (PE) and deep vein thrombosis (DVT), and is a complication of particular concern in lower limb arthroplasty. In recent ...years, aspirin has emerged as a potential alternative thromboprophylactic agent, particularly following its acceptance as a recommended agent by the American College of Chest Physicians (ACCP). Aspirin is favourable due to its relative cost-effectiveness and convenience compared to novel oral anticoagulants and warfarin. However, its efficacy since its inclusion in the ACCP guidelines remains unclear. The present systematic review aimed to establish the efficacy of aspirin in preventing VTE in total hip and knee arthroplasty. Methods Electronic searches were performed using six databases from up to June 2015, identifying all relevant studies. Data were extracted and meta-analysed. Results Eleven relevant studies were identified for inclusion in the present meta-analysis. The overall rate of DVT and PE in both hip and knee arthroplasty was 1.2% and 0.6%, respectively. The rate of major bleeding was 0.3%. Pooled mortality rate was 0.2%. All findings demonstrated a high and significant degree of heterogeneity. Conclusions Aspirin, both alone and in multimodal approaches to thromboprophylaxis, confers a low rate of VTE, with a low risk of major bleeding complications. However, the evidence for its use is limited by the low quality of studies and variation in dose in dosing regimes. Future randomised controlled trials should investigate the efficacy of aspirin, as well as the ideal dosing protocol for its use in thromboprophylaxis in arthroplasty.
The intersection of technological changes and societal evolution has transformed every aspect of human life. Technological advancements are transforming how healthcare knowledge is expanding and ...accelerating the outreach of critical medical services delivery (Jamal et al. in Health Information Management Journal 38(3):26–37,
2009
). While this transformation facilitates new opportunities simultaneously it also introduces challenges (Jacobzone and Oxley,
2001
). Appropriate Health Technology (HT) is vital to new and existing global health care programs. Therefore, qualified professionals who can safely guide the development, evaluation, installation, integration, performance assurance, and risk mitigation of HT must be in position to lead. Trained Clinical Engineers (CE) and Biomedical Engineers (BE) have been recognized by the World Health Organization (WHO) as the essential practitioners to providing this critically needed guidance. Over the past four years, a senior professional group participated in an international project that seeks evidence for the hypothesis - that the engagement of CE and BE in guiding HT - impacts positively on patient outcomes, while the alternative is that there is no difference. The group collected published data that was subjected to peer review screening; additional data qualification conditions are described in this paper. The project was initiated at the Global CE Summit during the first International Clinical Engineering and Health Technology Management Congress (ICEHTMC) in Hangzhou, China in October 2015 (Global Clinical Engineering Summit at the First International Clinical Engineering and Health Technology Management Congress,
2015
). Following the adoption of a resolution to investigate CE contributions to the improvement of world health status, an international survey and literature survey were initiated. During the first two years of this project 150 case studies from 90 countries were identified covering the previous ten years. The results of this survey were presented to health leaders at the World Health Organization (WHO) World Health Assembly in 2016. Last year, 250 case studies were added including 35 more countries covering the 2016–2017 period. The combined project contains 400 qualified submissions from 125 countries. The conclusion was that engagement of CE and BME is critical for successful investment in HT and for achieving intended patient outcomes. This paper describes the project’s plan, the results of the literature review performed, and the evidence identified during the process.
Healthcare services and technology are in a dependent relationship that is at all time high with every indicator suggesting further future increase of this trend. Many topics are discussed, including ...the quality of patient care, clinical decision support systems, disaster preparedness, computerized management systems, and more. Hossain MA, Ahmad M, Islam MR, David Y (2019) Mathematical modeling of clinical engineering approach to evaluate the quality of patient care.
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