Preoperative single high-dose glucocorticoid may have early outcome benefits in total hip arthroplasty (THA) and knee arthroplasty (TKA), but long-term safety aspects have not been evaluated.
From ...October 2013, the departments reporting to the prospective Lundbeck Foundation Database for Fast-track Hip and Knee Replacement introduced preoperative methylprednisolone (MP) 125 mg as part of a multimodal analgesic protocol in TKA. We analysed the risk of length of hospital stay (LOS) >4 days, 30 and 90 day readmissions in patients with MP vs patients having TKA before the use of MP and adjusted for comorbidity and place of surgery. An unadjusted comparison was specifically done to evaluate deep prosthetic infections.
Of a total of 3927 TKA procedures, 1442 received MP. Median LOS was 2 days in both groups, but the fraction with LOS >4 days was 6.0% vs 11.5% (P<0.001) in patients with MP vs those without, and with a reduced risk of LOS >4 days in adjusted analysis odds ratio (OR) 0.51; confidence interval (CI) 0.39–0.68; P<0.001. Readmission rates were 5.6% (CI 4.5–6.9) vs 4.4% (P=0.095) and 7.8% vs 7.3% (P=0.53) at 30 and 90 days with and without MP, respectively.
Adjusted analysis did not identify MP to be associated with 30 day (OR 1.18; CI 0.89–1.56; P=0.25) or 90 day (OR 1.12; CI 0.86–1.46; P=0.39) readmissions. The incidence of deep infections requiring surgical intervention was 0.8% vs 0.7% with MP vs without, respectively (P=0.78).
In this detailed prospective cohort study, preoperative high-dose glucocorticoid administration was not associated with LOS >4 days, readmissions or infectious complications in TKA patients without contraindications.
NCT01515670.
Introduction
Limited data exist on patient safety after simultaneous vs staged bilateral total knee arthroplasty (TKA) in matched groups. Hence, the aim of this study was to compare length of stay ...(LOS), in-hospital complications, 30-day readmissions and mortality after simultaneous and staged bilateral TKA in matched patients.
Patients and methods
A retrospective case–control study of prospectively collected data in nine centres from February 2010 to November 2015. Propensity scores (PS) were used to match simultaneous and staged (1–6 months between stages) bilateral TKA patients with prospectively collected patient characteristics from the Lundbeck Foundation Centre for Fast-track THA and TKA Database. 30-day follow-up was acquired from the Danish Patient Registry and patient records.
Results
A total of 344 (47.1%) simultaneous and 386 (52.9%) staged bilateral TKA procedures were performed. PS matching was possible in 232 simultaneous and 232 staged bilateral TKA patients. LOS was median 4 days (IQR 3–5) after simultaneous and cumulated 4 days (IQR 4–6) after staged procedures. The in-hospital complication rate was 15.5% after simultaneous vs 7.3% (
p
= 0.004) after staged procedures. Two cases (0.9%) of venous thromboembolic events were found in each group. Eight patients (3.4%) were re-operated after simultaneous vs one patient (0.4%) after staged bilateral TKA (
p
= 0.037). The 30-day readmission rate was 8.6% after simultaneous vs 5.6% after staged procedures (
p
= 0.281). No patients died in either group.
Conclusions
We found no significant differences in 30-day readmission rates and mortality between simultaneous and staged bilateral TKA, but the in-hospital complication rate and re-operation rate was higher after the simultaneous procedure calling for further matched investigations in larger cohorts.
Proteolytic processing shapes cellular interactions with the environment. As a pathway of unconventional protein secretion, ectodomain shedding releases soluble proteoforms of membrane-anchored ...proteins. This can trigger subsequent cleavage within the membrane stub and the release of additional soluble fragments to intra- and extracellular environments. Distinct membrane-bound proteases, or sheddases, may cleave the same membrane proteins at different sites. Determination of these precise cleavage sites is important, as differently processed proteoforms may exhibit distinct physiological properties and execute antagonistic paracrine and endocrine signaling functions. Conventional quantitative proteomic approaches reliably identify shed proteoforms, but typically not their termini and are thus not able distinguish between functionally different proteoforms differing only by a few amino acids. Dedicated positional proteomics overcomes this challenge and enables proteome-wide identification of protein N- and C-termini. Here, we review positional proteomics techniques, summarize their application to ectodomain shedding and discuss current challenges and developments.
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•Proteolytic processing of membrane proteins releases new soluble proteoforms.•These unconventionally secreted proteoforms have important signaling functions.•Differentially processed proteoforms are defined by their N- and C-termini.•Termini enrichment enables proteome-wide characterization of these proteoforms.
We review methods enabling proteome-wide characterization of protein termini, which have already provided new insights into proteolytic processes, alternative translation, and N-terminal ...modifications and determinants of protein stability in plants.
Abstract
Dynamic regulation of protein function and abundance plays an important role in virtually every aspect of plant life. Diversifying mechanisms at the RNA and protein level result in many protein molecules with distinct sequence and modification, termed proteoforms, arising from a single gene. Distinct protein termini define proteoforms arising from translation of alternative transcripts, use of alternative translation initiation sites, and different co- and post-translational modifications of the protein termini. Also site-specific proteolytic processing by endo- and exoproteases generates truncated proteoforms, defined by distinct protease-generated neo-N- and neo-C-termini, that may exhibit altered activity, function, and localization compared with their precursor proteins. In eukaryotes, the N-degron pathway targets cytosolic proteins, exposing destabilizing N-terminal amino acids and/or destabilizing N-terminal modifications for proteasomal degradation. This enables rapid and selective removal not only of unfolded proteins, but also of substrate proteoforms generated by proteolytic processing or changes in N-terminal modifications. Here we summarize current protocols enabling proteome-wide analysis of protein termini, which have provided important new insights into N-terminal modifications and protein stability determinants, protein maturation pathways, and protease–substrate relationships in plants.
Multidrug resistant (MDR) bacteria have adapted to most clinical antibiotics and are a growing threat to human health. One promising type of candidates for the everlasting demand of new antibiotic ...compounds constitute antimicrobial peptides (AMPs). These peptides act against different types of microbes by permeabilizing pathogen cell membranes, whereas being harmless to mammalian cells. Contrarily, another class of membrane-active peptides, namely cell-penetrating peptides (CPPs), is known to translocate in eukaryotic cells without substantially affecting the cell membrane. Since CPPs and AMPs share several physicochemical characteristics, we hypothesized if we can rationally direct the activity of a CPP towards antimicrobial activity. Herein, we describe the screening of a synthetic library, based on the CPP sC18, including structure-based design to identify the active residues within a CPP sequence and to discover novel AMPs with high activity. Peptides with increased hydrophobicity were tested against various bacterial strains, and hits were further optimized leading to four generations of peptides, with the last also comprising fluorinated amino acid building blocks. Interestingly, beside strong antibacterial activities, we also detected activity in cancer cells, while non-cancerous cells remained unharmed. The results highlight our new candidates, particularly those from generation 4, as a valuable and promising source for the development of future therapeutics with antibacterial activity and beyond.
Fungalysins from several phytopathogenic fungi have been shown to be involved in cleavage of plant chitinases. While fungal chitinases are responsible for cell wall remodeling during growth and ...morphogenesis, plant chitinases are important components of immunity. This study describes a dual function of the Ustilago maydis fungalysin UmFly1 in modulation of both plant and fungal chitinases.
Genetic, biochemical and microscopic experiments were performed to elucidate the in vitro and in planta functions of U. maydis UmFly1.
U. maydis Δumfly1 mutants show significantly reduced virulence, which coincides with reduced cleavage of the maize chitinase ZmChiA within its chitin-binding domain. Moreover, deletion of umfly1 affected the cell separation of haploid U. maydis sporidia. This phenotype is associated with posttranslational activation of the endogenous chitinase UmCts1. Genetic complementation of the Δumfly1 mutant with a homologous gene from closely related, but nonpathogenic, yeast fully rescued the cell separation defect in vitro, but it could not recover the Δumfly1 defect in virulence and cleavage of the maize chitinase.
We report on the dual function of the secreted fungalysin UmFly1. We hypothesize that co-evolution of U. maydis with its host plant extended the endogenous function of UmFly1 towards the modulation of plant chitinase activity to promote infection.
Glucose and glutamine are the two principal nutrients that cancer cells use to proliferate and survive. Many cancers show altered glucose metabolism, which constitutes the basis for in vivo positron ...emission tomography (PET) imaging with (18)F-fluorodeoxyglucose ((18)F-FDG). However, (18)F-FDG is ineffective in evaluating gliomas because of high background uptake in the brain. Glutamine metabolism is also altered in many cancers, and we demonstrate that PET imaging in vivo with the glutamine analog 4-(18)F-(2S,4R)-fluoroglutamine ((18)F-FGln) shows high uptake in gliomas but low background brain uptake, facilitating clear tumor delineation. Chemo/radiation therapy reduced (18)F-FGln tumor avidity, corresponding with decreased tumor burden. (18)F-FGln uptake was not observed in animals with a permeable blood-brain barrier or neuroinflammation. We translated these findings to human subjects, where (18)F-FGln showed high tumor/background ratios with minimal uptake in the surrounding brain in human glioma patients with progressive disease. These data suggest that (18)F-FGln is avidly taken up by gliomas, can be used to assess metabolic nutrient uptake in gliomas in vivo, and may serve as a valuable tool in the clinical management of gliomas.
The inability to visualize the true extent of cancers represents a significant challenge in many areas of oncology. The margins of most cancer types are not well demarcated because the cancer ...diffusely infiltrates the surrounding tissues. Furthermore, cancers may be multifocal and characterized by the presence of microscopic satellite lesions. Such microscopic foci represent a major reason for persistence of cancer, local recurrences, and metastatic spread, and are usually impossible to visualize with currently available imaging technologies. An imaging method to reveal the true extent of tumors is desired clinically and surgically. We show the precise visualization of tumor margins, microscopic tumor invasion, and multifocal locoregional tumor spread using a new generation of surface-enhanced resonance Raman scattering (SERRS) nanoparticles, which are termed SERRS nanostars. The SERRS nanostars feature a star-shaped gold core, a Raman reporter resonant in the near-infrared spectrum, and a primer-free silication method. In genetically engineered mouse models of pancreatic cancer, breast cancer, prostate cancer, and sarcoma, and in one human sarcoma xenograft model, SERRS nanostars enabled accurate detection of macroscopic malignant lesions, as well as microscopic disease, without the need for a targeting moiety. Moreover, the sensitivity (1.5 fM limit of detection) of SERRS nanostars allowed imaging of premalignant lesions of pancreatic and prostatic neoplasias. High sensitivity and broad applicability, in conjunction with their inert gold-silica composition, render SERRS nanostars a promising imaging agent for more precise cancer imaging and resection.
As proteome-wide C-terminal sequence analysis has been largely intractable, we developed a polymer-based enrichment approach to profile protein C-terminal peptides by mass spectrometry and identified ...hundreds of C-terminal peptides in the Escherichia coli proteome. We isotopically labeled GluC protease-digested and undigested samples and identified GluC substrates and their cleavage sites by quantification of neo-C-terminal peptides. Our method thus enables global annotation of protein C-terminal posttranslational modifications, including proteolytic truncations.
Mitochondrial proteases constitute a fundamental part of the organellar protein quality control system to ensure the timely removal of damaged or obsolete proteins. The analysis of proteases is often ...limited to the identification of bona fide substrates that are degraded in the presence and become more abundant in the absence of the respective protease. However, proteases in numerous organisms from bacteria to humans can process specific substrates to release shortened proteins with potentially altered activities. Here, we describe an adaptation of the substrate-trapping approach, as well as the N-terminal profiling protocol Terminal Amine Isotope Labeling of Substrates (TAILS) for the identification of bona fide substrates and mitochondrial proteins that undergo complete or partial proteolysis.
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