Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 140
Filtrar
1.
J Biol Chem ; 298(2): 101514, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34929165

RESUMO

Recognition of human autophagy-related 8 (hATG8) proteins by autophagy receptors represents a critical step within this cellular quality control system. Autophagy impairment is known to be a pathogenic mechanism in the motor neuron disorder amyotrophic lateral sclerosis (ALS). Overlapping but specific roles of hATG8 proteins belonging to the LC3 and GABARAP subfamilies are incompletely understood, and binding selectivity is typically overlooked. We previously showed that an ALS-associated variant of the SQSTM1/p62 (p62) autophagy receptor bearing an L341V mutation within its ATG8-interacting motif (AIM) impairs recognition of LC3B in vitro, yielding an autophagy-deficient phenotype. Improvements in understanding of hATG8 recognition by AIMs now distinguish LC3-interaction and GABARAP-interaction motifs and predict the effects of L341V substitution may extend beyond loss of function to biasing AIM binding preference. Through biophysical analyses, we confirm impaired binding of the L341V-AIM mutant to LC3A, LC3B, GABARAP, and GABARAPL1. In contrast, p62 AIM interactions with LC3C and GABARAPL2 are unaffected by this mutation. Isothermal titration calorimetry and NMR investigations provided insights into the entropy-driven GABARAPL2/p62 interaction and how the L341V mutation may be tolerated. Competition binding demonstrated reduced association of the L341V-AIM with one hATG8 manifests as a relative increase in association with alternate hATG8s, indicating effective reprogramming of hATG8 selectivity. These data highlight how a single AIM peptide might compete for binding with different hATG8s and suggest that the L341V-AIM mutation may be neomorphic, representative of a disease mechanism that likely extends into other human disorders.


Assuntos
Esclerose Lateral Amiotrófica , Família da Proteína 8 Relacionada à Autofagia , Proteína Sequestossoma-1 , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Proteínas Reguladoras de Apoptose/metabolismo , Autofagia/fisiologia , Família da Proteína 8 Relacionada à Autofagia/metabolismo , Proteínas Relacionadas à Autofagia/metabolismo , Humanos , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína Sequestossoma-1/genética , Proteína Sequestossoma-1/metabolismo
2.
BMC Med Res Methodol ; 23(1): 234, 2023 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-37838681

RESUMO

BACKGROUND: The COVID-19 pandemic resulted in major disruption to healthcare delivery worldwide causing medical services to adapt their standard practices. Learning how these adaptations result in unintended patient harm is essential to mitigate against future incidents. Incident reporting and learning system data can be used to identify areas to improve patient safety. A classification system is required to make sense of such data to identify learning and priorities for further in-depth investigation. The Patient Safety (PISA) classification system was created for this purpose, but it is not known if classification systems are sufficient to capture novel safety concepts arising from crises like the pandemic. We aimed to review the application of the PISA classification system during the COVID-19 pandemic to appraise whether modifications were required to maintain its meaningful use for the pandemic context. METHODS: We conducted a mixed-methods study integrating two phases in an exploratory, sequential design. This included a comparative secondary analysis of patient safety incident reports from two studies conducted during the first wave of the pandemic, where we coded patient-reported incidents from the UK and clinician-reported incidents from France. The findings were presented to a focus group of experts in classification systems and patient safety, and a thematic analysis was conducted on the resultant transcript. RESULTS: We identified five key themes derived from the data analysis and expert group discussion. These included capitalising on the unique perspective of safety concerns from different groups, that existing frameworks do identify priority areas to investigate further, the objectives of a study shape the data interpretation, the pandemic spotlighted long-standing patient concerns, and the time period in which data are collected offers valuable context to aid explanation. The group consensus was that no COVID-19-specific codes were warranted, and the PISA classification system was fit for purpose. CONCLUSIONS: We have scrutinised the meaningful use of the PISA classification system's application during a period of systemic healthcare constraint, the COVID-19 pandemic. Despite these constraints, we found the framework can be successfully applied to incident reports to enable deductive analysis, identify areas for further enquiry and thus support organisational learning. No new or amended codes were warranted. Organisations and investigators can use our findings when reviewing their own classification systems.


Assuntos
COVID-19 , Segurança do Paciente , Humanos , Pandemias , Erros Médicos , COVID-19/epidemiologia , Gestão de Riscos
3.
Int J Mol Sci ; 24(8)2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37108653

RESUMO

For biomedical applications, gelatin is usually modified with methacryloyl groups to obtain gelatin methacryloyl (GelMA), which can be crosslinked by a radical reaction induced by low wavelength light to form mechanically stable hydrogels. The potential of GelMA hydrogels for tissue engineering has been well established, however, one of the main disadvantages of mammalian-origin gelatins is that their sol-gel transitions are close to room temperature, resulting in significant variations in viscosity that can be a problem for biofabrication applications. For these applications, cold-water fish-derived gelatins, such as salmon gelatin, are a good alternative due to their lower viscosity, viscoelastic and mechanical properties, as well as lower sol-gel transition temperatures, when compared with mammalian gelatins. However, information regarding GelMA (with special focus on salmon GelMA as a model for cold-water species) molecular conformation and the effect of pH prior to crosslinking, which is key for fabrication purposes since it will determine final hydrogel's structure, remains scarce. The aim of this work is to characterize salmon gelatin (SGel) and salmon methacryloyl gelatin (SGelMA) molecular configuration at two different acidic pHs (3.6 and 4.8) and to compare them to commercial porcine gelatin (PGel) and methacryloyl porcine gelatin (PGelMA), usually used for biomedical applications. Specifically, we evaluated gelatin and GelMA samples' molecular weight, isoelectric point (IEP), their molecular configuration by circular dichroism (CD), and determined their rheological and thermophysical properties. Results showed that functionalization affected gelatin molecular weight and IEP. Additionally, functionalization and pH affected gelatin molecular structure and rheological and thermal properties. Interestingly, the SGel and SGelMA molecular structure was more sensitive to pH changes, showing differences in gelation temperatures and triple helix formation than PGelMA. This work suggests that SGelMA presents high tunability as a biomaterial for biofabrication, highlighting the importance of a proper GelMA molecular configuration characterization prior to hydrogel fabrication.


Assuntos
Gelatina , Engenharia Tecidual , Animais , Gelatina/química , Temperatura de Transição , Viscosidade , Suspensões , Engenharia Tecidual/métodos , Metacrilatos/química , Salmão , Hidrogéis/química , Conformação Molecular , Água , Mamíferos
4.
J Vis Commun Med ; 46(3): 160-167, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37943515

RESUMO

ENT is a consistently under-represented specialty in medical school curricula. With social distancing measures limiting face-to-face (FtF) teaching and clinical opportunities, we created an e-Learning platform to consolidate and improve knowledge on common ENT emergencies. Following invitation to medical students undergoing their rotation in ENT at University Hospital Wales (UHW) Cardiff, five focus groups were shown an e-Learning module and interviewed between June and July 2021. 13 medical students participated in total (9 female, 4 male, median age 22 years). These structured interviews were recorded and transcribed. Transcripts were analysed using the qualitative data analysis software NVivo (QSR International, UK). The modules were found to be concise, clinically relevant and beneficial to student confidence in recognising and managing ENT emergencies. While e-Learning will likely never replace face-to-face learning, it was perceived to be a beneficial resource both academically and practically- especially in the context of limited clinical opportunities.


Assuntos
Instrução por Computador , Otolaringologia , Estudantes de Medicina , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Emergências , Otolaringologia/educação , Currículo
5.
Metabolomics ; 18(2): 13, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-35141784

RESUMO

BACKGROUND: The paternal diet affects lipid metabolism in offspring for at least two generations through nutritional programming. However, we do not know how this is propagated to the offspring. OBJECTIVES: We tested the hypothesis that the changes in lipid metabolism that are driven by paternal diet are propagated through spermatozoa and not seminal plasma. METHODS: We applied an updated, purpose-built computational network analysis tool to characterise control of lipid metabolism systemically (Lipid Traffic Analysis v2.3) on a known mouse model of paternal nutritional programming. RESULTS: The analysis showed that the two possible routes for programming effects, the sperm (genes) and seminal plasma (influence on the uterine environment), both have a distinct effect on the offspring's lipid metabolism. Further, the programming effects in offspring suggest that changes in lipid distribution are more important than alterations in lipid biosynthesis. CONCLUSIONS: These results show how the uterine environment and genes both affect lipid metabolism in offspring, enhancing our understanding of the link between parental diet and metabolism in offspring.


Assuntos
Metabolismo dos Lipídeos , Sêmen , Animais , Pai , Humanos , Masculino , Metabolômica , Camundongos , Espermatozoides/metabolismo
6.
Nucleic Acids Res ; 48(8): 4179-4194, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32182342

RESUMO

Abnormal DUX4 expression in skeletal muscles plays a key role in facioscapulohumeral muscular dystrophy (FSHD) pathogenesis, although the molecular mechanisms regulating DUX4 expression are not fully defined. Using bioinformatic analysis of the genomic DUX4 locus, we have identified a number of putative G-quadruplexes (GQs) forming sequences. Their presence was confirmed in synthetic oligonucleotiode sequences derived from the enhancer, promoter and transcript of DUX4 through circular dichroism and nuclear magnetic resonance analysis. We further examined the binding affinity of a naturally occurring GQ stabilizing compound, berberine, to these non-canonical genetic structures using UV-Vis and fluorescence spectroscopy. Subsequent in vitro study in FSHD patient myoblasts indicated that berberine treatment reduced DUX4 expression and also expression of genes normally switched on by DUX4. Further investigation in a mouse model overexpressing exogenous DUX4 confirmed the therapeutic effects of berberine in downregulating DUX4 protein expression, inhibiting muscle fibrosis, and consequently rescuing muscle function. Our data demonstrate for the first time that GQs are present in the DUX4 locus and that the GQ interactive ligand reduces DUX4 expression suggesting potential role of GQs in FSHD pathogenesis. Our work provides the basis of a novel therapeutic strategy for the treatment of FSHD.


Assuntos
Quadruplex G , Proteínas de Homeodomínio/genética , Distrofia Muscular Facioescapuloumeral/genética , Animais , Berberina/química , Berberina/farmacologia , Fusão Celular , Linhagem Celular Tumoral , Células Clonais , Regulação para Baixo , Elementos Facilitadores Genéticos , Fibrose , Proteínas de Homeodomínio/metabolismo , Ligantes , Masculino , Camundongos Endogâmicos C57BL , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Músculo Esquelético/fisiologia , Distrofia Muscular Facioescapuloumeral/metabolismo , Mioblastos/fisiologia , Motivos de Nucleotídeos , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo
7.
Int J Mol Sci ; 23(19)2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36232961

RESUMO

Male fertility, as manifest by the quantity and progressive motility of spermatozoa, is negatively impacted by obesity, dyslipidaemia and metabolic disease. However, the relative distribution of lipids in spermatozoa and the two compartments which supply lipids for spermatogenesis (seminal fluid and blood serum) has not been studied. We hypothesised that altered availability of lipids in blood serum and seminal fluid may affect the lipid composition and progressive motility of sperm. 60 men of age 35 years (median (range 20-45) and BMI 30.4 kg/m2 (24-36.5) under preliminary investigation for subfertility were recruited at an NHS clinic. Men provided samples of serum and semen, subject to strict acceptance criteria, for analysis of spermatozoa count and motility. Blood serum (n = 60), spermatozoa (n = 26) and seminal fluid (n = 60) were frozen for batch lipidomics analysis. Spermatozoa and seminal fluid had comparable lipid composition but showed marked differences with the serum lipidome. Spermatozoa demonstrated high abundance of ceramides, very-long-chain fatty acids (C20-22), and certain phospholipids (sphingomyelins, plasmalogens, phosphatidylethanolamines) with low abundance of phosphatidylcholines, cholesterol and triglycerides. Men with spermatozoa of low progressive motility had evidence of fewer concentration gradients for many lipid species between blood serum and spermatozoa compartments. Spermatozoa are abundant in multiple lipid species which are likely to contribute to key cellular functions. Lipid metabolism shows reduced regulation between compartments in men with spermatozoa with reduced progressive motility.


Assuntos
Sêmen , Motilidade dos Espermatozoides , Adulto , Ceramidas/metabolismo , Colesterol/metabolismo , Ácidos Graxos/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Plasmalogênios , Sêmen/metabolismo , Contagem de Espermatozoides , Motilidade dos Espermatozoides/fisiologia , Espermatozoides/metabolismo , Esfingomielinas/metabolismo , Triglicerídeos/metabolismo , Adulto Jovem
8.
Angew Chem Int Ed Engl ; 61(2): e202110223, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-34713958

RESUMO

Post-translational modifications (PTMs) enhance the repertoire of protein function and mediate or influence the activity of many cellular processes. The preparation of site-specifically and homogeneously modified proteins, to apply as tools to understand the biological role of PTMs, is a challenging task. Herein, we describe a visible-light-mediated desulfurative C(sp3 )-C(sp3 ) bond forming reaction that enables the site-selective installation of Nϵ -modified sidechains into peptides and proteins of interest. Rapid, operationally simple, and tolerant to ambient atmosphere, we demonstrate the installation of a range of lysine (Lys) PTMs into model peptide systems and showcase the potential of this technology by site-selectively installing an Nϵ Ac sidechain into recombinantly expressed ubiquitin (Ub).


Assuntos
Peptídeos , Proteínas
9.
Br J Clin Pharmacol ; 87(6): 2428-2443, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32154598

RESUMO

AIMS: Advanced therapy medicinal products (ATMPs) represent a new category of medicinal products with a potential for transformative improvements in health outcomes but at exceptionally high prices. Routine adoption of ATMPs requires robust evidence of their cost-effectiveness. METHODS: A systematic literature review of economic evaluations of ATMPs, including gene therapies, somatic cell therapies and tissue-engineered products, was conducted. Literature was searched using MedLine, Embase, PubMed, Cochrane Register, the NHS Economic Evaluation Database and the grey literature of health technology assessment organisations with search terms relating to ATMPs and economic evaluations. Titles were screened independently by 2 reviewers. Articles deemed to meet the inclusion criteria were screened independently on abstract, and full texts reviewed. Study findings were appraised critically. RESULTS: 4514 articles were identified, of which 23 met the inclusion criteria. There was some evidence supporting the cost-effectiveness of: chimeric antigen receptor T-cell therapy axicabtagene-ciloleucel (Yescarta), embryonic neural stem cells, tumour infiltrating lymphocytes, in vitro expanded myoblast, autologous chondrocyte implantation, ex vivo gene therapy (Strimvelis) and voretigene neparvovec (Luxturna). However, estimates of cost-effectiveness were associated with significant uncertainty and high likelihood of bias, resulting from largely unknown long-term outcomes, a paucity of evidence on health state utilities and extensive modelling assumptions. CONCLUSION: There are critical limitations to the economic evidence for ATMPs, most notably in relation to evidence on the durability of treatment effect, and the reliability of opinion-based assumptions necessary when evidence is absent.


Assuntos
Avaliação da Tecnologia Biomédica , Análise Custo-Benefício , Reprodutibilidade dos Testes
10.
Anal Bioanal Chem ; 413(19): 4763-4773, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34254158

RESUMO

Detailed molecular analysis is of increasing importance in research into the regulation of biochemical pathways, organismal growth and disease. Lipidomics in particular is increasingly sought after as it provides insight into molecular species involved in energy storage, signalling and fundamental cellular structures. This has led to the use of a range of tools and techniques to acquire lipidomics data. 31P NMR for lipidomics offers well-resolved head group/lipid class analysis, structural data that can be used to inform and strengthen interpretation of mass spectrometry data and part of a priori structural determination. In the present study, we codify the use of 31P NMR for lipidomics studies to make the technique more accessible to new users and more useful for a wider range of questions. The technique can be used in isolation (phospholipidomics) or as a part of determining lipid composition (lipidomics). We describe the process from sample extraction to data processing and analysis. This pipeline is important because it allows greater thoroughness in lipidomics studies and increases scope for answering scientific questions about lipid-containing systems.


Assuntos
Lipidômica/métodos , Lipídeos/química , Espectroscopia de Ressonância Magnética/métodos , Isótopos de Fósforo/química , Animais , Camundongos
11.
Nucleic Acids Res ; 47(4): 2101-2112, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30534966

RESUMO

The homotetrameric DnaD protein is essential in low G+C content gram positive bacteria and is involved in replication initiation at oriC and re-start of collapsed replication forks. It interacts with the ubiquitously conserved bacterial master replication initiation protein DnaA at the oriC but structural and functional details of this interaction are lacking, thus contributing to our incomplete understanding of the molecular details that underpin replication initiation in bacteria. DnaD comprises N-terminal (DDBH1) and C-terminal (DDBH2) domains, with contradicting bacterial two-hybrid and yeast two-hybrid studies suggesting that either the former or the latter interact with DnaA, respectively. Using Nuclear Magnetic Resonance (NMR) we showed that both DDBH1 and DDBH2 interact with the N-terminal domain I of DnaA and studied the DDBH2 interaction in structural detail. We revealed two families of conformations for the DDBH2-DnaA domain I complex and showed that the DnaA-interaction patch of DnaD is distinct from the DNA-interaction patch, suggesting that DnaD can bind simultaneously DNA and DnaA. Using sensitive single-molecule FRET techniques we revealed that DnaD remodels DnaA-DNA filaments consistent with stretching and/or untwisting. Furthermore, the DNA binding activity of DnaD is redundant for this filament remodelling. This in turn suggests that DnaA and DnaD are working collaboratively in the oriC to locally melt the DNA duplex during replication initiation.


Assuntos
Proteínas de Bactérias/genética , Replicação do DNA/genética , Proteínas de Ligação a DNA/genética , Origem de Replicação/genética , Bacillus subtilis/genética , Proteínas de Bactérias/química , Proteínas de Ligação a DNA/química , DnaB Helicases/química , DnaB Helicases/genética , Espectroscopia de Ressonância Magnética , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Complexo de Reconhecimento de Origem/genética , Ligação Proteica/genética , Domínios Proteicos/genética , Relação Estrutura-Atividade
12.
J Bacteriol ; 203(2)2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33106346

RESUMO

Pseudomonas aeruginosa is a significant nosocomial pathogen and is associated with lung infections in cystic fibrosis (CF). Once established, P. aeruginosa infections persist and are rarely eradicated despite host immune cells producing antimicrobial oxidants, including hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). There is limited knowledge as to how P. aeruginosa senses, responds to, and protects itself against HOCl and HOSCN and the contribution of such responses to its success as a CF pathogen. To investigate the P. aeruginosa response to these oxidants, we screened 707 transposon mutants, with mutations in regulatory genes, for altered growth following HOCl exposure. We identified regulators of antibiotic resistance, methionine biosynthesis, catabolite repression, and PA14_07340, the homologue of the Escherichia coli HOCl-sensor RclR (30% identical), which are required for protection against HOCl. We have shown that RclR (PA14_07340) protects specifically against HOCl and HOSCN stress and responds to both oxidants by upregulating the expression of a putative peroxiredoxin, rclX (PA14_07355). Transcriptional analysis revealed that while there was specificity in the response to HOCl (231 genes upregulated) and HOSCN (105 genes upregulated), there was considerable overlap, with 74 genes upregulated by both oxidants. These included genes encoding the type 3 secretion system, sulfur and taurine transport, and the MexEF-OprN efflux pump. RclR coordinates part of the response to both oxidants, including upregulation of pyocyanin biosynthesis genes, and, in the presence of HOSCN, downregulation of chaperone genes. These data indicate that the P. aeruginosa response to HOCl and HOSCN is multifaceted, with RclR playing an essential role.IMPORTANCE The bacterial pathogen Pseudomonas aeruginosa causes devastating infections in immunocompromised hosts, including chronic lung infections in cystic fibrosis patients. To combat infection, the host's immune system produces the antimicrobial oxidants hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). Little is known about how P. aeruginosa responds to and survives attack from these oxidants. To address this, we carried out two approaches: a mutant screen and transcriptional study. We identified the P. aeruginosa transcriptional regulator, RclR, which responds specifically to HOCl and HOSCN stress and is essential for protection against both oxidants. We uncovered a link between the P. aeruginosa transcriptional response to these oxidants and physiological processes associated with pathogenicity, including antibiotic resistance and the type 3 secretion system.


Assuntos
Ácido Hipocloroso/farmacologia , Oxidantes/farmacologia , Pseudomonas aeruginosa/imunologia , Tiocianatos/farmacologia , Proteínas de Bactérias/fisiologia , Elementos de DNA Transponíveis/genética , Proteínas de Ligação a DNA/fisiologia , Regulação para Baixo , Resistência Microbiana a Medicamentos , Genes Reguladores/genética , Ácido Hipocloroso/imunologia , Ácido Hipocloroso/metabolismo , Mutação , Oxidantes/imunologia , Oxidantes/metabolismo , Plasmídeos , Reação em Cadeia da Polimerase , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , RNA Bacteriano/química , RNA Bacteriano/isolamento & purificação , RNA de Transferência/fisiologia , Tiocianatos/imunologia , Tiocianatos/metabolismo , Transativadores/genética , Fatores de Transcrição/fisiologia , Regulação para Cima
13.
Anal Bioanal Chem ; 412(12): 2851-2862, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32144454

RESUMO

Lipidomics is of increasing interest in studies of biological systems. However, high-throughput data collection and processing remains non-trivial, making assessment of phenotypes difficult. We describe a platform for surveying the lipid fraction for a range of tissues. These techniques are demonstrated on a set of seven different tissues (serum, brain, heart, kidney, adipose, liver, and vastus lateralis muscle) from post-weaning mouse dams that were either obese (> 12 g fat mass) or lean (<5 g fat mass). This showed that the lipid metabolism in some tissues is affected more by obesity than others. Analysis of human serum (healthy non-pregnant women and pregnant women at 28 weeks' gestation) showed that the abundance of several phospholipids differed between groups. Human placenta from mothers with high and low BMI showed that lean placentae contain less polyunsaturated lipid. This platform offers a way to map lipid metabolism with immediate application in metabolic research and elsewhere. Graphical abstract.


Assuntos
Lipidômica/métodos , Lipídeos/análise , Lipídeos/farmacocinética , Obesidade/fisiopatologia , Magreza/fisiopatologia , Animais , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Distribuição Tecidual
14.
Angew Chem Int Ed Engl ; 59(52): 23659-23667, 2020 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-32893423

RESUMO

The development of site-selective chemistry targeting the canonical amino acids enables the controlled installation of desired functionalities into native peptides and proteins. Such techniques facilitate the development of polypeptide conjugates to advance therapeutics, diagnostics, and fundamental science. We report a versatile and selective method to functionalize peptides and proteins through free-radical-mediated dechalcogenation. By exploiting phosphine-induced homolysis of the C-Se and C-S bonds of selenocysteine and cysteine, respectively, we demonstrate the site-selective installation of groups appended to a persistent radical trap. The reaction is rapid, operationally simple, and chemoselective. The resulting aminooxy linker is stable under a variety of conditions and selectively cleavable in the presence of a low-oxidation-state transition metal. We have explored the full scope of this reaction using complex peptide systems and a recombinantly expressed protein.

15.
J Biol Chem ; 293(9): 3180-3200, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29326168

RESUMO

Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered signaling molecule important for the survival of Firmicutes, a large bacterial group that includes notable pathogens such as Staphylococcus aureus However, the exact role of this molecule has not been identified. dacA, the S. aureus gene encoding the diadenylate cyclase enzyme required for c-di-AMP production, cannot be deleted when bacterial cells are grown in rich medium, indicating that c-di-AMP is required for growth in this condition. Here, we report that an S. aureus dacA mutant can be generated in chemically defined medium. Consistent with previous findings, this mutant had a severe growth defect when cultured in rich medium. Using this growth defect in rich medium, we selected for suppressor strains with improved growth to identify c-di-AMP-requiring pathways. Mutations bypassing the essentiality of dacA were identified in alsT and opuD, encoding a predicted amino acid and osmolyte transporter, the latter of which we show here to be the main glycine betaine-uptake system in S. aureus. Inactivation of these transporters likely prevents the excessive osmolyte and amino acid accumulation in the cell, providing further evidence for a key role of c-di-AMP in osmotic regulation. Suppressor mutations were also obtained in hepS, hemB, ctaA, and qoxB, coding proteins required for respiration. Furthermore, we show that dacA is dispensable for growth in anaerobic conditions. Together, these findings reveal an essential role for the c-di-AMP signaling network in aerobic, but not anaerobic, respiration in S. aureus.


Assuntos
Aminoácidos Cíclicos/metabolismo , Viabilidade Microbiana , Osmose , Staphylococcus aureus/fisiologia , Anaerobiose , Proteínas de Bactérias/genética , Betaína/metabolismo , Tamanho Celular , Potenciais da Membrana , Mutação , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/citologia , Staphylococcus aureus/metabolismo
16.
Chemistry ; 25(27): 6840-6846, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-30875128

RESUMO

A magnesium complex (1) featuring a bidentate aminopyridinato ligand is a remarkably selective catalyst for the dehydrocoupling of amine-boranes. This reaction proceeds to completion with low catalyst loadings (1 mol %) under mild conditions (60 °C), exceeding previously reported s-block systems in terms of selectivity, rate, and turnover number (TON). Mechanistic studies by in situ NMR analysis reveals the reaction to be first order in both catalyst and substrate. A reaction mechanism is proposed to account for these findings, with the high TON of the catalyst attributed to the bidentate nature of the ligand, which allows for reversible deprotonation of the substrate and regeneration of 1 as a stable resting state.

17.
Nanotechnology ; 30(50): 505102, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31509807

RESUMO

We report on the synthesis of water-soluble gold nanoclusters capped with polyethylene glycol (PEG)-based ligands and further functionalized with folic acid for specific cellular uptake. The dihydrolipoic acid-PEG-based ligands terminated with -OMe, -NH2 and -COOH functional groups are produced and used for surface passivation of Au nanoclusters (NCs) with diameters <2 nm. The produced sub 2 nm Au NCs possess long-shelf life and are stable in physiologically relevant environments (temperature and pH), are paramagnetic and biocompatible. The paramagnetism of Au NCs in solution is also reported. The functional groups on the capping ligands are used for direct conjugation of targeting molecules onto Au NCs without the need for post synthesis modification. Folic acid (FA) is attached via an amide group and effectively target cells expressing the folate receptor. The combination of targeting ability, biocompatibility and paramagnetism in FA-functionalized Au NCs is of relevance for their exploitation in nanomedicine for targeted imaging.


Assuntos
Receptores de Folato com Âncoras de GPI/análise , Ácido Fólico/química , Ouro/química , Nanopartículas Metálicas/química , Linhagem Celular Tumoral , Humanos , Nanotecnologia , Polietilenoglicóis/química
18.
Bull World Health Organ ; 96(7): 498-505, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29962552

RESUMO

Primary care lags behind secondary care in the reporting of, and learning from, incidents that put patient safety at risk. In primary care, there is no universally agreed approach to classifying the severity of harm arising from such patient-safety incidents. This lack of an agreed approach limits learning that could lead to the prevention of injury to patients. In a review of research on patient safety in primary care, we identified 21 existing approaches to the classification of harm severity. Using the World Health Organization's (WHO's) International Classification for Patient Safety as a reference, we undertook a framework analysis of these approaches. We then developed a new system for the classification of harm severity. To assess and classify harm, most existing approaches use measures of symptom duration (11/21), symptom severity (11/21) and/or the level of intervention required to manage the harm (14/21). However, few of these approaches account for the deleterious effects of hospitalization or the psychological stress that may be experienced by patients and/or their relatives. The new classification system we developed builds on WHO's International Classification for Patient Safety and takes account not only of hospitalization and psychological stress but also of so-called near misses and uncertain outcomes. The constructs we have outlined have the potential to be applied internationally, across primary-care settings, to improve both the detection and prevention of incidents that cause the most severe harm to patients.


Les soins primaires ont du retard sur les soins secondaires en ce qui concerne l'établissement de rapports sur les incidents qui menacent la sécurité des patients et les enseignements qui en découlent. Dans le cas des soins primaires, il n'existe pas de méthode universellement acceptée pour classifier la gravité des dommages résultant d'incidents liés à la sécurité des patients. L'absence d'une telle méthode limite les enseignements qui pourraient favoriser la prévention des traumatismes chez les patients. Dans le cadre d'une analyse documentaire sur la sécurité des patients en matière de soins primaires, nous avons repéré l'existence de 21 méthodes de classification de la gravité des dommages. En prenant comme référence la Classification internationale pour la sécurité des patients de l'Organisation mondiale de la Santé (OMS), nous avons entrepris une analyse du cadre de ces méthodes. Nous avons ensuite conçu un nouveau système de classification de la gravité des dommages. Pour évaluer et classifier les dommages, la plupart des méthodes existantes utilisent des mesures portant sur la durée des symptômes (11/21), la gravité des symptômes (11/21) et/ou le niveau d'intervention requis pour prendre en charge les dommages (14/21). Néanmoins, rares sont celles qui tiennent compte des effets délétères de l'hospitalisation ou du stress psychologique que peuvent ressentir les patients et/ou leurs proches. Le nouveau système de classification que nous avons élaboré repose sur la Classification internationale pour la sécurité des patients de l'OMS et tient compte non seulement de l'hospitalisation et du stress psychologique, mais aussi de ce qu'il est convenu d'appeler les accidents évités de justesse et des résultats incertains. Les concepts que nous avons définis peuvent être appliqués dans les établissements de soins primaires du monde entier pour améliorer la détection et la prévention des incidents qui provoquent les plus graves dommages pour les patients.


La atención primaria queda por debajo de la atención secundaria en la notificación y el aprendizaje de incidentes que ponen en riesgo la seguridad del paciente. En la atención primaria, no existe un enfoque universalmente aceptado para clasificar la gravedad del daño que surge de tales incidentes que afectan a la seguridad del paciente. Esta falta de un enfoque consensuado limita el aprendizaje que podría conducir a la prevención de lesiones a los pacientes. En una revisión de la investigación sobre la seguridad del paciente en la atención primaria, se identificaron 21 enfoques existentes para la clasificación de la gravedad del daño. Con la Clasificación Internacional para la Seguridad del Paciente de la Organización Mundial de la Salud (OMS) como referencia, se llevó a cabo un análisis del marco de estos enfoques. A continuación, se desarrolló un nuevo sistema para la clasificación de la gravedad del daño. Para evaluar y clasificar el daño, la mayoría de los enfoques existentes usan medidas de la duración de los síntomas (11/21), la gravedad de los síntomas (11/21) y/o el nivel de intervención necesario para gestionar el daño (14/21). Sin embargo, pocos de estos enfoques explican los efectos nocivos de la hospitalización o el estrés psicológico que pueden experimentar los pacientes y/o sus familiares. El nuevo sistema de clasificación desarrollado se basa en la Clasificación Internacional para la Seguridad del Paciente de la OMS y tiene en cuenta no solo la hospitalización y el estrés psicológico, sino también los denominados casi accidentes y los resultados inciertos. Los constructos descritos tienen el potencial de aplicarse internacionalmente, en entornos de atención primaria, para mejorar tanto la detección como la prevención de incidentes que causan los daños más graves a los pacientes.


Assuntos
Segurança do Paciente/normas , Atenção Primária à Saúde , Qualidade da Assistência à Saúde , Hospitalização , Humanos , Erros Médicos/prevenção & controle , Organização Mundial da Saúde
19.
Palliat Med ; 32(8): 1353-1362, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29856273

RESUMO

BACKGROUND: Patients receiving palliative care are vulnerable to patient safety incidents but little is known about the extent of harm caused or the origins of unsafe care in this population. AIM: To quantify and qualitatively analyse serious incident reports in order to understand the causes and impact of unsafe care in a population receiving palliative care. DESIGN: A mixed-methods approach was used. Following quantification of type of incidents and their location, a qualitative analysis using a modified framework method was used to interpret themes in reports to examine the underlying causes and the nature of resultant harms. SETTING AND PARTICIPANTS: Reports to a national database of 'serious incidents requiring investigation' involving patients receiving palliative care in the National Health Service (NHS) in England during the 12-year period, April 2002 to March 2014. RESULTS: A total of 475 reports were identified: 266 related to pressure ulcers, 91 to medication errors, 46 to falls, 21 to healthcare-associated infections (HCAIs), 18 were other instances of disturbed dying, 14 were allegations against health professions, 8 transfer incidents, 6 suicides and 5 other concerns. The frequency of report types differed according to the care setting. Underlying causes included lack of palliative care experience, under-resourcing and poor service coordination. Resultant harms included worsened symptoms, disrupted dying, serious injury and hastened death. CONCLUSION: Unsafe care presents a risk of significant harm to patients receiving palliative care. Improvements in the coordination of care delivery alongside wider availability of specialist palliative care support may reduce this risk.


Assuntos
Acidentes/estatística & dados numéricos , Erros de Medicação/estatística & dados numéricos , Cuidados Paliativos/estatística & dados numéricos , Segurança do Paciente/estatística & dados numéricos , Gestão de Riscos/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Doença Iatrogênica/epidemiologia , Masculino , Pessoa de Meia-Idade , Úlcera por Pressão/epidemiologia , Reino Unido/epidemiologia
20.
J Shoulder Elbow Surg ; 27(12): 2191-2197, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30093232

RESUMO

BACKGROUND: Stemless humeral components benefit from less morbidity, better reproduction of the humeral anatomy, ease of revision, and fewer stem-related complications. Encouraging results are available up to 9 years after surgery from the designer's series. This is an independent study of 100 consecutive Eclipse stemless prostheses for osteoarthritis with a minimum 2-year follow-up (range, 2-6 years). METHODS: We included only total shoulder arthroplasties performed for osteoarthritis. The primary outcome was the Oxford Shoulder Score (OSS) after 2 years. Secondary outcome measures were change in shoulder range of movement and radiographic analysis of prosthesis size and position. RESULTS: The mean OSS at 2 years was 38 of 48, with a mean improvement of +19 points (range, +17 to +22 points; P < .001). There was no significant deterioration in OSS after 3 or 4 years' follow-up. Statistically significant improvement was seen in arm elevation and external rotation (P < .001). There were 5 reoperations-1 for impingement of the biceps stump and 4 revisions to reverse arthroplasty for cuff failure. Of the prostheses, 92% were sized within 2 mm of the anatomic head size, and in 76% of prostheses, the center of rotation was within 3 mm of the native anatomy. An incomplete radiolucent line was present in zone B (around the cage screw) in a single patient at 2 years following surgery. There were no cases of loosening or infection. CONCLUSION: The functional and radiographic outcomes of Eclipse total shoulder replacement are excellent. We were able to accurately reproduce the native anatomy in the majority of cases, with no implant loosening, at 2 to 6 years' follow-up.


Assuntos
Artroplastia do Ombro , Articulação do Ombro/cirurgia , Prótese de Ombro , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/cirurgia , Desenho de Prótese , Amplitude de Movimento Articular , Reoperação/estatística & dados numéricos , Estudos Retrospectivos , Articulação do Ombro/diagnóstico por imagem , Articulação do Ombro/fisiopatologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA