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1.
Artigo em Inglês | MEDLINE | ID: mdl-38707714

RESUMO

Purpose: Evidence-based practice (EBP) is associated with improved treatment outcomes and survival in cancer patients. Engagement from therapeutic radiographers/radiation therapists (RTTs) in research, has been identified as a challenge. The aim of this survey was to gain an understanding of RTT attitudes to research in Scotland. Methods: This was a prospective study that used a mixed method cross-sectional survey, with an online survey tool (Webropol). The survey was developed with collaborators from all Scottish Radiotherapy Centres (n = 5) and piloted by 6 conveniently sampled RTT and validated by 8 experienced RTTs. The survey comprised 29 items, 7 selection-based demographic questions, and 18 statements with a Likert 5-point metric scale rating (1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree). The validity was measured with the content validity index (CVI) and item-CVI by 8 experienced RTTs. Low scoring I-CVI (<0.78) questions were removed.A total of 314 RTTs working in Scottish Radiotherapy Centres were invited to participate. Approvals were given by each Head of department (HoD), who also confirmed number of RTTs. Results: A total of 102/314 (32.5 %) RTTs responded. The majority of RTTs agreed they were confident they had sufficient research skills to inform EBP (n = 58/102, 56.9 %), felt confident discussing EBP with colleagues (n = 67, 65.7 %) and felt research was important for role development (n = 89, 87.2 %). Low mean scores and standard deviation (SD) were observed for the following: "I know how to get involved in research" 3.2 (1.2), "I have been given the opportunity to get involved in research" 3.2 (1.1), and "I am well informed about current research projects in my department" 3.2 (1.1). 57.8 % (n = 59) of RTTs disagreed they were confident adequate time would be provided to be involved in research. Conclusion: The survey results demonstrated a predominantly positive attitude to research amongst RTTs working in Scottish centres, with most common perceived barriers being access to protected time and staff; training, and support.

2.
Thromb J ; 22(1): 39, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38654303

RESUMO

Formyl peptide receptors (FPRs) are members of seven transmembrane G protein-coupled receptors superfamily that exhibit different responses based on the nature of stimulating ligand type. FPRs have been shown to be present in platelets and regulate their function. However, the effect of formyl peptide receptor 2 (FPR2/ALX) lipid ligands on platelets has not yet been addressed. Hence, we sought to study the role of FPR2/ALX ligand and lipoxin A4 lipid analogue, BML-111, in the modulation of platelet function and thrombus formation. Immunofluorescence microscopy showed subcellular distribution and peripheral mobilisation of FPR2/ALX in stimulated platelets. This variation in distribution was further confirmed using flow cytometry. BML-111 inhibited a range of platelet activities in a dose-dependent manner in response to several platelet agonists. This included aggregation, fibrinogen binding to integrin αIIbß3, α-granule secretion, dense granule secretion, Ca2 + mobilisation and integrin αIIbß3-mediated outside-in signaling. The selectivity of BML-111 for FPR2/ALX was confirmed using FPR2/ALX deficient mice in flow cytometry assays. In vitro thrombus formation was also inhibited by various concentrations of BML-111. Moreover, the levels of vasodilator stimulated phosphorylation (VASP-S157) increased significantly after BML-111 treatment in resting and stimulated platelets via protein kinase A (PKA) independently of cyclic adenosine monophosphate (cAMP) signaling. Together, our findings demonstrate the significance of BML-111 as a modulator of platelet function via FPR2/ALX and unravel the thrombo-protective potentials of BML-111 induced signaling against thrombo-inflammatory diseases.

3.
Am J Clin Nutr ; 119(5): 1175-1186, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38484976

RESUMO

BACKGROUND: Extracellular vesicles (EVs) are proposed to play a role in the development of cardiovascular diseases (CVDs) and are considered emerging markers of CVDs. n-3 PUFAs are abundant in oily fish and fish oil and are reported to reduce CVD risk, but there has been little research to date examining the effects of n-3 PUFAs on the generation and function of EVs. OBJECTIVES: We aimed to investigate the effects of fish oil supplementation on the number, generation, and function of EVs in subjects with moderate risk of CVDs. METHODS: A total of 40 participants with moderate risk of CVDs were supplemented with capsules containing either fish oil (1.9 g/d n-3 PUFAs) or control oil (high-oleic safflower oil) for 12 wk in a randomized, double-blind, placebo-controlled crossover intervention study. The effects of fish oil supplementation on conventional CVD and thrombogenic risk markers were measured, along with the number and fatty acid composition of circulating and platelet-derived EVs (PDEVs). PDEV proteome profiles were evaluated, and their impact on coagulation was assessed using assays including fibrin clot formation, thrombin generation, fibrinolysis, and ex vivo thrombus formation. RESULTS: n-3 PUFAs decreased the numbers of circulating EVs by 27%, doubled their n-3 PUFA content, and reduced their capacity to support thrombin generation by >20% in subjects at moderate risk of CVDs. EVs derived from n-3 PUFA-enriched platelets in vitro also resulted in lower thrombin generation, but did not alter thrombus formation in a whole blood ex vivo assay. CONCLUSIONS: Dietary n-3 PUFAs alter the number, composition, and function of EVs, reducing their coagulatory activity. This study provides clear evidence that EVs support thrombin generation and that this EV-dependent thrombin generation is reduced by n-3 PUFAs, which has implications for prevention and treatment of thrombosis. CLINICAL TRIAL REGISTRY: This trial was registered at clinicaltrials.gov as NCT03203512.


Assuntos
Coagulação Sanguínea , Plaquetas , Estudos Cross-Over , Vesículas Extracelulares , Ácidos Graxos Ômega-3 , Humanos , Vesículas Extracelulares/metabolismo , Ácidos Graxos Ômega-3/farmacologia , Masculino , Feminino , Pessoa de Meia-Idade , Método Duplo-Cego , Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/metabolismo , Plaquetas/efeitos dos fármacos , Suplementos Nutricionais , Doenças Cardiovasculares/prevenção & controle , Adulto , Óleos de Peixe/farmacologia , Óleos de Peixe/administração & dosagem , Idoso , Ácidos Graxos/metabolismo
4.
Platelets ; 34(1): 2264940, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37822056

RESUMO

Multiple myeloma (MM) and its precursor states, smoldering myeloma (SM) and monoclonal gammopathy of undetermined significance (MGUS) are associated with increased incidence of thrombosis, however the cause of this is unknown. Lenalidomide treatment of MM substantially improves patient survival, although significantly increases thrombotic risk by an unknown mechanism. This pilot study aimed to establish the impact of MM and its treatment with Lenalidomide on platelet function. We analyzed platelet function in MGUS, SM and MM compared to healthy controls. We report an increase in platelet reactivity in MGUS, SM, and MM where increases in fibrinogen binding, P-selectin exposure, altered receptor expression, elevated levels of aggregation and enhanced sensitivity to agonist stimulation were observed. We also demonstrate an increase in patient platelet reactivity post Lenalidomide treatment compared to pre-treatment. We show Lenalidomide treatment of platelets ex vivo increased reactivity that was associated with formation of larger thrombi at arterial shear rates but not venous shear rates. This study demonstrates a clear increase in platelet reactivity and prothrombotic potential in patients with MGUS, SM and MM which is elevated further upon treatment with Lenalidomide. Our observations suggest that more detailed studies are warranted to determine mechanisms of thrombotic complications to enable the development of new preventative strategies that specifically target platelets.


What is the context?Multiple myeloma is associated with increased risk of thrombosis, although the potential role of platelets in this has not been evaluated.What is new?We show in this pilot study that multiple myeloma and its precursor states of smoldering myeloma and monoclonal gammopathy of undetermined significance are associated with increased levels of platelet responses. This is further exacerbated by treatment with the immunomodulatory drug lenalidomide.What is the impact?This study suggests that more detailed studies are warranted to explore the mechanisms that cause these effects in a larger population of patients, since this may reveal new approaches to prevent myeloma-associated thrombotic complications.


Assuntos
Gamopatia Monoclonal de Significância Indeterminada , Mieloma Múltiplo , Trombose , Humanos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/complicações , Lenalidomida/farmacologia , Lenalidomida/uso terapêutico , Projetos Piloto , Trombose/complicações , Gamopatia Monoclonal de Significância Indeterminada/complicações
5.
Front Cardiovasc Med ; 10: 1227499, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37753164

RESUMO

Aims: Risks and outcomes of myocardial infarction (MI) are different between men and women and some studies have demonstrated that the latter have a higher risk of mortality. Whilst there are many reasons for this, it may also partially be linked to stronger innate and adaptive immune responses mounted by females compared to males. However, little is known about how sex impacts the coronary microvessels, the site where inflammatory processes take place, after an MI. Intravital and laser speckle microscopy was used to image coronary microvessels and ventricular perfusion in vivo in response to myocardial ischaemia-reperfusion (IR) injury in male and female mice. Interleukin-36 (IL-36) is the latest addition to the IL-1 superfamily of pro-inflammatory cytokines and has recently been shown to mediate inflammation in a number of non-cardiovascular diseases. Its role in mediating potential sex-related microcirculatiory pertubations in the heart are unknown. Therefore, the vasculoprotective efficacy of an IL-36 receptor antagonist (IL-36Ra) was also investigated. Methods and results: Immunostaining and flow cytometry demonstrated higher expression of IL-36 and its receptor in female hearts, an observation confirmed in human samples. Intravital imaging of the anaesthetised mouse beating heart identified significantly greater neutrophil recruitment in female hearts, but a greater burden of thrombotic disease in male hearts. Male mice had reduced functional capillary density and were unable to restore perfusion to baseline values as effectively as females. However, female mice had significantly larger infarcts. Interestingly, IL-36Ra decreased inflammation, improved perfusion, and reduced infarct size in both sexes despite increasing platelet presence in male hearts. Mechanistically, this was explained by IL-36Ra attenuating endothelial oxidative damage and VCAM-1 expression. Importantly, IL-36Ra administration during ischaemia was critical for vasculoprotection to be realised. Conclusion: This novel study identified notable sex-related differences in the coronary microcirculatory response to myocardial IR injury which may explain why some studies have noted poorer outcomes in women after MI. Whilst contemporary MI treatment focuses on anti-platelet strategies, the heightened presence of neutrophils in female IR injured coronary microvessels necessitates the development of an effective anti-inflammatory approach for treating female patients. We also emphasise the importance of early intervention during the ischaemic period in order to maximise therapeutic effectiveness.

6.
Res Pract Thromb Haemost ; 7(5): 100200, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37601014

RESUMO

Background: Factor XIII (FXIII) is an important proenzyme in the hemostatic system. The plasma-derived enzyme activated FXIII cross-links fibrin fibers within thrombi to increase their mechanical strength and cross-links fibrin to fibrinolytic inhibitors, specifically α2-antiplasmin, to increase resistance to fibrinolysis. We have previously shown that cellular FXIII (factor XIII-A [FXIII-A]), which is abundant in the platelet cytoplasm, is externalized onto the activated membrane and cross-links extracellular substrates. The contribution of cellular FXIII-A to platelet activation and platelet function has not been extensively studied. Objectives: This study aims to identify the role of platelet FXIII-A in platelet function. Methods: We used normal healthy platelets with a cell permeable FXIII inhibitor and platelets from FXIII-deficient patients as a FXIII-free platelet model in a range of platelet function and clotting tests. Results: Our data demonstrate that platelet FXIII-A enhances fibrinogen binding to the platelet surface upon agonist stimulation and improves the binding of platelets to fibrinogen and aggregation under flow in a whole-blood thrombus formation assay. In the absence of FXIII-A, platelets show reduced sensitivity to agonist stimulation, including decreased P-selectin exposure and fibrinogen binding. We show that FXIII-A is involved in platelet spreading where a lack of FXIII-A reduces the ability of platelets to fully spread on fibrinogen and collagen. Our data demonstrate that platelet FXIII-A is important for clot retraction where clots formed in its absence retracted to a lesser extent. Conclusion: Overall, this study shows that platelet FXIII-A functions during thrombus formation by aiding platelet activation and thrombus retraction in addition to its antifibrinolytic roles.

7.
J Thromb Haemost ; 21(8): 2248-2259, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37085037

RESUMO

BACKGROUND: The response of platelets to activating stimuli and pharmaceutical agents varies greatly within the normal population. Current platelet function tests are used to measure end-point levels of platelet activation without taking the speed at which platelets activate into account, potentially missing vital metrics to characterize platelet reactivity. OBJECTIVES: To identify variability, to agonists and among individuals, in platelet activation kinetics and assess the impact of this on thrombus formation. METHODS: We have developed a bespoke real-time flow cytometry assay and analysis package to measure the rate of platelet activation over time using 2 parameters of platelet activation, fibrinogen binding and P-selectin exposure. RESULTS: The rate of platelet activation varied considerably within the normal population but did not correlate with maximal platelet activation, demonstrating that platelet activation rate is a separate and novel metric to describe platelet reactivity. The relative rate of platelet response between agonists was strongly correlated, suggesting that a central control mechanism regulates the rate of platelet response to all agonists. CONCLUSION: For the first time, we have shown that platelet response rate corresponds to thrombus size and structure, wherein faster responders form larger, more densely packed thrombi at arterial, but crucially not venous, shear. We have demonstrated that the rate of platelet activation is an important metric in stratifying individual platelet responses and will provide a novel focus for the design and development of antiplatelet therapy, targeting high-shear thrombosis without exacerbating bleeding at low shear.


Assuntos
Ativação Plaquetária , Trombose , Humanos , Trombose/metabolismo , Plaquetas/metabolismo , Testes de Função Plaquetária , Artérias , Agregação Plaquetária
8.
Thromb Haemost ; 122(7): 1115-1129, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35253142

RESUMO

Cucurbitacins are dietary compounds that have been shown to elicit a range of anti-tumour, anti-inflammatory and anti-atherosclerotic activities. Originally identified as signal transducer and activator of transcription, STAT, inhibitors, a variety of mechanisms of action have since been described, including dysregulation of the actin cytoskeleton and disruption of integrin function. Integrin outside-in signalling and cytoskeletal rearrangements are critical for the propagation of stable thrombus formation and clot retraction following platelet adhesion at the site of vessel damage. The effects of cucurbitacins on platelet function and thrombus formation are unknown. We report for the first time anti-platelet and anti-thrombotic effects of cucurbitacins B, E and I in human platelets. Treatment of platelets with cucurbitacins resulted in attenuation of platelet aggregation, secretion and fibrinogen binding following stimulation by platelet agonists. Cucurbitacins were also found to potently inhibit other integrin- and cytoskeleton-mediated events, including adhesion, spreading and clot retraction. Further investigation of cytoskeletal dynamics found treatment with cucurbitacins altered cofilin phosphorylation, enhanced activation and increased F actin polymerisation and microtubule assembly. Disruption to cytoskeletal dynamics has been previously shown to impair integrin activation, platelet spreading and clot retraction. Anti-platelet properties of cucurbitacins were found to extend to a disruption of stable thrombus formation, with an increase in thrombi instability and de-aggregation under flow. Our research identifies novel, anti-platelet and anti-thrombotic actions of cucurbitacins that appear to be linked to dysregulation of cytoskeletal dynamics and integrin function.


Assuntos
Complexo Glicoproteico GPIIb-IIIa de Plaquetas , Trombose , Plaquetas/metabolismo , Cucurbitacinas/metabolismo , Cucurbitacinas/farmacologia , Citoesqueleto/metabolismo , Humanos , Microtúbulos/metabolismo , Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Trombose/metabolismo
9.
J Am Ceram Soc ; 105(12): 7238-7253, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36618556

RESUMO

The Hadamard-Rybczynski equation describes the steady-state buoyant rise velocity of an unconfined spherical bubble in a viscous liquid. This solution has been experimentally validated for the case where the liquid viscosity is held constant. Here, we extend this result for non-isothermal conditions, by developing a solution for bubble position in which we account for the time-dependent liquid viscosity, liquid and gas densities, and bubble radius. We validate this solution using experiments in which spherical bubbles are created in a molten silicate liquid by cutting gas cavities into glass sheets, which are stacked, then heated through the glass transition interval. The bubble-bearing liquid, which has a strongly temperature-dependent viscosity, is subjected to various heating and cooling programs such that the bubble rise velocity varies through the experiment. We find that our predictions match the final observed position of the bubble measured in blocks of cooled glass to within the experimental uncertainty, even after the application of a complex temperature-time pathway. We explore applications of this solution for industrial, artistic, and natural volcanological applied problems.

10.
Blood Adv ; 5(20): 4017-4030, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34474473

RESUMO

Accurate and comprehensive assessment of platelet function across cohorts of donors may be key to understanding the risk of thrombotic events associated with cardiovascular disease, and, hence, to help personalize the application of antiplatelet drugs. However, platelet function tests can be difficult to perform and analyze; they also can be unreliable or uninformative and poorly standardized across studies. The Platelet Phenomic Analysis (PPAnalysis) assay and associated open-source software platform were developed in response to these challenges. PPAnalysis utilizes preprepared freeze-dried microtiter plates to provide a detailed characterization of platelet function. The automated analysis of the high-dimensional data enables the identification of subpopulations of donors with distinct platelet function phenotypes. Using this approach, we identified that the sensitivity of a donor's platelets to an agonist and their capacity to generate a functional response are distinct independent metrics of platelet reactivity. Hierarchical clustering of these metrics identified 6 subgroups with distinct platelet phenotypes within healthy cohorts, indicating that platelet reactivity does not fit into the traditional simple categories of "high" and "low" responders. These platelet phenotypes were found to exist in 2 independent cohorts of healthy donors and were stable on recall. PPAnalysis is a powerful tool for stratification of cohorts on the basis of platelet reactivity that will enable investigation of the causes and consequences of differences in platelet function and drive progress toward precision medicine.


Assuntos
Plaquetas , Trombose , Humanos , Inibidores da Agregação Plaquetária , Testes de Função Plaquetária
11.
Liver Int ; 41(12): 2934-2943, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34392596

RESUMO

BACKGROUND AND AIMS: IgG4 sclerosing cholangitis (IgG4-SC) is the biliary component of the multisystem IgG4-related disease. We aimed to investigate the clinical features, demographics, treatment response and outcomes of IgG4-SC in a large Australian cohort. METHODS: We conducted nationwide retrospective cohort via the Australian Liver Association Clinical Trials Network (ALA-CRN). 39 sites were invited to participate. IgG4-SC was defined by the clinical diagnostic criteria established by the Japanese Biliary Association in 2012. Data were collected on patient demographic, clinical and laboratory information, presenting features, response to therapy and clinical outcomes. RESULTS: 67 patients meet inclusion criteria from 22 sites. 76% were male with mean age of 63.3 ± 14.5 years and a median IgG4 level of 3.6 g/L [0.09-67.1]. The most frequent presenting symptom was jaundice (62%) and abdominal pain (42%) and Type 1 biliary stricturing (52%) at the distal common bile duct was the most frequent biliary tract finding. Prednisolone was used as a primary treatment in 61 (91%) and partial or complete response occurred in 95% of subjects. Relapse was common (42%) in those who ceased medical therapy. After a median follow up of 3.9 years there was one hepatocellular carcinoma and no cholangiocarcinomas. CONCLUSIONS: Our study confirms the preponderance of IgG4-SC in males and highlights the steroid response nature of this condition although relapse is common after steroid cessation. Progression to malignancy was uncommon.


Assuntos
Neoplasias dos Ductos Biliares , Colangite Esclerosante , Idoso , Austrália/epidemiologia , Neoplasias dos Ductos Biliares/diagnóstico , Ductos Biliares Intra-Hepáticos/patologia , Colangite Esclerosante/diagnóstico , Colangite Esclerosante/tratamento farmacológico , Colangite Esclerosante/patologia , Diagnóstico Diferencial , Humanos , Imunoglobulina G , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico , Estudos Retrospectivos
12.
ERJ Open Res ; 7(3)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34262966

RESUMO

BACKGROUND: Patients with some neuronal hypersensitivity syndromes experience increased autonomic symptoms. Chronic cough is thought to be a neuronal hypersensitivity disorder and, therefore, may be associated with increased autonomic symptoms. METHODS: 96 chronic cough subjects were recruited from the tertiary cough clinic based at Wythenshawe Hospital, Manchester, UK; 76 healthy controls were also recruited. Subjects were aged >18 years. Those with significant respiratory disease, significant smoking history or taking medication known to affect cough or autonomic function were excluded. Subjects completed the Composite Autonomic Symptom Score (COMPASS) 31 autonomic symptom questionnaire, the Cough Quality of Life Questionnaire (CQLQ) and a cough severity visual analogue scale (VAS). RESULTS: 96 chronic cough subjects and 76 healthy volunteers were included in the final analysis. Mann-Whitney U-tests comparing COMPASS 31 scores in both groups showed that the total COMPASS 31 score was significantly higher in the patient group (median 18.4, interquartile range (IQR) 7.5-32.0) than the control group (median 3.6, IQR 1.1-9.5; p<0.001). The chronic cough subjects had significantly higher symptom scores than the healthy volunteer groups in all domains (p≤0.001) except vasomotor symptoms (p=0.770). There was a positive association between COMPASS 31 and CQLQ in the patient group (p<0.001, r=0.432) but not COMPASS 31 and VAS (p=0.227). INTERPRETATION: Chronic cough patients do indeed report more frequent and severe autonomic symptoms than healthy volunteers, indicating that this population may suffer from dysautonomia. At present, it remains unclear whether this occurs as a result of the cough or whether both the cough and dysfunction are part of some wider vagal pathology.

13.
Blood ; 138(16): 1481-1489, 2021 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-34315173

RESUMO

A subset of patients with coronavirus disease 2019 (COVID-19) become critically ill, suffering from severe respiratory problems and also increased rates of thrombosis. The causes of thrombosis in severely ill patients with COVID-19 are still emerging, but the coincidence of critical illness with the timing of the onset of adaptive immunity could implicate an excessive immune response. We hypothesized that platelets might be susceptible to activation by anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) antibodies and might contribute to thrombosis. We found that immune complexes containing recombinant SARS-CoV-2 spike protein and anti-spike immunoglobulin G enhanced platelet-mediated thrombosis on von Willebrand factor in vitro, but only when the glycosylation state of the Fc domain was modified to correspond with the aberrant glycosylation previously identified in patients with severe COVID-19. Furthermore, we found that activation was dependent on FcγRIIA, and we provide in vitro evidence that this pathogenic platelet activation can be counteracted by the therapeutic small molecules R406 (fostamatinib) and ibrutinib, which inhibit tyrosine kinases Syk and Btk, respectively, or by the P2Y12 antagonist cangrelor.


Assuntos
Plaquetas/patologia , COVID-19/complicações , Imunoglobulina G/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Trombose/patologia , Fator de von Willebrand/metabolismo , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Complexo Antígeno-Anticorpo/imunologia , Plaquetas/imunologia , Plaquetas/metabolismo , COVID-19/imunologia , COVID-19/virologia , Glicosilação , Humanos , Ativação Plaquetária/imunologia , Trombose/imunologia , Trombose/virologia , Fator de von Willebrand/genética
14.
Free Radic Biol Med ; 165: 395-400, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33548451

RESUMO

BACKGROUND: Platelets release platelet-derived extracellular vesicles (PDEVs) upon activation - in a process that is regulated by generation of reactive oxygen species (ROS). Platelet NADPH oxidase-1 (Nox-1) contributes to ROS generation and thrombus formation downstream of the collagen receptor GPVI. OBJECTIVES: We aimed to investigate whether PDEVs contain Nox-1 and whether this is relevant for PDEV-induced platelet activation. METHODS: PDEVs were isolated through serial centrifugation after platelet activation with thrombin receptor agonist TRAP-6 (activated PDEVs) or in the absence of agonist (resting PDEVs). The physical properties of PDEVs were analyzed through nanoparticle tracking analysis. Nox-1 levels, fibrinogen binding and P-selectin exposure were measured using flow cytometry, and protein levels quantified by immunoblot analysis. ROS were quantified using DCF fluorescence and electron paramagnetic resonance. RESULTS: Nox-1 was found to be increased on the platelet outer membrane upon activation and was present in PDEVs. PDEVs induced platelet activation, while co-addition of GPVI agonist collagen-related peptide (CRP) did not potentiate this response. PDEVs were shown to be able to generate superoxide in a process at least partially mediated by Nox-1, while Nox-1 inhibition with ML171 (also known as 2-APT) did not influence PDEV production. Finally, inhibition of Nox-1 abrogated PDEV-mediated platelet activation. CONCLUSIONS: PDEVs are able to generate superoxide, bind to and activate platelets in a process mediated by Nox-1. These data provide novel mechanisms by which Nox-1 potentiates platelet responses, thus proposing Nox-1 inhibition as a feasible strategy to treat and prevent thrombotic diseases.


Assuntos
Plaquetas , Vesículas Extracelulares , NADPH Oxidase 1/genética , NADPH Oxidases , Ativação Plaquetária , Espécies Reativas de Oxigênio , Superóxidos
15.
Scand J Gastroenterol ; 55(11): 1309-1317, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33070650

RESUMO

BACKGROUND: As data is limited on the outcomes of calcineurin inhibitors (CNI) in autoimmune hepatitis (AIH), we evaluated the efficacy and safety of CNI in AIH patients who failed prior treatment(s). METHODS: A retrospective study was performed of AIH patients who received cyclosporine A (CsA) and/or tacrolimus (TAC) after prior treatment(s) failure. Records were reviewed for baseline demographic and clinical characteristics, and treatment outcomes. The primary outcome was biochemical remission.Results: Thirty-three AIH patients received CNI across seven liver centers:17 received CsA, 21 TAC and 5 TAC after CsA failure/intolerance. 82% received CNI for an insufficient response to treatment(s). Overall, 48% of CNI treated patients achieved biochemical remission including 41% in prior non-responders and 83% in treatment intolerant patients. Remission rates with CNI as second-line and third-line therapy were 63% and 29% respectively. There were no baseline predictors of response to CNI on multivariate analysis. Eighteen (55%) patients developed significant side effects and 8 (24%) discontinued due to intolerance. Three patients required liver transplantation for decompensated cirrhosis and 6 patients died including one from malignancy possibly related to CNI. CONCLUSION: CNI salvage therapy is well tolerated and moderately effective achieving remission in around 50% of AIH who failed standard therapy.


Assuntos
Inibidores de Calcineurina , Hepatite Autoimune , Ciclosporina/efeitos adversos , Hepatite Autoimune/tratamento farmacológico , Humanos , Imunossupressores/efeitos adversos , Estudos Retrospectivos , Terapia de Salvação , Tacrolimo/efeitos adversos , Resultado do Tratamento
16.
Nurse Educ Today ; 92: 104429, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32593856

RESUMO

BACKGROUND: Undergraduate nursing students are participating in part-time employment to finance their way through their studies despite evidence that working while undertaking study negatively impacts on their academic performance. METHOD: A mixed method research design was used to collect data for this study. Thematic analysis was used to analyse the data. The survey was completed by 58 students enrolled in a three-year Bachelor of Nursing (BN) programme across two campuses at Toi Ohomai Institute of Technology in the Bay of Plenty, New Zealand. RESULTS: Findings from this study showed student nurses undertake part-time work to reduce financial hardship and avoid student debt. Students reported their employment whether it be in health care, retail or hospitality, provided them with skills to support their nursing studies. An important finding was irrespective of the number of hours worked, students reported their work impacted negatively on their academic success as it diminished the amount of time they had to study. CONCLUSION: Although this is a small-scale study, the results provide valuable insight into nursing students' perceptions of the influence of paid employment on their academic success within the nursing programme. This research has national and international relevance given there is evidence that significant numbers of nursing students across many countries participate in part-time employment to reduce financial hardship and avoid excessive debt.


Assuntos
Bacharelado em Enfermagem , Estudantes de Enfermagem , Emprego , Humanos , Nova Zelândia , Percepção , Inquéritos e Questionários
17.
J Thromb Haemost ; 18(7): 1548-1555, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32329246

RESUMO

The global pandemic of coronavirus disease 2019 (COVID-19) is associated with the development of acute respiratory distress syndrome (ARDS), which requires ventilation in critically ill patients. The pathophysiology of ARDS results from acute inflammation within the alveolar space and prevention of normal gas exchange. The increase in proinflammatory cytokines within the lung leads to recruitment of leukocytes, further propagating the local inflammatory response. A consistent finding in ARDS is the deposition of fibrin in the air spaces and lung parenchyma. COVID-19 patients show elevated D-dimers and fibrinogen. Fibrin deposits are found in the lungs of patients due to the dysregulation of the coagulation and fibrinolytic systems. Tissue factor (TF) is exposed on damaged alveolar endothelial cells and on the surface of leukocytes promoting fibrin deposition, while significantly elevated levels of plasminogen activator inhibitor 1 (PAI-1) from lung epithelium and endothelial cells create a hypofibrinolytic state. Prophylaxis treatment of COVID-19 patients with low molecular weight heparin (LMWH) is important to limit coagulopathy. However, to degrade pre-existing fibrin in the lung it is essential to promote local fibrinolysis. In this review, we discuss the repurposing of fibrinolytic drugs, namely tissue-type plasminogen activator (tPA), to treat COVID-19 associated ARDS. tPA is an approved intravenous thrombolytic treatment, and the nebulizer form has been shown to be effective in plastic bronchitis and is currently in Phase II clinical trial. Nebulizer plasminogen activators may provide a targeted approach in COVID-19 patients to degrade fibrin and improving oxygenation in critically ill patients.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/tratamento farmacológico , Fibrinólise/efeitos dos fármacos , Fibrinolíticos/administração & dosagem , Pneumonia Viral/tratamento farmacológico , Terapia Trombolítica , Ativador de Plasminogênio Tecidual/administração & dosagem , COVID-19 , Infecções por Coronavirus/sangue , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Reposicionamento de Medicamentos , Fibrinolíticos/efeitos adversos , Interações Hospedeiro-Patógeno , Humanos , Pandemias , Pneumonia Viral/sangue , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia , SARS-CoV-2 , Terapia Trombolítica/efeitos adversos , Ativador de Plasminogênio Tecidual/efeitos adversos , Resultado do Tratamento , Tratamento Farmacológico da COVID-19
19.
Lancet Infect Dis ; 19(7): 770-777, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31196812

RESUMO

BACKGROUND: Legionnaires' disease is under-diagnosed because of inconsistent use of diagnostic tests and uncertainty about whom to test. We assessed the increase in case detection following large-scale introduction of routine PCR testing of respiratory specimens in New Zealand. METHODS: LegiNZ was a national surveillance study done over 1-year in which active case-finding was used to maximise the identification of cases of Legionnaires' disease in hospitals. Respiratory specimens from patients of any age with pneumonia, who could provide an eligible lower respiratory specimen, admitted to one of 20 participating hospitals, covering a catchment area of 96% of New Zealand's population, were routinely tested for legionella by PCR. Additional cases of Legionnaires' disease in hospital were identified through mandatory notification. FINDINGS: Between May 21, 2015, and May 20, 2016, 5622 eligible specimens from 4862 patients were tested by PCR. From these, 197 cases of Legionnaires' disease were detected. An additional 41 cases were identified from notification data, giving 238 cases requiring hospitalisation. The overall incidence of Legionnaires' disease cases in hospital in the study area was 5·4 per 100 000 people per year, and Legionella longbeachae was the predominant cause, found in 150 (63%) of 238 cases. INTERPRETATION: The rate of notified disease during the study period was three-times the average over the preceding 3 years. Active case-finding through systematic PCR testing better clarified the regional epidemiology of Legionnaires' disease and uncovered an otherwise hidden burden of disease. These data inform local Legionnaires' disease testing strategies, allow targeted antibiotic therapy, and help identify outbreaks and effective prevention strategies. The same approach might have similar benefits if applied elsewhere in the world. FUNDING: Health Research Council of New Zealand.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Doença dos Legionários/diagnóstico , Doença dos Legionários/epidemiologia , Vigilância da População , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Notificação de Doenças , Feminino , Humanos , Incidência , Legionella pneumophila/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Nova Zelândia/epidemiologia , Reação em Cadeia da Polimerase , Adulto Jovem
20.
Aliment Pharmacol Ther ; 49(10): 1314-1322, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30972807

RESUMO

BACKGROUND: Mycophenolate mofetil is a commonly used salvage therapy for patients with autoimmune hepatitis (AIH). AIM: To evaluate the predictors of response to mycophenolate rescue therapy to facilitate clinical decision making. METHODS: We performed a retrospective observational cohort study of AIH patients managed in 17 major Australian liver centres who received mycophenolate after an inadequate response or intolerance to corticosteroids with/without thiopurine(s). Baseline demographic, clinical and laboratory variables were compared between responders and nonresponders. A multivariable logistic regression model was developed using forward selection to identify independent predictors of treatment response. RESULTS: A total of 105 patients received mycophenolate rescue therapy of whom 63 (60%) achieved biochemical remission. On univariable analysis, older age (P = 0.003), INR < 1.1 (P = 0.02), and lower immunoglobulin gamma (IgG; P < 0.002) levels were associated with treatment response, while no association was found with cirrhosis status (P = 0.07) or treatment indication (P = 0.63). On multivariable analysis, lower pre-treatment serum IgG level (P = 0.01), higher age at commencing mycophenolate (P = 0.01) and higher INR (P = 0.03) were the only significant independent predictors. An IgG level <17 g/L had a positive and negative predictive value for response of 71% and 60% respectively, while age ≥54 years when commencing mycophenolate had a positive and negative predictive value for response of 80% and 59% respectively. CONCLUSION: Mycophenolate remains an excellent treatment option for patients with AIH refractory to or intolerant of standard therapy with those most likely to benefit being older and/or having lower pre-treatment IgG levels.


Assuntos
Hepatite Autoimune/tratamento farmacológico , Ácido Micofenólico/uso terapêutico , Corticosteroides/uso terapêutico , Adulto , Fatores Etários , Feminino , Hepatite Autoimune/sangue , Humanos , Imunoglobulina G/sangue , Coeficiente Internacional Normatizado , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Terapia de Salvação , Resultado do Tratamento
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