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This cross-sectional study surveyed veterinarians and facility managers to characterise the use of antimicrobials in laboratory rodent facilities within Australia and New Zealand. Most facilities (71%) reported routine administration of antimicrobials. The indications for antibiotic use reflected those described in publications and differed significantly to reasons for use in non-laboratory animals. Antimicrobials used include those of critical importance to human health, and access to these drugs is unregulated, as prescription-only classes are ordered through research catalogues, without human or veterinary physician prescriptions. The ways in which antimicrobials are used in Australian and New Zealand rodent facilities are likely contributing to antimicrobial resistance within rodent populations, particularly as they are largely administered in drinking water, risking subtherapeutic dosing. Much antimicrobial use reported is unnecessary and could be replaced with changes to husbandry and handling. The generation of resistance in both pathogenic and commensal microbes may also represent a work health and safety issue for humans working with these animals. Reported disposal of antimicrobials included discharge into wastewater, without inactivation, and some respondents reported disposal of substrate, or soiled bedding, nesting material, and disposable enrichment items, from treated animals and medicated feed into landfill, without prior inactivation. Environmental contamination with resistant microbes and antimicrobials is a significant driver of antimicrobial resistance. As such, significant opportunities exist to implement judicious and responsible use of antimicrobials within research rodent facilities in Australia and New Zealand, with a particular focus on instituting aseptic surgery, optimising dosing regimens, and inactivation of medicated water and substrate before disposal.
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Médicos Veterinários , Nova Zelândia , Animais , Austrália , Estudos Transversais , Humanos , Inquéritos e Questionários , Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/uso terapêutico , Criação de Animais Domésticos/métodos , Animais de Laboratório , Antibacterianos/uso terapêutico , Antibacterianos/administração & dosagem , RoedoresRESUMO
Multisystem inflammatory syndrome in children (MIS-C) is a severe, post-infectious sequela of SARS-CoV-2 infection1,2, yet the pathophysiological mechanism connecting the infection to the broad inflammatory syndrome remains unknown. Here we leveraged a large set of samples from patients with MIS-C to identify a distinct set of host proteins targeted by patient autoantibodies including a particular autoreactive epitope within SNX8, a protein involved in regulating an antiviral pathway associated with MIS-C pathogenesis. In parallel, we also probed antibody responses from patients with MIS-C to the complete SARS-CoV-2 proteome and found enriched reactivity against a distinct domain of the SARS-CoV-2 nucleocapsid protein. The immunogenic regions of the viral nucleocapsid and host SNX8 proteins bear remarkable sequence similarity. Consequently, we found that many children with anti-SNX8 autoantibodies also have cross-reactive T cells engaging both the SNX8 and the SARS-CoV-2 nucleocapsid protein epitopes. Together, these findings suggest that patients with MIS-C develop a characteristic immune response to the SARS-CoV-2 nucleocapsid protein that is associated with cross-reactivity to the self-protein SNX8, demonstrating a mechanistic link between the infection and the inflammatory syndrome, with implications for better understanding a range of post-infectious autoinflammatory diseases.
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Anticorpos Antivirais , Autoanticorpos , COVID-19 , Reações Cruzadas , Epitopos , Mimetismo Molecular , SARS-CoV-2 , Síndrome de Resposta Inflamatória Sistêmica , Criança , Humanos , Anticorpos Antivirais/imunologia , Autoanticorpos/imunologia , Proteínas do Nucleocapsídeo de Coronavírus/química , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , COVID-19/imunologia , COVID-19/virologia , COVID-19/complicações , Reações Cruzadas/imunologia , Epitopos/imunologia , Epitopos/química , Mimetismo Molecular/imunologia , Fosfoproteínas/química , Fosfoproteínas/imunologia , SARS-CoV-2/química , SARS-CoV-2/imunologia , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidade , Nexinas de Classificação/química , Nexinas de Classificação/imunologia , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Síndrome de Resposta Inflamatória Sistêmica/patologia , Síndrome de Resposta Inflamatória Sistêmica/virologia , Linfócitos T/imunologiaRESUMO
OBJECTIVE: Although point of care ultrasound (POCUS) use has become prevalent in medicine, clinicians may not be familiar with the evidence supporting its utility in patient care. The objective of this study is to identify the top five most influential papers published on the use of cardiac POCUS and lung POCUS in adult patients. METHODS: A 14-member expert panel from the Canadian Association of Emergency Physicians (CAEP) Emergency Ultrasound Committee and the Canadian Ultrasound Fellowship Collaborative used a modified Delphi process. Panel members are ultrasound fellowship trained or equivalent, are engaged in POCUS scholarship, and are leaders in POCUS locally and nationally in Canada. The modified Delphi process consisted of three rounds of sequential surveys and discussion to achieve consensus on the top five most influential papers on cardiac POCUS and lung POCUS. RESULTS: A total of 66 relevant papers on cardiac POCUS and 68 relevant papers on lung POCUS were nominated by the panel. There was 100% participation by the panel members in all three rounds of the modified Delphi process. At the end of this process, we identified the top five most influential papers on cardiac POCUS and lung POCUS. Papers include studies supporting the use of POCUS for accurately assessing left ventricular systolic function, diagnosing pericardial effusion, clarifying its test characteristics for pulmonary embolism, identifying pulmonary edema and pneumonia, as well as consensus statements on the use of cardiac and lung POCUS in clinical practice. CONCLUSION: We have created a list of the top five influential papers on cardiac POCUS and lung POCUS as an evidence-based resource for trainees, clinicians, and researchers. This will help trainees and clinicians better understand how to use POCUS when scanning the heart and lungs, and it will also help researchers better understand where to direct their scholarly efforts with future research.
RéSUMé: OBJECTIF: Bien que l'utilisation de l'échographie par point de soins (POCUS) soit devenue courante en médecine, les cliniciens ne sont peut-être pas familiarisés avec les données probantes qui appuient son utilité dans les soins aux patients. Cette étude a pour objectif d'identifier les cinq articles les plus influents publiés sur l'utilisation de la POCUS cardiaque et pulmonaire chez des patients adultes. MéTHODES: Un groupe d'experts composé de 14 membres du Comité des échographies d'urgence de l'Association canadienne des médecins d'urgence (ACEP) et du Canadian Ultrasound Fellowship Collaborative a utilisé un processus Delphi modifié. Les membres du comité sont des stagiaires en échographie ou l'équivalent, ils participent à des activités de recherche sur le POCUS et sont des chefs de file au niveau local et national au Canada. Le processus Delphi modifié consistait en trois rondes de sondages séquentiels et de discussions pour parvenir à un consensus sur les cinq articles les plus influents sur la POCUS cardiaque et la POCUS pulmonaire. RéSULTATS: Le panel a proposé un total de 66 articles pertinents sur la POCUS cardiaque et 68 documents pertinents sur la POCUS pulmonaire. Les membres du groupe ont participé à 100 % aux trois rondes du processus Delphi modifié. À la fin de ce processus, nous avons identifié les cinq principaux articles les plus influents sur le POCUS cardiaque et le POCUS pulmonaire. Les articles comprennent des études soutenant l'utilisation de POCUS pour évaluer avec précision la fonction systolique du ventricule gauche, diagnostiquer le épanchement péricardique, clarifier ses caractéristiques de test pour l'embolie pulmonaire, identifier l'Ådème pulmonaire et la pneumonie, ainsi que des déclarations de consensus sur l'utilisation du POCUS cardiaque et pulmonaire dans la pratique clinique. CONCLUSION: Nous avons dressé une liste des cinq principaux articles influents sur le POCUS cardiaque et le POCUS pulmonaire en tant que ressource fondée sur des données probantes pour les stagiaires, les cliniciens et les chercheurs. Cela aidera les stagiaires et les cliniciens à mieux comprendre comment utiliser le POCUS pour scanner le cÅur et les poumons, et cela aidera également les chercheurs à mieux comprendre où orienter leurs efforts scientifiques dans la recherche future.
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BACKGROUND: Many studies highlight poor health-related quality of life (HRQoL) in children treated for brain tumours and their parents. However, little is known about the extent to which their informational, healthcare and communication needs regarding HRQoL are met during medical outpatient consultations. AIM: To explore the experiences of families regarding communication with physicians about HRQoL issues during consultations after treatment for childhood brain tumours. METHODS: Interviews were conducted with 18 families of children and adolescents aged 8-17 years after completion of brain tumour treatment. Participants had completed treatment within the last 5 years and were receiving regular outpatient follow-up care. Thematic analysis was undertaken using the Framework Method. RESULTS: Five main themes were identified: (i) unmet emotional and mental health needs; (ii) double protection; (iii) unmet information needs; (iv) communication barriers within consultations; and (v) finding a new normal. CONCLUSION: There was a need to improve communication between clinicians and these families, improve information provision, and overcome barriers to conversing with children within these outpatient consultations. Children and their parents should be supported to voice their current needs and concerns regarding their HRQoL. These findings will inform further development of the UK version of the 'KLIK' patient- and parent-reported outcome (PROM) portal.
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Vaccines and first-generation antiviral therapeutics have provided important protection against COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, there remains a need for additional therapeutic options that provide enhanced efficacy and protection against potential viral resistance. The SARS-CoV-2 papain-like protease (PLpro) is one of the two essential cysteine proteases involved in viral replication. While inhibitors of the SARS-CoV-2 main protease have demonstrated clinical efficacy, known PLpro inhibitors have, to date, lacked the inhibitory potency and requisite pharmacokinetics to demonstrate that targeting PLpro translates to in vivo efficacy in a preclinical setting. Here, we report the machine learning-driven discovery of potent, selective, and orally available SARS-CoV-2 PLpro inhibitors, with lead compound PF-07957472 (4) providing robust efficacy in a mouse-adapted model of COVID-19 infection.
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Antivirais , Tratamento Farmacológico da COVID-19 , Proteases Semelhantes à Papaína de Coronavírus , Modelos Animais de Doenças , SARS-CoV-2 , Animais , Camundongos , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , Antivirais/química , Antivirais/farmacocinética , Antivirais/uso terapêutico , Proteases Semelhantes à Papaína de Coronavírus/antagonistas & inibidores , Proteases Semelhantes à Papaína de Coronavírus/metabolismo , Humanos , COVID-19/virologia , Inibidores de Proteases/farmacologia , Inibidores de Proteases/química , Inibidores de Proteases/uso terapêutico , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/metabolismo , Aprendizado de Máquina , Feminino , Replicação Viral/efeitos dos fármacosRESUMO
We have identified the most relevant and significant psychological factors in relation to COVID-19 vaccination attitudes in Ghana, Germany, New Zealand and India. This study recruited 1822 participants from the general populations of India (n = 411), New Zealand (n = 413), Ghana (n = 523) and Germany (n = 475) to participate in a cross-sectional online survey. After controlling for the country of residence, individual psychological factors played a significant role in shaping attitudes towards COVID-19 vaccination. The results also revealed strong direct predictors that explained significant portions of the variance in the COVID-19 vaccination attitudes. Positive affect emerged as the strongest contributor in Ghana (7%), while self-compassion strongly influenced COVID-19 vaccination attitudes in India (66%). Dispositional optimism was the strongest predictor in New Zealand (5%). In Germany, compassion towards others was the strongest positive predictor (2%), while psychological distress had a strong negative impact (3%). Results highlight the importance of promoting emotional well-being to enhance vaccination coverage.
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BACKGROUND: Mucopolysaccharidosis (MPS) type IVA is a rare lysosomal storage disorder caused by aberrations of the N-acetyl-galactosamine-6-sulfatase (GALNS) enzyme. MPS IVA is associated with a wide gamut of respiratory and airway disorders that manifest in a continuum of severity. In individuals exhibiting severe phenotypic expression, terminal stages of the disease frequently culminate in life-threatening, critical airway obstruction. These manifestations of end-stage disease are engendered by an insidious progression of multi-level airway pathologies, comprising of tracheomalacia, stenosis, tortuosity and 'buckling'. Historically, the management of end-stage airway disease has predominantly leaned towards palliative modalities. However, contemporary literature has posited that the potential benefits of tracheal resection with aortopexy, performed under cardiopulmonary bypass (CPB), may offer a promising therapeutic option. In this context, we report on outcomes from patients undergoing a novel approach to tracheal resection that is combined with manubrial resection, leading to improved airway calibre, obviating the requisition for CPB. RESULTS: In this study, seven patients with severe MPS IVA exhibited clinical symptoms and radiological evidence indicative of advanced airway obstruction. All patients had a tracheal resection with a partial upper manubriectomy via transcervical approach, which did not require CPB. The surgical cohort consisted of 5 females and 2 males, the median age was 16 years (range 11-19) and the median height was 105.6cm (range 96.4-113.4). Postoperatively, significant improvements were seen in forced expiratory volume in 1 second (FEV1), with a mean increase of 0.68 litres (95% CI: 0.45-0.91; SD: 0.20). Notably, other spirometry variables also showed meaningful improvements, providing evidence of positive treatment effects. Furthermore, there were no major long-term complications, and the procedure resulted in a significant enhancement in patient-reported domains using PedsQL (version 4.0). CONCLUSIONS: This study represents the largest case series to date, on tracheal resection in patients with severe MPS IVA. Our findings demonstrate the effectiveness of the transcervical approach with partial manubriectomy for improving respiratory function and quality of life for individuals with advanced airway obstruction. Tracheal resection presents a promising treatment modality for severe cases of MPS IVA. Successful outcomes rely on meticulous multidisciplinary assessment, judicious decision-making, and appropriate timing of tracheal surgery. Further research and long-term follow-up studies are warranted to validate the long-term efficacy and safety of this approach.
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Obstrução das Vias Respiratórias , Mucopolissacaridose IV , Traqueia , Humanos , Mucopolissacaridose IV/cirurgia , Feminino , Masculino , Obstrução das Vias Respiratórias/cirurgia , Traqueia/cirurgia , Adolescente , Criança , Adulto Jovem , Reino Unido , AdultoRESUMO
In this article we review the history of key epidemiological studies of populations exposed to ionizing radiation. We highlight historical and recent findings regarding radiation-associated risks for incidence and mortality of cancer and non-cancer outcomes with emphasis on study design and methods of exposure assessment and dose estimation along with brief consideration of sources of bias for a few of the more important studies. We examine the findings from the epidemiological studies of the Japanese atomic bomb survivors, persons exposed to radiation for diagnostic or therapeutic purposes, those exposed to environmental sources including Chornobyl and other reactor accidents, and occupationally exposed cohorts. We also summarize results of pooled studies. These summaries are necessarily brief, but we provide references to more detailed information. We discuss possible future directions of study, to include assessment of susceptible populations, and possible new populations, data sources, study designs and methods of analysis.
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Neoplasias Induzidas por Radiação , Exposição à Radiação , Radiação Ionizante , Humanos , Exposição à Radiação/efeitos adversos , Neoplasias Induzidas por Radiação/epidemiologia , Neoplasias Induzidas por Radiação/etiologia , História do Século XX , Estudos Epidemiológicos , História do Século XXI , Exposição OcupacionalRESUMO
Examining underlying neurostructural correlates of specific cognitive abilities is practically and theoretically complicated by the existence of the positive manifold (all cognitive tests positively correlate): if a brain structure is associated with a cognitive task, how much of this is uniquely related to the cognitive domain, and how much is due to covariance with all other tests across domains (captured by general cognitive functioning, also known as general intelligence, or 'g')? We quantitatively address this question by examining associations between brain structural and diffusion MRI measures (global tissue volumes, white matter hyperintensities, global white matter diffusion fractional anisotropy and mean diffusivity, and FreeSurfer processed vertex-wise cortical volumes, smoothed at 20mm fwhm) with g and cognitive domains (processing speed, crystallised ability, memory, visuospatial ability). The cognitive domains were modelled using confirmatory factor analysis to derive both hierarchical and bifactor solutions using 13 cognitive tests in 697 participants from the Lothian Birth Cohort 1936 study (mean age 72.5 years; SD = .7). Associations between the extracted cognitive factor scores for each domain and g were computed for each brain measure covarying for age, sex and intracranial volume, and corrected for false discovery rate. There were a range of significant associations between cognitive domains and global MRI brain structural measures (r range .008 to .269, p < .05). Regions implicated by vertex-wise regional cortical volume included a widespread number of medial and lateral areas of the frontal, temporal and parietal lobes. However, at both global and regional level, much of the domain-MRI associations were shared (statistically accounted for by g). Removing g-related variance from cognitive domains attenuated association magnitudes with global brain MRI measures by 27.9-59.7% (M = 46.2%), with only processing speed retaining all significant associations. At the regional cortical level, g appeared to account for the majority (range 22.1-88.4%; M = 52.8% across cognitive domains) of regional domain-specific associations. Crystallised and memory domains had almost no unique cortical correlates, whereas processing speed and visuospatial ability retained limited cortical volumetric associations. The greatest spatial overlaps across cognitive domains (as denoted by g) were present in the medial and lateral temporal, lateral parietal and lateral frontal areas.
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Encéfalo , Cognição , Inteligência , Humanos , Feminino , Inteligência/fisiologia , Masculino , Idoso , Encéfalo/diagnóstico por imagem , Encéfalo/anatomia & histologia , Cognição/fisiologia , Testes Neuropsicológicos , Coorte de Nascimento , Substância Branca/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Estudos de CoortesRESUMO
OBJECTIVES: The objective was to measure health-related quality of life (HRQoL) of children following treatment of all-cause tracheomalacia with aortopexy. METHODS: Children ≥5 years and parents of children <18 years who had undergone aortopexy completed the Paediatric Quality of Life Inventory (PedsQL4.0). Scores were compared to published norms. RESULTS: Completed questionnaires were received from 35 parents (65%) and 10 children (38%). Median age at aortopexy was 9.8 months (1 month-12.7 years) and median years of follow-up was 2.6 (4 months-6.9 years). Children who completed questionnaires had a median age of 8.4 (5.7-13.4) years. Parent and child-reported total PedsQL scores were 69.61 (SD : 19.74), and 63.15 (SD : 20.40) respectively. Half of parents and 80% of children reported scores suggesting poor HRQoL outcomes. Parent-reported total, physical and psycho-social scores were lower than those of healthy children and those with acute illness but comparable to children with chronic health conditions and cardiovascular disease. Similarly, children themselves reported comparable total scores to children with chronic illness but child-reported psycho-social scores were lower in the aortopexy group than any other group. There was no association between PedsQL scores and cause of malacia, age or time since aortopexy. The presence of complex congenital comorbidities had a significant (p < 0.05) impact on HRQoL scores. CONCLUSIONS: Following aortopexy children remain at risk of poor HRQoL, especially those with complex comorbidities. HRQoL reported by both parent and child provides important insight into the lives of children following this procedure. Further longitudinal and qualitative study are required to better understand this complex group.
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BACKGROUND: Measurement of the efficacy of the networks of attention is a frequent component of research in cognitive and clinical neuroscience. Developed in 2002, the Attention Network Test (ANT), has become the most widely used tool for this purpose. NEW METHOD: In 2017 a more engaging, game-like tool based on the ANT, called the AttentionTrip was described. The network scores from five studies which used AttentionTrip are shown to be robust. NEWER METHOD: That version of AttentionTrip required a steering wheel and desk-top computer. Here we describe a new, portable version of the AttentionTrip that is administered using a hand-held tablet (iPad) RESULTS: Three samples of participants (total = 44) completed the portable version of AttentionTrip. The network scores generated using the portable AttentionTrip were also robust. Effect sizes compare favourably with those generated by the ANT and the desktop version. CONCLUSIONS: The findings support the use of the portable AttentionTrip as an alternative to the ANT when user engagement is important, such as when participants are prone to boredom, and when repeated administrations are required.
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Atenção , Humanos , Atenção/fisiologia , Masculino , Feminino , Adulto , Adulto Jovem , Testes Neuropsicológicos , Computadores de Mão , AdolescenteRESUMO
People with multiple sclerosis (PwMS) who report dizziness often have gaze instability due to vestibulo-ocular reflex (VOR) deficiencies and compensatory saccade (CS) abnormalities. Herein, we aimed to describe and compare the gaze stabilization mechanisms for yaw and pitch head movements in PwMS. Thirty-seven PwMS (27 female, mean ± SD age = 53.4 ± 12.4 years old, median [IQR] Expanded Disability Status Scale Score = 3.5, [1.0]. We analyzed video head impulse test results for VOR gain, CS frequency, CS latency, gaze position error (GPE) at impulse end, and GPE at 400 ms after impulse start. Discrepancies were found for median [IQR] VOR gain in yaw (0.92 [0.14]) versus pitch-up (0.71 [0.44], p < 0.001) and pitch-down (0.81 [0.44], p = 0.014]), CS latency in yaw (258.13 [76.8]) ms versus pitch-up (208.78 [65.97]) ms, p = 0.001] and pitch-down (132.17 [97.56] ms, p = 0.006), GPE at impulse end in yaw (1.15 [1.85] degs versus pitch-up (2.71 [3.9] degs, p < 0.001), and GPE at 400 ms in yaw (-0.25 [0.98] degs) versus pitch-up (1.53 [1.07] degs, p < 0.001) and pitch-down (1.12 [1.82] degs, p = 0.001). Compared with yaw (0.91 [0.75]), CS frequency was similar for pitch-up (1.03 [0.93], p = 0.999) but lower for pitch-down (0.65 [0.64], p = 0.023). GPE at 400 ms was similar for yaw and pitch-down (1.88 [2.76] degs, p = 0.400). We postulate that MS may have preferentially damaged the vertical VOR and saccade pathways in this cohort.
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Esclerose Múltipla , Reflexo Vestíbulo-Ocular , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/complicações , Adulto , Reflexo Vestíbulo-Ocular/fisiologia , Idoso , Fixação Ocular/fisiologia , Movimentos da Cabeça/fisiologia , Movimentos Sacádicos/fisiologia , Teste do Impulso da Cabeça/métodosRESUMO
Several population-level studies have described individual clinical risk factors associated with suboptimal antibody responses following COVID-19 vaccination, but none have examined multimorbidity. Others have shown that suboptimal post-vaccination responses offer reduced protection to subsequent SARS-CoV-2 infection; however, the level of protection from COVID-19 hospitalisation/death remains unconfirmed. We use national Scottish datasets to investigate the association between multimorbidity and testing antibody-negative, examining the correlation between antibody levels and subsequent COVID-19 hospitalisation/death among double-vaccinated individuals. We found that individuals with multimorbidity ( ≥ five conditions) were more likely to test antibody-negative post-vaccination and 13.37 [6.05-29.53] times more likely to be hospitalised/die from COVID-19 than individuals without conditions. We also show a dose-dependent association between post-vaccination antibody levels and COVID-19 hospitalisation or death, with those with undetectable antibody levels at a significantly higher risk (HR 9.21 [95% CI 4.63-18.29]) of these serious outcomes compared to those with high antibody levels.
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We report the preparation of a co-crystal formed between the energetic molecule 3-nitro-1,2,4-triazol-5-one (NTO) and 4,4'-bipyridine (BIPY), that has been structurally characterised by high-pressure single crystal and neutron powder diffraction data up to 5.93 GPa. No phase transitions or proton transfer were observed up to this pressure. At higher pressures the crystal quality degraded and the X-ray diffraction patterns showed severe twinning, with the appearance of multiple crystalline domains. Computational modelling indicates that the colour changes observed on application of pressure can be attributed to compression of the unit cell that cause heightened band dispersion and band gap narrowing that coincides with a shortening of the BIPY πâ¯π stacking distance. Modelling also suggests that the application of pressure induces proton migration along an N-Hâ¯N intermolecular hydrogen bond. Impact-sensitivity measurements show that the co-crystal is less sensitive to initiation than NTO, whereas computational modelling suggests that the impact sensitivities of NTO and the co-crystal are broadly similar.
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Phosphorylation of histone H3 threonine 3 (H3T3) by Haspin recruits the chromosomal passenger complex to the inner centromere and ensures proper cell cycle progression through mitosis. The mechanism by which Haspin binds to nucleosomes to phosphorylate H3T3 is not known. We report here cryo-EM structures of the Haspin kinase domain bound to a nucleosome. In contrast with previous structures of histone-modifying enzymes, Haspin solely contacts the nucleosomal DNA, inserting into a supergroove formed by apposing major grooves of two DNA gyres. This unique binding mode provides a plausible mechanism by which Haspin can bind to nucleosomes in a condensed chromatin environment to phosphorylate H3T3. We identify key basic residues in the Haspin kinase domain that are essential for phosphorylation of nucleosomal histone H3 and binding to mitotic chromatin. Our structure is the first of a kinase domain bound to a nucleosome and is the first example of a histone-modifying enzyme that binds to nucleosomes solely through DNA contacts.
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Cytochromes c'-α are nitric oxide (NO)-binding heme proteins derived from bacteria that can thrive in a wide range of temperature environments. Studies of mesophilic Alcaligenes xylosoxidans cytochrome c'-α (AxCP-α) have revealed an unusual NO-binding mechanism involving both heme faces, in which NO first binds to form a distal hexa-coordinate Fe(II)-NO (6cNO) intermediate and then displaces the proximal His to form a proximal penta-coordinate Fe(II)-NO (5cNO) final product. Here, we characterize a thermally stable cytochrome c'-α from thermophilic Hydrogenophilus thermoluteolus (PhCP-α) to understand how protein thermal stability affects NO binding. Electron paramagnetic and resonance Raman spectroscopies reveal the formation of a PhCP-α 5cNO product, with time-resolved (stopped-flow) UV-vis absorbance indicating the involvement of a 6cNO intermediate. Relative to AxCP-α, the rates of 6cNO and 5cNO formation in PhCP-α are â¼11- and â¼13-fold lower, respectively. Notably, x-ray crystal structures of PhCP-α in the presence and absence of NO suggest that the sluggish formation of the proximal 5cNO product results from conformational rigidity: the Arg-132 residue (adjacent to the proximal His ligand) is held in place by a salt bridge between Arg-75 and Glu-135 (an interaction not present in AxCP-α or a psychrophilic counterpart). Overall, our data provide fresh insights into structural factors controlling NO binding in heme proteins, including 5cNO complexes relevant to eukaryotic NO sensors.
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Citocromos c' , Óxido Nítrico , Ligação Proteica , Óxido Nítrico/metabolismo , Óxido Nítrico/química , Citocromos c'/química , Citocromos c'/metabolismo , Conformação Proteica , Hydrogenophilaceae/enzimologia , Hydrogenophilaceae/metabolismo , Hydrogenophilaceae/química , Temperatura , Modelos Moleculares , CinéticaRESUMO
Most cancers are diagnosed in persons over the age of sixty, but little is known about how age impacts tumorigenesis. While aging is accompanied by mutation accumulation - widely understood to contribute to cancer risk - it is also associated with numerous other cellular and molecular changes likely to impact tumorigenesis. Moreover, cancer incidence decreases in the oldest part of the population, suggesting that very old age may reduce carcinogenesis. Here we show that aging represses tumor initiation and growth in genetically engineered mouse models of human lung cancer. Moreover, aging dampens the impact of inactivating many, but not all, tumor suppressor genes with the impact of inactivating PTEN, a negative regulator of the PI3K/AKT pathway, weakened to a disproportionate extent. Single-cell transcriptomic analysis revealed that neoplastic cells from tumors in old mice retain many age-related transcriptomic changes, showing that age has an enduring impact that persists through oncogenic transformation. Furthermore, the consequences of PTEN inactivation were strikingly age-dependent, with PTEN deficiency reducing signatures of aging in cancer cells and the tumor microenvironment. Our findings suggest that the relationship between age and lung cancer incidence may reflect an integration of the competing effects of driver mutation accumulation and tumor suppressive effects of aging.
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Recurrent depression with psychotic features is an atypical presentation of neurosyphilis. This case emphasizes the polymorphic clinical presentation of neurosyphilis and how it mimics affective disorders with psychotic symptoms.