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1.
Mol Cell ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38955179

RESUMO

The specific nature of CRISPR-Cas12a makes it a desirable RNA-guided endonuclease for biotechnology and therapeutic applications. To understand how R-loop formation within the compact Cas12a enables target recognition and nuclease activation, we used cryo-electron microscopy to capture wild-type Acidaminococcussp. Cas12a R-loop intermediates and DNA delivery into the RuvC active site. Stages of Cas12a R-loop formation-starting from a 5-bp seed-are marked by distinct REC domain arrangements. Dramatic domain flexibility limits contacts until nearly complete R-loop formation, when the non-target strand is pulled across the RuvC nuclease and coordinated domain docking promotes efficient cleavage. Next, substantial domain movements enable target strand repositioning into the RuvC active site. Between cleavage events, the RuvC lid conformationally resets to occlude the active site, requiring re-activation. These snapshots build a structural model depicting Cas12a DNA targeting that rationalizes observed specificity and highlights mechanistic comparisons to other class 2 effectors.

2.
Med Teach ; : 1-8, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38963305

RESUMO

Since 1991, there have been significant changes in medical education in Georgia. Key changes include adapting national legislation toward international standards, establishing the National Center for Education Quality Enhancement (NCEQE), which was recognized in 2018 by the World Federation for Medical Education (WFME) as an accrediting agency and opening the Association for Medical Education in Europe (AMEE) International Networking Center in 2019. Undergraduate medical education, regulated by the Ministry of Education, Science and Youth of Georgia, spans six years. MD graduates then have options for further career paths, including working as junior doctors, residency, and/or pursuing PhD research.The main challenges the country presently faces are:the need to reduce the increasing number of (mainly) private medical schools. Recent updates to the national standards for undergraduate medical education have imposed stricter accreditation requirements for MD programs, resulting in the closure of schools that fail to meet these standards;postgraduate medical education is governed by the Ministry of Internally Displaced Persons from the Occupied Territories, Labor, Health and Social Affairs of Georgia (MOH) and needs further reform due to limited and paid residency positions;continuous professional development (CPD) was optional until recently, which led to an increase in professional inaccuracy and malpractice cases. To address this, regulatory bodies, including the MOH and professional associations, are preparing the legal basis for introducing compulsory CPD.

3.
J Psychopharmacol ; : 2698811241262767, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39041349

RESUMO

BACKGROUND: Clozapine is known to cause agranulocytosis. Mandatory monitoring schemes are aimed at reducing the risk of agranulocytosis and of the consequences of agranulocytosis. All cases of agranulocytosis occurring in people prescribed clozapine are assumed to be caused by clozapine. METHODS: In a previous study, we examined a cohort of patients listed on our hospital database as having had clozapine-induced agranulocytosis and applied specific criteria to identify those with confirmed clozapine-related, life-threatening agranulocytosis. In this study, we examine the cases not meeting these specific criteria. RESULTS: In the original study, 9 of 23 cases met the criteria for clozapine-induced, life-threatening agranulocytosis. Of the 13 remaining cases for whom data were available, 5 were probably caused by clozapine but were not life-threatening. Three cases were the result of concomitant cancer chemotherapy. Three were anomalous results probably related to measurement error. For the remaining two cases, the cause was not identified. CONCLUSION: Not all cases of agranulocytosis occurring in people taking clozapine are caused by clozapine. The widely used threshold criterion-based diagnosis overestimates the risk of agranulocytosis. True clozapine-related agranulocytosis is best identified by pattern-based criteria: rapid fall in neutrophil counts over around 2 weeks to below 0.5 × 109/L for two consecutive days (unless clozapine is stopped very early or granulocyte colony stimulating factor is given) where other possible causes (benign ethnic neutropenia, cancer chemotherapy) can be ruled out.

5.
Mol Metab ; 86: 101969, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38908793

RESUMO

OBJECTIVES: Cachexia is a metabolic disorder and comorbidity with cancer and heart failure. The syndrome impacts more than thirty million people worldwide, accounting for 20% of all cancer deaths. In acute myeloid leukemia, somatic mutations of the metabolic enzyme isocitrate dehydrogenase 1 and 2 cause the production of the oncometabolite D2-hydroxyglutarate (D2-HG). Increased production of D2-HG is associated with heart and skeletal muscle atrophy, but the mechanistic links between metabolic and proteomic remodeling remain poorly understood. Therefore, we assessed how oncometabolic stress by D2-HG activates autophagy and drives skeletal muscle loss. METHODS: We quantified genomic, metabolomic, and proteomic changes in cultured skeletal muscle cells and mouse models of IDH-mutant leukemia using RNA sequencing, mass spectrometry, and computational modeling. RESULTS: D2-HG impairs NADH redox homeostasis in myotubes. Increased NAD+ levels drive activation of nuclear deacetylase Sirt1, which causes deacetylation and activation of LC3, a key regulator of autophagy. Using LC3 mutants, we confirm that deacetylation of LC3 by Sirt1 shifts its distribution from the nucleus into the cytosol, where it can undergo lipidation at pre-autophagic membranes. Sirt1 silencing or p300 overexpression attenuated autophagy activation in myotubes. In vivo, we identified increased muscle atrophy and reduced grip strength in response to D2-HG in male vs. female mice. In male mice, glycolytic intermediates accumulated, and protein expression of oxidative phosphorylation machinery was reduced. In contrast, female animals upregulated the same proteins, attenuating the phenotype in vivo. Network modeling and machine learning algorithms allowed us to identify candidate proteins essential for regulating oncometabolic adaptation in mouse skeletal muscle. CONCLUSIONS: Our multi-omics approach exposes new metabolic vulnerabilities in response to D2-HG in skeletal muscle and provides a conceptual framework for identifying therapeutic targets in cachexia.


Assuntos
Autofagia , Glutaratos , Músculo Esquelético , Transdução de Sinais , Animais , Camundongos , Músculo Esquelético/metabolismo , Masculino , Glutaratos/metabolismo , Isocitrato Desidrogenase/metabolismo , Isocitrato Desidrogenase/genética , Caquexia/metabolismo , Feminino , Sirtuína 1/metabolismo , Sirtuína 1/genética , Camundongos Endogâmicos C57BL
6.
Can Med Educ J ; 15(2): 14-26, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38827914

RESUMO

Purpose: Competency-based medical education relies on feedback from workplace-based assessment (WBA) to direct learning. Unfortunately, WBAs often lack rich narrative feedback and show bias towards Medical Expert aspects of care. Building on research examining interactive assessment approaches, the Queen's University Internal Medicine residency program introduced a facilitated, team-based assessment initiative ("Feedback Fridays") in July 2017, aimed at improving holistic assessment of resident performance on the inpatient medicine teaching units. In this study, we aim to explore how Feedback Fridays contributed to formative assessment of Internal Medicine residents within our current model of competency-based training. Method: A total of 53 residents participated in facilitated, biweekly group assessment sessions during the 2017 and 2018 academic year. Each session was a 30-minute facilitated assessment discussion done with one inpatient team, which included medical students, residents, and their supervising attending. Feedback from the discussion was collected, summarized, and documented in narrative form in electronic WBA forms by the program's assessment officer for the residents. For research purposes, verbatim transcripts of feedback sessions were analyzed thematically. Results: The researchers identified four major themes for feedback: communication, intra- and inter-personal awareness, leadership and teamwork, and learning opportunities. Although feedback related to a broad range of activities, it showed strong emphasis on competencies within the intrinsic CanMEDS roles. Additionally, a clear formative focus in the feedback was another important finding. Conclusions: The introduction of facilitated team-based assessment in the Queen's Internal Medicine program filled an important gap in WBA by providing learners with detailed feedback across all CanMEDS roles and by providing constructive recommendations for identified areas for improvement.


Objectif: La formation médicale fondée sur les compétences s'appuie sur la rétroaction faite lors de l'évaluation des apprentissages par observation directe dans le milieu de travail. Malheureusement, les évaluations dans le milieu de travail omettent souvent de fournir une rétroaction narrative exhaustive et privilégient les aspects des soins relevant de l'expertise médicale. En se basant sur la recherche ayant étudié les approches d'évaluation interactive, le programme de résidence en médecine interne de l'Université Queen's a introduit en juillet 2017 une initiative d'évaluation facilitée et en équipe (« Les vendredis rétroaction ¼), visant à améliorer l'évaluation holistique du rendement des résidents dans les unités d'enseignement clinique en médecine interne. Dans cette étude, nous visons à explorer comment ces « vendredis rétroaction ¼ ont contribué à l'évaluation formative des résidents en médecine interne dans le cadre de notre modèle actuel de formation axée sur les compétences. Méthode: Au total, 53 résidents ont participé à des séances d'évaluation de groupe facilitées et bi-hebdomadaires au cours de l'année universitaire 2017-2018. Chaque séance consistait en une discussion d'évaluation facilitée de 30 minutes menée avec une équipe de l'unité de soins, qui comprenait des étudiants en médecine, des résidents et le médecin superviseur. Les commentaires issus de la discussion ont été recueillis, résumés et documentés sous forme narrative dans des formulaires électroniques d'observation directe dans le milieu de travail par le responsable de l'évaluation du programme de résidence. À des fins de recherche, les transcriptions verbatim des séances de rétroaction ont été analysées de façon thématique. Résultats: Les chercheurs ont identifié quatre thèmes principaux pour les commentaires : la communication, la conscience intra- et interpersonnelle, le leadership et le travail d'équipe, et les occasions d'apprentissage. Bien que la rétroaction concerne un large éventail d'activités, elle met fortement l'accent sur les compétences liées aux rôles intrinsèques de CanMEDS. De plus, le fait que la rétroaction avait un rôle clairement formatif est une autre constatation importante. Conclusions: L'introduction de l'évaluation en équipe facilitée dans le programme de médecine interne à Queen's a comblé une lacune importante dans l'apprentissage par observation directe dans le milieu de travail en fournissant aux apprenants une rétroaction détaillée sur tous les rôles CanMEDS et en formulant des recommandations constructives sur les domaines à améliorer.


Assuntos
Competência Clínica , Medicina Interna , Internato e Residência , Pesquisa Qualitativa , Medicina Interna/educação , Humanos , Educação Baseada em Competências/métodos , Feedback Formativo , Liderança , Retroalimentação , Avaliação Educacional/métodos , Comunicação
7.
Trauma Violence Abuse ; : 15248380241253041, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38828776

RESUMO

Young people who transition to adulthood from out-of-home care (OOHC) are more likely to experience a range of poorer outcomes relative to their same-age peers in the community. This systematic review assessed the effectiveness of policies or interventions (hereafter "interventions") aimed at improving housing, health, education, economic, and psychosocial outcomes for youth leaving OOHC (hereafter "care leavers"). Eleven databases of published literature were reviewed along with gray literature. Eligible studies used randomized or quasi-experimental designs and assessed interventions that provided support to care leavers prior to, during, or after they left OOHC. Primary outcomes were housing and homelessness, health and well-being, education, economic and employment, criminal and delinquent behavior, and risky behavior, while secondary outcomes were supportive relationships and life skills. Where possible, results were pooled in a meta-analysis. Certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation. Fourteen studies published in 27 reports were identified that examined independent living programs (ILPs) (n = 5), intensive support services (n = 2), coaching and peer support (C&PSP) (n = 2), transitional housing (n = 1), health information or coaching (n = 2), and extended care (n = 2). All but one study was conducted in the United States. Twenty small meta-analyses were undertaken encompassing ILPs and C&PSP, with two showing results that favored the intervention with certainty. The level of confidence in each meta-analysis was considered very low. A significant risk of bias was identified in each of the included studies. While some interventions showed promise, particularly extended care, the scope and strength of included evidence is insufficient to recommend any included approach.

8.
Ther Adv Psychopharmacol ; 14: 20451253241243297, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38827015

RESUMO

Tricyclic antidepressants (TCAs) remain widely prescribed for depression and many other conditions. There may be important differences between individual TCA in regard to their overdose toxicity and their cardiac toxicity in clinical use. We conducted a systematic review to compare the toxicity of individual TCA in overdose and the risk of serious adverse cardiac events occurring with therapeutic doses. We used the fatal toxicity index (FTI) and case fatality ratio as markers of fatality in overdose, and hazard ratios or odds ratios for the risk of cardiovascular adverse events during normal clinical use. In all, 30 reports of mortality in overdose and 14 observational studies assessing the risk of cardiovascular adverse events in clinical use were included. FTI values were of the same order of magnitude (101-102) for all TCAs except lofepramine. Desipramine appears to be somewhat more likely than other TCAs to lead to death in overdose. Amitriptyline, clomipramine, dothiepin/dosulepin, doxepin, trimipramine and imipramine showed broadly similar toxicity and were usually reported to be less toxic than desipramine. Data on nortriptyline were contradictory. Lofepramine had the lowest risk of death in overdose. The rank order of overdose toxicity was broadly consistent between different FTI definitions and between markers used. With respect to the risk of cardiovascular events at clinically relevant exposure, amitriptyline, nortriptyline and lofepramine were associated with a greater risk of in-use cardiotoxicity. All measures of overdose toxicity were subject to external influences and confounding. The continued use of TCAs in depression and other conditions should be minimized when considering their undoubted toxicity in overdose and possible toxicity in normal clinical use.


Older tricyclic antidepressants and their toxicity in overdose and in clinical use Tricyclic antidepressants were first used in the 1950s. Their use for depression has gone down in the past 20 or so years. This is because newer antidepressants are better tolerated and less toxic in overdose. Certain tricyclics - dosulepin and amitriptyline - have been identified as being particularly toxic tricyclics and their use has been restricted. However many other tricyclics remain widely used for depression and many other conditions. We examined all the evidence we could find on tricyclic toxicity. We found that, with one exception, all tricyclics are toxic and dangerous when taken in overdose. The exception is lofepramine - a tricyclic used in the UK and some other countries. When looking at toxicity in clinical use, we found no consistent evidence of difference between individual tricyclics. It is possible that most or all tricyclics do not increase the risk of heart attack or sudden cardiac death when used at normal clinical doses.

9.
Nature ; 630(8018): 961-967, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38740055

RESUMO

Although eukaryotic Argonautes have a pivotal role in post-transcriptional gene regulation through nucleic acid cleavage, some short prokaryotic Argonaute variants (pAgos) rely on auxiliary nuclease factors for efficient foreign DNA degradation1. Here we reveal the activation pathway of the DNA defence module DdmDE system, which rapidly eliminates small, multicopy plasmids from the Vibrio cholerae seventh pandemic strain (7PET)2. Through a combination of cryo-electron microscopy, biochemistry and in vivo plasmid clearance assays, we demonstrate that DdmE is a catalytically inactive, DNA-guided, DNA-targeting pAgo with a distinctive insertion domain. We observe that the helicase-nuclease DdmD transitions from an autoinhibited, dimeric complex to a monomeric state upon loading of single-stranded DNA targets. Furthermore, the complete structure of the DdmDE-guide-target handover complex provides a comprehensive view into how DNA recognition triggers processive plasmid destruction. Our work establishes a mechanistic foundation for how pAgos utilize ancillary factors to achieve plasmid clearance, and provides insights into anti-plasmid immunity in bacteria.


Assuntos
Proteínas Argonautas , Proteínas de Bactérias , Plasmídeos , Vibrio cholerae , Proteínas Argonautas/química , Proteínas Argonautas/metabolismo , Proteínas Argonautas/ultraestrutura , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/ultraestrutura , Microscopia Crioeletrônica , Desoxirribonucleases/química , Desoxirribonucleases/metabolismo , Desoxirribonucleases/ultraestrutura , DNA Helicases/química , DNA Helicases/metabolismo , DNA Helicases/ultraestrutura , DNA de Cadeia Simples/genética , DNA de Cadeia Simples/metabolismo , Modelos Moleculares , Plasmídeos/genética , Plasmídeos/imunologia , Plasmídeos/metabolismo , Domínios Proteicos , Multimerização Proteica , Vibrio cholerae/genética , Vibrio cholerae/imunologia , Vibrio cholerae/patogenicidade
10.
Med Teach ; : 1-9, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38818632

RESUMO

BACKGROUND: It is unclear whether alternating placements during clinical clerkship, without an explicit emphasis on clinical competencies, would bring about optimal educational outcomes. METHODS: This is an explanatory sequential mixed-methods research. We enrolled a convenience sample of 41 eight-year programme medical students in Sun Yat-sen University who received alternating placements during clerkship. The effects of competence-based approach (n = 21) versus traditional approach (n = 20) to clerkship teaching were compared. In the quantitative phase, course satisfaction was measured via an online survey and academic performance was determined through final scores on summative assessment. Then, in the qualitative phase, students were invited for semi-structured interviews about their learning experiences, and the transcripts were used for thematic analysis. RESULTS: Quantitative findings showed that students in the study group rated high course satisfaction and performed significantly better in their final scores compared with those in the control group. Qualitative findings from thematic analysis showed that students were relatively neutral about their preference on placement models, but clearly perceived, capitalised, and appreciated that their competencies were being cultivated by an instructor who was regarded as a positive role model. CONCLUSION: A competence-based approach to clerkship teaching resulted in better course satisfaction and academic performance, and was perceived, capitalised, and appreciated by students.

11.
J Affect Disord ; 358: 292-301, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38697222

RESUMO

BACKGROUND: Recent systematic reviews highlight great variability in defining and assessing treatment-resistant depression (TRD). A key problem is that definitions are consensus rather than data-led. This study seeks to offer a comprehensive socio-demographic and clinical description of a relevant sample. METHODS: As part of a pragmatic randomized controlled trial, patients (N = 129) were managed in primary care for persistent depression and diagnosed with TRD. Data included previous treatment attempts, characteristics of the depressive illness, functioning, quality of life, co-occurring problems including suicidality, psychiatric and personality disorders, physical health conditions, and adverse events. RESULTS: Findings show a severe and chronic course of depression with a duration of illness of 25+ years. Overall, 82.9 % had at least one other psychiatric diagnosis and 82.2 % at least one personality disorder; 69.8 % had significant musculoskeletal, gastrointestinal, genitourinary, or cardiovascular and respiratory physical health problems. All but 14 had severe difficulties in social and occupational functioning and reported severely impaired quality of life. Suicidal ideation was high: 44.9 % had made at least one serious suicide attempt and several reported multiple attempts with 17.8 % reporting a suicide attempt during childhood or adolescence. Of the patients, 79.8 % reported at least one adverse childhood experience. LIMITATIONS: Potential for recall bias, not examining possible interactions, and absence of a control group. CONCLUSIONS: Our findings reveal a complex and multifaceted condition and call for an urgent reconceptualization of TRD, which encompasses many interdependent variables and experiences. Individuals with TRD may be at a serious disadvantage in terms of receiving adequate treatment.


Assuntos
Transtorno Depressivo Resistente a Tratamento , Qualidade de Vida , Ideação Suicida , Tentativa de Suicídio , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Comorbidade , Transtorno Depressivo Resistente a Tratamento/terapia , Transtornos da Personalidade/terapia , Transtornos da Personalidade/epidemiologia , Tentativa de Suicídio/estatística & dados numéricos
13.
Pharmacol Ther ; 258: 108641, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38583670

RESUMO

Major depression is an established risk factor for subsequent dementia, and depression in late life may also represent a prodromal state of dementia. Considering current challenges in the clinical development of disease modifying therapies for dementia, the focus of research is shifting towards prevention and modification of risk factors to alter the neurodegenerative disease trajectory. Understanding mechanistic commonalities underlying affective symptoms and cognitive decline may reveal biomarkers to aid early identification of those at risk of progressing to dementia during the preclinical phase of disease, thus allowing for timely intervention. Adult hippocampal neurogenesis (AHN) is a phenomenon that describes the birth of new neurons in the dentate gyrus throughout life and it is associated with spatial learning, memory and mood regulation. Microglia are innate immune system macrophages in the central nervous system that carefully regulate AHN via multiple mechanisms. Disruption in AHN is associated with both dementia and major depression and microgliosis is a hallmark of several neurodegenerative diseases. Emerging evidence suggests that psychedelics promote neuroplasticity, including neurogenesis, and may also be immunomodulatory. In this context, psilocybin, a serotonergic agonist with rapid-acting antidepressant properties has the potential to ameliorate intersecting pathophysiological processes relevant for both major depression and neurodegenerative diseases. In this narrative review, we focus on the evidence base for the effects of psilocybin on adult hippocampal neurogenesis and microglial form and function; which may suggest that psilocybin has the potential to modulate multiple mechanisms of action, and may have implications in altering the progression from major depression to dementia in those at risk.


Assuntos
Demência , Transtorno Depressivo Maior , Doenças Neurodegenerativas , Neurogênese , Psilocibina , Humanos , Demência/prevenção & controle , Demência/tratamento farmacológico , Animais , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/prevenção & controle , Transtorno Depressivo Maior/tratamento farmacológico , Neurogênese/efeitos dos fármacos , Psilocibina/uso terapêutico , Psilocibina/farmacologia , Hipocampo/efeitos dos fármacos , Alucinógenos/farmacologia , Alucinógenos/uso terapêutico , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Microglia/efeitos dos fármacos
14.
Nat Commun ; 15(1): 3663, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38688943

RESUMO

CRISPR-Cas9 is a powerful tool for genome editing, but the strict requirement for an NGG protospacer-adjacent motif (PAM) sequence immediately next to the DNA target limits the number of editable genes. Recently developed Cas9 variants have been engineered with relaxed PAM requirements, including SpG-Cas9 (SpG) and the nearly PAM-less SpRY-Cas9 (SpRY). However, the molecular mechanisms of how SpRY recognizes all potential PAM sequences remains unclear. Here, we combine structural and biochemical approaches to determine how SpRY interrogates DNA and recognizes target sites. Divergent PAM sequences can be accommodated through conformational flexibility within the PAM-interacting region, which facilitates tight binding to off-target DNA sequences. Nuclease activation occurs ~1000-fold slower than for Streptococcus pyogenes Cas9, enabling us to directly visualize multiple on-pathway intermediate states. Experiments with SpG position it as an intermediate enzyme between Cas9 and SpRY. Our findings shed light on the molecular mechanisms of PAMless genome editing.


Assuntos
Proteína 9 Associada à CRISPR , Sistemas CRISPR-Cas , DNA , Edição de Genes , Streptococcus pyogenes , Proteína 9 Associada à CRISPR/metabolismo , Proteína 9 Associada à CRISPR/genética , Edição de Genes/métodos , DNA/metabolismo , DNA/genética , Streptococcus pyogenes/genética , Streptococcus pyogenes/metabolismo , Streptococcus pyogenes/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , RNA Guia de Sistemas CRISPR-Cas/metabolismo , RNA Guia de Sistemas CRISPR-Cas/genética
15.
Nat Commun ; 15(1): 3324, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38637512

RESUMO

CRISPR-Cas are adaptive immune systems in bacteria and archaea that utilize CRISPR RNA-guided surveillance complexes to target complementary RNA or DNA for destruction1-5. Target RNA cleavage at regular intervals is characteristic of type III effector complexes6-8. Here, we determine the structures of the Synechocystis type III-Dv complex, an apparent evolutionary intermediate from multi-protein to single-protein type III effectors9,10, in pre- and post-cleavage states. The structures show how multi-subunit fusion proteins in the effector are tethered together in an unusual arrangement to assemble into an active and programmable RNA endonuclease and how the effector utilizes a distinct mechanism for target RNA seeding from other type III effectors. Using structural, biochemical, and quantum/classical molecular dynamics simulation, we study the structure and dynamics of the three catalytic sites, where a 2'-OH of the ribose on the target RNA acts as a nucleophile for in line self-cleavage of the upstream scissile phosphate. Strikingly, the arrangement at the catalytic residues of most type III complexes resembles the active site of ribozymes, including the hammerhead, pistol, and Varkud satellite ribozymes. Our work provides detailed molecular insight into the mechanisms of RNA targeting and cleavage by an important intermediate in the evolution of type III effector complexes.


Assuntos
Proteínas Associadas a CRISPR , RNA Catalítico , RNA/metabolismo , RNA Catalítico/metabolismo , Sistemas CRISPR-Cas/genética , DNA/metabolismo , Domínio Catalítico , Proteínas Associadas a CRISPR/genética , Proteínas Associadas a CRISPR/metabolismo , Clivagem do RNA
16.
Biophys J ; 123(11): 1494-1507, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38462838

RESUMO

Membrane-associated protein phase separation plays critical roles in cell biology, driving essential cellular phenomena from immune signaling to membrane traffic. Importantly, by reducing dimensionality from three to two dimensions, lipid bilayers can nucleate phase separation at far lower concentrations compared with those required for phase separation in solution. How might other intracellular lipid substrates, such as lipid droplets, contribute to nucleation of phase separation? Distinct from bilayer membranes, lipid droplets consist of a phospholipid monolayer surrounding a core of neutral lipids, and they are energy storage organelles that protect cells from lipotoxicity and oxidative stress. Here, we show that intrinsically disordered proteins can undergo phase separation on the surface of synthetic and cell-derived lipid droplets. Specifically, we find that the model disordered domains FUS LC and LAF-1 RGG separate into protein-rich and protein-depleted phases on the surfaces of lipid droplets. Owing to the hydrophobic nature of interactions between FUS LC proteins, increasing ionic strength drives an increase in its phase separation on droplet surfaces. The opposite is true for LAF-1 RGG, owing to the electrostatic nature of its interprotein interactions. In both cases, protein-rich phases on the surfaces of synthetic and cell-derived lipid droplets demonstrate molecular mobility indicative of a liquid-like state. Our results show that lipid droplets can nucleate protein condensates, suggesting that protein phase separation could be key in organizing biological processes involving lipid droplets.


Assuntos
Gotículas Lipídicas , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/metabolismo , Humanos , Proteína FUS de Ligação a RNA/química , Proteína FUS de Ligação a RNA/metabolismo , Transição de Fase , Interações Hidrofóbicas e Hidrofílicas , Domínios Proteicos , Separação de Fases
17.
Artigo em Inglês | MEDLINE | ID: mdl-38519870

RESUMO

OBJECTIVE: There are compelling ethical and practical reasons for patient engagement in research (PEIR), however, evidence for best practices remains limited. We investigated PEIR as implemented in CAPTURE ALS, a longitudinal observational study, from study inception through the first 2.5 years of operations. METHODS: Data were drawn from three engagement initiatives: a community-led letter-writing campaign; consultation with patient and caregiver focus groups; and a study-embedded 'participant partner advisory council' (PPAC). Data were derived retrospectively from study documentation. We used the International Association of Public Participation (IAP2) participation spectrum as a framework for investigation. RESULTS: 2401 letters from community members to the Canadian government affirmed study objectives and advocated for funding. Feedback from focus group consultation influenced study design and supported the study's data-sharing plan. PPAC collaboration shaped all aspects of the study. Contributions included: co-creation of governance documents, input on study protocols and public-facing communication, and development of engagement webinars for study participants and feedback surveys. Effective communication practices fostered collaboration and helped avoid tokenistic engagement. CAPTURE ALS encompassed all IAP2 participation levels. CONCLUSIONS: CAPTURE ALS was shaped by meaningful engagement initiatives over the course of the study. Lessons learned included: begin early and embed PEIR within research; build relationships and foster mutual learning; be flexible, open to adaptation, and seek diversity. Primary challenges included funding for early implementation, time needed to maintain relationships, and attrition due to disease progression. All IAP2 participation levels contributed to meaningful PEIR. 'Empowerment' was demonstrated through advocacy.


Assuntos
Esclerose Lateral Amiotrófica , Participação do Paciente , Humanos , Esclerose Lateral Amiotrófica/psicologia , Estudos Longitudinais , Participação do Paciente/psicologia , Participação do Paciente/estatística & dados numéricos , Canadá/epidemiologia , Masculino , Pesquisa Biomédica , Feminino
18.
J Proteome Res ; 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38533909

RESUMO

Quantitation of proteins using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is complex, with a multiplicity of options ranging from label-free techniques to chemically and metabolically labeling proteins. Increasingly, for clinically relevant analyses, stable isotope-labeled (SIL) internal standards (ISs) represent the "gold standard" for quantitation due to their similar physiochemical properties to the analyte, wide availability, and ability to multiplex to several peptides. However, the purchase of SIL-ISs is a resource-intensive step in terms of cost and time, particularly for screening putative biomarker panels of hundreds of proteins. We demonstrate an alternative strategy utilizing nonhuman sera as the IS for quantitation of multiple human proteins. We demonstrate the effectiveness of this strategy using two high abundance clinically relevant analytes, vitamin D binding protein [Gc globulin] (DBP) and albumin (ALB). We extend this to three putative risk markers for cardiovascular disease: plasma protease C1 inhibitor (SERPING1), annexin A1 (ANXA1), and protein kinase, DNA-activated catalytic subunit (PRKDC). The results show highly specific, reproducible, and linear measurement of the proteins of interest with comparable precision and accuracy to the gold standard SIL-IS technique. This approach may not be applicable to every protein, but for many proteins it can offer a cost-effective solution to LC-MS/MS protein quantitation.

19.
Eur Psychiatry ; 67(1): e15, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38450540

RESUMO

BACKGROUND: Paliperidone palmitate 3-monthly (PP3M) has been tested in 1-year controlled studies. The aim of this study was to examine the relapse outcomes with PP3M monotherapy at 3 years in patients with schizophrenia. METHODS: This was an observational, non-interventional study of patients started on PP3M according to their clinical need. All patients had a diagnosis of schizophrenia (ICD-10 F20) and were between 18 and 65 years of age. The study took place in a mental health facility in South East London, UK. RESULTS: Among the 166 patients who started PP3M, 97 (58%) met inclusion criteria and were observed for 36 months. In total, five patients (5%) experienced a relapse (defined as step-up in clinical care) while on PP3M. There were no relapses between months 18 and 36. Of the original 97 patients, 56 (58%) remained on PP3M monotherapy at 3 years, and 71 (73%) remained on either PP3M or paliperidone palmitate one-monthly. Reasons for discontinuation of PP3M included patient refusal (n = 11, 33% of discontinuations) and adverse effects in (n = 8, 24%). CONCLUSION: PP3M is a highly effective monotherapy treatment for reducing relapse in people with schizophrenia.


Assuntos
Palmitato de Paliperidona , Esquizofrenia , Humanos , Palmitato de Paliperidona/efeitos adversos , Esquizofrenia/tratamento farmacológico , Seguimentos , Hospitais Psiquiátricos , Recidiva
20.
J Am Med Inform Assoc ; 31(5): 1144-1150, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38447593

RESUMO

OBJECTIVE: To evaluate the real-world performance of the SMART/HL7 Bulk Fast Health Interoperability Resources (FHIR) Access Application Programming Interface (API), developed to enable push button access to electronic health record data on large populations, and required under the 21st Century Cures Act Rule. MATERIALS AND METHODS: We used an open-source Bulk FHIR Testing Suite at 5 healthcare sites from April to September 2023, including 4 hospitals using electronic health records (EHRs) certified for interoperability, and 1 Health Information Exchange (HIE) using a custom, standards-compliant API build. We measured export speeds, data sizes, and completeness across 6 types of FHIR. RESULTS: Among the certified platforms, Oracle Cerner led in speed, managing 5-16 million resources at over 8000 resources/min. Three Epic sites exported a FHIR data subset, achieving 1-12 million resources at 1555-2500 resources/min. Notably, the HIE's custom API outperformed, generating over 141 million resources at 12 000 resources/min. DISCUSSION: The HIE's custom API showcased superior performance, endorsing the effectiveness of SMART/HL7 Bulk FHIR in enabling large-scale data exchange while underlining the need for optimization in existing EHR platforms. Agility and scalability are essential for diverse health, research, and public health use cases. CONCLUSION: To fully realize the interoperability goals of the 21st Century Cures Act, addressing the performance limitations of Bulk FHIR API is critical. It would be beneficial to include performance metrics in both certification and reporting processes.


Assuntos
Troca de Informação em Saúde , Nível Sete de Saúde , Software , Registros Eletrônicos de Saúde , Atenção à Saúde
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