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The exponential rise of information available means we can now, in theory, access knowledge on almost any question we ask. However, as the amount of unverified information increases, so too does the challenge in deciding which information to trust. Farmers, when learning about agricultural innovations, have historically relied on in-person advice from traditional 'experts', such as agricultural advisers, to inform farm management. As more farmers go online for information, it is not clear whether they are now using digital information to corroborate in-person advice from traditional 'experts', or if they are foregoing 'expert' advice in preference for peer-generated information. To fill this knowledge gap, we sought to understand how farmers in two contrasting European countries (Hungary and the UK) learnt about sustainable soil innovations and who influenced them to innovate. Through interviews with 82 respondents, we found farmers in both countries regularly used online sources to access soil information; some were prompted to change their soil management by farmer social media 'influencers'. However, online information and interactions were not usually the main factor influencing farmers to change their practices. Farmers placed most trust in other farmers to learn about new soil practices and were less trusting of traditional 'experts', particularly agricultural researchers from academic and government institutions, who they believed were not empathetic towards farmers' needs. We suggest that some farmers may indeed have had enough of traditional 'experts', instead relying more on their own peer networks to learn and innovate. We discuss ways to improve trustworthy knowledge exchange between agricultural stakeholders to increase uptake of sustainable soil management practices, while acknowledging the value of peer influence and online interactions for innovation and trust building.
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Agricultura , Agricultores , Europa (Continente) , Granjas , Humanos , SueloRESUMEN
BACKGROUND: Acute childhood strabismus is often a clinical conundrum faced by ophthalmologists. Currently, there are no clear clinical guidelines on how to investigate a child presenting with acute strabismus. Furthermore, there is no consensus as to whether to initially perform neuroimaging of a child to rule out the small but serious risk of intracranial pathology, or to pursue a careful observational approach. This paper aims to outline a standardised approach to investigating acute strabismus in paediatric patients. METHODS: A retrospective chart review of all paediatric patients that presented over a 10-year period to the ophthalmology departments at two tertiary level hospitals in New Zealand was conducted. Patients under 18 years of age with an acute presentation of strabismus, who underwent neuroimaging, were included. RESULTS: A total of 500 patient records were reviewed. Seventy patients met the study inclusion criteria. Of these patients, 17 (24.3%) had non-isolated strabismus while 53 patients (75.7%) had isolated strabismus. Twelve patients (70.6%) who presented with a non-isolated strabismus had abnormal neuroimaging. Of those who presented with an isolated strabismus, 4 (7.5%) had abnormal neuroimaging. CONCLUSIONS: Acute onset non-isolated strabismus is a significant predictor of underlying neurological abnormality in children and requires urgent neuroimaging. However, a cautious approach in which there is close observation, along with general paediatric and/or paediatric neurology input, may be appropriate for children presenting acutely with an isolated strabismus.
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Estrabismo , Adolescente , Niño , Humanos , Neuroimagen , Nueva Zelanda , Estudios Retrospectivos , Estrabismo/diagnósticoRESUMEN
Immunological memory is a defining feature of vertebrate physiology, allowing rapid responses to repeat infections. However, the molecular mechanisms required for its establishment and maintenance remain poorly understood. Here, we demonstrated that the first steps in the acquisition of T-cell memory occurred during the initial activation phase of naïve T cells by an antigenic stimulus. This event initiated extensive chromatin remodeling that reprogrammed immune response genes toward a stably maintained primed state, prior to terminal differentiation. Activation induced the transcription factors NFAT and AP-1 which created thousands of new DNase I-hypersensitive sites (DHSs), enabling ETS-1 and RUNX1 recruitment to previously inaccessible sites. Significantly, these DHSs remained stable long after activation ceased, were preserved following replication, and were maintained in memory-phenotype cells. We show that primed DHSs maintain regions of active chromatin in the vicinity of inducible genes and enhancers that regulate immune responses. We suggest that this priming mechanism may contribute to immunological memory in T cells by facilitating the induction of nearby inducible regulatory elements in previously activated T cells.
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Cromatina/metabolismo , Memoria Inmunológica , Linfocitos T/metabolismo , Animales , Células Cultivadas , Quimiocina CCL1/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Desoxirribonucleasa I/metabolismo , Expresión Génica , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Humanos , Interleucina-3/genética , Células Jurkat , Ratones Transgénicos , Factores de Transcripción NFATC/genética , Proteína Proto-Oncogénica c-ets-1/genética , ARN Mensajero/metabolismo , Bazo/inmunología , Linfocitos T/inmunología , Factor de Transcripción AP-1/genéticaRESUMEN
While excessive production of reactive oxygen species (ROS) is a characteristic hallmark of numerous diseases, clinical approaches that ameliorate oxidative stress have been unsuccessful. Here, utilizing multi-omics, we demonstrate that in cardiomyocytes, mitochondrial isocitrate dehydrogenase (IDH2) constitutes a major antioxidative defense mechanism. Paradoxically reduced expression of IDH2 associated with ventricular eccentric hypertrophy is counterbalanced by an increase in the enzyme activity. We unveil redox-dependent sex dimorphism, and extensive mutual regulation of the antioxidative activities of IDH2 and NRF2 by a feedforward network that involves 2-oxoglutarate and L-2-hydroxyglutarate and mediated in part through unconventional hydroxy-methylation of cytosine residues present in introns. Consequently, conditional targeting of ROS in a murine model of heart failure improves cardiac function in sex- and phenotype-dependent manners. Together, these insights may explain why previous attempts to treat heart failure with antioxidants have been unsuccessful and open new approaches to personalizing and, thereby, improving such treatment.
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Insuficiencia Cardíaca , Estrés Oxidativo , Ratones , Animales , Especies Reactivas de Oxígeno/metabolismo , Antioxidantes/metabolismo , Oxidación-Reducción , Insuficiencia Cardíaca/genética , Cardiomegalia , Epigénesis Genética , Isocitrato Deshidrogenasa/genéticaRESUMEN
Hyperpolarizing GABAAR currents, the unitary events that underlie synaptic inhibition, are dependent upon efficient Cl- extrusion, a process that is facilitated by the neuronal specific K+/Cl- co-transporter KCC2. Its activity is also a determinant of the anticonvulsant efficacy of the canonical GABAAR-positive allosteric: benzodiazepines (BDZs). Compromised KCC2 activity is implicated in the pathophysiology of status epilepticus (SE), a medical emergency that rapidly becomes refractory to BDZ (BDZ-RSE). Here, we have identified small molecules that directly bind to and activate KCC2, which leads to reduced neuronal Cl- accumulation and excitability. KCC2 activation does not induce any overt effects on behavior but prevents the development of and terminates ongoing BDZ-RSE. In addition, KCC2 activation reduces neuronal cell death following BDZ-RSE. Collectively, these findings demonstrate that KCC2 activation is a promising strategy to terminate BDZ-resistant seizures and limit the associated neuronal injury.
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Estado Epiléptico , Simportadores , Ratones , Animales , Benzodiazepinas/farmacología , Benzodiazepinas/uso terapéutico , Estado Epiléptico/tratamiento farmacológico , Convulsiones/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Simportadores/metabolismoRESUMEN
Enhancing the removal of aggregate-prone toxic proteins is a rational therapeutic strategy for a number of neurodegenerative diseases, especially Huntington's disease and various spinocerebellar ataxias. Ideally, such approaches should preferentially clear the mutant/misfolded species, while having minimal impact on the stability of wild-type/normally-folded proteins. Furthermore, activation of both ubiquitin-proteasome and autophagy-lysosome routes may be advantageous, as this would allow effective clearance of both monomeric and oligomeric species, the latter which are inaccessible to the proteasome. Here we find that compounds that activate the D1 ATPase activity of VCP/p97 fulfill these requirements. Such effects are seen with small molecule VCP activators like SMER28, which activate autophagosome biogenesis by enhancing interactions of PI3K complex components to increase PI(3)P production, and also accelerate VCP-dependent proteasomal clearance of such substrates. Thus, this mode of VCP activation may be a very attractive target for many neurodegenerative diseases.
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Adenosina Trifosfatasas , Enfermedades Neurodegenerativas , Proteína que Contiene Valosina , Adenosina Trifosfatasas/metabolismo , Autofagia , Proteínas de Ciclo Celular/metabolismo , Humanos , Enfermedades Neurodegenerativas/genética , Fosfatos de Fosfatidilinositol , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteína que Contiene Valosina/genética , Proteína que Contiene Valosina/metabolismoRESUMEN
OBJECTIVES: To better understand the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among healthcare workers, leading to recommendations for the prioritisation of personal protective equipment, testing, training and vaccination. DESIGN: Observational, longitudinal, national cohort study. SETTING: Our cohort were secondary care (hospital-based) healthcare workers employed by NHS Wales (United Kingdom) organisations from 1 April 2020 to 30 November 2020. PARTICIPANTS: We included 577,756 monthly observations among 77,587 healthcare workers. Using linked anonymised datasets, participants were grouped into 20 staff roles. Additionally, each role was deemed either patient-facing, non-patient-facing or undetermined. This was linked to individual demographic details and dates of positive SARS-CoV-2 PCR tests. MAIN OUTCOME MEASURES: We used univariable and multivariable logistic regression models to determine odds ratios (ORs) for the risk of a positive SARS-CoV-2 PCR test. RESULTS: Patient-facing healthcare workers were at the highest risk of SARS-CoV-2 infection with an adjusted OR (95% confidence interval [CI]) of 2.28 (95% CI 2.10-2.47). We found that after adjustment, foundation year doctors (OR 1.83 [95% CI 1.47-2.27]), healthcare support workers [OR 1.36 [95% CI 1.20-1.54]) and hospital nurses (OR 1.27 [95% CI 1.12-1.44]) were at the highest risk of infection among all staff groups. Younger healthcare workers and those living in more deprived areas were at a higher risk of infection. We also observed that infection rates varied over time and by organisation. CONCLUSIONS: These findings have important policy implications for the prioritisation of vaccination, testing, training and personal protective equipment provision for patient-facing roles and the higher risk staff groups.
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COVID-19 , Humanos , Estudios de Cohortes , Estudios Longitudinales , COVID-19/epidemiología , SARS-CoV-2 , Reino Unido/epidemiología , Personal de SaludRESUMEN
Huntington's disease (HD) is a lethal autosomal dominant neurodegenerative disorder resulting from a CAG repeat expansion in the huntingtin (HTT) gene. The product of translation of this gene is a highly aggregation-prone protein containing a polyglutamine tract >35 repeats (mHTT) that has been shown to colocalize with histone deacetylase 4 (HDAC4) in cytoplasmic inclusions in HD mouse models. Genetic reduction of HDAC4 in an HD mouse model resulted in delayed aggregation of mHTT, along with amelioration of neurological phenotypes and extended lifespan. To further investigate the role of HDAC4 in cellular models of HD, we have developed bifunctional degraders of the protein and report the first potent and selective degraders of HDAC4 that show an effect in multiple cell lines, including HD mouse model-derived cortical neurons. These degraders act via the ubiquitin-proteasomal pathway and selectively degrade HDAC4 over other class IIa HDAC isoforms (HDAC5, HDAC7, and HDAC9).
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Histona Desacetilasas , Enfermedad de Huntington , Animales , Modelos Animales de Enfermedad , Desarrollo de Medicamentos , Histona Desacetilasas/metabolismo , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Enfermedad de Huntington/genética , Ratones , Neuronas/metabolismo , Proteolisis , UbiquitinasRESUMEN
Using an iterative structure-activity relationship driven approach, we identified a CNS-penetrant 5-(trifluoromethyl)-1,2,4-oxadiazole (TFMO, 12) with a pharmacokinetic profile suitable for probing class IIa histone deacetylase (HDAC) inhibition in vivo. Given the lack of understanding of endogenous class IIa HDAC substrates, we developed a surrogate readout to measure compound effects in vivo, by exploiting the >100-fold selectivity compound 12 exhibits over class I/IIb HDACs. We achieved adequate brain exposure with compound 12 in mice to estimate a class I/IIb deacetylation EC50, using class I substrate H4K12 acetylation and global acetylation levels as a pharmacodynamic readout. We observed excellent correlation between the compound 12 in vivo pharmacodynamic response and in vitro class I/IIb cellular activity. Applying the same relationship to class IIa HDAC inhibition, we estimated the compound 12 dose required to inhibit class IIa HDAC activity, for use in preclinical models of Huntington's disease.
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BACKGROUND: Early Intervention in Psychosis (EIP) services improve health outcomes for young people with psychosis in the medium-long term, but 25% of young people disengage in the first 12 months with costs to their mental health, families, society and the NHS. This study will evaluate the effectiveness, cost-effectiveness and implementation of a team-based motivational Early Youth Engagement (EYE-2) intervention. METHOD: The study design is a cluster randomised controlled trial (RCT) with economic evaluation, comparing the EYE-2 intervention + standardised EIP service to standardised EIP service alone, with randomisation at the team level. A process evaluation will evaluate the delivery of the intervention qualitatively and quantitatively across contexts. The setting is 20 EIP teams in 5 sites: Manchester, South London, East Anglia, Thames Valley and Hampshire. Participants are young people (14-35 years) with first episode psychosis, and EIP staff. The intervention is the team-based motivational engagement (EYE-2) intervention, delivered alongside standardised EIP services, and supported by additional training, website, booklets and social groups. The comparator is the standardised EIP service. Both interventions are delivered by EIP clinicians. The primary outcome is time to disengagement (time in days from date of allocation to care coordinator to date of last contact following refusal to engage with EIP service, or lack of response to EIP contact for a consecutive 3-month period). Secondary outcomes include mental and physical health, deaths, social and occupational function, recovery, satisfaction and service use at 6, 12, 18 and 24 months. A 12-month within-trial economic evaluation will investigate cost-effectiveness from a societal perspective and from an NHS perspective. DISCUSSION: The trial will provide the first test of an engagement intervention in standardised care, with the potential for significant impact on the mental health and wellbeing of young people and their families, and economic benefits for services. The intervention will be highly scalable, supported by the toolkit including manuals, commissioning guide, training and resources, adapted to meet the needs of the diverse EIP population, and based on an in-depth process evaluation. TRIAL REGISTRATION: ISRCTN 51629746 prospectively registered 7th May 2019. Date assigned 10th May 2019.
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Trastornos Psicóticos , Adolescente , Análisis Costo-Beneficio , Humanos , Londres , Salud Mental , Motivación , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/terapiaRESUMEN
Societal biosecurity - measures built into everyday society to minimize risks from pests and diseases - is an important aspect of managing epidemics and pandemics. We aimed to identify societal options for reducing the transmission and spread of respiratory viruses. We used SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) as a case study to meet the immediate need to manage the COVID-19 pandemic and eventually transition to more normal societal conditions, and to catalog options for managing similar pandemics in the future. We used a 'solution scanning' approach. We read the literature; consulted psychology, public health, medical, and solution scanning experts; crowd-sourced options using social media; and collated comments on a preprint. Here, we present a list of 519 possible measures to reduce SARS-CoV-2 transmission and spread. We provide a long list of options for policymakers and businesses to consider when designing biosecurity plans to combat SARS-CoV-2 and similar pathogens in the future. We also developed an online application to help with this process. We encourage testing of actions, documentation of outcomes, revisions to the current list, and the addition of further options.
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Our group has recently shown that brain-penetrant ataxia telangiectasia-mutated (ATM) kinase inhibitors may have potential as novel therapeutics for the treatment of Huntington's disease (HD). However, the previously described pyranone-thioxanthenes (e.g., 4) failed to afford selectivity over a vacuolar protein sorting 34 (Vps34) kinase, an important kinase involved with autophagy. Given that impaired autophagy has been proposed as a pathogenic mechanism of neurodegenerative diseases such as HD, achieving selectivity over Vps34 became an important objective for our program. Here, we report the successful selectivity optimization of ATM over Vps34 by using X-ray crystal structures of a Vps34-ATM protein chimera where the Vps34 ATP-binding site was mutated to approximate that of an ATM kinase. The morpholino-pyridone and morpholino-pyrimidinone series that resulted as a consequence of this selectivity optimization process have high ATM potency and good oral bioavailability and have lower molecular weight, reduced lipophilicity, higher aqueous solubility, and greater synthetic tractability compared to the pyranone-thioxanthenes.
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Proteínas de la Ataxia Telangiectasia Mutada/antagonistas & inhibidores , Piridonas/química , Pirimidinonas/química , Animales , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Sitios de Unión , Encéfalo/metabolismo , Fosfatidilinositol 3-Quinasas Clase III/antagonistas & inhibidores , Fosfatidilinositol 3-Quinasas Clase III/metabolismo , Cristalografía por Rayos X , Diseño de Fármacos , Semivida , Humanos , Enfermedad de Huntington/tratamiento farmacológico , Masculino , Ratones , Ratones Endogámicos C57BL , Simulación de Dinámica Molecular , Morfolinos/química , Piridonas/metabolismo , Piridonas/uso terapéutico , Pirimidinonas/metabolismo , Pirimidinonas/uso terapéutico , Relación Estructura-ActividadRESUMEN
During exploration for oil and gas, a technical drilling fluid is used to lubricate the drill bit, maintain hydrostatic pressure, transmit sensor readings, remove rock cuttings and inhibit swelling of unstable clay based reactive shale formations. Increasing environmental awareness and resulting legislation has led to the search for new, improved biodegradable drilling fluid components. In the case of additives for clay swelling inhibition, an understanding of how existing effective additives interact with clays must be gained to allow the design of improved molecules. Owing to the disordered nature and nanoscopic dimension of the interlayer pores of clay minerals, computer simulations have become an increasingly useful tool for studying clay-swelling inhibitor interactions. In this work we briefly review the history of the development of technical drilling fluids, the environmental impact of drilling fluids and the use of computer simulations to study the interactions between clay minerals and swelling inhibitors. We report on results from some recent large-scale molecular dynamics simulation studies on low molecular weight water-soluble macromolecular inhibitor molecules. The structure and interactions of poly(propylene oxide)-diamine, poly(ethylene glycol) and poly(ethylene oxide)-diacrylate inhibitor molecules with montmorillonite clay are studied.
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Genetic and pharmacological evidence indicates that the reduction of ataxia telangiectasia-mutated (ATM) kinase activity can ameliorate mutant huntingtin (mHTT) toxicity in cellular and animal models of Huntington's disease (HD), suggesting that selective inhibition of ATM could provide a novel clinical intervention to treat HD. Here, we describe the development and characterization of ATM inhibitor molecules to enable in vivo proof-of-concept studies in HD animal models. Starting from previously reported ATM inhibitors, we aimed with few modifications to increase brain exposure by decreasing P-glycoprotein liability while maintaining potency and selectivity. Here, we report brain-penetrant ATM inhibitors that have robust pharmacodynamic (PD) effects consistent with ATM kinase inhibition in the mouse brain and an understandable pharmacokinetic/PD (PK/PD) relationship. Compound 17 engages ATM kinase and shows robust dose-dependent inhibition of X-ray irradiation-induced KAP1 phosphorylation in the mouse brain. Furthermore, compound 17 protects against mHTT (Q73)-induced cytotoxicity in a cortical-striatal cell model of HD.
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Proteínas de la Ataxia Telangiectasia Mutada/antagonistas & inhibidores , Enfermedad de Huntington/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Modelos Animales de Enfermedad , Perros , Humanos , Células de Riñón Canino Madin Darby , Ratones , Fármacos Neuroprotectores/metabolismo , Fármacos Neuroprotectores/farmacocinética , Prueba de Estudio ConceptualRESUMEN
The ability of poly(anhydride-esters) composed of non-steroidal anti-inflammatory drugs that biodegrade to salicylic acid (SA) and adipic acid to prevent colonization by Pseudomonas aeruginosa and their effects on the foreign-body response were studied in vitro and in vivo, respectively. Soluble SA in bacterial medium at concentrations up to 300 mg/L did not affect the growth rate or viability of P. aeruginosa, indicating that SA does not exhibit a direct toxicity effect on the bacterium. Batch degradation rates of the salicylate-based polymer in the presence of an actively growing bacterial culture only marginally (14%) increased relative to polymer degradation rates in sterile medium. Short-term (3h) bacterial adhesion studies in agitated batch systems indicated a 47% reduction in the rate of P. aeruginosa adhesion relative to a control polymer that does not release SA upon biodegradation. Long-term (3-day) biofilm accumulation studies indicated a dramatic reduction in biofilm formation on salicylate-based polymer versus controls. A recombinant P. aeruginosa pMHLAS, containing a fluorescent reporter gene prior to the las regulon, was employed to determine whether salicylate-based polymer prevents biofilm formation by the released SA inhibiting quorum sensing pathways. Long-term biofilm accumulation studies with P. aeruginosa pMHLAS insinuate that salicylate-based polymer prevents biofilm accumulation by inhibiting the las quorum sensing system. Furthermore, unlike control polymer, salicylate-based polymer implanted subcutaneously for a period of 4 weeks-resisted cell-mediated degradation and remained intact. Histological and immunohistochemical analysis indicated a reduction in overall encapsulation and paucity of macrophages in the area of the salicylate-based polymer implant.
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Antiinflamatorios no Esteroideos/farmacología , Biopelículas/efectos de los fármacos , Cuerpos Extraños/inmunología , Sistema Inmunológico/efectos de los fármacos , Polianhídridos/metabolismo , Pseudomonas aeruginosa/efectos de los fármacos , Antiinfecciosos/farmacología , Materiales Biocompatibles/metabolismo , Ácido Salicílico/farmacologíaRESUMEN
Potent and selective class IIa HDAC tetrasubstituted cyclopropane hydroxamic acid inhibitors were identified with high oral bioavailability that exhibited good brain and muscle exposure. Compound 14 displayed suitable properties for assessment of the impact of class IIa HDAC catalytic site inhibition in preclinical disease models.
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Synthesis of (S)-2-methyl-3-fluorophenyl cyclopentanone methyl ester (1S)-1 has been achieved by both inter- and intramolecular alkylation reactions on multigram scale, using chiral pool reagents. The intramolecular variant is a novel example of a chiral bis-electrophile reacting with a carbon nucleophile to form an enantiomerically pure all-carbon quaternary center.
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Inhibition of class IIa histone deacetylase (HDAC) enzymes have been suggested as a therapeutic strategy for a number of diseases, including Huntington's disease. Catalytic-site small molecule inhibitors of the class IIa HDAC4, -5, -7, and -9 were developed. These trisubstituted diarylcyclopropanehydroxamic acids were designed to exploit a lower pocket that is characteristic for the class IIa HDACs, not present in other HDAC classes. Selected inhibitors were cocrystallized with the catalytic domain of human HDAC4. We describe the first HDAC4 catalytic domain crystal structure in a "closed-loop" form, which in our view represents the biologically relevant conformation. We have demonstrated that these molecules can differentiate class IIa HDACs from class I and class IIb subtypes. They exhibited pharmacokinetic properties that should enable the assessment of their therapeutic benefit in both peripheral and CNS disorders. These selective inhibitors provide a means for evaluating potential efficacy in preclinical models in vivo.
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Diseño de Fármacos , Inhibidores de Histona Desacetilasas/farmacología , Histona Desacetilasas/metabolismo , Enfermedad de Huntington/tratamiento farmacológico , Animales , Relación Dosis-Respuesta a Droga , Inhibidores de Histona Desacetilasas/síntesis química , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/farmacocinética , Histona Desacetilasas/clasificación , Humanos , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Microsomas Hepáticos/química , Microsomas Hepáticos/metabolismo , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
During exploration for oil and gas, a technical drilling fluid is used to lubricate the drill bit, maintain hydrostatic pressure, transmit sensor readings, remove rock cuttings and inhibit swelling of unstable clay based reactive shale formations. Increasing environmental awareness and resulting legislation has led to the search for new, improved biodegradable drilling fluid components. In the case of additives for clay swelling inhibition, an understanding of how existing effective additives interact with clays must be gained to allow the design of improved molecules. Owing to the disordered nature and nanoscopic dimension of the interlayer pores of clay minerals, computer simulations have become an increasingly useful tool for studying clay-swelling inhibitor interactions. In this work we briefly review the history of the development of technical drilling fluids, the environmental impact of drilling fluids and the use of computer simulations to study the interactions between clay minerals and swelling inhibitors. We report on results from some recent large-scale molecular dynamics simulation studies on low molecular weight water-soluble macromolecular inhibitor molecules. The structure and interactions of poly(propylene oxide)-diamine, poly(ethylene glycol) and poly(ethylene oxide)-diacrylate inhibitor molecules with montmorillonite clay are studied.
Durante a exploração de óleo e gás um fluido de perfuração é usado para lubrificar 'bit' da perfuradora, manter a pressão hidrostática, transmitir sensores de leitura, remover resíduos da rocha e inibir o inchamento da argila instável baseada nas formações dos folhelhos. O aumento das preocupações ambientais bem como a legislação resultante levou à procura de novos fluidos de perfuração com componentes biodegradáveis. No caso dos aditivos para inibir o inchamento das argilas o entendimento das interações entre os aditivos e as argilas tem que ser adquirido para permitir o projeto de moléculas commelhores propriedades. Devido à natureza desordenada da dimensão nanoscópica dos nano poros dos minerais argilosos, simulações computacionais têm se tornado uma ferramenta poderosa para estudar as interações entre o inchamento da argila e o inibidor. Neste trabalho revisamos brevemente o histórico do desenvolvimento de fluidos técnicos de perfuração, o impacto ambiental dos fluidos de perfuração e o uso de simulações computacionais para estudar as interações entre os fluidos de perfuração e os inibidores do inchamento. Nós reportamos resultados para alguns estudos baseados em simulações de dinâmica molecular em larga escala em uma solução aquosa de baixo peso molecular com solutos compostos por macromoléculas inibidoras. A estrutura e as interações entre inibidores compostos por polipropileno óxido, polietileno óxido e moléculas e a argila montmorilonita são estudadas.