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1.
Methods Mol Biol ; 2805: 89-100, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39008175

RESUMEN

Engineered heart tissues (EHTs) have been shown to be a valuable platform for disease investigation and therapeutic testing by increasing human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) maturity and better recreating the native cardiac environment. The protocol detailed in this chapter describes the generation of miniaturized EHTs (mEHTs) incorporating hiPSC-CMs and human stromal cells in a fibrin hydrogel. This platform utilizes an array of silicone posts designed to fit in a standard 96-well tissue culture plate. Stromal cells and hiPSC-CMs are cast in a fibrin matrix suspended between two silicone posts, forming an mEHT that produces synchronous muscle contractions. The platform presented here has the potential to be used for high throughput characterization and screening of disease phenotypes and novel therapeutics through measurements of the myocardial function, including contractile force and calcium handling, and its compatibility with immunostaining.


Asunto(s)
Células Madre Pluripotentes Inducidas , Miocitos Cardíacos , Ingeniería de Tejidos , Humanos , Ingeniería de Tejidos/métodos , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Hidrogeles/química , Diferenciación Celular , Fibrina/metabolismo , Células Cultivadas , Técnicas de Cultivo de Célula/métodos , Células del Estroma/citología , Técnicas de Cultivo de Tejidos/métodos , Técnicas de Cultivo de Tejidos/instrumentación
2.
Res Sq ; 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38699332

RESUMEN

H2O2 is a key oxidant in mammalian biology and a pleiotropic signaling molecule at the physiological level, and its excessive accumulation in conjunction with decreased cellular reduction capacity is often found to be a common pathological marker. Here, we present a red fluorescent Genetically Encoded H2O2 Indicator (GEHI) allowing versatile optogenetic dissection of redox biology. Our new GEHI, oROS-HT, is a chemigenetic sensor utilizing a HaloTag and Janelia Fluor (JF) rhodamine dye as fluorescent reporters. We developed oROS-HT through a structure-guided approach aided by classic protein structures and recent protein structure prediction tools. Optimized with JF635, oROS-HT is a sensor with 635 nm excitation and 650 nm emission peaks, allowing it to retain its brightness while monitoring intracellular H2O2 dynamics. Furthermore, it enables multi-color imaging in combination with blue-green fluorescent sensors for orthogonal analytes and low auto-fluorescence interference in biological tissues. Other advantages of oROS-HT over alternative GEHIs are its fast kinetics, oxygen-independent maturation, low pH sensitivity, lack of photo-artifact, and lack of intracellular aggregation. Here, we demonstrated efficient subcellular targeting and how oROS-HT can map inter and intracellular H2O2 diffusion at subcellular resolution. Lastly, we used oROS-HT with other green fluorescence reporters to investigate the transient effect of the anti-inflammatory agent auranofin on cellular redox physiology and calcium levels via multi-parametric, dual-color imaging.

3.
Proc Natl Acad Sci U S A ; 121(19): e2318413121, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38683993

RESUMEN

Determining the pathogenicity of hypertrophic cardiomyopathy-associated mutations in the ß-myosin heavy chain (MYH7) can be challenging due to its variable penetrance and clinical severity. This study investigates the early pathogenic effects of the incomplete-penetrant MYH7 G256E mutation on myosin function that may trigger pathogenic adaptations and hypertrophy. We hypothesized that the G256E mutation would alter myosin biomechanical function, leading to changes in cellular functions. We developed a collaborative pipeline to characterize myosin function across protein, myofibril, cell, and tissue levels to determine the multiscale effects on structure-function of the contractile apparatus and its implications for gene regulation and metabolic state. The G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 33%, resulting in more myosin heads available for contraction. Myofibrils from gene-edited MYH7WT/G256E human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) exhibited greater and faster tension development. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. We demonstrated consistent hypercontractile myosin function as a primary consequence of the MYH7 G256E mutation across scales, highlighting the pathogenicity of this gene variant. Single-cell transcriptomic and metabolic profiling demonstrated upregulated mitochondrial genes and increased mitochondrial respiration, indicating early bioenergetic alterations. This work highlights the benefit of our multiscale platform to systematically evaluate the pathogenicity of gene variants at the protein and contractile organelle level and their early consequences on cellular and tissue function. We believe this platform can help elucidate the genotype-phenotype relationships underlying other genetic cardiovascular diseases.


Asunto(s)
Miosinas Cardíacas , Cardiomiopatía Hipertrófica , Células Madre Pluripotentes Inducidas , Contracción Miocárdica , Miocitos Cardíacos , Cadenas Pesadas de Miosina , Humanos , Cadenas Pesadas de Miosina/genética , Cadenas Pesadas de Miosina/metabolismo , Miosinas Cardíacas/genética , Miosinas Cardíacas/metabolismo , Cardiomiopatía Hipertrófica/genética , Cardiomiopatía Hipertrófica/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Contracción Miocárdica/genética , Mutación , Mitocondrias/metabolismo , Mitocondrias/genética , Miofibrillas/metabolismo , Respiración de la Célula/genética
4.
Res Sq ; 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38585715

RESUMEN

Hydrogen Peroxide (H2O2) is a central oxidant in redox biology due to its pleiotropic role in physiology and pathology. However, real-time monitoring of H2O2 in living cells and tissues remains a challenge. We address this gap with the development of an optogenetic hydRogen perOxide Sensor (oROS), leveraging the bacterial peroxide binding domain OxyR. Previously engineered OxyR-based fluorescent peroxide sensors lack the necessary sensitivity and response speed for effective real-time monitoring. By structurally redesigning the fusion of Escherichia coli (E. coli) ecOxyR with a circularly permutated green fluorescent protein (cpGFP), we created a novel, green-fluorescent peroxide sensor oROS-G. oROS-G exhibits high sensitivity and fast on-and-off kinetics, ideal for monitoring intracellular H2O2 dynamics. We successfully tracked real-time transient and steady-state H2O2 levels in diverse biological systems, including human stem cell-derived neurons and cardiomyocytes, primary neurons and astrocytes, and mouse brain ex vivo and in vivo. These applications demonstrate oROS's capabilities to monitor H2O2 as a secondary response to pharmacologically induced oxidative stress and when adapting to varying metabolic stress. We showcased the increased oxidative stress in astrocytes via Aß-putriscine-MAOB axis, highlighting the sensor's relevance in validating neurodegenerative disease models. Lastly, we demonstrated acute opioid-induced generation of H2O2 signal in vivo which highlights redox-based mechanisms of GPCR regulation. oROS is a versatile tool, offering a window into the dynamic landscape of H2O2 signaling. This advancement paves the way for a deeper understanding of redox physiology, with significant implications for understanding diseases associated with oxidative stress, such as cancer, neurodegenerative, and cardiovascular diseases.

5.
bioRxiv ; 2024 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-38352381

RESUMEN

Hydrogen Peroxide (H2O2) is a central oxidant in redox biology due to its pleiotropic role in physiology and pathology. However, real-time monitoring of H2O2 in living cells and tissues remains a challenge. We address this gap with the development of an optogenetic hydRogen perOxide Sensor (oROS), leveraging the bacterial peroxide binding domain OxyR. Previously engineered OxyR-based fluorescent peroxide sensors lack the necessary sensitivity or response speed for effective real-time monitoring. By structurally redesigning the fusion of Escherichia coli (E. coli) ecOxyR with a circularly permutated green fluorescent protein (cpGFP), we created a novel, green-fluorescent peroxide sensor oROS-G. oROS-G exhibits high sensitivity and fast on-and-off kinetics, ideal for monitoring intracellular H2O2 dynamics. We successfully tracked real-time transient and steady-state H2O2 levels in diverse biological systems, including human stem cell-derived neurons and cardiomyocytes, primary neurons and astrocytes, and mouse neurons and astrocytes in ex vivo brain slices. These applications demonstrate oROS's capabilities to monitor H2O2 as a secondary response to pharmacologically induced oxidative stress, G-protein coupled receptor (GPCR)-induced cell signaling, and when adapting to varying metabolic stress. We showcased the increased oxidative stress in astrocytes via Aß-putriscine-MAOB axis, highlighting the sensor's relevance in validating neurodegenerative disease models. oROS is a versatile tool, offering a window into the dynamic landscape of H2O2 signaling. This advancement paves the way for a deeper understanding of redox physiology, with significant implications for diseases associated with oxidative stress, such as cancer, neurodegenerative disorders, and cardiovascular diseases.

6.
bioRxiv ; 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38370715

RESUMEN

H2O2 is a key oxidant in mammalian biology and a pleiotropic signaling molecule at the physiological level, and its excessive accumulation in conjunction with decreased cellular reduction capacity is often found to be a common pathological marker. Here, we present a red fluorescent Genetically Encoded H2O2 Indicator (GEHI) allowing versatile optogenetic dissection of redox biology. Our new GEHI, oROS-HT, is a chemigenetic sensor utilizing a HaloTag and Janelia Fluor (JF) rhodamine dye as fluorescent reporters. We developed oROS-HT through a structure-guided approach aided by classic protein structures and recent protein structure prediction tools. Optimized with JF635, oROS-HT is a sensor with 635 nm excitation and 650 nm emission peaks, allowing it to retain its brightness while monitoring intracellular H2O2 dynamics. Furthermore, it enables multi-color imaging in combination with blue-green fluorescent sensors for orthogonal analytes and low auto-fluorescence interference in biological tissues. Other advantages of oROS-HT over alternative GEHIs are its fast kinetics, oxygen-independent maturation, low pH sensitivity, lack of photo-artifact, and lack of intracellular aggregation. Here, we demonstrated efficient subcellular targeting and how oROS-HT can map inter and intracellular H2O2 diffusion at subcellular resolution. Lastly, we used oROS-HT with the green fluorescent calcium indicator Fluo-4 to investigate the transient effect of the anti-inflammatory agent auranofin on cellular redox physiology and calcium levels via multi-parametric, dual-color imaging.

7.
bioRxiv ; 2023 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-37333118

RESUMEN

Rationale: Over 200 mutations in the sarcomeric protein ß-myosin heavy chain (MYH7) have been linked to hypertrophic cardiomyopathy (HCM). However, different mutations in MYH7 lead to variable penetrance and clinical severity, and alter myosin function to varying degrees, making it difficult to determine genotype-phenotype relationships, especially when caused by rare gene variants such as the G256E mutation. Objective: This study aims to determine the effects of low penetrant MYH7 G256E mutation on myosin function. We hypothesize that the G256E mutation would alter myosin function, precipitating compensatory responses in cellular functions. Methods: We developed a collaborative pipeline to characterize myosin function at multiple scales (protein to myofibril to cell to tissue). We also used our previously published data on other mutations to compare the degree to which myosin function was altered. Results: At the protein level, the G256E mutation disrupts the transducer region of the S1 head and reduces the fraction of myosin in the folded-back state by 50.9%, suggesting more myosins available for contraction. Myofibrils isolated from hiPSC-CMs CRISPR-edited with G256E (MYH7 WT/G256E ) generated greater tension, had faster tension development and slower early phase relaxation, suggesting altered myosin-actin crossbridge cycling kinetics. This hypercontractile phenotype persisted in single-cell hiPSC-CMs and engineered heart tissues. Single-cell transcriptomic and metabolic profiling demonstrated upregulation of mitochondrial genes and increased mitochondrial respiration, suggesting altered bioenergetics as an early feature of HCM. Conclusions: MYH7 G256E mutation causes structural instability in the transducer region, leading to hypercontractility across scales, perhaps from increased myosin recruitment and altered crossbridge cycling. Hypercontractile function of the mutant myosin was accompanied by increased mitochondrial respiration, while cellular hypertrophy was modest in the physiological stiffness environment. We believe that this multi-scale platform will be useful to elucidate genotype-phenotype relationships underlying other genetic cardiovascular diseases.

8.
J Tissue Eng ; 13: 20417314221119628, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36003954

RESUMEN

Cardiomyopathy is currently the leading cause of death for patients with Duchenne muscular dystrophy (DMD), a severe neuromuscular disorder affecting young boys. Animal models have provided insight into the mechanisms by which dystrophin protein deficiency causes cardiomyopathy, but there remains a need to develop human models of DMD to validate pathogenic mechanisms and identify therapeutic targets. Here, we have developed human engineered heart tissues (EHTs) from CRISPR-edited, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) expressing a truncated dystrophin protein lacking part of the actin-binding domain. The 3D EHT platform enables direct measurement of contractile force, simultaneous monitoring of Ca2+ transients, and assessment of myofibril structure. Dystrophin-mutant EHTs produced less contractile force as well as delayed kinetics of force generation and relaxation, as compared to isogenic controls. Contractile dysfunction was accompanied by reduced sarcomere length, increased resting cytosolic Ca2+ levels, delayed Ca2+ release and reuptake, and increased beat rate irregularity. Transcriptomic analysis revealed clear differences between dystrophin-deficient and control EHTs, including downregulation of genes related to Ca2+ homeostasis and extracellular matrix organization, and upregulation of genes related to regulation of membrane potential, cardiac muscle development, and heart contraction. These findings indicate that the EHT platform provides the cues necessary to expose the clinically-relevant, functional phenotype of force production as well as mechanistic insights into the role of Ca2+ handling and transcriptomic dysregulation in dystrophic cardiac function, ultimately providing a powerful platform for further studies in disease modeling and drug discovery.

9.
Methods Mol Biol ; 2485: 87-97, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35618900

RESUMEN

Three-dimensional, human engineered heart tissue promotes maturation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and provides a useful platform for in vitro cardiac development and disease modeling. This protocol describes the generation of fibrin-based engineered heart tissues (EHTs) containing hiPSC-CMs and human stromal cells. The platform makes use of racks of silicone posts that fit a standard 24-well dish. Stromal cells and hiPSC-CMs are cast in a fibrin hydrogel suspended between two silicone posts, forming an engineered tissue that generates synchronous contractions. The platform described herein is amenable to various measures of cardiac function including measurement of contractile force and calcium handling, as well as molecular biology assays and immunostaining.


Asunto(s)
Células Madre Pluripotentes Inducidas , Miocitos Cardíacos , Ingeniería de Tejidos , Fibrina , Humanos , Células Madre Pluripotentes Inducidas/citología , Miocitos Cardíacos/citología , Siliconas
10.
Curr Cardiol Rep ; 24(5): 473-486, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35247166

RESUMEN

PURPOSE OF REVIEW: Human cardiac tissue engineering holds great promise for early detection of drug-related cardiac toxicity and arrhythmogenicity during drug discovery and development. We describe shortcomings of the current drug development pathway, recent advances in the development of cardiac tissue constructs as drug testing platforms, and the challenges remaining in their widespread adoption. RECENT FINDINGS: Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have been used to develop a variety of constructs including cardiac spheroids, microtissues, strips, rings, and chambers. Several ambitious studies have used these constructs to test a significant number of drugs, and while most have shown proper negative inotropic and arrhythmogenic responses, few have been able to demonstrate positive inotropy, indicative of relative hPSC-CM immaturity. Several engineered human cardiac tissue platforms have demonstrated native cardiac physiology and proper drug responses. Future studies addressing hPSC-CM immaturity and inclusion of patient-specific cell lines will further advance the utility of such models for in vitro drug development.


Asunto(s)
Células Madre Pluripotentes Inducidas , Células Madre Pluripotentes , Arritmias Cardíacas/inducido químicamente , Diferenciación Celular , Desarrollo de Medicamentos , Humanos , Miocitos Cardíacos/fisiología , Ingeniería de Tejidos
11.
Nat Commun ; 12(1): 856, 2021 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-33558528

RESUMEN

Through the efforts of many groups, a wide range of fluorescent protein reporters and sensors based on green fluorescent protein and its relatives have been engineered in recent years. Here we explore the incorporation of sensing modalities into de novo designed fluorescence-activating proteins, called mini-fluorescence-activating proteins (mFAPs), that bind and stabilize the fluorescent cis-planar state of the fluorogenic compound DFHBI. We show through further design that the fluorescence intensity and specificity of mFAPs for different chromophores can be tuned, and the fluorescence made sensitive to pH and Ca2+ for real-time fluorescence reporting. Bipartite split mFAPs enable real-time monitoring of protein-protein association and (unlike widely used split GFP reporter systems) are fully reversible, allowing direct readout of association and dissociation events. The relative ease with which sensing modalities can be incorporated and advantages in smaller size and photostability make de novo designed fluorescence-activating proteins attractive candidates for optical sensor engineering.


Asunto(s)
Proteínas Luminiscentes/metabolismo , Acetilcolina/metabolismo , Animales , Células COS , Calcio/metabolismo , Chlorocebus aethiops , Fluorescencia , Colorantes Fluorescentes/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , Proteínas Luminiscentes/química , Modelos Moleculares
12.
Protein Eng Des Sel ; 32(5): 219-230, 2019 12 31.
Artículo en Inglés | MEDLINE | ID: mdl-31769480

RESUMEN

Yeast display immunoprecipitation is a combinatorial library screening platform for the discovery and engineering of antibodies against membrane proteins using detergent-solubilized membrane fractions or cell lysates as antigen sources. Here, we present the extension of this method for the screening of antibodies that bind to membrane protein complexes, enabling discovery of antibodies that target antigens involved in a functional protein-protein interaction of interest. For this proof-of-concept study, we focused on the receptor-mediated endocytosis machinery at the blood-brain barrier, and adaptin 2 (AP-2) was chosen as the functional interaction hub. The goal of this study was to identify antibodies that bound to blood-brain barrier (BBB) membrane protein complexes containing AP-2. Screening of a nonimmune yeast display antibody library was carried out using detergent-solubilized BBB plasma membranes as an antigen pool, and antibodies that could interact with protein complexes containing AP-2 were identified. Downstream characterization of isolated antibodies confirmed targeting of proteins known to play important roles in membrane trafficking. This functional yeast display immunoprecipitation screen may be applied to other systems where antibodies against other functional classes of protein complexes are sought.


Asunto(s)
Antígenos/inmunología , Barrera Hematoencefálica/inmunología , Proteínas de la Membrana/inmunología , Complejos Multiproteicos/inmunología , Saccharomyces cerevisiae , Anticuerpos de Cadena Única , Animales , Células HEK293 , Humanos , Masculino , Ratas , Ratas Sprague-Dawley , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/inmunología , Anticuerpos de Cadena Única/genética , Anticuerpos de Cadena Única/inmunología
13.
Sci Adv ; 5(5): eaau4245, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31106264

RESUMEN

Diseases that lead to blood-brain barrier (BBB) disruption will pathologically expose normally inaccessible brain extracellular matrix (ECM) to circulating blood components. Therefore, we hypothesized that brain ECM-targeting moieties could specifically target the disrupted BBB and potentially deliver therapies. Variable lymphocyte receptors (VLRs) that preferentially associate with brain ECM were identified from an immune VLR library via yeast surface display biopanning coupled with a moderate throughput ECM screen. Brain ECM binding of VLR clones to murine and human brain tissue sections was confirmed. After systemic administration, P1C10, the lead brain ECM-targeting VLR candidate, specifically accumulated in brains with mannitol-disrupted BBB and at disrupted BBB regions in two different intracranial glioblastoma models. We also demonstrate P1C10's ability to deliver doxorubicin-loaded liposomes, leading to significantly improved survival in glioblastoma-bearing mice. Thus, VLRs can be used to selectively target pathologically exposed brain ECM and deliver drug payloads.


Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Neoplasias Encefálicas/tratamiento farmacológico , Encéfalo/metabolismo , Matriz Extracelular/metabolismo , Glioblastoma/tratamiento farmacológico , Linfocitos/metabolismo , Células 3T3 , Animales , Encéfalo/patología , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Doxorrubicina/farmacología , Glioblastoma/metabolismo , Glioblastoma/patología , Humanos , Estimación de Kaplan-Meier , Cinética , Liposomas/farmacología , Manitol/farmacología , Ratones , Ratones Endogámicos C57BL , Trasplante de Neoplasias , Conejos , Resultado del Tratamiento
14.
Pain Med ; 18(8): 1467-1475, 2017 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-28371881

RESUMEN

BACKGROUND: Chronic pain is a significant health problem strongly associated with a wide range of physical and mental health problems, including addiction. The widespread prevalence of pain and the increasing rate of opioid prescriptions have led to a focus on how physicians are educated about chronic pain. This critical scoping review describes the current literature in this important area, identifying gaps and suggesting avenues for further research starting from patients' standpoint. METHODS: A search of the ERIC, MEDLINE, and Social Sciences Abstracts databases, as well as 10 journals related to medical education, was conducted to identify studies of the training of medical students, residents, and fellows in chronic noncancer pain. RESULTS: The database and hand-searches identified 545 articles; of these, 39 articles met inclusion criteria and underwent full review. Findings were classified into four inter-related themes. We found that managing chronic pain has been described as stressful by trainees, but few studies have investigated implications for their well-being or ability to provide empathetic care. Even fewer studies have investigated how educational strategies impact patient care. We also note that the literature generally focuses on opioids and gives less attention to education in nonpharmacological approaches as well as nonopioid medications. DISCUSSION: The findings highlight significant discrepancies between the prevalence of chronic pain in society and the low priority assigned to educating future physicians about the complexities of pain and the social context of those afflicted. This suggests the need for better pain education as well as attention to the "hidden curriculum."


Asunto(s)
Analgésicos Opioides/uso terapéutico , Dolor Crónico/tratamiento farmacológico , Educación Médica , Mal Uso de los Servicios de Salud/prevención & control , Manejo del Dolor/métodos , Humanos
15.
Plant Cell Environ ; 39(8): 1818-34, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27038434

RESUMEN

Eutrema salsugineum, a halophytic relative of Arabidopsis thaliana, was subjected to varying phosphate (Pi) treatments. Arabidopsis seedlings grown on 0.05 mm Pi displayed shortened primary roots, higher lateral root density and reduced shoot biomass allocation relative to those on 0.5 mm Pi, whereas Eutrema seedlings showed no difference in lateral root density and shoot biomass allocation. While a low Fe concentration mitigated the Pi deficiency response for Arabidopsis, Eutrema root architecture was unaltered, but adding NaCl increased Eutrema lateral root density almost 2-fold. Eutrema and Arabidopsis plants grown on soil without added Pi for 4 weeks had low shoot and root Pi content. Pi-deprived, soil-grown Arabidopsis plants were stunted with senescing older leaves, whereas Eutrema plants were visually indistinguishable from 2.5 mm Pi-supplemented plants. Genes associated with Pi starvation were analysed by RT-qPCR. EsIPS2, EsPHT1;4 and EsPAP17 showed up-regulated expression in Pi-deprived Eutrema plants, while EsPHR1, EsWRKY75 and EsRNS1 showed no induction. Absolute quantification of transcripts indicated that PHR1, WRKY75 and RNS1 were expressed at higher levels in Eutrema plants relative to those in Arabidopsis regardless of external Pi. The low phenotypic plasticity Eutrema displays to Pi supply is consistent with adaptation to chronic Pi deprivation in its extreme natural habitat.


Asunto(s)
Aclimatación , Brassicaceae/metabolismo , Extremófilos/metabolismo , Regulación de la Expresión Génica de las Plantas , Fosfatos/deficiencia , Brassicaceae/genética , Brassicaceae/crecimiento & desarrollo , Genes de Plantas , Hierro/metabolismo , Fenotipo , Salinidad , Plantones/crecimiento & desarrollo
16.
Healthc Policy ; 9(3): 55-66, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24726074

RESUMEN

BACKGROUND: Ontario has introduced strategies over the past decade to reduce wait times and length of stay and improve access to physiotherapy for orthopaedic and other patients. The aim of this study is to explore patients' experiences of joint replacement care during a significant system change in their care setting. METHODS: A secondary analysis was done on semi-structured qualitative interviews that were conducted in 2009 with 12 individuals who had undergone at least two hip or knee replacements five years apart at a specialized orthopaedic centre in Ontario, Canada. Interview transcripts were coded and then organized into themes. RESULTS: Although the original study aimed to capture participants' experiences with changes in anaesthetic technique between their first and second joint replacements, the participants described several unrelated differences in the care they received during this period. For example, participants had difficulty obtaining a referral to an orthopaedic surgeon from their family physician. They also noted that the hospital stay and in-hospital physiotherapy they received were shorter after the second joint replacement surgery. They identified guidance from physiotherapists as an important component of their recovery, but sometimes had difficulty arranging physiotherapy after hospital discharge following their most recent surgery. CONCLUSIONS: The changes described between the first and second joint replacements provide the participants' perspective on the impact of policy changes on wait times, reduced lengths of hospital stay and physiotherapy access. The impact of these policy changes, often made in an attempt to improve access to care, had an unintended and detrimental effect on participants' perceptions and experiences of the quality of care provided.


Asunto(s)
Artroplastia de Reemplazo de Cadera/rehabilitación , Artroplastia de Reemplazo de Rodilla/rehabilitación , Satisfacción del Paciente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Reforma de la Atención de Salud , Accesibilidad a los Servicios de Salud , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Ontario , Modalidades de Fisioterapia , Investigación Cualitativa
17.
BMC Health Serv Res ; 13: 531, 2013 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-24359110

RESUMEN

BACKGROUND: Patient-centered care ideally considers patient preferences, values and needs. However, it is unclear if policies such as wait time strategies for hip and knee replacement surgery (TJR) are patient-centred as they focus on an isolated episode of care. This paper describes the accounts of people scheduled to undergo TJR, focusing on their experience of (OA) as a chronic disease that has considerable impact on their everyday lives. METHODS: Semi-structured qualitative interviews were conducted with participants scheduled to undergo TJR who were recruited from the practices of two orthopaedic surgeons. We first used maximum variation and then theoretical sampling based on age, sex and joint replaced. 33 participants (age 38-79 years; 17 female) were included in the analysis. 20 were scheduled for hip replacement and 13 for knee replacement. A constructivist approach to grounded theory guided sampling, data collection and analysis. RESULTS: While a specific hip or knee was the target for surgery, individuals experienced multiple-joint symptoms and comorbidities. Management of their health and daily lives was impacted by these combined experiences. Over time, they struggled to manage symptoms with varying degrees of access to and acceptance of pain medication, which was a source of constant concern. This was a multi-faceted issue with physicians reluctant to prescribe and many patients reluctant to take prescription pain medications due to their side effects. CONCLUSIONS: For patients, TJR surgery is an acute intervention in the experience of chronic disease, OA and other comorbidities. While policy has focused on wait time as patient/surgeon decision for surgery to surgery date, the patient's experience does not begin or end with surgery as they struggle to manage their pain. Our findings suggest that further work is needed to align the medical treatment of OA with the current policy emphasis on patient-centeredness. Patient-centred care may require a paradigm shift that is not always evident in current policy and strategies.


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Modelos Organizacionales , Atención Dirigida al Paciente , Actividades Cotidianas/psicología , Adulto , Anciano , Artroplastia de Reemplazo de Cadera/psicología , Artroplastia de Reemplazo de Cadera/normas , Artroplastia de Reemplazo de Rodilla/psicología , Artroplastia de Reemplazo de Rodilla/normas , Dolor Crónico/psicología , Femenino , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Manejo del Dolor/psicología , Manejo del Dolor/normas , Atención Dirigida al Paciente/organización & administración , Atención Dirigida al Paciente/normas , Investigación Cualitativa , Derivación y Consulta/estadística & datos numéricos , Factores de Tiempo
18.
J Multidiscip Healthc ; 5: 249-56, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23055744

RESUMEN

PURPOSE: Hospitalists specialize in the management of hospitalized patients. They work with several health care professionals to provide patient care. There has been little research examining the perceived impact of the hospitalist's role on staff working in an orthopedic environment. This study examined the experiences of staff across several professional backgrounds in working with a hospitalist in an orthopedic environment. PARTICIPANTS AND METHODS: A qualitative descriptive approach was taken to investigate the experience of staff working with a hospitalist at a specialized orthopedic hospital. Purposive sampling was used to recruit interview participants including nurses, internists, pharmacists, physiotherapists, anesthetists, senior administration, and orthopedic surgeons to the point of theoretical saturation, which occurred after 12 interviews. Interviews were coded, and these codes were combined into categories and predominant themes were identified. FINDINGS: Overall, staff believed that the hospitalist role was a positive addition to the facility. The role benefitted patients and supported the clinical well-being and education of staff. Many staff felt the hospitalist had no impact on their workload, but others reported that their work had decreased or increased. Several described the potential for role overlap between the hospitalist and other physicians. CONCLUSION: The importance of interprofessional collaboration in the implementation of the hospitalist role was a recurring theme in our analysis. This study demonstrates the importance of educating staff about the hospitalist role boundaries prior to implementing hospitalist care.

19.
J Opioid Manag ; 8(3): 145-52, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22798174

RESUMEN

OBJECTIVE: Most total knee arthroplasty (TKA) recipients experience pain following the procedure. Patients are provided with medications to manage pain but there is little information regarding their usage of analgesics after hospital discharge. This study investigated analgesic usage in recent TKA recipients. DESIGN AND PARTICIPANTS: A qualitative descriptive approach was taken to produce a summary of the experiences of 14 participants. Purposive sampling methods were used during recruitment. One semistructured interview was conducted with each participant. Interviewing continued until theoretical saturation was reached. RESULTS: Most participants used less medication than was prescribed and stopped taking prescription analgesics before requiring a renewal. Participants adjusted their usage in response to pain, adverse effects, advice from their family and healthcare providers, fears of becoming "hooked," and a general dislike of taking medications. CONCLUSIONS: Patient modifications to medication regimens are often labeled as patient nonadherence; however, participants in this study considered their actions to be adaptive. This conceptual distinction has practical implications for healthcare providers. These findings emphasize the importance of having TKA patients develop their pain management regimen in conjunction with healthcare providers so that regimens can be tailored to individual needs.


Asunto(s)
Analgésicos Opioides/uso terapéutico , Analgésicos/uso terapéutico , Artroplastia de Reemplazo de Rodilla , Manejo del Dolor/métodos , Dolor Postoperatorio/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Analgésicos/administración & dosificación , Analgésicos Opioides/administración & dosificación , Interpretación Estadística de Datos , Prescripciones de Medicamentos , Familia , Miedo/psicología , Femenino , Personal de Salud , Humanos , Masculino , Manejo del Dolor/psicología , Cooperación del Paciente , Educación del Paciente como Asunto , Selección de Paciente , Encuestas y Cuestionarios , Población Urbana
20.
Reg Anesth Pain Med ; 36(5): 461-5, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21857265

RESUMEN

BACKGROUND AND OBJECTIVES: It is reported that patients continue to have misgivings about regional anesthesia (RA) despite strong evidence to support its use for hip and knee replacement surgery. To date, no one has had an opportunity to study the experiences of patients who have undergone both types of anesthesia for these procedures. METHODS: Using descriptive qualitative methods, 12 patients who had hip or knee replacements under both RA and GA at two different time points (excluding revisions) were interviewed using purposeful sampling until saturation had been reached. Following transcription of each tape, a small study team met over the course of several months to read and discuss each transcript. A coding template was developed, and emerging themes noted. RESULTS: For the majority of patients, RA was either well tolerated or preferred. Having a previous negative experience with general anesthesia was common and was strongly associated with a patient's satisfaction with RA. Patients also described being highly influenced by the preference of their surgeon. CONCLUSIONS: These findings have important implications. First, many patients were surprisingly neutral about the procedure and seemed more fearful of anesthesia in general rather than of either technique specifically. This finding, combined with patient's influence by clinician preference, underscores the importance of physician support for RA. Some participants identified one of their misgivings about RA as being fear of being awake, which is consistent with the medical literature. Our findings also support the idea that from a patient's perspective, appropriate sedation while undergoing RA may be important.


Asunto(s)
Anestesia de Conducción/psicología , Artroplastia de Reemplazo de Cadera/psicología , Artroplastia de Reemplazo de Rodilla/psicología , Medicina Basada en la Evidencia/normas , Conocimientos, Actitudes y Práctica en Salud , Satisfacción del Paciente , Adulto , Anciano , Anciano de 80 o más Años , Anestesia de Conducción/métodos , Artroplastia de Reemplazo de Cadera/métodos , Artroplastia de Reemplazo de Rodilla/métodos , Medicina Basada en la Evidencia/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad
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