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1.
Cell ; 139(5): 969-82, 2009 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-19945380

RESUMEN

Neural progenitors generate distinct cell types at different stages, but the mechanisms controlling these temporal transitions are poorly understood. In the Drosophila CNS, a cascade of transcription factors, the "temporal gene cascade," has been identified that acts to alter progenitor competence over time. However, many CNS lineages display broad temporal windows, and it is unclear how broad windows progress into subwindows that generate unique cell types. We have addressed this issue in an identifiable Drosophila CNS lineage and find that a broad castor temporal window is subdivided by two different feed-forward loops, both of which are triggered by castor itself. The first loop acts to specify a unique cell fate, whereas the second loop suppresses the first loop, thereby allowing for the generation of alternate cell fates. This mechanism of temporal and "subtemporal" genes acting in opposing feed-forward loops may be used by many stem cell lineages to generate diversity.


Asunto(s)
Drosophila melanogaster/citología , Ganglios de Invertebrados/citología , Redes Reguladoras de Genes , Neuronas/citología , Animales , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Regulación del Desarrollo de la Expresión Génica , Neuronas/metabolismo , Proteínas Represoras/metabolismo , Células Madre/citología , Factores de Transcripción/metabolismo
2.
Toxicol Ind Health ; 39(6): 313-324, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37134012

RESUMEN

A sampling chamber was developed for emission testing of diisocyanates, methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and corresponding diamines, methylene diphenyl diamine (MDA), and toluene diamine (TDA) from polyurethane (PU) product surfaces. In addition, a methodology for validation of the sampling chamber was presented, based on the introduction of generated standard atmospheres of the different diisocyanates and diamines to the sampling chamber system. Sampling of diisocyanates and diamines was performed on a circular glass fiber filter (150 mm diameter) impregnated with dihexyl amine (DHA) and acetic acid (AA) positioned inside a cylindrical stainless steel sampling chamber. The diisocyanates were immediately derivatized to DHA derivatives, and the amines were derivatized in a subsequent work-up procedure with ethyl chloroformate (ECF). The design of the sampling chamber and the presented methodology allowed for simultaneous sampling and analysis of diisocyanates and diamines of emission from a large surface area with minimal interior wall interaction in the sampling chamber. Performance characteristics of the sampling chamber for different sampling times and air humidity were obtained by determining collected amounts of the diisocyanates and diamines in the different parts of the sampling chamber. The repeatability of the collected amount on the impregnated filters in the sampling chamber was 15% with an overall recovery for 8 h of sampling in the range of 61% to 96%. The performance of the sampling chamber was not affected by air humidity (5%-75% RH), and no breakthrough during sampling was observed. LC-MS/MS determinations allowed for emission testing of diisocyanates and diamines on product surfaces as low as 10-30 ng m-2 h-1.


Asunto(s)
Poliuretanos , 2,4-Diisocianato de Tolueno , Diaminas , Cromatografía Liquida , Espectrometría de Masas en Tándem , Isocianatos , 2,4-Diisocianato de Tolueno/análisis , Aminas
3.
Toxicol Ind Health ; 39(6): 298-312, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37145999

RESUMEN

Performing risk assessments (RA) on household use of flexible polyurethane (PU) foams requires access to reliable data about emission and migration of potential diamine impurities. A toluene diisocyanate (TDI) and a methylene diphenyl diisocyanate (MDI) based foam were thermally treated to enable measurements on samples with defined concentrations of the corresponding diamines, toluene diamine (TDA), and methylene dianiline (MDA). The thermally treated foams used for emission testing contained up to 15 mg.kg-1 of TDA and 27 mg.kg-1 of MDA. Those used for migration testing contained 5.1 mg.kg-1 of TDA and 14.1 mg.kg-1 of MDA. Stability of the thermally generated diamines was sufficient for testing over a 37-day period. Analytical techniques that did not decompose the polymer matrix were applied. Emission rates for TDA and MDA isomers were less than the limit of quantitation (LOQ) of 0.008-0.07 µg.m-2.h-1. Migration was studied using samples of the same thermally treated foams over a 35-day period. Quantifiable migration of MDA from the MDI-based foam was only observed on Days 1 and 2. From Day 3 onward, migration rates were less than the LOQ. Quantifiable migration of TDA from the TDI-based foam rapidly decreased with time and was only observed on Days 1 thru 3. From Day 4 onward, migration rates were less than the LOQ. Theoretically, the migration rate should be inversely proportional to the square root of time (t) as t-0.5. This relationship was confirmed by the experimental data and enables extrapolating migration values to more extended time periods to conduct RAs.


Asunto(s)
Exposición Profesional , 2,4-Diisocianato de Tolueno , Poliuretanos , Diaminas , 2,4-Diisocianato de Tolueno/análisis , Aminas , Exposición Profesional/análisis
4.
Toxicol Ind Health ; 38(9): 643-652, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35319330

RESUMEN

The aim of this study was to provide realistic isocyanate and amine emission data when using different methylene diphenyl diisocyanate (MDI)-based polyurethane consumer products. Emission testing (air sampling) of diisocyanates and corresponding diamines was performed in a full-scale controlled-environment chamber during different work operations, such as gluing, mixing and foaming. The polyurethane products used were construction glue, one-component foam and two different two-component adhesives used in parquet flooring. Air sampling for isocyanates and amines was performed in the breathing zone of the worker and at different positions inside the controlled-environment chamber while the work operations were performed. Air sampling was also performed after the application, at different positions inside the chamber, to cover the post curing phase. Low air concentrations (0.1-0.7 µg MDI/m3, 0.03-0.2 µg isocyanate group (NCO)/m3) were found in the breathing zone and close to the work operation for some of the gluing applications. No methylene diphenyl diamine (MDA) concentrations above the limit of quantification were found for any of the applications in the breathing zone air. These results indicated that inhalation exposure to MDA or MDI would be expected to be minimal during application of do-it-yourself consumer products containing MDI.


Asunto(s)
Contaminantes Ocupacionales del Aire , Exposición Profesional , Aerosoles , Contaminantes Ocupacionales del Aire/análisis , Isocianatos , Exposición Profesional/análisis , Poliuretanos/análisis
5.
Phys Rev Lett ; 127(3): 036402, 2021 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-34328754

RESUMEN

The interaction of electrons with quantized phonons and photons underlies the ultrafast dynamics of systems ranging from molecules to solids, and it gives rise to a plethora of physical phenomena experimentally accessible using time-resolved techniques. Green's function methods offer an invaluable interpretation tool since scattering mechanisms of growing complexity can be selectively incorporated in the theory. Currently, however, real-time Green's function simulations are either prohibitively expensive due to the cubic scaling with the propagation time or do neglect the feedback of electrons on the bosons, thus violating energy conservation. We put forward a computationally efficient Green's function scheme which overcomes both limitations. The numerical effort scales linearly with the propagation time while the simultaneous dressing of electrons and bosons guarantees the fulfillment of all fundamental conservation laws. We present a real-time study of the phonon-driven relaxation dynamics in an optically excited narrow band-gap insulator, highlighting the nonthermal behavior of the phononic degrees of freedom. Our formulation paves the way to first-principles simulations of electron-boson systems with unprecedented long propagation times.

6.
J Electrocardiol ; 50(2): 176-183, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28012557

RESUMEN

OBJECTIVES: We investigated arrhythmia, electrocardiography and physical work capacity (PWC) in the follow-up of ARVC. DESIGN: Twenty-three patients (13 men; age 41±12years) fulfilling diagnostic criteria were re-investigated after at least five years. RESULTS: Ventricular arrhythmia during exercise testing (ET) was present in 14 patients (61%) and showed variation between examinations. In eleven (48%), complex ventricular ectopic activity was observed at peak exercise or immediately thereafter. Mutations known to be pathogenic in ARVC were present in 13 patients (57%) of which 11 developed complex ventricular arrhythmia at ET. PWC at baseline was 190±66W (104±26%) decreasing to 151±61W (91±23%, p=0.008) after 10.7years. CONCLUSION: The appearance of ventricular arrhythmia during exercise testing showed temporal variation but was frequent in patients with relevant genetic mutation. Physical exercise capacity decreased over time in patients with ARVC in excess to the age-related deterioration and regardless of medication.


Asunto(s)
Displasia Ventricular Derecha Arritmogénica/diagnóstico , Displasia Ventricular Derecha Arritmogénica/fisiopatología , Electrocardiografía/métodos , Prueba de Esfuerzo/métodos , Tolerancia al Ejercicio , Adulto , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Pronóstico , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
7.
Comput Inform Nurs ; 34(8): 360-8, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27223309

RESUMEN

Telehealth programs for heart failure have been studied using a variety of techniques. Because currently a majority of the elderly are nonusers of computers and Internet, we developed a home telehealth system based on digital pen technology. Fourteen patients (mean age, 84 years [median, 83 years]) with severe heart failure participated in a 13-month pilot study in specialized homecare. Participants communicated patient-reported outcome measures daily using the digital pen and health diary forms, submitting a total of 3 520 reports. The reports generated a total of 632 notifications when reports indicated worsening health. Healthcare professionals reviewed reports frequently, more than 4700 times throughout the study, and acted on the information provided. Patients answered questionnaires and were observed in their home environment when using the system. Results showed that the technology was accepted by participants: patients experienced an improved contact with clinicians; they felt more compliant with healthcare professionals' advice, and they felt more secure and more involved in their own care. Via the system, the healthcare professionals detected heart failure-related deteriorations at an earlier stage, and as a consequence, none of the patients were admitted into hospital care during the study.


Asunto(s)
Insuficiencia Cardíaca/terapia , Servicios de Atención de Salud a Domicilio , Internet , Registros Médicos , Consulta Remota/métodos , Telemedicina/métodos , Anciano , Anciano de 80 o más Años , Diseño de Equipo , Personal de Salud , Humanos , Informática Médica , Cooperación del Paciente/psicología , Proyectos Piloto , Consulta Remota/instrumentación , Autoinforme , Encuestas y Cuestionarios
8.
Development ; 139(4): 678-89, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22241838

RESUMEN

During neural lineage progression, differences in daughter cell proliferation can generate different lineage topologies. This is apparent in the Drosophila neuroblast 5-6 lineage (NB5-6T), which undergoes a daughter cell proliferation switch from generating daughter cells that divide once to generating neurons directly. Simultaneously, neural lineages, e.g. NB5-6T, undergo temporal changes in competence, as evidenced by the generation of different neural subtypes at distinct time points. When daughter proliferation is altered against a backdrop of temporal competence changes, it may create an integrative mechanism for simultaneously controlling cell fate and number. Here, we identify two independent pathways, Prospero and Notch, which act in concert to control the different daughter cell proliferation modes in NB5-6T. Altering daughter cell proliferation and temporal progression, individually and simultaneously, results in predictable changes in cell fate and number. This demonstrates that different daughter cell proliferation modes can be integrated with temporal competence changes, and suggests a novel mechanism for coordinately controlling neuronal subtype numbers.


Asunto(s)
Diferenciación Celular/fisiología , Linaje de la Célula/fisiología , Proliferación Celular , Drosophila melanogaster/citología , Drosophila melanogaster/fisiología , Neuronas/citología , Neuronas/fisiología , Animales , Animales Modificados Genéticamente , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , FMRFamida/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Receptores Notch/genética , Receptores Notch/metabolismo , Transducción de Señal/fisiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
9.
Ann Occup Hyg ; 58(3): 340-54, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24371044

RESUMEN

An advanced design of a denuder impactor (DI) sampler has been developed for characterization of possible airborne isocyanate exposure in different particle size fractions. The sampler is equipped with 12 different parallel denuder tubes, 4 impaction stages with the cut-off values (d50) of: 9.5, 4, 2.5 and 1 µm, and an end filter that collects particles < 1 µm. All collecting parts were impregnated with di-n-butylamine DBA as the reagent in a mixture with acetic acid. The performance of the DI sampler was studied on a standard atmosphere containing gas and particulate isocyanates. The isocyanate atmosphere was generated by liquid permeation of 2,4-, 2,6-Toluene Diisocyanate (TDI), 1,6-Hexamethylene Diisocyanate (HDI) and Isophorone Diisocyanate (IPDI). 4,4'-Methylene Diphenyl Diisocyanate (MDI) particles were generated by heating of technical MDI and condensing the mixture of gas and particle-borne MDI in an atmosphere containing mixed salt particles. The study was performed in a 0.85 m3 environmental chamber with stainless steel walls. With the advancement of the DI sampler it is now possible to collect isocyanate particle samples for up to 320 min. The performance of the DI sampler is essentially unaffected by the humidity. The DI sampler and the ASSET EZ4-NCO sampler (Sigma-Aldrich/Supelco, Bellefonte, PA, USA) gave similar results. Sample losses within the DI sampler are low. In the environmental chamber it was observed that the particle distribution may be affected by the humidity and ageing. A scanning mobility particle sizer (SMPS) was used to separate a flow of selected fractions containing MDI particles from mixed MDI and salt particles. The particle-size distribution had a maximum at about 300 nm, but later in the environmental chamber 1 µm dominated. The distribution was very different as compared to with only NaCl or MDI present. The biological relevance for studying isocyanate nano particles is significant as these have the possibility to reach the lower airways where allergic reactions may occur. SMPS and isocyanate air sampling can be used for the investigation of isocyanate nano particles.


Asunto(s)
Contaminantes Ocupacionales del Aire/análisis , Monitoreo del Ambiente/métodos , Exposición por Inhalación/análisis , Isocianatos/análisis , Aerosoles/análisis , Monitoreo del Ambiente/instrumentación , Humanos , Humedad , Nanopartículas/análisis , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Tamaño de la Partícula
10.
Ann Occup Hyg ; 58(1): 28-49, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23960047

RESUMEN

The performance of a dry sampler, with an impregnated denuder in series with a glass fibre filter, using di-n-butylamine (DBA) for airborne isocyanates (200ml min(-1)) is investigated and compared with an impinger flask with a glass fibre filter in series (1 l min(-1)). An exposure chamber containing 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 2,4- and 2,6-toluene diisocyanate (TDI) in the concentration range of 5-205 µg m(-3) [0.7-33 p.p.b.; relative humidity (RH) 50%], generated by gas- and liquid-phase permeation, was used for the investigation. The precision for the dry sampling for five series with eight samplers were in the range of 2.0-6.1% with an average of 3.8%. During 120-min sampling (n = 4), no breakthrough was observed when analysing samplers in series. Sixty-four exposed samplers were analysed after storage for 0, 7, 14, and 21 days. No breakdown of isocyanate derivatives was observed. Twenty-eight samplers in groups of eight were collecting isocyanates during 0.5-32h. Virtually linear relationships were obtained with regard to sampling time and collected isocyanates with correlation coefficients in the range of 0.998-0.999 with the intercept close to the origin. Pre- or post-exposure to ambient air did not affect the result. Dry sampling (n = 48) with impinger-filter sampling (n = 48) of thermal decomposition product of polyurethane polymers, at RH 20, 40, 60, and 90%, was compared for 11 isocyanate compounds. The ratio between the different isocyanates collected with dry samplers and impinger-filter samplers was in the range of 0.80-1.14 for RH = 20%, 0.8-1.25 for RH = 40%, 0.76-1.4 for RH = 60%, and 0.72-3.7 for RH = 90%. Taking into account experimental errors, it seems clear that isocyanic acid DBA derivatives are found at higher levels in the dry samples compared with impinger-filter samplers at elevated humidity. The dry sampling using DBA as the reagent enables easy and robust sampling without the need of field extraction.


Asunto(s)
Contaminantes Ocupacionales del Aire/análisis , Monitoreo del Ambiente/métodos , Isocianatos/análisis , Aerosoles/análisis , Cromatografía Liquida , Monitoreo del Ambiente/instrumentación , Monitoreo del Ambiente/normas , Humanos , Exposición Profesional/análisis , Espectrometría de Masas en Tándem , Factores de Tiempo
11.
PLoS Genet ; 7(10): e1002302, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22046139

RESUMEN

Protein function is encoded within protein sequence and protein domains. However, how protein domains cooperate within a protein to modulate overall activity and how this impacts functional diversification at the molecular and organism levels remains largely unaddressed. Focusing on three domains of the central class Drosophila Hox transcription factor AbdominalA (AbdA), we used combinatorial domain mutations and most known AbdA developmental functions as biological readouts to investigate how protein domains collectively shape protein activity. The results uncover redundancy, interactivity, and multifunctionality of protein domains as salient features underlying overall AbdA protein activity, providing means to apprehend functional diversity and accounting for the robustness of Hox-controlled developmental programs. Importantly, the results highlight context-dependency in protein domain usage and interaction, allowing major modifications in domains to be tolerated without general functional loss. The non-pleoitropic effect of domain mutation suggests that protein modification may contribute more broadly to molecular changes underlying morphological diversification during evolution, so far thought to rely largely on modification in gene cis-regulatory sequences.


Asunto(s)
Tipificación del Cuerpo/genética , Sistema Nervioso Central/embriología , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Animales , Linaje de la Célula/genética , Sistema Nervioso Central/crecimiento & desarrollo , Proteínas de Unión al ADN/genética , Proteínas de Drosophila/química , Drosophila melanogaster/embriología , Drosophila melanogaster/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Estudios de Asociación Genética , Mutación , Proteínas Nucleares/química , Estructura Terciaria de Proteína/genética , Factores de Transcripción/química , Proteína Wnt1/genética , Proteína Wnt1/metabolismo
12.
PLoS Biol ; 8(5): e1000368, 2010 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-20485487

RESUMEN

The generation of distinct neuronal subtypes at different axial levels relies upon both anteroposterior and temporal cues. However, the integration between these cues is poorly understood. In the Drosophila central nervous system, the segmentally repeated neuroblast 5-6 generates a unique group of neurons, the Apterous (Ap) cluster, only in thoracic segments. Recent studies have identified elaborate genetic pathways acting to control the generation of these neurons. These insights, combined with novel markers, provide a unique opportunity for addressing how anteroposterior and temporal cues are integrated to generate segment-specific neuronal subtypes. We find that Pbx/Meis, Hox, and temporal genes act in three different ways. Posteriorly, Pbx/Meis and posterior Hox genes block lineage progression within an early temporal window, by triggering cell cycle exit. Because Ap neurons are generated late in the thoracic 5-6 lineage, this prevents generation of Ap cluster cells in the abdomen. Thoracically, Pbx/Meis and anterior Hox genes integrate with late temporal genes to specify Ap clusters, via activation of a specific feed-forward loop. In brain segments, "Ap cluster cells" are present but lack both proper Hox and temporal coding. Only by simultaneously altering Hox and temporal gene activity in all segments can Ap clusters be generated throughout the neuroaxis. This study provides the first detailed analysis, to our knowledge, of an identified neuroblast lineage along the entire neuroaxis, and confirms the concept that lineal homologs of truncal neuroblasts exist throughout the developing brain. We furthermore provide the first insight into how Hox/Pbx/Meis anteroposterior and temporal cues are integrated within a defined lineage, to specify unique neuronal identities only in thoracic segments. This study reveals a surprisingly restricted, yet multifaceted, function of both anteroposterior and temporal cues with respect to lineage control and cell fate specification.


Asunto(s)
Diferenciación Celular , Sistema Nervioso Central/citología , Drosophila/citología , Regulación del Desarrollo de la Expresión Génica , Neuronas/citología , Células Madre/citología , Abdomen/fisiología , Animales , Encéfalo/citología , Drosophila/crecimiento & desarrollo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Neuronas/metabolismo , Células Madre/metabolismo , Tórax/citología
13.
BMC Med Inform Decis Mak ; 13: 57, 2013 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-23656624

RESUMEN

BACKGROUND: The openEHR project and the closely related ISO 13606 standard have defined structures supporting the content of Electronic Health Records (EHRs). However, there is not yet any finalized openEHR specification of a service interface to aid application developers in creating, accessing, and storing the EHR content.The aim of this paper is to explore how the Representational State Transfer (REST) architectural style can be used as a basis for a platform-independent, HTTP-based openEHR service interface. Associated benefits and tradeoffs of such a design are also explored. RESULTS: The main contribution is the formalization of the openEHR storage, retrieval, and version-handling semantics and related services into an implementable HTTP-based service interface. The modular design makes it possible to prototype, test, replicate, distribute, cache, and load-balance the system using ordinary web technology. Other contributions are approaches to query and retrieval of the EHR content that takes caching, logging, and distribution into account. Triggering on EHR change events is also explored.A final contribution is an open source openEHR implementation using the above-mentioned approaches to create LiU EEE, an educational EHR environment intended to help newcomers and developers experiment with and learn about the archetype-based EHR approach and enable rapid prototyping. CONCLUSIONS: Using REST addressed many architectural concerns in a successful way, but an additional messaging component was needed to address some architectural aspects. Many of our approaches are likely of value to other archetype-based EHR implementations and may contribute to associated service model specifications.


Asunto(s)
Registros Electrónicos de Salud , Programas Informáticos , Simulación por Computador , Humanos , Integración de Sistemas
14.
JMIR Med Inform ; 11: e46477, 2023 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-37523221

RESUMEN

BACKGROUND: There is a flora of health care information models but no consensus on which to use. This leads to poor information sharing and duplicate modelling work. The amount and type of differences between models has, to our knowledge, not been evaluated. OBJECTIVE: This work aims to explore how information structured with various information models differ in practice. Our hypothesis is that differences between information models are overestimated. This work will also assess the usability of competency questions as a method for evaluation of information models within health care. METHODS: In this study, 4 information standards, 2 standards for secondary use, and 2 electronic health record systems were included as material. Competency questions were developed for a random selection of recommendations from a clinical guideline. The information needed to answer the competency questions was modelled according to each included information model, and the results were analyzed. Differences in structure and terminology were quantified for each combination of standards. RESULTS: In this study, 36 competency questions were developed and answered. In general, similarities between the included information models were larger than the differences. The demarcation between information model and terminology was overall similar; on average, 45% of the included structures were identical between models. Choices of terminology differed within and between models; on average, 11% was usable in interaction with each other. The information models included in this study were able to represent most information required for answering the competency questions. CONCLUSIONS: Different but same same; in practice, different information models structure much information in a similar fashion. To increase interoperability within and between systems, it is more important to move toward structuring information with any information model rather than finding or developing a perfect information model. Competency questions are a feasible way of evaluating how information models perform in practice.

15.
Diabetes ; 72(10): 1350-1363, 2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-36580483

RESUMEN

Increased saturated fatty acid (SFA) levels in membrane phospholipids have been implicated in the development of metabolic disease. Here, we tested the hypothesis that increased SFA content in cell membranes negatively impacts adipocyte insulin signaling. Preadipocyte cell models with elevated SFA levels in phospholipids were generated by disrupting the ADIPOR2 locus, which resulted in a striking twofold increase in SFA-containing phosphatidylcholines and phosphatidylethanolamines, which persisted in differentiated adipocytes. Similar changes in phospholipid composition were observed in white adipose tissues isolated from the ADIPOR2-knockout mice. The SFA levels in phospholipids could be further increased by treating ADIPOR2-deficient cells with palmitic acid and resulted in reduced membrane fluidity and endoplasmic reticulum stress in mouse and human preadipocytes. Strikingly, increased SFA levels in differentiated adipocyte phospholipids had no effect on adipocyte gene expression or insulin signaling in vitro. Similarly, increased adipocyte phospholipid saturation did not impair white adipose tissue function in vivo, even in mice fed a high-saturated fat diet at thermoneutrality. We conclude that increasing SFA levels in adipocyte phospholipids is well tolerated and does not affect adipocyte insulin signaling in vitro and in vivo.


Asunto(s)
Insulina , Fosfolípidos , Ratones , Humanos , Animales , Insulina/metabolismo , Adipocitos/metabolismo , Ácidos Grasos/metabolismo , Membrana Celular/metabolismo , Proteínas Portadoras/metabolismo
16.
Biomedicines ; 10(2)2022 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-35203411

RESUMEN

Dapagliflozin is a sodium-glucose co-transporter 2 (SGLT2) inhibitor used for the treatment of diabetes. This study examines the effects of dapagliflozin on human islets, focusing on alpha and beta cell composition in relation to function in vivo, following treatment of xeno-transplanted diabetic mice. Mouse beta cells were ablated by alloxan, and dapagliflozin was provided in the drinking water while controls received tap water. Body weight, food and water intake, plasma glucose, and human C-peptide levels were monitored, and intravenous arginine/glucose tolerance tests (IVarg GTT) were performed to evaluate islet function. The grafted human islets were isolated at termination and stained for insulin, glucagon, Ki67, caspase 3, and PDX-1 immunoreactivity in dual and triple combinations. In addition, human islets were treated in vitro with dapagliflozin at different glucose concentrations, followed by insulin and glucagon secretion measurements. SGLT2 inhibition increased the animal survival rate and reduced plasma glucose, accompanied by sustained human C-peptide levels and improved islet response to glucose/arginine. SGLT2 inhibition increased both alpha and beta cell proliferation (Ki67+glucagon+ and Ki67+insulin+) while apoptosis was reduced (caspase3+glucagon+ and caspase3+insulin+). Alpha cells were fewer following inhibition of SGLT2 with increased glucagon/PDX-1 double-positive cells, a marker of alpha to beta cell transdifferentiation. In vitro treatment of human islets with dapagliflozin had no apparent impact on islet function. In summary, SGLT2 inhibition supported human islet function in vivo in the hyperglycemic milieu and potentially promoted alpha to beta cell transdifferentiation, most likely through an indirect mechanism.

17.
Rheumatol Ther ; 9(2): 649-661, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35184268

RESUMEN

INTRODUCTION: A phase IV clinical trial confirmed the safety and efficacy of repository corticotropin injection (RCI, Acthar® Gel) in patients with refractory rheumatoid arthritis (RA) that was nonresponsive to standard-of-care therapies. The objective of this post hoc analysis was to identify baseline demographics and clinical characteristics that may be predictors of response to RCI. METHODS: The phase IV trial was a two-part, randomized, placebo-controlled withdrawal study. Post hoc analysis was conducted with the open-label portion of the trial data, in which all 258 subjects received RCI (80 U) twice weekly for 12 weeks. Responders were subjects who achieved low disease activity (LDA) by a Disease Activity Score with 28-joint count and erythrocyte sedimentation rate (DAS28-ESR) of < 3.2 at week 12. Responders were compared with nonresponders by assessing the proportion of subjects in each group for demographics and clinical characteristics, including weight, disease duration, medical history including osteoarthritis and unrelated joint conditions, hemoglobin A1c, C-reactive protein, ESR, DAS28-ESR, Clinical Disease Activity Index (CDAI), depression, anxiety, tender joint count (TJC), and swollen joint count (SJC). Bivariate analysis followed by multiple logistic regression analysis were conducted to identify significant baseline predictors for the outcome of achieving LDA by week 12. RESULTS: Bivariate analysis showed that RCI responders had significantly lower baseline TJC (p = 0.0310), SJC (p = 0.0018), ESR (p = 0.0487), and CDAI (p = 0.0112) and shorter RA disease duration (p = 0.0446). Subjects were less likely to achieve LDA if they had osteoarthritis (p < 0.0001), other joint-related conditions unrelated to RA (p < 0.0001), anemia (p = 0.0132), depression (p = 0.0006), or prior or concomitant use of targeted-synthetic or biologic disease-modifying antirheumatic drugs (p < 0.0001). Multiple logistic regression analysis revealed that, of the above, only ongoing osteoarthritis (p = 0.0272) or other joint-related conditions (p = 0.0193) were significant negative predictors of RCI response. CONCLUSIONS: These results identify specific patient characteristics that may be considered predictors of positive or negative clinical response to RCI.

18.
Rheumatol Ther ; 9(2): 435-446, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34919213

RESUMEN

PURPOSE: Approximately 6% of patients with rheumatoid arthritis (RA) in the USA have refractory disease that is resistant to standard-of-care therapies. A recent phase IV clinical trial affirmed the safety and efficacy of repository corticotropin injection (RCI; Acthar® Gel) for refractory RA. This post hoc analysis of the clinical trial data assessed whether changes in clinical measures correlated with patient-reported outcome (PRO) improvements. METHODS: Data were assessed from the trial's open-label period when patients received RCI (80 U) twice weekly for 12 weeks. Clinical assessments included hemoglobin A1c, C-reactive protein, erythrocyte sedimentation rate (ESR), total joint count (TJC), swollen joint count (SJC), Disease Activity Score with 28 joint count and ESR (DAS28-ESR), and Clinical Disease Activity Index (CDAI). PROs included pain (Visual Analog Scale), fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue [FACIT-F]), disability (Health Assessment Questionnaire-Disability Index [HAQ-DI]), and activity impairment (Work Productivity and Activity Impairment [WPAI] questionnaire). Patients grouped by minimal clinically important difference (MCID) improvement vs no improvement in PROs were compared with clinical measures at week 12. Correlations were determined by multivariable linear regression analysis and standardized coefficient estimates. RESULTS: RCI responders, defined as patients with DAS28-ESR < 3.2 at week 12, reported significantly greater PRO improvements for pain, disability, fatigue, activity impairment, current work impairment, and overall work impairment than nonresponders. Patients with MCID improvements in all PROs showed significantly greater decreases in mean values for TJC, DAS28-ESR, and CDAI, whereas those with pain, fatigue, and disability improvements had significantly greater SJC and ESR reductions. Multivariable linear regression analysis determined that improvement from baseline in all PROs correlated with significant decreases in TJC, DAS28-ESR, and CDAI. ESR reduction significantly correlated with improvements in pain and disability, but not fatigue or WPAI. CONCLUSIONS: These results confirm that clinical responses to RCI were directly correlated with patient perception of improvement.

19.
ACS Med Chem Lett ; 13(4): 681-686, 2022 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-35450368

RESUMEN

Thiazolidinedione PPARγ agonists such as rosiglitazone and pioglitazone are effective antidiabetic drugs, but side effects have limited their use. It has been posited that their positive antidiabetic effects are mainly mediated by the inhibition of the CDK5-mediated Ser273 phosphorylation of PPARγ, whereas the side effects are linked to classical PPARγ agonism. Thus compounds that inhibit PPARγ Ser273 phosphorylation but lack classical PPARγ agonism have been sought as safer antidiabetic therapies. Herein we report the discovery by virtual screening of 10, which is a potent PPARγ binder and in vitro inhibitor of the CDK5-mediated phosphorylation of PPARγ Ser273 and displays negligible PPARγ agonism in a reporter gene assay. The pharmacokinetic properties of 10 are compatible with oral dosing, enabling preclinical in vivo testing, and a 7 day treatment demonstrated an improvement in insulin sensitivity in the ob/ob diabetic mouse model.

20.
Nat Commun ; 13(1): 6020, 2022 10 14.
Artículo en Inglés | MEDLINE | ID: mdl-36241646

RESUMEN

The fatty acid composition of phosphatidylethanolamine (PE) determines cellular metabolism, oxidative stress, and inflammation. However, our understanding of how cells regulate PE composition is limited. Here, we identify a genetic locus on mouse chromosome 11, containing two poorly characterized genes Tlcd1 and Tlcd2, that strongly influences PE composition. We generated Tlcd1/2 double-knockout (DKO) mice and found that they have reduced levels of hepatic monounsaturated fatty acid (MUFA)-containing PE species. Mechanistically, TLCD1/2 proteins act cell intrinsically to promote the incorporation of MUFAs into PEs. Furthermore, TLCD1/2 interact with the mitochondria in an evolutionarily conserved manner and regulate mitochondrial PE composition. Lastly, we demonstrate the biological relevance of our findings in dietary models of metabolic disease, where Tlcd1/2 DKO mice display attenuated development of non-alcoholic steatohepatitis compared to controls. Overall, we identify TLCD1/2 proteins as key regulators of cellular PE composition, with our findings having broad implications in understanding and treating disease.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Fosfatidiletanolaminas , Animales , Ácidos Grasos/metabolismo , Ácidos Grasos Monoinsaturados/metabolismo , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Fosfatidiletanolaminas/metabolismo
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