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1.
J Am Chem Soc ; 146(15): 10240-10245, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38578222

RESUMEN

Cellular compartments formed by biomolecular condensation are widespread features of cell biology. These organelle-like assemblies compartmentalize macromolecules dynamically within the crowded intracellular environment. However, the intermolecular interactions that produce condensed droplets may also create arrested states and potentially pathological assemblies such as fibers, aggregates, and gels through droplet maturation. Protein liquid-liquid phase separation is a metastable process, so maturation may be an intrinsic property of phase-separating proteins, where nucleation of different phases or states arises in supersaturated condensates. Here, we describe the formation of both phase-separated droplets and proteinaceous fibers driven by a de novo designed polypeptide. We characterize the formation of supramolecular fibers in vitro and in bacterial cells. We show that client proteins can be targeted to the fibers in cells using a droplet-forming construct. Finally, we explore the interplay between phase separation and fiber formation of the de novo polypeptide, showing that the droplets mature with a post-translational switch to largely ß conformations, analogous to models of pathological phase separation.


Asunto(s)
Fenómenos Bioquímicos , Proteínas , Humanos , Proteínas/química , Péptidos/metabolismo , Procesamiento Proteico-Postraduccional , Conformación Molecular
3.
J Vinyl Addit Technol ; 29(4): 795-812, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37546292

RESUMEN

Although processing via external stimuli is a promising technique to tune the structure and properties of polymeric materials, the impact of magnetic fields on phase transitions in thermoresponsive polymer solutions is not well-understood. As nanoparticle (NP) addition is also known to impact these thermodynamic and optical properties, synergistic effects from combining magnetic fields with NP incorporation provide a novel route for tuning material properties. Here, the thermodynamic, optical, and rheological properties of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions are examined in the presence of hydrophilic silica NPs and magnetic fields, individually and jointly, via Fourier-transform infrared spectroscopy (FTIR), magneto-turbidimetry, differential scanning calorimetry (DSC), and magneto-rheology. While NPs and magnetic fields both reduce the phase separation energy barrier and lower optical transition temperatures by altering hydrogen bonding (H-bonding), infrared spectra demonstrate that the mechanism by which these changes occur is distinct. Magnetic fields primarily alter solvent polarization while NPs provide PNIPAM-NP H-bonding sites. Combining NP addition with field application uniquely alters the solution environment and results in field-dependent rheological behavior that is unseen in polymer-only solutions. These investigations provide fundamental understanding on the interplay of magnetic fields and NP addition on PNIPAM thermoresponsivity which can be harnessed for increasingly complex stimuli-responsive materials.

4.
Wound Repair Regen ; 30(1): 64-81, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34618990

RESUMEN

Negative pressure wound therapy (NPWT) is used clinically to promote tissue formation and wound closure. In this study, a porcine wound model was used to further investigate the mechanisms as to how NPWT modulates wound healing via utilization of a form of NPWT called the vacuum-assisted closure. To observe the effect of NPWT more accurately, non-NPWT control wounds containing GranuFoam™ dressings, without vacuum exposure, were utilized. In situ histological analysis revealed that NPWT enhanced plasma protein adsorption throughout the GranuFoam™, resulting in increased cellular colonization and tissue ingrowth. Gram staining revealed that NPWT decreased bacterial dissemination to adjacent tissue with greater bacterial localization within the GranuFoam™. Genomic analysis demonstrated the significant changes in gene expression across a number of genes between wounds treated with non-NPWT and NPWT when compared against baseline tissue. However, minimal differences were noted between non-NPWT and NPWT wounds, including no significant differences in expression of collagen, angiogenic, or key inflammatory genes. Similarly, significant increases in immune cell populations were observed from day 0 to day 9 for both non-NPWT and NPWT wounds, though no differences were noted between non-NPWT and NPWT wounds. Furthermore, histological analysis demonstrated the presence of a foreign body response (FBR), with giant cell formation and encapsulation of GranuFoam™ particles. The unique in situ histological evaluation and genomic comparison of non-NPWT and NPWT wounds in this pilot study provided a never-before-shown perspective, offering novel insights into the physiological processes of NPWT and the potential role of a FBR in NPWT clinical outcomes.


Asunto(s)
Terapia de Presión Negativa para Heridas , Cicatrización de Heridas , Animales , Vendajes , Proyectos Piloto , Porcinos
5.
Am J Physiol Renal Physiol ; 320(3): F492-F504, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33491562

RESUMEN

Although macula densa (MD) cells are chief regulatory cells in the nephron with unique microanatomical features, they have been difficult to study in full detail due to their inaccessibility and limitations in earlier microscopy techniques. The present study used a new mouse model with a comprehensive imaging approach to visualize so far unexplored microanatomical features of MD cells, their regulation, and functional relevance. MD-GFP mice with conditional and partial induction of green fluorescent protein (GFP) expression, which specifically and intensely illuminated only single MD cells, were used with fluorescence microscopy of fixed tissue and live MD cells in vitro and in vivo with complementary electron microscopy of the rat, rabbit, and human kidney. An elaborate network of major and minor cell processes, here named maculapodia, were found at the cell base, projecting toward other MD cells and the glomerular vascular pole. The extent of maculapodia showed upregulation by low dietary salt intake and the female sex. Time-lapse imaging of maculapodia revealed highly dynamic features including rapid outgrowth and an extensive vesicular transport system. Electron microscopy of rat, rabbit, and human kidneys and three-dimensional volume reconstruction in optically cleared whole-mount MD-GFP mouse kidneys further confirmed the presence and projections of maculapodia into the extraglomerular mesangium and afferent and efferent arterioles. The newly identified dynamic and secretory features of MD cells suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD cells and between MD and other target cells.NEW & NOTEWORTHY This study illuminated a physiologically regulated dense network of basal cell major and minor processes (maculapodia) in macula densa (MD) cells. The newly identified dynamic and secretory features of these microanatomical structures suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD and other target cells. Detailed characterization of the function and molecular details of MD cell intercellular communications and their role in physiology and disease warrant further studies.


Asunto(s)
Mesangio Glomerular/ultraestructura , Aparato Yuxtaglomerular/ultraestructura , Glomérulos Renales/ultraestructura , Túbulos Renales/ultraestructura , Animales , Comunicación Celular/fisiología , Células Epiteliales/citología , Células Epiteliales/ultraestructura , Mesangio Glomerular/citología , Glomérulos Renales/citología , Túbulos Renales/citología , Ratones , Conejos , Ratas
6.
Mar Drugs ; 19(2)2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33670308

RESUMEN

To tackle the growing problem of antibiotic resistance, it is essential to identify new bioactive compounds that are effective against resistant microbes and safe to use. Natural products and their derivatives are, and will continue to be, an important source of these molecules. Sea sponges harbour a diverse microbiome that co-exists with the sponge, and these bacterial communities produce a rich array of bioactive metabolites for protection and resource competition. For these reasons, the sponge microbiota constitutes a potential source of clinically relevant natural products. To date, efforts in bioprospecting for these compounds have focused predominantly on sponge specimens isolated from shallow water, with much still to be learned about samples from the deep sea. Here we report the isolation of a new Micromonospora strain, designated 28ISP2-46T, recovered from the microbiome of a mid-Atlantic deep-sea sponge. Whole-genome sequencing reveals the capacity of this bacterium to produce a diverse array of natural products, including kosinostatin and isoquinocycline B, which exhibit both antibiotic and antitumour properties. Both compounds were isolated from 28ISP2-46T fermentation broths and were found to be effective against a plethora of multidrug-resistant clinical isolates. This study suggests that the marine production of isoquinocyclines may be more widespread than previously supposed and demonstrates the value of targeting the deep-sea sponge microbiome as a source of novel microbial life with exploitable biosynthetic potential.


Asunto(s)
Antibacterianos/aislamiento & purificación , Microbiota , Micromonospora/aislamiento & purificación , Poríferos/microbiología , Animales , Antibacterianos/farmacología , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Océano Atlántico , Productos Biológicos/aislamiento & purificación , Productos Biológicos/farmacología , Secuenciación Completa del Genoma
7.
J Neurol Neurosurg Psychiatry ; 91(4): 359-365, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32034113

RESUMEN

INTRODUCTION: Traumatic brain injury (TBI) is the most common cause of death on the modern battlefield. In recent conflicts in Iraq and Afghanistan, the US typically deployed neurosurgeons to medical treatment facilities (MTFs), while the UK did not. Our aim was to compare the incidence, TBI and treatment in US and UK-led military MTF to ascertain if differences in deployed trauma systems affected outcomes. METHODS: The US and UK Combat Trauma Registries were scrutinised for patients with HI at deployed MTFs between March 2003 and October 2011. Registry datasets were adapted to stratify TBI using the Mayo Classification System for Traumatic Brain Injury Severity. An adjusted multiple logistic regression model was performed using fatality as the binomial dependent variable and treatment in a US-MTF or UK-MTF, surgical decompression, US military casualty and surgery performed by a neurosurgeon as independent variables. RESULTS: 15 031 patients arrived alive at military MTF after TBI. Presence of a neurosurgeon was associated with increased odds of survival in casualties with moderate or severe TBI (p<0.0001, OR 2.71, 95% CI 2.34 to 4.73). High injury severity (Injury Severity Scores 25-75) was significantly associated with a lower survival (OR 4×104, 95% CI 1.61×104 to 110.6×104, p<0.001); however, having a neurosurgeon present still remained significantly positively associated with survival (OR 3.25, 95% CI 2.71 to 3.91, p<0.001). CONCLUSIONS: Presence of neurosurgeons increased the likelihood of survival after TBI. We therefore recommend that the UK should deploy neurosurgeons to forward military MTF whenever possible in line with their US counterparts.


Asunto(s)
Lesiones Traumáticas del Encéfalo/mortalidad , Personal Militar , Procedimientos Neuroquirúrgicos , Adulto , Campaña Afgana 2001- , Lesiones Traumáticas del Encéfalo/cirugía , Femenino , Humanos , Puntaje de Gravedad del Traumatismo , Guerra de Irak 2003-2011 , Masculino , Neurocirujanos , Estudios Retrospectivos , Tasa de Supervivencia , Reino Unido , Estados Unidos
8.
Br J Cancer ; 121(1): 65-75, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31123345

RESUMEN

BACKGROUND: S100 proteins have been implicated in various aspects of cancer, including epithelial-mesenchymal transitions (EMT), invasion and metastasis, and also in inflammatory disorders. Here we examined the impact of individual members of this family on the invasion of pancreatic ductal adenocarcinoma (PDAC) cells, and their regulation by EMT and inflammation. METHODS: Invasion of PDAC cells was analysed in zebrafish embryo xenografts and in transwell invasion assays. Expression and regulation of S100 proteins was studied in vitro by immunoblotting, quantitative PCR and immunofluorescence, and in pancreatic lesions by immunohistochemistry. RESULTS: Whereas the expression of most S100 proteins is characteristic for epithelial PDAC cell lines, S100A4 and S100A6 are strongly expressed in mesenchymal cells and upregulated by ZEB1. S100A4/A6 and epithelial protein S100A14 respectively promote and represses cell invasion. IL-6/11-STAT3 pathway stimulates expression of most S100 proteins. ZEB1 synergises with IL-6/11-STAT3 to upregulate S100A4/A6, but nullifies the effect of inflammation on S100A14 expression. CONCLUSION: EMT/ZEB1 and IL-6/11-STAT3 signalling act independently and congregate to establish the expression pattern of S100 proteins, which drives invasion. Although ZEB1 regulates expression of S100 family members, these effects are masked by IL-6/11-STAT3 signalling, and S100 proteins cannot be considered as bona fide EMT markers in PDAC.


Asunto(s)
Interleucina-11/fisiología , Interleucina-6/fisiología , Neoplasias Pancreáticas/patología , Proteínas S100/genética , Factor de Transcripción STAT3/fisiología , Homeobox 1 de Unión a la E-Box con Dedos de Zinc/fisiología , Animales , Línea Celular Tumoral , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , Humanos , Invasividad Neoplásica , Transducción de Señal/fisiología , Pez Cebra
9.
Am J Physiol Renal Physiol ; 315(5): F1370-F1384, 2018 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-29923763

RESUMEN

To investigate human glomerular structure under conditions of physiological perfusion, we have analyzed fresh and perfusion-fixed normal human glomeruli at physiological hydrostatic and oncotic pressures using serial resin section reconstruction, confocal, multiphoton, and electron microscope imaging. Afferent and efferent arterioles (21.5 ± 1.2 µm and 15.9 ± 1.2 µm diameter), recognized from vascular origins, lead into previously undescribed wider regions (43.2 ± 2.8 µm and 38.4 ± 4.9 µm diameter) we have termed vascular chambers (VCs) embedded in the mesangium of the vascular pole. Afferent VC (AVC) volume was 1.6-fold greater than efferent VC (EVC) volume. From the AVC, long nonbranching high-capacity conduit vessels ( n = 7) (Con; 15.9 ± 0.7 µm diameter) led to the glomerular edge, where branching was more frequent. Conduit vessels have fewer podocytes than filtration capillaries. VCs were confirmed in fixed and unfixed specimens with a layer of banded collagen identified in AVC walls by multiphoton and electron microscopy. Thirteen highly branched efferent first-order vessels (E1; 9.9 ± 0.4 µm diameter) converge on the EVC, draining into the efferent arteriole (15.9 ± 1.2 µm diameter). Banded collagen was scarce around EVCs. This previously undescribed branching topology does not conform to the branching of minimum energy expenditure (Murray's law), suggesting that even distribution of pressure/flow to the filtration capillaries is more important than maintaining the minimum work required for blood flow. We propose that AVCs act as plenum manifolds possibly aided by vortical flow in distributing and balancing blood flow/pressure to conduit vessels supplying glomerular lobules. These major adaptations to glomerular capillary structure could regulate hemodynamic pressure and flow in human glomerular capillaries.


Asunto(s)
Hemodinámica , Glomérulos Renales/irrigación sanguínea , Microcirculación , Microvasos/fisiología , Circulación Renal , Humanos , Presión Hidrostática , Microscopía Confocal , Microscopía Electrónica de Transmisión , Microscopía de Fluorescencia por Excitación Multifotónica , Microvasos/ultraestructura , Modelos Biológicos , Podocitos/fisiología , Fijación del Tejido
10.
Kidney Int ; 93(5): 1086-1097, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29433915

RESUMEN

Increased urinary albumin excretion is a key feature of glomerular disease but has limitations as a measure of glomerular permeability. Here we describe a novel assay to measure the apparent albumin permeability of single capillaries in glomeruli, isolated from perfused kidneys cleared of red blood cells. The rate of decline of the albumin concentration within the capillary lumen was quantified using confocal microscopy and used to calculate apparent permeability. The assay was extensively validated and provided robust, reproducible estimates of glomerular albumin permeability. These values were comparable with previous in vivo data, showing this assay could be applied to human as well as rodent glomeruli. To confirm this, we showed that targeted endothelial glycocalyx disruption resulted in increased glomerular albumin permeability in mice. Furthermore, incubation with plasma from patients with post-transplant recurrence of nephrotic syndrome increased albumin permeability in rat glomeruli compared to remission plasma. Finally, in glomeruli isolated from rats with early diabetes there was a significant increase in albumin permeability and loss of endothelial glycocalyx, both of which were ameliorated by angiopoietin-1. Thus, a glomerular permeability assay, producing physiologically relevant values with sufficient sensitivity to measure changes in glomerular permeability and independent of tubular function, was developed and validated. This assay significantly advances the ability to study biology and disease in rodent and human glomeruli.


Asunto(s)
Bioensayo/métodos , Capilares/metabolismo , Permeabilidad Capilar , Glomérulos Renales/irrigación sanguínea , Albúmina Sérica/metabolismo , Albuminuria/metabolismo , Albuminuria/fisiopatología , Angiopoyetina 1/farmacología , Animales , Capilares/efectos de los fármacos , Capilares/fisiopatología , Permeabilidad Capilar/efectos de los fármacos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/fisiopatología , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/fisiopatología , Femenino , Glicocálix/metabolismo , Humanos , Técnicas In Vitro , Cinética , Masculino , Ratones Endogámicos C57BL , Microscopía Confocal , Síndrome Nefrótico/sangre , Síndrome Nefrótico/fisiopatología , Ratas Sprague-Dawley , Reproducibilidad de los Resultados
11.
J Physiol ; 595(19): 6281-6298, 2017 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-28574576

RESUMEN

KEY POINTS: Progressive depletion of all vascular endothelial growth factor A (VEGF-A) splice isoforms from the kidney results in proteinuria and increased glomerular water permeability, which are both rescued by over-expression of VEGF-A165 b only. VEGF-A165 b rescues the increase in glomerular basement membrane and podocyte slit width, as well as the decrease in sub-podocyte space coverage, produced by VEGF-A depletion. VEGF-A165 b restores the expression of platelet endothelial cell adhesion molecule in glomerular endothelial cells and glomerular capillary circumference. VEGF-A165 b has opposite effects to VEGF-A165 on the expression of genes involved in endothelial cell migration and proliferation. ABSTRACT: Chronic kidney disease is strongly associated with a decrease in the expression of vascular endothelial growth factor A (VEGF-A). However, little is known about the contribution of VEGF-A splice isoforms to kidney physiology and pathology. Previous studies suggest that the splice isoform VEGF-A165 b (resulting from alternative usage of a 3' splice site in the terminal exon) is protective for kidney function. In the present study, we show, in a quad-transgenic model, that over-expression of VEGF-A165 b alone is sufficient to rescue the increase in proteinuria, as well as glomerular water permeability, in the context of progressive depletion of all VEGF-A isoforms from the podocytes. Ultrastructural studies show that the glomerular basement membrane is thickened, podocyte slit width is increased and sub-podocyte space coverage is reduced when VEGF-A is depleted, all of which are rescued in VEGF-A165 b over-expressors. VEGF-A165 b restores the expression of platelet endothelial cell adhesion molecule-1 in glomerular endothelial cells and glomerular capillary circumference. Mechanistically, it increases VEGF receptor 2 expression both in vivo and in vitro and down-regulates genes involved in migration and proliferation of endothelial cells, otherwise up-regulated by the canonical isoform VEGF-A165 . The results of the present study indicate that manipulation of VEGF-A splice isoforms could be a novel therapeutic avenue in chronic glomerular disease.


Asunto(s)
Riñón/metabolismo , Proteinuria/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Animales , Línea Celular , Humanos , Riñón/patología , Ratones , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/genética , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Podocitos/metabolismo , Podocitos/ultraestructura , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteinuria/genética , Proteinuria/patología , Receptores de Factores de Crecimiento Endotelial Vascular/genética , Receptores de Factores de Crecimiento Endotelial Vascular/metabolismo , Proteína Transformadora 1 que Contiene Dominios de Homología 2 de Src/genética , Proteína Transformadora 1 que Contiene Dominios de Homología 2 de Src/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética
12.
J Physiol ; 595(15): 5015-5035, 2017 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-28524373

RESUMEN

KEY POINTS: We have developed novel techniques for paired, direct, real-time in vivo quantification of endothelial glycocalyx structure and associated microvessel permeability. Commonly used imaging and analysis techniques yield measurements of endothelial glycocalyx depth that vary by over an order of magnitude within the same vessel. The anatomical distance between maximal glycocalyx label and maximal endothelial cell plasma membrane label provides the most sensitive and reliable measure of endothelial glycocalyx depth. Sialic acid residues of the endothelial glycocalyx regulate glycocalyx structure and microvessel permeability to both water and albumin. ABSTRACT: The endothelial glycocalyx forms a continuous coat over the luminal surface of all vessels, and regulates multiple vascular functions. The contribution of individual components of the endothelial glycocalyx to one critical vascular function, microvascular permeability, remains unclear. We developed novel, real-time, paired methodologies to study the contribution of sialic acids within the endothelial glycocalyx to the structural and functional permeability properties of the same microvessel in vivo. Single perfused rat mesenteric microvessels were perfused with fluorescent endothelial cell membrane and glycocalyx labels, and imaged with confocal microscopy. A broad range of glycocalyx depth measurements (0.17-3.02 µm) were obtained with different labels, imaging techniques and analysis methods. The distance between peak cell membrane and peak glycocalyx label provided the most reliable measure of endothelial glycocalyx anatomy, correlating with paired, numerically smaller values of endothelial glycocalyx depth (0.078 ± 0.016 µm) from electron micrographs of the same portion of the same vessel. Disruption of sialic acid residues within the endothelial glycocalyx using neuraminidase perfusion decreased endothelial glycocalyx depth and increased apparent solute permeability to albumin in the same vessels in a time-dependent manner, with changes in all three true vessel wall permeability coefficients (hydraulic conductivity, reflection coefficient and diffusive solute permeability). These novel technologies expand the range of techniques that permit direct studies of the structure of the endothelial glycocalyx and dependent microvascular functions in vivo, and demonstrate that sialic acid residues within the endothelial glycocalyx are critical regulators of microvascular permeability to both water and albumin.


Asunto(s)
Permeabilidad Capilar , Células Endoteliales/metabolismo , Glicocálix/metabolismo , Microvasos/metabolismo , Ácidos Siálicos/metabolismo , Albúminas/metabolismo , Animales , Células Endoteliales/ultraestructura , Glicocálix/ultraestructura , Masculino , Mesenterio/irrigación sanguínea , Microscopía Electrónica de Transmisión , Microvasos/ultraestructura , Ratas , Ratas Sprague-Dawley , Agua/metabolismo
13.
Am J Physiol Renal Physiol ; 313(1): F126-F134, 2017 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-28356291

RESUMEN

Biological soft tissues are viscoelastic because they display time-independent pseudoelasticity and time-dependent viscosity. However, there is evidence that the bladder may also display plasticity, defined as an increase in strain that is unrecoverable unless work is done by the muscle. In the present study, an electronic lever was used to induce controlled changes in stress and strain to determine whether rabbit detrusor smooth muscle (rDSM) is best described as viscoelastic or viscoelastic plastic. Using sequential ramp loading and unloading cycles, stress-strain and stiffness-stress analyses revealed that rDSM displayed reversible viscoelasticity, and that the viscous component was responsible for establishing a high stiffness at low stresses that increased only modestly with increasing stress compared with the large increase produced when the viscosity was absent and only pseudoelasticity governed tissue behavior. The study also revealed that rDSM underwent softening correlating with plastic deformation and creep that was reversed slowly when tissues were incubated in a Ca2+-containing solution. Together, the data support a model of DSM as a viscoelastic-plastic material, with the plasticity resulting from motor protein activation. This model explains the mechanism of intrinsic bladder compliance as "slipping" cross bridges, predicts that wall tension is dependent not only on vesicle pressure and radius but also on actomyosin cross-bridge activity, and identifies a novel molecular target for compliance regulation, both physiologically and therapeutically.


Asunto(s)
Actomiosina/metabolismo , Contracción Muscular , Músculo Liso/enzimología , Vejiga Urinaria/enzimología , Quinasas Asociadas a rho/metabolismo , Animales , Fenómenos Biomecánicos , Adaptabilidad , Masculino , Modelos Biológicos , Conejos , Transducción de Señal , Estrés Mecánico , Factores de Tiempo , Viscosidad
14.
Langenbecks Arch Surg ; 402(5): 811-819, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28434059

RESUMEN

PURPOSE: The aim of this study was to compare the prognostic value of established scoring systems with early warning scores in a large cohort of patients with acute pancreatitis. METHODS: In patients presenting with acute pancreatitis, age, sex, American Society of Anaesthesiologists (ASA) grade, Modified Glasgow Score, Ranson criteria, APACHE II scores and early warning score (EWS) were recorded for the first 72 h following admission. These variables were compared between survivors and non-survivors, between patients with mild/moderate and severe pancreatitis (based on the 2012 Atlanta Classification) and between patients with a favourable or adverse outcome. RESULTS: A total of 629 patients were identified. EWS was the best predictor of adverse outcome amongst all of the assessed variables (area under curve (AUC) values 0.81, 0.84 and 0.83 for days 1, 2 and 3, respectively) and was the most accurate predictor of mortality on both days 2 and 3 (AUC values of 0.88 and 0.89, respectively). Multivariable analysis revealed that an EWS ≥2 was independently associated with severity of pancreatitis, adverse outcome and mortality. CONCLUSION: This study confirms the usefulness of EWS in predicting the outcome of acute pancreatitis. It should become the mainstay of risk stratification in patients with acute pancreatitis.


Asunto(s)
Pancreatitis/mortalidad , Pancreatitis/cirugía , Enfermedad Aguda , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
16.
Med Educ ; 49(9): 928-32, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26296409

RESUMEN

CONTEXT: Student evaluations of teaching (SETs) inform faculty promotion decisions and course improvement, a process that is predicated on the assumption that students complete the evaluations with diligence. Anecdotal evidence suggests that this may not be so. OBJECTIVES: We sought to determine the degree to which medical students complete SETs deliberately in a classroom-style, multi-instructor course. METHODS: We inserted one fictitious lecturer into each of two pre-clinical courses. Students were required to submit their anonymous ratings of all lecturers, including the fictitious one, within 2 weeks after the course using a 5-point Likert scale, but could choose not to evaluate a lecturer. The following year, we repeated this but included a portrait of the fictitious lecturer. The number of actual lecturers in each course ranged from 23 to 52. RESULTS: Response rates were 99% and 94%, respectively, in the 2 years of the study. Without a portrait, 66% (183 of 277) of students evaluated the fictitious lecturer, but fewer students (49%, 140 of 285) did so with a portrait (chi-squared test, p < 0.0001). CONCLUSIONS: These findings suggest that many medical students complete SETs mindlessly, even when a photograph is included, without careful consideration of whom they are evaluating and much less of how that faculty member performed. This hampers programme quality improvement and may harm the academic advancement of faculty members. We present a framework that suggests a fundamentally different approach to SET that involves students prospectively and proactively.


Asunto(s)
Docentes Médicos/normas , Estudiantes de Medicina/psicología , Enseñanza/métodos , Estudios de Evaluación como Asunto , Humanos , Competencia Profesional , Enseñanza/normas
17.
J Am Soc Nephrol ; 25(1): 129-41, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24071005

RESUMEN

Parietal podocytes are fully differentiated podocytes lining Bowman's capsule where normally only parietal epithelial cells (PECs) are found. Parietal podocytes form throughout life and are regularly observed in human biopsies, particularly in atubular glomeruli of diseased kidneys; however, the origin of parietal podocytes is unresolved. To assess the capacity of PECs to transdifferentiate into parietal podocytes, we developed and characterized a novel method for creating atubular glomeruli by electrocoagulation of the renal cortex in mice. Electrocoagulation produced multiple atubular glomeruli containing PECs as well as parietal podocytes that projected from the vascular pole and lined Bowman's capsule. Notably, induction of cell death was evident in some PECs. In contrast, Bowman's capsules of control animals and normal glomeruli of electrocoagulated kidneys rarely contained podocytes. PECs and podocytes were traced by inducible and irreversible genetic tagging using triple transgenic mice (PEC- or Pod-rtTA/LC1/R26R). Examination of serial cryosections indicated that visceral podocytes migrated onto Bowman's capsule via the vascular stalk; direct transdifferentiation from PECs to podocytes was not observed. Similar results were obtained in a unilateral ureter obstruction model and in human diseased kidney biopsies, in which overlap of PEC- or podocyte-specific antibody staining indicative of gradual differentiation did not occur. These results suggest that induction of atubular glomeruli leads to ablation of PECs and subsequent migration of visceral podocytes onto Bowman's capsule, rather than transdifferentiation from PECs to parietal podocytes.


Asunto(s)
Glomérulos Renales/citología , Podocitos/citología , Animales , Cápsula Glomerular/citología , Linaje de la Célula , Movimiento Celular , Transdiferenciación Celular , Modelos Animales de Enfermedad , Electrocoagulación , Células Epiteliales/citología , Femenino , Humanos , Glomérulos Renales/cirugía , Masculino , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Biológicos , Podocitos/metabolismo , Obstrucción Ureteral/patología
18.
J Surg Oncol ; 110(7): 828-38, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25043295

RESUMEN

The serine/threonine kinase Nek2 (NIMA-related kinase 2) regulates centrosome separation and mitotic progression, with overexpression causing induction of aneuploidy in vitro. Overexpression may also enable tumour progression through effects upon Akt signalling, cell adhesion markers and the Wnt pathway. The objective of this study was to examine Nek2 protein expression in colorectal cancer (CRC). Nek2 protein expression was examined in a panel of CRC cell lines using Western blotting and immunofluorescence microscopy. Nek2 and beta-catenin expression were examined by immunohistochemistry in a series of resected CRC, as well as their matched lymph node and liver metastases, and correlated with clinicopathological characteristics. Nek2 protein expression in all CRC lines examined was higher than in the immortalised colonocyte line HCEC. Nek2 overexpression was present in 86.4% of resected CRC and was significantly associated with advancing AJCC tumour stage and shortened cancer-specific survival. Elevated Nek2 expression was maintained within all matched metastases from overexpressing primary tumours. Nek2 overexpression was significantly associated with lower tumour membranous beta-catenin expression and higher cytoplasmic and nuclear beta-catenin accumulation. These data support a role for Nek2 in CRC progression and confirm potential for Nek2 inhibition as a therapeutic avenue in CRC.


Asunto(s)
Membrana Celular/metabolismo , Núcleo Celular/metabolismo , Neoplasias Colorrectales/metabolismo , Citoplasma/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , beta Catenina/metabolismo , Adenocarcinoma Mucinoso/metabolismo , Adenocarcinoma Mucinoso/mortalidad , Adenocarcinoma Mucinoso/secundario , Anciano , Western Blotting , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Femenino , Estudios de Seguimiento , Humanos , Técnicas para Inmunoenzimas , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/secundario , Metástasis Linfática , Masculino , Microscopía Fluorescente , Quinasas Relacionadas con NIMA , Clasificación del Tumor , Estadificación de Neoplasias , Pronóstico , Tasa de Supervivencia , Células Tumorales Cultivadas
19.
Healthcare (Basel) ; 12(6)2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38540640

RESUMEN

Wellness-centric proactive healthcare is increasingly sought after, with individuals frequently embracing complementary modalities to achieve this goal. In this six-month study, healthy adult participants (n = 25) received specific therapies, including whole-body cryotherapy, infrared sauna, and photobiomodulation, along with guidance on physical activity, diet, and alcohol intake. Serum biomarkers were measured for all participants, while a subset also received biometric assessments for body composition (n = 10) and heart rate variability (n = 7). Over the course of the study (mean (SD) follow-up days = 174 (130)), participants exhibited significant improvements in health. LDL cholesterol (-9.77 (15.43) md/dL) and hsCRP (-1.75 (2.66) mg/L) decreased significantly (p < 0.05). HbA1c increased slightly (p < 0.05), but the effect size was small (0.12 (0.13)%). The body composition subset lost overall body weight (-3.29 (3.75) kg), primarily body fat, while preserving lean muscle mass (p < 0.05). Heart rate variability increased for those with existing cardiovascular risk factors (p < 0.05). In conclusion, participation in the multimodal Healthspan protocol is associated with substantial improvements in health-related biomarkers and biometrics.

20.
Mil Med ; 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38877894

RESUMEN

Management of the patient with moderate to severe brain injury in any environment can be time consuming and resource intensive. These challenges are magnified while forward deployed in austere or hostile environments. This Joint Trauma System Clinical Practice Guideline provides recommendations for the treatment and medical management of casualties with moderate to severe head injuries in an environment where personnel, resources, and follow-on care are limited. These guidelines have been developed by acknowledging commonly recognized recommendations for neurosurgical and neuro-critical care patients and augmenting those evaluations and interventions based on the experience of neurosurgeons, trauma surgeons, and intensivists who have delivered care during recent coalition conflicts.

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