Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Más filtros

Banco de datos
Tipo del documento
Publication year range
1.
Proc Natl Acad Sci U S A ; 114(12): 3085-3090, 2017 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-28265087

RESUMEN

Active-learning pedagogies have been repeatedly demonstrated to produce superior learning gains with large effect sizes compared with lecture-based pedagogies. Shifting large numbers of college science, technology, engineering, and mathematics (STEM) faculty to include any active learning in their teaching may retain and more effectively educate far more students than having a few faculty completely transform their teaching, but the extent to which STEM faculty are changing their teaching methods is unclear. Here, we describe the development and application of the machine-learning-derived algorithm Decibel Analysis for Research in Teaching (DART), which can analyze thousands of hours of STEM course audio recordings quickly, with minimal costs, and without need for human observers. DART analyzes the volume and variance of classroom recordings to predict the quantity of time spent on single voice (e.g., lecture), multiple voice (e.g., pair discussion), and no voice (e.g., clicker question thinking) activities. Applying DART to 1,486 recordings of class sessions from 67 courses, a total of 1,720 h of audio, revealed varied patterns of lecture (single voice) and nonlecture activity (multiple and no voice) use. We also found that there was significantly more use of multiple and no voice strategies in courses for STEM majors compared with courses for non-STEM majors, indicating that DART can be used to compare teaching strategies in different types of courses. Therefore, DART has the potential to systematically inventory the presence of active learning with ∼90% accuracy across thousands of courses in diverse settings with minimal effort.


Asunto(s)
Aprendizaje Basado en Problemas/normas , Ciencia/educación , Enseñanza/normas , Humanos , Sonido , Estudiantes , Tecnología , Universidades/normas
2.
CBE Life Sci Educ ; 18(3): ar47, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31469624

RESUMEN

Instructor Talk-noncontent language used by instructors in classrooms-is a recently defined and promising variable for better understanding classroom dynamics. Having previously characterized the Instructor Talk framework within the context of a single course, we present here our results surrounding the applicability of the Instructor Talk framework to noncontent language used by instructors in novel course contexts. We analyzed Instructor Talk in eight additional biology courses in their entirety and in 61 biology courses using an emergent sampling strategy. We observed widespread use of Instructor Talk with variation in the amount and category type used. The vast majority of Instructor Talk could be characterized using the originally published Instructor Talk framework, suggesting the robustness of this framework. Additionally, a new form of Instructor Talk-Negatively Phrased Instructor Talk, language that may discourage students or distract from the learning process-was detected in these novel course contexts. Finally, the emergent sampling strategy described here may allow investigation of Instructor Talk in even larger numbers of courses across institutions and disciplines. Given its widespread use, potential influence on students in learning environments, and ability to be sampled, Instructor Talk may be a key variable to consider in future research on teaching and learning in higher education.


Asunto(s)
Biología/educación , Docentes , Enseñanza , Curriculum , Recolección de Datos , Humanos , Aprendizaje , Estudiantes
3.
CBE Life Sci Educ ; 17(1)2018.
Artículo en Inglés | MEDLINE | ID: mdl-29326102

RESUMEN

Many efforts to improve science teaching in higher education focus on a few faculty members at an institution at a time, with limited published evidence on attempts to engage faculty across entire departments. We created a long-term, department-wide collaborative professional development program, Biology Faculty Explorations in Scientific Teaching (Biology FEST). Across 3 years of Biology FEST, 89% of the department's faculty completed a weeklong scientific teaching institute, and 83% of eligible instructors participated in additional semester-long follow-up programs. A semester after institute completion, the majority of Biology FEST alumni reported adding active learning to their courses. These instructor self-reports were corroborated by audio analysis of classroom noise and surveys of students in biology courses on the frequency of active-learning techniques used in classes taught by Biology FEST alumni and nonalumni. Three years after Biology FEST launched, faculty participants overwhelmingly reported that their teaching was positively affected. Unexpectedly, most respondents also believed that they had improved relationships with departmental colleagues and felt a greater sense of belonging to the department. Overall, our results indicate that biology department-wide collaborative efforts to develop scientific teaching skills can indeed attract large numbers of faculty, spark widespread change in teaching practices, and improve departmental relations.


Asunto(s)
Biología/educación , Desarrollo de Programa , Enseñanza , Docentes , Objetivos , Humanos , Motivación , Aprendizaje Basado en Problemas , Estudiantes , Encuestas y Cuestionarios
4.
Am J Vet Res ; 66(6): 984-90, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16008220

RESUMEN

OBJECTIVE: To investigate the activities of hyaluronidases in equine sera and synovial fluid samples and sera from fetal and adult bovids and evaluate the extent to which the degradation of hyaluronan is influenced by chondrocytes. SAMPLE POPULATION: Commercial and noncommercial samples of equine (n = 6) and bovine (6) sera and 16 synovial fluid samples from horses. PROCEDURE: Hyaluronidase activities in sera and synovial fluid samples were assessed via enzyme zymography (performed at pH 4, 5, 6, or 7). Chondrocytes were isolated from equine cartilage and cultured with or without hyaluronan (1 mg/mL); the degradation of hyaluronan was assessed via agarose gel electrophoresis. RESULTS: [corrected] Hyaluronidase activity was detected in equine sera and synovial fluid samples at pH 4, but not at pH 7, and in bovine sera at both pH values. In all samples at pH 4, a major band of activity (molecular weight, approx 60 kd) and some additional higher molecular weight bands were detected; high- and low-molecular-weight activities were detected in bovine sera at pH 7 Hyaluronan in tissue culture medium with or without fetal calf serum was degraded in the presence, but not the absence, of equine chondrocytes. CONCLUSIONS AND CLINICAL RELEVANCE: Hyaluronidase activity was detected in equine sera and synovial fluid at pH 4 and in bovine sera at pH 4 and 7. Primary chondrocytes in monolayer culture can degrade exogenous hyaluronan. Modulating native hyaluronidase activity may offer a new approach to improve the quantity and quality of hyaluronan in articular joints.


Asunto(s)
Bovinos/metabolismo , Caballos/metabolismo , Hialuronoglucosaminidasa/metabolismo , Líquido Sinovial/enzimología , Animales , Bovinos/sangre , Condrocitos/enzimología , Electroforesis en Gel de Agar/métodos , Electroforesis en Gel de Agar/veterinaria , Caballos/sangre , Ácido Hialurónico/metabolismo , Concentración de Iones de Hidrógeno
5.
Am J Vet Res ; 63(2): 204-10, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11843119

RESUMEN

OBJECTIVE: To determine whether adenosine influences the in vitro release of nitric oxide (NO) from differentiated primary equine articular chondrocytes. SAMPLE POPULATION: Articular cartilage harvested from the metacarpophalangeal and metatarsophalangeal joints of 11 horses (3 to 11 years old) without history or clinical signs of joint disease. PROCEDURE: Chondrocytes were isolated, plated at a high density (10(5) cells/well), and treated with adenosine, the adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA), bradykinin, or other agents that modify secondary messenger pathways alone or in combination with bacterial lipopolysaccharide (LPS) or recombinant human interleukin-1alpha (rhIL-1alpha). Nitric oxide release was measured indirectly by use of the Griess reaction and was expressed as micromol of nitrite in the supernatant/microg of protein in the cell layer. Inducible nitric oxide synthase (iNOS) activity was determined by measuring the conversion of radiolabeled arginine to radiolabeled citrulline. RESULTS: Treatment of chondrocytes with adenosine alone had no significant effect on NO release. However, adenosine and NECA inhibited LPS- and rhIL-1alpha-induced NO release. This response was mimicked by forskolin, which acts to increase adenylate cyclase activity, but not by the calcium ionophore A23187 Treatment of chondrocytes with phorbol myristate acetate, which acts to increase protein kinase C activity, potentiated LPS-induced NO release. Adenosine treatment also significantly inhibited the LPS-induced increase in iNOS activity. CONCLUSIONS AND CLINICAL RELEVANCE: Adenosine and the nonspecific adenosine receptor agonist NECA inhibited inflammatory mediator-induced release of NO from equine articular chondrocytes. Modulation of adenosine receptor-mediated pathways may offer novel methods for treatment of inflammation in horses with joint disease.


Asunto(s)
Adenosina/farmacología , Cartílago Articular/enzimología , Condrocitos/enzimología , Caballos/metabolismo , Interleucina-1/farmacología , Lipopolisacáridos/farmacología , Óxido Nítrico Sintasa/metabolismo , Adenosina-5'-(N-etilcarboxamida)/farmacología , Animales , Bradiquinina/farmacología , Calcimicina/farmacología , Cartílago Articular/efectos de los fármacos , Células Cultivadas , Condrocitos/efectos de los fármacos , Interacciones Farmacológicas , Ionóforos/farmacología , Óxido Nítrico Sintasa de Tipo II , Proteína Quinasa C/metabolismo , Agonistas del Receptor Purinérgico P1
6.
Am J Vet Res ; 63(11): 1512-9, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12428660

RESUMEN

OBJECTIVE: To investigate accumulation of extracellular adenosine (ADO) by equine articular chondrocytes and to compare effects of adenosine kinase inhibition and adenosine deaminase inhibition on the amount of nitric oxide (NO) produced by lipopolysaccharide (LPS)-stimulated chondrocytes. SAMPLE POPULATION: Articular cartilage from metacarpophalangeal and metatarsophalangeal joints of 14 horses. PROCEDURE: Chondrocytes were cultured as monolayers, and cells were incubated with LPS, the adenosine kinase inhibitor 5'-iodotubercidin (ITU), or the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride (EHNA). Concentrations of ADO in cell supernatants were measured by use of reverse-phase high-performance liquid chromatography. Effect of inhibition of enzymatic metabolism of ADO on induced NO production was evaluated by exposing cells to a combination of LPS and ITU or LPS and EHNA. RESULTS: Articular chondrocytes accumulated extracellular ADO when exposed to LPS or ITU. Chondrocytes exposed to ITU accumulated ADO in a time-dependent manner. Unstimulated chondrocytes did not accumulate ADO. Similarly, EHNA alone did not produce detectable ADO concentrations; however, addition of EHNA and ITU resulted in a synergistic effect on accumulation of ADO. Lipopolysaccharide-induced NO production was more effectively suppressed by exposure to ITU than to EHNA CONCLUSIONS AND CLINICAL RELEVANCE: Equine articular chondrocytes release ADO in response to the proinflammatory stimulus of bacterial LPS. Inhibition of the metabolism of ADO increases accumulation of extracellular ADO. Autocrine release of ADO from chondrocytes may play a role in the cellular response to tissue damage in arthritic conditions, and pharmacologic modulation of these pathways in joints of arthritic horses could be a potential method of therapy.


Asunto(s)
Adenina/análogos & derivados , Inhibidores de la Adenosina Desaminasa , Adenosina Quinasa/metabolismo , Adenosina/metabolismo , Cartílago Articular/metabolismo , Condrocitos/metabolismo , Inhibidores Enzimáticos/farmacología , Caballos/metabolismo , Adenina/farmacología , Adenosina Desaminasa/metabolismo , Adenosina Quinasa/antagonistas & inhibidores , Animales , Cartílago Articular/citología , Cartílago Articular/efectos de los fármacos , Cartílago Articular/enzimología , Condrocitos/efectos de los fármacos , Condrocitos/enzimología , Lipopolisacáridos/metabolismo , Óxido Nítrico/biosíntesis , Nitritos/análisis , Tubercidina/análogos & derivados , Tubercidina/farmacología
7.
Calcif Tissue Int ; 81(4): 316-26, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17705048

RESUMEN

Adenosine is known to inhibit inflammatory responses in many cell systems via a family of purine receptors termed "P1." The P1 family consists of the adenosine receptors (ADORA) of subtypes A(1), A(2a), A(2b), and A(3). In order to assess whether adenosine has anti-inflammatory actions in osteoblastic cells, we investigated its effects on lipopolysaccharide (LPS)-induced interleukin 6 (IL-6) release in an in vitro inflammatory functional response model. We showed that the osteoblastic cell line MG-63 expresses ADORA(1), A(2a), and A(2b) but not A(3). Treatment of MG-63 cells with adenosine and pharmacological ADORA agonist 5'-N-ethylcarboxamidoadenosine or 2-[4-(2-p-carboxyethyl)phenylamino]-5'-N-ethylcarboxamidoadenosine (CGS21680) inhibits LPS-induced IL-6 release. This inhibition was protein kinase A (PKA)-dependent and mimicked by treatment with the adenylate cyclase activator forskolin. Treatment of MG-63 with the ADORA(2a)-specific antagonist ZM241385 partially reversed the inhibitory effects of ADORA stimulation on LPS-induced IL-6 release. Overall, these data suggest that ADORA(2a) is involved in the regulation of LPS-induced IL-6 release, thus illustrating a regulatory role for adenosine receptors in the control of inflammation and potentially osteoclastogenesis and bone resorption.


Asunto(s)
Adenosina/análogos & derivados , Adenosina/farmacología , Interleucina-6/antagonistas & inhibidores , Interleucina-6/metabolismo , Osteoblastos/metabolismo , Agonistas del Receptor de Adenosina A1 , Agonistas del Receptor de Adenosina A2 , Línea Celular Tumoral , Colforsina/farmacología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Lipopolisacáridos/farmacología , Osteoblastos/efectos de los fármacos , Osteosarcoma/patología , Receptor de Adenosina A1/metabolismo , Receptor de Adenosina A2A/metabolismo , Receptor de Adenosina A2B/metabolismo , Factores de Tiempo
8.
Osteoarthritis Cartilage ; 13(3): 250-7, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15727892

RESUMEN

OBJECTIVE: To investigate the effect of adenosine kinase inhibition on interleukin (IL)-1beta- and lipopolysaccharide (LPS)-induced cartilage damage. DESIGN: Articular cartilage was obtained from the metacarpophalangeal joints of 10 young adult horses. Following a stabilization period, weighed cartilage explants were exposed to IL-1beta (10 ng/ml) or LPS (50 microg/ml) to induce cartilage degradation. To test the potential protective effects of adenosine, these explants were simultaneously exposed to adenosine (100 microM), the adenosine kinase inhibitor 5'iodotubercidin (ITU, 1 microM) or to both adenosine and ITU. After 72 h in culture, conditioned medium was collected for evaluation of glycosaminoglycan (GAG), nitric oxide (NO), prostaglandin E2 (PGE2) and matrix metalloproteinase (MMP)-3 release. RESULTS: IL-1beta and LPS stimulated significant release of GAG, NO, PGE2 and MMP-3. Incubation with ITU significantly inhibited both IL-1beta- and LPS-induced GAG release, but did not alter MMP-3 production. Exposure to ITU also reduced IL-1beta-induced PGE2 release and LPS-induced NO production. Direct adenosine supplementation did not attenuate the effects of IL-1beta or LPS, and the addition of adenosine or ITU in the absence of IL-1beta or LPS did not have any detectable effect on cartilage metabolism in this model. CONCLUSIONS: The adenosine kinase inhibitor ITU attenuated experimentally induced cartilage damage in an in vitro cartilage explant model. Release of adenosine from chondrocytes may play a role in the cellular response to tissue damage in arthritic conditions and modulation of these pathways in the joint may have potential for treatment of arthropathies.


Asunto(s)
Adenosina Quinasa/antagonistas & inhibidores , Cartílago Articular/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Interleucina-1/toxicidad , Lipopolisacáridos/toxicidad , Tubercidina/análogos & derivados , Adenosina/farmacología , Animales , Cartílago Articular/metabolismo , Medios de Cultivo Condicionados , Dinoprostona/metabolismo , Glicosaminoglicanos/metabolismo , Caballos , Interleucina-1/antagonistas & inhibidores , Lipopolisacáridos/antagonistas & inhibidores , Metaloproteinasa 3 de la Matriz/metabolismo , Óxido Nítrico/metabolismo , Técnicas de Cultivo de Tejidos/métodos , Tubercidina/farmacología
9.
Osteoarthritis Cartilage ; 13(4): 345-52, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15780648

RESUMEN

OBJECTIVE: To assess the ability of nonlinear optical microscopy (NLOM) to image ex vivo healthy and degenerative bovine articular cartilage. METHOD: Fresh bovine femoral-tibial joints were obtained from an abattoir. Articular cartilage specimens were harvested from the tibial plateau. Normal and degenerative specimens were imaged by NLOM and subsequently fixed and processed for histological examination. RESULTS: NLOM provided high resolution images of articular cartilage at varying depths with high sensitivity to tissue morphology and high specificity to tissue components without fixing, sectioning or staining. Spectroscopic segmentation of nonlinear optical signals isolated the collagen matrix from the chondron (chondrocyte and non-collagen pericellular matrix). Images from the superficial zone were consistent with the presence of a matrix composed of both elastin-like and collagen fibers distributed in a depth-dependent morphological arrangement, whereas only collagen was demonstrated in the middle and deep zones. Alterations of collagen matrix associated with advanced degenerative joint disease (fibrocartilage) were observed with NLOM. Individual chondrocytes were imaged and demonstrated intracellular fluorescence consistent with the presence of products of intracellular biochemical processes. CONCLUSION: Thin images of living articular cartilage using NLOM may be obtained with (sub-)cellular resolution at varying depths without fixing, sectioning or staining. Extracellular matrical collagen and chondron may be imaged separately in native tissue using spectrally distinct, endogenous, nonlinear optical signals. NLOM was sensitive to macromolecular composition and pathologic changes in articular cartilage matrix. Advances in instrumentation may lead to the application of NLOM to study articular cartilage in vivo.


Asunto(s)
Enfermedades de los Cartílagos/patología , Enfermedades de los Cartílagos/veterinaria , Cartílago Articular/anatomía & histología , Enfermedades de los Bovinos/patología , Animales , Enfermedades de los Cartílagos/metabolismo , Cartílago Articular/química , Cartílago Articular/patología , Bovinos , Enfermedades de los Bovinos/metabolismo , Colágeno/análisis , Microscopía Confocal , Proteoglicanos/análisis , Manejo de Especímenes/métodos
10.
Res Commun Mol Pathol Pharmacol ; 113-114: 275-88, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-15686126

RESUMEN

Pirfenidone is under investigation as an anti-inflammatory and anti-fibrotic agent in several organs including lung. Since important features of arthritic conditions include inflammation and long-term damage to articular cartilage, we have investigated whether PD can suppress chondrocyte responses to bacterial lipopolysaccharide (LPS) and interleukin 1 (IL-1); modulators that induce a cascade of inflammatory responses that lead to articular joint tissue damage. PD (0 - 5microM) showed no effect on cell number or viability when incubated with high density primary equine chondrocyte cultures for a 24 hr period. PD did not stimulate nitric oxide (NO) release by chondrocytes when added alone but LPS and IL-1-induced NO release was inhibited by PD, in a dose-dependent manner. PD did not significantly influence GAG release from cartilage matrix nor did it stimulate or suppress the GAG releasing actions of LPS or IL-1. We conclude that PD is capable of attenuating the cytokine-induced production of the inflammatory mediator, NO by chondrocytes, without stimulating matrix glycosaminoglycan loss from cartilage. PD may have potential as an anti-inflammatory agent in the joint.


Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Cartílago Articular/efectos de los fármacos , Condrocitos/efectos de los fármacos , Óxido Nítrico/biosíntesis , Piridonas/farmacología , Animales , Cartílago Articular/metabolismo , Células Cultivadas , Condrocitos/metabolismo , Glicosaminoglicanos/metabolismo , Caballos , Lipopolisacáridos/antagonistas & inhibidores , Óxido Nítrico/metabolismo
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda