Origin of Retinal Oscillatory Potentials in the Mouse, a Tool to Specifically Locate Retinal Damage.

To determine the origin of oscillatory potentials (OPs), binocular electroretinogram (ERG) recordings were performed under light and dark adaptation on adult healthy C57BL/6J mice. In the experimental group, 1 µL of PBS was injected into the left eye, while the right eye was injected with 1 µL of PBS containing different agents: APB, GABA, Bicuculline, TPMPA, Glutamate, DNQX, Glycine, Strychnine, or HEPES. The OP response depends on the type of photoreceptors involved, showing their maximum response amplitude in the ERG induced by mixed rod/cone stimulation. The oscillatory components of the OPs were affected by the injected agents, with some drugs inducing the complete abolition of oscillations (APB, GABA, Glutamate, or DNQX), whereas other drugs merely reduced the oscillatory amplitudes (Bicuculline, Glycine, Strychnine, or HEPES) or did not even affect the oscillations (TPMPA). Assuming that rod bipolar cells (RBC) express metabotropic Glutamate receptors, GABAA, GABAC, and Glycine receptors and that they release glutamate mainly on Glycinergic AII amacrine cells and GABAergic A17 amacrine cells, which are differently affected by the mentioned drugs, we propose that RBC-AII/A17 reciprocal synapses are responsible for the OP generation in the ERG recordings in the mice. We conclude that the reciprocal synapses between RBC and AII/A17 are the basis of the ERG OP oscillations of the light response, and this fact must be taken into consideration in any ERG test that shows a decrease in the OPs' amplitude.

Tools and Biomarkers for the Study of Retinal Ganglion Cell Degeneration.

The retina is part of the central nervous system, its analysis may provide an idea of the health and functionality, not only of the retina, but also of the entire central nervous system, as has been shown in Alzheimer's or Parkinson's diseases. Within the retina, the ganglion cells (RGC) are the neurons in charge of processing and sending light information to higher brain centers. Diverse insults and pathological states cause degeneration of RGC, leading to irreversible blindness or impaired vision. RGCs are the measurable endpoints in current research into experimental therapies and diagnosis in multiple ocular pathologies, like glaucoma. RGC subtype classifications are based on morphological, functional, genetical, and immunohistochemical aspects. Although great efforts are being made, there is still no classification accepted by consensus. Moreover, it has been observed that each RGC subtype has a different susceptibility to injury. Characterizing these subtypes together with cell death pathway identification will help to understand the degenerative process in the different injury and pathological models, and therefore prevent it. Here we review the known RGC subtypes, as well as the diagnostic techniques, probes, and biomarkers for programmed and unprogrammed cell death in RGC.

Phenotype Characterization of a Mice Genetic Model of Absolute Blindness.

Recent technological development requires new approaches to address the problem of blindness. Such approaches need to be able to ensure that no cells with photosensitive capability remain in the retina. The presented model, Opn4-/- × Pde6brd10/rd10 (O×Rd) double mutant murine, is a combination of a mutation in the Pde6b gene (photoreceptor degeneration) together with a deletion of the Opn4 gene (responsible for the expression of melanopsin in the intrinsically photosensitive retinal ganglion cells). This model has been characterized and compared with those of WT mice and murine animal models displaying both mutations separately. A total loss of pupillary reflex was observed. Likewise, behavioral tests demonstrated loss of rejection to illuminated spaces and a complete decrease in visual acuity (optomotor test). Functional recordings showed an absolute disappearance of various wave components of the full-field and pattern electroretinogram (fERG, pERG). Likewise, visual evoked potential (VEP) could not be recorded. Immunohistochemical staining showed marked degeneration of the outer retinal layers and the absence of melanopsin staining. The combination of both mutations has generated an animal model that does not show any photosensitive element in its retina. This model is a potential tool for the study of new ophthalmological approaches such as optosensitive agents.

Visual Disfunction due to the Selective Effect of Glutamate Agonists on Retinal Cells.

One of the causes of nervous system degeneration is an excess of glutamate released upon several diseases. Glutamate analogs, like N-methyl-DL-aspartate (NMDA) and kainic acid (KA), have been shown to induce experimental retinal neurotoxicity. Previous results have shown that NMDA/KA neurotoxicity induces significant changes in the full field electroretinogram response, a thinning on the inner retinal layers, and retinal ganglion cell death. However, not all types of retinal neurons experience the same degree of injury in response to the excitotoxic stimulus. The goal of the present work is to address the effect of intraocular injection of different doses of NMDA/KA on the structure and function of several types of retinal cells and their functionality. To globally analyze the effect of glutamate receptor activation in the retina after the intraocular injection of excitotoxic agents, a combination of histological, electrophysiological, and functional tools has been employed to assess the changes in the retinal structure and function. Retinal excitotoxicity caused by the intraocular injection of a mixture of NMDA/KA causes a harmful effect characterized by a great loss of bipolar, amacrine, and retinal ganglion cells, as well as the degeneration of the inner retina. This process leads to a loss of retinal cell functionality characterized by an impairment of light sensitivity and visual acuity, with a strong effect on the retinal OFF pathway. The structural and functional injury suffered by the retina suggests the importance of the glutamate receptors expressed by different types of retinal cells. The effect of glutamate agonists on the OFF pathway represents one of the main findings of the study, as the evaluation of the retinal lesions caused by excitotoxicity could be specifically explored using tests that evaluate the OFF pathway.

Deleterious Effect of NMDA Plus Kainate on the Inner Retinal Cells and Ganglion Cell Projection of the Mouse.

Combined administration of N-Methyl-D-Aspartate (NMDA) and kainic acid (KA) on the inner retina was studied as a model of excitotoxicity. The right eye of C57BL6J mice was injected with 1 µL of PBS containing NMDA 30 mM and KA 10 mM. Only PBS was injected in the left eye. One week after intraocular injection, electroretinogram recordings and immunohistochemistry were performed on both eyes. Retinal ganglion cell (RGC) projections were studied by fluorescent-cholerotoxin anterograde labeling. A clear decrease of the retinal "b" wave amplitude, both in scotopic and photopic conditions, was observed in the eyes injected with NMDA/KA. No significant effect on the "a" wave amplitude was observed, indicating the preservation of photoreceptors. Immunocytochemical labeling showed no effects on the outer nuclear layer, but a significant thinning on the inner retinal layers, thus indicating that NMDA and KA induce a deleterious effect on bipolar, amacrine and ganglion cells. Anterograde tracing of the visual pathway after NMDA and KA injection showed the absence of RGC projections to the contralateral superior colliculus and lateral geniculate nucleus. We conclude that glutamate receptor agonists, NMDA and KA, induce a deleterious effect of the inner retina when injected together into the vitreous chamber.

Evaluation of visual function and retinal structure in adult amblyopes.

PURPOSE: To evaluate visual function and its relationship to structure in adult amblyopic subjects. METHODS: This observational, cross-sectional study included 24 adult amblyopes and 19 healthy subjects. The amblyopes were separated into three groups: anisometropic amblyopes (n = 15), strabismic amblyopes (n = 5), and strabismic amblyopes with anisometropia (n = 4). The relationships of the multifocal visual evoked potential (VEP) results with the clinical findings and psychophysical (Humphrey visual field) and structural (spectral domain optical coherence tomography) diagnostic test data were then investigated. RESULTS: Significant differences in the multifocal VEP amplitude responses (abnormal cluster defects), combining the interocular and monocular probability analysis, were observed between the anisometropic amblyopic (80%) and nonamblyopic eyes (13.3%) (p < 0.001), whereas in strabismic amblyopia, such defects were found in 100% of the amblyopic and nonamblyopic eyes. Delayed multifocal VEP interocular and monocular latencies were seen in 66.6 and 26.6% of the anisometropic amblyopic and nonamblyopic eyes, with no significant differences between eyes (p = 0.065). Likewise, latency delays were found in 40% of both strabismic amblyopic and nonamblyopic eyes. Multifocal VEP latency showed significant differences between anisometropic and strabismic amblyopic eyes (p = 0.036). Significant agreement was found between the Humphrey visual field and the multifocal VEP visual field defects in the central area of the visual field (p = 0.033). The average retinal nerve fiber layer thickness, foveal and macular thickness, and macular volume, as measured by spectral domain optical coherence tomography, did not show any significant differences between the amblyopic and nonamblyopic eyes and the control group. CONCLUSIONS: Multifocal VEP amplitudes and latencies were significantly affected in amblyopic eyes and, to a lesser extent, in nonamblyopic eyes. Multifocal VEP response latencies were more delayed in anisometropic eyes than in strabismic eyes, suggesting that anisometropic and strabismic amblyopia may represent different neural abnormalities.

Electroretinographical and histological study of mouse retina after optic nerve section: a comparison between wild-type and retinal degeneration 1 mice.

BACKGROUND: Retinal ganglion cell death underlies the pathophysiology of neurodegenerative disorders such as glaucoma or optic nerve trauma. To assess the potential influence of photoreceptor degeneration on retinal ganglion cell survival, and to evaluate functionality, we took advantage of the optic nerve section mouse model. METHODS: Surviving retinal ganglion cells were double-stained by exposing both superior colliculi to fluorogold, and by applying dextran-tetramethylrhodamine to the injured optic nerve stump. To assess retinal function in wild-type animals, electroretinograms were recorded on the injured eyes and compared with the contralateral. Similar labelling experiments were carried out on retinal degeneration 1 mice. Surviving retinal ganglion cells were counted 21 days after axotomy and compared with wild-type mice. No functional experiments were performed on retinal degeneration 1 animals because they do not develop normal electroretinographical responses. RESULTS: A significant decrease in retinal ganglion cell density was observed 6 days after axotomy in the wild type. Functional studies revealed that, in scotopic conditions, axotomy induced a significant amplitude decrease in the positive scotopic threshold response component of the electroretinogram. Such decrease paralleled cell loss, suggesting it may be an appropriate technique to evaluate functionality. When comparing retinal ganglion cell densities in wild-type and retinal degeneration 1 mice, a significant greater survival was observed on the latter. CONCLUSIONS: After optic nerve section, electroretinographical recordings exhibited a progressive decrease in the amplitude of the positive scotopic threshold response wave, reflecting ganglion cell loss. Interestingly, rod degeneration seemed, at least initially, to protect from axotomy-driven damage.

Role of ON and OFF Visual Pathways in Rod- and Cone-Driven Flicker Responses.

PURPOSE: To evaluate the effects of various retinal neurotransmitters on temporal resolution, particularly, on the Critical Flicker Fusion Frequency (CFF), which has been previously applied in ophthalmic pathophysiologic research. METHODS: A binocular physiologic electroretinogram was performed on adult mice. Animals in the control group were injected in the right eye with 1 µL of phosphate-buffered saline (PBS). Animals in the experimental group were injected in the left eye with 1 µL of PBS and in the right eye with 1 µL of PBS to which different molecules were added: 2-amino-4-phosphonobutyric acid (APB), Glutamate, γ-aminobutyric acid (GABA), 6,7-dinitroquinoxaline-2,3-dione (DNQX), Bicuculline, Glycine, and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES). Initially, rod response was recorded and later the cone response. RESULTS: APB suppressed the rod-driven, but not the cone-driven flicker response. The other agents severely affected the lower flickering frequency response amplitude, in particular, at 3 Hz. The threshold of CFF was lowered from 50 Hz to 40 Hz after applying APB, Glycine, and HEPES. GABA remarkably enhanced rod-driven and cone-driven flicker response at 3 Hz, whereas Glutamate and GABA/Glutamate only did in rod-driven flicker response. CONCLUSIONS: Both ON and OFF visual pathways were implied in cone-driven response, but only the ON visual pathway appears to play a relevant role in rod-driven flicker response. Flicker response seems to be enhanced by horizontal cells both in rod-driven and cone-driven response. In addition, due to the greater sensitivity of the flicker at low frequencies, it is suggested that pathophysiological studies should be carried out at said frequencies.

Oxidative Model of Retinal Neurodegeneration Induced by Sodium Iodate: Morphofunctional Assessment of the Visual Pathway.

Sodium iodate (NaIO3) has been shown to cause severe oxidative stress damage to retinal pigment epithelium cells. This results in the indirect death of photoreceptors, leading to a loss of visual capabilities. The aim of this work is the morphological and functional characterization of the retina and the visual pathway of an animal model of retinal neurodegeneration induced by oxidative stress. Following a single intraperitoneal dose of NaIO3 (65 mg/kg) to C57BL/6J mice with a mutation in the Opn4 gene (Opn4-/-), behavioral and electroretinographic tests were performed up to 42 days after administration, as well as retinal immunohistochemistry at day 57. A near total loss of the pupillary reflex was observed at 3 days, as well as an early deterioration of visual acuity. Behavioral tests showed a late loss of light sensitivity. Full-field electroretinogram recordings displayed a progressive and marked decrease in wave amplitude, disappearing completely at 14 days. A reduction in the amplitude of the visual evoked potentials was observed, but not their total disappearance. Immunohistochemistry showed structural alterations in the outer retinal layers. Our results show that NaIO3 causes severe structural and functional damage to the retina. Therefore, the current model can be presented as a powerful tool for the study of new therapies for the prevention or treatment of retinal pathologies mediated by oxidative stress.

The retina of the PCD/PCD mouse as a model of photoreceptor degeneration. A structural and functional study.

In this work, we used the pcd (Purkinje cell degeneration) mutant mouse with a slow temporal progression of photoreceptor degeneration in order to analyze the structural and functional modifications in the neuronal populations of the outer and inner retina. Retinal immunocytochemistry and functional electroretinography were performed on the pcd/pcd mutant mice and control wild type animals of the C57/DBA strain at 45, 90, 180 and 270 post-natal days. Immunohistochemical studies were performed for a series of protein markers: calbindin, calretinin, PKCα, bassoon, synapsin, syntaxin and islet1. Full field electroretinography recordings were performed on control and dystrophic mice. Rod and mixed responses, and oscillatory potentials, were recorded in dark adapted conditions; cone and flicker responses were recorded under light adaptation. Our results show significant structural modifications in the photoreceptor populations and neurons of the inner retina. Changes in cell morphology affect mainly to the bipolar cells, which gradually lose their dendritic tufts. The electroretinography records reveal that in the pcd retinas the rod and cone systems show a reduction in the amplitude of the electrical signals. This decrease progresses slowly with the passage of time, although for the most advanced stage of photoreceptor degeneration considered, 270 post-natal days, it is still possible to record light induced responses. We conclude that pcd mice experience a loss of retinal function in correlation with the loss of photoreceptors with age, and significant changes in retinal synaptic processes.

Spinal Manipulative Therapy Effects in Autonomic Regulation and Exercise Performance in Recreational Healthy Athletes: A Randomized Controlled Trial.

STUDY DESIGN: A randomized, double blind, parallel groups, sham-controlled trial. OBJECTIVE: The aim of this study was to analyze the acute effects of spinal manipulative therapy (SMT) on performance and autonomic modulation. SUMMARY OF BACKGROUND DATA: The use of SMT is progressively spreading from the clinical to the sporting context owing to its purported ergogenic effects. However, its effects remain unclear. METHODS: Thirty-seven male recreational athletes (aged 37 ±â€Š9 years) who had never received SMT were assigned to a sham (n = 19) or actual SMT group (n = 18). Study endpoints included autonomic modulation (heart rate variability), handgrip strength, jumping ability, and cycling performance [8-minute time trial (TT)]. Differences in custom effects between interventions were determined using magnitude-based inferences. RESULTS: A significant and very likely lower value of a marker of sympathetic modulation, the stress score, was observed in response to actual compared with sham SMT [P = 0.007; effect size (ES) = -0.97]. A trend toward a significant and likely lower sympathetic:parasympathetic ratio (P = 0.055; ES = -0.96) and a likely higher natural logarithm of the root-mean-square differences of successive heartbeat intervals [(LnRMSSD), P = 0.12; ES = 0.36] was also found with actual SMT. Moreover, a significantly lower mean power output was observed during the TT with actual compared with sham SMT (P = 0.035; ES = -0.28). Nonsignificant (P > 0.05) and unclear or likely trivial differences (ES < 0.2) were found for the rest of endpoints, including handgrip strength, heart rate during the TT, and jump loss thereafter. CONCLUSION: A single pre-exercise SMT session induced an acute shift toward parasympathetic dominance and slightly impaired performance in recreational healthy athletes. LEVEL OF EVIDENCE: 2.

Removal of the blue component of light significantly decreases retinal damage after high intensity exposure.

Light causes damage to the retina (phototoxicity) and decreases photoreceptor responses to light. The most harmful component of visible light is the blue wavelength (400-500 nm). Different filters have been tested, but so far all of them allow passing a lot of this wavelength (70%). The aim of this work has been to prove that a filter that removes 94% of the blue component may protect the function and morphology of the retina significantly. Three experimental groups were designed. The first group was unexposed to light, the second one was exposed and the third one was exposed and protected by a blue-blocking filter. Light damage was induced in young albino mice (p30) by exposing them to white light of high intensity (5,000 lux) continuously for 7 days. Short wavelength light filters were used for light protection. The blue component was removed (94%) from the light source by our filter. Electroretinographical recordings were performed before and after light damage. Changes in retinal structure were studied using immunohistochemistry, and TUNEL labeling. Also, cells in the outer nuclear layer were counted and compared among the three different groups. Functional visual responses were significantly more conserved in protected animals (with the blue-blocking filter) than in unprotected animals. Also, retinal structure was better kept and photoreceptor survival was greater in protected animals, these differences were significant in central areas of the retina. Still, functional and morphological responses were significantly lower in protected than in unexposed groups. In conclusion, this blue-blocking filter decreases significantly photoreceptor damage after exposure to high intensity light. Actually, our eyes are exposed for a very long time to high levels of blue light (screens, artificial light LED, neons…). The potential damage caused by blue light can be palliated.

Impairment of photoreceptor ribbon synapses in a novel Pomt1 conditional knockout mouse model of dystroglycanopathy.

Hypoglycosylation of α-dystroglycan (α-DG) resulting from deficiency of protein O-mannosyltransferase 1 (POMT1) may cause severe neuromuscular dystrophies with brain and eye anomalies, named dystroglycanopathies. The retinal involvement of these disorders motivated us to generate a conditional knockout (cKO) mouse experiencing a Pomt1 intragenic deletion (exons 3-4) during the development of photoreceptors, mediated by the Cre recombinase expressed from the cone-rod homeobox (Crx) gene promoter. In this mouse, retinal α-DG was unglycosylated and incapable of binding laminin. Retinal POMT1 deficiency caused significant impairments in both electroretinographic recordings and optokinetic reflex in Pomt1 cKO mice, and immunohistochemical analyses revealed the absence of ß-DG and of the α-DG-interacting protein, pikachurin, in the outer plexiform layer (OPL). At the ultrastructural level, noticeable alterations were observed in the ribbon synapses established between photoreceptors and bipolar cells. Therefore, O-mannosylation of α-DG in the retina carried out by POMT1 is crucial for the establishment of proper synapses at the OPL and transmission of visual information from cones and rods to their postsynaptic neurons.

Effect of diabetes mellitus on Corvis ST measurement process.

PURPOSE: Diabetes mellitus (DM) affects corneal biomechanical parameters. We compared analyses using ORA (Ocular response analyser) and Corvis ST to determine the influence of disease duration, hyperglycaemia and haemoglobin A1c (HbA1c) levels on these parameters. METHODS: This observational, cross-sectional, observer-masked study assessed one eye of 94 consecutive DM patients and 41 healthy subjects. Two DM groups were analysed: the uncontrolled DM group (n = 54) (HbA1c ≥ 7%) and the controlled DM group (n = 40) (HbA1c < 7%). Central corneal thickness (CCT) was measured by ultrasonic pachymetry and intraocular pressure (IOP) by Goldmann applanation tonometry. ORA and Corvis ST analyses were performed to evaluate the changes. RESULTS: Most of the Corvis ST parameters [Deformation amplitude (DA), A1 and A2 times, A1 velocity] in the uncontrolled DM group eyes were found to be significantly different to controls and controlled DM group eyes (p = 0.005, p = 0.001, p < 0.0001, p = 0.002, respectively). DA on the Corvis ST was correlated with blood glucose concentration (p = 0.004) and HbA1c percentage (p = 0.002). ORA corneal hysteresis was significantly lower in diabetic patients with elevated HbA1c than in control subjects (p = 0.001) and was affected by disease duration (p = 0.037), whereas the corneal resistance factor remained unaltered. CONCLUSIONS: A poor glucose control in DM affects corneal biomechanics measured by ORA and Corvis ST, which may cause high IOP measurements independent of CCT. The measurement of the corneal biomechanics should be taken into consideration in the clinical practice.

Neuroprotective Effect of Tauroursodeoxycholic Acid on N-Methyl-D-Aspartate-Induced Retinal Ganglion Cell Degeneration.

Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss.

Effect of topical 0.05% cyclosporine A on corneal endothelium in patients with dry eye disease.

AIM: To determine the effect of topical 0.05% cyclosporine A (CsA) on corneal endothelium in patients with dry eye disease. METHODS: Observational, prospective, case series study. Fifty-five eyes of 29 consecutive patients (9 males and 20 females; median age: 66.8 years, interquartile range: 61-73.2 years) with moderate-severe dry eye disease were evaluated. All patients were treated with topical 0.05% CsA ophthalmic emulsion twice a day in addition to lubricant eyedrops 5 times a day. The follow-up period was 12 months. Before treatment and at 3 and 12 months post-treatment central corneal specular microscopy was performed. The endothelial cell density (ECD), coefficient of variation of cell size (CoV), and percentage of hexagonal cells (Hex %) were analyzed. RESULTS: The median ECDs pre-treatment and at 3 and 12 months post-treatment were 2 352.5/mm(2) (interquartile range, 2 178-2 548.5), 2364/mm(2) (interquartile range, 2 174.25-2 657.5), and 2366 cells/mm(2) (interquartile range, 2 174.75-2 539.75), respectively (P=0.927, one way ANOVA). The median CoVs pre-treatment and at 3 and 12 months post-treatment were 34.5 (interquartile range, 30-37), 35 (interquartile range, 30-38), and 34 (interquartile range, 30.75-38.25), respectively (P=0.7193, one way ANOVA). The median Hex % values pre-treatment and at 3 and 12 months post-treatment were 53 (interquartile range, 47-58), 54 (interquartile range, 45.75-59), and 50.5 (interquartile range, 45.75-58), respectively (P=0.824, one way ANOVA). CONCLUSION: Treatment of patients with dry eye disease for 12 months with topical 0.05% CsA does not seem to cause substantial changes on corneal endothelium.

¿Son suficientes las competencias y el conocimiento de los objetivos en los estudiantes que acceden a la universidad? / Are the competencies and the knowledge of the objectives enough in the students that accede to the university?

Objetivo. Determinar si los estudiantes son conscientes de los objetivos de conocimiento y competencias que deben adquirir en las asignaturas cursadas. Sujetos y métodos. Se pidió a los alumnos del segundo curso de medicina del Centro Universitario de la Defensa que realizaran preguntas de respuesta múltiple sobre los temas de Fisiología Humana II. Simultáneamente, se promocionó la reflexión sobre los objetivos y competencias que debían alcanzarse con dicha asignatura. Para evaluar el conocimiento que los estudiantes tenían de dichos objetivos y competencias, los alumnos cumplimentaron un cuestionario nominal en el que se preguntaba su opinión en relación a la estrategia seguida y al modo en que ellos entendían la asignatura, objetivos, métodos de estudio, etc. Tras la publicación de las calificaciones, y en función de ellas, los alumnos fueron distribuidos en un grupo de mayor rendimiento y otro de menor rendimiento. Las diferencias entre ambos grupos se analizaron a través de los cuestionarios. Resultados. Tras realizar estas actividades se observó una mejora significativa en los resultados de la asignatura mencionada respecto de los obtenidos en Fisiología Humana I. Asimismo, se pudo constatar que el grupo de alumnos de mayor rendimiento estaba más comprometido en llevar a cabo la estrategia docente y tenía más claros los objetivos perseguidos. Conclusión. La práctica de esta estrategia docente mejora el rendimiento académico. Además, se pone de manifiesto que cuanto más claros tienen los objetivos y competencias que deben obtener, mejores resultados consiguen (AU)

Aim. To determine if the students are aware of the knowledge objectives and competences that should be acquired in the courses. Subjects and methods. Students of the second course in Medical School of the Centro Universitario de la Defensa were asked to make multiple choice questions on the Human Physiology II subject. At the same time, it was promoted the reflection on the objectives and competences that had to be reached with this subject. In order to determine the students' knowledge of these objectives and competences, the students completed a nominal questionnaire telling their opinion about the strategy followed and the way in which they understood the subject, objectives, methods of study, etc. Following the publication of the qualifications, and depending on such qualifications, pupils were distributed in a group of higher performance and in other of lower performance group. Differences in both groups were analyzed through the questionnaires. Results. After these activities, there was a significant improvement in the academic score, respect to Human Physiology I. Also, it was possible to verify that the group of students of greater performance was more committed in carrying out the educational strategy and they had clearer the objectives pursued. Conclusion. The practice of this teaching strategy improves academic performance. In addition, the clearer the competencies and objectives, the better results they will get (AU)

Formulación de preguntas de respuesta múltiple: un modelo de aprendizaje basado en competencias / Formulation of multiple-choice questions: a model of competency-based learning

Introducción: El objetivo fundamental de la presente innovación ha sido combatir la tendencia del alumnado a la pasividad para que sea él mismo quien construya su propio conocimiento relevante y personal. Las estrategias para obtenerlo son la promoción del aprendizaje mediante la práctica de las competencias transversales y de su control mediante el fomento de la autoevaluación reflexiva por parte del estudiante. Sujetos y métodos. Se solicitó a los alumnos que elaborasen preguntas de respuesta múltiple acompañándolas de la argumentación correspondiente a su contenido. Al término de la experiencia se entregó al alumnado un cuestionario donde se preguntaba su opinión sobre distintos aspectos del proyecto. Resultados. El análisis de las calificaciones de los alumnos que intervinieron en el proyecto demostró una mejora objetiva y estadísticamente significativa en su rendimiento. Por otro lado, las respuestas al cuestionario mostraron que una mejor comprensión de los objetivos de la asignatura y del propio proceso de aprendizaje por parte del alumnado llevaban a la optimización de sus resultados académicos. Conclusión. La formulación de preguntas de respuesta múltiple por parte del estudiante resulta un medio especialmente útil en el aprendizaje de contenidos, además de permitir el desarrollo de las correspondientes competencias transversales y específicas. Por otro lado, promover la autoevaluación del estudiante resulta completamente necesario para alcanzar los objetivos docentes

Introduction: The main objective of this innovation has been to fight against the students’ tendency to passivity and to encourage them to build their own personal and relevant knowledge. The strategies to achieve this are to promote learning through the practice of transversal competences and to control it by encouraging reflective self-evaluation. Subjects and methods: The students were asked to write multiple choice questions and the arguments to justify the answers. After the experience, the students completed a questionnaire in which they expressed their views on various aspects of the project. Results: The analysis of the academic scores of those students who took part in the project, showed an objective and statistically significant improvement in performance. Conclusion: Formulation of multiple choice questions by the students is a particularly useful tool for content learning, as well as for the development of transversal and specific competences. On the other hand, it is absolutely necessary to promote student self-assessment in order to reach the educational objectives

Effect of intravitreal ranibizumab on corneal endothelium in age-related macular degeneration.

PURPOSE: To determine the effect of intravitreal injection of ranibizumab on the corneal endothelium in patients with choroidal neovascularization in age-related macular degeneration. METHODS: Observational prospective case series study. Fifty-two eyes of 52 consecutive patients (29 men, 23 women; age range, 61-80 years) were evaluated. All participants received monthly intravitreal injections of (0.05 mL, 0.5 mg) ranibizumab for 3 consecutive months; the follow-up period was 6 months. Central corneal specular microscopy was performed before injection and at 7 days and 6 months after the first intravitreal injection. The endothelial cell density, coefficient of variation of cell size, and percentage of hexagonal cells were analyzed, and the central corneal thickness was measured. RESULTS: There were no significant differences in the endothelial cell densities, coefficient of variation of cell sizes, and percentage of hexagonal cells values before injection and at 7 days and 6 months after the first intravitreal ranibizumab injection (P = 0.987, P = 0.822, and P = 0.918, respectively). There was also no significant difference in central corneal thickness measurements before injection and at 7 days and 6 months after the first intravitreal ranibizumab injection (P = 0.325). CONCLUSION: Repeated intravitreal injections of 0.5 mg of ranibizumab do not seem to cause substantial changes in the corneal endothelium at 6 months.

La educación por competencias como medio para facilitar la toma de control del aprendizaje por el estudiante / Competency-based education as a way to facilitate the take over of learning by the student

Introducción: Clásicamente, el papel de los alumnos ha sido el de elemento pasivo en el marco de una enseñanza monodireccional donde el alumno tenía pocas posibilidades de controlar su aprendizaje y, por tanto, de implicarse activamente en él. Materiales y métodos: Para fomentar la toma de control del aprendizaje por el alumnado se han diseñado unas estrategias consistentes en la aplicación de una serie de competencias transversales. Se ha elegido como asignatura la fisiopatología del Grado de Fisioterapia del curso 2011-2012 porque su gran proporción de seminarios permite una mayor participación del alumnado. Después, se han seleccionado una serie de competencias: la capacidad de búsqueda de información y evaluación crítica, la capacidad de análisis y síntesis, la capacidad de dar respuesta adecuada a las preguntas, la capacidad crítica sobre lo leído y escuchado plasmada en forma de preguntas y, por último, la claridad y calidad en la exposición oral de un tema previamente propuesto. Resultados: Con la implantación y desarrollo de las competencias designadas, además de mejorar dichas competencias, las calificaciones del alumnado han mejorado de forma estadísticamente significativa respecto de las de los dos cursos anteriores (test exacto de Fisher). De forma global, en el curso en que se ha implementado la innovación, un 82% del alumnado superó el curso en la convocatoria ordinaria, respecto al 53% y el 44% de los dos cursos anteriores. Conclusión: Las actividades que se realizan para lograr la adquisición de las competencias transversales fundamentales facilitan a los estudiantes la toma de control de su aprendizaje y mejoran dicho aprendizaje

Introduction: Traditionally, the students' role has been a passive element in the framework of a one-way teaching process, where students had few perspectives of controlling their learning and, therefore, of actively getting involved on it. Materials and methods: In order to promote the take over of learning by the students, a series of strategies, which consisted on applying a series of transversal competences, were designed. The subject chosen for this purpose was Pathophysiology, belonging to the Degree in Physiotherapy of the academic year 2011/2012, because the relative high amount of seminars in this subject enables a great student participation. Then, a range of competences were selected, such as the ability to search for information and critically evaluate it; the capacity for analysis and synthesis; the capacity to adequately answer questions; the critical thinking ability concerning what has been read and heard, that is translated into the capacity of making questions about the subject; and, finally, the clarity and quality when presenting orally a previously proposed topic. Results: With the implementation and development of the designated competences, in addition to the enhancement of these skills in the students, their scores improved in a statistically significant manner with respect to those from the two previous years (Fisher's exact test). In the academic year which this innovation was implemented, 82% of the students passed the course in the ordinary call, as compared to 53% and 44% of the two previous years. Conclusion: The activities carried out to achieve the acquisition of key transversal competences have facilitated the students to take over control of their own learning and, importantly, to make it more efficient