A rare case of an idiopathic extraocular muscle abscess

Diplopia has a diverse range of ophthalmological, neurological, autoimmune, neoplastic and infectious causes. However it is very rare for an extraocular muscle abscess to occur. A skeletal muscle abscess usually occurs in the thigh and trunk muscles and is most commonly caused by Staphylococcus aureus.1 The purpose of this case report is to describe this condition we came across in our eye casualty department in a healthy teenager who presented with painful diplopia and this was due to a lateral rectus muscle abscess. Complete resolution of the diplopia occurred by 6 weeks from starting treatment. The possible aetiologies and possible complications of such a condition are then discussed. An idiopathic extraocular muscle abscess is a rare condition which should be included in the differential diagnosis of a patient presenting with painful double vision.peer-reviewe

Impairing one sensory modality enhances another by reconfiguring peptidergic signalling in Caenorhabditis elegans

Animals that lose one sensory modality often show augmented responses to other sensory inputs. The mechanisms underpinning this cross-modal plasticity are poorly understood. We probe such mechanisms by performing a forward genetic screen for mutants with enhanced O2 perception in Caenorhabditis elegans. Multiple mutants exhibiting increased O2 responsiveness concomitantly show defects in other sensory responses. One mutant, qui-1, defective in a conserved NACHT/WD40 protein, abolishes pheromone-evoked Ca2+ responses in the ADL pheromone-sensing neurons. At the same time, ADL responsiveness to pre-synaptic input from O2-sensing neurons is heightened in qui-1, and other sensory defective mutants, resulting in enhanced neurosecretion although not increased Ca2+ responses. Expressing qui-1 selectively in ADL rescues both the qui-1 ADL neurosecretory phenotype and enhanced escape from 21% O2. Profiling ADL neurons in qui-1 mutants highlights extensive changes in gene expression, notably of many neuropeptide receptors. We show that elevated ADL expression of the conserved neuropeptide receptor NPR-22 is necessary for enhanced ADL neurosecretion in qui-1 mutants, and is sufficient to confer increased ADL neurosecretion in control animals. Sensory loss can thus confer cross-modal plasticity by changing the peptidergic connectome

Neuronal calmodulin levels are controlled by CAMTA transcription factors

The ubiquitous Ca2+ sensor calmodulin (CaM) binds and regulates many proteins, including ion channels, CaM kinases, and calcineurin, according to Ca2+-CaM levels. What regulates neuronal CaM levels, is, however, unclear. CaM-binding transcription activators (CAMTAs) are ancient proteins expressed broadly in nervous systems and whose loss confers pleiotropic behavioral defects in flies, mice, and humans. Using Caenorhabditis elegans and Drosophila, we show that CAMTAs control neuronal CaM levels. The behavioral and neuronal Ca2+ signaling defects in mutants lacking camt-1, the sole C. elegans CAMTA, can be rescued by supplementing neuronal CaM. CAMT-1 binds multiple sites in the CaM promoter and deleting these sites phenocopies camt-1. Our data suggest CAMTAs mediate a conserved and general mechanism that controls neuronal CaM levels, thereby regulating Ca2+ signaling, physiology, and behavior

Audit on A-scan use prior to cataract surgery in Mater Dei Hospital

The A-scan is a method of measurement of the ocular axial length (L). It is coupled with corneal curvature keratometry (K) readings so that one can measure the required power (P) of an intraocular lens (IOL) used for cataract surgery. The Sanders, Retzlaff and Kraft (SRK) formula calculates the required P of the IOL as P = A − 2.5L − 0.9K where A is the specific IOL constant. The power of the lens determines the refraction of the image onto the retina and thus determines the visual acuity of the eye. The axial length of the eye is measured by the time a signal takes to be reflected back to the source, like ultrasound or light. Distance is calculated by the velocity formula, depending on the speed of the signal. In Mater Dei hospital, two methods are used to determine the axial length of the eye prior to cataract surgery, namely an ultrasound method and an optical method.peer-reviewe

Experience-Dependent Modulation of C. elegans Behavior by Ambient Oxygen

SummaryBackground: Ambient oxygen (O2) influences the behavior of organisms from bacteria to man. In C. elegans, an atypical O2 binding soluble guanylate cyclase (sGC), GCY-35, regulates O2 responses. However, how acute and chronic changes in O2 modify behavior is poorly understood.Results: Aggregating C. elegans strains can respond to a reduction in ambient O2 by a rapid, reversible, and graded inhibition of roaming behavior. This aerokinetic response is mediated by GCY-35 and GCY-36 sGCs, which appear to become activated as O2 levels drop and to depolarize the AQR, PQR, and URX neurons. Coexpression of GCY-35 and GCY-36 is sufficient to transform olfactory neurons into O2 sensors. Natural variation at the npr-1 neuropeptide receptor alters both food-sensing and O2-sensing circuits to reconfigure the salient features of the C. elegans environment. When cultivated in 1% O2 for a few hours, C. elegans reset their preferred ambient O2, seeking instead of avoiding 0%–5% O2. This plasticity involves reprogramming the AQR, PQR, and URX neurons.Conclusions: To navigate O2 gradients, C. elegans can modulate turning rates and speed of movement. Aerotaxis can be reprogrammed by experience or engineered artificially. We propose a model in which prolonged activation of the AQR, PQR, and URX neurons by low O2 switches on previously inactive O2 sensors. This enables aerotaxis to low O2 environments and may encode a “memory” of previous cultivation in low O2

Interactome analysis of Caenorhabditis elegans synapses by TurboID-based proximity labeling

Proximity labeling provides a powerful in vivo tool to characterize the proteome of subcellular structures and the interactome of specific proteins. The nematode Caenorhabditis elegans is one of the most intensely studied organisms in biology, offering many advantages for biochemistry. Using the highly active biotin ligase TurboID, we optimize here a proximity labeling protocol for C. elegans. An advantage of TurboID is that biotin's high affinity for streptavidin means biotin-labeled proteins can be affinity-purified under harsh denaturing conditions. By combining extensive sonication with aggressive denaturation using SDS and urea, we achieved near-complete solubilization of worm proteins. We then used this protocol to characterize the proteomes of the worm gut, muscle, skin, and nervous system. Neurons are among the smallest C. elegans cells. To probe the method's sensitivity, we expressed TurboID exclusively in the two AFD neurons and showed that the protocol could identify known and previously unknown proteins expressed selectively in AFD. The active zones of synapses are composed of a protein matrix that is difficult to solubilize and purify. To test if our protocol could solubilize active zone proteins, we knocked TurboID into the endogenous elks-1 gene, which encodes a presynaptic active zone protein. We identified many known ELKS-1-interacting active zone proteins, as well as previously uncharacterized synaptic proteins. Versatile vectors and the inherent advantages of using C. elegans, including fast growth and the ability to rapidly make and functionally test knock-ins, make proximity labeling a valuable addition to the armory of this model organism

Integración de alumnos e investigadores docentes en el proceso de evaluación de la asignatura metodología de la investigación en ciencias de la salud

Ponencia presentada en la II Muestra Nacional de Innovaciones en la Enseñanza de la Odontología y IV Muestra Institucional de Innovaciones en la Enseñanza de la Odontología. Córdoba, 13 y 14 de septiembre de 2012.La asignatura Metodología de la Investigación en Ciencias de la Salud se dicta en el segundo cuatrimestre de la carrera de Odontología. Los contenidos organizados siguiendo los momentos del proceso de investigación científica, se presentan a través de actividades de enseñanza y aprendizaje que ponen en juego diferentes habilidades mentales y actitudes sociales positivas, con el propósito de facilitar un aprendizaje significativo. Como estrategia de evaluación se propuso a los alumnos, la observación y análisis de la metodología científica descripta en los trabajos presentados en formato poster en las lll Jornadas de Investigación Odontológicas de la Facultad de Odontología y su posterior presentación frente a sus pares y docente.Fil: Bono, Alejandra. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Bregains, Liliana. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Cismondi, Adriana. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: De Caso, Cecilia. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Fontanetti, Pablo. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Francia, Catalina. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Gigena, Pablo. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Llanes, Mario. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Morelatto, Rosana. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Plavnik, Luis. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Sezin, Mario. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina.Fil: Theiler, Gerardo. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Metodología de la Investigación en Ciencias de la Salud; Argentina

Comparative Survival of Asian and White Metastatic Castration-Resistant Prostate Cancer Men Treated With Docetaxel

There are few data regarding disparities in overall survival (OS) between Asian and white men with metastatic castration-resistant prostate cancer (mCRPC). We compared OS of Asian and white mCRPC men treated in phase III clinical trials with docetaxel and prednisone (DP) or a DP-containing regimen. Individual participant data from 8820 men with mCRPC randomly assigned on nine phase III trials to receive DP or a DP-containing regimen were combined. Men enrolled in these trials had a diagnosis of prostate adenocarcinoma. The median overall survival was 18.8 months (95% confidence interval [CI] = 17.4 to 22.1 months) and 21.2 months (95% CI = 20.8 to 21.7 months) for Asian and white men, respectively. The pooled hazard ratio for death for Asian men compared with white men, adjusted for baseline prognostic factors, was 0.95 (95% CI = 0.84 to 1.09), indicating that Asian men were not at increased risk of death. This large analysis showed that Asian men did not have shorter OS duration than white men treated with docetaxel