Feasibility of stereotactic MRI-based image guidance for the treatment of vascular malformations: a phantom study.

PURPOSE Treatment of vascular malformations requires the placement of a needle within vessels which may be as small as 1 mm, with the current state of the art relying exclusively on two-dimensional fluoroscopy images for guidance. We hypothesize that the combination of stereotactic image guidance with existing targeting methods will result in faster and more reproducible needle placements, as well as reduced radiationexposure, when compared to standard methods based on fluoroscopy alone. METHODS The proposed navigation approach was evaluated in a phantom experiment designed to allow direct comparison with the conventional method. An anatomical phantom of the left forearm was constructed, including an independent control mechanism to indicate the attainment of the target position. Three interventionalists (one inexperienced, two of them frequently practice the conventional fluoroscopic technique) performed 45 targeting attempts utilizing the combined and 45 targeting attempts utilizing the standard approaches. RESULTS In all 45 attempts, the users were able to reach the target when utilizing the combined approach. In two cases, targeting was stopped after 15 min without reaching the target when utilizing only the C-arm. The inexperienced user was faster when utilizing the combined approach and applied significantly less radiation than when utilizing the conventional approach. Conversely, both experienced users were faster when using the conventional approach, in one case significantly so, with no significant difference in radiation dose when compared to the combined approach. CONCLUSIONS This work presents an initial evaluation of a combined navigation fluoroscopy targeting technique in a phantom study. The results suggest that, especially for inexperienced interventionalists, navigation may help to reduce the time and the radiation dose. Future work will focus on the improvement and clinical evaluation of the proposed method.

Multiple retinal detachment surgery: A functional outcome study. The Houston Vision Assessment Test-Retina (HVAT-Retina)

Retinal detachment is a common ophthalmologic procedure, and outcome is typically measured by a single factor-improvement in visual acuity. Health related functional outcome testing, which quantifies patient's self-reported perception of impairment, can be integrated with objective clinical findings. Based on the patient's self-assessed lifestyle impairment, the physician and patient together can make an informed decision on the treatment that is most likely to benefit the patient. ^ A functional outcome test (the Houston Vision Assessment Test-Retina; HVAT-Retina) was developed and validated in patients with multiple retinal detachments in the same eye. The HVAT-Retina divides an estimated total impairment into subcomponents: contribution of visual disability (potentially correctable by retinal detachment surgery) and nonvisual physical disabilities (co-morbidities not affected by retinal detachment surgery. ^ Seventy-six patients participated in this prospective multicenter study. Seven patients were excluded from the analysis because they were not certain of their answers. Cronbach's alpha coefficient was 0.91 for presurgery HVAT-Retina and 0.94 post-surgery. The item-to-total correlation ranged from 0.50 to 0.88. Visual impairment score improved by 9 points from pre-surgery (p = 0.0003). Physical impairment score also improved from pre-surgery (p = 0.0002). ^ In conclusion, the results of this study demonstrate that the instrument is reliable and valid in patients presenting with recurrent retinal detachments. The HVAT-Retina is a simple instrument and does not burden the patient or the health professional in terms of time or cost. It may be self-administrated, not requiring an interviewer. Because the HVAT-Retina was designed to demonstrate outcomes perceivable by the patient, it has the potential to guide the decision making process between patient and physician. ^

Mouse retinal development: Role of cell adhesion and mechanism of gene regulation

Cell differentiation and pattern formation are fundamental processes in animal development that are under intense investigation. The mouse retina is a good model to study these processes because it has seven distinct cell types, and three well-laminated nuclear layers that form during embryonic and postnatal life. β-catenin functions as both the nuclear effector for the canonical Wnt pathway and a cell adhesion molecule, and is required for the development of various organs. To study the function of β-catenin in retinal development, I used a Cre-loxP system to conditionally ablate β-catenin in the developing retina. Deletion of β-catenin led to disrupted laminar structure but did not affect the differentiation of any of the seven cell types. Eliminating β-catenin did not reduce progenitor cell proliferation, although enhanced apoptosis was observed. Further analysis showed that disruption of cell adhesion was the major cause of the observed patterning defects. Overexpression of β-catenin during retinal development also disrupted the normal retinal lamination and caused a transdifferentiation of neurons into pigmented cells. The results indicate that β-catenin functions as a cell adhesion molecule but not as a Wnt pathway component during retinal neurogenesis, and is essential for lamination but not cell differentiation. The results further imply that retinal lamination and cell differentiation are genetically separable processes. ^ Sonic hedgehog (shh) is expressed in retinal ganglion cells under the control of transcription factor Pou4f2 during retinal development. Previous studies identified a phylogenetically conserved region in the first intron of shh containing a Pou4f2 binding site. Transgenic reporter mice in which reporter gene expression was driven by this region showed that this element can direct gene expression specifically in the retina, but expression was not limited to the ganglion cells. From these data I hypothesized that this element is required for shh expression in the retina but is not sufficient for specific ganglion cell expression. To further test this hypothesis, I created a conditional allele by flanking this region with two loxP sites. Lines carrying this allele will be crossed with retinal-specific Cre lines to remove this element in the retina. My hypothesis predicts that alteration in shh expression and subsequent retinal defects will occur in the retinas of these mice. ^

THE FUNCTIONAL ORGANIZATION OF SYNAPTIC VESICLE POOLS IN A RETINAL BIPOLAR NEURON

Ribbon synapses are found in sensory systems and are characterized by ‘ribbon-like’ organelles that tether synaptic vesicles. The synaptic ribbons co-localize with sites of calcium entry and vesicle fusion, forming ribbon-style active zones. The ability of ribbon synapses to maintain rapid and sustained neurotransmission is critical for vision, hearing and balance. At retinal ribbon synapses, three vesicle pools have been proposed. A rapid pool of vesicles that are docked at the plasma membrane, and whose fusion is limited only by calcium entry, a releasable pool of ATP-primed vesicles whose size also correlates with the number of ribbon-tethered vesicles, and a reserve pool of non-ribbon-tethered cytoplasmic vesicles. However evidence of vesicle fusion at sites away from ribbon-style active zones questions this organization. Another fundamental question underlying the mechanism of vesicle fusion at these synapses is the role of SNARE (Soluble N-ethylmaleimide sensitive factor Attachment Protein Receptor) proteins. Vesicles at conventional neurons undergo SNARE complex-mediated fusion. However a recent study has suggested that ribbon synapses involved in hearing can operate independently of neuronal SNAREs. We used the well-characterized goldfish bipolar neuron to investigate the organization of vesicle pools and the role of SNARE proteins at a retinal ribbon synapse. We blocked functional refilling of the releasable pool and then stimulated bipolar terminals with brief depolarizations that triggered the fusion of the rapid pool of vesicles. We found that the rapid pool draws vesicles from the releasable pool and that both pools undergo release at ribbon-style active zones. To assess the functional role of SNARE proteins at retinal ribbon synapses, we used peptides derived from SNARE proteins that compete with endogenous proteins for SNARE complex formation. The SNARE peptides blocked fusion of reserve vesicles but not vesicles in the rapid and releasable pools, possibly because both rapid and releasable vesicles were associated with preformed SNARE complexes. However, an activity-dependent block in refilling of the releasable pool was seen, suggesting that new SNARE complexes must be formed before vesicles can join a fusion-competent pool. Taken together, our results suggest that SNARE complex-mediated exocytosis of serially-organized vesicle pools at ribbon-style active zones is important in the neurotransmission of vision.

Identification and evaluation of candidate genes for inherited retinal -degenerative diseases

Although more than 100 genes associated with inherited retinal disease have been mapped to chromosomal locations, less than half of these genes have been cloned. This text includes identification and evaluation of candidate genes for three autosomal dominant forms of inherited retinal degeneration: atypical vitelliform macular dystrophy (VMD1), cone-rod dystrophy (CORD), and retinitis pigmentosa (RP). ^ VMD1 is a disorder characterized by complete penetrance but extremely variable expressivity, and includes macular or peripheral retinal lesions and peripappilary abnormalitites. In 1984, linkage was reported between VMD1 and soluble glutamate-pyruvate transaminase GPT); however, placement of GPT to 8q24 on linkage maps had been debated, and VMD1 did not show linkage to microsatellite markers in that region. This study excluded linkage between the loci by cloning GPT, identifying the nucleotide substitution associated with the GPT sozymes, and by assaying VMD1 family samples with an RFLP designed to detect the substitution. In addition, linkage of VMD1 to the known dominant macular degeneration loci was excluded. ^ CORD is characterized by early onset of color-vision deficiency, and decreased visual acuity, However, this retinal degeneration progresses to no light perception, severe macular lesion, and “bone-spicule” accumulations in the peripheral retina. In this study, the disorder in a large Texan family was mapped to the CORD2 locus of 19q13, and a mutation in the retina/pineal-specific cone-rod homeobox gene (CRX) was identified as the disease cause. In addition, mutations in CRX were associated with significantly different retinal disease phenotypes, including retinitis pigmentosa and Leber congenital amaurosis. ^ Many of the mutations leading to inherited retinal disorders have been identified in genes like CRX, which are expressed predominantly in the retina and pineal gland. Therefore, a combination of database analysis and laboratory investigation was used to identify 26 novel retina/pineal-specific expressed sequence tag (EST) clusters as candidate genes for inherited retinal disorders. Eight of these genes were mapped into the candidate regions of inherited retinal degeneration loci. ^ Two of the eight clusters mapped into the retinitis pigmentosa RP13 candidate region of 17p13, and were both determined to represent a single gene that is highly expressed in photoreceptors. This gene, the Ah receptor-interacting like protein-1 (AIPL1), was cloned, characterized, and screened for mutations in RP13 patient DNA samples. ^

Safe abortion: technical and policy guidance for health systems

Esta 2da edición de la Guía recoge la última evidencia disponible no sólo respecto de la atención del aborto seguro sino también de cómo deben organizarse los recursos humanos, los insumos y las instituciones de salud para garantizar los derechos humanos, incluyendo los derechos sexuales y reproductivos de las mujeres.

Practice advisory: interim guidance for care of obstetric patients during a zika virus outbreak

Zika during pregnancy has been associated with birth defects, specifically significant microcephaly. Transmission of Zika to the fetus has been documented in all trimesters; Zika virus RNA has been detected in fetal tissue from early missed abortions, amniotic fluid, term neonates and the placenta. However, much is not yet known about Zika virus in pregnancy. Uncertainties include the incidence of Zika virus infection among pregnant women in areas of Zika virus transmission, the rate of vertical transmission and the rate with which infected fetuses manifest complications such as microcephaly or demise. The absence of this important information makes management and decision making in the setting of potential Zika virus exposure (i.e. travel to endemic areas) or maternal infection, difficult. Currently, there is no vaccine or treatment for this infection.

The XXI century guidance and its social responsibility

El presente trabajo tiene como finalidad considerar la orientación del siglo XXI en Venezuela como una disciplina con un alto compromiso social. Como programa, debe, hoy día, redefinirse con el objeto de impulsar propuestas conducentes a la inclusión de todas aquellas personas, que tradicionalmente han sido excluidas por su raza, etnia, género y/o discapacidad física y que como praxis social esté dirigida a la facilitación de los procesos de desarrollo humano en las dimensiones del Ser, Convivir, Servir, Conocer y Hacer, en el contexto personal, familiar y comunitario a lo largo del continuo del ciclo vital. L as competencias adquiridas a través de los procesos de orientación, son determinantes para proporcionar los medios a las ciudadanas y los ciudadanos para gestionar su propio desarrollo y el de su comunidad Se plantea la necesidad de un cambio de paradigma que deje atrás la clásica postura de un orientador que ayuda al orientado, desde el que conoce, el que tiene experiencia. Se sugiere más bien una relación de orientación intersubjetiva. Por otra parte, se habla de la necesidad de fortalecer el capital social de los espacios que contextualizan el proceso orientador. Se explican además, los alcances del Sistema Nacional de Orientación.

Equity and guidance : The challenge of a proposal

La presente propuesta corresponde a un proyecto de extensión universitaria, acreditado y subsidiado por la Secretaría de Extensión Universitaria de la Universidad Nacional de La Plata. Este plan de trabajo interinstitucional e interdisciplinario formó parte de una de las acciones de transferencia de nuestro último proyecto de investigación denominado La Orientación Vocacional Ocupacional en escuelas denominadas de alta vulnerabilidad psicosocial.

Career guidance in Denmark : Social control in a velvet glove

La Orientación Vocacional en Dinamarca está bien organizada y es altamente profesional. Esto refleja una política orientadora centrada en el papel que la orientación juega como instrumento en el ejercicio de un leve control social. Con este telón de fondo, el dilema de la Orientación en Dinamarca reside en el delicado equilibrio existente entre la orientación considerada como una herramienta para el desarrollo personal, y como un instrumento de control social.

Vocational guidance in people with special educational needs as the result of visual impairment during the transition stage from high school to advanced education

This work proposes to seek for the factors related to the choices that people with special educational needs make as the result of the visual impairment, during the transition stage from high school to advanced education. Therefore, we have taken into consideration that Vocational Guidance and the transition towards adulthood get specific characteristics in case of visually impaired young people, particularly in what's related to continue with advanced education. The focus of this work is to be able to clarify the existence of factors that make this transition stage easier or harder, through the observation of visually impaired and blind people who complete high school. This matter has aroused interest and concern about the strategies to follow to ensure the successful entrance and remaining in the selected advanced education. However, if we don?t know the factors involved in the described fact, it's difficult to design an appropriate intervention strategy. Then, in order to take acknowledge about the specific issues of visually impaired young people who complete high school, we chose a special school for this disability and some students who will join this project