RESUMEN
Ultrasonography is the lowest cost no risk medical imaging technique. However, reading an ultrasonographic (US) image as well as performing a good US probe positioning remain difficult tasks. Education in this domain is today performed on patients, thus limiting it to the most common cases. In this paper, we present a cost effective simulator that allows US image practice and realistic probe manipulation from CT data. More precisely, we tackle the issue of providing a realistic interface for the probe manipulation with a basic haptic feedback.
Asunto(s)
Biorretroalimentación Psicológica/instrumentación , Instrucción por Computador/métodos , Modelos Biológicos , Tacto , Ultrasonografía/instrumentación , Ultrasonografía/métodos , Interfaz Usuario-Computador , Biorretroalimentación Psicológica/métodos , Simulación por Computador , Análisis Costo-Beneficio , Francia , Humanos , Interpretación de Imagen Asistida por Computador/instrumentación , Interpretación de Imagen Asistida por Computador/métodos , Enseñanza/métodos , Transductores/economía , Ultrasonografía/economíaRESUMEN
The functional partitioning of the cerebellar cortex depends on the projection patterns of its afferent and efferent neurons. However, the entire morphology of individual projection neurons has been demonstrated in only a few classes of neurons in the vertebrate CNS. To investigate the contribution of the projection pattern of individual olivocerebellar axons to the cerebellar functional compartmentalization, we labeled individual olivocerebellar axons, which terminate in the cerebellar cortex as climbing fibers, with biotinylated dextran amine injected into the inferior olive in the rat, and completely reconstructed the entire trajectories of 34 olivocerebellar axons from serial sections of the cerebellum and medulla. Single axons had seven climbing fibers on average, which terminated at similar distances from the midline in a single or in multiple lobules. Cortical projection areas of adjacent olivary neurons were clustered as narrow but separate longitudinal segments and often innervated by collaterals of single neurons. Comparison of the cerebellar distribution of olivocerebellar axons arising from different sites within a single olivary subnucleus indicated that slightly distant neurons projected to complementary sets of such segments in a single longitudinal band. Several of these longitudinal bands formed a so-called parasagittal zone innervated by a subnucleus of the inferior olive. Single olivocerebellar axons projected rostrocaudally to segments within a single band but did not project mediolaterally to multiple bands. These results suggest fine substructural organization in the cerebellar compartmentalization that may represent functional units.
Asunto(s)
Axones/fisiología , Biotina/análogos & derivados , Cerebelo/citología , Núcleo Olivar/citología , Animales , Corteza Cerebelosa/citología , Dextranos , Vías Nerviosas/citología , Neuronas Aferentes/citología , Ratas , Ratas Long-EvansRESUMEN
Since arginine can stimulate lymphocyte proliferation in the healthy human, its effect on lymphocyte proliferation in vitro was studied in 7 patients with far advanced gastric cancer. These patients with normal nourishment were ambulatory and could consume a regular diet. A daily dietary supplement of 30 g arginine for 7 days did not alter the total lymphocyte counts or the T/B cell ratio in the peripheral blood. Enhancement of lymphocyte proliferation in response to mitogen stimulation was not observed. Furthermore, an in vitro study on the effect of arginine on phytohemagglutinin-stimulated lymphocyte proliferation showed that lymphocytes from gastric cancer patients had poorer responses than those obtained from normal subjects, despite the supplement in the culture medium with normal serum, patient serum, or fetal bovine serum. Arginine ingestion did not impair liver function and had no detectable side effects except transient nausea in 1 patient. These results indicate that dietary arginine supplement appears safe but does not stimulate lymphocyte function in far advanced gastric cancer patients. The suppressed immune function in gastric cancer patients may be the result of their intrinsic lymphocyte defect.