No abstract

No abstract

No abstract

This is a prospective study of 108 patients in two distinct groups undergoing real-time ultrasonography (US) and ascending conventional venography within the same day. The two patient groups consisted of the following: Those patients evaluated because of suspicion of deep venous thrombosis of lower limbs (69 patients) and those at high risk for venous thrombosis (19 patients with a recent hip fracture, 20 with a suspected pulmonary embolism). In the diagnosis group 48 patients had venographic evidence of thrombosis. The predictive value of abnormal findings from real-time US was 97%, and that of a negative study was 75%. Thus, real-time US may have a role as a diagnostic procedure, to be followed by x-ray venography in patients with negative US results. By contrast, real-time US is far less sensitive as a screening test in patients without clinical evidence of thrombosis. Only 3 of 9 patients with thrombosis were detected, with a 50% sensitivity for proximal vein thrombosis. Therefore, the use of real-time US for screening high-risk patients must be limited to very high risk patients in whom other tests are ineffective (as in hip surgery).

Tuberculosis (TB) is an infectious disease that still causes more than 1.5 million deaths annually. The World Health Organization estimates that around 30% of the world's population is latently infected. However, the mechanisms responsible for 10% of this reserve (i.e., of the latently infected population) developing an active disease are not fully understood, yet. The dynamic hypothesis suggests that endogenous reinfection has an important role in maintaining latent infection. In order to examine this hypothesis for falsifiability, an agentbased model of growth, merging, and proliferation of TB lesions was implemented in a computational bronchial tree, built with an iterative algorithm for the generation of bronchial bifurcations and tubes applied inside a virtual 3D pulmonary surface. The computational model was fed and parameterized with computed tomography (CT) experimental data from 5 latently infected minipigs. First, we used CT images to reconstruct the virtual pulmonary surfaces where bronchial trees are built. Then, CT data about TB lesion' size and location to each minipig were used in the parameterization process. The model's outcome provides spatial and size distributions of TB lesions that successfully reproduced experimental data, thus reinforcing the role of the bronchial tree as the spatial structure triggering endogenous reinfection. A sensitivity analysis of the model shows that the final number of lesions is strongly related with the endogenous reinfection frequency and maximum growth rate of the lesions, while their mean diameter mainly depends on the spatial spreading of new lesions and the maximum radius. Finally, the model was used as an in silico experimental platform to explore the transition from latent infection to active disease, identifying two main triggering factors: a high inflammatory response and the combination of a moderate inflammatory response with a small breathing amplitude.