Browsing by Subject "Image Processing"

Now showing 1 - 4 of 4
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    A differential structure approach to membrane segmentation in electron tomography
    (2011-09) Martinez-Sanchez, Antonio; Inmaculada, García; Fernández, Jose-Jesús; Ingeniería de la Información y las Comunicaciones
    Electron tomography allows three-dimensional visualization of cellular landscapes in molecular detail. Segmentation is a paramount stage for the interpretation of the reconstructed tomograms. Although several computational approaches have been proposed, none has prevailed as a generic method and thus segmentation through manual annotation is still a common choice. In this work we introduce a segmentation method targeted at membranes, which define the natural limits of compartments within biological specimens. Our method is based on local differential structure and on a Gaussian-like membrane model. First, it isolates information through scale-space and finds potential membrane-like points at a local scale. Then, the structural information is integrated at a global scale to yield the definite segmentation. We show and validate the performance of the algorithm on a number of tomograms under different experimental conditions.
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    A ridge-based framework for segmentation of 3D electron microscopy datasets
    (Elsevier, 2013-01) Martinez-Sanchez, Antonio; García, Inmaculada; Fernández, Jose-Jesús; Ingeniería de la Información y las Comunicaciones
    Three-dimensional (3D) electron microscopy (EM) has become a major player in structural cell biology as it enables the analysis of subcellular architecture at an unprecedented level of detail. Interpretation of the resulting 3D volumes strongly depends on segmentation, which consists in decomposing the volume into their structural components. The computational approaches proposed so far have not turned out to be of general applicability. Thus, manual segmentation still remains a prevalent method. Here, a new computational framework for segmentation of 3D EM datasets is introduced. It relies on detection and characterization of ridges (i.e. local maxima). The detected ridges are modelled as asymmetric Gaussian functions whose parameters constitute ridge descriptors. This local information is then used to cluster the ridges, which leads to the ultimate segmentation. In this work we focus on membranes and locally planar structures in general. The performance of the framework is illustrated with its application to a number of complex 3D datasets and a quantitative analysis.
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    Anti-inflammatory effects of enemas containing an oily extract of curcumin in an experimental model of diversion colitis
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Jaoudat Kadri, Caled; Aires Pereira, José; Guilherme Campos, Fábio; Marques Ortega, Manoela; Benediti Bragion, Celene; Real Martinez, Carlos Augusto
    Curcumin has powerful anti-inflammatory and antioxidant effects and it has been used for treatment of distal ulcerative colitis. The therapeutic effects of curcumin have not yet been evaluated in diversion colitis. The aim of the present study was to evaluate the anti-inflammatory effects of curcumin on colonic mucosa devoid of a faecal stream. Thirty-six rats were subjected to a proximal colostomy and distal colonic fistulation. They were divided into two groups, which were sacrificed two or four weeks after the intervention. Each group was divided into three subgroups treated with the daily application of enemas containing saline or an oily extract of curcumin at 50 mg/kg/day or 200 mg/kg/day. Colitis was diagnosed by histological analysis. Inflammatory grades were assessed using a previously validated scoring system. The infiltration of neutrophils was evaluated based on the tissue expression of myeloperoxidase (MPO), as determined by immunohistochemistry, and a computer-assisted image analysis program. The Mann-Whitney test was used to compare inflammation grades and myeloperoxidase levels among groups, and ANOVA was used to verify the variance over time, with the level of significance set at 5% (p<0.05) for both tests. Enemas containing curcumin improved the inflammation of the mucosa without a faecal stream and reduced the tissue contents of MPO. MPO tissue levels did not vary with time or between the concentrations of curcumin used. Enemas with curcumin improved the inflammation of the colonic mucosa, reduced the inflammatory grade and decreased the tissue content of MPO in colon segments without a faecal stream.
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    Infrared thermography, intratendon vascular resistance and echotexture in athletes with patellar tendinopathy: a cross-sectional study
    (SAGE Publications, 2023-03) Molina Payá, Francisco J.; Ríos Díaz, José; Carrasco Martínez, Francisco; Martínez Payá, Jacinto Javier; Fisioterapia
    Background: Ultrasonographic signs of tendinopathies are an increase in thickness, loss of alignment in collagen fibers and the presence of neovascularization. Nevertheless, analysis of intratendinous vascular resistance (IVR) can be more useful for understanding the physiological state of the tissue. Objective: To show thermal, echotextural and Doppler signal differences in athletes with patellar tendinopathy and controls. Methods: Twenty-six athletes with patellar tendinopathy (PT) participants (30.1 yrs; SD= 9.0 yrs) and 27 asymptomatic athletes (23.3 yrs; SD= 5.38 yrs) were evaluated with thermographic and Doppler ultrasonography (DS). Area of Doppler signals (DS), echotextural parameters (echointensity and echovariation) and IVR were determined by image analysis. The statistical analysis was performed by Bayesian methods and the results were showed by Bayes Factor (BF10: probability of alternative hypothesis over null hypothesis), and Credibility intervals (CrI) of the effect. Results: The absolute differences of temperature (TD) were clearly greater (BF10= 19) in the tendinopathy group (patients) than in controls. Regarding temperature differences between the affected and healthy limb, strong evidence was found (BF10= 14) for a higher temperature (effect= 0.53 ºC; 95% CrI=0.15 to 0.95 ºC) and very strong for reduced IVR compared (BF10= 71) (effect= -0.67; 95% CrI=- 1.10 to -0.25). The differences in area of DS (BF10= 266) and EV (BF10= 266) were higher in tendinopathy group. TD showed a moderate positive correlation with VISA-P scores (tau-B=.29; 95% CrI=.04 to .51) and strong correlation with IVR (r=-.553; 95%CrI=-.75 to -.18). Conclusion: Athletes with patellar tendinopathy showed a more pronounced thermal difference, a larger area of Doppler signal, a lower IVR and a moderately higher echovariaton than controls. The correlation between temperature changes and IVR might be related with the coexistence of degenerative and inflammatory process in PT.