Antonia Charchanti

Automated Detection of Cell Nuclei in Pap Smear Images Using Morphological Reconstruction and Clustering

In this paper, we present a fully automated method for cell nuclei detection in Pap smear images. The locations of the candidate nuclei centroids in the image are detected with morphological analysis and they are refined in a second step, which incorporates a priori knowledge about the circumference of each nucleus. The elimination of the undesirable artifacts is achieved in two steps: the application of a distance-dependent rule on the resulted centroids; and the application of classification algorithms. In our method, we have examined the performance of an unsupervised (fuzzy C-means) and a supervised (support vector machines) classification technique. In both classification techniques, the effect of the refinement step improves the performance of the clustering algorithm. The proposed method was evaluated using 38 cytological images of conventional Pap smears containing 5617 recognized squamous epithelial cells. The results are very promising, even in the case of images with high degree of cell overlapping.

Modernization of an anatomy class: From conceptualization to implementation. A case for integrated multimodal–multidisciplinary teaching

It has become increasingly apparent that no single method for teaching anatomy is able to provide supremacy over another. In an effort to consolidate and enhance learning, a modernized anatomy curriculum was devised by attempting to take advantage of and maximize the benefits from different teaching methods. Both the more traditional approaches to anatomy teaching, as well as modern, innovative educational programs were embraced in a multimodal system implemented over a decade. In this effort, traditional teaching with lectures and dissection was supplemented with models, imaging, computer‐assisted learning, problem‐based learning through clinical cases, surface anatomy, clinical correlation lectures, peer teaching and team‐based learning. Here, we review current thinking in medical education and present our transition from a passive, didactic, highly detailed anatomy course of the past, to a more interactive, as well as functionally and clinically relevant anatomy curriculum over the course of a decade. Anat Sci Educ.

Combining shape, texture and intensity features for cell nuclei extraction in Pap smear images

In this work, we present an automated method for the detection and boundary determination of cells nuclei in conventional Pap stained cervical smear images. The detection of the candidate nuclei areas is based on a morphological image reconstruction process and the segmentation of the nuclei boundaries is accomplished with the application of the watershed transform in the morphological color gradient image, using the nuclei markers extracted in the detection step. For the elimination of false positive findings, salient features characterizing the shape, the texture and the image intensity are extracted from the candidate nuclei regions and a classification step is performed to determine the true nuclei. We have examined the performance of two unsupervised (K-means, spectral clustering) and a supervised (Support Vector Machines, SVM) classification technique, employing discriminative features which were selected with a feature selection scheme based on the minimal-Redundancy-Maximal-Relevance criterion. The proposed method was evaluated on a data set of 90 Pap smear images containing 10,248 recognized cell nuclei. Comparisons with the segmentation results of a gradient vector flow deformable (GVF) model and a region based active contour model (ACM) are performed, which indicate that the proposed method produces more accurate nuclei boundaries that are closer to the ground truth.

Nerve repair : Experimental and clinical evaluation of neurotrophic factors in peripheral nerve regeneration

SUMMARY Neurotrophic factors are a family of polypeptides required for survival of discrete neuronal populations. In the normal state such factors are mostly synthesised by target tissues and are used for the viability of the nerve-cell bodies. After nerve injury, neurotrophic factors (NFs) are synthesised by non-neuronal (Schwann cells and fibroblasts) in the nerve trunk, and act to support the outgrowth of axons. NFs can be classified into three major groups: (1) neurotrophins; (2) neurokines; and (3) the transforming growth factor beta (TGF)-beta superfamily.

Watershed-based segmentation of cell nuclei boundaries in Pap smear images

In this work we present a fully automated method for the accurate detection of cell nuclei boundaries in conventional Pap smear images, based on the watershed transform. For the extraction of nuclei and cytoplasm markers, which are used as starting points for the flooding process, a morphological reconstruction step is initially performed in each image. The watershed transform is then applied in the color morphological gradient image, which shows the boundaries of the more pronounced nuclei. For the elimination of false positive findings, salient features of shape and intensity of the detected regions were calculated and a clustering step is performed. The method was evaluated with a data set of 19 images containing 3616 recognized cells nuclei. The performance of the method was evaluated in terms of the correct detection of the positions of the nuclei. Comparisons with the segmentation results of the gradient vector flow (GVF) deformable model showed that the segmentation of the watershed transform captures more accurately the boundaries of nuclei, leading to a better performance of the clustering algorithm.

Cellular neurilemoma (Schwannoma) of the descending colon mimicking carcinoma : Report of a case

We report a rare case of a cellular neurilemoma (schwannoma) of the descending colon, mimicking carcinoma, not accompanied by von Recklinghausens disease. The differential diagnostic problems are discussed and the possibility of a site-specific, modified Schwann cell of myenteric plexus origin is suggested.

External beam irradiation in angioplasted arteries of hypercholesterolemic rabbits: The dose and time effect

PURPOSE To study the dose and time effect of external beam irradiation on the morphometry of both angioplasted and nonangioplasted arteries in a hypercholesterolemic rabbit model. METHODS AND MATERIALS Eight groups of rabbit femoral arteries were studied: arteries (a) with no intervention, (b) irradiated with a 12-Gy 6 MV X-ray dose, (c) with a 18-Gy, (d) treated with balloon angioplasty, (e) dosed with 12-Gy half an hour post-angioplasty, (f) dosed with 18-Gy half an hour post-angioplasty, (g) dosed with 12-Gy 48 h post angioplasty, (g) dosed with 18-Gy 48 h post angioplasty. RESULTS External irradiation at either 12 or 18 Gy was not found to change vessel morphometry in noninjured arteries. The 12-Gy dose given soon after angioplasty further increased percentage stenosis (63% on the average), despite the preservation of the lumen cross-sectional area. Positive remodeling was not observed in arteries given 18-Gy half an hour post angioplasty to counterbalance the increased neointimal formation. Therefore, this treatment resulted in a drastic reduction in lumen area and in enhancement of percentage stenosis (84% on the average). On the contrary, the delayed irradiation of the angioplasted arteries at either 12 or 18 Gy was not found to influence any of the studied morphometric parameters 5 weeks after angioplasty. CONCLUSIONS Uniform external beam irradiation up to 18 Gy was well tolerated by intact femoral arteries. Prompt 12- or 18-Gy irradiations accentuated percentage stenosis. However the lumen cross-sectional area was preserved only at the lower dose point. Delayed irradiation at any dose did not influence the restenosis process.

Appendicectomies in Albanians in Greece: outcomes in a highly mobile immigrant patient population

BackgroundAlbanian immigrants in Greece comprise a highly mobile population with unknown health care profile. We aimed to assess whether these immigrants were more or less likely to undergo laparotomy for suspected appendicitis with negative findings (negative appendicectomy), by performing a controlled study with individual (1:4) matching. We used data from 6 hospitals in the Greek prefecture of Epirus that is bordering Albania.ResultsAmong a total of 2027 non-incidental appendicectomies for suspected appendicitis performed in 1994-1999, 30 patients with Albanian names were matched (for age, sex, time of operation and hospital) to 120 patients with Greek names. The odds for a negative appendicectomy were 3.4-fold higher (95% confidence interval [CI], 1.24-9.31, p = 0.02) in Albanian immigrants than in matched Greek-name subjects. The difference was most prominent in men (odds ratio 20.0, 95% CI, 1.41-285, p = 0.02) while it was not formally significant in women (odds ratio 1.56, 95% CI, 0.44-5.48). The odds for perforation were 1.25-fold higher in Albanian-name immigrants than in Greek-name patients (95% CI 0.44- 3.57).ConclusionsAlbanian immigrants in Greece are at high risk for negative appendicectomies. Socioeconomic, cultural and language parameters underlying health care inequalities in highly mobile immigrant populations need better study.

Automated Detection of Cell Nuclei in PAP stained cervical smear images using Fuzzy Clustering

In this work we present an automated method for cell nuclei detection in PAP stained cervical smear images. The method is based on the detection of regional minima in the image, followed by a two phase clustering of the detected centroids. An empirical rule and the fuzzy C-means clustering algorithm are applied on the resulted centroids in order to reduce false positive findings. The number of classes in which the nuclei are classified is determined automatically for the dataset that is used. The proposed method is evaluated using cytological images of conventional PAP stained cervical smears, which contain 3085 recognized squamous epithelial cells.

Decreased DNA Disruption in the Porcine Neocortex with Erythromycin Preconditioning during Prolonged Hypothermic Circulatory Arrest: Evidence for Neuroprotection

We have previously reported that the neocortex is selectively vulnerable to injury in an acute porcine model of hypothermic circulatory arrest (HCA) at 18°C. In view of recent evidence showing that pharmacologic preconditioning with a single dose of erythromycin induces tolerance against transient global cerebral ischemia in rats, we hypothesized that erythromycin would reduce the number of apoptotic neurons in the neocortex in an acute porcine model of HCA at 18°C.