Segmentation of epidermal tissue with histopathological damage in images of haematoxylin and eosin stained human skin.

Background: Digital image analysis has the potential to address issues surrounding traditional histological techniques including a lack of objectivity and high variability, through the application of quantitative analysis. A key initial step in image analysis is the identification of regions of interest. A widely applied methodology is that of segmentation. This paper proposes the application of image analysis techniques to segment skin tissue with varying degrees of histopathological damage. The segmentation of human tissue is challenging as a consequence of the complexity of the tissue structures and inconsistencies in tissue preparation, hence there is a need for a new robust method with the capability to handle the additional challenges materialising from histopathological damage.Methods: A new algorithm has been developed which combines enhanced colour information, created following a transformation to the L*a*b* colourspace, with general image intensity information. A colour normalisation step is included to enhance the algorithm's robustness to variations in the lighting and staining of the input images. The resulting optimised image is subjected to thresholding and the segmentation is fine-tuned using a combination of morphological processing and object classification rules. The segmentation algorithm was tested on 40 digital images of haematoxylin & eosin (H&E) stained skin biopsies. Accuracy, sensitivity and specificity of the algorithmic procedure were assessed through the comparison of the proposed methodology against manual methods.Results: Experimental results show the proposed fully automated methodology segments the epidermis with a mean specificity of 97.7%, a mean sensitivity of 89.4% and a mean accuracy of 96.5%. When a simple user interaction step is included, the specificity increases to 98.0%, the sensitivity to 91.0% and the accuracy to 96.8%. The algorithm segments effectively for different severities of tissue damage.Conclusions: Epidermal segmentation is a crucial first step in a range of applications including melanoma detection and the assessment of histopathological damage in skin. The proposed methodology is able to segment the epidermis with different levels of histological damage. The basic method framework could be applied to segmentation of other epithelial tissues

Fractal dimension of chromatin is an independent prognostic factor for survival in melanoma

<p>Abstract</p> <p>Background</p> <p>Prognostic factors in malignant melanoma are currently based on clinical data and morphologic examination. Other prognostic features, however, which are not yet used in daily practice, might add important information and thus improve prognosis, treatment, and survival. Therefore a search for new markers is desirable. Previous studies have demonstrated that fractal characteristics of nuclear chromatin are of prognostic importance in neoplasias. We have therefore investigated whether the fractal dimension of nuclear chromatin measured in routine histological preparations of malignant melanomas could be a prognostic factor for survival.</p> <p>Methods</p> <p>We examined 71 primary superficial spreading cutaneous melanoma specimens (thickness ≥ 1 mm) from patients with a minimum follow up of 5 years. Nuclear area, form factor and fractal dimension of chromatin texture were obtained from digitalized images of hematoxylin-eosin stained tissue micro array sections. Clark's level, tumor thickness and mitotic rate were also determined.</p> <p>Results</p> <p>The median follow-up was 104 months. Tumor thickness, Clark's level, mitotic rate, nuclear area and fractal dimension were significant risk factors in univariate Cox regressions. In the multivariate Cox regression, stratified for the presence or absence of metastases at diagnosis, only the Clark level and fractal dimension of the nuclear chromatin were included as independent prognostic factors in the final regression model.</p> <p>Conclusion</p> <p>In general, a more aggressive behaviour is usually found in genetically unstable neoplasias with a higher number of genetic or epigenetic changes, which on the other hand, provoke a more complex chromatin rearrangement. The increased nuclear fractal dimension found in the more aggressive melanomas is the mathematical equivalent of a higher complexity of the chromatin architecture. So, there is strong evidence that the fractal dimension of the nuclear chromatin texture is a new and promising variable in prognostic models of malignant melanomas.</p

Fractal Characteristics of May-Grünwald-Giemsa Stained Chromatin Are Independent Prognostic Factors for Survival in Multiple Myeloma

The use of computerized image analysis for the study of nuclear texture features has provided important prognostic information for several neoplasias. Recently fractal characteristics of the chromatin structure in routinely stained smears have shown to be independent prognostic factors in acute leukemia. In the present study we investigated the influence of the fractal dimension (FD) of chromatin on survival of patients with multiple myeloma.We analyzed 67 newly diagnosed patients from our Institution treated in the Brazilian Multiple Myeloma Study Group. Diagnostic work-up consisted of peripheral blood counts, bone marrow cytology, bone radiograms, serum biochemistry and cytogenetics. The International Staging System (ISS) was used. In every patient, at least 40 digital nuclear images from diagnostic May-Grünwald-Giemsa stained bone marrow smears were acquired and transformed into pseudo-3D images. FD was determined by the Minkowski-Bouligand method extended to three dimensions. Goodness-of-fit of FD was estimated by the R(2) values in the log-log plots. The influence of diagnostic features on overall survival was analyzed in Cox regressions. Patients that underwent autologous bone marrow transplantation were censored at the day of transplantation.Median age was 56 years. According to ISS, 14% of the patients were stage I, 39% were stage II and 47% were stage III. Additional features of a bad prognosis were observed in 46% of the cases. When stratifying for ISS, both FD and its goodness-of-fit were significant prognostic factors in univariate analyses. Patients with higher FD values or lower goodness-of-fit showed a worse outcome. In the multivariate Cox-regression, FD, R(2), and ISS stage entered the final model, which showed to be stable in a bootstrap resampling study.Fractal characteristics of the chromatin texture in routine cytological preparations revealed relevant prognostic information in patients with multiple myeloma

Resistance of bull spermrztozoa to low temperatures : observations on variability of ejaculates behaviour

L'étude porte sur 20 éjaculats fournis par 20 taureaux différents. A partir de chaque éj acula t dilué, 8 groupes de doses de semence (paillettes de 0,25 ml) sont constituées. A l'exception du groupe 1 dont les paillettes sont maintenues à + 5° C, les paillettes de chacun des 7 autres groupes sont, dans un premier temps, refroidies ensemble dans les vapeurs d'azote liquide jusqu'à ce que la température de la semence (contrôlée au thermo couple électrique) atteigne : groupe 2, — 20° C ; groupe 3, — 30" C ; groupe 4, — 50° C ; groupe 5, — 70° C ; groupe 6, — 80° C ; groupe 7, — 120° C ; groupe 8 (témoin), — 163° C (température des vapeurs d'azote liquide). Dans un deuxième temps, chacun de ces 8 groupes de paillettes est immergé dans l'azote liquide aussitôt que les températures précitées sont obtenues. On constate que le pourcentage maximal de spermatozoïdes vivants que l'on peut attendre de chaque éjaculat, lors du dégel, est obtenu à une température supérieure à — 163° C. Cette température n'est pas la même pour tous les éjaculats. Le pourcentage de survie (moyenne des 20 éjaculats) à l'issue de la congélation en deux temps varie avec la température finale du premier temps : 0 p. 100 (groupe 1) ; 40,57 p. 100 (groupe 2) ; 52,78 p. 100 (groupe 3) ; 56,15 p. 100 (groupe 4) ; 61,90 p. 100 (groupe 5) ; 66,60 p. 100 (groupes 6, 7, 8). Ces résultats font ressortir la variabilité du comportement des éjaculats aux basses températures. Ils montrent aussi que la congélation du sperme de taureau peut être consi dérée comme effective pour tous les éjaculats dès que la température de la semence atteint — 80° C.From each of 20 diluted ejaculates, 8 groups of 0,25 ml straws were frozen, according to the following scheme: group 1, direct immersion into liquid nitrogen; group 2 to group 8: immersion into liquid nitrogen imme diately after being frozen into liquid nitrogen vapor until seminal tempe ratures reached: — 20° C (group 2); — 30° C (group 3); — 50° C (group 4); — 70° C (group 5) ; — 80° C (group 6) ; — 120° C (group 7) ; — 163° C (group 8, control). The maximal sperm survival expected from a given ejaculate is obtained at a temperature which lies between 0 and — 160° C and this intermediate temperature is not the same for all ejaculates. Mean sperm survival at thawing (7 seconds at + 30° C) were: 0 p. 100 (group 1); 40.57 p. 100 (group 2); 52.78 p. 100 (group 3); 56.15 p. 100 (group 4); 61.90 p. 100 (group 5); 66.60 p. 100 (groups 6, 7, 8). The number of ejaculates showing at least an optimal 65 p. 100 sperm survival was 2 (or 10 p. 100), 3 (or 10 p. 100), 10 (or 50 p. 100), 12 (or 60 p. 100) and 18 (or 90 p. 100) when immersion into liquid nitrogen occured as seminal temperatures reached respectively — 20; — 30; — 50; — 70; — 80° C (and below). These results point out a wide variability of the behaviour of ejaculates at low temperatures and confirm that freezing must be considered as complete for any ejaculate as soon as seminal temperature inside the straw reaches — 80° C

Refroidissement de +32°c a +5°c de sperme dilue de taureau de race borgou au benin

Trois temps (30,60 et 120 minutes) de refroidissement (de + 32°C à + 5°C) de semences de taureau de race Borgou au Bénin ont été comparés. Les éjaculats ont été initialement dilués avec le dilueur citrate de sodium/jaune d’oeuf, additionné ou non de fructose et de glycérol. Les différences de longévité entre les trois temps de refroidissement ne sont pas significatives (P>0.05). L’addition de fructose et de glycérol au dilueur n’a pas augmenté la longévité des spermatozoïdes. Pour desraisons pratiques, le refroidissement en 60 minutes de la semence diluée permet de mieux organiser les manipulations des semences dans un centre d’insémination artificielle dans les conditions de celle du Bénin. Cooling (+ 32 °C to + 5 °C) on three times (30, 60 and 120 minutes) of Borgou bull semen have been compared. Ejaculate was initially extended with citrate/sodium egg yolk added or not with fructose and glycerol. Differences of longevity between the three times of cooling are not significant (P>0.05). The addition of fructose and glycerol to the extender (egg - yolk) has not increased the longevity of the spermatozoa. For practice reasons, the cooling in 60 minutes of the diluted semenallows better organization and manipulation at artificial insemination center in Benin