Search results for " endothelium"
showing 10 items of 63 documents
Granulometric analysis of corneal endothelium specular images by using a germ–grain model
2007
Specular microscopy is widely used to study the human corneal endothelium status in vivo. In this paper, the corneal endothelium is represented as a binary image composed of the cell inscribed circles. The granulometric distribution function of the complement of this image is used as a functional descriptor, which provides information about the shape, size and spatial arrangement of cells. Experimental evaluation using bootstrap techniques shows its ability to discriminate between controls and pathological cases. It represents a reliable and graphical alternative to the classical indices (cell density, hexagonality and coefficient of variation of cell areas), which behave poorly when detect…
Corneal Oxygen Supply Conditions
1976
Pronounced cornea hypoxia induces swelling and a loss of transparency. Hypoxia of longer duration causes necrosis, particularly of the corneal endothelium. These findings were observed after ligation of the cilial arteries and the arteria carotis interna, after reduction of oxygen tension on the anterior corneal surface as well as after prolonged wearing of ill-fitted contact lenses (11, 15, 18, 22, 23). Because the normal function of the corneal endothelium plays a central role in maintaining transparency, an insufficient endothelial oxygen supply can directly influence vision (3, 17).
MORPHOMETRIC ANALYSIS OF HUMAN CORNEAL ENDOTHELIUM BY MEANS OF SPATIAL POINT PATTERNS
2002
This paper presents a method for detecting abnormalities in spatial arrangements of cells within any tissue that can be described by different sets of relevant points. The method has been applied to the detection of subtle abnormalities in corneal endothelia. Images of this type of tissue can be characterized by two types of points: cell centroids and triple points associated with the apical intersections as it was proposed by Díaz.7 Both types of points jointly considered are modeled using a bivariate spatial point process; then a statistical analysis based on certain distributional descriptors proposed by Doguwa4,9 is carried out to discriminate severe and subtle abnormalities from contr…
A granulometric analysis of specular microscopy images of human corneal endothelia
2005
The inner layer of the human cornea, called the corneal endothelium, plays an important role in the maintenance of corneal transparency. Specular microscopy is the most widely used technique to study the corneal endothelium in vivo. Improvements in technology have allowed us to obtain good quality specular images, but the detection and quantification of small size-shape cell changes is not obvious, specially when the physician wants to evaluate endothelial cell changes after some surgical procedures. This paper proposes a methodology to analyze specular microscopy images. Every corneal endothelium is described by means of different cumulative distribution functions or some moments (mean, st…
Measuring the Spatial Homogeneity in Corneal Endotheliums by Means of a Randomization Test
1999
Quantification of regularity of cell sizes and the spatial arrangement of cells in corneal endotheliums becomes of a great importance associated to stress situations such as cataract surgery, corneal transplantation or implantation of intra-ocular lenses. A new index of regularity of the spatial distribution of cell sizes in corneal endotheliums is proposed. The corneal endothelium is described by means of a spatial marked point pattern (the cell centroids marked with the cell areas). The hypothesis of no dependency between mark and locations is tested by a Monte Carlo test. The new index is the p-value of the test validating the hypothesis. Pairs of endotheliums from different eyes of the …
Classifying human endothelial cells based on individual granulometric size distributions
2002
Abstract This paper presents an application to a medical problem of methods of shape analysis based on mathematical morphology. The medical problem consists on the detection of abnormalities in the corneal endothelium, a tissue composed by quasi-planar cells of ideally regular hexagonal shape. Images of this tissue are taken by a specular microscope and used to evaluate the corneal endothelium status. Up to now, cell density, hexagonality and an analysis of cell areas are the usual descriptors of a corneal endothelium. These parameters are not sensitive enough to detect subtle lesions. What this paper proposes is an analysis based on granulometries, which are size-shape descriptors widely u…
Set Descriptors for Visual Evaluation of Human Corneal Endothelia
2001
Images of corneal endothelium obtained from specular microscopy are of great importance in the evaluation of the corneal endothelium status. Several commercial tools provide some numerical descriptors to characterize these images in terms of cell density, hexagonality, and some descriptive statistics of the cell areas. However, it is a too simple analysis that only detects severe abnormal endothelia with many irregular and large cells. Detection of subtle abnormalities needs a more refined analysis. This paper proposes a shape-size descriptor based on some modified versions of the geometric covariogram. This descriptor is presented as a valid alternative to the classical analysis that provi…
Bazedoxifene increases the proliferation of human arterial endothelial cells but does not affect the expression of cyclins A, B, and D1 and of p27Kip1
2021
Endothelial dysfunction and denudation are considered a first step in atherosclerosis. Endothelial proliferation is key for cellular repair. The effect of bazedoxifene on the vascular endothelium h...
Lymphatic endothelial progenitors bud from the cardinal vein and intersomitic vessels in mammalian embryos.
2012
Abstract The lymphatic vasculature preserves tissue fluid balance by absorbing fluid and macromolecules and transporting them to the blood vessels for circulation. The stepwise process leading to the formation of the mammalian lymphatic vasculature starts by the expression of the gene Prox1 in a subpopulation of blood endothelial cells (BECs) on the cardinal vein (CV) at approximately E9.5. These Prox1-expressing lymphatic endothelial cells (LECs) will exit the CV to form lymph sacs, primitive structures from which the entire lymphatic network is derived. Until now, no conclusive information was available regarding the cellular processes by which these LEC progenitors exit the CV without co…
Expression Profile of Endoglin in Different Grades of Endometrial Cancer
2019
Background Endoglin is a marker of active, proliferating endothelial cells of blood vessels. In many cancers, it is present in both peripheral vessels and vessels located inside the tumor. Endoglin is more specific and sensitive compared to other tumor angiogenesis markers. It is suggested that endoglin can be considered a reliable marker of disease outcome. Objective The aim of the study was to assess the expression of endoglin and to determine its potential usefulness as a complementary molecular marker of endometrial cancer. Method The study included 60 women who underwent hysterectomy: 45 with endometrioid endometrial cancer (study group) and 15 without neoplastic changes (control group…