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PubMedDate not supplied

[Role of free radical oxidation in the pathogenesis of acute hepatic necrosis in visceral-ischemic shock].

The mechanisms responsible for necrotic damage to liver cells at the stages of experimental visceral-ischemic shock were studied by computerized morphometric techniques for interphasic nuclei of hepatocytes. A number of geometric, optical, and textural parameters of the structure of chromatin have been defined, which characterize the extent of its damage as shock progresses. The increment of degenerative signs of the nuclear structures occurred concurrently with the enhancement of free radical processes, which may be indicative of the fact that there is their pathophysiological relationship. The findings were comparable with those of a multiparametric analysis of chromatin in the isolated hepatocytes exposed to free radical oxidation. The coincidence of temporal and structural parameters of hepatocytic nuclear alteration in shock and in the model system makes the authors conclude that in visceral-ischemic shock a great role in the genesis of cytolysis is played by the generation of active oxygen forms and their direct or lipid peroxidation-mediated action on the nuclear structures.

Computer Simulation↗
PubMed1994

Morphometric X-ray absorptiometry of the spine: correlation in vivo with morphometric radiography. Study of Osteoporotic Fractures Research Group.

The diagnosis of vertebral fractures has been based on lateral thoracic and lumbar spine films and entails the determination of crush, endplate and wedge deformities of the vertebral bodies, generally between T4 and L4. Accuracy and precision of X-ray based morphometry are limited by geometric distortion and other technique-related factors. This paper proposes the use of morphometric X-ray absorptiometry (MXA) as a method which overcomes many of the limitations of morphometric radiography. MXA generates paired anteroposterior and lateral images of the spine using a scanning fan beam geometry that significantly reduces distortions inherent in the cone beam geometry used in conventional X-rays. Intra-observer precision of MXA on 41 subjects aged 65 years and older was 1 mm for vertebral height assessments and 4.7% for vertebral wedge parameters. Linear correlation with vertebral heights and wedge parameters on 32 subjects evaluated by both MXA and morphometric radiography demonstrated a root of the mean squared error of 2.1-2.4 mm and 7.0%, respectively. Vertebral deformities could be identified by MXA. The study documents the feasibility of MXA for the assessment of vertebral deformities. However, further investigation is needed to document the ability of MXA to diagnose prevalent and incident fractures.

Absorptiometry, Photon↗
PubMedDate not supplied

A geometric model for measurement of surface distance, surface area, and volume from tomographic images.

Surface area and volume are essential measurements in the morphometric assessment of anatomical structures. New algorithms were developed to measure (1) distance along a curve, (2) surface area, and (3) volume using data extracted from tomographic images as a geometrical surface model. The model is a list of coordinates and normal vectors for each voxel or point gathered from the surface of a selected object. The resulting surface-based pointlist is also used for high-speed rendering of surfaces. Differential arclength and surface area are measured with high numeric precision by using the absolute value of the maximum component of the unit normal vector (MUNC) to approximate their values. These differential values are summed to measure distance along a curve and surface area. A discrete form of the Divergence theorem, also using the MUNC, is used to calculate volume. The intrinsic accuracy of the measurement algorithms was evaluated using computer generated pointlists of circles, ellipses, spheres, and ellipsoids. Compared to standard measurement techniques, the new algorithms provided the greatest accuracy and least shape-related bias for measurement of distance, surface area, and volume. Feasibility of using the new algorithms to measure physical objects was tested with CT images of spherical, egg-shaped, and irregular shaped objects. The Dividing Cubes algorithm was used to segment and create pointlists from the CT data. Volume and surface area measurements from CT data compared extremely well with reference values for most objects tested (errors less than 2%).

Algorithms↗
PubMed1981

Texture of white blood cells expressed by the counting densitogram.

The counting of particles and holes in white blood cells during thresholding at different gray levels results in a histogram, the counting densitogram, which contains information about granularity. Parameters describing the shape of this histogram appear to be sufficiently characteristic for the five normal white blood cell classes to allow a 84% correct discrimination between them. This method to quantitate granularity could be valuable for the analysis of cell texture and therefore, when used in combination with geometrical and density histogram parameters, could contribute to the results of morphometric discrimination between other than normal white blood cells.

Basophils↗
PubMed2002

Atherosclerosis and flow in carotid arteries with authentic geometries.

The influence of blood flow on the depositions and development of atherosclerotic lesions have been observed and described since the 19th century. Observations have shown that depositions correlate with regions of low wall shear stress. However, the exact correlations between depositions, vessel geometry and flow parameters are not yet known. The purpose of this study was the quantification of atherosclerosis risk factors in carotid bifurcation. This artery has attracted particular interest because lesions are often found in this bifurcation. Post mortem, the arteries are excised and vessel casts are produced. Afterwards, the arteries are analyzed morphometrically. The vessel casts are used for the assessment of some geometrical parameters. 31 carotid bifurcations were analyzed in this study. Eight vessel casts were digitized and rendered three-dimensional mathematical models of the arteries. These data were imported by the computational fluid dynamics program FLUENT. Further, the blood flow was reconstructed in a computer model based on the individual vessel geometry. The flow parameters, such as velocity, pressure and wall shear stress were computed. At the same time the geometrical parameters and wall alterations are known. This permits the comparison of the anatomical shape and its flow with the distribution and level of the wall alterations.

Adult↗
PubMed1996

Quantitative clinical anatomy of the human cornea in vivo. A morphometric study by ultrasonic pachymetry and computer-assisted topographic videokeratoscopy.

The cornea is the most important refractive element in the human ocular system, providing approximately two thirds of the eye's refractive power in the nonaccommodative state. The methods of description and analysis of the corneal anatomy in vivo continue to be refined thanks to the increased interest aroused by the advent of corneal refractive surgery, which aims to modify the dioptric power of the ocular system by altering the thickness and the radius of curvature of the cornea. In the present study we report quantitative morphometric data of corneal thickness and the radius of curvature of the anterior surface of the cornea obtained in vivo from normal human subjects using ultrasonic pachymetry and computer-assisted topographic videokeratoscopy. We found a highly significant statistical correlation in the distribution of corneal thickness and the radius of curvature of the anterior surface of the cornea along the principal corneal meridians (horizontal and vertical meridians) and within three different concentric zones of the cornea, 2, 4 and 6 mm, respectively, from the geometric center along the principal meridians. Correlation was also found for the same morphometric parameters between the right and the left eye. By contrast, no correlation was found between corneal thickness and the radius of curvature of the anterior surface of the cornea. These findings suggest that the adult human cornea is a structure characterized by a highly ordered tridimensional architecture and symmetry and that a specific distribution of corneal thickness and the radius of curvature of the anterior corneal surface along the principal meridians may be essential for the refractive function of the human corneal diopter in vivo.

Adult↗
PubMed1990

Image analysis of Nissl-stained neuronal perikarya in the primary visual cortex of the rat: automatic detection and segmentation of neuronal profiles with nuclei and nucleoli.

An image analysing procedure for the morphometric characterization of cortical neurons in Nissl-stained brain sections is described. It consists of the automatic detection of cellular profiles and their compartments: cytoplasm, nucleus and nucleolus. The algorithm was designed to cope with the large morphological spectrum of cortical perikarya (e.g. geometrical properties of perikarya, staining intensities of cell compartments and nucleo-plasmic area-ratio) including pyramidal (Golgi-category I) and non-pyramidal (Golgi-category II) neurons. Clusters of cells were separated and non-neuronal structures (e.g. glia, endothelial cells) as well as tangential, non-nucleolated sections through neuronal perikarya recognized and excluded from further analysis without requiring interactive procedures. The performance of the profile recognition procedure was evaluated using 426 nucleolated and non-nucleolated profiles of different types of neurons in the primary visual cortex of the rat. Nucleolated profiles were recognized as such with a 91% accuracy, non-nucleolated profiles were rejected correctly in 90% of cases. After automatic segmentation and selection of nucleolated neuronal profiles from the microscopic field, a large set of quantitative morphological features including geometrical, densitometrical and textural parameters can be measured using high power light microscopy. This permits quantitative morphometric characterization of different neuronal types. This procedure is the first part of a system for the automatic classification of Nissl-stained cortical neurons.

Algorithms↗
PubMed1981

A computer system for combined neuronal mapping and morphometry.

A computer system has been developed which allows both mapping and planimetry of histological preparations. Data consist of cytoarchitectonic boundaries defined in low-power micrographs of thick sections, and nuclear and vascular profiles defined in high-power micrographs of semi-thin sections taken from the original thick tissue, and landmarks common to both. Data from these different preparations and magnifications are entered into the computer on a digitizing tablet and are stored as points in a real-world coordinate system, along with profile labels, landmarks for alignment purposes, and section depth. Subsequent programs determine parameters such as area and perimeter for each profile, as well as its geometric center and relationship to the cytoarchitectonic boundary. This mapping parameter allows morphometric analysis of profiles as a function of their position. Other programs allow display and manipulation of data in 3 dimensions, cell counts, and stereology. Data acquisition is done in the laboratory, using a micro-computer; analysis and display are done on a large time-sharing computer connected to the small machine by a telephone interface.

Animals↗
PubMed2006

Computerized morphometry of mean nuclear diameter and nuclear roundness in canine mammary gland tumors on cytologic smears.

BACKGROUND: The use of computer-based image analysis systems in veterinary oncology has increased. Computerized morphometry is a part of image analysis that describes geometric figures of cellular structures in any dimension. Most investigators have performed morphometric analysis on histologic specimens. Computer-assisted nuclear cytomorphometry can provide important preoperative information on neoplastic lesions in animals. OBJECTIVES: The aim of this study was to define whether the morphometric parameters of mean nuclear diameter and nuclear roundness could be used to differentiate benign from malignant canine mammary gland tumors on cytologic specimens. METHODS: Mean nuclear diameter and nuclear roundness were determined by computer-assisted morphometry of epithelial cells in Hemacolor-stained cytologic smears from normal canine mammary gland (n = 7) and from canine mammary adenomas (n = 8), tubulopapillary carcinomas (n = 9), and solid carcinomas (n = 6). Data were analyzed by the Mann-Whitney U test. RESULTS: Significant differences (P <.001) were found in mean nuclear diameter and nuclear roundness among all tumor types and in comparison with normal canine mammary gland epithelial cells (except for nuclear roundness between tubulopapillary carcinomas and solid carcinomas). CONCLUSIONS: The morphometric parameters of mean nuclear diameter and nuclear roundness can be used in the preoperative differentiation of benign from malignant canine mammary gland tumors.

Animals↗
PubMed1975

Morphometric estimation of brain swelling and atrophy.

A morphometric method was presented to estimate brain swelling or atrophy from the geometric characteristics of the pontine cross section. The ratio of the area (A) to the perimeter squared (L2) was termed "area factor" (f) and used as a factor indicating circularity. Normal standards for the net cross-sectional area (Ap) and the area factor (f) of the pons measured on paraffin sections were 3.43 approximately 4.87 cm2 and 0.0684 approximately 0.0740, respectively. Values exceeding these ranges suggested brain edema. The pontine area factors (f) of the control cases under 60 years of age were less spread out than Ap, whereas they exhibited larger individual variations over that age presumably as a result of varying involution of the brain. A close correlation was found between Ap and water content of the cerebral white matter, except in pontine hemorrhage. The correlation was particularly marked in the group of cerebral diseases other than stroke. The longitudinal length of the basis pontis (lp) was essentially the same in the normal brain and even in the stoke group excluding pontine and cerebellar hemorrhage. In severe brain swelling the pontine longitudinal length was rather reduced.

Adult↗
PubMed1984

Partitioning of paracellular conductance along the ileal crypt-villus axis: a hypothesis based on structural analysis with detailed consideration of tight junction structure-function relationships.

Current models of intestinal transport suggest cells which absorb ions are located on the villus while secretory cells are located in the crypt and putatively have paracellular pathways which are highly conductive to Na+. One approach to assess possible variation in small intestinal paracellular conductance along the crypt-villus axis is to morphometrically analyze the structural aspects of crypt and villus tight junctions (TJs) which relate to paracellular resistance. Such detailed analysis of junctional structure in this heterogeneous epithelium would permit one to compare intestinal TJ structure-function relationships with those in a structurally simpler epithelium such as that of toad urinary bladder. This comparison would also be of considerable interest since previous similar comparisons have failed to consider in detail the geometric dissimilarity between these two epithelia. We applied light, electron microscopic, and freeze-fracture morphometric techniques to guinea pig ileal mucosa to quantitatively assess, for both crypts and villi, linear TJ density, relative surface contributions, and TJ strand counts. Mean linear TJ densities were 76.8 m/cm2 for crypt cells and 21.8 m/cm2 for villus absorptive cells. Mean TJ strand counts were 4.45 for undifferentiated crypt cell TJs and 6.03 for villus absorptive cell TJs. The villus constituted 87% and the crypt 13% of total surface. We utilized these data to predict paracellular conductance of crypts vs. villi based on equations derived from those of Claude (P. Claude, J. Membrane Biol. 39:219-232, 1978). Such analysis predicts that 73% of ileal paracellular conductance is attributable to the crypt. Furthermore, we obtained literature values for paracellular resistance in mammalian ileum and toad urinary bladder and for toad bladder TJ structure and linear density and constructed a relationship which would allow us to more accurately compare TJ structure-function correlates between these two epithelia. Such a comparison, which considers both surface amplification and TJ structure and distribution in these epithelia, shows that one would predict in vitro measured values for paracellular resistance should be approximately two orders of magnitude less in mammalian ileum than in toad urinary bladder. This predicted discrepancy (115-fold) correlates well with the observed difference (100-fold).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Detection of length-dependent effects of tandem repeat alleles by 3-D geometric decomposition of craniofacial variation.

Topologically conservative morphological transformations typify the succession of species in the fossil record and also typify more subtle morphological variation within species. Isolation and quantification of morphological variation along its various intermingled modes becomes increasingly difficult as the structures under consideration increase in complexity. Here, we describe a comparative morphometric and genomic study in dogs in which complex three-dimensional craniofacial variation is mathematically distilled into simpler geometric components to test the hypothesis that incremental mutations at developmental loci result in simple geometric deformations of morphology. Combinations of candidate transforms are computationally evaluated for their ability to accurately transform a reference three-dimensional skull model into those of distinct breeds. A set of five simple basis functions are found to be sufficient to describe most craniofacial variation among dogs. Allele lengths of amino acid repeat length variants in developmental regulator genes, which frequently have quantitative effects on phenotype, were compared to geometric terms using Pearson correlation and regression. The coordinated quantitative representation of both phenotype and genotype improves the statistical power for the detection of causative genotype-phenotype relationships and enabled the characterization of the influence of Runx-2 coding repeat length on craniofacial variation among domestic dogs.

Animals↗
PubMed2005

Stereological study of postnatal development in the mouse utricular macula.

This study describes the morphometric changes taking place in the utricular macula of mice with ages in geometric progression from 1 to 512 days after birth. By using design-based stereological methods, the total volume and surface area of the sensory epithelium as well the total number of the hair cells and supporting cells were estimated. Finally, the numerical density, volume density, and mean volume of the individual cell types were determined. The major changes were found in the number of the individual cell types during the first couple of weeks, and a mature composition of cell types was not attained until 16 days after birth. There was no change in the total number of cells and no decline in the number of hair cells within the time period studied.

Acoustic Maculae↗
PubMed1989

Atherometric system: morphometric standardized methodology to study atherosclerosis and its consequences.

A group of strong mutual dependent variables, obtained by measuring some morphological and pathomorphological characteristics of an artery affected by atherosclerosis (arterial variables) and its organ-related damage (organ-related variables DRV), yield a suitable methodology to study and characterize this disease and its further severe consequences. Applying some biophysical (rheological, geometrical, and haemodynamical) and mathematical reasonings to those measurements an atherometric system AS is derived. It is a new standardized morphometric methodology which allows, by the use of their variables, the development of useful pathomorphological, pathogenetical, statistical, and epidemiological investigations. The variables of the AS are divided into 1. descriptives and 2. weighting indices WI to estimate the severity of atherosclerosis. The descriptive arterial variables were obtained from each type of atherosclerotic lesion AL, fatty streak, fibrous plaque, and severe (complicated and calcified) plaques, latter normalize and further represented in a 3-dimensional vector, in order to conserve all the analytical information of each type of AL. Their WI are obstruction, stenosis, and benignity. The descriptives DRV (estimated volumes) and their respectively derived WI, are in relation with the pathological conditions: fibrosis, necrosis, haemoŕrhage, total damage, and their counterpart non-affected (sufficient) variables. A digitizer coupled to a personal computer LTEL (Cuba) to obtain the primary data was used. All data were processed in a computer EC-1040 (G.D.R.) using the statistical commercial package "SPSS" for scientific analysis.

Aorta, Abdominal↗
PubMed1989

Effect of swimming on bone growth and development in young rats.

The effect of chronic swimming on bone modelling was studied. Forty female Sabra rats (5 weeks old) were randomly assigned to the following experimental groups: 30 rats were trained to swim (water bath 35 +/- 1 degree C, one h daily, five times a week) for 20 weeks--20 of them loaded with lead weights (1% body weight) while the rest (10 animals) swam load free. Ten sedentary rats matched for age and weight served as controls. At the end of the twenty-week swimming period, all rats were sacrificed, both humeri bones were dissected and prepared for the following examinations: morphometric, bone density (BD), bone mineral content (BMC), compression tests and cross-sectional geometrical parameters, histomorphometry and biochemical analysis of minerals (Ca, Pi, Mg, Zn). All measured parameters were found to be significantly higher (P less than 0.05) in the swimming rats irrespective of load, as compared with the controls. Bone weight was higher by 19%, bone volume by 11%, bone length by 2.8%, cortical area by 16%, BD by 7% and BMC by 15%. The compression breaking force at the distal shaft of the humerus was higher by 24% in the trained group, while the ultimate compressive stress was not significantly different. Maximal and minimal moment of inertia at the distal diaphysis were 33.4 and 40% higher, respectively, for the swimming groups than the controls. Ca, Pi, Mg and Zn levels per total humeral bone were significantly higher in the exercising rats. The histomorphometry and cross-sectional data emphasize longitudinal and transversal growth. These data indicate that swimming exercise exerts a positive effect on bone growth and development in young rats.

Animals↗
PubMed1997

Red cell distortion and conceptual basis of diffusing capacity estimates: finite element analysis.

To understand the effects of dynamic shape distortion of red blood cells (RBCs) as it develops under high-flow conditions on the standard physiological and morphometric methods of estimating pulmonary diffusing capacity, we computed the uptake of CO across a two-dimensional geometric capillary model containing a variable number of equally spaced RBCs. RBCs are circular or parachute shaped, with the same perimeter length. Total CO diffusing capacity (DLCO) and membrane diffusing capacity (DMCO) were calculated by a finite element method. DLCO calculated at two levels of alveolar PO2 were used to estimate DMCO by the Roughton-Forster (RF) technique. The same capillary model was subjected to morphometric analysis by the random linear intercept method to obtain morphometric estimates of DMCO. Results show that shape distortion of RBCs significantly reduces capillary diffusive gas uptake. Shape distortion exaggerates the conceptual errors inherent in the RF technique (J. Appl. Physiol. 79: 1039-1047, 1995); errors are exaggerated at a high capillary hematocrit. Shape distortion also introduces additional error in morphometric estimates of DMCO caused by a biased sampling distribution of random linear intercepts; errors are exaggerated at a low capillary hematocrit.

Algorithms↗
PubMed1995

[Geometrical modeling of the spine and the thorax for the biomechanical analysis of scoliotic deformities using the finite element method].

In order to study the biomechanical behavior of the whole human spine and thorax, as well as orthopaedic treatment effects, a new generation model is proposed, which includes a precise functional representation of the posterior part of the spine, while respecting computational capabilities. This paper presents the geometrical aspects of this model. The latter is built using an hybrid method which combines steroradiographic 3-D reconstructions of the spine and thorax [1] to serial CT scan 3-D reconstructions of typical human vertebrae and sternum [4] and published morphometric data of ribs [2, 3]. These anatomical structures were deformed in order to fit as well as possible the personalized data of scoliotic patients using geometrical transformations as well as interpolation or extrapolation techniques. In the posterior part, articular facets are modelled and parameterized as elementary surface shapes (plane, cylinder, sphere). For the articular facet geometry of a given normal subject, results revealed that the zygapophyseal facets are better represented by planes for T1 to T11 and by portions of cylinders for T12 to L5, which is in concordance with the literature [5, 6]. Evaluation of this modelling approach was done on 2 cadaveric vertebral segments. Parametric data obtained from the model were compared to precise measurements done on the vertebrae using a 3-D digitizer, and concordance was found. These personalized geometric informations were then used to build a finite element model [7], which will be useful to study scoliotic deformities as well as personalized orthopaedic treatments.

Humans↗
PubMed2005

Large-scale 3-D geometric reconstruction of the porcine coronary arterial vasculature based on detailed anatomical data.

The temporal and spatial distribution of coronary blood flow, pressure, and volume are determined by the branching pattern and three-dimensional (3-D) geometry of the coronary vasculature, and by the mechanics of heart wall and vascular tone. Consequently, a realistic simulation of coronary blood flow requires, as a first step, an accurate representation of the coronary vasculature in a 3-D model of the beating heart. In the present study, a large-scale stochastic reconstruction of the asymmetric coronary arterial trees (right coronary artery, RCA; left anterior descending, LAD; and left circumflex, LCx) of the porcine heart has been carried out to set the stage for future hemodynamic analysis. The model spans the entire coronary arterial tree down to the capillary vessels. The 3-D tree structure was reconstructed initially in rectangular slab geometry by means of global geometrical optimization using parallel simulated annealing (SA) algorithm. The SA optimization was subject to constraints prescribed by previously measured morphometric features of the coronary arterial trees. Subsequently, the reconstructed trees were mapped onto a prolate spheroid geometry of the heart. The transformed geometry was determined through least squares minimization of the related changes in both segments lengths and their angular characteristics. Vessel diameters were assigned based on a novel representation of diameter asymmetry along bifurcations. The reconstructed RCA, LAD and LCx arterial trees show qualitative resemblance to native coronary networks, and their morphological statistics are consistent with the measured data. The present model constitutes the first most extensive reconstruction of the entire coronary arterial system which will serve as a geometric foundation for future studies of flow in an anatomically accurate 3-D coronary vascular model.

Animals↗