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Biomedical subjects

J Mignot

Publications and source records attributed to J Mignot.

At least 19 recordsLinked to original sources
PubMed1989

Quick method of measuring the furrows distribution on skin surface replicas.

A fast method of measuring the distribution of furrows can be obtained via the analysis of TV camera images of skin replicas. These replicas are either negative (or direct) or positive. Reflected or transmitted light is used, depending on the type of replica. Each point of the matrix (256 x 256 pixels) is digitised over 6 bits (64 levels) and treated by a personal computer (IBM AT or PC). With such an image, it is not possible to obtain significant results without eliminating noise and enhancing the furrows. Specific software is written in processor language 8086 to obtain a real time system. The distribution of skin furrows is quantified for several interesting cases such as the ageing of the skin or the effect of stress.

Aging↗
PubMed1987

The algorithm of the cockshafer walk: a movement automaton applied to the construction of the integrated optical density profile of prometaphase chromosomes.

We present an algorithm designed to obtain the optical density profile of prometaphase chromosomes. Our movement automation (the cockshafer) is able to move along the median axis of the chromosome. The criterion used to maintain the correct movement direction lies on the distances from the automaton position to the side boundaries (lengths of the cockshafer antennae). The automaton movements are regulated by rules defined in a decision repertory. This new method does not use a transformation of the image and does not require any prior knowledge of the shape of the chromosome to be sampled.

Algorithms↗
PubMed1984

A perimeter algorithm applied to lung pathology.

A new image analyser, the NS 2000, explores the image using 256 photodiodes and, according to an adjustable threshold, converts it into a set of digital points of logical level 0 or 1. The method of fitting squares of increasing size consists of checking the presence of a square of a given size and of a given logical value throughout the image studied and gives the areas of successive erosions of the image. Using the parameters provided by the device one can obtain the total boundary BA per unit area for the phase studied, which is proportional to the number of squares having points of the two logical levels. Errors in length measurement as a function of orientation and for isotropic structures are compared to other automatic perimeter algorithms and to manual square grid measurement. Using the parameters provided by the device for the quantitative evaluation of lesions of elastase induced emphysema in hamster lungs, the values obtained for internal surface area (ISA) of alveoli, are lower by about 40% in elastase treated hamsters when compared to normal controls. This difference is highly significant (P less than 0.001) and the results obtained by the described method are in good agreement with those obtained by the classical manual procedure. Efficiency, defined as the precision of the estimate per unit measurement time on a given set of sample units (pictures in this paper), is given for both NS 2000 and manual procedures. The results obtained show comparable values but the automatic procedure includes a statistical treatment and it is significantly faster on histological sections than on micrographs, which was not the case with the manual method.

Animals↗
PubMed1983

Capillary perfusion patterns in reperfused ischemic subendocardial myocardium: experimental study using fluorescent dextran.

The relationship between functional capillary perfusion patterns and sarcolemmal membrane permeability in localized acute myocardial ischemia was investigated in the rat model. The macromolecule dextran (MW 150,000) labeled with fluorescein (FITC) was intravenously injected. In histological sections, the label fluorescence showed those capillaries which had been perfused by the stained plasma; the blood-tissue barrier could be explored by detection of fluorescein in interstitial spaces and/or within the myocardial cells. Morphological parameters were calculated by semiautomatic image analysis. The data obtained indicate that (1) there is a great heterogeneity in the pattern of capillary perfusion within the reperfused ischemic myocardium; (2) as early as 20 min after coronary artery clamping followed by short reperfusion, the macromolecular tracer can be seen in the cytoplasm of muscle cells randomly distributed in subendocardial areas; (3) only the underperfused areas display permeated myocardial cells. It is suggested that capillary perfusion varies from site to site depending on the difference in cellular membrane permeability changes. The ischemia-induced cell changes can lead to capillary filling defects and an increase in coronary flow resistance. Whether the inadequate blood flow upon reperfusion contributes to further myocyte damage remains a matter of debate.

Acute Disease↗
PubMed1982

[Histological morphometric methods. II. Automatic analysers (author's transl)].

Histological morphometric methods can be divided into three groups depending on their automation degree: manual methods, semi-automatic methods, fully automatic methods. Among fully automated image analysers, one can separate devices into three main subgroups: 1 - general purpose systems controlled by software can be programmed to undertake an infinite variety of tasks. 2 - general purpose systems with limited repertoire of analysis, controlled by hardware programs. 3 - simple task instruments controlled by hardware programs (e.g. Hematrak, Leitz). Whichever instrument is used, three steps take place in an automated image analysis procedure: 1 - image numeration. 2 - parameters extraction. 3 - parameters interpretation. The NS 2000 image analyser belonged to the 2nd subgroup of the above mentioned systems. Its built-in hardware algorithm works just like successive erosions on images. An example (breast carcinoma tissue section) is given in order to illustrate performances of this peculiar image analyser.

Automation↗
PubMed1981

[Quantitative assessment of labial salivary gland sclerosis in patients with diffuse scleroderma (author's transl)].

Biopsies of the lips were performed on 27 patients (7 male and 20 female; mean age, 58 years) with diffuse scleroderma and on 10 healthy subjects serving as controls. The degree of intralobular sclerosis in labial salivary glands was measured on tissue sections by an automated morphometric analysis technique. Collagenous compared with controls. It was independent from the type of cell infiltrating the gland and from the evolution potential of the disease, but it correlated with its duration and seemed to be specific to scleroderma.

Adult↗
PubMed1981

[Histomorphometric study of lymphocyte population in thyroid in Graves' disease after treatment (author's transl)].

The degree of lymphocyte infiltration in subtotal thyroidectomy specimens from patients with treated Graves' disease varies greatly from one case to another. A morphometric study, employing standard and immunofluorescent slides was conducted to evaluate possible statistical correlations between clinical and morphological findings. Quantitative lymphoplasmocytic cellularity differences appeared to be related to the course of the disease. Lymphocyte infiltration was greater in patients with long-standing disease and/or relapses.

Fluorescent Antibody Technique↗
PubMed1981

[Histological morphometric methods. I. Semi-automatic methods on graphic tables (author's transl)].

Two kinds of parameters are accessible by histological morphometric methods: --actual quantitative ones (e.g. length, area) --discontinuous ones (e.g. cells, nucleus or mitochondrium counting). Measures were all achieved by manual methods in past. Nowadays, apparatus are existing that can solve semi-automatically histomorphometric problems. These apparatus are variously named digitizer, digitizing table, digitalizing table, graphic table and so on. Two histomorphometric examples are described one concerning breast carcinoma the other myocardial vascularization in rats. They both have been treated on a graphic table. Problems and their solutions are developed.

Animals↗
PubMed1979

[Measurement of the position and intensity of chromosomal denaturation bands by an automatic system].

The band density profile of a marked chromosome was obtained using a photodiode collector combined with a minicalculator, working with an ordinary photographic document. The measurement was carried out over 10 to 20 300-point lines oriented longitudinally along the chromosome. The profile obtained corresponds to the sum of the values of each of these lines. The proposed systems's originality resides in its ability to determine the position and intensity of a band over the entire thickness of the chromosome.

Autoanalysis↗