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L Orcel

Publications and source records attributed to L Orcel.

At least 19 recordsLinked to original sources
PubMed1991

Heterogeneous distribution of Weibel-Palade bodies and von Willebrand factor along the porcine vascular tree.

Vessels obtained from different levels of pig vascular tree were examined by transmission electron microscope, with the aim of determining whether or not their endothelial cells contain Weibel-Palade bodies (WPB). As these organelles are known to store the von Willebrand factor (vWF), a two-step immunogold labeling of this protein also was performed. Our results showed for the first time a heterogeneous distribution of WPB along the vascular tree of the normal pig: These structures were absent from the thoracic aorta, rare in the abdominal aorta, present in myocardial capillaries, and numerous in the inferior vena cava and pulmonary artery. Atypical WPB devoid of tubules were seen in all endothelial cells. The ultrastructural labeling of vWF demonstrated its presence only in the WPB, being absent in the subendothelium, and showed the same variation in its distribution along the vascular tree as for its storage organelle. Pigs homozygous for the von Willebrand disease were found to have only the atypical WPB, and do not express the vWF.

Aging↗
PubMed1978

[Analytical morphodynamics. Practical applications].

The analytical morphodynamic method, based on the study of the fate of the biogic units of an organ at the level of well or poorly developed lesions, has been applied to the analysis of chronic obliterating arteriopathies of the extremities, of benign tumors of the mammary parenchyma, and of malignant hepatomas. In morbid states as different as a reactive process and a benign or malignant neoplastic process, it allowed to reconstritute the histogenesis of complex tissue changes and led to interesting prospects, in the field of general biology and pathogenesis.

Arteriosclerosis Obliterans↗
PubMed1978

[Histochemical and histoenzymatic study of experimental endarteritis in rabbits. I. Femoral endarteritis].

The parietal reaction after placing a cuff of polyethylene around the femoral artery has been studied in 18 (2,5 - 3 months old) male rabbits by using histologic, histochemical (4 macromolecular substances) and histoenzymatic techniques (16 enzymatic activities). Studies were performed on the 1st, 3rd, 5th, 15th and 21st day, and every 15 days during the 3 months of the experiment. This process induced rapidly in each animal a parietal reaction with adventitial oedema (1st day), hypoxia of the media (1st -5th day), cytoenzymatic activation followed by a cellular transformation and proliferation of the intima-media, that forms a diffuse intimal thickening (adaptation). Most cells of the thickening were, by their enzymatic activities, quite comparable to immature smooth muscle cells, which probably emigrated from the media: intense LDH, NADH2 - TR; moderate G6P-DH, SDH, NADPH2 - TR, alpha-GP-DH, ATP/ase; weak ICHD, beta-HB-DH. Moreover, some reactions (accentuation of beta-Glu/ase, UDGP-DH, Glu-DH, 5'N/ase) besides suggested the active participation of the cells in the production of extracellular conjonctive constituents, because the histochemical studies revealed the presence of metachromatic glycosamino-glycanes and positive APS substances during the edification of the diffuse intimal thickening. In advanced thickening, an histoenzymatic duality was observed, that might prove the double origin of the thickening cells: some superficial cells had the enzymatic characteristics of endothelial cells (increased activity of aerobic oxydoreductases). At every stage of the study, the thickening cells differed from the atherocytes by a lack of lipids in their cytoplasm.

Animals↗
PubMed1978

[Histochemical and histoenzymatic study of experimental endarteritis in rabbits. II. Aortic endarteritis].

The placement of a polyethylene cuff around the abdominal aorta of 20 male rabbits 2,5 to 3 months old induce an adventitial reaction characterized by edema (7th day), fibroblastic proliferation (7th - 15th day), fibrosis and sclerosis (2nd - 3rd month), changes in the media including cytoenzymatic activation (1st - 3rd week), signs of hypoxia, degenerative and productive processes leading to intimal tickening. Histoenzymatic characteristics of the intimal thickening cells look like activities of smooth muscle cells, while the activities of some cellular areas recalled those of endothelial cells (high aerobic oxydoreductases and ATP/ase activities). This histoenzymatic duality is perhaps related to the histogenetic filiation of the intimal thickening cells. Histochemical data (metachromasia, alcianophilia, APS +) suggest that these cells are able to synthesize different elements of the extracellular matrix. All these features resemble femoral endarteritis obtained by the same process; moreover, in aorta the endarteritis evolves more slowly, the cellular proliferation is later and focused, the signs of hypoxia and necrosis and more pronounced. These differences are probably related to structural and metabolic dissimilarities of the two vessels, and to differences in their cellular reactivity.

Animals↗
PubMed1978

[The histogenetic significance of dysplastic lesions of the cervix (author's transl)].

From the morphological studies that they have carried out the authors describe dysplasias of the cervix of the uterus as a collection of lesions developed from the vestigial cells which are situated at the endo-exocervical junction. The embryological origin of this junction is the sinus. These dysplasias consist of cells with basophil cytoplasm with edges that are not sharp. These form streams which run from the external os of the cervix towards the endocervix, where they replace and disturb the cylindrical epithelium wherever they meet it. These lesions may take on two forms: regular or irregular according to the degree of nucleo-cytoplasmic disharmony. The slow and insidious evolution of these lesions must be distinguished from dystrophic endocervical lesions which are caused by a disturbance in the nutrition of the tissues, which itself is of hormonal or inflammatory origin, and from exocervical lesions which, in common with all lesions of the malpighian mucosa, can undergo atypical scarring.

Cell Nucleus↗
PubMed1978

[The dynamics of the amniotic fluid].

Morphological study of the ovular membranes showing that under the amnion, until term, there persists perfectly live and active chorial cytotrophoblast covered by a well vascularised and developed parietal decidua. Under the electron microscopy, the apical pole of the amniotic cells as well as their intercellular space are bordered by microvilli. Their basal pole has squat pedicels. The chorion which supports the amnion is avascular. The surface of the cytotrophoblast opposite the chorio-amnion is raised by numerous protuberances in the form of pedicels. The trophoblast is also furrowed by intercellular canals bordered by microvilli and reinforced by desmosomes. Two cellular appearances may be distinguished in the trophoblast: elements similar to the syncytial type with the characteristics of steroid cells and elements of a Langhans type which may play a role in protein synthesis. The decidual cells, in a quinconcial perivascular arrangement, are rich in pinocytotic vesicles. Thus whilst it is undeniable that the foetus plays a certain role in the dynamics of the amniotic fluid by swallowing and urinary excretion, these phenomena are minimal in relation to exchanges through the ovular membranes. Transamniotic passage is the first stage in movement of the fluid. The chorion, by virtue of its plexiform, areolar structure forms the next stop. From the chorion, the circulation continues through the intercellular canals of the trophoblast and the amniotic fluid is thus brought into the well vascularised parietal decidua. In addition to this extracellular circulation, the authors fell that there exists an intracellular passage by uptake and secretion, as evidenced by the high degree of pinocytosis within the cells.

Amnion↗
PubMedDate not supplied

[Vascular lesions of the endometrium in spontaneous abortion].

On the basis of a histological study of vascular lesions of the endometrium following 108 cases of spontaneous abortion, the authors propose the following conclusions: 1) In the first six weeks of pregnancy, early abortion results more often from a primary ovular defect than from any abnormality in the maternal environment, of endogenous or exogenous origin and capable of resulting in a lesion of the endometrium or its vascularisation. The structure of the walls of the spiral arteries of pregnancy is almost invariably normal. 2) By contrast, in late abortions, arterial lesions--and in particular fibrosis--may play a role. This occurs however when the basal arteries with a well-differentiated elastic structure are involved. The spiral arteries of pregnancy and the utero-placentar arteries are involved only by lesions of vasculitis secondary to inflammatory phenomena as a result of retention of the products of conception or by pseudo-atheromatous lesions resulting from the deposition of degenerated cyto-trophoblastic elements, but never from true arteriosclerotic lesions.

Abortion, Spontaneous↗
PubMedDate not supplied

[Anatomic pathological aspects of chronic obliterating arteriopathies of the extremities (author's transl)].

It appears that the classical concept of atherosclerosis cannot be applied indiscriminately to all cases and that it is essentially valid for the aorta and its large branches of predominantly elastic structure. When more peripheral arterial trunks are considered, those of muscular type, the lesions are in great part characterized by a dystrophic fibrosis of the media, associated with a diffuse intimal thickening and with stratified fibro-hyaline plaques narrowing the lumen; the latter are responsible for the circulatory insufficiency and gangrene. Comparative analysis of 50 surgical specimens allow us to conclude that those fibro-hyaline plaques represent progressively stratified parietal thrombi that are populated by myocytes, at the contact of which ultrastructural investigation reveals important phenomena of elastogenesis and elastolysis. Most probably, the myocytes originate from the media, through fenestration within the inner elastic membrane. These facts have more than just a purely speculative interest: they express the great plasticity of the arterial walls and their capacity of adaptation to new hemodynamic and biologic conditions. It is interesting to note that this lesion constantly presents signs of metabolic activity and structural remodeling despite its long standing caracter.

Aging↗
PubMedDate not supplied

[Use of a titrated extract of Centella asiatica in chronic hepatic disorders (author's transl)].

The authors report their preliminary results of a study of the possible therapeutic activity of a titrated extract of Centella asiatica in chronic hepatic disorders. Early results are encouraging, especially from a histological point of view, where improvement in the criteria evaluated was noted in 5 of the 12 patients treated for the longest time. These results have to be assessed in a critical manner until confirmation is obtained by complementary studies.

Adult↗