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Biomedical subjects

L Orcel

Publications and source records attributed to L Orcel.

At least 55 records · Page 3Linked to original sources
PubMed1982

The evolution of experimental endarteritis in the rabbit abdominal aorta. Light and transmission electron microscopy.

Experimental aortic intimal thickening has been induced in rabbits by sheathing the vessel with a polyethylene cuff. The alterations have been examined by light and transmission electron microscopy, during 12 months. An irregular intimal thickening develops as soon as the 15th day and includes numerous myofibroblasts with some other cells of monocytic or endothelial type. Microfibrils, elastic aggregates and collagen fibers are found in the intercellular space. Simultaneously, the media undergoes a fragmentation of the elastic laminae and the adventitia shows a capillary angiectasis and a granuloma. After 3 months there is, between the intimal smooth muscle cells, a progressive increase of elastic and collagenous material. In the media, elastic break up becomes more frequent after the 4th month and myocytes appear increasingly atrophic, which facilitates the extension of fibrosis. This is accompanied at times by a thinning of the arterial wall with or without localized disappearance of the media. All these modifications are discussed and compared to what we had previously found in the femoral artery [12].

Aging↗
PubMed1982

["Vestigial cells" of the transitional area of the uterine-cervix. Comparative morphological study with the subcylindrical-reserve-cells (author's transl)].

The squamo-cylindrical junction represents a transitional area of unstable epithelium. It consists of slightly differentiated cells which disclosed resemblance in morphological pattern with germinal cells of the basal layer in the exocervical squamous epithelium. These unstable cells, according to the authors, may be derived from the cranial, most cephalic extend of the sinusal vaginal plate which had formed the epithelium of the entire vagina and the vaginal portion of the cervix up to the squamo-columnar junction. Ultrastructural analysis disclosed no similarities between cells of the squamo-columnar junction and subcylindrical reserve cells which exhibited sometimes resemblance to the "mesenchymal cells" found within the surrounding stroma.

Cervix Uteri↗
PubMed1981

The basement membrane in the carcinoma in situ of the cervix: a morphological study.

A morphological study of the basement membrane in the carcinoma in situ of the cervix has been carried out. Undifferentiated carcinoma in situ that arises usually from the squamocolumnar junction and which extends into the endocervical canal, always shows a continuous and clearly delineated basement membrane, which runs parallel to the basal layer. It has a homogeneous appearance. The hemidesmosomes attached to the lamina propria are quite normal and there are no slender protrusions from basal cells into the lamina propria. Differentiated carcinoma in situ, that originates in the squamous epithelium of the portio, may extend either in the direction of vagina, or towards the endocervical canal. It is always underlined by a basement membrane loosely constituted of irregular of fragmented reticular fibers; it frequently looses its homogeneous appearance and may be dehiscent or duplicated. Basal cells send down small pseudopods or threadlike extensions into the lamina propria. The authors suggest that in the management of carcinoma in situ of the cervix, one should take into consideration the direction of spread and the stroma-invasion potential of the carcinoma. These histologic patterns carry with them a very important morphologic implication, namely 'cells differentiation' of the carcinoma.

Basement Membrane↗
PubMed1981

A hypothesis on the origin of the subcylindrical reserve cells of the endocervix.

The structural features of subcylindrical reserve cells of the endocervix are presented. Reserve cells varied in shape. They were randomly oriented and most had a bean-like or spindle shape. Some were loosely apposed with no desmosomes while others were separated by an intercellular matrix. Their nuclei were oval or fusiform, with a prominent nucleolus. Coarse chromatin plaques are distributed irregularly within the nuclei, and surface membrane showed cytoplasmic projections. Within the connective tissue, close to the basal membrane, could be found cells that showed the same structural features; some of them were partially enveloped by amorphous ground substance and collagen, and had small processes extending from the cell surface in the direction of the epithelial layer. Ultrastructural analysis of these cells disclosed some similarities with fibroblasts in the surrounding stroma, and suggested that they were primitive mesenchymal cells originating from Müllerian mesenchyme.

Cell Nucleolus↗
PubMed1981

Electron microscopic study of intercellular canalicular systems in the parietal fetal membranes.

An electron microscopic study of the amnion and the chorionic cytotrophoblast has demonstrated the existence of intercellular channels running between the lateral sides of the cells with typical junctional complexes sealing their proximal ends. In the amnion these channels open through the basal lamina into the connective tissue, and in the chorionic cytotrophoblast they open in the direction of the decidua. This situation seems to indicate that fluid emerges from the open mouth of the amniotic intercellular channels and then continues to flow into the channels of the cytotrophoblast, across its podocytic processes, to be discharged into the decidua, and finally drained by maternal decidual vessels. This morphological study suggests that parietal fetal membranes might be an important route for transport of solute and fluid from the amniotic fluid to the maternal circulation.

Amnion↗
PubMed1980

Fetal membrane morphology and circulation of the liquor amnii.

Morphological study of the human fetal membranes (at the term of pregnancy) shows that under the amniochorion lies the chorionic cytophoblast, which completely surrounds the amniotic cavity. Chorionic cytotrophoblast as well as parietal decidua persist until full term and remain well-developed. Within trophoblastic cells there are numerous canalicular formations bordered by microvilli resembling those observed between amniotic cells. The authors therefore believe that the circulation of amniotic fluid, after traversing the amnion, will continue through the intercellular canaliculi of the chorionic cytotrophoblast to reach the decidua parietalis. All the components of this complex membrane must play a part in the amniotic fluid circulation.

Amnion↗
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↗