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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↗
PubMed1989

[New findings on the embryogenesis of the uterus].

In this study including twelve embryos, aged 4 to 8 weeks, and twenty-one fetuses between 9 and 25 weeks, and a group of five still-born fetuses between 25 and 40 weeks, the authors used conventional techniques of histological preparations and immuno-chemistry according to the BSA technique (biotin-streptavidin with peroxidase labelling), in order to demonstrate that the uterus presents a "dual embryogenesis". The endometrium with its stroma and the transition zone endometrium-myometrium have a coelomic origin. The myometrium with the common connective tissue derive from primary mesenchyma. According to the authors, the "dual embryology" of the uterus, would permit simplifying the taxonomy of the histogenesis of uterine tumors.

Embryonic and Fetal Development↗
PubMed1989

[Histologic study of the gonads in ovarian differentiation during organogenesis].

We report the results of a histologic study of the differentiating ovary carried out in human embryos and fetuses. Up to the sixth week, the anlage of the gonad is formed by the proliferation of cells originating from the coelomic mesothelium; this proliferation starts with the migration of the primordial germ cells. Between the sixth and the tenth weeks, the primary mesenchyma invades the epithelial mass and divides it into "cords"; by division, the germ cells contained within the mass become ovocytes. At the tenth week, the gonad takes shape and is separated from the mesonephros. At the twelfth week, the gonad is formed of two zones; an outer zone formed of epithelial clusters arranged in rosettes around the ovocytes; and an inner, mesenchymal, zone that becomes the medulla and separates the outer epithelial zone from the remnants of the mesonephros. At the sixteenth week, the gonad becomes the ovary that contains millions of primordial follicles; each follicle consists of an ovocyte surrounded by a ring of granulosa cells originating from the coelomic epithelium; the follicles are separated from each other by mesenchymal cells that form the cortical stroma. The remnants of the mesonephros are clearly separated from the ovary by the medulla.(ABSTRACT TRUNCATED AT 250 WORDS)

Embryonic and Fetal Development↗
PubMed1989

[New findings on the embryogenesis of the vagina].

The authors have studied a series of twelve embryos between 4 and 8 weeks of age and 21 fetuses between 9 and 25 weeks of gestation. From this material they have made a study of the embryogenesis of the vagina, which shows that the whole of the vagina, and not only the lower third or fifth, is derived from the vaginal plate, this latter is the result of proliferation and fusion of the two sino-vaginal bulbs. This study supports the unitary theory ascribing formation of the vagina to ascension and extension of the vaginal plate which is derived from the cloacal sinus.

Embryonic and Fetal Development↗
PubMed1988

[Comparative morphological study of the peritoneal mesothelium and the germinal epithelium of the ovary. Histogenetic evidence for endometriosis].

The purpose of this study was to evaluate comparatively the morphology of germinal epithelium and of peritoneal mesothelial cells in women with and without endometriotic foci. In women without enometriotic foci, transmission electron microscopy revealed that plasma membranes of both cell types can form villous process, and that tonofilaments can be found in the cytoplasm; the microfibrils are well defined and may be arranged in perinuclear location or closely packed on the surface. Desmosomes are occasionally found in both cell types. In endometriotic foci, located either in the peritoneum or in the ovary, invaginations of the mesothelium into the underlying stroma are frequently observed, contiguous to well defined endometriotic tubules, or glandlike crypts. These structures are lined by a layer of cuboidal or high columnar cells. The cell membranes are well defined and run parallel to one another; small widening of the intercellular spaces is occasionally associated with a desmosome in the apical portion of the cell. These features may reflect Mullerian induction.

Adult↗
PubMed1988

Weibel-Palade bodies in pig megakaryocytes.

Originally described in vascular endothelial cells, Weibel-Palade bodies were considered as specific of this cellular type, as they have never been reported elsewhere. Weibel-Palade bodies serve as storage granules for von Willebrand factor which is stored in microtubular form. Besides endothelial cells von Willebrand factor is also synthetized by bone marrow megakaryocytes. Von Willebrand factor has been located in alpha-granules of megakaryocytes and blood platelets. We describe true Weibel-Palade bodies in pig megakaryocytes, and also alpha-granules which look like an evolutionary form of Weibel-Palade bodies. Von Willebrand Factor is most likely stored in microtubular form in these two types of structure. This is supported by the absence of microtubules in these granules in cells obtained from pigs homozygous for the von Willebrand disease (lacking totally this protein).

Animals↗
PubMed1987

[Ewing's sarcoma. Retrospective study of 108 cases with review of the literature].

108 cases of Ewing's Sarcoma are collected at the "Curie Institute" and studied by the authors using the modern Technics of electron microscopy, cytochemistry, immunohistochemistry and cytogenetics. They raise the histogenesis and etiological factors not entirely resolved yet at the light of literature review.

Diagnosis, Differential↗
PubMed1987

[Hodgkin's disease].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1987

[Lesions of coronary atherosclerosis in drug users. Preliminary studies].

A study of hearts removed during medicolegal autopsy of drug addicts after their sudden death demonstrated the constant presence of coronary lesions very similar to common atherosclerosis but remarkable by their magnitude, especially in patients dying at an age when atheromatous disease is relatively rare. Coronary circulation was studied in 10 cases by histoenzymatic, immunologic, histologic and ultrastructural examination of fresh and fixed tissues. The parietal thickening, noted in all cases to variable degrees, had provoked stenosis in several cases, preferentially in the proximal portion of the anterior interventricular vessel. On light and ultrastructural microscopy, the lesions observed were similar to atherosclerotic lesions, but differed in several respects and notably the absence of antiglobulin and the lack of increase of glycosaminoglycans. Although the relations between the drug and atheroma are undeniable, their mechanism is at present unknown.

Adolescent↗
PubMed1987

[Endometriosis of the uterine cervix. A hypothesis on its histogenesis].

Three cases of endometriosis of the cervix in association with the results of previous studies on the embryogenesis of the uterus made it possible during a morphological study for the authors to hypothesise that cervical endometriosis could develop in mullerian rests which persist in the stroma of the cervix. Menstrual blood incites the development, but degenerate menstrual fragments of endometrium do not implant to cause this development.

Adult↗
PubMed1987

[Tissue changes caused by the diathermy loop].

An attempt of classification of the effects induced by electro-resection on the squamous epithelium of the cervix is presented. It has been founded on predominant features observed on histologic material notably: acantholysis, cells segregation by lysis of intercellular bridges and dislodgment of basal cells from basement membrane by dissolution of reticulin fibers.

Adult↗
PubMed1986

[An integrated histogenetic concept of internal and external endometriosis].

The authors have studied the embryology of the uterus and have studied the comparative morphology of the internal foci of endometriosis, as well as the endometrium itself during the menstrual cycle. These studies have led them to think that the foci of endometriosis, whether they are internal or external, come from cells of coelomic mesothelium that persists in the transitional zone between the myometrium and the endometrium of the uterus, or in the mesothelium that covers the ovary, the tube and the pelvis under the stimulus of substances that are present in degenerate endometrial tissues during menstruation. This unitary idea of histogenesis makes it possible to consider under one heading, if not to unite, all endometriosis occurring anywhere according to their histogenic presentation under the same conditions of the tissues that surround them. It also makes it possible to explain the morphological similarity of endometriosis with the endometrium, although the biological behaviour of the two tissues is different. There is therefore a relationship between endometrium and endometriosis but not a filial one.

Endometriosis↗