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J A Gaillard

Publications and source records attributed to J A Gaillard.

At least 19 recordsLinked to original sources
PubMed1992

Developmental regulation of villin gene expression in the epithelial cell lineages of mouse digestive and urogenital tracts.

The expression of villin, an actin-binding protein and major structural component of the brush border of specialized absorptive cells, was studied during mouse embryogenesis. We show that the ontogeny of villin expression is limited to the epithelial cell lineages of the digestive and uro-genital tracts and accounts for the tissue-specific expression observed in adult mice. This spatiotemporal pattern of villin expression is distinctive in sequence, intensity, regional distribution and polarization. During the development of the primitive gut, villin is faintly and discontinuously expressed in the invaginating foregut but it is expressed in every cell bordering the hindgut pocket. Later, villin expression increases along the developing intestine and concentrates in the brush border of the epithelium bordering the villi. In gut derivatives, villin is present in liver and pancreas primordia but only biliary and pancreatic cells maintain a faint villin expression as observed in adults. In the urogenital tract, mesonephric tubules are the first mesodermal derived structures to express villin. This expression is maintained in the ductuli efferents, paradidymis and epoöphoron. Villin then appears in the proximal metanephric tubules and later increases and concentrates in the brush border of the renal proximal tubular epithelial cells. Thus villin expression can be considered as an early marker of the endodermal cell lineage during the development of the digestive system. Conversely, during the development of the excretory and genital system, villin is only expressed after the mesenchyme/epithelium conversion following the appearance of tubular structures. These observations emphasize the multiple levels of regulation of villin gene activity that occur during mouse embryogenesis and account for the strict pattern of tissue-specific expression observed in adults. In the future, regulatory elements of the villin gene may be used to target the early expression of oncogenes to the digestive and urogenital tracts of transgenic mice.

Animals↗
PubMed1988

Villin expression in the visceral endoderm and in the gut anlage during early mouse embryogenesis.

Villin is an evolutionarily well conserved, Ca2+ regulated actin-binding protein, and a major structural component of the brush border of specialized absorptive cells. Using paraffin sections and an affinity purified polyclonal anti-villin antibody, we have investigated the early expression of villin during mouse embryogenesis. Villin is first detectable at the early post-implantation stage in visceral endodermal cells at the periphery of the egg cylinder. In this extra embryonic layer, the expression of villin increases and then persists until full term gestation. In the embryo, villin first appears in gut anlage during the axial rotation. Using the same methodology, villin expression is also demonstrated in differentiating embryoid bodies from a teratocarcinoma. Both in extra embryonic and embryonic extracts, villin expression is confirmed by immunoblot and Northern blot analysis which reveal, respectively, a single polypeptide of 93 kd and an mRNA of 3.4 kb in length, two well defined parameters for adult mouse villin gene expression. The results presented here show that paraffin sections allow very sensitive and highly resolutive detection of antigens in early embryogenesis. They provide a detailed developmental profile of villin expression and demonstrate the usefulness of villin as a marker for epithelial cells involved in absorptive processes.

Animals↗
PubMed1984

[Demonstration of plasmacytes in gingival immune defense units in dermoid cysts of the ovary].

Gingival units of immunological defense have been observed surrounding erupted teeth in the connective tissue of the wall of ovarian dermoid cysts. Using a modified immunoperoxidase technique, the production of IgA, IgG and J chains has been clearly detected. This technique works perfectly on decalcified specimens. Since dermoid cysts are not contaminated, the origin of the plasma-cells in these units is presumed to be triggered by other antigenic factors. These are present in epithelium and provided a possible explanation for the "homing" of lymph-cells migrating from the immune system.

Dermoid Cyst↗
PubMed1981

[Presence of lymph-vascular anatomical units in dermoid cysts and the probable existence of a local immune defense system in various tissues].

Studies on tooth eruption in several ovarian dermoïd cysts showing the existence of immune defense gingival structures has allowed the presence of similar structures associated with respiratory and digestive differentiation zones to be observed. These structures are formed of histiocyto-plasmocyto-lymphocytes associated with capillary loops. The origin and histogenesis of those structures remains to be clarified but they suggest the probable existence of localised immune defense systems within certain tissues.

Cell Differentiation↗
PubMed1979

[Interpretation of the gingival inflammatory infiltrate].

The investigation of tooth eruption in dermoid cysts of the ovary allows one to observe in the chorion at the level of the epithelial attachment, an anatomical component that seems to correspond to a local system of defense. Up until now this has been considered to be a secondary inflammatory response resulting from the bacterial or mechanical assault. This component is found to form when the tooth erupts and constitutes an important element in the physico-pathogical process and of the immune response of the dental organ.

Animals↗
PubMed1978

[The formation of tooth germs in teratomas].

The teeth buds which are observed in some teratomas ought to provide a useful system for the study of the development of organ structures in these tumours. They exhibit well defined characteristics in space and time. In contrast with normal development tooth bud formation in teratomas display malformations and other observable characteristics which are primarily the consequence of defects in coordination of activities among cells. Cyto-differentiation appears to be normal and the defective organogenesis must represent a breakdown of the principles which underlie the organization of structures. The possible role of the environment in organizing structure is discussed. Teratomas are unique biological systems which display in a dynamic way a panoply of teratological developmental processes of which teeth buds represent a fragmentary, repetitive and conspicuous expression.

Cell Differentiation↗
PubMed1977

[Odontogenesis, organogenetic model in teratomas: crown formation].

Using the technique of 3 dimensional reconstruction, the various steps involved in the formation and growth of the crown of a tooth primordium observed in a complex ovarian teratoma have been compared with that occurring in dermoid cysts and in the normal dental system. Inside dermoid cysts, the characteristic form of the tooth is established during the production of the dentine and enamel and the process is often similar to that occurring during normal tooth development. In teratomas, however, organogenesis and morphogenesis take place within a system undergoing multidirectional development. They are dissociated during both the embryonic stage and that of a structural formation. Morphogenesis is the most disturbed and the role of the environment is presumably therefore very important.

Dermoid Cyst↗
PubMed1975

[Odontogenesis, organogenic model using teratomas].

The study of odontogenesis in teratomas, leads to the following observations. Conspicuous odontogenic fields are present in the vicinity of pluri-differentiated cystic structures. Tooth germs are connected to the walls of the cysts by an anastomosed dental laminar. The teeth developing in teratoma are not comparable to the normal process which is harmonized when the formation and the distribution of the various parts are concerned. They are deformed in appearance but not in the same way as the classic genetic malformations. The origin of both epithelial and mesenchymal parts is still not completely understood.

Adult↗
PubMed1974

Antiinflammatory effects of murine malignant cells.

Development of teratocarcinoma does not impair immunization of mice against Listeria monocytogenes. Endotoxin injection a short time before tumor cell inoculation allows the growth of teratocarcinoma in non syngenic mice despite immune stimulation. In contrast with this absence of impaired systematic immunity, teratocarcinoma cells were found to repulse macrophages in vitro. This effect on macrophages was also found with three other malignant cells and with trophoblast cells. In vivo, teratocarcinoma cells were found to impair local inflammation. These cells and other malignant cells are able to produce a compound(s) of molecular weight between 10(3) and 10(4), which prevents inflammatory reaction. These results suggest that mouse teratocarcinomas and other tumors by-pass the host immunological system of surveillance by at least two mechanisms: a direct toxic effect on macrophages and the release of an inhibitor of inflammation. The possible relations between these properties of malignant cells and physiological functions of trophoblast are discussed.

Animals↗
PubMedDate not supplied

[Experimental terato-carcinoma: behavior of embryoid bodies inoculated into the abdominal cavity of syngeneic mice].

A suspension of CE "44" embryoïd-bodies obtained from a transplanted OTT 60-50 subline was injected into the abdominal cavity of syngeneic L 129 mice. Terato-carcinoma and ascitic fluid were produced the latter containing embryoïds. In situ examinations were made by serial transverse sectioning of the entire abdomen. The reconstruction of the sequence of events occuring after inoculation was achieved by killing the animals at different time after inoculation. This analysis showed that embryoïd-bodies appear quite similar to blastulas and that they are attracted to evolving granulomas in the peritoneum. Blastulas attach through their outer wall which then breaks to permit the inner-cell masses to penetrate through the hole and contribute towards the subsequent development of terato-carcinomas.

Animals↗
PubMedDate not supplied

[Significance of the endodermal sinus tumor (Teilum) and of simplified teratoma of vitelline determination].

The histogenesis of yolk-sac tumors has been explained by a selective cloning for extra-embryonic entoblast amongst totipotent carcinoma stemcells. The diverses appearances of the tumor growths are expressed mainly in the range of cyto-differentiations of entoblastic tissue rather than in their ability to form structures which mimick the yolk-sac. The process is clearly apparent in embryoids which are becoming disorganized and during the course of experimentally induced mouse parietal endodermal carcinoma. The latter's appearance is strong evidence that the laws of specificity are obeyed. Human tumors should be analyzed through human embryology. Some paradoxical aspects emerge occasionally due to the angiogenesic capabilities of the neoplastic vitelline tissue, and to the correlations of this tissue with the stromal vascular response.

Animals↗