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L Evrard

Publications and source records attributed to L Evrard.

At least 19 recordsLinked to original sources
PubMed2005

[Expression of caspase 3 and p53 during physiological apoptosis and apoptosis induced by three teratologic agents during early craniofacial development of the mouse embryo].

The neural crest-derived mesectoderm gives rise to physiologic apoptosis areas in early vertebrate embryos. Certain teratologic agents increase this phenomenon. The purpose of this work was to detect caspase 3 (which is associated with the apoptosis cascade) and p53 in cell death areas, both during physiological apoptosis and during apoptosis induced by three agents (retinoic acid, methyl-triazene, irradiation). Antibody revelation was performed using the aBC peroxidase kit. Quantifications were also performed on histological sections. We observed caspase 3 uptake on some apoptotic and preapoptotic cells in control embryos, and in the embryos exposed to the three teratogens. Immunoreactivity generally preceded the development of cytological features of apoptosis. However, p53 was expressed only in the embryos exposed to ionizing radiation and methyl-triazene (an alkylating agent), but not significantly in embryos exposed to retinoic acid. The present results throw some light on apoptosis mechanisms in several teratologic conditions.

Animals↗
PubMed2004

[Histologic and ultrastructural features of cell death both physiological and induced by two different teratogens in branchial arches of mouse embryo].

AIM OF THE STUDY: To observe and compare cell death process both physiological and associated with the administration of two different teratogens (irradiation and retinoic acid) inside cephalic mesectoderm. MATERIAL AND METHODS: Irradiated mice: 2 Gy were administered to E 9 embryos. Retinoic acid: 60 mg/kg were gave to E 8 or E 9 embryos. E 9 - 9.5 and E 10 embryos were removed. E 9 - E 9.5 and E 10 control specimens were collected. We used semi-thin sections and ultra-thin sections observed with transmission electron microscope. RESULTS: The major process is apoptosis, which is increased in experimental embryos compared to control specimens. However, autophagy was observed in retinoic acid-treated embryos, while necrosis can rarely occurs after irradiation. CONCLUSION: If the common process seems to be apoptosis, both teratological models differs owing to their respective secondary features. These differences should be explained by the specific pathogenesis of both teratological agents: ligand-receptor reaction and Hox system disruption in retinoic acid administration, direct aggression against DNA and diffuse cell death process following irradiation. Furthermore, congenital malformations induced by these teratogens are quite different. This can be partially explained by a specific blow of different cellular subpopulations.

Animals↗
PubMed2004

[Oral verrucous carcinoma].

Verrucous carcinoma is a rare, low-grade, well-differentiated form of squamous cell carcinoma seen on skin and mucosa. It is a slow-growing and locally aggressive tumor whose standard treatment is surgery. A case of strongly invasive oral verrucous carcinoma is presented with the medical history. The differential diagnosis of this neoplasm is difficult and requires clinic and pathologic data confrontation. In this paper, the importance of knowing the malignant potential of this lesion is stressed. Indeed, in 20% of verrucous carcinoma, foci of squamous cell carcinoma can be found. A review of literature and a differential diagnosis of verrucous carcinoma are presented.

Biopsy↗
PubMed2002

[Heat shock proteins, embryogenesis and evolution].

We present results about immunohistochemical identification of several heat shock proteins (HSP'S) during mouse normal and teratological embryogenesis. Apoptotic cells express very specifically and precociously HSP 110. This fact permits to identify apoptotic cells before apparition of morphologic features of apoptosis, but also to quantify the process of cell death in some teratological models, particularly administration of retinoic acid. HSP 86 is expressed in some cell populations, and particularly permanent in germ cells. Our observations brought us to discuss the potential protective role of HSP on germ cells, and the consequence of their inactivation in the macroevolution process, as well as the role of apoptosis in teratology.

Animals↗
PubMed2002

[The stomatology and maxillo-facial surgery department].

Initially devoted to emergencies, the Department of Oral and Maxillofacial Surgery has grown considerably since 1979. The department now consists of a Maxillofacial Surgery Unit supplemented by several specialised Units in charge of oncology, orthodontics and orthognathic surgery, implantology and all dental specialities. The main themes of research developed in the department include the healing process of oral tissues, the teratogenic effects of various compounds on the cranio-facial region, the study of apoptosis, the role of heat shock proteins, and the management of craniofacial dysmorphosis. These studies have a direct impact on patient management.

Belgium↗
PubMed2000

Chaperones in the parotid gland: localization of heat shock proteins in human adult salivary glands.

Heat shock proteins (HSPs) are expressed or increased in response to various biological stresses. Moreover, these 'stress proteins' seem to be expressed by some cells living in physiological conditions. From then on, they could play an important physiological role in normal cell functioning. The best-known physiological role of these HSP proteins is to act as 'molecular chaperones'. In this context, we have investigated the immunohistochemical expression of HSP27, HSP70, HSP90 and HSP110 in 10 human adult salivary glands. To highlight the presence of RNAm encoding HSP70, an in situ hybridization was performed. In our material, HSP27 was strongly expressed in the cytoplasm of striated duct cells and in some myoepithelial cells. The same localization was less stained for HSP70 and HSP90. The immunocytochemical reaction was weak or negative for HSP110 in striated ducts. HSPs were not expressed in acinic cells. In situ hybridization gave a positive signal in striated ducts with a probe encoding HSP70. Epithelial cells of the striated ducts and myoepithelial cells expressed HSP27, HSP70 and HSP90. These HSPs probably act in part as molecular chaperones for protein synthesis, transport and for several interactions between HSPs and different proteins.

Adult↗
PubMed2000

[Expression of heat shock proteins in salivary gland tumors. Immunohistochemical study of HSP27, HSP70, HSP90, and HSP110: apropos of 50 cases].

Heat shock proteins (HSPs) are known to be increased in response to biological stress. Recently some authors described their presence in tumors. Our immunohistochemical investigations revealed the expression of HSP27, HSP70, HSP90 and HSP110 in most of benign tumors of salivary glands (33 cases). In the malignant tumors, the reaction was immunopositive for HSP70 and HSP90 in 13/17 cases; but HSP27 and HSP110 were only expressed in 5/17 cases. In conclusion HSPs were expressed less in malignant than in benign cells. These results suggest that the loss of some HSPs may be a possible sign of malignancy.

HSP110 Heat-Shock Proteins↗
PubMed1999

Cranio-facial dysmorphism: experimental study in the mouse, clinical applications.

To obtain a better understanding of mandibulo-facial dysostosis and hemicraniofacial microsomia in man, the authors carried out a histologic and scanning electron microscope study of the facial malformations produced in mouse embryos by retinoic acid and methyl-triazene. The administration of 400 mg/kg 13 cis-retinoic acid (RA) to pregnant C57BL mice on day 9 of gestation produced anomalies of the cephalic extremity in the embryos resembling human mandibulo-facial dysostosis. The 64 embryos collected presented hypoplasia of the branchial arches or the snout in 79% of cases, auricular anomalies in 47% and ophthalmic anomalies in 12.5%. Fourteen NMRI mice on day 10.5 of gestation were treated with 1.5 mg (0.5 mg/kg) methyl-triazene (Methyl). The 126 embryos collected had developed a very high percentage of micromandibles and anomalies of both embryonic ears (94.6% to 100%). Finally, although the facial anomalies produced by retinoic acid resemble the human mandibulo-facial dysostosis syndrome, no correlation was found between hemicraniofacial microsomia and the administration of methyl-triazene.

Abnormalities, Drug-Induced↗
PubMed1998

Effects of irradiation on facial development in mouse embryos.

The purpose of this study was to observe the effects of irradiation on the craniofacial development of NMRI mouse embryos. Two populations of pregnant mice were irradiated with a single dose of 2 Gray on day 8 of gestation for the first population (Po. 1) and on day 9 of gestation for the second population (Po. 2). On gestational days 9 to 17, embryos were submitted to histological and scanning electron microscope examinations. The two populations of embryos presented a high percentage of centro-facial hypoplasia (74.7% for Po. 1 and 75% for Po. 2) which was more pronounced in the latter one. Ocular anomalies were present in 16% of the first population. Cases of anencephaly, cleft palate and anomalies of the central nervous system were found in both populations.

Abnormalities, Radiation-Induced↗
PubMed1998

Granulomatous vulvitis, granulomatous cheilitis: a single diagnosis?

We report two cases of labial swelling (oral and vulvar) with a granulomatous histology in patients with a history of Crohn's disease. The differential diagnosis of granulomatous vulvitis and cheilitis, as well as the symptomatology and treatment of vulvar and oral Crohn's disease are further discussed. To our knowledge, reported cases of vulvar and oral Crohn's disease are quite scarce in the literature, but the disease might be underdiagnosed. We hope to contribute to an earlier recognition and a better management of the vulvar and oral mucocutaneous lesions of Crohn's disease.

Adult↗
PubMed1998

Effects of irradiation and methyl-triazene on craniofacial development in mouse embryos: a semiautomated morphometric analysis.

OBJECTIVE: The purpose of the present study was a 2D-semiautomated morphometric analysis of craniofacial growth in nuclear magnetic resonance imaged (NMRI) mouse embryos. METHODS: The NMRI mouse embryos were exposed in utero to either a single dose of 2 Gy X-irradiation on day 9 of gestation (113 embryos) or to 1.5 mg methyl-triazene administered orally to their pregnant mothers on gestational day 10.5 (124 embryos). An additional group of 108 embryos was used as controls. Digitized pictures of embryos from gestational days 14 to 17 were taken in lateral right view using a video system. Landmarks were located and digitized for computerized analysis of growth changes in relation to developmental stages of the face. RESULTS: The results revealed that the snout of control embryos lengthens during the developmental period considered. The snout of embryos previously submitted to methyl-triazene displayed micrognathia, and all treated fetuses exhibited macroscopic signs of microcephaly with a reduced mandible. The snouts of irradiated embryos appeared shortened at the 14-day stage and continued to shorten as development proceeded. A shortening of the midface was detected macroscopically in 83% of the cases. CONCLUSION: The results of this morphometric analysis enabled us to trace the developmental progression of the induced dysmorphosis and to assess the differences compared with normal development.

Abnormalities, Drug-Induced↗
PubMed1998

[The role of apoptosis during craniofacial development: concepts and importance in pathology].

Apoptosis is an essential common final pathway in numerous pathological conditions such as malignant tumors, HIV-related CD4 lymphocytes degeneration, neurodegenerative disorders, and in programmed cell death events during normal embryogenesis. Some teratogenic substances for man and laboratory mammals induce an increase of the apoptotic phenomenon, responsible for the occurrence of some precise cranio-maxillo-facial malformations. The study of cell death during normal or teratogenic embryonic development allows to analyse the cellular mechanisms implied in the control of the apoptotic phenomenon, together with its dysregulation ending in pathological processes. We review the cell death phenomenon during cephalogenesis, both during normal embryogenesis, or in teratogenic conditions known to induce cranio-maxillo-facial malformations.

Abnormalities, Drug-Induced↗
PubMed1998

[Stress proteins: expression of a universal phenomenon of cell defense].

Heat shock proteins or stress proteins play a role in adaptative thermotolerance. All cells, procaryotic and eucaryotic, are able to respond to different cellular aggressions by the synthesis of these stress proteins. In normal physiological conditions, they are considered as "molecular chaperones" Their actual role in pathology is still unknown; some of these heat shock proteins may be correlated with the degree of aggressiveness of some tumors.

Adaptation, Physiological↗
PubMed1997

Strong expression of heat shock proteins in growth plate cartilage, an immunohistochemical study of HSP28, HSP70 and HSP110.

Heat shock proteins (HSPs) are known to be increased in response to stresses. Our immunohistochemical investigations revealed the strong expression of a wide range of HSPs in the chondrocytes of the tibial growth plate cartilage from young rats. HSP28 and HSP70 are expressed in the upper part of the hypertrophic zone of the growth plate cartilage. HSP110 are found from the proliferating zone to the hypertrophic zone. On the other hand, application of the TUNEL method has already shown apoptotic DNA fragmentation in the lower part of the proliferating zone. From then one, HSP expression in the chondrocytes may be correlated with apoptosis, but its possible relation with the different events occurring during the calcification process cannot be excluded.

Animals↗
PubMed1997

Myxomatous odontogenic tumor of the maxilla. An unusual case with squamous and mucoproducing epithelial component.

A tumor attached to the amelo-cemental junction of a third molar impacted in the maxillary tuberosity, consisted histologically of a myxomatous stroma, in which multicystic cavities lined by a columnar epithelium and mucoproducing cells, together with an aggressive squamous epithelial component were present. Although the diagnosis of polyp of the maxillary sinus cannot be excluded, this lesion most likely constitutes an unusual presentation for an odontogenic myxoma of the maxilla, in which an aggressive squamous epithelial component is present, along with a mucosecreting glandular component.

Adult↗
PubMed1996

Scanning electron microscopic and immunocytochemical studies of contraction during secondary CO2 laser wound healing in rat tongue mucosa.

An experimental model was established in which the decrease in surface area of CO2 laser wounds on rat tongues was measured during the healing process. Scanning electron microscopy was used to measure and delineate the outlines of the initial wounds and those of the residual wounds. A 50% decrease in the surface area of the wounds was observed 10 days after surgery during the healing process. At day 30, the scar surface area was less than 10% (7.4%) of the wound surface area at day 2. This contrasts with studies reported elsewhere where only minimal contraction was observed during the healing of CO2 laser wounds. Immunoperoxidase techniques revealed that three different phenotypes of myofibroblasts were present inside the healing area, expressing vimentin, actin and desmin. These persisted until day 30 after CO2 irradiation.

Actins↗
PubMed1996

Noma: clinical and evolutive aspect.

Noma is a gangrenous stomatitis affecting children from developing countries. It may leave dreadful mutilations around the mouth, leading to esthetic disabling sequels and permanent trismus. Iconography of the acute stage and of sequels is presented in this paper, and pathogenesis of the disease is discussed.

Adolescent↗