Philippe Daelemans

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.

S100A8 and S100A9 calcium-binding proteins: localization within normal and cyclosporin A-induced overgrowth gingiva.

S100A8 and S100A9, also called myeloid related protein (MRP) 8 and 14, are calcium-binding proteins highly expressed in neutrophils, in which they play a key role in the inflammatory progression. In this study, we looked at the expression of S100A8/A9 within gingiva from normal and Cyclosporin A (CsA)-induced overgrowth gingiva. In gingiva from the CsA group, several positive S100A8/A9 cells were seen within the connective tissue, whereas in normal gingiva very few positive S100A8/A9 cells were detected. These cells correspond either to activated macrophages or to neutrophils, reflecting the well-known gingival inflammatory status associated with the CsA-treated group. In addition, in both the normal and drug-treated group, the gingival epithelia appeared S100A8/A9 immunopositive. More specifically, S100A8/A9 appeared in the majority within the spinocellular layer and located extracellularly within the desmosomes. In addition, S100A8/A9 also appeared sporadically intracellularly, located within the cytoplasm and the nuclei, reflecting S100A8/A9 translocations.

Bisphosphonates et ostéo(chimio)nécrose maxillo-mandibulaire

Introduction Les osteonecroses maxillo-mandibulaires sont exceptionnelles en dehors du contexte d’une radiotherapie cervico-faciale. Les bisphosphonates sont des analogues non metabolises de pyrophosphates. Ils menent a l’inhibition de l’activite osteoclastique et sont prescrits dans le traitement de l’hypercalcemie associee aux processus tumoraux, dans le traitement des metastases osteolytiques, dans la maladie de Paget et dans l’osteoporose. L’incidence des osteonecroses maxillo-mandibulaires sur prise de bisphosphonates est de 1/10 000 patients, mais elle est probablement sous-estimee par manque d’examens bucco-dentaires chez les patients traites. Materiel et methodes Nous decrivons six cas de necrose mandibulaire associee a la prise de bisphosphonates, cinq dans un contexte de tumeurs malignes, un cas dans le cadre du traitement de l’osteoporose. Resultats L’apparition de l’osteonecrose a ete spontanee chez deux patients ; elle faisait suite a une extraction dentaire chez deux autres. Il preexistait, chez les deux derniers, un foyer infectieux dentaire. Le delai d’apparition de l’osteonecrose a varie de 1 a 6 ans. Toutes les biopsies etaient colonisees par de l’actinomycose. Discussion La predisposition a la necrose maxillo-mandibulaire semble s’expliquer par l’exposition de l’os dans la cavite buccale. La symptomatologie va de la gene localisee au sequestre osseux avec fracture. Le traitement est essentiellement conservateur. Une mise en etat bucco-dentaire avant tout traitement par bisphosphonates est recommandee.