Currently, adult stem cells are attracting significant interest in regenerative medicine and tissue engineering. These cells have been isolated from various tissue sources; however, in most cases, adult stem cells useful for tissue engineering and regeneration are present at a low frequency. High numbers of stem cells with an effective and reliable potential for differentiation are needed for clinical applications. Thus, the identification of new stem cell sources and the establishment of optimized cell culture conditions that allow for the amplification of stem cells are of utmost relevance. In addition, the isolation procedure should ideally be minimally invasive and possibly be performed under local anesthesia. We report here for the first time on the identification of adult stem cells with mesenchymal characteristics in human parotid gland tissue. Cells were isolated from freshly resected specimens of parotid glands using enzymatic digestion and plastic adhesion protocols. Following an initial proliferation period and short-term culture for four passages, immunophenotyping revealed the presence of mesenchymal stem cell markers. In the presence of tissue-specificinduction medium, stem cells could be differentiated into adipogenic, osteogenic, and chondrogenic cell types. Tissue-specific differentiation was confirmed by histochemical and immunocytochemical staining as well as by RT-PCR for defined marker genes. This study is, to the best of our knowledge, the first report on the isolation and differentiation of stem cells from adult human parotid glands. Although isolated from an endodermal tissue source, these stem cells share many characteristics with MSCs. Easy accessibility and a high differentiation potential make salivary gland-derived stem cells a promising source for future applications in regenerative medicine.

With the increasing relevance of cell-based therapies, there is a demand for cell-labeling techniques for in vitro and in vivo studies. For the reasonable tracking of transplanted stem cells in animal models, the usage of quantum dots (QDs) for sensitive cellular imaging has major advances. QDs could be delivered to the cytoplasm of the cells providing intense and stable fluorescence. Although QDs are emerging as favourable nanoparticles for bioimaging, substantial investigations are still required to consider their application for adult stem cells. Therefore, rat pancreatic stem cells (PSCs) were labeled with different concentrations of CdSe quantum dots (Qtracker 605 nanocrystals). The QD labeled PSCs showed normal proliferation and their usual spontaneous differentiation potential in vitro. The labeling of the cell population was concentration dependent, with increasing cell load from 5 nM QDs to 20 nM QDs. With time-lapse microscopy, we observed that the transmission of the QD particles during cell divisions was random, appearing as equal or unequal transmission to daughter cells. We report here that QDs offered an efficient and nontoxic way to label pancreatic stem cells without genetic modifications. In summary, QD nanocrystals are a promising tool for stem cell labeling and facilitate tracking of transplanted cells in animal models.

L’objectif de cet article est de se demander si la filière aurifère légale en Guyane française peut servir les objectifs du développement durable. En effet, cette filière est en proie à des difficultés : alors que les cours de l’or sont en constante augmentation, le nombre d’opérateurs miniers diminue constamment, depuis près de sept ans. Ce paradoxe aurifère guyanais trouve ses origines dans la volonté étatique française d'organiser la filière et d'en faire un exemple en matière de « durabilité », volonté clairement exprimée à la suite du Grenelle de l’Environnement. Principalement élaboré à partir d’entretiens semi-directifs et d’archives, l’article a notamment cherché à analyser les principaux éléments de cette structuration, le schéma départemental d’orientation minière (SDOM), en cours d’adoption, et plusieurs initiatives destinées à améliorer les pratiques des opérateurs miniers qui sont majoritairement des artisans. Toutefois, cette évolution révèle des antagonismes entre les parties prenantes (collectivités territoriales, services de l'État, opérateurs miniers et environnementalistes). Ces derniers ont fait surface lors de l’affaire du Camp Caïman, impliquant la multinationale Iamgold, et pendant le processus d’élaboration du SDOM lui-même. Des problématiques connexes telles que les revendications locales de gestion de la ressource aurifère, mais aussi et surtout l’orpaillage illégal, dressent des perspectives d’avenir plutôt incertaines pour la filière aurifère.

Xerostomia as a side effect of radiotherapy or due to Sjögren's disease leads to considerable impairment of the quality of life of the affected patients. Preventive treatment approaches such as intensity-modulated radiotherapy, surgical transfer of a submandibular gland to a site outside the radiation field or administration of amifostin during radiation treatment are not yet completely established in clinical practice and are not applicable for all patients. Symptomatic treatment with pilocarpin or synthetic saliva leads to an improvement of the symptoms only in some patients, and in the case of pilocarpin significant systemic anticholinergic side-effects might occur. Because large numbers of patients are affected and current treatment options are not satisfactory, it is essential to develop new treatment options. In parallel with the in vitro production of functional salivary gland constructs by means of tissue engineering techniques, attempts are currently under way to experimentally restore salivary gland function by genetic treatment approaches such as transfection of the affected salivary glands with aquaporins or pro-angiogenic factors. In addition, the in vivo application of stem cells is under investigation. In the present paper, we discuss the clinical and radiobiological background of xerostomia and highlight possible innovative future treatment options.