1+2/2010 - Společnost pro pojivové tkáně

developing teeth of mice. The murine incisorscontain a stem cell riche at its epithelialcompartment that allows the incessantgrowth and eruption of this tooth. Sincehuman teeth are not perpetually growing,murine incisors provide an excellentmodel for the study of dental stem cells.In order to assesss the role of Jagged1 in tooth development and homeostasis,we have used mutant mice that were specificallydeleted for JAGGED 1 in epithelialcells (Keratin 14 Cre).These mice display a faint delay inthe development of mandibular incisors.Ast the level of molars, we could observee delay in enamel production at postnatalday 2. Furthermore, a palatal defectresembling the human Torus palatinus hasalso been detected in both keratin 14 andkeratin 5 induced Jagged 1 mutants. Finally,the proliferation of osteoblasts precursorsisolated from bone marrow was increased.The absence of Jagged 1 in epithelialcells leads to faint aberrations in toothdevelopment and eruption. The fact thatboth incisors and molars are affected inthe mutant mice suggests that Jagged 1could provide crucial signals for the maintenanceof fully functional dental progenitors.Furthermore, since mesenchymalcells such as osteoblasts are affected bythe absence of JAGGED 1 in epithelial cells,we hypothesize that bone marrow mesenchymalprogenitors are dependent uponearly NOTCH – JAGGED 1 signals. Thesesignals are derived from epithelial cellsadjacent to the mesenchyme and shouldregulate proliferation and differentition/commitent of mesenchymal cells.Poznámky: JAGGED gen 1 mutovanýmá vztah k defektům kostí a zubů, má vztahk ameloblastům., Dále jsou ve hře receptorovégeny NOTCH a ligandy NOTCHkteré mají vztah k defektům kostí a zubů.Receptorové geny NOTCH se podobajíreceptorům EGF. Notochordové geny majívztah k pravolevé asymetrii, ExpreseNOTCH ovlivňuje vývoj zubů. RozlišujemeNOTCH 1,2 a 3 geny.JAGGD geny mají vztah k syndromologii,k některým vrozeným srdečnímvadám, jejich mutace se uplatňují u poruchsomitogeneze a axiálního skeletu. JAGDgeny mají vztah k mandibule, mutaceJAGD 1 ovlivňují rozdílnost ve vývoji mandibulyu různých jedinců.Geny JAGD 1 ovlivňují materiálovévlastnosti tvrdých zubních tkání a otěrskloviny. Je prokázána defektní produkceskloviny u JAGD 1 genu. Mutace JAGDse uplatňují i u poruch erupce zubů, dáleu poruch mineralizace, kde docházík značnému otěru zubů.COMPARATIVE EFFECTS OFCYCLOSPORINE, TACROLIMUSAND RAPAMYCIN ON BONEMINERAL DE4NSITY AND BONEMICROSTRUCTURE IN HEALTHYADULT RATSM. Rubert et al. (Madrid, Santiago de Compostela,Ourense – Španělsko)One of the factors which can contributeto the severe bone loss after transplantationis the direct action of immunosupressiveagents on bone cells. The aim of thiswork was to study the effects producedcyclosporine (CsA), tacrolimus (FK 506)and rapamycin (RAPA) on bone mass andmicrostructure when they are administeredto male healthy adult rats.The administration of CsA to healthmale rats did not generate detectablechanges in neither BMD nor femoral tra-POHYBOVÉ ÚSTROJÍ, ročník 17, 2010, č. 1+2 117