Expression of Msx1 and Dlx1 during Dumbo rat head development: Correlation with morphological features

The Dumbo rat possesses some characteristics that evoke several human syndromes, such as Treacher-Collins: shortness of the maxillary, zygomatic and mandibular bones, and low position of the ears. Knowing that many homeobox genes are candidates in craniofacial development, we investigated the involvement of the Msx1 and Dlx1 genes in the Dumbo phenotype with the aim of understanding their possible role in abnormal craniofacial morphogenesis and examining the possibility of using Dumbo rat as an experimental model for understanding abnormal craniofacial development. We studied the expression of these genes during craniofacial morphogenesis by RT-PCR method. We used Dumbo embryos at E12 and E14 and included the Wistar strain as a control. Semi-quantitative PCR analysis demonstrated that Msx1 and Dlx1 are expressed differently between Dumbo and Wistar rats, indicating that their low expression may underly the Dumbo phenotype

The Molecular Chaperone Hsp90α Is Required for Meiotic Progression of Spermatocytes beyond Pachytene in the Mouse

The molecular chaperone Hsp90 has been found to be essential for viability in all tested eukaryotes, from the budding yeast to Drosophila. In mammals, two genes encode the two highly similar and functionally largely redundant isoforms Hsp90α and Hsp90β. Although they are co-expressed in most if not all cells, their relative levels vary between tissues and during development. Since mouse embryos lacking Hsp90β die at implantation, and despite the fact that Hsp90 inhibitors being tested as anti-cancer agents are relatively well tolerated, the organismic functions of Hsp90 in mammals remain largely unknown. We have generated mouse lines carrying gene trap insertions in the Hsp90α gene to investigate the global functions of this isoform. Surprisingly, mice without Hsp90α are apparently normal, with one major exception. Mutant male mice, whose Hsp90β levels are unchanged, are sterile because of a complete failure to produce sperm. While the development of the male reproductive system appears to be normal, spermatogenesis arrests specifically at the pachytene stage of meiosis I. Over time, the number of spermatocytes and the levels of the meiotic regulators and Hsp90 interactors Hsp70-2, NASP and Cdc2 are reduced. We speculate that Hsp90α may be required to maintain and to activate these regulators and/or to disassemble the synaptonemal complex that holds homologous chromosomes together. The link between fertility and Hsp90 is further supported by our finding that an Hsp90 inhibitor that can cross the blood-testis barrier can partially phenocopy the genetic defects

Benefits of using a Trainer T4K

The aim of this study was to observe the effects of treatment with a Trainer T4K® myofunc tional appliance of thirteen late mixed dentition patients. We conducted thorough clinical examinations that included assessment of breathing and swallowing capabilities and took profile cephalograms and study models for each one. We also selected a control group that had been treated only with palatal expansion so that we could distinguish the effects of myofunctional therapy from those of expansion. We observed significant mandibular growth (p<0.05) of 3.24 mm on the average and a significant decrease in overjet, essentially linked to dento-alveolar effects, in the Trainer T4K® group. Swallowing and breathing function also improved in these patients. The two groups had similar maxillary and mandibular expansion. So we conclude that use of a Trainer T4K® myofunctional appliance results in improved antero-postero dental relationships and an improvement in oral functioning

Intérêt du port d’une gouttière myofonctionnelle, Trainer T4K

Les effets d’un traitement par gouttière myofonctionnelle de type Trainer T4K®, à la suite d’une expansion palatine, ont été observés chez 13 patients en denture mixte tardive. Des mesures sur téléradiographies de profil, sur moulages et des données cliniques sur la respiration et la déglutition ont été relevées. Un groupe de contrôle, ayant bénéficié d’une disjonction seule, a permis de différencier les effets de disjonction de ceux de la gouttière. On a pu observer dans le groupe Trainer T4K® : une avancée mandibulaire significative (p<0,05) en moyenne de 3,24 mm et une diminution significative du surplomb incisif, liée notamment à des effets dento-alvéolaires. Les fonctions ont été améliorées. Par ailleurs, nous avons constaté une expansion maxillaire et mandibulaire, identiques dans les 2 groupes. Selon nos observations, le Trainer T4K® permettrait d’obtenir une correction sagittale ainsi qu’une amélioration des dysfonctions

Étude immuno-histochimique de l'expression des protéines Dlx1 et Msx1 durant la céphalogenèse des rats Wistar et Dumbo Corrélation avec les données morphologiques.

The Dumbo rat is characterized by a short snout, low ears and relative hypoplasia of maxillar and zygomatic bones. It corresponds to an autosomal recessive genotype. Previous study demonstrated a global deficit of Dlx1 and Msx1 genes expression in comparison to Wistar embryos as considered as control animals. We performed a histological study of cephalic development of Dumbo rats compared to Wistar embryos and an immunohistochemical analysis of Dlx1 and Msx1 protein expression during cephalogenesis. Our data indicate that the pattern of expression of both genes is similar in both strains, but that quantitative differences in gene expression can be the result of delayed organogenesis in Dumbo rat in comparison to Wistar. Some data about gene expressions are discussed at the light of the postulated function of Dlx1 and Msx1 in cephalic development.Comparative StudyEnglish AbstractJournal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe