Induction and selection of Sox17-expressing endoderm cells generated from murine embryonic stem cells.

Embryonic stem (ES) cells offer a valuable source for generating insulin-producing cells. However, current differentiation protocols often result in heterogeneous cell populations of various developmental stages. Here we show the activin A-induced differentiation of mouse ES cells carrying a homologous dsRed-IRES-puromycin knock-in within the Sox17 locus into the endoderm lineage. Sox17-expressing cells were selected by fluorescence-assisted cell sorting (FACS) and characterized at the transcript and protein level. Treatment of ES cells with high concentrations of activin A for 10 days resulted in up to 19% Sox17-positive cells selected by FACS. Isolated Sox17-positive cells were characterized by defini- tive endoderm-specific Sox17/Cxcr4/Foxa2 transcripts, but lacked pluripotency-associated Oct4 mRNA and protein. The Sox17-expressing cells showed downregulation of extraembryonic endoderm (Sox7, Afp, Sdf1)-, mesoderm (Foxf1, Meox1)- and ectoderm (Pax6, NeuroD6)-specific transcripts. The presence of Hnf4α, Hes1 and Pdx1 mRNA demonstrated the expression of primitive gut/foregut cell-specific markers. Ngn3, Nkx6.1 and Nkx2.2 transcripts in Sox17-positive cells were determined as properties of pancreatic endocrine progenitors. Immunocytochemistry of activin A-induced Sox17-positive embryoid bodies revealed coexpression of Cxcr4 and Foxa2. Moreover, the histochemical demonstration of E-cadherin-, Cxcr4-, Sox9-, Hnf1ß- and Ngn3-positive epithelial-like structures underlined the potential of Sox17-positive cells to further differentiate into the pancreatic lineage. By reducing the heterogeneity of the ES cell progeny, Sox17-expressing cells are a suitable model to evaluate the effects of growth and differentiation factors and of culture conditions to delineate the differentiation process for the generation of pancreatic cells in vitro.

Measurements using orthodontic analysis software on digital models obtained by 3D scans of plaster casts : Intrarater reliability and validity.

OBJECTIVE: The purpose of this work was to determine the reliability and validity of measurements performed on digital models with a desktop scanner and analysis software in comparison with measurements performed manually on conventional plaster casts. MATERIALS AND METHODS: A total of 20 pairs of plaster casts reflecting the intraoral conditions of 20 fully dentate individuals were digitized using a three-dimensional scanner (D700; 3Shape). A series of defined parameters were measured both on the resultant digital models with analysis software (Ortho Analyzer; 3Shape) and on the original plaster casts with a digital caliper (Digimatic CD-15DCX; Mitutoyo). Both measurement series were repeated twice and analyzed for intrarater reliability based on intraclass correlation coefficients (ICCs). The results from the digital models were evaluated for their validity against the casts by calculating mean-value differences and associated 95 % limits of agreement (Bland-Altman method). Statistically significant differences were identified via a paired t test. RESULTS: Significant differences were obtained for 16 of 24 tooth-width measurements, for 2 of 5 sites of contact-point displacement in the mandibular anterior segment, for overbite, for maxillary intermolar distance, for Little's irregularity index, and for the summation indices of maxillary and mandibular incisor width. Overall, however, both the mean differences between the results obtained on the digital models versus on the plaster casts and the dispersion ranges associated with these differences suggest that the deviations incurred by the digital measuring technique are not clinically significant. CONCLUSION: Digital models are adequately reproducible and valid to be employed for routine measurements in orthodontic practice.

Orthodontic treatment need in a representative adult cohort.

BACKGROUND AND OBJECTIVE: There is currently no representative information for central Germany on the prevalence of dental malalignments and jaw discrepancies in permanent dentition. The aim of this study was to describe the extent of tooth and jaw malformations in a representative adult population according to conventional orthodontic indices. SUBJECTS AND METHODS: Three dimensionally (3D)-oriented study casts were measured from a representative sample of adults from the Halle and Leipzig urban areas consisting of 102 men and 143 women aged between 18 and 39 years, yielding a total of 245 volunteers. The index values we determined were the Index of Orthodontic Treatment Need (IOTN), the German Orthodontic Indication Groups (OIG) and the Occlusal Index (OI). The descriptive evaluation of the data and group comparisons (U test, chi(2) test) were performed with SPSS® 13.0. RESULTS: More than half of the adults we examined were assessed as needing treatment according to the IOTN (61.6%), the German OIG (59.6%) and the OI (58.4%; intermediate severity = 5.92). We observed no significant differences in age or gender. CONCLUSION: This is the first time that the prevalence of orthodontic findings has been documented for the central German area in a cohort representative of the population. Our results reveal a great need for therapy. As the classifications describe different patient groups, the individual need for treatment is inadequately documented.