The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue-nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allele-specific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.

Tissue engineering and cell therapy require large-scale production of homogeneous populations of lineage-restricted progenitor cells that easily can be induced to differentiate into a specific tissue. We have developed straightforward protocols for the establishment of human embryonic stem (hES) cell-derived mesenchymal progenitor (hES-MP) cell lines. The reproducibility was proven by derivation of multiple hES-MP cell lines from 10 different hES cell lines. To illustrate clinical applicability, a xeno-free hES-MP cell line was also derived. None of the markers characteristic for undifferentiated hES cells were detected in the hES-MP cells. Instead, these cells were highly similar to mesenchymal stem cells with regard to morphology and expression of markers. The safety of hES-MP cells following transplantation was studied in severely combined immunodeficient (SCID) mice. The implanted hES-MP cells gave rise to homogeneous, well-differentiated tissues exclusively of mesenchymal origin and no teratoma formation was observed. These cells further have the potential to differentiate toward the osteogenic, adipogenic, and chondrogenic lineages in vitro. The possibility of easily and reproducibly generating highly expandable hES-MP cell lines from well-characterized hES cell lines with differentiation potential into several mesodermal tissues entails an enormous potential for the field of regenerative medicine.

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The present study tested the impact of attention training on cognition; secondary appraisal of perceived stress, and on metacognition; meta-worry in stressed students. Theoretically derived from the Self-Regulatory Executive Function model (S-REF model; Wells and Matthews, 1994a , 1996 ), the attention training technique (ATT; Wells, 1990 ) is intended to promote flexible, voluntary external attention and has been shown to reduce symptoms of psychological distress. The present experimental study explored the effects of ATT on cognitive and metacognitive levels of appraisal, namely perceived stress (primary outcome) and meta-worry (secondary outcome). Stressed students were randomized to an experimental ATT group ( n = 23) or a control group ( n = 23). The ATT group attended an initial training session followed by 4 weeks of individual (12 min) daily ATT practice. The control group waited for 4 weeks before receiving the intervention. The outcomes were scores on the Perceived Stress Scale 14 (PSS-14) and the Meta-Worry Questionnaire (MWQ) frequency and belief subscales at post study. Both measures decreased significantly following ATT with large pre- to post- effect sizes but there were minimal changes in the control group. The between-group differences were statistically significant. The results add to the literature on the potential effects of ATT by demonstrating effects on the content of cognitive stress appraisals and on meta-worry in an academic setting in a stressed student sample.