Transcriptional signatures of somatic neoblasts and germline cells in <i>Macrostomum lignano</i>

The regeneration-capable flatworm <i>Macrostomum lignano</i> is a powerful model organism to study the biology of stem cells in vivo. As a flatworm amenable to transgenesis, it complements the historically used planarian flatworm models, such as <i>Schmidtea mediterranea</i>. However, information on the transcriptome and markers of stem cells in <i>M. lignano</i> is limited. We generated a de novo transcriptome assembly and performed the first comprehensive characterization of gene expression in the proliferating cells of <i>M. lignano</i>, represented by somatic stem cells, called neoblasts, and germline cells. Knockdown of a selected set of neoblast genes, including <i>Mlig-ddx39</i>, <i>Mlig-rrm1</i>, <i>Mlig-rpa3</i>, <i>Mlig-cdk1</i>, and <i>Mlig-h2a</i>, confirmed their crucial role for the functionality of somatic neoblasts during homeostasis and regeneration. The generated <i>M. lignano</i> transcriptome assembly and gene expression signatures of somatic neoblasts and germline cells will be a valuable resource for future molecular studies in <i>M. lignano</i>

OBRA 1987 and the quality of nursing home care

Because minimum government standards for quality regulate only part of the market failure, they may have unintended effects. We present a general theory of how government regulation of quality of care may affect different market segments, and test the hypotheses for the nursing home market. OBRA 1987 was a sweeping government reform to improve the quality of nursing home care. We study how the effect of OBRA on the quality of nursing home care, measured by resident outcomes, varied with nursing home profitability. Using a semi-parametric method to control for the endogenous effects of regulation, we found that this landmark legislation had a negative effect on the quality of care in less profitable nursing homes, but improved the quality in more profitable nursing homes during the initial period after OBRA. But, this legislation had no statistically significant effect in the later period when the regulation was weakly enforced. Copyright Springer Science + Business Media, Inc. 2006Nursing home, Quality of care, Regulation,