In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.
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Question: Pluripotent stem cells exist in naive and primed states, epitomized by mouse embryonic stem cells (ESCs) and the developmentally more advanced epiblast stem cells (EpiSCs; ref. ). In the naive state of ESCs, the genome has an unusual open conformation and possesses a minimum of repressive epigenetic marks. In contrast, EpiSCs have activated the epigenetic machinery that supports differentiation towards the embryonic cell types. The transition from naive to primed pluripotency therefore represents a pivotal event in cellular differentiation. But the signals that control this fundamental differentiation step remain unclear. We show here that paracrine and autocrine Wnt signals are essential self-renewal factors for ESCs, and are required to inhibit their differentiation into EpiSCs. Moreover, we find that Wnt proteins in combination with the cytokine LIF are sufficient to support ESC self-renewal in the absence of any undefined factors, and support the derivation of new ESC lines, including ones from non-permissive mouse strains. Our results not only demonstrate that Wnt signals regulate the naive-to-primed pluripotency transition, but also identify Wnt as an essential and limiting ESC self-renewal factor.

Answer: Embryonic stem cells require Wnt proteins to prevent differentiation to epiblast stem cells

Question: Werner's syndrome (WS) and Bloom's syndrome (BS) are cancer predisposition disorders caused by loss of function of the RecQ helicases WRN or BLM, respectively. BS and WS are characterized by replication defects, hyperrecombination events and chromosomal aberrations, which are hallmarks of cancer. Inefficient replication of the G-rich telomeric strand contributes to chromosome aberrations in WS cells, demonstrating a link between WRN, telomeres and genomic stability. Herein, we provide evidence that BLM also contributes to chromosome-end maintenance. Telomere defects (TDs) are observed in BLM-deficient cells at an elevated frequency, which is similar to cells lacking a functional WRN helicase. Loss of both helicases exacerbates TDs and chromosome aberrations, indicating that BLM and WRN function independently in telomere maintenance. BLM localization, particularly its recruitment to telomeres, changes in response to replication dysfunction, such as in WRN-deficient cells or after aphidicolin treatment. Exposure to replication challenge causes an increase in decatenated deoxyribonucleic acid (DNA) structures and late-replicating intermediates (LRIs), which are visible as BLM-covered ultra-fine bridges (UFBs) in anaphase. A subset of UFBs originates from telomeric DNA and their frequency correlates with telomere replication defects. We propose that the BLM complex contributes to telomere maintenance through its activity in resolving LRIs.

Answer: The BLM helicase contributes to telomere maintenance through processing of late-replicating intermediate structures

Question: The ecologic study design is routinely used by epidemiologists in spite of its limitations. It is presently unknown how well the challenges of the design are dealt with in epidemiologic research. The purpose of this bibliometric review was to critically evaluate the characteristics, statistical methods, and reporting of results of modern cross-sectional ecologic papers. A search through 6 major epidemiology journals identified all cross-sectional ecologic studies published since January 1, 2000. A total of 125 articles met the inclusion requirements and were assessed via common evaluative criteria. It was found that a considerable number of cross-sectional ecologic studies use unreliable methods or contain statistical oversights; most investigators who adjusted their outcomes for age or sex did so improperly (64%), statistical validity was a potential issue for 20% of regression models, and simple linear regression was the most common analytic approach (31%). Many authors omitted important information when discussing the ecologic nature of their study (31%), the choice of study design (58%), and the susceptibility of their research to the ecological fallacy (49%). These results suggest that there is a need for an international set of guidelines that standardizes reporting on ecologic studies. Additionally, greater attention should be given to the relevant biostatistical literature.

Answer:
The quality of modern cross-sectional ecologic studies: a bibliometric review.