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Mutations Extending Lifespan Induce Expression Of Germline Genes In Somatic Cells
In the sense that organisms existing today are connected through a chain of life - through their parents, grandparents and other ancestors - almost a billion years back to the first animals of the pre-Cambrian era, an animal"s reproductive cells can be considered to be immortal. These germline cells generate their offspring"s somatic cells - other cells involved in all aspects of growth, metabolism and behavior, which have a set lifespan - and new germline cells that continue on, generation after generation.
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AAMC Applauds Benjamin As Choice For Surgeon General, USA
AAMC (Association of American Medical Colleges) President and CEO Darrell G. Kirch, M.D., issued the following statement on President Obama"s nomination of Regina Benjamin, M.D., M.B.A., as U.S. surgeon general:
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Carbohydrate Acts As Tumor Suppressor
Scientists at Burnham Institute for Medical Research (Burnham) have discovered that specialized complex sugar molecules (glycans) that anchor cells into place act as tumor suppressors in breast and prostate cancers. These glycans play a critical role in cell adhesion in normal cells, and their decrease or loss leads to increased cell migration by invasive cancer cells and metastasis. An increase in expression of the enzyme that produces these glycans, í²3GnT1, resulted in a significant reduction in tumor activity. The research was published in the journal Proceedings of the National Academy of Sciences.
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Environmental Factors Instruct Lineage Choice Of Blood Progenitor Cells

The research team led by Dr. Timm Schroeder, stem cell researcher at Helmholtz Zentrum MÃønchen, has developed a new bioimaging method for observing the differentiation of hematopoietic progenitor cells (HPC) at the single-cell level. With this method the researchers were able to prove for the first time that not only cell-intrinsic mechanisms, but also external environmental factors such as growth factors can control HPC lineage choice directly. The findings, published in the current issue of the prestigious journal Science, provide an essential building block for understanding the molecular mechanisms of hematopoiesis and are an important prerequisite for optimizing therapeutic stem cell applications. For decades scientists from various disciplines have discussed to what respective extent genetic predisposition and environmental factors influence human development. Likewise, the same "nature vs. nurture" issue is debated by hematologists and stem cell researchers: Is multipotent progenitor cell differentiation influenced solely by cell-intrinsic mechanisms or is it also influenced by the environment of the cell? What role do growth factors such as cytokines play? Do they influence HPC lineage choice directly or do they merely regulate the survival of the cell after the lineage choice has been made? Despite the immense importance of cytokines for day-to-day clinical research - and not least their far-reaching significance commercially - this issue has been one of the key unknown factors in the stem cell biology of blood. "This is simply because until now we did not have the suitable technology to observe the processes of cell differentiation and to measure them quantitatively," explained Dr. Timm Schroeder, research group leader at the Institute of Stem Cell Research of Helmholtz Zentrum MÃønchen. "We didn"t know exactly what happens during this time span," Dr. Schroeder said. "That is why until now we could not prove what role cytokines play." With the new bioimaging techniques developed by Dr. Schroeder"s team, progenitor cells could be observed for a longer period and on the single-cell level. Depending on the kind of cytokines present, after a few days the HPC cultures contained only one cell type. The question remained unanswered whether this was a consequence of direct cytokine regulation or merely the result of sorting out "erroneously differentiated" cells by cell death. Using the new bioimaging techniques for continuous single-cell observation, Dr. Michael Rieger and students in Dr. Schroeder"s research group showed for the first time that no cell death could be detected during the entire cell differentiation process. This proves unambiguously that HPC lineage choices can be steered by external environmental factors such as in this case by cytokines. The hematopoietic progenitor cells are "instructed" by cytokines. "These findings confirm that signaling pathways that are activated by cytokine receptors influence the lineage choices of the cells," Dr. Schroeder said. "The new method offers us the unique chance to observe the effect of all the molecules involved in the differentiation process separately and to better understand their role. This is an important requirement for optimizing the therapeutic use of stem cells." Further information Original publication: Rieger MA, Hoppe PS, Smejkal BM, Eitelhuber AC & Schroeder T (2009): Hematopoietic cytokines can instruct lineage choice. Science 325:217-218 Sven Winkler Helmholtz Zentrum MÃønchen - German Research Center for Environmental Health


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