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How blood is made redefined

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From ScienceDaily:

Stem-cell scientists redefine how blood is made, toppling conventional ‘textbook’ view

The findings, published online in the journal Science, prove “that the whole classic ‘textbook’ view we thought we knew doesn’t actually even exist,” says principal investigator John Dick, Senior Scientist at Princess Margaret Cancer Centre, University Health Network (UHN), and Professor in the Department of Molecular Genetics, University of Toronto.

“Instead, through a series of experiments we have been able to finally resolve how different kinds of blood cells form quickly from the stem cell — the most potent blood cell in the system — and not further downstream as has been traditionally thought,” says Dr. Dick, who holds a Canada Research Chair in Stem Cell Biology and is also Director of the Cancer Stem Cell Program at the Ontario Institute for Cancer Research. He talks about the research at www.youtu.be/D08FMKDppVQ .

The research also topples the textbook view that the blood development system is stable once formed. Not so, says Dr. Dick. “Our findings show that the blood system is two-tiered and changes between early human development and adulthood.”


In short, it is all more complex than thought. All just happened by accident, though, right?

Wow, so much is changing. What a time to front some dude from the 19th century as having single greatest idea anyone ever had, and Origin of Species as the most influential academic book.

Zachriel, Bimbette, from Airhead TV, is on Line 2, and well, she’s just really confused and wants to talk to you. Looking earnest and concerned about people who doubt Top Ideas isn’t working for her like it used to.

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All just happened by accident, though, right?
But also it took some time to evolve to the current level of complex complexity. Always remember the time term in the magic formula: RM + NS + EG + HGT + (...)* + T -> bingo! :) The "time" factor is very important. Insufficient, but necessary. Our beloved friend gpuccio reminded that to me recently, when he wrote that it takes time to understand exactly how the biological procedures work. I think gpuccio didn't mean that he's trying to understand how those procedures got implemented to begin with. It seems to me that he's only concerned, at least at this point, about how they operate and where they are stored. But I could be wrong. (...)* reserved for new terms that might be added in the future, so that the magic formula remains compatible with scientific evidence. :) Dionisio
The U of T Faculty Club has a nice lunchroom in the basement.
Ah! How nice! Now this makes me struggle with a strong temptation to envy. :( Maybe I could apply for work in that basement lunchroom, doing something like cleaning tables, and have an opportunity to meet some of those scientists? Wow! Alright, I better stop daydreaming. :) Anyway, it's nice to know the distinguished Canadian guest here can talk to those scientists directly. That's really cool! :) Dionisio
Hematopoiesis is a process capable of generating up to 300 million cells per minute in the bone marrow of an adult human. All these cells arise from multipotent hematopoietic stem cells (HSCs). Continuous blood cell production for life is achieved by balancing self-renewal and differentiation among proliferating HSCs. This inner balance between self-renewal and lineage commitment is tightly controlled by integrating intrinsic and extrinsic mechanisms that govern the HSC state, which are still currently ambiguous.
miR-17 promotes expansion and adhesion of human cord blood CD34 + cells in vitro Yuxia Yang1, Saifeng Wang2, Zhenchuan Miao3, Wei Ma4, Yanju Zhang5, Li Su6, Mengyu Hu1, Junhua Zou1, Yuxin Yin2* and Jianyuan Luo17* Stem Cell Research & Therapy 2015, 6:168 doi:10.1186/s13287-015-0159-1 http://www.stemcellres.com/content/6/1/168
Complex complexity. Dionisio
Dionisio at 2: The U of T Faculty Club has a nice lunchroom in the basement. ;) News
In a classical view of hematopoiesis, the various blood cell lineages arise via a hierarchical scheme starting with multipotent stem cells that become increasingly restricted in their differentiation potential through oligopotent and then unipotent progenitors. We developed a cell-sorting scheme to resolve myeloid (My), erythroid (Er), and megakaryocytic (Mk) fates from single CD34+ cells and then mapped the progenitor hierarchy across human development. Fetal liver contained large numbers of distinct oligopotent progenitors with intermingled My, Er, and Mk fates. However, few oligopotent progenitor intermediates were present in the adult bone marrow. Instead only two progenitor classes predominate, multipotent and unipotent, with Er-Mk lineages emerging from multipotent cells. The developmental shift to an adult “two-tier” hierarchy challenges current dogma and provides a revised framework to understand normal and disease states of human hematopoiesis.
Distinct routes of lineage development reshape the human blood hierarchy across ontogeny Faiyaz Notta1,2,*,†, Sasan Zandi1,2,*, Naoya Takayama1,2, Stephanie Dobson1,2, Olga I. Gan1, Gavin Wilson2,4, Kerstin B. Kaufmann1,2, Jessica McLeod1, Elisa Laurenti6, Cyrille F. Dunant7, John D. McPherson3,4, Lincoln D. Stein2,4, Yigal Dror5, John E. Dick1,2,‡ Author Affiliations 1Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada. 2Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada. 3Medical Biophysics, University of Toronto, Toronto, Ontario, Canada. 4Ontario Institute for Cancer Research, Toronto, Ontario, Canada. 5The Hospital for Sick Children Research Institute, University of Toronto, Ontario, Canada. 6Wellcome Trust, Medical Research Council Cambridge Stem Cell Institute, Department of Haematology, University of Cambridge, Cambridge, UK. 7Ecole Polytechnique Fédérale de Lausanne, LMC, Station 12, Lausanne, CH-1015, Switzerland Author Notes ?† Present address: Ontario Institute for Cancer Research, Toronto, Ontario, Canada. ?‡Corresponding author. E-mail: jdick@uhnres.utoronto.ca ?* These authors contributed equally to this work. Science DOI: 10.1126/science.aab2116 http://www.sciencemag.org/content/early/2015/11/04/science.aab2116
University of Toronto? Is that the same place where a distinguished guest in this blog works in? Would it be possible that the distinguished guest could talk to some of these authors directly? That's cool, isn't it? :) Dionisio
In short, it is all more complex than thought.
Complex complexity. Work in progress... stay tuned. Dionisio

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