Question: Benjamin Alman, MD, FRCSC, was the head of the division of Orthopedic surgery at the Hospital for Sick Children in Toronto, Ontario, senior scientist in developmental and stem cells scientific study of undifferentiated biological cells, that can differentiate into specialized cells and can divide (through which scientific process) to produce more duplicates?

Context paragraphs:
Stem cell genomics: Stem cell genomics analyzes the genomes of stem cells.  Currently, this field is rapidly expanding due to the dramatic decrease in the cost of sequencing genomes.  The study of stem cell genomics has wide reaching implications in the study of stem cell biology and possible therapeutic usages of stem cells.  Application of research in this field could lead to drug discovery and information on diseases by the molecular characterization of the pluripotent stem cell through DNA and transcriptome sequencing and looking at the epigenetic changes of stem cells and subsequent products.  One step in that process is single cell phenotypic analysis, and the connection between the phenotype and genotype of specific stem cells.  While current genomic screens are done with entire populations of cells, focusing in on a single stem cell will help determine specific signaling activity associated with varying degrees of stem cell differentiation and limit background due to heterogeneous populations.  Single cell analysis of induced pluripotent stem cells (iPSCs), or stem cells able to differentiate into many different cell types, is a suggested method for treating such diseases like Alzheimer's disease (AD).  This includes for understanding the differences between sporadic AD and familial AD.  By first taking a skin sample from the patient and are transformed by transducing cells using retroviruses to encode such stem cell genes as Oct4, Sox2, KLF4 and cMYC.  This allows for skin cells to be reprogrammed into patient-specific stem cell lines.  Taking genomic sequences of these individual cells would allow for patient-specific treatments and furthering understanding of AD disease models.  This technique would be used for similar diseases, like amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA).  These stem cells developed from a singular patient would also be able to be used to produce cells affected in the above mentioned diseases.  As mentioned, it will also lead to patient specific phenotypes of each disease.  Further chemical analyses to develop safer drugs can be done through sequence information and cell-culture tests on iPSCs.  After development on a specific drug, it can be transferred to other patient diseased cells while also being safety tested.

Stem cell theory of aging: The stem cell theory of aging postulates that the aging process is the result of the inability of various types of stem cells to continue to replenish the tissues of an organism with functional differentiated cells capable of maintaining that tissue's (or organ's) original function.  Damage and error accumulation in genetic material is always a problem for systems regardless of the age.  The number of stem cells in young people is very much higher than older people and this cause a better and more efficient replacement mechanism in the young contrary to the old.  In other words, aging is not a matter of the increase of damage, but a matter of failure to replace it due to decreased number of stem cells.  Stem cells decrease in number and tend to lose the ability to differentiate into progenies or lymphoid lineages and myeloid lineages.

Progenitor cell: A progenitor cell is a biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its "target" cell.  The most important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely, whereas progenitor cells can divide only a limited number of times.  Controversy about the exact definition remains and the concept is still evolving.

Benjamin Alman: Benjamin Alman, MD, FRCSC, was the head of the division of Orthopedic surgery at the Hospital for Sick Children in Toronto, Ontario, senior scientist in developmental and stem cell biology at Sick Kids, and vice chair of the department of surgery at the University of Toronto.  He has given many speeches and lectures throughout the world, and has won many awards and prizes, including the Premier’s Research Excellence Award, the Huene Award, the OREF Research Award, and the Royal College Medal in Surgery.  .  As of June 1, 2013, he is the head of Orthopedics at Duke University Medical School in Durham, North Carolina.

Muse cell: Muse cells are identified as cells positive for SSEA-3+, a well-known marker for undifferentiated human ES cells.  They are also positive for general mesenchymal stem cell markers such as CD105, CD90 and CD29.  Therefore, Muse cells are double positive for pluripotent and mesenchymal stem cell markers.  Cell isolation by SSEA-3 cell sorting can be done using SSEA-3 antibody.  Their size is 13~15 μm in diameter.  Muse cells do not express CD34 (markers for hematopoietic stem cells, adipose stem cells, VSELs) and CD117 (hematopoietic stem cells markers), Snai1 and Slug (skin-derived precursors markers), CD271 and Sox10 (neural crest-derived stem cells markers), NG2 and CD146 (perivascular cells) or CD31 and von Willebrand factor (endothelial progenitor markers).  This indicates that Muse cells do not belong to previously investigated stem cell types.

Neural stem cell: Neural stem cells (NSCs) are self-renewing, multipotent cells that generate the neurons and glia of the nervous system of all animals during embryonic development.  Some neural stem cells persist in the adult vertebrate brain and continue to produce neurons throughout life.  Stem cells are characterized by their capacity to differentiate into multiple cell types.  They undergo symmetric or asymmetric cell division into two daughter cells.  In symmetric cell division, both daughter cells are also stem cells.  In asymmetric division, a stem cells produces one stem cell and one specialized cell.  NSCs primarily differentiate into neurons, astrocytes, and oligodendrocytes.

Retinal precursor cells: Retinal precursor cells are biological cells that differentiate into the various cell types of the retina during development.  In the vertebrate, these retinal cells differentiate into seven cell types, including retinal ganglion cells, amacrine cells, bipolar cells, horizontal cells, rod photoreceptors, cone photoreceptors, and Müller glia cells.  During embryogenesis, retinal cells originate from the anterior portion of the neural plate termed the eye field.  Eye field cells with a retinal fate express several transcription factor markers including Rx1, Pax6, and Lhx2.  The eye field gives rise to the optic vesicle and then to the optic cup.  The retina is generated from the precursor cells within the inner layer of the optic cup, as opposed to the retinal pigment epithelium that originate from the outer layer of the optic cup.  In general, the developing retina is organized so that the least-committed precursor cells are located in the periphery of the retina, while the committed cells are located in the center of the retina.  The differentiation of retinal precursor cells into the mature cell types found in the retina is coordinated in time and space by factors within the cell as well as factors in the environment of the cell.  One example of an intrinsic regulator of this process is the transcription factor Ath5.  Ath5 expression in retinal progenitor cells biases their differentiation into a retinal ganglion cell fate.  An example of an environmental factor is the morphogen sonic hedge hog (Shh).  Shh has been shown to repress the differentiation of precursor cells into retinal ganglion cells.

Stem cell: Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells.  They are found in multicellular organisms.  In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues.  In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues.  In a developing embryo, stem cells can differentiate into all the specialized cells—ectoderm, endoderm and mesoderm (see induced pluripotent stem cells)—but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.

Endothelial stem cell: Endothelial stem cells (ESCs) are one of three types of stem cells found in bone marrow.  They are multipotent, which describes the ability to give rise to many cell types, whereas a pluripotent stem cell can give rise to all types.  ESCs have the characteristic properties of a stem cell: self-renewal and differentiation.  These parent stem cells, ESCs, give rise to progenitor cells, which are intermediate stem cells that lose potency.  Progenitor stem cells are committed to differentiating along a particular cell developmental pathway.  ESCs will eventually produce endothelial cells (ECs), which create the thin-walled endothelium that lines the inner surface of blood vessels and lymphatic vessels.

Labile cell: In cellular biology, labile cells are cells that multiply constantly throughout life.  The cells are alive for only a short period of time.  Due to this,they can end up reproducing new stem cells and replace functional cells.  Especially if the cells become injured through a process called necrosis, or even if the cells go through apoptosis. The way these cells regenerate and replace themselves is quite unique.  While going through cell division, one of the two daughter cells actually becomes a new stem cell.  This occurs so then that daughter cell can end up restoring the population of the stem cells that were lost.  The other daughter cell separates itself into a functional cell in order to replace the lost, or injured cells during this process.  Labile cells are one type of the cells that are involved in the division of cells.  The other two types that are involved include stable cells and permanent cells.

Supporting paragraphs: Benjamin Alman Stem cell
Answer: mitosis