Instruct: Given a question, retrieve documents that answer the question.
Query: Where are stem cells located in the adult body?
Adult stem cells are undifferentiated cells, found throughout the body after development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Also known as somatic stem cells (from Greek Σωματικóς, meaning "of the body"), they can be found in juvenile as well as adult animals and humans, unlike embryonic stem cells.
On July 24, 2009, the first publication of a successful breakthrough in Stem cell research was released, where Chinese researchers from the Shanghai Stem Cell Institute, led by Professor Fanyi Zeng, successfully reprogrammed adult stem cells to be able to differentiate into any body cell, as in the case with standard embryonic stem cells, the cells in question known as "induced pluripotent stem cells" (IPS cells). The IPS cells were obtained by genetically reprogramming the skin cells of mice to acts like embryonic stem cells, which then were able to differentiate into all forms of body tissue. The researchers have managed to use the IPS cells to create every type of cell in a mouse, creating entire mouse pups using the technique. This is the first time the technique has been used to make an entire mouse.
The discovery of adult stem cells led scientists to develop an interest in the role of embryonic stem cells, and in separate studies in 1981 Gail Martin and Martin Evans derived pluripotent stem cells from the embryos of mice for the first time. This paved the way for Mario Capecchi, Martin Evans, and Oliver Smithies to create the first knockout mouse, ushering in a whole new era of research on human disease. In 1995 adult stem cell research with human use, patented (US PTO with effect from 1995). In fact human use published in World J Surg 1991 & 1999 (B G Matapurkar). Salhan, Sudha (August 2011). Textbook of Gynecology. JP Medical Ltd. pp. 625–. .
Bharadwaj, Aditya; Glasner, Peter E. (2009). Local Cells, Global Science: The Rise of Embryonic Stem Cell Research in India. Taylor & Francis. 
^ "Dr.B.G.Matapurkar gets US patent for surgical procedure for organ regeneration - Patents". www.pharmabiz.com.
^ "Method of organogenesis and tissue regeneration/repair using surgical techniques - US Patent 6227202 Claims". patentstorm.us.
There is widespread controversy over the use of human embryonic stem cells. This controversy primarily targets the techniques used to derive new embryonic stem cell lines, which often requires the destruction of the blastocyst. Opposition to the use of human embryonic stem cells in research is often based on philosophical, moral, or religious objections. There is other stem cell research that does not involve the destruction of a human embryo, and such research involves adult stem cells, amniotic stem cells, and induced pluripotent stem cells.
Nowadays, there are several treatments (still in experimentation) related with stem cell therapy. It is a new opportunity, not only for partners with lack of gamets, but also for homosexuals and single people who wants to have offspring. Theoretically, with this therapy, we can get artificial gamets "in vitro". There are different studies, for both women and men.Stem cell therapy is really new, and everything is still under investigation. However, it could be the future for the treatment of multiple diseases, including infertility. It will take time until these studies can be available for clinics and patients as a regularity.
In 2007 it was shown that pluripotent stem cells highly similar to embryonic stem cells can be generated by the delivery of three genes ("Oct4", "Sox2", and "Klf4") to differentiated cells. The delivery of these genes "reprograms" differentiated cells into pluripotent stem cells, allowing for the generation of pluripotent stem cells without the embryo. Because ethical concerns regarding embryonic stem cells typically are about their derivation from terminated embryos, it is believed that reprogramming to these "induced pluripotent stem cells" (iPS cells) may be less controversial. Both human and mouse cells can be reprogrammed by this methodology, generating both human pluripotent stem cells and mouse pluripotent stem cells without an embryo.
Hescheler has been working with embryonic stem cells ever since the late 1980s. Beginning with studies on cellular signal transduction, and starting with works on signalling pathways in different cells (g-protein phosphorylation, electrophysiology of channels) he focussed on embryonic stem cells and has since defined many important basic aspects of both fundamental research and clinical applications. He was the first scientist worldwide to perform electrophysiological and functional experiments on stem cells and differentiated phenotypes thereof. He achieved a first functional characterization of cardiomyocytes developed from embryonic stem cells which is an important prerequisite for their subsequent use in regenerative medicine. He thus pioneered the establishment of stem cell research for application in transplantation medicine. In 2002, he was among the first scientists in Germany to obtain permission to work with human embryonic stem cells. In his current position, as Chairman and Director to the Institute for Neurophysiology at the University of Cologne, his research areas include work on embryonic and adult stem cells, induced pluripotent stem cells, mesenchymal stem cells and germline pluripotent stem cells. Among progressing the use of stem cells for translational purposes, aiming at tapping the potential of stem cell biology towards clinical application, Hescheler actively promotes the vision of EPAA through innovative alternative testing strategies, applying stem cells towards toxicity testing. Apart from the rationale of promoting 3R principles it is his goal that coordinating a multidisciplinary research effort undertaken by various projects and consortia led by Hescheler will generate pathway- and evidence-based understanding of long-term toxic effects, thus moving toxicology from a rather descriptive science towards a more mechanistic-driven predictive one. 
Hescheler has been appointed coordinator of various European Consortia such as FunGenES, CRYSTAL, and more recently ESNATS and DETECTIVE. He is also coordinator of the BMBF consortium “iPS and adult bone marrow cells for cardiac repair”. In 2004 he founded and since chaired the German Society of Stem Cell Research (GSZ). He is an active member of the Scientific Panel of the AXLR8 Consortium and a member of steering committee of Stem Cell Network North Rhine Westphalia.
The discovery of insulin at the University of Toronto in 1921 is considered among the most significant events in the history of medicine. The stem cell was discovered at the university in 1963, forming the basis for bone marrow transplantation and all subsequent research on adult and embryonic stem cells. This was the first of many findings at Toronto relating to stem cells, including the identification of pancreatic and retinal stem cells. The cancer stem cell was first identified in 1997 by Toronto researchers, who have since found stem cell associations in leukemia, brain tumors and colorectal cancer. Medical inventions developed at Toronto include the glycaemic index, the infant cereal Pablum, the use of protective hypothermia in open heart surgery and the first artificial cardiac pacemaker. The first successful single-lung transplant was performed at Toronto in 1981, followed by the first nerve transplant in 1988, and the first double-lung transplant in 1989. Researchers identified the maturation promoting factor that regulates cell division, and discovered the T-cell receptor, which triggers responses of the immune system. The university is credited with isolating the genes that cause Fanconi anemia, cystic fibrosis and early-onset Alzheimer's disease, among numerous other diseases. Between 1914 and 1972, the university operated the Connaught Medical Research Laboratories, now part of the pharmaceutical corporation Sanofi-Aventis. Among the research conducted at the laboratory was the development of gel electrophoresis.
Bone marrow transplant can replace the transplant recipient's immune system with the donor's, and the recipient accepts the new organ without rejection. The marrow's hematopoietic stem cells—the reservoir of stem cells replenishing exhausted blood cells including white blood cells forming the immune system—must be of the individual who donated the organ or of an identical twin or a clone. There is a risk of graft-versus-host disease (GVHD), however, whereby mature lymphocytes entering with marrow recognize the new host tissues as foreign and destroy them.
In the human body at birth, there are over 270 bones, but many of these fuse together during development, leaving a total of 206 separate bones in the adult, not counting numerous small sesamoid bones. The largest bone in the body is the femur or thigh-bone, and the smallest is the stapes in the middle ear.
Cells in the body function because of DNA. DNA sits within the nucleus of a cell. Here, parts of DNA are copied and sent to the body of the cell via RNA. The RNA is then used to create proteins which form the basis for cells, their activity, and their products. Proteins dictate cell function and gene expression, a cell is able to self-regulate by the amount of proteins produced. However, not all cells have DNA – some cells such as mature red blood cells lose their nucleus as they mature.
The cells were first observed by Karl Wilhelm von Kupffer in 1876. The scientist called them "Sternzellen" (star cells or hepatic stellate cell) but thought, inaccurately, that they were an integral part of the endothelium of the liver blood vessels and that they originated from it. In 1898, after several years of research, Tadeusz Browicz identified them, correctly, as macrophages.
In the past, it has been a necessity to research embryonic stem cells and in doing so destroy them for research to progress. As a result of the research done with both embryonic and adult stem cells, new techniques may make the necessity for embryonic cell research obsolete. Because many of the restrictions placed on stem cell research have been based on moral dilemmas surrounding the use of embryonic cells, there will likely be rapid advancement in the field as the techniques that created those issues are becoming less of a necessity. Many funding and research restrictions on embryonic cell research will not impact research on IPSCs (induced pluripotent stem cells) allowing for a promising portion of the field of research to continue relatively unhindered by the ethical issues of embryonic research.
Blood accounts for 7% of the human body weight, with an average density around 1060 kg/m, very close to pure water's density of 1000 kg/m. The average adult has a blood volume of roughly , which is composed of plasma and several kinds of cells. These blood cells (which are also called corpuscles or "formed elements") consist of erythrocytes (red blood cells, RBCs), leukocytes (white blood cells), and thrombocytes (platelets). By volume, the red blood cells constitute about 45% of whole blood, the plasma about 54.3%, and white cells about 0.7%.
The corpuscles of Stannius are special endocrine organs in the kidney in fish and are responsible for maintaining calcium balance. They are found only in bony fishes. They were discovered and described by a German anatomist Hermann Friedrich Stannius in 1839. Stannius considered them as functionally similar to adrenal glands in mammals. But they have later been found to be anatomically different as they are derived from different tissues of the embryo. Structurally the corpuscles are a large number of spherical bodies separated from each other by loose connective tissues. Each body or lobule is in turn composed of several columnar cells, which contain secretory granules and are, thus, secretory in function. Each Secretory granule is spherical in shape and measures 0.5 to 1 μm in diameter. Their possible endocrine nature, i.e. producing hormone, was suspected from the complete anatomical description, and it was believed to be responsible for regulating calcium level in the blood. The hormone was identified as stanniocalcin.
The jejunum lies between the duodenum and the ileum and is considered to start at the suspensory muscle of the duodenum, a location called the duodenojejunal flexure. The division between the jejunum and ileum is not anatomically distinct due to the fact that in adult humans, the small intestine is usually 6-7m long, about two-fifths of which (2.5 m) is the jejunum.
Schmid and Seipel argue that the origin of muscle cells is a monophyletic trait that occurred concurrently with the development of the digestive and nervous systems of all animals and that this origin can be traced to a single metazoan ancestor in which muscle cells are present. They argue that molecular and morphological similarities between the muscles cells in cnidaria and ctenophora are similar enough to those of bilaterians that there would be one ancestor in metazoans from which muscle cells derive. In this case, Schmid and Seipel argue that the last common ancestor of bilateria, ctenophora, and cnidaria was a triploblast or an organism with three germ layers and that diploblasty, meaning an organism with two germ layers, evolved secondarily due to their observation of the lack of mesoderm or muscle found in most cnidarians and ctenophores. By comparing the morphology of cnidarians and ctenophores to bilaterians, Schmid and Seipel were able to conclude that there were myoblast-like structures in the tentacles and gut of some species of cnidarians and in the tentacles of ctenophores. Since this is a structure unique to muscle cells, these scientists determined based on the data collected by their peers that this is a marker for striated muscles similar to that observed in bilaterians. The authors also remark that the muscle cells found in cnidarians and ctenophores are often contests due to the origin of these muscle cells being the ectoderm rather than the mesoderm or mesendoderm. The origin of true muscles cells is argued by others to be the endoderm portion of the mesoderm and the endoderm. However, Schmid and Seipel counter this skepticism about whether or not the muscle cells found in ctenophores and cnidarians are true muscle cells by considering that cnidarians develop through a medusa stage and polyp stage. They observe that in the hydrozoan medusa stage there is a layer of cells that separate from the distal side of the ectoderm to form the striated muscle cells in a way that seems similar to that of the mesoderm and call this third separated layer of cells the ectocodon. They also argue that not all muscle cells are derived from the mesendoderm in bilaterians with key examples being that in both the eye muscles of vertebrates and the muscles of spiralians these cells derive from the ectodermal mesoderm rather than the endodermal mesoderm. Furthermore, Schmid and Seipel argue that since myogenesis does occur in cnidarians with the help of molecular regulatory elements found in the specification of muscles cells in bilaterians that there is evidence for a single origin for striated muscle.
The National Academies called for the establishment of Embryonic Stem Cell Research Oversight (ESCRO) Committees in its 2005 "Guidelines for Human Embryonic Stem Cell Research" to manage the ethical and legal concerns in human embryonic stem cell research. Because of the complexity and novelty of many of the issues involved in that research, the Guidelines committee believes that all research institutions engaged in human embryonic stem cell research should create and maintain these committees at the local level.
For a long time it was thought that microglial cells differentiate in the bone marrow from hematopoietic stem cells, the progenitors of all blood cells. However, recent studies show that microglia originate in the yolk sac during a remarkably restricted embryonal period and populate the brain mesenchyme. Additionally, they continuously renew themselves and persist throughout life without replenishment from peripheral monocytic precursors.
Monocytes can also differentiate into myeloid dendritic cells and macrophages in the peripheral systems. Like macrophages in the rest of the body, microglia use phagocytic and cytotoxic mechanisms to destroy foreign materials. Microglia and macrophages both contribute to the immune response by acting as antigen presenting cells, as well as promoting inflammation and homeostatic mechanisms within the body by secreting cytokines and other signaling molecules.
Cell theory led biologists to re-envision individual organisms as interdependent assemblages of individual cells. Scientists in the rising field of cytology, armed with increasingly powerful microscopes and new staining methods, soon found that even single cells were far more complex than the homogeneous fluid-filled chambers described by earlier microscopists. Robert Brown had described the nucleus in 1831, and by the end of the 19th century cytologists identified many of the key cell components: chromosomes, centrosomes mitochondria, chloroplasts, and other structures made visible through staining. Between 1874 and 1884 Walther Flemming described the discrete stages of mitosis, showing that they were not artifacts of staining but occurred in living cells, and moreover, that chromosomes doubled in number just before the cell divided and a daughter cell was produced. Much of the research on cell reproduction came together in August Weismann's theory of heredity: he identified the nucleus (in particular chromosomes) as the hereditary material, proposed the distinction between somatic cells and germ cells (arguing that chromosome number must be halved for germ cells, a precursor to the concept of meiosis), and adopted Hugo de Vries's theory of pangenes. Weismannism was extremely influential, especially in the new field of experimental embryology.
The adrenal medulla is at the centre of each adrenal gland, and is surrounded by the adrenal cortex. The chromaffin cells of the medulla are the body's main source of the catecholamines adrenaline and noradrenaline, released by the medulla. Approximately 20% noradrenaline (norepinephrine) and 80% adrenaline (epinephrine) are secreted here.
Pluripotent stem cells, i.e. cells that can give rise to any fetal or adult cell type, can be found in a number of tissues, including umbilical cord blood. Using genetic reprogramming, pluripotent stem cells equivalent to embryonic stem cells have been derived from human adult skin tissue. Other adult stem cells are multipotent, meaning they are restricted in the types of cell they can become, and are generally referred to by their tissue origin (such as mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, etc.). A great deal of adult stem cell research has focused on investigating their capacity to divide or self-renew indefinitely, and their potential for differentiation. In mice, pluripotent stem cells can be directly generated from adult fibroblast cultures.
Stem-cell niche refers to a microenvironment, within the specific anatomic location where stem cells are found, which interacts with stem cells to regulate cell fate. The word 'niche' can be in reference to the "in vivo" or "in vitro" stem-cell microenvironment. During embryonic development, various niche factors act on embryonic stem cells to alter gene expression, and induce their proliferation or differentiation for the development of the fetus. Within the human body, stem-cell niches maintain adult stem cells in a quiescent state, but after tissue injury, the surrounding micro-environment actively signals to stem cells to promote either self-renewal or differentiation to form new tissues. Several factors are important to regulate stem-cell characteristics within the niche: cell–cell interactions between stem cells, as well as interactions between stem cells and neighbouring differentiated cells, interactions between stem cells and adhesion molecules, extracellular matrix components, the oxygen tension, growth factors, cytokines, and the physicochemical nature of the environment including the pH, ionic strength (e.g. Ca concentration) and metabolites, like ATP, are also important. The stem cells and niche may induce each other during development and reciprocally signal to maintain each other during adulthood.
The primitive stem cells located in the organs of fetuses are referred to as fetal stem cells.
There are two types of fetal stem cells:Adult stem cells, also called somatic (from Greek σωματικóς, "of the body") stem cells, are stem cells which maintain and repair the tissue in which they are found. They can be found in children, as well as adults.
Stem cells are cells found in all multi-cellular organisms. They were isolated in mice in 1981, and in humans in 1998. In humans there are many types of stem cells, each with varying levels of potency. Potency is a measure of a cell's differentiation potential, or the number of other cell types that can be made from that stem cell. Embryonic stem cells are pluripotent stem cells derived from the inner cell mass of the blastocyst. These stem cells can differentiate into all other cells in the human body and are the subject of much scientific research. However, since they must be derived from early human embryos their production and use in research has been a hotly debated topic as the emt introduce new cells into adult bodies for possible treatment of cancer, diabetes, neurological disorders and other medical conditions. Stem cells have been used to repair tissue damaged by disease or age. Cloning also might be done with stem cells. Pluripotent stem cells can also be derived from Somatic cell nuclear transfer which is a laboratory technique where a clone embryo is created from a donor nucleus. Somatic cell nuclear transfer is also tightly regulated amongst various countries.