Lifespan number and proliferative capacity of mammary epithelial stem cells

Primary mammary epithelial stem cells persist throughout the reproductive lifespan of the animal, allowing the gland to develop and differentiate with each pregnancy. However, serial transplantation studies indicated that mouse mammary epithelial stem cells are not immortal. Mammary epithelium can be transferred serially to host animals up to seven times before it becomes incapable of repopulating the mammary fat pad, although more than 75 of epithelial outgrowths lose their repopulating...

Thymus organogenesis

Third Pharyngeal Pouch and Arch Epithelium and Neural Crest-Derived Mesenchyme Steps of thymus organogenesis and some of the known genes involved in this process are outlined in Fig. 1. The thymus originates from the third pharyngeal pouch and the third and fourth pharyngeal arches. On embryonic d 10, at this location, endodermal epithelium is situated next to neural crest-derived mesenchymal cells. Several studies have shown that mesenchyme plays a critical role for thymus organogenesis...

Defining components of the thymic epithelial environment using monoclonal antibodies

Several groups generated comprehensive panels of monoclonal antibodies (mAbs) recognizing distinct elements of thymic epithelium (see refs. 18 and 55-57). According to their reactivity, these antibodies have been grouped into markers recognizing pan-epithelium, subcapsular and septum structures, fibroblasts, cortical epithelium, medullary epithelium, Hassall's corpuscles (enigmatic structures in the medullary zones), endothelium, and miscellaneous structures. Most of these reagents are reactive...

Muscle to blood blood to muscle

Another area of active study has been the hematopoietic potential of muscle-derived stem cells and the ability of hematopoietic stem cells to produce muscle. Jackson et al. (28) dissected muscle tissue from mice and cultured these cells for 5 d in chick embryo extract. These conditions are conducive to the growth of muscle satellite cells, which act as stem cells within the muscle. Lethally irradiated mice were transplanted with 18,000 muscle cells mixed with 200,000 whole bone marrow cells to...

Mitsuko Kosaka Guangwei Sun Masatoshi Haruta and Masayo Takahashi

The discovery of adult stem cells indicated a previously unrecognized degree of plasticity in stem cell function (1-3). Recent extensive studies have suggested that mammalian stem cells residing in one tissue may have the capacity to produce differentiated cell types for other tissues and organs (4-6). However, more recent reports raised questions about some of the earlier results, proposing that transdifferentiation consequent to cell fusion could underlie many observations otherwise...

Differentiation potential of dpscs in vitro and in vivo

Dpsc Stem Cells

Regenerating a Dentin-Pulp Complex In Vivo Mineralization within the papal chamber is a frequent event that usually manifests as small calcified pulp stones because of caries, aging, trauma, and systemic conditions (46). Previous studies have established animal cell cultures from dental pulp tissue using a variety of culture methods and noted the ability of such cultures to form mineralized nodules in vitro (43,47-50). In analogy, human-derived dental pulp can also be cultivated in vitro...

Strategies for gene transfer into muscle

Mdsc Transplantation

Various approaches can be used to achieve gene transfer to the muscu-loskeletal system, including cell therapy myoblast transplantation , gene therapy based on viral and nonviral vectors , and a combination of both techniques. A description of the various approaches used to deliver growth factors into injured skeletal muscle follows. It is hoped that, through cell and gene therapy, substances such as growth factors can be delivered to promote efficient healing and complete functional recovery...

Monica L Vetter and Edward M Levine

Eye Cell Populations

Degenerative diseases of the retina result in the loss of specific populations of retinal neurons. For example, retinitis pigmentosa is characterized by progressive loss of rod photoreceptors, macular degeneration is a common disease of the elderly in which rod and cone photoreceptors degenerate, and glaucoma is marked by a loss of retinal ganglion cells. Thus, there is considerable interest in identifying retinal stem cells with the capacity to repopulate the retina in response to disease or...

Characterization of human dental pulp stem cells

Proliferation Capacity of DPSCs In Vitro We first identified putative human DPSCs by their ability to generate clonogenic cell colonies in vitro, a common feature displayed by various stem cell populations previously isolated from other tissues. To determine the colony-forming efficiency of DPSCs from whole pulp tissue, single-cell suspensions were prepared by collagenase-dispase treatment of pulp fragments, followed by filtration through a fine mesh to remove cell aggregates prior to...

Stem cells in the bone marrow compartment

Less than 0.1 of all nucleated cells in the bone marrow are stem cells. Among these, hematopoietic stem cells HSCs provide a source of circulating erythrocytes, leukocytes, and platelets Fig. 1 . The HSC pool can be subdivided into long-term reconstituting HSCs, which have the greatest self-renewal capacity, and short-term HSCs, which generate hematopoietic lineages only for several weeks 11 . Mesenchymal stromal stem cells From Adult Stem Cells Edited by K. Turksen Humana Press Inc., Totowa,...

Embryonic endothelial progenitor cells

Synthesis Cholesterol Vivo

Embryonic stem cell research has opened a novel door for vascular biology, as for any medical field, to elucidate the history of vascular development. Embryonic endothelial progenitor cells, so-called angioblasts, for blood vessel development arise from migrating mesodermal cells. EPCs have the capacity to proliferate, migrate, and differentiate into endothelial lineage cells, but have not yet acquired characteristic mature endothelial markers. Available evidence suggests that hematopoietic...

Stem cells of the adult liver

Polygonal Cells Liver

Unlike rapidly renewing epithelial tissues such as the intestinal mucosa or epidermis , in which an active stem cell lineage system continually initiates replacement of differentiated cells that are shed 4,5 , the liver is normally a quiescent organ with minimal or slow rates of cell turnover in the adult 51 . Nonetheless, the liver possesses an extraordinary capacity for the regeneration of tissue mass following loss of normal hepatocyte numbers because of partial tissue loss surgical...

Endothelial progenitor cells for therapeutic vasculogenesis

Endothelial Progenitor Cell Transplantation The regenerative potential of stem cells has been under intense investigation. In vitro, stem and progenitor cells possess the capability of self-renewal and differentiation into organ-specific cell types. In vivo, transplantation of these cells may reconstitute organ systems, as shown in animal models of diseases 15,26,50-53 . In contrast, differentiated cells do not exhibit such characteristics. Human EPCs have been isolated from the peripheral...

Stem cell hierarchies

Hierarchies of division-competent cells have been demonstrated in other adult tissues, such as blood and the small intestine 44,45 . These hierarchies comprise a primary tissue-specific stem cell that can produce all the cell types of the tissue, including new stem cells. Downstream of the primary stem cell are more restricted progenitors that give rise only to a subset of cell types, and then there are lineage-committed progenitors that produce only one particular cell type. The number of...

Structure and histology of normal and malignant human breast

The human breast, in common with the mammary glands of other species, contains both epithelial and mesenchymal components. The adult human breast contains a number of treelike glandular structures derived by dichotomous branching of each of several ducts arising from the nipple. The major functional units of these glands are the lobular structures, situated at the end of the terminal ductules, which comprise several smaller blind-ended ductules often referred to as terminal ductal...

References

Cross-bridge action present views, prospects, and unknowns. J Biomech 33, 1189-1195. 2. Huxley, A. F. 2000 . Mechanics and models of the myosin motor. Philos Trans R Soc Lond B Biol Sci 355, 433-440. 3. Mauro, A. 1961 . Satellite cell of skeletal muscle fibers. J Biophys Biochem Cytol 9, 493-495. 4. Bischoff, R. 1990 . Interaction between satellite cells and skeletal muscle fibers. Development 109, 943-952. 5. Bischoff, R. and Heintz, C. 1994 . Enhancement of skeletal...