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It is the result of increased cell mitosis or division (also referred to as cell proliferation). The two types of physiologic hyperplasia are compensatory and hormonal. Compensatory hyperplasia permits tissue and organ regeneration. It is common in epithelial cells of the epidermis and intestine, liver hepatocytes, bone marrow cells, and ...
For studies of regeneration urodele amphibians such as the axolotl Ambystoma mexicanum are used, [53] and also planarian worms such as Schmidtea mediterranea. [10] Organoids have also been demonstrated as an efficient model for development. [54] Plant development has focused on the thale cress Arabidopsis thaliana as a model organism. [55]
Epimorphosis is defined as the regeneration of a specific part of an organism in a way that involves extensive cell proliferation of somatic stem cells, [1] dedifferentiation, and reformation, [2] as well as blastema formation. [3]
Development and regeneration involves the coordination and organization of populations cells into a blastema, which is "a mound of stem cells from which regeneration begins". [25] Dedifferentiation of cells means that they lose their tissue-specific characteristics as tissues remodel during the regeneration process.
Immune system contribution to regeneration of tissues generally involves specific cellular components, transcription of a wide variety of genes, morphogenesis, epithelia renewal and proliferation of damaged cell types (progenitor or tissue-resident stem cells). However, current knowledge reveals more and more studies about immune system ...
The spike in food prices prevented many people from escaping poverty, because the poor spend a larger proportion of their income on food and farmers are net consumers of food. [109] High food prices cause consumers to have less purchasing power and to substitute more-nutritious foods with low-cost alternatives.
The activation of T H 1 and M1 macrophage is a positive feedback loop, with IFN-γ from T H 1 cells upregulating CD40 expression on macrophages; the interaction between CD40 on the macrophages and CD40L on T cells activate macrophages to secrete IL-12; and IL-12 promotes more IFN-γ secretion from T H 1 cells.
In central tolerance, dendritic cells are present within the thymus, or the location of T cell development and maturation. Thymic dendritic cells can intake dead medullary thymic epithelial cells, and cross present "self" peptides on MHC class I as a negative selection check on cytotoxic T cells that have a high affinity for self peptides. [6]