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Bone Cells
An osteocyte, an oblate-shaped type of bone cell with dendritic processes, is the most commonly found cell in mature bone. It can live as long as the organism itself. The adult human body has about 42 billion of them. Osteocytes do not divide and have an average half life of 25 years. They are derived from osteoprogenitor cells, some of which differentiate into active osteoblasts (which may further differentiate to osteocytes). Osteoblasts/osteocytes develop in mesenchyme. In mature bones, osteocytes and their processes reside inside spaces called lacunae (Latin for a ''pit'') and canaliculi, respectively. Osteocytes are simply osteoblasts trapped in the matrix that they secrete. They are networked to each other via long cytoplasmic extensions that occupy tiny canals called canaliculi, which are used for exchange of nutrients and waste through gap junctions. Although osteocytes have reduced synthetic activity and (like osteoblasts) are not capable of mitotic division, they are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialised connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralisation of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteocyte
An osteocyte, an oblate-shaped type of bone cell with dendritic processes, is the most commonly found cell in mature bone. It can live as long as the organism itself. The adult human body has about 42 billion of them. Osteocytes do not divide and have an average half life of 25 years. They are derived from osteoprogenitor cells, some of which differentiate into active osteoblasts (which may further differentiate to osteocytes). Osteoblasts/osteocytes develop in mesenchyme. In mature bones, osteocytes and their processes reside inside spaces called lacunae (Latin for a ''pit'') and canaliculi, respectively. Osteocytes are simply osteoblasts trapped in the matrix that they secrete. They are networked to each other via long cytoplasmic extensions that occupy tiny canals called canaliculi, which are used for exchange of nutrients and waste through gap junctions. Although osteocytes have reduced synthetic activity and (like osteoblasts) are not capable of mitotic division, they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason for a broken bone among the Old age, elderly. Bones that commonly break include the vertebrae in the Vertebral column, spine, the bones of the forearm, the wrist, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, some people may have chronic pain and a decreased ability to carry out normal activities. Osteoporosis may be due to lower-than-normal peak bone mass, maximum bone mass and greater-than-normal bone loss. Bone loss increases after menopause in women due to lower levels of estrogen, and after andropause in older men due to lower levels of testosterone. Osteoporosis may also occur due to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biology), morphology) and death. These changes include Bleb (cell biology), blebbing, Plasmolysis, cell shrinkage, Karyorrhexis, nuclear fragmentation, Pyknosis, chromatin condensation, Apoptotic DNA fragmentation, DNA fragmentation, and mRNA decay. The average adult human loses 50 to 70 1,000,000,000, billion cells each day due to apoptosis. For the average human child between 8 and 14 years old, each day the approximate loss is 20 to 30 billion cells. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Senescence
Senescence () or biological aging is the gradual deterioration of Function (biology), functional characteristics in living organisms. Whole organism senescence involves an increase in mortality rate, death rates or a decrease in fecundity with increasing age, at least in the later part of an organism's biological life cycle, life cycle. However, the resulting effects of senescence can be delayed. The 1934 discovery that calorie restriction can Life extension, extend lifespans by 50% in rats, the existence of species having negligible senescence, and the existence of potentially immortal organisms such as members of the genus ''Hydra (genus), Hydra'' have motivated research into Life extension, delaying senescence and thus age-related diseases. Rare human mutations can cause accelerated aging diseases. Environmental Gerontogens, factors may affect aging – for example, overexposure to ultraviolet radiation accelerates skin aging. Different parts of the body may age at different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD34
CD34 is a transmembrane phosphoglycoprotein protein encoded by the CD34 gene in humans, mice, rats and other species. CD34 derives its name from the cluster of differentiation protocol that identifies cell surface antigens. CD34 was first described on hematopoietic stem cells independently by Civin et al. and Tindle et al. as a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of hematopoietic stem cells to bone marrow extracellular matrix or directly to stromal cells. Clinically, it is associated with the selection and enrichment of hematopoietic stem cells for bone marrow transplants. Due to these historical and clinical associations, CD34 expression is almost ubiquitously related to hematopoietic cells; however, it is actually found on many other cell types as well. Function The CD34 protein is a member of a family of single-pass transmembrane sialomucin proteins that show expression on early haematopoietic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerostin
Sclerostin is a protein that in humans is encoded by the ''SOST'' gene. It is a secreted glycoprotein with a C-terminal cysteine knot-like (CTCK) domain and sequence similarity to the DAN (differential screening-selected gene aberrative in neuroblastoma) family of bone morphogenetic protein (BMP) antagonists. Sclerostin is produced primarily by the osteocyte but is also expressed in other tissues, and has anti-anabolic effects on bone formation. Structure The sclerostin protein, with a length of 213 residues, has a secondary structure that has been determined by protein NMR to be 28% beta sheet (6 strands; 32 residues). Function Sclerostin, the product of the SOST gene, located on chromosome 17q12–q21 in humans, was originally believed to be a non-classical bone morphogenetic protein (BMP) antagonist. More recently, sclerostin has been identified as binding to LRP5/ 6 receptors and inhibiting the Wnt signaling pathway. The inhibition of the Wnt pathway leads to decrea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-linked Hypophosphatemia
Sex linkage describes the sex-specific patterns of inheritance and expression when a gene is present on a sex chromosome (allosome) rather than a non-sex chromosome (autosome). Genes situated on the X-chromosome are thus termed X-linked, and are transmitted by both males and females, while genes situated on the Y-chromosome are termed Y-linked, and are transmitted by males only. As human females possess two X-chromosomes and human males possess one X-chromosome and one Y-chromosome, the phenotype of a sex-linked trait can differ between males and females due to the differential number of alleles (polymorphisms) possessed for a given gene. In humans, sex-linked patterns of inheritance are termed X-linked recessive, X-linked dominant and Y-linked. The inheritance and presentation of all three differ depending on the sex of both the parent and the child. This makes sex-linked patterns of inheritance characteristically different from autosomal dominance and recessiveness. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynda Bonewald
Lynda Bonewald is a professor of anatomy, cell biology, physiology, and orthopaedic surgery and the founding director of the Indiana Center for Musculoskeletal Health (ICMH) at the Indiana University School of Medicine. She studies bone and the musculoskeletal system. She has served as president of the American Society for Bone and Mineral Research (ASBMR, 2012-2013) and the Association of Biomolecular Resource Facilities (1999-2000). Early life and education Bonewald graduated from the University of Texas at Austin and earned a Ph.D. in Immunology/Microbiology from the Medical University of South Carolina in 1984. Career Bonewald was a post-doctoral fellow at the Ralph H. Johnson Veterans Affairs Medical Center in Charleston, South Carolina where she worked with Makio Ogawa on growth factors for hematopoietic stem cells. Bonewald joined the University of Texas Health Science Center at San Antonio in 1986 as an assistant professor, working with Gregory Robert Mundy. In 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast Growth Factor 23
Fibroblast growth factor 23 (FGF-23) is a protein and member of the fibroblast growth factor (FGF) family which participates in the regulation of phosphate in plasma and vitamin D metabolism. In humans it is encoded by the gene. FGF-23 decreases reabsorption of phosphate in the kidney. Mutations in ''FGF23'' can lead to its increased activity, resulting in autosomal dominant hypophosphatemic rickets. Description Fibroblast growth factor 23 (FGF23) is a protein which in humans is encoded by the gene. FGF23 is a member of the fibroblast growth factor (FGF) family which participates in phosphate and vitamin D metabolism and regulation. Function FGF23´s main function is to regulate the phosphate concentration in plasma. It does this by decreasing reabsorption of phosphate in the kidney, which means phosphate is excreted in urine. FGF23 is secreted by osteocytes in response to increased calcitriol and phosphate. FGF23 acts on the kidneys by decreasing the expression of NPT2, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MEPE
''Mepe'' (Old Georgian: ႫႴ; ka, მეფე ; ) is a royal title used to designate the Georgian monarch, whether it is referring to a king or a queen regnant. The title was originally a male ruling title. Etymology The word is derived from Georgian word მეუფე (''meupe'') which literally means sovereign and lord. Some Georgian dialects has the term as ნეფე (''nepe''), all derived from common Proto-Kartvelian მფ/მეფე/მაფა (''mp/mepe/mapa''). Even though ''mepe'' has a female equivalent, დედოფალი (''dedopali;'' ) it is only applied to the king's consort and does not have a meaning of a ruling monarch. History The term ''mepe'' was utilized since pre-Christian beginnings with Azo, but the role would get more structured during the reign of Pharnavaz I in the 3rd century BC. His successors, the Pharnavazid ''mepes'' would be titled as ''goliath'' who would possess 𐬓𐬀𐬭𐬆𐬥𐬀𐬵 ('' pharnah''; ), the divinely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
