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Pyridinoline
Pyridinoline, also known as Hydroxylysylpyridinoline, is a fluorescent cross-linking compound of collagen fibers. Crosslinks in collagen and elastin are derived from lysyl and hydroxylysyl residues, a process catalyzed by lysyl oxidase. Fujimoto and colleagues first described the isolation and characterization of a fluorescent material in bovine Achilles tendon collagen and termed it pyridinoline. It is reported to be present in collagen of bone and cartilage, but is absent in collagen of skin. It is not present in newly synthesized collagen and is formed from aldimine cross-links during maturation of collagen fibers. Pyridinoline and deoxypyridinoline were found to be released into the blood during bone degradation and rapidly excreted in the urine. In a preliminary study, both these compounds were proposed as a marker for metastatic bone tumor A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescent
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacuu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole-body protein content. Collagen consists of amino acids bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in connective tissue such as cartilage, bones, tendons, ligaments, and skin. Depending upon the degree of mineralization, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in corneas, blood vessels, the gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes one to two percent of muscle tissue and accounts for 6% of the weight of the skeletal muscle tissue. The fibroblast is the most common cell that crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain lysyl ((CH2)4NH2), classifying it as a basic, charged (at physiological pH), aliphatic amino acid. It is encoded by the codons AAA and AAG. Like almost all other amino acids, the α-carbon is chiral and lysine may refer to either enantiomer or a racemic mixture of both. For the purpose of this article, lysine will refer to the biologically active enantiomer L-lysine, where the α-carbon is in the ''S'' configuration. The human body cannot synthesize lysine. It is essential in humans and must therefore be obtained from the diet. In organisms that synthesise lysine, two main biosynthetic pathways exist, the diaminopimelate and α-aminoadipate pathways, which employ distinct e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxylysine
Hydroxylysine (Hyl) is an amino acid with the molecular formula C6H14N2O3. It was first discovered in 1921 by Donald Van Slyke as the 5-hydroxylysine form. It arises from a post-translational hydroxy modification of lysine. It is most widely known as a component of collagen. It is biosynthesized from lysine via oxidation by lysyl hydroxylase Lysyl hydroxylases (or procollagen-lysine 5-dioxygenases) are alpha-ketoglutarate-dependent hydroxylases enzymes that catalyze the hydroxylation of lysine to hydroxylysine. Lysyl hydroxylases require iron and vitamin C as cofactors for their ... enzymes. The most common form is the (5''R'') stereoisomer found in collagen. However, the enzyme JMJD6 has recently been shown to be a lysyl hydroxylase which modifies an RNA splicing factor producing the (5''S'') stereoisomer. Additionally, in ''E. coli'', there has been at least one lysine ''N''-hydroxylase enzyme identified, named IucD. References External links * {{MeshName, Hydroxyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysyl Oxidase
Lysyl oxidase (LOX), also known as protein-lysine 6-oxidase, is an enzyme that, in humans, is encoded by the ''LOX'' gene. It catalyzes the conversion of lysine molecules into highly reactive aldehydes that form cross-links in extracellular matrix proteins. Its inhibition can cause osteolathyrism, but, at the same time, its upregulation by tumor cells may promote metastasis of the existing tumor, causing it to become malignant and cancerous. Structure In the yeast strain ''Pichia pastoris'', lysyl oxidase constitutes a homodimeric structure. Each monomer consists of an active site that includes a Cu(II) atom coordinated with three histidine residues as well as 2,4,5-trihydroxyphenalanine quinone (TPQ), a crucial cofactor. In humans, the LOX gene is located on chromosome 5 q23.3-31.2. The DNA sequence encodes a polypeptide of 417 amino acids, the first 21 residues of which constitute a signal peptide, with a weight of approximately 32 kDa. The carboxyterminus contains the act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldimine
In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions. Structure For ketimines and aldimines, respectively, the five core atoms (C2C=NX and C(H)C=NX, X = H or C) are coplanar. Planarity results from the sp2-hybridization of the mutually double-bonded carbon and the nitrogen atoms. The C=N distance is 1.29-1.31 Å for nonconjugated imines and 1.35 Å for conjugated imines. By contrast, C-N distances in amines and nitriles are 1.47 and 1.16 Å, respectively. Rotation about the C=N bond is slow. Using NMR spectroscopy, both E- and Z-isomers of aldimines have been detected. Owing to steric effects, the E isomer is favored. Nomenclature and classification The term "imine" was coined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxypyridinoline
Deoxypyridinoline, also called D-Pyrilinks, Pyrilinks-D, or deoxyPYD, is one of two pyridinium cross-links that provide structural stiffness to type I collagen found in bones. It is excreted unmetabolized in urine and is a specific marker of bone resorption and osteoclastic activity. It is measured in urine tests and is used along with other bone markers such as alkaline phosphatase, osteocalcin, and N-terminal telopeptide to diagnose bone diseases such as postmenopausal osteoporosis, bone metastasis, and Paget's disease, furthermore, it has been useful in monitoring treatments that contain bone-active agents such as estrogens and bisphosphonates Bisphosphonates are a class of drugs that prevent the loss of bone density, used to treat osteoporosis and similar diseases. They are the most commonly prescribed drugs used to treat osteoporosis. They are called bisphosphonates because they h .... Certain studies have attempted to generate a standardization of Deoxypyridinolin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metastatic
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, are metastases (mets). It is generally distinguished from cancer invasion, which is the direct extension and penetration by cancer cells into neighboring tissues. Cancer occurs after cells are genetically altered to proliferate rapidly and indefinitely. This uncontrolled proliferation by mitosis produces a primary heterogeneic tumour. The cells which constitute the tumor eventually undergo metaplasia, followed by dysplasia then anaplasia, resulting in a malignant phenotype. This malignancy allows for invasion into the circulation, followed by invasion to a second site for tumorigenesis. Some cancer cells known as circulating tumor cells acquire the ability to penetrate the walls of lymphatic or blood vessels, after which they are able ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Tumor
A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thyroid, kidney and prostate. There may be a lump, pain, or neurological signs from pressure. A bone tumor might present with a pathologic fracture. Other symptoms may include fatigue, fever, weight loss, anemia and nausea. Sometimes there are no symptoms and the tumour is found when investigating another problem. Diagnosis is generally by X-ray and other radiological tests such as CT scan, MRI, PET scan and bone scintigraphy. Blood tests might include a complete blood count, inflammatory markers, serum electrophoresis, PSA, kidney function and liver function. Urine may be tested for Bence Jones protein. For confirmation of diagnosis, a biopsy for histological evaluation might be required. The most common bone tumor is a non-ossifying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate Cancer
Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that surrounds the urethra just below the bladder. It is located in the hypogastric region of the abdomen. To give an idea of where it is located, the bladder is superior to the prostate gland as shown in the image The rectum is posterior in perspective to the prostate gland and the ischial tuberosity of the pelvic bone is inferior. Only those who have male reproductive organs are able to get prostate cancer. Most prostate cancers are slow growing. Cancerous cells may spread to other areas of the body, particularly the bones and lymph nodes. It may initially cause no symptoms. In later stages, symptoms include pain or difficulty urinating, blood in the urine, or pain in the pelvis or back. Benign prostatic hyperplasia may produce similar symptoms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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