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Elastin
Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective tissue of the body to resume its shape after stretching or contracting. Elastin helps skin return to its original position whence poked or pinched. Elastin is also in important load-bearing tissue of vertebrates and used in places where storage of mechanical energy is required. Function The ''ELN'' gene encodes a protein that is one of the two components of elastic fibers. The encoded protein is rich in hydrophobic amino acids such as glycine and proline, which form mobile hydrophobic regions bounded by crosslinks between lysine residues. Multiple transcript variants encoding different isoforms have been found for this gene. Elastin's soluble precursor is tropoelastin. Mechanism of elastic recoil The characterization of disorder is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Fibers
Elastic fibers (or yellow fibers) are an essential component of the extracellular matrix composed of bundles of proteins (elastin) which are produced by a number of different cell types including fibroblasts, endothelial, smooth muscle, and airway epithelial cells. These fibers are able to stretch many times their length, and snap back to their original length when relaxed without loss of energy. Elastic fibers include elastin, elaunin and oxytalan. Elastic fibers are formed via elastogenesis, a highly complex process involving several key proteins including fibulin-4, fibulin-5, latent transforming growth factor β binding protein 4, and microfibril associated protein 4. In this process tropoelastin, the soluble monomeric precursor to elastic fibers is produced by elastogenic cells and chaperoned to the cell surface. Following excretion from the cell, tropoelastin self associates into ~200 nm particles by coacervation, an entropically driven process involving interacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM. The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest. Each type of connective tissue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williams Syndrome
Williams syndrome (WS), also Williams–Beuren syndrome (WBS), is a genetic disorder that affects many parts of the body. Facial features frequently include a broad forehead, underdeveloped chin, short nose, and full cheeks. Mild to moderate intellectual disability is observed, particularly challenges with visual spatial tasks such as drawing. Verbal skills are relatively unaffected. Many people have an outgoing personality, a happy disposition, an openness to engaging with other people, increased empathy and decreased aggression. Medical issues with teeth, heart problems (especially supravalvular aortic stenosis), and periods of hypercalcemia, high blood calcium are common. Williams syndrome is caused by a genetic abnormality, specifically a Deletion (genetics), deletion of about 27 genes from the long arm of one of the two chromosome 7s. Typically, this occurs as a random event during the formation of the egg or sperm from which a person develops. In a small number of cases, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutis Laxa
Cutis laxa or pachydermatocele is a group of rare connective tissue disorders in which the skin becomes inelastic and hangs loosely in folds. Signs and symptoms It is characterised by skin that is loose, hanging, wrinkled, and lacking in elasticity. The loose skin can be either generalised or localised. Biopsies have shown reduction and degeneration of dermal elastic fibres in the affected areas of skin. The loose skin is often most noticeable on the face, resulting in a prematurely aged appearance. The affected areas of skin may be thickened and dark. In addition, the joints may be loose ( hypermobile) because of lax ligaments and tendons. When cutis laxa is severe, it can also affect the internal organs. The lungs, heart (supravalvular pulmonary stenosis), intestines, or arteries may be affected with a variety of severe impairments. In some cases, hernias and outpouching of the bladder can be observed. Patients can also present with whites of the eyes that are blue. Causes In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha 1-antitrypsin
Alpha-1 antitrypsin or α1-antitrypsin (A1AT, α1AT, A1A, or AAT) is a protein belonging to the serpin superfamily. It is encoded in humans by the ''SERPINA1'' gene. A protease inhibitor, it is also known as alpha1–proteinase inhibitor (A1PI) or alpha1-antiproteinase (A1AP) because it inhibits various proteases (not just trypsin). As a type of enzyme inhibitor, it protects tissues from enzymes of inflammatory cells, especially neutrophil elastase. When the blood contains inadequate or defective A1AT (as in alpha-1 antitrypsin deficiency), neutrophil elastase can excessively break down elastin, leading to the loss of elasticity in the lungs. This results in respiratory issues, such as chronic obstructive pulmonary disease, in adults. Normally, A1AT is produced in the liver and enters the systemic circulation. However, defective A1AT may accumulate in the liver, potentially causing cirrhosis in both adults and children. A1AT not only binds to neutrophil elastase from in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connective Tissue
Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells. Blood and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leukocytes. The term "connective tissue" (in German, ) was introduced in 1830 by Johannes Peter Müller. The tissue was already recognized as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinic Elastosis
Actinic elastosis, also known as solar elastosis, is an accumulation of abnormal elastin (elastic tissue) in the dermis of the skin, or in the conjunctiva of the eye, which occurs as a result of the cumulative effects of prolonged and excessive sun exposure, a process known as photoaging. Signs and symptoms Actinic elastosis usually appears as thickened, dry, wrinkled skin. Several clinical variants have been recorded. One of the most readily identifiable is the thickened, deeply fissured skin seen on the back of the chronically sun-exposed neck, known as cutis rhomboidalis nuchae. These features are a part of the constellation of changes that are seen in photoaged skin. Causes The origin of the elastotic material in the dermis remains a subject of debate. Theories on the formation of the elastotic material include actinic stimulation of fibroblasts, promoting synthesis of this material, or that the material is a degradation product of collagen, elastin, or both. Diagnosis In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoaging
Photoaging or photoageing (also known as "dermatoheliosis") is a term used for the characteristic changes to skin induced by chronic Ultraviolet, UVA and UVB exposure. Effects of UV light Molecular and genetic changes UVB rays are a primary mutagen that can only penetrate through the epidermis (skin), epidermal (outermost) layer of the skin and can cause DNA mutations. These mutations arise due to chemical changes within skin cells. These mutations may be clinically related to specific signs of photoaging such as wrinkling. Melanocytes and basal cells are embedded in the epidermal layer. Upon exposure to UVB rays, melanocytes will produce more melanin, a pigment that gives skin its color. UVB can cause the formation of freckles and dark spots, both of which are symptoms of photoaging; these are most common in people with fair or light skin. With frequent long-term exposure to UVB rays, signs of photoaging might appear and precancerous lesions or skin cancer may develop. UVA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinic Elastosis
Actinic elastosis, also known as solar elastosis, is an accumulation of abnormal elastin (elastic tissue) in the dermis of the skin, or in the conjunctiva of the eye, which occurs as a result of the cumulative effects of prolonged and excessive sun exposure, a process known as photoaging. Signs and symptoms Actinic elastosis usually appears as thickened, dry, wrinkled skin. Several clinical variants have been recorded. One of the most readily identifiable is the thickened, deeply fissured skin seen on the back of the chronically sun-exposed neck, known as cutis rhomboidalis nuchae. These features are a part of the constellation of changes that are seen in photoaged skin. Causes The origin of the elastotic material in the dermis remains a subject of debate. Theories on the formation of the elastotic material include actinic stimulation of fibroblasts, promoting synthesis of this material, or that the material is a degradation product of collagen, elastin, or both. Diagnosis In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atherosclerosis
Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by elevated blood levels of cholesterol. These lesions may lead to narrowing of the arterial walls due to buildup of atheromatous plaques. At the onset, there are usually no symptoms, but if they develop, symptoms generally begin around middle age. In severe cases, it can result in coronary artery disease, stroke, peripheral artery disease, or kidney disorders, depending on which body part(s) the affected arteries are located in the body. The exact cause of atherosclerosis is unknown and is proposed to be multifactorial. Risk factors include dyslipidemia, abnormal cholesterol levels, elevated levels of inflammatory biomarkers, high blood pressure, diabetes, smoking (both active and passive smoking), obesity, genetic factors, family history, lifes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Papillary Dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis.James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology'' (10th ed.). Saunders. Pages 1, 11–12. . The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix.Marks, James G; Miller, Jeffery (2006). ''Lookingbill and Marks' Principles of Dermatology'' (4th ed.). Elsevier Inc. Page 8–9. . It also contains mechanoreceptors that provide the sense of touch and thermoreceptors that provide the sense of heat. In addition, hair follicles, swe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
