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Liver Spot
Liver spots (also known as age spot, solar lentigo, "lentigo senilis", "old age spot", "senile freckle") are wikt:blemish, blemishes on the skin associated with aging and exposure to ultraviolet, ultraviolet radiation from the sun. They range in color from light brown to red or black and are located in areas most often exposed to the sun, particularly the hands, face, shoulders, arms and forehead, and the scalp if bald. The spots derive their name from the fact that they were once incorrectly believed to be caused by liver problems, but they are physiologically unrelated to the liver, save for a similar color. From the age of 40, the skin is less able to regenerate from sun exposure, and liver spots are very common in this age group, particularly in those who spend time in the sun. In the overwhelming majority of cases, liver spots pose no threat and require no treatment, though they occasionally have been known to obscure the detection of skin cancer. However, despite being a ben ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blemish
Blemish may refer to: * Acne, skin imperfections * Blemish (album), ''Blemish'' (album), a 2003 album by David Sylvian See also * Flaw (other) * Imperfect (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Senescence
Cellular senescence is a phenomenon characterized by the cessation of cell division. In their experiments during the early 1960s, Leonard Hayflick and Paul Moorhead found that normal human fetal fibroblasts in culture reach a maximum of approximately 50 cell population doublings before becoming senescent. This process called the Hayflick limit is also known as "replicative senescence", since it is brought about through replication. Hayflick's discovery of mortal cells paved the path for the discovery and understanding of cellular aging molecular pathways. Cellular senescence can be initiated by a wide variety of stress inducing factors. These stress factors include both environmental and internal damaging events, abnormal cellular growth, oxidative stress, autophagy factors, among many other things. The physiological importance for cell senescence has been attributed to prevention of carcinogenesis, and more recently, aging, development, and tissue repair. Senescent cells c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Signs Of Ageing
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External may refer to: * Externality, in economics, the cost or benefit that affects a party who did not choose to incur that cost or benefit * Externals, a fictional group of X-Men antagonists See also * *Internal (other) Internal may refer to: *Internality as a concept in behavioural economics *Neijia, internal styles of Chinese martial arts *Neigong or "internal skills", a type of exercise in meditation associated with Daoism * ''Internal'' (album) by Safia, 2016 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Cutaneous Conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the Human body, body and composed of Human skin, skin, hair, Nail (anatomy), nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square metres, and is made of three distinct layers: the epidermis (skin), epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin.Burns, Tony; ''et al''. (2006) ''Rook's Textbook of Dermatology CD-ROM''. Wiley-Blackwell. . Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. Embryology, In the embryo, the epidermis, hair, and glands form from the ectod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lentigo
A lentigo () (plural lentigines, ) is a small pigmented spot on the skin with a clearly defined edge, surrounded by normal-appearing skin. It is a harmless (benign) hyperplasia of melanocytes which is linear in its spread. This means the hyperplasia of melanocytes is restricted to the cell layer directly above the basement membrane of the epidermis where melanocytes normally reside. This is in contrast to the "nests" of multi-layer melanocytes found in moles (melanocytic nevi). Because of this characteristic feature, the adjective "lentiginous" is used to describe other skin lesions that similarly proliferate linearly within the basal cell layer.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. p. 1101. .''Robbins and Cotran Pathologic Basis of Disease'' Elsevier. 2005. p. 1232. . Diagnosis Conditions characterized by lentigines include: * Lentigo simplex * Solar lentigo (Liver spots) * PUVA lentigines * Ink spot lentigo * LEOPARD syndrome * Muc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freckle
Freckles are clusters of concentrated melaninized cells which are most easily visible on people with a fair complexion. Freckles do not have an increased number of the melanin-producing cells, or melanocytes, but instead have melanocytes that overproduce melanin granules (melanosomes) changing the coloration of the outer skin cells (keratinocytes). As such, freckles are different from lentigines and moles, which are caused by accumulation of melanocytes in a small area. Freckles can appear on all types of skin tones. Of the six Fitzpatrick skin types, they are most common on skin tones 1 and 2, which usually belong to North Europeans. However, it can also be found on people all over the world. In England a historical term for freckles is summer-voys, sometimes spelt summervoise, which may be related to the German term ''Sommersprossen''. Biology The formation of freckles is caused by exposure to sunlight. The exposure to UV-B radiation activates melanocytes to increase melanin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryosurgery
Cryosurgery (with ''cryo'' from the Ancient Greek ) is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions. History In 1841, English physician James Arnott described therapeutic applications of extremely cold temperatures, namely a mixture of crushed ice and salt applied locally (to skin or mucous membrane). He theorized his technique was capable of "arresting the accompanying inflammation, and perhaps destroying the vitality of the cancer cell." His works were the first to hypothesize that extreme cold could be used to selectively damage or destroy harmful tissue. Uses Warts, moles, skin tags, solar keratoses, molluscum, Morton's neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Nitrogen
Liquid nitrogen (LN2) is nitrogen in a liquid state at cryogenics, low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, mobile liquid whose viscosity is about one-tenth that of acetone (i.e. roughly one-thirtieth that of water at room temperature). Liquid nitrogen is widely used as a coolant. Physical properties The diatomic character of the N2 molecule is retained after liquefaction. The weak van der Waals interaction between the N2 molecules results in little interatomic attraction. This is the cause of nitrogen's unusually low boiling point. The temperature of liquid nitrogen can readily be reduced to its freezing point by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of nitrogen gas bubbles. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoid
The retinoids are a class of chemical compounds that are natural derivatives of vitamin A or are chemically related to it. Synthetic retinoids are utilized in cosmetic formulations, clinical dermatology, and the treatment of some forms of cancer. Retinoids have many important functions throughout the body, including in vision, regulation of skin proliferation and differentiation, growth of bone tissue, immune function, and male fertility. The biology of retinoids is complex, having well-documented effectiveness in the management of conditions ranging from acute promyelocytic leukemia to acne to photoaging. On the other hand, retinoids may be involved in metabolic dysfunction and, at least in some forms, carcinogenesis. Types Retinoids are divided into four generations based on their molecular structure and receptor selectivity. Structure The basic structure of the hydrophobic retinoid molecule consists of a cyclic end group, a polyene side chain and a polar end group. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Hydroxy Acid
Alpha hydroxy carboxylic acids, or α-hydroxy carboxylic acids (AHAs), are a group of carboxylic acids featuring a hydroxy group located ''one'' carbon atom away from the acid group. This structural aspect distinguishes them from beta hydroxy acids, where the functional groups are separated by ''two'' carbon atoms. Notable AHAs include glycolic acid, lactic acid, mandelic acid, and citric acid. α-Hydroxy acids are stronger acids compared to their non-alpha hydroxy counterparts, a property enhanced by internal hydrogen bonding. AHAs serve a dual purpose: industrially, they are utilized as additives in animal feed and as precursors for polymer synthesis. In cosmetics, they are commonly used for their ability to chemically exfoliate the skin. Occurrence Aldonic acids, a type of sugar acid, are a class of naturally occurring hydroxycarboxylic acids. They have the general chemical formula, HO2C(CHOH)''n''CH2OH. Gluconic acid, a particularly common aldonic acid, the oxidized deriv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermis
The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), 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 Ground substance, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromal Cell-derived Factor 1
The stromal cell-derived factor 1 (SDF-1), also known as C-X-C motif chemokine 12 (CXCL12), is a chemokine protein that in humans is encoded by the ''CXCL12'' gene on chromosome 10. It is ubiquitously expressed in many tissues and cell types. Stromal cell-derived factors 1-alpha and 1-beta are small cytokines that belong to the chemokine family, members of which activate leukocytes and are often induced by proinflammatory stimuli such as lipopolysaccharide, TNF, or IL1. The chemokines are characterized by the presence of 4 conserved cysteines that form 2 disulfide bonds. They can be classified into 2 subfamilies. In the CC subfamily, the cysteine residues are adjacent to each other. In the CXC subfamily, they are separated by an intervening amino acid. The SDF1 proteins belong to the latter group. CXCL12 signaling has been observed in several cancers. The ''CXCL12'' gene also contains one of 27 SNPs associated with increased risk of coronary artery disease. Structure Gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
