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Osteoma Cutis
Osteoma cutis is a cutaneous condition characterized by the presence of bone within the skin in the absence of a preexisting or associated lesion. Osteoma cutis often manifests as solid, varying-sized, skin-colored subcutaneous nodules. Signs and symptoms Osteoma cutis can present clinically as a single, asymptomatic lesion or as many lesions, depending on the circumstances. Their sizes vary from 0.1 to 5.0 cm. These lesions might show up as miliary lesions, papules, plaques, or nodules. They feel firm to the touch and might occasionally be the cause of yellowish or white spots on the skin. Bony spicules may occasionally be released from an ulcerated layer of skin above the epidermis. Causes There are two types of osteoma cutis: primary and secondary. When an osteoma cutis does not have an underlying lesion, it is categorized as primary. Primary osteoma cutis can arise alone or in combination with metabolic syndrome. When osteoma cutis is linked to neoplasia, dysembryoplasia, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Papule
A papule is a small, well-defined bump in the skin lesion, skin. It may have a rounded, pointed or flat top, and may have a umbilication, dip. It can appear with a Peduncle (anatomy), stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some have Crust (dermatology), crusts or Scale (dermatology), scales. A papule can be flesh colored, yellow, white, brown, red, blue or purplish. There may be just one or many, and they may occur irregularly in different parts of the body or appear in clusters. It does not contain fluid but may progress to a pustule or vesicle (dermatology), vesicle. A papule is smaller than a Nodule (medicine), nodule; it can be as tiny as a pinhead and is typically less than 1 cm in width, according to some sources, and 0.5 cm according to others. When merged together, it appears as a plaque. A papule's colour might indicate its cause, such as white in Milium (dermatology), milia, red in eczema, yellowish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesenchymal Cells
Mesenchymal stem cells (MSCs), also known as mesenchymal stromal cells or medicinal signaling cells, are multipotent stromal cells that can differentiate into a variety of cell types, including osteoblasts (bone cells), chondrocytes (cartilage cells), myocytes (muscle cells) and adipocytes (fat cells which give rise to marrow adipose tissue). The primary function of MSCs is to respond to injury and infection by secreting and recruiting a range of biological factors, as well as modulating inflammatory processes to facilitate tissue repair and regeneration. Extensive research interest has led to more than 80,000 peer-reviewed papers on MSCs. Structure Definition Mesenchymal stem cells (MSCs), a term first used (in 1991) by Arnold Caplan at Case Western Reserve University, are characterized morphologically by a small cell body with long, thin cell processes. While the terms ''mesenchymal stem cell'' (MSC) and ''marrow stromal cell'' have been used interchangeably for many years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcinosis Cutis
Calcinosis cutis is an uncommon condition marked by calcium buildup in the skin and subcutaneous tissues. Calcinosis cutis can range in intensity from little nodules in one area of the body to huge, crippling lesions affecting a vast portion of the body. Five kinds of the condition are typically distinguished: calciphylaxis, idiopathic calcification, iatrogenic calcification, dystrophic calcification, and metastatic calcification. Tumors, inflammation, varicose veins, infections, connective tissue disease, hyperphosphatemia, and hypercalcemia can all lead to calcinosis. Systemic sclerosis is linked to calcineuris cutis. Calcinosis is seen in Limited Cutaneous Systemic Sclerosis, also known as CREST syndrome (the "C" in CREST). Signs and symptoms Lesions might be more severe and widespread, or they can develop gradually and show no symptoms. The nodules may cause pain and hinder function in addition to having a variety of sizes and shapes. The underlying condition determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon-dioxide Laser
The carbon-dioxide laser (CO2 laser) was one of the earliest gas lasers to be developed. It was invented by Kumar Patel of Bell Labs in 1964 and is still one of the most useful types of laser. Carbon-dioxide lasers are the highest-power continuous-wave lasers that are currently available. They are also quite efficient: the ratio of output power to pump power can be as large as 20%. The CO2 laser produces a beam of infrared light with the principal wavelength bands centering on 9.6 and 10.6 micrometers (μm). Amplification The active laser medium (laser gain/ amplification medium) is a gas discharge which is air- or water-cooled, depending on the power being applied. The filling gas within a sealed discharge tube consists of around 10–20% carbon dioxide (), around 10–20% nitrogen (), a few percent hydrogen () and/or xenon (Xe), with the remainder being helium (He). A different mixture is used in a ''flow-through'' laser, where is continuously pumped through it. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermabrasion
Dermabrasion is a type of surgical skin planing, generally with the goal of removing acne, scarring and other skin or tissue irregularities, typically performed in a professional medical setting by a dermatologist or plastic surgeon trained specifically in this procedure. Dermabrasion has been practiced for many years (before the advent of lasers) and involves the controlled deeper abrasion (wearing away) of the upper to mid layers of the skin with any variety of strong abrasive devices including a wire brush, diamond wheel or fraise, sterilized sandpaper, salt crystals or other mechanical means. Dermabrasion procedures are surgical, invasive procedures that typically require a local anaesthetic. Often, they are performed in surgical suites or in professional medical centers. Since the procedure can typically remove the top to deeper layers of the epidermis and extend into the reticular dermis, there is always minor skin bleeding. The procedure carries risks of scarring, skin d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tretinoin
Tretinoin, also known as all-''trans'' retinoic acid (ATRA), is a medication used for the treatment of acne and acute promyelocytic leukemia. For acne, it is applied to the skin as a cream, gel or ointment. For acute promyelocytic leukemia, it is effective only when the RARA-PML fusion mutation is present and is taken by mouth for up to three months. Topical tretinoin is also the most extensively investigated retinoid therapy for photoaging. Common side effects when used as a cream are limited to the skin and include skin redness, peeling, and sun sensitivity. When taken by mouth, side effects include hypertriglyceridemia, hypercholesterolemia, shortness of breath, headache, numbness, depression, skin dryness, itchiness, hair loss, vomiting, muscle pains, and vision changes. Other severe side effects include high white blood cell counts and blood clots. Use during pregnancy is contraindicated due to the risk of birth defects. It is in the retinoid family of medications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Marrow
Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of Blood cell, hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the Rib cage, ribs, vertebrae, sternum, and Pelvis, bones of the pelvis. Bone marrow comprises approximately 5% of total body mass in healthy adult humans, such that a person weighing 73 kg (161 lbs) will have around 3.7 kg (8 lbs) of bone marrow. Human marrow produces approximately 500 billion blood cells per day, which join the Circulatory system, systemic circulation via permeable vasculature sinusoids within the medullary cavity. All types of Hematopoietic cell, hematopoietic cells, including both Myeloid tissue, myeloid and Lymphocyte, lymphoid lineages, are create ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haversian Systems
In osteology, the osteon or haversian system (; named for Clopton Havers) is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically between 0.25 mm and 0.35 mm in diameter. Their length is often hard to define, but estimates vary from several millimeters"Osteon," ''Encyclopædia Britannica Online'' (2009); retrieved 23 June 2009. to around 1 centimeter. They are present in many bones of most mammals and some bird, reptile, and amphibian species. Histogenesis The Haversian system forms during the process of endochondral ossification, which starts with a cartilage template that is gradually replaced by bone tissue. Osteoblasts, the bone-forming cells, secrete the organic components of bone matrix steoidand then initiates its mineralization. As osteoblasts become surrounded by the bone matrix, they differentiate into osteocytes, which reside in the lacunae and maintain bone tissue. The osteocytes connect to each other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoclast
An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and bone remodeling, remodeling of bones of the vertebrate, vertebral skeleton. The osteoclast disassembles and digests the composite of hydrated protein and mineral at a molecular level by secreting acid and a collagenase, a process known as ''bone resorption''. This process also helps regulate the level of blood calcium. Osteoclasts are found on those surfaces of bone that are undergoing resorption. On such surfaces, the osteoclasts are seen to be located in shallow depressions called ''resorption bays (Howship's lacunae)''. The resorption bays are created by the erosive action of osteoclasts on the underlying bone. The border of the lower part of an osteoclast exhibits finger-like processes due to the presence of deep infoldings of the cell membrane; this border is called ''ruffled border''. The ruffled border lies in contact with the bone surface within a ... [...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] |
Osteoblast
Osteoblasts (from the Greek combining forms for " bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cells with a single nucleus that synthesize bone. However, in the process of bone formation, osteoblasts function in groups of connected cells. Individual cells cannot make bone. A group of organized osteoblasts together with the bone made by a unit of cells is usually called the osteon. Osteoblasts are specialized, terminally differentiated products of mesenchymal stem cells. They synthesize dense, crosslinked collagen and specialized proteins in much smaller quantities, including osteocalcin and osteopontin, which compose the organic matrix of bone. In organized groups of disconnected cells, osteoblasts produce hydroxyapatite, the bone mineral, that is deposited in a highly regulated manner, into the inorganic matrix forming a strong and dense mineralized tissue, the mineralized matrix. Hydroxyapatite-coated bone implants often perfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nodule (medicine)
In medicine, nodules are small firm lumps, usually greater than 1 cm in diameter. If filled with fluid they are referred to as cysts. Smaller (less than 0.5 cm) raised soft tissue bumps may be termed papules. The evaluation of a skin nodule includes a description of its appearance, its location, how it feels to touch and any associated symptoms which may give clues to an underlying medical condition. Nodules in skin include dermatofibroma and pyogenic granuloma. Nodules may form on tendons and muscles in response to injury, and are frequently found on vocal cords. They may occur in organs such as the lung, or thyroid, or be a sign in other medical conditions such as rheumatoid arthritis. Characteristics Nodules are small firm lumps usually greater than 1 cm in diameter, found in skin and other organs. If filled with fluid they are usually softer and referred to as cysts. Smaller (less than 0.5 cm) raised soft tissue bumps may be termed papules. Eva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
