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TRPV6
TRPV6 is a membrane calcium (Ca2+) channel protein which is particularly involved in the first step in Ca2+absorption in the intestine. Classification Transient Receptor Potential Vanilloid subfamily member 6 (TRPV6) is an epithelial Ca2+ channel that belongs to the transient receptor potential family (TRP) of proteins. The TRP family is a group of channel proteins critical for ionic homeostasis and the perception of various physical and chemical stimuli. TRP channels can detect temperature, osmotic pressure, olfaction, taste, and mechanical forces. The human genome encodes for 28 TRP channels, which include six TRPV channels. The high Ca2+-selectivity of TRPV5 and TRPV6 makes these channels distinct from the other four TRPV channels (TRPV1-TRPV4). TRPV5 and TRPV6 are involved in Ca2+ transport, whereas TRPV1 through TRPV3 are heat sensors with different temperature threshold for activation, and TRPV4 is involved in sensing osmolarity. Genetic defects in TRPV6 gene are linked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRPV5
Transient receptor potential cation channel subfamily V member 5 is a calcium channel protein that in humans is encoded by the ''TRPV5'' gene. Function The ''TRPV5'' gene is a member of the transient receptor family and the TRPV subfamily. The calcium-selective channel, TRPV5, encoded by this gene has 6 transmembrane-spanning domains, multiple potential phosphorylation sites, an N-linked glycosylation site, and 5 ANK repeats. This protein forms homotetramers or heterotetramers and is activated by a low internal calcium level. Both TRPV5 and TRPV6 are expressed in kidney and intestinal epithelial cells. TRPV5 is mainly expressed in kidney epithelial cells, where it plays an important role in the reabsorption of Ca2+, whereas TRPV6 is mainly expressed in the intestine. The enzyme α-klotho increases kidney calcium reabsorption by stabilizing TPRV5. Klotho is a beta-glucuronidase-like enzyme that activates TRPV5 by removal of sialic acid. Clinical significance Normally, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Metabolism
Calcium metabolism is the movement and regulation of calcium ions (Ca2+) ''in'' (via the gut) and ''out'' (via the gut and kidneys) of the body, and ''between'' body compartments: the blood plasma, the extracellular and intracellular fluids, and bone. Bone acts as a calcium storage center for deposits and withdrawals as needed by the blood via continual bone remodeling. An important aspect of calcium metabolism is plasma calcium homeostasis, the regulation of calcium ions in the blood plasma within narrow limits. The level of the calcium in plasma is regulated by the hormones parathyroid hormone (PTH) and calcitonin. PTH is released by the chief cells of the parathyroid glands when the plasma calcium level falls below the normal range in order to raise it; calcitonin is released by the parafollicular cells of the thyroid gland when the plasma level of calcium is above the normal range in order to lower it. Body compartment content Calcium is the most abundant mineral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRPV
TRPV is a family of transient receptor potential cation channels (TRP channels) in animals. All TRPVs are highly calcium selective. TRP channels are a large group of ion channels consisting of six protein families, located mostly on the plasma membrane of numerous human and animal cell types, and in some fungi. TRP channels were initially discovered in the ''trp'' mutant strain of the fruit fly '' Drosophila'' that displayed transient elevation of potential in response to light stimuli, and were therefore named "transient receptor potential" channels. The name now refers only to a family of proteins with similar structure and function, not to the mechanism of their activation. Later, TRP channels were found in vertebrates where they are ubiquitously expressed in many cell types and tissues. There are about 28 TRP channels that share some structural similarity to each other. These are grouped into two broad groups: group 1 includes TRPC ( "C" for canonical), TRPV ("V" for vanil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transient Receptor Potential Channel
Transient receptor potential channels (TRP channels) are a group of ion channels located mostly on the plasma membrane of numerous animal cell types. Most of these are grouped into two broad groups: Group 1 includes TRPC ( "C" for canonical), TRPV ("V" for vanilloid), TRPVL ("VL" for vanilloid-like), TRPM ("M" for melastatin), TRPS ("S" for soromelastatin), TRPN ("N" for no mechanoreceptor potential C), and TRPA ("A" for ankyrin). Group 2 consists of TRPP ("P" for polycystic) and TRPML ("ML" for mucolipin). Other less-well categorized TRP channels exist, including yeast channels and a number of Group 1 and Group 2 channels present in non-animals. Many of these channels mediate a variety of sensations such as pain, temperature, different kinds of tastes, pressure, and vision. In the body, some TRP channels are thought to behave like microscopic thermometers and used in animals to sense hot or cold. Some TRP channels are activated by molecules found in spices like garlic (alli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoarthritis
Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the world. The most common symptoms are joint pain and stiffness. Usually the symptoms progress slowly over years. Initially they may occur only after exercise but can become constant over time. Other symptoms may include joint swelling, decreased range of motion, and, when the back is affected, weakness or numbness of the arms and legs. The most commonly involved joints are the two near the ends of the fingers and the joint at the base of the thumbs; the knee and hip joints; and the joints of the neck and lower back. Joints on one side of the body are often more affected than those on the other. The symptoms can interfere with work and normal daily activities. Unlike some other types of arthritis, only the joints, not internal organs, are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Male Infertility
Male infertility refers to a sexually mature male's inability to impregnate a fertile female. In humans it accounts for 40–50% of infertility. It affects approximately 7% of all men. Male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity. More recently, advance sperm analyses that examine intracellular sperm components are being developed. Age considerations There is a decrease in sperm concentration as men age: 90% of seminiferous tubules in men in their 20s and 30s contain spermatids, whereas men in their 40s and 50s have spermatids in 50% of their seminiferous tubules, and only 10% of seminiferous tubules from men aged > 80 years contain spermatids. In a random international sample of 11,548 men confirmed to be biological fathers by DNA paternity testing, the oldest father was found to be 66 years old at the birth of his child; the ratio of DNA-confirmed versus DNA-rejected paternity tests around tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pendred Syndrome
Pendred syndrome is a genetic disorder leading to congenital bilateral (both sides) sensorineural hearing loss and goitre with euthyroid or mild hypothyroidism (decreased thyroid gland function). There is no specific treatment, other than supportive measures for the hearing loss and thyroid hormone supplementation in case of hypothyroidism. It is named after Vaughan Pendred (1869–1946), the British doctor who first described the condition in an Irish family living in Durham in 1896. It accounts for 7.5% to 15% of all cases of congenital deafness. Signs and symptoms The hearing loss of Pendred syndrome is often, although not always, present from birth, and language acquisition may be a significant problem if deafness is severe in childhood. The hearing loss typically worsens over the years, and progression can be step-wise and related to minor head trauma. In some cases, language development worsens after head injury, demonstrating that the inner ear is sensitive to traum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. In the developing world, 15% of cancers are due to infections such as '' Helicobacter pylori'', hepatitis B, hepatitis C, human papillomavirus infection, Epstein–Barr virus and human immunodeficiency virus (HIV). These factors act, at least partly, by changing the genes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Channel
A calcium channel is an ion channel which shows selective permeability to calcium ions. It is sometimes synonymous with voltage-gated calcium channel, although there are also ligand-gated calcium channels. Comparison tables The following tables explain gating, gene, location and function of different types of calcium channels, both voltage and ligand-gated. Voltage-gated Ligand-gated *the ''receptor-operated calcium channels'' (in vasoconstriction) **P2X receptors Page 479 Pharmacology L-type calcium channel blockers are used to treat hypertension. In most areas of the body, depolarization is mediated by sodium influx into a cell; changing the calcium permeability has little effect on action potentials. However, in many smooth muscle tissues, depolarization is mediated primarily by calcium influx into the cell. L-type calcium channel blockers selectively inhibit these action potentials in smooth muscle which leads to dilation of blood vessels; this in turn corrects hypert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine may be used instead of duodenum. In mammals the duodenum may be the principal site for iron absorption. The duodenum precedes the jejunum and ileum and is the shortest part of the small intestine. In humans, the duodenum is a hollow jointed tube about 25–38 cm (10–15 inches) long connecting the stomach to the jejunum, middle part of the small intestine. It begins with the duodenal bulb and ends at the suspensory muscle of duodenum. Duodenum can be divided into four parts: the first (superior), the second (descending), the third (horizontal) and the fourth (ascending) parts. Structure The duodenum is a C-shaped structure lying adjacent to the stomach. It is divided anatomically into four sections. The first part of the duoden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratinocyte
Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the basal layer (''stratum basale'') of the skin are sometimes referred to as basal keratinocytes. Keratinocytes form a barrier against environmental damage by heat, UV radiation, water loss, pathogenic bacteria, fungi, parasites, and viruses. A number of structural proteins, enzymes, lipids, and antimicrobial peptides contribute to maintain the important barrier function of the skin. Keratinocytes differentiate from epidermal stem cells in the lower part of the epidermis and migrate towards the surface, finally becoming corneocytes and eventually be shed off, which happens every 40 to 56 days in humans. Function The primary function of keratinocytes is the formation of a barrier against environmental damage by heat, UV radiation, water loss, pathogenic bacteria, fungi, parasites, and viruses. Pathogens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
