|
Ischemic Preconditioning
Ischemic preconditioning (IPC) is an experimental technique for producing resistance to the loss of blood supply, and thus oxygen, to tissues of many types. In the heart, IPC is an intrinsic process whereby repeated short episodes of ischaemia protect the myocardium against a subsequent ischaemic insult. It was first identified in 1986 by Murry ''et al.'' This group exposed anesthetised open-chest dogs to four periods of 5 minute coronary artery occlusions followed by a 5-minute period of reperfusion before the onset of a 40-minute sustained occlusion of the coronary artery. The control animals had no such period of “ischaemic preconditioning” and had much larger infarct sizes compared with the dogs that did. The exact molecular pathways behind this phenomenon have yet to be fully understood. Background If the blood supply to an organ or a tissue is impaired for a short time (usually less than five minutes) then restored so that blood flow is resumed, and the process repeat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains proteins, glucose, mineral ions, and hormones. The blood cells are mainly red blood cells (erythrocytes), white blood cells (leukocytes), and (in mammals) platelets (thrombocytes). The most abundant cells are red blood cells. These contain hemoglobin, which facilitates oxygen transport by reversibly binding to it, increasing its solubility. Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Blood is circulated around the body through blood vessels by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Percutaneous Coronary Intervention
Percutaneous coronary intervention (PCI) is a minimally invasive non-surgical procedure used to treat stenosis, narrowing of the coronary artery, coronary arteries of the heart found in coronary artery disease. The procedure is used to place and deploy coronary stents, a permanent wire-meshed tube, to open narrowed coronary arteries. PCI is considered 'non-surgical' as it uses a small hole in a peripheral artery (leg/arm) to gain access to the arterial system; an equivalent surgical procedure would involve the opening of the chest wall to gain access to the heart area. The term 'coronary angioplasty with stent' is synonymous with PCI. The procedure visualises the blood vessels via Fluoroscopy, fluoroscopic imaging and contrast dyes. PCI is performed by an interventional cardiologists in a catheterization laboratory setting. Patients who undergo PCI broadly fall into two patient groups. Those who are suffering from a heart attack and are in a critical care emergency room setting an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hypercholesterolemia
Hypercholesterolemia, also called high cholesterol, is the presence of high levels of cholesterol in the blood. It is a form of hyperlipidemia (high levels of lipids in the blood), hyperlipoproteinemia (high levels of lipoproteins in the blood), and dyslipidemia (any abnormalities of lipid and lipoprotein levels in the blood). Elevated levels of non-HDL cholesterol and LDL in the blood may be a consequence of diet, obesity, inherited (genetic) diseases (such as LDL receptor mutations in familial hypercholesterolemia), or the presence of other diseases such as type 2 diabetes and an underactive thyroid. Cholesterol is one of three major classes of lipids produced and used by all animal cells to form membranes. Plant cells manufacture phytosterols (similar to cholesterol) but in small quantities. Cholesterol is the precursor of the steroid hormones and bile acids. Since cholesterol is insoluble in water, it is transported in the blood plasma within protein particles ( lipop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Connexon
In biology, a connexon, also known as a connexin hemichannel, is an assembly of six proteins called connexins that form the pore for a gap junction between the cytoplasm of two adjacent cells. This channel allows for bidirectional flow of ions and signaling molecules. The connexon is the hemichannel supplied by a cell on one side of the junction; two connexons from opposing cells normally come together to form the complete intercellular gap junction channel. In some cells, the hemichannel itself is active as a conduit between the cytoplasm and the extracellular space, allowing the transference of ions and small molecules lower than 1-2 KDa. Little is known about this function of connexons besides the new evidence suggesting their key role in intracellular signaling. In still other cells connexons have been shown to occur in mitochondrial membranes and appear to play a role in heart ischaemia. Connexons made of the same type of connexins are considered homomeric, while connex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Inward Rectifier Potassium Ion Channel
Inward may refer to: * Avera and Inward, feudal services *Direct Inward Dialing, also called Direct Dial-In (DDI) in Europe and Australasia *Inward Bound (IB), running competition between the residential halls and colleges of the Australian National University *Inward investment, the injection of money from an external source into a region *''Inward Parts'', the second album by the English band ''The Others'' *Inward-rectifier potassium ion channel Inward-rectifier potassium channels (Kir, IRK) are a specific Lipid-gated_ion_channels, lipid-gated subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are acti ... (Kir, IRK), a specific subset of potassium selective ion channels * North England Inward Investment Agency, UK government sponsored agency {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Chloride Channels
Chloride channels are a superfamily of poorly understood ion channels specific for chloride. These channels may conduct many different ions, but are named for chloride because its concentration ''in vivo'' is much higher than other anions. Several families of voltage-gated channels and ligand-gated channels (e.g., the CaCC families) have been characterized in humans. Voltage-gated chloride channels perform numerous crucial physiological and cellular functions, such as controlling pH, volume homeostasis, transporting organic solutes, regulating cell migration, proliferation, and differentiation. Based on sequence homology the chloride channels can be subdivided into a number of groups. General functions Voltage-gated chloride channels are important for setting cell resting membrane potential and maintaining proper cell volume. These channels conduct or other anions such as . The structure of these channels are not like other known channels. The chloride channel subunits contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Reactive Oxygen Species
In chemistry and biology, reactive oxygen species (ROS) are highly Reactivity (chemistry), reactive chemicals formed from diatomic oxygen (), water, and hydrogen peroxide. Some prominent ROS are hydroperoxide (H2O2), superoxide (O2−), hydroxyl radical (OH.), and singlet oxygen(1O2). ROS are pervasive because they are readily produced from O2, which is abundant. ROS are important in many ways, both beneficial and otherwise. ROS function as signals, that turn on and off biological functions. They are intermediates in the redox behavior of O2, which is central to fuel cells. ROS are central to the photodegradation of organic pollutants in the atmosphere. Most often however, ROS are discussed in a biological context, ranging from their effects on aging and their role in causing dangerous genetic mutations. Inventory of ROS ROS are not uniformly defined. All sources include superoxide, singlet oxygen, and hydroxyl radical. Hydrogen peroxide is not nearly as reactive as these s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mitochondrial Permeability Transition Pore
The mitochondrial permeability transition pore (mPTP or MPTP; also referred to as PTP, mTP, or MTP) is a protein pore complex that forms in the inner mitochondrial membrane under certain pathological conditions such as traumatic brain injury, ischemia, and stroke. Opening of the pore causes an increase in the permeability of the mitochondrial membrane to solutes with a molecular mass less than 1,500 daltons, leading to loss of membrane potential, swelling of the organelle, rupture of the outer membrane, and eventual cell death. The mPTP is thought to be regulated by multiple mitochondrial proteins. Historically, Cyclophilin D and the TSPO (formerly the peripheral benzodiazepine receptor) have been considered central components. In 2025, the AAA+ ATPase protein ATAD3A was identified as a novel upstream regulator of mPTP opening. Loss of ATAD3A was shown to prevent calcium-induced pore formation and render mitochondria insensitive to cyclosporin A, suggesting it acts upstream of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
ATP-sensitive Potassium Channel
An ATP-sensitive potassium channel (or KATP channel) is a type of potassium channel that is gated by intracellular nucleotides, ATP and ADP. ATP-sensitive potassium channels are composed of Kir6.x-type subunits and sulfonylurea receptor (SUR) subunits, along with additional components. KATP channels are widely distributed in plasma membranes; however some may also be found on subcellular membranes. These latter classes of KATP channels can be classified as being either sarcolemmal ("sarcKATP"), mitochondrial ("mitoKATP"), or nuclear ("nucKATP"). Discovery and structure KATP channels were first identified in cardiac myocytes by Akinori Noma in Japan. Glucose-regulated KATP channel activity was found in pancreatic beta cells by Frances Ashcroft at the University of Oxford. The closure of KATP channels leads to increased insulin secretion in beta cells and reduces glucagon secretion in alpha cells. SarcKATP are composed of eight protein subunits ( octamer). Four of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Sarcolemma
The sarcolemma (''sarco'' (from ''sarx'') from Greek; flesh, and ''lemma'' from Greek; sheath), also called the myolemma, is the cell membrane surrounding a skeletal muscle fibre or a cardiomyocyte. It consists of a lipid bilayer and a thin outer coat of polysaccharide material ( glycocalyx) that contacts the basement membrane. The basement membrane contains numerous thin collagen fibrils and specialized proteins such as laminin that provide a scaffold to which the muscle fibre can adhere. Through transmembrane proteins in the plasma membrane, the actin skeleton inside the cell is connected to the basement membrane and the cell's exterior. At each end of the muscle fibre, the surface layer of the sarcolemma fuses with a tendon fibre, and the tendon fibres, in turn, collect into bundles to form the muscle tendons that adhere to bones. The sarcolemma generally maintains the same function in muscle cells as the plasma membrane does in other eukaryote cells. It acts as a barrie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
G-protein
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their activity is regulated by factors that control their ability to bind to and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP). When they are bound to GTP, they are 'on', and, when they are bound to GDP, they are 'off'. G proteins belong to the larger group of enzymes called GTPases. There are two classes of G proteins. The first function as monomeric small GTPases (small G-proteins), while the second function as heterotrimeric G protein complexes. The latter class of complexes is made up of ''alpha'' (Gα), ''beta'' (Gβ) and ''gamma'' (Gγ) subunits. In addition, the beta and gamma subunits can form a stable dimeric complex referred to as the beta-gamma complex . Heterotrimeric G proteins located within the cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Endogeny
Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an organism or a cell). For instance, estradiol is an endogenous estrogen hormone produced within the body, whereas ethinylestradiol Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. Ethinylestradiol was widely used for various indications such as the treatment of menopausal symptoms, gynecological ... is an exogenous synthetic estrogen, commonly used in birth control pills. In contrast, '' exogenous substances'' and ''exogenous'' ''processes'' are those that originate from outside of an organism. References External links *{{Wiktionary-inline, endogeny Biology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
