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Channelopathy
Channelopathies are a group of diseases caused by the dysfunction of ion channel subunits or their interacting proteins. These diseases can be inherited or acquired by other disorders, drugs, or toxins. Mutations in genes encoding ion channels, which impair channel function, are the most common cause of channelopathies. There are more than 400 genes that encode ion channels, found in all human cell types and are involved in almost all physiological processes. Each type of channel is a multimeric complex of subunits encoded by a number of genes. Depending where the mutation occurs it may affect the gating, conductance, ion selectivity, or signal transduction of the channel. Channelopathies can be categorized based on the organ system which they are associated with. In the cardiovascular system, the electrical impulse needed for each heartbeat is made possible by the electrochemical gradient of each heart cell. Because the heartbeat is dependent on the proper movement of ions across ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiology
Cardiology () is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a sub-specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery. Specializations All cardiologists in the branch of medicine study the disorders of the heart, but the study of adult and child heart disorders each require different training pathways. Therefore, an adult cardiologist (often simply called "cardiologist") is inadequately trained to take care of children, and pediatric cardiologists are not trained to treat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myotonia Congenita
''Myotonia congenita'' is a congenital neuromuscular channelopathy that affects skeletal muscles (muscles used for movement). It is a genetic disorder. The hallmark of the disease is the failure of initiated contraction to terminate, often referred to as delayed relaxation of the muscles (myotonia) and rigidity. Symptoms include delayed relaxation of the muscles after voluntary contraction (myotonia), and may also include stiffness, hypertrophy (enlargement), transient weakness in some forms of the disorder (from certain genetic mutations), severe masseter spasm, and cramping. The condition is sometimes referred to as fainting goat syndrome, as it is responsible for the eponymous 'fainting' seen in fainting goats when presented with a sudden stimulus. Of note, ''myotonia congenita'' has no association with malignant hyperthermia (MH). Symptoms and signs The prolonged muscle contractions, which occur most commonly in the leg muscles in recessive mutations, and more commonly in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemical Gradient
An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts: * The chemical gradient, or difference in Concentration, solute concentration across a membrane. * The electrical gradient, or difference in Electric charge, charge across a membrane. If there are unequal concentrations of an ion across a permeable membrane, the ion will move across the membrane from the area of higher concentration to the area of lower concentration through Molecular diffusion, simple diffusion. Ions also carry an electric charge that forms an electric potential across a membrane. If there is an unequal distribution of charges across the membrane, then the difference in electric potential generates a force that drives ion diffusion until the charges are balanced on both sides of the membrane. Electrochemical gradients are essential to the operation of Electric battery, batteries and other electrochemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 activated by phosphatidylinositol 4,5-bisphosphate (Phosphatidylinositol 4,5-bisphosphate, PIP2). The malfunction of the channels has been implicated in several diseases. IRK channels possess a pore domain, homologous to that of voltage-gated ion channels, and flanking transmembrane domain, transmembrane segments (TMSs). They may exist in the membrane as Homo-oligomer, homo- or Hetero-oligomers, heterooligomers and each monomer possesses between 2 and 4 TMSs. In terms of function, these proteins transport potassium, potassium (K+), with a greater tendency for K+ uptake than K+ export. The process of inward-rectification was discovered by Denis Noble in cardiac muscle cells in 1960s and by Richard Adrian, 2nd Baron Adrian, Richard Adrian and Ala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Hyperinsulinism
Congenital hyperinsulinism (HI or CHI) is a condition causing severe Neonatal hypoglycemia, hypoglycemia (low blood sugar) in newborns due to the overproduction of insulin. There are various causes of HI, some of which are known to be the result of a Mutation, genetic mutation. Sometimes HI occurs on its own (isolated) and more rarely associated with other medical conditions (as a syndrome). Congenital forms of hyperinsulinism can be transient (short-term) or persistent (long-term) and mild or severe. It can be the result of a defect in the entire pancreas (diffuse HI) or in just part of the pancreas (focal HI). Irrespective of the form, cause, or type, HI is a medical emergency that must be managed from its onset. There is no other hypoglycemic condition in the newborn period as dangerous as HI. Left untreated, hypoglycemia from HI can cause developmental disorders, seizures, permanent brain damage, and even death. For those with focal HI, there is the potential for a cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ryanodine Receptor 2
Ryanodine receptor 2 (RYR2) is one of a class of ryanodine receptors and a protein found primarily in cardiac muscle. In humans, it is encoded by the ''RYR2'' gene. In the process of cardiac calcium-induced calcium release, RYR2 is the major mediator for sarcoplasmic release of stored calcium ions. Structure The channel is composed of RYR2 homotetramers and FK506-binding proteins found in a 1:4 stoichiometric ratio. Calcium channel function is affected by the specific type of FK506 isomer interacting with the RYR2 protein, due to binding differences and other factors. Function The RYR2 protein functions as the major component of a calcium channel located in the sarcoplasmic reticulum that supplies ions to the cardiac muscle during systole. To enable cardiac muscle contraction, calcium influx through voltage-gated L-type calcium channels in the plasma membrane allows calcium ions to bind to RYR2 located on the sarcoplasmic reticulum. This bindi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catecholaminergic Polymorphic Ventricular Tachycardia
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited genetic disorder that predisposes those affected to potentially life-threatening abnormal heart rhythms or arrhythmias. The arrhythmias seen in CPVT typically occur during exercise or at times of emotional stress, and classically take the form of bidirectional ventricular tachycardia or ventricular fibrillation. Those affected may be asymptomatic, but they may also experience blackouts or even sudden cardiac death. CPVT is caused by genetic mutations affecting proteins that regulate the concentrations of calcium within cardiac muscle cells. The most commonly identified gene is RYR2, which encodes a protein included in an ion channel known as the ryanodine receptor; this channel releases calcium from a cell's internal calcium store, the sarcoplasmic reticulum, during every heartbeat. CPVT is often diagnosed from an ECG recorded during an exercise tolerance test, but it may also be diagnosed with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bartter Syndrome
Bartter syndrome (BS) is a rare inherited disease characterised by a defect in the thick ascending limb of the loop of Henle, which results in low potassium levels (hypokalemia), increased blood pH (alkalosis), and normal to low blood pressure. There are two types of Bartter syndrome: neonatal and classic. A closely associated disorder, Gitelman syndrome, is milder than both subtypes of Bartter syndrome. Signs and symptoms In 90% of cases, neonatal Bartter syndrome is seen between 24 and 30 weeks of gestation with excess amniotic fluid (polyhydramnios). After birth, the infant is seen to urinate and drink excessively (polyuria, and polydipsia, respectively). Life-threatening dehydration may result if the infant does not receive adequate fluids. About 85% of infants dispose of excess amounts of calcium in the urine (hypercalciuria) and kidneys ( nephrocalcinosis), which may lead to kidney stones. In rare occasions, the infant may progress to kidney failure. Patients with classic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Sclerosis
Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit signals, resulting in a range of signs and symptoms, including physical, cognitive disability, mental, and sometimes psychiatric problems. Symptoms include double vision, vision loss, eye pain, muscle weakness, and loss of Sensation (psychology), sensation or coordination. MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms). In relapsing forms of MS, symptoms may disappear completely between attacks, although some permanent neurological problems often remain, especially as the disease advances. In progressive forms of MS, bodily function slowly deteriorates once symptoms manifest and will steadily worsen if left untreated. While its cause is unclear, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptopathy
A synaptopathy is a disease of the brain, spinal cord or peripheral nervous system relating to the dysfunction of synapses. This can arise as a result of a mutation in a gene encoding a synaptic protein such as an ion channel, neurotransmitter receptor, or a protein involved in neurotransmitter release. It can also arise as a result of an autoantibody targeting a synaptic protein. Synaptopathies caused by ion channel mutations are also known as synaptic channelopathies. An example is episodic ataxia. Myasthenia gravis is an example of an autoimmune synaptopathy. Some toxins also affect synaptic function. Tetanus toxin and botulinum toxin affect neurotransmitter release. Tetanus toxin can enter the body via a wound, and botulinum toxin can be ingested or administered therapeutically to alleviate dystonia or as cosmetic treatment. Another example of synaptopathy occurs in the auditory system. This cochlear synaptopathy has been seen after prolonged noise exposure in both primate a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
