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Chylomicron Retention Disease
Chylomicron retention disease is a disorder of fat absorption. It is associated with SAR1B. Mutations in SAR1B prevent the release of chylomicrons in the circulation which leads to nutritional and developmental problems. It is a rare autosomal recessive disorder with around 40 cases reported worldwide. Since the disease allele is recessive, parents usually do not show symptoms. Without functional chylomicrons, certain fat-soluble vitamins such as vitamin D and vitamin E cannot be absorbed. Chylomicrons have a crucial role in fat absorption and transport, thus a deficiency in chylomicron functioning reduces available levels of dietary fats and fat-soluble vitamins. Signs and symptoms Physical symptoms of CMRD involving the development and function of the gastrointestinal tract and nervous system typically manifest between infancy and adolescence. The symptoms of CmRD are similar to the physical symptoms of malnutrition, as the disease arises due to the poor absorption of lipids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocrinology
Endocrinology (from ''endocrine system, endocrine'' + ''wikt:-logy#Suffix, -ology'') is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones. It is also concerned with the integration of developmental events proliferation, growth, and differentiation, and the psychological or behavioral activities of metabolism, human development (biology), growth and development, tissue (biology), tissue function, sleep, digestion, Respiration (physiology), respiration, excretion, mood (psychology), mood, Stress (physiology), stress, lactation, Motor coordination, movement, reproduction, and sensory perception caused by hormones. Specializations include behavioral endocrinology and comparative endocrinology. The endocrine system consists of several glands, all in different parts of the body, that secrete hormones directly into the blood rather than into a Duct (anatomy), duct system. Therefore, endocrine glands are regarde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypocholesterolemia
Hypocholesterolemia is the presence of abnormally low (''hypo-'') levels of cholesterol in the blood (''-emia''). A defect in the body's production of cholesterol can lead to adverse consequences as well. Cholesterol is an essential component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity. It is not clear if a lower than average cholesterol level is directly harmful; however, it is often encountered in particular illnesses. Presentation Role in disease With the increased use of medication to suppress cholesterol, some have expressed concern that lowering cholesterol levels excessively will itself cause disease. Specific disease entities Demographic studies suggest that cholesterol levels form a U-shape curve when plotted against mortality; this suggests that low cholesterol is associated with increased mortality, mainly due to depression, cancer, hemorrhagic stroke, aortic dissection and respiratory diseases. It is possible tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Docking (molecular)
In the field of molecular modeling, docking is a method which predicts the preferred orientation of one molecule to a second when a ligand and a target are bound to each other to form a stable complex. Knowledge of the preferred orientation in turn may be used to predict the strength of association or binding affinity between two molecules using, for example, scoring functions. The associations between biologically relevant molecules such as proteins, peptides, nucleic acids, carbohydrates, and lipids play a central role in signal transduction. Furthermore, the relative orientation of the two interacting partners may affect the type of signal produced (e.g., agonism vs antagonism). Therefore, docking is useful for predicting both the strength and type of signal produced. Molecular docking is one of the most frequently used methods in structure-based drug design, due to its ability to predict the binding-conformation of small molecule ligands to the appropriate target bind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COPII
The coat protein complex II, or COPII, is a group of proteins that facilitate the formation of vesicles to transport proteins from the endoplasmic reticulum to the Golgi apparatus or endoplasmic-reticulum–Golgi intermediate compartment. This process is termed anterograde transport, in contrast to the retrograde transport associated with the COPI complex. COPII is assembled in two parts: first an inner layer of Sar1, Sec23, and Sec24 forms; then the inner coat is surrounded by an outer lattice of Sec13 and Sec31. Function The COPII coat is responsible for the formation of vesicles from the endoplasmic reticulum (ER). These vesicles transport cargo proteins to the Golgi apparatus (in yeast) or the endoplasmic-reticulum-Golgi intermediate compartment (ERGIC, in mammals). Coat assembly is initiated when the cytosolic Ras GTPase Sar1 is activated by its guanine nucleotide exchange factor Sec12. Activated Sar1-GTP inserts itself into the ER membrane, binding preferentially to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphatic System
The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphoid organs, lymphatic tissue and lymph. Lymph is a clear fluid carried by the lymphatic vessels back to the heart for re-circulation. The Latin word for lymph, , refers to the deity of fresh water, "Lympha". Unlike the circulatory system that is a closed system, the lymphatic system is open. The human circulatory system processes an average of 20 litres of blood per day through Starling equation, capillary filtration, which removes blood plasma, plasma from the blood. Roughly 17 litres of the filtered blood is reabsorbed directly into the blood vessels, while the remaining three litres are left in the interstitial fluid. One of the main functions of the lymphatic system is to provide an accessory return route to the blood for the surplus three litres. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterocyte
Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells which line the inner surface of the small and large intestines. A glycocalyx surface coat contains digestive enzymes. Microvilli on the apical surface increase its surface area. This facilitates transport of numerous small molecules into the enterocyte from the intestinal lumen. These include broken down proteins, fats, and sugars, as well as water, electrolytes, vitamins, and bile salts. Enterocytes also have an endocrine role, secreting hormones such as leptin. Function The major functions of enterocytes include: *Ion uptake, including sodium, calcium, magnesium, iron, zinc, and copper. This typically occurs through active transport. *Water uptake. This follows the osmotic gradient established by Na+/K+ ATPase on the basolateral surface. This can occur transcellularly or paracellularly. *Sugar uptake. Polysaccharidases and disaccharidases in the glycocalyx break down large sugar molecule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipase
In biochemistry, lipase ( ) refers to a class of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually treated separately from "conventional" lipases. Unlike esterases, which function in water, lipases "are activated only when adsorbed to an oil–water interface". Lipases perform essential roles in digestion, transport and processing of dietary lipids in most, if not all, organisms. Structure and catalytic mechanism Classically, lipases catalyse the hydrolysis of triglycerides: \begin \text + \ce &\longrightarrow \text + \text \\[4pt] \text + \ce &\longrightarrow \text + \text \\[4pt] \text + \ce &\longrightarrow \text + \text \end Lipases are serine hydrolases, i.e. they function by transesterification generating an acyl serine intermediate. Most lipases act at a specific position on the glycerol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triglyceride
A triglyceride (from '' tri-'' and '' glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates as well as vegetable fat. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver and are a major component of human skin oils. Many types of triglycerides exist. One specific classification focuses on saturated and unsaturated types. Saturated fats have ''no'' C=C groups; unsaturated fats feature one or more C=C groups. Unsaturated fats tend to have a lower melting point than saturated analogues; as a result, they are often liquid at room temperature. Chemical structure The three fatty acids substituents can be the same, but they are usually different. The positions of the three fatty acids are specified using stereospecific numbering as sn-1, sn-2, and sn- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2431 Lipid Absorption
Year 431 ( CDXXXI) was a common year starting on Thursday of the Julian calendar. At the time, it was known as the Year of the Consulship of Bassus and Antiochus (or, less frequently, year 1184 ''Ab urbe condita''). The denomination 431 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Aetius campaign in the Alps: Flavius Aetius, Roman general (''magister militum''), fights the rebellion population in Rhaetia (Switzerland) and Noricum (Austria). He is attested in the city of Vindelicia (modern Augsburg), reestablishing Roman rule on the Danube frontier. * Aetius pushes the Salian Franks back across the River Somme. King Chlodio signs a peace treaty and becomes a '' foederatus'' of the Western Roman Empire. Africa * Hippo Regius becomes the capital of the Vandal Kingdom. After 14 months of hunger and disease, the Vandals ravage the cit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Missense Mutation
In genetics, a missense mutation is a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid. It is a type of nonsynonymous substitution. Missense mutations change amino acids, which in turn alter proteins and may alter a protein's function or structure. These mutations may arise spontaneously from mutagens like UV radiation, tobacco smoke, an error in DNA replication, and other factors. Screening for missense mutations can be done by sequencing the genome of an organism and comparing the sequence to a reference genome to analyze for differences. Missense mutations can be repaired by the cell when there are errors in DNA replication by using mechanisms such as DNA proofreading and DNA mismatch repair, mismatch repair. They can also be repaired by using genetic engineering technologies or pharmaceuticals. Some notable examples of human diseases caused by missense mutations are Rett syndrome, cystic fibrosis, and Sickle cell disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GTPase-activating Protein
GTPase-activating proteins or GTPase-accelerating proteins (GAPs) are a family of regulatory proteins whose members can bind to activated G proteins and stimulate their GTPase activity, with the result of terminating the signaling event. GAPs are also known as RGS protein, or RGS proteins,Kimple, A.J. "Structural Determinants of G-protein α Subunit Selectivity by Regulator of G-protein Signaling 2 (RGS2)". ''The Journal of Biological Chemistry''. 284 (2009): 19402-19411. and these proteins are crucial in controlling the activity of G proteins. Regulation of G proteins is important because these proteins are involved in a variety of important cellular processes. The large G proteins, for example, are involved in transduction of signaling from the G protein-coupled receptor for a variety of signaling processes like hormonal signaling, and small G proteins are involved in processes like cellular trafficking and cell cycling. GAP's role in this function is to turn the G protein's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanine Nucleotide Exchange Factor
Guanine nucleotide exchange factors (GEFs) are proteins or protein domains that activate monomeric GTPases by stimulating the release of guanosine diphosphate (GDP) to allow binding of guanosine triphosphate (GTP). A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity. Some GEFs can activate multiple GTPases while others are specific to a single GTPase. Function Guanine nucleotide exchange factors (GEFs) are proteins or protein domains involved in the activation of small GTPases. Small GTPases act as molecular switches in intracellular signaling pathways and have many downstream targets. The most well-known GTPases comprise the Ras superfamily and are involved in essential cell processes such as cell differentiation and proliferation, cytoskeletal organization, vesicle trafficking, and nuclear transport. GTPases are active when bound to GTP and inactive when bound to GDP, allowing their activity to be regulated by GEFs and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
