|
Lipoprotein-X
Lipoprotein-X (Lp-X) is an abnormal low density lipoprotein found in cholestasis. __TOC__ Structure Lipoprotein-X is a lamellar particle of 30 to 70 nm in diameter as revealed by electron microscopy. It is characterized by its high content of phospholipids (66% by weight) and unesterified cholesterol (22%), and its low content of protein (6%), cholesterol esters (3%), and triglycerides (3%). The protein component is dominated by albumin, located in the core, and by apolipoprotein C, located on the surface of the particle. Using zonal ultracentrifugation, lipoprotein-X can be divided into three distinct populations: Lp-X1, Lp-X2, and Lp-X3, differing in density and apolipoprotein composition. Pathogenesis The pathogenesis of lipoprotein-X in cholestasis is not totally resolved. Normally, the liver excretes lipoprotein complexes into the bile showing phospholipid and unesterified cholesterol concentrations similar to Lipoprotein-X. The in vitro incubation of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Density Lipoprotein
Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall density naming convention), very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL delivers fat molecules to Cell (biology), cells. LDL is involved in atherosclerosis, a process in which it is oxidized within the walls of Artery, arteries. Overview Lipoproteins transfer lipids (fats) around the body in the extracellular fluid, making fats available to body cells for receptor-mediated endocytosis. Lipoproteins are complex particles composed of multiple proteins, typically 80–100 proteins per particle (organized by a single apolipoprotein B for LDL and the larger particles). A single LDL particle is about 220–275 angstroms in diameter, typically transpor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholestasis
Cholestasis is a condition where bile cannot flow from the liver to the duodenum. The two basic distinctions are an obstructive type of cholestasis where there is a mechanical blockage in the duct system that can occur from a gallstone or malignancy, and metabolic types of cholestasis which are disturbances in bile formation that can occur because of genetic defects or acquired as a side effect of many medications. Classification is further divided into acute or chronic and extrahepatic or intrahepatic. Signs and symptoms The signs and symptoms of cholestasis vary according to the cause. In case of sudden onset, the disease is likely to be acute, while the gradual appearance of symptoms suggests chronic pathology. In many cases, patients may experience pain in the abdominal area. Localization of pain to the upper right quadrant can be indicative of cholecystitis or choledocholithiasis, which can progress to cholestasis. Pruritus or itching is often present in many patients with c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Microscope
An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a higher resolving power than light microscopes and can reveal the structure of smaller objects. A scanning transmission electron microscope has achieved better than 50 pm resolution in annular dark-field imaging mode and magnifications of up to about 10,000,000× whereas most light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000×. Electron microscopes use shaped magnetic fields to form electron optical lens systems that are analogous to the glass lenses of an optical light microscope. Electron microscopes are used to investigate the ultrastructure of a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipids
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine. Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science. The first phospholipid identified in 1847 as such in biological tissues was lecith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesterol
Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membranes. When chemically isolated, it is a yellowish crystalline solid. Cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Cholesterol is the principal sterol synthesized by all animals. In vertebrates, hepatic cells typically produce the greatest amounts. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as '' Mycoplasma'', which require cholesterol for growth. François Poulletier de la Salle first identified cholesterol in solid form in gallstones in 1769. However, it was not until 1815 that chemist Michel Eugène Chevreul named the compound "cholesterine". Etymology The word "cholesterol" comes from the Ancient Greek ''chole-'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triglycerides
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). 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 Triglycerides are tri-esters consisting of a glycerol bound to three fatty acid molecules. Alcohols have a hydroxyl (HO–) group. Organic acids have a carboxyl (–COOH) group. Alcohols and organic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Serum Albumin
Human serum albumin is the serum albumin found in human blood. It is the most abundant protein in human blood plasma; it constitutes about half of serum protein. It is produced in the liver. It is soluble in water, and it is monomeric. Albumin transports hormones, fatty acids, and other compounds, buffers pH, and maintains oncotic pressure, among other functions. Albumin is synthesized in the liver as preproalbumin, which has an N-terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum. The product, proalbumin, is in turn cleaved in the Golgi apparatus to produce the secreted albumin. The reference range for albumin concentrations in serum is approximately 35–50 g/L (3.5–5.0 g/dL). It has a serum half-life of approximately 21 days. It has a molecular mass of 66.5 kDa. The gene for albumin is located on chromosome 4 in locus 4q13.3 and mutations in this gene can result in anomalous proteins. The human alb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apolipoprotein
Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fats, cholesterol and fat soluble vitamins) to form lipoproteins. They transport lipids in blood, cerebrospinal fluid and lymph. The lipid components of lipoproteins are insoluble in water. However, because of their detergent-like (amphipathic) properties, apolipoproteins and other amphipathic molecules (such as phospholipids) can surround the lipids, creating a lipoprotein particle that is itself water-soluble, and can thus be carried through body fluids (i.e., blood, lymph). In addition to stabilizing lipoprotein structure and solubilizing the lipid component, apolipoproteins interact with lipoprotein receptors and lipid transport proteins, thereby participating in lipoprotein uptake and clearance. They also serve as enzyme cofactors for specific enzymes involved in the metabolism of lipoproteins. Apolipoproteins are also exploited by hepatitis C virus (HCV) to enable virus entry, assembly, and trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver
The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it is located in the quadrant (anatomy), right upper quadrant of the abdomen, below the thoracic diaphragm, diaphragm. Its other roles in metabolism include the regulation of Glycogen, glycogen storage, decomposition of red blood cells, and the production of hormones. The liver is an accessory digestive organ that produces bile, an alkaline fluid containing cholesterol and bile acids, which helps the fatty acid degradation, breakdown of fat. The gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver which is later moved to the small intestine to complete digestion. The liver's highly specialized biological tissue, tissue, consisting mostly of hepatocytes, regulates a w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bile
Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile) and stored and concentrated in the gallbladder. After eating, this stored bile is discharged into the duodenum. The composition of hepatic bile is (97–98)% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids, and lecithin), and 200 meq/L inorganic salts. The two main pigments of bile are bilirubin, which is yellow, and its oxidised form biliverdin, which is green. When mixed, they are responsible for the brown color of feces. About 400 to 800 millilitres of bile is produced per day in adult human beings. Function Bile or gall acts to some extent as a surfactant, helping to emulsify the lipids in food. Bile salt anions are hydrophilic on one side and hydrophobic on the other side; consequently, they tend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spleen
The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .σπλήν Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus Digital Library The spleen plays very important roles in regard to s (erythrocytes) and the . It removes old red blood cells and holds a reserve of blood, which can be valuable in case of |
