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P-glycoprotein
P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein of the cell membrane that pumps many foreign substances out of cells. More formally, it is an ATP-dependent efflux pump with broad substrate specificity. It exists in animals, fungi, and bacteria, and it likely evolved as a defense mechanism against harmful substances. P-gp is extensively distributed and expressed in the intestinal epithelium where it pumps xenobiotics (such as toxins or drugs) back into the intestinal lumen, in liver cells where it pumps them into bile ducts, in the cells of the proximal tubule of the kidney where it pumps them into urinary filtrate (in the proximal tubule), and in the capillary endothelial cells composing the blood–brain barrier and blood–testis barrier, where it pumps them back into the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABC-transporter
The ABC transporters, ATP synthase (ATP)-binding cassette transporters are a transport system superfamily that is one of the largest and possibly one of the oldest gene family, gene families. It is represented in all extant taxon, extant Phylum, phyla, from prokaryotes to humans. ABC transporters belong to translocases. ABC transporters often consist of multiple subunits, one or two of which are transmembrane proteins and one or two of which are membrane-associated AAA proteins, AAA ATPases. The ATPase subunits utilize the energy of adenosine triphosphate (ATP) binding and hydrolysis to provide the energy needed for the translocation of substrates across membranes, either for uptake or for export of the substrate. Most of the uptake systems also have an extracytoplasmic receptor, a solute binding protein. Some homologous ATPases function in non-transport-related processes such as RNA translation, translation of RNA and DNA repair. ABC transporters are considered to be an ABC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATP-binding Cassette Transporter
The ABC transporters, ATP synthase (ATP)-binding cassette transporters are a transport system superfamily that is one of the largest and possibly one of the oldest gene families. It is represented in all extant phyla, from prokaryotes to humans. ABC transporters belong to translocases. ABC transporters often consist of multiple subunits, one or two of which are transmembrane proteins and one or two of which are membrane-associated AAA ATPases. The ATPase subunits utilize the energy of adenosine triphosphate (ATP) binding and hydrolysis to provide the energy needed for the translocation of substrates across membranes, either for uptake or for export of the substrate. Most of the uptake systems also have an extracytoplasmic receptor, a solute binding protein. Some homologous ATPases function in non-transport-related processes such as translation of RNA and DNA repair. ABC transporters are considered to be an ABC superfamily based on the similarities of the sequence and organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colchicine
Colchicine is a medication used to prevent and treat gout, to treat familial Mediterranean fever and Behçet's disease, and to reduce the risk of myocardial infarction. The American College of Rheumatology recommends colchicine, nonsteroidal anti-inflammatory drugs (NSAIDs) or steroids in the treatment of gout. Other uses for colchicine include the management of pericarditis. Colchicine is taken by mouth. The injectable route of administration for colchicine can be toxic. In 2008, the US Food and Drug Administration removed all injectable colchicine from the US market. Colchicine has a narrow therapeutic index, so overdosing is a significant risk. Common side effects of colchicine include gastrointestinal upset, particularly at high doses. Severe side effects may include pancytopenia (low blood cell counts) and rhabdomyolysis (damage to skeletal muscle), and the medication can be deadly in overdose. Whether colchicine is safe for use during pregnancy is unclear, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antineoplastic Resistance
Antineoplastic resistance, often used interchangeably with chemotherapy resistance, is the resistance of neoplastic (cancerous) cells, or the ability of cancer cells to survive and grow despite anti-cancer therapies. In some cases, cancers can evolve resistance to multiple drugs, called multiple drug resistance. There are two general causes of antineoplastic therapy failure: Inherent genetic characteristics, giving cancer cells their resistance and acquired resistance after drug exposure, which is rooted in the concept of cancer cell heterogeneity. Characteristics of resistant cells include altered membrane transport, enhanced DNA repair, apoptotic pathway defects, alteration of target molecules, protein and pathway mechanisms, such as enzymatic deactivation. Since cancer is a genetic disease, two genomic events underlie acquired drug resistance: Genome alterations (e.g. gene amplification and deletion) and epigenetic modifications. Cancer cells are constantly using a variety of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycoprotein
Glycoproteins are proteins which contain oligosaccharide (sugar) chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated. In proteins that have segments extending extracellularly, the extracellular segments are also often glycosylated. Glycoproteins are also often important integral membrane proteins, where they play a role in cell–cell interactions. It is important to distinguish endoplasmic reticulum-based glycosylation of the secretory system from reversible cytosolic-nuclear glycosylation. Glycoproteins of the cytosol and nucleus can be modified through the reversible addition of a single GlcNAc residue that is considered reciprocal to phosphorylation and the functions of these are likely to be an additional regulatory mechanism that controls phosphorylation-based signalling. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Efflux Pump
An efflux pump is an active transporter in cells that moves out unwanted material. Efflux pumps are an important component in bacteria, particularly in their ability to remove antibiotics. The efflux process can also involve the movement of heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals, bacterial metabolites, and neurotransmitters. All microorganisms, with a few exceptions, have highly conserved DNA sequences in their genome that encode efflux pumps. Efflux pumps actively move substances out of a microorganism, in a process known as active efflux, which is a vital part of xenobiotic metabolism. This active efflux mechanism is responsible for various types of resistance to bacterial pathogens within bacterial species, the most concerning being antibiotic resistance, as microorganisms can have adapted efflux pumps to divert toxins out of the cytoplasm and into extracellular media. Efflux systems function via an energy-dependent mechanism (activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood–brain Barrier
The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system, thus protecting the brain from harmful or unwanted substances in the blood. The blood–brain barrier is formed by endothelial cells of the Capillary, capillary wall, astrocyte end-feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane. This system allows the passage of some small molecules by passive transport, passive diffusion, as well as the selective and active transport of various nutrients, ions, organic anions, and macromolecules such as glucose and amino acids that are crucial to neural function. The blood–brain barrier restricts the passage of pathogens, the diffusion of solutes in the blood, and Molecular mass, large or Hydrophile, hydrophilic molecules into the cerebrospinal fluid, while a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victor Ling
Victor Ling, (; born 1943) is a Canadian researcher in the field of medicine. Ling's research focuses on drug resistance in cancer. He is best known for his discovery of P-glycoprotein, one of the proteins responsible for multidrug resistance. Early life Ling was born in Shanghai, China in 1943, and is of Teochew ancestry. He moved to Hong Kong with his family in 1949 and lived there until 1952, when they emigrated to Canada. He graduated from North Toronto Collegiate in 1962. He received his bachelor's degree in 1966 from the University of Toronto and his PhD in 1969 from the University of British Columbia. Career Ling undertook post-doctoral training with Nobel laureate Fred Sanger at Cambridge University before returning to Toronto. He is currently Assistant Dean of the Faculty of Medicine at the University of British Columbia and former vice-president, Discovery at the BC Cancer Agency in Vancouver, British Columbia, as well as the President and Scientific Director of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multidrug Resistance
Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories are classifications of antimicrobial agents based on their mode of action and specific to target organisms. The MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, parasitism, parasites (resistant to multiple antifungal, antiviral drug, antiviral, and antiparasitic drugs of a wide chemical variety). Recognizing different degrees of MDR in bacteria, the terms ''extensively drug-resistant'' (''XDR'') and ''pandrug-resistant'' (''PDR'') have been introduced. ''Extensively drug-resistant (XDR)'' is the non-susceptibility of one bacteria species to all antimicrobial agents except in two or less antimicrobial categories. Within XDR, ''pandrug-resistant (PDR)'' is the non-sus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid Bilayer
The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes form a continuous barrier around all cell (biology), cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear envelope, nuclear membrane surrounding the cell nucleus, and biological membrane, membranes of the membrane-bound organelles in the cell. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be. Lipid bilayers are ideally suited to this role, even though they are only a few nanometers in width, because they are impermeable to most water-soluble (hydrophilic) molecules. Bilayers are particularly impermeable to ions, which allows cells to regulate salt concentrations and pH by transporting ions across their membranes using proteins called Ion transporter, ion pumps. Biological bilaye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multidrug Resistance
Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories are classifications of antimicrobial agents based on their mode of action and specific to target organisms. The MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, parasitism, parasites (resistant to multiple antifungal, antiviral drug, antiviral, and antiparasitic drugs of a wide chemical variety). Recognizing different degrees of MDR in bacteria, the terms ''extensively drug-resistant'' (''XDR'') and ''pandrug-resistant'' (''PDR'') have been introduced. ''Extensively drug-resistant (XDR)'' is the non-susceptibility of one bacteria species to all antimicrobial agents except in two or less antimicrobial categories. Within XDR, ''pandrug-resistant (PDR)'' is the non-sus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothelium
The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Endothelial cells in direct contact with blood are called vascular endothelial cells whereas those in direct contact with lymph are known as lymphatic endothelial cells. Vascular endothelial cells line the entire circulatory system, from the heart to the smallest capillaries. These cells have unique functions that include fluid filtration, such as in the glomerulus of the kidney, blood vessel tone, hemostasis, neutrophil recruitment, and hormone trafficking. Endothelium of the interior surfaces of the heart chambers is called endocardium. An impaired function can lead to serious health issues throughout the body. Structure The endothelium is a thin layer of single flat (squamous) cells that line the inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
