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Hepatitis D
Hepatitis D is a type of viral hepatitis caused by the hepatitis delta virus (HDV). HDV is one of five known hepatitis viruses: A, B, C, D, and E. HDV is considered to be a satellite (a type of subviral agent) because it can propagate only in the presence of the hepatitis B virus (HBV). Transmission of HDV can occur either via simultaneous infection with HBV (coinfection) or superimposed on chronic hepatitis B or hepatitis B carrier state (superinfection). HDV infecting a person with chronic hepatitis B (superinfection) is considered the most serious type of viral hepatitis due to its severity of complications. These complications include a greater likelihood of experiencing liver failure in acute infections and a rapid progression to liver cirrhosis, with an increased risk of developing liver cancer in chronic infections. In combination with hepatitis B virus, hepatitis D has the highest fatality rate of all the hepatitis infections, at 20%. A recent estimate from 2020 suggest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastroenterology
Gastroenterology (from the Greek gastḗr- “belly”, -énteron “intestine”, and -logía "study of") is the branch of medicine focused on the digestive system and its disorders. The digestive system consists of the gastrointestinal tract, sometimes referred to as the ''GI tract,'' which includes the esophagus, stomach, small intestine and large intestine as well as the accessory organs of digestion which includes the pancreas, gallbladder, and liver. The digestive system functions to move material through the GI tract via peristalsis, break down that material via digestion, absorb nutrients for use throughout the body, and remove waste from the body via defecation. Physicians who specialize in the medical specialty of gastroenterology are called gastroenterologists or sometimes ''GI doctors''. Some of the most common conditions managed by gastroenterologists include gastroesophageal reflux disease, gastrointestinal bleeding, irritable bowel syndrome, irritable bow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribozyviria
''Ribozyviria'' is a realm of satellite nucleic acids. Established in ICTV TaxoProp 2020.012D, the realm is named after the presence of genomic and antigenomic ribozymes of the ''Deltavirus'' type. Additional common features include a rod-like structure, a RNA-binding "delta antigen" encoded in the genome, and animal hosts. Furthermore, the size range of the genomes of these viruses is between around 1547–1735nt, they encode a hammerhead ribozyme or a hepatitis delta virus ribozyme, and their coding capacity only involves one conserved protein. Most lineages of this realm are poorly understood, the notable exception being members of the genus ''Deltavirus'', the causal agents of Hepatitis D in humans. This realm of viruses have an unclear origin. They may have derived from retrozymes (a family of retrotransposons) or one of the other groups of mobile genetic elements that descended from retrozymes (i.e. viroids and satellites). But it was also proposed that they may have orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drug Injection
Drug injection is a method of introducing a drug into the bloodstream via a hollow hypodermic needle, which is pierced through the skin into the body (usually intravenously, but also at an intramuscular or subcutaneous location). Intravenous therapy, a form of drug injection, is universally practiced in modernized medical care. , there were 13.2 million people worldwide who self-administered injection drugs outside of medical supervision, of which 22% are from developed countries. A wide variety of drugs are injected, often opioids: these may include legally prescribed medicines and medication such as morphine, as well as stronger compounds often favored in recreational drug use, which are often illegal. Although there are various methods of taking drugs, injection is favoured by some people as the full effects of the drug are experienced very quickly, typically in five to ten seconds. It also bypasses first-pass metabolism in the liver, resulting in higher bioavailability an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developed Country
A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastructure relative to other less industrialized nations. Most commonly, the criteria for evaluating the degree of economic development are gross domestic product (GDP), gross national product (GNP), the per capita income, level of industrialization, amount of widespread infrastructure and general standard of living. Which criteria are to be used and which countries can be classified as being developed are subjects of debate. A point of reference of US$20,000 in 2021 USD nominal GDP per capita for the International Monetary Fund (IMF) is a good point of departure, it is a similar level of development to the United States in 1960. Developed countries have generally more advanced post-industrial economies, meaning the service sector provides mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribozyme
Ribozymes (ribonucleic acid enzymes) are RNA molecules that have the ability to catalyze specific biochemical reactions, including RNA splicing in gene expression, similar to the action of protein enzymes. The 1982 discovery of ribozymes demonstrated that RNA can be both genetic material (like DNA) and a biological catalyst (like protein enzymes), and contributed to the RNA world hypothesis, which suggests that RNA may have been important in the evolution of prebiotic self-replicating systems. The most common activities of natural or in vitro-evolved ribozymes are the cleavage or ligation of RNA and DNA and peptide bond formation. For example, the smallest ribozyme known (GUGGC-3') can aminoacylate a GCCU-3' sequence in the presence of PheAMP. Within the ribosome, ribozymes function as part of the large subunit ribosomal RNA to link amino acids during protein synthesis. They also participate in a variety of RNA processing reactions, including RNA splicing, viral replication, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis Delta Virus Ribozyme
The hepatitis delta virus (HDV) ribozyme is a non-coding RNA found in the hepatitis delta virus that is necessary for viral replication and is the only known human virus that utilizes ribozyme activity to infect its host. The ribozyme acts to process the RNA transcripts to unit lengths in a self-cleavage reaction during replication of the hepatitis delta virus, which is thought to propagate by a double rolling circle mechanism. The ribozyme is active ''in vivo'' in the absence of any protein factors and was the fastest known naturally occurring self-cleaving RNA at the time of its discovery. The crystal structure of this ribozyme has been solved using X-ray crystallography and shows five helical segments connected by a double pseudoknot. In addition to the sense (genomic version), all HDV viruses also have an antigenomic version of the HDV ribozyme. This version is not the exact complementary sequence but adopts the same structure as the sense (genomic) strand. The only "signif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigenome
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RNA Polymerase
In molecular biology, RNA polymerase (abbreviated RNAP or RNApol), or more specifically DNA-directed/dependent RNA polymerase (DdRP), is an enzyme that synthesizes RNA from a DNA template. Using the enzyme helicase, RNAP locally opens the double-stranded DNA so that one strand of the exposed nucleotides can be used as a template for the synthesis of RNA, a process called transcription. A transcription factor and its associated transcription mediator complex must be attached to a DNA binding site called a promoter region before RNAP can initiate the DNA unwinding at that position. RNAP not only initiates RNA transcription, it also guides the nucleotides into position, facilitates attachment and elongation, has intrinsic proofreading and replacement capabilities, and termination recognition capability. In eukaryotes, RNAP can build chains as long as 2.4 million nucleotides. RNAP produces RNA that, functionally, is either for protein coding, i.e. messenger RNA (mRNA); o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HBsAg
HBsAg (also known as the Australia antigen) is the surface antigen of the hepatitis B virus (HBV). Its presence in blood indicates current hepatitis B infection. Structure and function The viral envelope of an enveloped virus has different surface proteins from the rest of the virus which act as antigens. These antigens are recognized by antibody proteins that bind specifically to one of these surface proteins. Immunoassay Today, these antigen-proteins can be genetically manufactured (e.g. transgene '' E. coli'') to produce material for a simple antigen test, which detects the presence of HBV. It is present in the sera of patients with viral hepatitis B (with or without clinical symptoms). Patients who developed antibodies against HBsAg (anti-HBsAg seroconversion) are usually considered non-infectious. HBsAg detection by immunoassay is used in blood screening, to establish a diagnosis of hepatitis B infection in the clinical setting (in combination with other disease markers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLC10A1
Sodium/bile acid cotransporter also known as the Na+-taurocholate cotransporting polypeptide (NTCP) or liver bile acid transporter (LBAT) is a protein that in humans is encoded by the ''SLC10A1'' (solute carrier family 10 member 1) gene. Structure Sodium/bile acid cotransporters are integral membrane glycoproteins. Human NTCP contains 349 amino acids and has a mass of 56 kDa. Function Bile acid:sodium symporters participate in the enterohepatic circulation of bile acids. Two homologous transporters are involved in the reabsorption of bile acids. One of these absorbs bile acids from the intestinal lumen, the bile duct, and the kidney with an apical localization ( ileal sodium/bile acid cotransporter). The other is this protein and is expressed in the basolateral membranes of hepatocytes (NTCP). As a cotransporter, NTCP binds two sodium ions and one (conjugated) bile salt molecule, thereby providing a hepatic influx of bile salts. Other transported molecules include ster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viroids
Viroids are small single-stranded, circular RNAs that are infectious pathogens. Unlike viruses, they have no protein coating. All known viroids are inhabitants of angiosperms (flowering plants), and most cause diseases, whose respective economic importance to humans varies widely. The first discoveries of viroids in the 1970s triggered the historically third major extension of the biosphere—to include smaller lifelike entities —after the discoveries in 1675 by Antonie van Leeuwenhoek (of the "subvisible" microorganisms) and in 1892–1898 by Dmitri Iosifovich Ivanovsky and Martinus Beijerinck (of the "submicroscopic" viruses). The unique properties of viroids have been recognized by the International Committee on Taxonomy of Viruses, in creating a new order of subviral agents. The first recognized viroid, the pathogenic agent of the potato spindle tuber disease, was discovered, initially molecularly characterized, and named by Theodor Otto Diener, plant pathologist at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circular RNA
Circular RNA (or circRNA) is a type of single-stranded RNA which, unlike linear RNA, forms a covalently closed continuous loop. In circular RNA, the 3' and 5' ends normally present in an RNA molecule have been joined together. This feature confers numerous properties to circular RNA, many of which have only recently been identified. Many types of circular RNA arise from otherwise protein-coding genes. Some circular RNA has been shown to code for proteins. Some types of circular RNA have also recently shown potential as gene regulators. The biological function of most circular RNA is unclear. Because circular RNA does not have 5' or 3' ends, it is resistant to exonuclease-mediated degradation and is presumably more stable than most linear RNA in cells. Circular RNA has been linked to some diseases such as cancer. RNA splicing In contrast to genes in bacteria, eukaryotic genes are split by non-coding sequences called introns. In eukaryotes, as a gene is transcribed from DNA i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
