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Brivudine
Brivudine (trade names Zostex, Mevir, Brivir, among others) is an antiviral drug used in the treatment of herpes zoster ("shingles"). Like other antivirals, it acts by inhibiting replication of the target virus. Medical uses Brivudine is used for the treatment of herpes zoster in adult patients. It is taken orally once daily, in contrast to aciclovir, valaciclovir and other antivirals. A study has found that it is more effective than aciclovir, but this has been disputed because of a possible conflict of interest on part of the study authors. Contraindications The drug is contraindicated in patients undergoing immunosuppression (for example because of an organ transplant) or cancer therapy, especially with fluorouracil (5-FU) and chemically related (pro)drugs such as capecitabine and tegafur, as well as the antimycotic drug flucytosine, which is also related to 5-FU. It has not been proven to be safe in children and pregnant or breastfeeding women. Adverse effects The drug is g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capecitabine
Capecitabine, sold under the brand name Xeloda among others, is a chemotherapy medication used to treat breast cancer, gastric cancer and colorectal cancer. For breast cancer it is often used together with docetaxel. It is taken by mouth. Common side effects include abdominal pain, vomiting, diarrhea, weakness, and rashes. Other severe side effects include blood clotting problems, allergic reactions, heart problems such as cardiomyopathy, and low blood cell counts. It is not recommended in people with kidney problems. Use during pregnancy may result in harm to the fetus. Capecitabine, inside the body, is converted to 5-fluorouracil (5-FU) through which it acts. It belongs to the class of medications known as fluoropyrimidines, which also includes 5-FU and tegafur. Capecitabine was patented in 1992 and approved for medical use in 1998. It is on the World Health Organization's List of Essential Medicines. Medical uses It is used in the treatment of the following cancers: * Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorivudine
Sorivudine (INN), is a nucleoside analogue antiviral drug, marketed under trade names such as Usevir ( Nippon Shoji, Eisai) and Brovavir (BMS). It is used for the treatment of varicella zoster virus infections. Pharmacology Feature * First-line treatment of herpes drug acyclovir was (Zovirax, Activir) from VZV strong activity of the virus. * Undergoes gastrointestinal absorption, absorption from the gastrointestinal tract after the most degrading without being excreted in urine. Mechanism of action * Sorivudine is phosphorylated by thymidine kinase activity in the body and is absorbed into the virus's DNA instead of the correct nucleoside. It is a competitive inhibitor of DNA polymerase, so the viral DNA cannot be replicated and the virus cannot grow. Microbiology Sorivudine is active against most species in the herpesvirus family. * Herpes simplex virus type I (HSV-1) * Varicella zoster virus (VZV) * Epstein–Barr virus (EBV) Interactions Sorivudine interacts strongly an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aciclovir
Aciclovir (ACV), also known as acyclovir, is an antiviral medication. It is primarily used for the treatment of herpes simplex virus infections, chickenpox, and shingles. Other uses include prevention of cytomegalovirus infections following transplant and severe complications of Epstein–Barr virus infection. It can be taken by mouth, applied as a cream, or injected. Common side effects include nausea and diarrhea. Potentially serious side effects include kidney problems and low platelets. Greater care is recommended in those with poor liver or kidney function. It is generally considered safe for use in pregnancy with no harm having been observed. It appears to be safe during breastfeeding. Aciclovir is a nucleoside analogue that mimics guanosine. It works by decreasing the production of the virus's DNA. Aciclovir was patented in 1974, and approved for medical use in 1981. It is on the World Health Organization's List of Essential Medicines. It is available as a generic me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymidine Phosphorylase
Thymidine phosphorylase () is an enzyme that is encoded by the TYMP (gene), TYMP gene and catalyzes the reaction: :thymidine + phosphate \rightleftharpoons thymine + 2-deoxy-alpha-D-ribose 1-phosphate Thymidine phosphorylase is involved in purine metabolism, pyrimidine metabolism, and other metabolism, metabolic pathways. Variations in thymidine phosphorylase and the ''TYMP'' gene that encode it are associated with Mitochondrial neurogastrointestinal encephalopathy syndrome, mitochondrial neurogastrointestinal encephalopathy (MNGIE) syndrome and bladder cancer. Nomenclature This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The List of enzymes, systematic name of this enzyme class is thymidine:phosphate deoxy-alpha-D-ribosyltransferase. Other names in common use include pyrimidine phosphorylase, thymidine-orthophosphate deoxyribosyltransferase, animal growth regulators, blood platelet-derived endothelial cell, growth factors, bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granulocytopenia
Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear. They have varying shapes (morphology) of the nucleus (segmented, irregular; often lobed into three segments); and are referred to as polymorphonuclear leukocytes (PMN, PML, or PMNL). In common terms, ''polymorphonuclear granulocyte'' refers specifically to "neutrophil granulocytes", the most abundant of the granulocytes; the other types (eosinophils, basophils, and mast cells) have varying morphology. Granulocytes are produced via granulopoiesis in the bone marrow. Types There are four types of granulocytes (full name polymorphonuclear granulocytes): * Basophils * Eosinophils * Neutrophils * Mast cells Except for the mast cells, their names are derived from their staining characteristics; for example, the most abundant granulocyte is the neutrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vitro
''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and its subdisciplines are traditionally done in labware such as test tubes, flasks, Petri dishes, and microtiter plates. Studies conducted using components of an organism that have been isolated from their usual biological surroundings permit a more detailed or more convenient analysis than can be done with whole organisms; however, results obtained from ''in vitro'' experiments may not fully or accurately predict the effects on a whole organism. In contrast to ''in vitro'' experiments, ''in vivo'' studies are those conducted in living organisms, including humans, and whole plants. Definition ''In vitro'' ( la, in glass; often not italicized in English usage) studies are conducted using components of an organism that have been isolated fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herpes Simplex Virus
Herpes simplex virus 1 and 2 (HSV-1 and HSV-2), also known by their taxonomical names ''Human alphaherpesvirus 1'' and '' Human alphaherpesvirus 2'', are two members of the human ''Herpesviridae'' family, a set of viruses that produce viral infections in the majority of humans. Both HSV-1 and HSV-2 are very common and contagious. They can be spread when an infected person begins shedding the virus. As of 2016, about 67% of the world population under the age of 50 had HSV-1. In the United States, about 47.8% and 11.9% are estimated to have HSV-1 and HSV-2, respectively, though actual prevalence may be much higher. Because it can be transmitted through any intimate contact, it is one of the most common sexually transmitted infections. Symptoms Many of those who are infected ''never'' develop symptoms. Symptoms, when they occur, may include watery blisters in the skin or mucous membranes of the mouth, lips, nose, genitals, or eyes (herpes simplex keratitis). Lesions heal with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varicella Zoster Virus
Varicella-zoster virus (VZV), also known as human herpesvirus 3 (HHV-3, HHV3) or ''Human alphaherpesvirus 3'' (taxonomically), is one of nine known herpes viruses that can infect humans. It causes chickenpox (varicella) commonly affecting children and young adults, and shingles (herpes zoster) in adults but rarely in children. VZV infections are species-specific to humans. The virus can survive in external environments for a few hours. VZV multiplies in the tonsils, and causes a wide variety of symptoms. Similar to the herpes simplex viruses, after primary infection with VZV (chickenpox), the virus lies dormant in neurons, including the cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia. Many years after the person has recovered from initial chickenpox infection, VZV can ''reactivate'' to cause shingles. Epidemiology Chickenpox Primary varicella zoster virus infection results in chickenpox (varicella), which may result in complications including encephaliti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Replication
Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm. Viral production / replication Viruses multiply only in living cells. The host cell must provide the energy and synthetic machinery and the low- molecular-weight precursors for the synthesis of viral proteins and nucleic acids. The virus replication occurs in seven stages, namely; # Attachment # Entry, # Uncoating, # Transcription / mRNA production, # Synthesis of virus components, # Virion assembly and # Release (Liberation Stage). Attachment It is the first step of viral replication ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome P450
Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance (pharmacology), clearance of various compounds, as well as for hormone synthesis and breakdown. In 1963, Ronald W. Estabrook, Estabrook, David Y. Cooper, Cooper, and Otto Rosenthal, Rosenthal described the role of CYP as a catalyst in steroid hormone synthesis and drug metabolism. In plants, these proteins are important for the biosynthesis of secondary metabolite, defensive compounds, fatty acids, and hormones. CYP enzymes have been identified in all kingdom (biology), kingdoms of life: animals, plants, fungus, fungi, protists, bacteria, and archaea, as well as in viruses. However, they are not omnipresent; for example, they have not been found in ''Escherichia coli''. , more than 300,000 distinct CYP proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropyrimidine Dehydrogenase
In enzymology, a dihydropyrimidine dehydrogenase (NADP+) () is an enzyme that catalyzes the chemical reaction :5,6-dihydrouracil + NADP+ \rightleftharpoons uracil + NADPH + H+ Thus, the two substrates of this enzyme are 5,6-dihydrouracil and NADP+, whereas its 3 products are uracil, NADPH, and H+. In humans the enzyme is encoded by the ''DPYD'' gene. It is the initial and rate-limiting step in pyrimidine catabolism. It catalyzes the reduction of uracil and thymine. It is also involved in the degradation of the chemotherapeutic drugs 5-fluorouracil and tegafur. It also participates in beta-alanine metabolism and pantothenate and coa biosynthesis. Terminology The systematic name of this enzyme class is 5,6-dihydrouracil:NADP+ 5-oxidoreductase. Other names in common use include: * dihydrothymine dehydrogenase *dihydrouracil dehydrogenase (NADP+) *4,5-dihydrothymine: oxidoreductase *DPD *DHPDH *dehydrogenase, dihydrouracil (nicotinamide adenine dinucleotide, phosphate) *DHU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolite
In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, catalytic activity of their own (usually as a cofactor to an enzyme), defense, and interactions with other organisms (e.g. pigments, odorants, and pheromones). A primary metabolite is directly involved in normal "growth", development, and reproduction. Ethylene exemplifies a primary metabolite produced large-scale by industrial microbiology. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments such as resins and terpenes etc. Some antibiotics use primary metabolites as precursors, such as actinomycin, which is created from the primary metabolite tryptophan. Some sugars are metabolites, such as fructose or glucose, which are both p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
