72,234 articles
Cyclic vomiting syndrome
Cyclic vomiting syndrome (CVS), a functional gut-brain disorder with recurrent stereotypical vomiting episodes separated by symptom-free intervals; key differential is cannabinoid hyperemesis syndrome; migraine-linked, treated with tricyclics and antiemetics.
Cyclida
Cyclida (cyclidans, "sea ticks") is an extinct order of Multicrustacea crustaceans with a rounded carapace covering the body, known from the Early Carboniferous to Late Cretaceous, with 52 reviewed species in six families from marine, brackish, and freshwater habitats.
Cyclin
Cyclins: regulatory proteins with a cyclin box domain that bind and activate cyclin-dependent kinases (CDKs) to drive the cell cycle; canonical types D, E, A, B; Tim Hunt shared the 2001 Nobel Prize; cyclin D–CDK4/6 inhibitors treat breast cancer.
Cyclin P/U
Cyclin P/U (InterPro IPR012389, Negative regulatory factor PREG) is a cyclin-like protein family of P-type cyclins regulating CDKs; found in plants and yeast Pho80, absent from animals, linked to nutritional sensing and cell cycle control.
Cyclin-dependent kinase
Cyclin-dependent kinases (CDKs, CDK1–CDK20) are cyclin-dependent serine/threonine kinases regulating the eukaryotic cell cycle and transcription; discovered via yeast cdc2/CDC28 genetics, honored by the 2001 Nobel Prize, and targeted by approved CDK4/6 cancer drugs.
Cyclin-dependent kinase 6
CDK6 (cyclin-dependent kinase 6, aliases PLSTIRE, MCPH12) is a human serine/threonine kinase on 7q21.2 that, with D-type cyclins, drives G1/S cell-cycle transition via Rb phosphorylation, has kinase-independent transcriptional roles, and is targeted by CDK4/6 inhibitors in breast cancer.
Cyclin-dependent kinase 7
Cyclin-dependent kinase 7 (CDK7), with cyclin H and MAT1, forms CAK activating CDKs 1/2/4/6 and is a TFIIH kinase phosphorylating Pol II CTD Ser5/Ser7; targeted by covalent inhibitors THZ1 and YKL-5-124 and clinical candidates ICEC0942, SY-1365, SY-5609, LY3405105.
Cyclin-dependent kinase inhibitor
Cyclin-dependent kinase inhibitors, also called CDK inhibitors or CKIs, include endogenous proteins p21, p27, and p16 and small-molecule anticancer drugs; palbociclib was the first FDA-approved CDK4/6 inhibitor for breast cancer.
Cyclizine
Cyclizine (Marezine, Valoid) is a piperazine H1 antihistamine antiemetic developed by Burroughs Wellcome in 1947, used for motion sickness, vertigo, and PONV, and carried on Apollo missions for space sickness.
Cycloartenol synthase
Cycloartenol synthase (CAS1, EC 5.4.99.8) is the plant oxidosqualene cyclase making cycloartenol, the first sterol of the plant pathway, distinct from animal and fungal lanosterol synthase; first cloned from Arabidopsis in 1993.
Cycloate
Cycloate (Ro-Neet, CAS 1134-23-2) is a thiocarbamate pre-emergent herbicide used mainly on sugar beets, spinach, and garden beets; first US-registered 1967, not EU-approved, an acetylcholinesterase-inhibiting thiocarbamate.
Cyclobarbital
Cyclobarbital (cyclobarbitone, Phanodorm, Cyclodorm) is a rapid, short-acting barbiturate hypnotic, 5-(1-cyclohexen-1-yl)-5-ethylbarbituric acid, ATC N05CA10, WHO DDD 0.2 g oral, UN Schedule III.
Cyclobenzaprine
Cyclobenzaprine (Flexeril) is a tricyclic, centrally acting skeletal muscle relaxant, structurally related to amitriptyline, approved in 1977 for short-term relief of acute musculoskeletal muscle spasm, ineffective for spasticity.
Cyclodextrin nanoparticles
Cyclodextrin nanoparticles are drug-delivery particles in which cyclodextrins, cyclic sugars with hydrophobic cavities, improve the solubility, stability, and targeting of drugs, most notably in cancer therapy.
Cyclofenil
Cyclofenil (Ondogyne, Fertodur, F-6066) is a non-steroidal ovulation inducer related to clomiphene, once used for female infertility and amenorrhea, now a WADA-prohibited anti-estrogen.
Cycloheximide
Cycloheximide (also known as Actidione or CHX) is a glutarimide antibiotic isolated from Streptomyces griseus that inhibits protein synthesis in eukaryotic cells by blocking translation.
Cyclooxygenase
Cyclooxygenase (COX, prostaglandin endoperoxide H synthase) is the enzyme converting arachidonic acid to prostaglandins and thromboxanes; two isoforms, COX-1 and COX-2, are the targets of NSAIDs such as aspirin and ibuprofen.
Cyclooxygenase-2 inhibitor
Cyclooxygenase-2 (COX-2) inhibitors, or coxibs (celecoxib, rofecoxib, etoricoxib), are NSAIDs selectively blocking the COX-2 enzyme to treat arthritis pain with less gastrointestinal toxicity, but carry cardiovascular, renal, and blood pressure risks; rofecoxib and valdecoxib were withdrawn in 2004–2005.
Cyclopamine
Cyclopamine, also known as 11-deoxojervine, is a steroidal alkaloid from the California corn lily that causes one-eyed lambs and, by binding Smoothened, became the template for Hedgehog pathway cancer drugs.
Cyclopentolate
Cyclopentolate (Cyclogyl) is a synthetic antimuscarinic eye drop producing mydriasis and cycloplegia for diagnostic refraction; onset 15-60 min, recovery within 24 h, WHO essential medicine, first approved 1974.
Cyclopes (animal)
Cyclopes, the pygmy or silky anteaters, is the sole living genus of family Cyclopedidae, small arboreal insectivorous mammals from southern Mexico to South America, redefined in 2017 as seven species.
Cyclophilin-RNA interacting protein
Cyclophilin-RNA interacting proteins (CRIPs) are a conserved family of nuclear proteins combining a cyclophilin isomerase domain with an RNA recognition motif, named from the Paramecium protein KIN241.
Cyclophosphamide
Cyclophosphamide (Endoxan, Cytoxan) is a nitrogen mustard-derived alkylating chemotherapy prodrug, FDA-approved in 1959, used for leukemias, lymphomas, breast and ovarian cancer, autoimmune disease, and transplant conditioning.
Cyclophosphamide/dexamethasone regimen
The cyclophosphamide/dexamethasone (Cy-Dex) regimen is a chemotherapy combination pairing the alkylating agent cyclophosphamide with the corticosteroid dexamethasone, formerly used as induction therapy for multiple myeloma before stem cell transplantation.
Cyclophosphamide/doxorubicin regimen (chemotherapy)
The cyclophosphamide/doxorubicin regimen, usually abbreviated AC or CA, is a two-drug chemotherapy combination pairing the alkylator cyclophosphamide with the anthracycline doxorubicin, used mainly to treat operable breast cancer.
Cyclopia
Cyclopia (synophthalmia) is the most severe facial form of holoprosencephaly: a single central eye with absent nose or proboscis, caused by failed forebrain division; prevalence 1 in 100,000 births, lethal within days, linked to SHH mutations, trisomy 13, and cyclopamine.
Cyclopiazonic acid (α-CPA)
Cyclopiazonic acid (α-CPA, alpha-cyclopiazonic acid) is an indole-tetramic acid mycotoxin from Aspergillus and Penicillium molds, first isolated in 1968, that inhibits SERCA calcium pumps at nanomolar concentrations.
Cyclopoida
Cyclopoida (Burmeister, 1834/1835) is a major order of copepod crustaceans, one of the three largest alongside Calanoida and Harpacticoida, with over 800 freshwater species, short antennae, benthic and planktonic habits, six parasitic families, and Mesocyclops used against mosquito larvae.
Cyclopterus lumpus
Cyclopterus lumpus, the lumpfish or lumpsucker, a North Atlantic ball-shaped fish fished for caviar-substitute roe and used as cleaner fish against sea lice; IUCN Near Threatened, Threatened in Canada, Danish fishery closed 2025.
Cyclosa turbinata
Cyclosa turbinata, the humped trashline orbweaver (Araneidae), is a small American orb-weaving spider from the USA to Panama, introduced to Hawaii, that hides on a debris-lined trashline in its orb web and shows diurnal thanatosis and nocturnal foraging.