25,729 articles
Oligoarticular juvenile idiopathic arthritis
Oligoarticular juvenile idiopathic arthritis is the most common chronic arthritis of childhood in Europe and North America, typically affecting a knee or ankle in girls under six.
Oligoastrocytoma, dual genotype
Oligoastrocytoma, dual genotype (ORPHA:251656), also called mixed oligoastrocytoma, is a rare low-grade mixed glioma containing both astrocytoma-type (TP53/ATRX) and oligodendroglioma-type (1p/19q codeleted) genotypes; fewer than 10 cases reported, term deleted in WHO 2021.
Oligocone trichromacy
Oligocone trichromacy (oligocone syndrome, ORPHA:75378) is a rare congenital cone dysfunction disorder with reduced visual acuity, absent or reduced cone ERG, normal fundus and rod responses, and preserved color vision; some cases involve CNGA3, CNGB3, or PDE6C mutations.
Oligodendrocyte
Oligodendrocyte, also called oligodendroglia: CNS glial cell forming myelin sheaths around multiple axons (up to 1–40), unlike single-axon Schwann cells; arises from OPCs, supports axons metabolically, and enables remyelination in multiple sclerosis.
Oligodendrocyte precursor cell
Oligodendrocyte precursor cells (OPCs), also called NG2 glia or polydendrocytes, are CNS glia that generate myelinating oligodendrocytes, receive synaptic input, remodel synapses, support the blood-brain barrier, and drive remyelination in multiple sclerosis.
Oligodendroglioma
Oligodendroglioma, also known as an oligodendroglial tumor, is a brain tumor defined by an IDH mutation and 1p/19q codeletion, most common between ages 35 and 44 and often first causing seizures.
Oligodendroglioma grade 3
Oligodendroglioma grade 3 (formerly anaplastic oligodendroglioma) is a malignant IDH-mutant, 1p/19q-codeleted brain tumor; standard care is radiotherapy plus PCV chemotherapy, with temozolomide as a toxicity-sparing alternative.
Oligodontia
Oligodontia, or selective tooth agenesis, is the congenital absence of six or more permanent teeth excluding third molars. Prevalence 1/625–1/1,250 in Europeans; caused by WNT10A, PAX9, and other genes, isolated or syndromic.
Oligohydramnios
Oligohydramnios, low amniotic fluid volume in pregnancy, is diagnosed as AFI ≤5 cm or single deepest pocket <2 cm; causes include membrane rupture, placental insufficiency, and fetal urinary anomalies.
Oligomeganephronia
Oligomeganephronia (oligomeganephronic renal hypoplasia) is a rare congenital kidney malformation with about 80% fewer nephrons and marked glomerular and tubular hypertrophy, causing childhood or adolescent renal failure, sometimes with PAX2 or chromosomal syndromes.
Oliguria
Oliguria, also called low urine output, is urine production below 500 mL/24h or 0.5 mL/kg/hour. It is a KDIGO criterion for acute kidney injury staging, with prerenal, renal, and postrenal causes.
OLIMPAS study
OLIMPAS (Osseointegrated Limb Implant Microbiome Population Adaptation Study), NCT06310239, is a recruiting observational study at Walter Reed tracking skin microbiome changes after osseointegration surgery in 50 amputees across eight timepoints, linking microbial species to wound healing rates.
Olipudase alfa
Olipudase alfa (Xenpozyme, olipudase alfa-rpcp) is Sanofi's recombinant human acid sphingomyelinase enzyme replacement therapy, first approved in 2022, treating non-CNS manifestations of acid sphingomyelinase deficiency (Niemann-Pick A/B and B) at 3 mg/kg every 2 weeks.
Olive leaf extract
Olive leaf extract, from Olea europaea leaves, is a polyphenol-rich supplement and food ingredient standardized to oleuropein and hydroxytyrosol; FDA issued a no-questions GRAS letter (GRN 1119) in 2024.
Oliver Sacks
Oliver Sacks (1933–2015), British-born neurologist and author in New York, wrote Awakenings and The Man Who Mistook His Wife for a Hat; known for narrative case histories, L-dopa work at Beth Abraham, and later accuracy controversies.
Olivocochlear system
Olivocochlear system: brainstem-to-cochlea efferent pathway from the superior olivary complex, divided into medial (MOC, outer hair cells, cholinergic gain reduction) and lateral (LOC) divisions, studied via otoacoustic emissions for protection and speech-in-noise roles.
Ollier disease
Ollier disease (enchondromatosis, dyschondroplasia) is a rare bone dysplasia with multiple asymmetric enchondromas caused by somatic IDH1/IDH2 mutations, with elevated chondrosarcoma risk.
Olmesartan
Olmesartan (Benicar) is an angiotensin II receptor blocker prodrug (olmesartan medoxomil) approved in the US in 2002 for hypertension; known for 24-hour BP lowering, sprue-like enteropathy risk, and ROADMAP and SUPPORT trial findings.
Olmutinib
Olmutinib (BI 1482694, HM61713, brand Olita) is an oral, irreversible, mutant-selective third-generation EGFR tyrosine kinase inhibitor for T790M-positive NSCLC, approved in South Korea in 2016 but discontinued after fatal skin toxicity and inferior results versus osimertinib.
Olodaterol
Olodaterol (Striverdi Respimat) is a once-daily long-acting beta2-agonist inhalation bronchodilator by Boehringer Ingelheim for COPD maintenance, 5 µg via Respimat; also combined with tiotropium as Stiolto/Spiolto Respimat; not indicated for asthma.
Olokizumab
Olokizumab (OKZ, CDP6038), a humanized anti-IL-6 monoclonal antibody blocking the gp130 Site 3 epitope, developed by UCB Pharma and R-Pharm, approved in Russia for rheumatoid arthritis.
Olomorasib
Olomorasib (LY3537982), Eli Lilly/Loxo's second-generation covalent KRAS G12C inhibitor, differs from approved sotorasib and adagrasib by nanomolar potency, >90% target occupancy, activity against second-site resistance mutations, and phase 3 SUNRAY trials.
Olopatadine
Olopatadine (KW-4679, AL-4943A), a doxepin analog, is a topical H1 antihistamine and mast cell stabilizer used as eye drops and nasal spray for allergic conjunctivitis and rhinitis; first FDA-approved 1996.
Olorigliflozin
Olorigliflozin (奥洛格列净), brand Dongze'an, is Sunshine Lake Pharma's Class 1 SGLT2 inhibitor capsule (20/50 mg) approved by China's NMPA in January 2026 for type 2 diabetes, alone or with metformin.
Olorofim
Olorofim (F901318), first-in-class orotomide antifungal from F2G, inhibits fungal DHODH in pyrimidine synthesis; active against azole-resistant Aspergillus, Lomentospora, Scedosporium, Coccidioides, inactive against yeasts and Mucorales; oral, phase 2b/3 studied.
Olsalazine
Olsalazine (Dipentum) is an azo-bonded 5-ASA dimer prodrug, US-approved 1987, for maintaining ulcerative colitis remission in sulfasalazine-intolerant adults; 500 mg twice daily, with secretory diarrhea as its distinguishing adverse effect.
Oltipraz
Oltipraz (RP 35972), a synthetic dithiolethione once marketed by Rhone-Poulenc for schistosomiasis, is an Nrf2-activating Phase II enzyme inducer studied as a cancer chemopreventive and NAFLD drug.
Olumacostat glasaretil
Olumacostat glasaretil (formerly DRM01) is a topical acetyl-CoA carboxylase inhibitor pro-drug developed by Dermira to cut sebum in acne; Phase 3 trials CLAREOS-1 and CLAREOS-2 missed endpoints in 2018 and development was discontinued.
Olutasidenib
Olutasidenib (Rezlidhia) is an oral mutant IDH1 inhibitor approved by the FDA in December 2022 for relapsed or refractory AML with a susceptible IDH1 mutation, dosed 150 mg twice daily, with 35% CR+CRh and a boxed warning for differentiation syndrome.
Olverembatinib
Olverembatinib (奥雷巴替尼, Henglike, HQP1351, formerly GZD824) is an oral third-generation BCR-ABL1 tyrosine kinase inhibitor for T315I-mutated and TKI-resistant CML, approved in China since November 2021 and in global phase 3 development.