Human health and medicine

Oncologia

Oncologia, Latin for oncology, is the medical study of tumors. Greek-derived term attested from 1618, established by Virchow's cellular pathology; medical oncology became a subspecialty in 1972.

Oncologists are physicians specializing in cancer care, spanning medical oncology (drug therapy), radiation oncology (radiotherapy), and surgical oncology; training, roles, workforce numbers, and global access disparities.

Oncology

Oncology is the branch of medicine specializing in the diagnosis and treatment of cancer through medical, radiation, and surgical approaches, delivered by multidisciplinary teams; cancer is the second leading cause of death globally.

Oncology Nursing Society

Oncology Nursing Society (ONS), US professional association for cancer-care nurses, founded 1975, Pittsburgh HQ, 35,000+ members; affiliates ONCC (OCN certification) and Oncology Nursing Foundation; journals CJON and ONF.

Oncology research

Oncology Research (Oncol Res, ISSN 0965-0407) is a monthly peer-reviewed cancer research journal founded in 1992, absorbing Anti-Cancer Drug Design, published since 2021 open access by Tech Science Press, indexed in MEDLINE, 2025 impact factor 4.6.

Oncolytic virus therapy

Oncolytic virus therapy, also known as oncolytic virotherapy, is a cancer treatment using live engineered viruses to kill tumor cells and trigger immune responses, exemplified by T-VEC.

Oncoplastic breast surgery

Oncoplastic breast surgery, also called oncoplastic breast conserving surgery, combines wide tumor removal with immediate reshaping of the breast to keep clear margins and normal shape.

Oncorine (H101, recombinant human adenovirus type 5)

Oncorine (安柯瑞) is the trade name of H101, an oncolytic adenovirus developed by Shanghai Sunway Biotech and approved in China in 2005 for head and neck cancers.

Oncotic pressure

Oncotic pressure (colloid osmotic pressure) is the osmotic pull of plasma proteins, mainly albumin (up to 80%), across capillary walls; a Starling force revised by the endothelial glycocalyx model, central to edema and fluid therapy.

Onda 10

Onda 10 (no.10, CVCL_3075) is a human glioblastoma/anaplastic glioma cell line established by Onda et al. from the left parietal lobe of a 62-year-old Japanese man, TP53-mutant, GFAP-positive early on, distributed as JCRB IFO50368.

Ondansetron

Ondansetron (Zofran) is a selective 5-HT3 receptor antagonist antiemetic developed by Glaxo, FDA-approved January 1991 for chemotherapy-, radiotherapy-, and surgery-induced nausea and vomiting, with QT-prolongation limits.

One Health

One Health is an integrated approach that balances the linked health of people, animals, and ecosystems, addressing zoonotic diseases, antimicrobial resistance, and food safety through cross-sector collaboration.

One-lung ventilation

One-lung ventilation, also known as single-lung ventilation, is an anesthetic technique that mechanically separates the lungs so only one is ventilated, chiefly for thoracic surgery.

Onfekafusp alfa

Onfekafusp alfa (Fibromun, L19-TNF, L19TNF) is Philogen's investigational immunocytokine fusing human TNF-alpha to the L19 scFv targeting ED-B fibronectin on tumor vessels; studied in sarcoma, melanoma, and glioma, not yet authorized.

Ongericimab

Ongericimab (JS002, Junshida 君适达) is Shanghai Junshi Biosciences' subcutaneous anti-PCSK9 monoclonal antibody; NMPA approved it in 2025 for primary hypercholesterolemia and mixed dyslipidemia, lowering LDL-C about 55–70%.

Onlay mesh repair

Onlay mesh repair is a ventral hernia repair technique in which prosthetic mesh is placed over the closed abdominal wall fascia, reinforcing a tension-free primary closure.

Onradivir tablets

Onradivir tablets (昂拉地韦片, Anruiwei, ZSP1273) is a Chinese class 1 antiviral approved May 2025 for uncomplicated influenza A in adults; the first approved PB2 RNA polymerase inhibitor, dosed 0.6 g daily for 5 days.

Ontario Health

Ontario Health (Santé Ontario), agency created 2019 by the Government of Ontario to connect, coordinate and modernize health care; absorbed Cancer Care Ontario, Trillium Gift of Life Network and 14 LHINs; six regional teams, Ontario Health atHome subsidiary.

Oct 20, 2026

Ontario Ministry of Health

The Ontario Ministry of Health is the Ontario government department responsible for the province's publicly funded health-care system, managing OHIP, drug programs, and emergency health services.

Onychocytic matricoma

Onychocytic matricoma (acanthoma of the nail matrix) is a rare benign nail matrix tumor first described by Perrin in 2012, causing monodactylous longitudinal pachymelanonychia with nail plate thickening, purely epithelial histology, and mimicry of melanoma and onychocytic carcinoma.

Onycholysis

Onycholysis, also called nail plate separation or detachment, is a common nail disorder in which the nail plate lifts off the nail bed, appearing white and opaque. Causes include trauma, psoriasis, fungal infection, thyroid disease, and drugs such as tetracyclines and taxanes.

Onychomatricoma

Onychomatricoma is a rare benign fibroepithelial tumor of the nail matrix, first described by Baran and Kint in 1992, causing yellow thickened overcurved nails with splinter hemorrhages, woodworm-like cavities, and coexisting onychomycosis; treated by surgical excision.

Onychomycosis

Onychomycosis (tinea unguium, nail fungus): fungal infection of the nail, mainly Trichophyton rubrum, causing 2–13% population prevalence. Diagnosed by KOH, culture, PCR, PAS; treated with terbinafine, itraconazole, or efinaconazole.

Oocyte donation

Oocyte donation is a fertility treatment in which eggs from a donor are fertilized in vitro and transferred to a recipient, pioneered at Monash in 1984.

Oocyte retrieval

Oocyte retrieval, also called oocyte aspiration, is the medical procedure of collecting mature eggs from ovarian follicles for in vitro fertilization, standard since the late 1980s as transvaginal ultrasound-guided aspiration.

Oocyte vitrification

Oocyte vitrification is a cryopreservation method that cools human eggs so rapidly they solidify into a glass-like state without ice crystals, replacing slow freezing as the standard for fertility preservation.

Oophorectomy

Oophorectomy: surgical removal of one or both ovaries (ovariectomy, ovariotomy), alone or with fallopian tubes as salpingo-oophorectomy. Performed for ovarian disease, cancer treatment, and genetic risk reduction; long-term trade-offs include surgical menopause and cardiovascular mortality.

Oct 20, 2026

OPAL BALANCE trial

OPAL Balance (NCT01976364) is Pfizer's open-label long-term extension of tofacitinib in psoriatic arthritis, following OPAL Broaden and OPAL Beyond; its randomised methotrexate withdrawal substudy found no clinically meaningful disease activity change after stopping methotrexate.