25,729 articles
Organ donation
Organ donation: giving organs for transplantation from living donors (kidney, liver, lung, intestine portions) or deceased donors (kidney, liver, heart, lungs, pancreas, intestine), governed by OPTN allocation, preservation limits, and opt-in versus opt-out consent laws.
Organ donation for heart transplantation
Organ donation for heart transplantation covers DBD and DCD donor selection, 4-hour cold ischemia limits, machine perfusion, NRP ethics, and DCD trial outcomes showing noninferior 6-month survival versus brain-death donors.
Organ of Corti
Organ of Corti: the mammalian cochlea's hearing sensory epithelium, on the basilar membrane under the tectorial membrane; one inner and three outer hair-cell rows, tunnel of Corti, described by Corti in 1851.
Organ Preservation
Organ preservation keeps donor organs viable between procurement and transplant, mainly by static cold storage at 0–4 °C and machine perfusion (HMP, NMP), with cryopreservation as a long-term research goal.
Organ procurement
Organ procurement: surgical removal of organs, corneas, or tissue from donors for transplant, performed in the U.S. by about 55 nonprofit OPOs under OPTN and CMS oversight, with strict preservation time limits.
Organ Size
Organ size: measurement of a bodily organ in volume, mass, or heaviness (MeSH D009929, formerly Organ Weight). Covers biological size regulation and clinical measurement by CT, MRI, and ultrasound.
Organ Sparing Treatments
Organ Sparing Treatments (MeSH D059351): therapies on diseased organs that avoid complete removal and preserve function, e.g. organ-sparing cystectomy, rectal watchful waiting, partial nephrectomy, breast-conserving surgery.
Organ system
An organ system is a group of organs working together to carry out major body functions. The human body has eleven, including the nervous, cardiovascular, digestive, and respiratory systems.
Organ trade
Organ trade: the buying, selling, and brokering of human organs, also called organ trafficking and transplant tourism. Condemned by WHO and the Declaration of Istanbul; Iran alone permits legal paid kidney donation.
Organ transplantation
Organ transplantation: surgical replacement of failing organs (kidney, liver, heart, lung) with organs from living or deceased donors. Began with the 1954 twin kidney transplant; over 100,000 Americans now wait, mostly for kidneys.
Organization and Administration
Organization and Administration (MeSH D009934) is the planning and managing of programs, services, and resources in health care, covering governance, hospital and personnel administration, and performance measurement in health systems.
Organotherapy
Organotherapy, or opotherapy, is the historical treatment of disease with animal organ or gland extracts, launched by Brown-Séquard's 1889 testicular-extract self-experiment; thyroid and adrenal extracts worked, testicular extracts were placebo, and synthetic hormones replaced it.
Orgasmic dysfunctions
Orgasmic dysfunctions (ICD-11 HA02, orgasmic dysfunction) are WHO-classified sexual dysfunctions of the subjective orgasm experience, chiefly anorgasmia (HA02.0) with lifelong/acquired and generalised/situational subtypes, plus hypohedonic orgasm, postorgasmic illness syndrome, and painful orgasm under HA02.Y.
Orgone
Orgone is a hypothetical life energy proposed by Wilhelm Reich in the 1930s, tied to his bion research, orgone accumulators, and cloudbuster; it is dismissed as pseudoscience and led to Reich's 1957 imprisonment.
Orientation test
The orientation test is a bedside component of the mental status examination that probes a patient's awareness of person, place, time, and situation, documented as alert and oriented times three or four.
ORIGIN trial
ORIGIN trial (Outcome Reduction with an Initial Glargine Intervention), NCT00069784: 2x2 factorial RCT in 12,537 dysglycemic adults at high cardiovascular risk; insulin glargine and 1 g/day omega-3 both neutral for cardiovascular outcomes, cancer, and mortality over 6.2 years.
Oritavancin
Oritavancin (Orbactiv), a long-acting lipoglycopeptide antibiotic with ~393-hour half-life, is approved as a single 1200 mg IV dose for Gram-positive ABSSSI and studied off-label for osteomyelitis, bacteraemia, and endocarditis.
Oritinib mesylate (SH-1028)
Oritinib mesylate (SH-1028, rilertinib, 圣瑞沙) is Nanjing Sanhome's irreversible third-generation EGFR TKI for NSCLC; NMPA approved it in 2024 for T790M-positive second-line and first-line EGFR-mutated disease.
Orlistat
Orlistat (Xenical, alli; tetrahydrolipstatin) is a gastrointestinal lipase inhibitor weight-loss drug blocking about 30% of dietary fat absorption; 120 mg prescription and 60 mg OTC, with GI side effects and 2026 FDA kidney-injury warnings.
Ormeloxifene (centchroman)
Ormeloxifene (centchroman), sold in India as Saheli and Chhaya, is a non-steroidal SERM and once-weekly oral contraceptive developed by CSIR-CDRI, also used for abnormal uterine bleeding and mastalgia.
Ormutivimab
Ormutivimab (奥木替韦单抗, Xunke) is a recombinant human anti-rabies monoclonal antibody by North China Pharmaceutical, NMPA-approved January 2022 for rabies post-exposure prophylaxis, dosed 20 IU/kg.
Orna Guralnik
Orna Guralnik (born 1964) is an Israeli-American clinical psychologist and psychoanalyst in New York, NYU PostDoc faculty member, and star of Showtime's documentary series Couples Therapy since 2019.
Ornidazole
Ornidazole (Tiberal, Kolpicid) is a third-generation 5-nitroimidazole antiprotozoal and antibacterial drug with a 14-15 hour half-life, used for trichomoniasis, giardiasis, amoebiasis, bacterial vaginosis, and anaerobic infections.
Orofacial granulomatosis
Orofacial granulomatosis (OFG, ICD-11 DA01.21) is a rare chronic granulomatous inflammation of lips and mouth with non-caseating granulomas on biopsy, related to Crohn disease, treated with steroids, diet, and biologics.
Orofaciodigital syndrome type 1
Orofaciodigital syndrome type 1 (OFD1, Papillon-Léage-Psaume syndrome) is a rare X-linked dominant ciliopathy caused by OFD1 gene mutations, lethal in most males, causing oral, facial, and digital malformations plus polycystic kidney disease in females.
Orofaciodigital syndrome type 14
Orofaciodigital syndrome type 14 (OFD14, OMIM 615948) is a rare autosomal recessive ciliopathy caused by C2CD3 mutations on 11q13, marked by oral, facial, and digital malformations with severe microcephaly and molar tooth sign.
Orofaciodigital syndrome type 2
Orofaciodigital syndrome type 2 (OFD2, Mohr syndrome, OMIM 252100) is a rare autosomal recessive ciliopathy with cleft lip/palate, tongue nodules, dental agenesis, and poly-syn-brachydactyly; NEK1 variants found in one family.
Orofaciodigital syndrome type 4
Orofaciodigital syndrome type 4 (OFD4), Mohr-Majewski or Baraitser-Burn syndrome, is a rare autosomal recessive ciliopathy caused by TCTN3 variants, marked by postaxial polydactyly, tibial hypoplasia, oral anomalies, and kidney, liver, and brain involvement.
Orofaciodigital syndrome type 5
Orofaciodigital syndrome type 5 (Thurston syndrome, OFD5) is a rare autosomal recessive ciliopathy with postaxial polydactyly, median cleft of the upper lip, and DDX59 mutations on chromosome 1q32.
Orofaciodigital syndrome type 9
Orofaciodigital syndrome type 9 (OFD9, Gurrieri syndrome, OMIM 258865) is a rare autosomal recessive ciliopathy with oral, facial, and digital anomalies plus retinal coloboma; genes TBC1D32 and SCLT1.