25,729 articles
UDFF study
A UDFF study evaluates ultrasound-derived fat fraction, a quantitative ultrasound technique combining attenuation and backscatter coefficients to estimate liver fat as a percentage, usually against MRI-PDFF.
Uganda Heart Institute
The Uganda Heart Institute is Uganda's national tertiary cardiac referral center at Mulago Hospital in Kampala, founded in 1988 and the only center offering both open-heart surgery and catheterisation.
Uhl anomaly
Uhl anomaly (parchment heart), an extremely rare congenital heart defect first described by Henry Uhl in 1952, in which right ventricular myocardium is absent, causing right heart failure and arrhythmias; fewer than 100 cases reported.
Ularitide
Ularitide (urodilatin, ESP-305) is a synthetic 32-amino-acid A-type natriuretic peptide, a kidney-derived vasodilator and natriuretic drug tested in the phase III TRUE-AHF trial for acute decompensated heart failure, which showed physiological effects but no mortality benefit.
Ulbright-Hodes syndrome
Ulbright-Hodes syndrome, also known as renal dysplasia-mesomelia-radiohumeral fusion syndrome, is an exceedingly rare autosomal recessive malformation disorder with dysplastic kidneys, limb reduction defects, and rib anomalies.
Ulcer (dermatology)
Ulcer (dermatology): a full-thickness loss of epidermis and dermis, a crater-like skin sore, also called skin ulcer, healing with scarring. Caused by inflammation, trauma, infection, poor circulation, pressure, or cancer; venous ulcers cause 60-80% of leg ulcers.
Ulcer of anus
Ulcer of anus (ICD-11.DB52) is a mucosal defect characterized by extension into the submucosa or deeper. It includes solitary, stercoral, and ulcer of anus and rectum.
Ulceration of conjunctiva
Ulceration of conjunctiva (conjunctival ulcer, ICD-11 9A60.30; SNOMED CT 95744009) is a necrotic depressed lesion of the eye's conjunctiva, infective (tuberculosis, herpes) or non-infective (Behçet's, Crohn's, mechanical), diagnosed by fluorescein staining.
Ulcerative colitis
Ulcerative colitis, also known as colitis ulcerosa, is a chronic inflammatory bowel disease causing inflammation and ulcers in the colon and rectum, with symptoms including bloody diarrhea and abdominal pain.
Ulcerative pancolitis
Ulcerative pancolitis (pancolitis, extensive colitis, Montreal E3) is ulcerative colitis inflaming the entire colon. ICD-10 K51.0, ICD-11 DD71.0; higher colorectal cancer risk, surveillance from about 8 years after onset.
Ulcerative proctitis
Ulcerative proctitis is inflammation of the rectal mucosa confined to the rectum, the mildest form of ulcerative colitis, causing rectal bleeding and urgency, treated first with rectal 5-ASA.
Ulcerative rectosigmoiditis
Ulcerative rectosigmoiditis, also called ulcerative proctosigmoiditis (ICD-11 DD71.2), is ulcerative colitis confined to the rectum and sigmoid colon; it is the most common extent at diagnosis, progresses proximally in up to about a third of patients, and is treated first with rectal mesalamine.
Ulceroglandular tularaemia
Ulceroglandular tularaemia, the commonest form of tularemia caused by Francisella tularensis, features a skin ulcer at the inoculation site with regional lymphadenopathy after tick, deer fly, or animal contact, treated with fluoroquinolones, gentamicin, or doxycycline.
Ulefnersen
Ulefnersen, also known as jacifusen or formerly ION363, is an investigational antisense oligonucleotide from Ionis Pharmaceuticals that met its Phase 3 FUSION endpoint in FUS-ALS in 2026.
Uliledlimab (TJD5)
Uliledlimab (尤莱利单抗, TJD5, TJ004309) is I-Mab's humanized anti-CD73 monoclonal antibody for solid tumors; non-competitive intra-dimer binding, tested with toripalimab and atezolizumab, now Phase 2/3 in NSCLC via TJ Biopharma and Sanofi.
Ulimorelin
Ulimorelin (TZP-101, LP101), a macrocyclic ghrelin receptor agonist prokinetic developed by Tranzyme Pharma for postoperative ileus; potent in phase 2b but failed phase 3 ULISES trials and was discontinued.
Ulinastatin
Ulinastatin (urinary trypsin inhibitor, UTI) is a Kunitz-type serine protease inhibitor glycoprotein from human urine, marketed in Asia for acute pancreatitis and studied in sepsis, cardiac surgery bleeding, and ARDS.
Ulipristal acetate
Ulipristal acetate (UPA, ella, ellaOne) is a selective progesterone receptor modulator taken as a single 30 mg pill within 120 hours for emergency contraception, delaying ovulation; more effective than levonorgestrel days 3-5, also studied at 5 mg for fibroids.
Ullrich congenital muscular dystrophy
Ullrich congenital muscular dystrophy (UCMD, Ullrich scleroatonic muscular dystrophy, OMIM 254090): severe collagen VI-related congenital muscular dystrophy from COL6A1/COL6A2/COL6A3 mutations, with proximal contractures, distal hyperlaxity, loss of ambulation and respiratory failure by about age 11.
Ulna
The ulna is the medial long bone of the human forearm, extending from the elbow to the wrist beside the radius, whose pivot around it produces pronation and supination.
Ulnar artery
The ulnar artery (arteria ulnaris) is the larger terminal branch of the brachial artery, supplying the medial forearm and most blood flow to the hand.
Ulnar claw
Ulnar claw, or claw hand (intrinsic-minus hand), is a deformity with MCP hyperextension and IP flexion of the ring and little fingers from ulnar nerve palsy, causing 60-80% pinch and grip strength loss; treated with splinting and tendon transfers.
Ulnar collateral ligament reconstruction
Ulnar collateral ligament reconstruction, or Tommy John surgery, replaces a torn elbow UCL with a tendon graft; first performed by Frank Jobe on pitcher Tommy John in 1974.
Ulnar nerve
Ulnar nerve (nervus ulnaris): terminal branch of the medial cord of the brachial plexus, C8–T1, supplying forearm flexors and most intrinsic hand muscles and medial 1.5 digits; compressed at cubital tunnel or Guyon canal.
Ulnar-mammary syndrome
Ulnar-mammary syndrome (Pallister ulnar-mammary syndrome, Schinzel syndrome, UMS): rare autosomal dominant TBX3 (12q24.21) disorder with ulnar limb defects, mammary/apocrine hypoplasia, genital anomalies, delayed puberty; ~128 reported cases.
Ulotaront
Ulotaront (SEP-363856) is an experimental antipsychotic acting at TAAR1 and 5-HT1A receptors without D2 blockade, developed for schizophrenia; its Phase 3 trials failed in 2023.
Ulrich Sigwart
Ulrich Sigwart (born 1941, Wuppertal) is a cardiologist who pioneered coronary stenting (Wallstent, first bailout implantation 1986) and invented alcohol septal ablation for hypertrophic obstructive cardiomyopathy; ESC Gold Medal 2025.
Ultra-low-field MRI
Ultra-low-field MRI (ULF MRI) is magnetic resonance imaging at field strengths far below conventional clinical scanners, trading image resolution for lower cost, portability, and use outside shielded rooms.
Ultrafast MRI
Ultrafast MRI is a magnetic resonance imaging technique that acquires images in tens of milliseconds to a few minutes, enabling sedation-free pediatric scans and stroke triage.
Ultrafast ultrasound imaging
Ultrafast ultrasound imaging is an ultrasound method that forms each frame with one unfocused transmission instead of line-by-line scanning, reaching 1,000 to 20,000 frames per second and enabling shear wave tracking and functional brain imaging.