25,729 articles
Upconversion nanoparticle photodynamic therapy
Upconversion nanoparticle photodynamic therapy (UCNP-PDT) is an experimental light-activated cancer and antimicrobial treatment in which lanthanide-doped nanoparticles convert deep-penetrating near-infrared light into visible light that activates a photosensitizer.
Upper airway resistance syndrome
Upper airway resistance syndrome (UARS), also called non-hypoxic sleep-disordered breathing, is a sleep-disordered breathing condition with RERAs and sleepiness but no apneas or desaturation; coined by Guilleminault in 1993 and subsumed under OSA in ICSD-3.
Upper airway stimulation
Upper airway stimulation is a surgical treatment for obstructive sleep apnea in which an implanted device stimulates the hypoglossal nerve during sleep, moving the tongue to keep the airway open.
Upper blepharoplasty
Upper blepharoplasty is a surgical procedure that removes excess skin, and sometimes muscle and fat, from the upper eyelid to treat drooping tissue (dermatochalasis) or reshape the lid.
Upper gastrointestinal bleeding
Upper gastrointestinal bleeding (UGIB, hematemesis, melena): bleeding from the esophagus, stomach, or duodenum above the ligament of Treitz. Incidence 80-150/100,000 yearly, mortality 7-11%; peptic ulcers cause ~44%; managed with resuscitation, endoscopy within 24 hours, and post-endoscopy proton pump inhibitors.
Upper gastrointestinal series
Upper gastrointestinal series, also called barium swallow or UGI, is a fluoroscopic x-ray exam of the esophagus, stomach, and duodenum using drunk barium contrast, with single- and double-contrast forms, used to find ulcers, reflux, hernias, strictures, and tumors.
Upper limb
Upper limb (upper extremity): the shoulder-to-fingers region of the human body, divided into arm, forearm, and hand, with 30 bones per limb, brachial plexus innervation, and manipulation-focused anatomy.
Upper limb deep vein thrombosis
Upper limb deep vein thrombosis (UEDVT, upper extremity DVT): thrombosis of deep arm veins (subclavian, axillary, jugular), 5–10% of all DVT; primary Paget-Schroetter/effort thrombosis versus catheter- or cancer-associated secondary forms.
Upper limb hypertrophy
Upper limb hypertrophy (ORPHA:295049, HPO HP:0010484) is abnormal enlargement of the arm, forearm, or hand from increased cell size, occurring isolated or in overgrowth syndromes such as Klippel-Trenaunay, Servelle-Martorell, and PIK3CA-related overgrowth spectrum.
Upper motor neuron
Upper motor neuron: cortical and brainstem neurons of the pyramidal (corticospinal and corticobulbar) tracts that synapse on lower motor neurons; lesions cause spasticity, hyperreflexia, clonus, and a positive Babinski sign.
Upper motor neuron lesion
Upper motor neuron lesion: damage to CNS motor neurons or the corticospinal/corticobulbar tracts above the anterior horn, causing weakness, spasticity, hyperreflexia, clonus, and the Babinski sign, distinct from lower motor neuron lesions.
Upper respiratory tract infection
Upper respiratory tract infection (URI, URTI): viral infection of the nose, sinuses, throat, and larynx; includes the common cold, sinusitis, tonsillitis, and laryngitis, caused by over 200 viruses, mainly rhinoviruses, and treated supportively.
Upper tract urothelial carcinoma
Upper tract urothelial carcinoma, sometimes called transitional cell carcinoma of the upper urinary tract, is a cancer of the urinary tract lining in the renal pelvis or ureter.
Uppsala University Hospital
Uppsala University Hospital (Akademiska sjukhuset), Sweden's oldest university hospital, founded 1708 as Nosocomium Academicum by Lars Roberg; regional hospital since 1961, part of Region Uppsala, about 1,000 beds, 8,000 staff, 700,000 patients yearly.
Uproleselan
Uproleselan (GMI-1271) is a glycomimetic E-selectin antagonist tested with chemotherapy in acute myeloid leukemia; phase 3 trials in relapsed/refractory and older newly diagnosed AML missed their primary survival endpoints.
UPSIDE Foods
UPSIDE Foods, formerly Memphis Meats, is a cultivated-meat company founded in 2015 by cardiologist Uma Valeti, which had raised $608 million as of July 2023.
Upward gaze deviation
Upward gaze deviation (ICD-11 9C83.11) is a conjugate upward deviation of both eyes, seen as paroxysmal tonic upgaze of childhood, oculogyric crisis, or posthypoxic sustained upgaze in coma.
Urachal carcinoma
Urachal carcinoma (UrC, urachal adenocarcinoma) is a rare cancer of the urachus remnant, under 1% of bladder cancers, incidence 0.04/100,000 person-years, mostly adenocarcinoma, treated by en-bloc partial cystectomy with umbilectomy.
Urachal cyst
Urachal cyst: a fluid-filled remnant of the urachus (allantois-derived bladder-umbilicus cord) with both ends closed and a patent central lumen; usually asymptomatic, prone to infection, rare malignancy risk in adults.
Urachal diverticulum
Urachal diverticulum (vesicourachal diverticulum, ORPHA:431347) is the rarest congenital urachal anomaly, a blind bladder-dome pouch from failed distal urachal closure, usually asymptomatic, managed conservatively first, with excision reserved for persistent symptomatic cases.
Urachal sinus
Urachal sinus (umbilical-urachal sinus), a congenital urachal anomaly where the umbilical end of the urachus stays open as a blind tract without bladder connection; presents with umbilical discharge, managed conservatively or by excision.
Uracil mustard
Uracil mustard (uramustine, NSC-34462) is an oral nitrogen mustard alkylating agent, FDA approved 1962 for CLL, CML, mycosis fungoides, and non-Hodgkin's lymphoma; discontinued 1999; main toxicity thrombocytopenia.
Urapidil
Urapidil (Ebrantil, B 66256) is a piperazine antihypertensive combining peripheral alpha-1 adrenoceptor blockade with central 5-HT1A agonism, used in Europe and Asia for hypertension and hypertensive emergencies; not marketed in the United States.
Urate-lowering therapy
Urate-lowering therapy (ULT) is drug treatment that reduces serum uric acid below the saturation point to dissolve crystals and prevent gout flares, using drugs such as allopurinol, febuxostat, and probenecid.
Urban Hospitals
Urban hospitals are hospitals located in metropolitan areas under a MeSH classification introduced in 1991; they are typically large, teach, and serve one-third of rural patients' hospital stays.
Urdhva patana
Urdhva patana (ūrdhvapātana), upward sublimation in Rasashastra: a classical Ayurvedic mercury-processing method using paired earthen pots to extract purified Parada from Hingula (cinnabar), yielding about 73% by Nada Yantra.
Urea breath test
The urea breath test (UBT) is a noninvasive diagnostic test in which swallowed labeled urea reveals active Helicobacter pylori infection, and it confirms cure after eradication therapy.
Ureaplasma parvum
Ureaplasma parvum, formerly U. urealyticum biovar 1, is a cell-wall-less human urogenital bacterium with serovars 1, 3, 6, 14, a 0.75–0.78 Mbp genome, and debated roles in preterm birth and neonatal lung disease.
URECA study
URECA (Urban Environment and Childhood Asthma) is an NIAID-sponsored US birth cohort of 560 high-risk inner-city children in Baltimore, Boston, New York City, and St. Louis, following immune development, urban exposures, and asthma through age 7 and beyond.
Uremia
Uremia (urémie): clinical syndrome of uremic toxin retention in blood from kidney failure, named 1847; symptoms include pericarditis and encephalopathy; treated by dialysis since Kolff's 1945 success.