25,729 articles
Homer family
Homer family (Homer1, Homer2, Homer3; Vesl) proteins: postsynaptic density adaptor proteins binding mGluR1/5, IP3 receptors, and Shank via EVH1 domains; long forms multimerize, short Homer1a is an activity-induced dominant negative.
Hominy
Hominy: dried corn kernels treated with an alkali (lye or limewater) via nixtamalization, removing the hull; the Nahuatl-derived nixtamal. Basis of pozole, menudo, grits, and masa; adds calcium and improves niacin bioavailability.
Homocysteine
Homocysteine, a sulfur amino acid from methionine metabolism (hyperhomocysteinemia >15 µmol/L), is lowered by B vitamins, but trials show no reduction in heart attack or death; used mainly for B-vitamin deficiency and homocystinuria testing.
Homocystinuria
Homocystinuria (HCU), also called classic homocystinuria when caused by CBS deficiency, is a rare autosomal recessive metabolic disorder of homocysteine breakdown, causing lens dislocation, skeletal changes, and thromboembolism, treated with vitamin B6, low-methionine diet, and betaine.
Homocystinuria without methylmalonic aciduria
Homocystinuria without methylmalonic aciduria (functional methionine synthase deficiency; cblE, cblG, cblDv1) is a rare autosomal recessive cobalamin metabolism disorder with megaloblastic anemia, high homocysteine, low methionine, and normal methylmalonic acid, treated with hydroxocobalamin.
Homonymous hemianopsia
Homonymous hemianopsia (homonymous hemianopia): loss of the same half of the visual field in both eyes from retrochiasmal lesions (optic tract, LGN, radiations, occipital cortex), usually stroke; macular sparing localizes to occipital cortex.
Homosynaptic plasticity
Homosynaptic plasticity: activity-dependent change (LTP or LTD) at synapses that were themselves active during induction, Hebbian, input-specific, NMDA receptor and calcium dependent, distinct from heterosynaptic plasticity at unstimulated synapses.
Homozygous familial hypercholesterolemia
Homozygous familial hypercholesterolemia (HoFH), also called bi-allelic FH, is a rare autosomal semi-dominant disorder with LDL-C above 10 mmol/L from birth, caused mainly by LDLR variants, and treated with statins, ezetimibe, PCSK9 inhibitors, evinacumab, lomitapide, and apheresis.
HOPE COVID 19 study
HOPE COVID-19 (Health Outcome Predictive Evaluation for COVID-19, NCT04334291) is an international investigator-initiated observational registry of 8,168 hospitalized COVID-19 patients led from Hospital Clínico San Carlos, Madrid, studying mortality, prognostic scores, and treatments; HOPE-II is its 55-center successor.
HOPE trial (NCT05550584)
HOPE trial (NCT05550584), Italian randomized non-inferiority study at Gemelli IRCCS comparing THRIVE high-flow nasal oxygen (70 L/min) with I-Gel laryngeal mask ventilation during operative hysteroscopy under anesthesia; 180 patients, completed May 2023; distinct from stroke and liver HOPE trials.
Hôpital Beaujon
Hôpital Beaujon, AP-HP hospital in Clichy (Hauts-de-Seine), France; short-stay adult CHU of GHU Nord – Université Paris Cité; opened 1935 as France's first monobloc high-rise hospital; digestive and head-neck-spine excellence; moving to Saint-Ouen in 2031.
Hôpital Cochin
Hôpital Cochin is a public university hospital in Paris belonging to Assistance publique – Hôpitaux de Paris, founded in 1780 by Jean-Denis Cochin, with sites at Cochin, Port-Royal, and Tarnier.
Hôpital Lariboisière
Hôpital Lariboisière (Hôpital Lariboisière – Fernand-Widal), AP-HP university hospital in Paris's 10th arrondissement. Inaugurated 1854, France's first pavilion-plan hospital, funded by comtesse Élisa de Lariboisière's bequest; architect Martin-Pierre Gauthier.
Hôpital Notre-Dame
Hôpital Notre-Dame, Montreal hospital founded 1880 by Dr Emmanuel Persillier-Lachapelle; first secular Francophone hospital in North America, at 1560 Sherbrooke Est, now part of CIUSSS Centre-Sud-de-l'Île-de-Montréal.
Hôpital Saint-Antoine
Hôpital Saint-Antoine, AP-HP public teaching hospital in Paris's 12th arrondissement, on the site of the 1198 abbaye Saint-Antoine-des-Champs; 665 beds, CRSA Inserm/Sorbonne research unit, AP-HP headquarters since 2022.
Hôpital Saint-Louis
Hôpital Saint-Louis is a public AP-HP teaching hospital in Paris's 10th arrondissement, founded by Henri IV's 1607 edict as a plague isolation hospital, birthplace of French dermatology, and a reference center for hematology, oncology, transplantation, and burns.
Hôpital Tenon
Hôpital Tenon is a public teaching hospital of the Assistance Publique–Hôpitaux de Paris in the 20th arrondissement of Paris, opened in 1878, where singer Édith Piaf was born in 1915.
Hopkins Symptom Checklist
The Hopkins Symptom Checklist (HSCL) is a family of self-report questionnaires measuring depression and anxiety symptoms, used in clinical screening and psychiatric research since 1974.
Horace Wells
Horace Wells (1815–1848), American dentist of Hartford, Connecticut, discoverer of anesthesia; first used nitrous oxide for tooth extraction on 11 December 1844, failed in Boston 1845, died by suicide, recognized by ADA 1864 and AMA 1870.
Hordeolum internum
Hordeolum internum (internal hordeolum, internal stye): acute bacterial infection, usually Staphylococcus aureus, of a meibomian gland inside the eyelid; deeper and more diffuse than an external stye, treated with warm compresses, resolving in 1–2 weeks.
Horizontal conjugate gaze deviation
Horizontal conjugate gaze deviation: both eyes tonically deviated in the same horizontal direction; radiographic form (Rad h-CGD) localizes stroke, seizure, brainstem, and vestibular causes; ICD-11 9C83.10.
Horizontal gaze palsy
Horizontal gaze palsy: inability to move both eyes conjugately in a horizontal direction, usually from a pontine lesion of the PPRF or abducens nucleus (stroke, MS, hemorrhage); congenital form is HGPPS from ROBO3 mutations; ICD-11 9C83.00.
Hormonal Contraception
Hormonal contraception: progestin-only or combined estrogen-progestin methods (pills, implant, injection, patch, ring, LNG-IUD) preventing pregnancy mainly by stopping ovulation; first pill Enovid, FDA-approved May 1960; implant 0.1% typical failure rate; no STI protection.
Hormone replacement therapy
Hormone replacement therapy (HRT, menopausal hormone therapy) replaces estrogen and progestogen to treat menopause symptoms; shaped by the 2002 WHI trial and the FDA's 2025-2026 removal of boxed warnings.
Hormone research in pædiatrics
Hormone research in pædiatrics (Horm Res Paediatr), Karger's monthly peer-reviewed pediatric endocrinology journal since 2010, formerly Hormones (1970) and Hormone Research; official journal of ESPE, PES, and SLEP; 2025 Impact Factor 3.8.
Horner's syndrome
Horner's syndrome (oculosympathetic paresis) is the triad of miosis, ptosis, and anhidrosis from disruption of the three-neuron sympathetic pathway to the eye; described by Horner in 1869, confirmed with apraclonidine or cocaine testing, and localized with hydroxyamphetamine.
Horseshoe kidney
Horseshoe kidney, a congenital renal fusion anomaly (fused kidney, renal fusion), joins both kidneys at the lower poles via an isthmus; affects about 1 in 500 people, causing stones, PUJ obstruction, reflux, and elevated malignancy risk.
Horticultural Therapy
Horticultural therapy is the use of plants and gardening activities, guided by a trained therapist, to promote healing and rehabilitation; it became a distinct profession in the mid-twentieth century.
Hospice
Hospice: comfort-focused end-of-life care for terminally ill patients and families, rooted in Cicely Saunders' 1967 St Christopher's Hospice and a US Medicare benefit since 1982; four care levels, 6-month prognosis certification, over $23 billion in annual Medicare spending.
Hospices Civils de Lyon
Hospices Civils de Lyon (HCL), Lyon's public university hospital system, second CHU of France, founded 1802, about 24,000 staff, HCL 2035 strategy, BAURéaLS project at Lyon Sud.