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Holmes-Adie syndrome
Holmes-Adie syndrome, also called Adie syndrome or tonic pupil-tendon areflexia syndrome, is a benign disorder of ciliary ganglion denervation causing a tonic pupil with light-near dissociation plus absent tendon reflexes, described by Adie and Holmes in 1931.
Holmium laser enucleation of the prostate
Holmium laser enucleation of the prostate (HoLEP) is a transurethral operation for benign prostatic hyperplasia that peels the entire adenoma away and morcellates it, working for glands of any size.
Holocarboxylase synthetase
Holocarboxylase synthetase (HCS/HLCS) is the mammalian biotin protein ligase that attaches biotin to five carboxylases via biotinyl-AMP; its deficiency causes neonatal multiple carboxylase deficiency, treated with high-dose biotin.
Holocarboxylase synthetase deficiency
Holocarboxylase synthetase deficiency (HLCS deficiency, early-onset multiple carboxylase deficiency) is an autosomal recessive disorder of biotin metabolism caused by HLCS gene mutations, presenting in infancy with metabolic acidosis, rash, and seizures, treated with oral biotin.
Holocene and modern bivalve sclerochronology calibration studies
Bivalve sclerochronology calibration links shell growth increments and shell chemistry, especially δ18O, to dated instrumental climate measurements, turning Holocene and older bivalve shells into quantitative paleoclimate records.
Holocene extinction
Holocene extinction, also called the sixth mass extinction or Anthropocene extinction: ongoing human-driven species loss during the last ~11,500 years, with modern extinction rates estimated at tens to hundreds of times background levels, though its mass-extinction status is debated.
Holocentric chromosome
Holocentric chromosome (holokinetic, diffuse centromere): a chromosome with kinetochore activity along nearly its whole length, tolerating fragmentation; evolved independently at least 13 times in plants and animals, first described 1935.
Holocephali
Holocephali, also known as holocephalans, is a subclass of cartilaginous fish containing the chimaeras, or ghost sharks, with upper jaws fused to the skull and a fossil record reaching back almost 360 million years.
Holochilus
Holochilus (marsh rats) is a genus of large, semiaquatic, herbivorous sigmodontine rodents in open wetlands across South America, from northern South America to central Argentina, with six or more recognized species and a complex taxonomic history.
Holodiscus discolor
Holodiscus discolor, oceanspray or creambush (Rosaceae), a deciduous arching shrub native from British Columbia to Mexico, with creamy white flower sprays, four varieties, fire-adapted, valuable to native bees.
Holometabolism
Holometabolism (complete metamorphosis, Holometabola/Endopterygota) is insect development through egg, larva, pupa, and adult stages, seen in nearly 90% of insect species including beetles, flies, bees, and butterflies, controlled by ecdysone, juvenile hormone, chinmo, broad, and E93.
Holoprosencephaly
Holoprosencephaly (HPE) is the most common human forebrain malformation, in which the cerebral hemispheres fail to separate. Alobar, semilobar, lobar, and MIH forms; SHH pathway disruption; about 1 in 10,000 live births.
Holoprosencephaly-postaxial polydactyly syndrome
Holoprosencephaly-postaxial polydactyly syndrome, or pseudotrisomy 13 (OMIM 264480, ORPHA:2166), is a rare autosomal recessive malformation syndrome with holoprosencephaly, postaxial polydactyly, severe facial anomalies, and a normal karyotype, mimicking trisomy 13.
Holoprosencephaly-radial heart renal anomalies syndrome
Holoprosencephaly-radial heart renal anomalies syndrome, or Steinfeld syndrome (OMIM 184705, ORPHA 3186), is a rare autosomal dominant disorder combining holoprosencephaly, radial limb defects, heart and kidney malformations, and absent gallbladder.
Holothuria (genus)
Holothuria Linnaeus, 1767, type genus of the sea cucumber class Holothuroidea; about 150–163 tropical shallow-water species in 18 subgenera, order Holothuriida, family Holothuriidae; several species commercially harvested and IUCN-listed.
Holothuria mexicana
Holothuria mexicana, the donkey dung sea cucumber (Ludwigothuria mexicana), is a large Caribbean holothuriid sea cucumber up to about 50 cm, the region's most abundant and commercially important species, fished seasonally in Honduras and Belize and proposed for CITES Appendix II.
Holothuria scabra
Holothuria scabra, the sandfish, is a high-value tropical sea cucumber of the Indo-Pacific sold dried as beche-de-mer; it is the only tropical holothuroid mass-produced in hatcheries and is heavily overfished.
Holothuroid systematics and phylogeny
Holothuroid systematics and phylogeny is the higher-level classification of sea cucumbers, where the traditional five-order scheme has been replaced by orders derived from molecular phylogenies.
Holt-Oram syndrome
Holt-Oram syndrome (heart-hand syndrome type 1, HOS) is an autosomal dominant disorder caused by TBX5 mutations on 12q24.1, combining radial-ray upper-limb defects, septal heart defects, and cardiac conduction disease; prevalence about 1 per 100,000 births.
Holter monitor
Holter monitor: wearable ambulatory ECG device recording heart rhythm continuously for 24-48 hours; invented by Norman J. Holter in the 1950s, patented 1965, used to detect arrhythmias.
Homalodisca vitripennis
Homalodisca vitripennis, the glassy-winged sharpshooter, is a large xylem-feeding leafhopper native to the southeastern United States and northeastern Mexico and the primary vector of the bacterium causing Pierce's disease of grapevines.
Homarus
Homarus is a genus of clawed lobsters with two living species, the American lobster (Homarus americanus) and European lobster (H. gammarus), the world's most valuable lobster fisheries, plus six fossil taxa from the Cretaceous onward.
Homarus gammarus
Homarus gammarus, the European lobster (FAO code LBE), is a clawed nephropid lobster from northern Norway to Morocco and the Mediterranean; landings near 5,000 t yearly, far below the American lobster's 150,000 t.
Home Care Services
Home Care Services: health and supportive care delivered at home, including skilled nursing, therapy, aide, and hospice services. Funded mainly by Medicaid (~40% of LTC spending) and Medicare's 60-day-episode home health PPS; distinct from institutional nursing home care.
Home Environment
Home Environment: the physical and social conditions of a dwelling affecting health, a 2022 MeSH term (D000091502) covering housing quality, living alone, hazards, and neighborhood context.
Home garden
Home garden, also called kitchen, backyard or homestead garden: small-scale household food production system near the dwelling, supplying over 50 percent of a family's vegetables and fruits and supplementary income.
Home Health Aides
Home health aides (also home care aides, personal care aides) are supervised paraprofessional caregivers who assist elderly, disabled, and chronically ill clients with daily living and basic health tasks in the home; about 4.7 million U.S. jobs, median pay $35,800 (May 2025), 18% projected growth 2025-2035.
Home hemodialysis
Home hemodialysis is a renal replacement therapy in which a kidney failure patient performs dialysis at home on flexible schedules of two to seven sessions weekly.
Home Infusion Therapy
Home infusion therapy is the administration of medications, fluids, or nutrients in a patient's home, typically intravenously or subcutaneously, for infections, immune disorders, and cancer, often at lower cost than hospital care.
Home Nursing
Home nursing is skilled clinical nursing care delivered in a patient's home, distinct from aide-provided personal care; covered under Medicare with homebound criteria, measured by CMS star ratings, and supported by hospital-at-home evidence.