72,234 articles
Histrionicus
Histrionicus, the harlequin ducks, a monotypic sea duck genus (Anatidae, Mergini) erected by Lesson in 1828; sole species H. histrionicus, the Harlequin Duck, breeding on fast rivers and wintering on rocky coasts.
Hiten Madhani
Hiten D. Madhani is an American molecular biologist, professor and vice-chair of biochemistry at UCSF, known for RNA interference and epigenetics research in the pathogenic fungus Cryptococcus neoformans.
Hitinder S. Gurm
Hitinder S. Gurm is an interventional cardiologist at the University of Michigan who directs the statewide BMC2 quality collaborative and serves as interim Chief Medical Officer of Michigan Medicine.
Hitoshi Kihara
Hitoshi Kihara (木原均) was a Japanese plant geneticist, born in 1893, who founded wheat genome analysis and identified Aegilops squarrosa as the ancestor of common wheat.
Hitoshi Kikutani
Hitoshi Kikutani is a Japanese immunologist and professor at Osaka University known for identifying CD23 as the IgE receptor and pioneering the immune semaphorin concept.
Hitoshi Kurumizaka
Hitoshi Kurumizaka (胡桃坂 仁志) is a Japanese structural biologist who heads the Laboratory of Chromatin Structure and Function at the University of Tokyo, known for his 2011 human centromeric nucleosome structure.
Hitoshi Sakano
Hitoshi Sakano (坂野 仁) is a Japanese neuroscientist at the University of Fukui known for the molecular identity code that sorts olfactory sensory axons in mice.
Hitoshi Takahashi
Hitoshi Takahashi (高橋 均) is a Japanese neuropathologist, professor emeritus at Niigata University, known for showing that α-synuclein accumulates in Lewy bodies in Parkinson's disease.
Hitting the wall
Hitting the wall, also called bonking, is the sudden debilitating fatigue striking marathon runners late in a race, typically after the 20-mile mark, conventionally attributed to depleted glycogen stores.
HIV
HIV (human immunodeficiency virus) is a retrovirus causing AIDS; 41.0 million people lived with HIV in 2025, ART suppresses it but no cure exists, and the 2030 end-of-epidemic goal faces funding cuts.
HIV test
An HIV test is a medical diagnostic test that detects HIV infection by measuring HIV-specific antibodies, the viral p24 antigen, or viral RNA in blood, serum, plasma, or oral fluid.
HIV trial
HIV trial NCT01195077 (Dietary Algae and HIV), a University of South Carolina phase I/II study led by Jane Teas testing Undaria seaweed and Spirulina in 12 antiretroviral-naive people with HIV; found no toxicity, improved quality of life, and stable CD4 and viral load.
HIV viral load measurement
HIV viral load measurement is a nucleic acid amplification test that quantifies HIV RNA in blood plasma, reported in copies per milliliter, to guide antiretroviral therapy and monitor treatment response.
HIV-1 protease
HIV-1 protease (HIV-1 PR) is an aspartic protease encoded by HIV-1 that cleaves viral Gag and Gag-Pol polyproteins into mature infectious virus, making it the target of ten protease inhibitors since saquinavir in 1995.
HIV-associated cancer
HIV-associated cancer: cancers occurring at elevated rates in people living with HIV, divided into AIDS-defining cancers (Kaposi sarcoma, aggressive non-Hodgkin lymphoma, cervical cancer) and non-AIDS-defining cancers, driven mainly by immunosuppression and oncogenic viruses.
HIV/AIDS
HIV is a lentivirus that causes AIDS, attacking the immune system by destroying CD4+ T cells. In 2025, 41 million people are living with the manageable chronic infection.
HIV/AIDS denialism
HIV/AIDS denialism rejects the consensus that HIV causes AIDS, claiming drugs, malnutrition, or lifestyle instead. Traced to Peter Duesberg's 1987 article; under President Mbeki it cost an estimated 330,000 lives in South Africa, and it resurged online in the COVID era.
HIV/AIDS epidemic in Southern Africa
The HIV/AIDS epidemic in Southern Africa is the world's most severe regional HIV epidemic, with South Africa alone home to about 8 million people living with HIV.
HIV/AIDS in Africa
HIV/AIDS in Africa: the world's hardest-hit regional HIV epidemic, with 64% of 41 million people living with HIV in the WHO African Region, heterosexual transmission, ART-driven life-expectancy gains, and a 2025 US funding crisis threatening PEPFAR-supported treatment.
HIV/AIDS in India
HIV/AIDS in India, also called AIDS in India, is the national HIV epidemic: 2.561 million people living with HIV in 2024, with adult prevalence of just 0.20%.
HIV/AIDS in Kenya
HIV/AIDS in Kenya is a generalized epidemic, first detected in 1984, that peaked at roughly 10 to 13 percent in the late 1990s and fell to 3.22% by 2026.
HIV/AIDS in South Africa
HIV/AIDS in South Africa is the world's largest national HIV epidemic, with about 8 million people living with HIV, and runs the largest antiretroviral treatment program.
HIV/AIDS in the Philippines
HIV/AIDS in the Philippines: epidemic since the 1984 first case, long "low and slow," now the fastest-growing HIV surge in Asia-Pacific under RA 8504 and RA 11166, with 4,633 new cases in Q1 2026.
HIV/AIDS in the United States
HIV/AIDS in the United States: the domestic HIV epidemic first reported June 5, 1981; over 1.2 million Americans living with HIV, about 38,000 new diagnoses in 2024, concentrated among men, Black and Hispanic people, and the South.
HIV/AIDS in Uganda
HIV/AIDS in Uganda is the national experience of a severe HIV epidemic that fell from about 15 percent of adults around 1991 to about 5 percent by 2001.
HIV/AIDS-related lymphoma
HIV/AIDS-related lymphoma, or AIDS-related lymphoma, is aggressive B-cell non-Hodgkin lymphoma (DLBCL, Burkitt, primary CNS lymphoma) arising in people with HIV, linked to EBV and HHV8, with incidence and outcomes transformed by antiretroviral therapy.
Hive tool
Hive tool: the beekeeper's flat metal lever for opening propolis-glued hives, lifting frames, and scraping wax. Main types are the standard American pry bar, J-hook, and frame grip; stainless steel, 20 to 38 cm.
Hives
Hives (urticaria): itchy wheals from mast cell histamine release, acute or chronic (over 6 weeks). Treated with second-generation H1-antihistamines up to fourfold, then omalizumab, then ciclosporin.
Hjalmar August Schiøtz
Hjalmar August Schiøtz (1850–1927) was a Norwegian ophthalmologist who introduced the indentation tonometer bearing his name in 1905, for decades the world's standard for measuring eye pressure.
HJV
HJV (hemojuvelin BMP co-receptor, HFE2, RGMC) is a human gene on chromosome 1q21.1 encoding hemojuvelin, a GPI-anchored BMP co-receptor that drives hepcidin production; HJV mutations cause autosomal recessive type 2A juvenile hemochromatosis, most often G320V.