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Hemagglutination Tests
Hemagglutination tests (HA, HI/HAI, Hirst test) detect and quantify viruses or antibodies by visible clumping of red blood cells via viral hemagglutinin; used for influenza diagnosis, vaccine antigenic characterization, and blood group typing.
Hemagglutinin (influenza)
Influenza hemagglutinin (HA), the major surface glycoprotein of influenza A and B viruses, binds sialic acid receptors and mediates low-pH membrane fusion; it is the main target of neutralizing antibodies, antigenic drift, and seasonal and universal flu vaccines.
Hemagglutinin esterase
Hemagglutinin esterase is a family of viral glycoproteins that bind O-acetylated sialic acids; the best-known member is HEF, the single spike protein of influenza C virus.
Hemanatha rasa
Hemanatha rasa (Hemnath Ras), a classical Ayurvedic herbo-mineral rasa formulation from Bhaishajya Ratnavali 86/43-47, made from kajjali (mercury-sulfur) with gold, iron, coral and tin bhasmas, dosed 375 mg for urinary disorders.
Hemangioblast
Hemangioblast: a transient mesoderm-derived progenitor giving rise to both endothelial and hematopoietic cells, proposed by Sabin (1917), named by Murray (1932); demonstrated via BL-CFCs in embryoid bodies and zebrafish fate mapping, distinct from hemogenic endothelium.
Hemangioblastoma
Hemangioblastoma: benign WHO grade 1 vascular tumor of the CNS, mostly cerebellum and spinal cord; sporadic or von Hippel-Lindau (VHL)-associated; treated by resection or stereotactic radiosurgery.
Hemangioma
Hemangioma: a benign vascular tumor of clumped blood vessels; infantile hemangioma (strawberry mark) is the most common benign tumor of infancy, grows then involutes, treated with propranolol; distinct from vascular malformations; cherry and liver forms also occur.
Hemangiosarcoma
Hemangiosarcoma (HSA), also called angiosarcoma, is a malignant tumor of blood vessel endothelial cells, typically affecting the spleen or heart of older, large-breed dogs; rare in humans, treated by surgery plus doxorubicin with poor prognosis.
Hematemesis
Hematemesis, vomiting of blood, signals upper GI bleeding from peptic ulcers, varices, or Mallory-Weiss tears; distinguished from hemoptysis by acidic, coffee-ground vomit and managed with endoscopy.
Hematidrosis
Hematidrosis, also called hematohidrosis or bloody sweat, is a rare eccrine sweat disorder in which blood-tinged fluid oozes from intact skin, typically under extreme stress; ICD-10 L74.8, treated with beta-blockers such as propranolol.
Hematin
Hematin is an iron-containing porphyrin, the hydroxide-ligated form of protoporphyrin IX related to hemin, whose crystallization into hemozoin in malaria parasites is targeted by quinoline antimalarials.
Hematochezia
Hematochezia, or bright red blood per rectum, is passage of fresh red or maroon blood from the rectum, usually from lower GI bleeding (diverticula, angiodysplasia, neoplasms, colitis, hemorrhoids) but occasionally a brisk upper GI bleed with hemodynamic instability.
Hematocrit
Hematocrit (HCT, packed cell volume, PCV) is the percentage of blood volume made up of red blood cells, measured by centrifugation or calculated by automated Coulter-principle analyzers; typical adult ranges are 41–50% for men and 36–47% for women, used to assess anemia, polycythemia, and dehydration.
Hematodinium
Hematodinium (type species H. perezi) is a genus of parasitic dinoflagellates in the order Syndiniales that infects the hemolymph of marine crabs, lobsters, and shrimp, causing Bitter Crab Disease and major aquaculture losses in China.
Hematology
Hematology is the branch of internal medicine concerned with blood, blood-forming organs, and blood diseases, including anemias, clotting disorders, and blood cancers such as leukemia and lymphoma.
Hematoma
Hematoma: a localized collection of clotted blood outside blood vessels in an organ, tissue, or body space; also called a bruise (contusion) when superficial. Types include subdural, epidural, subungual, and auricular hematomas.
Hematophagy
Hematophagy, also called sanguivory, is the feeding habit of animals that ingest the blood of other animals, best known in mosquitoes, ticks, and vampire bats.
Hematopoietic cell
Hematopoietic cell: any blood-forming cell, from self-renewing hematopoietic stem cells through progenitors to mature erythrocytes, leukocytes, and platelets; hierarchy, niches, epigenetics, and transplantation.
Hematopoietic cell signal transducer
HCST (DAP10, KAP10, PIK3AP) is a human chromosome 19 gene encoding a 93-aa transmembrane immune adaptor that pairs with NKG2D, recruits PI3K and Grb2-Vav1 via its YINM motif, and drives NK and CD8 T cell cytotoxicity.
Hematopoietic multipotent progenitor cell
Hematopoietic multipotent progenitor (MPP) cells are short-term, self-renewal-limited descendants of hematopoietic stem cells that generate multiple blood lineages; subtypes include FLT3+ LMPPs, myeloid- and erythroid-biased human MPPs, and HSC-independent embryonic eMPPs.
Hematopoietic stem cell
The hematopoietic stem cell, or blood stem cell, is a bone marrow cell that renews itself for life and gives rise to all blood cell types, including white cells, red cells, and platelets.
Hematopoietic Stem Cell Mobilization
Hematopoietic stem cell mobilization moves HSCs from bone marrow to blood for apheresis before transplantation, using G-CSF, CXCR4 inhibitors like plerixafor, or cyclophosphamide chemo-mobilization; about 15% of patients mobilize poorly.
Hematoporphyrin Photoradiation
Hematoporphyrin photoradiation, or photodynamic therapy (PDT), is a form of photochemotherapy using visible light applied locally or topically to destroy diseased tissue. Its initial application was described in 1903.
Hematoxylin and eosin staining
Hematoxylin and eosin (H&E) staining is a histological method that turns cell nuclei blue-purple and cytoplasm pink, and is the most widely used stain for cancer diagnosis.
Hematuria
Hematuria, blood in the urine, is gross (visible) or microscopic (≥3 RBC/HPF on urinalysis). Causes range from infection, stones, and BPH to urinary tract cancer; AUA/SUFU guidelines stratify evaluation by malignancy risk.
Heme
Heme (protoheme IX, Fe-protoporphyrin IX) is an iron-porphyrin cofactor of hemoglobin, cytochromes, and P450 enzymes; ferrous form is heme, ferric form is hemin, with types a, b, c, d, and o.
Heme biosynthesis
Heme biosynthesis, the eight-step pathway producing heme (protoheme IX) from glycine, succinyl-CoA, and iron across mitochondria and cytosol; includes classical PPD route plus CPD and AHB alternatives; defects cause porphyrias.
Heme degradation
Heme degradation is the two-step catabolism of heme by heme oxygenase and biliverdin reductase to bilirubin, carbon monoxide, and iron; humans degrade about 300 mg heme daily, mostly from hemoglobin.
Heme oxygenase
Heme oxygenase (HO, EC 1.14.14.18), also called haem oxygenase, is the rate-limiting enzyme degrading heme into biliverdin, carbon monoxide, and free iron. Isoforms HO-1 (inducible, HSP32) and HO-2 (constitutive) protect cells from oxidative stress.
Heme oxygenase-1 deficiency
Heme oxygenase-1 deficiency (HMOX1D, HO-1 deficiency) is a rare autosomal recessive HMOX1 disorder with asplenia, hemolytic anemia, low bilirubin, hyperinflammation, nephritis, and endothelial injury; first reported 1999.