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H
Helvella - heme synthase

Helvella (Hel·vel·la) (hel-vel´ə)  the saddle fungi, a genus of the family Helvellaceae. Some species contain a heat-stable hemolysin. H. esculen´ta and other species cause mycetismus sanguinarius, a form of mushroom poisoning.

Helvellaceae (Hel·vel·la·ceae) (hel”vəl-a´se-e)  a family of fungi of the order Pezizales; some species are edible and others are poisonous. It includes the genera Gyromitra and Helvella.

Helweg's bundle (tract) (Hel·weg's bundle (tract)) (hel´vegz) [Hans Kristian Saxtorph Helweg, Danish physician, 1847–1901]  olivospinal tract.

Helweg-Larsen's syndrome (Hel·weg-Lar·sen's syndrome) (hel´veg-lahr´sənz) [Hans F. Helweg-Larsen, Danish dermatologist, 20th century]  see under syndrome.

hema (he·ma) (he´mə) [Gr. haima, haimatos blood]  haema; see also blood.

hema- (hema-)  see hem(o)-.

Hemabate (Hema·bate) (he´mə-bāt)  trademark for a preparation of carboprost tromethamine.

hemachromatosis (hema·chro·ma·to·sis) (he”mə-kro”mə-to´sis)  hemochromatosis.

hemachrome (hema·chrome) (he´mə-krōm)  an oxygen-carrying blood pigment, e.g., hemoglobin or hemocyanin.

hemacyte (hema·cyte) (he´mə-sīt)  blood cell.

hemacytometer (hema·cy·tom·e·ter) (he”mə-si-tom´ə-tər)  a device used in manual blood counts, consisting of a microscopic slide with a depression whose base is marked in grids, and into which a measured volume of a sample of blood or bacterial culture is placed and covered with a cover glass. The number of cells and formed blood elements in the squares is counted under a microscope and used as a representative sample for calculating the unit volume. Called also counting cell, counting chamber, and hemocytometer.

hemacytometry (hema·cy·tom·e·try) (hēm”ə-si-tom´ə-tre)  the counting of blood cells using a hemacytometer; called also hemocytometry.

hemadostenosis (he·ma·do·ste·no·sis) (he”mə-do-, hem-ə-to-stə-no´sis)  stenosis of a blood vessel; see also angiostenosis.

hemadsorbent (he·mad·sor·bent) (he”mad-zor´bənt)  inducing or characterized by hemadsorption.

hemadsorption (he·mad·sorp·tion) (he”mad-zorp´shən)  the adherence of red cells to other cells, particles, or surfaces; see hemadsorption test, under test.

hemadynamometry (he·ma·dy·na·mom·e·try) (he”mə-di”nə-mom´ə-tre)  measurement of blood pressure.

hemafacient (he·ma·fa·cient) (he”mə-fa´shənt)  hematopoietic.

hemagglutination (he·mag·glu·ti·na·tion) (he”mə-gloo”tĭ-na´shən)  agglutination of erythrocytes, which may be caused by antibodies such as hemagglutinins, by viruses such as those of influenza and mumps, or by other substances such as lectins.

indirect h. ,  passive h.  agglutination of erythrocytes due to the reaction of specific antibody with antigen passively adsorbed on the surface or chemically coupled to the cells; the basis of many serologic tests.

viral h.  the agglutination of erythrocytes by viruses, either by intact virions or by viral products; the basis of hemagglutination or hemagglutination inhibition methods for viral titration.

hemagglutinative (he·mag·glu·ti·na·tive) (he”mə-gloo´tĭ-na”tiv)  pertaining to, characterized by, or causing agglutination of erythrocytes.

hemagglutinin (he·mag·glu·ti·nin) (he”mə-gloo´tĭ-nin) [hem- + agglutinin]  an agglutinin, e.g., an antibody or lectin, that agglutinates erythrocytes.

cold h.  a cold agglutinin (q.v.) that agglutinates red cells.

warm h.  a warm agglutinin (q.v.) that agglutinates red cells.

hemal (he·mal) (he´məl)  1. ventral to the spinal axis, where the heart and great vessels are located, as, e.g., the hemal arches. Cf. neural.  2. hemic.  3. pertaining to the blood vessels; see vascular.

hemalum (hem·al·um) (he´mə-ləm)  a mixture of hematoxylin and alum introduced by Mayer, widely used as a nuclear stain, especially in combination with eosin as a general oversight method. Also, any alum and hematoxylin stain. Called also alum hematoxylin.

hemanalysis (hem·a·nal·y·sis) (he”mə-nal´ə-sis) [hem- + analysis]  analysis or examination of the blood.

hemangiectasia (he·man·gi·ec·ta·sia) (he-man”je-ek-ta´shə)  angiectasis.

hemangiectasis (he·man·gi·ec·ta·sis) (he-man”je-ek´tə-sis)  angiectasis.

hemangi(o)- (hemangi(o)-) [Gr. haima blood + angeion vessel]  a combining form denoting relationship to the blood vessels.

hemangioameloblastoma (he·man·gio·amelo·blas·to·ma) (he-man”je-o-ə-mel”o-blas-to´mə) [hemangio- + ameloblastoma]  a highly vascular ameloblastoma.

hemangioblast (he·man·gio·blast) (he-man´je-o-blast) [hemangio- + -blast]  a mesodermal cell which gives rise to both vascular endothelium and hemocytoblasts.

hemangioblastoma (he·man·gio·blas·to·ma) (he-man”je-o-blas-to´mə) [hem- + angioblast + -oma]  a benign blood vessel tumor of the cerebellum, spinal cord, or retina, consisting of proliferated blood vessel cells and angioblasts. Called also angioblastoma and Lindau's tumor.

cerebellar h.  hemangioblastoma of the cerebellum, often cystic; an autosomal dominant form is associated with von Hippel-Lindau disease.

retinal h.  von Hippel's disease.

spinal h.  a hemangioblastoma of the spinal cord, usually small and encapsulated and in an intramedullary location.

hemangioblastomatosis (he·man·gio·blas·to·ma·to·sis) (he-man”je-o-blas”to-mə-to´sis)  multiple or widespread hemangioblastomas.

hemangioendothelioblastoma (he·man·gio·en·do·the·lio·blas·to·ma) (he-man”je-o-en”do-the”le-o-blas-to´mə) [hemangioendothelioma + blastoma]  a hemangioendothelioma with embryonic elements of mesenchymal origin.

hemangioendothelioma (he·man·gio·en·do·the·lio·ma) (he-man”je-o-en”do-the”le-o´mə) [hemangioma + endothelioma]  a true neoplasm of vascular origin, characterized by proliferation of endothelial cells in and about the vascular lumen; it is usually considered to be intermediate in grade between hemangioma and hemangiosarcoma but sometimes is used to denote the latter.

benign h.  a benign neoplasm of blood-vessel endothelium; the term is usually used to denote an infantile hemangioendothelioma.

epithelioid h.  a rare vascular neoplasm occurring in the medium to large veins of the distal extremities of adults, particularly young males; it may be benign or malignant and is characterized by proliferation of epithelioid or histiocytoid endothelial cells lining dilated vascular channels.

infantile h.  a rare, benign tumor of the liver in infants, generally multicentric, composed of anastomosing vascular channels lined with thick endothelial cells; it may be associated with disseminated hemangiomatosis, and death often occurs as the result of congestive heart failure.

malignant h.  hemangiosarcoma.

vertebral h.  a benign vascular tumor of the spine, seen primarily in middle-aged adults; usually asymptomatic, but in time it may expand or hemorrhage and compress the spinal canal and cord.

hemangioendotheliosarcoma (he·man·gio·en·do·the·lio·sar·co·ma) (he-man”je-o-en”do-the”le-o-sahr-ko´mə)  hemangiosarcoma.

hemangiofibroma (he·man·gio·fi·bro·ma) (he-man”je-o-fi-bro´mə) [hemangio- + fibroma]  a hemangioma containing fibrous tissue.

hemangioma (he·man·gi·o·ma) (he-man”je-o´mə) [hem- + angioma]  1. an extremely common benign tumor, occurring most commonly in infancy and childhood, made up of newly formed blood vessels, and resulting from malformation of angioblastic tissue of fetal life. There are two main types: capillary and cavernous.  2. a general term denoting a benign or malignant vascular tumor that resembles the classic type of hemangioma but occurs at any age. Cf. angioma and lymphangioma.

ameloblastic h.  hemangioameloblastoma.

capillary h.  1. the most common type of hemangioma; most are composed of closely packed aggregations of capillaries separated by scant connective stroma, which for the most part conform to the caliber of normal capillaries. According to one classification, strawberry h., nevus flammeus, cherry angioma, and pyogenic granuloma are all types of capillary hemangiomas. Cf. cavernous h. and vascular nevus.  2. strawberry h.

cavernous h.  a vascular tumor preponderantly composed of large dilated blood vessels, often containing large amounts of blood, occurring in the skin, subcutaneously, or both, and also in many viscera, particularly the liver, spleen, pancreas, and sometimes the brain. Most present in early life but are usually not present at birth. The typical superficial lesions are bright to dark red in color; deep lesions have a blue color. Called also angioma cavernosum and strawberry mark or nevus. See also vascular nevus, under nevus. Cf. capillary h.

Cavernous hemangioma.


Cavernous hemangioma.

sclerosing h.  a form of benign fibrous histiocytoma characterized not only by histiocytic and fibroblastic elements but also by numerous blood vessels and hemosiderin deposits. It is sometimes considered synonymous with or a variant of dermatofibroma.

h. sim´plex  strawberry h.

strawberry h.  1. a firm red, dome-shaped hemangioma sharply demarcated from surrounding skin, usually on the head and neck, which grows rapidly and generally undergoes regression and involution without scarring. It is caused by proliferation of immature capillary vessels in active stroma, and is usually present at birth or within the first 2 or 3 months of life. See also capillary h. and vascular nevus. Called also h. simplex, strawberry mark, and strawberry nevus.  2. vascular nevus.

venous h.  a type of cavernous hemangioma in which the dilated vessels have thick, fibrous walls.

hemangiomatosis (he·man·gio·ma·to·sis) (he-man”je-o-mə-to´sis)  a condition in which multiple hemangiomas are developed.

hemangiopericyte (he·man·gio·peri·cyte) (he-man”je-o-per´ĭ-sīt)  pericyte.

hemangiopericytoma (he·man·gio·peri·cy·to·ma) (he-man”je-o-per”ĭ-si-to´mə) [hemangiopericyte + -oma]  a tumor composed of spindle cells with a rich vascular network, which apparently arises from pericytes. It may be benign or malignant and usually occurs in the lower extremities or retroperitoneum.

h. of kidney  juxtaglomerular cell tumor.

hemangiosarcoma (he·man·gio·sar·co·ma) (he-man”je-o-sahr-ko´mə) [hemangio- + sarcoma]  a rare malignant tumor of vascular origin, formed by proliferation of endothelial tissue lining irregular vascular channels; it usually occurs in the skin, soft tissues, breast, or liver. Called also angiosarcoma and malignant hemangioendothelioma. See also lymphangiosarcoma.

hemapheic (he·ma·phe·ic) (he”mə-fe´ik)  pertaining to or characterized by hemaphein.

hemaphein (he·ma·phe·in) (he´mə-fēn”) [hema- + Gr. phaios dusky, gray]  a brown coloring matter of the blood and urine.

hemapheism (he·ma·phe·ism) (he”mə-fe´iz-əm)  the presence of hemaphein in the urine.

hemapheresis (he·ma·phe·re·sis) (he”mə-fə-re´sis) [hem- + apheresis]  apheresis.

hemapoiesis (he·ma·poi·e·sis) (he”mə-poi-e´sis) [hema- + -poiesis]  hematopoiesis.

hemapoietic (he·ma·poi·et·ic) (he”mə-poi-et´ik)  hematopoietic.

hemapophysis (he·ma·poph·y·sis) (he”mə-pof´ə-sis) [hem- + apophysis]  a costal cartilage regarded as an apophysis of the hemal spine.

hemarthros (he·mar·thros) (he-mahr´thros)  hemarthrosis.

hemarthrosis (he·mar·thro·sis) (he”mahr-thro´sis) [hem- + arthrosis]  extravasation of blood into a joint or its synovial cavity.

hemastrontium (he·ma·stron·ti·um) (he”mə-stron´she-əm)  a tissue stain prepared by adding strontium chloride to a solution of hematein and aluminum chloride in alcohol and citric acid.

hematal (he·ma·tal) (he´mə-təl)  hemic.

hematapostema (he·mat·apos·te·ma) (he”mat-ap”os-te´mə) [hemat- + Gr. apostēma abscess]  an abscess containing effused blood.

hematein (he·ma·te·in) (he´mə-tēn)   [NF] a brownish-red, crystalline substance derived from hematoxylin by oxidation; used as an indicator and stain.

hematemesis (he·ma·tem·e·sis) (he”mə-tem´ə-sis) [hemat- + emesis]  the vomiting of blood.

Goldstein's h.  hematemesis due to bleeding telangiectases in the stomach.

hematencephalon (he·mat·en·ceph·a·lon) (he”mat-, hem”at-en-sef´ə-lon) [hemat- + encephalon]  cerebral hemorrhage.

hematherapy (he·ma·ther·a·py) (he”mə-ther´ə-pe)  hemotherapy.

hemathermal (he·ma·ther·mal) (he”mə-thər´məl)  homeothermic.

hemathermous (he·ma·ther·mous) (he”mə-thər´məs)  homeothermic.

hemathorax (he·ma·tho·rax) (he”mə-thor´aks)  hemothorax.

hematic (he·mat·ic) (he-mat´ik)  1. hemic.  2. hematinic.

hematidrosis (he·ma·tid·ro·sis) (he”mə-, hem”ə-tid-ro´sis) [hemat- + Gr. hidrōsis sweating]  the excretion of bloody sweat. Called also hematohidrosis.

hematimeter (he·ma·tim·e·ter) (he”mə-, hem”ə-tim´ə-tər)  hemacytometer.

hematin (he·ma·tin) (he´mə-tin)  1. a porphyrin chelate of iron (III) formed by the oxidation of free heme; the hydroxide of heme. It stimulates the synthesis of globin and inhibits the synthesis of porphyrin by inactivation of 5-aminolevulinate synthase and is a component of the cytochromes and peroxidases. Hematin derived synthetically from hemin is used as a reagent.  2. hemin (def. 1).

hematinemia (he·ma·tin·emia) (he”mə-, hem”ə-tĭ-ne´me-ə)  the presence of hematin (heme) in the blood.

hematinic (he·ma·tin·ic) (he”mə-tin´ik)  1. pertaining to hematin.  2. an agent that increases the hemoglobin level and the number of erythrocytes in the blood.

hematinometer (he·ma·tin·om·e·ter) (he”mə-, hem”ə-tin-om´ə-tər)  old term for hemoglobinometer.

hematinuria (he·ma·tin·uria) (he”mə-tĭ-nu´re-ə)  the presence of hematin in the urine, seen in hemoglobinuria.

hematite (he·ma·tite) (he´mə-tīt)  a mineral made up of ferric oxide with a small amount of silica; inhalation of its dust can cause hematite pneumoconiosis.

hemat(o)- (hemat(o)-) [Gr. haima, gen. haimatos blood]  a combining form denoting relationship to the blood. Also, haemat(o)-.

hematobilia (he·ma·to·bil·ia) (he”mə-to-, hem”ə-to-bil´e-ah)  hemobilia.

hematoblast (he·ma·to·blast) (he´mə-to-, he-mat´o-blast”)  blast cell (def. 2).

hematocele (he·ma·to·cele) (he´mə-to-, hem´ə-to-sēl”) [hemato- + -cele1]  an effusion of blood into a cavity, such as in the tunica vaginalis testis.

parametric h. ,  pelvic h. ,  retrouterine h.  swelling caused by effusion of blood into the pouch of Douglas.

scrotal h.  effusion of blood into the tissues of the scrotum.

hematocelia (he·ma·to·ce·lia) (he”mə-to-, hem”ə-to-se´le-ə)  hematocoelia.

hematocephalus (he·ma·to·ceph·a·lus) (he”mə-to-, hem”ə-to-sef´ə-ləs) [hemato- + -cephalus]  a fetus born with its head distended with blood.

hematochezia (he·ma·to·che·zia) (he”mə-to-, hem”ə-to-ke´ze-ə) [hemato- + Gr. chezein to defecate]  the passage of bloody feces.

hematochlorin (he·ma·to·chlo·rin) (he”mə-to-, hem”ə-to-klo´rin) [hemato- + Gr. chlōros green]  a green coloring matter occurring in the placenta and derived from hemoglobin.

hematochromatosis (he·ma·to·chro·ma·to·sis) (he”mə-to-, hem”ə-to-kro”mə-to´sis) [hemato- + chromato- + -sis]  1. staining of tissues with blood pigment.  2. hemochromatosis.

hematochyluria (he·ma·to·chy·lu·ria) (he”mə-to-, hem”ə-to-ki-lu´re-ə) [hemato- + chyluria]  the discharge of blood and chyle with the urine, a symptom of filariasis.

hematocoelia (he·ma·to·coe·lia) (he”mə-to-, hem”ə-to-se´le-ə) [hemato- + coel- + -ia]  effusion of blood into the peritoneal cavity.

hematocolpometra (he·ma·to·col·po·me·tra) (he”mə-to-, hem”ə-to-kol”po-me´trə) [hemato- + colpo- + metra]  accumulation of menstrual blood in the vagina and uterus.

hematocolpos (he·ma·to·col·pos) (he”mə-to-, hem”ə-to-kol´pəs) [hemato- + Gr. kolpos vagina]  an accumulation of menstrual blood in the vagina.

hematocrit (he·mat·o·crit) (Hct) (he-mat´ə-krit) [hemato- + Gr. krinein to separate]  1. the proportion of the volume of a blood sample that is red blood cells (packed red blood cells), measured in mL per dL of whole blood or as a per cent.  2. former name for a tube or other apparatus used in making this calculation, such as the Wintrobe hematocrit tube.

large vessel h.  the hematocrit of blood from a large vessel, usually a vein; cf. total body h.

total body h. ,  whole body h.  the average hematocrit of the whole body, as determined by tracer dilution methods; it is normally about 0.92 times the large vessel hematocrit.

hematocryal (he·ma·toc·ry·al) (he”mə-, hem”ə-tok´re-əl) [hemato- + cryo- + -al1]  poikilothermic.

hematocyanin (he·ma·to·cy·a·nin) (he”mə-to-, hem”ə-to-si´ə-nin) [hemato- + Gr. kyanos blue]  hemocyanin.

hematocyst (he·ma·to·cyst) (he´mə-to-, he-mat´o-sist”) [hemato- + cyst]  an effusion of blood into the bladder or into a cyst.

hematocystis (he·ma·to·cys·tis) (he”mə-to-, hem”ə-to-sis´tis)  hematocyst.

hematocyte (he·ma·to·cyte) (he´mə-to-, he-mat´o-sīt”)  blood cell.

hematocytoblast (he·ma·to·cy·to·blast) (he”mə-to-, hem”ə-to-si´to-blast)  blast cell (def. 2).

hematocytolysis (he·ma·to·cy·tol·y·sis) (he”mə-to-, hem”ə-to-si-tol´ĭ-sis)  hemolysis.

hematocytometer (he·ma·to·cy·tom·e·ter) (he”mə-to-, hem”ə-to-si-tom´ə-tər)  hemacytometer.

hematocytopenia (he·ma·to·cy·to·pe·nia) (he”mə-to-, hem”ə-to-si”to-pe´ne-ə) [hematocyte + -penia]  cytopenia.

hematocyturia (he·ma·to·cy·tu·ria) (he”mə-to-, hem”ə-to-si-tu´re-ə)  hematuria.

hematoencephalic (he·ma·to·en·ce·phal·ic) (he”mə-to-, hem”ə-to-en”sə-fal´ik) [hemato- + encephalic]  pertaining to the blood and the brain.

hematogenesis (he·ma·to·gen·e·sis) (he”mə-to-, hem”ə-to-jen´ə-sis) [hemato- + genesis]  hematopoiesis.

hematogenic (he·ma·to·gen·ic) (he”mə-to-, he-mat”o-jen´ik)  1. hematopoietic.  2. hematogenous.

hematogenous (he·ma·tog·e·nous) (he”mə-toj´ĕ-nus)  1. produced by or derived from the blood.  2. disseminated by the circulation or through the blood stream.

hematogone (he·ma·to·gone) (he´mə-to-, he-mat´o-gōn)  old name for blast cell (def. 2).

hematohidrosis (he·ma·to·hid·ro·sis) (he´mə-to-, hem”ə-to-hid-ro´sis)  hematidrosis.

hematohistioblast (he·ma·to·his·tio·blast) (he”mə-to-, hem”ə-to-his´te-o-blast)  old name for blast cell (def. 2).

hematohyaloid (he·ma·to·hy·a·loid) (he”mə-to-, hem”ə-to-hi´ə-loid) [hemato- + hyaloid]  pertaining to a thrombus that has undergone hyaline degeneration.

hematoid (he·ma·toid) (he´mə-toid) [hemato- + -oid]  resembling blood.

hematoidin (he·ma·toid·in) (he-mə-toid´in)  a yellow-brown or red pigment, apparently chemically identical with bilirubin but with a different site of origin, formed locally in the tissues from hemoglobin, particularly under conditions of reduced oxygen tension.

hematokolpos (he·ma·to·kol·pos) (he”mə-to-, hem”ə-to-kol´pəs)  hematocolpos.

hematologist (he·ma·tol·o·gist) (he”mə-tol´ə-jist)  a specialist in hematology.

hematology (he·ma·tol·o·gy) (he”mə-tol´ə-je) [hemato- + -logy]  the branch of medical science that deals with the blood and blood-forming tissues.

hematolymphangioma (he·ma·to·lymph·an·gi·o·ma) (he”mə-to-, hem”ə-to-lim”fan-je-o´mə) [hemato- + lymph- + angioma]  a benign tumor composed of blood vessels and lymph vessels. Called also hemolymphangioma.

hematolysis (he·ma·tol·y·sis) (he”mə-tol´ə-sis)  hemolysis.

hematolytic (he·ma·to·lyt·ic) (he”mə-to-lit´ik)  hemolytic.

hematoma (he·ma·to·ma) (he”mə-to´mə) [hemato- + -oma]  a localized collection of blood, usually clotted, in an organ, space, or tissue, usually due to a break in the wall of a blood vessel.

aneurysmal h.  false aneurysm.

auricular h. ,  h. au´ris  hematoma of the perichondrium of the auricle, a common precursor of cauliflower ear.

dissecting h.  dissecting aneurysm.

epidural h.  accumulation of blood in the epidural space, due to damage to and leakage of blood from the middle meningeal artery, producing compression of the dura mater and thus compression of the brain. Unless evacuated, it may result in herniation through the tentorium, and death.

parenchymatous h.  a mass of blood within the brain tissue itself, usually from rupture of an artery or vein within the brain.

pelvic h.  a collection of blood in the pelvic soft tissue.

perianal h.  a hematoma under the perianal skin, caused by rupture of a subcutaneous vessel, the blood being kept localized by fibroelastic septa and causing much pain.

perinephric h. ,  perirenal h.  one resulting from a perirenal hemorrhage (see under hemorrhage).

pulsating h.  pseudoaneurysm.

retroperitoneal h.  one resulting from a retroperitoneal hemorrhage (see under hemorrhage).

retrouterine h.  an effusion of blood into the retrouterine connective tissue.

subcapsular h.  one in the subcapsular space of the kidney; it may be due to a tumor, trauma, vasculitis, renal infarction, or other disease process.

subdural h.  accumulation of blood in the subdural space. In the severe acute form, both blood and cerebrospinal fluid enter the space as a result of laceration of the brain and a tear in the arachnoid, adding subdural compression to the direct injury to the brain. In the chronic form, only blood effuses into the subdural space as a result of rupture of the bridging veins, usually due to closed head injury. The effusion is a gradual process resulting, weeks after the injury, in headache and progressive focal signs that reflect the location of the mass.

Acute focal subdural hematoma of the left frontal area of a six-month-old infant. The layering of subdural blood is due to rapid collection and consists of newly clotted blood and fresh hemorrhage.


Acute focal subdural hematoma of the left frontal area of a six-month-old infant. The layering of subdural blood is due to rapid collection and consists of newly clotted blood and fresh hemorrhage.

subepithelial h. of renal pelvis  a hematoma from bleeding in the subepithelial tissue of the renal pelvis, usually the result of a coagulopathy such as in hemophilia, thrombocytopenia, or anticoagulant therapy. Called also Antopol-Goldman lesion.

subungual h.  an accumulation of blood under the nail plate.

hematomanometer (he·ma·to·ma·nom·e·ter) (he”mə-to-, hem”ə-to-mə-nom´ə-tər)  sphygmomanometer.

hematomediastinum (he·ma·to·me·di·as·ti·num) (he”mə-to-, hem”ə-to-me”de-əs-ti´nəm) [hemato- + mediastinum]  hemomediastinum.

hematometer (he·ma·tom·e·ter) (he”mə-, hem”ə-tom´ə-tər)  old term for hemoglobinometer.

hematometra (he·ma·to·me·tra) (he”mə-to-, hem”ə-to-me´trə) [hemato- + metra]  an accumulation of blood in the uterus.

hematometry (he·ma·tom·e·try) (he”mə-tom´ə-tre) [hemato- + -metry]  measurement of various parameters of the blood, such as the complete blood count (see under count).

hematomyelia (he·ma·to·my·elia) (he”mə-to-, hem”ə-to-mi-e´le-ə) [hemato- + myel- + -ia]  hemorrhage into the spinal cord, usually confined to the gray substance, most often due to trauma but also seen in arteriovenous malformations; marked by the sudden onset of flaccid paralysis with sensory disturbances.

hematomyelitis (he·ma·to·my·eli·tis) (he”mə-to-, hem”ə-to-mi”ə-li´tis) [hemato- + myelitis]  acute myelitis with bloody effusion within the spinal cord.

hematomyelopore (he·ma·to·my·elo·pore) (he”mə-to-, hem”ə-to-mi´əl-o-por”) [hemato- + myelo- + pore]  a disease marked by the formation of canals in the spinal cord, due to hemorrhage.

hematonephrosis (he·ma·to·ne·phro·sis) (he”mə-to-, hem”ə-to-nə-fro´sis)  hemonephrosis.

hematopathology (he·ma·to·pa·thol·o·gy) (he”mə-to-, hem”ə-to-pə-thol´ə-je)  hemopathology.

hematopenia (he·ma·to·pe·nia) (he”mə-to-, hem”ə-to-pe´ne-ə) [hemato- + -penia]  deficiency of blood; see also anemia.

hematopericardium (he·ma·to·peri·car·di·um) (he”mə-to-, hem”ə-to-per”ĭ-kahr´de-əm)  hemopericardium.

hematoperitoneum (he·ma·to·peri·to·ne·um) (he”mə-to-, hem”ə-to-per”ĭ-to-ne´əm)  hemoperitoneum.

hematophage (he·ma·to·phage) (he´mə-to-, he´mə-to-fāj)  hemophagocyte.

hematophagia (he·ma·to·pha·gia) (he”mə-to-, hem”ə-to-fa´jə)  1. blood drinking.  2. subsisting on the blood of another animal.

hematophagocyte (he·ma·to·phago·cyte) (he”mə-to-, hem”ə-to-fag´o-sīt)  hemophagocyte.

hematophagous (he·ma·toph·a·gous) (he”mə-, hem”ə-tof´ə-gəs) [hemato- + phag- + -ous]  characterized by hematophagia.

hematophagy (he·ma·toph·a·gy) (he”mə-, hem”ə-tof´ə-je)  hematophagia.

hematophilia (he·ma·to·phil·ia) (he”mə-to-, hem”ə-to-fil´e-ə)  hemophilia.

hematophobia (he·ma·to·pho·bia) (he”mə-to-, hem”ə-to-fo´be-ə)  hemophobia.

hematoplastic (he·ma·to·plas·tic) (he”mə-to-, hem”ə-to-plas´tik) [hemato- + plastic]  hematopoietic.

hematopoiesis (he·ma·to·poi·e·sis) (he”mə-to-, hem”ə-to-poi-e´sis) [hemato- + -poiesis]  the formation and development of blood cells. In the embryo and fetus it takes place in a variety of sites including the liver, spleen, thymus, lymph nodes, and bone marrow; from birth throughout the rest of life it is mainly in the bone marrow with a small amount occurring in lymph nodes. See also erythropoiesis, leukopoiesis, and thrombocytopoiesis. Called also hematogenesis, hemogenesis, and hemopoiesis.

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Hematopoiesis. CFU-GEMM: colony-forming unit–granulocyte, erythrocyte, monocyte, megakaryocyte. BFU-E: burst-forming unit–erythroid. CFU-E: colony-forming unit–erythroid. CFU-MEG: colony-forming unit–megakaryocytic. CFU-GM: colony-forming unit–granuloctye-macrophage. CFU-EO: colony-forming unit–eosinophilic. CFU-BASO: colony-forming unit–basophilic. CFU-G: colony-forming unit–granulocytic. CFU-M: colony-forming unit–macrophage.

cyclic h.  see under neutropenia.

extramedullary h.  the formation and development of blood cells outside the bone marrow, as in the spleen, liver, and lymph nodes.

hematopoietic (he·ma·to·poi·et·ic) (he”mə-to-, hem”ə-to-poi-et´ik)  1. pertaining to or effecting hematopoiesis; called also hemapoietic, hematogenic, hematoplastic, hemogenic, and hemopoietic.  2. an agent that promotes hematopoiesis.

hematopoietin (he·ma·to·poi·e·tin) (he”mə-to-, hem”ə-to-poi´ə-tin)  erythropoietin.

hematoporphyrin (he·ma·to·por·phy·rin) (he”mə-to-, hem”ə-to-por´fə-rin)  a dark red to purple pigment, a porphyrin (q.v.) in which two pyrrole rings have one methyl and one propionate side chain and the other two pyrrole rings have one methyl and one 1-hydroxyethyl side chain.

Hematopota (He·ma·top·o·ta) (he”mə-, hem”ə-top´o-tə)  Haematopota.

hematorrhachis (he·ma·tor·rha·chis) (he”mə-to-, hem”ə-tor´ə-kis) [hemato- + Gr. rhachis spine]  hematomyelia.

hematosalpinx (he·ma·to·sal·pinx) (he”mə-to-, hem”ə-to-sal´pinks)  an accumulation of blood in the uterine tube.

hematosepsis (he·ma·to·sep·sis) (he”mə-to-, hem”ə-to-sep´sis)  septicemia.

hematospectroscope (he·ma·to·spec·tro·scope) (he”mə-to-, hem”ə-to-spek´tro-skōp) [hemato- + spectroscope]  a spectroscope for examining thin layers of blood.

hematospectroscopy (he·ma·to·spec·tros·co·py) (he”mə-to-, hem”ə-to-spek-tros´ko-pe) [hemato- + spectroscopy]  spectroscopic examination of the blood.

hematospermatocele (he·ma·to·sper·mato·cele) (he”mə-to-, hem”ə-to-spər-mat´o-sēl) [hemato- + spermato- + -cele1]  a spermatocele containing blood.

hematospermia (he·ma·to·sper·mia) (he”mə-to-, hem”ə-to-spər´me-ə)  hemospermia.

hematostatic (he·ma·to·stat·ic) (he”mə-to-, hem”ə-to-stat´ik) [hemato- + -static]  hemostatic (def. 3).

hematosteon (he·ma·tos·te·on) (he”mə-, hem”ə-tos´te-on) [hemat- + osteon]  hemorrhage into the medullary cavity of a bone.

hematotherapy (he·ma·to·ther·a·py) (he”mə-to-, hem”ə-to-ther´ə-pe)  hemotherapy.

hematothermal (he·ma·to·ther·mal) (he”mə-to-, hem”ə-to-thər´məl) [hemato- + thermal]  homeothermic.

hematothorax (he·ma·to·tho·rax) (he”mə-to-, hem”ə-to-thor´aks)  hemothorax.

hematotoxic (he·ma·to·tox·ic) (he´mə-to-, hem´ə-to-tok”sik) [hemato- + toxic]  1. pertaining to hematotoxicosis.  2. poisonous to the blood and hematopoietic system.

hematotoxicosis (he·ma·to·tox·i·co·sis) (he”mə-to-, hem”ə-to-tok”sĭ-ko´sis)  toxic damage to the hematopoietic system.

hematotrachelos (he·ma·to·tra·che·los) (he”mə-to-, hem”ə-to-trə-ke´ləs) [hemato- + Gr. trachēlos neck]  distention of the cervix of the uterus with blood, owing to atresia of the external os or of the vagina.

hematotropic (he·ma·to·trop·ic) (he”mə-to-, hem”ə-to-trop´ik) [hemato- + -tropic]  having a special affinity for or exerting a specific effect on the blood or blood cells.

hematotympanum (he·ma·to·tym·pa·num) (he”mə-to-, hem”ə-to-tim´pə-nəm) [hemato- + tympanum]  hemotympanum.

hematoxic (he·ma·tox·ic) (he´mə-tok”sik)  hematotoxic.

hematoxylin (he·ma·tox·y·lin) (he”mə-tok´sĭ-lin)  a colorless crystalline compound obtained by extracting logwood (Haematoxylon campechianum) with ether. It may be used as an indicator with a pH range of 5–6, but is mainly used in oxidized form as a stain in microscopy. See also at Stains and Staining Methods, under stain.

alum h.  hemalum.

Delafield's h.  see at Stains and Staining Methods, under stain.

Harris h.  see at Stains and Staining Methods, under stain.

iron h.  see iron hematoxylin method, Heidenhain's iron hematoxylin stain, and Weigert's iron hematoxylin stain, all at Stains and Staining Methods, under stain.

Hematoxylon (He·ma·tox·y·lon) (he”mə-tok´sĭ-lən)  Haematoxylon.

hematozemia (he·ma·to·ze·mia) (he”mə-to-, hem”ə-to-ze´me-ə) [hemato- + Gr. zēmia loss]  a gradual loss of blood.

hematozoa (he·ma·to·zoa) (he”mə-to-, hem”ə-to-zo´ə)  plural of hematozoon.

hematozoal (he·ma·to·zo·al) (he”mə-to-, he”mə-to-zo´əl)  hematozoan (def. 1).

hematozoan (he·ma·to·zo·an) (he”mə-to-, hem”ə-to-zo´ən) [hemato- + Gr. zōon animal]  1. pertaining to or caused by animal parasites living in the host's blood. Called also hematozoal, hematozoic, and hemozoic.  2. any animal parasite living in the host's blood. Called also hematozoon and hemozoon.

hematozoic (he·ma·to·zo·ic) (he”mə-to-, hem”ə-to-zo´ik)  hematozoan (def. 1).

hematozoon (he·ma·to·zo·on) (he”mə-to-, hem”ə-to-zo´ən)  pl. hematozo´a  Hematozoan (def. 2).

hematuria (he·ma·tu·ria) (he”mə-, hem”ə-tu´re-ə) [hemat- + -uria]  blood (erythrocytes) in the urine; called also erythrocyturia.

benign familial h.  thin basement membrane nephropathy.

benign recurrent h.  hematuria that does not progress to renal insufficiency, such as that seen with IgA nephropathy.

endemic h.  urinary schistosomiasis.

enzootic bovine h.  a disease of cattle marked by passing of blood in the urine, anemia, and debilitation; it is usually due to bracken poisoning.

essential h.  hematuria for which no cause has been determined; called also primary h. and functional h.

false h.  pseudohematuria.

functional h.  essential h.

gross h.  hematuria in which redness of the urine can be seen by the naked eye; called also macroscopic h.

macroscopic h.  gross h.

microscopic h.  blood in the urine visible only with a microscope, defined as at least two or three red blood cells per high power field. Called also microhematuria.

persistent h.  hematuria present in every specimen.

primary h.  essential h.

renal h.  hematuria in which the blood comes from the kidney.

urethral h.  hematuria in which the blood comes from the urethra.

vesical h.  hematuria in which the blood comes from the bladder.

heme (heme) (hēm)  1. any quadridentate chelate of iron with the four pyrrole groups of a porphyrin, further distinguished as ferroheme or ferriheme referring to the chelates of Fe(II) and Fe(III) respectively. The four porphyrin ligands form a square-planar complex; the fifth and sixth coordination positions of the iron atom are perpendicular to the plane of the porphyrin and both may be occupied by strong field ligands, such as a nitrogen atom of a histidine residue of a protein, as in cytochromes, or only one may be so occupied, as in hemoglobin where the sixth position reversibly binds oxygen.  2. ferroheme.  3. protoheme IX, the heme of hemoglobin. See protoheme.

hemendothelioma (hem·en·do·the·li·o·ma) (hēm”en-do-the”le-o´mə)  hemangioendothelioma.

heme oxygenase (decyclizing) (heme oxy·gen·ase (de·cy·cliz·ing)) (hēm ok´sĭ-jən-ās de-si´kli-zing)   [EC 1.14.99.3] an enzyme of the oxidoreductase class that catalyzes the cleavage of heme to form biliverdin, a step in heme catabolism.

hemeralope (hem·er·al·ope) (hem´ər-əl-ōp)  a person affected with hemeralopia.

hemeralopia (hem·er·a·lo·pia) (hem”ər-ə-lo´pe-ə) [Gr. hēmera day + alaos blind + -opia]  defective vision in a bright light; called also day blindness and night sight.

Hemerocampa (Hem·ero·cam·pa) (hem”ər-o-kam´pə)  a genus of moths. H. leukostig´ma is the tussock moth, a species with white markings whose larval stage has venomous hairs that may produce severe urticaria. See also insect dermatitis, under dermatitis.

hemerythrin (hem·eryth·rin) (hēm”ə-rith´rin) [hem- + Gr. erythros red]  the coloring matter of the blood of earthworms which is contained in the plasma.

heme synthase (heme syn·thase) (hēm sin´thās)  ferrochelatase.


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