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(hel′minth″) [Gr. helmins, stem helminth-, worm] 1. A wormlike animal. 2. Any animal, either free-living or parasitic, belonging to the phyla Platyhelminthes (flatworms), Acanthocephala (spinyheaded worms), Nemathelminthes (threadworms or round-worms), or Annelida (segmented worms). SEE: illus. helminthic (helmin′thik), adj.






(hel-mĭn-thī′ă-sĭs) [helminth + -iasis] Infestation with worms.


(hel-min′thik) [helminth + -ic] 1. Pert. to worms. 2. Pert. to that which expels worms. SYN: anthelmintic; vermifugal.


(hel″mĭn-thol′ŏ-jē) [helminth + -logy] The scientific study of worms, esp. of parasitic worms. helminthologist (hel″mĭn-thol′ŏ-jist), n.


(hē″lō-dĕr′mă) Fibromas that form on the extensor surfaces of the proximal interphalangeal joints of the hands.


Heat escape lessening position.

helper T cells

SEE: cell, helper T.


A feeling of dependence, powerlessness, defenselessness, or depression, e.g., in the face of crisis or overwhelming circumstances. SEE: hopelessness; powerlessness.

learned h. A passive fatalistic behavior that one cannot influence one’s environment, or alter one’s existence. This condition may sometimes arise in people who have chronic illnesses, depression, phobias, or loss of functional independence.

hem-, hema-, hemo-

[Gr. haima, blood] Prefixes meaning blood. The variant “haem-” is used outside the U.S. SEE: hemat-.


(hē′măd) [Gr. haima, blood, + L. ad, toward] Hemal (2).


(hĕm″ăd-sorp′shŭn) The adherence of red blood cells to other cells or surfaces.

hemagglutination, hemoagglutination

(hē″mă-gloot″ĭn-ā′shŏn, hē″mō-ă-gloot″ĭn-ā′shŏn) [hem- + agglutination] The clumping of red blood cells. SEE: agglutination.


(hē″mă-gloot′ĭn-ĭn) [hem- + agglutinin] ABBR: H. 1. An antibody that induces clumping of red blood cells. SEE: agglutination; agglutinin. 2. An influenza virus protein that helps viral particles attach themselves to cells in the respiratory tract and enter these cells through their cellular membranes.

 The regular mutations of H change the pathogenicity of the influenza virus. Vaccines manufactured each year to prevent influenza are formulated to anticipate the hemagglutinin and the neuraminidase antigens of new influenza viruses that will circulate around the world in that particular year. SEE: neuraminidase.


(hē′măl) 1. Pert. to the blood or blood vessels. 2. Pert. to the ventral side of the body, in which the heart is located, as opposed to the neural or dorsal side. SYN: ...

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