| venom haemolysis | That caused by haemolytic material in the venom of various species of snakes or other venomous animals. (05 Mar 2000) |
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| black widow spider venom | Potent neurotoxin that induces catastrophic release of acetylcholine from presynaptic terminals of cholinergic chemical synapses. (18 Nov 1997) |
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| venom | <chemical> A toxic secretion in animals that is actively delivered to the target organism, either to paralyse or incapacitate or else to cause pain as a defence mechanism. Commonly include protein and peptide toxins. (12 Jan 1998) |
| Russell's viper venom | A venom used as a coagulant in the arrest of haemorrhage from accessible sites in haemophilia. (05 Mar 2000) |
| Russell's viper venom clotting time | A clotting time determination performed on citrated platelet-poor plasma using Russell's viper venom as an activating agent. This allows activation of factor X directly without the need for other coagulation factors and is used to confirm factor X defects. See: Stypven time test. (05 Mar 2000) |
| cobra venom cofactor | <enzyme> A glycine-rich, heat-labile beta-glycoprotein found in blood. It is a proactivator of complement 3 in the alternate pathway of complement activation. Factor b is converted by factor d to c3 convertase. Registry number: EC 3.4.21.47 (12 Dec 1998) |
| cobra venom factor | A component of cobra venom that renders C3 proactivator (properdin factor B) susceptible to factor D of the properdin system, leading to activation of C3 and other components of complement and lysis of unsensitised erythrocytes. (05 Mar 2000) |
| crotalid venom | <herpetology> Venoms from snakes of the subfamily crotalinae or pit vipers, found mostly in the americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and american copperhead. Their venoms contain nontoxic proteins, cardio-, haemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases a. Many of the toxins have been characterised. (12 Dec 1998) |
| direct lytic factor of cobra venom | A polypeptide of 62 residues; action on cells is similar to that of melittin in that it promotes disruption of membranes; used as an investigational antirheumatic agent. Synonym: cobra toxin, direct lytic factor of cobra venom. (05 Mar 2000) |
| kokoi venom | A potent neurotoxin found in the frog Phyllobates bicolor; it is a nonprotein compound with a molecular weight of approximately 400, and is lethal in microgram quantities. (05 Mar 2000) |
| a' haemolysis | Haemolysis observed infrequently in blood agar cultures of occasional strains of streptococci; the zone of haemolysis about the colony is not as clear, or wide, or distinctly outlined as it is in b haemolysis; there are a few apparently intact erythrocytes throughout the zone, but they are more numerous in the immediate vicinity of the colony, and there is no discoloration as there is in a haemolysis; the unique feature is that the zone becomes wider, i.e., the process is stimulated, when the culture is incubated at refrigerator temperatures (not true for b haemolysis); some strains of streptococci that are a'-haemolytic on horse blood agar cause typical a haemolysis on rabbit blood agar. (05 Mar 2000) |
| b haemolysis | Complete or "true" haemolysis observed in blood agar cultures of various bacteria, especially haemolytic streptococci and staphylococci; virtually all of the erythrocytes are destroyed in a relatively wide, regularly circumscribed, circular zone about the colony, thereby resulting in a clear "halo" of transparent agar; the zone of haemolysis is frequently much wider than the diameter of the colony; the degree of change varies with species of erythrocytes, e.g., those of sheep and rabbits are usually more easily haemolyzed than those of man, and so on; the haemolysin acts extracellularly (in the absence of the bacterial cells) and may be quantitatively estimated by means of tube-dilution tests of a bacteria-free filtrate (containing the haemolytic substance) with a suspension of erythrocytes. (05 Mar 2000) |
| biologic haemolysis | Haemolysis caused by agents elaborated by various animal and plant forms. (05 Mar 2000) |
| g haemolysis | A term sometimes used to indicate that there is no haemolysis in relation to bacterial colonies in or on blood agar; thus, nonhemolytic organisms may be referred to as producing g haemolysis. (05 Mar 2000) |
| viridans haemolysis | See: a' haemolysis. (05 Mar 2000) |
| phenylhydrazine haemolysis | An in vitro test for G6PD deficiency; haemolysis resulting from in vitro addition of phenylhydrazine to blood with red cells which are deficient in glucose-6-phosphate dehydrogenase (G6PD), with the appearance of Heinz-Ehrlich bodies. (05 Mar 2000) |