| reaction of degeneration | The electrical reaction in a degenerated nerve and the muscles supplied by it; characterised by absence of response to both galvanic and faradic stimulus in the nerve and to faradic stimulus in the muscles; the muscles may still respond to galvanic stimulation, but the cathodal closing contraction is greater than the anodal closing contraction, the reverse of normal. (05 Mar 2000) |
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| reaction of identity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| reaction of nonidentity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| reaction of partial identity | See: gel diffusion precipitin tests in two dimensions. (05 Mar 2000) |
| reaction quotient | <chemistry> A constant represented by the symbol Q which is defined as the product of the concentrations of the products, each raised to the power that corresponds to its coefficient in the balanced equation, divided by the product of the concentrations of reactants, each raised to the power that corresponds to its coefficient in the balanced equation (see the equation in the equations page). at equilibrium conditions Q=K, the equilibrium constant. (09 Jan 1998) |
| reaction time | The time from the onset of a stimulus until the organism responds. (12 Dec 1998) |
| Marchi's reaction | Failure of the myelin sheath of a nerve to blacken when submitted to the action of osmic acid. (05 Mar 2000) |
| Gerhardt's reaction | In fresh urine a red colour develops upon addition of FeCl3; no colour develops if the urine has first been boiled; this test has low specificity and sensitivity. Synonym: Gerhardt's reaction. (05 Mar 2000) |
| Carr-Price reaction | The reaction of antimony trichloride with vitamin A to yield a brilliant blue colour; this reaction forms the basis of several quantitative techniques for the determination of vitamin A. (05 Mar 2000) |
| redox reaction | <chemistry> A reaction in which one or more electrons are transferred. (09 Jan 1998) |
| catalatic reaction | Decomposition of H2O2 to O2 and H2O, as in the action of catalase; analogous to peroxidase reaction. (05 Mar 2000) |
| catastrophic reaction | The disorganised behaviour that is the response to a severe shock or threatening situation with which the person cannot cope. (05 Mar 2000) |
| Mazzotti reaction | A test for onchocerciasis using an oral test dose of diethylcarbamazine (50 or 100 mg), resulting in the appearance of an acute rash in 2 to 24 hours from death of microfilariae in the skin. Synonym: Mazzotti reaction. (05 Mar 2000) |
| Paul's reaction | Pus is rubbed into a scarification on a rabbit's eye; if the pus is from a variolous or vaccinal pustule a condition of epitheliosis develops in from 36 to 48 hours; the sputum of a smallpox patient is said to cause the same reaction. Synonym: Paul's test. (05 Mar 2000) |
| cell-mediated reaction | Immunological reaction of the delayed type, involving chiefly T lymphocytes, important in host defense against infection, in autoimmune diseases, and in transplant rejection. See: skin test. (05 Mar 2000) |