| HPDR | hypophosphatemic D-resistant rickets |
|---|---|
| HR | heart rate; hemorrhagic retinopathy; high resolution; higher rate; histamine receptor; hormonal resp... |
| HVDRR | hypocalcemic vitamin D-resistant rickets |
| PDDR | pseudovitamin D-dependent rickets |
| SLHR | sex-linked hypophosphatemic rickets |
| refractory cast | A cast made of material that will withstand the high temperatures of metal casting or soldering without disintegrating. Synonym: investment cast. (05 Mar 2000) |
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| refractory flask | A metal tube in which a refractory mold is made for casting metal dental restorations or appliances. Synonym: casting flask, casting ring. (05 Mar 2000) |
| refractory lining | A lining, usually of ceramic, capable of resisting and maintaining high temperatures. (05 Dec 1998) |
| refractory period | <neurology, physiology> most commonly used in reference to the interval (typically 1ms) after the passage of an action potential during which an axon is incapable of responding to another. This is caused by inactivation of the sodium channels after opening. The maximum frequency at which neurons can fire is thus limited to a few hundred Hertz. An analogous refractory period occurs in individuals of Dictyostelium discoideum, which are insensitive to extracellular cyclic AMP immediately after a pulse of cAMP has been secreted. The term can be applied to any system where a similar insensitive period follows stimulation. (18 Nov 1997) |
| refractory period of electronic pacemaker | The time required to restore full sensitivity after detecting cardiac activity or delivering a pacing impulse. (05 Mar 2000) |
| refractory period, psychological | A delayed response interval occurring when two stimuli are presented in close succession. (12 Dec 1998) |
| refractory state | Subnormal excitability immediately following a response to previous excitation; the state is divided into absolute and relative phases. (05 Mar 2000) |
| relative refractory period | The period between the effective refractory period and the end of the refractory period; fibres then respond only to high intensity stimuli and the impulses conduct more slowly than normally. (05 Mar 2000) |
| primary refractory anaemia | Any of a group of anaemic conditions in which there is persistent, frequently advanced anaemia that is not successfully treated by any means except blood transfusions, and that is not associated with another primary disease. (05 Mar 2000) |
| secondary refractory anaemia | Any persistent anaemia that is successfully treated only by blood transfusions, and that is associated with another condition. (05 Mar 2000) |
| effective refractory period | The period during which impulses may appear but are too weak to be conducted; the longest interval between adequate stimuli, falling just short of the time necessary to allow a propagated response to be evoked in a tissue by the second stimulus; it differs from the functional refractory period in that it is a measure of stimulus interval rather than response interval of time. (05 Mar 2000) |
| total refractory period | The absolute refractory period plus the relative refractory period. (05 Mar 2000) |
| functional refractory period | The minimum interval possible between successive responses to stimulation of a tissue. (05 Mar 2000) |