Cytoprotection is defined as an ability of pharmacologic agents, originally PGs, to prevent gastric and intestinal mucosal injury produced by a variety of ulcerogenic agents (eg, aspirin, indomethacin, bile acids) and by necrotizing agents (eg, boiling water, absolute alcohol, 0.6 mol/L HCl, 0.2 mol/L NaOH).
Definition of systematic error. : an error that is not determined by chance but is introduced by an inaccuracy (as of observation or measurement) inherent in the system.
1 Bias and Confounding. . 2  Bias. is a systematic error in a study and cannot be fixed. . 3  Confounding may lead to errors in the conclusion of a study, but, when confounding variables are known, the effect may. be fixed.