220-Dictionary of Pharmaceutical Medicine, 2nd Edition-Gerhard Nahler Annette Mollet-3211898352-S

114micby chemicals; → see also aneugen, clastogen, genotoxicity,toxicity tests.microRNA Short RNAs of about 22 nucleotides that negatively regulatetarget gene expression at the post-transcriptional level; theyare implicated in the regulation of biological processes such as cellgrowth, differentiation and apoptosis; deregulation is involved in anumber of diseases such as cancer and inflammatory diseases.migration study Study design in which disease occurrence in individualswho migrate to or from an area is compared with diseaseoccurrence in individuals who do not migrate, in an attempt toseparate genetic susceptibility from an environmental risk factor;since migrants are frequently different from those who stay in anarea, and the number of individuals migrating who develop thedisease is usually small, such studies are rarely informative; → seealso risk.minimal clinically important difference (MCID) → see delta value.minimal bactericidal concentration (MBC) Minimal concentration(usually in mg/l) of an antibiotic which kills an organism; → seealso minimal inhibitory concentration.minimal inhibitory concentration (MIC) Minimal concentration(usually in mg/l) of an antibiotic inhibiting growth of an organism;→ see also minimal bactericidal concentration.minimal risk Risks or harm anticipated in the proposed research thatare not greater, considering probability and magnitude, than thoseordinarily encountered in daily life or during the performance ofroutine physical or psychological examinations or tests.minimal toxic dose (MTD) Dose which just shows toxic effects;→ see noel, toxicity tests.minimization Method in which patients are assigned to treatmentgroups so that the differences in known prognostic variables areminimized (“matched pairs”); e.g. in m. for the factors age (≤50or >50), duration of disease (≤1 or >1 year) and pretreatment (yesor no) each patient appears once for each factor; then one addstogether the number of patients in the corresponding three rowsfor treatment A as well as for B and assigns a new patient so thatthe difference between A and B is minimized; sometimes, e.g. insingle centre trials, it may however be useful to introduce someelement of chance by assigning the treatment with the smallest totalsum with a probability