How is GI50 calculated?
The NCI renamed the IC50 value, the concentration that causes 50% growth inhibition, the GI50 value to emphasize the correction for the cell count at time zero; thus, GI50 is the concentration of test drug where 100 × (T – T0)/(C – T0) = 50 (3, 9).
What is GI50 value?
GI50 is the concentration for 50% of maximal inhibition of cell proliferation, and should be used for cytostatic (as opposed to cytotoxic) agents. ED50 (or EC50) is the Dose (or Concentration) causing 50% of maximum effect for any measured biological effect of interest.
What is the principle of SRB assay?
Its principle is based on the ability of the protein dye sulforhodamine B to bind electrostatically and pH dependent on protein basic amino acid residues of trichloroacetic acid-fixed cells.
Do apoptotic cells release LDH?
Lactate dehydrogenase, or LDH, is a stable, soluble cytosolic enzyme that is present in most eukaryotic cells. When the plasma membrane is damaged, LDH releases into the cell culture upon necrosis (accidental cell death) or apoptosis (programmed cell death).
Why is EC50 used?
It is simply the concentration of agonist required to provoke a response halfway between the baseline and maximum responses. Because the EC50 defines the location of the dose-response curve for a particular drug, it is the most commonly used measure of an agonist’s potency.
When do you use EC50?
IC50 is used in case there is an assay in which there is a decline in activity; i.e. the higher the conc of the inhibitor, the higher is the inhibition (negative activity). EC50 is used for substances that complement a system, the higher the conc, the higher is the (positive) activity.
What is the difference between IC50 and GI50?
The NCI renamed the IC50 value, the concentration that causes 50% growth inhibition, the GI50 value to emphasize the correction for the cell count at time zero; thus, GI50 is the concentration of test drug where 100 × (T – T0)/(C – T0) = 50 (3, 9).
What is the best way to search the GI50 data?
The main Oracle database table that contains the GI50 data of the in vitro anticancer screen was searched by Structured Query language (SQL) (the search language for Oracle and many other relational database management systems, SQL). The resulting file was output as an SAS data set ready for further processing by SAS programs.
How are deltas generated from the GI50 data?
The positive and negative values, called deltas, are generated from the GI50 data (or TGI or LC50 data) by a three-step calculation. The GI50 value for each cell line tested against a test compound is converted to its log10 GI50 value. These log10 GI50 values are averaged. Each log10 GI50 value is subtracted from the average to create the delta.
What is the hiconc value for the GI50?
For mean graph (see the discussion later) and COMPARE purposes, the value assumed for the GI50 in such a case is the highest concentration tested (HICONC). Similar approximations are made when the GI50 cannot be calculated because the GI50PRCNT does not go as high as 50 or above (3% of total).