search for: ic50

Hello, I was wondering if there is an R-package to automatically calculate the IC50 value (concentration of a substrance that inhibits cell growth to 50%) for some measurements. kind regards, Arne [[alternative HTML version deleted]]

Hi, I am trying to use drc package to calculate IC50 value. The ED50 calculated in some models (LL4 for example) as a response half-way between the upper and lower limit, which is the definition of the relative IC50 value. Does that mean the ED50 in drc package is IC50? How the ED function in drc package distinguish to estimate ED or IC values? Than...

Hi, I am newbie of R. I a currently using multdrc object to generate fitting curve and IC50. My 384 well format raw data contains multi dose response curves. My script goes through set of data then produce curve and ic50. Here is my sudo code: For (plateid in platelist) { Input data (plateid) as matrix Curve fitting model4logistic <- multdrc(rdata ~ ld, logDose=10) }...

Hello, We use drc to fit dose-response curves, recently we discovered that there are quite different standard error values returned for the same dataset depending on the drc-version / R-version that was used (not clear which factor is important) On R 2.9.0 using drc_1.6-3 we get an IC50 of 1.27447 and a standard error on the IC50 of 0.43540 Whereas on R 2.7.0 using drc_1.4-2 the IC50 is 1.2039e+00 and the standard error is 3.7752e-03 Normally I would use the most recent version (both R and drc library) but it seems to me that a standard error of 0.4 on a mean of 1.2 is too b...

Hello everyone, I have biological data from a competition experiment where a free ligand is titrated against the binding of a protein. Now, I would like to fit a standard on-site binding curve to this data in order to obtain the IC50 and Kd values. Unfortunately I have not been able to find a package/function which allows such a fitting and calculates the results. Does anyone know if there is a suitable package available and which function to apply? Thanks a lot. Cheers Thiemo Schreiber [[alternative HTML version deleted]...

Respected Sir/Madam, I have a question regarding calculation of LD50 (Lethal Dose) and IC50 (50% inhibitory concentration) of an antimicrobial experiment. I have used a compound isolated from a plant and observed its effect on the fungus *Fusarium oxysporum* by the food poisoning method. Solutions of the compound at concentrations of 0, 50, 100, 150, 200 and 250µg/ ml were added to ste...

...eate( res.path ) Just before calling the function that fails, I remove, if exist, the old files of the directory: file.remove( paste0( res.path, dir( res.path ) ) ) Then, I call f.texto, whose code is as follows: f.texto <- function( l, res, a ){ myfile <- res write( paste( "SAIC50. ", a, ", ", date(), sep = "" ), file = paste( res.path, myfile, sep = "" ) ) write( "----------------------------------", file = paste (res.path, myfile, sep = ""), append = T ) write( "\r\n", file = paste( res.path, myfile,...

If anyone has a list of application areas where there is extensive use of R, I'd like to hear of it. My current short list is: Bioinformatics Epidemiology Geophysics Agriculture and crop science John Maindonald Mathematical Sciences Institute, Australian National University. john.maindonald at anu.edu.au

...for fitting a distribution with density: p*g(x) + (1-p)*f(x) where g(x) is the familiar lognormal 2-parameter density and f(x) is Pareto as defined below? Here is the lengthier story: I am collaborating with a scientific colleague who has constructed a database of binding assay data, namely EC/IC50's across a wide variety of chemical entities and experimental conditions. Among other things, he has an interest in characterizing tails of the distribution. We have been studying various fields in the literature to get a sense of what density forms we should focus on. In addition to lognorm...

Hi! I want to use the DRC package in order to calculate the IC50 value of an enzyme inhibition assay. The problem is that the estimated ED50, is always out of the fitted curve. In the example below, I had a ED50 value of 2.2896, But when I predict the response level for this concentration I get a value of 45.71 instead of the expected value of 50. This is my...