what does polymerase chain reaction (pcr) inhibited means?

Answer 1

PCR is a process by which many copies are made of a stretch of nucleic acid. You reqiure for a succesful reaction: the template (original piece you're going to copy); the primers (short pieces of DNA which match sequences at each end of the area you want to copy - these will be your starting points for the copy, and the vast majority of the copies will run from each end of the primers and include everything in between); nucleotides to build the copies from; a salt buffer that minics the internal solution of the cell where DNA replication naturally occurs; and a DNA polymerase - the enzyme that builds the copies. The thing is, PCR tends to have certain conditions under which it works well, and these conditions can be both very specific and very limited. Every combination of template and primers has a particular set of 'ideal' conditions, and these can sometimes be very different from the 'average' set of conditions. So, PCR can be a pain to get working at the best of times! Now, to answer your question - inhibition of a PCR can happen if something is present that interferes with the proper functioning of the enzyme or interferes with the copying process. For instance, if there are contaminating templates present (other, random or undesired stretches of DNA) there may be less binding of primer to proper template, and therefore less product made. Another common problem is with the Magnesium ion concentration in the mixture - MgCl2 is the necessary salt in the reaction mixture, and it has to be at a certain level of concentration for the reaction to work well. If a metal-ion-binding substance is present, such as EDTA, the actual concentration of Mg++ in the solution will be less than calculated, and the reaction will work less well or not at all. Other common substances that can inhibit the reaction include alcohols and phenol (carbolic acid); both commonly used in DNA isolation and purification. It's important to make sure that the DNA you're using for PCR is as pure as possible and is dissolved in a water or Tris buffer, with minimal or no amounts of these chemicals, or your reaction will be inhibited (you won't get much (or any) product).

Answer 2

Highly technical.
Inhibition means the imposition of restraint, or arrest of a progress.
Inhibitor means a substance or agent that depresses the activity of another substance or agent, particularly a substance which checks the action of an enzyme or a tissue organizer, or the growth of microorganisms.

Thermostable Chimeric DNA Polymerases with High Resistance to Inhibitors
(By Andrey R. Pavlov, Nadejda V. Pavlova, Sergei A. Kozyavkin and Alexei I. Slesarev)
"We have developed and put to use a new technology for production of chimeric DNA polymerases with outstanding thermostability, processivity and resistance to PCR inhibitors. The protein chimeras contain polymerase domains fused with helix-hairpin-helix (HhH) domains derived from topoisomerase V of M. kandleri. The advantages of new polymerases allow for cycle sequencing and PCR in high salt concentrations and at temperatures inaccessible for other DNA polymerases. Our approach resulted in TOPOTAQ series of DNA polymerases, which represent an excellent choice for DNA amplification in samples with intercalating dyes (SYBR green, SYBR gold, ethidium bromide, indigo), organic solvents (phenol), and physiological fluids (such as blood and urine)".
Please note that I am not a medical professional.
Please see the web pages for more details on PCR.