Resistance to CML Drugs & P C R tests

[Guest guest]

What Does Resistance Mean?

A small percentage of Ph+ CML patients either fail to respond to treatment or

lose their response over time. When this happens, it is called drug resistance.

Researchers continue to investigate why some patients never respond well to

GLEEVEC. However, they have a good understanding of why some people lose their

response—even after years of successful treatment.

What causes resistance?

Over time the Bcr-Abl protein, the signal that tells your body to produce too

many white blood cells, can change or mutate. When this happens, GLEEVEC can

stop working as well as it used to. When GLEEVEC is unable to keep the Bcr-Abl

protein in check, the signal turns on again and your body starts making too many

damaged white blood cells.

How does your doctor know if you are resistant?

Your doctor determines whether or not you are resistant to GLEEVEC by watching

over time to see if you are meeting your treatment goals. This is done by

monitoring your response to treatment using blood and bone marrow tests. If you

fail to meet your treatment goals, or you stop responding well to treatment, you

may be resistant to GLEEVEC. Resistance is often defined by the measurements

below:

a.. At 3 months, your blood counts may not have returned to normal, meaning

you have not had a complete hematologic response (CHR)

b.. At 6 months, 95% or more of your cells still contain the Ph+ chromosome,

meaning you have not had any cytogenetic response (CyR)

c.. At 12 months, 35% or more of your cells still contain the Ph+ chromosome,

meaning you have not had a major cytogenetic response (MCyR)

d.. You have lost a previous CHR, meaning your blood counts have become

abnormal again

e.. You have lost a previous CyR, meaning tests have detected an increase in

the number of Ph+ cells in your blood and bone marrow.

http://tinyurl.com/6zsdn4g

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Polymerase Chain Reaction (PCR)

PCR is a technique widely used in molecular biology. It derives its name from

one of its key components, a DNA polymerase used to amplify (i.e., replicate) a

piece of DNA by in vitro enzymatic replication. As PCR progresses, the DNA thus

generated is itself used as template for replication. This sets in motion a

chain reaction in which the DNA template is exponentially amplified. With PCR it

is possible to amplify a single or few copies of a piece of DNA across several

orders of magnitude, generating millions or more copies of the DNA piece. PCR

can be performed without restrictions on the form of DNA, and it can be

extensively modified to perform a wide array of genetic manipulations.

For more information, visit:

Wikipedia

Gene Almanac

Real-Time Quantitative PCR

Real-time polymerase chain reaction, also called quantitative real time

polymerase chain reaction (QRT-PCR) or kinetic polymerase chain reaction, is a

laboratory technique based on polymerase chain reaction, which is used to

amplify and simultaneously quantify a targeted DNA molecule. It enables both

detection and quantification (as absolute number of copies or relative amount

when normalized to DNA input or additional normalizing genes) of a specific

sequence in a DNA sample.

The procedure follows the general principle of polymerase chain reaction; its

key feature is that the amplified DNA is quantified as it accumulates in the

reaction in real time after each amplification cycle. Two common methods of

quantification are the use of fluorescent dyes that intercalate with

double-strand DNA, and modified DNA oligonucleotide probes that fluoresce when

hybridized with a complementary DNA.

For more information, visit:

Wikipedia

http://www.genpathdiagnostics.com/molecular_diagnostics

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HOW STEM CELL LINES ARE MADE:

How Embryonic Stem Cell Lines are Made

Use of embryonic stem cells in research has been hotly debated for several

years. This animation presents the basics on how stem cell lines are

established. For more information on how techniques similar to this are used in

research, visit DNA from the Beginning and explore Concept 41: DNA is only the

beginning for understanding the human genome.

http://www.dnalc.org/resources/animations/stemcells.html

Animation can be found on YouTube.\

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CML clone (Dr. Sawyers) This is an interesting WebCam and no matter how

much you know or don't know about CML, listen to this..............

http://tinyurl.com/6ed3t74

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FYI,

Lottie Duthu