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Topic: Philadelphia chromosome

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In the News (Sun 16 Jun 19)

  Philadelphia chromosome - Wikipedia, the free encyclopedia
Philadelphia chromosome or Philadelphia translocation is a specific genetic, chromosomal abnormality that is associated with chronic myelogenous leukemia (CML) and involves an exchange of material between chromosomes 9 and 22.
The Ph chromosome is also found in acute lymphoblastic leukemia (ALL, 25–30% in adult and 2–10% in pediatric cases) and occasionally in acute myelogenous leukemia (AML).
The result is that part of the BCR ("breakpoint cluster region") gene from chromosome 22 (region q11) is fused with part of the ABL gene on chromosome 9 (region q34).
en.wikipedia.org /wiki/Philadelphia_chromosome   (590 words)

 Philadelphia chromosome (Ph) definition - Cancer information on MedicineNet.com
Philadelphia chromosome (Ph): The chromosome abnormality that causes chronic myeloid leukemia (CML).
The Ph chromosome is an abnormally short chromosome 22 that is one of the two chromosomes involved in a translocation (an exchange of material) with chromosome 9.
The discovery in Philadelphia in 1960 of the Ph chromosome was a landmark.
www.medterms.com /script/main/art.asp?articlekey=4870   (529 words)

 Chromosome 22 - Genetics Home Reference
Chromosome 22 is one of the 23 pairs of chromosomes in humans.
Chromosome 22 is the second smallest human chromosome, spanning about 49 million base pairs (the building blocks of DNA) and representing between 1.5 percent and 2 percent of the total DNA in cells.
Genes on chromosome 22 are among the estimated 20,000 to 25,000 total genes in the human genome.
www.ghr.nlm.nih.gov /chromosome=22   (874 words)

 Life on Earth, 2/E Chapter 8 -- Issues in Biology   (Site not responding. Last check: 2007-08-19)
Long before it was known that the DNA of chromosomes carries the genetic code, scientists had been studying chromosome structure in a variety of organisms.
Because Nowell and Hungerford worked in Philadelphia, this tiny chromosome 22 came to be called the Philadelphia chromosome by other researchers, who began to investigate the possible link between this chromosome and the development of leukemia.
On the basis of improved chromosome staining techniques, other researchers discovered that, in people with a Philadelphia chromosome, a portion of chromosome 22 had broken off and was joined to chromosome 9.
cwx.prenhall.com /bookbind/pubbooks/audesirk2/chapter8/essay1/deluxe-content.html   (601 words)

 Reciprocal Translocation: Philadelphia Chromosome   (Site not responding. Last check: 2007-08-19)
This person has 46 chromosomes with a translocation of material between chromosome 9 and chromosome 22 (commonly known as the Philadelphia chromosome).
The connection between this chromosomal abnormality and CML was clarified by studying the genes located on the chromosomes at the sites of the translocation breakpoints.
In one of the translocated chromosomes, part of a gene called abl (pronounced A-ble) is moved from its normal location on chromosome 9 to a new location on chromosome 22.
gslc.genetics.utah.edu /units/disorders/karyotype/reciprocal.cfm   (186 words)

 The Philadelphia Story   (Site not responding. Last check: 2007-08-19)
By 1882, Flemming observed threadlike chromosomes in the nuclei of dividing cells.
Chromosomes are identified and arranged by their characteristic size, shape, and centromere location and staining patterns.
A translocation occurs when a part of one chromosome is transferred to a nonhomologous chromosome; example is a form of cancer where a segment of chromosome #22 is on #9 (Philadelphia chromosome).
www.wilson.hlpusd.k12.ca.us /science/Dobrenen/lectch11p.html   (1127 words)

 Stories of Discovery, Infrastructure Needed for Cancer Research: NCI's Challenge - 2003   (Site not responding. Last check: 2007-08-19)
It was the first chromosome abnormality ever found to be associated with a specific cancer and the first indication that tumors might indeed arise from changes beginning in just one cell.
While the link between the Philadelphia chromosome and CML led scientists to suspect a causal relationship, the location of the missing DNA from chromosome 22 and how it might lead to CML was a mystery to be solved over the next three decades.
They found that the break on chromosome 22 occurs in the middle of the bcr gene and that the break on chromosome 9 occurs in the abl gene.
plan2003.cancer.gov /infra/sod.htm   (1567 words)

 MedlinePlus Medical Encyclopedia: Karyotyping
Karyotyping is a test to identify chromosome abnormalities as the cause of malformation or disease.
For this reason it is often prudent to repeat the karyotype test to confirm that the abnormal chromosome constitution is in the body of the patient.
Mixtures of 2 different populations of cells or chromosome constititutions are sometimes observed.
www.nlm.nih.gov /medlineplus/ency/article/003935.htm   (786 words)

 DNA Details Suggest How Human Chromosomes Break, Rearrange and Cause a Genetic Disease   (Site not responding. Last check: 2007-08-19)
When chromosomes 11 and 22 break, then exchange genetic material in a balanced translocation, the genes retain their normal function and a person carrying the abnormal chromosomes has no symptoms of disease.
Unlike more random chromosome translocations, the translocation between chromosomes 11 and 22 occurs time and again in a population, suggesting that the specific locations where the chromosomes break are structurally unstable.
The current study of chromosome structure builds on more than 20 years of research conducted by the Children's Hospital team on chromosome 22, as well as the team's participation in the federally sponsored Human Genome Project, the multicenter effort to compile the order of the 2 billion DNA bases of all 23 human chromosomes.
www.prnewswire.com /cgi-bin/stories.pl?ACCT=104&STORY=/www/story/06-22-2000/0001249959&EDATE=   (874 words)

In the case of the Philadelphia chromosome, an accident known as a translocation occurs.
Van Hoeck ======================================================== The Philadelphia chromosome (named for the city in which it was discovered) is the name for a particular rearrangement of chromosomes called a translocation.
The Philadelphia chromosome is a reorganization of the chromosomes so that the ends of chromosomes 9 and 22 break off and switch places.
www.newton.dep.anl.gov /askasci/zoo00/zoo00072.htm   (625 words)

 Understanding CML
In CML, the translocation occurs between chromosomes 9 and 22 (human DNA is packaged in 23 pairs of chromosomes) and produces a new, abnormal gene called BCR-ABL.
The Philadelphia chromosome is an acquired mutation — that is, a person is not born with it and it is not passed on to their children.
The bone marrow sample is then examined by chromosome and/or molecular techniques for the presence of the Philadelphia chromosome.
www.cmlvaccine.com /understanding.html   (575 words)

 Chronic Myelogenous Leukemia (CML)
The Philadelphia Chromosome (Ph In most cases of CML, the leukemic cells share a chromosome abnormality not found in any nonleukemic white blood cells, nor in any other cells of the patient's body.
This abnormality is a reciprocal translocation between one chromosome 9 and one chromosome 22.
The latter is called the Philadelphia chromosome and designated Ph The DNA removed from chromosome 9 contains most of the proto-oncogene designated c-ABL.
users.rcn.com /jkimball.ma.ultranet/BiologyPages/C/CML.html   (753 words)

 Philadelphia Gene
The Philadelphia chromosome (named because it was discovered at hospital in Philadelphia), is actually what is known as a balanced, or reciprocal, translocation.
The gene from chromosome 9 is called "abl" and the gene from 22 is called "bcr." "Abl" is a gene that plays a role in normal cell division.
Thus, it seems that CML results from a "somatic cell" translocation, "between the paternally derived chromosome 9 and the maternally derived chromosome 22" in a white blood cell precursor within the bone marrow causing its unrestricted proliferation, as opposed to a genetic defect that could be passed on through the "germ line cells".
www.newton.dep.anl.gov /askasci/mole00/mole00336.htm   (903 words)

 Chromosome Losses Mean Poor Survival In Childhood Leukemia
All the children had cancers showing the Philadelphia chromosome, an alteration in the genes that indicates a poorer response to treatment.
Sixty-one percent of the patients (153), showed secondary chromosome abnormalities; that is, abnormalities present in addition to the Philadelphia chromosome.
The Philadelphia chromosome, which occurs in 2 to 5 percent of children with ALL, is an abnormal chromosome that sometimes occurs in several types of childhood and adult leukemias.
researchnews.osu.edu /archive/chromosom.htm   (591 words)

 Center News - 1/4/2001 - Treatment for CML, gastrointestinal-tract tumors
A hallmark of CML patients, the Philadelphia chromosome is formed when a segment of normal chromosome 9 fuses to a broken chromosome 22, as shown above.
The Philadelphia chromosome has a novel fusion gene, BCR-ABL, which is formed where the breakpoints of the two chromosomes have joined.
Even a few remaining Philadelphia chromosome-positive cells pose a risk for future cancer recurrence, leading some researchers to speculate that Gleevec may need to be administered for prolonged periods, perhaps throughout a patient's life.
www.fhcrc.org /about/pubs/center_news/2001/jan4/sart4.html?&&printfriendly=yes   (992 words)

 Mayo Clinic Proceedings
Individual chromosome visualization and distinction are further enhanced by special dye-staining techniques (eg, Giemsa staining, aka, G-banding) that create a series of characteristic bright and dark bands of different length and brightness that distinguish adjacent segments.
In the remaining 5%, the Philadelphia chromosome might be either masked (submicroscopic bcr/abl fusion) or part of a complex/variant chromosomal translocation (involvement of other chromosome breakpoints in addition to 9q34 and 22q11).
The molecular assays used to detect the Philadelphia chromosome translocation do not require the presence of dividing cells and can be performed on both the peripheral blood and the bone marrow specimens with equivalent results.
www.mayoclinicproceedings.com /inside.asp?AID=863&UID=   (9547 words)

 ACP - Wisconsin Chapter - A Novel Treatment for Philadelphia Chromosome Positive Leukemia
Cytogenetic studies are typically associated with an abnormal chromosome 22, also known as the Philadelphia chromosome.
It targets the abnormality produced by the t(9,22) chromosomal translocation present in about 85% of patients with CML and 20 to 30% of adult patients with acute lymphoblastic leukemia (ALL).
Bone marrow aspirate was obtained and cytogenetics were positive for the Philadelphia chromosome.
www.acponline.org /chapters/wi/associates/2001/vignette32.htm   (320 words)

While they are still attached, it is common to call the duplicated chromosomes sister chromatids, but this should not obscure the fact that each is a bona fide chromosome with a full complement of genes.
It is most often studied when the cell is at metaphase of mitosis and all the chromosomes are present as dyads.
The packing reaches its extreme during mitosis when a typical chromosome is condensed into a structure about 5 µm long (a 10,000-fold reduction in length).
users.rcn.com /jkimball.ma.ultranet/BiologyPages/C/Chromosomes.html   (821 words)

 Online Encyclopedia and Dictionary - Philadelphia chromosome   (Site not responding. Last check: 2007-08-19)
In the late 1990s, Dr Brian J. Druker identified the compound then known as STI-571 as having an inhibitory effect on bcr-abl.
The phenomenon was first discovered and described in 1960 by scientists from Philadelphia, Peter Nowell from University of Pennsylvania School of Medicine and David Hungerford from the Institute for Cancer Research and therefore named after the city.
Nowell P, Hungerford D. A minute chromosome in chronic granulocytic leukemia.
www.fact-archive.com /encyclopedia/Philadelphia_chromosome   (481 words)

 Re: What is the Philadelphia Chromosome?
Dear Amy, The Philadelphia Chromosome is a characteristic cytogenetic abnormality associated with leukemia (CML - chronic myeloid leukemia - and some acute cases) as you have found in your literature.
The Philadelphia chromosome results from a reciprocal translocation between chromosomes 9 and 22 [t(9;22)(q34;q11)].
In CML, the Philadelphia chromosome is present in all cells of the myeloid lineage, including neutrophils, erythroblasts, megakaryocytes, monocytes, eosinophils and basophils.
www.madsci.org /posts/archives/2000-11/974576457.Ge.r.html   (116 words)

 News - Chromosomal Abnormalities Can Occur During Imatinib Therapy in Philadelphia chromosome-negative metaphases in ...
Cytogenetic abnormalities are detected in Philadelphia chromosome (Ph)-negative cells in a fraction of patients with chronic myelogenous leukaemia (CML) treated with imatinib mesylate in the chronic phase of the disease, according to a recent American study.
CML is a myeloproliferative disorder characterized by a specific cytogenetic abnormality known as the Philadelphia chromosome (Ph).
Overall, 25 chromosomal abnormalities were detected in the Ph-negative cells of 21 patients, representing only 8% of 272 patients who achieved a cytogenetic response.
www.docguide.com /news/content.nsf/news/8525697700573E1885256DD0003377BA?OpenDocument&c=Leukemias&count=10   (650 words)

 Hematology highlights: Making the Philadelphia chromosome disappear - Drug Topics
The Philadelphia (Ph) chromosome, which occurs in 95% of cases of chronic myeloid leukemia and sometimes other types of leukemias as well, was discovered in 1960 in Philadelphia, the site of the 2002 American Society of Hematology (ASH) meeting.
The ABL-BCR Ph chromosome consists of a translocation between the long arms of chromosomes 22 and 9, in which the ABL proto-oncogene is transported to the BCR, or breakpoint cluster, on 22q.
And, coming full circle here in Philadelphia decades later, reports indicated that the Ph chromosome can indeed be made to disappear, with what looks like the best treatment yet for this disease, both early on and for the longer term.
www.drugtopics.com /drugtopics/article/articleDetail.jsp?id=110826   (1129 words)

 National Cancer Institute - Discoveries Leading to FDA Approval of Gleevec
A new consistent chromosomal abnormality of chronic myelogenous leukemia identified by quinacrine fluorescence and Giemsa staining.
A cellular oncogene is translocated to the Philadelphia chromosome in chronic myelocytic leukemia.
Activity of a specific inhibitor of the BCR-ABL tyrosine kinase in the blast crisis of chronic myeloid leukemia and acute lymphoblastic leukemia with the Philadelphia chromosome.
www.cancer.gov /newscenter/pressreleases/gleevectimeline   (849 words)

 Gleevec® Effective in Acute Lymphoblastic Leukemia   (Site not responding. Last check: 2007-08-19)
Philadelphia chromosome-positive ALL is a subtype of ALL in which a genetic abnormality, referred to as the Philadelphia chromosome, results in constantly activated growth of cancer cells.
Philadelphia chromosome-positive ALL represents 40% of all cases of ALL in patients over the age of 40.
Gleevec® is approved by the FDA for the treatment of adult and pediatric patients with a different type of leukemia, called chronic myeloid leukemia, in which the majority of cases are Philadelphia chromosome-positive.
www.411cancer.com /syndication/veContent.jsp?ArticleID=leukemia_dec03_2&ArticleTypeID=NEWS   (635 words)

 Tracking Treatment Progress: Lab Tests For CML
STEVE MACKINNON, MD: Well, in chronic myeloid leukemia there is a cytogenetic or chromosomal abnormality that's called the Philadelphia chromosome, and that is a translocation between chromosome 9 and chromosome 22, and that is characteristic of this disease.
The next goal would be to reduce the measurable amount of leukemia in their body, measuring the leukemia with cells carrying the Philadelphia chromosome in the blood, and cells carrying the Philadelphia chromosome in the bone marrow.
Monitoring that response is important, for doctors believe the fewer cells with the Philadelphia chromosome, the longer a patient may live.
nydailynews.healthology.com /nydailynews/15963.htm   (1510 words)

 Detection of bcr-abl Transcripts in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia After Marrow ...
THE PHILADELPHIA chromosome (Ph) is the hallmark of chronic myeloid leukemia (CML) and also occurs in approximately 5% of children and 20% of adults with acute lymphoblastic leukemia (ALL).
Molecular analyses have established that the Ph translocation results in the joining of 3' sequences of the tyrosine kinase c-ABL proto-oncogene on chromosome 9 to the 5' sequences of the BCR gene on chromosome 22.
The endpoint of relapse was defined as either the presence of leukemic blasts in the BM or peripheral blood or evidence of the Ph chromosome on cytogenetic examination.
www.bloodjournal.org /cgi/content/full/89/7/2602   (5529 words)

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