Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thirty three patients with chronic myelogenous leukemia (CML) treated by allogeneic bone marrow transplantation (BMT) were evaluated for bcr/abl mRNA using the reverse transcriptase-polymerase chain reaction (RT-PCR). The bcr/abl mRNA was detected in 22 out of 33 patients in clinical complete remission after BMT. The bcr/abl mRNA was present only transiently in 6 patients. It was speculated that leukemia cells were not eradicated by conditioning therapy of BMT, but patients maintained clinical complete remission due to GVL (graft versus leukemia) effect. Further study is necessary to estimate the clinical value of this technique to predict the outcome in CML patients.
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PMID:[Molecular analysis of bcr/abl mRNA in chronic myelogenous leukemia after bone marrow transplantation by using RT-PCR method]. 160 6

CD34+DR- and CD34+DR+ cells were isolated from the marrow mononuclear cells of five patients with chronic myelogenous leukemia (CML) carrying the Philadelphia (Ph) chromosome. Analysis of bcr/abl hybrid mRNA in individual colonies from a single cell using reverse transcriptase polymerase chain reaction (RT-PCR) demonstrated the presence or absence of the hybrid mRNA. For patient 1 in the chronic phase of CML, the hybrid mRNA was detected in all colonies derived from CD34+DR+ and CD34+DR- hemopoietic progenitors. In contrast, for patient 2 in the chronic phase of CML, the mRNA was detected in all individual colonies from CD34+DR+ progenitors but not in any from CD34+DR- progenitors. For patient 3 in the chronic phase of CML, the mRNA was detected in all individual colonies from CD34+DR+ but in only some of the colonies from CD34+DR- progenitors. For patients 4 and 5 in the acute crisis of CML, the mRNA was found in a portion of colonies from CD34+DR+ and CD34+DR- progenitors. These results indicated that normal clones can persist in CD34+DR- progenitors in some patients with CML, even when chromosome analysis detects the Ph chromosome in all metaphases of bone marrow cells.
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PMID:Absence of bcr/abl gene in single hemopoietic progenitors in some patients with chronic myelogenous leukemia. 750 22

DNA is a very stable molecule and fixation as well as routine histological processing does not destroy its molecular structure. Hence the possibility exists to use this material for molecular genetic analyses. The polymerase chain reaction (PCR) opens the chance to amplify DNA to huge amounts from pathological paraffin and plastic blocks and to use this DNA for further examinations, such as detection of mutations or translocations in malignant tumors, e.g. t(14;18) in follicular lymphomas, bcr/abl in chronic myeloic leukemia, t(11;22) in Ewing sarcomas or of the ras-gene in colon cancer, overexpression of tumor related mRNA, e.g. mdr1-mRNA of the multidrug associated P-Glycoprotein, or detection of foreign DNA from viruses or bacteriae, as well as analysis of hereditary diseases. PCR in its various forms (conventional PCR, PCR with direct sequencing, reverse transcriptase (RT)-PCR, nested primer PCR, quantitative RT-PCR, inverse PCR, degenerated primer (DOP) PCR, in situ PCR, in situ RT-PCR etc.) has proven to supplement routine diagnostic work in many occasions, however, it has to be emphasized that up to now there exists no example for a complete replacement of histological or immunhistological examination by PCR. As consequence, histology remains the first and most important step towards a relevant diagnosis supplemented e.g. by PCR and other techniques of molecular biology.
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PMID:[Polymerase chain reaction in diagnostic pathology]. 753 75

A modified system with two pairs of primers is suggested for the analysis of different bcr/abl mRNA variants, using the polymerase chain reaction (PCR) method. It was demonstrated that, with the use of this method, mRNA preparations obtained from bone marrow cells are more informative than those obtained from blood cells. Fresh preparations of thermostable Tth DNA polymerase, which exhibited the reverse transcriptase activity, appeared to be optimal for PCR analysis of the bcr/abl mRNA pattern.
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PMID:[Use of polymerase chain reaction for determining bcr/abl mRNA in human chronic myeloleukemia]. 753 46

In this paper we describe a patient with bcr/abl positive acute undifferentiated leukemia (AUL) derived from acquired sideroblastic anemia secondary to ifosphamide treatment given for the preceding non-Hodgkin lymphoma of the lung. Cytogenetically, Philadelphia chromosome was not detected through the whole course in this patient, and multiple chromosomal abnormalities including 5q- and monosomy 7 were found at the stage of sideroblastic anemia. The reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed no bcr/abl fusion transcript at the diagnosis of malignant lymphoma. The mRNA encoding the major bcr/abl fusion protein then appeared in the stage of sideroblastic anemia. Finally, the mRNA encoding both major and minor bcr/abl was detected in the stage of AUL transformation. MLL gene rearrangement was not found by RT-PCR analysis at any stage of the disorder. These results may be direct evidence for the induction of the bcr/abl fusion gene by treatment with an alkylating agent (ifosphamide).
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PMID:Detection of major and minor bcr/abl fusion gene transcripts in a patient with acute undifferentiated leukemia secondary to treatment with an alkylating agent. 759 51

The WT 1 gene has been isolated as a tumor suppressor gene of Wilms' tumor. Using reverse transcriptase-polymerase chain reaction (RT-PCR), relative levels of the WT 1 gene expression was examined in 87 patients with acute leukemia, 25 with chronic myelogenous leukemia (CML), and 24 with non-Hodgkin's lymphoma (NHL). Significant levels of the WT 1 gene were expressed in all leukemia patients, and for CML the levels increased as the clinical phase progressed. No point mutations were found in the WT 1 gene when samples from 15 acute leukemia patients were subjected to PCR single-strand conformation polymorphism analysis. In striking contrast to acute leukemia, the levels of WT1 gene expression for NHL were significantly low or even undetectable. The levels of WT 1 gene expression inversely correlated with the prognosis of acute leukemia. The quantification of the WT 1 gene expression made it possible to detect minimal residual disease (MRD) in acute leukemia regardless of the presence of absence of tumor-specific DNA markers. Simultaneous monitoring of MRD by RT-PCR using primers for specific DNA markers in four patients (two AML-M3 with PML/RAR-alpha, one AML-M2 with AML1/ETO, and one CML with bcr/abl) detected MRD comparable to that obtained from quantitation of WT 1 gene expression. In a patient with acute promyelocytic leukemia, the limits of leukemic cell detection by RT-PCR using either WT 1 or PML/RAR-alpha gene primers were 10(-3)-10(-4) and 10(-4) for bone marrow, and 10(-5) and 10(-4) for peripheral blood, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[WT 1 and leukemia]. 764 50

We describe the polymerase chain reaction (PCR) method using stained bone marrow smears as sources of RNA. The amount of extractable RNA decreased during the process of making and staining bone marrow smears. The sensitivity of the reverse transcriptase-based polymerase chain reaction (RT-PCR) method for detecting target mRNA-positive cells in 5 x 10(5) suspended cells and stained bone marrow smears were 1:10(5) and 1:5000, when we used K562 cells. The bone marrow smears of 21 patients with chronic myelogenous leukemia (CML) were examined using this method. We extracted RNA from stained specimens stored at room temperature for 5-14 years. Twelve of 21 (57%) smears showed positive results for bcr/abl. The carrier RNA improved the recovery when added at the step of RNA extraction. These data indicate that mRNA is present in stained bone marrow smears for at least 14 years and that the sensitivity of RT-PCR is adequate for molecular analysis.
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PMID:Detection of bcr/abl mRNA in stained bone marrow smears. 788 52

The in vitro sensitivity of human chronic myeloid leukemia-blast crisis and chronic phase (CML-BC and CML-CP, respectively) cells as well as adherent cell-depleted, T lymphocyte-depleted normal bone marrow cells (A-T-NBMC) to various concentrations of mafosfamide (ASTA Z7654), was examined by colony formation assay in the presence of IL-3 and GM-CSF, to test the possibility of purging of BMC from CML cells. Colony formation by CML cells was inhibited more efficiently than by NBMC. After the incubation with 50 micrograms/ml or 100 micrograms/ml of mafosfamide, the growth of leukemic CFU-GM was totally abrogated in 2/11 or 9/11 cases of CML-BC and in 1/7 or 6/7 cases of CML-CP, respectively. At the same time the CFU-GM arising from normal BMC were not inhibited totally with 50 or 100 micrograms/ml of the drug in any of five experiments. CML cells were still unable to form secondary colonies, while normal BMC were capable of regrowth. The CD34+ cells isolated form CML-BC and CML-CP patients were also more susceptible to mafosfamide cytotoxicity in comparison to CD34+ cells derived from NBMC. To confirm the possibility of purging, CML-BC cells were mixed with NBMC (1:1) and incubated with mafosfamide. Finally, the growing colonies were examined for the presence of bcr/abl hybrid gene by reverse transcriptase-Taq polymerase chain reaction (RT-PCR) and specific hybridization. The bcr/abl gene was not detected in the colonies growing after 100 micrograms/ml, and the signal was diminished after incubation with 50 micrograms/ml of mafosfamide, as compared to control. These results strongly suggest that high concentrations of mafosfamide may be useful for the purging of autologous BMC from CML cells.
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PMID:Successful mafosfamide purging of bone marrow from chronic myelogenous leukemia (CML) cells. 813 96

The bcr/abl fusion gene in 20 patients with chronic myeloid leukemia (CML) was detected by RNA polymerase chain reaction, which used mRNA as the starting material to generate cDNA with reverse transcriptase followed by PCR amplification (RNA/PCR). Amplification of a sequence spanning the bcr/abl junction region was achieved by using peripheral blood cells as the source of mRNA from all 20 patients with CML, including 3 cases of Ph (-) CML, and cell line K562 was derived from patients with CML. No amplification was seen when mononuclear cells from 3 normal individuals, 2 patients with lymphoma and cell line HL-60 were used. The presence or absence of bcr exon 3 in the fusion mRNA was determined by the size of the amplified fragments. Of the 20 CML patients, 15 showed only the 165-bp amplified band (indicating retention of bcr exon 3), one showed only the 90-bp amplified band, and 4 showed both 165-bp and 90-bp bands. Both bands were seen more frequently in blast crisis than in remission and chronic phase.
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PMID:Detection of the BCR/ABL fusion gene in chronic myeloid leukemia by RNA polymerase chain reaction. 829 58

The outcome of 14 bone marrow transplants (BMT) (autologous 4; allogeneic 10) for Philadelphia-chromosome (Ph1) positive acute lymphoblastic leukemia (ALL) was analyzed. Preparative regimens consisted of etoposide (VP16) (30 or 45 mg/kg BW) (n = 14), cyclophosphamide (CY)(120 mg/kg BW) (n = 14), and total body irradiation (TBI)(12 Gy) (n = 13) or busulfan (Bu)(16 mg/kg) (n = 1). All patients receiving autologous marrow were in complete remission (CR) (three patients in 1.CR, one patient in 2.CR) at the time of BMT. For allogeneic BMT (nine related, one unrelated donor), seven patients were in first CR, two patients in first refractory relapse, and one patient in second relapse. With a median follow-up of 503 days (range 93-1522 days), eight out of 14 patients are alive in remission (six out of 10 patients receiving allogeneic, and two out of four patients receiving autologous BMT). Disease-free survival for all patients is 46%. Causes of death were relapse (n = 3) and transplant-related toxicity (n = 3). All patients tested for the bcr/abl rearrangement by reverse transcriptase-polymerase chain reaction (RT-PCR) were negative 4 weeks post-BMT. Two of the three patients who subsequently relapsed were repeatedly RT-PCR positive prior to relapse (test not done in the third). Considering the negligible cure rate of Ph1-positive ALL with conventional chemotherapy regimens, our data support the concept of early (> or = 1 CR) BMT (allogeneic > autologous (purged) following triple therapy with TBI, VP16, and CY.
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PMID:Bone marrow transplantation for Philadelphia-chromosome-positive acute lymphoblastic leukemia. 854 63


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