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)

A newly established human leukemia cell line, OM9;22, is reported, with B-precursor immunophenotype (CD10+ CD19+ CD22+ HLA- DR+ C mu-) and CD13 antigen, originated from a 19-year-old female patient with Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL). The OM9;22 cells carry a Philadelphia (Ph) translocation and hybrid message detected by a minor-breakpoint cluster region (BCR) exon 1/ABL exon 2 junctional probe using reverse transcriptase polymerase chain reaction. The genetic alterations are consistent with those observed in the donor's leukemia cells, allowing us to conclude that this cell line is a minor-BCR rearranged Ph-positive ALL (Ph+ ALL). Colony formation of the OM9;22 cells in methylcellulose culture is enhanced by the addition of human interleukin 7 (IL-7). In liquid culture, more than 80% of IL-7-treated OM9;22 cells express CD20 antigen but fail to express surface immunoglobulins or cytoplasmic mu-chain, indicating that the cells have a potential of limited maturation by IL-7. By contrast, IL-4 suppresses the colony formation of the OM9;22 cells. These findings suggest that this cell line might be a model of B-precursor human leukemia with proliferative capability by IL-7.
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PMID:Interleukin-7 enhances colony growth and induces CD20 antigen of a Ph+ acute lymphoblastic leukemia cell line, OM9;22. 768 4

Two new myeloid cell lines (K051 and K052) were established from a patient with multilineage CD7-positive acute leukemia. The K051 and K052 were established from the patient's bone marrow cells at diagnosis and at relapse, respectively. The K051 cell expressed myeloid-associated antigens (CD13 and CD33), a platelet-associated antigen (CD41), and an erythroid antigen (glycophorin A). The K052 cell expressed myeloid-associated antigens (CD13, CD14, and CD33), lymphoid markers (CD2, CD5, and CD7), and HLA-DR. Chromosome analysis of both cell lines showed a 17p- chromosome. Both cell lines were investigated for aberrations of the p53 gene and the N-ras gene. A p53 mutation detected in both cell lines consisted of a C-->T substitution in codon 248. An N-ras mutation detected only in the K052 cell consisted of a G-->C substitution in codon 13. Expression of the multidrug resistance gene (MDR1) was also investigated by the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). MDR1-mRNA was more highly expressed by the K052 cell than the K051 cell, being equivalent to that in HEL cells. The functional MDR1-protein against vincristine was also observed, and its function was inhibited by verapamile and Cyclosporin A. The K052 cells were capable of phenotypic or morphologic differentiation after being incubated with granulocyte colony-stimulating factor, interleukin-2, phorbol 12-myristate 13-acetate, or 1,25-dihydroxy-vitamin D3. In contrast, the K051 cells responded phenotypically to retinoic acid. Thus, the K051 and K052 cell lines will be useful for investigating the cellular and molecular events in leukemogenesis and differentiation, and the mechanism of expression of the MDR1 gene.
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PMID:p53 and N-ras mutations in two new leukemia cell lines established from a patient with multilineage CD7-positive acute leukemia. 769 50

Although ample evidence has been accumulated on the structure and functional role of endothelial cells in blood-brain barrier mechanisms, little is known about the contribution that cerebral pericytes provide to this phenomenon. We have reported recently on a monoclonal antibody specific for cerebral pericytes at blood-brain barrier sites. To confirm the pericytic localization of this antigen, and in order to elucidate its biochemical identity, we have performed immunocytochemical, biochemical, and molecular biological studies. By immunocytochemistry on the light microscopic as well as electron microscopic level, we provide definite evidence that the 140-kDa antigen recognized by this monoclonal antibody is confined to cerebral pericytes, whereas endothelial cells are devoid of this antigen. N-Terminal sequencing of the corresponding immunocrossreacting renal protein revealed that the protein detected by the monoclonal antibody is identical to aminopeptidase N. By means of the reverse transcriptase-polymerase chain reaction, the identity of the 140-kDa antigen as aminopeptidase N could also be verified for cerebral microvascular cells. Cerebral pericytic aminopeptidase N may be involved in neurotransmitter (enkephalin) metabolism at the blood-brain interface. By taking into account that brain pericytes have been found to express further plasma membrane-bound enzymes, these results strongly suggest the contribution of cerebral pericytes in the metabolic concert of the homeostatic balance regulated by the blood-brain barrier.
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PMID:The 140-kDa protein of blood-brain barrier-associated pericytes is identical to aminopeptidase N. 791 Jun 34

The present study sought to determine the expression of alpha- and beta-tryptase in in vitro differentiated human cord blood derived mast cells. We also analysed the glycosaminoglycan composition and the phenotype of the cells. The major protease in human mast cells is tryptase, and cDNAs for two different human tryptases have been characterized, the so-called alpha- and beta-tryptase. By reverse transcriptase-polymerase chain reaction (RT-PCR) we could show that stem cell factor (SCF)-dependent cord blood derived mast cells express both alpha- and beta-tryptase. Furthermore, the cells were stained with a monoclonal antibody (mAb) against tryptase, and the tryptase was enzymatically active cleaving the substrate Z-Gly-Pro-Arg- methoxy-2- naphthylamide (MNA). The majority of the cord blood derived mast cells could also be stained with mAbs against chymase, cathepsin G and CD68. They also expressed Kit/SCFR (CD117), CD13, CD29 and CD45 on the cell surface. The proteoglycan-derived polysaccharide composition of the cells was estimated to be 25-35% of heparin origin and 65-75% of chondroitin sulphate origin. Hence, the cord blood derived mast cells exhibit a phenotype in common with the so-called MCTC type of human mast cells.
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PMID:Stem cell factor-dependent human cord blood derived mast cells express alpha- and beta-tryptase, heparin and chondroitin sulphate. 869 Apr 66

Expression of antigens coexpressed on cord blood (CB) CD34+ cells was evaluated by flow cytometry analysis and reverse transcriptase polymerase chain reaction (RT-PCR). Antigen expression was also comparatively analyzed by flow cytometry and limiting dilution (LD) RT-PCR to investigate effects of chymopapain on epitopes of several cell surface markers: LD RT-PCR allows detection of the expression of antigens degraded by chymopapain which are not identified by flow cytometry. Monoclonal antibodies (MoAbs) that recognize chymopapain resistant epitopes on several coexpressed cell surface markers were identified: these included MoAbs directed against CD11a, CD13, CD18, CD38, CD45RO, CD51, HLA-DR, Thy-1, c-kit, flt-3 (STK-1), and mdr-1. Interestingly, chymopapain treatment caused enhanced staining with MoAbs against HLA-DR, Thy-1, flt-3, mdr-1, and CD51. The frequency (LD RT-PCR) of CD18, CD38, Thy-1, and c-kit RT-PCR signals on pure sorted CD34+ CD18-, CD34+ CD38-, CD34+ Thy-1-, and CD34+ c-kit- cells, respectively, was similar in corresponding subsets treated or not with chymopapain. In contrast, the frequency of CD33 RT-PCR signals on sorted CD34+ CD33- cells was higher in chymopapain-treated samples than in untreated samples and thus confirmed at the transcriptional level that the epitope recognized by anti-CD33 is chymopapain sensitive. Our findings extend data on the phenotypic profile of CB CD34+ cells and show that several key cell surface markers of hematopoietic progenitor cells are chymopapain resistant. In addition, the results of the present study demonstrate that the RT-PCR can be applied to the analysis of multiple RNA species in small numbers of hematopoietic progenitor cells and show that LD RT-PCR allows the identification and frequency determination of rare cells which are undetectable by flow cytometry.
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PMID:Surface antigen expression on CD34+ cord blood cells: comparative analysis by flow cytometry and limiting dilution (LD) RT-PCR of chymopapain-treated or untreated cells. 887 54

Serial peripheral blood specimen from eight adult patients after sex-mismatched bone marrow transplantation (BMT) for Chronic Myeloid Leukemia (CML) (N = 3). Ewing sarcoma (N = 1), Acute Myeloid Leukemia (AML) in second remission (N = 1), Acute Lymphoid Leukemia (ALL) (N = 1), of multiple myeloma (N = 2) were analyzed by the simultaneous immunophenotypic (moAbs/ APAAP-staining) and genotypic analysis (for X and Y chromosomes) of interphase cells to characterize mixed chimerism, residual host cells, and leukemic relapse. Although a stable donor chimerism for T cells, myelomonocytic cells, and granulocytes was developed in seven of the eight patients at Days +21 to +28 post BMT, 0.5 to 1% host cells of different lineages remained continuously in five of the eight patients post BMT (> day 100). In two patients, one with common ALL and the other with multiple myeloma and long-term stable mixed chimerism, a tumor cell relapse was detected first in a sample at Day +176 and confirmed at Day +294. These malignant cells were genotypically of host origin and presented phenotypes identical to those at diagnosis. In the three patients with CML, residual host cells were identified as CD13 (Patient 3) of CD13/CD34 (Patient 4) positive and in one case as CD4/CD8 positive (Patient 7). Since no exclusive antigenic marker is available for this discrimination in these CML patients, normal host hematopoiesis can interfere with the identification of residual disease. Therefore, the identification of the bcr-abl transcripts by a two-step reverse transcriptase-polymerase chain reaction (RT-PCR) was included in this analysis. Patient 3 was bcr-abl positive at [Days +21, +28, +35, and +311, but negative at Days +121 and +400; Patient 4 was bcr-abl positive at only Day +166 post BMT. These results are interpreted as signaling a continuing risk of relapse. In Patient 7, the bcr-abl RT-PCR was negative at Days +142, +166, and +237. Thus, the combination of the simultaneous immunophenotypic and genotypic analysis and the bcr-abl detection by RT-PCR clearly improves the discrimination between malignant cells and normal residual host cells.
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PMID:Qualitative assessment of mixed chimerism after allogeneic bone marrow transplantation with regard to leukemic relapse. 893 46

Although acute myeloid leukemias (AMLs) cytochemically negative for myeloperoxidase are now well recognized, myeloid surface antigen-negative AMLs are rare. The morphologic, cytochemical, immunologic, and cytogenetic or molecular features of such cases are described in four adults aged 19 to 60 years. All had AML with maturation (FAB M2) and were myeloperoxidase positive. Immunologic studies showed all to be HLA-DR positive but negative for the CD13, CD14, and CD33 antigens. Two of four were CD34 antigen positive. Cytogenetic studies were performed in three patients, and all demonstrated t(8;21)(q22;q22). In studies using the reverse transcriptase polymerase chain reaction in two patients, including the patient in whom karytypic analysis was not performed, the AML1-ETO fusion product of t(8;21) was identified. These findings suggest an association between the lack of myeloid antigen expression in myeloperoxidase-positive AML and the presence of t(8;21). In addition, the results demonstrate the continued need for cytochemical studies in the evaluation of acute leukemias.
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PMID:Presence of t(8;21)(q22;q22) in myeloperoxidase-positive, myeloid surface antigen-negative acute myeloid leukemia. 1176 84

The t(16;21)(p11;q22) translocation is a non-random chromosomal aberration observed in several types of human acute myeloblastic leukemia (AML), whereas the der(16)t(1;16) and chromosome rearrangements at 12q13 are frequently found in solid tumors. A novel cell line YNH-1 was established from peripheral blood cells of a 46-year-old male with AML (M1) carrying t(16;21) and t(1;16) translocations. YNH-1 has been maintained with a doubling time of 82 h for more than 20 months as a granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) dependent line. Morphologically YNH-1 cells were free-floating immature myeloblasts with lobulated nuclei and vacuoles in the cytoplasm. They were positive for myeloperoxidase but negative for alpha-naphthyl butylate esterase and chloroacetate esterase stainings. In surface marker analysis YNH-1 cells were positive for CD13, CD33 and CD34. Chromosomal analysis showed 46, XY, der(16)t(16;21)(p11;q22)t(1;16) (q12;q13), der(21)t(16;21)(p11;q22), der (6)t(6;12)(q13;q13), der(12)t(6;12)(q21;q13). These translocations were confirmed by fluorescence in situ hybridization (FISH) studies with the ERG-YAC clone and chromosome-specific DNA libraries. Both the FUS/ERG and ERG/FUS chimeric transcripts were identified by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Thus, YNH-1 could be a useful tool for elucidating the pathophysiology and molecular mechanism in AML with t(16;21),t(1;16) and 12q13 translocations.
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PMID:Establishment of a novel human acute myeloblastic leukemia cell line (YNH-1) with t(16;21), t(1;16) and 12q13 translocations. 909 2

A 68 year-old-man was first found to have CLL with IgG, kappa monoclonal gammopathy 6 years ago. Bestrabucil (total dose 35,150 mg) was taken orally from August 1989 to December 1989. Etoposide (total dose 23,100 mg) was then orally administered from January 1990 to December 1995. He was then referred to our hospital in January 1996 because of progressive anemia and thrombocytopenia. Peripheral blood showed a WBC of 21,200/microliter with 4% myeloblasts and 79% lymphocytes, Hb 7.9 g/dl and Plt 5 x 10(4)/microliter. The serum level of lysozyme was increased (75.6 micrograms/ml). Bone marrow aspiration disclosed hyper-cellularity with proliferation of the blasts and a monocytoid cell population, which cytochemical studies demonstrated to be of the myelo-monocytic series, thus indicating acute myelogenous leukemia (AML-M4) superimposed on CLL. Surface marker analysis of bone marrow mononuclear cells revealed reactivity for CD 11c, CD13, CD15, CD33, HLA-DR. The karyotype was normal. Southern blot analysis and reverse transcriptase-polymerase chain reaction did not reveal rearrangement of the MLL gene. Complete remission was achieved by chemotherapy consisted of BHAC, idarubicine, 6MP, vincristine and predonisolone. Long-term treatment with oral etoposide may contribute to secondary AML.
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PMID:[Acute myelogenous leukemia (M4) occurring during chronic lymphocytic leukemia]. 942 40

Superoxide radical (O2-) is ubiquitously critical to the bioactivity of endothelial nitric oxide. In angiotensin-dependent hypertension, vascular O2- levels rise and impede endothelium/nitric oxide-dependent vascular relaxation. We have reported that the major O2- source in the rabbit aorta is adventitial fibroblast phagocyte-like NADPH oxidase and shown that angiotensin (Ang) II treatment of adventitial fibroblasts causes a concentration-dependent increase in particulate NADPH-dependent O2-. From cultured rabbit aortic adventitial fibroblasts treated or not treated with Ang II, we prepared particulate fractions and measured lucigenin-enhanced chemiluminescence. Because [Sar1,Thr8]-Ang II, a generalized antagonist of Ang II and plausible inhibitor of the conversion of Ang II, reversed Ang II (10 nmol/L)-induced NADH- and NADPH-dependent O2- to basal levels, we tested the effect of the inhibitor of aminopeptidase N, amastatin (10 micromol/L), and found no effect on Ang II-stimulated O2-. Ang(1-7), Ang III, and Ang IV also were not effective in stimulating O2- levels at concentrations similar to those of Ang II. Kinetic analysis showed a rise in NADPH oxidase O2- production in response to Ang II, which peaks at 3 hours and returns to basal levels by 16 hours. p67phox, a cytosolic factor, appears to be affected at both the level of transcription and protein synthesis because actinomycin and cycloheximide individually inhibited the observed effect. A partial sequence of p67phox was recovered by reverse transcriptase from mRNA harvested from cultured rabbit aortic adventitial fibroblasts. Furthermore, the p67phox mRNA transcript in aortic fibroblasts is induced by Ang II before the peak of NADPH oxidase by Northern analysis and ribonuclease protection assays. These data suggest that Ang II stimulates NAD(P)H oxidase O2- generation in fibroblasts of aortic adventitia via transcriptional activation of p67phox. These data also provide preliminary evidence for the regulation of factors of the NADPH oxidase and potentially provide a novel means by which to abrogate the development of O2(-)-dependent hypertension.
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PMID:Angiotensin II induces p67phox mRNA expression and NADPH oxidase superoxide generation in rabbit aortic adventitial fibroblasts. 971 63


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