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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Merocyanine 540 (MC540)-mediated photodynamic action is a novel approach for purging tumor cells from autologous remission bone marrow explants. The purpose of this study was to evaluate the effects of hemin (ferriprotoporphyrin IX), a potential source of pro-oxidant iron in bone marrow, on in vitro photodynamic inactivation of leukemia cells. Murine L1210 cells exhibited a progressive loss of clonogenicity when irradiated with broad-band visible light in the presence of MC540. Hemin had strikingly different effects on photokilling, depending on its contact time with cells, eliciting a sizable decrease in resistance after short-term (30-min) contact but a marked increase in resistance after long-term (24-h) contact. Similar trends were observed when cells were challenged with glucose/glucose oxidase, indicating that the responses apply to more than one type of oxidative stress. Immunoblot analyses revealed that the levels of inducible heme oxygenase (HO-1) and ferritin heavy (H) chain were substantially elevated 24 h after hemin addition. HO-1 increased relatively rapidly and maximized within 4 h after adding hemin, whereas H-ferritin increased more slowly in parallel with the development of hyperresistance, maximizing after 24-36 h. Desferrioxamine, an avid iron chelator, had no effect on HO-1 induction but inhibited both ferritin induction and the increase in cell resistance, suggesting that HO-mediated release of iron from hemin was necessary for triggering these responses. Spleen apoferritin was taken up by L1210 cells and strongly inhibited photokilling, further implicating ferritin involvement in hyperresistance. Photokilling was accompanied by free radical-mediated lipid peroxidation (thiobarbituric acid reactivity), which could be suppressed substantially by 24-h hemin preincubation. A plausible explanation for the long-term effects of hemin is that excess H-ferritin generated as a result of iron-regulatory protein deactivation sequesters toxic iron, which might otherwise catalyze damaging lipid peroxidation. Chronic oxidative release of hemin from bone marrow erythroid cells could compromise the efficacy of photopurging by making tumor cells more tolerant to photooxidative insult.
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PMID:Hyperresistance of leukemia cells to photodynamic inactivation after long-term exposure to hemin. 884 Sep 77

Chronic lymphocytic leukemia is a common disease in the elderly but is rarely associated with a nephrotic syndrome. The rarity of this association suggests that leukemic cells may have certain properties or features that may lead to the development of glomerulonephritis. Effective medical treatment of the leukemia may not necessarily allow regression of the nephrotic syndrome; however, the effects of splenectomy on nephrotic proteinuria when associated to chronic lymphocytic leukemia have never been evaluated. We report the case of a 50-year-old male with stage C CD5+ chronic lymphocytic leukemia associated with a nephrotic syndrome due to Type I membranoproliferative glomerulonephritis. Chlorambucil and prednisone were unable to control the leukemia and the nephrotic range proteinuria, and were discontinued because of poor hematologic tolerance. A splenectomy immediately resulted in a spectacular remission of both chronic lymphocytic leukemia and the nephrotic syndrome. Spleen lymphocytes were collected and tested in quantitative flow cytometry for the expression of the main B cell associated markers. They did not exhibit any particular immunophenotypic pattern. This report of a remission of a glomerulonephritis associated with chronic leukemia following splenectomy is evidence of a possible relationship between the two diseases.
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PMID:Nephrotic syndrome associated with chronic lymphocytic leukemia resistant to immunosuppressive drugs: remission obtained by splenectomy. 904 65

Infection of C57BL/6 mice with LP-BM5 murine leukemia virus (MuLV) leads to the development of murine acquired immunodeficiency syndrome (MAIDS) characterized by abnormal lymphoproliferation, hypergammaglobulinemia and severe immunodeficiency. Progression of MAIDS is delayed in X chromosome-linked immunodeficient (XID) mice, which have an abnormality of Bruton's tyrosine kinase (Btk) and lack functionally mature B cells including CD5+ B cells. In this study, we report the following four major findings. (i) Susceptibility to disease induction is not reconstituted by transfer of CD5+ B cells to XID mice. (ii) Spleen cells from asymptomatic XID mice are able to transmit MAIDS to wild-type mice. (iii) MAIDS can be transmitted to XID mice with the transfer of B cells, but not T cells, from C57BL/6 mice with MAIDS. (iv) Cells which undergo massive lymphoproliferation in XID mice with MAIDS by cell transfer are of host origin, but are not from the donor. We suggest from these results that a B cell subpopulation that is impaired in XID mice plays an important role in the initiation of MAIDS.
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PMID:The xid mutation plays an important role in delayed development of murine acquired immunodeficiency syndrome. 904 55

Malignant lymphomas often have complex, nonrandom chromosomal abnormalities. Hepatosplenic gammadelta T cell lymphoma (gammadelta TCL) is an unusual post-thymic T cell lymphoma that primarily involves liver and spleen, often in young adult males. Few cases have had cytogenetic analysis. We report a consistent isochromosome 7q [i(7q)] abnormality in three cases of hepatosplenic gammadelta TCL, one with i(7q) as the sole abnormality at presentation. Three patients, 15-, 37- and 65-year-old males, presented with hepatosplenomegaly and fevers. Histopathologic, immunophenotypic, and molecular genetic studies supported the diagnosis. Spleen, liver, and bone marrow contained sinusoidal infiltrates of atypical lymphoid cells of T cell immunophenotype. PCR performed on two cases demonstrated clonal T cell receptor gamma gene rearrangements. Cytogenetic analysis of bone marrow showed i(7q) as the sole abnormality at presentation in one case. The second case showed i(7q) in addition to two normal chromosomes 7, and other structural and numerical abnormalities. The third case showed i(7q) and a deletion in the long arm of chromosome 11. These findings support the proposal that i(7q) represents the primary nonrandom cytogenetic abnormality in hepatosplenic gammadelta TCL, and plays a role in its pathogenesis.
Leukemia 1997 Aug
PMID:Isochromosome 7q: the primary cytogenetic abnormality in hepatosplenic gammadelta T cell lymphoma. 926 94

Deoxyribonucleoside triphosphate (dNTP) pool imbalances are associated with an increase in the rate of misincorporation and hypermutation during in vitro reverse transcription reactions. However, the effects of in vivo dNTP pool imbalances on the accuracy of reverse transcription are unknown. We sought to determine the effects of in vivo dNTP pool imbalances on retroviral mutation rates and to test our hypothesis that 3'-azido-3'-deoxythymidine (AZT) increases the retroviral mutation rates through induction of dNTP pool imbalances. D17 cells were treated with thymidine, hydroxyurea (HU), or AZT, and the effects on in vivo dNTP pools were measured. Thymidine and HU treatments induced significant dNTP pool imbalances. In contrast, AZT treatment had very little effect on the dNTP pools. The effects of in vivo dNTP pool imbalances induced by thymidine and HU treatments on the retroviral mutation rates were also determined. Spleen necrosis virus (SNV)-based and murine leukemia virus (MLV)-based retroviral vectors that expressed the lacZ mutant reporter gene were used. The frequencies of inactivating mutations introduced in the lacZ gene in a single replication cycle provided a measure of the retroviral mutation rates. Treatment of D17 target cells with 500 microM thymidine increased the SNV and MLV mutant frequencies 4.7- and 4-fold, respectively. Treatment of D17 target cells with 2 mM HU increased the SNV and MLV mutant frequencies 2.1- and 2.7-fold, respectively. These results demonstrate that dNTP pool imbalances are associated with an increase in the in vivo retroviral mutation rates, but AZT treatment results in an increase in the retroviral mutation rates by a mechanism not involving alterations in dNTP pools.
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PMID:Deoxyribonucleoside triphosphate pool imbalances in vivo are associated with an increased retroviral mutation rate. 973 32

A model of mouse acute myeloid leukemia (mAML) was used to study the effector mechanism mediating the graft-versus-leukemia (GVL) effects in recipients of allogeneic bone marrow cells (BMC). mAML-bearing SJL/J (H-2s) mice were lethally irradiated and then transplanted with a mixture of BMC and spleen cells (SC) derived from normal syngeneic or allogeneic mice. To augment the GVL effect, recipients were injected intraperitoneally with recombinant human interleukin-2 (rIL-2) (1.2 x 10(5) IU) for 3 consecutive days, starting one day post BMC + SC transplantation. Spleen cells from treated recipients were adoptively transferred to untreated secondary SJL/J mice to test for the existence of residual tumor cells. All the secondary recipients of SC from mAML-bearing SJL/J mice rescued with syngeneic (SJL/J) or allogeneic (B10.S) BMC+SC (H-2s) differing at minor antigens of the histocompatibility complex (MiHC) developed leukemia and died. In sharp contrast, none of the secondary recipients of SC obtained from identical mAML-bearing mice rescued with B10.S BMC + SC but activated in vivo with IL-2 developed leukemia. Adoptive recipients of SC obtained from mAML-bearing recipients of major histocompatibility complex (MHC)-disparate (C57BL/6, H-2b) cells remained free of leukemia regardless of the use of rIL-2. In parallel with the in vivo findings, a 4-day in vitro exposure of splenocytes to 6 x 10(3) IU/ml rIL-2 resulted in a 5- to 20-fold increase in the frequency of alloreactive cytotoxic T-lymphocyte (CTL) precursors (CTLp) across MiHC and MHC barriers and a 2- to 6-fold increase in their cytotoxic activity. Our data suggest that augmentation of GVL effects by rIL-2 may be due to CTL activation by rIL-2, not excluding the potential beneficial role of rIL-2-activated allogeneic natural killer cells and MHC non-restricted killer cells. Cumulatively, our results suggest potentially beneficial effects of rIL-2, when used jointly with bone marrow transplantation or allogeneic cell therapy, on eradication of leukemia.
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PMID:Correlation between enhancement of graft-versus-leukemia effects following allogeneic bone marrow transplantation by rIL-2 and increased frequency of cytotoxic T-lymphocyte precursors in murine myeloid leukemia. 1114 Aug 83

Studies of retroviral-induced oncogenesis in animal systems led to the initial discovery of viral oncogenes and their cellular homologs, and provided critical insights into their role in the neoplastic process. V-ets, the founding member of the ETS oncogene family, was originally identified as part of the fusion oncogene encoded by the avian acute leukemia virus E26 and subsequent analysis of virus induced leukemias led to the initial isolation of two other members of the ETS gene family. PU.1 was identified as a target of insertional activation in the majority of tumors induced by the murine Spleen Focus Forming virus (SFFV), while fli-1 proved to be the target of Friend murine leukemia virus (F-MuLV) in F-MuLV induced erythroleukemia, as well as that of the 10A1 and Graffi viruses. The common features of the erythroid and myeloid diseases induced by these viruses provided the initial demonstration that these and other members of the ETS family play important roles in hematopoietic development as well as disease. This review provides an overview of the role of ETS genes in retrovirally induced neoplasia, their possible mechanisms of action, and how these viral studies relate to current knowledge of the functions of these genes in hematopoiesis.
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PMID:Ets and retroviruses - transduction and activation of members of the Ets oncogene family in viral oncogenesis. 1117 63

A procedure was developed to generate recombinant single chain Fv (scFv) antibody fragments reacting with the extracellular domain of human cell surface antigen CD13 (hCD13; aminopeptidase N) on intact cells. Membrane fractions prepared from a stably transfected hCD13-positive murine NIH/3T3 cell line were used to immunize BALB/c mice, with the intention that hCD13 would be the major immunogenic molecule recognized by the immune system. Spleen RNA from the immunized mice served to generate a combinatorial scFv phage display library. The library was adsorbed against non-transfected NIH/3T3 or Sf21 insect cells to eliminate nonrelevant binders. The supernatant was then used for panning with either hCD13-transfected Sf21 insect cells or a hCD13-expressing human leukemia-derived cell line. Therefore, the key concepts of the procedure were the presentation of hCD13 as the sole human antigen on murine NIH/3T3 cells and a screening strategy where hCD13 was the major common antigen of the material used for immunization and panning. Two different hCD13-reactive phages were isolated and the soluble scFvs were expressed in E. coli and purified. The two scFvs, anti-hCD13-1 and anti-hCD13-3, differed at four amino acid positions in their V(H) regions and both had high affinities for hCD13 as determined by surface plasmon resonance (K(D)=7 and 33x10(-10) M, respectively). Both efficiently recognized hCD13 on intact cells. Therefore, the procedure allowed the production of high affinity scFvs reacting with a desired antigen in its native conformation without requiring extensive purification of the antigen and should be useful for the preparation of scFvs against other conformation-sensitive cell-surface antigens.
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PMID:An improved procedure for the generation of recombinant single-chain Fv antibody fragments reacting with human CD13 on intact cells. 1129 91

We report an autopsy case of congenital monoblastic leukemia that developed in monozygotic twins. The twin presented with progressive hepatosplenomegaly at 4 weeks after birth. One twin died of massive bleeding and hypovolemic shock before the treatment started. At autopsy, the liver was diffusely enlarged and showed a diffuse whitish discoloration except for the subcapsular and perivenular areas. Microscopic examination disclosed infiltration of histiocyte-like atypical cells along the sinusoids and portal areas of the liver. Spleen, lymph nodes and choroid plexus were also infiltrated by the tumor cells. However, bone marrow involvement of the tumor was minimal although multifocal. On immunohistochemical staining, these atypical cells were reactive for CD68 (PGM-1) and lysozyme, suggesting that the tumor cells might have been derived from mono- histiocyte. Cytogenetic study revealed 9;11 translocation, which is frequently associated with acute monoblastic leukemia. To the best of our knowledge, this is the first report of congenital monoblastic leukemia of monozygotic twins in Korea.
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PMID:Congenital monoblastic leukemia with 9;11 translocation in monozygotic twins : a case report. 1141 Jul 3

Spleen necrosis virus (SNV) proteins can package RNA from distantly related murine leukemia virus (MLV), whereas MLV proteins cannot package SNV RNA efficiently. We used this nonreciprocal recognition to investigate regions of packaging signals that influence viral RNA encapsidation specificity. Although the MLV and SNV packaging signals (Psi and E, respectively) do not contain significant sequence homology, they both contain a pair of hairpins. This hairpin pair was previously proposed to be the core element in MLV Psi. In the present study, MLV-based vectors were generated to contain chimeric SNV/MLV packaging signals in which the hairpins were replaced with the heterologous counterpart. The interactions between these chimeras and MLV or SNV proteins were examined by virus replication and RNA analyses. SNV proteins recognized all of the chimeras, indicating that these chimeras were functional. We found that replacing the hairpin pair did not drastically alter the ability of MLV proteins to package these chimeras. These results indicate that, despite the important role of the hairpin pair in RNA packaging, it is not the major motif responsible for the ability of MLV proteins to discriminate between the MLV and SNV packaging signals. To determine the role of sequences flanking the hairpins in RNA packaging specificity, vectors with swapped flanking regions were generated and evaluated. SNV proteins packaged all of these chimeras efficiently. In contrast, MLV proteins strongly favored chimeras with the MLV 5'-flanking regions. These data indicated that MLV Gag recognizes multiple elements in the viral packaging signal, including the hairpin structure and flanking regions.
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PMID:cis-Acting elements important for retroviral RNA packaging specificity. 1196 12


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