Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fitness landscapes, which provide a unique perspective for viewing co-evolving cell populations, were used to study the evolution of CML and MDS. This led to several conclusions: (1) accelerated phase CML and RAEB/RAEBt are not specific disease entities. They represent the time when AML cells are replacing preleukemia cells; (2) monoclonal hemopoiesis and RA/RARS represent a variety of clinical syndromes with a common appearance but with different evolutionary potential; (3) malignant cells alter the fitness landscape enhancing their proliferative advantage. These studies provide the basis for new approaches to treatment.
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PMID:Fitness landscapes and the myeloid leukemias. 1007 Nov 32

Differentiation of essential thrombocythemia (ET) from thrombocythemias occurring in various subtypes of chronic myeloproliferative disorders (MPDs) is controversial, because of the lack of uniform clinical and morphological criteria. A retrospective clinicopathologic study was performed on 375 patients presenting with a MPD and a platelet count exceeding 500 x 10(9/)l. For comparison 35 patients with reactive thrombocytosis (RT) and five patients with a myelodysplastic syndrome (MDS-5q(-) syndrome) were enrolled into this study. In addition to a complete clinicopathological work-up, procedures included histochemical and immunological staining techniques and morphometry of bone marrow biopsies for proper evaluation of megakaryocytes (CD61) and erythroid precursors (Ret40f). Because of the high patient's age on admission, relative survival rates with corresponding disease-specific loss of life expectancy were calculated. Analysis of clinical and morphological characteristics, in particular megakaryopoiesis revealed features which enabled a clear-cut distinction between thrombocythemias in MPDs and thrombocythemic states in MDS. This rationale proved to be most important for the diagnostic discrimination of the 33 patients with initial (prefibrotic) stages of idiopathic myelofibrosis (IMF) from ET (40 patients). A new set of relevant criteria for the diagnosis of IMF with special regard to early stages and its distinction from ET has been proposed. Hemorrhagic episodes were more frequently observed in ET than in thrombocythemias associated with polycythemia vera (PV). Computation of specific loss of life expectancy revealed two extremes: thrombocythemia in CML (81%) and ET (3%), whereas thrombocythemias in PV and IMF did not show a significantly different life loss (19-22%). The revised criteria for ET, PV and IMF are reliable by taking histopathological features from bone marrow biopsies into consideration, particularly for the diagnosis of ET and its differentiation from thrombocythemias as a presenting symptom accompanying the various subtypes of MPDs.
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PMID:Clinicopathological diagnosis and differential criteria of thrombocythemias in various myeloproliferative disorders by histopathology, histochemistry and immunostaining from bone marrow biopsies. 1022 1

The two matrix metalloproteinases (MMPs) Mr 72,000 type IV collagenase (MMP-2, gelatinase A) and Mr 92,000 type IV collagenase (MMP-9, gelatinase B) play key roles in tissue remodeling and tumor invasion by digestion of extracellular matrix barriers. We have investigated the production of these two enzymes as well as the membrane-type MMP (MT1-MMP) and the tissue inhibitors of metalloproteinases (TIMPs) TIMP-1 and TIMP-2 in the bone marrow mononuclear cells (BM-MNCs) of patients with acute myeloid leukemia (AML; n = 24), chronic myeloid leukemia (CML; n = 17), myelodysplastic syndromes (MDS; n = 8), and healthy donors (n = 5). Zymographic analysis of BM-MNC-conditioned medium showed that a Mr 92,000 gelatinolytic activity, identified as MMP-9 by Western blotting, was constitutively released from cells of all patients and healthy individuals examined in this study. In contrast, MMP-2 secretion was found to be absent in all samples from healthy donors but present in 8 of 11 (73%) of the samples from patients with primary AML, 7 of 8 (88%) with secondary AML, and only 1 of 5 (20%) cases with AML in remission, indicating MMP-2 to be produced by the leukemic blasts. MMP-2 release was not detected in CML cell-conditioned medium with the exception of two cases, both patients either being in or preceding blast crisis. In MDS, MMP-2 was found in three of eight (38%) of the patients, two of them undergoing progression of disease within 12 months. Quantitative Northern blot analysis in freshly isolated BM-MNCs showed a relatively low constitutive expression of TIMP-1 in all samples, whereas MMP-9 gene transcription was higher in healthy donors and CML samples, than in AML and MDS. Reverse transcriptase-PCR analysis revealed the presence of TIMP-2 mRNA in the majority of MMP-2-releasing BM-MNCs. MT1-MMP expression was present in most samples of patients with MDS or AML but absent in those with secondary AML and CML. Thus, we have shown that BM-MNCs continuously produce MMP-9 and TIMP-1 and demonstrated that leukemic blast cells additionally secrete MMP-2 representing a potential marker for dissemination in myeloproliferative malignancies.
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PMID:Matrix metalloproteinase production by bone marrow mononuclear cells from normal individuals and patients with acute and chronic myeloid leukemia or myelodysplastic syndromes. 1035 46

Treatment-related (Tr) AML and MDS after chemotherapy, radiotherapy, or the combination of both have been well characterized. However, tr-CML seems to differ from these better-known entities in frequency, clinical course, and prognosis. Tr-CML cannot be distinguished from de novo CML cytogenetically, and, in contrast to tr-AML and tr-MDS, typical chromosomal aberrations related to tr-CML have not been described. Treatment-related CML is a late effect of cytotoxic or immunosuppressive therapy which might be increasingly recognized due to a higher number of patients treated with intensive therapy regimens. We review here the available data on incidence of tr-CML as well as the affected individual's characteristics with regard to different treatment options in malignant and nonmalignant diseases.
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PMID:Treatment-related chronic myelogenous leukemia. 1046 Mar 47

Between October 1995 and October 1998, 24 children aged 9 months to 17 years (median 11 years) underwent cytokine-mobilized allogeneic peripheral blood stem cell (PBSC) transplantation for treatment of hematological disorders. All of the transplants were the first allogeneic transplant for the recipient. Twenty patients were transplanted for hematological malignancies (ALL = 8, AML = 6, CML = 4, MDS = 2) and four patients were transplanted for non-malignant disease (thalassemia major = 2, Wiskott-Aldrich syndrome = 1, Kostmann's syndrome = 1). Nineteen donors were HLA-identical siblings, four were HLA-matched or single antigen mismatched parents, and one was a syngeneic transplant. Donors aged 8 to 38 years (median 15 years, 14 donors <18 years) received G-CSF 10 microg/kg/day subcutaneously beginning 4 days before PBSC collection and were submitted to one to three leukapheresis collections. The median CD34+ cell yield was 7.8 x 106 cells/kg recipient body weight. All patients achieved an ANC >0.5 x 109/l after a median of 13 days (range 10-21). Twenty-three patients eventually achieved platelet transfusion independence. One patient died on day 63 without ever achieving platelet transfusion independence. Four patients received platelet transfusions to maintain a platelet count well above 20 x 109/l due to bleeding complications. Of the 19 evaluable patients, the median time to a non-transfused platelet count of 20 x 109/l was 12 days (range 0-44). Ten of 23 at-risk patients developed acute GVHD grades II to IV, with grades III to IV in four patients. Twelve of 19 patients followed for at least 100 days have developed chronic GVHD (extensive = 2, limited = 10) with an actuarial risk of chronic GVHD of 75% at 1 year. The Kaplan-Meier estimate of event-free survival is 65% at 2 years. Four patients died (GVHD = 3, VOD = 1), three patients relapsed, and one patient with thalassemia major had a late graft failure with autologous recovery. Based upon our experience, allogeneic PBSCT is safe for both pediatric donors and recipients and engraftment of neutrophils and platelets is rapid. Bone Marrow Transplantation (2000) 25, 13-18.
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PMID:Cytokine-mobilized allogeneic peripheral blood stem cell transplants in children result in rapid engraftment and a high incidence of chronic GVHD. 1065 8

We studied telomerase regulation and telomere length in hematopoietic progenitor cells from peripheral blood and bone marrow from patients with acute and chronic leukemia and myeloproliferative diseases. CD34+ cells from a total of 93 patients with either acute myeloid leukemia (AML; n = 25), chronic myeloid leukemia (CML; n = 21), chronic lymphocytic leukemia (CLL; n = 18), polycythemia vera (PV; n = 16), or myelodysplastic syndromes (MDS; n = 13) were analyzed before and in 19 patients after ex vivo expansion in the presence of multiple cytokines (kit ligand, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor plus erythropoietin). Compared with hematopoietic progenitor cells from normal donors (n = 108), telomerase activity (TA) was increased 2- to 5-fold in chronic phase (CP)-CML, CLL, PV, and MDS. In AML, accelerated phase (AP) and blastic phase (BP)-CML, basal TA was 10- to 50-fold higher than normal. TA of CP-CML CD34+ cells was up-regulated within 72 h of ex vivo culture, peaked after 1 week, and decreased below detection after 2 weeks. In contrast, TA in AP/BP-CML and AML CD34+ cells was down-regulated after 1 week of culture and decreased further thereafter. The expansion potential of CD34+ cells from patients with leukemia was considerably decreased compared with CD34+ cells from normal donors. The average expansion of cells from leukemic individuals was 6.5-, 2.3-, 0.6-, and 0.2-fold in weeks 1, 2, 3, and 4, respectively, whereas expansion of normal cells was 5- to 15-fold higher. In serial expansion culture, a median telomeric loss of 0.7 kbp was observed during 3-4 weeks of expansion. Our results demonstrate that up-regulation of telomerase is similar in CD34+ cells from CP-CML, CLL, PV, and MDS patients and in normal hematopoietic cells during the first week of culture, whereas in AML and AP/BP-CML, telomerase is high at baseline and down-regulated during expansion culture. High levels of telomerase in leukemic progenitors at baseline may be a feature of both the malignant phenotype and rapid cycling. Telomerase down-regulation during culture of leukemic cells may be due to the decreased expansion potential or repression of normal hematopoiesis, or in AML it may be due to the partial differentiation of AML cells, shown previously to be associated with loss of TA. Telomere shortening during ex vivo expansion correlated with low levels of TA, particularly in chronic leukemic and MDS progenitors where telomerase was insufficient to protect against telomere bp loss during intense proliferation.
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PMID:Telomerase activity and telomere length in acute and chronic leukemia, pre- and post-ex vivo culture. 1067 44

Wilms' tumor gene WT1 mRNA is a new marker of leukemic blast cells for AML, ALL, and CML. Minimal residual disease(MRD) of leukemia can be detected at frequencies as low as 1 in 10(3) to 10(4) normal bone marrow cells and 1 in 10(5) normal peripheral blood mononuclear cells by means of the quantitation of WT1 mRNA(WT1 assay) using reverse transcriptase-polymerase chain reaction. Thus, the WT1 assay makes it possible to rapidly assess the effectiveness of treatment and to evaluate the degree of eradication of leukemic cell in individual leukemia patients. Furthermore, WT1 assay can continuously assess the disease progression of myelodysplastic syndromes(MDS) and predict the evolution of MDS to overt AML within 6 months.
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PMID:[Genetic diagnosis of leukemia: diagnosis of relapse and complete remission, and prediction of leukemia onset]. 1080 19

The studies described here demonstrate that in vitro processing of cells before extraction of RNA has a major effect on the number and type of cytokine transcripts present within MDS and leukemia cells. Transcripts for GM-CSF, a cytokine whose production by leukemia cells is believed to play an important role in the pathogenesis of leukemia, was not detectable in 12/13 unprocessed AML specimens, in 12/12 MDS specimens, or in 7/7 CML specimens but once detected in many specimens after processing. These data strongly suggest that leukemia cell production of GMCSF rarely occurs in vivo.
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PMID:Cytokine production by in vitro processed and unprocessed haematopoietic cells. 1088 Feb 62

Myeloablation and immunosuppression were considered to be the two major roles of the conditioning regimens for allogeneic stem cell transplantation to facilitate engraftment. It has turned out, however, that immunosuppression is more important and myeloablation is not necessary for engraftment. At the same time, it is considered that the major anti-tumor effect of allogeneic stem cell transplantation depends on the graft-versus-leukemia effect, not on the conditioning regimen itself. In patients with CML who relapsed after allogeneic transplantation, for example, infusion of donor lymphocytes can induce a second complete remission. Non-myeloablative stem cell transplantation (NST) was developed in the late 90s based on these theories. Low-dose, less toxic, so-called "non-myeloablative" preparative regimens have been designed not to eradicate the malignancies, but to provide sufficient immunosuppression to allow donor cells to engraft, while the graft-versus-malignancy effects eradicate the tumor. This strategy permits allogeneic transplantation to be used in patients who are not eligible for conventional, often myeloablative, transplantation because of advanced age or organ dysfunction. Non-myeloablative preparative regimens contain purine analogs, such as fludarabine or cladribine. The NST regimen being used at the National Cancer Center Hospital, Tokyo, Japan, consists of cladribine (0.11 mg/kg x 6 days), busulfan (4 mg/kg x 2 days) and rabbit anti-thymocyte globulin (2.5 mg/kg x 4 days). We enrolled 6 patients in this NST protocol so far: 1 with severe aplastic anemia (sibling-PBSCT), 2 with MDS-RA (1 for sibling-PBSCT and 1 for matched uBMT), 1 with AML-CR2 (matched uBMT), 1 with AML-CR3 (sibling-PBSCT), and 1 with relapsed AML (mismatched related PBSCT). All patients achieved engraftment within 14 days with complete donor chimerism. In addition to leukemias, a graft-versus-malignancy effect was also reported in allogeneic NST of solid tumors, such as renal cell carcinoma and malignant melanoma. The long-term efficacy of NST remains to be determined, and further clinical trials are warranted.
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PMID:[Non-myeloablative stem cell transplant]. 1089 4

Peripheral blood stem cell transplants (PBSCT) from unrelated donors (n = 37) were compared with bone marrow transplants (BM, bone marrow group, n = 37) in a matched pair analysis. Ten patients (2, class 1) in the alloPBSCT group and seven patients (2, class 1) in the BM group had one HLA locus mismatch donor, respectively. The following factors were matched: HLA-compatibility, diagnosis, disease stage, age and gender. The median age in the PBSC group was 37 years (19-56, excluding one 6-year-old child) and in the BM group 37 years (18-53). The BM group consisted of 12 females and 25 males, 17 females and 20 males were in the PBSC group. Twelve patients in the BM and 11 patients in the PBSC group were diagnosed with AMI,; 7/7, ALL; 15/15, CML; 2/3, MDS; 1/1, NHL. Thirty-four (14/20) of the 74 patients (45%) were considered as high risk patients. The conditioning regimen was BU/CY for standard risk patients with myeloid diseases (31 patients) and TBI/CY for ALL and NHL patients (36 patients); six patients received intensified conditioning with VP16 (2 patients), thiotepa (2 patients) or melphalan (1 patient). The GVHD prophylaxis regimen was used according to the Seattle protocol. DFS was 51% (19 patients) with a median of 352 days and 59% (21 patients) with a median of 760 days, in PBSC and BM transplants, respectively. The median time to leukocyte engraftment in PBSC patients was 14 days (range 6-26 days) and in the BM group 19 days (range 9-29 days; P < 0.02). The time of platelet engraftment did not differ significantly between the groups. The incidence of grade II-IV acute GVHD was 40% (four patients died, 13%) in the PBSC group and 20)% (three patients died, 8%) in the BM group, respectively (P < 0.05, log-rank). No signs of aGVHD were found in 19% of the patients in the PBSC and 27% in the BM group. Our results indicate that allogeneic PBSCT does lead to a significantly faster leukocyte engraftment. The significant increase with regard to the incidence and shorter time of onset of severe aGVHD in PBSC patients, compared to marrow transplant patients, need to be confirmed in a randomised trial.
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PMID:A comparative study of peripheral blood stem cell vs bone marrow transplantation from unrelated donors (MUD): a single center study. 1093 83


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