Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The wide clinical range of CMPD can be understood as leukaemia of pluripotent stem cells according to the pathogenic concepts reviewed above. Blastic metamorphoses of CMPD are regressions to a more primitive level of cellular differentiation. The predominant proliferative cell line characterizes the classical entities of PV, PT and CML, and their different prognoses. Pure erythrocytic and megakaryocytic proliferations are more compatible with sustained physiologic bone marrow functions than granulocytic proliferations. The combinations of granulocytic and megakaryocytic growth are especially prone to develop MF/OMS, in which participation of immune reactions, of granulocytic and of platelet factors is probable. An etiologic role for ineffective thrombocytopoiesis is supported by experimental as well as by histologic evidence. Myelofibrosis and osteomyelosclerosis may have similar causes, but develop independently. The prevalence of the female sex among thrombocythaemic patients was proven statistically also for the increase of giant type megakaryocytes in the form of clusters in the bone marrow, and for longer median survival of females in CMPD, especially when there is megakaryocytosis in the bone marrow. It is assumed that females may be better protected against the detrimentous effects of abnormal platelet production. An arbitrary classification according to haematologic and histologic criteria was applied to PV, PT and CML, and groups with typical and atypical haematologic and histologic signs were distinguished. The latter cannot be separated from each other by their various haematologic manifestations, but by histology and their different propensity to progress into more immature and/or fibrotic stages. Three major groups are characterized by histology: mixed granulocytic-megakaryocytic myelosis with giant megakaryocytic clusters, a similar variant with diffuse distribution of giant megakaryocytes, and immature and/or pleomorphic megakaryocytic myelosis. Transitions from each of these groups have been observed as well as transitions from each of the typical CMPD-entities into these less typical forms. CML, frequently accompanied by dwarf-megakaryocytes, often develops into pleomorphic megakaryocytic or blastic myelosis. Blastic dedifferentiation and myelofibrosis manifest themselves as closely related end stages, to which principally all groups proceed after a longer or shorter period of time, modified by the proliferating cell lines in each group. Clinical, experimental and histologic evidence of this natural history has been reviewed, with special emphasis on the re-evaluation of technically optimal bone marrow biopsies of untreated patients.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Chronic myeloproliferative disorders (CMPD). 639 25

A series of 101 consecutive patients with chronic myeloproliferative disorders including polycythaemia vera, chronic myelogenous leukaemia, idiopathic myelofibrosis and essential thrombocythaemia have been studied. The aim was to establish the incidence of thrombotic and haemorrhagic complications and the possible role played by platelet number and function. The total incidence of haemostatic complications was 21% and the platelet functional tests investigated (platelet aggregation, generation of malondialdehyde, endogenous serotonin, beta-thromboglobulin and platelet coagulant activity) were of little help for predicting these clinical complications.
 ...
PMID:Thrombohaemorrhagic complications in 101 cases of myeloproliferative disorders: relationship to platelet number and function. 658 Jan 71

A consecutive series of patients (1978-1981) comprising all patients with acute leukaemia from a population of 475000 inhabitants was reviewed. Thus, 94 patients were diagnosed as having acute leukaemia. No patients were lost from follow-up. The incidence figures of ALL and AML differed significantly from those of Sweden as a whole. 9 patients were less than 15 years old. The median age of adult patients was 64 years, 60.8% being greater than or equal to 60 years old. Of adult patients with AML, 20% had a preleukaemic history (chronic myeloproliferative disorders, myelodysplastic syndromes and others). None of 6 patients with leukaemia as a metamorphosis of a chronic myeloproliferative disorder achieved a complete remission. The overall remission rate of the remaining adult patients was 25%. Treated patients, 15-39 years old, with AML without any preleukaemic history, had a complete remission rate of 80% compared to 12% for patients greater than or equal to 60 years old with the same diagnosis. Of 60 patients with 'primary' AML, 14 were not treated, mainly because of advanced age and complicating diseases. Most of these patients died within a week of admission.
 ...
PMID:Acute leukaemia in a defined geographic area--incidence, clinical history and prognosis. 659 86

A retrospective study was performed to examine the natural course of uncontrolled thrombocytosis associated with chronic myeloproliferative disorders. Thirty-eight patients with polycythaemia rubra vera (PV), myelofibrosis/myeloid metaplasia (MM), chronic myelogenous leukaemia (CML) or essential thrombocythaemia (ET) had platelet counts greater than 1000 X 10(9)/1 and were followed closely for a total of 246 patient years. Eleven of the patients experienced haemorrhagic episodes. Bleeding was twice as frequent in patients over 59 years old as in those younger and no bleeding occurred in those less than 51 years of age. There was no correlation between frequency of bleeding and extent of thrombocytosis. Bleeding events occurred concurrently with use of anti-inflammatory agents in 32% of episodes. The gastrointestinal tract was the most frequent site. Documented thrombotic events occurred in three patients, two of whom had PV with haematocrits greater than 53%. This study suggests that the thrombocytosis of myeloproliferative processes may pose a less serious threat than originally thought and that aggressive lowering of the platelet count may not be indicated in all cases.
 ...
PMID:Uncontrolled thrombocytosis in chronic myeloproliferative disorders. 697 93

The c-mpl gene encodes a member of the hematopoietic cytokine receptor superfamily. This gene was discovered through the study of a murine retrovirus which induces an acute myeloproliferative syndrome in mice. MPLV (for myeloproliferative leukemia virus) has transduced a truncated and constitutively activated form of the c-mpl receptor chain. The c-mpl ligand is unknown, but recent data indicate that it could specifically regulate thrombocytopoiesis. This review focuses on the expression of the c-mpl gene in a large series of human hematopoietic pathologies by Northern blot analysis. Barely detectable transcript levels were detected in normal bone marrow (BM) and in BM samples from chronic myeloproliferative disorders, plasmocytoma, Burkitt lymphoma or acute lymphoid leukemia. In contrast, high levels of c-mpl expression were detected in 45% of acute myeloid leukemia (AML). No correlation was found between c-mpl expression and the French-American-British classification subtype of AML. However c-mpl expression correlated with CD34 expression, and unfavorable cytogenetic abnormalities, defining a subgroup of AML with a low rate of complete remission. In myelodysplasia, c-mpl expression was elevated in 44% of chronic myelomonocytic leukemia (CMML), 42% of refractory anemia with excess myeloblasts (RAEB), and RAEB in transformation to acute leukemia (RAEBt), but not in refractory anemia (RA) and RA with ringed sideroblasts (RARS). In CMML, there was no correlation between c-mpl expression and any prognostic factor tested, nor with the course of the disease. The biologic significance of c-mpl expression in RAEB and RAEBt is probably different.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:c-mpl expression in hematologic disorders. 777 60

Platelet abnormalities are common in patients with chronic myeloproliferative disorders. In this study we report abnormalities in platelets morphology and function in 45 patients with chronic myeloproliferative disorders: 15 with chronic myelogenous leukaemia (CML), 8 with polycythemia rubra vera (PRV), 20 with essential thrombocythemia, and 2 with myelofibrosis (ME). We investigated flow cytometric features of platelets as measured with Technicon H1 technology, VIZ, mean platelet volume (MPV), plateletocrit), platelet distribution width (PDW), and modal platelet volume (PLT Mode) Platelet aggregation in response to ADP, epinephrine and collagen was used as functional test. In patients with ET, PRV and MF we found a significant decrease in platelet volume (both MPV and PLT MODE). Decrease in platelet aggregation and secretion in response to ADP, epinephrine and collagen was the most frequent abnormality in platelets function and was observed in most of patients with thrombocythemia in chronic myeloproliferative disorders.
 ...
PMID:[Platelet defects in chronic myeloproliferative disorders]. 799 98

We have investigated the involvement of tumor suppressor genes (p53 and RB1) and dominantly acting oncogenes (Ras family genes) in BCR/ABL positive and negative chronic myeloproliferative disorders (CMPD) at different stages of the disease, including 26 cases of BCR/ABL+ chronic myeloid leukemia (CML) blast crisis, 9 myelosclerosis with myeloid metaplasia, 4 polycythemia vera, 10 essential thrombocythemia, 1 juvenile CML, and 8 BCR/ABL- CML. The presence of mutations in p53 exons 5 through 9, as well as in RB1 exons 10-27 and in N-, K-, H-Ras exons 1 and 2 was tested by the PCR-Single Strand Conformation Polymorphism technique and by PCR-Direct Sequencing. In addition, Southern blot analysis was used to investigate the occurrence of gross rearrangements in the p53 gene as well as loss of heterozygosity at 17p13, the site of p53. Acute phase BCR/ABL-CMPD cases displayed a high frequency of p53 (2/7) and Ras (3/7) lesions, whereas BCR/ABL- CMPD in chronic phase displayed only germline p53 and Ras sequences. Conversely, p53 inactivation was restricted to only 1/26 cases of BCR/ABL+ CML blast crisis. No alterations in the RB1 gene were detected in any of the cases analyzed. These data indicate that p53 inactivation and/or Ras activation might play a role in acute transformation of BCR/ABL- CMPD and that the molecular mechanisms of tumor progression may be different in BCR/ABL+ versus BCR/ABL-CMPD.
Leukemia 1994 Apr
PMID:Molecular mechanisms of tumor progression in chronic myeloproliferative disorders. 815

We have investigated the involvement of the p53 tumor suppressor gene and RAS family proto-oncogenes in BCR/ABL-negative chronic myeloproliferative disorders (CMPD), including nine cases of myelosclerosis with myeloid metaplasia, four polycythemia vera, 10 essential thrombocythemia, one juvenile chronic myeloid leukemia, and eight BCR/ABL-negative chronic myeloid leukemia. Twenty-five samples were studied in the chronic phase, while seven samples were analyzed in the acute accelerated or blastic phase. The presence of mutations in p53 exons 5-9, as well as in N-, K-, H-Ras exons 1 and 2 (containing codons 12, 13, and 61) was tested by the polymerase chain reaction (PCR) single strand conformation polymorphism technique and by PCR direct sequencing. In addition, restriction analysis was performed to screen for gross rearrangements within the p53 locus. Alterations of the p53 tumor suppressor gene and Ras family proto-oncogenes were detected in 2/7 and 3/7 cases of acute phase BCR/ABL-negative CMPD, respectively, while consistently negative in all the chronic phase samples analyzed. These results suggest that p53 inactivation and/or Ras activation might play a role in acute transformation of BCR/ABL-negative CMPD.
Leukemia 1993 Jul
PMID:Mutations in the P53 and RAS family genes are associated with tumor progression of BCR/ABL negative chronic myeloproliferative disorders. 832 Oct 46

Similar to two other hematopoietic growth factor receptors, the c-fms (macrophage colony-stimulating factor receptor) and the c-kit genes, c-mpl has been discovered through the study of oncogenic retroviruses. Unlike c-fms and c-kit, which both belong to a subgroup of tyrosine kinase receptors, the c-mpl proto-oncogene encodes a new member of the cytokine receptor superfamily. We have studied the expression of c-mpl in a series of 105 patients with hematologic malignancies using Northern blot analysis. The levels of c-mpl transcripts in lymphoid malignancies and in chronic myeloproliferative disorders were not significantly different from those found in normal bone marrow cells, in which c-mpl was barely detectable. In contrast, c-mpl expression was increased in 26 of 51 patients with acute myeloblastic leukemia (AML) and in 5 of 16 patients with myelodysplastic syndromes. Amplification of the c-mpl gene was detected in genomic DNA of one M4 AML patient. There was no significant correlation between c-mpl expression and the French-American-British classification of AML. Patients with high c-mpl expression appeared to belong to a subgroup of AML with a low rate of complete remission and a poor prognosis, including secondary leukemia and AML with unfavorable cytogenetic abnormalities.
 ...
PMID:Expression of the c-mpl proto-oncogene in human hematologic malignancies. 839 55

We report two patients who had been initially diagnosed as having a myelodysplastic syndrome but subsequently progressed into a leukothrombocytosis state which mimicked a chronic myeloproliferative disorder. Both patients had anemia and mild neutropenia without thrombocytopenia at the time of their diagnosis of myelodysplastic syndrome, and dyshematopoietic features were present in the bone marrow. After treatment with vitamin D3 for 7 and 18 months, respectively, they developed leukothrombocytosis which responded to hydroxyurea. We speculate that these and other similar patients with this unusual course might constitute an entity distinct from the typical myelodysplastic syndromes or chronic myeloproliferative disorders.
Leukemia 1993 Feb
PMID:Myelodysplastic syndrome evolving into a myeloproliferative disorder: one disease or two? 815 71


<< Previous 1 2 3 4 5 6 7 Next >>