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

A patient with subacute eosinophilic leukemia is presented, with full recognition of the controversy surrounding that entity. Serum vitamin B12 and B12-binding protein studies and simultaneous complete blood counts were done before and during 6 months of high-dose, intermittent combination chemotherapy. The patient presented with extremely high levels of serum vitamin B12, unsaturated B12-binding capacity, and transcobalamin I, all of which resembled the highest values seen in chronic myelogenous leukemia. Serial studies, during and after remission induction, showed a precipitous fall of serum vitamin B12 and unsaturated B12-binding capacity to normal levels. The data show that transcobalamin I levels, which eventually reached low-normal range, correlate best with the level of circulating and bone marrow eosinophils. Transcobalamin II and serum third binder appeared to be normal throughout the patient's course. The B12-binding protein abnormalities are not considered diagnostic of eosinophilic leukemia.
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PMID:Serum vitamin B12-binding proteins in a case of eosinophilic leukemia. 6 Jun 95

The clinical, hematologic and histologic characteristics of six patients with refractory anemia with deletion of the long arm of chromosome No. 5 are described. These patients had a distinct hematologic picture with macrocytic anemia of mild to moderate severity, normal to low leukocyte count and increased platelet count. The long arm of chromosome No. 5 was deleted in the majority of bone marrow metaphases. The main cause of anemia was underproduction with decreased erythroid precursors in the bone marrow and no increase in peripheral blood reticulocytes. Two of five patients responded transiently to the administration of androgens. In vitro evaluation of the bone marrow growth pattern in semisolid agar culture system was performed in three patients and was found to be normal and distinct from that in patients with preleukemia. In a follow up of up to five years, no patient had changed hematologically and in none had leukemia developed. The 5q-syndrome is a distinct hematologic entity and probably more common than hitherto realized. This diagnosis may have therapeutic and prognostic implications.
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PMID:Macrocytic anemia, thrombocytosis and nonlobulated megakaryocytes: the 5q-syndrome, a distinct entity. 45 27

A patient with acute myelomegakaryocytic leukemia (AMMgL), which developed from myelodysplastic syndrome (MDS) after chemotherapy against complicated small cell lung cancer, is reported. The patient was a 66 year-old male, who first presented with moderate macrocytic anemia. Bone marrow aspiration showed absolute erythroid hypoplasia and morphological abnormalities were found in erythroid, granuloid and megakaryocytic lineage cells. Iron utilization studies using radioisotope showed ineffective hematopoiesis. He was diagnosed as having MDS (refractory anemia) and treated with prednisolone, fluoxymesterone, and transfusions. After 3 years, small cell lung cancer was found, but he achieved complete remission with chemotherapy. Since then, pancytopenia progressed with myelofibrosis. Abnormal blasts were found in peripheral blood and gradually increased. He finally died from a blastic crisis resulting in gastric bleeding. The blasts were peroxidase negative, platelet peroxidase positive (10%), and glycoprotein II b/III a antibody positive, indicating megakaryoblasts.
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PMID:[Acute myelomegakaryocytic leukemia developed from myelodysplastic syndrome after chemotherapy against complicated small cell lung cancer]. 164 8

Transcobalamin II (TC II) is essential for cellular uptake of cobalamin. However, the origin of this transport protein is controversial and many organ sources have been suggested. We studied human umbilical vein endothelial cells cultured in vitro. The cells contained TC II (2.3 pmol/10(8) cells) and released progressively increasing amounts of the protein into the surrounding medium during the 3-day incubation period. This release exceeded the starting intracellular content of TC II. In contrast, endothelial cells did not contain or elaborate R binder, the other major circulating binding protein for cobalamin, Cycloheximide inhibited the elaboration of TC II, suggesting that the endothelial cells synthesize the protein. Thrombin, which stimulates tissue plasminogen activator release, did not enhance TC II release, and neither did endotoxin or mellitin. However, thrombin did appear to partially protect TC II release from inhibition by cycloheximide. Among other cells studied, human fibroblasts also released TC II into the incubation medium, while K562 human leukemia cells, ARH-77 and HS Sultan human plasma cell lines, and Raji strain lymphoblasts did not. The data suggest that endothelial cells are an important source of the metabolically crucial TC II.
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PMID:Human umbilical vein endothelial cells secrete transcobalamin II. 210 63

Plasma membrane receptors for the serum cobalamin-binding protein transcobalamin II (TCII) were identified on human leukemia K562 and HL-60 cells using immunoaffinity-purified human TCII labeled with [57Co]cyanocobalamin. The Bmax values for TCII receptors on proliferating K562 and HL-60 cells were 4,500 and 2,700 per cell, respectively. Corresponding dissociation constants (kd) were 8.0 x 10(-11) mol/L and 9.0 x 10(-11) mol/L. Rabbit TCII also bound to K562 and HL-60 cells but with slightly reduced affinities. Calcium was required for the binding of transcobalamin II to K562 cells. Brief treatment of these cells with trypsin resulted in almost total loss of surface binding activity. After removal of trypsin, surface receptors for TCII slowly reappeared, reaching pretrypsin treatment densities only after 24 hours. Reappearance of receptors was blocked by cycloheximide. TCII receptor densities on K562 and HL-60 cells correlated inversely with the concentration of cobalamin in the culture medium. This suggests that intracellular stores of cobalamin may affect the expression of transcobalamin receptors. Nonproliferating stationary-phase K562 cells had low TCII receptor densities (less than 1,200 receptors/cell). However, the density of TCII receptors increased substantially when cells were subcultured in fresh medium. Up-regulation of receptor expression coincided with increased 3H-thymidine incorporation, which preceded the resumption of cellular proliferation as measured by cell density. In the presence of cytosine arabinoside, which induces erythroid differentiation, K562 cells down-regulated expression of TCII receptors. When HL-60 cells were subcultured in fresh medium containing dimethysulfoxide to induce granulocytic differentiation, the up-regulation of TCII receptors was suppressed. This event occurred well before a diminution of 3H-thymidine incorporation and cessation of proliferation. Thus, changes in the regulation of expression of TCII receptors correlate with both the proliferative and differentiation status of cells.
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PMID:Expression of transcobalamin II receptors by human leukemia K562 and HL-60 cells. 216 22

A case of chronic myelogenous leukemia (CML) of 10-year survival in described. A 44-year old male was admitted to our hospital because of general malaise, abdominal fullness and fever in February, 1977. On physical examination, giant splenomegaly and hepatomegaly were detected. Peripheral blood examination revealed leukocytosis without hiatus leukemia , normochromic macrocytic anemia and thrombocytosis. NAP rate and score were 16% and 22. Cytogenetic analysis of PB without stimulator revealed 46, XY, Ph1. Then he was diagnosed as having a typical type of Ph1-positive CML. He had been successfully treated over 9 years by intermittent administration of busulfan. However, anemia suddenly progressed in February, 1986 followed by leukopenia and thrombocytopenia. Hemorrhage was not detected by the examination. Though he had been received blood transfusion, the anemia progressed rapidly. He was died of cachexia on 4th of August, 1987. The postmortem examination revealed bone marrow aplasia with no signs of blast crisis nor myelofibrosis. Secondary hemochromatosis was seen in the liver, spleen, pancreas and some other organs.
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PMID:[Bone marrow aplasia without blast crisis in a case of CML of 10-year survival]. 279 87

Simultaneous addition of uniform latex particles derivatized with transferrin (0.532 micron) and transcobalamin II (0.345 micron) to leukemia L1210 cells resulted in segregated binding to individual microvilli as demonstrated by scanning electron microscopy. This segregated distribution suggests that individual microvilli are endowed either transferrin or transcobalamin II receptors but not both. Intracellular sorting and segregation of newly synthesized or recycling receptors probably occur prior to expression on the plasmalemma microvilli.
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PMID:Receptors for transferrin and transcobalamin II display segregated distribution on microvilli of leukemia L1210 cells. 303 92

A 40-year-old woman presented with splenomegaly, macrocytic anemia, and red cell aplasia. Although lymphocytosis was absent in the peripheral blood, large atypical lymphoid aggregates were present in the bone marrow. Splenectomy resulted in partial remission of red cell aplasia, but a gradual increase in the number of peripheral blood lymphocytes followed during the next 36 months. Flow cytometric analysis demonstrated that the majority of these peripheral blood lymphocytes had suppressor, natural killer T-cell phenotype. No other treatment was given until red cell hypoplasia worsened 42 months after initial presentation. Repeat bone marrow evaluation again demonstrated severe erythroid hypoplasia and large abnormal lymphocytic infiltrates. Cyclophosphamide given for 8 months resulted in complete resolution of the red cell aplasia and complete clinical remission of CLL. However, flow cytometric analysis revealed persistent increase in bone marrow T-cells, and bone marrow co-culture studies demonstrated residual ability of peripheral blood mononuclear cells to inhibit erythropoiesis in vitro, suggesting that residual, clinically undetectable leukemia persists in spite of complete clinical remission.
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PMID:T-cell chronic lymphocytic leukemia with pure red cell aplasia: laboratory demonstration of persistent leukemia in spite of apparent complete clinical remission. 308 88

Refractory macrocytic anemia with hypolobulated megakaryocytic nuclei and partial deletion of the long arm of chromosome 5 has been termed the 5q- syndrome. Although long survival has been reported in a few cases of 5q- refractory anemia, accumulating evidence suggests that this syndrome is a preleukemic state with risk of transformation to acute nonlymphocytic leukemia as well as complications of bone marrow failure. This report describes the first apparently successful therapy for this disorder in a young man who originally presented with a clinical picture consistent with pure red cell aplasia and normal marrow chromosomes but with hypolobulated megakaryocytic nuclei. He was treated with vitamins, androgens, and sequential trials of immunosuppressive therapy, all without response. Two years after diagnosis, repeated marrow cytogenetic studies showed a 5q- abnormality in 70 percent and later in 100 percent of marrow metaphases. Because of transfusion-induced hemosiderosis and the availability of a cytogenetically normal monozygotic twin, bone marrow transplantation was undertaken. In light of the clonal (and suspected preleukemic) nature of the 5q- syndrome, the patient's marrow was ablated with a busulfan plus cyclophosphamide regimen used for patients with nonlymphocytic leukemia. Sustained engraftment of cytogenetically normal marrow ensued. Two years after transplantation, and following six months of regular phlebotomy, the patient was hematologically normal with a normal serum ferritin level.
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PMID:Hematologic and cytogenetic remission of 5q-refractory anemia after syngeneic bone marrow transplantation. 308

This paper analyzes the hematologic features and outcome of 13 patients with chromosome 5 abnormalities (monosomy 5 or deletion of 5q), either isolated or with additional anomalies. Among four patients with isolated del (5q), two had a stable refractory macrocytic anemia with thrombocytosis (5q-syndrome). All nine patients with complex karyotypes had acute leukemia or refractory anemia with excess of blasts in acute transformation; two cases were TdT-positive, with a lymphoid or a mixed phenotype. In seven patients, preleukemia preceded overt leukemia, and in six, a prior therapeutic, or occupational exposure to mutagens/carcinogens had occurred. Additional chromosome 7 abnormalities were seen in four cases. The median survival of patients with complex karyotypes was 19 months from the time of diagnosis of the hematologic disorder and 5 months from the time of identification of the chromosome 5 abnormality. Pathogenetic implications of the chromosome 5 monosomy or del (5q) through a proto-oncogene activation and the putative hemopoietic stem cell involvement in a clonal disease are discussed.
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PMID:Hematologic and clinical features of patients with chromosome 5 monosomy or deletion (5q). 335 40


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