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Query: UMLS:C0002874 (aplastic anemia)
 5,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Magnetic resonance imaging (MRI) has value in characterizing normal and abnormal bone marrow because of its ability to distinguish fat from other tissues. Due to this advantage, hematologic disorders resulting in alterations of the normal cellular and fatty marrow distribution can be appreciated. In this article, the role of MRI in diffuse hematologic disorders is emphasized. At birth, almost all marrow is cellular, but by age 25, cellular marrow is restricted to the axial skeleton and proximal femoral and humeral metaphysis. The remainder is fatty, consisting of 80% fat, 15% water, and 5% protein. With increased need for hematopoiesis, reconversion from fatty to cellular marrow occurs in many diffuse disease states. Diffuse diseases that affect bone marrow production are divided into four categories representing conditions that affect the pluripotent hematopoietic stem cell. These include stem cell failure resulting in aplastic anemia, uncontrolled stem cell proliferation as exemplified by polycythemia vera, stem cell dysplasia such as sickle cell anemia, and malignant transformations or replacement. The MRI appearance of these disorders is discussed in this article. The use of spin-echo (SE) sequences is the most common approach to bone marrow imaging. With T1-weighted SE images, fatty marrow will appear bright and cellular marrow, with lower fat content, will exhibit a lower density signal. With T2-weighted SE pulse sequences, contrast between fatty marrow and cellular marrow decreases. Contrast between fatty and cellular marrow is enhanced with chemical shift imaging, including Dixon out-of-phase imaging, as emphasized in this article. MRI presents a more global view of the bone marrow than biopsy material and should provide a better understanding of diffuse hematologic disease progression and resolution.
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PMID:Magnetic resonance imaging of bone marrow: diagnostic value in diffuse hematologic disorders. 220 May

Danazol was administered to two patients with paroxysmal nocturnal hemoglobinuria (PNH) with a dramatic effect on the hematological findings. The patients, 31- and 41-year-old females, were initially diagnosed as having aplastic anemia, and were initially treated with anabolic steroid and immunosuppressive therapy, respectively. Sugar water and Ham tests turned positive at the start of danazol therapy in the former patient and after two months in the latter patient. This drug produced a dramatic improvement in the hemoglobin level and the platelet count and showed few side effects in the patients. A possible mechanism of action of danazol for PNH is briefly discussed.
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PMID:Danazol treatment for paroxysmal nocturnal hemoglobinuria. 227 26

In inbred mice strain DBA/2, genetically controlled differences in aryl hydrocarbon hydroxylase (AHH) activity have been demonstrated that predispose to aplastic anemia. To test the hypothesis of a similar mechanism in humans, we studied the formation of benzo(a)pyrene DNA adducts and water-soluble metabolites in skin fibroblasts from eight patients with aplastic anemia and eight normal controls. The ratio of water-soluble metabolites and DNA adducts was 46.5 +/- 16.6 in patients and was significantly lower as compared to 82.9 +/- 38.5 in controls (P less than 0.05). We conclude that increased formation of genotoxic intermediates may be a pathogenetic mechanism in some patients with aplastic anemia.
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PMID:Increased formation of DNA adducts in cultured fibroblasts of patients with aplastic anemia after in vitro incubation with benzo(a)pyrene. 228 25

Paroxysmal nocturnal hemoglobinuria (PNH) is a complex stem cell disorder and its occurrence in childhood is quite uncommon. A 6-year-old girl with pancytopenia was presented. There is no nocturnal hemoglobinuria or other symptoms of chronic hemolysis. Bone marrow examination revealed mild hypocellularity initially, and a tentative diagnosis of aplastic anemia was made. This patient received conventional therapy with uneventful course. Two consecutive episodes of hemolytic transfusion reaction were noted and positive sugar water test and Ham,s test lead the clue of PNH. The literature on the clinical manifestation, pathogenesis, diagnosis and management of PNH is reviewed briefly.
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PMID:Paroxysmal nocturnal hemoglobinuria: report of one case. 263 13

Fifteen adult patients undergoing allogeneic bone marrow transplantation (BMT) received cyclosporine (CSP) as prophylaxis of graft versus host disease (GVHD). In our patients eleven were hematologic malignancies, and four were severe aplastic anemia. Twelve patients were HLA-matched, and three were one locus mismatched. Three patients received CSP only, twelve received CSP and short term methotrexate. Seven patients had acute GVHD, but GVHD over Grade II were seen in only 3 patients who were transplanted from HLA-one locus mismatched donor. 7 patients had chronic GVHD. CSP were given intravenously at 3-5 mg/kg, starting 1 day before BMT. From about day 30, CSP was given orally. CSP concentrations when patients were given orally were lower in patients who had chronic GVHD. Although hypertension and water retention were seen in 8 patients, and renal dysfunction was seen in 3 patients, the side effects of CSP were mild and transient. There were no correlations between serum concentrations and the side effects of CSP. Three patients had the disturbance of hematopoiesis. Ten of fifteen patients are alive at median follow-up of 18.5 months (8-41 months) after BMT.
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PMID:[Cyclosporine as prophylaxis for graft versus host disease in adults undergoing allogeneic bone marrow transplantation]. 267 37

Twenty-one in vivo studies of bone marrow of the lumbar spine were performed with a 0.6-T commercial MR imager and proton chemical shift imaging techniques. Six healthy volunteers served as controls. Multiple measurements in the volunteers demonstrated reproducibility within errors of 5% for fat fraction and 6% for T1 of water. Ten patients who had histologically proved leukemia or aplastic anemia were then examined. The data show that changes in fat fraction represent the underlying reason for many of the changes observed in conventional spin-echo (SE) images of these disorders. Although both conventional and chemical shift images showed differences among the pathologic groups and healthy volunteers, fat fraction determined with chemical shift imaging was the single best discriminator among them. A two-point estimate of fat fraction was also evaluated. This rapid imaging protocol performed almost as well as the complete quantitative analysis in discriminating between pathologic and healthy tissue and showed improved discrimination compared with conventional SE techniques.
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PMID:Hematologic bone marrow disorders: quantitative chemical shift MR imaging. 318 3

During a 2-week period three unrelated children presented with severe aplastic anaemia at a general hospital serving a population of 25,000 children aged 0-15 years. The probability of this occurring by chance alone was 0.00009 (exact probability cluster analysis). Serology for common viral infections including hepatitis A & B and infectious mononucleosis was negative. It was not possible to demonstrate IgM antibodies to human parvovirus (HPV) by radioimmunoprecipitation or HPV virions by DNA hybridization in the patients or any members of their families. Epidemiological investigation failed to demonstrate a common environmental toxin. It did reveal, however, that all three patients had spent time, within the preceding 3 months in a swimming pool and its surrounding area in a region of Cardiff where none of them resided. Pool maintenance was satisfactory and water analysis showed no abnormality. The possibility must remain that the cluster was caused by an undisclosed environmental toxin.
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PMID:A cluster of three cases of aplastic anaemia in children. 336 32

Four patients with severe aplastic anemia were treated with a combination of cyclosporin (5 mg/kg/day) and steroids (prednisone 0.2-0.8 mg/kg/day 3/4 days). A positive response (transfusions stopped, granulocytes greater than 1500/mm3, thrombocytes greater than 50,000/mm3) was achieved in three of these patients. The therapy had a rapid effect on reticulocytes and granulocytes (7-14 days) while platelet numbers took longer to correct (2-4 months). All patients presented signs of dyserythropoiesis with macrocytosis. Side effects of therapy were minor (tremor, water retention, gynecomastia, hirsutism). In this series, the combination of cyclosporin with steroids appears to be an effective treatment for severe aplastic anemia with a more rapid result and better tolerance in comparison to antilymphocyte serum.
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PMID:[Treatment of severe aplastic anemia with a cyclosporin-corticosteroid combination]. 342 63

Serial magnetic resonance (MR) studies of the cervical bone marrow were performed in five patients undergoing bone marrow transplantation for chronic granulocytic leukemia and in four patients with aplastic anemia who were treated with antilymphocytic globulin. Findings were compared with those from a group of healthy volunteers. Chemical shift imaging techniques were used to exploit the presence of protons in fat and water in the red marrow. Characteristic changes were seen in aplastic anemia before treatment, but derivation of images representing fat and water fractions was necessary to distinguish leukemic marrow. Acute changes during the treatment of leukemia may reflect the effects of chemotherapy and radiation therapy, whereas changes in the chronic phase of both diseases may prove useful in predicting treatment outcome. MR studies are likely to be useful in the assessment and treatment of hematologic disorders.
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PMID:Bone marrow in leukemia and aplastic anemia: MR imaging before, during, and after treatment. 354 34

Benzene is one of the world's major commodity chemicals. It is derived from petroleum and coal and is used both as a solvent and as a starting material in chemical syntheses. The numerous industrial uses of benzene over the last century need not be recounted here, but the most recent addition to the list of uses of benzene is as a component in a mixture of aromatic compounds added to gasoline for the purpose of replacing lead compounds as anti-knock ingredients. The best known and longest recognized toxic effect of benzene is the depression of bone marrow function seen in occupationally exposed individuals. These people have been found to display anemia, leucopenia, and/or thrombocytopenia. When pancytopenia, i.e., the simultaneous depression of all three cell types, occurs and is accompanied by bone marrow necrosis, the syndrome is called aplastic anemia. In addition to observing this decrease in humans and relating it to benzene exposure, it has been possible to establish animal models which mimic the human disease. The result has been considerable scientific investigation into the mechanism of benzene toxicity. Although the association between benzene exposure and aplastic anemia has been recognized and accepted throughout most of this century, it is only recently that leukemia, particularly of the acute myelogenous type, has been related to benzene. The acceptance of benzene as an etiological agent in aplastic anemia in large measure derives from our ability to reproduce the disease in most animals treated with sufficiently high doses of benzene over the necessary time period. Unfortunately, despite extensive efforts in several laboratories, it has not been possible to establish a reproducible, reliable model for the study of benzene-induced leukemia. The recent demonstration that several animals exposed to benzene either by inhalation or in the drinking water during studies by Drs. B. Goldstein and C. Maltoni suggests that such a model may be forthcoming. Nevertheless, at this time it is not clear whether bone marrow damage of the type that leads to aplastic anemia is required for the development of leukemia. Most studies of benzene toxicity have involved dosing animals with benzene either by inhalation or by injection, using high doses to ensure a toxic response. Very few studies have concentrated on the oral route of administration and none have concentrated on administering benzene by mouth at the low doses occasionally detected in drinking water.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Chemical of current interest--benzene. 359 Feb 6


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