Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002874 (aplastic anemia)
 5,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fetal-like erythropoiesis frequently accompanies marrow stress conditions such as Diamond-Blackfan syndrome and aplastic anemia. In contrast, patients with transient erythroblastopenia of childhood have erythrocytes which lack fetal characteristics at the time of diagnosis. This report describes nine children with transient erythroblastopenia of childhood in whom transient, fetal-like erythropoiesis was observed during the period of recovery. These patients initially presented with anemia, reticulocytopenia, erythrocytes of normal size for age, low levels of fetal hemoglobin, and i-antigen. During the recovery period, however, erythrocytes manifested one or more fetal characteristics. These included an increased fetal hemoglobin (in three of five patients), the presence of i-antigen (in four of six patients), and macrocytosis (in seven of nine patients). These fetal characteristics persisted more than 2 wk after the reticulocyte count returned to normal. Within one year from diagnosis, red blood cells contained no fetal characteristics.
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PMID:Fetal-like erythropoiesis during recovery from transient erythroblastopenia of childhood (TEC). 725 49

Oral exposure of DBA/2 mice to benzo[a]pyrene (BP) has been shown to result in hematotoxicity which is manifested as aplastic anemia and leukemia. Since normal hematopoiesis is regulated by bone marrow stromal cells, in this study we have characterized the bone marrow stromal toxicity induced by BP and BP-derived metabolites, particularly quinones. Incubation of stromal cells with various concentrations of BP-1,6-, 3,6-, 6,12-, or 7,8-quinone for 24 hr resulted in a significant decrease of cell survival in a concentration-dependent manner, while cells treated with BP or BP-7,8-dihydrodiol did not exhibit any significant loss of cell survival. Among the BP quinones examined, BP-1,6-quinone was the most cytotoxic to stromal cells. The cytotoxicity induced by BP-1,6-quinone also exhibited a time-dependent relationship. Pretreatment of stromal cells with 1,2-dithiole-3-thione (D3T) resulted in a significant induction of both cellular reduced glutathione (GSH) content and quinone reductase (QR) activity in a concentration-dependent manner. However, D3T pretreatment did not offer any protection against BP-1,6-quinone-induced toxicity. Furthermore, dicumarol, a potent inhibitor of QR, or buthionine sulfoximine, a specific inhibitor of GSH biosynthesis, did not potentiate BP-1,6-quinone-induced cytotoxicity was not altered. However, incubation of stromal cells with BP-1,6-quinone resulted in a significant depletion of cellular ATP content and mitochondrial morphological changes, which preceded the loss of cell survival. In addition to BP-1,6-quinone, other cytotoxic BP quinones also exhibited a capacity to deplete cellular ATP level in stromal cells, while BP, which was not cytotoxic to stromal cells, did not elicit any significant decrease in cellular ATP level. These observations suggest that mitochondria may be a potential target of BP quinones. Overall, the above results indicate that neither cellular GSH and QR nor reactive oxygen species appear to be involved in BP quinone-induced stromal cell injury and that BP quinones may elicit cytotoxicity to stromal cells through directly disrupting mitochondrial energy metabolism.
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PMID:Characterization of benzo[a]pyrene quinone-induced toxicity to primary cultured bone marrow stromal cells from DBA/2 mice: potential role of mitochondrial dysfunction. 753 Aug 64

Transplantation of allogeneic bone marrow (BM) is often complicated by the development of acute graft-vs-host disease (GVHD) caused by contaminating T cells in BM inocula because of activation of the host reactive T effector cells. Using a murine model for acute GVHD caused by injection of parental C57Bl/6 splenocytes into unirradiated (C57Bl/6 x DBA/2) F1 hybrids, we demonstrated that pretreatment of the inocula with a novel immunosuppressant, B subunit of cholera toxin (CT-B) impaired the ability of C57Bl/6 T cells to induce acute GVHD in F1 recipients. F1 mice injected with CT-B-treated C57Bl/6 splenocytes did not develop significant splenomegaly, and no antihost CTLs were found in their spleens. Moreover, these mice did not suffer from aplastic anemia, nor from general immunosuppression. Immunofluorescence studies suggest that treatment of the inducing inocula with CT-B selectively prevents accumulation of the host-reactive CD8+ T cells in F1 mice. Furthermore, our experiments demonstrated that CT-B treatment does not impair the ability of BM progenitors to form colonies in semisolid culture or in lethally irradiated hosts. Thus, taken together, our data suggest that ex vivo CT-B treatment can be used in allogeneic BM transplantation to prevent acute GVHD.
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PMID:Prevention of acute graft-versus-host disease by treatment with a novel immunosuppressant. Cholera toxin B subunit. 789 40

We investigated the effect of the human ligand for flt-3 (FL) on the committed progenitor colony formation of normal bone marrow (BM) (n = 9) and BM from four aplastic anaemia (AA) and three Diamond-Blackfan anaemia (DBA) patients. Methylcellulose committed progenitor cell assays were carried out using FL alone and in combinations with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) and c-kit ligand (KL). FL alone had a limited, though significant, effect on the production of granulocyte-macrophage colony-forming unit (CFU-GM) colonies from normal BM and showed an additive effect with IL-3 and GM-CSF separately, but not in combination. FL did not increase the stimulation of KL and did not have an effect on the production of erythroid progenitor colonies. FL had no effect on the AA and DBA BMs studied.
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PMID:The effect of human flt-3 ligand on committed progenitor cell production from normal, aplastic anaemia and Diamond-Blackfan anaemia bone marrow. 855 52

Frequencies of spontaneously occurring and X-ray induced, stable and unstable types of chromosome aberrations in peripheral blood lymphocytes from two groups of radiosensitive patients, i.e., aplastic anemia (AA) and Diamond-Blackfan anemia (DBA), were determined. Two types of staining methods, i.e., chromosome painting with two cocktails of chromosome-specific DNA libraries (Nos. 1, 3, X and Nos. 2, 4 and 8), as well as conventional Giemsa staining, were employed. Chromosome painting was done with single and multicolor fluorescence in situ hybridization (FISH). The frequencies of spontaneously occurring chromosome aberrations in AA and DBA patients were not significantly different from healthy individuals. Hypersensitivity to X-rays was seen both in G0 as well as in G2 phase of the cell cycle in lymphocytes from AA and DBA patients, confirming our earlier findings using micronucleus (DBA) and G2 radiosensitivity (AA) assays.
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PMID:X-ray-sensitivity of lymphocytes of aplastic- and Diamond-Blackfan-anemia patients as detected by conventional cytogenetic and chromosome painting techniques. 904 4

The role of known hematopoietic growth factors in the pathogenesis of aplastic anemia and congenital hypoplastic anemia has been extensively studied and no evidence has been obtained that deficiency of these factors contributes to the hypoproliferative state in these disorders. Clonal hematopoiesis seems to be present at least in a small percentage of cases of aplastic anemia, a finding that needs further investigation. Androgens were shown to be beneficial only for women with aplastic anemia treated with antilymphocyte globulin. Unrelated-donor bone marrow transplantation is becoming a realistic approach for children and very young adults with aplastic anemia, but in older groups the survival is very poor. New observations on abnormalities of lymphokines and cytokines in Fanconi's anemia have been described, but their pathogenetic significance remains unknown. A large number of studies have excluded the possibility that abnormalities of c-kit/SCF genes and their expression are responsible for the erythroid aplasia in Diamond-Blackfan syndrome. Cyclosporine was found to be an effective treatment for pure red cell aplasia associated with chronic lymphocytic leukemia. The cell membrane receptor for B19 parvovirus has been identified as the P antigen. Long-term studies showed that in 20% of patients with homozygous sickle cell disease, infection by B19 does not cause erythroid aplasia.
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PMID:Aplastic anemia and pure red cell aplasia. 937 Dec 75

Fas ligand (FasL) is a membrane protein that is expressed in activated T cells and natural killer cells. FasL binds to Fas on target cells and induces apoptosis. There exists a soluble form of FasL (sFasL), and sFasL also induces apoptosis of Fas-bearing cells. The serum sFasL concentrations were reported to be elevated in patients with large granular lymphocytic leukemia and natural killer cell lymphoma. In this study, we have measured serum sFasL concentrations in other hematological disorders, including severe aplastic anemia (SAA), hemophagocytic lymphohistiocytosis (HLH), and Diamond-Blackfan anemia (DBA). The serum sFasL concentration of age-matched healthy controls was 0.16 +/- 0.11 ng/mL (mean +/- SD, n = 22). The serum sFasL levels in the patients with HLH and DBA were 3.75 +/- 3.82 (n = 19; P < .0001, HLH v control) and 2.76 +/- 2.43 ng/mL (n = 6; P = .012, DBA v control), respectively. Serum interferon-gamma concentration was elevated in the patients with HLH (1.61 +/- 2.62 ng/mL) but not in those with DBA (below the detectable level). These results suggest that the Fas-FasL system plays a role, at least in part, in the pathophysiology of HLH and DBA.
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PMID:Elevation of the serum Fas ligand in patients with hemophagocytic syndrome and Diamond-Blackfan anemia. 953 89

Inherited bone marrow failure syndromes (BMFs) comprise at least one-fourth of children with aplastic anemia, and perhaps up to 10% of adults. The most common syndrome is Fanconi's anemia (FA), with more than 1,000 reported cases. FA is autosomal recessive, with birth defects in approximately 75% of patients. It is a DNA repair syndrome, diagnosed by finding chromosomal aberrations in cells treated with clastogenic agents. The major problems in FA are, in order, aplastic anemia, leukemia, and other cancers. There are at least five complementation groups; the gene for Group C has been cloned. Carrier identification and gene therapy are beginning in families at risk for FAC mutations. Dyskeratosis congenita (DC) is primarily X-linked (at Xq28), with autosomal recessive and dominant cases as well. Patients classically have reticulated hyperpigmented skin, dystrophic nails, and mucous membrane leukoplakia. approximately 50% develop aplastic anemia, sometimes prior to the DC phenotype, and approximately 10% develop cancer. Shwachman-Diamond syndrome consists of exocrine pancreatic insufficiency with neutropenia; approximately 25% develop aplastic anemia and 5%-10% develop leukemia. Amegakaryocytic thrombocytopenia presents in infancy, and often evolves into aplastic anemia and/or leukemia. Single cytopenias include Diamond-Blackfan anemia (DBA), which is inherited pure red cell aplasia; transient erythroblastopenia of childhood; Kostmann's syndrome (KS) or infantile genetic agranulocytosis, and thrombocytopenia with absent radii in which there is neonatal thrombocytopenia and absent radii. DBA and KS, particularly the latter treated with G-CSF, may develop leukemia, and solid tumors have been reported in DBA. Treatment for the various BMFs includes bone marrow transplantation, androgens, and hematopoietic cytokines such as G-CSF. These inherited syndromes thus include various combinations of marrow failure and premalignancy.
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PMID:Aplastic Anemia, Pediatric Aspects. 1038 17

Hematopoietic stem-cell transplantation (HSCT) is an effective mode of therapy in pediatrics for the treatment of both malignant and non-malignant disorders. We compared the course of children transplanted with unrelated umbilical cord blood (UCB) to those transplanted with allogeneic sibling bone marrow (BM) for bone marrow failure syndromes. Thirteen patients with a median age of 6.3 years were transplanted for the following diseases between April 1992 and November 1997: myelodysplastic syndromes, aplastic anemia, Diamond-Blackfan anemia, myelofibrosis, paroxysmal nocturnal hemoglobinuria, osteopetrosis and dyskeratosis congenita. The stem cell source was BM in ten patients and UCB in three. We retrospectively examined the conditioning regimens, stem cell source and dose, days to engraftment, survival and complication rate to see whether there was a significant advantage in using one source over the other. The median time to an absolute neutrophil count > 500 per microL was 25 days for UCB patients and 16 days for BM patients. The median time to a platelet count > 20,000 per microL was 55 days for UCB patients and 22 days for BM patients. The 100-day mortality was 66% in UCB patients and 20% in BM patients. The overall mortality rates were 66% and 40%, respectively. Three patients died prior to engraftment. Seven patients (54%) were still alive as of May 1999 with a median follow-up of 1574 days post-transplant. The patients transplanted with BM had faster engraftment and lower rates of graft-versus-host disease, 100-day mortality and overall mortality. HLA-matched sibling BM is preferred as a source but transplantation using unrelated UCB is still an option in treating pediatric bone marrow failure syndromes.
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PMID:Hematopoietic stem-cell transplantation using unrelated cord-blood versus matched sibling marrow in pediatric bone marrow failure syndrome: one center's experience. 1056 77

With donor and recipient matched at the major histocompatibility complex (MHC) locus, peripheral lymphoid tissue transplantation can be carried out without producing a graft-versus-host reaction or graft-versus-host disease (GVHD), thus correcting profound T cell immunodeficiencies of neonatally thymectomized mice. This analysis set the stage for clinical application of bone marrow transplantation (BMT) to provide for the first time cure of a human disease. With successful BMT, we cured immunologic deficiencies of a patient with XL severe combined immunodeficiency; thereafter we were the first to employ BMT to cure aplastic anemia. BMT regularly corrects immune and hematologic deficiencies caused by fatal irradiation without producing GVHD if the bone marrow (BM) used for the transplants has been purged of postthymic T cells. Over two decades in conjunction with Ikehara et al., we have shown that lethal total body irradiation (TBI) plus allogeneic BMT prevents or cures many organ-specific and systemic experimental autoimmune diseases. Animal models successfully treated by BMT include type I diabetes in nonobese diabetes (NOD) mice, type II diabetes in insulin-insensitive, glucose intolerant, diabetes mellitus (KK/Ay) mice, and autoimmune lupus erythematosus (LE) and glomerulonephritis in New Zealand Black x New Zealand White first generation hybrid (NZB x NZW)F1 females. El-Badri extended Ildstad's original research showing a high frequency of survival with a normal functioning immune system after stable mixed chimerism is produced by mixed BMT in C57BL/6 (normal long-lived black strain) mice transplanted with T cell-depleted marrow (TCDM) from BALB/c ("normal" long-lived strain) allogeneic donors and C57BL/6 syngeneic donors. We showed that osteoblasts act as facilitator cells for allogeneic BMT and promote engraftment of allogeneic hematopoietic stem cells. Wang et al. then showed that the autoimmunities and fulminating renal disease of BXSB (C57BL x SB cross and selective lupus-like systemic autoimmunity) male mice was prevented and could be cured by transplantation using TCDM from both BALB/c (resistant) and BXSB (susceptible) strains given to BXSB recipients after lethal TBI. This treatment produced mixed BMT and a stable mixed chimerism, increased longevity, corrected all manifestations of autoimmunity, and cured fulminant glomerulonephritis in these recipients. These studies generated a new perspective on the potential usefulness of BM and stem cell transplants to cure major diseases that can possibly be treated by BMT. Mixed BMT from TCD BALB/c and BXSB mice cured autoimmunities and fulminant glomerulonephritis in BXSB mice. LE disease plus coronary vascular disease that occurs in (NZW x BXSB)F1 mice, along with idiopathic thrombocytopenic purpura, is also cured in lethally irradiated (NZW x BXSB)F1 mice by BMT from C57BL/6 donors. Furthermore, hemolytic anemia, autoimmune phenomena, and hyalinizing glomerular renal disease of New Zealand Black (NZB) mice were prevented or cured by stem cell transplants using purified stem cells from MHC-matched DBA/2 donors or NZB donors. Consequently, we reasoned that autoimmunities reside in stem cells. More recently, we found that transplants of both BM cells and bones can completely and permanently prevent otherwise highly resistant autoimmune diseases of MRL/lpr lpr mice and an autoimmune polyarthritis of NZB/Kn mice. Ildstad concluded that lethal preparative measures would not be acceptable for preparations to treat autoimmune diseases, so we now employ a gentle method for producing stable mixed chimerism described by Sharabi and Sachs to achieve mixed marrow transplantation and mixed hematopoietic chimerism. Other diseases we are approaching using this gentle manipulation include two forms of diabetes: insulin-dependent diabetes mellitus (IDDM) type I in NOD mice and non-insulin-dependent diabetes mellitus (NIDDM) type II in KK/Ay mice, atherosclerosis of apolipoprotein-E + kno
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PMID:Progress toward production of immunologic tolerance with no or minimal toxic immunosuppression for prevention of immunodeficiency and autoimmune diseases. 1083 46


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