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)

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

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

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

There are several common themes that are emerging from our expanding knowledge about the inherited bone marrow failure syndromes. Patients have a spectrum of birth defects, which are relatively characteristic for each syndrome. but overlap in features such as poor growth. radial ray anomalies, and involvement of skin, eyes, renal, cardiac, skeletal, and other organs. Within each syndrome the composition and severity of the physical phenotype varies widely, and it may require the astute observer to make the correct diagnoses in the milder cases. There is also a wide spectrum to the hematologic picture. These range from single cytopenias such as DBA, SCN, and TAR, which do not develop pancytopenia, to SD and Amega patients who begin with deficiency of a specific single lineage, but evolve to aplastic anemia, to patients with FA or DC, who may present with a deficiency of any one of the cell lines, but almost inevitably end up with full-blown aplastic anemia. Acute myeloid leukemia has been observed in FA, DBA, DC, SD, SCN, and Amega, although not yet in TAR patients. MDS has also been reported in all of the same disorders as AML, although whether it is a preleukemic condition or an independent bone marrow dyspoiesis is not yet clear. Solid tumors are also now appearing in patients whose underlying disease involves hematopoiesis and physical development. These tumors occur at much younger ages than in the general population, in patients who do not appear to have the usual risk factors, and have patterns that are characteristic to the syndrome, such as head and neck and gynecologic cancers in FA and DC, and osteogenic sarcomas in DBA. The other syndromes have not yet been reported to have a propensity for solid tumors. Several genes have been identified that are mutant in some of the syndromes, although the pathophysiology is still not entirely clear. The inheritance patterns include X-linked recessive, autosomal dominant, autosomal recessive, and even mitochondrial. The FA gene products appear to cooperate, and are important in the pathways involved in response to DNA damage. However, the role of this pathway in developmental defects, hematopoietic failure, and the specific malignancies in FA is not fully elucidated. The DC gene products are important for maintenance of telomere length, which may have relevance to development of aplastic anemia and malignancies, but the relation to the physical phenotype is less apparent. The role of mutations in c-mpl in Amega is more straightforward. since the gene codes for the receptor for thrombopoietin. which is the hormone required for megakaryocyte and platelet development; patients with mutant c-mpl do not have birth defects. The role of mutations in RPS19 in erythropoiesis or developmental defects in DBA patients is not obvious, and the increased frequency of osteogenic sarcomas suggests that at least that subset of patients may have a mutant tumor suppressor gene (such as p53, the mutant gene in Li-Fraumeni syndrome) [68]. Although patients with SCN have mutations in neutrophil elastase, patients with similar mutations may have relatively benign cyclic neutropenia, or may even have normal neutrophil levels [69,70]. The mitochondrial gene deletions in Pearson's Syndrome result in variable degrees of acidosis, and varied organ involvement due to heteroplasmy. Thus, the disorders included under the rubric "inherited bone marrow failure syndromes" have clinical. hematologic, oncologic, and genetic diversity.
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PMID:Bone marrow failure syndromes in children. 1243 Jun 21

The development of mature blood cell from hematopoietic stem cells is regulated by transcription factors that coordinate the expression of lineage-specific genes. GATA transcription factors are zinc finger DNA-binding proteins that play crucial roles in various biological processes, including hematopoiesis. Among GATA family proteins, GATA-1, GATA-2, and GATA-3 are essential for hematopoiesis. GATA-1 functions to promote development of erythrocytes, megakaryocytes, eosinophils, and mast cells. Mutations in GATA-1 are associated with acute megakaryoblastic leukemia (AMKL), congenital erythroid hypoplasia (Diamond-Blackfan anemia; DBA), and X-linked anemia and/or thrombocytopenia. Conversely, GATA-2 functions early in hematopoiesis and is required for maintenance and expansion of hematopoietic stem cells (HSCs) and/or multipotent progenitors. GATA-2 mutations are associated with immunodeficiency, lymphedema, myelodysplastic syndrome (MDS), and leukemia. Furthermore, decreased GATA-2 expression may contribute to the pathophysiology of aplastic anemia. GATA-3 has an important role in T cell development, and has been suggested to be involved in the pathophysiology of acute lymphoblastic leukemias. This review summarizes current knowledge on hematological disorders associated with GATA-1 and GATA-2 mutations.
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PMID:GATA Transcription Factors: Basic Principles and Related Human Disorders. 2856 65