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

Electron microscopy of erythropoiesis in aplastic anaemia has demonstrated some unique features of dyserythropoiesis at the ultrastructural level, which contribute to understanding of the morphological features which are seen in the light microscope. The findings provide further evidence for the presence of qualitative defects in erythropoiesis in aplastic conditions. The alterations seen included bi- and multinucleated cells, intercellular bridges containing microtubules, internuclear chromatin bridges, irregular nuclear shapes, juxta-nuclear and peripheral cisternal structures, ringed sideroblasts, a diversity of intranuclear inclusions, nuclear clefts in both eu- and heterochromatin, and a variety of anomalies of the nuclear membrane. The significance of the occurrence of these anomalies in aplastic anaemia is considered and the role of the nuclear membrane and of endoplasmic reticulum in the pathogenesis of aplastic anaemia is discussed.
 ...
PMID:The ultrastructure of dyserythropoiesis in aplastic anaemia. 119 64

Acetanilide like phenylbutazone is paraoxidized by the liver endoplasmic reticulum as a primary biotransformation step. Both compounds were given at different times to each of 10 healthy volunteer subjects and the plasma disappearances measured. Correlation was shown between plasma clearance values of the two compounds (r = + 0.7067; P < 0.05).Eight patients with hypoplastic anaemia after phenylbutazone therapy were investigated. Plasma clearance values and half lives of acetanilide were measured in this group of patients and compared with those of a group of 30 healthy volunteer controls. There was a significant decrease in clearance (P < 0.01) and lengthening of half lives (P < 0.001 in the patients with phenylbutazone-associated hypoplasia. Five patients with idiopathic aplastic anaemia-that is, without history of antecedent phenylbutazone ingestion-were similarly investigated with acetanilide and there was no significant difference between the results in these patients and those in the control group.It is suggested that relatively poor paraoxidation of phenylbutazone producing high blood concentrations on a given dose may be a factor responsible for the drug-associated hypoplasia even though it does not explain the similar pattern of adverse reactions reported in association with oral administration of the metabolite oxyphenbutazone.
 ...
PMID:Acetanilide oxidation in phenylbutazone-associated hypoplastic anaemia. 441 15

Benzene is a well-known environmental pollutant that can induce hematotoxicity, aplastic anemia, acute myelogenous leukemia, and lymphoma. However, although benzene metabolites are known to induce oxidative stress and disrupt the cell cycle, the mechanism underlying lympho/leukemogenicity is not fully understood. Caspase-4 (alias caspase-11) and -12 are inflammatory caspases implicated in inflammation and endoplasmic reticulum stress-induced apoptosis. The objectives of this study were to investigate the altered expression of caspase-4 and -12 in mouse bone marrow after benzene exposure and to determine whether their alterations are associated with benzene-induced bone marrow toxicity, especially cellular apoptosis. In addition, we evaluated whether the p53 gene is involved in regulating the mechanism, using both wild-type (WT) mice and mice lacking the p53 gene. For this study, 8-week-old C57BL/6 mice [WT and p53 knockout (KO)] were administered a benzene solution (150 mg/kg diluted in corn oil) via oral gavage once daily, 5 days/week, for 1 or 2 weeks. Blood and bone marrow cells were collected and cell counts were measured using a Coulter counter. Total mRNA and protein extracts were prepared from the harvested bone marrow cells. Then qRT-PCR and Western blotting were performed to detect changes in the caspases at the mRNA and protein level, respectively. A DNA fragmentation assay and Annexin-V staining were carried out on the bone marrow cells to detect apoptosis. Results indicated that when compared to the control, leukocyte number and bone marrow cellularity decreased significantly in WT mice. The expression of caspase-4 and -12 mRNA increased significantly after 12 days of benzene treatment in the bone marrow cells of benzene-exposed p53KO mice. However, apoptosis detection assays indicated no evidence of apoptosis in p53KO or WT mice. In addition, no changes of other apoptosis-related caspases, such as caspase-3 and -9, were found in WT or p53KO mice at the level of mRNA and proteins. These results indicated that upregulation of caspase-4 and -12 in mice lacking the p53 gene is not associated with cellular apoptosis. In conclusion, caspase-4 and -12 can be activated by benzene treatment without inducing cell apoptosis in mouse bone marrow, which are partly under the regulation of the p53 gene.
 ...
PMID:Benzene activates caspase-4 and -12 at the transcription level, without an association with apoptosis, in mouse bone marrow cells lacking the p53 gene. 1932 98

Aplastic anemia (AA) and myelodysplasia (MDS) are forms of bone marrow failure that are often part of the same progressive underlying disorder. While most cases are simplex and idiopathic, some show a clear pattern of inheritance; therefore, elucidating the underlying genetic cause could lead to a greater understanding of this spectrum of disorders. We used a combination of exome sequencing and SNP haplotype analysis to identify causative mutations in a family with a history of autosomal-dominant AA/MDS. We identified a heterozygous mutation in SRP72, a component of the signal recognition particle (SRP) that is responsible for the translocation of nascent membrane-bound and excreted proteins to the endoplasmic reticulum. A subsequent screen revealed another autosomal-dominant family with an inherited heterozygous SRP72 mutation. Transfection of these sequences into mammalian cells suggested that these proteins localize incorrectly within the cell. Furthermore, coimmunoprecipitation of epitope-tagged SRP72 indicated that the essential RNA component of the SRP did not fully associate with one of the SRP72 variants. These results suggest that inherited mutations in a component of the SRP have a role in the pathophysiology of AA/MDS, identifying a third pathway for developing these disorders alongside transcription factor and telomerase mutations.
 ...
PMID:Exome sequencing identifies autosomal-dominant SRP72 mutations associated with familial aplasia and myelodysplasia. 2254 60

Autoimmune response targeting the hematopoietic stem cells highlights the current understanding of acquired aplastic anemia (AAA) pathogenesis. Upregulation of the unfolded protein response is the cell's rejoinder to a variety of stresses, which either result in restoring homeostasis or cell death by increased expression of the transcription factor C/EBP homologous protein. We hypothesized that there is an inherent increased sensitivity to various cellular stressors, including the ones that target endoplasmic reticulum (ER) in AAA leading to a decreased proliferation and potentially contributing to susceptibility to autologous cytotoxicity. Using archived bone marrow aspirate samples, we demonstrate that the culture-expanded AAA myeloid cells have an increased response to ER stress induced by tunicamycin leading to decreased cell proliferation. Within the AAA myeloid samples, we show that the disease status, active versus response to therapy at the time of sampling does not alter the ER stress response. This is the first report, which provides evidence for an inherent defective stress control in the myeloid cells as a possible mechanism of evolution of the disease process in AAA.
 ...
PMID:Evidence for Increased Response to Induced Endoplasmic Reticulum Stress in Myeloid Cells in Acquired Aplastic Anemia. 2833 39