megaloblast

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megaloblast

 [meg´ah-lo-blast″]
a large, nucleated immature progenitor of an abnormal erythrocytic series, an abnormal counterpart to the normoblast; megaloblasts are present in the blood in certain anemias. adj., adj megaloblas´tic.

meg·a·lo·blast

(meg'ă-lō-blast'),
A large, nucleated, embryonic type of cell that is a precursor of erythrocytes in an abnormal erythropoietic process observed in pernicious anemia; a megaloblasts four stages of development are as follows: 1) promegaloblast, 2) basophilic megaloblast, 3) polychromatic megaloblast, 4) orthochromatic megaloblast.
See also: erythroblast.
[megalo- + G. blastos, + germ, sprout]

megaloblast

(mĕg′ə-lō-blăst′)
n.
An abnormally large nucleated red blood cell found especially in people having pernicious anemia or certain vitamin deficiencies.

meg′a·lo·blas′tic adj.

megaloblast

An enlarged erythroblast (erythrocyte precursor) with an enlarged nucleus, which arises in a background of vitamin B12 and/or folic acid deficiency and is characterised by asynchronous nucleocytoplasmic development, and manifest by delayed or incomplete nuclear maturation relative to cytoplasmic development; haemoglobinisation proceeds normally, while nuclear maturation slows as the maturation-dependent methyl precursors—usually provided by vitamin B12 and folic acid—are not present.

meg·a·lo·blast

(meg'ă-lō-blast)
A large, nucleated, embryonic type of cell that is a precursor of erythrocytes in an abnormal erythropoietic process observed in pernicious anemia; a megaloblast's four stages of development are: 1) promegaloblast, 2) basophilic megaloblast, 3) polychromatic megaloblast, and 4) orthochromatic megaloblast.
See also: erythroblast
[megalo- + G. blastos, germ, sprout]

Megaloblast

A large erythroblast (a red marrow cell that synthesizes hemoglobin).
Mentioned in: Anemias
References in periodicals archive ?
Megaloblastic anaemia and aplastic anaemia are important causes of pancytopenia in India.
Other conditions causing pancytopenia 9 (19.6%), included two cases of megaloblastic anemia and one each of myelodysplastic syndrome, aplastic anemia, systemic lupus erythematosus, Rosai-Dorfman syndrome, malaria, toxoplasmosis, and sickle cell anemia.
Thalassemic syndromes Heterozygous beta thalassemia Other hemoglobinopathies Artifact in the presence of Hb S Some Hb variants with thalassemic phenotype Acquired conditions Megaloblastic anemia Hyperthyroidism Pseudoxanthoma elasticum Hypertrophic osteoarthropathy Treatment-related conditions Antiretroviral therapy in patients with HIV
While megaloblastic picture was present only in 1 (1.75%) patient.
In summary, we report an 18-year-old male patient who presented with myelopathy without megaloblastic anemia with highly increased MMA, tHcy, and slightly reduced concentrations of vitamin [B.sub.12] from vitamin [B.sub.12] deficiency caused by [N.sub.2]O abuse.
Hicks, "Apoptosis in megaloblastic anemia occurs during DNA synthesis by a p53-independent, nucleoside-reversible mechanism," Blood, vol.
Megaloblastic anemia is a common early symptom leading to diagnosis, although neurological symptoms may occur in the absence of hematological abnormalities.[4,5] Although vitamin B12 cutoff values vary for each laboratory, serum values of less than 200 pg/mL is defined as vitamin B12 deficiency.
Oval macrocytosis (Figure 2--Slide B) is seen in megaloblastic anaemias, myelodysplasia and drugs such as hydroxyurea [31].
Peripheral Vascular Disease, DVT and Pulmonary Embolism, Hepato Cellular Carcinoma, DCLD, Abdominal tuberculosis, Inflammatory Bowel Disease, Malabsorption, Acute Hepatitis, Enteric Fever, Pulmonary tuberculosis, Leptospirosis, Leukemia, Lymphoma, Myelopoliferative Disorders, Hemophilia, Aplastic Anemia, Hemolytic Anemia, Megaloblastic Anemia, Iron Deficiency Anaemia, Acute Kidney Injury, Chronic Renal Failure, Glumeronephritis, Cushing's Syndrome and Diabetes Mellitus.
[12,14] Also, since the CHr is calculated from the reticulocyte MCV, patients with haemoglobinopathy associated with microcytosis will have a falsely low CHr, while patients with megaloblastic anaemia or macrocytic indices (MCV >100 fl), including some patients on antiretroviral therapy, will have a falsely elevated CHr.
Other associated complications of GT are malabsorption related, which include protein-losing enteropathy, iron deficiency anemia, and megaloblastic anemia.
Results: Out of 157 patients, 30 patients (19.1%) had leukemia, 26 (16.6%) had megaloblastic anemia, ITP was present in 26 patients (16.6%), 18 patients (11.5%) showed normal bone marrow, 17 patients (10.8%) had evidence of hemolytic anemia, aplastic anemia was present in 9 patients (5.7%), iron deficiency anemia was seen in 9 patients (5.7%), anemia of chronic disorder was present in 08 patients (5.1%), hypersplenism was present in 05 patients (3.2%), metastatic lesions, PNH and visceral leishmaniasis was present in 2 patients (1.3%) each.