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a precursor of leukocytes that normally occurs only in bone marrow

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/04/17 21:29:36」(JST)

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The myeloblast is a unipotent stem cell, which will differentiate into one of the effectors of the granulocyte series.

Origin

These cells descend from the primitive reticulum cells, which are found in the stroma of the marrow. There is also an intermediate phase between the myeloblast and these primitive reticulum cell, namely the hemocytoblast. At this time several developing blood cell lines are available, like erythropoiesis and thrombopoiesis. The granulopoiesis is regulated by humoral agents, like colony-stimulating factor (CSF) and interleukin 3.

Location in the body

Human Myeloblasts

The myeloblasts reside extravascularly in the marrow. The hematopoiesis takes place in the extravascular cavities between the sinuses of the marrow. The wall of the sinuses is composed of two different types of cells, the endothelial cells and the adventitial reticular cells. The hemopoietic cells are aligned in cords or wedges between these sinuses, the myeloblasts and other granular progenitors are concentrated in the subcortical regions of these hemopoietic cords.

Structure

Myeloblasts are rather small cells with a diameter between 14 and 18μm. The major part is occupied by a large oval nucleus composed of very fine nonaggregated chromatin and possesses 3 or more nucleoli. The cytoplasm has basophilic character and is devoid of granules, which is a major difference with its successor, the promyelocyte. The nucleolus is the site of assembly of ribosomal proteins, which are located in various particles dispersed over the cytoplasm. Mitochondria are present but have a rather small size.

The main features that distinguish a myeloblast from a lymphoblast upon microscopic examination are the presence of more prominent nucleoli, the nuclear chromatin being less condensed, and cytoplasmic granules are present.^[1]

Function

A comprehensive diagram of human hematopoiesis

The granulopoiesis consists of 5 stages, of which the myeloblast is the first recognizable cell. Next in the differentiation sequence is the promyelocyte, which can develop into one of the three different precursor cells: neutrophilic, basophilic or eosinophilic myelocytes. This proliferation needs five divisions before the final stage is obtained. These divisions all take place in the first three stages of granulopoiesis.

Pathology

The most common problem with malfunctioning myeloblasts is acute myeloblastic leukemia.^[2]^[3] The main clinical features are caused by failure of the hemopoiesis with anemia, hemorrhage and infection as result. There is a progressive accumulation of leukemic cells, because some blast progenitor cells renew themselves and will have a limited differentiated division. Sometimes acute myeloblastic leukemia can be initiated by earlier hematologic disorder, like myelodysplastic syndrome, pancytopenia, or hypoplasia of the bone marrow.

References

^ Figure 12-14 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson. Robbins Basic Pathology. Philadelphia: Saunders. ISBN 1-4160-2973-7. 8th edition.
^ Murohashi I., Tohda S., Suzuki T., Nagata K., Yamashita Y., Nara N.(1989).Autocrine growth mechanisms of the progenitors of blast cells in acute myeloblastic leukemia. Journal of the American Society of Hematology 74, 35-41
^ Villamor N., Zarco M-A., Rozman M., Ribera J-M., Feliu E., Montserrat E.(1998).Acute myeloblastic leukemia with minimal myeloid differentiation: phenotypical and ultrastructural characteristics. Leukemia 12, 1071–1075

Wilson J.D., Braunwald E., Isselbacher K.J., Martin J.B., Fauci A.S., Root R.K. Harrison’s Principles of Internal Medicine 12th edition. McGraw-Hill Inc.(1991).
Curran R.C., Crocker J. Curran’s Atlas of Histopathology 4th edition. Harvey Miller Publishers LTD. Oxford University Press Inc.(distributor).(2000).
Bloom W., Fawcett D.W. A Textbook of Histology 12th edition. W.B. Saunders Company
News and views.(1949).Journal of the American Society of Hematology 4, 89-96
Williams Majorie J.(1955).Myeloblastic Leukemia Preceded by Prolonged Hematologic Disorder. Journal of the American society of hematology 10, 502-509
Beutler E.,Lichtman M.,Coller B.,Kipps T. Williams Hematology 5th edition. McGraw-Hill Inc.(1995).

UpToDate Contents

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1. 末梢血塗抹標本の評価 evaluation of the peripheral blood smear
2. 急性骨髄性白血病の臨床症状、病理学的特徴、および診断 clinical manifestations pathologic features and diagnosis of acute myeloid leukemia
3. 急性骨髄性白血病の分類 classification of acute myeloid leukemia
4. 骨髄異形成症候群の臨床症状および診断 clinical manifestations and diagnosis of the myelodysplastic syndromes
5. 骨髄穿刺塗抹標本の評価 evaluation of bone marrow aspirate smears

English Journal

Differences in blast immunophenotypes among disease types in myelodysplastic syndromes: A multicenter validation study.

Ogata K, Kakumoto K, Matsuda A, Tohyama K, Tamura H, Ueda Y, Kurokawa M, Takeuchi J, Shibayama H, Emi N, Motoji T, Miyazaki Y, Tamaki H, Mitani K, Naoe T, Sugiyama H, Takaku F.SourceDivision of Hematology, Department of Medicine, Nippon Medical School, Tokyo, Japan.
Leukemia research.Leuk Res.2012 Oct;36(10):1229-36. Epub 2012 Jun 7.
We conducted a multicenter, flow cytometry study to validate differences in immunophenotypes among disease types in melodysplastic syndromes (MDS). The data obtained from 115 patients were combined into three groups according to disease grade, i.e., low-grade MDS, refractory anemia with excess blast
PMID 22682984

Augmented Macrophage Differentiation and Polarization of Tumor-associated Macrophages Towards M1 Subtype in Listeria-administered Tumor-bearing Host.

Rai RK, Vishvakarma NK, Mohapatra TM, Singh SM.Source*Department of Microbiology, Institute of Medical Sciences †School of Biotechnology, Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
Journal of immunotherapy (Hagerstown, Md. : 1997).J Immunother.2012 Aug 13. [Epub ahead of print]
This study investigates the effect of Listeria administration on differentiation of macrophages from precursor bone marrow cells and functional status of tumor-associated macrophages (TAM). Listeria administration not only resulted in an augmented infiltration of tumor by F4/80 macrophages but also
PMID 22892451

Japanese Journal

急速な経過を辿ったPure Erythroid Leukemia

石塚保弘,小澤真一,深澤元晴
千葉医学雑誌 88(5), 207-211, 2012-10-01
… 入院時WBC 2,600/μl,Myeloblast 4 %,Hb 5.2 g/dl,Plt 1.8×104/μl,LDH 10,026 IU/l。 …
NAID 120004943924

The Mitotic-Arresting and Apoptosis-Inducing Effects of Diosgenyl Saponins on Human Leukemia Cell Lines(Pharmacology)

LIU Ming-Jie,WANG Zhao,JU Yong,ZHOU Jiang-bing,WANG Yu,WONG Ricky Ngok-Shun
Biological & pharmaceutical bulletin 27(7), 1059-1065, 2004-07-01
… In a previous report, we showed that dioscin was able to induce cytotoxicity and apoptosis in human myeloblast leukemia HL-60 cells. …
NAID 110003608913

Related Pictures

Myeloblast - Wikipedia MLT1265 Cell Identification - StudyBlue Blasts 101 - StudyBlue Myeloblast : Highest N/C ratio - Finest nuclear chromatin pattern ||| Promyelocyte Myeloblast with Auer rod Exam 3 - Hematology 3910 with Dr. Jator at Austin Peay State University - StudyBlue [ACUTE MYELOGENOUS LEUKEMIA, M1, BLOOD]. The defining feature of a myeloblast is fine Myeloblast | definition of myeloblast by Medical dictionary

★リンクテーブル★

リンク元	「骨髄芽球」「granulocyte precursor cell」「myeloblastic」
拡張検索	「acute myeloblastic leukemia」「acute myeloblastic leukemia with maturation」「acute myeloblastic leukemia, with granulocytic maturation」