title: An in situ study of CD34(+) cells in human fetal bone marrow.
abstract: The purpose of this study was to characterize the spatial distribution, number and size of CD34(+) cells in fetal bone marrow. Thin sections of normal fetal bone marrow from lumbar vertebrae were stained using CD34 antibody QBend/10. Sections were used under light microscopy with various eyepiece graticules to make measurements of CD34(+) cells in situ. Results showed that at mid- and late gestation, approximately 2% and 0.5% of fetal bone marrow cells were CD34(+) respectively. The mean distance of CD34(+) cells from the nearest trabecular bone surface was 61 +/- 4 and 46 +/- 4 microm, respectively, for mid- and late gestation. The mean distance to the nearest neighbour was 46 +/- 5 and 105 +/- 15 microm, and the mean distance to the nearest blood vessel was 13 +/- 1 and 17 +/- 2 microm respectively. The concentration of CD34(+) cells in the peripheral region was 6.5 times greater than that at the centre of the sections. Overall, the percentage number of CD34(+) cells decreased with gestational age. The cellular and nuclear diameters of CD34(+) cells remained unchanged throughout mid- and late gestation at 5.4 +/- 0.1 and 3.8 +/- 0.1 microm respectively. This information will be used to calculate the natural background alpha-radiation dose to haemopoietic stem cells.
authors.affiliation: H. H. Wills Physics Laboratory, University of Bristol, Bristol, UK. janet.allen@bris.ac.uk
authors.forename: J E
authors.initials: JE
authors.lastname: Allen
authors.forename: D L
authors.initials: DL
authors.lastname: Henshaw
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D001853:Bone Marrow / Q000196:embryology* / Q000648:ultrastructure; D002452:Cell Count; D005865:Gestational Age; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008159:Lumbar Vertebrae; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000196:embryology
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers