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Prenatal diagnosis of fetal abnormality using fetal cells in maternal circulation
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Gian Carlo Di Renzo, Elena Picchiassi, Michela Centra, Giuliana Coata
In reference to phenotype, stem cells express different antigenic surface markers, but the antigen mainly expressed in several stem cells lineage is the “hematopoietic” CD34 antigen. Therefore, hematopoietic CD34+ cells are the most representative cells in stem cell population. The CD34+ antigen, an integral membrane glycoprotein of 90 to 120 kD, functions as a regulator of hematopoietic cell adhesion to stromal cells of the hematopoietic microenvironment (67,68).
Marrow Purging And Stem Cell Preparation
Published in Siegfried Matzku, Rolf A. Stahel, Antibodies in Diagnosis and Therapy, 2019
Denis C. Roy, Nadine Beauger, Martin Gyger
In addition to its expression on normal hematopoietic cells, the CD34 antigen was found to be expressed on their malignant counterparts (Krause et al., 1996). For instance, approximately 40% of cases of acute myeloid leukemia (AML) express CD34 (Civin et al., 1984; Borowitz et al., 1989; Soligo et al., 1991; Vaughan et al., 1988; Geller et al., 1990). CD34 expression can also be detected in vitro on colony-forming progenitor cells of chronic myelogenous leukemia (CML) (Silvestri et al., 1992; Katz et al., 1986). In addition, in patients with myelodysplasia, increased numbers of CD34+ cells could be used as a prognostic indicator of blast crisis (Guyotat et al., 1990). Moreover, CD34 was found to be expressed in approximately 70% of cases of childhood B-lineage ALL and in a minority of cases of T-lineage ALL (Gore et al., 1991). In patients with follicular lymphoma, bcl-2-IgH rearranged lymphoma cells were detectable in the CD34+CD19+ fraction, but rarely in the CD34+CD19— fraction (Macintyre et al., 1995).
Flow Cytometric Analysis of Human Bone Marrow
Published in Adrian P. Gee, BONE MARROW PROCESSING and PURGING, 2020
James G. Bender, Dennis Van Epps
A significant advance was made in the identification of the human stem cell population with the description of the CD34 antigen, which recognizes a small subset of cells containing the stem cells and progenitors.3,46,47 As it is difficult to measure directly the numbers of stem cells present in cell preparations that are used for transplant, the only parameters that have been correlated with reconstitution are the number of committed CFC48 and the total number of nucleated cells transplanted.49,50 Multiparameter analysis by flow cytometry is a useful approach for defining populations of cells that are at very low frequencies. A major limitation to the detection of rare cells in peripheral blood and bone marrow is the nonspecific binding of monoclonal antibodies to some cell types, and the inability to resolve adequately small numbers of positive cells from a large population of negative cells. Others have shown that detection of rare malignant cells in peripheral blood can be significantly improved by using multiple flow cytometric parameters.51 One of the problems in identifying CD34+ cells in bone marrow is the relatively low expression of CD34, causing difficulty in resolving CD34+ cells from those that do not express this antigen. This problem is intensified by the nonspecific binding of antibodies and the inherent autofluorescence of cell populations, such as monocytes and granulocytes. One solution52 has been to use the light scatter properties of low side scatter and high forward scatter to define a region known as the “blast region” to remove undesired populations and enrich for the less frequent population. This approach can detect populations as small as 0.5%. Other techniques utilize a series of depletions,53 or elutriation54 to enrich for CD34+ cells. This strategy, however, makes quantitation of the original cell population difficult. Using the multicolor strategy, described above, in which the predominant mature cells are excluded from analysis by use of a mixture of antibodies that identify mature cells can provide high resolution identification of CD34+ cells (Figure 3).
Intracellular ROS profile in hematopoietic progenitors of MDS patients: association with blast count and iron overload
Published in Hematology, 2021
Lap Shu Alan Chan, Lilly ChunHong Gu, Heather A. Leitch, Richard A. Wells
We also observed greater heterogeneity in CD34+ cell siROS in the low blast group, as reflected in the high robust CV in these patients. The CD34 antigen is expressed on the surface of various HSCs and progenitors, which exhibit a range of metabolic activities and oxygen availability in their corresponding bone marrow niches. For example, the ROS level of primitive HSCs is lower than in other HSCs [11]. Therefore, when viewed as a single population in the bone marrow of low blast patients, CD34+ cells displayed a wider siROS distribution than the corresponding population in high blast patients, reflecting the presence of a mixture of cell types. We speculate that during the course of clonal evolution to a more aggressive form of MDS, this natural heterogeneity is lost as the CD34+ population becomes homogeneous. Interestingly, the only low blast count patient (patient number 23) whose disease progressed to AML had the narrowest robust CV among the group – plausibly indicative of advanced MDS clonal evolution even though other diagnostic indicators suggested low-grade disease.
Improved placental vascular repair in a rat preeclampsia model by implantation of endothelial progenitor cells treated with platelet microparticles
Published in Hypertension in Pregnancy, 2020
Zhenya Fang, Anna Li, Yaqiong Sun, Xietong Wang, Meihua Zhang
On gd 19, placental tissue sections were fixed with 4% formaldehyde for CD34 and CD133 immunostaining. Other portions of the placenta were prepared as frozen sections for tracking the EPCs. Vessel counts were performed by using the method reported by Weidner et al. Briefly, the area with the highest vascular density was found by light microscopy scanning with low magnification (40–100 times), and then the number of positive for CD34 vessels in the field of vision was counted under the high magnification (200–400 times). Any endothelial cell or endothelial cell cluster positive for CD34 antigen was considered to be a single, countable microvessel. Results were expressed as the highest number of microvessels identified within any single 200x field. Five fields were randomly selected (19).
Survival genes expression analysis following ionizing radiation to LiCl treated KG1a cells
Published in International Journal of Radiation Biology, 2020
Yogesh Kumar Verma, Ajay Kumar Singh, Gangenahalli Ugraiah Gurudutta
LiCl is a well-known drug used for the treatment of bipolar disorders. We undertook this study to understand its role in radiation signaling and radiation protection. We used KG1a cells (human hematopoietic progenitor cell line) in this study as a surrogate for hematopoietic stem cells, since these cells highly express CD34 antigen, a marker for stem cells (Francis et al. 1998). Preceding microarray analysis, the survival and clonogenicity of irradiated KG1a cells were measured. Expectedly LiCl provided protection from radiation in both suspension (KG1a) as well as adherent cell line (NIH3T3). It has been shown earlier that primary tumor cell lines and normal cells survive significantly better after irradiation when adhered to ECM (Sandfort et al. 2007). Contact to ECM proteins increases the amount of cells accumulated in G1-G2 phase upon irradiation, this provides more time for DNA damage repair for the survival of cells as compared to cells lacking ECM contact. This phenomenon is known as Cell Adhesion Mediated Radioresistance (CAM-RR). In order to check the effect of LiCl on CAM-RR, NIH3T3 cells were used. Since LiCl improved clonogenicity and viability of adherent NIH3T cells, it is expected to play a role in CAM-RR.