Home About us Contact
|
Home About us Contact | ||
|
|
||
Heterogeneous Cell Populations (heterogeneous + cell_population)
Selected AbstractsHeterogeneous cell populations in tumorsBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2008Article first published online: 24 SEP 200 No abstract is available for this article. [source] Identification of marker genes distinguishing human periodontal ligament cells from human mesenchymal stem cells and human gingival fibroblastsJOURNAL OF PERIODONTAL RESEARCH, Issue 3 2007T. Fujita Background and Objective:, Molecular gene markers, which can distinguish human bone marrow mesenchymal stem cells from human fibroblasts, have recently been reported. Messenger RNA levels of tissue factor pathway inhibitor-2, major histocompatibility complex-DR-,, major histocompatibility complex-DR-,, and neuroserpin are higher in human bone marrow mesenchymal stem cells than in human fibroblasts. However, human bone marrow mesenchymal stem cells express less apolipoprotein D mRNA than human fibroblasts. Periodontal ligament cells are a heterogeneous cell population including fibroblasts, mesenchymal stem cells, and progenitor cells of osteoblasts or cementoblasts. The use of molecular markers that distinguish human bone marrow mesenchymal stem cells from human fibroblasts may provide insight into the characteristics of human periodontal ligament cells. In this study, we compared the molecular markers of human periodontal ligament cells with those of human bone marrow mesenchymal stem cells and human gingival fibroblasts. Material and Methods:, The mRNA expression of the molecular gene markers was analyzed using real-time polymerase chain reaction. Statistical differences were determined with the two-sided Mann,Whitney U -test. Results:, Messenger RNA levels of major histocompatibility complex-DR-, and major histocompatibility complex-DR-, were lower and higher, respectively, in human periodontal ligament cells than in human bone marrow mesenchymal stem cells or human gingival fibroblasts. Human periodontal ligament cells showed the lowest apolipoprotein D mRNA levels among the three types of cells. Conclusion:, Human periodontal ligament cells may be distinguished from human bone marrow mesenchymal stem cells and human gingival fibroblasts by the genes for apolipoprotein D, major histocompatibility complex-DR-,, and major histocompatibility complex-DR-,. [source] Characterization of benign and malignant prostate epithelial Hoechst 33342 side populationsTHE PROSTATE, Issue 13 2007Mick D. Brown Abstract Background The prostate epithelial stem cell has been proposed as the primary origin of neoplastic change in prostate cancer. However, the isolation and characterization of unexpanded prostate epithelial stem cells have proven problematic. Methods A prostate epithelial side population (SP) has been isolated utilizing a modified Hoechst 33342 dye efflux assay from both benign and malignant prostate tissue. CD45,ve, integrin ,2+ve Hoechst 33342 SP and NSP cells were isolated by FACS, immunophenotyped and functionally characterized in 3D culture. Results FACS analysis revealed a verapamil sensitive SP accounting for 0.93,±,0.12% and 0.57,±,0.11% of the total epithelial population from both benign and malignant prostates. The benign SP phenotype revealed a heterogeneous cell population consisting predominantly of small basal cells containing minimal cytoplasm. Conversely, the malignant SP was of undetermined acinar origin and with a complete loss of expression of the CDK2 inhibitor p21WAF1/Cip1. In vitro androgen-enhanced 3D culture of the benign and malignant SP cells led to the production of spheroids which had acinus like morphology and expressed primitive and basal cell markers. Incorporation of the CD133 marker isolated a further SP sub-fraction accounting for 0.037,±,0.01% of epithelial cells. Conclusions Our observations are consistent with the Hoechst 33342 dye efflux assay isolating a stem cell enriched population which can be further sub-fractionated by CD133 selection. Moreover, the loss of the CDK inhibitor in malignancy is consistent with the hypothesis that neoplastic change originates in the stem cell compartment. Prostate 67: 1384,1396, 2007. © 2007 Wiley-Liss, Inc. [source] Group IIA phospholipase A2 is coexpressed with SNAP-25 in mature taste receptor cells of rat circumvallate papillaeTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2006Hideaki Oike Abstract The taste buds are composed of heterogeneous cell populations with diverse properties and at different stages of maturity. It is important to define the relationships between cell properties and cell maturity to understand the molecular events involved in intracellular taste signaling. In the present study, in situ hybridization analysis indicated that group IIA phospholipase A2 (PLA2 -IIA) is expressed in a subset of taste bud cells. Immunohistochemical studies showed that PLA2 -IIA was expressed in a subset of cells expressing phospholipase C,2, a molecule essential for taste signaling in taste receptor cells, and also that some PLA2 -IIA-positive cells expressed gustducin (Ggust), a bitter-taste-signaling molecule. Although PLA2 -IIA and Ggust were expressed at similar frequencies in taste buds, bromodeoxyuridine (BrdU) chase experiments indicated that the expression of Ggust began 2 days after BrdU injection, whereas the expression of PLA2 -IIA commenced after 4 days. In addition, PLA2 -IIA was coexpressed with SNAP-25, a synaptosomal-associated protein. These results indicated that PLA2 -IIA is expressed in mature taste receptor cells that possess exocytotic machinery. J. Comp. Neurol. 494:876,886, 2006. © 2005 Wiley-Liss, Inc. [source] A novel assay based on fluorescence microscopy and image processing for determining phenotypic distributions of rod-shaped bacteriaBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2009Konstantinos Spetsieris Abstract Cell population balance (CPB) models can account for the phenotypic heterogeneity that characterizes isogenic cell populations. To utilize the predictive power of these models, however, we must determine the single-cell reaction and division rates as well as the partition probability density function of the cell population. These functions can be obtained through the Collins,Richmond inverse CPB modeling methodology, if we know the phenotypic distributions of (a) the overall cell population, (b) the dividing cell subpopulation, and (c) the newborn cell subpopulation. This study presents the development of a novel assay that combines fluorescence microscopy and image processing to determine these distributions. The method is generally applicable to rod-shaped cells dividing through the formation of a characteristic constriction. Morphological criteria were developed for the automatic identification of dividing cells and validated through direct comparison with manually obtained measurements. The newborn cell subpopulation was obtained from the corresponding dividing cell subpopulation by collecting information from the two compartments separated by the constriction. The method was applied to E. coli cells carrying the genetic toggle network with a green fluorescent marker. Our measurements for the overall cell population were in excellent agreement with the distributions obtained via flow cytometry. The new assay constitutes a powerful tool that can be used in conjunction with inverse CPB modeling to rigorously quantify single-cell behavior from data collected from highly heterogeneous cell populations. Biotechnol. Bioeng. 2009;102: 598,615. © 2008 Wiley Periodicals, Inc. [source] Resolving and classifying haematopoietic bone-marrow cell populations by multi-dimensional analysis of flow-cytometry dataBRITISH JOURNAL OF HAEMATOLOGY, Issue 3 2005Eli Zamir Summary The study of normal or malignant haematopoiesis requires the analysis of heterogeneous cell populations using multiple morphological and molecular criteria. Flow cytometry has the capacity to acquire multi-parameter information of large haematopoietic cell populations, utilizing various combinations of >200 molecular markers (clusters of differentiation, CD). However, current flow cytometry analyses are based on serial gating of two-parametric scatter plots , a process that is inherently incapable to discriminate all subgroups of cells in the data. Here we studied the cellular diversity of normal bone marrows (BM) using multi-dimensional cluster analysis of six-parametric flow cytometry data (four CD, forward scatter and side scatter), focusing mainly on the myeloid lineage. Twenty-three subclasses of cells were resolved, many of them inseparable even when examined in all possible two-parametric scatter plots. The multi-dimensional analysis could distinguish the haematopoietic progenitors according to International Society of Haematotherapy and Graft Engineering criteria from other types of immature cells. Based on the defined clusters, we designed a classifier that assigns BM cells in samples to subclasses based on robust six-dimensional position and extended shape. The analysis presented here can manage successfully both the increasing numbers of haematopoietic cellular markers and sample heterogeneity. This should enhance the ability to study normal haematopoiesis, and to identify and monitor haematopoietic disorders. [source] | |||||||||||||