Proliferative Cell Populations in Surface Epithelia: Biological Models for Cell Replacement

1980 ◽  
pp. 23-35 ◽  
Author(s):  
C. S. Potten
Keyword(s):  
Cell Populations ◽  
Biological Models ◽  
Cell Replacement ◽  
Proliferative Cell

scholarly journals Derivation of keratinocytes from chicken embryonic stem cells: Establishment and characterization of differentiated proliferative cell populations

2015 ◽  
Vol 14 (2) ◽  
pp. 224-237 ◽  
Author(s):  
Mathilde Couteaudier ◽  
Laëtitia Trapp-Fragnet ◽  
Nicolas Auger ◽  
Katia Courvoisier ◽  
Bertrand Pain ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Cell Populations ◽  
Chicken Embryonic Stem Cells ◽  
Proliferative Cell

Diversity of cell lengths in intercalary meristem regions of grasses: location of the proliferative cell population

2004 ◽  
Vol 82 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Lance S Evans ◽  
Rocio K Perez
Keyword(s):  
Zea Mays L ◽  
Age Distribution ◽  
Length Distribution ◽  
Triticum Aestivum L ◽  
Grass Species ◽  
Cell Populations ◽  
Cell Age ◽  
Parenchyma Cells ◽  
Intercalary Meristem ◽  
Proliferative Cell

Intercalary meristems are responsible for the production of the majority of cells in stems. The overall objective of the present study was to determine (i) the boundaries of the proliferative parenchyma cells in the intercalary meristems and (ii) the proliferative capacity of cells in the intercalary meristems in stems of a species of Bambusa Schreb. (bamboo), Phragmites australis (Cav.) Trin. ex Steud., Triticum aestivum L., and Zea mays L. Data show that lengths of parenchyma cells within proliferative portions of intercalary meristems were not the same for all intercalary meristems of a species. Lengths of elongated parenchyma cells in internodes were relatively similar among internodes of a species, but lengths of elongated parenchyma cells in internodes were not similar among the four grass species tested. For example, cell lengths of elongated parenchyma cells in internodes of P. australis ranged from 14.8 to 23.0 µm, very different from lengths of elongated cells in Bambusa sp. (69.1–75.4 µm). The number of proliferative cells in most files of intercalary meristems of Bambusa was less than 15. For many of the intercalary meristems of P. australis, the intercalary meristem consisted of 10–25 cells in each file. Fourth intercalary meristems of T. aestivum and Z. mays consisted of 20 and 25 cells in files, respectively. Data showed that none of the cell populations of the intercalary meristems of four species exhibited an exponential cell length distribution. In general, less than half of the 10 groups of cells had percentages of cells that resembled an exponential cell-age distribution. These data lead to the conclusion that not all parenchyma cells of intercalary meristems are rapidly proliferating. Also, potentially prolifera tive cells (short cells) of the intercalary meristems may not be localized into a specific zone but are more scattered throughout the nodal region.Key words: intercalary meristems, proliferative cell populations, Gramineae, cell lengths.

Neural Stem Cells: From Cell Biology to Cell Replacement

2000 ◽  
Vol 9 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Richard J. E. Armstrong ◽  
Clive N. Svendsen
Keyword(s):  
Stem Cells ◽  
Nervous System ◽  
Replacement Therapy ◽  
Cell Biology ◽  
Ex Vivo ◽  
Cell Populations ◽  
Cell Replacement Therapy ◽  
Diverse Range ◽  
Cell Replacement ◽  
Functional Benefit

A large number of crippling neurological conditions result from the loss of certain cell populations from the nervous system through disease or injury, and these cells are not intrinsically replaced. Mounting evidence now suggests that replacement of depleted cell populations by transplantation may be of functional benefit in many such diseases. A diverse range of cell populations is vulnerable, and the loss of specific populations results in circumscribed deficits in different conditions. This diversity presents a considerable challenge if cell replacement therapy is to become widely applicable in the clinical domain, because each condition has specific requirements for the phenotype, developmental stage, and number of cells required. An ideal cell for universal application in cell replacement therapy would possess several key properties: it would be highly proliferative, allowing the ex vivo production of large numbers of cells from minimal donor material; it would also remain immature and phenotypically plastic such that it could differentiate into appropriate neural and glial cell types on, or prior to, transplantation. Critically, both proliferation and differentiation would be controllable. This review considers some of the evidence that stem cells exist in the central nervous system and that they may possess characteristics that make them ideal for broad application in cell replacement therapy.

scholarly journals Developmental and cellular age direct conversion of CD4+ T cells into RORγ+ or Helios+ colon Treg cells

2019 ◽  
Vol 217 (1) ◽  
Author(s):  
Alvin Pratama ◽  
Alexandra Schnell ◽  
Diane Mathis ◽  
Christophe Benoist
Keyword(s):  
T Cells ◽  
Treg Cell ◽  
Direct Conversion ◽  
Treg Cells ◽  
Physiological Adaptation ◽  
Cell Populations ◽  
Rna Seq ◽  
Cell Replacement ◽  
Replacement System ◽  
The Individual

RORγ+ and Helios+ Treg cells in the colon are phenotypically and functionally distinct, but their origins and relationships are poorly understood. In monocolonized and normal mice, single-cell RNA-seq revealed sharing of TCR clonotypes between these Treg cell populations, potentially denoting a common progenitor. In a polyclonal Treg cell replacement system, naive conventional CD4+ (Tconv) cells, but not pre-existing tTregs, could differentiate into RORγ+ pTregs upon interaction with gut microbiota. A smaller proportion of Tconv cells converted into Helios+ pTreg cells, but these dominated when the Tconv cells originated from preweaning mice. T cells from infant mice were predominantly immature, insensitive to RORγ-inducing bacterial cues and to IL6, and showed evidence of higher TCR-transmitted signals, which are also characteristics of recent thymic emigrants (RTEs). Correspondingly, transfer of adult RTEs or Nur77high Tconv cells mainly yielded Helios+ pTreg cells, recapitulating the infant/adult difference. Thus, CD4+ Tconv cells can differentiate into both RORγ+ and Helios+ pTreg cells, providing a physiological adaptation of colonic Treg cells as a function of the age of the cell or of the individual.

scholarly journals A General Mechano-Pharmaco-Biological Model for Bone Remodeling Including Cortisol Variation

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1401
Author(s):  
Rabeb Ben Kahla ◽  
Abdelwahed Barkaoui ◽  
Moez Chafra ◽  
João Manuel R. S. Tavares
Keyword(s):  
Mathematical Model ◽  
Bone Remodeling ◽  
Cell Populations ◽  
Biological Models ◽  
Mass Variation ◽  
Proposed Model ◽  
The Future ◽  
Mechanical Models ◽  
General Mathematical Model ◽  
Current Article

The process of bone remodeling requires a strict coordination of bone resorption and formation in time and space in order to maintain consistent bone quality and quantity. Bone-resorbing osteoclasts and bone-forming osteoblasts are the two major players in the remodeling process. Their coordination is achieved by generating the appropriate number of osteoblasts since osteoblastic-lineage cells govern the bone mass variation and regulate a corresponding number of osteoclasts. Furthermore, diverse hormones, cytokines and growth factors that strongly link osteoblasts to osteoclasts coordinated these two cell populations. The understanding of this complex remodeling process and predicting its evolution is crucial to manage bone strength under physiologic and pathologic conditions. Several mathematical models have been suggested to clarify this remodeling process, from the earliest purely phenomenological to the latest biomechanical and mechanobiological models. In this current article, a general mathematical model is proposed to fill the gaps identified in former bone remodeling models. The proposed model is the result of combining existing bone remodeling models to present an updated model, which also incorporates several important parameters affecting bone remodeling under various physiologic and pathologic conditions. Furthermore, the proposed model can be extended to include additional parameters in the future. These parameters are divided into four groups according to their origin, whether endogenous or exogenous, and the cell population they affect, whether osteoclasts or osteoblasts. The model also enables easy coupling of biological models to pharmacological and/or mechanical models in the future.

Electron microscopy of endocardial cell populations

1978 ◽  
Vol 36 (2) ◽  
pp. 486-487
Author(s):  
T. G. Sarphie ◽  
C. R. Comer ◽  
D. J. Allen
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Cellular Transformation ◽  
Cell Populations ◽  
Cell Surfaces ◽  
Kb Cells ◽  
Dna Viruses ◽  
Cell Cycles ◽  
Ultrastructural Studies ◽  
Endocardial Cell

Previous ultrastructural studies have characterized surface morphology during norma cell cycles in an attempt to associate specific changes with specific metabolic processes occurring within the cell. It is now known that during the synthetic ("S") stage of the cycle, when DNA and other nuclear components are synthesized, a cel undergoes a doubling in volume that is accompanied by an increase in surface area whereby its plasma membrane is elaborated into a variety of processes originally referred to as microvilli. In addition, changes in the normal distribution of glycoproteins and polysaccharides derived from cell surfaces have been reported as depreciating after cellular transformation by RNA or DNA viruses and have been associated with the state of growth, irregardless of the rate of proliferation. More specifically, examination of the surface carbohydrate content of synchronous KB cells were shown to be markedly reduced as the cell population approached division Comparison of hamster kidney fibroblasts inhibited by vinblastin sulfate while in metaphase with those not in metaphase demonstrated an appreciable decrease in surface carbohydrate in the former.

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