Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Proliferation and differentiation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

Regulation of hemopoietic cell differentiation and proliferation.

Differentiation and proliferation of almost all hemopoietic cell lines can now be studied in vitro. Cloning techniques and suspension cultures allow the study of proliferation of the multipotential hemopoietic progenitor cell and the committed progenitors for granulocytes, macrophages, eosinophils, megakaryocytes, and erythrocytes. The proliferation of each of the committed progenitor cells is controlled by specific glycoproteins and two of these have recently been purified: granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin. The rate of proliferation of the GM-progenitor cells and their pattern of differentiation depends on the concentration of the hormone. At low concentrations of GM-CSF (10(-11) M) fewer progenitor cells are stimulated and macrophage colonies rather than granulocyte colonies develop. The change in the direction of granulocyte-macrophage differentiation appears to be related to a) the concentration of GM- CSF and b) the different sensitivity of a subpopulation of monocyte colony-forming cells which are responsive to GM-CSF even at low concentrations of the regulator. Analysis of the rate of RNA synthesis by bone marrow cells has shown that GM-CSF stimulates the mature nondividing end cells of differentiation (ie, polymorphs) as well as the progenitor cells. Although GM-CSF and erythropoietin have been radiolabeled, binding studies have been hampered by the loss of biologic activity during the labeling procedure and the heterogeneity of the target cells to which the regulators bind. Surface proteins and receptors for erythrocytes have been well characterized but the relationships between these proteins and the cell surface proteins of nucleated blood cells is not well understood. It appears that some proteins are lost from the cell surface during the development of granulocytes, which are retained on the surface of the B lymphocyte. Other proteins such as chemotactic receptors and complement receptors only appear on the mature cells. External radiolabeling of the granulocyte surface using iodogen yielded a simple profile of 125I-labeled proteins when analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis.

Cell Differentiation↗
PubMed1977

[Prospects for use of the anterior chamber of the eye for studying proliferation, differentiation and hybridization of tumor cells].

The anterior chamber of mammalian eye (ACE) is one of the places of organism privileged immunologically that permits to use it for transplantations of allogenic tissues. Besides, the medium filling the chamber, provides an excellent growth of transplants there, whereas the transparent cornea allows to control the growth. The analysis of results obtained with this method shows its acceptibility both for heterotransplantations of tumors including human tumors, and for homotransplantations with the aim to study the progression of tumors and the selection of constant tumor lines. The ACE is easily applicable for studying morphogenetic potentialities of tumor cells, as well as their ability to differentiation and normalization, because its medium has the quality of "differentiating" for many tissues. Cytological heterogeneity, revealed during tumor transplantations, allows to study the spectrum of cytological variability and transgression of tumor characters at different stages of their progression. The ACE can be used for estimation of tumor formation ability of tumor cells by determining TD50 (tumor dosis 50) which is important for estimation of different kinds of damage (X-rays, chemotherapy etc.). According to authors' point of view, it is very perspective to use the anterior chamber of eye for elaboration of effective methods of hybridization tumor cells with normal ones.

Animals↗
PubMed1977

In vitro immune response of human peripheral lymphocytes. I. The mechanism(s) involved in T cell helper functions in the pokeweed mitogen-induced differentiation and proliferation of B cells.

Human peripheral lymphocytes (PBL) upon stimulation with PWM proliferate and differentiate to IgM- and IgG-producing cells. The PWM-induced Ig production in B cells was dependent on T cells, and cell-free supernatant (CFS) obtained from PWM-stimulated PBL or T cell-rich fraction replaced T cell helper functions. The active substance(s) in CFS were most likely derived from T cells. The kinetic studies showed that the proliferation of B cells took place in advance of the final differentiation to Ig-producing cells and that T cells or T cell product(s) had to exist at the initiation of cultures in order to give the maximum helper effect. However, the final differentiation of B cells to Ig-producing cells was not dependent on T cells. The helper effect of T cells or T cell product(s) on PWM-induced proliferation and differentiation of B cells was exerted across the MHC barrier. This may make it possible to apply this experimental system to the assessment of quantitative and/or qualitative changes in human helper T cells in several immunologic diseases.

Antibody-Producing Cells↗
PubMed1978

Effects of allogeneic stimulations on the proliferation and differentiation of the hemopoietic stem cell.

The effects of allogeneic stimulatins on the hemopoietic system were investigated. Spleen cells of mice activated in vivo with alloantigens were able to produce highly active colony-stimulating factor in the culture medium without any stimulation. But spleen cells of these mice could not release colony-stimulating factor after treatment in vitro with anti-theta serum and complement. The number of granulopoietic progenitor cells (colony-forming unit-culture) in both bone marrow and spleen cells of mice treated with such procedures was significantly greater than that of the control, and the number of pluripotent stem cells (colony-forming unit-spleen) of these mice was markedly increased compared with that of the control, especially in spleen cells. These experiments suggest that T lymphocytes activated in vivo with alloantigens may release active substances in the differentiation and proliferation of hemopoietic stem cells.

Animals↗
PubMed1975

Effects of aging on the differentiation and proliferation potentials of cells of the immune system.

An attempt has been made here to show that the immune system can begin to decline in function shortly after an individual reaches maturity. The decline is due in part to changes in the environment of the cells but primarily to changes in the precursor cells of the system. This is reflected in their inability to proliferate and possibly differentiate efficiently. These findings show that the immune system can serve as an excellent model to study how aging can perturb the process of cells undergoing proliferation and differentiation.

Aging↗
PubMed2026

Transcriptomic insights into temperature regulation of proliferation and differentiation in skeletal muscle cells of Nibea albiflora.

Myogenesis involves sequential stages of muscle satellite cell activation, myoblast proliferation, differentiation, and fusion into multinucleated myotubes. Teleost muscle exhibits indeterminate growth and is highly sensitive to environmental temperature, yet the underlying mechanisms by which temperature regulate proliferation and differentiation remain poorly understood. In this study, we established a primary skeletal muscle cell culture from the yellow drum (Nibea albiflora), an economically important marine fish, and integrated morphological observations with comparative transcriptomics analysis to characterize cellular and molecular responses at 28 °C and 20 °C during both proliferation and differentiation stages. Phenotypic analysis revealed that 28 °C significantly enhanced both myoblast proliferation and myogenic differentiation ability compared with 20 °C. Transcriptomic profiling revealed that at 28 °C, differentiation upregulated extracellular matrix(ECM) organization, calcium signaling, and sarcomere assembly, while proliferation enhanced focal adhesion, growth factor signaling, and lipid metabolism. At 20 °C, differentiation was characterized by glutathione metabolism, and ferroptosis, while proliferation involved cytokine-cytokine receptor interaction and negative regulation of signal transduction. Core myogenic regulatory factors (MRFs), particularly myogenin, were strongly upregulated at 28 °C during the differentiation stage, serving as an internal control. Based on these findings, we propose a testable model that elevated temperature coordinates Ca2+-dependent MRF activation with ECM-integrin signaling to drive sarcomere assembly and muscle growth. Key differentially expressed genes (DEGs) regulating myogenesis in N. albiflora were also identified. This study provides a mechanistic framework for temperature adaptation in teleost skeletal muscle and identifies candidate genes for functional validation and marker-assisted selection, as well as a rationale for temperature management strategies to improve aquaculture yield of N. albiflora.

Animals↗
PubMed1979

[Cell proliferation and migration in the roof of the mesencephalon (tectum) in Xenopus laevis tadpoles and adult frogs normally and in brain injury. II. Cell proliferation and differentiation of the tectum in frogs].

The proliferation and directions of cell differentiation in tectum opticum were studied in the young frogs under the conditions of normal development and upon brain trauma by means of 3H-thymidine autoradiography. The same types of cells were shown to be able of proliferation in both the cases: cells of the ventricle zone and glioblasts (gliocytes) in all other tectum layers. A study of directions of the tectum proliferating cells' differentiation in the frogs has shown that the proliferating cells differentiate mainly in the ependyme tanicytes in the ventricle layer 1 and gliocytes in the other tectum layers. The trauma did not change the direction of proliferating cells' differentiation towards the formation of neurons. The complete regeneration is observed in the tectum layer 1 only.

Animals↗
PubMed1975

Cyclic AMP, cyclic GMP, and glucocorticoids as potential metabolic regulators of epidermal proliferation and differentiation.

The two cyclic nucleotides, cyclic AMP and cyclic GMP, appear to be central to the metabolic regulation of cell proliferation and differentiation in various cells. Moreover, in many systems glucocorticoids appear to act in concert with or parallel to cyclic AMP. The available evidence suggests that these three molecular species--cyclic AMP, cyclic GMP, and glucocorticoids--may be essential to the normal regulation of epidermal proliferation and differentiation. In 1970, we suggested that perturbed epidermal homeostasis, exemplified by psoriasis, might be associated with low cellular levels of cyclic AMP and, in 1972, with high levels of cyclic GMP as well. Subsequent measurements of these two cyclic nucleotides in our laboratory showed a probable reduction in the cyclic AMP/cyclic GMP ratio in lesional psoriatic tissue. This led to the hypothesis that the cardinal features of psoriatic epidermis--glycogen accumulation, excessive proliferation, and reduced cell specialization--are the results of this reduced ratio. A corollary of this hypothesis was that a psoriatic lesion could not begin or exist without this altered cyclic nucleotide ratio. Recently, four different agents--lithium, a beta adrenergic blocking agent, antimalarials, and iodide--have been found to exacerbate psoriasis and to reduce the formation of cyclic AMP in various tissues. Consequently we believe that cyclic nucleotides are of central importance in the pathogenesis of the epidermal component of psoriasis.

Animals↗
PubMed1977

Slide chamber culture system for the in vitro study of humoral regulation of granulocyte and monocyte-macrophage proliferation and differentiation.

A liquid culture system employing slide chambers was developed to facilitate the study of proliferation and differentiation of mouse neutrophilic granulocytes and cells of the monocyte-macrophage series. Cultures were initiated with 1-2.5 X 10(4) light density marrow cells which had been fractionated on Ficoll-Hypaque. In the presence of colony-stimulating activity (CSAHU), two types of clusters were observed. One was tight, spheroidal, and composed of neutrophilic granulocytes, while the other was a loose grouping of flattened cells of the monocyte-macrophage series. The slide chamber culture is adaptable to microscopic assay techniques (e.g., cluster size, autoradiography, immunofluorescence) as well as quantitative biochemical methods (e.g., rate of 3H-thymidine incorporation, DNA quantitation). We have demonstrated both a shortening of the generation time of granulocytes in tight clusters and increasing rates of 3H-thymidine incorporation into DNA, with a corresponding increase in total culture DNA as a function of CSAHU concentration. Granulocytic differentiation in the tight spheroidal clusters has been demonstrated by histochemical stains and immunofluorescence of an antibody to a marker protein specific for the secondary granule of the neutrophil (lactoferrin).

Animals↗
PubMed1978

Some factors influencing the proliferation and differentiation of myelin-forming cells.

Fundamental questions arising from study of the multiple sclerosis lesion are: (1) why the myelin-forming oligodendrocyte is adversely affected; and (2) what factors might induce the proliferation and differentiation of replacement oligodendrocytes. This paper discusses factors that influence the number and differentiative capacity of myelin-forming cells both in the central nervous system (CNS) and the peripheral nervous system (PNS). New experiments utilizing cultures of fetal rat sensory and autonomic ganglia are also herein reported. It has been found that in cultures free of fibroblasts, normal Schwann cell proliferation and ensheathment of axons require contact with a collagen substrate and may be facilitated by a medium containing chick embryo extract. This demonstration of a connective tissue requirement for normal Schwann cell function raises the question of whether additional factors are necessary for normal oligodendrocyte activity.

Animals↗
PubMed2025

Mechanism of histone demethylase KDM5A in osteoporotic fracture healing through epigenetic regulation of the miR-495/SKP2/Runx2 axis.

BACKGROUND: Osteoporosis represents a salient metabolic bone disorder. Histone demethylase plays a vital role in bone development and homeostasis. This study explored the mechanism of histone demethylase KDM5A affecting osteoporotic fracture healing via the miR-495/SKP2/Runx2 axis. METHODS: The murine model of osteoporotic fracture was established. The bone mineral density, maximum elastic stress, and maximum load were tested. The relative trabecular bone volume, bone trabecular thickness, and trabecular number at the proximal end of tibia were detected. The histopathological changes of femur tissues and bone microstructure were observed. Expressions of KDM5A and osteogenic factors were detected. The cell proliferation, alkaline phosphatase activity, and calcified nodules were measured. The binding relationships between KDM5A and miR-495 promoter, and miR-495 and SKP2 were verified. The interaction between SKP2 and Runx2 was detected. The ubiquitination level of Runx2 and the stability of Runx2 protein were detected. RESULTS: KDM5A was highly expressed in the murine model of osteoporotic fracture. Interference of KDM5A expression facilitated fracture healing in osteoporotic mice. KDM5A downregulated miR-495 expression by promoting the H3K4me3 methylation of the miR-495 promoter. Inhibition of miR-495 reversed the effect of KDM5A silencing on osteoblast proliferation, differentiation, and mineralization. miR-495 facilitated osteoblast proliferation, differentiation, and mineralization by targeting SKP2. SKP2 suppressed Runx2 expression through ubiquitination degradation. Inhibition of Runx2 reversed the promoting effect of SKP2 silencing on osteogenic differentiation. CONCLUSION: KDM5A attenuated the inhibition of miR-495 on SKP2 and promoted the ubiquitination degradation of Runx2 protein by SKP2, thereby repressing osteoblast differentiation and retarding osteoporotic fracture healing.

Animals↗
PubMed1979

[Correlation between the processes of proliferation and differentiation in the histogenesis of somatic muscle tissue in birds].

The development of muscular tissue fibers has been studied in 8--19-day-old chick embryos by methods of electron microscopy, autoradiography and cytophotometry. Differentiated myogenic elements are derived from promyoblasts which devide during myogenesis at slightly changing parameters of the mytotic cycle. Promyoblasts fuse with each other or with symplasts or else can develop into myoblasts containing myofilaments in their cytoplasm. At later stages of myogenesis, some promyoblasts pass into "rest" condition with characteristic changes in the structure of nucleus, cytoplasm and muscular cells. These cells are situated between the basal and cytoplasmic membranes and identified as cell-satellites (myosatellites). They represent an important subpopulation of the muscular system, which preserve a certain ability to perceive stimuli to proliferation and differentiation, forming the cambial system of the skeletal-muscular tissue.

Animals↗
PubMed1979

Long-term cultivation of human mammary carcionoma: proliferation and differential biochemical properties of the cultured cells.

Human mammary carcinoma cell cultures proliferated from primary explants in Eagle's essential medium (MEM) supplemented with insulin, fetal calf serum (FCS) and/or human alpha-a1-antitrypsin. Human mammary carcinoma cells differed from normal mammary epithelial cells by the following catalytic activities: a. Thymidine uptake into the carcinoma cells was 6 to 10 fold greater, whereas thymidine conversion to CO2 was half to one fifth that of normal cells. b. The nucleolytic activity patterns of the mammary carcinoma cells preferred polycytydylic acid and double helical polynucleotides, whereas those of the normal mammary cells preferred polyuridylic acid and had no effect on double helical polynucleotides. c. The polymerase activity most evident in mammary carcinoma cells is a hybrid-dependent DNA polymerase which is guided by the ribo-strand of the template poly (rA) . poly(dT). In contrast the all-ribo template poly (rA) . poly(rU) showed little activity. d. There was slight or statistically non-significant difference between the amino acid composition of material cleaved from mammary carcinoma cells prepared from tumor tissues and from cells cultivated 10 months in vitro. e. There was no difference between the molar proportions of the carbohydrate components of the cell membrane from fresh tumor tissue and long term in vitro cultivated cells. f. The granules from long term in vitro cultured mammary carcinoma cells contained high collagenolytic, caseinolytic, fibrinolytic and esterolytic activities.

Amino Acids↗
PubMed1975

Trophic influences of sympathetic nerves and cyclic AMP on differentiation and proliferation of isolated smooth muscle cells in culture.

Smooth muscle cells of the newborn guinea-pig vas deferens dispersed into single cells and grown in culture maintain their differentiation for approximately 5 days before undergoing dedifferentiation and mitosis. The presence of sympathetic nerve fibres in contact with the isolated cells delays this process by 3-7 days (Chamley et al., 1974). A similar delay in dedifferentiation of vas deferens smooth muscle cells in tissue culture in the presence of sympathetic ganglion extract is described in the present report, demonstrating that the trophic effect is elicited by a chemical substance. This effect is mimicked by the presence of either a confluent layer of RKA epithelial cells, dibutyryl cyclic AMP or theophylline. A similar, but considerably weaker, effect is also obtained with spinal cord and liver extracts and noradrenaline. Acetylcholine does not show an effect. It is suggested that a trophic substance (probably not noradrenaline) from sympathetic neurons activates the adenyl cyclase system of smooth muscle cells to increase the intracellular level of cyclic AMP which in turn promotes and maintains the differentiation of the cultured smooth muscle cells.

Acetylcholine↗
PubMed1978

Effects of theophylline, epidermal chalone and x-irradiation on proliferation and differentiation of human keratinocytes in vitro.

Outgrowth cultures of normal human epidermis were used to study a possible relationship between growth inhibition and differentiated function. The effects of theophylline, epidermal chalone and x-irradiation on mitoses and the characteristic production of epidermal keratohyaline granules (KG) were examined at various intervals after the treatment. Theophylline (an inhibitor of cyclic nucleotide phosphodiesterase) or epidermal chalone inhibited mitoses and enhanced KG production. X-irradiation inhibited mitoses but had no effect on KG formation. These results indicate that inhibition of proliferation per se is not sufficient to enhance keratinization of human epidermal cells.

Cell Differentiation↗