Search results for "Spheroid"
showing 10 items of 133 documents
Dynamic regulation of the cancer stem cell compartment by Cripto-1 in colorectal cancer.
2015
Stemness was recently depicted as a dynamic condition in normal and tumor cells. We found that the embryonic protein Cripto-1 (CR1) was expressed by normal stem cells at the bottom of colonic crypts and by cancer stem cells (CSCs) in colorectal tumor tissues. CR1-positive populations isolated from patient-derived tumor spheroids exhibited increased clonogenic capacity and expression of stem-cell-related genes. CR1 expression in tumor spheroids was variable over time, being subject to a complex regulation of the intracellular, surface and secreted protein, which was related to changes of the clonogenic capacity at the population level. CR1 silencing induced CSC growth arrest in vitro with a …
Types of Motion in the Oblate Planet Problem
1985
We consider a mass point in the gravitational field of an oblate planet and in a meridianal plane. The Hamiltonian of the problem is: $$ \frac{1}{2}\left( {p_r^2 + \frac{{p_{\theta }^2}}{{{r^2}}}} \right) - \frac{1}{r} - \frac{\varepsilon }{{{r^3}}}\left( {1 - 3{{\sin }^2}\theta } \right) $$ .
A code to evaluate prolate and oblate spheroidal harmonics
1998
Abstract We present a code to evaluate prolate ( P n m ( x ), Q n m ( x ); n ≥ m , x > 1) and oblate ( P n m ( ix ), Q n m ( ix ); n ≥ m , x > 0) spheroidal harmonics, that is, spherical harmonics ( n and m integers) for real arguments larger than one and for purely imaginary arguments. We start from the known values (in closed form) of P m m and P m +1 m and we apply the forward recurrence relation over n up to a given degree n = N Max . The Wronskian relating P 's and Q 's, together with the evaluation of the continued fraction for Q m+N staggeredMax m / Q m+N staggeredMax -1 m , allows the calculation of Q m+N staggeredMax m and Q m+N staggeredMax -1 m . Backward recurrence is then appli…
Test system for trifunctional antibodies in 3D MCTS culture.
2009
The aim of the present study was to assess the feasibility of a 3D tumor cell culture model, that is, multicellular tumor spheroids (MCTSs) as an adequate model for micrometastases and therefore as a pharmacological model for efficacy testing of trifunctional therapeutic antibodies. Unlike conventional monolayer cultures, spheroids allow researchers to study parameters, such as 3D cell shape, 3D cell arrangement and microenvironment, and penetration efficiency of defense cells that may largely influence the efficacy of antibody treatment in vivo. The authors established a long-term coculture of human MCTSs with peripheral blood mononuclear cells (PBMCs) to test the anticancer effect of the …
Dual roles of Aβ in proliferative processes in an amyloidogenic model of Alzheimer’s disease
2017
Alzheimer’s disease is a major neurodegenerative disorder that leads to severe cognitive deficits in the elderly population. Over the past two decades, multiple studies have focused on elucidating the causative factors underlying memory defects in Alzheimer’s patients. In this regard, new evidence linking Alzheimer’s disease-related pathology and neuronal stem cells suggests that hippocampal neurogenesis impairment is an important factor underlying these cognitive deficits. However, because of conflicting results, the impact of Aβ pathology on neurogenesis/gliogenesis remains unclear. Here, we investigated the effect of Aβ on neuronal and glial proliferation by using an APP/PS1 transgenic m…
A novel model of human implantation: 3D endometrium-like culture system to study attachment of human trophoblast (Jar) cell spheroids.
2011
There is an urgent need to develop optimized experimental models to examine human implantation. These studies aimed to (i) establish a human endometrium-like three-dimensional (3D) culture system, and (ii) examine the attachment of trophoblast-like Jar spher- oids to the culture. In the present work, 3D endometrial cultures were constructed with fibrin-agarose as matrix scaffold, and using epithelial and stromal cells from both human primary cultures and established cell lines. An attachment assay between trophoblast cells and the 3D culture was developed. Epithelial cells (cytokeratin + ) concentrated on top of the matrix forming a monolayer, and stromal cells (vimentin + ) resided within …
Arsenic trioxide alters the differentiation of mouse embryonic stem cell into cardiomyocytes
2015
AbstractChronic arsenic exposure is associated with increased morbidity and mortality for cardiovascular diseases. Arsenic increases myocardial infarction mortality in young adulthood, suggesting that exposure during foetal life correlates with cardiac alterations emerging later. Here, we investigated the mechanisms of arsenic trioxide (ATO) cardiomyocytes disruption during their differentiation from mouse embryonic stem cells. Throughout 15 days of differentiation in the presence of ATO (0.1, 0.5, 1.0 μM) we analysed: the expression of i) marker genes of mesoderm (day 4), myofibrillogenic commitment (day 7) and post-natal-like cardiomyocytes (day 15); ii) sarcomeric proteins and their orga…
Approximation of exit times for one-dimensional linear diffusion processes
2020
International audience; In order to approximate the exit time of a one-dimensional diffusion process, we propose an algorithm based on a random walk. Such an algorithm was already introduced in both the Brownian context and the Ornstein-Uhlenbeck context, that is for particular time-homogeneous diffusion processes. Here the aim is therefore to generalize this efficient numerical approach in order to obtain an approximation of both the exit time and position for a general linear diffusion. The main challenge of such a generalization is to handle with time-inhomogeneous diffusions. The efficiency of the method is described with particular care through theoretical results and numerical example…
Changes in O2 Consumption of Multicellular Spheroids During Development of Necrosis
1985
Multicellular spheroids are spherical aggregates of cells that are supplied by diffusion of oxygen and substrates from the surrounding growth medium (Sutherland and Durand, 1976). Metabolic waste products are removed from the cells in these aggregates by diffusion into the growth medium. Cells within multicellular spheroids may be exposed to environmental conditions similar to those in tissue located between nutritive microvessels. Thus, tumor spheroids make it possible to study the impact of the tumor-specific micromilieu on cellular metabolism, cell cycle state, cellular viability or response to treatment. Factors in the microenvironment of tumor cells which may be relevant in this regard…
An Analysis of the Immunomodulatory Properties of Human Spheroids from Adipose-Derived Stem Cells
2023
Aims Current methods to induce tolerance following allotransplantation or in autoimmunity carry significant morbidity, and research is very active in investigating alternative methods which could minimize toxicity. Spheroids from adipose stem cells (SASCs) are increasingly gaining interest, they hold a great proliferative and differentiating potential. An immunomodulatory effect has not been investigated on SASCs yet. In this study, we analysed the immunomodulatory properties of SASCs and compared them to ADSCs. Main methods Adipose stem cells (SASCs and ADSCs) and peripheral blood mononuclear cells (PBMCs) were collected from healthy individuals. We analysed the cytokine production and pro…