Aggregation of cells

The macula densa is a dense aggregation of cells in the distal tubule of nephrons facing the glomerular tuft of capillaries. These cells sense the salt content of the distal tubular fluid and adjust glomerular perfusion and renin secretion accordingly. 

Aggregates of cell bodies within the medulla of the brainstem form the medullary respiratory center, which has two distinct functional areas ... 

Our previous studies showed that CNTs exhibit marked cytotoxicity (Cui et al., 2005 Tian et al., 2006). For example, SWCNTs can inhibit HEK293 cell proliferation, decrease cell adhesive ability in a dose-and time-dependent manner as shown in Fig. 9.7. HEK293 cells also exhibit active responses to SWCNTs such as secretion of some 20-30 kd proteins to wrap SWCNTs, aggregation of cells attached by SWCNTs and formation of nodular structures as shown in Fig. 9.8. Cell cycle analysis showed that 25pg/ml SWCNTs in medium induced Gt arrest and cell apoptosis in HEK293 cells as shown in Fig. 9.9. Biochip analysis showed that SWCNTs can induce up-regulation expression of cell cycle-associated genes such... 

Further, rafts altoed by stimulated ASM activation may be involved in non-receptor-mediated signaling. For instance, UVC triggers aggregation of cell surface CD95 (RehemtuUa et al, 1997), which might be sufficient to initiate signaling of CD95 at least under stress conditions. Likewise, it has... 

In most processes, steps 1, 3, 5 and 6 are in pseudo steady state and the mass transfer is governed by diifusion through the gas-liquid layers (steps 2 and 4). An additional step can appear if one deals with aggregates of cells (pellets), but we will not examine this case. 

Liver Nodule A small node, or aggregation of cells within the liver. 

More complex alternative developmental programs are followed by colonial forms of bacteria such as the myxobacteria. The life cycle involves aggregation of cells and formation of fruiting bodies as well as sporulation.185... 

Although plant tissue culture should refer only to those of unorganized aggregates of cells, it is commonly used as a collective term to describe all types of in vitro plant cultures (George and Sherrington, 1984). 

Orifice The orifice is the exit opening in a flow cell or nozzle. Its diameter can, in general, range from 50 to 300 pm. Cells or aggregates of cells anywhere near as large as the orifice will block it. The diameter of the orifice affects the possible drop frequencies for flow sorting. 

Spheroids are formed through spontaneous aggregation of cells, and their use allows the analysis of the effects of three-dimensional distribution of cells to test compounds, without the disadvantages presented by organ culture. Parameters such as penetration barriers in non-vascular areas and metabolic and proliferation gradients can be studied by use of this model. 

Fig. 14.42. Qualitative representation of percentage change in electrophoretic mobility from control value as a function of concentration of chemical, showing regions of stability or aggregation of cells. (Reprinted from S.

The ecdysteroid-responsive Kc permanent cell line was established from disrupted embryos of D. melanogaster [188], Consequently, it is not known what in vivo cell type (if any) they represent. However, the response (aggregation of cells, cessation of division and the formation of axon-like projections) is characteristic and can form the basis of a somewhat time-consuming bioassay [189], which has been used to compare the biological activities of 60 steroids, most of which were inactive. The biological activities of a number of ecdysteroids in this Kc-H cell bioassay are summarised in Table (4). 

The aggregation of cells in suspension culture leads to a heterogeneous population that confound the analysis and operations of the reactor types mentioned above in many cases. For non-growth associated products, immobilization of cells provides a... 

Hyperlayer-DEP-FFF has the advantage of making better use of the parabolic velocity profile of the fluid since flow at different heights in the channel is exploited as in steric-DEP-FFF the particles essentially stay in the layer near the channel wall. In addition, the hyperlayer mode minimizes the adhesion of the particles to the channel wall, which also suppresses the aggregation of cells into pearl-chains. 

Aggregation of cells in suspension. The method was originally set up by Orr and Roseman (1969), and next modified by Tao et al. (1983) to measure differences in homotypic adhesiveness due to cell surface carbohydrates changes. A similar assay was also set up by others in order to evaluate how different parameters could influence the aggregation ability of BHK cells in culture (Urushihara et al., 1976 Takeichi, 1977). These methods measure the propensity of a... 

A tissue is an aggregation of cells of common source, structure and function in intimate union. 

Suspension culture A type of culture in which cells, or aggregates of cells, multiply while suspended in liquid medium. 

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