Aggregation, cell

Transmittance can be used to monitor aggregation. As the cells aggregate, there are fewer total particles to scatter light and, hence, more light is transmitted. This is the same principle behind aggregometers. We monitor this transmittance change on the SLM fluorometer (28). 

In addition to bulk liquid turbulence effects, suspended particles maybe involved in collisions with one another or with solid surfaces within the vessel. This phenomenon has been extensively studied in micro-carrier cultures [60] and appears to be significant at high concentrations [61]. Rosenberg [69] and Meijer [72] applied the approach of Cherry and Papoutsakis [60] to the study of collision phenomena involving spherical plant cell aggregates of 190 and 100 pm, respectively. In both cases it was concluded that for typical biomass concentrations, particle-particle interactions were of less significance than particle-impeller collisions. 

The expansion index [51,102,103], defined as the ratio of cell fresh weight to dry weight evaluated at the time of maximum fresh weight, is a more qualitative indicator of changes in cell/aggregate size, under various cultivation conditions. Wongsamuth and Doran [58] identified the filtration characteristics of suspensions of Atropa belladonna, specifically cake permeability, which is at least partially related to morphology, as a useful indicator of shear effects. 

Jurkat cells Aggregation-dependent cytotoxicity Contaminant-dependent cytotoxicity [163]... 

The best examples of pleiotropy have been provided by developmental biologists. Two examples illustrate the pleiotropic action of developmental genes. Sonic hedgehog participates in the formation of the different cell types that form the neural tube, in limb development and in somitogenesis, a process by which mesodermic cells aggregate to form bones and muscles. 

Morgan JM. A protocol for preparing cell suspensions with formalin fixation and paraffin embedding which minimises the formation of cell aggregates. J Cell. Pathol. 2001 5 171-180. 

The ES cells were encapsulated in the PMBV/PVA hydrogel by the same method used for the L929 cells. In general, ES cells form a cell aggregate called an embryoid body in suspension culture. However, it was observed that the encapsulated ES cells in the hydrogel did not form any embryoid body for 72 h. 

On the other hand, cell immobilization on carriers definitively improves bioreactor efficiency. Cell aggregation in a biofilm structure increases process stability and tolerance to shock loadings. A proper selection of operating conditions allows... 

ES cells aggregated into embryoid bodies and propagated in growth factors, including platelet-derived growth factor, differentiate rapidly to include CNS glial cells. 

Length and size of CNTs seriously affect their cytotoxicities (Sato et al., 2005 Cui et al., 2007). CNTs of 825 nm in length caused stronger inflammation in human acute monocytic leukemia cell line THP-1 than CNTs of 220 nm in length, as shown in Fig. 9.5. However, histological observation as shown in Fig. 9.6, showed that no severe inflammatory response such as necrosis, white cells aggregates, etc. This result indirectly shows that CNTs can cause noninflammatory damage to local tissues. 

A-octanoyl-L-homoserine lactone, OHL or C8-HSL Vibrio fischeri Ralslonia solanacearum Yersinia pseudotuberculosis Bioluminescence. Swimming motiliy, cell aggregation, biofilm maturation... 

Sharpless, T., Traganos, F., Darzynkiewicz, Z., Melamed, M.R., Flow cytometry Discrimination between single cells and cell aggregates by direct size measurement. Acta Cytol 19, 577-581 (1975). 

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