Surfaces, tissue culture

Animal cell cultures that are initiated from cells removed directly from the animal are called primary cultures (Figure 2). Primary cultures include both explant cultures (i.e., cultures initiated from small pieces of intact tissue), as well as cultures initiated from preparations of individual or dispersed cells (obtained from intact tissue by mechanical or proteolytic dismption). Nerve fiber explant cultures in blood plasma were among the earliest types of tissue cultures (Harrison, 1907). Cells grow out from such tissue explants and form a single layer of cells completely filling the tissue culture vessel surface. Such cell cultures are called confluent monolayers. Confluent monolayers can then be treated with trypsin, so as to remove the individual cells from the culture vessel surface. The resulting cell suspension is then transferred into other culture containers, so that more viable monolayer... 

Figure 6, Polarized epithelial cells in culture. Epithelial cells in culture possess an apical surface with microvilli that faces the tissue culture medium (equivalent to the lumenal side of the cells in vivo), and a basolateral surface that faces the tissue culture dish (equivalent to the blood side of the cells in vivo).

Initially, the cytotoxicity against chick embryo fibroblasts of BPA, tyrosine, tyrosine dipeptide, and the dipeptide derivatives used in the synthesis of the polymers shown in Fig. 7 were evaluated in a comparative experiment (43). The surface of standard tissue culture wells was coated with 5 mg of each test substance. Then the adhesion and proliferation of the fibroblasts was followed over a 7-day period. Among all test substances, BPA was clearly the most cytotoxic material. Monomeric tyrosine derivatives containing the ben-zyloxycarbonyl group were also cytotoxic, while tyrosine itself, tyrosine dipeptide, and most of the protected dipeptide derivatives did not noticeably interfere with cell growth and adhesion and were therefore classified on a preliminary basis as possibly "nontoxic."... 

In a separate study [88], we synthesized EGF fused to a polystyrene-binding peptide [101] (EGF-PSt) that could be immobilized on the surface of a tissue culture polystyrene dish. This surface also permitted efficient expansion of NSCs. Thus, EGF-PSt can be used to produce large quantities of pure NSCs in standard laboratories. 

Fluorescence Labeling of Surface Antigens of Attached or Suspended Tissue-Culture Cells... 

Plate 2x10 WT or CD154 NIH3T3 irradiated and growth arrested cells on 60 mm tissue culture dishes in 5 ml DMEM and incubate overnight to allow the cells to attach on the surface of the tissue culture dishes. 

WT N1H3T3 cells are more prone to detach than CD154 N1H3T3, so detaching CLL cells from the WT N1H3T3 cells requires extra care. If discontinuities or ruptures in the layer of fibroblasts are noticed, CLL cells may be seeded at this step in 60 mm culture dishes for 2 h to allow possible NIH3T3 cells present in the sample to reattach on the surface of the tissue culture dishes. The tissue culture dishes are then incubated in a humidified atmosphere of 5% CO2 at 37°C. Afrer incubation, examine the tissue culture dishes for the presence of adherent cells and carefully collect the CLL cells in an appropriate sterile tube. 

A wide variety of parameters can directly affect the chemical and physical characteristics of a plasma, which in turn affect the surface chemistry obtained by the plasma modification. Some of the more important parameters include electrode geometry, gas type, radio frequency (0-10 ° Hz), pressure, gas flow rate, power, substrate temperature, and treatment time. The materials and plasmas used for specific biomedical applications are beyond the scope of this text, but the applications include surface modification for cardiovascular, ophthalmological, orthopedic, pharmaceutical, tissue culturing, biosensor, bioseparation, and dental applications. 

Fig. 2. Effect of serum concentration on the attachment and spreading of BHK-21 cells onto TCP2 surface. BHK-21 cells were seeded in media containing the indicated concentrations of intact serum (open squares), Fn-depleted serum (triangles). Vn-depleted serum (circles), or serum-free medium alone (the single closed square) and the attachment panel (A) and spreading panel (B) of the cells were determined after 90 min culture on TCP (panel (A, B)) Mean SEM. (Reproduced from J. Biomed. Mater. Res. [Ref. 11 Role of serum vitronection and fibronectin in adhesion of fibroblasts following seeding onto tissue culture polystyrene] through the courtesy of John Wiley Sons, Inc.) BHK-21 Fibroblast cell lines from Baby Hamster Kidney 2 Similar results on Primaria are also presented in [Ref 11]...

As was stressed by Professor Ubbelohde, in the process of cell recognition not only the lateral diffusion of the binding sites has to be considered, but also the mechanical effects resulting from the local change of surface tension, inducing convection at the cell surface. It is well known, in the cell-to-cell contact inhibition of motion, in tissue culture, that a cell approaches another cell by touching it by means of microvilli and that this process can be affected when adding surfactants to the culture. Now the point is, What is the relative importance of both diffusion and convection Well, in binary surface films, it was observed that the transport process induced by two-dimensional convection is much more rapid than the two-dimensional diffusion. 

Cloning can also be performed using a FACS. Although a powerful technique, it is available to only a limited number of laboratories because of the cost of the equipment. Antigen coupled to a fluorescent marker is incubated with the cells. Cells with surface immunoglobulins of relevant specificity can then be isolated and sorted into individual tissue culture wells. 

Isolated animal cells in tissue culture, no matter how highly differentiated, tend to revert quickly to one of three basic types known as epitheliocytes, mechanocytes, and amebocytes. Epitheliocytes are closely adherent cells derived from epithelial tissues and thought to be related in their origins to the two surface layers of the embryonic blastula. Mechanocytes, often called fibroblasts or fibrocytes, are derived from muscle, supporting, or connective tissue. Like the amebocytes, they arise from embryonic mesenchymal tissue cells that have migrated inward from the lower side of the blastula (Chapter 32). Neurons, neuroglia, and lymphocytes are additional distinct cell types. 

Ap tamers can be selected in various ways. The most frequently used approaches are affinity chromatography [21] and modified cellulose filtration [4,22]. The choice of method depends on the properties of the target (for example, its capability to be immobilized on a matrix or to be bound to modified cellulose filters) and the aim of selection. If the desired aptamers should, for example, bind molecules on the surface of intact cells, the selection scheme should employ these cells adhering to the surfaces of tissue culture flasks [23]. 

Figure 1. Fibroblast cells as seen by stereoscan microscopy Left Surface of cell in tissue culture (X 18,000)...

Numerous surface-active molecules have been studied as GI absorption promoters in a wide variety of testing conditions, including model membranes, everted intestinal sacs, tissue cultures, intestinal epithelia in diffusion chambers, intact animals, and humans. The physical properties of a chemical enhancer may be strongly dependent on the interactions with the endogenous GI components such as bile salts, pH, and bacteria. Thus the in vitro experiments on enhancing GI absorption are not necessarily predictive of the behavior of the promoter in animals or humans, and we will mainly focus on summarizing results from in vivo studies. 

Plasma oxidation of fibers is an example of a treatment aimed at chemically modifying the surface to improve a surface property. These treatments have wide application in industry and are used to improve wettability and printability of plastics, the adhesion of materials to surfaces including tissue culture cells, and a variety of other applications (36). 

Deplete the cell suspension of monocytes and macrophages by incubation in 150-cm2 tissue culture flask for 2 h at 37°C (monocytes and macrophages will adhere to the surface of the flask). Wash off the nonadherent cells with PBS buffer and collect. 

Toward the Emergence of Surface Models After a Century of Tissue Culture. 82... 

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