Organ culture methods

A method of assessing the toxicity of implants has been proposed based on the effects on cell ultrastructure in organ cultures, on cell surface characteristics, and cell population doubling times. The effects have been correlated with hemorrhage, fibrosis, and necrosis, respectively (103). Poly-e-caprolactone was stated to give minimal tissue reaction and could not be scored in these tests. 

But once an elective culture method for a particular microbe is available, it may safely be concluded that this organism will also be found in nature under conditions corresponding in detail to those of the culture, and that it will carry out the same transformations. (Van Niel 1955)... 

Studies of sequence information from organisms in soil microhabitats and then-gene expression under different management conditions will provide guidelines for designing new and improved culturing methods that resemble their natural niches. 

Modern approaches based on the use of molecular techniques presumed to circumvent the need for culturing prokaryotes, fail to provide sufficient and reliable information for estimation of prokaryote diversity. Many properties that make these organisms important members of the living world are amenable to observation only through the study of living cultures. Since current culture techniques do not always satisfy the need of providing a balanced picture of the microflora composition, future developments in the study of bacterial diversity should include improvements in the culture methods to approach as closely as possible the conditions of natural habitats. Molecular methods of microflora analysis have an important role as guides for the isolation of new prokaryotic taxa. 

In Vitro Systems. Different biochemical approaches provide a variety of methods for comparing and evaluating fiber toxicity. Organ cultures, cultured cells, and cells in suspension from humans and animals can be exposed to fibrous materials or, alternatively, cells from treated animals, bacterial cells, and so on can be used. Many hundreds of experiments have been performed, but it is difficult to apply the results, and in many cases extrapolation to humans is not warranted. Nevertheless, cell systems provide excellent data on which to base our understanding of the mechanisms related to fiber-induced disease a few selected examples follow. 

The implementation of animal test protocols in the 1980s has been accompanied by the development of a host of alternative methods to study adverse effects of chemicals on reproductive and developmental parameters. For example, rat whole embryo culture stems from the seventies (16), as does the rat limb bud organ culture (17) and rat limb bud and brain micromass was developed in the eighties (18). An elegant nonvertebrate alternative model used regeneration of polyps of Hydra atUnuata from dissociated cells (19). Animal-free in vitro alternatives include those employing the proliferation of a human embryonic palatal mesenchymal cell line (20), the attachment of a mouse ovarian tumor cell line (21), and the differentiation of a neuroblastoma cell line (22) and a embryonal carcinoma cell line (23). Various overviews of methods have been published over the years (24). The predictability of... 

The choice of cell culture method for cytotoxicity studies for a certain substance depends on the target cells and assay duration. Organ, spheroids, suspension cells, flask surface, and multi-well plate monolayers, as well as agar surface cultures can be employed. 

Organ cultures allow tissue integrity and intercellular relations to be maintained, with a closer approximation to the in vivo situation, compared with other methods. Nevertheless, reliable quantification of the effects caused by a pharmaceutical compound is more difficult because of variability between replicates. 

Fisher RL, Shaughnessy RP, Jenkins PM et al. (1995) Dynamic organ culture is superior to multiwell plate culture for maintaining precision-cut tissue slices. 1. Optimization of the tissue slice culture. Toxicol Methods 5 99-113 Forster RP (1948) Use of thin kidney slices and isolated renal tubules for direct study of cellular transport kinetics. Science 108 65-67... 

Primary cells can be defined as cells taken directly from an organism and adapted to survive and eventually grow in culture, at least for a limited period. In fact, with the exception of some cells derived from tumors, primary cells have limited lifespans in culture. Cells can be isolated from tissues for ex vivo culture in several ways. They can be released from soft tissues by enzymatic digestion with enzymes such as collagenase, trypsin, or pronase that break down extracellular matrices. Alternatively, in the explant culture method, pieces of tissue are placed in growth media and the cells that grow are available for culture. 

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