Phenotypic Expression and Differentiation: in vitro Chondrogenesis
Any in vitro analysis of differentiation should take into account three important factors. One is the artifactual nature of the in vitro conditions. The very nature of the culture methodology creates an artifact. This is not meant to imply a deprecation of the study of a created artifact, for in many instances much useful information has been obtained from such studies. The investigator must be aware as to how much transference may be given to in vivo phenomena from in vitro studies. Another factor to take cognizance of is that negative aspects of differentiation in vitro (i. e. “dedifferen-tiation”, or the failure of differentiation) may not be a manifestation of a basic mechanism of differentiation. Observations of this sort may usually be ascribed to the fault of the experimenter and the conditions given the tissue in its foreign environment. A third point to be considered is that the phenotypic expression of differentiation may not be obvious to the observer and may require refined techniques of assay. A cell or tissue that appears “undifferentiated” may actually possess a differentiated metabolic pattern.
KeywordsSpinal Cord Chondroitin Sulfate Metabolic Pattern Neural Arch Cartilage Formation
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