| Abstract | Radioisotope applications in experimental tuberculosis range from in vitro studies with labeled microbes to in vivo studies with labeled compounds in tubercular animals. The in vitro studies with labeled microbes are far more numerous than the in vivo investigations with labeled compounds or microbes. I. Mycobacteria can be labeled in the following manners: a. Metabolic uptake of a labeled nutrient, introduced into the culture medium; this is the case of all microbial metabolites (32P, 35S, 14C-compounds, 3H, etc.), or metabolic analogues (relatives), such as Selenium 75 for sulphur, Caesium 137 for potassum, Strontium 90 for calcium. Finally, in some cases, metabolites of host tissues can be incorporated by the growing microbe; this is the case of 14C-labeled cholesterol or estrogens. b. "In vitro" labeling of suspensions of adult cells (non-radioactive) a with a radioactive element, which is selectively combined to a microbial constituent; this is the case of iodination of microbial cells, or binding of rare earths to the PO4 free groups of nucleic acids (144Ce, 140La, etc.) |
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