A rapid group A beta-hemolytic streptococci (GAS) antigen detection test using latex agglutination (Directigen?, Becton Dickinson) was compared with a conventional culture method for the direct detection of GAS from throat swabs.
The optimal temperature and light intensity for DHA production were determined and a maximal DHA production of 4.3 mg-l was achieved, twofold greater than that obtained using conventional culture methods.
The assay was more sensitive and could be completed within 3 h, as opposed to several days when conventional culture methods were used.
Depending on the physiologic oxygen tension and the histologic origin of a particular cancer type, the in vitro chemosensitivity of many drugs obtained with the conventional culture system could be inadequately assessed.
As experiments in conventional culture dishes continued to fail, new cell and tissue culture methods had to be developed.