Cell-based therapies toxicity studies

Current data support the use of concurrent over sequential or alternating chemotherapy and radiation therapy. The optimal delivery of concurrent chemoradiation is still under study. Early delivery of radiation therapy may decrease dissemination by killing the chemoresistant tumor cells prior to their distant seeding. Late delivery of radiation therapy possibly reduces toxicities and full chemotherapy doses can be delivered. However, even with increased toxicity, improved survival rates help establish as standard early delivery of concurrent radiation with platinum-based chemotherapy. 

From the results, most of the extracts tested were relatively non-cytotoxic, which could be an indicator of some safety aspects of the tested plants, hence justifying the generational uses of these plants in traditional medicine. This information could be a basis for development of safe herbal therapies with fewer or no side effects compared to conventional medicines most of which have been reported to have many side effects. Since only a preliminary screening was done for the reported extracts, there would be a need to carry out further studies on their toxicity and safety margins, and develop standardized herbal formulations based on this. There would also be a need to screen the extracts against a panel of more than one cell line as different cell lines exhibit different sensitivities towards various extracts or compounds. 

Studies with ion replacement indicated that chelation of zinc was the proximal cause of cytotoxicity, and examination of a variety of chelators suggested that those with high membrane permeability were especially apt to produce cell death (Sheridan and Deshpande, 1998). Based on these findings, metal chelators may have a limited use in the therapy of botulinum intoxication since the requirements for efficacy against BoNT are the same ones that promote cellular toxicity. 

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