title: MULTIPLICATION AND THERAPY OF TOXOPLASMA GONDII IN TISSUE CULTURE.
abstract: Maloney, Emily D. (University of Florida College of Medicine, Gainesville), and Herbert E. Kaufman. Multiplication and therapy of Toxoplasma gondii in tissue culture. J. Bacteriol. 88: 319-321. 1964.-The effect of temperature on the rate of multiplication of the RH strain of Toxoplasma gondii and the results of treatment with pyrimethamine, an antifolic, at various temperatures were studied in tissue culture. At 37 C incubation, the organism was found to have a lag time of 10.5 hr and a mean generation time thereafter of 4.85 hr for binary multiplication during the exponential phase of growth. At 34 C, the lag time was 12 hr and generation time was 5.26 hr. When the organisms were incubated at 31 C, the lag time was 12.5 hr and generation time was 11.1 hr. Treatment of infected monkey kidney tissue cultures with 0.05 mg per 100 ml of pyrimethamine at 37 C for 4 days killed all organisms and permitted survival of the mice which were injected with the cultures. When cultures were incubated at 34 C, a dose of 0.6 mg per 100 ml was required to spare any mice, and with a 31 C incubation even this dose was only slightly effective when therapy was continued for 4 days. If the treatment was prolonged for 7 days before injection of the cultures into mice, however, no difference in therapy with different rates of multiplication was found. Since the rates of multiplication at 34 and 31 C are similar to the rates of multiplication of some naturally occurring strains, these data confirm the fact that prolonged therapy, as used by many, is rational.
mesh_terms: D000818:Animals; D051379:Mice; D010600:Pharmacology; D011739:Pyrimethamine; D012106:Research; D013696:Temperature; D046509:Tissue Culture Techniques; D014122:Toxoplasma; D014124:Toxoplasmosis, Animal
chemical_list: D011739:Pyrimethamine
keywords: EXPERIMENTAL LAB STUDY; MICE; PHARMACOLOGY; PYRIMETHAMINE; TEMPERATURE; TISSUE CULTURE; TOXOPLASMA