Maintenance of Acanthamoeba culbertsoni by cryopreservation.

In order to determine the viability of trophozoites of Acanthamoeba culbertsoni under cryopreservation conditions, cultures in serum-casein-glucose-yeast extract medium were subject to 5%, 7.5%, and 10% concentrations of dimethylsulfoxide (DMSO). With the methodology followed, the percentages of recovery varied between 75.6% and 86.6% with DMSO at 10%, between 54.5% and 73.5% with DMSO at 7.5%, and between 43.6% and 68.5% with DMSO at 5%. The amebae were kept in liquid nitrogen for 30-210 days. The highest viability of trophozoites was founded when DMSO was used at a final concentration of 10% and an equilibrium temperature of 4 C. Gross cultural or morphological changes were not noted in trophozoites thawed from frozen suspensions.

Effect of three immunostimulants on the resistance against Trichinella spiralis infection in mice. (preliminary report).

Twenty eight NIH mice were divided into four groups of seven animals each. Mice in groups were injected intraperitoneally with Freund's complete adjuvant (FCA), Concanavalin A (Con A), Equimune (EI) and phosphate buffered saline (PBS), respectively, 7 days before infection with 300 Trichinella spiralis infective larvae per animal. Forty two days after infection all mice were sacrificed and processed by artificial digestion to determine the number of larvae per gram (LPG) of muscle tissue. The mean +/- SD of LPG obtained were 59.8 +/- 13.1, 17 +/- 8.5, 3.3 +/- 6.2 and 71 +/- 11.5 for groups FCA, Con A, EI, and PBS, respectively. Significant reductions in larvae worm numbers, compared with non-treated controls, were 76% and 95.3% in groups Con A and EI, respectively.