Effects of adjuvants and Toxoplasma gondii antigens on immune response and outcome of peroral T. gondii challenge

Toxoplasma gondii antigens and adjuvants administered parenterally and perorally were tested for their ability to produce serum antibody to T. gondii, to enhance peritoneal microbicidal capacity for T. gondii, and to prevent acquisition of infection by T. gondii ingested subsequently. N-acetylmuramyl-L-alanyl-D-isoglutamine-6-0-stearoyl (MDP) incorporated into liposomes administered intramuscularly to mice with 80 micrograms of T. gondii antigens and the synthetic adjuvant N,N-dioctadecyl-N',N'bis (2-hydroxyethyl) propanediamine (CP 20,961) administered intramuscularly to mice with 80 micrograms of T. gondii lysate antigens produced the highest titres of antibody to T. gondii in sera (i.e., the mean +/- S.D. of the log2 of the reciprocal of the antibody titre to T. gondii measured by Sabin Feldman Dye test was 9 +/- 2 in sera of mice that received T. gondii antigens plus MDP and was 8 +/- 1 in sera of mice that received T. gondii antigens plus CP 20,961). No orally administered preparation produced high titres of serum antibody to T. gondii. None of the preparations which were tested protected mice against infection with T. gondii when cysts containing the parasite were administered by mouth subsequently or enhanced macrophage microbicidal capacity between two and three weeks after the last immunizations. These experiments demonstrate that presence of Toxoplasma antibody (i.e., when log2 of the reciprocal of Toxoplasma antibody titres is 10 or less measured by Sabin Feldman dye test) does not protect mice against dissemination of ingested T. gondii from the gastrointestinal tract. The method of peroral challenge with T. gondii developed for this study is useful for examining effects of other potentially protective regimens in preventing acquisition of ingested T. gondii.     

Perceived influence of different information sources on the decision-making of internal medicine house staff and faculty

To determine the extent to which different sources of information are perceived to influence common medical decisions, 10 interns, 22 senior residents and 9 faculty general internists rated the degree of influence of house staff, general internists, subspecialists, conferences, journal reading and past experience on their decisions concerning primary prevention (vaccination), secondary prevention (screening) and drug therapy. Analysis of variance of their questionnaire data supports the following conclusions: physicians at different stages of training rely on different sources of information; as physicians advance in training the influence of generalists wanes while that of subspecialists increases; subspecialists and past experience are perceived as primarily affecting therapeutic decisions; primary prevention appears least subject to influence by prevailing information sources; and the preference for reading begins early and increases as physicians advance in training. These data suggest that designing effective medical education requires considering the level of the physician's training and the nature of the medical decision.