Vaccination against severe hepatosplenic disease in schistosomiasis japonica: a hypothesis

Manifestations of serious disease in chronic schistosomiasis such as portal hypertension, collateral circulation and hepatosplenomegaly are ascribed to T cell-dependent obstructive granuloma formation with subsequent fibrosis principally in the liver. Collagen synthesis and tissue fibrosis may also result from indirect effects of T cell dependent macrophage activation but also from direct effects of eggs productions. Mature eggs are known to be a rich source of "immunopathologic" antigens. It is proposed that antibodies, through their effects on both mature and immature eggs, may markedly decrease opportunities for expression of immunopathologic responses. The hypothesis is that antibodies of certain specificities and certain istotypes can inhibit embryonation of immature and/or effect early or accelerated destruction of mature eggs. The disease modulating consequences of these stem from inhibition of sustained production and release of immunopathologic antigens. The anti-immunopathologic effects being termed "anti-embryonation immunity" (directed against immature eggs) and "anti-miracidial immunity" (accelerated desctruction of mature eggs). On theoretical grounds, sensitization of hosts for anti-embryonation immunity would be a particularly effective means of vaccinating against severe hepatosplenic disease. Such a vaccination strategy could also lead to reduced transmission of infection. It should also inhibit production of egg products with effects in the liver such as hepatotoxicity and promotion of collagen synthesis. The hypothesis emphasizes the consequences of the immune responses on the source of immunopathologic antigens (i.e the egg) in modulation of granuloma formation and disease abatement. The alternative, and in our view, less attractive strategy of vaccination for anti-immunopathology, is to promote immuregulatory responses (e.g. suppressor T cells) which operate to inhibit immunopathologic effector cells and antibodies.(Summary)

Bleeding patterns and acceptability among Norplant users in two Asian countries.

Changes in menstrual bleeding patterns are the most frequent reason for discontinuing NORPLANT during the first year of use. Although NORPLANT is used by more women in Asia than in any other region, the changes that occur among these women are not well documented. In pre-introductory clinical trials of NORPLANT in the Philippines and Sri Lanka, 175 women were enrolled with greater than 95% continuing the method after one year. Daily menstrual bleeding calendars were kept by 94% of subjects for nine months and by 66% for one year. In contrast to findings in previous studies which showed that approximately 60% of NORPLANT users had bleeding disruptions in the first year of use, almost all of these women experienced bleeding disruptions. In a one-year study of menstrual pattern changes, increased bleeding was found to occur with the same frequency as reduced bleeding. However, the changes experienced by the Asian women tended to be decreases, rather than increases, in menstrual bleeding.