Prevalence and severity of dental caries in Costa Rican schoolchildren: results of the 1999 national survey.

UNLABELLED: In 1987, Costa Rica implemented a comprehensive national salt fluoridation programme using sodium fluoride (225-275mg F/kg salt). AIM: To describe dental caries prevalence and severity in Costa Rican children in 1999. METHODS: Eight calibrated examiners (inter-examiner Kappa = 0.70 or higher) recorded information on dental caries, treatment needs, enamel fluorosis, and dentofacial anomalies for schoolchildren aged 6-8,12, and 15-years (N=3758). The survey utilised a multistrata probability sample with fixed allocation to represent seven regions of the country. RESULTS: The overall mean dmft for age 6-8 years was 3.32. The DMFT for age 12 was 2.46 and for age 15 was 4.37. Regional differences were observed; for example, the DMFT at age 12 years ranged from 1.93 to 3.86. Compared with pre-fluoridation data collected in 1984, schoolchildren aged 12 years, experienced a 28 per cent decrease in caries prevalence (100 per cent to 72 per cent) and a 73 per cent decrease in severity (DMFT from 9.13 to 2.46, representing an 8.3 per cent compound annual per cent reduction). CONCLUSIONS: Between 1984 and 1999, Costa Rican schoolchildren experienced substantial reductions in caries prevalence and severity. Many factors may be involved in this decline, but the most important appears to be exposure to fluoridated salt.

Postexposure immunoprophylaxis of primary isolates by an antibody to HIV receptor complex.

mAb B4 is a monoclonal antibody directed against HIV receptor complex. The antibody had broad neutralizing activity against HIV and provided postexposure prophylaxis to hu-peripheral blood leukocyte (PBL)-severe combined immunodeficient mice and chimpanzees. B4 recognized a complex receptor site for HIV on the T cell surface that includes CD4 and also may be influenced by interaction with HIV coreceptors. mAb B4 preferentially neutralized primary HIV-1 isolates compared with T cell line-adapted strains, including syncytium-inducing and non-syncytium-inducing phenotypes, representatives from HIV-1 subtypes A-G, as well as HIV-2, simian immunodeficiency virus, and chimeric simian/human immunodeficiency virus (SHIV). Neutralization was demonstrated in both pre- and postinfection models. The administration of mAb B4 after infectious challenge totally interrupted the infection of hu-PBL-severe combined immunodeficient mice by PBL-grown HIV-1 and the infection of chimpanzees by chimp-adapted HIV-1. This mode of protection suggested that the anti-HIV receptor antibody is efficacious for prophylaxis after exposure to HIV and for prevention of maternal transmission and may be an effective antiretroviral agent for treatment.

Active and passive immunization against HIV type 1 infection in chimpanzees.

Several vaccine strategies have been developed to prevent primary infection with human immunodeficiency virus (HIV), and some of the candidate vaccines have been tested in chimpanzees to determine their safety, efficacy, and to delineate immune correlates of protection. To date, more than 25 vaccines representing active and passive immunization strategies have been evaluated in the chimpanzee model. Efficacy of a given vaccine was based on protection against primary infection with HIV after intravenous or mucosal challenge with cell-free or cell-associated virus. Based on the results from a majority of the studies, neutralizing antibodies appear to play a major role in preventing primary infection with HIV.