241Am-Be(α,n) CHARACTERIZATION FOR A NEW LABORATORY FACILITY IN BRAZIL.

The Laboratório de Ciências Radiológicas is developing an irradiator for neutron survey meters calibration. Part of this work is related to the characterization of the neutron source that will be used in the irradiator. Therefore, a source of 241Am-Be(α,n) was characterized according to the following attributes: neutron energy distribution, anisotropy and emission rate. In order to make these values into high-level metrological references traceable by the Bureau International des Poids et Mesures, these measurements were taken at the Neutron Laboratory part of the Laboratório Nacional de Metrologia das Radiações Ionizantes. Results obtained for the source spectrum have strong adherence to the reference spectrum established by ISO 8529-1. The new laboratory for neutron calibration will allow calibration in an approximate ambient dose equivalent ranging 20-4500 µSv/h.

Humoral immunological profile and parasitological statuses of Leishmune vaccinated and visceral leishmaniasis infected dogs from an endemic area.

Dogs represent the major reservoir of Leishmaniao chagasi and vaccination against the canine disease is a potential control strategy. However, seroconversion occurs post-vaccine and hence, there is need to discriminate between the former group and naturally infected dogs. The present study represents a comparison of the humoral immunological profiles of both groups using Leishmania soluble antigen (LSA) and fucose-mannose ligand (FML). For both categories, ear skin samples were evaluated immunohistochemically and through PCR, that was also performed in blood specimens, as well as their ability to infect Lutzomyia (Lutzomyia) longipalpis. All these tests showed negative results for the vaccinated dogs. Differences between groups were observed regarding IgG, IgG2 and IgE absorbances as determined by FML-ELISA, and for IgG1 and IgE absorbances as measured by LSA-ELISA, showing that Leishmune-immunised animals and VL naturally infected dogs present different immunological profiles, even though these differences cannot be used to distinguish between these two groups of dogs.

Efficacy of atovaquone and sulfadiazine in the treatment of mice infected with Toxoplasma gondii strains isolated in Brazil.

The efficacy of atovaquone and sulfadiazine was examined alone or in combination for the treatment of mice infected with six Brazilian Toxoplasma gondii strains previously genotyped using the PCR-RFLP assays of the SAG2 gene, in addition to RH strain. Swiss mice were infected intraperitoneally with 10(2) tachyzoites from each strain of T. gondii and treated with 6.25, 12.5, 25 and 50 mg/Kg/day of atovaquone or 40, 80, 160 and 320 mg/Kg/day of sulfadiazine. In a second experiment, mice were treated with the association of previously determined doses of each drug. Treatment started 48 hours post-infection, and lasted 10 days. The susceptibility of T. gondii to atovaquone and to sulfadiazine was different according to the parasite strain. It was observed strains that are susceptible to atovaquone, and strains that are resistant to it. Type I strains were more susceptible to the activity of sulfadiazine and more resistant to atovaquone. Yet type III strains were susceptible to atovaquone and to sulfadiazine. Association of atovaquone and sulfadiazine presented a synergic effect in the treatment of mice infected with RH type I strain and an additive effect in the treatment of mice infected with one type I strain and with two type III strains.

Influence of the long-term Trypanosoma cruzi infection in vertebrate host on the genetic and biological diversity of the parasite.

The influence of the long-term Trypanosoma cruzi infection in vertebrate host on the biological and genetic properties of the parasite was evaluated. Four T. cruzi isolates obtained from different chronic chagasic dogs infected with Berenice-78 T. cruzi strain during 2 and 7 years were comparatively analyzed. The long-term T. cruzi infection has led to alterations in parasitemia, virulence and pathogenicity of Be-78 strain for mice. These biological parameters varied from low to high in realation to the parental strain. Randomly amplified polymorphic DNA and isoenzyme profiles detected two distinct genetic groups of parasites. The first group included the parental strain and two T. cruzi isolates, and the second group the two other isolates. Interestingly, the isolates of the second group showed a reversibility of the genetic profile to the parental strain after 25 passages in mice. No correlation between the genetic groups and biological properties of the isolates was observed. Our findings confirmed the population heterogeneity of the Be-78 strain, and showed how differently it responds to the long-term infection in the same vertebrate hosts.

Identifying cyclosporine blood levels associated with the prevention of renal transplant rejection: a single-center, randomized prospective study.

Multiple-drug therapy may allow reduced individual drug doses with fewer side effects. Blood levels of cyclosporine (CsA) necessary to avoid rejection may vary with different drug combinations. Fifty-eight kidney transplant patients were randomized into two groups: 25 subjects were assigned to the 4-hour area under the curve (AUC(0-4)) Cohort-the "high arm" (4500 to 5500 ng . h/mL)--1 and 33 to the AUC(0-4) "low arm" (2400 to 3400 ng . h/mL). After CsA introduction, AUC(0-4) was drawn on days 4, 7, 14, 21, 28, 42, 56, 70, 84, 90. We compared the proportion of rejection versus rejection-free patients, according to the CsA exposure. Logistic regression analysis showed that an AUC(0-4) of > or =4000 ng . h/mL or a 2-hour cyclosporine level (C(2)) of > or =1450 ng/mL predicted a rejection-free course among patients not receiving induction therapy. When either basiliximab or thymoglobulin was administered, a C(2) and AUC(0-4) of 1043 +/- 151 ng/mL or 3146 +/- 262 ng . h/mL, respectively, were associated with a rejection-free course. Our findings confirm the need for different CsA levels to prevent rejection according to induction therapy. Induction with either basiliximab or thymoglobulin allows reduced CsA levels during the first 3 months after renal transplantation.

Effects of specific treatment on parasitological and histopathological parameters in mice infected with different Trypanosoma cruzi clonal genotypes.

The goal of this study was to verify the effect of specific treatment on parasitological and histopathological parameters in mice experimentally infected with different Trypanosoma cruzi clonal genotypes. Twenty cloned stocks were selected, representative of the whole phylogenetic diversity of the protozoan and belonging to the clonal genotypes 19 and 20 (T. cruzi I) and 39 and 32 (T. cruzi II). The stocks were inoculated in 40 BALB/c mice divided into four groups: (i) treated with benznidazole, (ii) treated with itraconazole and (iii and iv) untreated control groups (NT) for each drug, respectively. Seven parameters related to parasitaemia curves and histopathological lesions were analysed. Four during the acute phase (AP) and three during both the AP and chronic phase (CP) of infection. Statistical comparison between benznidazole-treated and NT groups for the biological parameters showed significant differences for all genotypes. Benznidazole treatment led to lower patent period, maximum of parasitaemia, day of maximum parasitaemia and area under the parasitaemia curve for all genotypes analysed. Percentage of positive haemoculture during AP and CP was lower for genotypes 19 and 32. Tissue parasitism (TP) and inflammatory process (IP) during AP were lower for genotypes 19 and 32, respectively. In general, itraconazole treatment induced a smaller reduction in these same parameters between treated and NT animals in relation to benznidazole treatment. Our results indicate that phylogenetic divergence among T. cruzi clonal genotypes must be taken in account in chemotherapy and studies dealing with all aspects of the parasite and the disease.

[Profile of HIV-positive women hospitalized in a public maternity ward in Rio de Janeiro]. / Perfil de mulheres portadoras do HIV de uma maternidade no Rio de Janeiro.

AIDS has been scaring the world population for the last decades. The writers of this article decided to investigate and research into the high incidente of women HIV+ hospitalized in a public maternity in the district of Rio de Janeiro, showing the profile of pregnant women from 1987 to 1996. After a thorough analysis of a total of 102 cases this number was eventually broken down showing that the majority of the female population are single, between the ages of 19 and 33 years, have low schooling, mainly housewives and were sexually contaminated. The results show that the affected groups lack the knowledge as to how they could protect themselves against contamination. It is, therefore, of vital importance to take the necessary measures to help prevent contamination and to focus on health education.