O objetivo deste estudo foi comparar a eficiência do sistema automatizado (curva de resfriamento controlada eletronicamente) de congelação de sêmen bovino versus o sistema convencional (curva não controlada) por meio dos parâmetros de qualidade e viabilidade espermática no período pós-descongelação. O sêmen de quatro touros azebuados adultos foram criopreservados simultaneamente em meio tris, gema e glicerol 7%. A avaliação computadorizada do sêmen descongelado detectou os seguintes parâmetros: MP 56,50±22,25%; VAP 34,77±4,25µm/s; VSL 28,17±4,25 µm/s; VCL 58,45±6,85µm/s; STR 82,00±2,31%; LIN 49,50±3,32%, para o sistema automatizado e MP. 57,00±13,11%; VAP 25,75±1,66µm/s; VSL 23,32±1,99µm/s; VCL 63,32±1,79µm/s; STR 82,25±3,59µm/s; LIN 50,00±4,97µm/s para o sistema convencional. Os valores médios das avaliações de integridade de membrana plasmática e integridade acrossomal foram de 54,72±12,55% e 36,13±22,20% para o sistema automatizado e 53,22±13,22% e 47,26±5,74% para o sistema convencional, respectivamente. Com os parâmetros avaliados foi possível identificar que não houve diferença estatística entre os sistemas de criopreservação. Desta forma, a escolha do método de criopreservação do sêmen bovino para utilização direta na propriedade fica a critério do técnico responsável, que deverá se basear na realidade de cada propriedade. Para tanto, sempre se deve considerar que o sistema convencional pode trazer mais variações que o sistema automatizado que, apesar do custo do equipamento, pode garantir repetibilidade nos resultados e consequente qualidade do sêmen bovino criopreservado.

The objective of this study was to compare the efficiency of bovine semen cryopreservation using the controlled-rate freezing machine versus the conventional method (uncontrolled curve) by the parameters of sperm quality and viability in post-thaw period. Semen from four adult crossbreed bulls was cryopreserved in Tris-yolk-glycerol medium. The computer assisted analysis of thawed semen detected the following results: PM 56.50±22.25%; VAP 34.77±4.25µm/s; VSL 28.17±4.25µm/s; VCL 58.45±6.85µm/s; STR 82.00±2.31%; LIN 49.50±3.32%, to automated system and PM 57.00±13.11%; VAP 25.75±1.66µm/s; VSL 23.32±1.99µm/s; VCL 63.32±1.79µm/s; STR 82.25±3.59µm/s; LIN 50.00±4.97µm/s to conventional cryopreservation system. The results of plasma membrane and acrosome integrity evaluation were 54.7±12.55% and 36.13±22.20% for the automated system and 53.22±13.22% and 47.26±5.74% for the conventional system, respectively. The parameters evaluated demonstrated that there was no statistical difference between the cryopreservation systems. Thus, the choice of the bovine semen cryopreservation method to be used on a farm is a responsibility of the technician, and should be based on the reality of each farm. Therefore, it is always necessary to consider that the conventional system of bovine semen cryopreservation can vary more than the automated system, which, despite the cost of the equipment, can ensure repeatability of the results and consequent quality of cryopreserved bovine semen.

We have compared the efficacy of two Leishmania (Leishmania) major vaccines, one genetically attenuated (DHFR-TS deficient organisms), the other inactivated [autoclaved promastigotes (ALM) with bacillus Calmete-Guérin (BCG)], in protecting rhesus macaques (Macaca mulatta) against infection with virulent L. (L.) major. Positive antigen-specific recall proliferative response was observed in vaccinees (79% in attenuated parasite-vaccinated monkeys, versus 75% in ALM-plus-BCG-vaccinated animals), although none of these animals exhibited either augmented in vitro gamma interferon (IFN-<FONT FACE=Symbol>g</font>) production or positive delayed-type hypersensitivity (DTH) response to the leishmanin skin test prior to the challenge. Following challenge, there were significant differences in blastogenic responses (p < 0.05) between attenuated-vaccinated monkeys and naïve controls. In both vaccinated groups very low levels of antibody were found before challenge, which increased after infective challenge. Protective immunity did not follow vaccination, in that monkeys exhibited skin lesion at the site of challenge in all the groups. The most striking result was the lack of pathogenicity of the attenuated parasite, which persisted in infected animals for up to three months, but were incapable of causing disease under the conditions employed. We concluded that both vaccine protocols used in this study are safe in primates, but require further improvement for vaccine application.

Seven rhesus macaques were infected intradermally with 10(7) promastigotes of Leishmania (Leishmania) major. All monkeys developed a localized, ulcerative, self-healing nodular skin lesion at the site of inoculation of the parasite. Non-specific chronic inflammation and/or tuberculoid-type granulomatous reaction were the main histopathological manifestations of the disease. Serum Leishmania-specific antibodies (IgG and IgG1) were detected by ELISA in all infected animals; immunoblot analyses indicated that numerous antigens were recognized. A very high degree of variability was observed in the parasite-specific cell-mediated immune responses [as detected by measuring delayed-type hypersensitivity (DTH) reaction, in vitro lymphocyte proliferation, and gamma interferon (IFN-gamma) production] for individuals over time post challenge. From all the recovered monkeys (which showed resolution of the lesions after 11 weeks of infection), 57.2% (4/7) and 28.6% (2/7) animals remained susceptible to secondary and tertiary infections, respectively, but the disease severity was altered (i.e. lesion size was smaller and healed faster than in the primary infection). The remaining monkeys exhibited complete resistance (i.e. no lesion) to each rechallenge. Despite the inability to consistently detect correlates of cell-mediated immunity to Leishmania or correlation between resistance to challenge and DTH, lymphocyte transformation or IFN-gamma production, partial or complete acquired resistance was conferred by experimental infection. This primate model should be useful for measuring vaccine effectiveness against the human disease.

Seventeen patients proceeding from the municipality of Rio de Janeiro, Brazil presenting with the cutaneous ulcerative form of American leishmaniasis were treated with one ampoule of pentavalent antimony daily for 30 days. With this regimen the individuals doses varies greatly: from 3.8 mg/kg of body weight to 22.3 mg/kg. After five years, patients receiving either a smaller dose or a bigger one, showed the same therapeutic result: cutaneous scars and no mucosal lesions.