Recombinant Enolase of Trypanosoma cruzi as a Novel Vaccine Candidate against Chagas Disease in a Mouse Model of Acute Infection.

Trypanosoma cruzi is the protozoan parasite that causes Chagas disease, which is considered by the World Health Organization to be a neglected tropical disease. Two drugs exist for the treatment of Chagas disease, nifurtimox and benznidazole; they are only effective in the acute phase, and a vaccine is currently not available. In this study, we used the recombinant enolase from T. cruzi H8 strain (MHOM/MX/1992/H8 Yucatán) (rTcENO) and its encoding DNA (pBKTcENO) to immunize mice and evaluate their protective effects in an experimental murine model of acute phase infection. Our results showed that mice vaccinated with rTcENO or its encoding DNA were able to generate typical specific antibodies (IgG1, IgG2a, and IgG2b), suggesting that a mixed Th1/Th2 immune response was induced. The parasite burden in the blood was reduced to 69.8% and 71% in mice vaccinated with rTcENO and pBKTcENO, respectively. The group vaccinated with rTcENO achieved 75% survival, in contrast to the group vaccinated with pBKTcENO that showed no survival in comparison to the control groups. Moreover, rTcENO immunization elevated the production of IFN-γ and IL-2 after the parasite challenge, suggesting that the Th1-type immune response was polarized. These results indicated that rTcENO could be used as a vaccine against Chagas disease.

Sperm morphological features associated with chronic Chagas disease in the semen of experimentally infected dogs.

The presence of trypanosomatids in the reproductive systems of different mammals (causing genital lesions in the acute stage of the disease) may predispose the animals to low semen quality. However, there are no studies examining the alterations in the sperm morphological features in the chronic stage of Trypanosoma cruzi infection. Knowledge of these aspects is important to understand the other ways of transmission of the Chagas disease. Progressive motility, mass motility, concentration, and sperm morphology of 84 ejaculates of dogs that were chronically infected with T. cruzi were evaluated. Most of the findings were consistent with the reference values and with those obtained from healthy control dogs. The scrotal circumference was not correlated with spermatozoa concentration in the infected animals. In conclusion, the T. cruzi Ninoa (MHOM/MX/1994/Ninoa) strain does not cause significant alterations in the semen quality of dogs experiencing chronic Chagas disease (at concentrations of 5 × 10(4) to 1 × 10(6) parasites per animal).

Multiple extrauterine pregnancy with early and near full-term mummified fetuses in a New Zealand white rabbit (Oryctolagus cuniculus).

Extrauterine pregnancy (EP) is infrequent in mammalian species and occurs when fertilized ova implant and develop outside the uterus. A common outcome is abdominal pregnancy resulting in mummified fetuses (lithopedia). Here we describe an unusual case of abdominal pregnancy with early and near full-term lithopedia. Macroscopic findings supported the diagnosis of lithopedia with distinct age differences and facilitated further characterization of primary ectopia and risk factors leading to this occurrence.

Desarrollo de un modelo canino de hipertensión ventricular derecha crónica progresiva / DEvelopment of a canine model to produce chronic, progressive right ventricular hypertension

Introducción: En modelos animales se ha producido hipertensión ventricular derecha ocluyendo la arteria pulmonar con bandas hechas de silastic, lino, tygón, o teflón. Estos procedimientos no permiten una oclusión gradual y progresiva que remede lo observado en la condición clínica de hipertensión arterial pulmonar e hipertensión ventricular derecha crónica. El objetivo del presente estudio es crear un modelo donde la obstrucción progresiva sea factible. Material y métodos: Diseñamos tanto un programa de adquisición de datos hemodinámicos como un dispositivo oclusor hidráulico (DOH) del tronco de la arteria pulmonar que permite un control externo de la presión ventricular deseada. Estudiamos durante 6 meses, a 12 perros mestizos sanos de 18 a 28 kg de peso. Realizamos mediciones hemodinámicas cada 2 meses, en condición basal, a 40 mmHg y a 60 mmHg de presión sistólica del ventrículo derecho (PSVD), respectivamente. Resultados: El programa facilitó el análisis instantáneo de múltiples variables hemodinámicas. A 60 mmHg de PSVD, la presión diastólica final del ventrículo derecho incrementó de 4.2 ñ 0.4 mmHg a 13.2 ñ 1.1 mmHg, p < 0.000, el gasto cardiaco ajustado al peso del perro disminuyó de 0.16 ñ 0.03 L/min/kg hasta 0.09 ñ 0.01 L/min/kg, p < 0.000 y la presión diastólica final del ventrículo izquierdo, incrementó de 7.4 ñ 0.8 mmHg a 16.3 ñ 2.8 mmHg, p < 0.000. El dispositivo mantuvo en el tiempo la PSVD requerida. La confiabilidad por coeficiente de correlación intraclase fue de 0.83, P < 0.005. Conclusiones: El modelo de hipertensión ventricular derecha crónica está creado. El programa de captura hemodinámica permite un análisis versátil. El DOH es confiable para mantener la PSVD en el tiempo.