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Chronic Chagas' disease represents the result of the interaction between the host and the parasite, producing different clinical features: from a mild disease to a severe heart failure. In the present investigation, we analyzed whether Trypanosoma cruzi strain and/or reinfections in the acute stage, determine changes in the chronic phase (135 days postinfection, d.p.i) that could explain the diverse evolution of cardiac lesions. After infection of albino Swiss mice (n = 170) with 50 blood trypomastigote of the T. cruzi, strain Tulahuen (n = 80) and the isolate SGO-Z12 (n = 90), respectively, and reinfections at 10 and 20 d.p.i. Parasitemia, survival, electrocardiography, affinity and density of cardiac beta-receptors and histopathology of the heart were studied. Parasitemias in reinfected mice were significantly higher than those in single-infected mice. Survival of SGO-Z12-infected group was significantly higher than the other groups (p < 0.01). All Tulahuen-reinfected mice and 55-67% of the infected and SGO-Z12-reinfected groups presented some electrocardiographic abnormality (p < 0.01). Hearts from single-infected mice presented fibber disorganization and necrosis; reinfected groups also exhibited fibber fragmentation and a diminished affinity and a higher beta-adrenergic receptors' density than the other groups (p < 0.05). Therefore, parasite strain and reinfections determine different cardiac damage, and either (or both) of these factors are involved in the severity of the clinical picture and the prognosis of the chronic cardiac disease.

Objectives:This study utilizes a [US] national sample of emergency medical services (EMS) professionals to explore the hypothesis that demographic and work-related characteristics are associated with involvement in ambulance crashes.Methods:In 2004, a cohort of nationally registered EMS professionals was surveyed to determine ambulance crash involvement during a 12-month period. Involvement in an ambulance crash was the outcome variable of interest. Demographics such as age, community size, service type, call volume, time spent in an ambulance, and current sleep problems were analyzed as independent variables. A multivariate logistic regression model identified variables associated with involvement in an ambulance crash within the past year.Results:Surveys were received from 1,775/5,565 (32.0%) participants; 1,297 (73.1%) met the inclusion criteria. A total of 111 (8.6%) of participants reported being involved in an ambulance crash within the past 12 months. When controlling for call volume and time in an ambulance, the odds of involvement in an ambulance crash within the past year were significantly higher for younger EMS professionals and those reporting sleep problems.Conclusions:Results from this analysis suggest age and sleep problems are associated with involvement in an ambulance crash. Future studies should investigate interventions to minimize the effects of these associations.

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Esta investigación analiza factores sociales de riesgo y de protección para el consumo excesivo de alcohol a partir de los datos de la Encuesta Nacional sobre prevalencias de consumo de sustancias psicoactivas, en 2008, en la población de jóvenes argentinos de 16 a 24 años. Se realizó análisis bivariado y multivariado. Se observó como factores de riesgo: la edad de inicio (el menor edad tiene mayor riesgo), la región Pampeana, Noroeste y Noreste, el género masculino y el provenir de hogares con necesidades básicas insatisfechas. Entre los factores protectores identifica: inactividad, no haber tenido posibilidad de probar drogas ilícitas, no sentir deseos de probar drogas ilícitas, y no haber consumido: tabaco, tranquilizantes, cocaína y pasta base - alguna vez en la vida. Los resultados aportan información útil para la formulación de programas preventivos para la población adolescente y joven.

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Trypanosoma cruzi, widely distributed in Latin American countries, provokes Chagas disease, characterized by cardiomyopathy and mega-viscera. The drugs used currently for treatment of acute Chagas disease are highly toxic; the side-effects are undesirable and patients may abandon treatment. We have previously demonstrated that clomipramine (CLO) exerts trypanocidal effects upon epimastigotes and trypomastigotes in vitro with anticalmodulin activity. The present study analyses the effectiveness of CLO treatment in mice infected with a low number of T. cruzi, an animal model that reproduces acute, indeterminate and chronic phases of this trypanosomiasis. In this work, our results demonstrated that CLO 5 mg/kg daily for 30 days, or 2 doses of CLO 40 mg/kg given intraperitoneally at 1 h and 7 days after infection, was not toxic for the host, but was effective against the parasite in that parasitaemias became negative and only mild heart structural and electrocardiographic alterations were detected in the chronic phase in the group treated with CLO 5 mg/kg. In mice treated with CLO 40 mg/kg, none of these alterations was detected. Cardiac beta receptor density and affinity returned to normal in the chronic stage in both experimental groups. T. cruzi enzymes such as calmodulin and trypanothione reductase represent potential drug targets. It has been reported that both can be inhibited by CLO, a tricyclic drug used in clinical therapeutics. We have shown that CLO strongly decreased the mortality rate and electrocardiographic alterations; in addition cardiac beta receptor density and heart histology returned to, or close to, normality 135 days post infection. These results clearly demonstrated that CLO treatment modified significantly the natural evolution of T. cruzi infection.