Vertical transmission of Trypanosoma cruzi in the Province of Choapa, IV Region, Chile: Preliminary Report (2005-2008)

Congenital Chagas disease acquired special importance in Chile after the certification of the control of Triatoma infestans and transmission by blood donors affected with Trypanosoma cruzi. In order to establish adequate protocols for intervention and control in infected mother-neonate pairs in endemic zones of Chagas disease, we present partial results (2005-2008) of a pilot project which is being carried out in the Province of Choapa, IV Region, Chile, whose objectives are: determine the current prevalence of the disease in pregnant women, estimate the incidence of vertical transmission of T. cruzi to newborns, determine the lineages of the parasite present in mothers who do and do not transmit the disease, determine the prevalence of Chagas disease in maternal grandmothers of neonates and study placental histopathology. Preliminary results indicated that in this study period, 3.7 percent of the women who gave birth in the Province have Chagas disease and 2.5 percent of their newborns were infected. The most frequent T. cruzi genotypes found in mothers studied during pregnancy were TCI and TCIId, either alone or in mixed infections. A high percentage (74.3 percent) of the grandmothers studied was infected with the parasite. In 29 placentas from mothers with Chagas disease we observed edema, necrosis, fibrinoid deposits and slight lymphoplasmocyte infiltration. In three placentas we found erythroblastosis and in one of them amastigote forms of T. cruzi; this was one of the cases of congenital infection. The evaluation of the diagnostic and control protocols generated will allow us to determine if it has been possible to modify the natural history of vertical transmission of T. cruzi in Chile.

Estudio farmacogenómico en trastorno límite de personalidad / Borderline personality disorder: a pharmacogenomic study

Antecedentes: Las conductas agresivas e impulsivas han sido asociadas con disfunciones del sistema serotoninérgico central. Polimorfismos del transportador de serotonina, de la triptófano hidroxilasa (TPH1) y de los receptores serotoninérgicos 5HT1B y 5HT2C han sido vinculados a agresión e impulsividad. Varios estudios en depresión mayor han demostrado que el alelo corto (S) del promotor del gen transportador de serotonina se asocia a una peor respuesta a los inhibidores selectivos de la recapacitación de serotonina (ISNS). Material y métodos: En este estudio se investigó la asociación entre la respuesta de la impulsividad al tratamiento con fluoxetina y polimorfismos del transportador de serotonina, TPH1 y de los receptores 5HT1B y 5HT2C, en 49 pacientes con trastorno límite de personalidad. Resultados: Los pacientes con el genotipo L/L del promotor del gen transportador de serotonina, evaluados mediante la Overt Aggression Scale-Modified (OAS-M), tuvieron una respuesta a fluoxetina significativamente mejor que los portadores del alelo S. No se encontró asociación entre la respuesta a fluoxetina y los genotipos de TPH1 y de los receptores 5HT1B y 5HT2C. Conclusiones: Este es el primer estudio en el que se evalúa la asociación entre estos polimorfismos y la respuesta anti-impulsiva a la fluoxetina en pacientes con trastorno límite de personalidad. El alelo S puede representar un factor común de peor respuesta a los ISRS en enfermedades asociadas a una disfunción serotoninérgica.

Background: Disturbances in central serotonin function have been implicated in impulsive and aggressive behavior. Serotonin transporter tryptophan hydroxylase (TPH1) and serotoninergic receptor (5HT1B, 5HT2C) polymorphisms have been linked to aggression and impulsivity. Several studies of major depression have shown that the short allele (S) of the serotonin transporter promoter gene is associated with a worse response to selective serotonin reuptake inhibitors (SSRIs). Material and methods: This study investigates the association between the response of impulsivity to fluoxetine treatment and serotonin transporter, TPH1 and 5HT1B and 5HT2C receptor polymorphisms in 49 patients with borderline personality disorder. Results: Patients with the Long/Long (L/L) genotype of the serotonin transporter promoter had a significantly better response to fluoxetine when compared to the S allele carriers, as evaluated by the Overt Aggression Scale-Modified (OAS-M). There were no significant associations between these polymorphisms and anti-impulsive response to fluoxetine in patients with borderline personality disorder. The S allele may represent a common factor of worse response to SSRIs in diseases associated to serotonin dysfunction.

DNA evidence of Trypanosoma cruzi in the Chilean wild vector Mepraia spinolai (Hemiptera: Reduviidae)

Molecular evidence showed 46.2 percent of Trypanosoma cruzi infection in Mepraia spinolai insects from North-Central Chile, which is significantly higher than previous reports of up to 26 percent by microscopic observation. Our results show similar infection levels among nymphal stages, ranging from 38.3 to 54.1 percent, indicating that younger nymphs could be as important as older ones in parasite transmission. A cautionary note must be stressed to indicate the potential role of M. spinolai in transmitting T. cruzi in country areas due to the high infection level detected by molecular analysis.

Studies on parasitemia courses and mortality in mice infected with genetically distant Trypanosoma cruzi clonets

The biological characterization of bloodstream forms of eleven Trypanosoma cruzi cloned stocks, corresponding to two genetically similar clonets (19 and 20) and one distant clonet (39), according to multilocus enzyme electrophoresis analysis, showed dissimilar parasitemia in an experimental isogenic mouse model. While clonet 39 stocks gave low parasitemias, clonets 19 or 20 stocks gave high parasitemias, independently of the inocula (102 and 104 bloodstream forms) used. High parasitemia did not always associate with greater mortality. Statistical studies on mortality using a low inocula showed significantly higher mortality with clonet 39 stocks when compared to clonets 19 or 20 stocks. Finally, in order to confirm the identity of each stock studied, typing by molecular karyotype was performed before inoculating mice.

Estandarización de la reacción de polimerización en cadena en muestras de sangre de ratones infectados con Trypasonoma cruzi / Standarization of the polymerase chain reaction in blood samples of mice infected with Trypasonoma cruzi

Se estandarizó la reacción de polimerización en cadena (PCR) para el diagnóstico parasitológico de la enfermedad de Chagas. Se determinó condiciones de estandarización de DNA, así como las concentraciones óptimas de dNTPs, partidores, Taq DNA polimerasa y las condiciones de termociclación. Se determinó que el ensayo es capaz de amplificar hasta 100 fg de DNa templado de trypasonoma cruzi, con una sensibilidad diagnóstica de 2x10² parásitos/ml. Los productos de PCR amplificados demostraron ser específicos mediante ensayos de hibridación con una sonda de DNA kinetoplastídico de T. cruzi