Congenital co-infection with different Trypanosoma cruzi lineages.

Variability of mixed Trypanosoma cruzi congenital infection in Chile in twenty one congenital samples of Chagas disease is reported. Recognition of infecting strains was performed by minicircle hybridization tests. Seven newborns with double infection were found. Trypanosoma cruzi TcII and TcV lineages were the most frequent in single and mixed infections. With these results we pretend to understand the epidemiological significance of the T. cruzi lineages for which the placenta does not seem to represent an actual barrier in congenital infections.

Infección materna y transmisión transplacentaria del Trypanosoma cruzi en Chile: diagnóstico, tratamiento y control / Trypanosoma cruzi transplacental infection in Chile: diagnosis, treatment and control

Trypanosoma cruzi transplacental infection represents a serious public health concern in all the countries like Chile where recent success of insecticide spraying programs eliminated the vector. Because children infected with T. cruzi are usually asymptomatic, a study was designed including infected mothers and their children. The study was conducted for three years to establish diagnostic, treatment, and clinical observations variables. Mothers were tested for T. cruzi IgG, and the new born were examined for parasite DNA using PCR amplification. They were treated with nifurtimox and it was 100% effective, confirmed by successive PCR tests. It has been determined that there are 800 to 1000 new cases a year of transplacental Chagas' disease in Chile. This level of infection in the population should justify the establishment of a control and follow-up program for transplacental Chagas' disease.

Okadaic acid-sensitive activation of Maxi Cl(-) channels by triphenylethylene antioestrogens in C1300 mouse neuroblastoma cells.

1. The regulation of Maxi Cl(-) channels by 17beta-oestradiol and non-steroidal triphenylethylene antioestrogens represents a rapid, non-classical effect of these compounds. In the present study we have investigated the signalling pathways used for the regulation of Maxi Cl(-) channel activity by oestrogens and antioestrogens in C1300 neuroblastoma cells. 2. Whole-cell Maxi Cl(-) currents were readily and reversibly activated by tamoxifen, toremifene and the membrane-impermeant ethyl-bromide tamoxifen, only when applied to the extracellular medium. 3. Pre-treatment of C1300 cells with oestrogen or cAMP prevented the antioestrogen-induced activation of Maxi Cl(-) channels. The inhibitory effect of 17beta-oestradiol and cAMP was abolished by the kinase inhibitor staurosporine. 4. Current activation was unaffected by the removal of intracellular Ca(2+) and Mg(2+), but was completely abolished in the presence of okadaic acid. These results are consistent with the participation of an okadaic acid-sensitive serine/threonine protein phosphatase in the activation of Maxi Cl(-) channels. However, neither oestrogen or antioestrogen treatment modified the total activity of the two major serine/threonine phosphatases, PP1 and PP2A, in C1300 cells. 5. Although the role of these Maxi Cl(-) channels remains unknown, our findings suggest strongly that their modulation by oestrogens and antioestrogens is linked to intracellular signalling pathways.

[Serological certification of the interruption of the vectorial transmission of Chagas disease in Chile]. / Certificación serológica de la interrupción de la transmisión vectorial de la enfermedad de Chagas en Chile.

BACKGROUND: In 1999 an International Commission of Experts evaluated the sanitary interventions that started in 1980 to eliminate Triatoma infestans, the biological vector of Chagas disease, to certify if the conditions needed to interrupt the transmission, were achieved. AIM: To report the data used by the International certification commission to certify the interruption of vectorial transmission of Chagas disease in Chile. MATERIAL AND METHODS: A comparative evaluation of the prevalence of Trypanosoma cruzi antibodies in children surveyed between 1994 and 1995 and between 1995 and 1999. RESULTS: In the first period, 5,948 children were surveyed and in the second, 5,069 children were studied. Twenty children (0.4%) were positive for Trypanosoma cruzi antibodies in the second survey. These figures were significantly lower than the 1.1% prevalence detected between 1994 and 1995. In only three of the 20 cases, the transmission through vectors was confirmed, which represents a 99.4% reduction of this way of transmission. CONCLUSIONS: Based on these findings, the Commission certified that Chile is the second country in Latin America to interrupt the vector transmission of Chagas disease. The successful public health program for Chagas disease will have a positive impact improving the quality of life of rural populations, that are most exposed to the disease.

[Epidemiological status of Chagas disease in the endemic area from Region II of Antofagasta]. / Situación epidemiológica de la enfermedad de Chagas en el área endémica de la II Región de Antofagasta, Chile.

During 1997 a seroepidemiological study on Chagas' disease was carried out in 18 localities of three provinces (Tocopilla, El Loa and Antofagasta) of Region II (20 degrees 56'-26 degrees South Lat.; 70 degrees 38'-67 degrees West Long.), in order to assess the impact of the control program against Triatoma infestans launched in 1988, based on insecticide spraying of dwellings. By means of ELISA and an indirect hemagglutination test for Chagas' disease blood samples from 1,034 children under 10 years of age were examined, arising a 0.5% (3 cases) positivity. Test resulted positive in 2 (0.9%) children from the locality of San Pedro de Atacama and 1 (0.4%) from Calama city, all in the age group 6-10 year-old. However, none of their dwellings were found infested with T. infestants. These results indicate that the control program has a good possibility to prevent new human infections. It is advisable to continue the seroepidemiological and entomological vigilance and remark the necessity of increasing the effort in the study of transmission through other routes, to adopt or reinforce the pertinent preventive measures.

Acute activation of Maxi-K channels (hSlo) by estradiol binding to the beta subunit.

Maxi-K channels consist of a pore-forming alpha subunit and a regulatory beta subunit, which confers the channel with a higher Ca(2+) sensitivity. Estradiol bound to the beta subunit and activated the Maxi-K channel (hSlo) only when both alpha and beta subunits were present. This activation was independent of the generation of intracellular signals and could be triggered by estradiol conjugated to a membrane-impenetrable carrier protein. This study documents the direct interaction of a hormone with a voltage-gated channel subunit and provides the molecular mechanism for the modulation of vascular smooth muscle Maxi-K channels by estrogens.

[Evaluation of a triatoma infestans eradication program in rural dwellings from the IV region, Chile, by means of serology for Chagas disease in 0-10 years old children]. / Evaluación de un programa de erradicación del Triatoma infestans en viviendas rurales de la IV región, Chile, mediante serología para la enfermedad de Chagas en niños de 0-10 años de edad.

The present study deals with the evaluation of the effectiveness of the measures employed in the control of Triatoma infestans, the vector of Trypanosoma cruzi infection (Chagas' disease), in the IV region of Chile through a serological follow up program. For this reason, a serological survey has been carried out in 2,783 children, from 0 to 10 years, who live in rural high endemic areas of the region. The sera were tested using an indirect hemagglutination test (IHAT) and ELISA techniques with results agreeing in 99.9% of the samples. In children with positive serology xenodiagnosis was performed and blood samples from the corresponding mothers were submitted to serology for Chagas' disease. These additional tests should allow to distinguish between congenital infection and vectorial transmission. It was observed that vectorial transmission of T. cruzi was interrupted in some localities where entomological control has been applied for 10 years, or lowered in those which have been submitted to desinsectations in the last 5 years. On the other hand, a relatively high prevalence of the infection has been detected in some localities. These results suggest an apparent increase of vectorial transmission, indicating the need of readjusting the dwellings insecticide sprayings activities to improve the measures against the vector.

Diagnostic value of detecting specific IgA and IgM with recombinant Trypanosoma cruzi antigens in congenital Chagas' disease.

The present study compares the early diagnosis of congenital Chagas' disease with a DOT assay using recombinant antigens with immunofluorescence antibody testing (IFAT) and an enzyme-linked immunosorbent assay (ELISA). The studies were performed using cord blood and sera of 12 infected newborns (group I) and 12 uninfected ones born to Trypanosoma cruzi-infected mothers (group II). Conventional IFAT and ELISA showed positive results for IgG at high titers, in infants and mothers of both groups; IgA antibodies were detected by ELISA in four of the infected infants and IgM was detected in two of them. All sera of the uninfected infants were negative for IgA and IgM in the ELISA. Application of a DOT assay using eight recombinant T. cruzi antigens allowed detection of specific IgA in the cord blood of six of the infected cases and IgM in eight of them. Repetition of these serologic tests in samples obtained during a monthly follow-up gave positive results for IgA in two of the initially negative infants of group I and for IgM in four of them. This means that diagnosis of congenital T. cruzi infection was confirmed, through demonstration of specific IgM, in all infected infants, and of IgA in eight of them. The importance of late detection of IgM in siblings born of infected mothers is discussed. The detection of IgM and IgA in sera obtained after birth is believed to be due to a congenital transmission of the parasite that occurred late in pregnancy. No IgA or IgM antibodies could be detected by the DOT assay in the sera of the negative controls.(ABSTRACT TRUNCATED AT 250 WORDS)

[A survey of the depressive symptoms in pregnant women at an urban primary care consultation office]. / Encuesta sobre síntomas de depresión en embarazadas de un consultorio urbano de atención primaria.

We studied the frequency of depression as well as biomedical and social features of 179 pregnant women under control at an urban clinic in metropolitan Santiago. The random sample comprised 38% of all controlled pregnancies. A questionnaire adapted and validated by Florenzano et al was used to appraise depression. The Graffar methodology was used to measure socioeconomic level. Frequency of depressive symptoms was 30% and mean age of depressed women was 27.3 years, similar to non depressed ones (26.1%). A significantly higher proportion of depression was found in single women and those having a dystocic last delivery. The high frequency of depression in this vulnerable group suggests the need for integrated obstetric-psychiatric units to provide a more comprehensive medical care to theses patients.