PCR-based diagnosis for Chagas' disease in bolivian children living in an active transmission area : comparison with conventional serological and parasitological diagnosis

A large field study has been performed in the Cochabamba region of Bolivia with the aim of comparing the polymerase chain reaction (PCR) with other diagnosis methods for Chagas' disease. The amplification of #Trypanosoma cruzi$-specific kinetoplast DNA sequences in blood samples was compared with classical serological methods, specific IgM detection and direct parasite visualization for 268 school children in a single village where Chagas' disease transmission is active. Of 113 children positive by classical serology or buffy coat examination, 106 were detected by PCR (sensitivity : 93,8%). We did not observe any significant difference of PCR sensitivity between initial (IgM and/or buffy coat positive) and indeterminate stage (only IgG positive) patients. Among the remaining 155 children unconfirmed as chagasic (who were either only IgM positive, or IgG-, IgM-, and buffy coat -negative) only one case was PCR positive. This case may be due to DNA contamination, or to a very recent infection not detected otherwise, or to specific immune depression. These results show that PCR is a very sensitive parasitological test for Chagas' disease in active transmission regions. The future follow-up of the possibly infected patients who were only IgM-positive should clarify the interest of PCR and IgM tests in the detection of starting infections. (Résumé d'auteur

Modulation of Cardiocyte Functional Activity by Antibodies against Trypanosoma cruzi Ribosomal P2 Protein C Terminus

Antibodies against the Trypanosoma cruzi ribosomal P2β protein (TcP2β) have been associated with the chronic cardiac pathology of Chagas' disease in humans. Using synthetic peptides spanning the entire TcP2β molecule, we investigated their epitope recognition by antibodies from mice chronically infected with T. cruzi and from mice immunized with two recombinant TcP2βs. We found clear differences in epitope recognition between antibodies from T. cruzi-infected mice and mice immunized with two different recombinant TcP2βs associated with different schedules of immunization. Major epitopes recognized by antibodies from mice immunized with recombinant glutathione S-transferase (GST) or histidine (Hist) fusion TcP2β (GST-TcP2β or Hist-TcP2β) are located in the central and hinge regions of the molecule. Nevertheless, mice immunized with Hist-TcP2β were also able to elicit antibodies against the TcP2β C terminus, a region which is highly conserved in both T. cruzi and mammal ribosomal P proteins. Strikingly, antibodies from infected animals recognized only the TcP2β C terminus. By using these antisera with distinct profiles of epitope recognition, it could be shown that only C terminus-specific antibodies were able to increase the beating frequency of cardiomyocytes from neonatal rats in vitro by selective stimulation of the β1-adrenergic receptor. Thus, antibodies against the TcP2β C terminus elicited in the absence of infection are able to modulate a functional activity of host cells through a molecular mimicry mechanism

Polycapillary lenses for soft x-ray transmission in ITER: Model, comparison with experiments, and potential application

Measuring Soft X-Ray (SXR) radiation [0.1 keV; 15 keV] in tokamaks is a standard way of extracting valuable information on the particle transport and magnetohydrodynamic activity. Generally, the analysis is performed with detectors positioned close to the plasma for a direct line of sight. A burning plasma, like the ITER deuterium-tritium phase, is too harsh an environment to permit the use of such detectors in close vicinity of the machine. We have thus investigated in this article the possibility of using polycapillary lenses in ITER to transport the SXR information several meters away from the plasma in the complex port-plug geometry

Pcr-based diagnosis for chagas disease in Bolivian children living in a active transmission area: comparison with conventional serological and parasitological diagnosis

Submitted by sandra infurna ([email protected]) on 2016-06-30T11:20:26Z No. of bitstreams: 1 carlos25_morel_etal_IOC_1997.pdf: 641756 bytes, checksum: a4bf37cc41aa08fdae72b8ff195633fe (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-06-30T11:39:05Z (GMT) No. of bitstreams: 1 carlos25_morel_etal_IOC_1997.pdf: 641756 bytes, checksum: a4bf37cc41aa08fdae72b8ff195633fe (MD5)Made available in DSpace on 2016-06-30T11:39:05Z (GMT). No. of bitstreams: 1 carlos25_morel_etal_IOC_1997.pdf: 641756 bytes, checksum: a4bf37cc41aa08fdae72b8ff195633fe (MD5) Previous issue date: 1997Submitted by Angelo Silva ([email protected]) on 2016-07-07T11:16:54Z No. of bitstreams: 3 carlos25_morel_etal_IOC_1997.pdf.txt: 7 bytes, checksum: 212b0306580d4f0044d18f9a3edcc832 (MD5) carlos25_morel_etal_IOC_1997.pdf: 641756 bytes, checksum: a4bf37cc41aa08fdae72b8ff195633fe (MD5) license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-07-07T12:22:10Z (GMT) No. of bitstreams: 3 license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) carlos25_morel_etal_IOC_1997.pdf: 641756 bytes, checksum: a4bf37cc41aa08fdae72b8ff195633fe (MD5) carlos25_morel_etal_IOC_1997.pdf.txt: 7 bytes, checksum: 212b0306580d4f0044d18f9a3edcc832 (MD5)Made available in DSpace on 2016-07-07T12:22:10Z (GMT). No. of bitstreams: 3 license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) carlos25_morel_etal_IOC_1997.pdf: 641756 bytes, checksum: a4bf37cc41aa08fdae72b8ff195633fe (MD5) carlos25_morel_etal_IOC_1997.pdf.txt: 7 bytes, checksum: 212b0306580d4f0044d18f9a3edcc832 (MD5) Previous issue date: 1997Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Laboratório de Biologia Molecular e Doenças Endêmicas. Rio de Janeiro, RJ, Brasil / Faculté de Medicine. Laboratoire Génome des Parasites, Parasitologie. Montpellier, France.UR41, UMR ORSTOM/CNRS 9926 "Génetique moléculaire des Parasites et des Vecteurs". La Paz, Bolivia.UR41, UMR ORSTOM/CNRS 9926 "Génetique moléculaire des Parasites et des Vecteurs". La Paz, Bolivia.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Laboratório de Biologia Molecular e Doenças Endêmicas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Laboratório de Biologia Molecular e Doenças Endêmicas. Rio de Janeiro, RJ, Brasil.Universidad Mayor de San Andres. IBBA. La Paz, Bolivia.Institut Pasteur, Départment d`Immunologie et Centre de Biologie Médicale. Paris, France.Institut Pasteur, Départment d`Immunologie et Centre de Biologie Médicale. Paris, France.UR41 ORSTOM. La Paz, Bolivia.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Laboratório de Biologia Molecular e Doenças Endêmicas. Rio de Janeiro, RJ, Brasil.UR41, UMR ORSTOM/CNRS 9926 "Génetique moléculaire des Parasites et des Vecteurs". La Paz, Bolivia.A large field study has been performed in the Cochabamba region of Bolivia with the aim of comparing the polymerase chain reaction (PCR) with other diagnostic methods for Chagas' disease. The amplification of Trypanosoma cruzi-specific kinetoplast DNA sequences in blood samples was compared with classical serological methods, specific IgM detection and direct parasite visualization for 268 school children in a single village where Chagas' disease transmission is active. Of 113 children positive by classical serology or buffy coat examination, 106 were detected by PCR (sensitivity: 93.8%). We did not observe any significant difference of PCR sensitivity between initial (IgM and/or buffy coat positive) and indeterminate stage (only IgG positive) patients. Among the remaining 155 children unconfirmed as chagasic (who were either only IgM positive, IgG-, IgM-, and buffy coat-negative) only 1 case was PCR positive. This case may be due to DNA contamination, or to a very recent infection not detected otherwise, or to specific immune depression. These results show that PCR is a very sensitive parasitological test for Chagas' disease in active transmission regions. The future follow-up of the possibly infected patients who were only IgM-positive should clarify the interest of PCR and IgM tests in the detection of starting infections