RESUMEN
Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.
Asunto(s)
Dióxido de Carbono/análisis , Secuestro de Carbono , Sedimentos Geológicos/química , Biomasa , Isótopos de Carbono , Costa Rica , Sedimentos Geológicos/microbiología , HelioRESUMEN
The ELISA has been extensively evaluated as a serodiagnostic method for tuberculosis. However, there is scarce information about its application to cases that cannot be diagnosed by microscopic examination: those with closed lesions or undergoing early stages of the disease. Since a reliable serological test might substantially contribute to their prompt detection, the objective of the present study was to determine the diagnostic value of an ELISA applied to adult smear-negative cases of tuberculosis. Sera from 235 patients with active tuberculosis--176 pulmonary and 59 extrapulmonary cases--and 181 control subjects were tested for IgG antibodies to PPD by ELISA. Eleven cases of non tuberculous mycobacterial (MOTT) disease and 33 cases of mycosis were also included in this group. With the adopted cut-off value, 73.9% (105/142) of smear positive and 52.7% (49/93) of smear negative tuberculosis cases, were correctly classified. Particularly in the latter, the test was positive in 55.2% (32/58) of patients with positive cultures for Mycobacterium tuberculosis and in 48.6% (17/35) of patients diagnosed by clinical, radiological and or histopathological findings. No antibody activity was demonstrated in 92.7% of sera from the control population which included 92 healthy volunteers, 32 non tuberculous diseased subjects and 13 household contacts of smear-positive cases. Among those control subjects who were skin tested, ELISA results were not related to the tuberculin reactivity: 93.7% (30/32) of tuberculin negative and 95.2% (40/42) of tuberculin positive healthy individuals had no detectable antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Técnicas para Inmunoenzimas , Tuberculosis/diagnóstico , Adulto , Estudios de Evaluación como Asunto , Humanos , Inmunoglobulina G/análisis , Mycobacterium tuberculosis/inmunología , Pruebas SerológicasRESUMEN
Se evaluó un enzimoinmunoensayo (EIE) para la detección de anticuerpos IgG circulantes anti-PPD en el diagnóstico de la tuberculosis paucibacilar del adulto. El 73,9% de 142 pacientes bacilíferos y el 52,7% de 93 casos con baciloscopia negativa resultaron seropositivos por EIE. Particularmente en este último grupo la prueba fue positiva en el 55,25 de 58 pacientes diagnosticados por cultivo y en el 48,6% de 35 pacientes con diagnóstico clínico-radiológico de tuberculosis. El 92,7% de 137 sueros de la población control carecia de anticuerpos detectables. En los sujetos sanos que fueron tuberculinizados los resultados del EIE no se realacionaron con la respuesta tuberculínica: el 93.7% (30/32) de los tuberuclino negativos y el 95,2% (40/42) de los reactores a la tuberculina fueron negativos por EIE. Trece de 33 casos de PPD. Ciertamente el EIE tuvo máxima sensibilidad en la detección de casos bacilíferos, no obstante permitió identificar también a más de la mitad de los pacientes con baciloscopia negativa. Por lo tanto, puede ser considerado um método útil para el diagnóstico presuntivo rápido de la tuberculosis paucibacilar, excepto en los casos en los que se plantee el diagnóstico diferencial con micosis o con otras micobacterosis (AU)
Asunto(s)
Humanos , Adulto , Tuberculosis/diagnóstico , Técnicas para Inmunoenzimas , Inmunoglobulina G/análisis , Estudio de Evaluación , Mycobacterium tuberculosis/inmunologíaRESUMEN
Se evaluó un enzimoinmunoensayo (EIE) para la detección de anticuerpos IgG circulantes anti-PPD en el diagnóstico de la tuberculosis paucibacilar del adulto. El 73,9% de 142 pacientes bacilíferos y el 52,7% de 93 casos con baciloscopia negativa resultaron seropositivos por EIE. Particularmente en este último grupo la prueba fue positiva en el 55,25 de 58 pacientes diagnosticados por cultivo y en el 48,6% de 35 pacientes con diagnóstico clínico-radiológico de tuberculosis. El 92,7% de 137 sueros de la población control carecia de anticuerpos detectables. En los sujetos sanos que fueron tuberculinizados los resultados del EIE no se realacionaron con la respuesta tuberculínica: el 93.7% (30/32) de los tuberuclino negativos y el 95,2% (40/42) de los reactores a la tuberculina fueron negativos por EIE. Trece de 33 casos de PPD. Ciertamente el EIE tuvo máxima sensibilidad en la detección de casos bacilíferos, no obstante permitió identificar también a más de la mitad de los pacientes con baciloscopia negativa. Por lo tanto, puede ser considerado um método útil para el diagnóstico presuntivo rápido de la tuberculosis paucibacilar, excepto en los casos en los que se plantee el diagnóstico diferencial con micosis o con otras micobacterosis
Asunto(s)
Humanos , Adulto , Técnicas para Inmunoenzimas , Tuberculosis/diagnóstico , Estudio de Evaluación , Inmunoglobulina G/análisis , Mycobacterium tuberculosis/inmunologíaRESUMEN
The ELISA has been extensively evaluated as a serodiagnostic method for tuberculosis. However, there is scarce information about its application to cases that cannot be diagnosed by microscopic examination: those with closed lesions or undergoing early stages of the disease. Since a reliable serological test might substantially contribute to their prompt detection, the objective of the present study was to determine the diagnostic value of an ELISA applied to adult smear-negative cases of tuberculosis. Sera from 235 patients with active tuberculosis--176 pulmonary and 59 extrapulmonary cases--and 181 control subjects were tested for IgG antibodies to PPD by ELISA. Eleven cases of non tuberculous mycobacterial (MOTT) disease and 33 cases of mycosis were also included in this group. With the adopted cut-off value, 73.9
(105/142) of smear positive and 52.7
(49/93) of smear negative tuberculosis cases, were correctly classified. Particularly in the latter, the test was positive in 55.2
(32/58) of patients with positive cultures for Mycobacterium tuberculosis and in 48.6
(17/35) of patients diagnosed by clinical, radiological and or histopathological findings. No antibody activity was demonstrated in 92.7
of sera from the control population which included 92 healthy volunteers, 32 non tuberculous diseased subjects and 13 household contacts of smear-positive cases. Among those control subjects who were skin tested, ELISA results were not related to the tuberculin reactivity: 93.7
(30/32) of tuberculin negative and 95.2
(40/42) of tuberculin positive healthy individuals had no detectable antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)