CO2 Enrichment Stimulates Dissolved Organic Carbon Release in Coral Reef Macroalgae.

Dissolved organic carbon (DOC) released by macroalgae is important in the context of coral reef degradation as it contributes to coral mortality by promoting bacterial metabolism on the coral surface. Using experimental carbon dioxide (CO2 ) manipulations in outdoor flow-through tanks, we found that seawater CO2 enrichment enhances daily net DOC release in a range of macroalgal species in the Great Barrier Reef (Australia). There was, however, large variability in DOC release among species, light and dark conditions, and CO2 exposure times. Under light conditions, DOC release in the red macroalga Amansia was 15 times higher under high CO2 conditions compared to ambient CO2 , however, CO2 enhancement did not affect DOC production in the other species. Results from the night incubations were more consistent as three of the four species (Amansia, Lobophora, and Sargassum) enhanced DOC release when enriched with CO2 . DOC fluxes shifted from production in the 1-d incubations to consumption in the 19-d experiment under light conditions, suggesting an important role of bacteria in DOC balances. The results suggest that rising CO2 (and ocean acidification) will continue to intensify space competition in favor of the macroalgae, potentially exacerbating reef degradation and ecological phase shifts from coral to macroalgal dominance.

Eficacia del destechado del túnel en infección crónica del catéter peritoneal / Tunnel unroofing effectiveness in chronic peritoneal catheter infection

Introducción: la infección crónica del catéter involucra generalmente la colonización del manguito de dacrón (ôcuffõ) externo; sin su remoción el tratamiento antibiótico es inefectivo, la técnica de destechado de catéter ha sido descrita como una alternativa a la extracción del catéter peritoneal. Material y métodos: Se analizaron datos en forma retrospectiva de 13 pacientes. Se evaluó la evolución luego del destechado, considerando como fracaso del tratamiento a la aparición de nueva infección en el orificio, túnel o peritonitis asociada al mismo germen. Resultados: Entre los años 1997-2014, se le practicó destechado a 13 pacientes. Edad promedio 46,23 años (IC 95%: 35,92 años û 56,54 años). Sexo masculino 9, 69,23% (IC 95%: 41,95% û 96,50%).Gérmenes estafilococo 7, pseudomona 2, polimicrobiano 1, cultivo negativo 3. Hubo curación en 9 pacientes, 69,23% (IC 95%: 41,95% û 96,06) no hubo asociación estadística entre sexo, edad, resultado microbiológico, presencia de hemodiálisis previa, tipo de catéter, técnica quirúrgica ni con el cirujano que realizó el procedimiento (p> 0.05). Discusión: La extracción del catéter implica la transferencia transitoria a hemodiálisis y una nueva cirugía de recolocación, si bien existe poca experiencia con la técnica de destechado, puede ser una alternativa válida, permitiendo a un grupo de pacientes continuar con el tratamiento de DP. Conclusión: La cirugía de destechado ha resultado beneficiosa en el 69,23% de los casos (9 pacientes) independientemente del tipo de germen presente, representando un tratamiento aceptable que evita la remoción del catéter permitiendo así la continuidad de la modalidad, disminuyendo la necesidad de emplear terapias más agresivas.

Introduction: chronic catheter infection usually involves external Dacron cuff colonization, without its removal, antibiotic treatment proved ineffective. Catheter unroofing technique has been described as an alternative to peritoneal catheter removal. Material and methods: We analyzed the data from 13 patients retrospectively. Evolution after unroofing was evaluated, considering as treatment failure the appearance of new infection in the hole, tunnel or peritonitis associated to the same germ. Results: Between 1997-2014 years, unroofing was performed on 13 patients. Mean age-rate: 46.2 (IC 95%: 35.9 years û 56.5 years) male sex 9, 69.23%. Germs: staphylococcus 7, pseudomona 2, polymicrobial 1, negative culture 3. Nine patiens healed: 69.2%; there was no statistical association among sex, age, microbiological result, previous hemodialysis use, type of catheter, surgical technique or with the surgeon who performed the procedure (p> 0.05). Discussion: Catheter removal implies transient transference to hemodialysis and new replacement surgery, although there is few experience with this technique, it could be an acceptable alternative, enabling a group of patients to continue with PD treatment. Conclusion: Unroofing technique proved to be beneficial in 69.2% of the cases (9 patients) independently of the type of germ present, representing an acceptable treatment which avoids catheter removal, enabling the procedure to continue, and decreasing the need to employ more aggressive therapies.