Caracterización fisonómico-estructural del “Bosque Encantado” (General Belgrano; provincia de Buenos Aires): una experiencia en extensión de la Cátedra de Ecología de Comunidades y Sistemas

En este trabajo compartimos nuestra experiencia como docentes de la Cátedra de Ecología de Comunidades y Sistemas (FCNyM-UNLP) en la realización junto a los alumnos del ciclo lectivo 2005, de una caracterización fisonómico-estructural del “Bosque Encantado” (Gral. Belgrano; Bs. As.). La misma fue anexada al anteproyecto de ley como sustento académico para declararlo Paisaje Protegido de Interés Provincial para su conservación (de acuerdo a la Ley 12.704), como patrimonio biológico y paisajístico. La actividad tuvo tres ejes centrales: 1) Aplicar conocimientos teóricos y aplicados adquiridos en la asignatura, 2) Integrar conceptos tratados en otros cursos de la carrera, y 3) Obtener práctica del ejercicio profesional del biólogo en la toma de decisiones sobre la creación de áreas protegidas y el asesoramiento del uso de los recursos naturales y el medioambiente.Facultad de Ciencias Naturales y Muse

Concentración de pesticidas organoclorados en aire del sur de la cuenca del Plata: un año de muestreo

<p>Con el objeto de estudiar la concentración y distribución de plaguicidas organoclorados (POCLs) en aire del sur de la cuenca del Plata se instalaron muestreadores pasivos de espuma de poliuretano (n=20) recolectados cada 3-4 meses durante un año.</p><p>La concentración media anual de POCLs osciló entre 326 y 9000 pg/m³ con predominancia de endosulfanos (Endo)  (40-98% del total). Los promedios anuales de Endo (230-8936 pg/m³)  son superiors a los reportados para otros paises de la región  (Brasil, Bolivia, Chile y Colombia: 114-898 pg/m³. Los valores máximos alcanzados corresponden al período cálido, en zonas de mayor actividad sojera: Norte de Bs As y Sur de E.Ríos y Santa Fe (3072-21521 pg/m³).</p><p>Las concentraciones de DDTs (12-235 pg/m³) resultan un orden de magnitud inferiores a las de sitios en los que se utiliza para combatir la malaria (India: 5356 pg/m³; sur de México: 2360 pg/m³) pero la relación DDT/DDE (1.1-6.8) &gt; 1 encontrada sugiere un aporte relativamente fresco, posiblemente debido al uso de Dicofol que presenta residuos de este compuesto.</p><p>Los HCHs presentaron una alta concentración en Zárate (801-8348 pg/m³) donde resultaron predominantes (66% del total) con una relación ?/?HCHs ?7, similar a la de la mezcla técnica sugiriendo un aporte fresco.</p><p>En la zona metropolitana se destacaron los clordanos (83-691 pg/m³) que representan 5-45% del total, especialmente en la Capital Federal, donde la relación trans/cis-clordano&gt;&gt;1,6 indica un aporte fresco.</p><p>Se concluye que los POCLs presentan diferencias en su distribución espacial; alta concentración de endosulfanos en zona agrícola; heterogeneidad de pesticidas  y mayor concentración de clordanos en zonas urbanas. Los valores de las concentraciones  y de relaciones entre compuestos sugieren aportes frescos clandestinos, o transporte a gran escala.</p

Comparative approach for trace metal risk evaluation in settling particles from the Uruguay River, Argentina: enrichment factors, sediment quality guidelines and metal speciation

The source and potential risks of trace metals in settling material collected with sediment traps in the Uruguay River were evaluated utilizing enrichment factors (EF), sediment quality guidelines (SQG) and speciation using a 4-step sequential extraction procedure. The total organic carbon content of the settling material was relatively high and homogeneous (2.5 ± 0.3 %) and showed no correlation with the metal concentrations. Total trace metal concentrations decrease from Fe (48,969 ± 7380 µg g−1), Mn (1859 ± 233 µg g−1), Zn (84 ± 7.6 µg g−1), Cu (56 ± 6.9 µg g−1), Cr (19 ± 2.7 µg g−1), Ni (16 ± 2.0 µg g−1) and Pb (13 ± 1.2 µg g−1). The average EF of Zn, Cr, Ni and Pb are below 1.5 indicating natural sources, whereas those of Cu and Mn are consistently higher (EF > 2) insinuating some anthropogenic influence. Consistently, Cu concentrations duplicated the SQG (35.7 μg g−1) suggesting that adverse biological effects may be observed occasionally. However, speciation results revealed that most metals are associated with the residual fraction, strongly linked to the mineral matrix, and therefore unavailable to aquatic organisms. The sole exception is Mn which is mainly found in the non-residual fractions (∑F1 − F3 = 82 %). Trace metal mobility/bioavailability decreased from Mn (82 %) ≫ Pb (37 %) > Cr (26 %) ~ Ni (25 %) > Zn (20 %) > Cu (14 %) > Fe (10 %). These results demonstrate the utility of metal speciation studies to assess the real risk for aquatic organisms of high Cu concentrations, but associated to relatively immobile fractions of reduced bioavailability.Fil: Tatone, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bilos, Claudio. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Skorupka, Carlos Norberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; ArgentinaFil: Colombo, J. C.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Química Ambiental y Biogeoquímica; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Vascular and metabolic effects of the haem oxygenase-1 inducer haem arginate in subjects with the metabolic syndrome : A translational cross-over study

This translational randomized and vehicle-controlled cross-over study was performed to assess the impact of haem arginate treatment on haem oxygenase-1 induction, endothelial function and insulin sensitivity in subjects with the metabolic syndrome (n = 14). Both treatment periods consisted of 5 days. Haem arginate or vehicle (l-arginine) was administered intravenously on Days 1 and 3. Forearm blood flow in response to acetylcholine and nitroglycerine was measured by venous occlusion plethysmography (Day 3), insulin sensitivity by a hyperinsulinaemic clamp procedure (Day 5). Haem arginate did not improve endothelial function or insulin sensitivity but significantly reduced the vasodilator response to nitroglycerine (p < 0.01). These negative findings are in contrast to the preclinical data, which may be due to short duration of therapy and limited haem oxygenase-1 induction as well as interference by markedly elevated plasma haem levels observed after haem arginate treatment (p < 0.01). Future studies should pay attention to the delicate balance between sufficient dosing and timely normalization of plasma haem levels

Nationwide Study on Treatment of Mycotic Thoracic Aortic Aneurysms

Objective/background: Mycotic aortic aneurysms are rare, life threatening, and complex. This nationwide study aimed to assess outcome after repair of mycotic thoracic aortic aneurysms (MTAAs). Methods: Patients treated in Sweden for MTAAs between 2000 and 2016 were identified in the Swedish vascular registry (2010–16) and local patient registries (2000–09). Primary outcome was survival, and secondary outcomes included surgical strategy, rate of infection related complications (IRC), and re-operations. Results: Fifty-two patients (median age 71 ± 8.1 years; 28 [54%] men, 13 [25%] ruptured) were identified (3.6% of all thoracic aortic aneurysm repairs in Sweden). Aneurysm location was aortic arch (n = 6; 11%), descending aorta (n = 42; 81%), and multiple locations (n = 4; 8%). Twenty-nine (56%) patients had positive cultures; the most prevalent agent was Staphylococcus aureus (n = 16; 31%). Operative techniques included thoracic endovascular aortic repair (TEVAR; n = 35 [67%]), fenestrated/branched TEVAR (n = 8; 15%), hybrid repair (n = 7; 14%), and open patch repair (n = 2; 4%). Survival was 92% (95% confidence interval [CI] 88–96) at 30 days, 88% (95% CI 84–93) at three months, 78% (73–84) at one year, and 71% (64–77) at five years. The mean follow up among survivors (> 90 days) was 45 months (range 4–216 months). Antibiotics were administered for a median of 15 weeks (range 0–220 weeks). IRCs occurred in nine patients (17%): sepsis (n = 3), graft infection (n = 3), recurrent mycotic aneurysm (n = 1), aorto-oesophageal/bronchial fistula (n = 2). Six (67%) IRCs were fatal; 80% occurred within the first year. Re-operations were performed in nine patients (17%). Conclusions: TEVAR was often used as treatment for MTAAs, with acceptable short- and long-term survival when compared with open cohorts in the literature. IRCs are of concern and warrant follow up and long-term antibiotic treatment