Toxinas Algales en el Mar Argentino: nuevos hallazgos, nuevos desafíos / Algal Toxins in the Argentine Sea: new findings, new challenges

Resumen Las floraciones de algas nocivas son un problema cada vez más frecuente a nivel mundial que ocasiona severos daños sobre la salud pública, pérdidas económicas en acuicultura, perjuicios al turismo y episodios de mortalidad de poblaciones naturales de peces, aves y mamíferos marinos. Las toxinas son producidas por el fitoplancton y se acumulan en moluscos bivalvos que se alimentan por filtración del agua siendo estos los principales vectores de intoxicación humana. En el Mar Argentino, se han reportado toxinas marinas de origen microalgal asociadas con cuatro síndromes de intoxicación por moluscos. Los síndromes más graves por su extensión, frecuencia, toxicidad y organismos afectados, son los originados por el dinoflagelado Alexandrium cate-nella responsable de la Intoxicación Paralizante por Moluscos la cual ha ocasionado numerosas muertes humanas. Seguidamente, la más leve, en cuanto a gravedad y frecuencia, ha sido la Intoxicación Diarreica por Moluscos. En contraste, el ácido domoico, conocido como toxina amnésica de moluscos, no ha producido hasta ahora intoxicaciones humanas. Recientemente, se amplió el rango de toxinas para la región al registrarse las toxinas y los dinoflagelados productores de la Intoxicación Azaspirácidos por Moluscos. Además, se han detectado las potencialmente tóxicas Yessotoxinas y Espirolidos, cuyos mecanismos de acción y toxicidad están siendo aún evaluados a nivel mundial. Estas toxinas emergentes para la región, representan un riesgo potencial para la salud e inconvenientes socioeconómicos por el cierre de los sitios de explotación de moluscos. Ciertamente presentan un nuevo desafío, pues la detección y cuantificación sólo puede realizarse por medio de métodos basados en HPLC - espectrometría de masas, lo cual dificulta el monitoreo en laboratorios regionales en el país. La herramienta clave de manejo es la prevención, a través de políticas, regulaciones y sistemas de monitoreo y control de cada grupo de toxinas. A través de estas mejoras, se anticipa que no sólo disminuirá el número de afectados por estas intoxicaciones, si no que se podrán realizar vedas más eficientes, asegurando un equilibrio que proteja tanto la salud pública como el desarrollo de la industria pesquera.

Abstract Harmful algal blooms are an increasingly common problem worldwide, causing severe damage to public health, economic losses in aquaculture, damage to tourism and mortality events of natural populations of fish, birds and marine mammals. The toxins are produced by phytoplankton and accumulated in bivalve molluscs that feed on water filtration, being these main vectors of human intoxication. In the Argentine Sea marine toxins of microalgal origin have been reported associated with four shellfish poisoning syn-dromes. The most serious due to their extension, frequency, toxicity and affected organisms are those caused by the dinoflagellate Alexandrium catenella responsible for the Paralytic shellfish poisoning that has caused numerous human deaths. Then, the mildest, in severity and frequency, is the Diarrhetic shellfish poisoning. In contrast, domoic acid, known as Amnesic shellfish toxin, has not produced human intoxications yet. Recently, toxins and dinoflagellate species causing Azaspiracid shellfish poisoning have been re-corded, expanding the range of toxins for the region. In addition, the potentially toxic Yessotoxins and Spirolides have been detected, whose mechanism of action and toxicity is still being evaluated worldwide. These emerging toxins represent a potential risk to public health and socioeconomic activities due to the eventual closure of mollusc exploitation sites. They certainly present a new challenge, since detection and quantification can only be carried out using methods based on HPLC - mass spectrometry, which makes monitor-ing in regional laboratories difficult. Prevention through policies, regulations, and monitoring and control systems of each toxin group is the key management tool. These preventive measures are expected to contribute to reducing the number of poisonings and to ap-plying more efficient fisheries closures, ensuring a balance that protects both public health and the development of the fishing industry.

Experimental exposure of the mussel Mytilus platensis (d'Orbigny, 1842) to the dinoflagellate Alexandrium catenella from Argentine Patagonia.

Individuals of Mytilus platensis were exposed to Alexandrium catenella to evaluate the accumulation and metabolization of paralytic shellfish toxins (PST) over a period of 25 days. Mussels were collected from the intertidal zone of Cerro Avanzado, Argentine Patagonia. After 16 days, the toxins in the tissues of mussels were detected by the methods of mouse bioassay and high performance liquid chromatography with fluorometric detection (HPLC-FDL). The accumulation kinetics of PST toxins in M. platensis fed with A. catenella fitted to a linear function, in which the accumulation rate was 31.2 µg STX eq kg-1 day-1. After 16 days, the PST toxin level in tissues of mussels reached 1178 µg STX eq kg-1 exceeding the safety limit for human consumption (800 µg STX eq kg-1 tissue), whereas the highest PST toxin level was reached at the end of the experimentation (1613 µg STX eq kg-1) at 25 days. Differences in the toxin profile of the dinoflagellates and the tissues of the mussels confirmed biotransformation of PST in the mussel digestive system. The toxin profile of M. platensis was dominated by the gonyautoxins GTX1 and GTX4, while the toxin profile of A. catenella was dominated by the N-sulfocarbamoyl toxin C2. To our knowledge, this is the first experimentation on a laboratory scale of PST toxins accumulation in M. platensis with a native strain of A. catenella of Argentine Patagonia.

Harmful phytoplankton in the Beagle Channel (South America) as a potential threat to aquaculture activities.

The Beagle Channel is a remote subantarctic environment where mussel aquaculture initiatives have existed since the early 1990s. Here we analyze phytoplankton biomass and composition, and the occurrence of harmful microalgae species and their toxins at three sites during the period 2015-2016. The occurrence of potentially harmful algae was observed throughout the study period, including toxigenic dinoflagellates such as Alexandrium catenella (Group I of the A. tamarense complex), A. ostenfeldii, Dinophysis acuminata, Gonyaulax spinifera, Azadinium sp., and the diatoms Pseudo-nitzschia australis and P. fraudulenta. Toxic dinoflagellates were detected in low densities whereas a Pseudo-nitzschia bloom was observed in late February. Isolates of A. catenella and P. delicatissima sensu stricto were phylogenetically characterized. The toxin profile of A. catenella was dominated by GTX4, while P. delicatissima sensu stricto showed no production of the neurotoxin domoic acid in culture conditions. The results provide base-line information for the management of harmful algal blooms in this little explored subantarctic area.

Correlación entre la actividad clínica por DAS-28 y ecografía en pacientes con artritis reumatoide / Correlation between clinical activity measured by DAS-28 and ultrasound in patients with rheumatoid arthritis

INTRODUCCIÓN: La artritis reumatoide es una enfermedad multifactorial, sistémica, crónica, autoinmune e inflamatoria, que afecta fundamentalmente las articulaciones. La ultrasonografía/ecografía ha demostrado utilidad en la detección de sinovitis subclínica; sin embargo, la mayoría de la evidencia disponible es en pacientes en remisión y la evidencia para la correlación con el índice de actividad clínica (DAS-28), en Colombia, es limitada. OBJETIVOS: Establecer la correlación entre la actividad clínica medida por DAS-28 y la ecografía, en pacientes con artritis reumatoide. MATERIALES Y MÉTODOS: Cuarenta pacientes con diagnóstico de artritis reumatoide que iniciaron terapia biológica o leflunomida, fueron incluidos en el estudio descriptivo, longitudinal, prospectivo para evaluar la correlación entre el DAS-28 y la ecografía, en la consulta basal y a los 4 meses.RESULTADOS: Se encontró; correlación entre el índice de actividad clínico de la enfermedad (DAS-28) y el índice de actividad ecográfico (DAS ecográfico), tanto por escala de grises (r=0,943,p<0,01) como por Power Doppler(r =0,946, p <0,01); también se encontró; correlación entre el DAS ecográfico por escala de grises y el DAS ecográfico por Power Doppler (r= 0,953 ,p <0,01). CONCLUSIONES: La ecografía es de utilidad en la detección de inflamación subclínica y los resultados son concluyentes cuando se compara el número de articulaciones inflamadas en la evaluación clínica, con el conteo obtenido en la evaluación ecográfica. La evaluación ecográfica sugiere que las manos son las articulaciones con mejor rendimiento para la medición del grado de sinovitis en la artritis reumatoide

NTRODUCTION: Rheumatoid arthritis is a multifactorial, systemic, chronic, autoimmune, and inflammatory disease that mainly affects the joints. Ultrasound has shown to be useful in detecting subclinical synovitis; however, most of the available evidence is in patients on remission, and the evidence on a correlation with the clinical activity measured by DAS-28, in our midst, is limited. OBJECTIVE: To establish the correlation between clinical activity measured by DAS-28 and ultrasound in patients with rheumatoid arthritis. MATERIALS AND METHODS: A total of 40 patients diagnosed with rheumatoid arthritis who were started on biological therapy or leflunomide were included in the descriptive, longitudinal, prospective study to evaluate the correlation between DAS-28 and ultrasound at baseline visit and 4 months later. RESULTS: A correlation was found between DAS-28 and ultrasound, both by using the grayscale (r = 0.943, p <.01) and the power Doppler (r = 0.946, p <.01). There was also a correlation between the ultrasound DAS by grayscale and ultrasound DAS by power Doppler (r = 0.953, p<.01). CONCLUSIONS: Ultrasound is a useful tool for detecting sub-clinical inflammation and the results are conclusive when comparing the number of swollen joints in the clinical evaluation with the count obtained in the ultrasound assessment. Ultrasound evaluation suggests that the hands are the joints with better performance for measuring the grade of synovitis in rheumatoid arthritis

Costos directos del tratamiento de pacientes con artritis reumatoide en Medellín, Colombia / Direct treatment-cost of patients with rheumatoid arthritis in Medellín, Colombia

Objetivo: analizar variables clínicas y costos directos de una muestra de pacientes con artritis reumatoide atendidos en un centro de gestión farmacoterapéutica avanzada en Medellín, Colombia. Métodos: revisamos 408 historias clínicas del período 2007-2009 recogiendo información clínica y costos directos para el asegurador. Resultados: 337 mujeres (82,6%), edad promedio 49,8 años (rango 4-91). Costo promedio mes $1,31 millones en 2007, $1,71 millones en 2008 y $1,99 millones en 2009; 87,9% del costo está representado por medicamentos. Conclusiones: los costos de tratamiento van en aumento, los medicamentos representan una proporción importante del costo total.

Objective: to analyze clinical variables and direct costs of a sample of patients with rheumatoid arthritis from a specialized pharmacotherapeutic management center in Medellin, Colombia. Methods: we reviewed 408 clinical files of the period 2007-2009 collecting clinical information and direct costs to a local private health insurer. Results: 337 women (82.6%), average age 49.8 (range 4-91). Average monthly cost increased from Col$1.31 million (around US$650) in 2007, to Col$1.71 million (~US$850) in 2008, and Col$1.99 million (~US$1000) in 2009; 87.9% of this cost represented by pharmaceuticals. Conclusions: costs of treatment are increasing, pharmaceuticals represent an important proportion of total cost.

Toxin variability in cultured and natural populations of Alexandrium tamarense from southern South America - Evidences of diversity and environmental regulation.

Cell content and composition of paralytic shellfish toxins of 10 cultured strains and 6 natural populations of Alexandrium tamarense from the Argentine sea, were analyzed. These data were compiled with previously published data into a comprehensive view of the toxin composition of the complex A. tamarense/Alexandrium catenella from southern South America. The N-sulfocarbamoyl derivatives C1,2 were predominant in almost all the cultured strains. The second major derivatives were GTX1,4, although the GTX1,4/C1,2 ratio varied largely. Some strains contain relatively high amounts of GTX2,3 (up to 29%) and/or neoSTX (up to 24%). In all strains STX was a minor component (0-4.4%) whereas GTX5 was present only in Alexandrium catenella isolates. Similarity analysis based upon toxin profiles showed that cultured strains from Argentine, Brazil, Chile and Uruguay clustered together. However, whereas some strains from the same geographic area exhibited different toxin profiles, and consistently fell out in separate subgroups, strains from Chile are grouped in a unique subgroup. In contrast to cultured strains, C1,2 were minor components among field populations. The highly toxic GTX1,4 were predominant in all spring field populations (69.1-93.6%). Moreover, their toxin cell content (163.9-261.4 fmol cell(-1)) and toxicity (68.2-93.0 pg STX equiv. cell(-1)) were several times higher that showed by the cultured strains. Field populations are more closely related to one another than to the cultured strains. However a less toxic and morphologically distinctive autumn population, contained GTX2,3 as the quasi unique (88.5%) toxin derivative clustered separately. Variability in toxin content and composition of A. tamarense field populations were well correlated with in situ temperature and nitrate concentration. Whereas toxin cell content and GTX1,4 (mol %) increased following saturation functions, GTX2,3 (mol %) decrease exponentially with the increase of the in situ nitrate concentration.

Biotransformation of mycosporine like amino acids (MAAs) in the toxic dinoflagellate Alexandrium tamarense.

Changes in mycosporine-like amino acids (MAAs) induced by the increase of photosynthetically active radiation (PAR) were studied in the toxic dinoflagellate Alexandrium tamarense. Cultures of A. tamarense were maintained at exponential growth under low (25 micromol quanta m(-2)s(-1)) PAR irradiance. The cultures were nutrient enriched and one day later exposed to higher irradiance (150 micromol quanta m(-2)s(-1)). The content of MAAs was determined by means of high performance liquid chromatography (HPLC). Eleven MAAs, including some partially characterized compounds, were identified. The MAAs synthesis induction can be described as a two-stage process. The first one involves the net synthesis of the MAAs bi-substituted by amino acids. In the second stage these compounds were transformed into other secondary MAAs. The two most prominent changes were observed in the concentration of porphyra-334 and palythene. The cellular concentration of porphyra-334 increased during the first 2h of exposure to higher irradiance and then decreased rapidly. In contrast, the cellular concentration of palythene showed a continuous accumulation since the beginning of the exposure. In A. tamarense the main route of MAAs transformation has porphyra-334 as a precursor of a sequential conversion resulting in the accumulation of palythene.