Beached microplastics at the Bahia Blanca Estuary (Argentina): Plastic pellets as potential vectors of environmental pollution by POPs.

Microplastics (MPs) from the coastal areas of a highly anthropised estuary were sampled to assess their distribution in coastal sediments and their role as potential vectors of pollution. The average MP density was 1693 ± 2315 MPs/kg, which mainly accumulated in the high tide and storm berm areas of the beach. The Microplastic Pollution Index (MPPI), Microplastic Impact Coefficient (CMPI), Hierarchical Cluster Analysis and Principal Component Analysis revealed spatial variation in MPs pollution. High-density polyethylene plastic pellets were abundant at two beaches (192 ± 218 MPs/kg sediment). Furthermore, the presence of sorbed chemicals on pellets was assessed through GC-MS, showing 0.95 ± 0.09 ng/g of ∑7OCPs, 4.03 ± 0.89 ng/g of ∑7PCBs, 108.76 ± 12.88 ng/g of ∑16 PAHs and 122.79 ± 11.13 g/g of ∑29 PAHs. The sorption capacity of plastics, combined with their abundance, poses an environmental concern and also highlights their suitability as indicators of chemical exposure.

Microplastic levels on sandy beaches: Are the effects of tourism and coastal recreation really important?

This study assessed the effect of tourism and other recreational activities on microplastic (MP) levels and their characteristics in the sand and surf zone of the seawater. Six sites were chosen belonging to three sandy beaches with similar geomorphologic and morphodynamic characteristics but with different tourism activities. On average, a concentration of 1133.3 ± 811.3 items/kg dry weight (d.w.) and 12.7 ± 14.9 items/m3 were found in the sand and seawater samples, respectively. Fibers and films predominated and were less than 1 mm in length. In the sand, the films mainly matched the PE polymer spectra and the fibers matched PET polymer, cotton, and indigo blue dye; in the seawater samples, PP films and PET fibers prevailed. At the Pehuén-Co - Monte Hermoso Coastal Marine MPA where the flow of tourists is low, the MP levels were the lowest and the largest particles were found, mainly blue or black fibers, with less polymer diversity, cotton and PET being the most prevalent suggesting a recent input of textile fibers to this site. Moreover, the highest concentration of MPs was found on the southern site of a beach considered to be more pristine due to negligible human activity, including the smallest size pattern, mostly composed of white films or fibers with a greater diversity of polymers, predominantly PE > PET > PP. A great occurrence of PVC white films was also found in the surf zone at this site. Proximity to the mouth of a river, littoral drift, and other point sources were identified as the main sources, indicating that, apart from the local tourism and recreational activities, other sources might play a major role in the input of MPs to sandy beaches, such as extensive/intensive agricultural land use and irrigation areas.

Treatment of melasma with platelet-rich plasma: A self-controlled clinical trial.

Melasma is a common circumscribed hypermelanosis of sun-exposed areas of the skin. Platelet-Rich Plasma therapy has been evidenced to inhibit melanin synthesis in animals and humans. To determine the effectiveness of platelet-rich plasma as a treatment for melasma. Twenty female patient with melasma were involved in this study. The intervention included three Platelet-Rich Plasma application sessions at 15-day intervals. Patients were evaluated before and after treatment. Variables measured included the facial melanin concentration using the melasma area and severity index score, melasma quality of life scale satisfaction grade, and histologic changes. Mean age was 41 ± 7 years. An initial MELASQOL score of 42 ± 14.8 and final score of 16.6 ± 7.2 (p = 0.008) were reported; the initial and final MASI score were 15.5 ± 8.4 and 9.5 ± 7.2 (p = 0.001), respectively. The dermatoscopy examination revealed a decrease in pigmentation after intervention (p = 0.001). Histopathologic improvement was detected in reductions in cutaneous atrophy (14 [70%] vs. 11 [55%]), solar elastosis (15 [75%] vs.11 [55%]), and inflammatory infiltrate (9 [45%] vs. 6 [30%]), before and after treatment, respectively. The intervention was associated with decreased intensity of the melasma patch and improved skin quality, shown by the MELASQOL and MASI scores.

Bilateral vocal fold paralysis after COVID-19 infection. Another neuro-invasive manifestation? Case series / Parálisis bilateral de cuerdas vocales tras infección por COVID-19. ¿Una manifestación neuroinvasiva? Serie de casos

Abstract The agent that causes the coronavirus disease (COVID-19), associated with the severe acute respiratory syndrome (SARS-CoV-2), produces a spectrum of symptoms that mainly affect the respiratory system, the central nervous system (CNS), the regulation of hemostasis and the immune system. Bilateral vocal fold paralysis (BVFP) is a condition of unknown incidence among infected patients, either because it is short-lived or because of the difficulty in establishing a direct cause to the virus. Viral infection has been described in the literature as a cause of BVFP and there is the suspicion that a proportion of the idiopathic cases are due to undiagnosed viral infections. Although the neurotropic mechanisms for SARS-CoV-2 remain unclear, there is strong evidence to ensure its neuroinvasive potential. The most frequent etiologies of BVFP are trauma, neoplasm, and neurological, but a viral origin should not be ruled out. Causality between COVID-19 and BVFP is plausible and will require further study in the short and long term. We present a case series that support and discuss the hypothesis under consideration.

Resumen El agente causal de la enfermedad por coronavirus (COVID-19), asociado a síndrome respiratorio agudo grave (SARS-CoV-2), genera un espectro de síntomas que afectan fundamentalmente el sistema respiratorio, el sistema nervioso central (SNC), la regulación hemostásica y el sistema inmune. La parálisis bilateral de cuerdas vocales (PBCV) es una entidad cuya incidencia en infectados se desconoce, bien porque no se presentan durante el tiempo suficiente o por la dificultad de establecer una causalidad directa con el virus. La infección vírica, como causa de PBCV, está descrita en la literatura y se sospecha que una parte de los casos idiopáticos corresponden a infecciones víricas no diagnosticadas. Aunque los mecanismos neurotrópicos no están completamente aclarados para el SARS-CoV-2, existen indicios sólidos para asegurar su potencial neuroinvasivo. Las causas traumáticas, neoplásicas y neurológicas son las etiologías más comunes de PBCV, sin que se pueda descartar el origen vírico. Es plausible una causalidad entre el COVID-19 y la PBCV, que requerirá mayores estudios a corto y largo plazo. Presentamos una serie de casos que sostienen y discuten la hipótesis en consideración.

Atmospheric PAHs in rural, urban, industrial and beach locations in Buenos Aires Province, Argentina: sources and health risk assessment.

The first atmospheric PAHs levels and associated inhalation cancer risk were assessed over southwest Buenos Aires region by deploying PUF disk PAS samplers. Eight sampling location included coastal zones, touristic beaches, and rural inland areas were considered. PUF disks were fortified with surrogate standards and extracted by automated Soxhlet prior to GC-MS analysis. Σ16 PAHs ranged from 1.13 to 44.5 ng m-3 (10.3 ± 9.8), while urban locations showed up to 10 times higher PAH levels than rural or beach locations. Direct sources of PAHs, such as intensive vehicle traffic, heating, and general combustion activities, were identified. PAHs with four to six rings (46.62%) were predominantly Flt, Pyr, BbF, and BkF, and carcinogenic risk was expressed by BaP (0.10 ± 0.07 ng m-3) and BaPTEQs (0.26 ± 0.22 ng m-3). Inhalation ECR (2.23E-5, WHO) presented the lowest risk at beach locations. Molecular ratios and PCA showed a strong dominance in pyrolytic sources, such as biomass and coal combustion, with a particular signature in fires at inland locations. Overall, this study demonstrated that PUF disk passive air sampling provided a sound and simple approach for tracking air PAHs, their sources and public health risks, bringing a cost-effective tool for pollution control measures, even at small and remote towns. This is particularly relevant in extensive countries with medium or low income, such as Argentina.

Distribution of Butyltin Compounds in the Coastal Environment of the Bahía Blanca Estuary, Argentina.

This study evaluates for the first time the distribution and accumulation of butyltin compounds (BTs) in different compartments such as seawater, sediments, suspended particulate matter (SPM), and mussels (Brachidontes rodriguezii) in the Bahía Blanca estuary. The samples were collected from six sampling sites with different anthropogenic impacts. A better visualization and interpretation of data was achieved using chemometric tools (Tucker4 model), which made it possible to reveal the main relationships among the variables. This analysis showed the presence of BTs in all the estuarine environmental compartments, even in sites with low human intervention. The relationships found among BTs levels, seasons, and environmental matrices show the importance of biological processes such as phytoplankton blooms and remobilization of sediments (by tidal dynamics and/or periodic dredging) in BTs distribution and degradation. In addition, partition coefficients showed that mussels mainly bioaccumulate tributyltin from sediment, water and, to a lesser extent, SPM.

"A hybrid approach for GISTs near the esophagogastric junction, a case report".

INTRODUCTION AND IMPORTANCE: Gastrointestinal stromal tumors are the most frequent mesenchymal tumors of the gastrointestinal tract. Complete resection of GISTs is the only chance of cure for patients. When these tumors are located near the esophagogastric junction, the surgical risk can cause deformity or stenosis in the gastric inlet, leading to higher complications and diminishing their quality of life. In such cases, a more sophisticated and tailored approach should be used. CASE PRESENTATION: We present the case of a 42-year-old female; she presented to our office with a 3-year history of nausea, vomiting and abdominal distension. Two GISTs were located near the EGJ, and with a combined approach we achieved complete resection. On follow-ups, the patient is doing well. CLINICAL DISCUSSION CONCLUSION: When diagnosis is confirmed, surgical resection must be the first choice for GISTs as complete surgical excision is the only permanent cure. The rise of endoscopic surgery has become a valuable tool and a critical element in surgery. Hybrid techniques that combine laparoscopic and endoscopic approaches can improve the patient's outcomes and provide better results.

Multi-species pastures for grazing dairy cows in small-scale dairy systems in the highlands of Mexico.

Grazing in small-scale dairy systems reduces costs and enhances sustainability. However, binary pastures (BP) have low persistency, which may be increased by including more species given their flexibility to withstand different agroecological and management situations. The objective was to assess a multi-species (MS) pasture of perennial ryegrass (RG), tall fescue (TF), bromegrass (BG), red clover (RC) and white clover (WC) in comparison to a BP of perennial ryegrass (RG) - WC grazed by six Holstein dairy cows during the dry season in an on-farm double cross-over experiment, with three 14-day each experimental periods for animal variables, and a split-plot design for pasture variables at 3 cow/ha. There were differences (P < 0.05) between pastures for sward height (MS 5.0 vs. BP 4.0 ± 0.10 cm, both MS and BP) and net herbage accumulation (MS 902 vs BP 228 ± 172.4 kg DM/ha, both MS and BP) and differences (P < 0.05) for chemical composition among periods. There were differences (P < 0.01) among periods for estimated DM intake, but no differences (P > 0.05) for milk yield (mean 16.8 kg/cow/day), milk fat or protein content (mean 31.8 and 28.8 g/kg). Multi-species pastures are a viable alternative for SSDS in the highlands of central Mexico, being more resistant to harsh environment and to weed and kikuyu grass invasion.

Adenocarcinoma de células basales / Basal cell adenocarcinoma

El adenocarcinoma de células basales, también conocido como carcinoma salival basaloide, adenoma maligno de células basales, es una neoplasia epitelial de bajo grado, infiltrante, localmente destructivo y con tendencia a ser recidivante. Su aparición es entre la 5ª y 6ª década de vida, sin predilección por sexo. Clínicamente se manifiesta con un edema o un aumento repentino de tamaño en la zona, de consistencia firme, crecimiento lento e indoloro. El diagnóstico de certeza es a través de la histopatología; su tratamiento quirúrgico, y tiene buen pronóstico en sus estadios iniciales (AU)

Basal cells adenocarcinoma also known as salivary basaloide carcinoma basal cells malignant adenoma is a low degree, infiltrating, locally destructive and prone to be relapsing, epithelial neoplasia. It occurs between the 5th and 6th decade of life, with no predilection for sex. Clinically it manifests with an edema or sudden increased size in the area, of firm consistency, slow growth and pain-less. Its treatment is surgical and the diagnosis of certainty is histopathological with a good prognosis. The purpose of this presentation is to show the case of a 57- years-old male patient with clinical and anatomopathological diagnosis of adenocarcinoma of basal cells located in the yugal mucosa (AU)

Spatiotemporal distribution of organotin compounds in the coastal water of the Bahía Blanca estuary (Argentina).

Several areas within the Bahía Blanca estuary (BBE), with different maritime traffic intensity, were studied in order to confirm the presence and assess the distribution of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) in the water column. The organotin compounds (OTCs) were determined in the water samples-taken in summer, autumn, winter, and spring of 2014-by gas chromatography coupled to mass spectrometry after liquid-liquid extraction with hexane. The incidence of TBT throughout the whole sampling period indicated a continuous presence of this compound to the study area. However, in accordance with the butyltin degradation index (BDI), TBT was not recently introduced in the BBE. Furthermore, the average TBT levels exceeded the international guideline established by the Oslo-Paris commission (0.62 ng Sn L-1). As a result, certain biological effects could be expected to occur in sensitive species such as mussels. While DBT were below the detection limit in the 75% of the samples analyzed, MBT was detected in all the samples and no significant differences were found among the concentrations measured in the different seasons (Kruskal-Wallis test, p > 0.05). In addition, no correlations were found among the OTCs levels and the evaluated physiochemical parameters (Spearman coefficient, p > 0.05).

Hepatoprotective Effects of Nonpolar Extracts from Inflorescences of Thistles Cirsium vulgare and Cirsium ehrenbergii on Acute Liver Damage in Rat.

BACKGROUND: Drugs for the treatment of liver diseases are scarce and not effective enough. Some species of the genus Cirsium possess hepatoprotective activity. There are no studies on the hepatoprotective effects of nonpolar extracts from inflorescences of thistles Cirsium vulgare and Cirsium ehrenbergii, and there are few reports on their chemical composition. OBJECTIVE: The aim is to obtain the hexane extract from inflorescences of both thistles and to identify preliminarily their main chemical component, and to evaluate the hepatoprotective properties of the extracts. MATERIALS AND METHODS: Hexane extracts were obtained using a Soxhlet apparatus. The chemical composition was analyzed using infrared spectra and gas chromatography-mass spectrometry. Two doses (250 and 500 mg/kg, p.o.) of both extracts were administered to assess their hepatoprotective effect on acute carbon tetrachloride (TC)-induced liver damage in rats using biochemical markers of necrosis, cholestasis, functionality, oxidative stress, and histological analysis. RESULTS: Extracts were shown to have a very similar chemical profile. Their major constituent seems to be lupeol acetate. The two doses of both extracts demonstrated comparable hepatoprotective properties because they significantly diminished all the liver injury indicators (P < 0.05) and were corroborated using histopathology. CONCLUSION: This is the first study on the hepatoprotective effects of nonpolar extracts from inflorescences of thistles C. vulgare and C. ehrenbergii. Hexane extracts administration totally prevented the acute TC-induced liver damage. The preliminary chemical analysis strongly suggests the lupeol acetate as their major constituent. Lupeol and its derivatives have been previously reported as antiinflammatory and hepatoprotective agents. SUMMARY: Hexane extracts of both thistles kept normal liver functionality and glycogen store in carbon tetrachloride-induced acute liver damageHexane extracts of both thistles showed anti-necrotic and anti-cholestatic effects, also diminished the lipid peroxidation and nitric oxide levels on the carbon tetrachloride-induced acute liver damageThe two doses of hexane extracts administered (250 and 500 mg/kg) prevented the liver injury in a very similar extentBoth nonpolar extracts are chemically very similar and their main compound seems to be lupeol acetate. Abbreviations used: TC: Carbon tetrachloride; FT-IR: Fourier transform Infrared spectroscopy; GC-MS: Gas chromatography - Mass spectrometry; V: Vehicle; E: Extract; Ecv: Extract of Cirsium vulgare; Ece: Extract of Cirsium ehrenbergii; AP: Alkaline phosphatase; GGTP: γ-Glutamyl transpeptidase; ALT: Alanine aminotransferase; DB: Direct bilirubin; TB: Total bilirubin; LP: Lipid peroxidation; MDA: Malondialdehyde; NO: Nitric oxide; TNF-α: Tumor necrosis factor-α.

Fast and Feasible Ultrasound-Assisted Pretreatment for the Determination of Organotin Compounds in Environmental Samples.

The goal of this study was to improve an already established reference method, such as the one devoted to organotin compounds determination (Reference Method for Marine Pollution Studies, No. 59, UNEP). The proposed upgrade consists of replacing the mechanical shaking by ultrasound energy and applying low temperature throughout the whole procedure. The optimization of the new operational conditions was performed by using a factorial design. Quality control was performed using a certified sediment reference material (PACS-2) for sediments (82.5-97% of recovery) and recoveries on spiked samples for suspended particulate matter (SPM) and mussels (94-100%). The proposed procedure was applied to surface sediment samples, SPM, and native bivalve mollusks (Brachidontes rodriguezii) collected in Bahia Blanca estuary, a very industrialized zone. The relative standard deviation (RSD %) of the environmental samples were less than 7.9%. It is important to note that the proposed procedure reduced the sample pretreatment time about seven times.

Organotin compounds in Brachidontes rodriguezii mussels from the Bahía Blanca Estuary, Argentina.

Levels of tributyltin and its breakdown compounds, including the first record of monobutyltin (MBT) in history for Latin America, were determined in native mussels (Brachidontes rodriguezii) by means of CG-MS, after extraction/derivatization assisted by ultrasound. The samples were collected in 2013 in Bahía Blanca Estuary (Argentina) at 6 sites, which reflect different levels of maritime activities. Total butyltins (TBts = TBT+ DBT+ MBT) levels ranged from 19.64 to 180.57ng Sn g-1 dry weight. According to the Oslo-Paris commission, the results indicated that 73.9% of mussels could be under biological effects risks associated with TBT pollution. In accordance with the calculated bioaccumulation factors, approximately 56% of samples appeared to have accumulated TBT through the sediments. All sampling sites were shown to be impacted by organotin compounds (OTCs) showing variable levels through seasons, which could be related with the variation of the water temperature. Degradation index analyses suggested aged inputs of TBT possibly under a general degradation process at the area of study. In addition, the occurrence of DBT and MBT could not be uniquely attributed to the degradation pathway of the TBT; in fact, results outlined the possible contribution of some punctual and diffuse sources at the area such as proximity to plastic industries, industrial effluents, sewage outlets and domestic wastewaters.

Tracking polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in sediments and soils from the southwest of Buenos Aires Province, Argentina (South eastern part of the GRULAC region).

PCBs and PBDEs (7 and 10 congeners, respectively) were analyzed in four coastal surface sediments collected from the northern shore of Bahía Blanca estuary and in nine soils from different locations of Bahía Blanca city and the surrounding region (Southwest of Buenos Aires Province, Argentina). Sediment samples showed PCBs(Σ7) concentrations ranged from 0.61 to 17.6ngg-1 (dry weight=dw) and PBDEs(Σ10) from 0.16 to 2.02ngg-1 dw, whereas in soil samples ranged from 0.04 to 1.67ngg-1 dw for PCBs(Σ7) and 0.04 to 10.7ngg-1 dw for PBDEs(Σ10). The highest concentrations of both chemicals were detected in the urban and industrial/port areas showing a dominance of the higher chlorinated PCB congeners: in sediments for PCB-180 (56±33%) and PCB-153 (11±6%); and in soils for PCB-138 (23±3%), PCB-153 (22±2%) and PCB-180 (18±7%). In contrast, lower chlorinated PCB congeners were predominant at more distant sites; in sediments for congeners PCB-28 (33±4%) and PCB-52 (14.5±0.2%); and in soils PCB-28 (56±14%) and PCB-52 (33±19%). PBDE-209 (high brominated PBDE) showed the highest relative abundance in both sample types i.e., sediment (94±7%) and soil (80±12%). These findings can be considered lower or similar when compared with other sites of the world, and are likely associated with anthropogenic activities in their surrounding area, which has experienced a fast industrial growth in the last decade. This is the first investigation of PBDEs levels in the whole study area and of PCBs in soils from the Bahía Blanca city and surrounding region. This article provides new and useful information on POP levels in the South eastern part of the GRULAC region.

Ionic liquid mediated extraction, assisted by ultrasound energy, of available/mobilizable metals from sediment samples.

A new extraction method for metals from sediment samples was developed. In this procedure, the chelating agent EDTA was combined with a minimal amount of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim[BF4]), assisted by ultrasound energy. The available analytes -Cd, Cr, Cu, Ni, Pb and Zn- were extracted under optimal conditions for a 12.5 ratio (extractant volume/sample mass) with 0.005molL-1 EDTA solution, 0.1molL-1 NaHCO3, 5.0mmolL-1 Bmim[BF4] and 7.0min of sonication time, using an ultrasonic bath (output power of 160W). The best extractions were obtained with 100W (power dissipated in the liquid). These conditions were obtained applying the univariate method. It is important to highlight that the conventional method (extraction with 0.05molL-1 EDTA solution only) consumes 6h to extract available metals from sediment samples selectively, and with the proposed procedure the extraction time is noticeable reduced to 7.0min. Extractable metal concentrations obtained were measured by flame atomic absorption spectrometry. The results showed good agreement with those obtained by the conventional method using a Student's paired t-test.

Localización y clínica asociada al cáncer de colon: Hospital Nacional Arzobispo Loayza: 2009 - 2013 / Location and associated clinical characteristics of colon cancer: Hospital Nacional Arzobispo Loayza: 2009 - 2013

OBJETIVO: Determinar la clínica asociada a la localización del cáncer de colon en pacientes del Hospital Nacional Arzobispo Loayza durante el periodo mayo 2009 - setiembre 2013. MATERIAL Y MÉTODOS: estudio transversal que analizó información de 114 pacientes con neoplasia maligna primaria de colon, de los cuales 42 cumplieron los criterios de inclusión; internados en el Servicio 6-II del Departamento de Cirugía General del Hospital Nacional Arzobispo Loayza entre mayo 2009 y setiembre 2013. RESULTADOS: La media de edad fue de 60.5 años, y predominó el género femenino con 66.7%. El 100% de los tipos histológicos fue adenocarcinoma. El colon derecho resultó afectado en 61.9%, el izquierdo en 33,3% y un 4,8% presentó localización mixta. En la topografía, se halló 33,3% en colon ascendente y 21,4% en colon sigmoides. Los síntomas más frecuentes fueron dolor abdominal (76,2%), pérdida de peso (69%) y anemia (64%). Para el colon derecho, hubo 13 veces más riesgo de presentar astenia, y 4.44 veces más riesgo de presentar anemia (p<0,05). CONCLUSIÓN: La localización de cáncer de colon más frecuente fue en el colon derecho, el cual se asoció significativamente a la presencia de astenia y anemia en el cuadro clínico. Los síntomas más presentados fueron el dolor abdominal y la pérdida de peso, en cualquiera de sus localizaciones. Todos los casos fueron de adenocarcinoma. (Horiz Med 2015; 15(2): 49-55)

OBJECTIVE: To determine the association between the clinical characteristics and the location of colon cancer in patients hospitalized at "Hospital Nacional Arzobispo Loayza", during May 2009 - September 2013. MATERIAL AND METHODS: transversal study of 144 patients with primary colon cancer, of which 42 patients met the inclusion criteria; hospitalized in the 6-II Wing of the Department of General Surgery at "Hospital Nacional Arzobispo Loayza", between May 2009 and September 2013. RESULTS: the mean age was 60.5 years, and 66.7% of the cases were women. 100% of histologic types were adenocarcinoma. The right colon was affected in 61.9% of the cases; the left colon in 33.3%, and a mixed location in 4,8%. Regarding the topography, 33,3% of the cases were found in the ascending colon and 21,4% in the sigmoid colon. The most frequent symptoms were abdominal pain (76.2%), weight loss (69%) and anemia (64%). For right colon cancer, fatigue was 13 times more likely to appear, and anemia was 4.44 times more likely (p< 0.05). CONCLUSION: the most common location for cancer was in the right colon, and it was associated significantly with the presence of fatigue and anemia among the clinical characteristics. The most frequent symptoms were abdominal pain and weight loss, in any location. All cases were adenocarcinoma. (Horiz Med 2015; 15(2): 49-55)

Chemometric approach to visualize and easily interpret data from sequential extraction procedures applied to sediment samples.

The aim of this study was to assess metal mobility/availability in coastal surface (oxic) sediment samples from the Bahía Blanca estuary. Particularly, two sequential extraction procedures able to discriminate metals associated to amorphous Fe and Mn oxides and those associated with crystalline oxides of Fe were applied. Sequential procedures differ in the number of steps, type of reagents used, and in the order in which metals associated to organic matter are extracted. The studied metals were Cd, Cr, Cu, Pb, Ni and Zn because of their hazardous potential and relative abundance in the estuary. Tucker4 model with three factors describes appropriately the data sets (explained variance of 64.05%). This model made it possible to visualize and explain the information underlying in the data set. From the multivariate analysis, it was possible to evaluate the metal behaviour and their availability. In this way, Cd and Zn are associated to the more available fractions whereas Ni, Cr, Cu and Pb are mainly associated to the unavailable fractions. On the other hand, Zn and Cu are associated to organic matter fraction. Despite the fact that the two-fractionation schemes are quite different, the results obtained with both schemes are comparable.

Successful circumferential free tracheal transplantation in a large animal model.

BACKGROUND: Long segment tracheobronchial stenoses are associated with high morbi-mortality rates and difficult treatment. Transplantation hasn't proved to be useful yet. Currently, the successful results achieved in small animal models couldn't be satisfactorily accomplished or extrapolated in large mammals. We aimed to evaluate the viability of orthotopic tracheal autoimplantation in an ovine model. METHODS: All animals underwent tracheal transplantation of 4 cm (5-7 rings) of the cervical trachea and were divided randomly in two groups: isolated autoimplantation (Group A/6) and autoimplantation with omental wrapping (Group B/6). Clinical follow up and weekly bronchoscopical examinations were performed. The grafts were macroscopically, histologically, and bacteriologically analyzed. RESULTS: In group A, four animals achieved their planed survival and were sacrificed up to 60 days after transplantation with viable grafts. In group B, only two sheep had successful results. Graft failure with infection, necrosis and severe stenosis was observed in the rest of the animals from both groups. Pseudomonas aeruginose was isolated in all cases. The main complication of the omental pedicle was vascular congestion and peritracheal hemorrhage. CONCLUSIONS: Contrary to the data reported to date, we found that tracheal transplantation is viable in a large mammal like the sheep. The main complication observed in this animal model was graft infection. The use of an omental pedicle with the technique applied worsened the grafts survival. The encouraging results obtained in this investigation justify further research in order to manage graft infection, leading us to establish a suitable large animal model for allotransplantation.

Vigilancia epidemiológica de las parálisis fláccidas agudas (PFA) en menores de 15 años / Epidemiological surveillance of acute flaccid paralysis (AFP) in children under 15

Hasta el año 2006, las regiones de América, Pacífico Oriental y Europa han sido certificadas libres de la circulación autóctona del virus salvaje de la poliomielitis. En Chile, el último caso ocurrió en 1975, y en la región de las Américas en 1991. Para mantener sistemas de vigilancia eficaces a fin de erradicar la poliomielitis, se realiza la vigilancia sindromática de todo menor de 15 años que presente Parálisis Fláccida Aguda de causa no traumática. En el año 2006 ingresaron 76 casos de Parálisis Fláccida Aguda en menores de 15 años al sistema de vigilancia de poliomielitis en Chile, de los cuales, 75 fueron descartados y 1 fue clasificado como caso compatible. Este artículo, da cuenta de la situación epidemiológica de la PFA en Chile durante el año 2006 y presenta los resultados obtenidos para cada indicador de la vigilancia, tanto a nivel nacional como regional.