Combining multi-isotopic and molecular source tracking methods to identify nitrate pollution sources in surface and groundwater.

Nitrate (NO3-) pollution adversely impacts surface and groundwater quality. In recent decades, many countries have implemented measures to control and reduce anthropogenic nitrate pollution in water resources. However, to effectively implement mitigation measures at the origin of pollution,the source of nitrate must first be identified. The stable nitrogen and oxygen isotopes of NO3- (ẟ15N and ẟ18O) have been widely used to identify NO3- sources in water, and their combination with other stable isotopes such as boron (ẟ11B) has further improved nitrate source identification. However, the use of these datasets has been limited due to their overlapping isotopic ranges, mixing between sources, and/or isotopic fractionation related to physicochemical processes. To overcome these limitations, we combined a multi-isotopic analysis with fecal indicator bacteria (FIB) and microbial source tracking (MST) techniques to improve nitrate origin identification. We applied this novel approach on 149 groundwater and 39 surface water samples distributed across Catalonia (NE Spain). A further 18 wastewater treatment plant (WWTP) effluents were also isotopically and biologically characterized. The groundwater and surface water results confirm that isotopes and MST analyses were complementary and provided more reliable information on the source of nitrate contamination. The isotope and MST data agreed or partially agreed in most of the samples evaluated (79 %). This approach was especially useful for nitrate pollution tracing in surface water but was also effective in groundwater samples influenced by organic nitrate pollution. Furthermore, the findings from the WWTP effluents suggest that the use of literature values to define the isotopic ranges of anthropogenic sources can constrain interpretations. We therefore recommend that local sources be isotopically characterized for accurate interpretations. For instance, the detection of MST inferred animal influence in some WWTP effluents, but the ẟ11B values were higher than those reported in the literature for wastewater. The results of this study have been used by local water authorities to review uncertain cases and identify new vulnerable zones in Catalonia according to the European Nitrate Directive (91/676/CEE).

Insights into the reproduction of some Antarctic dendroceratid, poecilosclerid, and haplosclerid demosponges.

Sponges are a dominant element of the Antarctic benthic communities, posing both high species richness and large population densities. Despite their importance in Antarctic ecosystems, very little is known about their reproductive patterns and strategies. In our study, we surveyed the tissue of six different species for reproductive elements, namely, Dendrilla antarctica Topsent, 1905 (order Dendroceratida), Phorbas areolatus (Thiele, 1905), Kirkpatrickia variolosa (Kirkpatrick, 1907), and Isodictya kerguelenensis (Ridley & Dendy, 1886) (order Poecilosclerida), and Hemigellius pilosus (Kirkpatrick, 1907) and Haliclona penicillata (Topsent, 1908) (Haplosclerida). Samples of these six species containing various reproductive elements were collected in Deception Island and were processed for both light and transmission electron microscopy (TEM). Even though we were not able to monitor the entire reproductive cycle, due to time and meteorological conditions, we report important aspects of the reproduction of these species. This includes oocyte and embryo morphology and cell ultrastructure, follicular structures and nurse cell activity, as well as vitellogenesis. All species were brooding their embryos within their mesohyl. Both oocytes and embryos were registered in the majority of the studied species, and a single sperm cell being carried to an egg for fertilization was observed in H. penicillata. While the reproductive periods of all species coincided temporally, some of them seemed to rely on a single spawning event, this being suggested by the synchronic oogenesis and embryogenesis occurrence of D. antarctica, P. areolatus and I. kerguelenensis. In contrast, K. variolosa had an asynchronous embryo development, which suggests several larval release events. Our results suggest that differences in the reproductive strategies and morphological traits might succeed in the coexistence of these species at the same habitat avoiding the direct competition between them.

Safety and effectiveness of outpatient parenteral antimicrobial therapy in older people.

OBJECTIVES: We analyse the safety and effectiveness of self-outpatient parenteral antimicrobial therapy (s-OPAT) in older patients. METHODS: We prospectively evaluated all adults admitted to our home hospitalization unit (HHU) for s-OPAT in the period 2008-12 in whom the bacteria responsible for the infection were identified. We divided patients into three age groups: <65, 65-79 and ≥80 years. s-OPAT was administered by patients or their caregivers using elastomeric infusion devices. Effectiveness was assessed by analysing readmissions to hospital for inadequate control of underlying infection. Safety was assessed by analysing adverse events, catheter-related complications and readmission to hospital for causes unrelated to inadequate control of underlying infection. RESULTS: During the study period, 420 episodes of s-OPAT were registered in 351 patients: 139 (33.1%) in patients aged <65 years, 182 (43.3%) in those aged 65-79 years and 99 (23.6%) in those aged ≥80 years. Patients aged ≥80 years had a significantly lower Barthel index. The length of stay for s-OPAT and the complete HHU stay were similar in the three groups. Older people had similar changes in antibiotic treatment and hospital readmission rates due to poor control of underlying infection but higher readmission rates due to worsening of underlying diseases than younger adults. Adverse events and catheter-related complications were similar in the three age groups. CONCLUSIONS: s-OPAT administered by patients or their caregivers using elastomeric devices was safe and effective in the treatment of infections in older people.

Some like it fat: comparative ultrastructure of the embryo in two demosponges of the genus Mycale (order Poecilosclerida) from Antarctica and the Caribbean.

During embryogenesis, organisms with lecithotrophic indirect development usually accumulate large quantities of energetic reserves in the form of yolk that are necessary for larval survival. Since all sponges have lecithotrophic development, yolk formation is an ineludible step of their embryogenesis. Sponge yolk platelets have a wide range of morphological forms, from entirely lipid or protein platelets to a combined platelet showing both lipids and proteins and even glycogen. So far, there are no comparative studies on the nature and content of yolk in congeneric species of sponges inhabiting contrasting environments, which could have putative effects on the larval adaptation to environmental conditions. Here, we have taken advantage of the worldwide distribution of the sponge genus Mycale, in order to compare the embryogenesis and yolk formation in two species inhabiting contrasting latitudinal areas: M. acerata from Antarctic waters and M. laevis from the Caribbean. We have compared their brooded embryos and larvae using scanning and transmission electron microscopy, and calculated their energetic signatures based on the nature of their yolk. While the general morphological feature of embryos and larvae of both species were very similar, the main difference resided in the yolk nature. The Antarctic species, M. acerata, showed exclusively lipid yolk, whereas the Caribbean species, M. laevis, showed combined platelets of lipids and proteins and less frequently protein yolk platelets. The larvae of M. acerata were estimated to possess a two-fold energetic signature compared to that of M. laevis, which may have important ecological implications for their survival and for maintaining large population densities in the cold waters of the Southern Ocean.

[In-patient treatment decisions]. / Decisiones terapéuticas en los pacientes hospitalizados.

BACKGROUND AND OBJECTIVE: The aim of this study was to identify the extent to which treatment decisions for medical in-patients in three hospitals in Catalunya are supported by published evidence. PATIENTS AND METHOD: In a retrospective, cross-sectional study, main diagnosis-treatment pairs (DTPs) were identified for 980 hospital discharges. The Cochrane library and MEDLINE from 1966 to 1998 were searched for systematic reviews or, in their absence, randomized controlled clinical trials (RCT) that supported the treatment given for each diagnosis. The level of evidence found for each DTP was classified. Descriptive analyses for patients and different DTP were performed. RESULTS: A systematic review or RCT (level I) was found for 65.4% of the 980 patients. In 32.6% of cases, there was only non-experimental or consensus evidence (level II) and in 2% there was no good evidence for the treatment given (level III). An analysis of the 598 unique pairs reduced the percentage of cases supported by level I evidence (55.7) with a proportionate increase in level II (41%). There were some differences in the proportion of cases in each evidence level by diagnostic group. CONCLUSIONS: For about two thirds of patients and a half therapeutic decisions in these three centres, there was a published RCT or a systematic review, with variations according to diagnostic groups. More robust and objective instruments are needed to assess the degree to which scientific evidence is applied in clinical practice.