100 years of anthropogenic impact causes changes in freshwater functional biodiversity

Despite efforts from scientists and regulators, biodiversity is declining at an alarming rate. Unless we find transformative solutions to preserve biodiversity, future generations may not be able to enjoy nature's services. We have developed a conceptual framework that establishes the links between biodiversity dynamics and abiotic change through time and space using artificial intelligence. Here, we apply this framework to a freshwater ecosystem with a known history of human impact and study 100 years of community-level biodiversity, climate change and chemical pollution trends. We apply explainable network models with multimodal learning to community-level functional biodiversity measured with multilocus metabarcoding, to establish correlations with biocides and climate change records. We observed that the freshwater community assemblage and functionality changed over time without returning to its original state, even if the lake partially recovered in recent times. Insecticides and fungicides, combined with extreme temperature events and precipitation, explained up to 90% of the functional biodiversity changes. The community-level biodiversity approach used here reliably explained freshwater ecosystem shifts. These shifts were not observed when using traditional quality indices (e.g. Trophic Diatom Index). Our study advocates the use of high-throughput systemic approaches on long-term trends over species-focused ecological surveys to identify the environmental factors that cause loss of biodiversity and disrupt ecosystem functions.

Remobilization of pollutants during extreme flood events poses severe risks to human and environmental health

While it is well recognized that the frequency and intensity of flood events are increasing worldwide, the environmental, economic, and societal consequences of remobilization and distribution of pollutants during flood events are not widely recognized. Loss of life, damage to infrastructure, and monetary cleanup costs associated with floods are important direct effects. However, there is a lack of attention towards the indirect effects of pollutants that are remobilized and redistributed during such catastrophic flood events, particularly considering the known toxic effects of substances present in flood-prone areas. The global examination of floods caused by a range of extreme events (e.g., heavy rainfall, tsunamis, extra- and tropical storms) and subsequent distribution of sediment-bound pollutants are needed to improve interdisciplinary investigations. Such examinations will aid in the remediation and management action plans necessary to tackle issues of environmental pollution from flooding. River basin-wide and coastal lowland action plans need to balance the opposing goals of flood retention, catchment conservation, and economical use of water.

The Time Machine framework: monitoring and prediction of biodiversity loss

Transdisciplinary solutions are needed to achieve the sustainability of ecosystem services for future generations. We propose a framework to identify the causes of ecosystem function loss and to forecast the future of ecosystem services under different climate and pollution scenarios. The framework (i) applies an artificial intelligence (AI) time-series analysis to identify relationships among environmental change, biodiversity dynamics and ecosystem functions; (ii) validates relationships between loss of biodiversity and environmental change in fabricated ecosystems; and (iii) forecasts the likely future of ecosystem services and their socioeconomic impact under different pollution and climate scenarios. We illustrate the framework by applying it to watersheds, and provide system-level approaches that enable natural capital restoration by associating multidecadal biodiversity changes to chemical pollution.

Is a liver comparable to a liver? A comparison of different rat-derived S9-fractions with a biotechnological animal-free alternative in the Ames fluctuation assay

Metabolism has to be considered during the toxicological assessment of chemical and environmental samples because it is an important process in the mammalian liver. It can be assessed in vitro via liver homogenates called S9-fractions, an external metabolic activation system. However, the external metabolic activation systems can vary greatly in their composition due to biological variations among individual animals and animal strains that the S9-fraction are derived as well as the differences in the production treatment. To gain more insight into these variances, three different but commonly used rat-derived S9-fractions were compared in the present study for their variance and performance with a reference compound in the Ames fluctuation assay with Salmonella typhimurium strains TA 98 and TA 100 according to ISO 11350. Severe shortcomings of conventional rat-derived S9-fractions were observed in the present study, such that S9-fractions differed significantly within the same rat strain and for different types of induction procedures in regards to the metabolic capability. An intrinsic mutagenic potential of the three rat-derived S9-fractions were identified in the Ames fluctuation assay with varying S9-fraction concentrations. To address some of the shortcomings of the animal-derived S9-fraction, the present study investigated the use and performance of a biotechnological, animal-free alternative, ewoS9R, in comparison to one of the rat-derived S9-fraction as the others showed a mutagenic potential themselves. Specifically, 12 different chemicals were used as a reference to determine if ewoS9R could serve as an adequate and more consistent replacement of traditional rat-derived metabolic activation systems: 8 pro-mutagenic compounds (i.e., require metabolic activation to show a mutagenic potential), one pro-mutagenic compound but not in the tested strains, one mutagenic compound without metabolic activation and two compounds that are equivocal in the literature. EwoS9R was evaluated as a promising approach in the Ames fluctuation assay with 5 compounds observed to have similar results with both rat-derived S9-fraction and ewoS9R (41%), for 3 compounds ewoS9R was a better metabolization system than the rat-derived S9-fraction (16%). Further research is necessary to determine the full potential of ewoS9R in comparison to rat-derived S9-fractions.

Bioavailability and impacts of estrogenic compounds from suspended sediment on rainbow trout (Oncorhynchus mykiss)

Numerous environmental pollutants have the potential to accumulate in sediments, and among them are endocrine-disrupting chemicals (EDCs). It is well documented that water-borne exposure concentrations of some potent EDCs, more specifically estrogenic- active compounds (ECs), can impair the reproduction of fish. In contrast, little is known about the bioavailability and effects of sediment-associated ECs on fish. Particularly, when sediments are disturbed, e.g., during flood events, chemicals may be released from the sediment and become bioavailable. The main objectives of this study were to evaluate a) whether ECs from the sediment become bioavailable to fish when the sediment is suspended, and b) whether such exposure leads to endocrine responses in fish. Juvenile rainbow trout (Oncorhynchus mykiss) were exposed over 21 days to constantly suspended sediments in the following treatments: i) a contaminated sediment from the Luppe River, representing a "hotspot" for EC accumulation, ii) a reference sediment (exhibiting only background contamination), iii) three dilutions, 2-, 4- and 8-fold of Luppe sediment diluted with the reference sediment, and iv) a water-only control. Measured estrogenic activity using in vitro bioassays as well as target analysis of nonylphenol and estrone via LC-MS/MS in sediment, water, fish plasma, as well as bile samples, confirmed that ECs became bioavailable from the sediment during suspension. ECs were dissolved in the water phase, as indicated by passive samplers, and were readily taken up by the exposed trout. An estrogenic response of fish to Luppe sediment was indicated by increased abundance of transcripts of typical estrogen responsive genes, i.e. vitelline envelope protein α in the liver and vitellogenin induction in the skin mucus. Altered gene expression profiles of trout in response to suspended sediment from the Luppe River suggest that in addition to ECs a number of other contaminants such as dioxins, polychlorinated biphenyls (PCBs) and heavy metals were remobilized during suspension. The results of the present study demonstrated that sediments not only function as a sink for ECs but can turn into a significant source of pollution when sediments are resuspended as during flood-events. This highlights the need for sediment quality criteria considering bioavailability sediment-bound contaminants in context of flood events.

Using a high-throughput method in the micronucleus assay to compare animal-free with rat-derived S9

This study presents a high-throughput (HTP) micronucleus assay in multi-well plates with an automated evaluation for risk assessment applications. The evaluation of genotoxicity via the micronucleus assays according to international guidelines ISO 21427-2 with Chinese hamster (Cricetulus griseus) V79 cells was the starting point to develop our methodology. A drawback of this assay is that it is very time consuming and cost intensive. Our HTP micronucleus assay in a 48-well plate format allows for the simultaneous assessment of five different sample-concentrations with additional positive, negative and solvent controls with six technical replicates each within a quarter of the time required for the equivalent evaluation using the traditional slide method. In accordance with the 3R principle, animal compounds should be replaced with animal-free alternatives. However, traditional cell culture-based methods still require animal derived compounds like rat-liver derived S9-fraction, which is used to simulate the mammalian metabolism in in vitro assays that do show intrinsic metabolization capabilities. In the present study, a recently developed animal-free biotechnological alternative (ewoS9R) was investigated in the new high-throughput micronucleus assay. In total, 12 different mutagenic or genotoxic chemicals were investigated to assess the potential use of the animal-free metabolization system (ewoS9R) in comparison to a common rat-derived product. Out of the 12 compounds, one compound did not induce micronuclei in any treatment and 2 substances showed a genotoxic potential without the need for a metabolization system. EwoS9R demonstrated promising potential for future applications as it shows comparable results to the rat-derived S9 for 6 of the 9 pro-genotoxic substances tested. The remaining 3 substances (2-Acetamidofluorene, Benzo[a]pyrene, Cyclophosphamide) were only metabolized by rat-derived S9. A potential explanation is that ewoS9R was investigated with an approx. 10-fold lower enzyme concentration and was only optimized for CYP1A metabolization that may be improved with a modified production procedure. Future applications of ewoS9R go beyond the micronucleus assay, but further research is necessary.

Assessing endocrine disruption in freshwater fish species from a "hotspot" for estrogenic activity in sediment

Little is known about sediment-bound exposure of fish to endocrine disrupting chemicals (EDC) under field conditions. This study aimed to investigate potential routes of EDC exposure to fish and whether sediment-bound contaminants contribute towards exposure in fish. Tench (Tinca tinca) and roach (Rutilus rutilus) as a benthic and pelagic living fish species, respectively, were sampled at the Luppe River, previously described as a "hotspot" for accumulation of EDC in sediment. A field reference site, the Laucha River, additionally to fish from a commercial fish farm as reference were studied. Blackworms, Lumbriculus variegatus, which are a source of prey for fish, were exposed to sediment of the Luppe River and estrogenic activity of worm tissue was investigated using in vitro bioassays. A 153-fold greater estrogenic activity was measured using in vitro bioassays in sediment of the Luppe River compared the Laucha River. Nonylphenol (NP; 22 mg/kg) was previously identified as one of the main drivers of estrogenic activity in Luppe sediment. Estrogenic activity of Luppe exposed worm tissue (14 ng 17β-estradiol equivalents/mg) indicated that food might act as secondary source to EDCs. While there were no differences in concentrations of NP in plasma of tench from the Luppe and Laucha, vitellogenin, a biomarker for exposure to EDCs, was induced in male tench and roach from the Luppe River compared to both the Laucha and cultured fish by a factor of 264 and 90, respectively. However, no histological alterations in testis of these fish were observed. Our findings suggest that sediments substantially contribute to the overall EDC exposure of both benthic and pelagic fish but that the exposure did not impact gonad status of the fish.

Bioavailability of estrogenic compounds from sediment in the context of flood events evaluated by passive sampling

Studies worldwide have demonstrated through in vitro bioassays and chemical analysis that endocrine-disrupting chemicals (EDCs) can accumulate in river sediments. However, remobilization of sediment-bound EDCs due to bioturbation or re-suspension during flood events remains poorly understood. The aim of this study was to evaluate the bioavailability of EDCs, more specifically estrogenic compounds (EC), from sediment under turbulent conditions using a passive sampling approach. Sediment was sampled along the Luppe River, Germany, previously described as a "hotspot" for ECs. The concentration of target ECs and estrogenic activity were investigated using chemical analysis (LC MS/MS) in addition to a novel screening tool (planar Yeast Estrogen Screen; p-YES) that utilizes high performance thin-layer chromatography plates in combination with an in vitro bioassay (YES). Estrone (50%, E1) and nonylphenol (35%, NP) accounted for the majority of estrogenic activity reported of up to 20 ± 2.4 μg E2 equivalents per kg dry weight in the Luppe sediments. Two types of passive samplers (polar organic chemical integrative sampler (POCIS) and Chemcatcher) were used to investigate the bioavailability of ECs from suspended sediment under laboratory conditions. NP, E1, E2 and ethynylestradiol (EE2) were remobilized from Luppe sediment when subjected to turbulent conditions, such as in a flood event, and were readily bioavailable at ecotoxicologically relevant concentrations (NP 18 μg/L, E1 14 ng/L, E2 0.2 ng/L, EE2 0.5 ng/L).

Marine microplastics bound dioxin-like chemicals: Model explanation and risk assessment

Microplastics have become one of the most pervasive emerging pollutants in the marine environment because of their wide occurrence and high sorption ability for hydrophobic organic contaminants (HOCs). Among the associated HOCs, dioxin-like chemicals (DLCs) can pose severe health risks; however, information on effects of microplastics bound DLCs is lacking. To fill this knowledge gap, this study integrated chemical analysis and in vitro bioassays to elucidate the potential dioxin-like effects of microplastics bound DLCs. Chemical analysis results demonstrated that styrofoams possessed significantly greater DLCs than other coastal or open ocean plastic particles. This was probably due to the presence of additives and greater sorption ability of expanded polystyrene. However, styrofoams did not show as strong dioxin-like effects as predicted by the bioanalysis equivalent model in bioassays. This could be attributed to the decreased DLC bioavailability and increased competition with the presence of styrene oligomers. Besides, bioassay results also demonstrated that aging increased the associated DLC concentrations, since extra sorption from surrounding environment occurred during prolonged retention periods. Finally, it was estimated that the leaching of DLCs could induce dioxin-like effects in marine organisms under 100% (11/11) and 18% (2/11) scenarios for aged pellets and styrofoams through aqueous or dietary exposures.

Effect-based and chemical analyses of agonistic and antagonistic endocrine disruptors in multiple matrices of eutrophic freshwaters

In the present study, both bioanalytical and instrumental tools were employed to examine the endocrine-disruptive potentials of water samples, cyanobloom samples, and sediment samples collected from in the northern region of Taihu Lake (China) during cyanobloom season. Results from cell-based bioassays suggested the occurrence of estrogenic, anti-estrogenic, anti-androgenic, and anti-glucocorticogenic activities, while no androgenic and glucocorticogenic activities were observed in the collected samples. Using an UPLC-MS/MS system, 29 endocrine disrupting compounds including seven estrogens, seven androgens, six progestogens, and five adrenocortical hormones and four industrial pollutants were simultaneously detected. 17, 20 and 12 chemicals were detected at least in one of the water samples, cyanobloom samples and sediment samples, respectively. Since both agonistic and antagonistic endocrine-disruptive activities were detected in the present study, commonly used receptor-based in vitro bioassays resulted in net effects, suggesting that the hormone receptor agonistic potentials might be underestimated with this practice. The EDCs detected in cyanobloom samples also highlight the necessity to consider the phytoplankton matrix for understanding the mass fluxes of endocrine disruptors in eutrophic freshwaters and to consider it in monitoring strategies.

Cyanobacterial blooms act as sink and source of endocrine disruptors in the third largest freshwater lake in China

Cyanobacterial blooms are of global concern due to the multiple harmful risks they pose towards aquatic ecosystem and human health. However, information on the fate of organic pollutants mediated by cyanobacterial blooms in eutrophic water remains elusive. In the present study, endocrine disruptive potentials of phytoplankton samples were evaluated throughout a year-long surveillance in a large and eutrophic freshwater lake. Severe cyanobacterial blooms persisted during our sampling campaigns. Estrogenic agonistic, anti-estrogenic, anti-androgenic, and anti-glucocorticogenic effects were observed in the phytoplankton samples using in vitro reporter gene bioassays. 27 endocrine disrupting chemicals (EDCs) of different modes of action were detected in the samples via UPLC-MS/MS system. Results from mass balance analysis indicated that the measured estrogenic activities were greater than the predicted estrogenic potencies from chemical analysis, demonstrating that chemical analysis of targeted EDCs is unable to fully explain the compounds responsible for the observed estrogenicities. Results from Spearman's correlation analysis concluded that the concentrations of ten EDCs in phytoplankton samples were negatively correlated with cyanobacterial biomass, suggesting the potential occurrence of biomass bio-dilution effects of EDCs due to the huge biomass of cyanobacteria during bloom seasons. The present study provided complementary information about the potential endocrine disruptive risks of cyanobacterial blooms, which is important for understanding and regulating EDCs in eutrophic lakes.

Face-to-face upright seated positioning for cataract surgery in patients unable to lie flat: Case series of 240 consecutive phacoemulsifications

PURPOSE

To present a case series of patients who were unable to lie flat for cataract surgery.

SETTING

University teaching hospital, district hospital, and private practice, Norwich, United Kingdom.

DESIGN

Prospective case series.

METHODS

All patients had phacoemulsification using face-to-face upright seated positioning. The patient sits upright or semi-recumbent, and the surgeon sits or stands, facing the patient. The microscope is rotated forward, and surgery is done via an incision in the lower half of the cornea, using topical intracameral anesthesia. All 240 face-to-face cases, performed by the same surgeon, were prospectively recorded. The database included reasons for positioning difficulty, position adopted, and per-operative complications. Data on full systemic monitoring of 34 patients and satisfaction data on 90 patients were also recorded.

RESULTS

In 13 years, 240 eyes (179 patients) had face-to-face surgery. Common diagnoses were severe kyphosis, orthopnea, or both. No patient was refused face-to-face surgery since the service was started. The rate of vitreous loss was 12 (5%) of 240 cases. However, all patients (100%) received a posterior chamber intraocular lens. No patient had any systemic adverse event, and vital signs remained stable during surgery. All respondents stated that they would be happy to have face-to-face positioning again.

CONCLUSIONS

Face-to-face positioning, in the hands of an experienced surgeon, was an acceptably safe approach for patients unable to lie flat for cataract surgery. It might be the only option for some patients. However, all patients should be counseled regarding the increased risk for operative complications.

Effect-based trigger values for in vitro and in vivo bioassays performed on surface water extracts supporting the environmental quality standards (EQS) of the European Water Framework Directive

Effect-based methods including cell-based bioassays, reporter gene assays and whole-organism assays have been applied for decades in water quality monitoring and testing of enriched solid-phase extracts. There is no common EU-wide agreement on what level of bioassay response in water extracts is acceptable. At present, bioassay results are only benchmarked against each other but not against a consented measure of chemical water quality. The EU environmental quality standards (EQS) differentiate between acceptable and unacceptable surface water concentrations for individual chemicals but cannot capture the thousands of chemicals in water and their biological action as mixtures. We developed a method that reads across from existing EQS and includes additional mixture considerations with the goal that the derived effect-based trigger values (EBT) indicate acceptable risk for complex mixtures as they occur in surface water. Advantages and limitations of various approaches to read across from EQS are discussed and distilled to an algorithm that translates EQS into their corresponding bioanalytical equivalent concentrations (BEQ). The proposed EBT derivation method was applied to 48 in vitro bioassays with 32 of them having sufficient information to yield preliminary EBTs. To assess the practicability and robustness of the proposed approach, we compared the tentative EBTs with observed environmental effects. The proposed method only gives guidance on how to derive EBTs but does not propose final EBTs for implementation. The EBTs for some bioassays such as those for estrogenicity are already mature and could be implemented into regulation in the near future, while for others it will still take a few iterations until we can be confident of the power of the proposed EBTs to differentiate good from poor water quality with respect to chemical contamination.

Looking back - Looking forward: A novel multi-time slice weight-of-evidence approach for defining reference conditions to assess the impact of human activities on lake systems

Lake ecosystems are sensitive recorders of environmental changes that provide continuous archives at annual to decadal resolution over thousands of years. The systematic investigation of land use changes and emission of pollutants archived in Holocene lake sediments as well as the reconstruction of contamination, background conditions, and sensitivity of lake systems offer an ideal opportunity to study environmental dynamics and consequences of anthropogenic impact that increasingly pose risks to human well-being. This paper discusses the use of sediment and other lines of evidence in providing a record of historical and current contamination in lake ecosystems. We present a novel approach to investigate impacts from human activities using chemical-analytical, bioanalytical, ecological, paleolimnological, paleoecotoxicological, archeological as well as modeling techniques. This multi-time slice weight-of-evidence (WOE) approach will generate knowledge on conditions prior to anthropogenic influence and provide knowledge to (i) create a better understanding of the effects of anthropogenic disturbances on biodiversity, (ii) assess water quality by using quantitative data on historical pollution and persistence of pollutants archived over thousands of years in sediments, and (iii) define environmental threshold values using modeling methods. This technique may be applied in order to gain insights into reference conditions of surface and ground waters in catchments with a long history of land use and human impact, which is still a major need that is currently not yet addressed within the context of the European Water Framework Directive.

Predicting the bioavailability of sediment-bound uranium to the freshwater midge (Chironomus dilutus) using physicochemical properties

Assessment of uranium (U)-contaminated sediment is often hindered by the inability to accurately account for the physicochemical properties of sediment that modify U bioavailability. The present goal was to determine whether sediment-associated U bioavailability could be predicted over a wide range of conditions and sediment properties using simple regressions and a geochemical speciation model, the Windermere Humic Aqueous Model (WHAM7). Data from a U-contaminated field sediment bioaccumulation test, along with previously published bioaccumulation studies with U-spiked field and formulated sediments, were used to examine the models. Observed U concentrations in Chironomus dilutus larvae exposed to U-spiked and U-contaminated sediments correlated well (r²  > 0.74, p < 0.001) with the WHAM-calculated concentration of U bound to humic acid, indicating that humic acid may be a suitable surrogate for U binding sites (biotic ligands) in C. dilutus larvae. Subsequently, the concentration of U in C. dilutus was predicted with WHAM7 by numerically optimizing the equivalent mass of humic acid per gram of organism. The predicted concentrations of U in C. dilutus larvae exposed to U-spiked and U-contaminated field sediment compared well with the observed values, where one of the regression models provided a slightly better fit (mean absolute error = 18.1 mg U/kg dry wt) than WHAM7 (mean absolute error = 34.2 mg U/kg dry wt). The regression model provides a predictive capacity with a minimal number of variables, whereas WHAM7 provides additional complementary insight into the chemical variables influencing the speciation, sorption, and bioavailability of U in sediment. The present results indicate that physicochemical properties of sediment can be used to account for variability in U bioavailability as measured through bioaccumulation in chironomids exposed to U-contaminated sediments. Environ Toxicol Chem 2018;37:1146-1157. © 2017 SETAC.

Project house water: a novel interdisciplinary framework to assess the environmental and socioeconomic consequences of flood-related impacts

Protecting our water resources in terms of quality and quantity is considered one of the big challenges of the twenty-first century, which requires global and multidisciplinary solutions. A specific threat to water resources, in particular, is the increased occurrence and frequency of flood events due to climate change which has significant environmental and socioeconomic impacts. In addition to climate change, flooding (or subsequent erosion and run-off) may be exacerbated by, or result from, land use activities, obstruction of waterways, or urbanization of floodplains, as well as mining and other anthropogenic activities that alter natural flow regimes. Climate change and other anthropogenic induced flood events threaten the quantity of water as well as the quality of ecosystems and associated aquatic life. The quality of water can be significantly reduced through the unintentional distribution of pollutants, damage of infrastructure, and distribution of sediments and suspended materials during flood events. To understand and predict how flood events and associated distribution of pollutants may impact ecosystem and human health, as well as infrastructure, large-scale interdisciplinary collaborative efforts are required, which involve ecotoxicologists, hydrologists, chemists, geoscientists, water engineers, and socioeconomists. The research network "project house water" consists of a number of experts from a wide range of disciplines and was established to improve our current understanding of flood events and associated societal and environmental impacts. The concept of project house and similar seed fund and boost fund projects was established by the RWTH Aachen University within the framework of the German excellence initiative with support of the German research foundation (DFG) to promote and fund interdisciplinary research projects and provide a platform for scientists to collaborate on innovative, challenging research. Project house water consists of six proof-of-concept studies in very diverse and interdisciplinary areas of research (ecotoxicology, water, and chemical process engineering, geography, sociology, economy). The goal is to promote and foster high-quality research in the areas of water research and flood-risk assessments that combine and build off-laboratory experiments with modeling, monitoring, and surveys, as well as the use of applied methods and techniques across a variety of disciplines.

Green Toxicology: a strategy for sustainable chemical and material development

Green Toxicology refers to the application of predictive toxicology in the sustainable development and production of new less harmful materials and chemicals, subsequently reducing waste and exposure. Built upon the foundation of "Green Chemistry" and "Green Engineering", "Green Toxicology" aims to shape future manufacturing processes and safe synthesis of chemicals in terms of environmental and human health impacts. Being an integral part of Green Chemistry, the principles of Green Toxicology amplify the role of health-related aspects for the benefit of consumers and the environment, in addition to being economical for manufacturing companies. Due to the costly development and preparation of new materials and chemicals for market entry, it is no longer practical to ignore the safety and environmental status of new products during product development stages. However, this is only possible if toxicologists and chemists work together early on in the development of materials and chemicals to utilize safe design strategies and innovative in vitro and in silico tools. This paper discusses some of the most relevant aspects, advances and limitations of the emergence of Green Toxicology from the perspective of different industry and research groups. The integration of new testing methods and strategies in product development, testing and regulation stages are presented with examples of the application of in silico, omics and in vitro methods. Other tools for Green Toxicology, including the reduction of animal testing, alternative test methods, and read-across approaches are also discussed.

The role of sediment properties and solution pH in the adsorption of uranium(VI) to freshwater sediments

Uranium (U) can enter aquatic environments from natural and anthropogenic processes, accumulating in sediments to concentrations that could, if bioavailable, adversely affect benthic organisms. To better predict the sorption and mobility of U in aquatic ecosystems, we investigated the sediment-solution partition coefficients (K_d) of U for nine uncontaminated freshwater sediments with a wide range of physicochemical characteristics over an environmentally relevant pH range. Test solutions were reconstituted to mimic water quality conditions and U(VI) concentrations (0.023-2.3 mg U/L) found downstream of Canadian U mines. Adsorption of U(VI) to each sediment was greatest at pH 6 and 7, and significantly reduced at pH 8. There were significant differences in pH-dependent sorption among sediments with different physicochemical properties, with sorption increasing up until thresholds of 12% total organic carbon, 37% fine fraction (≤50 μm), and 29 g/kg of iron content. The K_d values for U(VI) were predicted using the Windermere Humic Aqueous Model (WHAM) using total U(VI) concentrations, and water and sediment physicochemical parameters. Predicted K_d-U values were generally within a factor of three of the observed values. These results improve the understanding and assessment of U sorption to field sediment, and quantify the relationship with sediment properties that may influence the bioavailability and ecological risk of U-contaminated sediments.

Sediment properties influencing the bioavailability of uranium to Chironomus dilutus larvae in spiked field sediments

The partitioning of metals between dissolved and solid phases directly affects metal bioavailability to benthic invertebrates and is influenced by metal-binding properties of sediment phases. Little research has been done examining the effects of sediment properties on the bioavailability of uranium (U) to freshwater benthic invertebrates. In the present study, 18 field sediments with a wide range of properties (total organic carbon, fine fraction, cation exchange capacity, and iron content) were amended with the same concentrations of U to characterize the effects of these sediment properties on U bioavailability to freshwater midge, Chironomus dilutus. Bioaccumulation of U by C. dilutus larvae varied by over an order of magnitude when exposed to sediments spiked with 50 mg U kg(-1) d.w. (5-69 mg U kg(-1) d.w.) and 500 mg U kg(-1) d.w. (20-452 mg U kg(-1) d.w.), depending on the type of sediment. Variance in U bioaccumulation was best explained by differences in the cation exchange capacity, fine fraction (≤50 μm particle size), and Fe content of U-spiked sediment, with generated regression equations predicting observed bioaccumulation within a factor of two. The presented regression equations offer an easy-to-apply method for accounting for the influence of sediment properties on U bioavailability in freshwater sediment, with fine fraction being the single most practical variable. This research strongly supports that risk assessments and guidelines for U-contaminated sediments should not ignore the influence of sediment properties that can result in substantial differences in the bioaccumulation of U in benthic invertebrates.

Lithium in patients with amyotrophic lateral sclerosis (LiCALS): a phase 3 multicentre, randomised, double-blind, placebo-controlled trial

Background

Lithium has neuroprotective effects in cell and animal models of amyotrophic lateral sclerosis (ALS), and a small pilot study in patients with ALS showed a significant effect of lithium on survival. We aimed to assess whether lithium improves survival in patients with ALS.

Methods

The lithium carbonate in amyotrophic lateral sclerosis (LiCALS) trial is a randomised, double-blind, placebo-controlled trial of oral lithium taken daily for 18 months in patients with ALS. Patients aged at least 18 years who had ALS according to the revised El Escorial criteria, had disease duration between 6 and 36 months, and were taking riluzole were recruited from ten centres in the UK. Patients were randomly assigned (1:1) to receive either lithium or matched placebo tablets. Randomisation was via an online system done at the level of the individual by block randomisation with randomly varying block sizes, stratified by study centre and site of disease onset (limb or bulbar). All patients and assessing study personnel were masked to treatment assignment. The primary endpoint was the rate of survival at 18 months and was analysed by intention to treat. This study is registered with Eudract, number 2008-006891-31.

Findings

Between May 26, 2009, and Nov 10, 2011, 243 patients were screened, 214 of whom were randomly assigned to receive lithium (107 patients) or placebo (107 patients). Two patients discontinued treatment and one died before the target therapeutic lithium concentration could be achieved. 63 (59%) of 107 patients in the placebo group and 54 (50%) of 107 patients in the lithium group were alive at 18 months. The survival functions did not differ significantly between groups (Mantel-Cox log-rank χ² on 1 df=1·64; p=0·20). After adjusting for study centre and site of onset using logistic regression, the relative odds of survival at 18 months (lithium vs placebo) was 0·71 (95% CI 0·40–1·24). 56 patients in the placebo group and 61 in the lithium group had at least one serious adverse event.

Interpretation

We found no evidence of benefit of lithium on survival in patients with ALS, but nor were there safety concerns, which had been identified in previous studies with less conventional designs. This finding emphasises the importance of pursuing adequately powered trials with clear endpoints when testing new treatments.

Funding

The Motor Neurone Disease Association of Great Britain and Northern Ireland.

Case-control study of risk factors for the development of post-transplant lymphoproliferative disease in a pediatric heart transplant cohort

PTLD is an important complication following heart transplantation. To better define the risk factors of PTLD in children, we performed a case-control study. All pediatric cardiac transplant recipients who developed their first episode of PTLD were matched by age (+/-1 yr) and time since transplant (+/-1 yr) with those who did not. PTLD occurred in nine of 95 cardiac transplant recipients (9%), 0.3-7.8 yr following cardiac transplantation (median = 2.5 yr). Patients were 0.1-16.4 yr (median = 3.7) at transplantation. Biopsies revealed polymorphic B cell hyperplasia (three), polymorphic B cell lymphoma (one), monomorphic diffuse large cell B cell lymphoma (three) and monomorphic Burkitt's-like lymphoma (two). Patients who developed PTLD were at no greater risk of death (p = 0.31). Recipient EBV seronegativity at time of transplant (p = 0.08), EBV seroconversion (p = 0.013) and recipient CMV seronegativity (p = 0.015) were associated with the development of PTLD by conditional logistic regression; sex, race, donor age, recipient diagnosis, donor CMV seropositivity, recipient treatment for CMV infection, EBV seropositivity at the time of PTLD diagnosis, and number of rejection episodes, treated rejection episodes, and lympholytics used were not. There was no significant association between PTLD and death in our recipients. EBV seroconversion and recipient CMV seronegativity were associated with the development of PTLD.

Rotavirus proteins: structure and assembly

Rotavirus is a major pathogen of infantile gastroenteritis. It is a large and complex virus with a multilayered capsid organization that integrates the determinants of host specificity, cell entry, and the enzymatic functions necessary for endogenous transcription of the genome that consists of 11 dsRNA segments. These segments encode six structural and six nonstructural proteins. In the last few years, there has been substantial progress in our understanding of both the structural and functional aspects of a variety of molecular processes involved in the replication of this virus. Studies leading to this progress using of a variety of structural and biochemical techniques including the recent application of RNA interference technology have uncovered several unique and intriguing features related to viral morphogenesis. This review focuses on our current understanding of the structural basis of the molecular processes that govern the replication of rotavirus.

Rotavirus NSP4 induces a novel vesicular compartment regulated by calcium and associated with viroplasms

Rotavirus is a major cause of infantile viral gastroenteritis. Rotavirus nonstructural protein 4 (NSP4) has pleiotropic properties and functions in viral morphogenesis as well as pathogenesis. Recent reports show that the inhibition of NSP4 expression by small interfering RNAs leads to alteration of the production and distribution of other viral proteins and mRNA synthesis, suggesting that NSP4 also affects virus replication by unknown mechanisms. This report describes studies aimed at correlating the localization of intracellular NSP4 in cells with its functions. To be able to follow the localization of NSP4, we fused the C terminus of full-length NSP4 with the enhanced green fluorescent protein (EGFP) and expressed this fusion protein inducibly in a HEK 293-based cell line to avoid possible cytotoxicity. NSP4-EGFP was initially localized in the endoplasmic reticulum (ER) as documented by Endo H-sensitive glycosylation and colocalization with ER marker proteins. Only a small fraction of NSP4-EGFP colocalized with the ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53. NSP4-EGFP did not enter the Golgi apparatus, in agreement with the Endo H sensitivity and a previous report that secretion of an NSP4 cleavage product generated in rotavirus-infected cells is not inhibited by brefeldin A. A significant population of expressed NSP4-EGFP was distributed in novel vesicular structures throughout the cytoplasm, not colocalizing with ER, ERGIC, Golgi, endosomal, or lysosomal markers, thus diverging from known biosynthetic pathways. The appearance of vesicular NSP4-EGFP was dependent on intracellular calcium levels, and vesicular NSP4-EGFP colocalized with the autophagosomal marker LC3. In rotavirus-infected cells, NSP4 colocalized with LC3 in cap-like structures associated with viroplasms, the site of nascent viral RNA replication, suggesting a possible new mechanism for the involvement of NSP4 in virus replication.

Angiogenesis in fatal acute Kawasaki disease coronary artery and myocardium

Angiogenesis has been shown to be dysregulated in coronary artery (CA) aneurysms in the chronic phase of Kawasaki disease (KD). Neovascularization may occur in inflammatory-related vascular diseases because many angiogenesis mediators are secreted by inflammatory cells. We hypothesized that inflammation of the acute KD CA aneurysm could lead to dysregulation of angiogenesis mediators and subsequent neovascularization. To investigate this hypothesis, acute fatal KD cardiac tissues were immunostained for angiogenic inducers and inhibitors. Microvessel density was determined and the degree of inflammation assessed. Marked inflammation and angiogenesis were found in acute KD CA aneurysms and myocardium, with the highest microvessel density seen in patients who died 2-3 weeks after onset of the disease. Expression of proangiogenic proteins was higher than expression of inhibitors in KD CA aneurysms and myocardium. Angiogenesis mediators were localized to inflammatory cells in the myointima, adventitia, and myocardium. We conclude that significant neovascularization occurs in acute KD CA aneurysms and myocardium much sooner after onset of the disease than has been previously reported, that multiple angiogenesis factors are involved, and that dysregulation of angiogenesis likely contributes to KD vasculopathy.

Cardiac plasma cell granulomas: response to oral steroid treatment

Plasma cell granulomas are lesions of uncertain histogenesis arising in a variety of locations, most commonly the lung. Treatment for these lesions is complete surgical excision if possible. Unresectable pulmonary lesions respond to oral corticosteroids and radiation therapy. We report the long-term outcome of two unusual pediatric cases of cardiac plasma cell granulomas originating within the right ventricle and posterior aspect of the left ventricle. The limited literature reports advocate surgical resection for this entity, with no discussion of alternative treatment strategies for unresectable lesions. We prospectively evaluated the response to postoperative oral steroid therapy, as complete surgical excision was not possible in either case. Sequential echocardiography demonstrated additional significant reduction in the size of the masses and the patients remain asymptomatic at 9 and 5.5 years follow-up, without evidence of obstruction or recurrence. Oral corticosteroids should be considered as a treatment option for any unresectable plasma cell granuloma.

Pathogenesis of rotavirus gastroenteritis

The outcome of intestinal infection with rotaviruses is more complex than initially appreciated, and it is affected by a complex interplay of host and viral factors. Rotaviruses infect intestinal enterocytes, and the early events in infection are mediated by virus-epithelial cell interactions. Diarrhoea may be caused by several mechanisms including (i) malabsorption that occurs secondary to the destruction of enterocytes, (ii) villus ischaemia and activation of the enteric nervous system that may be evoked by release of a vasoactive agent from infected epithelial cells in the absence of significant pathologic lesions or enterocyte damage, and (iii) intestinal secretion stimulated by the intracellular or extracellular action of the rotavirus non-structural protein, NSP4, a novel enterotoxin and secretory agonist with pleiotropic properties. New studies of rotavirus infection of polarized intestinal epithelial cells show that rotaviruses infect cells differently depending on whether or not they require sialic acid for initial binding, and infection alters epithelial cell functions. NSP4 also affects epithelial cell function and interactions. NSP4 (i) induces an age- and dose-dependent diarrhoeal response in young rodents that is similar to virus-induced disease, (ii) stimulates a Ca(2+)-dependent cell permeability where the secretory response is age-dependent, and (iii) alters epithelial cell integrity. Antibody to NSP4 protects mouse pups from diarrhoea induced by homotypic and heterotypic viruses. These data support a new mechanism of rotavirus-induced diarrhoea whereby a viral enterotoxin triggers a signal transduction pathway that alters epithelial cell permeability and chloride secretion. This new information about how a gastrointestinal virus causes disease demonstrates common pathogenic mechanisms for viral and bacterial pathogens not previously appreciated. These results also suggest new approaches to prevent or treat rotavirus-induced diarrhoea.

Pigment epithelium-derived factor (PEDF) in neuroblastoma: a multifunctional mediator of Schwann cell antitumor activity

Neuroblastoma is notable for its cellular heterogeneity and unpredictable outcome. Tumors are a variable mixture of primitive malignant neuroblasts, more differentiated ganglionic cells, Schwann and endothelial cells. Although often fatal, neuroblastomas can spontaneously regress, possibly due to favorable autocrine and paracrine interactions among these cells. Here, pigment epithelium-derived factor (PEDF), a potent inhibitor of angiogenesis and inducer of neural differentiation, is shown to be produced by ganglionic cells and Schwann cells, but not by more primitive tumor cells. Although undifferentiated neuroblastoma tumor cell secretions were angiogenic primarily due to vascular endothelial growth factor, secretions of Schwann cells were anti-angiogenic due to PEDF. In addition, PEDF was the major factor responsible for Schwann cell’s ability to induce tumor cell differentiation in vitro and recombinant PEDF had the same effect in vitro and in vivo. Both the growth and the survival of Schwann cells were enhanced by PEDF. Thus PEDF may serve as a multifunctional antitumor agent in neuroblastomas, inhibiting angiogenesis while promoting the numbers of Schwann cells and differentiated tumor cells that in turn produce PEDF, suggesting that its clinical administration could stimulate a multifaceted antitumor feedback loop with the potential to limit and possibly regress tumor growth.

Thrombospondin-1, vascular endothelial growth factor and fibroblast growth factor-2 are key functional regulators of angiogenesis in the prostate

BACKGROUND

Prostate cells secrete many molecules capable of regulating angiogenesis; however, which of these actually function as essential regulators of neovascularization is not yet clear.

METHODS

Functional angiogenic mediators secreted by normal and diseased prostate cells were identified using an in vitro angiogenesis assay. These factors were quantified by immunoblot or ELISA and localized in tissue by immunohistochemistry.

RESULTS

Normal prostate epithelial cell secretions were anti-angiogenic due to inhibitory thrombospondin-1 (TSP-1) whereas this inhibitor was decreased in the pro-angiogenic secretions derived from benign prostatic hyperplasia (BPH) and cancer cells. This pro-angiogenic activity depended primarily on fibroblast growth factor-2 (FGF-2) and/or vascular endothelial growth factor (VEGF) whose secretion was increased. Immunolocalization studies confirmed that the changes detected in vitro also occurred in vivo.

CONCLUSIONS

During disease progression in the prostate, production of TSP-1, the major inhibitor, is down-regulated while that of stimulatory FGF-2 and/or VEGF rise, leading to the induction of the new vessels necessary to support tumor growth.

Differential infection of polarized epithelial cell lines by sialic acid-dependent and sialic acid-independent rotavirus strains

Infection of epithelial cells by some animal rotaviruses, but not human or most animal rotaviruses, requires the presence of N-acetylneuraminic (sialic) acid (SA) on the cell surface for efficient infectivity. To further understand how rotaviruses enter susceptible cells, six different polarized epithelial cell lines, grown on permeable filter membrane supports containing 0.4-microm pores, were infected apically or basolaterally with SA-independent or SA-dependent rotaviruses. SA-independent rotaviruses applied apically or basolaterally were capable of efficiently infecting both sides of the epithelium of all six polarized cell lines tested, while SA-dependent rotaviruses only infected efficiently through the apical surface of five of the polarized cell lines tested. Regardless of the route of virus entry, SA-dependent and SA-independent rotaviruses were released almost exclusively from the apical domain of the plasma membrane of polarized cells before monolayer disruption or cell lysis. The transepithelial electrical resistance (TER) of cells decreased at the same time, irrespective of whether infection with SA-independent rotaviruses occurred apically or basolaterally. The TER of cells infected apically with SA-dependent rotaviruses decreased earlier than that of cells infected basolaterally. Rotavirus infection decreased TER before the appearance of cytopathic effect and cell death and resulted in an increase in the paracellular permeability to [(3)H]inulin as a function of loss of TER. The presence of SA residues on either the apical or basolateral side was determined using a Texas Red-conjugated lectin, wheat germ agglutinin (WGA), which binds SA residues. WGA bound exclusively to SA residues on the apical surface of the cells, confirming the requirement for SA residues on the apical cell membrane for efficient infectivity of SA-dependent rotaviruses. These results indicate that the rotavirus SA-independent cellular receptor is present on both sides of the epithelium, but SA-dependent and SA-independent rotavirus strains infect polarized epithelial cells by different mechanisms, which may be relevant for pathogenesis and selection of vaccine strains. Finally, rotavirus-induced alterations of the epithelial barrier and paracellular permeability suggest that common mechanisms of pathogenesis may exist between viral and bacterial pathogens of the intestinal tract.

CD8 T lymphocytes and macrophages infiltrate coronary artery aneurysms in acute Kawasaki disease

The pathogenesis of coronary arterial inflammation in acute Kawasaki disease (KD) is unclear. To test the hypothesis that the KD vascular lesion is an activated T lymphocyte-dependent process, immunohistochemical studies were done on coronary artery aneurysms from 8 fatal acute KD cases by using antibodies to CD45RO (activated or memory T lymphocyte), CD8 (cytotoxic T lymphocyte), CD4 (helper T lymphocyte), HAM56 (macrophage), and CD20 (B lymphocyte). Acute KD coronary arteritis was characterized by transmural infiltration of CD45RO T lymphocytes with CD8 T lymphocytes predominating over CD4 T lymphocytes. Macrophages were present primarily in the adventitial layer; B lymphocytes were notably absent. These data lend support to the hypotheses that KD results from infection with an intracellular pathogen, such as a virus, whose antigens are presented by major histocompatibility complex class I molecules, and that CD8 T lymphocytes and macrophages are important in the pathogenesis of KD coronary aneurysms.

Healing of a free tracheal autograft is enhanced by topical vascular endothelial growth factor in an experimental rabbit model

OBJECTIVE

In 1996, we introduced the free tracheal autograft technique for repair of congenital tracheal stenosis from complete tracheal rings in infants and children. Sources of possible concern with this procedure include the potential for autograft ischemia, patch dehiscence, and recurrent stenosis. Vascular endothelial growth factor is a potent angiogenic inducer (particularly in the setting of ischemia, hypoxia, or both) and is postulated to promote tissue healing. The purpose of this study was to test the hypothesis that pretreatment of tracheal autografts with topical vascular endothelial growth factor would enhance tracheal healing.

METHODS

In a rabbit model of tracheal reconstruction (n = 32), an elliptically shaped portion of the anterior tracheal wall was excised. The excised portion of trachea was one third of the tracheal circumference and 2 cm in length (6 tracheal rings). This portion of trachea (the autograft) was soaked in either vascular endothelial growth factor (5 microg/mL, n = 16) or normal saline solution (n = 16) for 15 minutes before being reimplanted in the resultant tracheal opening. Animals were killed and autografts were examined at 2 weeks, 1 month, and 2 months postoperatively for gross and microscopic characteristics.

RESULTS

By 2 weeks, and progressing through 1 and 2 months, autografts treated with vascular endothelial growth factor, as compared with control autografts, had reduced luminal stenosis, submucosal fibrosis, and inflammatory infiltrate (P <.05). The autografts tended to become malaligned in control animals, whereas the tracheal architecture was preserved in rabbits treated with vascular endothelial growth factor. Microvascular vessel density was significantly greater in all vascular endothelial growth factor groups (P <.05) at all time intervals.

CONCLUSIONS

Topical treatment of free tracheal autografts with vascular endothelial growth factor in a rabbit tracheal reconstruction model enhanced healing, as evidenced by accelerated autograft revascularization, reduced submucosal fibrosis and inflammation, and preservation of the normal tracheal architecture. Topical vascular endothelial growth factor may improve future results of tracheal reconstruction.

Nonadherence is associated with late rejection in pediatric heart transplant recipients

OBJECTIVES

The objective was to study the impact of nonadherence on late rejection after pediatric heart transplantation.

STUDY DESIGN

This was a retrospective cohort study of cardiac transplant recipients surviving >6 months (n = 50). Patients were stratified by episodes of late rejection. End points were defined by cyclosporin A (CSA) level, CSA level variability, and patient admission of nonadherence.

RESULTS

In 15 patients there were 49 episodes of late rejection, and 37 (76%) were associated with nonadherence. Of these patients, 7 of 15 died, and 3 of 15 had transplant coronary artery disease. Risk factors for the rejection were single-parent home, non-white, older age, and higher CSA level variability. In 35 nonrejectors there were 4 deaths from sepsis, post-transplant lymphoproliferative disease, renal failure, and encephalomyelitis.

CONCLUSION

Late rejection after pediatric heart transplantation is associated with nonadherence, is common during adolescence, and is associated with poor outcome.

Trypsin cleavage stabilizes the rotavirus VP4 spike

Trypsin enhances rotavirus infectivity by an unknown mechanism. To examine the structural basis of trypsin-enhanced infectivity in rotaviruses, SA11 4F triple-layered particles (TLPs) grown in the absence (nontrypsinized rotavirus [NTR]) or presence (trypsinized rotavirus [TR]) of trypsin were characterized to determine the structure, the protein composition, and the infectivity of the particles before and after trypsin treatment. As expected, VP4 was not cleaved in NTR particles and was cleaved into VP5(*) and VP8(*) in TR particles. However, surprisingly, while the VP4 spikes were clearly visible and well ordered in the electron cryomicroscopy reconstructions of TR TLPs, they were totally absent in the reconstructions of NTR TLPs. Biochemical analysis with radiolabeled particles indicated that the stoichiometry of the VP4 in NTR particles was the same as that in TR particles and that the VP8(*) portion of NTR, but not TR, particles is susceptible to further proteolysis by trypsin. Taken together, these structural and biochemical data show that the VP4 spikes in the NTR TLPs are icosahedrally disordered and that they are conformationally different. Structural studies on the NTR TLPs after trypsin treatment showed that spike structure could be partially recovered. Following additional trypsin treatment, infectivity was enhanced for both NTR and TR particles, but the infectivity of NTR remained 2 logs lower than that of TR particles. Increased infectivity in these particles corresponded to additional cleavages in VP5(*), at amino acids 259, 583, and putatively 467, which are conserved in all P serotypes of human and animal group A rotaviruses and also corresponded with a structural change in VP7. These biochemical and structural results show that trypsin cleavage imparts order to VP4 spikes on de novo synthesized virus particles, and these ordered spikes make virus entry into cells more efficient.

Prevention of ischemia-induced retinopathy by the natural ocular antiangiogenic agent pigment epithelium-derived factor

Aberrant blood vessel growth in the retina that underlies the pathology of proliferative diabetic retinopathy and retinopathy of prematurity is the result of the ischemia-driven disruption of the normally antiangiogenic environment of the retina. In this study, we show that a potent inhibitor of angiogenesis found naturally in the normal eye, pigment epithelium-derived growth factor (PEDF), inhibits such aberrant blood vessel growth in a murine model of ischemia-induced retinopathy. Inhibition was proportional to dose and systemic delivery of recombinant protein at daily doses as low as 2.2 mg/kg could prevent aberrant endothelial cells from crossing the inner limiting membrane. PEDF appeared to inhibit angiogenesis by causing apoptosis of activated endothelial cells, because it induced apoptosis in cultured endothelial cells and an 8-fold increase in apoptotic endothelial cells could be detected in situ when the ischemic retinas of PEDF-treated animals were compared with vehicle-treated controls. The ability of low doses of PEDF to curtail aberrant growth of ocular endothelial cells without overt harm to retinal morphology suggests that this natural protein may be beneficial in the treatment of a variety of retinal vasculopathies.

Apoptosis occurs in isolated and banked primary mouse hepatocytes

Isolation and cryopreservation of freshly isolated hepatocytes is considered a standard procedure for the long-term storage of liver cells. However, most existing methods for banking hepatocytes do not allow sufficient recovery of viable cells to meet the needs of basic research or clinical trials of hepatocyte transplantation. The mechanisms underlying this poor rate of hepatocyte recovery are unknown. Although much of the cellular damage in freezing is caused by formation of ice crystals within the cells, this is largely prevented by the use of dimethyl sulfoxide (DMSO) and controlled rate freezing. As we demonstrated recently, necrosis does occur in primary hepatocytes following isolation and cryopreservation. In the present study, we explored the contribution of apoptosis, another form of cell death, in primary hepatocytes banked for transplantation. We evaluated apoptosis of C57BL/6J mouse primary hepatocytes using several different methods. Annexin binding and the TUNEL assay, in conjunction with flow cytometry and confocal laser scanning microscopy, revealed that the percentage of apoptotic cells was dramatically elevated in cryopreserved cells compared with that in the control group of unfrozen cells. DNA laddering detected by DNA electrophoresis in agarose gel also supported the presence of apoptosis in isolated and banked liver cells. Moreover, we found that the addition of glucose (from 10 to 20 mM) into the freezing solution (University of Wisconsin Solution) decreased the rate of apoptosis by 84% and improved the cell attachment at least fourfold in cryopreserved cells. These results suggest that apoptosis might contribute to cell death in isolated and banked primary hepatocytes.

IgA plasma cell infiltration of proximal respiratory tract, pancreas, kidney, and coronary artery in acute Kawasaki disease

The etiology and pathogenesis of Kawasaki disease (KD) remain unknown. As previously reported, in US patients with acute KD, IgA plasma cells (PCs) infiltrate the vascular wall. To determine whether IgA PCs are increased at mucosal sites in KD and to determine whether other nonvascular KD tissues are infiltrated by IgA PCs, the cells were immunolocalized and quantitated in tissue sections taken from 18 US and Japanese patients who died of acute KD and from 10 age-matched controls. IgA PCs were significantly increased in the trachea of patients who died of acute KD, compared with controls (P<.01), a finding that was similar to findings in children with fatal respiratory viral infection. IgA PCs also infiltrated coronary artery, pancreas, and kidney in all KD patients. These findings strongly support entry of the KD etiologic agent through the upper respiratory tract, resulting in an IgA immune response, with systemic spread to vascular tissue, pancreas, and kidney.

Intranasal administration of 2/6-rotavirus-like particles with mutant Escherichia coli heat-labile toxin (LT-R192G) induces antibody-secreting cell responses but not protective immunity in gnotobiotic pigs

We investigated the immunogenicity of recombinant double-layered rotavirus-like particle (2/6-VLPs) vaccines derived from simian SA11 or human (VP6) Wa and bovine RF (VP2) rotavirus strains. The 2/6-VLPs were administered to gnotobiotic pigs intranasally (i.n.) with a mutant Escherichia coli heat-labile toxin, LT-R192G (mLT), as mucosal adjuvant. Pigs were challenged with virulent Wa (P1A[8],G1) human rotavirus at postinoculation day (PID) 21 (two-dose VLP regimen) or 28 (three-dose VLP regimen). In vivo antigen-activated antibody-secreting cells (ASC) (effector B cells) and in vitro antigen-reactivated ASC (derived from memory B cells) from intestinal and systemic lymphoid tissues (duodenum, ileum, mesenteric lymph nodes [MLN], spleen, peripheral blood lymphocytes [PBL], and bone marrow lymphocytes) collected at selected times were quantitated by enzyme-linked immunospot assays. Rotavirus-specific immunoglobulin M (IgM), IgA, and IgG ASC and memory B-cell responses were detected by PID 21 or 28 in intestinal and systemic lymphoid tissues after i.n. inoculation with two or three doses of 2/6-VLPs with or without mLT. Greater mean numbers of virus-specific ASC and memory B cells in all tissues prechallenge were induced in pigs inoculated with two doses of SA11 2/6-VLPs plus mLT compared to SA11 2/6-VLPs without mLT. After challenge, anamnestic IgA and IgG ASC and memory B-cell responses were detected in intestinal lymphoid tissues of all VLP-inoculated groups, but serum virus-neutralizing antibody titers were not significantly enhanced compared to the challenged controls. Pigs inoculated with Wa-RF 2/6-VLPs (with or without mLT) developed higher anamnestic IgA and IgG ASC responses in ileum after challenge compared to pigs inoculated with SA11 2/6-VLPs (with or without mLT). Three doses of SA 11 2/6-VLP plus mLT induced the highest mean numbers of IgG memory B cells in MLN, spleen, and PBL among all groups postchallenge. However, no significant protection against diarrhea or virus shedding was evident in any of the 2/6-VLP (with or without mLT)-inoculated pigs after challenge with virulent Wa human rotavirus. These results indicate that 2/6-VLP vaccines are immunogenic in gnotobiotic pigs when inoculated i.n. and that the adjuvant mLT enhanced their immunogenicity. However, i.n. inoculation of gnotobiotic pigs with 2/6-VLPs did not confer protection against human rotavirus challenge.

Serum vascular endothelial growth factor is elevated in cystic fibrosis and decreases with treatment of acute pulmonary exacerbation

Chronic bacterial infection and neutrophilic inflammation characterize cystic fibrosis (CF) pulmonary disease. In many disorders, inflammation and angiogenesis are codependent phenomena. We previously noted excessive angiogenesis in CF tissues and elevated vascular endothelial growth factor (VEGF) in random serum samples from subjects with CF. To further explore this finding, we measured serum VEGF in 38 subjects with stable CF and in 25 subjects with other pulmonary diseases. Mean VEGF was elevated in both groups compared with reference values, but it was higher in CF: 403 +/- 280 versus 255 +/- 169 pg/ml, p = 0.02. VEGF was negatively correlated with FEV(1) in CF, r = -0.51, p = 0.007. To assess the effect of airway infection on VEGF, 10 subjects with CF were studied before and after intravenous antibiotic therapy for pulmonary exacerbation. VEGF levels decreased with antibiotic therapy, from 537 +/- 220 to 259 +/- 176 pg/ml, p = 0.001. We conclude that circulating VEGF is increased in subjects with CF and other inflammatory pulmonary disorders. In CF, VEGF elevation is related to airway infection. We speculate that increased circulating VEGF is related to chronic inflammation, which is robust in CF. Elevated circulating VEGF may result in tissue angiogenesis, furthering the progression of pulmonary disease.

Gata3 loss leads to embryonic lethality due to noradrenaline deficiency of the sympathetic nervous system

Mouse embryos deficient in Gata3 die by 11 days post coitum (d.p.c.) from pathology of undetermined origin. We recently showed that Gata3-directed lacZ expression of a 625-kb Gata3 YAC transgene in mice mimics endogenous Gata3 expression, except in thymus and the sympathoadrenal system. As this transgene failed to overcome embryonic lethality (unpublished data and ref. 3) in Gata3-/- mice, we hypothesized that a neuroendocrine deficiency in the sympathetic nervous system (SNS) might cause embryonic lethality in these mutants. We find here that null mutation of Gata3 leads to reduced accumulation of Th (encoding tyrosine hydroxylase, Th) and Dbh (dopamine beta-hydroxylase, Dbh) mRNA, whereas several other SNS genes are unaffected. We show that Th and Dbh deficiencies lead to reduced noradrenaline in the SNS, and that noradrenaline deficiency is a proximal cause of death in mutants by feeding catechol intermediates to pregnant dams, thereby partially averting Gata3 mutation-induced lethality. These older, pharmacologically rescued mutants revealed abnormalities that previously could not be detected in untreated mutants. These late embryonic defects include renal hypoplasia and developmental defects in structures derived from cephalic neural crest cells. Thus we have shown that Gata3 has a role in the differentiation of multiple cell lineages during embryogenesis.

Dexamethasone reduces the inflammatory response to cardiopulmonary bypass in children

BACKGROUND

A randomized, prospective, double-blind study of 29 children was performed to evaluate the hypothesis that dexamethasone administration prior to cardiopulmonary bypass would decrease the inflammatory mediator release and improve the postoperative clinical course.

METHODS

Fifteen children received dexamethasone (1 mg/kg intravenously) and 14 (controls) received saline solution 1 hour prior to CPB. Serial blood analyses for interleukin-6, tumor necrosis factor-alpha, complement component C3a, and absolute neutrophil count were performed. Postoperative variables evaluated included temperature, supplemental fluids, alveolar-arterial oxygen gradient, and days of mechanical ventilation.

RESULTS

Dexamethasone caused an eightfold decrease in interleukin-6 levels and a greater than threefold decrease in tumor necrosis factor-alpha levels after CPB (p < 0.05). Complement component C3a and absolute neutrophil count were not affected by dexamethasone. The mean rectal temperature for the first 24 hours postoperatively was significantly lower in the group given dexamethasone than in the controls (37.2 degrees +/- 0.4 degrees C versus 37.7 degrees +/- 4 degrees C; p = 0.007). Dexamethasone-treated patients required less supplemental fluid during the first 48 hours (22 +/- 28 mL/kg versus 47 +/- 34 mL/kg; p = 0.04). Compared with controls, dexamethasone-treated children had significantly lower alveolar-arterial oxygen gradients during the first 24 hours (144 +/- 108 mm Hg versus 214 +/- 118 mm Hg; p = 0.02) and required less mechanical ventilation (median duration, 3 days versus 5 days; p = 0.02).

CONCLUSIONS

Dexamethasone administration prior to CPB in children leads to a reduction in the postbypass inflammatory response as assessed by cytokine levels and clinical course.

Reversal of severe late left ventricular failure after pediatric heart transplantation and possible role of plasmapheresis

Late acute cardiac graft failure carries a high mortality in adults. Vascular mediators and factors other than classic T-cell-mediated rejection may play a role in this process, and aggressive multimodality therapy may improve survival. We report experience with plasmapheresis in treating late severe acute left ventricular dysfunction in a group of pediatric heart transplant recipients. We retrospectively reviewed clinical records, echocardiograms, hemodynamics, coronary angiograms, biopsy specimens, and treatment regimens for 5 patients with 7 episodes of late-onset severe graft failure who recovered. Plasmapheresis was applied in all cases, in addition to methylprednisolone, cyclophosphamide, lympholytic agents, and aggressive supportive care including mechanical ventilation and hemofiltration. All patients presented with acute severe left ventricular dysfunction 1.4 to 7.9 years (mean 3.6) after orthotopic heart transplantation. Mean shortening fraction at presentation was 13 to 23% (mean 16), initial endomyocardial biopsy specimens were grade 0 to 3B, and immunofluorescence studies were negative. Treatment included plasmapheresis, cyclophosphamide, mechanical ventilation, hemofiltration, and inotropes. Clinical recovery was slow, with 4 to 8 weeks until left ventricular function normalized, and 2.2 to 9.4 (mean 4.6) weeks to hospital discharge. At follow-up (50 to 38 months, mean 24), all are alive. Two patients are well, whereas coronary vasculopathy developed in 3. Thus, survival may improve in patients with late graft failure with low biopsy score and plasmapheresis combined with multimodality therapy.

Signals leading to apoptosis-dependent inhibition of neovascularization by thrombospondin-1

Thrombospondin-1 (TSP-1) is a naturally occurring inhibitor of angiogenesis that limits vessel density in normal tissues and curtails tumor growth. Here, we show that the inhibition of angiogenesis in vitro and in vivo and the induction of apoptosis by thrombospondin-1 all required the sequential activation of CD36, p59fyn, caspase-3 like proteases and p38 mitogen-activated protein kinases. We also detected increased endothelial cell apoptosis in situ at the margins of tumors in mice treated with thrombospondin-1. These results indicate that thrombospondin-1, and possibly other broad-spectrum natural inhibitors of angiogenesis, act in vivo by inducing receptor-mediated apoptosis in activated microvascular endothelial cells.

Pigment epithelium-derived factor: a potent inhibitor of angiogenesis

In the absence of disease, the vasculature of the mammalian eye is quiescent, in part because of the action of angiogenic inhibitors that prevent vessels from invading the cornea and vitreous. Here, an inhibitor responsible for the avascularity of these ocular compartments is identified as pigment epithelium-derived factor (PEDF), a protein previously shown to have neurotrophic activity. The amount of inhibitory PEDF produced by retinal cells was positively correlated with oxygen concentrations, suggesting that its loss plays a permissive role in ischemia-driven retinal neovascularization. These results suggest that PEDF may be of therapeutic use, especially in retinopathies where pathological neovascularization compromises vision and leads to blindness.

Dobutamine stress echocardiography: experience in pediatric heart transplant recipients

BACKGROUND

Transplant coronary arteriopathy causes late death and is difficult to detect noninvasively. Dobutamine stress echocardiography is being used for risk stratification in adult recipients at some transplant centers, thus we investigated its role in a pediatric population.

METHODS

We performed 46 stress echo studies (mean age = 11.8 years; mean years post transplantation = 4.3). An atropine/dobutamine protocol (5-40 mcg/kg/min) was used to attain a predicted target heart rate. Serial echocardiographic images were acquired at baseline and at each increment of dobutamine and recovery, and were digitized online. Data were correlated with endomyocardial biopsy (n = 23), coronary angiography (n = 26) or autopsy (n = 6). All studies were well tolerated.

RESULTS

Target heart rate was achieved in 41/46 (89%) studies. The mean heart rate significantly increased from 95 to 169 beats/min and mean systolic blood pressure from 123 to 153 mm Hg (p<.05). The mean peak pressure-rate product was 23,041 beats-mm Hg/min. Coronary arteriopathy was confirmed in 5 patients by angiography (n = 3) explanted heart (n = 1) or autopsy (n = 4). In this group, abnormalities included a new reversible wall motion abnormality (n = 2), left ventricular cavity dilation with stress (n = 3), ischemia (n = 2), increased mitral insufficiency (n = 1) and marked diastolic dysfunction (n = 1). A positive study predicted death or graft failure (p< .0005).

CONCLUSIONS

Echocardiographic abnormalities during stress correlated with coronary arteriopathy in this small cohort of patients; however, larger multi-center studies are warranted to assess the utility of dobutamine stress echocardiography for risk stratification for coronary disease in pediatric transplant recipients.

Heterotypic protection and induction of a broad heterotypic neutralization response by rotavirus-like particles

The recognition that rotaviruses are the major cause of life-threatening diarrheal disease and significant morbidity in young children has focused efforts on disease prevention and control of these viruses. Although the correlates of protection in children remain unclear, some studies indicate that serotype-specific antibody is important. Based on this premise, current live attenuated reassortant rotavirus vaccines include the four predominant serotypes of virus. We are evaluating subunit rotavirus vaccines, 2/6/7-VLPs and 2/4/6/7-VLPs, that contain only a single VP7 of serotype G1 or G3. In mice immunized parenterally twice, G3 virus-like particles (VLPs) induced a homotypic, whereas G1 VLPs induced a homotypic and heterotypic (G3) serum neutralizing immune response. Administration of three doses of G1 or G3 VLPs induced serum antibodies that neutralized five of seven different serotype test viruses. The inclusion of VP4 in the VLPs was not essential for the induction of heterotypic neutralizing antibody in mice. To confirm these results in another species, rabbits were immunized parenterally with two doses of 2/4/6/7-VLPs containing a G3 or G1 VP7, sequentially with G3 VLPs followed by G1 (G3/G1) VLPs, or with live or psoralen-inactivated SA11. High-titer homotypic serum neutralizing antibody was induced in all rabbits, and low-level heterotypic neutralizing antibody was induced in a subset of rabbits. The rabbits immunized with the G1 or G3/G1 VLPs in QS-21 were challenged orally with live G3 ALA rotavirus. Protection levels were similar in rabbits immunized with homotypic G3 2/4/6/7-VLPs, heterotypic G1 2/4/6/7-VLPs, or G3/G1 2/4/6/7-VLPs. Therefore, G1 2/4/6/7-VLPs can induce protective immunity against a live heterotypic rotavirus challenge in an adjuvant with potential use in humans. Following challenge, broad serum heterotypic neutralizing antibody responses were detected in rabbits parenterally immunized with G1, G3/G1, or G3 VLPs but not with SA11. Immunization with VLPs may provide sufficient priming of the immune system to induce protective anamnestic heterotypic neutralizing antibody responses upon subsequent rotavirus infection. Therefore, a limited number of serotypes of VLPs may be sufficient to provide a broadly protective subunit vaccine.

Plasma clearance and liver uptake of chylomicron remnants generated by hepatic lipase lipolysis: evidence for a lactoferrin-sensitive and apolipoprotein E-independent pathway

Chylomicrons labeled with [3H]cholesterol and [14C]triglyceride fatty acids were lipolyzed by hepatic lipase (HL) in vitro and then injected intravenously into normal mice fed low- or high-fat diets, and into apolipoprotein (apo) E-deficient mice. In normal mice fed the high-fat diet and injected with non-lipolyzed chylomicrons, the plasma clearance and hepatic uptake of the resulting [3H]cholesterol-labeled remnants was markedly inhibited. In contrast, chylomicrons lipolyzed by HL were taken up equally rapidly by the livers of mice fed the low- and high-fat diets. The removal of non-lipolyzed chylomicrons lacking apoE from the plasma of apoE-deficient mice was inhibited, but not the removal of chylomicrons lipolyzed by HL. Pre-injection of lactoferrin into normal mice inhibited the plasma clearance of both non-lipolyzed chylomicrons and chylomicrons lipolyzed by HL. The removal of HL from the surface of the lipolyzed particles by proteolytic digestion did not affect their rapid uptake, indicating that the hepatic recognition of the lipoproteins was not mediated by HL. These observations support previous findings that phospholipolysis of chylomicrons by hepatic lipase generates remnant particles that are rapidly cleared from circulation by the liver. They also support the concept that chylomicron remnants can be taken up by the liver by an apolipoprotein E-independent mechanism. We hypothesize that this mechanism is modulated by the remnant phospholipids and that it may involve their interaction with a phospholipid-binding receptor on the surface of hepatocytes such as the class B scavenger receptor BI.

Captopril and platelet-activating factor (PAF) antagonist prevent cardiac allograft vasculopathy in rats: role of endogenous PAF and PAF-like compounds

Accelerated coronary artery disease (CAD) is the leading cause of late mortality following cardiac transplantation. The vascular lesions are characterized by myointimal proliferation and perivascular mononuclear inflammatory infiltrates. Platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a potent phospholipid mediator produced by inflammatory cells and activated endothelial cells. Angiotensin II is known to activate phospholipase A2, a critical enzyme in PAF synthesis. Using a rat heterotopic cardiac transplant model known to induce graft CAD, we previously reported that chronic administration of captopril, an angiotensin converting enzyme inhibitor, reduces intimal proliferation and maintains luminal patency. The purpose of the current study was to determine if captopril regulates vascular remodeling by suppressing PAF synthesis and whether administration of a PAF antagonist ameliorates graft CAD. Captopril was found to decrease levels of PAF and PAF-like compounds as well as reduce intimal lesions, decrease cellular rejection grade, and diminish allograft heart weights. Treatment with a PAF antagonist significantly decreased proliferation of the intimal component of the vasculopathy and caused regression of the cardiac hypertrophy, but had no significant effect on cellular rejection. In contrast, untreated animals had elevated plasma PAF levels, elevated heart weights, and severe myointimal proliferation with luminal stenosis 21 days post-transplantation. These observations suggest that graft CAD is mediated, in part, by PAF and PAF-like compounds, and suppression of endogenous PAF may prevent cardiac allograft vasculopathy.