Titanium Dioxide Nanoparticles Increase Sensitivity in the Next Generation of the Water Flea Daphnia magna

The nanoparticle industry is expected to become a trillion dollar business in the near future. Therefore, the unintentional introduction of nanoparticles into the environment is increasingly likely. However, currently applied risk-assessment practices require further adaptation to accommodate the intrinsic nature of engineered nanoparticles. Combining a chronic flow-through exposure system with subsequent acute toxicity tests for the standard test organism Daphnia magna, we found that juvenile offspring of adults that were previously exposed to titanium dioxide nanoparticles exhibit a significantly increased sensitivity to titanium dioxide nanoparticles compared with the offspring of unexposed adults, as displayed by lower 96 h-EC₅₀ values. This observation is particularly remarkable because adults exhibited no differences among treatments in terms of typically assessed endpoints, such as sensitivity, number of offspring, or energy reserves. Hence, the present study suggests that ecotoxicological research requires further development to include the assessment of the environmental risks of nanoparticles for the next and hence not directly exposed generation, which is currently not included in standard test protocols.     

Human macroecology: linking pattern and process in big‐picture human ecology

Humans have a dual nature. We are subject to the same natural laws and forces as other species yet dominate global ecology and exhibit enormous variation in energy use, cultural diversity, and apparent social organization. We suggest scientists tackle these challenges with a macroecological approach—using comparative statistical techniques to identify deep patterns of variation in large datasets and to test for causal mechanisms. We show the power of a metabolic perspective for interpreting these patterns and suggesting possible underlying mechanisms, one that focuses on the exchange of energy and materials within and among human societies and with the biophysical environment. Examples on human foraging ecology, life history, space use, population structure, disease ecology, cultural and linguistic diversity patterns, and industrial and urban systems showcase the power and promise of this approach.     

The role of salt marshes in the Mira estuary (Portugal)

The Mira estuary is a narrow entrenched pristine estuary of the Ria type, about 30 km long. It comprises an area of 285 ha of salt marsh, of which250 ha have been proposed for reclamation for aquaculture. Dredging, village and recreation development menace the yet undisturbed estuarine ecosystem. To assess the biological importance of this wetland, a multidisciplinary study was conducted in apart of the salt marsh, considered as being representative of the whole area. Halophytic vegetation covering 75% of the total salt marsh site is dominated by Spartina maritima (28% of total vegetation area). Total primary production attains63,766 kg/yr (dw). A net export of 1541 kg/yr of COM to the relatively oligotrophic adjacent waters was also found. Insects and birds are described for the first time in the saltmarsh. Macrobenthic communities are dominated by Hediste diversicolor, Nepthys caeca and Scrobicularia plana. The fiddler crabUca tangeri attains here its north distribution limit. The mud flats and creeks associated with the salt marsh act as a nursery for 40.8% of the fish species present. The food web is dominated by detritivorous species like the grey mullets. The results obtained in this study support the need for an effective conservation of this area. This revised version was published online in July 2006 with corrections to the Cover Date.     

Exome Sequence Reveals Mutations in CoA Synthase as a Cause of Neurodegeneration with Brain Iron Accumulation

Neurodegeneration with brain iron accumulation (NBIA) comprises a clinically and genetically heterogeneous group of disorders with progressive extrapyramidal signs and neurological deterioration, characterized by iron accumulation in the basal ganglia. Exome sequencing revealed the presence of recessive missense mutations in COASY, encoding coenzyme A (CoA) synthase in one NBIA-affected subject. A second unrelated individual carrying mutations in COASY was identified by Sanger sequence analysis. CoA synthase is a bifunctional enzyme catalyzing the final steps of CoA biosynthesis by coupling phosphopantetheine with ATP to form dephospho-CoA and its subsequent phosphorylation to generate CoA. We demonstrate alterations in RNA and protein expression levels of CoA synthase, as well as CoA amount, in fibroblasts derived from the two clinical cases and in yeast. This is the second inborn error of coenzyme A biosynthesis to be implicated in NBIA.     

Myocardial Feature Tracking Reduces Observer-Dependence in Low-Dose Dobutamine Stress Cardiovascular Magnetic Resonance

Objectives

To determine whether quantitative wall motion assessment by CMR myocardial feature tracking (CMR-FT) would reduce the impact of observer experience as compared to visual analysis in patients with ischemic cardiomyopathy (ICM).

Methods

15 consecutive patients with ICM referred for assessment of hibernating myocardium were studied at 3 Tesla using SSFP cine images at rest and during low dose dobutamine stress (5 and 10 μg/kg/min of dobutamine). Conventional visual, qualitative analysis was performed independently and blinded by an experienced and an inexperienced reader, followed by post-processing of the same images by CMR-FT to quantify subendocardial and subepicardial circumferential (Ecc_endo and Ecc_epi) and radial (Err) strain. Receiver operator characteristics (ROC) were assessed for each strain parameter and operator to detect the presence of inotropic reserve as visually defined by the experienced observer.

Results

141 segments with wall motion abnormalities at rest were eligible for the analysis. Visual scoring of wall motion at rest and during dobutamine was significantly different between the experienced and the inexperienced observer (p<0.001). All strain values (Ecc_endo, Ecc_epi and Err) derived during dobutamine stress (5 and 10 μg/kg/min) showed similar diagnostic accuracy for the detection of contractile reserve for both operators with no differences in ROC (p>0.05). Eccendo was the most accurate (AUC of 0.76, 10 μg/kg/min of dobutamine) parameter. Diagnostic accuracy was worse for resting strain with differences between operators for Ecc_endo and Ecc_epi (p<0.05) but not Err (p>0.05).

Conclusion

Whilst visual analysis remains highly dependent on operator experience, quantitative CMR-FT analysis of myocardial wall mechanics during DS-CMR provides diagnostic accuracy for the detection of inotropic reserve regardless of operator experience and hence may improve diagnostic robustness of low-dose DS-CMR in clinical practice.     

Encapsulation in Polymeric Microparticles Improves Daptomycin Activity Against Mature Staphylococci Biofilms—a Thermal and Imaging Study

Eradication of Gram-positive biofilms is a critical aspect in implant-associated infection treatment. Although antibiotic-containing particulate carriers may be a promising strategy for overcoming biofilm tolerance, the assessment of their interaction with biofilms has not been fully explored. In the present work, the antibiofilm activity of daptomycin- and vancomycin-loaded poly(methyl methacrylate) (PMMA) and PMMA-Eudragit RL 100 (EUD) microparticles against methicillin-resistant Staphylococcus aureus (MRSA) and polysaccharide intercellular adhesin-positive S. epidermidis biofilms was investigated using isothermal microcalorimetry (IMC) and fluorescence in situ hybridization (FISH). The minimal biofilm inhibitory concentrations (MBIC) of MRSA biofilms, as determined by IMC, were 5 and 20 mg/mL for daptomycin- and vancomycin-loaded PMMA microparticles, respectively. S. epidermidis biofilms were less susceptible, with a MBIC of 20 mg/mL for daptomycin-loaded PMMA microparticles. Vancomycin-loaded microparticles were ineffective. Adding EUD to the formulation caused a 4- and 16-fold reduction of the MBIC values of daptomycin-loaded microparticles for S. aureus and S. epidermidis, respectively. FISH corroborated the IMC results and provided additional insights on the antibiofilm effect of these particles. According to microscopic analysis, only daptomycin-loaded PMMA-EUD microparticles were causing a pronounced reduction in biofilm mass for both strains. Taken together, although IMC indicated that a biofilm inhibition was achieved, microscopy showed that the biofilm was not eradicated and still contained FISH-positive, presumably viable bacteria, thus indicating that combining the two techniques is essential to fully assess the effect of microparticles on staphylococcal biofilms.     

Population genetics of wild-type CAG repeats in the Machado-Joseph disease gene in Portugal

OBJECTIVE: To gain insights on the molecular mechanisms of mutation that led to the emergence of expanded alleles in the MJD gene, by studying the behavior of wild-type alleles and testing the association of its distribution with the representation of the disease. METHODS: The number of CAG motifs in the MJD gene was determined in a representative sample of 1000 unrelated individuals. Associations between the repeat size and the epidemiological representation of MJD were tested. RESULTS: The allelic profile of the total sample was in the normal range (13-41 repeats), with mode (CAG)23. No intermediate alleles were present. Allelic size distribution showed a negative skew. The correlation between the epidemiological representation of MJD in each district and the frequency of small, medium and large normal alleles was not significant. Further correlations performed grouping the districts also failed to produce significant results. CONCLUSIONS: The absence of association between the size of the repeats and the representation of MJD demonstrates that prevalence is not an indirect reflection of the frequency of large normal alleles. Globally the results obtained are in accordance with a model that postulates the occurrence of a few mutations on the basis of most of the MJD cases worldwide.     

Domain-based assays of individual antibody concentrations in an oligoclonal combination targeting a single protein

Quantitation of individual monoclonal antibodies (mAbs) within a combined antibody drug product is required for preclinical and clinical drug development, including pharmacokinetic (PK), toxicology, stability, and biochemical characterization studies of such drugs. We have developed an antitoxin, XOMA 3AB, consisting of three recombinant mAbs that potently neutralize the known subtypes of type A botulinum neurotoxin (BoNT/A). The three mAbs bind nonoverlapping BoNT/A epitopes with high affinity. XOMA 3AB is being developed as a treatment for botulism resulting from BoNT/A. To develop antibody-specific assays, we cloned, expressed, and purified BoNT/A domains from Escherichia coli. Each mAb bound only to its specific domain with affinity comparable to the binding to holotoxin. mAb-specific domains were used to develop an enzyme-linked immunosorbent assay (ELISA) for characterization of the integrity and binding activity of the three mAbs in the drug product. An electrochemiluminescence bridging assay that is robust to interference from components in serum was also developed, and we demonstrate that it can be used for PK assays. This type of antigen engineering to generate mAb-specific domains is a general method allowing quantitation and characterization of individual mAbs in a mAb cocktail that binds the same protein and is superior to anti-idiotype approaches.     

Plasma diacylglycerol composition is a biomarker of metabolic syndrome onset in rhesus monkeys

Metabolic syndrome is linked with obesity and is often first identified clinically by elevated BMI and elevated levels of fasting blood glucose that are generally secondary to insulin resistance. Using the highly translatable rhesus monkey (Macaca mulatta) model, we asked if metabolic syndrome risk could be identified earlier. The study involved 16 overweight but healthy, euglycemic monkeys, one-half of which spontaneously developed metabolic syndrome over the course of 2 years while the other half remained healthy. We conducted a series of biometric and plasma measures focusing on adiposity, lipid metabolism, and adipose tissue-derived hormones, which led to a diagnosis of metabolic syndrome in the insulin-resistant animals. Plasma fatty acid composition was determined by gas chromatography for cholesteryl ester, FFA, diacylglycerol (DAG), phospholipid, and triacylglycerol lipid classes; plasma lipoprotein profiles were generated by NMR; and circulating levels of adipose-derived signaling peptides were determined by ELISA. We identified biomarker models including a DAG model, two lipoprotein models, and a multiterm model that includes the adipose-derived peptide adiponectin. Correlations among circulating lipids and lipoproteins revealed shifts in lipid metabolism during disease development. We propose that lipid profiling may be valuable for early metabolic syndrome detection in a clinical setting.     

Three-Year Improvements in Weight Status and Weight-Related Behaviors in Middle School Students: The Healthy Choices Study

Introduction

Few dissemination evaluations exist to document the effectiveness of evidence-based childhood obesity interventions outside the research setting.

Objective

Evaluate Healthy Choices (HC), a multi-component obesity prevention program, by examining school-level changes in weight-related behaviors and weight status and the association of implementation components with odds of overweight/obesity.

Methods

We compared baseline and Year 3 school-level behavioral and weight status outcomes with paired t-tests adjusted for schools’ socio-demographic characteristics. We used generalized estimating equations to examine the odds of overweight/obesity associated with program components.

Setting/Participants

Consecutive sample of 45 of 51 middle schools participating in the HC program with complete baseline and follow-up survey data including a subsample of 35 schools with measured anthropomentry for 5,665 7^th grade students.

Intervention

Schools developed a multi-disciplinary team and implemented an obesity prevention curriculum, before and after school activities, environmental and policy changes and health promotions targeting a 5-2-1 theme: eat ≥ 5 servings/day of fruits and vegetables (FV), watch ≤ 2 hours of television (TV) and participate in ≥ 1 hours/day of physical activity (PA) on most days

Main Outcome Measures

1) School-level percent of students achieving targeted behaviors and percent overweight/obese; and 2) individual odds of overweight/obesity.

Results

The percent achieving behavioral goals over three years increased significantly for FV: 16.4 to 19.4 (p = 0.001), TV: 53.4 to 58.2 (p = 0.003) and PA: 37.1 to 39.9 (p = 0.02), adjusting for school size, baseline mean age and percent female, non-Hispanic White, and eligible for free and reduced price lunch. In 35 schools with anthropometry, the percent of overweight/obese 7^th grade students decreased from 42.1 to 38.4 (p = 0.016). Having a team that met the HC definition was associated with lower odds of overweight/obesity (OR = 0.83, CI: 0.71–0.98).

Conclusions and Relevance

The HC multi-component intervention demonstrated three-year improvements in weight-related behaviors and weight status across diverse middle schools. Team building appears important to the program’s effectiveness.