Effects of D- and L-glucose and mannitol on retinal capillary cells:Inhibition by nanomolar aminoguanidine

Hyperglycemia may contribute directly to pericyte loss and capillary leakage in early diabetic retinopathy. To elucidate relative contributions of glycation, glycoxidation, sugar autoxidation, osmotic stress and metabolic effects in glucose-mediated capillary damage, we tested the effects of D-glucose, L-glucose, mannitol and the potentially protective effects of aminoguanidine on cultured bovine retinal capillary pericytes and endothelial cells. Media (containing 5 mM D-glucose) were supplemented to increase the concentration of each sugar by 5, 10, or 20 mM. Subconfluent pericytes and endothelial cells were exposed to the supplemented media in the presence or absence of aminoguanidine (1 nM-100 µM) for three days. Cell counts, viability and protein were determined. For both cell types, all three sugars produced concentration-dependent decreases in cell counts and protein content (p

Evaluation of the effect of wheat aleurone-rich foods on markers of antioxidant status, inflammation and endothelial function in apparently healthy men and women

Observational data show an inverse association between the consumption of whole-grain foods, and inflammation and related diseases. Although the underlying mechanisms are unclear, whole grains, and in particular the aleurone layer, contain a wide range of components with putative antioxidant and anti-inflammatory effects. We evaluated the effects of a diet high in wheat aleurone on plasma antioxidants status, markers of inflammation and endothelial function. In this parallel, participant-blinded intervention, seventy-nine healthy, older, overweight participants (45-65 years, BMI>25 kg/m²) incorporated either aleurone-rich cereal products (27 g aleurone/d), or control products balanced for fibre and macronutrients, into their habitual diets for 4 weeks. Fasting blood samples were taken at baseline and on day 29. Results showed that, compared to control, consumption of aleurone-rich products provided substantial amounts of micronutrients and phytochemicals which may function as antioxidants. Additionally, incorporating these products into a habitual diet resulted in significantly lower plasma concentrations of the inflammatory marker, C-reactive protein (P = 0·035), which is an independent risk factor for CVD. However, no changes were observed in other markers of inflammation, antioxidant status or endothelial function. These results provide a possible mechanism underlying the beneficial effects of longer-term whole-grain intake. However, it is unclear whether this effect is owing to a specific component, or a combination of components in wheat aleurone.

Built environment interventions for increasing physical activity in adults and children

Primary objective: Assess the effects of interventions targeting increased use of the built environment for overall PA in both adults and children.
Secondary objectives

Compare the effects of interventions encouraging the use of existing built environments with interventions that, with or without involving informational approaches, involve building or regenerating environments.
Describe other health benefits (e.g. mental health, risk factors for cardiovascular and other diseases) where outcomes are available.
Explore whether the effects of interventions differ between adults and children and between advantaged and disadvantaged populations.
Identify gaps in the evidence and highlight future research needs in the area.

Periodontal systemic associations: review of the evidence

Aim: To critically appraise recent research into associations between periodontal disease and systemic diseases and conditions specifically respiratory disease, chronic kidney disease, rheumatoid arthritis, cognitive impairment, obesity, metabolic syndrome and cancer.

Methods: A MEDLINE literature search of papers published between 2002 and April 2012 was conducted. Studies that included periodontitis as an exposure were identified. Cross-sectional epidemiological investigations on large samples, prospective studies and systematic reviews formed the basis of the narrative review. A threshold set for the identification of periodontitis was used to identify those studies that contributed to the conclusions of the review.

Results: Many of the investigations were cross-sectional secondary analyses of existing data sets in particular the NHANES studies. There were a small number of systematic reviews and prospective studies. There was substantial variability in the definitions of exposure to periodontitis. A small number of studies met the threshold set for periodontitis and supported associations; however, in some of the chronic diseases there were no such studies. There was strong evidence from randomized controlled trials that interventions, which improve oral hygiene have positive effects on the prevention of nosocomial pneumonias.

Conclusions: There was substantial heterogeneity in the definitions used to identify periodontitis and very few studies met a stringent threshold for periodontitis. Published evidence supports modest associations between periodontitis and some, although not all, of the diseases and conditions reviewed. There is a need to reach a consensus on what constitutes periodontitis for future studies of putative associations with systemic diseases.

Water and temperature relations of soil Actinobacteria

Actinobacteria perform essential functions within soils, and are dependent on available water to do so. We determined the water-activity (a_w) limits for cell division of Streptomyces albidoflavus, Streptomyces rectiviolaceus, Micromonospora grisea and Micromonospora (JCM 3050) over a range of temperatures, using culture media supplemented with a biologically permissive solute (glycerol). Each species grew optimally at 0.998 a_w (control; no added glycerol) and growth rates were near-optimal in the range 0.971–0.974 (1 M glycerol) at permissive temperatures. Each was capable of cell division at 0.916–0.924 a_w (2 M glycerol), but only S. albidoflavus grew at 0.895 or 0.897 a_w (3 M glycerol, at 30 and 37°C respectively). For S. albidoflavus, however, no growth occurred on media at ≤ 0.870 (4 M glycerol) during the 40-day assessment period, regardless of temperature, and a theoretical limit of 0.877 a_w was derived by extrapolation of growth curves. This level of solute tolerance is high for non-halophilic bacteria, but is consistent with reported limits for the growth and metabolic activities of soil microbes. The limit, within the range 0.895–0.870 a_w, is very much inferior to those for obligately halophilic bacteria and extremely halophilic or xerophilic fungi, and is inconsistent with earlier reports of cell division at 0.500 a_w. These findings are discussed in relation to planetary protection policy for space exploration and the microbiology of arid soils.

Rapid single-nucleotide polymorphism-based identification of clonal Pseudomonas aeruginosa isolates from patients with cystic fibrosis by the use of real-time PCR and high-resolution melting curve analysis

Pseudomonas aeruginosa genotyping relies mainly upon DNA fingerprinting methods, which can be subjective, expensive and time-consuming. The detection of at least three different clonal P. aeruginosa strains in patients attending two cystic fibrosis (CF) centres in a single Australian city prompted the design of a non-gel-based PCR method to enable clinical microbiology laboratories to readily identify these clonal strains. We designed a detection method utilizing heat-denatured P. aeruginosa isolates and a ten-single-nucleotide polymorphism (SNP) profile. Strain differences were detected by SYBR Green-based real-time PCR and high-resolution melting curve analysis (HRM10SNP assay). Overall, 106 P. aeruginosa sputum isolates collected from 74 patients with CF, as well as five reference strains, were analysed with the HRM10SNP assay, and the results were compared with those obtained by pulsed-field gel electrophoresis (PFGE). The HRM10SNP assay accurately identified all 45 isolates as members of one of the three major clonal strains characterized by PFGE in two Brisbane CF centres (Australian epidemic strain-1, Australian epidemic strain-2 and P42) from 61 other P. aeruginosa strains from Australian CF patients and two representative overseas epidemic strain isolates. The HRM10SNP method is simple, is relatively inexpensive and can be completed in <3 h. In our setting, it could be made easily available for clinical microbiology laboratories to screen for local P. aeruginosa strains and to guide infection control policies. Further studies are needed to determine whether the HRM10SNP assay can also be modified to detect additional clonal strains that are prevalent in other CF centres.

Thermo-Mechanical Properties of Poly ε-Caprolactone/Poly L-Lactic Acid Blends: Addition of Nalidixic Acid and Polyethylene Glycol Additives Journal of the Mechanical Behavior of Biomedical Materials

The search for ideal biomaterials is still on-going for tissue regeneration. In this study, blends of Poly ε-caprolactone (PCL) with Poly l-lactic acid (PLLA), Nalidixic Acid (NA) and Polyethylene glycol (PEG) were prepared. Mechanical and thermal properties of the blends were investigated by tensile and flexural analysis, DSC, TGA, WXRD, MFI, BET, SEM and hot stage optical microscopy. Results showed that the loading of PLLA caused a significant decrease in tensile strength and almost total eradication of the elongation at break of PCL matrix, especially after PEG and NA addition. Increased stiffness was also noted with additional NA, PEG and PLLA, resulting in an increase in the flexural modulus of the blends.
Isothermal degradation indicated that bulk PCL, PLLA and the blends were thermally stable at 200°C for the duration of 2h making extrusion of the blends at this temperature viable. Morphological study showed that increasing the PLLA content and addition of the very low viscosity PEG and powder NA decreased the Melt Flow Indexer and increased the viscosity.
At the higher temperature the PLLA begins to soften and eventually melts allowing for increased flow and, coupling this with, the natural increase in MFI caused by temperature is enhanced further. The PEG and NA addition increased dramatically the pore volume which is important for cell growth and flow transport of nutrients and metabolic waste.

Antimicrobial and immunomodulatory properties of PGLa-AM1, CPF-AM1, and magainin-AM1: Potent activity against oral pathogens

Cationic amphipathic α-helical peptides are intensively studied classes of host defence peptides (HDPs). Three peptides, peptide glycine-leucine-amide (PGLa-AM1), caerulein-precursor fragment (CPF-AM1) and magainin-AM1, originally isolated from norepinephrine-stimulated skin secretions of the African volcano frog Xenopus amieti (Pipidae), were studied for their antimicrobial and immunomodulatory activities against oral and respiratory pathogens. Minimal effective concentrations (MECs), determined by radial diffusion assay, were generally lower than minimal inhibitory concentrations (MICs) determined by microbroth dilution. PGLa-AM1 and CPF-AM1 were particularly active against Streptococcus mutans and all three peptides were effective against Fusobacterium nucleatum, whereas Enterococcus faecalis and Candida albicans proved to be relatively resistant micro-organisms. A type strain of Pseudomonas aeruginosa was shown to be more susceptible than the clinical isolate studied. PGLa-AM1 displayed the greatest propensity to bind lipopolysaccharide (LPS) from Escherichia coli, P. aeruginosa and Porphyromonas gingivalis. All three peptides showed less binding to P. gingivalis LPS than to LPS from the other species studied. Oral fibroblast viability was unaffected by 50. μM peptide treatments. Production of the pro-inflammatory cytokine IL-8 by oral fibroblasts was significantly increased following treatment with 1 or 10. μM magainin-AM1 but not following treatment with PGLa-AM1 or CPF-AM1. In conclusion, as well as possessing potent antimicrobial actions, the X. amieti peptides bound to LPS from three human pathogens and had no effect on oral fibroblast viability. CPF-AM1 and PGLa-AM1 show promise as templates for the design of novel analogues for the treatment of oral and dental diseases associated with bacteria or fungi.

Size matters: plasticity in metabolic scaling shows body-size may modulate responses to climate change

Variability in metabolic scaling in animals, the relationship between metabolic rate (R) and body mass (M), has been a source of debate and controversy for decades. R is proportional to M-b, the precise value of b much debated, but historically considered equal in all organisms. Recent metabolic theory, however, predicts b to vary among species with ecology and metabolic level, and may also vary within species under different abiotic conditions. Under climate change, most species will experience increased temperatures, and marine organisms will experience the additional stressor of decreased seawater pH ('ocean acidification'). Responses to these environmental changes are modulated by myriad species-specific factors. Body-size is a fundamental biological parameter, but its modulating role is relatively unexplored. Here, we show that changes to metabolic scaling reveal asymmetric responses to stressors across body-size ranges; b is systematically decreased under increasing temperature in three grazing molluscs, indicating smaller individuals were more responsive to warming. Larger individuals were, however, more responsive to reduced seawater pH in low temperatures. These alterations to the allometry of metabolism highlight abiotic control of metabolic scaling, and indicate that responses to climate warming and ocean acidification may be modulated by body-size.

Pharmacogenetics and the print media: what is the public told?

Background: Pharmacogenetics is a rapidly growing field that aims to identify the genes that influence drug response. This science can be used as a powerful tool to tailor drug treatment to the genetic makeup of individuals. The present study explores the coverage of the topic of pharmacogenetics and its potential benefit in personalised medicine by the UK newsprint media. 

Methods: The LexisNexis database was used to identify and retrieve full text articles from the 10 highest circulation national daily newspapers and their Sunday equivalents in the UK. Content analysis of newspaper articles which referenced pharmacogenetic testing was carried out. A second researcher coded a random sample (21%) of newspaper articles to establish the inter-rater reliability of coding. 

Results: Of the 256 articles captured by the search terms, 96 articles (with pharmacogenetics as a major component) met the study inclusion criteria. The majority of articles over-stated the benefits of pharmacogenetic testing while paying less attention to the associated risks. Overall beneficial effects were mentioned 5.3 times more frequently than risks (p < 0.001). The most common illnesses for which pharmacogenetically based personalised medicine was discussed were cancer, cardiovascular disease and CNS diseases. Only 13% of newspaper articles that cited a specific scientific study mentioned this link in the article. There was a positive correlation between the size of the article and both the number of benefits and risks stated (P < 0.01). 

Conclusion: More comprehensive coverage of the area of personalised medicine within the print media is needed to inform public debate on the inclusion of pharmacogentic testing in routine practice.

Transcriptional response of T cells to IFN-alpha:changes induced in IFN-alpha-sensitive and resistant cutaneous T cell lymphoma

Interferon-alpha (IFN-alpha) therapy is commonly used in the treatment of neoplastic and autoimmune diseases, including cutaneous T cell lymphoma (CTCL). However, the IFN-alpha response is unpredictable, and the IFN-alpha cell targets and pathways are only partially understood. To delineate the molecular mechanisms of IFN-alpha activity, gene expression profiling was performed in a time-course experiment of both IFN-alpha sensitive and IFN-alpha-resistant variants of a CTCL cell line. These experiments revealed that IFN-alpha is responsible for the regulation of hundreds of genes in both variants and predominantly involves genes implicated in signal transduction, cell cycle control, apoptosis, and transcription regulation. Specifically, the IFN-alpha response of tumoral T cells is due to a combination of induction of apoptosis in which TNFSF10 and HSXIAPAF1 may play an important role and cell cycle arrest achieved by downregulation of CDK4 and CCNG2 and upregulation of CDKN2C and tumor suppressor genes (TSGs). Resistance to IFN-alpha appears to be associated with failure to induce IRF1 and IRF7 and deregulation of the apoptotic signals of HSXIAPAF1, TRADD, BAD, and BNIP3. Additionally, cell cycle progression is heralded by upregulation of CDC25A and CDC42. A critical role of NF-kappaB in promoting cell survival in IFN-alpha-resistant cells is indicated by the upregulation of RELB and LTB.

Free fatty acid receptors:structural models and elucidation of ligand binding interactions

BACKGROUND: The free fatty acid receptors (FFAs), including FFA1 (orphan name: GPR40), FFA2 (GPR43) and FFA3 (GPR41) are G protein-coupled receptors (GPCRs) involved in energy and metabolic homeostasis. Understanding the structural basis of ligand binding at FFAs is an essential step toward designing potent and selective small molecule modulators.

RESULTS: We analyse earlier homology models of FFAs in light of the newly published FFA1 crystal structure co-crystallized with TAK-875, an ago-allosteric ligand, focusing on the architecture of the extracellular binding cavity and agonist-receptor interactions. The previous low-resolution homology models of FFAs were helpful in highlighting the location of the ligand binding site and the key residues for ligand anchoring. However, homology models were not accurate in establishing the nature of all ligand-receptor contacts and the precise ligand-binding mode. From analysis of structural models and mutagenesis, it appears that the position of helices 3, 4 and 5 is crucial in ligand docking. The FFA1-based homology models of FFA2 and FFA3 were constructed and used to compare the FFA subtypes. From docking studies we propose an alternative binding mode for orthosteric agonists at FFA1 and FFA2, involving the interhelical space between helices 4 and 5. This binding mode can explain mutagenesis results for residues at positions 4.56 and 5.42. The novel FFAs structural models highlight higher aromaticity of the FFA2 binding cavity and higher hydrophilicity of the FFA3 binding cavity. The role of the residues at the second extracellular loop used in mutagenesis is reanalysed. The third positively-charged residue in the binding cavity of FFAs, located in helix 2, is identified and predicted to coordinate allosteric modulators.

CONCLUSIONS: The novel structural models of FFAs provide information on specific modes of ligand binding at FFA subtypes and new suggestions for mutagenesis and ligand modification, guiding the development of novel orthosteric and allosteric chemical probes to validate the importance of FFAs in metabolic and inflammatory conditions. Using our FFA homology modelling experience, a strategy to model a GPCR, which is phylogenetically distant from GPCRs with the available crystal structures, is discussed.

Ophthalmic epidemiology in Europe: the “European Eye Epidemiology” (E3) consortium

The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 population-based studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170,000 European participants. The aim of the consortium is to promote and sustain collaboration and sharing of data and knowledge in the field of ophthalmic epidemiology in Europe, with particular focus on the harmonization of methods for future research, estimation and projection of frequency and impact of visual outcomes in European populations (including temporal trends and European subregions), identification of risk factors and pathways for eye diseases (lifestyle, vascular and metabolic factors, genetics, epigenetics and biomarkers) and development and validation of prediction models for eye diseases. Coordinating these existing data will allow a detailed study of the risk factors and consequences of eye diseases and visual impairment, including study of international geographical variation which is not possible in individual studies. It is expected that collaborative work on these existing data will provide additional knowledge, despite the fact that the risk factors and the methods for collecting them differ somewhat among the participating studies. Most studies also include biobanks of various biological samples, which will enable identification of biomarkers to detect and predict occurrence and progression of eye diseases. This article outlines the rationale of the consortium, its design and presents a summary of the methodology.