Evaluation of N (epsilon)-(3-formyl-3,4-dehydropiperidino)lysine as a novel biomarker for the severity of diabetic retinopathy.

AIMS/HYPOTHESIS: Recent studies suggest that oxidative stress should be monitored alongside HbA(1c) to identify subgroups of diabetic patients at high risk of initiation or progression of retinopathy. The acrolein-derived advanced lipoxidation end-product (ALE), [Formula: see text]-(3-formyl-3,4-dehydropiperidino)lysine (FDP-lysine), is a useful biomarker that reflects the cumulative burden of oxidative stress over long periods of time. The purpose of the present study was to investigate whether serum and haemoglobin levels of FDP-lysine are associated with the severity of diabetic retinopathy in type 1 and type 2 diabetic patients.

METHODS: Serum and haemoglobin levels of FDP-lysine were measured by competitive ELISA in 59 type 1 and 76 type 2 diabetic patients with no retinopathy, non-proliferative retinopathy or proliferative retinopathy (mean age [+/-SEM] 54.3 +/- 1.3 years), and in 47 non-diabetic control individuals (mean age 51.9 +/- 2.1 years).

RESULTS: Serum and haemoglobin levels of FDP-lysine were significantly increased in diabetic patients compared with control individuals (p = 0.04 and p = 0.002, respectively). However, no significant association was found between levels of serum FDP-lysine and the severity of diabetic retinopathy (p = 0.97). In contrast, increased haemoglobin FDP-lysine levels were observed in patients with proliferative retinopathy compared with patients without retinopathy and with non-proliferative retinopathy (p = 0.04). The relationship of FDP-lysine with proliferative retinopathy was unaltered after adjustment for HbA(1c), or other clinical parameters.

CONCLUSIONS/INTERPRETATION: Our data suggest that haemoglobin FDP-lysine may provide a useful risk marker for the development of proliferative diabetic retinopathy independently of HbA(1c), and that elevated intracellular ALE formation may be involved in the pathogenesis of this sight-threatening complication of diabetes.

Accelerated degradation behaviour of poly(epsilon-caprolactone) via melt blending with poly(aspartic acid-co-lactide) (PAL)

Poly(epsilon-caprolactone) (PCL) has many favourable attributes for tissue engineering scaffold applications. A major drawback, however, is its slow degradation rate, typically greater than 3 years. In this study PCL was melt blended with a small percentage of poly(aspartic acid-co-lactide) (PAL) and the degradation behaviour was evaluated in phosphate buffer solution (PBS) at 37 degrees C. The addition of PAL was found to significantly enhance the degradation profile of PCL. Subsequent degradation behaviour was investigated in terms of the polymer's mechanical properties, Molecular weight (M-w), mass changes and thermal characteristics. The results indicate that the addition of PAL accelerates the degradation of PCL, with 20% mass loss recorded after just 7 months in vitro for samples containing 8 wt% PAL. The corresponding pure PCL samples exhibited no mass loss over the same time period. In vitro assessment of PCL and PCL/PAL composites in tissue Culture medium in the absence of cells revealed stable pH readings with time. SEM studies of cell/biomaterial interactions demonstrated biocompatibility of C3H10T1/2 cells with PCL and PCL/PAL composites at all concentrations of PAL additive. (C) 2008 Elsevier Ltd. All rights reserved.

Carriage of apoE epsilon 4 lowers the age of onset of Alzheimer's Disease in Northern Ireland

Alzheimer's disease is the most common neurodegenerative disorder affecting those in mid to late adult life. Carriage of an apolipoprotein E (apoE) epsilon 4 allele has been shown to be associated with an increased risk of developing AD in numerous studies involving populations of various races and ethnic backgrounds. It has also been suggested that carriage of this allele reduces the age of onset of AD. To investigate this, we carried out a genetic association study utilising 108 sporadic late-onset AD patients and age, sex and ethnically-matched controls from Northern Ireland. Findings of this study verified the risk of AD associated with carriage of the apoE epsilon 4 allele in a dose-dependent manner (p

Proteomics Identification of Azaspiracid Toxin Biomarkers in Blue Mussels, Mytilus edulis

Azaspiracids are a class of recently discovered algae-derived shellfish toxins. Their distribution globally is on the increase with mussels being most widely implicated in azaspiracid-related food poisoning events. Evidence that these toxins were bound to proteins in contaminated mussels has been shown recently. In the present study characterization of these proteins in blue mussels, Mytilus edulis, was achieved using a range of advanced proteomics tools. Four proteins present only in the hepatopancreas of toxin-contaminated mussels sharing identity or homology with cathepsin D, superoxide dismutase, glutathione S-transferase Pi, and a bacterial flagellar protein have been characterized. Several of the proteins are known to be involved in self-defense mechanisms against xenobiotics or up-regulated in the presence of carcinogenic agents. These findings would suggest that azaspiracids should now be considered and evaluated as potential tumorigenic compounds. The presence of a bacterial protein only in contaminated mussels was an unexpected finding and requires further investigation. The proteins identified in this study should assist with development of urgently required processes for the rapid depuration of azaspiracid-contaminated shellfish. Moreover they may serve as early warning indicators of shellfish exposed to this family of toxins. Molecular & Cellular Proteomics 8: 1811-1822, 2009.

A rapid optical immunoassay for the screening of T-2 and HT-2 toxin in cereals and maize-based baby food

A rapid surface plasmon resonance (SPR) screening assay has been developed for the combined detection of T-2 and HT-2 toxins in naturally contaminated cereals using a sensor chip coated with an HT-2 toxin derivative and a monoclonal antibody. The antibody raised against HT-2 displayed high cross-reactivity with T-2 toxin while there was no cross-reaction observed with other commonly occurring trichothecenes. A simple extraction procedure using 40% methanol was applied to baby food, breakfast cereal, and wheat samples prior to biosensor analysis. Limits of detection (LOD) for each matrix were determined as 25 mu g kg(-1) for baby food and breakfast cereal and 26 mu g kg(-1) for wheat. Intra-assay precision (n = 6) was calculated for each matrix. The results were expressed as the relative standard deviation and determined as 2.8% (100 mu g kg(-1)) and 1.8% (200 mu g kg(-1)) in breakfast cereal, 4.6% (50 mu g kg(-1)) and 3.6% (100 mu g kg(-1)) in wheat and 0.97% (25 mu g kg(-1)) and 6.3% (50 mu g kg(-1)) in baby food. Between run precision (n = 3) performed at the same levels yielded relative standard deviations of 6.7% and 3.9% for breakfast cereals, 3.3% and 1.6% for wheat and 6.8% and 0.08% for baby food, respectively. (C) 2010 Elsevier B.V. All rights reserved.

Remote, subsurface detection of the algal toxin domoic acid onboard the Environmental Sample Processor: Assay development and field trials

The ability to detect harmful algal bloom (HAB) species and their toxins in real- or near real-time is a critical need for researchers studying HAB/toxin dynamics, as well as for coastal resource managers charged with monitoring bloom populations in order to mitigate their wide ranging impacts. The Environmental Sample Processor (ESP), a robotic electromechanical/fluidic system, was developed for the autonomous, subsurface application of molecular diagnostic tests and has successfully detected several HAB species using DNA probe arrays during field deployments. Since toxin production and thus the potential for public health and ecosystem effects varies considerably in natural phytoplankton populations, the concurrent detection of HAB species and their toxins onboard the ESP is essential. We describe herein the development of methods for extracting the algal toxin domoic acid (DA) from Pseudonitzschia cells (extraction efficiency >90%) and testing of samples using a competitive ELISA onboard the ESP. The assay detection limit is in the low ng/mL range (in extract), which corresponds to low ng/L levels of DA in seawater for a 0.5 L sample volume acquired by the ESP. We also report the first in situ detection of both a HAB organism (i.e., Pseudo-nitzschia) and its toxin, domoic acid, via the sequential (within 2-3 h) conduct of species- and toxin-specific assays during ESP deployments in Monterey Bay, CA, USA. Efforts are now underway to further refine the assay and conduct additional calibration exercises with the aim of obtaining more reliable, accurate estimates of bloom toxicity and thus their potential impacts. Published by Elsevier B.V.

Optical Nonlocalities and Additional Waves in Epsilon-Near-Zero Metamaterials

We analyze the optical properties of plasmonic nanorod metamaterials in the epsilon-near-zero regime and show, both theoretically and experimentally, that the performance of these composites is strongly affected by nonlocal response of the effective permittivity tensor. We provide the evidence of interference between main and additional waves propagating in the room-temperature nanorod metamaterials and develop an analytical description of this phenomenon. Additional waves are present in the majority of low-loss epsilon-near-zero structures and should be explicitly considered when designing applications of epsilon-near-zero composites, as they represent a separate communication channel.

Enantioselective formal total synthesis of the Dendrobatidae frog toxin, (+)-pumiliotoxin B, via O-directed alkyne free radical hydrostannation

Herein we describe our application of the O-directed free radical hydrostannation of disubstituted alkyl-acetylenes (with Ph3SnH and Et3B) to the (+)-pumiliotoxin B total synthesis problem. Specifically, we report on the use of this method in the synthesis of the Overman alkyne 8, and thereby demonstrate the great utility of this process in a complex natural product total synthesis setting for the very first time. We also report here on a new, stereocontrolled, and highly practical enantioselective pathway to Overman's pyrrolidine epoxide partner 9 for 8, which overcomes the previous requirement for use of preparative HPLC to separate the 1:1 mixture of diastereomeric epoxides that was obtained in the original synthesis of 9.

Paralytic shellfish poisoning (PSP) toxin binders for optical biosensor technology: problems and possibilities for the future: a review

This review examines the developments in optical biosensor technology, which uses the phenomenon of surface plasmon resonance, for the detection of paralytic shellfish poisoning (PSP) toxins. Optical biosensor technology measures the competitive biomolecular interaction of a specific biological recognition element or binder with a target toxin immobilised onto a sensor chip surface against toxin in a sample. Different binders such as receptors and antibodies previously employed in functional and immunological assays have been assessed. Highlighted are the difficulties in detecting this range of low molecular weight toxins, with analogues differing at four chemical substitution sites, using a single binder. The complications that arise with the toxicity factors of each toxin relative to the parent compound, saxitoxin, for the measurement of total toxicity relative to the mouse bioassay are also considered. For antibodies, the cross-reactivity profile does not always correlate to toxic potency, but rather to the toxin structure to which it was produced. Restrictions and availability of the toxins makes alternative chemical strategies for the synthesis of protein conjugate derivatives for antibody production a difficult task. However, when two antibodies with different cross-reactivity profiles are employed, with a toxin chip surface generic to both antibodies, it was demonstrated that the cross-reactivity profile of each could be combined into a single-assay format. Difficulties with receptors for optical biosensor analysis of low molecular weight compounds are discussed, as are the potential of alternative non-antibody-based binders for future assay development in this area.

A European perspective on progress in moving away from the mouse bioassay for marine-toxin analysis

This review considers the ethical and technical problems currently associated with employing mouse bioassays for marine-toxin analysis and the challenges and the difficulties that alternative methods must overcome before being deemed applicable for implementation into a regulatory monitoring regime. We discuss proposed alternative methods, classified as functional, immunological and analytical, for well-established European toxins as well as emerging toxins in European waters, highlighting their advantages and disadvantages. We also consider emerging tools and technologies for future toxin analysis.

Effect of Inhibitor Compounds on N-epsilon-(Carboxymethyl)lysine (CML) and N-epsilon-(Carboxyethyl)lysine (CEL) Formation in Model Foods

The possible adverse effects on health of diet-derived advanced glycation endproducts (AGES) and advanced lipoxidation endproducts (ALES) is of current interest. This study had the objective of determining the effects of the addition of AGE/ALE inhibitors and different types of sugar and cooking oil on N-epsilon-(carboxymethyl)lysine (CML) and N-epsilon-(carboxyethyl)lysine (CEL) formation in model foods (sponge cakes). The cake baked using glucose produced the highest level of CML (2.07 +/- 0.24 mmol/mol lysine), whereas the cake baked using fructose produced the highest concentration of CEL (25.1 +/- 0.15 mmol/mol lysine). There were no significant differences between CML concentrations formed in the cakes prepared using different types of cooking oil, but significant differences (P