Self-complementary AAV Virus (scAAV) Safe and Long-term Gene Transfer in the Trabecular Meshwork of Living Rats and Monkeys

AAV vectors produce stable transgene expression and elicit low immune response in many tissues. AAVs have been the vectors of choice for gene therapy for the eye, in particular the retina. scAAVs are modified AAVs that bypass the required second-strand DNA synthesis to achieve transcription of the transgene. The goal was to investigate the ability of AAV vectors to induce long-term, safe delivery of transgenes to the trabecular meshwork of living animals

A comparative study of enzyme immobilization strategies for multi-walled carbon nanotube glucose biosensors

This work addresses the comparison of different strategies for improving biosensor performance using nanomaterials. Glucose biosensors based on commonly applied enzyme immobilization approaches, including sol-gel encapsulation approaches and glutaraldehyde cross-linking strategies, were studied in the presence and absence of multi-walled carbon nanotubes (MWNTs). Although direct comparison of design parameters such as linear range and sensitivity is intuitive, this comparison alone is not an accurate indicator of biosensor efficacy, due to the wide range of electrodes and nanomaterials available for use in current biosensor designs. We proposed a comparative protocol which considers both the active area available for transduction following nanomaterial deposition and the sensitivity. Based on the protocol, when no nanomaterials were involved, TEOS/GOx biosensors exhibited the highest efficacy, followed by BSA/GA/GOx and TMOS/GOx biosensors. A novel biosensor containing carboxylated MWNTs modified with glucose oxidase and an overlying TMOS layer demonstrated optimum efficacy in terms of enhanced current density (18.3 +/- 0.5 mu A mM(-1) cm(-2)), linear range (0.0037-12 mM), detection limit (3.7 mu M), coefficient of variation (2%), response time (less than 8 s), and stability/selectivity/reproducibility. H(2)O(2) response tests demonstrated that the most possible reason for the performance enhancement was an increased enzyme loading. This design is an excellent platform for versatile biosensing applications

Oscillatory glucose flux in INS 1 pancreatic beta cells: A self-referencing microbiosensor study

Signaling and insulin secretion in beta cells have been reported to demonstrate oscillatory modes, with abnormal oscillations associated with type 2 diabetes. We investigated cellular glucose influx in beta cells with a self-referencing (SR) microbiosensor based on nanomaterials with enhanced performance. Dose-response analyses with glucose and metabolic inhibition studies were used to study oscillatory patterns and transporter kinetics. For the first time, we report a stable and regular oscillatory uptake of glucose (averaged period 2.9 +/- 0.6 min), which corresponds well with an oscillator model. This oscillatory behavior is part of the feedback control pathway involving oxygen, cytosolic Ca(2+)/ATP, and insulin secretion (periodicity approximately 3 min). Glucose stimulation experiments show that the net Michaelis-Menten constant (6.1 +/- 1.5 mM) is in between GLUT2 and GLUT9. Phloretin inhibition experiments show an EC(50) value of 28 +/- 1.6 mu M phloretin for class I GLUT proteins and a concentration of 40 +/- 0.6 mu M phloretin caused maximum inhibition with residual nonoscillating flux, suggesting that the transporters not inhibited by phloretin are likely responsible for the remaining nonoscillatory uptake, and that impaired uptake via GLUT2 may be the cause of the oscillation loss in type 2 diabetes. Transporter studies using the SR microbiosensor will contribute to diabetes research and therapy development by exploring the nature of oscillatory transport mechanisms. (C) 2010 Elsevier Inc. All rights reserved

Electrochemical glutamate biosensing with nanocube and nanosphere augmented single-walled carbon nanotube networks: a comparative study

We describe two hybrid nanomaterial biosensor platforms, based on networks of single-walled carbon nanotubes (SWCNTs) enhanced with Pd nanocubes and Pt nanospheres and grown in situ from a porous anodic alumina (PAA) template. These nanocube and nanosphere SWCNT networks are converted into glutamate biosensors by immobilizing the enzyme glutamate oxidase (cross-linked with gluteraldehyde) onto the electrode surface. The Pt nanosphere/SWCNT biosensor outperformed the Pd nanocube/SWCNT biosensor and previously reported similar nanomaterial-based biosensors by amperometrically monitoring glutamate concentrations with a wide linear sensing range (50 nM to 1.6 mM) and a small detection limit (4.6 nM, 3 sigma). These results combined with the biosensor fabrication scheme (in situ growth of SWCNTs, electrodeposition of metal nanoparticles, and facile enzyme immobilization protocol) create a biosensor that can potentially be scaled for integration into a wide range of applications including the treatment of neurological disorders

Daily spinal mechanical loading as a risk factor for acute non-specific low back pain: a case–control study using the 24-Hour Schedule

A case–control study was conducted to assess the daily loading of the spine as a risk factor for acute non-specific low back pain (acute LBP). Acute LBP is a benign, self-limiting disease, with a recovery rate of 80–90% within 6 weeks irrespective of the treatment type. Unfortunately, recurrence rates are high. Therefore, prevention of acute LBP could be beneficial. The 24-Hour Schedule (24HS) is a questionnaire developed to quantify physical spinal loading, which is regarded as a potential and modifiable risk factor for acute and recurrent low back pain. A total of 100 cases with acute LBP and 100 controls from a primary care setting were included. Cases and controls completed questionnaires regarding acute LBP status and potential risk factors. Trained examiners blinded to subjects’ disease status (acute LBP or not) assessed spinal loading using the 24HS. The mean difference of 24HS sum-scores between groups was statistically significant (P < 0.0001). After multivariate regression analysis, previous episode(s), the 24HS and the Nottingham Health Profile were associated with the presence of acute LBP. High 24HS scores, indicating longer and more intensive spinal loading in flexed position, are strongly associated with acute LBP

Modulation of immune responses by targeting CD169/Siglec-1 with the glycan ligand

A fundamental role in the plant-bacterium interaction for Gram-negative phytopathogenic bacteria is played by membrane constituents, such as proteins, lipopoly- or lipooligosaccharides (LPS, LOS) and Capsule Polysaccharides (CPS). In the frame of the understanding the molecular basis of plant bacterium interaction, the Gram-negative bacterium Agrobacterium vitis was selected in this study. It is a phytopathogenic member of the Rhizobiaceae family and it induces the crown gall disease selectively on grapevines (Vitis vinifera). A. vitis wild type strain F2/5, and its mutant in the quorum sensing gene ΔaviR, were studied. The wild type produces biosurfactants; it is considered a model to study surface motility, and it causes necrosis on grapevine roots and HR (Hypersensitive Response) on tobacco. Conversely, the mutant does not show any surface motility and does not produce any surfactant material; additionally, it induces neither necrosis on grape, nor HR on tobacco. Therefore, the two strains were analyzed to shed some light on the QS regulation of LOS structure and the consequent variation, if any, on HR response. LOS from both strains were isolated and characterized: the two LOS structures maintained several common features and differed for few others. With regards to the common patterns, firstly: the Lipid A region was not phosphorylated at C4 of the non reducing glucosamine but glycosylated by an uronic acid (GalA) unit, secondly: a third Kdo and the rare Dha (3-deoxy-lyxo-2-heptulosaric acid) moiety was present. Importantly, the third Kdo and the Dha residues were substituted by rhamnose in a not stoichiometric fashion, giving four different oligosaccharide species. The proportions among these four species, is the key difference between the LOSs from both the two bacteria. LOS from both strains and Lipid A from wild type A. vitis are now examined for their HR potential in tobacco leaves and grapevine roots