Fabrication of a Self-Curling Cuff with a Soft, Ionically Conducting Neural Interface.

Direct current (DC) has the potential not only to excite but also to inhibit neurons. This property of DC stimulus has been used for generating peripheral nerve blocks. One translational challenge of DC-based neuromodulation technologies, especially for pain suppression, is that the commercially available cuff electrodes have metal-tissue interfaces that are incapable of delivering DC safely. Passing DC through any metal-tissue interface generates harmful electrochemical products which can damage the target nerve. To address this issue, we present a fabrication process for making self-curling silicone cuffs with paper/agar based, ionically conducting neural interface. We fabricate monopolar as well as bipolar cuffs and demonstrate that the electrode impedances can be easily controlled by modulating the paper/agar channel dimensions. Further, we perform in-vivo implantation of these electrodes on a rat sciatic nerve to qualitatively validate the self-curling action.

Renal cells exposed to cadmium in vitro and in vivo: normalizing gene expression data.

Cadmium (Cd) is a toxic metal with a long half-life in biological systems. This half-life is partly as a result of metallothioneins (MTs), metal-binding proteins with a high affinity for Cd. The high retention properties of the kidneys reside in proximal tubular cells that possess transport mechanisms for Cd-MT uptake, ultimately leading to more Cd accumulation. Researchers have studied MT-metal interactions using various techniques including quantitative real-time PCR (qPCR), an efficient tool for quantifying gene expression. Often a poor choice of reference genes, which is represented by their instability and condition dependency, leads to inefficient normalization of gene expression data and misinterpretations. This study demonstrates the importance of an efficient normalization strategy in toxicological research. A selection of stable reference genes was proposed in order to acquire reliable and reproducible gene quantification under metal stress using MT expression as an example. Moreover, in vitro and in vivo setups were compared to identify the influence of toxicological compounds in function of the experimental design. This study shows that glyceraldehyde-3-phosphate dehydrogenase (Gapdh), tyrosine monooxygenase/tryptophan5-monooxygenase activation-protein, zeta polypeptide (Ywhaz) and beta-actin (Actb) are the most stable reference genes in a kidney proximal tubular cell line exposed to moderate and high Cd concentrations, applied as CdCl2 . A slightly different sequence in reference gene stability was found in renal cells isolated from rats in vivo exposed to Cd. It was further shown that three reference genes are required for efficient normalization in this experimental setup. This study demonstrates the importance of an efficient normalization strategy in toxicological research.

A proof-of-concept study to assess the putative dose response to topical corticosteroid in persistent allergic rhinitis using adenosine monophosphate challenge.

INTRODUCTION: The aim of this proof-of-concept study was to assess whether nasal adenosine monophosphate (AMP) challenge may be used to quantify dose response to topical fluticasone propionate (FP) in persistent allergic rhinitis (PER). METHODS: Eligible subjects with PER entered a randomized double-blind crossover study of 2 weeks of intranasal FP at 100 microg or 400 microg daily, with a 2-week placebo washout period before each randomized treatment. Measurements after each washout or treatment comprised: peak nasal inspiratory flow (PNIF) response to nasal AMP (the primary outcome), domiciliary PNIF, the mini rhinoconjunctivitis quality of life questionnaire (miniRQLQ), symptom scores, nasal nitric oxide levels and overnight urinary cortisol:creatinine ratios. RESULTS: Thirteen patients completed per protocol. Maximal PNIF response to AMP was attenuated 0.9% (95% confidence interval -7.1 to 9.0, P=NS) by FP 100 microg, and 12.9% (4.8-20.9, P=0.009) by FP 400 microg. The 400-100 microg difference was 12.0% U (2.6-21.3, P=0.049). None of the other outcomes were responsive enough to detect any significant treatment effects. The standardized response means to FP 400 microg were 81% for AMP challenge, 54% for domiciliary PNIF, 53% for miniRQLQ, 24% for symptom scores and 18% for nasal nitric oxide. No adrenal suppression was detected at either dose. CONCLUSION: FP exhibited dose-related suppression of nasal airway hyperresponsiveness to AMP challenge, but without associated detectable adrenal suppression at the higher dose. Moreover, the AMP response demonstrated the highest signal to noise ratio compared with other outcome measures in PER.

Paradoxical effects of trichostatin A: inhibition of NF-Y-associated histone acetyltransferase activity, phosphorylation of hGCN5 and downregulation of cyclin A and B1 mRNA.

Trichostatin A (TSA), an inhibitor of histone deacetylase (HDAC), is widely used to study the role of histone acetylation in gene expression, since genes that use histone acetylation as a means of regulating expression may be up regulated when TSA is added. In this study, however, we show that TSA has an unexpected paradoxical effect leading to inhibition of NF-Y-associated histone acetyl transferase (HAT) activity and phosphorylation of the HAT, hGCN5. TSA treatment of cells resulted in diminished levels of NF-Y-associated HAT activity without changes in NF-Y(A) amount. hGCN5 is one of the HATs known to associate with NF-Y. The association of hGCN5 with NF-Y was not altered by TSA treatment. The enzymatic activity of hGCN5 is known to be inhibited by phosphorylation. TSA treatment of Hela cells resulted in phosphorylation of hGCN5. Exposure of the NF-Y immunoprecipitates from TSA-treated cells to a phosphatase resulted in enhanced HAT activity. We have also shown that the mRNA levels of several genes, cyclin B1 and cyclin A, are downregulated by TSA; these effects do not require protein synthesis and the downregulation of cyclin B1 by TSA occurs through transcription. These results suggest that TSA can have contradictory effects, on one hand stimulating HAT activity in general by inhibition of HDACs, but also resulting in inhibition of NF-Y-associated HAT activity and phosphorylation of hGCN5.

Effect of pyridoxine and insulin administration on brain glutamate dehydrogenase activity and blood glucose control in streptozotocin-induced diabetic rats.

Blood glucose level and kinetic parameters of glutamate dehydrogenase (GDH) were measured in the cerebellum, brain stem and cerebral cortex of control, insulin treated, pyridoxine treated, pyridoxine and insulin treated and untreated streptozotocin-diabetic rats. The combined administration of insulin and pyridoxine was found to be better in controlling the hyperglycaemia. Insulin with pyridoxine treatment brought back the increased maximal velocity of GDH during diabetes to control state. Also, there was an increase in Michaelis-Menten constant. These results suggest that pyridoxine and insulin together serve a better control for diabetes.

Purification and characterization of a wound-inducible cell wall cationic peroxidase from carrot roots.

We have isolated a novel cell wall, cationic peroxidase (pI > 9.3) from roots of the carrot plant, Daucus carota. The purified isozyme, referred to as CP > 9.3, has a molecular mass of 45 kilodaltons and an Reinheitzahl value of 2.3. Amino-acid composition analysis and N-terminal sequencing have been performed with CP > 9.3. The N-terminal sequence shows no homology to any sequence in the protein and nucleic acid data banks. CP > 9.3 activity is induced by wounding in carrot leaves and petioles; this activity is also present in carrot roots but is unaltered by wounding. Enhanced CP > 9.3 activity is seen at 12 hr post-wounding and continues for at least 60 hr in leaves and petioles. Based on studies using cycloheximide, early activation of CP > 9.3 is not due to de novo protein synthesis, but rather to enzyme activation. Temperature and pH optima for CP > 9.3 using guaiacol as a substrate have been determined to be 32 degrees C and 4.9.

Elevated serum glycosaminoglycans with hypomagnesemia in patients with coronary artery disease & thrombotic stroke.

Elevated levels of serum glycosaminoglycans (GAG), associated with hypomagnesemia were observed in patients of proven CAD and thrombotic stroke in Kerala. Serum lipid profile was normal in the majority of these patients, indicating that elevated serum GAG may be an even more reliable indicator of atherosclerosis than elevated serum total cholesterol or LDL cholesterol. Autopsy samples of carotid artery and aorta which had atheroma showed significantly higher GAG when compared to samples which showed no atheroma. Serum Mg levels were significantly lower in CAD and thrombotic stroke patients as compared to controls. Mg deficiency may be one of the factors involved in the increased level of GAG.

Anti diabetic activity of amrithadi churnam.

Amrithadi Churnam - a compound ayurvedic preparation made up of Tinospora cordifolia, Salacia prenoides, Curcuma longa, Tribulus terrestris and Emblica Officinalis was screened for its antidiabetic activity. From the studies it could be established that Amrithadi churnam at a dose level of 100mg/kg b.w. was the optimum dose in alloxan diabetic rats. No toxic effects were observed as evidenced by the study of liver enzymes and blood haematoerit. An extra pancreatic role of the drug cannot be rulled out, since it (100 mg/kg b.w) produced significant decrease in blood sugar level in alloxan diabetic rats.