Endogenous ADP-ribosylation of eukaryotic elongation factor 2 and its 32 kDa tryptic fragment.

Eukaryotic elongation factor 2 (eEF-2) can undergo ADP-ribosylation in the absence of diphtheria toxin. The binding of free ADP-ribose and endogenous transferase-dependent ADP-ribosylation were distinct reactions for eEF-2, as indicated by different findings. Incubation of eEF-2 tryptic fragment 32/33 kDa (32F) with NAD was ADP-ribosylated and gave rise to the covalent binding of ADP-ribose to eEF-2. 32F was revealed to be at the C-terminal by Edman degradation sequence analysis. In our study, the elution of 32F from SDS-PAGE was ADP-ribosylated both in the presence and absence of diphtheria toxin. These results suggest that endogenous ADP-ribosylation of 32F might be related to protein synthesis. This modification appears to be important for the cell function.     

N-methyl-D-aspartate antagonists, glutamate release inhibitors, 4-aminopyridine at neuromuscular transmission

GLP-1, an incretin hormone of the enteroinsular axis with insulinotropic and glucagonostatic activity, is secreted after nutrient ingestion. GLP-1 is mainly produced by intestinal L-cells in the lower gastrointestinal tract (GIT); simple carbohydrates are absorbed in the upper GIT and alpha-glucosidase inhibition leads to augmented and prolonged GLP-1 release in normal subjects. In a cross-over study, 100 mg acarbose or placebo was administered simultaneously with 100 g sucrose to 11 hyperglycaemic Type 2 diabetic patients poorly controlled with diet and sulphonylureas. Plasma levels of GLP-1, insulin, C-peptide, glugacon, GIP, glucose and H2-exhalation were measured over 6 h. Differences in the integrated responses over the observation period were evaluated by repeated measurement analysis of variance with fasting values used as covariates. With acarbose, sucrose reached the colon 60-90 min after ingestion as indicated by a significant increment in breath hydrogen exhalation (p = 0.005). After an early GLP-1 increment 15 min after sucrose under both conditions, GLP-1 release was prolonged in the acarbose group (p = 0.001; significant from 210 to 360 min.). Initially (0-150 min), glucose (p = 0.001), insulin (p = 0.001), and GIP (p < 0.001) were suppressed by acarbose, whereas later there were no significant differences. Glucagon levels were higher with acarbose in the last 3 h of the 6 h observation period (p = 0.02). We conclude that in hyperglycaemic Type 2 diabetic patients, ingestion of acarbose with a sucrose load leads to elevated and prolonged GLP-1 release.     

Developing microencapsulated 12‐hydroxystearic acid (HSA) for phase change material use

Phase change materials (PCM) have an increasingly more important role as a thermal energy storage (TES) media. However, leakage problem of PCM causes limitation during their integration in TES systems. Therefore, the encapsulation of PCMs is attracting research interest to extend usage of PCMs in real TES applications in recent years. In this study, hydroxystearic acid (HSA) was encapsulated with polymethyl methacrylate (PMMA) and different PMMA comonomer shells via emulsion polymerization method for the first time in literature. HSA with high melting temperature range (74–78°C) can widen the scope of using PCMs, and the encapsulated form can make it more versatile. The chemical structures, morphologies, and thermophysical properties of capsules were determined by FT‐IR, SEM, DSC, TGA, and thermal infrared camera. Among the produced HSA capsule candidates, PMMA‐HEMA is the most promising with latent heat of 48.5 J/g with melting range of 47 to 85°C. SEM analysis indicated that the capsules have spherical shape with compact surface at nano‐micro (100–440 nm) size range; however, some capsules exhibited agglomeration.     

ADP-ribosylation of serum proteins: evaluation as a potential tumor marker

The low-affinity p75 receptor for nerve growth factor (p75NGFR) has been implicated in mediating neuronal cell death in vitro. A recent in vitro study from our laboratory showed that the death of sensory neurons can be prevented by reducing the levels of p75NGFR with antisense oligonucleotides. To determine if p75NGFR also functions as a death signal in vivo, we have attempted to reduce its expression in peripheral sensory neurons by applying antisense oligonucleotides to the proximal end of the transected sciatic or median and ulnar nerves. We report here that antisense oligonucleotides, when applied to the proximal stump of a transected peripheral nerve, are retrogradely transported and effectively reduce p75NGFR protein levels in sensory neurons located in the dorsal root ganglia. Furthermore, treatment of the proximal nerve stump with antisense p75NGFR oligonucleotides significantly reduced the loss of these axotomized sensory neurons. These findings further support the view that p75NGFR is a death signaling molecule and that it signals death in axotomized neurons in the neonatal sensory nervous system.     

Studies on Sustained release XI: Lipid Granules of Sulfamethizole

The aim of this study was to prepare a sustained release granule of sulfamethizole, employing hydrogenated castor oil (Cutina HR). After the dosage form design was made, different formulations were prepared as granules by the fusing technique. The granules manufactured were analysed with sieves between 0.5 and 1 mm openings. The fractions obtained were tested for dissolution rate for a period of seven hours with fluids of varying pHs with the continuous flow-through cell apparatus.

Upon the kinetic evaluation of dissolution data, it was seen that the target release rates were achieved. The results showed that, the drug release rates increase with increasing amounts of PEG 4000 added to the formulations; up to a certain percentage. No increase beyond this point was noticed.

The drug release rates mostly followed zero-order and modified Hixson-Crowell kinetics.     

The effects of various carbon derivative additives on the thermal properties of paraffin as a phase change material

The storage of thermal energy in phase change materials (PCMs) has found wide applications that enable energy conservation and management. Paraffin is a major PCM with its low cost, wide availability, and relatively high latent heat, yet its low thermal conductivity may become a drawback in high‐power applications. In this study, composites of paraffin were prepared with multiwalled carbon nanotubes and activated carbon by a dispersion technique to overcome these drawbacks. Thermal, chemical, and physical influences of incorporating carbon additives with varying structures in paraffin composites on thermal storage capacity were determined. Results indicated that the thermal conductivities of paraffin‐activated carbon composites (PACC) and paraffin multiwalled carbon nanotube composites (PCNC) were improved by a factor of 39.1 and 34.1%, respectively, compared with the conductivity of pure paraffin. As a bonus, the thermal energy storage capacities of PCNCs were enhanced by 9.6%, whereas this remained unchanged for PACCs. Copyright © 2015 John Wiley & Sons, Ltd.