Locomotor sensitization to cocaine is associated with distinct pattern of glutamate receptor trafficking to the postsynaptic density in prefrontal cortex: Early versus late withdrawal effects

Glutamatergic neurotransmission plays an important role in the behavioral and molecular plasticity observed in cocaine mediated locomotor sensitization. Recent studies show that glutamatergic signaling is regulated by receptor trafficking, synaptic localization, and association with scaffolding proteins. The trafficking of the glutamate receptors was investigated in the dorsal and ventral prefrontal cortex at 1 and 21 days after repeated cocaine administration which produced robust locomotor sensitization. A subcellular fractionation technique was used to isolate the cellular synaptosomal fraction containing the postsynaptic density. At early withdrawal, the prefrontal cortex displayed a reduction in the synaptosomal content of the AMPA and NMDA receptor subunits. In contrast, after extended withdrawal, there was a significant increase in the trafficking of the receptors into the synaptosomal compartment. These changes were accompanied by corresponding trafficking of the postsynaptic glutamatergic scaffolding proteins. Thus, enhanced trafficking of glutamate receptors from cytosolic to synaptosomal compartment is associated with prolonged withdrawal from repeated exposure to cocaine and may have functional consequences for the synaptic and behavioral plasticity.     

Comparing the effects of root surface scaling with ultrasound instruments and Er,Cr:YSGG laser

There are several studies done to show the comparability of laser scaling and root planing with routine methods. The most suitable wavelengths for such an application are reported as 2,940 and 2,780 nm. The superficial interactions of the current wavelength with root surface is investigated in this study to compare the crater and crack formation during the procedures between ultrasound and Er,Cr:yttrium-scandium-gallium garnet (YSGG; 2,780 nm) laser-treated teeth. Thirty human teeth with calculus on their root surface, which were extracted because of the severe periodontitis, were selected for this interventional in vitro study. Calculus area were divided into two equal parts: One of them was prepared for Er,Cr:YSGG (Biolase, Waterlase, USA) laser irradiation and the other one for ultrasound treatment (Dentsply cavitron, DENTSPLY International, USA). The Er,Cr:YSGG laser was specified as follows: pulse energy = 50 mJ, power = 1 W, wavelength = 2,780 nm, pulse repetition rate = 20 pulse per seconds, tip length = 6 mm, and tip diameter = 600 microm. Nineteen of the laser samples (95%) and eight of ultrasound ones (40%) out of 20 samples in each group had craters showing a statistical significant difference (p < 0.001). The number and depth of these craters are also evaluated. Thirteen samples of the laser cases (65%) and all samples of the ultrasound group showed cracks with significant differences (p = 0.008). In addition, the number and width of cracks in both groups are reported. As a general conclusion, the laser-treated samples show more craters but less cracks.     

Transition from congress abstract to full publication for clinical trials presented at laser meetings

The present study aims to identify (1) what proportion of abstracts of clinical trials presented at The American Society for Laser Medicine and Surgery (ASLMS) annual meetings are published as full reports, (2) time to publication, and (3) factors that may predict the publication of research in peer-reviewed journals. Two investigators independently hand-searched all abstracts of the ASLMS meetings to identify all reports of clinical trials. Details of sample size, the country of origin, topic of research, type of presentation, type of laser, direction of outcome, and statistical significance were recorded for each abstract. To determine the full publication status of each study, The Cochrane Central Register of Controlled Trials, PubMed, and EMBASE was searched. A total of 198 abstracts were identified. Of these, 87 abstracts (44%) have been fully published. The average time from presentation at the meeting to full publication was 57 months (95% confidence interval = 52-61), and the estimated rate of abstracts published at 1, 2, and 4 years was 15, 30, and 38%, respectively. There is significant tendency for being fully published in high-power laser studies, with USA as country of origin, and orally presented. Our findings supports this opinion that conference abstracts can be an important source for systematic reviews and failure to identify trials presented in congresses might threaten the validity of systematic reviews.     

Effect of Nano Silica on Setting Time and Physical Properties of Mineral Trioxide Aggregate

IntroductionMineral trioxide aggregate (MTA) has been widely used in all fields of endodontics. One of the major drawbacks of this material is the long setting time. MTA is primarily composed of type 1 Portland cement and bismuth oxide. In cement, nanoscale SiO₂ behaves as a filler to improve microstructure and to accelerate hydration process. The aforementioned reaction is also expected in MTA because of the same structure. Thus, the aim of this study was to evaluate the effect of addition of nano-SiO₂ to MTA on the setting time and its physical properties.MethodsTwo concentrations (8% and 10%) of nano-SiO₂ were added to the white MTA powder. After mixing with water, the setting time, compressive strength, and flexural strength were investigated and compared with pure MTA.ResultsWith the addition of 8% and 10% of nano-SiO₂ to the MTA, the setting time of both mixtures decreased significantly (P < .05). However, the compressive strength (after 1 day and 1 week) and flexural strength increased; this was not significant (P > .05). There was no significant difference between MTA mixed with 8% and 10% nano-SiO₂ in setting time, compressive strength, and flexural strength (P > .05).ConclusionsThe addition of 8% and 10% of nano-SiO₂ to MTA accelerated the hydration process, reduced the setting time, and had no adverse effect on the compressive and flexural strength of MTA.