Gas-filled protein nanostructures as cavitation nuclei for molecule-specific sonodynamic therapy.

Sonodynamic therapy (SDT) is a promising alternative for cancer therapy, understood to exert cytotoxicity through cavitation and subsequent production of large amounts of reactive oxygen species (ROS). Gas-filled protein nanostructures (gas vesicles or GVs) produced by cyanobacteria have a hollow structure similar to microbubbles and have demonstrated comparable enhancement of ultrasound imaging contrast. We thus hypothesized that GVs may act as stable nuclei for inertial cavitation to enhance SDT with improved enhanced permeability and retention (EPR) effects due to their nanometer scale. The function of GVs to mediate cavitation, ROS production, and cell-targeted toxicity under SDT was determined. In solution, we found that GVs successfully increased cavitation and enhanced ROS production in a dose- and time-dependent manner. Then, GV surfaces were modified (FGVs) to specifically target CD44+ cells and accumulate preferentially at the tumor site. In vitro sonodynamic therapy (SDT) showed ROS production and tumor cell toxicity substantially elevated in the presence of FGVs, and the addition of FGVs was found to enhance cavitation and subsequently inhibit tumor growth and exert greater damage to tumors under SDT in vivo. Our results thus demonstrate that FGVs can function as stable, nanosized, nuclei for spatially accurate and cell-targeted SDT. STATEMENT OF SIGNIFICANCE: The initiation of inertial cavitation is critical for ROS generation and subsequent cellular toxicity in SDT. Thus, precise control of the occurrence of cavitation is a key factor in increasing SDT's therapeutic efficacy. We explored nanometer-sized gas vesicles (GVs) as a new class of cavitation nuclei for molecule-specific sonodynamic therapy. Our results showed that GV-mediated SDT treatment enabled targeted disruption of specific cells expressing a known surface marker within the area of insonation, providing a spatially specific and targeted SDT treatment.

Cinobufagin Is a Selective Anti-Cancer Agent against Tumors with EGFR Amplification and PTEN Deletion.

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor, and almost half of the patients carrying EGFR-driven tumor with PTEN deficiency are resistant to EGFR-targeted therapy. EGFR amplification and/or mutation is reported in various epithelial tumors. This series of studies aimed to identify a potent compound against EGFR-driven tumor. We screened a chemical library containing over 600 individual compounds purified from Traditional Chinese Medicine against GBM cells with EGFR amplification and found that cinobufagin, the major active ingredient of Chansu, inhibited the proliferation of EGFR amplified GBM cells and PTEN deficiency enhanced its anti-proliferation effects. Cinobufagin also strongly inhibited the proliferation of carcinoma cell lines with wild-type or mutant EGFR expression. In contrast, the compound only weakly inhibited the proliferation of cancer cells with low or without EGFR expression. Cinobufagin blocked EGFR phosphorylation and its downstream signaling, which additionally induced apoptosis and cytotoxicity in EGFR amplified cancer cells. In vivo, cinobufagin blocked EGFR signaling, inhibited cell proliferation, and elicited apoptosis, thereby suppressing tumor growth in both subcutaneous and intracranial U87MG-EGFR xenograft mouse models and increasing the median survival of nude mice bearing intracranial U87MG-EGFR tumors. Cinobufagin is a potential therapeutic agent for treating malignant glioma and other human cancers expressing EGFR.

Cyclability evaluation on Si based Negative Electrode in Lithium ion Battery by Graphite Phase Evolution: an operando X-ray diffraction study.

Artificial graphite (FSN) additive is employed as internal structural label for projecting cyclability of Si material native electrode in a mass ratio of Si/FSN = 1.0 in Li ion battery (LIB). Results of operando X-ray diffraction analysis on Si-FSN negative electrode in LIB demonstrate that one can evaluate the lithiation and delithiation affinity of active material by referring phase transition delay of graphite as affected by experimental splits in a formation process of LIB. We prove that a thin layer of surface amorphous structure and residual lattice strain are formed in Si by high energy ball-milling treatment. Those manipulations improve Li intercalation kinetics and thus enabling a capacity fading of less than 10% (from 1860 to 1650 mAhg-1) for Si negative electrode in 50 cycles. Of utmost importance, this study discloses a robust assessment for revealing mechanism on amorphous and strain related silicide formation and predicting cyclability of negative electrode by quantitative phase evolution rate of FSN additive in LIB.

Functional integration of newly generated neurons into striatum after cerebral ischemia in the adult rat brain.

BACKGROUND AND PURPOSE: Ischemic injury can induce neurogenesis in the striatum. Those newborn neurons can express glutamic acid decarboxylase and choline acetyltransferase, markers of GABAergic and cholinergic neurons, respectively. The present study investigated whether these GABAergic and cholinergic new neurons could differentiate into functional cells. METHODS: Retrovirus containing the EGFP gene was used to label dividing cells in striatal slices prepared from adult rat brains after middle cerebral artery occlusion. EGFP-targeted immunostaining and immunoelectron microscopy were performed to detect whether newborn neurons could anatomically form neuronal polarity and synapses with pre-existent neurons. Patch clamp recording on acute striatal slices of brains at 6 to 8 weeks after middle cerebral artery occlusion was used to determine whether the newborn neurons could display functional electrophysiological properties. RESULTS: EGFP-expressing (EGFP(+)) signals could be detected mainly in the cell body in the first 2 weeks. From the fourth to thirteenth weeks after their birth, EGFP(+) neurons gradually formed neuronal polarity and showed a time-dependent increase in dendrite length and branch formation. EGFP(+) cells were copositive for NeuN and glutamic acid decarboxylase (EGFP(+)-NeuN(+)-GAD(67)(+)), MAP-2, and choline acetyltransferase (EGFP(+)-MAP-2(+)-ChAT(+)). They also expressed phosphorylated synapsin I (EGFP(+)-p-SYN(+)) and showed typical synaptic structures comprising dendrites and spines. Both GABAergic and cholinergic newborn neurons could fire action potentials and received excitatory and inhibitory synaptic inputs because they displayed spontaneous postsynaptic currents in picrotoxin- and CNQX-inhibited manners. CONCLUSIONS: Ischemia-induced newly formed striatal GABAergic and cholinergic neurons could become functionally integrated into neural networks in the brain of adult rats after stroke.

Mechanochemical synthesis of Si/Cu3Si-based composite as negative electrode materials for lithium ion battery.

Mechanochemical synthesis of Si/Cu3Si-based composite as negative electrode materials for lithium ion battery is investigated. Results indicate that CuO is decomposed and alloyed with Si forming amorphous Cu-Si solid solution due to high energy impacting during high energy mechanical milling (HEMM). Upon carbonization at 800 °C, heating energy induces Cu3Si to crystallize in nanocrystalline/amorphous Si-rich matrix enhancing composite rigidity and conductivity. In addition, residual carbon formed on outside surface of composite powder as a buff space further alleviates volume change upon lithiation/delithiation. Thus, coin cell made of C-coated Si/Cu3Si-based composite as negative electrode (active materials loading, 2.3 mg cm-2) conducted at 100 mA g-1 performs the initial charge capacity of 1812 mAh g-1 (4.08 mAh cm-2) columbic efficiency of 83.7% and retained charge capacity of 1470 mAh g-1 (3.31 mAh cm-2) at the end of the 100th cycle, opening a promised window as negative electrode materials for lithium ion batteries.

CSmiRTar: Condition-Specific microRNA targets database.

MicroRNAs (miRNAs) are functional RNA molecules which play important roles in the post-transcriptional regulation. miRNAs regulate their target genes by repressing translation or inducing degradation of the target genes' mRNAs. Many databases have been constructed to provide computationally predicted miRNA targets. However, they cannot provide the miRNA targets expressed in a specific tissue and related to a specific disease at the same time. Moreover, they cannot provide the common targets of multiple miRNAs and the common miRNAs of multiple genes at the same time. To solve these two problems, we construct a database called CSmiRTar (Condition-Specific miRNA Targets). CSmiRTar collects computationally predicted targets of 2588 human miRNAs and 1945 mouse miRNAs from four most widely used miRNA target prediction databases (miRDB, TargetScan, microRNA.org and DIANA-microT) and implements functional filters which allows users to search (i) a miRNA's targets expressed in a specific tissue or/and related to a specific disease, (ii) multiple miRNAs' common targets expressed in a specific tissue or/and related to a specific disease, (iii) a gene's miRNAs related to a specific disease, and (iv) multiple genes' common miRNAs related to a specific disease. We believe that CSmiRTar will be a useful database for biologists to study the molecular mechanisms of post-transcriptional regulation in human or mouse. CSmiRTar is available at http://cosbi.ee.ncku.edu.tw/CSmiRTar/ or http://cosbi4.ee.ncku.edu.tw/CSmiRTar/.

Saffman-Taylor-like instability in a narrow gap induced by dielectric barrier discharge.

This work is inspired by the expansion of the plasma bubble in a narrow gap reported by Chu and Lee [Phys. Rev. Lett. 107, 225001 (2011)]. We report the unstable phenomena of the plasma-liquid interface with different curvature in a Hele-Shaw cell. Dielectric barrier discharge is produced in the cell at atmospheric pressure which is partially filled with silicone oil. We show that the Saffman-Taylor-like instability is observed on the bubble-type, channel-type, and drop-type interfaces. The Schlieren observation of the plasma-drop interaction reveals that there is a vapor layer around the drop and the particle image velocimetry shows the liquid flow inside the drop. We propose that the thermal Marangoni effect induced by the plasma heating is responsible for the unstable phenomena of the plasma-liquid interaction. The fluctuation of the interface is shown consistently with the Saffman-Taylor instability modified by the temperature-dependent velocity and surface tension.

Spinal antinociceptive effect of agmatine and tentative analysis of involved receptors: study in an electrophysiological model of rats.

The present study was designed to evaluate the antinociceptive effect of agmatine and the receptors involved at the spinal level by using an experimental model in which agmatine was intrathecally (i.t.) administered while the changes of nociceptively-evoked discharges in thalamic parafascicular (PF) neurons were monitored in anesthetized Wistar rats. The results showed that: (1) i.t. agmatine dose-dependently suppressed the nociceptive discharges of PF neurons induced by the tail pinch; (2) i.t. yohimbine did not block the agmatine-induced suppressive effect of nociceptive discharges in these neurons; and (3) the agmatine-induced suppression could be blocked significantly by i.t. idazoxan. The results suggest that agmatine suppresses the transmission of nociceptive inputs at the spinal level mainly through the activation of imidazoline receptors other than alpha(2)-adrenoceptors.

A force plate measurement system to assess hindlimb weight support of spinal cord injured rats.

This paper describes a force plate system for quantitative measurement of the hindlimb weight support of rats. The system is built around a microcontroller and uses strain gauges to measure individually the weight applied by each limb and also the general hindquarters of the rat. The sum of weights on the individual force plates adds up to the total weight of the rat. Mathematical comparison of the weights of the different force plates allows calculation of the weight percentage of the hindquarters (W%HQ=(hindquarters weight/total weight)x100%). When hindlimb impairment is high, the W%HQ is high and vise versa, allowing hindlimb weight support to be evaluated by the W%HQ. An actual laboratory embodiment is demonstrated and real experiments are performed on spinal cord damaged rats. W%HQ results are compared with Basso, Beattie, Bresnahan (BBB) locomotor behavioural test results on the same rats at approximately the same time. When a rat is placed in the correct position of the test chamber, the user can use a local keypad/LCD display (standalone mode) or the PC keyboard/display to control the system and access the current data. Comparing our results with those of the BBB method confirms the proposed hardware and W%HQ metric represent very well the recovery of a rat after spinal cord injury. Medical investigators report that under actual use, the presented system is stable, accurate and easy to use. Additional advantages of the presented force plate system include stand-alone capability, non-dependence on subjective human judgement and quantitative results.

Melatonin inhibits outward delayed rectifier potassium currents in hippocampal CA1 pyramidal neuron via intracellular indole-related domains.

In the present study, we investigated the effect of melatonin on the outward delayed rectifier potassium currents (IK) in CA1 pyramidal neurons of rat hippocampal slices using patch-clamp technique in whole-cell configuration. In a concentration-dependent manner, melatonin caused a reduction of IK with a half-maximal inhibitory concentration (IC50) of 3.75 mm. The inhibitory effect had rapid onset and was readily reversible. Melatonin shifted steady-state inactivation of IK in hyperpolarizing direction but did not alter its steady-state activation. Neither luzindole, an MT1/MT2 receptor antagonist, nor prazosin, an MT3 receptor antagonist, blocked melatonin-induced current reduction. The results indicate that melatonin-induced IK inhibition was not via activation of its own membrane receptors. 5-Hydroxytryptamine (5-HT), a melatonin precursor and an agonist of serotonin receptors, when it was given in pipette internal solution but not bath solution, produced a similar inhibitory effect to that of melatonin. Moreover, indole, a major component of melatonin, reversibly and dose dependently inhibited IK with an IC50 of 3.44 mm. Present results suggest that melatonin inhibits IK in hippocampal CA1 pyramidal neurons probably through its interaction with the intracellular indole-related domains of potassium channels.