Intracranial Pressure and Experimental Model of Diffuse Brain Injury in Rats

Blaha, Martin,Schwab, Juraj,Vajnerova, Olga,Bednar, Michal,Vajner, Ludek,Michal, Tichy The Korean Neurosurgical Society 2010 Journal of Korean neurosurgical society Vol.47 No.1

Objective: In this study, we present a simple closed head injury model as a two-stage experiment. The height of the weight drop enables gradation of head trauma severity. Methods: The head injury device consists of three parts and there are three adjustable parameters-weight (100-600 g). height of fall (5-100 cm) and elasticity of the springs. Thirty male Wistar rats underwent monitoring of intracranial pressure with and without induction of the head injury. Results: The weight drop from 45 to 100 cm led to immediate seizure activity and early death of the experimental animals. Severe head injury was induced from 40 cm weight drop. There was 50% mortality and all surviving rats had behavioral deterioration. Intracranial pressure was 9.3${\pm}$3.76 mmHg. Moderate head injury was induced from 35 cm, mortality decreased to 20-40%, only half of the animals showed behavioral pathology and intracranial pressure was 7.6${\pm}$3.54 mmHg. Weight drop from 30 cm caused mild head injury without mortality and neurological deterioration. Intracranial pressure was slightly higher compared to sham group- 5.5${\pm}$0.74 mmHg and 2.9${\pm}$0.81 mmHg respectively. Conclusion: This model is an eligible tool to create graded brain injury with stepwise intracranial pressure elevation.

Theory of the presidential system of government with regard to some remarks on the case of the Republic of Korea

Blaha, Petr Hankuk University of Foreign Studies. Graduate Sch 2000 Journal of international studies Vol.1 No.2

Robust Control of Permanent Magnet Synchronous Motor

Petr Blaha,Pavel Vaclavek 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

The aim of this paper is to present design of robust current controller, its validation in the environment of Matlab Simulink and its verification on a real motor using rapid prototyping system dSpace 1103. The worst case scenario in current generating part of permanent magnet synchronous motor is considered for controller synthesis. The current controller is designed using μ synthesis so as to reach defined degree of robust performance for defined variations of motor parameters. The controller design takes into account time delays caused with discretization and with finite computational time of the control algorithm. The designed controller was checked if it meets proposed requirements in the whole speed operating range. Paper also shows dependency of controller reduced order on sensitivity function template from the perspective of reached control performance.

Insights into Base Selectivity from the 1.8 Å Resolution Structure of an RB69 DNA Polymerase Ternary Complex

Wang, Mina,Xia, Shuangluo,Blaha, Gregor,Steitz, Thomas A.,Konigsberg, William H.,Wang, Jimin American Chemical Society 2011 Biochemistry Vol.50 No.4

<P/><P>Bacteriophage RB69 DNA polymerase (RB69 pol) has served as a model for investigating how B family polymerases achieve a high level of fidelity during DNA replication. We report here the structure of an RB69 pol ternary complex at 1.8 Å resolution, extending the resolution from our previously reported structure at 2.6 Å [Franklin, M. C., et al. (2001) <I>Cell 105</I>, 657−667]. In the structure presented here, a network of five highly ordered, buried water molecules can be seen to interact with the N3 and O2 atoms in the minor groove of the DNA duplex. This structure reveals how the formation of the closed ternary complex eliminates two ordered water molecules, which are responsible for a kink in helix P in the apo structure. In addition, three pairs of polar−nonpolar interactions have been observed between (i) the Cα hydrogen of G568 and the N3 atom of the dG templating base, (ii) the O5′ and C5 atoms of the incoming dCTP, and (iii) the OH group of S565 and the aromatic face of the dG templating base. These interactions are optimized in the dehydrated environment that envelops Watson−Crick nascent base pairs and serve to enhance base selectivity in wild-type RB69 pol.</P>

Investigation of the reduction process of dopamine using paired pulse voltammetry

Kim, D. H.,Oh, Y.,Shin, H.,Blaha, C. D.,Bennet, K. E.,Lee, K. H.,Kim, I. Y.,Jang, D. P. Elsevier Science B.V., Amsterdam. 2014 Journal of Electroanalytical Chemistry Vol.717 No.-

A baseline drift detrending technique for fast scan cyclic voltammetry

DeWaele, Mark,Oh, Yoonbae,Park, Cheonho,Kang, Yu Min,Shin, Hojin,Blaha, Charles D.,Bennet, Kevin E.,Kim, In Young,Lee, Kendall H.,Jang, Dong Pyo The Royal Society of Chemistry 2017 The Analyst Vol.142 No.22

<P>Fast scan cyclic voltammetry (FSCV) has been commonly used to measure extracellular neurotransmitter concentrations in the brain. Due to the unstable nature of the background currents inherent in FSCV measurements, analysis of FSCV data is limited to very short amounts of time using traditional background subtraction. In this paper, we propose the use of a zero-phase high pass filter (HPF) as the means to remove the background drift. Instead of the traditional method of low pass filtering across voltammograms to increase the signal to noise ratio, a HPF with a low cutoff frequency was applied to the temporal dataset at each voltage point to remove the background drift. As a result, the HPF utilizing cutoff frequencies between 0.001 Hz and 0.01 Hz could be effectively used to a set of FSCV data for removing the drifting patterns while preserving the temporal kinetics of the phasic dopamine response recorded <I>in vivo</I>. In addition, compared to a drift removal method using principal component analysis, this was found to be significantly more effective in reducing the drift (unpaired <I>t</I>-test <I>p</I> < 0.0001, <I>t</I> = 10.88) when applied to data collected from Tris buffer over 24 hours although a drift removal method using principal component analysis also showed the effective background drift reduction. The HPF was also applied to 5 hours of FSCV <I>in vivo</I> data. Electrically evoked dopamine peaks, observed in the nucleus accumbens, were clearly visible even without background subtraction. This technique provides a new, simple, and yet robust, approach to analyse FSCV data with an unstable background.</P>

Multi-waveform fast-scan cyclic voltammetry mapping of adsorption/desorption kinetics of biogenic amines and their metabolites

Kim, Do Hyoung,Oh, Yoonbae,Shin, Hojin,Park, Cheonho,Blaha, Charles D.,Bennet, Kevin E.,Kim, In Young,Lee, Kendall H.,Jang, Dong Pyo The Royal Society of Chemistry 2018 Analytical methods Vol.10 No.24

<P>Fast-scan cyclic voltammetry (FSCV) is an effective method for investigating electro-active neurochemical species. In recent years, FSCV has been used to measure electro-active neurotransmitters in a variety of neuroscience studies. We previously reported on the use of paired-pulse voltammetry (PPV) that enables FSCV to differentiate various analytes and minimize confounding factors by taking advantage of the adsorption characteristics of the analyte on carbon fiber microelectrodes. In spite of a number of studies regarding adsorption/desorption characteristics of neurotransmitters, the difference in adsorption/desorption properties among neurotransmitters has yet to be fully explored. To calculate adsorption/desorption constants for neurotransmitters, we propose the use of multi-waveform FSCV (M-FSCV), which consists of ten triangular waveforms in a single scan. Within the multiple waveforms, the voltammetric response of dopamine decayed exponentially because of the decreased adsorption time period. The decay pattern was mathematically described using adsorption/desorption characteristics and two additional initial points: an exponential decay constant (<I>K</I>) and an initial quantity (<I>A</I>), which were extracted from the decay equation. Using this method, we were able to quantify the decay constant (<I>K</I>-map) and an initial quantity (<I>A</I>-map) color plot in addition to a conventional pseudo color plot. M-FSCV was evaluated with two biogenic amine groups (catecholamines and indolamines) to characterize their inherent adsorption/desorption constants. As a result, the <I>A</I>-map showed a high correlation with concentration and the <I>K</I>-map for each group to be significantly differentiated. These results demonstrate that M-FSCV has the potential to be a useful technique for acquiring additional adsorption/desorption information regarding neurotransmitters.</P>

Sensitive and Selective Measurement of Serotonin <i>in Vivo</i> Using Fast Cyclic Square-Wave Voltammetry

Shin, Hojin,Oh, Yoonbae,Park, Cheonho,Kang, Yumin,Cho, Hyun U.,Blaha, Charles D.,Bennet, Kevin E.,Heien, Michael L.,Kim, In Young,Lee, Kendall H.,Jang, Dong Pyo American Chemical Society 2020 ANALYTICAL CHEMISTRY - Vol.92 No.1

<P>Although N-shaped fast scan cyclic voltammetry (N-FSCV) is well-established as an electroanalytical method to measure extracellular serotonin concentrations <I>in vivo</I>, it is in need of improvement in both sensitivity and selectivity. Based on our previous studies using fast cyclic square-wave voltammetry (FCSWV) for <I>in vivo</I> dopamine measurements, we have modified this technique to optimize the detection of serotonin <I>in vivo</I>. A series of large amplitude square-shaped potentials was superimposed onto an N-shaped waveform to provide cycling through multiple redox reactions within the N-shaped waveform to enhance the sensitivity and selectivity to serotonin measurement when combined with a two-dimensional voltammogram. N-Shaped fast cyclic square-wave voltammetry (N-FCSWV) showed significantly higher sensitivity to serotonin compared to conventional N-FSCV. In addition, N-FCSWV showed better performance than conventional N-shaped FSCV in differentiating serotonin from its major interferents, dopamine and 5-hydroxyindoleascetic acid (5-HIAA). It was also confirmed that the large amplitude of the square waveform did not influence local neuronal activity, and it could monitor electrical stimulation evoked phasic release of serotonin in the rat substantia nigra pars reticulata (SNr) before and after systemic injection of escitalopram (ESCIT, 10 mg/kg i.p.), a serotonin selective reuptake inhibitor.</P> [FIG OMISSION]</BR>

Deep Brain Stimulation: Technology at the Cutting Edge

Rahul S. Shah,Su-Youne Chang,민훈기,조장희,Charles D. Blaha,Kendall H. Lee 대한신경과학회 2010 Journal of Clinical Neurology Vol.6 No.4

Deep brain stimulation (DBS) surgery has been performed in over 75,000 people worldwide, and has been shown to be an effective treatment for Parkinson’s disease, tremor, dystonia, epilepsy,depression, Tourette’s syndrome, and obsessive compulsive disorder. We review current and emerging evidence for the role of DBS in the management of a range of neurological and psychiatric conditions, and discuss the technical and practical aspects of performing DBS surgery. In the future, evolution of DBS technology may depend on several key areas, including better scientific understanding of its underlying mechanism of action, advances in high-spatial resolution imaging and development of novel electrophysiological and neurotransmitter microsensor systems. Such developments could form the basis of an intelligent closed-loop DBS system with feedback-guided neuromodulation to optimize both electrode placement and therapeutic efficacy.

Fast Cyclic Square-Wave Voltammetry To Enhance Neurotransmitter Selectivity and Sensitivity

Park, Cheonho,Oh, Yoonbae,Shin, Hojin,Kim, Jaekyung,Kang, Yumin,Sim, Jeongeun,Cho, Hyun U.,Lee, Han Kyu,Jung, Sung Jun,Blaha, Charles D.,Bennet, Kevin E.,Heien, Michael L.,Lee, Kendall H.,Kim, In Youn American Chemical Society 2018 ANALYTICAL CHEMISTRY - Vol.90 No.22

<P>Although fast-scan cyclic voltammetry (FSCV) has been widely used for in vivo neurochemical detection, the sensitivity and selectivity of the technique can be further improved. In this study, we develop fast cyclic square-wave voltammetry (FCSWV) as a novel voltammetric technique that combines large-amplitude cyclic square-wave voltammetry (CSWV) with background subtraction. A large-amplitude, square-shaped potential was applied to induce cycling through multiple redox reactions within a square pulse to increase sensitivity and selectivity when combined with a two-dimensional voltammogram. As a result, FCSWV was significantly more sensitive than FSCV (<I>n</I> = 5 electrodes, two-way ANOVA, <I>p</I> = 0.0002). In addition, FCSWV could differentiate dopamine from other catecholamines (e.g., epinephrine and norepinephrine) and serotonin better than conventional FSCV. With the confirmation that FCSWV did not influence local neuronal activity, despite the large amplitude of the square waveform, it could monitor electrically induced phasic changes in dopamine release in rat striatum before and after injecting nomifensine, a dopamine reuptake inhibitor.</P> [FIG OMISSION]</BR>