Drug–drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer

Park, Gab-jin,Bae, Soo Hyeon,Park, Wan-Su,Han, Seunghoon,Park, Min-Ho,Shin, Seok-Ho,Shin, Young G,Yim, Dong-Seok Dove Medical Press 2017 Drug design, development and therapy Vol.11 No.-

<P><B>Purpose</B></P><P>A microdose drug–drug interaction (DDI) study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study.</P><P><B>Patients and methods</B></P><P>Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim) and known perpetrators: fluconazole (inhibitor) and rifampin (inducer). For both studies, the microdose (100 μg, cold compound) and the regular dose (20 mg) of omeprazole were given at days 0 and 1, respectively. On days 2–9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis.</P><P><B>Results</B></P><P>The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only) of maximum concentration (C<SUB>max</SUB>) and area under the curve to the last measurement (AUC<SUB>t</SUB>) of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro) and 2.68 (regular) for C<SUB>max</SUB>, and 4.07 (micro), 4.33 (regular) for AUC<SUB>t</SUB>. For the induction study, they were 0.26 (micro) and 0.21 (regular) for C<SUB>max</SUB>, and 0.16 (micro) and 0.15 (regular) for AUC<SUB>t</SUB>. There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition.</P><P><B>Conclusion</B></P><P>Our results may be used as partial evidence that microdose DDI studies may replace regular-dose studies, or at least be used for DDI-screening purposes.</P>

Optimum Morphology of Mixed-Olivine Mesocrystals for a Li-Ion Battery

Park, Kimin,Kim, Jaewon,Wi, Sungun,Lee, Sangheon,Hwang, Taehyun,Kim, Jaewook,Kang, Joonhyeon,Choi, Joon-Phil,Nam, Seunghoon,Park, Byungwoo American Chemical Society 2018 Inorganic Chemistry Vol.57 No.10

<P>In this present work, we report on the synthesis of micron-sized LiMn<SUB>0.8</SUB>Fe<SUB>0.2</SUB>PO<SUB>4</SUB> (LMFP) mesocrystals via a solvothermal method with varying pH and precursor ratios. The morphologies of resultant LMFP secondary particles are classified into two major classes, flakes and ellipsoids, both of which are featured by the mesocrystalline aggregates where the primary particles constituting LMFP secondary particles are crystallographically aligned. Assessment of the battery performance reveals that the flake-shaped LMFP mesocrystals exhibit a specific capacity and rate capability superior to those of other mesocrystals. The origin of the enhanced electrochemical performance is investigated in terms of primary particle size, pore structure, antisite-defect concentration, and secondary particle shape. It is shown that the shape of the secondary particle has just as much of a significant effect on the battery performance as the crystallite size and antisite defects do. We believe that this work provides a rule of design for electrochemically favorable meso/nanostructures, which is of great potential for improving battery performance by tuning the morphology of particles on multilength scales.</P><P>Micron-sized LiMn<SUB>0.8</SUB>Fe<SUB>0.2</SUB>PO<SUB>4</SUB> mesocrystals having various morphologies were facilely synthesized via a solvothermal method. The origin of the different electrochemical performances of the mesocrystals was investigated in terms of primary particle size, pore structure, antisite-defect concentration, and secondary particle shape. We believe that this work can provide a rule of design for the electrochemically favorable meso/nanostructures, which is of great potential for improving battery performance.</P> [FIG OMISSION]</BR>

Synergistic effect of melatonin on exercise-induced neuronal reconstruction and functional recovery in a spinal cord injury animal model

Park, Kanghui,Lee, Youngjeon,Park, Sookyoung,Lee, Seunghoon,Hong, Yunkyung,kil Lee, Sang–,Hong, Yonggeun Blackwell Publishing Ltd 2010 Journal of pineal research Vol.48 No.3

<P>Abstract: </P><P>Nitric oxide (NO) may aggravate neuronal damage after spinal cord injury (SCI). We hypothesized that NO produced by inducible nitric oxide synthase (iNOS) accelerates secondary damage to spinal tissue, which may be reversed by the neuroprotectant, melatonin. This study investigated the effects of combination therapy with melatonin (10 mg/kg) and exercise (10 m/min) on recovery from SCI caused by contusion. We examined locomotor recovery, iNOS gene expression, autophagic and apoptotic signaling, including Beclin-1, LC3, p53 and IKK&agr; protein expression and histological alterations in the ventral horn of the spinal cord. Melatonin in combination with exercise resulted in significantly increased hindlimb movement (<I>P </I><<I> </I>0.05), a reduced level of iNOS mRNA (<I>P </I><<I> </I>0.05) and more motor neurons in the ventral horn, versus control SCI and SCI plus exercise alone, with no effect on the other signaling molecules examined. This study shows that combined therapy with melatonin and exercise reduces the degree of secondary damage associated with SCI in rats and supports the possible use of melatonin in combination with exercise to reduce the side effects related to exercise-induced fatigue and impairment.</P>

GaN HEMT MMIC Doherty Power Amplifier With High Gain and High PAE

Park, Yunsik,Lee, Juyeon,Jee, Seunghoon,Kim, Seokhyeon,Kim, Cheol Ho,Park, Bonghyuk,Kim, Bumman IEEE 2015 IEEE microwave and wireless components letters Vol.25 No.3

<P>This paper presents an approach to maximize the gain and power-added efficiency (PAE) of a Doherty power amplifier (PA) using a 0.25 <TEX>$\mu$</TEX>m GaN pHEMT. The conventional carrier PA has an input matching for the <TEX>${R}_{\rm OPT}$</TEX> load and does not deliver the 3 dB higher gain with <TEX>${2R}_{\rm OPT}$</TEX> load due to the mismatch and it degrades gain and PAE of the PA. To solve the problem, the input match of the carrier PA is optimized at the back-off power level with the <TEX>${2R}_{\rm OPT}$</TEX> output load, while the input is mismatched at a high power level. A Doherty PA with the concept is designed and implemented using a GaN pHEMT MMIC process at 1.8 GHz. The measured average output power, power-added efficiency and gain are 35.6 dBm, 56.3%, and 18.9 dB for a 10 MHz LTE signal with a 6.5 dB PAPR.</P>

Uranium Solution Assay by L-edge Densitometer

Seunghoon Park,Uk-Ryang Park,Jong-Ho Yoon,Sung-Woo Kwak 한국방사성폐기물학회 2016 한국방사성폐기물학회 학술논문요약집 Vol.2016 No.10

High resolution alpha particle spectrometry through collimation

Park, Seunghoon,Kwak, Sung-Woo,Kang, Han-Byeol Elsevier 2015 Nuclear Instruments & Methods in Physics Research. Vol.784 No.-

<P><B>Abstract</B></P> <P>Alpha particle spectrometry with collimation is a useful method for identifying nuclear materials among various nuclides. A mesh type collimator reduces the low energy tail and broadened energy distribution by cutting off particles with a low incidence angle. The relation between the resolution and the counting efficiency can be investigated by changing a ratio of the mesh hole diameter and the collimator thickness. Through collimation, a target particle can be distinguished by a PIPS<SUP>®</SUP> detector under a mixture of various nuclides.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Alpha particle spectrometry with collimation a useful method for identifying nuclear materials among various radionuclides. </LI> <LI> A collimator cut off alpha particles with low angle emitted from a source. </LI> <LI> We confirm that that a collimator improves the resolution of alpha spectra through both simulation and experiments. </LI> </UL> </P>

Therapeutic physical exercise in neural injury: friend or foe?

Park, Kanghui,Lee, Seunghoon,Hong, Yunkyung,Park, Sookyoung,Choi, Jeonghyun,Chang, Kyu-Tae,Kim, Joo-Heon,Hong, Yonggeun The Society of Physical Therapy Science 2015 JOURNAL OF PHYSICAL THERAPY SCIENCE Vol.27 No.12

<P>[Purpose] The intensity of therapeutic physical exercise is complex and sometimes controversial in patients with neural injuries. This review assessed whether therapeutic physical exercise is beneficial according to the intensity of the physical exercise. [Methods] The authors identified clinically or scientifically relevant articles from PubMed that met the inclusion criteria. [Results] Exercise training can improve body strength and lead to the physiological adaptation of skeletal muscles and the nervous system after neural injuries. Furthermore, neurophysiological and neuropathological studies show differences in the beneficial effects of forced therapeutic exercise in patients with severe or mild neural injuries. Forced exercise alters the distribution of muscle fiber types in patients with neural injuries. Based on several animal studies, forced exercise may promote functional recovery following cerebral ischemia via signaling molecules in ischemic brain regions. [Conclusions] This review describes several types of therapeutic forced exercise and the controversy regarding the therapeutic effects in experimental animals versus humans with neural injuries. This review also provides a therapeutic strategy for physical therapists that grades the intensity of forced exercise according to the level of neural injury.</P>

The effects of ruthenium-oxidation states on Ru dissolution in PtRu thin-film electrodes

Park, Yejun,Lee, Byungjoo,Kim, Chunjoong,Oh, Yuhong,Nam, Seunghoon,Park, Byungwoo Cambridge University Press (Materials Research Soc 2009 Journal of materials research Vol.24 No.9

<P>The effects of ruthenium (Ru)-oxidation states were investigated on Ru dissolution from PtRu thin-film electrodes, with the 200 cycles between 0.4 and 1.05 V (versus normal hydrogen electrode). The Ru-oxidation states of the PtRu thin films were systematically modified by an anodic (oxidation) treatment. The anodic-treated PtRu electrodes, whose methanol-oxidation activity was similar to untreated electrodes before the 200 cycles, showed a remarkable decrease in methanol oxidation after the cycles, because of the Ru dissolution from the PtRu surface. The results suggest that the Ru-oxide species are the origin of Ru dissolution in the PtRu alloy.</P>

Development of a Muscle Rigidity Measurement System for an Early Diagnosis of Parkinson’s disease

Seunghoon Lee,Hyunji Park,Jangwoon Park,Heecheon You 대한인간공학회 2013 대한인간공학회 학술대회논문집 Vol.2013 No.5

Background: Muscle rigidity is one of the basic characteristic of PD and which is defined as an increase in resistance to passive stretch of muscle. In an early stage of PD, clinical assessment of rigidity is commonly performed with the rigidity item in the Unified Parkinson’s Disease Rating Scale (UDPRS). However, the UDPRS is time-consuming and also deficient in reliability and reproducibility due to inter and intra-observer variability. Objective: The purpose of this study is to develop a torque based measurement system of muscle rigidity which can be used in early diagnosis of Parkinson’s disease (PD) in a quantitative manner. Method: To validate the torque based method, human arm was modeled and tested with one healthy male subject by passive flexion of the elbow joint. Torque and angle data in the dynamic phase were used to calculate elastic coefficients in flexion. Results: The present study designed a compact, portable, and precise system based upon a glove type device. Our system is composed of compact force sensor and a gyroscope. Application: A new muscle rigidity measurement system can be used for an early diagnosis of PD in terms of an elastic coefficient of muscle.

The critical warning sign of real-time brainstem auditory evoked potentials during microvascular decompression for hemifacial spasm

Park, Sang-Ku,Joo, Byung-Euk,Lee, Seunghoon,Lee, Jeong-A.,Hwang, Jeong-Ho,Kong, Doo-Sik,Seo, Dae-Won,Park, Kwan,Lee, Hoon-Taek Elsevier 2018 CLINICAL NEUROPHYSIOLOGY - Vol.129 No.5

<P><B>Abstract</B></P> <P><B>Objective</B></P> <P>The aim of this study was to define the critical warning sign of real-time brainstem auditory evoked potential (BAEP) for predicting hearing loss (HL) after microvascular decompression (MVD) for hemifacial spasm (HFS).</P> <P><B>Methods</B></P> <P>Nine hundred and thirty-two patients with HFS who underwent MVD with intraoperative monitoring (IOM) of BAEP were analyzed. We used a 43.9 Hz/s stimulation rate and 400 averaging trials to obtain BAEP. To evaluate HL, pure-tone audiometry and speech discrimination scoring were performed before and one week after surgery. We analyzed the incidence for postoperative HL according to BAEP changes and calculated the diagnostic accuracy of significant warning criteria.</P> <P><B>Results</B></P> <P>Only 11 (1.2%) patients experienced postoperative HL. The group showing permanent loss of wave V showed the largest percentage of postoperative HL (<I>p</I> < 0.001). No patient who experienced only latency prolongation (≥1 ms) had postoperative HL. Loss of wave V and latency prolongation (≥1 ms) with amplitude decrement (≥50%) were highly associated with postoperative HL.</P> <P><B>Conclusions</B></P> <P>Loss of wave V and latency prolongation of 1 ms with amplitude decrement ≥50% were the critical warning signs of BAEP for predicting postoperative HL.</P> <P><B>Significance</B></P> <P>These findings elucidate the critical warning sign of real-time BAEP.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Critical warning sign of real-time BAEP during MVD for hemifacial spasm have been studied. </LI> <LI> Loss of wave V and the significant change of both latency and amplitude are the critical signs. </LI> <LI> Isolated wave V latency prolongation of >1 ms without amplitude loss >50% is not saaociated with postoperative hearing loss. </LI> </UL> </P>