• The Korean Journal of Pain
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• v.31 no.3
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• pp.155-173
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• 2018

Chronic postsurgical pain (CPSP) is an unwanted adverse event in any operation. It leads to functional limitations and psychological trauma for patients, and leaves the operative team with feelings of failure and humiliation. Therefore, it is crucial that preventive strategies for CPSP are considered in high-risk operations. Various techniques have been implemented to reduce the risk with variable success. Identifying the risk factors for each patient and applying a timely preventive strategy may help patients avoid the distress of chronic pain. The preventive strategies include modification of the surgical technique, good pain control throughout the perioperative period, and preoperative psychological intervention focusing on the psychosocial and cognitive risk factors. Appropriate management of CPSP patients is also necessary to reduce their suffering. CPSP usually has a neuropathic pain component; therefore, the current recommendations are based on data on chronic neuropathic pain. Hence, voltage-dependent calcium channel antagonists, antidepressants, topical lidocaine and topical capsaicin are the main pharmacological treatments. Paracetamol, NSAIDs and weak opioids can be used according to symptom severity, but strong opioids should be used with great caution and are not recommended. Other drugs that may be helpful are ketamine, clonidine, and intravenous lidocaine infusion. For patients with failed pharmacological treatment, consideration should be given to pain interventions; examples include transcutaneous electrical nerve stimulation, botulinum toxin injections, pulsed radiofrequency, nerve blocks, nerve ablation, neuromodulation and surgical management. Physical therapy, cognitive behavioral therapy and lifestyle modifications are also useful for relieving the pain and distress experienced by CPSP patients.

• Journal of Korea Multimedia Society
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• v.20 no.10
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• pp.1678-1688
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• 2017

Infiltration is one of detrimental problems occurring in nursing or medical settings. Early detection of infiltration is essential to minimize the risk of injury from infiltration. To perform a preliminary study on the point of care and automated infiltration detection system, bioelectrical impedance was investigated using bioelectrical impedance analyzer. We would like to report experimental results that allow impedance parameters to effectively distinguish infiltration. Electrodes were attached to both sides of the transparent dressing on the fusion site where IV solution was being infused. Then, impedance parameters before and after infiltration were measured as a function of time and frequency. The experimental results are as follows. After infiltration was intentionally induced by puncturing the vein wall with a needle, the resistance gradually decreased with time. That is, when an alternating current having a frequency of 20 kHz was applied to the electrodes, the resistance gradually decreased with time, reflecting the accumulation of IV solution in the extracellular fluid since the current could not pass through the cell membrane. Impedance parameters and equivalent circuit model for human cell were used to examine the mechanism of current flow before and after infiltration, which could be used for early detection of infiltration.

• The Korean Journal of Pain
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• v.29 no.1
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• pp.40-47
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• 2016

Background: Neuropathic pain, including paresthesia/dysesthesia in the lower extremities, always develops and remains for at least one month, to variable degrees, after percutaneous endoscopic lumbar discectomy (PELD). The recently discovered dual analgesic mechanisms of action, similar to those of antidepressants and anticonvulsants, enable nefopam (NFP) to treat neuropathic pain. This study was performed to determine whether NFP might reduce the neuropathic pain component of postoperative pain. Methods: Eighty patients, who underwent PELD due to herniated nucleus pulposus (HNP) at L4-L5, were randomly divided into two equal groups, one receiving NFP (with a mixture of morphine and ketorolac) and the other normal saline (NS) with the same mixture. The number of bolus infusions and the infused volume for 3 days were compared in both groups. The adverse reactions (ADRs) in both groups were recorded and compared. The neuropathic pain symptom inventory (NPSI) score was compared in both groups on postoperative days 1, 3, 7, 30, 60, and 90. Results: The mean attempted number of bolus infusions, and effective infused bolus volume for 3 days was lower in the NFP group for 3 days. The most commonly reported ADRs were nausea, dizziness, and somnolence, in order of frequency in the NFP group. The median NPSI score, and all 5 median sub-scores in the NFP group, were significantly lower than that of the NS group until postoperative day 30. Conclusions: NFP significantly reduced the neuropathic pain component, including paresthesia/dysesthesia until 1 month after PELD. The common ADRs were nausea, dizziness, somnolence, and ataxia.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.587-595
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• 2003

The aim of this study was to investigate trazodone's effect on vasorelaxation and blood pressure lowering and to examine its underlying mechanism of action in isolated thoracic aorta and anesthesized rats. Precontracted aortic rings with high KCl were relaxed with trazodone, at concentrations of $50{\mu}M$ or greater. However, precontracted rings with phenylephrine (PE) were relaxed with trazodone, at concentrations of $0.03{\mu}M$ or greater, in a concentration-dependent manner. These relaxant effects of trazodone on endothelium intact rat aortic rings were significantly greater than those on denuded rings. The trazodone-induced relaxations were suppressed by nitric oxide synthase (NOS) inhibitors, N(G)-nitro-L-arginine (L-NNA) and N(omega)-nitro-L-arginine methyl ester (L-NAME), guanylate cyclase inhibitors, methylene blue and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a $Ca^{2+}$-activated $K^+$ channel blocker, tetrabutylammonium (TBA), a $Ca^{2+}$ channel blocker, nifedipine, $Na^+$ channel blockers, lidocaine and procaine, and removal of extracellular $Na^+$, but not by aminoguanidine, 2-nitro-4-carboxyphenyl-n, n-diphenylcarbamate (NCDC), indomethacin, glibenclamide and clotrimazole. In vivo, infusion of trazodone elicited significant decrease in arterial blood pressure. Trazodone-induced decrease in blood pressure was markedly inhibited by pretreatment of intravenous injection of saponin, L-NNA, methylene blue, TBA, lidocaine or nifedipine. These findings suggest that the endothelium-dependent relaxation and decrease in blood pressure induced by trazodone is mediated by release of NO from the endothelium, activation of TBA-sensitive $Ca^{2+}$-activated $K^+$ channels or inhibition of $Ca^{2+}$ entry through voltage-gated channel.

• Biomolecules & Therapeutics
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• v.24 no.2
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• pp.199-205
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• 2016

This study aimed to investigate the in vivo relevance of P-glycoprotein (P-gp) in the pharmacokinetics and adverse effect of phenformin. To investigate the involvement of P-gp in the transport of phenformin, a bi-directional transport of phenformin was carried out in LLC-PK1 cells overexpressing P-gp, LLC-PK1-Pgp. Basal to apical transport of phenformin was 3.9-fold greater than apical to basal transport and became saturated with increasing phenformin concentration ($2-75{\mu}M$) in LLC-PK1-Pgp, suggesting the involvement of P-gp in phenformin transport. Intrinsic clearance mediated by P-gp was $1.9{\mu}L/min$ while passive diffusion clearance was $0.31{\mu}L/min$. Thus, P-gp contributed more to phenformin transport than passive diffusion. To investigate the contribution of P-gp on the pharmacokinetics and adverse effect of phenformin, the effects of verapamil, a P-gp inhibitor, on the pharmacokinetics of phenformin were also examined in rats. The plasma concentrations of phenformin were increased following oral administration of phenformin and intravenous verapamil infusion compared with those administerd phenformin alone. Pharmacokinetic parameters such as $C_{max}$ and AUC of phenformin increased and CL/F and Vss/F decreased as a consequence of verapamil treatment. These results suggested that P-gp blockade by verapamil may decrease the phenformin disposition and increase plasma phenformin concentrations. P-gp inhibition by verapamil treatment also increased plasma lactate concentration, which is a crucial adverse event of phenformin. In conclusion, P-gp may play an important role in phenformin transport process and, therefore, contribute to the modulation of pharmacokinetics of phenformin and onset of plasma lactate level.

• Biomolecules & Therapeutics
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• v.25 no.4
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• pp.383-389
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• 2017

Dexmedetomidine is an ${\alpha}2$-adrenergic receptor agonist that exhibits a protective effect on ischemia-reperfusion injury of the heart, kidney, and other organs. In the present study, we examined the neuroprotective action and potential mechanisms of dexmedetomidine against ischemia-reperfusion induced cerebral injury. Transient focal cerebral ischemia-reperfusion injury was induced in Sprague-Dawley rats by middle cerebral artery occlusion. After the ischemic insult, animals then received intravenous dexmedetomidine of $1{\mu}g/kg$ load dose, followed by $0.05{\mu}g/kg/min$ infusion for 2 h. After 24 h of reperfusion, neurological function, brain edema, and the morphology of the hippocampal CA1 region were evaluated. The levels and mRNA expressions of interleukin-$1{\beta}$, interleukin-6 and tumor nevrosis factor-${\alpha}$ as well as the protein expression of inducible nitric oxide synthase, cyclooxygenase-2, nuclear factor-${\kappa}Bp65$, inhibitor of ${\kappa}B{\alpha}$ and phosphorylated of ${\kappa}B{\alpha}$ in hippocampus were assessed. We found that dexmedetomidine reduced focal cerebral ischemia-reperfusion injury in rats by inhibiting the expression and release of inflammatory cytokines and mediators. Inhibition of the nuclear factor-${\kappa}B$ pathway may be a mechanism underlying the neuroprotective action of dexmedetomidine against focal cerebral I/R injury.

• Journal of Trauma and Injury
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• v.19 no.1
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• pp.41-46
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• 2006

Purpose: Hypovolemia is not uncommon among trauma patients in the emergency department (ED). Successful resuscitation of a hypovolemic patient often requires rapid intravenous administration of massive amounts of fluid. A rapid fluid infuser is used in the ED for this purpose, there have been no studies of their clinical uses and effectiveness. We studied clinical experience with a rapid fluid infuser at an urban university hospital in Seoul, Korea. Methods: We reviewed the medical records of 38 patients admitted to the ED with a history of application of a rapid fluid infuser from January 2004 to July 2005. Adult trauma patients older than 15 years of age were included in this study. Clinical data on the patients and the volume of fluid used to achieve a stable blood pressure were extracted from their medical records. Results: The total number of adult trauma patients with a history of application of a rapid fluid infuser from January 2004 to July 2005 in the ED was 16. The mean systolic blood pressure for deciding to apply the rapid fluid infuser was $74.9{\pm}12.7mmHg$. The mean time and volume used to achieve a stable blood pressure were 40.4 min and$2947.3{\pm}1339.2ml$, respectively. In all patients, the amount of fluid infused before using the rapid fluid infuser was between 500 ml and 10,000 ml, compared to 1,000 ml and 6,200 ml with the rapid fluid infuser. The mean amount of fluid per min. via the rapid fluid infuser was 85.5 ml. Vital signs were stabilized in 11 patients, 6 of the 11 were discharged alive. Conclusion: The mean amount of fluid delivered per min. via the rapid fluid infuser was much less than expected; thus, there should be clinical guidelines on volume resuscitation with a rapid fluid infuser in the ED. In the future, prospective, multicenter, clinical-data collection is needed for a more sophisticated study.

• Radiation Oncology Journal
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• v.29 no.4
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• pp.252-259
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• 2011

Purpose: To evaluate retrospectively the survival outcome, patterns of failure, and complications in patients treated with postoperative chemoradiotherapy (CRT) in advanced gastric cancer. Materials and Methods: Between January 2000 and December 2006, 80 patients with advanced gastric cancer who received postoperative concurrent CRT were included. Pathological staging was IB-II in 9%, IIIA in 38%, IIIB in 33%, and IV in 21%. Radiotherapy consisted of 45 Gy of radiation. Concurrent chemotherapy consisted of a continuous intravenous infusion of 5-fluorouracil and leucovorin on the first 4 days and last 3 days of radiotherapy. Results: The median follow-up period was 48 months (range, 3 to 83 months). The 5-year overall survival, disease-free survival, and locoregional recurrence-free survivals were 62%, 59%, and 80%, respectively. In the multivariate analysis, significant factors for disease-free survival were T stage (hazard ratio [HR], 0.278; P = 0.038), lymph node dissection extent (HR, 0.201; P = 0.002). and maintenance oral chemotherapy (HR, 2.964; P = 0.004). Locoregional recurrence and distant metastasis occurred in 5 (6%) and 18 (23%) patients, respectively. Mixed failure occurred in 10 (16%) patients. Grade 3 leukopenia and thrombocytopenia were observed in 4 (5%) and one (1%) patient, respectively. Grade 3 nausea and vomiting developed in 8 (10%) patients. Intestinal obstruction developed in one (1%). Conclusion: The survival outcome of the postoperative CRT in advanced gastric cancer was similar to those reported previously. Our postoperative CRT regimen seems to be a safe and effective method, reducing locoregional failure without severe treatment toxicity in advanced gastric cancer patients.

• Tuberculosis and Respiratory Diseases
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• v.57 no.6
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• pp.579-583
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• 2004

Actinomycosis is an indolent infectious disease characterized by pyogenic response and necrosis, followed by intense fibrosis. The main forms of human actinomycosis are cervicofacial, pulmonary, and abdominopelvic type. Pulmonary actinomycosis accounts for 15% to 20% of total cases and unfortunately, clinical manifestations and radiologic findings are nonspecific. Small pleural effusion or empyema may develop in advanced disease but massive empyema is infrequent and rarely reported. We report a case of huge empyema caused by pulmonary actinomycosis in a 55 year-old man, presented with one-month history of productive cough and fever. The CT scan revealed a huge cavity with air-fluid level occupying the left hemithorax. Empyema caused by actinomycosis was confirmed microscopically by demonstration of sulfur granules in empyema sac through thracotomy. Decortication and surgical resection of empyema sac and destructed lung was accomplished and followed by intravenous infusion of penicillin G.

• Biomedical Science Letters
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• v.11 no.3
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• pp.355-363
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• 2005

This study aimed to investigate the cerebroprotective effect of vascular endothelial growth factor (VEGF) on permanent focal cerebral ischemia in Sprague-Dawley rats. Right middle cerebral artery (MCA) was occluded for 6 and 24 hours by an intraluminal monofilament technique. An open cranial window was made on the right parietal bone for determination of continuous changes in regional cerebral blood flow (rCBF) by laser-Doppler flowmetry. The infarct size was morphometrically determined using the 2,3,5-triphenyltetrazolium chloride technique. Brain edema was determined by measuring brain water content. In normal rats, rCBF was significantly increased by intravenous infusion of VEGF for 10 minutes. The VEGF-induced increase in rCBF was significantly inhibited by pretreatment with suramin, a heparin-binding growth factor inhibitor as well as $N^{\omega}-nitro-L-arginine$, a nitric oxide synthase inhibitor. In focal cerebral ischemic rats, the amplitude of decrease in rCBF during ischemic period was significantly less in VEGF-treated group, compared with that in vehicle-treated group. The cerebral infarct size was reduced by VEGF in a dose-dependent manner. The brain edema formation was dose-dependently reduced by VEGF in 24-hour MCA occlusion group but not in 6-hour MCA occlusion group. It is suggested that VEGF not only improves the rCBF during cerebral ischemic period but also reduces the brain edema formation, and thereby exert a protective effect on focal cerebral ischemia in rats.