• International Journal of Oral Biology
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• v.33 no.1
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• pp.1-5
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• 2008

Adenosine 5'-triphosphate (ATP) is an important extracellular signaling molecule which is involved in a variety of physiological responses in many different tissues and cell types, by acting at P2 receptors, either ionotropic (P2X) or G protein-coupled metabotropic receptors (P2Y). P2X receptors have seven isoforms designated as $P2X_{1^-}P2X_7$. In this study, we investigated the electrophysiological and pharmacological properties of rat $P2X_{1^-}P2X_4$ currents by using whole-cell patch clamp technique in a heterologous expression system. When ATP-induced currents were analyzed in human embryonic kidney (HEK293) cells following transient transfection of rat $P2X_{1^-}P2X_4$, the currents showed different pharmacological and electrophysiological properties. ATP evoked inward currents with fast activation and fast desensitization in $P2X_{^1-}$ or $P2X_{3^-}$ expressing HEK293 cells, but in $P2X_{2^-}$ or $P2X_{4^-}$ expressing HEK293 cells, ATP evoked inward currents with slow activation and slow desensitization. While PPADS and suramin inhibited $P2X_2$ or $P2X_3$ receptor-mediated currents, they had little effects on $P2X_4$ receptor-mediated currents. Ivermectin potentiated and prolonged $P2X_4$ receptor-mediated currents, but did not affect $P2X_2$ or $P2X_3$ receptor-mediated currents. We suggest that distinct pharmacological and electrophysiological properties among P2X receptor subtypes would be a useful tool to determine expression patterns of P2X receptors in the nervous system including trigeminal sensory neurons and microglia.

• Journal of Yeungnam Medical Science
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• v.22 no.1
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• pp.52-61
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• 2005

Background: Guillain-Barre syndrome is defined as a recognizable clinical entity that is characterized by rapidly evolving symmetric limb weakness, the loss of tendon reflexes, absent or mild sensory signs, and variable autonomic dysfunctions. This study evaluated the clinical and electrophysiological findings retrospectively. Materials and Methods: Forty-five patients with Guillain-Barre syndrome, who were admitted to the Yeungnam University Hospital for six years from Jan. 1994 to Dec. 1999 were investigated. The correlation between the clinical manifestation and the electrophysiological study was evaluated. Results: The male to female ratio was 1.8:1 and there was a peak seasonal incidence in the winter. A preceding illness was noted in 66.7 % of cases, and an upper respiratory tract infection was the most common one. The most common clinical manifestations were a loss of tendon reflex and ascending muscle weakness and paralysis. The cerebrospinal fluid examinations revealed, albuminocytologic dissociation in 33 cases (73.3 %). Intravenous immunoglobulin therapy was performed in 29 cases (64.4 %). The sequential electrophysiological abnormalities were most marked at 2 to 4 weeks after onset. At that time the most significant change was a decrease in the compound muscle action potential amplitude. These 45 patients with Guillain-Barre syndrome were subclassified using the clinical and electrophysiological data. Conclusion: The result in this study, concured with other research on the clinical and electrophysiological data of Guillain-Barre syndrome. However, an extensive and dynamic investigation is necessary to determine the reason for the peak seasonal incidence in winter.

• Journal of Yeungnam Medical Science
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• v.41 no.3
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• pp.220-227
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• 2024

Background: Electrodiagnostic testing (EDX) is important in the diagnosis and follow-up of neuropathic and myopathic diseases. This study aimed to demonstrate the compatibility between clinical prediagnosis and electrophysiological findings. Methods: EDX results from 2004 to 2020 at the physical medicine and rehabilitation (PM&R) clinic were screened. Tests with missing data, reevaluation studies, and cases of peripheral facial paralysis were excluded. The clinical prediagnosis and EDX results were recorded, and their compatibility was evaluated. Results: A total of 2,153 tests were included in this study. The mean age was 49.0±13.9 years and 1,533 of them (71.2%) were female. The most frequently referred clinic was the PM&R clinic (90.0%). Numbness (73.6%) was the most common complaint, followed by pain (15.3%) and weakness (13.9%). The most common prediagnosis was entrapment neuropathy (55.3%), radiculopathy (16.1%), and polyneuropathy (15.7%). Carpal tunnel syndrome was the most frequently identified type of entrapment neuropathy (78.3%). Six hundred and seventy EDX results (31.1%) were within normal limits. While the EDX results were consistent with the prediagnosis in 1,328 patients (61.7%), a pathology different from the prediagnosis was detected in 155 patients (7.2%). In the discrepancy group, the most common pathologies were entrapment neuropathy (51.7%), polyneuropathy (17.3%), and radiculopathy (15.1%). The most common neuropathy type was carpal tunnel syndrome (79.3%). Conclusion: After adequate anamnesis and physical and neurological examinations, requesting further appropriate tests will increase the prediagnosis accuracy and prevent unnecessary expenditure of time and labor.

• The Journal of the Korean dental association
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• v.38 no.4 s.371
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• pp.378-384
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• 2000

• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.462-467
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• 2019

Many studies in recent decades have revealed that olfactory stimulation by perfume or malodor inhalation exerts various psychological and physiological effects on humans. The most recent studies have examined the electrophysiological response of olfactory stimulation on the activity of human cortical nerve cells. The purpose of this current study is to quantitatively analyze what changes occur in the alpha activity in healthy participants (N=12) on olfactory stimulation using two types of odors (acacia and butanol). Exposure to the odor of acacia perfume was associated with a significant increase (66.7%) in alpha activity when compared with that of the no-odor background EEG. Exposure to the odor of butanol was associated with a significant reduction (33.3% to 41.7%) in EEG alpha activity when compared with that of the no-odor control. The results of this study demonstrated the potential to alter the cerebral cortex activity by olfactory stimulation. The results also suggest that olfactory perception has stimulatory effects on the function of the nervous system. In other words, it could be concluded from this study that inhalation of olfactory stimulation affected brain wave activities and mood states. Further research is needed to completely understand and describe the electrophysiological effects of different odors on the central nervous system.

• Annals of Clinical Neurophysiology
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• v.20 no.2
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• pp.101-104
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• 2018

Multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy is a variant of chronic acquired demyelinating polyneuropathy. A 65-year-old women presented with upper arm weakness. A nerve conduction study showed conduction blocks over intermediate segments with sparing of distal compound action potentials. Magnetic resonance imaging revealed asymmetric hypertrophy of the brachial plexus on the affected side. These findings represent important electrophysiological and radiological evidence of MADSAM neuropathy. The condition of the patient began to improve after starting intravenous immunoglobulin administration.

• Clinical and Experimental Pediatrics
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• v.54 no.12
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• pp.507-511
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• 2011

Purpose: The aim of the present study was to evaluate the characteristics of electrophysiologic studies (EPS) and radiofrequency ablation (RFA) performed in subjects aged less than 30 years with Wolff-Parkinson-White (WPW) syndrome, particularly pediatric patients under 18 years of age, based on our experience. Methods: Two hundred and one consecutive patients with WPW syndrome were recruited and divided to 3 groups according to age: group 1, 6 to 17 years; group 2, 18 to 29 years; and group 3, 30 to 60 years. The clinical, electrophysiological, and therapeutic data for these patients were evaluated by a retrospective medical record review. Results: A total of 73 (36%) of these patients were <30 years of age. Although there were more males than females in group 2 (male:female, 31:11), there was no sex difference in group 1 (male:female, 16:15). Left accessory pathway was detected less frequently in group 1 (32%, 10/31) than in group 2 (57%, 24/42) and group 3 (63%, 81/128) (P=0.023 and P=0.002, respectively). Conclusion: The present study describes several different electrophysiological characteristics in children and adolescents with WPW syndrome. Therefore, when EPS and RFA are performed in children and adolescence with WPW syndrome, we recommend that these characteristics be considered.

• Annals of Clinical Neurophysiology
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• v.4 no.1
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• pp.34-37
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• 2002

Background : The term "mononeuropathy multiplex" means simultaneous or sequential involvement of individual noncontiguous nerve trunks, evolving over days to years. The aim of this study was to delineate the causes, clinical features, and detailed electrophysiological findings in the patients with mononeuropathy multiplex. Methods : We analyzed the medical records of 22 patients with mononeuropathy multiplex confirmed on electrophysiological studies in Inje University Seoul Paik Hospital, Seoul Municipal Boramae Hospital, and Seoul National University Hospital between 1991 to 2000. Results : The number of male and female patients was equal. The mean age was 48 years with a peak incidence in the sixth decade. The etiology could be divided into vasculitis(11 patients) or non-vasculitis group. In vasculitis group, Churg-Strauss syndrome, polyarteritis nodosa, and rheumatoid arthritis were included. The non-vasculitis group included diabetes mellitus, leprosy, and Guillain-Barre syndrome. Ulnar and median nerves were most commonly involved(91%). In descending order of frequency, peroneal, posterior tibial, sural, and radial nerves were also involved. Bilateral involvement occurred most commonly in ulnar nerve. The symptoms and signs of mononeuropathy multiplex were the initial manifestations in 12 patients(55%), which was more frequent in vasculitis group(73%). Nerve conduction abnormalities could be divided into axonal, demyelinating, or mixed type. Most(91%) of the patients in vasculitis group revealed axonal type abnormalities. The location of the nerve lesion was frequently related to potential site of entrapment in demyelinating type. Conclusions : Mononeuropathy multiplex is the presenting features of the etiological disease frequently, especially in vasculitis group. Nerve conduction studies(NCS) reveals not only axonal type but also demyelinating type abnormalities. The etiological diseases were different in each type. Therefore, NCS is very helpful for the early etiological diagnosis and therapeutic implication in the patients with mononeuropathy multiplex.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.4
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• pp.439-447
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• 2017

Myotonia congenita (MC) is a genetic disease that displays impaired relaxation of skeletal muscle and muscle hypertrophy. This disease is mainly caused by mutations of CLCN1 that encodes human skeletal muscle chloride channel (CLC-1). CLC-1 is a voltage gated chloride channel that activates upon depolarizing potentials and play a major role in stabilization of resting membrane potentials in skeletal muscle. In this study, we report 4 unrelated Korean patients diagnosed with myotonia congenita and their clinical features. Sequence analysis of all coding regions of the patients was performed and mutation, R47W and A298T, was commonly identified. The patients commonly displayed transient muscle weakness and only one patient was diagnosed with autosomal dominant type of myotonia congenita. To investigate the pathological role of the mutation, electrophysiological analysis was also performed in HEK 293 cells transiently expressing homo-or heterodimeric mutant channels. The mutant channels displayed reduced chloride current density and altered channel gating. However, the effect of A298T on channel gating was reduced with the presence of R47W in the same allele. This analysis suggests that impaired CLC-1 channel function can cause myotonia congenita and that R47W has a protective effect on A298T in relation to channel gating. Our results provide clinical features of Korean myotonia congenita patients who have the heterozygous mutation and reveal underlying pathophyological consequences of the mutants by taking electrophysiological approach.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.237-245
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• 2010

Nerve conduction studies (NCS) are the most objective measure of nerve function and essential for the diagnosis of sub-clinical neuropathy in diabetes mellitus and diabetic polyneuropathy (DPN). This study evaluates the characteristic of electrophysiological abnormalities in DPN. Electrodiagnostic data from 120 patients with diabetic polyneuropathies and 77 control subjects were reviewed. Motor nerve conduction velocities (MNCV), distal motor latencies (DML), compound muscle action potential (CMAP) amplitudes, No potential frequency and conduction block were analyzed. Data were normalized based on normative reference values, and the proportion of nerves with abnormal values in the lower and upper limbs were evaluated. DPN was systemic demyelinating peripheral polyneuropathy and more severe abnormal nerve conduction was found in lower limbs than in upper limbs. The abnormal degree was more severe in peroneal nerve. It was no statistically significant difference of conduction block in control and DPN group. Our findings suggest that DPN had more common and severe peroneal nerve involvement in the motor nerve conduction studies (MNCS). These findings have important implications for the electrophysiological evaluation of DPN.