• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.154-161
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• 2024

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that causes progressive paralysis. L-Citrulline is a nonessential neutral amino acid produced by L-arginine via nitric oxide synthase (NOS). According to previous studies, the pathogenesis of ALS entails glutamate toxicity, oxidative stress, protein misfolding, and neurofilament disruption. In addition, L-citrulline prevents neuronal cell death in brain ischemia; therefore, we investigated the change in the transport of L-citrulline under various pathological conditions in a cell line model of ALS. We examined the uptake of [¹⁴C]L-citrulline in wild-type (hSOD1wt/WT) and mutant NSC-34/ SOD1^G93A (MT) cell lines. The cell viability was determined via MTT assay. A transport study was performed to determine the uptake of [¹⁴C]L-citrulline. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to determine the expression levels of rat large neutral amino acid transported 1 (rLAT1) in ALS cell lines. Nitric oxide (NO) assay was performed using Griess reagent. L-Citrulline had a restorative effect on glutamate induced cell death, and increased [¹⁴C]L-citrulline uptake and mRNA levels of the large neutral amino acid transporter (LAT1) in the glutamate-treated ALS disease model (MT). NO levels increased significantly when MT cells were pretreated with glutamate for 24 h and restored by co-treatment with L-citrulline. Co-treatment of MT cells with L-arginine, an NO donor, increased NO levels. NSC-34 cells exposed to high glucose conditions showed a significant increase in [¹⁴C]L-citrulline uptake and LAT1 mRNA expression levels, which were restored to normal levels upon co-treatment with unlabeled L-citrulline. In contrast, exposure of the MT cell line to tumor necrosis factor alpha, lipopolysaccharides, and hypertonic condition decreased the uptake significantly which was restored to the normal level by co-treating with unlabeled L-citrulline. L-Citrulline can restore NO levels and cellular uptake in ALS-affected cells with glutamate cytotoxicity, pro-inflammatory cytokines, or other pathological states, suggesting that L-citrulline supplementation in ALS may play a key role in providing neuroprotection.

• Annals of Clinical Neurophysiology
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• v.15 no.2
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• pp.53-58
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• 2013

Background: The autophagy is the major route for lysosomal degradation of misfolded protein aggregates and oxidative cell components. We hypothesized that rapamycin (autophagy enhancer) would prolong the survival of motor neuron and suppress the disease progression in amyotrophic lateral sclerosis (ALS). Methods: A total of 24 transgenic mice harboring the human G93A mutated SOD1 gene were used. The clinical status involving rotarod test and survival, and biochemical study of ALS mice model were evaluated. Results: The onset of symptoms was significantly delayed in the rapamycin administration group compared with the control group. However, after the clinical symptom developed, the rapamycin exacerbated the disease progression and shortened the survival of ALS mice model, and apoptosis signals were up-regulated compared with control group. Conclusions: Even though further detailed studies on the relevancy between autophagy and ALS will be needed, our results revealed that the rapamycin administration was not effective for being novel promising therapeutic strategy in ALS transgenic mice and exacerbated the apoptosis.

• The Korean Journal of Pain
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• v.22 no.3
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• pp.199-205
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• 2009

Background: A major ingredient of green tea is epigallocatechin-3-gallate (EGCG), and this is known to have many beneficial effects for cancer prevention and also on the cardiovascular system and neurodegenerative diseases through its anti-oxidant, anti-angiogenic, anti-inflammatory, lipid-lowering and neuroprotective properties. Its actions on nociception and the spinal nervous system have been examined in only a few studies, and in these studies EGCG showed an antinociceptive effect on inflammatory and neuropathic pain, and a neuroprotective effect in motor neuron disease. This study was performed to investigate the effect of EGCG on acute thermal pain and the development of morphine tolerance at the spinal level. Methods: The experimental subjects were male Sprague-Dawley rats and the Hot-Box test was employed. A single or double-lumen intrathecal catheter was implanted at the lumbar enlargement for drug administration. An osmotic pump was used to infuse morphine for 7 days for induction of morphine tolerance. EGCG was injected repeatedly for 7 days at twice a day through the intrathecal catheter. Results: Intrathecal EGCG increased the paw withdrawal latency (PWL) after repeated administration for 7 days at twice a day, but this did not happen with administering on single bolus injection of EGCG. In addition, the antinociceptive effect of intrathecal morphine was not affected by co-administration with EGCG. A continuous 7-day infusion of morphine caused a significant decrease of the PWL in the control group (M + S, morphine plus saline). In contrast, intrathecal EGCG injection over 7 days blocked the decrease of the PWL in the experiment group (M + E, morphine plus EGCG). Conclusions: Intrathecal ECGC produced a weak antinociceptive effect for acute thermal pain, but it did not change the morphine's analgesic effect. However, the development of antinociceptive tolerance to morphine was attenuated by administering intrathecal EGCG.

• The Journal of Pediatrics of Korean Medicine
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• v.14 no.1
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• pp.197-204
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• 2000

Neuromuscular disorders are common causes of weakness and hypotonia in the infantile period and in childhood. Accurate diagnosis of specific neuromuscular disorders depends first on identification of which aspect of the peripheral neuromuscular system is affected-the motor neuron in the spinal cord, the nerve root or peripheral nerve, the neuromuscular junction, or the muscle-and then on the determination of the etiology and specific clinical entity. Spinal muscular atrophy(SMA) is the most common autosomal-recessive genetic disorder lethal to infants. The three major childhood-onset forms of SMA are now usually called type I, type II and typeⅢ. Progression of the disease is due to loss of anterior horn cells, thought to be caused by apoptosis. Diagnosis is based on the course of the illness, as well as certain changes seen on nerve and muscle biopsy and electrodiagnostic studies. More recently, our understanding of the genetics of this disorder has provided a noninvasive approach to diagnosis. We report on a 3-year-old male patient with spinal muscular atrophy type II. He had progressive muscular weakness since 18 months of age. The upper arms were slightly, and the thighs moderately atrophic. There was muscle weakness of both the upper and lower limbs, being more proximal in distribution. Electromyogram revealed a neurogenic pattern.

• Physical Therapy Korea
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• v.9 no.2
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• pp.43-50
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• 2002

This study was designed to identify the effects of walking conditions (normal walking vs. toe-walking) on electromyographic (EMG) activity of gastrocnemius, tibialis anterior, and soleus muscle. Seven healthy adult males participated in this study. The exclusion criteria were orthopedic or neurologic disease, congenital anomaly or acquired deformity, or pain in low back or lower extremities. The maximal voluntary isometric contraction for each muscle was used for the reference contraction, and EMG activity of each muscle during normal walking and toe-walking was expressed as a percentage of reference contraction. The gait cycle was determined with two foot switches, and gait was normalized as 100% gait cycle for each condition. The maximal values of EMG activity in terminal stance (30~50% of gait cycle) of each condition were compared for data analysis. No significant differences were found in EMG activity of the tibialis anterior and soleus (p>.05), whereas significant decrement was found in EMG activity of gastrocnemius during toe-walking compared to normal walking (p<.05). There is a limitation to generalize the results of this study, because small number of subjects participated for this study and only EMG was used for data collection. The treatment methods should be developed to improve gait efficiency by substituting the weakened muscles secondary to upper motor neuron, or by strengthening the distal muscles in lower extremity.

• Journal of Veterinary Clinics
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• v.39 no.5
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• pp.235-239
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• 2022

A 10-year-old neutered male Siberian Husky presented with paraparesis and severe lethargy. On physical examination, the patient was unable to weight-bear and walk and exhibited significant muscle mass loss in both hindlimbs and generalized truncal alopecia with a dull coat of hair. On neurological examination, cranial lumbar vertebral pain, hind limb cross-extensor reflex, delayed hindlimb postural reaction, upper motor neuron bladder dysfunction, and total absence of cutaneous trunci reflex were identified. Computed tomography revealed diffuse idiopathic skeletal hyperostosis and spondylosis deformans of the cervical and thoracolumbar vertebrae. In addition, a generalized decrease in bone mineral density of the vertebrae was identified. Magnetic resonance imaging showed hyperplasia of the epidural fat compressing the spinal cord in the thoracolumbar region and concurrent mild multiple intervertebral disc herniations. No specific findings were observed in cerebrospinal fluid analysis. Blood analysis of thyroid function revealed decreased total T4 and free T4 levels, and increased TSH levels. The patient was tentatively diagnosed with spinal epidural lipomatosis (SEL) secondary to hypothyroidism. The patient was treated with levothyroxine, firocoxib, and gabapentin. Clinical signs gradually improved, and the patient showed normal ambulation 40 days after treatment initiation. SEL is extremely rare in dogs. To the best of our knowledge, this is the first case report of SEL secondary to hypothyroidism that was treated conservatively. Secondary SEL can be sufficiently managed by treating the underlying cause, if possible.

• Biomolecules & Therapeutics
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• v.15 no.1
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• pp.16-26
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• 2007

Tissue plasminogen activator (tPA) is a serine protease catalyzing the proteolytic conversion of plasminogen into plasmin, which is involved in thrombolysis. During last two decades, the role of tPA in brain physiology and pathology has been extensively investigated. tPA is expressed in brain regions such as cortex, hippocampus, amygdala and cerebellum, and major neural cell types such as neuron, astrocyte, microglia and endothelial cells express tPA in basal status. After strong neural stimulation such as seizure, tPA behaves as an immediate early gene increasing the expression level within an hour. Neural activity and/or postsynaptic stimulation increased the release of tPA from axonal terminal and presumably from dendritic compartment. Neuronal tPA regulates plastic changes in neuronal function and structure mediating key neurologic processes such as visual cortex plasticity, seizure spreading, cerebellar motor learning, long term potentiation and addictive or withdrawal behavior after morphine discontinuance. In addition to these physiological roles, tPA mediates excitotoxicity leading to the neurodegeneration in several pathological conditions including ischemic stroke. Increasing amount of evidence also suggest the role of tPA in neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis even though beneficial effects was also reported in case of Alzheimer's disease based on the observation of tPA-induced degradation of $A{\beta}$ aggregates. Target proteins of tPA action include extracellular matrix protein laminin, proteoglycans and NMDA receptor. In addition, several receptors (or binding partners) for tPA has been reported such as low-density lipoprotein receptor-related protein (LRP) and annexin II, even though intracellular signaling mechanism underlying tPA action is not clear yet. Interestingly, the action of tPA comprises both proteolytic and non-proteolytic mechanism. In case of microglial activation, tPA showed non-proteolytic cytokine-like function. The search for exact target proteins and receptor molecules for tPA along with the identification of the mechanism regulating tPA expression and release in the nervous system will enable us to better understand several key neurological processes like teaming and memory as well as to obtain therapeutic tools against neurodegenerative diseases.

• Molecules and Cells
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• v.41 no.8
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• pp.742-752
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• 2018

Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive degeneration of dopaminergic (DAergic) neurons, particularly in the substantia nigra (SN). Although circadian dysfunction has been suggested as one of the pathophysiological risk factors for PD, the exact molecular link between the circadian clock and PD remains largely unclear. We have recently demonstrated that $REV-ERB{\alpha}$, a circadian nuclear receptor, serves as a key molecular link between the circadian and DAergic systems. It competitively cooperates with NURR1, another nuclear receptor required for the optimal development and function of DA neurons, to control DAergic gene transcription. Considering our previous findings, we hypothesize that $REV-ERB{\alpha}$ may have a role in the onset and/or progression of PD. In the present study, we therefore aimed to elucidate whether genetic abrogation of $REV-ERB{\alpha}$ affects PD-related phenotypes in a mouse model of PD produced by a unilateral injection of 6-hydroxydopamine (6-OHDA) into the dorsal striatum. $REV-ERB{\alpha}$ deficiency significantly exacerbated 6-OHDA-induced motor deficits as well as DAergic neuronal loss in the vertebral midbrain including the SN and the ventral tegmental area. The exacerbated DAergic degeneration likely involves neuroinflammation-mediated neurotoxicity. The $REV-erb{\alpha}$ knockout mice showed prolonged microglial activation in the SN along with the over-production of interleukin $1{\beta}$, a pro-inflammatory cytokine, in response to 6-OHDA. In conclusion, the present study demonstrates for the first time that genetic abrogation of $REV-ERB{\alpha}$ can increase vulnerability of DAergic neurons to neurotoxic insults, such as 6-OHDA, thereby implying that its normal function may be beneficial for maintaining DAergic neuron populations during PD progression.

• Molecules and Cells
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• v.37 no.3
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• pp.226-233
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• 2014

Excessive reactive oxygen species (ROS) generated from abnormal cellular process lead to various human diseases such as inflammation, ischemia, and Parkinson's disease (PD). Sensitive to apoptosis gene (SAG), a RING-FINGER protein, has anti-apoptotic activity and anti-oxidant activity. In this study, we investigate whether Tat-SAG, fused with a Tat domain, could protect SH-SY5Y neuroblastoma cells against 1-methyl-4-phenylpyridinium ($MPP^+$) and dopaminergic (DA) neurons in the substantia nigra (SN) against 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine (MPTP) toxicity. Western blot and immunohistochemical analysis showed that, unlike SAG, Tat-SAG transduced efficiently into SH-SY5Y cells and into the brain, respectively. Tat-SAG remarkably suppressed ROS generation, DNA damage, and the progression of apoptosis, caused by $MPP^+$ in SH-SY5Y cells. Also, immunohistochemical data using a tyrosine hydroxylase antibody and cresyl violet staining demonstrated that Tat-SAG obviously protected DA neurons in the SN against MPTP toxicity in a PD mouse model. Tat-SAG-treated mice showed significant enhanced motor activities, compared to SAG- or Tat-treated mice. Therefore, our results suggest that Tat-SAG has potential as a therapeutic agent against ROS-related diseases such as PD.

• Journal of Acupuncture Research
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• v.24 no.4
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• pp.225-235
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• 2007

Amyotrophic Lateral Sclerosis(ALS) is Motor Neuron Disease(MND) that reveals muscle relaxation, bulbar palsy, extremities weakness, Pneumonia, in severe case, leads to death. Objectives : Amyotrophic Lateral Sclerosis is one of the incurable disease. In Oriental medicine, Wei symptom is similar as Amyotrophic Lateral Sclerosis, so we diagnosed it as Wei symptom and treated in Oriental medical system. Methods : The patient was treated by acupunture, moxibustion, herb medication, physical treatment. The improvement of the patient was judged by Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS), Grasping power on right arm, circumference of thigh and calf. Result : The patient had better condition for a while but the sputum irritated breathing and the day before he discharged vital sign was not stable and could not breath well. Conclusion : It is necessary to have more examination about the incurable syndromes such as Amyotrophic Lateral Sclerosis, and keep the patient's life better and expand their lives.