• 대한물리치료과학회지
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• 제2권3호
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• pp.587-598
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• 1995

The purpose of this study was to test the microcurrent electrical neuromuscular stimulation on muscle soreness, serum creatine kinase levels and force deficits evident following a high-intensity eccentric exercise bout. 10 volunteer male subjects were randomly assigned to a treatment group or to a control group. Exercise consisted of high-intensity eccentric contractions of the elbow flexors. Resistance was reduced as subjects fatigued, until they reached exhaustion. Muscle soreness rating was determined using a visual analog scale. Serum creatine kinase levels were analyzed using a blood sample. Force deficits were determined by measures of maximal voluntary isometric contraction at $90^{\circ}$ of elbow flexion on a Orthotron II dynamometer. Muscle soreness rating, serum creatine kinase levels and maximal voluntary isometric contraction were determined at the before exercise and again at 24 and 48 hours postexericse. Treatments were applied immediately following exercise. The control group subjects rested following their exercise bout. Statistical analysis showed significant increases in muscle soreness rating and significant decreases in maximal voluntary isometric contraction when the before exercise was compared with 24 and 48 hour measures(p<0.01). No significant effects were observed between groups in muscle soreness rating and maximal voluntary isometric contraction(p>0.05). Highly significants differences in serum creatine kinase levels were found using on Analysis of variance(ANOVA) repeated measures between groups for each time cycles(p<0.001). This modality may have benefits when used early stage in the muscle damage.

• 대한의용생체공학회:의공학회지
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• 제39권1호
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• pp.1-9
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• 2018

This study was carried out to evaluate the effect of micro-current therapy on muscle atrophy and delayed wound healing process caused by traumatic peripheral nerve injury. For this, twenty-five 5-week-old Sprague Dawley rat were used and assigned to five groups including the normal group (NOR, n=5), the wound group (WD, n=5), the wounded and treated with micro-current electrical therapy group (WD+MET, n=5), the sciatic nerve denervated and wounded group (WD+DN, n=5), and the sciatic nerve denervated, wounded and treated with micro-current electrical therapy group (WD+DN+MET, n=5). In order to assess the changes in length of incisional wound for 12 days and the muscle volume for 2 weeks, the ImageJ analysis of macroscopic analysis and micro-CT data were obtained and analyzed. As a result, significant delay in the process in wound healing were observed and micro-current therapy suppress the postponement of healing process. Furthermore, there were significant changes in muscle volume between electrically treated group and non-treated group. These result shows that electrical stimulation may improve the delayed healing process and muscle atrophy at once.

• The Journal of Korean Physical Therapy
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• 제20권1호
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• pp.67-73
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• 2008

Purpose: The purpose of this study was to investigate the effect of the intensity of microcurrent stimulation (with currents of 50 ${\mu}A$, 100 ${\mu}A$ and 300 ${\mu}A$ using a pulse frequency of 5 pps) on wound healing in rats. Methods: Sixty male Korean rats were randomly divided into four groups of 15 rats that were subjected to four different treatment protocols (control group, no treatment; experimental groups, treated with currents of 50 ${\mu}A$, 100 ${\mu}A$ or 300 ${\mu}A$). An experimental 20 mm linear wound was made in each animal and all animals in the experimental groups received microcurrent stimulation once a day for 20 minutes until the day of sacrifice on day 1, day 3 and day 6. An optical microscope was used to determine any histological changes. Results: The experimental results were as follows. 1. In an examination with the naked eye, all groups showed similar changes until the first day. However, from the third day, a little intercellular fluid soaked through wound region in the control group rats. In the experimental group animals, little intercellular fluid soaked through wound region, and swelling and redness did not appear, from the third day. 2. In an examination with histological evaluation, more significant changes were observed in all of the experimental group rats than the control group animals. Especially, a stimulation intensity of 50 ${\mu}A$ caused a more significant effect than the use of the other intensities by day 6 of wound healing. In addition, rapid recovery was observed. Conclusion: It was determined that microcurrent stimulation had a positive effect on wound healing. A stimulation intensity of 50 ${\mu}A$ was more effective than the other intensities (100 ${\mu}A$ and 300 ${\mu}A$) utilized for wound healing. Furthermore, low-intensity microcurrent stimulation was more effective for the purpose of wound healing.

• 대한의용생체공학회:의공학회지
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• 제39권6호
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• pp.284-296
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• 2018

Obesity is considered as a primary health problem over the past century in line with life environmental changes. It is mainly associated with increased risk of numerous chronic diseases which may significantly reduce health-related quality of life. Therefore, efforts to reduce weight should be performed. This study suggested a novel approach to reduce body fat by applying external stimulation which is micro-current stimulation (MCS). In this clinical study, we evaluated the potential effects of MCS for reduction of abdominal fat and weight loss. Prior to the clinical test, computational simulation was conducted to find the proper MCS conditions that allow externally applied stimulation to reach the internal fat section from the external skin. Particularly, the clinical study evaluated the unilateral effects of MCS for body fat loss and lipolysis without any additional limitations such as physical exercise and dietary therapy. The results showed that whole body fat, waist circumferences, and abdominal fat are gradually decreased after intervention in proportion to the time. From the results, we can estimate that MCS can be effective on the body fat loss by activation of lipolysis in human adipose.

• 대한의용생체공학회:의공학회지
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• 제41권6호
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• pp.235-246
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• 2020

This study aimed to evaluate the inhibitory effect of micro-current stimulation(MCS) on adipogenesis regarding with Wnt/β-catenin pathway using the ob/ob mouse and 3T3-L1 cell line. 6-week old ob/ob male mice were equally assigned to four groups: obese group(ob), obese with MCS groups(50 μA, 200 μA, and 400 μA). 6-week old C57BL/6J male mice were assigned to the control group(CON). We analyzed abdominal adipose tissue volume by using in vivo micro-CT and measured the body weight, feed intake, liver weight and triglycerides in serum. All the MCS groups showed that significantly reduced body weight and triglycerides in serum. In the case of liver weight and abdominal adipose tissue volume, the inhibitory effect of adipogenesis was shown in the 200 μA and 400 μA groups. To elucidate the anti-obesity effect of MCS, β-catenin, C/EBPα and FAS protein expressions were analyzed by western blotting. β-catenin expression was upregulated, C/EBPα and FAS expression were down-regulated in the relatively high-intensity groups(200 μA and 400 μA). Thus, the 200 μA and 400 μA for the intensity of MCS were chosen for cell experiments. In the 3T3-L1 cell line, Wnt/β-catenin pathway including Wnt10b, Wnt3a, β-catenin and Cyclin D1 was activated in all MCS groups. Accordingly, the expression level of C/EBPα was decreased during the differentiation and lipid droplet was significantly reduced in Oil red O staining results. These results suggest that the Wnt/β-catenin signaling might be activated by MCS with current intensities between 200-400 μA and it may lead to anti-obesity effects.

• 대한의용생체공학회:의공학회지
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• 제43권1호
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• pp.1-10
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• 2022

Non-alcoholic fatty liver disease(NAFLD) is excessive hepatic lipid accumulation mainly caused by obesity. This study aimed to evaluate whether micro-current stimulation(MCS) could modulate lipid metabolism regarding the Sirt1/AMPK pathway, fatty acid β-oxidation pathway, and lipolysis and lipogenesis-related factors in FL83B cells. For the NAFLD cell model, FL83B cells were treated with oleic acid for lipid accumulation. MCS were stimulated for 1 hr and used frequency 10 Hz, duty cycle 50%, and biphasic rectangular current pulse. The intensity of MCS was divided into 50, 100, 200, and 400 ㎂. Through the results of Oil red O staining, it was confirmed that MCSs with the intensity of 200 ㎂ and 400 ㎂ significantly reduced the degree of lipid droplet formation. Thus, these MCS intensities were applied to western blot analysis. Western blot analysis was performed to analyze the effects of MCS on lipid metabolism. MCS with the intensity of 400 ㎂ showed that significantly activated the Sirt1/AMPK pathway, a key pathway for regulating lipid metabolism in hepatocytes, and fatty acid β-oxidation-related transcription factors. Moreover, it activated the lipolysis pathway and suppressed lipogenesis-related transcription factors such as SREBP-1c, FAS, and PPARγ. In the case of MCS with the intensity of 200 ㎂, only PGC1α and SREBP-1c showed significant differences compared to cells treated only with oleic acid. Taken together, these results suggested that MCS with the intensity of 400 ㎂ could alleviate hepatic lipid accumulation by modulating lipid metabolism in hepatocytes.

• The Journal of Korean Physical Therapy
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• 제9권1호
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• pp.103-115
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• 1997

The purpose of this study was to examine the amount of $\beta-endorphin$ and pain threshold according to time sequences in applying experimented TENS and MENS(pre treatment, posttreatment, 25 minutes after the treatment). This test was to aim at showing the effects of the experimental $\beta-endorphin$ and pain threshold applied to the randomly selected twenty healthy men in their twenties. The subjects were divided into two group(ten for TENS and the other ten MENS). The results obtained are as follows : 1. There was no significant difference in the $\beta-endorphin$ between TENS and HENS(p>0.05). There was no difference in the pain threshold at pretreatment and posttreatment(p>0.05), but there was some difference at 25 minutes after the treatment(p<0.05). 2. The group of TENS in the experimental $\beta-endorphin$ had the highest level of $14.40{\pm}3.098$ at posttreatment, but the level decreased a little according to time passed. And in the experimental pain threshold, the level went to the highest plateau of $2.92{\pm}0.483$ at 25 minutes after the treatment. 3. The group of MENS in the experimental $\beta-endorphin$ had the highest plateau of $14.20{\pm}3.967$ at posttreatment, but the level decreased a bit according to time passed also. And in the experimental pain threshold, the level went to the highest plateau of $2.49{\pm}0.617$ posttreatment. 4. There were some differences of the experimental $\beta-endorphin$ in TENS group at pretreatment and posttreatment(p<0.05). There were some differences in the experimental pain threshold between pretreatment and posttreatment as well as between pretreatment and 25 minutes after the treatment(p<0.05) MENS did not influence the experimental $\beta-endorphin$ and pain threshold. This experiment showed that TENS increased the levels of the experimental $\beta-endorphin$ at posttreatment and increased the levels of the experimental pain threshold untill 25 minutes after the treatment. Therefore, the time of sustaining pain in TENS group was longer than that of MENS group. Also, MENS showed that it increased each level of the experimental $\beta-endorphin$ and pain threshold, but these levels were not statistically meaningful.

• 대한의용생체공학회:의공학회지
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• 제38권4호
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• pp.175-182
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• 2017

Microcurrent electrical stimulation(MES) has been used to accelerate recovery of atrophied skeletal muscle. However, convincing stimulation parameters for suppressing muscle atrophy due to injured sciatic nerve remains unclear. The objective of this study was to investigate the effective intensity of MES on restraining muscle atrophy with rat model underwent sciatic nerve injury(SNI). Twenty-5-week-old Sprague Dawley male rats were equally assigned to five groups : Control group(Control, CON, n = 4), Denervation group(Denervation, D, n = 4), Denervation with MES of $22{\mu}A$ group(Denervation + $22{\mu}A$, D+22, n = 4), Denervation with MES of $100{\mu}A$ group (Denervation + $100{\mu}A$, D+100 n = 4), Denervation with MES of $400{\mu}A$ group(Denervation + $400{\mu}A$, D+400, n = 4). To induce muscle atrophy, all rats in the D, D+22, D+100, and D+400 groups, were subjected to sciatic nerve injury on their right hindlimb and allowed to have 1 week of resting period. Following this period, rats underwent daily MES(60 min/ a day, 5times/1week) for 4 weeks. After that, we investigate morphological changes in muscle volume by using in vivo micro-computed tomography at week 0, 1, 3 and 5. After 5 weeks, the muscle volume had the highest value in D+400 group, and also noticeably increased in D+100 group compared to it in D group. The results of this study imply that MES with current intensities between $100-400{\mu}A$ can suppress muscle atrophy effectively.

• 한국전문물리치료학회지
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• 제18권1호
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• pp.83-92
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• 2011

Osteoarthritis is a degenerative joint disease and is led to physical disability. Yet the development of effective disease-modifying treatments has lagged. In this study, I examined the effect of physical therapeutic intervention through microcurrent stimulation and attempt to find which degree of intensity, either 25 ${\mu}A$ or 500 ${\mu}A$ with a regular 5 pps pulse, is more effective in the osteoarthritis. Osteoarthritis was induced with a mixture of 2% carrageenan and 2% kaolin in 26 male Sprague-Dawley rats. The mixture (0.1 $m{\ell}$) was injected into the intra-articular capsule of knee joint once a week for three weeks. Five animals did not show degenerative changes by radiological findings and excluded in the following experiment. Osteoarthritic animals were randomly divided into 3 groups ($n_1$, $n_2$, $n_3$=7/each): untreated, treated with 25 ${\mu}A$, treated with 500 ${\mu}A$. All experimental groups received microcurrent stimulation for four weeks (15 min/day, 5 days/week). The ethological inspection of foot print analysis on the walking corridor was accomplished every week. Histological preparations and immunohistochemical staining with insulin-like growth factor-1 were also done in the articular cartilages. All of these parameters were compared with those of osteoarthritic control group (n=7). The ethological inspection of foot print analysis revealed that changes of walking track (paw width) and stride length was significantly increased in both experimental groups. The better results were observed in experimental group treated with 25 ${\mu}A$ intensity without significance than group treated with 500 ${\mu}A$. Histological preparations disclosed that routine hyaline cartilage of articular surface were altered to fibrous cartilage in untreated group and experimental group treated with 500 ${\mu}A$ intensity. But a little changes were seen in experimental group treated with 25 ${\mu}A$ intensity. Immunolocalization of insulin-like growth factor-1 was simultaneously decreased according to the duration of osteoarthritis, and did not show significant difference among the groups. In this study discovered that the microcurrent stimulation, especially 25 ${\mu}A$ intensity, had a positive effect by the ethological inspection, histological and immunohistochemical stainings. These results suggest that microcurrent stimulation with low-intensity might be effective in the promotion of healing process for the osteoarthritis.

• Restorative Dentistry and Endodontics
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• 제34권4호
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• pp.333-339
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• 2009

현행 복합레진에서 가장 많이 사용되고 있는 광중합개시제의 일종인 camphoroquinone은 중합 효과가 적고 황색을 띠기 때문에 다른 개시제에 대한 연구가 이루어져 왔다. 이에 본 연구에서는 새로운 개시제인 OPPI (p-octyloxy-phenyl-phenyl iodonium hexafluoroantimonate)를 기존의 camphoroquinone, amine과 다양한 비율로 혼합한 다음, barium glass를 첨가한 실험용 복합레진을 제조하여 각 수복재의 미세누출도를 비교, 평가하였다. 총 4종의 단량체를 제조하였으며 camphoroquinone, OPPI, amine의 조성 중량비는 다음과 같다: A군 - 0.5%, 0%, 1% / B군 - 2%, 0.2%, 2% / C군 - 0.2%, 1%, 0.2% / D군 - 1%, 1%, 2%. 이후 평균 입자 크기 1 ${\mu}m$의 3.2% silane 처리된 barium glass를 중량비 78%로 섞어 복합레진을 제조하였다. 총 55개의 소구치에 치경부를 중심으로 원형 와동을 (직경; 근원심 폭경의 2/3, 깊이; 1.5 mm) 형성한 다음, 자가부식형 접착시스템인 Hybrid Bond로 처리하고 4종의 복합레진으로 수복하였다. 연마 후 치아를 섭씨 5도와 55도에서 각기 30초씩 담궈 500회의 열순환 처리하였으며 전기화학적 방법으로 전기 전도성을 2회 (열순환 처리 후, 1주 간격으로 식염수를 교환하며 3개월 보관 후) 측정, 비교하였다. 미세누출도는 시간 경과에 따라 커지는 양상을 보였으며, 열순환 처리 직후 4종 복합레진 사이에 차이를 보이지 않았지만, 3개월 보관 후에는 D군이 가장 적었으며 C군이 가장 큰 미세누출을 보였다. 열순환 자극 직후 차이를 보이지 않았지만, 3개월 보관 후 측정치로 미루어 볼 때, OPPI와 전반적인 중합시스템이 고농도로 함유된 복합레진(D군)과 CQ와 아민만을 사용한 전통적인 복합레진(A군)이 중합개시시스템을 저농도로 함유한 복합레진(C군)에 비해 우수한 밀폐효과를 보였다. 이는 시간의 흐름에 따라 접착계면의 퇴화가 일어났거나 일부 성분이 용해가 되어 나온 것으로 보이며 앞으로 이에 대한 더 많은 연구가 필요할 것으로 사료된다.