• Title/Summary/Keyword: Skeletal effects

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A Study on the Middle Step of Rabbit Skeletal Muscle Membrane Contraction by Analog Effects (아날로그에 효과에 의한 토끼 근육 막 수축의 중간단계 연구)

  • Kim, Duck-Sool
    • Journal of the Korean Applied Science and Technology
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    • v.24 no.1
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    • pp.61-66
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    • 2007
  • X-ray diffraction studies have been made to investigate the effects of binding of ADP, ADP+Vi, ADP+AIF4, $ADP+BeF_3$ on the structure of glycerinated rabbit skeletal muscle in the rigor state. Although these phosphate analogs are known to bind actively cycling myosin heads, it is not clear whether they can bind to the attached heads in the rigor muscle. We have found that these analogs can bind to the myosin heads attached to actin filaments in the rigor state. The present results indicate that (1) bound myosin heads altered their conformation in the proximal end toward the plane perpendicular to the fiber axis when MgADP bound to them, and (2) myosin heads were dissociated substantially (up to 50%) from actin filaments but still remained in the vicinity of actin filaments when MgADP and metallofluorides (AIF4 and BeF3) or vanadate bound to them. We detected new conformations of myosin heads attached to actin filaments when they had MgADP or ADP.Pi analogs. We report here these findings on the effects of MgADP and MgADP+phosphate analogs to the rigor crossbridges.

Comparison of the effects on the pharyngeal airway space of maxillary protraction appliances according to the methods of anchorage

  • Seo, Won-Gyo;Han, Se-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.39
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    • pp.3.1-3.9
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    • 2017
  • Background: The purpose of the study is to compare the effects on the pharyngeal airway space of skeletal anchored face mask with those of tooth-borne facemask. Methods: We used two types of facemask for maxillary protraction, the tooth-borne facemask (TBFM) and the skeletal anchored facemask (SAFM), and evaluated the effects of each facemask on the pharyngeal airway. Twenty-eight patients (mean age 10.3 years) were treated with the TBFM and 24 patients (mean age 11.2 years) were treated with the SAFM. Lateral cephalometric radiographs were taken before treatment (T1) and after treatment (T2) to assess changes in the dimensions of the upper airway. Statistical analysis was performed with independent t tests, matched t tests, Mann-Whitney U tests, and Kruskal-Wallis tests. Results: There were marked increases in upper airway dimensions in both groups following treatment, but the SAFM group had a significantly greater increase in airway dimensions than the TBFM group. Also, the SAFM subgroups showed more improved airway measurements than the TBFM subgroups in both the superior and inferior pharyngeal airways. Conclusions: SAFM is more effective than TBFM in increasing upper airway dimensions.

Effects of 17-DMAG Administration on Autophagy Flux in Mouse Skeletal Muscle (17-DMAG이 마우스 골격근에서 autophagy flux에 미치는 영향)

  • Ju, Jeong-sun;Lee, Yoo-Hyun
    • Journal of Life Science
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    • v.26 no.4
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    • pp.387-397
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    • 2016
  • The purpose of this study was to determine if heat shock proteins are involved in autophagy in skeletal muscle. We used the autophagy flux strategy, which is an LC3 II/p62 turnover assay conducted with and without an autophagy inhibitor, to determine whether 17-DMAG (an Hsp90 inhibitor/Hsp72 activator) stimulates autophagy in skeletal muscle. We treated C2C12 cells with 17-DMAG (500 nM) for 24 hr with and without the autophagy inhibitor (Bafilomycin A1, 200 ng/ml), and we injected C57BL/6 mice i.p. with 17-DMAG (10 mg/kg) daily for 7 days with and without colchicine as an autophagy inhibitor (0.4 mg/kg/day, administered on the last 2 days). C2C12 myotubes and tibialis anterior muscles were harvested for analysis of mTOR-dependent autophagy signaling pathway proteins and autophagic marker proteins (p62 and LC3 II) by Western blot analysis. The blots showed that 17-DMAG upregulated hsp72 and decreased Akt protein levels and S6 phosphorylation in C2C12 cells. However, an in vitro autophagic flux assay demonstrated that 17-DMAG did not increase LC3 II and p62 protein concentrations to a greater extent than Bafilomycin A1 treatment alone. Similarly, 17-DMAG increased Hsp72 protein levels and decreased the expression of Akt and the phosphorylation of S6 in mouse skeletal muscle. However, unlike the response seen in C2C12 myotubes, the p62 protein levels were significantly decreased in 17-DMAG-treated mouse skeletal muscle (~50%; p<0.05). The LC3 II protein levels in 17-DMAG-treated mice were increased ~2-fold more when degradation was inhibited by colchicine (p<0.01). This suggests that 17-DMAG stimulates basal autophagy in skeletal muscle but is not found in C2C12 myotubes.

Effect of Allopurinol on Ultrastructural Changes in Ischemia Reperfusion Injury to Skeletal Muscle of Rats After Graded Periods of Complete Ischemia (흰쥐에서 허혈시간에 따라 재관류후 나타나는 근조직의 미세구조 변화에 allopurinol이 미치는 영향)

  • Paik, Doo-Jin;Chun, Jae-Hong
    • Applied Microscopy
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    • v.25 no.3
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    • pp.51-62
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    • 1995
  • It has been well known that ischemia and reperfusion injury to skeletal muscle following an acute arterial occlusion causes significant morbidity and mortality. The skeletal muscle, which contains high energy phosphate compounds, has ischemic tolerance. During the ischemia, the ATP is catalyzed to hypoxanthine anaerobically and hypoxanthine dehydrogenase is converted to xanthine oxidase. During reperfusion, the hypoxanthine is catalyzed to xanthine by xanthine oxidase under $O_2$, presence and that results in production of cytotoxic oxygen free radicals. These cytotoxic free radicals, $O_2^-,\;H_{2}O_2,\;OH^-$, are toxic and make lesions in skeletal muscle during reperfusion. The authors perform the present study to investigate the effects of allopurinol, the inhibitor of xanthine oxidase, on reperfused ischemic skeletal muscles by observing the ultrastructural changes of the muscle fibers. A total of 48 healthy Sprague-Dawley rats weighing from 200 g to 250 g were used as experimental animals. Under urethane(3.0mg/kg., IP) anesthesia, lower abdominal incision was done and the left common iliac artery were ligated by using vascular clamp for 1, 2 and 6 hours. The left rectus femoris muscles were obtained at 6 hours after the removal of vascular clamp. In the allopurinol pretreated group, 50mg/kg of allopurinol was administered once a day for 2 days and before 2 hours of ischemia. The specimens were sliced into $1mm^3$ and prepared by routine methods for electron microscopic observations. All preparations were stained with uranyl acetate and lead citrate, and then observed with Hitachi -600 transmission electron microscope. The results were as follows: 1. In 1 hour ischemia/6 hours reperfused rectus femoris muscles of rats, decreased glycogen particles and electron density of mitochondrial matrix and dilated terminal cisternae are seen. In 2 hours ischemia/6 hours repersed rectus femoris muscles of rats, mitochondria with electron lucent matrix, irregularly dilated triad and spheromembranous bodies are observed. In 6 hours ischemia/6 hours reperfused rectus femoris muscles of rats, irregularly arranged myofibrils, and many spheromembranous bodies, fat droplets and lysosome are seen. 2. In 1 hour ischemia/6 hours reperfused rectus femoris muscles of rats pretreated with allopurinol, decreased glycogen particle and dilated cisternae of sarcoplasmic reticulum and triad are observed. In 2 hours ischemia/6 hours reperfused rectus femoris muscles of rats pretreated with allopurinol decreased electron density of mitochondrial matrix and spheromembranous bodies are seen. In 6 hours ischemia/6 hours reperfused rectus femoris muscles of rats pretreated with allopurinol, mitochondria with electron lucent matrix, spheromembranous bodies and dilated cisternae of sarcoplasmic reticulum and terminal cistern are observed. The results suggest that the allopurinol attenuates the damages of the skeletal muscles of rats during ischemia and reperfusion.

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Inhibitory Effect on RANKL-Induced Osteoclast Differentiation by Water Extract of Zizyphus Jujuba Mill (대추 물 추출물이 RANKL에 의해 유도되는 파골세포 분화에 미치는 영향)

  • Yoon, Kang Hugh;Baek, Jong Min;Kim, Ju Young;Kwak, Seong Cheoul;Cheon, Yoon Hee;Jeon, Byung Hoon;Lee, Chang Hoon;Choi, Min Kyu;Oh, Jaemin;Lee, Myeung Su;Kim, Jeong Joong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.28 no.1
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    • pp.29-34
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    • 2014
  • Bone homeostasis is maintained by balance between bone resorbing-osteoclasts and bone forming-osteoblasts. Excessive osteoclastic bone resorption plays a critical role in bone destruction in pathological bone diseases such as osteoporosis, rheumatoid arthritis, and periodontal disease. Many compounds derived from natural products have pharmacological applications and have therapeutic value for treating or preventing several bone diseases characterized by excessive bone resorption. To discover new compounds that can act as anti-resorptive agents, we screened for natural compounds that regulate osteclast differentiation, and found that water extract of Ziziphus Jujuba Mill (WEZJ) has inhibitory effects on osteoclast differentiation. In this study, WEZJ clearly inhibits the osteoclast differentiation in the presence of receptor activator of nuclear factor kB (RANKL), macrophage colony-stimulating factor (M-CSF) without cytoxicity by blocking activation of nuclear factor of activated T cells (NFAT)c1, and c-Fos. In signaling pathway, the phosphorylation of Akt, p38, c-Jun N-terminal kinases (JNK), extracellular signal-regulated kinases (ERK) and the expression of osteoclast-associated receptor (OSCAR), tartrate-resistant acid phosphates (TRAP), Integrin av, Integrin b3, Cathepsin K are suppressed, too. These result suggest that WEZJ may have therapeutic value for treating or preventing several bone diseases characterized by excessive bone destruction.

Insulin-like Growth Factor-I Induces Plectin and MACF1 Expression in C2C12 Myotubes (C2C12 myotube에서 insulin-like growth factor-I이 plectin과 MACF1 발현에 미치는 영향)

  • Kim, Hye Jin;Hwang, Ji Sun;Kwak, Yi-Sub;Lee, Won Jun
    • Journal of Life Science
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    • v.22 no.12
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    • pp.1651-1657
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    • 2012
  • Plectin and microtubule actin cross-linking factor 1 (MACF1) are architectural proteins that contribute to the function of skeletal muscle as generators of mechanical force. However, the influence of insulin- like growth factor-I (IGF-I), a master regulator of skeletal muscle cells, on plectin and MACF1 in skeletal muscle cells has not been demonstrated. The effect of IGF-I on plectin and MACF1 gene expression was investigated by treating differentiated C2C12 murine skeletal muscle cells with 20 ng/ml of IGF-I at different time points. The IGF-I treatment increased plectin protein expression in a dose-dependent manner. The mRNA level of plectin was measured by real-time quantitative PCR to determine if plectin induction was regulated pretranslationally. IGF-I treatment resulted in a very rapid induction of plectin mRNA transcript in C2C12 myotubes. Plectin mRNA increased by 140 and 180% after 24 and 48 hours of IGF-I treatment, respectively, and returned to the control level after 72 hours of IGF-I treatment. MACF1 mRNA increased 86 and 90% after 24 and 48 hours of IGF-I treat-ment, respectively, and returned to the control level after 72 hours of IGF-I treatment. These results suggested that the plectin gene is regulated pretranslationally by IGF-I in skeletal muscle cells. In conclusion, IGF-I induces a rapid transcriptional modification of the plectin and MACF1 genes in C2C12 skeletal muscle cells and has modulating effects on a cytolinker protein as well as on contractile proteins.

Effects of Facemask Therapy for Class III Malocclusions in Patients with Different Vertical Skeletal Patterns (3급 부정교합 환자의 수직적 골격 양상에 따른 facemask 치료 효과 비교)

  • Lee, Eunha;Park, Kitae
    • Journal of the korean academy of Pediatric Dentistry
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    • v.42 no.2
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    • pp.126-135
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    • 2015
  • The purpose of this study was to evaluate the skeletal and dentoalveolar effects of facemask therapy and to compare the anchorage of a bonded expander in patients with Class III malocclusion and different vertical skeletal patterns. Twenty subjects with Class III malocclusion were included in this study and were treated with a facemask and bonded expander. Based on the FMA, subjects were divided into two groups of 10 patients each: a high vertical group (HV; mean FMA $33.56^{\circ}$) and an average vertical group (AV; mean FMA $24.88^{\circ}$). Lateral cephalograms were taken and evaluated before and after treatment. In both groups, forward movement of the maxilla and backward rotation of the mandible were observed after treatment, with no statistical differences between the groups. Vertical skeletal variables increased in both groups, but the increase of FMA was significantly larger in the HV group than the AV group. Mesial movement of maxillary molars and proclination of maxillary incisors which indicate anchorage loss of bonded expander were observed in both groups, with no significant differences between the groups. In conclusion, facemask therapy resulted in effective maxillary protraction in both HV and AV groups. However, the open bite tendency was increased more in the HV group.

Effects of Soluble Dietary Fiber on Skeletal Muscle GLUT4 Protein Contents in SHRSP Fed a High-Fat Diet (고지방식유래의 뇌졸중 유발 고혈압 흰쥐(SHRSP)에 있어서 수용성 식이 섬유의 급여가 근섬유 형태에 따른 GLUT4 발현에 미치는 영향)

  • 송영주
    • Journal of Nutrition and Health
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    • v.33 no.7
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    • pp.712-716
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    • 2000
  • The Purpose of this study is to investigate the effect of soluble dietary fiber psyllium on insulin sensitivity and skeletal muscle glucose transporter 4(GLUT4) protein expression in stroke-prone hypertensive rats(SHRSP) fed a high-fat diet containing 5% of psyllium or cellulose from five to nine weeks of age. Obtained results were as follows : (1) In the psyllium diet group fasting plasma glucose level was significantly reduced and glucose levels upon oral glucose tolerance test were significantly lower than cellulose diet group at 30 min(p<0.05) and 60 min(p<0.01) (2) Skeletal muscle GLUT4 contents were significantly increased in the soleus(slow twitch) and extensor digitorum longus(fast twitch) muscle of psyllium diet group. (3) However there was no difference in insulin levels in the fasting and oral glucose tolerance test. These results indicated that psyllium diet improves peripheral insulin sensitivity but not insulin secretion. In conclusion our present finding suggest that soluble fiber diet is effective to increase insulin sensitivity in SHRSP. From these results it was suggested that soluble dietary fiber supplementation effectively prevents insulin resistance.

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Stability of Proteasomes Extracted from Pressurized, Aged Skeletal Muscles

  • Yamamoto, Shuhei;Suzuki, Atsushi;Nishiumi, Tadayuki
    • Asian-Australasian Journal of Animal Sciences
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    • v.22 no.2
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    • pp.282-288
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    • 2009
  • The present paper describes the effects of pressure and post-mortem aging treatments on in situ proteasome activity in rabbit and bovine skeletal muscles. Synthetic peptide hydrolyzing activity of rabbit proteasomes remained in the muscle after exposure to pressures up to 100 MPa. However, when a pressure of 400 MPa or more was applied, proteasomes were markedly inactivated. The extraction of proteasomes from excessively pressurized muscle appeared to be difficult. Proteasomes in aged muscle remained relatively stable throughout the aging process, with activity after 168 h (7 days) being 35%, 48%, 53% and 31% of the 0 h post-mortem LLVY, LSTR, AAF and LLE total hydrolyzing activities, respectively. The synthetic peptide hydrolyzing activities of bovine muscle proteasomes were similar to those of rabbit skeletal muscle proteasomes. The results suggest that synthetic peptide hydrolyzing activity remains in muscle exposed to relatively low pressures. Furthermore, it is known that high-pressure treatment induces fragmentation of myofibrils, modification of actin-myosin interaction and activation of intramuscular proteinases, cathepsins and calpains. Thus, proteasomes are probably involved in the tenderization process in combination with other intramuscular proteinases under high-pressure conditions. Our findings confirmed that proteasomes play a role in meat tenderization induced by high-pressure treatment or aging.

The Effect of Melatonin on Biochemical Changes after Ischemia-Reperfusion Injury of Rat Skeletal Muscle (흰쥐 골격근의 허혈-재관류 손상후 생화학적 변화에 미치는 Melatonin의 효과)

  • Park, Hye June;Burm, Jin Sik
    • Archives of Plastic Surgery
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    • v.32 no.6
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    • pp.683-688
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    • 2005
  • The ischemia-reperfusion injury of the skeletal muscles is caused by generation of reactive oxygen during ischemia and reperfusion. Melatonin or N-Acetyl-5-methoxy- tryptamine is suggested to have antioxidant effects in several tissues. In present study, we examined the protective effect of melatonin in a rat hind limb ischemia-reperfusion injury. Dimethyl-sulfoxide(DMSO) was also tested for comparison. Ischemia was induced for 4 hours by vascular clamping and followed by 1 hour or 24 hours of reperfusion. Muscle injury was evaluated in 4 groups such as single laparotomy group(control), ischemia-reperfusion group, DMSO group, melatonin group. Eedema ratio and malondialdehyde(MDA) of muscle tissue and serum level of creatine kinase(CK), were measeured at the end of reperfusion. DMSO and melatonin group showed significant amelioration of edema and serum CK compared with ischemia-reperfusion group. The decreasing effect was more prominent in melatonin group. The muscle tissue MDA concentration is significantly lower in melatonin group than in ischemia-reperfusion group. The results show that melatonin prevents and improves ischemia-reperfusion injury more effectively in a rat hind limb than DMSO dose. Thus, clinically the melatonin may be used for a beneficial treatment of such injuries