180 research outputs found

    Comparisons of ELISA and Western blot assays for detection of autophagy flux

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    We analyzed autophagy/mitophagy flux in vitro (C2C12 myotubes) and in vivo (mouse skeletal muscle) following the treatments of autophagy inducers (starvation, rapamycin) and a mitophagy inducer (carbonyl cyanide m-chlorophenylhydrazone, CCCP) using two immunodetection methods, ELISA and Western blotting, and compared their working range, accuracy, and reliability. The ELISAs showed a broader working range than that of the LC3 Western blots (Table 1). Table 2 showed that data value distribution was tighter and the average standard error from the ELISA was much smaller than those of the Western blot, directly relating to the accuracy of the assay. Test-retest reliability analysis showed good reliability for three individual ELISAs (interclass correlation, ≥ 0.7), but poor reliability for three individual Western blots (interclass correlation, ≤ 0.4) (Table 3). Keywords: Autophagy, Mitophagy, ELISA, Western blot, Skeletal muscl

    Grape seed proanthocyanidin extract inhibits glutamate-induced cell death through inhibition of calcium signals and nitric oxide formation in cultured rat hippocampal neurons

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    <p>Abstract</p> <p>Background</p> <p>Proanthocyanidin is a polyphenolic bioflavonoid with known antioxidant activity. Some flavonoids have a modulatory effect on [Ca<sup>2+</sup>]<sub>i</sub>. Although proanthocyanidin extract from blueberries reportedly affects Ca<sup>2+ </sup>buffering capacity, there are no reports on the effects of proanthocyanidin on glutamate-induced [Ca<sup>2+</sup>]<sub>i </sub>or cell death. In the present study, the effects of grape seed proanthocyanidin extract (GSPE) on glutamate-induced excitotoxicity was investigated through calcium signals and nitric oxide (NO) in cultured rat hippocampal neurons.</p> <p>Results</p> <p>Pretreatment with GSPE (0.3-10 μg/ml) for 5 min inhibited the [Ca<sup>2+</sup>]<sub>i </sub>increase normally induced by treatment with glutamate (100 μM) for 1 min, in a concentration-dependent manner. Pretreatment with GSPE (6 μg/ml) for 5 min significantly decreased the [Ca<sup>2+</sup>]<sub>i </sub>increase normally induced by two ionotropic glutamate receptor agonists, N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). GSPE further decreased AMPA-induced response in the presence of 1 μM nimodipine. However, GSPE did not affect the 50 mM K<sup>+</sup>-induced increase in [Ca<sup>2+</sup>]<sub>i</sub>. GSPE significantly decreased the metabotropic glutamate receptor agonist (<it>RS</it>)-3,5-Dihydroxyphenylglycine-induced increase in [Ca<sup>2+</sup>]<sub>i</sub>, but it did not affect caffeine-induced response. GSPE (0.3-6 μg/ml) significantly inhibited synaptically induced [Ca<sup>2+</sup>]<sub>i </sub>spikes by 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>. In addition, pretreatment with GSPE (6 μg/ml) for 5 min inhibited 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>- and glutamate-induced formation of NO. Treatment with GSPE (6 μg/ml) significantly inhibited 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>- and oxygen glucose deprivation-induced neuronal cell death.</p> <p>Conclusions</p> <p>All these data suggest that GSPE inhibits 0.1 mM [Mg<sup>2+</sup>]<sub>o</sub>- and oxygen glucose deprivation-induced neurotoxicity through inhibition of calcium signals and NO formation in cultured rat hippocampal neurons.</p

    Altered expression of thioredoxin reductase-1 in dysplastic bile ducts and cholangiocarcinoma in a hamster model

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    Thioredoxin reductase 1 (TrxR) is a homodimeric selenoenzyme catalyzing thioredoxin (Trx) in an NADPHdependent manner. With regard to carcinogenesis, these redox proteins have been implicated in cell proliferation, transformation and anti-apoptosis. In the present study, using a hamster cholangiocarcinoma (ChC) model, we evaluated the immunohistochemical expression pattern of TrxR in precancerous lesions and ChCs as well as in normal bile ducts. The goal of this study was to determine the potential role and importance of TrxR in cholangiocarcinogenesis. For the ChC model, we obtained liver tissue specimens with dysplastic bile ducts prior to the development of ChC 8 weeks after initiation of the experiment and ChC samples at 27 weeks. The immunohistochemical analysis showed diffuse cytoplasmic overexpression of TrxR in the dysplastic bile duct epithelial cells as well as in cholangiocarcinoma; this was comparable to the negative or weakly positive in normal and type 1 hyperplastic bile ducts. However, TrxR appeared to be considerably down-regulated in the ChCs when compared to the higher expression observed in the dysplastic bile ducts. Therefore, these results suggest that TrxR overexpression followed by down-regulation might be an important event in cholangiocarcinogenesis, especially at early stages including the cellular transformation of candidate bile ducts. Further studies are however required to determine whether TrxR may be a potential target molecule for chemoprevention against cholangiocarcinogenesis. In addition, the molecular mechanism as well as the importance of the loss of TrxR in the development of cholangiocarcinoma, following dysplastic transformation of bile duct cells, also remains to be clarified.This study was supported by Kangwon National University and Korea Research Foundation Grant (KRF-2004-041- E00324). The authors wish to thank Dr. Min-Ho Choi, College of Medicine, Seoul National University, for providing Clonorchis sinensis

    High white blood cell count and erythrocyte sedimentation rate are associated with perforated appendicitis in children

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    Purpose To investigate the predictors of perforated appendicitis (PA) in pediatric patients with appendicitis seen in the emergency department. Methods We retrospectively reviewed 564 pediatric patients ( 13.5 × 109/L (odds ratio [OR], 3.27; confidence interval [CI], 1.49-7.18; P = 0.003) and ESR > 15 mm/h (OR, 3.18; 95% CI, 2.13-4.74; P < 0.001) are independent predictors of PA. Conclusion WBC count and ESR might be better predictors of PA in pediatric patients with appendicitis in the emergency department than the Alvarado score and CRP concentration

    Factors associated with administration of analgesics for children with forearm fracture

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    Purpose Analgesia is essential for the treatment of children’s fracture. We aimed to investigate the factors associated with administration of analgesics in children with forearm fracture. Methods We retrospectively reviewed medical records of children (< 20 years) with forearm fracture who visited 2 tertiary hospital emergency departments from 2014 to 2015. We analyzed factors, such as gender, age, whether the mother accompanied the visit, visiting time and route, mechanism of injury, duration of symptoms, complicated fracture, manual reduction, surgery, and type and route of analgesics. We also performed logistic regression analysis to identify the factors associated with administration of analgesics. Results Of 179 children with forearm fracture, 48 (26.8%) were administered analgesics. These children showed older age, shorter duration of symptoms, and more frequent visit with their mothers, visit during the day, use of emergency medical services, and surgery. After logistic regression analysis, we found use of emergency medical service (adjusted odds ratio [OR], 8.73; 95% confidence interval [CI], 3.16-24.08; P < 0.001), visit with the mother (OR, 6.23; 95% CI, 1.68-23.09; P = 0.006), age (OR, 1.18; 95% CI, 1.05-1.32; P = 0.004), and duration of symptoms (OR, 0.99; 95% CI, 0.986-0.999; P = 0.035) as the factors associated with administration of analgesics. Conclusion The factors associated with administration of analgesics might be communicating skill-related factors, such as older age and shorter duration of symptoms. Children with poor communicating skill may need more aggressive analgesia in the emergency department

    Electrochemical Properties of Chemically Processed SiO

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    A SiOx coating material for Si anode in lithium-ion battery was processed by using SiCl4 and ethylene glycol. The produced SiOx particles after heat treatment at 725°C for 1 h were porous and irregularly shaped with amorphous structure. Pitch carbon added to SiOx was found to strongly affect solid electrolyte interphase stabilization and cyclic stability. When mixed with an optimal amount of 30 wt% pitch carbon, the SiOx showed a high charge/discharge cyclic stability of about 97% for the 2nd to the 50th cycle. The initial specific capacity of the SiOx was measured to be 1401 mAh/g. On the basis of the evaluation of the SiOx coating material, the process utilized in this study is considered an efficient method to produce SiOx with high performance in an economical way

    Pediatricians and Emergency Physicians’ Recognition and Training Regarding Child Abuse

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    Purpose To explore the recognition levels and educational experiences of child abuse among physicians. Methods We conducted an electronic questionnaire survey of pediatricians and emergency physicians. Results Of the 245 total respondents, 63% remarked that child abuse occurred “frequently” in Korea. One hundred twenty-seven (51.8%) respondents experienced an abused child during their practice, and only 55.9% reported the event. Regarding the knowledge for obligation of report as a medical specialist, 45.7% knew where they should report the case, and 39.2% of the respondents knew the phone number of the “Child Protection Agency”. Most respondents (70.2%) answered that they had never received an education about child abuse. Some respondents answered that they had not reported a suspected abused case because they were not certain that the case was abuse and thereby felt discomfort in making the report. To enhance child abuse reports, respondents thought that an immediate intervention is necessary for the reported case. Also, they answered that their confidentialities have to be assured and that the education about child abuse is needed. Conclusion The survey results show that pediatricians and emergency physicians often do not report suspected abuse despite their suspicion of the seriousness and frequent occurrence of child abuse. Such behaviors are affected by the recognition and knowledge levels about child abuse, the experience of training for child abuse, and discomfort of the reporting process. For medical specialists’ attention and reporting of abuse, repetitive education, appropriate public relations and improvement of the reporting process are needed

    The Characteristics of Metallo-β-Lactamase-Producing Gram-Negative Bacilli Isolated from Sputum and Urine: A Single Center Experience in Korea

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    Metallo-β-lactamase (MBL) production usually results in high-level resistance to most β-lactams, and a rapid spread of MBL producing major gram-negative pathogens is a matter of particular concern worldwide. However, clinical data are scarce and most studies compared MBL producer (MP) with MBL non-producer (MNP) strains which included carbapenem susceptible isolates. Therefore, we collected clinical data of patients in whom imipenem-nonsusceptible Pseudomonas aeruginosa (PA) and Acinetobacter baumannii (AB) were isolated from sputum or urine, and investigated MBL production and the risk factors related with MBL acquisition. The antimicrobial susceptibility patterns were also compared between MPs and imipenem-nonsusceptible MNPs (INMNP). Among the 176 imipenem-nonsusceptible isolates, 12 MPs (6.8%) were identified. There was no identifiable risk factor that contributed to the acquisition of MPs when compared to INMNPs, and case-fatalities were not different between the two groups. The percentage of susceptible isolates was higher among MPs for piperacilin/tazobactam and fluoroquinolones while that of ceftazidime was higher in INMNPs (p < 0.05). As regards to aztreonam, which has been known to be a uniquely stable β-lactam against MBLs, susceptibility was preserved in only two isolates (16.7%) among MPs, and was not higher than that of INMNPs (23.2%). In conclusion, the contribution of MBLs to imipenem non-susceptibility in PA/ABs isolated from sputum and urine was relatively limited, and there was no significant risk factor associated with acquisition of MPs compared with INMNPs. However, limited susceptibility to aztreonam implies that MPs may hold additional resistance mechanisms, such as extended spectrum β-lactamases, AmpC β-lactamases, or other non-enzymatic mechanisms

    Altered expression of thioredoxin reductase-1 in dysplastic bile ducts and cholangiocarcinoma in a hamster model

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    Thioredoxin reductase 1 (TrxR) is a homodimeric selenoenzyme catalyzing thioredoxin (Trx) in an NADPH-dependent manner. With regard to carcinogenesis, these redox proteins have been implicated in cell proliferation, transformation and anti-apoptosis. In the present study, using a hamster cholangiocarcinoma (ChC) model, we evaluated the immunohistochemical expression pattern of TrxR in precancerous lesions and ChCs as well as in normal bile ducts. The goal of this study was to determine the potential role and importance of TrxR in cholangiocarcinogenesis. For the ChC model, we obtained liver tissue specimens with dysplastic bile ducts prior to the development of ChC 8 weeks after initiation of the experiment and ChC samples at 27 weeks. The immunohistochemical analysis showed diffuse cytoplasmic overexpression of TrxR in the dysplastic bile duct epithelial cells as well as in cholangiocarcinoma; this was comparable to the negative or weakly positive in normal and type 1 hyperplastic bile ducts. However, TrxR appeared to be considerably down-regulated in the ChCs when compared to the higher expression observed in the dysplastic bile ducts. Therefore, these results suggest that TrxR overexpression followed by down-regulation might be an important event in cholangiocarcinogenesis, especially at early stages including the cellular transformation of candidate bile ducts. Further studies are however required to determine whether TrxR may be a potential target molecule for chemoprevention against cholangiocarcinogenesis. In addition, the molecular mechanism as well as the importance of the loss of TrxR in the development of cholangiocarcinoma, following dysplastic transformation of bile duct cells, also remains to be clarified
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