52 research outputs found

    The Effects of the KCNQ Openers Retigabine and Flupirtine on Myotonia in Mammalian Skeletal Muscle Induced by a Chloride Channel Blocker

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    The purpose of this study was to investigate the effect of KCNQ (potassium channel, voltage-gated, KQT-like subfamily) openers in preventing myotonia caused by anthracene-9-carboxylic acid (9-AC, a chloride channel blocker). An animal model of myotonia can be elicited in murine skeletal muscle by 9-AC treatment. KCNQ openers, such as retigabine and flupirtine, can inhibit the increased twitch amplitude (0.1 Hz stimulation) and reduce the tetanic fade (20 Hz stimulations) observed in the presence of 9-AC. Furthermore, the prolonged twitch duration of skeletal muscle was also inhibited by retigabine or flupirtine. Lamotrigine (an anticonvulsant drug) has a lesser effect on the muscle twitch amplitude, tetanic fade, and prolonged twitch duration as compared with KCNQ openers. In experiments using intracellular recordings, retigabine and flupirtine clearly reduced the firing frequencies of repetitive action potentials induced by 9-AC. These data suggested that KCNQ openers prevent the myotonia induced by 9-AC, at least partly through enhancing potassium conductance in skeletal muscle. Taken together, these results indicate that KCNQ openers are potential alternative therapeutic agents for the treatment of myotonia

    The Relationship between Stasis-Stagnation Constitution and Peripheral Arterial Disease in Patients with Type 2 Diabetes

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    Objectives. In traditional Chinese medicine, Yu-Zhi (YZ, indicating stasis and stagnation) constitution describes a body that tends to express abnormal circulatory conditions. This study identified the linkage between YZ constitution and peripheral arterial disease (PAD) in patients with type 2 diabetes. Methods. Patients over 20 years of age who had had type 2 diabetes for 5 years or longer were recruited. PAD was diagnosed if the ankle-brachial index score was ≤0.9 in either leg. Level of YZ constitution was accessed by an YZ Constitution Questionnaire. Results. A total of 712 patients (354 men and 358 women) with a mean age of 61.5±10.6 years and diabetes duration of 13.1±6.7 years were recruited. The prevalence of PAD among our patients was 7.2%. Multivariate logistic regression revealed significant correlations between PAD and, respectively, YZ score, age, diabetes duration, current smoking, and hs-CRP. Conclusion. In addition to traditional risk factors, YZ constitution was statistically associated with PAD in patients with type 2 diabetes. This result invites further research into the effectiveness of traditional Chinese medicine to treat YZ constitution

    Induction of Apoptosis by 11-Dehydrosinulariolide via Mitochondrial Dysregulation and ER Stress Pathways in Human Melanoma Cells

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    In this study the isolated compound 11-dehydrosinulariolide from soft coral Sinularia leptoclados possessed anti-proliferative, anti-migratory and apoptosis-inducing activities against A2058 melanoma cells. Anti-tumor effects of 11-dehydrosinulariolide were determined by MTT assay, cell migration assay and flow cytometry. Growth and migration of melanoma cells were dose-dependently inhibited by 2–8 μg/mL 11-dehydrosinulariolide. Flow cytometric data indicated that 11-dehydrosinulariolide induces both early and late apoptosis in melanoma cells. It was found that the apoptosis induced by 11-dehydrosinulariolide is relevant to mitochondrial-mediated apoptosis via caspase-dependent pathways, elucidated by loss of mitochondrial membrane potential (∆Ym), release of cytochrome C, activation of caspase-3/-9 and Bax as well as suppression of Bcl-2/Bcl-xL. The cleavage of PARP-1 suggested partial involvement of caspase-independent pathways. Immunoblotting data displayed up-regulations of PERK/eIF2α/ATF4/CHOP and ATF6/CHOP coupling with elevation of ER stress chaperones GRP78, GRP94, calnexin, calreticulin and PDI, implicating the involvement of these factors in ER stress-mediated apoptosis induced by 11-dehydrosinulariolide. The abolishment of apoptotic events after pre-treatment with salubrinal indicated that ER stress-mediated apoptosis is also induced by 11-dehydrosinulariolide against melanoma cells. The data in this study suggest that 11-dehydrosinulariolide potentially induces apoptosis against melanoma cells via mitochondrial dysregulation and ER stress pathways

    Flaccidoxide-13-Acetate-Induced Apoptosis in Human Bladder Cancer Cells is through Activation of p38/JNK, Mitochondrial Dysfunction, and Endoplasmic Reticulum Stress Regulated Pathway

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    Flaccidoxide-13-acetate, an active compound isolated from cultured-type soft coral Sinularia gibberosa, has been shown to have inhibitory effects against invasion and cell migration of RT4 and T24 human bladder cancer cells. In our study, we used an 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation assay, and flow cytometry to determine the mechanisms of the anti-tumor effect of flaccidoxide-13-acetate. The MTT and colony formation assays showed that the cytotoxic effect of flaccidoxide-13-acetate on T24 and RT4 cells was dose-dependent, and the number of colonies formed in the culture was reduced with increasing flaccidoxide-13-acetate concentration. Flow cytometry analysis revealed that flaccidoxide-13-acetate induced late apoptotic events in both cell lines. Additionally, we found that flaccidoxide-13-acetate treatment upregulated the expressions of cleaved caspase 3, cleaved caspase 9, Bax, and Bad, and down-regulated the expressions of Bcl-2, p-Bad, Bcl-x1, and Mcl-1. The results indicated that apoptotic events were mediated by mitochondrial dysfunction via the caspase-dependent pathway. Flaccidoxide-13-acetate also provoked endoplasmic reticulum (ER) stress and led to activation of the PERK-eIF2α-ATF6-CHOP pathway. Moreover, we examined the PI3K/AKT signal pathway, and found that the expressions of phosphorylated PI3K (p-PI3K) and AKT (p-AKT) were decreased with flaccidoxide-13-acetate concentrations. On the other hand, our results showed that the phosphorylated JNK and p38 were obviously activated. The results support the idea that flaccidoxide-13-acetate-induced apoptosis is mediated by mitochondrial dysfunction, ER stress, and activation of both the p38 and JNK pathways, and also relies on inhibition of PI3K/AKT signaling. These findings imply that flaccidoxide-13-acetate has potential in the development of chemotherapeutic agents for human bladder cancer

    Cichoric Acid May Play a Role in Protecting Hair Cells from Ototoxic Drugs

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    Ototoxic hearing loss due to antibiotic medication including aminoglycosides and excess free radical production causes irreversible hair cell injury. Cichoric acid, a naturally occurring phenolic acid, has recently been found to exert anti-oxidative and anti-inflammatory properties through its free radical scavenging capacity. The present study aimed to investigate the protective effects of cichoric acid against neomycin-induced ototoxicity using transgenic zebrafish (pvalb3b: TagGFP). Our results indicated that cichoric acid in concentrations up to 5 μM did not affect zebrafish viability during the 2 h treatment period. Therefore, the otoprotective concentration of cichoric acid was identified as 5 μM under 2 h treatment by counting viable hair cells within the neuromasts of the anterior- and posterior-lateral lines in the study. Pretreatment of transgenic zebrafish with 5 μM of cichoric acid for 2 h significantly protected against neomycin-induced hair cell death. Protection mediated by cichoric acid was, however, lost over time. A terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and FM4-64 staining, respectively, provided in situ evidence that cichoric acid ameliorated apoptotic signals and mechanotransduction machinery impairment caused by neomycin. A fish locomotor test (distance move, velocity, and rotation frequency) assessing behavioral alteration after ototoxic damage revealed rescue due to cichoric acid pretreatment before neomycin exposure. These findings suggest that cichoric acid in 5 μM under 2 h treatment has antioxidant effects and can attenuate neomycin-induced hair cell death in neuromasts. Although cichoric acid offered otoprotection, there is only a small difference between pharmacological and toxic concentrations, and hence cichoric acid can be considered a rather prototypical compound for the development of safer otoprotective compounds

    IoT for Environmental Management and Security Governance: An Integrated Project in Taiwan

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    Taiwan is in a hazard-exposed area where people often suffer through typhoons, earthquakes, and landslides, and must face the challenges of environmental and climate changes in ongoing and future developments. Taiwan has implemented an integrated and interdisciplinary project, which is titled Civil IoT Taiwan, for better disaster risk management and risk communication with all stakeholders by cooperating closely with authorities, scientists, and industry. The purposes of this project are to raise public risk awareness to reduce disaster damage and loss and sustainably increase the social, economic, and environmental impacts. For measuring the social impacts of the Civil IoT Taiwan, the social return on investment (SROI) is an evaluation tool to demonstrate the outcomes and impacts of Civil IoT Taiwan to measure its social effects. The SROI ratio of this project is 1.12. Civil IoT Taiwan has just implemented the first development stage in establishing infrastructure for monitoring and sensing; thus, the significant changes and impacts on society, economics, and the environment will be evaluated in the next phase. This ongoing project will also involve more stakeholders for more sustainable and resilient environmental governance in future development

    The Functional Role of CONNEXIN 26 Mutation in Nonsyndromic Hearing Loss, Demonstrated by Zebrafish Connexin 30.3 Homologue Model

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    Nonsyndromic hearing loss (NSHL) is of great clinical importance, and mutations in the GJB2 gene and the encoded human CONNEXIN 26 (CX26) protein play important roles in the genetic pathogenesis. The CX26 p.R184Q mutation was shown to be a dominant-negative effect in our previous study. Previously, we also demonstrated that zebrafish Cx30.3 is orthologous to human CX26. In the present study, we established transgenic zebrafish models with mutated Cx30.3 specifically expressed in the supporting cells of zebrafish inner ears driven by the agr2 promoter, to demonstrate and understand the mechanism by which the human CX26 R.184 mutation causes NSHL. Our results indicated that significant structural changes in the inner ears of transgenic lines with mutations were measured and compared to wild-type zebrafish. Simultaneously, significant alterations of transgenic lines with mutations in swimming behavior were analyzed with the zebrafish behavioral assay. This is the first study to investigate the functional results of the CX26 p.R184Q mutation with in vivo disease models. Our work supports and confirms the pathogenic role of the CX26 p.R184Q mutation in NSHL, with a hypothesized mechanism of altered interaction among amino acids in the connexins

    Flaccidoxide-13-Acetate Extracted from the Soft Coral Cladiella kashmani Reduces Human Bladder Cancer Cell Migration and Invasion through Reducing Activation of the FAK/PI3K/AKT/mTOR Signaling Pathway

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    Metastasis of cancer is the cause of the majority of cancer deaths. Active compound flaccidoxide-13-acetate, isolated from the soft coral Cladiella kashmani, has been found to exhibit anti-tumor activity. In this study, Boyden chamber analysis, Western blotting and gelatin zymography assays indicated that flaccidoxide-13-acetate exerted inhibitory effects on the migration and invasion of RT4 and T24 human bladder cancer cells. The results demonstrated that flaccidoxide-13-acetate, in a concentration-dependent manner, reduced the levels of matrix metalloproteinase-2 (MMP-2), MMP-9, urokinase-type plasminogen activator receptor (uPAR), focal adhesion kinase (FAK), phosphatidylinositide-3 kinases (PI3K), p-PI3K, AKT, p-AKT, mammalian target of rapamycin (mTOR), p-mTOR, Ras homolog gene family, member A (Rho A), Ras, mitogen-activated protein kinase kinase 7 (MKK7) and mitogen-activated protein kinase kinase kinase 3 (MEKK3), and increased the expressions of tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 in RT4 and T24 cells. This study revealed that flaccidoxide-13-acetate suppressed cell migration and invasion by reducing the expressions of MMP-2 and MMP-9, regulated by the FAK/PI3K/AKT/mTOR pathway. In conclusion, our study was the first to demonstrate that flaccidoxide-13-acetate could be a potent medical agent for use in controlling the migration and invasion of bladder cancer
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