150 research outputs found

    ROCK inhibitor, Y-27632, reduces FBS-induced structural alteration in organ-cultured mesenteric artery

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    Background Chronic treatment with fetal bovine serum (FBS) causes gradual vasoconstriction, vascular wall thickening, and contractility reduction in organ-cultured vascular tissues. We have previously demonstrated that Rho-associated kinase (ROCK) inhibitors prevent the functional alterations of small arteries in response to the FBS treatment. Here, we tested a further hypothesis that the chronic inhibition of ROCK has a protective effect on FBS-induced structural alterations. Methods To verify the new hypothesis, the rabbit mesenteric arterial rings were cultured in FBS-supplemented culture medium with or without Y-27632, a reversible ROCK inhibitor and then western blot, immunohistochemistry, apoptosis assay, and electron microscopy were performed using organ-cultured arterial rings. Results Chronic treatment with Y-27632 maintained the arterial diameter by preventing FBS-induced gradual arterial constriction during organ culture. Y-27632 also reduced the apoptosis and the loss of contractile myosin and actin filaments of smooth muscle cells. In addition, Y-27632 protected the morphological integrity between the endothelial cell layer and smooth muscle cell layer by preventing endothelial cell detachment and platelet endothelial cell adhesion molecule (PECAM) expression decrement. Conclusions Chronic ROCK inhibition provides protective effects against FBS-stimulated structural in addition to functional alterations of vascular smooth muscle cells and endothelial cells. These results strongly suggest that the RhoA/ROCK signaling is crucial for maintaining the structural and functional phenotypes of vasculature, and hence, chronic ROCK inhibition may provide protective effects on excessive growth factor-related vascular diseases including hypertension and atherosclerosis

    A general algorithm for limit solutions of plane stress problems

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    A computational approach to limit solutions is considered most challenging for two major reasons. A limit solution is likely to be non-smooth such that certain non-differentiable functions are perfectly admissible and make physical and mathematical sense. Moreover, the possibility of non-unique solutions makes it difficult to analyze the convergence of an iterative algorithm or even to define a criterion of convergence. In this paper, we use two mathematical tools to resolve these difficulties. A duality theorem defines convergence from above and from below the exact solution. A combined smoothing and successive approximation applied to the upper bound formulation perturbs the original problem into a smooth one by a small parameter [var epsilon]. As [var epsilon] --> 0, the solution of the original problem is recovered. This general computational algorithm is robust such that from any initial trial solution, the first iteration falls into a convex hull that contains the exact solution(s) of the problem. Unlike an incremental method thut invariably renders the limit problem ill-conditioned, the algorithm is numerically stable. Limit analysis itself is a highly efficient concept which bypasses the tedium of the intermediate elastic-plastic deformation and seeks the most important information directly. With the said algorithm, we have produced many limit solutions of plane stress problems. Certain non-smooth characters of the limit solutions are shown in the examples presented. Two well-known as well as one parametric family of yield functions are used to allow comparison with some classical solutions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29642/1/0000731.pd

    Cordycepin inhibits human ovarian cancer by inducing autophagy and apoptosis through Dickkopf-related protein 1/β-catenin signaling

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    Cordycepin, the major active component from Cordyceps militaris, has been reported to significantly inhibit some types of cancer; however, its effects on ovarian cancer are still not well understood. In this study, we treated human ovarian cancer cells with different doses of cordycepin and found that it dose-dependently reduced ovarian cancer cell viability, based on Cell counting kit-8 reagent. Immunoblotting showed that cordycepin increased Dickkopf-related protein 1 (Dkk1) levels and inhibited β-catenin signaling. Atg7 knockdown in ovarian cancer cells significantly inhibited cordycepin-induced apoptosis, whereas β-catenin overexpression abolished the effects of cordycepin on cell death and proliferation. Furthermore, we found that Dkk1 overexpression by transfection downregulated the expression of c-Myc and cyclin D1. siRNA-mediated Dkk1 silencing downregulated the expression of Atg8, beclin, and LC3 and promoted β-catenin translocation from the cytoplasm into the nucleus. These results suggest that cordycepin inhibits ovarian cancer cell growth, possibly through coordinated autophagy and Dkk1/β-catenin signaling. Taken together, our findings provide new insights into the treatment of ovarian cancer using cordycepin

    Junctional membrane inositol 1,4,5-trisphosphate receptor complex coordinates sensitization of the silent EGF-induced Ca2+ signaling

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    Ca2+ is a highly versatile intracellular signal that regulates many different cellular processes, and cells have developed mechanisms to have exquisite control over Ca2+ signaling. Epidermal growth factor (EGF), which fails to mobilize intracellular Ca2+ when administrated alone, becomes capable of evoking [Ca2+]i increase and exocytosis after bradykinin (BK) stimulation in chromaffin cells. Here, we provide evidence that this sensitization process is coordinated by a macromolecular signaling complex comprised of inositol 1,4,5-trisphosphate receptor type I (IP3R1), cAMP-dependent protein kinase (PKA), EGF receptor (EGFR), and an A-kinase anchoring protein, yotiao. The IP3R complex functions as a focal point to promote Ca2+ release in two ways: (1) it facilitates PKA-dependent phosphorylation of IP3R1 in response to BK-induced elevation of cAMP, and (2) it couples the plasmalemmal EGFR with IP3R1 at the Ca2+ store located juxtaposed to the plasma membrane. Our study illustrates how the junctional membrane IP3R complex connects different signaling pathways to define the fidelity and specificity of Ca2+ signaling

    Successful Chemotherapy Following Autologous Stem Cell Transplantation in Multiple Myeloma and Multi-organ Dysfunction with Infiltration of Eosinophils: A Case Report

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    Eosinophils are derived from hematopoietic stem cells. Peripheral blood eosinophilia is defined as an absolute eosinophil count of ≥0.5×109/L. Eosinophilia is classified into primary or clonal eosinophilia, secondary eosinophilia, and idiopathic categories including idiopathic hypereosinophilic syndrome. Both hematopoietic and solid neoplasms may be associated with peripheral blood eosinophilia, but multiple myeloma is rarely associated with eosinophilia. We now report the case of a 31-year-old man with multiple myeloma associated with marked eosinophilia who developed multiple organ dysfunction with infiltration of eosinophils. He recovered after treatment with chemotherapy followed by autologous stem cell transplantation

    The Evolutionarily Conserved LIM Homeodomain Protein LIM-4/LHX6 Specifies the Terminal Identity of a Cholinergic and Peptidergic C. elegans Sensory/Inter/Motor Neuron-Type

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    The expression of specific transcription factors determines the differentiated features of postmitotic neurons. However, the mechanism by which specific molecules determine neuronal cell fate and the extent to which the functions of transcription factors are conserved in evolution are not fully understood. In C. elegans, the cholinergic and peptidergic SMB sensory/inter/motor neurons innervate muscle quadrants in the head and control the amplitude of sinusoidal movement. Here we show that the LIM homeobox protein LIM-4 determines neuronal characteristics of the SMB neurons. In lim-4 mutant animals, expression of terminal differentiation genes, such as the cholinergic gene battery and the flp-12 neuropeptide gene, is completely abolished and thus the function of the SMB neurons is compromised. LIM-4 activity promotes SMB identity by directly regulating the expression of the SMB marker genes via a distinct cis-regulatory motif. Two human LIM-4 orthologs, LHX6 and LHX8, functionally substitute for LIM-4 in C. elegans. Furthermore, C. elegans LIM-4 or human LHX6 can induce cholinergic and peptidergic characteristics in the human neuronal cell lines. Our results indicate that the evolutionarily conserved LIM-4/LHX6 homeodomain proteins function in generation of precise neuronal subtypes

    The Effects of Short-duration Exercise on Arterial Stiffness in Patients with Stable Coronary Artery Disease

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    Arterial stiffness is an important contributor to the development of cardiovascular disease. We investigated the effect of short duration exercise using the treadmill test on arterial stiffness in the presence of coronary artery disease. We enrolled patients with and without coronary artery diseases (CAD and control group, 50 patients each) referred for treadmill testing. Brachial-ankle pulse wave velocity (baPWV) were measured before and after treadmill testing. Values of baPWV were significantly reduced at 10 min after exercise in both groups, more in the CAD group than in the control group (baseline baPWV and post-exercise change [cm/sec]: 1,527±245 and -132±155 in the CAD group, 1,439±202 and -77±93 in the control group, respectively, P for change in each group <0.001, P for difference in changes between the two groups <0.001). These findings persisted after adjusting for age, body mass index, systolic blood pressure, mean arterial pressure (MAP), MAP decreases, and baseline baPWV. Significant post-exercise baPWV reductions were observed in both groups, and more prominently in the CAD group. This finding suggests that short-duration exercise may effectively improve arterial stiffness even in patients with stable coronary artery disease

    KNOW-KT (KoreaN cohort study for outcome in patients with kidney transplantation: a 9-year longitudinal cohort study): study rationale and methodology

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    BACKGROUND: Asian patients undergoing kidney transplantation (KT) generally have better renal allograft survival and a lower burden of cardiovascular disease than those of other racial groups. The KNOW-KT aims to explore allograft survival rate, cardiovascular events, and metabolic profiles and to elucidate the risk factors in Korean KT patients. METHODS: KNOW-KT is a multicenter, observational cohort study encompassing 8 transplant centers in the Republic of Korea. KNOW-KT will enroll 1,000 KT recipients between 2012 and 2015 and follow them up to 9 years. At the time of KT and at pre-specified intervals, clinical information, laboratory test results, and functional and imaging studies on cardiovascular disease and metabolic complications will be recorded. Comorbid status will be assessed by the age-adjusted Charlson co-morbidity index. Medication adherence and information on quality of life (QoL) will be monitored periodically. The QoL will be assessed by the Kidney Disease Quality of Life Short Form. Donors will include both living donors and deceased donors whose status will be assessed by the Kidney Donor Risk Index. Primary endpoints include graft loss and patient mortality. Secondary endpoints include renal functional deterioration (a decrease in eGFR to <30 mL/min/1.73 m(2)), acute rejection, cardiovascular event, albuminuria, new-onset diabetes after transplant, and QoL. Data on other adverse outcomes including episodes of infection, malignancy, recurrence of original renal disease, fracture, and hospitalization will also be collected. A bio-bank has been established for the acquisition of DNA, RNA, and protein from serum and urine samples of recipients at regular intervals. Bio-samples from donors will also be collected at the time of KT. KNOW-KT was registered in an international clinical trial registry (NCT02042963 at http://www.clinicaltrials.gov) on January 20(th), 2014. CONCLUSION: The KNOW-KT, the first large-scale cohort study in Asian KT patients, is expected to represent the Asian KT population and provide information on their natural course, complications, and risk factors for complications

    Autophagy pathway upregulation in a human iPSC-derived neuronal model of Cohen syndrome with VPS13B missense mutations

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    Significant clinical symptoms of Cohen syndrome (CS), a rare autosomal recessive disorder, include intellectual disability, facial dysmorphism, postnatal microcephaly, retinal dystrophy, and intermittent neutropenia. CS has been associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, which regulates vesicle-mediated protein sorting and transport; however, the cellular mechanism underlying CS pathogenesis in patient-derived neurons remains uncertain. This report states that autophagic vacuoles accumulate in CS fibroblasts and the axonal terminals of CS patient-specific induced pluripotent stem cells (CS iPSC)-derived neurons; additionally, autophagic flux was significantly increased in CS-derived neurons compared to control neurons. VPS13B knockout HeLa cell lines generated using the CRISPR/Cas9 genome editing system showed significant upregulation of autophagic flux, indicating that VSP13B may be associated with autophagy in CS. Transcriptomic analysis focusing on the autophagy pathway revealed that genes associated with autophagosome organization were dysregulated in CS-derived neurons. ATG4C is a mammalian ATG4 paralog and a crucial regulatory component of the autophagosome biogenesis/recycling pathway. ATG4C was significantly upregulated in CS-derived neurons, indicating that autophagy is upregulated in CS neurons. The autophagy pathway in CS neurons may be associated with the pathophysiology exhibited in the neural network of CS patients.This work was supported by National Research Foundation (NRF2017R1D1A3B03030972), the National Honor Scientist Program, the Korea Health Technology R&D Project (HI18C0158), and the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Ministry of Science & ICT (2017M3A9G7073521) to J.-A L
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