1,112 research outputs found

    Structural Simplification of Bedaquiline: the Discovery of 3-(4-(N,N-dimethylaminomethyl)phenyl)quinoline Derived Antitubercular Lead Compounds

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    Bedaquiline (BDQ) is a novel and highly potent last-line antituberculosis drug that was approved by the US FDA in 2013. Owing to its stereo-structural complexity, chemical synthesis and compound optimization are rather difficult and expensive. This study describes the structural simplification of bedaquiline while preserving antitubercular activity. The compound's structure was split into fragments and reassembled in various combinations while replacing the two chiral carbon atoms with an achiral linkage instead. Four series of analogues were designed; these candidates retained their potent antitubercular activity at sub-microgram per mL concentrations against both sensitive and multidrug-resistant (MDR) Mycobacterium tuberculosis strains. Six out of the top nine MIC-ranked candidates were found to inhibit mycobacterial ATP synthesis activity with IC50 values between 20 and 40 μm, one had IC50>66 μm, and two showed no inhibition, despite their antitubercular activity. These results provide a basis for the development of chemically less complex, lower-cost bedaquiline derivatives and describe the identification of two derivatives with antitubercular activity against non-ATP synthase related targets

    Early and late effects of the DPP-4 inhibitor vildagliptin in a rat model of post-myocardial infarction heart failure

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    <p>Abstract</p> <p>Background</p> <p>Progressive remodeling after myocardial infarction (MI) is a leading cause of morbidity and mortality. Recently, glucagon-like peptide (GLP)-1 was shown to have cardioprotective effects, but treatment with GLP-1 is limited by its short half-life. It is rapidly degraded by the enzyme dipeptidyl peptidase-4 (DPP-4), an enzyme which inhibits GLP-1 activity. We hypothesized that the DPP-4 inhibitor vildagliptin will increase levels of GLP-1 and may exert protective effects on cardiac function after MI.</p> <p>Methods</p> <p>Sprague-Dawley rats were either subjected to coronary ligation to induce MI and left ventricular (LV) remodeling, or sham operation. Parts of the rats with an MI were pre-treated for 2 days with the DPP-4 inhibitor vildagliptin (MI-Vildagliptin immediate, MI-VI, 15 mg/kg/day). The remainder of the rats was, three weeks after coronary artery ligation, subjected to treatment with DPP-4 inhibitor vildagliptin (MI-Vildagliptin Late, MI-VL) or control (MI). At 12 weeks, echocardiography and invasive hemodynamics were measured and molecular analysis and immunohistochemistry were performed.</p> <p>Results</p> <p>Vildagliptin inhibited the DPP-4 enzymatic activity by almost 70% and increased active GLP-1 levels by about 3-fold in plasma in both treated groups (p < 0.05 vs. non-treated groups). Cardiac function (ejection fraction) was decreased in all 3 MI groups compared with Sham group (p < 0.05); treatment with vildagliptin, either early or late, did not reverse cardiac remodeling. ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide) mRNA levels were significantly increased in all 3 MI groups, but no significant reductions were observed in both vildagliptin groups. Vildagliptin also did not change cardiomyocyte size or capillary density after MI. No effects were detected on glucose level and body weight in the post-MI remodeling model.</p> <p>Conclusion</p> <p>Vildagliptin increases the active GLP-1 level via inhibition of DPP-4, but it has no substantial protective effects on cardiac function in this well established long-term post-MI cardiac remodeling model.</p

    Convincing the crowd: entrepreneurial storytelling in crowdfunding campaigns

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    This study examines the structure of entrepreneurial stories in pursuit of mobilizing resources from crowds. Based on a comparative analysis of Kickstarter crowdfunding campaigns, we examine in particular how, across different project types, project histories and potential futures are framed and interlinked in narratives to appeal to funders. We find that projects are narrated in different styles—as ongoing journeys” or “results-inprogress”— to convey project value. The former style narrates projects as longer-term endeavors powered by creative initial ideas and a bold vision, inviting audiences to “join the journey”; the latter narrates projects more narrowly as a progression of accomplishments, engaging the audience instrumentally to support next steps. We find that styles are used and combined in different ways, reflecting the tangibility of project outcomes, the sophistication of technology, and the social orientation of projects. Also, successful differ from unsuccessful campaigns in using narratives more coherently. Findings inform research on narrative processes in entrepreneurship and innovation, and research on the mobilization of crowds

    Co-creation workshops for work life oriented ICT education

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    ICT Companies in Finland today are facing problems in recruiting the right skilled workforce to meet their needs [1]. There is particular shortage of application developers, application designers, web professionals and coders in the South Ostrobothnia area of Finland [2]. Typical degree courses offered by universities would not work because there is a mismatch between the university degrees offered and the needs of these companies. There is a need to develop a new approach to address this shortage. In response to this, local University of Applied Sciences has developed a new ICT education programme using co-creation methods. The new approach is based on the concepts of co-creation of value from service science. This paper discusses the importance of this new approach in education and how it can be implemented. Empirical data is gathered through observation of and reflection on the development of the ICT programme which follows the principles of co-creation

    Stability analysis of mixtures of mutagenetic trees

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    <p>Abstract</p> <p>Background</p> <p>Mixture models of mutagenetic trees are evolutionary models that capture several pathways of ordered accumulation of genetic events observed in different subsets of patients. They were used to model HIV progression by accumulation of resistance mutations in the viral genome under drug pressure and cancer progression by accumulation of chromosomal aberrations in tumor cells. From the mixture models a genetic progression score (GPS) can be derived that estimates the genetic status of single patients according to the corresponding progression along the tree models. GPS values were shown to have predictive power for estimating drug resistance in HIV or the survival time in cancer. Still, the reliability of the exact values of such complex markers derived from graphical models can be questioned.</p> <p>Results</p> <p>In a simulation study, we analyzed various aspects of the stability of estimated mutagenetic trees mixture models. It turned out that the induced probabilistic distributions and the tree topologies are recovered with high precision by an EM-like learning algorithm. However, only for models with just one major model component, also GPS values of single patients can be reliably estimated.</p> <p>Conclusion</p> <p>It is encouraging that the estimation process of mutagenetic trees mixture models can be performed with high confidence regarding induced probability distributions and the general shape of the tree topologies. For a model with only one major disease progression process, even genetic progression scores for single patients can be reliably estimated. However, for models with more than one relevant component, alternative measures should be introduced for estimating the stage of disease progression.</p

    Targeting canine bladder transitional cell carcinoma with a human bladder cancer-specific ligand

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    <p>Abstract</p> <p>Objective</p> <p>To determine if a human bladder cancer-specific peptide named PLZ4 can target canine bladder cancer cells.</p> <p>Experimental Design</p> <p>The binding of PLZ4 to five established canine invasive transitional cell carcinoma (TCC) cell lines and to normal canine bladder urothelial cells was determined using the whole cell binding assay and an affinitofluorescence assay. The WST-8 assay was performed to determine whether PLZ4 affected cell viability. <it>In vivo </it>tumor-specific homing/targeting property and biodistribution of PLZ4 was performed in a mouse xenograft model via tail vein injection and was confirmed with <it>ex vivo </it>imaging.</p> <p>Results</p> <p>PLZ4 exhibited high affinity and specific dose-dependent binding to canine bladder TCC cell lines, but not to normal canine urothelial cells. No significant changes in cell viability or proliferation were observed upon incubation with PLZ4. The <it>in vivo </it>and <it>ex vivo </it>optical imaging study showed that, when linked with the near-infrared fluorescent dye Cy5.5, PLZ4 substantially accumulated at the canine bladder cancer foci in the mouse xenograft model as compared to the control.</p> <p>Conclusions and Clinical Relevance</p> <p>PLZ4 can specifically bind to canine bladder cancer cells. This suggests that the preclinical studies of PLZ4 as a potential diagnostic and therapeutic agent can be performed in dogs with naturally occurring bladder cancer, and that PLZ4 can possibly be developed in the management of canine bladder cancer.</p

    Peptidases compartmentalized to the Ascaris suum intestinal lumen and apical intestinal membrane

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    The nematode intestine is a tissue of interest for developing new methods of therapy and control of parasitic nematodes. However, biological details of intestinal cell functions remain obscure, as do the proteins and molecular functions located on the apical intestinal membrane (AIM), and within the intestinal lumen (IL) of nematodes. Accordingly, methods were developed to gain a comprehensive identification of peptidases that function in the intestinal tract of adult female Ascaris suum. Peptidase activity was detected in multiple fractions of the A. suum intestine under pH conditions ranging from 5.0 to 8.0. Peptidase class inhibitors were used to characterize these activities. The fractions included whole lysates, membrane enriched fractions, and physiological- and 4 molar urea-perfusates of the intestinal lumen. Concanavalin A (ConA) was confirmed to bind to the AIM, and intestinal proteins affinity isolated on ConA-beads were compared to proteins from membrane and perfusate fractions by mass spectrometry. Twenty-nine predicted peptidases were identified including aspartic, cysteine, and serine peptidases, and an unexpectedly high number (16) of metallopeptidases. Many of these proteins co-localized to multiple fractions, providing independent support for localization to specific intestinal compartments, including the IL and AIM. This unique perfusion model produced the most comprehensive view of likely digestive peptidases that function in these intestinal compartments of A. suum, or any nematode. This model offers a means to directly determine functions of these proteins in the A. suum intestine and, more generally, deduce the wide array functions that exist in these cellular compartments of the nematode intestine
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