33 research outputs found

    Nanoencapsulated capsaicin changes migration behavior and morphology of madin darby canine kidney cell monolayers

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    We have developed a drug delivery nanosystem based on chitosan and capsaicin. Both substances have a wide range of biological activities. We investigated the nanosystem’s influence on migration and morphology of Madin Darby canine kidney (MDCK-C7) epithelial cells in comparison to the capsaicin-free nanoformulation, free capsaicin, and control cells. For minimally-invasive quantification of cell migration, we applied label-free digital holographic microscopy (DHM) and single-cell tracking. Moreover, quantitative DHM phase images were used as novel stain-free assay to quantify the temporal course of global cellular morphology changes in confluent cell layers. Cytoskeleton alterations and tight junction protein redistributions were complementary analyzed by fluorescence microscopy. Calcium influx measurements were conducted to characterize the influence of the nanoformulations and capsaicin on ion channel activities. We found that both, capsaicin-loaded and unloaded chitosan nanocapsules, and also free capsaicin, have a significant impact on directed cell migration and cellular motility. Increase of velocity and directionality of cell migration correlates with changes in the cell layer surface roughness, tight junction integrity and cytoskeleton alterations. Calcium influx into cells occurred only after nanoformulation treatment but not upon addition of free capsaicin. Our results pave the way for further studies on the biological significance of these findings and potential biomedical applications, e.g. as drug and gene carriers

    Causes of genome instability: the effect of low dose chemical exposures in modern society.

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    Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus, genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss. This review raises the hypothesis that in addition to known human carcinogens, exposure to low dose of other chemicals present in our modern society could contribute to carcinogenesis by indirectly affecting genome stability. The selected chemicals with their mechanisms of action proposed to indirectly contribute to genome instability are: heavy metals (DNA repair, epigenetic modification, DNA damage signaling, telomere length), acrylamide (DNA repair, chromosome segregation), bisphenol A (epigenetic modification, DNA damage signaling, mitochondrial function, chromosome segregation), benomyl (chromosome segregation), quinones (epigenetic modification) and nano-sized particles (epigenetic pathways, mitochondrial function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make scientists aware of the increasing need to unravel the underlying mechanisms via which chemicals at low doses can induce genome instability and thus promote carcinogenesis

    The ALDY Load Distribution System

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    This report describes ALDY (Adaptive Load Distribution SYstem). ALDY is a combination of system integrated and application integrated load distribution. It can be used either directly by a parallel program or by the runtime system of a parallel programming environment. The flexible object model and system independent load distribution strategies ensure that ALDY is portable over a large range of programming environments and a large range of hardware platforms. In addition to the conventional task farming paradigm used by most load distribution systems (for example, Dynamo [T ar94], and Mentat [Gri93]), ALDY supports the migration of application objects. Another ALDY feature is the realization of adaptive load distribution: Methods for adaptive load distribution are robust with respect to varying availability of system resources due to heterogeneity or processes which are generated by other users. Section 2 surveys the functions and design objectives of ALDY and describes the ALDY load distribution model. Section 3 presents the ALDY library interface. The basic concepts of the ALDY load distribution strategies are explained in section 4. In section 5, three application examples, each representing a large class of similar applications are described. Section 6 gives a summary and an outlook to our future work. 2 Concept

    Integration of Load Distribution into ParMod-C

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    The major part of environments for parallel programming in distributed systems either neglects load distribution support or realizes load distribution by the trivial task farming paradigm. This paper presents new language concepts for the support of application integrated load distribution. In addition to the task farming approach, the system can also dynamically migrate objects. Active objects and passive objects are combined to a very flexible and elegant programming model. Specific tasks for initialization and migration are used to realize efficient and portable load distribution mechanisms. The paper describes the new programming model and presents language constructs realizing this model. The language constructs are an extension of the parallel and distributed programming language ParMod-C. A program example shows the usage of the new language constructs and demonstrates easy implementation of load distribution using the new concept. 1 Introduction Environments for parallel progr..

    Supporting Application Integrated Load Distribution for Message Passing Programs

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    This paper emphasizes an aspect which is often neglected by programming environments but which is essential for an efficient execution: the support of load distribution

    Using Agents for Parallel Programming in Workstation Networks

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    This paper describes a new portable load distribution library, called ALDY (Adaptive Load Distribution System) [2]. The idea of ALDY is to use an agent based programming model. It combines dynamic assignment of tasks and migration of agents among processes. 2 Programming Mode
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