21 research outputs found

    Monitoring of wild pseudomonas biofilm strain conditions using statistical characterization of scanning electron microscopy images

    Get PDF
    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.The present paper proposes a novel method of quantification of the variation in biofilm architecture, in correlation with the alteration of growth conditions that include variations of the substrate and conditioning layer. The polymeric biomaterials serving as substrates are widely used in implants and indwelling medical devices, while the plasma proteins serve as the conditioning layer. The present method uses descriptive statistics of field emission scanning electron microscopy (FESEM) images of biofilms obtained during a variety of growth conditions. We aim to explore here the texture and fractal analysis techniques, to identify the most discriminatory features which are capable of predicting the difference in biofilm growth conditions. We initially extract some statistical features of biofilm images on bare polymer surfaces, followed by those on the same substrates adsorbed with two different types of plasma proteins, viz., bovine serum albumin (BSA) and fibronectin (FN), for two different adsorption times. The present analysis has the potential to act as a futuristic technology for developing a computerized monitoring system in hospitals with automated image analysis and feature extraction, which may be used to predict the growth profile of an emerging biofilm on surgical implants or similar medical applications.SDS acknowledges the funding from the Department of Science and Technology (DST), Govt. of India through the Women’s Scientist Scheme – A, project no. LS-466/WOS A/2012-2013

    Life Sciences Program Tasks and Bibliography

    Get PDF
    This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1995. Additionally, this inaugural edition of the Task Book includes information for FY 1994 programs. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web pag

    The second generation of the CCCM system for in-vitro cardiac tissue engineering.

    Get PDF
    Cardiovascular disease is the leading cause of death worldwide. When a myocardial infarction occurs, scar tissue compensates the damaged myocardial tissue. This scar tissue increases the stiffness of the heart tissue, reduces the heart’s function, and finally leads to the heart failure (HF) disease. To have the tissue engraftment, in-vitro cardiac tissue should have the same properties as the native mature cardiac tissue. However, current in-vitro cell culture technologies fail to accurately recreate the in-vivo like mechanically physiological environment for in-vitro cardiac tissue culture, and therefore, fail to regenerate the in-vivo like mature cardiac tissue. Hence, a microfluidic cardiac cell culture model (CCCM) system was developed to better recreate the cellular environment and advance cardiac regeneration. CCCM system replicates the hemodynamic loading and unloading conditions occurring inside the left ventricle of a heart. With this system, different pressures of human heart conditions may be replicated for a variety of clinical and physiologic conditions. For proof-of-concept, embryonic chick cardiac cells with normal heart condition were applied. Compared to the tissue cultured in a static condition, tissues stimulated in the CCCM system achieved an in-vivo like cardiac matured phenotype, had higher proliferating rate, showed more maturity, and expressed more contractile proteins. These results demonstrated that the CCCM system can be used to study the behavior of cardiomyocytes in different mechanical heart conditions and to create mature cardiac tissue which will benefit cardiac tissue transplant for HF

    Multiplexed microfabricated cell culture device for stem cell process development

    Get PDF
    In this thesis, a multiplexed micro-fabricated cell culture device is presented to probe the soluble micro-environment of stem cells. A large number of biological, physical and chemical variables determine the micro-environment of stem cells and affect therefore their fate. The soluble micro-environment is believed to play a pivotal role in controlling stem cell fate and its optimisation may therefore allow exploitation of applications such as regenerative medicine or drug discovery. However, novel tools are required to probe and optimise the soluble micro-environment. The ability to move small volumes of liquid and the minimal use of resources are important characteristics of microfluidic systems and thus, they are perfectly suited to study the micro-environment of stem cells. A microfluidic cell culture device must ful fil three important requirements to be of utility in stem cell bioprocess development. The first aspect addresses the need for adaptability and flexibility to implement changes in microfluidic designs to take account of the rapid progress in stem cell research. To this end, a packaging solution specifi cally designed for a microfluidic cell culture device has been developed. The packaging system has thus been complemented with a rapid fabrication method using a micro-milling machine to quickly fabricate disposable and easily reconfi gurable microfluidic chips. The packaging solution has a maximum burst pressure of approximately 7.5 bar and the fabrication method has a dimensional fidelity with less than 10% deviation from the nominal value. The second aspect focuses on the scalability and comparability of results and the feasibility of continuous culture of stem cells - both critical elements for the success of a microfluidic cell culture system for stem cell bioprocess development. A novel cell seeding method has been developed using a pipette to directly and carefully seed cells into a culture chamber within a microfluidic cell culture device. To prevent a wash-out of viable cells during continuous culture, a low hydrodynamic shear stress microfluidic chip has been developed. The cell culture device has been successfully tested using human embryonic stem cells (hESC) on feeder cells. The third aspect concerns the automated monitoring of stem cell bioprocesses in the cell culture device. A multiplexed micro fluidic bioreactor platform with time-lapse imaging has been developed to obtain data-rich experimental sets. The platform consisting of a cooled media reservoir and a pumping mechanism has been characterised and tested using mouse embryonic stem cells (mESC) as a proof of concept. The combination of these three aspects provides a basis towards a multiplexed microfabricated cell culture device, which allows data-rich experimentation and comparability with current benchscale culture vessels for stem cell expansion and di fferentiation

    DRUG TOXICITY TESTING ON CHIPS

    Get PDF
    Ph.DDOCTOR OF PHILOSOPH

    Medical Robotics

    Get PDF
    The first generation of surgical robots are already being installed in a number of operating rooms around the world. Robotics is being introduced to medicine because it allows for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, robots have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. The use of robotics in surgery will expand over the next decades without any doubt. Minimally Invasive Surgery (MIS) is a revolutionary approach in surgery. In MIS, the operation is performed with instruments and viewing equipment inserted into the body through small incisions created by the surgeon, in contrast to open surgery with large incisions. This minimizes surgical trauma and damage to healthy tissue, resulting in shorter patient recovery time. The aim of this book is to provide an overview of the state-of-art, to present new ideas, original results and practical experiences in this expanding area. Nevertheless, many chapters in the book concern advanced research on this growing area. The book provides critical analysis of clinical trials, assessment of the benefits and risks of the application of these technologies. This book is certainly a small sample of the research activity on Medical Robotics going on around the globe as you read it, but it surely covers a good deal of what has been done in the field recently, and as such it works as a valuable source for researchers interested in the involved subjects, whether they are currently “medical roboticists” or not

    Progenitor cells in auricular cartilage demonstrate promising cartilage regenerative potential in 3D hydrogel culture

    Get PDF
    The reconstruction of auricular deformities is a very challenging surgical procedure that could benefit from a tissue engineering approach. Nevertheless, a major obstacle is presented by the acquisition of sufficient amounts of autologous cells to create a cartilage construct the size of the human ear. Extensively expanded chondrocytes are unable to retain their phenotype, while bone marrow-derived mesenchymal stromal cells (MSC) show endochondral terminal differentiation by formation of a calcified matrix. The identification of tissue-specific progenitor cells in auricular cartilage, which can be expanded to high numbers without loss of cartilage phenotype, has great prospects for cartilage regeneration of larger constructs. This study investigates the largely unexplored potential of auricular progenitor cells for cartilage tissue engineering in 3D hydrogels

    Calcium signaling modulators: a novel pharmacological intervention to delay aging in Caenorhabditis elegans

    Get PDF
    Ca2+ is a second messenger that affects nearly every aspect or cellular life including muscle contraction, neuronal secretion and cell proliferation and differentiation. The dysregulation of the cellular toolkit that controls and maintains Ca2+ homeostasis has been linked to the physiopathology of the aging process including neurodegeneration. Caenorhabditis elegans has been proven to be an excellent model organism to study aging and neurodegeneration due to the conservation of numerous signaling pathways that have been proven to modulate aging, and the availability of several models of neurodegenerative diseases. Moreover, the interrelationship between aging and Ca2+ signaling can be studied in the worms because of their transparent cuticle that allows to perform in vivo Ca2+ dynamics studies throughout the whole life of the organisms. The metabolic pathways that are known to regulate aging in C. elegans are the so called nutrient sensing pathways. All these pathways, that are conserved in mammals, are able to respond to changes in nutrient availability that, in the end, affect the longevity of the worms. These pathways are the insulin/insulin-likegrowth factor (IGF-1) signaling pathway (IIS), the mechanistic target of rapamycin (mTOR) signaling pathway, the adenosine monophosphate-activated protein kinase (AMPK) pathway, and the sirtuins pathway. Although not much information about how intracellular Ca2+ regulates these pathways, there is some evidence that suggests that Ca2+ might be implicated in the modulation of nutrient sensing pathways activities. This thesis has focused in the study of the interrelationship between Ca2+ signaling and nutrient sensing pathways, and its possible effects in the aging process through two different pharmacological approaches: the submaximal inhibition of sarco-endoplasmic reticulum calcium-ATPase (SERCA) using 2,5-BHQ and thapsigargin, and the submaximal inhibition of the mitochondrial Na+/Ca2+ exchanger using CGP37157. SERCA refills the endoplasmic reticulum (ER) with Ca2+ up to the millimolar range being the main controller of the ER [Ca2+] level, implicated in the modulation of cytosolic Ca2+ signaling and ER-mitochondria Ca2+ transfer. In this work it has been proven that the submaximal inhibition of SERCA with 2,5-BHQ and thapsigargin induced an increase in the lifespan of C. elegans worms and that this effect was mediated by the modulation of mTOR and AMPK signaling pathways. Moreover, it was also discarded that the effect was mediated by the activation of the ER stress response. CGP37157 is a benzothiazepine with neuroprotective effects in several in vitro models of excitotoxicity involving dysregulation of intracellular Ca2+ homeostasis. CGP37157 has been used for decades as an inhibitor of the mitochondrial Na+/Ca2+ 20 exchanger (mNCX), although several off targets have been described. Throughout this thesis, the effects of CGP37157 in C. elegans healthspan, as well as its possible modulation of nutrient sensing pathways and Ca2+ dynamics, have been explored. Our results show that the treatment with CGP37157 is able to induce an increase in C. elegans life expectancy through the modulation of the mTOR and IIS signaling pathways. Moreover, it was proven that a functional electron transport chain activity was required for CGP37157 to exert its effects, and that CGP37157 treatment induced changes in intracellular Ca2+, including cytosolic and mitochondrial Ca2+ dynamics changes in two different muscular systems, the pharynx and the vulva. Finally, the changes induced by CGP37157 also caused an improvement in worm’s locomotion and muscle function delaying the sarcopenia process and improving mitochondrial integrity and organization in C. elegans body wall muscle cells. In conclusion, this work has described two novel pharmacological interventions that improve C. elegans lifespan through the modulation of Ca2+ signaling in a different manner. These results outline the possible therapeutic effects of both SERCA inhibitors and CGP37157 in the aging process, and the importance of Ca2+ signaling in the regulation and evolution of aging related physiopathology.Departamento de Bioquímica y Biología Molecular y FisiologíaDoctorado en Investigación Biomédic
    corecore