The International Journal of Medical Students, a Platform for Medical Student Research Worldwide

N/

Peritoneal repairing cells: A type of bone marrow derived progenitor cells involved in mesothelial regeneration

The peritoneal mesothelium exhibits a high regenerative ability. Peritoneal regeneration is concomitant with the appearance, in the coelomic cavity, of a free-floating population of cells whose origin and functions are still under discussion. We have isolated and characterized this cell population and we have studied the process of mesothelial regeneration through flow cytometry and confocal microscopy in a murine model lethally irradiated and reconstituted with GFP-expressing bone marrow cells. In unoperated control mice, most free cells positive for mesothelin, a mesothelial marker, are green fluorescent protein (GFP). However, 24 hrs after peritoneal damage, free mesothelin+/ GFP+ cells appear in peritoneal lavages. Cultured lavage peritoneal cells show colocalization of GFP with mesothelial (mesothelin, cytokeratin) and fibroblastic markers. Immunohistochemical staining of the peritoneal wall also revealed colocalization of GFP with mesothelial markers and with procollagen-1 and smooth muscle α-actin. This was observed in the injured area as well as in the surrounding not-injured peritoneal surfaces. These cells, which we herein call peritoneal repairing cells (PRC), are very abundant 1 week after surgery covering both the damaged peritoneal wall and the surrounding uninjured area. However, they become very scarce 1 month later, when the mesothelium has completely healed. We suggest that PRC constitute a type of monocyte-derived cells, closely related with the tissue-repairing cells known as 'fibrocytes' and specifically involved in peritoneal reparation. Thus, our results constitute a synthesis of the different scenarios hitherto proposed about peritoneal regeneration, particularly recruitment of circulating progenitor cells and adhesion of free-floating coelomic cells. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.(Ministerio de Ciencia e Innovación), RD06/0010/0015 (TerCel network, ISCIII), P06-CTS-01614, P08-CTS-03618 (Junta de AndalucÌa) and LSHM-CT-2005–018630 (VI framework, UE)Peer Reviewe

Towards a best practice for the use of active non-contact surface scanning to record human skeletal remains from archaeological contexts

Active surface scanners emit light or a laser stripe to record the exterior surface of an object or landscape, providing results in three dimensions. The use of active surface scanners to record anthropological and archaeological contexts has increased within the last few years, creating a number of sub-contexts within these disciplines, and allowing a further development of certain applications, such as quantitative analysis, the use of replicas in education and museums, and the creation of digital databases archived in institutions. However with guidance, this paper aims to assess the advantages and disadvantages of active surface scanning and the potential for research with regards to the recording and analysis of human skeletal remains. The key advantages and uses identified include: quantitative digitisation, geometric morphometric studies, conservation, preservation, documentation, and reconstruction. However, surface scanning also has some limitations, including: cost, technological expertise, the need for a power source, computing requirements, and data size. Overall, the application of active surface scanning technology to archaeological skeletal remains will provide a vital digital archive that will serve to preserve the integrity of this fragile and finite resource for future generations. This is particularly important within the current developer-funded environment in which many skeletal collections, including those yielding unique or unusual pathological or morphological features, are re-buried, with only very limited time for analysis

Circulating exosomes deliver free fatty acids from the bloodstream to cardiac cells:Possible role of CD36

Regulation of circulating free fatty acid (FFA) levels and delivery is crucial to maintain tissue homeostasis. Exosomes are nanomembranous vesicles that are released from diverse cell types and mediate intercellular communication by delivering bioactive molecules. Here, we sought to investigate the uptake of FFAs by circulating exosomes, the delivery of FFA-loaded exosomes to cardiac cells and the possible role of the FFA transporter CD36 in these processes. Circulating exosomes were purified from the serum of healthy donors after an overnight fast (F) or 20 minutes after a high caloric breakfast (postprandial, PP). Western blotting, Immunogold Electron Microscopy and FACS analysis of circulating exosomes showed that CD36 was expressed under both states, but was higher in postprandial-derived exosomes. Flow cytometry analysis showed that circulating exosomes were able to take-up FFA directly from serum. Importantly, preincubation of exosomes with a blocking CD36 antibody significantly impeded uptake of the FFA analogue BODIPY, pointing to the role of CD36 in FFA exosomal uptake. Finally, we found that circulating exosomes could delivery FFA analogue BODIPY into cardiac cells ex vivo and in vivo in a mice model. Overall, our results suggest a novel mechanism in which circulating exosomes can delivery FFAs from the bloodstream to cardiac tissue. Further studies will be necessary to understand this mechanism and, in particular, its potential involvement in metabolic pathologies such as obesity, diabetes and atherosclerosis

Efficient Small Extracellular Vesicles (EV) Isolation Method and Evaluation of EV-Associated DNA Role in Cell-Cell Communication in Cancer

SIMPLE SUMMARY: Small extracellular vesicles (sEVs) released by all cell types function as a mediator in intercellular communication that can promote cell division and survival to remodel the tumor microenvironment to develop tumor invasion and metastasis. Even though dsDNA baggage is associated with all small EV populations, the functional role of EV-DNA in cancer remains poorly understood. This is due to a lack of methods allowing the efficient separation of small EVs (sEVs) from other non-sEV components. The main aim of our study was to develop an efficient sEV isolation method along with EV-associated DNA (EV-DNA) monitoring tool to evaluate the role of EV-DNA as a mediator of cell–cell communication in cancer. Our detailed small EV-DNA characterization confirmed that isolated sEVs using the TSU method (Tangential flow filtration + Size exclusion chromatography + Ultrafiltration) are free from contaminants such as cell-free and apoptotic bodies DNA, making TSU ideal for performing EV-DNA functional studies. Next, we revealed the exact EV-DNA distribution in the recipient cells using 3D image analysis and the association of EV-DNA with key cellular proteins, which may have an essential role in cancer. In the leukemia model, EV-DNA isolated from leukemia cell lines associated with mesenchymal stromal cells (MSCs), a crucial factor in the bone marrow (BM) microenvironment. ABSTRACT: Small extracellular vesicles (sEVs) play essential roles in intercellular signaling both in normal and pathophysiological conditions. Comprehensive studies of dsDNA associated with sEVs are hampered by a lack of methods, allowing efficient separation of sEVs from free-circulating DNA and apoptotic bodies. In this work, using controlled culture conditions, we enriched the reproducible separation of sEVs from free-circulated components by combining tangential flow filtration, size-exclusion chromatography, and ultrafiltration (TSU). EV-enriched fractions (F2 and F3) obtained using TSU also contained more dsDNA derived from the host genome and mitochondria, predominantly localized inside the vesicles. Three-dimensional reconstruction of high-resolution imaging showed that the recipient cell membrane barrier restricts a portion of EV-DNA. Simultaneously, the remaining EV-DNA overcomes it and enters the cytoplasm and nucleus. In the cytoplasm, EV-DNA associates with dsDNA-inflammatory sensors (cGAS/STING) and endosomal proteins (Rab5/Rab7). Relevant to cancer, we found that EV-DNA isolated from leukemia cell lines communicates with mesenchymal stromal cells (MSCs), a critical component in the BM microenvironment. Furthermore, we illustrated the arrangement of sEVs and EV-DNA at a single vesicle level using super-resolution microscopy. Altogether, employing TSU isolation, we demonstrated EV-DNA distribution and a tool to evaluate the exact EV-DNA role of cell–cell communication in cancer

Efficient Non-viral Gene Delivery into Human Hematopoietic Stem Cells by Minicircle Sleeping Beauty Transposon Vectors

The Sleeping Beauty (SB) transposon system is a non-viral gene delivery platform that combines simplicity, inexpensive manufacture, and favorable safety features in the context of human applications. However, efficient correction of hematopoietic stem and progenitor cells (HSPCs) with non-viral vector systems, including SB, demands further refinement of gene delivery techniques. We set out to improve SB gene transfer into hard-to-transfect human CD34 + cells by vectorizing the SB system components in the form of minicircles that are devoid of plasmid backbone sequences and are, therefore, significantly reduced in size. As compared to conventional plasmids, delivery of the SB transposon system as minicircle DNA is 3c20 times more efficient, and it is associated with up to a 50% reduction in cellular toxicity in human CD34 + cells. Moreover, providing the SB transposase in the form of synthetic mRNA enabled us to further increase the efficacy and biosafety of stable gene delivery into hematopoietic progenitors ex vivo. Genome-wide insertion site profiling revealed a close-to-random distribution of SB transposon integrants, which is characteristically different from gammaretroviral and lentiviral integrations in HSPCs. Transplantation of gene-marked CD34 + cells in immunodeficient mice resulted in long-term engraftment and hematopoietic reconstitution, which was most efficient when the SB transposase was supplied as mRNA and nucleofected cells were maintained for 4\u20138 days in culture before transplantation. Collectively, implementation of minicircle and mRNA technologies allowed us to further refine the SB transposon system in the context of HSPC gene delivery to ultimately meet clinical demands of an efficient and safe non-viral gene therapy protocol. Ivics and collegues refined the Sleeping Beauty transposon system for gene transfer in human hematopoietic stem and progenitor cells by vectorizing the transposon components as minicircle DNA and synthetic mRNA. The advanced vector system enables efficient and safe non-viral engineering of hematopoietic cells that can be transplanted into immunodeficient mice

Análisis del perfil motivacional de estudiantes universitarios de tercer semestre del programa de psicología

Resulta de gran importancia la aplicación de instrumentos para medir el nivel motivacional de una población, ya que, al obtener ciertos datos permite determinar la forma adecuada de interactuar con los mismos. El análisis del perfil motivacional aporta información relevante para el desempeño académico de los estudiantes universitarios. Para lograr dicho propósito se empleó un instrumento que evalúa el perfil motivacional tomando como referencia el modelo de rueda de motivos que expone Valderrama (2010), el cual, evalúa diversos motivos que pueden influir en el rendimiento académico y en otras conductas laborales. Dicho instrumento cuenta con una escala de respuesta de tipo likert con 6 opciones, desde 1 (nada importante para mi) a 6 (extremadamente importante para mi) . En lo que corresponde al procesamiento de la información, se utilizó la plataforma formularios de google; Con esto se obtuvieron los datos más importantes desde el análisis estadísticoIt is of great importance to use instruments to measure the motivational level of a population, since, by obtaining certain data, it allows you to determine the appropriate way to interact with them. The analysis of the motivational profile provides relevant information for the academic performance of university students. To achieve this purpose, an instrument was used that evaluates the motivational profile based on the motif wheel model presented by Valderrama (2010) which evaluates various motives that can influence performance and other work behaviors. This instrument has a likert response scale with 6 options, from 1 being (nothing important to me) to 6 being (extremely important to me). As for the processing of information, the google forms platform was used; with this, the most important data from the statistical analysis were obtained

Feeding programmes based on highly-digestible fibre weaning diets: effects on health, growth performance and carcass and meat quality in rabbits

The effect of three different dietary programmes on health, growth performance and carcass and meat quality in young rabbits weaned at 28 d was studied using a diet (F) rich in highly-digestible fibre, from 17 to 63 d of age (group FF); using diet F from 17 to 42 d followed by a diet poor in highly-digestible fibre and rich in starch and fat (S) until 63 d (group FS); and using a standard diet C with intermediate highly-digestible fibre and starch content, containing 100 ppm of zinc-bacitracin, from 17 to 63 d (group CC). A highly-digestible fibre diet could be useful to reduce the incidence of digestive disorders. However, it decreased slaughter weight (2294 g in FF vs. 2406 g in CC; P<0.05) and carcass and meat traits, e.g. dressing out percentage (55.4% in FF vs. 56.7% in CC; P<0.05), meat to bone ratio (5.73 in FF vs. 5.94 in CC; P<0.05) and hind leg fat content (3.81% in FF vs. 4.71% in CC; P<0.05) at 63 d of age. Switching to a high starch and fat diet at late fattening improved chilled carcass weight at 63 d of age (1339 g in FS vs. 1263 g in FF; P<0.05) mainly through the promotion of liver development (7.53% in group FS vs. 6.47% in group FF; P<0.05) and fat deposition (3.89% in FS vs. 2.63% in FF; P<0.05), and increased hind leg fat content (+1.2 points of fat percentage; P<0.05). However, this switch increased health risk (35.1% in FS vs. 17.6% in FF; P<0.05).This study was supported by the Interministerial Commission for Science and Technology (CICYT) from the Spanish Government Grant number AGL2011-30170-C02-01 is gratefully acknowledged. Funding from the Spanish Ministry of Economy and Competitiveness for Madam Pascual's contract (PTA2011-5888-T) is also gratefully acknowledged.Pascual Amorós, MDLD.; Soler Sanchis, MD.; Cervera Fras, MC.; Pla Torres, M.; Pascual Amorós, JJ.; Blas Ferrer, E. (2014). Feeding programmes based on highly-digestible fibre weaning diets: effects on health, growth performance and carcass and meat quality in rabbits. Livestock Science. 169:88-95. https://doi.org/10.1016/j.livsci.2014.07.007S889516

Contrast-enhanced ultrasound of the spleen: an introduction and pictorial essay

A wide variety of pathologies can produce focal lesions within the spleen. These are being more frequently encountered as imaging technology improves. It is vital that radiologists are aware of these pathologies to enable accurate diagnosis. The role of ultrasound contrast in splenic disease will be discussed and illustrated with cases likely to be encountered by general and abdominal radiologists