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Find video protocols related to scientific articles indexed in Pubmed.
The immunophenotype of mast cells and its utility in the diagnostic work-up of systemic mastocytosis.
J. Leukoc. Biol.
PUBLISHED: 11-07-2014
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SM comprises a heterogeneous group of disorders, characterized by an abnormal accumulation of clonal MCs in 1 or more tissues, frequently involving the skin and BM. Despite the fact that most adult patients (>90%) carry the same genetic lesion (D816V KIT mutation), the disease presents with multiple variants with very distinct clinical and biologic features, a diverse prognosis, and different therapeutic requirements. Recent advances in the standardization of the study of BM MC by MFC allowed reproducible identification and characterization of normal/reactive MCs and their precursors, as well as the establishment of the normal MC maturational profiles. Analysis of large groups of patients versus normal/reactive samples has highlighted the existence of aberrant MC phenotypes in SM, which are essential for the diagnosis of the disease. In turn, 3 clearly distinct and altered maturation-associated immunophenotypic profiles have been reported recently in SM, which provide criteria for the distinction between ISM patients with MC-restricted and multilineage KIT mutation; thus, immunphenotyping also contributes to prognostic stratification of ISM, particularly when analysis of the KIT mutation on highly purified BM cells is not routinely available in the diagnostic work-up of the disease.
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FISH analysis of PTEN in endometrial carcinoma. Comparison with SNP arrays and MLPA.
Histopathology
PUBLISHED: 10-30-2014
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To check the usefulness of a standardized protocol of PTEN FISH in 31 endometrial carcinomas (ECs) in comparison with SNP array (SNPA), multiplex ligation-dependent probe amplification (MLPA), and immunohistochemistry.
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Failure to find symmetry in pigeons after multiple exemplar training.
Psicothema
PUBLISHED: 10-24-2014
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An experiment with pigeons was conducted for 46 months in order to test the multiple-exemplar training (MET) hypothesis of symmetry derivation. According to this hypothesis, symmetry is progressively derived after an extensive training of multiple examples of direct and inverse relations among arbitrary stimuli.
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Drug delivery: nanoengineered particles for enhanced intra-articular retention and delivery of proteins (adv. Healthcare mater. 10/2014).
Adv Healthc Mater
PUBLISHED: 10-11-2014
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Localized intra-articular delivery of anti-inflammatory proteins can reduce inflammation in osteoarthritis but poses a challenge because of rapid clearance within few hours of injection. On page 1562, A. J. García and co-workers report a new class of polymer that forms self-assembled nanoparticles with therapeutic proteins for prolonged retention in intra-articular joint spaces compared to bolus protein doses.
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P2Y2 purinergic receptor activation is essential for efficient hepatocyte proliferation in response to partial hepatectomy.
Am. J. Physiol. Gastrointest. Liver Physiol.
PUBLISHED: 10-11-2014
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Extracellular nucleotides, via activation of P2 purinergic receptors, influence hepatocyte proliferation and liver regeneration in response to 70% partial hepatectomy (PH). Adult hepatocytes express multiple P2Y (G-protein coupled) and P2X (ligand-gated ion channels) purinergic receptor subtypes. However, the identity of key receptor subtype(s) important for efficient hepatocyte proliferation in regenerating livers remains unknown. In order to evaluate the impact of P2Y2 purinergic receptor-mediated signaling on hepatocyte proliferation in regenerating livers, wild type (WT) and P2Y2 purinergic receptor knockout (P2Y2-/-) mice were subjected to 70% PH. Liver tissues were analyzed for activation of early events critical for hepatocyte priming and subsequent cell cycle progression. Our findings suggest that early activation of p42/44 ERK MAPK (5 min), early growth response-1 (Egr-1), and activator protein-1 (AP-1) DNA-binding activity (30 min) as well as subsequent hepatocyte proliferation (24-72 hr) in response to 70% PH were impaired in P2Y2-/- mice. Interestingly, early induction of cytokines (TNF?, IL-6) and cytokine-mediated signaling (NF-kB, STAT-3) were intact in P2Y2-/- remnant livers, uncovering the importance of cytokine-independent and nucleotide-dependent early priming events critical for subsequent hepatocyte proliferation in regenerating livers. Hepatocytes isolated from WT and P2Y2-/- livers were treated with ATP for 5-120 min and 12-24 hr. Extracellular ATP alone, via activation of P2Y2 purinergic receptors, was sufficient to induce ERK phosphorylation, Egr-1 protein expression, and key cyclins and cell cycle progression of hepatocytes in vitro. Collectively, these findings highlight the functional significance of P2Y2 purinergic receptor activation for efficient hepatocyte priming and proliferation in response to PH.
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[Epiploic appendagitis: a rare cause of abdominal pain].
Cir Cir
PUBLISHED: 08-29-2014
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Epiploic appendagitis is an atypical cause of abdominal pain whose knowledge could avoid diagnostic or treatment errors. Diagnosis has been performed with abdominal ultrasound or tomography with the only treatment being nonsteroidal anti-inflammatory drugs.
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The effect of conditional inactivation of beta 1 integrins using twist 2 Cre, Osterix Cre and osteocalcin Cre lines on skeletal phenotype.
Bone
PUBLISHED: 08-27-2014
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Skeletal development and growth are complex processes regulated by multiple microenvironmental cues, including integrin-ECM interactions. The ?1 sub-family of integrins is the largest integrin sub-family and constitutes the main integrin binding partners of collagen I, the major ECM component of bone. As complete ?1 integrin knockout results in embryonic lethality, studies of ?1 integrin function in vivo rely on tissue-specific gene deletions. While multiple in vitro studies indicate that ?1 integrins are crucial regulators of osteogenesis and mineralization, in vivo osteoblast-specific perturbations of ?1 integrins have resulted in mild and sometimes contradictory skeletal phenotypes. To further investigate the role of ?1 integrins on skeletal phenotype, we used the Twist2-Cre, Osterix-Cre and osteocalcin-Cre lines to generate conditional ?1 integrin deletions, where Cre is expressed primarily in mesenchymal condensation, pre-osteoblast, and mature osteoblast lineage cells respectively within these lines. Mice with Twist2-specific ?1 integrin disruption were smaller, had impaired skeletal development, especially in the craniofacial and vertebral tissues at E19.5, and did not survive beyond birth. Osterix-specific ?1 integrin deficiency resulted in viable mice which were normal at birth but displayed early defects in calvarial ossification, incisor eruption and growth as well as femoral bone mineral density, structure, and mechanical properties. Although these defects persisted into adulthood, they became milder with age. Finally, a lack of ?1 integrins in mature osteoblasts and osteocytes resulted in minor alterations to femur structure but had no effect on mineral density, biomechanics or fracture healing. Taken together, our data indicate that ?1 integrin expression in early mesenchymal condensations play an important role in skeletal ossification, while ?1 integrin-ECM interactions in pre-osteoblast, odontoblast- and hypertrophic chondryocyte-lineage cells regulate incisor eruption and perinatal bone formation in both intramembranously and endochondrally formed bones in young, rapidly growing mice. In contrast, the osteocalcin-specific ?1 integrin deletion had only minor effects on skeletal phenotype.
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Theory and data for simulating fine-scale human movement in an urban environment.
J R Soc Interface
PUBLISHED: 08-22-2014
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Individual-based models of infectious disease transmission depend on accurate quantification of fine-scale patterns of human movement. Existing models of movement either pertain to overly coarse scales, simulate some aspects of movement but not others, or were designed specifically for populations in developed countries. Here, we propose a generalizable framework for simulating the locations that an individual visits, time allocation across those locations, and population-level variation therein. As a case study, we fit alternative models for each of five aspects of movement (number, distance from home and types of locations visited; frequency and duration of visits) to interview data from 157 residents of the city of Iquitos, Peru. Comparison of alternative models showed that location type and distance from home were significant determinants of the locations that individuals visited and how much time they spent there. We also found that for most locations, residents of two neighbourhoods displayed indistinguishable preferences for visiting locations at various distances, despite differing distributions of locations around those neighbourhoods. Finally, simulated patterns of time allocation matched the interview data in a number of ways, suggesting that our framework constitutes a sound basis for simulating fine-scale movement and for investigating factors that influence it.
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Different gDNA content in the subpopulations of prostate cancer extracellular vesicles: apoptotic bodies, microvesicles, and exosomes.
Prostate
PUBLISHED: 08-11-2014
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Extracellular vesicles (EVs) are cell-derived membrane vesicles. EVs contain several RNAs such as mRNA, microRNAs, and ncRNAs, but less is known of their genomic DNA (gDNA) content. It is also unknown whether the DNA cargo is randomly sorted or if it is systematically packed into specific EV subpopulations. The aim of this study was to analyze whether different prostate cancer (PCa) cell-derived EV subpopulations (apoptotic bodies, microvesicles, and exosomes) carry different gDNA fragments.
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A genome-wide association study identifies a novel locus at 6q22.1 associated with ulcerative colitis.
Hum. Mol. Genet.
PUBLISHED: 07-31-2014
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The genetic analysis of ulcerative colitis (UC) has provided new insights into the etiology of this prevalent inflammatory bowel disease. However, most of the heritability of UC (>70%) has still not been characterized. To identify new risk loci for UC we have performed the first genome-wide association study (GWAS) in a Southern European population and undertaken a meta-analysis study combining the newly genotyped 825 UC patients and 1525 healthy controls from Spain with the six previously published GWAS comprising 6687 cases and 19 718 controls from Northern-European ancestry. We identified a novel locus with genome-wide significance at 6q22.1 [rs2858829, P = 8.97 × 10(-9), odds ratio (OR) (95% confidence interval, CI] = 1.12 (1.08-1.16)] that was validated with genotype data from a replication cohort of the same Southern European ancestry consisting in 1073 cases and 1279 controls [combined P = 7.59 × 10(-10), OR (95% CI) = 1.12 (1.08-1.16)]. Furthermore, we confirmed the association of 33 reported associations with UC and we nominally validated the GWAS results of nine new risk loci (P < 0.05, same direction of effect). SNP rs2858829 lies in an intergenic region and is a strong cis-eQTL for FAM26F gene, a gene that is shown to be selectively upregulated in UC colonic mucosa with active inflammation. Our results provide new insight into the genetic risk background of UC, confirming that there is a genetic risk component that differentiates from Crohn's Disease, the other major form of inflammatory bowel disease.
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The influence of the parents' educational level and participants' age in the derivation of equivalence-equivalence.
Psicothema
PUBLISHED: 07-30-2014
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The objective of this work was the study of analogical reasoning from the perspective of the equivalence-equivalence phenomenon.
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Vinculin-dependent actin bundling regulates cell migration and traction forces.
Biochem. J.
PUBLISHED: 07-10-2014
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Vinculin binding to actin filaments is thought to be critical for force transduction within a cell, but direct experimental evidence to support this conclusion has been limited. In this study,we found mutation (R1049E) of the vinculin tail impairs its ability to bind F-actin, stimulate actin polymerization, and bundle F-actin in vitro. Further, mutant (R1049E) vinculin expressing cells are altered in cell migration, which is accompanied by changes in cell adhesion, cell spreading, and cell generation of traction forces, providing direct evidence for the critical role of vinculin in mechanotransduction at adhesion sites. Lastly, we herein discuss the viability of models detailing the F-actin-binding surface on vinculin in context of our mutational analysis.
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Karyotype versus genomic hybridization for the prenatal diagnosis of chromosomal abnormalities: A meta-analysis.
Am. J. Obstet. Gynecol.
PUBLISHED: 07-09-2014
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The aim of this study was to determine the diagnostic accuracy of comparative genomic hybridization (CGH) compared with karyotyping for the detection of numerical and structural chromosomal alterations in prenatal diagnosis.
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Solid-phase library synthesis of bi-functional derivatives of oleanolic and maslinic acids and their cytotoxicity on three cancer cell lines.
ACS Comb Sci
PUBLISHED: 06-18-2014
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A wide set of 264 compounds has been semisynthesized with high yields and purities. These compounds have been obtained through easy synthetic processes based on a solid-phase combinatorial methodology. All the members of this library have one central core of a natural pentacyclic triterpene (oleanolic or maslinic acid) and differ by 6 amino acids, coupled with the carboxyl group at C-28 of the triterpenoid skeleton, and by 10 different acyl groups attached to the hydroxyl groups of the A-ring of these molecules. According to the literature on the outstanding and promising pharmacological activities of other similar terpene derivatives, some of these compounds have been tested for their cytotoxic effects on the proliferation of three cancer cell lines: B16-F10, HT29, and Hep G2. In general, we have found that around 70% of the compounds tested show cytotoxicity in all three of the cell lines selected; around 60% of the cytotoxic compounds are more effective than their corresponding precursors, that is, oleanolic (OA) or maslinic (MA) acids; and nearly 50% of the cytotoxic derivatives have IC50 values between 2- to 320-fold lower than their corresponding precursor (OA or MA).
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The neural crest is a source of mesenchymal stem cells with specialized hematopoietic stem cell niche function.
Elife
PUBLISHED: 06-16-2014
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Mesenchymal stem cells (MSCs) and osteolineage cells contribute to the hematopoietic stem cell (HSC) niche in the bone marrow of long bones. However, their developmental relationships remain unclear. In this study, we demonstrate that different MSC populations in the developing marrow of long bones have distinct functions. Proliferative mesoderm-derived nestin(-) MSCs participate in fetal skeletogenesis and lose MSC activity soon after birth. In contrast, quiescent neural crest-derived nestin(+) cells preserve MSC activity, but do not generate fetal chondrocytes. Instead, they differentiate into HSC niche-forming MSCs, helping to establish the HSC niche by secreting Cxcl12. Perineural migration of these cells to the bone marrow requires the ErbB3 receptor. The neonatal Nestin-GFP(+) Pdgfr?(-) cell population also contains Schwann cell precursors, but does not comprise mature Schwann cells. Thus, in the developing bone marrow HSC niche-forming MSCs share a common origin with sympathetic peripheral neurons and glial cells, and ontogenically distinct MSCs have non-overlapping functions in endochondrogenesis and HSC niche formation.
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When a clear strong voice was needed: A retrospective review of Watson's (1924/1930) behaviorism.
J Exp Anal Behav
PUBLISHED: 06-16-2014
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Despite the attention given John B. Watson during the century since he introduced behaviorism, there remain questions about what he really contributed. He is still appropriately criticized for his arrogant self-promotion and especially for his perceived emphasis on a simple S-R reflexology. However, we argue that the former was necessary at the time and that criticism of Watson on the second count only diverts attention from the genuine contributions that he did make. In support of these contentions we examine several aspects of his contributions that warrant clarification, namely, his promotion of applied comparative psychology, his views on the nature of mind, his originality, criticism from and respect afforded by contemporaries, his relation to recent interest in "the embodiment of mind," his treatment of thinking, and his appreciation of Freud's work. We organize our discussion around specific chapters of the two editions of Behaviorism, but in support of our arguments we include publications of Watson that are less well known. Those works develop some important points that are only briefly treated in both editions of Behaviorism.
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Complications in the management of bladder trauma in a third level hospital.
Arch. Esp. Urol.
PUBLISHED: 06-04-2014
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To determine the frecuency of complications during the management of bladder trauma and its associated factors in a third level reference Hospital.
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Optimal sampling strategies for detecting zoonotic disease epidemics.
PLoS Comput. Biol.
PUBLISHED: 06-01-2014
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The early detection of disease epidemics reduces the chance of successful introductions into new locales, minimizes the number of infections, and reduces the financial impact. We develop a framework to determine the optimal sampling strategy for disease detection in zoonotic host-vector epidemiological systems when a disease goes from below detectable levels to an epidemic. We find that if the time of disease introduction is known then the optimal sampling strategy can switch abruptly between sampling only from the vector population to sampling only from the host population. We also construct time-independent optimal sampling strategies when conducting periodic sampling that can involve sampling both the host and the vector populations simultaneously. Both time-dependent and -independent solutions can be useful for sampling design, depending on whether the time of introduction of the disease is known or not. We illustrate the approach with West Nile virus, a globally-spreading zoonotic arbovirus. Though our analytical results are based on a linearization of the dynamical systems, the sampling rules appear robust over a wide range of parameter space when compared to nonlinear simulation models. Our results suggest some simple rules that can be used by practitioners when developing surveillance programs. These rules require knowledge of transition rates between epidemiological compartments, which population was initially infected, and of the cost per sample for serological tests.
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[Appendiceal diverticulitis: comparative study of 7 cases versus 442 acute appendicitis].
Acta Gastroenterol. Latinoam.
PUBLISHED: 05-23-2014
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Appendiceal diverticulitis (AD) is a rare cause of acute appendicitis (AA) which is most frequently diagnosed after appendectomy in pathological study.
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Diagnostic accuracy of preoperative urinary smear test in patients with bladder urothelial carcinoma in a high-volume center.
Arch. Esp. Urol.
PUBLISHED: 05-21-2014
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To determine diagnostic accuracy of urinary cytology (smear test) in patients with preoperative diagnosis of urothelial bladder carcinoma.
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Importance of defining the best treatment of a genital gunshot wound: A case report.
World J Clin Cases
PUBLISHED: 05-03-2014
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Twenty percent of genital traumas are caused by penetrating injuries; accordingly gunshot and stab wounds have increased in the last couple of years around the globe, even in Colombia. A 67-year-old male patient was admitted to the emergency room because he received multiple gunshot wounds. On physical examination, multiple wounds on his penis with loss of tissue in the foreskin, glans, anterior urethra (distal third) and cavernous corpora were found. The urologist performed a partial penectomy with a penis reconstruction, he debrided the cutaneous flap of the dorsal foreskin and its glans, sutured the distal cavernous corpora and dissected the urethra. Penetrating genital injuries are extremely important due to their impact on the functional, psychological and the aesthetic consequences. It is necessary to define the best possible treatment to minimize the damage.
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Has beta-blocker use increased in patients with heart failure in internal medicine settings? Prognostic implications: RICA registry.
Rev Esp Cardiol (Engl Ed)
PUBLISHED: 04-30-2014
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Underuse of beta-blockers has been reported in elderly patients with heart failure. The aim of this study was to evaluate the current prescription of beta-blockers in the internal medicine setting, and its association with morbidity and mortality in heart failure patients.
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Endothelial retention and phenotype on carbonized cardiovascular implant surfaces.
Biomaterials
PUBLISHED: 04-23-2014
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Heart valve disease is an increasing clinical burden for which there is no effective treatment outside of prosthetic replacement. Over the last 20 years, clinicians have increasingly preferred the use of biological prosthetics to mechanical valves despite their superior durability because of the lifelong anticoagulation therapy that is required. Mechanical valve surface engineering has largely focused on being as non-thrombogenic as possible, but despite decades of iteration has had insufficient impact on the anticoagulation burden. In this study, we systematically evaluate the potential for endothelialization of the pyrolytic carbon surface used in mechanical valves. We compared adsorbed adhesion ligand type (collagen I, fibronectin, laminin, and purified adhesion domain fragments GFOGER and FN7-10) and concentration on endothelial adhesion rates and adhesion strength on Medtronic-Hall prosthetic valve surfaces. Regardless of ligand type or concentration, endothelial adhesion strengthening was insufficient for their intended ultra-high shear stress environment. We then hypothesized that microfabricated trenches would reduce shear stress to tolerable levels while maintaining endothelial access to the flow stream, thereby promoting a confluent and anticoagulant endothelial monolayer. Computational fluid dynamics simulations predicted an empirical relationship of channel width, depth, and spacing that would maintain interior surface shear stress within tolerable levels. Endothelial cells seeded to confluence in these channels retained a confluent monolayer when exposed to 600 dyn/cm(2) shear stress for 48 h regardless of applied adhesive ligand. Furthermore, sheared EC expressed a mature anti-coagulant profile, including endothelial nitric oxide synthase (eNOS), VE-cadherin, and significantly downregulated plasminogen activator inhibitor-1 (PAI-1). As a final test, channeled pyrolytic carbon surfaces with confluent EC reduced human platelet adhesion 1000-fold over pyrolytic carbon alone. These results advance a promising biohybrid approach to enable active moderation of local coagulative response in mechanical heart valves, which could significantly extend the utility of this important treatment for heart valve disease.
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Flow cytometry in mastocytosis: utility as a diagnostic and prognostic tool.
Immunol Allergy Clin North Am
PUBLISHED: 04-22-2014
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This article presents information for the identification and characterization of mast cells from bone marrow and other tissues using multiparametric flow cytometry. In addition, it provides guidelines for the application of this technique in the subclassification of systemic mastocytosis and assessment of the long-term prognosis of patients individually.
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The modulation of cardiac progenitor cell function by hydrogel-dependent Notch1 activation.
Biomaterials
PUBLISHED: 04-07-2014
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Myocardial infarction is the leading cause of death worldwide and phase I clinical trials utilizing cardiac progenitor cells (CPCs) have shown promising outcomes. Notch1 signaling plays a critical role in cardiac development and in the survival, cardiogenic lineage commitment, and differentiation of cardiac stem/progenitor cells. In this study, we functionalized self-assembling peptide (SAP) hydrogels with a peptide mimic of the Notch1 ligand Jagged1 (RJ) to evaluate the therapeutic benefit of CPC delivery in the hydrogels in a rat model of myocardial infarction. The behavior of CPCs cultured in the 3D hydrogels in vitro including gene expression, proliferation, and growth factor production was evaluated. Interestingly, we observed Notch1 activation to be dependent on hydrogel polymer density/stiffness with synergistic increase in presence of RJ. Our results show that RJ mediated Notch1 activation depending on hydrogel concentration differentially regulated cardiogenic gene expression, proliferation, and growth factor production in CPCs in vitro. In rats subjected to experimental myocardial infarction, improvement in acute retention and cardiac function was observed following cell therapy in RJ hydrogels compared to unmodified or scrambled peptide containing hydrogels. This study demonstrates the potential therapeutic benefit of functionalizing SAP hydrogels with RJ for CPC based cardiac repair.
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Quantifying cross-border movements and migrations for guiding the strategic planning of malaria control and elimination.
Malar. J.
PUBLISHED: 03-28-2014
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Identifying human and malaria parasite movements is important for control planning across all transmission intensities. Imported infections can reintroduce infections into areas previously free of infection, maintain 'hotspots' of transmission and import drug resistant strains, challenging national control programmes at a variety of temporal and spatial scales. Recent analyses based on mobile phone usage data have provided valuable insights into population and likely parasite movements within countries, but these data are restricted to sub-national analyses, leaving important cross-border movements neglected.
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BRCA1 Accelerates CtIP-Mediated DNA-End Resection.
Cell Rep
PUBLISHED: 03-18-2014
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DNA-end resection is a highly regulated and critical step in the response and repair of DNA double-strand breaks. In higher eukaryotes, CtIP regulates resection by integrating cellular signals via its posttranslational modifications and protein-protein interactions, including cell-cycle-controlled interaction with BRCA1. The role of BRCA1 in DNA-end resection is not clear. Here, we develop an assay to study DNA resection in higher eukaryotes at high resolution. We demonstrate that the BRCA1-CtIP interaction, albeit not essential for resection, modulates the speed at which this process takes place.
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Microgel film dynamics modulate cell adhesion behavior.
Soft Matter
PUBLISHED: 03-18-2014
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A material's mechanical properties greatly control cell behavior at the cell–substrate interface. In this work, we demonstrate that microgel multilayers have unique elastic and viscoelastic-like properties that can be modulated to produce morphological changes in fibroblasts cultured on the film. Protein adsorption is also examined and the data are contrasted with the number of cells adhered. The dynamic interaction of cell and substrate is only partially explained by conventional understanding of surface–receptor interactions and substrate elasticity. Viscoelasticity, a mechanical property not often considered, plays a significant role at cellular length and time scales for microgel films.
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Vascular Imaging Before Intravenous Thrombolysis: Consequences of In-Hospital Delay in Applying Two Diagnostic Procedures.
J Neuroimaging
PUBLISHED: 03-14-2014
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Vascular imaging is increasingly used for diagnosis of arterial occlusions in acute ischemic stroke (AIS) patients. Our aim was to determine whether computed tomography angiography (CTA) and Doppler/duplex ultrasound (DUS) before intravenous thrombolysis (IVT) is associated with a delay in time-to-treatment.
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Microfluidic-based generation of size-controlled, biofunctionalized synthetic polymer microgels for cell encapsulation.
Adv. Mater. Weinheim
PUBLISHED: 03-11-2014
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Cell and islet microencapsulation in synthetic hydrogels provides an immunoprotective and cell-supportive microenvironment. A microfluidic strategy for the genaration of biofunctionalized, synthetic microgel particles with precise control over particle size and molecular permeability for cell and protein delivery is presented. These engineered capsules support high cell viability and function of encapsulated human stem cells and islets.
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Living biointerfaces based on non-pathogenic bacteria to direct cell differentiation.
Sci Rep
PUBLISHED: 03-07-2014
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Genetically modified Lactococcus lactis, non-pathogenic bacteria expressing the FNIII(7-10) fibronectin fragment as a protein membrane have been used to create a living biointerface between synthetic materials and mammalian cells. This FNIII(7-10) fragment comprises the RGD and PHSRN sequences of fibronectin to bind ?5?1 integrins and triggers signalling for cell adhesion, spreading and differentiation. We used L. lactis strain to colonize material surfaces and produce stable biofilms presenting the FNIII(7-10) fragment readily available to cells. Biofilm density is easily tunable and remains stable for several days. Murine C2C12 myoblasts seeded over mature biofilms undergo bipolar alignment and form differentiated myotubes, a process triggered by the FNIII(7-10) fragment. This biointerface based on living bacteria can be further modified to express any desired biochemical signal, establishing a new paradigm in biomaterial surface functionalisation for biomedical applications.
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Necrobiosis lipoidica.
Aust Fam Physician
PUBLISHED: 03-07-2014
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Necrobiosis lipoidica presents with a distinctive appearance making it an important clinical diagnosis.
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Recasting the theory of mosquito-borne pathogen transmission dynamics and control.
Trans. R. Soc. Trop. Med. Hyg.
PUBLISHED: 03-03-2014
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Mosquito-borne diseases pose some of the greatest challenges in public health, especially in tropical and sub-tropical regions of the world. Efforts to control these diseases have been underpinned by a theoretical framework developed for malaria by Ross and Macdonald, including models, metrics for measuring transmission, and theory of control that identifies key vulnerabilities in the transmission cycle. That framework, especially Macdonald's formula for R0 and its entomological derivative, vectorial capacity, are now used to study dynamics and design interventions for many mosquito-borne diseases. A systematic review of 388 models published between 1970 and 2010 found that the vast majority adopted the Ross-Macdonald assumption of homogeneous transmission in a well-mixed population. Studies comparing models and data question these assumptions and point to the capacity to model heterogeneous, focal transmission as the most important but relatively unexplored component in current theory. Fine-scale heterogeneity causes transmission dynamics to be nonlinear, and poses problems for modeling, epidemiology and measurement. Novel mathematical approaches show how heterogeneity arises from the biology and the landscape on which the processes of mosquito biting and pathogen transmission unfold. Emerging theory focuses attention on the ecological and social context for mosquito blood feeding, the movement of both hosts and mosquitoes, and the relevant spatial scales for measuring transmission and for modeling dynamics and control.
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In vivo fluorescence imaging of biomaterial-associated inflammation and infection in a minimally invasive manner.
J Biomed Mater Res A
PUBLISHED: 03-01-2014
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Implant-associated inflammation and bacterial infection severely limit the functional performance of medical devices and are a major cause of implant failure. Therefore, it is crucial to develop methodologies to monitor/image implant-associated aseptic inflammation and bacterial infection in a minimally invasive manner. Here, we exploited near-infrared fluorescence (NIRF) molecular probes injected locally at the implant site to perform minimally invasive, simultaneous imaging of inflammation, and infection associated with implanted polymer disks. The hydro-sulfo-Cy5 (H-s-Cy5) probe detected reactive oxygen species associated with inflammatory responses to both aseptic and biofilm-containing implants, whereas diaminocyanine sulfonate selectively detected nitric oxide associated with a biofilm on the biomaterial at acute time points (<4 days). This imaging modality also allows longitudinal monitoring because of high specificity and fast clearance rate of the fluorescent probes. Taken together, these NIRF molecular probes represent a useful tool to directly image inflammatory responses and infections associated with implanted devices for the diagnosis of device-associated inflammation and infection as well as the development of effective therapies. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2014.
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Near-infrared fluorescence imaging as an alternative to bioluminescent bacteria to monitor biomaterial-associated infections.
Acta Biomater
PUBLISHED: 02-13-2014
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Biomaterial-associated infection is one of the most common complications related to the implantation of any biomedical device. Several in vivo imaging platforms have emerged as powerful diagnostic tools to longitudinally monitor biomaterial-associated infections in small animal models. In this study, we directly compared two imaging approaches: bacteria engineered to produce luciferase to generate bioluminescence and reactive oxygen species (ROS) imaging of the inflammatory response associated with the infected implant. We performed longitudinal imaging of bioluminescence associated with bacteria strains expressing plasmid-integrated luciferase driven by different promoters or a strain with the luciferase gene integrated into the chromosome. These luminescent strains provided an adequate signal for acute (0-4 days) monitoring of the infection, but the bioluminescence signal decreased over time and leveled off at 7 days post-implantation. This loss in the bioluminescence signal was attributed to changes in the metabolic activity of the bacteria. In contrast, near-infrared fluorescence imaging of ROS associated with inflammation to the implant provided sensitive and dose-dependent signals of biomaterial-associated bacteria. ROS imaging exhibited higher sensitivity than the bioluminescence imaging and was independent of the bacteria strain. Near-infrared fluorescence imaging of inflammatory responses represents a powerful alternative to bioluminescence imaging for monitoring biomaterial-associated bacterial infections.
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Optimal protocol for PTEN immunostaining; role of analytical and preanalytical variables in PTEN staining in normal and neoplastic endometrial, breast, and prostatic tissues.
Hum. Pathol.
PUBLISHED: 01-25-2014
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In some tumors, phosphatase and tensin homolog (PTEN) inactivation may have prognostic importance and predictive value for targeted therapies. Immunohistochemistry (IHC) may be an effective method to demonstrate PTEN loss. It was claimed that PTEN IHC showed poor reproducibility, lack of standardization, and variable effects of preanalytical factors. In this study, we developed an optimal protocol for PTEN IHC, with clone 6H2.1, by checking the relevance of analytical variables in normal tissue and tumors of endometrium, breast, and prostate. Pattern and intensity of cellular staining and background nonspecific staining were quantified and subjected to statistical analysis by linear mixed models. The proposed protocol showed a statistically best performance (P < .05) and included a high target retrieval solution, 1:100 primary antibody dilution (2.925 mg/L), FLEX diluent, and EnVisionFLEX+ detection method, with a sensitivity and specificity of 72.33% and 78.57%, respectively. Staining specificity was confirmed in cell lines and animal models. Endometrial carcinomas with PTEN genetic abnormalities showed statistically lower staining than tumors without alterations (mean histoscores, 34.66 and 119.28, respectively; P = .01). Controlled preanalytical factors (delayed fixation and overfixation) did not show any statistically significant effect on staining with optimal protocol (P > .001). However, there was a trend of significance for decreased staining and fixation under high temperature. Moreover, staining was better in endometrial aspirates than in matched hysterectomy specimens, subjected to less controlled preanalytical variables (mean histoscores, 80 and 40, respectively; P = .002). A scoring system combining intensity of staining and percentage of positive cells was statistically associated with PTEN alterations (P = .01).
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Nanoengineered particles for enhanced intra-articular retention and delivery of proteins.
Adv Healthc Mater
PUBLISHED: 01-24-2014
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Localized intra-articular delivery of anti-inflammatory proteins can reduce inflammation in osteoarthritis but poses a challenge because of raid clearance within few hours of injection. A new class of polymer is developed that forms self-assembled nanoparticles ranging from 300 to 900 nm and demonstrates particle size dependent prolonged retention in intra-articular joint spaces compared to bolus protein over a period of 14 d.
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Bone regeneration using an alpha 2 beta 1 integrin-specific hydrogel as a BMP-2 delivery vehicle.
Biomaterials
PUBLISHED: 01-23-2014
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Non-healing bone defects present tremendous socioeconomic costs. Although successful in some clinical settings, bone morphogenetic protein (BMP) therapies require supraphysiological dose delivery for bone repair, raising treatment costs and risks of complications. We engineered a protease-degradable poly(ethylene glycol) (PEG) synthetic hydrogel functionalized with a triple helical, ?2?1 integrin-specific peptide (GFOGER) as a BMP-2 delivery vehicle. GFOGER-functionalized hydrogels lacking BMP-2 directed human stem cell differentiation and produced significant enhancements in bone repair within a critical-sized bone defect compared to RGD hydrogels or empty defects. GFOGER functionalization was crucial to the BMP-2-dependent healing response. Importantly, these engineered hydrogels outperformed the current clinical carrier in repairing non-healing bone defects at low BMP-2 doses. GFOGER hydrogels provided sustained in vivo release of encapsulated BMP-2, increased osteoprogenitor localization in the defect site, enhanced bone formation and induced defect bridging and mechanically robust healing at low BMP-2 doses which stimulated almost no bone regeneration when delivered from collagen sponges. These findings demonstrate that GFOGER hydrogels promote bone regeneration in challenging defects with low delivered BMP-2 doses and represent an effective delivery vehicle for protein therapeutics with translational potential.
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Biofunctional hydrogels for skeletal muscle constructs.
J Tissue Eng Regen Med
PUBLISHED: 01-22-2014
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Hydrogel scaffolds encapsulating C2C12 mouse skeletal muscle cells have been engineered as in vitro constructs towards regenerative medicine therapies for the enhancement and inducement of functional skeletal muscle formation. Previous work has largely involved two-dimensional (2D) muscle strips, naturally occurring hydrogels and incomplete examination of the effects of the scaffold and/or biological functionalization on myogenic differentiation in a controllable manner. The goal of this study was to identify key properties in functionalized poly(ethylene glycol) (PEG)-maleimide (MAL) synthetic hydrogels that promote cell attachment, proliferation and differentiation for the formation of multinucleated myotubes and functional skeletal muscle tissue constructs. Significant differences in myoblast viability were observed as a function of cell seeding density, polymer weight percentage and bioadhesive ligands. The identified optimized conditions for cell survival, required for myotube development, were carried over for differentiation assays. PEG hydrogels (5% weight/volume), functionalized with 2.0?mm RGD adhesive peptide and crosslinked with protease-cleavable peptides, incubated for 3?days before supplementation with 2% horse serum, significantly increased expression of differentiated skeletal muscle markers by 50%; 17% more multinucleated cells and a 40% increase in the number of nuclei/differentiated cell compared to other conditions. Functionality of cell-laden hydrogels was demonstrated by a 20% decrease in the extruded length of the hydrogel when stimulated with a contractile agent, compared to 7% for a saline control. This study provided strategies to engineer a three-dimensional (3D) microenvironment, using synthetic hydrogels to promote the development of differentiated muscle tissue from skeletal muscle progenitor cells to form contractile units. Copyright © 2014 John Wiley & Sons, Ltd.
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High fidelity nanopatterning of proteins onto well-defined surfaces through subtractive contact printing.
Methods Cell Biol.
PUBLISHED: 01-21-2014
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In the pursuit to develop enhanced technologies for cellular bioassays as well as understand single cell interactions with its underlying substrate, the field of biotechnology has extensively utilized lithographic techniques to spatially pattern proteins onto surfaces in user-defined geometries. Microcontact printing (?CP) remains an incredibly useful patterning method due to its inexpensive nature, scalability, and the lack of considerable use of specialized clean room equipment. However, as new technologies emerge that necessitate various nano-sized areas of deposited proteins, traditional ?CP methods may not be able to supply users with the needed resolution size. Recently, our group developed a modified "subtractive ?CP" method which still retains many of the benefits offered by conventional ?CP. Using this technique, we have been able to reach resolution sizes of fibronectin as small as 250 nm in largely spaced arrays for cell culture. In this communication, we present a detailed description of our subtractive ?CP procedure that expands on many of the little tips and tricks that together make this procedure an easy and effective method for controlling protein patterning.
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Predictive factors for mortality in Fournier' gangrene: A serie of 59 cases.
Cir Esp
PUBLISHED: 01-20-2014
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Fournier's gangrene (FG) is the necrotizing fasciitis of the perineum and genital area and presents a high mortality rate. The aim was to assess prognostic factors for mortality, create a new mortality predictive scale and compare it with previously published scales in patients diagnosed with FG in our Emergency Department.
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Semi-synthesis of acylated triterpenes from olive-oil industry wastes for the development of anticancer and anti-HIV agents.
Eur J Med Chem
PUBLISHED: 01-08-2014
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A broad set of potential bioactive conjugate compounds has been semi-synthesized through solution- and solid-phase organic procedures, coupling two natural pentacyclic triterpene acids, oleanolic (OA) and maslinic acids (MA), at the hydroxyl groups of the A-ring of the triterpene skeleton, with 10 different acyl groups. These acyl OA and MA derivatives have been tested for their anti-proliferative (against the b16f10 murine melanoma cancer cells) and antiviral (as inhibitors of the HIV-1-protease) effects. Several derivatives have shown high levels of early and total apoptosis (up to 90%). Most of the compounds that exhibited anti-proliferative effects also generated ROS, probably involving the activation of an intrinsic apoptotic route. The only four compounds that did not cause the release of ROS could be related to the participation of a probable extrinsic activation of the apoptosis mechanism. A great number of these acyl OA and MA derivatives have proved to be potent inhibitors of the HIV-1-protease, the most active inhibitors having IC50 values between 0.31 and 15.6 ?M, these values being between 4 and 186 times lower than their non-acylated precursors. The potent activities exhibited in the apoptosis-activation processes and in the inhibition of the HIV-1-protease by some OA and MA acylated derivatives imply that these compounds could be used as new, safe, and effective anticancer and/or antiviral drugs.
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Nocebo effect in randomized clinical trials of antidepressants in children and adolescents: systematic review and meta-analysis.
Front Behav Neurosci
PUBLISHED: 01-01-2014
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To compare the incidence of adverse events between active and placebo arms of randomized clinical trials in depressive children and adolescents (C&A) with antidepressant treatments, in order to look for similarities in both groups that allow to establish a possible nocebo effect.
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Identification of critical regions and candidate genes for cardiovascular malformations and cardiomyopathy associated with deletions of chromosome 1p36.
PLoS ONE
PUBLISHED: 01-01-2014
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Cardiovascular malformations and cardiomyopathy are among the most common phenotypes caused by deletions of chromosome 1p36 which affect approximately 1 in 5000 newborns. Although these cardiac-related abnormalities are a significant source of morbidity and mortality associated with 1p36 deletions, most of the individual genes that contribute to these conditions have yet to be identified. In this paper, we use a combination of clinical and molecular cytogenetic data to define five critical regions for cardiovascular malformations and two critical regions for cardiomyopathy on chromosome 1p36. Positional candidate genes which may contribute to the development of cardiovascular malformations associated with 1p36 deletions include DVL1, SKI, RERE, PDPN, SPEN, CLCNKA, ECE1, HSPG2, LUZP1, and WASF2. Similarly, haploinsufficiency of PRDM16-a gene which was recently shown to be sufficient to cause the left ventricular noncompaction-SKI, PRKCZ, RERE, UBE4B and MASP2 may contribute to the development of cardiomyopathy. When treating individuals with 1p36 deletions, or providing prognostic information to their families, physicians should take into account that 1p36 deletions which overlie these cardiac critical regions may portend to cardiovascular complications. Since several of these cardiac critical regions contain more than one positional candidate gene-and large terminal and interstitial 1p36 deletions often overlap more than one cardiac critical region-it is likely that haploinsufficiency of two or more genes contributes to the cardiac phenotypes associated with many 1p36 deletions.
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Distinct biophysical mechanisms of focal adhesion kinase mechanoactivation by different extracellular matrix proteins.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 11-12-2013
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Matrix mechanics controls cell fate by modulating the bonds between integrins and extracellular matrix (ECM) proteins. However, it remains unclear how fibronectin (FN), type 1 collagen, and their receptor integrin subtypes distinctly control force transmission to regulate focal adhesion kinase (FAK) activity, a crucial molecular signal governing cell adhesion/migration. Here we showed, using a genetically encoded FAK biosensor based on fluorescence resonance energy transfer, that FN-mediated FAK activation is dependent on the mechanical tension, which may expose its otherwise hidden FN synergy site to integrin ?5. In sharp contrast, the ligation between the constitutively exposed binding motif of type 1 collagen and its receptor integrin ?2 was surprisingly tension-independent to induce sufficient FAK activation. Although integrin ? subunit determines mechanosensitivity, the ligation between ? subunit and the ECM proteins converges at the integrin ?1 activation to induce FAK activation. We further discovered that the interaction of the N-terminal protein 4.1/ezrin/redixin/moesin basic patch with phosphatidylinositol 4,5-biphosphate is crucial during cell adhesion to maintain the FAK activation from the inhibitory effect of nearby protein 4.1/ezrin/redixin/moesin acidic sites. Therefore, different ECM proteins either can transmit or can shield from mechanical forces to regulate cellular functions, with the accessibility of ECM binding motifs by their specific integrin ? subunits determining the biophysical mechanisms of FAK activation during mechanotransduction.
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Cellular encapsulation enhances cardiac repair.
J Am Heart Assoc
PUBLISHED: 10-12-2013
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Stem cells for cardiac repair have shown promise in preclinical trials, but lower than expected retention, viability, and efficacy. Encapsulation is one potential strategy to increase viable cell retention while facilitating paracrine effects.
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Nanofiber orientation and surface functionalization modulate human mesenchymal stem cell behavior in vitro.
Tissue Eng Part A
PUBLISHED: 10-12-2013
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Electrospun nanofiber meshes have emerged as a new generation of scaffold membranes possessing a number of features suitable for tissue regeneration. One of these features is the flexibility to modify their structure and composition to orchestrate specific cellular responses. In this study, we investigated the effects of nanofiber orientation and surface functionalization on human mesenchymal stem cell (hMSC) migration and osteogenic differentiation. We used an in vitro model to examine hMSC migration into a cell-free zone on nanofiber meshes and mitomycin C treatment to assess the contribution of proliferation to the observed migration. Poly (?-caprolactone) meshes with oriented topography were created by electrospinning aligned nanofibers on a rotating mandrel, while randomly oriented controls were collected on a stationary collector. Both aligned and random meshes were coated with a triple-helical, type I collagen-mimetic peptide, containing the glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) motif. Our results indicate that nanofiber GFOGER peptide functionalization and orientation modulate cellular behavior, individually, and in combination. GFOGER significantly enhanced the migration, proliferation, and osteogenic differentiation of hMSCs on nanofiber meshes. Aligned nanofiber meshes displayed increased cell migration along the direction of fiber orientation compared to random meshes; however, fiber alignment did not influence osteogenic differentiation. Compared to each other, GFOGER coating resulted in a higher proliferation-driven cell migration, whereas fiber orientation appeared to generate a larger direct migratory effect. This study demonstrates that peptide surface modification and topographical cues associated with fiber alignment can be used to direct cellular behavior on nanofiber mesh scaffolds, which may be exploited for tissue regeneration.
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Retrospective multicenter study of 230 6-mm SLA-surfaced implants with 1- to 6-year follow-up.
Int J Oral Maxillofac Implants
PUBLISHED: 09-26-2013
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Using short implants poses a challenge in implant surgery. Implant surfaces have evolved, making it possible to improve the success of short implants substantially. However, there is still little information about the long-term predictability achieved with short, rough-surfaced implants. The objective of this study was to evaluate the long-term survival rate of 6-mm rough implants.
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The demographics of human and malaria movement and migration patterns in East Africa.
Malar. J.
PUBLISHED: 08-06-2013
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The quantification of parasite movements can provide valuable information for control strategy planning across all transmission intensities. Mobile parasite carrying individuals can instigate transmission in receptive areas, spread drug resistant strains and reduce the effectiveness of control strategies. The identification of mobile demographic groups, their routes of travel and how these movements connect differing transmission zones, potentially enables limited resources for interventions to be efficiently targeted over space, time and populations.
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PHACOS, a functionalized bacterial polyester with bactericidal activity against methicillin-resistant Staphylococcus aureus.
Biomaterials
PUBLISHED: 07-26-2013
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Biomaterial-associated infections represent a significant clinical problem, and treatment of these microbial infections is becoming troublesome due to the increasing number of antibiotic-resistant strains. Here, we report a naturally functionalized bacterial polyhydroxyalkanoate (PHACOS) with antibacterial properties. We demonstrate that PHACOS selectively and efficiently inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) both in vitro and in vivo. This ability has been ascribed to the functionalized side chains containing thioester groups. Significantly less (3.2-fold) biofilm formation of S. aureus was detected on PHACOS compared to biofilms formed on control poly(3-hydroxyoctanoate-co-hydroxyhexanoate) and poly(ethylene terephthalate), but no differences were observed in bacterial adhesion among these polymers. PHACOS elicited minimal cytotoxic and inflammatory effects on murine macrophages and supported normal fibroblast adhesion. In vivo fluorescence imaging demonstrated minimal inflammation and excellent antibacterial activity for PHACOS compared to controls in an in vivo model of implant-associated infection. Additionally, reductions in neutrophils and macrophages in the vicinity of sterile PHACOS compared to sterile PHO implant were observed by immunohistochemistry. Moreover, a similar percentage of inflammatory cells was found in the tissue surrounding sterile PHACOS and S. aureus pre-colonized PHACOS implants, and these levels were significantly lower than S. aureus pre-colonized control polymers. These findings support a contact active surface mode of antibacterial action for PHACOS and establish this functionalized polyhydroxyalkanoate as an infection-resistant biomaterial.
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Inhibition of matrix metalloproteinase-9 and nuclear factor kappa B contribute to melatonin prevention of motility and invasiveness in HepG2 liver cancer cells.
J. Pineal Res.
PUBLISHED: 07-25-2013
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Hepatocellular carcinoma (HCC) is one of the most lethal human cancers worldwide because of its high incidence and its metastatic potential. Extracellular matrix degradation by matrix metalloproteinases (MMPs) has been connected with cancer cell invasion, and it has been suggested that inhibition of MMPs by synthetic and natural inhibitors may be of great importance in the HCC therapies. Melatonin, the main product of the pineal gland, exerts antiproliferative, proapoptotic, and antiangiogenic properties in HepG2 human hepatocellular cells, and exhibits anti-invasive and antimetastatic activities by suppressing the enzymatic activity of MMP-9 in different tumor types. However, the underlying mechanism of anti-invasive activity in HCC models has not been fully elucidated. Here, we demonstrate that 1 mm melatonin dosage reduced in IL-1?-induced HepG2 cells MMP-9 gelatinase activity and inhibited cell invasion and motility through downregulation of MMP-9 gene expression and upregulation of the MMP-9-specific inhibitor tissue inhibitor of metalloproteinases (TIMP)-1. No significant changes were observed in the expression and activity of MMP-2, the other proteinase implicated in matrix collagen degradation, and its tissue inhibitor, TIMP-2. Also, melatonin significantly suppressed IL-1?-induced nuclear factor-kappaB (NF-?B) translocation and transcriptional activity. In summary, we demonstrate that melatonin modulates motility and invasiveness of HepG2 cell in vitro through a molecular mechanism that involves TIMP-1 upregulation and attenuation of MMP-9 expression and activity via NF-?B signal pathway inhibition.
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Millennium development health metrics: where do Africas children and women of childbearing age live?
Popul Health Metr
PUBLISHED: 07-11-2013
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The Millennium Development Goals (MDGs) have prompted an expansion in approaches to deriving health metrics to measure progress toward their achievement. Accurate measurements should take into account the high degrees of spatial heterogeneity in health risks across countries, and this has prompted the development of sophisticated cartographic techniques for mapping and modeling risks. Conversion of these risks to relevant population-based metrics requires equally detailed information on the spatial distribution and attributes of the denominator populations. However, spatial information on age and sex composition over large areas is lacking, prompting many influential studies that have rigorously accounted for health risk heterogeneities to overlook the substantial demographic variations that exist subnationally and merely apply national-level adjustments.Here we outline the development of high resolution age- and sex-structured spatial population datasets for Africa in 2000-2015 built from over a million measurements from more than 20,000 subnational units, increasing input data detail from previous studies by over 400-fold. We analyze the large spatial variations seen within countries and across the continent for key MDG indicator groups, focusing on children under 5 and women of childbearing age, and find that substantial differences in health and development indicators can result through using only national level statistics, compared to accounting for subnational variation.Progress toward meeting the MDGs will be measured through national-level indicators that mask substantial inequalities and heterogeneities across nations. Cartographic approaches are providing opportunities for quantitative assessments of these inequalities and the targeting of interventions, but demographic spatial datasets to support such efforts remain reliant on coarse and outdated input data for accurately locating risk groups. We have shown here that sufficient data exist to map the distribution of key vulnerable groups, and that doing so has substantial impacts on derived metrics through accounting for spatial demographic heterogeneities that exist within nations across Africa.
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Sentinel node biopsy for melanoma. Analysis of our experience (125 patients).
Cir Esp
PUBLISHED: 06-01-2013
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The objective of this study is to analyze our experience in the use of sentinel node biopsy (SNB) in melanoma and identify the predictive factors of positive SNB and multiple drainage.
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How vinculin regulates force transmission.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 05-28-2013
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Focal adhesions mediate force transfer between ECM-integrin complexes and the cytoskeleton. Although vinculin has been implicated in force transmission, few direct measurements have been made, and there is little mechanistic insight. Using vinculin-null cells expressing vinculin mutants, we demonstrate that vinculin is not required for transmission of adhesive and traction forces but is necessary for myosin contractility-dependent adhesion strength and traction force and for the coupling of cell area and traction force. Adhesion strength and traction forces depend differentially on vinculin head (V(H)) and tail domains. V(H) enhances adhesion strength by increasing ECM-bound integrin-talin complexes, independently from interactions with vinculin tail ligands and contractility. A full-length, autoinhibition-deficient mutant (T12) increases adhesion strength compared with VH, implying roles for both vinculin activation and the actin-binding tail. In contrast to adhesion strength, vinculin-dependent traction forces absolutely require a full-length and activated molecule; V(H) has no effect. Physical linkage of the head and tail domains is required for maximal force responses. Residence times of vinculin in focal adhesions, but not T12 or V(H), correlate with applied force, supporting a mechanosensitive model for vinculin activation in which forces stabilize vinculins active conformation to promote force transfer.
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PEG-Maleimide Hydrogels for Protein and Cell Delivery in Regenerative Medicine.
Ann Biomed Eng
PUBLISHED: 05-08-2013
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Protein- and cell-based therapies represent highly promising strategies for regenerative medicine, immunotherapy, and oncology. However, these therapies are significantly limited by delivery considerations, particularly in terms of protein stability and dosing kinetics as well as cell survival, engraftment, and function. Hydrogels represent versatile and robust delivery vehicles for proteins and cells due to their high water content that retains protein biological activity, high cytocompatibility and minimal adverse host reactions, flexibility and tunability in terms of chemistry, structure, and polymerization format, ability to incorporate various biomolecules to convey biofunctionality, and opportunity for minimally invasive delivery as injectable carriers. This review highlights recent progress in the engineering of poly(ethylene glycol) hydrogels cross-linked using maleimide reactive groups for protein and cell delivery.
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Host response to microgel coatings on neural electrodes implanted in the brain.
J Biomed Mater Res A
PUBLISHED: 04-15-2013
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The performance of neural electrodes implanted in the brain is often limited by host response in the surrounding brain tissue, including astrocytic scar formation, neuronal cell death, and inflammation around the implant. We applied conformal microgel coatings to silicon neural electrodes and examined host responses to microgel-coated and uncoated electrodes following implantation in the rat brain. In vitro analyses demonstrated significantly reduced astrocyte and microglia adhesion to microgel-coated electrodes compared to uncoated controls. Microgel-coated and uncoated electrodes were implanted in the rat brain cortex and the extent of activated microglia and astrocytes as well as neuron density around the implant were evaluated at 1, 4, and 24 weeks postimplantation. Microgel coatings reduced astrocytic recruitment around the implant at later time points. However, microglial response indicated persistence of inflammation in the area around the electrode. Neuronal density around the implanted electrodes was also lower for both implant groups compared to the uninjured control. These results demonstrate that microgel coatings do not significantly improve host responses to implanted neural electrodes and underscore the need for further improvements in implantable materials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
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Dynamic cell-adhesive microenvironments and their effect on myogenic differentiation.
Acta Biomater
PUBLISHED: 04-12-2013
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Integrin-mediated cell adhesion plays a central role in cell behavior on biomaterial surfaces and influences various cell functions. Photoactivatable RGD adhesive peptides were used to investigate the effect of the density and time point of bioadhesive ligand presentation on cell adhesion, proliferation and differentiation. PEGylated self-assembled monolayers were functionalized with RGD and caged RGD ligands and seeded with C2C12 myoblasts. The cultures were irradiated at various time points between 1 and 48 h after cell seeding in order to increase RGD surface concentration at defined time points. Attachment, spreading and myogenic differentiation of C2C12 myoblasts strongly varied with the density of RGD at the surface. Proliferation and myogenesis were further regulated by the time point at which RGD was presented to the cell, reaching highest levels when RGD exposure occurred?6 h after cell seeding. These results provide fundamental insights in cell-biomaterial interactions of C2C12 myoblasts in terms of temporal integrin-mediated cell responses.
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Antiallodynic and analgesic effects of maslinic acid, a pentacyclic triterpenoid from Olea europaea.
J. Nat. Prod.
PUBLISHED: 03-29-2013
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The effects of maslinic acid (1), a pentacyclic triterpenoid obtained from Olea europaea, were studied in several tests for nociception in mice. Systemic administration of 1 reduced acetic acid-induced writhing, the inflammatory phase of formalin-induced pain, and capsaicin-induced mechanical allodynia. However, it did not induce motor incoordination in the rotarod test. The topical administration of 1 also reduced the inflammatory phase of the formalin test, indicating that at least some of its effects are mediated peripherally. The present results demonstrate for the first time that maslinic acid induces antinociceptive and antiallodynic effects.
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Biotransformation of oleanolic and maslinic acids by Rhizomucor miehei.
Phytochemistry
PUBLISHED: 03-12-2013
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Microbial transformation of oleanolic acid by Rhizomucor miehei produced three metabolites. A known compound, a 30-hydroxyl derivative (queretaroic acid), and two 7?,30- and 1?,30-dihydroxylated metabolites, respectively. The action of the same fungus (R. miehei) on maslinic acid produced an olean-11-en-28,13?-olide derivative, a metabolite hydroxylated at C-30, an 11-oxo derivative, and two metabolites with an 11?,12?-epoxy group, hydroxylated or not at C-30. Their structures were elucidated by extensive analyses of their spectroscopic data, and also by chemical correlations.
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Why do cervids feed on aquatic vegetation?
Behav. Processes
PUBLISHED: 03-08-2013
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Consumption of aquatic plants is rare among cervids, despite the common occurrence of this form of vegetation. However, the paucity of literature reporting on this feeding behaviour suggests that Na (but also other minerals), protein, and the ubiquitous availability of aquatic vegetation may play a role in its consumption. We present results quantifying those factors that regulate the consumption of aquatic plants in the Iberian red deer. We focussed our study primarily on two questions: (i) what nutritional values are red deer seeking in the aquatic plants?; and (ii) why do red deer primarily use aquatic plants during the summer? A comparison of the seasonal variations in Na content between terrestrial vs. aquatic vegetation did not fully support the hypothesis that aquatic plants are being consumed more in summer because of any seasonal variation in Na availability. The Na content in the aquatic vegetation was adequate all the year-round; whereas, the Na content in the terrestrial vegetation was consistently deficient. However, a greater summer content of essential minerals and protein in the aquatic vegetation may be the cause for their consumption exclusively during the summer. We suggest that seasonal variations in the consumption of aquatic vegetation by cervids is primarily driven by temporal variations in the nutrient content, combined with seasonal variations in the physiological demands for these nutrients.
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Adhesion strength-based, label-free isolation of human pluripotent stem cells.
Nat. Methods
PUBLISHED: 03-07-2013
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We demonstrate substantial differences in adhesive signature between human pluripotent stem cells (hPSCs), partially reprogrammed cells, somatic cells and hPSC-derived differentiated progeny. We exploited these differential adhesion strengths to rapidly (over ?10 min) and efficiently isolate fully reprogrammed induced hPSCs (hiPSCs) as intact colonies from heterogeneous reprogramming cultures and from differentiated progeny using microfluidics. hiPSCs were isolated label free, enriched to 95%-99% purity with >80% survival, and had normal transcriptional profiles, differentiation potential and karyotypes. We also applied this strategy to isolate hPSCs (hiPSCs and human embryonic stem cells) during routine culture and show that it may be extended to isolate hPSC-derived lineage-specific stem cells or differentiated cells.
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Functional living biointerphases.
Adv Healthc Mater
PUBLISHED: 02-28-2013
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Lactococcus lactis is modified to express a fibronectin fragment (FNIII????) as a membrane protein. This interphase, based on a living system, can be further exploited to provide spatio-temporal factors to direct cell function at the material interface. This approach establishes a new paradigm in biomaterial surface functionalization for biomedical applications.
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Vasculogenic bio-synthetic hydrogel for enhancement of pancreatic islet engraftment and function in type 1 diabetes.
Biomaterials
PUBLISHED: 02-15-2013
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Type 1 diabetes (T1DM) affects one in every 400 children and adolescents in the US. Due to the limitations of exogenous insulin therapy and whole pancreas transplantation, pancreatic islet transplantation has emerged as a promising therapy for T1DM. However, this therapy is severely limited by donor islet availability and poor islet engraftment and function. We engineered an injectable bio-synthetic, polyethylene glycol-maleimide hydrogel to enhance vascularization and engraftment of transplanted pancreatic islets in a mouse model of T1DM. Controlled presentation of VEGF-A and cell-adhesive peptides within this engineered material significantly improved the vascularization and function of islets delivered to the small bowel mesentery, a metabolically relevant site for insulin release. Diabetic mice receiving islets transplanted in proteolytically degradable hydrogels incorporating VEGF-A exhibited complete reversal of diabetic hyperglycemia with a 40% reduction in the number of islets required. Furthermore, hydrogel-delivered islets significantly improved weight gain, regulation of a glucose challenge, and intra-islet vascularization and engraftment compared to the clinical standard of islet infusion through the hepatic portal vein. This study establishes a simple biomaterial strategy for islet transplantation to promote enhanced islet engraftment and function.
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Gene expression profile of highly purified bone marrow mast cells in systemic mastocytosis.
J. Allergy Clin. Immunol.
PUBLISHED: 02-10-2013
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Despite the fact that a great majority (>90%) of patients with systemic mastocytosis (SM) carry a common genetic lesion, the D816V KIT mutation, little is known regarding the molecular and biological pathways underlying the clinical heterogeneity of the disease.
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Novel frem1-related mouse phenotypes and evidence of genetic interactions with gata4 and slit3.
PLoS ONE
PUBLISHED: 02-07-2013
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The FRAS1-related extracellular matrix 1 (FREM1) gene encodes an extracellular matrix protein that plays a critical role in the development of multiple organ systems. In humans, recessive mutations in FREM1 cause eye defects, congenital diaphragmatic hernia, renal anomalies and anorectal malformations including anteriorly placed anus. A similar constellation of findings-microphthalmia, cryptophthalmos, congenital diaphragmatic hernia, renal agenesis and rectal prolapse-have been described in FREM1-deficient mice. In this paper, we identify a homozygous Frem1 missense mutation (c.1687A>T, p.Ile563Phe) in an N-ethyl-N-nitrosourea (ENU)-derived mouse strain, crf11, with microphthalmia, cryptophthalmos, renal agenesis and rectal prolapse. This mutation affects a highly conserved residue in FREM1s third CSPG domain. The p.Ile563Phe change is predicted to be deleterious and to cause decreased FREM1 protein stability. The crf11 allele also fails to complement the previously described eyes2 allele of Frem1 (p.Lys826*) providing further evidence that the crf11 phenotype is due to changes affecting Frem1 function. We then use mice bearing the crf11 and eyes2 alleles to identify lung lobulation defects and decreased anogenital distance in males as novel phenotypes associated with FREM1 deficiency in mice. Due to phenotypic overlaps between FREM1-deficient mice and mice that are deficient for the retinoic acid-responsive transcription factor GATA4 and the extracellular matrix protein SLIT3, we also perform experiments to look for in vivo genetic interactions between the genes that encode these proteins. These experiments reveal that Frem1 interacts genetically with Gata4 in the development of lung lobulation defects and with Slit3 in the development of renal agenesis. These results demonstrate that FREM1-deficient mice faithfully recapitulate many of the phenotypes seen in individuals with FREM1 deficiency and that variations in GATA4 and SLIT3 expression modulate some FREM1-related phenotypes in mice.
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Engineering the matrix microenvironment for cell delivery and engraftment for tissue repair.
Curr. Opin. Biotechnol.
PUBLISHED: 02-04-2013
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Cell-based therapies represent promising strategies for tissue repair, particularly in cases in which host cells, due to disease, age, or excessive trauma, are unable to repair the defect or deficiency alone, even with additional delivered therapeutics. Current cell therapies fail to address long-term engraftment or delivery timing and location and result in modest improvements with long term engraftment rates of less than 1%. In many cell therapy applications, an appropriate carrier must be used to deliver transplanted cells and promote cell engraftment and function for a successful outcome by providing the appropriate microenvironment for the interactions between transplanted and host cells. This review highlights important considerations for engineering the microenvironment for cell delivery and engraftment in tissue repair.
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Liquid chromatography-mass spectrometry determination in plasma of maslinic acid, a bioactive compound from Olea europaea L.
Food Chem
PUBLISHED: 02-01-2013
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Maslinic acid, a pentacyclic triterpene from Olea europaea L., exerts hypoglycemic, antioxidant, cardioprotective and antitumoral activities. Here, an LC-APCI-MS method to determine this compound in plasma is presented as a first step in pharmacokinetic studies. Maslinic acid was extracted from plasma with ethyl acetate and separated on a C18 column using a gradient elution of water and acetonitrile. The target ions were m/z 471.3 for maslinic acid and m/z 455.3 for I.S. The method was validated by the analysis of spiked plasma samples obtaining a linear correlation, a recovery of 99.0±0.9% and a quantification limit of 5 nM. The precision and accuracy were ?8.38% and ?4.82%, respectively. Finally, the method was verified by measuring the rat plasmatic concentrations 24h after the single oral administration of 10, 25 and 50 mg/kg of maslinic acid, thereby ensuring that the procedure is appropriate for its use in bioavailability studies.
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Efficacy of antibiotic prophylaxis in patients undergoing cystoscopy: a randomized clinical trial.
World J Urol
PUBLISHED: 01-28-2013
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To establish the efficacy of antibiotic prophylaxis prior to cystoscopy in outpatients in decreasing the incidence of post-procedure urinary tract infection.
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An allelic series of mice reveals a role for RERE in the development of multiple organs affected in chromosome 1p36 deletions.
PLoS ONE
PUBLISHED: 01-24-2013
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Individuals with terminal and interstitial deletions of chromosome 1p36 have a spectrum of defects that includes eye anomalies, postnatal growth deficiency, structural brain anomalies, seizures, cognitive impairment, delayed motor development, behavior problems, hearing loss, cardiovascular malformations, cardiomyopathy, and renal anomalies. The proximal 1p36 genes that contribute to these defects have not been clearly delineated. The arginine-glutamic acid dipeptide (RE) repeats gene (RERE) is located in this region and encodes a nuclear receptor coregulator that plays a critical role in embryonic development as a positive regulator of retinoic acid signaling. Rere-null mice die of cardiac failure between E9.5 and E11.5. This limits their usefulness in studying the role of RERE in the latter stages of development and into adulthood. To overcome this limitation, we created an allelic series of RERE-deficient mice using an Rere-null allele, om, and a novel hypomorphic Rere allele, eyes3 (c.578T>C, p.Val193Ala), which we identified in an N-ethyl-N-nitrosourea (ENU)-based screen for autosomal recessive phenotypes. Analyses of these mice revealed microphthalmia, postnatal growth deficiency, brain hypoplasia, decreased numbers of neuronal nuclear antigen (NeuN)-positive hippocampal neurons, hearing loss, cardiovascular malformations-aortic arch anomalies, double outlet right ventricle, and transposition of the great arteries, and perimembranous ventricular septal defects-spontaneous development of cardiac fibrosis and renal agenesis. These findings suggest that RERE plays a critical role in the development and function of multiple organs including the eye, brain, inner ear, heart and kidney. It follows that haploinsufficiency of RERE may contribute-alone or in conjunction with other genetic, environmental, or stochastic factors-to the development of many of the phenotypes seen in individuals with terminal and interstitial deletions that include the proximal region of chromosome 1p36.
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