519 research outputs found
Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in acute lung injury to reduce pulmonary dysfunction (HARP-2) trial : study protocol for a randomized controlled trial
Acute lung injury (ALI) is a common devastating clinical syndrome characterized by life-threatening respiratory failure requiring mechanical ventilation and multiple organ failure. There are in vitro, animal studies and pre-clinical data suggesting that statins may be beneficial in ALI. The Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial is a multicenter, prospective, randomized, allocation concealed, double-blind, placebo-controlled clinical trial which aims to test the hypothesis that treatment with simvastatin will improve clinical outcomes in patients with ALI
HIV-1 pol Diversity among Female Bar and Hotel Workers in Northern Tanzania
A national ART program was launched in Tanzania in October 2004. Due to the existence of multiple HIV-1 subtypes and recombinant viruses co-circulating in Tanzania, it is important to monitor rates of drug resistance. The present study determined the prevalence of HIV-1 drug resistance mutations among ART-naive female bar and hotel workers, a high-risk population for HIV-1 infection in Moshi, Tanzania. A partial HIV-1 pol gene was analyzed by single-genome amplification and sequencing in 45 subjects (622 pol sequences total; median number of sequences per subject, 13; IQR 5–20) in samples collected in 2005. The prevalence of HIV-1 subtypes A1, C, and D, and inter-subtype recombinant viruses, was 36%, 29%, 9% and 27%, respectively. Thirteen different recombination patterns included D/A1/D, C/A1, A1/C/A1, A1/U/A1, C/U/A1, C/A1, U/D/U, D/A1/D, A1/C, A1/C, A2/C/A2, CRF10_CD/C/CRF10_CD and CRF35_AD/A1/CRF35_AD. CRF35_AD was identified in Tanzania for the first time. All recombinant viruses in this study were unique, suggesting ongoing recombination processes among circulating HIV-1 variants. The prevalence of multiple infections in this population was 16% (n = 7). Primary HIV-1 drug resistance mutations to RT inhibitors were identified in three (7%) subjects (K65R plus Y181C; N60D; and V106M). In some subjects, polymorphisms were observed at the RT positions 41, 69, 75, 98, 101, 179, 190, and 215. Secondary mutations associated with NNRTIs were observed at the RT positions 90 (7%) and 138 (6%). In the protease gene, three subjects (7%) had M46I/L mutations. All subjects in this study had HIV-1 subtype-specific natural polymorphisms at positions 36, 69, 89 and 93 that are associated with drug resistance in HIV-1 subtype B. These results suggested that HIV-1 drug resistance mutations and natural polymorphisms existed in this population before the initiation of the national ART program. With increasing use of ARV, these results highlight the importance of drug resistance monitoring in Tanzania
Nothing Lasts Forever: Environmental Discourses on the Collapse of Past Societies
The study of the collapse of past societies raises many questions for the theory and practice of archaeology. Interest in collapse extends as well into the natural sciences and environmental and sustainability policy. Despite a range of approaches to collapse, the predominant paradigm is environmental collapse, which I argue obscures recognition of the dynamic role of social processes that lie at the heart of human communities. These environmental discourses, together with confusion over terminology and the concepts of collapse, have created widespread aporia about collapse and resulted in the creation of mixed messages about complex historical and social processes
The use of mesenchymal stem cells for cartilage repair and regeneration: a systematic review.
BACKGROUND: The management of articular cartilage defects presents many clinical challenges due to its avascular, aneural and alymphatic nature. Bone marrow stimulation techniques, such as microfracture, are the most frequently used method in clinical practice however the resulting mixed fibrocartilage tissue which is inferior to native hyaline cartilage. Other methods have shown promise but are far from perfect. There is an unmet need and growing interest in regenerative medicine and tissue engineering to improve the outcome for patients requiring cartilage repair. Many published reviews on cartilage repair only list human clinical trials, underestimating the wealth of basic sciences and animal studies that are precursors to future research. We therefore set out to perform a systematic review of the literature to assess the translation of stem cell therapy to explore what research had been carried out at each of the stages of translation from bench-top (in vitro), animal (pre-clinical) and human studies (clinical) and assemble an evidence-based cascade for the responsible introduction of stem cell therapy for cartilage defects. This review was conducted in accordance to PRISMA guidelines using CINHAL, MEDLINE, EMBASE, Scopus and Web of Knowledge databases from 1st January 1900 to 30th June 2015. In total, there were 2880 studies identified of which 252 studies were included for analysis (100 articles for in vitro studies, 111 studies for animal studies; and 31 studies for human studies). There was a huge variance in cell source in pre-clinical studies both of terms of animal used, location of harvest (fat, marrow, blood or synovium) and allogeneicity. The use of scaffolds, growth factors, number of cell passages and number of cells used was hugely heterogeneous. SHORT CONCLUSIONS: This review offers a comprehensive assessment of the evidence behind the translation of basic science to the clinical practice of cartilage repair. It has revealed a lack of connectivity between the in vitro, pre-clinical and human data and a patchwork quilt of synergistic evidence. Drivers for progress in this space are largely driven by patient demand, surgeon inquisition and a regulatory framework that is learning at the same pace as new developments take place
Hepatitis C virus infects and perturbs liver stem cells
Hepatitis C virus (HCV) is the leading cause of death from liver disease. How HCV infection causes lasting liver damage and increases cancer risk remains unclear. Here, we identify bipotent liver stem cells as novel targets for HCV infection, and their erroneous differentiation as the potential cause of impaired liver regeneration and cancer development. We show 3D organoids generated from liver stem cells from actively HCV-infected individuals carry replicating virus and maintain low-grade infection over months. Organoids can be infected with a primary HCV isolate. Virus-inclusive single-cell RNA sequencing uncovered transcriptional reprogramming in HCV+ cells supporting hepatocytic differentiation, cancer stem cell development, and viral replication while stem cell proliferation and interferon signaling are disrupted. Our data add a new pathogenesis mechanism—infection of liver stem cells—to the biology of HCV infection that may explain progressive liver damage and enhanced cancer risk through an altered stem cell state
Low Serum Glutathione Peroxidase Activity Is Associated with Increased Cardiovascular Mortality in Individuals with Low HDLc’s
Background Since oxidized LDL is thought to initiate atherosclerosis and the serum glutathione peroxidase (GPx3) reduces oxidized lipids, we investigated whether high GPx3 activity reduces cardiovascular disease (CVD) mortality. Methods We determined GPx3 in stored samples from the Minnesota Heart Survey of 130 participants who after 5 to 12 years of follow-up had died of CVD and 240 controls. Participants were 26 to 85 years old and predominantly white. In a nested case-control, study we performed logistic regressions to calculate odds ratios (OR) adjusted for age, sex, baseline year, body mass index, smoking, alcohol intake, physical activity, total and HDL cholesterols, systolic blood pressure, serum glucose and gamma glutamyltransferase (GTT) activity. The referent was the quartile with the highest GPx3 activity (quartile 4). Results OR’s for CVD mortality for increasing quartiles of GPx3 were 2.37, 2.14, 1.83 and 1.00 (P for trend 0.02). This inverse correlation was confined to those with HDLc’s below the median (P for interaction, 0.006). The OR’s for increasing quartiles of GPx3 in this group were 6.08, 5.00, 3.64 and 1.00 (P for trend, 0.002). Conclusions Individuals with both low HDLc and GPx3 activity are at markedly increased risk for death from CVD
Study protocol of psychometric properties of the Spanish translation of a competence test in evidence based practice: The Fresno test
<p>Abstract</p> <p>Background</p> <p>There are few high-quality instruments for evaluating the effectiveness of Evidence-Based Practice (EBP) curricula with objective outcomes measures. The Fresno test is an instrument that evaluates most of EBP steps with a high reliability and validity in the English original version. The present study has the aims to translate the Fresno questionnaire into Spanish and its subsequent validation to ensure the equivalence of the Spanish version against the English original.</p> <p>Methods and design</p> <p>The questionnaire will be translated with the back translation technique and tested in Primary Care Teaching Units in Catalonia (PCTU). Participants will be: (a) tutors of Family Medicine residents (expert group); (b) Family Medicine residents in their second year of the Family Medicine training program (novice group), and (c) Family Medicine physicians (intermediate group). The questionnaire will be administered before and after an educational intervention. The educational intervention will be an interactive four half-day sessions designed to develop the knowledge and skills required to EBP. Responsiveness statistics used in the analysis will be the effect size, the standardised response mean and Guyatt's method. For internal consistency reliability, two measures will be used: corrected item-total correlations and Cronbach's alpha. Inter-rater reliability will be tested using Kappa coefficient for qualitative items and intra-class correlation coefficient for quantitative items and the overall score. Construct validity, item difficulty, item discrimination and feasibility will be determined.</p> <p>Discussion</p> <p>The validation of the Fresno questionnaire into different languages will enable the expansion of the questionnaire, as well as allowing comparison between countries and the evaluation of different teaching models.</p
Human CD34+/CD90+ ASCs Are Capable of Growing as Sphere Clusters, Producing High Levels of VEGF and Forming Capillaries
Background: Human adult adipose tissue is an abundant source of mesenchymal stem cells (MSCs). Moreover, it is an easily
accessible site producing a considerable amount of stem cells.
Methodology/Principal Findings: In this study, we have selected and characterized stem cells within the stromal vascular
fraction (SVF) of human adult adipose tissue with the aim of understanding their differentiation capabilities and
performance. We have found, within the SVF, different cell populations expressing MSC markers – including CD34, CD90,
CD29, CD44, CD105, and CD117 – and endothelial-progenitor-cell markers – including CD34, CD90, CD44, and CD54.
Interestingly, CD34+/CD90+ cells formed sphere clusters, when placed in non-adherent growth conditions. Moreover, they
showed a high proliferative capability, a telomerase activity that was significantly higher than that found in differentiated
cells, and contained a fraction of cells displaying the phenotype of a side population. When cultured in adipogenic medium,
CD34+/CD90+ quickly differentiated into adipocytes. In addition, they differentiated into endothelial cells (CD31+/VEGF+/Flk-
1+) and, when placed in methylcellulose, were capable of forming capillary-like structures producing a high level of VEGF, as
substantiated with ELISA tests.
Conclusions/Significance: Our results demonstrate, for the first time, that CD34+/CD90+ cells of human adipose tissue are
capable of forming sphere clusters, when grown in free-floating conditions, and differentiate in endothelial cells that form
capillary-like structures in methylcellulose. These cells might be suitable for tissue reconstruction in regenerative medicine,
especially when patients need treatments for vascular disease
Adipose-derived mesenchymal stem cells from the sand rat: transforming growth factor beta and 3D co-culture with human disc cells stimulate proteoglycan and collagen type I rich extracellular matrix
Over-expression of lysophosphatidic acid receptor-2 in human invasive ductal carcinoma
INTRODUCTION: Lysophosphatidic acid (LPA) is a bioactive phospholipid with diverse effects on various cells. It interacts with at least three G-protein-coupled transmembrane receptors, namely LPA1, LPA2 and LPA3, whose expression in various tumours has not been fully characterized. In the present study we characterized the expression profile of LPA receptors in human breast cancer tissue and assessed the possible roles of each receptor. METHODS: The relative expression levels of each receptor's mRNA against β-actin mRNA was examined in surgically resected invasive ductal carcinomas and normal gland tissue using real-time RT-PCR. LPA2 expression was also examined immunohistochemically using a rat anti-LPA2 monoclonal antibody. RESULTS: In 25 cases normal and cancer tissue contained LPA1 mRNA at similar levels, whereas the expression level of LPA2 mRNA was significantly increased in cancer tissue as compared with its normal counterpart (3479.0 ± 426.6 versus 1287.3 ± 466.8; P < 0.05). LPA3 was weakly expressed in both cancer and normal gland tissue. In 48 (57%) out of 84 cases, enhanced expression of LPA2 protein was confirmed in carcinoma cells as compared with normal mammary epithelium by immunohistochemistry. Over-expression of LPA2 was detected in 17 (45%) out of 38 premenopausal women, as compared with 31 (67%) out of 46 postmenopausal women, and the difference was statistically significant (P < 0.05). CONCLUSION: These findings suggest that upregulation of LPA2 may play a role in carcinogenesis, particularly in postmenopausal breast cancer
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