507 research outputs found
Metafrontier Functions for the Study of Inter-Regional Productivity Differences
The paper uses the concept of metafrontier functions to study regional differences in production technologies. The paper has three components. The first deals with the analytical framework necessary for the definition of metafrontier functions. The second component studies the properties of the metafrontier estimated using nonparametric data envelopment analysis (DEA). The third component focuses on the estimation of metafrontiers within the parametric framework of stochastic frontier analysis (SFA). The empirical application of the models uses cross-country agricultural sector data. The DEA and SFA metafrontiers are presented and discussed
Causal effect of plasminogen activator inhibitor type 1 on coronary heart disease
Background--Plasminogen activator inhibitor type 1 (PAI-1) plays an essential role in the fibrinolysis system and thrombosis. Population studies have reported that blood PAI-1 levels are associated with increased risk of coronary heart disease (CHD). However, it is unclear whether the association reflects a causal influence of PAI-1 on CHD risk. Methods and Results--To evaluate the association between PAI-1 and CHD, we applied a 3-step strategy. First, we investigated the observational association between PAI-1 and CHD incidence using a systematic review based on a literature search for PAI-1 and CHD studies. Second, we explored the causal association between PAI-1 and CHD using a Mendelian randomization approach using summary statistics from large genome-wide association studies. Finally, we explored the causal effect of PAI-1 on cardiovascular risk factors including metabolic and subclinical atherosclerosis measures. In the systematic meta-analysis, the highest quantile of blood PAI-1 level was associated with higher CHD risk comparing with the lowest quantile (odds ratio=2.17; 95% CI: 1.53, 3.07) in an age- and sex-adjusted model. The effect size was reduced in studies using a multivariable-adjusted model (odds ratio=1.46; 95% CI: 1.13, 1.88). The Mendelian randomization analyses suggested a causal effect of increased PAI-1 level on CHD risk (odds ratio=1.22 per unit increase of log-transformed PAI-1; 95% CI: 1.01, 1.47). In addition, we also detected a causal effect of PAI-1 on elevating blood glucose and high-density lipoprotein cholesterol. Conclusions--Our study indicates a causal effect of elevated PAI-1 level on CHD risk, which may be mediated by glucose dysfunction.</p
Expanding the role of 3-O sulfated heparan sulfate in herpes simplex virus type-1 entry
AbstractHeparan sulfate (HS) proteoglycans are commonly exploited by multiple viruses for initial attachment to host cells. Herpes simplex virus-1 (HSV-1) is unique because it can use HS for both attachment and penetration, provided specific binding sites for HSV-1 envelope glycoprotein gD are present. The interaction with gD is mediated by specific HS moieties or 3-O sulfated HS (3-OS HS), which are generated by all but one of the seven isoforms of 3-O sulfotransferases (3-OSTs). Here we demonstrate that several common experimental cell lines express unique sets of 3-OST isoforms. While the isoforms 3-OST-3, -5 and -6 were most commonly expressed, isoforms 3-OST-2 and -4 were undetectable in the cell lines examined. Since most cell lines expressed multiple 3-OST isoforms, we addressed the significance of 3-OS HS in HSV-1 entry by down-regulating 2-O-sulfation, a prerequisite for 3-OS HS formation, by knocking down 2-OST expression by RNA interference (RNAi). 2-OST knockdown was verified by reverse-transcriptase PCR and Western blot analysis, while 3-OS HS knockdown was verified by immunofluorescence. Cells showed a significant decrease in viral entry, suggesting an important role for 3-OS HS. Implicating 3-OS HS further, cells knocked down for 2-OST expression also demonstrated decreased cell–cell fusion when cocultivated with effector cells transfected with HSV-1 glycoproteins. Our findings suggest that 3-OS HS may play an important role in HSV-1 entry into many different cell lines
Improving Depression Among HIV-Infected Adults: Transporting the Effect of a Depression Treatment Intervention to Routine Care
Depression affects 20-30% of people with HIV. Randomized controlled trials (RCTs) have demonstrated the effectiveness of interventions to improve depression among HIV-infected adults, but typically have highly selected populations which may limit generalizability. Inverse probability of sampling weights (IPSW) are a recently proposed method to transport (or standardize) findings from RCTs to a specific external target population
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Atherosclerotic Biomarkers and Aortic Atherosclerosis by Cardiovascular Magnetic Resonance Imaging in the Framingham Heart Study
Background: The relations between subclinical atherosclerosis and inflammatory biomarkers have generated intense interest but their significance remains unclear. We sought to determine the association between a panel of biomarkers and subclinical aortic atherosclerosis in a community‐based cohort. Methods and Results: We evaluated 1547 participants of the Framingham Heart Study Offspring cohort who attended the 7th examination cycle and underwent both cardiovascular magnetic resonance imaging (CMR) and assays for 10 biomarkers associated with atherosclerosis: high‐sensitivity C‐reactive protein, fibrinogen, intercellular adhesion molecule‐1, interleukin‐6, interleukin‐18, lipoprotein‐associated phospholipase‐A2 activity and mass, monocyte chemoattractant protein‐1, P‐selectin, and tumor necrosis factor receptor‐2. In logistic regression analysis, we found no significant association between the biomarker panel and the presence of aortic plaque (global P=0.53). Using Tobit regression with aortic plaque as a continuous variable, we noted a modest association between biomarker panel and aortic plaque volume in age‐ and sex‐adjusted analyses (P=0.003). However, this association was attenuated after further adjustment for clinical covariates (P=0.09). Conclusions: In our community‐based cohort, we found no significant association between our multibiomarker panel and aortic plaque. Our results underscore the strengths and limitations of the use of biomarkers for the identification of subclinical atherosclerosis and the importance of traditional risk factors
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HDAC9 is implicated in atherosclerotic aortic calcification and affects vascular smooth muscle cell phenotype.
Aortic calcification is an important independent predictor of future cardiovascular events. We performed a genome-wide association meta-analysis to determine SNPs associated with the extent of abdominal aortic calcification (n = 9,417) or descending thoracic aortic calcification (n = 8,422). Two genetic loci, HDAC9 and RAP1GAP, were associated with abdominal aortic calcification at a genome-wide level (P < 5.0 × 10-8). No SNPs were associated with thoracic aortic calcification at the genome-wide threshold. Increased expression of HDAC9 in human aortic smooth muscle cells promoted calcification and reduced contractility, while inhibition of HDAC9 in human aortic smooth muscle cells inhibited calcification and enhanced cell contractility. In matrix Gla protein-deficient mice, a model of human vascular calcification, mice lacking HDAC9 had a 40% reduction in aortic calcification and improved survival. This translational genomic study identifies the first genetic risk locus associated with calcification of the abdominal aorta and describes a previously unknown role for HDAC9 in the development of vascular calcification
Pion-nucleus elastic scattering on 12C, 40Ca, 90Zr, and 208Pb at 400 and 500 MeV
Pion-nucleus elastic scattering at energies above the Delta(1232) resonance
is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The
present data provide an opportunity to study the interaction of pions with
nuclei at energies where second-order corrections to impulse approximation
calculations should be small. The results are compared with other data sets at
similar energies, and with four different first-order impulse approximation
calculations. Significant disagreement exists between the calculations and the
data from this experiment
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Biological, clinical and population relevance of 95 loci for blood lipids.
Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P < 5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD
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