2,362 research outputs found

    Bradykinin Type 2 Receptor BE1 Genotype Influences Bradykinin-dependent Vasodilation During Angiotensin-converting Enzyme Inhibition

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    To test the hypothesis that the bradykinin receptor 2 (BDKRB2) BE1+9/-9 polymorphism affects vascular responses to bradykinin, we measured the effect of intra-arterial bradykinin on forearm blood flow and tissue-type plasminogen activator (t-PA) release in 89 normotensive, nonsmoking, white American subjects in whom degradation of bradykinin was blocked by enalaprilat. BE1 genotype frequencies were +9/+9:+9/-9:-9/-9=19:42:28. BE1 genotype was associated with systolic blood pressure (121.4+/-2.8, 113.8+/-1.8, and 110.6+/-1.8 mm Hg in +9/+9, +9/-9, and -9/-9 groups, respectively; P=0.007). In the absence of enalaprilat, bradykinin-stimulated forearm blood flow, forearm vascular resistance, and net t-PA release were similar among genotype groups. Enalaprilat increased basal forearm blood flow (P=0.002) and decreased basal forearm vascular resistance (P=0.01) without affecting blood pressure. Enalaprilat enhanced the effect of bradykinin on forearm blood flow, forearm vascular resistance, and t-PA release (all P\u3c0.001). During enalaprilat, forearm blood flow was significantly lower and forearm vascular resistance was higher in response to bradykinin in the +9/+9 compared with +9/-9 and -9/-9 genotype groups (P=0.04 for both). t-PA release tended to be decreased in response to bradykinin in the +9/+9 group (P=0.08). When analyzed separately by gender, BE1 genotype was associated with bradykinin-stimulated t-PA release in angiotensin-converting enzyme inhibitor-treated men but not women (P=0.02 and P=0.77, respectively), after controlling for body mass index. There was no effect of BE1 genotype on responses to the bradykinin type 2 receptor-independent vasodilator methacholine during enalaprilat. In conclusion, the BDKRB2 BE1 polymorphism influences bradykinin type 2 receptor-mediated vasodilation during angiotensin-converting enzyme inhibition

    The Absolute Magnitudes of Type Ia Supernovae in the Ultraviolet

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    We examine the absolute magnitudes and light-curve shapes of 14 nearby(redshift z = 0.004--0.027) Type Ia supernovae (SNe~Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way (MW) extinction law and one for the Large Magellanic Cloud that has been modified by circumstellar scattering. We find very different behavior in the near-UV filters (uvw1_rc covering ~2600-3300 A after removing optical light, and u ~3000--4000 A) compared to a mid-UV filter (uvm2 ~2000-2400 A). The uvw1_rc-b colors show a scatter of ~0.3 mag while uvm2-b scatters by nearly 0.9 mag. Similarly, while the scatter in colors between neighboring filters is small in the optical and somewhat larger in the near-UV, the large scatter in the uvm2-uvw1 colors implies significantly larger spectral variability below 2600 A. We find that in the near-UV the absolute magnitudes at peak brightness of normal SNe Ia in our sample are correlated with the optical decay rate with a scatter of 0.4 mag, comparable to that found for the optical in our sample. However, in the mid-UV the scatter is larger, ~1 mag, possibly indicating differences in metallicity. We find no strong correlation between either the UV light-curve shapes or the UV colors and the UV absolute magnitudes. With larger samples, the UV luminosity might be useful as an additional constraint to help determine distance, extinction, and metallicity in order to improve the utility of SNe Ia as standardized candles.Comment: 59 pages, accepted for publication in Ap

    SN 2008inā€”Bridging the Gap between Normal and Faint Supernovae of Type IIP

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    We present optical photometric and low-resolution spectroscopic observations of the Type II plateau supernova (SN) 2008in, which occurred in the outskirts of the nearly face-on spiral galaxy M61. Photometric data in the X-ray, ultraviolet, and near-infrared bands have been used to characterize this event. The SN field was imaged with the ROTSE-IIIb optical telescope about seven days before the explosion. This allowed us to constrain the epoch of the shock breakout to JD = 2454825.6. The duration of the plateau phase, as derived from the photometric monitoring, was ~98 days. The spectra of SN 2008in show a striking resemblance to those of the archetypal low-luminosity IIP SNe 1997D and 1999br. A comparison of ejecta kinematics of SN 2008in with the hydrodynamical simulations of Type IIP SNe by Dessart et al. indicates that it is a less energetic event (~5 Ɨ 10^(50) erg). However, the light curve indicates that the production of radioactive ^(56)Ni is significantly higher than that in the low-luminosity SNe. Adopting an interstellar absorption along the SN direction of AV ~ 0.3 mag and a distance of 13.2 Mpc, we estimated a synthesized ^(56)Ni mass of ~0.015 M_ā˜‰. Employing semi-analytical formulae derived by Litvinova and Nadezhin, we derived a pre-SN radius of ~126 R_ā˜‰, an explosion energy of ~5.4 Ɨ 10^(50) erg, and a total ejected mass of ~16.7 M_ā˜‰. The latter indicates that the zero-age main-sequence mass of the progenitor did not exceed 20 M_ā˜‰. Considering the above properties of SN 2008in and its occurrence in a region of sub-solar metallicity ([O/H] ~ 8.44 dex), it is unlikely that fall-back of the ejecta onto a newly formed black hole occurred in SN 2008in. We therefore favor a low-energy explosion scenario of a relatively compact, moderate-mass progenitor star that generates a neutron star

    Ecological and evolutionary drivers of hemoplasma infection and bacterial genotype sharing in a Neotropical bat community

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    Most emerging pathogens can infect multiple species, underlining the importance of understanding the ecological and evolutionary factors that allow some hosts to harbour greater infection prevalence and share pathogens with other species. However, our understanding of pathogen jumps is based primarily around viruses, despite bacteria accounting for the greatest proportion of zoonoses. Because bacterial pathogens in bats (order Chiroptera) can have conservation and human health consequences, studies that examine the ecological and evolutionary drivers of bacterial prevalence and barriers to pathogen sharing are crucially needed. Here were studied haemotropic Mycoplasma spp. (i.e., haemoplasmas) across a speciesĆ¢ā‚¬rich bat community in Belize over two years. Across 469 bats spanning 33 species, half of individuals and twoĆ¢ā‚¬thirds of species were haemoplasma positive. Infection prevalence was higher for males and for species with larger body mass and colony sizes. Haemoplasmas displayed high genetic diversity (21 novel genotypes) and strong host specificity. Evolutionary patterns supported codivergence of bats and bacterial genotypes alongside phylogenetically constrained host shifts. Bat species centrality to the network of shared haemoplasma genotypes was phylogenetically clustered and unrelated to prevalence, further suggesting rareĆ¢ā‚¬ā€but detectableĆ¢ā‚¬ā€bacterial sharing between species. Our study highlights the importance of using fine phylogenetic scales when assessing host specificity and suggests phylogenetic similarity may play a key role in host shifts not only for viruses but also for bacteria. Such work more broadly contributes to increasing efforts to understand crossĆ¢ā‚¬species transmission and the epidemiological consequences of bacterial pathogens

    Advanced EFL learners' beliefs about language learning and teaching: a comparison between grammar, pronunciation, and vocabulary

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    This paper reports on the results of a study exploring learnersā€™ beliefs on the learning and teaching of English grammar, pronunciation and vocabulary at tertiary level. While the importance of learnersā€™ beliefs on the acquisition process is generally recognized, few studies have focussed on and compared learnersā€™ views on different components of the language system. A questionnaire containing semantic scale and Likert scale items probing learnersā€™ views on grammar, pronunciation and vocabulary was designed and completed by 117 native speakers of Dutch in Flanders, who were studying English at university. The analysis of the responses revealed that (i) vocabulary was considered to be different from grammar and pronunciation, both in the extent to which an incorrect use could lead to communication breakdown and with respect to the learnersā€™ language learning strategies, (ii) learners believed in the feasibility of achieving a native-like proficiency in all three components, and (iii) in-class grammar, pronunciation and vocabulary exercises were considered to be useful, even at tertiary level. The results are discussed in light of pedagogical approaches to language teaching

    Higher urinary cortisol levels associate with increased cardiovascular risk

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    There are conflicting data on whether variations of physiologic cortisol levels associated with cardiovascular risk. We hypothesize that prior discordant findings are related to problems associated with varying sample size, techniques for assessing cardiovascular risk and failure to adequately account for environmental factor s. To address these issues, we utilized a large sample size, selected the Framingham risk score to compute cardiovascular risk and performed the study in a highly controlled setting. We had two main objectives: determine whether higher, yet physiologic, cortisol levels associated with increased cardiovascular risk and determine whether caveol in-1 (rs926198) risk allele carriers associated with increased cardiovascular risk. This was a cross-sectional study of 574 non-diabetic individuals who completed a common protocol. Data collection included fasting blood samples, blood pressure measurements and a 24-h urine-free cortisol collection. Five hundred seventeen of these participants also completed caveolin-1 genotyping. Subjects were classified as belonging to either the low-mode or high-mode urine-free cortisol groups, based on the bimodal distribution of urine-free cortisol. In multivariate analysis, Framingham risk score was statistically higher in the high-mode cortisol group (10.22 (mean) Ā± 0.43 (s.e.m.)) compared to the low-mode cortisol group (7.73 Ā± 0.34), P < 0.001. Framingham risk score was also statistically higher in n the caveolin-1 risk allele carriers (8.91 Ā± 0.37) compared to caveolin-1 non-risk allele carriers (7.59 Ā± 0.48), P = 0.034. Overall, the estimated effect on Framingham risk score of carrying the caveolin-1 risk allele was 1.33 Ā± 0.61, P = 0.029. Both urinary cortisol and caveolin-1 risk allele status are independent predictors of Framingham risk score

    Rapid Generation of MicroRNA Sponges for MicroRNA Inhibition

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    MicroRNA (miRNA) sponges are transcripts with repeated miRNA antisense sequences that can sequester miRNAs from endogenous targets. MiRNA sponges are valuable tools for miRNA loss-of-function studies both in vitro and in vivo. We developed a fast and flexible method to generate miRNA sponges and tested their efficiency in various assays. Using a single directional ligation reaction we generated sponges with 10 or more miRNA binding sites. Luciferase and AGO2-immuno precipitation (IP) assays confirmed effective binding of the miRNAs to the sponges. Using a GFP competition assay we showed that miR-19 sponges with central mismatches in the miRNA binding sites are efficient miRNA inhibitors while sponges with perfect antisense binding sites are not. Quantification of miRNA sponge levels suggests that this is at least in part due to degradation of the perfect antisense sponge transcripts. Finally, we provide evidence that combined inhibition of miRNAs of the miR-17āˆ¼92 cluster results in a more effective growth inhibition as compared to inhibition of individual miRNAs. In conclusion, we describe and validate a method to rapidly generate miRNA sponges for miRNA loss-of-function studies

    Exome Sequencing Reveals Common and Rare Variants in F5 Associated With ACE Inhibitor and Angiotensin Receptor Blockerā€“Induced Angioedema

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    Angioedema occurring in the head and neck region is a rare and sometimes lifeā€threatening adverse reaction to angiotensinā€converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). Few studies have investigated the association of common variants with this extreme reaction, but none have explored the combined influence of rare variants yet. Adjudicated cases of ACEIā€induced angioedema (ACEIā€AE) or ARBā€induced angioedema (ARBā€AE) and controls were recruited at five different centers. Sequencing of 1,066 samples (408 ACEIā€AE, ARBā€AE, and 658 controls) was performed using exomeā€enriched sequence data. A common variant of the F5 gene that causes an increase in blood clotting (rs6025, p.Arg506Gln, also called factor V Leiden), was significantly associated with both ACEIā€AE and ARBā€AE (odds ratio: 2.85, 95% confidence interval (CI), 1.89ā€“4.25). A burden test analysis of five rare missense variants in F5 was also found to be associated with ACEIā€AE or ARBā€AE, P = 2.09 Ɨ 10āˆ’3. A combined gene risk score of these variants, and the common variants rs6025 and rs6020, showed that individuals carrying at least one variant had 2.21 (95% CI, 1.49ā€“3.27, P = 6.30 Ɨ 10āˆ’9) times the odds of having ACEIā€AE or ARBā€AE. The increased risk due to the common Leiden allele was confirmed in a genomeā€wide association study from the United States. A high risk of angioedema was also observed for the rs6020 variant that is the main coagulation defectā€causing variant in black African and Asian populations. We found that deleterious missense variants in F5 are associated with an increased risk of ACEIā€AE or ARBā€AE
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