287 research outputs found
Engine-Operating Load Influences Diesel Exhaust Composition and Cardiopulmonary and Immune Responses
Background: The composition of diesel engine exhaust (DEE) varies by engine type and condition, fuel, engine operation, and exhaust after treatment such as particle traps. DEE has been shown to increase inflammation, susceptibility to infection, and cardiovascular responses in experimentally exposed rodents and humans. Engines used in these studies have been operated at idle, at different steady-state loads, or on variable-load cycles, but exposures are often reported only as the mass concentration of particulate matter (PM), and the effects of different engine loads and the resulting differences in DEE composition are unknown
In vivo and in vitro expression of steroid-converting enzymes in human breast tumours: associations with interleukin-6
Enzymes modulating local steroid availability play an important role in the progression of human breast cancer. These include isoforms of 17β-hydroxysteroid dehydrogenase (17-HSD), aromatase and steroid sulphatase (STS). The aim of this study was to investigate the expression, by reverse transcription polymerase chain reaction, of 17-HSD types I–IV, aromatase and steroid STS in a series of 51 human breast tumour biopsies and 22 primary cultures of epithelial and stromal cells derived from these tumours, giving a profile of the steroid-regulating network for individual tumours. Correlations between enzyme expression profiles and expression of the interleukin (IL)-6 gene were also sought. All except one tumour expressed at least one isoform of 17-HSD, either alone or in combination with aromatase and STS. Expression of 17-HSD isoforms I–IV were observed in nine tumours. Of the 15 tumours which expressed three isoforms, a combination of 17-HSD II, III and IV was most common (6/15 samples). The majority of tumours (n = 17) expressed two isoforms of 17-HSD with combinations of 17-HSD II and IV predominant (7/17 samples). Eight tumours expressed a single isoform and of these, 17-HSD I was in the majority (5/8 samples). In primary epithelial cultures, enzyme expression was ranked: HSD I (86%) > STS (77%) > HSD II (59%) > HSD IV (50%) = aromatase (50%) > HSD III (32%). Incidence of enzyme expression was generally reduced in stromal cultures which were ranked: HSD I (68%) > STS (67%) > aromatase (48%) > HSD II (43%) > HSD IV (28%) > HSD III (19%). Expression of IL-6 was associated with tumours that expressed ≥ 3 steroid-converting enzymes. These tumours were of higher grade and tended to come from patients with family history of breast cancer. In conclusion, we propose that these enzymes work in tandem with cytokines thereby providing sufficient quantities of bioactive oestrogen from less active precursors which stimulates tumour growth. © 1999 Cancer Research Campaig
Impairment experiences, identity and attitudes towards genetic screening : the views of people with Spinal Muscular Atrophy
Developments in genetics are rapidly changing the capacity and scope of screening practices. However, people with genetic conditions have been under-represented in the literature exploring their implications. This mixed methods study explores the attitudes of people with Spinal Muscular Atrophy (SMA) towards three different population-level genetic screening programmes for SMA: pre-conception, prenatal and newborn. Drawing on qualitative interviews (n= 15) and a survey (n=82), this study demonstrates that more severely affected individuals with early-onset symptoms (Type II SMA), are less likely to support screening and more likely to view SMA positively than those with milder, later onset and/or fluctuating symptoms (Types III/ IV SMA). Indeed, this clinically milder group were more likely to support all forms of screening and view SMA negatively. This paper highlights that screening is a complex issue for people with genetic conditions, and the nature of impairment experiences plays a critical role in shaping attitudes
Differences in carotid arterial morphology and composition between individuals with and without obstructive coronary artery disease: A cardiovascular magnetic resonance study
Objective: We sought to determine differences with cardiovascular magnetic resonance (CMR) in the morphology and composition of the carotid arteries between individuals with angiographically-defined obstructive coronary artery disease (CAD, = 50% stenosis, cases) and
those with angiographically normal coronaries (no lumen irregularities, controls).
Methods and results: 191 participants (50.3% female; 50.8% CAD cases) were imaged with a multi-sequence, carotid CMR protocol at 1.5T. For each segment of the carotid, lumen area, wall area, total vessel area (lumen area + wall area), mean wall thickness and the presence or absence
of calcification and lipid-rich necrotic core were recorded bilaterally. In male CAD cases compared to male controls, the distal bulb had a significantly smaller lumen area (60.0 [plus or minus] 3.1 vs. 79.7 [plus or minus] 3.2 mm[super]2, p less than 0.001) and total vessel area (99.6 [plus or minus] 4.0 vs. 119.8 [plus or minus] 4.1 mm[super]2; p less than 0.001), and larger mean wall thickness (1.25 [plus or minus] 0.03 vs. 1.11 [plus or minus] 0.03 mm; p = 0.002). Similarly, the internal carotid had a smaller lumen area (37.5 [plus or minus] 1.8 vs. 44.6 [plus or minus] 1.8 mm[super]2; p = 0.006) and smaller total vessel area (64.0 [plus or minus] 2.3 vs. 70.9 [plus or minus] 2.4 mm[super]2; p = 0.04). These metrics were not significantly different between female
groups in the distal bulb and internal carotid or for either gender in the common carotid. Male CAD cases had an increased prevalence of lipid-rich necrotic core (49.0% vs. 19.6%; p = 0.003), while calcification was more prevalent in both male (46.9% vs. 17.4%; p = 0.002) and female (33.3% vs. 14.6%; p = 0.031) CAD cases compared to controls.
Conclusion: Males with obstructive CAD compared to male controls had carotid bulbs and internal carotid arteries with smaller total vessel and lumen areas, and an increased prevalence of lipid-rich necrotic core. Carotid calcification was related to CAD status in both males and females. Carotid CMR identifies distinct morphological and compositional differences in the carotid arteries
between individuals with and without angiographically-defined obstructive CAD.Carotid Atherosclerosis (MRI) Progression Study (CAMPS, HL076378) and Cardiovascular Research Training Program (T-32, HL07838); and the General Clinical Research Center at the Wake Forest University School of Medicine (M01 RR-07122)
Prolyl Hydroxylase Substrate Adenylosuccinate Lyase Is An Oncogenic Driver In Triple Negative Breast Cancer
Exploring Metabolic Pathway Reconstruction and Genome-Wide Expression Profiling in Lactobacillus reuteri to Define Functional Probiotic Features
The genomes of four Lactobacillus reuteri strains isolated from human breast milk and the gastrointestinal tract have been recently sequenced as part of the Human Microbiome Project. Preliminary genome comparisons suggested that these strains belong to two different clades, previously shown to differ with respect to antimicrobial production, biofilm formation, and immunomodulation. To explain possible mechanisms of survival in the host and probiosis, we completed a detailed genomic comparison of two breast milk–derived isolates representative of each group: an established probiotic strain (L. reuteri ATCC 55730) and a strain with promising probiotic features (L. reuteri ATCC PTA 6475). Transcriptomes of L. reuteri strains in different growth phases were monitored using strain-specific microarrays, and compared using a pan-metabolic model representing all known metabolic reactions present in these strains. Both strains contained candidate genes involved in the survival and persistence in the gut such as mucus-binding proteins and enzymes scavenging reactive oxygen species. A large operon predicted to encode the synthesis of an exopolysaccharide was identified in strain 55730. Both strains were predicted to produce health-promoting factors, including antimicrobial agents and vitamins (folate, vitamin B12). Additionally, a complete pathway for thiamine biosynthesis was predicted in strain 55730 for the first time in this species. Candidate genes responsible for immunomodulatory properties of each strain were identified by transcriptomic comparisons. The production of bioactive metabolites by human-derived probiotics may be predicted using metabolic modeling and transcriptomics. Such strategies may facilitate selection and optimization of probiotics for health promotion, disease prevention and amelioration
Assessing the Value of DNA Barcodes and Other Priority Gene Regions for Molecular Phylogenetics of Lepidoptera
BACKGROUND: Despite apparently abundant amounts of observable variation and species diversity, the order Lepidoptera exhibits a morphological homogeneity that has provided only a limited number of taxonomic characters and led to widespread use of nucleotides for inferring relationships. This study aims to characterize and develop methods to quantify the value of priority gene regions designated for Lepidoptera molecular systematics. In particular, I assess how the DNA barcode segment of the mitochondrial COI gene performs across a broad temporal range given its number one position of priority, most sequenced status, and the conflicting opinions on its phylogenetic performance. METHODOLOGY/PRINCIPAL FINDINGS: Gene regions commonly sequenced for lepidoptera phylogenetics were scored using multiple measures across three categories: practicality, which includes universality of primers and sequence quality; phylogenetic utility; and phylogenetic signal. I found that alternative measures within a category often appeared correlated, but high scores in one category did not necessarily translate into high scores in another. The DNA barcode was easier to sequence than other genes, and had high scores for utility but low signal above the genus level. CONCLUSIONS/SIGNIFICANCE: Given limited financial resources and time constraints, careful selection of gene regions for molecular phylogenetics is crucial to avoid wasted effort producing partially informative data. This study introduces an approach to assessing the value of gene regions prior to the initiation of new studies and presents empirical results to help guide future selections
Mapping Oil and Gas Development Potential in the US Intermountain West and Estimating Impacts to Species
Many studies have quantified the indirect effect of hydrocarbon-based economies on climate change and biodiversity, concluding that a significant proportion of species will be threatened with extinction. However, few studies have measured the direct effect of new energy production infrastructure on species persistence. in the western US and translate the build-out scenarios into estimated impacts on sage-grouse. We project that future oil and gas development will cause a 7–19 percent decline from 2007 sage-grouse lek population counts and impact 3.7 million ha of sagebrush shrublands and 1.1 million ha of grasslands in the study area.Maps of where oil and gas development is anticipated in the US Intermountain West can be used by decision-makers intent on minimizing impacts to sage-grouse. This analysis also provides a general framework for using predictive models and build-out scenarios to anticipate impacts to species. These predictive models and build-out scenarios allow tradeoffs to be considered between species conservation and energy development prior to implementation
On ethically solvent leaders : the roles of pride and moral identity in predicting leader ethical behavior.
The popular media has repeatedly pointed to pride as one of the key factors motivating leaders to behave unethically. However, given the devastating consequences that leader unethical behavior may have, a more scientific account of the role of pride is warranted. The present study differentiates between authentic and hubristic pride and assesses its impact on leader ethical behavior, while taking into consideration the extent to which leaders find it important to their self-concept to be a moral person. In two experiments we found that with higher levels of moral identity, authentically proud leaders are more likely to engage in ethical behavior than hubristically proud leaders, and that this effect is mediated by leaders’ motivation to act selflessly. A field survey among organizational leaders corroborated that moral identity may bring the positive effect of authentic pride and the negative effect of hubristic pride on leader ethical behavior to the forefront
Biotransformation of lanthanum by Aspergillus niger
Lanthanum is an important rare earth element and has many applications in modern electronics and catalyst manufacturing. However, there exist several obstacles in the recovery and cycling of this element due to a low average grade in exploitable deposits and low recovery rates by energy-intensive extraction procedures. In this work, a novel method to transform and recover La has been proposed using the geoactive properties of Aspergillus niger. La-containing crystals were formed and collected after A. niger was grown on Czapek-Dox agar medium amended with LaCl 3. Energy-dispersive X-ray analysis (EDXA) showed the crystals contained C, O, and La; scanning electron microscopy revealed that the crystals were of a tabular structure with terraced surfaces. X-ray diffraction identified the mineral phase of the sample as La 2(C 2O 4) 3·10H 2O. Thermogravimetric analysis transformed the oxalate crystals into La 2O 3 with the kinetics of thermal decomposition corresponding well with theoretical calculations. Geochemical modelling further confirmed that the crystals were lanthanum decahydrate and identified optimal conditions for their precipitation. To quantify crystal production, biomass-free fungal culture supernatants were used to precipitate La. The results showed that the precipitated lanthanum decahydrate achieved optimal yields when the concentration of La was above 15 mM and that 100% La was removed from the system at 5 mM La. Our findings provide a new aspect in the biotransformation and biorecovery of rare earth elements from solution using biomass-free fungal culture systems. </p
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