Oxidative Damage to DNA and Lipids as Biomarkers of Exposure to Air Pollution

Ba c k g r o u n d: Air pollution is thought to exert health effects through oxidative stress, which causes damage to DNA and lipids. Obj e c t i v e: We determined whether levels of oxidatively damaged DNA and lipid peroxidation products in cells or bodily fluids from humans are useful biomarkers of biologically effective dose in studies of the health effects of exposure to particulate matter (PM) from combustion processes. Data s o u r c e s: We identified publications that reported estimated associations between environmental exposure to PM and oxidative damage to DNA and lipids in PubMed and EMBASE. We also identified publications from reference lists and articles cited in the Web of Science. Data extraction: For each study, we obtained information on the estimated effect size to calculate the standardized mean difference (unitless) and determined the potential for errors in exposure assessment and analysis of each of the biomarkers, for total and stratified formal meta-analyses. Data synthesis: In the meta-analysis, the standardized mean differences (95 % confidence interval) between exposed and unexposed subjects for oxidized DNA and lipids were 0.53 (0.29–0.76) and 0.73 (0.18–1.28) in blood and 0.52 (0.22–0.82) and 0.49 (0.01–0.97) in urine, respectively. The standardized mean difference for oxidized lipids was 0.64 (0.07–1.21) in the airways. Restricting analyses to studies unlikely to have substantial biomarker or exposure measurement error, studies likely to have biomarker and/or exposure error, or studies likely to have both sources of error resulted in standardized mean differences of 0.55 (0.19–0.90), 0.66 (0.37–0.95), and 0.65 (0.34–0.96), respectively. Co n c l u s i o n s: Exposure to combustion particles is consistenly associated with oxidatively damaged DNA and lipids in humans, suggesting that it is possible to use these measurements as biomarkers of biologically effective dose. Key w o r d s: biomarker, DNA damage, lipid peroxidation products, oxidative stress, particulate matter. Environ Health Perspect 118:1126–1136 (2010). doi:10.1289/ehp.0901725 [Onlin

Single photon multiclock lock-in detection by picosecond timestamping

Extracting signals at low single-photon count rates from large backgrounds is a challenge in many optical experiments and technologies. Here, we demonstrate a single-photon lock-in detection scheme based on continuous photon timestamping to improve the SNR by more than two orders of magnitude. Through time-resolving the signal modulation induced by periodic perturbations, 98% of dark counts are filtered out and the &lt; 1 c o u n t / s contributions from several different nonlinear processes identified. As a proof-of-concept, coherent anti-Stokes Raman measurements are used to determine the vibrational lifetime of few molecules in a plasmonic nanocavity. This detection scheme can be applied to all single-photon counting experiments with any number of simultaneous modulation frequencies, greatly increasing SNR and resolving physical processes with picosecond time resolution while keeping the photon dosage small. The open instrumentation package provided here enables low-cost implementation.</jats:p

Complex regional pain syndrome type I: efficacy of stellate ganglion blockade

PubMed ID: 19888550Background: This study was performed to evaluate the treatment of complex regional pain syndrome (CRPS) type I with stellate ganglion blockade. Materials and methods: We performed three blockades at weekly intervals in 22 patients with CRPS type I in one hand. The patients were divided into two groups depending on the time between symptom onset and treatment initiation. Group 1and 2 patients had short and long symptom-onset-to-treatment intervals, respectively. Pain intensity, using a visual analog score (VAS), and range of motion (ROM) for the wrist joint were assessed before and 2 weeks after treatment and were compared using nonparametric statistical analysis. Results: Treatment produced a statistically significant difference in wrist ROM for all patients (P < 0.001). VAS values showed an overall decrease from 8 ± 1 to 1 ± 1 following treatment, and there was a significant difference in VAS value between groups 1 and 2 (P < 0.05). Conclusions: We concluded that stellate ganglion blockade successfully decreased VAS and increased ROM of wrist joints in patients with CRPS type I. Further, the duration between symptom onset and therapy initiation was a major factor affecting blockade success. © 2009 Springer-Verlag

Identification of a tyrosine residue responsible for N-acetylimidazole-induced increase of activity of ecto-nucleoside triphosphate diphosphohydrolase 3

Chemical modification in combination with site-directed mutagenesis was used to identify a tyrosine residue responsible for the increase in ecto-nucleoside triphosphate diphosphohydrolase 3 (NTPDase3) nucleotidase activity after acetylation with a tyrosine-selective reagent, N-acetylimidazole. The NTPDase3 ATPase activity is increased more than the ADPase activity by this reagent. Several fairly well conserved tyrosine residues (252, 255, and 262) that are located in or very near apyrase conserved region 4a (ACR4a) were mutated. These mutants were all active, but mutation of tyrosine 252 to either alanine or phenylalanine eliminated the activity increase observed after N-acetylimidazole treatment of the wild-type enzyme. This suggests that the acetylation of tyrosine 252 is responsible for the increased activity. Stabilization of quaternary structure has resulted in increased enzyme activities for the NTPDases. However, mutation of these three tyrosine residues did not result in global changes of tertiary or quaternary structure, as measured by Cibacron blue binding, chemical cross linking, and native gel electrophoretic analysis. Nevertheless, disruption of the oligomeric structure with the detergent Triton X-100 abolished the increase in activity induced by this reagent. In addition, mutations that abolished the N-acetylimidazole effect also attenuated the increases of enzyme activity observed after lectin and chemical cross-linking treatments, which were previously attributed to stabilization of the quaternary structure. Thus, we speculate that the acetylation of tyrosine 252 might induce a subtle conformational change in NTPDase3, resulting in the observed increase in activity

Bargaining with Optimism

Excessive optimism is a prominent explanation for bargaining delays. Recent results demonstrate that optimism plays a subtle role in bargaining, and its careful analysis may shed valuable insights into negotiation behavior. This article reviews some of these results, focusing on the following findings. First, when there is a nearby deadline, optimistic players delay the agreement to the last period before the deadline, replicating a broad empirical regularity known as the deadline effect. Second, there cannot be a substantial delay under persistent optimism; i.e., excessive optimism alone cannot explain delays. Third, when optimistic players are expected to learn during the negotiation, they delay the agreement in order to persuade their opponents. The delays in these results can be quite costly, Pareto inefficient, and common knowledge at the beginning of the game

Organism-sediment interactions govern post-hypoxia recovery of ecosystem functioning

Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning.

Lambda and Antilambda polarization from deep inelastic muon scattering

We report results of the first measurements of Lambda and Antilambda polarization produced in deep inelastic polarized muon scattering on the nucleon. The results are consistent with an expected trend towards positive polarization with increasing x_F. The polarizations of Lambda and Antilambda appear to have opposite signs. A large negative polarization for Lambda at low positive x_F is observed and is not explained by existing models.A possible interpretation is presented.Comment: 9 pages, 2 figure

The AFLOW Fleet for Materials Discovery

The traditional paradigm for materials discovery has been recently expanded to incorporate substantial data driven research. With the intent to accelerate the development and the deployment of new technologies, the AFLOW Fleet for computational materials design automates high-throughput first principles calculations, and provides tools for data verification and dissemination for a broad community of users. AFLOW incorporates different computational modules to robustly determine thermodynamic stability, electronic band structures, vibrational dispersions, thermo-mechanical properties and more. The AFLOW data repository is publicly accessible online at aflow.org, with more than 1.7 million materials entries and a panoply of queryable computed properties. Tools to programmatically search and process the data, as well as to perform online machine learning predictions, are also available.Comment: 14 pages, 8 figure

Determinants of racial/ethnic differences in blood pressure management among hypertensive patients

BACKGROUND: Prior literature has shown that racial/ethnic minorities with hypertension may receive less aggressive treatment for their high blood pressure. However, to date there are few data available regarding the confounders of racial/ethnic disparities in the intensity of hypertension treatment. METHODS: We reviewed the medical records of 1,205 patients who had a minimum of two hypertension-related outpatient visits to 12 general internal medicine clinics during 7/1/01-6/30/02. Using logistic regression, we determined the odds of having therapy intensified by patient race/ethnicity after adjustment for clinical characteristics. RESULTS: Blacks (81.9%) and Whites (80.3%) were more likely than Latinos (71.5%) to have therapy intensified (P = 0.03). After adjustment for racial differences in the number of outpatient visits and presence of diabetes, there were no racial differences in rates of intensification. CONCLUSION: We found that racial/ethnic differences in therapy intensification were largely accounted for by differences in frequency of clinic visits and in the prevalence of diabetes. Given the higher rates of diabetes and hypertension related mortality among Hispanics in the U.S., future interventions to reduce disparities in cardiovascular outcomes should increase physician awareness of the need to intensify drug therapy more agressively in patients without waiting for multiple clinic visits, and should remind providers to treat hypertension more aggressively among diabetic patients