1,307 research outputs found
Vaporized Nicotine Inhalation Increases Arterial Pressure in both Supine and 70o Head-up Positions
ABSTRACT
Electronic cigarettes (e-cigs) are popular with smokers looking for a healthier alternative to tobacco cigarettes. E-cigs utilize a battery, activated on inhalation, to heat propylene glycol-suspended nicotine which is inhaled as vapor, and which does not include harmful poisons found in conventional cigarettes. Although the health claims of e-cigs continue to be debated, the effects of nicotine delivered as vapor on the cardiovascular system have not been studied. Because nicotine is a sympathomemetic agent, we tested the hypothesis that e-cigs would increase arterial pressure and protect against challenges associated with upright posture. Ten non-smoking subjects (5 male) participated in two experimental trials, separated by one week (randomized). Seated blood pressures were taken after a 10 min quiet rest period, and then subjects either inhaled (once every 30 s for 10 min) on an e-cig with a placebo cartridge (0 mg nicotine) or an active cartridge (18 mg nicotine). After an additional 10 min quiet seated rest, we measured blood pressure again, and then subjects provided a urine sample for analysis of cotinine (a nicotine biomarker). We recorded ECG and finger photoplethysmographic arterial pressure. Subjects breathed to a metronome set at 15 breaths/min for 5 min supine, 5 min head-up (70o), and 5 min supine (recovery). Cotinine readings failed to register the presence of nicotine in urine, but a majority of subjects experienced dizziness and nausea after the active, but not the placebo cartridge. Seated arterial pressures were similar after the placebo cartridge (p â„ .05), but increased from 112 ± 3/62 ± 2 mmHg to 115 ± 3/67 ± 3 after the nicotine cartridge (p â€. 05). Systolic and diastolic pressures were higher (all p †.05) after the nicotine trial compared to placebo for supine (115 ± 3/69 ± 2 vs. 106 ± 4/62 ± 2 mmHg), tilt (105 ± 4/66 ± 3 vs. 93 ± 4/60 ± 3 mmHg), and recovery (117 ± 5/72 ± 2 vs. 106 ± 4/64 ± 3 mmHg). No subject experienced presyncope during tilt for either trial. We show, for the first time, that inhalation of vaporized nicotine increases arterial pressure in the seated, supine and head-up tilt positions - suggesting sympathomemetic properties. Although mild, acute increases in arterial pressure may seem harmless, it is possible that daily, continuous use of e-cigs could result in consistently elevated arterial pressure, resulting in higher afterload and chronic cardiac strain
Red blood cell transfusion and outcomes in patients with acute lung injury, sepsis and shock
Introduction: In this study, we sought to determine the association between red blood cell (RBC) transfusion and outcomes in patients with acute lung injury (ALI), sepsis and shock.Methods: We performed a secondary analysis of new-onset ALI patients enrolled in the Acute Respiratory Distress Syndrome Network Fluid and Catheter Treatment Trial (2000 to 2005) who had a documented ALI risk factor of sepsis or pneumonia and met shock criteria (mean arterial pressure (MAP) < 60 mmHg or vasopressor use) within 24 hours of randomization. Using multivariable logistic regression, we examined the association between RBC transfusion and 28-day mortality after adjustment for age, sex, race, randomization arm and Acute Physiology and Chronic Health Evaluation III score. Secondary end points included 90-day mortality and ventilator-free days (VFDs). Finally, we examined these end points among the subset of subjects meeting prespecified transfusion criteria defined by five simultaneous indicators: hemoglobin < 10.2 g/dL, central or mixed venous oxygen saturation < 70%, central venous pressure ℠8 mmHg, MAP ℠65 mmHg, and vasopressor use.Results: We identified 285 subjects with ALI, sepsis, shock and transfusion data. Of these, 85 also met the above prespecified transfusion criteria. Fifty-three (19%) of the two hundred eighty-five subjects with shock and twenty (24%) of the subset meeting the transfusion criteria received RBC transfusion within twenty-four hours of randomization. We found no independent association between RBC transfusion and 28-day mortality (odds ratio = 1.49, 95% CI (95% confidence interval) = 0.77 to 2.90; P = 0.23) or VFDs (mean difference = -0.35, 95% CI = -4.03 to 3.32; P = 0.85). Likewise, 90-day mortality and VFDs did not differ by transfusion status. Among the subset of patients meeting the transfusion criteria, we found no independent association between transfusion and mortality or VFDs.Conclusions: In patients with new-onset ALI, sepsis and shock, we found no independent association between RBC transfusion and mortality or VFDs. The physiological criteria did not identify patients more likely to be transfused or to benefit from transfusion. © 2011 Parsons et al. licensee BioMed Central Ltd
Parallelized computational 3D video microscopy of freely moving organisms at multiple gigapixels per second
To study the behavior of freely moving model organisms such as zebrafish
(Danio rerio) and fruit flies (Drosophila) across multiple spatial scales, it
would be ideal to use a light microscope that can resolve 3D information over a
wide field of view (FOV) at high speed and high spatial resolution. However, it
is challenging to design an optical instrument to achieve all of these
properties simultaneously. Existing techniques for large-FOV microscopic
imaging and for 3D image measurement typically require many sequential image
snapshots, thus compromising speed and throughput. Here, we present 3D-RAPID, a
computational microscope based on a synchronized array of 54 cameras that can
capture high-speed 3D topographic videos over a 135-cm^2 area, achieving up to
230 frames per second at throughputs exceeding 5 gigapixels (GPs) per second.
3D-RAPID features a 3D reconstruction algorithm that, for each synchronized
temporal snapshot, simultaneously fuses all 54 images seamlessly into a
globally-consistent composite that includes a coregistered 3D height map. The
self-supervised 3D reconstruction algorithm itself trains a
spatiotemporally-compressed convolutional neural network (CNN) that maps raw
photometric images to 3D topography, using stereo overlap redundancy and
ray-propagation physics as the only supervision mechanism. As a result, our
end-to-end 3D reconstruction algorithm is robust to generalization errors and
scales to arbitrarily long videos from arbitrarily sized camera arrays. The
scalable hardware and software design of 3D-RAPID addresses a longstanding
problem in the field of behavioral imaging, enabling parallelized 3D
observation of large collections of freely moving organisms at high
spatiotemporal throughputs, which we demonstrate in ants (Pogonomyrmex
barbatus), fruit flies, and zebrafish larvae
Social Influence in Televised Election Debates: A Potential Distortion of Democracy
A recent innovation in televised election debates is a continuous response measure (commonly referred to as the âwormâ) that allows viewers to track the response of a sample of undecided voters in real-time. A potential danger of presenting such data is that it may prevent people from making independent evaluations. We report an experiment with 150 participants in which we manipulated the worm and superimposed it on a live broadcast of a UK election debate. The majority of viewers were unaware that the worm had been manipulated, and yet we were able to influence their perception of who won the debate, their choice of preferred prime minister, and their voting intentions. We argue that there is an urgent need to reconsider the simultaneous broadcast of average response data with televised election debates
Author Correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases.
Emmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article
Intravenous iron for heart failure, iron deficiency definitions, and clinical response:the IRONMAN trial
BACKGROUND AND AIMS: What is the relationship between blood tests for iron deficiency, including anaemia, and the response to intravenous iron in patients with heart failure?METHODS: In the IRONMAN trial, 1137 patients with heart failure, ejection fraction †45%, and either serum ferritin < 100â
”g/L or transferrin saturation (TSAT) < 20% were randomized to intravenous ferric derisomaltose (FDI) or usual care. Relationships were investigated between baseline anaemia severity, ferritin and TSAT, to changes in haemoglobin from baseline to 4 months, Minnesota Living with Heart Failure (MLwHF) score and 6-minute walk distance achieved at 4 months, and clinical events, including heart failure hospitalization (recurrent) or cardiovascular death.RESULTS: The rise in haemoglobin after administering FDI, adjusted for usual care, was greater for lower baseline TSAT (Pinteraction < .0001) and ferritin (Pinteraction = .028) and more severe anaemia (Pinteraction = .014). MLwHF scores at 4 months were somewhat lower (better) with FDI for more anaemic patients (overall Pinteraction = .14; physical Pinteraction = .085; emotional Pinteraction = .043) but were not related to baseline TSAT or ferritin. Blood tests did not predict difference in achieved walking distance for those randomized to FDI compared to control. The absence of anaemia or a TSAT â„ 20% was associated with lower event rates and little evidence of benefit from FDI. More severe anaemia or TSAT < 20%, especially when ferritin was â„100â
”g/L, was associated with higher event rates and greater absolute reductions in events with FDI, albeit not statistically significant.CONCLUSIONS: This hypothesis-generating analysis suggests that anaemia or TSAT < 20% with ferritin > 100â
”g/L might identify patients with heart failure who obtain greater benefit from intravenous iron. This interpretation requires confirmation.</p
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