Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 47
Filter
2.
Biology (Basel) ; 11(5)2022 Apr 23.
Article in English | MEDLINE | ID: mdl-35625375

ABSTRACT

Autologous blood doping (ABD) refers to the transfusion of one's own blood after it has been stored. Although its application is prohibited in sports, it is assumed that ABD is applied by a variety of athletes because of its benefits on exercise performance and the fact that it is not detectable so far. Therefore, this study aims at identifying changes in hematological and hemorheological parameters during the whole course of ABD procedure and to relate those changes to exercise performance. Eight healthy men conducted a 31-week ABD protocol including two blood donations and the transfusion of their own stored RBC volume corresponding to 7.7% of total blood volume. Longitudinal blood and rheological parameter measurements and analyses of RBC membrane proteins and electrolyte levels were performed. Thereby, responses of RBC sub-populations-young to old RBC-were detected. Finally, exercise tests were carried out before and after transfusion. Results indicate a higher percentage of young RBC, altered RBC deformability and electrolyte concentration due to ABD. In contrast, RBC membrane proteins remained unaffected. Running economy improved after blood transfusion. Thus, close analysis of RBC variables related to ABD detection seems feasible but should be verified in further more-detailed studies.

4.
Kidney Int ; 100(6): 1227-1239, 2021 12.
Article in English | MEDLINE | ID: mdl-34537228

ABSTRACT

Anemia is a common complication of chronic kidney disease, affecting the quality of life of patients. Among various factors, such as iron and erythropoietin deficiency, reduced red blood cell (RBC) lifespan has been implicated in the pathogenesis of anemia. However, mechanistic data on in vivo RBC dysfunction in kidney disease are lacking. Herein, we describe the development of chronic kidney disease-associated anemia in mice with proteinuric kidney disease resulting from either administration of doxorubicin or an inducible podocin deficiency. In both experimental models, anemia manifested at day 10 and progressed at day 30 despite increased circulating erythropoietin levels and erythropoiesis in the bone marrow and spleen. Circulating RBCs in both mouse models displayed altered morphology and diminished osmotic-sensitive deformability together with increased phosphatidylserine externalization on the outer plasma membrane, a hallmark of RBC death. Fluorescence-labelling of RBCs at day 20 of mice with doxorubicin-induced kidney disease revealed premature clearance from the circulation. Metabolomic analyses of RBCs from both mouse models demonstrated temporal changes in redox recycling pathways and Lands' cycle, a membrane lipid remodeling process. Anemic patients with proteinuric kidney disease had an increased proportion of circulating phosphatidylserine-positive RBCs. Thus, our observations suggest that reduced RBC lifespan, mediated by altered RBC metabolism, reduced RBC deformability, and enhanced cell death contribute to the development of anemia in proteinuric kidney disease.


Subject(s)
Anemia , Renal Insufficiency, Chronic , Anemia/chemically induced , Animals , Erythrocytes , Humans , Longevity , Mice , Quality of Life , Renal Insufficiency, Chronic/complications
7.
J Clin Epidemiol ; 134: 150-159, 2021 06.
Article in English | MEDLINE | ID: mdl-33737070

ABSTRACT

OBJECTIVES: We apply a general case replacement framework for quantifying the robustness of causal inferences to characterize the uncertainty of findings from clinical trials. STUDY DESIGN AND SETTING: We express the robustness of inferences as the amount of data that must be replaced to change the conclusion and relate this to the fragility of trial results used for dichotomous outcomes. We illustrate our approach in the context of an RCT of hydroxychloroquine on pneumonia in COVID-19 patients and a cumulative meta-analysis of the effect of antihypertensive treatments on stroke. RESULTS: We developed the Robustness of an Inference to Replacement (RIR), which quantifies how many treatment cases with positive outcomes would have to be replaced with hypothetical patients who did not receive a treatment to change an inference. The RIR addresses known limitations of the Fragility Index by accounting for the observed rates of outcomes. It can be used for varying thresholds for inference, including clinical importance. CONCLUSION: Because the RIR expresses uncertainty in terms of patient experiences, it is more relatable to stakeholders than P-values alone. It helps identify when results are statistically significant, but conclusions are not robust, while considering the rareness of events in the underlying data.


Subject(s)
Antihypertensive Agents/therapeutic use , COVID-19 Drug Treatment , Hydroxychloroquine/therapeutic use , Meta-Analysis as Topic , Pneumonia, Viral/drug therapy , Randomized Controlled Trials as Topic , Research Design , Stroke/drug therapy , Humans , Pneumonia, Viral/virology , SARS-CoV-2
8.
Biology (Basel) ; 10(1)2021 Jan 11.
Article in English | MEDLINE | ID: mdl-33440902

ABSTRACT

Red blood cell (RBC) deformability is an essential component of microcirculatory function that appears to be enhanced by physiological shear stress, while being negatively affected by supraphysiological shears and/or free radical exposure. Given that blood contains RBCs with non-uniform physical properties, whether all cells equivalently tolerate mechanical and oxidative stresses remains poorly understood. We thus partitioned blood into old and young RBCs which were exposed to phenazine methosulfate (PMS) that generates intracellular superoxide and/or specific mechanical stress. Measured RBC deformability was lower in old compared to young RBCs. PMS increased total free radicals in both sub-populations, and RBC deformability decreased accordingly. Shear exposure did not affect reactive species in the sub-populations but reduced RBC nitric oxide synthase (NOS) activation and intriguingly increased RBC deformability in old RBCs. The co-application of PMS and shear exposure also improved cellular deformability in older cells previously exposed to reactive oxygen species (ROS), but not in younger cells. Outputs of NO generation appeared dependent on cell age; in general, stressors applied to younger RBCs tended to induce S-nitrosylation of RBC cytoskeletal proteins, while older RBCs tended to reflect markers of nitrosative stress. We thus present novel findings pertaining to the interplay of mechanical stress and redox metabolism in circulating RBC sub-populations.

9.
Am Psychol ; 76(1): 130-144, 2021 01.
Article in English | MEDLINE | ID: mdl-32202817

ABSTRACT

The Intergovernmental Panel on Climate Change has encouraged psychologists to become part of the integrated scientific effort to support the achievement of climate change targets such as keeping within 1.5°C or 2°C of global warming. To date, the typical psychological approach has been to demonstrate that specific concepts and theories can predict behaviors that contribute to or mitigate climate change. Psychologists need to go further and, in particular, show that integrating psychological concepts into feasible interventions can reduce greenhouse gas emissions far more than would be achieved without such integration. While critiquing some aspects of current approaches, we describe psychological research that is pointing the way by distinguishing different types of behavior, acknowledging sociocultural context, and collaborating with other disciplines. Engaging this challenge offers psychologists new opportunities for promoting mitigation, advancing psychological understanding, and developing better interdisciplinary interactions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Subject(s)
Global Warming/prevention & control , Psychology , Humans
10.
Cell Commun Signal ; 18(1): 155, 2020 09 18.
Article in English | MEDLINE | ID: mdl-32948210

ABSTRACT

BACKGROUND: Thrombospondin-1 (TSP-1), a Ca2+-binding trimeric glycoprotein secreted by multiple cell types, has been implicated in the pathophysiology of several clinical conditions. Signaling involving TSP-1, through its cognate receptor CD47, orchestrates a wide array of cellular functions including cytoskeletal organization, migration, cell-cell interaction, cell proliferation, autophagy, and apoptosis. In the present study, we investigated the impact of TSP-1/CD47 signaling on Ca2+ dynamics, survival, and deformability of human red blood cells (RBCs). METHODS: Whole-cell patch-clamp was employed to examine transmembrane cation conductance. RBC intracellular Ca2+ levels and multiple indices of RBC cell death were determined using cytofluorometry analysis. RBC morphology and microvesiculation were examined using imaging flow cytometry. RBC deformability was measured using laser-assisted optical rotational cell analyzer. RESULTS: Exposure of RBCs to recombinant human TSP-1 significantly increased RBC intracellular Ca2+ levels. As judged by electrophysiology experiments, TSP-1 treatment elicited an amiloride-sensitive inward current alluding to a possible Ca2+ influx via non-selective cation channels. Exogenous TSP-1 promoted microparticle shedding as well as enhancing Ca2+- and nitric oxide-mediated RBC cell death. Monoclonal (mouse IgG1) antibody-mediated CD47 ligation using 1F7 recapitulated the cell death-inducing effects of TSP-1. Furthermore, TSP-1 treatment altered RBC cell shape and stiffness (maximum elongation index). CONCLUSIONS: Taken together, our data unravel a new role for TSP-1/CD47 signaling in mediating Ca2+ influx into RBCs, a mechanism potentially contributing to their dysfunction in a variety of systemic diseases. Video abstract.


Subject(s)
CD47 Antigen/metabolism , Erythrocyte Deformability , Erythrocytes/cytology , Signal Transduction , Thrombospondin 1/metabolism , Calcium/metabolism , Cations, Divalent/metabolism , Cell Survival , Erythrocyte Membrane/metabolism , Erythrocytes/metabolism , Humans
11.
Clim Change ; 161(1): 1-8, 2020.
Article in English | MEDLINE | ID: mdl-32836574
12.
Opt Express ; 28(8): 11415-11423, 2020 Apr 13.
Article in English | MEDLINE | ID: mdl-32403653

ABSTRACT

An ultrafast Yb-doped thin-disk multi-pass laser amplifier system with flexible parameters for material processing is reported. We can generate bursts consisting of four pulses at a distance of 20 ns and a total energy of 46.7 mJ at a repetition rate of 25 kHz. In single-pulse operation, 1.5 kW of average output is achieved at 400 kHz when optimizing for a beam quality of M2 = 1.5. Alignment for maximum output power provides 1.9 kW at the same repetition rate. All results are obtained without chirped-pulse amplification in the multi-pass set-up. The application potential of the system is demonstrated exploring its performance in materials processing of dielectrics. Cleaving of 3.8-mm-thick SCHOTT borofloat glass with a velocity of 1200 mm/s is demonstrated with 300 W of input power. Single-pass modification of 30 mm borosilicate glass is enabled with a Bessel beam at 1 kW of average power delivered by four-pulse bursts of an energy of 30 mJ.

13.
Nature ; 577(7788): 74-78, 2020 01.
Article in English | MEDLINE | ID: mdl-31894145

ABSTRACT

To address global challenges1-4, 193 countries have committed to the 17 United Nations Sustainable Development Goals (SDGs)5. Quantifying progress towards achieving the SDGs is essential to track global efforts towards sustainable development and guide policy development and implementation. However, systematic methods for assessing spatio-temporal progress towards achieving the SDGs are lacking. Here we develop and test systematic methods to quantify progress towards the 17 SDGs at national and subnational levels in China. Our analyses indicate that China's SDG Index score (an aggregate score representing the overall performance towards achieving all 17 SDGs) increased at the national level from 2000 to 2015. Every province also increased its SDG Index score over this period. There were large spatio-temporal variations across regions. For example, eastern China had a higher SDG Index score than western China in the 2000s, and southern China had a higher SDG Index score than northern China in 2015. At the national level, the scores of 13 of the 17 SDGs improved over time, but the scores of four SDGs declined. This study suggests the need to track the spatio-temporal dynamics of progress towards SDGs at the global level and in other nations.


Subject(s)
Sustainable Development/trends , China , Time
14.
One Earth ; 2(4): 306-308, 2020 Apr 24.
Article in English | MEDLINE | ID: mdl-34171026

ABSTRACT

In April 1970, the first Earth Day engaged millions of people in thousands of events around the US. Those events reflected the emergence of a new form of environmentalism. Many of the themes present 50 years ago persist, but in the US environmental issues have become more politically polarized, and it is unclear whether such value conflicts will persist in the future.

15.
J Clin Med ; 8(12)2019 Dec 05.
Article in English | MEDLINE | ID: mdl-31817545

ABSTRACT

Patients with sickle cell anemia (SCA) show impaired ventilatory efficiency, altered blood rheology, high levels of oxidative/nitrosative stress and enhanced hemolysis with large amounts of circulating free hemoglobin, which reduces nitric oxide (NO) bioavailability. The aim of the study was to investigate whether physical exercise could improve these physiological and biological markers described to contribute to SCA pathophysiology. Twelve SCA patients participated in a controlled six weeks training program with moderate volume (two sessions per week with 15-30 min duration per session) and intensity (70% of the first ventilatory threshold). Parameters were compared before (T0) and after (T1) training. Daily activities were examined by a questionnaire at T0 and one year after the end of T1. Results revealed improved ventilatory efficiency, reduced nitrosative stress, reduced plasma free hemoglobin concentration, increased plasma nitrite levels and altered rheology at T1 while no effect was observed for exercise performance parameters or hematological profile. Red blood cell (RBC) NO parameters indicate increased NO bioavailability which did not affect RBC deformability. Participants increased their daily life activity level. The data from this pilot study concludes that even low intensity activities are feasible and could be beneficial for the health of SCA patients.

16.
Sci Rep ; 9(1): 11813, 2019 08 14.
Article in English | MEDLINE | ID: mdl-31413300

ABSTRACT

Sickle cell anaemia (SCA) is characterized by reduced red blood cell (RBC) deformability and nitric oxide (NO) bioavailability. The aim of the study was to investigate whether exercise might affect these parameters in SCA. SCA patients and healthy controls (AA) performed an acute submaximal exercise test until subjects reached the first ventilatory threshold (VT 1). Blood was sampled at rest and at VT 1. At rest, free haemoglobin level was higher and RBC count, haemoglobin and haematocrit were lower in SCA compared to AA. RBC deformability was lower in SCA. Exercise had no effect on the tested parameters. RBC NO level was higher in SCA compared to AA at rest and significantly decreased after exercise in SCA. This might be related to a reduction in RBC-NO synthase (RBC-NOS) activation which was only observed in SCA after exercise. Free radical levels were higher in SCA at rest but concentration was not affected by exercise. Marker for lipid peroxidation and antioxidative capacity were similar in SCA and AA and not affected by exercise. In conclusion, a single acute submaximal bout of exercise has no deleterious effects on RBC deformability or oxidative stress markers in SCA, and seems to modulate RBC-NOS signalling pathway.


Subject(s)
Anemia, Sickle Cell/metabolism , Erythrocyte Deformability , Erythrocytes/enzymology , Exercise/physiology , Nitric Oxide Synthase/metabolism , Signal Transduction , Adolescent , Anemia, Sickle Cell/blood , Anemia, Sickle Cell/enzymology , Case-Control Studies , Female , Humans , Male , Oxidative Stress
17.
Proc Natl Acad Sci U S A ; 115(49): 12334-12336, 2018 12 04.
Article in English | MEDLINE | ID: mdl-30459271
18.
Data Brief ; 19: 570-585, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29900357

ABSTRACT

The data presented in this article are related to the research article entitled "The Voluntary Coffee Standard Index (VOCSI). Developing a composite Index to Assess and Compare the Institutional Strength of Mainstream Voluntary Sustainability Standards in the Global Coffee Industry" (Dietz et al., 2018) in press) [1]. The VOCSI presents the most detailed comparison all major voluntary sustainability standards (VSS) that currently exist in global coffee production. This Data in Brief contains the database that we have generated to set up the VOCSI. We publish this dataset in order to facilitate further critical or extended analyzes.

19.
PLoS One ; 12(10): e0186049, 2017.
Article in English | MEDLINE | ID: mdl-29069087

ABSTRACT

Scientists who perform environmental research on policy-relevant topics face challenges when communicating about how values may have influenced their research. This study examines how citizens view scientists who publicly acknowledge values. Specifically, we investigate whether it matters: if citizens share or oppose a scientist's values, if a scientist's conclusions seem contrary to or consistent with the scientist's values, and if a scientist is assessing the state of the science or making a policy recommendation. We conducted two 3x2 factorial design online experiments. Experiment 1 featured a hypothetical scientist assessing the state of the science on the public-health effects of exposure to Bisphenol A (BPA), and Experiment 2 featured a scientist making a policy recommendation on use of BPA. We manipulated whether or not the scientist expressed values and whether the scientist's conclusion appeared contrary to or consistent with the scientist's values, and we accounted for whether or not subjects' values aligned with the scientist's values. We analyzed our data with ordinary least squares (OLS) regression techniques. Our results provide at least preliminary evidence that acknowledging values may reduce the perceived credibility of scientists within the general public, but this effect differs depending on whether scientists and citizens share values, whether scientists draw conclusions that run contrary to their values, and whether scientists make policy recommendations.


Subject(s)
Environment , Public Opinion , Research , Science , Benzhydryl Compounds/toxicity , Environmental Exposure , Humans , Phenols/toxicity
20.
Chemistry ; 23(62): 15583-15587, 2017 Nov 07.
Article in English | MEDLINE | ID: mdl-28869692

ABSTRACT

The homodinuclear ruthenium(II) complex [{Ru(l-N4 Me2 )}2 (µ-tape)](PF6 )4 {[1](PF6 )4 } (l-N4 Me2 =N,N'-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane, tape=1,6,7,12-tetraazaperylene) can store one or two electrons in the energetically low-lying π* orbital of the bridging ligand tape. The corresponding singly and doubly reduced complexes [{Ru(l-N4 Me2 )}2 (µ-tape.- )](PF6 )3 {[2](PF6 )3 } and [{Ru(l-N4 Me2 )}2 (µ-tape2- )](PF6 )2 {[3](PF6 )2 }, respectively, were electrochemically generated, successfully isolated and fully characterized by single-crystal X-ray crystallography, spectroscopic methods and magnetic susceptibility measurements. The singly reduced complex [2](PF6 )3 contains the π-radical tape.- and the doubly reduced [3](PF6 )2 the diamagnetic dianion tape2- as bridging ligand, respectively. Nucleophilic aromatic substitution at the bridging tape in [1]4+ by two sulfite units gave the complex [{Ru(l-N4 Me2 )}2 {µ-tape-(SO3 )2 }]2+ ([4]2+ ). Complex dication [4]2+ was exploited as a redox mediator between an anaerobic homogenous reaction solution of an enzyme system (sulfite/sulfite oxidase) and the electrode via participation of the low-energy π*-orbital of the disulfonato-substituted bridging ligand tape-(SO3 )22- (Ered1 =-0.1 V versus Ag/AgCl/1 m KCl in water).

SELECTION OF CITATIONS
SEARCH DETAIL
...