Dynamic muscle quality of the plantar flexors is impaired in claudicant patients with peripheral arterial disease and associated with poorer walking endurance

Objective Peripheral arterial disease and intermittent claudication (PAD-IC) negatively affects physical activity and function. There is evidence for plantarflexor muscle dysfunction and weakness; however, the extent to which this dysfunction can be attributed to reduced muscle size or quality, or both, is not yet known. This study investigated whether in vivo plantarflexor muscle quality during static and dynamic contractions is altered by PAD-IC and whether such changes are associated with impaired walking endurance according to initial and absolute claudication distances. Methods The study recruited 22 participants, consisting of 10 healthy controls and 12 claudicant patients with occlusion of the superficial femoral artery (seven unilateral and five bilateral). Muscle quality of the combined gastrocnemius muscles during static contractions was calculated by normalizing the estimated maximal potential muscle force to the physiological cross-sectional area of the lateral and medial gastrocnemius. Muscle quality during dynamic contractions of the combined plantarflexor muscles was calculated as the ratio of peak voluntary concentric plantarflexor power and the summed volume of lateral and medial gastrocnemius. Results Dynamic muscle quality was 24% lower in the claudicating-limb and asymptomatic-limb groups compared with controls (P = .017 and P = .023). The differences were most apparent at the highest contraction velocity (180°/s). Dynamic muscle quality was associated with reduced walking endurance (R = 0.689, P = .006 and R = 0.550, P = .042 for initial and absolute claudication distance, respectively). The claudicating-limb group demonstrated a trend toward reduced static muscle quality compared with controls (22%, P = .084). The relative contribution of the soleus muscle to plantarflexion maximum voluntary contraction was significantly higher in the claudicating-limb and asymptomatic-limb groups than in controls (P = .012 and P = .018). Conclusions The muscle strength of the plantarflexors in those with PAD-IC appears to be impaired at high contraction velocities. This may be explained by some reduction in gastrocnemii muscle quality and a greater reliance on the prominently type I-fibered soleus muscle. The reduced dynamic capability of the plantarflexor muscles was associated with disease severity and walking ability; therefore, efforts to improve plantarflexor power through dynamic exercise intervention are vital to maintain functional performance

Biomechanical demands of the 2-step transitional gait cycles linking level gait and stair descent gait in older women

Stair descent is an inherently complex form of locomotion posing a high falls risk for older adults, specifically when negotiating the transitional gait cycles linking level gait and descent. The aim of this study was to enhance our understanding of the biomechanical demands by comparing the demands of these transitions. Lower limb kinematics and kinetics of the 2-step transitions linking level and descent gait at the top (level-to-descent) and the bottom (descent-to-level) of the staircase were quantified in 36 older women with no falls history. Despite undergoing the same vertical displacement (2-steps), the following significant (p<.05) differences were observed during the top transition compared to the bottom transition: reduced step velocity; reduced hip extension and increased ankle dorsiflexion (late stance/pre-swing); reduced ground reaction forces, larger knee extensor moments and powers (absorption; late stance); reduced ankle plantarflexor moments (early and late stance) and increased ankle powers (mid-stance). Top transition biomechanics were similar to those reported previously for continuous descent. Kinetic differences at the knee and ankle signify the contrasting and prominent functions of controlled lowering during the top transition and forward continuance during the bottom transition. The varying musculoskeletal demands encountered during each functional sub-task should be addressed in falls prevention programmes with elderly populations where the greatest clinical impact may be achieved. Knee extensor eccentric power through flexion exercises would facilitate a smooth transition at the top and improving ankle plantarflexion strength during single and double limb stance activities would ease the transition into level gait following continuous descent

Redox-Rich Metallocene Tetrazene Complexes: Synthesis, Structure, Electrochemistry, and Catalysis

Thermal or photochemical metal-centered cycloaddition reactions of azidocobaltocenium hexafluoridophosphate or azidoferrocene with (cyclooctadiene)(cyclopentadienyl)cobalt- (I) afforded the first metallocenyl-substituted tetrazene cyclopentadienyl cobalt complexes together with azocobaltocenium or azoferrocene as side products. The trimetallic CpCo compounds are highly conjugated, colored, and redox-active metallo-aromatic compounds, as shown by their spectroscopic, structural, and electrochemical properties. The CpCo-tetrazenido complex with two terminally appended cobaltocene units catalyzes electrochemical proton reduction from acetic acid at a mild overpotential (0.35 V). Replacing cobaltocene with ferrocene moieties rendered the complex inactive toward catalysis.Austrian Science Fund (FWF), Christian Doppler Association (Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development), OMV, Marie Skłodowska-Curie, Deutsche Forschungsgemeinschaf

The pulvinar nucleus and antidepressant treatment : dynamic modeling of antidepressant response and remission with ultra-high field functional MRI

Functional magnetic resonance imaging (fMRI) successfully disentangled neuronal pathophysiology of major depression (MD), but only a few fMRI studies have investigated correlates and predictors of remission. Moreover, most studies have used clinical outcome parameters from two time points, which do not optimally depict differential response times. Therefore, we aimed to detect neuronal correlates of response and remission in an antidepressant treatment study with 7 T fMRI, potentially harnessing advances in detection power and spatial specificity. Moreover, we modeled outcome parameters from multiple study visits during a 12-week antidepressant fMRI study in 26 acute (aMD) patients compared to 36 stable remitted (rMD) patients and 33 healthy control subjects (HC). During an electrical painful stimulation task, significantly higher baseline activity in aMD compared to HC and rMD in the medial thalamic nuclei of the pulvinar was detected (p = 0.004, FWE-corrected), which was reduced by treatment. Moreover, clinical response followed a sigmoid function with a plateau phase in the beginning, a rapid decline and a further plateau at treatment end. By modeling the dynamic speed of response with fMRI-data, perigenual anterior cingulate activity after treatment was significantly associated with antidepressant response (p < 0.001, FWE-corrected). Temporoparietal junction (TPJ) baseline activity significantly predicted non-remission after 2 antidepressant trials (p = 0.005, FWE-corrected). The results underline the importance of the medial thalamus, attention networks in MD and antidepressant treatment. Moreover, by using a sigmoid model, this study provides a novel method to analyze the dynamic nature of response and remission for future trials

Automated ROI-Based Labeling for Multi-Voxel Magnetic Resonance Spectroscopy Data Using FreeSurfer

Purpose: Advanced analysis methods for multi-voxel magnetic resonance spectroscopy (MRS) are crucial for neurotransmitter quantification, especially for neurotransmitters showing different distributions across tissue types. So far, only a handful of studies have used region of interest (ROI)-based labeling approaches for multi-voxel MRS data. Hence, this study aims to provide an automated ROI-based labeling tool for 3D-multi-voxel MRS data.Methods: MRS data, for automated ROI-based labeling, was acquired in two different spatial resolutions using a spiral-encoded, LASER-localized 3D-MRS imaging sequence with and without MEGA-editing. To calculate the mean metabolite distribution within selected ROIs, masks of individual brain regions were extracted from structural T1-weighted images using FreeSurfer. For reliability testing of automated labeling a comparison to manual labeling and single voxel selection approaches was performed for six different subcortical regions.Results: Automated ROI-based labeling showed high consistency [intra-class correlation coefficient (ICC) &gt; 0.8] for all regions compared to manual labeling. Higher variation was shown when selected voxels, chosen from a multi-voxel grid, uncorrected for voxel composition, were compared to labeling methods using spatial averaging based on anatomical features within gray matter (GM) volumes.Conclusion: We provide an automated ROI-based analysis approach for various types of 3D-multi-voxel MRS data, which dramatically reduces hands-on time compared to manual labeling without any possible inter-rater bias

Comparison of measured and modelled uv indices for the assessment of health risks

The World Health Organisation (WHO) and the World Meteorological Organisation (WMO) have jointly recommended that the UV Index (UVI) should be used to inform the public about possible health risks due to overexposure to solar radiation, especially skin damage. To test the current operational status of measuring and modelling techniques used in providing the public with UVI information, this article compares cloudless sky UVIs (measured using five instruments at four locations with different latitudes and climate) with the results of 13 models used in UVI forecasting schemes. For the models, only location, total ozone and solar zenith angle were provided as input parameters. In many cases the agreement is acceptable, i.e. less than 0.5 UVI. Larger differences may originate from instrumental errors and shortcomings in the models and their input parameters. A possible explanation for the differences between models is the treatment of the unknown input parameters, especially aerosols

Extreme events in total ozone over the Northern mid-latitudes: an analysis based on long-term data sets from five European ground-based stations

We apply methods from extreme value theory to identify extreme events in high (termed EHOs) and low (termed ELOs) total ozone and to describe the distribution tails (i.e. very high and very low values) of five long-term European ground-based total ozone time series. The influence of these extreme events on observed mean values, long-term trends and changes is analysed. The results show a decrease in EHOs and an increase in ELOs during the last decades, and establish that the observed downward trend in column ozone during the 1970-1990s is strongly dominated by changes in the frequency of extreme events. Furthermore, it is shown that clear 'fingerprints' of atmospheric dynamics (NAO, ENSO) and chemistry [ozone depleting substances (ODSs), polar vortex ozone loss] can be found in the frequency distribution of ozone extremes, even if no attribution is possible from standard metrics (e.g. annual mean values). The analysis complements earlier analysis for the world's longest total ozone record at Arosa, Switzerland, confirming and revealing the strong influence of atmospheric dynamics on observed ozone changes. The results provide clear evidence that in addition to ODS, volcanic eruptions and strong/moderate ENSO and NAO events had significant influence on column ozone in the European sector

Age-related changes in physical functioning: Correlates between objective and self-reported outcomes

Objectives: To quantify the variance attributable to age and estimate annual decline in physical function and self-reported health using a battery of outcome measures in healthy older females. To determine whether self-reported functional losses are similar to those measured objectively and which best represent overall physical capacity. Design: Experimental study, cross-sectional analysis. Setting: Human Performance Laboratory, University setting. Participants: Thirty-nine community-dwelling women (mean [SD] age. =. 71.5 [7.3] years, range 60 to 83 years) completed a battery of objective measures of function and a self-reported health status survey. Main outcome measures: Objective measures: gait speed; TUG test; sit-to-stand; concentric knee flexor and extensor moments; self-reported: the SF-36. Results: Using a cross-sectional approach, annual declines were estimated for: TUG time (2.1%); gait speed (1.2%); knee extensor (2.2%) and flexor moments (3.0%); and self-reported Physical Functioning (0.9 to 1.2%) (p≤0.001). Linear regression indicated that age explained moderate variance in the objective (R2=21 to 34%) and self-reported (R2=14 to 28%) outcomes. TUG time and gait speed was significantly correlated with all objective outcomes except sit-to-stand (r=0.46 to 0.83) and most of the self-reported (r=0.40 to 0.63) outcomes (p<0.01). Conclusions: Age-related functional deterioration was estimated precisely across both objective and self-reported outcomes. Greater strength losses for the knee flexors compared to the extensors indicate an unequal strength loss of antagonistic muscle pairs which has implications for the safe completion of many functional tasks including obstacle negotiation, stair locomotion, postural transitions, and ultimately knee joint stability. Furthermore, walking speed and TUG time correlated most strongly with many of the outcomes highlighting their importance as global indicators of physical capacity

Internet of Things for Sustainable Human Health

The sustainable health IoT has the strong potential to bring tremendous improvements in human health and well-being through sensing, and monitoring of health impacts across the whole spectrum of climate change. The sustainable health IoT enables development of a systems approach in the area of human health and ecosystem. It allows integration of broader health sub-areas in a bigger archetype for improving sustainability in health in the realm of social, economic, and environmental sectors. This integration provides a powerful health IoT framework for sustainable health and community goals in the wake of changing climate. In this chapter, a detailed description of climate-related health impacts on human health is provided. The sensing, communications, and monitoring technologies are discussed. The impact of key environmental and human health factors on the development of new IoT technologies also analyzed

Molecular Imaging in Adult Attention Deficit/Hyperactivity Disorder

Die Aufmerksamkeitsdefizit- und Hyperaktivitässtörung (ADHS) weist hohe Prävalenzraten und eine hohe Korrelation mit genetischen Faktoren auf, wobei bis zu zwei Drittel der Patienten, die im Kindesalter an ADHS erkrankt sind noch im Erwachsenenalter darunter leiden. Die Pathophysiologie von ADHS wird eng mit einer dysfunktionalen Konnektivität innerhalb und zwischen verschiedenen Hirnregionen in Verbindung gebracht, welche durch verschiedene Neurotransmittersysteme gesteuert wird. Stimulanzien und Nicht-Stimulanzien werden häufig bei ADHS verordnet, modulieren vorrangig das noradrenerge und dopaminerge Transmittersystem im zentralen Nervensystem und führen klinisch nachweislich zu einer Reduktion der Aufmerksamkeitsstörung, Impulsivität und Hyperaktivität. Zusätzlich kommt der serotonergen Transmission bei ADHS eine zentrale Bedeutung zu, da sie bei hyperaktivem und impulsivem Verhalten sowie bei kognitiven Prozessen, welche durch Emotionen beeinflusst werden, eine große Rolle spielt. Die komplexen zugrundeliegenden neuronalen Mechanismen von ADHS sowie der Mechanismus wie Psychopharmaka ihre Wirkung erzielen sind bis dato noch teilweise ungeklärt, weswegen mehr Informationen über diese Neurotransmittersysteme von zentraler Bedeutung sind. Im Rahmen dieser Doktorarbeit wurde der Noradrenalintransporter (synonym: Norepinephrintransporter; NET) sowie der Serotonintransporter (SERT) in vivo bei Patienten mit ADHS untersucht. Zur Quantifizierung von NET und SERT im Gehirn wurde Positronenemissionstomographie (PET) und (S,S)-[18F]FMeNER-D2 für die Messung des NET oder [11C]DASB für die von SERT verwendet. Die Quantifizierung des NET bei Patienten mit ADHS wurde weltweit erstmalig im Zuge unserer ersten Studie durchgeführt. Es wurde kein signifikanter Unterschied in der Häufigkeit von NET bei Patienten mit ADHS im Vergleich zu gesunden Kontrollprobanden gefunden. In unserer zweiten Publikation haben wir im Zuge genetischer Analysen einen genetischen Effekt auf die NET Expression bei Patienten mit ADHS gefunden. Weiters habe ich den SERT bei Patienten untersucht. Die herkömmliche Datenanalyse hat keinen Unterschied von SERT bei ADHS im Vergleich zu gesunden Kontrollprobanden gezeigt. Zusätzlich wurde erstmalig eine interregionale Korrelationsanaylse anhand des SERT Bindungspotentials durchgeführt, die signifikante Unterschiede in der Korrelation zwischen Hippokampus und Prekuneus zwischen Patienten mit ADHS und gesunden Kontrollprobanden zeigen konnte. Die Resultate dieser Bildgebungsuntersuchungen geben einerseits Aufschluss über die Quantität von NET und SERT bei ADHS, wobei keine Unterschiede zwischen Patienten mit ADHS und gesunden Kontrollprobanden nachgewiesen wurde. Dies deutet darauf hin, dass weder die Häufigkeit von NET noch die von SERT eine zentral Bedeutung für die pathophysiologischen neuronalen Mechanismen von ADHS haben dürfte. Andererseits konnten wir einen genetischen Einfluss auf die Expression von NET bei ADHS darstellen und durch die erstmalige Anwendung einer interregionalen Korrelationsanalyse gegenwärtige Analyseverfahren im Bereich der PET Bildgebungsstudien erweitern. Insgesamt tragen die Resultate dieser PET Untersuchung zu einem besseren Verständnis der ADHS-spezifischen neurobiologischen Mechanismen bei.Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent and heritable neurodevelopment disorder, with 40 to 60% of affected children suffering from ADHD also in adulthood. The ADHD pathophysiology is linked to dysfunctional connectivity within and between brain regions, which are modulated by neurotransmitters systems. Frequently prescribed treatments for ADHD, including stimulants and non-stimulants, alter norepinephrinergic and dopaminergic signaling in the central nervous system and thereby alleviate ADHD symptoms. In addition, serotonergic signaling is associated with hyperactivity, impulsivity and cognitive-emotional processes, which all represent symptoms that are present in ADHD. The causal complex neuronal mechanisms of ADHD and the way psychopharmacological therapy unfolds its efficacy are until now not entirely disclosed, thus it is of critical and public interest to gather more information of neurotransmitter signaling in ADHD. This thesis project was designed to investigate proteins as the norepinephrine and serotonin transporter (NET, SERT) in vivo in patients with ADHD. To evaluate NET and SERT expression, we used positron emission tomography (PET) and the radioligands (S,S)-[18F]FMeNER-D2 for NET quantification and [11C]DASB for SERT quantification. In our first study we investigated NET binding in ADHD for the first time worldwide. There was no significant difference in NET binding in patients with ADHD compared to healthy control subjects. In the second publication, we showed an effect of genotype on NET binding, implicating a genetic influence on the expression of the NET in ADHD. Furthermore in the third study, I quantified SERT levels in patients with ADHD and found no difference in SERT binding between patients and healthy controls in specific brain regions. However, I applied interregional molecular correlational analysis of the SERT binding, and I revealed significant differences in interregional correlations between the hippocampus and precuneus in patients with ADHD compared to healthy control subjects. The results of these imaging investigations provide needed information on the NET and SERT distribution in ADHD. The revealed lack of difference in NET and SERT binding between groups suggest that neither NET nor SERT availability is of critical relevance for the pathophysiology of ADHD. In addition, we found a genetic impact on NET binding in ADHD patients compared to healthy subjects, thus supporting previous genetic findings and underling a biological component in ADHD. To assess associations of SERT BPND between brain regions, I expanded conventional PET imaging analysis through performing interregional molecular correlational analysis of SERT binding. I aimed to capture the complexity of brain interactions rather than higher or lower SERT levels in a specific region and found differences of interregional associations in patients with ADHD. The results help to develop a much broader understanding of the basic neurochemical constitution of ADHD.Arbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüftAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersWien, Univ., Diss., 2016(VLID)194869