Radboud University Nijmegen

About: Radboud University Nijmegen is a education organization based out in Nijmegen, Gelderland, Netherlands. It is known for research contribution in the topics: Population & Context (language use). The organization has 35417 authors who have published 83035 publications receiving 3285064 citations. The organization is also known as: Catholic University of Nijmegen & Radboud University.

Effect of Aging and Physical Activity on Left Ventricular Compliance

Abstract: Background— Left ventricular compliance appears to decrease with aging, which may contribute to the high incidence of heart failure in the elderly. However, whether this change is an inevitable consequence of senescence or rather secondary to reduced physical activity is unknown. Methods and Results— Twelve healthy sedentary seniors (69.8±3 years old; 6 women, 6 men) and 12 Masters athletes (67.8±3 years old; 6 women, 6 men) underwent pulmonary artery catheterization to define Starling and left ventricular pressure-volume curves. Data were compared with those obtained in 14 young but sedentary control subjects (28.9±5 years old; 7 women, 7 men). Pulmonary capillary wedge pressures and left ventricular end-diastolic volumes by use of echocardiography were measured at baseline, during decreased cardiac filling by use of lower-body negative pressure (−15 and −30 mm Hg), and after saline infusion (15 and 30 mL/kg). Stroke volume for any given filling pressure was greater in Masters athletes compared with the ...

Flow-mediated dilation and cardiovascular event prediction: does nitric oxide matter?

Abstract: Endothelial dysfunction is an early atherosclerotic event that precedes clinical symptoms and may also render established plaque vulnerable to rupture. Noninvasive assessment of endothelial function is commonly undertaken using the flow-mediated dilation (FMD) technique. Some studies indicate that FMD possesses independent prognostic value to predict future cardiovascular events that may exceed that associated with traditional risk factor assessment. It has been assumed that this association is related to the proposal that FMD provides an index of endothelium-derived nitric oxide (NO) function. Interestingly, placement of the occlusion cuff during the FMD procedure alters the shear stress stimulus and NO dependency of the resulting dilation: cuff placement distal to the imaged artery leads to a largely NO-mediated response, whereas proximal cuff placement leads to dilation which is less NO dependent. We used this physiological observation and the knowledge that prognostic studies have used both approaches to examine whether the prognostic capacity of FMD is related to its role as a putative index of NO function. In a meta-analysis of 14 studies (>8300 subjects), we found that FMD derived using a proximal cuff was at least as predictive as that derived using distal cuff placement, despite the latter being more NO dependent. This suggests that, whilst FMD is strongly predictive of future cardiovascular events, this may not solely be related to its assumed NO dependency. Although this finding should be confirmed with more and larger studies, we suggest that any direct measure of vascular (endothelial) function may provide independent prognostic information in humans.

Enrichment and molecular detection of denitrifying methanotrophic bacteria of the NC10 phylum.

Abstract: Anaerobic methane oxidation coupled to denitrification was recently assigned to bacteria belonging to the uncultured phylum NC10. In this study, we incubated sediment from a eutrophic ditch harboring a diverse community of NC10 bacteria in a bioreactor with a constant supply of methane and nitrite. After 6 months, fluorescence in situ hybridization showed that NC10 bacteria dominated the resulting population. The enrichment culture oxidized methane and reduced nitrite to dinitrogen gas. We assessed NC10 phylum diversity in the inoculum and the enrichment culture, compiled the sequences currently available for this bacterial phylum, and showed that of the initial diversity, only members of one subgroup had been enriched. The growth of this subgroup was monitored by quantitative PCR and correlated to nitrite-reducing activity and the total biomass of the culture. Together, the results indicate that the enriched subgroup of NC10 bacteria is responsible for anaerobic methane oxidation coupled to nitrite reduction. Due to methodological limitations (a strong bias against NC10 bacteria in 16S rRNA gene clone libraries and inhibition by commonly used stopper material) the environmental distribution and importance of these bacteria could be largely underestimated at present.

What's in a Fashion? Interpretative Viability and Management Fashions

Abstract: Building and reacting on the most influential article on the topic, namely, `Management Fashion' by Abrahamson (Academy of Management Review 21(1), 1996), we propose that management fashions are best conceptualized as `the production and consumption of temporarily intensive management discourse, and the organizational changes induced by and associated with this discourse'. This conceptualization allows us to take account of `interpretative viability', a certain degree of ambiguity about a fashion `s content, and its consequences for the dynamics involved in the ongoing shaping and reshaping of a concept's connotations. Our arguments are illustrated by drawing on a variety of empirical work on Business Process Reengineering in the Netherlands.