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141.
Geertje A. M. Ari?ns Willem van Mechelen Han C. G. Kemper Jos W. R. Twisk Willem van Mechelen 《European journal of applied physiology and occupational physiology》1997,76(3):214-220
The purpose of this study was to describe the longitudinal development of running economy [defined as the oxygen uptake (V˙O2) at a submaximal running speed] in males and females from teenage to young adult age using data from the Amsterdam Growth
and Health Study. Submaximal V˙O2 (in ml · kg−1· min−1) was measured in 84 males and 98 females while they ran on a treadmill at a constant speed of 8 km · h−1 for 6 min at three different treadmill slopes (0%, 2.5% and 5%). This test was carried out six times, on the same subjects
at the ages of 13, 14, 15, 16, 21, and 27 years. The longitudinal development of running economy in males and females was
analysed using a two-way analysis of variance for repeated measurements. At all three slopes, a significant decrease in V˙O2 with increasing age was found for both males and females, implying a significant increase in running economy for both sexes.
Males showed significantly higher V˙O2 values than females at all ages measured and for all three slopes, suggesting that females have a significantly higher running
economy than males. In order to make a better comparison of the V˙O2 of individuals of different sizes, allometric models were used; power function ratios were constructed in which body mass
was expressed to an exponential power. Following this analysis the difference in submaximal V˙O2 and running economy between males and females appeared even larger.
Accepted: 20 February 1997 相似文献
142.
Janine JH Oosterhof G Jolanda Elving Ietse Stokroos Arie van nieuw Amerongen Henny C van der Mei Henk J Busscher 《Biofouling》2013,29(6):347-353
The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses after biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance. 相似文献
143.
Eveline S. J. M. de Bont Anita E. Niemarkt Rienk Y. J. Tamminga Jan L. L. Kimpen Willem A. Kamps Lou H. M. F. de Leij 《Histochemistry and cell biology》1996,106(6):593-598
Lipopolysaccharide (LPS) can induce monocytes to produce various cytokines such as tumor necrosis factor α (TNFα) and interleukin
1β (IL-1β). In the present study, the kinetics of both intracellular and extracellular accumulation of TNFα and IL-1β in LPS
stimulated mononuclear cell (MNC) cultures has been determined. A three-color-immunofluorescence technique was used to detect
intracellular accumulation of cytokines. Intracellular accumulation of TNFα in monocytes starts shortly after initiation of
the culture; i.e., TNFα is detectable after 1 h, reaching a peak level after 3–4 hours with 50–65% of monocytes staining positive.
In parallel with its increased intracellular presence, TNFα was also found in the culture supernatant. The intracellular accumulation
of IL-1β in monocytes became detectable after 2 h of culture in the presence of LPS. After 4 h, a plateau was reached, with
90% of the monocytes being positive. In parallel, but with a little delay, IL-1β could be detected in the culture supernatant.
TNFα and IL-1β can be produced simultaneously in the same monocytes as was shown by a three-color-immunofluorescence technique.
It is concluded that TNFα and IL-1β are good parameters for the early measurement of monocyte activation and that both the
intracellular accumulation in monocytes and the amount of secreted cytokines can be used for such a purpose. The intracellular
accumulation in monocytes can be measured by the three-color-immunofluorescence technique described.
Accepted: 27 August 1996 相似文献
144.
145.
Carlier SG Coen VL Sabaté M Kay IP Ligthart JM Van Der Giessen WJ Levendag PC Bom K Serruys PW 《International journal of cardiovascular interventions》2000,3(1):3-12
Intracoronary brachytherapy has recently emerged as a new therapy to prevent restenosis. Initial experimental work was achieved in animal models and the results were assessed by histomorphometry. Initial clinical trials used angiography to guide dosimetry and to assess efficacy. Intravascular ultrasound (IVUS) permits tomographic examination of the vessel wall, elucidating the true morphology of the lumen and transmural components, which cannot be investigated on the lumenogram obtained by angiography. This paper reviews the use of IVUS in the clinical studies of brachytherapy conducted to date. IVUS allows clinicians to make a thorough assessment of the remodeling of the vessel and appears to have a major role to play in facilitating understanding of the underlying mechanisms of action in this emerging field. The authors propose that state-of-the-art IVUS techniques should be employed to further knowledge of the mechanisms of action of brachytherapy in atherosclerotic human coronary arteries. 相似文献
146.
147.
van der Heide LP Kamal A Artola A Gispen WH Ramakers GM 《Journal of neurochemistry》2005,94(4):1158-1166
Insulin and its receptor are both present in the central nervous system and are implicated in neuronal survival and hippocampal synaptic plasticity. Here we show that insulin activates phosphatidylinositol 3-kinase (PI3K) and protein kinase B (PKB), and results in an induction of long-term depression (LTD) in hippocampal CA1 neurones. Evaluation of the frequency-response curve of synaptic plasticity revealed that insulin induced LTD at 0.033 Hz and LTP at 10 Hz, whereas in the absence of insulin, 1 Hz induced LTD and 100 Hz induced LTP. LTD induction in the presence of insulin required low frequency synaptic stimulation (0.033 Hz) and blockade of GABAergic transmission. The LTD or LTP induced in the presence of insulin was N-methyl-d-aspartate (NMDA) receptor specific as it could be inhibited by alpha-amino-5-phosphonopentanoic acid (APV), a specific NMDA receptor antagonist. LTD induction was also facilitated by lowering the extracellular Mg(2+) concentration, indicating an involvement of NMDA receptors. Inhibition of PI3K signalling or discontinuing synaptic stimulation also prevented this LTD. These results show that insulin modulates activity-dependent synaptic plasticity, which requires activation of NMDA receptors and the PI3K pathway. The results obtained provide a mechanistic link between insulin and synaptic plasticity, and explain how insulin functions as a neuromodulator. 相似文献
148.
149.
Kristof Lodewijks Jef Ryken Willem Van Roy Gustaaf Borghs Liesbet Lagae Pol Van Dorpe 《Plasmonics (Norwell, Mass.)》2013,8(3):1379-1385
Localized and propagating surface plasmon resonances are known to show very pronounced interactions if they are simultaneously excited in the same nanostructure. Here, we study the Fano interference that occurs between localized surface plasmon resonance (LSPR) and propagating surface plasmon polariton (SPP) modes by means of phase-sensitive spectroscopic ellipsometry. The sample structures consist of periodic gratings of gold nanodisks on top of a continuous gold layer and a thin dielectric spacer, in which the structural dimensions were tuned in such a way that the dipolar LSPR mode and the propagating SPP modes are excited in the same spectral region. We observe pronounced anti-crossing and strongly asymmetric line shapes when both modes move to each other’s vicinity, accompanied of largely increased phase differences between the respective plasmon resonances. Moreover, we show that the anti-crossing can be exploited to increase the refractive index sensitivity of the localized modes dramatically, which result in largely increased values for the figure-of-merit which reaches values between 24 and 58 for the respective plasmon modes. 相似文献
150.
Willem Bintig Judith Baumgart Wilhelm J. Walter Alexander Heisterkamp Holger Lubatschowski Anaclet Ngezahayo 《Journal of bioenergetics and biomembranes》2009,41(1):85-94
Purinergic signalling in rat GFSHR-17 granulosa cells was characterised by Ca2+-imaging and perforated patch-clamp. We observed a resting intracellular Ca2+-concentration ([Ca2+]i) of 100 nM and a membrane potential of −40 mV. This was consistent with high K+− and Cl− permeability and a high intracellular Cl− concentration of 40 mM. Application of ATP for 5–15 s every 3 min induced repeated [Ca2+]i increases and a 30 mV hyperpolarization. The phospholipase C inhibitor U73122 or the IP3-receptor antagonist 2-aminoethoethyl diphenyl borate suppressed ATP responses. Further biochemical and pharmacological experiments
revealed that ATP responses were related to stimulation of P2Y2 and P2Y4 receptors and that the [Ca2+]i increase was a prerequisite for hyperpolarization. Inhibitors of Ca2+-activated channels or K+ channels did not affect the ATP-evoked responses. Conversely, inhibitors of Cl− channels hyperpolarized cells to −70 mV and suppressed further ATP-evoked hyperpolarization. We propose that P2Y2 and P2Y4 receptors in granulosa cells modulate Cl− permeability by regulating Ca2+-release. 相似文献