bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sphingomyelins suppress the targeted disruption of lysosomes/endosomes by the photosensitizer NPe6 during photodynamic therapy
Authors: Caruso Joseph A. , Mathieu Patricia A. , Reiners John J. 
Published: December 2005

Recent studies have described a biochemical pathway whereby lysosome disruption and the released proteases initiate the intrinsic apoptotic pathway. Irradiation of murine hepatoma 1c1c7 cells preloaded with the lysosomal photosensitizer NPe6 (N-aspartyl chlorin e6) caused a rapid loss of Acridine Orange staining of acidic organelles, release of cathepsin D from late endosomes/lysosomes and the activation of procaspase-3. Pretreatment of NPe6-loaded cultures with 10–50 μM 3-O-MeSM (3-O-methylsphingomyelin) caused a concentration-dependent suppression of apoptosis following irradiation. This suppression reflected a stabilization of lysosomes/endosomes, as opposed to an inhibition of the accumulation of photosensitizer in these organelles. Exogenously added sphingomyelin, at comparable concentrations, offered some protection, but less than 3-O-MeSM. Fluorescence microscopy showed that 3-O-MeSM competed with NBD-C6-sphingomyelin (6-{[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]hexanoyl} sphingosyl phosphocholine) for co-localization with LysoTracker Red in acidic organelles. Pre-treatment of 1c1c7 cultures with 3-O-MeSM also suppressed the induction of apoptosis by TNFα (tumour necrosis factor α), but offered no protection against HA14-1 [ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate], staurosporine, tunicamycin or thapsigargin. These results suggest that exogenously added 3-O-MeSM is trafficked to and stabilizes late endosomes/lysosomes against oxidant-induced damage, and further implicate a role for lysosomal proteases in the apoptotic processes initiated by TNFα and lysosomal photosensitizers.
Distinct structure and activity recoveries reveal differences in metal binding between mammalian and Escherichia coli alkaline phosphatases
Authors: Zhang Le , Buchet René , Azzar Gérard 
Published: December 2005

The amino acids involved in the coordination of two Zn2+ ions and one Mg2+ ion in the active site are well conserved from EAP (Escherichia coli alkaline phosphatase) to BIAP (bovine intestinal alkaline phosphatase), whereas most of their surrounding residues are different. To verify the consequences of this heterology on their specific activities, we compared the activity and structure recoveries of the metal-free forms (apo) of EAP and of BIAP. In the present study, we found that although the sensitivities of EAP and BIAP to ions remained similar, significant differences in dimeric structure stability of apo-enzymes were observed between EAP and BIAP, as well as in the kinetics of their activity and secondary structure recoveries. After mild chelation inactive apo-EAP was monomeric under mild denaturing conditions, whereas inactive apo-BIAP remained dimeric, indicating that the monomer–monomer contact was stronger in the mammalian enzyme. Dimeric apo-EAP (0.45 μM, corresponding to 4 units/ml) recovered approx. 80% of its initial activity after 3 min incubation in an optimal recovery medium containing 5 μM Zn2+ and 5 mM Mg2+, whereas dimeric apo-BIAP (0.016 μM, corresponding to 4 units/ml) recovered 80% of its native activity after 6 h incubation in an optimal recovery medium containing 0.5 μM Zn2+ and 5 mM Mg2+. Small and different secondary structure changes were also observed during activity recoveries of apo-BIAP and apo-EAP, which were not in parallel with the activity recoveries, suggesting that distinct and subtle structural changes are required for their optimal activity recoveries.
Promiscuous interaction of SNAP-25 with all plasma membrane syntaxins in a neuroendocrine cell
Authors: Bajohrs Mark , Darios Frédéric , Peak-Chew Sew-Yeu , Davletov Bazbek 
Published: December 2005

SNAP-25 (25 kDa synaptosome-associated protein) is found in cells that release neurotransmitters and hormones, and plays a central role in the fusion of secretory vesicles with the plasma membrane. SNAP-25 has been shown to interact specifically with syntaxin 1, a 35 kDa membrane protein, to mediate the fusion process. Here, we investigated whether other known syntaxin isoforms found at the plasma membrane can serve as binding partners for SNAP-25 in vivo. In our analysis, we employed rat phaeochromocytoma PC12 cells that are often used as a model of neuronal functions. We now show that these cells contain large amounts of SNAP-25, which interacts not only with syntaxin 1, but also with ubiquitous syntaxins 2, 3 and 4. The plasma membrane syntaxins appear to occupy complementary domains at the plasma membrane. In defined reactions, the ubiquitous plasma membrane syntaxin isoforms, when in binary complexes with SNAP-25, readily bound vesicular synaptobrevin to form SDS-resistant SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) complexes implicated in membrane fusion. However, vesicular synaptotagmin and cytosolic complexin, both implicated in the fusion process, exhibited differential ability to interact with the SNARE complexes formed by syntaxins 1–4, suggesting that the plasma membrane syntaxins may mediate vesicle fusion events with different properties.
Evolution of the acyl-CoA binding protein (ACBP)
Authors: Burton Mark , Rose Timothy M. , Færgeman Nils J. , Knudsen Jens 
Published: December 2005

Acyl-CoA-binding protein (ACBP) is a 10 kDa protein that binds C12–C22 acyl-CoA esters with high affinity. In vitro and in vivo experiments suggest that it is involved in multiple cellular tasks including modulation of fatty acid biosynthesis, enzyme regulation, regulation of the intracellular acyl-CoA pool size, donation of acyl-CoA esters for β-oxidation, vesicular trafficking, complex lipid synthesis and gene regulation. In the present study, we delineate the evolutionary history of ACBP to get a complete picture of its evolution and distribution among species. ACBP homologues were identified in all four eukaryotic kingdoms, Animalia, Plantae, Fungi and Protista, and eleven eubacterial species. ACBP homologues were not detected in any other known bacterial species, or in archaea. Nearly all of the ACBP-containing bacteria are pathogenic to plants or animals, suggesting that an ACBP gene could have been acquired from a eukaryotic host by horizontal gene transfer. Many bacterial, fungal and higher eukaryotic species only harbour a single ACBP homologue. However, a number of species, ranging from protozoa to vertebrates, have evolved two to six lineage-specific paralogues through gene duplication and/or retrotransposition events. The ACBP protein is highly conserved across phylums, and the majority of ACBP genes are subjected to strong purifying selection. Experimental evidence indicates that the function of ACBP has been conserved from yeast to humans and that the multiple lineage-specific paralogues have evolved altered functions. The appearance of ACBP very early on in evolution points towards a fundamental role of ACBP in acyl-CoA metabolism, including ceramide synthesis and in signalling.
Recombinant prion protein does not possess SOD-1 activity
Authors: Jones Samantha , Batchelor Mark , Bhelt Daljit , Clarke Anthony R. , Collinge John , Jackson Graham S. 
Published: December 2005

A considerable body of evidence now shows that PrP (prion protein) binds metal ions with high affinity and it has been claimed that the binding of copper (II) ions to PrP confers SOD (superoxide dismutase) activity. In turn, it has been suggested that PrP is a synaptic dismutase and that loss of this function, as a result of the conversion of PrPC into PrPSc, results in pathology and hence morbidity associated with prion disease. However, contrary to previous reports, in the present study we have found that PrP exhibits no detectable dismutase activity above baseline levels measured for copper (II) ions in water when assayed using a reliable procedure with a detection limit of at least 2 units of activity/mg of protein. This was true when the assay was performed with either PrP refolded from a denatured state in the presence of copper, as in previous studies, or native PrP loaded with copper. Thus if PrP has any role in oxidative stress, it must be indirect as a regulator of protective cellular responses.
Varying the heart rate response to dynamic exercise in pacemaker-dependent subjects: effects on cardiac output and cerebral blood velocity
Authors: Bogert Lysander W. J. , Erol-Yilmaz Ayten , Tukkie Raymond , Van Lieshout Johannes J. 
Published: December 2005

Cerebral blood flow increases upon the transition from rest to moderate exercise, but becomes affected when the ability to raise CO (cardiac output) is limited. HR (heart rate) is considered to contribute significantly to the increase in CO in the early stages of dynamic exercise. The aim of the present study was to test whether manipulation of the HR response in patients dependent on permanent rate-responsive ventricular pacing contributes to the increase in CO, MCA Vmean [mean MCA (middle cerebral artery) velocity] and work capacity during exercise. The effect of setting the pacemaker to DSS (‘default’ sensor setting) compared with OSS (‘optimized’ sensor setting) on blood pressure, CO, SV (stroke volume) and MCA Vmean was evaluated during ergometry cycling. From rest to exercise at 75 W, the rise in HR in OSS [from 73 (65–87) to 116 (73–152) beats/min; P&lt;0.05] compared with DSS [70 (60–76) to 97 (67–117) beats/min; P&lt;0.05] was larger. There was an increase in SV during exercise with DSS, but not with OSS, such that, at all workloads, SVs were greater during DSS than OSS. The slope of the HR–CO relationship was larger with DSS than OSS (P&lt;0.05). From rest to exercise, MCA Vsys (systolic MCA velocity) increased in OSS and DSS, and MCA Vdias (diastolic MCA velocity) was reduced with DSS. No changes were observed in MCA Vmean. Manipulation of the pacemaker setting had no effect on the maximal workload [133 (100–225) W in OSS compared with 129 (75–200) W in DSS]. The results indicate that, in pacemaker-dependent subjects with complete heart block and preserved myocardial function, enhancing the HR response to exercise neither augments CO by a proportional offset of the exercise-induced increase in SV nor improves cerebral perfusion.
13C- and 2H-labelled glucose compared for minimal model estimates of glucose metabolism in man
Authors: Bluck Leslie J. C. , Clapperton Allan T. , Coward W. Andy 
Published: December 2005

In the present study, we have investigated the use of 1-[13C]glucose and GC/combustion/isotope-ratio MS as an alternative to 6,6-[2H2]glucose and GC/MS in the determination of parameters of glucose metabolism using the IVGTT (intravenous glucose tolerance test) interpreted by labelled (hot) minimal models. The study has been done in four populations, normoglycaemics (subdivided into lean and obese individuals), subjects with impaired glucose tolerance and those with diabetes mellitus. Although the use of carbon label may in some circumstances be compromised by substrate recycling, our hypothesis was that this would not be an issue under the condition of suppression of hepatic glucose production during the short timescale of an IVGTT. In all four groups, we found that the methodology employing the carbon label gave equivalent results to those obtained using the conventional deuterated material, but the sensitivity of the measurement technique in the new approach was sufficient to allow an approx. 15-fold reduction in the quantity of isotope administered. In addition to the clear cost advantages, this represents a significant scientific advance in that true tracer status is more nearly attained in these measurements with near-physiological tracee loads.
Exercise and youth: Physical activity,sport involvement, and development
Authors: Wigger Ulrike 
Published: December 2005

This article summarizes Plenary Session I, “Exercise and Youth,” at the 6th Annual Congress of the European College of Sport Science (Cologne, 24–28 July 2001). The session provided a broad overview of current knowledge and progress in the field. Using the results of cross‐sectional studies, Dietrich Kurz of Germany demonstrated associations between sport activity and personal attributes of psychosocial and physical health. Using the results of a longitudinal study, Wolf‐Dietrich Brettschneider found that German sport clubs in and of themselves do not have significant effects on the development of psychosocial health in young people. In a Dutch longitudinal study, Willem van Mechelen found moderate tracking of biological cardiovascular risk factors and of physical fitness from adolescence into adulthood, as well as relationships between adolescent physical activity and both adult bone health and maximal aerobic power. Reporting on findings from U.S.‐American school intervention program, Tom McKenzie demonstrated the importance of social contexts, physical opportunities for sport, mental motivation for healthy lifestyles, trainer and teacher development with continuous education, and innovative, cooperative arrangements between schools and community‐based agencies.
The mediating role of self‐determination in the relationship between goal orientations and physical self‐worth in greek exercisers
Authors: Georgiadis Manolis , Biddle Stuart , Chatzisarantis Nikos 
Published: December 2005

This paper examines correlates of physical self‐worth (PSW) in exercisers through employing two theoretical constructs popular in motivational psychology. Selfdetermination theory (SDT) and achievement goal orientation theory were adopted, and a cross‐sectional survey was employed. Greek exercisers (N = 350, mean age = 30.8 years), participating in 1 of 4 different exercise activities were studied. Theoretical predictions established a model that was tested through path analysis. The selfdetermination continuum was hypothesized to mediate the relation between goal orientations and PSW. Task orientation predicted PSW through intrinsic motivation and identified regulation and, to a lesser extent, through introjected regulation. Ego orientation was related mainly to extrinsic regulation, and it predicted PSW only through the internally regulated variables of intrinsic and identified regulation. The model was found to fit the data well. Results showed that 17.2% of PSW was explained by the 2 motivational constructs.
The effect of pre‐shot routines on golf wedge shot performance
Authors: McCann Paul , Lavallee David , Lavallee Ruth 
Published: December 2005

The objective of this study was to examine the effect of pre‐performance routines among golfers of low skill and non‐golfers on wedge golf shot performance. The intervention strategies involved a physical skill and cognitive‐behavioral routine program, as well as a physical skills‐only program. Performance was measured on a pre‐intervention test, postintervention test, and following a period of time without treatment, and involved wedge shots being played from distances of 40, 50, and 60 m from a target. Participants in this study (N = 68) were assigned to either a golfer or non‐golfer group. Participants in the treatment groups attended 2 practice sessions per week during the acquisition phase. A variable practice design was incorporated during the intervention phase. Non‐golfers in both intervention groups improved performance following the acquisition phase and maintained these levels of performance in the retention test. Greater improvements in performance were found in the non‐golfer physical skills and cognitive‐behavioral routine group. The non‐golfer physical skills and cognitive‐behavioral routine group was the only group to realize significant improvements in performance when comparing initial test performance measures to post‐intervention and retention test performance measures across all test distances. Although the golfer treatment groups had consistent improvement in performance measures following the intervention phase, these improvements did not reach statistical significance in the majority of cases.
Correlations of the renin‐angiotensin‐system (RAS) gene polymorphisms with cardiac growth factors endothelin‐1 and angiotensin II in high performance athletes
Authors: Graf Christine , Diet Frank , Palma‐hohmann Isabel , Mahnke Nicole , Böhm Michael , Rost Richard , Predel Hans‐georg 
Published: December 2005

Background: The regulation of myocardial mass in athletes involves complex interactions between physical stress, cardiac growth factors (GF), and the individual genetic background. Studies suggest the renin‐angiotensin‐system (RAS) plays a key role in the development of myocardial hypertrophy. Genetic polymorphisms of the RAS, associated with an activation, have been shown to correlate with left ventricular mass (LVM) in athletes. It is not clear whether these polymorphisms influence angiotensin (A) II levels directly or only markers coprecipitating with other factors modifying LVM. Endothelin (ET)‐1 acts synergistically to AII in the induction of cardiac hypertrophy. The role of these GF in an athlete's heart is not yet clarified. Objectives: To analyze the correlation of RAS‐gene polymorphisms with AII and ET‐1 plasma concentrations in high performance athletes. Methods: In 83 male Caucasian, mainly endurance trained, elite athletes, intensity and duration of exercise were assessed by questionnaires; LVM was determined by 2‐dimensional echocardiography. Plasma concentrations of AII and ET‐1 were determined by radioimmunoassay. Results: LV/VMi significantly above reported average levels in sedentary persons was observed. AII plasma restingconcentrations correlated with the ACE gene polymorphism (p =. 039), finding the highest levels in DD‐athletes. There were no further correlations between the AII levels and the angiotensinogen gene polymorphisms, and the combined polymorphisms (p =.585, p =. 162). ET‐1 plasma levels did not correlate with any of the investigated parameters. No GF correlates with LV/VMi. Conclusions: The highest AII plasma resting concentrations were found in athletes homozygous to DD. This finding suggests a functional effect of the ACE I/D genotypes, possibly influencing cardiac growth in high performance athletes. The absence of a correlation with ET‐1 plasma levels does not rule out its influence; local cardiac effects remain elusive. Further longitudinal studies under controlled exercise conditions are necessary.
Modeling and prediction of competitive performance in swimming upon neural networks
Authors: Edelmann‐nusser Jürgen , Hohmann Andreas , Henneberg Bernd 
Published: December 2005

The purpose of the paper is to demonstrate that the performance of an elite female swimmer in the finals of the 200‐m backstroke at the Olympic Games 2000 in Sydney can be predicted by means of the nonlinear mathematical method of artificial neural networks (Multi‐Layer Perceptrons). The data con‐sisted of the performance output of 19 competitions (200‐m backstroke) prior to the Olympics and the training input data of the last 4 weeks prior to each competition. Multi‐Layer Perceptrons with 10 input neurons, 2 hidden neuron, and 1 output neuron were used. Since the data of 19 competitions are insuffi‐cient to train such networks, the training input and competition data of another athlete were used in the training processes of the neural networks to pre‐train the neural networks. The neural models were validated by the “leave‐one‐out”; method, then the neural models were used to predict the Olympic competitive performance. The results show that the modeling was very precise; the error of the prediction was only 0.05 s, with a total swim time of 2:12.64 min:s.
Contribution of vitamin D receptor genotypes to bone mineral density in young male athletes with different impact loading
Authors: Nakamura Orie , Ishii Tomoo , Mankyu Hirotoshi , Tsubakimoto Shozo , Nomura Takeo , Tokuyama Kumpei 
Published: December 2005

Bone adaptation to exercise relies on exposures to impact loading in sports, but the ability of skeletal change seems to be highly variable among individuals. The present study was designed to investigate the association between a poly‐morphism in the vitamin D receptor (VDR) gene at the translation initiation site and impact loading on bone mineral density (BMD). Analysis of the VDR genotypes detected by endonuclease FokI (FF, Ff, and ff) and measurement of total body BMD (TBMD) were performed in 212 young males; 84 athletes were involved in weight‐bearing sports, 48 in competitive swimming, and 80 non‐athletic controls. The differences in TBMD between athletes and controls de‐pended on the VDR genotypes; enhanced BMD in weight‐bearing athletes was found in FF (7.7%, p
Using ratings of perceived exertionto reproduce blood lactate levels duringa continuous exercise bout of varying intensities
Authors: Misic Mark , Plowman Sharon , Wiese Christine 
Published: December 2005

The purpose of this study was to investigate whether blood lactate concentra‐tion (BLC) could be reproduced, corresponding to previously measured BLC, by using Borg's rate of perceived exertion (RPE) scale to determine exercise intensity at 3 different levels during a single 30‐min exercise bout. Twelve participants (4 M, 8 F; age: 26.5 ± 3.7 years; height: 168.9 ± 8.3 cm; weight: 68.2 ± 14.1 kg) completed an RPE estimation trial (a 3‐min stage incremental treadmill protocol to volitional fatigue, where RPE was noted at each stage); practiced running at the workloads corresponding to their RPE of 11, 14, and 16; and, within 2 weeks after the practice run, completed a continuous, self‐selected intensity run for 10‐min at each RPE target value (the production run). Paired t tests indicated that there were no significant difference (p >. 05) in BLC between the estimation and production trials at RPE of 11, 14, and 16 (estima‐tion trial 2.71 ± 0.83, 4.15 ± 1.78, 5.83 ± 2.09 mM, production trial 2.99 ± 1.18, 4.32 ± 2.09, 5.62 ± 1.90 mM), indicating as a group that subjects were able to successfully reproduce target BLC. There was, however, considerable intra‐and inter‐subject variability that warrants additional investigation before these results can be used to support RPE as a production tool for target BLC.