bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human brain synembryn interacts with Gsα and Gqα and is translocated to the plasma membrane in response to isoproterenol and carbachol
Authors: Klattenhoff Carla , Montecino Martín , Soto Ximena , Guzmán Leonardo , Romo Ximena , de los Angeles García María , Mellstrom Britt , Naranjo José Ramón , Hinrichs María Victoria , Olate Juan 
Published: March 2003

AbstractHeterotrimeric G‐proteins transduce signals from heptahelical transmembrane receptors to different effector systems, regulating diverse complex intracellular pathways and functions. In brain, facilitation of depolarization‐induced neurotransmitter release for synaptic transmission is mediated by Gsα and Gqα. To identify effectors for Gα‐proteins, we performed a yeast two‐hybrid screening of a human brain cDNA library, using the human Gαs protein as a bait. We identified a protein member of the synembryn family as one of the interacting proteins. Extending the study to other Gα subunits, we found that Gqα also interacts with synembryn, and these interactions were confirmed by in vitro pull down studies and by in vivo confocal laser microscopy analysis. Furthermore, synembryn was shown to translocate to the plasma membrane in response to carbachol and isoproterenol. This study supports recent findings in C. elegans where, through genetic studies, synembryn was shown to act together with Gqα regulating neuronal transmitter release. Based on these observations, we propose that synembryn is playing a similar role in human neuronal cells. © 2003 Wiley‐Liss, Inc.
Mouse epidermal stem cells proceed through the cell cycle
Authors: Dunnwald Martine , Chinnathambi Sathivel , Alexandrunas Dana , Bickenbach Jackie R. 
Published: March 2003

AbstractThe epidermis is a continuously renewing tissue maintained by undifferentiated stem cells. For decades it has been assumed that epidermal stem cells (ESCs) were held in the G0 phase of the cell cycle and that they only entered the cell cycle when needed. Previously, we showed that ESCs retained nuclear label for long periods, indicating that these cells did not proceed through the cell cycle at the same rate as the other proliferative basal cells. However, their exact cell‐cycle profile has not been determined because a pure population of ESCs has not been available. In this study, we sorted stem and transient amplifying (TA) cells from murine neonatal back skin, and adult ear, footpad, and back skin, using our recently developed method. We found that neonatal back skin had two times the number of ESCs as the adult tissues. Despite the age and anatomical difference, these ESC populations exhibited similar cell cycle profiles with approximately 96% in G0/G1 and 4% in S‐G2/M. The cell cycle profiles of the TA cells from neonatal back skin and adult footpad also showed a profile similar to each other (85% in G1 and 15% in S‐G2/M). Examination of genes on a cell cycle chip showed that proliferation associated genes and only p57 were upregulated in the TA cell and ESC population, respectively. We found BrdU positive and cyclin B1 positive cells in all groups, confirming that both ESCs and TA cells were cycling. These data demonstrate that there are more TA cells dividing than ESCs, that the cell cycle profile of adult TA cells is related to the proliferative state of the tissue in which they reside, and that ESC proceed through the cell cycle. © 2003 Wiley‐Liss, Inc.
Compartmental fasciotomy and isolating a muscle from neighboring muscles interfere with myofascial force transmission within the rat anterior crural compartment
Authors: Huijing Peter A. , Maas Huub , Baan Guus C. 
Published: March 2003

AbstractMuscles within the anterior crural compartment (extensor digitorum longus, EDL; tibialis anterior, TA; and extensor hallucis longus, EHL) and within the peroneal compartment were excited simultaneously and maximally. All muscles were kept at constant length with the exception of EDL, for which muscle length was changed by moving its proximal tendon. Active and passive force was measured at proximal as well as distal EDL tendons and at the combined distal tendons of TA and EHL (TA+EHL). In the initial experimental condition, a difference (Fproximal > Fdistal) in EDL force, amounting to 0–14% of proximal force, was confirmed for most EDL lengths. This is interpreted as a clear proof of extramuscular myofascial force transmission, as no significant EDL length effects could be shown on TA+EHL force. Repeated measurements were confirmed to cause marked changes of both proximal and distal length–force characteristics, such as a shift of the whole ascending limb of the active curve, including optimum length, to higher lengths without decreasing optimum force, and decreasing active force at low lengths (by ∼57%). Repeated measurements also lowered proximal and distal EDL passive force (by up to 35%). The proximo–distal difference in passive as well as active EDL force was decreased, but persisted. At most lengths, this difference for active force amounted to a constant fraction (14%) of proximal force. TA+EHL force was not affected significantly. Subsequently, acute effects of experimental surgical alterations were studied: The first manipulation was full lateral fasciotomy of the anterior crural compartment that caused a further decrease in active force at the proximal EDL but not at the distal EDL tendon. Passive forces showed no further significant changes. The proximo–distal EDL active force difference decreased to 0–5% of proximal force. After fasciotomy, TA+EHL force increased by 30%. This was interpreted as evidence of increased intramuscular and decreased extramuscular myofascial force transmission. The second manipulation was full isolation of EDL from TA+EHL, but not from extramuscular connective tissues, which caused a further decrease of the EDL proximo–distal force differences, indicating a stiffening effect of the presence of TA+EHL on the extramuscular matrix. For EDL active force the difference was no longer significantly different from zero. In contrast, for EDL passive force the proximo–distal force difference persisted. It is concluded that extramuscular myofascial force transmission is an important feature of the anterior crural compartment. The magnitude of this force transmission requires that it be considered in analysis of muscular function. J. Morphol. 256:306–321 2003 ©2003 Wiley‐Liss, Inc.
Stomach of Aplysia depilans (Mollusca, Opisthobranchia): A histochemical, ultrastructural, and cytochemical study
Authors: Lobo‐da‐Cunha Alexandre , Batista‐Pinto Carla 
Published: March 2003

AbstractWe report the results of a morphological, histochemical, and cytochemical characterization of the Aplysia depilans stomach, an organ little studied in opisthobranchs. Very thin ciliated cells with microvilli on their apical surfaces are predominant in the epithelium lining the lumen of the stomach. Many lysosomes with a strong arylsulphatase activity were present in the apical regions of these cells that could also contain some lipid droplets and glycogen. Small peroxisomes were observed, usually around lipid droplets or mitochondria. Bottle‐shaped secretory cells are very common in this epithelium and produce a secretion rich in proteins and acidic mucopolysaccharides. Most of the cytoplasm of these mucus‐producing cells was filled with a very high number of granules and the nucleus is dislocated to the basal region. Cisternae of rough endoplasmic reticulum were abundant around the nucleus and several Golgi stacks were also present in this area. In spite of the variation in the electron density of the granules, only one type of secretory cell seems to be present in the stomach epithelium, since granules with very different electron densities were frequently found in the same cell. A few neurons were also found in the stomach epithelium of this species. Fibrocytes, muscle cells, nerves, and amebocytes were observed in the connective tissue of the stomach wall. J. Morphol. 256:360–370, 2003. © 2003 Wiley‐Liss, Inc.
Guidelines for using quantitative magnetization transfer magnetic resonance imaging for monitoring treatment of multiple sclerosis
Authors: Horsfield Mark A. , Barker Gareth J. , Barkhof Frederik , Miller David H. , Thompson Alan J. , Filippi Massimo 
Published: March 2003

AbstractQuantitative evaluation of brain magnetic resonance imaging (MRI) scans is now an accepted part of the trial of new putative treatments for multiple sclerosis (MS). However, conventional MRI is not pathologically specific, and it does not reveal the details of the pathological processes that underlie the progression of the disease. Magnetization transfer (MT) imaging is a relatively new quantitative technique that appears to offer some pathological specificity, and can be used to monitor the changes over time in both individual lesions and the central nervous system as a whole. This paper considers the case for incorporating MT imaging into new clinical trials, so that the utility of MT for monitoring the modification of MS progression by treatment can be assessed. Specific guidelines for implementing MT imaging as part of a large multicenter clinical trial are given, and practical considerations when planning such a trial are detailed. It is anticipated that MT imaging will be incorporated into many new trials in the near future. J. Magn. Reson. Imaging 2003;17:389–397. © 2003 Wiley‐Liss, Inc.
MRI depiction of chronic intradural (subdural) hematoma in evolution
Authors: Atkinson John L.D. , Lane John I. , Aksamit Allen J. 
Published: March 2003

AbstractThe usual chronic subdural hematoma encountered in the elderly is actually thought to be a chronic intradural hematoma, which has been described clinically and anatomically. However, the evolution of how this chronic hematoma occurs remains enigmatic. We report the first magnetic resonance (MR) depiction of an apparent chronic intradural hematoma in evolution over several months in a 61‐year‐old man after a minimal head injury. The time delay from injury, subsequent focal pachymeningeal T1‐gadolinium enhancement, and apparent splitting of the pachymeninges by proven chronic hematoma should serve as a stimulus for further MR investigations of this interesting process. J. Magn. Reson. Imaging 2003;17:484–486. © 2003 Wiley‐Liss, Inc.
Investigation of apparent diffusion constant as an indicator of early degenerative disease in articular cartilage
Authors: Mlynárik Vladimír , Sulzbacher Irene , Bittšanský Michal , Fuiko Reinhard , Trattnig Siegfried 
Published: March 2003

AbstractPurposeTo investigate the apparent diffusion constant (ADC) as a prospective magnetic resonance imaging (MRI) marker of early degeneration in articular cartilage.Materials and MethodsEarly degenerative changes were studied using in vitro MRI on cartilage‐bone specimens excised from human femoral condyles. The loss of proteoglycans developed in vivo due to a degenerative process was compared with a gadolinium diethylenetriamine pentaacetate anion (Gd‐DTPA2–) enhanced decrease of T1 relaxation times, and with an increase of ADCs and T2 relaxation times.ResultsContrast enhanced T1 values decreased and the diffusion constants increased in cartilage regions with depleted proteoglycans. The relative changes in diffusion constants were smaller than those of Gd‐DTPA2– enhanced T1, and in some proteoglycan‐depleted regions no changes in the diffusion constants were detected. T2 relaxation times showed considerable spatial variability that did not correlate with proteoglycan concentration.ConclusionIn contrast to Gd‐DTPA2– enhanced T1, which reflects changes in chemical composition, diffusion constants may reflect structural degradation of the cartilage matrix. J. Magn. Reson. Imaging 2003;17:440–444. © 2003 Wiley‐Liss, Inc.
Assessment of reliability in functional imaging studies
Authors: Specht Karsten , Willmes Klaus , Shah N. Jon , Jäncke Lutz 
Published: March 2003

AbstractPurposeTo investigate the reliability of functional magnetic resonance imaging (fMRI), an approach for mapping and quantifying reliably activated voxels was developed.Materials and MethodsFirst, a SPM99 analysis was performed, and the resulting statistical maps were taken as the basis for subsequent analyses of reliability. Several approaches were demonstrated using 1) a voxel‐wise intraclass correlation coefficient (ICC); 2) an analysis of scatter plots, calculating the correlation of contrast t‐values for pairs of activation maps; and 3) the ratio of overlapping volumes as suggested in the literature. The methods were applied to an fMRI study in which subjects were asked to vary their attentional effort during watching a flickering checkerboard pattern with varying letters in the center. The subjects had to ignore or attend to the presentation, or they had to detect a target letter within the checkerboard.ResultsThe imaging data showed good reliability in terms of ICC for regions of visual processing, as well as for frontal areas, especially in the letter detection task. Furthermore, the size of reliable clusters depended on the presumed attentional effort of the subjects.ConclusionApplication of the method demonstrated that the activation due to visual stimulation could also be detected very consistently during a no‐attend condition, but the reliability of the activations were best during the attended tasks. J. Magn. Reson. Imaging 2003;17:463–471. © 2003 Wiley‐Liss, Inc.
Multislice double inversion‐recovery black‐blood imaging with simultaneous slice reinversion
Authors: Yarnykh Vasily L. , Yuan Chun 
Published: March 2003

AbstractPurposeTo develop a technique for time‐efficient multislice double inversion‐recovery (DIR) black‐blood imaging and to test its applicability and limitations for high‐resolution imaging of carotid arteries.Materials and MethodsA multislice DIR pulse sequence with fast spin‐echo (FSE) readout was implemented on a 1.5T magnetic resonance (MR) scanner. The principle of the method is that a slice‐selective inversion in a DIR preparation reinverts an entire slice pack, and all slices are imaged within repetition time (TR). The number of slices acquired per TR (N) controls the inversion time (TI) to execute the readout for each slice at the zero‐crossing point of blood. Multislice DIR images (TR/TE = 2500/9 msec) of carotid arteries were obtained with variable N = 2–8 from four subjects. The method was compared with the standard single‐slice DIR and inflow saturation techniques.ResultsMultislice DIR with N = 2–6 provided similar flow suppression in carotid arteries as single‐slice DIR. At all N = 1–8, blood suppression by DIR was significantly better than by inflow saturation. An additional limitation of multislice DIR was saturation of the signal from stationary tissues that worsened visualization of the vessel wall at N ≥ 6.ConclusionMultislice DIR provides up to eight‐fold improvement of time‐efficiency relative to single‐slice DIR and high‐quality blood suppression. J. Magn. Reson. Imaging 2003;17:478–483. © 2003 Wiley‐Liss, Inc.
Effects of the North Atlantic oscillation on the probability for climatic categories of local monthly rainfall in southern Spain
Authors: Muñoz‐Díaz D. , Rodrigo F. S. 
Published: March 2003

AbstractIn many regions of the world, planning agricultural and water management activities is usually done based on probabilities for seasonal or monthly rainfall, for specified intervals of values. These intervals of rainfall amounts are commonly grouped into three categories: drought, normal rainfall, and abundant rainfall. Changes in the probabilities of occurrence of rainfall amounts within these climatic rainfall categories will influence the decisions that farmers and water managers will take. This research explores the changes produced by the North Atlantic oscillation (NAO) on the probability that local monthly rainfall takes in the southern Iberian Peninsula. The evolution of the NAO was divided into three phases: negative NAO, ‘normal’ NAO, and positive NAO, and local rainfall series were divided into three groups, corresponding to each NAO phase. The resulting empirical distribution functions were analysed and modelled by Gamma distributions. The results allow one to estimate the change in the probabilities of wet and dry months when a change in NAO phase is produced. The main result of this work is that changes in the probability of occurrence of climate categories of rainfall are more complex than only an increase of rainfall amount during the negative NAO phase and a decrease during the positive NAO phase. In fact, a certain asymmetry is detected in January, with more extremes linked to the negative NAO phase. Copyright © 2003 Royal Meteorological Society
The ‘Montserrat‐2000’ flash‐flood event: a comparison with the floods that have occurred in the northeastern Iberian Peninsula since the 14th century
Authors: Llasat María del Carmen , Rigo Tomeu , Barriendos Mariano 
Published: March 2003

AbstractThis paper presents an analysis of the flash floods that occurred in Catalonia (NE Iberian Peninsula) on 10 June 2000, in the context of the historical floods recorded since the 14th century. The study starts with pluviometric and meteorological analyses (essentially synoptic and thermodynamic) of the episode. There follows a comparison of this event with previous floods for which we have instrumental information, information from archives, or both types of information. In some cases this permitted us to make a meteorological comparison of episodes similar to that of June 2000, and the complete series was used to carry out a frequency analysis of floods that have occurred in the basin under study. The conclusions show that although catastrophic flooding in spring is not as typical a phenomenon as autumn flooding, such floods have been recorded at least once each century, and it can be stated that the synoptic meteorological situation, where recorded, showed similar characteristics in all cases. Copyright © 2003 Royal Meteorological Society
Preferential flow and aging of NAPL in the unsaturated soil zone of a hazardous waste site: implications for contaminant transport
Authors: Totsche Kai U. , Kögel‐Knabner Ingrid , Haas Bettina , Geisen Stefan , Scheibke Rainer 
Published: March 2003

AbstractFlow of non‐aqueous phase liquids (NAPL) in the unsaturated zone is thought to be driven by gravity with a dominant vertical flow direction, and lateral spreading to be limited to the gradient of the relative permeabilities. The effect of soil profile build‐up, preferential flow, aging, and groundwater level fluctuations is mostly neglected. The objective of our study was to check the effects of such processes on the fate of NAPL in the unsaturated soil zone. At a hazardous waste site, we conducted a field survey of the unsaturated soil zone and monitored the groundwater for a two year period. We conducted spatially resolved and depth dependent soil sampling and analysis and the evaluation of former ram and core drilling protocols. The samples were analyzed for the 16 EPA PAH and alkanes with GC‐MS and GC‐FID. 13C‐NMR spectroscopy was used to assess structural changes of the NAPL phase. Flow of bulk NAPL along macropores and along preferential permeability structures, like sedimentation discontinuities, are the dominant transport pathways which cause large lateral spreading beyond those expected by the relative permeability gradient. Accumulation of NAPL was found at locations with abrupt textural changes and within the zone of capillary rise. Aging of NAPL results in the depletion in soluble and volatile compounds but also in oxidation and polymerization. It increases the chemical diversity and decreases the mobility of the NAPL. Thus, NAPL flow ceases much earlier than expected from the capillary forces. As chemical transformation is restricted to the NAPL water/air interface, a skin‐like thin film is formed which encapsulates and preserves the bulk NAPL from further hardening, limiting contaminant mass transfer from the NAPL to the aqueous phase.
Estimating water retention curves of forest soils from soil texture and bulk density
Authors: Teepe Robert , Dilling Hermann , Beese Friedrich 
Published: March 2003

AbstractForest soils differ significantly from the arable land in their distribution of the soil bulk density and humus content, but the water retention parameters are primarily derived from the data of agricultural soils. Thus, there is a need to relate physical parameters of forest soils with their water retention characteristics and compare them with those of agricultural soils. Using 1850 water retention curves from forest soils, we related the following soil physical parameters to soil texture, bulk density, and C content: air capacity (AC), available water capacity (AWC), and the permanent wilting point (PWP). The ACs of forest soils were significantly higher than those of agricultural soils which were related to the low bulk densities of the forest soils, whereas differences in AWCs were small. Therefore, for a proper evaluation of the water retention curves (WRCs) and the parameters derived from them, further subdivisions of the lowest (< 1.45 g cm‐3) of the three bulk density classes was undertaken to the wide range of low soil densities in forest soils (giving a total of 5 bulk density classes). In Germany, 31 soil texture classes are used for the estimation of soil physical parameters. Such a detailed classification is not required because of insignificant differences in WRCs for a large number of these classes. Based on cluster analysis of AC, AWC, and PWP parameters, 10 texture collectives were obtained. Using 5 classes of bulk densities, we further calculated the ACs, AWCs, and the PWPs for these 10 classes. Furthermore, “van Genuchten parameters” (θ r, θ s, α, and n) were derived which described the average WRC for each designated class. In a second approach using multiple regression analysis, regression functions for AC, AWC, and PWP and for the van Genuchten parameter were calculated.
Organische Substanz und Benetzbarkeit von Bodenproben ‐ eine Interpretation
Authors: Ellies Achim , Hartge Karl Heinrich , MacDonald Roberto , Ramirez Carlos 
Published: March 2003

AbstractAn je vier Standorten vulkanischer oder Anteile vulkanischer Aschen enthaltender Böden unter Wald‐ und unterWeidenutzung wurden aus den A‐Horizonten Aggregate mit 4—6 und 10—12 mm Größe entnommen und durch Schälen in die Bereiche Kern und Schale aufgeteilt. Mit der ausgesiebten Fraktion 38—63 μm wurden auf Objektträgern Körnerpräparate hergestellt und die Benetzungswinkel mit Tropfen gesättigter KCl‐Lösung gemessen. An allen Gruppen wurde der Anteil an organischer Substanz bestimmt. Die Benetzungswinkel stiegen stets mit zunehmendem Anteil an organischer Substanz, unabhängig von der Art der Aufteilung in Gruppen (Nutzung, Alter und Anteil der vulkanischen Mineralkomponente, Aggregatgröße, —bereich und Entnahmetiefe). Die Beziehungen waren auch bei höherer Signifikanz niemals eng (r ∼ 0, 5). Ursachen für die Steigung sind der Mengenanteil separater organischer Partikel sowie Anteile und Ausprägung von Filmen auf Mineralteilchen. Benetzungswinkel in Böden sind Summeneffekte dieser beiden Parameter.