bluuebunny/crossref_metadata_2025_split huggingface dataset:
13C isotopomer analysis of glucose and alanine metabolism reveals cytosolic pyruvate compartmentation as part of energy metabolism in astrocytes
Authors: Zwingmann Claudia , Richter‐Landsberg Christiane , Leibfritz Dieter 
Published: September 2002

AbstractAfter incubation of glial cells with both 13C‐labeled and unlabeled glucose and alanine, 13C isotopomer analysis indicates two cytosolic pyruvate compartments in astrocytes. One pyruvate pool is in an exchange equilibrium with exogenous alanine and preferentially synthesizes releasable lactate. The second pyruvate pool, which is of glycolytic origin, is more closely related to mitochondrial pyruvate, which is oxidized via tri carbonic acid (TCA) cycle activity. In order to provide 2‐oxoglutarate as a substrate for cytosolic alanine aminotransferase, glycolytic activity is increased in the presence of exogenous alanine. Furthermore, in the presence of alanine, glutamate is accumulated in astrocytes without subsequent glutamine synthesis. We suggest that the conversion of alanine to releasable lactate proceeds at the expense of flux of glycolytic pyruvate through lactate dehydrogenase, which is used for ammonia fixation by alanine synthesis in the cytosol and for mitochondrial TCA cycle activity. In addition, an intracellular trafficking occurs between cytosol and mitochondria, by which these two cytosolic pyruvate pools are partly connected. Thus, exogenous alanine modifies astrocytic glucose metabolism for the synthesis of releasable lactate disconnected from glycolysis. The data are discussed in terms of astrocytic energy metabolism and the metabolic trafficking via a putative alanine‐lactate shuttle between astrocytes and neurons. GLIA 34:200–212, 2001. © 2001 Wiley‐Liss, Inc.
Schwann cell myelination occurred without basal lamina formation in laminin α2 chain‐null mutant (dy3K/dy3K) mice
Authors: Nakagawa Masahiro , Miyagoe‐Suzuki Yuko , Ikezoe Koji , Miyata Yuhei , Nonaka Ikuya , Harii Kiyonori , Takeda Shin'Ichi 
Published: September 2002

AbstractThe laminin α2 chain is a major component of basal lamina in both skeletal muscle and the peripheral nervous system. Laminin α2 chain deficiency causes merosin‐deficient congenital muscular dystrophy, which affects not only skeletal muscles, but also the peripheral and central nervous systems. It has been reported that the formation of basal lamina is required for myelination in the peripheral nervous system. In fact, the spinal root of dystrophic mice (dy/dy mice), whose laminin α2 chain expression is greatly reduced, shows lack of basal lamina and clusters of naked axons. To investigate the role of laminin α2 chain and basal lamina in vivo, we examined the peripheral nervous system of dy3K/dy3Kmice, which are null mutants of laminin α2 chain. The results indicate the presence of myelination although Schwann cells lacked basal lamina in the spinal roots of dy3K/dy3K mice, suggesting that basal lamina is not an absolute requirement for myelination in vivo. Immunohistochemically, the expression of laminin α4 chain was increased and laminin α5 chain was preserved in the endoneurium of the spinal root. Laminin α4 and α5 chains may play the critical role in myelination instead of laminin α2 chain in dy3K/dy3Kmice. In addition, the motor conduction velocity of the sciatic nerve was significantly reduced compared with that of wild‐type littermate. This reduction in conduction velocity may be due to small axon diameter, thin myelin sheath and the patchy disruption of the basal lamina of the nodes of Ranvier in dy3K/dy3Kmice. GLIA 35:101–110, 2001. © 2001 Wiley‐Liss, Inc.
Development and validation of the Observation List for early signs of Dementia (OLD)
Authors: Hopman‐Rock Marijke , Tak Erwin C. P. M. , Staats Patricia G. M. 
Published: September 2002

AbstractObjectiveDevelopment and validation of a short Observation List of possible early signs of Dementia (OLD) for use in general practice.DesignStepwise development using reviews of publications and expert consensus. Field study for evaluation of reliability. Validation study (interviews, family forms) using existing valid and reliable measures. Use of data reduction techniques to construct a short version.Setting of field studyTwenty‐two GPs in 19 Dutch practices.ParticipantsThe first two patients seen on 15 working days (n = 470) were observed. Inclusion: age > 75, without a known diagnosis of dementia. Exclusion: psychiatric treatment, severe depression, acute illness with confusion. Division of patients into three groups with no, intermediate, and the most signs (total of interviewed patients, n = 60; family forms, n = 39).Outcome measuresReliability (Cronbach's alpha and factor‐analysis). Convergent validity using the Cognitive Screening Test (CST), the Word Learning Test (WLT, total and retention), the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), the Groningen Activities Restriction Scale (GARS), and an IADL scale. Discriminant validity using the geriatric depression scale (GDS). Construct validity using a Principal Component Analysis (PRINCALS). Incremental validity using the intuitive opinion of the GP (McNemar test).ResultsReliability in the total group 0.88, first factor explained variance 42.5%. Convergent validity (two‐way ANOVA) results: CST (p = 0.00), WLT‐total (p = 0.001), WLT retention (p = 0.00), IQCODE (p = 0.09). No statistically significant differences for GARS and IADL. GDS (p = 0.30) not different. PRINCALS first factor explained 48% of variance. The OLD added to the GP opinion (McNemar p = 0.00). Reliability short version 0.89 (interviewed group), 0.86 (total group).ConclusionsThe OLD is a valid and reliable method to detect early signs of dementia in general practice that can indicate when it may be useful to employ existing screening instruments. Copyright © 2001 John Wiley & Sons, Ltd.
Pharmacotherapy of Alzheimer's disease: is there a need to redefine treatment success?
Authors: Winblad Bengt , Brodaty Henry , Gauthier Serge , Morris John C , Orgogozo Jean‐Marc , Rockwood Kenneth , Schneider Lon , Takeda Masatoshi , Tariot Pierre , Wilkinson David 
Published: September 2002

AbstractThe traditional aim of Alzheimer's disease treatment in clinical trials has been to improve cognitive abilities. It has become increasingly clear, however, that other aspects are important in assessing treatment responses. A group of 10 physicians recently gathered to review the current criteria for assessing treatment success in Alzheimer's disease. While cognition has been previously viewed as the primary measure of efficacy, areas such as functional abilities, behaviour, caregiver burden, quality of life and resource utilization all need to be comprehensively assessed to fully evaluate treatment effects in patients with Alzheimer's disease, as well as their impacts on caregivers and society. Postponing or slowing decline in any of these areas may represent an important benefit and should be considered as an outcome measure in clinical trials, clinical practice and decision‐making about healthcare budgets. Accepted instruments are available for assessing outcomes in each aspect of Alzheimer's disease, but they need to be selected carefully to provide valid, meaningful data. Some of the most frequently used outcome measures in Alzheimer's disease are reviewed. Using expanded criteria for treatment success and clinically relevant outcome measures, data from currently available studies show that cholinesterase inhibitors produce clinically meaningful long‐term benefits in multiple domains in patients with Alzheimer's disease. Copyright © 2001 John Wiley & Sons, Ltd.
Stochastic league tables: communicating cost‐effectiveness results to decision‐makers
Authors: Hutubessy Raymond C.W. , Baltussen Rob M.P.M. , Evans David B. , Barendregt Jan J. , Murray Christopher J.L. 
Published: September 2002

AbstractThe presentation of the results of uncertainty analysis in cost‐effectiveness analysis (CEA) in the literature has been relatively academic with little attention paid to the question of how decision‐makers should interpret the information particularly when confidence intervals overlap. This question is especially relevant to sectoral CEA providing information on the costs and effects of a wide range of interventions.This paper introduces stochastic league tables to inform decision‐makers about the probability that a specific intervention would be included in the optimal mix of interventions for various levels of resource availability, taking into account the uncertainty surrounding costs and effectiveness. This information helps decision‐makers decide on the relative attractiveness of different intervention mixes, and also on the implications for trading gains in efficiency for gains in other goals such as reducing health inequalities and increasing health system responsiveness. Copyright © 2001 John Wiley & Sons, Ltd.
Stereological estimates of number and length of capillaries in subdivisions of the human hippocampal region
Authors: Løkkegaard Annemette , Nyengaard Jens R. , West Mark J. 
Published: September 2002

AbstractThe hippocampal formation is a neuroanatomically well‐defined region of the brain involved in memory processes. In view of the functional importance of the region and its involvement in a number of brain pathologies, including Alzheimer's disease and temporal lobe epilepsy, a quantitative description of its vascular supply represents an important first step in evaluating the involvement of vascular changes in these phenomena. Unbiased estimates of the length and connectivity of the vascular supply of brain regions have not been described previously. The total number, total length, and distribution of the diameters of capillaries were estimated in the five major subdivisions of the hippocampal formation (fascia dentata, hilus, CA3‐2, CA1, and subiculum) in 5 normal males, 52–84 years of age. These estimates were used to derive several other structural parameters. Both the primary and the derived parameters were used to make inter‐ and intra‐individual comparisons. For each of the five major subdivisions from each individual, the volume was estimated using the Cavalieri principle. The total capillary length was estimated on 3‐μm‐thick plastic isotropic uniform random sections. Using a topological definition of a capillary unit and the optical disector, total capillary number was estimated in 40‐μm‐thick plastic sections. Length‐ and number‐weighted three‐dimensional diameter distributions were obtained from the thin and thick plastic sections, respectively. In each subdivision the total length of capillaries was correlated with previously obtained data on the number of neurons in the same subdivisions of the same individuals. Intersubdivisional differences were observed, in that the hilus of the dentate gyrus had fewer capillaries per unit volume than the other four subdivisions. Interindividual comparisons indicate that the interindividual variances are of a magnitude suitable for sensitive group comparisons. The design‐based stereological methods that were used in the analyses can provide a basis for a new unbiased approach to the estimation of vascular parameters in well‐defined regions of the brain. Hippocampus 2001;11:726–740. © 2001 Wiley‐Liss, Inc.
Optimal estimation of suspended‐sediment concentrations in streams
Authors: Holtschlag David J. 
Published: September 2002

AbstractOptimal estimators are developed for computation of suspended‐sediment concentrations in streams. The estimators are a function of parameters, computed by use of generalized least squares, which simultaneously account for effects of streamflow, seasonal variations in average sediment concentrations, a dynamic error component, and the uncertainty in concentration measurements. The parameters are used in a Kalman filter for on‐line estimation and an associated smoother for off‐line estimation of suspended‐sediment concentrations. The accuracies of the optimal estimators are compared with alternative time‐averaging interpolators and flow‐weighting regression estimators by use of long‐term daily‐mean suspended‐sediment concentration and streamflow data from 10 sites within the United States. For sampling intervals from 3 to 48 days, the standard errors of on‐line and off‐line optimal estimators ranged from 52·7 to 107%, and from 39·5 to 93·0%, respectively. The corresponding standard errors of linear and cubic‐spline interpolators ranged from 48·8 to 158%, and from 50·6 to 176%, respectively. The standard errors of simple and multiple regression estimators, which did not vary with the sampling interval, were 124 and 105%, respectively. Thus, the optimal off‐line estimator (Kalman smoother) had the lowest error characteristics of those evaluated. Because suspended‐sediment concentrations are typically measured at less than 3‐day intervals, use of optimal estimators will likely result in significant improvements in the accuracy of continuous suspended‐sediment concentration records. Additional research on the integration of direct suspended‐sediment concentration measurements and optimal estimators applied at hourly or shorter intervals is needed. Published in 2001 by John Wiley & Sons, Ltd.
Simulation of stream discharge and transport of nitrate and selected herbicides in the Mississippi River Basin
Authors: Broshears Robert E. , Clark Gregory M. , Jobson Harvey E. 
Published: September 2002

AbstractStream discharge and the transport of nitrate, atrazine, and metolachlor in the Mississippi River Basin were simulated using the DAFLOW/BLTM hydrologic model. The simulated domain for stream discharge included river reaches downstream from the following stations in the National Stream Quality Accounting Network: Mississippi River at Clinton, IA; Missouri River at Hermann, MO; Ohio River at Grand Chain, IL; and Arkansas River at Little Rock, AR. Coefficients of hydraulic geometry were calibrated using data from water year 1996; the model was validated by favourable simulation of observed discharges in water years 1992–1994. The transport of nitrate, atrazine, and metolachlor was simulated downstream from the Mississippi River at Thebes, IL, and the Ohio River at Grand Chain. Simulated concentrations compared favourably with observed concentrations at Baton Rouge, LA. Development of this model is a preliminary step in gaining a more quantitative understanding of the sources and fate of nutrients and pesticides delivered from the Mississippi River Basin to the Gulf of Mexico. Published in 2001 by John Wiley & Sons, Ltd.
Annual suspended sediment and trace element fluxes in the Mississippi, Columbia, Colorado, and Rio Grande drainage basins
Authors: Horowitz Arthur J. , Elrick Kent A. , Smith James J. 
Published: September 2002

AbstractSuspended sediment, sediment‐associated, total trace element, phosphorus (P), and total organic carbon (TOC) fluxes were determined for the Mississippi, Columbia, Rio Grande, and Colorado Basins for the study period (the 1996, 1997, and 1998 water years) as part of the US Geological Survey's redesigned National Stream Quality Accounting Network (NASQAN) programme. The majority (≥70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported in association with suspended sediment; Sr transport seems dominated by the dissolved phase, whereas the transport of Li and TOC seems to be divided equally between both phases. Average dissolved trace element levels are markedly lower than reported during the original NASQAN programme; this seems due to the use of ‘clean’ sampling, processing, and analytical techniques rather than to improvements in water quality. Partitioning between sediment and water for Ag, Pb, Cd, Cr, Co, V, Be, As, Sb, Hg, and Ti could not be estimated due to a lack of detectable dissolved concentrations in most samples.Elevated suspended sediment‐associated Zn levels were detected in the Ohio River Basin and elevated Hg levels were detected in the Tennessee River, the former may affect the mainstem Mississippi River, whereas the latter probably do not. Sediment‐associated concentrations of Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe are markedly elevated in the upper Columbia Basin, and appear to be detectable (Zn, Cd) as far downstream as the middle of the basin. These elevated concentrations seem to result from mining and/or mining‐related activities. Consistently detectable concentrations of dissolved Se were found only in the Colorado River Basin.Calculated average annual suspended sediment fluxes at the mouths of the Mississippi and Rio Grande Basins were below, whereas those for the Columbia and Colorado Basins were above previously published annual values. Downstream suspended sediment‐associated and total trace element fluxes increase in the Mississippi and Columbia Basins, whereas fluxes markedly decrease in the Colorado Basin. No consistent pattern in trace element fluxes was detected in the Rio Grande Basin. Published in 2001 by John Wiley & Sons, Ltd.
Carbon and nitrogen isotopic compositions of particulate organic matter in four large river systems across the United States
Authors: Kendall Carol , Silva Steven R. , Kelly Valerie J. 
Published: September 2002

AbstractRiverine particulate organic matter (POM) samples were collected bi‐weekly to monthly from 40 sites in the Mississippi, Colorado, Rio Grande, and Columbia River Basins (USA) in 1996–97 and analysed for carbon and nitrogen stable isotopic compositions. These isotopic compositions and C : N ratios were used to identify four endmember sources of POM: plankton, fresh terrestrial plant material, aquatic plants, and soil organic material. This large‐scale study also incorporated ancillary chemical and hydrologic data to refine and extend the interpretations of POM sources beyond the source characterizations that could be done solely with isotopic and elemental ratios. The ancillary data were especially useful for differentiating between seasonal changes in POM source materials and the effects of local nutrient sources and in‐stream biogeochemical processes.Average values of δ13C and C : N for all four river systems suggested that plankton is the dominant source of POM in these rivers, with higher percentages of plankton downstream of reservoirs. Although the temporal patterns in some rivers are complex, the low δ13C and C : N values in spring and summer probably indicate plankton blooms, whereas relatively elevated values in fall and winter are consistent with greater proportions of decaying aquatic vegetation and/or terrestrial material. Seasonal shifts in the δ13C of POM when the C : N remains relatively constant probably indicate changes in the relative rates of photosynthesis and respiration. Periodic inputs of plant detritus are suggested by C : N ratios >15, principally on the Columbia and Ohio Rivers. The δ15N and δ13C also reflect the importance of internal and external sources of dissolved carbon and nitrogen, and the degree of in‐stream processing. Elevated δ15N values at some sites probably reflect inputs from sewage and/or animal waste. This information on the spatial and temporal variation in sources of POM in four major river systems should prove useful in future food web and nutrient transport studies. Published in 2001 by John Wiley & Sons, Ltd.
Hillslope and wetland hydrodynamics in a tussock grassland, South Island, New Zealand
Authors: Bowden William B. , Fahey Barry D. , Ekanayake Jagath , Murray Dave L. 
Published: September 2002

AbstractPrevious research on two experimental catchments at the Glendhu Forest (Otago) showed that runoff dynamics from this landscape differ substantially from other areas in New Zealand. In particular, the recession curves from these catchments have two distinct phases: a rapid decline for a period of several hours, followed by a slow decline that may last many days to weeks. In the current study, soil water matric potential measurements indicated that perched saturated zones develop very rapidly in the surface (0–30 cm) soil horizons. Deep (50–250 cm) loess horizons remain moist throughout the year and may be near or at saturation at the bedrock contact, and respond only slowly to rain events. Soils in the middle horizons are often drier than the surface soil above or the deep soils below. Throughflow measurements showed that storm runoff occurs primarily as interflow through a retentive but pervious mat of mosses, litter, and roots at the soil surface. Despite the presence of abundant earthworm burrows, less water is transmitted through the soil horizon just below this surface mat. Only a small fraction of stormflow was transmitted through the deep, mineral horizons. However, baseflow could be sustained for long periods (up to 4 weeks) from unsaturated flow of soil moisture stored in the deep loess horizons. Water storage in bog peats and associated riparian soils (which are numerous in this area) is insufficient to sustain baseflow for more than a few days. The results from this study are consistent with previous hydrometric, soils, and isotopic observations and suggest that any land‐use practices that disrupt the surface soil horizons are likely to change the runoff characteristics of this area. Copyright © 2001 John Wiley & Sons, Ltd.
Quantifying contributions to storm runoff through end‐member mixing analysis and hydrologic measurements at the Panola Mountain Research Watershed (Georgia, USA)
Authors: Burns Douglas A. , McDonnell Jeffrey J. , Hooper Richard P. , Peters Norman E. , Freer James E. , Kendall Carol , Beven Keith 
Published: September 2002

AbstractThe geographic sources and hydrologic flow paths of stormflow in small catchments are not well understood because of limitations in sampling methods and insufficient resolution of potential end members. To address these limitations, an extensive hydrologic dataset was collected at a 10 ha catchment at Panola Mountain Research Watershed near Atlanta, GA, to quantify the contribution of three geographic sources of stormflow. Samples of stream water, runoff from an outcrop, and hillslope subsurface stormflow were collected during two rainstorms in the winter of 1996, and an end‐member mixing analysis model that included five solutes was developed. Runoff from the outcrop, which occupies about one‐third of the catchment area, contributed 50–55% of the peak streamflow during the 2 February rainstorm, and 80–85% of the peak streamflow during the 6–7 March rainstorm; it also contributed about 50% to total streamflow during the dry winter conditions that preceded the 6–7 March storm. Riparian groundwater runoff was the largest component of stream runoff (80–100%) early during rising streamflow and throughout stream recession, and contributed about 50% to total stream runoff during the 2 February storm, which was preceded by wet winter conditions. Hillslope runoff contributed 25–30% to peak stream runoff and 15–18% to total stream runoff during both storms. The temporal response of the three runoff components showed general agreement with hydrologic measurements from the catchment during each storm. Estimates of recharge from the outcrop to the riparian aquifer that were independent of model calculations indicated that storage in the riparian aquifer could account for the volume of rain that fell on the outcrop but did not contribute to stream runoff. The results of this study generally indicate that improvements in the ability of mixing models to describe the hydrologic response accurately in forested catchments may depend on better identification, and detailed spatial and temporal characterization of the mobile waters from the principal hydrologic source areas that contribute to stream runoff. Copyright © 2001 John Wiley & Sons, Ltd.