bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endogenous adult neural stem cells: Limits and potential to repair the injured central nervous system
Authors: Picard‐Riera Nathalie , Nait‐Oumesmar Brahim , Baron‐Van Evercooren Anne 
Published: March 2004

AbstractMitotic activity persists in various regions of the adult mammal CNS. While evidences of neurogenesis appeared, many studies focused on the features of the adult stem cells from germinative areas such as the subventricular zone of the lateral ventricles, the dentate gyrus of the hippocampus, the cortex, the fourth ventricle and the central canal of the spinal cord. In the present paper, we review the potentialities of the adult germinative areas in terms of proliferation, migration and differentiation in non pathological situation and in response to different type of CNS injury. Adult endogenous stem cells are activated in response to various injuries but their capacities to migrate and to undergo either neurogenesis or gliogenesis differ according to the lesion‐type and the germinative zone from which they arise. Different works demonstrated that epigenic factors such as growth factors can enhance the repair potential of the adult stem cells. Reactivation and mobilization of endogenous stem cells as well as demonstration of their long‐term survival and functionality appear to be interesting strategies to investigate in order to promote endogenous repair of the adult CNS. © 2004 Wiley‐Liss, Inc.
Do hematopoietic cells exposed to a neurogenic environment mimic properties of endogenous neural precursors?
Authors: Walczak P. , Chen N. , Hudson J.E. , Willing A.E. , Garbuzova‐Davis S.N. , Song S. , Sanberg P.R. , Sanchez‐Ramos J. , Bickford P.C. , Zigova T. 
Published: March 2004

AbstractHematopoietic progenitors are cells, which under challenging experimental conditions can develop unusual phenotypic properties, rather distant from their original mesodermal origin. As previously reported, cells derived from human umbilical cord blood (HUCB) or human bone marrow (BM) under certain in vivo or in vitro conditions can manifest neural features that resemble features of neural‐derived cells, immunocytochemically and in some instances also morphologically. The present study explored how hematopoietic‐derived cells would respond to neurogenic signals from the subventricular zone (SVZ) of adult and aged (6 and 16 months old) rats. The mononuclear fraction of HUCB cells was transplanted into the SVZ of immunosuppressed (single cyclosporin or three‐drug treatment) animals. The triple‐suppression paradigm allowed us to protect transplanted human cells within the brain and to explore further their phenotypic and migratory properties. One week after implantation, many surviving HUCB cells were located within the SVZ and the vertical limb of the rostral migratory stream (RMS). The migration of HUCB cells was restricted exclusively to the pathway leading to the olfactory bulb. In younger animals, grafted cells navigated almost halfway through the vertical limb, whereas, in the older animals, the migration was less pronounced. The overall cell survival was greater in younger animals than in older ones. Immunocytochemistry for surface CD antigen expression showed that many HUCB cells, either cultured or within the brain parenchyma, retained their hematopoietic identity. A few cells, identified by using human‐specific antibodies (anti‐human nuclei, or mitochondria) expressed nestin and doublecortin, markers of endogenous neural progenitors. Therefore, it is believed that the environment of the neurogenic SVZ, even in aged animals, was able to support survival, “neuralization,” and migratory features of HUCB‐derived cells. © 2004 Wiley‐Liss, Inc.
Green fluorescent protein bone marrow cells express hematopoietic and neural antigens in culture and migrate within the neonatal rat brain
Authors: Hudson J.E. , Chen N. , Song S. , Walczak P. , Jendelová P. , Sykova E. , Willing A.E. , Saporta S. , Bickford P. , Sanchez‐Ramos J. , Zigova T. 
Published: March 2004

AbstractFinding a reliable source of alternative neural stem cells for treatment of various diseases and injuries affecting the central nervous system is a challenge. Numerous studies have shown that hematopoietic and nonhematopoietic progenitors derived from bone marrow (BM) under specific conditions are able to differentiate into cells of all three germ layers. Recently, it was reported that cultured, unfractionated (whole) adult BM cells form nestin‐positive spheres that can later initiate neural differentiation (Kabos et al., 2002). The identity of the subpopulation of BM cells that contributes to neural differentiation remains unknown. We therefore analyzed the hematopoietic and neural features of cultured, unfractionated BM cells derived from a transgenic mouse that expresses green fluorescent protein (GFP) in all tissues. We also transplanted the BM cells into the subventricular zone (SVZ), a region known to support postnatal neurogenesis. After injection of BM cells into the neurogenic SVZ in neonatal rats, we found surviving GFP+ BM cells close to the injection site and in various brain regions, including corpus callosum and subcortical white matter. Many of the grafted cells were detected within the rostral migratory stream (RMS), moving toward the olfactory bulb (OB), and some cells reached the subependymal zone of the OB. Our in vitro experiments revealed that murine GFP+ BM cells retained their proliferation and differentiation potential and predominantly preserved their hematopoietic identity (CD45, CD90, CD133), although a few expressed neural antigens (nestin, glial fibrillary acdiic protein, TuJ1). © 2004 Wiley‐Liss, Inc.
Blockade of interleukin‐6 receptor suppresses reactive astrogliosis and ameliorates functional recovery in experimental spinal cord injury
Authors: Okada S. , Nakamura M. , Mikami Y. , Shimazaki T. , Mihara M. , Ohsugi Y. , Iwamoto Y. , Yoshizaki K. , Kishimoto T. , Toyama Y. , Okano H. 
Published: March 2004

AbstractEndogenous neural stem/progenitor cells (NSPCs) have recently been shown to differentiate exclusively into astrocytes, the cells that are involved in glial scar formation after spinal cord injury (SCI). The microenvironment of the spinal cord, especially the inflammatory cytokines that dramatically increase in the acute phase at the injury site, is considered to be an important cause of inhibitory mechanism of neuronal differentiation following SCI. Interleukin‐6 (IL‐6), which has been demonstrated to induce NSPCs to undergo astrocytic differentiation selectively through the JAK/STAT pathway in vitro, has also been demonstrated to play a critical role as a proinflammatory cytokine and to be associated with secondary tissue damage in SCI. In this study, we assessed the efficacy of rat anti‐mouse IL‐6 receptor monoclonal antibody (MR16‐1) in the treatment of acute SCI in mice. Immediately after contusive SCI with a modified NYU impactor, mice were intraperitoneally injected with a single dose of MR16‐1 (100 μg/g body weight), the lesions were assessed histologically, and the functional recovery was evaluated. MR16‐1 not only suppressed the astrocytic diffentiation‐promoting effect of IL‐6 signaling in vitro but inhibited the development of astrogliosis after SCI in vivo. MR16‐1 also decreased the number of invading inflammatory cells and the severity of connective tissue scar formation. In addition, we observed significant functional recovery in the mice treated with MR16‐1 compared with control mice. These findings suggest that neutralization of IL‐6 signaling in the acute phase of SCI represents an attractive option for the treatment of SCI. © 2004 Wiley‐Liss, Inc.
Role of calcium and kinases on the neurotrophic effect induced by γ‐aminobutyric acid
Authors: Fiszman Mónica L. , Schousboe Arne 
Published: March 2004

AbstractAn increasing body of evidence supports a trophic action of γ‐aminobutyric acid (GABA) during nervous system development. The purported mediator of these trophic effects is a depolarizing response triggered by GABA, which elicits a calcium influx in immature CNS cells. This Mini‐Review focuses on the neurotrophic role of neural activity and GABA and some of the most common intracellular cascades activated by depolarization and trophic factors. Several biological effects induced by GABA in the developing nervous system are reviewed, with particular emphasis on what is known about calcium‐dependent neurotrophic effects induced by GABA and its intracellular mechanisms. © 2004 Wiley‐Liss, Inc.
How types of carbonate rock assemblages constrain the distribution of karst rocky desertified land in Guizhou Province, PR China: phenomena and mechanisms
Authors: Wang S.‐J. , Li R.‐L. , Sun C.‐X. , Zhang D.‐F. , Li F.‐Q. , Zhou D.‐Q. , Xiong K.‐N. , Zhou Z.‐F. 
Published: March 2004

AbstractIn southwestern China karst rocky desertification (a process of land degradation involving serious soil erosion, extensive exposure of basement rocks, drastic decrease of soil productivity and the appearance of a desert‐like landscape) results from irrational land use on the fragile, thin karst soil. Soil particles in the Guizhou karst plateau were accumulated predominantly from residues left behind after the dissolution of carbonate rocks, and the thickness of the soil layer is related to the amount of argillaceous substances in the lost carbonate rock. This paper examines the spatial distribution of karst rocky desertified (KRD) land in Guizhou Province, and relates it to the different assemblages of basement carbonate rocks.Types of carbonate rock assemblages are discussed using a 1 : 500000 scale digital‐distribution map. Their distribution and sensitivity to erosion are analysed, demonstrating that the occurrence of KRD land is positively correlated to homogeneous carbonate rocks. Differences in physical and chemical properties of limestone and dolomite rocks lead to differences in dissolution, accumulation rate of soil particles and relief on the surface, and these factors influence land‐use potential. Copyright © 2004 John Wiley & Sons, Ltd.
Local versus expert knowledge in forest management in a semi‐arid part of India
Authors: Sekhar N. Udaya 
Published: March 2004

AbstractThis study analyzes the differences between the villagers' and the Forest Department's preferences in the choice of tree species to be planted in eastern Rajasthan, India. Locals learned to manage the tree resources in a sustainable manner before the formal knowledge perspectives started to dominate through various state forestry programmes in which decision making is dominated by expert perspectives in a given political context. The study also attempts to identify the problems of complementary relationships between local and expert knowledge and the resulting management implications. Copyright © 2004 John Wiley & Sons, Ltd.
AM fungi inoculation and addition of microbially‐treated dry olive cake‐enhanced afforestation of a desertified Mediterranean site
Authors: Caravaca F. , Alguacil M. M. , Vassileva M. , Díaz G. , Roldán A. 
Published: March 2004

AbstractA field experiment was carried out to compare the effectiveness of inoculation with three arbuscular mycorrhizal (AM) fungi, namelyGlomus intraradicesSchenck & Smith,Glomus deserticola(Trappe, Bloss. & Menge) andGlomus mosseae(Nicol & Gerd.) Gerd. & Trappe, and the addition ofAspergillus niger‐treated dry olive cake (DOC) in the presence of rock phosphate, in increasing root nitrate reductase (NR) and acid phosphatase activities, mycorrhizal colonization, plant growth and nutrient uptake inDorycnium pentaphyllumL. seedlings afforested in a semiarid degraded soil. Three months after planting, both the addition of fermented DOC and the mycorrhizal inoculation treatments had increased root NR activity significantly, particularly the inoculation withG. deserticola(by 75 per cent with respect to non‐inoculated plants), but they had no effect on root acid phosphatase. Mycorrhizal inoculation treatments withG. deserticolaorG. mosseaeon their own were even more effective than the addition of fermented DOC alone in improving the growth and (NPK) foliar nutrients ofD. pentaphyllumplants. The combined treatment involving the application of microbially‐treated agrowastes and mycorrhizal inoculation with AM fungi, particularly withG. mosseae, can be proposed as a successful revegetation strategy forD. pentaphyllumin P‐deficient soils under semiarid Mediterranean conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Desertification problems in the Yangtze River source area, China
Authors: Yan P. , Dong G. R. , Su Z. Z. , Zhang D. S. 
Published: March 2004

AbstractDesertification in the source area of Yangtze River is discussed in the paper. Under the conditions of the cold climate and permafrost, the freeze–thaw processes have significant effects on the different kinds of desertification. The classification, distribution, development, formation and control measurements of desertification in the source area are in particular compared with other desertified regions in east China. Furthermore, suggestions for desertification research and control in the source area are put forward. Copyright © 2004 John Wiley & Sons, Ltd.
Cementite transformation in low carbon steel under the influence of sulphur
Authors: Hucińska J. 
Published: March 2004

Abstract Cementite/Fe3C carbide in a commercial low carbon steel after prolonged service in naphtha environment with traces of sulphur of 0.3 ppm and at a temperature of 200–220°C has been examined. It has been stated that under the influence of sulphur, cementite at the steel surface and inside the steel is transformed into an unstable quasi‐crystalline phase enriched with sulphur/tramp elements and iron depletion. Cementite transformation and disintegration of the degraded carbide phase is connected with a release of carbon that diffuses into the steel in front of the sulphur diffusion zone. Beneath the steel surface a layer of low carbon content forms, followed by a zone of higher carbon content.
Optical detection methods for mass spectrometry of macroions
Authors: Peng Wen‐Ping , Cai Yong , Chang Huan‐Cheng 
Published: March 2004

Abstract

I.
Introduction
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II.
Macroion Detection Methods
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A.  Energy‐Sensitive Detection
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B.  Charge‐Sensitive Detection
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C.  Photon‐Sensitive Detection
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1.  ELS
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2.   LIF
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III
Applications to Micron‐Sized and Nano‐Sized Particles
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A.  Ion Sources
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B.  Mass Analyzers
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C.  Detectors
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1.  ELS/Ellipsoidal Reflector
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2.  LIF/Ion Trap
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IV.
Conclusions and Outlook
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Acknowledgments
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References
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Detection of macroions has been a challenge in the field of mass spectrometry. Conventional ionization‐based detectors, relying on production and multiplication of secondary electrons, are restricted to detection for charged particles of m/z < 1 × 106. While both energy‐sensitive and charge‐sensitive detectors have been developed recently to overcome the limitation, they are not yet in common use. Photon‐sensitive detectors are suggested to be an alternative, with which detection of macroions (or charged particles) by either elastic light scattering (ELS) or laser‐induced fluorescence (LIF) has been possible. In this article, we provide a critical review on the developments of novel optical detection methods for mass spectrometry of macroions, including both micron‐sized and nano‐sized synthetic polymers as well as high‐mass biomolecules. Design and development of new spectrometers making possible observations of the mass spectra of macroions with sizes in the range of 10–103 nm or masses in the range of 1–106 MDa are illustrated. The potential and promise of this optical approach toward macroion detection with high efficiency are discussed in practical aspects. © 2004 Wiley Periodicals, Inc.,Mass Spec Rev
Dynamic Density Functional Theory for Sheared Polymeric Systems
Authors: Zvelindovsky A. V. , Sevink G. J. A. , Lyakhova K. S. , Altevogt P. 
Published: March 2004

AbstractSummary:Details of the dynamic density functional theory for sheared polymer systems are presented. The method is illustrated on polymer blends with and without compatibilizers. Shearing slows down coarsening of structures at later stages of phase separation, trapping the system in kineticly driven metastable states. Under certain conditions the system is found trapped in a metastable multiple sphere morphology, while under other conditions a sphere‐to‐string transition is observed. The results are sensitive to the (block co)polymer architecture.The morphology of a symmetric polymer blend in a 32 × 32 box.imageThe morphology of a symmetric polymer blend in a 32 × 32 box.
A Protocol for the Estimation of Parameters in Process Models: Case Studies with Polymerization Scenarios
Authors: Polic A. Loui , Lona Liliane M. F. , Duever Thomas A. , Penlidis Alexander 
Published: March 2004

AbstractSummary: As our understanding of chemical processes increases, the complexity of the models developed to describe them also increases. In most cases the equations are nonlinear in the inputs and parameters, and must be solved numerically. At present in estimating parameters for large process models, there are two shortcomings in the existing knowledge about (multiresponse) parameter estimation. The first is, how effective is the present parameter estimation methodology when applied to large models, and the second is, can any advantage be gained from considering the parameter estimation problem as a whole. This paper will address these questions, by revisiting the various steps of a parameter estimation protocol. There is little discussion in the literature as to how all the steps for parameter estimation are related. In the development of this protocol all of the steps for parameter estimation will be revisited: parameter sensitivity analysis, statistical design of experiments, estimation of parameters and confidence regions. By considering all these steps as a whole the overall parameter estimation procedure can be more efficient and some pitfalls, such as local optima and incorrect confidence regions, may be dealt with in an appropriate manner. To illustrate the application of the protocol, two case studies related to polymerization models are presented. These case studies illustrate some of the problems that may be encountered in the parameter estimation process and how the proposed protocol can aid in overcoming them.Plot of conversion versus time for the copolymerization of styrene/methyl methacrylate.imagePlot of conversion versus time for the copolymerization of styrene/methyl methacrylate.
Measurement of fat/water ratios in rat liver using 3D three‐point dixon MRI
Authors: Zhang Xiaowei , Tengowski Mark , Fasulo Lisa , Botts Suzanne , Suddarth Steve A. , Johnson G. Allan 
Published: March 2004

AbstractHepatic steatosis, or fatty liver, is commonly observed during the animal phase of drug safety studies. A noninvasive three‐dimensional (3D) three‐point Dixon method was used to quantitatively evaluate the fatty livers of rats induced by an experimental microsomal transfer protein (MTP) inhibitor, in an effort to develop a safety biomarker that could be translated to human studies. The method was implemented at 2.0 T for in vivo studies, and at 7.1 T for higher‐resolution magnetic resonance (MR) histologic studies. In three separate protocols to study dose response and longitudinal evolution, intrahepatic fatty accumulation was detected by this method and confirmed by chemical and histologic assessments. Consistent with the pathologic changes, the fat/water ratios estimated by the MR technique increased significantly at doses of 1 mg/kg and 100 mg/kg of MTP inhibitor after 14 days of continuous administration. Among the more important findings were: 1) with the 3D three‐point Dixon method, in vivo longitudinal studies of liver fat distribution can be conducted at significantly higher resolution than has previously been reported; 2) MR histology allows delineation of distribution at the microscopic scale of 0.0024 mm3 resolution; and 3) the 3D three‐point Dixon technique provides relative estimates of liver fat content and distribution at a high confidence level. This technique will be applicable in future studies in which fatty liver is a potential safety issue. Magn Reson Med 51:697–702, 2004. © 2004 Wiley‐Liss, Inc.
Cardiac SSFP imaging at 3 Tesla
Authors: Schär Michael , Kozerke Sebastian , Fischer Stefan E. , Boesiger Peter 
Published: March 2004

AbstractBalanced steady‐state free precession (SSFP) techniques provide excellent contrast between myocardium and blood at a high signal‐to‐noise ratio (SNR). Hence, SSFP imaging has become the method of choice for assessing cardiac function at 1.5T. The expected improvement in SNR at higher field strength prompted us to implement SSFP at 3.0T. In this work, an optimized sequence protocol for cardiac SSFP imaging at 3.0T is derived, taking into account several partly adverse effects at higher field, such as increased field inhomogeneities, longer T1, and power deposition limitations. SSFP contrast is established by optimizing the maximum amplitude of the radiofrequency (RF) field strength for shortest TR, as well as by localized linear or second‐order shimming and local optimization of the resonance frequency. Given the increased SNR, sensitivity encoding (SENSE) can be employed to shorten breath‐hold times. Short‐axis, long‐axis, and four‐chamber cine views obtained in healthy adult subjects are presented, and three different types of artifacts are discussed along with potential methods for reducing them. Magn Reson Med 51:799–806, 2004. © 2004 Wiley‐Liss, Inc.
Dynamic estimation of the myocardial oxygen extraction ratio during dipyridamole stress by MRI: A preliminary study in canines
Authors: Zheng Jie , Wang Jinghua , Nolte Mark , Li Debiao , Gropler Robert J. , Woodard Pamela K. 
Published: March 2004

AbstractThe myocardial oxygen extraction fraction (OEF) reflects the balance between myocardial oxygen supply and demand. The feasibility of quantifying myocardial OEF was demonstrated with MRI during pharmacologic vasodilation in dogs. Dipyridamole was infused intravenously to increase blood flow and change in myocardial oxygen content. Arterial and coronary sinus blood sampling was performed during dipyridamole‐induced vasodilation to measure the myocardial blood oxygen content. Myocardial T2 was measured dynamically during the vasodilation, and quantified with a simplified diffusion model as a function of myocardial OEF and blood volume. The results showed a strong correlation (R2 = 0.89) between myocardial OEF values measured by MRI and those measured by blood sampling. Regional differences in the OEF were demonstrated by direct infusion of dipyridamole into coronary arteries in dogs. Combined with vasodilator stress, dynamic assessments of the OEF may provide a putative measurement of myocardial flow reserve and allow consecutive monitoring of myocardial dose and response. Magn Reson Med 51:718–726, 2004. © 2004 Wiley‐Liss, Inc.
Automatic tuning and matching of a small multifrequency saddle coil at 4.7 T
Authors: Pérez de Alejo Rigoberto , Garrido Carlos , Villa Palmira , Rodriguez Ignacio , Vaquero Juan José , Ruiz‐Cabello Jesús , Cortijo Manuel 
Published: March 2004

AbstractA new circuit design for automatically tuning and matching a saddle coil for small animal imaging is presented. This design allows working at 1H, 19F, and 3He resonance frequencies in a 4.7 T spectrometer. It is based on a balanced circuit with commercial variable capacity diodes controlled by a computer using digital potentiometers. The change between two different frequencies can be accurately performed in a few seconds. System Q is compared, between 140–210 MHz, to the same coil tuned and matched with high Q variable capacitors. Differences lower than 5% were found with a loaded coil. The proposed design has initially been evaluated in 19F and 1H NMR images acquired with a five‐tube phantom. An application is also shown for the acquisition of 3He, 19F, and 1H lung images in a control rat. Magn Reson Med 51:869–873, 2004. © 2004 Wiley‐Liss, Inc.