bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incidence and trends in pediatric malignancies medulloblastoma/primitive neuroectodermal tumor: A SEER update
Authors: McNeil Dawn Elizabeth , Coté Timothy R. , Clegg Limin , Rorke Lucy Balian 
Published: October 2002

AbstractBackgroundIt has been suggested that cerebellar medulloblastoma (M) and primitive neuroectodermal tumors (PNET) arising elsewhere in the nervous system, represent a single entity (M/PNET), although this concept is controversial. Cancer registries permit population‐based description of cases reported as medulloblastoma, those reported as PNET and description of the aggregate, M/PNET.ProcedureWe reviewed the 768 cases of M/PNET (633 diagnosed medulloblastoma and 135 diagnosed PNET) among persons under 20 years of age in the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database.ResultsThe incidence of M/PNET rose 23%, from 4 per 106 person‐years in 1973–77 to 4.9 per 106 person‐years in 1993–98. Cases reported as PNET were more likely than those reported as medulloblastoma to be supratentorial (30.4% vs. 1.9%, P < 0.001) and to be female (42.2% vs. 35.4%, P = 0.13). The difference in 5‐year survival between the 600 children with infratentorial medulloblastoma vs. the 49 children with infratentorial PNET was not statistically significant (55% vs. 43%). Regardless of reporting diagnosis, survival was poorer among children age 0–3 years and those with supratentorial tumors. Children diagnosed in the more recent period from 1985–1998 had a longer median survival than children diagnosed in 1973–84 (4.9 years vs. 10 years, P < 0.05). Rates were 42% higher among Whites compared to Blacks (4.5/106 person‐years vs. 3.1/106 person‐years, P < 0.01).ConclusionsWe found M/PNET is increasing in incidence and more frequent among Whites. Given that medulloblastoma and PNET are histologically identical and have similar epidemiologic profiles, future studies should provide analyses that combine these entities. Med Pediatr Oncol 2002;39:190–194. Published 2002 Wiley‐Liss, Inc.
MeCP2 and other methyl‐cpg binding proteins
Authors: Jørgensen Helle Færk , Bird Adrian 
Published: October 2002

AbstractDNA methylation is an epigenetic modification that is implicated in transcriptional silencing. Recently, it has become increasingly clear that both correct levels and proper interpretation of methylation are important factors for normal development and function of the human organism. One example is the neurological disorder Rett syndrome (RTT), which affects approximately one in 10,000 girls. RTT is caused by mutations in MeCP2, a protein that was identified by its ability to bind specifically to CpG‐methylated DNA. Furthermore, MeCP2 represses transcription in a methylation‐dependent manner, and it is the founding member of the family of methyl‐CpG binding domain (MBD) proteins. MRDD Research Reviews 2002;8:87–93. © 2002 Wiley‐Liss, Inc.
Water exchange and inflow affect the accuracy of T1‐GRE blood volume measurements: Implications for the evaluation of tumor angiogenesis
Authors: Kim Y.R. , Rebro K.J. , Schmainda K.M. 
Published: October 2002

AbstractThe goal of this study was to determine the degree to which vascular water exchange and blood flowing into an imaging slice affect the accuracy of blood volume measurements of brain and tumor tissue when using intravascular T1 contrast agents. The study was performed using 2D and 3D gradient‐echo imaging sequences, since these are two of the most commonly used MRI methods used to evaluate tissue blood volume fraction. Computer simulations were performed and measurements made in a rat 9L gliosarcoma brain tumor model. The computer simulations demonstrate that, with either water exchange or inflow effects alone, the dependence on the physiologic and imaging parameters can be well characterized and therefore potentially offset. In the exchange only case, the parametric dependence of 3D simulations suggest that the best accuracy is achieved with high flip angles, short TR, and low blood contrast agent concentrations. However, for a 2D GRE sequence which is influenced by both water exchange and inflow, the simulations predict that the error trend as a function of the imaging and physiologic parameters is unpredictable and therefore difficult to compensate. With both 2D and 3D GRE the measured blood volume data in rat brain and tumor tissue demonstrate tissue‐specific trends, which reflect differences in the considered physiologic parameters. The experimental data strongly support the computer simulations and also indicate that minimization of the physiological effects by proper selection of imaging parameters, contrast concentration, and volume calculation methods is crucial for accurate assessment of absolute blood volume fraction. Magn Reson Med 47:1110–1120, 2002. © 2002 Wiley‐Liss, Inc.
Oxygen‐enhanced MRI of the brain
Authors: Losert Christoph , Peller Michael , Schneider Philipp , Reiser Maximilian 
Published: October 2002

AbstractBlood oxygenation level‐dependent (BOLD) contrast MRI is a potential method for a physiological characterization of tissue beyond mere morphological representation. The purpose of this study was to develop evaluation techniques for such examinations using a hyperoxia challenge. Administration of pure oxygen was applied to test these techniques, as pure oxygen can be expected to induce relatively small signal intensity (SI) changes compared to CO2‐containing gases and thus requires very sensitive evaluation methods. Fourteen volunteers were investigated by alternating between breathing 100% O2 and normal air, using two different paradigms of administration. Changes ranged from >30% in large veins to 1.71% ± 0.14% in basal ganglia and 0.82% ± 0.08% in white matter. To account for a slow physiological response function, a reference for correlation analysis was derived from the venous reaction. An objective method is presented that allows the adaptation of the significance threshold to the complexity of the paradigm used. Reference signal characteristics in representative brain tissue regions were established. As the presented evaluation scheme proved its applicability to small SI changes induced by pure oxygen, it can readily be used for similar experiments with other gases. Magn Reson Med 48:271–277, 2002. © 2002 Wiley‐Liss, Inc.
Evaluation of 2‐D Green's boundary formula and its normal derivative using Legendre polynomials, with an application to acoustic scattering problems
Authors: Yang S. A. 
Published: October 2002

AbstractThis paper presents the non‐singular forms, in a global sense, of two‐dimensional Green's boundary formula and its normal derivative. The main advantage of the modified formulations is that they are amenable to solution by directly applying standard quadrature formulas over the entire integration domain; that is, the proposed element‐free method requires only nodal data. The approach includes expressing the unknown function as a truncated Fourier–Legendre series, together with transforming the integration interval [a, b] to [‐1,1] ; the series coefficients are thus to be determined. The hypersingular integral, interpreted in the Hadamard finite‐part sense, and some weakly singular integrals can be evaluated analytically; the remaining integrals are regular with the limiting values of the integrands defined explicitly when a source point coincides with a field point. The effectiveness of the modified formulations is examined by an elliptic cylinder subject to prescribed boundary conditions.The regularization is further applied to acoustic scattering problems. The well‐known Burton–Miller method, using a linear combination of the surface Helmholtz integral equation and its normal derivative, is adopted to overcome the non‐uniqueness problem. A general non‐singular form of the composite equation is derived. Comparisons with analytical solutions for acoustically soft and hard circular cylinders are made. Copyright © 2001 John Wiley & Sons, Ltd.
A new numerical method for the boundary optimal control problems of the heat conduction equation
Authors: Park H. M. , Lee W. J. 
Published: October 2002

AbstractA new numerical method is developed for the boundary optimal control problems of the heat conduction equation in the present paper. When the boundary optimal control problem is solved by minimizing the objective function employing a conjugate‐gradient method, the most crucial step is the determination of the gradient of objective function usually employing either the direct differentiation method or the adjoint variable method. The direct differentiation method is simple to implement and always yields accurate results, but consumes a large amount of computational time. Although the adjoint variable method is computationally very efficient, the adjoint variable does not have sufficient regularity at the boundary for the boundary optimal control problems. As a result, a large numerical error is incurred in the evaluation of the gradient function, resulting in premature termination of the conjugate gradient iteration. In the present investigation, a new method is developed that circumvents this difficulty with the adjoint variable method by introducing a partial differential equation that describes the temporal and spatial dynamics of the control variable at the boundary. The present method is applied to the Neumann and Dirichlet boundary optimal control problems, respectively, and is found to solve the problems efficiently with sufficient accuracy. Copyright © 2001 John Wiley & Sons, Ltd.
Implementation of cyclic plasticity models based on a general form of kinematic hardening
Authors: Kobayashi Mineo , Ohno Nobutada 
Published: October 2002

AbstractThis paper deals with implementation of cyclic plastic constitutive models in which a general form of strain hardening and dynamic recovery is employed to represent the multilinear, as well as non‐linear, evolution of back stress. First, in order to incorporate such a general form of kinematic hardening in finite element methods, successive substitution and its convergence are discussed for implicitly integrating stress; moreover, a new expression of consistent tangent modulus is derived by introducing a set of fourth‐rank constitutive parameters into discretized kinematic hardening. Then, the constitutive parameters introduced are specified in three cases of the general form of kinematic hardening; the three cases have distinct capabilities of simulating ratcheting and cyclic stress relaxation. Numerical examples are given to verify the convergence in successive substitution and the new expression of consistent tangent stiffness. Error maps for implicitly integrating stress under non‐proportional as well as proportional loading are also given to show that the multilinear case of the general form provides high accuracy even if strain increment is very large. Copyright © 2002 John Wiley & Sons, Ltd.
Solution of contact optimization problems of cylindrical bodies usinghp‐FEM
Authors: Páczelt I. , Szabó T. 
Published: October 2002

AbstractThis paper is concerned with a numerical solution of contact optimization problems using displacement‐basedhp‐FEM. Small displacements and deformations are assumed for linear elastic material. The contact optimization problem is performed by controlling the contact pressure. The Coulomb friction is also considered. Special attention is paid to the treatment of the jumps in the displacement derivatives at special points. The mesh is adjusted adaptively so that both the boundary of the contact zone and the boundary of the adhesion and slip zones are nodal points. Examples are presented for axially symmetric problems. Copyright © 2001 John Wiley & Sons, Ltd.
Towards advanced circuit board materials: adhesion of copper foil to ultra‐high molecular weight polyethylene composite
Authors: Rein Dmitry M. , Vaykhansky Lev , Cohen Yachin 
Published: October 2002

AbstractPolyethylene based composites are attractive materials for advanced circuit board applications because of their unique combination of properties: low dielectric constant and loss factor, light weight, high flexural modulus and low thermal expansion coefficient controlled in all spatial directions. This investigation describes a process to consolidate chopped fibers of ultra‐high molecular weight polyethylene concurrently with its bonding to a copper foil. Bonding is affected by a thin sheet of low‐density polyethylene, incorporating a crosslinking agent with a concentration gradient across the sheets thickness. In this single step process, the composite material is formed and bonded to the metal foil, achieving good adhesion without the use of extraneous glue. Copyright © 2002 John Wiley & Sons, Ltd.
Inflammatory myofibroblastic tumour (inflammatory pseudotumour) of the breast. Clinicopathological and genetic analysis of a case with evidence for clonality
Authors: Sastre‐Garau Xavier , Couturier Jérôme , Derré Josette , Aurias Alain , Klijanienko Jerzy , Lagacé Réal 
Published: October 2002

AbstractInflammatory myofibroblastic tumours (IMTs) were initially considered to be benign reactive processes, but cases with an unfavourable outcome have been reported. Moreover, clonal genetic alterations have recently been published in some cases, suggesting that IMT may represent a malignant neoplastic entity. This paper reports a case of IMT that developed in the mammary gland, an unusual site. The histological picture was characterized by a proliferation of spindle cells with little cellular atypia and rare mitoses, associated with a polymorphous inflammatory infiltrate. Their immunophenotype, characterized by the expression of vimentin, smooth muscle actin, and cytokeratins, corresponded to that of myofibroblasts. Cytogenetic analysis revealed the clonal nature of the lesion. The modal karyotype was 48, X, ins(2;X)(q34;p21.2p22.2), +7, del(9)(p23), +19. Including the present observation, a 9p deletion has now been found in three cases of IMT. These observations show that IMT may be a clonal neoplasm, even in sites different from deep soft tissues. Copyright © 2001 John Wiley & Sons, Ltd.
Medin and medin‐amyloid in ageing inflamed and non‐inflamed temporal arteries
Authors: Peng Siwei , Westermark Gunilla T. , Näslund Jan , Häggqvist Bo , Glennert Johanna , Westermark Per 
Published: October 2002

AbstractSmall amyloid deposits commonly occur along the internal elastic lamina of the temporal artery. In temporal artery biopsies from 22 patients with histological signs of giant cell arteritis and 25 without, amyloid deposits were found in 14 and 21 biopsies, respectively. Two specific peptide antisera show that this amyloid is identical to the recently identified medin‐amyloid in the ageing aorta. On immunoelectron microscopy, the amyloid appeared topographically closely related to the elastic material. Furthermore, fragmented elastic material was often immunolabelled for medin and found to be engulfed by giant cells. Medin is an internal fragment of the larger precursor lactadherin and is presumably formed by specific enzymatic cleavage events. In situ hybridization showed that lactadherin is expressed locally by smooth muscle cells of the temporal artery. Given the potential role of lactadherin as a mediator for the adhesion of cells, including macrophages, to other cells or surfaces, lactadherin or its fragment medin may be important in the inflammatory process in giant cell arteritis. Copyright © 2001 John Wiley & Sons, Ltd.
Skin flap‐induced regression of granulation tissue correlates with reduced growth factor and increased metalloproteinase expression
Authors: Darby Ian A. , Bisucci Teresa , Pittet Brigitte , Garbin Stefania , Gabbiani Giulio , Desmoulière Alexis 
Published: October 2002

AbstractPrevious studies have shown that covering granulation tissue of a full‐thickness skin wound by a vascularized skin flap induces tissue remodeling, with a rapid loss of granulation tissue cells by apoptosis. In the present study, in situ hybridization has been used to examine mRNA expression for several factors that may be implicated in the apoptosis seen in this tissue. Skin wounds were made on the dorsal skin of 8‐week‐old rats. Ten days after wounding, skin flaps were created surgically and sutured over the granulation tissue. Tissue sections of granulation tissue from various times after addition of the skin flap were hybridized with 33P‐labelled cRNA probes for transforming growth factor‐β1 (TGF‐β1), beta‐inducible gene H3 (β‐ig‐h3), α1 (I) procollagen, α‐smooth muscle actin, matrix metalloproteinase‐13 (MMP‐13) and ‐2 (MMP‐2), tissue inhibitor of metalloproteinase‐1 (TIMP‐1), and inducible nitric oxide synthase (iNOS). Control granulation tissue prior to addition of the skin flap showed high levels of TGF‐β1, β‐ig‐h3, α1 (I) procollagen, α‐smooth muscle actin, and TIMP‐1 expression. MMP‐13, MMP‐2, and iNOS mRNA were low in 10‐day granulation tissue. Addition of a skin flap resulted in a decrease in the expression of TGF‐β1, β‐ig‐h3, α1 (I) procollagen, α‐smooth muscle actin, and TIMP‐1, but increased expression of MMP‐13 and MMP‐2. Similarly, an increase in iNOS mRNA expression was observed in the granulation tissue after addition of the skin flap. Addition of a vascularized skin flap may result in rapid remodelling of granulation tissue due to a decrease in expression ofthe trophic growth factor TGF‐β1 and increased degradation of extracellular matrix due to an alteration in the balance between MMPs and their inhibitor, TIMP‐1. Additionally, increased iNOS expression may also favour apoptosis through the generation of free radicals. The additive effect of reduced growth factor expression, increased extracellular matrix turnover, and nitric oxide generation may result in the fibroblast and vascular cell apoptosis seen during the rapid remodelling of this tissue. Copyright © 2002 John Wiley & Sons, Ltd.
Retracted: Evidence for the early involvement of interleukin 17 in human and experimental renal allograft rejection
Authors: Loong Che‐Chuan , Hsieh Hsian‐Guey , Lui Wing‐Yiu , Chen Ann , Lin Ching‐Yuang 
Published: October 2002

AbstractInflammatory processes can stimulate renal epithelial cells to release cytokines, chemoattractants and matrix proteins into the interstitium, thus contributing to interstitial injury during acute allograft rejection. To test the role of interleukin 17 (IL‐17) in this process, cultured human renal epithelial cells (hRECs) were first established and treated with or without human IL‐17 (hIL‐17) for 2, 4, 8 and 10 h in vitro. Significant elevations of IL‐6 and IL‐8 levels were noted in the supernatants in a dose‐dependent and time‐dependent manner, as also for IL‐6 mRNA expression. Secondly, using a rat acute allograft rejection model, the correlation between IL‐17 expression and histopathological changes was serially studied. The results demonstrated that increased expression of IL‐17 protein on infiltrating mononuclear cells (MNCs) was detectable on day 2. This corresponds to the borderline change of acute rejection according to the Banff classification, and it increased progressively to day 5. Serial study of IL‐6, IL‐8 and IL‐17 mRNA expression of the renal allograft confirmed IL‐17 mRNA expression in the allograft early on post‐transplant day 2, whereas IL‐6 and IL‐8 expression started on day 3. Thirdly, IL‐17 expression was observed in human renal allograft and urinary sediment. IL‐17 protein expression was found in human subclinical (borderline) rejection renal allograft biopsy tissue and none in biopsy tissue not showing any evidence of rejection. There was also a 100% detectable rate of IL‐17 mRNA expression in the MNCs of urinary sediment of patients with subclinical borderline rejection. These results demonstrate that hRECs exposed to IL‐17 can produce inflammatory mediators with the potential to stimulate early alloimmune responses, which may also serve to give warning of acute renal allograft rejection. Copyright © 2002 John Wiley & Sons, Ltd.
Hepatic stem cells
Authors: Forbes Stuart , Vig Pamela , Poulsom Richard , Thomas Howard , Alison Malcolm 
Published: October 2002

AbstractThe liver in an adult healthy body maintains a balance between cell gain and cell loss. Though normally proliferatively quiescent, hepatocyte loss such as that caused by partial hepatectomy, uncomplicated by virus infection or inflammation, invokes a rapid regenerative response to restore liver mass. This restoration of moderate cell loss and ‘wear and tear’ renewal is largely achieved by hepatocyte self‐replication. Furthermore, hepatocyte transplants in animals have shown that a certain proportion of hepatocytes can undergo significant clonal expansion, suggesting that hepatocytes themselves are the functional stem cells of the liver. More severe liver injury can activate a potential stem cell compartment located within the intrahepatic biliary tree, giving rise to cords of bipotential so‐called oval cells within the lobules that can differentiate into hepatocytes and biliary epithelial cells. A third population of stem cells with hepatic potential resides in the bone marrow; these haematopoietic stem cells can contribute to the albeit low renewal rate of hepatocytes, make a more significant contribution to regeneration, and even completely restore normal function in a murine model of hereditary tyrosinaemia. How these three stem cell populations integrate together to achieve a homeostatic balance is not known. This review focuses on two major aspects of liver stem cell biology: firstly, the identity of the liver stem cells, and secondly, their potential value in the treatment of major liver disease. Copyright © 2002 John Wiley & Sons, Ltd.
Expression and localization of HGF and met in Wilms' tumours
Authors: Alami Jennifer , Williams Bryan R. G. , Yeger Herman 
Published: October 2002

AbstractA number of growth factors and cognate receptors that contribute to normal kidney development have been shown to play roles in the pathogenesis of Wilms' tumours. Expression of both hepatocyte growth factor (HGF) and its tyrosine kinase receptor met has been demonstrated in normal tissues and their neoplastic counterparts, implicating these factors in normal development and tumour progression. HGF and met expression has not been studied in Wilms' tumour. Since HGF and met function in a paracrine fashion by regulating tubulogenesis in normal kidney development, they could be involved in the pathogenesis of Wilms' tumour, in which tubular formation is dysplastic. In the present study, a series of ten homotypic (consisting of blastemal, epithelial, and stromal elements) and ten heterotypic (consisting of triphasic histology and a muscle component) Wilms' tumour cases were examined for expression of HGF and met, using in situ hybridization, immunohistochemistry, and western blot analysis. Relatively high met message and protein expression, compared with normal kidney, were evident in homotypic and heterotypic tumour blastemal, epithelial, and rhabdomyoblastic cells and a 145 kD met polypeptide was found in all tumours, with a few cases also expressing the 170 kD precursor form. No apparent alterations of the met receptor were observed. Similarly, HGF protein was also abundantly expressed in blastemal, epithelial, and rhabdomyoblastic cells of the homotypic and heterotypic Wilms' tumours and a 69 kD HGF polypeptide was demonstrated by western blot analysis. Immunohistochemistry for the Ki‐67 proliferation marker indicated that the pattern of Ki‐67 expression correlated with the HGF and met pattern of expression in both homotypic and heterotypic tumours. These results reveal, for the first time, significant co‐expression of met/HGF in Wilms' tumours, with a correspondingly high proliferative index in the same cell groups. Copyright © 2001 John Wiley & Sons, Ltd.