bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of an efficient GLC system with a mixed chiral stationary phase and its application to the separation of optical isomers
Authors: Tamogami Shigeyuki , Awano Ken‐ichi , Amaike Masayasu , Takagi Yoshikazu , Kitahara Takeshi
Published: August 2002

In order to overcome the limitations of the methodology for the separation of enantiomers in GLC analysis, we successfully developed a novel GLC column named ‘Chiramix’, coated with a mixture of two chiral stationary phases, heptakis‐(2,6‐di‐O‐methyl‐3‐O‐pentyl)‐β‐cyclodextrin (2,6‐Me‐3‐Pe‐β‐CD) and octakis‐(2,6‐di‐O‐methyl‐3‐O‐trifluoroacetyl)‐γ‐cyclodextrin (2,6‐Me‐3‐TFAc‐γ‐CD). It was proved that the ‘Chiramix’ column is greatly superior to those with a single chiral phase for separating enantiomers of compounds with various functional groups. As a successful example, this was applied to the analysis of multicomponent systems, such as peach flavours, and the enantiomeric purities of several components of monoterpene hydrocarbons, alcohols, ketones and lactones were determined exactly and simultaneously. Copyright © 2001 John Wiley & Sons, Ltd.
Essential oil composition of Thymus lotocephallus G. López & R. Morales, collected during flowering and vegetative phases
Authors: Cristina Figueiredo A. , Miguel M. G. , Duarte A. M. F. , Barroso José G. , Pedro Luis G.
Published: August 2002

The aerial parts of Thymus lotocephalus were collected during the flowering and vegetative phases of the plant in the Algarve, Portugal. The oils were isolated by hydrodistillation and distillation–extraction and analysed by GC and GC–MS. The oil isolated from the flowers was obtained in a yield of 0.9%, whereas those isolated from the leaves during flowering and vegetative phases showed lower yields, 0.7% and 0.2% (v/w), respectively. The oils isolated from both the flowers and the leaves were dominated by the oxygen‐containing monoterpenes (57–64%). The monoterpene hydrocarbons (11–22%) and the oxygen‐containing sesquiterpenes (7–14%) were the two other main fractions of these oils. 1,8‐Cineole (10–19%), linalyl acetate (6–14%) and linalol (4–12%) were the main components of all the oils studied. Intermedeol (2–4%), β‐caryophyllene oxide (2–3%) and viridiflorol (1–3%) were the main components of the oxygen‐containing sesquiterpene fraction. The diterpene abietatriene was present in trace amounts (<0.05%) in all the oils. Depending on the plant part studied and on the isolation procedure used, these oils can be characterized either by 1,8‐cineole/linalol/linalyl acetate or 1,8‐cineole type. Copyright © 2001 John Wiley & Sons, Ltd.
Reconstruction of lavandulol carbon skeleton based on limonene. Synthesis of isotetrahydrolavandulol
Authors: Kula Józef , Wilczyńska Janina , Chmielecka Ilona
Published: August 2002

Starting from limonene 2,5,6‐trimethylheptan‐1‐ol, an alcohol with a lavandulol skeleton have been synthesized. The key step of the synthesis was catalytic hydrogenolysis of 3‐isopropenyl‐6‐oxo‐heptanal, providing 5,6‐dimethylheptan‐2‐ol in a good yield. Copyright © 2001 John Wiley & Sons, Ltd.
Edge‐based finite element method for shallow water equations
Authors: Ribeiro F. L. B. , Galeão A. C. , Landau L.
Published: August 2002

This paper describes an edge‐based implementation of the generalized residual minimum (GMRES) solver for the fully coupled solution of non‐linear systems arising from finite element discretization of shallow water equations (SWEs). The gain in terms of memory, floating point operations and indirect addressing is quantified for semi‐discrete and space–time analyses. Stabilized formulations, including Petrov–Galerkin models and discontinuity‐capturing operators, are also discussed for both types of discretization. Results illustrating the quality of the stabilized solutions and the advantages of using the edge‐based approach are presented at the end of the paper. Copyright © 2001 John Wiley & Sons, Ltd.
Absorbing boundary condition on elliptic boundary for finite element analysis of water wave diffraction by large elongated bodies
Authors: Bhattacharyya Subrata Kumar , Sathyapal Santhosh , Vendhan Chiruvai P.
Published: August 2002

In a domain method of solution of exterior scalar wave equation, the radiation condition needs to be imposed on a truncation boundary of the modelling domain. The Bayliss, Gunzberger and Turkel (BGT) boundary dampers of first‐ and second‐orders, which require a circular cylindrical truncation boundary in the diffraction‐radiation problem of water waves, have been particularly successful in this task. However, for an elongated body, an elliptic cylindrical truncation boundary has the potential to reduce the modelling domain and hence the computational effort. Grote and Keller [On non‐reflecting boundary conditions. Journal of Computational Physics 1995; 122: 231–243] proposed extension of the first‐ and second‐order BGT dampers for the elliptic radiation boundary and used these conditions to the acoustic scattering by an elliptic scatterer using the finite difference method. In this paper, these conditions are implemented for the problem of diffraction of water waves using the finite element method. Also, it is shown that the proposed extension works well only for head‐on wave incidence. To remedy this, two new elliptic dampers are proposed, one for beam‐on incidence and the other for general wave incidence. The performance of all the three dampers is studied using a numerical example of diffraction by an elliptic cylinder. Copyright © 2001 John Wiley & Sons, Ltd.
Practical techniques for a three‐dimensional FEM analysis of incompressible fluid flow contained with slip walls and a downstream tube bundle
Authors: Eguchi Yuzuru
Published: August 2002

Two practical techniques are proposed in this paper to simulate a flow contained in a plenum with a downstream tube bundle under a PC environment. First, a technique to impose slip wall conditions on smooth‐faced planes and sharp edges is proposed to compensate for the mesh coarseness relative to boundary layer thickness. In particular, a new type of Poisson equation is formulated to simultaneously satisfy both such velocity boundary conditions on walls and the incompressibility constraint. Second, a numerical model for a downstream tube bundle is proposed, where hydraulic resistance in a tube is imposed as a traction boundary condition on a fluid surface contacting the tube bundle end. The effectiveness of the techniques is numerically demonstrated in the application to a flow in a condenser water box. Copyright © 2001 John Wiley & Sons, Ltd.
Large eddy simulation of turbulent flows by a least‐squares finite element method
Authors: Ding Xu , Tsang Tate T.H.
Published: August 2002

The least‐squares finite element method (LSFEM) based on first‐order formulations of governing equations has been used successfully for incompressible and compressible flows and transport processes. It has not been applied to turbulent flows. In this work, large eddy simulation (LES) with dynamic subgrid‐scale models is used to simulate turbulent flows. The LSFEM is implemented to solve the filtered LES equations for turbulent flows and transport processes. Numerical experiments have been carried out for three types of turbulent flows, turbulent channel flow, transitional recirculating flow, and thermal convective turbulent flow. Numerical results are compared with experimental data or direct numerical simulation results. Copyright © 2001 John Wiley & Sons, Ltd.
A domain decomposition approach to finite volume solutions of the Euler equations on unstructured triangular meshes
Authors: Dolean Victoria , Lanteri Stéphane
Published: August 2002

We report on our recent efforts on the formulation and the evaluation of a domain decomposition algorithm for the parallel solution of two‐dimensional compressible inviscid flows. The starting point is a flow solver for the Euler equations, which is based on a mixed finite element/finite volume formulation on unstructured triangular meshes. Time integration of the resulting semi‐discrete equations is obtained using a linearized backward Euler implicit scheme. As a result, each pseudo‐time step requires the solution of a sparse linear system for the flow variables. In this study, a non‐overlapping domain decomposition algorithm is used for advancing the solution at each implicit time step. First, we formulate an additive Schwarz algorithm using appropriate matching conditions at the subdomain interfaces. In accordance with the hyperbolic nature of the Euler equations, these transmission conditions are Dirichlet conditions for the characteristic variables corresponding to incoming waves. Then, we introduce interface operators that allow us to express the domain decomposition algorithm as a Richardson‐type iteration on the interface unknowns. Algebraically speaking, the Schwarz algorithm is equivalent to a Jacobi iteration applied to a linear system whose matrix has a block structure. A substructuring technique can be applied to this matrix in order to obtain a fully implicit scheme in terms of interface unknowns. In our approach, the interface unknowns are numerical (normal) fluxes. Copyright © 2001 John Wiley & Sons, Ltd.
A high resolution upwind scheme for multi‐component flows
Authors: Igra D. , Takayama K.
Published: August 2002

Conservative schemes usually produce non‐physical oscillations in multi‐component flow solutions. Many methods were proposed to avoid these oscillations. Some of these correction schemes could fix these oscillations in the pressure profile at discontinuities, but the density profile still remained diffused between the two components. In the case of gas–liquid interfaces, density diffusion is not acceptable. In this paper, the interfacial correction scheme proposed by Cocchi et al. was modified to be used in conjunction with the level‐set approach. After each time step two grid points that bound the interface are recalculated by using an exact Riemann solver so that pressure oscillations and the density diffusion at discontinuities were eliminated. The scheme presented here can be applied to any type of conservation law solver. Some examples solved by this scheme and their results are compared with the exact solution when available. Good agreement is obtained between the present results and the exact solutions. Copyright © 2002 John Wiley & Sons, Ltd.
Hedging in Incomplete Markets: An Approximation Procedure for Practical Application
Authors: Breuer Wolfgang , Gürtler Marc
Published: August 2002

Derivative financial instruments are frequently used as a tool for influencing the risk of entrepreneurial uncertain payoff. To this end, an approximation procedure is developed capable of calculating the optimal quantity of derivatives to be used. It is assumed that the entrepreneurial cash flow is governed by several stochastic factors and that derivatives are only available as a hedging tool for one of these factors. In general, it is easy to determine optimal hedging payment structures with respect to this factor, but real‐life hedging opportunities will typically not allow to perfectly reproduce such a fictitious payment structure, thus leading to complex numerical optimization problems. Instead of directly approximating the entrepreneurial expected utility maximum, we suggest using the fictitious optimal hedging payment structure as a starting point and to minimize the quadratic deviation between payment structures realizable by financial derivatives actually available and the resulting entrepreneurial payoff achieving the fictitious optimal hedging payment structure. This approach proves to be rather easy. Indeed, under certain conditions an explicit solution can be reached. After analyzing the qualitative properties of our approximation solution, we examine its efficiency for two practical hedging problems. In the first example, we get nearly the same solutions with our approximation procedure as with a grid programming approach presented by some other authors. Among other things, our second example may explain why some special kinds of financial derivatives, known as shared currency option under tenders, are not used in international invitations for tenders even though they offer hedging opportunities that are otherwise not available. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21: 599–631, 2001
Differential involvement of the hypermethylator phenotype in hereditary and sporadic colorectal cancers with high‐frequency microsatellite instability
Authors: Yamamoto Hiroyuki , Min Yongfen , Itoh Fumio , Imsumran Arisa , Horiuchi Shina , Yoshida Mio , Iku Shouhei , Fukushima Hiroshi , Imai Kohzoh
Published: August 2002

High‐frequency microsatellite instability (MSI‐H) due to defective DNA mismatch repair occurs in the majority of hereditary nonpolyposis colorectal cancers (HNPCCs) and in a subset of sporadic malignant tumors. Clinicopathologic and genotypic features of MSI‐H colorectal tumors in HNPCC patients and those in sporadic cases are very similar but not identical. Correlation between the MSI phenotype and aberrant DNA methylation has been highlighted recently. A strong association between MSI and CpG island methylation has been well characterized in sporadic colorectal cancers with MSI‐H but not in those of hereditary origin. To address the issue, we analyzed hereditary and sporadic colorectal cancers for aberrant DNA methylation of target genes using methylation‐specific polymerase chain reaction. DNA methylation of the MLH1, CDKN2A, MGMT, THBS1, RARB, APC, and p14ARF genes was found in 0%, 23%, 10%, 3%, 73%, 53%, and 33% of 30 MSI‐H cancers in HNPCC patients and in 80%, 55%, 23%, 23%, 58%, 35%, and 50% of 40 sporadic colorectal cancers with MSI‐H, respectively. Cases showing methylation at three or more loci of six genes other than MLH1 were defined as CpG island methylator phenotype–positive (CIMP+), and 23% of HNPCC tumors and 53% of sporadic cancers with MSI‐H were CIMP+ (P = 0.018). Differences in the extent of CpG island methylation, coupled with the differential involvement of several genes by methylation, in HNPCC tumors and sporadic MSI‐H colorectal cancers may be associated with diverging developmental pathways in hereditary and sporadic cancers despite similar MSI‐H phenotypes. © 2002 Wiley‐Liss, Inc.
Late‐appearing MLL rearrangement arising as a secondary change in adult acute myeloid leukemia
Authors: Rowe David , Breese Gareth J. , Lennard Anne , Bown Nick
Published: August 2002

Rearrangements of MLL are regarded as primary oncogenic events in acute leukemia. We report the case of a patient with acute myeloid leukemia with a complex abnormal karyotype at diagnosis who showed a putative stem line with monosomy 5 and a rearrangement of chromosome 17 as the only abnormalities and an evolved clone with an additional t(7,16,11)(p1?4;p13;q23) after treatment. Fluorescence in situ hybridization analysis confirmed that the translocation had resulted in an MLL rearrangement not present in the stem line or in the complex clones found at diagnosis. To date, this is the first report of an MLL rearrangement evolving as a secondary abnormality within a preexisting leukemic clone. © 2002 Wiley‐Liss, Inc.
Genome profiling of breast cancer cells selected against in vitro shows copy number changes
Authors: Kleivi Kristine , Lothe Ragnhild A. , Heim Sverre , Tsarouha Haroula , Kraggerud Sigrid M. , Pandis Nikos , Papadopoulou Anna , Andersen Johan , Jakobsen Kjetill S. , Teixeira Manuel R.
Published: August 2002

About 20% of breast carcinomas show no clonal chromosome abnormalities when analyzed after short‐term culturing. An interesting question is whether this subset of breast carcinomas really is karyotypically normal or if selection for normal cells occurred in vitro. To address this issue, 26 breast carcinomas that had shown no cytogenetic changes by chromosome banding analysis were examined by comparative genomic hybridization (CGH), a technique that does not require culturing or tumor metaphase cells. All but one case showed copy number changes by CGH (median, four). A comparison of these findings with those of a karyotypically abnormal series analyzed using the same CGH protocol found that the cytogenetically “normal” cases were typically genetically less complex (median, four and eight, respectively; P = 0.0058). Although largely the same alterations were found in both series, some differences with respect to the frequencies of specific imbalances were seen. Gains of 3p and 6q and losses of 10q, 14q, and 17p more often were found in the cytogenetically abnormal series than in the normal tumors. We conclude that in most instances cells found to be normal by chromosome banding analysis after short‐term culture do not belong to the tumor parenchyma. Furthermore, when we compared the distribution of the number of imbalances detected by CGH in the total data set according to the mitotic index in vivo (scored from 1 to 3), the median values were three, seven, and 18, respectively (P < 0.001). These data indicate not only that karyotypically normal breast carcinomas may represent a genetically simpler subgroup that grows poorly in vitro but also that this subset of tumors already has a slow growth rate in vivo. © 2002 Wiley‐Liss, Inc.
Novel alternative PBX3 isoforms in leukemia cells with distinct interaction specificities
Authors: Milech Nadia , Kees Ursula R. , Watt Paul M.
Published: August 2002

PBX3 is a member of the PBX family of TALE homeobox genes. The prototypic member, PBX1, was first identified in chromosomal translocations in B‐lineage leukemia and is required for normal hematopoiesis. PBX2 and PBX3 were later identified as members of this highly conserved family by their strong homology to PBX1. While the expression pattern of PBX1 is restricted, PBX2 and PBX3 are ubiquitously expressed. Little is known about the functional role of PBX3. Our studies identified two PBX3 transcripts alternative to the canonical forms, PBX3A and PBX3B, resulting from a novel splice in PBX3. These new isoforms, named PBX3C and PBX3D, have been detected in all tissues and cell lines tested. Intriguingly, expression of PBX3D is favored in normal cells, whereas PBX3C expression is favored in leukemia cells. Functional studies showed that PBX3C and PBX3D proteins were unable to interact with the PBX‐interacting factor PREP1 and weakly interacted with MEIS proteins. We propose that PBX3C and PBX3D may affect PBX3‐mediated transcriptional regulation by acting in opposition to the known PBX proteins through alternative PBX3 complex formation. The identification and characterization of these novel PBX3 isoforms provide a foundation for a better understanding of the biological role of PBX3. © 2001 Wiley‐Liss, Inc.
Identification of chromosomal deficiencies that modify Drosophila mastermind mutant phenotypes
Authors: Yedvobnick Barry , Helms Whitney , Barrett Britt
Published: August 2002

Summary: Mastermind (Mam) is a component of Notch pathway signaling. In combination with the intracellular domain of Notch and Suppressor of Hairless, Mam forms a transcriptional activation complex. We have initiated a genetic approach to identify other loci involved in Mam function. The screen utilizes engineered mutations in Mam that derive from GAL4‐UAS‐directed expression of dominant negative constructs. When driven at the wing margin, truncated versions of Mam phenocopy Notch pathway mutations. Correlated with these phenotypes is depression of Notch pathway target expression. Strains expressing truncated versions of Mam were tested for genetic interactions with a large collection of chromosomal deficiencies. Genomic segments that enhanced and suppressed the dominant wing phenotype were identified. These regions may contain uncharacterized loci involved in Notch pathway function. genesis 30:250–258, 2001. © 2001 Wiley‐Liss, Inc.
Multipoint development of the weighted pairwise correlation (WPC) linkage method for pedigrees of arbitrary size and application to the analysis of breast cancer and alcoholism familial data
Authors: Zinn‐Justin Anne , Ziegler Andreas , Abel Laurent
Published: August 2002

The weighted pairwise correlation (WPC) method is a simple and powerful model‐free method of linkage analysis that has the advantages of being applicable to binary, ordered categorical, quantitative, or censored traits, and to consider all pairs of relatives in large pedigrees. The originally implemented approach was limited to the use of the identical by state (IBS) information, and we recently extended the WPC method to incorporate the identical by descent (IBD) information for two‐point linkage analysis. Here, we develop a multipoint WPC method suitable for pedigrees of arbitrary size and large number of markers. The multipoint IBD estimation procedure for relative pairs is based on the efficient regression approach developed for pedigrees implemented in SOLAR. A robust and fast Monte‐Carlo procedure is used to determine reliable P values. Application of the method to the 214 pedigrees from the Breast Cancer Linkage Consortium provided for the Genetic Analysis Workshop (GAW) 9 shows that multipoint WPC statistic values were not far from two‐point maximum lod‐score values obtained by the classical parametric linkage method and were higher than multipoint variance component analysis lod‐scores obtained with SOLAR. The multipoint WPC method is also used to analyze the familial Collaborative Study of the Genetics of Alcoholism data on alcoholism released for GAW11. It allows a better specification of the linkage results previously obtained within the chromosome 4 region. Genet. Epidemiol. 21:40–52, 2001. © 2001 Wiley‐Liss, Inc.
A unified framework for transmission‐disequilibrium test analysis of discrete and continuous traits
Authors: Liu Ying , Tritchler David , Bull Shelley B.
Published: August 2002

This paper presents a unified framework for transmission‐disequilibrium tests for discrete and continuous traits. A conditional score test is derived that maximizes power to detect small effects for any exponential family distribution, which includes binary and normal distributions, and distributions that are skewed or have non‐normal kurtosis. The specific distributional form need not be specified, and the method applies to sibships of arbitrary size. Formulas for the distribution of the test statistic are given for models including complex genetic effects (additive, dominant, and recessive gene action), covariates, multiple gene models including gene‐gene interactions or heterogeneity, and gene‐environment interactions. We develop refinements of our method for trait‐based sampling designs and multiple siblings that can have dramatic effects on power. Genet. Epidemiol. 22:26–40, 2002. © 2002 Wiley‐Liss, Inc.
Differential gene expression in astrocytes from human normal and glaucomatous optic nerve head analyzed by cDNA microarray
Authors: Hernandez M. Rosario , Agapova Olga A. , Yang Ping , Salvador‐Silva Mercedes , Ricard Cynthia S. , Aoi Shun
Published: August 2002

Recent advances in cDNA microarray technology have made it possible to analyze expression of several thousand genes at the same time. Using this technique, gene expression in human astrocytes cultured from glaucomatous and normal optic nerve heads (ONH) was compared. One hundred‐fifty genes were differentially expressed more than 5‐fold in glaucomatous cell cultures compared with normal. These genes are involved in a number of biological processes, including signal transduction, cell adhesion and proliferation, ECM synthesis, and degradation. Confirmation of differential gene expression was performed by quantitative RT‐PCR. Western blots and immunohistochemistry demonstrated gene products in cell cultures or in human ONH tissues. Proliferation, adhesion and migration assays tested physiological responses suggested by differential gene expression. Our study suggests that cultured glaucomatous ONH astrocytes retain in culture many phenotypic characteristics that may be relevant to their role in the pathogenesis of glaucoma and, in general to reactive astrocytes in the CNS. Potential applications of these data include the identification and characterization of signaling pathways involved in astrocyte function, studies of the role of steroid‐metabolizing enzymes in the glaucomatous ONH, and further exploration of the role of selected identified genes in experimental animal and in vitro models of glaucoma. GLIA 38:45–64, 2002. © 2002 Wiley‐Liss, Inc.
Characterization of a synaptiform transmission between a neuron and a glial cell in the leech central nervous system
Authors: Britz Frank C. , Lohr Christian , Schmidt Joachim , Deitmer Joachim W.
Published: August 2002

The cross‐talk between neurons and glial cells is receiving increased attention because of its potential role in information processing in nervous systems. Stimulation of a single identifiable neuron, the neurosecretory Leydig interneuron in segmental ganglia of the leech Hirudo medicinalis, which modulates specific behaviors in the leech, evokes membrane hyperpolarization directly in the giant glial cell (Schmidt and Deitmer. Eur J Neurosci 11:3125–3133, 1999). We have studied the neuron‐to‐glia signal transmission in the voltage‐clamped giant glial cell to determine whether this interaction exhibits properties of a chemical synapse. The glial response had a mean latency of 4.9 s and was dependent on the action potential frequency; the glial cell responded to as few as five Leydig neuron action potentials in 50% of the trials. The glial current was sustained for minutes during repetitive Leydig neuron activity without any sign of desensitization. The current was sensitive to tetraethylammonium, and its reversal potential of −78 mV shifted with the external K+ concentration. The glial response increased with the duration of the neuronal action potentials and was sensitive to the external Ca2+/Mg2+ concentration ratio. The results suggest that Leydig neuron activity leads to a Ca2+‐dependent release of transmitter from the neuronal dendrites, evoking an K+ outward current in the giant glial cell, implying a synapse‐like transmission between a neuron and a glial cell. GLIA 38:215–227, 2002. © 2002 Wiley‐Liss, Inc.
An immortalized jimpy oligodendrocyte cell line: Defects in cell cycle and cAMP pathway
Authors: Feutz Anne Catherine , Pham‐Dinh Danielle , Allinquant Bernadette , Miehe Monique , Ghandour M. Said
Published: August 2002

Normal and jimpy oligodendrocytes in secondary cultures were transfected with plasmids containing the SV40 T‐antigen gene expressed under the control of the mouse metallothionein‐I promoter. Two immortalized stable cell lines, a normal (158N) and jimpy (158JP) cell line, expressed transcripts and proteins of oligodendrocyte markers, including proteolipid protein (PLP), myelin basic protein (MBP), and carbonic anhydrase II (CAII). Galactocerebroside and sulfatide were also detected with immunocytochemistry. Immunoelectron microscopy using gold particles showed that the truncated endogenous jimpy PLP was distributed throughout the cytoplasm and in association with the plasma membrane of cell bodies and processes. The length of the cell cycle in the jimpy oligodendrocytes in the absence of zinc was 31 h, about a 4‐h longer cell cycle than the normal line. In the presence of 100 μM zinc, the cell cycle became 3 h shorter for both cell lines, with the jimpy cell cycle duration remaining 4 h longer than the normal line. Interestingly, the jimpy cell line showed a significant deficiency in stimulation via the cAMP pathway. While the level of oligodendrocyte markers (PLP, MBP, and CAII) were significantly increased by dibutyryl cAMP (dbcAMP) treatment in the normal cell line, no changes were observed in the jimpy cell lines. This observation, together with previous results showing jimpy oligodendrocyte's failure to respond to basic fibroblast growth factor (bFGF), suggests a role for PLP in a signal transduction pathway. Jimpy and normal oligodendrocytes transfected with the SV40T antigen gene, driven by the wild‐type promoter of mouse metallothionein‐I, continue to express properties of oligodendrocytes and therefore provide a powerful model to explore the function of myelin proteins and to dissect the complexity of the jimpy phenotype. GLIA 34:241–252, 2001. © 2001 Wiley‐Liss, Inc.
SpL201: A conditionally immortalized Schwann cell precursor line that generates myelin
Authors: Lobsiger Christian S. , Smith Peter M. , Buchstaller Johanna , Schweitzer Beat , Franklin Robin J.M. , Suter Ueli , Taylor Verdon
Published: August 2002

Dramatic progress has been made over recent years toward the elucidation of the mechanisms regulating lineage determination and cell survival in the developing peripheral nervous system. However, our understanding of Schwann cell development is limited. This is partly due to the difficulties in culturing primary Schwann cell precursor cells, the earliest developmental stage of the Schwann cell lineage defined to date. Both the inability to maintain cultured Schwann cell precursor cells in an undifferentiated state and the technical difficulties involved in their isolation have hampered progress. We have conditionally immortalized rat Schwann cell precursor cells using a retrovirally encoded EGFR/neu fusion protein to circumvent these problems and to generate a source of homogeneous cells. The resulting SpL201 cell line expresses p75 and nestin, two proteins expressed by neural crest‐derived cells, as well as peripheral myelin protein 22, protein zero, and Oct‐6 as markers of the Schwann cell lineage. When cultured in EGF‐containing medium, the SpL201 cells proliferate and maintain an undifferentiated, Schwann cell precursor cell‐like state. The cell line is dependent on EGF for survival but can differentiate into early Schwann cell‐like cells in response to exogenous factors. Like primary rat Schwann cells, SpL201 cells upregulate Oct‐6 and myelin gene expression in response to forskolin treatment. Furthermore, the SpL201 cell line can form myelin in the presence of axons in vitro and is capable of extensively remyelinating a CNS white matter lesion in vivo. Thus, this cell line provides a valuable and unique tool to study the Schwann cell lineage, including differentiation from the Schwann cell precursor cell stage through to myelination. GLIA 36:31–47, 2001. © 2001 Wiley‐Liss, Inc.
Expression of 27 kDa heat shock protein (Hsp27) in immature rat brain after a cortical aspiration lesion
Authors: Sanz Olga , Acarin Laia , González Berta , Castellano Bernardo
Published: August 2002

The 27 kDa heat shock protein (Hsp27) is a well‐known member of the astroglial response to injury, playing a protective role against oxidative stress, apoptosis, and cytoskeletal destruction. Although several studies have been focused on the damaged adult brain, little is known about Hsp27 expression in the immature brain. In this work, we have examined the spatiotemporal pattern of Hsp27 expression in the normal postnatal rat brain following a cortical aspiration lesion at postnatal day 9. In the immature brain, Hsp27 is mainly observed in the internal capsule, although some scattered cells are also found in the ependyma, the corpus callosum, the septum, and hypothalamic glia limitans. In the internal capsule, Hsp27 expression is developmentally regulated, being significantly decreased from postnatal day 14. After a cortical aspiration lesion, de novo expression of Hsp27 is observed in cortical injured areas as well as in the secondary affected thalamus. In the cortex, expression of Hsp27 is first seen at day 1 postlesion (PL) surrounding the neurodegenerative area, becoming restricted to the glial scar at longer survival times. Although a pulse‐like expression of Hsp27 is observed in some microglial cells at day 1 PL, most Hsp27‐labeled cells are reactive astrocytes, which show GFAP overexpression and coexpress vimentin from day 3 PL. In the thalamus, astroglial Hsp27 expression is delayed, being first observed at day 5 PL. Thalamic Hsp27‐labeled astrocytes do not show vimentin expression. Our observations demonstrate astroglial expression of Hsp27 in areas of tissue damage following postnatal traumatic injury, suggesting an involvement of this cytoskeleton‐stabilizing protein in the remodeling processes following postnatal brain damage. GLIA 36:259–270, 2001. © 2001 Wiley‐Liss, Inc.
Olfactory receptor axons influence the development of glial potassium currents in the antennal lobe of the moth Manduca sexta
Authors: Lohr Christian , Oland Lynne A. , Tolbert Leslie P.
Published: August 2002

In the olfactory (antennal) lobe of the moth Manduca sexta, olfactory receptor axons strongly influence the distribution and morphology of glial cells. In the present study, we asked whether the development of the electrophysiological properties of the glial cells is influenced by the receptor axons. Whole‐cell currents were measured in antennal lobe glial cells in acute brain slices prepared from animals at different stages of metamorphic development (stages 3, 6, and 12). Outward currents were induced by depolarizing voltage steps from a holding potential of −70 mV. At all developmental stages investigated, the outward currents were partly blocked by bath application of the potassium channel blocker 4‐aminopyridine (4AP, 10 mM) or by including tetraethylammonium (TEA, 30 mM) in the pipette solution. The relative contribution of the 4AP‐sensitive current to the outward current increased from 18% at stages 3 and 6 to 42% at stage 12, while the TEA‐sensitive current increased from 18% at stage 3 to 81% at stage 6, and then declined again to 40% at stage 12. In contrast, in the absence of receptor axons, these changes in the contribution of the TEA‐ and 4AP‐sensitive currents to the total outward current did not occur; rather, the current profile remained in the most immature state (stage 3). The results suggest that olfactory receptor axons are essential for development of the mature pattern of glial potassium currents. GLIA 36:309–320, 2001. © 2001 Wiley‐Liss, Inc.
Depression in the community dwelling elderly: Do clinical and sociodemographic factors influence referral to psychiatry?
Authors: Eustace A. , Denihan A. , Bruce I. , Cunningham C. , Coakley D. , Lawlor B. A.
Published: August 2002

Background

Little is known about the reasons why depressed elderly patients are referred to the old age psychiatric services. Reasons for referral of depressed younger patients have been clarified however they may not be generalisable to an older population.

Objectives

The purpose of this study is to examine which clinical and sociodemographic factors influence referral of patients with late life depression from primary care.

Methods

Twenty‐eight people were identified with depression in a day hospital referred by their general practitioner. These were compared with fifty‐two people with depression in the community who had not been referred to the psychiatric services.

Results

Having a more severe depression (p = 0.0016) and having co‐morbid anxiety (p = 0.0017) meant you were more likely to be referred to the day hospital. Gender did not appear to influence referral from general practitioners.

Conclusions

It appears that severity of depression and having higher levels of anxiety make it more likely that you will be referred by your general practitioner to the old age psychiatry services. Copyright © 2001 John Wiley & Sons, Ltd.
Estrogen replacement therapy is associated with less progression of subclinical structural brain disease in normal elderly women: a pilot study
Authors: Cook Ian A. , Morgan Melinda L. , Dunkin Jennifer J. , David Steven , Witte Elise , Lufkin Robert , Abrams Michelle , Rosenberg Susan , Leuchter Andrew F.
Published: August 2002

Background

Cortical atrophy, central atrophy, deep white‐matter hyperintensities, and periventricular hyperintensities are reported in normal aging.

Objectives

We examined the effects of estrogen replacement therapy (ERT) on these forms of ‘subclinical structural brain disease’ (SSBD) in normal, postmenopausal women in a pilot, naturalistic, longitudinal study of 15 subjects.

Methods

Two assessments were performed at least two years apart, with volumetric magnetic resonance imaging (MRI) and neuropsychological testing.

Results

Women receiving open‐label ERT showed significantly less progression of SSBD than those who did not.

Conclusions

The association between reduced SSBD progression and ERT suggests this intervention could help preserve normal brain structure in healthy elderly women. Copyright © 2002 John Wiley & Sons, Ltd.
Phosphorylation of 2‐(3‐methyl‐1,3‐diazabuten‐1‐yl)‐3‐ethoxycarbonylthiophenes with phosphorus(III) halides
Authors: Pinchuk Alexandr M. , Kovalyova Svetlana A. , Ivonin Sergey P. , Merkulov Anatoliy S. , Kudrya Tamara N. , Chaikovskaya Alexandra A. , Tolmachev Andrey A.
Published: August 2002

2‐(3‐Methyl‐1,3‐diazabuten‐1‐yl)‐3‐ethoxycarbonylthiophenes are phosphorylated with phosphorus(III) halides in basic media at position 5 of the thiophene ring. Up to three heteroaromatic substituents can be introduced one by one at the same phosphorus atom. On this basis, mono‐, bis‐, and trishetaryl substituted P(III) and P(V) derivatives have been obtained. Phosphorylated 2‐(N,N‐dimethylformamidino)‐3‐ethoxycarbonylthiophenes provide a synthetic access to phosphorylated thienopyrimidines. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:641–651, 2001
Thiofenchone s‐methylide and its spiro‐1,3,4‐thiadiazoline precursor
Authors: Huisgen Rolf , Mloston Grzegorz , Pröbstl Albert
Published: August 2002

Spiro[fenchane‐2,2′‐(1,3,4)‐thiadiazoline] (6), prepared from thiofenchone and diazomethane, extrudes N2 (t1/2 22 min, 46°C, toluene) and furnishes the S‐methylide 7 which, in turn, closes the thiirane ring or else is intercepted by 1,3‐cycloadditions to dipolarophiles (tetracyanoethylene, maleic anhydride, N‐methyl‐1,2,4‐triazoline‐3,5‐dione, aromatic thioketones). When thiocarbonyl S‐methylide 7 is set free in methanol, fenchone S,O‐dimethylacetal is formed as an HX adduct. Catalysis by acetic acid converts 7 to 1‐(methylthio)‐α‐fenchene (25) by way of a Wagner‐Meerwein rearrangement. The addition of diazomethane to thiocampher leads, via thiadiazoline 12, to thiocamphor S‐methylide; the latter undergoes a 1,4‐H shift, thus affording 2‐methylthio‐2‐bornene (11). © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:136–145, 2001
The structures of diphenyl(diphenylsulfimido)(nitrido)sulfur(VI) and diphenyl(diphenyl‐sulfodiimido)(nitrido)sulfur(VI), Ph2(X)S=N–(Ph2)S≡N (X = lone pair, NH)
Authors: Fujii Takayoshi , Fujimori Teruyoshi , Miyoshi Shin , Murotani Satoru , Ohkubo Masanori , Yoshimura Toshiaki
Published: August 2002

The crystal structures of diphenyl(diphenylsulfimido)(nitrido)sulfur(VI) (Ph2S=N–(Ph2)S≡N) (1) and diphenyl(diphenylsulfodiimido)(nitrido)sulfur(VI) (Ph2(HN=)S=N–(Ph2)S≡N) (2) were determined by X‐ray crystallographic analysis. The former has a bent S–N–S unit with bridging S–N bond lengths of 1.651(1) and 1.622(1) Å and terminal S–N bond lengths of 1.467(1) Å; the latter compound possesses approximately a u‐shaped N–S–N–S–N unit with bridging S–N bond lengths of 1.653(2) and 1.576(2) Å, and terminal S–N bond lengths of 1.456(2) and 1.515(2) Å. Single‐point ab initio calculations were also carried out using the data from the crystal structures of 1 and 2. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:263–268, 2001
Facile synthesis of a chiral auxiliary bearing the isocyanide group
Authors: Ilankumaran Palanichamy , Kisanga Philip , Verkade John G.
Published: August 2002

The synthesis of a chiral isocyanide possessing the easily cleaved menthoxy group is reported. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:561–562, 2001
Reactions of 5‐methylene‐1,3‐thiazolidine‐2‐thione and 5‐methylene‐2‐oxazolidinone with isocyanates catalyzed by bases
Authors: Shi Min , Shen Yu‐Mei
Published: August 2002

5‐Methylene‐1,3‐thiazolidine‐2‐thione and 5‐methylene‐2‐oxazolidinone can react with isocyanates to give the corresponding condensed urethanes in high yields in the presence of organic or inorganic bases under mild reaction conditions. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:610–616, 2001
Bonding in the Si2H2 isomers: A topographical study
Authors: Chesnut D. B.
Published: August 2002

Chemical bonding in the isomers of the formally triply bonded Si2H2 system are studied from the point of view of electron localization function (ELF) bond basin populations and atoms‐inmolecules (AIM) delocalization indices. Calculation carried out at the B3LYP/6‐31 + G(d,p) and MP2 (FC)/6‐31 + G(d,p) level leads to ELF topographies and basin populations that are in good agreement with our intuitive chemical pictures of bonding in these molecules. One single, two double, and one triple siliconsilicon bonds are found in the four isomers. It is shown that, with one AIM exception, ratios of basin populations and delocalization indices are consistent and useful in characterizing the nature of the chemical bonding involved. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:53–62, 2002; DOI 10.1002/hc.1106
Alternative approaches to obtain optimal bid values in contingent valuation studies and to model protest zeros. Estimating the determinants of individuals' willingness to pay for home care services in day case surgery
Authors: Dalmau‐Matarrodona Eulàlia
Published: August 2002

The use of day case surgery has increased rapidly as an alternative to inpatient surgery. Little is known, however, about the value of day case surgery to patients. The aim of this paper was to develop a contingent valuation survey to investigate how individuals value the costs of shifting from inpatient to day case surgery based on home care services. Using the willingness to pay (WTP) approach, two kinds of sequential experiments are compared: the maximum likelihood recursion (MLR) method and the C‐optimal sequential procedure. The goal of sequential experimentation is to find bid values that provide the maximum possible information about the parameters of the WTP distribution, especially when the sample size is small. The C‐optimal sequential procedure is shown to be an improvement, in terms of the statistical precision in small samples, over the MLR method. In addition, the paper presents a double hurdle (DH) approach for modelling the determinants of individuals' WTP. Using data from a contingent valuation survey conducted in 1996 on patients selected from the Day Case Surgery Unit in a hospital in the region of Catalonia, we argue that participation in the market offered and the level of consumption, that is, people's WTP, should be treated as individual choices. The results show that income and sex are related to WTP. Also, in this study, a clear presence of starting‐point bias, introduced by the bid offered, was found. It is concluded that the WTP technique is potentially useful in evaluating health care programmes, although it is important to note that the criteria used to find an optimal design (in our model to minimize the asymptotic variance of the estimator used) may be restrictive from an economic point of view. Copyright © 2001 John Wiley & Sons, Ltd.
The use of brush cytology and directed biopsies for the detection of nasopharyngeal carcinoma and precursor lesions
Authors: Chang Alexander R. , Liang Xiao‐Man , Chan Anthony T. C. , Chan May K. M. , Teo Peter M. L. , Johnson Philip J.
Published: August 2002

Background

It has been proposed that nasopharyngeal carcinoma (NPC) has an early noninvasive stage, designated nasopharyngeal intraepithelial neoplasia (NPIN). Hence, the detection and treatment of NPIN will prevent NPC from developing, and this would be similar to the strategies used for cervical cancer prevention. We wanted to ascertain the feasibility of using a brush sampler to collect cells for the cytologic diagnosis of NPIN and NPC. If successful, the technique could be used as a screening test in endemic areas.

Methods

A disposable sampler (Uterobrush) was used to collect nasopharyngeal mucosal brushings from 546 patients for cytologic examination. After this, most patients had biopsies, and this allowed histologic‐cytologic correlation to be undertaken.

Results

In 528 patients (96.7%) there were satisfactory cytologic and biopsy specimens for evaluation. There were 149 cases with positive histology and 103 had positive cytology (specificity was 100% and the sensitivity was 69.1%). One case of NPC with concurrent NPIN was seen among the biopsy specimens, but no case of NPIN was detected cytologically.

Conclusions

The cytologic pickup of NPC was substantially lower than that obtained on biopsy. More importantly, NPIN was uncommon. Therefore, a screening test that depends on the collection of cells for the microscopic diagnosis of NPIN and NPC is unlikely to have a major impact on the incidence of NPC. Furthermore, obtaining a good cytologic specimen from the nasopharynx is not simple, and this further limits this technique for mass screening purposes. The concept of a cytologic test for NPC, similar to the Pap test for the prevention of uterine cervix cancer, has still to be realized. © 2001 John Wiley & Sons, Inc. Head Neck 23: 637–645, 2001.
Validation of the RTOG recursive partitioning classification for head and neck tumors
Authors: Cooper Jay S. , Berkey Brian , Marcial Victor , Fu Karen K. , Lee D. J.
Published: August 2002

Background

We previously demonstrated that a mathematical technique called recursive partitioning analysis (RPA), when applied to the Radiation Therapy Oncology Group Head and Neck Cancer database, created rules that formed subgroups (“classes”) having unique outcomes. We sought to learn if the application of RPA‐derived rules to a new head and neck database would create classes that were similarly associated with outcome and thereby validate this technique.

Methods

The rules derived from recursive partitioning analysis of the previous database were used to subgroup an independent, new head and neck cancer database (RTOG 85‐27), created as part of a phase III trial of the hypoxic‐cell radiosensitizer, Etanidazole. The resulting classes were compared with each other and with the classes formed from the previous database.

Results

The rules derived by RPA from our previous database correctly grouped the tumors in the new database into unique classes of similar outcome. RPA could successfully use either survival or local‐regional control of disease as the measure of outcome. As judged by comparison of the 95% confidence intervals, the outcome of the classes in the new database is essentially indistinguishable from the outcome of the classes in the previous database.

Conclusion

RPA‐derived rules provide a reliable method to assort head and neck tumors into unique classes that are predictive of outcome. These rules can be successfully applied to new databases that were not used in the creation of the rules and thereby validate the methodology. Head Neck 23: 669–677, 2001.
Hand–arm vibration in a group of hand‐operated grinding tools
Authors: Wasserman Donald E. , Hudock Stephen D. , Wasserman Jack F. , Mullinix Logan , Wurzelbacher Steven J. , Siegfried Karl V.
Published: August 2002

Vibration acceleration was triaxially and basicentrically measured, and digital‐audio‐tape‐recorded with each axis separately evaluated using both the ANSI S3.34 and ACGIH hand‐arm vibration (HAV) guidelines, for two pairs of pneumatic handheld grinders commonly used in metal fabrication operations including shipyards. Each tool pair consisted of a new and used grinder of the same model, performing the same simulated grinding tasks using new small grinding wheels, carbide burrs, wire brushes, and flap wheels. The results of this limited study showed, primarily, that the HAV standards were not exceeded, but there was a consistent tendency for the acceleration levels to increase between new and used tools, ranging from 11% to 66% on the Z‐axis, 13% to 66% on the Y‐axis, 44% to 58% on the X‐axis, when tasks involved using grinding wheels and carbide burrs (hard implements). The results were mixed when using disposable wire brushes and flap wheels (softer implements). The overall results suggest the need for and implementation of a regular tool vibration monitoring and maintenance program as a primary element to help maintain tool acceleration levels to a minimum. © 2002 Wiley Periodicals, Inc.