bluuebunny/crossref_metadata_2025 huggingface dataset:
Brand Name Audit Pricing, Industry Specialization, and Leadership Premiums post‐Big 8 and Big 6 Mergers*
Authors: Ferguson Andrew , Stokes Donald
Published: November 2003

This paper investigates brand name, industry specialization, and leadership audit pricing in the wake of the mergers that created the Big 6 and the Big 5 accounting firms. For samples of Australian listed public companies in each of the postmerger years 1990, 1992, 1994, and 1998, we estimate national audit fee premiums for the Big 6/5 auditors and the industry specialists and leaders. We find limited support for the ability of the Big 6/5 to obtain fee premiums over non‐Big 6/5 for those industries not having specialist auditors. Nonspecialist Big 6/5 auditors are able to obtain fee premiums over nonspecialist non‐Big 6/5 auditors for those industries having specialist auditors. However, this result only holds among the smaller half of our sample. We do not find strong support for the presence of industry specialist premiums in the postmerger years, especially after 1990, using various definitions of industry specialist. We find, at best, limited support for the presence of industry leadership premiums. The evidence suggests that after the Big 8/6 audit firm mergers, some caution is required in generalizing the Craswell, Francis, and Taylor 1995 finding of national market industry specialist premiums. More generally, the study raises questions about the tenuous link between the concept of specialization and national market‐share statistics.
Accounting Recognition, Moral Hazard, and Communication*
Authors: LIANG PIERRE JINGHONG
Published: November 2003

Two complementary sources of information are studied in a multiperiod agency model. One is an accounting source that partially but credibly conveys the agent's private information through accounting recognition. The other is an unverified communication by the agent (i.e., a self‐report). In a simple setting with no communication, alternative labor market frictions lead to alternative optimal recognition policies. When the agent is allowed to communicate his or her private information, accounting signals serve as a veracity check on the agent's self‐report. Finally, such communication sometimes makes delaying the recognition optimal. We see contracting and confirmatory roles of accounting as its comparative advantage. As a source of information, accounting is valuable because accounting reports are credible, comprehensive, and subject to careful and professional judgement. While other information sources may be more timely in providing valuation information about an entity, audited accounting information, when used in explicit or implicit contracts, ensures the accuracy of the reports from nonaccounting sources.
Cancellation of Executive Stock Options: Tax and Accounting Income Considerations*
Authors: Mawani Amin
Published: November 2003

Canadian firms face a trade‐off between reporting higher accounting income and paying lower taxes that arises from their ability to cancel in‐the‐money executive stock options and making a substitute cash payment to the executive instead of issuing shares. Firms' trade‐off hypotheses are operationalized in a multilateral framework and empirically tested using insider‐trading data. The multilateral approach is designed to control for the incentive effects of alternative compensation schemes and to determine the cancellation payment that keeps the executive indifferent between receiving cash or shares. The results show that firms consider both taxes and financial reporting costs in determining their option cancellation behavior.
Accounting Choices and Risk Management: SFAS No. 115 and U.S. Bank Holding Companies*
Authors: Hodder Leslie , Kohlbeck Mark , McAnally Mary Lea
Published: November 2003

This paper provides evidence that regulatory contracts affect firms' accounting choices and risk‐management decisions. Specifically, we investigate whether an exogenous shock to regulatory risk induced by Statement of Financial Accounting Standards No. 115, “Accounting for Certain Investments in Debt and Equity Securities” (SFAS 1993), encouraged U.S. banks to deviate from portfolio and risk benchmarks when they adopted the standard. Because we cannot observe relevant benchmarks, we model portfolio and risk decisions as functions of macroeconomic and firm‐specific factors using data from a period when regulatory capital was immune to SFAS No. 115 accounting. We examine a sample of 230 publicly traded banks and find that (1) irrespective of adoption timing, banks classified too few securities available for sale (AFS) relative to estimated benchmarks; (2) weaker banks that adopted the standard early classified far more securities as AFS relative to benchmarks; (3) banks altered the size of their securities portfolios along with the levels of interest‐rate risk and credit risk as regulatory capital decreased; and (4) the level of interest‐rate risk on banks' loan portfolios increased at the time of SFAS No. 115 adoption. We also explore the 1995 Financial Accounting Standards Board (FASB) amnesty when firms could “readopt” SFAS No. 115. We find that banks used the 1995 FASB amnesty to undo strategic initial SFAS No. 115 adoption decisions. Taken together, our findings suggest that SFAS No. 115 caused some of the accounting and economic consequences predicted by bankers, analysts, and academics.
The Differential Use of Information by Experienced and Novice Auditors in the Performance of Ill‐Structured Audit Tasks*
Authors: Earley Christine E.
Published: November 2003

The experiment reported in this paper tests a theoretical model of experienced and novice auditors' information use. The model, based on social cognition research, posits that when judgements are sequential, the information encountered first affects the processing of subsequent information. Specifically, initial information that is in line with expectations results in more superficial processing of subsequent information than initial information that violates expectations. The judgements of 13 experienced and 26 novice auditors were analyzed to determine whether the model is descriptive of auditors' judgements in an ill‐structured task setting (real estate valuation). Results lend support for the model. The implications of the results and the model's impact on audit effectiveness are discussed.
Sequential Solutions to Capacity‐Planning and Pricing Decisions*
Authors: Balakrishnan Ramji , Sivaramakrishnan K.
Published: November 2003

Ideally, firms should jointly solve capacity‐planning and product‐pricing problems. In practice, informational limitations and cognitive bounds may force firms to sequentially solve the two problems. For example, a firm may plan capacity using limited demand information, and update prices subsequently once additional demand information becomes available. In a simple setting, we characterize the economic loss due to such sequential planning. We use simulation experiments to assess the extent of this loss in more complex settings. We find a relatively low loss if the firm plans for capacity using limited demand information and subsequently adjusts product prices to reflect realized market conditions. However, even “reasonable” restrictions on the subsequent price adjustment (e.g., constraining adjusted prices to always exceed full cost) lead to significant economic loss.
Morphologic, karyotypic, and molecular evidence of a new form ofChiropotes(primates, pitheciinae)
Authors: Bonvicino C.R. , Boubli J.P. , Otazú I.B. , Almeida F.C. , Nascimento F.F. , Coura J.R. , Seuánez H.N.
Published: November 2003

Morphologic, karyotypic, and molecular analyses were carried out in 25 specimens of a distinct morph ofChiropotes(henceforth termedChiropotessp.) obtained from a number of localities in the Brazilian Amazon. Pelage coloration clearly distinguishes the collected specimens and all other known species of this genus. A distinct karyotype was described forChiropotessp. It differs fromC. satanas chiropotesby two pericentric inversions, and fromC. satanas utahickiby three, which suggests that these taxa are reproductively isolated. Morphometric analyses did not show significant differentiation between theseChiropotestaxa. Molecular analyses confirmed the monophyly of the subfamily Pitheciinae and generaChiropotes, Cacajao, andPithecia(the latter appearing as the most basal lineage of the pithecine clade). The genetic distances betweenC. s. utahickiandChiropotessp. from Rio Negro were greater than those between three recognized species ofPithecia, but smaller than those betweenCacajao calvusandCacajao melanocephalus. The most appropriate name forChiropotessp. from Rio Negro isC. israelita. This species,C. s. chiropotes, andC. s. utahickiare allopatric. Pelage coloration, karyotype, and molecular analysis strongly indicate thatC. chiropotes, C. utahicki, andChiropotes israelitadeserve species status. Am. J. Primatol. 61:123–133, 2003. © 2003 Wiley‐Liss, Inc.
Local heating of human skin by millimeter waves: A kinetics study
Authors: Alekseev S.I. , Ziskin M.C.
Published: November 2003

Heating rates of human skin exposed locally to 42.25 GHz mm waves, coming from a waveguide (WG) opening or a YAV device designed for therapeutic application, were studied in vivo using infrared (IR) thermography. For both radiators, the power density distribution was described by a circularly symmetrical Gaussian type function on the exposed skin surface. Insertion of a small thermocouple (d = 0.1 mm) in the exposed area did not produce any significant artifact, either in the power density distribution or kinetics measurement, providing it was perpendicular to the E vector. The heating kinetics in the skin exposed with either the WG opening or the YAV device were well fitted to solutions of the 2‐D bio‐heat transfer equation for homogeneous tissue. Changes in irradiating beam size (1–8 mm) had no detectable effect on the initial (0.3–3.0 s) phase of the heating kinetics. However, the amplitude of the kinetics decreased substantially with decreasing the beam size. As the temperature rise in the time interval necessary for reliable measurement of the initial temperature rise rate was very small, an accurate experimental determination of specific absorption rate (SAR) becomes practically impossible at the low intensities normally used in our experiments. The correct SAR values may be found from fitting of the model to the heating kinetics. Bioelectromagnetics 24:571–581, 2003. © 2003 Wiley‐Liss, Inc.
Bifurcation of burst response in an Amari‐Hopfield neuron pair with a periodic external force
Authors: Tsuji Shigeki , Ueta Tetsushi , Kawakami Hiroshi , Aihara Kazuyuki
Published: November 2003

To clarify the mechanism of the information processing in the brain of living organisms, and investigate information coding of a neuron, a reasonable mathematical model of a neuron is needed. Various models have been proposed and analyzed for now, some relationship between bursting response and bifurcations. In this paper, we propose a simple and effective model to realize bursting phenomena in Amari‐Hopfield coupled neurons. In this model, we can constructively design desirable bursting responses. Bifurcation diagrams and some analytical results are given, and a basic design scheme to generate a bursting is shown. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(2): 43–53, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10217
Investigation of VFT surges propagated into transformer and overvoltages applied to winding
Authors: Ishikawa Yasuhisa , Iwai Akihiko , Nishiwaki Susumu , Koshizuka Tadashi , Teranishi Tsuneharu , Uehara Kyouichi
Published: November 2003

Investigations were conducted on the VFT (Very Fast Transient) surges that propagate into a 500‐kV transformer. The disconnector restriking surge and ground fault surged were discussed. It was regarded that a large part of the surge voltage was applied just at the entrance of the transformer winding for the VFT surges. Thus, an equivalent circuit that models the windings was used for the analysis. The overvoltages that appear between the first winding sections at the entrance of the transformer were computed. The following was established. (1) The overvoltage between the first winding sections becomes greater when the magnitude of the voltage change at the transformer terminal is larger. The overvoltage between the first winding sections is not affected by the magnitude of the transformer terminal voltage. (2) For the disconnectors that are not connected directly to the transformer, the voltage change at the transformer terminal is not so large. (3) In the case of a ground fault at the GIS near the transformer, the voltage change at the transformer terminal is the same as that for a disconnector directly connected to the transformer. (4) In actual GIS, the disconnector that is connected directly to the transformer is not usually used. In this situation, the overvoltages that threaten the transformer insulation will not be generated by the restriking of the disconnectors. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(2): 20–26, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10225
High‐yield isolation of murine microglia by mild trypsinization
Authors: Saura Josep , Tusell Josep Maria , Serratosa Joan
Published: November 2003

Microglia can be isolated with high purity but low yield by shaking off loosely adherent cells from mixed glial cultures. Here we describe a new technique for isolating microglia with an average yield close to 2,000,000 microglial cells/mouse pup, more than five times higher than that of the shaking method. Confluent mixed glial cultures are subjected to mild trypsinization (0.05–0.12%) in the presence of 0.2–0.5 mM EDTA and 0.5–0.8 mM Ca2+. This results in the detachment of an intact layer of cells containing virtually all the astrocytes, leaving undisturbed a population of firmly attached cells identified as > 98% microglia. These almost pure microglial preparations can be kept in culture for weeks and show proliferation and phagocytosis. Treatment with macrophage colony‐stimulating factor and lipopolysaccharide, alone or in the presence of interferon γ, induces typical microglial responses in terms of proliferation, morphological changes, nuclear factor‐κB translocation, NO, and tumor necrosis α release and phagocytosis. This method allows for the preparation of highly enriched mouse or rat microglial cultures with ease and reproducibility. Because of its high yield, it can be especially convenient when high amounts of microglial protein/mRNA are required or in cases in which the starting material is limited, such as microglial cultures from transgenic animals. © 2003 Wiley‐Liss, Inc.
Coupling of astrocyte connexins Cx26, Cx30, Cx43 to oligodendrocyte Cx29, Cx32, Cx47: Implications from normal and connexin32 knockout mice
Authors: Nagy J.I. , Ionescu A.‐V. , Lynn B.D. , Rash J.E.
Published: November 2003

Oligodendrocytes in vivo form heterologous gap junctions with astrocytes. These oligodendrocyte/astrocyte (A/O) gap junctions contain multiple connexins (Cx), including Cx26, Cx30, and Cx43 on the astrocyte side, and Cx32, Cx29, and Cx47 on the oligodendrocyte side. We investigated connexin associations at A/O gap junctions on oligodendrocytes in normal and Cx32 knockout (KO) mice. Immunoblotting and immunolabeling by several different antibodies indicated the presence of Cx32 in liver and brain of normal mice, but the absence of Cx32 in liver and brain of Cx32 KO mice, confirming the specificity and efficacy of the antibodies, as well as allowing the demonstration of Cx32 expression by oligodendrocytes. Oligodendrocytes throughout brain were decorated with numerous Cx30‐positive puncta, which also were immunolabeled for both Cx32 and Cx43. In Cx32 KO mice, astrocytic Cx30 association with oligodendrocyte somata was nearly absent, Cx26 was partially reduced, and Cx43 was present in abundance. In normal and Cx32 KO mice, oligodendrocyte Cx29 was sparsely distributed, whereas Cx47‐positive puncta were densely localized on oligodendrocyte somata. These results demonstrate that astrocyte Cx30 and oligodendrocyte Cx47 are widely present at A/O gap junctions. Immunolabeling patterns for these six connexins in Cx32 KO brain have implications for deciphering the organization of heterotypic connexin coupling partners at A/O junctions. The persistence and abundance of Cx43 and Cx47 at these junctions after Cx32 deletion, together with the paucity of Cx29 normally present at these junctions, suggests Cx43/Cx47 coupling at A/O junctions. Reductions in Cx30 and Cx26 after Cx32 deletion suggest that these astrocytic connexins likely form junctions with Cx32 and that their incorporation into A/O gap junctions is dependent on the presence of oligodendrocytic Cx32. © 2003 Wiley‐Liss, Inc.
Limitrin, a novel immunoglobulin superfamily protein localized to glia limitans formed by astrocyte endfeet
Authors: Yonezawa Tomoko , Ohtsuka Aiji , Yoshitaka Teruhito , Hirano Shuichi , Nomoto Hiroyuki , Yamamoto Kiyotaka , Ninomiya Yoshifumi
Published: November 2003

We report the molecular cloning of a new member of the transmembrane‐type immunoglobulin superfamily and designate the encoded protein as limitrin, since it localized selectively to glia limitans in mouse brain. Limitrin cDNA was obtained using a subtractive hybridization procedure designed to identify molecules responsible for blood‐brain barrier function. Western blots using a limitrin‐specific antibody demonstrated that the gene product is expressed significantly in mouse brain and primary murine astrocytes and is distributed in the plasma membrane. Immunohistochemical studies using confocal and electron microscopy clearly demonstrated highly polarized localization in astroglial endfeet in the perivascular region and under the pia mater in vivo. Limitrin is expressed in the spinal cord and in many areas of the brain, but not in the median eminence or subfornical organ (the circumventricular organs), where the blood‐brain barrier is lacking. Disruption of the blood‐brain barrier by cold injury resulted in a drastic reduction in limitrin expression. Furthermore, during retrieval from cold injury, the increased expression of limitrin in perivascular endfeet correlated with the recovery of angiogenesis in capillaries within the lesion margins. Our results suggest that limitrin is physically and functionally associated with the blood‐brain barrier, implying that this protein may be useful as a diagnostic tool of barrier integrity. © 2003 Wiley‐Liss, Inc.
Oligodendrocyte process outgrowth in vitro is modulated by epigenetic regulation of cytoskeletal severing proteins
Authors: Liu Aixiao , Muggironi Michela , Marin‐Husstege Mireya , Casaccia‐Bonnefil Patrizia
Published: November 2003

Process outgrowth is crucial in oligodendrocyte (OL) development and myelination. It is well accepted that increased levels of proteins affecting the polymerization of cytoskeletal components promote branching. Interestingly, we have suggested that other mechanisms may contribute to oligodendrocyte process outgrowth. We have previously shown that pharmacological inhibitors of histone deacetylation prevent oligodendrocyte branching and we now seek to explore in detail the relationship between these two events. The results presented here indicate that pharmacological inhibitors of histone deacetylation prevent branching, similar to the effect of low doses of cytoskeletal depolymerizing agents. The lack of process outgrowth does not correlate with changes in the levels of tubulin or actin, but correlates with increased levels of microtubule (i.e., stathmin) and microfilaments (i.e., gelsolin) depolymerizing proteins. These data suggest that in OL progenitors, the high levels of depolymerizing proteins maintain a simple morphology, while branching is favored by reduced levels of these cytoskeletal components, consequent to the effect of histone deacetylation on gene expression. We therefore hypothesize that epigenetic regulation of stathmin and gelsolin is a novel regulatory mechanism contributing to OL process outgrowth. In conclusion, our results suggest that process outgrowth in vitro is regulated not only by increased levels of proteins affecting polymerization, but also by decreased levels of proteins affecting depolymerization. The levels of these severing proteins are regulated by chromatin modifiers and therefore suggest that their expression in developing OL is decreased by an epigenetic mechanism. © 2003 Wiley‐Liss, Inc.
The brain‐specific protein MLC1 implicated in megalencephalic leukoencephalopathy with subcortical cysts is expressed in glial cells in the murine brain
Authors: Schmitt Angelika , Gofferje Viktor , Weber Melanie , Meyer Jobst , Mössner Rainald , Lesch Klaus‐Peter
Published: November 2003

The human MLC1 gene (also known as KIAA0027 and WKL1) and its murine orthologue (Mlc1) encode a putative transmembrane protein expressed primarily in brain. Recessive mutations within human MLC1 cause megalencephalic leukoencephalopathy with subcortical cysts (MLC), whereas a missense mutation resulting in a methionine substitution within a transmembrane leucine string of MLC has been implicated in catatonic schizophrenia in a large pedigree. To gain insight into the function of the MLC protein and to elucidate the pathophysiology of these severe neurodegenerative disorders, information on the cellular and regional distribution of the murine Mlc1, as well as the developmental pattern of Mlc1 expression in brain, is required. Using in situ hybridization (ISH), Mlc1 mRNA was exclusively detected in glial cells of the adult murine brain, such as astrocytes, Bergmann glia, and ependymal cells. ISH, Northern blot analysis, and quantitative real‐time polymerase chain reaction (PCR) demonstrated that Mlc1 mRNA is broadly distributed in the adult mouse brain, with highest concentrations of expression in the cerebellum and olfactory bulb. Furthermore, differential expression patterns during brain development were revealed. Overall brain Mlc1 mRNA concentrations exhibited a substantial increase in the perinatal period reaching adult concentrations at postnatal day 5. At the cellular level, highest Mlc1 expression was found during the pre‐ and perinatal period in multipotential neural precursor cells, especially in the subventricular zone of the lateral ventricle, whereas in adulthood highest Mlc1 mRNA concentrations were revealed in Bergmann glia cells. Because the temproal expression profile of Mlc1 indicates that, in contrast to developing and mature astrocytes, oligodendrocytes are devoid of Mlc1 expression, white matter tract abnormalities observed in these disorders may result from a primary astrocytic defect. Detailed information on Mlc1 expression in brain is likely to lead to a better understanding of Mlc1 involvement in the pathogenesis of both MLC and catatonic schizophrenia. © 2003 Wiley‐Liss, Inc.
Heat transfer mechanism of a swirling impinging jet in a stagnation region
Authors: Nozaki Atsushi , Igarashi Yasumitsu , Hishida Koichi
Published: November 2003

Heat transfer characteristics of a swirling impinging jet have been experimentally examined using a combined particle image velocimetry (PIV) and laser‐induced fluorescence (LIF) technique for simultaneous measurement of velocity and temperature fields. The present study shows that the radial width of the jet stretches with increasing swirl intensity, and that the stretching phenomenon contributes to the maximum local heat transfer coefficient. At the stagnation region, the flow near the heated surface is mixed intermittently by reverse flows toward upstream, and spatial distributions of temperature are correlated with instantaneous velocity vector maps. The dynamic behavior of recirculation zones, attributed to swirl number Sw and impinging distance, mainly determines the turbulent heat transfer at the stagnation region. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 663–673, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10120
Combined nongray radiative and conductive heat transfer in multiple glazing taking into account specular reflection and absorption
Authors: Maruyama Shigenao , Mori Yusuke , Chikira Chie , Sakai Seigo
Published: November 2003

The problem of combined nongray radiative and conductive heat transfer in multiple glazing subjected to solar irradiation is analyzed. A spectral solar model proposed by Bird and Riordan is used to calculate direct and diffuse solar irradiance. The radiation element method by ray emission model, REM2, is used to analyze the spectral dependence of radiative heat transfer. Specular reflection at boundary surfaces is taken into account. The spectral dependence of radiation properties of glass such as specular reflectivity, refraction angle, and absorption coefficient is taken into account. The steady‐state temperature and heat flux distributions in the glass layer are obtained and the insulating efficiency of multiple glazing is examined. The overall heat transfer coefficients predicted by the present method are compared with those based on the JIS method. The values obtained by the present method are slightly lower than those obtained by the JIS method. To investigate the spectral variation of radiative heat flux attenuated in the glass layer, the spectral heat flux at the room‐side surface and incident radiation are compared. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 712–726, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10125
Human intestinal epithelial crypt cell survival and death: Complex modulations of Bcl‐2 homologs by Fak, PI3‐K/Akt‐1, MEK/Erk, and p38 signaling pathways
Authors: Harnois Charlène , Demers Marie‐Josée , Bouchard Véronique , Vallée Karine , Gagné David , Fujita Naoya , Tsuruo Takashi , Vézina Anne , Beaulieu Jean‐François , Côté André , Vachon Pierre H.
Published: November 2003

To investigate the mechanisms responsible for survival and apoptosis/anoikis in normal human intestinal epithelial crypt cells, we analyzed the roles of various signaling pathways and cell adhesion on the expression of six Bcl‐2 homologs (Bcl‐2, Bcl‐XL, Mcl‐1, Bax, Bak, Bad) in the well established HIEC‐6 cell model. Pharmacological inhibitors and/or dominant‐negative constructs were used to inhibit focal adhesion kinase (Fak) and p38 isoforms, as well as the phosphatidylinositol 3′‐kinase (PI3‐K)/Akt‐1 and mitogen‐activated protein kinase [MAPK] kinase (MEK)/extracellular regulated kinases (Erk) pathways. Cell adhesion was disrupted by antibody‐inhibition of integrin binding or forced cell suspension. The activation levels of studied kinase pathways were also analyzed. Herein, we report that β1 integrins, Fak, and the PI3‐K/Akt‐1 pathway, but not β4 integrins or the MEK/Erk pathway, are crucial for the survival of HIEC‐6 cells. Conversely, p38β, but not p38α or γ, is required for the induction of apoptosis/anoikis in HIEC‐6 cells. However, each of the signaling molecules/pathways analyzed were found to affect distinctively the individual expression of the Bcl‐2 homologs studied. For example, the inhibition of the PI3‐K/Akt‐1 pathway down‐regulated Bcl‐XL, Mcl‐1, and Bad, while at the same time up‐regulating Bax, whereas the inhibition of Fak up‐regulated both Bax and Bak, down‐regulated Bad, and did not affect the other Bcl‐2 homologs analyzed. These results indicate that integrins, Fak, PI3‐K/Akt‐1, MEK/Erk, and p38 isoforms perform distinct roles in the regulation of HIEC‐6 cell survival and/or death. In addition, our data show that the functions performed by these molecules/pathways in promoting cell survival or apoptosis/anoikis translate into complex, differential modulations of individual Bcl‐2 homologs. J. Cell. Physiol. 198: 209–222, 2004© 2003 Wiley‐Liss, Inc.
Early nuclear exclusion of the transcription factor max is associated with retinal ganglion cell death independent of caspase activity
Authors: Petrs‐Silva Hilda , de Freitas Fabíola G. , Linden Rafael , Chiarini Luciana B.
Published: November 2003

We examined the behavior of the transcription factor Max during retrograde neuronal degeneration of retinal ganglion cells. Using immunohistochemistry, we found a progressive redistribution of full‐length Max from the nucleus to the cytoplasm and dendrites of the ganglion cells following axon damage. Then, the axotomized cells lose all their content of Max, while undergoing nuclear pyknosis and apoptotic cell death. After treatment of retinal explants with either anisomycin or thapsigargin, the rate of nuclear exclusion of Max accompanied the rate of cell death as modulated by either drug. Treatment with a pan‐caspase inhibitor abolished both TUNEL staining and immunoreactivity for activated caspase‐3, but did not affect the subcellular redistribution of Max immunoreactivity after axotomy. The data show that nuclear exclusion of the transcription factor Max is an early event, which precedes and is independent of the activation of caspases, during apoptotic cell death in the central nervous system.
J. Cell. Physiol. 198: 179–187, 2004© 2003 Wiley‐Liss, Inc.
17β‐estradiol downregulates β3‐integrin expression in differentiating and mature human osteoclasts
Authors: Saintier D. , Burde M.‐A. , Rey J.M. , Maudelonde T. , de Vernejoul M.C. , Cohen‐Solal M.E.
Published: November 2003

The increased bone resorption observed after estrogen withdrawal is responsible for bone loss and may lead to osteoporosis. The mechanism by which estradiol inhibits bone resorption is known to involve decreased osteoclastogenesis, however, the effect on osteoclast adhesion remains unclear. We examined the in vitro effect of estradiol and raloxifene on human osteoclast differentiation and function. Human peripheral blood mononuclear cells were cultured with M‐CSF/RANK‐L for 18 days, and we evaluated bone resorption, the expression of the protein and mRNA of the integrins, c‐jun and c‐fos in the presence or absence of estradiol. In this human model, β3‐integrin expression increased at the mRNA and protein levels during osteoclast differentiation, whereas that of β5‐integrin did not. We found that estradiol and raloxifene directly inhibited bone resorption on bone slices by 50%, and decreased the expression of β3‐integrin mRNA (60%) and protein (20%) in a time‐dependent manner. Moreover, the mRNAs of c‐fos and c‐jun were both diminished by estradiol and raloxifene, particularly in early osteoclasts, but also to a lesser extent in mature cells. These findings suggest that the direct inhibitory action of estradiol on bone resorption may affect human osteoclast differentiation through downregulation of c‐fos and c‐jun and adhesion through modulation of β3‐integrin. J. Cell. Physiol. 198: 269–276, 2004© 2003 Wiley‐Liss, Inc.
Reduction of intracellular pH inhibits constitutive expression of Cyclooxygenase‐2 in human colon cancer cells
Authors: Pirkebner Daniela , Fuetsch Michaela , Wittmann Walter , Weiss Helmut , Haller Thomas , Schramek Herbert , Margreiter Raimund , Amberger Albert
Published: November 2003

Cyclooxygenase‐2 (COX‐2) over‐expression is critically involved in tumor formation. Intracellular pH (pHi) has been shown to be alkaline in cancer cells, and to be an important trigger for cell proliferation. This study therefore analyzed the relationship between pHi and COX‐2 expression. HRT‐18 and Caco‐2 cells cultured in medium with bicarbonate maintained a pHi of ∼7.6, which is higher than that of non‐neoplastic cells. Cells grown in bicarbonate‐free medium with a pH at 6.8 showed a reduction in pHi to approximately 7.0. Importantly, reduction of pHi resulted in a complete inhibition of COX‐2 mRNA and protein expression. When cells were grown in bicarbonate‐supplemented medium at pH 6.8, pHi maintained at ∼7.6 and COX‐2 expression was not inhibited. Additionally, analysis utilizing protein synthesis inhibitor cycloheximide demonstrated that pHi mediated inhibition of COX‐2 mRNA expression requires de novo protein synthesis of regulatory protein(s). These data strongly suggest that an alkaline pHi is an important trigger for constitutive COX‐2 expression. Defining pHi‐mediated mechanisms that govern the constitutive COX‐2 expression may help in developing new strategies to block COX‐2 over‐expression in cancer cells. J. Cell. Physiol. 198: 295–301, 2004© 2003 Wiley‐Liss, Inc.
Modulation of vascular smooth muscle cells proteoglycan synthesis by the extracellular matrix
Authors: Figueroa Julio E. , Oubre John , Vijayagopal Parakat
Published: November 2003

In this study, we investigated the effect of the extracellular matrix (ECM) secreted by vascular cells on proteoglycan (PG) synthesis by vascular smooth muscle cells in culture. PG synthesis of human aortic smooth muscle cells plated on plastic or the matrices derived from vascular endothelial cells, vascular smooth muscle cells, or THP‐1 macrophages was characterized. Smooth muscle cell and macrophage matrices increased both secreted and cellular smooth muscle cells PG production by 2.5‐fold to 3.9‐fold, respectively, over plastic and endothelial cell matrix. Macrophage matrix was more potent than smooth muscle cell matrix in this regard. Selective enzymatic removal of chondroitin sulfates, collagen, and elastin from smooth muscle cell matrix enhanced the stimulation of PG synthesis, as did the removal of chondroitin sulfates from macrophage matrix. PG turnover rates were similar for smooth muscle cells plated on the three matrices. The newly synthesized PG from cultures plated on smooth muscle cell‐, and macrophage‐derived matrices had greater charge density, larger molecular size, and longer glycosaminoglycan chains than those from endothelial cell matrix cultures. These data show that the ECM plays a major role in modulating vascular smooth muscle cell PG metabolism in vitro. J. Cell. Physiol. 198: 302–309, 2004© 2003 Wiley‐Liss, Inc.
Dermatan sulfate exerts an enhanced growth factor response on skeletal muscle satellite cell proliferation and migration
Authors: Villena Joan , Brandan Enrique
Published: November 2003

Skeletal muscle regeneration is a complex process in which many agents are involved. When skeletal muscle suffers an injury, quiescent resident myoblasts called satellite cells are activated to proliferate, migrate, and finally differentiate. This whole process occurs in the presence of growth factors, the extracellular matrix (ECM), and infiltrating macrophages. We have shown previously that different proteoglycans, either present at the plasma membrane or the ECM, are involved in the differentiation process by regulating growth factor activity. In this article, we evaluated the role of glycosaminoglycans (GAGs) in myoblast proliferation and migration, using C2C12, a satellite cell‐derived cell line. A synergic stimulatory effect on myoblast proliferation was observed with hepatocyte growth factor (HGF) and fibroblast growth factor type 2 (FGF‐2), which was dependent on cell sulfation. The GAG dermatan sulfate (DS) enhanced HGF/FGF‐2‐dependent proliferation at 1–10 ng/ml. However, decorin, a proteoglycan containing DS, was unable to reproduce this enhanced proliferative effect. On the other hand, HGF strongly increased myoblast migration. The HGF‐dependent migratory process required the presence of sulfated proteoglycans/GAGs present on the myoblast surface, as inhibition of both cell sulfation, and heparitinase (Hase) and chondroitinase ABC (Chabc) treatment of myoblasts, resulted in a very strong inhibition of cell migration. Among the GAGs analyzed, DS most increased HGF‐dependent myoblast migration. Taken together, these findings showed that DS is an enhancer of growth factor‐dependent proliferation and migration, two critical processes involved in skeletal muscle formation. J. Cell. Physiol. 198: 169–178, 2004© 2003 Wiley‐Liss, Inc.
Aldehydes mediate tissue factor induction: A possible mechanism linking lipid peroxidation to thrombotic events
Authors: Cabré Anna , Girona Josefa , Vallvé Joan‐C. , Masana Lluís
Published: November 2003

Tissue factor (TF), which is expressed in atherosclerotic plaques and colocalizes with oxidized lipids, initiates the thrombogenic process. We have analyzed the effect of aldehydes derived from peroxidation of polyunsaturated fatty acids on TF expression in human vascular smooth muscle cells (HVSMC). Our results demonstrate that hexanal and 2,4‐decadienal (2,4‐DDE), two apolar aldehydes, increase TF expression. Exposure of HVSMC to hexanal for 2 h led to TF protein levels up to seven times higher than untreated cells whereas 2,4‐DDE for 30 min led to them being up to 2.2 times higher. This induction of TF antigen by aldehydes correlates with an increase in TF mRNA levels. Electrophoretic mobility shift assays (EMSAs) showed that the binding activity of the transcription factor AP‐1 (c‐Fos/c‐Jun) to TF promoter was elevated in response to these oxidation products. This enhancement was associated to an increase of c‐fos transcriptional activity, which was reversible by pretreatment with simvastatin. We conclude that the induction of TF by aldehydes might contribute to the severity of atherogenesis.
J. Cell. Physiol. 198: 230–236, 2004© 2003 Wiley‐Liss, Inc.
PDTC, metal chelating compound, induces G1 phase cell cycle arrest in vascular smooth muscle cells through inducing p21Cip1 expression: Involvement of p38 mitogen activated protein kinase
Authors: Moon Sung‐Kwon , Jung Sun‐Young , Choi Yung‐Hyun , Lee Young‐Choon , Patterson Cam , Kim Cheorl‐Ho
Published: November 2003

Pyrrolidine dithiocarbamate (PDTC), a metal chelating compound, is known to induce cell death in vascular smooth muscle cells (VSMC). However, the molecular mechanism for PDTC‐induced VSMC death is not well understood. Addition of PDTC reduced cell growth and DNA synthesis on VSMC in low density conditions. However, in serum depleted medium, PDTC did not affect the cell viability, suggesting that certain factors in serum may mediate the cytotoxic effect of PDTC. Several metal chelators prevented the cell death induced by PDTC. In a serum‐deprived condition, addition of exogenous metals, copper, iron, and zinc, restored the cytotoxic effect of PDTC. These data indicate that metals such as copper, iron, and zinc in serum may mediate the cytotoxic effect of PDTC. At low VSMC density in 10% FBS, treatment of PDTC, which induced a cell‐cycle block in G1‐phase, induced down‐regulation of cyclins and CDKs and up‐regulation of the CDK inhibitor p21 expression, whereas up‐regulation of p27 or p53 by PDTC was not observed. Finally, we determined PDTC‐mediated signaling pathway involved in VSMC death. Among relevant pathways, PDTC induced marked activation of p38MAPK and JNK. Expression of dominant negative p38MAPK and SB203580, a p38MAPK specific inhibitor, blocked PDTC‐dependent p38MAPK, growth inhibition, and p21 expression. These data demonstrate that the p38MAPK pathway participates in p21 induction, which consequently leads to decrease of cyclin D1/cdk4 and cyclin E/cdk2 complexes and PDTC‐dependent VSMC growth inhibition. In conclusion, an understanding of the molecular mechanisms of PDTC in VSMC provides a theoretical basis for clinical approaches using antioxidant therapies in atherosclerosis. J. Cell. Physiol. 198: 310–323, 2004© 2003 Wiley‐Liss, Inc.
Raman study of magnetite (Fe3O4): laser‐induced thermal effects and oxidation
Authors: Shebanova Olga N. , Lazor Peter
Published: November 2003

Natural magnetite (Fe3O4) in the form of single crystal and powder was studied by laser Raman spectroscopy at various laser powers. The correlations between the power of the excitation laser, the temperature of the sampled spot and the degree of oxidation of magnetite were accurately established. In the course of the oxidation of the single crystal of magnetite, the first characteristic features of hematite appear at about 300 and 410 cm−1, at a temperature close to 240°C. This may explain the erroneous assignment of these modes to the intrinsic Raman modes of magnetite in some studies. For the finely powdered magnetite, which is much more easily prone to oxidation, the reaction mechanism proceeds via a metastable maghemite (γ‐Fe2O3) before the final product hematite is formed. Three independent methods based on the quasi‐harmonic approximation and on the ratio of the Stokes to anti‐Stokes intensities were used to calculate the local temperature of the laser‐heated spot. Temperature‐induced shifts of phonon bands were also evaluated. The phonons shift at the following rates: A1g − 0.023(1) cm−1 K−1, T2g(2) − 0.030(2) cm−1 K−1, Eg − 0.019(5) cm−1 K−1 and T2g(1) − 0.00(1) cm−1 K−1. Copyright © 2003 John Wiley & Sons, Ltd.
Density functional andab initiostudies of the molecular structure and vibrational spectra of novelO,O′‐diethyl‐N‐(α‐aryloxyacetyl)thiophosphorylhydrazine herbicides
Authors: Li Wei , Wu Qiaofeng , Ye Yong , Luo Mingdao , Shi Deqing , Hu Jiming
Published: November 2003

The ground‐state geometry, vibrational wavenumbers and thermodynamic parameters ofO,O′‐diethyl‐N‐(α‐acetonaphthalene)thiophosphorylhydrazine andO,O′‐diethyl‐N‐(α‐2‐methylphenoxyacetyl)thiophosphorylhydrazine were studied by DFT‐B3LYP, B3PW91 andab initioRHF methods. The optimized geometries and some thermodynamic parameters obtained by using different methods and basis sets were compared. The wavenumber of the stretching vibration of the CO group ofO,O′‐diethyl‐N‐(α‐acetonaphthalene)thiophosphorylhydrazine is shifted down significantly because of intra or intermolecular hydrogen bonds formed among the molecules. Copyright © 2003 John Wiley & Sons, Ltd.
Structural characterization of self‐assembled monolayers by unenhanced Raman spectroscopy
Authors: Choplin F. , Navarre S. , Bousbaa J. , Babin P. , Bennetau B. , Bruneel J.‐L. , Desbat B.
Published: November 2003

This paper presents unenhanced Raman spectra of self‐assembled monolayers [2‐(22‐trichlorosilanyldocosoxy)ethyl acetate], grafted on to silicon dioxide wafers, obtained by using a confocal Raman microscope. The quality of monolayer formation, at the micrometer scale, was monitored by drawing maps of a few square micrometers and homogeneous monolayers were obtained using a detergent cleaning procedure. The results are in good agreement with those obtained previously by atomic force microscopy studies. Copyright © 2003 John Wiley & Sons, Ltd.
Collaborative data processing in developing predictive models of complex reaction systems
Authors: Frenklach Michael , Packard Andrew , Seiler Pete , Feeley Ryan
Published: November 2003

The subject of this report is a methodology for the transformation of (experimental) data into predictive models. We use a concrete example, drawn from the field of combustion chemistry, and examine the data in terms of precisely defined modes of scientific collaboration. The numerical methodology that we employ is founded on a combination of response surface technique and robust control theory. The numerical results show that an essential element of scientific collaboration is collaborative processing of data, demonstrating that combining the entire collection of data into a joint analysis extracts substantially more of the information content of the data. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 57–66, 2004
Itinerant ferromagnetism and antiferromagnetism from the perspective of chemical bonding
Authors: Dronskowski Richard
Published: November 2003

The quantum chemical tool crystal orbital Hamilton population (COHP) has been used for the analysis of bonding within metallic systems to predict the tendency for ferromagnetic and antiferromagnetic order. In these materials, the preference of bonding interactions and avoidance of antibonding interactions is realized not by conventional Jahn–Teller/Peierls distortions but simply by rearranging the spin sublattices upon spontaneous spin polarization. In general, spin‐restricted bonding analyses of itinerant metals with a tendency for ferromagnetic order (such as α‐Fe, Co, and Ni) exhibitantibondingstates at the Fermi level that disappear upon going ferromagnetic; within the elemental metals the onset of magnetism strengthens the metalmetal bond. A typical antiferromagnet (Cr) showsnonbondingstates in the highest bands that remain almost untouched during spin polarization. This bonding classification of potential ferro‐ or antiferromagnets also holds for intermetallic alloys and can be utilized for rational syntheses. The recipe is exemplified with the help of multinary iron/manganese rhodium borides in which various adjustments of the Fermi level have been synthetically realized. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Quantum chemical calculation of crystalline model of biomembrane
Authors: Evarestov R. A. , Stefanov V. E. , Karasev V. A. , Bandura A. V.
Published: November 2003

A theoretical study on the possibility of protons transfer in biomembranes via continuous systems of hydrogen bonds was carried out on the basis of a simple crystalline model IPE–HCl (crystals of phosphatidylethanolamine titrated with HCl). A combined approach was used involving optimization of atomic structure by the method of molecular mechanics and subsequent nonempirical quantum chemistry calculation of the electronic structure of IPE–HCl. For hydrogen atoms, molecular mechanics yielded more precise positions compared to those found in the experimental X‐ray study (monoclinic space group C2/c, 240 atoms in primitive unit cell). Quantum chemistry calculation of the electronic structure of IPE–HCL crystal was performed on the basis of the optimized atomic positions. The nonempirical Hartree–Fock LCAO method is used as in computer code CRYSTAL. The calculated values of Mulliken charges on hydrogen atoms in P‐O‐H groups are essentially closer to those for protons than are the values of charge on other hydrogen atoms. This result supports the assumption about the importance of systems of hydrogen bonds in the membrane‐like structures. In agreement with the proton mechanism of energy transfer, presumed for biomembranes, total energy of the atomic configuration with transferred proton is close to that of undistorted structure. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Investigation of interatomic bonding in 3C‐SiC:M by nonempirical quantum chemistry methods
Authors: Yuryeva E. I. , Ivanovskii A. L.
Published: November 2003

In this work, the presence of 3d metal (MTi, V, Cr and Ni) impurity atoms in the cubic silicon carbide (3C‐SiC) was simulated theoretically. Electronic structure, parameters of chemical bonding, and binding energies were calculated by the cluster density functional theory DFT approach for M substitutions in silicon, carbon, and interstitial sites. The full‐potential FLMTO technique was employed to calculate the cohesive energy for the M → Si substitutions and the crystal lattice relaxation effects around the impurity atoms. We found that for stoichiometric substitutions all 3d impurities occupy Si positions but for nonstoichiometric SiC the Ti, V(Ni), and Cr atoms may also occupy the interstitial, Si, and C sites, respectively. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Transaction cost‐enhanced entry mode choices and firm performance
Authors: Brouthers Keith D. , Brouthers Lance Eliot , Werner Steve
Published: November 2003

According to transaction cost theory, firms select the international mode of entry that provides the most efficient form of governance. However, previous scholarship largely neglects the impact of transaction cost variables on entry mode choice and firm performance. In this study, we add transaction cost variables to a set of variables previously used to predict firm mode choice and performance. We theorize and find that firms selecting these ‘transaction cost‐enhanced international entry modes’ perform better than firms using other modes of entry. Based on our results, we conclude that ‘enhanced’ transaction cost theory appears to be normative as well as descriptive with respect to international entry mode decisions. Copyright © 2003 John Wiley & Sons, Ltd.