bluuebunny/crossref_metadata_2025 huggingface dataset:
Discrimination of complex synthetic echoes by an echolocating bottlenose dolphin
Authors: Helweg David A. , Moore Patrick W. , Dankiewicz Lois A. , Zafran Justine M. , Brill Randall L.
Published: January 2003

Bottlenose dolphins (Tursiops truncatus) detect and discriminate underwater objects by interrogating the environment with their native echolocation capabilities. Study of dolphins’ ability to detect complex (multihighlight) signals in noise suggest echolocation object detection using an approximate 265-μs energy integration time window sensitive to the echo region of highest energy or containing the highlight with highest energy. Backscatter from many real objects contains multiple highlights, distributed over multiple integration windows and with varying amplitude relationships. This study used synthetic echoes with complex highlight structures to test whether high-amplitude initial highlights would interfere with discrimination of low-amplitude trailing highlights. A dolphin was trained to discriminate two-highlight synthetic echoes using differences in the center frequencies of the second highlights. The energy ratio (ΔdB) and the timing relationship (ΔT) between the first and second highlights were manipulated. An iso-sensitivity function was derived using a factorial design testing ΔdB at −10, −15, −20, and −25 dB and ΔT at 10, 20, 40, and 80 μs. The results suggest that the animal processed multiple echo highlights as separable analyzable features in the discrimination task, perhaps perceived through differences in spectral rippling across the duration of the echoes.
Modulation rate discrimination for unresolved components: Temporal cues related to fine structure and envelope
Authors: Hall Joseph W. , Buss Emily , Grose John H.
Published: January 2003

The present study investigated the hypothesis that the cues for modulation rate discrimination for unresolved spectral components differ as a function of the spectral region occupied by the stimuli. Specifically, it was hypothesized that when components occupy relatively low spectral regions, phase locking both to the fine structure and to the envelope are useful cues. However, as the spectral region occupied by the components increases, phase locking to the fine structure becomes less robust, whereas phase locking to the envelope remains as a potentially strong cue. Observers were asked to detect a decrease in modulation rate for carrier frequencies between 1500 and 6000 Hz. Both amplitude-modulated (AM) and quasifrequency-modulated (QFM) tones were used in order to produce stimuli having strong and weak envelope cues, respectively. Although there were marked individual differences, the results showed an interaction between modulation type and spectral region, with AM and QFM performance being relatively similar at low spectral region, but with QFM showing a steeper reduction in performance as the spectral region of the carrier frequency increased. Overall, the data are consistent with an interpretation that pitch perception for unresolved components depends upon both fine structure and envelope cues, and that the relative importance of these cues depends upon the spectral region occupied by the stimuli.
A mechanical model of vocal-fold collision with high spatial and temporal resolution
Authors: Gunter Heather E.
Published: January 2003

The tissue mechanics governing vocal-fold closure and collision during phonation are modeled in order to evaluate the role of elastic forces in glottal closure and in the development of stresses that may be a risk factor for pathology development. The model is a nonlinear dynamic contact problem that incorporates a three-dimensional, linear elastic, finite-element representation of a single vocal fold, a rigid midline surface, and quasistatic air pressure boundary conditions. Qualitative behavior of the model agrees with observations of glottal closure during normal voice production. The predicted relationship between subglottal pressure and peak collision force agrees with published experimental measurements. Accurate predictions of tissue dynamics during collision suggest that elastic forces play an important role during glottal closure and are an important determinant of aerodynamic variables that are associated with voice quality. Model predictions of contact force between the vocal folds are directly proportional to compressive stress (r2=0.79), vertical shear stress (r2=0.69), and Von Mises stress (r2=0.83) in the tissue. These results guide the interpretation of experimental measurements by relating them to a quantity that is important in tissue damage.
Time-domain simulation of sound production of the sho
Authors: Hikichi Takafumi , Osaka Naotoshi , Itakura Fumitada
Published: January 2003

A physical model based on the sound production mechanism of the sho is proposed with intention of applying it to sound synthesis. Time-domain simulation was done using this model, and effects of the tube length and blowing pressure on the sounding frequency and sounds spectra were investigated. The reed vibration, pressure variation inside the tube, and threshold blowing pressure for oscillation were measured by artificially blowing air into the sho. The experimental results are in acceptable agreement with simulation results in terms of the relationships between tube length and threshold pressure and between tube length and the sounding frequency. In addition, recorded sound waveforms and simulated ones have a common feature in the sense that high-frequency components of their spectra increase with increasing blowing pressure. Further, it is concluded that a sho reed acts as an “outward-striking valve.”
Active control of acoustic reflection, absorption, and transmission using thin panel speakers
Authors: Zhu H. , Rajamani R. , Stelson K. A.
Published: January 2003

This paper explores the development of thin panels that can be controlled electronically so as to provide surfaces with desired reflection coefficients. Such panels can be used as either perfect reflectors or absorbers. They can also be designed to be transmission blockers that block the propagation of sound. The development of the control system is based on the use of wave separation algorithms that separate incident sound from reflected sound. In order to obtain a desired reflection coefficient, the reflected sound is controlled to appropriate levels. The incident sound is used as an acoustic reference for feedforward control and has the important property of being isolated from the action of the control system speaker. In order to use a panel as a transmission blocker, the acoustic pressure behind the panel is driven to zero. The use of the incident signal as a reference again plays a key role in successfully reducing broadband transmission of sound. The panels themselves are constructed using poster board and small rare-earth actuators. Detailed experimental results are presented showing the efficacy of the algorithms in achieving real-time control of reflection or transmission. The panels are able to effectively block transmission of broadband sound. Practical applications for these panels include enclosures for noisy machinery, noise-absorbing wallpaper, the development of sound walls, and the development of noise-blocking glass windows.
A mixed finite element method for acoustic wave propagation in moving fluids based on an Eulerian–Lagrangian description
Authors: Treyssède Fabien , Gabard Gwénaël , Ben Tahar Mabrouk
Published: January 2003

A nonstandard wave equation, established by Galbrun in 1931, is used to study sound propagation in nonuniform flows. Galbrun’s equation describes exactly the same physical phenomenon as the linearized Euler’s equations (LEE) but is derived from an Eulerian–Lagrangian description and written only in term of the Lagrangian perturbation of the displacement. This equation has interesting properties and may be a good alternative to the LEE: only acoustic displacement is involved (even in nonhomentropic cases), it provides exact expressions of acoustic intensity and energy, and boundary conditions are easily expressed because acoustic displacement whose normal component is continuous appears explicitly. In this paper, Galbrun’s equation is solved using a finite element method in the axisymmetric case. With standard finite elements, the direct displacement-based variational formulation gives some corrupted results. Instead, a mixed finite element satisfying the inf-sup condition is proposed to avoid this problem. A first set of results is compared with semianalytical solutions for a straight duct containing a sheared flow (obtained from Pridmore–Brown’s equation). A second set of results concerns a more complex duct geometry with a potential flow and is compared to results obtained from a multiple-scale method (which is an adaptation for the incompressible case of Rienstra’s recent work).
Development of form and function in peripheral auditory structures of the zebrafish (Danio rerio)
Authors: Higgs Dennis M. , Rollo Audrey K. , Souza Marcy J. , Popper Arthur N.
Published: January 2003

Investigations of the development of auditory form and function have, with a few exceptions, thus far been largely restricted to birds and mammals, making it difficult to postulate evolutionary hypotheses. Teleost fishes represent useful models for developmental investigations of the auditory system due to their often extensive period of posthatching development and the diversity of auditory specializations in this group. Using the auditory brainstem response and morphological techniques we investigated the development of auditory form and function in zebrafish (Danio rerio) ranging in size from 10 to 45 mm total length. We found no difference in auditory sensitivity, response latency, or response amplitude with development, but we did find an expansion of maximum detectable frequency from 200 Hz at 10 mm to 4000 Hz at 45 mm TL. The expansion of frequency range coincided with the development of Weberian ossicles in zebrafish, suggesting that changes in hearing ability in this species are driven more by development of auxiliary specializations than by the ear itself. We propose a model for the development of zebrafish hearing wherein the Weberian ossicles gradually increase the range of frequencies available to the inner ear, much as middle ear development increases frequency range in mammals.
Patterns of phoneme perception errors by listeners with cochlear implants as a function of overall speech perception ability
Authors: Munson Benjamin , Donaldson Gail S. , Allen Shanna L. , Collison Elizabeth A. , Nelson David A.
Published: January 2003

Many studies have noted great variability in speech perception ability among postlingually deafened adults with cochlear implants. This study examined phoneme misperceptions for 30 cochlear implant listeners using either the Nucleus-22 or Clarion version 1.2 device to examine whether listeners with better overall speech perception differed qualitatively from poorer listeners in their perception of vowel and consonant features. In the first analysis, simple regressions were used to predict the mean percent-correct scores for consonants and vowels for the better group of listeners from those of the poorer group. A strong relationship between the two groups was found for consonant identification, and a weak, nonsignificant relationship was found for vowel identification. In the second analysis, it was found that less information was transmitted for consonant and vowel features to the poorer listeners than to the better listeners; however, the pattern of information transmission was similar across groups. Taken together, results suggest that the performance difference between the two groups is primarily quantitative. The results underscore the importance of examining individuals’ perception of individual phoneme features when attempting to relate speech perception to other predictor variables.
Numerical homogenization techniques applied to piezoelectric composites
Authors: Lenglet Eve , Hladky-Hennion Anne-Christine , Debus Jean-Claude
Published: January 2003

With the recent availability of piezoelectric fibers, the design and the analysis of piezoelectric composites needs new modeling tools. Therefore, a numerical homogenization technique has been developed, based on the ATILA finite element code, that combines two techniques: one relying upon the representative volume element (RVE) the other relying upon the wave propagation (WP). The combination of the two methods allows the whole tensor of the homogenized properties of the piezoelectric composite to be found. Considering a fiber embedded in epoxy, the numerical results are compared to the results obtained using previous analytical models, thus validating the models. Even if the method is presented in a particular case, its extension to any piezoelectric composite is straightforward.
The effect of a low-frequency sound source (acoustic thermometry of the ocean climate) on the diving behavior of juvenile northern elephant seals, Mirounga angustirostris
Authors: Costa Daniel P. , Crocker Daniel E. , Gedamke Jason , Webb Paul M. , Houser Dorian S. , Blackwell Susanna B. , Waples Danielle , Hayes Sean A. , Le Boeuf Burney J.
Published: January 2003

Changes in the diving behavior of individual free-ranging juvenile northern elephant seals, Mirounga angustirostris, exposed to the acoustic thermometry of the ocean climate (ATOC) sound source were examined using data loggers. Data loggers were attached to the animals and measured swim speed, maximum depth of dive, dive duration, surface interval, descent and ascent rate, and descent and ascent angle along with sound pressure level (SPL). The ATOC sound source was at a depth of 939 m and transmitted at 195 dB re: 1 μPa at 1 m centered at 75 Hz with a 37.5-Hz bandwidth. Sound pressure levels (SPL) measured at the seal during transmissions averaged 128 dB and ranged from 118 to 137 dB re: 1 μPa for the 60–90 Hz band, in comparison to ambient levels of 87–107 dB within this band. In no case did an animal end its dive or show any other obvious change in behavior upon exposure to the ATOC sound. Subtle changes in diving behavior were detected, however. During exposure, deviations in descent rate were greater than 1 s.d. of the control mean in 9 of 14 seals. Dive depth increased and descent velocity increased in three animals, ascent velocity decreased in two animals, ascent rate increased in one animal and decreased in another, and dive duration decreased in only one animal. There was a highly significant positive correlation between SPL and descent rate. The biological significance of these subtle changes is likely to be minimal. This is the first study to quantify behavioral responses of an animal underwater with simultaneous measurements of SPL of anthropogenic sounds recorded at the animal.
Suppressing Roughness of Virtual Times in Parallel Discrete-Event Simulations
Authors: Korniss G. , Novotny M. A. , Guclu H. , Toroczkai Z. , Rikvold P. A.
Published: January 2003

In a parallel discrete-event simulation (PDES) scheme, tasks are distributed among processing elements (PEs) whose progress is controlled by a synchronization scheme. For lattice systems with short-range interactions, the progress of the conservative PDES scheme is governed by the Kardar-Parisi-Zhang equation from the theory of nonequilibrium surface growth. Although the simulated (virtual) times of the PEs progress at a nonzero rate, their standard deviation (spread) diverges with the number of PEs, hindering efficient data collection. We show that weak random interactions among the PEs can make this spread nondivergent. The PEs then progress at a nonzero, near-uniform rate without requiring global synchronizations.
Architecture of Succinate Dehydrogenase and Reactive Oxygen Species Generation
Authors: Yankovskaya Victoria , Horsefield Rob , Törnroth Susanna , Luna-Chavez César , Miyoshi Hideto , Léger Christophe , Byrne Bernadette , Cecchini Gary , Iwata So
Published: January 2003

The structure of
Escherichia coli
succinate dehydrogenase (SQR), analogous to the mitochondrial respiratory complex II, has been determined, revealing the electron transport pathway from the electron donor, succinate, to the terminal electron acceptor, ubiquinone. It was found that the SQR redox centers are arranged in a manner that aids the prevention of reactive oxygen species (ROS) formation at the flavin adenine dinucleotide. This is likely to be the main reason SQR is expressed during aerobic respiration rather than the related enzyme fumarate reductase, which produces high levels of ROS. Furthermore, symptoms of genetic disorders associated with mitochondrial SQR mutations may be a result of ROS formation resulting from impaired electron transport in the enzyme.
Functional expression of the eotaxin receptor CCR3 in CD30+ cutaneous T-cell lymphoma
Authors: Kleinhans Martin , Tun-Kyi Adrian , Gilliet Michel , Kadin Marshall E. , Dummer Reinhard , Burg Günter , Nestle Frank O.
Published: January 2003

Little is known about mechanisms involved in skin-specific homing of cutaneous T-cell lymphoma (CTCL). Chemokine/chemokine receptor interactions have been implicated in the homing of lymphoma cells to various tissue sites. We investigated tissue samples and tumor cell suspensions of patients with CD30+ CTCL (n = 8) and CD30− CTCL (mycosis fungoides, n = 6; Sézary syndrome, n = 6) for expression of the chemokine receptors CCR3, CCR4, and CCR8 and the CCR3 ligands eotaxin/CCL11, monocyte chemoattractant protein 3 (MCP-3)/CCL7, and RANTES (regulated on activation, normal T expressed and secreted)/CCL5. Of 8 CD30+ CTCLs, 7 expressed CCR3, 4 CCR4, and none CCR8. CCR3 expression was not found in skin tissue samples from 12 CD30− CTCLs. Coexpression of CCR3 and CD30 was demonstrated by flow cytometry in tumor cell suspensions. Internalization experiments demonstrated functionality of CCR3 expressed by freshly isolated tumor cells. Actin polymerization as well as migration in response to eotaxin was demonstrated in a CD30+ cutaneous lymphoma cell line. CCR3 ligand eotaxin/CCL11 was detected in lesional skin of CD30+CTCL by immunohistochemistry, preferentially in tumor cells. Eotaxin/CCL11 expression in tumor cells was confirmed by intracellular immunofluorescence. Analysis of cytokine expression pattern of CCR3-bearing infiltrating cells showed a predominance of interleukin-4 (IL-4) but not interferon-γ (IFN-γ) protein expression,1 consistent with a T-helper 2 (Th-2) profile. These results suggest that expression of CCR3 and its ligand eotaxin/CCL11 plays a role in the recruitment and retention of CD30+ malignant T cells to the skin.
Immunolocalization of P2Y1 and TPα receptors in platelets showed a major pool associated with the membranes of α-granules and the open canalicular system
Authors: Nurden Paquita , Poujol Christel , Winckler Joelle , Combrié Robert , Pousseau Nathalie , Conley Pamela B. , Levy-Toledano Sylviane , Habib Aida , Nurden Alan T.
Published: January 2003

P2Y1 and thromboxane-prostanoid–α (TPα) receptors on platelets belong to the G-protein–coupled 7–transmembrane domain family. They transmit signals for shape change, mobilization of calcium, and platelet aggregation. Immunogold labeling with a monoclonal antibody (MoAb) to the amino-terminal domain of P2Y1 and a polyclonal antibody to the C-terminal domain of TPα revealed that while present at the platelet surface, both receptors were abundantly represented inside the platelet. Specifically, receptors were found in membranes of α-granules and elements of the open-canalicular system. A similar organization was found in mature megakaryocytes. Activation of platelets by adenosine diphosphate (ADP) and the thromboxane A2(TXA2) analog, I-BOP [1S-(1 α,2 β(5Z),3 α-(1E,3S)4 α)-7-(3-(3- hydroxy-4-(p-iodophenoxy)-1-butenyl)-7-oxabicyclo(2.2.1)hept-2-yl)-5-heptenoic acid], increased the labeling of both P2Y1 and TPα at the surface and in intracellular pools, suggesting that activation resulted in greater antibody accessibility to the receptor. A return to a platelet discoid shape and to basal values of labeling accompanied receptor desensitization. Platelets lacking the P2Y12 ADP receptor normally expressed P2Y1 and TPα, both before and after activation. Studies with the anti–ligand-induced binding site (anti-LIBS) MoAb, AP-6, confirmed that stored fibrinogen associated with internal pools of αIIbβ3 at the start of secretion in a microenvironment containing agonist receptors. Pharmacologic antagonism of ADP or TXA2 receptors in antithrombotic therapy may need to take into account blockade of internal receptor pools.
Loss of the B-lineage–specific gene expression program in Hodgkin and Reed-Sternberg cells of Hodgkin lymphoma
Authors: Schwering Ines , Bräuninger Andreas , Klein Ulf , Jungnickel Berit , Tinguely Marianne , Diehl Volker , Hansmann Martin-Leo , Dalla-Favera Riccardo , Rajewsky Klaus , Küppers Ralf
Published: January 2003

Hodgkin and Reed-Sternberg (HRS) cells represent the malignant cells in classical Hodgkin lymphoma (HL). Because their immunophenotype cannot be attributed to any normal cell of the hematopoietic lineage, the origin of HRS cells has been controversially discussed, but molecular studies established their derivation from germinal center B cells. In this study, gene expression profiles generated by serial analysis of gene expression (SAGE) and DNA chip microarrays from HL cell lines were compared with those of normal B-cell subsets, focusing here on the expression of B-lineage markers. This analysis revealed decreased mRNA levels for nearly all established B-lineage–specific genes. For 9 of these genes, lack of protein expression was histochemically confirmed. Down-regulation of genes affected multiple components of signaling pathways active in B cells, including B-cell receptor (BCR) signaling. Because several genes down-regulated in HRS cells are positively regulated by the transcriptional activator Pax-5, which is expressed in most HRS cells, we studied HL cell lines for mutations in the Pax-5gene. However, no mutations were found. We propose that the lost B-lineage identity in HRS cells may explain their survival without BCR expression and reflect a fundamental defect in maintaining the B-cell differentiation state in HRS cells, which is likely caused by a novel, yet unknown, pathogenic mechanism.
Differential CD52 expression by distinct myeloid dendritic cell subsets: implications for alemtuzumab activity at the level of antigen presentation in allogeneic graft-host interactions in transplantation
Authors: Ratzinger Gudrun , Reagan John L. , Heller Glenn , Busam Klaus J. , Young James W.
Published: January 2003

Alemtuzumab (anti-CD52; Campath 1-H) depletes both host and donor T cells when used in preparative regimens for allogeneic transplantation. This promotes engraftment even after nonmyeloablative conditioning and limits graft-versus-host disease (GVHD) even after unrelated or major histocompatibility complex (MHC) disparate allografts. We asked whether anti-CD52 differentially targets antigen-presenting cells (APCs), in addition to depleting T cells. Monocyte-derived dendritic cells (moDCs) expressed abundant CD52 as expected. Langerhans cells (LCs) and dermal-interstitial DCs (DDC-IDCs), however, never expressed CD52. Immunostaining of skin and gut confirmed the absence of CD52 on these resident DC populations under both steady-state and inflammatory conditions. Although anti-CD52 functions primarily by antibody-dependent cellular cytotoxicity (ADCC) in vivo, assessment of its activity in vitro included complement-dependent lysis of CD52+ cells. Anti-CD52 did not impair DC–T–cell adhesion, diminish DC-stimulated T-cell proliferation, or alter moDC development in vitro. We propose that anti-CD52 abrogates GVHD not only by T-cell depletion, but also by removing moDCs and their precursors. This would mitigate moDC phagocytosis and presentation of host-derived antigens to donor T cells in the inflammatory peritransplantation environment, thereby limiting GVHD. The sparing of LCs and DDC-IDCs by anti-CD52, as well as the recovery of donor-derived moDCs in a less inflammatory environment later after transplantation, may allow all these DCs to exert formative roles in graft-versus-tumor (GVT) reactions and immune reconstitution. Whether these results support a separation of deleterious from beneficial graft-host interactions at the level of antigen presentation, rather than solely at the level of T cells, will require further evaluation.
Low-dose total body irradiation (TBI) and fludarabine followed by hematopoietic cell transplantation (HCT) from HLA-matched or mismatched unrelated donors and postgrafting immunosuppression with cyclosporine and mycophenolate mofetil (MMF) can induce durable complete chimerism and sustained remissions in patients with hematological diseases
Authors: Niederwieser Dietger , Maris Michael , Shizuru Judith A. , Petersdorf Effie , Hegenbart Ute , Sandmaier Brenda M. , Maloney David G. , Storer Barry , Lange Thoralf , Chauncey Thomas , Deininger Michael , Pönisch Wolfram , Anasetti Claudio , Woolfrey Ann , Little Marie-Terese , Blume Karl G. , McSweeney Peter A. , Storb Rainer F.
Published: January 2003

Toxicities of high-dose conditioning regimens have limited the use of conventional unrelated donor hematopoietic cell transplantation (HCT) to younger, medically fit patients. Based on preclinical studies, an HCT approach has been developed for elderly or medically infirm patients with HLA-matched or mismatched unrelated donors. In this study, 52 patients with hematological diseases were included. Most (88%) had preceding unsuccessful conventional HCT or refractory/advanced disease. Patients were treated with fludarabine 30 mg/m2/d from days −4 to −2, 2 Gy total body irradiation on day 0, cyclosporine at 6.25 mg/kg twice daily from day −3, and mycophenolate mofetil at 15 mg/kg twice daily from day 0. Durable donor chimerism was attained in 88% of the patients. By day 28, a median of 100% of CD56+ cells were of donor origin. Granulocyte and T-cell donor chimerism increased to medians of 100% on day 56 and day 180 (range, 55%-100%), respectively. Acute GVHD, grade II, was seen in 42% (CI, 29%-56%); grade III in 8% (CI, 0%-15%); and grade IV in 13% (CI, 4%-23%) of patients; it was fatal in 9%. The 100-day transplantation-related mortality was 11%. Complete remissions, including molecular remissions, were seen in 45% of patients with measurable disease before transplantation. Mortality from disease progression was 27% at one year. With a median follow-up of 19 months, 18 of the 52 patients (35%) were alive and 25% were in remission. HCT from HLA-matched or mismatched unrelated donors can be performed with a reduced intensity conditioning regimen in patients ineligible for conventional HCT.
Fibrin fragment D-dimer and the risk of future venous thrombosis
Authors: Cushman Mary , Folsom Aaron R. , Wang Lu , Aleksic Nena , Rosamond Wayne D. , Tracy Russell P. , Heckbert Susan R.
Published: January 2003

Plasma D-dimer concentration rises more than 100-fold during acute deep vein thrombosis, but there are no prospective data concerning D-dimer as a risk factor for incident venous thrombosis in a general population. Incident venous thrombosis was ascertained in 2 prospective observational studies, the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study. Of 21 690 participants enrolled between 1987 and 1993, after 8 years of follow-up, D-dimer was measured using baseline stored plasma of 307 participants who developed venous thrombosis and 616 who did not. Relative to the first quintile of the distribution of D-dimer, the age-adjusted odds ratios for future venous thrombosis for the second to fifth quintiles of D-dimer were 1.6, 2.3, 2.3, and 4.2, respectively (P for trend < .0001). Following added adjustment for sex, race, body mass index, factor V Leiden, prothrombin 20210A, and elevated factor VIII coagulant activity (factor VIII:c), these odds ratios were 1.5, 2.1, 1.9, and 3.0, respectively (P for trend < .0001). Among those with idiopathic thrombosis or secondary thrombosis unrelated to cancer, the adjusted fifth quintile odds ratios were 3.5 and 4.8, respectively. By contrast, D-dimer in the fifth versus first quintile was not related to occurrence of cancer-associated thrombosis (odds ratio, 1.1). Odds ratios for elevated D-dimer were consistently elevated in subgroups defined by age, sex, race, duration of follow-up, and thrombosis type (deep vein thrombosis or pulmonary embolus). D-dimer is strongly and positively related to the occurrence of future venous thrombosis.
Protein kinase Cζ mediated Raf-1/extracellular-regulated kinase activation by daunorubicin
Authors: Mas Véronique Mansat-De , Hernandez Hélène , Plo Isabelle , Bezombes Christine , Maestre Nicolas , Quillet-Mary Anne , Filomenko Rodolphe , Demur Cécile , Jaffrézou Jean-Pierre , Laurent Guy
Published: January 2003

In light of the emerging concept of a protective function of the mitogen-activated protein kinase (MAPK) pathway under stress conditions, we investigated the influence of the anthracycline daunorubicin (DNR) on MAPK signaling and its possible contribution to DNR-induced cytotoxicity. We show that DNR increased phosphorylation of extracellular-regulated kinases (ERKs) and stimulated activities of both Raf-1 and extracellular-regulated kinase 1 (ERK1) within 10 to 30 minutes in U937 cells. ERK1 stimulation was completely blocked by either the mitogen-induced extracellular kinase (MEK) inhibitor PD98059 or the Raf-1 inhibitor 8-bromo-cAMP (cyclic adenosine monophosphate). However, only partial inhibition of Raf-1 and ERK1 stimulation was observed with the antioxidant N-acetylcysteine (N-Ac). Moreover, the xanthogenate compound D609 that inhibits DNR-induced phosphatidylcholine (PC) hydrolysis and subsequent diacylglycerol (DAG) production, as well as wortmannin that blocks phosphoinositide-3 kinase (PI3K) stimulation, only partially inhibited Raf-1 and ERK1 stimulation. We also observed that DNR stimulated protein kinase C ζ (PKCζ), an atypical PKC isoform, and that both D609 and wortmannin significantly inhibited DNR-triggered PKCζ activation. Finally, we found that the expression of PKCζ kinase-defective mutant resulted in the abrogation of DNR-induced ERK phosphorylation. Altogether, these results demonstrate that DNR activates the classical Raf-1/MEK/ERK pathway and that Raf-1 activation is mediated through complex signaling pathways that involve at least 2 contributors: PC-derived DAG and PI3K products that converge toward PKCζ. Moreover, we show that both Raf-1 and MEK inhibitors, as well as PKCζ inhibition, sensitized cells to DNR-induced cytotoxicity.
Rapamycin specifically interferes with GM-CSF signaling in human dendritic cells, leading to apoptosis via increased p27KIP1 expression
Authors: Woltman Andrea M. , van der Kooij Sandra W. , Coffer Paul J. , Offringa Rienk , Daha Mohamed R. , van Kooten Cees
Published: January 2003

The longevity of dendritic cells (DCs) is a critical regulatory factor influencing the outcome of immune responses. Recently, we demonstrated that the immunosuppressive drug rapamycin (Rapa) specifically induces apoptosis in DCs but not in other myeloid cell types. The present study unraveled the mechanism used by Rapa to induce apoptosis in human monocyte-derived DCs. Our data demonstrate that granulocyte-macrophage colony-stimulating factor (GM-CSF) preserves DC survival specifically via the phosphatidylinositol-3 lipid kinase/mammalian target of rapamycin (PI3K/mTOR) signaling pathway, which is abrogated by Rapa at the level of mTOR. Disruption of this GM-CSF signaling pathway induced loss of mitochondrial membrane potential, phosphatidyl-serine exposure, and nuclear changes. Apoptosis of these nonproliferating DCs was preceded by an up-regulation of the cell cycle inhibitor p27KIP1. Overexpression of p27KIP1 in DCs using adenoviral gene transduction revealed that apoptosis is directly regulated by p27KIP1. Furthermore, both overexpression of p27KIP1 and disruption of the GM-CSF/PI3K/mTOR signaling pathway decreased the expression of the antiapoptotic protein mcl-1. This mTOR/p27KIP1/mcl-1 survival seems unique for DCs and may provide novel opportunities to influence immune responses by specific interference with the life span of these cells.
Stem cell factor increases the expression of FLIP that inhibits IFNγ-induced apoptosis in human erythroid progenitor cells
Authors: Chung Ik-Joo , Dai Chunhua , Krantz Sanford B.
Published: January 2003

Interferon γ (IFNγ) acts on human erythroid colony-forming cells (ECFCs) to up-regulate Fas, without a demonstrable change of Fas ligand (FasL) or Fas-associated DD-containing protein (FADD) expression and activates caspase-8 plus caspase-3, which produce apoptosis. Our previous data showed that stem cell factor (SCF) reduced the inhibitory effect of IFNγ on human ECFCs when both factors were present in the cultures. However, the mechanism by which SCF prevents IFNγ-induced apoptosis in ECFCs is unclear. In this study we used highly purified human ECFCs to investigate the mechanism of the effect of SCF on IFNγ-induced apoptosis. Because the binding of FasL to Fas is the first step of the apoptosis cascade and IFNγ strongly up-regulates Fas expression, we added FasL (50 ng/mL) to the cultures with IFNγ to accentuate the IFNγ-induced activation of caspase-8 and caspase-3 plus subsequent apoptosis. SCF (100 ng/mL) clearly inhibited the activation of caspase-8 and caspase-3 induced by IFNγ and/or FasL, and it also reduced apoptosis as measured by the terminal dUTP nick-end labeling (TUNEL) assay. SCF did not decrease the surface expression of Fas on the ECFCs. FADD-like interleukin 1 β (IL-1β)–converting enzyme (FLICE)–inhibitory protein (FLIP) has been reported to interact with FADD and/or caspase-8 at the death-inducing signaling complex (DISC) level following Fas stimulation and acts as a dominant-negative caspase-8. SCF increased FLIP mRNA and protein expression, concomitant with reduced apoptosis, whereas IFNγ and/or FasL did not change FLIP expression. Reduction of FLIP expression with antisense oligonucleotides decreased the capacity of SCF to inhibit IFNγ-induced apoptosis, demonstrating a definite role for FLIP in the SCF-induced protection of ECFCs from IFNγ-initiated apoptosis.
Inhibition of STAT3 signaling induces apoptosis and decreases survivin expression in primary effusion lymphoma
Authors: Aoki Yoshiyasu , Feldman Gerald M. , Tosato Giovanna
Published: January 2003

Despite some exciting new leads in molecular pathogenesis, AIDS-defining primary effusion lymphoma (PEL) remains a fatal malignancy. The lack of substantial progress in the management of PEL demands innovative treatment approaches. Targeting intracellular molecules critical to cell survival is one unexplored strategy for treating PEL. Here we show that inhibition of signal transducer and activator of transcription–3 (STAT3) leads to apoptosis in PEL cells. STAT3 is constitutively phosphorylated in PEL cell lines BC-1, BCBL-1, and VG-1. Transduction of dominant-negative STAT3 and pharmacological STAT3 inhibition caused caspase-dependent cell death. Although STAT3 activation is known to induce expression of Bcl-2 family proteins, PEL cell apoptosis was independent of Bcl-2, Bcl-XL, or Mcl-1 protein expression. Instead, STAT3 inhibition induced transcriptional repression of survivin, a recently identified inhibitor of apoptosis. Forced overexpression of survivin rescued VG-1 cells from apoptosis induced by STAT3 inhibition. Our findings suggest that activated STAT3 signaling directly contributes to malignant progression of PEL by preventing apoptosis, acting through the prosurvival protein survivin. Since constitutive STAT3 activation and survivin expression have been widely documented in different types of cancers, their linkage may extend to many malignancies and be critical to their pathogenesis.
A 20-year perspective on the International Fanconi Anemia Registry (IFAR)
Authors: Kutler David I. , Singh Bhuvanesh , Satagopan Jaya , Batish Sat Dev , Berwick Marianne , Giampietro Philip F. , Hanenberg Helmut , Auerbach Arleen D.
Published: January 2003

Fanconi anemia (FA) is an autosomal recessive disorder characterized by cellular hypersensitivity to DNA cross-linking agents and cancer predisposition. Recent evidence for the interactions of ataxia-telangiectasia mutated protein ATM and breast cancer susceptibility proteins BRCA1 and BRCA2 (identified as FANCD1) with other known FA proteins suggests that FA proteins have a significant role in DNA repair/recombination and cell cycle control. The International Fanconi Anemia Registry (IFAR), a prospectively collected database of FA patients, allows us the unique opportunity to analyze the natural history of this rare, clinically heterogeneous disorder in a large number of patients. Of the 754 subjects in this study, 601 (80%) experienced the onset of bone marrow failure (BMF), and 173 (23%) had a total of 199 neoplasms. Of these neoplasms, 120 (60%) were hematologic and 79 (40%) were nonhematologic. The risk of developing BMF and hematologic and nonhematologic neoplasms increased with advancing age with a 90%, 33%, and 28% cumulative incidence, respectively, by 40 years of age. Univariate analysis revealed a significantly earlier onset of BMF and poorer survival for complementation group C compared with groups A and G; however, there was no significant difference in the time to hematologic or nonhematologic neoplasm development between these groups. Multivariate analysis of overall survival time shows that FANCCmutations (P = .007) and hematopoietic stem cell transplantation (P = < .0001) define a poor-risk subgroup. The results of this study of patients registered in the IFAR over a 20-year period provide information that will enable better prediction of outcome and aid clinicians with decisions regarding major therapeutic modalities.
Additive effect of mouse genetic background and mutation ofMITF gene on decrease of skin mast cells
Authors: Morii Eiichi , Oboki Keisuke , Jippo Tomoko , Kitamura Yukihiko
Published: January 2003

The mi transcription factor (MITF) is a basic-helix-loop-helix leucine zipper transcription factor and is encoded by mi locus. The mi/mi mutant mice showed a significant decrease of skin mast cells in C57BL/6 (B6) genetic background but not in WB genetic background. Kit ligand (KitL) is the most important growth factor for development of mast cells, and the decrease of skin mast cells in B6-mi/mi mice was attributable to the reduced expression of c-kit receptor tyrosine kinase (KIT) that is a receptor for KitL. However, the expression level of KIT in WB-mi/mi mast cells was comparable with that of B6-mi/mi mast cells, suggesting that a factor compensating the reduced expression of KIT was present in WB-mi/mi mice. By linkage analysis, such a factor was mapped on chromosome 10. The mapped position was closely located to the KitL locus. Two alternative spliced forms are known in KitL mRNA: KL-1 and KL-2. Soluble KitL, which is important for development of skin mast cells, is produced more efficiently from KL-1 mRNA than from KL-2 mRNA. The KL-1/KL-2 ratio was higher in WB-mi/mi than in B6-mi/mi mice, suggesting that the larger amount of soluble KitL may compensate for the reduced expression of KIT in WB-mi/mi mice.
Successful therapy of metastatic cancer using tumor vaccines in mixed allogeneic bone marrow chimeras
Authors: Luznik Leo , Slansky Jill E. , Jalla Sanju , Borrello Ivan , Levitsky Hyam I. , Pardoll Drew M. , Fuchs Ephraim J.
Published: January 2003

A frequent outcome of allogeneic stem cell transplantation (alloSCT) in the treatment of leukemia is the destruction of the host hematolymphoid compartment and, thus, the malignancy, through the combined action of high-dose chemoradiotherapy and a T-cell–mediated graft-versus-host effect. Unfortunately, alloSCT is frequently limited by toxicity, including graft-versus-host disease (GVHD), and has not been successful in the treatment of tumors derived from solid organs. Here we report a novel cooperation between host and donor T cells in the response to a tumor cell vaccine given after a nonmyeloablative allogeneic stem cell transplantation (NST) protocol that achieves stable mixed bone marrow chimerism. Treatment of animals with NST, posttransplantation donor lymphocyte infusions (DLIs), and a vaccine, comprising irradiated autologous tumor cells mixed with a granulocyte-macrophage colony-stimulating factor (GM-CSF)–producing bystander line, results in potent and specific antitumor immunity. This combined modality immunotherapy, administered after surgical removal of the primary tumor, cured metastatic mammary cancer in most animals without inducing GVHD. Cured animals contained tumor-specific T cells of both host and donor origin, but immunodeficient hosts could not be cured by NST, DLI, and vaccine administration. Thus, transfer of allogeneic donor T cells may help break functional tolerance of a host immune system to a solid tumor, thereby providing a rationale for the generation of mixed hematopoietic chimerism by NST prior to tumor cell vaccination.
Deletion or replacement of the second EGF-like domain of protein S results in loss of APC cofactor activity
Authors: Mille-Baker Blandine , Rezende Suely M. , Simmonds Rachel E. , Mason Philip J. , Lane David A. , Laffan Michael A.
Published: January 2003

Human protein S (PS), a cofactor of anticoagulant-activated protein C (APC), is a modular protein containing 4 epidermal growth factor (EGF)–like domains. EGF1 appears to mediate PS interaction with APC, but the roles of EGFs 2, 3, and 4 are less clear. We synthesized PS variants lacking single EGF domains (EGF2, 3, or 4) and assessed their APC cofactor activity in a factor Va inactivation assay. The variant lacking EGF2 (variant 134) showed the most dramatic loss of activity (∼10% of recombinant wild-type PS activity). Replacement of EGF2 by an additional EGF3 (variant 1334) resulted in a comparable loss of activity, suggesting that the loss of a specific rather than “spacer” function of EGF2 was responsible. We confirmed that the variant 134 had a functional γ-carboxyglutamic acid (Gla) domain and that EGF1 was correctly folded. This is the first clear evidence that EGF2 is required for the expression of PS activity.
PKD: a new protein kinase C–dependent pathway in platelets
Authors: Stafford Margaret J. , Watson Steve P. , Pears Catherine J.
Published: January 2003

Protein kinase D (PKD, also known as PKCμ) is closely related to the protein kinase C superfamily but is differentially regulated and has a distinct catalytic domain that shares homology with Ca2+-dependent protein kinases. PKD is highly expressed in hematopoietic cells and undergoes rapid and sustained activation upon stimulation of immune receptors. PKD is regulated through phosphorylation by protein kinase C (PKC). In the present study, we show that PKD is expressed in human platelets and that it is rapidly activated by receptors coupled to heterotrimeric G-proteins or tyrosine kinases. Activation of PKD is mediated downstream of PKC. Strong agonists such as convulxin, which acts on GPVI, and thrombin cause sustained activation of PKC and PKD, whereas the thromboxane mimetic U46619 gives rise to transient activation of PKC and PKD. Activation of PKD by submaximal concentrations of phospholipase C–coupled receptor agonists is potentiated by Gi-coupled receptors (eg, adenosine diphosphate and epinephrine). This study shows that PKD is rapidly activated by a wide variety of platelet agonists through a PKC-dependent pathway. Activation of PKD enables phosphorylation of a distinct set of substrates to those targeted by PKC in platelets.
Distinct contributions of TNF and LT cytokines to the development of dendritic cells in vitro and their recruitment in vivo
Authors: Abe Koichiro , Yarovinsky Felix O. , Murakami Takaya , Shakhov Alexander N. , Tumanov Alexei V. , Ito Daisuke , Drutskaya Ludmila N. , Pfeffer Klaus , Kuprash Dmitry V. , Komschlies Kristin L. , Nedospasov Sergei A.
Published: January 2003

TNF/LTα/LTβ (tumor necrosis factor/lymphotoxin-α/lymphotoxin-β) triple knockout (KO) mice show a significant reduction of dendritic cell (DC) number in the spleen, presumably due to defective recruitment and/or production. To distinguish between these possibilities, DCs were generated from bone marrow (BM) cultures prepared from wild-type (wt) and mutant mice in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The yield of CD11c+major histocompatibility complex (MHC) class II+DCs generated from TNF/LTα/LTβ−/− BM culture was significantly reduced compared with wt BM culture. In order to further dissect the individual pathways responsible for defective DC properties observed in TNF/LTα/LTβ−/− mice, the panel of TNF/LT ligand and receptor single KO mice were used. The production of DCs from BM culture was significantly reduced in TNF−/− and TNF receptor (TNFR) p55−/− mice, but normal in LTα−/−, LTβ−/−, LTβR−/−mice. Recombinant TNF (rTNF) exogenously added to TNF/LTα/LTβ−/− BM cultures could reverse this defect, and blocking antibodies showed partial effect on BM cultures of wt mice. Conversely, numbers of mature DCs in spleen were significantly decreased in LTα−/−, LTβ−/−, LTβR−/− mice, but not in TNF−/− and TNFRp55−/− mice. These results reveal 2 distinct contributions of TNF/LT cytokines. First, TNF acting through TNF receptor is involved in the development/maturation of DCs in BM progenitor cultures, but this function appears to be redundant in vivo. Second, the microenvironment in peripheral lymphoid organs associated with LTα/LTβ-LTβR signaling and chemokine production is critical for recruitment efficiency of DCs, and this pathway is indispensable.
Prognosis After Rectal Cancer in Blacks and Whites Participating in Adjuvant Therapy Randomized Trials
Authors: Dignam James J. , Ye Yunrong , Colangelo Linda , Smith Roy , Mamounas Eleftherios P. , Wieand H. Samuel , Wolmark Norman
Published: January 2003

Purpose: National health statistics indicate that blacks have lower survival rates from colorectal cancer than do whites. This disparity has been attributed to differences in stage at diagnosis and other disease features, extent and quality of treatment, and socioeconomic factors. We evaluated outcomes for blacks and whites with rectal cancer who participated in randomized clinical trials of the National Surgical Adjuvant Breast and Bowel Project (NSABP). The randomized trial setting enhances uniformity in disease stage and treatment plan among all participants.

Patients and Methods: The study included black (N = 104) or white (N = 1,070) patients from two serially conducted NSABP randomized trials for operable rectal cancer. Recurrence-free survival and survival were compared using statistical modeling to account for differences in patient and disease characteristics between the groups.

Results: Blacks and whites had largely similar disease features at diagnosis. After adjustment for patient and tumor prognostic covariates, the black/white recurrence hazard ratio (HR) was 1.25 (95% confidence interval [CI], 0.94 to 1.66). The mortality HR was somewhat larger at 1.45 (95% CI = 1.09 to 1.93). Outcomes were improved for both groups in the more recent trial, which employed systemic adjuvant chemotherapy in all treatment arms.

Conclusion: Recurrence-free survival was modestly less favorable for blacks, whereas overall survival was more disparate. Outcomes between groups were more comparable than those noted in national health statistics surveys and other studies. Adequate treatment access and the identification of new prognostic factors that can identify patients at high risk of recurrence are needed to ensure optimal outcomes for rectal cancer patients of all racial/ethnic backgrounds.