bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding Consumer Choices and Preferences in Transaction-Based e-Services
Authors: Iqbal Zafar , Verma Rohit , Baran Roger
Published: August 2003

The rapid increase in transaction-based e-services creates a challenge for firms: What combination of features should they offer to satisfy consumers while realistically considering operational and financial constraints? This article explores the above question by highlighting similarities and differences in consumer preferences between different segments for a transaction-based e-service. The study employs a Web-based discrete choice experiment, in which 1,430 consumers are offered e-service options, differing from each other in terms of non-web-based and online-only features, price per transaction, and marketing promotions. The results demonstrate that overall, consumer preferences for features of transaction-based e-services differ between offline and online consumers. Furthermore, with increase in consumer usage frequency, interesting trends regarding the relative importance for features are observed. Similarities also exist in consumer preferences between various usage-frequency-based consumer segments. The authors believe that these results have both managerial and research implications for design and operations strategy formulation for transaction-based e-services.
The Role of Gender in Reactions to Service Failure and Recovery
Authors: McColl-Kennedy Janet R. , Daus Catherine S. , Sparks Beverley A.
Published: August 2003

Male and female consumers place different emphasis on elements of the service recovery process. Perceptions were influenced by gender of the service provider and by a match of customer and service provider gender. The study, an experimental design with 712 respondents, found that when service providers, irrespective of gender, display concern and give customers voice and a sizable compensation, both men and women reported more positive attitudes compared with when this was not so. Combinations of high voice with high outcome and high voice with high concern were especially important in positively influencing perceptions of effort, regardless of gender. However, the authors also found that there were significant differences between male and female respondents regarding their perceptions of how service recovery should be handled. Women want their views heard during service recovery attempts and to be allowed to provide input. Men, in contrast, do not view voice as important.
Service Failure in Online Retailing
Authors: Holloway Betsy B. , Beatty Sharon E.
Published: August 2003

Organized service recovery policies and programs are important tools to firms in their efforts to maintain satisfied, loyal customers. Although service failure and recovery issues have received considerable attention in the literature, these topics have received only limited attention in the context of online retailing. Specifically, we lack an understanding of the types of online service failures occurring, the success with which firms are recovering from these failures, and consumer reactions to the service failure/recovery encounters they are experiencing. Therefore, this research involves two studies employing both qualitative and quantitative methods with samples of online shoppers to provide an initial examination of the service recovery management of online retailers. The results provide a typology of online service failures and demonstrate a number of areas in which online retailers are failing to effectively manage their service recoveries. The discussion includes implications for online retailers as well as directions for future research.
Do New Digs Mean more Wins?
Authors: Quinn Kevin G. , Bursik Paul B. , Borick Christopher P. , Raethz Lisa
Published: August 2003

Team owners often argue that a new venue will lead to more wins for the team. This premise is examined here by modeling teams as multiproduct, profit-maximizing firms. Teams' competitive quality and playing venues are two inputs in the production of outputs (e.g., game tickets sold, media programming, etc.). The degree of input complementarity or substitutability between competitive quality and venue quality plays a critical role. The authors empirically test the effect of new venues on winning percentage for Major League Baseball (MLB), National Football League (NFL), National Basketball Association (NBA), and National Hockey League (NHL) teams, finding no significant effect except in the case of MLB teams.
Ike and the Interstates: Creeping toward Comprehensive Planning
Authors: Mohl Raymond A.
Published: August 2003

This article explores several aspects of the new interstate highway program during the Eisenhower Era of the 1950s. Federal Interstate legislation left state highway engineers in control of routing and constructing the big new roads that were certain to shape future metropolitan growth patterns. Planning professionals soon criticized the road builders' failure to integrate highway building with metropolitan land use planning, as well as their lack of interest in mass transit alternatives and relocation housing for those displaced by interstate highway construction. Urban renewal legislation required comprehensive planning and relocation provisions, but Eisenhower's economic advisers resisted parallel mandates for the Interstates. Within the Eisenhower administration, however, several key figures were pushing for metropolitan planning, mass transit, and relocation housing. White House domestic adviser Robert E. Merriam and public works planning adviser John S. Bragdon argued the merits of comprehensive planning and uniform requirements for federal construction programs. The stage was set for structural change, policy initiatives that came together in the Highway Act of 1962 and subsequent legislation in the sixties.
Fallopian Tube Cancer
Authors: Johnson Jodie
Published: August 2003

The use of sonography in the evaluation of adnexal masses presents an opportunity for detecting various abnormalities. A case study of primary adenocarcinoma of the fallopian tube is presented. This is one of the rarest malignancies of the female genital tract. Its frequency in relationship to all gynecologic cancers is reported to be 1% or less. As a result, it is not surprising that the diagnosis is rarely made preoperatively. Due to the occurrence rate of this malignancy, the sonographer's opportunity to see this pathological process is limited. The following case illustrates an example of adnexal findings in a “routine” sonographic examination for post-menopausal bleeding.
Jugular Vein Rupture Caused by Invasive Squamous Cell Carcinoma
Authors: Poye Max
Published: August 2003

Sonography is a quick, noninvasive way to evaluate superficial masses. Although the information provided can answer important questions about the nature of these masses, the sonographer must have as much clinical information as possible and make sure that each piece of the puzzle fits and makes sense in relation to the known facts. The value of the information contained in the images will not be maximized if sonographers do not have complete clinical information and the ability to integrate the various components to arrive at an appropriate diagnosis. This case illustrates the need to consider all the possibilities, even when, at first glance, the diagnosis seems obvious. (When you hear hoof beats, it is probably a horse...but it may be a zebra!)
Sonographic Evaluation of Fibromatosis (Aggressive Type) Using Color Doppler Interrogation
Authors: Taggart Robert E. , Kavic Thomas A.
Published: August 2003

Fibromatosis refers to formation of a fibrous or tumor-like nodule or nodular swelling arising from fascia or connective tissue. The behavior of fibromatosis ranges from a self-limiting benign condition to the aggressive or recurrent type. No articles at this time have reported cases of aggressive fibromatosis emphasizing the use of color Doppler sonography for preoperative planning. The authors report two cases of aggressive fibromatosis interrogated with color Doppler imaging and magnetic resonance imaging that correlate with surgical findings.
Sonographic Screening Examinations in Pregnancy
Authors: Zhang Tao
Published: August 2003

There is no consistent evidence of risk caused by sonographic examinations—neither biologic risk for the fetus nor increased use of health services as a result of ascertained conditions. There is also no consistent benefit to routine sonography in terms of important health outcomes. The use of fetal sonography to screen for anomalies reveals evidence that raises substantial concerns regarding interobserver variability. This might be expected when using a test for screening that requires considerable skill. The range of reported sensitivities underscores the disadvantages of performing sonography on a routine basis rather than on selected patients. Pretest counseling may identify a subset of women for whom screening may be effective in improving health outcomes.
Prenatal Sonographic Diagnosis of Congenital Epulis
Authors: Wam Yvonne
Published: August 2003

Sonographic prenatal diagnosis of congenital anomalies has been proven to be an invaluable tool in the management of pregnancy, delivery, and postnatal treatment of affected newborns. Congenital gingival granular cell tumor, or epulis, is a rare intraoral tumor that may cause polyhydramnios and possibly severe respiratory and feeding complications at birth. Sonographic diagnosis of this tumor provides the opportunity to plan the mode of delivery, the presence of support teams to assist in airway maintenance, and surgical correction.
Peg legs andbionic limbs: the development of lower extremity prosthetics
Authors: Gutfleisch Oliver
Published: August 2003

At the 2000 Paralympic Games in Sydney, a new world record for the hundred metre sprint for below knee amputees was set at 11·09 seconds (the current recordfor able bodied athletes is 9·78 seconds). Such an astonishing result is a tribute not only to the talent and determination of the athlete concerned, but also to the part played by high performance lower extremity prostheses. Whilst advances in materials technology have led to improvements in almost all sports, they have altogether revolutionised performance levels in disabled sports. Following a potted history of the evolution of prosthetic devices, this paper reviews relevant aspects of the anatomy of the lower extremity and the biomechanics of human ambulation, and introduces the various components of prosthetic devices. The latest developments in ‘intelligent’ prosthetic devices make use of a magnetorheological fluid which acts as a damper in the knee joint and provides a more natural gait. In addition, a microprocessor embedded inside the prosthesis can enable automatic real time gait control, thus allowing the leg to adapt to different walking speeds and to more demanding environments such as stairs. Some observations are also made on how the self-image of the amputee and the perception of the amputee in society are affected by the functional and aesthetic characteristics of prosthetic equipment.
Changing our environment, changing ourselves: critical realism and transdisciplinary research
Authors: Dickens Peter
Published: August 2003

A number of contemporary issues demand transdisciplinarity, a fusion between insights from different disciplines within some overarching framework. Yet too often in such cases the disciplines continue to talk past each other. This paper focuses on critical realism as a way of coordinating the disciplines. Critical realism provides a view of reality as stratified, with real causal mechanisms operating at the physical, biological, and social levels, and combining with each other to generate the world as experienced. This perspective is applied within a framework which has a long but now somewhat neglected history in social and political thought. As people interact with nature and transform it into the things they need, they finish up transforming their own natures.
Engineering art: the science of concert hall acoustics
Authors: Cox Trevor J. , D'Antonio Peter
Published: August 2003

Modern concert hall design uses science and engineering to make an acoustic which embellishes and enhances the artistry of the musicians. The modern discipline of concert hall acoustics is a little over a hundred years old, and over the last century much has been learnt about how to ensure the audience receives high quality sound. During this period, knowledge from a large number of disciplines has been exploited. It is the intention of this paper to illustrate how disciplines as diverse as X-ray crystallography, psychology, and mobile telephony have influenced acoustic design. The paper will concentrate on the design of acoustic diffusers for concert halls, as this is a topic currently attracting considerable interest within the acoustics industry and academia.
Towards industrial strength philosophy: how analytical ontology can help medical informatics
Authors: Smith Barry , Ceusters Werner
Published: August 2003

Medical research faces a problem of communication. Different communities of medical researchers use different and often incompatible terminologies in expressing the results of their work, and this yields problems of database integration when medical data needs to be entered into computers. Such problems were initially resolved in case by case fashion. Then, however, the idea arose of constructing one single benchmark taxonomy into which all of the various classification systems would need to be translated only once. By serving as a lingua franca for database integration, this taxonomy would ensure that all databases calibrated in its terms would be automatically intercompatible. Interestingly, information scientists called the proposed central classification system an ‘ontology’, and it was soon realised that work on its construction would have more than a few echoes of the metaphysics of old. The present paper describes an attempt to exploit the resources of philosophy in resolving problems which arise specifically in the field of medical terminology integration. It outlines a collaborative venture between the Institute for Formal Ontology and Medical Information Science in Leipzig and the Belgian software company Language & Computing, whereby an ontology based on sound philosophical principles will be tested in the context of powerful software tools for the processing of medical text.
Primary prophylaxis with warfarin prevents thrombosis in paroxysmal nocturnal hemoglobinuria (PNH)
Authors: Hall Claire , Richards Stephen , Hillmen Peter
Published: August 2003

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia in which venous thrombosis is the most common cause of death. Here we address the risk factors for thrombosis and the role of warfarin prophylaxis in PNH. The median follow-up of 163 PNH patients was 6 years (range, 0.2-38 years). Of the patients, 29 suffered thromboses, with a 10-year incidence of 23%. There were 9 patients who presented with thrombosis, and in the remainder the median time to thrombosis was 4.75 years (range, 3 months-15 years). The 10-year risk of thrombosis in patients with large PNH clones (PNH granulocytes > 50%) was 44% compared with 5.8% with small clones (P < .01). Patients with large PNH clones and no contraindication to anticoagulation were offered warfarin. There were no thromboses in the 39 patients who received primary prophylaxis. In comparison, 56 patients with large clones and not taking warfarin had a 10-year thrombosis rate of 36.5% (P = .01). There were 2 serious hemorrhages in more than 100 patient-years of warfarin therapy. Large PNH granulocyte clones are predictive of venous thrombosis, although the exact cut-off for clone size is still to be determined. Primary prophylaxis with warfarin in PNH prevents thrombosis with acceptable risks. (Blood. 2003;102:3587-3591)
Transient down-modulation of CD20 by rituximab in patients with chronic lymphocytic leukemia
Authors: Jilani Iman , O'Brien Susan , Manshuri Taghi , Thomas Deborah A. , Thomazy Vilmos A. , Imam Maha , Naeem Sana , Verstovsek Srdan , Kantarjian Hagop , Giles Francis , Keating Michael , Albitar Maher
Published: August 2003

Lymphoid cells in most patients with chronic lymphocytic leukemia (CLL), when treated with rituximab, become CD20-. This is thought to be due to masking of CD20 by rituximab. We used specific antimouse immunoglobulin antibodies to detect rituximab on the surface of CLL lymphocytes and we demonstrate that rituximab is rarely detectable after therapy. Only 3 of 65 patients with CLL had rituximab detectable on their lymphocytes after rituximab therapy despite the fact that most had no detectable CD20 expression. In vitro mixing of CLL or Raji cells with rituximab demonstrated that rituximab was detectable on the surface of cells due to its binding to CD20. However, the addition of plasma led to the down-modulation of CD20 expression, and the rituximab became undetectable. This down-modulation of CD20 protein expression was associated with a down-modulation of CD20 mRNA. CLL cells that lost their CD20 expression regained CD20 expression after 24 hours in culture. These data suggest that rituximab therapy leads to a substantial but transient down-modulation of CD20 expression and that negativity for CD20 in cells from patients treated with rituximab is not necessarily due to CD20 masking. The importance of this down-modulation in the efficacy of current therapy with rituximab needs further investigation. (Blood. 2003;102: 3514-3520)
Comparative analysis of genes regulated by PML/RARα and PLZF/RARα in response to retinoic acid using oligonucleotide arrays
Authors: Park Dorothy J. , Vuong Peter T. , de Vos Sven , Douer Dan , Koeffler H. Phillip
Published: August 2003

Acute promyelocytic leukemia (APL) is associated with chromosomal translocations involving retinoic acid receptor α (RARα) and its fusion partners including promyelocytic leukemia (PML) and promyelocytic leukemia zinc finger (PLZF). Using oligonucleotide arrays, we examined changes in global gene expression mediated by the ectopic expression of either PML/RARα (retinoid-sensitive) or PLZF/RARα (retinoid-resistant) in U937 cells. Of more than 5000 genes analyzed, 16 genes were commonly up-regulated, and 57 genes were down-regulated by both fusion proteins suggesting their role in the APL phenotype. In our APL model, for example, TNFAIP2, TNFR2, ELF4, RARγ, and HoxA1 were down-regulated by both fusion proteins in the absence of retinoic acid (RA). RA strongly up-regulated these genes in PML/RARα, but not in PLZF/RARα expressing U937 cells. Expression studies in NB4, retinoid-resistant NB4-R2, normal human CD34+ cells, and APL patient samples strongly suggest their role in the regulation of granulocytic differentiation. Furthermore, combined treatment with tumor necrosis factor α (TNFα) and RA synergistically enhanced granulocytic differentiation in NB4 cells but not in NB4-R2 cells. Our data indicate that APL pathogenesis and retinoid-induced granulocytic differentiation of APL cells involve genes in the cell death pathway, and that cooperation between the RA and TNFα signaling pathways exists. Targeting both the retinoid-dependent differentiation and the cell death pathways may improve leukemic therapy, especially in retinoid-resistant acute myeloid leukemia. (Blood. 2003;102:3727-3736)
Physical proximity and functional interplay of PECAM-1 with the Fc receptor FcγRIIa on the platelet plasma membrane
Authors: Thai Le M. , Ashman Leonie K. , Harbour Stacey N. , Hogarth P. Mark , Jackson Denise E.
Published: August 2003

We and others have recently defined that Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1/CD31) functions as a negative regulator of platelet-collagen interactions involving the glycoprotein VI/Fc receptor gamma chain (GPVI/FcR-γ chain) signaling pathway.1,2 In this study, we hypothesized that PECAM-1 may be physically and functionally associated with FcγRIIa on the platelet membrane. The functional relationship between PECAM-1 and FcγRIIa was assessed by determining the effect of anti-PECAM-1 monoclonal antibody Fab fragments on FcγRIIa-mediated platelet aggregation and heparin-induced thrombocytopenia (HITS)-mediated platelet aggregation. Preincubation of washed platelets with monoclonal antibody fragments of 2BD4 directed against PECAM-1 and IV.3 directed against FcγRIIa completely blocked FcγRIIa-mediated platelet aggregation and HITS-mediated platelet aggregation, whereas anti-CD151 antibody had no blocking effect. Coengagement of FcγRIIa and PECAM-1 resulted in negative regulation of FcγRIIa-mediated phospholipase Cγ2 activation, calcium mobilization, and phosphoinositide 3-kinase-dependent signaling pathways. In addition, the physical proximity of FcγRIIa and PECAM-1 was confirmed by using fluorescence resonance energy transfer and coimmunoprecipitation studies. These results indicate that PECAM-1 and FcγRIIa are colocalized on the platelet membrane and PECAM-1 down-regulates FcγRIIa-mediated platelet responses. (Blood. 2003;102:3637-3645)
In human B cells, IL-12 triggers a cascade of molecular events similar to Th1 commitment
Authors: Durali Deniz , de Goër de Herve Marie-Ghislaine , Giron-Michel Julien , Azzarone Bruno , Delfraissy Jean-François , Taoufik Yassine
Published: August 2003

Two functionally distinct subsets of B cells that produce Th1- and Th2-like patterns of cytokines have recently been identified. Interleukin-12 (IL-12) is a critical immunoregulatory cytokine that promotes Th1 differentiation through activation of signal transducer and activator of transcription 4 (STAT4). IL-12 has been reported to induce interferon γ (IFN-γ) production in B cells, but the relevant signaling pathways are poorly documented. Here, in human primary B cells, we found a functional IL-12 receptor (IL-12R) that internalizes following IL-12 binding. IFN-γ and, to a lesser extent, IL-12 positively regulated the IL-12Rβ2 subunit but had no effect on IL-12Rβ1. On examining the effect of IL-12 on STAT4 and T-bet (2 key factors involved in IFN-γ promoter activation), we found that IL-12 induced the phosphorylation and nuclear translocation of STAT4. IL-12-dependent constitutive STAT4 activation was also observed in the Epstein-Barr virus (EBV)-transformed B-cell line RPMI 8866 that spontaneously produces IL-12. T-bet expression has been shown to be dependent on STAT1. IL-12 had no direct effect on STAT1 activation or T-bet expression in primary B cells. In contrast, IL-12-induced IFN-γ led to STAT1 activation, strong expression of T-bet, and IFN-γ expression. IL-12 therefore initiates a cascade of events in B cells, including STAT4 activation, IL-12Rβ2 up-regulation, IFN-γ production, and T-bet up-regulation, potentially leading to Th1-like differentiation. (Blood. 2003;102:4084-4089)
Pivotal role of granulocyte colony-stimulating factor in the development of progenitors in the common myeloid pathway
Authors: Richards Michael K. , Liu Fulu , Iwasaki Hiromi , Akashi Koichi , Link Daniel C.
Published: August 2003

Granulocyte colony-stimulating factor (G-CSF) is the principal cytokine regulating granulopoiesis. G-CSF receptor-deficient mice (G-CSFR-/-) are neutropenic but have only a modest reduction of committed myeloid progenitors. Since it is likely that compensatory mechanisms are induced by the severe neutropenia present in G-CSFR-/- mice, a competitive repopulation assay was performed. These data show that under basal conditions, G-CSF drives nearly all of granulopoiesis through multiple mechanisms. Most importantly, G-CSFR signals regulate the production and/or maintenance of committed-myeloid progenitors. Surprisingly, G-CSFR signals also play a significant role in the regulation of primitive multipotential progenitors in vivo. The contribution of G-CSFR-/- cells to the hematopoietic stem cell compartment is modestly reduced. Moreover, a marked decrease in the contribution of G-CSFR-/- cells to other progenitors in the myeloid pathway, including erythroid and megakaryocytic progenitors, is observed. In contrast, relative to the hematopoietic stem cell compartment, the contribution of G-CSFR-/- cells to the lymphoid lineages is increased. These data suggest that G-CSFR signals may play a role in directing the commitment of primitive hematopoietic progenitors to the common myeloid lineage. Thus, regulation of G-CSF levels may provide a mechanism for directing primitive hematopoietic progenitors into the common myeloid lineage in response to environmental stresses. (Blood. 2003; 102:3562-3568)
Lack of α2-antiplasmin promotes re-endothelialization via over-release of VEGF after vascular injury in mice
Authors: Matsuno Hiroyuki , Ishisaki Akira , Nakajima Keiichi , Okada Kiyotaka , Ueshima Shigeru , Matsuo Osamu , Kozawa Osamu
Published: August 2003

We here report that the arterial blood flow after endothelial injury in mice deficient in α2-antiplasmin (α2-AP-/- mice) was well maintained compared with that of wild-type mice. Moreover, the development of neointima 4 weeks after injury in α2-AP-/- mice was significantly decreased. Histologic observations showed a prompt recovery of endothelial cells with a much higher proliferating index in repaired endothelium in α2-AP-/- mice. The amount of secreted vascular endothelial growth factor (VEGF) by explanted vascular smooth muscle cells (SMCs) from α2-AP-/- mice was significantly increased. In separate experiments using a human endothelial cell (EC) line, we could demonstrate that plasminogen binds to ECs and that this binding can be prevented by α2-AP. Finally, an injection of either an anti-VEGF receptor-1 antibody or α2-AP reduced the prompt endothelial healing. α2-AP is the main inactivator of plasmin, which cleaves extracellular matrix-bound VEGF to release a diffusible proteolytic fragment. Lack of α2-AP, therefore, could lead to a local over-release of VEGF by the continuously active plasmin in the injured area, which could result in a prompt re-endothelialization after vascular injury. Our results provide new insight into the role of α2-AP and VEGF in the pathogenesis of re-endothelialization following vascular injury. (Blood. 2003;102: 3621-3628)
Primary endothelial cells isolated from the yolk sac and para-aortic splanchnopleura support the expansion of adult marrow stem cells in vitro
Authors: Li Weiming , Johnson Scott A. , Shelley William C. , Ferkowicz Michael , Morrison Paul , Li Yanjun , Yoder Mervin C.
Published: August 2003

The embryonic origin and development of hematopoietic and endothelial cells is highly interdependent. We hypothesized that primary endothelial cells from murine yolk sac and para-aortic splanchnopleura (P-Sp) may possess the capacity to expand hematopoietic stem cells (HSCs) and progenitor cells ex vivo. Using Tie2-GFP transgenic mice in combination with fluorochrome-conjugated monoclonal antibodies to vascular endothelial growth factor receptor-2 (Flk1) and CD41, we have successfully isolated pure populations of primary endothelial cells from 9.5-days after coitus (dpc) yolk sac and P-Sp. Adult murine bone marrow Sca-1+c-Kit+lin- cells were cocultured with yolk sac or P-Sp Tie2-GFP+Flk-1+CD41- endothelial cell monolayers for 7 days and the total number of nonadherent cells increased 47- and 295-fold, respectively, and hematopoietic progenitor counts increased 9.4- and 11.4-fold, respectively. Both the yolk sac and P-Sp endothelial cell cocultures facilitated long-term (> 6 months) HSC competitive repopulating ability (2.8- to 9.8-fold increases, respectively). These data suggest that 9.5-dpc yolk sac- and P-Sp-derived primary Tie2-GFP+Flk-1+CD41- endothelial cells possess the capacity to expand adult bone marrow hematopoietic progenitor cell and HSC repopulating ability ex vivo. (Blood. 2003;102:4345-4353)
The proteasome inhibitor bortezomib interacts synergistically with histone deacetylase inhibitors to induce apoptosis in Bcr/Abl+ cells sensitive and resistant to STI571
Authors: Yu Chunrong , Rahmani Mohamed , Conrad Daniel , Subler Mark , Dent Paul , Grant Steven
Published: August 2003

Interactions between the proteasome inhibitor bortezomib and histone deacetylase inhibitors (HDIs) have been examined in Bcr/Abl+ human leukemia cells (K562 and LAMA 84). Coexposure of cells (24-48 hours) to minimally toxic concentrations of bortezomib + either suberoylanilide hydroxamic acid (SAHA) or sodium butyrate (SB) resulted in a striking increase in mitochondrial injury, caspase activation, and apoptosis, reflected by caspases-3 and -8 cleavage and poly(adenosine diphosphate-ribose) polymerase (PARP) degradation. These events were accompanied by down-regulation of the Raf-1/mitogen-induced extracellular kinase (MEK)/extracellular signal-related kinase (ERK) pathway as well as diminished expression of Bcr/Abl and cyclin D1, cleavage of p21CIP1 and phosphorylation of the retinoblastoma protein (pRb), and induction of the stress-related kinases Jun kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Transient transfection of cells with a constitutively active MEK construct significantly protected them from bortezomib/SAHA-mediated lethality. Coadministration of bortezomib and SAHA resulted in increased reactive oxygen species (ROS) generation and diminished nuclear factor κB (NF-κB) activation; moreover, the free radical scavenger L-N-acetylcyteine (LNAC) blocked bortezomib/SAHA-related ROS generation, induction of JNK and p21CIP1, and apoptosis. Lastly, this regimen potently induced apoptosis in STI571 (imatinib mesylate)-resistant K562 cells and CD34+ mononuclear cells obtained from a patient with STI571-resistant disease, as well as in Bcr/Abl- leukemia cells (eg, HL-60, U937, Jurkat). Together, these findings raise the possibility that combined proteasome/histone deacetylase inhibition may represent a novel strategy in leukemia, including apoptosis-resistant Bcr/Abl+ hematologic malignancies. (Blood. 2003;102:3765-3774)
Circadian clock genes oscillate in human peripheral blood mononuclear cells
Authors: Boivin Diane B. , James Francine O. , Wu Aibin , Cho-Park Park F. , Xiong Huabao , Sun Zhong S.
Published: August 2003

In mammals, it is well documented that observable circadian rhythms are controlled by a central oscillator that is organized in transcriptional and translational feedback loops involving several clock genes. Although recent studies have demonstrated that clock genes oscillate in many peripheral tissues, their characteristics in the human immune system remain unknown. The present study investigates whether circadian clock genes function in human peripheral blood mononuclear cells. On the basis of studies derived from 3 human subjects under controlled conditions, circadian clock genes hPer1, hPer2, hPer3, and hDec1 are expressed in a circadian manner in human peripheral blood mononuclear cells (PBMCs), with the peak level occurring during the habitual time of activity. The demonstration of functional circadian machinery in human PBMCs suggests that peripheral blood cells may be useful for the investigation of human circadian rhythms and their associated disorders. (Blood. 2003;102:4143-4145)
Clonal dominance of chronic myelogenous leukemia is associated with diminished sensitivity to the antiproliferative effects of neutrophil elastase
Authors: Ouriaghli Frank El , Sloand Elaine , Mainwaring Lori , Fujiwara Hiroshi , Keyvanfar Keyvan , Melenhorst J. Joseph , Rezvani Katayoun , Sconocchia Giuseppe , Solomon Scott , Hensel Nancy , Barrett A. John
Published: August 2003

Clinical observations suggest that in chronic myelogenous leukemia (CML), the Philadelphia chromosome (Ph+) clone has a growth advantage over normal hematopoiesis. Patients with CML have high levels of neutrophil elastase, which has recently been shown to antagonize the action of granulocyte-colony-stimulating factor (G-CSF) and other growth factors. We therefore compared the effect of elastase on the growth of normal and CML progenitor cells. In 10-day suspension cultures of normal or CML CD34+ cells supplemented with G-CSF, stem cell factor (SCF), and granulocyte macrophage-colony-stimulating factor (GM-CSF), CML cells had diminished sensitivity to the growth inhibitory effect of elastase. When equal numbers of CML and normal CD34+ cells were cocultured for 10 days, there was no change in the relative proportions of normal and leukemic cells (measured by fluorescence in situ hybridization [FISH] or flow cytometry). However, when elastase was added, CML cells predominated at the end of the culture period (78% vs 22% with 1 μg/mL and 80% vs 20% with 5 μg/mL elastase). CML neutrophils substituted effectively for elastase in suppressing the proliferation of normal CD34+ cells, but this effect was abrogated by serine protease inhibitors. These results suggest that elastase overproduction by the leukemic clone can change the growth environment by digesting growth factors, thereby giving advantage to Ph+ hematopoiesis. (Blood. 2003; 102:3786-3792)
Cathepsin-B-dependent apoptosis triggered by antithymocyte globulins: a novel mechanism of T-cell depletion
Authors: Michallet Marie-Cécile , Saltel Frederic , Preville Xavier , Flacher Monique , Revillard Jean-Pierre , Genestier Laurent
Published: August 2003

Antithymocyte globulins (ATGs), the immunoglobulin G (IgG) fraction of sera from rabbits or horses immunized with human thymocytes or T-cell lines, are used in conditioning regimens for bone marrow transplantation, in the treatment of acute graft-versus-host disease, in the prevention or treatment of acute rejection in organ transplantation, and in severe bone marrow aplasia. In nonhuman primates, ATGs induce rapid, dose-dependent, T-cell depletion in peripheral lymphoid tissues, where apoptotic cells can be demonstrated in T-cell zones. We show here that increasing ATG concentrations in vitro resulted in reduced lymphocyte proliferative responses, associated with a rapid increase in the percentage of apoptotic cells. Apoptosis did not require prior exposure to interleukin-2, nor did it result in CD178/CD95 or tumor necrosis factor/tumor necrosis factor receptor (TNF/TNF-R) interactions; it was therefore clearly different from activation-induced cell death. Cytochrome c release, caspase-9, and caspase-3 activation were not implicated, excluding a direct involvement of the intrinsic mitochondrial pathway. The cysteine protease inhibitor E64d and cathepsin-B-specific inhibitors conferred significant protection, whereas apoptosis was associated with the release of active cathepsin B into the cytosol. These data demonstrate a role for cathepsin B in T-cell apoptosis induced by ATGs at concentrations achieved during clinical use. (Blood. 2003; 102:3719-3726)
Identification and characterization of 2 types of erythroid progenitors that express GATA-1 at distinct levels
Authors: Suzuki Norio , Suwabe Naruyoshi , Ohneda Osamu , Obara Naoshi , Imagawa Shigehiko , Pan Xiaoqing , Motohashi Hozumi , Yamamoto Masayuki
Published: August 2003

Transcription factor GATA-1 is essential for the development of the erythroid lineage. To ascertain whether strict control of GATA-1 expression level is necessary for achieving proper erythropoiesis, we established transgenic mouse lines expressing green fluorescent protein (GFP) under the control of the GATA-1 gene hematopoietic regulatory domain. We examined the GATA-1 expression level by exploiting the transgenic mice and found 2 GFP-positive hematopoietic progenitor fractions in the bone marrow. One is the GFPhigh fraction containing mainly CFU-E and proerythroblasts, which coexpress transferrin receptor, while the other is the GFPlow/transferrin receptor-negative fraction containing BFU-E. Since the intensity of green fluorescence correlates well with the expression level of GATA-1, these results indicate that GATA-1 is highly expressed in erythroid colony-forming unit (CFU-E) but low in erythroid burst-forming unit (BFU-E), suggesting that the incremental expression of GATA-1 is required for the formation of erythroid progenitors. We also examined GFP-positive fractions in the transgenic mouse spleen and fetal liver and identified fractions containing BFU-E and CFU-E, respectively. This study also presents an efficient method for enriching the CFU-E and BFU-E from mouse hematopoietic tissues. (Blood. 2003;102:3575-3583)
Functional defects of dendritic cells in patients with CD40 deficiency
Authors: Fontana Stefania , Moratto Daniele , Mangal Surinder , De Francesco Maria , Vermi William , Ferrari Simona , Facchetti Fabio , Kutukculer Necil , Fiorini Claudia , Duse Marzia , Das Pranab K. , Notarangelo Luigi D. , Plebani Alessandro , Badolato Raffaele
Published: August 2003

We have recently identified 2 patients with a rare autosomal recessive form of hyper IgM disease, known as HIGM3, caused by mutations in the CD40 gene. These patients had opportunistic infections observed on X-linked hyper IgM syndrome (HIGM), suggesting that the CD40-CD40 ligand interaction is important for promoting T-cell-mediated immunity. To evaluate whether innate immunity signals may substitute CD154 for inducing the maturation of dendritic cells (DCs), we analyzed monocyte-derived DCs in these patients. Monocyte-derived DCs of HIGM3 subjects on ex vivo stimulation with tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS) combined with interferon-γ (IFN-γ) normally express all the markers of mature DCs, such as CD83 and DC-LAMP. However, cell surface levels of HLA-DR in mature DCs are reduced, as is costimulatory activity of these cells for allogeneic naive T cells. In addition, CD40-deficient DCs secrete lower amounts of interleukin-12 (IL-12) but larger quantities of IL-10 than control subjects. Finally, analysis of circulating plasmacytoid DCs demonstrates a normal percentage of this subset in CD40-deficient cells, but IFN-α secretion in response to herpes simplex virus 1 (HSV-1) infection is severely reduced in patients. These observations suggest that the severe impairment of DC maturation may contribute to the defect of T-cell-mediated immunity observed in HIGM3 patients. (Blood. 2003;102:
Human CD8+CD25+ thymocytes share phenotypic and functional features with CD4+CD25+ regulatory thymocytes
Authors: Cosmi Lorenzo , Liotta Francesco , Lazzeri Elena , Francalanci Michela , Angeli Roberta , Mazzinghi Benedetta , Santarlasci Veronica , Manetti Roberto , Vanini Vittorio , Romagnani Paola , Maggi Enrico , Romagnani Sergio , Annunziato Francesco
Published: August 2003

CD8+CD25+ cells, which expressed high levels of Foxp3, glucocorticoid-induced tumor necrosis factor receptor (GITR), CCR8, tumor necrosis factor receptor 2 (TNFR2), and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) mRNAs, were identified in the fibrous septa and medullary areas of human thymus. Activated CD8+CD25+ thymocytes did not produce cytokines, but most of them expressed surface CTLA-4 and transforming growth factor β1 (TGF-β1). Like CD4+CD25+, CD8+CD25+ thymocytes suppressed the proliferation of autologous CD25-T cells via a contact-dependent mechanism. The suppressive activity of CD8+CD25+ thymocytes was abrogated by a mixture of anti-CTLA-4 and anti-TGF-β1 antibodies and it was mediated by their ability to inhibit the expression of the interleukin 2 receptor α chain on target T cells. These results demonstrate the existence of a subset of human CD8+CD25+ thymocytes sharing phenotype, functional features, and mechanism of action with CD4+CD25+ T regulatory cells. (Blood. 2003;102:4107-4114)
The contributions of the α2β1 integrin to vascular thrombosis in vivo
Authors: He Li , Pappan Loretta K. , Grenache David G. , Li Zhengzhi , Tollefsen Douglas M. , Santoro Samuel A. , Zutter Mary M.
Published: August 2003

The α2β1 integrin serves as a receptor for collagens, laminin, and several other nonmatrix ligands. Many studies have suggested that the α2β1 integrin is a critical mediator of platelet adhesion to collagen within the vessel wall after vascular injury and that the interactions of the platelet α2β1 integrin with subendothelial collagen after vascular injury are required for proper hemostasis. We have used the α2β1 integrin-deficient mouse to evaluate the contributions of the α2β1 integrin in 2 in vivo models of thrombosis. Studies using a model of endothelial injury to the carotid artery reveal that the α2β1 integrin plays a critical role in vascular thrombosis at the blood-vessel wall interface under flow conditions. In contrast, the α2β1 integrin is not required for the formation of thrombi and pulmonary emboli following intravascular injection of collagen. Our results are the first to document a critical in vivo role for the α2β1 integrin in thrombus formation at the vessel wall under conditions of shear following vascular injury. (Blood. 2003;102:3652-3657)
NK-cell purging of leukemia: superior antitumor effects of NK cells H2 allogeneic to the tumor and augmentation with inhibitory receptor blockade
Authors: Koh Crystal Y. , Ortaldo John R. , Blazar Bruce R. , Bennett Michael , Murphy William J.
Published: August 2003

Natural killer (NK) cells are composed of subsets characterized by the expression of inhibitory or activating receptors, or both, specific for different major histocompatibility complex (MHC) class I determinants. We have previously shown that inhibitory receptor blockade of syngeneic NK cells was an effective means of ex vivo purging of leukemia-contaminated bone marrow and that the transplantation of mice with the purged bone marrow cells (BMCs) resulted in long-term, relapse-free survival. We have extended the investigation to assess the antitumor effects mediated by NK cells H2-allogeneic to tumor cells. We demonstrate that various tumor cell lines are more susceptible to lysis by H2-allogeneic NK cells than by syngeneic NK cells in vitro even though comparable percentages of Ly49 NK cells were present. Using allogeneic NK cells to purge leukemia-contaminating BMCs before transplantation resulted in a higher proportion of mice with long-term survival than using syngeneic NK cells. Allogeneic NK cells did not suppress hematopoietic reconstitution as measured by granulocyte/monocyte-colony-forming unit (CFU-GM), complete blood count (CBC), and donor chimerism at various days after transplantation. Inhibitory receptor blockade of allogeneic NK cells also significantly increased these antitumor effects at lower NK/tumor ratios compared with those of syngeneic NK cells. These results demonstrate that H2-allogeneic NK cells mediate more potent antitumor effects than syngeneic NK cells without adverse hematologic effects and thus may be useful in cancer therapy. (Blood. 2003;102:4067-4075)
Multiple integrin-ligand interactions synergize in shear-resistant platelet adhesion at sites of arterial injury in vivo
Authors: Grüner Sabine , Prostredna Miroslava , Schulte Valerie , Krieg Thomas , Eckes Beate , Brakebusch Cord , Nieswandt Bernhard
Published: August 2003

Damage to the integrity of the vessel wall results in exposure of the subendothelial extracellular matrix (ECM), which triggers integrin-dependent adhesion and aggregation of platelets. The role of platelet β1 integrins in these processes remains mostly undefined. Here, we demonstrate by intravital fluorescence microscopy that platelet adhesion and thrombus growth on the exposed ECM of the injured carotid artery is not significantly altered in α2-null mice and even in mice with a Cre/loxP-mediated loss of all β1 integrins on their platelets. In contrast, inhibition of αIIbβ3 integrin on platelets in wild-type mice blocked aggregate formation and reduced platelet adhesion by 60.0%. Strikingly, αIIbβ3 inhibition had a comparable effect in α2-null mice, demonstrating that other receptors mediate shear-resistant adhesion in the absence of functional α2β1 and αIIbβ3. These were identified to be α5β1 and/or α6β1 as αIIbβ3 inhibition abrogated platelet adhesion in β1-null mice. We conclude that shear-resistant platelet adhesion on the injured vessel wall in vivo is a highly integrated process involving multiple integrin-ligand interactions, none of which by itself is essential. (Blood. 2003;102:4021-4027)
Defective RNA ribose synthesis in fibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA)
Authors: Boros László G. , Steinkamp Mara P. , Fleming Judith C. , Lee Wai-Nang Paul , Cascante Marta , Neufeld Ellis J.
Published: August 2003

Fibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA) syndrome with diabetes and deafness undergo apoptotic cell death in the absence of supplemental thiamine in their cultures. The basis of megaloblastosis in these patients has not been determined. Here we use the stable [1,2-13C2]glucose isotope-based dynamic metabolic profiling technique to demonstrate that defective high-affinity thiamine transport primarily affects the synthesis of nucleic acid ribose via the nonoxidative branch of the pentose cycle. RNA ribose isolated from TRMA fibroblasts in thiamine-depleted cultures shows a time-dependent decrease in the fraction of ribose derived via transketolase, a thiamine-dependent enzyme in the pentose cycle. The fractional rate of de novo ribose synthesis from glucose is decreased several fold 2 to 4 days after removal of thiamine from the culture medium. No such metabolic changes are observed in wild-type fibroblasts or in TRMA mutant cells in thiamine-containing medium. Fluxes through glycolysis are similar in TRMA versus control fibroblasts in the pentose and TCA cycles. We conclude that reduced nucleic acid production through impaired transketolase catalysis is the underlying biochemical disturbance that likely induces cell cycle arrest or apoptosis in bone marrow cells and leads to the TRMA syndrome in patients with defective high-affinity thiamine transport. (Blood. 2003;102: 3556-3561)
Plasticity of marrow-derived stem cells
Authors: Herzog Erica L. , Chai Li , Krause Diane S.
Published: August 2003

Bone marrow (BM) contains hematopoietic stem cells (HSCs), which differentiate into every type of mature blood cell; endothelial cell progenitors; and marrow stromal cells, also called mesenchymal stem cells (MSCs), which can differentiate into mature cells of multiple mesenchymal tissues including fat, bone, and cartilage. Recent findings indicate that adult BM also contains cells that can differentiate into additional mature, nonhematopoietic cells of multiple tissues including epithelial cells of the liver, kidney, lung, skin, gastrointestinal (GI) tract, and myocytes of heart and skeletal muscle. Experimental results obtained in vitro and in vivo are the subject of this review. The emphasis is on how these experiments were performed and under what conditions differentiation from bone marrow to epithelial and neural cells occurs. Questions arise regarding whether tissue injury is necessary for this differentiation and the mechanisms by which it occurs. We also consider which bone marrow subpopulations are capable of this differentiation. Only after we have a better understanding of the mechanisms involved and of the cells required for this differentiation will we be able to fully harness adult stem cell plasticity for clinical purposes. (Blood. 2003; 102:3483-3493)