bluuebunny/crossref_metadata_2025 huggingface dataset:
Interleukin (IL)-15Rα–deficient Natural Killer Cells Survive in Normal but Not IL-15Rα–deficient Mice
Authors: Koka Rima , Burkett Patrick R. , Chien Marcia , Chai Sophia , Chan Faye , Lodolce James P. , Boone David L. , Ma Averil
Published: April 2003

Natural killer (NK) cells protect hosts against viral pathogens and transformed cells. IL-15 is thought to play a critical role in NK cell development, but its role in the regulation of peripheral NK cells is less well defined. We now find that adoptive transfer of normal NK cells into mice lacking the high affinity interleukin (IL)-15 receptor, IL-15Rα, surprisingly results in the abrupt loss of these cells. Moreover, IL-15Rα–deficient NK cells can differentiate successfully in radiation bone marrow chimera bearing normal cells. Finally, adoptively transferred IL-15Rα–deficient NK cells survive in normal but not IL-15Rα–deficient mice. These findings demonstrate that NK cell–independent IL-15Rα expression is critical for maintaining peripheral NK cells, while IL-15Rα expression on NK cells is not required for this function.
CD40 Signaling Is Impaired in L. major–infected Macrophages and Is Rescued by a p38MAPK Activator Establishing a Host-protective Memory T Cell Response
Authors: Awasthi Amit , Mathur Ramkumar , Khan Aslam , Joshi Bimba N. , Jain Nitya , Sawant Sangeeta , Boppana Ramanamurthy , Mitra Debashis , Saha Bhaskar
Published: April 2003

Leishmania, a protozoan parasite, lives and multiplies as amastigote within macrophages. It is proposed that the macrophage expressed CD40 interacts with CD40 ligand on T cells to induce IFN-γ, a Th1-type cytokine that restricts the amastigote growth. Here, we demonstrate that CD40 cross-linking early after infection resulted in inducible nitric oxide synthetase type-2 (iNOS2) induction and iNOS2-dependent amastigote elimination. Although CD40 expression remained unaltered on L. major–infected macrophages, delay in the treatment of macrophages or of mice with anti-CD40 antibody resulted in significant reduction in iNOS2 expression and leishmanicidal function suggesting impaired CD40 signaling in Leishmania infection. The inhibition of CD40-induced iNOS2 expression by SB203580, a p38-mitogen activated protein kinase (p38MAPK)-specific inhibitor, and the reversal of the inhibition by anisomycin, a p38MAPK activator, suggested a crucial role of p38MAPK in CD40 signaling. Indeed, the CD40-induced p38MAPK phosphorylation, iNOS2 expression and anti-leishmanial function were impaired in Leishmania-infected macrophages but were restored by anisomycin. Anisomycin's effects were reversed by SB203580 emphasizing the role of p38MAPK in CD40-induced iNOS2-dependent leishmanicidal function. Anisomycin administration in L. major–infected BALB/c mice resulted in significant reduction in the parasite load and established a host-protective Th1-type memory response. Also implicated in these findings is a scientific rationale to define novel anti-parasite drug targets and to bypass the problem of drug resistance.
Transformation of Sporozoites into Early Exoerythrocytic Malaria Parasites Does Not Require Host Cells
Authors: Kaiser Karine , Camargo Nelly , Kappe Stefan H.I.
Published: April 2003

Malaria parasite species that infect mammals, including humans, must first take up residence in hepatic host cells as exoerythrocytic forms (EEF) before initiating infection of red blood cells that leads to malaria disease. Despite the importance of hepatic stages for immunity against malaria, little is known about their biology and antigenic composition. Here, we show that sporozoites, the parasites' transmission stage that resides in the mosquito vector salivary glands, can transform into early EEF without intracellular residence in host hepatocytes. The morphological sequence of transformation and the expression of proteins in the EEF appear indistinguishable from parasites that develop within host cells. Transformation depends on temperature elevation to 37°C and serum. Our findings demonstrate that residence in a host hepatocyte or specific host cell–derived factors are not necessary to bring about the profound morphological and biochemical changes of the parasite that occur after its transmission from vector to mammalian host.
To Participate or Not to Participate: The Link Between Survey Participation, Electoral Participation, and Political Interest
Authors: Voogt Robert J. J. , Saris Willem E.
Published: April 2003

Survey participation, electoral participation, and political interest have been given wide attention in the research literature, but no one so far has combined these three variables in one model. Taking the social isolation-hypothesis as our starting point, we developed a model with one factor, social involvement, as the common factor underlying these three types of participation. We reviewed the literature and concluded that we had to include a second underlying factor: attachment to society. Using a new data set, gathered on the occasion of the 1998 Dutch national elections and including validated voter turnout measures, we were able to test the model. After making some adaptions, we found a model with a satisfactory fit. The results show that, by including social involvement and attachment to society as mediating variables, we can reach much higher levels of explained variances of survey and electoral participation than we can with traditional models. The results also add to our understanding of the relationship between survey and electoral participation and political interest.
Internal and External Effects on the Accuracy of NES Turnout: Reply
Authors: Burden Barry C.
Published: April 2003

In an earlier issue of this journal I brought attention to the fact that estimates of voter turnout in U.S. presidential elections from the National Election Study (NES) series have been increasingly biased. Although researchers had already noted that the NES overestimated turnout, I was concerned with the growing severity of the problem. While admitting that other factors were at work, my explanation centered on the representativeness of surveys, in particular that selection bias in the sample is correlated with the likelihood of voting (Burden 2000). Martinez (2003) and McDonald (2003) offer three possible additions to my argument. First, panel effects are responsible for particularly egregious discrepancies in a few presidential elections, particularly in the 1996 survey. Second, official turnout statistics that rely on the Voting Age Population (VAP) are themselves biased and lack perfect comparability with the NES. Third, the degree of misreporting might also depend on actual voter turnout.
Correlation Versus Interchangeability: The Limited Robustness of Empirical Findings on Democracy Using Highly Correlated Data Sets
Authors: Casper Gretchen , Tufis Claudiu
Published: April 2003

This article shows that highly correlated measures can produce different results. We identify a democratization model from the literature and test it in more than 120 countries from 1951 to 1992. Then, we check whether the results are robust regarding measures of democracy, time periods, and levels of development. The findings show that measures do matter: Whereas some of the findings are robust, most of them are not. This explains, in part, why the debates on democracy have continued rather than been resolved. More important, it underscores the need for more careful use of measures and further testing to increase confidence in the findings. Scholars in comparative politics are drawn increasingly to large-N statistical analyses, often using data sets collected by others. As in any field, we show how they must be careful in choosing the most appropriate measures for their studies, without assuming that any correlated measure will do.
The Speed of Light: Making an Easy Time of It
Authors: Brody Burt
Published: April 2003

Time-of-flight measurements of the speed of light in air are conceptually easy. The outgoing modulated light from a HeNe laser and the returned light from a distant reflector may be sampled using two photodetectors. The two signals can be displayed on a reasonably fast dual-trace oscilloscope to determine the transit time. In practice, however, obtaining a satisfactory return beam from the distant mirror can be difficult. I have found that, with a few hours of setup time, a common garden reflector may be used as the distant “mirror,” along with a large plastic Fresnel lens to collect the somewhat dispersed returned light, to determine the speed of light in air to within 10%.
Some Pivotal Thoughts on the Current Balance
Authors: Fletcher K. A. , Iyer S. V. , Kinsey K. F.
Published: April 2003

The current balance is an excellent device for demonstrating the force on a current-carrying wire. By considering the electrons flowing through the wires and applying some geometrical analysis, we can gain a better understanding of why the wire moves, how the current is distributed in the wires, and why the simplifying assumptions of the force law apply to this realistic situation.
Estimating the Earth's Magnetic Field Strength with an Extension Cord
Authors: Berger Roland , Schmitt Markus
Published: April 2003

While rotating an extension cord in the Earth's magnetic field, an electric voltage is induced at its ends. This simple setup leads to an estimation of the Earth's magnetic field's strength in a basic electrodynamics course.
Some Simple Black Hole Thermodynamics
Authors: LoPresto Michael C.
Published: April 2003

In his recent popular book The Universe in a Nutshell, Steven Hawking gives expressions for the entropy1 and temperature (often referred to as the “Hawking temperature”2 ) of a black hole:3 S = kc34ℏG A T = ℏc38πkGM, where A is the area of the event horizon, M is the mass, k is Boltzmann's constant, ℏ = h2π (h being Planck's constant), c is the speed of light, and G is the universal gravitational constant. These expressions can be used as starting points for some interesting approximations on the thermodynamics of a Schwarzschild black hole, of mass M, which by definition is nonrotating and spherical with an event horizon of radius R = 2GMc2.4,5
Doing Science
Authors: Blanton Patricia
Published: April 2003

At a recent conference on “Linking science in the classroom to science in the laboratory,” Timothy Slater of the University of Arizona reminded the attendees that science is a verb and that science is constructed by those who do it. As he emphasized the need for using real data for doing and teaching science, I thought about the ways we introduce concepts to students and the tasks we ask them to perform.
QUANTUM MARKOV FIELDS
Authors: ACCARDI LUIGI , FIDALEO FRANCESCO
Published: April 2003

The Markov property for quantum lattice systems is investigated in terms of generalized conditional expectations. General properties of (particular cases of) quantum Markov fields, i.e. quantum Markov processes with multi-dimensional indices, are pointed out. In such a way, deep connections with the KMS boundary condition, as well as phenomena of phase transitions and symmetry breaking, naturally emerge.
Pulmonary Vein Anatomy in Patients Undergoing Catheter Ablation of Atrial Fibrillation
Authors: Kato Ritsushi , Lickfett Lars , Meininger Glenn , Dickfeld Timm , Wu Richard , Juang George , Angkeow Piamsook , LaCorte Jennifer , Bluemke David , Berger Ronald , Halperin Henry R. , Calkins Hugh
Published: April 2003

Background—

This study sought to define the technique and results of magnetic resonance imaging (MRI) of pulmonary vein (PV) anatomy before and after catheter ablation of atrial fibrillation (AF).

Methods and Results—

Twenty-eight patients with AF underwent ablation. Patients underwent gadolinium-enhanced MRI before and 6 weeks after their procedures. A control group of 27 patients also underwent MRI. Variant PV anatomy was observed in 38% of patients. AF patients had larger PV diameters than control subjects, but no difference was observed in the size of the PV ostia among AF patients. The PV ostia were oblong in shape with an anteroposterior dimension less than the superoinferior dimension. The left PVs had a longer “neck” than the right PVs. A detectable PV narrowing was observed in 24% of veins. The severity of stenosis was severe in 1 vein (1.4%), moderate in 1 vein (1.4%), and mild in 15 veins (21.1%). All patients were asymptomatic, and none required treatment.

Conclusions—

This study demonstrates that AF patient have larger PVs than control subjects and demonstrates the value of MRI in facilitating AF ablation. The benefits of preprocedural MRI of PVs include the ability to evaluate the number, size, and shape of the PVs. MRI also provides an assessment of the severity of PV stenosis.
Angiographic Assessment of Collateral Connections in Comparison With Invasively Determined Collateral Function in Chronic Coronary Occlusions
Authors: Werner Gerald S. , Ferrari Markus , Heinke Stephan , Kuethe Friedhelm , Surber Ralf , Richartz Barbara M. , Figulla Hans R.
Published: April 2003

Background—

The evaluation of new therapeutic modalities to induce collateral growth in coronary artery disease require improved methods of angiographic characterization of collaterals, which should be validated by quantitative assessment of collateral function.

Methods and Results—

In 100 patients with total chronic occlusion of a major coronary artery (duration >2 weeks) collaterals were assessed angiographically by the Rentrop grading, by their anatomic location, and by a new grading of collateral connections (CC grade 0: no continuous connection, CC1: threadlike continuous connection, CC2: side branch–like connection). The interobserver variability was 10%. Collateral function was assessed by Doppler flow (average peak velocity) and pressure recordings distal to the occlusion before recanalization. A collateral resistance index (R
Coll
) was calculated. Recruitable collateral flow was measured during a final balloon inflation >30 minutes after the baseline measurement. The comparison of the anatomic location, the Rentrop, and the collateral connection grade showed only for the latter an independent and significant relation with R
Coll
. CC2 collaterals preserved regional left ventricular function better than did CC1 collaterals and provided a higher collateral flow reserve during adenosine infusion. CC0 collaterals were predominantly observed in recent occlusions of 2 to 4 weeks’ duration, with the highest R
Coll
. During balloon reocclusion, recruitable collateral function was best preserved with CC2 and least with CC0.

Conclusions—

The angiographic grading of collateral connections in total chronic occlusions could differentiate collaterals according to their functional capacity to preserve regional left ventricular function and was closely associated with invasively determined parameters of collateral hemodynamics.
Probucol Promotes Functional Reendothelialization in Balloon-Injured Rabbit Aortas
Authors: Lau Antony K. , Leichtweis Steven B. , Hume Peter , Mashima Ryuichi , Hou Jing Y. , Chaufour Xavier , Wilkinson Barbara , Hunt Nicholas H. , Celermajer David S. , Stocker Roland
Published: April 2003

Background—

Probucol remains the only conventional drug that reduces restenosis after coronary angioplasty. Apart from its weak cholesterol-lowering effect, probucol has antioxidant properties, but it remains unclear how this drug inhibits restenosis.

Methods and Results—

Aortic balloon-injured New Zealand White rabbits were fed 2% (wt/wt) cholesterol-enriched or normal chow, with 0.75% (wt/wt) probucol (P) or without (controls, C) for 6 weeks. Endothelial denudation of the abdominal aorta was performed at week 3 with a 3F Fogarty embolectomy catheter. The arteries were harvested after week 6 and analyzed for histology, lipids and antioxidants, and endothelial regeneration and function. Probucol significantly decreased aortic intima-to-media ratio (cholesterol-fed: C, 1.10±0.08 versus P, 0.70±0.10; normal: C, 0.89±0.02 versus P, 0.83±0.05;
P
<0.05) and the numbers of proliferating intimal smooth muscle cells and lowered serum cholesterol without altering the proportion of aortic lipids that was oxidized. Probucol promoted endothelial regeneration in the injured aorta in cholesterol-fed rabbits (25% increase in reendothelialization,
P
<0.05) and in those on normal chow (37% increase,
P
<0.01). This was associated with both improved endothelial function as assessed by enhanced aortic ring relaxation and cGMP production in response to acetylcholine and decreased intimal thickening.

Conclusions—

Probucol inhibits intimal thickening in balloon-damaged arteries of rabbits by promoting the regeneration of functional endothelium, without affecting the proportion of aortic lipids that was oxidized. This novel in vivo finding helps explain how probucol inhibits restenosis after coronary angioplasty and highlights potential new targets for therapeutic intervention.
Effect of Atrial Fibrillation and an Irregular Ventricular Response on Sympathetic Nerve Activity in Human Subjects
Authors: Wasmund Stephen L. , Li Jian-Ming , Page Richard L. , Joglar Jose A. , Kowal Robert C. , Smith Michael L. , Hamdan Mohamed H.
Published: April 2003

Background—

Although the hemodynamic changes associated with atrial fibrillation (AF) have been extensively studied, the neural changes remain unclear. We hypothesized that AF is associated with an increase in sympathetic nerve activity (SNA) and that the irregular ventricular response contributes to this state of sympathoexcitation.

Methods and Results—

In 8 patients referred for an electrophysiological study, SNA, blood pressure (BP), central venous pressure (CVP), and heart rate were recorded during 3 minutes of normal sinus rhythm (NSR) and 3 minutes of induced AF. In 5 of 8 patients who converted to NSR, right atrial (RA) pacing was performed for 3 minutes in atrial pacing triggered by ventricular sensing mode triggered by playback of an FM tape previously recorded from the right ventricle during AF (RA-irregular) and atrial pacing inhibited by atrial sensing mode at a rate equal to the mean heart rate obtained during AF (RA-regular). SNA data were expressed as percentage of baseline during NSR. SNA increased in all 8 patients during induced AF compared with NSR (171±40% versus 100%, respectively;
P
<0.01). This was associated with a trend for a decrease in BP and an increase in CVP (
P
=0.02). Similarly, SNA was significantly higher during RA-irregular pacing compared with RA-regular pacing (124±24% versus 91±20%, respectively;
P
=0.03). BP and CVP were not significantly different between the 2 pacing modes.

Conclusions—

Induced AF results in a significant increase in SNA, which is in part attributable to the irregular ventricular response. Our findings suggest that restoring NSR or regularity might be beneficial, particularly in patients with heart failure.
Effect of Cardiac Resynchronization Therapy on Left Ventricular Size and Function in Chronic Heart Failure
Authors: St John Sutton Martin G. , Plappert Ted , Abraham William T. , Smith Andrew L. , DeLurgio David B. , Leon Angel R. , Loh Evan , Kocovic Dusan Z. , Fisher Westby G. , Ellestad Myrvin , Messenger John , Kruger Kristin , Hilpisch Kathryn E. , Hill Michael R.S.
Published: April 2003

Background—

Cardiac resynchronization therapy (CRT) has recently emerged as an effective treatment for patients with moderate to severe systolic heart failure and ventricular dyssynchrony. The purpose of the present study was to determine whether improvements in left ventricular (LV) size and function were associated with CRT.

Methods and Results—

Doppler echocardiograms were obtained at baseline and at 3 and 6 months after therapy in 323 patients enrolled in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Of these, 172 patients were randomized to CRT on and 151 patients to CRT off. Measurements were made of LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, severity of mitral regurgitation (MR), peak transmitral velocities during early (E-wave) and late (A-wave) diastolic filling, and the myocardial performance index. At 6 months, CRT was associated with reduced end-diastolic and end-systolic volumes (both
P
<0.001), reduced LV mass (
P
<0.01), increased ejection fraction (
P
<0.001), reduced MR (
P
<0.001), and improved myocardial performance index (
P
<0.001) compared with control. β-Blocker treatment status did not influence the effect of CRT. Improvements with CRT were greater in patients with a nonischemic versus ischemic cause of heart failure.

Conclusions—

CRT in patients with moderate-to-severe heart failure who were treated with optimal medical therapy is associated with reverse LV remodeling, improved systolic and diastolic function, and decreased MR. LV remodeling likely contributes to the symptomatic benefits of CRT and may herald improved longer-term survival.
β
2
-Adrenergic Receptor Polymorphisms and Risk of Incident Cardiovascular Events in the Elderly
Authors: Heckbert Susan R. , Hindorff Lucia A. , Edwards Karen L. , Psaty Bruce M. , Lumley Thomas , Siscovick David S. , Tang Zhonghua , Durda J. Peter , Kronmal Richard A. , Tracy Russell P.
Published: April 2003

Background—

Genetic polymorphisms at codons 16 and 27 of the β
2
-adrenergic receptor have been associated with altered response to sympathetic stimulation. We examined these polymorphisms in relation to cardiovascular event risk in the Cardiovascular Health Study.

Methods and Results—

A total of 808 black and 4441 white participants (mean age, 73 years) were genotyped for the Arg16Gly and Gln27Glu polymorphisms of the β
2
-adrenergic receptor. There were 702 incident coronary events, 438 ischemic strokes, and 1136 combined cardiovascular events during 7 to 10 years of follow-up. Allele frequencies differed by race but not by age or hypertension status. Glu27 carriers had a lower risk of coronary events than Gln27 homozygotes (hazard ratio, 0.82; 95% CI, 0.70 to 0.95), and there was a suggestion of decreased risk among Gly16 carriers compared with Arg16 homozygotes (hazard ratio, 0.88; 95% CI, 0.72 to 1.07). There was no association of β
2
-adrenergic receptor genotype with ischemic stroke or combined cardiovascular events.

Conclusions—

The Glu27 allele of the β
2
-adrenergic receptor was associated with a lower risk of incident coronary events in this elderly population.
BCR/ABL alters the function of NK cells and the acquisition of killer immunoglobulin-like receptors (KIRs)
Authors: Chiorean Elena G. , Dylla Scott J. , Olsen Krista , Lenvik Todd , Soignier Yvette , Miller Jeffrey S.
Published: April 2003

Natural killer (NK) cells decrease in function during chronic myelogenous leukemia (CML) progression from chronic phase to blast crisis, and they can becomeBCR/ABL+ late in the disease course. To study this altered function, NK92 cells were transduced with the BCR/ABL oncogene. In contrast to the parental cells, which died when deprived of interleukin 2 (IL-2), p210+ NK92 cells proliferated and survived indefinitely in the absence of IL-2. BCR/ABL also decreased the natural cytotoxicity of NK92 cells against K562 targets, without affecting IL-2, interferon γ (IFN-γ), or tumor necrosis factor α (TNF-α) production. Although the ABL-specific tyrosine kinase inhibitor imatinib mesylate (STI-571) had no effect on parental NK92 cells, it markedly decreased the growth and survival of IL-2–independent p210+ NK92 cells. In contrast to the parental cell line, serial analysis of p210+ NK92 cells detected small populations that clonally expressed one or more killer immunoglobulin-like receptors (KIRs). Unlike the decreased natural cytotoxicity, the function of the activating CD158j receptor remained intact. Southern blotting and hybridization with an enhanced green fluorescence protein (eGFP) probe showed that KIR− and KIR+ NK92 cells were all derived from the same clone, suggesting that KIR acquisition remains dynamic at the maturational stage represented by the NK92 cell line. When tested in primary CD56+bright NK cells, p210 induced partial IL-2–independent growth and increased KIR expression similar to findings in NK92 cells. This is the first study to show thatBCR/ABL, well known for its effects on the myeloid lineage, can alter the function of lymphoid cells, which may be associated with the defect in innate immunity associated with CML progression.
Gamma-delta T-cell phenotype is associated with significantly decreased survival in cutaneous T-cell lymphoma
Authors: Toro Jorge R. , Liewehr David J. , Pabby Nina , Sorbara Lynn , Raffeld Mark , Steinberg Seth M. , Jaffe Elaine S.
Published: April 2003

The importance of αβ versus γδ T-cell subset antigen expression in the classification of peripheral T-cell lymphomas is still unclear. The objective of this study was to investigate the prognostic value of T-cell receptor–δ1 (TCRδ1) expression in primary cutaneous T-cell lymphomas. TCRδ1 cellular expression was assessed in skin biopsy specimens of 104 individuals with cutaneous T-cell lymphoma by immunohistochemistry. Both univariate (Kaplan-Meier) and multivariate (Cox regression) analyses were conducted to determine which variables (T-cell subtype, hemophagocytosis, histologic profile, age, sex, and adenopathy) were significantly associated with survival. Univariate analysis indicated that there was a statistically significant difference in survival between the patients with αβ cutaneous T-cell lymphoma and patients with γδ cutaneous T-cell lymphoma (P < .0001). There was also a statistically significant decrease in survival among patients who had subcutaneous involvement compared with patients who had epidermotropic and/or dermal involvement (P < .0001). Cox model analysis indicated that TCRδ1 expression was the factor that was most closely associated with decreased survival (P < .0001). Among those patients with cutaneous γδ T-cell lymphoma (n = 33), there was a trend for decreased survival for patients who had histologic evidence of subcutaneous fat involvement in comparison with patients who had epidermotropic or dermal patterns of infiltration (P = .067). No other prognostic factors were identified as having a notable association with outcome in this subgroup. TCRδ1 expression in primary cutaneous lymphomas is an independent prognostic factor associated with decreased survival.
Role of the intracellular domains of GPIb in controlling the adhesive properties of the platelet GPIb/V/IX complex
Authors: Perrault Christelle , Mangin Pierre , Santer Martine , Baas Marie-Jeanne , Moog Sylvie , Cranmer Susan L. , Pikovski Inna , Williamson David , Jackson Shaun P. , Cazenave Jean-Pierre , Lanza François
Published: April 2003

Glycoprotein (GP) Ib/V/IX complex–dependent platelet adhesion to von Willebrand factor (VWF) is supported by the 45-kd N-terminal extracellular domain of the GPIbα subunit. Recent results with an adhesion blocking antibody (RAM.1) against GPIbβ, which is disulfide linked to GPIbα, have suggested a novel function of this subunit in regulating VWF-mediated platelet adhesion, possibly involving its intracellular face. A putative cooperation between the GPIbα and GPIbβ cytoplasmic domains was investigated by measuring the adhesion under flow to immobilized VWF of K562 and Chinese hamster ovary (CHO) cells transfected with GPIb/(V)/IX containing mutations in this region. Adhesion of cells carrying a glycine substitution of the GPIbβ Ser166 phosphorylation site was 50% lower than normal and became insensitive to inhibition by RAM.1. In contrast, forskolin or PGE1 treatment increased both the phosphorylation of GPIbβ and adhesion of control cells, both effects being reversed by RAM.1, but had no influence on cells expressing the Ser166Gly mutation. A role of the GPIbα intracellular domain was also apparent as the VWF-dependent adhesion of cells containing deletions of the entire (Δ518-610) or portions (Δ535-568, Δ569-610) of the GPIbα cytoplasmic tail was insensitive to RAM.1 inhibition. Cells carrying progressive 11 amino acid deletions spanning the GPIbα 535-590 region were equally unresponsive to RAM.1, with the exception of those containing GPIbα Δ569-579, which behaved like control cells. These findings support a role of the GPIbβ intracellular domain in controlling the adhesive properties of the GPIb/V/IX complex through phosphorylation of GPIbβ Ser166 and point to the existence of cross-talk between the GPIbβ and GPIbα intracellular domains.
Gene expression profile in human leukocytes
Authors: Hashimoto Shin-ichi , Nagai Shigenori , Sese Jun , Suzuki Takuji , Obata Aya , Sato Taku , Toyoda Nobuaki , Dong Hong-Yan , Kurachi Makoto , Nagahata Tomoyuki , Shizuno Ken-ichi , Morishita Shinichi , Matsushima Kouji
Published: April 2003

Leukocytes are classified as myelocytic or lymphocytic, and each class of leukocytes consists of several types of cells that have different phenotypes and different roles. To define the gene expression in these cells, we have performed serial analysis of gene expression (SAGE) using human leukocytes and have provided the gene database for these cells not only at the resting stage but also at the activated stage. A total of 709 990 tags from 17 libraries were analyzed for the manifestation of gene expression profiles in various types of human leukocytes. Types of leukocytes analyzed were as follows: peripheral blood monocytes, colony-stimulating factor–induced macrophages, monocyte-derived immature dendritic cells, mature/activated dendritic cells, granulocytes, natural killer (NK) cells, resting B cells, activated B cells, naive T cells, CCR4− memory T cells (resting TH1 cells), CCR4+ memory T cells (resting TH2 cells), activated TH1 cells, and activated TH2 cells. Among 38 961 distinct tags that appeared more than once in the combined total libraries, 27 323 tags were found to represent unique genes in certain type(s) of leukocytes. Using probability (P) and hierarchical clustering analysis, we identified the genes selectively expressed in each type of leukocytes. Identification of the genes specifically expressed in different types of leukocytes provides not only a novel molecular signature to define different subsets of resting and activated cells but also contributes to further understanding of the biologic function of leukocytes in the host defense system.
A naturally occurring Tyr143HisαIIb mutation abolishes αIIbβ3 function for soluble ligands but retains its ability for mediating cell adhesion and clot retraction: comparison with other mutations causing ligand-binding defects
Authors: Kiyoi Teruo , Tomiyama Yoshiaki , Honda Shigenori , Tadokoro Seiji , Arai Morio , Kashiwagi Hirokazu , Kosugi Satoru , Kato Hisashi , Kurata Yoshiyuki , Matsuzawa Yuji
Published: April 2003

The molecular basis for the interaction between a prototypic non–I-domain integrin, αIIbβ3, and its ligands remains to be determined. In this study, we have characterized a novel missense mutation (Tyr143His) in αIIb associated with a variant of Glanzmann thrombasthenia. Osaka-12 platelets expressed a substantial amount of αIIbβ3(36%-41% of control) but failed to bind soluble ligands, including a high-affinity αIIbβ3-specific peptidomimetic antagonist. Sequence analysis revealed that Osaka-12 is a compound heterozygote for a single 521T>C substitution leading to a Tyr143His substitution in αIIb and for the null expression of αIIb mRNA from the maternal allele. Given that Tyr143 is located in the W3 4-1 loop of the β-propeller domain of αIIb, we examined the effects of Tyr143His or Tyr143Ala substitution on the expression and function of αIIbβ3 and compared them with KO (Arg-Thr insertion between 160 and 161 residues of αIIb) and with the Asp163Ala mutation located in the same loop by using 293 cells. Each of them abolished the binding function of αIIbβ3 for soluble ligands without disturbing αIIbβ3 expression. Because immobilized fibrinogen and fibrin are higher affinity/avidity ligands for αIIbβ3, we performed cell adhesion and clot retraction assays. In sharp contrast to KO mutation and Asp163AlaαIIbβ3, Tyr143HisαIIbβ3-expressing cells still had some ability for cell adhesion and clot retraction. Thus, the functional defect induced by Tyr143HisαIIb is likely caused by its allosteric effect rather than by a defect in the ligand-binding site itself. These detailed structure–function analyses provide better understanding of the ligand-binding sites in integrins.
Hematopoietic progenitor kinase 1 (HPK1) negatively regulates prostaglandin E2–induced fos gene transcription
Authors: Sawasdikosol Sansana , Russo Kristin M. , Burakoff Steven J.
Published: April 2003

Prostaglandin E2 (PGE2) is the predominant eicosanoid product released by macrophages at the site of inflammation. Binding of PGE2 to its cognate 7 transmembrane-spanning G protein–coupled receptors (GPCRs) activates signaling pathways, leading to the synthesis of the Fos transcription factor. Because the Ste20 serine/threonine protein kinase (S/TPK) is a critical signal transducer for the G protein–coupled pheromone receptor in Saccharomyces cerevisiae, we postulated that the PGE2 GPCRs may activate one of the Ste20 mammalian orthologs. We demonstrate here that the catalytic activity of a hematopoietic cell–restricted, Ste20-related S/TPK, HPK1, is positively regulated by exposure to physiological concentrations of PGE2. Furthermore, ectopic expression studies implicated HPK1 as a negative regulator of PGE2-induced transcription of the fos gene. Our data suggest that PGE2-induced activation of HPK1 may represent a novel negative regulatory pathway capable of modulating PGE2-mediated gene transcription.
Acceleration of idiopathic pneumonia syndrome (IPS) in the absence of donor MIP-1α (CCL3) after allogeneic BMT in mice
Authors: Panoskaltsis-Mortari Angela , Hermanson John R. , Taras Elizabeth , Wangensteen O. Douglas , Serody Jonathan S. , Blazar Bruce R.
Published: April 2003

Idiopathic pneumonia syndrome (IPS) is a significant cause of morbidity and mortality after bone marrow transplantation (BMT) in humans. We developed a murine IPS model in which lethal pre-BMT conditioning and allogeneic T cells results in the recruitment of host monocytes and then donor T cells into the lung by day 7 after BMT, concomitant with development of severe lung dysfunction. We reported the T cell–dependent production of the T cell–attracting chemokine macrophage inflammatory protein-1α (MIP-1α) in the lungs of such recipient mice. We reasoned that MIP-1α might be a critical mediator of IPS. Lethally conditioned mice received transplants of major histocompatibility complex–disparate marrow and either wild-type (MIP-1α+/+) or knockout (MIP-1α−/−) spleen cells. Recipients of MIP-1α−/− cells exhibited accelerated mortality and a decrease in specific compliance that appeared earlier than in recipients of MIP-1α+/+ cells. Donor CD4+ and CD8+ T cell expansion was increased in the spleens of recipients of MIP-1α−/−cells. Lungs of recipients of MIP-1α−/− cells had earlier recruitment of both T-cell subsets by day 3 after BMT, concomitant with the influx of cells expressing the cytolysins granzymes A and B. Monocyte recruitment was not altered. Levels of inflammatory cytokines were not increased and levels of T cell–attracting chemokines were decreased. The level of the anti-inflammatory cytokine interleukin 13 (IL-13) was lower in the serum and lungs of recipients of MIP-1α−/− cells, indicating a skewing toward a more inflammatory T helper cell type 1 (Th1) cytokine milieu. Donor-derived MIP-1α may play a role in allogeneic-induced IPS by limiting aggressive expansion of CD4+ and CD8+ T cells.
Two histone deacetylase inhibitors, trichostatin A and sodium butyrate, suppress differentiation into osteoclasts but not into macrophages
Authors: Rahman Md. Mizanur , Kukita Akiko , Kukita Toshio , Shobuike Takeo , Nakamura Takahiro , Kohashi Osamu
Published: April 2003

Histone deacetylase (HDAC) inhibitors are emerging as a new class of anticancer therapeutic agents and have been demonstrated to induce differentiation in some myeloid leukemia cell lines. In this study, we show that HDAC inhibitors have a novel action on osteoclast differentiation. The effect of 2 HDAC inhibitors, trichostatin A (TSA) and sodium butyrate (NaB), on osteoclastogenesis was investigated using rat and mouse bone marrow cultures and a murine macrophage cell line RAW264. Both TSA and NaB inhibited the formation of preosteoclast-like cells (POCs) and multinucleated osteoclast-like cells (MNCs) in rat bone marrow culture. By reverse transcription-polymerase chain reaction analysis, TSA reduced osteoclast-specific mRNA expression of cathepsin K and calcitonin receptor (CTR). In contrast, TSA and NaB did not affect the formation of bone marrow macrophages (BMMs) induced by macrophage colony-stimulating factor as examined by nonspecific esterase staining. Fluorescence-activated cell sorting analysis showed that TSA did not affect the surface expression of macrophage markers for CD11b and F4/80 of BMMs. TSA and NaB also inhibited osteoclast formation and osteoclast-specific mRNA expression in RAW264 cells stimulated with receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL). Transient transfection assay revealed that TSA and NaB dose dependently reduced the sRANKL-stimulated or tumor necrosis factor α (TNF-α)–stimulated transactivation of NF-κB–dependent reporter genes. The treatment of RAW264 cells with TSA and NaB inhibited TNF-α–induced nuclear translocation of NF-κB and sRANKL-induced activation of p38 mitogen-activated protein kinase (MAPK) signals. These data suggest that both TSA and NaB exert their inhibitory effects by modulating osteoclast-specific signals and that HDAC activity regulates the process of osteoclastogenesis.
Induction of tumor necrosis factor by bryostatin 1 is involved in synergistic interactions with paclitaxel in human myeloid leukemia cells
Authors: Wang Shujie , Wang Zhiliang , Dent Paul , Grant Steven
Published: April 2003

Interactions between the protein kinase C (PKC) activator/down-regulator bryostatin 1 and paclitaxel have been examined in human myeloid leukemia cells (U937) and in highly paclitaxel-resistant cells ectopically expressing a Bcl-2 phosphorylation loop–deleted protein (ΔBcl-2). Treatment (24 hours) of wild-type cells with paclitaxel (eg, 5 to 20 nM) in combination with 10 nM bryostatin 1 induced a marked increase in mitochondrial damage (eg, cytochrome c and Smac/DIABLO [second mitochondria-derived activator of caspases/direct IAP binding protein with low pI] release), caspase activation, Bid cleavage, and apoptosis; moreover, bryostatin 1 circumvented the block to paclitaxel-induced mitochondrial injury and apoptosis conferred by ectopic expression of the loop-deleted protein. Coadministration of tumor necrosis factor (TNF) soluble receptors, or ectopic expression of CrmA or dominant-negative caspase-8, abrogated potentiation of paclitaxel-induced mitochondrial injury and apoptosis by bryostatin 1, implicating the extrinsic apoptotic pathway in this process. Similar events occurred in HL-60 leukemia cells. Potentiation of paclitaxel-induced apoptosis in wild-type and mutant cells by bryostatin 1 was associated with increases in TNF-α mRNA and protein and was mimicked by exogenous TNF-α. Coadministration of the selective PKC inhibitor GFX (1 μM) blocked the increase in TNF-α mRNA levels and apoptosis in bryostatin 1/paclitaxel–treated cells. Lastly, synchronization of cells in G2M increased their sensitivity to TNF-α–associated lethality. Collectively, these findings indicate that in U937 cells, bryostatin 1 promotes paclitaxel-mediated mitochondrial injury and apoptosis, and circumvents resistance to cell death conferred by loss of the Bcl-2 phosphorylation domain, through the PKC-dependent induction of TNF-α. They further suggest that this process is amplified by paclitaxel-mediated arrest of cells in G2M, where they are more susceptible to TNF-α–induced lethality.
Prenatal diagnosis for congenital afibrinogenemia caused by a novel nonsense mutation in the FGB gene in a Palestinian family
Authors: Neerman-Arbez Marguerite , Vu Dung , Abu-Libdeh Bassam , Bouchardy Isabelle , Morris Michael A.
Published: April 2003

Congenital afibrinogenemia is a rare autosomal recessive disorder characterized by the complete absence of detectable fibrinogen. We previously identified the first causative mutations for this disease, homozygous deletions of approximately 11 kb of the fibrinogen alpha chain gene (FGA). Subsequent analyses revealed that most afibrinogenemia alleles are truncating mutations of FGA, although mutations in all 3 fibrinogen genes, FGG, FGA andFGB have been identified. In this study, we performed the first prenatal diagnosis for afibrinogenemia. The causative mutation in a Palestinian family was a novel nonsense mutation in theFGB gene, Trp467Stop (W467X). Expression of the Trp467Stop mutant FGB cDNA in combination with wild-typeFGA and FGG cDNAs showed that fibrinogen molecules containing the mutant beta chain are not secreted into the media. The fetus was found to be heterozygous for the Trp467Stop mutation by direct sequencing and by linkage analysis, a result that was confirmed in the newborn by intermediate fibrinogen levels.
Late relapses evolve from slow-responding subclones in t(12;21)-positive acute lymphoblastic leukemia: evidence for the persistence of a preleukemic clone
Authors: Konrad Marianne , Metzler Markus , Panzer Simon , Östreicher Iris , Peham Martina , Repp Reinald , Haas Oskar A. , Gadner Helmut , Panzer-Grümayer E. Renate
Published: April 2003

TEL/AML1-positive childhood acute lymphoblastic leukemias (ALLs) generally have low-risk features, but still about 20% of patients relapse. Our initial molecular genetic analyses in 2 off-treatment relapses suggested that the initial and relapse clones represent different subclones that evolved from a common TEL/AML1-positive, treatment-resistant precursor. In order to further elaborate on this hypothesis, we studied 2 patients with late systemic relapses of their TEL/AML1-positive ALL (41 months and 49 months after initial diagnosis, respectively) who had distinct clonal antigen receptor gene rearrangements at diagnosis and relapse. These clone-specific markers enabled us to determine the responsiveness of the individual clones to treatment. The matching genomic TEL/AML1 breakpoints of the initial and the relapse clones in these patients confirmed their origin from a common progenitor cell. This proof was especially important in one of these 2 leukemias without a common antigen receptor gene rearrangement. Our retrospective analysis revealed that in both cases the relapse clone was already present at diagnosis. Despite their small sizes (5 × 10−3 and 1 × 10−4, respectively), we were able to detect their much slower responses to therapy compared with the dominant leukemic clone. Moreover, in all instances, these initially slow-responding clones, after they had developed into the relapse leukemia, were rapidly eradicated by the relapse treatment, underlining their different biology at the 2 time points of leukemia manifestation. We thus hypothesize that the minor clone was not fully malignant at initial diagnosis but acquired further mutations that may be necessary for the manifestation of relapse.
The PML gene is not involved in the regulation of MHC class I expression in human cell lines
Authors: Bruno Silvia , Ghiotto Fabio , Fais Franco , Fagioli Marta , Luzi Lucilla , Pelicci Pier Giuseppe , Grossi Carlo Enrico , Ciccone Ermanno
Published: April 2003

The promyelocytic leukemia gene, PML, is a growth and transformation suppressor. An additional role forPML as a regulator of major histocompatibility complex (MHC) class I antigen presentation has been proposed in a murine model, which would account for evasion from host immunity of tumors bearing malfunctioning PML, such as acute promyelocytic leukemia. Here we investigated a possible role ofPML for the control MHC class I expression in human cells. PML function was perturbed in human cell lines either byPML/RARα transfection or by PML- specific RNA interference. Impairment of wild-type PML function was proved by a microspeckled disassembly of nuclear bodies (NBs), where the protein is normally localized, or by their complete disappearance. However, no MHC class I down-regulation was observed in both instances. We next constructed a PML mutant, PML mut ex3,that is a human homolog of the murine PML mutant, truncated in exon 3, that was shown to down-regulate murine MHC class I. PML mut ex3 transfected in human cell lines exerted a dominant-negative effect since no PML molecules were detected in NBs but, instead, in perinuclear and cytoplasmic larger dotlike structures. Nevertheless, no down-regulation of MHC class I expression was evident. Moreover, neither transfection with PML mut ex3 nor PML-specific RNA interference affected the ability of γ-interferon to up-regulate MHC class I expression. We conclude that, in human cell lines, PML is not involved directly in the regulation of MHC class I expression.
Activating mutations of RTK/ras signal transduction pathway in pediatric acute myeloid leukemia
Authors: Meshinchi Soheil , Stirewalt Derek L. , Alonzo Todd A. , Zhang Quangeng , Sweetser David A. , Woods William G. , Bernstein Irwin D. , Arceci Robert J. , Radich Jerald P.
Published: April 2003

Activating mutations of receptor tyrosine kinases (RTKs) and their downstream affectors are common in acute myeloid leukemia (AML). We performed mutational analysis of FLT3, c-kit, c-fms, vascular endothelial growth factor (VEGF) receptors (Flt-1, KDR [kinase domain receptor]), and ras genes in a group of 91 pediatric patients with AML treated on Children's Cancer Group clinical trial CCG-2891. Forty-six percent of patients had activating mutations of FLT3 (24.5%), c-kit (3%), or ras (21%) genes. Mutation-positive patients had a higher median diagnostic white blood cell (WBC) count (71.5 vs 19.6 × 109/L; P = .005) and lower complete remission rate (55% versus 76%; P = .046) than mutation-negative patients. The Kaplan-Meier estimate of overall survival (OS) for patients with and without an activating mutation was 34% versus 57%, respectively (P = .035). However, within this group, patients with FLT3/ALM (activation loop mutation) had good outcomes (OS, 86%). Exclusion of the FLT3/ALM from analysis decreased the OS for the remaining mutation-positive patients to 26% (P = .003). Ten of the 23 mutation-positive and 11 of the 34 mutation-negative patients received an allogeneic bone marrow transplant (BMT) in first complete remission (CR). In the mutation-positive group, the disease-free survival (DFS) for the allogeneic BMT recipients was 72% versus 23% for the 13 patients who received chemotherapy or autologous BMT (P = .01). DFS for the mutation-free patients with and without allogeneic BM transplantation was 55% and 40%, respectively (P = .38). Activating mutations in the RTK/ras signaling pathway are common in pediatric AML, and their presence may identify a population at higher risk of poor outcome who may benefit from allogeneic BM transplantation.
Variation in dynamic elastic shear modulus of sandstone upon fluid saturation and substitution
Authors: Khazanehdari Jalal , Sothcott Jeremy
Published: April 2003

Experimental acoustic measurements on sandstone rocks at both sonic and ultrasonic frequencies show that fluid saturation can cause a noticeable change in both the dynamic bulk and shear elastic moduli of sandstones. We observed that the change in dynamic shear modulus upon fluid saturation is highly dependent on the type of saturant, its viscosity, rock microstructure, and applied pressures. Frequency dispersion has some influence on dynamic elastic moduli too, but its effect is limited to the ultrasonic frequency ranges and above. We propose that viscous coupling, reduction in free surface energy, and, to a limited extent, frequency dispersion due to both local and global flow are the main mechanisms responsible for the change in dynamic shear elastic modulus upon fluid saturation and substitution, and we quantify influences.