bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants of Handicap After Stroke
Authors: Sturm Jonathan W. , Donnan Geoffrey A. , Dewey Helen M. , Macdonell Richard A.L. , Gilligan Amanda K. , Thrift Amanda G.
Published: February 2004

Background and Purpose—

Handicap, although more relevant to the patient than impairment or disability, has received little attention in people with stroke. The aim of this study was to identify, in an unselected population, factors determining handicap at 2 years after stroke.

Methods—

All first-ever cases of stroke in a population of 306 631 over a 1-year period were assessed. Stroke severity, comorbidity, and demographic information was recorded. Among survivors, 2-year poststroke handicap was assessed with the London Handicap Scale. Disability, physical impairment, depression, anxiety, living arrangements, and recurrent stroke at 2 years were documented. If necessary, proxy assessments were obtained, except for mood. Linear regression analyses were performed to identify factors independently associated with handicap. First, all assessments (proxy and nonproxy) were examined; then, the nonproxy assessments were used to examine the effects of mood.

Results—

Of 266 patients with incident stroke who were alive at 2 years, 226 (85%) were assessed. Significant determinants of handicap on univariable analysis were age, female sex, socioeconomic status, alcohol intake, stroke subtype, initial stroke severity; 2-year physical impairment, disability, depression and anxiety scores; institutionalization; and recurrent stroke. On multivariable analysis, the independent determinants of handicap were age and 2-year physical impairment and disability. In analysis restricted to nonproxy data, depression and anxiety were also independently associated with handicap.

Conclusions—

Age, concurrent disability, and physical impairment were more important determinants of handicap than other demographic factors or initial stroke severity. Because depression and anxiety were independently associated with handicap, their treatment may potentially reduce handicap in stroke patients.
Glucose but Not Lactate in Combination With Acidosis Aggravates Ischemic Neuronal Death In Vitro
Authors: Cronberg Tobias , Rytter Anna , Asztély Fredrik , Söder Anna , Wieloch Tadeusz
Published: February 2004

Background and Purpose—

Hyperglycemia aggravates brain damage in clinical stroke and in experimental in vivo models of cerebral ischemia. Elevated preischemic glucose levels, lactate production, and intracerebral acidosis correlate with increased brain damage. We have developed a murine hippocampal slice culture model of in vitro ischemia (IVI), suitable for studies of the mechanisms of neuronal death. In this model we investigated the individual contribution of glucose, pH, lactate, and combinations thereof as well as ionotropic glutamate receptor activation to the development of hyperglycemic ischemic cell death.

Methods—

Murine organotypic hippocampal slice cultures were exposed to IVI in a medium with an ionic composition similar to that of the extracellular fluid in the brain during ischemia in vivo. Cell death was assessed by propidium iodide uptake. Ionotropic glutamate receptor blockade was accomplished by
d
-2-amino-5-phosphonopentanoic acid (D-APV) or 2,3-dihydro-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX).

Results—

The combination of high glucose levels and acidosis (pH 6.8), but not acidosis per se or the combination of lactate and acidosis during IVI, exacerbated damage. Cell death after hyperglycemic IVI was not diminished by blockade of ionotropic glutamate receptors.

Conclusions—

Aggravation of brain damage by hyperglycemia in vivo can be reproduced in hippocampal slice cultures in vitro. Our results demonstrate that glucose per se, but not lactate, in combination with acidosis mediates the detrimental hyperglycemic effect through a mechanism independent of ionotropic glutamate receptors.
Planet Earth in Contemporary Electronic Artworks
Authors: Knebusch Julien
Published: February 2004

This article presents an overall view of contemporary electronic artworks related to Planet Earth as a topic of artistic inquiry. The author presents and interprets philosophically the different ways in which artists have approached Planet Earth and tried to reappropriate this object of modernity. In order to do so he outlines a phenomenological reading of these artworks and confronts them with the well-established phenomenological discourse about humans' relationship to Planet Earth
The Earth Music of Thamkrabok Monastery
Authors: Kaempfer Phra Hans Ulrich , Pinkel Sheila
Published: February 2004

Since 1981, Luang Paw Charoen Panchard, Abbot of Thamkrabok Monastery in the Lopburi province of Thailand, has created music based on shapes found in nature. Cracks in walls, stones or the soil are traced onto transparent plastic sheets and transformed into musical notes. Luang Paw believes that the process of making this earth music results in spiritual healing and growth
Heart Rate Sonification: A New Approach to Medical Diagnosis
Authors: Ballora Mark , Pennycook Bruce , Ivanov Plamen C. , Glass Leon , Goldberger Ary L.
Published: February 2004

Ever since 1819, when Theophile Laënnec first put a block of wood to a patient's chest in order to listen to her heartbeat, physicians have used auscultation to help diagnose cardiopulmonary disorders. Here the authors describe a novel diagnostic method based in music technology. Digital music-synthesis software is used to transform the sequence of time intervals between consecutive heartbeats into an electroacoustic soundtrack. The results show promise as a diagnostic tool and also provide the basis of an interesting musical soundscape.
The Digital Art of Marbled Paper
Authors: Akgun B. Tevfik
Published: February 2004

The author describes his development of a computer-based paper-marbling tool, based on a traditional Turkish art form in which marbled-paper figures and patterns are created on the surface of a liquid bath. Similar works can be obtained by simulating fluid flows on a computer, using the Navier-Stokes equations as the physical model of the fluid flows. The author has created an application program that includes marbling tools. Such a program must run in real time, so that hand-eye coordination is required of the user. Real-time simulation of fluid flows requires much processor power. The author has attempted to adapt this technique for use with a personal computer. To decrease the processing power required, the image size may be decreased, but the results may not be as satisfactory
A Universal Grammar for Visual Composition?
Authors: Stebbing Peter D.
Published: February 2004

The author has identified four fundamental organizational principles common to both organic form and the creation of visual composition. The author proposes that our perceptual system has evolved to respond to these principles (perceptual primitives) due to the necessity of recognizing the diversity of organic forms on which our survival depended during our earlier evolution. The evidence shows that these four principles occur widely throughout humankind's aesthetic expression in different cultures, epochs, art forms and media. Applying von Humboldt's principle, the author proposes that these limited means provide unlimited possibilities for developing student creativity if it were taught as a coherent grammar
Lethal Ambiguity
Authors: McGinnis Martha
Published: February 2004

This article argues for a new analysis of Rizzi's (1986) Chain Condition effects, which accounts for the absence of such effects in some derivations. Under the proposed analysis, each moved phrase must be unambiguously linkedwith its copy at LF. Otherwise, a lethal ambiguity arises, and the derivation crashes. The syntactic position (address) and the numeration index of an A-movedphrase are usedto link it with its copy. Long A-movement across another DP can arise in two ways: via an EPP-driven derivation that gives rise to a lethal ambiguity, and via a Case-driven derivation that does not.
Double Objects Again
Authors: Beck Sigrid , Johnson Kyle
Published: February 2004

In this article, we explore the interaction of the verb again with double object constructions and the corresponding NP+PP constructions. The restitutive reading that again gives rise to in combination with these predicates supports an analysis of double object constructions according to which they contain a small clause with a head predicate HAVE, and an analysis of the corresponding NP+PP constructions that is not transformationally related and varies according to the verb contained in the structures
A Note on Weakest Crossover
Authors: Ruys E. G.
Published: February 2004

Conditions on variable binding are of two types:those that (roughly) require a pronoun to be A-bound, and those that ban locally ā-bound pronouns. While the two types are usually felt to be extensionally equivalent, argue here on the basis of weakest crossover that the former type, which fits the Minimalist Program better, is also empiri cally superior.
The role of apoptosis in the development of AGM hematopoietic stem cells revealed by Bcl-2 overexpression
Authors: Orelio Claudia , Harvey Kirsty N. , Miles Colin , Oostendorp Robert A. J. , van der Horn Karin , Dzierzak Elaine
Published: February 2004

Apoptosis is an essential process in embryonic tissue remodeling and adult tissue homeostasis. Within the adult hematopoietic system, it allows for tight regulation of hematopoietic cell subsets. Previously, it was shown that B-cell leukemia 2 (Bcl-2) overexpression in the adult increases the viability and activity of hematopoietic cells under normal and/or stressful conditions. However, a role for apoptosis in the embryonic hematopoietic system has not yet been established. Since the first hematopoietic stem cells (HSCs) are generated within the aortagonad-mesonephros (AGM; an actively remodeling tissue) region beginning at embryonic day 10.5, we examined this tissue for expression of apoptosis-related genes and ongoing apoptosis. Here, we show expression of several proapoptotic and antiapoptotic genes in the AGM. We also generated transgenic mice overexpressing Bcl-2 under the control of the transcriptional regulatory elements of the HSC marker stem cell antigen-1 (Sca-1), to test for the role of cell survival in the regulation of AGM HSCs. We provide evidence for increased numbers and viability of Sca-1+ cells in the AGM and subdissected midgestation aortas, the site where HSCs are localized. Most important, our in vivo transplantation data show that Bcl-2 overexpression increases AGM and fetal liver HSC activity, strongly suggesting that apoptosis plays a role in HSC development.
Mechanisms of early peripheral CD4 T-cell tolerance induction by anti-CD154 monoclonal antibody and allogeneic bone marrow transplantation: evidence for anergy and deletion but not regulatory cells
Authors: Kurtz Josef , Shaffer Juanita , Lie Ariadne , Anosova Natalie , Benichou Gilles , Sykes Megan
Published: February 2004

Anti-CD154 (CD40L) monoclonal antibody (mAb) plus bone marrow transplantation (BMT) in mice receiving CD8 cell-depleting mAb leads to long-term mixed hematopoietic chimerism and systemic donor-specific tolerance through peripheral and central deletional mechanisms. However, CD4+ T-cell tolerance is demonstrable in vitro and in vivo rapidly following BMT, before deletion of donor-reactive CD4 cells is complete, suggesting the involvement of other mechanisms. We examined these mechanisms in more detail. Spot enzyme-linked immunosorbent (ELISPOT) analysis revealed specific tolerization (within 4 to 15 days) of both T helper 1 (Th1) and Th2 cytokine responses to the donor, with no evidence for cytokine deviation. Tolerant lymphocytes did not significantly down-regulate rejection by naive donor-reactive T cells in adoptive transfer experiments. No evidence for linked suppression was obtained when skin expressing donor alloantigens in association with third-party alloantigens was grafted. T-cell receptor (TCR) transgenic mixing studies revealed that specific peripheral deletion of alloreactive CD4 T cells occurs over the first 4 weeks following BMT with anti-CD154. In contrast to models involving anti-CD154 without BMT, BMT with anti-CD154 leads to the rapid induction of anergy, followed by deletion of pre-existing donor-reactive peripheral CD4+ T cells; the rapid deletion of these cells obviates the need for a regulatory cell population to suppress CD4 cell-mediated alloreactivity. (Blood. 2004;103:4336-4343)
Clinical management of thrombophilia-related placental vascular complications
Authors: Brenner Benjamin
Published: February 2004

Pregnancy is a hypercoagulable state with an increased thrombotic risk throughout gestation and the postpartum period. Women with thrombophilia may have a further increased risk of placental vascular complications, including pregnancy loss, preeclampsia, intrauterine growth restriction, and placental abruption. Preliminary data suggest that maternal antithrombotic prophylaxis may result in improved gestational outcome. Randomized trials are under way and hopefully will optimize maternal and neonatal outcome.
Effect of chronic cytokine therapy on clonal dynamics in nonhuman primates
Authors: Kuramoto Ken , Follmann Dean A. , Hematti Peiman , Sellers Stephanie , Agricola Brian A. , Metzger Mark E. , Donahue Robert E. , von Kalle Christof , Dunbar Cynthia E.
Published: February 2004

Hematopoietic cytokines such as filgrastim are used extensively to stimulate granulocyte production or to mobilize hematopoietic progenitors into the circulation; however, their effect on more primitive hematopoietic progenitor and stem cells in vivo is unknown, particularly in large animals or humans. In particular, there is concern that chronic therapy with cytokines could result in stem cell exhaustion or clonal dominance; however, direct assessment of the dynamics of individual stem and progenitor cell clones in vivo has not been previously reported. A number of models can be proposed regarding the mechanisms by which the marrow responds to cytokine stimulation, including recruitment of previously quiescent clones, stimulation of proliferation of already active clones, or prevention of apoptosis of more mature progenitors from all clones. Using retroviral marking and comprehensive insertion site tracking of individual stem and progenitor cell clones in 2 rhesus macaques, we analyzed the effect of chronic administration of granulocyte colony-stimulating factor (G-CSF), or a combination of G-CSF plus stem cell factor (SCF). The overall number of contributing clones remained constant, and the relative output from each clone did not change significantly during or following cytokine treatments. These results suggest that individual transduced stem or progenitor cells can contribute to hematopoiesis for prolonged periods, with no evidence for an effect of G-CSF or G-CSF/SCF on the number, the lifespan, or the relative activity of individual stem or progenitor cell clones. These relevant large animal studies are reassuring regarding clinical applications of cytokines and provide new insights into their mechanisms of action.
Engraftment of NOD/SCID-β2 microglobulin null mice with multilineage neoplastic cells from patients with myelodysplastic syndrome
Authors: Thanopoulou Eleni , Cashman Johanne , Kakagianne Theodora , Eaves Allen , Zoumbos Nicholas , Eaves Connie
Published: February 2004

The development of immunodeficient mouse xenograft models has greatly facilitated the investigation of some human hematopoietic malignancies, but application of this approach to the myelodysplastic syndromes (MDSs) has proven difficult. We now show that cells from most MDS patients (including all subtypes) repopulate nonobese diabetic-severe combined immunodeficient (scid)/scid-β2 microglobulin null (NOD/SCID-β2m-/-) mice at least transiently and produce abnormal differentiation patterns in this model. Normal marrow transplants initially produce predominantly erythroid cells and later predominantly B-lymphoid cells in these mice, whereas most MDS samples produced predominantly granulopoietic cells. In 4 of 4 MDS cases, the regenerated cells showed the same clonal markers (trisomy 8, n = 3; and 5q-, n = 1) as the original sample and, in one instance, regenerated trisomy 8+ B-lymphoid as well as myeloid cells were identified. Interestingly, the enhanced growth of normal marrow obtained in NOD/SCID-β2m-/- mice engineered to produce human interleukin-3, granulocyte-macrophage colony-stimulating factor, and Steel factor was seen only with 1 of 7 MDS samples. These findings support the concept that human MDS originates in a transplantable multilineage hematopoietic stem cell whose genetic alteration may affect patterns of differentiation and responsiveness to hematopoietic growth factors. They also demonstrate the potential of this new murine xenotransplant model for future investigations of MDS. (Blood. 2004;103:4285-4293)
Low dendritic cell count after allogeneic hematopoietic stem cell transplantation predicts relapse, death, and acute graft-versus-host disease
Authors: Reddy Vijay , Iturraspe Jose A. , Tzolas Alessandra C. , Meier-Kriesche Herwig-Ulf , Schold Jesse , Wingard John R.
Published: February 2004

Dendritic cells (DCs) are key antigen-presenting cells with a potential role in tumor vaccines. We investigated the hypothesis that early reconstitution of DCs after allogeneic hematopoietic stem cell transplantation (SCT) improves survival. We also correlated DC reconstitution with complications of relapse and acute graft-versus-host disease (aGVHD). Fifty patients underwent transplantation between February 2000 and March 2003, with a median follow-up of 501 days (range, 136-1263 days). Most (92%) received blood stem cells, and the remainder received bone marrow from HLA-matched sibling donors for predominantly high-risk hematologic malignancies. Around the time of engraftment, peripheral blood underwent flow cytometry analysis for DCs, and the cells were divided as DC1 and DC2. Using Kaplan-Meier analysis, patients with lower DC counts (< 4.97 cells/μL) were found to have significantly worse survival (P = .002), increased incidence of relapse (P = .002), higher incidence of aGVHD onset (P = .0005), and a composite end point of relapse or death (P = .0017). A Cox proportional hazards multivariate model adjusted for important covariates confirmed that low DC count is independently associated with death (hazard ratio [HR], 3.8; P = .02), time to relapse (HR, 11.6; P = .001), and aGVHD (HR, 3.3; P = .04). Sensitivity and specificity rates for low DC count in predicting death or relapse are 73% and 75%, respectively. Low numbers of circulating DCs significantly increase the risk for relapse and acute GVHD and predict death after allogeneic SCT. (Blood. 2004;103:4330-4335)
Immunoglobulin class-switch recombination in mice devoid of any Sμ tandem repeat
Authors: Khamlichi Ahmed Amine , Glaudet Florence , Oruc Zeliha , Denis Vincent , Le Bert Marc , Cogné Michel
Published: February 2004

Immunoglobulin heavy-chain class-switch recombination (CSR) occurs between highly repetitive switch sequences located upstream of the constant region genes. However, the role of these sequences remains unclear. Mutant mice were generated in which most of the Iμ-Cμ intron was deleted, including all the repeats. Late B-cell development was characterized by a severe impairment, but not a complete block, in class switching to all isotypes despite normal germ line transcription. Sequence analysis of the Iμ-Cμ intron in in vitro activated–mutant splenocytes did not reveal any significant increase in activation-induced cytidine deaminase (AID)–induced somatic mutations. Analysis of switch junctions showed that, in the absence of any Sμ repeat, the Iμ exon was readily used as a substrate for CSR. In contrast to the sequence alterations downstream of the switch junctions, very few, if any, mutations were found upstream of the junction sites. Our data suggest that the core Eμ enhancer could be the boundary for CSR-associated somatic mutations. We propose that the core Eμ enhancer plays a central role in the temporal dissociation of somatic hypermutation from class switching.
Hoxb4-deficient mice undergo normal hematopoietic development but exhibit a mild proliferation defect in hematopoietic stem cells
Authors: Brun Ann C. M. , Björnsson Jon Mar , Magnusson Mattias , Larsson Nina , Leveén Per , Ehinger Mats , Nilsson Eva , Karlsson Stefan
Published: February 2004

Enforced expression of Hoxb4 dramatically increases the regeneration of murine hematopoietic stem cells (HSCs) after transplantation and enhances the repopulation ability of human severe combined immunodeficiency (SCID) repopulating cells. Therefore, we asked what physiologic role Hoxb4 has in hematopoiesis. A novel mouse model lacking the entire Hoxb4 gene exhibits significantly reduced cellularity in spleen and bone marrow (BM) and a subtle reduction in red blood cell counts and hemoglobin values. A mild reduction was observed in the numbers of primitive progenitors and stem cells in adult BM and fetal liver, whereas lineage distribution was normal. Although the cell cycle kinetics of primitive progenitors was normal during endogenous hematopoiesis, defects in proliferative responses of BM Lin- Sca1+ c-kit+ stem and progenitor cells were observed in culture and in vivo after the transplantation of BM and fetal liver HSCs. Quantitative analysis of mRNA from fetal liver revealed that a deficiency of Hoxb4 alone changed the expression levels of several other Hox genes and of genes involved in cell cycle regulation. In summary, the deficiency of Hoxb4 leads to hypocellularity in hematopoietic organs and impaired proliferative capacity. However, Hoxb4 is not required for the generation of HSCs or the maintenance of steady state hematopoiesis.
Probiotic effects on experimental graft-versus-host disease: let them eat yogurt
Authors: Gerbitz Armin , Schultz Michael , Wilke Andrea , Linde Hans-Jörg , Schölmerich Jürgen , Andreesen Reinhard , Holler Ernst
Published: February 2004

Acute graft-versus-host disease (aGVHD) often limits feasibility and outcome of allogeneic bone marrow transplantation. Current pathophysiologic concepts of aGVHD involve conditioning regimens, donor-derived T cells, proinflammatory cytokines, and bacterial lipopolysaccharide (LPS) as a major trigger for aGVHD. LPS derives mostly from gram-negative bacteria and can enter circulation through the impaired mucosal barrier after the conditioning regimen. Probiotic microorganisms have been shown to alter the composition of the intestinal microflora and thereby mediate anti-inflammatory effects. We hypothesized that modifying the enteric flora using the probiotic microorganism Lactobacillus rhamnosus GG, would ameliorate aGVHD. Here we show that oral administration of Lactobacillus rhamnosus GG before and after transplantation results in improved survival and reduced aGVHD. Furthermore, subculturing of mesenteric lymph node tissue revealed a reduced translocation of enteric bacteria. Our findings suggest that alteration of the intestinal microflora plays an important role in the initiation of experimental aGVHD. (Blood. 2004;103:4365-4367)
The peripheral benzodiazepine receptor ligand PK11195 overcomes different resistance mechanisms to sensitize AML cells to gemtuzumab ozogamicin
Authors: Walter Roland B. , Raden Brian W. , Cronk Michelle R. , Bernstein Irwin D. , Appelbaum Frederick R. , Banker Deborah E.
Published: February 2004

The antibody-targeted therapeutic, gemtuzumab ozogamicin (GO, Mylotarg), is approved for treatment of relapsed acute myeloid leukemia (AML). We previously showed that AML blasts from GO refractory patients frequently express the drug transporters P-glycoprotein (Pgp) and/or multidrug resistance protein (MRP). We also previously reported that inhibition of drug transport by the Pgp modulator, cyclosporine A (CSA), can increase GO sensitivity in Pgp+ AML cells and that the peripheral benzodiazepine receptor ligand, PK11195, sensitizes AML cells to standard chemotherapeutics both by inhibiting Pgp-mediated efflux and by promoting mitochondrial apoptosis. We now show that PK11195 also can overcome multiple resistance mechanisms to increase GO sensitivity in AML cells, including resistance associated with expression of drug transporters and/or antiapoptotic proteins. PK11195 substantially increases GO cytotoxicity in AML cells from many different cell lines and primary patient samples, often more effectively than CSA. We also show that PK11195 is nontoxic in NOD/SCID mice and can sensitize xenografted human AML cells to GO. Since PK11195 is well tolerated in humans as a single agent, its further study as a multifunctional chemosensitizer for anti-AML therapies, including GO-based therapies, is warranted. (Blood. 2004;103:4276-4284)
Infection of mature monocyte-derived dendritic cells with human cytomegalovirus inhibits stimulation of T-cell proliferation via the release of soluble CD83
Authors: Sénéchal Brigitte , Boruchov Adam M. , Reagan John L. , Hart Derek N. J. , Young James W.
Published: February 2004

We have studied the mechanisms by which human cytomegalovirus (HCMV) infection of monocyte-derived dendritic cells (moDCs) contribute to immune suppression. Unlike infection of immature moDCs, infection of mature moDCs is not lytic and results in minimally decreased surface major histocompatibility complex (MHC) and costimulatory molecule expression. The presence of a small percentage of CMV-infected mature moDCs, or the transfer of supernatant from infected moDCs depleted of infectious virions, is nevertheless sufficient to cause marked inhibition of immunostimulation by normal uninfected moDCs. Neither viral nor human interleukin 10 (IL-10) nor transforming growth factor-β-1 (TGF-β-1) could account for this inhibition. In contrast, we show that infected mature moDCs lose surface CD83 while maintaining intracellular protein expression. Soluble CD83 accumulates in the supernatants of CMV-infected mature moDCs, and CD83 immunodepletion removes the inhibitory effect of these supernatants on normal DC immunostimulation. We have thus discovered a new mechanism by which HCMV infection may establish a nonlytic reservoir in mature moDCs that inhibits DC-mediated T-cell responses. (Blood. 2004;103:4207-4215)
Human B lymphoblastoid cells contain distinct patterns of cathepsin activity in endocytic compartments and regulate MHC class II transport in a cathepsin S-independent manner
Authors: Lautwein Alfred , Kraus Marianne , Reich Michael , Burster Timo , Brandenburg J , Overkleeft Herman S , Schwarz Gerold , Kammer Winfried , Weber Ekkehard , Kalbacher Hubert , Nordheim Alfred , Driessen Christoph
Published: February 2004

Endocytic proteolysis represents a major functional component of the major histocompatibility complex class II antigen-presentation machinery. Although transport and assembly of class II molecules in the endocytic compartment are well characterized, we lack information about the pattern of endocytic protease activity along this pathway. Here, we used chemical tools that visualize endocytic proteases in an activity-dependent manner in combination with subcellular fractionation to dissect the subcellular distribution of the major cathepsins (Cat) CatS, CatB, CatH, CatD, CatC, and CatZ as well as the asparagine-specific endoprotease (AEP) in human B-lymphoblastoid cells (BLC). Endocytic proteases were distributed in two distinct patterns: CatB and CatZ were most prominent in early and late endosomes but absent from lysosomes, and CatH, CatS, CatD, CatC, and AEP distributed between late endosomes and lysosomes, suggesting that CatB and CatZ might be involved in the initial proteolytic attack on a given antigen. The entire spectrum of protease activity colocalized with human leukocyte antigen-DM and the C-terminal and N-terminal processing of invariant chain (Ii) in late endosomes. CatS was active in all endocytic compartments. Surprisingly and in contrast with results from dendritic cells, inhibition of CatS activity by leucine–homophenylalanine–vinylsulfone-phenol prevented N-terminal processing of Ii but did not alter the subcellular trafficking or surface delivery of class II complexes, as deferred from pulse-chase analysis in combination with subcellular fractionation and biotinylation of cell-surface protein. Thus, BLC contain distinct activity patterns of proteases in endocytic compartments and regulate the intracellular transport and surface-delivery of class II in a CatS-independent manner.
Diesel exhaust particles increase LPS-stimulated COX-2 expression and PGE2 production in human monocytes
Authors: Hofer Thomas P J , Bitterle Ellen , Beck-Speier Ingrid , Maier Konrad L , Frankenberger Marion , Heyder Joachim , Ziegler-Heitbrock Löms
Published: February 2004

Little is known about health effects of ultrafine particles (UFP) found in ambient air, but much of their action may be on cells of the lung, including cells of the monocyte/macrophage lineage. We have analyzed the effects of diesel exhaust particles (DEP; SRM1650a) on human monocytes in vitro. DEP, on their own, had little effect on cyclooxygenase (COX)-2 gene expression in the Mono Mac 6 cell line. However, when cells were preincubated with DEP for 1 h, then stimulation with the Toll-like receptor 4 (TLR4) ligand lipopolysaccharide (LPS) induced an up-to fourfold-higher production of COX-2 mRNA with an average twofold increase. This costimulatory effect of DEP led to enhanced production of COX-2 protein and to increased release of prostaglandin E2 (PGE2). The effect was specific in that tumor necrosis factor gene expression was not enhanced by DEP costimulation. Furthermore, costimulation with the TLR2 ligand Pam3Cys also led to enhanced COX-2 mRNA. DEP and LPS showed similar effects on COX-2 mRNA in primary blood mononuclear cells, in highly purified CD14-positive monocytes, and in monocyte-derived macrophages. Our data suggest that UFP such as DEP may exert anti-inflammatory effects mediated by enhanced PGE2 production.
Streptococcus pyogenesandLactobacillus rhamnosusdifferentially induce maturation and production of Th1-type cytokines and chemokines in human monocyte-derived dendritic cells
Authors: Veckman Ville , Miettinen Minja , Pirhonen Jaana , Sirén Jukka , Matikainen Sampsa , Julkunen Ilkka
Published: February 2004

Dendritic cells (DCs) are the most efficient antigen-presenting cells and thus, have a major role in regulating host immune responses. In the present study, we have analyzed the ability of Gram-positie, pathogenic Streptococcus pyogenes and nonpathogenic Lactobacillus rhamnosus to induce the maturation of human monocyte-derived DCs. Stimulation of DCs with S. pyogenes resulted in strong expression of DC costimulatory molecules CD80, CD83, and CD86 accompanied with a T helper cell type 1 (Th1) cytokine and chemokine response. S. pyogenes also induced interleukin (IL)-2 and IL-12 production at mRNA and protein levels. In addition, IL-23 and IL-27 subunits p40, p19, p28, and EBI3 were induced at mRNA level. In contrast, L. rhamnosus-stimulated DCs showed only moderate expression of costimulatory molecules and produced low levels of cytokines and chemokines. Furthermore, no production of IL-2 or IL-12 family cytokines was detected. Bacteria-induced DC maturation and especially cytokine and chemokine production were reduced when bacteria were heat-inactivated. Our results show that human monocyte-derived DCs respond differently to different Gram-positive bacteria. Although pathogenic S. pyogenes induced a strong Th1-type response, stimulation with nonpathogenic L. rhamnosus resulted in development of semi-mature DCs characterized by moderate expression of costimulatory molecules and low cytokine production.
TGF-β: the perpetrator of immune suppression by regulatory T cells and suicidal T cells
Authors: Wahl Sharon M , Swisher Jennifer , McCartney-Francis Nancy , Chen Wanjun
Published: February 2004

Innate and adaptive immunity function to eliminate foreign invaders and respond to injury while enabling coexistence with commensal microbes and tolerance against self and innocuous agents. Although most often effective in accomplishing these objectives, immunologic processes are not fail-safe and may underserve or be excessive in protecting the host. Checks and balances to maintain control of the immune system are in place and are becoming increasingly appreciated as targets for manipulating immunopathologic responses. One of the most recognized mediators of immune regulation is the cytokine transforming growth factor-β (TGF-β), a product of immune and nonimmune cells. Emerging data have unveiled a pivotal role for TGF-β as a perpetrator of suppression by CD4+CD25+ regulatory T (Treg) cells and in apoptotic sequelae. Through its immunosuppressive prowess, TGF-β effectively orchestrates resolution of inflammation and control of autoaggressive immune reactions by managing T cell anergy, defining unique populations of Treg cells, regulating T cell death, and influencing the host response to infections.
Annexin 1 and the biology of the neutrophil
Authors: Perretti Mauro , Flower Roderick John
Published: February 2004

This overview will focus on one aspect of neutrophil biology, which is the selective activation of the annexin 1 system in relation to the process of cell extravasation. Besides the current view about the biochemistry of annexin 1 and annexin 1 receptor(s) up-regulation within the microenvironment of the adherent neutrophils, we will also comment on the final result achieved by activation of the system, which is inhibition of neutrophil recruitment. In view of the historical link between annexin 1 and glucocorticoids, the potential for the annexin 1 system in mediating at least some of the anti-inflammatory actions of these powerful drugs is also discussed.
Cannabinoid receptor-mediated regulation of intracellular calcium by Δ9-tetrahydrocannabinol in resting T cells
Authors: Rao Gautham K , Zhang Wei , Kaminski Norbert E
Published: February 2004

Cannabinoids exhibit broad immune modulating activity by targeting many cell types within the immune system, including T cells, which exhibit sensitivity, as evidenced by altered activation, proliferation, and cytokine expression. As a result of the critical role calcium plays in T cell function coupled with previous findings demonstrating disruption of the calcium-regulated transcription factor, nuclear factor of activated T cells, by cannabinoid treatment the objective of the present investigation was to perform an initial characterization of the role of the cannabinoid receptors in the regulation of the intracellular calcium concentration ([Ca2+]i) by Δ9-tetrahydrocannabinol (Δ9-THC) in T lymphocytes. Here, we demonstrate that Δ9-THC robustly elevates [Ca2+]i in purified murine splenic T cells and in the human peripheral blood acute lymphoid leukemia (HPB-ALL) human T cell line but only minimally elevates [Ca2+]i in Jurkat E6-1 (dysfunctional cannabinoid receptor 2-expressing) human T cells. Removal of extracellular calcium severely attenuated the Δ9-THC-mediated rise in [Ca2+]i in murine splenic T cells and HPB-ALL cells. Pretreatment with cannabinoid receptor antagonists, SR144528 and/or SR141716A, led to an attenuation of Δ9-THC-mediated elevation in [Ca2+]i in splenic T cells and HPB-ALL cells but not in Jurkat E6-1 cells. Furthermore, pretreatment of HPB-ALL cells with SR144528 antagonized the small rise in [Ca2+]i elicited by Δ9-THC in the absence of extracellular calcium. These findings suggest that Δ9-THC induces an influx of extracellular calcium in resting T cells in a cannabinoid receptor-dependent manner.
In Vitro Increase in Intracellular Calcium Concentrations Induced by Low or High Extracellular Glucose Levels in Ependymocytes and Serotonergic Neurons of the Rat Lower Brainstem
Authors: Moriyama Ryutaro , Tsukamura Hiroko , Kinoshita Mika , Okazaki Hirokatsu , Kato Yukio , Maeda Kei-ichiro
Published: February 2004

Pancreatic glucokinase (GK)-like immunoreactivities are located in ependymocytes and serotonergic neurons of the rat brain. The present study investigated in vitro changes in intracellular calcium concentrations ([Ca2+]i) in response to low (2 mm) or high (20 mm) extracellular glucose concentrations in isolated cells from the wall of the central canal (CC), raphe obscurus nucleus (ROb), ventromedial hypothalamus (VMH), and lateral hypothalamic area (LHA) in male rats. An increase in [Ca2+]i was found in cells from the CC (21.1% or 9.8% of ependymocytes), ROb (10.9% or 14.5% of serotonergic neurons), VMH (7.8% and 25.2% of neurons), and LHA (20% or 15.7% of neurons), when extracellular glucose levels were changed from 10 to either 2 or 20 mm, respectively. Most of the ependymocytes and serotonergic neurons responding to the glucose changes were immunoreactive to the anti-GK in the CC (96.8% for low glucose and 100% for high glucose) and ROb (100% for low and high glucose). The [Ca2+]i increase was blocked with calcium-free medium or L-type calcium channel blocker. Cells with an increase in [Ca2+]i in response to low glucose did not respond to high glucose and vice versa. Inhibition of GK activity with acute alloxan treatment blocked low or high glucose-induced [Ca2+]i increases in most GK-immunoreactive cells from the CC or ROb. The glucose-sensitive [Ca2+]i increase in neurons of the VMH and LHA was also alloxan-sensitive, but no cells taken from the VMH and LHA were immunoreactive to the antibody used. The present study further indicates that ependymocytes of the CC and serotonergic neurons in the ROb are also sensitive to the changes in extracellular glucose in a GK-dependent manner, but that the subtype of GK in these cells could be different from that in the VMH and LHA.
Characterization of the Interactions of Estrogen Receptor and MNAR in the Activation of cSrc
Authors: Barletta Frank , Wong Chi-Wai , McNally Chris , Komm Barry S. , Katzenellenbogen Benita , Cheskis Boris J.
Published: February 2004

In this study, we have evaluated the molecular mechanism of Src activation after its interaction with estrogen receptor α (ERα) and a newly identified scaffold protein, called MNAR (modulator of nongenomic activity of ER). Under basal condition, Src enzymatic activity is inhibited by intramolecular interactions. The enzyme can be activated by interaction between the SH2 domain of Src and phosphotyrosine-containing sequences and/or by interaction between the SH3 domain of Src and proteins containing PXXP motifs. Mutational analysis and functional evaluation of MNAR and the use of ERα and cSrc mutants revealed that MNAR interacts with Src’s SH3 domain via its N-terminal PXXP motif. Mutation of this motif abolished both the MNAR-induced activation of Src and the stimulation of ER transcriptional activity. ER interacts with Src’s SH2 domain using phosphotyrosine 537, and this complex was further stabilized by MNAR-ER interaction. Mapping studies reveal that both the A/B domain and Y537 of ERα are required for MNAR-induced activation of ER transcriptional activity. The region responsible for MNAR interaction with ER maps to two N-terminal LXXLL motifs of MNAR. Mutation of these motifs prevented ER-MNAR complex formation and eliminated activation of the Src/MAPK pathway. These data explicate how the coordinate interactions between MNAR, ER, and Src lead to Src activation. Our findings also demonstrate that MNAR is a scaffold protein that mediates ER-Src interaction and plays an important role in the integration of ER action in Src-mediated signaling.
Overlapping mechanisms function to establish transcriptional quiescence in the embryonicDrosophilagermline
Authors: Deshpande Girish , Calhoun Gretchen , Schedl Paul
Published: February 2004

In Drosophila melanogaster, the germline precursor cells, i.e. pole cells, are formed at the posterior of the embryo. As observed for newly formed germ cells in many other eukaryotes, the pole cells are distinguished from the soma by their transcriptional quiescence. To learn more about the mechanisms involved in establishing quiescence, we ectopically expressed a potent transcriptional activator, Bicoid (Bcd), in pole cells. We find that Bcd overrides the machinery that downregulates transcription, and activates not only its target gene hunchback but also the normally female specific Sex-lethal promoter, Sxl-Pe, in the pole cells of both sexes. Unexpectedly, the terminal pathway gene torso-like is required for Bcd-dependent transcription. However, terminal signaling is known to be attenuated in pole cells, and this raises the question of how this is accomplished. We present evidence indicating that polar granule component (pgc) is required to downregulate terminal signaling in early pole cells. Consistently, pole cells compromised for pgc function exhibit elevated levels of activated MAP kinase and premature transcription of the target gene tailless (tll). Furthermore, pgc is required to establish a repressive chromatin architecture in pole cells.
Cooperation between sonic hedgehog and fibroblast growth factor/MAPK signalling pathways in neocortical precursors
Authors: Kessaris Nicoletta , Jamen Françoise , Rubin Lee L. , Richardson William D.
Published: February 2004

Sonic hedgehog (SHH) and fibroblast growth factor 2 (FGF2) can both induce neocortical precursors to express the transcription factor OLIG2 and generate oligodendrocyte progenitors (OLPs) in culture. The activity of FGF2 is unaffected by cyclopamine, which blocks Hedgehog signalling, demonstrating that the FGF pathway to OLP production is Hedgehog independent. Unexpectedly,SHH-mediated OLP induction is blocked by PD173074, a selective inhibitor of FGF receptor (FGFR) tyrosine kinase. SHH activity also depends on mitogen-activated protein kinase (MAPK) but SHH does not itself activate MAPK. Instead, constitutive activity of FGFR maintains a basal level of phosphorylated MAPK that is absolutely required for the OLIG2- and OLP-inducing activities of SHH. Stimulating the MAPK pathway with a retrovirus encoding constitutively active RAS shows that the requirement for MAPK is cell-autonomous, i.e. MAPK is needed together with SHH signalling in the cells that become OLPs.
Contribution of Hox genes to the diversity of the hindbrain sensory system
Authors: Gaufo Gary O. , Wu Sen , Capecchi Mario R.
Published: February 2004

The perception of environmental stimuli is mediated through a diverse group of first-order sensory relay interneurons located in stereotypic positions along the dorsoventral (DV) axis of the neural tube. These interneurons form contiguous columns along the anteroposterior (AP) axis. Like neural crest cells and motoneurons, first-order sensory relay interneurons also require specification along the AP axis. Hox genes are prime candidates for providing this information. In support of this hypothesis, we show that distinct combinations of Hox genes in rhombomeres (r) 4 and 5 of the hindbrain are required for the generation of precursors for visceral sensory interneurons. As Hoxa2 is the only Hox gene expressed in the anterior hindbrain(r2), disruption of this gene allowed us to also demonstrate that the precursors for somatic sensory interneurons are under the control of Hox genes. Surprisingly, the Hox genes examined are not required for the generation of proprioceptive sensory interneurons. Furthermore, the persistence of some normal rhombomere characteristics in Hox mutant embryos suggests that the loss of visceral and somatic sensory interneurons cannot be explained solely by changes in rhombomere identity. Hox genes may thus directly regulate the specification of distinct first-order sensory relay interneurons within individual rhombomeres. More generally, these findings contribute to our understanding of how Hox genes specifically control cellular diversity in the developing organism
Specification of vertebral identity is coupled to Notch signalling and the segmentation clock
Authors: Cordes Ralf , Schuster-Gossler Karin , Serth Katrin , Gossler Achim
Published: February 2004

To further analyse requirements for Notch signalling in patterning the paraxial mesoderm, we generated transgenic mice that express in the paraxial mesoderm a dominant-negative version of Delta1. Transgenic mice with reduced Notch activity in the presomitic mesoderm as indicated by loss of Hes5 expression were viable and displayed defects in somites and vertebrae consistent with known roles of Notch signalling in somite compartmentalisation. In addition, these mice showed with variable expressivity and penetrance alterations of vertebral identities resembling homeotic transformations, and subtle changes of Hox gene expression in day 12.5 embryos. Mice that carried only one functional copy of the endogenous Delta1 gene also showed changes of vertebral identities in the lower cervical region, suggesting a previously unnoticed haploinsufficiency for Delta1. Likewise, in mice carrying a null allele of the oscillating Lfng gene, or in transgenic mice expressing Lfngconstitutively in the presomitic mesoderm, vertebral identities were changed and numbers of segments in the cervical and thoracic regions were reduced,suggesting anterior shifts of axial identity. Together, these results provide genetic evidence that precisely regulated levels of Notch activity as well as cyclic Lfng activity are critical for positional specification of the anteroposterior body axis in the paraxial mesoderm.
Roles for p53 and p73 during oligodendrocyte development
Authors: Billon Nathalie , Terrinoni Alessandro , Jolicoeur Christine , McCarthy Afshan , Richardson William D. , Melino Gerry , Raff Martin
Published: February 2004

Oligodendrocytes make myelin in the vertebrate central nervous system(CNS). They develop from oligodendrocyte precursor cells (OPCs), most of which divide a limited number of times before they stop and differentiate. OPCs can be purified from the developing rat optic nerve and stimulated to proliferate in serum-free culture by PDGF. They can be induced to differentiate in vitro by either thyroid hormone (TH) or PDGF withdrawal. It was shown previously that a dominant-negative form of p53 could inhibit OPC differentiation induced by TH but not by PDGF withdrawal, suggesting that the p53 family of proteins might play a part in TH-induced differentiation. As the dominant-negative p53 used inhibited all three known p53 family members - p53, p63 and p73 - it was uncertain which family members are important for this process. Here, we provide evidence that both p53 and p73, but not p63, are involved in TH-induced OPC differentiation and that p73 also plays a crucial part in PDGF-withdrawal-induced differentiation. This is the first evidence for a role of p73 in the differentiation of a normal mammalian cell.
Laser milling as a ‘rapid’ micromanufacturing process
Authors: Pham D T , Dimov S S , Ji C , Petkov P V , Dobrev T
Published: February 2004

Laser milling involves applying laser energy to remove material through ablation in a layer-by-layer fashion. Computer numerical control (CNC) programs for laser milling are obtained directly from a three-dimensional computer aided design (CAD) model of the workpiece. Thus, apart from being a material removal rather than a material accretion system, a laser milling machine operates like any other layered manufacturing technology equipment. This paper reviews the physical phenomena underlying the interaction between a laser beam and a workpiece and the mechanisms governing the ablation process with a view to identifying the key process parameters. The paper then focuses on the use of laser milling to manufacture small parts rapidly in materials that are difficult to machine by conventional means.
The superficial layer of parts machined by brush electro-discharge mechanical machining (BEDMM)
Authors: Nowicki B , Pierzynowski R , Spadło S
Published: February 2004

The paper presents a brief study of brush electro-discharge mechanical machining (BEDMM) with an elastic, discrete electrode. This method is useful for the smoothing of free-form surfaces using a general-use electrode. It can be realized as a combination of mechanical and erosion machining or it can be effected with the same tool as an additional operation of mechanical machining that would result with additional smoothing and introduction of the compression stress into the surface layer. The surface layer created after BEDMM is featured with a considerable share of the cathode material and the obtained roughness Ra is approximately 1 μm.