bluuebunny/crossref_metadata_2025 huggingface dataset:
Activating Mutation of the Renal Epithelial Chloride Channel ClC-Kb Predisposing to Hypertension
Authors: Jeck Nikola , Waldegger Siegfried , Lampert Angelika , Boehmer Christoph , Waldegger Petra , Lang Philipp A. , Wissinger Bernd , Friedrich Björn , Risler Teut , Moehle Robert , Lang Undine E. , Zill Peter , Bondy Brigitta , Schaeffeler Elke , Asante-Poku Stephen , Seyberth Hannsjörg , Schwab Matthias , Lang Florian
Published: May 2004

The chloride channel ClC-Kb is expressed in the basolateral cell membrane of the distal nephron and participates in renal NaCl reabsorption. Loss-of-function mutations of ClC-Kb lead to classic Bartter syndrome, a rare salt-wasting disorder. Recently, we identified the ClC-Kb
T481S
polymorphism, which confers a strong gain-of-function effect on the ClC-Kb chloride channel. The present study has been performed to explore the prevalence of the mutation and its functional significance in renal salt handling and blood pressure regulation. As evident from electrophysiological analysis with the 2-electrode voltage-clamp technique, heterologous expression of ClC-Kb
T481S
in Xenopus oocytes gave rise to a current that was 7-fold larger than the current produced by wild-type ClC-Kb. The prevalence of the mutant allele was significantly higher in an African population from Ghana (22%) than in whites (12%). As tested in 1 white population, carriers of ClC-Kb
T481S
were associated with significantly higher systolic (by ≈6.0 mm Hg) and diastolic (by ≈4.2 mm Hg) blood pressures and significantly higher prevalence (45% versus 25%) of hypertensive (≥140/90 mm Hg) blood pressure levels. Individuals carrying ClC-Kb
T481S
had significantly higher plasma Na
+
concentrations and significantly decreased glomerular filtration rate. In conclusion, the mutation ClC-Kb
T481S
of the renal epithelial Cl
−
channel ClC-Kb strongly activates ClC-Kb chloride channel function in vitro and may predispose to the development of essential hypertension in vivo.
Platelet 12-Lipoxygenase Activation via Glycoprotein VI
Authors: Coffey Marcus J. , Jarvis Gavin E. , Gibbins Jonathan M. , Coles Barbara , Barrett Natasha E. , Wylie Oliver R.E. , O’Donnell Valerie B.
Published: May 2004

Lipoxygenases (LOX) contribute to vascular disease and inflammation through generation of bioactive lipids, including 12-hydro(pero)xyeicosatetraenoic acid (12-H(P)ETE). The physiological mechanisms that acutely control LOX product generation in mammalian cells are uncharacterized. Human platelets that contain a 12-LOX isoform (p12-LOX) were used to define pathways that activate H(P)ETE synthesis in the vasculature. Collagen and collagen-related peptide (CRP) (1 to 10 μg/mL) acutely induced platelet 12-H(P)ETE synthesis. This implicated the collagen receptor glycoprotein VI (GPVI), which signals via the immunoreceptor-based activatory motif (ITAM)-containing FcRγ chain. Conversely, thrombin only activated at high concentrations (> 0.2 U/mL), whereas U46619 and ADP alone were ineffective. Collagen or CRP-stimulated 12-H(P)ETE generation was inhibited by staurosporine, PP2, wortmannin, BAPTA/AM, EGTA, and L-655238, implicating
src
-tyrosine kinases, PI3-kinase, Ca
2+
mobilization, and p12-LOX translocation. In contrast, protein kinase C (PKC) inhibition potentiated 12-H(P)ETE generation. Finally, activation of the immunoreceptor tyrosine-based inhibitory motif (ITIM)–containing platelet endothelial cell adhesion molecule (PECAM-1) inhibited p12-LOX product generation. This study characterizes a receptor-dependent pathway for 12-H(P)ETE synthesis via the collagen receptor GPVI, which is negatively regulated by PECAM-1 and PKC, and demonstrates a novel link between immune receptor signaling and lipid mediator generation in the vasculature.
Angiotensin II AT
1
Receptor Blockade Reverses Pathological Hypertrophy and Inflammation in Brain Microvessels of Spontaneously Hypertensive Rats
Authors: Ando Hiromichi , Zhou Jin , Macova Miroslava , Imboden Hans , Saavedra Juan M.
Published: May 2004

Background and Purpose—

The spontaneously hypertensive rat (SHR) is vulnerable to brain ischemia and stress and exhibits a chronically stimulated brain angiotensin II system, cerebrovascular hypertrophy, and inflammation. Pretreatment with angiotensin II type 1 (AT
1
) receptor antagonists protects from brain ischemia and from stress and prevents the development of stress-induced gastric ulcers in part by reducing inflammation in the gastric mucosa. We studied whether AT
1
receptor antagonists could exert antiinflammatory effects in the brain vasculature as a mechanism for their protective effects against ischemia.

Methods—

Ten-week-old SHR and normotensive Wistar-Kyoto male rats received the AT
1
receptor antagonist candesartan (0.3 mg/kg per day) or vehicle for 28 days via osmotic minipumps. We studied AT
1
receptors, intercellular adhesion molecule-1 (ICAM-1), endothelial nitric oxide synthase (eNOS), and number of macrophages by immunohistochemistry and Western blots.

Results—

We found increased endothelial AT
1
receptor expression of brain microvessels and middle cerebral artery of SHR. Brain AT
1
receptor inhibition reversed the pathological vascular hypertrophy, increased and normalized eNOS expression, and decreased ICAM-1 expression and the number of adherent and infiltrating macrophages in cerebral vessels of SHR.

Conclusions—

The antiinflammatory effects of AT
1
receptor antagonists may be an important mechanism in protecting against ischemia.
Increased Arterial Stiffness Is Independently Related to Cerebrovascular Disease and Aneurysms of the Abdominal Aorta
Authors: Dijk J.M. , van der Graaf Y. , Grobbee D.E. , Banga J.D. , Bots M.L.
Published: May 2004

Background—

Arterial stiffness is a risk factor for stroke and myocardial infarction. We investigated whether carotid arterial stiffness is related to other localizations of manifest arterial disease.

Methods—

Carotid artery stiffness was measured by ultrasonography as the change in diameter in systole relative to the diastolic diameter in patients enrolled in the Second Manifestations of Arterial Disease (SMART) Study, a cohort study among patients with manifest cardiovascular disease or cardiovascular risk factors. The first consecutive 1561 patients with manifest cardiovascular disease were classified in 4 categories: cerebrovascular disease, coronary artery disease, peripheral artery disease, or aneurysm of the abdominal aorta (AAA). Differences in arterial stiffness among the categories were studied by linear regression analyses. Patients with coronary artery disease as single diagnosis (n=482) served as reference group.

Results—

Patients with cerebrovascular disease (arterial distension −42.0 μm [95% CI, −57.2 to −26.8]) and those with an AAA (−64.4 μm [95% CI, −84.8 to −44.0]) had an increased carotid stiffness compared with the reference group. Adjustment for confounders attenuated the relations, which remained statistically significant (−34.2 μm [95% CI, −47.8 to −20.7] and −33.2 μm [95% CI, −51.8 to −14.6], respectively).

Conclusion—

Our study suggests that increased arterial stiffness is important in the pathophysiology of especially cerebrovascular disease and AAA. That the differences in arterial stiffness between disease categories attenuated after adjustment for important risk factors but remained significant suggests that besides being an element in the causal pathway, arterial stiffness is also a risk factor for cardiovascular disease itself.
Erythropoietin gene from a teleost fish, Fugu rubripes
Authors: Chou Chih-Fong , Tohari Sumanty , Brenner Sydney , Venkatesh Byrappa
Published: May 2004

In this paper we report the cloning and characterization of the erythropoietin (Epo) gene from the pufferfish, Fugu rubripes. This is the first nonmammalian Epo gene to be cloned. The Fugu Epo comprises 5 exons and 4 introns similar to the human EPO, and encodes a 185–amino acid protein that is 32% to 34% identical to Epo from various mammals. The synteny of genes at the Epo locus is conserved between the Fugu and humans. Unlike in mammals in which adult kidney is the primary Epo-producing organ, the heart is the main Epo-producing organ in adult Fugu. In addition to the heart, Fugu Epo is also expressed in the liver and brain similar to the human EPO. Interestingly, the transcripts in the Fugu brain are generated from a distal promoter and include an alternatively spliced first coding exon. No such brain-specific alternative splicing of Epo has been reported in mammals so far. Transient transfection studies in a fish hepatoma cell line (PLHC-1) and a human hepatoma cell line (HepG2) suggest that although the Fugu Epo promoter many not be hypoxia inducible, the gene may be regulated by hypoxia.
Apoptotic resistance to ionizing radiation in pediatric B-precursor acute lymphoblastic leukemia frequently involves increased NF-κB survival pathway signaling
Authors: Weston Victoria J. , Austen Belinda , Wei Wenbin , Marston Eliot , Alvi Azra , Lawson Sarah , Darbyshire Philip J. , Griffiths Mike , Hill Frank , Mann Jill R. , Moss Paul A. H. , Taylor A. Malcolm R. , Stankovic Tatjana
Published: May 2004

To investigate possible causes of the variable response to treatment in pediatric B-precursor acute lymphoblastic leukemia (ALL) and to establish potential novel therapeutic targets, we used ionizing radiation (IR) exposure as a model of DNA damage formation to identify tumors with resistance to p53-dependent apoptosis. Twenty-one of 40 ALL tumors responded normally to IR, exhibiting accumulation of p53 and p21 proteins and cleavage of caspases 3, 7, and 9 and of PARP1. Nineteen tumors exhibited apoptotic resistance and lacked PARP1 and caspase cleavage; although 15 of these tumors had normal accumulation of p53 and p21 proteins, examples exhibited abnormal expression of TRAF5, TRAF6, and cIAP1 after IR, suggesting increased NF-κB prosurvival signaling as the mechanism of apoptotic resistance. The presence of a hyperactive PARP1 mutation in one tumor was consistent with such increased NF-κB activity. PARP1 inhibition restored p53-dependent apoptosis after IR in these leukemias by reducing NF-κB DNA binding and transcriptional activity. In the remaining 4 ALL tumors, apoptotic resistance was associated with a TP53 mutation or with defective activation of p53. We conclude that increased NF-κB prosurvival signaling is a frequent mechanism by which B-precursor ALL tumors develop apoptotic resistance to IR and that PARP1 inhibition may improve the DNA damage response of these leukemias.
Effects of lethal irradiation in zebrafish and rescue by hematopoietic cell transplantation
Authors: Traver David , Winzeler Alissa , Stern Howard M. , Mayhall Elizabeth A. , Langenau David M. , Kutok Jeffrey L. , Look A. Thomas , Zon Leonard I.
Published: May 2004

The study of hematopoiesis has been greatly facilitated by transplantation of blood cell populations into recipient animals. Efficient engraftment of donor cells generally requires ablation of the host hematopoietic system. The zebrafish has recently emerged as a developmental and genetic system to study hematopoiesis. To enable the study of hematopoietic stem cell (HSC) biology, immune cell function, and leukemogenesis in zebrafish, we have developed hematopoietic cell transplantation (HCT) into adult recipient animals conditioned by γ irradiation. Dose-response experiments showed that the minimum lethal dose (MLD) of 40 Gy led to the specific ablation of hematolymphoid cells and death by 14 days after irradiation. Sublethal irradiation doses of 20 Gy predominantly ablated lymphocytes and permitted transplantation of a lethal T-cell leukemia. Finally, transplantation of hematopoietic cells carrying transgenes yielding red fluorescent erythrocytes and green fluorescent leukocytes showed that HCT is sufficient to rescue the MLD, that recipient hematolymphoid tissues were repopulated by donor-derived cells, and that donor blood cell lineages can be independently visualized in living recipients. Together, these results establish transplantation assays to test for HSC function and oncogenic transformation in zebrafish.
Anti-α4 integrin antibody suppresses the development of multiple myeloma and associated osteoclastic osteolysis
Authors: Mori Yoshihisa , Shimizu Nobuaki , Dallas Mark , Niewolna Maryla , Story Beryl , Williams Paul J. , Mundy Gregory R. , Yoneda Toshiyuki
Published: May 2004

Supporting roles of stromal cells in preferential colonization of myeloma cells in bone marrow and development of associated osteoclastic osteolysis through cell-cell interactions have been indicated. Here we examined the effects of a monoclonal antibody to α4 integrin (anti-α4 Ab) that disrupts myeloma cell-stromal cell interactions mediated via α4β1 integrin and vascular cell adhesion molecule-1 (VCAM-1) on myeloma cell growth in bone marrow and accompanying osteolysis. The anti-α4 Ab decreased VCAM-1-stimulated 5TGM1/luc cell growth in culture. The 5TGM1 murine myeloma cells stably transfected with the firefly luciferase (5TGM1/luc) were inoculated from tail vein in bg/xid/nd mice. Preventative administration of the anti-α4 Ab suppressed the elevation of serum IgG2b levels, decreased 5TGM1/luc tumor burden with increased apoptosis in bone and spleen, reduced bone destruction with diminished number of osteoclasts, and prolonged survival of 5TGM1/luc-bearing mice. In contrast, therapeutic administration of the antibody failed to show these effects. However, therapeutic administration of the antibody combined with melphalan significantly suppressed serum IgG2b levels and tumor burden in bone. Our results suggest that the interactions with stromal cells via α4β1/VCAM-1 are critical to the development of myeloma and associated osteolysis and that disruption of these interactions using anti-α4 Ab is a potential therapeutic approach for myeloma. (Blood. 2004;104:2149-2154)
Mutations of AML1 are common in therapy-related myelodysplasia following therapy with alkylating agents and are significantly associated with deletion or loss of chromosome arm 7q and with subsequent leukemic transformation
Authors: Christiansen Debes H. , Andersen Mette K. , Pedersen-Bjergaard Jens
Published: May 2004

The AML1 transcription factor is essential for normal hematopoiesis and is the target of several chromosomal translocations in acute leukemia. Acquired somatic AML1 mutations were recently demonstrated sporadically in de novo myelodysplasia (MDS) and acute myeloid leukemia (AML) including a few cases of therapy-related disease (t-MDS/t-AML). We examined 140 patients with t-MDS or t-AML for AML1 mutations by direct sequencing. We identified 9 missense, 3 nonsense, and 10 frameshift mutations, all heterozygous, in 22 patients (15.7%). Thirteen mutations were located in the N-terminal Runt homology domain (RHD), whereas 9 mutations were located in the C-terminal region including the transactivation domain (TAD). Nineteen patients with AML1 mutations had previously received alkylating agents whereas 2 patients had received radiotherapy only. AML1 mutations were highly significantly associated with presentation of the disease as t-MDS (P = .003), with deletion or loss of chromosome arm 7q (P = .001) and with subsequent transformation to overt t-AML (P = .0001). Patients with missense mutations presented a shorter survival compared with patients with nonsense/frameshift mutations (P = .03). Our results suggest that AML1 mutations and deletion of genes on chromosome arm 7q cooperate in leukemogenesis and predispose to leukemic transformation.
Platelet surface glutathione reductase-like activity
Authors: Essex David W. , Li Mengru , Feinman Richard D. , Miller Anna
Published: May 2004

We previously found that reduced glutathione (GSH) or a mixture of GSH/glutathione disulfide (GSSG) potentiated platelet aggregation. We here report that GSSG, when added to platelets alone, also potentiates platelet aggregation. Most of the GSSG was converted to GSH by a flavoprotein-dependent platelet surface mechanism. This provided an appropriate redox potential for platelet activation. The addition of GSSG to platelets generated sulfhydryls in the β subunit of the αIIbβ3 fibrinogen receptor, suggesting a mechanism for facilitation of agonist-induced platelet activation.
Prevalence and incidence of severe sepsis in Dutch intensive care units
Authors: van Gestel Aukje , Bakker Jan , Veraart Christiaan PWM , van Hout Ben A
Published: May 2004

Introduction

Severe sepsis is a dreaded consequence of infection and necessitates intensive care treatment. Severe sepsis has a profound impact on mortality and on hospital costs, but recent incidence data from The Netherlands are not available. The purpose of the present study was to determine the prevalence and incidence of severe sepsis occurring during the first 24 hours of admission in Dutch intensive care units (ICUs).

Methods

Forty-seven ICUs in The Netherlands participated in a point prevalence survey and included patients with infection at the time of ICU admission. Clinical symptoms of severe sepsis during the first 24 hours of each patient's ICU stay were recorded and the prevalence of severe sepsis was calculated. Then, the annual incidence of severe sepsis in The Netherlands was estimated, based on the prevalence, the estimated length of stay, and the capacity of the participating ICUs relative to the national intensive care capacity.

Results

The participating ICUs had 442 beds available for admissions, which was estimated to be 42% of the national ICU capacity. At the time of the survey, 455 patients were currently admitted and 151 were included in the analysis; 134 (29.5%) patients met criteria for severe sepsis. The most common failing organ system was the respiratory system (90%), and most patients were admitted following surgery (37%) and were admitted because of acute infection (62%). The most prevalent source of infection was the lung (47%). The estimated duration of ICU stay for severe sepsis patients was 13.3 ± 1.1 days.

Conclusion

The annual number of admissions for severe sepsis in Dutch ICUs was calculated at 8643 ± 929 cases/year, which is 0.054% of the population, 0.61% of hospital admissions and 11% of ICU admissions.
Epidemiology of sepsis in Norway in 1999
Authors: Flaatten Hans
Published: May 2004

Introduction

Sepsis and severe sepsis are asociated with high hospital mortality. Little is known about the occurrence of sepsis in general hospital populations. The goal of the present study was to reveal the epidemiology of sepsis in Norwegian hospitals over 1 year.

Methods

Patients admitted to all Norwegian hospitals during 1999 (n = 700,107) were analyzed by searching the database of the Norwegian Patient Registry for markers of sepsis, using International Classification of Diseases (ICD)-10 codes for sepsis and severe infections. In patients with such diagnoses, demographic data, hospital outcome data and ICD-10 codes for organ dysfunction were also retrieved. Sepsis was further classified as primary or secondary, and severe (sepsis with vital organ dysfunction) or nonsevere. The age-adjusted mortality rate, and the sepsis rates for all hospital admissions and in the Norwegian population were calculated.

Results

A total of 6665 patients were classified as having sepsis, and of these 2121 (31.8%) had severe sepsis. The most frequent failing organ system was the circulatory system, and 1562 had septic shock. Mortality increased from 7.1% (in those with no documented organ dysfunction) to 71.8% (in those with three or more organ dysfunctions). The mean mortality was 13.5%, and the mortality of severe sepsis was 27%. The incidence of sepsis was 9.5/1000 hospital admissions and 1.49/1000 inhabitants in 1999.

Conclusion

Sepsis is not uncommon in Norwegian hospitals and is associated with high hospital mortality, which is similar to recent findings from the USA. Awareness of sepsis and its appropriate treatment is mandatory in Norway if we are to reduce mortality from sepsis by 25% in the next 5 years.
Tumor Necrosis Factor α Stimulates MUC1 Synthesis and Ectodomain Release in a Human Uterine Epithelial Cell Line
Authors: Thathiah Amantha , Brayman Melissa , Dharmaraj Neeraja , Julian JoAnne J. , Lagow Errin L. , Carson Daniel D.
Published: May 2004

Regulation of MUC1 expression and removal is a salient feature of embryo implantation, bacterial clearance, and tumor progression. In some species, embryo implantation is accompanied by a transcriptional decline in uterine epithelial expression of MUC1. In other species, MUC1 is locally removed at blastocyst attachment sites, suggesting a proteolytic activity. Previously, we demonstrated that MUC1 is proteolytically released from the surface of a human uterine epithelial cell line, HES, and identified TNFα converting enzyme/a disintegrin and metalloprotease 17 as a constitutive and phorbol ester-stimulated MUC1 sheddase. The aims of the current study were to test the ability of soluble factors elevated during the periimplantation interval in vivo to stimulate ectodomain shedding of MUC1 from HES uterine epithelial cells and to characterize the nature of this proteolytic activity(ies). We identified TNFα as a prospective endogenous stimulus of MUC1 ectodomain release and of MUC1 and TNFα converting enzyme/a disintegrin and metalloprotease 17 expression. Moreover, we established that TNFα-stimulated MUC1 shedding occurs independently of increased de novo protein synthesis and demonstrated that the TNFα-induced increase in MUC1 gene expression is mediated through the κB site in the MUC1 promoter. Finally, we determined that the TNFα-sensitive MUC1 sheddase is inhibited by the metalloprotease inhibitor, TNFα protease inhibitor (TAPI), and the endogenous tissue inhibitor of metalloprotease-3. Collectively, these studies provide the initial in vitro characterization of a putative physiological stimulus of MUC1 ectodomain release and establish the nature of the metalloproteolytic activity(ies) involved.
17β-Estradiol Inhibits Class II Major Histocompatibility Complex (MHC) Expression: Influence on Histone Modifications and CBP Recruitment to the Class II MHC Promoter
Authors: Adamski Jill , Ma Zhendong , Nozell Susan , Benveniste Etty N.
Published: May 2004

Major histocompatibility complex (MHC) class II proteins are important for the initiation of immune responses and are essential for specific recognition of foreign antigens by the immune system. Regulation of class II MHC expression primarily occurs at the transcriptional level. The class II transactivator protein is the master regulator that is essential for both constitutive and interferon-γ-inducible class II MHC expression. Estrogen [17β-estradiol (17β-E2)] has been shown to have immunomodulatory effects. In this study, we show that 17β-E2 down-regulates interferon-γ inducible class II MHC protein levels on brain endothelial cells, as well as other cell types (astrocytes, fibrosacroma cells, macrophages). The inhibitory effects of 17β-E2 on class II MHC expression are not due to changes in class II transactivator mRNA or protein levels, rather, 17β-E2 mediates inhibition at the level of class II MHC gene expression. We demonstrate that 17β-E2 attenuates H3 and H4 histone acetylation and cAMP response element binding protein-binding protein association with the class II MHC promoter, suggesting that 17β-E2 inhibits class II MHC expression by a novel mechanism involving modification of the histone acetylation status of the class II MHC promoter.
A broad competence to respond to SHORT ROOT revealed by tissue-specific ectopic expression
Authors: Sena Giovanni , Jung Jee W. , Benfey Philip N.
Published: May 2004

In plants, cell fate specification depends primarily on position rather than lineage. Recent results indicate that positional information can be transmitted through intercellular trafficking of transcription factors. The SHORT ROOT (SHR) gene, a member of the GRAS family of putative transcription factors, is involved in root radial patterning in Arabidopsis. Correct radial patterning depends on the positional information transmitted through limited SHR intercellular movement and translated into cell division and specification by competent target cells. To investigate the regulation of SHR movement and the competence to respond to it, we drove expression of a translational fusion SHR::GFP using four different tissue-specific promoters. In a wild-type background, SHR::GFP was not able to move from either phloem companion cells or epidermal cells, both of which have been shown to support movement of other proteins, suggesting a requirement for tissue-specific factors for SHR movement. When expressed from its native promoter in plants with multiple endodermal layers, SHR::GFP was not able to move beyond the first endodermal layer, indicating that movement is not limited by a mechanism that recognizes boundaries between cell types. Surprisingly, movement of SHR::GFP was observed when ectopic expression from an epidermal promoter was placed in a scarecrow (scr) mutant background, revealing a possible role for SCR in limiting movement. Analysis of the competence to respond to SHR-mediated cell specification activity indicated that it was broadly distributed in the epidermal lineage, while competence to respond to the cell division activity of SHR appeared limited to the initials and involved induction of SCR. The spatial distribution of competence to respond to SHR highlights the importance of tightly regulated movement in generating the root radial pattern.
NLS-dependent nuclear localization of p120ctnis necessary to relieve Kaiso-mediated transcriptional repression
Authors: Kelly Kevin F. , Spring Christopher M. , Otchere Abena A. , Daniel Juliet M.
Published: May 2004

The Armadillo catenin p120ctn regulates cadherin adhesive strength at the plasma membrane and interacts with the novel BTB/POZ transcriptional repressor Kaiso in the nucleus. The dual localization of p120ctn at cell-cell junctions and in the nucleus suggests that its nucleocytoplasmic trafficking is tightly regulated. Here we report on the identification of a specific and highly basic nuclear localization signal (NLS) in p120ctn. The functionality of the NLS was validated by its ability to direct the nuclear localization of a heterologous β-galactosidase-GFP fusion protein. Mutating two key positively charged lysines to neutral alanines in the NLS of full-length p120ctn inhibited both p120ctn nuclear localization as well as the characteristic p120ctn-induced branching phenotype that correlates with increased cell migration. However, while these findings and others suggested that nuclear localization of p120ctn was crucial for the p120ctn-induced branching phenotype, we found that forced nuclear localization of both wild-type and NLS-mutated p120ctn did not induce branching. Recently, we also found that one role of p120ctn was to regulate Kaiso-mediated transcriptional repression. However, it remained unclear whether p120ctn sequestered Kaiso in the cytosol or directly inhibited Kaiso transcriptional activity in the nucleus. Using minimal promoter assays, we show here that the regulatory effect of p120ctn on Kaiso transcriptional activity requires the nuclear translocation of p120ctn. Therefore, an intact NLS in p120ctn is requisite for its first identified regulatory role of the transcriptional repressor Kaiso.
EBV attachment stimulates FHOS/FHOD1 redistribution and co-aggregation with CD21: formin interactions with the cytoplasmic domain of human CD21
Authors: Gill Michael B. , Roecklein-Canfield Jennifer , Sage David R. , Zambela-Soediono Maria , Longtine Nina , Uknis Marc , Fingeroth Joyce D.
Published: May 2004

CD21 is a multifunctional receptor for Epstein-Barr virus (EBV), for C3dg and for CD23. Upon engagement of immune complexes CD21 modulates immunoreceptor signaling, linking innate and adaptive immune responses. The mechanisms enabling CD21 to independently relay information between the exterior and interior of the cell, however, remain unresolved. We show that formin homologue overexpressed in spleen (FHOS/FHOD1) binds the cytoplasmic domain of human CD21 through its C terminus. When expressed in cells, EGFP-FHOS localizes to the cytoplasm and accumulates with actin in membrane protrusions. Plasma membrane aggregation, redistribution and co-localization of both proteins are stimulated when EBV (ligand) binds CD21. Though widely expressed, FHOS RNA is most abundant in the littoral cell, a major constituent of the red pulp of human spleen believed to function in antigen filtration. Formins are molecular scaffolds that nucleate actin by a pathway distinct from Arp2/3 complex, linking signal transduction to actin reorganization and gene transcription. Thus, ligand stimulation of FHOS-CD21 interaction may transmit signals through promotion of cytoskeletal rearrangement. Moreover, formin recruitment to sites of actin assembly initiated by immunoreceptors could be a general mechanism whereby co-receptors such as CD21 modulate intracellular signaling.
The ultrastructure of theChlamydomonas reinhardtiibasal apparatus: identification of an early marker of radial asymmetry inherent in the basal body
Authors: Geimer Stefan , Melkonian Michael
Published: May 2004

The biflagellate unicellular green alga Chlamydomonas reinhardtii is a classic model organism for the analysis of flagella and their organizers, the basal bodies. In this cell, the two flagella-bearing basal bodies, along with two probasal bodies and an array of fibers and microtubules, form a complex organelle called the basal apparatus. The ultrastructure of the basal apparatus was analysed in detail by serial thin-section electron microscopy of isolated cytoskeletons and several newly discovered features are described, including a marker for the rotational asymmetry inherent in the basal bodies and probasal bodies. In addition, the complex three-dimensional basal apparatus ultrastructure is resolved and illustrated, including the attachment sites of all basal apparatus elements to specific microtubular triplets of the basal bodies and probasal bodies. These data will facilitate both the localization of novel basal apparatus proteins and the analysis of mutants and RNA interference cells with only subtle defects in basal apparatus ultrastructure. The early harbinger of radial asymmetry described here could play a crucial role during basal body maturation by orienting the asymmetric attachment of the various associated fibers and therefore might define the orientation of the basal bodies and, ultimately, the direction of flagellar beating.
Organization and dynamics of human mitochondrial DNA
Authors: Legros Frédéric , Malka Florence , Frachon Paule , Lombès Anne , Rojo Manuel
Published: May 2004

Heteroplasmic mutations of mitochondrial DNA (mtDNA) are an important source of human diseases. The mechanisms governing transmission, segregation and complementation of heteroplasmic mtDNA-mutations are unknown but depend on the nature and dynamics of the mitochondrial compartment as well as on the intramitochondrial organization and mobility of mtDNA. We show that mtDNA of human primary and immortal cells is organized in several hundreds of nucleoids that contain a mean of 2-8 mtDNA-molecules each. Nucleoids are enriched in mitochondrial transcription factor A and distributed throughout the entire mitochondrial compartment. Using cell fusion experiments, we demonstrate that nucleoids and respiratory complexes are mobile and diffuse efficiently into mitochondria previously devoid of mtDNA. In contrast, nucleoid-mobility was lower within mitochondria of mtDNA-containing cells, as differently labeled mtDNA-molecules remained spatially segregated in a significant fraction (37%) of the polykaryons. These results show that fusion-mediated exchange and intramitochondrial mobility of endogenous mitochondrial components are not rate-limiting for intermitochondrial complementation but can contribute to the segregation of mtDNA molecules and of mtDNA mutations during cell growth and division.
To Pull or Not to Pull: What Is the Question?
Authors: Hopp Wallace J. , Spearman Mark L.
Published: May 2004

The terms pull and lean production have become cornerstones of modern manufacturing practice. However, although they are widely used, they are less widely understood. In this paper, we argue that while the academic literature has steadily revealed the richness of the pull/lean concepts, the practitioner literature has progressively simplified these terms to the point that serious misunderstandings now exist. In hopes of reducing confusion, we offer general, but precise definitions of pull and lean. Specifically, we argue that pull is essentially a mechanism for limiting WIP, and lean is fundamentally about minimizing the cost of buffering variability.
Coordinating Supply Chains by Controlling Upstream Variability Propagation
Authors: Balakrishnan Anantaram , Geunes Joseph , Pangburn Michael S.
Published: May 2004

Effective distribution using collaborative fulfillment networks requires coordination among the multiple participating firms at different stages of the supply chain. Acting independently, supply chain partners fail to weigh the cost burden they impose on upstream suppliers when their replenishment order quantities vary from period to period. This paper explores a new approach to coordinate multiple stages in the supply chain by controlling, through appropriate downstream inventory management, the demand variability that is propagated to upstream stages. We propose and analyze a coordinated inventory replenishment policy that uses "order smoothing" to reduce order-size variability and thus reduce overall system costs, including both inventory and transportation costs. We characterize the optimal parameter values for smoothing alternatives (such as exponential smoothing and moving weighted average policies), assess their economic benefits, and develop insights regarding supply chain contexts that might benefit most significantly from reducing the variability of orders to upstream stages. Using the distribution network for specialty brand appliances as an illustrative example, we demonstrate the potential cost savings that order-smoothing strategies can yield compared to the uncoordinated case when individual firms separately minimize their costs. The magnitude of savings depends on several factors, including the variability in consumer demand, level of product variety, and degree of inventory aggregation in the distribution system. Based on our analytical results, we develop a framework to assess cost reduction opportunities through variability control for different supply chain scenarios.
Organic Production Systems: What the Biological Cell Can Teach Us About Manufacturing
Authors: Demeester Lieven , Eichler Knut , Loch Christoph H.
Published: May 2004

Biological cells run complicated and sophisticated production systems. The study of the cell's production technology provides us with insights that are potentially useful in industrial manufacturing. When comparing cell metabolism with manufacturing techniques in industry, we find some striking commonalities, but also some important differences. Like today's well-run factories, the cell operates a very lean production system, assures quality at the source, and uses component commonality to simplify production. While we can certainly learn from how the cell accomplishes these parallels, it is even more interesting to look at how the cell operates differently. In biological cells, all products and machines are built from a small set of common building blocks that circulate in local recycling loops. Production equipment is added, removed, or renewed instantly when needed. The cell's manufacturing unit is highly autonomous and reacts quickly to a wide range of changes in the local environment. Although this "organic production system" is very different from existing manufacturing systems, some of its principles are applicable to manufacturing, and indeed, a few can even be seen emerging today. Thus, the organic production system can be viewed as a possible scenario for the future of manufacturing.
How a Base Stock Policy Using "Stale" Forecasts Provides Supply Chain Benefits
Authors: Miyaoka Julia , Hausman Warren
Published: May 2004

Managers often engage in forecast updating with the expectation that forecast updating reduces expected shortage and inventory costs. One undesirable effect of forecast updating is that it may lead to the bullwhip effect, a phenomenon where the variability of demand increases as one moves up the supply chain. The bullwhip effect can be undesirable for the supplier because more volatile orders from the downstream stage can be very costly to the supplier. It can make it more difficult for the supplier to forecast demand, and it can lead to large fluctuations in supplier production levels from period to period. Using "stale" or old forecasts may sound foolish, but their judicious use in a two-stage supply chain can improve fulfillment from the upstream stage to the downstream stage and reduce the fluctuations in production levels. We study a two-stage supply chain where the demand process is nonstationary and both stages use an adaptive base stock policy. We propose a policy that uses old forecasts to set base stock levels at the downstream stage while using current forecasts to communicate upcoming orders from the downstream stage to the upstream stage. We study a decentralized supply chain setting, and we find that our policy can reduce the expected supply chain inventory and shortage costs and significantly reduce the fluctuations in production levels compared to that of using current information. We also study a cooperative supply chain setting and, surprisingly, we find in numerical examples that our proposed policy results in very small increases in the expected systemwide inventory and shortage costs compared to a systemwide optimal policy, while reducing the fluctuations in production levels.
Comparison of Ultracentrifugation and Nuclear Magnetic Resonance Spectroscopy in the Quantification of Triglyceride-Rich Lipoproteins after an Oral Fat Load
Authors: Tsai Michael Y , Georgopoulos Angeliki , Otvos James D , Ordovas Jose M , Hanson Naomi Q , Peacock James M , Arnett Donna K
Published: May 2004

Background: The measurement of triglyceride (TG)-rich particles after an oral fat challenge has been used to provide a measure of risk for coronary artery disease independent of the fasting plasma triglyceride concentration. The analytical “gold standard” for measuring TG-rich lipoproteins uses density gradient ultracentrifugation; however, this technique is labor-intensive. Because of our need to perform numerous postprandial analyses of TG-rich lipoproteins for a large interventional study (Genetics of Lipid Lowering Drugs and Diet Network), we evaluated the use of nuclear magnetic resonance (NMR) spectroscopy for measuring TG-rich particles.

Methods: EDTA-blood samples were obtained 0, 3.5, 6, and 8 h after ingestion of an oral fat meal (89% of calories from fat) in 20 apparently healthy individuals. The plasma TG concentrations of chylomicron and chylomicron remnant/VLDL fractions were analyzed by ultracentrifugation and NMR spectroscopy.

Results: Comparison of all values (n = 78) by ultracentrifugation (x) and NMR (y) produced a linear regression equation of y = 0.979x − 0.035 mmol/L (R2 = 0.90) for chylomicrons and y = 1.398x + 0.067 mmol/L (R2 = 0.96) for the fraction containing chylomicron remnants and VLDL. Postprandial response of chylomicrons and chylomicron remnant/VLDL was similar, with maximum response occurring between 3.5 to 6 h regardless of method of measurement.

Conclusion: Chylomicron and chylomicron remnant/VLDL fraction measurements obtained by NMR have a high degree of correlation with results produced by ultracentrifugation. NMR may therefore be suitable as an alternative method for the measurement of postprandial TG-rich lipoproteins in individuals consuming a high-fat meal.
Web Usability-Tests mit qualitativen Methoden am Beispiel von Online-Fokusgruppen (Web Usability-Testing and Qualitative Methods – A Case-Study with Online-Focus Groups)
Authors: Yom Miriam , Wilhelm Thorsten
Published: May 2004

Fokusgruppen und insbesondere ihre Online-Variante sind im Kontext der nutzerbasierten Usability-Beurteilung noch wenig untersucht. Es stellt sich die Frage, welche Effekte die spezielle Kommunikationssituation in Online-Fokusgruppen (im Weiteren OFGs) auf die Qualität und Verwertbarkeit der Daten hat. In diesem Artikel werden die konstituierenden Merkmale der synchronen computervermittelten Kommunikation (im Weiteren cvK) und somit relevanten Determinanten der Datenqualität von OFGs dargestellt. Des Weiteren stellen wir Ergebnisse eines Methodenvergleichs zwischen konventionellen Fokusgruppen im Labor und OFGs bei der Beurteilung eines Online-Reiseshops vor. Es zeigte sich, dass durch Kommunikationstraining und technische Unterstützung die Defizite der synchronen Online-Kommunikation ausgeglichen werden können. Anhand einer deskriptiven Themenanalyse konnte gezeigt werden, dass es starke Überschneidungen der Aussagen in den beiden Kommunikationsbedingungen gibt.
Gestalten von sinnesübergreifenden Mixed-Reality-Lernräumen im Schulunterricht (Design of Multi-Sensory Mixed-Reality Learning Environments in School Education)
Authors: Winkler Thomas , Herczeg Michael
Published: May 2004

Der Beitrag diskutiert die kombinierte und fachübergreifende ästhetische und informatische Bildung im Schulunterricht. Es wird erläutert, wie durch die Kombination von kostenlosen oder kostengünstigen Hard- und Software-Lösungen Mixed-Reality-Lernumgebungen geschaffen werden können. Durch das Zusammenführen von sinnlicher Wahrnehmen und der Co-Konstruktion von Wissen entsteht eine wirkungsvolle Form von erlebnisbasiertem Lernen.
SOUTHEAST ASIA IN A NEW ERA: Domestic Coalitions from Crisis to Recovery
Authors: Solingen Etel
Published: May 2004

The crisis of 1997–98 unleashed the most severe challenge to Southeast Asian ruling coalitions in decades. This article examines the domestic political consequences of the crisis, focusing on continuity and change in fundamental coalitional forms. Despite initial concerns with a potential backlash, internationalizing coalitions stayed the course while adapting to new political-institutional requirements imposed by the growing salience of social dimensions of internationalization. Yet, the longer-term distributional and political effects of the crisis may not be evident for some time.
WHY IS ASEAN DIPLOMACY CHANGING? From “Non-Interference” to “Open and Frank Discussions”
Authors: Katsumata Hiro
Published: May 2004

A conventional/rationalist explanation holds that the ASEAN countries have begun to have open and frank discussions in order to deal with new challenges, such as economic and environmental issues, in an efficient way. Constructivists explain ASEAN's change by focusing on the global normative shift, which emphasizes human rights and democracy.
MIGRATION OF FOREIGN WORKERS INTO SOUTH KOREA: From Periphery to Semi-Periphery in the Global Labor Market
Authors: Kim Wang-Bae
Published: May 2004

The rapid wage increase and labor shortage since the late 1980s in South Korea forced the government to allow the employment of workers from numerous Asian countries. However, unforeseen problems arose when many foreign workers remained illegally, and growing awareness of their plight raised social and human rights concerns.
The Synthesis and Electronic Structure of a Novel [Ni‘S4’Fe2(CO)6] Radical Cluster: Implications for the Active Site of the [NiFe] Hydrogenases
Authors: Wang Qiang , Barclay J. Elaine , Blake Alexander J. , Davies E. Stephen , Evans David J. , Marr Andrew C. , McInnes Eric J. L. , McMaster Jonathan , Wilson Claire , Schröder Martin
Published: May 2004

A novel [Ni‘S4’Fe2(CO)6] cluster (1: ‘S4’=(CH3C6H3S2)2(CH2)3) has been synthesised, structurally characterised and has been shown to undergo a chemically reversible reduction process at −1.31 V versus Fc+/Fc to generate the EPR‐active monoanion 1−. Multifrequency Q‐, X‐ and S‐band EPR spectra of 61Ni‐enriched 1− show a well‐resolved quartet hyperfine splitting in the low‐field region due to the interaction with a single 61Ni (I=3/2) nucleus. Simulations of the EPR spectra require the introduction of a single angle of non‐coincidence between g1 and A1, and g3 and A3 to reproduce all of the features in the S‐ and X‐band spectra. This behaviour provides a rare example of the detection and measurement of non‐coincidence effects from frozen‐solution EPR spectra without the need for single‐crystal measurements, and in which the S‐band experiment is sensitive to the non‐coincidence. An analysis of the EPR spectra of 1− reveals a 24 % Ni contribution to the SOMO in 1−, supporting a delocalisation of the spin‐density across the NiFe2 cluster. This observation is supported by IR spectroscopic results which show that the CO stretching frequencies, ν(CO), shift to lower frequency by about 70 cm−1 when 1 is reduced to 1−. Density functional calculations provide a framework for the interpretation of the spectroscopic properties of 1− and suggest that the SOMO is delocalised over the whole cluster, but with little S‐centre participation. This electronic structure contrasts with that of the Ni‐A, ‐B, ‐C and ‐L forms of [NiFe] hydrogenase in which there is considerable S participation in the SOMO.
Induction of somatic hypermutation by antigen‐specific B cell receptors in the human BL2 cell line
Authors: Glaudet Florence , Denis Vincent , Cogné Michel , Khamlichi Ahmed Amine
Published: May 2004

The role of the B cell antigen receptor in the induction of somatic hypermutation is presently unclear. We established stable transfectants of the human BL2 cell line expressing hen‐egg lysozyme‐specific IgM or IgA and compared their ability to induce somatic hypermutation of the endogenous rearranged heavy‐chain gene. We found that IgM and IgA were both able to induce somatic hypermutation in an antigen dose‐independent manner. The mutations displayed most of the characteristics of somatic hypermutation in vivo. Notably, some replacements introduced stop codons in the coding region. Our data suggest that class‐switched memory B cells may undergo somatic hypermutation. They also suggest that the transmembrane/cytoplamic domains of the class‐switched isotypes modulatethe signaling and down‐modulation activities of the BCR in an antigen dose‐dependent manner.