bluuebunny/crossref_metadata_2025 huggingface dataset:
Dopamine D
1
Receptor Augmentation of D
3
Receptor Action in Rat Aortic or Mesenteric Vascular Smooth Muscles
Authors: Zeng Chunyu , Wang Dan , Yang Zhiwei , Wang Zheng , Asico Lareano D. , Wilcox Christopher S. , Eisner Gilbert M. , Welch William J. , Felder Robin A. , Jose Pedro A.
Published: February 2004

Dopamine is an important modulator of blood pressure, in part, by regulating vascular resistance. To test the hypothesis that D
1
and D
3
receptors interact in vascular smooth muscle cells, we studied A10 cells, a rat aortic smooth muscle cell line, and rat mesenteric arteries that express both dopamine receptor subtypes. Fenoldopam, a D
1
-like receptor agonist, increased both D
1
and D
3
receptor protein in a time-dependent and a concentration-dependent manner in A10 cells. The effect of fenoldopam was specific because a D
1
-like receptor antagonist, SCH23390 (10
−7
M/24 h), completely blocked the stimulatory effect of fenoldopam (10
−7
M/24 h) (D
3
receptor: control=21±1 density units [DU]); SCH23390=23±2 DU; fenoldopam=33±2 DU; fenoldopam+SCH23390=23±2 DU; n=10). D
1
and D
3
receptors physically interacted with each other because fenoldopam (10
−7
M/24 h) increased D
1
/D
3
receptor coimmunoprecipitation (35±5 versus 65±5 DU; n=8). A D
3
receptor agonist, PD128907, relaxed mesenteric arterial rings independent of the endothelium, effects that were blocked by a D
3
receptor antagonist, U99194A. Costimulation of D
1
and D
3
receptors led to additive vasorelaxation. We conclude that the D
1
receptor regulates the D
3
receptor by physical interaction and receptor expression. D
1
receptor stimulation augments D
3
receptor vasorelaxant effects. An interaction of D
1
and D
3
receptors may be involved in the regulation of blood pressure.
Concordance Rate Differences of 3 Noninvasive Imaging Techniques to Measure Carotid Stenosis in Clinical Routine Practice
Authors: Nonent Michel , Serfaty Jean-Michel , Nighoghossian Norbert , Rouhart François , Derex Laurent , Rotaru Carmen , Chirossel Pierre , Guias Bruno , Heautot Jean-François , Gouny Pierre , Langella Bernard , Buthion Valérie , Jars Isabelle , Pachai Chahin , Veyret Charles , Gauvrit Jean-Yves , Lamure Michel , Douek Philippe C.
Published: February 2004

Background and Purpose—

To replace digital subtraction angiography (DSA) in carotid stenosis evaluation, noninvasive imaging techniques have to reach a high concordance rate. Our purpose is to compare the concordance rates of contrast-enhanced MR angiography (CEMRA) and CT angiography (CTA) with Doppler ultrasound (DUS) in clinical routine practice.

Methods—

We evaluated prospectively with DUS, CEMRA, and CTA 150 patients suspected of carotid stenosis. The overall concordance rates of the 3 techniques were calculated for symptomatic stenosis ≥50% and ≥70%, for asymptomatic stenosis ≥60%, and for occlusion. For the carotid arteries treated by surgery (n=97), the results of each method and combined techniques were recorded, and misclassification rates were evaluated from surgical reports.

Results—

The overall concordance rates of DUS-CEMRA, DUS-CTA, and CEMRA-CTA were not statistically different. However, the concordance rate of DUS-CEMRA (92.53%) was significantly higher than that for DUS-CTA (79.10%) in the surgical asymptomatic stenosis group (
P
=0.0258). CTA considered alone would misclassify the stenosis in a significant number of cases (11 of 64) in the surgical asymptomatic group compared with CEMRA (3 of 67) and DUS (1 of 66) (
P
=0.0186 versus MRA,
P
=0.0020 versus DUS).

Conclusions—

With the techniques as utilized in our study, the overall concordance rates of combined noninvasive methods are similar for measuring carotid stenosis in clinical routine practice, but in asymptomatic carotid stenosis, the decision making for surgery is significantly altered if DUS and CTA are considered in place of DUS and CEMRA.
Anticardiolipin Antibodies and Risk of Ischemic Stroke and Transient Ischemic Attack
Authors: Janardhan Vallabh , Wolf Philip A. , Kase Carlos S. , Massaro Joseph M. , D’Agostino Ralph B. , Franzblau Carl , Wilson Peter W.F.
Published: February 2004

Background and Purpose—

The role of anticardiolipin antibodies (aCLs) as novel risk factors for ischemic stroke and transient ischemic attacks (TIAs) has been a matter of debate. Prior cohort studies included only selected subjects, mostly men. We related serum concentrations of aCLs to incident first ischemic stroke/TIA among men and women in the Framingham Heart Study cohort and offspring.

Methods—

There were a total of 2712 women (mean age, 59.3 years) and 2262 men (mean age, 58.3 years) free of stroke/TIA at the time of their baseline examinations. An enzyme immunoassay was used to measure aCLs. Optical density of the sample serum compared with the reference serum was defined as the aCL screening ratio (aCL SR). Analyses were based on sex-specific aCL SR quartiles and individual ratios.

Results—

During the 11-year follow-up, 222 ischemic strokes/TIAs occurred. In multivariate analysis, after adjustment for age, prior cardiovascular disease, systolic blood pressure, diabetes, smoking, C-reactive protein, and total and high-density lipoprotein cholesterol levels, an aCL SR of >0.4 (78% of sample) was significantly associated with an increased risk of ischemic stroke/TIA for women (hazard ratio [HR], 2.6; 95% confidence interval [CI], 1.3 to 5.4; absolute risk, 3.2%, 95% CI, 2.2 to 4.3) but not in men (HR, 1.3; 95% CI, 0.7 to 2.4; absolute risk, 4.5%; 95% CI, 3.0 to 6.0). Similar results were obtained when the higher 3 aCL SR quartiles were compared with the lowest.

Conclusions—

Elevated serum concentrations of aCLs, independently of other cardiovascular risk factors, significantly predict the risk of future ischemic stroke and TIA in women but not in men.
A Pleistocene amphisbaenian from Sicily
Authors: Delfino Massimo
Published: February 2004

Recent analysis of the fossil herpetofauna recovered from the latest Middle or earliest Late Pleistocene layers of the site called "K 22" (San Vito Lo Capo, TP, Sicily) revealed the presence of a single vertebra that unquestionably belongs to the order Amphisbaenia. Although it is not possible to assign it at family level, the presence of an undetermined amphisbaenian in the Pleistocene of Sicily represents the last European occurrence of this order outside the present range corroborating the idea that the modern Italian herpetofauna is relatively impoverished if compared to the Pleistocene one, and that this loss of biodiversity not only affected the peninsula but its islands also.
Reproduction in the nest building vizcacheras frog Leptodactylus bufonius in central Argentina
Authors: Jofré G.M. , Reading C.J.
Published: February 2004

A population of vizcacheras frogs Leptodactylus bufonius was studied at a man-made pond in the north of Córdoba Province in central Argentina during December 2000 and 2001. Breeding females were larger than breeding males with both sexes attaining sexual maturity at two years of age and most living to a maximum age of four years. The sex ratio of the breeding population was approximately 1.2♂ : 1♀. Although the numbers of eggs and tadpoles found in sealed nests was the same as the number of eggs found in the ovaries of unspawned females, between-year differences in egg production per female were found. Nests were constructed by males, at night, and then abandoned for at least 24 hours. Amplexus and spawning occurred within the nest. The nest was then vacated and the female sealed the nest aperture with wet mud. The minimum and maximum temperatures recorded inside sealed nests were less extreme than those recorded outside the nest.
Hibernation, habitat and seasonal activity in the adder, Vipera berus, north of the Arctic Circle in Sweden
Authors: Andersson Stefan
Published: February 2004

This study concerns five of the northernmost adder, Vipera berus, localities in the world that are situated in the basins of Tornio, Lainio and Vittangi rivers, between 300 and 450 m.a.sl. The study area lies approximately 150 km north of the Arctic Circle in northern Sweden. Three different kinds of slopes were used as hibernation sites, slopes on moraine ridges, slopes in canyons and on mountains. All were characterized by stony south facing slopes without topsoil and shading trees. Open areas of peat bogs and marshlands were always found within a kilometre's distance from the hibernation sites. Except pregnant females that remained around the hibernation sites, the adders were found feeding on voles in these areas from mid-June to mid-August showing a distinct shift in habitat use between seasons. The total length of the activity period was found to be 17-18 weeks.
Individual Variation in the Strength of Territory Defense in Male Song Sparrows: Correlates of Age, Territory Tenure, and Neighbor Aggressiveness
Authors: Hyman Jeremy , Hughes Melissa , Nowicki Stephen , Searcy William
Published: February 2004

In many species, the ability to defend a territory is essential for a male to obtain any reproductive success at all, and even among territorial individuals, variation in the strength of territory defense could have a significant impact on how much reproductive success is obtained. Previous studies have documented consistent individual differences in the vigor with which male song sparrows (Melospiza melodia) defend their territories, as measured by the strength of their reactions to territorial intrusions simulated through song playback. Variation in the strength of defense could reflect intrinsic differences among individuals in their resource holding potential (RHP), or variation in extrinsic factors. In this study, we examined whether variation in the strength of territory defense corresponds to differences in intrinsic factors such as the age or experience of the territory owner, the extrinsic factor of the level of aggression shown by neighbours, or both. Results indicate that males that previously held territories on the study site, regardless of whether they were holding the same territory as the previous year, show higher levels of territory defense than males that are new to the study site, and, assuming that returning males are older males, suggest that age is more important than experience on a specific territory in determining strength of territory defense. In addition, we found evidence that males with high levels of territorial aggression tend to be spatially clustered. The pattern observed suggests that a combination of intrinsic and extrinsic factors contribute to the expression of individual differences in territorial aggression.
Thomas Langurs (Presbytis thomasi) Discriminate Between Calls of Young Solitary Versus Older Group-living Males: a Factor in Avoiding Infanticide?
Authors: Assink  , Sterck  , Wich
Published: February 2004

The ability to differentiate among calls from different individuals has been shown for a number of animal species and several functions have been suggested. One hypothesis, developed for lions (Panthera leo), is that the ability to distinguish between calls from neighbour versus strange males is linked to the avoidance of infanticidal ( i.e. strange) males. Since infanticide is widespread among primates, we tested the applicability of this hypothesis to Thomas langurs (Presbytis thomasi). Young adult males, that mostly reside in all-male bands or are solitary (called AMB males), were more likely to be infanticidal than adult, usually older, males that reside in mixed-sex groups (called MSG males). We use playbacks to demonstrate that Thomas langurs are able to differentiate between loud calls from AMB male strangers and MSG male strangers. Thomas langur males responded more vigorously to playbacks of calls from AMB (i.e. more likely to be infanticidal) males than to calls from MSG males. Females showed a more cautious response to the calls from AMB males than to the calls from MSG males. Both these reactions are in accordance with the infanticide hypothesis and suggest that Thomas langurs differentiate between loud calls of AMB and MSG stranger males and incorporate this information in their behaviour to avoid infanticide.
Female Social Relationships of Cebus apella nigritus in a Southeastern Atlantic Forest: An Analysis Through Ecological Models of Primate Social Evolution
Authors: Izar Patrícia
Published: February 2004

Theoretical models about female relationships within primate social groups hypothesise that food abundance and distribution are important factors determining the variation of patterns observed among species and populations. Despite some common premises, models formulated by van Schaik (1989) and Sterck et al. (1997) and by Isbell (1991) differ with respect to the importance of predation risk, the co-variation of contest and scramble competition and causes of female dispersal. In this study, data from a population of Cebus apella nigritus from Brazilian Atlantic Forest are analysed using predictions from these models. Competition among females, both within and between groups, is strong and related to food abundance and distribution. Females can transfer between groups, as well as males. Female dispersal is related to a significant reduction in per capita energy intake by group foragers during fruit scarcity periods. The data from this study are not conclusive about the importance of predation in causing variation of female relationships but favour the assumption from van Schaik and Sterck et al. that contest and scramble competition within and between groups can vary independently; and also favour the formulation from Isbell & Van Vuren (1996) on female dispersal. The exact pattern of female social relationships is not sufficiently explained by ecological causes alone. Social benefits provided by the dominant male also seem to be important.
Chickadee Song Structure is Individually Distinctive Over Long Broadcast Distances
Authors: Christie Peter , Mennill Daniel , Ratcliffe Laurene
Published: February 2004

The two-note fee-bee song of male black-capped chickadees functions during the dawn chorus, in part, as a sexual signal across large distances. How song structure might encode information about male quality, however, remains unclear. We studied the availability of cues to male social rank (a proxy indicator of male quality), within the acoustic structure of dawn chorus songs of male chickadees whose flock dominance status we determined the previous winter. We used analysis of variance and discriminant function analysis to demonstrate that five temporal, frequency or relative amplitude features of song can predict individual identity but not the category of social rank (dominant versus subordinate) to which individuals belong. After transmitting chickadee songs through the forest and re-recording them at four broadcast distances, we found that song structure continued to effectively predict singer identity by our statistical methods despite significant acoustic degradation for as long as songs remained audible (up to 80 m). In particular, the relative frequency interval between the two notes is both the most invariant between-male measure and among the most individually distinctive. We conclude the structure of dawn chorus songs could function across large distances to signal the identity of familiar singing males whose relative quality is known to the listener from other interactions (such as encounters within winter flocks).
East African Monetary Union: The Domestic Politics of Institutional Survival and Dissolution
Authors: Cooper Scott , Asay Clark
Published: February 2004

Many regional currency institutions were established in subSaharan Africa under colonial rule. Surprisingly, a number of these colonial institutions survived the transition to national independence, and several have survived to the present day (e.g., the West African franc zones and the Southern African rand zone). In order to understand why some of these regional institutions survived while others collapsed, we have to look carefully at member countries' domestic politics at the time of independence. This study looks at the stop-and-go pattern of postcolonial cooperation in East Africa to provide an understanding of the choice between regional cooperation and the breakup of regional institutions. Newly independent governments in Kenya, Uganda, and Tanzania faced a choice between continuing regional institutional ties and dissolving regional institutions to issue their own national currencies. We argue that governments maintained regional currencies only when past institutions had created a domestic political constituency for continued regionalism. The most important historical legacy of colonial institutions was the way domestic political coalitions were reshaped. This study suggests, therefore, that there is a political mechanism to path dependence: past institutions continue to shape the present through changes in political alignments.
This is What Democracy Looks Like: Globalization, New Information Technology and the Trade Policy Process: Some Comparative Observations
Authors: Smith Peter , Smythe Elizabeth
Published: February 2004

This article examines the process by which economic globalization and the Internet have facilitated the proliferation and mobilization of nongovernmental organizations (NGOs) and social movements that are challenging the negotiation of trade rules through the World Trade Organization (WTO). Our focus, however, is not on the WTO per se but on the impact that globally-articulated local networks are having on the national trade policy processes of Canada, Australia, and the European Union (EU), all members of the WTO. We discuss how local networks of NGOs and social movements are inserted into, and relate to, larger global coalitions and global information networks from which they draw support and sustenance. Finally, we compare how local institutions, processes, and histories have shaped the dialogue and interaction of NGOs with trade departments that are occurring at the level of these nation-states and the European Union.
Circulative Linkages of Regional Knowledge Activities: Empirical Evidence from the Korean Case
Authors: Lee Kongrae
Published: February 2004

This paper argues that there are circulative linkages between knowledge creation, sharing and utilization in regional innovative clusters. Based upon discussions about characteristics of circulative linkages between three types of knowledge activities, this paper presents three hypotheses: the more regions generate knowledge, the more active they tend to share knowledge; the more regions share knowledge, the more vigorous they tend to utilize knowledge; and the more regions generate knowledge, the more vigorously they utilize knowledge. Empirical analysis into the South Korean case showed that regions with higher knowledge generation have stronger knowledge-sharing and knowledge-utilization activities, strongly supporting the hypotheses. However, taking a weak corelation between knowledge sharing and knowledge utilization into account, it is suggested that regions with active knowledge sharing do not automatically lead to stronger knowledge utilization. There should be an effective policy measure for leading active knowledge sharing to active knowledge utilization. This study helps guide provincial governments in choosing policy goals to promote knowledge activities so as to accelerate regional innovation. It also leads to the conclusion that maintaining balance among the three types of knowledge activities (creation, sharing, and utilization) is a way to make policies that promote regional innovative clusters.
Indonesian Political Laws in Habibie Era: Between Political Struggle and Law Reform
Authors: Hosen Nadirsyah
Published: February 2004

Following the resignation of President Soeharto in May 1998, political and civic leaders,along withgovernmental officials,began the process of developing a new political system. The most important step was to create a new legal framework for early national elections. New political laws governing elections, political parties and the structure of legislative bodies were signed by President B.J. Habibie on 1 February 1999. The article examines the three 1999 political laws at three levels: political and legal processes, content and implementation. The article argues that those laws were a reflection of political compromise and, therefore, did not meet demands for genuine reform: promoting good governance and the rule of law.
Characterization of childhood acute lymphoblastic leukemia xenograft models for the preclinical evaluation of new therapies
Authors: Liem Natalia L. M. , Papa Rachael A. , Milross Christopher G. , Schmid Michael A. , Tajbakhsh Mayamin , Choi Seoyeon , Ramirez Carole D. , Rice Alison M. , Haber Michelle , Norris Murray D. , MacKenzie Karen L. , Lock Richard B.
Published: February 2004

Continuous xenografts from 10 children with acute lymphoblastic leukemia (ALL) were established in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Relative to primary engrafted cells, negligible changes in growth rates and immunophenotype were observed at second and third passage. Analysis of clonal antigen receptor gene rearrangements in 2 xenografts from patients at diagnosis showed that the pattern of clonal variation observed following tertiary transplantation in mice exactly reflected that in bone marrow samples at the time of clinical relapse. Patients experienced diverse treatment outcomes, including 5 who died of disease (median, 13 months; range, 11-76 months, from date of diagnosis), and 5 who remain alive (median, 103 months; range, 56-131 months, following diagnosis). When stratified according to patient outcome, the in vivo sensitivity of xenografts to vincristine and dexamethasone, but not methotrexate, differed significantly (P = .028, P = .029, and P = .56, respectively). The in vitro sensitivity of xenografts to dexamethasone, but not vincristine, correlated significantly with in vivo responses and patient outcome. This study shows, for the first time, that the biologic and genetic characteristics, and patterns of chemosensitivity, of childhood ALL xenografts accurately reflect the clinical disease. As such, they provide powerful experimental models to prioritize new therapeutic strategies for future clinical trials.
Familial essential thrombocythemia associated with a dominant-positive activating mutation of the c-MPL gene, which encodes for the receptor for thrombopoietin
Authors: Ding Jianmin , Komatsu Hirokazu , Wakita Atsushi , Kato-Uranishi Miyuki , Ito Masato , Satoh Atsushi , Tsuboi Kazuya , Nitta Masakazu , Miyazaki Hiroshi , Iida Shinsuke , Ueda Ryuzo
Published: February 2004

One Japanese pedigree of familial essential thrombocythemia (FET) inherited in an autosomal-dominant manner is presented. A unique point mutation, serine 505 to asparagine 505 (Ser505Asn), was identified in the transmembrane domain of the c-MPL gene in all of the 8 members with thrombocythemia, but in none of the other 8 unaffected members in this FET family. The Ba/F3 cells expressing the mutant Asn505 acquired interleukin 3 (IL-3)-independent survival capacity, whereas those expressing wild-type Ser505 did not. The autonomous phosphorylation of Mek1/2 and Stat5b was observed in the mutant Ba/F3 cells in the absence of IL-3. The former was also found in platelets derived from the affected individual in the absence of thrombopoietin. These results show that the Asn505 is an activating mutation with respect to the intracellular signaling and survival of the cells. This is the first report of FET deriving from a dominant-positive activating mutation of the c-MPL gene. (Blood. 2004;103: 4198-4200)
Dynamics of cytokine expression in HIV productively infected primary CD4+ T cells
Authors: Bahbouhi Bouchaib , Landay Alan , Al-Harthi Lena
Published: February 2004

Using intracellular p24 staining to discriminate between bystander and HIV productively infected cells, we evaluated the properties of HIV productively infected cells in terms of cytokine expression, activation status, apoptosis, and cell proliferation. We demonstrate that HIV productively infected primary CD4+ T cells express 12- to 47-fold higher type 1 cytokines than bystander or mock-infected cells. The frequency of HIV productive replication occurred predominantly in T-helper 1 (Th1), followed by Th0, then by Th2 cells. These productively infected cells expressed elevated levels of CD95, CD25, CXC chemokine receptor 4 (CXCR4), and CC chemokine receptor 5 (CCR5). While productively infected cells were only 1.8-fold higher in apoptosis frequency, they up-regulated the antiapoptotic protein B-cell leukemia 2 (Bcl-2) by 10-fold. Up-regulation of interleukin-2 (IL-2) and Bcl-2 were dependent on phosphatidylinositol-3-kinase signal transduction, given that it was down-regulated by Wortmanin treatment. Additionally, 60% of productively infected cells entered the cell cycle, as evaluated by Ki67 staining, but none divided, as evaluated by carboxyfluoresccin diacetate succinimidyl ester (CFSE) staining. Evaluation of cell cycle progression by costaining for DNA and RNA indicated that the cells were arrested in G2/M. Collectively, these data indicate that HIV replication occurs predominantly in Th1 cells and is associated with immune activation and up-regulation of Bcl-2, conferring a considerable degree of protection against apoptosis in the productively infected subpopulation. (Blood. 2004;103:4581-4587)
Substitution of the γ-chain Asn308 disturbs the D:D interface affecting fibrin polymerization, fibrinopeptide B release, and FXIIIa-catalyzed cross-linking
Authors: Okumura Nobuo , Gorkun Oleg V. , Terasawa Fumiko , Lord Susan T.
Published: February 2004

Crystallographic structures indicate that γ-chain residue Asn308 participates in D:D interactions and indeed substitutions of γAsn308 with lysine or isoleucine have been identified in dysfibrinogens with impaired polymerization. To probe the role of Asn308 in polymerization, we synthesized 3 variant fibrinogens: γAsn308 changed to lysine (γN308K), isoleucine (γN308I), and alanine (γN308A). We measured thrombin-catalyzed polymerization by turbidity, fibrinopeptide release by high-performance liquid chromatography, and factor XIIIa–catalyzed cross-linking by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. In the absence of added calcium, polymerization was clearly impaired with all 3 variants. In contrast, at 0.1 mM calcium, only polymerization of γN308K remained markedly abnormal. The release of thrombin-catalyzed fibrinopeptide B (FpB) was delayed in the absence of calcium, whereas at 1 mM calcium FpB release was delayed only with γN308K. Factor XIIIa–catalyzed γ-γ dimer formation was delayed with fibrinogen (in absence of thrombin), whereas with fibrin (in presence of thrombin) γ-γ dimer formation of only γN308K was delayed. These data corroborate the recognized link between FpB release and polymerization. They show fibrin cross-link formation likely depends on the structure of protofibrils. Together, our results show substitution of Asn308 with a hydrophobic residue altered neither polymer formation nor polymer structure at physiologic calcium concentrations, whereas substitution with lysine altered both.
Reduced GRK2 level in T cells potentiates chemotaxis and signaling in response to CCL4
Authors: Vroon Anne , Heijnen Cobi J , Lombardi Maria Stella , Cobelens Pieter M , Mayor Federico , Caron Marc G , Kavelaars Annemieke
Published: February 2004

Chemokine receptors belong to the family of G-protein-coupled receptors (GPCR). Phosphorylation of GPCR by GPCR kinases (GRKs) is considered to play an important role in desensitization of these receptors. We have recently shown in patients with rheumatoid arthritis that the level of GRK2 in lymphocytes is reduced by ∼50%. However, the physiological relevance of reduced GRK2 levels in lymphocytes is not known. Here, we investigated whether reduced GRK2 expression changes the chemotactic response of T cells to the chemokines CCL3, CCL4, and CCL5. Activated T cells from GRK2+/− mice, which have a 50% reduction in GRK2 protein levels, showed a significant 40% increase in chemotaxis toward the CCR5 ligand CCL4. In addition, chemotaxis toward the CCR1 and CCR5 ligands CCL3 and CCL5 was also increased. Binding of CCL4 to activated T cells from GRK2+/− and wild-type (WT) mice was similar, but agonist-induced CCR5 phosphorylation was attenuated in GRK2+/− cells. Moreover, the calcium response and phosphorylation of protein kinase B and extracellular-regulated kinase in response to CCL4 were significantly increased in GRK2+/− T cells, showing that signaling is increased when the level of GRK2 is reduced. GRK2+/− and WT cells do become refractory to restimulation with CCL4. In conclusion, a 50% decrease in T cell GRK2 expression results in increased responsiveness to CCL3, CCL4, and CCL5, suggesting that the 50% reduction in lymphocyte GRK2 level as observed during inflammation can have functional consequences for the response of these cells to chemokines.
Mannose-binding lectin deficiency alters the development of fungal asthma: effects on airway response, inflammation, and cytokine profile
Authors: Hogaboam Cory M , Takahashi Kazue , Ezekowitz R Alan B , Kunkel Steven L , Schuh Jane M
Published: February 2004

Aspergillus fumigatus is a major fungal pathogen that may be fatal to immunocompromised individuals and causes airway hyperreactivity and remodeling in sensitized individuals. Herein, we examined the role of mannose-binding lectin (MBL), a complement-activating plasma protein, during ulmonary innate and allergic immune responses directed against A. fumigatus spores or conidia. Neither group of nonsensitized MBL-A-sufficient (MBL-A+/+) nor -deficient (MBL-A−/−) mice challenged with an intravenous or intratracheal (i.t.) bolus of A. fumigatus spores experienced fungus-induced mortality, but marked airway remodeling was observed in MBL-A−/− mice challenged i.t. with conidia. In a model of chronic fungal asthma, MBL-A+/+ and MBL-A−/− A. fumigatus-sensitized mice were examined at days 4 and 28 after an i.t. challenge with A. fumigatus conidia. Airway hyperresponsiveness in sensitized MBL-A−/− mice was significantly decreased at both times after conidia challenge compared with the sensitized MBL-A+/+ group. In the sensitized MBL-A−/− mice, whole lung T helper cell type 2 cytokine levels were significantly decreased at day 4 after conidia, and whole lung interferon-γ levels were significantly increased at day 28 after conidia when compared with controls. However, histological evidence showed similar airway remodeling at day 28 after conidia (i.e., subepithelial fibrosis and goblet cell metaplasia) in the two groups of mice. Thus, these findings show that MBL-A is not required for mouse survival following exposure to A. fumigatus conidia, and this murine collectin isoform contributes to the development and maintenance of airway hyperresponsiveness but not chronic airway remodeling during chronic fungal asthma.
Differential gene expression profile of human tonsil high endothelial cells: implications for lymphocyte trafficking
Authors: Palmeri Diana , Zuo Feng-Rong , Rosen Steven D , Hemmerich Stefan
Published: February 2004

Lymphocyte recirculation is dependent on the interactions of adhesion and signaling molecules expressed on lymphocytes and their partners on high endothelial cells (HEC). Many of the events in this process have yet to be molecularly characterized. To identify novel HEC-specific proteins with potential function in the recruitment cascade, we sequenced a normalized human tonsil HEC cDNA library (generated from an inflamed tonsil) from which lymphocyte and human umbilical vein endothelial cell cDNAs had een subtracted. One-thousand forty-nine sequences were analyzed. All but three mapped to known cDNAs or genomic DNAs. The two most abundant transcripts encoded α2-macroglobulin and hevin. The next-abundant transcripts encoded several other protease inhibitors, making this protein class the most prominent in HEC. Several endothelial-specific transcripts were also identified, including those encoding E-selectin, vascular cell adhesion molecule-1, vascular endothelial-junctional adhesion molecule, and platelet-endothelial cell adhesion molecule-1. The library contains a great diversity of transcripts, and studies of the encoded proteins will provide further insight into the complex biology of these specialized endothelial cells.
Immature dendritic cells reduce proinflammatory cytokine production by a coculture of macrophages and apoptotic cells in a cell-to-cell contact-dependent manner
Authors: Takahashi Munehisa , Kurosaka Kahori , Kobayashi Yoshiro
Published: February 2004

We have demonstrated that phagocytosis of late apoptotic cells by mouse macrophages leads to the production of proinflammatory cytokines, notably macrophage-inflammatory protein (MIP-2), and therefore, a yet-unknown mechanism(s) should keep our body free of inflammation. In this study, we examined the effect of the addition of immature dendritic cells (iDCs) to a coculture of macrophages and apoptotic cells on MIP-2 production and phagocytosis by macrophages. The addition of iDCs to the coculture reduced MIP-2 production significantly but unexpectedly enhanced the phagocytosis by macrophages. Further study revealed that the reduction of MIP-2 production was dependent on cell-to-cell contact partly involving the β2 integrin family Mac-1. In addition, anti-inflammatory cytokines, interleukin-10 and transforming growth factor-β, were involved in the reduction of MIP-2 production, as antibodies against these cytokines recovered MIP-2 production. Both cytokines were expressed by iDCs more sigificantly than macrophages at the mRNA levels, although they were hardly detected in the supernatant at the protein levels, suggesting that minute amounts of these anti-inflammatory cytokines were produced mainly by iDCs to block MIP-2 production in a cell-to-cell contact-dependent manner. Thus, this study reveals a new mechanism by which MIP-2 production by macrophages phagocytosing apoptotic cells is prevented.
Mechanisms of glucocorticoid-induced down-regulation of neutrophil L-selectin in cattle: evidence for effects at the gene-expression level and primarily on blood neutrophils
Authors: Weber Patty S D , Toelboell Trine , Chang Ling-Chu , Tirrell Janelle Durrett , Saama Peter M , Smith George W , Burton Jeanne L
Published: February 2004

One anti-inflammatory action of glucocorticoids is down-regulation of surface L-selectin on circulating neutrophils. However, it is unclear if this is a result of release of affected bone marrow neutrophils or if the steroid has direct effects on L-selectin expression in existing blood neutrophils. We recently demonstrated that circulating neutrophils from cattle with high blood concentrations of endogenous glucocorticoid had reduced L-selectin mRNA, suggesting that the steroid interrupted L-selectin gene expression. In the current study, dexamethasone (DEX) was administered to cattle in vivo, and blood and bone marrow neutrophils were studied simultaneously within the animal to determine which pool of cells responds to glucocorticoids with inhibited L-selectin expression. Purified blood neutrophils were also treated with DEX ± RU486 in vitro, and glucocorticoid effects on L-selectin expression were determined. Our results indicate that glucocorticoid-induced suppression of L-selectin, which accompanies neutrophilia, is likely mediated by direct effects of glucocorticoid receptor activation on intracellular reservoirs of L-selectin mRNA and protein in cattle, predominantly in blood neutrophils.
Estrogen replacement, aging, and cell-mediated immunity after injury
Authors: Kovacs Elizabeth J , Plackett Timothy P , Witte Pamela L
Published: February 2004

We recently demonstrated that aged mice are less likely to survive following traumatic injury and are more immunosuppressed than young mice who sustain comparable injuries. Immunosuppression in severely injured patients and in rodent models of burn injury is associated with a marked elevation in proinflammatory cytokines, including interleukin-6 (IL-6). We reported that after sustaining a moderate-size scald injury, aged mice have higher circulating levels of IL-6 than young, injured mice. As proestrus levels of estrogen have been reported to boost immune responses and attenuate IL-6 production, in the present study, we went on to determine if estrogen replacement in aged female mice restored cellular immunity and proinflammatory cytokine production. After injury, in placebo-treated, aged animals, there was a >75% suppression in the delayed-type hypersensitivity response relative to placebo-treated, sham-injured, aged mice (P<0.05). In contrast, estrogen supplementation before injury yielded a partial recovery in this response, such that the mice were suppressed by only 40% relative to sham-injured, aged mice (P<0.05). There was a fourfold increase in the circulating level of IL-6 in burn-injured, aged mice who received placebo hormone replacement relative to sham-injured mice given placebo (P<0.05). This level of cytokine was lowered by nearly 50% in aged, estrogen-treated mice. Most remarkably, estrogen replacement improved survival from 42% (in the absence of estrogen) to 70% in aged, burn-injured mice. Further investigation will be needed to determine if age- and gender-specific therapies are needed for the treatment of all trauma patients.
New Tumor-Node-Metastasis Staging Strategy for Node-Positive (stage III) Rectal Cancer: An Analysis
Authors: Greene Frederick L. , Stewart Andrew K. , Norton H. James
Published: February 2004

Purpose

The tumor-node-metastasis system for staging rectal cancer is based on invasion, number of involved nodes, and metastasis. Nodes are classified as N1 or N2 according to the number involved with metastases. Nodal positivity defines stage III regardless of depth of invasion or number of positive nodes. Our purpose was to analyze overall survival when node-positive patients were stratified into three new subsets.

Methods

We analyzed data entered into the National Cancer Data Base for 5,987 stage III patients with rectal cancer between 1991 and 1993. Survival was calculated using three new subgroups (IIIA: T1/2, N1; IIIB: T3/4, N1; IIIC: any T, N2). Survival following surgery and adjuvant therapy was assessed. The observed survival rates were calculated and compared using the log-rank method. The Cox regression model assessed subgroup differences.

Results

Five-year observed survival rates for stage III subcategories were 55.1% in IIIA; 35.3% in IIIB; and 24.5% in IIIC. Stratifying for treatment outcome, stage IIIA patients having surgery alone (n = 278) had poorer observed 5-year survival (39%) than patients treated with surgery and adjuvant chemotherapy or radiation therapy (chemo/XRT; n = 765; 60%). Similar outcomes occurred in IIIB (surgery-alone [n = 726; 21.7%] and chemo/XRT [n = 2,130; 40.9%] groups) and in IIIC (surgery-alone [n = 467; 12.2%] and chemo/XRT [n = 1,621; 28.9%] groups). Differences were significant (P < .0001) in all stages.

Conclusion

The traditional stage III designation of rectal cancer fails to account for invasion (T1-4) and number of involved nodes (N1, N2). The stratification of stage III patients into three subsets should be used in future analyses of rectal cancer. The effect of postoperative adjuvant therapy was beneficial in all subsets.
Cdk5 regulates axonal transport and phosphorylation of neurofilaments in cultured neurons
Authors: Shea Thomas B. , Yabe Jason T. , Ortiz Daniela , Pimenta Aurea , Loomis Patti , Goldman Robert D. , Amin Niranjana , Pant Harish C.
Published: February 2004

Phosphorylation has long been considered to regulate neurofilament (NF) interaction and axonal transport, and, in turn, to influence axonal stability and their maturation to large-caliber axons. Cdk5, a serine/threonine kinase homologous to the mitotic cyclin-dependent kinases, phosphorylates NF subunits in intact cells. In this study, we used two different haptenized NF subunits and manipulated cdk5 activity by microinjection, transfection and pharmacological inhibition to monitor the effect of Cdk5-p35 on NF dynamics and transport. We demonstrate that overexpression of cdk5 increases NF phosphorylation and inhibits NF axonal transport, whereas inhibition both reduces NF phosphorylation and enhances NF axonal transport in cultured chicken dorsal-root-ganglion neurons. Large phosphorylated-NF `bundles' were prominent in perikarya following cdk5 overexpression. These findings suggest that Cdk5-p35 activity regulates normal NF distribution and that overexpression of Cdk5-p35 induces perikaryal accumulation of phosphorylated-NFs similar to those observed under pathological conditions.
The N-myristoylated Rab-GTPase m-Rabmc is involved in post-Golgi trafficking events to the lytic vacuole in plant cells
Authors: Bolte Susanne , Brown Spencer , Satiat-Jeunemaitre Béatrice
Published: February 2004

We report on the sub-cellular localisation and function of m-Rabmc, a N-myristoylated plant-specific Rab-GTPase previously characterised at the molecular level and also by structural analysis in Mesembryanthemum crystallinum. By confocal laser scanning microscopy, we identified m-Rabmc predominantly on the prevacuolar compartment of the lytic vacuole but also on the Golgi apparatus in various plant cell types. Two complementary approaches were used immunocytochemistry and cyan fluorescent protein (CFP)/yellow fluorescent protein (YFP)-fusion proteins. Co-localisation studies of m-Rabmc with a salinity stress modulated integral calcium-ATPase suggest involvement of m-Rabmc in a plant-specific transport pathway to the prevacuolar compartment of the lytic vacuole. This hypothesis was strengthened by the inhibition of the transport of aleurain fused to green fluorescent protein (GFP), a marker of the lytic vacuole, in the presence of the dominant negative mutant m-Rabmc(N147I) in Arabidopsis thaliana protoplasts. The inhibitory effect of m-Rabmc(N147I) was specific for the transport pathway to the lytic vacuole, since the transport of chitinase-YFP, a marker for the neutral vacuole, was not hindered by the mutant.
Cascade pathway of filopodia formation downstream of SCAR
Authors: Biyasheva Assel , Svitkina Tatyana , Kunda Patricia , Baum Buzz , Borisy Gary
Published: February 2004

The protrusion of two distinct actin-containing organelles, lamellipodia and filopodia, is thought to be regulated by two parallel pathways: from Rac1 through Scar/WAVEs to lamellipodia, and from Cdc42 through N-WASP to filopodia. We tested this hypothesis in Drosophila, which contains a single gene for each WASP subfamilies, SCAR and WASp. We performed targeted depletion of SCAR or WASp by dsRNA-mediated interference in two Drosophila cultured cell lines expressing lamellipodial and filopodial protrusion. Knockdown was verified by laser capture microdissection and RT-PCR, as well as western blotting. Morphometrical, kinetic and electron microscopy analyses of the SCAR-depleted phenotype in both cell types revealed strong inhibition of lamellipodial formation and cell spreading, as expected. More importantly, filopodia formation was also strongly inhibited, which is not consistent with the parallel pathway hypothesis. By contrast, depletion of WASp did not produce any significant phenotype, except for a slight inhibition of spreading, showing that both lamellipodia and filopodia in Drosophila cells are regulated predominantly by SCAR. We propose a new, cascade pathway model of filopodia regulation in which SCAR signals to lamellipodia and then filopodia arise from lamellipodia in response to additional signal(s).
Overexpression of latent transforming growth factor-β binding protein 1 (LTBP-1) in dioxin receptor-null mouse embryo fibroblasts
Authors: Santiago-Josefat Belen , Mulero-Navarro Sonia , Dallas Sarah L. , Fernandez-Salguero Pedro M.
Published: February 2004

The aryl hydrocarbon receptor (AhR) is a transcriptional regulator of genes involved in xenobiotic metabolism. Increasingly clear is also the role of the AhR in the control of cell growth and proliferation. By analyzing differential patterns of gene expression between wild-type (AhR+/+) and null (AhR–/–) mouse embryo fibroblasts (MEF), we have identified latent transforming growth factor-β binding protein 1 (LTBP-1) as a negatively AhR-regulated gene in the absence of xenobiotics. Ltbp-1 mRNA and protein expression were markedly increased in AhR–/– MEF. Furthermore, secreted LTBP-1 was elevated in the culture medium and the extracellular matrix of AhR-null MEF. Actinomycin D inhibited Ltbp-1 mRNA overexpression, suggesting regulation at the transcriptional level. AhR activation by dioxin (TCDD) downregulated Ltbp-1, again suggesting an AhR-regulated mechanism. Treatment of AhR+/+ MEF with transforming growth factor-β(TGF-β) downregulated AhR and, simultaneously, increased Ltbp-1, further supporting the role of this receptor in LTBP-1 expression. AhR–/– conditioned medium had higher levels of active and total TGF-β activity, suggesting a role for LTBP-1 in maintaining extracellular TGF-β concentrations. TGF-β did not appear to directly regulate Ltbp-1 given that addition of TGFβ neutralizing antibody or TGFβ protein to AhR–/– MEF had no effect on Ltbp-1 expression. AhR–/– MEF had lower levels of matrix metalloproteinase 2 (MMP-2) activity, which could not be attributable to MMP-2 mRNA downregulation or MMP-inhibitors Timp-1 and Timp-2 overexpression. These data identify LTBP-1 as one of the few AhR-regulated genes not involved in xenobiotic metabolism and also support the implication of the AhR in controlling TGFβ activity and cell proliferation.
Molecular cross-talk between the transcription, translation, and nonsense-mediated decay machineries
Authors: Iborra Francisco J. , Escargueil Alexandre E. , Kwek Kon Y. , Akoulitchev Alexandre , Cook Peter R.
Published: February 2004

It is widely believed that translation occurs only in the cytoplasm of eukaryotes, but recent results suggest some takes place in nuclei, coupled to transcription. Support for this heterodoxy comes from studies of the nonsense-mediated decay (NMD) pathway; this pathway probably uses ribosomes to proofread messenger RNAs. We find components of the machineries involved in transcription, translation and NMD colocalise, interact and copurify, and that interactions between them are probably mediated by the C-terminal domain of the catalytic subunit of RNA polymerase II. These results are simply explained if the NMD machinery uses nuclear ribosomes to translate – and so proofread – newly made transcripts; then, faulty transcripts and any truncated peptides produced by nuclear translation would be degraded.
Interaction of major intrinsic protein (aquaporin-0) with fiber connexins in lens development
Authors: Yu X. Sean , Jiang Jean X.
Published: February 2004

We observed that chick lens-fiber gap-junction-forming proteins, connexin (Cx) 45.6 and Cx56, were associated with an unknown protein, which was then identified as major intrinsic protein (MIP), also known as aquaporin-0 (AQP0), the most abundant membrane protein in lens fibers. A 1063 bp cDNA of chick MIP(AQP0) was identified that encodes a 262 amino acid protein with a predicted molecular weight of 28.1 kDa. Dual immunofluorescence and confocal microscopy of sagittal and coronal sections of the lens tissues showed that MIP(AQP0) consistently localized with gap junction plaques formed by Cx45.6 and Cx56 during the early stages of embryonic chick lens development. Immunoprecipitation combined with immunoblotting analyses revealed that MIP(AQP0) was associated with Cx45.6 and Cx56 at these developmental stages. The specificity of this interaction was further confirmed with the silver staining of the protein components of immunoprecipitates. The pull-down analysis of lens lysates revealed that C-terminus of MIP(AQP0) probably interacted with these two fiber connexins. In late embryonic and adult lenses, however, uniform co-distribution of MIP(AQP0) and fiber connexins was largely disrupted, except for the area surrounding the actively differentiating bow regions, as was revealed by immunofluorescence and immunoprecipitation experiments. The interaction of MIP(AQP0) with lens fiber connexins in differentiating lens cells but not in mature lens fibers suggests a potential role for MIP(AQP0) in the facilitation of fiber connexins for the formation of gap junctions during lens development.