bluuebunny/crossref_metadata_2025 huggingface dataset:
Associations between immune parameters, parasitism, and stress in breeding pied flycatcher (Ficedula hypoleuca) females
Authors: Morales Judith , Moreno Juan , Merino Santiago , Tomás Gustavo , Martínez Javier , Garamszegi Laszlo Zsolt
Published: January 2005

There are two major interpretations of serum IgY concentration in wild birds. On the one hand, it has been considered an indication of susceptibility to stress and parasite infection. Therefore, immunoglobulin concentration is expected to change in response to variation in these factors owing to reproductive activities. On the other hand, it has been considered a measure of immune capacity. We measured the IgY level and the lymphocyte proportion at the beginning of incubation and at the end of the nestling period in female pied flycatchers, Ficedula hypoleuca (Pallas, 1764). We assessed the immune response to phytohaemagglutinin (PHA) at the latter stage. We found that the total IgY level remained constant throughout the season. Initially, it was positively associated with the PHA response, lymphocyte proportion, intensity of infection by Haemoproteus spp., and concentration of stress protein HSP70 in peripheral blood. These variables explained nearly 80% of the variation in IgY concentration. In the final phase, only the PHA response was correlated with the IgY level. We discuss the hypothetical mechanisms underlying these associations and the need to control for parasite infection and physiological stress in ecological studies including measurements of immunoglobulin concentration.
Parthenogenesis as a life strategy among mites of the suborder Uropodina (Acari: Mesostigmata)
Authors: Bloszyk J , Adamski Z , Napierala A , Dylewska M
Published: January 2005

This paper presents the results of observations concerning the phenomenon of parthenogenesis among European mites of the suborder Uropodina. An analysis of the sex ratios of 66 Polish species revealed that 18 of them (more than one fourth of the examined species) consisted only of females. The authors observed no significant relationship between geographical distribution and the lack of males in the population. Populations consisting entirely of females were observed among widely distributed species as well as among species characterized by narrow geographical ranges. Nonetheless, an increase in the number of parthenogenetic species, especially as a percentage of Middle European and Scandinavian fauna, was also discernible. Species that reproduced without males were associated with forest litter and soil, whereas bisexual species "eagerly" inhabited various relatively unstable and temporary micro environ ments (for instance, dead wood, birds' or small mammals' nests). The authors aim to define the biological role of occasionally appearing males for the species consisting almost entirely of females and discuss ecological and evolutionary aspects of parthenogenesis in mites of the suborder Uropodina.
Reproductive strategies in Akodon azarae (Rodentia, Muridae)
Authors: Suárez Olga V , Busch María , Kravetz Fernando O
Published: January 2005

The balance between litter size and the quality of offspring is a central feature to many optimal litter-size theories. We analyzed the reproductive strategies of Akodon azarae (Fischer, 1829) females, according to maternal life histories and the time of birth. Litter size decreased significantly from spring to autumn. A significant birth–season effect on mass at birth was observed. A compensatory effect of growth rate was evident during lactation. During spring and early summer, over-wintered females produced an average of 5 young, with maximum survival at weaning (100%). Females born during the current reproductive season showed a smaller litter size, probably because they favor residual reproductive value with respect to current reproduction since they have a higher life expectancy and future chances of mating than over-wintered females. Mortality reached 50% at weaning for summer litters from young mothers, whereas it declined to 22.2% in autumn. Differences in both parental investment and offspring survival suggest that litter size in A. azarae varies along the reproductive period and is dependent both on females' life history and on environmental conditions.
Reduced worker relatedness does not affect cooperation in honey bee colonies
Authors: Underwood Robyn M , Lewis Michael J , Hare James F
Published: January 2005

Although kin selection is commonly regarded as a major force in the evolution and maintenance of social behaviour in eusocial insects, recent controversy regarding whether honey bee (Apis mellifera L., 1758) workers can discriminate close kin from more distant relatives casts doubt on the extent to which cooperation among individuals within honey bee colonies is controlled by genetic relatedness. We contrasted brood and honey production in colonies where we diluted worker relatedness with those elements of productivity in colonies where relatedness was unmanipulated. Relatedness manipulation did not affect overall brood production, worker or drone brood production, the worker to drone brood sex ratio, or the volume of honey produced. Thus, there is no evidence that honey bees discriminate close from distant relatives or, more importantly, that dilution of the coefficient of relatedness within a colony has any impact on the efficiency of that colony.
A swimming activity assay shows that the thermal tolerance ofDaphnia magnais influenced by temperature acclimation
Authors: Zeis Bettina , Maurer Jana , Pinkhaus Olaf , Bongartz Eva , Paul Rüdiger J
Published: January 2005

Daphnia magna Straus, 1820 is a widespread zooplanktic organism enduring considerable changes in oxygen concentration and temperature within its natural habitat. The thermal tolerance window of D. magna was analyzed using the animals' swimming activity as a test parameter in a photometrical assay. Acclimation to different temperatures (10, 20, 30 °C) resulted in a shift of the thermal optimum corresponding to acclimation conditions. Acclimation to warm temperatures also increased the upper thermal tolerance limit in acute thermal tolerance tests. However, the magnitude of the resulting shift in the acute thermal tolerance (LT50) was much smaller. An increase in acclimation temperature by 10 °C changed the thermal optimum by approximately this value, whereas the LT50was enhanced only by 1–2 °C. The time course of the acclimation process was followed by surveying temperature-dependent swimming activity upon the transfer of animals raised in a medium at 20 °C to a medium at 30 °C. Maximum swimming intensity at 20 °C was lost within 3 days. The swimming behavior resembled that of animals acclimated to 30 °C after 2 weeks, indicating that acclimation to the elevated temperature was achieved.
Multiple paternity in socially monogamous prairie voles (Microtus ochrogaster)
Authors: Solomon Nancy G , Keane Brian , Knoch Lana R , Hogan Paula J
Published: January 2005

Prairie voles (Microtus ochrogaster (Wagner, 1842)) exhibit behavioral, morphological, and neuroendocrinological traits associated with monogamy and are considered a model system to examine the biological foundations of monogamy in mammals. We examined allelic polymorphism at microsatellite loci to assess mating exclusivity in wild prairie voles sampled in east-central Illinois and found evidence of multiple paternity in five of nine litters (56%) analyzed. Thus, a female in this socially monogamous mammal with extensive mechanisms for pair bonding does not always mate solely with its partner and raises the paradox of why some pair-bonded females mate multiply.
Genetic analysis of 16th-century whale bones prompts a revision of the impact of Basque whaling on right and bowhead whales in the western North Atlantic
Authors: Rastogi Toolika , Brown Moira W , McLeod Brenna A , Frasier Timothy R , Grenier Robert , Cumbaa Stephen L , Nadarajah Jeya , White Bradley N
Published: January 2005

The North Atlantic right whale, Eubalaena glacialis (Müller, 1776), is one of the world's most endangered large cetaceans. It is widely believed that Basque whalers caused the most dramatic decline of this species in the western North Atlantic during the early-16th and 17th centuries. Previous osteological analysis of 17 historic bones suggested that 50% of the Basque harvest consisted of right whales and 50% of bowhead whales, Balaena mysticetus L., 1758. This 50:50 ratio has been used to estimate pre-exploitation population size, which has subsequently formed the basis of recovery goals and plans for the North Atlantic right whale. Genetic analysis of 21 bones, 13 identified as right whales and 8 as bowhead whales through osteological examination, indicates that in fact only 1 bone was a right whale and 20 were bowhead whales. Additionally, preliminary microsatellite analyses of this specimen are not consistent with the hypothesis that whaling resulted in the low genetic variation found in this species today. These results differ from what would be expected based on any previous view of Basque whaling, and raise questions regarding the impact of Basque whaling on this species.
Density-dependent effects of prior residence and behavioural strategy on growth of stocked brown trout (Salmo trutta)
Authors: Brännäs Eva , Jonsson Sara , Brännäs Kurt
Published: January 2005

When animals face temporally periods of strong intraspecific competition, prior residency, available resources, and their competitive abilities in terms of size and behavioural strategy affect their chances of survival. Density, individual size, and behavioural strategy had the strongest effect on growth. The mean growth rate of both resident and intruding brown trout (Salmo trutta L., 1758) decreased with increasing density, and the largest individuals were the most successful ones independently of the density of prior residency. An aggressive behavioural factor was beneficial at the lowest and intermediate densities, whereas a nonaggressive behavioural factor was beneficial at higher densities. Prior residency had no overall significant effect on growth, as the effect was highly density-dependent. The difference in growth rate between introduced and resident individuals was significant only at high density and low food abundance per individual. The intruders had a significantly lower growth rate at high densities and fewer individuals had a high growth rate. These results suggest that stocking fish at densities exceeding the carrying capacity of the habitat results in fewer individuals that are able to compete for resources than if fewer individuals were stocked. Brood stock can then be used in a more efficient way.
LINEARIZED GRAVITY AS A GAUGE THEORY
Authors: NIETO J. A.
Published: January 2005

We discuss linearized gravity from the point of view of a gauge theory. In (3+1) dimensions our analysis allows to consider linearized gravity in the context of the MacDowell–Mansouri formalism. Our observations may be of particular interest in the strong–weak coupling duality for linearized gravity, in Randall–Sundrum brane world scenario and in Ashtekar formalism.
AN INVARIANT CHARGE MODEL FOR ALL q2>0 IN QCD AND GLUON CONDENSATE
Authors: ALEKSEEV A. I. , ARBUZOV B. A.
Published: January 2005

Under assumption of singular behavior of invariant charge αs(q2) at q2≃0 and of large q2 behavior, corresponding to the perturbation theory up to four loops, a procedure is considered of smooth matching the β-function at a boundary of perturbative and nonperturbative regions. The procedure results in a model for αs for all q2>0 with dimensionless parameters being fixed and dimensional parameters being expressed in terms of only one quantity Λ QCD . The gluon condensate which is defined by the nonperturbative part of the invariant charge is calculated for two variants of "true perturbative" invariant charge, corresponding to freezing option and to analytic one in nonperturbative region. Dimensional parameters are fixed by varying normalization condition [Formula: see text]. It is obtained that on the boundary of perturbative region [Formula: see text], the procedure results in nonperturbative Coulomb component α Coulomb ≃0.25, the nonperturbative region scale q0≃1 GeV , the model parameter σ≃(0.42 GeV )2 which suits as string tension parameter, the gluon condensate appears to be close for two variants considered, K≃(0.33–0.36 GeV )4 (for [Formula: see text]).
HYPERBOLIC RELAXATION OF THE VISCOUS CAHN–HILLIARD EQUATION IN 3-D
Authors: GATTI STEFANIA , GRASSELLI MAURIZIO , PATA VITTORINO , MIRANVILLE ALAIN
Published: January 2005

We consider a modified version of the viscous Cahn–Hilliard equation governing the relative concentration u of one component of a binary system. This equation is characterized by the presence of the additional inertial term ωutt that accounts for the relaxation of the diffusion flux. Here ω≥0 is an inertial parameter which is supposed to be dominated from above by the viscosity coefficient δ. Endowing the equation with suitable boundary conditions, we show that it generates a dissipative dynamical system acting on a certain phase-space depending on ω. This system is shown to possess a global attractor that is upper semicontinuous at ω = δ = 0. Then, we construct a family of exponential attractors εω,δ, which is a robust perturbation of an exponential attractor of the Cahn–Hilliard equation, namely the symmetric Hausdorff distance between εω,δ and ε0, 0 goes to 0 as (ω, δ) goes to (0, 0) in an explicitly controlled way. This is done by using a general theorem which requires the construction of another dynamical system, strictly related to the original one, but acting on a different phase-space depending on both ω and δ.
CONTINUOUS RAMSEY THEORY ON POLISH SPACES AND COVERING THE PLANE BY FUNCTIONS
Authors: GESCHKE STEFAN , GOLDSTERN MARTIN , KOJMAN MENACHEM
Published: January 2005

We investigate the Ramsey theory of continuous graph-structures on complete, separable metric spaces and apply the results to the problem of covering a plane by functions.

Let the homogeneity number[Formula: see text] of a pair-coloring c:[X]2→2 be the number of c-homogeneous subsets of X needed to cover X. We isolate two continuous pair-colorings on the Cantor space 2ω, c min and c max , which satisfy [Formula: see text] and prove:

Theorem. (1) For every Polish space X and every continuous pair-coloringc:[X]2→2with[Formula: see text], [Formula: see text]

(2) There is a model of set theory in which[Formula: see text]and[Formula: see text].

The consistency of [Formula: see text] and of [Formula: see text] follows from [20].

We prove that [Formula: see text] is equal to the covering number of (2ω)2 by graphs of Lipschitz functions and their reflections on the diagonal. An iteration of an optimal forcing notion associated to c min gives:

Theorem. There is a model of set theory in which

(1) ℝ2 is coverable byℵ1graphs and reflections of graphs of continuous real functions;

(2) ℝ2 is not coverable byℵ1graphs and reflections of graphs of Lipschitz real functions.

Figure 1.1 in the introduction summarizes the ZFC results in Part I of the paper. The independence results in Part II show that any two rows in Fig. 1.1 can be separated if one excludes [Formula: see text] from row (3).
DEFINABLY COMPACT ABELIAN GROUPS
Authors: EDMUNDO MÁRIO J. , OTERO MARGARITA
Published: January 2005

Let M be an o-minimal expansion of a real closed field. Let G be a definably compact definably connected abelian n-dimensional group definable in M. We show the following: the o-minimal fundamental group of G is isomorphic to ℤn; for each k>0, the k-torsion subgroup of G is isomorphic to (ℤ/kℤ)n, and the o-minimal cohomology algebra over ℚ of G is isomorphic to the exterior algebra over ℚ with n generators of degree one.
CONSTRUCTING AN ALMOST HYPERDEFINABLE GROUP
Authors: BEN-YAACOV ITAY , TOMAŠIĆ IVAN , WAGNER FRANK O.
Published: January 2005

This paper completes the proof of the group configuration theorem for simple theories started in [1]. We introduce the notion of an almost hyperdefinable (poly-)structure, and show that it has a reasonable model theory. We then construct an almost hyperdefinable group from a polygroup chunk.
Sleeve sensor versus high-resolution manometry for the detection of transient lower esophageal sphincter relaxations
Authors: Bredenoord A. J. , Weusten B. L. A. M. , Timmer R. , Smout A. J. P. M.
Published: January 2005

Transient lower esophageal sphincter relaxations (TLESRs) are the most important mechanism by which gastroesophageal reflux occurs, and sleeve sensor manometry is the gold standard for detection of TLESRs. The aim of this study was to evaluate manometry with closely spaced sideholes (high-resolution manometry) for the detection of TLESRs as an alternative. In 12 patients with gastroesophageal reflux disease, a 90-min postprandial manometry was performed by using a catheter incorporating both a sleeve sensor and closely spaced sideholes in the esophagogastric junction. TLESRs recorded with both techniques were scored. Reflux during TLESRs was detected by using manometry (common cavity), intraluminal impedance, and pH monitoring. A total of 145 TLESRs were detected by using both techniques, 117 with high-resolution manometry and 108 with sleeve sensor manometry [not significant (NS)]. Manometric signs of reflux during TLESRs detected with high-resolution and sleeve sensor manometry were found in 62.4 and 56.5%, NS, respectively, versus 38.5 and 35.2%, NS on pH-metry and 70.1 and 60.2%, NS on impedance monitoring. TLESRs recognized only with high-resolution manometry were more often accompanied by reflux, as detected with manometry (59.5%) and impedance monitoring (67.6%), than TLESRs recognized only with sleeve sensor manometry (32.1 and 28.6%). High-resolution manometry is at least as accurate as sleeve sensor manometry for the detection of TLESRs.
Blood-brain barrier integrity may be threatened by exercise in a warm environment
Authors: Watson Phillip , Shirreffs Susan M. , Maughan Ronald J.
Published: January 2005

Seven active men were recruited to examine changes in the serum concentration of S100β, a proposed peripheral marker of blood-brain barrier permeability, following prolonged exercise in temperate (T) and warm (W) conditions. Subjects were seated immersed to the neck in water at 35.0 (0.1)°C (T) or 39.0 (0.1)°C (W) for 30 min. Subjects then entered a room maintained at either 18.3 (1.8)°C (T) or 35.0 (0.3)°C (W) and completed 60 min of cycle exercise at 60% peak oxygen uptake. Serum S100β concentration was elevated after exercise in the W trial (+0.12 (0.10) μg/l; P = 0.02) but not after the T trial ( P = 0.238). Water immersion and exercise elevated core temperature by 2.1 (0.5)°C to 39.5 (0.3)°C at the end of exercise in the W trial compared with a 0.9 (0.2)°C increase during the T trial ( P < 0.001). Weighted mean skin temperature was higher throughout the W trial compared with the T trial ( P < 0.001). Heart rate ( P < 0.001) and blood glucose ( P < 0.001) and lactate ( P < 0.001) concentrations were elevated to a greater extent during exercise in the W trial than in the T trial. Ratings of perceived exertion ( P < 0.001) and thermal comfort ( P < 0.001) were markedly higher throughout the W trial than in the T trial. The results of this study demonstrate that serum S100β was elevated after water immersion and prolonged exercise in a warm environment, suggesting that blood-brain barrier permeability may be altered.
Greater free plasma VEGF and lower soluble VEGF receptor-1 in acute mountain sickness
Authors: Tissot van Patot Martha C. , Leadbetter Guy , Keyes Linda E. , Bendrick-Peart Jamie , Beckey Virginia E. , Christians Uwe , Hackett Peter
Published: January 2005

Vascular endothelial growth factor (VEGF) is a hypoxia-induced protein that produces vascular permeability, and limited evidence suggests a possible role for VEGF in the pathophysiology of acute mountain sickness (AMS) and/or high-altitude cerebral edema (HACE). Previous studies demonstrated that plasma VEGF alone does not correlate with AMS; however, soluble VEGF receptor (sFlt-1), not accounted for in previous studies, can bind VEGF in the circulation, reducing VEGF activity. In the present study, we hypothesized that free VEGF is greater and sFlt-1 less in subjects with AMS compared with well individuals at high altitude. Subjects were exposed to 4,300 m for 19–20 h (baseline 1,600 m). The incidence of AMS was determined by using a modified Lake Louise symptom score and the Environmental Symptoms Questionnaire for cerebral effects. Plasma was collected at low altitude and after 24 h at high altitude, or at time of illness, and then analyzed by ELISA for VEGF and for soluble VEGF receptor, sFlt-1. AMS subjects had lower sFlt-1 at both low and high altitude compared with well subjects and a significant rise in free plasma VEGF on ascent to altitude compared with well subjects. We conclude that increased free plasma VEGF on ascent to altitude is associated with AMS and may play a role in pathophysiology of AMS.
Nociceptin in rVLM mediates electroacupuncture inhibition of cardiovascular reflex excitatory response in rats
Authors: Crisostomo Melissa M. , Li Peng , Tjen-A-Looi Stephanie C. , Longhurst John C.
Published: January 2005

Electroacupuncture (EA) at Neiguan-Jianshi acupoints through an opioid mechanism inhibits the cardiovascular pressor response induced by mechanical stimulation of the stomach. Because nociceptin also may regulate cardiovascular activity through its action in the brain stem, we hypothesized that this neuromodulator serves a role in the EA-related inhibitory effect. Blood pressure in ventilated male Sprague-Dawley rats (400–600 g) anesthetized by ketamine and α-chloralose was measured during balloon inflation of the stomach. Gastric distension with 6–8 ml of air induced consistent pressor reflexes of 26 ± 1 mmHg that could be repeated every 10 min for 100 min. When nociceptin (10 nM) was microinjected into the rostral ventrolateral medulla (rVLM), the pressor response induced by gastric distension was inhibited by 68 ± 6%. Thirty minutes of EA also decreased the reflex response by 75 ± 11%; microinjection of saline into the rVLM did not alter the inhibitory effect of EA. In contrast, microinjection of a nociceptin receptor antagonist into the rVLM promptly reversed the EA response. Pretreatment with the opioid receptor antagonist naloxone did not influence the EA-like inhibitory effect of nociceptin on the distension-induced pressor reflex (22 ± 1 to 8 ± 2 mmHg). Furthermore, a μ-opioid receptor agonist microinjected into the rVLM after microinjection of a nociceptin receptor antagonist during EA promptly reversed the nociceptin receptor antagonist-related inhibition of the EA effect. Thus, in addition to the classical opioid system, nociceptin, through opioid receptor-like-1 receptor stimulation in the rVLM, participates in the modulatory influence of EA on reflex-induced increases in blood pressure.
Biophysical and Morphological Properties of Parasympathetic Neurons Controling the Parotid and von Ebner Salivary Glands in Rats
Authors: Fukami Hideyuki , Bradley Robert M.
Published: January 2005

The inferior salivatory nucleus (ISN) contains parasympathetic neurons controlling the parotid and von Ebner salivary glands. To characterize the neurophysiological and morphological properties of these neurons, intracellular recordings were made from anatomically identified ISN neurons in rat brain slices. Neurons were also filled with Lucifer yellow and morphometrically analyzed. Based on responses to membrane hyperpolarization followed by depolarization, three types of repetitive discharge patterns were defined for neurons innervating the parotid gland. The regular, repetitive discharge response to membrane depolarization was changed by hyperpolarization resulting either in a delay in the occurrence of the first spike or to an increase in the length of the first interspike interval in the action potential train. Membrane hyperpolarization had little effect on the discharge pattern of some neurons. Similar response discharge patterns were found for neurons innervating the von Ebner salivary gland, which also included a further group of neurons that responded with a short burst of action potentials. Neurons innervating the parotid salivary glands differed morphologically from the von Ebner salivary glands having significantly larger soma and more and longer dendrites than von Ebner gland neurons. In addition, the mean membrane input resistance, time constant, and spike half-width of parotid gland neurons was significantly lower than in von Ebner gland neurons. These differences in intrinsic membrane properties and morphology may relate to the functions of the von Ebner and parotid glands. von Ebner glands are involved in taste stimulus delivery and removal from posterior tongue papillae while the parotid glands contribute saliva to the entire mouth.
Endothelial Progenitor Cells for Vasculogenesis
Authors: Murasawa Satoshi , Asahara Takayuki
Published: January 2005

Postnatal vasculogenesis is considered to be involved in neovascularization of adult tissues, because bone marrow-derived endothelial progenitor cells (EPCs) were isolated from circulating mononuclear cells in peripheral blood and were shown to incorporate into sites of physiological and pathological neovascularization and to differentiate into mature endothelial cells. EPCs might have an attractive potential therapeutic application for cardiovascular ischemic diseases as a novel cell-based strategy mainly via a vasculogenesis mechanism.
High Glucose Induces Human Endothelial Cell Apoptosis Through a Phosphoinositide 3-Kinase–Regulated Cyclooxygenase-2 Pathway
Authors: Sheu Meei Ling , Ho Feng Ming , Yang Rong Sen , Chao Kuo Fang , Lin Wan Wan , Lin-Shiau Shoei Yn , Liu Shing-Hwa
Published: January 2005

Objectives—

Diabetes mellitus causes endothelial dysfunction. The precise molecular mechanisms by which hyperglycemia causes apoptosis in endothelial cells are not yet well understood. The aim of this study was to explore the role of cyclooxygenase-2 (COX-2) and the possible involvement of phosphoinositide 3-kinase (PI3K) signaling in high glucose (HG)–induced apoptosis in human umbilical vein endothelial cells (HUVECs).

Methods and Results—

For detection of apoptosis, the morphological Hoechst staining and Annexin V/propidium iodide staining were used. Glucose upregulated COX-2 protein expression, which was associated with the induction of prostaglandin (PG) E
2
(PGE
2
), caspase-3 activity, and apoptosis. Unexpectedly, we found that PI3K inhibitors could suppress COX-2 expression, PGE
2
production, caspase-3 activity, and the subsequent apoptosis under HG condition. Glucose-induced activation of PI3K resulted in the downstream effector Akt phosphorylation. PI3K inhibitors effectively attenuated the intracellular reactive oxygen species (ROS) generation and nuclear factor κB (NF-κB) activation. Blocking the PI3K and Akt activities with the dominant-negative vectors greatly diminished the HG-triggered NF-κB activation and COX-2 expression and apoptosis.

Conclusions—

These results suggest that HG, via PI3K/Akt signaling, induces NF-κB–related upregulation of COX-2, which in turn triggers the caspase-3 activity that facilitates HUVEC apoptosis. Also, HG may cause ROS generation in HUVECs through a PI3K/Akt–dependent pathway.
Nod1-Mediated Endothelial Cell Activation by
Chlamydophila pneumoniae
Authors: Opitz Bastian , Förster Stefanie , Hocke Andreas C. , Maass Matthias , Schmeck Bernd , Hippenstiel Stefan , Suttorp Norbert , Krüll Matthias
Published: January 2005

Seroepidemiological and animal studies, as well as demonstration of viable bacteria in atherosclerotic plaques, have linked
Chlamydophila pneumoniae
infection to development of chronic vascular lesions and coronary heart disease. Inflammation and immune responses are dependent on host recognition of invading pathogens. The recently identified cytosolic Nod proteins are candidates for intracellular recognition of bacteria, such as the obligate intracellular chlamydia. In the present study, mechanisms of endothelial cell activation by
C
.
pneumoniae
via Nod proteins were examined. Viable, but not heat-inactivated, chlamydia activated human endothelial cells, suggesting that invasion of these cells is necessary for their profound activation. Endothelial cells express Nod1. Nod1 gene silencing by small interfering RNA reduced
C pneumoniae
–induced IL-8 release markedly. Moreover, in HEK293 cells, overexpressed Nod1 or Nod2 amplified the capacity of
C pneumoniae
to induce nuclear factor κB (NF-κB) activation. Interestingly, heat-inactivated bacteria were still able to induced a NF-κB reporter gene activity via Nod proteins when transfected intracellularly, but not when provided from the extracellular side. In contrast, TLR2 sensed extracellular heat-inactivated chlamydia. In conclusion, we demonstrated that
C pneumoniae
induced a Nod1-mediated and Nod2-mediated NF-κB activation in HEK293 cells. In endothelial cells, Nod1 played a dominant role in triggering a chlamydia-mediated inflammatory process.
Extending the Role of Associative Learning Processes in Nicotine Addiction
Authors: Bevins Rick A. , Palmatier Matthew I.
Published: January 2005

Compulsive smoking is a worldwide public health problem. Although research has confirmed the importance of associative learning processes in nicotine addiction, therapies targeting nicotine-associated cues still have a high relapse rate. Most theories conceptualize nicotine as an ‘outcome’ that reinforces behaviors and/or changes the affective value of stimuli. Albeit important, this view does not capture the complexity of associative processes involved in nicotine addiction. For example, nicotine serves as a conditional stimulus acquiring new appetitive/affective properties when paired with a non-drug reward. Also, nicotine functions as an occasion setter that participates in higher-order associative processes that likely permit a more pervasive influence of conditioned cues that are resistant to typically cue-exposure therapy techniques. Finally, nicotine appears to amplify the salience of other stimuli that have some incentive value resulting in enhanced nicotine selfadministration and conditioned reinforcement processes. Future smoking intervention strategies should take into consideration these additional associative learning processes.
Tumor necrosis factor-α–dependent expression of phosphodiesterase 2: role in endothelial hyperpermeability
Authors: Seybold Joachim , Thomas Dirk , Witzenrath Martin , Boral Şengül , Hocke Andreas C. , Bürger Alexander , Hatzelmann Armin , Tenor Hermann , Schudt Christian , Krüll Matthias , Schütte Hartwig , Hippenstiel Stefan , Suttorp Norbert
Published: January 2005

The pleiotropic cytokine tumor necrosis factor-α (TNF-α) and thrombin lead to increased endothelial permeability in sepsis. Numerous studies demonstrated the significance of intracellular cyclic nucleotides for the maintenance of endothelial barrier function. Actions of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) are terminated by distinct cyclic nucleotide phosphodiesterases (PDEs). We hypothesized that TNF-α could regulate PDE activity in endothelial cells, thereby impairing endothelial barrier function. In cultured human umbilical vein endothelial cells (HUVECs), we found a dramatic increase of PDE2 activity following TNF-α stimulation, while PDE3 and PDE4 activities remained unchanged. Significant PDE activities other than PDE2, PDE3, and PDE4 were not detected. TNF-α increased PDE2 expression in a p38 mitogen-activated protein kinase (MAPK)–dependent manner. Endothelial barrier function was investigated in HUVECs and in isolated mice lungs. Selective PDE2 up-regulation sensitized HUVECs toward the permeability-increasing agent thrombin. In isolated mice lungs, we demonstrated that PDE2 inhibition was effective in preventing thrombin-induced lung edema, as shown with a reduction in both lung wet-to-dry ratio and albumin flux from the vascular to bronchoalveolar compartment. Our findings suggest that TNF-α–mediated up-regulation of PDE2 may destabilize endothelial barrier function in sepsis. Inhibition of PDE2 is therefore of potential therapeutic interest in sepsis and acute respiratory distress syndrome (ARDS).
Flt3 tandem duplication mutations cooperate with Wnt signaling in leukemic signal transduction
Authors: Tickenbrock Lara , Schwäble Joachim , Wiedehage Markus , Steffen Björn , Sargin Bülent , Choudhary Chunaram , Brandts Christian , Berdel Wolfgang E. , Müller-Tidow Carsten , Serve Hubert
Published: January 2005

Activating Flt3 mutations occur in about 30% of patients with acute myeloid leukemia (AML), often as in-frame internal tandem duplication (ITD) at the juxtamembrane domain of the receptor. These mutations transform hematopoietic cell lines and primary mouse bone marrow. Here, we analyzed the interaction between oncogenic Flt3-ITD mutations and the Wingless-type (Wnt) signaling pathway in the myeloid progenitor cell line 32D. Microarray analyses revealed higher mRNA expression of Frizzled-4, a receptor for Wnt ligands in 32D/Flt3-ITD cells. Findings were verified by quantitative realtime reverse transcription–polymerase chain reaction (RT-PCR) and on the protein level. Compared with 32D/Flt3-WT (wild-type) cells, 32D/Flt3-ITD cells also showed greatly enhanced β-catenin protein levels, irrespective of their exposure to Wnt3a, a ligand inducing the canonical Wnt signal transduction pathway. In addition, 5 of 7 AML samples with Flt3-ITD mutations expressed high β-catenin protein levels, whereas patients with wild-type Flt3 did not. Also, Flt3-ITD induced enhanced T-cell factor (TCF)–dependent transcriptional activity and the induction of the Wnt target gene c-myc. In the presence of Flt3-WT or Flt3-ITD signaling, Wnt3a slightly increased 32D cell proliferation. However, transfection experiments with dominant-negative (dn) TCF4 revealed a strong dependence of Flt3-ITD–mediated clonogenic growth on TCF activity. Taken together, our results indicate that Flt3-ITD and Wnt-dependent signaling pathways synergize in myeloid transformation.
The threshold of gp130-dependent STAT3 signaling is critical for normal regulation of hematopoiesis
Authors: Jenkins Brendan J. , Roberts Andrew W. , Najdovska Meri , Grail Dianne , Ernst Matthias
Published: January 2005

The interleukin-6 (IL-6) cytokine family plays an important role in regulating cellular responses during hematopoiesis. We report here that mice homozygous for a knock-in mutation in the IL-6 cytokine family receptor signaling subunit glycoprotein (gp) 130 (gp130Y757F/Y757F) that leads to gp130-dependent signal transducers and activators of transcription (STAT) 1/3 hyperactivation develop a broad spectrum of hematopoietic abnormalities, including splenomegaly, lymphadenopathy, and thrombocytosis. To determine whether STAT3 hyperactivation was responsible for the perturbed hematopoiesis in gp130Y757F/Y757F mice, we generated gp130Y757F/Y757F mice on a Stat3 heterozygous (Stat3+/-) background to specifically reduce gp130-dependent activation of STAT3, but not STAT1. Normal hematopoiesis was observed in gp130Y757F/Y757F:Stat3+/- bone marrow and spleen, with no evidence of the splenomegaly and thrombocytosis displayed by gp130Y757F/Y757F mice. The perturbed cellular composition of thymus and lymph nodes in gp130Y757F/Y757F mice was also alleviated in gp130Y757F/Y757F: Stat3+/- mice. Furthermore, we show that hematopoietic cells from gp130Y757F/Y757F mice exhibited increased survival and proliferation in response to IL-6 family cytokines. Collectively, these data provide genetic evidence that gp130-dependent STAT3 hyperactivation during hematopoiesis has pathological consequences affecting multiple organs, and therefore identify the threshold of STAT3 signaling elicited by IL-6 family cytokines as a critical determinant for hematopoietic homeostasis.
Cyclic nucleotide binding proteins in the Arabidopsis thaliana and Oryza sativa genomes
Authors: Bridges Dave , Fraser Marie E , Moorhead Greg BG
Published: January 2005

Background

Cyclic nucleotides are ubiquitous intracellular messengers. Until recently, the roles of cyclic nucleotides in plant cells have proven difficult to uncover. With an understanding of the protein domains which can bind cyclic nucleotides (CNB and GAF domains) we scanned the completed genomes of the higher plants Arabidopsis thaliana (mustard weed) and Oryza sativa (rice) for the effectors of these signalling molecules.

Results

Our analysis found that several ion channels and a class of thioesterases constitute the possible cyclic nucleotide binding proteins in plants. Contrary to some reports, we found no biochemical or bioinformatic evidence for a plant cyclic nucleotide regulated protein kinase, suggesting that cyclic nucleotide functions in plants have evolved differently than in mammals.

Conclusion

This paper provides a molecular framework for the discussion of cyclic nucleotide function in plants, and resolves a longstanding debate about the presence of a cyclic nucleotide dependent kinase in plants.
The association of spatial T wave axis deviation with incident coronary events. The ARIC cohort
Authors: Vaidean Georgeta D , Rautaharju Pentti M , Prineas Ronald J , Whitsel Eric A , Chambless Lloyd E , Folsom Aaron R , Rosamond Wayne D , Zhang Zhu-Ming , Crow Richard S , Heiss Gerardo
Published: January 2005

Background

Although current evidence suggests that the spatial T wave axis captures important information about ventricular repolarization abnormalities, there are only a few and discordant epidemiologic studies addressing the ability of the spatial T wave axis to predict coronary heart disease (CHD) occurrence.

Methods

This prospective study analyzed data from 12,256 middle-aged African American and white men and women, from the Atherosclerosis Risk in Communities Study (ARIC). Following a standardized protocol, resting standard 12-lead, 10-second electrocardiograms were digitized and analyzed with the Marquette GE program. The median follow-up time was 12.1 years; incident coronary heart disease comprised fatal and non-fatal CHD events.

Results

The incidence rate of CHD was 4.26, 4.18, 4.28 and 5.62 per 1000 person-years respectively, across the spatial T wave axis quartiles. Among women for every 10 degrees increase in the spatial T wave axis deviation, there was an estimated increase in the risk of CHD of 1.16 (95% CI 1.04–1.28). After adjustment for age, height, weight, smoking, hypertension, diabetes, QRS axis and minor T wave abnormalities, this hazard rate ratio for women fell to 1.03 (0.92–1.14). The corresponding crude and adjusted hazard ratios for men were 1.05 (95% CI 0.96–1.15) and 0.95 (0.86–1.04) respectively.

Conclusions

In conclusion, this prospective, population-based, bi-ethnic study of men and women free of coronary heart disease at baseline shows that spatial T wave axis deviation is not associated with incident coronary events during long-term follow up. It is doubtful that spatial T wave axis deviation would add benefit in the prediction of CHD events above and beyond the current traditional risk factors.
Psychological distress among Bam earthquake survivors in Iran: a population-based study
Authors: Montazeri Ali , Baradaran Hamid , Omidvari Sepideh , Azin Seyed Ali , Ebadi Mehdi , Garmaroudi Gholamreza , Harirchi Amir Mahmood , Shariati Mohammad
Published: January 2005

Background

An earthquake measuring 6.3 on the Richter scale struck the city of Bam in Iran on the 26th of December 2003 at 5.26 A.M. It was devastating, and left over 40,000 dead and around 30,000 injured. The profound tragedy of thousands killed has caused emotional and psychological trauma for tens of thousands of people who have survived. A study was carried out to assess psychological distress among Bam earthquake survivors and factors associated with severe mental health in those who survived the tragedy.

Methods

This was a population-based study measuring psychological distress among the survivors of Bam earthquake in Iran. Using a multi-stage stratified sampling method a random sample of individuals aged 15 years and over living in Bam were interviewed. Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12).

Results

In all 916 survivors were interviewed. The mean age of the respondents was 32.9 years (SD = 12.4), mostly were males (53%), married (66%) and had secondary school education (50%). Forty-one percent reported they lost 3 to 5 members of their family in the earthquake. In addition the findings showed that 58% of the respondents suffered from severe mental health as measured by the GHQ-12 and this was three times higher than reported psychological distress among the general population. There were significant differences between sub-groups of the study sample with regard to their psychological distress. The results of the logistic regression analysis also indicated that female gender; lower education, unemployment, and loss of family members were associated with severe psychological distress among earthquake victims.

Conclusion

The study findings indicated that the amount of psychological distress among earthquake survivors was high and there is an urgent need to deliver mental health care to disaster victims in local medical settings and to reduce negative health impacts of the earthquake adequate psychological counseling is needed for those who survived the tragedy.
Arthritis imaging using a near-infrared fluorescence folate-targeted probe
Authors: Chen Wei-Tsung , Mahmood Umar , Weissleder Ralph , Tung Ching-Hsuan
Published: January 2005

A recently developed near-infrared fluorescence-labeled folate probe (NIR2-folate) was tested for in vivo imaging of arthritis using a lipopolysaccharide intra-articular injection model and a KRN transgenic mice serum induction mouse model. In the lipopolysaccharide injection model, the fluorescence signal intensity of NIR2-folate (n = 12) and of free NIR2 (n = 5) was compared between lipopolysaccharide-treated and control joints. The fluorescence signal intensity of the NIR2-folate probe at the inflammatory joints was found to be significantly higher than the control normal joints (up to 2.3-fold, P < 0.001). The NIR2-free dye injection group showed a persistent lower enhancement ratio than the NIR2-folate probe injection group. Excessive folic acid was also given to demonstrate a competitive effect with the NIR2-folate. In the KRN serum transfer model (n = 4), NIR2-folate was applied at different time points after serum transfer, and the inflamed joints could be detected as early as 30 hours after arthritogenic antibody transfer (1.8-fold increase in signal intensity). Fluorescence microscopy, histology, and immunohistochemistry validated the optical imaging results. We conclude that in vivo arthritis detection was feasible using a folate-targeted near-infrared fluorescence probe. This receptor-targeted imaging method may facilitate improved arthritis diagnosis and early assessment of the disease progress by providing an in vivo characterization of active macrophage status in inflammatory joint diseases.
Accelerated evolution associated with genome reduction in a free-living prokaryote
Authors: Dufresne Alexis , Garczarek Laurence , Partensky Frédéric
Published: January 2005

Background

Three complete genomes of Prochlorococcus species, the smallest and most abundant photosynthetic organism in the ocean, have recently been published. Comparative genome analyses reveal that genome shrinkage has occurred within this genus, associated with a sharp reduction in G+C content. As all examples of genome reduction characterized so far have been restricted to endosymbionts or pathogens, with a host-dependent lifestyle, the observed genome reduction in Prochlorococcus is the first documented example of such a process in a free-living organism.

Results

Our results clearly indicate that genome reduction has been accompanied by an increased rate of protein evolution in P. marinus SS120 that is even more pronounced in P. marinus MED4. This acceleration has affected every functional category of protein-coding genes. In contrast, the 16S rRNA gene seems to have evolved clock-like in this genus. We observed that MED4 and SS120 have lost several DNA-repair genes, the absence of which could be related to the mutational bias and the acceleration of amino-acid substitution.

Conclusions

We have examined the evolutionary mechanisms involved in this process, which are different from those known from host-dependent organisms. Indeed, most substitutions that have occurred in Prochlorococcus have to be selectively neutral, as the large size of populations imposes low genetic drift and strong purifying selection. We assume that the major driving force behind genome reduction within the Prochlorococcus radiation has been a selective process favoring the adaptation of this organism to its environment. A scenario is proposed for genome evolution in this genus.
An ontology for cell types
Authors: Bard Jonathan , Rhee Seung Y , Ashburner Michael
Published: January 2005

We describe an ontology for cell types that covers the prokaryotic, fungal, animal and plant worlds. It includes over 680 cell types. These cell types are classified under several generic categories and are organized as a directed acyclic graph. The ontology is available in the formats adopted by the Open Biological Ontologies umbrella and is designed to be used in the context of model organism genome and other biological databases. The ontology is freely available at http://obo.sourceforge.net/ and can be viewed using standard ontology visualization tools such as OBO-Edit and COBrA.
Predictive Validity of the Implicit Association Test in Studies of Brands, Consumer Attitudes, and Behavior
Authors: Maison Dominika , Greenwald Anthony G. , Bruin Ralph H.
Published: January 2005

Three studies investigated implicit brand attitudes and their relation to explicit attitudes, product usage, and product differentiation. Implicit attitudes were measured using the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998). Study 1 showed expected differences in implicit attitudes between users of two leading yogurt brands, also revealing significant correlations between IAT‐measured implicit attitudes and explicit attitudes. In Study 2, users of two fast food restaurants (McDonald's and Milk Bar) showed implicit attitudi‐nal preference for their favorite restaurant. In Study 3, implicit attitudes of users of two soft drinks (Coca‐Cola and Pepsi) predicted brand preference, product usage, and brand recognition in a blind taste test. A meta‐analytic combination of the three studies showed that the use of IAT measures increased the prediction of behavior relative to explicit attitude measures alone.
Evil Is More Than Banal: Situationism and the Concept of Evil
Authors: Berkowitz Leonard
Published: January 2005

Social psychology as a discipline has given relatively little attention to the problem of evil in society, and those discussions in this field that do exist typically regard evil actions as only varieties of aggression without any characteristics that distinguish them from other forms of intentional mistreatment of others. Because of the field's situationistic perspective emphasizing the individual's susceptibility to the power of the immediate situation, social psychologists generally view the fairly high levels of obedience to authority displayed in Milgram's (1963, 1974) classic experiment as the paradigmatic example of evil behavior. For them, much evil is, in Arendt's (1963) well-known phrase, only “banal,” and Milgram's findings are often viewed as illustrating the “central dynamic” involved in the slaughter of millions of Jews and other “undesirables” in the Holocaust. This article holds that Milgram's (1974) obedience research does not represent significant features of the Holocaust, especially the sadism that occurred not infrequently, and disregards the vital difference between those who initiated the murderous policy and the others who followed their orders. Building on Darley's (1992) earlier conjectures about the features that ordinary people might consider in judging whether any given action is evil, I suggest that many persons have a prototypic conception of evil and speculate about the dimensions that could be involved in this prototype.