bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing Sequence Variation in the Receptor-Targeting Domain of Feline Leukemia Virus Envelope Proteins with Peptide Display Libraries
Authors: Bupp Keith , Sarangi Anindita , Roth Monica J.
Published: January 2005

Determinants of cellular tropism and receptor targeting lie within a short peptide in the Vr1 region of the envelope (Env) proteins of feline leukemia virus (FeLV) subgroups A and C. Libraries of FeLV Env proteins with random amino acid substitutions in the peptide were screened for their ability to deliver a marker gene to D17 and AH927 cells. Screening on D17 canine cells yielded D17-specific Env proteins that used the FeLV-C receptor. Screening on AH927 cells yielded Env proteins with a broader host range, with maximal titers on AH927 cells and similar or lower titers on other cells. These Env proteins used an unidentified non-FeLV receptor for entry. The A5 isolate obtained from the AH927 screen was readily concentrated to yield titers of 10
5
on human PC-3 prostate tumor cells. The sequence divergence observed among targeting peptides of library-selected Env proteins was greater than that found in parental FeLV isolates. Substitution analyses of a conserved R in the middle of the targeting peptide held constant during screening indicated that maximal titers were obtained only when R was present in both a D17 selected isolate and an AH927 selected isolate. The ability to isolate Env proteins with unique tropisms dependent on the cells on which the library is screened has direct implications for targeting gene delivery vectors.
Hepatitis C Virus (HCV) Constitutively Activates STAT-3 via Oxidative Stress: Role of STAT-3 in HCV Replication
Authors: Waris Gulam , Turkson James , Hassanein Tarek , Siddiqui Aleem
Published: January 2005

The hepatitis C virus (HCV) causes chronic hepatitis, which often results in liver cirrhosis and hepatocellular carcinoma. We have previously shown that HCV nonstructural proteins induce activation of STAT-3 via oxidative stress and Ca
2+
signaling (G. Gong, G. Waris, R. Tanveer, and A. Siddiqui, Proc. Natl. Acad. Sci. USA
98:
9599-9604, 2001). In this study, we focus on the signaling pathway leading to STAT-3 activation in response to oxidative stress induced by HCV translation and replication activities. Here, we demonstrate the constitutive activation of STAT-3 in HCV replicon-expressing cells. The HCV-induced STAT-3 activation was inhibited in the presence of antioxidant (pyrrolidine dithiocarbamate) and Ca
2+
chelators (BAPTA-AM and TMB-8). Previous studies have shown that maximum STAT-3 transactivation requires Ser727 phosphorylation in addition to tyrosine phosphorylation. Using a series of inhibitors and dominant negative mutants, we show that HCV-induced activation of STAT-3 is mediated by oxidative stress and influenced by the activation of cellular kinases, including p38 mitogen-activated protein kinase, JNK, JAK-2, and Src. Our results also suggest a potential role of STAT-3 in HCV RNA replication. We also observed the constitutive activation of STAT-3 in the liver biopsy of an HCV-infected patient. These studies provide an insight into the mechanisms by which HCV induces intracellular events relevant to liver pathogenesis associated with the viral infection.
Contribution of Virus-Like Particles to the Immunogenicity of Human Immunodeficiency Virus Type 1 Gag-Derived Vaccines in Mice
Authors: Wong S. B. Justin , Siliciano Robert F.
Published: January 2005

The human immunodeficiency virus type 1 (HIV-1) Gag protein is a major target antigen for cytotoxic-T-lymphocyte-based vaccine strategies because of its high level of conservation. The murine model has been used extensively to evaluate potential HIV-1 vaccines. However, the biology of HIV-1 Gag is somewhat different in human and murine tissues. The ability of HIV-1 Gag to form virus-like particles (VLPs) in human cells is severely curtailed in murine cells. Hence, it is not known whether immunizing mice with expression vectors encoding HIV-1 Gag provides an accurate assessment of the immunogenicity of these candidate vaccines in primates. In this report, we made use of a chimeric Moloney murine leukemia virus (MMLV)-HIV-1 Gag in which the p17 matrix domain of HIV-1 was replaced with the p15 matrix and p12 domains from MMLV. Murine cells expressing this construct released significant amounts of VLPs. The construct preservedH-2d-restricted antigenic determinants in the remaining portion of HIV-1 Gag, allowing immunogenicity studies to be performed with mice. We demonstrated that immunizing mice with plasmid DNA or adenoviral vectors encoding this chimeric Gag did not significantly increase the HIV-1 Gag-specific cellular or humoral immune response when compared to immunization with a myristoylation-incompetent version of the construct. Thus, the release of VLPs formed in vivo may not play a major role in the immunogenicity of vectors expressing HIV-1 Gag constructs.
Characterization of gp120 and Its Single-Chain Derivatives, gp120-CD4D12and gp120-M9: Implications for Targeting the CD4iEpitope in Human Immunodeficiency Virus Vaccine Design
Authors: Varadarajan Raghavan , Sharma Deepak , Chakraborty Kausik , Patel Mayuri , Citron Michael , Sinha Prem , Yadav Ramkishor , Rashid Umar , Kennedy Sarah , Eckert Debra , Geleziunas Romas , Bramhill David , Schleif William , Liang Xiaoping , Shiver John
Published: January 2005

Single-chain derivatives of JRFL gp120 linked to the first two domains of human CD4 (gp120-CD4D12) or to the CD4 miniprotein analog CD4M9 (gp120-M9), have been constructed. Biacore studies revealed that gp120-CD4D12and gp120-M9 bound to antibody 17b with dissociation constants of 0.8 and 25 nM, respectively, at pH 7.0, while gp120 alone did not bind. The binding of gp120-CD4D12to 17b is not affected by the addition of excess soluble CD4D12, while the binding of gp120-M9 is enhanced. This finding indicates that the M9 component of the single chain interacts relatively weakly with gp120 and can be displaced by soluble CD4D12. Immunogenicity studies of gp120, gp120-CD4D12, and gp120-M9 were carried out with guinea pigs. All three molecules were highly immunogenic. The resulting antisera were examined for neutralizing activities against various human immunodeficiency virus type 1 isolates. Broadly neutralizing activity was observed only with sera generated against gp120-CD4D12. These antisera were depleted of anti-CD4D12antibodies by being passed over a column containing immobilized CD4D12. The depleted sera showed a loss of broadly neutralizing activity. Sera that were affinity purified over a column containing immobilized gp120-M9 also lacked such neutralizing activity. This finding suggests that the broadly neutralizing response observed is exclusively due to anti-CD4 antibodies. Competition experiments showed that only antisera generated against gp120-CD4D12competed with the CD4iantibody 17b and that this activity was not affected by depletion of anti-CD4 antibodies. The data indicate that although antibodies targeting the CD4iepitope were generated by the gp120-CD4D12immunogen, these antibodies were nonneutralizing.
The Epstein-Barr Virus-Encoded LMP2A and LMP2B Proteins Promote Epithelial Cell Spreading and Motility
Authors: Allen Michael D. , Young Lawrence S. , Dawson Christopher W.
Published: January 2005

The frequent expression of latent membrane proteins LMP2A and LMP2B in Epstein Barr virus (EBV)-associated tumors suggests that these proteins play a role in EBV-induced epithelial cell growth transformation. Expression of LMP2A and LMP2B had no effect on the morphology of squamous epithelial cells in monolayer culture, but their expression was associated with an increased capacity to spread and migrate on extracellular matrix. Although the mechanisms by which LMP2A and LMP2B promote cell spreading and motility are unclear, the use of selective pharmacological inhibitors has established a role for tyrosine kinases in this phenotype but ruled out contributions of phosphatidylinositol 3-kinase, extracellular signal-regulated kinase/mitogen-activated protein kinase, and protein kinase C. The ability of LMP2B to induce a phenotype that is virtually indistinguishable from that of LMP2A suggests that regions of the LMP2 protein in addition to the cytosolic amino terminus are capable of inducing phenotypic effects in epithelial cells. Thus, rather than serving to modulate the activity of LMP2A, LMP2B may directly engage signaling pathways to influence epithelial cell behavior such as cell adhesion and motility.
VP40 Octamers Are Essential for Ebola Virus Replication
Authors: Hoenen Thomas , Volchkov Viktor , Kolesnikova Larissa , Mittler Eva , Timmins Joanna , Ottmann Michelle , Reynard Olivier , Becker Stephan , Weissenhorn Winfried
Published: January 2005

Matrix protein VP40 of Ebola virus is essential for virus assembly and budding. Monomeric VP40 can oligomerize in vitro into RNA binding octamers, and the crystal structure of octameric VP40 has revealed that residues Phe125 and Arg134 are the most important residues for the coordination of a short single-stranded RNA. Here we show that full-length wild-type VP40 octamers bind RNA upon HEK 293 cell expression. While the Phe125-to-Ala mutation resulted in reduced RNA binding, the Arg134-to-Ala mutation completely abolished RNA binding and thus octamer formation. The absence of octamer formation, however, does not affect virus-like particle (VLP) formation, as the VLPs generated from the expression of wild-type VP40 and mutated VP40 in HEK 293 cells showed similar morphology and abundance and no significant difference in size. These results strongly indicate that octameric VP40 is dispensable for VLP formation. The cellular localization of mutant VP40 was different from that of wild-type VP40. While wild-type VP40 was present in small patches predominantly at the plasma membrane, the octamer-negative mutants were found in larger aggregates at the periphery of the cell and in the perinuclear region. We next introduced the Arg134-to-Ala and/or the Phe125-to-Ala mutation into the Ebola virus genome. Recombinant wild-type virus and virus expressing the VP40 Phe125-to-Ala mutation were both rescued. In contrast, no recombinant virus expressing the VP40 Arg134-to-Ala mutation could be recovered. These results suggest that RNA binding of VP40 and therefore octamer formation are essential for the Ebola virus life cycle.
Productive Interaction between Transmembrane Mutants of the Bovine Papillomavirus E5 Protein and the Platelet-Derived Growth Factor β Receptor
Authors: Lai Char-Chang , Edwards Anne P. B. , DiMaio Daniel
Published: January 2005

The bovine papillomavirus E5 protein is a 44-amino-acid transmembrane protein that transforms cells by binding to the transmembrane region of the cellular platelet-derived growth factor (PDGF) β receptor, resulting in sustained receptor signaling. However, there are published reports that certain mutants with amino acid substitutions in the membrane-spanning segment of the E5 protein transform cells without activating the PDGF β receptor. We re-examined several of these transmembrane mutants, and here we present five lines of evidence that these mutants do in fact activate the PDGF β receptor, resulting in cellular signaling and transformation.
The Predominant Mechanism by Which Ribavirin Exerts Its Antiviral Activity In Vitro against Flaviviruses and Paramyxoviruses Is Mediated by Inhibition of IMP Dehydrogenase
Authors: Leyssen Pieter , Balzarini Jan , De Clercq Erik , Neyts Johan
Published: January 2005

It is not yet clear to what extent depletion of intracellular GTP pools contributes to the antiviral activity of ribavirin. Therefore, the antiviral activities of (i) ribavirin, (ii) its 5-ethynyl analogue, 5-ethynyl-1-β-
d
-ribofuranosylimidazole-4-carboxamide (EICAR), and (iii) mycophenolic acid (MPA) (a compound that inhibits only cellular IMP dehydrogenase activity) were studied on the replication of flaviviruses and paramyxoviruses. In addition, the effects of these three compounds on intracellular GTP pools were assessed. A linear correlation was observed over a broad concentration range between the antiviral activities of ribavirin, EICAR, and MPA and the effects of these compounds on GTP pool depletion. When the 50% effective concentrations (EC
50
s) for the antiviral activities of ribavirin, EICAR, and MPA were plotted against the respective EC
50
values for GTP pool depletion, a linear correlation was calculated. These data provide compelling evidence that the predominant mechanism of action of ribavirin in vitro against flavi- and paramyxoviruses is based on inhibition of cellular IMP dehydrogenase activity.
Bovine Herpesvirus 1 VP22 Enhances the Efficacy of a DNA Vaccine in Cattle
Authors: Zheng Chunfu , Babiuk Lorne A. , van Drunen Littel-van den Hurk Sylvia
Published: January 2005

For this study, the intercellular trafficking ability of bovine herpesvirus 1 (BHV-1) VP22 was applied to improve the efficacy of a DNA vaccine in calves. A plasmid encoding a truncated version of glycoprotein D (tgD) fused to VP22 was constructed. The plasmid encoding tgD-VP22 elicited significantly enhanced and more balanced immune responses than those induced by a plasmid encoding tgD. Furthermore, protection against a BHV-1 challenge was obtained in calves immunized with the plasmid encoding tgD-VP22, as shown by significant reductions in viral excretion. However, less significant protection was observed for animals vaccinated with the tgD-expressing plasmid, correlating with the lower level of immunity observed prechallenge. This is the first report of the use of VP22 as a transport molecule in the context of a DNA vaccine for a large animal species.
Vaccination with an Inactivated Virulent Feline Immunodeficiency Virus Engineered To Express High Levels of Env
Authors: Hosie Margaret J. , Klein Dieter , Binley James Μ. , Dunsford Thomas H. , Jarrett Oswald , Neil James C. , Knapp Elzbieta , Giannecchini Simone , Matteucci Donatella , Bendinelli Mauro , Hoxie James A. , Willett Brian J.
Published: January 2005

An inactivated virus vaccine was prepared from a pathogenic isolate of feline immunodeficiency virus containing a mutation that eliminated an endocytic sorting signal in the envelope glycoprotein, increasing its expression on virions. Cats immunized with inactivated preparations of this modified virus exhibited strong titers of antibody to Env by enzyme-linked immunosorbent assay. Evidence of protection following challenge demonstrated the potential of this approach to lentiviral vaccination.
A case record of electroosmotic consolidation of soft clay with improved soilelectrode contact
Authors: Burnotte Fabien , Lefebvre Guy , Grondin Gilles
Published: January 2005

Electroosmotic (e.o.) consolidation of clays has been known in geotechnical engineering for many decades but is in fact seldom used. The analysis of published data from case records indicates that the power losses at the soilelectrode contact constitute a major problem for the field application of e.o. consolidation. A laboratory study, where field conditions were reproduced, has demonstrated the efficiency of a chemical treatment at the electrodes to enhance potential transfer to soil. The chemical treatment was evaluated in a large field demonstration test where over 700 m3of clay was consolidated by electroosmosis. The paper describes the site, the field setup, and the results and analysis of the monitoring during the 48 days of the e.o. treatment. The results of the post-treatment geotechnical investigation after 12% of clay compression due to electroosmotic consolidation are also presented and discussed. These results confirm that soft clay deposits can be successfully treated by e.o. consolidation, at a competitive cost compared with other alternatives, when power losses at the soilelectrode contact are controlled.Key words: case record, electroosmosis, soft clays, consolidation, soil improvement.
Measurement of pile load transfer using the Fiber Bragg Grating sensor system
Authors: Lee Woojin , Lee Won-Je , Lee Sang-Bae , Salgado Rodrigo
Published: January 2005

A series of laboratory and field tests were performed to evaluate the applicability of an optical fiber sensor system in the instrumentation of piles. A multiplexed sensor system, constructed by arranging several Fiber Bragg Grating (FBG) sensors along a single line of optical fiber, is capable of measuring local axial strains as a function of wavelength shifts. The distributions of axial load in three model piles and a field test pile evaluated from the strains measured by FBG sensors are found to be comparable, in terms of both magnitude and trend, with those obtained from conventional strain gauges. This suggests that the FBG sensor system is an effective tool for the analysis of the axial load transfer in piles. The successful instrumentation of a soilcement injected precast (SIP) pile using FBG sensors suggests that the use of these sensors in drilled shafts and other types of cast in situ concrete piles is feasible. With the rapid advance of optical fiber sensor technology, the economics of the use of optical fiber sensors in this type of instrumentation is expected to improve significantly in coming years.Key words: pile foundation, load transfer, fiber optic sensor, Fiber Bragg Grating sensor.
Mechanical behavior of compacted composite clays
Authors: Jafari M K , Shafiee A
Published: January 2005

Composite clay is a mixture of clay, as the main body, and aggregates, which are floating within the clayey matrix. The undrained behavior of composite clay in its natural or compacted state, e.g., core material of embankment dams, has great importance for geotechnical engineers. An extensive test program was conducted on kaolingravel and kaolinsand mixtures to investigate various effects of aggregates on the mechanical behavior of the mixtures during strain-controlled monotonic and cyclic loadings. Monotonic test results reveal that increasing the aggregate content leads to a gradual increase in shear strength. Meanwhile, when the aggregate content is raised, the pore pressure increases for both monotonic and cyclic loading. It is also found that the presence of aggregates within a cohesive matrix leads to formation of a heterogeneous matrix in the clayey part of composite clays. This heterogeneity in turn causes pore pressure to be increased with an increase in the aggregate content during both monotonic and cyclic loading. In addition, test results show that aggregate size does not influence mechanical behavior appreciably. The results of this experimental research program are presented and discussed in this paper.Key words: composite clay, aggregate, shear strength, pore pressure, heterogeneous matrix, embankment dam.
Design methods for geosynthetic anchor trenches on the basis of true scale experiments and discrete element modelling
Authors: Villard Pascal , Chareyre Bruno
Published: January 2005

Analytical models are proposed for analysing the mechanisms whereby geosynthetic anchors fail. The cases of run-out and L- or V-shaped anchor trenches are considered. An analytical expression is obtained for the tension that may be mobilized in the anchor as a function of the geometry and mechanical properties of the materials. Two hypotheses relating to the nature of the soil are taken into account, assuming failure either through relative slippage between the soil and the inclusion (cohesive soil) or by deformation of the anchoring soil mass (frictional soil). The proposed analytical formulations are compared with the numerical results of discrete-element simulations and with the experimental results of full-scale pullout tests. The results obtained show the validity of the proposed analytical formulations for designing anchors in trenches.Key words: geosynthetics, anchorage, pullout, design, failure, discrete elements.
SPECTRA OF RELIC GRAVITONS AND BRANS–DICKE THEORY
Authors: SAHOO B. K.
Published: January 2005

The spectra of relic gravitational waves produced as a result of cosmological expansion of the inflationary models are derived in Brans–Dicke (BD) theory of gravity. The time dependence of the very early Hubble parameter and matter energy density are derived from frequency-dependent spectrum of relic gravitational waves. Also it is found that Brans–Dicke scalar field contributes to the energy density of relic gravitons.
Pavlovian Conditioning: A Functional Perspective
Authors: Domjan Michael
Published: January 2005

From a functional perspective, Pavlovian conditioning involves learning about conditioned stimuli (CSs) that have a pre-existing relation to an unconditioned stimulus (US) rather than learning about arbitrary or neutral CSs. In addition, the most important product of learning involves changes in how the organism responds to the US, not in how it responds to the CS, because the US is the more biologically relevant stimulus. These concepts are illustrated using examples from a variety of behavioral and physiological situations including caloric intake and digestion, breast feeding, poison-avoidance learning, eyeblink conditioning, sexual conditioning, fear conditioning, aggression, and drug tolerance and sensitization.
Subsarcolemmal and intermyofibrillar mitochondria play distinct roles in regulating skeletal muscle fatty acid metabolism
Authors: Koves Timothy R. , Noland Robert C. , Bates Andrew L. , Henes Sarah T. , Muoio Deborah M. , Cortright Ronald N.
Published: January 2005

Skeletal muscle contains two populations of mitochondria that appear to be differentially affected by disease and exercise training. It remains unclear how these mitochondrial subpopulations contribute to fiber type-related and/or training-induced changes in fatty acid oxidation and regulation of carnitine palmitoyltransferase-1β (CPT1β), the enzyme that controls mitochondrial fatty acid uptake in skeletal muscle. To this end, we found that fatty acid oxidation rates were 8.9-fold higher in subsarcolemmal mitochondria (SS) and 5.3-fold higher in intermyofibrillar mitochondria (IMF) that were isolated from red gastrocnemius (RG) compared with white gastrocnemius (WG) muscle, respectively. Malonyl-CoA (10 μM), a potent inhibitor of CPT1β, completely abolished fatty acid oxidation in SS and IMF mitochondria from WG, whereas oxidation rates in the corresponding fractions from RG were inhibited only 89% and 60%, respectively. Endurance training also elicited mitochondrial adaptations that resulted in enhanced fatty acid oxidation capacity. Ten weeks of treadmill running differentially increased palmitate oxidation rates 100% and 46% in SS and IMF mitochondria, respectively. In SS mitochondria, elevated fatty acid oxidation rates were accompanied by a 48% increase in citrate synthase activity but no change in CPT1 activity. Nonlinear regression analyses of mitochondrial fatty acid oxidation rates in the presence of 0–100 μM malonyl-CoA indicated that IC50 values were neither dependent on mitochondrial subpopulation nor affected by exercise training. However, in IMF mitochondria, training reduced the Hill coefficient ( P < 0.05), suggesting altered CPT1β kinetics. These results demonstrate that endurance exercise provokes subpopulation-specific changes in mitochondrial function that are characterized by enhanced fatty acid oxidation and modified CPT1β-malonyl-CoA dynamics.
CD63 interacts with the carboxy terminus of the colonic H+-K+-ATPase to increase plasma membrane localization and 86Rb+ uptake
Authors: Codina Juan , Li Jian , DuBose Thomas D.
Published: January 2005

The carboxy terminus (CT) of the colonic H+-K+-ATPase is required for stable assembly with the β-subunit, translocation to the plasma membrane, and efficient function of the transporter. To identify protein-protein interactions involved in the localization and function of HKα2, we selected 84 amino acids in the CT of the α-subunit of mouse colonic H+-K+-ATPase (CT-HKα2) as the bait in a yeast two-hybrid screen of a mouse kidney cDNA library. The longest identified clone was CD63. To characterize the interaction of CT-HKα2 with CD63, recombinant CT-HKα2 and CD63 were synthesized in vitro and incubated, and complexes were immunoprecipitated. CT-HKα2 protein (but not CT-HKα1) coprecipitated with CD63, confirming stable assembly of HKα2 with CD63. In HEK-293 transfected with HKα2 plus β1-Na+-K+-ATPase, suppression of CD63 by RNA interference increased cell surface expression of HKα2/NKβ1 and 86Rb+ uptake. These studies demonstrate that CD63 participates in the regulation of the abundance of the HKα2-NKβ1 complex in the cell membrane.
Phenotype analysis of aquaporin-8 null mice
Authors: Yang Baoxue , Song Yuanlin , Zhao Dan , Verkman A. S.
Published: January 2005

Aquaporin-8 (AQP8) is a water-transporting protein expressed in organs of the mammalian gastrointestinal tract (salivary gland, liver, pancreas, small intestine, and colon) and in the testes, heart, kidney, and airways. We studied the phenotype of AQP8-null mice, and mice lacking AQP8, together with AQP1 or AQP5. AQP8-knockout mice lacked detectable AQP8 transcript and protein, and had reduced water permeability in plasma membranes from testes. Breeding of AQP8 heterozygous mice yielded AQP8-null mice, whose number, survival, and growth were not different from those of wild-type mice. Organ weight and serum/urine chemistries were similar in wild-type and AQP8-null mice, except for increased testicular weight in the null mice (4.8 ± 0.7 vs. 7.3 ± 0.3 mg/g body wt). Urinary concentrating ability in AQP8-null mice was unimpaired as assessed by urine osmolality (3,590 ± 360 mosmol/kgH2O) and weight loss (22 ± 2%) after 36-h water deprivation; urinary concentrating ability was similarly impaired in AQP1-null mice vs. AQP8/AQP1 double-knockout mice. Agonist-driven fluid secretion in salivary gland was not different in AQP8 vs. wild-type mice (∼1 μl·min−1·g body wt−1) or in AQP5-null mice vs. AQP8/AQP5 double-knockout mice. Closed intestinal loop measurements in vivo indicated unimpaired osmotically driven water transport, active fluid absorption, and cholera toxin-driven fluid secretion in AQP8-null mice. After 21 days on a 50% fat diet, wild-type and AQP8-null mice had similar weight gain (∼15 g), with no evidence of steatorrhea or abnormalities in blood chemistries, except for mild hypertriglyceridemia in the null mice. The mild phenotype of AQP8-null mice was surprising in view of the multiple phenotype abnormalities found in mouse models of AQP1–5 deficiency.
Physiological Basis for Novel Drug Therapies Used to Treat the Inflammatory Bowel Diseases I. Immunology and therapeutic potential of antiadhesion molecule therapy in inflammatory bowel disease
Authors: Van Assche Gert , Rutgeerts Paul
Published: January 2005

Adhesion molecules regulate the influx of leukocytes in normal and inflamed gut. They are also involved in local lymphocyte stimulation and antigen presentation within the intestinal mucosa. In intestinal inflammation, many adhesion molecules are upregulated, but α4-integrins most likely hold a key position in directing leukocytes into the inflamed bowel wall. Therapeutic compounds directed against trafficking of leukocytes have been designed and are being developed as a novel class of drugs in the treatment of Crohn's disease and ulcerative colitis. This review deals with the immunological aspects of leukocyte trafficking focused on gut homing of T cells. Second, the changes in adhesion molecules and T cell trafficking during intestinal inflammation are discussed. Finally, we review the clinical data that have been gathered with respect to the therapeutic potential and the safety of antiadhesion molecule treatment. Antegren, or natalizumab, a humanized anti-α4integrin IgG4antibody, has been most extensively evaluated and may be close to registration. A more specific humanized α4β7-integrin MLN-02 has shown preliminary clinical efficacy in ulcerative colitis, and both antergren and MLN-02 appear to be very safe. Trials with the anti-ICAM-1 antisense oligonucleotide ISIS-2302 in steroid refractory Crohn's disease have provided conflicting efficacy data. In the near future, some of these novel biological agents may prove valuable therapeutic tools in the management of refractory inflammatory bowel disease, although it is too early to define the patient population that will benefit most from these agents.
Heterogeneous effects of tissue inhibitors of matrix metalloproteinases on cardiac fibroblasts
Authors: Lovelock Joshua D. , Baker Andrew H. , Gao Feng , Dong Jing-Fei , Bergeron Angela L. , McPheat Willie , Sivasubramanian Natarajan , Mann Douglas L.
Published: January 2005

The balance between matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), plays a critical role in cardiac remodeling. Although a number of studies have characterized the pathophysiological role of MMPs in the heart, very little is known with respect to the role of TIMPs in the heart. To delineate the role of TIMPs in the heart we examined the effects of adenovirus-mediated overexpression of TIMP-1, -2, -3, and -4 in cardiac fibroblasts. Infection of cardiac fibroblasts with adenoviral constructs containing human recombinant TIMP (AdTIMP-1, -2, -3, and -4) provoked a significant ( P < 0.0001) 1.3-fold in increase in bromodeoxyuridine (BrdU) incorporation. Similarly, treatment of cardiac fibroblasts with AdTIMP-1-, -2-, -3-, and -4-conditioned medium led to a 1.2-fold increase in BrdU incorporation ( P < 0.0001) that was abolished by pretreatment with anti-TIMP-1, -2, -3, and -4 antibodies. The effects of TIMPs were not mimicked by treating the cells with RS-130830, a broad-based MMP inhibitor, suggesting that the effects of TIMPs were independent of their ability to inhibit MMPs. Infection with AdTIMP-1, -2, -3, and -4 led to a significant increase in α-smooth muscle actin staining, consistent with TIMP-induced phenotypic differentiation into myofibroblasts. Finally, infection with AdTIMP-2 resulted in a significant increase in collagen synthesis, whereas infection with AdTIMP-3 resulted in a significant increase in fibroblast apoptosis. TIMPs exert overlapping as well as diverse effects on isolated cardiac fibroblasts. The observation that TIMPs stimulate fibroblast proliferation as well as phenotypic differentiation into myofibroblasts suggests that TIMPs may play an important role in tissue repair in the heart that extends beyond their traditional role as MMP inhibitors.
Aggregate formation of erythrocytes in postcapillary venules
Authors: Kim Sangho , Popel Aleksander S. , Intaglietta Marcos , Johnson Paul C.
Published: January 2005

The purpose of the present study was to obtain information on erythrocyte aggregate formation in vivo. The movements of erythrocytes in postcapillary venules of the rat spinotrapezius muscle at various flow rates were recorded with a high-speed video camera before and after infusion of dextran 500. To distinguish aggregates, the following criteria were used: 1) a fixed distance (4 μm) between the center points of two adjacent cells, 2) lack of visible separation between the adjacent cells, and 3) movement of the adjacent cells in the same direction. Without dextran 500 infusion, 11 and 5% of erythrocytes formed aggregates in low (33.2 ± 28.3 s) and high pseudoshear (144.2 ± 58.3 s) conditions, respectively, based on the above criteria. After dextran 500 infusion, 53% of erythrocytes satisfied the criteria in the low pseudoshear condition (26.5 ± 17.0 s) and 13% of erythrocytes met the criteria in the high pseudoshear condition (240.0 ± 85.9 s), indicating erythrocyte aggregation is strongly associated with shear rate. Approximately 90% of aggregate formation occurred in a short time period (0.15–0.30 s after entering the venule) in a region 15 to 30 μm from the entrance. The time delay may reflect rheological entrance conditions in the venule.
Pharmacological stimulation of cardiac gap junction coupling does not affect ischemia-induced focal ventricular tachycardia or triggered activity in dogs
Authors: Xing Dezhi , Kjølbye Anne Louise , Petersen Jørgen S. , Martins James B.
Published: January 2005

The role of gap junction intercellular communication (GJIC) in ischemia-induced focal ventricular tachycardia (VT) is unknown. We have developed a new, stable antiarrhythmic peptide analog named ZP123 that selectively increases GJIC and prevents reentrant VT. Our aim in this study was to use ZP123 as a tool to assess the role of GJIC on occurrence of ischemia-induced focal VT and triggered activity (TA) due to delayed afterdepolarizations (DADs). Focal VT was induced by programmed stimulation in α-chloralose-anesthetized, open-chest dogs 1–4 h after coronary artery occlusion. Three-dimensional activation mapping was done using 6 bipolar electrograms on each of 23 multipolar needles in the risk zone. Dogs were randomly assigned to receive either saline or ZP123 cumulatively at three dose levels (an intravenous bolus followed by a 30-min infusion per dose). Attempts to induce VT were repeated in each dose. Mass spectrometry was used to measure plasma ZP123 concentrations. Standard microelectrode techniques were used for in vitro study of DADs and TA. Twenty-six dogs with focal VT were included. ZP123 did not affect the inducibility of focal VT at any plasma concentrations vs. saline (0.8 ± 0.1 nM, 77 vs. 75%; 7.8 ± 0.4 nM, 86 vs. 77%; and 78.8 ± 5.0 nM, 77 vs. 91%). In vitro, ZP123 did not affect the induction of DADs (12/12) and TAs (10/10) in ischemic tissues or tissue removed from the origin of focal VT (DADs, 8/8; TAs, 4/4). Therefore, although indirect, the data with the doses and concentrations used suggest that GJIC may not play a major role in the genesis of focal activity in the ischemic models studied.
Contribution of the subfornical organ to angiotensin II-induced hypertension
Authors: Hendel Michael D. , Collister John P.
Published: January 2005

Previous studies clearly demonstrated acute actions of angiotensin II (ANG II) at one of the central circumventricular organs, the subfornical organ (SFO), but studies demonstrating a role for the SFO in the chronic actions of ANG II remain uncertain. The purpose of this study was to examine the role of the SFO in the chronic hypertensive phase of ANG II-induced hypertension. We hypothesized that the SFO is necessary for the full hypertensive response observed during the chronic phase of ANG II-induced hypertension. To test this hypothesis, male Sprague-Dawley rats were subjected to sham operation (sham rats) or electrolytic lesion of the SFO (SFOx rats). After 1 wk, the rats were instrumented with venous catheters and radiotelemetric transducers for intravenous administration of ANG II and measurement of blood pressure and heart rate, respectively. Rats were then allowed 1 wk for recovery. After 3 days of saline control infusion (7 ml of 0.9% NaCl/day), sham and SFOx rats were infused with ANG II at 10 ng·kg−1·min−1 iv for 10 consecutive days and then allowed to recover for 3 days. A 0.4% NaCl diet and distilled water were provided ad libitum. At day 5 of ANG II infusion, mean arterial pressure increased 11.7 ± 3.0 mmHg in sham rats ( n = 9) but increased only 3.7 ± 1.4 mmHg in SFOx rats ( n = 9). This trend continued through day 10 of ANG II treatment. These results support the hypothesis that the SFO is necessary for the full hypertensive response to chronic ANG II administration.
Acute Vagotomy Activates the Cholinergic Anti-Inflammatory Pathway
Authors: van Westerloo David , van der Poll Tom
Published: January 2005

Within minutes of acute myocardial infarction (MI), proinflammatory cytokines increase in the brain, heart, and plasma. We hypothesized that cardiac afferent nerves stimulated by myocardial injury signal the brain to increase central cytokines. Urethane-anesthetized male Sprague-Dawley rats underwent ligation of the left anterior descending coronary artery (LAD) or sham LAD ligation after bilateral cervical vagotomy, sham vagotomy, or application of a 10% phenol solution to the epicardial surface of the myocardium at risk. MI caused a significant increase in tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the plasma and heart, which was blunted by vagotomy. MI also caused a significant increase in hypothalamic TNF-α and IL-1β, which was not affected by vagotomy. In contrast, epicardial phenol blocked MI-induced increases in hypothalamic TNF-α and IL-1β without affecting increases in the plasma and heart. These findings demonstrate that the appearance of proinflammatory cytokines in the brain after MI is independent of blood-borne cytokines and suggest that cardiac sympathetic afferent nerves activated by myocardial ischemia signal the brain to increase cytokine production. In addition, an intact vagus nerve is required for the full expression of proinflammatory cytokines in the injured myocardium and in the circulation. We conclude that the sympathetic and parasympathetic innervation of the heart both contribute to the acute proinflammatory response to MI.
Increased salt appetite in patients with congenital adrenal hyperplasia 21-hydroxylase deficiency
Authors: Kochli A. , Tenenbaum-Rakover Y. , Leshem M.
Published: January 2005

Salt appetite was investigated in 14 patients with congenital adrenal hyperplasia of the salt-wasting form (SW group), 12 patients with the simple virilized form who are not salt losing, and 18 healthy siblings. Salt appetite was evaluated by questionnaire, preference tests, and dietary analyses. The findings showed that SW who were not therapeutically normalized showed increased salt appetite but no change in sweet preference. Their salt appetite correlated with symptoms of salt wasting, namely, plasma renin activity, plasma K+, and urine Na+ and (inversely) with blood pressure. Sensitivity to the taste of NaCl was not altered. Factor analyses of a larger group confirmed the distinction between salt appetite and sweet preference, but intake of dietary Na+ and sweet carbohydrates and intake of salty and sweet snacks did not reflect distinct salt or sweet preferences. We confirm that putative perinatal dehydration, due to maternal nausea and vomiting during pregnancy, childhood vomiting, and diarrhea with occasional saline infusion, was related to increased salt appetite in adolescence. The findings suggest that salt appetite in humans is determined by interdependent, innate, physiological, and acquired attributes. Salt appetite in SW patients is an adaptive response mediated by the renin-angiotensin system, an innate predisposition to acquire salt preference (in anticipation of both sodium loss and its consequence), and imprinting by perinatal hyponatremic occurrences. Our findings contribute to understanding human salt intake, provide insight into the motivation for salt in patients with congenital adrenal hyperplasia 21-OH deficiency, and may point the way to improvements in therapeutic compliance in these patients.
A restrospective perspective
Authors: Gamble John
Published: January 2005

Venous occlusion plethysmography is a simple but elegant technique that has contributed to almost every major area of vascular biology in humans. The general principles of plethysmography were appreciated by the late 1800s, and the application of these principles to measure limb blood flow occurred in the early 1900s. Plethysmography has been instrumental in studying the role of the autonomic nervous system in regulating limb blood flow in humans and important in studying the vasodilator responses to exercise, reactive hyperemia, body heating, and mental stress. It has also been the technique of choice to study how human blood vessels respond to a variety of exogenously administered vasodilators and vasoconstrictors, especially those that act on various autonomic and adrenergic receptors. In recent years, plethysmography has been exploited to study the role of the vascular endothelium in health and disease. Venous occlusion plethysmography is likely to continue to play an important role as investigators seek to understand the physiological significance of newly identified vasoactive factors and how genetic polymorphisms affect the cardiovascular system in humans.
Pulmonary and extrapulmonary acute lung injury: inflammatory and ultrastructural analyses
Authors: Menezes Sara L. S. , Bozza Patricia T. , Faria Neto Hugo C. Castro , Laranjeira Andrea P. , Negri Elnara M. , Capelozzi Vera L. , Zin Walter A. , Rocco Patricia R. M.
Published: January 2005

To test whether pulmonary and extrapulmonary acute lung injury (ALI) of identical mechanical compromise would express diverse morphological patterns and immunological pathways. For this purpose, a model of pulmonary (p) and extrapulmonary (exp) ALI with similar functional changes was developed and pulmonary morphology (light and electron microscopy), cytokines levels, and neutrophilic infiltration in the bronchoalveolar lavage fluid (BALF), elastic and collagen fiber content in the alveolar septa, and neutrophil apoptosis in the lung parenchyma were analyzed. BALB/c mice were divided into four groups. In control groups, saline was intratracheally (it, 0.05 ml) instilled and intraperitoneally (ip, 0.5 ml) injected, respectively. In the ALIp and ALIexp groups, mice received E. coli lipopolysaccharide (10 μg it and 125 μg ip, respectively). The changes in lung resistive and viscoelastic pressures and in static elastance, alveolar collapse, and cell content in lung tissue were similar in the ALIp and ALIexp groups. The ALIp group presented a threefold increase in KC (murine function homolog to IL-8) and IL-10 levels in the BALF in relation to ALIexp, whereas IL-6 level showed a twofold increase in ALIp. Neutrophils in the BALF were more frequent in ALIp than in ALIexp. ALIp showed more extensive injury of alveolar epithelium, intact capillary endothelium, and apoptotic neutrophils, whereas the ALIexp group presented interstitial edema and intact type I and II cells and endothelial layer. In conclusion, given the same pulmonary mechanical dysfunction independently of the etiology of ALI, insult in pulmonary epithelium yielded more pronounced inflammatory responses, which induce ultrastructural morphological changes.
Varicosity-Schwann Cell Interactions Mediated by ATP in the Mouse Vas Deferens
Authors: Lin Y. Q. , Bennett M. R.
Published: January 2005

Schwann cells, from a variety of sources, are known to possess P2Y purinergic metabotropic receptors. However, it is not known if Schwann cells associated with autonomic nerve terminals possess such receptors and if so whether these receptors are activated by the endogenous release of ATP from the nerve terminals. We show that such Schwann cells in the vas deferens give evoked calcium transients on nerve stimulation. These transients are mediated, at least in part, by the endogenous release of ATP, which acts on Schwann cell P2Y receptors to release calcium from within the cells. This work suggests the possibility that Schwann cells are active participants in the process of junctional transmission in the autonomic nervous system.
Kinematic and EMG Determinants in Quadrupedal Locomotion of a Non-Human Primate (Rhesus)
Authors: Courtine Grégoire , Roy Roland R. , Hodgson John , McKay Heather , Raven Joseph , Zhong Hui , Yang Hong , Tuszynski Mark H. , Edgerton V. Reggie
Published: January 2005

We hypothesized that the activation patterns of flexor and extensor muscles and the resulting kinematics of the forelimbs and hindlimbs during locomotion in the Rhesus would have unique characteristics relative to other quadrupedal mammals. Adaptations of limb movements and in motor pool recruitment patterns in accommodating a range of treadmill speeds similar to other terrestrial animals in both the hindlimb and forelimb were observed. Flexor and extensor motor neurons from motor pools in the lumbar segments, however, were more highly coordinated than in the cervical segments. Unlike the lateral sequence characterizing subprimate quadrupedal locomotion, non-human primates use diagonal coordination between the hindlimbs and forelimbs, similar to that observed in humans between the legs and arms. Although there was a high level of coordination between hind- and forelimb locomotion kinematics, limb-specific neural control strategies were evident in the intersegmental coordination patterns and limb endpoint trajectories. Based on limb kinematics and muscle recruitment patterns, it appears that the hindlimbs, and notably the distal extremities, contribute more to body propulsion than the forelimbs. Furthermore, we found adaptive changes in the recruitment patterns of distal muscles in the hind- and forelimb with increased treadmill speed that likely correlate with the anatomical and functional evolution of hand and foot digits in monkeys. Changes in the properties of both the spinal and supraspinal circuitry related to stepping, probably account for the peculiarities in the kinematic and EMG properties during non-human primate locomotion. We suggest that such adaptive changes may have facilitated evolution toward bipedal locomotion.
Utilidad de Ortega y Gasset para la actual psicología social
Authors: Ovejero Anastasio
Published: January 2005

Hoy día, exactamente a medio siglo de la muerte del filósofo José Ortega y Gasset, el interés de su obra y de su pensamiento para la psicología y para la psicología social es no sólo grande, sino incluso mucho mayor aunque en el pasado, a causa fundamentalmente de la profunda crisis en que está actualmente inmerso el paradigma positivista en todas las ciencias sociales, incluidas las psicológicas. Como sabemos, el fracaso del positivismo en las ciencias sociales y humanas está llevando a propuestas abiertamente postpositivistas, de tal manera que se está volviendo la vista hacia autores en otra época alejados de los intereses de los psicólogos (Nietzsche, Husserl, Heidegger, etcétera), autores entre los que indefectiblemente debemos situar a Ortega y Gasset. Pues bien, ése es justamente el principal objetivo de este artículo: mostrar la utilidad de Ortega para los psicólogos sociales de hoy día, sobre la base de que la psicología española de este recién estrenado siglo XXI ganaría mucho si se apropiara de las principales reflexiones del filósofo madrileño, reflexiones abierta y explícitamente postpositivistas.
La ruptura de contrato psicológico entre los soldados profesionales españoles y su relación con la decisión de permanecer o abandonar
Authors: Topa Gabriela , Palací J.-Francisco
Published: January 2005

El marco teórico de la construcción de sentido por los recién llegados a la organización es el punto de partida de este estudio, que examina los factores asociados con los cambios en las percepciones de los contratos psicológicos durante el proceso de socialización. Más en concreto, hipotetizamos que la decisión de permanecer o abandonar la organización será función de la ruptura de contrato percibida medida durante el período de entrenamiento. Además, hipotetizamos que los resultados actitudinales y conductuales autoinformados serán función de la ruptura de contrato medida dos años antes, durante el período de entrenamiento. Para poner a prueba estas hipótesis se realizó un estudio longitudinal con dos momentos de recogida de datos de 556 soldados profesionales de nueva incorporación. Los datos proporcionan apoyo parcial a las hipótesis y abren nuevas vías de teorización e investigación.