bluuebunny/crossref_metadata_2025 huggingface dataset:
Genomic and Morphological Features of a Banchine Polydnavirus: Comparison with Bracoviruses and Ichnoviruses
Authors: Lapointe Renée , Tanaka Kohjiro , Barney Walter E. , Whitfield James B. , Banks Jonathan C. , Béliveau Catherine , Stoltz Don , Webb Bruce A. , Cusson Michel
Published: April 2007

Many ichneumonid and braconid endoparasitoids inject a polydnavirus (PDV) into their caterpillar hosts during oviposition. The viral entities carried by wasps of these families are referred to as “ichnoviruses” (IVs) and “bracoviruses” (BVs), respectively. All IV genomes characterized to date are found in wasps of the subfamily Campopleginae; consequently, little is known about PDVs found in wasps of the subfamily Banchinae, the only other ichneumonid taxon thus far shown to carry these viruses. Here we report on the genome sequence and virion morphology of a PDV carried by the banchine parasitoid
Glypta fumiferanae
. With an aggregate genome size of ∼290 kb and 105 genome segments, this virus displays a degree of genome segmentation far greater than that reported for BVs or IVs. The size range of its genome segments is also lower than those in the latter two groups. As reported for other PDVs, the predicted open reading frames of this virus cluster into gene families, including the protein tyrosine phosphatase (PTP) and viral ankyrin (
ank
) families, but phylogenetic analysis indicates that
ank
genes of the
G. fumiferanae
virus are not embedded within the IV lineage, while its PTPs and those of BVs form distinct clusters. The banchine PDV genome also encodes a novel family of NTPase-like proteins displaying a pox-D5 domain. The unique genomic features of the first banchine virus examined, along with the morphological singularities of its virions (IV-like nucleocapsids, but enveloped in groups like some of the BVs), suggest that they could have an origin distinct from those of IVs and BVs.
Binding Dynamics of Hepatitis C Virus' NS5A Amphipathic Peptide to Cell and Model Membranes
Authors: Cho Nam-Joon , Cheong Kwang Ho , Lee ChoongHo , Frank Curtis W. , Glenn Jeffrey S.
Published: April 2007

Membrane association of the hepatitis C virus NS5A protein is required for viral replication. This association is dependent on an N-terminal amphipathic helix (AH) within NS5A and is restricted to a subset of host cell intracellular membranes. The mechanism underlying this specificity is not known, but it may suggest a novel strategy for developing specific antiviral therapy. Here we have probed the mechanistic details of NS5A AH-mediated binding to both cell-derived and model membranes by use of biochemical membrane flotation and quartz crystal microbalance (QCM) with dissipation. With both assays, we observed AH-mediated binding to model lipid bilayers. When cell-derived membranes were coated on the quartz nanosensor, however, significantly more binding was detected, and the QCM-derived kinetic measurements suggested the existence of an interacting receptor in the target membranes. Biochemical flotation assays performed with trypsin-treated cell-derived membranes exhibited reduced AH-mediated membrane binding, while membrane binding of control cytochrome b5 remained unaffected. Similarly, trypsin treatment of the nanosensor coated with cellular membranes abolished AH peptide binding to the cellular membranes but did not affect the binding of a control lipid-binding peptide. These results therefore suggest that a protein plays a critical role in mediating and stabilizing the binding of NS5A's AH to its target membrane. These results also demonstrate the successful development of a new nanosensor technology ideal both for studying the interaction between a protein and its target membrane and for developing inhibitors of that interaction.
Effectiveness of Combining Manual Therapy and Acupuncture on Temporomandibular Joint Dysfunction: A Retrospective Study
Authors: Shin Byung-Cheul , Ha Chung-Hyo , Song Yung-Sun , Lee Myeong Soo
Published: April 2007

This retrospective study investigated the effects of combining manual therapy and acupuncture on the pain and maximal mouth opening (MMO), which were associated with temporomandibular joint dysfunction (TMD). The 49 TMD patients (15 men, 34 women; mean age = 30.47 years, SD = 13.52 years) were treated with a combination of acupuncture and manual therapy two or three times a week at the hospital. The pain and maximal mouth opening were assessed before and after 1 and 4 weeks of treatment. The combination therapy produced significant changes in pain levels ( p < 0.001) and mouth opening ( p < 0.001). All pairwise non-parametric comparison showed a significant improvement in pain ( p < 0.05 for all pairs) and MMO ( p < 0.05 for all pairs). These findings suggest that combining manual therapy and acupuncture decreases the pain level and increases the MMO of TMD patients. However, future studies should further investigate the efficacy of combined treatment on TMD with more rigorous randomized clinical trials.
The Effect of Oculo-Acupuncture on Recovery from Ethylene Glycol-Induced Acute Renal Injury in Dogs
Authors: Liu Jianzhu , Song Kun-Ho , You Myung-Jo , Son Dong-Soo , Cho Sung-Whan , Kim Duck-Hwan
Published: April 2007

The potential recovery effect by oculo-acupuncture (OA) on ethylene glycol-induced acute renal injury in dogs was investigated. Acute renal damage was induced by ingestion of ethylene glycol in six mongrel dogs. The dogs were assigned to control (three dogs) and experimental (three dogs) groups. The control group did not receive any treatment, while the experimental group was treated with oculo-acupuncture at kidney/urinary bladder region plus zhong jiao region of the eyes after the induction of renal damage. Serum blood urea nitrogen (BUN), creatinine, sodium ( Na ), chloride ( Cl ), and potassium ( K ) were measured in both control and experimental groups. The blood RBC and Hb were also examined. The serum BUN and creatinine activities in the experimental group were lower than those in the control group, the serum Na and Cl had the irregular change in both groups, and the blood Hb in the control and experimental group showed decreasing tendency. Significant differences were observed on the 3rd and 7th day in BUN, 7th day in creatinine, 2nd day in Na and Cl , and 7th day in Hb when compared to the control group. Whereas, serum K concentration and RBC in the experimental group did not change significantly. The recovery findings of the renal injury were also observed in the experimental group histopathologically.

In conclusion, OA therapy (kidney/urinary bladder region plus zhong jiao region) was effective for recovery of the renal injury induced by ethylene glycol in dogs.
Administration of Tauroursodeoxycholic Acid (TUDCA) Reduces Apoptosis Following Myocardial Infarction in Rat
Authors: Rivard Andrew L. , Steer Clifford J. , Kren Betsy T. , Rodrigues Cecilia M. P. , Castro Rui E. , Bianco Richard W. , Low Walter C.
Published: April 2007

Black bear bile has been used in traditional Chinese medicine to treat liver and eye related illnesses for centuries. A major constituent of bile is ursodeoxycholic acid (UDCA). Recent analysis of the cellular effects of UDCA and its taurine conjugate tauroursodeoxycholic acid (TUDCA) have demonstrated their antiapoptotic properties through regulation of Bcl-2 family and survival signaling proteins (Bax, Bad, phosphatidylinositol-3-kinase). In this study, we tested the hypothesis that TUDCA administered to rats prior to a myocardial infarction (MI) would exhibit anti-apoptotic effects and improve cardiac function. Prior to ligation of the left anterior descending (LAD) coronary artery, TUDCA (50 mg/ml, 400 mg/kg, IV) or PBS was administered to rats. Animals were sacrificed 24 hours after ligation for terminal transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) and caspase-3 activity to assess apoptosis. Additional TUDCA or PBS treated rats underwent pre-operative,1 and 4 week transthoracic ultrasounds to assess heart function by quantification of shortening fraction (SF) and infarct area. TUNEL labeling of the cardiac tissue revealed a significant reduction in apoptotic cells in rats given TUDCA prior to ischemic injury ( p = 0.05). In support of reducing apoptosis, caspase-3 activity in the TUDCA treated animals also decreased ( p = 0.02). By 4 weeks, a significantly smaller infarct area was present in the TUDCA group compared to the PBS group (0.05 vs. 0.13 cm2, p = NS) and there was also an improvement in SF. The results provide evidence for TUDCA as a viable treatment for reducing apoptosis in a model of myocardial infarction. Additional studies will distinguish the functional result of improved cell survival following infarction, suggesting the potential for clinical application of this anti-apoptotic drug in treatment of acute MI.
MAGNETIC TRANSLATION AND DEGENERACY OF SOME LANDAU STATES STUDIED BY VIRTUE OF THE ENTANGLED STATE REPRESENTATION
Authors: FAN HONG-YI , JIANG NIAN-QUAN
Published: April 2007

By virtue of the entangled state representation, we show that a new function space for Landau state vectors can be constructed. As a result, the magnetic translation and degeneracy of some Landau states can be analyzed in a direct and transparent manner.
INVESTIGATION OF THE QUANTUM CHAOS OF INTERNAL ROTATIONAL MOTION IN POLYATOMIC MOLECULES
Authors: UGULAVA A. , CHOTORLISHVILI L. , GVARJALADZE T. , CHKHAIDZE S.
Published: April 2007

Polyatomic molecules can perform internal rotational motion of two types: torsional oscillation and free rotation of one part of the molecule with respect to the other part. On the phase plane, these two types of motion are separated by the separatrix. Phase trajectories, originated as a result of periodical external force action on the system, have stochastic nature. For quantum consideration, regarding the motion near to the classical separatrix, transition from the pure quantum-mechanical state to the mixed one takes place. Originating at that mixed state, this must be considered as the quantum analog of the classical dynamic stochasticity and is named as the quantum chaos. This work is devoted to the investigation of the quantum chaos manifestation in the polyatomic molecules, which have a property that performs internal rotation. For the molecule of ethane C 2 H 6, the emergence of quantum chaos and possible ways of its experimental observation has been studied. It is shown that radio-frequency field can produce the non-direct transitions between rotational and oscillatory states. These transitions, being the sign of the existence of quantum chaos, are able to change population levels sizeably. Due to this phenomenon, experimental observation of the infrared absorption is possible.
TWO ELECTRONS IN A HONEYCOMB LATTICE
Authors: BASU SAURABH , KADOLKAR C. Y. , GOVEAS NEENA
Published: April 2007

The formation of bound pair of electrons is studied using a t–J–U model on a two-dimensional honeycomb lattice for zero electron density. We set up the equations of motion (EOM) for two electrons in a two-sublattice basis and hence solve for the critical exchange coupling necessary to form a pair on a finite size lattice. The results extrapolated to the thermodynamic limit (N → ∞) and in the strong coupling regime (U / t → ∞) identifies Jc / t = 2. Calculation of binding energies at J = Jc provide support for the above result.
EXACT SOLITONS IN THE GROSS–PITAEVSKII EQUATION WITH TIME-MODULATED NONLINEARITY
Authors: LIANG Z. X. , ZHANG Z. D.
Published: April 2007

Exact solitonic solutions of the Gross–Pitaevskii equation with time-modulated nonlinearity of a(t) = a0 / (t + t0) are obtained. With help of these solutions, we analyze the properties of Feshbach-managed solitons in Bose–Einstein condensates in details. Our results show that the parameters of atomic matter waves can be manipulated by proper variation of the scattering length. In particular, an exact two-soliton solution is given, from which, it is shown that the separation between the neighboring solitons can be effectively maintained by allowing the solitons to have unequal initial amplitudes.
Wide-spaced sampling for delineation of geochemical provinces in desert terrains, northwestern China
Authors: Wang Xueqiu , Chi Qinghua , Liu Hongyan , Nie Lanshi , Zhang Bimin
Published: April 2007

Desert terrains are widely distributed in northwestern and northern China, but remain largely unexplored or under-explored. In the past, lag materials (coarse fraction of regolith) have been sampled for regional geochemical surveys. This sampling method was successful in mountainous and hilly regions, but it failed in areas of lower relief, such as slopes, plains, alluvial valleys and basins.

Studies conducted since 1999 were aimed at understanding the environment and the nature of geochemical dispersion in order to find a cost-effective, wide-spaced sampling method for delineation of geochemical provinces. The results show that many elements related to mineral deposits are concentrated in the fine fraction (<120 mesh, 125 μm) in the weakly cemented horizon in the upper part of the vertical profile. Wide-spaced sampling was carried out in an area of
c.
150 000 km
2
at a density of one sample per 100 km
2
. Samples were collected from the weakly cemented sandy clay-rich horizon at a depth of 15–30 cm and sieved to <120 mesh in the field. The sieved samples were ground to 200 mesh (75 μm). Thirty-four elements were determined by ICP-MS, GF-AAS and AFS. A geochemical atlas and interpreted geochemical maps were generated using a GIS.

Geochemical provinces of Au, Cu and U have been recognized. Five Au provinces, with threshold values of more than 2.0 ppb Au, have been delineated. Three of these are consistent with known large Au deposits, and preliminary follow-up surveys indicate that the other two are prospective for undiscovered Au deposits. Seven Cu provinces have been delineated, of which three are endowed with hydrothermal Cu deposits, porphyry Cu deposits and Cu-Ni deposits, respectively. Two provinces of U associated with Mo were delineated in the basin. One of them contains a large sandstone-hosted U deposit and in the other, a large new U deposit was discovered by follow-up drilling.
An evaluation of methods for imputation of missing trace element data in groundwaters
Authors: Dickson Bruce L. , Giblin Angela M.
Published: April 2007

Groundwater data-sets with pH and major cation–anion chemistry are widely available but data that include trace metals are much rarer. This paper examines two methods of data imputation to predict U concentrations using pH, major cations, anions and F in a data-set where some of the U concentrations are missing. The methods evaluated were self-organizing maps (SOM) and expectation maximization (EM). Evaluations were made using a groundwater data-set of 187 samples from NSW and Victoria, which contained a wide range of U concentrations up to 225 μg/l. Tests made by setting 25% and 50% of the U concentrations to missing showed that, at 25% missing, SOM gave reasonable estimates, identifying all the samples with higher U. EM did not clearly identify the higher samples. At 50% missing, neither method could accurately identify the higher U concentrations. Thus, imputation using samples with missing data included in the training data-set does not appear to be practical. However, a SOM pre-trained on a data-set with no missing U concentrations may be used to impute U concentrations for samples with 100% missing U data. Training using the original data-set and then imputing concentrations for a second set of 360 samples showed that the samples with higher measured U concentrations could generally be identified, but that other samples were also estimated to be U-rich. This method could substantially reduce the number of samples in a large data-set requiring further investigation.

The performance of imputation for U reflects the complex interaction of water chemistry, geology and mineralogy that actually determines the U concentrations. Imputation is a useful method for improving estimates of data statistics. SOM, through its model-free approach, is a useful addition to the numerical analysis toolbox for geochemists.
Downhole lithogeochemical patterns relating to chemostratigraphy and igneous fractionation processes in the Golden Mile dolerite, Western Australia
Authors: O'Connor-Parsons Tansy , Stanley Clifford R.
Published: April 2007

The Fimiston Superpit, Kalgoorlie, Western Australia, is the largest gold mine in Australia. The main host to mineralization, the differentiated Golden Mile dolerite (GMD) sill, has undergone several episodes of deformation, metamorphism and intense deuteric and hydrothermal alteration. This has replaced the primary silicate minerals but at least partially preserved the original igneous textures in the intrusion, upon which its ten horizontally stratified units are defined. An examination of petrologic and lithogeochemical data from drill-core through the GMD sill was undertaken to identify mineralogical and geochemical parameters that confirm stratigraphic position within the igneous stratigraphy. These parameters facilitate construction of palinspastic reconstructions of cross-sections through the GMD sill, and will thus enable identification and testing of deep exploration targets.

Results also provide more detailed information about the history of the intrusion. Conserved element ratio analysis indicates that the intrusion formed from a single cooling magma body. Plagioclase and pyroxene fractionation occurred throughout during cooling, but magnetite fractionation occurred only after
c.
50% crystallization. Calculations reveal unbalanced enrichments and depletions of magnetite-borne Ti and V that are possibly caused by tapping of the magma chamber after magnetite saturation, or by lateral variations in the magma chamber, possibly due to turbulence. Magnetite saturation also triggered saturation of immiscible sulphide droplets, which gravitationally settled from the magma and fractionated Cu and Ni.

In summary, textural and compositional variations within the GMD can be explained by simple igneous processes that affected the magma chamber during cooling. The parameters that track these processes allow a stratigraphic re-assessment of the original ten stratigraphic units. Only seven units bounded by sharp and consistent contacts defined by obvious mineralogical and lithogeochemical breaks can be confidently discerned.
Molecular Architectonic on Metal Surfaces
Authors: Barth Johannes V.
Published: April 2007

The engineering of highly organized systems from instructed molecular building blocks opens up new vistas for the control of matter and the exploration of nanodevice concepts. Recent investigations demonstrate that well-defined surfaces provide versatile platforms for steering and monitoring the assembly of molecular nanoarchitectures in exquisite detail. This review delineates the principles of noncovalent synthesis on metal substrates under ultrahigh vacuum conditions and briefly assesses the pertaining terminology—self-assembly, self-organization, and self-organized growth. It presents exemplary scanning-tunneling-microscopy observations, providing atomistic insight into the self-assembly of organic clusters, chains, and superlattices, and the metal-directed assembly of low-dimensional coordination architectures. This review also describes hierarchic-assembly protocols leading to intricate multilevel order. Molecular architectonic on metal surfaces represents a versatile rationale to realize structurally complex nanosystems with specific shape, composition, and functional properties, which bear promise for technological applications.
Exciton Photophysics of Carbon Nanotubes
Authors: Dresselhaus Mildred S. , Dresselhaus Gene , Saito Riichiro , Jorio Ado
Published: April 2007

The goal of this chapter is to review the importance of excitons to single-wall carbon nanotube (SWNT) optics. We have developed the presentation for both researchers in the SWNT field who want to learn more about the unusual aspects of SWNT exciton photophysics and researchers more knowledgeable about the physics of excitons, but not about SWNT physics. Excitons in SWNTs are special because graphite has two energy bands at the Fermi energy related to time-reversal symmetry and because SWNTs are actually one dimensional. This review discusses both theoretical and experimental points of view, thus aiming to provide a summary of the most important work in the field, as well as to identify open questions.
Selective knockdown of AT1receptors by RNA interference inhibits Val5-ANG II endocytosis and NHE-3 expression in immortalized rabbit proximal tubule cells
Authors: Li Xiao C. , Zhuo Jia L.
Published: April 2007

Receptor-mediated endocytosis of extracellular ANG II has been suggested to play an important role in the regulation of proximal tubule cell (PTC) function. Using immortalized rabbit PTCs as an in vitro cell culture model, we tested the hypothesis that extracellular ANG II is taken up by PTCs through angiotensin type 1 receptor (AT1; or AT1a) receptor-mediated endocytosis and that inhibition of ANG II endocytosis using a selective AT1receptor small-interfering RNA (siRNA; AT1R siRNA) or endocytotic inhibitors exerts a physiological effect on total and apical sodium and hydrogen exchanger isoform 3 (NHE-3) protein abundance. Western blots and live cell imaging with FITC-labeled ANG II confirmed that transfection of PTCs with a human specific AT1R siRNA for 48 h selectively knocked down AT1receptor protein by 76 ± 5% ( P < 0.01), whereas transfection with a scrambled siRNA had little effect. In nontransfected PTCs, exposure to extracellular ANG II (1 nM) for 60 min at 37°C increased intracellular ANG II accumulation by 67% (control: 566 ± 55 vs. ANG II: 943 ± 160 pg/mg protein, P < 0.05) and induced mitogen-activated protein kinase extracellular signal-regulated kinase (ERK) 1/2 phosphorylation (163 ± 15% of control, P < 0.01). AT1R siRNA reduced ANG II endocytosis to a level similar to losartan, which blocks cell surface AT1receptors (557 ± 37 pg/mg protein, P < 0.05 vs. ANG II), or to colchicine, which disrupts cytoskeleton microtubules (613 ± 12 pg/mg protein, P < 0.05 vs. ANG II). AT1R siRNA, losartan, and colchicine all attenuated ANG II-induced ERK1/2 activation and total cell lysate and apical membrane NHE-3 abundance. The scrambled siRNA had no effect on ANG II endocytosis, ERK1/2 activation, or NHE-3 expression. These results suggest that AT1receptor-mediated endocytosis of extracellular ANG II may regulate proximal tubule sodium transport by increasing total and apical NHE-3 proteins.
Viscoelasticity of the human red blood cell
Authors: Puig-de-Morales-Marinkovic Marina , Turner Kevin T. , Butler James P. , Fredberg Jeffrey J. , Suresh Subra
Published: April 2007

We report here the first measurements of the complex modulus of the isolated red blood cell (RBC). Because the RBC is often larger than capillary diameter, important determinants of microcirculatory function are RBC deformability and its changes with pathologies, such as sickle cell disease and malaria. A functionalized ferrimagnetic microbead was attached to the membrane of healthy RBC and then subjected to an oscillatory magnetic field. The resulting torque caused cell deformation. From the oscillatory forcing and resulting bead motions, which were tracked optically, we computed elastic and frictional moduli, g′ and g‴, respectively, from 0.1 to 100 Hz. The g′ was nearly frequency independent and dominated the response at all but the highest frequencies measured. Over three frequency decades, g‴ increased as a power law with an exponent of 0.64, a result not predicted by any simple model. These data suggest that RBC relaxation times that have been reported previously, and any models that rest upon them, are artifactual; the artifact, we suggest, arises from forcing to an exponential fit data of limited temporal duration. A linear range of response was observed, but, as forcing amplitude increased, nonlinearities became clearly apparent. A finite element model suggests that membrane bending was localized to the vicinity of the bead and dominated membrane shear. While the mechanisms accounting for these RBC dynamics remain unclear, methods described here establish new avenues for the exploration of connections among the mechanical, chemical, and biological characteristics of the RBC in health and disease.
Eosinophilia is induced in the colon of Th2-sensitized mice upon exposure to locally expressed antigen
Authors: Zhu Qing , Thomson Christopher W. , Zhang Guofeng , Stämpfli Martin , McDermott Mark R. , Collins Stephen M. , Gauldie Jack
Published: April 2007

Eosinophilic inflammation is a feature of a variety of gastrointestinal (GI) disorders including eosinophil-associated GI disorder, allergy, inflammatory bowel disease, and parasite infection. Elucidating the mechanisms of eosinophil infiltration into the GI tract is important to the understanding of multiple disease processes. We hypothesize that eosinophilia in the large intestine (colon) can be induced by an antigen in a host that is associated with Th2-skewed antigen-specific immune responses. To investigate the importance of antigenic triggering, we established polarized antigen-specific Th2 type responses in BALB/c mice, using ovalbumin in conjunction with aluminum hydroxide. Upon challenge at the colonic mucosa through transient (3–4 days) expression of the antigen gene encoded in an adenovirus vector, sensitized animals developed significant subepithelial colonic inflammation, characterized by marked eosinophilic infiltration, and the presence of enlarged and increased numbers of lymphoid follicles. The alterations peaked around day 5 and resolved over the next 5–10 days, and no epithelial cell damage was detected through the entire course. Administration of a control (empty) adenovirus vector did not lead to any pathological changes. These data suggest that colonic eosinophilia can be induced by exposure to an antigen associated with preexisting Th2-skewed responses. Thus the model established here may provide a useful tool to study GI and, in particular, colonic inflammation with respect to underlying mechanisms involved in the recruitment and the immediate function of eosinophils.
Arginine vasopressin inhibits Kir6.1/SUR2B channel and constricts the mesenteric artery via V1a receptor and protein kinase C
Authors: Shi Weiwei , Cui Ningren , Shi Yun , Zhang Xiaoli , Yang Yang , Jiang Chun
Published: April 2007

Kir6.1/SUR2B channel is the major isoform of KATP channels in the vascular smooth muscle. Genetic disruption of either subunit leads to dysregulation of vascular tone and regional blood flows. To test the hypothesis that the Kir6.1/SUR2B channel is a target molecule of arginine vasopressin (AVP), we performed studies on the cloned Kir6.1/SUR2B channel and cell-endogenous KATP channel in rat mesenteric arteries. The Kir6.1/SUR2B channel was expressed together with V1a receptor in the HEK-293 cell line. Whole cell currents of the transfected HEK cells were activated by KATP channel opener pinacidil and inhibited by KATP channel inhibitor glibenclamide. AVP produced a concentration-dependent inhibition of the pinacidil-activated currents with IC50 2.0 nM. The current inhibition was mediated by a suppression of the open-state probability without effect on single-channel conductance. An exposure to 100 nM PMA, a potent PKC activator, inhibited the pinacidil-activated currents, and abolished the channel inhibition by AVP. Such an effect was not seen with inactive phorbol ester. A pretreatment of the cells with selective PKC blocker significantly diminished the inhibitory effect of AVP. In acutely dissociated vascular smooth myocytes, AVP strongly inhibited the cell-endogenous KATP channel. In isolated mesenteric artery rings, AVP produced concentration-dependent vasoconstrictions with EC50 6.5 nM. At the maximum effect, pinacidil completely relaxed vasoconstriction in the continuing exposure to AVP. The magnitude of the AVP-induced vasoconstriction was significantly reduced by calphostin-C. These results therefore indicate that the Kir6.1/SUR2B channel is a target molecule of AVP, and the channel inhibition involves Gq-coupled V1a receptor and PKC.
Paraventricular opioids alter intake of high-fat but not high-sucrose diet depending on diet preference in a binge model of feeding
Authors: Naleid Amy M. , Grace Martha K. , Chimukangara Munya , Billington Charles J. , Levine Allen S.
Published: April 2007

Previous work from our laboratory indicates that when rats are given a choice between a high-fat and a high-sucrose diet, opioid blockade with naltrexone (NTX) in a reward-related site (central amygdala) inhibits intake of the preferred diet only, whereas NTX injected into a homeostasis-related site, such as the hypothalamic paraventricular nucleus (PVN), inhibits intake of both diets. However, other work suggests that opioids increase intake of fat specifically. The present study further investigates the role of PVN opioids in food choices made by calorically-replete animals. We used a binge model with chow-maintained rats given 3-h access to a choice of a high-fat or high-sucrose diet 3 days a week. We hypothesized that intra-PVN injection of the μ-opioid agonist, DAMGO (0, 0.025, 0.25, and 2.5 nmol) would enhance, and NTX (0, 10, 30, and 100 nmol) would inhibit intake of both diets to an equal extent. We found that when animals were divided into groups according to sucrose or fat preference, DAMGO increased fat intake in fat-consuming animals, while having no effect on intake of either diet in sucrose-consuming animals. NTX, however, inhibited fat intake in both groups. Intra-PVN NTX did not inhibit intake of sucrose when presented in the absence of a fat choice, but did so when injected peripherally. Furthermore, intra-PVN and systemic NTX inhibited intake of chow by 24-h-food-deprived animals. These results indicate a complex role for PVN opioids in food intake with preference, nutrient type, and energy state affecting the ability of these compounds to change behavior.
Restriction of placental function alters heart development in the sheep fetus
Authors: Morrison J. L. , Botting K. J. , Dyer J. L. , Williams S. J. , Thornburg K. L. , McMillen I. C.
Published: April 2007

Placental insufficiency, resulting in restriction of fetal substrate supply, is a major cause of intrauterine growth restriction (IUGR) and increased neonatal morbidity. Fetal adaptations to placental restriction maintain the growth of key organs, including the heart, but the impact of these adaptations on individual cardiomyocytes is unknown. Placental and hence fetal growth restriction was induced in fetal sheep by removing the majority of caruncles in the ewe before mating (placental restriction, PR). Vascular surgery was performed on 13 control and 11 PR fetuses at 110–125 days of gestation (term: 150 ± 3 days). PR fetuses with a mean gestational Po2 < 17 mmHg were defined as hypoxic. At postmortem (<135 or >135 days), fetal hearts were collected, and cardiomyocytes were isolated and fixed. Proliferating cardiomyocytes were counted by immunohistochemistry of Ki67 protein. Cardiomyocytes were stained with methylene blue to visualize the nuclei, and the proportion of mononucleated cells and length and width of cardiomyocytes were measured. PR resulted in chronic fetal hypoxia, IUGR, and elevated plasma cortisol concentrations. Although there was no difference in relative heart weights between control and PR fetuses, there was an increase in the proportion of mononucleated cardiomyocytes in PR fetuses. Whereas mononucleated and binucleated cardiomyocytes were smaller, the relative size of cardiomyocytes when expressed relative to heart weight was larger in PR compared with control fetuses. The increase in the relative proportion of mononucleated cardiomyocytes and the relative sparing of the growth of individual cardiomyocytes in the growth-restricted fetus are adaptations that may have long-term consequences for heart development in postnatal life.
Characterization of renin-angiotensin system enzyme activities in cultured mouse podocytes
Authors: Velez Juan Carlos Q. , Bland Alison M. , Arthur John M. , Raymond John R. , Janech Michael G.
Published: April 2007

Intraglomerular ANG II has been linked to glomerular injury. However, little is known about the contribution of podocytes (POD) to intraglomerular ANG II homeostasis. The aim of the present study was to examine the processing of angiotensin substrates by cultured POD. Our approach was to use matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry for peptide determination from conditioned cell media and customized AQUA peptides for quantification. Immortalized mouse POD were incubated with 1-2 μM ANG I, ANG II, or the renin substrate ANG-(1-14) for different time intervals and coincubated in parallel with various inhibitors. Human mesangial cells (MES) were used as controls. POD incubated with 1 μM ANG I primarily formed ANG-(1-9) and ANG-(1-7). In contrast, MES incubated with ANG I primarily generated ANG II. In POD, ANG-(1-7) was the predominant product, and its formation was inhibited by a neprilysin inhibitor. Modest angiotensin-converting enzyme (ACE) activity was also detected in POD, although only after cells were incubated with 2 μM ANG I. In addition, we observed that POD degraded ANG II into ANG III and ANG-(1-7). An aminopeptidase A inhibitor inhibited ANG III formation, and an ACE2 inhibitor led to ANG II accumulation. Furthermore, we found that POD converted ANG-(1-14) to ANG I and ANG-(1-7). This conversion was inhibited by a renin inhibitor. These findings demonstrate that POD express a functional intrinsic renin-angiotensin system characterized by neprilysin, aminopeptidase A, ACE2, and renin activities, which predominantly lead to ANG-(1-7) and ANG-(1-9) formation, as well as ANG II degradation. These findings may reflect a specific role of POD in maintenance of intraglomerular renin-angiotensin system balance.
Why isd-serine nephrotoxic and α-aminoisobutyric acid protective?
Authors: Krug Alexander W. , Völker Katharina , Dantzler William H. , Silbernagl Stefan
Published: April 2007

d-Serine selectively causes necrosis of S3segments of proximal tubules in rats. This leads to aminoaciduria and glucosuria. Coinjection of the nonmetabolizable amino acid α-aminoisobutyric acid (AIB) prevents the tubulopathy. d-serine is selectively reabsorbed in S3, thereby gaining access to peroxisomal d-amino acid oxidase (d-AAO). d-AAO-mediated metabolism produces reactive oxygen species. We determined the fractional excretion of amino acids and glucose in rats after intraperitoneal injection of d-serine alone or together with reduced glutathione (GSH) or AIB. Both compounds prevented the hyperaminoaciduria. We measured GSH concentrations in renal tissue before (control) and after d-serine injection and found that GSH levels decreased to ∼30% of control. This decrease was prevented when equimolar GSH was coinjected with d-serine. To find out why AIB protected the tubule from d-serine toxicity, we microinfused d-[14C]serine or [14C]AIB (0.36 mmol/l) together with [3H]inulin in late proximal tubules in vivo and measured the radioactivity in the final urine. Fractional reabsorption of d-[14C]serine and [14C]AIB amounted to 55 and 70%, respectively, and 80 mmol/l of AIB or d-serine mutually prevented reabsorption to a great extent. d-AAO activity measured in vitro (using d-serine as substrate) was not influenced by a 10-fold higher AIB concentration. We conclude from these results that 1) d-AAO-mediated d-serine metabolism lowers renal GSH concentrations and thereby provokes tubular damage because reduction of reactive oxygen species by GSH is diminished and 2) AIB prevents d-serine-induced tubulopathy by inhibition of d-serine uptake in S3segments rather than by interfering with intracellular d-AAO-mediated d-serine metabolism.
Antioxidant vitamins induce angiogenesis in the normal pig kidney
Authors: Daghini Elena , Zhu Xiang-Yang , Versari Daniele , Bentley Michael D. , Napoli Claudio , Lerman Amir , Lerman Lilach O.
Published: April 2007

The effects of chronic supplementation with antioxidant vitamins on angiogenesis are controversial. The aim of the present study was to evaluate in kidneys of normal pigs the effect of chronic supplementation with vitamins E and C, at doses that are effective in reducing oxidative stress and attenuating angiogenesis under pathological conditions. Domestic pigs were randomized to receive a 12-wk normal diet without ( n = 6) or with antioxidant vitamins supplementation (1g/day vitamin C, 100 IU·kg−1·day−1vitamin E; n = 6). Electron beam computed tomography (CT) was used to evaluate renal cortical vascular function in vivo, and micro-CT was to assess the spatial density and average diameter of cortical microvessels (diameter <500 μm) ex vivo. Oxidative stress and expressions of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1α were evaluated in renal tissue. The effects of increasing concentrations of the same vitamins on redox status and angiogenesis were also evaluated in human umbilical vascular endothelial cells (HUVEC). Compared with normal pigs, the density of cortical transmural microvessels was significantly greater in vitamin-supplemented pigs (149.0 ± 11.7 vs. 333.8 ± 48.1 vessel/cm2, P < 0.05), whereas the cortical perfusion response to ACh was impaired. This was accompanied by a significant increase in tissue oxidative stress and levels of VEGF and HIF-1α. A low dose of antioxidant decreased, whereas a high dose increased, HUVEC oxidative stress and angiogenesis, which was partly mediated by hydrogen peroxide. Antioxidant vitamin supplementation can increase tissue oxidative redox and microvascular proliferation in the normal kidney, probably due to a biphasic effect that depends on basal redox balance.
Decoding M1 Neurons During Multiple Finger Movements
Authors: Hamed S. Ben , Schieber M. H. , Pouget A.
Published: April 2007

We tested several techniques for decoding the activity of primary motor cortex (M1) neurons during movements of single fingers or pairs of fingers. We report that single finger movements can be decoded with >99% accuracy using as few as 30 neurons randomly selected from populations of task-related neurons recorded from the M1 hand representation. This number was reduced to 20 neurons or less when the neurons were not picked randomly but selected on the basis of their information content. We extended techniques for decoding single finger movements to the problem of decoding the simultaneous movement of two fingers. Movements of pairs of fingers were decoded with 90.9% accuracy from 100 neurons. The techniques we used to obtain these results can be applied, not only to movements of single fingers and pairs of fingers as reported here, but also to movements of arbitrary combinations of fingers. The remarkably small number of neurons needed to decode a relatively large repertoire of movements involving either one or two effectors is encouraging for the development of neural prosthetics that will control hand movements.
Evolution of Motor Memory During the Seconds After Observation of Motor Error
Authors: Huang Vincent S. , Shadmehr Reza
Published: April 2007

When a movement results in error, the nervous system amends the motor commands that generate the subsequent movement. Here we show that this adaptation depends not just on error, but also on passage of time between the two movements. We observed that subjects learned a reaching task faster, i.e., with fewer trials, when the intertrial time intervals (ITIs) were lengthened. We hypothesized two computational mechanisms that could have accounted for this. First, learning could have been driven by a Bayesian process where the learner assumed that errors are the result of perturbations that have multiple timescales. In theory, longer ITIs can produce faster learning because passage of time might increase uncertainty, which in turn increases sensitivity to error. Second, error in a trial may result in a trace that decays with time. If the learner continued to sample from the trace during the ITI, then adaptation would increase with increased ITIs. The two models made separate predictions: The Bayesian model predicted that when movements are separated by random ITIs, the learner would learn most from a trial that followed a long time interval. In contrast, the trace model predicted that the learner would learn most from a trial that preceded a long time interval. We performed two experiments to test for these predictions and in both experiments found evidence for the trace model. We suggest that motor error produces an error memory trace that decays with a time constant of about 4 s, continuously promoting adaptation until the next movement.
Development of Temporal Response Properties and Contrast Sensitivity of V1 and V2 Neurons in Macaque Monkeys
Authors: Zheng J. , Zhang B. , Bi H. , Maruko I. , Watanabe I. , Nakatsuka C. , Smith E. L. , Chino Y. M.
Published: April 2007

The temporal contrast sensitivity of human infants is reduced compared to that of adults. It is not known which neural structures of our visual brain sets limits on the early maturation of temporal vision. In this study we investigated how individual neurons in the primary visual cortex (V1) and visual area 2 (V2) of infant monkeys respond to temporal modulation of spatially optimized grating stimuli and a range of stimulus contrasts. As early as 2 wk of age, V1 and V2 neurons exhibited band-pass temporal frequency tuning. However, the optimal temporal frequency and temporal resolution of V1 neurons were much lower in 2- and 4-wk-old infants than in 8-wk-old infants or adults. V2 neurons of 8-wk-old monkeys had significantly lower optimal temporal frequencies and resolutions than those of adults. Onset latency was longer in V1 at 2 and 4 wk of age and was slower in V2 even at 8 wk of age than in adults. Contrast threshold of V1 and V2 neurons was substantially higher in 2- and 4-wk-old infants but became adultlike by 8 wk of age. For the first 4 wk of life, responses to high-contrast stimuli saturated more readily in V2. The present results suggest that although the early development of temporal vision and contrast sensitivity may largely depend on the functional maturation of precortical structures, it is also likely to be limited by immaturities that are unique to V1 and V2.
S-phase checkpoints regulate Apo2 ligand/TRAIL and CPT-11–induced apoptosis of prostate cancer cells
Authors: Ray Subrata , Shyam Sunitha , Fraizer Gail C. , Almasan Alexandru
Published: April 2007

As S-phase checkpoints play critical roles in maintaining genomic integrity and replicating the human genome correctly, understanding the molecular mechanism by which they regulate the therapeutic response is of great interest. Previously, we reported that the cytotoxic effect of a zinc-bound form of Apo2 ligand/tumor necrosis factor–related apoptosis-inducing ligand (Apo2L/TRAIL), which is currently evaluated in clinical trials, in combination with low-dose CPT-11, induces apoptosis of C4-2 human prostate cancer cells and tissues. Here, we show that apoptosis, induced synergistically by this combination treatment, was associated with accumulation of cells in early S phase, indicated by cell cycle analyses, increased proliferating cell nuclear antigen, and Chk2-Thr68 phosphorylation in tumors xenografted in mice. The combination treatment induced an S-phase checkpoint response through activation of Chk2 and Chk1 by the ataxia telangiectasia mutated and ataxia telangiectasia mutated and Rad3 related kinases, leading to phosphorylation and decreased Cdc25A levels. Cdc25A-dependent regulation of cyclin-dependent kinase 2 (Cdk2) and changes in association of p21WAF1/CIP1 and hSpy1 with Cdk2 resulted in inhibition of Cdk2-associated kinase activity. Knockdown of ataxia telangiectasia mutated/Chk2 and ataxia telangiectasia mutated and Rad3 related/Chk1 by small inhibitory RNAs abrogated the S-phase checkpoint and accelerated apoptosis, resulting in caspase-3 activation and poly(ADP-ribose) polymerase 1 cleavage following combination treatment. Thus, Apo2L/TRAIL + CPT-11 treatment–induced apoptosis is regulated through an S-phase checkpoint controlled by the Chk2-Cdc25A and Chk1-Cdc25A pathways and inhibition of Cdk2-associated kinase activity. Low-dose CPT-11 and aphidicolin increased the proportion of S-phase cells and sensitized cells to Apo2L/TRAIL, by inducing phosphatidylserine externalization, caspase activation, and poly(ADP-ribose) polymerase 1 cleavage. Combinations with S-phase arrest–inducing chemotherapeutic drugs may represent promising avenues for clinical development of Apo2L/TRAIL. [Mol Cancer Ther 2007;6(4):1368–78]
Dasatinib (BMS-354825) inhibits Stat5 signaling associated with apoptosis in chronic myelogenous leukemia cells
Authors: Nam Sangkil , Williams Ann , Vultur Adina , List Alan , Bhalla Kapil , Smith David , Lee Francis Y. , Jove Richard
Published: April 2007

Dasatinib (BMS-354825) is a novel, oral, potent, multi-targeted kinase inhibitor of Bcr-Abl and Src family kinases (SFK) and is a promising cancer therapeutic agent. Preclinical data indicate that dasatinib is 325-fold more potent than imatinib against cells expressing wild-type Bcr-Abl, and that dasatinib is active against 18 of 19 Bcr-Abl mutations known to cause imatinib resistance. Phase I clinical data show that dasatinib is well tolerated and highly effective for the treatment of imatinib-resistant/imatinib-intolerant chronic myelogenous leukemia (CML) and Philadelphia chromosome–positive acute lymphoblastic leukemia. However, the molecular mechanism of action of dasatinib is not fully understood. In this study, we confirm that dasatinib inhibits tyrosine phosphorylation of SFKs, including Src, Hck, and Lyn, in K562 human CML cells. Significantly, downstream signal transducer and activator of transcription 5 (Stat5) signaling is also blocked by dasatinib as shown by decreases in levels of phosphorylated Stat5 and Stat5 DNA-binding activities. In addition, dasatinib down-regulates expression of Stat5 target genes, including Bcl-x, Mcl-1, and cyclin D1. Consistent with these results, blockade of Stat5 signaling by dasatinib is accompanied by inhibition of cell proliferation and induction of apoptosis. Surprisingly, Stat5 DNA-binding activities are enhanced with increasing cell density, which is associated with resistance to apoptosis by dasatinib. Our findings indicate that inhibition of Stat5 signaling downstream of Bcr-Abl/SFKs contributes to the action of dasatinib, and, conversely, that increasing cell density up-regulates Stat5 activation and confers resistance to dasatinib. Moreover, the level of phosphorylated Stat5 in CML cells represents a mechanistically relevant biomarker for monitoring inhibition of Bcr-Abl signaling by dasatinib in CML patients using convenient immunocytochemical assays. [Mol Cancer Ther 2007;6(4):1400–5]