bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellular and Viral Factors Regulate the Varicella-Zoster Virus gE Promoter during Viral Replication
Authors: Berarducci Barbara , Sommer Marvin , Zerboni Leigh , Rajamani Jaya , Arvin Ann M.
Published: July 2007

Varicella-zoster virus (VZV) glycoprotein E (gE) is essential for viral replication and is involved in cell-to-cell spread, secondary envelopment, and entry. We created a set of mutations in the gE promoter to investigate the role of viral and cellular transcriptional factors in regulation of the gE promoter. Deletion or point mutation of the two Sp1 sites in the gE promoter abolished Sp1 binding and IE62-mediated transactivation of the gE promoter in vitro. Incorporation of the deletion or the point mutations disrupting both of the Sp1 binding sites into the VZV genome was not compatible with viral replication. A point mutation altering the atypical Sp1 binding site was lethal, while altering the second site impaired VZV replication significantly, indicating functional differences between the two Sp1 binding sites. Deletions in the gE promoter that abolished putative binding sites for cellular transcriptional factors other than Sp1, identified by bioinformatics analysis, were inserted in the VZV genome. Replication of the viruses with mutations of the gE promoter did not differ from control recombinants in melanoma cells or primary human tonsil T cells in vitro. These deletions did not affect infection of human skin xenografts in SCIDhu mice. These results indicate that Sp1 is required for IE62-mediated transactivation of the gE promoter and that this transcriptional factor appears to be the only cellular factor essential for regulation of the gE promoter.
A Potential α-Helix Motif in the Amino Terminus of LANA Encoded by Kaposi's Sarcoma-Associated Herpesvirus Is Critical for Nuclear Accumulation of HIF-1α in Normoxia
Authors: Cai Qiliang , Murakami Masanao , Si Huaxin , Robertson Erle S.
Published: July 2007

Hypoxia-inducible factor 1 (HIF-1) is a ubiquitously expressed transcriptional regulator involved in induction of numerous genes associated with angiogenesis and tumor growth. Kaposi's sarcoma, associated with increased angiogenesis, is a highly vascularized, endothelial cell-derived tumor. Previously, we have shown that the latency-associated nuclear antigen (LANA) encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) targets the HIF-1α suppressors von Hippel-Lindau protein and p53 for degradation via its suppressor of cytokine signaling-box motif, which recruits the EC
5
S ubiquitin complex. Here we further show that HIF-1α was aberrantly accumulated in KSHV latently infected primary effusion lymphoma (PEL) cells, as well as HEK293 cells infected with KSHV, and also show that a potential α-helical amino-terminal domain of LANA was important for HIF-1α nuclear accumulation in normoxic conditions. Moreover, we have now determined that this association was dependent on the residues 46 to 89 of LANA and the oxygen-dependent degradation domain of HIF-1α. Introduction of specific small interfering RNA against LANA into PEL cells also resulted in a diminished nuclear accumulation of HIF-1α. Therefore, these data show that LANA can function not only as an inhibitor of HIF-1α suppressor proteins but can also induce nuclear accumulation of HIF-1α during KSHV latent infection.
The Kaposi's Sarcoma-Associated Herpesvirus LANA Protein Stabilizes and Activates c-Myc
Authors: Liu Jianyong , Martin Heather J. , Liao Gangling , Hayward S. Diane
Published: July 2007

The Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) protein is functionally pleiotropic. LANA contributes to KSHV-associated pathogenesis, in part, by increasing entry of cells into S phase through a process that is driven by LANA interaction with the serine-threonine kinase glycogen synthase kinase 3 (GSK-3) and stabilization of β-catenin. We now show that LANA affects the activity of another protein involved in cell cycle regulation, c-Myc. Sequencing of c-Myc coding sequences revealed that c-Myc in KSHV-positive primary effusion lymphoma (PEL) cell lines is wild type in the N-terminal region that regulates c-Myc protein stability. Despite this, c-Myc in PEL cells is stabilized. In LANA-expressing cells, inactivation of nuclear GSK-3 reduced phosphorylation of c-Myc at Thr58 and contributed to c-Myc stabilization by decreasing c-Myc ubiquitination. Phosphorylation of c-Myc on Ser62 also affects c-Myc stability and function. We now show that LANA increases the level of phosphorylated extracellular signal-regulated kinase 1 (ERK1) and increases ERK phosphorylation of c-Myc on Ser62. LANA also interacted with c-Myc, and c-Myc amino acids 147 to 220 were required for this interaction. LANA (L1006P) retained the ability to bind to c-Myc and activate ERK1, indicating that these events did not require LANA interaction with GSK-3. Thus, LANA stabilizes c-Myc; prevents the phosphorylation of c-Myc at Thr58, an event that promotes Myc-induced apoptosis; and independently stimulates phosphorylation of c-Myc at Ser62, an event that transcriptionally activates c-Myc. LANA-mediated manipulation of c-Myc function is likely to contribute to KSHV-associated tumorigenesis through the induction of c-Myc regulated cellular genes, as well as by the stimulation of cell cycle progression.
In Transduced Cells, the U
S
3 Protein Kinase of Herpes Simplex Virus 1 Precludes Activation and Induction of Apoptosis by Transfected Procaspase 3
Authors: Benetti Luca , Roizman Bernard
Published: July 2007

The U
S
3 protein kinase of herpes simplex virus 1 blocks apoptosis induced by replication-incompetent virus mutants, proapoptotic members of the Bcl-2 family of proteins, and by a variety of other agents that act at the premitochondrial level in the proapoptotic cascade. To define the role of U
S
3 in blocking apoptosis at the postmitochondrial level, we investigated the U
S
3 protein kinase in transduced cells that were either transfected with a plasmid encoding procaspase 3 or superinfected with a proapoptotic mutant virus lacking the gene encoding the infected cell protein no. 4. (i) We show that U
S
3 blocks the proteolytic cleavage that generates active caspase 3 from the transfected zymogen procaspase 3, concomitant with inhibition of apoptosis. (ii) Studies based on detection of fluorescence emitted upon cleavage of a synthetic caspase 3 substrate showed that expression of the U
S
3 kinase and appearance of the cleaved substrate were mutually exclusive. (iii) An affinity-purified glutathione
S
-transferase (GST)-U
S
3 fusion protein, but not the inactive GST-U
S
3(K220N) protein, phosphorylated procaspase 3 in vitro. The studies published earlier on the effect of U
S
3 on the upstream regulatory proteins and current studies suggest that the U
S
3 protein kinase may act on several proteins in the proapoptotic cascade to enable the virus to complete its replication.
Wild Mouse Variants of Envelope Genes of Xenotropic/Polytropic Mouse Gammaretroviruses and Their XPR1 Receptors Elucidate Receptor Determinants of Virus Entry
Authors: Yan Yuhe , Knoper Ryan C. , Kozak Christine A.
Published: July 2007

Mouse xenotropic and polytropic leukemia viruses (XMVs and PMVs) are closely related gammaretroviruses that use the XPR1 receptor for entry. To identify amino acid residues in XPR1 important for virus entry, we tested mouse cells derived from evolutionarily divergent species for susceptibility to prototypical PMVs, XMVs, and the wild mouse isolate CasE#1. CasE#1 has a variant XMV/PMV host range, and sequence analysis of the CasE#1
env
gene identifies segments related to PMVs and XMVs. Cells from the Asian mouse species
Mus pahari
show a unique pattern of susceptibility to these three viruses; these cells are susceptible to XMVs and CasE#1 but are resistant to PMVs, whereas NIH 3T3 cells show the reciprocal pattern, susceptibility to only PMVs. The
M. pahari
XPR1 gene differs from that of NIH 3T3 in the two extracellular loops (ECLs) previously shown to mediate virus entry (M. Marin, C. S. Tailor, A. Nouri, S. L. Kozak, and D. Kabat, J. Virol. 73:9362-9368, 1999, and N. S. Van Hoeven and A. D. Miller, Retrovirology 2:76, 2005). Using transfected hamster cells expressing chimeric and mutated XPR1s, we demonstrated that the susceptibility differences between NIH 3T3 and
M. pahari
cells are receptor mediated, that PMV entry requires residues in ECL3, that the CasE#1 entry determinant is in ECL4, and that determinants for XMV entry are in both ECL3 and ECL4. Additional substitutions in ECL3 and ECL4 modulate virus susceptibility and suggest that ECL3 and ECL4 may contribute to the formation of a single virus receptor site. The position of
M. pahari
at the base of the
Mus
phylogenetic tree indicates that XPR1-mediated susceptibility to XMVs is the ancestral type in this genus and that the phenotypic variants of mouse XPR1 likely arose in conjunction with exposure to gammaretrovirus infections and coevolutionary adaptations in the viral envelope.
Overlapping Roles of the Rous Sarcoma Virus Gag p10 Domain in Nuclear Export and Virion Core Morphology
Authors: Scheifele Lisa Z. , Kenney Scott P. , Cairns Tina M. , Craven Rebecca C. , Parent Leslie J.
Published: July 2007

Nucleocytoplasmic shuttling of the Rous sarcoma virus (RSV) Gag polyprotein is an integral step in virus particle assembly. A nuclear export signal (NES) was previously identified within the p10 domain of RSV Gag. Gag mutants containing deletions of the p10 NES or mutations of critical hydrophobic residues at positions 219, 222, 225, or 229 become trapped within the nucleus and exhibit defects in the efficiency of virus particle release. To investigate other potential roles for Gag nuclear trafficking in RSV replication, we created viruses bearing NES mutant Gag proteins. Viruses carrying p10 mutations produced low levels of particles, as anticipated, and those particles that were released were noninfectious. The p10 mutant viruses contained approximately normal amounts of Gag, Gag-Pol, and Env proteins and genomic viral RNA (vRNA), but several major structural defects were found. Thin-section transmission electron microscopy revealed that the mature particles appeared misshapen, while the viral cores were cylindrical, horseshoe-shaped, or fragmented, with some particles containing multiple small, electron-dense aggregates. Immature virus-like particles produced by the expression of Gag proteins bearing p10 mutations were also aberrant, with both spherical and tubular filamentous particles produced. Interestingly, the secondary structure of the encapsidated vRNA was altered; although dimeric vRNA was predominant, there was an additional high-molecular-weight fraction. Together, these results indicate that the p10 NES domain of Gag is critical for virus replication and that it plays overlapping roles required for the nuclear shuttling of Gag and for the maintenance of proper virion core morphology.
Herpes Simplex Virus Type 1 C-Terminal Variants of the Origin Binding Protein (OBP), OBPC-1 and OBPC-2, Cooperatively Regulate Viral DNA Levels In Vitro, and OBPC-2 Affects Mortality in Mice
Authors: Link Malen A. , Schaffer Priscilla A.
Published: July 2007

Two in-frame, C-terminal isoforms of the herpes simplex virus type 1 (HSV-1) origin binding protein (OBP), OBPC-1 and OBPC-2, and a unique C-terminal transcript, UL8.5, are specified by HSV-1 DNA. As the first isoform identified, OBPC-1 was initially assumed to be the product of the UL8.5 transcript. Recent evidence has demonstrated, however, that OBPC-1 is a cathepsin B-mediated cleavage product of OBP, suggesting that OBPC-2 is the product of the UL8.5 transcript. Because both OBPC-1 and -2 contain the majority of the OBP DNA binding domain, we hypothesized that both may be involved in regulating origin-dependent, OBP-mediated viral DNA replication. In this paper, we demonstrate that OBPC-2 is, indeed, the product of the UL8.5 transcript. The translational start site of OBPC-2 was mapped, and a virus (M571A) that does not express this protein efficiently was constructed. Using M571A, we have shown that OBPC-2 is able to bind origin DNA, even though it lacks seven N-terminal amino acid residues of the previously mapped OBP DNA binding domain, resulting in a revision of the limits of the OBP DNA binding domain. Consistent with their proposed roles in regulating viral DNA replication, OBPC-1 and -2 act together to down-regulate viral DNA replication in vitro. During functional studies in vivo, OBPC-2 was identified as a factor that increases mortality in the mouse ocular model of HSV-1 infection.
5-HT2A serotoninergic receptor in the locus coeruleus participates in the first phase of lipopolysaccharide-induced fever
Authors: da Silva Alexandre O. Fernandes , Gargaglioni Luciane H. , Branco Luiz G.S.
Published: July 2007

This study was aimed at testing the hypothesis that serotoninergic receptors in the locus coeruleus (LC) play a role in bacterial lipopolysaccharide-induced fever. To this end, 5-HT1A (WAY-100635; 3 μg/100 nL) and 5-HT2A (ketanserin; 2 μg/100 nL) antagonists were microinjected into the LC and body temperature was monitored by biotelemetry. Intra-LC microinjections of ketanserin or WAY-100635 caused no change in body temperature of euthermic animals. 5-HT2A antagonism abolished the first phase of the lipopolysaccharide-induced fever. Taken together, these results indicate that serotonin acting on 5-HT2A receptors in the LC mediates the first phase of the febrile response, whereas 5-HT1A receptors are not involved in the lipopolysaccharide-induced fever.
FORMATION AND GROWTH OF CLUSTERS IN COLLOIDAL SUSPENSIONS
Authors: HECHT MARTIN , HARTING JENS , HERRMANN HANS J.
Published: July 2007

Depending on the p H -value and salt concentration of Al 2 O 3 suspensions different microstructures can form. Especially the clustered one is of major interest for industrial purposes as found in the production of ceramics. In this paper we investigate the clustered microstructure by means of a coupled Stochastic Rotation Dynamics (SRD) and Molecular Dynamics (MD) simulation. In order to gain statistics within a system containing numerous clusters, large simulation volumes are needed. We present our parallel implementation of the simulation algorithm as well as a newly developed cluster detection and tracking algorithm. We then show first results of measured growth rates and cluster size distributions to validate the applicability of our method.
NUCLEATION AND GROWTH OF A SOLID PHASE IN A GAS EXPANDING INTO VACUUM
Authors: BRILLIANTOV NIKOLAI V. , SCHMIDT JÜRGEN , SPAHN FRANK
Published: July 2007

We study kinetics of homogeneous nucleation in over-saturated vapor expanding from a reservoir through a long channel into vacuum. Assuming adiabatic conditions for the gas, we derive an equation of state which accounts for the phase transformation of vapor into the condensed phase. To describe the growth rate of particles of the new phase gas kinetic theory is employed. We find the size-distribution of these particles, the temperature and flux velocity along the channel. Calculations are performed for the particular case of water vapor expanding to vacuum from its equilibrium state at the triple point. These conditions correspond presumably to the formation of the gas-dust plume, recently detected at Enceladus – the icy moon of Saturn. Our results, therefore, shed some light on this interesting astrophysical phenomenon.
ISOSPIN PARTICLE ON S2 WITH ARBITRARY NUMBER OF SUPERSYMMETRIES
Authors: HONG SOON-TAE , LEE JOOHAN , LEE TAE HOON , OH PHILLIAL
Published: July 2007

We study the supersymmetric quantum mechanics of an isospin particle in the background of spherically symmetric Yang–Mills gauge field. We show that on S2 the number of supersymmetries can be made arbitrarily large for a specific choice of the spherically symmetric SU (2) gauge field. However, the symmetry algebra containing the supercharges becomes nonlinear if the number of fermions is greater than two. We present the exact energy spectra and eigenfunctions, which can be written as the product of monopole harmonics and a certain isospin state. We also find that the supersymmetry is spontaneously broken if the number of supersymmetries is even.
QUARK MASSES AND MIXINGS IN E6×S3: A MONTE CARLO APPROACH
Authors: MORISI STEFANO
Published: July 2007

Recently the authors of arXiv:hep-ph/0510321 propose a GUT model for fermion masses and mixings with spontaneously broken S3 discrete flavor symmetry, where S3 is the permutation group of three objects. The S3 breaking pattern in the quark sector is not studied and need further investigation. Since in such a model the number of free parameters is greater than the number of experimental observables, an analytical fit of all the parameters is impossible. To go forward with the model building and to deal with this problem we have used a statistical analysis. We have found that S3 is totally broken and the up-type quarks matrix is approximatively diagonal while down-type quarks matrix is not symmetric and it is parametrized by three couplings, gd, [Formula: see text] and [Formula: see text]. It has been found that [Formula: see text] is slightly smaller than gd = 1 and it is of order one, while [Formula: see text] where λ is the Cabibbo angle. An analytical study of the dependence of Vcb and Vub from the couplings [Formula: see text] and [Formula: see text] is also presented.
TURBULENCE DEGRADED IMAGES RESTORATION BASED ON IMPROVED MULTIFRAME ITERATIVE LOOPS AND DATA MINING
Authors: LIU CHUNSHENG , ZHANG TIANXU , ZHANG BIYIN
Published: July 2007

In this paper a novel restoration algorithm based on iterative loops and data mining is proposed to restore the original object image from a few frames of aero-optics degraded images through the turbulence medium. Based on the iterative loops, the iterative mathematic models to estimate the random turbulent optical point spread functions and object image are built. A series of restoration experiments for both simulated and real aero-optics degraded images were performed to examine the proposed algorithm under a computerized simulation environment, which show that the proposed algorithm outperform previous algorithms and therefore is effective for practical applications.
Cellular recruitment and cytokine generation in a rat model of allergic lung inflammation are differentially modulated by progesterone and estradiol
Authors: de Oliveira Ana Paula Ligeiro , Domingos Helori Vanni , Cavriani Gabriela , Damazo Amilcar Sabino , dos Santos Franco Adriana Lino , Oliani Sonia Maria , Oliveira-Filho Ricardo Martins , Vargaftig Bernardo Boris , de Lima Wothan Tavares
Published: July 2007

We evaluated the role of estradiol and progesterone in allergic lung inflammation. Rats were ovariectomized (Ovx) and, 7 days later, were sensitized with ovalbumin (OA) and challenged after 2 wk with inhaled OA; experiments were performed 1 day thereafter. Ovx-allergic rats showed reduced cell recruitment into the bronchoalveolar lavage (BAL) fluid relative to sham-Ovx allergic rats, as was observed in intact allergic rats treated with ICI-182,780. Estradiol increased the number of cells in the BAL of Ovx-allergic rats, whereas progesterone induced an additional reduction. Cells of BAL and bone marrow (BM) of Ovx-allergic rats released elevated amounts of IL-10 and reduced IL-1β and TNF-α. BM cells of Ovx-allergic rats released increased amounts of IL-10 and lower amounts of IL-4. Estradiol treatment of Ovx-allergic rats decreased the release of IL-10 but increased that of IL-4 by BM cells. Estradiol also caused an increased release of IL-1β and TNF-α by BAL cells. Progesterone significantly increased the release of IL-10, IL-1β, and TNF-α by BAL cells and augmented that of IL-4 by BM cells. Degranulation of bronchial mast cells from Ovx rats was reduced after in vitro challenge, an effect reverted by estradiol but not by progesterone. We suggest that the serum estradiol-to-progesterone ratio might drive cellular recruitment, modulating the pulmonary allergy and profile of release of anti-inflammatory or inflammatory cytokines. The existence of such dual hormonal effects suggests that the hormone therapy of asthmatic postmenopausal women and of those suffering of premenstrual asthma should take into account the possibility of worsening the pulmonary conditions.
Descending facilitation of spinal NMDA-dependent reflex potentiation from pontine tegmentum in rats
Authors: Chen Gin-Den , Peng Hsien-Yu , Tung Kwong-Chung , Cheng Chen-Li , Chen Yi-Jui , Liao Jiuan-Miaw , Ho Yu-Cheng , Pan Shwu-Fen , Chen Mei-Jung , Lin Tzer-Bin
Published: July 2007

This study was conducted to investigate whether dorsolateral pontine tegmentum stimulation modulates spinal reflex potentiation (SRP) and whether serotonergic neurotransmission is involved in such a modulation. Reflex activities of the external urethra sphincter (EUS) electromyogram in response to a test stimulation (TS; 1/30 Hz) or repetitive stimulation (RS; 1 Hz) on the pelvic afferent nerve in 35 anesthetized rats were recorded with/without synchronized train pontine stimulation (PS; 300 Hz, 30 ms) and/or intrathecal administrations of 10 μl of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline (NBQX; 100 μM), d-2-amino-5-phosphonovalerate (APV; 100 μM), N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]- N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY 100635; 100 μM), and 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT; 100 μM). The TS evoked a single action potential (1.00 ± 0.00 spikes/stimulation), while the RS produced a long-lasting SRP (16.12 ± 1.59 spikes/stimulation) that was abolished by APV (1.57 ± 0.29 spikes/stimulation) and was attenuated by NBQX (7.42 ± 0.57 spikes/stimulation). Synchronized train PS with RS (PS+RS) produced facilitation in RS-induced SRP (25.17 ± 2.21 spikes/stimulation). Intrathecal WAY 100635 abolished the facilitation in SRP as a result of the synchronized PS (14.66 ± 1.58 spikes/stimulation). On the other hand, intrathecal 8-OH-DPAT elicited facilitation in the RS-induced SRP (25.16 ± 1.05 spikes/stimulation) without synchronized PS. Our findings suggest that dorsolateral pontine tegmentum may modulate N-methyl-d-aspartic acid-dependent SRP via descending serotonergic neurotransmission. This descending modulation may have physiological/pharmacological relevance in the neural controls of urethral closure.
Kidney-specific enhancement of ANG II stimulates endogenous intrarenal angiotensinogen in gene-targeted mice
Authors: Kobori Hiroyuki , Ozawa Yuri , Satou Ryousuke , Katsurada Akemi , Miyata Kayoko , Ohashi Naro , Hase Naoki , Suzaki Yuki , Sigmund Curt D. , Navar L. Gabriel
Published: July 2007

This study was performed in transgenic mice to test the hypothesis that the selective intrarenal overproduction of ANG II increases intrarenal mouse (m) angiotensinogen (AGT) expression. We used the following three groups: 1) single transgenic mice ( group A, n = 14) expressing human (h) AGT only in the kidney, 2) double-transgenic mice ( group D, n = 13) expressing human renin systemically in addition to hAGT only in the kidney, and 3) wild-type ( group W, n = 12) mice. Exogenous hAGT protein is inactive in group A because endogenous mouse renin cannot cleave hAGT to ANG I because of a high species specificity. All mice were monitored from 12 to 18 wk of age. Systolic blood pressure progressively increased from 116 ± 5 mmHg (12 wk) to 140 ± 7 (18 wk) in group D. This increase was not observed in groups A or W. Intrarenal hAGT levels were similar in groups A and D; however, hAGT was not detectable in kidneys of group W. Kidney ANG II levels were increased in group D (216 ± 43 fmol/g) compared with groups A (117 ± 16) and W (118 ± 17). However, plasma ANG II concentrations were similar among the three groups. Endogenous renal mAGT mRNA was increased significantly in group D (1.46 ± 0.19, ratio) compared with groups A (0.97 ± 0.12) and W (1.00 ± 0.08). Endogenous renal mAGT protein was also significantly increased in group D compared with groups A and W. Interstitial collagen-positive area, interstitial macrophage/monocyte infiltration, and afferent arteriolar wall thickness were increased significantly in group D compared with groups A and W. These data indicate for the first time that the selective stimulation of intrarenal production of ANG II from hAGT augments endogenous intrarenal mAGT mRNA and protein expression.
Renal sympathetic nerves modulate erythropoietin plasma levels after transient hemorrhage in rats
Authors: Ditting Tilmann , Hilgers Karl F. , Stetter Alexander , Linz Peter , Schönweiss Christina , Veelken Roland
Published: July 2007

In contrast to other sympathetic outflow tracts, renal sympathetic nerve activity (RSNA) decreases in response to hypotensive hemorrhage. The functional significance of this “paradox” is not known. We tested the hypothesis that RSNA modulates renal perfusion and thus erythropoietin (EPO) release after transient hypotensive hemorrhage in anesthetized rats. Plasma EPO was measured before and after 30 min of transient hypotensive hemorrhage (i.e., −40 mmHg from mean baseline blood pressure, followed by reinfusion of shed blood) and 120 min thereafter in sham-denervated rats, and after renal denervation (DNX) or bilateral cervical vagotomy (VX) to abolish/blunt the RSNA decrease mediated by a cardiopulmonary reflex. RSNA, renal Doppler flow, renal vascular resistance (RVR), resistance index, and oxygen delivery/uptake (Do2/V̇o2) were measured. RSNA decreased in intact animals (−40 ± 5% from baseline, P < 0.05). This was blunted by VX. With intact nerves, EPO level did not increase. In DNX rats, EPO was increased at minute 120 (49 ± 3 vs. 74 ± 2 mU/ml; P < 0.05), in VX rats this (47 ± 2 vs. 62 ± 4 mU/ml; P < 0.05) was less pronounced. Do2 in DNX rats was lower compared with intact and VX rats (0.25 ± 0.04 vs. 0.51 ± 0.06 and 0.54 ± 0.05 ml O2/min; P < 0.05) due to lower Doppler flow and increased RVR. RVR and Do2 were similar in intact and VX rats, but resistance index differed between all groups (0.70 ± 0.02 vs. 0.78 ± 0.02 vs. 0.85 ± 0.02; P < 0.05, intact vs. VX vs. DNX), indicating differential reactivity of renal vasculature. V̇o2 was unaffected by VX and DNX. Renal sympathoinhibition during hypotensive hemorrhage might help to preserve sufficient oxygenation of renal tissue by modulation of hemodynamic mechanisms that act to adapt renal oxygen availability to demand.
Differential Sensitivity of GABAA Receptor-Mediated IPSCs to Cannabinoids in Hippocampal Slices From Adolescent and Adult Rats
Authors: Kang-Park Maeng-Hee , Wilson Wilkie A. , Kuhn Cynthia M. , Moore Scott D. , Swartzwelder H. Scott
Published: July 2007

The impairment of learning and memory is one of the most powerful and least understood effects of marijuana although the hippocampal formation appears to be one CNS region mediating these effects. We have shown that systemic injection of Δ9-tetrahydrocannabinol (THC), an active component of marijuana, impairs spatial learning more efficaciously in adolescent rats, compared with adult rats, but there have been no studies of the cellular mechanisms underlying this developmental sensitivity. In this study, we examined cannabinoid-mediated activity in hippocampal area CA1 neurons in brain slices from adolescent and adult rats. The magnitude of endocannabinoid-mediated synaptic functions such as long-term depression of inhibition was greater in the hippocampal slices from adolescent rats than in those from adults. The effect of R-(+)-(2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1,4-benzoxazine-6-yl)(1-naphtalenyl) methanone mesylate (WIN55,212-2), an exogenous cannabinoid agonist, to suppress GABAA receptor-mediated synaptic responses was also greater in the hippocampal slices from adolescent rats than in those from adults. However, tonic endocannabinoid effects, shown as an increase of the spontaneous IPSC frequency by N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251), a specific CB1 receptor antagonist, were greater in CA1 neurons from adult rats than in those from adolescent rats. On the other hand, WIN55,212-2 suppressed glutamate-mediated excitatory neurotransmission in CA1 pyramidal cells from adolescent and adult rats with similar efficacy. These results indicate that inhibitory synaptic function in the adolescent hippocampus is more sensitive to cannabinoid effects and may account, in part, for the greater sensitivity of adolescent animals to THC-induced memory impairment.
Response Properties and Location of Neurons Selective for Sinusoidal Frequency Modulations in the Inferior Colliculus of the Big Brown Bat
Authors: Yue Qi , Casseday John H. , Covey Ellen
Published: July 2007

Most animal vocalizations, including echolocation signals used by bats, contain frequency-modulated (FM) components. Previous studies have described a class of neurons in the inferior colliculus (IC) of the big brown bat that respond exclusively to sinusoidally frequency modulated (SFM) signals and fail to respond to pure tones, noise, amplitude-modulated tones, or single FM sweeps. The aims of this study were to further characterize these neurons' response properties and to determine whether they are localized within a specific area of the IC. We recorded extracellularly from 214 neurons throughout the IC. Of these, 47 (22%) responded exclusively to SFM. SFM-selective cells were tuned to relatively low carrier frequencies (9–50 kHz), low modulation rates (20–210 Hz), and shallow modulation depths (3–10 kHz). Most had extremely low thresholds, with an average of 16.5 ± 7.6 dB SPL, and 89% had upper thresholds and closed response areas. For SFM-selective cells with spontaneous activity, the spontaneous activity was eliminated when sound amplitude exceeded their upper threshold and resumed after the stimulus was over. These findings suggest that SFM-selective cells receive low-threshold excitatory inputs and high-threshold inhibitory inputs. SFM-selective cells were clustered in the rostrodorsal part of the IC. Within this area, best modulation rate appeared to be correlated with best carrier frequency and depth within the IC.
Muscarinic Receptor–Dependent Long-Term Depression in Rat Visual Cortex Is PKC Independent but Requires ERK1/2 Activation and Protein Synthesis
Authors: McCoy Portia A. , McMahon Lori L.
Published: July 2007

Intact cholinergic innervation of visual cortex is critical for normal processing of visual information and for spatial memory acquisition and retention. However, a complete description of the mechanisms by which the cholinergic system modifies synaptic function in visual cortex is lacking. Previously it was shown that activation of the m1 subtype of muscarinic receptor induces an activity-dependent and partially N-methyl-d-aspartate receptor (NMDAR)-dependent long-term depression (LTD) at layer 4–layer 2/3 synapses in rat visual cortex slices in vitro. The cellular mechanisms downstream of the Gαq coupled m1 receptor required for induction of this LTD (which we term mLTD) are currently unknown. Here, we confirm a role for m1 receptors in mLTD induction and use a series of pharmacological tools to study the signaling molecules downstream of m1 receptor activation in mLTD induction. We found that mLTD is prevented by inhibitors of L-type Ca2+ channels, the Src kinase family, and the mitogen-activated kinase/extracellular kinase. mLTD is also partially dependent on phospholipase C but is unaffected by blocking protein kinase C. mLTD expression can be long-lasting (>2 h) and its long-term maintenance requires translation. Thus we report the signaling mechanisms underlying induction of an m1 receptor-dependent LTD in visual cortex and the requirement of protein synthesis for long-term expression. This plasticity could be a mechanism by which the cholinergic system modifies glutamatergic synapse function to permit normal visual system processing required for cognition.
Pharmacokinetic Investigation of Imatinib Using Accelerator Mass Spectrometry in Patients with Chronic Myeloid Leukemia
Authors: Boddy Alan V. , Sludden Julieann , Griffin Melanie J. , Garner Colin , Kendrick John , Mistry Pritesh , Dutreix Catherine , Newell David R. , O'Brien Stephen G.
Published: July 2007

Purpose: To investigate the potential use of accelerator mass spectrometry (AMS) in the study of the clinical pharmacology of imatinib.

Experimental Design: Six patients who were receiving imatinib (400 mg/d) as part of their ongoing treatment for chronic myeloid leukemia (CML) received a dose containing a trace quantity (13.6 kBq) of 14C-imatinib. Blood samples were collected from patients before and at various times up to 72 h after administration of the test dose and were processed to provide samples of plasma and peripheral blood lymphocytes (PBL). Samples were analyzed by AMS, with chromatographic separation of parent compound from metabolites. In addition, plasma samples were analyzed by liquid chromatography/mass spectrometry (LCMS).

Results: Analysis of the AMS data indicated that imatinib was rapidly absorbed and could be detected in plasma up to 72 h after administration. Imatinib was also detectable in PBL at 24 h after administration of the 14C-labeled dose. Comparison of plasma concentrations determined by AMS with those derived by LCMS analysis gave similar average estimates of area under plasma concentration time curve (26 ± 3 versus 27 ± 11 μg/mL·h), but with some variation within each individual.

Conclusions: Using this technique, data were obtained in a small number of patients on the pharmacokinetics of a single dose of imatinib in the context of chronic dosing, which could shed light on possible pharmacologic causes of resistance to imatinib in CML.
Effect of Cytarabine and Decitabine in Combination in Human Leukemic Cell Lines
Authors: Qin Taichun , Youssef Emile M. , Jelinek Jaroslav , Chen Rong , Yang Allen S. , Garcia-Manero Guillermo , Issa Jean-Pierre J.
Published: July 2007

Purpose: 1-β-d-Arabinofuranosylcytosine (cytarabine; ara-C) is the most active agent in myeloid leukemia. 5-Aza-2′-deoxycytidine (DAC) is a cytosine analogue that inhibits DNA methylation and also has activity in myeloid leukemia. Therefore, we investigated combining these two drugs in human leukemia cell lines in vitro.

Experimental Design: We initially examined the effects of ara-C and DAC on human leukemia cell lines HL60, ML-1, RAji, and Jurkat. We measured IC50 of DAC and ara-C in these cell lines and calculated a combination index of these two drugs given either simultaneously or sequentially. In searching for mechanisms relative to epigenetic regulation for this effect, we examined DNA methylation of LINE and Alu repetitive elements as a surrogate for global genomic DNA methylation. In addition, we sorted Annexin V positive and negative cells and measured differences in LINE methylation between them.

Results: The combination of DAC and ara-C showed additive induction of cell death in ML-1 and synergistic induction in HL60, Raji, and Jurkat. Sequentially, DAC followed by ara-C was a synergistic combination in all cell lines. Low-dose DAC induced more hypomethylation than high doses of the drug, whereas ara-C had no effects on methylation. The combination of ara-C with DAC either together or DAC followed by ara-C resulted in inhibition of LINE demethylation in HL60. The RIL gene, which is silenced by DNA hypermethylation, was activated by DAC, but the addition of ara-C to DAC reduced RIL gene activation. DAC treatment increased H3 Lys9 acetylation of Alu elements, whereas ara-C had no effect, and the addition of ara-C to DAC inhibited this effect. Finally, we showed that after DAC exposure, Annexin V positive cells were more hypomethylated than Annexin V negative cells.

Conclusion: The combination of DAC and ara-C showed additive or synergistic effects on cell death in four human leukemia cell lines in vitro, but antagonism in terms of epigenetic effects. One possible explanation for these paradoxical observations is that hypomethylated cells are sensitized to cell killing by ara-C. These data suggest that DAC used in combination with ara-C has clinical potential in the treatment of acute myeloid leukemia.
Intraperitoneal Injection of a Hairpin RNA–Expressing Plasmid Targeting Urokinase-Type Plasminogen Activator (uPA) Receptor and uPA Retards Angiogenesis and Inhibits Intracranial Tumor Growth in Nude Mice
Authors: Gondi Christopher S. , Lakka Sajani S. , Dinh Dzung H. , Olivero William C. , Gujrati Meena , Rao Jasti S.
Published: July 2007

Purpose: The purpose of this study was to evaluate the therapeutic potential of using plasmid-expressed RNA interference (RNAi) targeting urokinase-type plasminogen activator (uPA) receptor (uPAR) and uPA to treat human glioma.

Experimental Design: In the present study, we have used plasmid-based RNAi to simultaneously down-regulate the expression of uPAR and uPA in SNB19 glioma cell lines and epidermal growth factor receptor (EGFR)–overexpressing 4910 human glioma xenografts in vitro and in vivo, and evaluate the i.p. route for RNAi-expressing plasmid administered to target intracranial glioma.

Results: Plasmid-mediated RNAi targeting uPAR and uPA did not induce OAS1 expression as seen from reverse transcription-PCR analysis. In 4910 EGFR-overexpressing cells, down-regulation of uPAR and uPA induced the down-regulation of EGFR and vascular endothelial growth factor and inhibited angiogenesis in both in vitro and in vivo angiogenic assays. In addition, invasion and migration were inhibited as indicated by in vitro spheroid cell migration, Matrigel invasion, and spheroid invasion assays. We did not observe OAS1 expression in mice with preestablished intracranial tumors, which were given i.p. injections of plasmid-expressing small interfering RNA–targeting uPAR and uPA. Furthermore, the small interfering RNA plasmid targeting uPAR and uPA caused regression of preestablished intracranial tumors when compared with the control mice.

Conclusion: In conclusion, the plasmid-expressed RNAi targeting uPAR and uPA via the i.p. route has potential clinical applications for the treatment of glioma.
TIMP-1 Is Significantly Associated with Objective Response and Survival in Metastatic Colorectal Cancer Patients Receiving Combination of Irinotecan, 5-Fluorouracil, and Folinic Acid
Authors: Sørensen Nanna M. , Byström Per , Christensen Ib J. , Berglund Åke , Nielsen Hans Jørgen , Brünner Nils , Glimelius Bengt
Published: July 2007

Purpose: Tissue inhibitor of metalloproteinase-1 (TIMP-1) is known to protect cells against apoptosis. We raised the hypothesis that elevated tumor tissue levels and thereby plasma levels of TIMP-1 would predict resistance to apoptosis-inducing chemotherapy.

Experimental Design: Ninety patients with metastatic colorectal cancer were included in the study. Plasma TIMP-1 and serum carcinoembryonic antigen (CEA) were measured in samples obtained before the first cycle of chemotherapy.

Results: Analysis of best objective response (complete or partial response versus stable or progressive disease) showed that patients with low plasma TIMP-1 had higher probability of obtaining an objective response [odds ratio (OR), 3.5; 95% confidence interval (95% CI), 1.4-8.5, P = 0.007]. CEA treated as a continuous variable was also a statistically significant predictor of no response (OR, 1.3; 95% CI, 1.0-1.7, P = 0.02, area under the curve 0.66) but much less so. Plasma TIMP-1 was the only significant covariate in a multivariable analysis of best objective response (OR, 3.6; 95% CI, 1.4-9.5; P = 0.001). Plasma TIMP-1 scored as a continuous variable on the log scale (loge) was significantly associated with overall survival [OS; hazard ratio (HR), 3.8; 95% CI, 2.4-5.9; P < 0.0001] and with time to progression (TTP; HR, 1.5; 95% CI, 1.0-2.3; P = 0.048). Multivariable analysis showed that plasma TIMP-1 was significant for OS when including routine clinical baseline covariates (HR, 3.5; 95% CI, 2.1-5.8; P < 0.0001). A multivariable analysis including TTP instead of OS showed that only plasma TIMP-1 was retained in the model (HR, 1.5). CEA was not significantly associated with TTP or OS when TIMP-1 was included in the model.

Conclusion: This study shows that plasma TIMP-1 levels are significantly and independently associated with objective response, TTP, and OS in patients with metastatic colorectal cancer receiving combination chemotherapy.
MDM2 SNP309 Polymorphism as Risk Factor for Susceptibility and Poor Prognosis in Renal Cell Carcinoma
Authors: Hirata Hiroshi , Hinoda Yuji , Kikuno Nobuyuki , Kawamoto Ken , Suehiro Yutaka , Tanaka Yuichiro , Dahiya Rajvir
Published: July 2007

Purpose: MDM2 is a major negative regulator of p53, and a single nucleotide polymorphism in the MDM2 promoter region SNP309 (rs2279744) has been shown to increase the affinity of the transcriptional activator Sp1, resulting in elevated MDM2 transcription and expression in some cancers. There is currently no information about the role of MDM2 polymorphism in renal cell carcinoma (RCC). We investigated polymorphisms in p53-related genes, including MDM2, and their interactions in renal cancer.

Experimental Design: We genotyped three single nucleotide polymorphisms of three genes (p53 Arg72Pro, p21 Ser31Arg, and MDM2 SNP309) in 200 patients with renal cancer and 200 age- and gender-matched healthy subjects. Genotyping was confirmed by direct DNA sequencing. Samples that showed significant polymorphic variants were analyzed for MDM2 expression by immunohistochemistry. Association of polymorphic variants on survival of RCC patients was analyzed by Kaplan-Meier curves.

Results: A significant increase in the GG genotype of the MDM2 SNP309 was observed in RCC patients compared with healthy controls (odds ratio, 1.80; 95% confidence interval, 1.14-2.84). To investigate the effect of the MDM2 SNP309 polymorphism on MDM2 expression, immunohistochemistry was done in genotyped RCC tissues. Positive staining for MDM2 was detected in 2 of 15 (13%) TT genotype, 4 of 15 (26%) TG genotype, and 5 of 10 (50%) GG genotype carriers. The frequency of MDM2 expression in GG genotype carriers was significantly higher than that in TT genotype carriers. Polymorphisms of p53 Arg72Pro and p21 Ser31Arg did not show significant association with RCC. In univariate and multivariate analysis, MDM2 SNP309 GG genotype was independently associated with poor prognosis. Kaplan-Meier curve analysis showed that survival of patients with GG carriers was significantly worse than that of carriers with TG + TT genotypes.

Conclusions: This is the first report to show a significant association between functional polymorphisms in MDM2 and increased risk of developing renal cancer. In addition, the MDM2 polymorphism was shown to be an independent adverse prognostic factor for RCC. Patients with MDM2 309GG genotype showed worse prognosis and low survival.
Plant Species Distributions under Present Conditions and Forecasted for Warmer Climates in an Arid Mountain Range
Authors: Van de Ven Christopher M. , Weiss S. B. , Ernst W. G.
Published: July 2007

Complex environmental gradients in the White and Inyo Mountains in eastern California produce striking variations in vegetation assemblages over short distances. Vegetation composition is dominated by elevational gradients of temperature and precipitation, but local modifications by geologic substrate, potential insolation, slope, and topographic position create finescale mosaics. Digital elevation models, geologic maps, and field data were used to map current species distributions over 6220 km2 (622 000 ha) of the White and Inyo Mountains. Species–environment relationships of 88 plant species were modeled at a scale of 54 m using canonical correspondence analysis (CCA). CCA models were calibrated from 434 field plots and evaluated with 216 plots using kappa statistics. Vegetation responses to temperature increases of 1°–6°C were modeled by shifting species tolerances along the elevational gradient according to a standard lapse rate [3°C (500 m)−1] while all other factors were kept constant. Ranges of midelevations species tended to fragment onto local peaks, whereas the ranges of many desert species merged across a major pass. In several cases, local geologic features were identified as obstacles to species’ upslope migration. As modeled temperatures increase, species contract to small populations around White Mountain Peak (4342 m) and its north-facing slopes. It is predicted that 10 of 18 modeled alpine and subalpine species will become locally extinct if temperatures increase by 6°C. These scenarios provide a detailed set of hypotheses on the structure of current species ranges and their ability to persist through rapid climate change.
Mesoscale Moisture Initialization for Monsoon and Hurricane Forecasts
Authors: Krishnamurti T. N. , Pattnaik S. , Rao D. V. Bhaskar
Published: July 2007

This paper addresses physical initialization of precipitation rates for a mesoscale numerical weather prediction model. This entails a slight modification of the vertical profile of the humidity variable that provides a close match between the satellite and model-based rain rates. This is based on the premise that the rain rate from a cumulus parameterization scheme such as the Arakawa–Schubert scheme is most sensitive to the vertical profiles of moist static stability. It is possible to adjust the vertical profile of moisture by a small linear perturbation by making it wetter (or drier) in the lower levels and the opposite at levels immediately above. This can provide a change in the moist static stability in order to achieve the desired rain rate. The procedure is invoked in a preforecast period between hours −24 and 0 following Krishnamurti et al. The present study is the authors’ first attempt to bring in this feature in a mesoscale model. They first noted that the procedure does indeed provide a much closer match between the satellite estimate of initial rain and that from the physical initialization for a mesoscale model. They have examined the impacts of this procedure for the initialization and short-range forecasts of a monsoon rainfall event and a hurricane. In both of these examples it became possible to improve the forecasts of rains compared with those from control runs that did not include the initialization of rains. Among these two examples, the results for the monsoon forecasts that deployed a uniform resolution of 25 km and the Grell and Devenyi scheme over the entire domain had the largest positive impact. The hurricane forecasts example also show improvement over the control run but with less impact, which may be due to heavy rains from explicit clouds in the nonhydrostatic model. Here the results did convey a strong positive impact from the use of the physical initialization; however, forecasts of very heavy rains carry smaller equitable threat scores. These require development of a more robust precipitation initialization procedure.
Neighborhood Evaluation Using GIS
Authors: Talen Emily , Shah Swasti
Published: July 2007

This article presents a new approach to the investigation of resident views of neighborhood using Geographic Information Systems (GIS). GIS, an interactive mapping and analysis tool, allows multiple layers of information about a given place to be represented simultaneously, thus exposing the interactions among layers, and allows the conception of neighborhood to be represented in greater complexity. The results of a study of the neighborhood evaluations of 18 respondents in Urbana, Illinois, in which GIS was used to facilitate neighborhood evaluation, are described and analyzed. The article first presents an overview of the literature on neighborhood evaluation, followed by a description of the methodology, including a brief overview of GIS capabilities and how GIS was used to elicit responses in a survey of neighborhood residents. A final section summarizes the results of the survey and identifies some of the main findings of the evaluative method.