bluuebunny/crossref_metadata_2025 huggingface dataset:
Looking Forward by Looking Back: May Day Protests in London and the Strategic Significance of the Urban
Authors: Uitermark Justus
Published: September 2004

This paper deals with the question of how oppositional movements can adapt their protest strategies to meet recent socio‐spatial transformations. The work of Lefebvre provides several clues as to how an alternative discourse and appropriation of space could be incorporated in such protest strategies. One of the central themes in Lefebvre's work is that the appearances, forms and functions of urban space are constitutive elements of contemporary capitalism and thus that an alternative narrative of urban space can challenge or undermine dominant modes of thinking. What exactly constitutes the “right” kind of alternative discourse or narrative is a matter of both theoretical and practical consideration. The paper analyses one case: the May Day protests in London in 2001, in which a protest group, the Wombles, managed to integrate theoretical insights into their discourse and practice in a highly innovative manner. Since cities, and global cities in particular, play an ever more important role in maintaining the consumption as well as production practices of global capitalism; they potentially constitute local sites where global processes can be identified and criticised. It is shown that the Wombles effectively made use of these possibilities and appropriated the symbolic resources concentrated in London to exercise a “lived critique” of global capitalism. Since the Wombles capitalised on trends that have not yet ended, their strategies show a way forward for future anti‐capitalist protests.
Object Relations Psychoanalysis as Political Theory
Authors: Gerson Gal
Published: September 2004

This article examines the political contents of object relations psychoanalysis, a theory that perceives dependence as the natural state of all humans. Unlike the views advanced by the classical state‐of‐nature models of Locke, Hobbes, and Rousseau, object relations perceives humans in their original state as already grouped and driven by an urge to associate. Company (rather than privacy, property, or political participation) stands out as the basic right, and all the other rights follow on it as instruments for fulfilling it. The primacy of care lends itself to the justification of distributive measures meant to bolster family cohesion and individual confidence at the expense of the open market. The theory is therefore compatible with the premises of the social‐democratic welfare state.
A sustained response to low dose interferon‐α in a case of refractory pure red cell aplasia
Authors: Nadeau Laura , Meyerson Howard , Warren Gregory , Koç Omer N.
Published: September 2004

Abstract:  Acquired pure red cell aplasia (PRCA) may be the result of a cellular or humoral autoimmune process. One proposed mechanism is the destruction of erythroid progenitors by self‐reactive, cytotoxic T cells or natural killer (NK) cells. These cells normally express MHC class I receptors (KIR) which inhibit cytotoxicity when the target cell expresses the HLA class I antigen(s) they bind. Therefore, loss of these antigens on maturing erythroid progenitors may render them susceptible to destruction by the pathogenic cells. Interferon‐α (INF‐α) increases HLA class I expression on hematopoietic precursor cells. Therefore, we initiated a trial of INF‐α in a patient with refractory PRCA. Following treatment, he developed transfusion independence, and a sustained normal hematocrit. Analysis of bone marrow erythroid cells revealed an increase in expression of HLA class I molecules. INF‐α should be used in a controlled trial in patients with PRCA to determine its activity and mechanism of action.
Bleeding profiles of anticoagulants, including the novel oral direct thrombin inhibitor ximelagatran: definitions, incidence and management
Authors: Bergqvist David
Published: September 2004

Abstract:  Ximelagatran is a novel oral direct thrombin inhibitor (oral DTI) that is currently in advanced clinical development for the prevention and treatment of thromboembolic events in a wide range of patient populations and indications. The clinical development of novel anticoagulant therapies requires that treatments be assessed according to both their clinical benefit (reduction of risk of thromboembolic events) and safety profile (primarily bleeding). Definition and assessment of bleeding severity is thus an important factor in clinical trial design. Lack of consistency in bleeding definitions used in different clinical trial programmes makes comparison of bleeding event data difficult. Standard bleeding definitions would be required to make fair comparisons between clinical trials possible. The definitions of bleeding events used in clinical trials of ximelagatran are broadly consistent with those used in many other major trials. Results of phase II and III trials comparing ximelagatran with currently available anticoagulant therapies demonstrate that ximelagatran can be used with fixed dosing with no coagulation monitoring, dose titration, or dose adjustment, without compromising efficacy or safety. The incidences of major bleeding events in clinical trials of ximelagatran have been low and similar to those with other anticoagulant drugs. Adequate treatment in case of emergency situations such as serious bleeding should include cessation of treatment and maintenance of adequate diuresis.
Relationship between temporomandibular joint dynamics and mouthguards: feasibility of a test method
Authors: Walilko Timothy , Bir Cynthia , Godwin William , King Albert
Published: September 2004

Abstract –  A test system was developed establishing the feasibility of collecting biomechanical data as they relate to the use of mouthguards. Previous experimental studies have examined the physical and mechanical properties of mouthguard materials. This information has been used as a guide for establishing material standards and specifications for the fabrication of mouthguards, but it lacks the key biomechanical parameters required for a thorough mouthguard evaluation. The current study was designed to assess whether the impact force, condylar deflection, and strain superior to the temporomandibular joint region could be measured. A drop test was conducted on a cadaveric specimen to simulate loading at the chin point. To measure the force of impact, an accelerometer was attached to an impactor of known mass. High‐speed biplanar (1000 frames per second) radiographs were used to determine condylar displacement. Radio‐opaque markers were inserted into the bone at predetermined locations. Total displacement of these markers was determined in reference to anatomical landmarks. Strain gauges were attached to the mandible and skull to monitor the effects of the condyle impacting the base of the skull. Based on the data collected, forces were calculated by determining the product of the time‐based acceleration and known mass. A measurable change in force between the mouthguards and the control (no mouthguard) was demonstrated. The average condylar displacement was successfully measured and indicated as an increase in total deflection for impacts conducted with mouthguards. Quantifiable strain was measured in the region above the mandibular fossa with and without the insertion of a mouthguard at all impact conditions. However, it was determined that additional gauges would provide critical data. Key biomechanical parameters for chin‐point impacts were determined in the current study. The technique demonstrated that both displacement within the mandibular fossa and loading of the condyles occur during the impact event. Although the current study established a technique that can be used to examine the relationship between mouthguards and jaw‐joint injuries, the role, if any, mouthguards play in the reduction of injuries cannot be established until a thorough analysis is completed.
Multidisciplinary approach for the rehabilitation of dentoalveolar trauma
Authors: Üstün Yakup , Esen Emin , Toroğlu M. Serdar , Akova Tolga
Published: September 2004

Abstract –  Satisfactory dental rehabilitation of dentoalveolar trauma requires intense effort and time. Usually multidisciplinary treatment planning and teamwork are necessary to deal with multitask problems associated with these cases. Dental implants have been successfully used for replacement of missing teeth, but in trauma cases insufficient alveolar bone hinders implantation. In this report we present the multidisciplinary approach for the treatment of a trauma case. Maxillary segmental alveolar osteotomy in conjunction with interpositional and onlay bone grafting was performed to prepare the site for placement of osseointegrated implants. Titanium microplate and screws were used to provide orthodontic anchorage for intrusion of the extruded mandibular incisors. The patient was rehabilitated by implant supported fixed partial denture 6 months after implant placement.
Getting Students to Provide Direction When Drawing Free-Body Diagrams
Authors: Mattson Mark
Published: September 2004

Free-Body Diagrams (FBDs) are an essential part of teaching mechanics to students in an introductory physics course.1–3 While determining the forces acting on the body is of primary importance,4–6 this paper will not address that issue. Those who are interested in gaining more insight in how to determine the forces that are acting on a body are referred to the work of James E. Court.7,8 In this paper, an extra step in the standard technique is suggested: The student should include the forces' angles in the FBD. Importantly, these angles should be determined relative to appropriate coordinate axes imposed on the system. This step is not emphasized in the textbooks, a general fault for which they have previously been criticized.9,10 It is recommended that students be introduced to this technique after having achieved a reasonable level of mastery in the determination of forces in an FBD.
Identification of Candidate Gammaherpesvirus 68 Genes Required for Virus Replication by Signature-Tagged Transposon Mutagenesis
Authors: Moorman Nathaniel J. , Lin Chie Yu , Speck Samuel H.
Published: September 2004

Current methods for determining the role of a given gene product in the gammaherpesvirus 68 (γHV68) life cycle require generation of a specific mutation by either homologous recombination in mammalian cells or bacterial artificial chromosome-mediated mutagenesis in
Escherichia coli
. The mutant virus is then compared to wild-type virus, and the role of the gene in the viral life cycle is deduced from its phenotype. This process is both time-consuming and labor intensive. Here we present the use of random, transposon-mediated signature-tagged mutagenesis for the identification of candidate viral genes involved in virus replication. Pools of viral mutants, each containing a random insertion of a transposon, were generated with a transposon donor library in which each transposon contains a unique sequence identifier. These pools were transfected into mammalian cells, and the ability of each mutant to replicate was assessed by comparing the presence of virus in the output pool to that present in the input pool of viral genomes. With this approach we could rapidly screen up to 96 individual mutants simultaneously. The location of the transposon insertion was determined by sequencing individual clones with a common primer specific for the transposon end. Here we present the characterization of 53 distinct viral mutants that correspond to insertions in 29 open reading frames within the γHV68 genome. To confirm the results of the signature-tagged mutagenesis screen, we quantitated the ability of each mutant to replicate compared to wild-type γHV68. From these analyses we identified 16 γHV68 open reading frames that, when disrupted by transposon insertions, score as essential for virus replication, and six other open reading frames whose disruption led to significant attenuation of virus replication. In addition, transposon insertion in five other γHV68 open reading frames did not affect virus replication. Notably, all but one of the candidate essential replication genes identified in this screen have been shown to be essential for the replication of at least one other herpesvirus.
Direct Evidence for a Chronic CD8+-T-Cell-Mediated Immune Reaction to Tax within the Muscle of a Human T-Cell Leukemia/Lymphoma Virus Type 1-Infected Patient with Sporadic Inclusion Body Myositis
Authors: Ozden Simona , Cochet Madeleine , Mikol Jacqueline , Teixeira Antonio , Gessain Antoine , Pique Claudine
Published: September 2004

Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) infection can lead to the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), concomitantly with or without other inflammatory disorders such as myositis. These pathologies are considered immune-mediated diseases, and it is assumed that migration within tissues of both HTLV-1-infected CD4+T cells and anti-HTLV-1 cytotoxic T cells represents a pivotal event. However, although HTLV-1-infected T cells were found in inflamed lesions, the antigenic specificity of coinfiltrated CD8+T cells remains to be determined. In this study, we performed both ex vivo and in situ analyses using muscle biopsies obtained from an HTLV-1-infected patient with HAM/TSP and sporadic inclusion body myositis. We found that both HTLV-1-infected CD4+T cells and CD8+T cells directed to the dominant Tax antigen can be amplified from muscle cell cultures. Moreover, we were able to detect in two successive muscle biopsies bothtaxmRNA-positive mononuclear cells and T cells recognized by the Tax11-19/HLA-A*02 tetramer and positive for perforin. These findings provide the first direct demonstration that anti-Tax cytotoxic T cells are chronically recruited within inflamed tissues of an HTLV-1 infected patient, which validates the cytotoxic immune reaction model for the pathogenesis of HTLV-1-associated inflammatory disease.
ORF73 of Herpesvirus Saimiri, a Viral Homolog of Kaposi's Sarcoma-Associated Herpesvirus, Modulates the Two Cellular Tumor Suppressor Proteins p53 and pRb
Authors: Borah Sumit , Verma Subhash C. , Robertson Erle S.
Published: September 2004

All known DNA tumor viruses are known to target and inactivate two main cell cycle regulatory proteins, retinoblastoma protein (pRb) and p53. Inactivation of pRb promotes host cell cycle progression into S phase, and inactivation of p53 promotes cell immortalization. The DNA tumor virus Kaposi's sarcoma associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA) was shown to target and inactivate pRb as well as p53. In this report we provide evidence that these functions are conserved in the homologous protein encoded by the related gammaherpesvirus herpesvirus saimiri (HVS). ORF73, the HVS homologue of LANA, is shown to bind both p53 and pRb in vitro and in vivo, to colocalize with p53 in human T cells infected with HVS, and in cells overexpressing both ORF73 and p53, as well as to adversely influence pRB/E2F and p53 transcriptional regulation. The C terminus of LANA, the region most highly conserved in ORF73, is shown to be responsible for both pRb and p53 interactions, supporting the hypothesis that these functions are conserved in both homologues. Finally, the region of p53 targeted by LANA (and ORF73) maps to the domain required for tetramerization. However, preliminary cross-linking studies do not detect disruption of p53 tetramerization by either LANA or HVS-encoded ORF73, suggesting that p53 inactivation may be by a mechanism independent of tetramer disruption.
Latency-Associated Nuclear Antigen of Kaposi's Sarcoma-Associated Herpesvirus Up-Regulates Transcription of Human Telomerase Reverse Transcriptase Promoter through Interaction with Transcription Factor Sp1
Authors: Verma Subhash C. , Borah Sumit , Robertson Erle S.
Published: September 2004

Telomerase is required for the maintenance of telomere length and is an important determinant for cell immortalization. In human cells, telomerase activity is due to the expression of its enzymatic subunit, human telomerase reverse transcriptase (hTERT). The expression of hTERT is not typically detectable in healthy somatic human cells but is present in cancerous tissues and immortalized cells. We have previously shown that hTERT promoter activity is up-regulated by the Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA). LANA is expressed in all forms of human malignancies associated with KSHV. The hTERT promoter sequence located at positions −130 to +5 contains several Sp1 binding motifs and was shown be important for up-regulation by LANA. In this report, we demonstrate that hTERT promoter activity is due to the direct interaction of LANA with Sp1. The interaction of LANA with Sp1 was demonstrated through in vitro binding experiments and coimmunoprecipitation and is supported by the colocalization of these two molecules in the nuclei of KSHV-infected cells. Moreover, LANA modulates Sp1-mediated transcription in transient GAL4 fusion reporter assays. Mapping of the regions involved in binding and transcriptional activation showed that the amino terminus of LANA is the major site for interaction and up-regulation but that it can cooperate with the carboxy terminus to enhance these functions. An analysis of Sp1 binding to its cognate sequence corroborated the binding data. Together, our results suggest that the interaction of LANA with Sp1 up-regulates the telomerase promoter, potentially contributing to the immortalization of KSHV-infected cells.
Human Cytomegalovirus UL84 Insertion Mutant Defective for Viral DNA Synthesis and Growth
Authors: Xu Yiyang , Cei Sylvia A. , Huete Alicia Rodriguez , Pari Gregory S.
Published: September 2004

Human cytomegalovirus (HCMV) UL84 is required for
ori
Lyt-dependent DNA replication, and evidence from transient transfection assays suggests that UL84 directly participates in DNA synthesis. In addition, because of its apparent interaction with IE2, UL84 is implicated as a possible regulatory protein. To address the role of UL84 in the context of the viral genome, we generated a recombinant HCMV bacterial artificial chromosome (BAC) construct that did not express the UL84 gene product. This construct, BAC-IN84/Ep, displayed a null phenotype in that it failed to produce infectious virus after transfection into human fibroblast cells, whereas a revertant virus readily produced viral plaques and, subsequently, infectious virus. Real-time quantitative PCR showed that BAC-IN84/Ep was defective for DNA synthesis in that no increase in the accumulation of viral DNA was observed in transfected cells. We were unable to complement BAC-IN84/Ep in
trans
; however,
ori
Lyt-dependent DNA replication was observed by the cotransfection of UL84 and BAC-IN84/Ep. An analysis of viral mRNA by real-time PCR indicated that, even in the absence of DNA synthesis, all representative kinetic classes of genes were expressed in cells transfected with BAC-IN84/Ep. The detection of UL44 and IE2 by immunofluorescence in BAC-IN84/Ep-transfected cells showed that these proteins failed to partition into replication compartments, indicating that UL84 expression is essential for the formation of these proteins into replication centers within the context of the viral genome. These results show that UL84 provides an essential DNA replication function and influences the subcellular localization of other viral proteins.
Timing and Reconstruction of the Most Recent Common Ancestor of the Subtype C Clade of Human Immunodeficiency Virus Type 1
Authors: Travers Simon A. A. , Clewley Jonathan P. , Glynn Judith R. , Fine Paul E. M. , Crampin Amelia C. , Sibande Felix , Mulawa Dominic , McInerney James O. , McCormack Grace P.
Published: September 2004

Human immunodeficiency virus type 1 (HIV-1) subtype C is responsible for more than 55% of HIV-1 infections worldwide. When this subtype first emerged is unknown. We have analyzed all available
gag
(p17 and p24) and
env
(C2-V3) subtype C sequences with known sampling dates, which ranged from 1983 to 2000. The majority of these sequences come from the Karonga District in Malawi and include some of the earliest known subtype C sequences. Linear regression analyses of sequence divergence estimates (with four different approaches) were plotted against sample year to estimate the year in which there was zero divergence from the reconstructed ancestral sequence. Here we suggest that the most recent common ancestor of subtype C appeared in the mid- to late 1960s. Sensitivity analyses, by which possible biases due to oversampling from one district were explored, gave very similar estimates.
The Raft-Promoting Property of Virion-Associated Cholesterol, but Not the Presence of Virion-Associated Brij 98 Rafts, Is a Determinant of Human Immunodeficiency Virus Type 1 Infectivity
Authors: Campbell Shahan , Gaus Katharina , Bittman Robert , Jessup Wendy , Crowe Suzanne , Mak Johnson
Published: September 2004

Lipid rafts are enriched in cholesterol and sphingomyelin and are isolated on the basis of insolubility in detergents, such as Brij 98 and Triton X-100. Recent work by Holm et al. has shown that rafts insoluble in Brig 98 can be found in human immunodeficiency virus type 1 (HIV-1) virus-like particles, although it is not known whether raft-like structures are present in authentic HIV-1 and it is unclear whether a virion-associated raft-like structure is required for HIV replication. Independently, it was previously reported that virion-associated cholesterol is critical for HIV-1 infectivity, although the specific requirement of virion cholesterol in HIV-1 was not examined. In the present study, we have demonstrated that infectious wild-type HIV-1 contains Brij 98 rafts but only minimal amounts of Triton X-100 rafts. To directly assess the functional requirement of virion-associated rafts and various features of cholesterol on HIV-1 replication, we replaced virion cholesterol with exogenous cholesterol analogues that have demonstrated either raft-promoting or -inhibiting capacity in model membranes. We observed that variable concentrations of exogenous analogues are required to replace a defined amount of virion-associated cholesterol, showing that structurally diverse cholesterol analogues have various affinities toward HIV-1. We found that replacement of 50% of virion cholesterol with these exogenous cholesterol analogues did not eliminate the presence of Brij 98 rafts in HIV-1. However, the infectivity levels of the lipid-modified HIV-1s directly correlate with the raft-promoting capacities of these cholesterol analogues. Our data provide the first direct assessment of virion-associated Brij 98 rafts in retroviral replication and illustrate the importance of the raft-promoting property of virion-associated cholesterol in HIV-1 replication.
Enhanced Cytoplasmic Sequestration of the Nuclear Export Receptor CRM1 by NS2 Mutations Developed in the Host Regulates Parvovirus Fitness
Authors: López-Bueno Alberto , Valle Noelia , Gallego Jesús M. , Pérez Joel , Almendral José M.
Published: September 2004

To investigate whether a DNA virus can evade passive immunotherapy with a polyclonal antiserum, we analyzed the protection of a neutralizing capsid antiserum against a lethal infection of the immunosuppressive strain of the parvovirus minute virus of mice (MVMi) in 42 immunodeficient mice over a period of 200 days. A few mice were effectively protected, but most developed a delayed lethal leukopenic syndrome during the treatment or weeks afterwards. Unexpectedly, viruses isolated from treated but also from control leukopenic mice showed no amino acid changes throughout the entire capsid coding region, although the viral populations were genetically heterogeneous, mainly in the second exon of the coding sequence of the NS2 nonstructural protein. The NS2 point amino acid changes (T88A, K96E, L103P, and L153 M) that were consistently selected in several mice clustered within the nuclear exportin CRM1 binding domain, in a reading frame that did not alter the overlapping NS1 coding region. These mutations endowed emerging viruses with an increased fitness that was demonstrable by their relative resistance to the neutralizing capsid antiserum in a postentry plaque-forming assay, the rapid overgrowth of a competing wild-type (wt) population in culture, and a larger yield of infectious particles. Mutant NS2 proteins interacted with a higher affinity and sequestered CRM1 in the perinuclear region of the cytoplasm more efficiently than the wt. Correspondingly this phenomenon, as well as the following timely ordered release of the NS1 nonstructural protein and the empty capsid from the nucleus to the cytoplasm, occurred markedly earlier in the infection cycle of the mutant viruses. We hypothesize that the enhanced cytoplasmic sequestration of CRM1 by the NS2 mutations selected in mice may trigger pleiotropic effects leading to an accelerated MVMi life cycle and thus to increased fitness. These results strengthen our earlier report on the rapid evolutionary capacity of this mammalian-specific DNA virus in vivo and indicate that the NS2-CRM1 interaction is an important determinant of parvovirus virulence that can be modulated in nature, hampering the effectiveness of passive antibody therapies in the long term.
Mapping the Golgi Targeting and Retention Signal of Bunyamwera Virus Glycoproteins
Authors: Shi Xiaohong , Lappin David F. , Elliott Richard M.
Published: September 2004

The membrane glycoproteins (Gn and Gc) of
Bunyamwera virus
(BUN; family
Bunyaviridae
) accumulate in the Golgi complex, where virion maturation occurs. The Golgi targeting and retention signal has previously been shown to reside within the Gn protein. A series of truncated Gn and glycoprotein precursor cDNAs were constructed by progressively deleting the coding region of the transmembrane domain (TMD) and the cytoplasmic tail. We also constructed chimeric proteins of BUN Gc, enhanced green fluorescent protein (EGFP), and human respiratory syncytial virus (HRSV) fusion (F) protein that contain the Gn TMD with various lengths of its adjacent cytoplasmic tails. The subcellular localization of mutated BUN glycoproteins and chimeric proteins was investigated by double-staining immunofluorescence with antibodies against BUN glycoproteins or the HRSV F protein and with antibodies specific for the Golgi complex. The results revealed that Gn and all truncated Gn proteins that contained the intact TMD (residues 206 to 224) were able to translocate to the Golgi complex and also rescued the Gc protein, which is retained in the endoplasmic reticulum when expressed alone, to this organelle. The rescued Gc proteins acquired endo-β-
N
-acetylglucosaminidase H resistance. The Gn TMD could also target chimeric EGFP to the Golgi and retain the F protein, which is characteristically expressed on the surface of HRSV-infected cells, in the Golgi. However, chimeric BUN Gc did not translocate to the Golgi, suggesting that an interaction with Gn is involved in Golgi retention of the Gc protein. Collectively, these data demonstrate that the Golgi targeting and retention signal of BUN glycoproteins resides in the TMD of the Gn protein.
A Riboswitch Regulates RNA Dimerization and Packaging in Human Immunodeficiency Virus Type 1 Virions
Authors: Ooms Marcel , Huthoff Hendrik , Russell Rodney , Liang Chen , Berkhout Ben
Published: September 2004

The genome of retroviruses, including human immunodeficiency virus type 1 (HIV-1), consists of two identical RNA strands that are packaged as noncovalently linked dimers. The core packaging and dimerization signals are located in the downstream part of the untranslated leader of HIV-1 RNA—the Ψ and the dimerization initiation site (DIS) hairpins. The HIV-1 leader can adopt two alternative conformations that differ in the presentation of the DIS hairpin and consequently in their ability to dimerize in vitro. The branched multiple-hairpin (BMH) structure folds the poly(A) and DIS hairpins, but these domains are base paired in a long distance interaction (LDI) in the most stable LDI conformation. This LDI-BMH riboswitch regulates RNA dimerization in vitro. It was recently shown that the Ψ hairpin structure is also presented differently in the LDI and BMH structures. Several detailed in vivo studies have indicated that sequences throughout the leader RNA contribute to RNA packaging, but how these diverse mutations affect the packaging mechanism is not known. We reasoned that these effects may be due to a change in the LDI-BMH equilibrium, and we therefore reanalyzed the structural effects of a large set of leader RNA mutations that were presented in three previous studies (J. L. Clever, D. Mirandar, Jr., and T. G. Parslow, J. Virol.
76:
12381-12387, 2002; C. Helga-Maria, M. L. Hammarskjold, and D. Rekosh, J. Virol.
73:
4127-4135, 1999; R. S. Russell, J. Hu, V. Beriault, A. J. Mouland, M. Laughrea, L. Kleiman, M. A. Wainberg, and C. Liang, J. Virol.
77:
84-96, 2003). This analysis revealed a strict correlation between the status of the LDI-BMH equilibrium and RNA packaging. Furthermore, a correlation is apparent between RNA dimerization and RNA packaging, and these processes may be coordinated by the same LDI-BMH riboswitch mechanism.
Profibrotic influence of high glucose concentration on cardiac fibroblast functions: effects of losartan and vitamin E
Authors: Asbun Juan , Manso Ana Maria , Villarreal Francisco J.
Published: September 2004

Long-standing diabetes can result in the development of cardiomyopathy, which can be accompanied by myocardial fibrosis. Although exposure of cultured kidney and skin fibroblasts to high glucose (HG) concentration is known to increase collagen synthesis, little is known about cardiac fibroblasts (CFs). Therefore, we determined the influence of HG conditions on CF functions and the effects of losartan and vitamin E in these responses. We cultured rat CFs in either normal glucose (NG; 5.5 mM) or HG (25 mM) media and assessed changes in protein and collagen synthesis, matrix metalloproteinase (MMP) activity, and levels of mRNA for ANG II type 1 (AT1) receptors. Results indicate that HG-level CFs synthesized more protein and collagen, and these effects were not due to changes in osmotic pressure. The addition of ANG II stimulated protein and collagen synthesis in NG-concentration but not HG-concentration CFs. Interestingly, losartan pretreatment blocked the HG- or ANG II-induced increases in both protein and collagen synthesis. HG or ANG II decreased total MMP activity. Decreases in MMP activity were blocked by losartan. AT1 mRNA levels were upregulated with HG concentration. Vitamin E pretreatment blocked the effects of HG on total protein synthesis and stimulated MMP activity. Results suggest that HG levels may promote fibrosis by increasing CF protein and collagen synthesis and decreasing MMP activity. HG levels may cause these effects via the upregulation of AT1 receptors, which can be blocked by losartan. However, vitamin E can alter HG concentration-induced changes in CF functions independently of AT1 mRNA levels.
Pharmacological preconditioning with resveratrol: role of CREB-dependent Bcl-2 signaling via adenosine A3 receptor activation
Authors: Das Samarjit , Cordis Gerald A. , Maulik Nilanjana , Das Dipak K.
Published: September 2004

Recent studies demonstrated that resveratrol, a grape-derived polyphenolic phytoalexin, provides pharmacological preconditioning (PC) of the heart through a NO-dependent mechanism. Because adenosine receptors play a role in PC, we examined whether they play any role in resveratrol PC. Rats were randomly assigned to groups perfused for 15 min with 1) Krebs-Henseleit bicarbonate buffer (KHB) only; 2) KHB containing 10 μM resveratrol; 3) 10 μM resveratrol + 1 μM 8-cyclopentyl-1,3-dimethylxanthine (CPT; adenosine A1 receptor blocker); 4) 10 μM resveratrol + 1 μM 8-(3-chlorostyryl)caffeine (CSC; adenosine A2a receptor blocker); 5) 10 μM resveratrol + 1 μM 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS-1191; adenosine A3 receptor blocker); or 6) 10 μM resveratrol + 3 μM 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride [LY-294002, phosphatidylinositol (PI)3-kinase inhibitor], and groups perfused with adenosine receptor blockers alone. Hearts were then subjected to 30-min ischemia followed by 2-h reperfusion. The results demonstrated significant cardioprotection with resveratrol evidenced by improved ventricular recovery and reduced infarct size and cardiomyocyte apoptosis. CPT and MRS 1191, but not CSC, abrogated the cardioprotective abilities of resveratrol, suggesting a role of adenosine A1 and A3 receptors in resveratrol PC. Resveratrol induced expression of Bcl-2 and caused its phosphorylation along with phosphorylation of cAMP response element-binding protein (CREB), Akt, and Bad. CPT blocked phosphorylation of Akt and Bad without affecting CREB, whereas MRS 1191 blocked phosphorylation of all compounds, including CREB. LY-294002 partially blocked the cardioprotective abilities of resveratrol. The results indicate that resveratrol preconditions the heart through activation of adenosine A1 and A3 receptors, the former transmitting a survival signal through PI3-kinase-Akt-Bcl-2 signaling pathway and the latter protecting the heart through a CREB-dependent Bcl-2 pathway in addition to an Akt-Bcl-2 pathway.
Effects of sodium nitroprusside in aortic stenosis associated with severe heart failure: pressure-volume loop analysis using a numerical model
Authors: Popović Zoran B. , Khot Umesh N. , Novaro Gian M. , Casas Fernando , Greenberg Neil L. , Garcia Mario J. , Francis Gary S. , Thomas James D.
Published: September 2004

In the recently published clinical study [Use of Nitroprusside in Left Ventricular Dysfunction and Obstructive Aortic Valve Disease (UNLOAD)], sodium nitroprusside (SNP) improved cardiac function in patients with severe aortic stenosis (AS) and left ventricular (LV) systolic dysfunction. We explored the possible mechanisms of these findings using a series of numerical simulations. A closed-loop lumped parameters model that consists of 24 differential equations relating pressure and flow throughout the circulation was used to analyze the effects of varying hemodynamic conditions in AS. Hemodynamic data from UNLOAD study subjects were used to construct the initial simulation. Systemic vascular resistance (SVR), heart rate, and aortic valve area were directly entered into the model while end-systolic and end-diastolic pressure-volume (P-V) relationships were adjusted using previously published data to match modeled and observed end-systolic and end-diastolic pressures and volumes. Initial simulation of SNP treatment by a reduction of SVR was not adequate. To obtain realistic model hemodynamics that reliably reproduce SNP treatment effects, we performed a series of simulations while simultaneously changing end-systolic elastance ( Ees), end-systolic volume at zero pressure (V0), and diastolic P-V shift. Our data indicate that either an Ees increase or V0 decrease is necessary to obtain realistic model hemodynamics. In five patients, we corroborated our findings by using the model to duplicate individual P-V loops obtained before and during SNP treatment. In conclusion, using a numerical model, we identified ventricular function parameters that are responsible for improved hemodynamics during SNP infusion in AS with LV dysfunction.
Proteomic identification of 3-nitrotyrosine-containing rat cardiac proteins: effects of biological aging
Authors: Kanski Jaroslaw , Behring Antje , Pelling Jill , Schöneich Christian
Published: September 2004

Proteomic techniques were used to identify cardiac proteins from whole heart homogenate and heart mitochondria of Fisher 344/Brown Norway F1 rats, which suffer protein nitration as a consequence of biological aging. Soluble proteins from young (5 mo old) and old (26 mo old) animals were separated by one- and two-dimensional gel electrophoresis. One- and two-dimensional Western blots with an anti-nitrotyrosine antibody show an age-related increase in the immunoresponse of a few specific proteins, which were identified by nanoelectrospray ionization-tandem mass spectrometry (NSI-MS/MS). Complementary proteins were immunoprecipitated with an immobilized anti-nitrotyrosine antibody followed by NSI-MS/MS analysis. A total of 48 proteins were putatively identified. Among the identified proteins were α-enolase, α-aldolase, desmin, aconitate hydratase, methylmalonate semialdehyde dehydrogenase, 3-ketoacyl-CoA thiolase, acetyl-CoA acetyltransferase, GAPDH, malate dehydrogenase, creatine kinase, electron-transfer flavoprotein, manganese-superoxide dismutase, F1-ATPase, and the voltage-dependent anion channel. Some contaminating blood proteins including transferrin and fibrinogen β-chain precursor showed increased levels of nitration as well. MS/MS analysis located nitration at Y105 of the electron-transfer flavoprotein. Among the identified proteins, there are important enzymes responsible for energy production and metabolism as well as proteins involved in the structural integrity of the cells. Our results are consistent with age-dependent increased oxidative stress and with free radical-dependent damage of proteins. Possibly the oxidative modifications of the identified proteins contribute to the age-dependent degeneration and functional decline of heart proteins.
PPAR-γ agonist rosiglitazone ameliorates ventricular dysfunction in experimental chronic mitral regurgitation
Authors: Nemoto Shintaro , Razeghi Peter , Ishiyama Masakuni , De Freitas Gilberto , Taegtmeyer Heinrich , Carabello Blase A.
Published: September 2004

Previously we reported that the beneficial effects of β-adrenergic blockade in chronic mitral regurgitation (MR) were in part due to induction of bradycardia, which obviously affects myocardial energy requirements. From this observation we hypothesized that part of the pathophysiology of MR may involve faulty energy substrate utilization, which in turn might lead to potentially harmful lipid accumulation as observed in other models of heart failure. To explore this hypothesis, we measured triglyceride accumulation in the myocardia of dogs with chronic MR and then attempted to enhance myocardial metabolism by chronic administration of the peroxisome proliferator-activated receptor (PPAR)-γ agonist rosiglitazone. Cardiac tissues were obtained from three groups of dogs that included control animals, dogs with MR for 3 mo without treatment, and dogs with MR for 6 mo that were treated with rosiglitazone (8 mg/day) for the last 3 mo of observation. Hemodynamics and contractile function (end-systolic stress-strain relationship, as measured by K index) were assessed at baseline, 3 mo of MR, and 6 mo of MR (3 mo of the treatment). Lipid accumulation in MR (as indicated by oil red O staining score and TLC analysis) was marked and showed an inverse correlation with the left ventricular (LV) contractility. LV contractility was significantly restored after PPAR therapy (K index: therapy, 3.01 ± 0.11*; 3 mo MR, 2.12 ± 0.34; baseline, 4.01 ± 0.29; ANOVA, P = 0.038; * P < 0.05 vs. 3 mo of MR). At the same time, therapy resulted in a marked reduction of intramyocyte lipid. We conclude that 1) chronic MR leads to intramyocyte myocardial lipid accumulation and contractile dysfunction, and 2) administration of the PPAR-γ agonist rosiglitazone ameliorates MR-induced LV dysfunction accompanied by a decline in lipid content.
Nitric Oxide–Releasing Aspirin Derivative, NCX 4016, Promotes Reparative Angiogenesis and Prevents Apoptosis and Oxidative Stress in a Mouse Model of Peripheral Ischemia
Authors: Emanueli Costanza , Van Linthout Sophie , Salis Maria Bonaria , Monopoli Angela , Del Soldato Piero , Ongini Ennio , Madeddu Paolo
Published: September 2004

Background—

Recently, nitric oxide (NO) donors have been developed that mimic the physiological intracellular release of NO. We evaluated whether one of these new compounds, consisting of aspirin coupled to an NO-releasing moiety (NCX 4016), would protect limbs from supervening arterial occlusion.

Methods and Results—

Mice were assigned to receive regular chow or chow containing NCX 4016 or aspirin (both at 300 μmol/kg body weight, daily) throughout the 3-week experimental period. One week after randomization, they underwent surgical excision of the left femoral artery. Limb blood flow recovery (laser Doppler flowmetry) was accelerated by NCX 4016 as compared with aspirin or vehicle (
P
<0.05). In controls, histological analysis revealed a 35% increase in the capillary density of ischemic muscles compared with contralateral ones, indicative of spontaneous angiogenesis. Neovascularization was enhanced by NCX 4016 (91%;
P
<0.05 versus vehicle), but not by aspirin (51%;
P
=NS versus vehicle). Furthermore, NCX 4016 reduced endothelial cell (EC) apoptosis (4.3±1.0 versus 8.7±2.0 in aspirin and 12.6±3.3 ECs/1000 cap in vehicle;
P
<0.05 for either comparison) as well as
caspase-3
mRNA levels in ischemic muscles ([caspase-3/GAPDH]*100 = 0.09±0.04 versus 2.30±0.44 in aspirin and 2.30±0.32 in vehicle;
P
<0.01 for either comparison). Nitrite levels and the ratio of reduced to oxidized glutathione were selectively increased in ischemic muscles by NCX 4016. Vascular endothelial growth factor-A expression was reduced by aspirin, with this effect being blunted by NCX 4016.

Conclusions—

Pretreatment with the new oral NO-releasing aspirin derivative stimulates reparative angiogenesis and prevents apoptosis and oxidative stress, thereby alleviating the consequences of supervening arterial occlusion.
Cardiac Specific Increase in Aldosterone Production Induces Coronary Dysfunction in Aldosterone Synthase–Transgenic Mice
Authors: Garnier Anne , Bendall Jennifer K. , Fuchs Sebastien , Escoubet Brigitte , Rochais Francesca , Hoerter Jacqueline , Nehme Johnny , Ambroisine Marie-Lory , De Angelis Noeleen , Morineau Gilles , d’Estienne Pauline , Fischmeister Rodolphe , Heymes Christophe , Pinet Florence , Delcayre Claude
Published: September 2004

Background—

Elevated circulating aldosterone level is associated with impaired cardiovascular function. Although the mechanisms are not fully understood, aldosterone antagonists decrease total and cardiovascular mortality in heart failure and myocardial infarction. Aldosterone induces cardiac fibrosis in experimental models, and it is synthesized locally in rat heart. These observations suggest pathological effects of aldosterone in heart that remain unclear.

Methods and Results—

Transgenic mice (TG) that overexpress the terminal enzyme of aldosterone biosynthesis, aldosterone synthase (AS), in heart have been raised by gene targeting with the α-myosin heavy chain promoter. AS mRNA increased 100-fold and aldosterone concentration 1.7-fold in hearts of male TG mice relative to wild-type. No structural or myocardial alterations were evidenced, because ventricle/body weight, AT
1
and AT
2
receptor binding, and collagen content were unchanged in TG. No alteration in cardiac function was evidenced by echocardiography, isolated perfused heart, or whole-cell patch clamp experiments. In contrast, coronary function was impaired, because basal coronary flow was decreased in isolated perfused heart (−55% of baseline values), and vasodilatation to acetylcholine, bradykinin, and sodium nitroprusside was decreased by 75%, 60%, and 75%, respectively, in TG mice compared with wild-type, showing that the defect was not related to NO production.

Conclusions—

Increased cardiac aldosterone production in male mice induces a major coronary endothelium-independent dysfunction with no detectable alterations in cardiac structure and function. However, coronary dysfunction may be harmful for coronary adaptation to increased flow demand.
Effect of Aging and Physical Activity on Left Ventricular Compliance
Authors: Arbab-Zadeh Armin , Dijk Erika , Prasad Anand , Fu Qi , Torres Pilar , Zhang Rong , Thomas James D. , Palmer Dean , Levine Benjamin D.
Published: September 2004

Background—

Left ventricular compliance appears to decrease with aging, which may contribute to the high incidence of heart failure in the elderly. However, whether this change is an inevitable consequence of senescence or rather secondary to reduced physical activity is unknown.

Methods and Results—

Twelve healthy sedentary seniors (69.8±3 years old; 6 women, 6 men) and 12 Masters athletes (67.8±3 years old; 6 women, 6 men) underwent pulmonary artery catheterization to define Starling and left ventricular pressure-volume curves. Data were compared with those obtained in 14 young but sedentary control subjects (28.9±5 years old; 7 women, 7 men). Pulmonary capillary wedge pressures and left ventricular end-diastolic volumes by use of echocardiography were measured at baseline, during decreased cardiac filling by use of lower-body negative pressure (−15 and −30 mm Hg), and after saline infusion (15 and 30 mL/kg). Stroke volume for any given filling pressure was greater in Masters athletes compared with the age-matched sedentary subjects, whereas contractility, as assessed by preload recruitable stroke work, was similar. There was substantially decreased left ventricular compliance in healthy but sedentary seniors compared with the young control subjects, which resulted in higher cardiac pressures for a given filling volume and higher myocardial wall stress for a given strain. The pressure-volume curve for the Masters athletes was indistinguishable from that of the young, sedentary control subjects.

Conclusions—

A sedentary lifestyle during healthy aging is associated with decreased left ventricular compliance, leading to diminished diastolic performance. Prolonged, sustained endurance training preserves ventricular compliance with aging and may help to prevent heart failure in the elderly.
Effect of Pravastatin on Cardiovascular Events in People With Chronic Kidney Disease
Authors: Tonelli Marcello , Isles Chris , Curhan Gary C. , Tonkin Andrew , Pfeffer Marc A. , Shepherd James , Sacks Frank M. , Furberg Curt , Cobbe Stuart M. , Simes John , Craven Timothy , West Malcolm
Published: September 2004

Background—

Limited data describe the cardiovascular benefit of HMG-CoA reductase inhibitors (statins) in people with moderate chronic kidney disease (CKD). The objective of this analysis was to determine whether pravastatin reduced the incidence of cardiovascular events in people with or at high risk for coronary disease and with concomitant moderate CKD.

Methods and Results—

We analyzed data from the Pravastatin Pooling Project (PPP), a subject-level database combining results from 3 randomized trials of pravastatin (40 mg daily) versus placebo. Of 19 700 subjects, 4491 (22.8%) had moderate CKD, defined by an estimated glomerular filtration rate of 30 to 59.99 mL/min per 1.73 m
2
body surface area. The primary outcome was time to myocardial infarction, coronary death, or percutaneous/surgical coronary revascularization. Moderate CKD was independently associated with an increased risk of the primary outcome (adjusted HR 1.26, 95% CI 1.07 to 1.49) compared with those with normal renal function. Among the 4491 subjects with moderate CKD, pravastatin significantly reduced the incidence of the primary outcome (HR 0.77, 95% CI 0.68 to 0.86), similar to the effect of pravastatin on the primary outcome in subjects with normal kidney function (HR 0.78, 95% CI 0.65 to 0.94). Pravastatin also appeared to reduce the total mortality rate in those with moderate CKD (adjusted HR 0.86, 95% CI 0.74 to 1.00,
P
=0.045).

Conclusions—

Pravastatin reduces cardiovascular event rates in people with or at risk for coronary disease and concomitant moderate CKD, many of whom have serum creatinine levels within the normal range. Given the high risk associated with CKD, the absolute benefit that resulted from use of pravastatin was greater than in those with normal renal function.