bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time‐courses of perfusion and phosphocreatine in rat leg during low‐level exercise and recovery
Authors: Marro Kenneth I. , Olive Jennifer L. , Hyyti Outi M. , Kushmerick Martin J. 
Published: April 2007

AbstractPurposeTo develop a noninvasive protocol for measuring local perfusion and metabolic demand in muscle tissue with sufficient sensitivity and time resolution to monitor kinetics at the onset of low‐level exercise and during recovery.Materials and MethodsCapillary‐level perfusion, the critical factor that determines oxygen and substrate delivery to active muscle, was measured by an arterial spin labeling (ASL) technique optimized for skeletal muscle. Phosphocreatine (PCr) kinetics, which signal the flux of oxidative phosphorylation, were measured by 31P MR spectroscopy. Perfusion and PCr measurements were made in parallel studies before, during, and after three different intensities of low‐level, stimulated exercise in rat hind limb.ResultsThe data reveal close coupling between the perfusion response and PCr changes. The onset and recovery time constants for PCr changes were independent of contractile force over the range of forces studied. Perfusion time constants during both onset of exercise and recovery tended to increase with contractile force.ConclusionThese results demonstrate that the protocol implemented can be useful for probing the mechanisms that control skeletal muscle blood flow, the physiological limits to muscle performance, and the causes for the attenuated exercise‐induced hyperemia observed in disease states. J. Magn. Reson. Imaging 2007;25:1021–1027. © 2007 Wiley‐Liss, Inc.
Optimal acquisition orders of diffusion‐weighted MRI measurements
Authors: Cook Philip A. , Symms Mark , Boulby Philip A. , Alexander Daniel C. 
Published: April 2007

AbstractPurposeTo propose a new method to optimize the ordering of gradient directions in diffusion‐weighted MRI so that partial scans have the best spherical coverage.Materials and MethodsDiffusion‐weighted MRI often uses a spherical sampling scheme, which acquires images sequentially with diffusion‐weighting gradients in unique directions distributed isotropically on the hemisphere. If not all of the measurements can be completed, the quality of diffusion tensors fitted to the partial scan is sensitive to the order of the gradient directions in the scanner protocol. If the directions are in a random order, then a partial scan may cover some parts of the hemisphere densely but other parts sparsely and thus provide poor spherical coverage. We compare the results of ordering with previously published methods for optimizing the acquisition in simulation.ResultsResults show that all methods produce similar results and all improve the accuracy of the estimated diffusion tensors significantly over unordered acquisitions.ConclusionThe new ordering method improves the spherical coverage of partial scans and has the advantage of maintaining the optimal coverage of the complete scan. J. Magn. Reson. Imaging 2007;25:1051–1058. © 2007 Wiley‐Liss, Inc.
MR contrast agents: Physical and pharmacologic basics
Authors: Lin Shao‐Pow , Brown Jeffrey J. 
Published: April 2007

AbstractSince approval of the first magnetic resonance (MR) contrast agent was granted in 1988, there has been remarkable growth in the utilization of intravenous gadolinium (Gd)‐based agents. Currently it is estimated that nearly half of all MR studies performed are contrast‐enhanced. Despite containing a toxic heavy metal, these agents have proven to be not only an effective diagnostic adjunct to non‐enhanced MRI, but also remarkably well tolerated and safe. As a result, conventional wisdom has been that MR contrast media are “biologically inert,” a notion that is clearly false. Ultimately, it is the radiologist's responsibility to understand the potential adverse effects of Gd‐based agents and the special situations in which they are likely to occur; however, the basic pharmacology of contrast agents is generally not included in medical school curricula or formally taught in residency. The purpose of this review is to discuss the mechanism of action of MR contrast agents and relevant aspects of their clinical pharmacology, including effects on the cardiovascular and renal systems, potential laboratory errors, and special situations involving women and children. We also briefly discuss the issue of nephrogenic systemic fibrosis (NSF). J. Magn. Reson. Imaging 2007;25:884–899. © 2007 Wiley‐Liss, Inc.
Human papillomavirus genotypes associated with cervical cytologic abnormalities and HIV infection in Ugandan women
Authors: Blossom D.B. , Beigi R.H. , Farrell J.J. , Mackay W. , Qadadri B. , Brown D.R. , Rwambuya S. , Walker C.J. , Kambugu F.S. , Abdul‐Karim F.W. , Whalen C.C. , Salata R.A. 
Published: April 2007

AbstractHuman papillomavirus (HPV) infection is associated with almost all cases of cervical cancer, and cervical cancer is a common malignancy in women living in developing countries. A cross‐sectional study was conducted to determine the prevalence of HPV infection, human immunodeficiency virus (HIV) infection, and cervical cytologic abnormalities in women presenting to a sexually transmitted infections clinic in Kampala, Uganda. In June and July, 2002, 135 women underwent complete physical exams including Papanicolaou (Pap) smears. HIV status was evaluated by serology. Cervical and vaginal swabs were obtained by clinicians and tested for HPV genotypes by PCR/reverse blot strip assay. Of the 106 women with cervical swabs adequate for HPV testing, the HPV prevalence was 46.2% (49/106). HIV prevalence was 34.9% (37/106). High risk genotypes 52, 58, and 16 were the genotypes detected most commonly. Eighteen percent (9/49) of women infected with HPV were found to have genotypes 16 and/or 18. Seventy‐three percent (27/37) of HIV‐positive women versus 16% (10/63) of HIV‐negative women had abnormal Pap smears (P < 0.0001). Among HIV‐positive women, abnormal Pap smears were associated with the presence of high risk HPV genotypes (P < 0.001). The majority of women infected with HPV attending this sexually transmitted infections clinic in Uganda were infected with high risk HPV genotypes other than 16 and 18. Future studies should focus on whether current HPV vaccine formulations, that are limited to high risk genotypes 16 and 18, would be effective at decreasing the burden of cervical cancer in this population. J. Med. Virol. 79: 758–765, 2007. © 2007 Wiley‐Liss, Inc.
The roles of CD81 and glycosaminoglycans in the adsorption and uptake of infectious HCV particles
Authors: Morikawa Kenichi , Zhao Zijiang , Date Tomoko , Miyamoto Michiko , Murayama Asako , Akazawa Daisuke , Tanabe Junichi , Sone Saburo , Wakita Takaji 
Published: April 2007

AbstractBecause appropriate cell‐culture systems or small‐animal models have been lacking, the early steps in the HCV life cycle have been difficult to study. A cell culture system was developed recently that allows production of infectious HCV. In this study, infectious HCV particles produced in cultured cells were used. To clarify the role of CD81 in HCV attachment and entry, the effect of anti‐CD81 antibody was examined. The antibody blocked HCV virion entry but not particle attachment. Only the fraction bound to a heparin affinity column and eluted with 0.3 M NaCl productively infected Huh7 cells, indicating that infectious HCV particles bind to heparin. Both heparin treatment of the virus particles and heparinase treatment of the Huh7 cells reduced virus‐cell binding without substantially inhibiting HCV infectivity. Finally, to confirm the role of both heparin sulfate proteoglycan (HSPG) and CD81 in HCV entry, the effects of heparinase I and anti‐CD81 antibody were analyzed. No productive RNA replication was detected in the Huh7 cells in the presence of both heparinase I and anti‐CD81 antibody. In conclusion, these data suggested that both HSPG and CD81 are important for HCV entry. HSPG may play a role in the initial cell surface binding of infectious HCV particles and CD81 is conceivably correlated with HCV entry after viral attachment. J. Med. Virol. 79: 714–723, 2007. © 2007 Wiley‐Liss, Inc.
Antiretroviral drug resistance and phylogenetic diversity of HIV‐1 in Chile
Authors: Ríos Maritza , Delgado Elena , Pérez‐Álvarez Lucía , Fernández Jorge , Gálvez Paula , de Parga Elena Vázquez , Yung Verónica , Thomson Michael M. , Nájera Rafael 
Published: April 2007

AbstractThis study reports the analysis of human immunodeficiency virus type 1 (HIV‐1) protease (PR) and reverse transcriptase (RT) coding sequences from 136 HIV‐1‐infected subjects from Chile, 66 (49%) of them under antiretroviral (ARV) treatment. The prevalence of mutations conferring high or intermediate resistance levels to ARVs was 77% among treated patients and 2.5% among drug‐naïve subjects. The distribution of resistance prevalence in treated patients by drug class was 61% to nucleoside RT inhibitors, 84% to nonnucleoside RT inhibitors, and 46% to PR inhibitors. Phylogenetic analysis revealed that 115 (85%) subjects were infected with subtype B viruses, 1 with a subtype F1 virus, and 20 (15%) carried BF intersubtype recombinants. Most BF recombinants grouped into two clusters, one related to CRF12_BF, while the other could represent a new circulating recombinant form (CRF). In conclusion, this is the first report analysing the prevalence of ARV resistance which includes patients under HAART from Chile. Additionally, phylogenetic analysis of the PR–RT coding sequences reveals the presence of BF intersubtype recombinants. J. Med. Virol. 79: 647–656, 2007. © 2007 Wiley‐Liss, Inc.
Mother‐to‐infant transmission of multiple blood‐borne viral infections from multi‐infected mothers
Authors: Indolfi Giuseppe , Moriondo Maria , Galli Luisa , Azzari Chiara , Poggi Giovanni Maria , Resti Massimo , de Martino Maurizio 
Published: April 2007

AbstractInfants born from mothers with multiple blood‐borne viral infections are at risk of multiple transmissions. Whether the risk of transmission of multiple infections increases with the number of viruses infecting the mother is still unknown. The aim of this study was to describe the risk of mother‐to‐infant transmission of multiple infections from multi‐infected mothers. Sixty‐four pregnant women infected by at least two viruses among human immunodeficiency virus‐type 1 (HIV‐1), hepatitis C virus, TT virus, and GB virus type C, together with their 64 infants, were studied. Maternal blood samples were collected in the third trimester of pregnancy and all infants were prospectively followed for evaluation of transmission within 3 months after birth and two times in the subsequent 24 months. Transmission of single and of dual infection from mothers infected by two viruses was, respectively, 10/40 (25%) and 5/40 (12.5%) and from mothers infected by three viruses 9/20 (45%) and 2/20 (10%). One (25%) infant infected by one virus was born from the four mothers infected by four viruses. Transmission of single or dual infection was not significantly associated with the number of viruses infecting the mother (P = 0.9) in the linear regression analysis. Present study suggests the absence of a synergistic effect from viral interactions toward mother‐to‐infant transmission of multiple infections and supports the hypothesis that transmission from multi‐infected mothers is the result of the specific interaction between each virus and the host. These observations may be of clinical relevance in perinatal counseling. J. Med. Virol. 79: 743–747, 2007. © 2007 Wiley‐Liss, Inc.
Transplacental infection of coxsackievirus B3 pathological findings in the fetus
Authors: Konstantinidou Anastasia , Anninos Hector , Spanakis Nikolaos , Kotsiakis Xenophon , Syridou Garyfallia , Tsakris Athanassios , Patsouris Efstratios 
Published: April 2007

AbstractCoxsackievirus intrauterine infection has been documented mostly on the basis of indirect evidence of transplacental transmission, with neonatal manifestations ranging from asymptomatic infection to meningoencephalitis, myocarditis, and generalized sepsis. This is the first report of prenatal findings and fetoplacental pathology in a third trimester fetus with coxsackie B3 transplacental infection confirmed by molecular techniques. Prenatal ultrasound detected severe reduction of fetal movements at the 27th week. Late onset fetal akinesia deformation sequence with mild arthrogryposis, necrotic meningoencephalitis with vascular calcifications, interstitial pneumonitis, mild myocardial hypertrophy, and chronic monocytic placental villitis were the cardinal findings at fetal autopsy following interruption of the pregnancy. J. Med. Virol. 79: 754–757, 2007. © 2007 Wiley‐Liss, Inc.
Viral load and genomic integration of HPV 16 in cervical samples from HIV‐1‐infected and uninfected women in Burkina Faso
Authors: Rousseau Marie‐Noelle Didelot , Costes Valérie , Konate Issouf , Nagot Nicolas , Foulongne Vincent , Ouedraogo Abdoulaye , Van de Perre Philippe , Mayaud Philippe , Segondy Michel ,   for the Yerelon Study Group
Published: April 2007

AbstractThe relationships between human papillomavirus type 16 (HPV 16) viral load, HPV 16 integration status, human immunodeficiency virus type 1 (HIV‐1) status, and cervical cytology were studied among women enrolled in a cohort of female sex workers in Burkina Faso. The study focused on 24 HPV 16‐infected women. The HPV 16 viral load in cervical samples was determined by real‐time PCR. Integration ratio was estimated as the ratio between E2 and E6 genes DNA copy numbers. Integrated HPV16 viral load was defined as the product of HPV 16 viral load by the integration ratio. High HPV 16 viral load and high integration ratio were more frequent among women with squamous intraepithelial lesions compared with women with normal cytology (33% vs. 11%, and 33% vs. 0%, respectively), and among women with high‐grade squamous intraepithelial lesions compared with women without high‐grade squamous intraepithelial lesions (50% vs. 17%, and 50% vs. 11%, respectively). High HPV 16 DNA load, but not high integration ratio, was also more frequent among HIV‐1‐positive women (39% vs. 9%; and 23% vs. 18%, respectively). The absence of statistical significance of these differences might be explained by the small study sample size. High‐integrated HPV 16 DNA load was significantly associated with the presence of high‐grade squamous intraepithelial lesions (50% vs. 5%, P = 0.03) in univariate and multivariate analysis (adjusted odds‐ratio: 19.05; 95% confidence interval (CI), 1.11–328.3, P = 0.03), but not with HIV‐1 or other high‐risk HPV types (HR‐HPV). Integrated HPV 16 DNA load may be considered as a useful marker of high‐grade cervical lesions in HPV 16‐infected women. J. Med. Virol. 79: 766–770, 2007. © 2007 Wiley‐Liss, Inc.
Genetic variability of the fusion protein and circulation patterns of genotypes of the respiratory syncytial virus
Authors: Kim Yun‐Kyung , Choi Eun‐Hwa , Lee Hoan‐Jong 
Published: April 2007

AbstractAlthough antigenic and genetic variations were shown to occur both in the G and F protein of respiratory syncytial virus (RSV), few studies looked at the variation of F gene. The F genotypes were determined by the evaluation of clustering patterns, via the phylogenetic analysis of the nucleotide sequences of a variable region in the F gene. One hundred seventy‐nine strains obtained from a children's hospital in Korea over nine consecutive epidemics were included. The relationship between the F and G genotypes was analyzed with the G genotypes previously published by the authors. The phylogenetic analysis of the variable region from the F gene revealed 9 genotypes among 129 group A RSVs and 4 genotypes among 50 group B RSVs. In each of the epidemics, the dominant genotypes were replaced with new genotypes in consecutive epidemics. In each of the epidemics of group B RSVs, the predominant genotype alternated between genotypes. Most of the strains which clustered to a particular F genotype were assigned to particular G genotype(s). By determining the nearly entire sequences of the F genes, we revealed the percentage of the nucleotide differences which resulted in amino acid coding changes was determined to be much great in two distinct variable regions of the F gene. Our results indicated that the F gene of the RSVs may be continuously evolving under selective pressure in a distinct pattern, and that the genetic variability of the F protein is associated with that of the G protein. J. Med. Virol. 79: 820–828, 2007. © 2007 Wiley‐Liss, Inc.
Increased susceptibility of human respiratory syncytial virus to neutralization by anti‐fusion protein antibodies on adaptation to replication in cell culture
Authors: Marsh R. , Connor A. , Gias E. , Toms G.L. 
Published: April 2007

AbstractSubgroup A respiratory syncytial viruses present in respiratory secretions and low passage level cell culture isolates were found to be markedly less susceptible to neutralization with monoclonal antibodies (MAbs) to the F glycoprotein than the cell culture adapted A2 virus strain. Low passage virus isolates collected over a 20 year period and belonging to several sub‐group A lineages were refractory to neutralization with antibodies recognizing two major neutralizing antigenic sites located sub‐terminally at opposite ends of the F1 glycoprotein sub‐unit. On further passage in cell culture, virus isolates exhibited both increased infectivity titers and increased susceptibility to neutralization by antibodies to both antigenic sites. The consensus nucleotide sequence of the membrane associated proteins M and of the SH, G and F glycoprotein genes, and their intergenic regions were compared for neutralization resistant and susceptible stocks of one virus strain, R17532. No changes were observed in the known monoclonal antibody epitopes on the F glycoprotein. In line with this, the increase in susceptibility was not found to be associated with any increased binding of monoclonal antibody to isolated F glycoprotein in a BIAcore™ assay, thus excluding the possibility that passage in cell culture selected for viruses with mutations in the antibody binding sites. M and SH genes were conserved but a number of sites in the G and F glycoprotein genes were found to vary on adaptation to cell culture suggesting that change in susceptibility to neutralization was associated with a change in the prevalent quasispecies present in the virus population. The genetic basis of phenotypic change in susceptibility remains to be determined. J. Med. Virol. 79: 829–837, 2007. © 2007 Wiley‐Liss, Inc.
Characterization of the rat urokinase plasminogen activator receptor promoter in PC12 cells
Authors: Su Feng , Kozak Katherine R. , Herschman Harvey , Reddy Srinivasa T. , Farias‐Eisner Robin 
Published: April 2007

AbstractRat PC12 pheochromocytoma cells treated with nerve growth factor (NGF) extend “neurites” and initiate a neuronal differentiation pathway. Although neurotrophins, growth factors [e.g., epidermal growth factor (EGF)], and other ligands induce many common primary response genes (PRGs) in PC12 cells, a unique PRG subset is induced preferentially by NGF. Expression of one NGF preferentially induced gene, urokinase plasminogen activator receptor (UPAR), is required for NGF‐induced neurite extension and neuronal differentiation. A 2.1‐kb fragment of the rat UPAR 5′ regulatory region confers differential expression by NGF versus EGF, following transfection of a luciferase reporter construct into PC12 cells. Deletion studies identified a region between −100 and −50 nucleotides from the transcription start site as the region conferring preferential NGF induction. Sequence comparisons among rat, human, and murine UPAR promoters identified two common potential regulatory regions. Site‐directed mutation identified an activator protein‐1 (AP‐1) region between −66 and −72 bp, required for luciferase reporter activation by NGF. Electrophoretic mobility shift and antibody supershift assays demonstrated that specific Fos and Jun family members preferentially bind to this site following NGF treatment. We conclude that preferential activation of transcription factor binding at this AP‐1 site mediates preferential NGF activation of the UPAR gene. © 2007 Wiley‐Liss, Inc.
c‐Jun phosphorylation in Alzheimer disease
Authors: Thakur Akanksha , Wang Xinglong , Siedlak Sandra L. , Perry George , Smith Mark A. , Zhu Xiongwei 
Published: April 2007

AbstractThe c‐Jun N‐terminal kinase (JNK) pathway is known to be activated by oxidative stress and can lead to either defensive‐protective adaptations in the cell or apoptosis. The JNK pathway is activated in Alzheimer disease (AD), as demonstrated in studies showing higher levels of phospho‐JNK in affected neurons in AD brains than in controls. c‐Jun, a transcription factor, is the downstream effector of JNK, whose activation requires phosphorylation of Ser63/Ser73. In this study, we characterized and compared the localization of c‐Jun phosphorylated at either Ser63 or Ser73 in the hippocampi of AD cases with that in age‐matched controls. Phospho‐c‐Jun (Ser73) was found to be strongly associated with neurofibrillary tangles and granulovacuolar degeneration (GVD) in addition to the nuclei in neurons in the hippocampal regions of the AD brain, but was virtually absent in most controls. Phospho‐c‐Jun (Ser63) was also found to be associated with GVD in AD brains. Indeed, phospho‐c‐Jun (Ser73) immunostaining was much more extensive than that of phospho‐c‐Jun (Ser63), with all the phospho‐c‐Jun (Ser63)–positive neurons also being phospho‐c‐Jun (Ser73) positive. Significant overlap between phospho‐c‐Jun and phospho‐JNK suggested a mechanistic link. In addition, the neurons showing increased levels of phospho‐c‐Jun (Ser73) in the cytoplasmic GVD were negative for TUNEL, suggesting a mechanism protecting the cells from death. Overall, this study demonstrated specific alterations in c‐Jun phosphorylation and distribution in AD which is not necessarily linked to apoptosis but rather may represent an adaptation process in the face of oxidative stress. © 2007 Wiley‐Liss, Inc.
Metabolic interactions between glutamatergic and dopaminergic neurotransmitter systems are mediated through D1 dopamine receptors
Authors: Rodrigues Tiago B. , Granado Noelia , Ortiz Oskar , Cerdán Sebastián , Moratalla Rosario 
Published: April 2007

AbstractInteractions between the dopaminergic and glutamatergic neurotransmission systems were investigated in the adult brain of wild‐type (WT) and transgenic mice lacking the dopamine D1 or D2 receptor subtypes. Activity of the glutamine cycle was evaluated by using 13C NMR spectroscopy, and striatal activity was assessed by c‐Fos expression and motor coordination. Brain extracts from (1,2‐13C2) acetate‐infused mice were prepared and analyzed by 13C NMR to determine the incorporation of the label into the C4 and C5 carbons of glutamate and glutamine. D1R−/− mice showed a significantly higher concentration of cerebral (4,5‐13C2) glutamine, consistent with an increased activity of the glutamate‐glutamine cycle and of glutamatergic neurotransmission. Conversely, D2R−/− mice did not show any significant changes in (4,5‐13C2) glutamate or (4,5‐13C2) glutamine, suggesting that alterations in glutamine metabolism are mediated through D1 receptors. This was confirmed with D1R−/− and WT mice treated with reserpine, a dopamine‐depleting drug, or with reserpine followed by L‐DOPA, a dopamine precursor. Exposure to reserpine increased (4,5‐13C2) glutamine in WT to levels similar to those found in untreated D1R−/− mice. These values were the same as those reached in the reserpine‐treated D1R−/− mice. Treatment of WT animals with L‐DOPA returned (4,5‐13C2) glutamine levels to normal, but this was not verified in D1R−/− animals. Reserpine impaired motor coordination and decreased c‐Fos expression, whereas L‐DOPA restored both variables to normal values in WT but not in D1R−/−. Together, our results reveal novel neurometabolic interactions between glutamatergic and dopaminergic systems that are mediated through the D1, but not the D2, dopamine receptor subtype. © 2007 Wiley‐Liss, Inc.