bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computed tomography assessment of myocardial perfusion, viability, and function
Authors: Koyama Yasushi , Mochizuki Teruhito , Higaki Jitsuo 
Published: May 2004

AbstractIn addition to coronary artery assessment, contrast‐enhanced multidetector spiral computed tomography (CE‐MDCT) can provide valuable information about myocardial perfusion. Using CE‐MDCT, myocardial perfusion defects are often observed in the early phase of the contrast bolus (early defect (ED)), with residual defects (RDs) and late enhancement (LE) observed in the late phase in myocardial infarction (MI). However, the clinical significance of EDs, RDs, and LE has not yet been fully described. This work reviews myocardial viability and function by CE‐MDCT based on our prior data by including contrast‐enhanced single‐slice (detector) CT (CE‐SSCT) and CE‐MDCT. Recently, equivalent results were obtained, as seen in CE‐SSCT with images by CE‐MDCT. In this review, images that were acquired by MDCT will be presented. In this work, the following items will be the focus: myocardial enhancement patterns (EDs, LE, and RDs), early perfusion defects and their relationship to wall thickness (WT) and wall motion, early CT perfusion defects vs. Tl‐201 single photon emission CT (SPECT), the protocol for performing dual‐phase contrast CT, classification of enhancement patterns, enhancement patterns on dual‐phase CE‐MDCT vs. left ventricular functional recovery and WT, changes in enhancement patterns in conjunction with healing stage, enhancement patterns on dual‐phase CE‐MDCT vs. 201Tl/99mTc‐pyrophosphate (dual‐isotope SPECT), the clinical meaning of each enhancement pattern, pitfalls of enhancement patterns and other diseases, and study limitations and the future of MDCT. J. Magn. Reson. Imaging 2004;19:800–815. © 2004 Wiley‐Liss, Inc.
Radiation dose in multidetector row computed tomography cardiac imaging
Authors: Bae Kyongtae T. , Hong Cheng , Whiting Bruce R. 
Published: May 2004

AbstractMultidetector row computed tomography (MDCT) with its markedly improved temporal and spatial resolution has opened up a new opportunity in cardiac CT imaging. MDCT scanners are increasingly available and have become the preferred CT scanners for the entire spectrum of clinical CT examinations. As a consequence, the number of cardiac CT studies is continuously growing. Because cardiac CT studies involve considerable radiation doses, it is compelling for us to understand the radiation dose estimates associated with cardiac CT imaging. In this article, we review the concepts of radiation dose measurement in CT, discuss MDCT scan parameters affecting radiation exposure, and provide a reference summary of radiation dose estimates associated with MDCT cardiac imaging. J. Magn. Reson. Imaging 2004;19:859–863. © 2004 Wiley‐Liss, Inc.
Past, present, and future perspective of cardiac computed tomography
Authors: Becker Christoph R. , Knez Andreas 
Published: May 2004

AbstractIn the United States, more than 1 million diagnostic invasive coronary angiograms are performed annually, and in about 50% the investigation is followed by an interventional procedure. The remaining symptomatic patients after angiography are treated conservatively or by bypass graft surgery. In recent decades coronary angiography has advanced to a fast and safe investigation. Nevertheless, in particular, patients are well aware of the small but not negligible risk of complications and the discomfort of the invasive procedure. In addition to electrocardiogram (EKG) or ultrasound stress test and thallium scintigraphy, there is further need for another noninvasive method that displays the morphology of the coronary arteries in a way that would allow the triage of patients with suspicion of coronary artery disease (CAD) for a conservative, interventional, or surgical treatment. J. Magn. Reson. Imaging 2004;19:676–685. © 2004 Wiley‐Liss, Inc.
Induction of HIV‐specific antibody response and protection against vaginal SHIV transmission by intranasal immunization with inactivated SHIV‐capturing nanospheres in macaques
Authors: Miyake Ariko , Akagi Takami , Enose Yoshimi , Ueno Masamichi , Kawamura Masaki , Horiuchi Reii , Hiraishi Katsuya , Adachi Masakazu , Serizawa Takeshi , Narayan Opendra , Akashi Mitsuru , Baba Masanori , Hayami Masanori 
Published: May 2004

AbstractWe have previously reported that concanavalin A‐immobilized polystyrene nanospheres (Con A‐NS) could efficiently capture HIV‐1 particles and that intranasal immunization with inactivated HIV‐1‐capturing nanospheres (HIV‐NS) induced vaginal anti‐HIV‐1 IgA antibody response in mice. In this study, to evaluate the protective effect of immunization, each three macaques was intranasally immunized with Con A‐NS or inactivated simian/human immunodeficiency virus KU‐2‐capturing nanospheres (SHIV‐NS) and then intravaginally challenged with a pathogenic virus, SHIV KU‐2. After a series of six immunizations, vaginal anti‐HIV‐1 gp120 IgA and IgG antibodies were detected in all SHIV‐NS‐immunized macaques. After intravaginal challenge, one of the three macaques in each of the Con A‐NS‐ and SHIV‐NS‐immunized groups was infected. Plasma viral RNA load of infected macaque in SHIV‐NS‐immunized macaques was substantially less than that in unimmunized control macaque and reached below the detectable level. However, it could not be determined whether intranasal immunization with SHIV‐NS is effective in giving complete protection against intravaginal challenge. To explore the effect of the SHIV‐NS vaccine, the remaining non‐infected macaques were rechallenged intravenously with SHIV KU‐2. After intravenous challenge, all macaques became infected. However, SHIV‐NS‐immunized macaques had lower viral RNA loads and higher CD4+ T cell counts than unimmunized control macaques. Plasma anti‐HIV‐1 gp120 IgA and IgG antibodies were induced more rapidly in the SHIV‐NS‐immunized macaques than in the controls. The rapid antibody responses having neutralizing activity might contribute to the clearance of the challenge virus. Thus, SHIV‐NS‐immunized macaques exhibited partial protection to vaginal and systemic challenges with SHIV KU‐2. J. Med. Virol. 73:368–377, 2004. © 2004 Wiley‐Liss, Inc.
High rate of spontaneous clearance of acute hepatitis C virus genotype 3 infection
Authors: Lehmann Marc , Meyer Manuela F. , Monazahian Masyar , Tillmann Hans L. , Manns Michael P. , Wedemeyer Heiner 
Published: May 2004

AbstractTreating acute hepatitis C with interferon alpha prevents chronicity in nearly all cases when therapy is initiated within 3 months after infection. However, 15–50% of untreated patients may clear the hepatitis C virus (HCV) spontaneously. Therefore, factors are needed to identify patients prior to therapy who have a higher or lower risk for developing a chronic course to avoid unnecessary treatment. The role of the HCV genotype for spontaneous recovery from acute hepatitis C has been discussed controversially. In the year 2002, all 1,176 new incoming prisoners in a Northern German prison for young men (age 16–24) were screened for anti‐HCV antibodies and 92 tested positive. Ninety eight percent of these reported i.v.‐drug abuse for a median of 32 months prior to imprisonment. HCV‐RNA negative individuals (21%) were serotyped and HCV‐RNA positive patients were genotyped. The prevalence of HCV genotype 3 was significantly higher among individuals who had cleared HCV spontaneously as compared to chronically infected patients (86% vs. 38%; P = 0.002). Ninety three percent of individuals exposed to HCV genotype 1 but only 63% of individuals exposed to genotype 3 experienced a chronic course of the infection (P = 0.006). Thus, acute infection in young Caucasian men with HCV genotype 3 leads more often to spontaneous clearance than infection with HCV genotype‐1. Considering also the high chance of successful treatment of chronic HCV genotype 3 infection with pegylated‐interferon in combination with ribavirin, we suggest not to treat acute hepatitis C genotype 3 infection early but rather to wait at least 3 months after the onset of symptoms when chronicity becomes likely. J. Med. Virol. 73:387–391, 2004. © 2004 Wiley‐Liss, Inc.
The predictive value of core antigen testing for the management of hepatitis C patients receiving pegylated interferon/ribavirin treatment
Authors: Pradat Pierre , Maynard Marianne , Buti Maria , Berthillon Pascale , Picchio Gaston , Tillmann Hans L. , Wiegand Johannes , Voirin Nicolas , Manns Michael P. , Esteban Juan‐Ignacio , Martinot Michèle , Marcellin Patrick , Trepo Christian 
Published: May 2004

AbstractA new quantitative marker of HCV viremia based on the detection of the core antigen of the virus has recently become commercially available in Europe. The usefulness of this test was examined for the management of patients treated with pegylated interferon/ribavirin. One hundred twenty‐eight pegylated interferon/ribavirin treated patients were studied. Serum samples were available at baseline, week 4 and week 12 time‐points, respectively. Core antigen was quantified using the trak‐C assay (Ortho Clinical Diagnostics, Raritan, NJ). For all genotypes at week 4, the positive and negative predictive values of HCV core antigen were 81.4 and 92.9%, respectively, while at week 12 they were 67.9 and 100%, respectively. These predictive values varied substantially according to viral genotype. Among patients with a negative core antigen level (<1.5 pg/ml) at week 12, only 33% of those who were positive at week 4 achieved a sustained virological response whereas 85% of those who were already negative did (P < 0.001). The core antigen assay may be used at week 4 and week 12 to distinguish patients who will achieve a sustained virological response from those who will relapse/breakthrough. This assay is a new reliable alternative for early prediction of virological non‐response in patients treated with pegylated interferon/ribavirin. J. Med. Virol. 73:392–396, 2004. © 2004 Wiley‐Liss, Inc.
Clinically‐based determination of safe DNAemia cutoff levels for preemptive therapy or human cytomegalovirus infections in solid organ and hematopoietic stem cell transplant recipients
Authors: Lilleri Daniele , Baldanti Fausto , Gatti Marta , Rovida Francesca , Dossena Luca , Grazia Simona De , Torsellini Maria , Gerna Giuseppe 
Published: May 2004

AbstractTransplantation Centers using human cytomegalovirus (HCMV) antigenemia‐based preemptive therapy will need to replace in the near future the antigenemia assay with a more standardized and automatable assay, such as a molecular assay quantifying HCMV DNA in blood (DNAemia). Thus, in view of replacing antigenemia with clinically safe cutoff values, DNAemia levels corresponding to antigenemia cutoffs guiding HCMV preemptive therapy were determined retrospectively in solid organ and hematopoietic stem cell transplant recipients (HSCTR) using an “in‐house” quantitative PCR (QPCR) method. Since preemptive therapy had prevented appearance of HCMV disease in all patients tested, DNA cutoffs determined retrospectively had to be considered as safe clinically as antigenemia cutoffs used prospectively. However, in solid organ transplant recipients (SOTR), initiating preemptive therapy upon an antigenemia cutoff of 100 pp65‐positive leukocytes, a DNAemia cutoff of 300,000 copies/ml blood had positive and negative predictive values of >90%, indicating that a DNAemia cutoff could achieve, in terms of prevention of HCMV disease, the same clinical results as the antigenemia cutoff. In HSCTR, initiating preemptive therapy upon first antigenemia positivity, a DNAemia cutoff of 10,000 copies/ml blood had a positive predictive value of >90%, indicating that the great majority of patients treated under the antigenemia guidance would have been treated also using this DNA cutoff. On the other hand, the negative predictive value of 28.6% indicated that two out of three HSCTR had been treated under the antigenemia guidance having the same levels of viral DNA as the untreated patients. The data suggest that a quantitative cutoff could be adopted as a guiding criterion for preemptive therapy also in HSCTR. Regression analysis allowed to determine the DNAemia (corresponding to QPCR) cutoff values for two commercial assays tested both in solid organ and HSCTR. Retrospective DNAemia cutoff values will be verified for safety in prospective trials. J. Med. Virol. 73:412–418, 2004. © 2004 Wiley‐Liss, Inc.
Enterovirus infections with β‐cell tropic strains are frequent in siblings of children diagnosed with type 1 diabetes children and in association with elevated levels of GAD65 antibodies
Authors: Frisk Gun , Tuvemo Torsten 
Published: May 2004

AbstractEnterovirus infections have been associated with type 1 diabetes in a number of reports. Recent prospective studies have suggested that enterovirus infections initiate the autoimmune process. Variation in virulence and replication pattern between strains of a serotype has also been shown. The aim was to study if there were specific Coxsackievirus strains that were associated more often with the type 1 diabetes children than with controls and/or siblings and to analyse if there was any time‐relationship between such infections and the appearance of antibodies against glutamic acid decarboxylase 65 (GAD65). In the present study, serum was tested from newly diagnosed type 1 diabetes children, their siblings and matched controls for neutralising antibodies against different strains of Coxsackievirus B (CBV). Tests for the presence of antibodies against GAD65 in the same groups were also carried out. Newly diagnosed type 1 diabetes children revealed higher titres of neutralising antibodies against a strain of Coxsackievirus B4 (CBV‐4, VD2921) that has been shown to cause persistent infection in human pancreatic islet cells. The type 1 diabetes child and its sibling often encountered the same infection. Among the former, 16 of 27 (59%) had a significant rise in neutralising antibodies. Eight of the type 1 diabetes children had such a rise against a recombinant strain, V89 4557. Among the siblings 10 of 13 (77%) had significant titre increases. Among the type 1 diabetes children, increasing neutralising titres was associated positively with increasing antibody levels against GAD65. All siblings with antibodies against GAD 65 had significant titre increase against any of the CBV strains. J. Med. Virol. 73:450–459, 2004. © 2004 Wiley‐Liss, Inc.
Positively charged synthetic peptides from structural proteins of papillomaviruses abrogate human papillomavirus infectivity
Authors: Bousarghin Latifa , Touzé Antoine , Yvonnet Bernard , Coursaget Pierre 
Published: May 2004

AbstractHuman papillomavirus (HPV) virus‐like particles (VLP) and synthetic peptides corresponding to positively‐charged sequences of the major and minor capsid proteins were tested for their efficacy in inhibiting the infectivity of HPV 31 pseudovirions by blocking virus entry into cells. A greater than 80% reduction of transfection was observed with one HPV‐31 peptide at a concentration of 10 μg/ml. Moreover, the blocking was not type‐specific since similar reduction in transfection was observed with peptides from other HPV types at a concentration of 60 μg/ml. This concentration was non‐toxic for the cells. These findings indicate that some of the positively‐charged sequences of the L1 and L2 HPV capsid proteins of papillomavirus are compounds that might be locally active against sexually transmitted papillomavirus. The findings provide further evidence that cellular glycosamino‐glycans (GAGs) are functional receptors for HPVs. J. Med. Virol. 73:474–480, 2004. © 2004 Wiley‐Liss, Inc.
Differential effects of polycyclic aromatic hydrocarbons on transactivation of AP‐1 and NF‐κB in mouse epidermal cl41 cells
Authors: Li Jingxia , Chen Haobin , Ke Qingdong , Feng Zhaohui , Tang Moon‐Shong , Liu Bingci , Amin Shantu , Costa Max , Huang Chuanshu 
Published: May 2004

AbstractPolycyclic aromatic hydrocarbons (PAHs) and their derivatives, such as benzo[a]pyrene (B[a]P), (±)‐anti‐benzo[a]pyrene‐7,8‐diol‐9,10‐epoxide (B[a]PDE), and 5‐methylchrysene‐1,2‐diol‐3,4‐epoxide (5‐MCDE), are complete carcinogens. However, the tumor promotion effects of PAHs remain unclear. We therefore investigated the possible activation of activator protein‐1 (AP‐1) and nuclear factor‐κB (NFκB) in mouse epidermal Cl41 cells after different PAHs treatments, including B[a]P, B[a]PDE, chrysene‐1,2‐diol‐3,4‐epoxid (CDE), and 5‐MCDE. The results showed that B[a]PDE and 5‐MCDE were able to activate AP‐1 and NF‐κB, whereas B[a]P showed only marginal effect on AP‐1 activation, and B[a]P and CDE had no effect on NF‐κB activation. Treatment with either B[a]PDE or 5‐MCDE also resulted in mitogen‐activated protein kinases (MAPKs) activation as well as inhibitory subunit kappa‐B (IκBα) phosphorylation and degradation, whereas B[a]P and CDE had no effect. Pretreatment with PD98059, a specific inhibitor for extracellular signal‐regulated protein kinases (ERKs) upstream kinase MEK1/2, or SB202190, a p38 kinase inhibitor, resulted in a dramatic inhibition of B[a]PDE‐induced AP‐1 transactivation. In addition, B[a]PDE‐induced AP‐1 activation was also inhibited by overexpressing a dominant negative mutant of JNK1 in the cells. All these suggest ERKs, c‐jun N‐terminal kinases (JNKs), and p38 kinase signal transduction pathways are required for AP‐1 induction by B[a]PDE. Taken together, B[a]PDE and 5‐MCDE are the active compounds of PAHs to initiate signaling pathways. Considering the important roles of AP‐1 and NF‐κB in tumor promotion, we speculated the activation of AP‐1 and NF‐κB by B[a]PDE and 5‐MCDE may involve in their or their parent compounds' tumor promotion effects. This study may help in better understanding the tumor promotion effects of PAHs. © 2004 Wiley‐Liss, Inc.
Electronic influences on 3J(C,H) coupling constants via S, S(O) and SO2: their determination, calculation and comparison of detection methods
Authors: Heydenreich Matthias , Koch Andreas , Kovács József , Tóth Gábor , Kleinpeter Erich 
Published: May 2004

Abstract3J(C,H) coupling constants via a sulfur atom in two series of compounds, both including a sulfide, a sulfoxide and a sulfone, were detected experimentally and calculated by quantum mechanical methods. In the first series (1–3) the coupling between a hydrogen, bonded to an sp3 carbon, and an sp2 carbon is treated; the second series (4–6) deals with the coupling between a hydrogen, bonded to an sp3 carbon, and an sp3 carbon. Different pulse sequences (broadband HMBC, SelJres, 1D HSQMBC, J‐HMBC‐2, selective J‐resolved long‐range experiment and IMPEACH‐MBC) proved to be useful in determining the long‐range 3J(C,H) coupling constants. However, the dynamic behaviour of two of the compounds (4 and 6) led to weighted averages of the two coupling constants expected (concerning equatorial and axial positions of the corresponding hydrogens). DFT calculations proved to be useful to calculate not only the 3J(C,H) coupling constants but also the different contributions of FC, PSO, DSO and SD terms; the calculation of the Fermi contact term (FC) was found to be sufficient for the correct estimation of 3J(C,H) coupling constants. Copyright © 2004 John Wiley & Sons, Ltd.
Radiofrequency power deposition utilizing thermal imaging
Authors: Cline Harvey , Mallozzi Richard , Li Zhu , McKinnon Graeme , Barber William 
Published: May 2004

AbstractWavelength effects influence radiofrequency (RF) power deposition distributions and limit magnetic resonance (MR) medical applications at very high magnetic fields. The power depositions in spherical saline gel phantoms were deduced from proton resonance shift thermal maps at both 1.5 T and 3.0 T over a range of conductivities. Phase differences before and after RF heating were measured for both a quadrature head coil and a circular surface coil. A long echo time (TE) pulse sequence with a 3D phase unwrap algorithm provided increased thermal sensitivity. The measured thermal maps agreed with a model of eddy‐current heating by circularly polarized oscillating RF fields in a conducting dielectric sphere. At 3.0 T, thermal maps were acquired with a <0.32°C temperature rise at 4 W. Proton resonance shift thermal maps provided a measure of hot spots in very‐high‐field MR imaging (MRI), in which both the phase sensitivity and signal‐to‐noise ratio (SNR) were increased. The method provides a means of studying the heat distribution generated by RF coils excited by clinical pulse sequences. Magn Reson Med 51:1129–1137, 2004. © 2004 Wiley‐Liss, Inc.
Lactate isotopomer analysis by 1H NMR spectroscopy: Consideration of long‐range nuclear spin–spin interactions
Authors: Lloyd Steven G. , Zeng Huadong , Wang PeiPei , Chatham John C. 
Published: May 2004

AbstractLactate is a key metabolite and its rates of cellular uptake and release, its production rates from glucose and glycogen, and its interconversion rate with pyruvate are important determinants of cellular energy production. If lactate precursors such as pyruvate and glucose are labeled appropriately with 13C, 1H NMR spectroscopy provides a means of quantifying lactate production from each source and allows measurement of all these rates within a single experiment. However, due to the multiplicities of the resonance lines (from nuclear spin–spin couplings) in lactate 13C isotopomers, the 1H NMR spectra were found to be more complex than expected, requiring determination of all spin–spin interactions in this anion. All such values were determined for lactate and its precursor pyruvate. The method was then applied to simultaneously measure the rates of exogenous lactate uptake and rates of release of glucose‐, glycogen‐, and pyruvate‐derived lactate in the isolated perfused rat heart. Magn Reson Med 51:1279–1282, 2004. © 2004 Wiley‐Liss, Inc.
Fast frequency mapping with balanced SSFP: Theory and application to proton‐resonance frequency shift thermometry
Authors: Scheffler Klaus 
Published: May 2004

AbstractA method is presented for the rapid acquisition of frequency maps based on multiecho balanced steady‐state free precession (balanced SSFP, fast imaging with steady precession (True FISP), fast imaging employing steady‐state excitation (FIESTA), or balanced fast field echo (FFE)). This technique was applied to measure temperature changes within a gel phantom based on the temperature‐sensitive water proton‐resonance frequency. The frequency was determined as the slope of a linear fit of the phases measured at different TEs along the echo train. The signal‐to‐noise ratio (SNR) of multiecho SSFP was analyzed for different parameters, such as relaxation times and flip angle, as well as for different local field inhomogeneities. The theoretical and experimental results were compared with results from the established multiecho fast low‐angle shot (FLASH) method. Depending on the given tissue parameters, a significant increase in the accuracy of the frequency/temperature shift estimation compared to FLASH was observed. Furthermore, balanced SSFP can be used with very short TRs without generating a saturation‐related signal loss, which is essential for real‐time temperature mapping. Magn Reson Med 51:1205–1211, 2004. © 2004 Wiley‐Liss, Inc.