bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Resonance Imaging Findings in Patients Meeting Task Force Criteria for Arrhythmogenic Right Ventricular Dysplasia
Authors: Tandri Harikrishna , Calkins Hugh , Nasir Khurram , Bomma Chandra , Castillo Ernesto , Rutberg Julie , Tichnell Crystal , Lima João A.C. , Bluemke David A. 
Published: May 2003

Introduction: Magnet resonance imaging (MRI) findings in patients meeting Task Force criteria for the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD) have not been systematically described. We report qualitative and quantitative MRI findings in ARVD using state‐of‐the‐art MRI.
Methods and Results: MRI was performed on 12 patients with ARVD who were prospectively diagnosed using the Task Force criteria. The imaging protocol included breath‐hold double inversion recovery spin‐echo and gradient‐echo images. Ventricular volumes and dimensions were compared to 10 age‐ and sex‐matched normal volunteers. High intramyocardial T1 signal similar to fat signal was observed in 9 (75%) of the 12 patients and in none of the controls. Right ventricular (RV) hypertrophy was seen in 5 (42%) patients, trabecular disarray in 7 (59%), and wall thinning in 3 (25%). Both the RV end‐diastolic diameter and the outflow tract area were significantly higher in ARVD patients compared to controls (51.2 vs 43.2 mm,

P < 0.01

; and 14.5 vs

9.3 cm2, P < 0.01

, respectively). ARVD patients had a higher RV end‐diastolic volume index and lower RV ejection fraction compared with controls (127.4 vs

87.5, P < 0.01

; and 41.6% vs 57%,

P < 0.01

, respectively).
Conclusion: High intramyocardial T1 signal indicative of fat is seen in a high percentage (75%) of patients who meet the Task Force criteria for ARVD. Trabecular disarray is seen more frequently than wall thinning and aneurysms. RV dimensions and volumes differ significantly in ARVD compared to controls, indicating a role for quantitative evaluation in the diagnosis of ARVD.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 476‐482, May 2003)
Retracted: Impact of Classroom Dynamics on the Effectiveness of Recasts in Second Language Acquisition
Authors: Morris Frank A. , Tarone Elaine E. 
Published: May 2003

Forward Links to Citing Articles

Retraction. Language Learning 56: 1, p xii. Online publication date: 3‐Mar‐2006.Interpersonal conflict arose in the interactions of three dyads of learners engaged in collaborative work in a foreign language classroom. Results show that although learners corrected each other's errors using recasts, in several cases the learners continued to produce the erroneous form in posttests. Stimulated recall revealed that negative feelings about their conversation partners seemed to have caused some learners to interpret recasts not as helpful corrective feedback, but as criticism and even mockery. The social dynamics of the language classroom may in some cases dramatically alter the way the cognitive processes of attention, or noticing, are deployed in cooperative learning activities in which feedback occurs, and this in turn appears to affect acquisition.
Persistence of Extraordinarily Low Levels of Genetically Homogeneous Human Immunodeficiency Virus Type 1 in Exposed Seronegative Individuals
Authors: Zhu Tuofu , Corey Lawrence , Hwangbo Yon , Lee Jean M. , Learn Gerald H. , Mullins James I. , McElrath M. Juliana 
Published: May 2003

ABSTRACT

Some individuals remain inexplicably seronegative and lack evidence for human immunodeficiency virus type 1 (HIV-1) infection by conventional serologic or virologic testing despite repeated high-risk virus exposures. Here, we examined 10 exposed seronegative (ES) individuals exhibiting HIV-1-specific cytotoxicity for the presence of HIV-1. We discovered HIV-1 DNA in resting CD4
+
T cells (mean, 0.05 ± 0.01 copies per million cells) at multiple visits spanning 69 to 130 weeks in two ES individuals at levels that were on average 10
4
- to 10
6
-fold lower than those of other HIV-1-infected populations reported. Sequences of HIV-1 envelope and
gag
genes remained markedly homogeneous, indicating little to undetectable virus replication. These results provide the evidence for HIV-1 infection in ES individuals below the detection limit of standard assays, suggesting that extraordinary control of infection can occur. The two HIV-infected ES individuals remained healthy and were not superinfected with other HIV-1 strains despite continued high-risk sexual exposures to multiple HIV-infected partners. Understanding the mechanisms that confer diminished replicative capacity of HIV-1 in these hosts is paramount to developing strategies for protection against and control of HIV-1 infection.
Relationship between 3′-Azido-3′-Deoxythymidine Resistance and Primer Unblocking Activity in Foscarnet-Resistant Mutants of Human Immunodeficiency Virus Type 1 Reverse Transcriptase
Authors: Meyer Peter R. , Matsuura Suzanne E. , Zonarich Dianna , Chopra Rahul R. , Pendarvis Eric , Bazmi Holly Z. , Mellors John W. , Scott Walter A. 
Published: May 2003

ABSTRACTPhosphonoformate (foscarnet) is a pyrophosphate (PPi) analogue and a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT), acting through the PPibinding site on the enzyme. HIV-1 RT can unblock a chain-terminated DNA primer by phosphorolytic transfer of the terminal residue to an acceptor substrate (PPior a nucleotide such as ATP) which also interacts with the PPibinding site. Primer-unblocking activity is increased in mutants of HIV-1 that are resistant to the chain-terminating nucleoside inhibitor 3′-azido-3′-deoxythymidine (AZT). We have compared the primer-unblocking activity for HIV-1 RT containing various foscarnet resistance mutations (K65R, W88G, W88S, E89K, S117T, Q161L, M164I, and the double mutant Q161L/H208Y) alone or in combination with AZT resistance mutations. The level of primer-unblocking activity varied over a 150-fold range for these enzymes and was inversely correlated with foscarnet resistance and directly correlated with AZT resistance. Based on published crystal structures of HIV-1 RT, many of the foscarnet resistance mutations affect residues that do not make direct contact with the catalytic residues of RT, the incoming deoxynucleoside triphosphate (dNTP), or the primer-template. These mutations may confer foscarnet resistance and reduce primer unblocking by indirectly decreasing the binding and retention of foscarnet, PPi, and ATP. Alternatively, the binding position or orientation of PPi, ATP, or the primer-template may be changed in the mutant enzyme complex so that molecular interactions required for the unblocking reaction are impaired while dNTP binding and incorporation are not.
Boudicca
, a Retrovirus-Like Long Terminal Repeat Retrotransposon from the Genome of the Human Blood Fluke
Schistosoma mansoni
Authors: Copeland Claudia S. , Brindley Paul J. , Heyers Oliver , Michael Scott F. , Johnston David A. , Williams David L. , Ivens Alasdair C. , Kalinna Bernd H. 
Published: May 2003

ABSTRACT

The genome of
Schistosoma mansoni
contains a proviral form of a retrovirus-like long terminal repeat (LTR) retrotransposon, designated
Boudicca
. Sequence and structural characterization of the new mobile genetic element, which was found in bacterial artificial chromosomes prepared from
S. mansoni
genomic DNA, revealed the presence of three putative open reading frames (ORFs) bounded by direct LTRs of 328 bp in length. ORF1 encoded a retrovirus-like major homology region and a Cys/His box motif, also present in Gag polyproteins of related retrotransposons and retroviruses. ORF2 encoded enzymatic domains and motifs characteristic of a retrovirus-like polyprotein, including aspartic protease, reverse transcriptase, RNase H, and integrase, in that order, a domain order similar to that of the
gypsy
/
Ty3
retrotransposons. An additional ORF at the 3′ end of the retrotransposon may encode an envelope protein. Phylogenetic comparison based on the reverse transcriptase domain of ORF2 confirmed that
Boudicca
was a
gypsy
-like retrotransposon and showed that it was most closely related to
CsRn1
from the Oriental liver fluke
Clonorchis sinensis
and to
kabuki
from
Bombyx mori
. Bioinformatics approaches together with Southern hybridization analysis of genomic DNA of
S. mansoni
and the screening of a bacterial artificial chromosome library representing ≈8-fold coverage of the
S. mansoni
genome revealed that numerous copies of
Boudicca
were interspersed throughout the schistosome genome. By reverse transcription-PCR, mRNA transcripts were detected in the sporocyst, cercaria, and adult developmental stages of
S. mansoni
, indicating that
Boudicca
is actively transcribed in this trematode.
Gene Expression Profiling of the Cellular Transcriptional Network Regulated by Alpha/Beta Interferon and Its Partial Attenuation by the Hepatitis C Virus Nonstructural 5A Protein
Authors: Geiss Gary K. , Carter Victoria S. , He Yupeng , Kwieciszewski Bartlomiej K. , Holzman Ted , Korth Marcus J. , Lazaro Catherine A. , Fausto Nelson , Bumgarner Roger E. , Katze Michael G. 
Published: May 2003

ABSTRACTAlpha/beta interferons (IFN-α/β) induce potent antiviral and antiproliferative responses and are used to treat a wide range of human diseases, including chronic hepatitis C virus (HCV) infection. However, for reasons that remain poorly understood, many HCV isolates are resistant to IFN therapy. To better understand the nature of the cellular IFN response, we examined the effects of IFN treatment on global gene expression by using several types of human cells, including HeLa cells, liver cell lines, and primary fetal hepatocytes. In response to IFN, 50 of the approximately 4,600 genes examined were consistently induced in each of these cell types and another 60 were induced in a cell type-specific manner. A search for IFN-stimulated response elements (ISREs) in genomic DNA located upstream of IFN-stimulated genes revealed both previously identified and novel putative ISREs. To determine whether HCV can alter IFN-regulated gene expression, we performed microarray analyses on IFN-treated HeLa cells expressing the HCV nonstructural 5A (NS5A) protein and on IFN-treated Huh7 cells containing an HCV subgenomic replicon. NS5A partially blocked the IFN-mediated induction of 14 IFN-stimulated genes, an effect that may play a role in HCV resistance to IFN. This block may occur through repression of ISRE-mediated transcription, since NS5A also inhibited the IFN-mediated induction of a reporter gene driven from an ISRE-containing promoter. In contrast, the HCV replicon had very little effect on IFN-regulated gene expression. These differences highlight the importance of comparing results from multiple model systems when investigating complex phenomena such as the cellular response to IFN and viral mechanisms of IFN resistance.
Enhancement of Recombinant Adeno-Associated Virus Type 2-Mediated Transgene Expression in a Lung Epithelial Cell Line by Inhibition of the Epidermal Growth Factor Receptor
Authors: Smith Andrew D. , Collaco Roy F. , Trempe James P. 
Published: May 2003

ABSTRACTRecombinant adeno-associated viruses (rAAVs) have attracted considerable interest as gene delivery systems because they show long-term expression in vivo and transduce numerous cell types. Limitations to successful gene transduction from rAAVs have prompted investigations of a variety of treatments to enhance transgene expression from rAAV vectors. Tyrphostin-1, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, dramatically enhances rAAV transgene expression. Elegant studies have demonstrated that a single-strand D-sequence-binding protein (ssDBP) is phosphorylated by EGFR and binds to the D sequence element in the AAV terminal repeat (TR). Binding of the Tyr-phosphorylated ssDBP prevents conversion of single-stranded vector DNA to a double-strand conformation. We observed dramatic increases in transgene expression in lung epithelial cells (IB3) with tyrphostin treatment. Gel shift analysis of ssDBP revealed that its DNA binding characteristics were unchanged after tyrphostin treatment or adenovirus infection. Tyrphostin stimulated rAAV transgene expression to a greater extent than adenovirus coinfection. Southern hybridizations revealed that the vector DNA remained in the single-strand conformation in tyrphostin-treated cells but double-stranded replicative form monomer DNA was most abundant in adenovirus-infected cells. Northern analyses revealed that tyrphostin treatment enhanced mRNA accumulation more than in adenovirus-infected cultures even though replicative form DNA was undetectable. Analysis of the JNK, ERK, and p38K mitogen-activated protein kinase pathways revealed that tyrphostin treatment stimulated the activity of JNK and p38K. Our data suggest that tyrphostin-induced alteration of stress response pathways results in dramatic enhancement of transcription on linear vector DNA templates in the IB3 cell line. These results expand the downstream targets of the EGFR in regulating rAAV transduction.
Clearance of a Productive Lentivirus Infection in Calves Experimentally Inoculated with Caprine Arthritis-Encephalitis Virus
Authors: Morin Thierry , Guiguen François , Bouzar Baya Amel , Villet Stéphanie , Greenland Timothy , Grezel Délphine , Gounel Françoise , Gallay Kathy , Garnier Céline , Durand Jitka , Alogninouwa Théodore , Mselli-Lakhal Laïla , Mornex Jean-François , Chebloune Yahia 
Published: May 2003

ABSTRACTLentiviruses have long been considered host-specific pathogens, but several recent observations demonstrated their capacity to conquer new hosts from different species, genera, and families. From these cross-species infections emerged new animal and human infectious diseases. The successful colonization and adaptation of a lentivirus to a nonnatural host depends on unspecific and specific host barriers. Some of those barriers exert a relative control of viral replication (i.e., cytotoxic T-lymphocyte response, viral inhibitory factors), but none of them was found able to totally clear the infection once the retrovirus is fully adapted in its host. In this study we examined the evolution of the host-lentivirus interactions occurring in an experimental animal model of cross-species infection in order to analyze the efficiency of those barriers in preventing the establishment of a persistent infection. Five newborn calves were inoculated with caprine arthritis-encephalitis virus (CAEV), and the evolution of infection was studied for more than 12 months. All the animals seroconverted in the first 0.75 to 1 month following the inoculation and remained seropositive for the remaining time of the experiment. Viral infection was productive during 4 months with isolation of replication competent virus from the blood cells and organs of the early euthanized animals. After 4 months of infection, neither replication-competent virus nor virus genome could be detected in blood cells or in the classical target organs, even after an experimental immunosuppression. No evidence of in vitro restriction of CAEV replication was observed in cells from tissues explanted from organs of these calves. These data provide the demonstration of a natural clearance of lentivirus infection following experimental inoculation of a nonnatural host, enabling perspectives of development of new potential vaccine strategies to fight against lentivirus infections.
Activation of Adenovirus Early Promoters and Lytic Phase in Differentiated Strata of Organotypic Cultures of Human Keratinocytes
Authors: Noya Francisco , Balagué Cristina , Banerjee N. Sanjib , Curiel David T. , Broker Thomas R. , Chow Louise T. 
Published: May 2003

ABSTRACT
Human oncolytic adenoviruses have been used in clinical trials targeting cancers of epithelial origin. To gain a better understanding of the infectious cycle of adenovirus in normal human squamous tissues, we examined the viral infection process in organotypic cultures of primary human keratinocytes. We show that for the infection to occur, wounding of the epithelium is required. In addition, infection appears to initiate at the basal or parabasal cells that express the high-affinity coxsackievirus-adenovirus receptor, CAR, whereas the productive phase takes place in differentiated cells. This is due, at least in part, to the differentiation-dependent activation of the E1A and E2A early promoters and E4 promoters. We also show that adenovirus infection triggers a response mediated by the abnormal accumulation of cyclin E and p21cip1 proteins similar to the one previously observed in human papillomavirus-infected tissues. However, the virus seems to be able to overcome it, at least partially.
Excretion of Wild-Type and Vaccine-Derived Poliovirus in the Feces of Poliovirus Receptor-Transgenic Mice
Authors: Boot Hein J. , Kasteel Daniella T. J. , Buisman Anne-Marie , Kimman Tjeerd G. 
Published: May 2003

ABSTRACT
The emergence of circulating vaccine-derived poliovirus (cVDPV) strains in suboptimally vaccinated populations is a serious threat to the global poliovirus eradication. The genetic determinants for the transmissibility phenotype of polioviruses, and in particularly of cVDPV strains, are currently unknown. Here we describe the fecal excretion of wild-type poliovirus, oral polio vaccine, and cVDPV (Hispaniola) strains after intraperitoneal injection in poliovirus receptor-transgenic mice. Both the pattern and the level of fecal excretion of the cVDPV strains resemble those of wild-type poliovirus type 1. In contrast, very little poliovirus was present in the feces after oral polio vaccine administration. This mouse model will be helpful in elucidating the genetic determinants for the high fecal-oral transmission phenotype of cVDPV strains.
Viral Internal Ribosome Entry Site Structures Segregate into Two Distinct Morphologies
Authors: Beales Lucy P. , Holzenburg Andreas , Rowlands David J. 
Published: May 2003

ABSTRACT
An increasing number of viruses have been shown to initiate protein synthesis by a cap-independent mechanism involving internal ribosome entry sites (IRESs). Predictions of the folding patterns of these RNA motifs have been based primarily on sequence and biochemical analyses. Biophysical confirmation of the models has been achieved only for the IRES of hepatitis C virus (HCV), which adopts an open structure consisting of two major stems. We have conducted an extensive comparison of flavivirus and picornavirus IRES elements by negative stain transmission electron microscopy. All of the flavivirus IRESs we examined (those of GB virus-B, GB virus-C, and classical swine fever virus) fold to give a structure similar to that of the HCV IRES, as does an IRES recently found on mRNA encoded by human herpesvirus 8. The larger picornavirus IRESs (those of foot-and-mouth disease virus, rhinovirus, encephalomyocarditis virus, and hepatitis A virus) are morphologically similar, comprising a backbone with two protruding stems, and distinct from the flavivirus IRESs.
Incidence and Predicting Factors of Hypozincemia in Very-Low-Birth-Weight Infants at Near-Term Postmenstrual Age
Authors: Itabashi K. , Saito T. , Ogawa Y. , Uetani Y. 
Published: May 2003

We prospectively investigated serum zinc (Zn) concentrations and clinical factors in 118 very-low-birth-weight infants with a gestational age of 29.5 ± (SD) 2.5 weeks and a birth weight of 1,194 ± 254 g at near-term postmenstrual age. The 25th percentile of the serum Zn concentration was 7.0 µmol/l. The infants whose serum Zn concentrations were less than 7.0 µmol/l (defined as hypozincemia) did not have apparent symptoms of Zn deficiency. Multivariate logistic regression analyses demonstrated that hypozincemia was associated with factors such as weight gain (1-g/kg/day increase of weight; OR 1.1762, 95% CI 1.0414–1.3286) and serum albumin concentration (1-g/dl increase of serum albumin; OR 0.0816, 95% CI 0.0152–0.4372). The types of milk feeding did not affect the serum Zn concentrations in the study subjects. This study suggests that hypozincemia in very-low-birth-weight infants at near-term postmenstrual age is associated with greater weight gain and lower serum albumin concentration. Nutritional supply of Zn by human milk fortifier and preterm formula does not appear to meet the demands of rapidly growing very-low-birth-weight infants.
Enhancement of Antiradiation Potential of Some Aminothiols by Beta-Carotene
Authors: Al-Wandawi Hussain K. 
Published: May 2003

In the present study, protection of mice, BALB/c inbred as measured by survival at 30 days against whole-body gamma exposure at two dose levels, namely, 7.60 and 10.12 Gy by prior irradiation treatment with combination of β-carotene, N-(2-mercapto-propionyl)-glycine (MPG) and S-(2-aminoethyl) isothiouroniumbromide hydrobromide (AET), is reported. It was found that administration of β-carotene (1 mg per 20 g body mass) and 24 h before whole-body irradiation (7.60 Gy) had significantly improved the post-irradiation survival. It was also found that administration of a combination of AET (260 mg per kg body mass) and MPG (60 mg per kg body mass) 20 min before exposure to 7.60 Gy gamma irradiation to mice which have been treated with β-carotene (1 mg per 20 g body mass) 24 h before exposure had resulted in 80% survival in comparison to 10% survival recorded for control animals. On the other hand, when the animals were exposed to a higher dose (10.12 Gy) under similar experimental conditions as above, a significant improvement in survival was observed during the first 10 days following the exposure but only a slight effect afterward. On the other hand, the response of male and female mice 10 days after exposure to the above radiation dose indicated that the females were more radioresistant than the males.
Copper Supplementation Has No Effect on Markers of DNA Damage and Liver Function in Healthy Adults (FOODCUE Project)
Authors: O’Connor J.M. , Bonham M.P. , Turley E. , McKeown A. , McKelvey-Martin V.J. , Gilmore W.S. , Strain J.J. 
Published: May 2003

<i>Background/Aims:</i> Copper is routinely used in the laboratory to promote oxidation in vitro. However, copper concentrations are million-fold higher than physiological concentrations and, in contrast, accumulating evidence suggests that copper may have an antioxidant role in vivo. The aim of this study was to provide data on how increased intake of copper affected mononuclear leukocyte DNA damage and liver function in healthy young free-living men and women. <i>Methods:</i> The study design was a double-blind repeated crossover trial with treatment and intervening placebo periods, each of 6 weeks’ duration. The following supplementations were given orally in sequence: CuSO<sub>4</sub> at a dose of 3 mg copper/day and copper amino acid chelates at doses of 3 and 6 mg copper/day. Oxidative DNA damage was assessed using a modification of the alkaline Comet assay incorporating an endonuclease III digestion step. The assessment of liver function was by measurement of the liver enzymes, alanine aminotransferase and <i>L</i>-γ-glutamyltransferase. <i>Results:</i> There was no significant alteration in mononuclear leukocyte DNA damage or on liver function after 6 weeks of copper supplementation at two doses (3 and 6 mg/day). <i>Conclusions:</i> Copper supplementation (giving total copper intake at the highest level of 7 mg/day) did not induce DNA damage or adversely affect liver function in healthy adults.