bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Simian Immunodeficiency Virus 5′ Untranslated Leader Sequence Plays a Role in Intracellular Viral Protein Accumulation and in RNA Packaging
Authors: Patel Jignesh , Wang Shainn-Wei , Izmailova Elena , Aldovini Anna 
Published: May 2003

ABSTRACT

We investigated the role of 5′ untranslated leader sequences of simian immunodeficiency virus (SIV
mac239
) in RNA encapsidation and protein expression. A series of progressively longer deletion mutants was constructed with a common endpoint six nucleotides upstream of the
gag
initiation codon and another endpoint at the 3′ end of the primer binding site (PBS). We found that efficient intracellular Gag-Pol protein accumulation required the region between the PBS and splice donor (SD) site. Marked reduction of genomic RNA packaging was observed with all the deletion mutants that involved sequences at both the 5′ and at the 3′ ends of the major SD site, and increased nonspecific RNA incorporation could be detected in these mutants. RNA encapsidation was affected only modestly by a deletion of 54 nucleotides at the 3′ end of the SD site when the mutant construct pΔ54 was transfected alone. In contrast, the amount of pΔ54 genomic RNA incorporated into particles was reduced more than 10-fold when this mutant was cotransfected with a construct specifying an RNA molecule with a wild-type packaging signal. Therefore, we conclude that the 175 nucleotides located 5′ of the
gag
initiation codon are critical for efficient and selective incorporation of genomic RNA into virions. This location of the SIV Ψ element provides the means for efficient discrimination between viral genomic and spliced RNAs.
Infection with Theiler's Murine Encephalomyelitis Virus Directly Induces Proinflammatory Cytokines in Primary Astrocytes via NF-κB Activation: Potential Role for the Initiation of Demyelinating Disease
Authors: Palma JoAnn P. , Kwon Daeho , Clipstone Neil A. , Kim Byung S. 
Published: May 2003

ABSTRACTTheiler's virus infection in the central nervous system (CNS) induces a demyelinating disease very similar to human multiple sclerosis. We have assessed cytokine gene activation upon Theiler's murine encephalomyelitis virus (TMEV) infection and potential mechanisms in order to delineate the early events in viral infection that lead to immune-mediated demyelinating disease. Infection of SJL/J primary astrocyte cultures induces selective proinflammatory cytokine genes (interleukin-12p40 [IL-12p40], IL-1, IL-6, tumor necrosis factor alpha, and beta interferon [IFN-β]) important in the innate immune response to infection. We find that TMEV-induced cytokine gene expression is mediated by the NF-κB pathway based on the early nuclear NF-κB translocation and suppression of cytokine activation in the presence of specific inhibitors of the NF-κB pathway. Further studies show this to be partly independent of dsRNA-dependent protein kinase (PKR) and IFN-α/β pathways. Altogether, these results demonstrate that infection of astrocytes and other CNS-resident cells by TMEV provides the early NF-κB-mediated signals that directly activate various proinflammatory cytokine genes involved in the initiation and amplification of inflammatory responses in the CNS known to be critical for the development of immune-mediated demyelination.
Structure of Intracellular Mature Vaccinia Virus Visualized by In Situ Atomic Force Microscopy
Authors: Malkin A. J. , McPherson A. , Gershon P. D. 
Published: May 2003

ABSTRACT
Vaccinia virus, the basis of the smallpox vaccine, is one of the largest viruses to replicate in humans. We have used in situ atomic force microscopy (AFM) to directly visualize fully hydrated, intact intracellular mature vaccinia virus (IMV) virions and chemical and enzymatic treatment products thereof. The latter included virion cores, core-enveloping coats, and core substructures. The isolated coats appeared to be composed of a highly cross-linked protein array. AFM imaging of core substructures indicated association of the linear viral DNA genome with a segmented protein sheath forming an extended ∼16-nm-diameter filament with helical surface topography; enclosure of this filament within a 30- to 40-nm-diameter tubule which also shows helical topography; and enclosure of the folded, condensed 30- to 40-nm-diameter tubule within the core by a wall covered with peg-like projections. Proteins observed attached to the 30- to 40-nm-diameter tubules may mediate folding and/or compaction of the tubules and/or represent vestiges of the core wall and/or pegs. An accessory “satellite domain” was observed protruding from the intact core. This corresponded in size to isolated 70- to 100-nm-diameter particles that were imaged independently and might represent detached accessory domains. AFM imaging of intact virions indicated that IMV underwent a reversible shrinkage upon dehydration (as much as 2.2- to 2.5-fold in the height dimension), accompanied by topological and topographical changes, including protrusion of the satellite domain. As shown here, the chemical and enzymatic dissection of large, asymmetrical virus particles in combination with in situ AFM provides an informative complement to other structure determination techniques.
A New Sendai Virus Vector Deficient in the Matrix Gene Does Not Form Virus Particles and Shows Extensive Cell-to-Cell Spreading
Authors: Inoue Makoto , Tokusumi Yumiko , Ban Hiroshi , Kanaya Takumi , Shirakura Masayuki , Tokusumi Tsuyoshi , Hirata Takahiro , Nagai Yoshiyuki , Iida Akihiro , Hasegawa Mamoru 
Published: May 2003

ABSTRACT

A new recombinant Sendai virus vector (SeV/ΔM), in which the gene encoding matrix (M) protein was deleted, was recovered from cDNA and propagated in a packaging cell line expressing M protein by using a Cre/
loxP
induction system. The titer of SeV/ΔM carrying the enhanced green fluorescent protein gene in place of the M gene was 7 × 10
7
cell infectious units/ml or more. The new vector showed high levels of infectivity and gene expression, similar to those of wild-type SeV vector, in vitro and in vivo. Virus maturation into a particle was almost completely abolished in cells infected with SeV/ΔM. Instead, SeV/ΔM infection brought about a significant increase of syncytium formation under conditions in which the fusion protein was proteolytically cleaved and activated by trypsin-like protease. This shows that SeV/ΔM spreads markedly to neighboring cells in a cell-to-cell manner, because both hemagglutinin-neuraminidase and active fusion proteins are present at very high levels on the surface of cells infected with SeV/ΔM. Thus, SeV/ΔM is a novel type of vector with the characteristic features of loss of virus particle formation and gain of cell-to-cell spreading via a mechanism dependent on the activation of the fusion protein.
Host Range of Kaposi's Sarcoma-Associated Herpesvirus in Cultured Cells
Authors: Bechtel Jill T. , Liang Yuying , Hvidding Joshua , Ganem Don 
Published: May 2003

ABSTRACT
Difficulties in efficiently propagating Kaposi's sarcoma-associated herpesvirus (KSHV) in culture have generated the impression that the virus displays a narrow host range. Here we show that, contrary to expectation, KSHV can establish latent infection in many adherent cell lines, including human and nonhuman cells of epithelial, endothelial, and mesenchymal origin. (Paradoxically, the only lines in which we have not observed successful latent infection are cultured lymphoma cell lines.) In most latently infected lines, spontaneous lytic replication is rare and (with only two exceptions) is not efficiently induced by phorbol ester treatment—a result that explains the failure of most earlier studies to observe efficient serial transfer of infection. However, ectopic expression of the KSHV lytic switch protein RTA from an adenoviral vector leads to the prompt induction of lytic replication in all latently infected lines, with the production of infectious KSHV virions. These results indicate (i) that the host cell receptor(s) and entry machinery for KSHV are widely distributed on cultured adherent cells, (ii) that latency is the default pathway of infection, and (iii) that blocks to lytic induction are frequent and largely reside at or upstream of the expression of KSHV RTA.
Defects in Human Immunodeficiency Virus Budding and Endosomal Sorting Induced by TSG101 Overexpression
Authors: Goila-Gaur Ritu , Demirov Dimiter G. , Orenstein Jan M. , Ono Akira , Freed Eric O. 
Published: May 2003

ABSTRACT
Retrovirus budding is greatly stimulated by the presence of Gag sequences known as late or L domains. The L domain of human immunodeficiency virus type 1 (HIV-1) maps to a highly conserved Pro-Thr-Ala-Pro (PTAP) sequence in the p6 domain of Gag. We and others recently observed that the p6 PTAP motif interacts with the cellular endosomal sorting protein TSG101. Consistent with a role for TSG101 in virus release, we demonstrated that overexpressing the N-terminal, Gag-binding domain of TSG101 (TSG-5′) suppresses HIV-1 budding by blocking L domain function. To elucidate the role of TSG101 in HIV-1 budding, we evaluated the significance of the binding between Gag and TSG-5′ on the inhibition of HIV-1 release. We observed that a mutation in TSG-5′ that disrupts the Gag/TSG101 interaction suppresses the ability of TSG-5′ to inhibit HIV-1 release. We also determined the effect of overexpressing a panel of truncated TSG101 derivatives and full-length TSG101 (TSG-F) on virus budding. Overexpressing TSG-F inhibits HIV-1 budding; however, the effect of TSG-F on virus release does not require Gag binding. Furthermore, overexpression of the C-terminal portion of TSG101 (TSG-3′) potently inhibits budding of not only HIV-1 but also murine leukemia virus. Confocal microscopy data indicate that TSG-F and TSG-3′ overexpression induces an aberrant endosome phenotype; this defect is dependent upon the C-terminal, Vps-28-binding domain of TSG101. We propose that TSG-5′ suppresses HIV-1 release by binding PTAP and blocking HIV-1 L domain function, whereas overexpressing TSG-F or TSG-3′ globally inhibits virus release by disrupting the cellular endosomal sorting machinery. These results highlight the importance of TSG101 and the endosomal sorting pathway in virus budding and suggest that inhibitors can be developed that, like TSG-5′, target HIV-1 without disrupting endosomal sorting.
Identification of Herpes Simplex Virus Type 1 Latency-Associated Transcript Sequences That both Inhibit Apoptosis and Enhance the Spontaneous Reactivation Phenotype
Authors: Jin Ling , Peng Weiping , Perng Guey-Chuen , Brick David J. , Nesburn Anthony B. , Jones Clinton , Wechsler Steven L. 
Published: May 2003

ABSTRACT
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for the high spontaneous and induced reactivation phenotype of HSV-1 in the rabbit ocular model and for the high induced reactivation phenotype in the mouse ocular model. Recently we showed that LAT has an antiapoptosis function, and we hypothesized that LAT's ability to inhibit apoptosis played an important role in LAT's ability to enhance the reactivation phenotype. Expression of just the first 1.5 kb of the 8.3-kb LAT gene is sufficient for both inhibition of apoptosis in an in vitro transient-transfection assay and the high spontaneous reactivation phenotype in vivo. Here we show the results of more complex mapping studies in which inhibition of apoptosis and the enhanced spontaneous reactivation phenotype also appear to be linked. The HSV-1 mutant virus dLAT371 has a high spontaneous reactivation phenotype in rabbits, suggesting that the LAT region deleted in this mutant (LAT nucleotides 76 to 447) is not required for this phenotype. The LAT3.3A viral mutant (which expresses LAT nucleotides 1 to 1499) also has a high spontaneous reactivation phenotype, suggesting that the region of LAT not expressed by this mutant (LAT nucleotide 1500 to the end of LAT) is also not required for this phenotype. Surprisingly, LAT2.9A, which is a combination of dLAT371 and LAT3.3A (i.e., it expresses LAT nucleotides 1 to 76 and 447 to 1499), has a low spontaneous reactivation phenotype indistinguishable from that of LAT null mutants. We report here that consistent with the low spontaneous reactivation phenotype of LAT2.9A, a plasmid expressing the identical LAT RNA did not inhibit caspase 9-induced apoptosis. In contrast, plasmids containing the same deletion but able to transcribe up to or past LAT nucleotide 2850 (rather than just up to LAT nucleotide 1499) inhibited caspase 9-induced apoptosis, consistent with the high spontaneous reactivation phenotype of dLAT371. Thus, LAT2.9A may have a low spontaneous reactivation phenotype because the LAT RNA that is made cannot block apoptosis, and dLAT371 apparently has a high spontaneous reactivation phenotype because the LAT RNA made has significant antiapoptosis activity. Furthermore, LAT appeared to have at least two regions capable of interfering with caspase 9-induced apoptosis. One region partially overlaps LAT nucleotides 76 to 447. The second region is partially (or completely) downstream of LAT nucleotide 1499.
The Herpes Simplex Virus 1 U
S
3 Protein Kinase Blocks Caspase-Dependent Double Cleavage and Activation of the Proapoptotic Protein BAD
Authors: Benetti Luca , Munger Joshua , Roizman Bernard 
Published: May 2003

ABSTRACT

An earlier report showed that the U
S
3 protein kinase blocked the apoptosis induced by the herpes simplex virus 1 (HSV-1)
d
120 mutant at a premitochondrial stage. Further studies revealed that the kinase also blocks programmed cell death induced by the proapoptotic protein BAD. Here we report the effects of the U
S
3 protein kinase on the function and state of a murine BAD protein. Specifically, (i) in uninfected cells, BAD was processed by at least two proteolytic cleavages that were blocked by a general caspase inhibitor. The untreated transduced cells expressed elevated caspase 3 activity. (ii) In cells cotransduced with the U
S
3 protein kinase, the BAD protein was not cleaved and the caspase 3 activity was not elevated. (iii) Inasmuch as the U
S
3 protein kinase blocked the proapoptotic activity and cleavage of a mutant (BAD3S/A) in which the codons for the regulatory serines at positions 112, 136, and 155 were each replaced with alanine codons, the U
S
3 protein kinase does not act by phosphorylation of these sites nor was the phosphorylation of these sites required for the antiapoptotic function of the U
S
3 protein kinase. (iv) The U
S
3 protein kinase did not enable the binding of the BAD3S/A mutant to the antiapoptotic proteins 14-3-3. Finally, (v) whereas cleavage of BAD at ASP56 and ASP61 has been reported and results in the generation of a more effective proapoptotic protein with an
M
r
of 15,000, in this report we also show the existence of a second caspase-dependent cleavage site most likely at the ASP156 that is predicted to inactivate the proapoptotic activity of BAD. We conclude that the primary effect of U
S
3 was to block the caspases that cleave BAD at either residue 56 or 61 predicted to render the protein more proapoptotic or at residue 156, which would inactivate the protein.
The G Glycoprotein of Respiratory Syncytial Virus Depresses Respiratory Rates through the CX3C Motif and Substance P
Authors: Tripp Ralph A. , Dakhama Azzeddine , Jones Les P. , Barskey Albert , Gelfand Erwin W. , Anderson Larry J. 
Published: May 2003

ABSTRACTRespiratory syncytial virus (RSV) infection in the neonate can alter respiratory rates, i.e., lead to episodes of apnea. We show that RSV G glycoprotein reduces respiratory rates associated with the induction of substance P (SP) and G glycoprotein-CX3CR1 interaction, an effect that is inhibited by treatment with anti-G glycoprotein, anti-SP, or anti-CX3CR1 monoclonal antibodies. These data suggest new approaches for treating some aspects of RSV disease.
What should a suspended doctor do when his actions could save a patient’s life?
Authors: Stewart J A D 
Published: May 2003

Abstract
Suspension from duty is becoming an increasing threat for medical practitioners. While under suspension a doctor may, in extreme circumstances, find themselves in a difficult legal dilemma as to their duty of care towards others. A suspended doctor may risk litigation if they are unaware of the legal ramifications of their unusual circumstances. The following article outlines the legal situation as it applies to England and Wales.
Chest radiographs in the emergency department: is the radiologist really necessary?
Authors: Gatt M E , Spectre G , Paltiel O , Hiller N , Stalnikowicz R 
Published: May 2003

Abstract

Background
The chest radiograph is considered one of the most complex imaging modalities to interpret. Several studies have evaluated radiograph interpretation in the emergency department, and considerable disagreement among clinical physicians and expert radiologists has been observed in the reading of chest films. The interpretation of chest radiographs by emergency department physicians was compared with senior radiologists in discharged patients, and misinterpretations assessed in relation to the physician’s level of training.

Methods
Radiological descriptions of 509 chest radiographs of 507 patients, aged 16–98 years who were discharged from the emergency department, were prospectively reviewed. Missed findings were recorded with regard to the physician’s level of training and experience. The effects of misinterpretations on discharge recommendations were also investigated. Statistical assessment was conducted using the χ2 test. Interobserver agreement was also tested by the κ coefficient.

Results
The sensitivity for detecting different abnormalities in the radiographs ranged from 20% to 64.9% and specificity from 94.9% to 98.7%. Despite the low sensitivities found, there were relatively few clinical implications of the “missed” findings since they were either of a minor nature or appropriate follow up was prescribed. The overall interobserver reliability, assessed by the κ coefficient, was 0.40 (95% confidence interval 0.35 to 0.46). These findings did not change significantly by emergency department physician’s level of training.

Conclusions
Emergency department physicians frequently miss specific radiographic abnormalities and there is considerable discrepancy between their interpretations and those of trained radiologists. These findings highlight the importance of routine evaluation of chest radiographs by a well trained radiologist and emphasise the need for improving interpretive skills among emergency department physicians.
Oral vitamin B12 can change our practice
Authors: Nyholm E , Turpin P , Swain D , Cunningham B , Daly S , Nightingale P , Fegan C 
Published: May 2003

Abstract
Oral vitamin B12 can provide an effective alternative to intramuscular injections, so giving patients a choice and reducing costs in primary care. This study investigated the effectiveness, safety, and acceptability of oral vitamin B12 as replacement therapy in patients with vitamin B12 deficiency in a city general practice population. Forty patients previously maintained on vitamin B12 injections were given 1000 μg of oral cyanocobalamin daily for up to 18 months. All the patients maintained satisfactory serum B12 levels and showed normal haematology and neurology. Compliance and acceptability was excellent. The time for a change in practice has indeed arrived.
Lack of Prognostic Significance of Early Elevated Serum Uric Acid Levels in Low Birthweight Infants
Authors: Sysyn Gregory D. , Rozycki Henry J. 
Published: May 2003

This study examined the utility of serum uric acid concentrations in the first day of life to identify infants with severe brain injury (grade III or IV intraventricular hemorrhage and/or periventricular leukomalacia). The serum uric acid concentrations in infants with severe brain injury were compared to those without. Severe brain injury was assessed in 151 infants with birthweight ≤1,251 g admitted before 24 h of life. The risk of severe brain injury was related to 5-min Apgar scores (odds ratio 0.79, CI 0.63–0.98, p < 0.05) and seizures in the first day of life (odds ratio 4.44, CI 1.004–19.66, p < 0.05), but the mean uric acid levels did not differ between those with and without severe brain injury [5.11 ± 1.88 mg/dl (303.9 ± 111.8 µmol/l) vs. 5.77 ± 2.13 mg/dl (343.2 ± 126.7 µmol/l), p = 0.200]. Uric acid levels were related to serum creatinine (p < 0.001), time of uric acid sample (p < 0.001), maternal hypertension (p < 0.001), and base deficit (p = 0.032). Of the 80 infants seen in neurodevelopmental follow-up at a median 11 months postconceptional age, uric acid concentrations did not differ between the abnormal (n = 20) and normal subjects [5.38 ± 1.72 mg/dl (320.0 ± 102.3 µmol/l) vs. 6.02 ± 2.55 mg/dl (358.1 ± 151.8 µmol/l), p = 0.197]. Uric acid may not be a useful early marker for premature infants with severe brain injury.
Phase II Trial of ZD1839 in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck
Authors: Cohen Ezra E. W. , Rosen Fred , Stadler Walter M. , Recant Wendy , Stenson Kerstin , Huo Dezheng , Vokes Everett E. 
Published: May 2003

Purpose: The epidermal growth factor receptor (EGFR) is a mediator of squamous cell carcinoma of the head and neck (SCCHN) development. ZD1839 is an orally active, selective EGFR tyrosine kinase inhibitor. This phase II study sought to explore the activity, toxicity, and pharmacodynamics of ZD1839 in SCCHN. Patients and Methods: Patients with recurrent or metastatic SCCHN were enrolled through the University of Chicago Phase II Consortium. Patients were allowed no more than one prior therapy for recurrent or metastatic disease and were treated with single-agent ZD1839 500 mg/d. Patient tumor biopsies were obtained and stained immunohistochemically for EGFR, extracellular signal-regulated kinase 1 (ERK1), and phosphorylated ERK1 (p-ERK). Study end points included response rate, time to progression, median survival, and inhibition of p-ERK. Results: Fifty-two patients were enrolled (40 male and 12 female) with a median age of 59 years (range, 34 to 84 years). Fourteen patients received ZD1839 through a feeding tube. Half the cohort received ZD1839 as second-line therapy. Forty-seven patients were assessable for response, with an observed response rate of 10.6% and a disease control rate of 53%. Median time to progression and survival were 3.4 and 8.1 months, respectively. The only grade 3 toxicity encountered was diarrhea in three patients. Performance status and development of skin toxicity were found to be strong predictors of response, progression, and survival. Ten biopsy samples were assessable and revealed no significant change in EGFR or p-ERK expression with ZD1839 therapy. Conclusion: ZD1839 has single-agent activity and is well tolerated in refractory SCCHN. In contrast to other reports, development of skin toxicity was a statistically significant predictor of response and improved outcome.
Male patient with non‐mosaic deleted Y‐chromosome and clinical features of Turner syndrome
Authors: Graham B.H. , Bacino C.A. 
Published: May 2003

AbstractTurner syndrome is hypothesized to result from haplo‐insufficency of a gene or perhaps multiple genes present on the sex chromosomes; however, the frequent association of mosaicism with deletions of the sex chromosomes prevents establishing useful genotype/phenotype correlations. In this clinical report, we present a male with a de novo, non‐mosaic deletion of the Y‐chromosome. The phenotype of this patient is unlike any similar cases previously reported in the literature. This patient exhibits many classical clinical features of Turner syndrome including short stature, characteristic facial anomalies, and webbed neck with low posterior hairline, aortic valve abnormality, and hearing impairment. Detailed molecular characterization of this deleted Y‐chromosome could provide important information towards establishing genotype/phenotype correlations in Turner syndrome. © 2003 Wiley‐Liss, Inc.