bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of sleep loss on next day effort
Authors: Engle‐Friedman Mindy , Riela Suzanne , Golan Rama , Ventuneac Ana M. , Davis Christine M. , Jefferson Angela D. , Major Donna
Published: May 2003

The study had two primary objectives. The first was to determine whether sleep loss results in a preference for tasks demanding minimal effort. The second was to evaluate the quality of performance when participants, under conditions of sleep loss, have control over task demands. In experiment 1, using a repeated‐measures design, 50 undergraduate college students were evaluated, following one night of no sleep loss and one night of sleep loss. The Math Effort Task (MET) presented addition problems via computer. Participants were able to select additions at one of five levels of difficulty. Less‐demanding problems were selected and more additions were solved correctly when the participants were subject to sleep loss. In experiment 2, 58 undergraduate college students were randomly assigned to a no sleep deprivation or a sleep deprivation condition. Sleep‐deprived participants selected less‐demanding problems on the MET. Percentage correct on the MET was equivalent for both the non‐sleep‐deprived and sleep‐deprived groups. On a task selection question, the sleep‐deprived participants also selected significantly less‐demanding non‐academic tasks. Increased sleepiness, fatigue, and reaction time were associated with the selection of less difficult tasks. Both groups of participants reported equivalent effort expenditures; sleep‐deprived participants did not perceive a reduction in effort. These studies demonstrate that sleep loss results in the choice of low‐effort behavior that helps maintain accurate responding.
Computerized calculation scheme for bitoric eikonic intraocular lenses
Authors: Langenbucher Achim , Seitz Berthold
Published: May 2003

Despite full correction of the corneal astigmatism with toric intraocular lenses, the retinal image is distorted and the lateral image‐object magnification is different in different meridians. The purpose of this study is to describe an iteration strategy for tracing an axial pencil of rays through the ‘optical system eye’ containing astigmatic refractive surfaces with their axes at random to calculate a thick bitoric lens implant which eliminates image distortion. The capabilities of this computing scheme are demonstrated with two clinical examples. We present a mathematically straightforward computer‐based strategy for the calculation of thick bitoric eikonic lens implants. The iteration algorithm is initialized with a spherical front and a toric back surface and stepwise decreases the image distortion by adding cylinder lenses to the front lens surface corrected by the toric lens back surface. Total magnification can be modulated by varying the front‐to‐back surface power of the thick lens.
Open‐ and closed‐loop regressions compared in myopic and emmetropic subjects
Authors: Hazel Charlotte A. , Strang Niall C. , Vera‐Díaz Fuensanta A.
Published: May 2003

Post‐near task accommodation regressions have been measured in a number of studies to investigate the association between myopia and nearwork. The slow nature of the regression found when measuring both open‐ and closed‐loop regressions in some subjects has been hypothesised to be associated with myopia development and progression. However, it is not known whether the speed and characteristics of the regression for an individual is the same under open‐ and closed‐loop conditions. In this study we measured post‐near task accommodation regression functions under open‐ and closed‐loop conditions for myopic and emmetropic subjects. We compared the responses of each subject under the two conditions and found that some subjects responded differently depending on the condition (i.e. a fast regression under one condition and a slow regression under the other condition). When compared as a group, the myopic subjects showed significantly more prolonged open‐loop regressions than closed‐loop regressions. In terms of the effect on the post‐task accommodation, the myopes appear to be more affected by the measurement conditions than the emmetropes in this study. The results highlight the importance of the type of accommodation stimulus when investigating the accommodation response.
From Molecules to Networks: Cortical/Subcortical Interactions in the Pathophysiology of Idiopathic Generalized Epilepsy
Authors: Blumenfeld Hal
Published: May 2003

Summary: Generalized epilepsy involves abnormally synchronized activity in large‐scale neuronal networks. Burst firing of action potentials is a potent mechanism for increasing neural synchrony and is thought to enhance cortical and thalamic rhythmic network activity. Absence seizures, a form of generalized epilepsy, occur in children as brief 5‐ to 10‐s periods of behavioral arrest associated with massive 3‐ to 4‐Hz spike‐wave discharges in cortical and thalamic networks. Prior research has shown that enhanced burst firing may be crucial for the transition from normal to epileptic activity. Can enhanced burst firing in one region of the nervous system, such as the cortex, transform the entire thalamocortical network from normal activity to spike‐and‐wave seizures? Enhanced burst firing in corticothalamic neurons may increase γ‐aminobutyric acid‐B (GABAB) receptor activation in the thalamus, leading to the slower, more synchronous oscillations seen in spike‐and‐wave seizures. Does “generalized” spike‐wave activity homogeneously involve the entire brain, or are there crucial nodes that are more important than others for the generation and behavioral manifestations of generalized seizures? Animal and human data suggest that so‐called generalized seizures involve selective thalamocortical networks while sparing others. A greater understanding of these molecular and network mechanisms will ultimately lead to improved targeted therapies for generalized epilepsy.
Overview: Idiopathic Generalized Epilepsies
Authors: Mattson Richard H.
Published: May 2003

Summary: The idiopathic generalized epilepsies (IGEs) are an underemphasized topic. Two reasons for this relative lack of attention are that these epilepsies tend to be more easily controlled than the symptomatic partial and generalized epilepsies, and they are not as common. Because IGE usually arises in childhood or adolescence, these epilepsies may be thought of as a pediatric problem. However, a large number of patients continue to have seizures in adult life. Many exciting developments in understanding the pathophysiology, genetic etiology, and expanded treatment options warrant a reexamination of this important group of the epilepsies. This article reviews the more common IGE syndromes and associated seizure types as the first step in identifying the recent advances in our knowledge of these syndromes.
Atrial Tachycardia Arising from an Epicardial Site with Venous Connection Between the Left Superior Pulmonary Vein and Superior Vena Cava
Authors: Tse Hung‐Fat , Lau Chu‐Pak , Lee Kathy L.F. , Morady Fred
Published: May 2003

We describe a case of atrial tachycardia originating from an epicardial site with a venous connection between the left superior pulmonary vein (LSPV) and superior vena cava (SVC). Initial endocardial mapping with multiple electrodes catheters demonstrated early endocardial activation at both the SVC and LSPV. However, radiofrequency applications at the SVC failed to terminate the atrial tachycardia. With three‐dimensional electroanatomic mapping, the earliest endocardial activation was found to be in the left atrial appendage (LAA). However, radiofrequency energy applications at multiple sites in the LAA resulted in only transient termination of the tachycardia. A left atrial angiogram demonstrated a venous connection between the LSPV and SVC, overlying the LAA. An application of radiofrequency energy with a saline‐irrigated ablation catheter delivered at the earliest activation site in the LAA terminated the tachycardia. The tachycardia did not recur during 18‐month follow‐up.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 540‐543, May 2003)
A Simple Method to Identify Sleep Apnea Using Holter Recordings
Authors: Stein Phyllis K. , Duntley Stephen P. , Domitrovich Peter P. , Nishith Pallavi , Carney Robert M.
Published: May 2003

Introduction: Despite its severe cardiovascular and other consequences, sleep apnea syndrome frequently is undiagnosed. Because apneas result in repeated autonomic arousals associated with cyclic variations in heart rate (CVHR), we hypothesized that sleep apnea syndrome could be identified from simple HR tachograms (graphs of HR vs time) derived from ECG monitoring.

Methods and Results: HR tachograms were generated from 57 digitized ECGs (46 clinical patients undergoing diagnostic studies and 11 research subjects) obtained during overnight polysomnography. Thirty‐three had significant sleep apnea syndrome (apnea‐hypopnea index ≥15). Eight patients had simultaneous Holter recordings during sleep studies (3 with digitized ECGs and 5 with paper ECGs). Duration of CVHR on tachograms was determined. CVHR patterns were characterized as high amplitude (HR changes ≥20 beats/min per cycle) versus lower amplitude (6–19 beats/min per cycle); or regular (in frequency, amplitude, and morphology) versus irregular. Tachograms were classified as having visible HR changes versus not visible (flat). Twenty‐four studies proved to be split‐night, so CVHR was quantified for the first 3 hours of each study only. When subjects were dichotomized into shorter (<20%, <36 min) and longer (≥20%) durations of CVHR, longer CVHR had a positive predictive accuracy of 86% for significant sleep apnea syndrome and 100% for abnormal sleep. When flat tachograms were excluded, negative predictive accuracy for shorter CVHR was 100%. All patients

(N = 13)

with >36 min high‐amplitude CVHR had significant obstructive sleep apnea. All predictions from Holter‐only data were concordant with clinical diagnoses.

Conclusion: HR tachogram patterns derived from ambulatory ECGs provide a simple method for identifying sleep apnea syndrome and other sleep disturbances in patients without major autonomic dysfunction.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 467‐473, May 2003)
Novel Concept of Atrial Tachyarrhythmias Originating from the Superior Vena Cava:
Authors: Liu Tu‐Ying , Tai Ching‐Tai , Lee Pi‐Chang , Hsieh Ming‐Hsiung , Higa Satoshi , Ding Yu‐An , Chen Shih‐Ann
Published: May 2003

Introduction: Information about the activation patterns inside the superior vena cava (SVC) and entry and exit sites at the SVC‐right atrial (RA) junction during SVC tachyarrhythmia is limited.

Methods and Results: A detailed characterization of electrophysiologic mechanisms and ablation strategies was performed using a noncontact three‐dimensional mapping system in two cases of SVC tachycardia. The first case demonstrated SVC tachycardia originating from an ectopic focus inside the SVC, with sustained depolarization and conduction to the atrium. Entry and exit sites across the SVC‐RA junction were located very close to each other. The second case demonstrated two different reentrant circuits, one inside the SVC and the other into and out of the SVC‐RA junction. The entry and exit sites were located far away from each other.

Conclusion: Noncontact mapping may help to reveal the mechanism of SVC tachyarrhythmias and to locate entry and exit sites at the SVC‐RA junction as a guide for catheter ablation.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 533‐539, May 2003)
Natural History of Brugada Syndrome:
Authors: Brugada Pedro , Brugada Ramon , Mont Lluis , Rivero Maximo , Geelen Peter , Brugada Josep
Published: May 2003

Introduction: The prognostic value of electrophysiologic studies in individuals with the syndrome of right bundle branch block and ST segment elevation in precordial leads V1 to V3 (Brugada syndrome) remains controversial. Our previous data from 252 individuals with the syndrome suggested that programmed ventricular stimulation had a good overall accuracy to predict events. However, studies from independent investigators questioned our results. We report here the largest population with Brugada syndrome ever studied by programmed electrical stimulation of the heart.

Methods and Results: Four hundred forty‐three individuals with an ECG diagnostic of Brugada syndrome were studied by programmed electrical stimulation of the heart. The diagnosis was made because of the classic ECG showing a coved‐type ST segment elevation in precordial leads V1 to V3. Of the 443 individuals, 180 had developed spontaneous symptoms (syncope or aborted sudden cardiac death) and 263 were asymptomatic at the time the diagnosis was made. The ventricular stimulation protocol included a minimum of two basic pacing cycle lengths with two ventricular premature beats from the right ventricular apex. A sustained ventricular arrhythmia was induced in 217 cases (49%). Symptomatic patients were more frequently inducible [126/180 (70%)] than asymptomatic individuals [91/263 (34%);

P = 0.0001

]. Males were more frequently inducible than females (54% vs 32%,

P < 0.0001

). Inducible individuals had a longer HV interval than noninducible patients (

50 ± 12 msec

vs

46 ± 10 msec, P < 0.002

). HV interval and number of premature beats needed to induce VF were not related to outcome. Inducibility was statistically a powerful predictor of arrhythmic events during follow‐up. Sixty of 217 inducible patients (28%) had spontaneous ventricular fibrillation compared with 5 of 221 noninducible patients

(2%; P = 0.0001)
.

Conclusion: Inducibility of sustained ventricular arrhythmias during programmed ventricular stimulation of the heart is a good predictor of outcome in Brugada syndrome.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 455‐457, May 2003)
Androgen-stimulated DNA synthesis and cytoskeletal changes in fibroblasts by a nontranscriptional receptor action
Authors: Castoria Gabriella , Lombardi Maria , Barone Maria Vittoria , Bilancio Antonio , Di Domenico Marina , Bottero Daniela , Vitale Flavia , Migliaccio Antimo , Auricchio Ferdinando
Published: May 2003

In NIH3T3 cells, 0.001 nM of the synthetic androgen R1881 induces and stimulates association of androgen receptor (AR) with Src and phosphatidylinositol 3-kinase (Pl3-kinase), respectively, thereby triggering S-phase entry. 10 nM R1881 stimulates Rac activity and membrane ruffling in the absence of the receptor–Src–PI3-kinase complex assembly. The antiandrogen Casodex and specific inhibitors of Src and PI3-kinase prevent both hormonal effects, DNA synthesis and cytoskeletal changes. Neither low nor high R1881 concentration allows receptor nuclear translocation and receptor-dependent transcriptional activity in fibroblasts, although they harbor the classical murine AR. The very low amount of AR in NIH3T3 cells (7% of that present in LNCaP cells) activates the signaling pathways, but apparently is not sufficient to stimulate gene transcription. This view is supported by the appearance of receptor nuclear translocation as well as receptor-mediated transcriptional activity after overexpression of AR in fibroblasts. In addition, AR-negative Cos cells transiently transfected with a very low amount of hAR cDNA respond to low and high R1881 concentrations with signaling activation. Interestingly, they do not show significant transcriptional activation under the same experimental conditions. Fibroblasts are the first example of cells that respond to steroid hormones with activation of signaling pathways in the absence of endogenous receptor transcriptional activity. The data reported also show that hormone concentration can be crucial in determining the type of cell responsiveness.
Mitochondria to nucleus stress signaling
Authors: Biswas Gopa , Anandatheerthavarada Hindupur K. , Zaidi Mone , Avadhani Narayan G.
Published: May 2003

Mitochondrial genetic and metabolic stress causes activation of calcineurin (Cn), NFAT, ATF2, and NFκB/Rel factors, which collectively alter the expression of an array of nuclear genes. We demonstrate here that mitochondrial stress–induced activation of NFκB/Rel factors involves inactivation of IκBβ through Cn-mediated dephosphorylation. Phosphorylated IκBβ is a substrate for Cn phosphatase, which was inhibited by FK506 and RII peptide. Chemical cross-linking and coimmunoprecipitation show that NFκB/Rel factor–bound IκBβ forms a ternary complex with Cn under in vitro and in vivo conditions that was sensitive to FK506. Results show that phosphorylation at S313 and S315 from the COOH-terminal PEST domain of IκBβ is critical for binding to Cn. Mutations at S313/S315 of IκBβ abolished Cn binding, inhibited Cn-mediated increase of Rel proteins in the nucleus, and had a dominant-negative effect on the mitochondrial stress–induced expression of RyR1 and cathepsin L genes. Our results show the distinctive nature of mitochondrial stress–induced NFκB/Rel activation, which is independent of IKKα and IKKβ kinases and affects gene target(s) that are different from cytokine and TNFα-induced stress signaling. The results provide new insights into the role of Cn as a critical link between Ca2+ signaling and NFκB/Rel activation.
Spindle orientation in Saccharomyces cerevisiae depends on the transport of microtubule ends along polarized actin cables
Authors: Hwang Eric , Kusch Justine , Barral Yves , Huffaker Tim C.
Published: May 2003

Microtubules and actin filaments interact and cooperate in many processes in eukaryotic cells, but the functional implications of such interactions are not well understood. In the yeast Saccharomyces cerevisiae, both cytoplasmic microtubules and actin filaments are needed for spindle orientation. In addition, this process requires the type V myosin protein Myo2, the microtubule end–binding protein Bim1, and Kar9. Here, we show that fusing Bim1 to the tail of the Myo2 is sufficient to orient spindles in the absence of Kar9, suggesting that the role of Kar9 is to link Myo2 to Bim1. In addition, we show that Myo2 localizes to the plus ends of cytoplasmic microtubules, and that the rate of movement of these cytoplasmic microtubules to the bud neck depends on the intrinsic velocity of Myo2 along actin filaments. These results support a model for spindle orientation in which a Myo2–Kar9–Bim1 complex transports microtubule ends along polarized actin cables. We also present data suggesting that a similar process plays a role in orienting cytoplasmic microtubules in mating yeast cells.
Inventories to insights
Authors: Aitchison John D. , Galitski Timothy
Published: May 2003

“In the long course of cell life on this earth it remained, for our age, for our generation, to receive the full ownership of our inheritance. We have entered the cell, the Mansion of our birth and started the inventory of our acquired wealth.” (Albert Claude, Nobel lecture, 1974)
Holey barrier
Authors: Matter Karl , Balda Maria S.
Published: May 2003

Endothelial tight junctions (TJs)**Abbreviations used in this paper: BBB, blood-brain barrier; BEC, brain endothelial cell; TJ, tight junction. are an important functional part of the blood-brain barrier (BBB). In this issue, Nitta et al. (2003) demonstrate that claudin-5, a transmembrane protein of TJs, is a critical determinant of BBB permeability in mice. Unexpectedly, knockout of claudin-5 did not result in a general breakdown of TJs but in a selective increase in paracellular permeability of small molecules. This suggests that the BBB can be manipulated to allow selective diffusion of small molecules and makes claudin-5 a possible target for the development of drugs for this purpose.
Attitudes towards Taxation: Ignorant and Incoherent?
Authors: Edlund Jonas
Published: May 2003

The point of departure for this paper is US evidence claiming that citizens do not possess an adequate understanding of the concept of progressive taxation. Using the format of standard survey questions, most respondents preferred progressive taxes. When faced with similar questions framed in concrete terms, a majority rejected progressive taxes. By analysing data from Sweden, it is shown that irrespective of whether abstract or concrete measures are applied, most citizens support progressive taxation. There is no evidence indicating that Swedes in general do not understand the concept of progressive taxation. To explain why US citizens are more ignorant about progressive taxation than Swedish citizens, it is suggested that the Swedish welfare state institutions and the surrounding political environment may be exercising a substantially stronger educational influence on the meaning of redistributive concepts.
Complete Sequence and Comparative Analysis of the Genome of Herpes B Virus (
Cercopithecine Herpesvirus 1
) from a Rhesus Monkey
Authors: Perelygina Ludmila , Zhu Li , Zurkuhlen Holley , Mills Ryan , Borodovsky Mark , Hilliard Julia K.
Published: May 2003

The complete DNA sequence of herpes B virus
(Cercopithecine herpesvirus 1)
strain E2490, isolated from a rhesus macaque, was determined. The total genome length is 156,789 bp, with 74.5% G+C composition and overall genome organization characteristic of alphaherpesviruses. The first and last residues of the genome were defined by sequencing the cloned genomic termini. There were six origins of DNA replication in the genome due to tandem duplication of both
oriL
and
oriS
regions. Seventy-four genes were identified, and sequence homology to proteins known in herpes simplex viruses (HSVs) was observed in all cases but one. The degree of amino acid identity between B virus and HSV proteins ranged from 26.6% (US5) to 87.7% (US15). Unexpectedly, B virus lacked a homolog of the HSV γ
1
34.5 gene, which encodes a neurovirulence factor. Absence of this gene was verified in two low-passage clinical isolates derived from a rhesus macaque and a zoonotically infected human. This finding suggests that B virus most likely utilizes mechanisms distinct from those of HSV to sustain efficient replication in neuronal cells. Despite the considerable differences in G+C content of the macaque and B virus genes (51% and 74.2%, respectively), codons used by B virus are optimal for the tRNA population of macaque cells. Complete sequence of the B virus genome will certainly facilitate identification of the genetic basis and possible molecular mechanisms of enhanced B virus neurovirulence in humans, which results in an 80% mortality rate following zoonotic infection.
Resolution of Parvovirus Dimer Junctions Proceeds through a Novel Heterocruciform Intermediate
Authors: Cotmore Susan F. , Tattersall Peter
Published: May 2003

The minute virus of mice initiator protein, NS1, excises new copies of the left viral telomere in a single sequence orientation, dubbed flip, during resolution of the junction between monomer genomes in palindromic dimer intermediate duplexes. We examined this reaction in vitro using both
32
P-end-labeled linear substrates and similar unlabeled templates labeled by incorporation of [α-
32
P]TTP during the synthesis. The observed products suggest a resolution model that explains conservation of the hairpin sequence and in which a novel heterocruciform intermediate plays a crucial role. In vitro, NS1 initiates two replication pathways from OriL
TC
, the single active origin embedded in one arm of the dimer junction. NS1-mediated nicking liberates a base-paired 3′ nucleotide to prime DNA synthesis and, in a reaction we call “read-through synthesis,” forks established while the substrate is a linear duplex synthesize DNA in the flop orientation, leading to DNA amplification but not to junction resolution. Nicking leaves NS1 covalently attached to the 5′ end of the DNA, where it can serve as a 3′-to-5′ helicase, unwinding the NS1-associated strand. In the second pathway, resolution substrates are created when such unwinding induces the palindrome to reconfigure into a cruciform prior to fork assembly. New forks can then synthesize DNA in the flip orientation, copying one cruciform arm and creating a heterocruciform intermediate. Resolution proceeds via hairpin transfer in the extended arm of the heterocruciform, which releases one covalently closed duplex telomere and a partially single-stranded junction intermediate. We suggest that the latter intermediate is finally resolved via an NS1-induced single-strand nick at the otherwise inactive origin, OriL
GAA
.
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

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

Theiler'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

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

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

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

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

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

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

Respiratory 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

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

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

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.
How Do Cells Know What They Want to Be When They Grow Up? Lessons from Epidermal Patterning in Arabidopsis
Authors: Larkin John C. , Brown Matt L. , Schiefelbein John
Published: May 2003

Because the plant epidermis is readily accessible and consists of few cell types on most organs, the epidermis has become a well-studied model for cell differentiation and cell patterning in plants. Recent advances in our understanding of the development of three epidermal cell types, trichomes, root hairs, and stomata, allow a comparison of the underlying patterning mechanisms. In Arabidopsis, trichome development and root epidermal patterning use a common mechanism involving closely related cell fate transcription factors and a similar lateral inhibition signaling pathway. Yet the resulting patterns differ substantially, primarily due to the influence of a prepattern derived from subepidermal cortical cells in root epidermal patterning. Stomatal patterning uses a contrasting mechanism based primarily on control of the orientation of cell divisions that also involves an inhibitory signaling pathway. This review focuses on comparing and contrasting these patterning pathways to identify and illustrate general themes that may be broadly applicable to other systems. Where these pathways occur in the same tissue, interaction and competition between these pathways is also discussed.
The Plant Cell Cycle
Authors: Dewitte Walter , Murray James A.H.
Published: May 2003

Cell division in plants is controlled by the activity of cyclin-dependent kinase (CDK) complexes. Although this basic mechanism is conserved with all other eukaryotes, plants show novel features of cell-cycle control in the molecules involved and their regulation, including novel CDKs showing strong transcriptional regulation in mitosis. Plant development is characterized by indeterminate growth and reiteration of organogenesis and is therefore intimately associated with cell division. This may explain why plants have a large number of cell-cycle regulators that appear to have overlapping and distinct functions. Here we review the recent considerable progress in understanding how core cell-cycle regulators are involved in integrating and coordinating cell division at the molecular level.
The COP9 Signalosome: Regulating Plant Development Through the Control of Proteolysis
Authors: Serino Giovanna , Deng Xing-Wang
Published: May 2003

The COP9 signalosome (CSN) is a multiprotein complex that was initially identified in plants as a repressor of photomorphogenesis. It is now known to play major roles in several other developmental pathways, from auxin response to flower development. Furthermore, the COP9 signalosome shares homologies with the lid sibcomplex of the proteasome and is evolutionarily conserved from fission yeast to humans. It is important for the proper development of virtually all higher eukaryotes. In recent years, significant progress has been made in unraveling the molecular, cellular, and physiological mode of action of the COP9 signalosome. This review discusses our current understanding of the COP9 signalosome function with particular emphasis on its recently defined role in modulating a wide variety of cellular processes by regulating specific protein degradation events.
Structure of Linkage Disequilibrium in Plants
Authors: Flint-Garcia Sherry A. , Thornsberry Jeffry M. , Buckler Edward S.
Published: May 2003

Future advances in plant genomics will make it possible to scan a genome for polymorphisms associated with qualitative and quantitative traits. Before this potential can be realized, we must understand the nature of linkage disequilibrium (LD) within a genome. LD, the nonrandom association of alleles at different loci, plays an integral role in association mapping, and determines the resolution of an association study. Recently, association mapping has been exploited to dissect quantitative trait loci (QTL). With the exception of maize and Arabidopsis, little research has been conducted on LD in plants. The mating system of the species (selfing versus outcrossing), and phenomena such as population structure and recombination hot spots, can strongly influence patterns of LD. The basic patterns of LD in plants will be better understood as more species are analyzed.