bluuebunny/crossref_metadata_2025 huggingface dataset:
A sense phosphorothioate oligodeoxynucleotide containing the transforming growth factor beta regulatory element acts as a novel local nonsteroidal antifibrotic drug
Authors: Cutroneo Kenneth R
Published: January 2004

Fibrosis is a potential response to tissue injury. At present, glucocorticoids with their numerous toxic side effects are the only effective treatment for fibrotic diseases. Granulomas induced by sponge implantation were treated with single‐stranded phosphorothioate oligodeoxynucleotides containing the wild type or mutated transforming growth factor‐β response element designed to inhibit the rat proα1(I) promoter activity. Single‐stranded phosphorothioate oligonucleotides resulted in antifibrotic activity based on their ability to reduce granuloma tissue formation and selectively inhibit collagen synthesis. The mutated single‐standed phosphorothioate oligonucleotides or dexamethasone given at an equivalent dose to single‐standed phosphorothioate oligonucleotides failed to do so. These data suggest that the phosphorothioate oligodeoxynucleotide containing the transforming growth factor‐β regulatory element has an antifibrotic effect and may be used to inhibit the development of fibrosis.
Endogenous Liquidity in Asset Markets
Authors: Eisfeldt Andrea L.
Published: January 2004

This paper analyzes a model in which long‐term risky assets are illiquid due to adverse selection. The degree of adverse selection and hence the liquidity of these assets is determined endogenously by the amount of trade for reasons other than private information. I find that higher productivity leads to increased liquidity. Moreover, liquidity magnifies the effects of changes in productivity on investment and volume. High productivity implies that investors initiate larger scale risky projects which increases the riskiness of their incomes. Riskier incomes induce more sales of claims to high‐quality projects, causing liquidity to increase.
Price Pressure around Mergers
Authors: Mitchell Mark , Pulvino Todd , Stafford Erik
Published: January 2004

This paper examines the trading behavior of professional investors around 2,130 mergers announced between 1994 and 2000. We find considerable support for the existence of price pressure around mergers caused by uninformed shifts in excess demand, but that these effects are short‐lived, consistent with the notion that short‐run demand curves for stocks are not perfectly elastic. We estimate that nearly half of the negative announcement period stock price reaction for acquirers in stock‐financed mergers reflects downward price pressure caused by merger arbitrage short selling, suggesting that previous estimates of merger wealth effects are biased downward.
Bondholder Wealth Effects in Mergers and Acquisitions: New Evidence from the 1980s and 1990s
Authors: Billett Matthew T. , King Tao‐Hsien Dolly , Mauer David C.
Published: January 2004

We examine the wealth effects of mergers and acquisitions on target and acquiring firm bondholders in the 1980s and 1990s. Consistent with a coinsurance effect, below investment grade target bonds earn significantly positive announcement period returns. By contrast, acquiring firm bonds earn negative announcement period returns. Additionally, target bonds have significantly larger returns when the target's rating is below the acquirer's, when the combination is anticipated to decrease target risk or leverage, and when the target's maturity is shorter than the acquirer's. Finally, we find that target and acquirer announcement period bond returns are significantly larger in the 1990s.
Social Interaction and Stock‐Market Participation
Authors: Hong Harrison , Kubik Jeffrey D. , Stein Jeremy C.
Published: January 2004

We propose that stock‐market participation is influenced by social interaction. In our model, any given “social” investor finds the market more attractive when more of his peers participate. We test this theory using data from the Health and Retirement Study, and find that social households—those who interact with their neighbors, or attend church—are substantially more likely to invest in the market than non‐social households, controlling for wealth, race, education, and risk tolerance. Moreover, consistent with a peer‐effects story, the impact of sociability is stronger in states where stock‐market participation rates are higher.
Market Imperfections, Investment Flexibility, and Default Spreads
Authors: Titman Sheridan , Tompaidis Stathis , Tsyplakov Sergey
Published: January 2004

This paper develops a structural model that determines default spreads in a setting where the debt's collateral is endogenously determined by the borrower's investment choice, and a demand variable with permanent and temporary components. We also consider the possibility that the borrower cannot commit to taking the value‐maximizing investment choice, and may, in addition, be constrained in its ability to raise external capital. Based on a model calibrated to data on office buildings and commercial mortgages, we present numerical simulations that quantify the extent to which investment flexibility, incentive problems, and credit constraints affect default spreads.
Are Investors Rational? Choices among Index Funds
Authors: Elton Edwin J. , Gruber Martin J. , Busse Jeffrey A.
Published: January 2004

S&P 500 index funds represent one of the simplest vehicles for examining rational behavior. They hold virtually the same securities, yet their returns differ by more than 2 percent per year. Although the relative returns of alternative S&P 500 funds are easily predictable, the relationship between cash flows and performance is weaker than rational behavior would lead us to expect. We show that selecting funds based on low expenses or high past returns outperforms the portfolio of index funds selected by investors. Our results exemplify the fact that, in a market where arbitrage is not possible, dominated products can prosper.
Optimal Consumption and Investment with Transaction Costs and Multiple Risky Assets
Authors: Liu Hong
Published: January 2004

We consider the optimal intertemporal consumption and investment policy of a constant absolute risk aversion (CARA) investor who faces fixed and proportional transaction costs when trading multiple risky assets. We show that when asset returns are uncorrelated, the optimal investment policy is to keep the dollar amount invested in each risky asset between two constant levels and upon reaching either of these thresholds, to trade to the corresponding optimal targets. An extensive analysis suggests that transaction cost is an important factor in affecting trading volume and that it can significantly diminish the importance of stock return predictability as reported in the literature.
Informed Trading When Information Becomes Stale
Authors: Bernhardt Dan , Miao Jianjun
Published: January 2004

This paper characterizes informed trade when speculators can acquire distinct signals of varying quality about an asset's value at different dates. The most reasonable characterization of private information about stocks is that while information is long‐lived, new information will arrive over time, information that may be acquired by others. Hence, while a speculator may know more than others at a moment, in the future, his information will become stale, but not valueless. In an environment that allows for arbitrary correlations among signals, we characterize equilibrium outcomes including trading, prices, and profits. We provide explicit numerical characterizations for different informational environments.
Convertible Bond Design and Capital Investment: The Role of Call Provisions
Authors: Korkeamaki Timo P. , Moore William T.
Published: January 2004

If firms issue convertible securities to facilitate sequential investment, the securities should be engineered to give sufficient flexibility to accommodate timing of follow‐on investment. We examine call provisions in convertible bonds and argue that firms with investment options expected to expire sooner (later) will offer weaker (stronger) call protection. We find that issues with weak or no call protection are offered by firms that invest greater amounts soon after issuance than those issuing convertibles with strong protection. Moreover, capital expenditure levels during the 5‐year period following issuance are inversely related to the length of call‐protection periods.
Option‐Implied Risk Aversion Estimates
Authors: Bliss Robert R. , Panigirtzoglou Nikolaos
Published: January 2004

Using a utility function to adjust the risk‐neutral PDF embedded in cross sections of options, we obtain measures of the risk aversion implied in option prices. Using FTSE 100 and S&P 500 options, and both power and exponential‐utility functions, we estimate the representative agent's relative risk aversion (RRA) at different horizons. The estimated coefficients of RRA are all reasonable. The RRA estimates are remarkably consistent across utility functions and across markets for given horizons. The degree of RRA declines broadly with the forecast horizon and is lower during periods of high market volatility.
How Do Exchanges Select Stocks for Option Listing?
Authors: Mayhew Stewart , Mihov Vassil
Published: January 2004

We investigate the factors influencing the selection of stocks for option listing. Exchanges tend to list options on stocks with high trading volume, volatility, and market capitalization, but the relative effect of these factors has changed over time as markets have evolved. We observe a shift from volume toward volatility after the moratorium on new listings ended in 1980. Using control sample methodology designed to correct for the endogeneity of option listing, we find no evidence that volatility declines with option introduction, in contrast to previous studies that do not use control samples.
Involvement of tumor necrosis factor‐α and interleukin‐8 in antigen‐induced arthritis of the rabbit temporomandibular joint
Authors: Sukedai Miho , Tominaga Kazuhiro , Habu Manabu , Matsukawa Akihiro , Nishihara Tatsuji , Fukuda Jinichi
Published: January 2004

Background:  In temporomandibular joint (TMJ) arthritis, knowledge is limited about the source of the inflammatory mediators. The aim of this study was to investigate the immunohistochemical role of tumor necrosis factor‐α (TNF‐α) and interleukin‐8 (IL‐8) in the development of the antigen‐induced arthritis of the rabbit TMJ.

Methods:  Unilateral TMJ arthritis was induced in 28 adult rabbits. From 6 h to 6 weeks after induction of arthritis, the topology of TNF‐α and IL‐8 was observed.

Results:  Positive reaction for TNF‐α of synovial cells was observed within 3 days after induction and at 3 weeks after induction. TNF‐α positive vascular endothelial cells and chondrocytes were identified throughout the observation period. IL‐8 was detected only during the acute stage.

Conclusions:  The cytokines TNF‐α and IL‐8 were observed in specific cells depending on the stage. TNF‐α was particularly related with angiogenesis and cartilage destruction and IL‐8 was involved in the acute stage of inflammation.
Intraepithelial expression of perlecan, a basement membrane‐type heparan sulfate proteoglycan reflects dysplastic changes of the oral mucosal epithelium
Authors: Ikarashi Terué , Ida‐Yonemochi Hiroko , Ohshiro Kazufumi , Cheng Jun , Saku Takashi
Published: January 2004

Background:  Intercellular deposition of perlecan, a major heparan sulfate proteoglycan (HSPG) of the basement membrane, is known to result in characteristic stellate reticulum‐like structures in ameloblastomas or tooth germs. Although enlargement of the intercellular space is one of the histological characteristics of epithelial dysplasia of oral mucosa, the mode of expression of perlecan is poorly understood in these epithelial lesions.

Methods:  Eighty‐two biopsy specimens consisting of normal and hyperplastic epithelium, epithelial dysplasia, and squamous cell carcinomas were examined for both perlecan core protein and heparan sulfate (HS) chains by immunohistochemistry and in situ hybridization.

Results:  In normal and hyperplastic epithelium, perlecan core protein and HS chains were localized in the cell border of parabasal cells and lower prickle cells, and HS chains were also found in basal cells. With an increase in the severity of epithelial dysplasia, the core protein was heavily and extensively deposited in the interepithelial space as well as in the cytoplasm of epithelial cells from the basal to the surface layers. Its gene expression was confirmed in the cells around the protein deposits. On the other hand, HS chains were enhanced in mild dysplasia, but decreased in moderate and severe dysplasias. In squamous cell carcinomas, either the core protein or HS chains were found scarcely in tumor cells but abundantly in the stromal space.

Conclusions:  The findings indicate that perlecan is localized in the intercellular space of the oral epithelia, and that it is over‐expressed in dysplastic epithelial cells and is deposited in their interepithelial space, which results in the histology of reduction of cellular cohesion.
Primary intraosseous odontogenic carcinoma with osteoid/dentinoid formation
Authors: Punnya A. , Kumar G. S. , Rekha K. , Vandana R.
Published: January 2004

Primary intraosseous carcinoma/odontogenic carcinomas are extremely rare malignant odontogenic tumours that are thought to arise from residues of odontogenic epithelium. An unusual case of primary intraosseous carcinoma arising de novo in a previously unreported site of posterior maxilla is described. The tumour was characterized by sheets of pleomorphic round‐to‐ovoid cells and marked osteoid/dentinoid formation with foci of globular mineralization.
Establishment of OC3 oral carcinoma cell line and identification of NF‐κB activation responses to areca nut extract
Authors: Lin Shu‐Chun , Liu Chung‐Ji , Chiu Chun‐Po , Chang Shun‐Ming , Lu Suu‐Yi , Chen Yann‐Jang
Published: January 2004

Background:  Cell lines derived from oral squamous cell carcinoma (OSCC) exposed to variable etiological factors can bestow advantages in understanding the molecular and cellular alterations pertaining to environmental impacts. Most OSCC cell lines have been established from smoker patients or areca chewing/smoker patients, carrying the genomic alterations in p53.

Methods:  A new cell line, oral carcinoma 3 (OC3), was established from an OSCC in a long‐term areca (betel) chewer who does not smoke. Cellular and molecular features of OC3 were determined by variable assays.

Results:  The cultured monolayer cells were mainly polygonal and had the expression of cytokeratin 14. The chromosomal analysis using comparative genomic hybridization has revealed the gain in chromosomes 1q, 5q, and 8q, the loss in 4q, 6p, and 8p as well as the gain of entire chromosome 20. Loss of heterozygosity and instability in multiple microsatellite markers in chromosome 4q were also noted. OC3 cells bear wild‐type p53 coding sequence and have a high level of p53 expression. Its p21 expression was similar to that in normal human oral keratinocyte (NHOK). Interestingly, activation of nuclear factor κB (NF‐κB) in OC3 cells following the treatment of areca nut extract was observed.

Conclusion:  OC3 cell line could be valuable in understanding the genetic impairments and phenotypic changes associated with areca in oral keratinocyte.
Mdm2 mRNA expression in salivary gland tumour cell lines
Authors: Mantesso Andrea , Loducca Silvia Vanessa Lourenço , Bendit Israel , Garicochea Bernardo , Nunes Fabio Daumas , De Araújo Vera Cavalcanti
Published: January 2004

Background:  Murine double minute 2 (mdm2) is a cellular protooncogene, which, in conditions of overexpression or amplification, is capable of inactivating the functions of p53, leading to tumorigenesis. Immunoexpression of mdm2 in salivary gland tumours was previously found; however, it was necessary to find out if mdm2 was overexpressed. The aim of this study was to analyse the mRNA expression of mdm2 in salivary gland neoplasms and to correlate it to immunoexpression of p53 and p21 proteins.

Methods:  Specimens of different salivary gland neoplasms were obtained from surgical resections, and cell lineages derived from these tissues were established. RNA extraction was performed and mRNA expression was investigated using reverse transcription‐polymerase chain reaction (RT‐PCR). Cellular expression of p53 and p21 proteins was investigated by immunofluorescence technique.

Results:  Increased expression of mdm2 was found in the majority of cell lines analysed.

Conclusions:  Comparing all results, we postulated that overexpression of mdm2 is related to the tumorigenesis and/or tumour progression of salivary gland neoplasms.
Interobserver reliability in the histopathologic diagnosis of oral pre‐malignant and malignant lesions
Authors: Fischer Dena J. , Epstein Joel B. , Morton Thomas H. , Schwartz Stephen M.
Published: January 2004

Background: The histologic classification of pre‐cancerous and cancerous oral lesions has generally shown poor agreement between pathologists, but lesion and patient characteristics that may affect diagnostic reliability have not been explored.

Methods: Eighty‐seven clinically suspicious oral lesions biopsied from 81 patients with previous upper aerodigestive tract cancer were independently classified by their local pathologist and a central pathology committee. Interobserver reliability between the local pathologist and the central pathology committee was measured with weighted kappa (κw) statistics and corresponding 95% confidence intervals (CI).

Result: Theκwfor pathologic diagnosis was 0.59 (95% CI: 0.45, 0.72), and was higher for lesions without inflammation (0.67 (95% CI: 0.53, 0.80) than inflamed lesions (−0.10 (95% CI: −0.27, 0.07)). Greatest agreement was seen for lesions located in the buccal mucosa/vestibule (κw = 0.68 (95% CI: 0.46, 0.91)) and tongue (κw = 0.62 (95% CI: 0.40, 0.84)). Least agreement was found for lip/labial mucosa lesions (κw = −0.04 (95% CI: −0.34, 0.27)). Punch biopsies (κw = 0.67 (95% CI: 0.54, 0.80)) had greater interobserver reliability than wedge biopsies (κw = 0.38 (95% CI: 0.12, 0.64)).

Conclusions: These data suggest that the presence of inflammation, lesion site, and biopsy technique modifies the reliability of oral lesion histologic diagnoses.
Systemic capsaicin for burning mouth syndrome: short‐term results of a pilot study
Authors: Petruzzi Massimo , Lauritano Dorina , De Benedittis Michele , Baldoni Marco , Serpico Rosario
Published: January 2004

Background:  Burning mouth syndrome (BMS) is a major diagnostic and therapeutic problem. Systemic and topical treatments (capsaicin, lidocaine, anti‐histamines, sucralfate and benzydiamine) have been tried, but they appear to be inadequate. Topical capsaicin is bitter, may cause burning and has low therapeutic efficacy. We hypothesized that systemic administration of capsaicin could reduce the limitations of topical administration and have better therapeutic efficacy; this hypothesis was tested in a controlled trial.

Methods:  Systemic oral capsaicin 0.25% was used for patients with BMS, recruited in our single centre. After the diagnosis of BMS, patients were dentally and medically examined. They were alternatively assigned to treatment with capsaicin or to a shape/smell/taste/color matched placebo. The severity of symptoms was scored at trial entry and 30 days thereafter by investigators who were unaware of the assigned intervention. The visual analogical scale (VAS) measure was used to score the severity of pain, and results for the treated and untreated groups were compared by Fisher's exact test. Analysis was performed by intention‐to‐treat. Statistical significance was considered for values of P < 0.05. Data are expressed as mean ± SD.

Results:  Fifty patients were enrolled (25 assigned to systemic capsaicin and 25 to placebo). The VAS score was significantly lower in treated patients (5.84 ± 1.17) as compared to the placebo‐control group (6.24 ± 0.96). The use of systemic capsaicin implied significant gastric toxicity (referred gastric pain) with eight cases (32%) documented in the treatment group as compared to zero cases (0%) in the placebo control group.

Conclusion:  Systemic capsaicin is therapeutically effective for the short‐term treatment of BMS but major gastrointestinal side‐effects may threaten its large‐scale, long‐term use. This preliminary study suggests that more, adequately powered, randomized controlled trials are necessary and worthy to come to a definitive assessment of this matter.
Instructive Role of Wnt/ß-Catenin in Sensory Fate Specification in Neural Crest Stem Cells
Authors: Lee Hye-Youn , Kléber Maurice , Hari Lisette , Brault Véronique , Suter Ueli , Taketo Makoto M. , Kemler Rolf , Sommer Lukas
Published: January 2004

Wnt signaling has recently emerged as a key factor in controlling stem cell expansion. In contrast, we show here that Wnt/β-catenin signal activation in emigrating neural crest stem cells (NCSCs) has little effect on the population size and instead regulates fate decisions. Sustained β-catenin activity in neural crest cells promotes the formation of sensory neural cells in vivo at the expense of virtually all other neural crest derivatives. Moreover, Wnt1 is able to instruct early NCSCs (eNCSCs) to adopt a sensory neuronal fate in a β-catenin–dependent manner. Thus, the role of Wnt/β-catenin in stem cells is cell-type dependent.
A Double-Pulsar System: A Rare Laboratory for Relativistic Gravity and Plasma Physics
Authors: Lyne A. G. , Burgay M. , Kramer M. , Possenti A. , Manchester R.N. , Camilo F. , McLaughlin M. A. , Lorimer D. R. , D'Amico N. , Joshi B. C. , Reynolds J. , Freire P. C. C.
Published: January 2004

The clocklike properties of pulsars moving in the gravitational fields of their unseen neutron-star companions have allowed unique tests of general relativity and provided evidence for gravitational radiation. We report here the detection of the 2.8-second pulsar J0737–3039B as the companion to the 23-millisecond pulsar J0737–3039A in a highly relativistic double neutron star system, allowing unprecedented tests of fundamental gravitational physics. We observed a short eclipse of J0737–3039A by J0737–3039B and orbital modulation of the flux density and the pulse shape of J0737–3039B, probably because of the influence of J0737–3039A's energy flux on its magnetosphere. These effects will allow us to probe magneto-ionic properties of a pulsar magnetosphere.
The Membrane-Proximal Tyrosine-Based Sorting Signal of Human Immunodeficiency Virus Type 1 gp41 Is Required for Optimal Viral Infectivity
Authors: Day John R. , Münk Carsten , Guatelli John C.
Published: January 2004

The membrane-proximal tyrosine-based sorting motif in the cytoplasmic domain of the human immunodeficiency virus type 1 Env glycoprotein is important for endocytosis from the plasma membrane, basolateral targeting of viral budding in polarized epithelial cells, and polarized budding from a localized region of the lymphocyte plasma membrane. To study the role of the Env sorting motif (Y712XXL) in infectivity, the incorporation of Env into virions, and viral entry, we disrupted the motif with a tyrosine-to-alanine substitution. To investigate the relationship between the Env sorting motif and the enhancement of infectivity by Nef, the EnvY712A substitution was made in both Nef-positive and Nef-negative backgrounds. In spreading infections, including those using primary lymphocytes, the growth of the Y712A mutant was as impaired as Nef-negative virus, and the EnvY712A/Δ-Nef combination mutant was almost completely defective. In single-round infections using CD4-positive HeLa cells, the EnvY712A mutation impaired infectivity, and Nef retained the ability to enhance the infectivity in the context of EnvY712A. EnvY712 and Nef were required for the optimal infectivity of virions produced from either HEK293T or MT4 cells, but these sequences were required for the optimal incorporation of Env only when virions were produced from MT4 cells. Despite the wild-type levels of Env in viruses produced from 293T cells, the entry of the EnvY712A and Δ-Nef mutants into target cells was impaired. We conclude that the membrane-proximal tyrosine-based sorting motif of gp41 Env is, like Nef, important for optimal viral infectivity and, in the case of MT4 T cells, virion incorporation of Env. Nef does not require the Y712XXL motif to enhance viral infectivity. The finding that EnvY712 and Nef each affect the efficiency of viral entry independently of the Env content of virions suggests that both viral proteins are involved in trafficking events that influence morphogenesis to produce maximally fusogenic virus.
Simian Immunodeficiency Virus Promoter Exchange Results in a Highly Attenuated Strain That Protects against Uncloned Challenge Virus
Authors: Blancou Philippe , Chenciner Nicole , Fang Raphaël Ho Tsong , Monceaux Valérie , Cumont Marie-Christine , Guétard Denise , Hurtrel Bruno , Wain-Hobson Simon
Published: January 2004

Among the many simian immunodeficiency virus (SIV) immunogens, only live attenuated viral vaccines have afforded strong protection to a natural pathogenic isolate. Since the promoter is crucial to the tempo of viral replication in general, it was reasoned that promoter exchange might confer a novel means of attenuating SIV. The core enhancer and promoter sequences of the SIV macaque 239nefstop strain (NF-κB/Sp1 region from −114 bp to mRNA start) have been exchanged for those of the human cytomegalovirus immediate-early promoter (CMV-IE; from −525 bp to mRNA start). During culture of the resulting virus, referred to as SIVmegalo, on CEMx174 or rhesus macaque peripheral blood mononuclear cells, deletions arose in distal regions of the CMV-IE sequences that stabilized after 1 or 2 months of culture. However, when the undeleted form of SIVmegalo was inoculated into rhesus macaques, animals showed highly controlled viremia during primary and persistent infection. Compared to parental virus infection in macaques, primary viremia was reduced by >1,000-fold to undetectable levels, with little sign of an increase of cycling cells in lymph nodes, CD4
+
depletion, or altered T-cell activation markers in peripheral blood. Moreover, in contrast to wild-type infection in most infected animals, the nef stop mutation did not revert to the wild-type codon, indicating yet again that replication was dramatically curtailed. Despite such drastic attenuation, antibody titers and enzyme-linked immunospot reactivity to SIV peptides, although slower to appear, were comparable to those seen in a parental virus infection. When animals were challenged intravenously at 4 or 6 months with the uncloned pathogenic SIVmac251 strain, viremia was curtailed by ∼1,000-fold at peak height without any sign of hyperactivation in CD4
+
- or CD8
+
-T-cell compartment or increase in lymph node cell cycling. To date, there has been a general inverse correlation between attenuation and protection; however, these findings show that promoter exchange constitutes a novel means to highly attenuate SIV while retaining the capacity to protect against challenge virus.
Novel Insect Picorna-Like Virus Identified in the Brains of Aggressive Worker Honeybees
Authors: Fujiyuki Tomoko , Takeuchi Hideaki , Ono Masato , Ohka Seii , Sasaki Tetsuhiko , Nomoto Akio , Kubo Takeo
Published: January 2004

To identify candidate genes involved in the aggressive behavior of worker honeybees, we used the differential display method to search for RNAs exclusively detected in the brains of aggressive workers that had attacked a hornet. We identified a novel, 10,152-nucleotide RNA, termed
Kakugo
RNA.
Kakugo
RNA encodes a protein of 2,893 amino acid residues that shares structural features and sequence similarities with various picorna-like virus polyproteins, especially those from sacbrood virus, which infects honeybees. The Kakugo protein contains several domains that correspond to the virion protein, helicase, protease, and RNA-dependent RNA polymerase domains of various picorna-like virus polyproteins. When the worker bee tissue lysate was subjected to sucrose density gradient centrifugation,
Kakugo
RNA, except for the material at the bottom, was separated into two major peaks. One of the peaks corresponded to the position of
Kakugo
mRNA, and the other corresponded to the position of the poliovirus virion. These results suggest that the
Kakugo
RNA exists as an mRNA-like free RNA and virion RNA in the honeybee. Furthermore, injection of the lysate supernatant from the attacker heads into the heads of noninfected bees resulted in a marked increase in
Kakugo
RNA. These results demonstrate that
Kakugo
RNA is a plus-strand RNA of a novel picorna-like virus and that the brains of aggressive workers are infected by this novel virus.
Kakugo
RNA was detected in aggressive workers but not in nurse bees or foragers. In aggressive workers,
Kakugo
RNA was detected in the brain but not in the thorax or abdomen, indicating a close relation between viral infection in the brain and aggressive worker behaviors.
Nuclear Localization but Not PML Protein Is Required for Incorporation of the Papillomavirus Minor Capsid Protein L2 into Virus-Like Particles
Authors: Becker Katrin A. , Florin Luise , Sapp Cornelia , Maul Gerd G. , Sapp Martin
Published: January 2004

Recent reports suggest that nuclear domain(s) 10 (ND10) is the site of papillomavirus morphogenesis. The viral genome replicates in or close to ND10. In addition, the minor capsid protein, L2, accumulates in these subnuclear structures and recruits the major capsid protein, L1. We have now used cell lines deficient for promyelocytic leukemia (PML) protein, the main structural component of ND10, to study the role of this nuclear protein for L2 incorporation into virus-like particles (VLPs). L2 expressed in PML protein knockout (PML
−/−
) cells accumulated in nuclear dots, which resemble L2 aggregates forming at ND10 in PML protein-containing cells. These L2 assemblies also attracted L1 and the transcriptional repressor Daxx, suggesting that they are functional in the absence of PML protein. In addition, L2-containing VLPs assembled in PML
−/−
cells. In order to analyze whether incorporation of L2 into VLPs requires any specific subcellular localization, an L1 mutant defective for nuclear transport and L2 mutants deficient in nuclear translocation and/or ND10 localization were constructed. Using this approach, we identified two independent L2 domains interacting with L1. Mutant L2 proteins not accumulating in ND10 were incorporated into VLPs. Mutant L1 protein, which assembled into VLPs in the cytoplasm, did not incorporate L2 defective for nuclear translocation. The same mutant L2 protein, which passively diffuses into the nucleus, is incorporated into wild-type L1-VLPs in the nucleus. Our data demonstrate that the incorporation of L2 into VLPs requires nuclear but not ND10 localization.
Bunyamwera Bunyavirus RNA Synthesis Requires Cooperation of 3′- and 5′-Terminal Sequences
Authors: Barr John N. , Wertz Gail W.
Published: January 2004

Bunyamwera virus
(BUNV) is the prototype of both the
Orthobunyavirus
genus and the
Bunyaviridae
family of segmented negative-sense RNA viruses. The tripartite BUNV genome consists of small (S), medium (M), and large (L) segments that are each transcribed to yield a single mRNA and are replicated to generate an antigenome that acts as a template for synthesis of further genomic strands. As for all negative-sense RNA viruses, the 3′- and 5′-terminal nontranslated regions (NTRs) of the BUNV S, M, and L segments exhibit nucleotide complementarity and, except for one conserved U-G pairing, this complementarity extends for 15, 18, and 19 nucleotides, respectively. We investigated whether the complementarity of 3′ and 5′ NTRs reflected a functional requirement for terminal cooperation to promote BUNV RNA synthesis or, alternatively, was a consequence of genomic and antigenomic NTRs having similar functions requiring sequence conservation. We show that cooperation between 3′- and 5′-NTR sequences is required for BUNV RNA synthesis, and our results suggest that this cooperation is due to nucleotide complementarity allowing 3′ and 5′ NTRs to associate through base-pairing interactions. To examine the importance of complementarity in promoting BUNV RNA synthesis, we utilized a competitive replication assay able to examine the replication ability of all possible combinations of interacting nucleotides within a defined region of BUNV 3′ and 5′ NTRs. We show here that maximal RNA replication was signaled when sequences exhibiting perfect complementarity within 3′ and 5′ NTRs were selected.
Specific Histone Tail Modification and Not DNA Methylation Is a Determinant of Herpes Simplex Virus Type 1 Latent Gene Expression
Authors: Kubat Nicole J. , Tran Robert K. , McAnany Peterjon , Bloom David C.
Published: January 2004

During herpes simplex virus type 1 (HSV-1) latency, gene expression is tightly repressed except for the latency-associated transcript (LAT). The mechanistic basis for this repression is unknown, but its global nature suggests regulation by an epigenetic mechanism such as DNA methylation. Previous work demonstrated that latent HSV-1 genomes are not extensively methylated, but these studies lacked the resolution to examine methylation of individual CpGs that could repress transcription from individual promoters during latency. To address this point, we employed established models to predict genomic regions with the highest probability of being methylated and, using bisulfite sequencing, analyzed the methylation profiles of these regions. We found no significant methylation of latent DNA isolated from mouse dorsal root ganglia in any of the regions examined, including the ICP4 and LAT promoters. This analysis indicates that methylation is unlikely to play a major role in regulating HSV-1 latent gene expression. Subsequently we focused on differential histone modification as another epigenetic mechanism that could regulate latent transcription. Chromatin immunoprecipitation analysis of the latent HSV-1 DNA repeat regions demonstrated that a portion of the LAT region is associated with histone H3 acetylated at lysines 9 and 14, consistent with a euchromatic and nonrepressed structure. In contrast, the chromatin associated with the HSV-1 DNA polymerase gene located in the unique long segment was not enriched in H3 acetylated at lysines 9 and 14, suggesting a transcriptionally inactive structure. These data suggest that histone composition may be a major regulatory determinant of HSV latency.
Effects of an Epitope-Specific CD8+T-Cell Response on Murine Coronavirus Central Nervous System Disease: Protection from Virus Replication and Antigen Spread and Selection of Epitope Escape Mutants
Authors: Chua Ming Ming , MacNamara Katherine C. , San Mateo Lani , Shen Hao , Weiss Susan R.
Published: January 2004

Both CD4+and CD8+T cells are required for clearance of the murine coronavirus mouse hepatitis virus (MHV) during acute infection. We investigated the effects of an epitope-specific CD8+T-cell response on acute infection of MHV, strain A59, in the murine CNS. Mice with CD8+T cells specific for gp33-41 (an H-2Db-restricted CD8+T-cell epitope derived from lymphocytic choriomeningitis glycoprotein) were infected with a recombinant MHV-A59, also expressing gp33-41, as a fusion protein with enhanced green fluorescent protein (EGFP). By 5 days postinfection, these mice showed significantly (approximately 20-fold) lower titers of infectious virus in the brain compared to control mice. Furthermore mice with gp33-41-specific CD8+cells exhibited much reduced levels of viral antigen in the brain as measured by immunohistochemistry using an antibody directed against viral nucleocapsid. More than 90% of the viruses recovered from brain lysates of such protected mice, at 5 days postinfection, had lost the ability to express EGFP and had deletions in their genomes encompassing EGFP and gp33-41. In addition, genomes of viruses from about half the plaques that retained the EGFP gene had mutations within the gp33-41 epitope. On the other hand, gp33-41-specific cells failed to protect perforin-deficient mice from infection by the recombinant MHV expressing gp33, indicating that perforin-mediated mechanisms were needed. Virus recovered from perforin-deficient mice did not exhibit loss of EGFP expression and the gp33-41 epitope. These observations suggest that the cytotoxic T-cell response to gp33-41 exerts a strong immune pressure that quickly selects epitope escape mutants to gp33-41.
T-Cell Subsets That Harbor Human Immunodeficiency Virus (HIV) In Vivo: Implications for HIV Pathogenesis
Authors: Brenchley Jason M. , Hill Brenna J. , Ambrozak David R. , Price David A. , Guenaga Francisco J. , Casazza Joseph P. , Kuruppu Janaki , Yazdani Javaidia , Migueles Stephen A. , Connors Mark , Roederer Mario , Douek Daniel C. , Koup Richard A.
Published: January 2004

Identification of T-cell subsets that are infected in vivo is essential to understanding the pathogenesis of human immunodeficiency virus (HIV) disease; however, this goal has been beset with technical challenges. Here, we used polychromatic flow cytometry to sort multiple T-cell subsets to 99.8% purity, followed by quantitative PCR to quantify HIVgagDNA directly ex vivo. We show that resting memory CD4+T cells are the predominantly infected cells but that terminally differentiated memory CD4+T cells contain 10-fold fewer copies of HIV DNA. Memory CD8+T cells can also be infected upon upregulation of CD4; however, this is infrequent and HIV-specific CD8+T cells are not infected preferentially. Naïve CD4+T-cell infection is rare and principally confined to those peripheral T cells that have proliferated. Furthermore, the virus is essentially absent from naïve CD8+T cells, suggesting that the thymus is not a major source of HIV-infected T cells in the periphery. These data illuminate the underlying mechanisms that distort T-cell homeostasis in HIV infection.
The Immediate-Early 63 Protein of Varicella-Zoster Virus: Analysis of Functional Domains Required for Replication In Vitro and for T-Cell and Skin Tropism in the SCIDhu Model In Vivo
Authors: Baiker Armin , Bagowski Christoph , Ito Hideki , Sommer Marvin , Zerboni Leigh , Fabel Klaus , Hay John , Ruyechan William , Arvin Ann M.
Published: January 2004

The immediate-early 63-kDa (IE63) protein of varicella-zoster virus (VZV) is a phosphoprotein encoded by open reading frame (ORF) ORF63/ORF70. To identify functional domains, 22 ORF63 mutations were evaluated for effects on IE63 binding to the major VZV transactivator, IE62, and on IE63 phosphorylation and nuclear localization in transient transfections, and after insertion into the viral genome with VZV cosmids. The IE62 binding site was mapped to IE63 amino acids 55 to 67, with R59/L60 being critical residues. Alanine substitutions within the IE63 center region showed that S165, S173, and S185 were phosphorylated by cellular kinases. Four mutations that changed two putative nuclear localization signal (NLS) sequences altered IE63 distribution to a cytoplasmic/nuclear pattern. Only three of 22 mutations in ORF63 were compatible with recovery of infectious VZV from our cosmids, but infectivity was restored by inserting intact ORF63 into each mutated cosmid. The viable IE63 mutants had a single alanine substitution, altering T171, S181, or S185. These mutants, rOKA/ORF63rev[T171], rOKA/ORF63rev[S181], and rOKA/ORF63rev[S185], produced less infectious virus and had a decreased plaque phenotype in vitro. ORF47 kinase protein and glycoprotein E (gE) synthesis was reduced, indicating that IE63 contributed to optimal expression of early and late gene products. The three IE63 mutants replicated in skin xenografts in the SCIDhu mouse model, but virulence was markedly attenuated. In contrast, infectivity in T-cell xenografts was not altered. Comparative analysis suggested that IE63 resembled the herpes simplex virus type 1 U
S
1.5 protein, which is expressed colinearly with ICP22 (U
S
1). In summary, most mutations of ORF63 made with our VZV cosmid system were lethal for infectivity. The few IE63 changes that were tolerated resulted in VZV mutants with an impaired capacity to replicate in vitro. However, the IE63 mutants were attenuated in skin but not T cells in vivo, indicating that the contribution of the IE63 tegument/regulatory protein to VZV pathogenesis depends upon the differentiated human cell type which is targeted for infection within the intact tissue microenvironment.
Rapid Production of Neutralizing Antibody Leads to Transient Hepadnavirus Infection
Authors: Zhang Yong-Yuan , Summers Jesse
Published: January 2004

Hepatitis B virus (HBV) frequently causes transient infections in adults but chronic infections in infants. The basis of these age-related outcomes is not known. Infection of ducks with duck hepatitis B virus (DHBV) displays a similar dependence of outcome on the age of the host at the time of infection. In this study we compared the infection of ducks at 3 days and 3 weeks of age. We found that the efficiency of infection of hepatocytes by virus in the inoculum was similar between the two age groups but that spread of the infection throughout the liver was severely inhibited in the 3-week-old-old ducks, while a rapid spread of the infection was observed in 3-day-old ducklings. Inhibition of virus spread was accompanied by the appearance in the serum of virus neutralizing activity, as assayed by blocking of infection of primary hepatocyte cultures. Neutralizing activity appeared as early as 1 or 2 days postinfection and increased during the next 2 weeks. Depletion of immunoglobulins from serum eliminated the neutralizing activity. The specific depletion of IgM indicated that IgM appeared as the dominant fraction of neutralizing antibody in the first 2 days postinfection, but declined from day 3 on while IgG antibody rose. We conclude that excess neutralizing antibody arising rapidly in birds inoculated at 3 weeks of age but not in newly hatched ducks prevented secondary cycles of infection, resulting in a limited infection in the liver and contributing to the eventual transient outcome of the infection.
Human Cytomegalovirus Elicits a Coordinated Cellular Antiviral Response via Envelope Glycoprotein B
Authors: Boehme Karl W. , Singh Jasbir , Perry Stuart T. , Compton Teresa
Published: January 2004

Previous studies have shown that human cytomegalovirus (CMV) is a potent elicitor of interferon-stimulated gene (ISG) expression. Induction of the interferon pathway does not require replication-competent virus, and envelope glycoprotein B (gB) from CMV is a viral structural component that can directly induce transcription of ISGs. Here we extend these earlier findings by defining the consequences of inducing the interferon pathway. We found that cells respond to CMV or soluble gB by establishing a functional antiviral state within cell types critical in CMV biology, such as fibroblasts and endothelial cells. We have also discovered new insights into the mechanism by which the pathway is initiated. Interferon regulatory factor 3 (IRF3), a key transcriptional regulator of cellular interferon responses, is activated by CMV virions and soluble gB. Thus, IRF3 becomes activated via “outside-in” signal transduction events. This is a novel mechanism of activation of this key transcription factor by viruses. In comparison to soluble gB (gB1-750), which comprises the entire ectodomain of gB, a truncation mutant encompassing only the amino-terminal region of gB (gB1-460) was markedly less effective at inducing antiviral responses. This indicates that the region of gB from residues 461 to 750 is important for initiation of the antiviral response. In addition, CMV and gB establish an antiviral state in alpha/beta interferon null cells, illustrating that primary induction of ISGs by CMV and gB is sufficient to establish the antiviral response and that interferon secretion is not necessary for the antiviral effect. Taken together, our findings reveal that CMV initiates a coordinated antiviral response through contact between gB and an as-yet-unidentified cell surface receptor(s).
Borna Disease Virus Multiplication in Mouse Organotypic Slice Cultures Is Site-Specifically Inhibited by Gamma Interferon but Not by Interleukin-12
Authors: Friedl Gregor , Hofer Markus , Auber Bernd , Sauder Christian , Hausmann Jürgen , Staeheli Peter , Pagenstecher Axel
Published: January 2004

Borna disease virus (BDV) induces a nonpurulent CD4- and CD8-T-cell-dependent meningoencephalitis in susceptible animals. Upon intracerebral infection, BDV replicates in the mouse central nervous system (CNS), but only a few mouse strains develop neurological disorder. The antiviral T cells appear to suppress BDV replication by a noncytolytic mechanism. Since BDV does not replicate in standard mouse cell cultures, the putative role of gamma interferon (IFN-γ) in virus control could not be tested experimentally. Here, we report that mouse organotypic slice cultures can be used to elucidate the complex interactions of BDV, the CNS, and the immune system. We show that BDV replicated in various cell types of mouse cerebellar slice cultures in vitro. In infected slice cultures, a moderate upregulation of the chemokine genes CCL5 and CXCL10 was observed, while expression of various neural genes as well as other chemokine and cytokine genes was not altered. IFN-γ inhibited the multiplication of BDV in cerebellar and hippocampal slice cultures in a dose-dependent manner. However, while complete suppression of BDV was observed in cerebellar slice cultures, inhibition was incomplete in hippocampal slice cultures. Kinetic studies indicated that IFN-γ protects noninfected cells from infection rather than clearing the virus from infected cells. These results demonstrate that BDV can replicate in cultured neural cells of the mouse if organ integrity is well preserved. They further show that IFN-γ is a powerful inhibitor of BDV in the absence of blood-borne leukocytes in mouse cerebellar slice cultures.
Transduction of Bone-Marrow-Derived Mesenchymal Stem Cells by Using Lentivirus Vectors Pseudotyped with Modified RD114 Envelope Glycoproteins
Authors: Zhang Xian-Yang , La Russa Vincent F. , Reiser Jakob
Published: January 2004

Bone-marrow-derived mesenchymal stem cells (MSCs) have attracted considerable attention as tools for the systemic delivery of therapeutic proteins in vivo, and the ability to efficiently transfer genes of interest into such cells would create a number of therapeutic opportunities. We have designed and tested a series of human immunodeficiency virus type 1 (HIV-1)-based vectors and vectors based on the oncogenic murine stem cell virus to deliver and express transgenes in human MSCs. These vectors were pseudotyped with either the vesicular stomatitis virus G (VSV-G) glycoprotein (GP) or the feline endogenous virus RD114 envelope GP. Transduction efficiencies and transgene expression levels in MSCs were analyzed by quantitative flow cytometry and quantitative real-time PCR. While transduction efficiencies with virus particles pseudotyped with the VSV-G GP were found to be high, RD114 pseudotypes revealed transduction efficiencies that were 1 to 2 orders of magnitude below those observed with VSV-G pseudotypes. However, chimeric RD114 GPs, with the transmembrane and extracellular domains fused to the cytoplasmic domain derived from the amphotropic Moloney murine leukemia virus 4070A GP, revealed about 15-fold higher titers relative to the unmodified RD114 GP. The transduction efficiencies in human MSCs of HIV-1-based vectors pseudotyped with the chimeric RD114 GP were similar to those obtained with HIV-1 vectors pseudotyped with the VSV-G GP. Our results also indicate that RD114 pseudotypes were less toxic than VSV-G pseudotypes in human MSC progenitor assays. Taken together, these results suggest that lentivirus pseudotypes bearing alternative Env GPs provide efficient tools for ex vivo modification of human MSCs.