Epstein-Barr virus protein EBNA-LP engages YY1 through leucine-rich motifs to promote naïve B cell transformation

Epstein-Barr Virus (EBV) is associated with numerous cancers including B cell lymphomas. In vitro, EBV transforms primary B cells into immortalized Lymphoblastoid Cell Lines (LCLs) which serves as a model to study the role of viral proteins in EBV malignancies. EBV induced cellular transformation is driven by viral proteins including EBV-Nuclear Antigens (EBNAs). EBNA-LP is important for the transformation of naïve but not memory B cells. While EBNA-LP was thought to promote gene activation by EBNA2, EBNA-LP Knock Out (LPKO) virus-infected cells express EBNA2-activated genes efficiently. Therefore, a gap in knowledge exists as to what roles EBNA-LP plays in naïve B cell transformation. We developed a trans-complementation assay wherein transfection with wild-type EBNA-LP rescues the transformation of peripheral blood- and cord blood-derived naïve B cells by LPKO virus. Despite EBNA-LP phosphorylation sites being important in EBNA2 co-activation; neither phospho-mutant nor phospho-mimetic EBNA-LP was defective in rescuing naïve B cell outgrowth. However, we identified conserved leucine-rich motifs in EBNA-LP that were required for transformation of adult naïve and cord blood B cells. Because cellular PPAR-γ coactivator (PGC) proteins use leucine-rich motifs to engage transcription factors including YY1, a key regulator of DNA looping and metabolism, we examined the role of EBNA-LP in engaging cellular transcription factors. We found a significant overlap between EBNA-LP and YY1 in ChIP-Seq data and confirmed their biochemical association in LCLs by endogenous co-immunoprecipitation. Moreover, we found that the EBNA-LP leucine-rich motifs were required for YY1 interaction in LCLs. Finally, we used Cas9 to knockout YY1 in primary total B cells and naïve B cells prior to EBV infection and found YY1 to be essential for EBV-mediated transformation. We propose that EBNA-LP engages YY1 through conserved leucine-rich motifs to promote EBV transformation of naïve B cells.

Textbook outcome following oesophagectomy for cancer: international cohort study

Background

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

Methods

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

Results

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter ‘no major postoperative complication’ had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P < 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P < 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

Conclusion

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Textbook outcome following oesophagectomy for cancer: international cohort study

BACKGROUND

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

METHODS

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

RESULTS

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter 'no major postoperative complication' had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P < 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P < 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

CONCLUSION

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND

The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting.

METHODS

Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups.

RESULTS

Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005).

CONCLUSION

Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery.

Localized structures on librational and rotational travelling waves in the sine-Gordon equation

We derive exact solutions to the sine-Gordon equation describing localized structures on the background of librational and rotational travelling waves. In the case of librational waves, the exact solution represents a localized spike in space-time coordinates (a rogue wave) that decays to the periodic background algebraically fast. In the case of rotational waves, the exact solution represents a kink propagating on the periodic background and decaying algebraically in the transverse direction to its propagation. These solutions model the universal patterns in the dynamics of fluxon condensates in the semi-classical limit. The different dynamics are related to modulational instability of the librational waves and modulational stability of the rotational waves.

Information flows and topic modeling in corporate governance

Purpose

Multiple disciplines such as finance, management and economics have contributed to governance research over time. However, the full intellectual structure of the governance “field” including the exchange of knowledge across disciplines and the large variety of governance topics remains to be uncovered. To appreciate the breadth of corporate governance research, it is necessary to understand the disciplinary sources from which the research stems. This manuscript focuses on the interdisciplinary underpinnings of corporate governance research.

Design/methodology/approach

This paper employs bibliometric analysis to trace the evolution of corporate governance using articles included in the ISI Web of Science database between 1990 and 2015. Journals included in these categories encompass a full range of business disciplines and provide evidence of the multi-disciplinary nature of corporate governance. It also uncovers the topics treated by disciplines under the governance umbrella using a machine learning method called latent Dirichtlet allocation (LDA).

Findings

Corporate governance research deals with a number of strategy-related topics. Unlike strategy topics that reside in a single discipline, corporate governance crosses disciplinary boundaries and includes contributions from accounting, finance, economics, law and management. Our analysis shows that over 80% of corporate governance articles come from outside the field of management. Our LDA solution indicates that the major topics in governance research include corporate governance theory, control of family firms, executive compensation and audit committees.

Originality/value

The results illustrate that corporate governance is far more interdisciplinary than previously thought. This is an important insight for corporate governance academics and may lead to collaborative research. More importantly, this research illustrates the usefulness of LDA for investigating interdisciplinary fields. This method is easily transferable to other interdisciplinary fields and it provides a powerful alternative to existing bibliometric methods. We suggest a number of topic areas within library and information science where this method may be applied, including collection development, support for interdisciplinary faculty and basic research into emerging interdisciplinary areas.

Essential role of inverted repeat in Epstein-Barr virus IR-1 in B cell transformation; geographical variation of the viral genome

Many regions of the Epstein–Barr virus (EBV) genome, repeated and unique sequences, contribute to the geographical variation observed between strains. Here we use a large alignment of curated EBV genome sequences to identify major sites of variation in the genome of type 1 EBV strains; the CAO deletion in latent membrane protein 1 (LMP1) is the most frequent major indel present in the unique regions of EBV strains from various parts of the world. Principal component analysis was used to identify patterns of sequence variation and nucleotide positions in the sequences that can distinguish EBV from some different geographical regions. Viral genome sequence variation also affects interpretation of genetic content; known genes, origins of replication and gene expression control regions explain most of the viral genome but there are still a few sections of unknown function. One of these EBV genome regions contains a large inverted repeat sequence (invR) within the IR-1 major internal repeat array. We deleted this invR sequence and showed that this abolished the ability of the virus to transform human B cells into lymphoblastoid cell lines.

This article is part of the theme issue ‘Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses’.

Rogue waves on the double-periodic background in the focusing nonlinear Schrödinger equation

The double-periodic solutions of the focusing nonlinear Schrödinger equation have been previously obtained by the method of separation of variables. We construct these solutions by using an algebraic method with two eigenvalues. Furthermore, we characterize the Lax spectrum for the double-periodic solutions and analyze rogue waves arising on the background of such solutions. Magnification of the rogue waves is studied numerically.

Persistent KSHV Infection Increases EBV-Associated Tumor Formation In Vivo via Enhanced EBV Lytic Gene Expression

The human tumor viruses Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) establish persistent infections in B cells. KSHV is linked to primary effusion lymphoma (PEL), and 90% of PELs also contain EBV. Studies on persistent KSHV infection in vivo and the role of EBV co-infection in PEL development have been hampered by the absence of small animal models. We developed mice reconstituted with human immune system components as a model for KSHV infection and find that EBV/KSHV dual infection enhanced KSHV persistence and tumorigenesis. Dual-infected cells displayed a plasma cell-like gene expression pattern similar to PELs. KSHV persisted in EBV-transformed B cells and was associated with lytic EBV gene expression, resulting in increased tumor formation. Evidence of elevated lytic EBV replication was also found in EBV/KSHV dually infected lymphoproliferative disorders in humans. Our data suggest that KSHV augments EBV-associated tumorigenesis via stimulation of lytic EBV replication.

Epstein-Barr virus nuclear antigen EBNA-LP is essential for transforming naïve B cells, and facilitates recruitment of transcription factors to the viral genome

The Epstein-Barr virus (EBV) nuclear antigen leader protein (EBNA-LP) is the first viral latency-associated protein produced after EBV infection of resting B cells. Its role in B cell transformation is poorly defined, but it has been reported to enhance gene activation by the EBV protein EBNA2 in vitro. We generated EBNA-LP knockout (LPKO) EBVs containing a STOP codon within each repeat unit of internal repeat 1 (IR1). EBNA-LP-mutant EBVs established lymphoblastoid cell lines (LCLs) from adult B cells at reduced efficiency, but not from umbilical cord B cells, which died approximately two weeks after infection. Adult B cells only established EBNA-LP-null LCLs with a memory (CD27+) phenotype. Quantitative PCR analysis of virus gene expression after infection identified both an altered ratio of the EBNA genes, and a dramatic reduction in transcript levels of both EBNA2-regulated virus genes (LMP1 and LMP2) and the EBNA2-independent EBER genes in the first 2 weeks. By 30 days post infection, LPKO transcription was the same as wild-type EBV. In contrast, EBNA2-regulated cellular genes were induced efficiently by LPKO viruses. Chromatin immunoprecipitation revealed that EBNA2 and the host transcription factors EBF1 and RBPJ were delayed in their recruitment to all viral latency promoters tested, whereas these same factors were recruited efficiently to several host genes, which exhibited increased EBNA2 recruitment. We conclude that EBNA-LP does not simply co-operate with EBNA2 in activating gene transcription, but rather facilitates the recruitment of several transcription factors to the viral genome, to enable transcription of virus latency genes. Additionally, our findings suggest that EBNA-LP is essential for the survival of EBV-infected naïve B cells.

Epstein-Barr virus (EBV) infects almost everyone. Once infected, people harbor the virus for life, shedding it in saliva. Infection of children is asymptomatic, but a first infection during adolescence or adulthood can cause glandular fever (infectious mononucleosis). EBV is also implicated in several different cancers. EBV infection of B cells (antibody-producing immune cells) can drive them to replicate almost indefinitely (‘transformation’), generating cell lines. We have investigated the role of an EBV protein (EBNA-LP) which is thought to support gene activation by the essential virus protein EBNA2. We have made an EBV in which the EBNA-LP gene has been disrupted. This virus (LPKO) shows several properties. 1. It is reduced in its ability to transform B cells; 2. ‘Naïve’ B cells (those whose antibodies have not adapted to fight infections) die two weeks after LPKO infection; 3. Some virus genes fail to turn on immediately after LPKO infection. 4. Binding of EBNA2 and various cellular factors to these genes is delayed. 5. EBNA-LP does not affect EBNA2-targeted cellular genes in the same way. This shows that EBNA-LP is more important in naïve B cells, and that it helps to turn on virus genes, but not cell genes.

Heterogeneity of the Epstein-Barr Virus (EBV) Major Internal Repeat Reveals Evolutionary Mechanisms of EBV and a Functional Defect in the Prototype EBV Strain B95-8

Epstein-Barr virus (EBV) is a ubiquitous pathogen of humans that can cause several types of lymphoma and carcinoma. Like other herpesviruses, EBV has diversified through both coevolution with its host and genetic exchange between virus strains. Sequence analysis of the EBV genome is unusually challenging because of the large number and lengths of repeat regions within the virus. Here we describe the sequence assembly and analysis of the large internal repeat 1 of EBV (IR1; also known as the BamW repeats) for more than 70 strains. The diversity of the latency protein EBV nuclear antigen leader protein (EBNA-LP) resides predominantly within the exons downstream of IR1. The integrity of the putative BWRF1 open reading frame (ORF) is retained in over 80% of strains, and deletions truncating IR1 always spare BWRF1. Conserved regions include the IR1 latency promoter (Wp) and one zone upstream of and two within BWRF1. IR1 is heterogeneous in 70% of strains, and this heterogeneity arises from sequence exchange between strains as well as from spontaneous mutation, with interstrain recombination being more common in tumor-derived viruses. This genetic exchange often incorporates regions of <1 kb, and allelic gene conversion changes the frequency of small regions within the repeat but not close to the flanks. These observations suggest that IR1-and, by extension, EBV-diversifies through both recombination and breakpoint repair, while concerted evolution of IR1 is driven by gene conversion of small regions. Finally, the prototype EBV strain B95-8 contains four nonconsensus variants within a single IR1 repeat unit, including a stop codon in the EBNA-LP gene. Repairing IR1 improves EBNA-LP levels and the quality of transformation by the B95-8 bacterial artificial chromosome (BAC).IMPORTANCE Epstein-Barr virus (EBV) infects the majority of the world population but causes illness in only a small minority of people. Nevertheless, over 1% of cancers worldwide are attributable to EBV. Recent sequencing projects investigating virus diversity to see if different strains have different disease impacts have excluded regions of repeating sequence, as they are more technically challenging. Here we analyze the sequence of the largest repeat in EBV (IR1). We first characterized the variations in protein sequences encoded across IR1. In studying variations within the repeat of each strain, we identified a mutation in the main laboratory strain of EBV that impairs virus function, and we suggest that tumor-associated viruses may be more likely to contain DNA mixed from two strains. The patterns of this mixing suggest that sequences can spread between strains (and also within the repeat) by copying sequence from another strain (or repeat unit) to repair DNA damage.

EBV epigenetically suppresses the B cell-to-plasma cell differentiation pathway while establishing long-term latency

Mature human B cells infected by Epstein-Barr virus (EBV) become activated, grow, and proliferate. If the cells are infected ex vivo, they are transformed into continuously proliferating lymphoblastoid cell lines (LCLs) that carry EBV DNA as extra-chromosomal episomes, express 9 latency-associated EBV proteins, and phenotypically resemble antigen-activated B-blasts. In vivo similar B-blasts can differentiate to become memory B cells (MBC), in which EBV persistence is established. Three related latency-associated viral proteins EBNA3A, EBNA3B, and EBNA3C are transcription factors that regulate a multitude of cellular genes. EBNA3B is not necessary to establish LCLs, but EBNA3A and EBNA3C are required to sustain proliferation, in part, by repressing the expression of tumour suppressor genes. Here we show, using EBV-recombinants in which both EBNA3A and EBNA3C can be conditionally inactivated or using virus completely lacking the EBNA3 gene locus, that-after a phase of rapid proliferation-infected primary B cells express elevated levels of factors associated with plasma cell (PC) differentiation. These include the cyclin-dependent kinase inhibitor (CDKI) p18INK4c, the master transcriptional regulator of PC differentiation B lymphocyte-induced maturation protein-1 (BLIMP-1), and the cell surface antigens CD38 and CD138/Syndecan-1. Chromatin immunoprecipitation sequencing (ChIP-seq) and chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) indicate that in LCLs inhibition of CDKN2C (p18INK4c) and PRDM1 (BLIMP-1) transcription results from direct binding of EBNA3A and EBNA3C to regulatory elements at these loci, producing stable reprogramming. Consistent with the binding of EBNA3A and/or EBNA3C leading to irreversible epigenetic changes, cells become committed to a B-blast fate <12 days post-infection and are unable to de-repress p18INK4c or BLIMP-1-in either newly infected cells or conditional LCLs-by inactivating EBNA3A and EBNA3C. In vitro, about 20 days after infection with EBV lacking functional EBNA3A and EBNA3C, cells develop a PC-like phenotype. Together, these data suggest that EBNA3A and EBNA3C have evolved to prevent differentiation to PCs after infection by EBV, thus favouring long-term latency in MBC and asymptomatic persistence.

Genome diversity of Epstein-Barr virus from multiple tumor types and normal infection

Epstein-Barr virus (EBV) infects most of the world's population and is causally associated with several human cancers, but little is known about how EBV genetic variation might influence infection or EBV-associated disease. There are currently no published wild-type EBV genome sequences from a healthy individual and very few genomes from EBV-associated diseases. We have sequenced 71 geographically distinct EBV strains from cell lines, multiple types of primary tumor, and blood samples and the first EBV genome from the saliva of a healthy carrier. We show that the established genome map of EBV accurately represents all strains sequenced, but novel deletions are present in a few isolates. We have increased the number of type 2 EBV genomes sequenced from one to 12 and establish that the type 1/type 2 classification is a major feature of EBV genome variation, defined almost exclusively by variation of EBNA2 and EBNA3 genes, but geographic variation is also present. Single nucleotide polymorphism (SNP) density varies substantially across all known open reading frames and is highest in latency-associated genes. Some T-cell epitope sequences in EBNA3 genes show extensive variation across strains, and we identify codons under positive selection, both important considerations for the development of vaccines and T-cell therapy. We also provide new evidence for recombination between strains, which provides a further mechanism for the generation of diversity. Our results provide the first global view of EBV sequence variation and demonstrate an effective method for sequencing large numbers of genomes to further understand the genetics of EBV infection.

IMPORTANCE

Most people in the world are infected by Epstein-Barr virus (EBV), and it causes several human diseases, which occur at very different rates in different parts of the world and are linked to host immune system variation. Natural variation in EBV DNA sequence may be important for normal infection and for causing disease. Here we used rapid, cost-effective sequencing to determine 71 new EBV sequences from different sample types and locations worldwide. We showed geographic variation in EBV genomes and identified the most variable parts of the genome. We identified protein sequences that seem to have been selected by the host immune system and detected variability in known immune epitopes. This gives the first overview of EBV genome variation, important for designing vaccines and immune therapy for EBV, and provides techniques to investigate relationships between viral sequence variation and EBV-associated diseases.

Safe handling of cytotoxics: guideline recommendations

BACKGROUND

This evidence-based practice guideline was developed to update and address new issues in the handling of cytotoxics, including the use of oral cytotoxics; the selection and use of personal protective equipment; and treatment in diverse settings, including the home setting.

METHODS

The guideline was developed primarily from an adaptation and endorsement of an existing guideline and from three systematic reviews. Before publication, the guideline underwent a series of peer and external reviews to gather feedback. All comments were addressed, and the guideline was amended when required. The guideline applies to health care workers who could come into contact with cytotoxic drugs at any point in the medication circuit. The intended users are hospital administrators, educators, and managers; occupational health and safety services; and pharmacy and health care workers.

RESULTS

The recommendations represent a reasonable and practical set of procedures that the intended users of this guideline should implement to minimize opportunities for accidental exposure. They are not limited to just the point of care; they cover the entire chain of cytotoxics handling from the time such agents enter the institution until they leave in the patient or as waste.

CONCLUSIONS

Reducing the likelihood of accidental exposure to cytotoxic agents within the medication circuit is the main objective of this evidenced-based guideline. The recommendations differ slightly from earlier guidelines because of the availability of new evidence.

Employment and Market Innovation in Chinese Business Group Affiliated Firms: The Role of Group Control Systems

Prior research has suggested a number of potential benefits to firm membership in business groups. These benefits include availability of capital and other resources not readily accessible in an open market, the facilitation of entrepreneurship, plus information and risk sharing advantages. We suggest that another important benefit is the assistance of group control systems in helping the firm to manage conflicting pressures in the institutional environment and facilitate coevolution of these conflicting pressures. To empirically demonstrate the relevance of this viewpoint, we examine the case of China where business groups facilitate institutional transition, actively balancing market pressures to increase levels of innovativeness in firms with institutional pressures emanating from the government to maintain high employment levels. Using data from a broad sample of more than 1,000 Chinese affiliate firms in more than 200 business groups, we find that government policy, ownership and managerial mindset influence the political goal of maintaining high employment levels, while interdependence among group affiliate firms is related to lower employment levels. However, while government ownership and the government managerial mindset were negatively related to market innovation activities, group financial and cultural control systems positively affected the tendency of affiliate firms to focus on market innovation.

Hyperhomocysteinemia is detrimental to pregnancy in mice and is associated with preterm birth

Elevated levels of homocysteine produce detrimental effects in humans but its role in preterm birth is not known. Here we used a mouse model of hyperhomocysteinemia to examine the relevance of homocysteine to preterm birth. The mouse carries a heterozygous deletion of cystathionine β-synthase (Cbs(+/-)). Gestational period was monitored in wild type and Cbs(+/-) female mice. Mouse uterine and placental tissues, human primary trophoblast cells, and human myometrial and placental cell lines were used to determine the influence of homocysteine on expression of specific genes in vitro. The activity of BKCa channel in the myometrial cell line was monitored using the patch-clamp technique. We found that hyperhomocysteinemia had detrimental effects on pregnancy and induced preterm birth in mice. Homocysteine increased the expression of oxytocin receptor and Cox-2 as well as PGE2 production in uterus and placenta, and initiated premature uterine contraction. A Cox-2 inhibitor reversed these effects. Gpr109a, a receptor for niacin, induced Cox-2 in uterus. Homocysteine upregulated GPR109A and suppressed BKCa channel activity in human myometrial cells. Deletion of Gpr109a in Cbs(+/-) mice reversed premature birth. We conclude that hyperhomocysteinemia causes preterm birth in mice through upregulation of the Gpr109a/Cox-2/PGE2 axis and that pharmacological blockade of Gpr109a may have potential in prevention of preterm birth.

Induction of p16(INK4a) is the major barrier to proliferation when Epstein-Barr virus (EBV) transforms primary B cells into lymphoblastoid cell lines

To explore the role of p16^INK4a as an intrinsic barrier to B cell transformation by EBV, we transformed primary B cells from an individual homozygous for a deletion in the CDKN2A locus encoding p16^INK4a and p14^ARF. Using recombinant EBV-BAC viruses expressing conditional EBNA3C (3CHT), we developed a system that allows inactivation of EBNA3C in lymphoblastoid cell lines (LCLs) lacking active p16^INK4a protein but expressing a functional 14^ARF-fusion protein (p14/p16). The INK4a locus is epigenetically repressed by EBNA3C – in cooperation with EBNA3A – despite the absence of functional p16^INK4a. Although inactivation of EBNA3C in LCLs from normal B cells leads to an increase in p16^INK4a and growth arrest, EBNA3C inactivation in the p16^INK4a-null LCLs has no impact on the rate of proliferation, establishing that the repression of INK4a is a major function of EBNA3C in EBV-driven LCL proliferation. This conditional LCL system allowed us to use microarray analysis to identify and confirm genes regulated specifically by EBNA3C, independently of proliferation changes modulated by the p16^INK4a-Rb-E2F axis. Infections of normal primary B cells with recombinant EBV-BAC virus from which EBNA3C is deleted or with 3CHT EBV in the absence of activating ligand 4-hydroxytamoxifen, revealed that EBNA3C is necessary to overcome an EBV-driven increase in p16^INK4a expression and concomitant block to proliferation 2–4 weeks post-infection. If cells are p16^INK4a-null, functional EBNA3C is dispensable for the outgrowth of LCLs.

Epstein-Barr virus (EBV) is a causative agent of several types of B cell lymphoma. In human B cells, EBV reduces protein levels of at least two tumour suppressors that would otherwise be activated in response to over-expressed oncogenes. These proteins are BIM, which induces cell death and p16^INK4a, which prevents cell proliferation. Repression of both is via epigenetic methylation of histones and is dependent on expression of both EBNA3A and EBNA3C – two EBV proteins required for the transformation of normal B cells into lymphoblastoid cell lines (LCLs). In this report we have used EBV with a conditionally active EBNA3C – active only in the presence of 4-hydroxytamoxifen – together with B cells from an individual carrying a homozygous deletion of p16^INK4a to confirm that regulation of p16^INK4a expression is a major function of EBNA3C and demonstrate that if B cells lack p16^INK4a, then EBNA3C is no longer required for EBV-driven proliferation of LCLs. Furthermore we show that early after the infection of normal B cells, EBV induces p16^INK4a accumulation that – if unchecked by EBNA3C (and EBNA3A) – prevents LCL outgrowth. Formal proof that p16^INK4a is the main target of EBNA3C comes with the production of p16-null LCLs that have never expressed functional EBNA3C.

BIM promoter directly targeted by EBNA3C in polycomb-mediated repression by EBV

Detailed analyses of the chromatin around the BIM promoter has revealed that latent Epstein–Barr virus (EBV) triggers the recruitment of polycomb repressive complex 2 (PRC2) core subunits and the trimethylation of histone H3 lysine 27 (H3K27me3) at this locus. The recruitment is absolutely dependent on nuclear proteins EBNA3A and EBNA3C; what is more, epitope-tagged EBNA3C could be shown bound near the transcription start site (TSS). EBV induces no consistent changes in the steady-state expression of PRC2 components, but lentivirus delivery of shRNAs against PRC2 and PRC1 subunits disrupted EBV repression of BIM. The activation mark H3K4me3 is largely unaltered at this locus irrespective of H3K27me3 status, suggesting the establishment of a ‘bivalent’ chromatin domain. Consistent with the ‘poised’ nature of these domains, RNA polymerase II (Pol II) occupancy was not altered by EBV at the BIM TSS, but analysis of phospho-serine 5 on Pol II indicated that EBNA3A and EBNA3C together inhibit initiation of BIM transcripts. B cell lines carrying EBV encoding a conditional EBNA3C-oestrogen receptor-fusion revealed that this epigenetic repression of BIM was reversible, but took more than 3 weeks from when EBNA3C was inactivated.

EBNA3B-deficient EBV promotes B cell lymphomagenesis in humanized mice and is found in human tumors

Epstein-Barr virus (EBV) persistently infects more than 90% of the human population and is etiologically linked to several B cell malignancies, including Burkitt lymphoma (BL), Hodgkin lymphoma (HL), and diffuse large B cell lymphoma (DLBCL). Despite its growth transforming properties, most immune-competent individuals control EBV infection throughout their lives. EBV encodes various oncogenes, and of the 6 latency-associated EBV-encoded nuclear antigens, only EBNA3B is completely dispensable for B cell transformation in vitro. Here, we report that infection with EBV lacking EBNA3B leads to aggressive, immune-evading monomorphic DLBCL-like tumors in NOD/SCID/γc-/- mice with reconstituted human immune system components. Infection with EBNA3B-knockout EBV (EBNA3BKO) induced expansion of EBV-specific T cells that failed to infiltrate the tumors. EBNA3BKO-infected B cells expanded more rapidly and secreted less T cell-chemoattractant CXCL10, reducing T cell recruitment in vitro and T cell-mediated killing in vivo. B cell lines from 2 EBV-positive human lymphomas encoding truncated EBNA3B exhibited gene expression profiles and phenotypic characteristics similar to those of tumor-derived lines from the humanized mice, including reduced CXCL10 secretion. Screening EBV-positive DLBCL, HL, and BL human samples identified additional EBNA3B mutations. Thus, EBNA3B is a virus-encoded tumor suppressor whose inactivation promotes immune evasion and virus-driven lymphomagenesis.

Latent Epstein-Barr virus can inhibit apoptosis in B cells by blocking the induction of NOXA expression

Latent Epstein-Barr virus (EBV) has been shown to protect Burkitt's lymphoma-derived B cells from apoptosis induced by agents that cause damage to DNA, in the context of mutant p53. This protection requires expression of the latency-associated nuclear proteins EBNA3A and EBNA3C and correlates with their ability to cooperate in the repression of the gene encoding the pro-apoptotic, BH3-only protein BIM. Here we confirm that latent EBV in B cells also inhibits apoptosis induced by two other agents--ionomycin and staurosporine--and show that these act by a distinct pathway that involves a p53-independent increase in expression of another pro-apoptotic, BH3-only protein, NOXA. Analyses employing a variety of B cells infected with naturally occurring EBV or B95.8 EBV-BAC recombinant mutants indicated that the block to NOXA induction does not depend on the well-characterized viral latency-associated genes (EBNAs 1, 2, 3A, 3B, 3C, the LMPs or the EBERs) or expression of BIM. Regulation of NOXA was shown to be at least partly at the level of mRNA and the requirement for NOXA to induce cell death in this context was demonstrated by NOXA-specific shRNA-mediated depletion experiments. Although recombinant EBV with a deletion removing the BHRF1 locus--that encodes the BCL2-homologue BHRF1 and three microRNAs--partially abrogates protection against ionomycin and staurosporine, the deletion has no effect on the EBV-mediated block to NOXA accumulation.

An ATM/Chk2-mediated DNA damage-responsive signaling pathway suppresses Epstein-Barr virus transformation of primary human B cells

Epstein-Barr virus (EBV), an oncogenic herpesvirus that causes human malignancies, infects and immortalizes primary human B cells in vitro into indefinitely proliferating lymphoblastoid cell lines, which represent a model for EBV-induced tumorigenesis. The immortalization efficiency is very low suggesting that an innate tumor suppressor mechanism is operative. We identify the DNA damage response (DDR) as a major component of the underlying tumor suppressor mechanism. EBV-induced DDR activation was not due to lytic viral replication nor did the DDR marks co-localize with latent episomes. Rather, a transient period of EBV-induced hyper-proliferation correlated with DDR activation. Inhibition of the DDR kinases ATM and Chk2 markedly increased transformation efficiency of primary B cells. Further, the viral latent oncoproteins EBNA3C was required to attenuate the EBV-induced DNA damage response We propose that heightened oncogenic activity in early cell divisions activates a growth-suppressive DDR which is attenuated by viral latency products to induce cell immortalization.

Extensive co-operation between the Epstein-Barr virus EBNA3 proteins in the manipulation of host gene expression and epigenetic chromatin modification

Epstein-Barr virus (EBV) is able to drive the transformation of B-cells, resulting in the generation of lymphoblastoid cell lines (LCLs) in vitro. EBV nuclear proteins EBNA3A and EBNA3C are necessary for efficient transformation, while EBNA3B is dispensable. We describe a transcriptome analysis of BL31 cells infected with a series of EBNA3-knockout EBVs, including one deleted for all three EBNA3 genes. Using Affymetrix Exon 1.0 ST microarrays analysed with the MMBGX algorithm, we have identified over 1000 genes whose regulation by EBV requires one of the EBNA3s. Remarkably, a third of the genes identified require more than one EBNA3 for their regulation, predominantly EBNA3C co-operating with either EBNA3B, EBNA3A or both. The microarray was validated by real-time PCR, while ChIP analysis of a selection of co-operatively repressed promoters indicates a role for polycomb group complexes. Targets include genes involved in apoptosis, cell migration and B-cell differentiation, and show a highly significant but subtle alteration in genes involved in mitosis. In order to assess the relevance of the BL31 system to LCLs, we analysed the transcriptome of a set of EBNA3B knockout (3BKO) LCLs. Around a third of the genes whose expression level in LCLs was altered in the absence of EBNA3B were also altered in 3BKO-BL31 cell lines.

Among these are TERT and TCL1A, implying that EBV-induced changes in the expression of these genes are not required for B-cell transformation. We also identify 26 genes that require both EBNA3A and EBNA3B for their regulation in LCLs. Together, this shows the complexity of the interaction between EBV and its host, whereby multiple EBNA3 proteins co-operate to modulate the behaviour of the host cell.

The Cardiovascular Research Network: a new paradigm for cardiovascular quality and outcomes research

BACKGROUND

A clear need exists for a more systematic understanding of the epidemiology, diagnosis, and management of cardiovascular diseases. More robust data are also needed on how well clinical trials are translated into contemporary community practice and the associated resource use, costs, and outcomes.

METHODS AND RESULTS

The National Heart, Lung, and Blood Institute recently established the Cardiovascular Research Network, which represents a new paradigm to evaluate the epidemiology, quality of care, and outcomes of cardiovascular disease and to conduct future clinical trials using a community-based model. The network includes 15 geographically distributed health plans with dedicated research centers, National Heart, Lung, and Blood Institute representatives, and an external collaboration and advisory committee. Cardiovascular research network sites bring complementary content and methodological expertise and a diverse population of approximately 11 million individuals treated through various health care delivery models. Each site's rich electronic databases (eg, sociodemographic characteristics, inpatient and outpatient diagnoses and procedures, pharmacy, laboratory, and cost data) are being mapped to create a standardized virtual data warehouse to facilitate rapid and efficient large-scale research studies. Initial projects focus on (1) hypertension recognition and management, (2) quality and outcomes of warfarin therapy, and (3) use, outcomes, and costs of implantable cardioverter defibrillators.

CONCLUSIONS

The Cardiovascular Research Network represents a new paradigm in the approach to cardiovascular quality of care and outcomes research among community-based populations. Its unique ability to characterize longitudinally large, diverse populations will yield novel insights into contemporary disease and risk factor surveillance, management, outcomes, and costs. The Cardiovascular Research Network aims to become the national research partner of choice for efforts to improve the prevention, diagnosis, treatment, and outcomes of cardiovascular diseases.

Epigenetic repression of p16(INK4A) by latent Epstein-Barr virus requires the interaction of EBNA3A and EBNA3C with CtBP

As an inhibitor of cyclin-dependent kinases, p16^INK4A is an important tumour suppressor and inducer of cellular senescence that is often inactivated during the development of cancer by promoter DNA methylation. Using newly established lymphoblastoid cell lines (LCLs) expressing a conditional EBNA3C from recombinant EBV, we demonstrate that EBNA3C inactivation initiates chromatin remodelling that resets the epigenetic status of p16^INK4A to permit transcriptional activation: the polycomb-associated repressive H3K27me3 histone modification is substantially reduced, while the activation-related mark H3K4me3 is modestly increased. Activation of EBNA3C reverses the distribution of these epigenetic marks, represses p16^INK4A transcription and allows proliferation. LCLs lacking EBNA3A express relatively high levels of p16^INK4A and have a similar pattern of histone modifications on p16^INK4A as produced by the inactivation of EBNA3C. Since binding to the co-repressor of transcription CtBP has been linked to the oncogenic activity of EBNA3A and EBNA3C, we established LCLs with recombinant viruses encoding EBNA3A- and/or EBNA3C-mutants that no longer bind CtBP. These novel LCLs have revealed that the chromatin remodelling and epigenetic repression of p16^INK4A requires the interaction of both EBNA3A and EBNA3C with CtBP. The repression of p16^INK4A by latent EBV will not only overcome senescence in infected B cells, but may also pave the way for p16^INK4A DNA methylation during B cell lymphomagenesis.

We previously showed that two Epstein-Barr virus latency-associated proteins—EBNA3A and EBNA3C—contribute to enhanced B cell survival by inhibiting the expression of the death-inducing protein BIM. This repression involves remodelling of the BIM gene promoter by polycomb proteins and DNA methylation within an unusually large CpG-island that flanks the transcription initiation site. Here we show that the same two proteins, EBNA3A and EBNA3C, functionally cooperate in the polycomb-mediated chromatin remodelling of another tumour suppressor gene, p16^INK4A, that encodes a cyclin-dependent kinase inhibitor capable of blocking cell proliferation. Both EBV proteins can bind the highly conserved co-repressor of transcription CtBP, and these interactions appear to be required for the efficient repression of p16^INK4A. Thus by utilising the polycomb system to induce the heritable repression of two major tumour suppressor genes—one that induces cell death (BIM) and one that induces growth arrest (p16^INK4A)—EBV profoundly alters latently infected B cells and their progeny, making them significantly more prone to malignant transformation.

Statin use does not prevent recurrent adenomatous polyp formation in a VA population

PURPOSE

To evaluate whether statin use was associated with recurrent adenomatous polyps.

METHODS

We conducted a retrospective cohort study. We used electronic health records to evaluate veterans who underwent polypectomy between January 1, 1999 and December 31, 2001 and surveillance colonoscopy by December 2006. We obtained data on pathology, demographics, body mass index, comorbidity, habits, family history, and medications. We used multivariate proportional hazards regression models to analyze data.

RESULTS

We evaluated 197 eligible patients from among 821 who underwent colonoscopy during this period; their mean (SD) age was 63.1 (8.8) years, 192 (98%) were men, and 80 (41%) non-Hispanic white. Surveillance colonoscopy was performed after a mean (SD) 1207 (452) days and 108 (55%) patients had recurrent adenomas. During follow-up, 88 (47%) of patients received statins, but use was not protective against recurrent adenomas (hazard ratio = 1.36, 95% CI 0.35-8.27). Only number of polyps at initial colonoscopy predicted recurrent adenomas (1.98, 95% CI 1.27-3.08).

CONCLUSIONS

The use of statins was not protective against the recurrence of adenomatous polyps.

Association between migraine, anxiety and depression

Logistic regression was used to evaluate the relationship between self-reported medical diagnosis of migraine, self-reported depressive symptomology (RDS) and self-reported anxious symptomology (RAS) in the National Health Interview Survey ( n = 30 852). Semipartial squared correlations evaluated the population-level variability between RDS, RAS and migraine impairment. Migraine prevalence was 15.2% (overall), 20.5% (women) and 9.4% (men). Migraine risk was higher in participants with RAS [odds ratio (OR) 2.30, 95% confidence interval (CI) 2.09, 2.52), with RDS (OR 2.23, 95% CI 1.93, 2.58), who smoked (OR 1.19, 95% CI 1.09, 1.30), or who consulted a mental health provider (OR 1.45, 95% CI 1.27, 1.65). Although migraine risk was increased in both women (OR 1.93) and men (OR 2.42) with RAS ( P < 0.001), men with RAS had a higher migraine risk than did women with RAS ( P < 0.001). Only 7% of the variability in migraine impairment (population level) was predicted by variability in RDS and/or RAS.

Epstein-barr virus latency in B cells leads to epigenetic repression and CpG methylation of the tumour suppressor gene Bim

In human B cells infected with Epstein-Barr virus (EBV), latency-associated virus gene products inhibit expression of the pro-apoptotic Bcl-2-family member Bim and enhance cell survival. This involves the activities of the EBV nuclear proteins EBNA3A and EBNA3C and appears to be predominantly directed at regulating Bim mRNA synthesis, although post-transcriptional regulation of Bim has been reported. Here we show that protein and RNA stability make little or no contribution to the EBV-associated repression of Bim in latently infected B cells. However, treatment of cells with inhibitors of histone deacetylase (HDAC) and DNA methyltransferase (DNMT) enzymes indicated that epigenetic mechanisms are involved in the down-regulation of Bim. This was initially confirmed by chromatin immunoprecipitation analysis of histone acetylation levels on the Bim promoter. Consistent with this, methylation-specific PCR (MSP) and bisulphite sequencing of regions within the large CpG island located at the 5′ end of Bim revealed significant methylation of CpG dinucleotides in all EBV-positive, but not EBV-negative B cells examined. Genomic DNA samples exhibiting methylation of the Bim promoter included extracts from a series of explanted EBV-positive Burkitt's lymphoma (BL) biopsies. Subsequent analyses of the histone modification H3K27-Me3 (trimethylation of histone H3 lysine 27) and CpG methylation at loci throughout the Bim promoter suggest that in EBV-positive B cells repression of Bim is initially associated with this repressive epigenetic histone mark gradually followed by DNA methylation at CpG dinucleotides. We conclude that latent EBV initiates a chain of events that leads to epigenetic repression of the tumour suppressor gene Bim in infected B cells and their progeny. This reprogramming of B cells could have important implications for our understanding of EBV persistence and the pathogenesis of EBV-associated disease, in particular BL.

Bim is a cellular inducer of programmed cell death (pcd), so the level of Bim is a critical regulator of lymphocyte survival and reduced expression enhances lymphomagenesis in mice and humans. Regulation of Bim is uniquely important in the pathogenesis of Burkitt's lymphoma (BL), since in this human childhood cancer the Myc gene is deregulated by chromosomal translocation and Myc can induce pcd via Bim. Latent EBV represses Bim expression, and here we have discovered that this involves mechanisms that reprogramme B cells and their progeny. EBV does not significantly alter Bim protein or RNA stability, but relief of EBV-mediated repression by specific inhibitors suggested it involves modifications to chromatin. Consistent with this, reduced histone acetylation and increased levels of DNA methylation on the Bim promoter were found after latent EBV infection. Further analysis suggested that the DNA methylation is preceded by repression mediated via a polycomb protein repressive complex targeting the Bim gene. By initiating the heritable suppression of Bim, EBV increases the likelihood of B lymphomagenesis in general and BL in particular. This reprogramming of B cells by EBV may also play a role in the development of other chronic disorders such as autoimmune disease and suggests a general mechanism that could contribute to the pathogenesis associated with other microorganisms.

Health information technology will shift the medical care paradigm

The current paradigm of medical care depends heavily on the autonomous and highly trained doctor to collect and process information necessary to care for each patient. This paradigm is challenged by the increasing requirements for knowledge by both patients and doctors; by the need to evaluate populations of patients inside and outside one's practice; by consistently unmet quality of care expectations; by the costliness of redundant, fragmented, and suboptimal care; and by a seemingly insurmountable demand for chronic disease care. Medical care refinements within the old paradigm may not solve these challenges, suggesting a shift to a new paradigm is needed. A new paradigm could be considerably more reliant on health information technology because that offers the best option for addressing our challenges and creating a foundation for future medical progress, although this process will be disruptive.

Osteoporosis management in prostate cancer patients treated with androgen deprivation therapy

BACKGROUND

The use of androgen deprivation therapy (ADT) for prostate cancer has increased substantially in recent years, exposing more men to potential treatment complications, including osteoporosis and fractures.

OBJECTIVE

To determine whether men treated with ADT for prostate cancer received osteoporosis screening, prevention, or treatment.

DESIGN

Cross-sectional observational study using a retrospective review of electronic medical records.

SUBJECTS

One hundred seventy-four patients with prostate cancer on ADT or status-post orchiectomy enrolled in primary care at the New Mexico Veterans Affairs Health Care System as of July 2005.

MEASUREMENTS

Patient demographics, tumor characteristics (Gleason score, stage, last PSA value, documented bone metastases), history of hip or vertebral fracture, osteoporosis risk factors (number of ADT shots, diabetes, smoking, heavy alcohol use or prescriptions for corticosteroids, thyroid hormone or dilantin). We defined recommended management as performing DXA scans or prescribing bisphosphonates, calcitonin, calcium or vitamin D.

RESULTS

Just 60 of 174 (34%) patients received recommended osteoporosis management based on DXA scans (13%) or treatment with oral or IV bisphosphonates (21%), calcitonin (1%), calcium (16%) or vitamin D (10%). On multivariate analysis, bone metastases, higher last PSA, and younger age at diagnosis were associated with recommended management, whereas Hispanic race/ethnicity was inversely associated.

CONCLUSIONS

Most men treated with ADT for prostate cancer did not receive osteoporosis screening, prevention or treatment. Evidence for advanced cancer though not risk factors for osteoporosis or fracture-was associated with receiving osteoporosis management. Further research is needed to identify optimal strategies for screening, prevention, and treatment in this population.

Two Epstein-Barr virus (EBV) oncoproteins cooperate to repress expression of the proapoptotic tumour-suppressor Bim: clues to the pathogenesis of Burkitt's lymphoma

Epstein-Barr virus (EBV) contributes to the development of several human cancers including the endemic form of Burkitt's lymphoma (BL). In culture, EBV induces the continuous proliferation of primary B cells as lymphoblastoid cell lines (LCLs) and if EBV-negative BL-derived cells are infected with EBV, latency-associated viral factors confer resistance to various inducers of apoptosis. Nuclear proteins EBNA3A and EBNA3C (but not EBNA3B) are necessary to establish LCLs and their expression may be involved in the resistance of BL cells to cytotoxic agents. We have therefore created recombinant EBVs from which each of the EBNA3 genes has been independently deleted, and revertant viruses in which the genes have been re-introduced into the viral genome. Infection of EBV-negative BL cells with this panel of EBVs and challenge with various cytotoxic drugs showed that EBNA3A and EBNA3C cooperate as the main determinants of both drug resistance and the downregulation of the proapoptotic Bcl-2-family member Bcl-2-interacting mediator of cell death (Bim). The regulation of Bim is predominantly at the level of RNA, with little evidence of post-translational Bim stabilization by EBV. In the absence of Bim, EBNA3A and EBNA3C appear to provide no survival advantage. The level of Bim is a critical regulator of B cell survival and reduced expression is a major determinant of lymphoproliferative disease in mice and humans; moreover, Bim is uniquely important in the pathogenesis of BL. By targeting this tumour-suppressor for repression, EBV significantly increases the likelihood of B lymphomagenesis in general, and BL in particular. Our results may also explain the selection pressure that gives rise to a subset of BL that retain expression of the EBNA3 proteins.

Mutagenesis of the herpesvirus saimiri terminal repeat region reveals important elements for virus production

Deletion of the terminal repeats (TR) from herpesvirus saimiri (HVS) renders it unable to produce infectious virus or generate plaques. However, a TR-deleted HVS bacterial artificial chromosome can form replication compartments. Complementation of this mutant shows that one copy of the TR, plus the right junction of the genome with the TR, is sufficient for efficient plaque formation and generation of infectious virus. Within the TR unit, the region around the cleavage site of the genome appears both necessary and sufficient for virus production. Analysis of episomes from productive cells indicates a propensity to amplify TR numbers during the lytic cycle.

Epstein–Barr virus origin of lytic replication mediates association of replicating episomes with promyelocytic leukaemia protein nuclear bodies and replication compartments

Epstein–Barr virus (EBV) establishes a latent persistence from which it can be reactivated to undergo lytic replication. Late lytic-cycle gene expression is linked to lytic DNA replication, as it is sensitive to the same inhibitors that block lytic replication, and it has recently been shown that the viral origin of lytic replication (ori lyt) is required in cis for late-gene expression. During the lytic cycle, the viral genome forms replication compartments, which are usually adjacent to promyelocytic leukaemia protein (PML) nuclear bodies. A tetracycline repressor DNA-binding domain–enhanced green fluorescent protein fusion was used to visualize replicating plasmids carrying a tetracycline operator sequence array. ori lyt mediated the production of plasmid replication compartments that were associated with PML nuclear bodies. Plasmids carrying ori lyt and EBV itself were visualized in the same cells and replicated in similar regions of the nucleus, further supporting the validity of the plasmids for studying late-gene regulation.

Effect of compost treatment of sewage sludge on nitrogen behavior in two soils

This work aims to evaluate the effects of compost treatment of digested sewage sludge on nitrogen behavior in two soils, a Spodosol and an Oxisol soil. Digested sewage sludge was composted with sawdust and woodchips, diluting the total nitrogen to one-fourth (dry mass basis) of its original value. Then, sludge and compost were added to the two soils on an equivalent dry weight basis to consider the risk of NO3- -N leaching. Compost treatment of sewage sludge has slowed down the release of mineral-N to half in the Spodosol and to one-third in Oxisol soil. As a result, NO3- -N concentrations in soils incubated with compost were less than half of the amounts found from soils incubated with digested sludge. Estimates were made of the maximum monthly nitrate to leach from the four combinations of soil and sludge treatment. Application of digested sludge, at a higher nitrogen application rate, resulted in a higher nitrate leaching potential than application of the compost product. Soil type also played an important role, with the Oxisol having slightly higher estimated leaching potential than the Spodosol. The higher nitrate release rate in the Oxisol is counterbalanced by its higher field capacity to lessen the expected difference between the two soils.

Open reading frame 73 is required for herpesvirus saimiri A11-S4 episomal persistence

Herpesvirus saimiri (HVS) establishes a latent infection in which the viral genome persists as a non-integrated episome. Analysis has shown that only open reading frames (ORFs) 71-73 are transcribed in an in vitro model of HVS latency. ORF73 also colocalizes with HVS genomic DNA on host mitotic chromosomes and maintains the stability of HVS terminal-repeat-containing plasmids. However, it is not known whether ORF73 is the only HVS-encoded protein required for episomal maintenance. In this study, the elements required for episomal maintenance in the context of a full-length HVS genome were examined by mutational analysis. A recombinant virus, HVS-BAC delta71-73, lacking the latency-associated genes was unable to persist in a dividing cell population. However, retrofitting an ORF73 expression cassette into the recombinant virus rescued episomal maintenance. This indicates that ORF73 is the key trans-acting factor for episomal persistence and efficient establishment of a latent infection.

Development of herpesvirus-based episomally maintained gene delivery vectors

Successful gene therapy aims to deliver and express therapeutic genes to cure or slow the progression of disease. However, a major obstacle in the application of gene therapy has been the development of the vectors used to deliver heterologous DNA to the cell or tissue of choice. A number of viral- and non-viral-based vector systems have undergone clinical trials with varying success. However, at present, no vector system possesses the full complement of properties that are generally believed necessary in an ideal gene delivery system. Therefore, alongside attempts to improve current gene delivery vectors, the identification and evaluation of new viral vectors is crucial for the long-term success of gene therapy. Herpesviruses are large DNA viruses which possess a number of advantages as gene delivery vectors. These relate to an ability to package large DNA insertions and establish lifelong latent infections in which the genomic material exists as a stable episome. This review aims to highlight the potential of herpesvirus vectors, in particular an alternative vector system based on herpesvirus saimiri (HVS). HVS is capable of infecting a range of human cell lines with high efficiencies, and the viral genome persists as high copy number, circular, non-integrated episomes which segregate to progeny following cell division. This allows the virus-based vector to stably transduce a dividing cell population and provide sustained transgene expression for an extended period of time both in vitro and in vivo. Moreover, the insertion of a bacterial artificial chromosome cassette into the HVS genome simplifies the incorporation of large amounts of heterologous DNA for gene delivery. These properties offer characteristics similar to an artificial chromosome combined with an efficient delivery system and merit its continual development as a possible gene delivery vector for the future.

Absence of human papillomavirus in esophageal carcinomas from southwestern Kenya

Esophageal squamous cell cancer is highly prevalent in south-western Kenya. The role of human papillomavirus (HPV) in esophageal cancers from this region was evaluated. Biopsies of 29 esophageal squamous cell cancers were assayed for HPV DNA sequences by reverse line blot polymerase chain reaction, using 27 HPV type-specific probes. Viral sequences were found in none of the specimens. These results suggest the HPV is unlikely to be an etiologic factor for esophageal squamous cell cancers in this region.

Functional delivery of large genomic DNA to human cells with a peptide-lipid vector

BACKGROUND

Nonviral gene transfer vectors have the potential to deliver much larger DNA constructs than current viral vectors but suffer from a low transfection efficiency. The LID vector, composed of Lipofectin (L), an integrin-targeting peptide (I) and DNA (D), is a highly efficient synthetic vector, both in vitro and in vivo, which may allow the transfer of genomic loci for gene therapy.

METHODS

Transfection efficiencies were quantitated using the green fluorescent protein (GFP) reporter. Expression of a large genomic locus (NBS1 [Nijmegen breakage syndrome], encoding nibrin) was assessed by immunofluorescence.

RESULTS

We report a systematic study of the parameters influencing delivery of BAC-based plasmids ranging in size from 12 to 242 kb using the LID vector. We showed 60% of cells were transfected with the smaller plasmids while plasmids up to 242 kb were consistently delivered to over 10% of cells. The number of transfected cells was related to number of plasmids in the transfection complex independent of plasmid size. Atomic force microscopy showed that LID particle size increased with plasmid size consistent with one plasmid molecule per particle. When LID vectors were used to deliver the NBS1 gene as a 143 kb construct to primary NBS cells, at least 57% of cells expressing GFP also expressed functional nibrin.

CONCLUSIONS

We show that LID vectors represent a promising tool for the transfer of complete genomic loci.

Pyocystis in patients on chronic dialysis. A potentially misdiagnosed syndrome

Pyocystis is an important complication of non-functioning urinary bladder, which often poses diagnostic difficulties. We present a case of pyocystis in a patient on chronic hemodialysis who was anuric for one year. The patient was initially diagnosed with diverticulitis. An abdominal C-T scan suggested the diagnosis of pyocystis, which was confirmed by bladder catheterization. The patient was treated with bladder drainage and a prolonged antibiotic course, followed by intermittent saline washing of the bladder.

Generation and precise modification of a herpesvirus saimiri bacterial artificial chromosome demonstrates that the terminal repeats are required for both virus production and episomal persistence

Herpesvirus saimiri (HVS) is the prototype gamma-2 herpesvirus, and shares considerable homology with the human gammaherpesviruses Kaposi's sarcoma-associated herpesvirus and Epstein–Barr virus. The generation of herpesvirus mutants is a key facet in the study of virus biology. The use of F-factor-based bacterial artificial chromosomes (BACs) to clone and modify the genomes of herpesviruses has enhanced the variety, precision and simplicity of mutant production. Here we describe the cloning of the genome of HVS non-transforming strain A11-S4 into a BAC. The cloning of the BAC elements disrupts open reading frame (ORF) 15 but the HVS-BAC can still replicate at levels similar to wild-type virus, and can persistently infect fibroblasts. The HVS-BAC was modified by RecA-mediated recombination initially to substitute reporter genes and also to delete the terminal repeats (TR). After deletion of the TR, the HVS-BAC fails to enter a productive virus lytic cycle, and cannot establish a persistent episomal infection when transfected into fibroblast cell lines. This shows that while ORF 15 is dispensable for virus function in vitro, the TR is required for both virus latency and lytic virus production. In addition, the HVS-BAC promises to be a valuable tool that can be used for the routine and precise production and analysis of viral mutants to further explore gammaherpesvirus biology.

Classification of the degree of obesity by body mass index or by deviation from ideal weight

BACKGROUND

The purpose of this study was to compare classifications of subjects as underweight, normal weight, or obese by body mass index (BMI) and the ratio of body weight to ideal weight (W/IW).

METHODS

We performed a theoretical comparison of the 2 indices. We compared classifications of the degree of obesity in 1839 women and 5914 men who were followed up in the primary care clinics of a United States federal hospital. Information was extracted from computerized records. Subjects were classified as underweight (BMI < 18.5 kg/m2, W/IW < 0.9), obese (BMI > or = 30.0 kg/m2, W/IW > or = 1.2), or normal weight (BMI, W/IW values between the cutoff values for underweight and obesity). W/IW values were computed assuming small, medium, and large skeletal frame for all. We compared the classifications of subjects as underweight, normal weight, or obese by BMI and W/IW. We used Cohen's kappa ratio to evaluate the agreement between these classifications.

RESULTS

Theoretically, the cutoff values of BMI and W/IW for underweight and obesity are not in agreement. Patient data revealed substantial differences in the classifications of subjects as underweight, normal weight, or obese. Kappa ratios ranged between 0.18 (poor agreement) and 0.71 (reasonable, but not high degree of agreement). In general, kappa ratios were higher when assuming large or medium skeletal frame versus small frame.

CONCLUSIONS

There are substantial discrepancies in classifying the subjects of a population as underweight, normal weight, or obese by BMI or W/IW. These discrepancies may cause confusion when 2 or more indices are used simultaneously to classify the degree of obesity.

Oxidative activation of acylguanidine prodrugs: intestinal presystemic activation in rats limits absorption and can be inhibited by co-administration of ketoconazole

1. The disposition of acyl prodrugs was studied to improve the delivery of a guanidine-containing parent compound with poor membrane permeability and poor absorption. 2. The prodrugs were evaluated in vitro and in vivo for conversion to drug. Prodrugs were evaluated for hydrolytic or oxidative bioactivation in intestinal homogenate and rat liver S9 or microsomes. The disposition of the prodrugs in vivo was monitored in bile duct-cannulated rats. 3. Compounds with n-alkylacyl groups were efficiently bioactivated, but were hydrolysed before absorption. 4. Hydrolytic bioactivation could be blocked in vitro by branching in the alkyl chain. These compounds showed modest improvements in absorption, despite favourable permeability. Experiments with liver microsomes demonstrated efficient NADPH-dependent oxidative bioactivation, which was proposed to occur through a CYP-mediated side chain oxidation followed by cyclization and release of parent compound. Ketoconazole co-administration yielded approximately a twofold increase in absorption. 5. The hydrolytically stable prodrugs were successful in increasing absorption of parent drug and were efficiently bioactivated, but they did not yield increased systemic levels of drug.

Sorption and degradation characteristics of phosmet in two contrasting Australian soils

The organophosphate insecticide phosmet [phosphorodithioic acid, s-((1,3-dihydro-1,3-dioxo-2H-isoindol-2yl)methyl), o,o-dimethyl ester] is used to control red-legged earth mites (Halotydeus destructor), lucerne flea (Sminthurus viridis), and Oriental fruit moth (Cydia molesta) in horticulture and vegetable growing. This study was undertaken with two soils of contrasting properties to determine the extent to which sorption and degradation of the insecticide might influence its potential to leach from soil into receiving waters. Two soils were used: a highly organic, oxidic clay soil (Ferrosol) and a sandy soil low in organic matter (Podosol), sampled to 0.3 m depth. The extent of sorption and decomposition rate of a phosmet commercial formulation were measured in laboratory experiments. Sorption followed a Freundlich isotherm at all depths. The Freundlich coefficient K was significantly correlated (p = 0.005) with organic C content in the Podosol, and significantly correlated (p = 0.005) with organic C and clay content in the Ferrosol. K was highest (48.8 L kg-1) in the 0- to 0.05-m depth of the Ferrosol, but lowest (1.0 L kg-1) at this depth in the Podosol. Degradation followed first-order kinetics, with the phosmet half-life ranging from 14 h (0-0.05 m depth) to 187 h (0.2-0.3 m depth) in the Ferrosol. The half-life was much longer in the sandy Podosol, ranging from 462 to 866 h, and did not change significantly with depth. Soil organic C and to a lesser degree clay content influenced phosmet sorption and degradation, but the interaction was complex and possibly affected by co-solvents present in the commercial formulation.

Infectious delivery of 120-kilobase genomic DNA by an epstein-barr virus amplicon vector

It has been shown in a wide variety of contexts that persistent gene expression can best be obtained by using the genomic locus of a transgene. However, the size of most genomic loci precludes their use in current viral gene therapy vectors. Large transgene capacity and extrachromosomal persistence make Epstein-Barr virus (EBV) a promising vector to deliver genomic transgenes for gene therapy. We constructed an EBV amplicon vector that contains the EBV lytic origin of replication, the terminal repeats for viral packaging, and the EBV latent origin of replication for episomal persistence. This vector was able to deliver inserts of 60-123 kb to B-cell lines in culture in three steps. First, clonal packaging cells lines were generated that produce infectious amplicons at a titer of approximately 3-4x10(6) transducing units/ml after concentration. Second, we show infectious vector delivery to the Loukes B-cell line and three different EBV-immortalized lymphoblastoid cell lines. This infectious delivery system was 2000 times more efficient than transfection in B cells. Third, clonal cell lines from infection of Loukes contained persistent episomes of recircularized infectious vector. This first demonstration of infectious delivery of 120 kb of genomic DNA shows the potential of this high-capacity vector system.

Effect of posterior capsular repair on early dislocation in primary total hip replacement

Formal repair of the posterior capsule and short external rotator tendons has been described as a surgical approach to reduce the incidence of posterior dislocation after posterolateral surgical approach to primary total hip replacement. The purpose of the current study was to compare the incidence of early posterior dislocation (within the first 6 months after surgery) using a complete posterior capsulectomy versus a formal posterior capsular repair. In patients with a complete posterior capsulectomy, 52 of 1078 primary total hip replacements (4.8%) had an early posterior dislocation. In patients with posterior capsular repair, three of 437 primary total hip replacements (0.7%) had an early posterior dislocation. This difference was statistically significant. The only complication in the capsular repair group was an avulsion fracture of the greater trochanter in four of 437 total hip replacements (0.9%).