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1.
Proc Biol Sci ; 287(1919): 20192478, 2020 01 29.
Article in English | MEDLINE | ID: mdl-31964300

ABSTRACT

Evolutionary demography predicts that variation in reproductive timing stems from socio-ecologically contingent trade-offs between current and future reproduction. In contemporary high-income societies, the costs and benefits of current reproduction are likely to vary by socioeconomic status (SES). Two influential hypotheses, focusing on the parenthood 'wage penalty', and responses to local mortality have separately been proposed to influence the timing of parenthood. Economic costs of reproduction (i.e. income loss) are hypothesized to delay fertility, especially among high childhood SES individuals who experience greater opportunities to build capital through advantageous education and career opportunities. On the other hand, relatively low childhood SES individuals experience higher mortality risk, which may favour earlier reproduction. Here, we examine both hypotheses with a representative register-based, multigenerational dataset from contemporary Finland (N = 47 678). Consistent with each hypothesis, the predicted financial cost of early parenthood was smaller, and mortality among close kin was higher for individuals with lower childhood SES. Within the same dataset, lower predicted adulthood income and more kin deaths were also independently associated with earlier parenthood. Our results provide a robust demonstration of how economic costs and mortality relate to reproductive timing. We discuss the implications of our findings for demographic theory and public policy.


Subject(s)
Death , Reproduction , Social Class , Adult , Age Factors , Child , Demography , Finland , Humans , Income , Salaries and Fringe Benefits , Socioeconomic Factors
2.
Perfusion ; 32(2): 97-109, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27708000

ABSTRACT

Modified ultrafiltration (MUF) is a technique which is commonly used immediately post-cardiopulmonary bypass (CPB) for open heart surgery in children. There are many advantages of MUF, but there are also a number of less reported disadvantages. At our institution, after considering all of the available data, a decision was made to no longer perform MUF. The primary motivation being the simplified and miniaturized CPB circuit would reduce hemodilution, decrease our likelihood of reaching our transfusion trigger during CPB and, potentially, improve safety. This study reports the before and after data from this practice change. A total of 160 patients less than 8kg were studied over 38 months and divided into neonatal and pediatric cohorts. Parameters reported in this study include: demographics, hematocrit, blood product transfusion, hemostasis, hemodynamics and outcomes. Although retrospective, our analysis supports an advantage of preventing hemodilution (via circuit miniaturization) versus reversing hemodilution (via MUF) at our institution with the patient population we examined.


Subject(s)
Cardiopulmonary Bypass/methods , Heart Arrest, Induced/methods , Ultrafiltration/methods , Blood Transfusion , Cardiopulmonary Bypass/instrumentation , Equipment Design , Heart Arrest, Induced/instrumentation , Hematocrit , Hemodynamics , Hemostasis , Humans , Infant , Infant, Newborn , Retrospective Studies , Ultrafiltration/instrumentation
3.
Perfusion ; 32(4): 264-268, 2017 May.
Article in English | MEDLINE | ID: mdl-27856841

ABSTRACT

BACKGROUND: Current blood pumps used for cardiopulmonary bypass generally fall into two different pump design categories; non-occlusive centrifugal pumps and occlusive, positive-displacement roller pumps. The amount of foreign surface area of extracorporeal circuits correlates with post-operative morbidity due to systemic inflammation, leading to a push for technology that reduces the amount of foreign surfaces. Current roller pumps are bulky and the tubing forms an arc in the pumping chamber (raceway), positioning the inlet 360 degrees from the outlet, making it very difficult to place the pump closer to the patient and to efficiently reduce tubing length. These challenges put existing roller pumps at a disadvantage for use in a compact cardiopulmonary bypass circuit. Centrifugal blood pumps are easier to incorporate into miniature circuit designs. However, the prime volumes of current centrifugal pump designs are large, especially for pediatric extracorporeal circuits where the prime volumes are too great to be of clinical value. METHOD: We describe a preliminary report on a novel, occlusive, linear, single-helix, positive-displacement blood pump which allows for decreased prime volume and surface area of the extracorporeal circuit. This new experimental pump design was used to perfuse a 6 kilogram piglet with a pediatric cardiopulmonary bypass circuit for two hours of continuous use. Blood samples were obtained every thirty minutes and assayed for plasma free hemolysis generation. CONCLUSIONS: The results from this initial experiment showed low plasma free hemoglobin generation and encourages the authors to further develop this concept.


Subject(s)
Cardiopulmonary Bypass/instrumentation , Cardiopulmonary Bypass/methods , Heart-Assist Devices , Animals , Female , Hemolysis , Swine
4.
Nat Rev Immunol ; 1(1): 75-82, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11905817

ABSTRACT

In vitro, Epstein-Barr virus (EBV) will infect any resting B cell, driving it out of the resting state to become an activated proliferating lymphoblast. Paradoxically, EBV persists in vivo in a quiescent state in resting memory B cells that circulate in the peripheral blood. How does the virus get there, and with such specificity for the memory compartment? An explanation comes from the idea that two genes encoded by the virus--LMP1 and LMP2A--allow EBV to exploit the normal pathways of B-cell differentiation so that the EBV-infected B blast can become a resting memory cell.


Subject(s)
B-Lymphocytes/immunology , Herpesvirus 4, Human/immunology , Herpesvirus 4, Human/pathogenicity , CD40 Antigens/metabolism , Epstein-Barr Virus Infections/immunology , Genes, Viral , Herpesvirus 4, Human/genetics , Humans , Immunologic Memory , Lymphocyte Activation , Models, Immunological , Receptors, Antigen, B-Cell/metabolism , Signal Transduction/immunology , Viral Matrix Proteins/genetics , Viral Matrix Proteins/immunology
5.
Pediatr Res ; 74(4): 413-9, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23863853

ABSTRACT

BACKGROUND: The utility of procalcitonin (PCT) and C-reactive protein (CRP) as infectious biomarkers following infant cardiothoracic surgery is not well defined. METHODS: We designed a prospective cohort study to evaluate PCT and CRP after infant cardiothoracic surgery. PCT and CRP were drawn preoperatively and 24/72 h postoperation or daily in delayed sternal closure patients. Presence of infection within 10 d of surgery, vasoactive-inotropic scores at 24 and 72 h, and length of intubation, intensive care unit stay, and hospital stay were documented. RESULTS: PCT and CRP were elevated at 24 h. PCT then decreased while CRP increased in patients undergoing delayed sternal closure or cardiopulmonary bypass. In the delayed sternal closure group, PCT was significantly higher on postoperative days 2-5 in patients who ultimately developed infection. Higher PCT was independently associated with increased vasoactive-inotropic score at 72 h. CRP did not correlate with infection or postoperative support. CONCLUSION: PCT rises after cardiothoracic surgery in infants but decreases by 72 h while CRP remains elevated. Sternal closure may affect CRP but not PCT. PCT is independently associated with circulatory support requirements at 72 h postoperation and with development of infection. PCT may have greater utility as a biomarker in this population.


Subject(s)
Biomarkers/blood , C-Reactive Protein/metabolism , Calcitonin/blood , Cardiovascular Surgical Procedures/adverse effects , Postoperative Complications/blood , Protein Precursors/blood , Sepsis/blood , Analysis of Variance , Calcitonin Gene-Related Peptide , Cohort Studies , Humans , Infant , Infant, Newborn , Kinetics , Linear Models , Liver Function Tests , Prospective Studies , Statistics, Nonparametric , Time Factors
6.
J Extra Corpor Technol ; 45(2): 107-11, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23930379

ABSTRACT

UNLABELLED: The timing of blood product administration after cardiopulmonary bypass (CPB) may influence the amount of postoperative transfusion and chest tube output. We performed a retrospective study of a novel technique of administering blood products during modified ultrafiltration (MUF) in congenital cardiac surgery. A Control Group (CG; n = 55) received cryoprecipitate and platelets after modified ultrafiltration. The Treatment Group (TG; n = 59) received cryoprecipitate and platelets during MUF. Volumes of blood products transfused in the operating room, initial coagulation parameters in the cardiac intensive care unit, and first 24-hour chest tube output were recorded. Age (116 +/- 198 versus 84 +/- 91 days), weight (4.6 +/- 1.8 versus 4.5 +/- 1.4 kg), duration of bypass (121 +/- 50 versus 139 +/- 57 minutes), and Aristotle scoring (9.3 +/- 2.7 versus 9.1 +/- 3.1) were not significantly different when comparing the control and treatment groups, respectively. Intraoperative packed red blood cells (74.4 +/- 34.8 versus 79.3 +/- 58.0 mL/kg, p = .710), fresh-frozen plasma (58.3 +/- 27.1 versus 59.1 +/- 27.2 mL/kg, p = .849), cryoprecipitate (7.3 +/- 5.1 versus 8.6 +/- 5.9 mL/kg, p = .109), and platelet (19.0 +/- 14.6 versus 23.7 +/- 20.8 mL/kg, p = .176) administration were the same in the control and treatment groups, respectively. However, fibrinogen levels on arrival in the coronary intensive care unit were significantly higher (305 +/- 80 versus 255 +/- 40 mg/dL, p < .001) in the CG compared with the TG. Twenty-four-hour chest tube output was not significantly different but the CG (17.76 +/- 9.34 mL/kg/24 hours) was trending lower than the TG (19.52 +/- 10.94 mL/kg/24 hours, p = .357). In an attempt to minimize CPB-associated bleeding and transfusions, we changed our practice by adjusting the timing of blood product administration after patient separation from CPB. The goals of the change in practice were not measurably different in terms of shorter intraoperative times, fewer blood transfusions, or less chest tube output at our institution. KEYWORDS: congenital heart disease, modified ultrafiltration, cryoprecipitate, platelets, cardiopulmonary bypass.


Subject(s)
Cardiopulmonary Bypass/instrumentation , Factor VIII/administration & dosage , Fibrinogen/administration & dosage , Heart Defects, Congenital/nursing , Heart Defects, Congenital/surgery , Hemofiltration/instrumentation , Platelet Transfusion/instrumentation , Equipment Design , Equipment Failure Analysis , Female , Humans , Infant , Male
7.
Crit Care ; 16(4): R160, 2012 Aug 20.
Article in English | MEDLINE | ID: mdl-22906145

ABSTRACT

INTRODUCTION: Limited evidence suggests that serum alkaline phosphatase activity may decrease after cardiac surgery in adults and children. The importance of this finding is not known. Recent studies, however, have identified a potential role for alkaline phosphatase as modulator of inflammation in multiple settings, including during adult cardiopulmonary bypass. We sought to describe the change in alkaline phosphatase activity after cardiothoracic surgery in infants and to assess for a correlation with intensity and duration of post-operative support, markers of inflammation, and short-term clinical outcomes. METHODS: Sub-analysis of a prospective observational study on the kinetics of procalcitonin in 70 infants (≤ 90 days old) undergoing cardiothoracic surgery. Subjects were grouped based on the use of cardiopulmonary bypass and delayed sternal closure. Alkaline phosphatase, procalcitonin, and C-reactive protein (CRP) levels were obtained pre-operation and on post-operative day 1. Mean change in alkaline phosphatase activity was determined in each surgical group. Generalized linear modeling and logistic regression were employed to assess for associations between post-operative alkaline phosphatase activity and post-operative support, inflammation, and short term outcomes. Primary endpoints were vasoactive-inotropic score at 24 hours and length of intubation. Secondary endpoints included procalcitonin/CRP levels on post-operative day 1, length of hospital stay, and cardiac arrest or death. RESULTS: Mean decrease in alkaline phosphatase was 30 U/L (p = 0.01) in the non-bypass group, 114 U/L (p < 0.0001) in the bypass group, and 94 U/L (p < 0.0001) in the delayed sternal closure group. On multivariate analysis, each 10 U/L decrease in alkaline phosphatase activity on post-operative day 1 was independently associated with an increase in vasoactive-inotropic score by 0.7 (p < 0.0001), intubation time by 6% (p < 0.05), hospital stay by 5% (p < 0.05), and procalcitonin by 14% (P < 0.01), with a trend towards increased odds of cardiac arrest or death (OR 1.3; p = 0.06). Post-operative alkaline phosphatase activity was not associated with CRP (p = 0.7). CONCLUSIONS: Alkaline phosphatase activity decreases after cardiothoracic surgery in infants. Low post-operative alkaline phosphatase activity is independently associated with increased procalcitonin, increased vasoactive/inotropic support, prolonged intubation time, and prolonged hospital stay. Alkaline phosphatase may serve as a biomarker and potential modulator of post-operative support and inflammation following cardiothoracic surgery in infants.


Subject(s)
Alkaline Phosphatase/blood , Cardiac Surgical Procedures/adverse effects , Inflammation/enzymology , Postoperative Care , Thoracic Surgical Procedures/adverse effects , Biomarkers/blood , C-Reactive Protein/metabolism , Calcitonin/blood , Calcitonin Gene-Related Peptide , Cardiotonic Agents/therapeutic use , Female , Humans , Infant , Infant, Newborn , Inflammation/etiology , Intubation, Intratracheal , Length of Stay , Male , Prospective Studies , Protein Precursors/blood
8.
Nucleic Acids Res ; 38(Database issue): D563-9, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19884133

ABSTRACT

Ensembl Genomes (http://www.ensemblgenomes.org) is a new portal offering integrated access to genome-scale data from non-vertebrate species of scientific interest, developed using the Ensembl genome annotation and visualisation platform. Ensembl Genomes consists of five sub-portals (for bacteria, protists, fungi, plants and invertebrate metazoa) designed to complement the availability of vertebrate genomes in Ensembl. Many of the databases supporting the portal have been built in close collaboration with the scientific community, which we consider as essential for maintaining the accuracy and usefulness of the resource. A common set of user interfaces (which include a graphical genome browser, FTP, BLAST search, a query optimised data warehouse, programmatic access, and a Perl API) is provided for all domains. Data types incorporated include annotation of (protein and non-protein coding) genes, cross references to external resources, and high throughput experimental data (e.g. data from large scale studies of gene expression and polymorphism visualised in their genomic context). Additionally, extensive comparative analysis has been performed, both within defined clades and across the wider taxonomy, and sequence alignments and gene trees resulting from this can be accessed through the site.


Subject(s)
Computational Biology/methods , Databases, Genetic , Databases, Nucleic Acid , Animals , Computational Biology/trends , Gene Expression , Genome, Bacterial , Genome, Fungal , Genome, Plant , Information Storage and Retrieval/methods , Internet , Invertebrates/genetics , Polymorphism, Genetic , Protein Structure, Tertiary , Software
9.
Br J Cancer ; 105(3): 346-52, 2011 Jul 26.
Article in English | MEDLINE | ID: mdl-21750555

ABSTRACT

BACKGROUND: α(v) integrins are involved in angiogenesis and melanoma tumourigenesis. Intetumumab (CNTO 95) is a fully human anti-α(v)-integrin monoclonal antibody. METHODS: In a multicentre, randomised, phase II study, stage IV melanoma patients were randomised 1:1:1:1 to 1000 mg m(-2) dacarbazine+placebo (n=32), 1000 mg m(-2) dacarbazine+10 mg kg(-1) intetumumab (n=32), 10 mg kg(-1) intetumumab (n=33), or 5 mg kg(-1) intetumumab (n=32) q3w. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), adverse events, and pharmacokinetics. RESULTS: No statistically significant differences in efficacy were observed between groups. In the dacarbazine+placebo, dacarbazine+intetumumab, 10 mg kg(-1) intetumumab, and 5 mg kg(-1) intetumumab groups, median PFS was 1.8, 2.5, 1.4, and 1.4 months; median OS was 8, 11, 15, and 9.8 months; and ORR of complete+partial response was 10, 3, 6, and 0%. Nonlinear intetumumab pharmacokinetics and potential intetumumab-dacarbazine interactions were observed. Transient, asymptomatic, nonrecurring, grade 1-2, uveitic reactions that resolved spontaneously or with topical steroids were seen in 22-30% of intetumumab-treated patients. Low-grade infusion-reaction symptoms (headache, fatigue, nausea, vomiting, fever, chills) were observed, as expected, in 16-73% of dacarbazine-treated patients. No intetumumab-related myelosuppression, laboratory/electrocardiogram abnormalities, or deaths occurred. CONCLUSION: With its favourable safety profile and a nonsignificant trend towards improved OS, intetumumab merits further investigation in advanced melanoma.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Dacarbazine/administration & dosage , Integrin alphaV/immunology , Melanoma/drug therapy , Skin Neoplasms/drug therapy , Aged , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Disease-Free Survival , Female , Humans , Male , Melanoma/mortality , Middle Aged , Uveitis/chemically induced
10.
J Vasc Surg ; 54(3 Suppl): 50S-4S, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21872117

ABSTRACT

Conflicts of interest exist when an arrangement potentially exerts inappropriate influence on decision making or professional judgment, or is perceived to do so, and can thus damage the public trust and undermine the integrity of those decisions. Concerns regarding financial conflicts of interest in the medical arena have reached their height as of late, given that physicians now function in a milieu of complex and delicate relationships with pharmaceutical, biotechnology, and medical device industries. Even when such relationships do not correlate with actual compromise of judgment or patient care, it threatens the credibility of both the health care professional and the institution because of the social perception of the effect of these relationships. Although most institutions in the Western world set forth a code of ethics and conflict-of-interest policies to be followed under threat of termination, the Veterans Health Administration (VHA) presents itself as a unique environment in which conflicts of interest are subject to governmental laws, violation of which may not only result in employment-related discipline, but may be sanctioned by civil and criminal penalties. Moreover, these provisions are developed by a national authoritative organization rather than being institution-specific guidelines. Given that many academic physicians working within the VHA may also have a component of their practice in a University setting, it becomes important to understand the differences in policy between these contexts so as not to threaten the public trust in the veracity of decisions made and, therefore, maintain the integrity of the relationship between physician and patient. This article will review aspects of conflict-of-interest policies in the realm of research, financial relationships, foreign travel, and vendor contracting that are particular to the VHA and make it a unique environment to function in as a physician and scientist.


Subject(s)
Conflict of Interest , Health Care Sector , Interinstitutional Relations , Interprofessional Relations , Quality of Health Care , United States Department of Veterans Affairs , Codes of Ethics , Conflict of Interest/economics , Conflict of Interest/legislation & jurisprudence , Cooperative Behavior , Diffusion of Innovation , Fees and Charges , Gift Giving , Government Regulation , Guidelines as Topic , Health Care Sector/economics , Health Care Sector/ethics , Health Care Sector/legislation & jurisprudence , Health Care Sector/standards , Health Policy , Humans , Interprofessional Relations/ethics , Practice Patterns, Physicians' , Quality of Health Care/economics , Quality of Health Care/ethics , Quality of Health Care/legislation & jurisprudence , Quality of Health Care/standards , Scientific Misconduct , United States , United States Department of Veterans Affairs/economics , United States Department of Veterans Affairs/ethics , United States Department of Veterans Affairs/legislation & jurisprudence , United States Department of Veterans Affairs/standards
11.
Nucleic Acids Res ; 37(Database issue): D690-7, 2009 Jan.
Article in English | MEDLINE | ID: mdl-19033362

ABSTRACT

The Ensembl project (http://www.ensembl.org) is a comprehensive genome information system featuring an integrated set of genome annotation, databases, and other information for chordate, selected model organism and disease vector genomes. As of release 51 (November 2008), Ensembl fully supports 45 species, and three additional species have preliminary support. New species in the past year include orangutan and six additional low coverage mammalian genomes. Major additions and improvements to Ensembl since our previous report include a major redesign of our website; generation of multiple genome alignments and ancestral sequences using the new Enredo-Pecan-Ortheus pipeline and development of our software infrastructure, particularly to support the Ensembl Genomes project (http://www.ensemblgenomes.org/).


Subject(s)
Databases, Genetic , Genomics , Animals , Genetic Variation , Humans , Internet , Sequence Alignment
12.
J Extra Corpor Technol ; 43(3): 157-61, 2011 Sep.
Article in English | MEDLINE | ID: mdl-22164455

ABSTRACT

The use of smaller cannulae for minimally invasive surgery techniques and/or aggressive miniaturization of the cardiopulmonary bypass (CPB) circuitry has necessitated the need to augment venous drainage to achieve adequate flow rates. Vacuum assisted venous drainage (VAVD) has become the dominant method to augment venous drainage. VAVD, however, has been associated with a number of known side effects including increased transmission of gaseous microemboli to the patient, venous line chatter, and increased arterial to venous shunts in the circuit. Historically, our practice has been to monitor the arterial output flow rate and to monitor VAVD by observing venous line chatter and changes in the venous reservoir level. In 2008 our pediatric cardiothoracic service began monitoring venous line flow rates by using a second ultrasonic flow probe placed on the venous line. After 12 months, our staff perfusionists reviewed the impact of monitoring venous line flow rates on VAVD and its known side effects on daily clinical practice. When monitoring venous line flow rates, empiric observation revealed that less overall vacuum pressure was needed for our CPB cases. This novel approach to monitoring venous drainage has aided us in providing optimal vacuum levels and therefore, may reduce some of the known side effects experienced with excessive VAVD.


Subject(s)
Cardiopulmonary Bypass/methods , Ultrasonics/instrumentation , Veins/physiology , Blood Flow Velocity , Cardiopulmonary Bypass/instrumentation , Humans , Suction
13.
J Exp Med ; 142(2): 391-402, 1975 Aug 01.
Article in English | MEDLINE | ID: mdl-49387

ABSTRACT

We have used ferritin-conjugated divalent and monovalent anti-Ig antibodies to study simultaneously, histamine secretion and the ultrastructural distribution and redistribution of Ig receptors on rat peritoneal mast cells. We conclude that (a) divalent anti-Ig is required for both receptor redistribution and for calcium-dependent degranulation and histamine release, (b) divalent anti-Ig induces patching and pinocytosis but not capping of Ig molecules, (c) neither capping nor pinocytosis are required for triggering and if clustering is necessary, then less than 10 Ig molecules are required per cluster, and (d) degranulation (and histamine release) is not an all or none response of the mast cell.


Subject(s)
Antibodies, Anti-Idiotypic/administration & dosage , Binding Sites, Antibody , Histamine Release , Mast Cells/metabolism , Animals , Antibodies , Ascitic Fluid/cytology , Dose-Response Relationship, Drug , Ferritins , Immunoglobulin Fab Fragments , Injections, Intraperitoneal , Male , Mast Cells/ultrastructure , Microscopy, Electron , Pertussis Vaccine/administration & dosage , Rats , Sheep/immunology , gamma-Globulins
14.
J Exp Med ; 162(1): 45-59, 1985 Jul 01.
Article in English | MEDLINE | ID: mdl-2989413

ABSTRACT

We have used Epstein-Barr virus (EBV) infection in vitro to delineate two distinct stages in B cell activation. Previous studies have shown that the BLAST-2 (EBVCS) (EBV cell surface) activation antigen is expressed on a small fraction of B cells within 24 h of stimulation with a variety of agents, including mitogens and EBV. In this study, we have been able to isolate the BLAST-2 (EBVCS)+ cells early after activation/infection with EBV. These cells are small B cells that are actively synthesizing RNA but not DNA, and are, therefore, clearly distinct from large proliferating lymphoblasts. In addition, they contain multiple copies of the EBV genome, express the viral nuclear antigen (EBNA) and, most importantly, proceed to undergo transformation when placed back in culture. By comparison, the BLAST-2 (EBVCS)- population does not undergo transformation, even though a fraction of these cells are activated for RNA synthesis and express EBNA. Thus, using the EBV system, we have been able to show directly that an activated B cell first expresses the BLAST-2 (EBVCS) antigen concomitant with an increase in RNA synthesis, and then subsequently proceeds to differentiate into a proliferating lymphoblast.


Subject(s)
B-Lymphocytes/immunology , Cell Transformation, Viral , Herpesvirus 4, Human/immunology , Lymphocyte Activation , Antigens, Viral , Antimetabolites/pharmacology , B-Lymphocytes/metabolism , DNA/biosynthesis , Genes, Viral , Herpesvirus 4, Human/genetics , Humans , In Vitro Techniques , Models, Biological
15.
J Exp Med ; 168(6): 2059-75, 1988 Dec 01.
Article in English | MEDLINE | ID: mdl-2848918

ABSTRACT

Linear EBV genomes undergo a transition to the circular form characteristic of latency by 16-20 h post-infection. This transition requires that the infected cells be activated to the G1 stage of the cell cycle. Cellular proliferation and expression of the activation marker CD23 were not required. Nevertheless, 36 h post-infection, only cells expressing CD23 contained covalently closed, circular episomes (CCC), at an average of one copy per cell. Since the presence of CD23 at this time is predictive that a cell will immortalize, we suggest that the presence of CCC is required for CD23 expression and subsequent immortalization. The one CCC present in each CD23+ cell did not undergo amplification until well after the cells had acquired all of the characteristic phenotypic markers of immortalization. Therefore, while amplification is not necessary for proliferation and immortalization, circularization of a single genome is crucial to the establishment and maintenance of latency by EBV.


Subject(s)
Antigens, Differentiation, B-Lymphocyte/immunology , B-Lymphocytes/immunology , DNA, Circular/analysis , DNA, Viral/analysis , Herpesviridae Infections/genetics , Herpesvirus 4, Human/genetics , Lymphocyte Activation , Cell Line , Gene Amplification
16.
J Exp Med ; 146(2): 495-508, 1977 Aug 01.
Article in English | MEDLINE | ID: mdl-195004

ABSTRACT

Studies have been performed on in vitro infection by Epstein-Barr virus (EBV) of subpopulations of human lymphocytes. B cells of adult peripheral or fetal cord blood transform with equal efficiency, whether assayed by DNA synthesis induction or by outgrowth of transformed lymphocytes. In contrast, unfractionated adult lymphocytes transform much less efficiently than those from fetal cord. Reconstitution experiments of different cell preparations indicated that this difference was due to a suppression of B-cell proliferation by adult Ig-negative lymphocytes which fetal Ig-negative lymphocytes were unable to perform. Separation of Ig-negative lymphocytes into various subpopulations revealed that the suppression was performed by T cells. Macrophages and null cells play little or no role in suppression. The relevance of this phenomenon to infection and recovery from EBV infection during and after infectious mononucleosis is discussed.


Subject(s)
Cell Transformation, Neoplastic , Herpesvirus 4, Human/immunology , T-Lymphocytes/immunology , Adult , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , Cell Line , DNA, Neoplasm/biosynthesis , Fetal Blood/cytology , Fetal Blood/immunology , Humans , Immunoglobulins , In Vitro Techniques
17.
J Exp Med ; 190(4): 567-76, 1999 Aug 16.
Article in English | MEDLINE | ID: mdl-10449527

ABSTRACT

When Epstein-Barr virus (EBV) infects B cells in vitro, the result is a proliferating lymphoblast that expresses at least nine latent proteins. It is generally believed that these cells are rigorously controlled in vivo by cytotoxic T cells. Consistent with this, the latently infected cells in the peripheral blood of healthy carriers are not lymphoblasts. Rather, they are resting memory B cells that are probably not subject to direct immunosurveillance by cytotoxic T lymphocytes (CTLs). When patients become immunosuppressed, the viral load increases in the peripheral blood. The expansion of proliferating lymphoblasts due to the suppressed CTL response is believed to account for this increase and is considered to be a major risk factor for posttransplant lymphoproliferative disease (PTLD) and AIDS-associated B cell lymphoma. Here we show that there is an increase in the numbers of latently infected cells in the peripheral blood of immunosuppressed patients. However, the cells are not proliferating lymphoblasts. They are all latently infected, resting, memory B cells-the same population of infected cells found in the blood of healthy carriers. These results are discussed in the context of a model for EBV persistence that explains why PTLD is usually limited to the lymph nodes.


Subject(s)
B-Lymphocytes/virology , Herpesvirus 4, Human/isolation & purification , Immunologic Memory , Immunosuppression Therapy , Virus Latency , Cell Cycle , Gene Expression Regulation, Viral , Genome, Viral , Herpesviridae Infections/immunology , Herpesviridae Infections/virology , Humans , Lymphoma, AIDS-Related/etiology , Lymphoproliferative Disorders/etiology , Monitoring, Immunologic , Organ Transplantation/adverse effects , Phenotype , Plasmids , Tumor Virus Infections/immunology , Tumor Virus Infections/virology , Viral Load , Viral Matrix Proteins/biosynthesis , Virus Replication
18.
J Exp Med ; 160(6): 1767-81, 1984 Dec 01.
Article in English | MEDLINE | ID: mdl-6392471

ABSTRACT

A simple purification scheme for shigella cytotoxin was devised, resulting in high yields (approximately 50%) and a 1,300-fold increase in specific activity compared with the initial crude bacterial cell lysate. The purified toxin was enterotoxic in ligated rabbit ileal loops and neurotoxic when injected into the peritoneal cavity of mice. Measurement of specific activity of cytotoxin and enterotoxin demonstrated that these two toxicities copurify during the fractionation procedure. On sodium dodecyl sulfate gel electrophoresis, the toxin migrated as two polypeptide subunits, an A subunit of 32,000 mol wt and a B subunit of 6,500 mol wt. Chemical cross-linking experiments demonstrate that the toxin is a complex consisting of one A and five B subunits with a molecular weight of 64,000. Polyclonal rabbit anti-toxin and anti-subunit B antisera were produced as well as subunit-specific mouse monoclonal antibodies. All antibodies preincubated with toxin neutralized cytotoxic effects in HeLa cell monolayers. In contrast, only A subunit-specific antibodies were able to neutralize toxin prebound to the HeLa cell surface. Antibody to the B subunit also inhibited binding of 125I-labeled toxin to these cells by 94% or more. These data demonstrate that the B subunit is involved in shigella toxin binding to the cell surface.


Subject(s)
Antibodies, Bacterial , Antibodies, Monoclonal , Bacterial Toxins/isolation & purification , Dysentery, Bacillary/physiopathology , Amino Acids/analysis , Animals , Antibody Specificity , Electrophoresis, Polyacrylamide Gel , Female , Macromolecular Substances , Mice , Mice, Inbred BALB C , Molecular Weight , Rabbits , Shiga Toxins , Shigella dysenteriae
19.
J Exp Med ; 184(3): 971-80, 1996 Sep 01.
Article in English | MEDLINE | ID: mdl-9064357

ABSTRACT

More than 90% of adults are latently infected with Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis, a self-limiting lymphoproliferative disease characterized by extensive T cell activation. Reactivation of this herpesvirus during immunosuppression is often associated with oncogenesis. These considerations led us to analyze the early events that occur after exposure of the immune system to EBV. Strong major histocompatibility complex (MHC) class II-dependent but not MHC-restricted, T cell proliferation was observed in vitro in response to autologous, lytically infected EBV-transformed B cells. By measuring the appearance of the early activation marker CD69 on individual T cell V beta subsets, we could demonstrate selective activation of human V beta 13- T cells. This was confirmed with murine T cell hybridomas expressing various human BV genes. While EBV- Burkitt's lymphoma cells were nonstimulatory, they induced V beta-restricted T cell activation after EBV infection. EBV specific activation was also demonstrated in cord blood cells, excluding a recall-antigen response. Thus, all of the characteristics of a superantigen-stimulated response are seen, indicating that induction of the EBV lytic cycle is associated with the expression of a superantigen in B cells. A model is presented proposing a role for the superantigen in infection, latency, and oncogenesis.


Subject(s)
Antigens, Viral/analysis , Herpesvirus 4, Human/immunology , Infectious Mononucleosis/immunology , Superantigens/analysis , Adult , Animals , Antigens, CD/analysis , Antigens, Differentiation, T-Lymphocyte/analysis , B-Lymphocytes/immunology , B-Lymphocytes/virology , Cell Transformation, Viral , HLA-DR Antigens/analysis , Humans , Hybridomas/chemistry , Lectins, C-Type , Mice , Models, Biological , Molecular Sequence Data , T-Lymphocytes/immunology , T-Lymphocytes/virology
20.
J Exp Med ; 184(1): 283-8, 1996 Jul 01.
Article in English | MEDLINE | ID: mdl-8691144

ABSTRACT

Short DNA sequences have been identified, originally in association with Kaposi's sarcoma (KS) biopsies, that are highly homologous to oncogenic, lymphotropic herpesviruses. Recently a virus, Kaposi sarcoma associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8), bearing these sequences has been identified in a cell line derived from a body cavity-based lymphoma. In this report, we show that the same sequences are present in KS biopsies as DNA molecules of a form and size characteristic of latent herpesviruses-large, covalently closed, circular episomes. The genomes migrate with an apparent size larger than the herpesvirus Epstein-Barr virus (172 kb). This form of the viral genome was found in four of four biopsies and three of five peripheral blood samples from KS patients. Linear forms of the viral genome, characteristic of viral replication, were not detected in the biopsies, but were present in the peripheral blood of three out of five patients. The sequences for KSHV/HHV-8 were also detected in the blood of four of five allograft patients and three of five healthy donors without KS suggesting that the virus is widespread throughout the human population.


Subject(s)
Herpesviridae/pathogenicity , Sarcoma, Kaposi/microbiology , Base Sequence , DNA, Circular/analysis , DNA, Viral/analysis , Herpesviridae/growth & development , Humans , Leukocytes, Mononuclear/microbiology , Molecular Sequence Data , Sequence Alignment , Sequence Homology, Nucleic Acid , Virus Latency , Virus Replication
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