Medical Specialties Commons^™

Antiretroviral Therapy (Art) In Clinical Practice: Ethnic Variability In Effectiveness And Tolerability Of Nelfinavir And Two Nucleoside Reverse Transcriptase Inhibitors, Joseph L. Yozviak Do, Facp, B Moran, R Eric Doerfler Np, Cch, William C. Woodward Do

Department of Medicine

No abstract provided.

Identification Of The Transactivation Domain Of The Transcription Factor Sox-2 And An Associated Co-Activator, Tamara K. Nowling, Lance R. Johnson, Matthew S. Wiebe, Angie Rizzino

Nebraska Center for Virology: Faculty Publications

The importance of interactions between Sox and POU transcription factors in the regulation of gene expression is becoming increasingly apparent. Recently, many examples of the involvement of Sox-POU partnerships in transcription have been discovered, including a partnership between Sox-2 and Oct-3. Little is known about the mechanisms by which these factors modulate transcription. To better understand the molecular interactions involved, we mapped the location of the transactivation do-main of Sox-2. This was done in the context of its interaction with Oct-3, as well as its ability to transactivate as a fusion protein linked to the DNA-binding domain of Gal4. Both …

Immune Cd8+ T Cells Prevent Reactivation Of Toxoplasma Gondii Infection In The Immunocompromised Host, Imtiaz A. Khan, William R. Green, Lloyd H. Kasper, Kathy A. Green, Joseph D. Schwartzman

Dartmouth Scholarship

Toxoplasma gondii remains a serious cause of morbidity and mortality in individuals that are immunosuppressed, patients with AIDS in particular. The cellular immune response, especially by gamma interferon (IFN-γ)-producing CD8⁺ T cells, is an essential component of protective immunity against the parasite. In the present study the role of CD8⁺ T cells during the reactivation of Toxoplasma infection in an immunocompromised murine model was evaluated. Chronically infected mice were challenged with LP-BM5 virus, and the kinetics of CD8⁺ T-cell function was studied. At 10 weeks after viral infection, mice showed obvious signs of systemic illness and began …

Differential Transcription Of The Tcpph Operon Confers Biotype-Specific Control Of The Vibrio Cholerae Toxr Virulence Regulon, Yvette M. Murley, Patricia A. Carroll, Karen Skorupski, Ronald K. Taylor, Stephen B. Calderwood

Dartmouth Scholarship

Epidemic strains of Vibrio cholerae O1 are divided into two biotypes, classical and El Tor. In both biotypes, regulation of virulence gene expression depends on a cascade in which ToxR activates expression of ToxT, and ToxT activates expression of cholera toxin and other virulence genes. In the classical biotype, maximal expression of this ToxR regulon in vitro occurs at 30 degrees C at pH 6.5 (ToxR-inducing conditions), whereas in the El Tor biotype, production of these virulence genes only occurs under very limited conditions and not in response to temperature and pH; this difference between biotypes is mediated at the …

Immune Responses Induced By Gene Gun Or Intramuscular Injection Of Dna Vaccines That Express Immunogenic Regions Of The Serine Repeat Antigen From Plasmodium Falciparum, Alexia A. Belperron, David Feltquate, Barbara A. Fox, Toshihiro Horii, David J. Bzik

Dartmouth Scholarship

The liver- and blood-stage-expressed serine repeat antigen (SERA) of Plasmodium falciparum is a candidate protein for a human malaria vaccine. We compared the immune responses induced in mice immunized with SERA-expressing plasmid DNA vaccines delivered by intramuscular (i.m.) injection or delivered intradermally by Gene Gun immunization. Mice were immunized with a pcdna3 plasmid encoding the entire 47-kDa domain of SERA (amino acids 17 to 382) or the N-terminal domain (amino acids 17 to 110) of SERA. Minimal antibody responses were detected following DNA vaccination with the N-terminal domain of SERA, suggesting that the N-terminal domain alone is not highly immunogenic …

Intermittent Antiretroviral Therapy (Art) Can Induce Reduction Of Viral Rebounding During Art-Interruption, Joseph L. Yozviak Do, Facp, R Eric Doerfler Np, Cch, William C. Woodward Do

Department of Medicine

No abstract provided.

Interruption Of Multiple Cellular Processes In Ht-29 Epithelial Cells By Pseudomonas Aeruginosa Exoenzyme S, Joan C. Olson, Jennifer E. Fraylick, Eileen M. Mcguffie, Katherine M. Dolan, Timothy L. Yahr, Dara W. Frank, Timothy S. Vincent

Dartmouth Scholarship

Exoenzyme S (ExoS), an ADP-ribosylating enzyme produced by the opportunistic pathogen Pseudomonas aeruginosa, is directly translocated into eukaryotic cells by bacterial contact. Within the cell, ExoS ADP-ribosylates the cell signaling protein Ras and causes inhibition of DNA synthesis and alterations in cytoskeletal structure. To further understand the interrelationship of the different cellular effects of ExoS, functional analyses were performed on HT-29 epithelial cells after exposure to ExoS-producing P. aeruginosa 388 and the non-ExoS-producing strain 388DeltaS. Two different mechanisms of morphological alteration were identified: (i) a more-transient and less-severe cell rounding caused by the non-ExoS-producing strain 388DeltaS and (ii) a more-severe, …

Attachment Ligands Of Viable Toxoplasma Gondii Induce Soluble Immunosuppressive Factors In Human Monocytes, Jacqueline Y. Channon, Edward I. Suh, Rosanne M. Seguin, Lloyd H. Kasper

Dartmouth Scholarship

Previous studies have demonstrated that surface antigen proteins, in particular SAG-1, of Toxoplasma gondii are important to this parasite as attachment ligands for the host cell. An in vitro assay was developed to test whether these ligands and other secretory proteins are involved in the immune response of human cells to toxoplasma. Human monocytes were infected with tachyzoites in the presence of antiparasite antibodies, and their effect on mitogen-induced lymphoproliferation was examined. The presence of antibody to either parasite-excreted proteins (MIC-1 and MIC-2) or surface proteins (SAG-1 and SAG-2) during infection neutralized the marked decrease seen in mitogen-induced lymphoproliferation in …

Role Of Gamma Interferon In Cellular Immune Response Against Murine Encephalitozoon Cuniculi Infection, Imtiaz A. Khan, Magali Moretto

Dartmouth Scholarship

Microsporidia are obligate intracellular protozoan parasites that cause a wide variety of opportunistic infection in patients with AIDS. Because it is able to grow in vitro, Encephalitozoon cuniculi is currently the best-studied microsporidian. T cells mediate protective immunity against this parasite. Splenocytes obtained from infected mice proliferate in vitro in response to irradiated parasites. A transient state of hyporesponsiveness to parasite antigen and mitogen was observed at day 17 postinfection. This downregulatory response could be partially reversed by addition of nitric oxide (NO) antagonist to the culture. Mice infected withE. cuniculi secrete significant levels of gamma interferon (IFN-γ). Treatment …

Fas-Fasl Interaction Involved In Pathogenesis Of Ocular Toxoplasmosis In Mice, Mark S. Hu, Joseph D. Schwartzman, Grant R. Yeaman, Jane Collins, Rosanne Seguin, Imtiaz A. Khan, Lloyd H. Kasper

Dartmouth Scholarship

Ocular toxoplasmosis is a potentially blinding intraocular inflammation. The intent of this study was to investigate the role of Fas-FasL interaction in a murine model of acquired ocular toxoplasmosis induced by intracameral inoculation of Toxoplasma gondii. Intraocular inflammation, Fas and FasL expression on lymphocytes and on ocular tissues, the occurrence of apoptosis, and the frequency of CD8⁺ and CD4⁺ T cells in the infected eyes were analyzed in C57BL/6 (B6) mice. Susceptibility to parasite-induced intraocular inflammation was observed in Fas-deficient (B6-lpr) and FasL-deficient (B6-gld) mice. Inoculation of 5,000 T. gondii tachyzoites induced significant …

Informing Research On Hiv Prevention: A Consultation, Sharon Fonn, C. Elizabeth Mcgrory

HIV and AIDS

According to a 1998 UNAIDS/WHO report, HIV infection among women is the fastest-growing segment of the AIDS pandemic, especially in developing countries. Unfortunately, the HIV-prevention strategies put forward by the public health community—monogamy, condom use, and treatment of sexually transmitted infections—are not feasible for many women. Women urgently need a means within their personal control to protect themselves against HIV. Recognizing this need, a number of international and nongovernmental organizations and government agencies have called for the development of microbicides, products that women could use vaginally to prevent infection with sexually transmitted infections, particularly HIV. The Population Council is one …

Expression Of Toxoplasma Gondii-Specific Heat Shock Protein 70 During In Vivo Conversion Of Bradyzoites To Tachyzoites, Neide M. Silva, Ricardo T. Gazzinelli, Deise A. O. Silva, Eloisa A. V. Ferro, Lloyd H. Kasper, Jose R. Mineo

Dartmouth Scholarship

Stage conversion between bradyzoites and tachyzoites was investigated in C57BL/6 mice chronically infected with the ME-49 strain of Toxoplasma gondii. In order to promote bradyzoite-tachyzoite conversion, mice were treated in vivo with neutralizing doses of anti-gamma interferon (IFN-gamma) or anti-tumor necrosis factor alpha (TNF-alpha) antibodies. Expression of parasite-specific antigens SAG-1, SAG-2, and heat shock protein 70 (Hsp-70) was visualized in the central nervous system by immunocytochemistry and measured by photometric assay. The immunosuppressive effect of anti-IFN-gamma or anti-TNF-alpha treatment was immediate, leading to parasite stage conversion as indicated by the increased expression of tachyzoite-specific antigens (SAG-1 and SAG-2) and by …

Antigen-Specific Cd8+ T Cells Protect Against Lethal Toxoplasmosis In Mice Infected With Neospora Caninum, Lloyd H. Kasper, Imtiaz A. Khan

Dartmouth Scholarship

Neospora caninum is a coccidial protozoan parasite that appears morphologically indistinguishable from Toxoplasma gondii and that infects a large range of mammals. Both inbred and outbred strains of mice exhibit a high degree of resistance to infection with N. caninum. Three inbred strains of mice (A/J, BALB/c, and C57BL/6) that were infected intraperitoneally with N. caninum were protected against a lethal challenge from T. gondii. Vaccine-induced protection was Neospora dose dependent. A rise in the CD8+ T-cell population in mice that had been vaccinated with N. caninum and challenged with T. gondii was observed. Adoptive transfer of CD8+ T-cell splenocytes …

Chlamydia Trachomatis Infection In The Female Reproductive Tract Of The Rat: Influence Of Progesterone On Infectivity And Immune Response, Charu Kaushic, Andrew D. Murdin, Brian J. Underdown, Charles R. Wira

Dartmouth Scholarship

As the most common cause of sexually transmitted disease in women, chlamydial infections can lead to pelvic inflammatory disease, infertility, and ectopic pregnancy. To better understand the role played by sex hormones in modulating the immune response of the genital tract to microbial infections, we have developed a rat model to study Chlamydia trachomatis infection. Inbred female Lewis rats were primed with progesterone and inoculated by intrauterine instillation of C. trachomatis (mouse pneumonitis strain MoPn) into each uterine horn. When infected animals were examined for the presence of chlamydial antigens 14 days postinfection, both the uterus and vagina were found …

Investigation Of The Roles Of Toxin-Coregulated Pili And Mannose-Sensitive Hemagglutinin Pili In The Pathogenesis Of Vibrio Cholerae O139 Infection, Carol O. Tacket, Ronald K. Taylor, Genevieve Losonsky, Yu Lim

Dartmouth Scholarship

In this study, adult volunteers were fed tcpA and mshA deletion mutants of V. cholerae O139 strain CVD 112 to determine the role of toxin-coregulated pili (TCP) and mannose-sensitive hemagglutinin (MSHA) in intestinal colonization. Eight of 10 volunteers who received CVD 112 or CVD 112 ΔmshA shed the vaccine strains in their stools; the geometric mean peak excretion for both groups was 1.4 × 10⁵ CFU/g of stool. In contrast, only one of nine recipients of CVD 112 ΔtcpA shed vibrios in his stool (P < 0.01); during the first 24 h after inoculation, 3 × 10² CFU/g was recovered from this volunteer. All recipients of CVD …

A Dichotomous Role For Nitric Oxide During Acute Toxoplasma Gondii Infection In Mice, Imtiaz A. Khan, Joseph D. Schwartzman, Tadashi Matsuura, Lloyd H. Kasper

Dartmouth Scholarship

Production of nitric oxide by macrophages is believed to be an important microbicidal mechanism for a variety of intracellular pathogens, including Toxoplasma gondii. Mice with a targeted disruption of the inducible nitric oxide synthase gene (iNOS) were infected orally with T. gondii tissue cysts. Time to death was prolonged compared with parental controls. Histologic analysis of tissue from infected mice showed scattered small foci of inflammation with parasites in various tissues of iNOS−/− mice, whereas tissue from the parental C57BL/6 mice had more extensive tissue inflammation with few visible parasites. In particular, extensive ulceration and necrosis of distal small …

The Role Of Reactive Oxygen Species In The Induction Of Interleukin-8 (Il-8) By Rhinovirus, Matthew Biagioli

MUSC Theses and Dissertations

There is a direct correlation between the severity of common cold symptoms and the concentration of IL-8 in nasal secretions from volunteers with experimental human rhinovirus (hRV) colds. Although these and other data are consistent with the hypothesis that IL-8 is a mediator of common cold symptoms, the mechanism by which IL-8 is elaborated in response to hRV challenge is not understood. This study examined the role of oxidative stress and NF-κB activation in hRV induced IL-8 elaboration. All studies were done in either a transformed respiratory epithelial cell line (Beas-2b) or human lung fibroblasts (MRC-5). Induction of oxidative stress …

Attachment Of Toxoplasma Gondii To Host Cells Is Host Cell Cycle Dependent., Jane Grimwood, Jose R. Mineo, Lloyd H. Kasper

Dartmouth Scholarship

The initial attachment of Toxoplasma tachyzoites to target host cells is an important event in the life cycle of the parasite and hence critical in the pathogenesis of this infection. The efficiency of Toxoplasma attachment to synchronized populations of Chinese hamster ovary cells and bovine kidney cells was investigated by using a glutaraldehyde-fixed host cell assay system. For both cell lines, parasite attachment increased as the synchronized host cells proceeded from the G1 phase to the mid-S phase and then decreased as the cells entered the G2-M boundary. Postulating that these differences in attachment reflect the upregulation of a specific …

Toxin-Coregulated Pilus, But Not Mannose-Sensitive Hemagglutinin, Is Required For Colonization By Vibrio Cholerae O1 El Tor Biotype And O139 Strains., K Helene Thelin, Ronald K. Taylor

Dartmouth Scholarship

The relative contributions of toxin-coregulated pilus (TCP) and cell-associated mannose-sensitive hemagglutinin (MSHA) to the colonization ability of Vibrio cholerae O1 El Tor biotype strains and O139 Bengal strains was determined by using isogenic parental and in-frame deletion mutant pairs in the infant mouse cholera model. Both the El Tor and O139 tcpA mutant strains showed a dramatic defect in colonization as indicated by their competitive indices, whereas deletion of mshA had a negligible effect on colonization in either background.

Toxoplasma Gondii-Induced Immune Suppression By Human Peripheral Blood Monocytes: Role Of Gamma Interferon., Jacqueline Y. Channon, Lloyd H. Kasper

Dartmouth Scholarship

The ability of Toxoplasma gondii to evade the host immune response during primary infection in humans is poorly understood. In murine toxoplasmosis, infected spleen macrophages release soluble factors that mediate a transient immunosuppression, which may allow the parasite to become established. When an enriched population of human monocytes from seronegative individuals was incubated with toxoplasmas in vitro, soluble factors that mediated market suppression of mitogen-induced lymphocyte DNA synthesis were released. Irradiated tachyzoites that do not undergo replication were sufficient stimuli for near-maximal soluble factor release. Up to 50% of the soluble factor-mediated suppression is attributable to a gamma interferon (IFN-gamma)-dependent …

Site-Specific (Local) Delivery Of Antibiotics From Biodegradable Gms Based Implants For The Prevention Of Post-Operative Wound Infections, Saleh Allababidi

MUSC Theses and Dissertations

Systemic administration of prophylactic antibiotics has been reported to significantly decrease, but not eliminate postoperative infections mainly due to the failure in achieving adequate levels of antibiotics at the surgical wound. The local administration guarantees the delivery of adequate levels of antibiotics and is therefore advantageous as a prophylactic measure. Hence, the overall objective of this study was to develop a glyceryl monostearate (GMS) based biocompatible, bioerodible system to provide short term (1-3 days) local delivery of antibiotics. GMS based matrices were prepared by direct compression. Erosion enhancers were incorporated into the GMS matrix to facilitate the bioerosion and bioabsorption …

Survival Of Immunoglobulin G-Opsonized Toxoplasma Gondii In Nonadherent Human Monocytes., Camilo E. Fadul, Jacqueline Y. Channon, Lloyd H. Kasper

Dartmouth Scholarship

Toxoplasma gondii is a protozoan parasite that is able to penetrate human monocytes by either passive uptake during phagocytosis or active penetration. It is expected that immunoglobulin G (IgG) opsonization will target the parasite to macrophage Fc gamma receptors for phagocytic processing and subsequent degradation. Antibody-opsonized T. gondii tachyzoites were used to infect nonadherent and adherent human monocytes obtained from the peripheral blood of seronegative individuals. The infected monocytes were evaluated for the presence of intracellular parasites and the degree of parasiticidal activity. A marked difference in both the numbers of infected macrophages and numbers of parasites per 100 macrophages …

Polyclonal Mycobacterium Avium Infections In Patients With Aids: Variations In Antimicrobial Susceptibilities Of Different Strains Of M. Avium Isolated From The Same Patient., C Fordham Von Reyn, Nicholas J. Jacobs, Robert D. Arbeit, Joe N. Maslow, S Niemczyk

Dartmouth Scholarship

Broth microdilution MICs were determined for pairs of strains isolated from five AIDS patients with polyclonal Mycobacterium avium infection. Four (80%) of the five patients were infected simultaneously with strains having different antimicrobial susceptibility patterns. These findings have implications for the interpretation of susceptibility data in M. avium prophylaxis and treatment trials.

Thrombolytic Therapy In Acute Myocardial Infarction In Pakistan., M. Asad Karim, Ata Ata-Ur- Rehman Qureshi, Syed Faisal Mahmood, J. Akhter

Department of Medicine

To characterize features of acute myocardial infarction (AMI) in a Pakistani population, and assess the role of thrombolysis in our country, we studied 194 consecutive admitted patients with enzyme positive AMI. Males were affected three times more frequently; women, although affected less, had a higher incidence of complications than men. Premature coronary artery disease (CAD) was present in 50% patients presenting with AMI. An unusually high incidence of anterior wall myocardial infarction (39%) was seen. Complications were frequent with a predominance of LV failure symptoms. Cardiogenic shock was associated with a very high mortality, in excess of 93%. Streptokinase (SK) …

Media Components Influence Viral Gene Expression Assays In Human Fetal Astrocyte Cultures, Micheline Mccarthy, Charles Wood, Larisa Fedoseyeva, Scott R. Whittemore

Nebraska Center for Virology: Faculty Publications

In vitro neurovirological studies of viral infectivity or viral gene expression may be confounded by the mulHple neural cell types and/or fibrob last contamination present in early passage cultures prepared from dissociated human central nervous system (eNS) tissue. We have developed highly enriched astrocyte cultures for neurovirological study by culturing in a serum-free defined medium, 816, supplemented with basic fibroblast growth factor (FGF-2). Subculture in this medium selects against fibroblast proliferation and favors sustained proliferation of a highly enriched glial fibrillary acidic protein (GFAP)-positive cell population. These astrocytes support productive replication of cytomegalovirus (CMV) and transient expression of transfected CMVand …

Symptoms Six Weeks After Covid-19 Are Reduced Among Us Health Care Personnel Receiving Additional Vaccine Doses During The Omicron Period, December 2021-April 2022., Nicholas M. Mohr, Ian D. Plumb, Eliezer Santos León, Malea Pinckney, Karisa K. Harland, Anusha Krishnadasan, Karin F. Hoth, Fernand Rwamwejo, John P. Haran, Melissa Briggs-Hagen, Eric Kontowicz, David A. Talan

Jefferson Hospital Staff Papers and Presentations

BACKGROUND: The objective of this study was to test the hypothesis that subsequent doses of the coronavirus disease 2019 (COVID-19) vaccine are associated with lower incidence of COVID-19-like symptoms at 6 weeks after infection.

METHODS: This study was a case-control analysis of health care personnel in an ongoing multicenter COVID-19 vaccine effectiveness study. We enrolled participants at the time of COVID-19-like symptoms between December 19, 2021, and April 27, 2022, which corresponded to the early Omicron-predominant period after original monovalent severe acute respiratory syndrome coronavirus 2 additional vaccination doses became available. Our outcome was self-reported symptoms completed 6 weeks after …

Impairment Of The Cellular Immune Response In Acute Murine Toxoplasmosis: Regulation Of Interleukin 2 Production And Macrophage-Mediated Inhibitory Effects., Sakhina Haque, Imtiaz Khan, Azizul Haque, Lloyd Kasper

Dartmouth Scholarship

Depression of the cellular immune response to Toxoplasma gondii has been reported in both mice and humans. The present study was undertaken to determine the kinetics and mechanism of the observed downregulation of interleukin 2 (IL-2) production during experimental murine toxoplasmosis. For these investigations, the cell-mediated immune response to the wild type (PTg) was compared with that to the less-virulent mutant parasite (PTgB), which is deficient in the major surface antigen, p30 (SAG-1). Spleen cells from infected A/J mice failed to proliferate in response to Toxoplasma antigens during the first week of infection. Both PTg- and PTgB-infected A/J mice exhibited …

Polyclonal Infections Due To Mycobacterium Avium Complex In Patients With Aids Detected By Pulsed-Field Gel Electrophoresis Of Sequential Clinical Isolates., Alexander M. Slutsky, Robert D. Arbeit, Thomas W. Barber, Josiah Rich, C Fordham Von Reyn

Dartmouth Scholarship

Invasive infection with organisms of the Mycobacterium avium complex (MAC) is common among patients with advanced human immunodeficiency virus infection. In previous studies, we analyzed multiple individual colonies of MAC isolated from specimens obtained at the same time and observed that 14 to 20% of patients are simultaneously infected with more than one strain. In this study, we examined sequential isolates from 12 patients with AIDS who had two or more MAC isolates available from clinical specimens collected more than 1 week apart; the intervals between the first and last specimens ranged from 8 to 192 (median, 46) days. For …

Interleukin-12 Enhances Murine Survival Against Acute Toxoplasmosis., Imtiaz A. Khan, Tadashi Matsuura, Lloyd H. Kasper

Dartmouth Scholarship

Protective immunity against Toxoplasma gondii is mediated by the host cellular immune response. Interleukin-12 (IL-12), a recently described cytokine that stimulates NK cells to produce gamma interferon (IFN-gamma), is able to enhance host protection against this parasite in SCID mice. Administration of IL-12 to A/J mice significantly increased survival over that of control mice when IL-12 was delivered early in the course of acute infection. If it was administered at day 3 or thereafter, there was no observed difference in mortality between treated and control mice. Antibody depletion of IL-12 increased susceptibility to infection, as measured by mortality, only when …

Book Review: The Baculovirus Expression System: A Laboratory Guide (1992) King, L. A. & Possee, R. D., David D. Dunigan

Nebraska Center for Virology: Faculty Publications

The power of molecular biology is unleashed with the ability to clone and sequence genes, and then express these genes in heterologous systems. This sets the stage for the full analysis of proteins that are otherwise difficult to isolate and/or purify, especially when present at very low copy number per cell or when isolated from relatively precious materials. Overexpression of protein is now possible in a number of systems including prokaryotes (e.g., E. coli) and various eukaryotes (yeast, insects, and plants). The issue then becomes, which system (1) most closely reflects the homologous expression with respect to posttranslational modifications, …