Digital Commons Network^™

Intravenous Inoculation Of Silver-Haired Bat Rabies Virus, But Not Of A Canine Strain, Elicits Lethal Encephalophathy In Mice By Fast Brain Invasion Via Neurosecretory Hypothalamic Fibers, Mirjam Ar Preuss, Marie-Luise Faber, Gene S. Tan, Bernhard Dietzschold, Matthias J. Schnell, Eberhard Weihe

Department of Microbiology and Immunology Faculty Papers

No abstract provided.

Neurovirulence Of Polytropic Murine Retrovirus Is Influenced By Two Separate Regions On Opposite Sides Of The Envelope Protein Receptor Binding Domain, Karin E. Peterson, Susan Pourciau, Min Du, Rachel Lacasse, Melissa Pathmajeyan, David J. Poulsen, Mavis Agbandje-Mckenna, Kathy Wehrly, Bruce Chesebro

Biomedical and Pharmaceutical Sciences Faculty Publications

Changes in the envelope proteins of retroviruses can alter the ability of these viruses to infect the central nervous system (CNS) and induce neurological disease. In the present study, nine envelope residues were found to influence neurovirulence of the Friend murine polytropic retrovirus Fr98. When projected on a three-dimensional model, these residues were clustered in two spatially separated groups, one in variable region B of the receptor binding site and the other on the opposite side of the envelope. Further studies indicated a role for these residues in virus replication in the CNS, although the residues did not affect viral …

Contribution Of The Collagen Adhesin Acm To Pathogenesis Of Enterococcus Faecium In Experimental Endocarditis, Sreedhar R Nallapareddy, Kavindra V Singh, Barbara E Murray

Faculty, Staff and Student Publications

Enterococcus faecium is a multidrug-resistant opportunist causing difficult-to-treat nosocomial infections, including endocarditis, but there are no reports experimentally demonstrating E. faecium virulence determinants. Our previous studies showed that some clinical E. faecium isolates produce a cell wall-anchored collagen adhesin, Acm, and that an isogenic acm deletion mutant of the endocarditis-derived strain TX0082 lost collagen adherence. In this study, we show with a rat endocarditis model that TX0082 Deltaacm::cat is highly attenuated versus wild-type TX0082, both in established (72 h) vegetations (P < 0.0001) and for valve colonization 1 and 3 hours after infection (P or=50-fold reduction relative to an Acm producer) were found in three of these five nonadherent isolates, including the sequenced strain TX0016, by quantitative reverse transcription-PCR, indicating that acm transcription is downregulated in vitro in these isolates. However, examination of TX0016 cells obtained directly from infected rat vegetations by flow cytometry showed that Acm was present on 40% of cells grown during infection. Finally, we demonstrated a significant reduction in E. faecium collagen adherence by affinity-purified anti-Acm antibodies from E. faecium endocarditis patient sera, suggesting that Acm may be a potential immunotarget for strategies to control this emerging pathogen.

A Functional Collagen Adhesin Gene, Acm, In Clinical Isolates Of Enterococcus Faecium Correlates With The Recent Success Of This Emerging Nosocomial Pathogen, Sreedhar R Nallapareddy, Kavindra V Singh, Pablo C Okhuysen, Barbara E Murray

Faculty, Staff and Student Publications

Enterococcus faecium recently evolved from a generally avirulent commensal into a multidrug-resistant health care-associated pathogen causing difficult-to-treat infections, but little is known about the factors responsible for this change. We previously showed that some E. faecium strains express a cell wall-anchored collagen adhesin, Acm. Here we analyzed 90 E. faecium isolates (99% acm(+)) and found that the Acm protein was detected predominantly in clinically derived isolates, while the acm gene was present as a transposon-interrupted pseudogene in 12 of 47 isolates of nonclinical origin. A highly significant association between clinical (versus fecal or food) origin and collagen adherence (P

Accelerated High Fidelity Prion Amplification Within And Across Prion Species Barriers, Kristi M. Green, Joaquín Castilla, Tanya S. Seward, Dana L. Napier, Jean E. Jewell, Claudio Soto, Glenn C. Telling

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Experimental obstacles have impeded our ability to study prion transmission within and, more particularly, between species. Here, we used cervid prion protein expressed in brain extracts of transgenic mice, referred to as Tg(CerPrP), as a substrate for in vitro generation of chronic wasting disease (CWD) prions by protein misfolding cyclic amplification (PMCA). Characterization of this infectivity in Tg(CerPrP) mice demonstrated that serial PMCA resulted in the high fidelity amplification of CWD prions with apparently unaltered properties. Using similar methods to amplify mouse RML prions and characterize the resulting novel cervid prions, we show that serial PMCA abrogated a transmission barrier …

Cd5 Plays An Inhibitory Role In The Suppressive Function Of Murine Cd4(+) Cd25(+) T(Reg) Cells., Trivikram Dasu, Joseph E Qualls, Halide Tuna, Chander Raman, Donald A Cohen, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A subset of CD4(+) T cells, the CD4(+) CD25(+) regulatory T (T(reg)) cells in the lymphoid organs and peripheral blood are known to possess suppressive function. Previous in vitro and in vivo studies have indicated that T cell receptor (TCR) signal is required for development of such 'natural regulatory (T(reg)) cells' and for activation of the effector function of CD4(+) CD25(+) regulatory T cells. CD5 is a cell surface molecule present on all T cells and a subtype of B lymphocytes, the B-1 cells, primarily localized to coelomic cavities, Peyer's patches, tonsils and spleen. CD5 acts as a negative regulator …

Cd5 Plays An Inhibitory Role In The Suppressive Function Of Murine Cd4+ Cd25+ TReg Cells, Trivikram Dasu, Joseph E. Qualls, Halide Tuna, Chander Raman, Donald A. Cohen, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A subset of CD4⁺ T cells, the CD4⁺ CD25⁺ regulatory T (T_reg) cells in the lymphoid organs and peripheral blood are known to possess suppressive function. Previous in vitro and in vivo studies have indicated that T cell receptor (TCR) signal is required for development of such ‘natural regulatory (T_reg) cells’ and for activation of the effector function of CD4⁺ CD25⁺ regulatory T cells. CD5 is a cell surface molecule present on all T cells and a subtype of B lymphocytes, the B-1 cells, primarily localized to coelomic cavities, Peyer's patches, …

Distinct Functions Of Autoreactive Memory And Effector Cd4+ T Cells In Experimental Autoimmune Encephalomyelitis, Wassim Elyaman, Pia Kivisäkk, Jay Reddy, Tanuja Chitnis, Khadir Raddassi, Jaime Imitola, Elizabeth Bradshaw, Vijay K. Kuchroo, Hideo Yagita, Mohamed H. Sayegh, Samia J. Khoury

Jay Reddy Publications

The persistence of human autoimmune diseases is thought to be mediated predominantly by memory T cells. We investigated the phenotype and migration of memory versus effector T cells in vivo in experimental autoimmune encephalomyelitis (EAE). We found that memory CD4⁺ T cells up-regulated the activation marker CD44 as well as CXCR3 and ICOS, proliferated more and produced more interferon-γ and less interleukin-17 compared to effector T cells. Moreover, adoptive transfer of memory T cells into T cell receptor (TCR)αβ^-/- recipients induced more severe disease than did effector CD4⁺ T cells with marked central nervous system inflammation and …

Regulation Of The Bioavailability Of Thioredoxin In The Lens By A Specific Thioredoxin-Binding Protein (Tbp-2), Namal P.M. Liyanage, M. Rohan Fernando, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Thioredoxin (TRx) is known to control redox homeostasis in cells. In recent years, a specific TRx binding protein called thioredoxin binding protein-2 (TBP-2) was found in other cell types and it appeared to negatively regulate TRx bioavailability and thereby control TRx biological function. In view of the sensitivity of lens transparency to redox status, proper regulation of TRx bioavailability is of the utmost importance. This study was conducted to examine the presence and function of TBP-2 in human lens epithelial cells (HLE B3). We cloned human lens TBP-2 from a human cDNA library (GenBank accession number AY 594328) and showed …

Neutralization Of Botulinum Neurotoxin By A Human Monoclonal Antibody Specific For The Catalytic Light Chain., Sharad P Adekar, Tsuyoshi Takahashi, R Mark Jones, Fetweh H Al-Saleem, Denise M Ancharski, Michael J Root, B P Kapadnis, Lance L Simpson, Scott K Dessain

Department of Biochemistry and Molecular Biology Faculty Papers

BACKGROUND: Botulinum neurotoxins (BoNT) are a family of category A select bioterror agents and the most potent biological toxins known. Cloned antibody therapeutics hold considerable promise as BoNT therapeutics, but the therapeutic utility of antibodies that bind the BoNT light chain domain (LC), a metalloprotease that functions in the cytosol of cholinergic neurons, has not been thoroughly explored.

METHODS AND FINDINGS: We used an optimized hybridoma method to clone a fully human antibody specific for the LC of serotype A BoNT (BoNT/A). The 4LCA antibody demonstrated potent in vivo neutralization when administered alone and collaborated with an antibody specific for …

Pcr-Based Assay Using Occult Blood Detection Cards For Detection Of Diarrheagenic Escherichia Coli In Specimens From Us Travelers To Mexico With Acute Diarrhea, Kevin A Grimes, Jamal A Mohamed, Herbert L Dupont, Ranjit S Padda, Zhi-Dong Jiang, Jose Flores, Jaime Belkind-Gerson, Francisco G Martinez-Sandoval, Pablo C Okhuysen

Faculty, Staff and Student Publications

Large field studies of travelers' diarrhea for multiple destinations are limited by the need to perform stool cultures on site in a timely manner. A method for the collection, transport, and storage of fecal specimens that does not require immediate processing and refrigeration and that is stable for months would be advantageous. This study was designed to determine if enterotoxigenic Escherichia coli (ETEC) and enteroaggregative E. coli (EAEC) DNA could be identified from cards that were processed for the evaluation of fecal occult blood. U.S. students traveling to Mexico during 2005 to 2007 were monitored for the occurrence of diarrheal …

Critical Involvement Of The Atm-Dependent Dna Damage Response In The Apoptotic Demise Of Hiv-1-Elicited Syncytia, Jean-Luc Perfettini, Roberta Nardacci, Mehdi Bourouba, Frederic Subra, Laurent Gros, Claire Séror, Gwenola Manic, Filippo Rosselli, Alessandra Amendola, Peggy Masdehors, Luciana Chessa, Giuseppe Novelli, David M. Ojcius, Jan Konrad Siwicki, Magdalena Chechlinska, Christian Auclair, Jose R. Regueiro, Hughes De Thé, Marie-Lise Gougeon, Mauro Piacentini, Guido Kroemer

All Dugoni School of Dentistry Faculty Articles

DNA damage can activate the oncosuppressor protein ataxia telangiectasia mutated (ATM), which phosphorylates the histone H2AX within characteristic DNA damage foci. Here, we show that ATM undergoes an activating phosphorylation in syncytia elicited by the envelope glycoprotein complex (Env) of human immunodeficiency virus-1 (HIV-1) in vitro. This was accompanied by aggregation of ATM in discrete nuclear foci that also contained phospho-histone H2AX. DNA damage foci containing phosphorylated ATM and H2AX were detectable in syncytia present in the brain or lymph nodes from patients with HIV-1 infection, as well as in a fraction of blood leukocytes, correlating with viral status. Knockdown …

Prescription Of Medicines By Medical Students Of Karachi, Pakistan: A Cross-Sectional Study, Syed Nabeel Zafar, Reema Syed, Sana Waqar, Faria A. Irani, Sarah Saleem

Community Health Sciences

Background: Prescription of medicines by non-doctors is an issue with serious global implications. To our knowledge prescription of drugs by medical and non-medical students has not been studied before. We aimed to determine the practice and attitudes of drug prescription by medical students and: a) how non-medical students respond to this practice, b) How this compares with the attitudes and practices of non-medical students. Methods: A cross-sectional study was conducted on a sample of 600 students randomly selected from 2 medical and 2 non-medical universities. Ethical requirements were ensured and data was collected using self administered questionnaires. The Chi square …

Cif Is Negatively Regulated By The Tetr Family Repressor Cifr, Daniel P. Maceachran, Bruce A. Stanton, George A. O'Toole

Dartmouth Scholarship

We previously reported that the novel Pseudomonas aeruginosa toxin Cif is capable of decreasing apical membrane expression of the cystic fibrosis transmembrane conductance regulator (CFTR). We further demonstrated that Cif is capable of degrading the synthetic epoxide hydrolase (EH) substrate S-NEPC [(2S,3S)-trans-3-phenyl-2-oxiranylmethyl 4-nitrophenol carbonate], suggesting that Cif may be reducing apical membrane expression of CFTR via its EH activity. Here we report that Cif is capable of degrading the xenobiotic epoxide epibromohydrin (EBH) to its vicinal diol 3-bromo-1,2-propanediol. We also demonstrate that this epoxide is a potent inducer of cif gene expression. We show that the predicted TetR family transcriptional …

Susceptibility Of Chlamydia Trachomatis To The Excipient Hydroxy-Ethylcellulose: Ph And Concentration Dependence Of Antimicrobial Activity, Ali A. Abdul-Sater, David M. Ojcius, M. P. Meyer

All Dugoni School of Dentistry Faculty Articles

Hydroxyethyl cellulose (HEC) is used as a neutral excipient in microbicides used against sexually transmitted pathogens. However, HEC inhibits the infection of cervical epithelial cells by Chlamydia trachomatis at pH 5 in a concentration-dependent manner. At pH 7, infection is inversely dependent on the concentration of HEC, possibly due to pH-dependent calcium sequestration.

A Distinct Role For B1b Lymphocytes In T Cell-Independent Immunity, Kishore R. Alugupalli

Department of Microbiology and Immunology Faculty Papers

Pathogenesis of infectious disease is not only determined by the virulence of the microbe but also by the immune status of the host. Vaccination is the most effective means to control infectious diseases. A hallmark of the adaptive immune system is the generation of B cell memory, which provides a long-lasting protective antibody response that is central to the concept of vaccination. Recent studies revealed a distinct function for B1b lymphocytes, a minor subset of mature B cells that closely resembles that of memory B cells in a number of aspects. In contrast to the development of conventional B cell …

Drug Resistance In Malaria: A Peruvian Research Experience, Ryan Haley

Inquiry Journal 2008

No abstract provided.

Genetic Evidence For An Alternative Citrate-Dependent Biofilm Formation Pathway In Staphylococcus Aureus That Is Dependent On Fibronectin Binding Proteins And The Grars Two-Component Regulatory System, Robert M. Q. Shanks, Michael A. Meehl, Kimberly M. Brothers, Raquel M. Martinez, Niles P. Donegan, Martha L. Graber, Ambrose L. Cheung, George A. O'Toole

Dartmouth Scholarship

We reported previously that low concentrations of sodium citrate strongly promote biofilm formation by Staphylococcus aureus laboratory strains and clinical isolates. Here, we show that citrate promotes biofilm formation via stimulating both cell-to-surface and cell-to-cell interactions. Citrate-stimulated biofilm formation is independent of the ica locus, and in fact, citrate represses polysaccharide adhesin production. We show that fibronectin binding proteins FnbA and FnbB and the global regulator SarA, which positively regulates fnbA and fnbB gene expression, are required for citrate's positive effects on biofilm formation, and citrate also stimulates fnbA and fnbB gene expression. Biofilm formation is also stimulated by several …

Clinical And Microbiological Aspects Of Linezolid Resistance Mediated By The Cfr Gene Encoding A 23s Rrna Methyltransferase, Cesar A Arias, Martha Vallejo, Jinnethe Reyes, Diana Panesso, Jaime Moreno, Elizabeth Castañeda, Maria V Villegas, Barbara E Murray, John P Quinn

Faculty, Staff and Student Publications

The cfr (chloramphenicol-florfenicol resistance) gene encodes a 23S rRNA methyltransferase that confers resistance to linezolid. Detection of linezolid resistance was evaluated in the first cfr-carrying human hospital isolate of linezolid and methicillin-resistant Staphylococcus aureus (designated MRSA CM-05) by dilution and diffusion methods (including Etest). The presence of cfr was investigated in isolates of staphylococci colonizing the patient's household contacts and clinical isolates recovered from patients in the same unit where MRSA CM-05 was isolated. Additionally, 68 chloramphenicol-resistant Colombian MRSA isolates recovered from hospitals between 2001 and 2004 were screened for the presence of the cfr gene. In addition to erm(B), …

Psychiatric Outcomes In A Resident-Run Multidisciplinary Hepatitis C Clinic, Nicole M. Agostino Do, Edward Norris Md, Fapm, Joseph L. Yozviak Do, Facp, Charles M. Brooks Md, Eric J. Gertner Md, Mph, Michael Kaufmann Md

Department of Medicine

No abstract provided.

Method For Treating A Viral Infection Related Or A Chemical Toxin Related Hepatic Injury With Deltorphin D, Peter R. Oeltgen, Paul D. Bishop, Craig J. Mcclain, Shirish Barve

Pathology and Laboratory Medicine Faculty Patents

A method of modulating cytokine mediated hepatic injury by administering compound-D SEQ ID NO:1 to a mammal. A concentration of the compound in the range of about 0.5 mg/kg to about 20 mg/kg in a physiologically acceptable formulation blocks a cytokine cascade. A therapeutic method of modulating cytokine mediated acute inflammatory, trauma induced and toxin induced hepatic injury, particularly via tumor necrosis factor modulation, is thus disclosed.

In Vitro Analysis Of Tobramycin-Treated Pseudomonas Aeruginosa Biofilms On Cystic Fibrosis-Derived Airway Epithelial Cells, Gregory G. Anderson, Sophie Moreau-Marquis, Bruce A. Stanton, George A. O'Toole

Dartmouth Scholarship

P. aeruginosa forms biofilms in the lungs of individuals with cystic fibrosis (CF); however, there have been no effective model systems for studying biofilm formation in the CF lung. We have developed a tissue culture system for growth of P. aeruginosa biofilms on CF-derived human airway cells that promotes the formation of highly antibiotic-resistant microcolonies, which produce an extracellular polysaccharide matrix and require the known abiotic biofilm formation genes flgK and pilB. Treatment of P. aeruginosa biofilms with tobramycin reduced the virulence of the biofilms both by reducing bacterial numbers and by altering virulence gene expression. We performed microarray analysis …

The Effect Of A Nurse-Respiratory Therapist Weaning Protocol On The Duration Of Mechanical Ventilation And The Incidence Of Ventilator-Associated Pneumonia, Andrea Lucas

Theses, Dissertations and Capstones

The purpose of this research study was to show the effectiveness of implementing a standardized nurse-respiratory driven weaning protocol in decreasing the time spent on mechanical ventilation and the incidence of ventilator-associated pneumonia in mechanically ventilated patients compared to using individual physician methods. Chart reviews were performed to compare the incidence of ventilator-associated pneumonia (VAP) prior to the initiation of the nurse-respiratory driven weaning protocol. Sister Callista Roy’s Adaptation theory was used as a framework for this study to show that nurses could promote adaption by using a standardized ventilator weaning protocol. The study did not show statistical significance that …

Fusion, 2008, George Washington University, William H. Beaumont Medical Research Honor Society

Fusion

No abstract provided.

In Vitro Activity Of Tigecycline Against Acinetobacter Baumannii Strains Isolated From Nosocomial Infections, Esragül Akinci, İpek Mumcuoğlu, Pinar Öngürü, F. Nurhayat Bayazit, Sevi̇nç Ersoy Şen, Ayşe Erbay, Neri̇man Balaban, Hürrem Bodur

Turkish Journal of Medical Sciences

Aims: Acinetobacter species usually affect hospitalized patients and are involved in many infections associated with a high mortality rate. Management of infections caused by these strains is very difficult, as the strains often display multiple drug resistance, including carbapenem resistance. Tigecycline is the most recently developed semi-synthetic broad spectrum glycylcycline antibiotic. The present study was conducted to evaluate the in vitro susceptibility of Acinetobacter baumannii strains isolated from the hospitalized patients to tigecycline. Materials and Methods: Acinetobacter isolates were collected from hospitalized patients with documented nosocomial infections between June 2005 and October 2006. Only one isolate per patient was accepted. …

Surveillance Of Nosocomial Infections In Dicle University Hospital: A Ten-Year Experience, Mehmet Faruk Geyi̇k, Sali̇h Hoşoğlu, Celal Ayaz, Mustafa Kemal Çelen, Cemal Üstün

Turkish Journal of Medical Sciences

Aim: The main objective was to recognize the evaluation of surveillance program on the nosocomial infections (NIs) in Dicle University Hospital (DUH) Materials and Methods: A prevalence study was performed prospectively, at the DUH from 1997 to 2006. Active surveillance for NIs were performed by infection control team, using the criteria proposed by the Centers for Diseases Control and Prevention (CDC) and National Nosocomial Infections Surveillance System (NNIS) methodology. This team includes infection control doctor and two nurses, who visited hospital units three times a week. All cases with NI were recorded using a standard data collection form. Results: During …

Microglia And Astrocyte Activation By Toll-Like Receptor Ligands: Modulation By Ppar-Gamma Agonists., Catherine Gurley, Jessica Nichols, Shuliang Liu, Nirmal K. Phulwani, Nilufer Esen, Tammy Kielian

Journal Articles: Pathology and Microbiology

Microglia and astrocytes express numerous members of the Toll-like receptor (TLR) family that are pivotal for recognizing conserved microbial motifs expressed by a wide array of pathogens. Despite the critical role for TLRs in pathogen recognition, when dysregulated these pathways can also exacerbate CNS tissue destruction. Therefore, a critical balance must be achieved to elicit sufficient immunity to combat CNS infectious insults and downregulate these responses to avoid pathological tissue damage. We performed a comprehensive survey on the efficacy of various PPAR-gamma agonists to modulate proinflammatory mediator release from primary microglia and astrocytes in response to numerous TLR ligands relevant …

A Versatile Assay For The Identification Of Rna Silencing Suppressors Based On Complementation Of Viral Movement, Jason G. Powers, Tim L. Sit, Feng Qu, T. Jack Morris, Kook-Hyung Kim, Steven A. Lommel

Nebraska Center for Virology: Faculty Publications

The cell-to-cell movement of Turnip crinkle virus (TCV) in Nicotiana benthamiana requires the presence of its coat protein (CP), a known suppressor of RNA silencing. RNA transcripts of a TCV construct containing a reporter gene (green fluorescent protein) (TCV-sGFP) in place of the CP open reading frame generated foci of three to five cells. TCV CP delivered in trans by Agrobacterium tumefaciens infiltration potentiated movement of TCV-sGFP and increased foci diameter, on average, by a factor of four. Deletion of the TCV movement proteins in TCV-sGFP (construct TCVΔ92-sGFP) abolished the movement complementation ability of TCV CP. Other known suppressors of …

Gliotoxin Production In Aspergillus Fumigatus, Susan Musyimi

Theses and Dissertations

Aspergillus fumigalus is a ubiquitous fungus that causes an infection called aspergillosis in immune-compromised surgery patients (Latge, 2001, 384; Bok et al. 2006). Aspergillosis cases have increased in the past decade due to the increasing number of patients undergoing immunosuppressive therapy and receiving organ transplants (Bok et al. 2006). Although there is still disagreement as to the causative agent of the symptoms accompanying aspergillosis, many scientists suspect that the compound, gliotoxin, plays a major role, hi this study, we compared the amounts of gliotoxin produced from clinical and environmental isolates of A. fumigatus. We hypothesized that the amount of gliotoxin …

A Comprehensive Analysis Of The Naturally Occurring Polymorphisms In Hiv-1 Vpr: Potential Impact On Ctl Epitopes., Alagarsamy Srinivasan, Velpandi Ayyavoo, Sundarasamy Mahalingam, Aarthi Kannan, Anne Boyd, Debduti Datta, Vaniambadi S Kalyanaraman, Anthony Cristillo, Ronald G Collman, Nelly Morellet, Bassel E Sawaya, Ramachandran Murali

Department of Microbiology and Immunology Faculty Papers

The enormous genetic variability reported in HIV-1 has posed problems in the treatment of infected individuals. This is evident in the form of HIV-1 resistant to antiviral agents, neutralizing antibodies and cytotoxic T lymphocytes (CTLs) involving multiple viral gene products. Based on this, it has been suggested that a comprehensive analysis of the polymorphisms in HIV proteins is of value for understanding the virus transmission and pathogenesis as well as for the efforts towards developing anti-viral therapeutics and vaccines. This study, for the first time, describes an in-depth analysis of genetic variation in Vpr using information from global HIV-1 isolates …