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Articles 4261 - 4290 of 4349

Full-Text Articles in Medical Sciences

Identification Of The Vibrio Cholerae Enterobactin Receptors Vcta And Irga: Irga Is Not Required For Virulence, Alexandra R. Mey, Elizabeth E. Wyckoff, Amanda G. Oglesby, Eva Rab, Ronald K. Taylor, Shelley M. Payne Jul 2002

Identification Of The Vibrio Cholerae Enterobactin Receptors Vcta And Irga: Irga Is Not Required For Virulence, Alexandra R. Mey, Elizabeth E. Wyckoff, Amanda G. Oglesby, Eva Rab, Ronald K. Taylor, Shelley M. Payne

Dartmouth Scholarship

The gram-negative enteric pathogen Vibrio cholerae requires iron for growth. V. cholerae has multiple iron acquisition systems, including utilization of heme and hemoglobin, synthesis and transport of the catechol siderophore vibriobactin, and transport of several siderophores that it does not itself make. One siderophore that V. cholerae transports, but does not make, is enterobactin. Enterobactin transport requires TonB and is independent of the vibriobactin receptor ViuA. In this study, two candidate enterobactin receptor genes, irgA (VC0475) and vctA (VCA0232), were identified by analysis of the V. cholerae genomic sequence. A single mutation in either of these genes did not significantly …

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Treatment With Soluble Interleukin-15ralpha Exacerbates Intracellular Parasitic Infection By Blocking The Development Of Memory Cd8+ T Cell Response, Imtiaz A. Khan, Magali Moretto, Xiao-Qing Wei, Martha Williams, Joseph D. Schwartzman, F Y. Liew Jun 2002

Treatment With Soluble Interleukin-15ralpha Exacerbates Intracellular Parasitic Infection By Blocking The Development Of Memory Cd8+ T Cell Response, Imtiaz A. Khan, Magali Moretto, Xiao-Qing Wei, Martha Williams, Joseph D. Schwartzman, F Y. Liew

Dartmouth Scholarship

Interferon (IFN)-γ–producing CD8+ T cells are important for the successful resolution of the obligate intracellular parasite Toxoplasma gondii by preventing the reactivation or controlling a repeat infection. Previous reports from our laboratory have shown that exogenous interleukin (IL)-15 treatment augments the CD8+ T cell response against the parasite. However, the role of endogenous IL-15 in the proliferation of activated/memory CD8+ T cells during toxoplasma or any other infection is unknown. In this study, we treated T. gondii immune mice with soluble IL-15 receptor α (sIL-15Rα) to block the host endogenous IL-15. The treatment markedly reduced the ability …

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Stretch-Induced Calcium Release In Smooth Muscle., Guangju Ji, Robert J Barsotti, Morris E Feldman, Michael I Kotlikoff Jun 2002

Stretch-Induced Calcium Release In Smooth Muscle., Guangju Ji, Robert J Barsotti, Morris E Feldman, Michael I Kotlikoff

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Smooth muscle cells undergo substantial increases in length, passively stretching during increases in intraluminal pressure in vessels and hollow organs. Active contractile responses to counteract increased transmural pressure were first described almost a century ago (Bayliss, 1902) and several mechanisms have been advanced to explain this phenomenon. We report here that elongation of smooth muscle cells results in ryanodine receptor-mediated Ca(2+) release in individual myocytes. Mechanical elongation of isolated, single urinary bladder myocytes to approximately 120% of slack length (DeltaL = 20) evoked Ca(2+) release from intracellular stores in the form of single Ca(2+) sparks and propagated Ca(2+) waves. Ca(2+) …

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Characterization Of Subcellular Localization And Stability Of A Splice Variant Of G Alpha I2., Philip B Wedegaertner May 2002

Characterization Of Subcellular Localization And Stability Of A Splice Variant Of G Alpha I2., Philip B Wedegaertner

Department of Microbiology and Immunology Faculty Papers

BACKGROUND: Alternative mRNA splicing of alpha(i2), a heterotrimeric G protein alpha subunit, has been shown to produce an additional protein, termed salpha(i2). In the salpha(i2) splice variant, 35 novel amino acids replace the normal C-terminal 24 amino acids of alpha(i2). Whereas alpha(i2) is found predominantly at cellular plasma membranes, salpha(i2) has been localized to intracellular Golgi membranes, and the unique 35 amino acids of salpha(i2) have been suggested to constitute a specific targeting signal. RESULTS: This paper proposes and examines an alternative hypothesis: disruption of the normal C-terminus of alpha(i2) produces an unstable protein that fails to localize to plasma …

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Fibroblast Growth Factor–Specific Modulation Of Cellular Response By Syndecan-4, Arie Horowitz, Eugene Tkachenko, Michael Simons May 2002

Fibroblast Growth Factor–Specific Modulation Of Cellular Response By Syndecan-4, Arie Horowitz, Eugene Tkachenko, Michael Simons

Dartmouth Scholarship

Proteoglycans participate in growth factor interaction with the cell surface through their heparan sulfate chains (HS), but it is not known if they are otherwise involved in growth factor signaling. It appears now that the syndecan-4 core protein, a transmembrane proteoglycan shown previously to bind phosphatidylinositol 4,5-bisphosphate (PIP(2)) and activate PKC alpha, participates in mediating the effects of fibroblast growth factor (FGF)2 on cell function. Mutations in the cytoplasmic tail of syndecan-4 that either reduced its affinity to PIP(2) (PIP(2)(-)) or disrupted its postsynaptic density 95, disk large, zona occludens-1 (PDZ)-dependent binding (PDZ(-)) produced a FGF2-specific dominant negative phenotype in …

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Ube1l Is A Retinoid Target That Triggers Pml/Rarα Degradation And Apoptosis In Acute Promyelocytic Leukemia, Sutisak Kitareewan, Ian Pitha-Rowe, David Sekula, Christopher H. Lowrey, Michael J. Nemeth, Todd R. Golub, Sarah J. Freemantle, Ethan Dmitrovsky Mar 2002

Ube1l Is A Retinoid Target That Triggers Pml/Rarα Degradation And Apoptosis In Acute Promyelocytic Leukemia, Sutisak Kitareewan, Ian Pitha-Rowe, David Sekula, Christopher H. Lowrey, Michael J. Nemeth, Todd R. Golub, Sarah J. Freemantle, Ethan Dmitrovsky

Dartmouth Scholarship

All-trans-retinoic acid (RA) treatment induces remissions in acute promyelocytic leukemia (APL) cases expressing the t(15;17) product, promyelocytic leukemia (PML)/RA receptor α (RARα). Microarray analyses previously revealed induction of UBE1L (ubiquitin-activating enzyme E1-like) after RA treatment of NB4 APL cells. We report here that this occurs within 3 h in RA-sensitive but not RA-resistant APL cells, implicating UBE1L as a direct retinoid target. A 1.3-kb fragment of the UBE1L promoter was capable of mediating transcriptional response to RA in a retinoid receptor-selective manner. PML/RARα, a repressor of RA target genes, abolished this UBE1L promoter activity. A hallmark of …

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Short-Lived And Long-Lived Bone Marrow Plasma Cells Are Derived From A Novel Precursor Population, Brian P. O'Connor, Marilia Cascalho, Randolph J. Noelle Mar 2002

Short-Lived And Long-Lived Bone Marrow Plasma Cells Are Derived From A Novel Precursor Population, Brian P. O'Connor, Marilia Cascalho, Randolph J. Noelle

Dartmouth Scholarship

The contribution that long-lived bone marrow (BM) plasma cells (PCs) provide to enduring humoral immunity has been underscored by a number of recent studies. However, little is known about the immediate precursors that give rise to long-lived PCs in the BM of immune individuals. We have identified subsets of antigen-experienced B cells within the immune BM that are precursors to PCs. These PC precursors arise in the BM 14 days after immunization and persist for greater than 9 months. Phenotypically distinct subsets of PC precursors give rise to short-lived or long-lived PCs. The differentiation of PC precursors to PCs occurs …

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Cd8+-T-Cell Immunity Against Toxoplasma Gondii Can Be Induced But Not Maintained In Mice Lacking Conventional Cd4+ T Cells, Lori Casciotti, Kenneth H. Ely, Martha E. Williams, Imtiaz A. Khan Feb 2002

Cd8+-T-Cell Immunity Against Toxoplasma Gondii Can Be Induced But Not Maintained In Mice Lacking Conventional Cd4+ T Cells, Lori Casciotti, Kenneth H. Ely, Martha E. Williams, Imtiaz A. Khan

Dartmouth Scholarship

T-cell immunity is critical for survival of hosts infected with Toxoplasma gondii. Among the cells in the T-cell population, CD8+ T cells are considered the major effector cells against this parasite. It is believed that CD4+ T cells may be crucial for induction of the CD8+-T-cell response against T. gondii. In the present study, CD4−/− mice were used to evaluate the role of conventional CD4+ T cells in the immune response against T. gondii infection. CD4−/− mice infected with T. gondii exhibited lower gamma interferon (IFN-γ) messages in the majority of their …

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Positive And Negative Roles Of Cd72 In B Cell Function., Hsin-Jung Wu, Subbarao Bondada Jan 2002

Positive And Negative Roles Of Cd72 In B Cell Function., Hsin-Jung Wu, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Regulation of B cell activation depends on integration of signals transmitted by the B cell receptor (BCR) and a variety of co-receptors. CD72 is a B cell co-receptor that is expressed in all stages of B cell development except plasma cells. Ligation of CD72 enhances B cell growth and differentiation. Recently, the class IV semaphoring, CD100, has been identified as the natural ligand for CD72. Cytoplasmic domain of CD72 has been shown to be associated with SHP-1 leading to the proposal that the positive effects of CD72 on B cell response may result from sequestration of negative signals from BCR. …

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Transcriptional Interference By Independently Regulated Genes Occurs In Any Relative Arrangement Of The Genes And Is Influenced By Chromosomal Integration Position, Susan K. Eszterhas, Eric E. Bouhassira, David I. K. Martin, Steven Fiering Jan 2002

Transcriptional Interference By Independently Regulated Genes Occurs In Any Relative Arrangement Of The Genes And Is Influenced By Chromosomal Integration Position, Susan K. Eszterhas, Eric E. Bouhassira, David I. K. Martin, Steven Fiering

Dartmouth Scholarship

Transcriptional interference is the influence, generally suppressive, of one active transcriptional unit on another unit linked in cis. Its wide occurrence in experimental systems suggests that it may also influence transcription in many loci, but little is known about its precise nature or underlying mechanisms. Here we report a study of the interaction of two nearly identical transcription units juxtaposed in various arrangements. Each reporter gene in the constructs has its own promoter and enhancer and a strong polyadenylation signal. We used recombinase-mediated cassette exchange (RMCE) to insert the constructs into previously tagged genomic sites in cultured cells. This …

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Analysis Of Mitotic Microtubule-Associated Proteins Using Mass Spectrometry Identifies Astrin, A Spindle-Associated Protein, Gary J. Mack, Duane A. Compton Dec 2001

Analysis Of Mitotic Microtubule-Associated Proteins Using Mass Spectrometry Identifies Astrin, A Spindle-Associated Protein, Gary J. Mack, Duane A. Compton

Dartmouth Scholarship

We purified microtubules from a mammalian mitotic extract and obtained an amino acid sequence from each microtubule-associated protein by using mass spectrometry. Most of these proteins are known spindle-associated components with essential functional roles in spindle organization. We generated antibodies against a protein identified in this collection and refer to it as astrin because of its association with astral microtubule arrays assembled in vitro. Astrin is approximately 134 kDa, and except for a large predicted coiled-coil domain in its C-terminal region it lacks any known functional motifs. Astrin associates with spindle microtubules as early as prophase where it concentrates at …

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Evaluation Of Cholera Vaccines Formulated With Toxin-Coregulated Pilin Peptide Plus Polymer Adjuvant In Mice, Jia-Yan Wu, William F. Wade, Ronald K. Taylor Dec 2001

Evaluation Of Cholera Vaccines Formulated With Toxin-Coregulated Pilin Peptide Plus Polymer Adjuvant In Mice, Jia-Yan Wu, William F. Wade, Ronald K. Taylor

Dartmouth Scholarship

Cholera is an acute diarrheal disease that is caused by the gram-negative bacterium Vibrio cholerae. The low efficacy of currently available killed-whole-cell vaccines and the reactinogenicity coupled with potential reversion of live vaccines have thus far precluded widespread vaccination for the control of cholera. Recent studies on the molecular nature of the virulence components that contribute to V. cholerae pathogenesis have provided insights into possible approaches for the development of a defined subunit cholera vaccine. Genetic analysis has demonstrated that the toxin-coregulated pilus (TCP) is the major factor that contributes to colonization of the human intestine by V. cholerae. In …

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Immune Response Genes Modulate Serologic Responses To Vibrio Cholerae Tcpa Pilin Peptides, Michael D. Meeks, Terri K. Wade, Ronald K. Taylor, William F. Wade Dec 2001

Immune Response Genes Modulate Serologic Responses To Vibrio Cholerae Tcpa Pilin Peptides, Michael D. Meeks, Terri K. Wade, Ronald K. Taylor, William F. Wade

Dartmouth Scholarship

Cholera is an enteric disease caused by Vibrio cholerae. Toxin-coregulated pilus (TCP), a type 4 pilus expressed by V. cholerae, is a cholera virulence factor that is required for host colonization. The TCP polymer is composed of subunits of TcpA pilin. Antibodies directed against TcpA are protective in animal models of cholera. While natural or recombinant forms of TcpA are difficult to purify to homogeneity, it is anticipated that synthesized TcpA peptides might serve as immunogens in a subunit vaccine. We wanted to assess the potential for effects of the immune response (Ir) gene that could complicate a peptide-based …

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Anti-Class Ii Monoclonal Antibody-Targeted Vibrio Cholerae Tcpa Pilin: Modulation Of Serologic Response, Epitope Specificity, And Isotype, Jia-Yan Wu, Ronald K. Taylor, William F. Wade Dec 2001

Anti-Class Ii Monoclonal Antibody-Targeted Vibrio Cholerae Tcpa Pilin: Modulation Of Serologic Response, Epitope Specificity, And Isotype, Jia-Yan Wu, Ronald K. Taylor, William F. Wade

Dartmouth Scholarship

Toxin-coregulated pilus (TCP) is a colonization factor required for cholera infection. It is not a strong immunogen when delivered in the context of whole cells, yet pilus subunits or TcpA derivative synthetic peptides induce protective responses. We examined the efficacy of immunizing mice with TCP conjugated to anti-class II monoclonal antibodies (MAb) with or without the addition of cholera toxin (CT) or anti-CD40 MAb to determine if the serologic response to TcpA could be manipulated. Anti-class II MAb-targeted TCP influenced the anti-TCP peptide serologic response with respect to titer and isotype. Responses to TcpA peptide 4 were induced with class …

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Evaluation Of A Tetracycline-Inducible Promoter In Staphylococcus Aureus In Vitro And In Vivo And Its Application In Demonstrating The Role Of Sigb In Microcolony Formation, B. T. Bateman, N. P. Donegan, T. M. Jarry, M. Palma Dec 2001

Evaluation Of A Tetracycline-Inducible Promoter In Staphylococcus Aureus In Vitro And In Vivo And Its Application In Demonstrating The Role Of Sigb In Microcolony Formation, B. T. Bateman, N. P. Donegan, T. M. Jarry, M. Palma

Dartmouth Scholarship

An inducible promoter system provides a powerful tool for studying the genetic basis for virulence. A variety of inducible systems have been used in other organisms, including pXyl-xylR-inducible promoter, the pSpac-lacI system, and the arabinose-inducible PBAD promoter, but each of these systems has limitations in its application to Staphylococcus aureus. In this study, we demonstrated the efficacy of a tetracycline-inducible promoter system in inducing gene expression in S. aureus in vitro and inside epithelial cells as well as in an animal model of infection. Using the xyl/tetO promoter::gfpuvr fusion carried on a shuttle …

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Proteolytic Release Of Cd44 Intracellular Domain And Its Role In The Cd44 Signaling Pathway., I Okamoto, Y Kawano, D Murakami, T Sasayama, N Araki, T Miki, A J Wong, H Saya Nov 2001

Proteolytic Release Of Cd44 Intracellular Domain And Its Role In The Cd44 Signaling Pathway., I Okamoto, Y Kawano, D Murakami, T Sasayama, N Araki, T Miki, A J Wong, H Saya

Department of Microbiology and Immunology Faculty Papers

CD44 is a widely distributed cell surface adhesion molecule and is implicated in diverse biological processes. However, the nature of intracellular signaling triggered by CD44 remains to be elucidated. Here, we show that CD44 undergoes sequential proteolytic cleavage in the ectodomain and intracellular domain, resulting in the release of a CD44 intracellular domain (ICD) fragment. Consequently, CD44ICD acts as a signal transduction molecule, where it translocates to the nucleus and activates transcription mediated through the 12-O-tetradecanoylphorbol 13-acetate-responsive element, which is found in numerous genes involved in diverse cellular processes. Expression of an uncleavable CD44 mutant as well as metalloprotease inhibitor …

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Distinct Retrieval And Retention Mechanisms Are Required For The Quality Control Of Endoplasmic Reticulum Protein Folding, Shilpa Vashist, Woong Kim, William J. Belden, Eric D. Spear, Charles Barlowe, Davis T.W. Ng Oct 2001

Distinct Retrieval And Retention Mechanisms Are Required For The Quality Control Of Endoplasmic Reticulum Protein Folding, Shilpa Vashist, Woong Kim, William J. Belden, Eric D. Spear, Charles Barlowe, Davis T.W. Ng

Dartmouth Scholarship

Proteins destined for the secretory pathway must first fold and assemble in the lumen of endoplasmic reticulum (ER). The pathway maintains a quality control mechanism to assure that aberrantly processed proteins are not delivered to their sites of function. As part of this mechanism, misfolded proteins are returned to the cytosol via the ER protein translocation pore where they are ubiquitinated and degraded by the 26S proteasome. Previously, little was known regarding the recognition and targeting of proteins before degradation. By tracking the fate of several mutant proteins subject to quality control, we demonstrate the existence of two distinct sorting …

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Eliciting The Low-Activity Aldehyde Dehydrogenase Asian Phenotype By An Antisense Mechanism Results In An Aversion To Ethanol., E Garver, Tu Gc, Q N Cao, M Aini, F Zhou, Y Israel Sep 2001

Eliciting The Low-Activity Aldehyde Dehydrogenase Asian Phenotype By An Antisense Mechanism Results In An Aversion To Ethanol., E Garver, Tu Gc, Q N Cao, M Aini, F Zhou, Y Israel

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

A mutation in the gene encoding for the liver mitochondrial aldehyde dehydrogenase (ALDH2-2), present in some Asian populations, lowers or abolishes the activity of this enzyme and results in elevations in blood acetaldehyde upon ethanol consumption, a phenotype that greatly protects against alcohol abuse and alcoholism. We have determined whether the administration of antisense phosphorothioate oligonucleotides (ASOs) can mimic the low-activity ALDH2-2 Asian phenotype. Rat hepatoma cells incubated for 24 h with an antisense oligonucleotide (ASO-9) showed reductions in ALDH2 mRNA levels of 85% and ALDH2 (half-life of 22 h) activity of 55% equivalent to a >90% inhibition in ALDH2 …

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Discrimination Of Computer-Graphic Stimuli By Mice: A Method For The Behavioral Characterization Of Transgenic And Gene-Knockout Models., T J Bussey, L M Saksida, L A Rothblat Aug 2001

Discrimination Of Computer-Graphic Stimuli By Mice: A Method For The Behavioral Characterization Of Transgenic And Gene-Knockout Models., T J Bussey, L M Saksida, L A Rothblat

Brain and Mind Institute Researchers' Publications

An automated method is described for the behavioral testing of mice in an apparatus that allows computer-graphic stimulus material to be presented. Mice responded to these stimuli by making a nose-poke toward a computer monitor that was equipped with a touchscreen attachment for detecting responses. It was found that C57BL/6 mice were able to solve single-pair visual discriminations as well as 3-pair concurrent visual discriminations. The finding that mice are capable of complex visual discriminations introduces the possibility of testing mice on nonspatial tasks that are similar to those used with rats, monkeys, and humans. Furthermore, the method seems particularly …

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Sart, A Repressor Of Α-Hemolysin In Staphylococcus Aureus, Katherine A. Schmidt, Adhar C. Manna, Steven Gill, Ambrose L. Cheung Aug 2001

Sart, A Repressor Of Α-Hemolysin In Staphylococcus Aureus, Katherine A. Schmidt, Adhar C. Manna, Steven Gill, Ambrose L. Cheung

Dartmouth Scholarship

In searching the Staphylococcus aureus genome, we found several homologs to SarA. One of these genes, sarT, codes for a basic protein with 118 residues and a predicted molecular size of 16,096 Da. Northern blot analysis revealed that the expression of sarT was repressed by sarA and agr. An insertion sarT mutant generated in S. aureus RN6390 and 8325-4 backgrounds revealed minimal effect on the expression of sarR and sarA. The RNAIII level was notably increased in the sarT mutant, particularly in postexponential-phase cells, while the augmentative effect on RNAII was less. SarT repressed the expression of alpha-hemolysin, as determined …

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The Toxoplasma Gondii Protein Rop2 Mediates Host Organelle Association With The Parasitophorous Vacuole Membrane, Anthony P. Sinai, Keith A. Joiner Jul 2001

The Toxoplasma Gondii Protein Rop2 Mediates Host Organelle Association With The Parasitophorous Vacuole Membrane, Anthony P. Sinai, Keith A. Joiner

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Toxoplasma gondii replicates within a specialized vacuole surrounded by the parasitophorous vacuole membrane (PVM). The PVM forms intimate interactions with host mitochondria and endoplasmic reticulum (ER) in a process termed PVM–organelle association. In this study we identify a likely mediator of this process, the parasite protein ROP2. ROP2, which is localized to the PVM, is secreted from anterior organelles termed rhoptries during parasite invasion into host cells. The NH2-terminal domain of ROP2 (ROP2hc) within the PVM is exposed to the host cell cytosol, and has characteristics of a mitochondrial targeting signal. In in vitro assays, ROP2hc is …

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Marek's Disease Virus (Mdv) Encodes An Interleukin-8 Homolog (Vil-8): Characterization Of The Vil-8 Protein And A Vil-8 Deletion Mutant Mdv, Mark S. Parcells, Su-Fang Lin, Robert L. Dienglewicz, Vladimir Majerciak, Dan R. Robinson, Hua-Chien Chen, Zining Wu, George R. Dubyak, Peter Brunovskis, Henry D. Hunt Jun 2001

Marek's Disease Virus (Mdv) Encodes An Interleukin-8 Homolog (Vil-8): Characterization Of The Vil-8 Protein And A Vil-8 Deletion Mutant Mdv, Mark S. Parcells, Su-Fang Lin, Robert L. Dienglewicz, Vladimir Majerciak, Dan R. Robinson, Hua-Chien Chen, Zining Wu, George R. Dubyak, Peter Brunovskis, Henry D. Hunt

Dartmouth Scholarship

Chemokines induce chemotaxis, cell migration, and inflammatory responses. We report the identification of an interleukin-8 (IL-8) homolog, termed vIL-8, encoded within the genome of Marek's disease virus (MDV). The 134-amino-acid vIL-8 shares closest homology to mammalian and avian IL-8, molecules representing the prototype CXC chemokine. The gene for vIL-8 consists of three exons which map to the BamHI-L fragment within the repeats flanking the unique long region of the MDV genome. A 0.7-kb transcript encoding vIL-8 was detected in an n-butyrate-treated, MDV-transformed T-lymphoblastoid cell line, MSB-1. This induction is essentially abolished by cycloheximide and herpesvirus DNA polymerase inhibitor phosphonoacetate, indicating …

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Characterization Of The Cd154-Positive And Cd40-Positive Cellular Subsets Required For Pathogenesis In Retrovirus-Induced Murine Immunodeficiency, Kathy A. Green, Randolph J. Noelle, Brigit G. Durell, William R. Green Apr 2001

Characterization Of The Cd154-Positive And Cd40-Positive Cellular Subsets Required For Pathogenesis In Retrovirus-Induced Murine Immunodeficiency, Kathy A. Green, Randolph J. Noelle, Brigit G. Durell, William R. Green

Dartmouth Scholarship

Genetically susceptible C57BL/6 (B6) mice that are infected with the LP-BM5 isolate of murine retroviruses develop profound splenomegaly, lymphadenopathy, hypergammaglobulinemia, terminal B-cell lymphomas, and an immunodeficiency state bearing many similarities to the pathologies seen in AIDS. Because of these similarities, this syndrome has been called murine AIDS (MAIDS). We have previously shown that CD154 (CD40 ligand)-CD40 molecular interactions are required both for the initiation and progression of MAIDS. Thus, in vivo anti-CD154 monoclonal antibody (MAb) treatment inhibited MAIDS symptoms in LP-BM5-infected wild-type mice when either a short course of anti-CD154 MAb treatment was started on the day of infection or …

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Central Chemosensitivity, Sleep, And Wakefulness, E. E. Nattie, A Li Jan 2001

Central Chemosensitivity, Sleep, And Wakefulness, E. E. Nattie, A Li

Dartmouth Scholarship

No abstract provided.

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Ups And Downs Of Mucosal Cellular Immunity Against Protozoan Parasites, Lloyd H. Kasper, Dominique Buzoni-Gatel Jan 2001

Ups And Downs Of Mucosal Cellular Immunity Against Protozoan Parasites, Lloyd H. Kasper, Dominique Buzoni-Gatel

Dartmouth Scholarship

No abstract provided.

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Genomic Structure Of Murine Mitochondrial Dna Polymerase-Gamma., Justin L. Mott, Grace Denniger, Steve J. Zullo, H. Peter Zassenhaus Oct 2000

Genomic Structure Of Murine Mitochondrial Dna Polymerase-Gamma., Justin L. Mott, Grace Denniger, Steve J. Zullo, H. Peter Zassenhaus

Journal Articles: Biochemistry & Molecular Biology

We have sequenced a genomic clone of the gene encoding the mouse mitochondrial DNA polymerase. The gene consists of 23 exons, which span approximately 13.2 kb, with exons ranging in size from 53 to 768 bp. All intron-exon boundaries conform to the GT-AG rule. By comparison with the human genomic sequence, we found remarkable conservation of the gene structure; the intron-exon borders are in almost identical locations for the 22 introns. The 5' upstream region contains approximately 300 bp of homology between the mouse and human sequences that presumably contain the promoter element. This region lacks any obvious TATA domain …

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Prolonged Cyclooxygenase-2 Induction In Neurons And Glia Following Traumatic Brain Injury In The Rat, Kenneth I. Strauss, Mary F. Barbe, Renee Marshall Demarest, Ramesh Raghupathi, Samir Mehta, Raj K. Narayan Aug 2000

Prolonged Cyclooxygenase-2 Induction In Neurons And Glia Following Traumatic Brain Injury In The Rat, Kenneth I. Strauss, Mary F. Barbe, Renee Marshall Demarest, Ramesh Raghupathi, Samir Mehta, Raj K. Narayan

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Cyclooxygenase-2 (COX2) is a primary inflammatory mediator that converts arachidonic acid into precursors of vasoactive prostaglandins, producing reactive oxygen species in the process. Under normal conditions COX2 is not detectable, except at low abundance in the brain. This study demonstrates a distinctive pattern of COX2 increases in the brain over time following traumatic brain injury (TBI). Quantitative lysate ribonuclease protection assays indicate acute and sustained increases in COX2 mRNA in two rat models of TBI. In the lateral fluid percussion model, COX2 mRNA is significantly elevated (>twofold, p < 0.05, Dunnett) at 1 day postinjury in the injured cortex and bilaterally in the hippocampus, compared to sham-injured controls. In the lateral cortical impact model (LCI), COX2 mRNA peaks around 6 h postinjury in the ipsilateral cerebral cortex (fivefold induction, p < 0.05, Dunnett) and in the ipsilateral and contralateral hippocampus (two- and six-fold induction, respectively, p < 0.05, Dunnett). Increases are sustained out to 3 days postinjury in the injured cortex in both models. Further analyses use the LCI model to evaluate COX2 induction. Immunoblot analyses confirm increased levels of COX2 protein in the cortex and hippocampus. Profound increases in COX2 protein are observed in the cortex at 1-3 days, that return to sham levels by 7 days postinjury (p < 0.05, Dunnett). The cellular pattern of COX2 induction following TBI has been characterized using immunohistochemistry. COX2-immunoreactivity (-ir) rises acutely (cell numbers and intensity) and remains elevated for several days following TBI. Increases in COX2-ir colocalize with neurons (MAP2-ir) and glia (GFAP-ir). Increases in COX2-ir are observed in cerebral cortex and hippocampus, ipsilateral and contralateral to injury as early as 2 h postinjury. Neurons in the ipsilateral parietal, perirhinal and piriform cortex become intensely COX2-ir from 2 h to at least 3 days postinjury. In agreement with the mRNA and immunoblot results, COX2-ir appears greatest in the contralateral hippocampus. Hippocampal COX2-ir progresses from the pyramidal cell layer of the CA1 and CA2 region at 2 h, to the CA3 pyramidal cells and dentate polymorphic and granule cell layers by 24 h postinjury. These increases are distinct from those observed following inflammatory challenge, and correspond to brain areas previously identified with the neurological and cognitive deficits associated with TBI. While COX2 induction following TBI may result in selective beneficial responses, chronic COX2 production may contribute to free radical mediated cellular damage, vascular dysfunction, and alterations in cellular metabolism. These may cause secondary injuries to the brain that promote neuropathology and worsen behavioral outcome.

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Inhibition Of Antiviral Ctl Responses By Virus-Infected Cells: Line Item Veto (Cells) Revisited, Robert F. Rich, William R. Green Apr 2000

Inhibition Of Antiviral Ctl Responses By Virus-Infected Cells: Line Item Veto (Cells) Revisited, Robert F. Rich, William R. Green

Dartmouth Scholarship

No abstract provided.

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Anti-Gag Cytolytic T Lymphocytes Specific For An Alternative Translational Reading Frame-Derived Epitope And Resistance Versus Susceptibility To Retrovirus-Induced Murine Aids In F1 Mice, Shawn-Marie Mayrand, Patricia A. Healy, Bruce E. Torbett, William R. Green Apr 2000

Anti-Gag Cytolytic T Lymphocytes Specific For An Alternative Translational Reading Frame-Derived Epitope And Resistance Versus Susceptibility To Retrovirus-Induced Murine Aids In F1 Mice, Shawn-Marie Mayrand, Patricia A. Healy, Bruce E. Torbett, William R. Green

Dartmouth Scholarship

Murine AIDS (MAIDS) develops in susceptible mouse strains after infection with the LP-BM5 murine leukemia virus complex that contains causative defective, and ecotropic helper, retroviruses. We previously demonstrated that the MAIDSresistant H-2d strains BALB/cByJ and C57BL/KsJ generate MHC class I (Kd ) restricted virus-specific CD81 cytolytic T lymphocytes (CTLs) that lyse cells expressing either defective or ecotropic gag proteins. In contrast, the congenic BALB.B and closely related C57BL/6J MAIDS-susceptible H-2b strains were unable to serve as a source of gag-specific CTLs (Schwarz and Green, 1994), suggesting that anti-gag CTLs might provide a basis for resistance to MAIDS. Although its susceptibility …

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Membrane Cholesterol Content Modulates Activation Of Volume-Regulated Anion Current In Bovine Endothelial Cells., I Levitan, A E Christian, T N Tulenko, G H Rothblat Apr 2000

Membrane Cholesterol Content Modulates Activation Of Volume-Regulated Anion Current In Bovine Endothelial Cells., I Levitan, A E Christian, T N Tulenko, G H Rothblat

Department of Biochemistry and Molecular Biology Faculty Papers

Activation of volume-regulated anion current (VRAC) plays a key role in the maintenance of cellular volume homeostasis. The mechanisms, however, that regulate VRAC activity are not fully understood. We have examined whether VRAC activation is modulated by the cholesterol content of the membrane bilayer. The cholesterol content of bovine aortic endothelial cells was increased by two independent methods: (a) exposure to a methyl-beta-cyclodextrin saturated with cholesterol, or (b) exposure to cholesterol-enriched lipid dispersions. Enrichment of bovine aortic endothelial cells with cholesterol resulted in a suppression of VRAC activation in response to a mild osmotic gradient, but not to a strong …

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