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Full-Text Articles in Medicine and Health Sciences

The Kidney-Specific Wnk1 Isoform Is Induced By Aldosterone And Stimulates Epithelial Sodium Channel-Mediated Na+ Transport, Anikó Naray-Fejes-Toth, Peter M. Snyder, Géza Fejes-Toth Dec 2004

The Kidney-Specific Wnk1 Isoform Is Induced By Aldosterone And Stimulates Epithelial Sodium Channel-Mediated Na+ Transport, Anikó Naray-Fejes-Toth, Peter M. Snyder, Géza Fejes-Toth

Dartmouth Scholarship

WNK1 belongs to a unique family of Ser/Thr kinases that have been implicated in the control of blood pressure. Intronic deletions in the WNK1 gene result in its overexpression and lead to pseudohypoaldosteronism type II, a disease with salt-sensitive hypertension and hyperkalemia. How overexpression of WNK1 leads to Na+ retention and hypertension is not entirely clear. Similarly, there is no information on the hormonal regulation of expression of WNK kinases. There are two main WNK1 transcripts expressed in the kidney: the originally described “long” WNK1 and a shorter transcript that is specifically expressed in the kidney (KS-WNK1). The goal …


A Vibrio Cholerae Classical Tcpa Amino Acid Sequence Induces Protective Antibody That Binds An Area Hypothesized To Be Important For Toxin-Coregulated Pilus Structure, Ronald K. Taylor, Thomas J. Kirn, Michael D. Meeks, Terri K. Wade, William F. Wade Oct 2004

A Vibrio Cholerae Classical Tcpa Amino Acid Sequence Induces Protective Antibody That Binds An Area Hypothesized To Be Important For Toxin-Coregulated Pilus Structure, Ronald K. Taylor, Thomas J. Kirn, Michael D. Meeks, Terri K. Wade, William F. Wade

Dartmouth Scholarship

Vibrio cholerae is a gram-negative bacterium that has been associated with cholera pandemics since the early 1800s. Whole-cell, killed, and live-attenuated oral cholera vaccines are in use. We and others have focused on the development of a subunit cholera vaccine that features standardized epitopes from various V. cholerae macromolecules that are known to induce protective antibody responses. TcpA protein is assembled into toxin-coregulated pilus (TCP), a type IVb pilus required for V. cholerae colonization, and thus is a strong candidate for a cholera subunit vaccine. Polypeptides (24 to 26 amino acids) in TcpA that can induce protective antibody responses have …


Cd4+ T Cells In The Pathogenesis Of Murine Ocular Toxoplasmosis, Fangli Lu, Shiguang Huang, Lloyd H. Kasper Sep 2004

Cd4+ T Cells In The Pathogenesis Of Murine Ocular Toxoplasmosis, Fangli Lu, Shiguang Huang, Lloyd H. Kasper

Dartmouth Scholarship

The role of CD4+ T cells in the pathogenesis of ocular toxoplasmosis was investigated in murine models utilizing inbred C57BL/6 mice deficient either in CD4+, CD8+, or B cells (μMT). Severe necrosis and inflammation with replicating parasites were observed in the eyes of control mice after primary ocular infection, and near-normal histology with few tachyzoites was observed in the eyes of mice immunized intraperitoneally with the avirulent ts-4 strain followed by intraocular challenge with the RH strain of Toxoplasma gondii. In contrast, mild inflammation without evidence of necrosis associated with increased parasite burdens were …


A Novel Triterpenoid Induces Transforming Growth Factor Β Production By Intraepithelial Lymphocytes To Prevent Ileitis, Laurie A. Minns, Dominique Buzoni-Gatel, Kenneth H. Ely, Nicolas Rachinel, Souphalone Luangsay, Lloyd H. Kasper Jul 2004

A Novel Triterpenoid Induces Transforming Growth Factor Β Production By Intraepithelial Lymphocytes To Prevent Ileitis, Laurie A. Minns, Dominique Buzoni-Gatel, Kenneth H. Ely, Nicolas Rachinel, Souphalone Luangsay, Lloyd H. Kasper

Dartmouth Scholarship

The loss of homeostasis is a hallmark of inflammatory bowel disease. Oral infection of susceptible mice with Toxoplasma gondii results in an acute lethal ileitis characterized by increased interferon γ, tumor necrosis factor α, and inducible nitric oxide synthase; homeostasis results from transforming growth factor β production by intraepithelial lymphocytes. The synthetic oleanane triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) is a potent anti-inflammatory molecule previously shown in vitro to suppress the de novo synthesis of inducible nitric oxide synthase and to induce the transcription and activation of genes from the transforming growth factor β signaling pathway. We evaluated the immune response in …


Endogenous No Regulates Superoxide Production At Low Oxygen Concentrations By Modifying The Redox State Of Cytochrome C Oxidase, Miriam Palacios-Callender, Marisol Quintero, Veronica S. Hollis, Roger J. Springett, Salvador Moncada May 2004

Endogenous No Regulates Superoxide Production At Low Oxygen Concentrations By Modifying The Redox State Of Cytochrome C Oxidase, Miriam Palacios-Callender, Marisol Quintero, Veronica S. Hollis, Roger J. Springett, Salvador Moncada

Dartmouth Scholarship

We have investigated in whole cells whether, at low oxygen concentrations ([O(2)]), endogenous nitric oxide (NO) modulates the redox state of the mitochondrial electron transport chain (ETC), and whether such an action has any signaling consequences. Using a polarographic-and-spectroscopic-coupled system, we monitored redox changes in the ETC cytochromes b(H), cc(1), and aa(3) during cellular respiration. The rate of O(2) consumption (VO(2)) remained constant until [O(2)] fell below 15 microM, whereas the onset of reduction of cytochromes aa(3), part of the terminal ETC enzyme cytochrome c oxidase, occurred at approximately 50 microM O(2). Incubation of the cells with an inhibitor of …


Combined Tlr And Cd40 Triggering Induces Potent Cd8+ T Cell Expansion With Variable Dependence On Type I Ifn, Cory L. Ahonen, Christie L. Doxsee, Sean M. M. Mcgurran, Tony R. Riter, William F. Wade, Richard J. Barth, John P. Vasilakos, Randolph J. Noelle, Ross M. Kedl Mar 2004

Combined Tlr And Cd40 Triggering Induces Potent Cd8+ T Cell Expansion With Variable Dependence On Type I Ifn, Cory L. Ahonen, Christie L. Doxsee, Sean M. M. Mcgurran, Tony R. Riter, William F. Wade, Richard J. Barth, John P. Vasilakos, Randolph J. Noelle, Ross M. Kedl

Dartmouth Scholarship

Toll-like receptors are important in the activation of innate immunity, and CD40 is a molecule critical for many T and B cell responses. Whereas agonists for either pathway have been used as vaccine adjuvants, we show that a combination of Toll-like receptor (TLR)7 and CD40 agonists synergize to stimulate CD8+ T cell responses 10–20-fold greater than the use of either agonist alone. Antigen-specific CD8+ T cells elicited from combination CD40/TLR7 treatment demonstrated both lytic activities and interferon (IFN)γ production and an enhanced secondary response to antigenic challenge. Agonists for TLRs 2/6, 3, 4, and 9 also synergized with …


The Tumor Suppressor Lkb1 Kinase Directly Activates Amp-Activated Kinase And Regulates Apoptosis In Response To Energy Stress, Reuben J. Shaw, Monica Kosmatka, Nabeel Bardeesy, Rebecca L. Hurley, Lee A. Witters, Ronald A. Depinho, Lewis C. Cantley Mar 2004

The Tumor Suppressor Lkb1 Kinase Directly Activates Amp-Activated Kinase And Regulates Apoptosis In Response To Energy Stress, Reuben J. Shaw, Monica Kosmatka, Nabeel Bardeesy, Rebecca L. Hurley, Lee A. Witters, Ronald A. Depinho, Lewis C. Cantley

Dartmouth Scholarship

AMP-activated protein kinase (AMPK) is a highly conserved sensor of cellular energy status found in all eukaryotic cells. AMPK is activated by stimuli that increase the cellular AMP/ATP ratio. Essential to activation of AMPK is its phosphorylation at Thr-172 by an upstream kinase, AMPKK, whose identity in mammalian cells has remained elusive. Here we present biochemical and genetic evidence indicating that the LKB1 serine/threonine kinase, the gene inactivated in the Peutz-Jeghers familial cancer syndrome, is the dominant regulator of AMPK activation in several mammalian cell types. We show that LKB1 directly phosphorylates Thr-172 of AMPKalpha in vitro and activates its …


Hearing Loss And Retarded Cochlear Development In Mice Lacking Type 2 Iodothyronine Deiodinase, Lily Ng, Richard J. Goodyear, Chad A. Woods, Mark J. Schneider Mar 2004

Hearing Loss And Retarded Cochlear Development In Mice Lacking Type 2 Iodothyronine Deiodinase, Lily Ng, Richard J. Goodyear, Chad A. Woods, Mark J. Schneider

Dartmouth Scholarship

The later stages of cochlear differentiation and the developmental onset of hearing require thyroid hormone. Although thyroid hormone receptors (TRs) are a prerequisite for this process, it is likely that other factors modify TR activity during cochlear development. The mouse cochlea expresses type 2 deiodinase (D2), an enzyme that converts thyroxine, the main form of thyroid hormone in the circulation, into 3,5,3'-triiodothyronine (T3) the major ligand for TRs. Here, we show that D2-deficient mice have circulating thyroid hormone levels that would normally be adequate to allow hearing to develop but they exhibit an auditory phenotype similar to that caused by …


Immune Responses Of Different Mouse Strains After Challenge With Equivalent Lethal Doses Of Toxoplasma Gondii, Y. H. Lee, L. H. Kasper Mar 2004

Immune Responses Of Different Mouse Strains After Challenge With Equivalent Lethal Doses Of Toxoplasma Gondii, Y. H. Lee, L. H. Kasper

Dartmouth Scholarship

Most immunological studies that utilize different strains of inbred mice following T. gondii infection fail to compensate for differences in host susceptibility to the size of the parasite innoculum. To address this concern, susceptible C57BL/6 and resistant CBA/J mice were orally infected with either an equivalent 50 % lethal dose (LD50) of brain cysts of the 76K strain of T. gondii (15 cysts in C57BL/6, 400 cysts in CBA/J) or the same dose of parasites in each mouse strain. C57BL/6 mice receiving 400 cysts (LD50 of CBA/J mice) died post infection, whereas CBA/J mice that received 15 …


Bcma Is Essential For The Survival Of Long-Lived Bone Marrow Plasma Cells, Brian P. O'Connor, Vanitha S. Raman, Loren D. Erickson, W. James Cook, Lehn K. Weaver, Cory Ahonen, Ling-Li Lin, George Mantchev, Richard J. Bram, Randolph J. Noelle Jan 2004

Bcma Is Essential For The Survival Of Long-Lived Bone Marrow Plasma Cells, Brian P. O'Connor, Vanitha S. Raman, Loren D. Erickson, W. James Cook, Lehn K. Weaver, Cory Ahonen, Ling-Li Lin, George Mantchev, Richard J. Bram, Randolph J. Noelle

Dartmouth Scholarship

Long-lived humoral immunity is manifested by the ability of bone marrow plasma cells (PCs) to survive for extended periods of time. Recent studies have underscored the importance of BLyS and APRIL as factors that can support the survival of B lineage lymphocytes. We show that BLyS can sustain PC survival in vitro, and this survival can be further enhanced by inter- leukin 6. Selective up-regulation of Mcl-1 in PCs by BLyS suggests that this 􏰀-apoptotic gene product may play an important role in PC survival. Blockade of BLyS, via transmembrane activator and cyclophilin ligand interactor–immunoglobulin treatment, inhibited PC survival in …


Slbp Is Associated With Histone Mrna On Polyribosomes As A Component Of The Histone Mrnp, Michael L. Whitfield, Handan Kaygun, Judith A. Erkmann, W. H. Davin Townley-Tilson, Zbig Dominski, William F. Marzluff Jan 2004

Slbp Is Associated With Histone Mrna On Polyribosomes As A Component Of The Histone Mrnp, Michael L. Whitfield, Handan Kaygun, Judith A. Erkmann, W. H. Davin Townley-Tilson, Zbig Dominski, William F. Marzluff

Dartmouth Scholarship

The stem–loop binding protein (SLBP) binds the 3′ end of histone mRNA and is present both in nucleus, and in the cytoplasm on the polyribosomes. SLBP participates in the processing of the histone pre-mRNA and in translation of the mature message. Histone mRNAs are rapidly degraded when cells are treated with inhibitors of DNA replication and are stabilized by inhibitors of translation, resulting in an increase in histone mRNA levels. Here, we show that SLBP is a component of the histone messenger ribonucleoprotein particle (mRNP). Histone mRNA from polyribosomes is immunoprecipitated with anti-SLBP. Most of the SLBP in cycloheximide-treated cells …


Inactivation Of A Bacterial Virulence Pheromone By Phagocyte-Derived Oxidants: New Role For The Nadph Oxidase In Host Defense, Jacob M. Rothfork, Graham S. Timmins, Michael N. Harris, Xian Chen, Aldons J. Lusis, Michael Otto, Ambrose L. Cheung, Hattie D. Gresham Jan 2004

Inactivation Of A Bacterial Virulence Pheromone By Phagocyte-Derived Oxidants: New Role For The Nadph Oxidase In Host Defense, Jacob M. Rothfork, Graham S. Timmins, Michael N. Harris, Xian Chen, Aldons J. Lusis, Michael Otto, Ambrose L. Cheung, Hattie D. Gresham

Dartmouth Scholarship

Quorum sensing triggers virulence factor expression in medically important bacterial pathogens in response to a density-dependent increase in one or more autoinducing pheromones. Here, we show that phagocyte-derived oxidants target these autoinducers for inactivation as an innate defense mechanism of the host. In a skin infection model, expression of phagocyte NADPH oxidase, myeloperoxidase, or inducible nitric oxide synthase was critical for defense against a quorum-sensing pathogen, Staphylococcus aureus, but not for defense against a quorum sensing-deficient mutant. A virulence-inducing peptide of S. aureus was inactivated in vitro and in vivo by reactive oxygen and nitrogen intermediates, including HOCl and ONOO(-). …