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Jakosky BM, Grebowsky JM, Luhmann JG, Connerney J, Eparvier F, Ergun R, Halekas J, Larson D, Mahaffy P, McFadden J, Mitchell DF, Schneider N, Zurek R, Bougher S, Brain D, Ma YJ, Mazelle C, Andersson L, Andrews D, Baird D, Baker D, Bell JM, Benna M, Chaffin M, Chamberlin P, Chaufray YY, Clarke J, Collinson G, Combi M, Crary F, Cravens T, Crismani M, Curry S, Curtis D, Deighan J, Delory G, Dewey R, DiBraccio G, Dong C, Dong Y, Dunn P, Elrod M, England S, Eriksson A, Espley J, Evans S, Fang X, Fillingim M, Fortier K, Fowler CM, Fox J, Gröller H, Guzewich S, Hara T, Harada Y, Holsclaw G, Jain SK, Jolitz R, Leblanc F, Lee CO, Lee Y, Lefevre F, Lillis R, Livi R, Lo D, Mayyasi M, McClintock W, McEnulty T, Modolo R, Montmessin F, Morooka M, Nagy A, Olsen K, Peterson W, Rahmati A, Ruhunusiri S, Russell CT, Sakai S, Sauvaud JA, Seki K, Steckiewicz M, Stevens M, Stewart AIF, Stiepen A, Stone S, Tenishev V, Thiemann E, Tolson R, Toublanc D, Vogt M, Weber T, Withers P, Woods T, Yelle R. MAVEN observations of the response of Mars to an interplanetary coronal mass ejection. Science 2015; 350:aad0210. [PMID: 26542576 DOI: 10.1126/science.aad0210] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.
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Affiliation(s)
| | - J M Grebowsky
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - J G Luhmann
- University of California at Berkeley, Berkeley, CA, USA
| | - J Connerney
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - F Eparvier
- University of Colorado, Boulder, CO, USA
| | - R Ergun
- University of Colorado, Boulder, CO, USA
| | - J Halekas
- University of Iowa, Iowa City, IA, USA
| | - D Larson
- University of California at Berkeley, Berkeley, CA, USA
| | - P Mahaffy
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - J McFadden
- University of California at Berkeley, Berkeley, CA, USA
| | - D F Mitchell
- University of California at Berkeley, Berkeley, CA, USA
| | | | - R Zurek
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - S Bougher
- University of Michigan, Ann Arbor, MI, USA
| | - D Brain
- University of Colorado, Boulder, CO, USA
| | - Y J Ma
- University of California at Los Angeles, Los Angeles, CA, USA
| | - C Mazelle
- CNRS-Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. University Paul Sabatier, Toulouse, France
| | | | - D Andrews
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - D Baird
- NASA/Johnson Space Center, Houston, TX, USA
| | - D Baker
- University of Colorado, Boulder, CO, USA
| | - J M Bell
- National Institute of Aerospace, Hampton, VA, USA
| | - M Benna
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Chaffin
- University of Colorado, Boulder, CO, USA
| | - P Chamberlin
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - Y-Y Chaufray
- Laboratoire atmosphères, milieux et observations spatiales (LATMOS)-CNRS, Paris, France
| | - J Clarke
- Boston University, Boston, MA, USA
| | - G Collinson
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Combi
- University of Michigan, Ann Arbor, MI, USA
| | - F Crary
- University of Colorado, Boulder, CO, USA
| | - T Cravens
- University of Kansas, Lawrence, KS, USA
| | - M Crismani
- University of Colorado, Boulder, CO, USA
| | - S Curry
- University of California at Berkeley, Berkeley, CA, USA
| | - D Curtis
- University of California at Berkeley, Berkeley, CA, USA
| | - J Deighan
- University of Colorado, Boulder, CO, USA
| | - G Delory
- University of California at Berkeley, Berkeley, CA, USA
| | - R Dewey
- University of Colorado, Boulder, CO, USA
| | - G DiBraccio
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - C Dong
- University of Michigan, Ann Arbor, MI, USA
| | - Y Dong
- University of Colorado, Boulder, CO, USA
| | - P Dunn
- University of California at Berkeley, Berkeley, CA, USA
| | - M Elrod
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - S England
- University of California at Berkeley, Berkeley, CA, USA
| | - A Eriksson
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - J Espley
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - S Evans
- Computational Physics, Inc., Boulder, CO, USA
| | - X Fang
- University of Colorado, Boulder, CO, USA
| | - M Fillingim
- University of California at Berkeley, Berkeley, CA, USA
| | - K Fortier
- University of Colorado, Boulder, CO, USA
| | - C M Fowler
- University of Colorado, Boulder, CO, USA
| | - J Fox
- Wright State University, Dayton, OH, USA
| | - H Gröller
- University of Arizona, Tucson, AZ, USA
| | - S Guzewich
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - T Hara
- University of California at Berkeley, Berkeley, CA, USA
| | - Y Harada
- University of California at Berkeley, Berkeley, CA, USA
| | - G Holsclaw
- University of Colorado, Boulder, CO, USA
| | - S K Jain
- University of Colorado, Boulder, CO, USA
| | - R Jolitz
- University of California at Berkeley, Berkeley, CA, USA
| | - F Leblanc
- Laboratoire atmosphères, milieux et observations spatiales (LATMOS)-CNRS, Paris, France
| | - C O Lee
- University of California at Berkeley, Berkeley, CA, USA
| | - Y Lee
- University of Michigan, Ann Arbor, MI, USA
| | - F Lefevre
- Laboratoire atmosphères, milieux et observations spatiales (LATMOS)-CNRS, Paris, France
| | - R Lillis
- University of California at Berkeley, Berkeley, CA, USA
| | - R Livi
- University of California at Berkeley, Berkeley, CA, USA
| | - D Lo
- University of Arizona, Tucson, AZ, USA
| | | | | | - T McEnulty
- University of Colorado, Boulder, CO, USA
| | - R Modolo
- Laboratoire atmosphères, milieux et observations spatiales (LATMOS)-CNRS, Paris, France
| | - F Montmessin
- Laboratoire atmosphères, milieux et observations spatiales (LATMOS)-CNRS, Paris, France
| | - M Morooka
- University of Colorado, Boulder, CO, USA
| | - A Nagy
- University of Michigan, Ann Arbor, MI, USA
| | - K Olsen
- University of Michigan, Ann Arbor, MI, USA
| | - W Peterson
- University of Colorado, Boulder, CO, USA
| | - A Rahmati
- University of Kansas, Lawrence, KS, USA
| | | | - C T Russell
- University of California at Los Angeles, Los Angeles, CA, USA
| | - S Sakai
- University of Kansas, Lawrence, KS, USA
| | - J-A Sauvaud
- CNRS-Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. University Paul Sabatier, Toulouse, France
| | - K Seki
- Nagoya University, Nagoya, Japan
| | - M Steckiewicz
- CNRS-Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. University Paul Sabatier, Toulouse, France
| | - M Stevens
- Naval Research Laboratory, Washington, DC, USA
| | | | - A Stiepen
- University of Colorado, Boulder, CO, USA
| | - S Stone
- University of Arizona, Tucson, AZ, USA
| | - V Tenishev
- University of Michigan, Ann Arbor, MI, USA
| | - E Thiemann
- University of Colorado, Boulder, CO, USA
| | - R Tolson
- North Carolina State University, Raleigh, NC, USA
| | - D Toublanc
- CNRS-Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. University Paul Sabatier, Toulouse, France
| | - M Vogt
- Boston University, Boston, MA, USA
| | - T Weber
- University of Colorado, Boulder, CO, USA
| | | | - T Woods
- University of Colorado, Boulder, CO, USA
| | - R Yelle
- University of Arizona, Tucson, AZ, USA
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Bougher S, Jakosky B, Halekas J, Grebowsky J, Luhmann J, Mahaffy P, Connerney J, Eparvier F, Ergun R, Larson D, McFadden J, Mitchell D, Schneider N, Zurek R, Mazelle C, Andersson L, Andrews D, Baird D, Baker DN, Bell JM, Benna M, Brain D, Chaffin M, Chamberlin P, Chaufray JY, Clarke J, Collinson G, Combi M, Crary F, Cravens T, Crismani M, Curry S, Curtis D, Deighan J, Delory G, Dewey R, DiBraccio G, Dong C, Dong Y, Dunn P, Elrod M, England S, Eriksson A, Espley J, Evans S, Fang X, Fillingim M, Fortier K, Fowler CM, Fox J, Gröller H, Guzewich S, Hara T, Harada Y, Holsclaw G, Jain SK, Jolitz R, Leblanc F, Lee CO, Lee Y, Lefevre F, Lillis R, Livi R, Lo D, Ma Y, Mayyasi M, McClintock W, McEnulty T, Modolo R, Montmessin F, Morooka M, Nagy A, Olsen K, Peterson W, Rahmati A, Ruhunusiri S, Russell CT, Sakai S, Sauvaud JA, Seki K, Steckiewicz M, Stevens M, Stewart AIF, Stiepen A, Stone S, Tenishev V, Thiemann E, Tolson R, Toublanc D, Vogt M, Weber T, Withers P, Woods T, Yelle R. Early MAVEN Deep Dip campaign reveals thermosphere and ionosphere variability. Science 2015; 350:aad0459. [PMID: 26542579 DOI: 10.1126/science.aad0459] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements of martian thermosphere and ionosphere composition, structure, and variability at altitudes down to ~130 kilometers in the subsolar region. This altitude range contains the diffusively separated upper atmosphere just above the well-mixed atmosphere, the layer of peak extreme ultraviolet heating and primary reservoir for atmospheric escape. In situ measurements of the upper atmosphere reveal previously unmeasured populations of neutral and charged particles, the homopause altitude at approximately 130 kilometers, and an unexpected level of variability both on an orbit-to-orbit basis and within individual orbits. These observations help constrain volatile escape processes controlled by thermosphere and ionosphere structure and variability.
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Affiliation(s)
- S Bougher
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA.
| | - B Jakosky
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - J Halekas
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - J Grebowsky
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - J Luhmann
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - P Mahaffy
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - J Connerney
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - F Eparvier
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - R Ergun
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - D Larson
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - J McFadden
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - D Mitchell
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - N Schneider
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - R Zurek
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - C Mazelle
- CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France. University Paul Sabatier, Toulouse, France
| | - L Andersson
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - D Andrews
- Swedish Institute of Space Physics, Kiruna, Sweden
| | - D Baird
- NASA/Johnson Space Center, Houston, TX, USA
| | - D N Baker
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - J M Bell
- National Institute of Aerospace, Hampton, VA, USA
| | - M Benna
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - D Brain
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - M Chaffin
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - P Chamberlin
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - J-Y Chaufray
- Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
| | - J Clarke
- Department of Astronomy, Boston University, Boston, MA, USA
| | - G Collinson
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Combi
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA
| | - F Crary
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - T Cravens
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - M Crismani
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - S Curry
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - D Curtis
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - J Deighan
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - G Delory
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - R Dewey
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - G DiBraccio
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - C Dong
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA
| | - Y Dong
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - P Dunn
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - M Elrod
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - S England
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - A Eriksson
- Swedish Institute of Space Physics, Kiruna, Sweden
| | - J Espley
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - S Evans
- Computational Physics, Springfield, VA, USA
| | - X Fang
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - M Fillingim
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - K Fortier
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - C M Fowler
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - J Fox
- Department of Physics, Wright State University, Fairborn, OH, USA
| | - H Gröller
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - S Guzewich
- NASA/Goddard Space Flight Center, Greenbelt, MD, USA
| | - T Hara
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - Y Harada
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - G Holsclaw
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - S K Jain
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - R Jolitz
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - F Leblanc
- Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
| | - C O Lee
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - Y Lee
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA
| | - F Lefevre
- Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
| | - R Lillis
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - R Livi
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - D Lo
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - Y Ma
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA, USA
| | - M Mayyasi
- Department of Astronomy, Boston University, Boston, MA, USA
| | - W McClintock
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - T McEnulty
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - R Modolo
- Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
| | - F Montmessin
- Laboratoire Atmosphères, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France
| | - M Morooka
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - A Nagy
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA
| | - K Olsen
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA
| | - W Peterson
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - A Rahmati
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - S Ruhunusiri
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - C T Russell
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA, USA
| | - S Sakai
- Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
| | - J-A Sauvaud
- CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France. University Paul Sabatier, Toulouse, France
| | - K Seki
- Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi, Japan
| | - M Steckiewicz
- CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France. University Paul Sabatier, Toulouse, France
| | - M Stevens
- Naval Research Laboratory, Washington, DC, USA
| | - A I F Stewart
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - A Stiepen
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - S Stone
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - V Tenishev
- CLaSP Department, University of Michigan, Ann Arbor, MI, USA
| | - E Thiemann
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - R Tolson
- National Institute of Aerospace, Hampton, VA, USA
| | - D Toublanc
- CNRS/Institut de Recherche en Astrophysique et Planétologie, Toulouse, France. University Paul Sabatier, Toulouse, France
| | - M Vogt
- Department of Astronomy, Boston University, Boston, MA, USA
| | - T Weber
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - P Withers
- Department of Astronomy, Boston University, Boston, MA, USA
| | - T Woods
- Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA
| | - R Yelle
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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Castanheira M, Bell JM, Turnidge JD, Mendes RE, Jones RN. Dissemination and genetic context analysis of bla(VIM-6) among Pseudomonas aeruginosa isolates in Asian-Pacific Nations. Clin Microbiol Infect 2009; 16:186-9. [PMID: 19673963 DOI: 10.1111/j.1469-0691.2009.02903.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
VIM-6, previously reported in two strains from Singapore recovered in 2000, was detected in 16 isolates collected in 2006 in India (12 isolates), Indonesia (two), Korea and the Philippines (one each). High genetic variability was observed among VIM-6-producing isolates (12 ribotypes and 11 pulsed-field gel electrophoresis types), but clones were observed in India and Indonesia; bla(VIM-6)-carrying integrons of 3.9 kb and 5 kb were detected, and two of five Indian hospitals yielded isolates with both integrons. These two integrons, bla(VIM-6) was located in the first position, followed by bla(OXA-10) and aacA4. The 5-kb integrons also harboured aadA1 and a 331-bp open reading frame encoding a putative efflux pump.
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Basselin M, Fox MA, Chang L, Bell JM, Greenstein D, Chen M, Murphy DL, Rapoport SI. Imaging elevated brain arachidonic acid signaling in unanesthetized serotonin transporter (5-HTT)-deficient mice. Neuropsychopharmacology 2009; 34:1695-709. [PMID: 19145225 PMCID: PMC2700347 DOI: 10.1038/npp.2008.227] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Certain polymorphisms reduce serotonin (5-HT) reuptake transporter (5-HTT) function and increase susceptibility to psychiatric disorders. Heterozygous (5-HTT(+/-))-deficient mice, models for humans with these polymorphisms, have elevated brain 5-HT concentrations and behavioral abnormalities. As postsynaptic 5-HT(2A/2C) receptors are coupled to cytosolic phospholipase A(2) (cPLA(2)), which releases arachidonic acid (AA) from membrane phospholipid, 5-HTT-deficient mice may have altered brain AA signaling and metabolism. To test this hypothesis, signaling was imaged as an AA incorporation coefficient k(*) in unanesthetized homozygous knockout (5-HTT(-/-)), 5-HTT(+/-) and wild-type (5-HTT(+/+)), mice following saline (baseline) or 1.5 mg/kg s.c. DOI, a partial 5-HT(2A/2C) receptor agonist. Enzyme activities, metabolite concentrations, and head-twitch responses to DOI were also measured. Baseline k(*) was widely elevated by 20-70% in brains of 5-HTT(+/-) and 5-HTT(-/-) compared to 5-HTT(+/+) mice. DOI increased k(*) in 5-HTT(+/+) mice, but decreased k(*) in 5-HTT-deficient mice. Brain cPLA(2) activity was elevated in 5-HTT-deficient mice; cyclooxygenase activity and prostaglandin E(2) and F(2alpha) and thromboxane B(2) concentrations were reduced. Head-twitch responses to DOI, although robust in 5-HTT(+/+) and 5-HTT(+/-) mice, were markedly fewer in 5-HTT(-/-) mice. Pretreatment with para-chlorophenylalanine, a 5-HT synthesis inhibitor, restored head twitches in 5-HTT(-/-) mice to levels in 5-HTT(+/+) mice. We propose that increased baseline values of k(*) in 5-HTT-deficient mice reflect tonic cPLA(2) stimulation through 5-HT(2A/2C) receptors occupied by excess 5-HT, and that reduced k(*) and head-twitch responses to DOI reflected displacement of receptor-bound 5-HT by DOI with a lower affinity. Increased baseline AA signaling in humans having polymorphisms with reduced 5-HTT function might be identified using positron emission tomography.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
| | - Meredith A. Fox
- Laboratory of Clinical Science, National Institute of Mental Health. National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lisa Chang
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jane M. Bell
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Dede Greenstein
- Child Psychiatry Branch, National Institute of Mental Health. National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mei Chen
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Dennis L. Murphy
- Laboratory of Clinical Science, National Institute of Mental Health. National Institutes of Health, Bethesda, MD, 20892, USA
| | - Stanley I. Rapoport
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
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Igarashi M, Kim H, Chang L, Ma K, Bell JM, Rapoport SI. Dietary n‐6 PUFA deprivation in adult rats increases docosahexaenoic acid metabolism and consumption by brain. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.lb417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Basselin M, Nguyen HN, Chang L, Bell JM, Rapoport SI. Acute but not chronic donepezil increases muscarinic receptor-mediated signaling via arachidonic acid in unanesthetized rats. J Alzheimers Dis 2009; 17:369-82. [PMID: 19363262 PMCID: PMC2790024 DOI: 10.3233/jad-2009-1058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Donepezil, an acetylcholinesterase (AChE) inhibitor used for treating Alzheimer's disease patients, is thought to act by increasing brain extracellular acetylcholine (ACh), and ACh binding to cholinergic receptors. Muscarinic receptors are coupled to cytosolic phospholipase A2 (cPLA2) activation and arachidonic acid (AA) release from synaptic membrane phospholipid. This activation can be imaged in rodents as an AA incorporation coefficient k*, using quantitative autoradiography. Acute and chronic effects of donepezil on the AA signal, k* for AA, were measured in 81 brain regions of unanesthetized rats. Twenty min after a single oral dose (3.0 mg/kg) of donepezil, k* was increased significantly in 37 brain regions, whereas k* did not differ from control 7 h afterwards or following chronic (21 days) of donepezil. Pretreatment with atropine prevented the 20-min increments in k* following donepezil. Donepezil also increased the brain ACh concentration and reduced brain AChE activity, but did not change cPLA2 activity, regardless of administration regimen. These results show that donepezil acutely increases the brain AA signal that is mediated by ACh acting at muscarinic receptors, but that this signal is rapidly desensitized despite continued elevated brain ACh concentration. In contrast, the AA signal in response to arecoline was not altered following donepezil.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Room 1S126, Bethesda, MD 20892, USA.
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Gao F, Kiesewetter D, Chang L, Ma K, Bell JM, Rapoport SI, Igarashi M. Whole-body synthesis-secretion rates of long-chain n-3 PUFAs from circulating unesterified alpha-linolenic acid in unanesthetized rats. J Lipid Res 2008; 50:749-58. [PMID: 19074373 DOI: 10.1194/jlr.d800056-jlr200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), long-chain n-3 PUFAs important for brain and heart function, can be obtained from dietary fish products or by liver synthesis from alpha-linolenic acid (alpha-LNA). Their daily human dietary requirements are not clear, and their liver synthesis rates in humans and nonhumans are unknown. We estimated whole-body (presumably liver) synthesis rates in unanesthetized rats by infusing [U-(13)C]alpha-LNA intravenously for 2 h and measuring labeled and unlabeled n-3 PUFA in arterial plasma using negative chemical ionization GC-MS. Newly synthesized esterified [(13)C]DHA, [(13)C]EPA, and [(13)C]docosapentaenoic acid (DPA) appeared in arterial plasma after 60 min of infusion, then their concentrations rose in an S-shaped manner. Esterified concentration x plasma volume data were fit with a sigmoidal equation, whose peak first derivatives provided synthesis rates of unlabeled EPA, DPA, and DHA equal to 8.40, 6.27, and 9.84 mumol/day, respectively. The DHA synthesis rate exceeded the published daily rat brain DHA consumption rate by 30-fold, suggesting that liver synthesis from alpha-LNA could maintain brain DHA homeostasis were DHA absent from the diet. This stable isotope infusion method could be used to quantify whole-body DHA synthesis rates in human subjects.
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Affiliation(s)
- Fei Gao
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
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8
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Igarashi M, Gao F, Kim HW, Ma K, Bell JM, Rapoport SI. Dietary n-6 PUFA deprivation for 15 weeks reduces arachidonic acid concentrations while increasing n-3 PUFA concentrations in organs of post-weaning male rats. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1791:132-9. [PMID: 19073280 DOI: 10.1016/j.bbalip.2008.11.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 10/23/2008] [Accepted: 11/17/2008] [Indexed: 11/26/2022]
Abstract
Few studies have examined effects of feeding animals a diet deficient in n-6 polyunsaturated fatty acids (PUFAs) but with an adequate amount of n-3 PUFAs. To do this, we fed post-weaning male rats a control n-6 and n-3 PUFA adequate diet and an n-6 deficient diet for 15 weeks, and measured stable lipid and fatty acid concentrations in different organs. The deficient diet contained nutritionally essential linoleic acid (LA,18:2n-6) as 2.3% of total fatty acids (10% of the recommended minimum LA requirement for rodents) but no arachidonic acid (AA, 20:4n-6), and an adequate amount (4.8% of total fatty acids) of alpha-linolenic acid (18:3n-3). The deficient compared with adequate diet did not significantly affect body weight, but decreased testis weight by 10%. AA concentration was decreased significantly in serum (-86%), brain (-27%), liver (-68%), heart (-39%), testis (-25%), and epididymal adipose tissue (-77%). Eicosapentaenoic (20:5n-3) and docosahexaenoic acid (22:6n-3) concentrations were increased in all but adipose tissue, and the total monounsaturated fatty acid concentration was increased in all organs. The concentration of 20:3n-9, a marker of LA deficiency, was increased by the deficient diet, and serum concentrations of triacylglycerol, total cholesterol and total phospholipid were reduced. In summary, 15 weeks of dietary n-6 PUFA deficiency with n-3 PUFA adequacy significantly reduced n-6 PUFA concentrations in different organs of male rats, while increasing n-3 PUFA and monounsaturated fatty acid concentrations. This rat model could be used to study metabolic, functional and behavioral effects of dietary n-6 PUFA deficiency.
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Affiliation(s)
- Miki Igarashi
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Room 1S126, Bethesda, MD 20892, USA.
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Murray RJ, Pearson JC, Coombs GW, Flexman JP, Golledge CL, Speers DJ, Dyer JR, McLellan DG, Reilly M, Bell JM, Bowen SF, Christiansen KJ. Outbreak of invasive methicillin-resistant Staphylococcus aureus infection associated with acupuncture and joint injection. Infect Control Hosp Epidemiol 2008; 29:859-65. [PMID: 18684094 DOI: 10.1086/590260] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To describe an outbreak of invasive methicillin-resistant Staphylococcus aureus (MRSA) infection after percutaneous needle procedures (acupuncture and joint injection) performed by a single medical practitioner. SETTING A medical practitioner's office and 4 hospitals in Perth, Western Australia. PATIENTS Eight individuals who developed invasive MRSA infection after acupuncture or joint injection performed by the medical practitioner. METHODS We performed a prospective and retrospective outbreak investigation, including MRSA colonization surveillance, environmental sampling for MRSA, and detailed molecular typing of MRSA isolates. We performed an infection control audit of the medical practitioner's premises and practices and administered MRSA decolonization therapy to the medical practitioner. RESULTS Eight cases of invasive MRSA infection were identified. Seven cases occurred as a cluster in May 2004; another case (identified retrospectively) occurred approximately 15 months earlier in February 2003. The primary sites of infection were the neck, shoulder, lower back, and hip: 5 patients had septic arthritis and bursitis, and 3 had pyomyositis; 3 patients had bacteremia, including 1 patient with possible endocarditis. The medical practitioner was found to be colonized with the same MRSA clone [ST22-MRSA-IV (EMRSA-15)] at 2 time points: shortly after the first case of infection in March 2003 and again in May 2004. After the medical practitioner's premises and practices were audited and he himself received MRSA decolonization therapy, no further cases were identified. CONCLUSIONS This outbreak most likely resulted from a breakdown in sterile technique during percutaneous needle procedures, resulting in the transmission of MRSA from the medical practitioner to the patients. This report demonstrates the importance of surveillance and molecular typing in the identification and control of outbreaks of MRSA infection.
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Affiliation(s)
- R J Murray
- Department of Microbiology and Infectious Diseases, PathWest Laboratory Medicine WA-Royal Perth Hospital, West Perth, Perth, Western Australia.
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Bhattacharjee AK, Chang L, Chen M, White L, Bell JM, Bazinet RP, Rapoport SI. Chronic d-amphetamine depresses an imaging marker of arachidonic acid metabolism in rat brain. Int J Neuropsychopharmacol 2008; 11:957-69. [PMID: 18570702 PMCID: PMC2676692 DOI: 10.1017/s1461145708008833] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acute d-amphetamine (d-Amph) administration to rats leads to the release of arachidonic acid (AA, 20:4n-6) as a second messenger following indirect agonism at dopamine D2-like receptors in the brain. We hypothesized that chronically administered d-Amph in rats also would alter brain AA metabolism and signalling. To test this, adult male rats were injected i.p. daily for 2 wk with saline or 2.5 mg/kg d-Amph. After a 1-d washout, the unanaesthetized rats were injected acutely with i.v. saline, 1 mg/kg quinpirole (a D2-like receptor agonist) or 5.0 mg/kg SKF-38393 (a D1-like receptor agonist), followed by i.v. [1-14C]AA. The AA incorporation coefficient k* (brain radioactivity/integrated plasma radioactivity), a marker of AA signalling and metabolism, was quantified using autoradiography in each of 62 brain regions. Compared with chronic saline, chronic d-Amph widely decreased baseline values of k* in brain regions having D2-like receptors. On the other hand, chronic amphetamine did not alter the k* responses to quinpirole seen in chronic saline-treated rats. SKF-38393 had minimal effects on k* in both chronic saline-treated and amphetamine-treated rats, consistent with D1-like receptors not being coupled to AA signalling. The ability of chronic d-Amph after 1-d washout to down-regulate baseline values of k* probably reflects neuroplastic changes in brain AA signalling, and may correspond to depressive behaviours noted following withdrawal from chronic amphetamine in humans and in rats.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Arachidonic Acid/metabolism
- Arachidonic Acid/pharmacokinetics
- Autoradiography
- Biomarkers/analysis
- Biomarkers/metabolism
- Brain Chemistry/drug effects
- Central Nervous System Stimulants/administration & dosage
- Central Nervous System Stimulants/pharmacology
- Depression, Chemical
- Dextroamphetamine/administration & dosage
- Dextroamphetamine/pharmacology
- Dopamine Agonists/pharmacology
- Fatty Acids, Nonesterified/blood
- Half-Life
- Image Processing, Computer-Assisted
- Injections, Intraperitoneal
- Male
- Quinpirole/pharmacology
- Rats
- Rats, Inbred F344
- Receptors, Dopamine D2/agonists
- Receptors, Phospholipase A2/drug effects
- Signal Transduction/drug effects
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Affiliation(s)
- Abesh K Bhattacharjee
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
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Basselin M, Chang L, Chen M, Bell JM, Rapoport SI. Chronic administration of valproic acid reduces brain NMDA signaling via arachidonic acid in unanesthetized rats. Neurochem Res 2008; 33:2229-40. [PMID: 18461450 PMCID: PMC2564799 DOI: 10.1007/s11064-008-9700-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 04/03/2008] [Indexed: 01/12/2023]
Abstract
Evidence that brain glutamatergic activity is pathologically elevated in bipolar disorder suggests that mood stabilizers are therapeutic in the disease in part by downregulating glutamatergic activity. Such activity can involve the second messenger, arachidonic acid (AA, 20:4n - 6). We tested this hypothesis with regard to valproic acid (VPA), when stimulating glutamatergic N-methyl-D: -aspartate (NMDA) receptors in rat brain and measuring AA and related responses. An acute subconvulsant dose of NMDA (25 mg/kg i.p.) or saline was administered to unanesthetized rats that had been treated i.p. daily with VPA (200 mg/kg) or vehicle for 30 days. Quantitative autoradiography following intravenous [1-(14)C]AA infusion was used to image regional brain AA incorporation coefficients k*, markers of AA signaling. In chronic vehicle-pretreated rats, NMDA compared with saline significantly increased k* in 41 of 82 examined brain regions, many of which have high NMDA receptor densities, and also increased brain concentrations of the AA metabolites, prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)). VPA pretreatment reduced baseline concentrations of PGE(2) and TXB(2), and blocked the NMDA induced increases in k* and in eicosanoid concentrations. These results, taken with evidence that carbamazepine and lithium also block k* responses to NMDA in rat brain, suggest that mood stabilizers act in bipolar disorder in part by downregulating glutamatergic signaling involving AA.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg 9, Room 1S126, MSC 0947, 9 Memorial Drive, Bethesda, MD, 20892, USA.
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12
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Igarashi M, Ma K, Chang L, Bell JM, Rapoport SI. Rat heart cannot synthesize docosahexaenoic acid from circulating alpha-linolenic acid because it lacks elongase-2. J Lipid Res 2008; 49:1735-45. [PMID: 18456640 PMCID: PMC6075821 DOI: 10.1194/jlr.m800093-jlr200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The extent to which the heart can convert alpha-linolenic acid (alpha-LNA, 18:3n-3) to longer chain n-3 PUFAs is not known. Conversion rates can be measured in vivo using radiolabeled alpha-LNA and a kinetic fatty acid model. [1-(14)C]alpha-LNA was infused intravenously for 5 min in unanesthetized rats that had been fed an n-3 PUFA-adequate [4.6% alpha-LNA, no docosahexaenoic acid (DHA, 22:6n-3)] or n-3 PUFA-deficient diet (0.2% alpha-LNA, nor DHA) for 15 weeks after weaning. Arterial plasma was sampled, as was the heart after high-energy microwaving. Rates of conversion of alpha-LNA to longer chain n-3 PUFAs were low, and DHA was not synthesized at all in the heart. Most alpha-LNA within the heart had been beta-oxidized. In deprived compared with adequate rats, DHA concentrations in plasma and heart were both reduced by >90%, whereas heart and plasma levels of docosapentaenoic acid (DPAn-6, 22:5n-6) were elevated. Dietary deprivation did not affect cardiac mRNA levels of elongase-5 or desaturases Delta6 and Delta5, but elongase-2 mRNA could not be detected. In summary, the rat heart does not synthesize DHA from alpha-LNA, owing to the absence of elongase-2, but must obtain its DHA entirely from plasma. Dietary n-3 PUFA deprivation markedly reduces heart DHA and increases heart DPAn-6, which may make the heart vulnerable to different insults.
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Affiliation(s)
- Miki Igarashi
- Brain Physiology and Metabolism Section, National Institute on Aging, NIH, Bethesda, MD 20892, USA.
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13
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Basselin M, Chang L, Chen M, Bell JM, Rapoport SI. Chronic carbamazepine administration attenuates dopamine D2-like receptor-initiated signaling via arachidonic acid in rat brain. Neurochem Res 2008; 33:1373-83. [PMID: 18302021 PMCID: PMC5240792 DOI: 10.1007/s11064-008-9595-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 01/10/2008] [Indexed: 12/25/2022]
Abstract
Observations that dopaminergic antagonists are beneficial in bipolar disorder and that dopaminergic agonists can produce mania suggest that bipolar disorder involves excessive dopaminergic transmission. Thus, mood stabilizers used to treat the disease might act in part by downregulating dopaminergic transmission. In agreement, we reported that dopamine D2-like receptor mediated signaling involving arachidonic acid (AA, 20:4n-6) was downregulated in rats chronically treated with lithium. To see whether chronic carbamazepine, another mood stabilizer, did this as well, we injected i.p. saline or the D2-like receptor agonist, quinpirole (1 mg/kg), into unanesthetized rats that had been pretreated for 30 days with i.p. carbamazepine (25 mg/kg/day) or vehicle, and used quantitative autoradiography to measure regional brain incorporation coefficients (k*) for AA, markers of signaling. We also measured brain prostaglandin E2 (PGE2), an AA metabolite. In vehicle-treated rats, quinpirole compared with saline significantly increased k* for AA in 35 of 82 brain regions examined, as well as brain PGE2 concentration. Affected regions belong to dopaminergic circuits and have high D2-like receptor densities. Chronic carbamazepine pretreatment prevented the quinpirole-induced increments in k* and in PGE2. These findings are consistent with the hypothesis that effective mood stabilizers generally downregulate brain AA signaling via D2-like receptors, and that this signaling is upregulated in bipolar disorder.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Room 1S126, Bethesda, MD 20892, USA.
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Rybachuk M, Bell JM. Growth of diamond-like carbon films using low energy ion beam sputter - bombardment deposition with Ar ions. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/100/8/082009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Dixit MP, Nguyen C, Carson T, Guedes B, Dixit NM, Bell JM, Wang Y. Non-steroidal anti-inflammatory drugs-associated acute interstitial nephritis with granular tubular basement membrane deposits. Pediatr Nephrol 2008; 23:145-8. [PMID: 17879100 DOI: 10.1007/s00467-007-0585-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Revised: 07/12/2007] [Accepted: 07/16/2007] [Indexed: 01/28/2023]
Abstract
Acute tubulo-interstitial nephritis (ATIN) is an important cause of acute renal failure resulting from a variety of insults, including immune complex-mediated tubulo-interstitial injury, but drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) are a far more frequent cause. Overall, as an entity, ATIN remains under-diagnosed, as symptoms resolve spontaneously if the medication is stopped. We report on a 14-year-old boy who developed acute renal failure 2 weeks after aortic valve surgery. He was put on aspirin following surgery and took ibuprofen for fever for nearly a week prior to presentation. He then presented to the emergency department feeling quite ill and was found to have a blood urea nitrogen (BUN) concentration of of 147 mg/dl, creatinine of 15.3 mg/dl and serum potassium of 8.7 mEq/l. Dialysis was immediately initiated. A kidney biopsy showed inflammatory infiltrate consistent with ATIN. However, in the tubular basement membrane (TBM), very intense granular deposits of polyclonal IgG and C3 were noted. He needed dialysis for 2 weeks and was treated successfully with steroids for 6 months. His renal recovery and disappearance of proteinuria took a year. In conclusion, this is a first report of NSAIDs-associated ATIN, showing deposits of granular immune complex present only in the TBM and not in the glomeruli.
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Affiliation(s)
- Mehul P Dixit
- Florida Children's Kidney Center, Department of Pediatrics, Florida Children's Hospital, 615 E. Princeton, Suite 500, Orlando, FL 32803, USA.
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16
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Sublette ME, Bosetti F, DeMar JC, Ma K, Bell JM, Fagin-Jones S, Russ MJ, Rapoport SI. Plasma free polyunsaturated fatty acid levels are associated with symptom severity in acute mania. Bipolar Disord 2007; 9:759-65. [PMID: 17988367 PMCID: PMC2238693 DOI: 10.1111/j.1399-5618.2007.00387.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Nutritionally essential polyunsaturated fatty acids (PUFAs) have been implicated as potentially important factors in mood disorders. For instance, n-3 PUFA supplementation is reported to improve outcomes in major depressive disorder and bipolar disorder. However, the role of PUFAs in acute mania has been minimally investigated. We performed a pilot study to compare plasma levels of free (non-esterified) and esterified PUFAs between patients in an acute manic episode and healthy volunteers, and to explore associations between symptom severity and levels of fatty acids and of the arachidonic acid metabolite, prostaglandin E2 (PGE2). METHODS Patients (n=10) who were medication-free for at least two weeks and seeking inpatient admission for an acute manic episode were compared with healthy volunteers (n=10). Symptom severity was assessed at admission and after six weeks of naturalistic treatment. Fasting baseline free and esterified plasma levels of docosahexaneoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3), arachidonic acid (AA,20:4n-6) and the AA metabolite PGE2 were determined, and PGE2 levels were tested again at six weeks. RESULTS No between-group differences were found in levels of individual or total fatty acids, or of PGE2. Among subjects, manic symptom severity correlated negatively with levels of free AA and free EPA, and positively with the free AA:EPA ratio. PGE2 levels did not differ between groups or in subjects pre- and post-treatment. CONCLUSIONS Our preliminary results suggest that, in susceptible persons, low plasma levels of free EPA compared with AA are related to the severity of mania.
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Affiliation(s)
- M Elizabeth Sublette
- Department of Neuroscience, New York State Psychiatric Institute, Columbia University, New York, NY 10032, USA.
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Basselin M, Villacreses NE, Chen M, Bell JM, Rapoport SI. Chronic carbamazepine administration reduces N-methyl-D-aspartate receptor-initiated signaling via arachidonic acid in rat brain. Biol Psychiatry 2007; 62:934-43. [PMID: 17628508 PMCID: PMC2131715 DOI: 10.1016/j.biopsych.2007.04.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 04/11/2007] [Accepted: 04/11/2007] [Indexed: 01/16/2023]
Abstract
BACKGROUND Lithium and carbamazepine (CBZ) are used to treat mania in bipolar disorder. When given chronically to rats, both agents reduce arachidonic acid (AA) turnover in brain phospholipids and downstream AA metabolism. Lithium in rats also attenuates brain N-methyl-D-aspartic acid receptor (NMDAR) signaling via AA. We hypothesized that, like chronic lithium, chronic CBZ administration to rats would reduce NMDAR-mediated signaling via AA. METHODS We used our fatty acid method with quantitative autoradiography to image the regional brain incorporation coefficient k* of AA, a marker of AA signaling, in unanesthetized rats that had been given 25 mg/kg/day I.P. CBZ or vehicle for 30 days, then injected with NMDA (25 mg/kg I.P.) or saline. We also measured brain concentrations of two AA metabolites, prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)). RESULTS In chronic vehicle-treated rats, NMDA compared with saline increased k* significantly in 69 of 82 brain regions examined, but did not change k* significantly in any region in CBZ-treated rats. In vehicle- but not CBZ-treated rats, NMDA also increased brain concentrations of PGE(2) and TXB(2). CONCLUSIONS Chronic CBZ administration to rats blocks increments in the AA signal k*, and in PGE(2) and TXB(2) concentrations that are produced by NMDA in vehicle-treated rats. The clinical action of antimanic drugs might involve inhibition of brain NMDAR-mediated signaling involving AA and its metabolites.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Igarashi M, Ma K, Chang L, Bell JM, Rapoport SI. Dietary n-3 PUFA deprivation for 15 weeks upregulates elongase and desaturase expression in rat liver but not brain. J Lipid Res 2007; 48:2463-70. [PMID: 17715424 DOI: 10.1194/jlr.m700315-jlr200] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Fifteen weeks of dietary n-3 PUFA deprivation increases coefficients of conversion of circulating alpha-linolenic acid (alpha-LNA; 18:3n-3) to docosahexaenoic acid (DHA; 22:6n-3) in rat liver but not brain. To determine whether these increases reflect organ differences in enzymatic activities, we examined brain and liver expression of converting enzymes and of two of their transcription factors, peroxisome proliferator-activated receptor alpha (PPARalpha) and sterol-regulatory element binding protein-1 (SREBP-1), in rats fed an n-3 PUFA "adequate" (4.6% alpha-LNA of total fatty acid, no DHA) or "deficient" (0.2% alpha-LNA, no DHA) diet for 15 weeks after weaning. In rats fed the deficient compared with the adequate diet, mRNA and activity levels of Delta5 and Delta6 desaturases and elongases 2 and 5 were upregulated in liver but not brain, but liver PPARalpha and SREBP-1 mRNA levels were unchanged. In rats fed the adequate diet, enzyme activities generally were higher in liver than brain. Thus, differences in conversion enzyme expression explain why the liver has a greater capacity to synthesize DHA from circulating alpha-LNA than does the brain in animals on an adequate n-3 PUFA diet and why liver synthesis capacity is increased by dietary deprivation. These data suggest that liver n-3 PUFA metabolism determines DHA availability to the brain when DHA is absent from the diet.
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Affiliation(s)
- Miki Igarashi
- Brain Physiology and Metabolism Section, National Institute on Aging, NIH, Bethesda, MD 20892, USA.
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Basselin M, Villacreses NE, Lee HJ, Bell JM, Rapoport SI. Flurbiprofen, A Cyclooxygenase Inhibitor, Reduces the Brain Arachidonic Acid Signal in Response to the Cholinergic Muscarinic Agonist, Arecoline, in Awake Rats. Neurochem Res 2007; 32:1857-67. [PMID: 17562170 DOI: 10.1007/s11064-007-9372-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
Cholinergic muscarinic receptors, when stimulated by arecoline, can activate cytosolic phospholipase A(2) (cPLA(2)) to release arachidonic acid (AA) from membrane phospholipid. This signal can be imaged in the brain in vivo using quantitative autoradiography following the intravenous injection of radiolabeled AA, as an increment in a regional brain AA incorporation coefficient k*. Arecoline increases k* significantly in brain regions having muscarinic M(1,3,5) receptors in wild-type but not in cyclooxygenase (COX)-2 knockout mice. To further clarify the roles of COX enzymes in the AA signal, in this paper we imaged k* following arecoline (5 mg/kg i.p.) or saline in each of 81 brain regions of unanesthetized rats pretreated 6 h earlier with the non-selective COX inhibitor flurbiprofen (FB, 60 mg/kg s.c.) or with vehicle. Baseline values of k* were unaffected by FB treatment, which however reduced by 80% baseline brain concentrations of prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)), eicosanoids preferentially derived from AA via COX-2 and COX-1, respectively. In vehicle-pretreated rats, arecoline increased the brain PGE(2) but not TXB(2) concentration, as well as values for k* in 77 of the 81 brain regions. FB-pretreatment prevented these arecoline-provoked changes. These results and those reported in COX-2 knockout mice suggest that the AA released in brain following muscarinic receptor-mediated activation is lost via COX-2 to PGE(2) but not via COX-1 to TXB(2), and that increments in k* following arecoline largely represent replacement by unesterified plasma AA of this loss.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg 9, Room 1S126, MSC 0947, 9 Memorial Drive, Bethesda, MD 20892, USA.
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Igarashi M, DeMar JC, Ma K, Chang L, Bell JM, Rapoport SI. Docosahexaenoic acid synthesis from α-linolenic acid by rat brain is unaffected by dietary n-3 PUFA deprivation. J Lipid Res 2007; 48:1150-8. [PMID: 17277380 DOI: 10.1194/jlr.m600549-jlr200] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rates of conversion of alpha-linolenic acid (alpha-LNA, 18:3n-3) to docosahexaenoic acid (DHA, 22:6n-3) by the mammalian brain and the brain's ability to upregulate these rates during dietary deprivation of n-3 polyunsaturated fatty acids (PUFAs) are unknown. To answer these questions, we measured conversion coefficients and rates in post-weaning rats fed an n-3 PUFA deficient (0.2% alpha-LNA of total fatty acids, no DHA) or adequate (4.6% alpha-LNA, no DHA) diet for 15 weeks. Unanesthetized rats in each group were infused intravenously with [1-(14)C]alpha-LNA, and their arterial plasma and microwaved brains collected at 5 minutes were analyzed. The deficient compared with adequate diet reduced brain DHA by 37% and increased brain arachidonic (20:4n-6) and docosapentaenoic (22:5n-6) acids. Only 1% of plasma [1-(14)C]alpha-LNA entering brain was converted to DHA with the adequate diet, and conversion coefficients of alpha-LNA to DHA were unchanged by the deficient diet. In summary, the brain's ability to synthesize DHA from alpha-LNA is very low and is not altered by n-3 PUFA deprivation. Because the liver's reported ability is much higher, and can be upregulated by the deficient diet, DHA converted by the liver from circulating alphaLNA is the source of the brain's DHA when DHA is not in the diet.
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Affiliation(s)
- Miki Igarashi
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Igarashi M, DeMar JC, Ma K, Chang L, Bell JM, Rapoport SI. The conversion rate to docosahexaenoic acid from alpha‐linolenic acid in rat liver: Effects of n‐3 PUFA deprivation. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - James C DeMar
- BPMS, NIA, NIH9000 Rockville PikeBethesdaMD20892
- NIAAA, NIH5625 Fishers LaneBethesdaMD20892
| | - Kaizong Ma
- BPMS, NIA, NIH9000 Rockville PikeBethesdaMD20892
| | - Lisa Chang
- BPMS, NIA, NIH9000 Rockville PikeBethesdaMD20892
| | - Jane M Bell
- BPMS, NIA, NIH9000 Rockville PikeBethesdaMD20892
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Basselin M, Villacreses NE, Lee HJ, Bell JM, Rapoport SI. Chronic lithium administration attenuates up-regulated brain arachidonic acid metabolism in a rat model of neuroinflammation. J Neurochem 2007; 102:761-72. [PMID: 17488274 DOI: 10.1111/j.1471-4159.2007.04593.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neuroinflammation, caused by a 6-day intracerebroventricular infusion of lipopolysaccharide (LPS) in rats, is associated with the up-regulation of brain arachidonic acid (AA) metabolism markers. Because chronic LiCl down-regulates markers of brain AA metabolism, we hypothesized that it would attenuate increments of these markers in LPS-infused rats. Incorporation coefficients k* of AA from plasma into brain, and other brain AA metabolic markers, were measured in rats that had been fed a LiCl or control diet for 6 weeks, and subjected in the last 6 days on the diet to intracerebroventricular infusion of artificial CSF or of LPS. In rats on the control diet, LPS compared with CSF infusion increased k* significantly in 28 regions, whereas the LiCl diet prevented k* increments in 18 of these regions. LiCl in CSF infused rats increased k* in 14 regions, largely belonging to auditory and visual systems. Brain cytoplasmic phospholipase A(2) activity, and prostaglandin E(2) and thromboxane B(2) concentrations, were increased significantly by LPS infusion in rats fed the control but not the LiCl diet. Chronic LiCl administration attenuates LPS-induced up-regulation of a number of brain AA metabolism markers. To the extent that this up-regulation has neuropathological consequences, lithium might be considered for treating human brain diseases accompanied by neuroinflammation.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda 20892-0947, Maryland, USA.
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Igarashi M, DeMar JC, Ma K, Chang L, Bell JM, Rapoport SI. Upregulated liver conversion of alpha-linolenic acid to docosahexaenoic acid in rats on a 15 week n-3 PUFA-deficient diet. J Lipid Res 2006; 48:152-64. [PMID: 17050905 DOI: 10.1194/jlr.m600396-jlr200] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We quantified incorporation rates of plasma-derived alpha-linolenic acid (alpha-LNA, 18:3n-3) into "stable" liver lipids and the conversion rate of alpha-LNA to docosahexaenoic acid (DHA, 22:6n-3) in male rats fed, after weaning, an n-3 PUFA-adequate diet (4.6% alpha-LNA, no DHA) or an n-3 PUFA-deficient diet (0.2% alpha-LNA, no DHA) for 15 weeks. Unanesthetized rats were infused intravenously with [1-14C]alpha-LNA, and arterial plasma was sampled until the liver was microwaved at 5 min. Unlabeled alpha-LNA and DHA concentrations in arterial plasma and liver were reduced >90% by deprivation, whereas unlabeled arachidonic acid (20:4n-6) and docosapentaenoic acid (22:5n-6) concentrations were increased. Deprivation did not change alpha-LNA incorporation coefficients into stable liver lipids but increased synthesis-incorporation coefficients of DHA from alpha-LNA by 6.6-, 8.4-, and 2.3-fold in triacylglycerol, phospholipid, and cholesteryl ester, respectively. Assuming that synthesized-incorporated DHA eventually would be secreted within lipoproteins, calculated liver DHA secretion rates equaled 2.19 and 0.82 micromol/day in the n-3 PUFA-adequate and -deprived rats, respectively. These rates exceed the published rates of brain DHA consumption by 6- and 10-fold, respectively, and should be sufficient to maintain normal and reduced brain DHA concentrations, respectively, in the two dietary conditions.
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Affiliation(s)
- Miki Igarashi
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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DeMar JC, Lee HJ, Ma K, Chang L, Bell JM, Rapoport SI, Bazinet RP. Brain elongation of linoleic acid is a negligible source of the arachidonate in brain phospholipids of adult rats. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1050-9. [PMID: 16920015 DOI: 10.1016/j.bbalip.2006.06.006] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 06/19/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
The extent to which the adult brain can derive some of its arachidonic acid (AA) through internalized synthesis from linoleic acid (LA) is uncertain. Thus, we determined for plasma-derived LA in vivo rates for brain incorporation, beta-oxidation, and conversion to AA. Adult male unanesthetized rats, reared on a diet enriched in LA but low in AA, were infused intravenously for 5 min with [1-(14)C]LA. Timed arterial samples were collected until the animals were killed at 5 min and the brain was removed after microwaving. Within plasma lipids, >96% of radioactivity was in the form of unchanged [1-(14)C]LA, but [(14)C]AA was insignificant (<0.2%). Eighty-six percent of brain radioactivity at 5 min was present as beta-oxidation products, whereas the remainder was mainly in 'stable' phospholipid or triglyceride as LA or AA (11 and <1%, respectively). Unesterified unlabeled LA rapidly enters brain from plasma, but its incorporation into brain total phospholipid and triglyceride, in the form of synthesized AA, is <1% of the amount that enters the brain. Thus, in rats fed even a diet containing low amounts of AA, the LA that enters brain is largely beta-oxidized, and is not a major source of AA in brain.
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Affiliation(s)
- James C DeMar
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Building 9, Room 1S 126, Bethesda, MD 20892-1582, USA
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Abstract
Acute Q fever is a zoonotic infection that most often occurs as an asymptomatic or very mild febrile illness. A small percentage of patients go on to develop chronic Q fever months or even years after the acute infection. We present a case of acute Q fever occurring in a renal transplant recipient who developed severe systemic disease with renal involvement. Serological diagnosis was carried out, and the patient was treated successfully with antibiotic therapy. This case emphasizes Q fever as one of the atypical infectious agents that may have serious consequences in immunocompromised renal transplant recipients and reminds us of the importance of careful inquiry regarding personal or occupational activities that could lead to exposure to specific organisms.
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Affiliation(s)
- Christopher P Larsen
- University of Arkansas for Medical Sciences, NephroPath, Little Rock, AR 72211, USA
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Basselin M, Chang L, Bell JM, Rapoport SI. Chronic lithium chloride administration attenuates brain NMDA receptor-initiated signaling via arachidonic acid in unanesthetized rats. Neuropsychopharmacology 2006; 31:1659-74. [PMID: 16292331 DOI: 10.1038/sj.npp.1300920] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It has been proposed that lithium is effective in bipolar disorder (BD) by inhibiting glutamatergic neurotransmission, particularly via N-methyl-D-aspartate receptors (NMDARs). To test this hypothesis and to see if the neurotransmission could involve the NMDAR-mediated activation of phospholipase A2 (PLA2), to release arachidonic acid (AA) from membrane phospholipid, we administered subconvulsant doses of NMDA to unanesthetized rats fed a chronic control or LiCl diet. We used quantitative autoradiography following the intravenous injection of radiolabeled AA to measure regional brain incorporation coefficients k* for AA, which reflect receptor-mediated activation of PLA2. In control diet rats, NMDA (25 and 50 mg/kg i.p.) compared with i.p. saline increased k* significantly in 49 and 67 regions, respectively, of the 83 brain regions examined. The regions affected were those with reported NMDARs, including the neocortex, hippocampus, caudate-putamen, thalamus, substantia nigra, and nucleus accumbens. The increases could be blocked by pretreatment with the specific noncompetitive NMDA antagonist MK-801 ((5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate) (0.3 mg/kg i.p.), as well by a 6-week LiCl diet sufficient to produce plasma and brain lithium concentrations known to be effective in BD. MK-801 alone reduced baseline values for k* in many brain regions. The results show that it is possible to image NMDA signaling via PLA2 activation and AA release in vivo, and that chronic lithium blocks this signaling, consistent with its suggested mechanism of action in BD.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Igarashi M, Ma K, Chang L, Bell JM, Rapoport SI, DeMar JC. Low liver conversion rate of alpha-linolenic to docosahexaenoic acid in awake rats on a high-docosahexaenoate-containing diet. J Lipid Res 2006; 47:1812-22. [PMID: 16687661 DOI: 10.1194/jlr.m600030-jlr200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We quantified the rates of incorporation of alpha-linolenic acid (alpha-LNA; 18:3n-3) into "stable" lipids (triacylglycerol, phospholipid, cholesteryl ester) and the rate of conversion of alpha-LNA to docosahexaenoic acid (DHA; 22: 6n-3) in the liver of awake male rats on a high-DHA-containing diet after a 5-min intravenous infusion of [1-(14)C]alpha-LNA. At 5 min, 72.7% of liver radioactivity (excluding unesterified fatty acid radioactivity) was in stable lipids, with the remainder in the aqueous compartment. Using our measured specific activity of liver alpha-LNA-CoA, in the form of the dilution coefficient lambda(alpha-LNA-CoA), we calculated incorporation rates of unesterified alpha-LNA into liver triacylglycerol, phospholipid, and cholesteryl ester as 2,401, 749, and 9.6 nmol/s/g x 10(-4), respectively, corresponding to turnover rates of 3.2, 8.7, and 2.9%/min and half-lives of 8-24 min. A lower limit for the DHA synthesis rate from alpha-LNA equaled 15.8 nmol/s/g x 10(-4) (0.5% of the net in corporation rate). Thus, in rats on a high-DHA-containing diet, rates of beta-oxidation and esterification of alpha-LNA into stable liver lipids are high, whereas its conversion to DHA is comparatively low and insufficient to supply significant DHA to the brain. High incorporation and turnover rates likely reflect a high secretion rate by liver of stable lipids within very low density lipoproteins.
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Affiliation(s)
- Miki Igarashi
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Basselin M, Villacreses NE, Langenbach R, Ma K, Bell JM, Rapoport SI. Resting and arecoline-stimulated brain metabolism and signaling involving arachidonic acid are altered in the cyclooxygenase-2 knockout mouse. J Neurochem 2006; 96:669-79. [PMID: 16405503 DOI: 10.1111/j.1471-4159.2005.03612.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Abstract Studies were performed to determine if cyclooxygenase (COX)-2 regulates muscarinic receptor-initiated signaling involving brain phospholipase A2 (PLA2) activation and arachidonic acid (AA; 20 : 4n-6) release. AA incorporation coefficients, k* (brain [1-14C]AA radioactivity/integrated plasma radioactivity), representing this signaling, were measured following the intravenous injection of [1-14C]AA using quantitative autoradiography, in each of 81 brain regions in unanesthetized COX-2 knockout (COX-2(-/-)) and wild-type (COX-2(+/+)) mice. Mice were administered arecoline (30 mg/kg i.p.), a non-specific muscarinic receptor agonist, or saline i.p. (baseline control). At baseline, COX-2(-/-) compared with COX-2(+/+) mice had widespread and significant elevations of k*. Arecoline increased k* significantly in COX-2(+/+) mice compared with saline controls in 72 of 81 brain regions, but had no significant effect on k* in any region in COX-2(-/-) mice. These findings, when related to net incorporation rates of AA from brain into plasma, demonstrate enhanced baseline brain metabolic loss of AA in COX-2(-/-) compared with COX-2(+/+) mice, and an absence of a normal k* response to muscarinic receptor activation. This response likely reflects selective COX-2-mediated conversion of PLA2-released AA to prostanoids.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda,MD 20892-0947, USA.
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DeMar JC, Ma K, Bell JM, Igarashi M, Greenstein D, Rapoport SI. One generation of n-3 polyunsaturated fatty acid deprivation increases depression and aggression test scores in rats. J Lipid Res 2006; 47:172-80. [PMID: 16210728 DOI: 10.1194/jlr.m500362-jlr200] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Male rat pups at weaning (21 days of age) were subjected to a diet deficient or adequate in n-3 polyunsaturated fatty acids (n-3 PUFAs) for 15 weeks. Performance on tests of locomotor activity, depression, and aggression was measured in that order during the ensuing 3 weeks, after which brain lipid composition was determined. In the n-3 PUFA-deprived rats, compared with n-3 PUFA-adequate rats, docosahexaenoic acid (22:6n-3) in brain phospholipid was reduced by 36% and docosapentaenoic acid (22:5n-6) was elevated by 90%, whereas brain phospholipid concentrations were unchanged. N-3 PUFA-deprived rats had a significantly increased (P = 0.03) score on the Porsolt forced-swim test for depression, and increased blocking time (P = 0.03) and blocking number (P = 0.04) scores (uncorrected for multiple comparisons) on the isolation-induced resident-intruder test for aggression. Large effect sizes (d > 0.8) were found on the depression score and on the blocking time score of the aggression test. Scores on the open-field test for locomotor activity did not differ significantly between groups, and had only small to medium effect sizes. This single-generational n-3 PUFA-deprived rat model, which demonstrated significant changes in brain lipid composition and in test scores for depression and aggression, may be useful for elucidating the contribution of disturbed brain PUFA metabolism to human depression, aggression, and bipolar disorder.
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Affiliation(s)
- James C DeMar
- Brain Physiology and Metabolism Section, National Institute on Aging, and Child Psychiatry Branch, National Institutes of Health Bethesda, MD, 20892, USA
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Demar JC, Ma K, Chang L, Bell JM, Rapoport SI. α-Linolenic acid does not contribute appreciably to docosahexaenoic acid within brain phospholipids of adult rats fed a diet enriched in docosahexaenoic acid. J Neurochem 2005; 94:1063-76. [PMID: 16092947 DOI: 10.1111/j.1471-4159.2005.03258.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adult male unanesthetized rats, reared on a diet enriched in both alpha-linolenic acid (alpha-LNA) and docosahexaenoic acid (DHA), were infused intravenously for 5 min with [1-(14)C]alpha-LNA. Timed arterial samples were collected until the animals were killed at 5 min and the brain was removed after microwaving. Plasma and brain lipid concentrations and radioactivities were measured. Within plasma lipids, > 99% of radioactivity was in the form of unchanged [1-(14)C]alpha-LNA. Eighty-six per cent of brain radioactivity at 5 min was present as beta-oxidation products, whereas the remainder was mainly in 'stable' phospholipid or triglyceride as alpha-LNA or DHA. Equations derived from kinetic modeling demonstrated that unesterified unlabeled alpha-LNA rapidly enters brain from plasma, but that its incorporation into brain phospholipid and triglyceride, as in the form of synthesized DHA, is < or = 0.2% of the amount that enters the brain. Thus, in rats fed a diet containing large amounts of both alpha-LNA and DHA, the alpha-LNA that enters brain from plasma largely undergoes beta-oxidation, and is not an appreciable source of DHA within brain phospholipids.
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Affiliation(s)
- James C Demar
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA
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Bosetti F, Bell JM, Manickam P. Microarray analysis of rat brain gene expression after chronic administration of sodium valproate. Brain Res Bull 2005; 65:331-8. [PMID: 15811599 DOI: 10.1016/j.brainresbull.2005.01.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Revised: 01/05/2005] [Accepted: 01/07/2005] [Indexed: 11/25/2022]
Abstract
Valproic acid has been used to treat mania and bipolar disorder, but its mechanism of action is not agreed on. We used rat genome U34A Affymetrix oligonucleotide microarrays, containing 8799 known probesets, to determine the effect of 30-day daily intraperitoneal administration of valproate (200mg/kg) on rat brain gene expression. We found 87 down-regulated genes and 34 up-regulated genes of at least a 1.4-fold change in valproate-treated compared to control rats. The experiments were done on five independent samples for each group, each in duplicate. The genes affected are known to be involved in a variety of pathways, including synaptic transmission, ion channels and transport, G-protein signaling, lipid, glucose and amino-acid metabolism, transcriptional and translational regulation, phosphoinositol cycle, protein kinases and phosphatases, and apoptosis. Our results suggest that the therapeutic effect of valproate may involve the modulation of multiple signaling pathways.
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Affiliation(s)
- Francesca Bosetti
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, 9000 Rockville Pike, Bldg. 10, Rm. 6N202, Bethesda, MD 20892, USA.
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Basselin M, Chang L, Bell JM, Rapoport SI. Chronic lithium chloride administration to unanesthetized rats attenuates brain dopamine D2-like receptor-initiated signaling via arachidonic acid. Neuropsychopharmacology 2005; 30:1064-75. [PMID: 15812572 DOI: 10.1038/sj.npp.1300671] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We studied the effect of lithium chloride on dopaminergic neurotransmission via D2-like receptors coupled to phospholipase A2 (PLA2). In unanesthetized rats injected i.v. with radiolabeled arachidonic acid (AA, 20:4 n-6), regional PLA2 activation was imaged by measuring regional incorporation coefficients k* of AA (brain radioactivity divided by integrated plasma radioactivity) using quantitative autoradiography, following administration of the D2-like receptor agonist, quinpirole. In rats fed a control diet, quinpirole at 1 mg/kg i.v. increased k* for AA significantly in 17 regions with high densities of D2-like receptors, of 61 regions examined. Increases in k* were found in the prefrontal cortex, frontal cortex, accumbens nucleus, caudate-putamen, substantia nigra, and ventral tegmental area. Quinpirole, 0.25 mg/kg i.v. enhanced k* significantly only in the caudate-putamen. In rats fed LiCl for 6 weeks to produce a therapeutically relevant brain lithium concentration, neither 0.25 mg/kg nor 1 mg/kg quinpirole increased k* significantly in any region. Orofacial movements following quinpirole were modified but not abolished by LiCl feeding. The results suggest that downregulation by lithium of D2-like receptor signaling involving PLA2 and AA may contribute to lithium's therapeutic efficacy in bipolar disorder.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Abstract
BACKGROUND Renal abnormalities discovered in the elderly have often been considered the result of aging, hypertensive changes, and so on. Recently, we noted an increase in renal biopsies among patients 80 years and older. This is a demographic subset with little or no previously reported clinicopathologic correlation between renal biopsy findings and clinical syndromes. METHODS We examined our files for all biopsies performed in patients 80 years and older and report 100 patients of a total of 3,227 biopsies (3.1%) from multiple referral centers. RESULTS Significant differences in the disease spectrum were found in the very elderly, not only compared with studies of adults and children, but also compared with studies of renal biopsies in the elderly. Crescentic glomerulonephritis was the most common diagnosis in patients aged 80 years and older. Although membranous glomerulopathy is the most common cause of idiopathic nephrotic syndrome in studies of the elderly (23% to 38%) and adults (35% to 40%), only 15% of our patients aged 80 years and older with idiopathic nephrotic syndrome had membranous nephropathy. Overall, at least 40 of 100 biopsies performed on the very elderly showed a renal condition that would benefit from therapeutic intervention, and the remaining biopsies provided at least prognostic information and/or ruled out a more severe condition, preventing potentially harmful empiric therapy. CONCLUSION As the population ages, more elderly patients are undergoing diagnostic renal biopsies. This study emphasizes the variance between clinical presentation and expected diagnosis compared with actual biopsy findings in patients aged 80 years and older.
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Affiliation(s)
- Ramesh Nair
- Nephropathology Associates, Little Rock, AR 72211, USA
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Basselin M, Chang L, Seemann R, Bell JM, Rapoport SI. Chronic lithium administration to rats selectively modifies 5-HT2A/2C receptor-mediated brain signaling via arachidonic acid. Neuropsychopharmacology 2005; 30:461-72. [PMID: 15562295 DOI: 10.1038/sj.npp.1300611] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The effects of chronic lithium administration on regional brain incorporation coefficients k* of arachidonic acid (AA), a marker of phospholipase A2 (PLA2) activation, were determined in unanesthetized rats administered i.p. saline or 1 mg/kg i.p. (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), a 5-HT2A/2C receptor agonist. After injecting [1-(14)C]AA intravenously, k* (brain radioactivity/integrated plasma radioactivity) was measured in each of 94 brain regions by quantitative autoradiography. Studies were performed in rats fed a LiCl or a control diet for 6 weeks. In the control diet rats, DOI significantly increased k* in widespread brain areas containing 5-HT2A/2C receptors. In the LiCl-fed rats, the significant positive k* response to DOI did not differ from that in control diet rats in most brain regions, except in auditory and visual areas, where the response was absent. LiCl did not change the head turning response to DOI seen in control rats. In summary, LiCl feeding blocked PLA2-mediated signal involving AA in response to DOI in visual and auditory regions, but not generally elsewhere. These selective effects may be related to lithium's therapeutic efficacy in patients with bipolar disorder, particularly its ability to ameliorate hallucinations in that disease.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Affiliation(s)
- Jane M Bell
- Nephropathology Associates, Little Rock, AR 72211, USA.
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DeMar JC, Ma K, Bell JM, Rapoport SI. Half-lives of docosahexaenoic acid in rat brain phospholipids are prolonged by 15 weeks of nutritional deprivation of n-3 polyunsaturated fatty acids. J Neurochem 2004; 91:1125-37. [PMID: 15569256 DOI: 10.1111/j.1471-4159.2004.02789.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Male rat pups (21 days old) were placed on a diet deficient in n-3 polyunsaturated fatty acids (PUFAs) or on an n-3 PUFA adequate diet containing alpha-linolenic acid (alpha-LNA; 18 : 3n-3). After 15 weeks on a diet, [4,5-3H]docosahexaenoic acid (DHA; 22 : 6n-3) was injected into the right lateral cerebral ventricle, and the rats were killed at fixed times over a period of 60 days. Compared with the adequate diet, 15 weeks of n-3 PUFA deprivation reduced plasma DHA by 89% and brain DHA by 37%; these DHA concentrations did not change thereafter. In the n-3 PUFA adequate rats, DHA loss half-lives, calculated by plotting log10 (DHA radioactivity) against time after tracer injection, equaled 33 days in total brain phospholipid, 23 days in phosphatidylcholine, 32 days in phosphatidylethanolamine, 24 days in phosphatidylinositol and 58 days in phosphatidylserine; all had a decay slope significantly greater than 0 (p < 0.05). In the n-3 PUFA deprived rats, these half-lives were prolonged twofold or greater, and calculated rates of DHA loss from brain, Jout, were reduced. Mechanisms must exist in the adult rat brain to minimize DHA metabolic loss, and to do so even more effectively in the face of reduced n-3 PUFA availability for only 15 weeks.
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Affiliation(s)
- James C DeMar
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892-1582, USA.
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Nair R, Bell JM, Walker PD. Renal biopsy in patients aged 80 years and older. Am J Kidney Dis 2004; 44:618-26. [PMID: 15384012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
BACKGROUND Renal abnormalities discovered in the elderly have often been considered the result of aging, hypertensive changes, and so on. Recently, we noted an increase in renal biopsies among patients 80 years and older. This is a demographic subset with little or no previously reported clinicopathologic correlation between renal biopsy findings and clinical syndromes. METHODS We examined our files for all biopsies performed in patients 80 years and older and report 100 patients of a total of 3,227 biopsies (3.1%) from multiple referral centers. RESULTS Significant differences in the disease spectrum were found in the very elderly, not only compared with studies of adults and children, but also compared with studies of renal biopsies in the elderly. Crescentic glomerulonephritis was the most common diagnosis in patients aged 80 years and older. Although membranous glomerulopathy is the most common cause of idiopathic nephrotic syndrome in studies of the elderly (23% to 38%) and adults (35% to 40%), only 15% of our patients aged 80 years and older with idiopathic nephrotic syndrome had membranous nephropathy. Overall, at least 40 of 100 biopsies performed on the very elderly showed a renal condition that would benefit from therapeutic intervention, and the remaining biopsies provided at least prognostic information and/or ruled out a more severe condition, preventing potentially harmful empiric therapy. CONCLUSION As the population ages, more elderly patients are undergoing diagnostic renal biopsies. This study emphasizes the variance between clinical presentation and expected diagnosis compared with actual biopsy findings in patients aged 80 years and older.
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Affiliation(s)
- Ramesh Nair
- Nephropathology Associates, Little Rock, AR 72211, USA
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Ghelardoni S, Tomita YA, Bell JM, Rapoport SI, Bosetti F. Chronic carbamazepine selectively downregulates cytosolic phospholipase A2 expression and cyclooxygenase activity in rat brain. Biol Psychiatry 2004; 56:248-54. [PMID: 15312812 DOI: 10.1016/j.biopsych.2004.05.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Revised: 04/19/2004] [Accepted: 05/24/2004] [Indexed: 11/28/2022]
Abstract
BACKGROUND Carbamazepine is a mood stabilizer used as monotherapy or as an adjunct to lithium in the treatment of acute mania or the prophylaxis of bipolar disorder. Based on evidence that lithium and valproate, other mood stabilizers, reduce brain arachidonic acid turnover and its conversion via cyclooxygenase to prostaglandin E(2) in rat brain, one possibility is that carbamazepine also targets the arachidonic acid cascade. METHODS To test this hypothesis, carbamazepine was administered to rats by intraperitoneal injection at a daily dose of 25 mg/kg for 30 days. RESULTS Carbamazepine decreased brain phospholipase A(2) activity and cytosolic phospholipase A(2) protein and messenger RNA levels without changing significantly protein and activity levels of calcium-independent phospholipase A(2) or secretory phospholipase A(2). Cyclooxygenase activity was decreased in carbamazepine-treated rats without any change in cyclooxygenase-1 or cyclooxygenase-2 protein levels. Brain prostaglandin E(2) concentration also was reduced. The protein levels of other arachidonic acid metabolizing enzymes, 5-lipoxygenase and cytochrome P450 epoxygenase, were not significantly changed nor was the brain concentration of the 5-lipoxygenase product leukotriene B(4). CONCLUSIONS Carbamazepine downregulates cytosolic phospholipase A(2)-mediated release of arachidonic acid and its subsequent conversion to prostaglandin E(2) by cyclooxygenase. These effects may contribute to its therapeutic actions in bipolar disorder.
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Affiliation(s)
- Sandra Ghelardoni
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA
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Christiansen KJ, Bell JM, Turnidge JD, Jones RN. Antimicrobial activities of garenoxacin (BMS 284756) against Asia-Pacific region clinical isolates from the SENTRY program, 1999 to 2001. Antimicrob Agents Chemother 2004; 48:2049-55. [PMID: 15155198 PMCID: PMC415570 DOI: 10.1128/aac.48.6.2049-2055.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Between 1999 and 2001, 16,731 isolates from the Asia-Pacific Region were tested in the SENTRY Program for susceptibility to six fluoroquinolones including garenoxacin. Garenoxacin was four- to eightfold less active against Enterobacteriaceae than ciprofloxacin, although both drugs inhibited similar percentages at 1 microg/ml. Garenoxacin was more active against gram-positive species than all other fluoroquinolones except gemifloxacin. For Staphylococcus aureus, oxacillin resistance was high in many participating countries (Japan, 67%; Taiwan, 60%; Hong Kong, 55%; Singapore, 52%), with corresponding high levels of ciprofloxacin resistance (57 to 99%) in oxacillin-resistant S. aureus (ORSA). Of the ciprofloxacin-resistant ORSA isolates, the garenoxacin MIC was >4 microg/ml for only 9% of them. For Streptococcus pneumoniae, penicillin nonsusceptibility and macrolide resistance were high in many countries. No relationship was seen between penicillin and garenoxacin susceptibility, with all isolates being susceptible at <2 microg/ml. There was, however, a partial correlation between ciprofloxacin and garenoxacin MICs. For ciprofloxacin-resistant isolates for which garenoxacin MICs were 0.25 to 1 microg/liter, mutations in both the ParC and GyrA regions of the quinolone resistance-determining region could be demonstrated. No mutations conferring high-level resistance were detected. Garenoxacin shows useful activity against a wide range of organisms from the Asia-Pacific region. In particular, it has good activity against S. aureus and S. pneumoniae, although there is evidence that low-level resistance is present in those organisms with ciprofloxacin resistance.
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Bell JM. Image-guided spine intervention. By D S Fenton and L F Czervionke, pp. xv + 298, 2003 (W.B. Saunders Co. Ltd, Philadelphia, PA), £120.00 ISBN 0-7216-0021-2. Br J Radiol 2004. [DOI: 10.1259/bjr.77.919.770626b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Bell JM, Turnidge JD, Jones RN. Prevalence of extended-spectrum beta-lactamase-producing Enterobacter cloacae in the Asia-Pacific region: results from the SENTRY Antimicrobial Surveillance Program, 1998 to 2001. Antimicrob Agents Chemother 2004; 47:3989-93. [PMID: 14638518 PMCID: PMC296176 DOI: 10.1128/aac.47.12.3989-3993.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterobacter cloacae strains from hospitalized patients with a range of infections were collected by 17 laboratories in the Asia-Pacific region and South Africa. Isolates for which ceftriaxone MICs were above 1 microg/ml and/or ceftazidime MICs were above 2 microg/ml, as well as 46 strains for which ceftriaxone and/or ceftazidime MICs were at or below these values, were screened for levels of extended-spectrum beta-lactamase (ESBL) production through the use of broth microdilution for the detection of clavulanate enhancement of the activity of ceftriaxone, ceftazidime, and cefepime. Of the isolates examined, ceftriaxone and/or ceftazidime had elevated MICs for 44%, of which 36% were ESBL positive. ESBL-positive strains were commonly susceptible to piperacillin-tazobactam and more frequently resistant to several other antimicrobials studied. A cefepime MIC above 0.25 microg/ml had the highest sensitivity (100%) and specificity (74%) for predicting the presence of an ESBL.
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Affiliation(s)
- J M Bell
- Microbiology and Infectious Diseases Department, Women's and Children's Hospital, Adelaide, Australia.
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Abstract
Pollinators often visit several flowers in sequence on plants with large floral displays. This foraging pattern is expected to influence the rate of self-fertilization in self-compatible taxa. To quantify the effects of daily floral display on pollinator movements and selfing, we experimentally manipulated flower number in four replicate (cloned) arrays of Mimulus ringens (Scrophulariaceae), each consisting of genets with unique combinations of homozygous marker genotypes. Four display classes (two, four, eight and 16 flowers) were present in each array. Pollinator visitation rate per flower and seed set per fruit were unaffected by display. However, flower number strongly influenced the frequency of within-plant pollinator movements, which increased from 13.8% of probes on two-flower displays to 77.6% of probes on 16-flower displays. The proportion of within-plant movements was significantly correlated with selfing (r = 0.993). The increase from 22.9% selfing on two-flower displays to 37.3% selfing on 16-flower displays reflects changes in the extent of geitonogamous self-pollination. We estimate that approximately half of all selfing on 16-flower displays resulted from geitonogamy. Selfing also varied dramatically among fruits within display classes. Nested ANOVA indicates that differences among flowers on two-flower ramets accounted for 45.4% of the variation in selfing, differences among genets accounted for 16.1% of the variation, and statistical and sampling error accounted for 38.5% of the variation. Differences among flowers within ramets may reflect the order of sequential floral probes on a display.
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Affiliation(s)
- J D Karron
- Department of Biological Sciences, PO Box 413, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
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Basselin M, Chang L, Seemann R, Bell JM, Rapoport SI. Chronic lithium administration potentiates brain arachidonic acid signaling at rest and during cholinergic activation in awake rats. J Neurochem 2003; 85:1553-62. [PMID: 12787074 DOI: 10.1046/j.1471-4159.2003.01811.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Studies were performed to determine if the reported 'proconvulsant' action of lithium in rats given cholinergic drugs is related to receptor-initiated phospholipase A2 signaling via arachidonic acid. Regional brain incorporation coefficients k* of intravenously injected [1-14C]arachidonic acid, which represent this signaling, were measured by quantitative autoradiography in unanesthetized rats at baseline and following administration of subconvulsant doses of the cholinergic muscarinic agonist, arecoline. In rats fed LiCl for 6 weeks to produce a therapeutically relevant brain lithium concentration, the mean baseline values of k* in brain auditory and visual areas were significantly greater than in rats fed control diet. Arecoline at doses of 2 and 5 mg/kg intraperitoneally increased k* in widespread brain areas in rats fed the control diet as well as the LiCl diet. However, the arecoline-induced increments often were significantly greater in the LiCl-fed than in the control diet-fed rats. Lithium's elevation of baseline k* in auditory and visual regions may correspond to its ability in humans to increase auditory and visual evoked responses. Additionally, its augmentation of the k* responses to arecoline may underlie its reported 'proconvulsant' action with cholinergic drugs, as arachidonic acid and its eicosanoid metabolites can increase neuronal excitability and seizure propagation.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Bell JM, Turnidge JD, Jones RN. Antimicrobial resistance trends in community-acquired respiratory tract pathogens in the Western Pacific Region and South Africa: report from the SENTRY antimicrobial surveillance program, (1998-1999) including an in vitro evaluation of BMS284756. Int J Antimicrob Agents 2002; 19:125-32. [PMID: 11850165 DOI: 10.1016/s0924-8579(01)00475-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
From 1998 to 1999, a large number of community-acquired respiratory tract isolates of Streptococcus pneumoniae (n=566), Haemophilus influenzae (n=513) and Moraxella catarrhalis (n=228) were collected from 15 centres in Australia, Hong Kong, Japan, China, the Philippines, Singapore, South Africa and Taiwan through the SENTRY Antimicrobial Surveillance Program. Isolates were tested against 26 antimicrobial agents using the NCCLS-recommended methods. Overall, 40% of S. pneumoniae isolates were resistant to penicillin with 18% of strains having high-level resistance (MIC > or =2 mg/l). Rates of erythromycin and clindamycin resistance were 41 and 23%, respectively. Penicillin-resistant strains showed high rates of resistance to other antimicrobial agents: 96% to trimethoprim-sulphamethoxazole (TMP-SMX), 84% to tetracycline and 81% to erythromycin. A significant proportion of penicillin-susceptible strains was also resistant to erythromycin (21%), tetracycline (29%) and TMP-SMZ (26%). Small numbers of strains were resistant to levofloxacin (0.7%), trovafloxacin (0.4%) and grepafloxacin (1.3%) where as all strains remained uniformly susceptible to quinupristin/dalfopristin and BMS284756 (MIC(90), 0.06 mg/l), a new desfluoroquinolone. beta-lactamases were, produced by 20% H. influenzae isolates and only rare strains showed intrinsic resistance to amoxycillin. Other beta-lactam agents showed good activity with rates of resistance less than 2% and all isolates showed susceptibility to cefixime, ceftibuten, cefepime and cefotaxime. Rates of resistance to tetracycline and chloramphenicol were also relatively low at 3%. The majority (98%) of M. catarrhalis isolates was found to be beta-lactamase-positive and resistant to penicillins, however, resistance to erythromycin and tetracycline was also low at 1.8%. Both H. influenzae and M. catarrhalis isolates were uniformly susceptible to the new desfluoroquinolone and tested fluoroquinolones.
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Bosetti F, Seemann R, Bell JM, Zahorchak R, Friedman E, Rapoport SI, Manickam P. Analysis of gene expression with cDNA microarrays in rat brain after 7 and 42 days of oral lithium administration. Brain Res Bull 2002; 57:205-9. [PMID: 11849827 DOI: 10.1016/s0361-9230(01)00744-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The gene expression profile in rat brain was examined using microarrays in rats fed lithium chloride for 7 days (subacute) or 42 days (chronic). Brain lithium concentrations were 0.39 mM and 0.79 mM (therapeutically relevant), at 7 and 42 days, respectively. Of the 4132 genes represented in the microarrays, 25 genes were downregulated by at least twofold and none was upregulated after 7 days of treatment. Expression of 50 genes was downregulated by at least two-fold at 42 days, without any being upregulated. Lithium treatment for 7 days did not affect at a measurable extent expression of 37 of the 50 genes that were downregulated at 42 days. Genes whose expression was changed at 42 days coded for a number of receptors, protein kinases, transcription and translation factors, markers of energy metabolism, and signal transduction. Thus, chronic lithium at a therapeutically relevant concentration reduced expression of a large number of genes involved in multiple signaling and other pathways, without increasing expression at a comparable extent.
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Affiliation(s)
- Francesca Bosetti
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, 9000 Rockville Pike, Building 10, Room 6N202, Bethesda, MD 20892, USA.
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Abstract
OBJECTIVE To determine whether weekly fructosamine testing at home by patients with type 2 diabetes, combined with therapeutic intervention when necessary on the basis of the results, would lead to improved glycemic control in comparison with usual care during a 3-month period. METHODS In a prospective study, 25 patients with glycosylated hemoglobin (HbA1c) values above 8.0% were randomized into 2 groups. Both groups, a glucose-only testing group (14 patients with an initial mean HbA1c of 9.4 +/- 0.9%) and a combined glucose plus fructosamine testing group (11 patients with an initial mean HbA1c of 9.2 +/- 0.7%), received therapeutic intervention at the time of randomization. Both groups were instructed to perform blood glucose testing up to four times per day. The combined glucose plus fructosamine testing group was also instructed to perform weekly fructosamine testing in addition to the glucose testing and to telephone the investigator if their home-testing fructosamine value exceeded 350 mmol/L (approximately equivalent to HbA1c of 7.8%), whereupon the investigator implemented further interventions. Both groups returned in 3 months, at which time HbA1c testing was repeated in order to determine whether glycemic control had changed. RESULTS The study results after 3 months showed that the HbA1c values in the combined glucose plus fructosamine testing group decreased from 9.2 +/- 0.7% to 8.0 +/- 0.5% (P<0.0001). In contrast, the HbA1c values in the glucose-only testing group declined from 9.4 +/- 0.9% to 9.1 +/- 1.3%, a difference that was not significant. CONCLUSION In the 3 months after a change in therapy for type 2 diabetes, weekly home testing of fructosamine, combined with therapeutic interventions based on the results, led to a more rapid and significant improvement in glycemic control than did the usual regimen of glucose-only testing.
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Affiliation(s)
- S V Edelman
- Section of Diabetes and Metabolism, San Diego Veterans Affairs Medical Center, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
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Plank SM, Copeland-Yates SA, Sossey-Alaoui K, Bell JM, Schroer RJ, Skinner C, Michaelis RC. Lack of association of the (AAAT)6 allele of the GXAlu tetranucleotide repeat in intron 27b of the NF1 gene with autism. Am J Med Genet 2001; 105:404-5. [PMID: 11449390 DOI: 10.1002/ajmg.1432] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A novel allele of the GXAlu tetranucleotide repeat in intron 27b of the neurofibromatosis 1 (NF1) gene has recently been reported to be present in 4.7% of autistic patients but not in controls. We have found the novel GXAlu allele absent in 204 patients from the South Carolina Autism Project and 200 controls. The autism population studied includes a significant number of patients with hypotonia, stereotyped behaviors, or postural, gait, and motor abnormalities similar to those seen in the patients previously reported to possess the novel GXAlu allele. This suggests that the novel (AAAT)6 GXAlu allele is not associated with autism.
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Affiliation(s)
- S M Plank
- Presbyterian College, Clinton, South Carolina, USA
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Chang MC, Contreras MA, Rosenberger TA, Rintala JJ, Bell JM, Rapoport SI. Chronic valproate treatment decreases the in vivo turnover of arachidonic acid in brain phospholipids: a possible common effect of mood stabilizers. J Neurochem 2001; 77:796-803. [PMID: 11331408 DOI: 10.1046/j.1471-4159.2001.00311.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Both (Li(+)) and valproic acid (VPA) are effective in treating bipolar disorder, but the pathway by which either works, and whether it is common to both drugs, is not agreed upon. We recently reported, using an in vivo fatty acid model, that Li(+) reduces the turnover rate of the second messenger arachidonic acid (AA) by 80% in brain phospholipids of the awake rat, without changing turnover rates of docosahexaenoic or palmitic acid. Reduced AA turnover was accompanied by down-regulation of gene expression and protein levels of an AA-specific cytosolic phospholipase A(2) (cPLA(2)). To see if VPA had the same effect on AA turnover, we used our in vivo fatty acid model in rats chronically administered VPA (200 mg/kg, i.p. for 30 days). Like Li(+), VPA treatment significantly decreased AA turnover within brain phospholipids (by 28-33%), although it had no effect on cPLA(2) protein levels. Thus, both mood stabilizers, Li(+) and VPA have a common action in reducing AA turnover in brain phospholipids, albeit by different mechanisms.
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Affiliation(s)
- M C Chang
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892-7965, USA.
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Abstract
Australia has a long association methicillin-resistant Staphylococcus aureus (MRSA). Its unique geographic and demographic features have led to the emergence and spread of three types of MRSA over 35 years. Classical multiresistant hospital-acquired MRSA were first noted in Australia in 1965. By the end of the 1970s, strains of this type of MRSA were well established in the complex tertiary care hospitals in the capital cities on the eastern seaboard of mainland Australia. Characterized by resistance to beta-lactams, erythromycin, tetracycline, gentamicin, and trimethoprim-sulfamethoxazole, these strains have persisted and diversified genetically and have acquired a variety of new resistances. They have proven pathogenicity and are a prominent cause of hospital infection in the endemic institutions. More recently they have become endemic in some central state tertiary care hospitals. Community-acquired strains of MRSA first appeared in the north of Western Australia in the mid-1980s. Strains have subsequently appeared in the south of the state and in the two adjacent central states, and are more frequently isolated from Aboriginal patients. Although harboring few or no additional resistances apart from resistance to beta-lactams initially, these strains are also accumulating additional resistances. A different variety of community-acquired MRSA has recently been noted in eastern Australia. It has a similar antibiogram to the western strains, but an entirely different epidemiology, resembling that currently being experienced in parts of New Zealand, and associated with patients of south Pacific island origin.
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Affiliation(s)
- J D Turnidge
- Department of Microbiology and Infectious Diseases, Women's and Children's Hospital, North Adelaide, South Australia, Australia.
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