23801
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Norris CM, Blalock EM, Chen KC, Porter NM, Landfield PW. Calcineurin enhances L-type Ca(2+) channel activity in hippocampal neurons: increased effect with age in culture. Neuroscience 2002; 110:213-25. [PMID: 11958864 PMCID: PMC1473990 DOI: 10.1016/s0306-4522(01)00574-7] [Citation(s) in RCA: 69] [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: 10/18/2022]
Abstract
The Ca(2+)/calmodulin-dependent protein phosphatase, calcineurin, modulates a number of key Ca(2+) signaling pathways in neurons, and has been implicated in Ca(2+)-dependent negative feedback inactivation of N-methyl-D-aspartate receptors and voltage-sensitive Ca(2+) channels. In contrast, we report here that three mechanistically disparate calcineurin inhibitors, FK-506, cyclosporin A, and the calcineurin autoinhibitory peptide, inhibited high-voltage-activated Ca(2+) channel currents by up to 40% in cultured hippocampal neurons, suggesting that calcineurin acts to enhance Ca(2+) currents. This effect occurred with Ba(2+) or Ca(2+) as charge carrier, and with or without intracellular Ca(2+) buffered by EGTA. Ca(2+)-dependent inactivation of Ca(2+) channels was not affected by FK-506. The immunosuppressant, rapamycin, and the protein phosphatase 1/2A inhibitor, okadaic acid, did not decrease Ca(2+) channel current, showing specificity for effects on calcineurin. Blockade of L-type Ca(2+) channels with nimodipine fully negated the effect of FK-506 on Ca(2+) channel current, while blockade of N-, and P-/Q-type Ca(2+) channels enhanced FK-506-mediated inhibition of the remaining L-type-enriched current. FK-506 also inhibited substantially more Ca(2+) channel current in 4-week-old vs. 2-week-old cultures, an effect paralleled by an increase in calcineurin A mRNA levels. These studies provide the first evidence that calcineurin selectively enhances L-type Ca(2+) channel activity in neurons. Moreover, this action appears to be increased concomitantly with the well-characterized increase in L-type Ca(2+) channel availability in hippocampal neurons with age-in-culture.
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Key Words
- protein phosphatase
- aging
- ca2+ channel currents
- fk-506
- cyclosporin a
- nimodipine
- conotoxins
- anova, analysis of variance
- [ca2+]i,intracellular ca2+ concentration
- cn-aip, calcineurin autoinhibitory peptide
- cnqx, 6-cyano-7-nitroquinoxaline-2,3-dione disodium
- csa, cyclosporin a
- div, days in vitro
- edta, ethylene glycol-bis(2-aminoethyl-ether)-n,n,n′,n′-tetraacetic acid
- fkbp-12, fk-506-binding protein 12
- hepes, n-(2-hydroxyethyl)pipera-zine-n′-(2-ethanesulphonic acid)
- hva, high-voltage activated
- hplc, high-performance liquid chromatography
- nmdar, n-methyl-d-aspartate receptor
- pcr, polymerase chain reaction
- rt, reverse transcription
- tea, tetraethylammonium
- vscc., voltage-sensitive ca2+ channel
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Affiliation(s)
- C M Norris
- Department of Molecular and Biomedical Pharmacology, College of Medicine, MS-310 UKMC, University of Kentucky, Lexington, KY 40536-0298, USA.
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23802
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Vink A, Schoneveld AH, Poppen M, de Kleijn DPV, Borst C, Pasterkamp G. Morphometric and immunohistochemical characterization of the intimal layer throughout the arterial system of elderly humans. J Anat 2002; 200:97-103. [PMID: 11837253 PMCID: PMC1570889 DOI: 10.1046/j.0021-8782.2001.00005.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The purpose of the present study was to obtain insight into the natural development of adaptive intimal thickening and atherosclerosis in the arterial tree of human species. The morphometry and composition of the intimal layer were studied in the arterial system of elderly individuals. Post mortem, a total of 703 arterial segments were dissected from 24 subjects (age 81.9 +/- 9.9 years). From each subject, segments were dissected from 31 different arteries. Area stenosis [(plaque area/vessel area) x 100%] was determined in each segment. By (immuno)histochemistry, lipid content and the presence of inflammatory cells (macrophages) were assessed in the coronary, common carotid, brachial, radial and internal iliac arteries. Adaptive intimal thickening or advanced atherosclerosis was observed in all studied artery types. Area stenosis was highest in the coronary arteries (median, 30%) and lowest in the arteries supplying the brain (median, < or = 7%). Plaques hiding a lipid-rich core and plaques with macrophage infiltration were observed in all five selected artery types. In summary, the present observation demonstrates that intimal thickening is a systemic process involving most artery types. Within elderly humans, features of advanced atherosclerotic disease, a lipid-rich core and macrophages, can be observed in the intimal layer of artery types that are recognised for their relation with clinical syndroms as well as artery types that remain clinically silent.
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Affiliation(s)
- Aryan Vink
- Department of Cardiology, Heart Lung Institute, University Medical Center UtrechtThe Netherlands
- Interuniversity Cardiology Institute of The NetherlandsUtrecht, The Netherlands
| | - Arjan H Schoneveld
- Department of Cardiology, Heart Lung Institute, University Medical Center UtrechtThe Netherlands
- Interuniversity Cardiology Institute of The NetherlandsUtrecht, The Netherlands
| | - Marieke Poppen
- Department of Cardiology, Heart Lung Institute, University Medical Center UtrechtThe Netherlands
- Interuniversity Cardiology Institute of The NetherlandsUtrecht, The Netherlands
| | - Dominique PV de Kleijn
- Department of Cardiology, Heart Lung Institute, University Medical Center UtrechtThe Netherlands
- Interuniversity Cardiology Institute of The NetherlandsUtrecht, The Netherlands
| | - Cornelius Borst
- Department of Cardiology, Heart Lung Institute, University Medical Center UtrechtThe Netherlands
| | - Gerard Pasterkamp
- Department of Cardiology, Heart Lung Institute, University Medical Center UtrechtThe Netherlands
- Interuniversity Cardiology Institute of The NetherlandsUtrecht, The Netherlands
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23803
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Spindler SR. Reversing the negative genomic effects of aging with short-term calorie restriction. ScientificWorldJournal 2001; 1:544-6. [PMID: 12805847 PMCID: PMC6084508 DOI: 10.1100/tsw.2001.256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
According to government figures, total health care spending in the U.S. in 1999 was 1.316 trillion dollars. The government projects an increase in health care costs to 2.176 trillion dollars by 2008. If we project this growth rate to 2020, health care costs will reach 4.009 trillion dollars. Today, people often spend more health care dollars during the last year of their lives than in all previous years combined. Medical treatment in the last few years of life is usually very expensive and often futile. With the baby-boom generation now moving through middle age, the prescription for the U.S. health care system will be disastrous unless we learn how to keep people healthier longer. This dramatic increase in health care costs leaves us with only one acceptable alternative to rationed health care or financial ruin--to discover interventions that make people functionally younger, healthier, and less susceptible to debilitating, age-related diseases.
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Affiliation(s)
- S R Spindler
- Department of Biochemistry, University of California, Riverside, Riverside, CA 92521, USA.
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23804
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Abstract
Immunization induces less protective immunity against infectious diseases in old compared to young subjects. We have studied the effect of age on the in vitro and in vivo function of murine transgenic T cells expressing a receptor for influenza hemagglutinin 110-120 peptide. During aging the transgenic T cells undergo the age-associated shift from naive to memory phenotype but maintain, despite thymic involution, their number as well as their cytokine production and proliferative responses induced by the hemagglutinin 110-120 peptide in vitro. The maintenance of the size and functions of transgenic T cells during the aging may be related to low expression of CTLA-4 molecules known to exhibit a negative regulatory effect subsequent to interaction with costimulatory molecules as well as of stimulation of T cells by unknown cross reactive endogenous factors but not by nominal antigen since innate immunity prevents natural infection with influenza virus of murine species. This suggests that the impaired immunity induced by immunization in old subjects reflects defects in the development and maintenance of T cell memory and not in the expression of effector activity.
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MESH Headings
- Aging/immunology
- Animals
- Female
- Hemagglutinin Glycoproteins, Influenza Virus/immunology
- Hemagglutinin Glycoproteins, Influenza Virus/metabolism
- Interferon-gamma/metabolism
- Interleukin-4/metabolism
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Orthomyxoviridae/metabolism
- Peptides/immunology
- Peptides/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Spleen/cytology
- Survival Rate
- T-Lymphocytes/immunology
- T-Lymphocytes/physiology
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Affiliation(s)
- D L Radu
- Dept. of Microbiology, Mount Sinai School of Medicine, 1 Gustave L. Levy Pl., New York, NY 10029, USA
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23805
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Abstract
Presbycusis is a complex of high frequency hearing loss and disproportionate loss of speech discrimination that is seen concomitantly with physical signs of aging. Among the most extensively characterized strains of mice that show an early hearing loss is the C57B16/J strain, a strain that shows early onset of high frequency hearing loss at age 6 months and complete hearing loss by 1 year of age. The histopathology of this strain consists of loss of hair cells and spiral ganglion neurons in the basal turn, with a progression of loss of hair cells and ganglion neurons towards the apical portion of the cochlea as the animal ages. The process of aging has been extensively studied and although details differ in various organisms the consensus today is that oxidative stress, i.e. free radical-mediated tissue damage, is one of the core mechanisms of aging. Aerobic metabolism results in the creation of hydrogen peroxide and reactive oxygen species. These are normally detoxified by a variety of enzymes and free radical scavengers, including superoxide dismutase (SOD), catalase and glutathione. To determine whether oxidative stress plays a role in the pathophysiology of hearing loss in this mouse model of presbycusis we determined the relative change in mRNA production for selected free radical detoxifying enzymes in the C57B16/J mouse cochlea. Using semi-quantitative RT-PCR with tubulin mRNA as a control, relative levels of antioxidant enzyme mRNAs were determined. There was an overall increase in SOD1 mRNA levels when comparing 1 and 9 month time points, and a transient increase in the expression level of catalase mRNA. B6.CAST+ Ahl mice, which carry the C57B16/J genome but receive their Ahl gene from CAST mice, do not show these alteractions in antioxidant enzyme production. Our results suggest that at an age of 9 months, at which point significant hearing loss has developed, the C57B16/J mouse cochlea is exposed to increased levels of free radicals and that the Ahl gene of the C57B16/J mouse mediates this decrease in protective enzymes and therefore increase in levels of oxidative stress.
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Affiliation(s)
- H Staecker
- Division of Otolaryngology, University of Maryland Medical School, Baltimore, Maryland 21201-1619, USA.
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23806
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Scriabine A. Alzheimer's disease, cancer and the search for a better aspirin. Postgraduate course at Mount Sinai School of Medicine, New York, NY June 22-23, 2001. CNS Drug Rev 2001; 7:346-52. [PMID: 11775585 PMCID: PMC6494139 DOI: 10.1111/j.1527-3458.2001.tb00203.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A Scriabine
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06420, USA
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23807
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Starkstein SE. Cerebral aging: neuropsychological, neuroradiological, and neurometabolic correlates. Dialogues Clin Neurosci 2001; 3:217-28. [PMID: 22034198 PMCID: PMC3181656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The aging process is associated with a progressive cognitive decline, but both the extent of this decline and the profile of age-related cognitive changes remain to be clearly established. Currently, cognitive deficits associated with aging may be diagnosed under the categories of age-associated memory impairment, age-associated cognitive impairment, or the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) category of age-related cognitive decline. Age-related decline has been reported for several cognitive domains, such as language (eg, verb naming, verbal fluency), visuospatial abilities (eg, facial discrimination), executive functions (eg, set shifting, problem solving), and memory functions (eg, declarative learning, source memory). There is an age-related decline in brain cortical volume, which primarily involves association cortices and limbic regions. Studies of brain metabolic activity demonstrate an age-related decline in neocortical areas. Activation studies using cognitive tasks demonstrate that older healthy individuals have a different pattern of activation from younger subjects, suggesting thai older subjects may recruit additional brain areas in order to maintain performance.
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Affiliation(s)
- Sergio E. Starkstein
- Department of Neuropsychiatry and Neuropsychology, Raul Carrea Institute of Neurological Research-FLENI, Buenos Aires, Argentina
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23808
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Reich EE, Montine KS, Gross MD, Roberts LJ, Swift LL, Morrow JD, Montine TJ. Interactions between apolipoprotein E gene and dietary alpha-tocopherol influence cerebral oxidative damage in aged mice. J Neurosci 2001; 21:5993-9. [PMID: 11487622 PMCID: PMC6763161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
Cerebral oxidative damage is a feature of aging and is increased in a number of neurodegenerative diseases. We pursued the gene-environment interaction of lack of apolipoprotein E (apoE) and modulation of dietary alpha-tocopherol on cerebral oxidative damage in aged male and female mice by quantifying the major isomers of cerebral isoprostanes, derived from arachidonic acid (AA) oxidation, and neuroprostanes, derived from docosahexaenoic acid (DHA) oxidation. Mice fed alpha-tocopherol-deficient, normal, or -supplemented diet had undetectable, 4486 +/- 215, or 6406 +/- 254 ng of alpha-tocopherol per gram of brain tissue (p < 0.0001), respectively. Two factors, male gender and lack of apoE, combined to increase cerebral AA oxidation by 28%, whereas three factors, male gender, lack of apoE, and deficiency in alpha-tocopherol, combined to increase cerebral DHA oxidation by 81%. alpha-Tocopherol supplementation decreased cerebral isoprostanes but not neuroprostanes and enhanced DHA, but not AA, endoperoxide reduction in vivo and in vitro. These results demonstrated that the interaction of gender, inherited susceptibilities, and dietary alpha-tocopherol contributed differently to oxidative damage to cerebral AA and DHA in aged mice.
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Affiliation(s)
- E E Reich
- Departments of Pathology, Medicine, and Pharmacology and Center for Molecular Neurosciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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23809
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Abstract
This paper develops a method for appraising health status in elderly people. A frailty index was defined as the proportion of accumulated deficits (symptoms, signs, functional impairments, and laboratory abnormalities). It serves as an individual state variable, reflecting severity of illness and proximity to death. In a representative database of elderly Canadians we found that deficits accumulated at 3% per year, and show a gamma distribution, typical for systems with redundant components that can be used in case of failure of a given subsystem. Of note, the slope of the index is insensitive to the individual nature of the deficits, and serves as an important prognostic factor for life expectancy. The formula for estimating an individual's life span given the frailty index value is presented. For different patterns of cognitive impairments the average within-group index value increases with the severity of the cognitive impairment, and the relative variability of the index is significantly reduced. Finally, the statistical distribution of the frailty index sharply differs between well groups (gamma distribution) and morbid groups (normal distribution). This pattern reflects an increase in uncompensated deficits in impaired organisms, which would lead to illness of various etiologies, and ultimately to increased mortality. The accumulation of deficits is as an example of a macroscopic variable, i.e., one that reflects general properties of aging at the level of the whole organism rather than any given functional deficiency. In consequence, we propose that it may be used as a proxy measure of aging.
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Affiliation(s)
- A B Mitnitski
- Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec H3C 3A7.
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23810
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Abstract
Females are expected to have different mating preferences because of the variation in costs and benefits of mate choice both between females and within individual females over a lifetime. Workers have begun to look for, and find, the expected variation among females in expressed mating preferences. However, variation within females caused by changes in intrinsic influences has not been examined in detail. Here we show that reproductive aging caused by delayed mating resulted in reduced choosiness by female Nauphoeta cinerea, a cockroach that has reproductive cycles and gives live birth. Male willingness to mate was unaffected by variation in female age. Females who were beyond the optimal mating age, 6 days postadult molt, required considerably less courtship than their younger counterparts. Females who were older when they mated had fewer offspring per clutch and fewer clutches than females who mated young. Thus, reduced choosiness was correlated with a permanent reduction in fertility. There was no difference in overall senescence among females, and thus the reduction in clutch size did not result in the expected increased lifespan. We suggest that reproductive aging in N. cinerea, similar to aging in general, occurs because the maintenance of oocytes is costly, and selection is relaxed after the optimal mating period. Our results further suggest that selection for continued choosiness is also relaxed and supports direct selection on female choosiness and a cost to choosiness.
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Affiliation(s)
- P J Moore
- School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.
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23811
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Abstract
Bclw is a death-protecting member of the Bcl2 family of apoptosis-regulating proteins. Mice that are mutant for Bclw display progressive and nearly complete testicular degeneration. We performed a morphometric evaluation of testicular histopathology in Bclw-deficient male mice between 9 days postnatal (p9) through 1 yr of age. Germ cell loss began by p22, with only few germ cells remaining beyond 7 mo of age. A complete block to elongated spermatid development at step 13 occurred during the first wave of spermatogenesis, whereas other types of germ cells were lost sporadically. Depletion of Sertoli cells commenced between p20 and p23 and continued until 1 yr of age, when few, if any, Sertoli cells remained. Mitochondria appeared to be swollen and the cytoplasm dense by electron microscopy, but degenerating Bclw-deficient Sertoli cells failed to display classical features of apoptosis, such as chromatin condensation and nuclear fragmentation. Macrophages entered seminiferous tubules and formed foreign-body giant cells that engulfed and phagocytosed the degenerated Sertoli cells. Leydig cell hyperplasia was evident between 3 and 5 mo of age. However, beginning at 7 mo of age, Leydig cells underwent apoptosis, with dead cells being phagocytosed by macrophages. The aforementioned cell losses culminated in a testis-containing vasculature, intertubular phagocytic cells, and peritubular cell "ghosts." An RNA in situ hybridization study indicates that Bclw is expressed in Sertoli cells in the adult mouse testis. Consequently, the diploid germ cell death may be an indirect effect of defective Sertoli cell function. Western analysis was used to confirm that Bclw is not expressed in spermatids; thus, loss of this cell type most likely results from defective Sertoli cell function. Because Bclw does not appear to be expressed in Leydig cells, loss of Leydig cells in Bclw-deficient mice may result from depletion of Sertoli cells. Bclw-deficient mice serve as a unique model to study homeostasis of cell populations in the testis.
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Affiliation(s)
- Lonnie D. Russell
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901-6512
| | - Jeff Warren
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901-6512
| | - Luciano Debeljuk
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901-6512
| | - Laura L. Richardson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Patryce L. Mahar
- Center for Molecular Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Katrina G. Waymire
- Center for Molecular Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Scott P. Amy
- Center for Molecular Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Andrea J. Ross
- Center for Molecular Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, Georgia 30322
| | - Grant R. MacGregor
- Center for Molecular Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
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23812
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Muir GM, Bilkey DK. Instability in the place field location of hippocampal place cells after lesions centered on the perirhinal cortex. J Neurosci 2001; 21:4016-25. [PMID: 11356888 PMCID: PMC6762702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023] Open
Abstract
The perirhinal cortex appears to play a key role in memory, and the neighboring hippocampus is critically involved in spatial processing. The possibility exists, therefore, that perirhinal-hippocampal interactions are important for spatial memory processes. The purpose of the present study was to investigate the contribution of the perirhinal cortex to the location-specific firing ("place field") of hippocampal complex-spike ("place") cells. The firing characteristics of dorsal CA1 place cells were examined in rats with bilateral ibotenic acid lesions centered on the perirhinal cortex (n = 4) or control surgeries (n = 5) as they foraged in a rectangular environment. The activity of individual place cells was also monitored after a delay period of either 2 min, or 1 or 24 hr, during which time the animal was removed from the environment. Although the perirhinal cortex lesion did not affect the place field size or place cell firing characteristics during a recording session, it was determined that the location of the place field shifted position across the delay period in 36% (10 of 28) of the cells recorded from lesioned animals. In contrast, none of the place cells (0 of 29) recorded from control animals were unstable by this measure. These data indicate that although the initial formation of place fields in the hippocampus is not dependent on perirhinal cortex, the maintenance of this stability over time is disrupted by perirhinal lesions. This instability may represent an erroneous "re-mapping" of the environment and suggests a role for the perirhinal cortex in spatial memory processing.
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Affiliation(s)
- G M Muir
- Department of Psychology, University of Otago, Dunedin, 9001, New Zealand
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23813
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Foster TC, Sharrow KM, Masse JR, Norris CM, Kumar A. Calcineurin links Ca2+ dysregulation with brain aging. J Neurosci 2001; 21:4066-73. [PMID: 11356894 PMCID: PMC1201477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023] Open
Abstract
Brain aging is associated with altered Ca(2+) regulation. However, many Ca(2+) signal transduction mechanisms have not been explored in the aged brain. Here, we report that cytosolic expression and activity of the Ca(2+)-dependent protein phosphatase calcineurin (CaN) increases in the hippocampus during aging. CaN changes were paralleled by increased activation, but not expression, of CaN-regulated protein phosphatase 1 and a reduction in the phosphorylation state of CaN substrates involved in cell survival (i.e., Bcl-2-associated death protein and cAMP response element-binding protein). The age-related increase in CaN activity was not attributable to the inability of CaN to translocate to the membrane and was reduced by blocking L-type Ca(2+) channels. Finally, increased CaN activity correlated with memory function as measured with the Morris water escape task. The results suggest that altered regulation of CaN is one of the processes that could link Ca(2+) dyshomeostasis to age-related changes in neural function and cognition.
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Affiliation(s)
- T C Foster
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, College of Medicine, Lexington, Kentucky 40536, USA.
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23814
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Schuff N, Ezekiel F, Gamst AC, Amend DL, Capizzano AA, Maudsley AA, Weiner MW. Region and tissue differences of metabolites in normally aged brain using multislice 1H magnetic resonance spectroscopic im aging. Magn Reson Med 2001; 45:899-907. [PMID: 11323817 PMCID: PMC1851682 DOI: 10.1002/mrm.1119] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [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: 11/06/2022]
Abstract
Quantitative measurements of regional and tissue specific concentrations of brain metabolites were measured in elderly subjects using multislice proton magnetic resonance spectroscopic imaging ((1)H MRSI). Selective k-space extrapolation and an inversion-recovery sequence were used to minimize lipid contamination and linear regression was used to account for partial volume problems. The technique was applied to measure the concentrations of N-acetyl aspartate (NAA), and creatine (Cr)- and choline (Cho)-containing compounds in cortical gray and white matter, and white matter lesions of the frontal and the parietal lobe in 40 normal elderly subjects (22 females and 18 males, 56-89 years old, mean age 74 +/- 8). NAA was about 15% lower in cortical gray matter and 23% lower in white matter lesions when compared to normal white matter. Cr was 11% higher in cortical gray matter than in white matter, and also about 15% higher in the parietal cortex than in the frontal cortex. Cho was 28% lower in cortical gray matter than in white matter. Furthermore, NAA and Cr changes correlated with age. In conclusion, regional and tissue differences of brain metabolites must be considered in addition to age-related changes when interpreting (1)H MRSI data.
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Affiliation(s)
- N Schuff
- DVA Medical Center, San Francisco, California 94121, USA.
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23815
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Antonicelli R, Gesuita R, Boemi M, Paciaroni E. Random fasting hyperglycemia as cardiovascular risk factor in the elderly: a 6-year longitudinal study. Clin Cardiol 2001; 24:341-4. [PMID: 11303705 PMCID: PMC6655154 DOI: 10.1002/clc.4960240416] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2000] [Accepted: 08/15/2000] [Indexed: 11/11/2022] Open
Abstract
A large body of evidence suggests that diabetes increases the risk of coronary heart disease (CHD), but whether fasting hyperglycemia is associated with a major risk for CHD is still under debate. The aim of the present study was to investigate the role played by fasting hyperglycemia in the development of cardiovascular disease (CVD) in an elderly population when associated with common risk factors for CVD (i.e., hypertension, hypercholesterolemia, smoking, etc). We analyzed a sample of 455 subjects aged > or = 60 years. The risk factors taken into account were systolic and diastolic blood pressure levels, use of antihypertensive drugs, total serum cholesterol, serum triglycerides, and smoking habit. Glycemia was measured at entry on a fasting sample. During the follow-up period (mean 6 years), the occurrence of CVD was monitored (criteria for the occurrence of CVD included total cardiovascular mortality, fatal or nonfatal myocardial infarction, symptomatic coronary heart disease [stable and unstable angina], the need for percutaneous transluminal coronary angioplasty or coronary artery bypass graft, fatal or nonfatal stroke, and transient ischemic attack). A total of 427 subjects completed the follow-up. During this period, 73 subjects (17.10%) developed CVD according to the above criteria. A Cox proportional hazard model was designed to evaluate the contribution of variables in predicting CVD. Relative risks and 95% confidence intervals for CVD were calculated from the regression coefficients to study the association between the risk of developing CVD and predicting variables. We found a relation between occurrence of CVD and fasting hyperglycemia: subjects with fasting glycemia, > 126 mg/dl at enrollment, but without previous clinical diagnosis of diabetes, showed a 2.01 times higher risk than those with fasting glycemia < 126 mg/dl. Hence, random fasting hyperglycemia can predict the occurrence of CVD in elderly subjects.
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Affiliation(s)
- R Antonicelli
- Divisione di Patologia Cardiovascolare ed Ipertensione Arteriosa, INRCA, Ancona, Italy
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23816
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SUH JUNGH, SHIGENO ERICT, MORROW JASOND, COX BRIAN, ROCHA ALMAE, FREI BALZ, HAGEN TORYM. Oxidative stress in the aging rat heart is reversed by dietary supplementation with (R)-(alpha)-lipoic acid. FASEB J 2001; 15:700-6. [PMID: 11259388 PMCID: PMC4696539 DOI: 10.1096/fj.00-0176com] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [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: 01/05/2023]
Abstract
Oxidative stress has been implicated as a causal factor in the aging process of the heart and other tissues. To determine the extent of age-related myocardial oxidative stress, oxidant production, antioxidant status, and oxidative DNA damage were measured in hearts of young (2 months) and old (28 months) male Fischer 344 rats. Cardiac myocytes isolated from old rats showed a nearly threefold increase in the rate of oxidant production compared to young rats, as measured by the rates of 2,7-dichlorofluorescin diacetate oxidation. Determination of myocardial antioxidant status revealed a significant twofold decline in the levels of ascorbic acid (P = 0.03), but not alpha-tocopherol. A significant age-related increase (P = 0.05) in steady-state levels of oxidative DNA damage was observed, as monitored by 8-oxo-2'-deoxyguanosine levels. To investigate whether dietary supplementation with (R)-alpha-lipoic acid (LA) was effective at reducing oxidative stress, young and old rats were fed an AIN-93M diet with or without 0.2% (w/w) LA for 2 wk before death. Cardiac myocytes from old, LA-supplemented rats exhibited a markedly lower rate of oxidant production that was no longer significantly different from that in cells from unsupplemented, young rats. Lipoic acid supplementation also restored myocardial ascorbic acid levels and reduced oxidative DNA damage. Our data indicate that the aging rat heart is under increased mitochondrial-induced oxidative stress, which is significantly attenuated by lipoic acid supplementation.
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Affiliation(s)
- JUNG H. SUH
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
| | - ERIC T. SHIGENO
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
| | - JASON D. MORROW
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - BRIAN COX
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - ALMA E. ROCHA
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
| | - BALZ FREI
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
| | - TORY M. HAGEN
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
- Correspondence: Linus Pauling Institute, Oregon State University, 571 Weniger Hall, Corvallis, OR 97331, USA.
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23817
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Peterson BS, Feineigle PA, Staib LH, Gore JC. Automated measurement of latent morphological features in the human corpus callosum. Hum Brain Mapp 2001; 12:232-45. [PMID: 11241874 PMCID: PMC6871880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Our objective was to develop a novel factor-based analysis of the morphology of the corpus callosum and assess its applicability to the study of normal development, intelligence, and other subject characteristics. The contour of the corpus callosum was defined in the midsagittal planes of the MRI scans of 325 subjects, 6 to 88 years of age. The contours were coregistered, rescaled, and resampled to 50 points that were then entered into a principal components analysis with varimax rotation. The analysis yielded 8 factors for the contours of 138 healthy subjects. A second analysis of contours from 187 subjects in a patient group extracted 8 similar factors. Correlations of factor scores with conventional measures of callosum shape supported the construct validity of the assignment of morphological features to each of the factors. Correlations of factor scores with age, sex, handedness, ventricular volume, and IQ demonstrated the predictive validity of the factor structure and helped to define the neural correlates of these subject characteristics. We conclude that factor-based measures capture latent morphological features of the corpus callosum that are reliable and valid. Future studies will determine whether these novel measures are more closely related to neurobiologically important features of the corpus than are conventional measures of callosum size and shape.
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Affiliation(s)
- B S Peterson
- Yale Child Study Center, Yale University, New Haven, Connecticut 06520, USA.
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23818
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Ramirez RD, Morales CP, Herbert BS, Rohde JM, Passons C, Shay JW, Wright WE. Putative telomere-independent mechanisms of replicative aging reflect inadequate growth conditions. Genes Dev 2001; 15:398-403. [PMID: 11230148 PMCID: PMC312628 DOI: 10.1101/gad.859201] [Citation(s) in RCA: 352] [Impact Index Per Article: 15.3] [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: 11/24/2022]
Abstract
Telomere shortening is the mechanism underlying replicative aging in fibroblasts. A variety of reports now claim that inactivation of the p16(INK4a)/pRB pathway is required in addition to telomere maintenance for the immortalization of cells such as skin keratinocytes and breast epithelial cells. We here show that the premature growth arrest of these cell types can be explained by an inadequate culture environment. Providing mesenchymal/epithelial interactions by cultivating the telomerase-expressing cells on feeder layers avoids the growth arrest associated with increased p16(INK4a). These results do not support a telomere-independent mechanism of replicative aging.
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Affiliation(s)
- R D Ramirez
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9039, USA
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23819
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Conner JM, Darracq MA, Roberts J, Tuszynski MH. Nontropic actions of neurotrophins: subcortical nerve growth factor gene delivery reverses age-related degeneration of primate cortical cholinergic innervation. Proc Natl Acad Sci U S A 2001; 98:1941-6. [PMID: 11172055 PMCID: PMC29361 DOI: 10.1073/pnas.98.4.1941] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2000] [Indexed: 11/18/2022] Open
Abstract
Normal aging is associated with a significant reduction in cognitive function across primate species. However, the structural and molecular basis for this age-related decline in neural function has yet to be defined clearly. Extensive cell loss does not occur as a consequence of normal aging in human and nonhuman primate species. More recent studies have demonstrated significant reductions in functional neuronal markers in subcortical brain regions in primates as a consequence of aging, including dopaminergic and cholinergic systems, although corresponding losses in cortical innervation from these neurons have not been investigated. In the present study, we report that aging is associated with a significant 25% reduction in cortical innervation by cholinergic systems in rhesus monkeys (P < 0.001). Further, these age-related reductions are ameliorated by cellular delivery of human nerve growth factor to cholinergic somata in the basal forebrain, restoring levels of cholinergic innervation in the cortex to those of young monkeys (P = 0.89). Thus, (i) aging is associated with a significant reduction in cortical cholinergic innervation; (ii) this reduction is reversible by growth-factor delivery; and (iii) growth factors can remodel axonal terminal fields at a distance, representing a nontropic action of growth factors in modulating adult neuronal structure and function (i.e., administration of growth factors to cholinergic somata significantly increases axon density in terminal fields). These findings are relevant to potential clinical uses of growth factors to treat neurological disorders.
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Affiliation(s)
- J M Conner
- Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093-0626, USA
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23820
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Abstract
Twenty-four hour circadian activity rhythms and light-exposure levels of 28 older schizophrenia patients (mean age=58years) were examined using an Actillume recorder. Sleep and wake were scored using the algorithm of the ACTION3 software which revealed that the patients slept for 67% of the night and napped for 9% of the day. Patients with more disturbed sleep and less robust circadian rhythms performed more poorly on neuropsychological tests. Patients with higher cognitive functioning and fewer extrapyramidal symptoms were more alert during the day. Few patients were exposed to high levels of illumination during the day, and older age was associated with lower levels of light exposure. Duration of antipsychotic use and higher antipsychotic doses were associated with decreased daytime alertness and less robust circadian activity rhythms. Patients taking antipsychotics were more sleepy both during the day and night than patients not taking antipsychotics. The circadian rhythm disturbances found in these patients did not seem to be due solely to low levels of illumination exposure. Life-style factors, behavioral factors, psychiatric symptoms and medications were likely contributors to the disturbed rhythms. The effects of the sleep disturbances did not seem to be benign. There were strong relationships between sleep and circadian rhythms and functioning.
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Affiliation(s)
- Jennifer Martin
- San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA
| | - Dilip V. Jeste
- Department of Psychiatry, University of California, San Diego, CA, USA
- Department of Psychiatry, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Michael P. Caliguiri
- Department of Psychiatry, University of California, San Diego, CA, USA
- Department of Psychiatry, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Thomas Patterson
- Department of Psychiatry, University of California, San Diego, CA, USA
- Department of Psychiatry, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Robert Heaton
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Sonia Ancoli-Israel
- Department of Psychiatry, University of California, San Diego, CA, USA
- Department of Psychiatry, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
- Corresponding author. Present address: Department of Psychiatry 116A, Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA. Tel.: +1-858- 552-8585, ext. 3828; fax: +1-858-552-7536. (S. Ancoli-Israel)
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23821
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Ashton-Miller JA, Howard D, DeLancey JO. The functional anatomy of the female pelvic floor and stress continence control system. Scand J Urol Nephrol Suppl 2001:1-7; discussion 106-25. [PMID: 11409608 PMCID: PMC1192576 DOI: 10.1080/003655901750174773] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This paper provides an overview of the functional anatomy of the structures responsible for controlling urinary continence under stress. The stress continence control system can be divided into two parts: the system responsible for bladder neck support, and the system responsible for sphincteric closure. Age- and injury-related changes in each of these systems are discussed. Understanding the pathophysiology of incontinence on the anatomical level will help to lead to identification of specific defects, thereby allowing better individualized treatment for the incontinent patient.
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Affiliation(s)
- J A Ashton-Miller
- Department of Biomedical Engineering, University of Michigan, Ann Arbor 48109-2125, USA.
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23822
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Abstract
Electron paramagnetic resonance: a high-resolution tool for muscle physiology. Exerc. Sport Sci. Rev., Vol. 29, No. 1, pp 3-6, 2001. Skeletal muscle function can be altered by changes in protein structure and motion. Electron paramagnetic resonance (EPR) paired with site-directed spin labeling has been used to study the relationships between (a) muscle force and myosin structure and (b) muscle relaxation and Ca-ATPase motion and structure.
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Affiliation(s)
- L V Thompson
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, Minnesota, USA.
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23823
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Della-Maggiore V, Sekuler AB, Grady CL, Bennett PJ, Sekuler R, McIntosh AR. Corticolimbic interactions associated with performance on a short-term memory task are modified by age. J Neurosci 2000; 20:8410-6. [PMID: 11069948 PMCID: PMC6773167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Aging has been associated with a decline in memory abilities dependent on hippocampal processing. We investigated whether the functional interactions between the hippocampus and related cortical areas were modified by age. Young and old subjects' brain activity was measured using positron emission tomography (PET) while they performed a short-term memory task (delayed visual discrimination) in which they determined which of two successively presented sine-wave gratings had the highest spatial frequency. Behavioral performance was equal for the two groups. Partial least squares (PLS) analysis of PET images identified a hippocampal voxel whose activity was similarly correlated with performance across groups. Using this voxel as a seed, a second PLS analysis identified cortical regions functionally connected to the hippocampus. Quantification of the neural interactions with structural equation modeling suggested that a different hippocampal network supported performance in the elderly. Unlike the neural network engaged by the young, which included prefrontal cortex Brodmann's area (BA) 10, fusiform gyrus, and posterior cingulate gyrus, the network recruited by the old included more anterior areas, i.e., dorsolateral prefrontal cortex (BA 9/46), middle cingulate gyrus, and caudate nucleus. Recruitment of a distinct corticolimbic network for visual memory in the elderly suggests that age-related neurobiological deterioration not only results in focal changes but also in the modification of large-scale network operations.
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Affiliation(s)
- V Della-Maggiore
- Rotman Research Institute of Baycrest Centre, Toronto, Ontario M6A 2E1, Canada.
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23824
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Wong TP, Marchese G, Casu MA, Ribeiro-da-Silva A, Cuello AC, De Koninck Y. Loss of presynaptic and postsynaptic structures is accompanied by compensatory increase in action potential-dependent synaptic input to layer V neocortical pyramidal neurons in aged rats. J Neurosci 2000; 20:8596-606. [PMID: 11069968 PMCID: PMC6773180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Reduction in both presynaptic and postsynaptic structures in the aging neocortex may significantly affect functional synaptic properties in this area. To directly address this issue, we combined whole-cell patch-clamp recording of spontaneously occurring postsynaptic currents (PSCs) with morphological analysis of layer V pyramidal neurons in the parietal cortex of young adult (1- to 2-month-old) and aged (28- to 37-month-old) BN x F344 F(1) hybrid rats. Analysis of spontaneous PSCs was used to contrast functional properties of basal synaptic input with structural alterations in the dendritic tree of pyramidal neurons and density of terminals in contact with these cells. We observed significant changes in a number of morphological parameters of pyramidal neurons in aged rats. These include smaller cell body size and fewer basal dendritic branches (but not of oblique dendrites and dendritic tufts) and spines. Ultrastructural analysis also revealed a lower density of presynaptic terminals per unit length of postsynaptic membrane of labeled pyramidal neurons in the aged brain. This reduction in both presynaptic and postsynaptic elements was paralleled by a significant decrease in frequency of tetrodotoxin-insensitive miniature (action potential-independent) PSCs (mPSCs). The frequency of excitatory and inhibitory mPSCs was reduced to the same extent. In contrast, no significant change was observed in the frequency of spontaneous PSCs recorded in absence of tetrodotoxin (sPSCs), indicating an increase in action potential-dependent (frequency(sPSCs) - frequency(mPSCs)) input to pyramidal neurons in the aged group. This functional compensation may explain the lack of drastic loss of spontaneous neuronal activity in normal aging.
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Affiliation(s)
- T P Wong
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada, H3G 1Y6
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23825
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Abstract
BACKGROUND The incidence of syncope increases with age, while aging is also associated with increased arterial wave reflection. HYPOTHESIS The study was undertaken to determine whether increased arterial wave reflection is a predisposing factor of syncope. METHODS We recruited 38 patients (28 men and 10 women, mean age 57.2 +/- 20.3 years, range 17-87 years) with a history of syncope within 6 months of entry. The etiology of syncope was documented for each patient by a complete assessment of vasomotor function and cerebral flow. All patients received a comprehensive echocardiographic evaluation of cardiac structure and function. Carotid augmentation index (AI) was estimated noninvasively with the tonometry technique. The results were compared with those from 54 age- and gender-matched controls. RESULTS The most frequent diagnoses of syncope were postural hypotension (13 patients) and cerebrovascular dysautoregulation (10 patients), and the cause could not be determined in 9 patients. Compared with the control group, the syncope group had a greater AI (20 +/- 21 vs. 10 +/- 15%, p = 0.013). Subgroup analysis of 20 patients aged > 50 years and with the aforementioned diagnoses showed even more striking results: AI, 29 +/- 10 vs. 11 +/- 15%, p < 0.001. The enhanced augmentation in the patients remained when age, systolic blood pressure, height, and heart rate were accounted for. Analysis of the carotid pulse wave suggested that both the timing and intensity of wave reflection were enhanced in patients with a history of syncope compared with controls. CONCLUSIONS Our results support the hypothesis that enhanced arterial wave reflection is associated with the occurrence of syncope, especially in the elderly.
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Affiliation(s)
- C H Chen
- Department of Medicine and Center of Neuroscience, Taipei Veterans General Hospital, Taiwan
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23826
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Lyons DM, Lopez JM, Yang C, Schatzberg AF. Stress-level cortisol treatment impairs inhibitory control of behavior in monkeys. J Neurosci 2000; 20:7816-21. [PMID: 11027246 PMCID: PMC6772868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Most studies of cortisol-induced cognitive impairments have focused on hippocampal-dependent memory. This study investigates a different aspect of cognition in a randomized placebo-controlled experiment with monkeys that were treated with cortisol according to a protocol that simulates a prolonged stress response. Young adult and older adult monkeys were assigned randomly to placebo or chronic treatment with cortisol in a 2 x 2 factorial design (n = 8 monkeys per condition). Inhibitory control of behavior was assessed with a test shown previously in primates to reflect prefrontal cortical dysfunction. Failure to inhibit a specific goal-directed response was evident more often in older adults. Treatment with cortisol increased this propensity in both older and young adult monkeys. Age-related differences in response inhibition were consistent across blocks of repeated test trials, but the treatment effects were clearly expressed only after prolonged exposure to cortisol. Aspects of performance that did not require inhibition were not altered by age or treatment with cortisol, which concurs with effects on response inhibition rather than nonspecific changes in behavior. These findings lend support to related reports that cortisol-induced disruptions in prefrontal dopamine neurotransmission may contribute to deficits in response inhibition and play a role in cognitive impairments associated with endogenous hypercortisolism in humans.
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Affiliation(s)
- D M Lyons
- Department of Psychiatry and Behavioral Science, Stanford University School of Medicine, Stanford, California 94305-5485, USA.
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23827
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Greenwood PM, Sunderland T, Friz JL, Parasuraman R. Genetics and visual attention: selective deficits in healthy adult carriers of the epsilon 4 allele of the apolipoprotein E gene. Proc Natl Acad Sci U S A 2000; 97:11661-6. [PMID: 11027364 PMCID: PMC17257 DOI: 10.1073/pnas.97.21.11661] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [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: 06/13/2000] [Indexed: 11/18/2022] Open
Abstract
The epsilon4 allele of the apolipoprotein E (APOE) gene is associated with altered brain physiology in healthy adults before old age, but concomitant deficits in cognition on standardized tests of cognitive function have not been consistently demonstrated. We hypothesized that sensitive and specific assessment of basic attentional functions that underlie complex cognition would reveal evidence of impairment in otherwise asymptomatic individuals. We found that as early as middle age, nondemented carriers of the varepsilon4 allele of the APOE gene showed deficits when visual attention was spatially directed by cues in tasks of visual discrimination and visual search, in comparison to those without the epsilon4 allele (epsilon2 and epsilon3 carriers). Two component attentional operations were selectively affected: (i) shifting spatial attention following invalid location cues, and (ii) adjusting the spatial scale of attention during visual search. These changes occurred only in the presence of the epsilon4 allele and without decline in other aspects of attention (vigilance), memory, or general cognition. The results show that specific components of visual attention are affected by APOE genotype and that the course of cognitive aging is subject to selective alteration by a genetic trait.
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Affiliation(s)
- P M Greenwood
- Cognitive Science Laboratory, Catholic University of America, Washington, DC 20064, USA
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23828
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Dewachter I, Van Dorpe J, Smeijers L, Gilis M, Kuipéri C, Laenen I, Caluwaerts N, Moechars D, Checler F, Vanderstichele H, Van Leuven F. Aging increased amyloid peptide and caused amyloid plaques in brain of old APP/V717I transgenic mice by a different mechanism than mutant presenilin1. J Neurosci 2000; 20:6452-8. [PMID: 10964951 PMCID: PMC6772965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Aging of transgenic mice that overexpress the London mutant of amyloid precursor protein (APP/V717I) (Moechars et al., 1999a) was now demonstrated not to affect the normalized levels of alpha- or beta-cleaved secreted APP nor of the beta-C-terminal stubs. This indicated that aging did not markedly disturb either alpha- or beta-secretase cleavage of APP and failed to explain the origin of the massive amounts of amyloid peptides Abeta40 and Abeta42, soluble and precipitated as amyloid plaques in the brain of old APP/V717I transgenic mice. We tested the hypothesis that aging acted on presenilin1 (PS1) to affect gamma-secretase-mediated production of amyloid peptides by comparing aged APP/V717I transgenic mice to double transgenic mice coexpressing human PS1 and APP/V717I. In double transgenic mice with mutant (A246E) but not wild-type human PS1, brain amyloid peptide levels increased and resulted in amyloid plaques when the mice were only 6-9 months old, much earlier than in APP/V717I transgenic mice (12-15 months old). Mutant PS1 increased mainly brain Abeta42 levels, whereas in aged APP/V717I transgenic mice, both Abeta42 and Abeta40 increased. This resulted in a dramatic difference in the Abeta42/Abeta40 ratio of precipitated or plaque-associated amyloid peptides, i.e., 3.11+/-0.22 in double APP/V717I x PS1/A246E transgenic mice compared with 0.43 +/- 0.07 in aged APP/V717I transgenic mice, and demonstrated a clear difference between the effect of aging and the effect of the insertion of a mutant PS1 transgene. In conclusion, we demonstrate that aging did not favor amyloidogenic over nonamyloidogenic processing of APP, nor did it exert a mutant PS1-like effect on gamma-secretase. Therefore, the data are interpreted to suggest that parenchymal and vascular accumulation of amyloid in aging brain resulted from failure to clear the amyloid peptides rather than from increased production.
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Affiliation(s)
- I Dewachter
- Experimental Genetics Group, Center for Human Genetics, Flemish Institute for Biotechnology, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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23829
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Smith TD, Adams MM, Gallagher M, Morrison JH, Rapp PR. Circuit-specific alterations in hippocampal synaptophysin immunoreactivity predict spatial learning impairment in aged rats. J Neurosci 2000; 20:6587-93. [PMID: 10964964 PMCID: PMC6772954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2000] [Revised: 06/05/2000] [Accepted: 06/06/2000] [Indexed: 02/17/2023] Open
Abstract
The present study examined the long-standing concept that changes in hippocampal circuitry contribute to age-related learning impairment. Individual differences in spatial learning were documented in young and aged Long-Evans rats by using a hippocampal-dependent version of the Morris water maze. Postmortem analysis used a confocal laser-scanning microscopy method to quantify changes in immunofluorescence staining for the presynaptic vesicle glycoprotein, synaptophysin (SYN), in the principal relays of hippocampal circuitry. Comparisons based on chronological age alone failed to reveal a reliable difference in the intensity of SYN staining in any region that was examined. In contrast, aged subjects with spatial learning deficits displayed significant reductions in SYN immunoreactivity in CA3 lacunosum-moleculare (LM) relative to either young controls or age-matched rats with preserved learning. SYN intensity values for the latter groups were indistinguishable. In addition, individual differences in spatial learning capacity among the aged rats correlated with levels of SYN staining selectively in three regions: outer and middle portions of the dentate gyrus molecular layer and CA3-LM. The cross-sectional area of SYN labeling, by comparison, was not reliably affected in relation cognitive status. These findings are the first to demonstrate that a circuit-specific pattern of variability in the connectional organization of the hippocampus is coupled to individual differences in the cognitive outcome of normal aging. The regional specificity of these effects suggests that a decline in the fidelity of input to the hippocampus from the entorhinal cortex may play a critical role.
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Affiliation(s)
- T D Smith
- Kastor Neurobiology of Aging Laboratories, Fishberg Research Center for Neurobiology, and Department of Geriatrics and Adult Development, Mount Sinai School of Medicine, New York, New York 10029-6574, USA
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23830
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Jack CR, Petersen RC, Xu Y, O'Brien PC, Smith GE, Ivnik RJ, Boeve BF, Tangalos EG, Kokmen E. Rates of hippocampal atrophy correlate with change in clinical status in aging and AD. Neurology 2000; 55:484-89. [PMID: 10953178 PMCID: PMC2724764 DOI: 10.1212/wnl.55.4.484] [Citation(s) in RCA: 646] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The cognitive continuum in the elderly population can be conceptually divided into those who are functioning normally (control subjects), those with a mild cognitive impairment (MCI), and those with probable AD. OBJECTIVES To test the hypothesis that the annualized rates of hippocampal atrophy differ as a function of both baseline and change in clinical group membership (control, MCI, or AD). METHODS The authors identified 129 subjects from the Mayo Clinic AD Research Center/AD Patient Registry who met established criteria for normal control subjects, MCI, or probable AD, both at entry and at the time of a subsequent clinical follow-up evaluation 3 +/- 1 years later. Each subject underwent an MRI examination of the head at the time of the initial assessment and at follow-up clinical assessment; the annualized percentage change in hippocampal volume was computed. Subjects who were classified as controls or patients with MCI at baseline could either remain cognitively stable or could decline to a lower functioning group over the period of observation. RESULTS The annualized rates of hippocampal volume loss for each of the three initial clinical groups decreased progressively in the following order: AD > MC > control. Within the control and MCI groups, those who declined had a significantly greater rate of volume loss than those who remained clinically stable. The mean annualized rates of hippocampal atrophy by follow-up clinical group were: control-stable 1.73%, control-decliner 2.81%, MCI-stable 2.55%, MCI-decliner 3.69%, AD 3. 5%. CONCLUSION Rates of hippocampal atrophy match both baseline cognitive status and the change in cognitive status over time in elderly persons who lie along the cognitive continuum from normal to MCI to AD.
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Affiliation(s)
- C R Jack
- Department of Diagnostic Radiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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23831
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Ashrafi K, Lin SS, Manchester JK, Gordon JI. Sip2p and its partner snf1p kinase affect aging in S. cerevisiae. Genes Dev 2000; 14:1872-85. [PMID: 10921902 PMCID: PMC316829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
For a number of organisms, the ability to withstand periods of nutrient deprivation correlates directly with lifespan. However, the underlying molecular mechanisms are poorly understood. We show that deletion of the N-myristoylprotein, Sip2p, reduces resistance to nutrient deprivation and shortens lifespan in Saccharomyces cerevisiae. This reduced lifespan is due to accelerated aging, as defined by loss of silencing from telomeres and mating loci, nucleolar fragmentation, and accumulation of extrachromosomal rDNA. Genetic studies indicate that sip2Delta produces its effect on aging by increasing the activity of Snf1p, a serine/threonine kinase involved in regulating global cellular responses to glucose starvation. Biochemical analyses reveal that as yeast age, hexokinase activity increases as does cellular ATP and NAD(+) content. The change in glucose metabolism represents a new correlate of aging in yeast and occurs to a greater degree, and at earlier generational ages in sip2Delta cells. Sip2p and Snf1p provide new molecular links between the regulation of cellular energy utilization and aging.
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Affiliation(s)
- K Ashrafi
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110 USA
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23832
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Kantarci K, Jack CR, Xu YC, Campeau NG, O'Brien PC, Smith GE, Ivnik RJ, Boeve BF, Kokmen E, Tangalos EG, Petersen RC. Regional metabolic patterns in mild cognitive impairment and Alzheimer's disease: A 1H MRS study. Neurology 2000; 55:210-7. [PMID: 10908893 PMCID: PMC2771162 DOI: 10.1212/wnl.55.2.210] [Citation(s) in RCA: 360] [Impact Index Per Article: 15.0] [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: 11/15/2022] Open
Abstract
BACKGROUND Mild cognitive impairment (MCI) is a recently described transitional clinical state between normal aging and AD. Assuming that amnestic MCI patients had pathologic changes corresponding to an early phase and probable AD patients to a later phase of the disease progression, the authors could approximate the temporal course of proton MR spectroscopic (1H MRS) alterations in AD with a cross-sectional sampling scheme. METHODS The authors compared 1H MRS findings in the superior temporal lobe, posterior cingulate gyri, and medial occipital lobe in 21 patients with MCI, 21 patients with probable AD, and 63 elderly controls. These areas are known to be involved at different neurofibrillary pathologic stages of AD. RESULTS The N-acetylaspartate (NAA)/creatine (Cr) ratios were significantly lower in AD patients compared to both MCI and normal control subjects in the left superior temporal and the posterior cingulate volumes of interest (VOI) and there were no between-group differences in the medial occipital VOI. Myoinositol (MI)/Cr ratios measured from the posterior cingulate VOI were significantly higher in both MCI and AD patients than controls. The choline (Cho)/Cr ratios measured from the posterior cingulate VOI were higher in AD patients compared to both MCI and control subjects. CONCLUSION These findings suggest that the initial 1H MRS change in the pathologic progression of AD is an increase in MI/Cr. A decrease in NAA/Cr and an increase in Cho/Cr develop later in the disease course.
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Affiliation(s)
- K Kantarci
- Departments of Diagnostic Radiology, Mayo Clinic, Rochester, MN, USA
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23833
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Moyer JR, Power JM, Thompson LT, Disterhoft JF. Increased excitability of aged rabbit CA1 neurons after trace eyeblink conditioning. J Neurosci 2000; 20:5476-82. [PMID: 10884331 PMCID: PMC6772307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Cellular properties of CA1 neurons were studied in hippocampal slices 24 hr after acquisition of trace eyeblink conditioning in young adult and aging rabbits. Aging rabbits required significantly more trials than young rabbits to reach a behavioral criterion of 60% conditioned responses in an 80 trial session. Intracellular recordings revealed that CA1 neurons from aging control rabbits had significantly larger, longer lasting postburst afterhyperpolarizations (AHPs) and greater spike frequency adaptation (accommodation) relative to those from young adult control rabbits. After learning, both young and aging CA1 neurons exhibited increased postsynaptic excitability compared with their respective age-matched control rabbits (naive and rabbits that failed to learn). Thus, after learning, CA1 neurons from both age groups had reduced postburst AHPs and reduced accommodation. No learning-related differences were seen in resting membrane potential, membrane time constant, neuron input resistance, or action potential characteristics. Furthermore, comparisons between CA1 neurons from trace-conditioned aging and trace-conditioned young adult rabbits revealed no statistically significant differences in postburst AHPs or accommodation, indicating that similar levels of postsynaptic excitability were attained during successful acquisition of trace eyeblink conditioning, regardless of rabbit age. These data represent the first in vitro demonstration of learning-related excitability changes in aging rabbit CA1 neurons and provide additional evidence for involvement of changes in postsynaptic excitability of CA1 neurons in both aging and learning.
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Affiliation(s)
- J R Moyer
- Department of Cell and Molecular Biology and the Institute for Neurosciences, Northwestern University Medical School, Chicago, Illinois 60611-3008, USA.
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23834
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Antebi A, Yeh WH, Tait D, Hedgecock EM, Riddle DL. daf-12 encodes a nuclear receptor that regulates the dauer diapause and developmental age in C. elegans. Genes Dev 2000; 14:1512-27. [PMID: 10859169 PMCID: PMC316684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The daf-12 gene acts at the convergence of pathways regulating larval diapause, developmental age, and adult longevity in Caenorhabditis elegans. It encodes a nuclear receptor most closely related to two C. elegans receptors, NHR-8 and NHR-48, Drosophila DHR96, and vertebrate vitamin D and pregnane-X receptors. daf-12 has three predicted protein isoforms, two of which contain DNA- and ligand-binding domains, and one of which contains the ligand-binding domain only. Mutations cluster in DNA- and ligand-binding domains, but correspond to distinct phenotypic classes. DAF-12 is expressed widely in target tissues from embryo to adult, but is upregulated during midlarval stages. In the adult, expression persists in nervous system and somatic gonad, two tissues that regulate adult longevity. We propose that DAF-12 integrates hormonal signals in cellular targets to coordinate major life history traits.
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Affiliation(s)
- A Antebi
- Max-Planck-Institut fuer Molekulare Genetik, Ihnestrasse 73 14195 Berlin, Germany
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23835
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Lowther WT, Brot N, Weissbach H, Honek JF, Matthews BW. Thiol-disulfide exchange is involved in the catalytic mechanism of peptide methionine sulfoxide reductase. Proc Natl Acad Sci U S A 2000; 97:6463-8. [PMID: 10841552 PMCID: PMC18625 DOI: 10.1073/pnas.97.12.6463] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [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: 11/18/2022] Open
Abstract
Peptide methionine sulfoxide reductase (MsrA; EC ) reverses the inactivation of many proteins due to the oxidation of critical methionine residues by reducing methionine sulfoxide, Met(O), to methionine. MsrA activity is independent of bound metal and cofactors but does require reducing equivalents from either DTT or a thioredoxin-regenerating system. In an effort to understand these observations, the four cysteine residues of bovine MsrA were mutated to serine in a series of permutations. An analysis of the enzymatic activity of the variants and their free sulfhydryl states by mass spectrometry revealed that thiol-disulfide exchange occurs during catalysis. In particular, the strictly conserved Cys-72 was found to be essential for activity and could form disulfide bonds, only upon incubation with substrate, with either Cys-218 or Cys-227, located at the C terminus. The significantly decreased activity of the Cys-218 and Cys-227 variants in the presence of thioredoxin suggested that these residues shuttle reducing equivalents from thioredoxin to the active site. A reaction mechanism based on the known reactivities of thiols with sulfoxides and the available data for MsrA was formulated. In this scheme, Cys-72 acts as a nucleophile and attacks the sulfur atom of the sulfoxide moiety, leading to the formation of a covalent, tetracoordinate intermediate. Collapse of the intermediate is facilitated by proton transfer and the concomitant attack of Cys-218 on Cys-72, leading to the formation of a disulfide bond. The active site is returned to the reduced state for another round of catalysis by a series of thiol-disulfide exchange reactions via Cys-227, DTT, or thioredoxin.
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Affiliation(s)
- W T Lowther
- Institute of Molecular Biology, Howard Hughes Medical Institute and Department of Physics, 1229 University of Oregon, Eugene, OR 97403-1229, USA
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23836
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Niblock MM, Brunso-Bechtold JK, Riddle DR. Insulin-like growth factor I stimulates dendritic growth in primary somatosensory cortex. J Neurosci 2000; 20:4165-76. [PMID: 10818152 PMCID: PMC6772633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The temporal and spatial distributions of several growth factors suggest roles in the regulation of neuronal differentiation in the neocortex. Among such growth factors, the insulin-like growth factors (IGF-I and -II) are of particular interest because they are available to neurons from multiple sources under independent control. IGF-I is produced by many neurons throughout the brain and also by cells in the cerebral vasculature. IGF-II is found at high levels in the CSF, and both IGF-I and IGF-II cross the blood-brain barrier. Thus, the IGFs may act as both paracrine and endocrine regulators of neuronal development. As an initial step toward understanding the influence of IGFs in the developing cerebral cortex, the present study examined the effects of IGF-I and of the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) on the dendritic complexity of layer 2 pyramidal neurons. The results demonstrate that IGF-I increased the branching and total extent of both apical and basal dendrites of pyramidal cells in organotypic slices of rat primary somatosensory cortex. BDNF and NT-3 also enhanced dendritic development, but the two neurotrophins increased the extent of only basal, not apical, dendrites and promoted greater elongation than was seen after IGF-I treatment. These results provide direct evidence that IGF-I can regulate the dendritic elaboration of cortical neurons and indicate that endogenous IGFs may influence dendritic differentiation and the formation of cortical connections. In addition, IGF-dependent regulation of dendritic structure may represent a link between age-related declines in IGFs and cognitive deficits seen in senescence.
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Affiliation(s)
- M M Niblock
- Department of Neurobiology and Anatomy and Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1010, USA
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23837
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Remy S, Fulcrand H, Labarbe B, Cheynier V, Moutounet M. First confirmation in red wine of products resulting from direct anthocyanin-tannin reactions. J Sci Food Agric 2000; 80:745-751. [PMID: 29345778 DOI: 10.1002/(sici)1097-0010(20000501)80:6<745::aid-jsfa611>3.0.co;2-4] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/1999] [Revised: 11/26/1999] [Accepted: 01/17/2000] [Indexed: 06/07/2023]
Abstract
Analysis of wine fractions before and after thiolysis confirmed the occurrence in red wine of direct reactions between anthocyanins and tannins established earlier in model solutions. Results showed the presence of two types of structures differing in the linkage position of the anthocyanin moiety. On one hand, detection of malvidin-3-glucoside (Mv3g) among thiolysis products revealed the presence of anthocyanin-derived pigments in which Mv3g is linked by its C-6 or C-8 top. On the other hand, LC/MS analysis allowed the detection of two derivatives tentatively identified as flavenes or a bicyclic condensation products yielded by the reaction of a flavanol monomer (C-6 or C-8 top) with malvidin-3-glucoside (C-4 position). The presence of the corresponding benzylthioethers after thiolysis of the polymeric fractions confirmed that procyanidins are similarly involved in the latter reaction. Besides, MS also allowed the detection of new benzylthioethers of catechin derivatives released after thiolysis of the wine fractions, indicating that in addition to the postulated processes other types of reactions take place in wines. © 2000 Society of Chemical Industry.
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Affiliation(s)
- Sophie Remy
- INRA-Institut des Produits de la Vigne, Unité de Recherches Biopolymères et Arômes, 2 Place Viala, F-34060 Montpellier Cedex 2, France
| | - Hélène Fulcrand
- INRA-Institut des Produits de la Vigne, Unité de Recherches Biopolymères et Arômes, 2 Place Viala, F-34060 Montpellier Cedex 2, France
| | - Benoît Labarbe
- INRA-Institut des Produits de la Vigne, Unité de Recherches Biopolymères et Arômes, 2 Place Viala, F-34060 Montpellier Cedex 2, France
| | - Véronique Cheynier
- INRA-Institut des Produits de la Vigne, Unité de Recherches Biopolymères et Arômes, 2 Place Viala, F-34060 Montpellier Cedex 2, France
| | - Michel Moutounet
- INRA-Institut des Produits de la Vigne, Unité de Recherches Biopolymères et Arômes, 2 Place Viala, F-34060 Montpellier Cedex 2, France
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23838
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Sadraie SH, Saito H, Kaneko T, Saito T, Hiroi M. Effects of aging on ovarian fecundity in terms of the incidence of apoptotic granulosa cells. J Assist Reprod Genet 2000; 17:168-73. [PMID: 10911578 PMCID: PMC3455660 DOI: 10.1023/a:1009422323306] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE The objective was to determine the effects of women's age on the ovarian fecundity as assessed by the incidence of apoptotic granulosa cells. METHODS Twenty-eight normo-ovulatory women underwent ovulation induction for standard IVF. The husbands of these women showed severe male infertility factors. The women were divided into four groups according to their ages. Women underwent follicle aspiration after the administration of human menopausal gonadotropin plus human chorionic gonadotropin. The nuclei of granulosa cells were examined by using fluorescence microscopy, and the incidence of apoptotic granulosa cells was tabulated. RESULTS Granulosa cells in the older women revealed a significant increase in the number of apoptotic cells. The number of total oocytes and the number of mature oocytes obtained significantly decreased with age. However, endometrial thickness and follicular estradiol, progesterone, and free testosterone levels were not significantly different among four different age groups. CONCLUSIONS Age increases apoptotic changes in granulosa cells and consequently decreases the ovarian fecundity.
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Affiliation(s)
- S H Sadraie
- Department of Obstetrics and Gynecology, Yamagata University, School of Medicine, Japan
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23839
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Magnusson KR. Declines in mRNA expression of different subunits may account for differential effects of aging on agonist and antagonist binding to the NMDA receptor. J Neurosci 2000; 20:1666-74. [PMID: 10684868 PMCID: PMC6772913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The purpose of the present study was to determine whether some of the age-related changes that occur in binding to the NMDA receptor complex can be accounted for by changes in subunit expression during the aging process. In situ hybridization for the NMDA subunits zeta1, epsilon1, and epsilon2, and receptor autoradiography, using the agonist glutamate and the competitive antagonist [(+/-)-2-carboxypiperazin-4-yl] propyl-1-phosphonic acid (CPP), were performed on sections from C57Bl/6 mice representing three different age groups (3, 10, and 30 months of age). There was a significant overall decrease between 3 and 30 month olds in the density of mRNA for the zeta1 subunit in the cortex and hippocampus, but only a few individual brain regions exhibited significant declines. The mRNA for the epsilon2 subunit was significantly decreased in a majority of cortical regions and in the dentate granule cells. Emulsion analysis indicated that the change in the density of epsilon2 subunit mRNA in the inner frontal cortex was primarily attributable to a decrease in the amount of messages per cell. Age-related changes in mRNA density of the epsilon2 subunit correlated with changes in NMDA-displaceable [(3)H]glutamate binding, and mRNA density changes in the zeta1 subunit showed a significant relationship with changes in [(3)H]CPP binding in the 30-month-old mice. These results suggest that changes during aging in the expression of different subunits of the NMDA receptor may account for the differential effects of aging on agonist versus antagonist binding to the NMDA binding site.
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Affiliation(s)
- K R Magnusson
- Department of Anatomy, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523-1670, USA.
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23840
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HUANG DONGYA, SHENOY ARUNDATHI, CUI JIANKUN, HUANG WEIYONG, LIU PHILIPK. In situ detection of AP sites and DNA strand breaks bearing 3'-phosphate termini in ischemic mouse brain. FASEB J 2000; 14:407-17. [PMID: 10657997 PMCID: PMC2746459 DOI: 10.1096/fasebj.14.2.407] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [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: 11/11/2022]
Abstract
Our aims were to examine whether oxidative DNA damage was elevated in brain cells of male C57BL/6 mice after oxidative stress, and to determine whether neuronal nitric oxide synthase (nNOS) was involved in such damage. Oxidative stress was induced by occluding both common carotid arteries for 90 min, followed by reperfusion. Escherichia coli exonuclease III (Exo III) removes apyrimidinic or apurinic (AP) sites and 3'-phosphate termini in single-strand breaks, and converts these lesions to 3'OH termini. These ExoIII-sensitive sites (EXOSS) can then be postlabeled using digoxigenin-11-dUTP and Klenow DNA polymerase-I, and detected using fluorescein isothiocyanate-IgG against digoxigenin. Compared with the non-ischemia controls, the density of EXOSS-positive cells was elevated at least 20-fold (P < 0.01) at 15 min of reperfusion, and remained elevated for another 30 min. EXOSS mainly occurred in the cell nuclei of the astrocytes and neurons. Signs of cell death were detected at 24 h of reperfusion and occurred mostly in the neurons. Both DNA damage and cell death in the cerebral cortical neurons were abolished by treatment with 3-bromo-7-nitroindazole (30 mg/kg, intraperitoneal), which specifically inhibited nNOS. Our results suggest that nNOS, its activator (calcium), and peroxynitrite exacerbate oxidative DNA damage after brain ischemia.-Huang, D., Shenoy, A., Cui, J., Huang, W., Liu, P. In situ detection of AP sites and DNA strand breaks bearing 3'-phosphate termini in ischemic mouse brain.
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Affiliation(s)
| | | | | | | | - PHILIP K. LIU
- Correspondence: Department of Neurosurgery, 6560 Fannin St., Suite 944, Baylor College of Medicine, Houston, TX 77030. E-mail:
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23841
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Abstract
Apurinic/apyrimidinic (AP) sites are common DNA lesions that arise from spontaneous depurination or by base excision repair (BER) of modified bases. A biotin-containing aldehyde-reactive probe (ARP) [Kubo, K., Ide, H., Wallace, S. S. & Kow, Y. W. (1992) Biochemistry 31, 3703-3708] is used to measure AP sites in living cells. ARP penetrates the plasma membrane of cells and reacts with AP sites in DNA to form a stable ARP-DNA adduct. The DNA is isolated and treated with avidin-horseradish peroxidase (HRP), forming a DNA-HRP complex at each biotin residue, which is rapidly separated from free avidin-HRP by selective precipitation with a DNA precipitating dye (DAPER). The number of AP sites is estimated by HRP activity toward chromogenic substrate in an ELISA assay. The assay integrates the AP sites formed by the different glycosylases of BER during a 1-h incubation and eliminates artifactual depurination or loss of AP sites during DNA isolation. The assay was applied to living cells and nuclei. The number of AP sites after a 1-h incubation in old IMR90 cells was about two to three times higher than that in young cells, and the number in human leukocytes from old donors was about seven times that in young donors. The repair of AP sites was slower in senescent compared with young IMR90 cells. An age-dependent decline is shown in the activity of the glycosylase that removes methylated bases in IMR90 cells and in human leukocytes. The decline in excision of methylated bases from DNA suggests an age-dependent decline in 3-methyladenine DNA glycosylase, a BER enzyme responsible for removing alkylated bases.
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Affiliation(s)
- H Atamna
- Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA
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23842
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Bellis TJ, Nicol T, Kraus N. Aging affects hemispheric asymmetry in the neural representation of speech sounds. J Neurosci 2000; 20:791-7. [PMID: 10632608 PMCID: PMC6772399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Hemispheric asymmetries in the processing of elemental speech sounds appear to be critical for normal speech perception. This study investigated the effects of age on hemispheric asymmetry observed in the neurophysiological responses to speech stimuli in three groups of normal hearing, right-handed subjects: children (ages, 8-11 years), young adults (ages, 20-25 years), and older adults (ages > 55 years). Peak-to-peak response amplitudes of the auditory cortical P1-N1 complex obtained over right and left temporal lobes were examined to determine the degree of left/right asymmetry in the neurophysiological responses elicited by synthetic speech syllables in each of the three subject groups. In addition, mismatch negativity (MMN) responses, which are elicited by acoustic change, were obtained. Whereas children and young adults demonstrated larger P1-N1-evoked response amplitudes over the left temporal lobe than over the right, responses from elderly subjects were symmetrical. In contrast, MMN responses, which reflect an echoic memory process, were symmetrical in all subject groups. The differences observed in the neurophysiological responses were accompanied by a finding of significantly poorer ability to discriminate speech syllables involving rapid spectrotemporal changes in the older adult group. This study demonstrates a biological, age-related change in the neural representation of basic speech sounds and suggests one possible underlying mechanism for the speech perception difficulties exhibited by aging adults. Furthermore, results of this study support previous findings suggesting a dissociation between neural mechanisms underlying those processes that reflect the basic representation of sound structure and those that represent auditory echoic memory and stimulus change.
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Affiliation(s)
- T J Bellis
- Auditory Neuroscience Laboratory, Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois.
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23843
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Sheng JG, Mrak RE, Bales KR, Cordell B, Paul SM, Jones RA, Woodward S, Zhou XQ, McGinness JM, Griffin WST. Overexpression of the neuritotrophic cytokine S100beta precedes the appearance of neuritic beta-amyloid plaques in APPV717F mice. J Neurochem 2000; 74:295-301. [PMID: 10617132 PMCID: PMC3903403 DOI: 10.1046/j.1471-4159.2000.0740295.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [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: 11/20/2022]
Abstract
Homozygous APPV717F transgenic mice overexpress a human beta-amyloid precursor protein (betaAPP) minigene encoding a familial Alzheimer's disease mutation. These mice develop Alzheimer-type neuritic beta-amyloid plaques surrounded by astrocytes. S100beta is an astrocyte-derived cytokine that promotes neurite growth and promotes excessive expression of betaAPP. S100beta overexpression in Alzheimer's disease correlates with the proliferation of betaAPP-immunoreactive neurites in beta-amyloid plaques. We found age-related increases in tissue levels of both betaAPP and S100beta mRNA in transgenic mice. Neuronal betaAPP overexpression was found in cell somas in young mice, whereas older mice showed betaAPP overexpression in dystrophic neurites in plaques. These age-related changes were accompanied by progressive increases in S100beta expression, as determined by S100beta load (percent immunoreactive area). These increases were evident as early as 1 and 2 months of age, months before the appearance of beta-amyloid deposits in these mice. Such precocious astrocyte activation and S100beta overexpression are similar to our earlier findings in Down's syndrome. Accelerated age-related overexpression of S100beta may interact with age-associated overexpression of mutant betaAPP in transgenic mice to promote development of Alzheimer-like neuropathological changes.
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Affiliation(s)
- J. G. Sheng
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
- Department of Neurology, Rui-Jin Hospital, Shanghai Second Medical University, Shanghai, China
| | - R. E. Mrak
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
- Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
- Pathology Service, Department of Veterans’ Affairs Medical Center, Little Rock, Arkansas, U.S.A
| | | | | | | | - R. A. Jones
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
- Geriatric, Education and Clinical Centers, Little Rock, Arkansas, U.S.A
| | - S. Woodward
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - X. Q. Zhou
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - J. M. McGinness
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
| | - W. S. T. Griffin
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
- Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A
- Geriatric, Education and Clinical Centers, Little Rock, Arkansas, U.S.A
- Mental Illness Research, Education and Clinical Centers, Little Rock, Arkansas, U.S.A
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23844
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Park JE, Lee WH, Hwang TH, Chu JA, Kim S, Choi YH, Kim JS, Kim DK, Lee SH, Hong KP, Seo JD, Lee WR. Aging affects the association between endothelial nitric oxide synthase gene polymorphism and acute myocardial infarction in the Korean male population. Korean J Intern Med 2000; 15:65-70. [PMID: 10714094 PMCID: PMC4531736 DOI: 10.3904/kjim.2000.15.1.65] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVES The aging process affects responsiveness and other functions of endothelium and vascular smooth muscle cells, predisposing the old vessels to the development of atherosclerotic lesions. Endothelial nitric oxide synthase (ecNOS) gene polymorphisms were shown to affect the occurrence of acute myocardial infarction (AMI). We hypothesized that aging may affect the association between the ecNOS gene polymorphism and AMI. METHODS We investigated the age-related distribution of the ecNOS gene a/b polymorphism in 121 male AMI patients and 206 age-matched healthy male controls. RESULTS The aa, ab and bb genotypes were found in 1, 49 and 156 cases among the control subjects and 5, 23 and 93 cases among the AMI patients, respectively. There was a significant correlation between the ecNOS polymorphism and AMI (p = 0.045). When the correlation was analyzed by age, the significance remained only in the group below the age of 51 (p = 0.009). The proportion of smokers was increased in the young patients when compared to the old patients (p = 0.033), indicating that smoking also has greater effect on the younger population. The incidences of hypertension and diabetes mellitus, however, were similar in both populations. CONCLUSION Our work provides the first evidence that links ecNOS polymorphism to the risk of AMI in relation to age. Young persons who smoke or have ecNOSaa genotype may have an increased risk of developing AMI. The functional as well as structural changes associated with aging in the vascular endothelium may mask the effect of the ecNOS polymorphism in the development of AMI in old persons.
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Affiliation(s)
- J E Park
- Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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23845
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Lauterborn JC, Lynch G, Vanderklish P, Arai A, Gall CM. Positive modulation of AMPA receptors increases neurotrophin expression by hippocampal and cortical neurons. J Neurosci 2000; 20:8-21. [PMID: 10627576 PMCID: PMC6774091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/1999] [Revised: 10/04/1999] [Accepted: 10/08/1999] [Indexed: 02/15/2023] Open
Abstract
This study investigated whether positive modulators of AMPA-type glutamate receptors influence neurotrophin expression by forebrain neurons. Treatments with the ampakine CX614 markedly and reversibly increased brain-derived neurotrophic factor (BDNF) mRNA and protein levels in cultured rat entorhinal/hippocampal slices. Acute effects of CX614 were dose dependent over the range in which the drug increased synchronous neuronal discharges; threshold concentrations for acute responses had large effects on mRNA content when applied for 3 d. Comparable results were obtained with a second, structurally distinct ampakine CX546. Ampakine-induced upregulation was broadly suppressed by AMPA, but not NMDA, receptor antagonists and by reducing transmitter release. Antagonism of L-type voltage-sensitive calcium channels blocked induction in entorhinal cortex but not hippocampus. Prolonged infusions of suprathreshold ampakine concentrations produced peak BDNF mRNA levels at 12 hr and a return to baseline levels by 48 hr. In contrast, BDNF protein remained elevated throughout a 48 hr incubation with the drug. Nerve growth factor mRNA levels also were increased by ampakines but with a much more rapid return to control levels during chronic administration. Finally, intraperitoneal injections of CX546 increased hippocampal BDNF mRNA levels in aged rats and middle-aged mice. The present results provide evidence of regional differences in mechanisms via which activity regulates neurotrophin expression. Moreover, these data establish that changes in synaptic potency produce sufficient network level physiological effects for inducing neurotrophin genes, indicate that the response becomes refractory during prolonged ampakine exposure, and raise the possibility of using positive AMPA modulators to regulate neurotrophin levels in aged brain.
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Affiliation(s)
- J C Lauterborn
- Department of Anatomy and Neurobiology, University of California, Irvine, California 92697-4292, USA.
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23846
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Abstract
SUMMARY The author traces her changes in attitude toward her body, sexuality, and public disclosure of her lesbianism through reflections upon her writings as the years pass. She addresses the connections between the body and writing, and celebrates the community of lesbian writers who push outward the boundaries of language to assert that there are no boundaries.
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23847
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Nicolle MM, Colombo PJ, Gallagher M, McKinney M. Metabotropic glutamate receptor-mediated hippocampal phosphoinositide turnover is blunted in spatial learning-impaired aged rats. J Neurosci 1999; 19:9604-10. [PMID: 10531462 PMCID: PMC6782926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Maximal phosphoinositide (PI) turnover was examined in the hippocampus of young and aged Long-Evans rats that were behaviorally characterized for spatial learning in the Morris water maze. The type 1 metabotropic glutamate receptor (mGluR) agonist 1S,3R ACPD was used to stimulate PI turnover and to determine the E(MAX) for each rat. Protein levels in hippocampus for type 1 mGluRs, Galphaq11, and phospholipase Cbeta-1 (PLCbeta-1) were also measured by quantitative Western blotting. The results show that PI turnover mediated by the mGluRs was blunted in the aged rats. The magnitude of the decrement in PI turnover was also significantly correlated with age-related spatial memory decline. The decrease in mGluR-mediated PI turnover occurred without changes in the protein level of either the mGluRs or the G-protein coupled to those receptors, Galphaq11. A significant decrease in the immunoreactivity of PLCbeta-1, however, was observed in the hippocampus of aged rats; PLCbeta-1 immunoreactivity was significantly correlated with spatial learning only when the young and aged rats were considered together. The decrement in mGluR-mediated signal transduction in the hippocampus that is related to cognitive impairment in aging may be attributable, at least in part, to a deficiency in the enzyme PLCbeta-1. That deficiency may also contribute to a blunted response in muscarinic stimulation of hippocampal PI turnover that we previously found in this same study population. An age-related alteration in this signal transduction system may provide a functional basis for cognitive decline independent of any loss of neurons in the hippocampus.
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Affiliation(s)
- M M Nicolle
- Mayo Clinic, Department of Pharmacology, Jacksonville, Florida 32224, USA.
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23848
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Haynes L, Linton PJ, Eaton SM, Tonkonogy SL, Swain SL. Interleukin 2, but not other common gamma chain-binding cytokines, can reverse the defect in generation of CD4 effector T cells from naive T cells of aged mice. J Exp Med 1999; 190:1013-24. [PMID: 10510091 PMCID: PMC2195647 DOI: 10.1084/jem.190.7.1013] [Citation(s) in RCA: 196] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/1999] [Accepted: 07/27/1999] [Indexed: 12/02/2022] Open
Abstract
Development of effectors from naive CD4 cells occurs in two stages. The early stage involves activation and limited proliferation in response to T cell receptor (TCR) stimulation by antigen and costimulatory antigen presenting cells, whereas the later stage involves proliferation and differentiation in response to growth factors. Using a TCR-transgenic (Tg(+)) model, we have examined the effect of aging on effector generation and studied the ability of gamma(c) signaling cytokines to reverse this effect. Our results indicate that responding naive CD4 cells from aged mice, compared with cells from young mice, make less interleukin (IL)-2, expand poorly between days 3 to 5, and give rise to fewer effectors with a less activated phenotype and reduced ability to produce cytokines. When exogenous IL-2 or other gamma(c) signaling cytokines are added during effector generation, the Tg(+) cells from both young and aged mice proliferate vigorously. However, IL-4, IL-7, and IL-15 all fail to restore efficient effector production. Only effectors from aged mice generated in the presence of IL-2 are able to produce IL-2 in amounts equivalent to those produced by effectors generated from young mice, suggesting that the effect of aging on IL-2 production is reversible only in the presence of exogenous IL-2.
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MESH Headings
- Aging/immunology
- Animals
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- Cell Differentiation/drug effects
- Cell Differentiation/immunology
- Cells, Cultured
- Cytokines/biosynthesis
- Cytokines/pharmacology
- H-2 Antigens/immunology
- Interferon-gamma/biosynthesis
- Interferon-gamma/pharmacology
- Interleukin-2/biosynthesis
- Interleukin-2/pharmacology
- Interleukin-4/biosynthesis
- Interleukin-4/pharmacology
- Interleukin-5/biosynthesis
- Interleukin-5/pharmacology
- Lymphocyte Activation
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Mice, Transgenic
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Recombinant Proteins/pharmacology
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- Th1 Cells/immunology
- Th2 Cells/immunology
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Affiliation(s)
- L Haynes
- Trudeau Institute, Saranac Lake, New York 12983, USA.
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23849
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Abstract
The SIR genes are determinants of life span in yeast mother cells. Here we show that life span regulation by the Sir proteins is independent of their role in nonhomologous end joining. The short life span of a sir3 or sir4 mutant is due to the simultaneous expression of a and alpha mating-type information, which indirectly causes an increase in rDNA recombination and likely increases the production of extrachromosomal rDNA circles. The short life span of a sir2 mutant also reveals a direct failure to repress recombination generated by the Fob1p-mediated replication block in the rDNA. Sir2p is a limiting component in promoting yeast longevity, and increasing the gene dosage extends the life span in wild-type cells. A possible role of the conserved SIR2 in mammalian aging is discussed.
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Affiliation(s)
- M Kaeberlein
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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23850
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Phinney AL, Deller T, Stalder M, Calhoun ME, Frotscher M, Sommer B, Staufenbiel M, Jucker M. Cerebral amyloid induces aberrant axonal sprouting and ectopic terminal formation in amyloid precursor protein transgenic mice. J Neurosci 1999; 19:8552-9. [PMID: 10493755 PMCID: PMC6783025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
A characteristic feature of Alzheimer's disease (AD) is the formation of amyloid plaques in the brain. Although this hallmark pathology has been well described, the biological effects of plaques are poorly understood. To study the effect of amyloid plaques on axons and neuronal connectivity, we have examined the axonal projections from the entorhinal cortex in aged amyloid precursor protein (APP) transgenic mice that exhibit cerebral amyloid deposition in plaques and vessels (APP23 mice). Here we report that entorhinal axons form dystrophic boutons around amyloid plaques in the entorhinal termination zone of the hippocampus. More importantly, entorhinal boutons were found associated with amyloid in ectopic locations within the hippocampus, the thalamus, white matter tracts, as well as surrounding vascular amyloid. Many of these ectopic entorhinal boutons were immunopositive for the growth-associated protein GAP-43 and showed light and electron microscopic characteristics of axonal terminals. Our findings suggest that (1) cerebral amyloid deposition has neurotropic effects and is the main cause of aberrant sprouting in AD brain; (2) the magnitude and significance of sprouting in AD have been underestimated; and (3) cerebral amyloid leads to the disruption of neuronal connectivity which, in turn, may significantly contribute to AD dementia.
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Affiliation(s)
- A L Phinney
- Department of Neuropathology, Institute of Pathology, University of Basel, CH-4003 Basel, Switzerland
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