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Llibre-Guerra JJ, Heavener A, Brucki SMD, Marante JPD, Pintado-Caipa M, Chen Y, Behrens MI, Hardi A, Admirall-Sanchez A, Akinyemi R, Alladi S, Dorsman KA, Rodriguez-Salgado AM, Solorzano J, Babulal GM. A call for clinical trial globalization in Alzheimer's disease and related dementia. Alzheimers Dement 2023; 19:3210-3221. [PMID: 36840622 PMCID: PMC10450094 DOI: 10.1002/alz.12995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 02/26/2023]
Abstract
BACKGROUND The burden of Alzheimer's disease and related dementia (ADRD) is projected to disproportionally impact low-middle-income countries (LMICs). However, there is a systematic under-representation of LMICs in ADRD clinical trial platforms. METHODS We aimed to determine the global distribution of ADRD clinical trials and identify existing barriers for conducting clinical trials in LMICs. Primary data sources to identify trial distribution in LMICs included ClinicalTrials.gov and the International Trials Registry Platform. An additional systematic review and expert consensus interviews were conducted to identify barriers for conducting clinical trials in LMICs. FINDINGS Among 1237 disease-modifying therapies tested in ADRD clinical trials, only 11.6% have been or are conducted in emerging economies (upper-middle income [9.6%] and low-middle income [2.0%]). We identified several limitations for trial implementation including a lack of financial resources, low industry presence, regulatory obstacles, and operational barriers INTERPRETATION: Although LMICs bear the greatest burden of ADRD globally, substantial development of clinical trial platforms to address this inequity and health disparity is lacking.
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Affiliation(s)
- Jorge J Llibre-Guerra
- Department of Neurology, Washington University, School of Medicine, St. Louis, Missouri, USA
- Dominantly Inherited Alzheimer's Network Trial Unit, St. Louis, Missouri, USA
- Institute of Public Health, Washington University, St. Louis, Missouri, USA
| | - Anika Heavener
- Department of Global Health and Social Medicine, Harvard Medical School, St. Louis, Missouri, USA
| | - Sonia Maria Dozzi Brucki
- Cognitive and Behavioral Neurology Unit, Department of Neurology, University of Sao Paulo, São Paulo, Brazil
| | | | | | - Yaohua Chen
- Department of Geriatrics, Lille Neurosciences & Cognition, University of Lille, Lille, France
| | - María Isabel Behrens
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Independencia, Santiago, Chile
| | - Angela Hardi
- Becker Medical Library, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | - Rufus Akinyemi
- Centre for Genomic and Precision Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Suvarna Alladi
- National Institute of Mental Health and Neuroscience, Bangalore, India
| | - Karen A Dorsman
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Joel Solorzano
- Department of Medicine, Hospital Antonio Luaces Iralola, Ciego de Avila, Cuba
| | - Ganesh M Babulal
- Department of Neurology, Washington University, School of Medicine, St. Louis, Missouri, USA
- Institute of Public Health, Washington University, St. Louis, Missouri, USA
- Department of Clinical Research and Leadership, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
- Department of Psychology, University of Johannesburg, Johannesburg, South Africa
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Plaza-Rosales I, Brunetti E, Montefusco-Siegmund R, Madariaga S, Hafelin R, Ponce DP, Behrens MI, Maldonado PE, Paula-Lima A. Visual-spatial processing impairment in the occipital-frontal connectivity network at early stages of Alzheimer's disease. Front Aging Neurosci 2023; 15:1097577. [PMID: 36845655 PMCID: PMC9947357 DOI: 10.3389/fnagi.2023.1097577] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/20/2023] [Indexed: 02/11/2023] Open
Abstract
Introduction Alzheimer's disease (AD) is the leading cause of dementia worldwide, but its pathophysiological phenomena are not fully elucidated. Many neurophysiological markers have been suggested to identify early cognitive impairments of AD. However, the diagnosis of this disease remains a challenge for specialists. In the present cross-sectional study, our objective was to evaluate the manifestations and mechanisms underlying visual-spatial deficits at the early stages of AD. Methods We combined behavioral, electroencephalography (EEG), and eye movement recordings during the performance of a spatial navigation task (a virtual version of the Morris Water Maze adapted to humans). Participants (69-88 years old) with amnesic mild cognitive impairment-Clinical Dementia Rating scale (aMCI-CDR 0.5) were selected as probable early AD (eAD) by a neurologist specialized in dementia. All patients included in this study were evaluated at the CDR 0.5 stage but progressed to probable AD during clinical follow-up. An equal number of matching healthy controls (HCs) were evaluated while performing the navigation task. Data were collected at the Department of Neurology of the Clinical Hospital of the Universidad de Chile and the Department of Neuroscience of the Faculty of Universidad de Chile. Results Participants with aMCI preceding AD (eAD) showed impaired spatial learning and their visual exploration differed from the control group. eAD group did not clearly prefer regions of interest that could guide solving the task, while controls did. The eAD group showed decreased visual occipital evoked potentials associated with eye fixations, recorded at occipital electrodes. They also showed an alteration of the spatial spread of activity to parietal and frontal regions at the end of the task. The control group presented marked occipital activity in the beta band (15-20 Hz) at early visual processing time. The eAD group showed a reduction in beta band functional connectivity in the prefrontal cortices reflecting poor planning of navigation strategies. Discussion We found that EEG signals combined with visual-spatial navigation analysis, yielded early and specific features that may underlie the basis for understanding the loss of functional connectivity in AD. Still, our results are clinically promising for early diagnosis required to improve quality of life and decrease healthcare costs.
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Affiliation(s)
- Iván Plaza-Rosales
- Department of Medical Technology, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Enzo Brunetti
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Institute of Neurosurgery and Brain Research Dr. Alfonso Asenjo, Santiago, Chile,Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Rodrigo Montefusco-Siegmund
- Faculty of Medicine, Institute of Locomotor System and Rehabilitation, Universidad Austral de Chile, Valdivia, Chile
| | - Samuel Madariaga
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Rodrigo Hafelin
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Daniela P. Ponce
- Department of Neurology and Neurosurgery, Hospital Clínico Universidad de Chile, Santiago, Chile,Faculty of Medicine, Center for Advanced Clinical Research, Universidad de Chile, Santiago, Chile
| | - María Isabel Behrens
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Department of Neurology and Neurosurgery, Hospital Clínico Universidad de Chile, Santiago, Chile,Faculty of Medicine, Center for Advanced Clinical Research, Universidad de Chile, Santiago, Chile,Department of Neurology and Psychiatry, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - Pedro E. Maldonado
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Pedro E. Maldonado,
| | - Andrea Paula-Lima
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile,Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile,*Correspondence: Andrea Paula-Lima,
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3
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Llibre‐Guerra JJ, Rodriguez‐Salgado AM, Hardi A, Heavener A, Behrens MI, Brucki SMD, Babulal GM, Nitrini R. Alzheimer disease clinical trials in low and middle income countries: A call for globalization of clinical trials. Alzheimers Dement 2022. [DOI: 10.1002/alz.064112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | | | - Angela Hardi
- Washington University School of Medicine St Louis MO USA
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4
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Castillo-Passi RI, Vergara RC, Rogers NK, Ponce D, Bennett M, Behrens MI. Cancer History Is Associated with Slower Speed of Cognitive Decline in Patients with Amnestic Cognitive Impairment. J Alzheimers Dis 2022; 87:1695-1711. [DOI: 10.3233/jad-215660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: Several epidemiological studies report a negative association between Cancer and Alzheimer’s disease (AD). Objective: To characterize the trajectories of memory loss in individuals with early amnestic cognitive impairment with and without history of previous cancer. Methods: Cognitive deterioration was assessed using the Montreal Cognitive Assessment (MoCA) or MoCA-Memory Index Score (MoCA-MIS) biannually in subjects with early amnestic cognitive impairment followed-up retrospectively from 2007 to 2021. History of Cancer was obtained from clinical records. Simple linear regressions of MoCA-MIS scores were calculated for each subject and analyzed with K-means cluster analysis to identify subgroups with different cognitive decline trajectories. χ 2 and t tests were used for descriptive categorical and continuous variables and mixed multiple linear regressions to determine cognitive decline covariates. Results: Analysis of the trajectory of cognitive decline in 141 subjects with early amnestic cognitive impairment identified two subgroups: Fast (n = 60) and Slow (n = 81) progressors. At baseline Fast progressors had better MoCA-MIS (p < 0.001) and functionality (CDR p = 0.02, AD8 p = 0.05), took less anti-dementia medications (p = 0.005), and had higher depression rates (p = 0.02). Interestingly, Fast progressors slowed their speed of memory decline (from 1.6 to 1.1 MoCA-MIS points/year) and global cognitive decline (from 2.0 to 1.4 total MoCA points/year) when Cancer history was present. Conclusion: Two trajectories of amnestic cognitive decline were identified, possibly derived from different neurophysiopathologies or clinical stages. This study suggests that a history of previous Cancer slows down amnestic cognitive decline, specifically in a subgroup of subjects with depression at baseline and accelerated deterioration at follow-up.
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Affiliation(s)
- Rolando I. Castillo-Passi
- Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico de la Universidad de Chile, Independencia, Santiago, RM, Chile
- Departamento de Neurología y Psiquiatría, CAS, Clínica Alemana Universidad del Desarrollo, Santiago, RM, Chile
- Millennium Nucleus to Improve the Mental Health of Adolescents and Youths, Imhay, Chile
| | - Rodrigo C. Vergara
- Departamento de Kinesiología, Facultad de Artes y Educación Física, Universidad Metropolitana de Ciencias de la Educación, Santiago, RM, Chile
| | - Nicole K. Rogers
- Departamento de Neurociencia, Facultad de Medicina Universidad de Chile, Independencia Santiago, RM, Chile
- Instituto de Neurocirugía Dr. Alfonso Asenjo, Providencia, Santiago, RM, Chile
| | - Daniela Ponce
- Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico de la Universidad de Chile, Independencia, Santiago, RM, Chile
| | - Magdalena Bennett
- IROM Department, McCombs School of Business, The University of Texas at Austin, Austin, TX, USA
| | - María Isabel Behrens
- Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico de la Universidad de Chile, Independencia, Santiago, RM, Chile
- Departamento de Neurología y Neurocirugía, Hospital Clínico, Universidad de Chile, Independencia, Santiago, RM, Chile
- Departamento de Neurociencia, Facultad de Medicina Universidad de Chile, Independencia Santiago, RM, Chile
- Departamento de Neurología y Psiquiatría, CAS, Clínica Alemana Universidad del Desarrollo, Santiago, RM, Chile
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5
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Leyton E, Matus D, Espinoza S, Benitez JM, Cortés BI, Gomez W, Arévalo NB, Murgas P, Manque P, Woehlbier U, Duran-Aniotz C, Hetz C, Behrens MI, SanMartín CD, Nassif M. DEF8 and Autophagy-Associated Genes Are Altered in Mild Cognitive Impairment, Probable Alzheimer’s Disease Patients, and a Transgenic Model of the Disease. J Alzheimers Dis 2021; 82:S163-S178. [DOI: 10.3233/jad-201264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Background: Disturbances in the autophagy/endolysosomal systems are proposed as early signatures of Alzheimer’s disease (AD). However, few studies are available concerning autophagy gene expression in AD patients. Objective: To explore the differential expression of classical genes involved in the autophagy pathway, among them a less characterized one, DEF8 (Differentially expressed in FDCP 8), initially considered a Rubicon family member, in peripheral blood mononuclear cells (PBMCs) from individuals with mild cognitive impairment (MCI) and probable AD (pAD) and correlate the results with the expression of DEF8 in the brain of 5xFAD mice. Method: By real-time PCR and flow cytometry, we evaluated autophagy genes levels in PBMCs from MCI and pAD patients. We evaluated DEF8 levels and its localization in brain samples of the 5xFAD mice by real-time PCR, western blot, and immunofluorescence. Results: Transcriptional levels of DEF8 were significantly reduced in PBMCs of MCI and pAD patients compared with healthy donors, correlating with the MoCA and MoCA-MIS cognitive tests scores. DEF8 protein levels were increased in lymphocytes from MCI but not pAD, compared to controls. In the case of brain samples from 5xFAD mice, we observed a reduced mRNA expression and augmented protein levels in 5xFAD compared to age-matched wild-type mice. DEF8 presented a neuronal localization. Conclusion: DEF8, a protein proposed to act at the final step of the autophagy/endolysosomal pathway, is differentially expressed in PBMCs of MCI and pAD and neurons of 5xFAD mice. These results suggest a potential role for DEF8 in the pathophysiology of AD.
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Affiliation(s)
- Esteban Leyton
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Escuela de Tecnología Médica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Diego Matus
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Escuela de Tecnología Médica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Sandra Espinoza
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
| | - José Matías Benitez
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Bastián I. Cortés
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
| | - Wileidy Gomez
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
| | - Nohela B. Arévalo
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
| | - Paola Murgas
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Immunology Laboratory, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
| | - Patricio Manque
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Santiago, Chile
| | - Ute Woehlbier
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Claudia Duran-Aniotz
- Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibañez, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
- Buck Institute for Research on Aging, Novato, CA, USA
| | - María Isabel Behrens
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
- Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico Universidad de Chile, Santiago, Chile
- Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago
| | - Carol D. SanMartín
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Escuela de Tecnología Médica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Melissa Nassif
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
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6
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Arévalo NB, Castillo-Godoy DP, Espinoza-Fuenzalida I, Rogers NK, Farias G, Delgado C, Henriquez M, Herrera L, Behrens MI, SanMartín CD. Association of Vitamin D Receptor Polymorphisms with Amyloid-β Transporters Expression and Risk of Mild Cognitive Impairment in a Chilean Cohort. J Alzheimers Dis 2021; 82:S283-S297. [DOI: 10.3233/jad-201031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background: Amyloid-β peptide (Aβ) deposition in Alzheimer’s disease (AD) is due to an imbalance in its production/clearance rate. Aβ is transported across the blood-brain barrier by LRP1 and P-gp as efflux transporters and RAGE as influx transporter. Vitamin D deficit and polymorphisms of the vitamin D receptor (VDR) gene are associated with high prevalence of mild cognitive impairment (MCI) and AD. Further, vitamin D promotes the expression of LRP1 and P-gp in AD-animal model brains. Objective: To associate VDR polymorphisms Apa I (rs7975232), Taq I (rs731236), and Fok I (rs2228570) with the risk of developing MCI in a Chilean population, and to evaluate the relationship of these polymorphisms to the expression of VDR and Aβ-transporters in peripheral blood mononuclear cells (PBMCs). Methods: VDR polymorphisms Apa I, Taq I, and Fok I were determined in 128 healthy controls (HC) and 66 MCI patients. mRNA levels of VDR and Aβ-transporters were evaluated in subgroups by qPCR. Results: Alleles A of Apa I and C of Taq I were associated with a lower risk of MCI. HC with the Apa I AA genotype had higher mRNA levels of P-gp and LRP1, while the expression of VDR and RAGE were higher in MCI patients and HC. For Fok I, the TC genotype was associated with lower expression levels of Aβ-transporters in both groups. Conclusion: We propose that the response to vitamin D treatment will depend on VDR polymorphisms, being more efficient in carriers of protective alleles of Apa I polymorphism.
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Affiliation(s)
- Nohela B. Arévalo
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Programa de Genética Humana, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | | | | | - Nicole K. Rogers
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gonzalo Farias
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
- Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Carolina Delgado
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Mauricio Henriquez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Red para el Estudio de Enfermedades Cardiopulmonares de Alta Letalidad (REECPAL), Universidad de Chile, Santiago, Chile
| | - Luisa Herrera
- Programa de Genética Humana, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - María Isabel Behrens
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
- Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico Universidad de Chile, Santiago, Chile
- Departamento de Neurología y Psiquiatría, Clínica Alemana de Santiago, Santiago, Chile
| | - Carol D. SanMartín
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile
- Escuela de Tecnologia Médica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
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Arevalo N, Castillo D, Rogers N, Delgado C, Farías G, Behrens MI, SanMartín CD. Apa I, Taq I and Fok I VDR polymorphisms: Functional effect on mRNA levels of amyloid beta transporters
LRP1
and
P‐gp
in lymphocytes of mild cognitive impairment patients. Alzheimers Dement 2020. [DOI: 10.1002/alz.045564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Nicole Rogers
- Atlantic Fellow for Equity in Brain Health at UCSF San Francisco CA USA
- Universidad de Chile Santiago Chile
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8
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Rogers N, Lazcano J, Herrera S, More J, SanMartín CD, Bennett M, Romero C, Grinspun N, Valdés JL, Behrens MI. Physical activity patterns in healthy and cognitively impaired older Chileans using wireless‐enabled wearable technology devices. Alzheimers Dement 2020. [DOI: 10.1002/alz.046303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Nicole Rogers
- Universidad de Chile Santiago Chile
- Atlantic Fellow for Equity in Brain Health at UCSF San Francisco CA USA
| | | | | | | | | | | | | | - Noemí Grinspun
- Universidad Metropolitana de Ciencias de la Educación Santiago Chile
| | | | - María Isabel Behrens
- Universidad de Chile Santiago Chile
- Hospital Clínico de la Universidad de Chile Santiago de Chile Chile
- Clínica Alemana Santiago Chile
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Guerra JJL, Mendez PAC, Allegri RF, Surace E, Llibre‐Rodriguez J, Ibarrola ML, Cornejo‐Olivas M, Sosa‐Ortíz AL, Takada LT, Lopera F, Sanchez V, Jiménez‐Velazquez IZ, Acosta D, Behrens MI, Doering M, Li Y, Morris JC, McDade E, Bateman RJ. Dominantly inherited Alzheimer disease: Frequency, genetic heterogeneity, and clinical phenotype in Latin America. Alzheimers Dement 2020. [DOI: 10.1002/alz.044794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Francisco Lopera
- Grupo de Neurociencias de Antioquia of Universidad de Antioquia Medellin Colombia
| | | | | | - Daisy Acosta
- Universidad Nacional Pedro Henriquez Ureña Santo Domingo Dominican Republic
| | | | - Michelle Doering
- Washington University School of Medicine, St. Louis St Louis MO USA
| | - Yan Li
- Washington University School of Medicine St. Louis MO USA
| | - John C. Morris
- Washington University School of Medicine St. Louis MO USA
| | - Eric McDade
- Knight Alzheimer Disease Research Center St. Louis MO USA
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10
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Llibre-Guerra JJ, Li Y, Allegri RF, Mendez PC, Surace EI, Llibre-Rodriguez JJ, Sosa AL, Aláez-Verson C, Longoria EM, Tellez A, Carrillo-Sánchez K, Flores-Lagunes LL, Sánchez V, Takada LT, Nitrini R, Ferreira-Frota NA, Benevides-Lima J, Lopera F, Ramírez L, Jiménez-Velázquez I, Schenk C, Acosta D, Behrens MI, Doering M, Ziegemeier E, Morris JC, McDade E, Bateman RJ. Dominantly inherited Alzheimer's disease in Latin America: Genetic heterogeneity and clinical phenotypes. Alzheimers Dement 2020; 17:653-664. [PMID: 33226734 DOI: 10.1002/alz.12227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/08/2020] [Accepted: 10/09/2020] [Indexed: 01/21/2023]
Abstract
INTRODUCTION A growing number of dominantly inherited Alzheimer's disease (DIAD) cases have become known in Latin American (LatAm) in recent years. However, questions regarding mutation distribution and frequency by country remain open. METHODS A literature review was completed aimed to provide estimates for DIAD pathogenic variants in the LatAm population. The search strategies were established using a combination of standardized terms for DIAD and LatAm. RESULTS Twenty-four DIAD pathogenic variants have been reported in LatAm countries. Our combined dataset included 3583 individuals at risk; countries with highest DIAD frequencies were Colombia (n = 1905), Puerto Rico (n = 672), and Mexico (n = 463), usually attributable to founder effects. We found relatively few reports with extensive documentation on biomarker profiles and disease progression. DISCUSSION Future DIAD studies will be required in LatAm, albeit with a more systematic approach to include fluid biomarker and imaging studies. Regional efforts are under way to extend the DIAD observational studies and clinical trials to Latin America.
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Affiliation(s)
- Jorge J Llibre-Guerra
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Yan Li
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Ricardo F Allegri
- Department of Cognitive Neurology, Institute for Neurological Research Fleni, Buenos Aires, Argentina
| | - Patricio Chrem Mendez
- Department of Cognitive Neurology, Institute for Neurological Research Fleni, Buenos Aires, Argentina
| | - Ezequiel I Surace
- Department of Cognitive Neurology, Institute for Neurological Research Fleni, Buenos Aires, Argentina
| | | | - Ana Luisa Sosa
- Instituto Nacional de Neurología y Neurocirugía, Ciudad de Mexico, Mexico City, Mexico
| | - Carmen Aláez-Verson
- Laboratorio de Diagnóstico Genómico, Instituto Nacional de Medicina Genómica, Ciudad de México, México
| | | | - Alberto Tellez
- Instituto Nacional de Neurología y Neurocirugía, Ciudad de Mexico, Mexico City, Mexico
| | - Karol Carrillo-Sánchez
- Laboratorio de Diagnóstico Genómico, Instituto Nacional de Medicina Genómica, Ciudad de México, México
| | | | - Victor Sánchez
- Department of Neurology, Hospital das Clinicas, University of São Paulo Medical School, São Paulo, Brazil
| | | | | | | | | | - Francisco Lopera
- University of Puerto Rico School of Medicine, San Juan, Puerto Rico, USA
| | - Laura Ramírez
- University of Puerto Rico School of Medicine, San Juan, Puerto Rico, USA
| | | | - Christian Schenk
- Universidad Nacional Pedro Henríquez Ureña, Santo Domingo, Republica Dominicana
| | - Daisy Acosta
- Departamento de Neurología y Neurocirugía Hospital Clínico, Departamento de Neurociencias, Centro de Investigación Clínica Avanzada (CICA), Universidad de Chile & Clínica Alemana, Santiago, Chile
| | - María Isabel Behrens
- Becker Medical Library, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michelle Doering
- Department of Biostatistics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Ellen Ziegemeier
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - John C Morris
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Eric McDade
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Randall J Bateman
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
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11
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Ibanez A, Santamaria‐Garcia H, Guerrero Barragan A, Kornhuber A, Ton AMM, Slachevsky A, Teixeira AL, Mar Meza BM, Serrano CM, Cano C, Arias Gonzalez C, Gonzalez‐Billault C, Butler C, Bustin J, Duran‐Aniotz C, Acosta D, Matallana DL, Acosta‐Alvear D, Trépel D, Resende EDPF, de Oliveira FF, Ibanez F, De Felice FG, Navarrete G, Tarnanas I, Meier IB, Smid J, Llibre‐Guerra J, Llibre‐Rodriguez JJ, Fajersztajn L, Takada LT, Duque L, Okada de Oliveira M, Bicalho MAC, Behrens MI, Pintado‐Caipa M, Parra M, Wilson MZ, De La Cruz Puebla M, Custodio N, Santibanez R, Serafim RB, Tavares RM, Piña Escudero SD, Leon Rodriguez T, Dawson W, Miller BL, Kosik KS. The impact of SARS-CoV-2 in dementia across Latin America: A call for an urgent regional plan and coordinated response. Alzheimers Dement (N Y) 2020; 6:e12092. [PMID: 33283036 PMCID: PMC7683959 DOI: 10.1002/trc2.12092] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 09/11/2020] [Indexed: 01/15/2023]
Abstract
The SARS-CoV-2 global pandemic will disproportionately impact countries with weak economies and vulnerable populations including people with dementia. Latin American and Caribbean countries (LACs) are burdened with unstable economic development, fragile health systems, massive economic disparities, and a high prevalence of dementia. Here, we underscore the selective impact of SARS-CoV-2 on dementia among LACs, the specific strain on health systems devoted to dementia, and the subsequent effect of increasing inequalities among those with dementia in the region. Implementation of best practices for mitigation and containment faces particularly steep challenges in LACs. Based upon our consideration of these issues, we urgently call for a coordinated action plan, including the development of inexpensive mass testing and multilevel regional coordination for dementia care and related actions. Brain health diplomacy should lead to a shared and escalated response across the region, coordinating leadership, and triangulation between governments and international multilateral networks.
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Affiliation(s)
- Agustin Ibanez
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Cognitive Neuroscience Center (CNC)Universidad de San AndrésBuenos AiresArgentina
- National Scientific and Technical Research Council (CONICET)Buenos AiresArgentina
- Center for Social and Cognitive Neuroscience (CSCN)Universidad Adolfo Ibanez, School of Psychology, Adolfo Ibañez UniversitySantiagoChile
- Universidad Autónoma del CaribeBarranquillaColombia
| | - Hernando Santamaria‐Garcia
- Pontificia Universidad Javeriana, Bogotá, Departamentos de Psiquiatría, Instituto de Envejecimiento, Centro de Memoria y Cognición IntellectusHospital Universitario San IgnacioBogotáColombia
| | - Alejandra Guerrero Barragan
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Servicio de NeurologíaSubred de Servicios de Salud SuroccidenteBogotáColombia
| | - Alexander Kornhuber
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
| | - Alyne Mendonca Marques Ton
- Laboratory of Translational Physiology and PharmacologyPharmaceutical Sciences Graduate Program, Vila Velha UniversityVila VelhaEspírito SantoBrazil
| | - Andrea Slachevsky
- Memory and Neuropsychiatric Clinic (CMYN), Neurology DepartmentDel Salvador Hospital and University of Chile Faculty of MedicineSantiagoChile
- Geroscience Center for Brain Health and Metabolism (GERO), Faculty of MedicineUniversity of ChileSantiagoChile
- Neuropsychology and Clinical Neuroscience Laboratory (LANNEC), Physiopathology Department ‐ ICBM, Neuroscience and East Neuroscience Departments, Faculty of MedicineUniversity of ChileSantiagoChile
- Department of Neurology and PsychiatryClínica Alemana‐Universidad del DesaConcepciónChile
| | | | - Beatriz Marcela Mar Meza
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
| | - Cecilia M. Serrano
- Cognitive Neurology, Department of NeurologyCésar Milstein Hospital, ALMA (Asociación de Lucha contra el Mal de Alzheimer y alteraciones semejantes de la República Argentina), Research Ethics Committee, Ministry of Health of Buenos AiresBuenos AiresArgentina
| | - Carlos Cano
- Pontificia Universidad Javeriana, Bogotá, Departamentos de Psiquiatría, Instituto de Envejecimiento, Centro de Memoria y Cognición IntellectusHospital Universitario San IgnacioBogotáColombia
| | - Carolina Arias Gonzalez
- Neuroscience Research Institute and Department of Molecular Cellular and Developmental BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Christian Gonzalez‐Billault
- Geroscience Center for Brain Health and Metabolism (GERO), Faculty of MedicineUniversity of ChileSantiagoChile
| | - Christopher Butler
- Department of Brain SciencesImperial CollegeLondonUK
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Department of NeurologyPontificia Universidad Católica de ChileSantiagoChile
| | - Julian Bustin
- Instituto de Neurología CognitivaINCYTBuenos AiresArgentina
| | - Claudia Duran‐Aniotz
- Center for Social and Cognitive Neuroscience (CSCN)Universidad Adolfo Ibanez, School of Psychology, Adolfo Ibañez UniversitySantiagoChile
- Geroscience Center for Brain Health and Metabolism (GERO), Faculty of MedicineUniversity of ChileSantiagoChile
- Biomedical Neuroscience Institute, Faculty of MedicineUniversity of ChileSantiagoChile
| | - Daisy Acosta
- Universidad Nacional Pedro Henriquez Ureña (UNPHU), Internal Medicine DepartmentGeriatric SectionSanto DomingoDominican Republic
| | - Diana L. Matallana
- Pontificia Universidad Javeriana, Bogotá, Departamentos de Psiquiatría, Instituto de Envejecimiento, Centro de Memoria y Cognición IntellectusHospital Universitario San IgnacioBogotáColombia
| | - Diego Acosta‐Alvear
- Neuroscience Research Institute and Department of Molecular Cellular and Developmental BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Dominic Trépel
- Global Brain Health InstituteTrinity College DublinDublinIreland
| | - Elisa De Paula França Resende
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Instituto de Ensino e PesquisaSanta Casa BHBelo HorizonteBrazil
- Federal University of Rio de JaneiroRio de JaneiroBrazil
| | - Fabricio Ferreira de Oliveira
- Department of Neurology and Neurosurgery, Escola Paulista de MedicinaFederal University of São Paulo ‐ UNIFESPSão PauloBrazil
| | | | - Fernanda G. De Felice
- Federal University of Rio de JaneiroRio de JaneiroBrazil
- Queen's UniversityKingstonOntarioCanada
| | - Gorka Navarrete
- Center for Social and Cognitive Neuroscience (CSCN)Universidad Adolfo Ibanez, School of Psychology, Adolfo Ibañez UniversitySantiagoChile
| | - Ioannis Tarnanas
- Altoida Inc.HoustonTexasUSA
- Swiss National Task Force for DementiaGenevaSwitzerland
| | - Irene B. Meier
- Altoida Inc.HoustonTexasUSA
- Swiss National Task Force for DementiaGenevaSwitzerland
| | - Jerusa Smid
- Department of NeurologyUniversity of Sao Paulo; Institute of Infectious Diseases Emilio RibasSão PauloBrazil
| | - Jorge Llibre‐Guerra
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Department of NeurologyWashington University School of MedicineSt LouisUSA
| | | | - Laís Fajersztajn
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Department of Pathology, Laboratory of Experimental Air PollutionUniversity of São Paulo School of MedicineSao PauloBrazil
| | | | - Lissette Duque
- Cognitive Disorders Unit, NeuromedicenterNational Commission in BioethicsQuitoEcuador
| | - Maira Okada de Oliveira
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Hospital das ClinicasUniversity of Sao Paulo Medical SchoolSao PauloBrazil
- Hospital Santa MarcelinaSao PauloBrazil
| | | | - María Isabel Behrens
- Neuropsychology and Clinical Neuroscience Laboratory (LANNEC), Physiopathology Department ‐ ICBM, Neuroscience and East Neuroscience Departments, Faculty of MedicineUniversity of ChileSantiagoChile
- FCEFyNUniversidad Nacional de San JuanSan JuanArgentina
- Departamento de Neurología and Neurocirugía Hospital Clínico, Departamento de NeurocienciasCentro de Investigación Clínica Avanzada (CICA) Facultad de Medicina, Hospital Clínico, Universidad de ChileSantiagoChile
| | - Maritza Pintado‐Caipa
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Unit Cognitive Impairment and Dementia PreventionCognitive Neurology Center, Peruvian Institute of NeurosciencesLimaPeru
| | | | - Maxwell Z. Wilson
- Neuroscience Research Institute and Department of Molecular Cellular and Developmental BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
| | - Myriam De La Cruz Puebla
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Vall d'Hebron Research Institute (VHIR)Autonome University of BarcelonaBarcelonaSpain
| | - Nilton Custodio
- Unit Cognitive Impairment and Dementia PreventionCognitive Neurology Center, Peruvian Institute of NeurosciencesLimaPeru
| | - Rodrigo Santibanez
- Department of NeurologyPontificia Universidad Católica de ChileSantiagoChile
- Neurology ServiceComplejo Asistencial Dr. Sótero del RíoSantiagoChile
| | | | - Ronnielly Melo Tavares
- Federal University of Rio de JaneiroRio de JaneiroBrazil
- Behavioral Neurology ClinicSanta Casa de Belo HorizonteMGBrazil
| | | | - Tomas Leon Rodriguez
- Memory and Neuropsychiatric Clinic (CMYN), Neurology DepartmentDel Salvador Hospital and University of Chile Faculty of MedicineSantiagoChile
| | - Walter Dawson
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
- Department of NeurologySchool of Medicine, Oregon Health and Science UniversityPortlandOregonUSA
- Institute on AgingCollege of Urban and Public Affairs, Portland State UniversityPortlandOregonUSA
| | - Bruce L. Miller
- Global Brain Health Institute (GBHI)University of California San Francisco (UCSF)San FranciscoCaliforniaUSA
| | - Kenneth S. Kosik
- Neuroscience Research Institute and Department of Molecular Cellular and Developmental BiologyUniversity of California Santa BarbaraSanta BarbaraCaliforniaUSA
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12
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Mardones MD, Andaur GA, Varas-Godoy M, Henriquez JF, Salech F, Behrens MI, Couve A, Inestrosa NC, Varela-Nallar L. Frizzled-1 receptor regulates adult hippocampal neurogenesis. Mol Brain 2016; 9:29. [PMID: 26980182 PMCID: PMC4791773 DOI: 10.1186/s13041-016-0209-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/06/2016] [Indexed: 01/19/2023] Open
Abstract
Background In the adult hippocampus new neurons are continuously generated from neural stem cells (NSCs) present at the subgranular zone of the dentate gyrus. This process is controlled by Wnt signaling, which plays a complex role in regulating multiple steps of neurogenesis including maintenance, proliferation and differentiation of progenitor cells and the development of newborn neurons. Differential effects of Wnt signaling during progression of neurogenesis could be mediated by cell-type specific expression of Wnt receptors. Here we studied the potential role of Frizzled-1 (FZD1) receptor in adult hippocampal neurogenesis. Results In the adult dentate gyrus, we determined that FZD1 is highly expressed in NSCs, neural progenitors and immature neurons. Accordingly, FZD1 is expressed in cultured adult hippocampal progenitors isolated from mouse brain. To evaluate the role of this receptor in vivo we targeted FZD1 in newborn cells using retroviral-mediated RNA interference. FZD1 knockdown resulted in a marked decrease in the differentiation of newborn cells into neurons and increased the generation of astrocytes, suggesting a regulatory role for the receptor in cell fate commitment. In addition, FZD1 knockdown induced an extended migration of adult-born neurons within the granule cell layer. However, no differences were observed in total dendritic length and dendritic arbor complexity between control and FZD1-deficient newborn neurons. Conclusions Our results show that FZD1 regulates specific stages of adult hippocampal neurogenesis, being required for neuronal differentiation and positioning of newborn neurons into the granule cell layer, but not for morphological development of adult-born granule neurons.
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Affiliation(s)
- Muriel D Mardones
- Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago, Chile
| | - Gabriela A Andaur
- Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago, Chile
| | - Manuel Varas-Godoy
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de los Andes, Santiago, Chile
| | - Jenny F Henriquez
- Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago, Chile
| | - Felipe Salech
- Unidad de Geriatría, Hospital Clínico Universidad de Chile, Santiago, Chile.,Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - María Isabel Behrens
- Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile.,Clínica Alemana de Santiago, Santiago, Chile
| | - Andrés Couve
- Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile.,Center for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - Lorena Varela-Nallar
- Center for Biomedical Research, Faculty of Biological Sciences and Faculty of Medicine, Universidad Andres Bello, Santiago, Chile.
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13
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Abstract
Brain functioning is mainly intrinsic, not primarily reflexive. This is supported by the high energy requirements of the resting brain (20% of all the energy consumed) which only marginally increases with changes in brain activity. Modern neuroimaging and neurophysiological techniques have led to the discovery of the so called brain default mode network (DMN), a constellation of brain regions which support brain activity at rest and whose discharges decrease during task-induced activities. Another characteristic of the DMN are the elevated levels of aerobic glycolysis (Warburg effect), that is, metabolism of glucose to lactic acid in the presence of sufficient levéis of oxygen. In Alzheimer's disease there is amyloid deposition and metabolic disruption at the DMN regions. Changes in connectivity among the different nodes of the DMN and its connections with the hippocampus have been reported. The characteristics of the DMN and its relation to Alzheimer's disease are discussed. This issue is of interest in the pathogenesis and possibly for its usefulness as a biomarker of the disease.
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14
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Delgado C, Donoso A, Orellana P, Vásquez C, Díaz V, Behrens MI. Frequency and determinants of poststroke cognitive impairment at three and twelve months in Chile. Dement Geriatr Cogn Disord 2010; 29:397-405. [PMID: 20484909 DOI: 10.1159/000305097] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/23/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND A higher risk of poststroke cognitive impairment (CI) has been reported in Hispanics in a US cohort but has not been systematically studied in Latin America. OBJECTIVES Our purpose was to investigate the frequencies and determinants of poststroke CI in the hispano-mestizo population of Santiago, Chile. METHODS A prospective study of hospitalized patients aged >60 years admitted with an ischemic or hemorrhagic stroke was conducted. The cognitive status was determined at 3 and 12 months after the stroke by informant questionnaires, neuropsychological testing and clinical diagnosis. Cardiovascular risk factors, brain imaging and stroke features were analyzed using regression models to establish determinants for poststroke CI. RESULTS A total of 164 patients (mean age = 72 +/- 7.5 years) were recruited. Out of 122 patients (74%) evaluated at 3 months, 81 (66%) had CI. Out of 101 patients (62%) evaluated at 12 months, 39 (39%) had CI no dementia, and 22 (22%) were demented. The new-onset dementia frequency at 1 year was 16%. Independent determinants for dementia were higher functional impairment at hospital egress (OR = 4.0), left-hemisphere large-vessel infarction (OR = 6.9) and a larger amount of white matter changes (OR = 1.3). CONCLUSIONS In this first study on poststroke CI in Latin America, the frequencies and determinants of poststroke CI were similar to those in other cohorts of different ethnic origin.
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Affiliation(s)
- Carolina Delgado
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Santiago, Chile. cdelgado @ med.uchile.cl
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15
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Sinning M, van Rooyen JP, Venegas-Francke P, Vásquez C, Behrens MI, Ramírez A. Clinical and genetic analysis of a Chilean family with early-onset autosomal dominant Alzheimer's disease. J Alzheimers Dis 2010; 21:757-61. [PMID: 20571222 DOI: 10.3233/jad-2010-100135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Autosomal dominant early-onset Alzheimer's disease (ADEOAD) is associated predominantly with mutations in the genes that codify for presenilin 1 (PSEN1). Only a few ADEOAD families have been reported from Latin America. This is an extended Chilean pedigree affected by ADEOAD along 4 generations. The age of onset of dementia was between 38 and 42 years. Early manifestations were anxiety and depression. Mutation analysis revealed a heterozygous G to C transversion at position 438 of the mRNA in PSEN1 in all affected members. This is the first report of a Chilean family with ADEOAD to include mutation analysis.
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Affiliation(s)
- Mariana Sinning
- Departamento de Neurología Neurocirugía, Hospital Clínico de la Universidad de Chile, Santiago, Chile.
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16
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Roe CM, Fitzpatrick AL, Xiong C, Sieh W, Kuller L, Miller JP, Williams MM, Kopan R, Behrens MI, Morris JC. Cancer linked to Alzheimer disease but not vascular dementia. Neurology 2009; 74:106-12. [PMID: 20032288 DOI: 10.1212/wnl.0b013e3181c91873] [Citation(s) in RCA: 185] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To investigate whether cancer is associated with Alzheimer disease (AD) and vascular dementia (VaD). METHODS Cox proportional hazards models were used to test associations between prevalent dementia and risk of future cancer hospitalization, and associations between prevalent cancer and risk of subsequent dementia. Participants in the Cardiovascular Health Study-Cognition Substudy, a prospective cohort study, aged 65 years or older (n = 3,020) were followed a mean of 5.4 years for dementia and 8.3 years for cancer. RESULTS The presence of any AD (pure AD + mixed AD/VaD; hazard ratio [HR] = 0.41, 95% confidence interval [CI] = 0.20-0.84) and pure AD (HR = 0.31, 95% CI = 0.12-0.86) was associated with a reduced risk of future cancer hospitalization, adjusted for demographic factors, smoking, obesity, and physical activity. No significant associations were found between dementia at baseline and rate of cancer hospitalizations for participants with diagnoses of VaD. Prevalent cancer was associated with reduced risk of any AD (HR = 0.72; 95% CI = 0.52-0.997) and pure AD (HR = 0.57; 95% CI = 0.36-0.90) among white subjects after adjustment for demographics, number of APOE epsilon4 alleles, hypertension, diabetes, and coronary heart disease; the opposite association was found among minorities, but the sample size was too small to provide stable estimates. No significant association was found between cancer and subsequent development of VaD. CONCLUSIONS In white older adults, prevalent Alzheimer disease (AD) was longitudinally associated with a reduced risk of cancer, and a history of cancer was associated with a reduced risk of AD. Together with other work showing associations between cancer and Parkinson disease, these findings suggest the possibility that cancer is linked to neurodegeneration.
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Affiliation(s)
- C M Roe
- Alzheimer Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA.
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17
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Abstract
Cancer and Alzheimer's disease (AD) are two common disorders for which the final pathophysiological mechanism is not yet clearly defined. In a prospective longitudinal study we have previously shown an inverse association between AD and cancer, such that the rate of developing cancer in general with time was significantly slower in participants with AD, while participants with a history of cancer had a slower rate of developing AD. In cancer, cell regulation mechanisms are disrupted with augmentation of cell survival and/or proliferation, whereas conversely, AD is associated with increased neuronal death, either caused by, or concomitant with, beta amyloid (Abeta) and tau deposition. The possibility that perturbations of mechanisms involved in cell survival/death regulation could be involved in both disorders is discussed. Genetic polymorphisms, DNA methylation or other mechanisms that induce changes in activity of molecules with key roles in determining the decision to "repair and live"- or "die" could be involved in the pathogenesis of the two disorders. As examples, the role of p53, Pin1 and the Wnt signaling pathway are discussed as potential candidates that, speculatively, may explain inverse associations between AD and cancer.
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Affiliation(s)
- M I Behrens
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile and Clínica Alemana Santiago, Chile.
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18
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Bull R, Finkelstein JP, Gálvez J, Sánchez G, Donoso P, Behrens MI, Hidalgo C. Ischemia enhances activation by Ca2+ and redox modification of ryanodine receptor channels from rat brain cortex. J Neurosci 2008; 28:9463-72. [PMID: 18799678 PMCID: PMC6671122 DOI: 10.1523/jneurosci.2286-08.2008] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [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: 05/21/2008] [Revised: 07/07/2008] [Accepted: 08/04/2008] [Indexed: 01/22/2023] Open
Abstract
Cerebral ischemia stimulates Ca2+ influx and thus increases neuronal intracellular free [Ca2+]. Using a rat model of cerebral ischemia without recirculation, we tested whether ischemia enhances the activation by Ca2+ of ryanodine receptor (RyR) channels, a requisite feature of RyR-mediated Ca2+-induced Ca2+ release (CICR). To this aim, we evaluated how single RyR channels from endoplasmic reticulum vesicles, fused into planar lipid bilayers, responded to cytoplasmic [Ca2+] changes. Endoplasmic reticulum vesicles were isolated from the cortex of rat brains incubated without blood flow for 5 min at 37 degrees C (ischemic) or at 4 degrees C (control). Ischemic brains displayed increased oxidative intracellular conditions, as evidenced by a lower ratio (approximately 130:1) of reduced/oxidized glutathione than controls (approximately 200:1). Single RyR channels from ischemic or control brains displayed the same three responses to Ca2+ reported previously, characterized by low, moderate, or high maximal activity. Relative to controls, RyR channels from ischemic brains displayed with increased frequency the high activity response and with lower frequency the low activity response. Both control and ischemic cortical vesicles contained the RyR2 and RyR3 isoforms in a 3:1 proportion, with undetectable amounts of RyR1. Ischemia reduced [3H]ryanodine binding and total RyR protein content by 35%, and increased at least twofold endogenous RyR2 S-nitrosylation and S-glutathionylation without affecting the corresponding RyR3 endogenous levels. In vitro RyR S-glutathionylation but not S-nitrosylation favored the emergence of high activity channels. We propose that ischemia, by enhancing RyR2 S-glutathionylation, allows RyR2 to sustain CICR; the resulting amplification of Ca2+ entry signals may contribute to cortical neuronal death.
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Affiliation(s)
- Ricardo Bull
- Centro de Estudios Moleculares de la Célula, Fondo de Investigación Avanzada en Areas Prioritarias, Universidad de Chile, Santiago 7, Chile.
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19
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Bull R, Finkelstein JP, Humeres A, Behrens MI, Hidalgo C. Effects of ATP, Mg2+, and redox agents on the Ca2+ dependence of RyR channels from rat brain cortex. Am J Physiol Cell Physiol 2007; 293:C162-71. [PMID: 17360812 DOI: 10.1152/ajpcell.00518.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Despite their relevance for neuronal Ca(2+)-induced Ca(2+) release (CICR), activation by Ca(2+) of ryanodine receptor (RyR) channels of brain endoplasmic reticulum at the [ATP], [Mg(2+)], and redox conditions present in neurons has not been reported. Here, we studied the effects of varying cis-(cytoplasmic) free ATP concentration ([ATP]), [Mg(2+)], and RyR redox state on the Ca(2+) dependence of endoplasmic reticulum RyR channels from rat brain cortex. At pCa 4.9 and 0.5 mM adenylylimidodiphosphate (AMP-PNP), increasing free [Mg(2+)] up to 1 mM inhibited vesicular [(3)H]ryanodine binding; incubation with thimerosal or dithiothreitol decreased or enhanced Mg(2+) inhibition, respectively. Single RyR channels incorporated into lipid bilayers displayed three different Ca(2+) dependencies, defined by low, moderate, or high maximal fractional open time (P(o)), that depend on RyR redox state, as we have previously reported. In all cases, cis-ATP addition (3 mM) decreased threshold [Ca(2+)] for activation, increased maximal P(o), and shifted channel inhibition to higher [Ca(2+)]. Conversely, at pCa 4.5 and 3 mM ATP, increasing cis-[Mg(2+)] up to 1 mM inhibited low activity channels more than moderate activity channels but barely modified high activity channels. Addition of 0.5 mM free [ATP] plus 0.8 mM free [Mg(2+)] induced a right shift in Ca(2+) dependence for all channels so that [Ca(2+)] <30 microM activated only high activity channels. These results strongly suggest that channel redox state determines RyR activation by Ca(2+) at physiological [ATP] and [Mg(2+)]. If RyR behave similarly in living neurons, cellular redox state should affect RyR-mediated CICR.
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Affiliation(s)
- Ricardo Bull
- Facultad de Medicina, Universidad de Chile, Casilla 70005, Santiago 7, Chile.
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20
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Abstract
Cross-sectional studies raise the possibility of protective relationships between, or a common mechanism underlying, the development of dementia of the Alzheimer type (DAT) and cancer. Using a prospective longitudinal design, the authors found that the risk of developing cancer is less among participants with DAT vs nondemented participants (p < 0.001) and that the risk of developing DAT may be less for participants with a history of cancer (p = 0.060).
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Affiliation(s)
- C M Roe
- Division of Biostatistics, Washington University School of Medicine, 660 South Euclid Avenue, Box 8067, St. Louis, MO 63110, USA.
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Behrens MI, Díaz V, Vásquez C, Donoso A. [Dementia caused by vitamin B12 deficiency. Clinical case]. Rev Med Chil 2003; 131:915-9. [PMID: 14558247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Cyanocobalamin (vitamin B12) deficiency can cause polyneuropathy, myelopathy, blindness, confusion, psychosis and dementia. Nonetheless, its deficiency as the sole cause of dementia is infrequent. We report a 59 years old man with a 6 months history of progressive loss of memory, disorientation, apathy, paranoid delusions, gait difficulties with falls, and urinary incontinence. He had suffered a similar episode 3 years before, with a complete remission. On examination there was frontal type dementia with Korsakoff syndrome, a decrease in propioception and ataxic gait. Cerebrospinal fluid examination showed a protein of 0.42 g/L. Brain computed tomography showed sequelae of a frontal left trauma. Brain single photon computed tomography (SPECT) was normal. Complete blood count showed a macrocytic anemia with a hematocrit 29% and a mean corpuscular volume of 117 micron3. Plasma vitamin B12 levels were undetectable, erythrocyte folate levels were 3.9 ng/ml and plasma folate was normal. The myelogram showed megaloblastosis and the gastric biopsy showed atrophic gastritis. Treatment with parenteral B12 vitamin and folic acid reverted the symptoms, with normalization of the neuropsychological tests and reintegration to work.
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Affiliation(s)
- María Isabel Behrens
- Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile
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22
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Bull R, Marengo JJ, Finkelstein JP, Behrens MI, Alvarez O. SH oxidation coordinates subunits of rat brain ryanodine receptor channels activated by calcium and ATP. Am J Physiol Cell Physiol 2003; 285:C119-28. [PMID: 12637263 DOI: 10.1152/ajpcell.00296.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have reported that ryanodine receptor (RyR) channels display three different responses to cytoplasmic free Ca2+ concentration ([Ca2+]) depending on their redox state (Marengo JJ, Hidalgo C, and Bull R. Biophys J 74: 1263-1277, 1998), with low, moderate, and high maximal fractional open times (Po). Activation by ATP of single RyR channels from rat brain cortex was tested in planar lipid bilayers with 10 or 0.1 microM cytoplasmic [Ca2+]. At 10 microM [Ca2+], low-Po channels presented lower apparent affinity to activation by ATP [[ATP] for half-maximal activation (KaATP) = 422 microM] than moderate-Po channels (KaATP = 82 microM). Oxidation of low-Po channels with thimerosal or 2,2'-dithiodipyridine (DTDP) gave rise to moderate-Po channels and decreased KaATP from 422 to 82 microM. At 0.1 microM cytoplasmic [Ca2+], ATP induced an almost negligible activation of low-Po channels. After oxidation to high-Po behavior, activation by ATP was markedly increased. Noise analysis of single-channel fluctuations of low-Po channels at 10 microM [Ca2+] plus ATP revealed the presence of subconductance states, suggesting a conduction mechanism that involves four independent subchannels. On oxidation the subchannels opened and closed in a concerted mode.
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Affiliation(s)
- Ricardo Bull
- Programa de Fisiología y Biofísica, Facultad de Medicina, Universidad de Chile, Santiago 838-0453, Chile
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23
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Lendon CL, Han BH, Salimi K, Fagan AM, Behrens MI, Muller MC, Holtzman DM. No effect of apolipoprotein E on neuronal cell death due to excitotoxic and apoptotic agents in vitro and neonatal hypoxic ischaemia in vivo. Eur J Neurosci 2000; 12:2235-42. [PMID: 10947802 DOI: 10.1046/j.1460-9568.2000.00113.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The epsilon4 allele of apolipoprotein E (apoE) is a genetic risk factor for Alzheimer's disease. Studies also suggest that the epsilon4 allele may be a risk factor for poor outcome following head trauma, brain haemorrhage and ischaemia. The mechanism by which the presence of an apoE epsilon4 allele and certain brain injuries act to predispose to Alzheimer's disease and poor outcome following brain injury is unknown. We questioned whether poor outcome after brain injury was due to direct modification by apoE protein and its gene variants of susceptibility to glutamate-mediated excitotoxic injury and apoptosis, mechanisms of cell death which occur following ischaemia and trauma. We investigated the effect of the presence or absence of endogenous murine apoE protein and different apoE isoforms in modification of the survival of murine embryonic cortical neurons exposed to the glutamate agonist, N-methyl-D-aspartic acid (NMDA) or apoptotic insult by staurosporine, and on the amount of brain injury sustained following a hypoxic-ischaemic insult in vivo to the brain of neonatal mice transgenically expressing human apoE epsilon3 or epsilon4. Our data provide evidence that apoE does not appear to alter neuronal viability following diverse types of acute neuronal insult, e.g. hypoxic-ischaemic or acute exposure to injurious agents in the models we have examined. This suggests that if apoE does modify the extent of brain damage and recovery after injury, it seems unlikely to be a result of direct or indirect modulation of excitotoxic or apoptotic cell death.
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Affiliation(s)
- C L Lendon
- Department of Psychiatry, University of Birmingham, Queen Elizabeth Psychiatric Hospital, UK.
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24
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Abstract
The susceptibility of cortical neurons to two forms of apoptotic death was compared with susceptibility to excitotoxic death during development in vitro (DIV 4-21). Murine cortical cultures were exposed for 48 h to the phosphatase inhibitor cyclosporine, the protein kinase inhibitor staurosporine or the excitotoxin N-methyl-D-aspartate (NMDA). Susceptibility to apoptosis induced by staurosporine or cyclosporine was maximal between DIV 4-10 and declined from DIV 10 through 18. The opposite pattern was observed with susceptibility to NMDA receptor-mediated excitotoxic necrosis, which was minimal at DIV 6 and progressively increased through DIV 21.
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Affiliation(s)
- J W McDonald
- Center for the Study of Nervous System Injury and Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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25
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Abstract
The small subpopulation of striatal neurons containing nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d, recently identified as nitric oxide synthase, NOS) is selectively spared in Huntington's disease. Previous search for pathogenic mechanisms capable of destroying striatal neurons but sparing NADPH-d(+) cells has identified only NMDA receptor-mediated excitotoxicity. In view of suggestions that neuronal death in Huntington's disease may occur by apoptosis, we examined the vulnerability of NADPH-d(+) neurons to apoptosis. Murine striatal or cortical cultures exposed to serum deprivation developed extensive neuronal apoptosis, but NADPH-d(+) neurons were relatively spared. This sparing was seen when cultures were exposed to several other apoptosis-inducing insults. It was not seen after toxic exposure to H2O2, and it was not blocked by NOS inhibition. The selective resistance of NADPH-d(+) neurons to several forms of apoptosis provides key support for the possibility that apoptosis may contribute to the pathogenesis of Huntington's disease.
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Affiliation(s)
- M I Behrens
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Ramírez BU, Behrens MI, Vergara C. Neural control of the expression of a Ca(2+)-activated K+ channel involved in the induction of myotonic-like characteristics. Cell Mol Neurobiol 1996; 16:39-49. [PMID: 8714558 DOI: 10.1007/bf02578385] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
1. Expression of the apamin-sensitive K+ channel (SK+) in rat skeletal muscle is neurally regulated. The regulatory effect of the nerve over the expression of some muscle ion channels has been attributed to the electrical activity triggered by the nerve and/or to a trophic effect of some molecules transported from the soma to the axonal endings. 2. SK+ channels apparently are involved in myotonic dystrophy (MD), therefore understanding the factors that regulate their expression may ultimately have important clinical relevance. 3. To establish if axoplasmic transport is involved in this process, we used two experimental approaches in adult rats: (a) Both sciatic nerves were severed, leaving a short or a long nerve stump attached to the anterior tibialis (AT). (b) Colchicine or vinblastine (VBL), two axonal transport blockers of different potencies, was applied on one leg to the sciatic nerve. To determine whether electrical activity affects the expression of SK+ channels, denervated AT were directly stimulated. The corresponding contralateral muscles were used as controls.
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Affiliation(s)
- B U Ramírez
- Departamento de Enfermedades Respiratorias, Universidad Católica de Chile, Santiago
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27
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Abstract
Ingestion of 3-nitropropionic acid (3-NPA) in moldy sugar cane causes brain damage in children. The mechanism of 3-NPA toxicity is thought to be inhibition of energy production, leading to ATP depletion and excitotoxicity. We exposed cultured mouse striatal or cortical neurons to 1-2 mM 3-NPA for 48 h. This exposure produced gradual neuronal degeneration characterized by cell body shrinkage and DNA fragmentation. Addition of glutamate antagonists during 3-NPA exposure did not reduce neuronal death. However, addition of the macromolecular synthesis inhibitors cycloheximide, emetine or actinomycin D markedly reduced neuronal death. Our results do not exclude that 3-NPA can induce excitotoxicity in more intact systems, but raise the additional possibility that 3-NPA may also act to induce neuronal apoptosis.
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Affiliation(s)
- M I Behrens
- Center for the Study of Nervous System Injury, Washington University School of Medicine, St Louis, MO 63110, USA
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28
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Abstract
Myotonic muscular dystrophy is a genetic disease characterized mainly by muscle atrophy and myotonia, a repetitive electrical activity of muscle. In the present study, the possible role of apamin-sensitive K+ channels in the genesis of myotonia was investigated. Apamin is a peptide from bee venom that specifically blocks small conductance Ca(2+)-activated K+ channels. The injection of a small amount of apamin (20-30 microliters, 10 mumol/L) into the thenar muscle of myotonic dystrophy patients decreased the basal electrical activity during the electromyogram in the 6 patients studied. Myotonic discharges after muscle percussion were more difficult to trigger and of smaller intensity and duration. In 2 controls and in 2 patients with generalized myotonia, as well as in 1 patient with myotonia congenita (where the defect is in chloride channels), apamin had no effect. These results suggest that apamin-sensitive K+ channels participate in the mechanism that generates myotonia in myotonic dystrophy.
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Affiliation(s)
- M I Behrens
- Servicio de Neurología, Hospital Dr. Sótero del Río, Santiago, Chile
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29
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Abstract
A low conductance calcium-activated K+ channel is thought to regulate the rate of firing of several excitable cells. In skeletal muscle the expression of this channel is under nerve control. Previously, we reported that axonal flow blockade of rat nerves, induced by colchicine, caused a transient increase in muscle apamin receptors, determined by 125I-apamin binding to membrane fractions. The increase in apamin receptors was correlated with repetitive discharges resembling myotonic potentials in the electromyogram, that were blockable by apamin. Here we show that the increase in muscle apamin receptors and the alteration of the electromyogram are followed closely by a slowing of the twitch relaxation, that in turn, is decreased by apamin. Furthermore, the presence of myotonic-like alterations in the electromyogram and a slowing of muscle relaxation when muscle apamin receptors are increased suggests that these channels may participate, among other factors, in the generation of some kinds of myotonia.
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Affiliation(s)
- C Vergara
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago
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30
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Abstract
We have shown an increase of apamin receptors in rat skeletal muscle membranes following the application of colchicine to the sciatic nerve. 125I-apamin binding to partially purified membrane fractions was observed since day 4, reached a maximum around days 6-15, and was negligible at day 35 after the application of colchicine. Control muscles (nerves treated with buffer solution) showed low binding values (11 fmol/mg protein). Maximal 125I-apamin binding values to partially purified muscle membranes of colchicine-treated rats (42 fmol/mg protein) were lower than those obtained in denervated muscle (95 fmol/mg protein). The affinity binding constant values were 37 (colchicine) and 95 pM (denervation). No signs of muscle denervation were observed on histological examination of the nerve submitted to colchicine treatment nor in the muscles innervated by it. Muscle tension developed by indirect stimulation was the same as in controls. We here show also that partially purified membranes of normal untreated muscles have measurable amounts of 125I-apamin binding (13 fmol/mg protein), similar to those obtained in control muscles. Electromyographic recordings of the muscles after colchicine treatment of the nerve showed abnormal repetitive electrical discharges, similar to myotonic discharges, that were present with a similar temporal course as the increase in apamin receptors. The myotonic-like discharges were suppressed by the topical application of apamin to the muscle, whereas the toxin had no effect on anthracene-9-carbolytic acid-induced myotonia. Our results suggest that a neurotrophic factor that travels by axonal flow is involved in the regulation of the expression of apamin receptors in skeletal muscle membranes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M I Behrens
- Centro de Estudios Cientificos de Santiago; Hospital Dr. Sótero del Rio, Chile
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Baizabal-Aguirre VM, Behrens MI, Gómez-Puyou A, Tuena de Gómez-Puyou M. Effect of pyridine nucleotides on ATP synthesis and hydrolysis by the mitochondrial ATPase. Biochem Int 1990; 22:677-84. [PMID: 2150308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The effect of NADH, NAD+, NADPH, and NADP+ on succinate driven ATP synthesis of Mg-ATP submitochondrial particles and on ATP hydrolysis in soluble and particulate F1 from bovine heart was studied. Hydrolysis was inhibited competitively by all pyridine nucleotides when the concentration of Mg [gamma 32P]-ATP was varied between 0.1 mM to 3 mM, but NAD+ was less effective. Succinate driven ATP synthesis at various concentrations of ADP was also inhibited by the four pyridine nucleotides, but NADH was much more effective. Increasing concentrations of phosphate decreased the extent of the NADH induced inhibition of ATP synthesis. The effect of various parts of the NADH molecule on ATP synthesis was tested; the order of inhibition by these compounds was: NADH greater than ADP-ribose greater than NAD+ greater than NADPH greater than NADP+ greater than nicotinamide mononucleotide greater than nicotinamide.
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32
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Behrens MI, Oberhauser A, Bezanilla F, Latorre R. Batrachotoxin-modified sodium channels from squid optic nerve in planar bilayers. Ion conduction and gating properties. J Gen Physiol 1989; 93:23-41. [PMID: 2536797 PMCID: PMC2216204 DOI: 10.1085/jgp.93.1.23] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Squid optic nerve sodium channels were characterized in planar bilayers in the presence of batrachotoxin (BTX). The channel exhibits a conductance of 20 pS in symmetrical 200 mM NaCl and behaves as a sodium electrode. The single-channel conductance saturates with increasing the concentration of sodium and the channel conductance vs. sodium concentration relation is well described by a simple rectangular hyperbola. The apparent dissociation constant of the channel for sodium is 11 mM and the maximal conductance is 23 pS. The selectivity determined from reversal potentials obtained in mixed ionic conditions is Na+ approximately Li+ greater than K+ greater than Rb+ greater than Cs+. Calcium blocks the channel in a voltage-dependent manner. Analysis of single-channel membranes showed that the probability of being open (Po) vs. voltage relation is sigmoidal with a value of 0.5 between -90 and -100 mV. The fitting of Po requires at least two closed and one open state. The apparent gating charge required to move through the whole transmembrane voltage during the closed-open transition is four to five electronic charges per channel. Distribution of open and closed times are well described by single exponentials in most of the voltage range tested and mean open and mean closed times are voltage dependent. The number of charges associated with channel closing is 1.6 electronic charges per channel. Tetrodotoxin blocked the BTX-modified channel being the blockade favored by negative voltages. The apparent dissociation constant at zero potential is 16 nM. We concluded that sodium channels from the squid optic nerve are similar to other BTX-modified channels reconstituted in bilayers and to the BTX-modified sodium channel detected in the squid giant axon.
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Affiliation(s)
- M I Behrens
- Centro de Estudios Científicos de Santiago, Chile
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33
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Grossmann D, Behrens MI. [Immunostimulation in the lymphadenopathy syndrome and in AIDS--Inosiplex (inosin pranobex, methisoprinol]. Onkologie 1987; 10:12-6. [PMID: 2443884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In patients with AIDS, LAS and ARC a defect in producing lymphokines such as Interleukin 2 and Gamma-interferon is found. Possibilities of therapy are reported. Especially the immunostimulant properties of inosiplex are commented, and the first successful results of therapy are discussed.
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de Meis L, Behrens MI, Celis H, Romero I, Gómez Puyou MT, Gómez Puyou A. Orthophosphate-pyrophosphate exchange catalyzed by soluble and membrane-bound inorganic pyrophosphatases. Role of H+ gradient. Eur J Biochem 1986; 158:149-57. [PMID: 3015606 DOI: 10.1111/j.1432-1033.1986.tb09732.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A comparative study of the orthophosphate-pyrophosphate exchange reaction catalyzed by the soluble pyrophosphatase from baker's yeast and by the membrane-bound pyrophosphatase of Rhodospirillum rubrum chromatophores was performed. In both systems the rate of exchange increased when the pH of the medium was raised from 6.0 to 7.8 and when the MgCl2 concentration was raised from 0.1 mM to 20 mM. For the yeast pyrophosphatase the exchange rates measured at different pH values and in the presence of 6.7 to 8.8 mM free Mg2+ superimposed as a single curve when plotted as a function of the concentrations of either HPO4(2-) or MgHPO4. This was not observed with the use of R. rubrum chromatophores. With yeast pyrophosphatase, the Km for Pi was higher than 10 mM and could not be measured when the free Mg2+ concentration in the medium was lower than 0.5 mM. There was a decrease in the Km for Pi when the free Mg2+ concentration was raised to 6.7-8.8 mM or when, in the presence of low free Mg2+, the organic solvents dimethylsulfoxide (20% v/v) or ethyleneglycol (40% v/v) were included in the assay medium. In the presence of 6.7-8.8 mM free Mg2+ the Km for total Pi was 7 mM at pH 7.0 and 12 mM at pH 7.8. For the ionic species HPO4(2-) and MgHPO4, the Km values were 5.8 mM and 4.2 mM respectively. In the presence of 0.24-0.42 mM free Mg2+ and either 20% (v/v) dimethylsulfoxide or 40% (v/v) ethyleneglycol the Km values for total Pi, HPO4(2-) and MgHPO4 were 7.6, 3.5 and 0.5 mM respectively. With R. rubrum chromatophores, the Km for Pi in the presence of 5.5-7.5 mM free Mg2+ was very high and could not be measured. In the presence of 0.24-0.45 mM free Mg2+ the ratio between the velocities of hydrolysis and synthesis of pyrophosphate measured at pH 7.8 with yeast pyrophosphatase and chromatophores of R. rubrum were practically the same. When the free Mg2+ concentration was raised to 5.5-8.8 mM this ratio decreased from 1028 to 540 when the yeast pyrophosphatase was used and from 754 to 46 when chromatophores were used.
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Abstract
The energy of hydrolysis of phosphate compounds varies depending on whether they are in solution or bound to the catalytic site of enzymes. With the purpose of simulating the conditions at the catalytic site, the observed equilibrium constant for pyrophosphate hydrolysis (Kobsd) was measured in aqueous mixtures of dimethyl sulfoxide, ethylene glycol, or polymers of ethylene glycol. The reaction was catalyzed by yeast inorganic pyrophosphatase at 30 degrees C. All the cosolvents used promoted a decrease of Kobsd. Polymers of ethylene glycol were more effective than dimethyl sulfoxide or ethylene glycol in decreasing Kobsd. The higher the molecular weight of the polymer, the lower the value of Kobsd. A decrease in Kobsd from 346 M (delta G degree obsd = -3.5 kcal mol-1) to 0.1 M (delta G degree obsd = 1.3 kcal mol-1) was observed after the addition of 50% (w/v) poly(ethylene glycol) 8000 to a solution containing 0.9 mM MgCl2 and 1 mM Pi at pH 8.0. The association constants of Pi and pyrophosphate for H+ and Mg2+ were measured in presence of different ethylene glycol concentrations in order to calculate the Keq for hydrolysis of different ionic species of pyrophosphate. A decrease in all the Keq was observed. The results are interpreted according to the concept that the energy of hydrolysis of phosphate compounds depends on the different solvation energies of reactants and products.
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Behrens MI, De Meis L. Synthesis of pyrophosphate by chromatophores of Rhodospirillum rubrum in the light and by soluble yeast inorganic pyrophosphatase in water-organic solvent mixtures. Eur J Biochem 1985; 152:221-7. [PMID: 2995032 DOI: 10.1111/j.1432-1033.1985.tb09187.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chromatophores of Rhodospirillum rubrum contain a membrane-bound pyrophosphatase that synthesizes pyrophosphate when an electrochemical H+ gradient is formed across the chromatophore membrane upon illumination. In this report it is shown that MgCl2 and Pi have different effects on the synthesis of pyrophosphate in the light depending on whether initial velocities or steady-state levels are examined. When the water activity of the medium is reduced by the addition of organic solvents, soluble yeast inorganic pyrophosphatase (no H+ gradient present) synthesizes pyrophosphate in amounts similar to those synthesized by the chromatophores in totally aqueous medium during illumination, (H+ gradient present). The pH, MgCl2 and Pi dependence for the synthesis of pyrophosphate by the chromatophores at steady-state is similar to that observed at equilibrium with the soluble enzyme in the presence of organic solvents. The possibility is raised that a decrease in water activity may play a role in the mechanism by which the energy derived from the electrochemical H+ gradient is used for the synthesis of pyrophosphate in chromatophores of R. rubrum.
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Abstract
The effect of heparin, a sulphated glycosaminoglycan, on the solubilization of rat sciatic-nerve acetylcholinesterase (acetylcholine acetylhydrolase; AChE; EC 3.1.1.7) was studied. It was found that heparin solubilized esterase activity from ligated nerves. Sedimentation analysis revealed this activity to be mainly the 16S form. Chondroitin sulphate did not solubilize AChE activity, and protamine eliminated the solubilizing effect. Our results suggest the involvement of sulphated glycosaminoglycans in the intra-axonal localization and transport of 16S AChE.
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Abstract
The chronic administration of nafenopin, a hypolipidemic drug, induced an increase in catalase and acyl-CoA oxidase activities in various skeletal muscles, including the gracilis, diaphragm, soleus, and extensor digitorum longus. The magnitude of the increase was around 100% for both enzymes in each of the muscles studied in spite of the different basal level. These changes seem to be specific of the peroxisomal enzymes because acetylcholinesterase, which is not peroxisomal, did not follow the same pattern in all the muscles. Concomitant with the increase in muscle peroxisomal enzymes, the skeletal muscles presented an altered electromyogram with prolonged insertional activity, repetitive firing of action potentials, and myotonic runs characteristic of myotonia. Our results suggest a role for peroxisomes in the myotonic disorder.
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Abstract
Axonal transport of acetylcholinesterase (AChE) was measured in the median and sural nerves of a subject who suffered from dystrophia myotonica and in a control subject. It was found that the basal activity of AChE was increased in myotonic nerves while its proximodistal transport was inhibited.
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Luco J, Behrens MI. [New concepts on homeostasis (author's transl)]. Arch Biol Med Exp 1980; 13:209-12. [PMID: 7259207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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41
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Behrens MI, Fernandez O, Luco JV. Modification of the Rosenblueth phenomenon by blockage of axonal flow. Brain Res 1980; 194:521-4. [PMID: 6155978 DOI: 10.1016/0006-8993(80)91235-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
Rosenblueth and Luco demonstrated in 1939 that, during prolonged stimulation of a motor nerve, neuromuscular fatigue is followed by a rise of tension that has been called the Rosenblueth Phenomenon. The purpose of this work was to investigate the Rosenblueth Phenomenon in a cat neuromuscular preparation in which the nerves were severed at different levels and stimulated at 60 Hz for several hours. It was demonstrated that in the longer nerve preparation the Rosenblueth Phenomenon starts earlier and its maximal tension is higher. Acetylcholine sensitivity was studied in the superior cervical ganglion preparation and no change was observed when tested before stimulation, during fatigue, and during the Rosenblueth Phenomenon. It is concluded that the onset and amplitude of the Rosenblueth Phenomenon depend on the length of the peripheral nerve stump: the longer the stump, the earlier and higher the response. It is suggested that the Rosenblueth Phenomenon is produced by an increase in the transmitter release which would be due to axonal progression of molecules along the nerve.
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Behrens MI, Rosenthal AJ, Chodoff P. Communication in lower class families of schizophrenics. II. Observations and findings. Arch Gen Psychiatry 1968; 18:689-96. [PMID: 5651512 DOI: 10.1001/archpsyc.1968.01740060049006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Rosenthal AJ, Behrens MI, Chodoff P. Communication in lower class families of schizophrenics. I. Methodological problems. Arch Gen Psychiatry 1968; 18:464-70. [PMID: 5650779 DOI: 10.1001/archpsyc.1968.01740040080010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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45
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