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Cognitive Reserve Associated with FDG-PET in Preclinical Alzheimer Disease

OBJECTIVE: To examine the effect of education (a surrogate measure of cognitive reserve) on FDG-PET brain metabolism in elderly cognitively healthy (HC) subjects with preclinical Alzheimer disease (AD). METHODS: Fifty-two HC subjects (mean age 75 years) with FDG-PET and CSF measurement of Abeta1-42 were included from the prospective Alzheimer's Disease Neuroimaging Initiative biomarker study. HC subjects received a research classification of preclinical AD if CSF Abeta1-42 was <192 pg/mL (Abeta1-42 [+]) vs HC with normal Abeta (Abeta1-42 [-]). In regression analyses, we tested the interaction effect between education and CSF Abeta1-42 status (Abeta1-42 [+] vs Abeta1-42 [-]) on FDG-PET metabolism in regions of interest (ROIs) (posterior cingulate, angular gyrus, inferior/middle temporal gyrus) and the whole brain (voxel-based). RESULTS: An interaction between education and CSF Abeta1-42 status was observed for FDG-PET in the posterior cingulate (p < 0.001) and angular gyrus ROIs (p = 0.03), but was not significant for the inferior/middle temporal gyrus ROI (p = 0.06), controlled for age, sex, and global cognitive ability (Alzheimer's Disease Assessment Scale-cognitive subscale). The interaction effect was such that higher education was associated with lower FDG-PET in the Abeta1-42 (+) group, but with higher FDG-PET in the Abeta1-42 (-) group. Voxel-based analysis showed that this interaction effect was primarily restricted to temporo-parietal and ventral prefrontal brain areas. CONCLUSIONS: Higher education was associated with lower FDG-PET in preclinical AD (Abeta1-42 [+]), suggesting that cognitive reserve had a compensatory function to sustain cognitive ability in presence of early AD pathology that alters FDG-PET metabolism.

Department: 
Neurology
Publication type: 
Author: 
Michael Ewers
Philip S. Insel
Yaakov Stern
Michael W. Weiner
Subjects: 
Neurology
Alzheimer's disease
Cognition
Education
Brain--Metabolism
Title string: 
Cognitive Reserve Associated with FDG-PET in Preclinical Alzheimer Disease
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:80gb5mkkz3

Bias Effects in the Possible/Impossible Object Decision Test with Matching Objects

In the possible/impossible object decision test, priming has consistently been found for structurally possible, but not impossible, objects, leading Schacter, Cooper, and Delaney (1990) to suggest that priming relies on a system that represents the global 3-D structure of objects. Using a modified design with matching objects to control for the influence of episodic memory, Ratcliff and McKoon (1995) and Williams and Tarr (1997) found negative priming for impossible objects (i.e., lower performance for old than for new items). Both teams argued that priming derives from (1) episodic memory for object features and (2) bias to respond "possible" to encoded objects or their possible parts. The present study applied the matched-objects design to the original Schacter and Cooper stimuli-same possible objects and matching impossible figures-with minimal procedural variation. The data from Experiment 1 only partially supported the bias models and suggested that priming was mediated by both local and global structural descriptions. Experiment 2 showed that negative priming for impossible objects derived from the structural properties of these objects, not from the influence of episodic memory on task performance. Supplemental materials for this study may be downloaded from mc.psychonomic-journals.org/content/supplemental.

Department: 
Neurology
Topic: 
Publication type: 
Author: 
Anja Soldan
John Hilton
Yaakov Stern
Subjects: 
Neurology
Decision making--Testing
Prejudices
Cognition
Title string: 
Bias Effects in the Possible/Impossible Object Decision Test with Matching Objects
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:3r2280gb76

A Comparison of Cerebral Spect Abnormalities in Hiv-Positive Homosexual Men with and without Cognitive Impairment

Objective: To determine whether technetium Tc 99m exametazime (HMPAO) single-photon emission computed tomography (SPECT) can distinguish between human immunodeficiency virus (HIV)-positive homosexual men with normal neuropsychologic test results and HIV-positive homosexual men with abnormal neuropsychologic test results. Design: Neurologic, neuropsychologic, magnetic resonance imaging, and Tc 99m HMPAO SPECT examinations were performed on 10 HIV-positive homosexual men without cognitive impairment and five HIV-positive homosexual men with cognitive impairment. Patients: Human immunodeficiency virus—positive homosexual men from New York City were recruited for the study. Main Outcome Measures: Findings on SPECT scans were evaluated qualitatively for focal defects, heterogeneity of the cortical margin, white matter hypoperfusion, and decreased global cortical uptake. All SPECT focal defects were coregistered with magnetic resonance images; SPECT heterogeneity and global cortical uptake were also measured quantitatively. Results: Coregistration with magnetic resonance imaging revealed that 63% of the focal SPECT defects corresponded to brain gyri and 37% corresponded to sulci. There was no significant difference in the frequency of qualitative or quantitative SPECT abnormalities between HIV-positive homosexual men with and without cognitive impairment. However, after examining individual neuropsychologic test factors, impaired motor speed performance was associated with decreased quantitative global cerebral uptake. Conclusions: Qualitative SPECT abnormalities are not increased in frequency in HIV-positive homosexual men with global cognitive impairment compared with those in HIV-positive homosexual men without cognitive impairment. Impaired motor speed performance may be associated with decreased quantitative global cerebral uptake.

Department: 
Neurology
Topic: 
UNI: 
Publication type: 
Author: 
Ned Sacktor
Van Ronald L. Heertum
George Dooneief
Jack M. Gorman
Alexander Khandji
Karen Marder
Ramy Nour
George Todak
Yaakov Stern
Richard Paul Mayeux
Subjects: 
Neurology
HIV-positive persons
Gay men
Cognition
Single-photon emission computed tomography
Title string: 
A Comparison of Cerebral Spect Abnormalities in Hiv-Positive Homosexual Men with and without Cognitive Impairment
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:rfj6q573qj

3D Pharmacophoric Similarity improves Multi Adverse Drug Event Identification in Pharmacovigilance

Adverse drugs events (ADEs) detection constitutes a considerable concern in patient safety and public health care. For this reason, it is important to develop methods that improve ADE signal detection in pharmacovigilance databases. Our objective is to apply 3D pharmacophoric similarity models to enhance ADE recognition in Offsides, a pharmacovigilance resource with drug-ADE associations extracted from the FDA Adverse Event Reporting System (FAERS). We developed a multi-ADE predictor implementing 3D drug similarity based on a pharmacophoric approach, with an ADE reference standard extracted from the SIDER database. The results showed that the application of our 3D multi-type ADE predictor to the pharmacovigilance data in Offsides improved ADE identification and generated enriched sets of drug-ADE signals. The global ROC curve for the Offsides ADE candidates ranked with the 3D similarity score showed an area of 0.7. The 3D predictor also allows the identification of the most similar drug that causes the ADE under study, which could provide hypotheses about mechanisms of action and ADE etiology. Our method is useful in drug development, screening potential adverse effects in experimental drugs, and in drug safety, applicable to the evaluation of ADE signals selected through pharmacovigilance data mining.

UNI: 
Publication type: 
Author: 
Vilar Santiago Varela
Nicholas P. Tatonetti
George M. Hripcsak
Subjects: 
Drugs--Side effects
Medical care
Bioinformatics
Medicine
Title string: 
3D Pharmacophoric Similarity improves Multi Adverse Drug Event Identification in Pharmacovigilance
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:69p8cz8wbs

Using iterative learning to improve understanding during the informed consent process in a South African psychiatric genomics study

Obtaining informed consent is a great challenge in global health research. There is a need for tools that can screen for and improve potential research participants’ understanding of the research study at the time of recruitment. Limited empirical research has been conducted in low and middle income countries, evaluating informed consent processes in genomics research. We sought to investigate the quality of informed consent obtained in a South African psychiatric genomics study. A Xhosa language version of the University of California, San Diego Brief Assessment of Capacity to Consent Questionnaire (UBACC) was used to screen for capacity to consent and improve understanding through iterative learning in a sample of 528 Xhosa people with schizophrenia and 528 controls. We address two questions: firstly, whether research participants’ understanding of the research study improved through iterative learning; and secondly, what were predictors for better understanding of the research study at the initial screening? During screening 290 (55%) cases and 172 (33%) controls scored below the 14.5 cut-off for acceptable understanding of the research study elements, however after iterative learning only 38 (7%) cases and 13 (2.5%) controls continued to score below this cut-off. Significant variables associated with increased understanding of the consent included the psychiatric nurse recruiter conducting the consent screening, higher participant level of education, and being a control. The UBACC proved an effective tool to improve understanding of research study elements during consent, for both cases and controls. The tool holds utility for complex studies such as those involving genomics, where iterative learning can be used to make significant improvements in understanding of research study elements. The UBACC may be particularly important in groups with severe mental illness and lower education levels. Study recruiters play a significant role in managing the quality of the informed consent process.

Publication type: 
Author: 
Megan M. Campbell
Ezra S. Susser
Sumaya Mall
Sibonile G. Mqulwana
Michael M. Mndini
Odwa A. Ntola
Mohamed Nagdee
Zukiswa Zingela
Van Stephanus Wyk
Dan Stein
Subjects: 
Medical ethics
Public health--Research
Informed consent (Medical law)
Learning
Psychiatry
Title string: 
Using iterative learning to improve understanding during the informed consent process in a South African psychiatric genomics study
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:8931zcrjfv

Reaching global HIV/AIDS goals: What got us here, won't get us there

A decade ago, today’s progress towards confronting the global HIV epidemic would have been unimaginable. A remarkable global mobilization of resources through the United States President’s Emergency Plan for AIDS Relief (PEPFAR) and the Global Fund for AIDS, Tuberculosis and Malaria, combined with the commitment of affected countries and communities, has enabled 19.5 million persons living with HIV (PLHIV) to access life-saving antiretroviral therapy (ART) [1]. This has resulted in decreasing HIV-related morbidity and mortality and contributed to a significant decline in the number of new infections [1].

Topic: 
UNI: 
Publication type: 
Author: 
Wafaa Mahmoud El-Sadr
Katherine Harripersaud
Miriam Rabkin
Subjects: 
AIDS (Disease)
HIV infections—Prevention
Public health
HIV infections--Treatment
Sustainable Development Goals
Title string: 
Reaching global HIV/AIDS goals: What got us here, won't get us there
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:gxd2547db1

Estimates of fire emissions from an active deforestation region in the southern Amazon based on satellite data and biogeochemical modelling

Tropical deforestation contributes to the build-up of atmospheric carbon dioxide in the atmosphere. Within the deforestation process, fire is frequently used to eliminate biomass in preparation for agricultural use. Quantifying these deforestation-induced fire emissions represents a challenge, and current estimates are only available at coarse spatial resolution with large uncertainty. Here we developed a biogeochemical model using remote sensing observations of plant productivity, fire activity, and deforestation rates to estimate emissions for the Brazilian state of Mato Grosso during 2001–2005. Our model of DEforestation CArbon Fluxes (DECAF) runs at 250-m spatial resolution with a monthly time step to capture spatial and temporal heterogeneity in fire dynamics in our study area within the ''arc of deforestation'', the southern and eastern fringe of the Amazon tropical forest where agricultural expansion is most concentrated. Fire emissions estimates from our modelling framework were on average 90 Tg C year−1, mostly stemming from fires associated with deforestation (74%) with smaller contributions from fires from conversions of Cerrado or pastures to cropland (19%) and pasture fires (7%). In terms of carbon dynamics, about 80% of the aboveground living biomass and litter was combusted when forests were converted to pasture, and 89% when converted to cropland because of the highly mechanized nature of the deforestation process in Mato Grosso. The trajectory of land use change from forest to other land uses often takes more than one year, and part of the biomass that was not burned in the dry season following deforestation burned in consecutive years. This led to a partial decoupling of annual deforestation rates and fire emissions, and lowered interannual variability in fire emissions. Interannual variability in the region was somewhat dampened as well because annual emissions from fires following deforestation and from maintenance fires did not covary, although the effect was small due to the minor contribution of maintenance fires. Our results demonstrate how the DECAF model can be used to model deforestation fire emissions at relatively high spatial and temporal resolutions. Detailed model output is suitable for policy applications concerned with annual emissions estimates distributed among post-clearing land uses and science applications in combination with atmospheric emissions modelling to provide constrained global deforestation fire emissions estimates. DECAF currently estimates emissions from fire; future efforts can incorporate other aspects of net carbon emissions from deforestation including soil respiration and regrowth.

UNI: 
Publication type: 
Author: 
van der G. R. Werf
D. C. Morton
Ruth S. DeFries
L. Giglio
James T. Randerson
P. S. Kasibhatla
Subjects: 
Deforestation--Environmental aspects
Clearing of land--Environmental aspects
Atmospheric carbon dioxide--Measurement
Biogeochemistry
Title string: 
Estimates of fire emissions from an active deforestation region in the southern Amazon based on satellite data and biogeochemical modelling
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:c59zw3r23q

Multiplanar strain quantification for assessment of right ventricular dysfunction and non-ischemic fibrosis among patients with ischemic mitral regurgitation

Background:
Ischemic mitral regurgitation (iMR) predisposes to right ventricular (RV) pressure and volume overload, providing a nidus for RV dysfunction (RVDYS) and non-ischemic fibrosis (NIF). Echocardiography (echo) is widely used to assess iMR, but performance of different indices as markers of RVDYS and NIF is unknown.

Methods:
iMR patients prospectively underwent echo and cardiac magnetic resonance (CMR) within 72 hours. Echo quantified iMR, assessed conventional RV indices (TAPSE, RV-S’, fractional area change [FAC]), and strain via speckle tracking in apical 4-chamber (global longitudinal strain [RV-GLS]) and parasternal long axis orientation (transverse strain). CMR volumetrically quantified RVEF, and assessed ischemic pattern myocardial infarction (MI) and septal NIF.

Results:
73 iMR patients were studied; 36% had RVDYS (EF<50%) on CMR among whom LVEF was lower, PA systolic pressure higher, and MI size larger (all p<0.05). CMR RVEF was paralleled by echo results; correlations were highest for RV-GLS (r = 0.73) and lowest for RV-S’ (r = 0.43; all p<0.001). RVDYS patients more often had CMR-evidenced NIF (54% vs. 7%; p<0.001). Whereas all RV indices were lower among NIF-affected patients (all p≤0.006), percent change was largest for transverse strain (48.3%). CMR RVEF was independently associated with RV-GLS (partial r = 0.57, p<0.001) and transverse strain (r = 0.38, p = 0.002) (R = 0.78, p<0.001). Overall diagnostic performance of RV-GLS and transverse strain were similar (AUC = 0.93[0.87–0.99]|0.91[0.84–0.99], both p<0.001), and yielded near equivalent sensitivity and specificity (85%|83% and 80%|79% respectively).

Conclusion:
Compared to conventional echo indices, RV strain parameters yield stronger correlation with CMR-defined RVEF and potentially constitute better markers of CMR-evidenced NIF in iMR.

Topic: 
Publication type: 
Author: 
Di Antonino Franco
Jiwon Kim
Sara Rodriguez-Diego
Omar Khalique
Jonathan Y. Siden
Samantha R. Goldburg
Neil K. Mehta
Aparna Srinivasan
Mark B. Ratcliffe
Robert A. Levine
Filippo Crea
Richard B. Devereux
Jonathan Weinsaft
Subjects: 
Heart--Right ventricle
Cardiology
Medicine
Echocardiography
Title string: 
Multiplanar strain quantification for assessment of right ventricular dysfunction and non-ischemic fibrosis among patients with ischemic mitral regurgitation
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:0cfxpnvx1s

Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century

As a result of global increases in both temperature and specific humidity, heat stress is projected to intensify throughout the 21st century. Some of the regions most susceptible to dangerous heat and humidity combinations are also among the most densely populated. Consequently, there is the potential for widespread exposure to wet bulb temperatures that approach and in some cases exceed postulated theoretical limits of human tolerance by mid- to late-century. We project that by 2080 the relative frequency of present-day extreme wet bulb temperature events could rise by a factor of 100–250 (approximately double the frequency change projected for temperature alone) in the tropics and parts of the mid-latitudes, areas which are projected to contain approximately half the world's population. In addition, population exposure to wet bulb temperatures that exceed recent deadly heat waves may increase by a factor of five to ten, with 150–750 million person-days of exposure to wet bulb temperatures above those seen in today's most severe heat waves by 2070–2080. Under RCP 8.5, exposure to wet bulb temperatures above 35 °C—the theoretical limit for human tolerance—could exceed a million person-days per year by 2080. Limiting emissions to follow RCP 4.5 entirely eliminates exposure to that extreme threshold. Some of the most affected regions, especially Northeast India and coastal West Africa, currently have scarce cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. In the coming decades heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training.

Topic: 
Publication type: 
Author: 
Ethan Coffel
Radley M. Horton
De Alexander M. Sherbinin
Subjects: 
Heat--Physiological effect
Humidity--Physiological effect
Atmospheric temperature
Humidity
Climatic changes
Title string: 
Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:f4qrfj6q71

Pollution from Fossil-Fuel Combustion is the Leading Environmental Threat to Global Pediatric Health and Equity: Solutions Exist

Fossil-fuel combustion by-products are the world’s most significant threat to children’s health and future and are major contributors to global inequality and environmental injustice. The emissions include a myriad of toxic air pollutants and carbon dioxide (CO2), which is the most important human-produced climate-altering greenhouse gas. Synergies between air pollution and climate change can magnify the harm to children. Impacts include impairment of cognitive and behavioral development, respiratory illness, and other chronic diseases—all of which may be “seeded“ in utero and affect health and functioning immediately and over the life course. By impairing children’s health, ability to learn, and potential to contribute to society, pollution and climate change cause children to become less resilient and the communities they live in to become less equitable. The developing fetus and young child are disproportionately affected by these exposures because of their immature defense mechanisms and rapid development, especially those in low- and middle-income countries where poverty and lack of resources compound the effects. No country is spared, however: even high-income countries, especially low-income communities and communities of color within them, are experiencing impacts of fossil fuel-related pollution, climate change and resultant widening inequality and environmental injustice. Global pediatric health is at a tipping point, with catastrophic consequences in the absence of bold action. Fortunately, technologies and interventions are at hand to reduce and prevent pollution and climate change, with large economic benefits documented or predicted. All cultures and communities share a concern for the health and well-being of present and future children: this shared value provides a politically powerful lever for action. The purpose of this commentary is to briefly review the data on the health impacts of fossil-fuel pollution, highlighting the neurodevelopmental impacts, and to briefly describe available means to achieve a low-carbon economy, and some examples of interventions that have benefited health and the economy.

Publication type: 
Author: 
Frederica P. Perera
Subjects: 
Air--Pollution--Health aspects
Fossil fuels--Combustion--Environmental aspects
Children--Health and hygiene
Child development
Environmental justice
Title string: 
Pollution from Fossil-Fuel Combustion is the Leading Environmental Threat to Global Pediatric Health and Equity: Solutions Exist
GUID update: 
https://academiccommons.columbia.edu/catalog/ac:zpc866t1js

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