ABSTRACT Using a spectroscopically confirmed sample of M giants, M dwarfs, and quasars from the LAMOST survey, we assess how well Wide-field Infrared Survey Explorer (WISE) and Two Micron All Sky ...Survey color cuts can be used to select M giant stars. The WISE bands are very efficient at separating M giants from M dwarfs, and we present a simple classification that can produce a clean and relatively complete sample of M giants. We derive a new photometric relation to estimate the metallicity for M giants, calibrated using data from the APOGEE survey. We find a strong correlation between the color and , where almost all of the scatter is due to photometric uncertainties. We show that previous photometric distance relations, which are mostly based on stellar models, may be biased and devise a new empirical distance relation, investigating trends with metallicity and star formation history. Given these relations, we investigate the properties of M giants in the Sagittarius stream. The offset in the orbital plane between the leading and trailing tails is reproduced, and by identifying distant M giants in the direction of the Galactic anticenter, we confirm that the previously detected debris in the outer halo is the apocenter of the trailing tail. We also find tentative evidence supporting an existing overdensity near the leading tail in the northern Galactic hemisphere, possibly an extension to the trailing tail (so-called Branch C). We have measured the metallicity distribution along the stream, finding a clear metallicity offset between the leading and trailing tails, in agreement with models for the stream formation. We include an online table of M giants to facilitate further studies.
4-F-18fluoro-N-{2-4-(2-methoxyphenyl)-1-piperazinylethyl}-N-(2pyridinyl)benzamide, a selective serotonin 1A ($5-HT_{1A}$) molecular imaging probe, was used in conjunction with positron emission ...tomography (PET) for quantification of$5-HT_{1A}$receptor densities in the living brains of Alzheimer's disease patients (ADs) (n = 8), subjects with mild cognitive impairment (n = 6), and controls (n = 5). ADs had receptor densities significantly decreased in both hippocampi (binding potential: controls 1.62 ± 0.07; ADs 1.18 ± 0.26) and also in raphe nuclei (controls 0.63 ± 0.09; ADs 0.37 ± 0.20). When volume losses are included,$5-HT_{1A}$losses are even more severe (i.e., average mean decreases of 24% in mild cognitive impairment patients and 49% in ADs). A strong correlation of$5-HT_{1A}$receptor decreases in hippocampus with worsening of clinical symptoms (Mini Mental State Exam scores) was also found. Moreover, these decreases in$5-HT_{1A}$receptor measures correlate with decreased glucose utilization as measured with 2-deoxy-2-F-18fluoro-D-glucose PET in the brains of ADs (standardized uptake values: globally: controls 0.89 ± 0.04, ADs 0.72 ± 0.04; posterior cingulate gyrus: controls 1.05 ± 0.09. ADs 0.79 ± 0.11). They also inversely correlate with increased neuropathological loads measured with 2-(1-{6-(2-(2-F-18fluoroethyl)(methyl)amino-2-naphthylethylidene)malononitrite PET in several neocortical regions in the same subjects. The in vivo observations were confirmed independently by in vitro digital autoradiography with 4-F-18fluoro-N-{2-4-(2-methoxyphenyl)-1-piperazinyljethyl}-N-(2-pyridinyl)benz-amide and 2-(1-{6-(2-F-18fluoroethyl)(methyl)amino-2-naphthyl-ethylidene)malononitrile on brain tissue specimens from two ADs and three nondemented subjects.
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When optical navigation images acquired by the OSIRIS‐REx (Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer) mission revealed the periodic ejection of ...particles from asteroid (101955) Bennu, it became a mission priority to quickly identify and track these objects for both spacecraft safety and scientific purposes. The large number of particles and the mission criticality rendered time‐intensive manual inspection impractical. We present autonomous techniques for particle detection and tracking that were developed in response to the Bennu phenomenon but that have the capacity for general application to particles in motion about a celestial body. In an example OSIRIS‐REx data set, our autonomous techniques identified 93.6% of real particle tracks and nearly doubled the number of tracks detected versus manual inspection alone.
Key Points
We describe autonomous techniques for the identification and tracking of particles in motion about a celestial body
We demonstrate these techniques using images from the OSIRIS‐REx mission to the active asteroid (101955) Bennu
In the OSIRIS‐REx dataset, our autonomous algorithms detected 93.6% of real particle tracks, including 244 tracks not identified by manual inspection
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The major known genetic risk for Alzheimer's disease (AD), apollpoprotein E-4 (APOE-4), is associated with lowered parietal, temporal, and posterior cingulate cerebral glucose metabolism in patients ...with a clinical diagnosis of AD. To determine cognitive and metabolic decline patterns according to genetic risk, we investigated cerebral metabolic rates by using positron emission tomography in middle-aged and older nondemented persons with normal memory performance. A single copy of the APOE-4 allele was associated with lowered inferior parietal, lateral temporal, and posterior cingulate metabolism, which predicted cognitive decline after 2 years of longitudinal follow-up. For the 20 nondemented subjects followed longitudinally, memory performance scores did not decline significantly, but cortical metabolic rates did. In APOE-4 carriers, a 4% left posterior cingulate metabolic decline was observed, and inferior parietal and lateral temporal regions demonstrated the greatest magnitude (5%) of metabolic decline after 2 years. These results indicate that the combination of cerebral metabolic rates and genetic risk factors provides a means for preclinical AD detection that will assist in response monitoring during experimental treatments.
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Purpose
The aim of this study was to investigate the longitudinal positron emission tomography (PET) metabolic changes in the elderly.
Procedures
Nineteen nondemented subjects (mean Mini-Mental ...Status Examination 29.4 ± 0.7 SD) underwent two detailed neuropsychological evaluations and resting 2-deoxy-2-F-18fluoro-
d
-glucose (FDG)-PET scan (interval 21.7 ± 3.7 months), baseline structural 3T magnetic resonance (MR) imaging, and apolipoprotein E4 genotyping. Cortical PET metabolic changes were analyzed in 3-D using the cortical pattern matching technique.
Results
Baseline vs. follow-up whole-group comparison revealed significant metabolic decline bilaterally in the posterior temporal, parietal, and occipital lobes and the left lateral frontal cortex. The declining group demonstrated 10–15% decline in bilateral posterior cingulate/precuneus, posterior temporal, parietal, and occipital cortices. The cognitively stable group showed 2.5–5% similarly distributed decline. ApoE4-positive individuals underwent 5–15% metabolic decline in the posterior association cortices.
Conclusions
Using 3-D surface-based MR-guided FDG-PET mapping, significant metabolic changes were seen in five posterior and the left lateral frontal regions. The changes were more pronounced for the declining relative to the cognitively stable group.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Purpose We evaluated whether plasma Alzheimer disease (AD)–related biomarkers were associated with cancer-related cognitive decline among older breast cancer survivors. Methods We included ...survivors aged 60-90 years with primary stage 0-III breast cancers (n = 236) and frequency-matched noncancer control paricipant (n = 154) who passed a cognitive screen and had banked plasma specimens. Participants were assessed at baseline (presystemic therapy) and annually for up to 60 months. Cognition was measured using tests of attention, processing speed, and executive function and learning and memory; perceived cognition was measured by the Functional Assessment of Cancer Therapy-Cognitive Function v3 Perceived Cognitive Impairments. Baseline plasma neurofilament light, glial fibrillary acidic protein, β-amyloid 42 and 40 and phosphorylated tau 181 were assayed using single molecule arrays. Mixed models tested associations between cognition and baseline AD biomarkers, time, group (survivor vs control participant), and their 2- and 3-way interactions, controlling for age, race, Wide Range 4 Achievement Test Word Reading score, comorbidity, and body mass index; 2-sided P values of .05 were considered statistically significant. Results There were no group differences in baseline AD-related biomarkers except survivors had higher baseline neurofilament light levels than control participants (P = .013). Survivors had lower adjusted longitudinal attention, processing speed, and executive function than control participants starting from baseline and continuing over time (P ≤ .002). However, baseline AD-related biomarker levels were not independently associated with adjusted cognition over time, except control participants had lower attention, processing speed, and executive function scores with higher glial fibrillary acidic protein levels (P = .008). Conclusion The results do not support a relationship between baseline AD-related biomarkers and cancer-related cognitive decline. Further investigation is warranted to confirm the findings, test effects of longitudinal changes in AD-related biomarkers, and examine other mechanisms and factors affecting cognition presystemic therapy.
Background: The apolipoprotein E (ApoE) ϵ4 allele confers significant risk for Alzheimer’s disease and is associated with a greater amyloid burden in the brain. Future treatments may target molecular ...mechanisms associated with this allele, and it is important to define any phenotypic characteristics that correspond to this genotype. We sought to clarify the relationship between ApoE status and noncognitive symptoms in Alzheimer’s disease patients.
Methods: Possible and probable Alzheimer’s disease patients from a clinical trial (
n = 605) were assessed with the 10-item Neuropsychiatric Inventory cross-sectionally prior to treatment, and their ApoE genotype was determined. Among the population studied, the following numbers with specific genotypes were studied: 23–2/3, 17–2/4, 209–3/3, 288–3/4, 68–4/4.
Results: When correlations were controlled for the patient’s level of cognitive impairment, there was no relationship between ϵ4 dose and any of the 10 noncognitive symptoms assessed, including psychosis, mood changes, and personality alterations.
Conclusions: Among patients with comparable disease severity, the ϵ4 allele does not confer additional psychiatric morbidity.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
It is difficult to accurately forecast the clinical course of many patients presenting with mild cognitive problems. The utility in prognostic evaluation of various parameters of brain structure and ...function that can now be noninvasively measured remains to be clearly defined. The present work examined the value of regional cerebral metabolism, assessed with positron emission tomography (PET) and
18Ffluoro-2-deoxyglucose, in this context. PET scans of 167 patients (mean Mini-Mental State Examination (MMSE)=24 of 30 possible points) were classified as being positive or negative for evidence of progressive dementia. Results of scans were compared to patients’ subsequent clinical course in general and in particular, to their changes in MMSE scores, for up to 10 years following PET. Data were further stratified according to the predictions of referring physicians based upon clinical assessments that had been performed up until the time of PET. Among those patients for whom a progressive dementing course had been predicted by PET criteria (but not those who were predicted by PET criteria to remain stable) a significant decline in general cognitive performance and MMSE scores occurred in the period following PET. Among those patients predicted by clinical criteria to have a progressive dementing illness, 94% of those with positive PET scans did suffer a progressive decline, while only 25% of those with negative scans progressed (relative risk 3.8). Similarly, among those patients who had been predicted by clinical criteria to remain cognitively stable, 74% of those with positive PET scans nevertheless suffered progressive decline, compared with 4% of those with negative PET scans (relative risk 18.4). These data indicate that evaluation of brain metabolism by PET in appropriately selected patients may improve the accuracy of clinical prognostic assessment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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