EEG Correlates of Spikes in Intracranial Pressure Caused by Transient Ventriculoperitoneal Shunt Malfunction.

SUMMARY: A 30-year-old man with recurrent headaches and seizure-like activity and a 26-year-old woman with worsening headaches were admitted to the hospital. Both had ventriculoperitoneal shunts and history of several shunt revisions for congenital hydrocephalus. The ventricle size visualized on computed tomography scans was unremarkable, and shunt series were negative in both cases. Both patients began to present with brief periods of unresponsiveness, and video electroencephalography at that time showed periods of diffuse delta slowing. Lumbar punctures revealed increased opening pressures. Despite normal imaging and shunt series, both patients ultimately had increased intracranial pressure caused by shunt malfunction. This series demonstrates the difficulty of diagnosing potential transient increases in intracranial pressure based on standard-of-care diagnostics/examination and the potentially critical role for EEG in the identification of shunt malfunction.

A data management and publication workflow for a large-scale, heterogeneous sensor network.

It is common for hydrology researchers to collect data using in situ sensors at high frequencies, for extended durations, and with spatial distributions that produce data volumes requiring infrastructure for data storage, management, and sharing. The availability and utility of these data in addressing scientific questions related to water availability, water quality, and natural disasters relies on effective cyberinfrastructure that facilitates transformation of raw sensor data into usable data products. It also depends on the ability of researchers to share and access the data in useable formats. In this paper, we describe a data management and publication workflow and software tools for research groups and sites conducting long-term monitoring using in situ sensors. Functionality includes the ability to track monitoring equipment inventory and events related to field maintenance. Linking this information to the observational data is imperative in ensuring the quality of sensor-based data products. We present these tools in the context of a case study for the innovative Urban Transitions and Aridregion Hydrosustainability (iUTAH) sensor network. The iUTAH monitoring network includes sensors at aquatic and terrestrial sites for continuous monitoring of common meteorological variables, snow accumulation and melt, soil moisture, surface water flow, and surface water quality. We present the overall workflow we have developed for effectively transferring data from field monitoring sites to ultimate end-users and describe the software tools we have deployed for storing, managing, and sharing the sensor data. These tools are all open source and available for others to use.

Association between an Alzheimer's Disease-Related Index and APOE ε4 Gene Dose.

BACKGROUND: We introduced a hypometabolic convergence index (HCI) to characterize in a single measurement the extent to which a person's fluorodeoxyglucose positron emission tomogram (FDG PET) corresponds to that in Alzheimer's disease (AD). Apolipoprotein E ε4 (APOE ε4) gene dose is associated with three levels of risk for late-onset AD. We explored the association between gene dose and HCI in cognitively normal ε4 homozygotes, heterozygotes, and non-carriers. METHODS: An algorithm was used to characterize and compare AD-related HCIs in cognitively normal individuals, including 36 ε4 homozygotes, 46 heterozygotes, and 78 non-carriers. RESULTS: These three groups differed significantly in their HCIs (ANOVA, p = 0.004), and there was a significant association between HCIs and gene dose (linear trend, p = 0.001). CONCLUSIONS: The HCI is associated with three levels of genetic risk for late-onset AD. This supports the possibility of using a single FDG PET measurement to help in the preclinical detection and tracking of AD.

Blood pressure is associated with higher brain amyloid burden and lower glucose metabolism in healthy late middle-age persons.

Epidemiological studies suggest that elevated blood pressure (BP) in midlife is associated with increased risk of Alzheimer's disease (AD) in late life. In this preliminary study, we investigated the extent to which BP measurements are related to positron emission tomography (PET) measurements of fibrillar amyloid-beta burden using Pittsburgh Compound-B (PiB) and fluorodeoxyglucose (FDG) PET measures of cerebral metabolic rate for glucose metabolism (CMRgl) in cognitively normal, late middle-aged to older adult apolipoprotein E (APOE) ε4 homozygotes, heterozygotes and noncarriers. PiB PET results revealed that systolic BP (SBP) and pulse pressure (PP) were each positively correlated with cerebral-to-cerebellar PiB distribution volume ratio (DVR) in frontal, temporal, and posterior-cingulate/precuneus regions, whereas no significant positive correlations were found between PiB distribution volume ratios and diastolic BP (DBP). FDG PET results revealed significant inverse correlations between each of the BP measures and lower glucose metabolism in frontal and temporal brain regions. These preliminary findings provide additional evidence that higher BP, likely a reflection of arterial stiffness, during late midlife may be associated with increased risk of presymptomatic AD.

Hypometabolism in Alzheimer-affected brain regions in cognitively healthy Latino individuals carrying the apolipoprotein E epsilon4 allele.

OBJECTIVE: To investigate with fluorodeoxyglucose positron emission tomography whether regional reductions in the cerebral metabolic rate for glucose (CMRgl) previously found in cognitively healthy late-middle-aged apolipoprotein E (APOE) epsilon4 carriers extend to members of the Latino Mexican American community. DESIGN: Prospective cohort study. SETTING: Banner Alzheimer's Institute, Phoenix, Arizona. PATIENTS OR OTHER PARTICIPANTS: Eleven APOE epsilon4 carriers and 16 noncarriers from Arizona's Latino community (mean [SD] age, 54.6 [6.4] years) matched for sex, mean age, and educational level and who were predominantly of self-designated Mexican origin. MAIN OUTCOME MEASURE: A brain mapping algorithm was used to compare cross-sectional regional CMRgl in Latino APOE epsilon4 carriers vs noncarriers. RESULTS: Participant groups had similar distributions for age, sex, education, family history of dementia, clinical ratings, and neuropsychological test scores. Latino APOE epsilon4 carriers had lower CMRgl than the noncarriers in the posterior cingulate, precuneus, and parietal regions previously found to be preferentially affected in patients with Alzheimer disease (AD) and cognitively healthy non-Latino APOE epsilon4 carriers. Additionally, the Latino APOE epsilon4 carriers had lower CMRgl in the middle and anterior cingulate cortex, hippocampus, and thalamus. CONCLUSIONS: This study provides support for the relationship between APOE epsilon4 and risk of AD in Latino individuals. It illustrates the role of positron emission tomography as a presymptomatic endophenotype for the assessment of AD risk factors and supports the inclusion of Latino APOE epsilon4 carriers in proof-of-concept studies using fluorodeoxyglucose PET to evaluate promising presymptomatic treatments in cognitively healthy carriers of this common AD susceptibility gene.

Fibrillar amyloid-beta burden in cognitively normal people at 3 levels of genetic risk for Alzheimer's disease.

Fibrillar amyloid-beta (Abeta) is found in the brains of many cognitively normal older people. Whether or not this reflects a predisposition to Alzheimer's disease (AD) is unknown. We used Pittsburgh Compound B (PiB) PET to characterize the relationship between fibrillar Abeta burden and this predisposition in cognitively normal older people at 3 mean levels of genetic risk for AD. Dynamic PiB PET scans, the Logan method, statistical parametric mapping, and automatically labeled regions of interest (ROIs) were used to characterize and compare cerebral-to-cerebellar PIB distribution volume ratios, reflecting fibrillar Abeta burden, in 28 cognitively normal persons (mean age, 64 years) with a reported family history of AD and 2 copies, 1 copy, and no copies of the apolipoprotein E (APOE) epsilon4 allele. The 8 epsilon4 homozygotes, 8 heterozygotes, and 12 noncarriers did not differ significantly in terms of age, sex, or cognitive scores. Fibrillar Abeta was significantly associated with APOE epsilon4 carrier status and epsilon4 gene dose in AD-affected mean cortical, frontal, temporal, posterior cingulate-precuneus, parietal, and basal ganglia ROIs, and was highest in an additional homozygote who had recently developed mild cognitive impairment. These findings suggest that fibrillar Abeta burden in cognitively normal older people is associated with APOE epsilon4 gene dose, the major genetic risk factor for AD. Additional studies are needed to track fibrillar Abeta accumulation in persons with different kinds and levels of AD risk; to determine the extent to which fibrillar Abeta, alone or in combination with other biomarkers and risk factors, predicts rates of cognitive decline and conversion to clinical AD; and to establish the role of fibrillar Abeta imaging in primary prevention trials.

Contemporary imaging of the temporomandibular joint.

This article discusses imaging techniques for visualization of the temporomandibular joint. Conventional plain film modalities are discussed briefly, with an emphasis on the more contemporary modalities, such as CT with cone-beam technology, MRI, and nuclear imaging, including single-photon emission computed tomography, and positron emission tomography. Indications, advantages, and limitations are discussed. As advancements in this area continue, our understanding of this complex joint and its pathology will follow, which will lead to more defined imaging indications and ultimately, to improved treatment outcomes.

Dopamine (D2/3) receptor agonist positron emission tomography radiotracer [11C]-(+)-PHNO is a D3 receptor preferring agonist in vivo.

[11C]PHNO is a recently introduced agonist to image DA D2-like receptors with Positron Emission Tomography (PET). In cats and humans, [11C]PHNO revealed an atypical distribution compared to radiolabeled D2-like antagonists (such as [11C]raclopride) or other D2-like agonists (such as [11C]NPA), as it displayed unusual high binding in the globus pallidus (GP). The goal of this study was to assess the pharmacological nature of the binding of [11C]PHNO in the GP in nonhuman primates. As previously reported in humans, [11C]PHNO equilibrium specific to nonspecific equilibrium partition coefficients (V3'') in baboons was much higher in GP (3.88 +/- 1.15) than in the dorsal striatum (DST, 2.07 +/- 0.43), whereas the reverse was true for [11C]raclopride (1.48 +/- 0.41 in GP, 2.56 +/- 0.91 in DST) and [11C]NPA (0.87 +/- 0.19 in GP, 1.02 +/- 0.13 in DST). Administration of unlabeled raclopride resulted in similar reductions of [11C] PHNO V3'' and [11C]raclopride V3'' in both the GP and the DST. This observation demonstrated that the [11C]PHNO binding in the GP was specific to D2-like receptors. To evaluate the respective contribution of D3 and D2 receptors to the binding potential (BP) of [11C]PHNO and [11C]raclopride, experiments were carried out with the selective D3 partial agonist 1-(4(2-Napthoylamino)butyl)-4-(2-methoxyphenyl)-1A-piperazine HCL (BP897). BP897 reduced [11C]raclopride V3'' by 29% +/- 9%, 19% +/- 8%, and 10% +/- 7% in GP, VST, and DST, respectively, a result consistent with expectation from postmortem studies (D3/D2 ratio in GP > VST > DST). BP897 reduced [11C]PHNO V3'' by 57% +/- 11%, 30% +/- 11%, and 13% +/- 8% in GP, VST, and DST, respectively, indicating that the D3 receptor contribution to [11C]PHNO signal is higher than that of [11C]raclopride. From these experiments we conclude that [11C]PHNO is a D3 preferring agonist, and that this property explains the high GP signal not observed with [11C]raclopride or [11C]NPA. This property might contribute to its higher vulnerability to endogenous DA compared to [11C]raclopride and [11C]NPA.